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  • 2000-2004  (27)
  • 1980-1984  (1,316)
  • 1970-1974  (410)
  • 1955-1959  (11)
  • Atomic, Molecular and Optical Physics  (1,709)
  • transformation
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  • 1
    Electronic Resource
    Electronic Resource
    The Effects of Molybdenum on the High-Temperature Oxidation Resistance of Thin Foils of Fe–20Cr–5Al at Very High Temperatures (2000)
    Springer
    Oxidation of metals 53 (2000), S. 561-576 
    Details
    ISSN: 1573-4889
    Keywords: Fe–Cr–Al alloy ; oxidation ; molybdenum ; breakaway oxidation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thin foils of Fe–20Cr–5Al alloys are susceptible to breakawayoxidation once the aluminum content of the substrate has fallen below somecritical value. The combined addition of 0.1 wt.% lanthanum and 0, 1, or 2wt% molybdenum has a beneficial effect on the high-temperature oxidation ofsuch foils. Lanthanum has the well-known reactive-element effect on adhesionof the protective alumina scale, thereby increasing the time to onset ofbreakaway oxidation, while, for alloys containing molybdenum, breakawayoxide spreads relatively slowly over the specimen in comparison to alloysthat contain no molybdenum. In particular, molybdenum-containing alloys areable to develop a protective Cr2O3 layer at the breakawayoxide–substrate interface. Conversely, molybdenum-free alloys form aninternal-oxide zone in the substrate adjacent to this interface, rather thana Cr2O3 layer, so breakaway oxide spreads rapidly. A martensitic phase isobserved in the substrate adjacent to the breakaway oxide formed on Fe–20Cr–5Al–La specimens, which means that theα-phase has transferred to the γ -phase at the temperature ofthe oxidation test (1150°C). Conversely, α-phase is retained inthe molybdenum-containing alloy, even after breakaway takes place, sincemolybdenum, which is a strong ferrite former, is enriched in the alloyadjacent to areas of breakaway oxide. The diffusion rate of chromium isslower in the γ than in the α-phase so a continuouschromium-rich oxide layer, which is effective in inhibiting breakawayoxide from spreading, cannot be established at the breakawayoxide–substrate interface for the molybdenum-free alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004689211302
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  • 2
    Electronic Resource
    Electronic Resource
    Transformation of the tropane alkaloid-producing medicinal plant Hyoscyamus muticus by particle bombardment (2000)
    Springer
    Transgenic research 9 (2000), S. 163-168 
    Details
    ISSN: 1573-9368
    Keywords: Hyoscyamus muticus ; particle bombardment ; transformation ; tropane alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report an efficient whole plant transformation system for Hyoscyamus muticus, an important medicinal plant of the Solanaceous family. We developed a system using a plasmid carrying the nptII and gusA genes, which was delivered into leaf explants by particle bombardment. Ten percent of bombarded leaf explants formed kanamycin-resistant callus, from which putative transgenic plants were recovered. The nptII gene conferring kanamycin resistance was found to be incorporated into the genome of all transgenic plants screened. Over 50% of the kanamycin resistant plants showed strong expression of the non-selected gusA gene. The majority of transgenic plants reached maturity, could be self pollinated, and produced fertile seed. A simple and efficient whole plant transformation system for this medicinal plant is an important step in furthering our understanding of tropane alkaloid production in plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008912330067
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  • 3
    Electronic Resource
    Electronic Resource
    Transgenic Trifolium repens with foliage accumulating the high sulphur protein, sunflower seed albumin (2000)
    Springer
    Transgenic research 9 (2000), S. 103-113 
    Details
    ISSN: 1573-9368
    Keywords: inheritance ; Rubisco small subunit promoters ; sonication ; sulphur nutrition ; sunflower albumin ; transformation ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract With the aim of increasing the rumen-protected level of the sulphur amino acids cysteine and methionine in Trifolium repens, we introduced the coding sequence of the sunflower seed albumin (SSA) into T. repens by Agrobacterium tumefaciens-mediated transformation. The SSA gene was modified such that the protein would be localised to the endoplasmic reticulum (ER). Four different T-DNA constructions all containing the SSA gene driven by either the promoter of a gene encoding the small subunit of ribulose bisphosphate carboxylase (Rubisco) from Arabidopsis thaliana (A ssu), the promoter of the gene encoding the small subunit of Rubisco of Medicago sativa (L ssu), or the Cauliflower Mosaic Virus 35S promoter (CaMV35S), were transferred to T. repens cv. Haifa. Transgenic T 0-plants and inter-transgenic hybrids were analysed for the level of SSA accumulation in the leaves by western blotting. The highest observed level of SSA accumulation was 0.1% of total extractable leaf protein. We observed that the promoter had a substantive effect on the level of SSA accumulation with A ssu〉CaMV35S〉L ssu. Results from the inter-transgenic hybrids showed that the capacity to synthesise SSA was inherited. However the level of SSA accumulation in the leaves generally appears not to be additive with extra transgenic loci. During this work, we attempted to improve the efficiency of A. tumefaciens-mediated transformation of T. repens using the SAAT-method (Sonication Assisted Agrobacterium-mediated Transformation) on cotyledons of T. repens. T-DNA transfer was in general not enhanced by sonication compared to traditional A. tumefaciens-mediated transformation. Furthermore, Southern blot analyses of plants regenerated from the same cotyledon after A. tumefaciens treatment and under selection, indicated that multiple shoots were usually derived from the same transformation event. We concluded from these results that only one plant from each A. tumefaciens-treated cotyledon should be taken to avoid transgenic clones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008967409302
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  • 4
    Electronic Resource
    Electronic Resource
    Efficient Production of Transgenic Cassava Using Negative and Positive Selection (2000)
    Springer
    Transgenic research 9 (2000), S. 405-415 
    Details
    ISSN: 1573-9368
    Keywords: Manihot esculenta ; transformation ; Agrobacterium tumefaciens ; mannose ; hygromycin ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to improve the efficiency of cassava (Manihot esculenta Crantz) transformation, two different selection systems were assessed, a positive one based on the use of mannose as the selective agent, and a negative one based on hygromycin resistance encoded by an intron-containing hph gene. Transgenic plants selected on mannose or hygromycin were regenerated for the first time from embryogenic suspensions cocultivated with Agrobacterium. After the initial selection using mannose and hygromycin, 82.6% and 100% of the respective developing embryogenic callus lines were transgenic. A system allowing plant regeneration from only transgenic lines was designed by combining chemical selection with histochemical GUS assays. In total, 12 morphologically normal transgenic plant lines were produced, five using mannose and seven using hygromycin. The stable integration of the transgenes into the nuclear genome was verified using PCR and Southern analysis. RT-PCR and northern analyses confirmed the transgene expression in the regenerated plants. A rooting test on mannose containing medium was developed as an alternative to GUS assays in order to eliminate escapes from the positive selection system. Our results show that transgenic cassava plants can be obtained by using either antibiotic resistance genes that are not expressed in the micro-organisms or an antibiotic-free positive selection system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026509017142
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  • 5
    Electronic Resource
    Electronic Resource
    Floral Spray Transformation Can Efficiently Generate Arabidopsis (2000)
    Springer
    Transgenic research 9 (2000), S. 471-486 
    Details
    ISSN: 1573-9368
    Keywords: Arabidopsis thaliana ; Agrobacterium tumefaciens ; floral spray ; SOD ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study, floral spray and floral dip were used to replace the vacuum step in the Agrobacterium-mediated transformation of a superoxide dismutase (SOD) gene into Arabidopsis. The transgene was constructed by using a CaMV 35S promoter to drive a rice cytosolic CuZnSOD coding sequence in Arabidopsis. The transgene construct was developed in binary vectors and mobilized into Agrobacterium. When Arabidopsis plants started to initiate flower buds, the primary inflorescence shoots were removed and then transformed by floral spray or floral dip. More than 300 transgenic plants were generated to assess the feasibility of floral spray used in the in planta transformation. The result indicates that the floral spray method of Agrobacterium can achieve rates of in planta transformation comparable to the vacuum-infiltration and floral dip methods. The floral spray method opens up the possibility of in planta transformation of plant species which are too large for dipping or vacuum infiltration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026522104478
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in lipid and protein constituents of rafts and caveolae in multidrug resistant cancer cells and their functional consequences (2000)
    Springer
    Glycoconjugate journal 17 (2000), S. 253-259 
    Details
    ISSN: 1573-4986
