Library

X
Language
Preferred search index
Number of Hits per Page
Default Sort Criterion
Default Sort Ordering
Size of Search History
Default Email Address
Default Export Format
Default Export Encoding
Facet list arrangement
Maximum number of values per filter
Auto Completion
Feed Format
Maximum Number of Items per Feed
Permalink If you want to be able to use settings permanently, you must save your settings and then set a Bookmark to the permalink
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Electronic Resource  (1,739)
  • 1995-1999  (1,728)
  • 1955-1959  (11)
  • Theoretical, Physical and Computational Chemistry  (1,576)
  • transformation
  • 1
    Electronic Resource
    Electronic Resource
    A Modular Vector for Agrobacterium Mediated Transformation of Wheat (1999)
    Springer
    Plant molecular biology reporter 17 (1999), S. 323-331 
    Details
    ISSN: 1572-9818
    Keywords: Agrobacterium ; modular vector ; transformation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat (cv Chinese Spring) tissues were transformed using Agrobacterium tumefasciens and a new plasmid modular vector, pMVTBP. We constructed pMVTBP with unique restriction sites connecting (1) the CaMV 35S promoter, (2) a Kozak sequence, (3) the FLAG epitope, (4) the (His)6 epitope, (5) a coding region (for wheat TATA Binding Protein, wTBP) and (6) the CaMV 35S 3′UTR. This vector thus allows easy exchange of different regulatory or coding sequences. Explants of either germinating mature seeds, or immature embryos, were induced to callus for up to two weeks, treated with virulence-induced bacteria for one hour, then regenerated into plantlets. Transient expression of a GUS reporter gene, assayed at about one week, occurred in 10–12% of calluses. Expression of the FLAG-tagged wTBP was also detected, by immunostaining. Stable expression, by selective growth on geneticin, and by GUS expression at about six weeks, occurred in 1–2% of calluses, quite comparable to that achieved by other methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007686408369
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Polymorphism in Polyamide of Dytek®-A and Dodecanedioic Acid (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1133-1140 
    Details
    ISSN: 1572-8943
    Keywords: branched diamine ; melting ; polyamides ; polymorphism ; transformation ; WXRD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Our X-ray work of Dytek®-A, 2-methyl-pentamethylenediamine, containing polyamides shows polymorphism, whereas the polyamides with linear diamines do not. The polyamide of Dytek®-A and dodecanedioic acid, MPMD-12, is singled out for discussion and compared with the unbranched analogs of polyamides 6,12 and 5,12. Due to the presence of the -CH3 side group in the 2-position of the diamine, the polyamide MPMD-12 exhibits two stable crystal conformations. The new δ polymorph is not seen in linear polyamides 6,12 and 5,12. Studies by DSC polyamide MPMD-12 clearly illustrates at least two crystal forms, γ and δ, coexisting over a wide temperature range, and the isolation of each phase is possible by controlling temperature and time. The DMA modulus in the temperature region between the glass transition (or alpha relaxation) and melting transition shows strong dependence on the thermal history as demonstrated in a study of crystallization kinetics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010105028316
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Agrobacterium‐mediated transformation of lavandin (Lavandula x intermedia Emeric ex Loiseleur) (1999)
    Springer
    Transgenic research 8 (1999), S. 335-347 
    Details
    ISSN: 1573-9368
    Keywords: Agrobacterium tumefaciens ; ß‐glucuronidase ; lamiaceae ; lavandin ; neomycin phosphotransferase II ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lavandin (Lavandula x Emeric ex Loiseleur) is an aromatic plant, the essential oil of which is widely used in the perfume, cosmetic, flavouring and pharmaceutical industries. The qualitative or quantitative modification of its terpenes‐containing essential oil by genetic engineering could have important scientific and commercial applications. In this study, we report the first Agrobacterium tumefaciens‐mediated gene transfer into lavandin. The transformation protocol was optimized by lengthening precultivation and cocultivation periods and by testing five different bacterial strains. We obtained transformed callus lines at a frequency of 40–70 with strains AGL1/GI, EHA105/GI and C58/GI. Transgenic shoots were regenerated from these kanamycin resistant calli and rooted on selective medium with 150 mg l-1 kanamycin. The final percentage of transgenic plants obtained varied from 3 to 9, according to the strain used, within 6 months of culture. The presence of the introduced β‐glucuronidase and neomycin phosphotransferase II genes was shown both by PCR and Southern blot analysis. Transgene expression was investigated using histoenzymatic β‐glucuronidase assays, leaf callus assays and RT‐PCR. Results showed that both β‐glucuronidase and neomycin phosphotransferase II genes were expressed at a high level in at least 41 of the transgenic plants regenerated. This efficient transformation strategy could be used to modify some genetic traits of lavandin (flower colour, pathogens resistance) and to study the biosynthesis of the major monoterpene components of its essential oil (linalool, linalyl acetate, camphor and 1,8‐cineole).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008948113305
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Expression of the Bar Gene Confers Herbicide Resistance in Transgenic Lettuce (1999)
    Springer
    Transgenic research 8 (1999), S. 33-44 
    Details
    ISSN: 1573-9368
    Keywords: Lactuca sativa ; Agrobacterium tumefaciens ; bialaphos ; phosphinothricin acetyltransferase ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Resistance to bialaphos, a broad-spectrum herbicide, was introduced into Lactuca sativa cv. Evola by Agrobacterium tumefaciens-mediated transformation. A. tumefaciens strains 0310 and 1310, both carrying the bialaphos resistance (bar) and neomycin phosphotransferase (nptII) genes, were used for transformation. Primary transformants were selected on kanamycin sulphate-supplemented shoot regeneration medium. Integration of both transgenes was confirmed by non-radioactive Southern hybridisation. The hypervirulent plasmid ToK47 in A. tumefaciens strain 1310 generated multiple insertions of T-DNA in some transgenic plants; the absence of pToK47 (strain 0310) resulted in single gene inserts in all plants tested. Resistance to glufosinate ammonium was observed in axenic seedlings grown on medium supplemented with the herbicide at 5 mg l−1 and in glasshouse-grown plants sprayed with the compound at 300 mg l−1. Stable expression of the bar gene was observed in R2 generation plants. The kanamycin resistance of R1 seedlings was observed by germinating seeds on medium supplemented with 200 mg l−1 kanamycin sulphate. The presence of NPTII protein and PAT enzyme activity were demonstrated by ELISA and PAT enzyme assay respectively. Transgenes segregated in a Mendelian fashion in some plant lines in the R1 generation; herbicide resistance also segregated in the expected ratio in the R2 generation in most transgenic lines. This study confirmed that an agronomically important transgene can be integrated and stably expressed over several generations in lettuce.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008891216134
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Transformation of pasta wheat (Triticum turgidum L. var. durum) with high-molecular-weight glutenin subunit genes and modification of dough functionality (1999)
    Springer
    Molecular breeding 5 (1999), S. 377-386 
    Details
    ISSN: 1572-9788
    Keywords: Triticum turgidum L. var. durum ; pasta wheat ; transformation ; seed protein modification ; flour quality improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Particle bombardment has been used to transform three cultivars (L35, Ofanto, Svevo) and one breeding line (Latino × Lira) of durum wheat (Triticum turgidum L. var. durum). These varieties were co-transformed with plasmids containing selectable and scorable marker genes (bar and uidA) and plasmids containing one of two high-molecular-weight (HMW) glutenin subunit genes (encoding subunits 1Ax1 or 1Dx5). Ten independent transgenic lines were recovered from 1683 bombarded scutella (transformation efficiency thus 0.6%). Five lines expressed either subunit 1Dx5 or 1Ax1 at levels similar to those of endogenous subunits encoded on chromosome 1B. To identify the effects of the transgenes on the functional properties of grain, three lines showing segregation for transgene expression were used to isolate sibling T2 plants which were null or positive for the transgene product. Analysis of these plants using a small-scale mixograph showed that expression of the additional subunits resulted in increased dough strength and stability, demonstrating that transformation can be used to modify the quality of durum wheat for bread and pasta making.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009681321708
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Transformation of the endospermous legume guar (Cyamopsis tetragonoloba L.) and analysis of transgene transmission (1999)
    Springer
    Molecular breeding 5 (1999), S. 521-529 
    Details
    ISSN: 1572-9788
    Keywords: Cyamopsis tetragonoloba ; β-lactamase inhibitor ; sulbactam ; transformation ; transgene stability ; transgenic guar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A procedure for transformation of the large-seeded endospermous legume guar (Cyamopsis tetragonoloba L.) and a study on transmission of the transgenes to offspring generations are presented. Using Agrobacterium tumefaciens with a T-DNA construct harbouring a β-glucuronidase gene (uidA) and a neomycin phosphotransferase gene (nptII), maximum transformation frequencies of cotyledonary explants were obtained using 145 mg/l kanamycin sulfate as selective agent. Carbenicillin and cefotaxime, used for the elimination of Agrobacterium after co-culture, displayed considerable toxicity to guar tissues but replacing most of these β-lactams by the non-phytotoxic β-lactamase inhibitor sulbactam as well as addition of thidiazuron and silver thiosulfate increased transformation frequencies up to 10-fold in total. The presence of the transgenes in the primary transformants was demonstrated by genomic DNA analysis of GUS-positive shoots. Chimaeric plants (5–10%) were identified by GUS analysis at the flowering stage and were discarded. Analysis of the R1 offspring from 17 independent transformants showed that in 41% of those, the uidA gene(s) was expressed and stably inherited consistent with Mendelian genetics. This was also found for the R2 and R3 generations of single copy transformants. On the other hand, a large proportion (47%) of the primary transformants gave R1 offspring in which 100% of the plants were GUS-negative. Analysis of these plants by PCR revealed that, at least, most of the transgene sequences were absent, suggesting that they had not been transmitted from the parent transformants. This occurred at similar high frequencies (40–50%) irrespective of the estimated copy number of the transgenes. Thus, major parts of the transgenes, even when present in multiple copies, displayed aberrant transmission, at a high frequency, in the process of going from the primary transformants to the first offspring generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009602722423
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Partial male sterility in transgenic tobacco carrying an antisense gene for alternative oxidase under the control of a tapetum-specific promoter (1999)
    Springer
    Molecular breeding 5 (1999), S. 209-218 
    Details
    ISSN: 1572-9788
    Keywords: alternative oxidase ; antisense ; male-sterility ; tapetum-specific promoter ; tobacco ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The alternative oxidase of plant mitochondria is the terminal oxidase of the cyanide-insensitive respiratory pathway and is encoded by a nuclear gene. A 1 kb genomic fragment including exon 3 of the alternative oxidase was amplified by PCR from the genome of Arabidopsis thaliana. This fragment was connected to a tapetum-specific promoter in the antisense orientation and then introduced into tobacco. The pollen viability in three transgenic plants ranged from 2% to 60%. The reduced pollen viability cosegregated with the transgene in a selfed progeny. Immunolocalization of alternative oxidase protein in the immature flower bud section indicated that expression of alternative oxidase protein in tapetum of the transgenic plant was much lower than that of the non-transformant. The histological observation and protein gel-blot analysis showed that the development of pollen grains in the transgenic plant did not progress after the degradation of the tapetum, and the amount of alternative oxidase in pollen grains of the transgenic plant became lower than that of the non-transformant. These results suggested that the alternative oxidase activity in the tapetum has a significant effect on the pollen development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009606601521
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Expansive Visibilization of Work: An Activity-Theoretical Perspective (1999)
    Springer
    Computer supported cooperative work 8 (1999), S. 63-93 
    Details
    ISSN: 1573-7551
    Keywords: activity theory ; action ; transformation ; expansive learning ; intervention ; visibilization ; health care ; medical records
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Work is commonly made visible along two dimensions: the linear and the socio-spatial. Both are limited to depicting work in terms of relatively discrete actions. Activity theory introduces the crucial distinction between collective activity systems and individual actions. Expansive visibilization of collective activity systems offers a powerful intervention methodology for dealing with major transformations of work. The linear and the socio-spatial dimensions of work actions are seen in the broader perspective of a third, developmental dimension of work activity. Four steps are identified in a cycle of expansive visibilization, combining activity-level visions and action-level concretizations. The cycle is examined in detail as it unfolded in an intervention study at a children's hospital in Finland. It is concluded that expansive visibilization, driven by contradictions and seeking to reconceptualize the object and motive of work, is not a straightforward process which can be neatly controlled from above. Coherent analytical explanation and goal-setting may come only after the creation and practical implementation of innovative solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008648532192
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    REMI (Restriction Enzyme Mediated Integration) and its Impact on the Isolation of Pathogenicity Genes in Fungi Attacking Plants (1999)
    Springer
    European journal of plant pathology 105 (1999), S. 221-229 
    Details
    ISSN: 1573-8469
    Keywords: mutagenesis ; transformation ; plant disease ; recombination ; plant pathogenic fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Development of molecular techniques for phytopathogenic fungi aims at the identification of fungal genes whose products are essential for successful infection of the host plant. Initial approaches have relied on isolating candidate genes and generating null-mutations by homologous recombination. Unfortunately, the results of this strategy have not been overly successful. This has led to a search for alternatives which allow an unbiased identification of pathogenicity genes. One method, which has proved successful in several systems, is a tagging mutagenesis procedure termed restriction enzyme mediated integration (REMI). In this mini-review we describe this procedure and review its features and results of its use when applied to the identification of fungal genes required for disease development in planta.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008757414036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A mini binary vector series for plant transformation (1999)
    Springer
    Plant molecular biology 40 (1999), S. 711-717 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; Arabidopsis thaliana ; binary vector ; T-DNA ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A streamlined mini binary vector was constructed that is less than 1/2 the size of the pBIN19 backbone (3.5 kb). This was accomplished by eliminating over 5 kb of non-T-DNA sequences from the pBIN19 vector. The vector still retains all the essential elements required for a binary vector. These include a RK2 replication origin, the nptIII gene conferring kanamycin resistance in bacteria, both the right and left T-DNA borders, and a multiple cloning site (MCS) in between the T-DNA borders to facilitate cloning. Due to the reduced size, more unique restriction sites are available in the MCS, thus allowing more versatile cloning. Since the traF region was not included, it is not possible to mobilize this binary vector into Agrobacterium by triparental mating. This problem can be easily resolved by direct transformation. The mini binary vector has been demonstrated to successfully transform Arabidopsis plants. Based on this mini binary vector, a series of binary vectors were constructed for plant transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006201910593
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Wnt Signalling in Mammalian Development and Cancer (1999)
    Springer
    Cancer and metastasis reviews 18 (1999), S. 215-230 
    Details
    ISSN: 1573-7233
    Keywords: transformation ; tumour ; Frizzled ; Dishevelled ; glycogen synthase kinase-3β
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Wnt signalling is involved in a variety of mammalian developmental processes, including cell proliferation, differentiation and epithelial–mesenchymal interactions, through which they contribute to the development of tissues and organs such as the limbs, the brain, the reproductive tract and the kidney. Wnts are secreted ligands that control cell processes via at least two pathways, one of which, the ‘canonical’ Wnt signalling pathway, operates through the cytosolic stabilisation of a transcriptional co-factor, β-catenin. This is achieved by downregulating the activity of a β-catenin turnover complex. Evidence from tumour expression studies, transgenic animals and in vitro experiments suggests that inappropriate activation of the canonical Wnt signalling pathway is a major feature in human neoplasia and that oncogenic activation of this pathway can occur at many levels. Inappropriate expression of the Wnt ligand and Wnt binding proteins have been found in a variety of human tumours. Further downstream, dysregulation of the β-catenin turnover complex, by loss of the Adenomatous Polyposis Coli or Protein Phosphatase 2A proteins, or by activating mutations of β-catenin, has been found in several tumour types, and is believed to be a key step in neoplastic progression. Transcriptional targets of the Wnt pathway include the cellular oncogenes cyclin D1 and c-myc. Activation of the Wnt signalling pathway by various means can therefore be a primary cause in oncogenesis, affecting cell proliferation, morphology and contact inhibition, as well as co-operating with other oncogenes in multistep tumour progression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006369223282
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Institutional transformation at South African universities: Implications for academic staff (1999)
    Springer
    Higher education 38 (1999), S. 275-290 
    Details
    ISSN: 1573-174X
    Keywords: academic staff ; curriculum change ; equity ; governance ; staff development ; student needs ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract In South Africa the restructuring of the higher education system and the transformation of higher education institutions are located within the country's broad political and socio-economic transition to democracy. This paper focuses particularly on institutional transformation, and pays attention to the implications of the process of transformation for academic staff. The following five interlinked and interdependent issues characterizing institutional transformation in South African higher education are identified: democratising the governance structures of institutions increasing access for educationally and financially disadvantaged students restructuring the curriculum focusing on developmental needs in research and community service redressing inequalities in terms of race and gender. Although the overall effect of institutional transformation is experienced rather negatively by many academic staff members, the paper concludes that academics have to be empowered by means of staff development to remain active partners in the transformation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003768229291
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Anaerobic transformation of 1,1,1-trichloroethane by municipal digester sludge (1999)
    Springer
    Biodegradation 10 (1999), S. 297-305 
    Details
    ISSN: 1572-9729
    Keywords: abiotic ; biological ; cell-free extract ; chloroethane ; dechlorination ; 1,1-dichloroethane ; 1,1-dichloroethene ; digester ; methanogenic ; transformation ; 1,1,1-trichloroethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Anaerobic transformations of 1,1,1-trichloroethane (TCA), 1,1-dichloroethane (DCA), and chloroethane (CA) were studied with sludge from a lab-scale, municipal wastewater sludge digester. TCA was biologically transformed to DCA and CA and further to ethane by reductive dechlorination. TCA was also converted to acetic acid and 1,1-dichloroethene (11DCE) by cell-free extract. 11DCE was further biologically converted to ethene. This pathway was confirmed by transformation tests of TCA, DCA and CA, by tests with cell-free extract, and by chloride release during TCA degradation. With cell-free extract, acetic acid accounted for approximately 90% of the TCA transformed; tests with live cells indicate that the fraction of TCA transformed by this pathway decreased with lower biomass. The dechlorination of DCA to CA and CA to ethane was not stoichiometric. A high rate of TCA removal was observed under the experimental conditions. The results indicate that removal of TCA in anaerobic digestion should be complete, but DCA and CA could persist in a normally operating digester.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008336103968
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Urban development in East Germany — specific features of urban transformation processes (1999)
    Springer
    GeoJournal 49 (1999), S. 43-51 
    Details
    ISSN: 1572-9893
    Keywords: housing market ; suburbanisation ; transformation ; urban development ; urban renewal ; East Germany
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract The aim of this paper is to analyse the main characteristics of post-socialist urban development in East Germany, especially the differences compared to urban development in other East and Central European countries. In spite of the many similar problems and processes in urban development, specific features of East Germany are characterised by the rapid growth of suburbia, especially in the first phase of transition, by the proceeding activities of urban renewal and revitalisation, and by a lower level of social polarisation and socio-spatial segregation as compared to other post-socialist countries. Important conditions for urban development in East Germany exist in special support programmes, high subsidies and other financial transfers as well as in engaged planning conceptions of the local authorities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007016912703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    A promoter from sugarcane bacilliform badnavirus drives transgene expression in banana and other monocot and dicot plants (1999)
    Springer
    Plant molecular biology 39 (1999), S. 1221-1230 
    Details
    ISSN: 1573-5028
    Keywords: constitutive expression ; GFP ; GUS ; Musa ; ScBV ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A 1369 bp DNA fragment (Sc) was isolated from a full-length clone of sugarcane bacilliform badnavirus (ScBV) and was shown to have promoter activity in transient expression assays using monocot (banana, maize, millet and sorghum) and dicot plant species (tobacco, sunflower, canola and Nicotiana benthamiana). This promoter was also tested for stable expression in transgenic banana and tobacco plants. These experiments showed that this promoter could drive high-level expression of the β-glucuronidase (GUS) reporter gene in most plant cells. The expression level was comparable to the maize ubiquitin promoter in standardised transient assays in maize. In transgenic banana plants the expression levels were variable for different transgenic lines but was generally comparable with the activities of both the maize ubiquitin promoter and the enhanced cauliflower mosaic virus (CaMV) 35S promoter. The Sc promoter appears to express in a near-constitutive manner in transgenic banana and tobacco plants. The promoter from sugarcane bacilliform virus represents a useful tool for the high-level expression of foreign genes in both monocot and dicot transgenic plants that could be used similarly to the CaMV 35S or maize polyubiquitin promoter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006125229477
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Selectable marker-free transgenic plants without sexual crossing: transient expression of cre recombinase and use of a conditional lethal dominant gene (1999)
    Springer
    Plant molecular biology 40 (1999), S. 223-235 
    Details
    ISSN: 1573-5028
    Keywords: conditional lethal dominant gene ; Cre/loxP ; Nicotiana tabacum ; site-specific recombinase ; transformation ; transient expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic tobacco plants were produced that contained single-copy pART54 T-DNA, with a 35S-uidA gene linked to loxP-flanked kanamycin resistance (nptII) and cytosine deaminase (codA) genes. Retransformation of these plants with pCre1 (containing 35S transcribed cre recombinase and hygromycin (hpt) resistance genes) resulted in excision of the loxP-flanked genes from the genome. Phenotypes of progeny from selfed-retransformed plants confirmed nptII and codA excision and integration of the cre-linked hpt gene. To avoid integration of the hpt gene, and thereby generate plants totally free of marker genes, we attempted to transiently express the cre recombinase. Agrobacterium tumefaciens (pCre1) was cocultivated with leaf discs of two pART54-transformed lines and shoots were regenerated in the absence of hygromycin selection. Nineteen of 773 (0.25%) shoots showed tolerance to 5-fluorocytosine (5-fc) which is converted to the toxic 5-fluorouracil by cytosine deaminase. 5-fc tolerance in six shoots was found to be due to excision of the loxP-flanked region of the pART54 T-DNA. In four of these shoots excision could be attributed to cre expression from integrated pCre1 T-DNA, whereas in two shoots excision appeared to be a consequence of transient cre expression from pCre1 T-DNA molecules which had been transferred to the plant cells but not integrated into the genome. The absence of selectable marker genes was confirmed by the phenotype of the T1 progeny. Therefore, through transient cre expression, marker-free transgenic plants were produced without sexual crossing. This approach could be applicable to the elimination of marker genes from transgenic crops which must be vegetatively propagated to maintain their elite genotype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006184221051
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Optimisation of procedures for microprojectile bombardment of microspore-derived embryos in wheat (1999)
    Springer
    Plant cell, tissue and organ culture 57 (1999), S. 207-210 
    Details
    ISSN: 1573-5044
    Keywords: biolistics ; gene expression ; haploid ; transformation ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using the PDS-1000/He Biolistic® Particle Delivery System, the microprojectile travel distance, rupture disk pressure and DNA/gold particle concentrations were assessed in order to optimise short and longer-term β-glucuronidase reporter gene expression in microspore-derived embryos of wheat. The effects were also evaluated of using sterile filter paper to support explants and treatment with a high osmoticum medium (0.2 M mannitol/0.2 M sorbitol or 0.4 M maltose). In the optimised procedure, wheat microspore-derived embryos (MDEs), were placed on filter paper and incubated on medium containing 0.4 M maltose, for 4 h pre- and 45 h post-bombardment. Five μl pAHC25 (0.75 mg ml-1 in TE buffer) was precipitated onto 25 μl gold particles (60 mg ml-1 in sterile water), using 20 μl spermidine (0.1 M) and 50 μl CaCl2 (2.5 M). The particles were centrifuged and resuspended in 75 μl absolute ethanol prior to the preparation of 6 macrocarriers. A microprojectile travel distance of 70 mm, a rupture pressure of 1300 p.s.i., and a vacuum of 29′′ Hg were employed. Maltose at 0.4 M in the support medium was the most important factor influencing GUS activity in bombarded tissues. GUS activity, 1 day post-bombardment, reached 52 ± 17 GUS-positive foci/MDE (mean ± s.e.m, n=3), with 17 ± 4 foci/MDE at 15 days, giving a 3.0-fold increase (p〈0.05) compared to expression in MDEs bombarded on medium without a high osmoticum treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006384525513
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Recovery of transgenic orchid plants with hygromycin selection by particle bombardment to protocorms (1999)
    Springer
    Plant cell, tissue and organ culture 58 (1999), S. 87-92 
    Details
    ISSN: 1573-5044
    Keywords: ß-glucuronidase ; dendrobium ; hygromycin phosphotransferase ; orchid ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protocorms of orchid (Dendrobium hybrid) were transformed by microprojectile bombardment with a helium-pressured PDS 1000 particle gun. Gold particles coated with plasmid DNA containing ß-glucuronidase (GUS) and hygromycin phosphotransferase (Hpt) marker genes were used. Potentially transformed tissues were identified by active growth on MS medium supplemented with 50mg l-1 hygromycin. After 4–6 months of continuous selection, 15 hygromycin-resistant lines were recovered. Integration of transgenes into the genome of the transformed protocorms and plantlets were confirmed by GUS histochemical assay and Southern blot hybridization. The transgenic protocorms have gone through propagation for more than 8 months and maintained their transgenic characters. These results indicate that we have established a system for orchid transformation in a relatively high frequency and the transgenes are stably expressed in the transgenic plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006334605947
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Isolation of state transition mutants of Chlamydomonas reinhardtii by fluorescence video imaging (1999)
    Springer
    Photosynthesis research 61 (1999), S. 43-51 
    Details
    ISSN: 1573-5079
    Keywords: Chlamydomonas reinhardtii ; LHC II phosphorylation ; mutagenesis ; Photosystem II redox control ; state 2 to state 1 transition ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oxygenic photosynthetic organisms adapt to varying light conditions by changing the distribution of light energy between Photosystem II (PS II) and photosystem I (PS I) during so-called state transitions. To identify the genes involved in this process, we have exploited a simple chlorophyll fluorescence video-imaging technique to screen a library of nuclear mutants of Chlamydomonas reinhardtii for colonies grown on agar plates that are disturbed in their ability to regulate light energy distribution between PS I and PS II. Subsequent modulated fluorescence measurements at room temperature and 77 K fluorescence emission spectra confirmed that 5 mutants (0.025% of total number screened) were defective in state transitions. [32P]orthophosphate phosphorylation experiments in vivo revealed that in one of these mutants, designated stm1, the level of LHC II polypeptide phosphorylation was drastically reduced compared with wild type. Despite WT levels of PS I and PS II, stm1 grew photoautotrophically at reduced rates, compared with WT especially under low light conditions, which is consistent with an important physiological role for state transitions. Our results highlight the feasibility of video imaging in tandem with mutagenesis as a means of identifying the genes involved in controlling state transitions in eukaryotic photosynthetic organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006229308606
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Simple method for plasmid mediated transformation of different Bacillus species (1999)
    Springer
    Biotechnology techniques 13 (1999), S. 337-340 
    Details
    ISSN: 1573-6784
    Keywords: Bacillus ; plasmids ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A simple and easy method for the introduction of plasmid DNA into different species of Bacillus was developed. The method involves the suspension in a transformation buffer of nutrient agar grown cells in their late exponential phase and the addition of unpurified plasmid DNA. Transformants were obtained at a frequency of about 103 to 105 stable transformants per μg of plasmid DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008941007983
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Long-Term Transformation and Redistribution of Potentially Toxic Heavy Metals in Arid-Zone Soils: II. Incubation at the Field Capacity Moisture Content (1999)
    Springer
    Water, air & soil pollution 114 (1999), S. 221-250 
    Details
    ISSN: 1573-2932
    Keywords: arid-zone soils ; field capacity ; fractionation ; heavy metals ; kinetics ; redistribution ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Solid-phase transformation of added Cd, Cu, Cr, Ni, Pb and Zn, in two arid-zone soils incubated in the field capacity moisture regime for one year, were studied. The heavy metals were fractionated into six empirically defined fractions using a selective sequential dissolution (SSD) protocol optimized for arid-zone soils. Each of these fractions was named based on the major soil component targeted for dissolution during the specific SSD step, but it is not assumed that they are mineralogically and chemically totally specific. The transformations of the metals in the two soils incubated at the field capacity regime were compared with those at the moisture saturation regime (Han and Banin, 1997). An initial fast stage of transformation of the soluble metals from the exchangeable (EXC) fraction to the less labile fractions (the carbonate (CARB) fraction for Cd, Pb, Zn, Ni and Cu, and the organic matter (OM) fraction for Cr, and to some extent Cu and Ni) occurred during the fractionation and within one hour after addition. This was followed by a second stage, involving long-term transformation processes of all metals: added Cd was transferred from the EXC into the CARB fraction; added Cr was transferred from the CARB to the OM fraction and Pb was transferred very slowly to the easily reducible oxide (ERO) fraction. Added Cu, Ni and Zn were transferred from the EXC and CARB fractions into the ERO fraction and to some extent OM and RO fractions. In Part I of this series, we reported that during incubation in the saturated moisture regime, Zn and Ni were transferred mainly into the RO and OM fractions. Cadmium, Cr and Pb underwent the same transformation pathways during the slow long-term process, with slightly different rates, in both water regimes. At low levels of addition, the incubated soils moved over one year towards a distribution similar to that of the native soil. At higher levels, the soils still remained removed from the quasi-equilibrium which characterized the native soil, even at the end of one year of incubation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005006801650