    Keywords: Cancer ; caveolae ; caveolin ; cholesterol ; glucosylceramide ; multidrug resistance ; rafts ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The carcinogenic process involves a complex series of genetic and biochemical changes that enables transformed cells to proliferate, migrate to secondary sites and, in some cases, acquire mechanisms that make cancer cells resistant to chemotherapy. This phenomenon in its most common form is known as multidrug resistance (MDR). It is usually mediated by overexpression of P-glycoprotein (P-gp) or other plasma membrane ATPases that export cytotoxic drugs used in chemotherapy, thereby reducing their efficacy. However, additional adaptive changes are likely to be required in order to confer a full MDR phenotype. Recent studies have shown that acquisition of MDR is accompanied by up-regulation of lipids and proteins that constitute lipid rafts and caveolar membranes, notably glucosylceramide and caveolin. These changes may be related to the fact that in MDR cells a significant fraction of cellular P-gp is associated with caveolin-rich membrane domains, they may be involved in drug transport and they could have an impact on drug-induced apoptosis and on the phenotypic transformation of MDR cancer cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026553626537
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  • 7
    Electronic Resource
    Electronic Resource
    Transformation of Brassica juncea (L.) Czern with bacterial codA gene enhances its tolerance to salt stress (2000)
    Springer
    Molecular breeding 6 (2000), S. 489-499 
    Details
    ISSN: 1572-9788
    Keywords: Choline oxidase ; glycinebetaine ; transformation ; Brassica juncea ; salt stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The codA gene for biosynthesis of glycinebetaine from Arthrobacter globiformis was used for transforming Brassica juncea cv. Pusa Jaikisan (which lack any means to synthesize glycinebetaine) through Agrobacterium mediated transformation. The stable insertion of the codA gene in the shoots obtained on medium with kanamycin and hygromycin was confirmed by PCR analysis of the nptII gene. Southern hybridization with a codA probe further demonstrated its successful integration. Immunoblot analysis revealed the presence of choline oxidase demonstrating that the bacterial codA gene had been successfully transcribed and translated. The seeds of transgenic lines showed enhanced capacity to germinate under salt stress as compared to that of the wild type. Further, the seedlings of transgenic plants that expressed codA gene showed significantly higher growth than that of the wild type under salt stress conditions. These results demonstrated that the introduction of a biosynthetic pathway for glycinebetaine into Brassica juncea significantly enhanced their salt tolerance. Hence, homozygous genotypes of selected transformed lines can be exploited for improving the salt tolerance of the desirable cultivars of Brassica juncea through breeding programmes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026542109965
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  • 8
    Electronic Resource
    Electronic Resource
    Field resistance to Tomato spotted wilt virus in transgenic peanut (Arachis hypogaea L.) expressing an antisense nucleocapsid gene sequence (2000)
    Springer
    Molecular breeding 6 (2000), S. 227-236 
    Details
    ISSN: 1572-9788
    Keywords: antisense DNA ; co-transformation ; nucleocapsid gene ; pathogen-derived resistance ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Peanut (Arachis hypogaea L.) lines transgenic for the antisense nucleocapsid (N) gene of a Tomato spotted wilt virus (TSWV) strain isolated from peanut were generated by microprojectile-mediated transformation of repetitive somatic embryos of cultivars VC1 and AT120. The selectable marker (hygromycin resistance) and the N gene were on separate plasmids. A total of 207 VC1 and 120 AT120 hygromycin-resistant lines were produced. Of all the VC1 plants recovered 71% were cotransformed with the N gene (N+), but all plants were sterile. For AT120, 48 of the transgenic cell lines converted into plants. Polymerase chain reaction (PCR) screening showed 15 of the lines were transgenic for the N gene (N+), and two of these lines were fertile. A field test was conducted in 1998 at Ashburn, GA, using seeds from each fertile line, along with segregated and non-transgenic controls. Plants from four randomly selected field plots were examined for symptoms and analyzed by double-antibody sandwich enzyme-linked immunoabsorbent assay and PCR at 10 and 14 weeks after planting. At 14 weeks, 76% of the N+ plants were symptomless, while 2% were severely symptomatic or dead. In contrast, only 42% of the plants lacking the N gene were symptomless and 50% were severely symptomatic or dead. Northern blot analysis of selected field-resistant plants detected transgene RNA, and the transcript level appeared undiminished after viral exposure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009649408157
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  • 9
    Electronic Resource
    Electronic Resource
    Insect- and herbicide-resistant transgenic eucalypts* (2000)
    Springer
    Molecular breeding 6 (2000), S. 307-315 
    Details
    ISSN: 1572-9788
    Keywords: bar ; cry3A ; Eucalyptus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transgenic Eucalyptus camaldulensis containing both the insecticidal cry3A gene and the bar gene (conferring tolerance to the herbicide glufosinate ammonium) have been produced by Agrobacterium tumefaciens-mediated transformation of seedling explants. Transgenic plants from two lines tested were resistant to first instars of chrysomelid beetles that are important pests of commercial Australian eucalypt plantations. Both lines also exhibit tolerance to the broad-spectrum herbicide Liberty® at 6 l/ha (1.2 kg active ingredient per hectare), twice the field application rate. Transgenic insect- and herbicide-resistant eucalypts like these are likely to provide better insect and weed control options in plantations, particularly during the vulnerable establishment phase, provided that any adverse ecological impacts of releasing transgenic trees into the environment can be assessed and minimized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009676214328
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  • 10
    Electronic Resource
    Electronic Resource
    Transformation of Japanese persimmon (Diospyros kaki Thunb.) with a bacterial gene for choline oxidase (2000)
    Springer
    Molecular breeding 6 (2000), S. 501-510 
    Details
    ISSN: 1572-9788
    Keywords: choline oxidase ; glycinebetaine ; Japanese persimmon ; salt tolerance ; transformation ; woody plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This report describes the first successful genetic engineering of tolerance to salt in an agriculturally important species of woody plants by Agrobacterium-mediated transformation with the codA gene of Arthrobacter globiformis. This gene encodes choline oxidase, which catalyzes the oxidation of choline to glycinebetaine. The binary plasmid vector pGC95.091, containing a kanamycin-resistance gene (nptII), a gene for β-glucuronidase (gusA) and the codA gene in its T-DNA region, was used with a disarmed strain of Agrobacterium tumefaciens, EHA101, to transform Japanese persimmon (Diospyros kaki Thunb. `Jiro') by the leaf disk transformation method. The pRS95.101 plasmid that included only nptII and gusA in the T-DNA region was used as a control. We selected eight transgenic lines with one or two copies of the T-DNA after transformation with pGC95.091 (PC lines) and three lines after transformation with pRS95.101 (PR lines). The eight PC lines produced choline oxidase and glycinebetaine whereas neither was found in untransformed `Jiro' and in the control PR lines. Transgenic plants grew normally, resembling wild-type plants both in vitro and ex vitro. The activity of photosystem II in leaves of the transgenic Japanese persimmon plants under NaCl stress was determined in terms of the ratio of the variable (F v) to the maximum (F m) fluorescence of chlorophyll (F v/F m). The rate of decline in (F v/F m under NaCl stress was lower in the PC lines than in the control PR lines. These results demonstrated that genetic engineering of Japanese persimmon, which allowed it to accumulate glycinebetaine, enhanced the tolerance to salt stress of this plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026513831290
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  • 11
    Electronic Resource
    Electronic Resource
    Study of the factors influencing Agrobacterium-mediated transformation of pea (Pisum sativum L.) (2000)
    Springer
    Molecular breeding 6 (2000), S. 185-194 
    Details
    ISSN: 1572-9788
    Keywords: Agrobacterium ; transformation ; pea ; Pisum sativum L. ; PCR analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Factors influencing the efficiency of Agrobacterium-mediated transformation of pea were tested using highly efficient, direct regeneration system. The virulence of three Agrobacterium strains (octopine LBA 4404, nopaline C58C1 and succinamopine, hypervirulent EHA 105) clearly varied giving 1 transgenic plant per 100 explants for LBA 4404, 2.2 for C58C1 and 8.2 for EHA 105. To test the efficacy of selection agents we used the hypervirulent EHA 105 strain carrying pGPTV binary vector with one of four different selection genes: nptII, hpt, dhfr or bar. The mean number of transgenic, kanamycin-resistant plants for two cultivars tested was 4.2 per 100 explants and was slightly higher than the number of phosphinothricin-resistant plants (3.6 plants per 100 explants). The proportion of transgenics among kanamycin-selected plants was also higher than among phosphinothricin-resistant plants (35% and 28% respectively). There was no regeneration on hygromycin or methotrexate media (transformation with hpt and dhfr genes). Acetosyringone had no apparent influence on efficiency of transformation with hypervirulent EHA 105 strain, however it did affect the rate of transformation when moderately virulent C58C1 was used. Recovery of transgenic plants was enhanced after application of 5-azacytidine. The presence of integrated T-DNA was checked by PCR and confirmed by Southern hybridization. T-DNA was stably transmitted to the next generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009679908948
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  • 12
    Electronic Resource
    Electronic Resource
    Generation of transgenic wheat (Triticum aestivum L.) for constitutive accumulation of an Aspergillus phytase (2000)
    Springer
    Molecular breeding 6 (2000), S. 195-206 
    Details
    ISSN: 1572-9788
    Keywords: heterologous protein accumulation ; phytate phosphorus digestibility ; phytase ; phytic acid ; transformation ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Aspergillus niger phytase-encoding gene (phyA) has been constitutively expressed in wheat. Transgenic wheat lines were generated by microprojectile bombardment of immature embryos, using the bar-Bialaphos selection system. The bar and the phyA gene expression were controlled by the maize ubiquitin-1 promoter. To ensure secretion and glycosylation of the microbial phytase, an expression cassette was designed (Ubi-SP-Phy) where an α-amylase signal peptide sequence was inserted between the promoter and the phytase coding region. A similar cassette was constructed without the signal peptide sequence (Ubi-Phy). Five lines of fertile wheat transformed with the Ubi-SP-Phy were generated and two lines with the Ubi-Phy construct. The inheritance of the phyA gene was monitored through three generations. Western blotting of leaf and seed derived protein revealed the presence of an immunoreacting polypeptide of the size expected for the Aspergillus phytase. Up to 25 days after pollination, the heterologous phytase was exclusively present in the pericarp-seed coat-aleurone fraction. Thereafter, it accumulated in the endosperm in amounts exceeding that found in the seed coat and aleurone. The phyA mRNA and derived protein could at no stage be detected in the embryo. The Ubi-SP-Phy transgenic seeds exhibited up to 4-fold increase of phytase activity while up to 56% increase was found in Ubi-Phy plants. It is concluded that a functional Aspergillus phytase can be produced in significant amounts in wheat grains. This may be of relevance for improving the phytate-phosphorus digestibility when wheat grains are used for non-ruminant animal feed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009690730620
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  • 13
    Electronic Resource
    Electronic Resource
    Metamorphosis of a Non-Functioning Pituitary Adenoma to Cushing's Disease (2000)
    Springer
    Pituitary 3 (2000), S. 117-122 
    Details
    ISSN: 1573-7403
    Keywords: Cushing's disease ; silent ; pituitary ; tumour ; macroadenoma ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Silent pituitary adenomas occur in 25–40% of all clinically apparent pituitary tumours. However, the subsequent development of florid Cushing's disease in a patient with a previous non-functioning tumour is extremely rare. We describe a 47 year-old woman presenting initially with a large, invasive and recurrent, non-functioning pituitary tumour. Histopathologic study of the initial tissue did not stain for any hormones. Six years after the initial presentation, she manifested florid ACTH dependent Cushing's syndrome. A recurrent invasive pituitary macroadenoma necessitated a third transphenoidal surgery. The resected specimen, in this instance, revealed positive staining for ACTH, FSH, prolactin, and growth hormone on immunocytochemistry. An incomplete response to surgical, radiation and medical therapy necessitated a bilateral adrenalectomy to control the hypercortisolism, which resulted in remarkable clinical improvement. We also review five previous case reports from the revision literature of similar transformations from non-secreting pituitary adenomas to Cushing's disease. This subset of patients may represent yet another entity in the widening spectrum of Cushing's syndrome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009961925780
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  • 14
    Electronic Resource
    Electronic Resource
    Transforming Self and Society: A "Critical Appreciation" Model (2000)
    Springer
    Systemic practice and action research 13 (2000), S. 475-501 
    Details
    ISSN: 1573-9295
    Keywords: reflection ; transformation ; self-society dynamics ; critical systems thinking ; systemic intervention ; critical self-reflection ; ideology-critique ; critical appreciation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology
    Notes: Abstract This paper sets out to uncover some relationships between reflection, discourse and action. By challenging and synthesizing some polemical arguments concerning the creation, maintenance, and transformation of self and society, a model of self-society dynamics that operates through reflection, discourse, and action is developed. The model of self-society dynamics brings together aspects of self-reflection and ideology-critique (explored in the paper), which it is suggested are required for any intervention (transformative action) to be grounded in locally meaningful ways. By creating a dialog community in which self- and group assumptions can be subjected to validation through discourse, it is proposed that a dynamic balance between individual needs and broader societal aims may be achieved. If individuals can be open to such discourse (i.e., they can become critically self-reflective), then it is argued that possibilities for achieving sustainable change will be significantly enhanced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009541430809
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  • 15
    Electronic Resource
    Electronic Resource
    Factors involved in Agrobacterium tumefaciens-mediated gene transfer into Pinus nigra Arn. ssp. salzmannii (Dunal) Franco (2000)
    Springer
    Euphytica 114 (2000), S. 195-203 
    Details
    ISSN: 1573-5060
    Keywords: conifers ; salgareño pine ; tissue culture ; transformation ; transient gene expression ; uidA expression ; vir gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cotyledons from dissected sterile embryos of salgareño pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) were inoculated with different disarmed Agrobacterium tumefaciens strains harbouring the binary vector p35SGUSint. The transient expression of a β-glucuronidase gene (uidA) was studied, using a histochemical staining procedure. Nineteen days after inoculation, the activity of β-glucuronidase was detected in epidermal and subepidermal layers of cotyledonary explants. The EHA105 strain harbouring a disarmed agropine-type Ti-plasmid (pTiBO542) was the most effective for gene transfer of the uidA gene. The effects of exudates and extracts from 0-day-old embryos on induction of vir gene expression in A. tumefaciens were also examined. The results of this study showed that salgarño pine embryo exudates contain a substance(s) that induce vir gene expression, in similar way to that observed with 100 μM acetosyringone (AS).All these findings suggest that T-DNA processing and transfer might take place when Agrobacterium infects suitable tissues of salgareño pine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003946131356
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  • 16
    Electronic Resource
    Electronic Resource
    Towards genetic transformation in the monocot Alstroemeria L. (2000)
    Springer
    Euphytica 115 (2000), S. 17-26 
    Details
    ISSN: 1573-5060
    Keywords: cell suspension ; monocotyledon ; selection ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The successful application of plant biotechnology to Alstroemeria improvement will largely depend on the availability of an efficient regeneration/transformation system. Regeneration in Alstroemeria is accomplished from nodular embryogenic callus initiated from zygotic embryos. Histological studies of embryogenic callus initiation from 4-weeks old cultured ovules revealed that the outermost layers of the protoderm of the embryogenic nodules divided to form either a new nodule or aproembryo. Transient gene expression after particle bombardment of nodular embryogenic callus was optimized using DNA of pAHC25. The highest β-glucuronidase expression was found when the GUS gene was under control of the maize ubiquitin promoter, the target tissue was placed 5 cm below the microcarrier launch assembly and when the rupture disc-breakage point was between 650–900 psi. Kanamycin blocked regeneration of somatic embryos, however, did not block growth of nodular embryogenic callus. With phosphinothricin both callus growth and regeneration were blocked. Bombardment of nodular embryogenic callus with DNA of pAHC25 combined with selection on medium containing phosphinothricin resulted in putative transgenic chimeric. Friable calli were selected from nodular embryogenic callus and used to initiate suspensions. These cell suspensions were subjected to transformation by particle bombardment using DNA of pAHC25 and resulted in a stable transformed friable callus line after selection based on luciferase activity. Even after 2 years of maintenance this callus line was luciferase positive and the Polymerase Chain Reaction analysis demonstrated the presence of the introduced gene in this friable callus line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003979423469
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  • 17
    Electronic Resource
    Electronic Resource
    Rapid transformation and regeneration of alfalfa (Medicago falcata L.) via direct somatic embryogenesis (2000)
    Springer
    Plant growth regulation 31 (2000), S. 155-166 
    Details
    ISSN: 1573-5087
    Keywords: alfalfa ; cell division cycle ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two simple, rapid and efficient protocols for theregeneration of transformed tetraploid lines ofalfalfa (Medicago falcata L.) have beendeveloped and compared. Leaf explants fromembryogenic lines 47/1-150 and 47/1-5 were inoculatedwith Agrobacterium tumefaciens containingconstructs carrying the nptII selectable markergene and promoter:gusA gene fusions under thecontrol of the CaMV 35S or Arabidopsis cdc2a,CycB1 and CycA2 promoters. In the firstregeneration system (the MSH system), inoculated leafexplants were incubated on MS medium supplemented with2,4-D and kinetin and then subcultured onto plantgrowth regulator-free MS medium in order to inducedirect somatic embryogenesis. In the secondregeneration system (the B5h system), the inoculatedexplants were incubated on B5h medium to induceindirect production of somatic embryos viaembryogenic callus. In both systems, an effectivekanamycin selection regime was employed and wasmaintained when the embryos were subcultured onto arecovery medium (Boi2Y) to promote further embryodevelopment. The use of Boi2Y medium was particularlyimportant for shortening the regeneration time andpromoting a higher frequency of healthy plantletproduction from the somatic embryos. The maturesomatic embryos were finally transferred to plantgrowth regulator-free MS medium for plantletformation. Transgenic plantlets were produced within10–14 weeks in the MSH system and 12–16 weeks in theB5h system. The MSH system appears to be the fastesttransformation system reported for leguminous speciesto date. Confirmation of transformation was obtainedusing a re-callusing assay on kanamycin and subsequentSouthern blot hybridisation and PCR analysis. Theability to induce expression of GUS activity in leafexplants containing the cell division cycle genepromoter:gusA constructs by 2,4-D treatment alsoproved to be a reliable indicator of transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006306909722