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Sorption Kinetics and Transformation of DDT in Sediment (1999)
    Springer
    Water, air & soil pollution 110 (1999), S. 57-66 
    Details
    ISSN: 1573-2932
    Keywords: DDT ; kinetic ; organic pollutant ; sediment ; sorption ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The overall objective of this study was to investigate the sorption kinetics of DDT in sediment under similar experimental conditions employed in corresponding toxicity studies for bentic organisms. A batch of aerated Schoonrewoerdse Wiel sediment, initially spiked with DDT, was sampled over a period of seven days. Concentrations of DDT, DDD and DDE were determined in both the solid and the solution phase in the sediment/water system after separation by centrifugation. It was found that the extractable amount of DDT decreased with increasing contact time. This can partly be explained in terms of transformation of DDT into DDD. Furthermore, the present applied extraction procedure seems to be less effective with increasing contact time, indicating an increase in binding strength of DDT with the sediment material. Finally, on the basis of DDT, DDE and DDD concentrations in both the solid phase and the solution phase, partition coefficients were calculated, which appeared to be independent of the contact time. This points at a very rapid equilibrating between DDT in pore water and in the extractable forms adsorbed at the solid phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005087429581
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Environmental Risk Assessment for Pesticides in the Atmosphere; The Results of an International Workshop (1999)
    Springer
    Water, air & soil pollution 115 (1999), S. 5-19 
    Details
    ISSN: 1573-2932
    Keywords: atmospheric fate ; atmospheric transport ; deposition ; emission ; long-range transport ; pesticides ; registration ; remote area ; risk assessment ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The Health Council of the Netherlands organised an international workshop on the fate of pesticides in the atmosphere and possible approaches for their regulatory environmental risk assessment. Approximately forty experts discussed what is currently known about the atmospheric fate of pesticides and major gaps in our understanding were identified. They favoured a tiered approach for assessing the environmental risks of atmospheric dispersion of these chemicals. In the first tier a pesticide's potential for emission during application, as well as its volatilisation potential should be assessed. Estimates of the former should be based on the application method and the formulation, estimates of the latter on a compound's solubility in water, saturated vapour pressure and octanol/water partition coefficient. Where a pesticide's potential for becoming airborne exceeds critical values, it should be subjected to a more rigorous second tier evaluation which considers its toxicity to organisms in non-target areas. This evaluation can be achieved by calculating and comparing a predicted environmental concentration (PEC) and a predicted no-effect concentration (PNEC). By applying an extra uncertainty factor the PNEC can be provisionally derived from standard toxicity data that is already required for the registration of pesticides. Depending on the distance between the source and the reception area, the PEC can be estimated for remote areas using simple dispersion, trajectory type models and for nearby areas using common dispersion models and standard scenarios of pesticide use. A pesticide's atmospheric transport potential is based on factors such as its reaction rate with OH radicals. It should be used to discriminate between those compounds for which only the risks to nearby ecosystems have to be assessed, and those for which the risks to remote ecosystems also have to be determined. The participants were of the opinion that this approach is, in principle, scientifically feasible, although the remaining uncertainties are substantial. Further field and laboratory research is necessary to gain more reliable estimates of the physico-chemical properties of pesticides, to validate and improve environmental fate models and to validate the applicability of standard toxicity data. This will increase both the accuracy of and our confidence in the outcome of the risk assessment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005238703698
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Evolution of gene transfer in bacteria (1999)
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 1-6 
    Details
    ISSN: 1573-0972
    Keywords: Bacteria ; conjugation ; DNA ; evolution ; gene transfer ; transduction ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The transfer of genetic information by transformation, conjugation and transduction in bacteria occurs frequently in nature. These diverse gene transfer mechanisms in bacteria are the result of evolution and are not linked to reproduction as in eukaryotic organisms. In this review, gene transfer in bacteria will be considered from an evolutionary perspective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008830914223
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Biotransformation of cholesterol by Micrococcus species mediated by plasmid DNA (1999)
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 411-415 
    Details
    ISSN: 1573-0972
    Keywords: Electroporation ; Micrococcus species ; steroid biotransformation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A steroid-biotransforming strain RJ6 was identified as Micrococcus roseus. This bacterium has a 10 kb plasmid pMQV10. Curing mediated through cultivation of the culture with a low concentration (200 ng/ml) of mitomycin C is described. Loss of cholesterol degradation (chol+) and streptomycin resistance (Smr) phenotypes as a consequence of the loss of plasmid indicate the extrachromosomal location of these two genes in this strain. An electroporation procedure was developed for transformation of cured strain of Micrococcus (RJC6) by plasmids. Frequency of greater than 105 transformants/μg DNA was achieved, which is 100-fold higher than the standard transformation procedure that yielded 5.3×103 transformants/μg DNA in the same strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008990910303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Airflow and temperature distribution in two-dimensional drying bins (1999)
    Springer
    Journal of engineering mathematics 36 (1999), S. 241-254 
    Details
    ISSN: 1573-2703
    Keywords: flows in porous media ; transformation ; heat transfer ; drying bins ; conformal mapping.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Technology
    Notes: Abstract The design of a drying or cooling store aims to provide an even airflow distribution, when aerated, for preservation purposes. The airflow in some curved bottom bins are studied in this paper. The flow is modelled, using Darcy's law. A generalized Schwarz-Christoffel transformation is employed to reduce the problem of computing streamlines and isobars of airflow to solving a single nonlinear equation for the flow angle along the wall. Corresponding to different bin shapes, a few computed streamlines and isobars of airflow are presented, showing the effect of changing bottom geometries on the air flow. Heat transfer in such bins is also investigated. Based on an analysis of the far field of airflow, finite-height bins are considered. Analytical solutions of the heat conduction equation in terms of streamlines and isobars are obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004488010532
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Changes in morphology, cytoskeleton, and substrate dependence of proliferation after transfection of immortalized rat embryonic fibroblasts with E7 gene of type 16 human papilloma virus (1999)
    Springer
    Bulletin of experimental biology and medicine 127 (1999), S. 99-102 
    Details
    ISSN: 1573-8221
    Keywords: human papilloma virus ; transformation ; actin ; fibronectin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Transfection of rat embryonic fibroblasts with E7 gene of type 16 human papilloma virus changed the cytoskeleton and cell-cell and cell-matrix interactions in two clones of transformed cells. Cell morphology and substrate-dependent proliferation were also changed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02432813
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    pBIN20: An Improved Binary Vector for shape Agrobacterium-mediated Transformation (1998)
    Springer
    Plant molecular biology reporter 16 (1998), S. 129-131 
    Details
    ISSN: 1572-9818
    Keywords: Agrobacterium tumefaciens ; binary vector ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report the construction of a binary vector for Agrobacterium tumefaciens-mediated transformation, pBIN20, which contains a superlinker region located between the left and right Ti border sequences. This vector, derived from pBI121, simplifies the cloning of plant expression cassettes and has been used in our laboratory to create lines of transgenic BY-2 tobacco cells. This new vector contains more than 20 unique restriction sites as well as the nptII selectable marker gene within the Ti-DNA borders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007444100898
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Space-time estimation of grid-cell hourly ozone levels for assessment of a deterministic model (1998)
    Springer
    Environmental and ecological statistics 5 (1998), S. 197-222 
    Details
    ISSN: 1573-3009
    Keywords: kriging ; non-separable space-time correlation ; spatial scale ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We present an approach to estimate hourly grid-cell surface ozone concentrations based on observations from point monitoring sites in space, for comparison with grid-based results from the SARMAP photochemical air-quality model for a region of northern California. Statistical estimation is carried out on a transformed (square root) scale, followed by back-transforming to the original scale of ozone in parts per billion, adjusting for bias and variance. We estimate a spatially-varying diurnal mean structure and a non-separable space-time correlation structure on the transformed scale. Temporal pre-whitening is followed by modelling of a spatially non-stationary, diurnally-varying spatial correlation structure using a spatial deformation approach. Comparisons of SARMAP model results with the estimated grid-cell ozone levels are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009663518685
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Genetic transformation and regeneration of mature tissues of woody fruit plants bypassing the juvenile stage (1998)
    Springer
    Transgenic research 7 (1998), S. 51-59 
    Details
    ISSN: 1573-9368
    Keywords: sweet orange ; Citrus ; woody ; transformation ; Agrobacterium ; mature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regeneration and transformation systems from mature plant material of woody fruit species have to be achieved as a necessary requirement for the introduction of useful genes into specific cultivars and the rapid evaluation of resulting horticultural traits. We report here, for the first time, a procedure for genetic transformation and regeneration of mature tissues of woody plants that overcomes the long juvenile periods and high heterozygosity that are characteristic of most of these species. An improved regeneration frequency from mature explants was obtained by invigoration of the plant material through grafting of mature buds on juvenile seedlings. Co-cultivation of the explants in feederplates after inoculation with Agrobacterium tumefaciens resulted in enhanced transformation frequencies. Furthermore, in vitro shoot-tip grafting of the regenerated mature shoots on seedling rootstocks provided a rapid and efficient system for plant production. Citrus is the most extensivel y grown fruit crop worldwide and sweet orange (Citrus sinensis L. Osbeck) accounts for approximately 70% of the Citrus total production. Mature transgenic sweet orange plants have been obtained, which flowered and bore fruit in 14 months
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008855922283
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    An efficient protocol for sugarcane (Saccharum spp. L.) transformation mediated by Agrobacterium tumefaciens (1998)
    Springer
    Transgenic research 7 (1998), S. 213-222 
    Details
    ISSN: 1573-9368
    Keywords: Saccharum ; Agrobacterium ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This is the first successful report of the recovery of morphologically normal transgenic sugarcane plants from co-cultivation of calluses with Agrobacterium tumefaciens. Transformation frequencies (total of transgenic plants/number of cell clusters) were between 9.4 × 10−3 and 1.15 × 10−2. In our experiments, both LBA4404 (pTOK233) and EHA101 (pMTCA3IG), carrying a super-binary vector or supervirulent strain, respectively, were successful for sugarcane transformation. We found that three main factors: (1) the use of young regenerable calluses as target explants; (2) induction and/or improvement of the A. tumefaciens virulence system with sugarcane cell cultures and (3) pre-induction of organogenesis or somatic-embryogenesis-like sexual embryos, seem to be crucial in order to increase the cells competence for T-DNA transfer process. Patterns generated by Southern hybridization confirmed that T-DNAs were randomly integrated into sugarcane genome without th e persistence of A. tumefaciens in the transgenic plants
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008845114531
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    An Efficient Rice Transformation System Utilizing Mature Seed-derived Explants and a Portable, Inexpensive Particle Bombardment Device (1998)
    Springer
    Transgenic research 7 (1998), S. 289-294 
    Details
    ISSN: 1573-9368
    Keywords: Oryza sativa ; particle bombardment ; transformation ; transgenic rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We developed a practical and efficient gene transfer system for indica rice utilizing mature-seed derived explants and a simple bombardment device which uses compressed helium for accelerating DNA-coated metal particles. Unlike instruments which have been described in the literature previously, this new bombardment device, which is an improvement of the particle inflow concept, does not require vacuum. This attribute simplifies the transformation procedure significantly and it makes rice transformation technology accessible to laboratories which may not have the resources to invest in more expensive particle bombardment instruments. We determined experimentally that we could recover transgenic rice plants utilizing three different particle bombardment instruments at comparable frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008870012568
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Molecular and cellular evidence of chimaeric tissues in primary transgenics and elimination of chimaerism through improved selection protocols (1998)
    Springer
    Transgenic research 7 (1998), S. 123-129 
    Details
    ISSN: 1573-9368
    Keywords: chimaera ; iterative culture ; regeneration ; strawberry ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic plants of strawberry cultivar Totem were developed by Agrobacterium-mediated transformation using a plasmid vector containing gus and nptII genes. Parallel experiments were carried out with and without repeated subculturing (iterative cultures) for generation of transgenic shoots on selection medium. The selection levels in the non-iterative pathway were kept constant, while in the iterative protocol, stepwise increase of selection pressure was applied at different stages of tissue growth. Rooted transgenic plants obtained via both protocols were outplanted in soil. Random leaf samples of greenhouse-grown transgenics were analysed for the presence of gus gene sequences by Southern hybridization as well as gus expression on leaf and petiole tissues by X-Gluc histological assay. Random leaf samples analysed from individual transgenic events developed under iterative culture were positive for the gus insert as verified by Southern analysis confirming the presence of transgenes and lack of chimaeras. Leaf samples of the transgenic events from the non-iterative protocol were either positive or negative on Southern analysis indicating the chimaeric nature of the transgenic plants. The absence of gus sequences in the transgenic plants grown under the non-iterative protocol reinforced the necessity of iterative cultures along with stepwise increase in selection levels for generating non-chimaeric transgenics in strawberry. The gus expression was highly variable, irrespective of the iterative or non-iterative protocol used for transformation. We conclude that strawberry is highly prone to develop chimaeric transgenics if derived from primary regenerants and that the iterative culture technique effectively converts chimaeras to pure line transgenic plants
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008872425917
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Transformation and Anomie: Problems of Quality of Life in Bulgaria (1998)
    Springer
    Social indicators research 43 (1998), S. 197-209 
    Details
    ISSN: 1573-0921
    Keywords: transformation ; anomie ; social integration ; state ; quality of life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology
    Notes: Abstract The weakening of social integration and anomie are unavoidable in the transformation of societies. The effect is a decrease of quality of life accompanied by disenchantments, aggressiveness and escapism. In some countries in Eastern Europe like Bulgaria the anomie effects of transformation became particularly strong. The major reason is the political instability. The dissolution of the previous state-centered over-integration of society developed into a dissolution of major mechanisms of political integration. The prospects for improvement of quality of life are focused on the balance of economic, political and cultural re-integration of Bulgarian society.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006895413626
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Introduction of the cDNA for shape Arabidopsis glycerol-3-phosphate acyltransferase (GPAT) confers unsaturation of fatty acids and chilling tolerance of photosynthesis on rice (1998)
    Springer
    Molecular breeding 4 (1998), S. 269-275 
    Details
    ISSN: 1572-9788
    Keywords: glycerol-3-phosphate acyltransferase ; phosphatidylglycerol ; chilling tolerance ; transformation ; fatty acid composition ; Oryza sativa L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The chilling sensitivity of several plant species is closely correlated with the levels of unsaturation of fatty acids in the phosphatidylglycerol (PG) of chloroplast membranes. Plants with a high proportion of unsaturated fatty acids, such as Arabidopsis thaliana, are resistant to chilling, whereas species like squash with only a low proportion are rather sensitive to chilling. The glycerol-3-phosphate O-acyltransferase (GPAT) enzyme of chloroplasts plays an important role in determining the levels of PG fatty acid desaturation. A cDNA for oleate-selective GPAT of Arabidopsis under the control of a maize Ubiquitin promoter was introduced into rice (Oryza sativa L.) using the Agrobacterium-mediated gene transfer method. The levels of unsaturated fatty acids in the phosphatidylglycerol of transformed rice leaves were found to be 28% higher than that of untransformed controls. The net photosynthetic rate of leaves of transformed rice plants was 20% higher than that of the wild type at 17°C. Thus, introduction of cDNA for the Arabidopsis GPAT causes greater unsaturation of fatty acids and confers chilling tolerance of photosynthesis on rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009671231614
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Transformation of Nicotiana tabacum with a native cry1Ia5 gene confers complete protection against Heliothis armigera (1998)
    Springer
    Molecular breeding 4 (1998), S. 473-478 
    Details
    ISSN: 1572-9788
    Keywords: Bt genes ; transformation ; protection against insects ; cry1Ia5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A cry1Ia5 insecticidal toxin coding gene has been cloned from an Indian isolate of Bacillus thuringiensis. Sequence analyses of the cry1Ia5 gene revealed the absence of potential polyadenylation signal sequences thus making it a suitable candidate for expression in plants without extensive modification. This possibility was examined by subcloning the cry1Ia5 gene into a plant expression vector and then transferring it to Nicotiana tabacum through Agrobacterium-mediated transformation. Our results demonstrate that N. tabacum with a stably integrated native cry1Ia5 gene afforded complete protection against predation by Heliothis armigera. Forty three percent of the transgenic plants displayed a high level of protection against insect predation. The protection obtained in transgenic plants with the cry1Ia5 gene was comparable to that obtained with the synthetically modified cry1A(b) or cry1A(c) genes. The results demonstrate that novel insecticidal genes already exist in nature that do not require extensive modifications for efficient expression in plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009696027993
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    An antisense chalcone synthase cDNA leads to novel colour patterns in lisianthus (Eustoma grandiflorum) flowers (1998)
    Springer
    Molecular breeding 4 (1998), S. 59-66 
    Details
    ISSN: 1572-9788
    Keywords: antisense ; chalcone synthase ; flower colour ; lisianthus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three cultivars of lisianthus (Eustoma grandiflorum (Grise.)) were transformed with a homologous antisense CHS cDNA via Agrobacterium-mediated transformation. Over 50% of the transgenics derived from the purple flowering lines exhibited an altered flower colour pattern ranging from small streaks of white on the wild-type purple background through to completely white flowers. A significant portion of the transgenic lines showed unstable phenotypes. Northern and biochemical analysis showed that the altered flower patterns were associated with a loss of CHS gene transcript and a corresponding loss of CHS enzyme activity. In the white flowering line the level of total flavonoids was reduced to ca. 2.0% of the wild-type level. Some of the transgenic plants also exhibited alterations in flower form such as the formation of frilled petal tips and reduced flower opening. Several of the new patterned lines are being evaluated for stability and possible commercial release.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009621903402
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Transgenic elite Indica rice varieties, resistant to Xanthomonas oryzae pv. oryzae (1998)
    Springer
    Molecular breeding 4 (1998), S. 551-558 
    Details
    ISSN: 1572-9788
    Keywords: Indica rice ; cell suspension ; transformation ; Xa21 ; bacterial leaf blight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The agronomically important Indica (group 1) rice varieties IR64, IR72, hybrid restorer line Minghui 63, and BG90-2 were co-transformed by microbombardment of embryogenic suspensions with plasmids that contain the Xa21 gene which confers resistance to Xanthomonas oryzae pv. oryzae and the hph gene for resistance to hygromycin B. Six of the 55 transgenic R0 plant lines containing the Xa21 gene displayed high levels of resistance to the pathogen, and no partial resistance was observed. The trait was stably inherited in subsequent generations, and transgenic plants are currently in field tests. The ability to transfer agronomically important genes into elite Indica rice varieties demonstrates the applicability of genetic engineering for the agronomic improvement of rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009601520901
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Agrobacterium tumefaciens-mediated transformation of cauliflower, Brassica oleracea var. botrytis (1998)
    Springer
    Molecular breeding 4 (1998), S. 531-541 
    Details
    ISSN: 1572-9788
    Keywords: Agrobacterium ; Brassica oleracea ; cauliflower ; regeneration ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have developed an efficient and simpler method for genetic transformation and regeneration of cauliflower, Brassica oleracea var. botrytis plants. Explants from 4-day old seedlings were inoculated and cocultivated with Agrobacterium tumefaciens strain LBA4404 harbouring a binary vector with the neomycin phosphotransferase-II gene under the regulatory control of nopaline synthase promoter and terminator sequences, permitting transformed shoots to be selected on kanamycin containing medium. After three months rooted transformed plantlets were successfully transferred and grown under glasshouse conditions. Higher numbers of transformed plants were obtained from cotyledon than hypocotyl explants, presumably indicating cotyledons of cauliflower are more amenable to genetic transformation. Integration and expression of the introduced transgene were analysed by DNA gel blot and PCR analysis and NPT-II expression assay. Factors influencing transformation efficiency include explant age, concentration of bacterium used for infection, duration of infection and cocultivation with Agrobacterium. Transgenic plants of three commercial genotypes of cauliflower were produced using this method. We also show that introduction of antisense Bcp1 (pollen-specific gene) linked to a pollen-specific promoter (Lat52) resulted in the expected sterility of 50% pollen carrying this transgenic construct.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009658614579
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Composition of endogenous alleles can influence the level of antisense inhibition of granule-bound starch synthase gene expression in tetraploid potato plants (1998)
    Springer
    Molecular breeding 4 (1998), S. 343-358 
    Details
    ISSN: 1572-9788
    Keywords: amylose ; antisense RNA ; endogenous allele ; Solanum tuberosum ; T-DNA insertion ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The T-DNA composition was analysed of twelve potato genotypes obtained after transforming a tetraploid cultivar with an antisense granule-bound starch synthase (GBSSI) gene. In five transformants (labelled TB50 nos.) the antisense GBSSI gene was driven by the CaMV 35S promoter, while in the remaining seven (labelled TBK50 nos.) the GBSSI promoter was used. In these twelve transformants the antisense effect on amylose production in potato tuber starch ranged from complete suppression to no discernible inhibition, and the number of T-DNA insertions ranged from one to at least fifteen. The antisense effect of individual T-DNA loci in progeny of these transformants was studied. Progeny containing a single T-DNA showed no inhibition of GBSSI activity. Only multiple, linked T-DNA insertions resulted in substantial antisense inhibition. T-DNA fragments present in duplex in selfed progeny resulted in a larger antisense effect than that in the parent (which contained the T-DNA insertions in simplex). Furthermore, the antisense effects of some T-DNA-containing linkage groups were influenced by the composition of endogenous GBSSI alleles. For practical breeding this implies that (1) the efficiency of obtaining primary potato transformants showing complete inhibition of GBSSI gene expression by antisense RNA is genotype-dependent, and (2) many transformants have to be produced per genotype to be able to select plants with maximum suppression of GBSSI and a minimum number of T-DNA loci.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009697725778
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Investigation of Agrobacterium-mediated transformation of apple using green fluorescent protein: high transient expression and low stable transformation suggest that factors other than T-DNA transfer are rate-limiting (1998)
    Springer
    Plant molecular biology 37 (1998), S. 549-559 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; apple ; GFP ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To investigate early events of Agrobacterium-mediated transformation of apple cultivars, a synthetic green fluorescent protein gene (SGFP) was used as a highly sensitive, vital reporter gene. Leaf explants from four apple cultivars (‘Delicious’, ‘Golden Delicious’, ‘Royal Gala’ and ‘Greensleeves’) were infected with Agrobacterium EHA101 harboring plasmid pDM96.0501. Fluorescence microscopy indicated that SGFP expression was first detected 48 h after infection and quantitative analysis revealed a high T-DNA transfer rate. Plant cells with stably incorporated T-DNA exhibited cell division and developed transgenic calli, followed by formation of transgenic shoots at low frequencies. The detection of SGFP expression with an epifluorescence stereomicroscope confirmed the effectiveness of SGFP as a reporter gene for detection of very early transformation events and for screening of putative transformants. The efficiency of the transformation and regeneration process decreased ca. 10000-fold from Agrobacterium infection to transgenic shoot regeneration, suggesting that factors other than Agrobacterium interaction and T-DNA transfer are rate-limiting steps in Agrobacterium-mediated transformation of apple.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006041313209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Molecular wheat breeding by direct gene transfer (1998)
    Springer
    Euphytica 100 (1998), S. 219-223 
    Details
    ISSN: 1573-5060
    Keywords: cereals ; wheat ; transformation ; genetic modification ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A method for efficient genetic transformation of wheat has been developed using immature embryos as targets for microprojectile-mediated gene transfer and a helium driven particle delivery system. Screening and selection of transgenic cells, somatic embryos and regenerated plants are performed with the gus-gene and the phosphinothricin acetyl transferase (bar) gene coding for Basta-resistance as the selectable marker. On average, one fertile transgenic plant can be obtained from about 100 microprojectile treated, immature embryos. The number of integrated copies of the transferred gene ranges from 1 up to about 10. Stable integrated genes are inherited in most of the transgenic lines in a normal mendelian fashion segregating 3:1 in the F2. Homozygous, as well as heterozygous, lines have been followed and analysed genetically at the molecular level and up to F5. Apart from normal stable gene expression, examples have also been found which showed a loss of gene activity or unexpected segregation pattern. For applied aspects, different genes are transferred aiming for improved disease resistance, modification of quality, or other characteristics. First results from these transgenic lines are reported, and problems still existing with the production of stable transgenic wheat lines are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018356223333
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Irregular patterns of transgene silencing in allohexaploid oat (1998)
    Springer
    Plant molecular biology 38 (1998), S. 597-607 
    Details
    ISSN: 1573-5028
    Keywords: transgene silencing ; epigenetics ; transgene expression ; transgenic plants ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An irregular pattern of transgene silencing was revealed in expression and inheritance studies conducted over multiple generations following transgene introduction by microprojectile bombardment of allohexaploid cultivated oat (Avena sativa L.). Expression of two transgenes, bar and uidA, delivered on the same plasmid was investigated in 23 transgenic oat lines. Twenty-one transgenic lines, each derived from an independently selected transformed tissue culture, showed expression of both bar and uidA while two lines expressed only bar. The relationship of the transgenic phenotypes to the presence of the transgenes in the study was determined using (1) phenotypic scoring combined with Southern blot analyses of progeny, (2) coexpression of the two transgenic phenotypes since the two transgenes always cosegregated, and (3) reactivation of a transgenic phenotype in self-pollinated progenies of transgenic plants that did not exhibit a transgenic phenotype. Transgene silencing was observed in 19 of the 23 transgenic lines and resulted in distorted segregation of transgenic phenotypes in 10 lines. Silencing and inheritance distortions were irregular and unpredictable. They were often reversible in a subsequent generation of self-pollinated progeny and abnormally segregating progenies were as likely to trace back to parents that exhibited normal segregation in a previous generation as to parents showing segregation distortions. Possible causes of the irregular patterns of transgene silencing are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006090731414
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    The insulin-like growth factors and breast cancer — revisited (1998)
    Springer
    Breast cancer research and treatment 47 (1998), S. 197-199 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; insulin-like growth factor system ; IGF-I receptor ; IGF-II receptor ; binding proteins ; prognosis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In 1992, a special issue of Breast Cancer Research and Treatment was devoted to the insulin-like growth factors and breast cancer. In that issue, identification of the key components of the IGF system was reviewed and their potential role in breast cancer growth was described. In this issue, we revisit the IGF system with particular attention to data that further supports their role in the growth regulation of breast cancer. Several new facets of the IGF system are described, and several laboratories have more clearly defined how each individual component of the IGF system may influence breast cancer biology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005938615798