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  • 18
    Electronic Resource
    Electronic Resource
    Agrobacterium-mediated sorghum transformation (2000)
    Springer
    Plant molecular biology 44 (2000), S. 789-798 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; sorghum ; transformation ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a `Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transformation experiments. A number of different transformation conditions were tested and a total of 131 stably transformed events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on transformation efficiency, with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably transformed sorghum plants. The Agrobacterium method we used yields a higher frequency of stable transformation that other methods reported previously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026507517182
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  • 19
    Electronic Resource
    Electronic Resource
    A computational procedure for joining separate map sheets (2000)
    Springer
    GeoJournal 52 (2000), S. 253-262 
    Details
    ISSN: 1572-9893
    Keywords: map sheets ; GIS ; seamless spatial database ; transformation ; computational procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Map sheets have been often used as a basic spatial unit for managing spatial data produced from paper maps. This often results in incompatibility between adjacent map sheets, because spatial objects do not cross the boundaries smoothly and even the boundaries themselves do not match their neighbors exactly. To solve the problem this paper proposes a computational procedure for joining separate map sheets to obtain seamless spatial data. Line objects digitized separately in different map sheets are considered, which are frequently used to represent road networks, gas pipelines, and boundaries of polygon objects. The procedure consists of three steps: (1) extraction of end nodes, (2) detection of matching nodes, and (3) transformation of the map sheet. Each step goes interactively so that unexpected errors can be avoided by human observation. To test the validity of the procedure, map sheets are combined containing the road network data of Tokyo 23-ku area, Japan.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1014224325346
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  • 20
    Electronic Resource
    Electronic Resource
    The changing geography of morbidity and mortality in post-communist Poland (2000)
    Springer
    GeoJournal 50 (2000), S. 97-100 
    Details
    ISSN: 1572-9893
    Keywords: disease ; health ; morbidity ; mortality ; pollution ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract In general, the health of Poles improved markedly in the thirty years after the Second World War, but there was some deterioration after 1989 before improvement resumed. Only in the case of cancer is there an upward trend and so Poles are now healthier than they have been at any time in the past. However there are sharp regional variations well exemplified by the incidence of tuberculosis, where there appears to be some correlation with poorer housing and atmospheric pollution. High death rates in Lodz (consistently the highest in the country at the voivodship level between 1989 and 1996), may also be linked with environmental pollution as well as the ageing of the population. Variations between town and country are small, but Poland shows up in a poor light when compared with other European countries. These are important issues for the administration and financing of the welfare services.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007127431508
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  • 21
    Electronic Resource
    Electronic Resource
    Socioeconomic transformation in rural Romania through the eyes of experts: Demographic and social issues (2000)
    Springer
    GeoJournal 50 (2000), S. 151-155 
    Details
    ISSN: 1572-9893
    Keywords: demography ; experts ; rural ; Romania ; rural development ; social issues ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract There is no standard model of transformation for post- socialist countries and each country encounters specific problems rooted in the geographical characteristics of the areas concerned. The human resources are of the greatest importance because it really matters how people (especially the decision-makers) perceive system change and continually reformulate their expectations and strategies; so investigations into the views of people caught up in the transformation can provide a deeper understanding of the background to structural change. Working the national, regional level and local levels in Romania, experts were asked to consider the advantages and disadvantages arising out of the transformation, the most important problems and constraints for future rural development and the policies needed. The paper examines the responses on demographic and social issues. It emerges the most detailed responses were supplied by local-level representatives while respondents at the regional level steered a middle course between the need to address local problems and the prime importance of stimulating the Romanian economy so as to generate resources for welfare programmes (with the latter issue the overriding concern of interviewees at national level). There was general agreement on the importance of foreign investment and European integration for economic development, with local actors taking only small steps in line with the existing opportunities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007120608735
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  • 22
    Electronic Resource
    Electronic Resource
    The effect of DNA/gold particle preparation technique, and particle bombardment device, on the transformation of barley (Hordeum vulgare) (2000)
    Springer
    Euphytica 111 (2000), S. 67-76 
    Details
    ISSN: 1573-5060
    Keywords: Barley ; Hordeum vulgare ; transformation ; particle bombardment ; particle gun
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Immature embryos of the spring barley variety GoldenPromise, were bombarded with three different particledelivery systems and both transient and stabletransformation examined. In addition, a range oftechniques for the preparation of the DNA coated goldparticles was examined. Fertile transgenic barleyplants were obtained using three particle preparationtechniques which differed in the amount of gold andDNA used for each bombardment. However, only one ofthe particle delivery systems, the PDS 1000/He device,appeared to be effective in yielding transformedbarley plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003700300235
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  • 23
    Electronic Resource
    Electronic Resource
    Enhanced forskolin production in genetically transformed cultures of Coleus forskohlii by casein hydrolysate and studies on growth and organisation (2000)
    Springer
    Biotechnology letters 22 (2000), S. 133-136 
    Details
    ISSN: 1573-6776
    Keywords: casein hydrolysate ; Coleus forskohlii ; forskolin ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Casein hydrolysate at 2.0 g l−1 significantly enhanced forskolin content (2.3 mg g−1 cell dry wt) in a rhizogenic tumourous line, GCO-RCH-2 of Coleus forskohlii. In rooty teratoma line, RC-ST-2/4, forskolin content enhanced to 1.7 mg g−1 cell dry wt in presence of 2.5 g l−1 casein hydrolysate. Unlike untransformed calli and rhizogenic/root cultures, all the forskolin yielding transformed cultures of C. forskohlii have been maintained for over 5 years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005618307074
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  • 24
    Electronic Resource
    Electronic Resource
    Two types of new algorithms for finding explicit analytical solutions of nonlinear differential equations (2000)
    Springer
    Applied mathematics and mechanics 21 (2000), S. 1423-1431 
    Details
    ISSN: 1573-2754
    Keywords: nonlinear differential equations ; transformation ; algorithm ; analytical solution ; O175.29
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract The idea of AC=BD was applied to solve the nonlinear differential equations. Suppose that Au=0 is a given equation to be solved and Dv=0 is an equation to be easily solved. If the transformation u=Cv is obtained so that v satisfies Dv=0, then the solutions for Au=0 can be found. In order to illustrate this approach, several examples about the transformation C are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02459221
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  • 25
    Electronic Resource
    Electronic Resource
    Metal resistance in Pseudomonas strains isolated from soil treated with industrial wastewater (2000)
    Springer
    World journal of microbiology and biotechnology 16 (2000), S. 177-182 
    Details
    ISSN: 1573-0972
    Keywords: Conjugation ; metal resistance ; plasmid DNA ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Heavy metal concentrations in soil treated with industrial wastewater of Aligarh City (U.P.), India were determined. The analysis of test samples revealed high levels of Fe, Zn, Ni and Cu. A total of 45 Pseudomonas spp. were isolated from soil and were characterized on the basis of morphological, cultural and biochemical characteristics. MICs of Hg2+, Cd2+, Cu2+, Cr3+, and Zn2+ for each isolate were determined. Eighty percent of the strains isolated from soil harboured resistance to copper, whereas 73.3% of the isolates exhibited resistance to cadmium, 71.1% to chromium and zinc and 48.8% to mercury. A maximum MIC of 200 μg/ml for mercury and 1600 μg/ml for other metals was observed. Metal resistance was found to be plasmid mediated as evidenced by transformation studies. Further, the transmissible nature of chromium resistance was confirmed by conjugation. Agarose gel electrophoresis using the miniprep method for plasmid isolation revealed that these isolates harboured plasmids of molecular weights (45 & 47 kb) using EcoRI and HindIII digests of λDNA and undigested λDNA as standard markers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008905902282