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Genetic transformation of astaxanthin mutants of Phaffia rhodozyma (1998)
    Springer
    Antonie van Leeuwenhoek 73 (1998), S. 147-153 
    Details
    ISSN: 1572-9699
    Keywords: transformation ; plasmid integration ; Phaffia rhodozyma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stable red astaxanthin-producing transformants were obtained after genetic transformation of two Phaffia rhodozyma mutants. A yellow mutant, accumulating β-carotene, and an albino mutant, accumulating phytoene, from P. rhodozyma were transformed using a genomic library of wild-type strain UCD 67-385 in the pBluescript vector. Hybridization assays, using the pBluescript DNA as a radioactive probe, indicate integration of vector sequences into the genome of the transformants. Transformants DNA was digested with restriction endonucleases, ligated with T4 DNA ligase and then used to transform E. coli. Ampicillin resistant plasmids, containing 0.1, 0.2, and 2.5 kb DNA inserts of P. rhodozyma, were rescued from the yeast red transformants. The molecular analysis indicate that transformation has occurred by an integration event of donor DNA into the genome of the host strains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1000602110765
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Double transformation at the eastern border of the EU: the case of the Euroregion pro Europa Viadrina (1998)
    Springer
    GeoJournal 44 (1998), S. 215-224 
    Details
    ISSN: 1572-9893
    Keywords: cross-border region ; transformation ; regional economic development ; Poland ; Germany
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract One of the major means to foster European integration is the establishment of border spanning regions (‘Euroregions’). This is particularly important on the Eastern borders of the EU, e.g. in Eastern Germany. There, however, a double transformation to post-socialist society is taking place, both inside and outside the EU. Tensions arise between objectives on local and higher political levels, intensified by totally different economic structures and access to EU funds on both sides of the border. This is particularly true for the case of the emerging Euroregion Viadrina. Problems in preserving old industrialised localities in East Germany (e.g. steel) and attempts to resurrect the urban fair place Frankfurt/Oder, clash with transition in agriculture and consumer industries and with new concepts in tourism development and environmental protection in the Polish border zone. In region building, political, economic and ideological goals compete with each other. Local initiatives and higher political governance may both support and hamper each other. The same holds true for the interdependence of cultural integration and economic development. The paper concludes that regional economic development can only be expected if, via the building of the Euroregion, the interplay of these factors leads to compromise and harmonization between the different parties involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006818426821
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Transformation of a border region: dispersed agricultural communities in Brasov County, Romania (1998)
    Springer
    GeoJournal 46 (1998), S. 305-317 
    Details
    ISSN: 1572-9893
    Keywords: agriculture ; border region ; communities ; commuting ; conservation ; Romania ; tourism ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract A most distinctive feature of the settlement pattern of the Brasov area is the extreme dispersal of mixed farming encountered in the western extreme of the county to the north and south of Zarnesti: the Bran and Poiana Marului areas. Here a system of peasant subsistence farming developed in a political borderland between the Habsburg and Ottoman Empires. Despite feudal pressures, the peasantry took all available opportunities to extend their independence including elaborate transhumance systems. And after seeing transfrontier commerce as a source of plunder, in the tradition of Balkan highway robbery within relatively unregulated spaces, the peasantry has profited through employment in factories, particularly during the communist period. However, the current recession in manufacturing is throwing the rural population back on limited land resources. Although farming assumes an important subsistence role which contributes to stability, the long-term survival of these communities will depend on new sources of income. Rural tourism has considerable potential and a promising start has been made in Bran. There are, however, constraints on the further development of the business and great attention will have to be given to the conservation of the environment in both the Bucegi Mountains and the Piatra Craiului where national park status is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006984906613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    The non-agricultural economy in post-socialist rural Romania: The insights and perceptions of national, regional and local institutions (1998)
    Springer
    GeoJournal 46 (1998), S. 199-205 
    Details
    ISSN: 1572-9893
    Keywords: chamber of commerce ; economy ; experts ; institutions ; local government ; Romania ; rural ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract This study evaluates some aspects of the socio-economic transformation of rural Romania with reference to the views of representative organisations (at national, regional and local levels) and other experts. Interviews conducted in ten communes of nine Romanian counties (‘judete’) focus attention on the advantages and disadvantages of system change experienced since 1989; the most important problems and constraints for future socio-economic change; and appropriate policies and perspectives for development in the immediate future. Wherever appropriate the claims of interviewees are substantiated through reference to statistics, drawn in many cases from Chambers of Commerce & Industry (CCI). Local level representatives presented much more negative views on recent change than their national and regional level counterparts, but all agreed on the crucial problem of capital shortage. Thus while specific programmes to assist rural areas are justified, they cannot fully succeed until the national economy is able to grow more rapidly and attract greater foreign investment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006947932112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Rural diversification and socio-economic transformation in Croatia (1998)
    Springer
    GeoJournal 46 (1998), S. 263-269 
    Details
    ISSN: 1572-9893
    Keywords: Croatia ; decentralisation ; diversification ; industry ; innovation ; rural ; transformation ; urbanisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Rural diversification in Croatia is well advanced because many rural families have been able to find work in secondary and tertiary activities without the need to migrate to the towns. Many rural settlements have now attained an urban character although there are regional variations, including a contrast between the continental zone with a relatively high level of commitment to agriculture and the coastal areas, with pronounced ‘deagrarisation’ where the ports and tourist resorts are well developed and the natural resource conditions for agriculture are poor. These variations are examined at the municipality level with reference to two key indicators: the share of nonagricultural population and the share of workers in the total active population. Four categories of socio-economic transformation are recognised: more urbanised, urbanised, less urbanised and rural. The main regional differences between the continental and coastal areas are confirmed with the latter showing a relatively high level of socio-economic transformation through the prominence of more highly urbanised municipalities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006976704796
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Induction of a virulence response in Agrobacterium tumefaciens by exudates of Pinus pinea cotyledons (1998)
    Springer
    Plant cell, tissue and organ culture 55 (1998), S. 175-181 
    Details
    ISSN: 1573-5044
    Keywords: Conifer ; transformation ; virulence genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As a preliminary step in efforts to develop a successful protocol for Agrobacterium-mediated transformation of cotyledonary explants of Pinus pinea L. embryos, we tested the ability of embrionary exudates of this species to induce the expression of the virulence genes virA, virB, virC, virD, virE and virG in Agrobacterium tumefaciens containing vir: lacZ fusion constructs. The results obtained in the vir induction assay indicated the absence of bactericidal or bacteriostatic plant compounds affecting A. tumefaciens growth, and showed that cotyledonary and embrionary exudates of P. pinea are able to induce all virulence genes studied, except virG. The data suggest that A. tumefaciens can be used for gene transfer into this important forest and fruit species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006295622061
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    The sugarcane bacilliform badnavirus promoter is active in both monocots and dicots (1998)
    Springer
    Plant molecular biology 38 (1998), S. 347-356 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; Avena sativa ; badnavirus promoter ; constitutive and vascular expression ; GUS staining ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regions of the sugarcane bacilliform badnavirus genome were tested for promoter activity. The genomic region spanning nucleotides 5999–7420 was shown to possess promoter activity as exemplified by its ability to drive the expression of the coding region of the uidA gene of Escherichia coli, in both Avena sativa and Arabidopsis thaliana. In A. sativa, the promoter was active in all organs examined and, with the exception of the anthers where the expression was localized, this activity was constitutive. In A. thaliana, the promoter activity was constitutive in the rosette leaf, stem, stamen, and root and limited primarily to vascular tissue in the sepal and the silique. The transgene was inherited and active in progeny plants of both A. sativa and A. thaliana.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006075415686
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    The xylose isomerase gene from Thermoanaerobacterium thermosulfurogenes allows effective selection of transgenic plant cells using D-xylose as the selection agent (1998)
    Springer
    Plant molecular biology 37 (1998), S. 287-296 
    Details
    ISSN: 1573-5028
    Keywords: plants ; positive selection ; selectable marker ; Thermoanaerobacterium thermosulfurogenes ; transformation ; xylose isomerase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The xylose isomerase gene (xylA) from Thermoanaerobacterium thermosulfurogenes (formerly Clostridium thermosulfurogenes) has been expressed in three plant species (potato, tobacco, and tomato) and transgenic plants have been selected on xylose-containing medium. The xylose isomerase gene was transferred to the target plant by Agrobacterium-mediated transformation. The xylose isomerase gene was expressed using the enhanced cauliflower mosaic virus (CaMV) 35S promoter and the Ω′ translation enhancer sequence from tobacco mosaic virus. Unoptimized selection studies showed that, in potato and tomato, the xylose isomerase selection was more efficient than the established kanamycin resistance selection, whereas in tobacco the opposite was observed. Efficiency may be increased by optimization. The xylose isomerase system enables the transgenic cells to utilize xylose as a carbohydrate source. It is an example of a positive selection system because transgenic cells proliferate while non-transgenic cells are starved but still survive. This contrasts to antibiotic or herbicide resistance where transgenic cells survive on a selective medium but non-transgenic cells are killed. The results give access to a new selection method which is devoid of the disadvantages of antibiotic or herbicide selection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005910417789
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Genetic transformation of Pseudomonas oleovorans by electroporation (1998)
    Springer
    Biotechnology techniques 12 (1998), S. 829-832 
    Details
    ISSN: 1573-6784
    Keywords: Pseudomonas oleovorans ; electroporation ; transformation ; poly(β-hydroxyalkanoate) ; alkane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract An electroporation procedure for the transformation of Pseudomonas oleovorans was developed using a model plasmid, pCN51. The optimal electrotransformation was achieved with cells harvested at 45 to 60 min of growth and concentrated to a cell density of 5 OD600nm, plasmid concentration of 6 μg per 100 μl of cell suspension, and a 0.1-cm gap-width cuvette. Electroporation was performed at the settings of 250 ω, 25μF and 2.5 kV. Transformation yields in the order of 103 colony-forming-unit per electroporation sample were obtained. This is a first report of the electroporation of the commercially valuable bacterium Ps. oleovorans. © Rapid Science Ltd. 1998
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008881121726
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Transformation of the cationic growing center of poly(tetrahydrofuran) into an anionic one by bis(pentamethylcyclopentadienyl)samarium (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2209-2214 
    Details
    ISSN: 0887-624X
    Keywords: cationic polymerization ; anionic polymerization ; transformation ; samarium ; block copolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transformation of the cationic growing center of living poly(tetrahydrofuran) [poly(THF)] into an anionic one was achieved in high efficiency (62%) by the end-capping of living poly(THF) with potassium iodide followed by the reduction with bis(pentamethylcyclopentadienyl)samarium (Cp*2Sm), whereas the direct reduction with Cp*2Sm without the end-capping resulted in the formation of poly(THF) with pentamethylcyclopentadienyl group at the terminal. The increase in the molecular weight of poly(THF) after the reduction was observed, which indicates the presence of the dimerization of poly(THF) during the reduction. The polymerization of a variety of electrophilic monomers including δ-valerolactone, 2-oxo-1,3-dioxane, and alkyl methacrylates with the macroanion provided good yields of the corresponding block copolymers consisting of both cationically and anionically polymerizable monomers. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2209-2214, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 55
    Electronic Resource
    Electronic Resource
    Analysis of mannose selection used for transformation of sugar beet (1998)
    Springer
    Molecular breeding 4 (1998), S. 111-117 
    Details
    ISSN: 1572-9788
    Keywords: Beta vulgaris ; mannose selection ; phosphomannose isomerase ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Various factors affecting mannose selection for the production of transgenic plants were studied using Agrobacterium tumefaciens-mediated transformation of sugar beet (Beta vulgaris L.) cotyledonary explants. The selection system is based on the Escherichia coli phosphomannose isomerase (PMI) gene as selectable gene and mannose as selective agent. Transformation frequencies were about 10-fold higher than for kanamycin selection but were only obtained at low selection pressures (1.0–1.5 g/l mannose) where 20–30% of the explants produced shoots. The non-transgenic shoots were eliminated during the selection procedure by a stepwise increase in the mannose concentration up to 10 g/l. Analysis of the transformed shoots showed that the PMI activity varied from 2.4 mU/mg to 350 mU/mg but the expression level was independent of the selection pressure. Complete resistance to mannose of transformed shoots was observed already at low PMI activities (7.5 mU/mg). Genomic DNA blot analysis confirmed the presence of the PMI gene in all transformants analysed. The possible mode of action of mannose selection compared to other selection methods is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009633809610
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    The Menschutkin reaction of benzyl p-toluenesulfonates with N,N-dimethylanilines. Evidence for the duality of SN1 and SN2 mechanisms (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 254-260 
    Details
    ISSN: 0894-3230
    Keywords: Menschutkin reaction ; duality of SN1, SN2 mechanisms ; benzyl tosylates ; Yukawa-Tsuno equation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rate data for the Menschutkin reaction between strongly activated Z-substituted benzyl p-toluenesulfonates and Y-substituted N,N-dimethylanilines in acetonitrile at 35 °C fit the equation, kobs  =  k1 + k2 [DMA], which is consistent with concurrent first- and second-order processes. The k1 and k2 values for each substrate were separated based on the above equation. The SN1 rate constant, k1, is unaffected by the nature of the nucleophile, whereas the SN2 rate constant, k2, increased with the electron-donating substituent of the N,N-dimethylaniline. The substituent effect on the k1 values is linearly correlated by the Yukawa-Tsuno equation with ρ  =  -5.2 and r  =  1.3. The unimolecular reaction can be regarded as a classical SN1 mechanism. In contrast, that on the k2 values shows an upward curvature when analyzed by the Brown σ+ treatment. These results are ascribed to the simultaneous and independent occurrence of SN1 and SN2 mechanisms in the present Menschutkin reaction. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 57
    Electronic Resource
    Electronic Resource
    Editorial (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 231-231 
    Details
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: No Abstract
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 58
    Electronic Resource
    Electronic Resource
    Solvent effects on infrared spectroscopic and calorimetric characteristics of aliphatic ketones in binary solvent mixtures (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 283-289 
    Details
    ISSN: 0894-3230
    Keywords: calorimetry ; IR spectra ; ketones ; solvation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solution enthalpies of n-hexane, acetone, butan-2-one and octan-2-one in a series of tetrachloromethane-acetonitrile mixtures and the carbonyl stretching absorption frequencies in the IR spectra of these ketones were determined. It was found that over the whole range of concentrations (varying from neat tetrachloromethane up to neat acetonitrile) the solvation enthalpy of these compounds can be obtained additively from the contributions of the alkyl and carbonyl fragments. The solvent effect on the solvation enthalpy of the carbonyl group was found to be satisfactorily correlated with the corresponding IR frequency shifts of the C=O group. It was also found that the sensitivities of the carbonyl IR frequencies to the solvent composition are different for various ketones. From both IR and calorimetric data, the preferential solvation parameters were evaluated. The differences between the IR spectroscopic and calorimetric data are discussed. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 59
    Electronic Resource
    Electronic Resource
    Solvent effects on C=O stretching frequencies of some 1-substituted 2-pyrrolidinones (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 261-272 
    Details
    ISSN: 0894-3230
    Keywords: 1-substituted 2-pyrrolidinones ; C=O stretching frequencies ; solvent effects ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In an effort to model solute-solvent interactions, the C=O stretching frequencies of five 1-substituted 2-pyrrolidinones and four other carbonyl-containing compounds were measured for 30 common solvents. These were then correlated with four empirical parameter sets and one theoretical (computational) parameter set. While an empirical parameter set gave the best correlation equations, the theoretical parameter equations are physically and statistically significant. Solvent volume, polarizability and hydrogen bond donor acidity (capacity) terms are significant in the correlation equations. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 14 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 60
    Electronic Resource
    Electronic Resource
    Molecular orbital calculations on the P - S bond cleavage step in the hydroperoxidolysis of nerve agent VX (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 232-240 
    Details
    ISSN: 0894-3230
    Keywords: P - S bond cleavage ; hydroperoxidolysis ; nerve agent VX ; molecular orbital calculations ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The P - S bond cleavage process in the hydroperoxidolysis of a model system for the nerve agent VX was studied using ab initio and semiempirical molecular orbital methods. Aqueous solvation effects were included through single-point calculations using the semiempirical SM5.2PD/A continuum solvation model and geometries optimized at the HF/MIDI! level of theory. The predominant pathway for P - S bond cleavage involves pseudorotation of a low-energy trigonal bipyramidal intermediate followed by apical ligand ejection. In aqueous solution, the free energy barriers for these processes are found to be 14.3 and 4.6 kcal mol-1, respectively, with electronic energies calculated at the MP2/cc-pVDZ//HF/MIDI! level of theory. By comparison with another continuum model of solvation (PCM), it is concluded that the SM5.2PD/A model performs well even for hypervalent phosphorus species, in spite of not having included any such molecules in the model's parameterization set. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 61
    Electronic Resource
    Electronic Resource
    Gas-phase thermolysis of N-methyl-N-phenyl-tert-butylsulfenamide and morpholinyl-tert-butylsulfenamide (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 407-410 
    Details
    ISSN: 0894-3230
    Keywords: gas-phase thermolysis ; N-methyl-N-phenyl-tert-butylsulfenamide ; morpholinyl-tert-butylsulfenamide ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: N-Methyl-N-phenyl-tert-butylsulfenamide (MPSA) and morpholinyl-tert-butylsulfenamide (MOSA) were thermolyzed in a stirred-flow reactor at temperatures of 340-390 °C and pressures of 7-13 Torr, using toluene as carrier gas, at residence times of 0.3-1.3 s. Isobutene was formed in 99% yield through first-order reactions having the following Arrhenius parameters (A,s-1, Ea, kJ mol-1): MPSA, log A  =  12.41 ± 0.02, Ea  =  158.8 ± 0.2; MOSA, log A  =  12.91 ± 0.22, Ea  =  159 ± 3. It is proposed that the elimination of isobutene takes place by unimolecular reaction mechanisms involving polar, four-center cyclic transition states, forming S-unsubstituted thiohydroxylamines as co-products. Thermochemical parameters, estimated by semiempirical AM1 calculations, are reported for the latter and for the parent molecules. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 62
    Electronic Resource
    Electronic Resource
    NMR and semi-empirical study of the tautomerism of­2,2′-bisbenzimidazolyl (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 411-418 
    Details
    ISSN: 0894-3230
    Keywords: 2,2′-bisbenzimidazolyl ; tautomerism ; NMR ; semi-empirical calculations ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A dynamic NMR study of the tautomerism of 2,2′-bisbenzimidazolyl in DMSO-d6 and a mechanistic interpretation of the process, based on a stepwise, single-proton transfer and formation of a zwitterionic intermediate, are presented. This interpretation is substantiated by semi-empirical calculations of the postulated intermediate and transition state, that yield results which are compared with previous studies on related aliphatic systems. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 63
    Electronic Resource
    Electronic Resource
    Effects of sulfenyl, sulfinyl and sulfonyl groups on acidities and homolytic bond dissociation energies of adjacent C - H and N - H bonds (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 397-406 
    Details
    ISSN: 0894-3230
    Keywords: bond dissociation energy ; acidity ; phenylsulfenylamides ; phenylsulfenylanilides ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acidities and bond dissociation energies (BDEs) of the N-H bond in two phenylsulfenylamides, PhSNHBz and PhSNH-t-Bu, and four phenylsulfenylanilides, 4-GC6H4NHSPh, where G  =  MeO, H, Br and CN, were measured in order to compare the effects of substituents on acidities and BDEs of N - H bonds with those of C - H bonds. The effects of PhS groups on acidities and BDEs in a series of C - H acids were found to be comparable to those on acidities and BDEs of PhS in a similar series of N - H acids. Comparisons were also made of the effects of changing the oxidation state of sulfur in the series PhS, PhSO and PhSO2 on the acidities and BDEs of adjacent N - H and C - H bonds in weak acids. Hammett-type plots of pKHA values for phenyl benzyl sulfones (4-GC6H4CH2SO2Ph) and phenylsulfenylanilides (4-GC6H4NHSPh) were linear vs σp- values. A linear plot was obtained and explained for a plot of BDE of the N - H bonds in remotely substituted phenylsulfonylanilides with σ+ values. Plots of BDEs vs Eox(A-) were also linear for 4-substituted phenylsulfenylanilides (4-GC6H4NHSPh), phenylsulfonylanilides (4-GC6H4NHSO2Ph) and phenyl benzyl sulfones (4-GC6H4CH2SO2Ph). © 1998 John Wiley & Sons, Ltd.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 64
    Electronic Resource
    Electronic Resource
    17O NMR studies on α-diamides (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 387-391 
    Details
    ISSN: 0894-3230
    Keywords: α-diamides ; 17O NMR ; conformation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 17O NMR spectra of several α-diamides were obtained at natural isotopic abundance in acetonitrile solution in order to study the conformations of these compounds in solution. The 17O NMR shifts vary with the intercarbonyl dihedral angle α in a sense opposite to that observed for α-diketones. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 65
    Electronic Resource
    Electronic Resource
    Theoretical study of the tautomerism of 8-azaadenine (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 392-396 
    Details
    ISSN: 0894-3230
    Keywords: 8-azaadenine ; tautomerism ; theoretical study ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The prototropic tautomerism of 8-azaadenine (azaade) was studied theoretically by means of ab initio methods, in both the gas phase and aqueous solution. A number of tautomeric forms were not included in the calculations after applying a stepwise elimination procedure based on both AM1 and HF/6-31G* energy values. The tautomers 9H-azaade, 8H-azaade and 7H-azaade survived to this elimination and their optimized geometries and energies were calculated at the MP2/6-31*//HF/6-31G* level. To include the solvent effects, two self-consistent reaction field method were used: (1) Onsager's SCRF with multipolar expansion up to the hexadecapolar term and (2) the isodensity polarizable continuum method (IPCM). Both methods produce similar results, although the latter represents better the situation in aqueous solution. The stability order in solution, 8H- 〉 9H- 〉 7H-azaade, differs slightly from that found in the gas phase, implying that in general the electrostatic effects in solution are important, but the intrinsic stability of these species in the gas phase overcomes the solvent effect. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 66
    Electronic Resource
    Electronic Resource
    Editorial (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 377-377 
    Details
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: No abstract.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 67
    Electronic Resource
    Electronic Resource
    Electrochemical study of the π* probe dye 5-nitro-5′-dimethylamino-2,2′-bisthiophene (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 419-425 
    Details
    ISSN: 0894-3230
    Keywords: 5-nitro-5′-dimethylamino-2,2′-bisthiophene ; π* probe dye ; cyclic voltammetry ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cyclic voltamograms of the solvatochromic dye 5-nitro-5′-dimethylamino-2,2′-bisthiophene (1), introduced recently as a sensitive π* probe, were recorded in different solvents. An EPR spectrum of the anionic radical of 1 in DMSO was obtained and compared with other spectra of analogous substituted bisthiophene radicals. It was found that the presence of a donor- acceptor pair of substituents in 1-⋅ reduces significantly the rotational barrier of the radical compared with the unsubstituted bithienyl radical anion 2-⋅. This is the result of an electronic repulsion between the donor ring fragment and the added electron in the coplanar radical, which does not exist in 2-⋅. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 68
    Electronic Resource
    Electronic Resource
    Host-guest interactions of calix[4]resorcinarenes with benzene derivatives in conditions of reversed-phase high-performance liquid chromatography. Determination of stability constants (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 426-437 
    Details
    ISSN: 0894-3230
    Keywords: calix[4]resorcinarenes ; organophosphorus compounds ; solvatophobic interactions ; host-guest complexation ; high-performance liquid chromatography ; x-ray analysis ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Reversed-phase high-performance liquid chromatography [LiChrosorb RP-18,UV detection at 254 nm and acetonitrile-water (86:14,v/v) as mobile phase] was applied to studies of the host-guest complexation of tetraalkylcalix[4]resorcinareneoctols and their upper rim phosphoryl, sulfonyl and dialkylaminomethyl derivatives with some aromatic guests in the mobile phase. It was shown that the formation of the inclusion complexes results in changes in the retention of aromatic guests and improves their separation. Stability constants of the complexes were calculated from the dependences of the l/k′ values of the aromatic guest on the concentration of the calix[4]resorcinarene in the mobile phase. The molecular structure of 4,6,16,18-tetrahydroxy-10,12,22,24-tetrakis(dipropoxyphosphoryloxy)-2,8,14,20-tetramethylcalix[4]resorcinarene (12) was determined. Crystal data for 12 are P21/n, a  =  16.708(9) Å, b  =  18.683(6) Å, c  =  20.243(5) Å, β  =  95.75(3)°, V  =  6287(4) Å3 and Z  =  4. Compound 12 exists in a boat conformation, in which two opposite unsubstituted resorcinol rings of the macrocyclic skeleton lie in the plane formed by four methine bridges and two diphosphorylated rings are perpendicular to the plane. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 69
    Electronic Resource
    Electronic Resource
    Ab initio and molecular mechanics (MM3) calculations on alkyl- and arylboronic acids (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 378-386 
    Details
    ISSN: 0894-3230
    Keywords: alkylboronic acids ; arylboronic acids ; ab initio ; MM3 ; molecular mechanics ; force field parameters ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The boronic acid functional group has been incorporated into various biologically important compounds. In order to study this class of compounds better with molecular mechanics, five alkyl- and arylboronic acids were calculated using ab initio methods (Spartan) at the RHF/6-31G* level. MM3 force field parameters were developed based on the theoretically calculated geometries, vibrational spectra, and torsional profiles. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 70
    Electronic Resource
    Electronic Resource
    Base-catalysed hydrolysis of γ-lactones: reactivity-structure correlations for 3-(substituted phenoxy- and thiophenoxymethylene)-(Z )-1(3H )-isobenzofuranones (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 467-474 
    Details
    ISSN: 0894-3230
    Keywords: γ-lactones ; base-catalysed hydrolysis ; reactivity-structure correlations ; isobenzofuranones ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rate coefficients were measured for the base-catalysed hydrolysis of a series of substituted 3-(phenoxy- or thiophenoxymethylene)-(Z)-1(3H)-isobenzfuranones (3-phenoxy- or thiophenoxymethylenephthalides) in 70% (v/v) aqueous dioxane at 30.0 °C, in addition to the carbonyl stretching frequencies in chloroform and tetrachloromethane following deconvolution and band separation, when required. The Hammett reaction constants for the alkaline hydrolysis of the 3-/4-substituted phenoxy and thiophenoxy series are ca 0.75 and 1.10, respectively. These results are related to electrostatic field and resonance effects. Successful correlations between the carbonyl stretching frequencies and substituent constants and the rates of alkaline hydrolysis were found. Computational studies using the semi-empirical AM1 method correctly model both the details of the mechanistic pathway and the substituent effects. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 71
    Electronic Resource
    Electronic Resource
    A new approach to the theoretical estimation of inductive constants (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 437-447 
    Details
    ISSN: 0894-3230
    Keywords: inductive constants ; theoretical estimation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new model of the inductive effect is proposed, allowing highly accurate theoretical calculations of inductive constants for a diversity of substituents, using a simple and readily available system of mathematics. According to this approach, the inductive effect of a substituent is considered in terms of the additive influence of its constituent atoms. A constant inherent capacity for inductive interaction with a reactive center (with a four-coordinate carbon atom chosen for such a center), represented by an atomic constant σA, is ascribed to each atom. Values of σA for a wide variety of atoms are determined, and their physical meaning is revealed to elucidate to a certain extent the physical nature of the inductive effect. In addition, the proposed model permits the convenient use in calculations of group constants σG characterizing the inductive power of groups. Values of σG are determined for molecular fragments that are most widely dealt with in organic chemistry, and the use of σA or σG constants and of their superposition is shown to have, in most cases, little or no effect on the accuracy and reproducibility of the results obtained. It is also shown that, in terms of the developed approach, the inductive effect of a substituent is closely associated with its conformation. Theoretical inductive constants were calculated for 427 organic, aromatic, organometallic and charged substituents, and they showed perfect correlation with the corresponding experimental values. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 72
    Electronic Resource
    Electronic Resource
    Oxidation of mandelic acid by alkaline potassium permanganate. A kinetic study (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 448-454 
    Details
    ISSN: 0894-3230