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  • 26
    Electronic Resource
    Electronic Resource
    Bringing “The Dead” to Life: Reading James Joyce (2000)
    Springer
    Journal of applied psychoanalytic studies 2 (2000), S. 109-115 
    Details
    ISSN: 1573-3459
    Keywords: James Joyce ; “The Dead” ; fiction ; reading ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract The author offers a personal reading of James Joyce's “The Dead.” She focuses on how the sounds of the language are used to portray the main character's deadness and his beginning to come to life once the barriers to inner self and self-knowledge are broken.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010193724350
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  • 27
    Electronic Resource
    Electronic Resource
    Transformation of batridene (2000)
    Springer
    Chemistry of natural compounds 36 (2000), S. 137-139 
    Details
    ISSN: 1573-8388
    Keywords: 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid ; transformation ; DMSO
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Transformations of 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid (batridene) in DMSO are studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02236415
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  • 28
    Electronic Resource
    Electronic Resource
    Intercellular communication and the control of growth: XI. Alteration of junctional permeability by thesrc gene in a revertant cell with normal cytoskeleton (1984)
    Springer
    The journal of membrane biology 82 (1984), S. 207-212 
    Details
    ISSN: 1432-1424
    Keywords: cell-to-cell communication ; cell-to-cell channel ; cell junction ; communicating junction ; gap junction ; Rous sarcoma virus ; transformation ; cancer ; growth control ; tyrosine phosphorylation ; src gene ; protein kinase ; pp60src ; cytoskeleton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary To learn whether the reduction of cell-to-cell communication in transformation is a possible primary effect of pp60src phosphorylation or secondary to a cytoskeletal alteration, we examined the junctional permeability in transformed cells with normal cytoskeleton. The permeability to fluorescentlabelled mono- and diglutamate was compared in clones of Faras' vole cells—clones transformed by Rous sarcoma virus and reverted from that transformation. One revertant clone (partial revertant), had the high levels of pp60src kinase activity and tumorigenicity of the fully transformed parent clone, but had lost the cytoskeletal alterations of that clone. Another revertant clone (full revertant) had lost the tumorigenicity and most of the pp60src kinase activity, in addition (J.F. Nawrocki et al., 1984,Mol. Cell Biol. 4:212). The junctional permeability of thepartial revertant with normal cytoskeleton was similar to that of the fully transformed parent clone with abnormal cytoskeleton. The permeabilities of both were lower than those of thefull revertant and the normal uninfected cell, demonstrating that the junctional change by thesrc gene is independent of the cytoskeletal one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01871630
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  • 29
    Electronic Resource
    Electronic Resource
    Intercellular communication and the control of growth: X. Alteration of junctional permeability by thesrc gene. A study with temperature-sensitive mutant Rous sarcoma virus (1984)
    Springer
    The journal of membrane biology 82 (1984), S. 191-205 
    Details
    ISSN: 1432-1424
    Keywords: cell junction ; cell-to-cell communication ; cell-to-cell channel ; gap junction ; Rous sarcoma virus ; transformation ; cancer ; growth control ; tyrosine phosphorylation ; src gene ; protein kinase ; pp60src
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary To study changes of junctional membrane permeability associated with transformation, the junctions and the nonjunctional membranes of quail embryo-, chick embryo- and mouse-3T3 cell cultures, infected with temperature-sensitive mutant Rous sarcoma virus, were probed with fluorescent-labelled glutamate. Junctional permeability fell in the transformed state. In the quail cells, the fall was detectable within 25 min of shifting the temperature down to the level (permissive) at which tyrosine-phosphorylation by the viralsrc gene product is expressed. This reduction of junctional permeability is one of the earliest manifestations of viral transformation. Normal permeability was restored within 30 min of raising the temperature to the nonpermissive level, a reversibility that could be displayed several times during the span of a cell generation. The reversal seems to reflect a reopening of cell-to-cell channels rather than a synthesis of new ones; it is not blocked by protein-synthesis inhibition. Treatments with cyclic AMP and phosphodiesterase inhibitor or with forskolin, which stimulate serine and threonine phosphorylation—the type of phosphorylation on which normal junctional permeability depends (Wiener & Loewenstein, 1983,Nature 305∶433)—did not abolish, in general, the junctional effect of the virus;src tyrosine-phosphorylation apparently overrides the junctional upregulation mediated by cyclic AMP. Nonjunctional membrane permeability was not sensibly affected by the virus. It was affected, however, by temperature: lowering the temperature from the nonpermissive to the permissive level caused the nonjunctional permeability to fall, andvice versa. This change was unrelated to transformation. Its secondary effect on junctional transfer is in the opposite direction to that produced by the temperature-activated viral transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01871629
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  • 30
    Electronic Resource
    Electronic Resource
    Intercellular communication and the control of growth: XII. Alteration of junctional permeability by simian virus 40. roles of the large and smallT antigens (1984)
    Springer
    The journal of membrane biology 82 (1984), S. 213-220 
    Details
    ISSN: 1432-1424
    Keywords: cell junction ; cell-to-cell communication ; cell-to-cell channel ; gap junction ; simian virus 40 ; DNA virus ; tumor antigens ; transformation ; cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary We studied the action of temperature-sensitive mutant simian virus 40—a transformation-inducing DNA virus—on the junctional permeability to mono-, di- and triglutamate in rat embryo-, pancreas islet (epithelia)-, and 10T1/2 cell cultures. Junctional permeability was reduced (reversibly) in the transformed state. To dissect the genetics of this alteration, we used two kinds of mutant virus DNA. One kind had a temperature-sensitive mutation on theA gene, rendering the largeT antigen (the gene product) thermolabile (T + ⇆T −). The other had a deletion on theF gene, in addition, abolishing (permanently) the expression of the littlet antigen (t −). The junctional alteration occurred in the conditionT + t +, but not in the conditionsT − t +,T + t − orT − t −. Both antigens, thus, are necessary for this junctional alteration—a genetic requirement identical to that for decontrol of growth (but distinct from that of the cytoskeletal alteration).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01871631
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  • 31
    Electronic Resource
    Electronic Resource
    Invasiveness of transformed bladder epithelial cells (1984)
    Springer
    Cancer and metastasis reviews 3 (1984), S. 265-296 
    Details
    ISSN: 1573-7233
    Keywords: bladder cells ; urothelial cell lines ; markers for invasiveness ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The invasiveness of bladder tumors has been studied in man, experimental animals, and in tissue culture by numerous authors. The prognostic importance of cellular markers for invasiveness is stressed, and the usefulness of histopathological and cytologic grading, cytogenetic studies, antigenic investigations, and enzymatic characterization is discussed. The invasiveness of bladder cells has frequently been examined in transplantation and explantation experiments. In human urothelial cell cultures three grades of transformation are defined, and a correlation has been established between the invasiveness of these cell lines in a three-dimensional in vitro model and their tumorigenicity in nude mice. The mechanism of tumor invasion is discussed, and it is recommended in future research to make a distinction between invasion en bloc and cellular infiltration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048389
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  • 32
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    Electronic Resource
    Presence of a plant cell wall is not required for transformation of Nicotiana by Agrobacterium tumefaciens (1984)
    Springer
    Plant cell, tissue and organ culture 3 (1984), S. 175-188 
    Details
    ISSN: 1573-5044
    Keywords: Agrobacterium tumefaciens ; crown gall ; transformation ; lysopine dehydrogenase ; cell wall ; cell cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Agrobacterium has been used to transform zero to six-day-old cell wall nonregenerating (CWNR) and cell wall regenerating (CWR) leaf protoplasts of tobacco. Transformed cells were selected by phoytohormone autotrophic growth and were verified by detection of the presence of lysopine dehydrogenase. Transformation frequencies in CWNR protoplasts were at least as high as those in CWR protoplasts, indicating that a plant cell wall is not required for the process of crown gall tumorigenesis. Transformation frequencies were highest in two-day-old protoplasts. This age coincides with the onset of DNA synthesis and the first mitosis within the cell populations. We suggest that the initiation of cell cycle activity may be important for the transformation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00033739