    Keywords: mandelic acid ; alkaline permanganate ; oxidation ; kinetics ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the oxidation of mandelic acid (MA) by permanganate in aqueous alkaline medium at a constant ionic strength of 1.0 mol dm-3 were studied spectrophotometrically. The reaction shows first-order kinetics in [permanganate ion] and fractional order dependences in [MA] and [alkali]. Addition of products, manganate and aldehyde have no significant effect on the reaction rate. An increase in ionic strength and a decrease in dielectric constant of the medium increase the rate. The oxidation process in alkaline medium under the conditions employed in the present investigation proceeds first by formation of an alkali permanganate complex, which combines with mandelic acid to form another complex. The latter decomposes slowly followed by a fast reaction between the free radical of mandelic acid and another molecule of permanganate to give products. The reaction constants involved in the mechanism were derived. There is good agreement between the observed and calculated rate constants under different experimental conditions. The reaction was studied at different temperatures and activation parameters were computed with respect to the slow step of the proposed mechanism. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 73
    Electronic Resource
    Electronic Resource
    Selective arylation of exocyclic N-position of 2-pyrimidylnitrenium ion photolytically generated from tetrazolo-[1,5-a]pyrimidine in the presence of trifluoroacetic acid (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 478-484 
    Details
    ISSN: 0894-3230
    Keywords: Selective arylation ; exocyclic N-position ; 2-pyrimidylnitrenium ion ; tetrazolo[1,5a]pyrimidine ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photo-reactions of tetrazolo[1,5-a]pyrimidine (1) with benzene (2a) and substituted benzenes (2b-f) in the presence of trifluoroacetic acid (TFA) gave 2-(2-, 3- and 4-substituted anilino)pyrimidines (3-5) together with 2-aminopyridine (6) and biphenyl (7) or diarylmethanes (8b, 8c and 8e). From the effect of heavy-atom solvent on the reactions, it is reasonable to assume that 3-5 are formed via a singlet species, but 6-8 via a triplet species. The intermediacy of 2-pyrimidylnitrenium ion is consistent with the evidence derived by the above effect, by a Hammett plot with ρ = -2.9 and by effects of solvent nucleophilicity and counter-anions. The selective exocyclic N-arylation giving 3-5 is discussed. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 74
    Electronic Resource
    Electronic Resource
    Synthesis, structural, conformational and pharmacological study of esters derived from 3-methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9α-ol as potential analgesics (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 125-132 
    Details
    ISSN: 0894-3230
    Keywords: 3-methyl-2, 4-diphenyl-3-azabicyclo[3.3.1]nonan-9α-ol esters ; analgesics ; synthesis ; structure ; conformation ; pharmacological assays ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of esters derived from 3-methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9α-ol (1) was synthesized and studied by 1H and 13C NMR spectroscopy, and the crystal structure of 3-methyl-2,4-diphenyl-9α-(3,5-dimethylbenzoyloxy)-3-azabicyclo[3.3.1]nonane (2) was determined by x-ray diffraction. The compounds studied display in CDCl3 a preferred flattened chair-chair conformation. This bicycle conformation is similar to that found for 2 in the crystal state. Pharmacological assays on mice were performed to evaluate drug-induced behavioral alteration, peripheral or central acute toxicity and analgesic activity. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 75
    Electronic Resource
    Electronic Resource
    Stereospecific nucleophilic trapping of encounter complexes between photoexcited 1-cyanonaphthalene and norbornadiene (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 101-108 
    Details
    ISSN: 0894-3230
    Keywords: encounter complexes ; 1-cyanonaphthalene ; norbornadiene ; stereospecific ; nucleophilic trapping ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photo-induced electron donor-acceptor reactions between 1-cyanonaphthalene (CNN) and norbornadiene (N) generate products of several structure types. Methanol adducts (1-3) formed in polar solvents are rationalized via the radical cation, N+·, and stereospecific (exo-) nucleophilic attack by methanol. In less polar solvents, CNN and N form [2 + 2]-cycloadducts, exclusively on the exo-face of N. In non-polar solvents containing methanol, CNN, N and methanol combine to form 1:1:1 adducts, containing the sensitizer on the endo- and the methoxy groups on the exo-face. The formation of these products is rationalized via the trapping of encounter complexes of different geometries. Any rearrangement of the norbornenyl system can be eliminated, since neither tricyclyl nor 7-methoxynorbornenyl structures are formed. Apparently, the alcohol captures an endo-encounter complex of CNN and N by attack from the exo-face, similar to the attack of methanol on N+·. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 76
    Electronic Resource
    Electronic Resource
    Gain or loss of aromaticity in Diels-Alder transition states and adducts: a theoretical investigationThis paper was presented at the Satellite Meeting on Structural and Mechanistic Organic Chemistry: A Tribute to Norman L. Allinger, held in Athens, GA, USA, June 3-7, 1997. (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 133-140 
    Details
    ISSN: 0894-3230
    Keywords: aromaticity ; Diels-Alder transition states ; Diels-Alder adducts ; reaction mechanism ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Semiempirical, ab initio and DFT investigations on the mechanism of the Diels-Alder reactions of a set of masked dienes (ring-fused dienes), viz. o-quinodimethane, anthracene and α-vinylnaphthalene, with ethylene, and reactions of α-vinylnaphthalene with maleic anhydride and p-benzoquinone were performed with a view to understanding the role of masking factors on the activation and reaction energies. The reactions were found to occur in a concerted fashion through synchronous transition states (TSs) in the first two reactions and through asynchronous TS in the other case. Of the compounds studied, o-quinodimethane is the most reactive diene both in a kinetic and a thermodynamic sense. α-Vinylnaphthalene reacts faster with maleic anhydride than p-benzoquinone, as expected, and two possible stereoselective TSs, one endo and the other exo, have been located for the reactions of α-vinylnaphthalene with the above dienophiles. Calculations show that the relative gain or loss of aromatic stabilization of the benzonoid ring in the transition state and in the product seems to play a major role in the kinetic and thermodynamic control of these reactions. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 77
    Electronic Resource
    Electronic Resource
    Infrared spectra and conformation of methyl-substituted benzoic acidsPresented in part at the VIth International Conference on Correlation Analysis in Chemistry, Prague, 5-9 September 1994. (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 141-148 
    Details
    ISSN: 0894-3230
    Keywords: methylbenzoic acids ; infrared spectra ; conformation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Infrared spectra of all isomers of polymethyl-substituted benzoic acids were recorded in the carbonyl and hydroxyl regions in tetrachloromethane at various concentrations and interpreted in terms of conformation. According to a plot of ν(C=O) of the monomeric form vs Hammett substituent constants σ, these compounds may be classified into two classes. Derivatives with none or only one methyl group in the ortho position are concluded to exist in an equilibrium of two planar conformations, unless the equilibrium is degenerate. Derivatives with two ortho-situated methyl groups are concluded to take up one non-planar conformation. These findings are supported by the shape of the hydroxyl and carbonyl bands, which are unsymmetrical in the former class, although they could not be reliably separated into bands pertinent to the individual conformers. This conclusion is at variance with the common interpretation which has invariably ascribed to these and similar ortho derivatives non-planar conformations with a variable torsional angle. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 78
    Electronic Resource
    Electronic Resource
    Ab initio calculations on P - C bond cleavage in phosphoranyl radicals: implications for the biodegradation of organophosphonate derivatives (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 149-154 
    Details
    ISSN: 0894-3230
    Keywords: P - C bond cleavage ; phosphoranyl radicals ; organophosphonate biodegradation ; ab initio calculations ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Barrier heights for P - C bond homolysis in P-hydroxy-P-methyl-P,P-dioxophosphoranyl and P,P,P-trihydroxy-P-methylphosphoranyl were calculated using well correlated levels of electronic structure theory. The best estimate for the difference in barriers between the two indicates that homolysis is more facile for P,P,P-trihydroxy-P-methylphosphoranyl by roughly 9 kcal mol-1. This result suggests that bacterial pathways leading to P - C bond cleavage in organophosphonate derivatives will preferentially proceed via initial one-electron reduction of substrates rather than oxidation. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 79
    Electronic Resource
    Electronic Resource
    Mechanism of cycloaddition to indolizines (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 201-208 
    Details
    ISSN: 0894-3230
    Keywords: indolizines ; cycloaddition ; reaction mechanism ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The peculiarities of [8+2] cycloaddition reactions of indolizines with dienophiles are reviewed. Quantum chemical SINDO1, AM1 and ab initio calculations of transition states were performed for [8+2] cycloaddition reactions of indolizine and 6-nitroindolizine with a series of alkenes with donor and acceptor groups. The calculations predict a dipolar cycloaddition mechanism (electrophilic addition and ring closure) for reactions of indolizine and 6-nitroindolizine with nitroethylene. For the reaction of 6-nitroindolizine with N,N-dimethylaminoethylene, the predicted mechanism corresponds to a previously unknown ‘inverse’ dipolar cycloaddition (nucleophilic addition and ring closure). © 1998 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 80
    Electronic Resource
    Electronic Resource
    Theoretical studies on the gas-phase nucleophilic substitution reactions of benzyl chlorides with phenoxides and thiophenoxides (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 115-124 
    Details
    ISSN: 0894-3230
    Keywords: cross-interaction constants ; gas-phase nucleophilic substitution reactions ; PM3 MO ; benzyl chlorides ; phenoxides ; thiophenoxides ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Gas-phase nucleophilic substitution reactions of Y-benzyl chlorides with X-phenoxide and X-thiophenoxide nucleophiles were investigated theoretically using the PM3 semi-empirical MO method. The Leffler-Grunwald rate-equilibrium and Brønsted correlations predict that the degree of bond formation in the transition state (TS) is approximately 45 and 40% on the reaction coordinate for the phenoxides and thiophenoxides, respectively. For a weaker nucleophile, a later TS is obtained with an increased bond making and breaking. The variation of the TS structure with substituents in the nucleophile is thermodynamically controlled and is well correlated by rate-equilibrium relationships. In contrast, the TS variation (a tighter TS) with substituent (for a stronger acceptor Y) in the substrate is dependent only on variations of the intrinsic barrier and so cannot be correlated by such thermodynamically based rate-equilibrium relationships. The gas phase ρX and ρY values are much greater in magnitude than those in solution. A similar gas-phase theoretical cross-interaction constant, ρXY (ca -0.60), is obtained for both phenoxides and thiophenoxides, which is in good agreement with the experimental value (-0.62) for the thiophenoxide reactions in MeOH at 20.0 °C. The oxy and sulfur anion bases lead to a similar TS structure, but a lower reactivity for the former is due to a greater endothermicity of the reaction. A relatively wide range variation of the reaction energies, ΔG°, can be ascribed to the loss of resonance stabilization of anion nucleophiles upon product formation. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 81
    Electronic Resource
    Electronic Resource
    Osmium(VIII)/ruthenium(III) catalysis of periodate oxidation of acetaldehyde in aqueous alkaline medium (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 171-176 
    Details
    ISSN: 0894-3230
    Keywords: acetaldehyde ; oxidation ; periodate ; osmium (VIII) catalysis ; ruthenium (III) catalysis ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Os(VIII) and Ru(III) catalysis of the periodate oxidation of acetaldehyde in aqueous alkaline medium was investigated. The catalytic efficiency is Ru(III)〈Os(VIII). The product of oxidation in both cases is acetate and IO3-. The stoichiometry is the same in both catalyzed reactions, i.e. [IO4-]:[CH3CHO] = 1:1. Probable mechanisms are proposed and discussed. The reaction constants involved in the mechanisms are derived. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 82
    Electronic Resource
    Electronic Resource
    Solvolysis of benzylic chlorides with extended charge delocalization. α-tert-butyl(2-naphthyl)methyl, 9-fluorenyl and monosubstituted benzhydryl chlorides (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 223-229 
    Details
    ISSN: 0894-3230
    Keywords: Solvolysis ; Grunwald-Winstein-type analysis ; Hammett-type analysis ; YxBnCl scale ; 1-aryl-1-phenylmethyl cations ; Mulliken population analysis ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rate constants of solvolysis of α-tert-butyl(2-naphthyl)methyl chloride (1), 9-fluorenyl chloride (2) and a series of monosubstituted benzhydryl chlorides (3) in a wide range of solvents were measured. Grunwald-Winstein-type correlation analysis of log k for 2 and 3 against YBnCl, with or without nucleophilicity N, yielded less satisfactory linear correlations than that against log k(1). A new scale of solvent ionizing power, YxBnCl, for the correlation of solvolytic reactivities of benzylic chlorides with extended charge delocalization based on log k(1) was developed. Application to the mechanistic study suggested the solvolysis of 2 and 4-nitrobenzhydryl chloride were non-limiting. Hammett plots against σ+ constants exhibited more negative ρ values in less nucleophilic solvents. In a benzhydryl chloride containing a strong deactivating substituent, such as 4-nitro, the positive charge delocalizes mainly over the unsubstituted ring in the cationic transition state. The uneven charge distribution was also confirmed by Mulliken population analysis at the level of the RHF/6-31G*//RHF/3-21G(*) basis set for cations. Comparison of the results of correlation analysis using the equation log(k/k0) = mY vs the equation log(k/k0) = mY+hI, and using the equation log(k/k0) = mY+lN vs the equation log(k/k0) = mY+lN+hI indicated the use of YBnCl or YxBnCl could give a better understanding of solvolytic mechanisms than the combinatorial use of YCl and I. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 83
    Electronic Resource
    Electronic Resource
    Empirical treatment of solvent-solute interactions: medium effects on the electronic absorption spectrum of β-carotene (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 193-200 
    Details
    ISSN: 0894-3230
    Keywords: Solvent-solute interactions ; β-carotene ; electronic absorption spectrum ; solvent effects ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solvent effects on the wavenumber of the maximum of the longest wavelength electronic absorption band of all-trans-β-carotene were determined in 34 solvents. Together with results from previous studies, a data set for 51 solvents, mostly non-hydrogen bond donors, was constructed. This information was analyzed in terms of reaction field models and also showed its value for correlation purposes when used either alone or in combination with standard empirical solvent polarity-polarizability scales. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 84
    Electronic Resource
    Electronic Resource
    Theoretical study on pyrolysis and sensitivity of energetic compounds. Part 4. Nitro derivatives of phenols (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 177-184 
    Details
    ISSN: 0894-3230
    Keywords: nitro derivatives of phenols ; pyrolysis initiation reactions ; impact sensitivity ; UHF-SCF-AM1 MO method ; activation energy. ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The UHF-SCF-AM1 MO method was applied to the study of two kinds of pyrolysis reactions of six nitro derivatives of phenols (homolysis reaction by rupture of the C - NO2 bond into radicals and isomerization reaction involving phenolic hydrogen transferring to oxygen on the NO2 group). The molecular geometries of reactants, transition states and products were fully optimized. The potential energy curves and activation energies were first obtained. The results show that this category of compounds is more easily initiated via isomerization reactions than by homolysis reactions. The parallel relationship among the Wiberg bond order of the pyrolysis-initiation H - O bond in the molecule of a reactant, the activation energy of the isomerization reaction breaking the H - O bond and impact sensitivity of the reactant gives ‘the principle of the smallest bond order’ (PSBO) powerful support. The sensitizing effect of a phenol group was elucidated based on calculation results. The different influences of OH and NO2 groups on the heat of formation of a molecule are discussed. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 85