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  • 33
    Electronic Resource
    Electronic Resource
    Electronic structure of the PdCl42- and PtCl42-ions (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 201-209 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electronic spectra of PdCl42- and PtCl42- are studied by quantum-chemical methods with the ultimate object being to understand the differences in reactivity for Pt(II) and Pd(II) complexes. Nonrelativistic ab initio UHF, DV - Xα, and MSXα methods give very similar assignments of the spectra for PdCl42-. The d-d spectrum for PtCl42-, which is very different from the d-d spectrum of PdCl42-, agrees qualitatively with the spectra obtained using the relativistic extended-Hückel (REX) and Dirac-Slater (DS) methods. Although the latter two methods disagree somewhat in the interpretation of the high intensity bands in PtCl42-, it appears reasonable to interpret at least one of the lines as a 5d → 6p transition.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250116
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  • 34
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    Electronic Resource
    Spin-orbit excitation in the system I + I2: Relativistically parameterized extended-Hückel calculationsPresented at the Symposium on Relativistic Effects in Quantum Chemistry, Åbo Akademi, Finland, June 21-23, 1982. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 223-231 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relativistically parameterized extended-Hückel (REX) calculations concerning species and exchange reactions in the system I or I* + I2 are reported, where I = 2P3/2 and I* = 2P1/2. From their experimental data for related halogen systems X + YZ XY + Z, E. B. Gordon, A. I. Nadkhin, S. A. Sotnichenko, and I. A. Boriev [(Chem. Phys. Lett. 86, 209 (1982)] have proposed a conservation rule for the spin-orbit state (X* → Z*, X → Z). The results of REX calculations, double-group symmetry analysis, and schematic state correlation diagrams reported here are consistent with the proposed conservation rule. Two of the transition states are linear and the third nearly so, but no Γ1/2-Γ3/2 crossings leading to spin-orbit conversion are found.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250118
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  • 35
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    Electronic Resource
    Relativistic studies of atoms and ions with complex configurationsPresented at the Symposium on Relativistic Effects in Quantum Chemistry, Åbo Akademi, Finland, June 21-23, 1982. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 47-55 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The method of the relativistic investigation of the energy spectra and the electronic transitions in the case of complex configurations, based on the theory of the irreducible tensorial operators and the genealogical coefficients, is described. The use of the quasispin and isospin technique in the relativistic approximation is discussed. Expressions are presented for electric multipole transition probabilities for general values of the gauge condition of electromagnetic field potential.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250105
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  • 36
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    Relativistic atomic structure theory: Some recent workPresented at the symposium on Relativistic Effects in Quantum Chemistry, Åbo Akademi, Finland, June 21-23, 1982. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 23-46 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent developments in relativistic atomic structure have been more in terms of program improvement than in fundamental theory. Some comments on both aspects of this work are illustrated by a description of two different recent applications. In the first, we study the contribution of the interaction of relativity and correlation to the 2 3S-2 3P0,1,2 intervals in heliumlike ions, whose theoretical estimation is important for testing QED. The study of satellite structure in the Kβ x-ray emission spectrum of Ar illustrates a quite different use of the program packages developed at Oxford for investigating configuration interaction. The use of shake theory to predict the initial states, populated along with the primary vacancy giving rise to the diagram line, gives a satellite line intensity distribution which agrees very well with recent experimental spectra.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250104
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  • 37
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    Electronic Resource
    Isospin basis for atoms in relativistic approximationPresented at the Symposium on Relativistic Effects in Quantum Chemistry, Åbo Akademi, Finland, June 21-23, 1982. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 57-62 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The isospin basis is put into operation for investigation of atomic configurations, having two shells of equivalent electrons, characterized by the same orbital (LS coupling) or total (jj coupling) angular momenta of each electron. Tensorial properties of both the operators and the wave functions are studied in this basis. The two-particle operator is expressed in terms of the tensors irreducible in the isospin space. The problem of the additional classification of the levels is considered. The accuracy of the quantum numbers of the isospin basis in jj coupling scheme is discussed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250106
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  • 38
    Electronic Resource
    Electronic Resource
    Use of the S-matrix in the relativistic treatment of resonance energy transfer (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 79-96 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The S-matrix formalism is used to treat the phenomenon of resonance energy transfer (sensitized fluorescence). It is shown that for dipole-allowed transitions and short sensitizer-acceptor separations, the relativistic treatment yields the same result as the nonrelativistic Perrin-Förster theory. For large sensitizer-acceptor separations, long-range coupling terms appear in the relativistic treatment. Resonance energy transfer through these long-range coupling terms is compared with spontaneous photon emission, and direct-interaction theories of electromagnetism are discussed. In the Appendix it is shown that the relativistic theory predicts resonance transfer of triplet excitation energy through the spin-spin coupling term in the Breit interaction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250110
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  • 39
    Electronic Resource
    Electronic Resource
    Relativistic calculations of dissociation energies and related properties (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 131-148 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods of calculation of potential energy curves or surfaces, including dissociation energies, bond distances, and vibration frequencies, are discussed as well as recently obtained results for several molecules. The ab initio relativistic methods involve the derivation of “shape-consistent” effective potentials from Dirac-Fock atomic calculations. These effective potentials are averaged and differenced with respect to spin with the differences, p3/2 - p1/2, etc., yielding spin-orbit operators. The molecular calculations are then set up in a familiar manner through the SCF stage using spin-averaged effective potentials. The final stage is a configuration-interaction calculation including the spin-orbit terms as well as the electron repulsion terms. Calculations that have been made for several low-lying excited states as well as the ground state for Au2, TlH, Tl2, Sn2, and Pb2 are reviewed. Good agreement is obtained with spectroscopic data and a number of interesting predictions are made.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560250113
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  • 40
    Electronic Resource
    Electronic Resource
    Relativistic corrections to the valence and conduction band edges of anisotropic semiconductors (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 263-263 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250120
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  • 41
    Electronic Resource
    Electronic Resource
    Announcement. International academy of quantum molecular sciences (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 273-273 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250121
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  • 42
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    Electronic Resource
    Groups of simple graphsPresented at the symposium on “Applications of Group Theory and Graph Theory to Chemistry,” Southeast/Southwest Regional Meeting, American Chemical Society, 1980. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 309-320 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The group structure of simple graphs can be found by factoring the adjacency matrix into cyclic blocks. The blocks correspond to permutational subgroups of the graph. The overall group structure is a product of the independent subgroups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250204
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  • 43
    Electronic Resource
    Electronic Resource
    Calculation of localized molecular orbitals (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 355-365 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two techniques are presented for reducing the effort required to determine localized orbitals based on the energy or density criteria. The first, population weighted editing of the electronic repulsion integrals, reduces the effort required for each iteration of the localization procedure. The second, damping/extrapolation of the transformation matrix, reduces the number of iterations required to reach convergence. Numerical results are provided for methane and formaldehyde (for the editing method) and for carbon monoxide and boron fluoride (for the damping/extrapolation technique).
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250208
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  • 44
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250301
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  • 45
    Electronic Resource
    Electronic Resource
    Calculation of systems involving strong delocalized bonds within a modified PCILO framework. I. Valence-bond PCILO method (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 475-481 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In describing mesomer structures by the original PCILO method several problems may occur because of the use of localized bonds. A so-called VB-PCILO including a superposition of several mesomer boundary structures in the CI perturbation treatment will be proposed.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560250303
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  • 46
    Electronic Resource
    Electronic Resource
    Vibrational-rotational levels of diatomic RKR potentials (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 677-686 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The vibration-rotation levels for the diatomic RKR potential curve are solved using both perturbational and variational approaches. To obtain any-order correction of the energy from unperturbed parameters, an iterative scheme is formulated in the hypervirial framework. Variational calculations are carried out upon a rotationless Morse oscillator basis set and using a transformation technique to treat the effective potential energy function. Numerical results for the RbH X 1Σ+ state are obtained. The accuracy of the energy levels is tested by solving the Schrödinger equation by a numerical procedure.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250406
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  • 47
    Electronic Resource
    Electronic Resource
    Bonding in alkali metal homonuclear diatomics (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 723-731 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analysis of the factors that contribute to the stability of the bond between alkali metal atoms is made by using nonorthogonal configuration interaction. Beyond the orbital size, the overlap of the valence orbitals of one atom with the core orbitals of the other accounts for most of the difference between the hydrogen molecule and the alkali metal diatomics. It is shown that the valence bond description does not provide a satisfactory description in any case except for the hydrogen molecule, and valence electron correlation using the p-type valence orbitals is essential.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250411
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  • 48
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250501
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  • 49
    Electronic Resource
    Electronic Resource
    Vibronic coupling of electronic states. IV. Harmonic CBO potentials with equal minima positions - the influence of different vibronic coupling strengths on the electronic absorption and emission spectra containing a longest-wavelength electronically forbidden transition (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 687-697 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of vibronic coupling between two harmonic CBO potentials with equal minima positions on the electronic absorption and emission spectra is investigated in the framework of our model using the variational procedure. The numerical results, being identical with those obtained through the vibronic coupling model of Fulton, Gouterman, and Brickmann, are discussed with regard to the longest-wavelength electronically forbidden transition, its vibrational structure, and the Stokes loss.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560250407
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  • 50
    Electronic Resource
    Electronic Resource
    Molecular orbital studies on the structure of nucleoside analogs. IV. Conformation of 3-deazapurine nucleosides (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 743-752 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational properties of 3-deazapurine nucleosides (namely, 3-deazaadenosine and 3-deazaguanosine) have been investigated by the PCILO method. Both C(2′)-endo and C(3′)-endo sugar puckers have been considered and the results indicate that the conformational preferences of these nucleoside analogs are quite different from those of their parent nucleosides adenosine and guanosine, respectively. This result has been correlated in terms of the biological inactivity of these nucleoside analogs.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250413
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  • 51
    Electronic Resource
    Electronic Resource
    Convergence problems in SCF calculations: Further applications of a new technique based on the use of inverse Fock operator (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 809-816 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A recently proposed orbital optimization technique based on the use of the inverse of the level-shifted Fock operator is successfully applied to a large number of pathologically divergent cases. The possibility of eliminating convergence problems by adopting a similar modification in the operation of the orthogonal gradient method is also successfully tested.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560250505
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  • 52
    Electronic Resource
    Electronic Resource
    The band structure of porphyrinatonickel(II). A semiempirical crystal orbital study based on the tight-binding formalism (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 817-851 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The band structure of porphyrinatonickel(II) (2) has been studied by means of crystal orbital calculations that are based on the tight-binding approximation; the computational framework is a recently developed INDO model for transition metal compounds of the 3d series. The porphyrinato polymer has been studied in an eclipsed arrangement (2a) and in a staggered conformation (2b) where neighboring layers are rotated by 41°. The total energy of the metallomacrocycle has been decomposed into one- and two-center contributions; the latter interaction parameters have been fragmented into physically feasible resonance, exchange, and classical electrostatic (electron-electron, electron-core, core-core) interactions. It is shown that individual two-center potentials between atoms in neighboring layers are prevailingly determined by the electrostatic interaction energy. The NiNi coupling in the chain is highly repulsive; important stabilizing interactions are predicted between the 3d center of one cell and the electronegative N atoms in the neighboring layers. Stabilizing and destabilizing electrostatic interaction potentials largely compensate each other; the net stabilization in the polymer comes from the accumulation of resonance and exchange increments. The unoxidized Ni(II) porphyrinato polymer is an insulator. Several ligand bands (π, σ, and lone-pair) are predicted on top of bands with significant Ni 3d admixtures; the conduction band of the unoxidized strand is of ligand π* character. The dense manifold of ligand states in the vicinity of the Ni 3d states (3dz2, 3dx2-y2, 3dxz/3dyz) prevents the formation of bands in the polymer that are strongly localized at the 3d center. Ni 3dz2 and 3dx2-y2 interact strongly with ligand lone-pair and σ states. Avoided crossings between ∊(k) curves in k space lead to compositions in the various bands that differ significantly at the bottom and the top. The INDO crystal orbital formalism predicts a partial oxidation of ligand bands in derivatives of 2 that contain oxidants (e.g., halides). The theoretical findings derived for 2 are compared with available experimental data on highly conducting porphyrinatonicke(II) polymers (tetrabenzo and octamethyltetrabenzo derivatives of 2).