    Electronic Resource
    Electronic Resource
    Unexpected rate enhancement in the intramolecular carboxylic acid-catalyzed cleavage of o-carboxybenzohydroxamic acid (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 216-222 
    Details
    ISSN: 0894-3230
    Keywords: o-carboxybenzohydroxamic acid ; phthalic anhydride ; phthalic acid ; hydrolysis ; intramolecular acid catalysis ; kinetics ; activation parameters ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Phthalic anhydride was detected spectrophotometrically in the hydrolysis of o-carboxybenzohydroxamic acid (OCBA) in CH3CN-H2O solvent containing 0.03 mol dm-3 HCl. Pseudo-first-order rate constants (k1) for hydrolysis of OCBA are almost independent of the change in CH3CN content from 10 to 80% (v/v) in mixed aqueous solvents. The rate constants k1 are more than 10-fold larger than the corresponding rate constants for hydrolysis of phthalamic acid. These observations are explained in terms of a mechanism slightly different from the mechanism for hydrolysis of phthalamic acid. The activation parameters, ΔH* and ΔS*, are not affected appreciably by an increase in CH3CN content from 10 to 80% in mixed aqueous solvents. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 86
    Electronic Resource
    Electronic Resource
    Solute-solvent and solvent-solvent interactions in binary solvent mixtures. Part 7. Comparison of the enhancement of the water structure in alcohol-water mixtures measured by solvatochromic indicators (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 185-192 
    Details
    ISSN: 0894-3230
    Keywords: solute-solvent interactions ; solvent-solvent interactions ; binary solvents ; alcohol-water mixtures ; water structure ; solvatochromic indicators ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A preferential solvation model that takes into account the enhancement of the structure of water when small amounts of alcohol are added was applied to solvatochromic data for binary mixtures of water with 2-methylpropan-2-ol, propan-2-ol, ethanol and methanol. Application of the model allows the calculation of the effect of the enhancement of the water structure on solvatochromic solvent properties. It is demonstrated that the enhancement of water structure increases the solvent dipolarity/polarizability and hydrogen-bond donor acidity and decreases the solvent hydrogen-bond acceptor basicity. The effect decreases in the order 2-methylpropan-2-ol-water, propan-2-ol-water, ethanol-water and methanol-water. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 87
    Electronic Resource
    Electronic Resource
    Structural dependence of heterolytic bond dissociation energy of carbon-carbon σ bonds in hydrocarbons (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 157-170 
    Details
    ISSN: 0894-3230
    Keywords: heterolytic bond dissociation energy ; carbon-carbon σ bonds ; hydrocarbons ; structural dependence ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The coordination of a resonance-stabilized hydrocarbon cation and anion yielded a series of unprecedented hydrocarbons, which are susceptible to thermal heterolytic cleavage of carbon-carbon σ bonds in polar media, generating the original ions under reversible conditions. When the component ions were sufficiently stabilized, some ion pairs were even isolated as solids, thus providing the first examples of hydrocarbon salts. The direct observation of the heterolysis by means of spectroscopy permitted reliable thermodynamic treatments of the observed degree of ionic dissociation. Correlation of the free energy of heterolysis with solvent dielectric constants and parameters of ion stabilities such as pKHA, pKR+ and redox potentials revealed the importance of the thermodynamic stabilities of ions, the degree of solvation and steric congestion in the starting molecule as major controlling factors in the heterolysis. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 88
    Electronic Resource
    Electronic Resource
    Correlation of the rates of solvolysis of the N,N-diphenylcarbamoylpyridinium ion (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 273-276 
    Details
    ISSN: 0894-3230
    Keywords: N,N-diphenylcarbamoylpyridinium ion ; solvolysis ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solvolyses of the N,N-diphenylcarbamoylpyridinium ion are subject to specific and/or general base catalysis, which can be eliminated by addition of perchloric acid or increased, especially in fluoroalcohol-containing solvents, by addition of pyridine. The uncatalyzed solvolyses in aqueous methanol and aqueous ethanol involve a weakly nucleophilically assisted (l  =  0.22) heterolysis and the solvolyses in the pure alcohols are anomalously slow. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 89
    Electronic Resource
    Electronic Resource
    Effects of ionic and non-ionic micelles on rate of hydroxide ion-catalyzed hydrolysis of securinine (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 209-215 
    Details
    ISSN: 0894-3230
    Keywords: securinine ; cationic micelles ; anionic micelle ; non-ionic micelle ; alkaline hydrolysis ; kinetics ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of micelles of cetyltrimethylammonium bromide (CTABr), tetradecyltrimethylammonium bromide (TTABr), sodium dodecyl sulfate (SDS) and polyoxyethylene 10 lauryl ether (C12E10) on the rates of alkaline hydrolysis of securinine were studied at a constant [-OH] (0.05 M). An increase in the total concentrations of CTABr, TTABr, SDS and C12E10 from 0.0 to 0.2 M causes a decrease in the observed pseudo-first-order rate constants (kobs) by factors of ca 2.5, 3, 7 and 4, respectively. The observed data are explained in terms of pseudophase and pseudophase ion-exchange (PIE) models of micelle. The binding constants, KS, of securinine with SDS, C12E10, CTABr and TTABr micelles are 32.4, 14.8, 22.1, and 9.1 M-1, respectively. The magnitudes of the second-order rate constants, kM, for the reactions in the micellar pseudophase are negligible compared with the corresponding rate constant, kW, for the reaction occurring in the aqueous pseudophase for CTABr, TTABr, SDS and C12E10. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 90
    Electronic Resource
    Electronic Resource
    Colloidal CdS-induced photocatalytic reaction of 2-methylindole - mechanistic analysis of oxidation of indoles (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 277-282 
    Details
    ISSN: 0894-3230
    Keywords: colloidal CdS-induced photochemical reactions ; photocatalytic reactions ; photooxidation ; 2-methylindole ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2-Methylindole (2-MI) is adsorbed on the surface of colloidal CdS particles with an adsorption intensity of 0.6 × 103 dm3 mol-1. A new emission band at 530 nm is produced by forming an exciplex between excited CdS and 2-MI and the red emission due to CdS is simultaneously quenched. The emission maxima of green bands for different indoles increase in the order indole 〈 tryptophan 〈 2-MI 〈 3-MI and are observed at 508, 520, 530 and 540 nm, respectively. The shift in emission maxima is related to the oxidation potential of these substrates. The irradiation of an aerated reaction mixture containing CdS and 2-MI with visible light induces the oxidation of adsorbed 2-MI by photogenerated holes to produce 2-methyl-3-indolinone and 2-acetamidobenzaldehyde. The latter product is formed due to oxidative C - C bond cleavage of the pyrrole ring. The reactivity of trapped holes towards the adsorbed 2-MI is evidenced by a decrease in the lifetime of the red emission of CdS in the presence of 2-MI. In this reaction the possibility of the participation of singlet oxygen is ruled out. A general mechanism of CdS-induced oxidation of indoles is discussed. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 91
    Electronic Resource
    Electronic Resource
    Conformational analysis of a 12-membered crown dithioether in the solid state and in solution (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 241-253 
    Details
    ISSN: 0894-3230
    Keywords: crown dithioether ; conformational analysis ; multicomponent equilibrium ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The solid-state molecular structure and the conformational behaviour in solution of the 12-membered crown dithioether 8-methyl-1,4-dioxa-7,10-dithiacyclododecane-5,12-dione were studied by x-ray crystallography, 1H and 13C NMR spectroscopy and molecular mechanics. The conformational rigidity of some constituent structural fragments allowed a detailed analysis of the structure and distribution of the conformers. A protocol for studies of multiconformational equilibrium was developed by means of the combined use of structure calculations and dynamic NMR measurements. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 92
    Electronic Resource
    Electronic Resource
    Metal-catalyzed carbenoid reactions with iodonium and sulfonium ylides (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 321-333 
    Details
    ISSN: 0894-3230
    Keywords: metal-catalyzed carbenoid reactions ; iodonium ylides ; sulfonium ylides ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transition metal-catalyzed decomposition of phenyliodonium and diphenylsulfonium ylides was investigated with regard to application in asymmetric carbenoid reactions. Phenyliodonium ylides react in the presence of Rh(II) catalysts with the same selectivity in inter- and intramolecular cyclopropanations as the corresponding diazo compounds, and intramolecular CH insertions proceed with identical enantioselectivities. With diphenylsulfonium ethoxycarbonylmethylide the Cu(I)-catalyzed cyclopropanation of olefins affords trans/cis ratios and asymmetric inductions identical with those of diazo compounds, but with Rh(II) catalysts some small, although significant, selectivity variations occur, which are ascribed to coordination of diphenyl sulfide to one of the coordination sites of the catalyst. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 93
    Electronic Resource
    Electronic Resource
    Principles of physical organic chemistry for molecular architecture and functions (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 299-304 
    Details
    ISSN: 0894-3230
    Keywords: molecular architecture ; molecule-based magnets ; biopolymers ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Application of the principles of physical organic chemistry to the construction of molecule-based magnets is discussed. Not only the magnetic structures of conventional magnets but also secondary and tertiary structures of biopolymers are instrumental in the molecular design. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 94
    Electronic Resource
    Electronic Resource
    Studies of reactive intermediates using matrix and gas-phase techniques (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 350-355 
    Details
    ISSN: 0894-3230
    Keywords: 1,3-dipoles ; cumulenes ; infrared spectroscopy ; mass spectrometry ; flash vacuum thermolysis ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the direct investigation of reactive intermediates it is particularly valuable to use a combination of several spectroscopic techniques. This commentary highlights recent examples, using primarily flash vacuum thermolysis for the generation of the intermediates, and matrix IR spectroscopy in conjunction with gas-phase mass spectrometric methods for their identification. The examples include nitrile imines, nitrile ylides, nitrile sulfides and selenides, dinitrogen sulfide and several novel cumulenes (X=C=C=Y, RN=C=C=C=X). © 1998 John Wiley & Sons, Ltd.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 95
    Electronic Resource
    Electronic Resource
    Non-cross-linked and cross-linked poly(alkylmethyldiallylammonium halides): synthesis and aggregation behavior (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 305-320 
    Details
    ISSN: 0894-3230
    Keywords: poly(alkylmethyldiallylammonium halides) ; aggregation behavior ; polyelectrolytes ; polysoaps ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrophobically modified polyelectrolytes (polysoaps) are a unique class of water-soluble polymers containing distinct hydrophobic and hydrophilic regions. Above a certain concentration, polysoaps form intramolecular and intermolecular aggregates in aqueous solution. They have attracted much attention not only for their ability to mimic some functions demonstrated by biopolymers but also for their important industrial applications. This review highlights some interesting features of novel non-cross-linked and cross-linked poly(alkylmethyldiallylammonium halides) that have been described in recent years. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 96
    Electronic Resource
    Electronic Resource
    Is the brain ready for physical organic chemistry? (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 334-340 
    Details
    ISSN: 0894-3230
    Keywords: brain chemistry ; membrane proteins ; molecular neurobiology ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Efforts to developed detailed insights into the structure and function of the molecules of memory, thought and sensory perception - physical organic chemistry on the brain - are described. By combining more conventional chemical tools with a number of techniques adapted from modern biology, it is now possible to perform systematic structure-function studies on the integral membrane proteins that play a central role in molecular neurobiology. There are substantial challenges associated with such studies, but we believe the potential payoff is considerable. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 97
    Electronic Resource
    Electronic Resource
    Vicarious nucleophilic substitution of hydrogen. Mechanism and orientation (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 341-349 
    Details
    ISSN: 0894-3230
    Keywords: vicarious nucleophilic substitution ; hydrogen ; mechanism ; orientation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrogens located at activated positions in electrophilic arenes, e.g. ortho and para hydrogens in nitrobenzenes, can be replaced with a nucleophile moiety provided there is at least one nucleofuge X connected to the nucleophilic centre. As the group really leaving in this hydrogen substitution process is not the hydride anion but X, the reaction has been named vicarious nucleophilic substitution of hydrogen (VNS). The concepts on the mechanism of the reaction and their experimental background are presented. Reactivity and orientation - the fundamental questions concerning synthetical applications of VNS - are discussed in light of the supposed mechanistic picture.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 98
    Electronic Resource
    Electronic Resource
    Preface (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 291-291 
    Details
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: No Abstract
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 99
    Electronic Resource
    Electronic Resource
    Unusual reactivity of highly strained cyclophanesDedicated to Prof. Dr Maitland Jones, Jr, on the occasion of his 60th birthday (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 362-376 
    Details
    ISSN: 0894-3230
    Keywords: highly strained cyclophanes ; reactivity ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An essential feature of the concept of aromaticity has been the stability and lack of reactivity of aromatics relative to that of other unsaturated compounds. Contrary to this general experience, high and unusual reactivity is encountered when simple, monocyclic benzene rings are bent by short bridges into a boat-shaped conformation, as is the case in small [n] paracyclophanes (n ≤ 8) and [n]metacyclophanes (n ≤ 7). This is illustrated, mostly with examples taken from the authors' own work, for thermal and photochemical behavior and reactions with electrophiles, nucleophiles and dienophiles. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 100
    Electronic Resource
    Electronic Resource
    Heterogeneous catalysis of organic reactions (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 356-361 
    Details
    ISSN: 0894-3230
    Keywords: heterogeneous catalysis ; organic reactions ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A decade's worth of work is reviewed: building on the demonstrated prowess of heterogeneous catalysis in industrial organic chemistry, the author's laboratory devised efficient catalysts for a number of organic reactions, based on aluminosilicates such as clays and zeolites. This review also spells out, at a time when creative research is overshadowed by imitative research, some of the methodological musts that also happen to characterize physical organic chemistry: the devising of experiments so that accurate numerical data can be obtained; the importance of remote, interdisciplinary connections; the need for estrangement from stereotypic preconceptions that may obscure the true explanations for the phenomena; and the over-riding need for concerning oneself only, or at least predominantly, with the important facts that nature tells, if one cares to listen. © 1998 John Wiley & Sons, Ltd.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...