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250506
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  • 53
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250601
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  • 54
    Electronic Resource
    Electronic Resource
    Calculation of bound-state energies from a variational functional method (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 1023-1033 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variational functional method is improved and generalized in order to obtain approximate bound-state energies of a wide variety of quantum-mechanical systems. Calculations on the discrete spectrum of the hydrogen atom in a magnetic field and the bounded harmonic oscillator show that the procedure is very promising.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250607
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  • 55
    Electronic Resource
    Electronic Resource
    A modified PCILO framework using the CNDO/Boyd-Whitehead parametrization (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984), S. 1055-1060 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The CNDO/BW modification of the CNDO/2 approximation was used within the PCILO framework. It was shown on some significant examples that all the good results of the original PCILO-CNDO/2 method can be reproduced by the modified version PCILO-CNDO/BW at least. Thus, preserving the quality of its results a computer-expense-reduced PCILO method is proposed for calculations on large molecular systems.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250610
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  • 56
    Electronic Resource
    Electronic Resource
    Ab initio Hartree-Fock approach to the study of polymers: Application to polyacetylenes (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 197-212 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ab initio Hartree-Fock method devoted to the study of polymers is presented, truncation criteria for the exchange and the Coulomb series are discussed, and it is shown that the error in the total energy evaluation can be reduced to below 0.0001 a.u./cell with little computational effort. Results for six polyacetylene isomers are presented and compared with previous ab initio data obtained using the same basis set. In agreement with the experimental findings, the alternating all-trans structure is the most stable.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260205
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  • 57
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    Electronic Resource
    Theoretical invstigations of the electronic states of porphyrins. I. Basis set development and predicted spectrum of pyrrole (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 237-250 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new minimum basis set was developed for use in computing excitation energies of large molecules. It is particularly suited to calculating ionization potentials and Rydberg transitions. Pyrrole excitation energies and oscillator strengths calculated with this basis set are compared to larger basis set ab initio and semiempirical results. The 6-eV band in the experimental spectrum is predicted to be the result of three Rydberg absorptions, with no underlying (π, π*) absorption. The calculations also provide an explanation for the observed N—H stretch in the 6-eV region.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260209
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  • 58
    Electronic Resource
    Electronic Resource
    Theoretical investigations of the electronic states of porphyrins. II. Normal and hyper phosphorus porphyrins (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 251-274 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio methods have been used to calculate the ground and excited states of “normal” and “hyper” porphyrins. Perturbation theory and CI methods were used to determine differential ground and excited-state correlation effects for [Pv(P)F2]+ and [PIII(P)]+. A comparison is made to the INDO/S/CI predicted wavefunctions and spectra and to the experimental spectra of closely related molecules. The “hyper” [PIII(P)]+ calculations show some very low energy electronic transitions which provide an explanation for an anomalous “red” band in the spectrum and for the lack of fluorescence. Ab initio calculations also predict that (1) the lowest energy 1A1 state is a two-configuration wavefunction which can be described as a diradical, (2) the two lowest-energy singlet excited states are double excitations from the closed shell SCF configuration, and (3) a 3B2 state is very close in energy to the lowest 1A1 state.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260210
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  • 59
    Electronic Resource
    Electronic Resource
    General harmonic oscillator integrals by the operator method (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 339-347 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The operator technique with a minimum of commutator algebra is employed to calculate matrix elements of any number of operators between distorted, displaced harmonic oscillator wavefunctions. The results are valid for multidimensional integrals, and regardless of the extent of the Duschinsky effect. General recursion relations useful in machine calculations are given. The formalism is illustrated for the well-known one-dimensional Franck-Condon integrals.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260304
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  • 60
    Electronic Resource
    Electronic Resource
    Localized molecular orbitals for multiple bonds in the ZDO approximation: The σ-π vs. banana bonds dilemma (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 383-403 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The multiple bond description supplied by localized molecular orbitals obtained within the ZDO approximation is analyzed. In particular, conditions for the appearance of σ-π separation and of continuous degeneracy of the localization sum against σ-π mixing are given for two current ZDO energy- and density-localization methods. Likewise, a convenient modification of the latter is presented together with some illustrative examples.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260307
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  • 61
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    Electronic Resource
    A unitary group formulation of many-body theory: Diagram systematics and use of the spin shifts (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 125-143 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper shows that the spin-shift formalism developed in B. T. Pickup and A. Mukhopadhyay [Int. J. Quantum Chem. 26, 101 (1984)] supports a one-component diagrammatics which has a systematics akin to that in the spin-orbital many-body theory. The diagrams are neither Goldstone nor Yutsis type, and characterize the chain U(2R) ⊃ U(R)⊗SU(2) on which the spin-shift formalism is based. Accordingly, while the lines in such diagrams are labeled by the orbital indices, the diagram structure adequately reflects the irreducible representation of the group U(R). In this sense the paper presents a unitary group approach to the natural generalization of the usual many-body theory for the spin-adapted cases. A set of very simple rules is derived; their similarity with the corresponding rules in the ordinary many-body theory and practical utility are discussed in connection with (a) matrix elements over many-electron spin states and (b) closed- and open-shell many-body perturbation theory. A possibility of integral-driven many-body perturbation theory for open-shells is indicated. Connections of this formalism with others are also discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260109
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  • 62
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    Electronic Resource
    Electronic structure of the peptide linkage. I. Equilibrium geometry and electronic properties of formhydroxamic acid (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 183-196 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The equilibrium geometry of formhydroxamic acid has been calculated within the framework of the INDO-MO formalism. Various structural factors are analyzed and discussed in terms of the calculated force constants and charge distribution. The possibility of internal rotation around the C—N bond of formhydroxamic acid has been examined. The potential energy surface for the amide-imide tautomerism is explored by calculating the geometries and characterizing saddle points on that surface. The cyclic and open dimers of formhydroxamic acid are examined and the hydrogenbond energy and length are calculated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260204
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  • 63
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    Usage de l'algkbre de lie su(n) dans l'etude des systèmes quantiques à n etats. III. Définition et obtention des constantes du mouvement conjoncturelles (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 479-488 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: From the density operator, some constants of the motion are defined and established. We suggest calling them conjunctural constants of the motion. It is proved that no more than n - 1 of them can be linearly independent. Using su(m) (m 〈 n ) subalgebra associated with the Hamiltonian-operator, it is shown how conjunctural constants of the motion can be expressed in terms of the coherence vector components.
    Notes: A partir de I'opérateur-densité d'un système quantique à n états, sont définies et calcultes des constantes du mouvement pour lesquelles est proposée I'appellation nouvelle de conjoncturelles. On établit qu'il en existe au maximum n - 1 linéairement indépendantes. A I'aide des sous-algèbres su(m) (m 〈 n ), on montre comment il est possible d'introduire, suivant la forme de I'hamiltonien, des constantes du mouvement conjoncturelles reliées aux composantes du vecteur de cohérence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260406
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    Masthead (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260501
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    Theoretical approach of the chemical reactivity: The SN2 reaction (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 593-605 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this survey paper the different possible theoretical ways of treating the SN2 reaction are explained. It is shown that, in the future, experience and theory will very likely complement each other.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260504
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    The concept of the chemical bond (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 709-715 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concept of the chemical bond is very old. Many interpretations have been proposed. Nevertheless, the problem is far from being solved. At the present time, the chemist has the choice between two models: the Lewis model (electron pairs) and the quantum model. In spite of a current opinion, both models are not logically equivalent. The localization of molecular orbitals is only a mathematical operation which does not involve any physic localization of the electrons. The loge theory is not more satisfying owing to the fact that loges with minimal fluctuation do not exist in all molecules. The theory of orbital domains seems to bring a solution. Nevertheless, its interpretation can be obtained only outside the strict framework of quantum mechanics.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260510
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    Convergence of LCAO density matrices in Hartree - Fock calculations on extended model chains (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 717-723 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some mathematical implications of the extended nature of model chains are reviewed to call attention to their importance in electronic structure calculations at the restricted Hartree-Fock Roothaan level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260511
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    The effect of an impurity in quasi-one-dimensional systems: Green's function and cluster model approach in comparison (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 753-768 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of an impurity in a quasi-one-dimensional system is addressed. A hydrogen atom in a lithium chain serves as physical model. Two complementary descriptions, the cluster model approach with focus on local interactions, and the self-consistent Green's function approach which takes into account the extended nature of the system will be presented at the Hartree-Fock level. The results of both approaches are discussed in a comparative analysis.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260515
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    Quantum chemical studies on zeolites and silica (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 793-822 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After mentioning differences in C—O and Si—O bonding and different structural types of silicates, the conclusion that interactions between external partners and surfaces of silica and zeolites are mostly dominated by van der Waals forces is discussed. Consequently, the theoretical treatment includes (i) selection of appropriate cluster models, (ii) application of nonempirical quantum chemical methods for obtaining interaction potentials, and (iii) statistical thermodynamic evaluation of adsorption characteristics. As examples vibrational frequencies of H2O and NH3 adsorbed on cationic sites, the interaction of conjugated hydrocarbons with Na+ sites, and the interaction of H2O with various sites on silica and zeolite surfaces are considered.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260519
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    A review of a theoretical model of the excitonic superconductivity in CdS and CuCl (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 831-841 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this review we briefly outline the model developed by Collins and co-workers [T. C. Collins, A. B. Kunz, and R. S. Weidman, Recent Advances in Quantum Theory of Polymers, J. M. Andre et al., Eds., Lecture Notes in Physics (Springer-Verlag, New York, 1979), Vol. 113, p. 240; T. C. Collins, M. Seel, J. J. Ladik, M. Chandrasekhar, and H. R. Chandrasekhar, Phys. Rev. B 27, 140 (1983)] for CdS and CuCl. The model should be applicable to organic semi-conductors. It is the outgrowth of the work of Little [W. A. Little, Phys. Rev. 134, 1416A (1964)], Devreese et al. [J. T. Devreese, A. B. Kunz, and T. C. Collins, Solid State Commun. 11, 673 (1972)] and a large amount of literature concerning He3 p-state [A. J. Leggett, Rev. Mod. Phys. 47, 331 (1975)]. This model is built around calculated band structures and the polarization of the valence band by conduction electrons at moderately high impurity concentrations. We extend the model to include both singlet and triplet paired spin states. The parallel paired states contribute a paramagnetic term to the susceptibility, and we discuss the conditions for this term to dominate over the diamagnetic term.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260521
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    Origin of high efficiency and specificity of biochemical reactions (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 857-872 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is suggested that the extreme efficiency and specificity observed for chemical reactions in biological systems (compared to chemical reactions occurring under common chemical conditions) is mainly due to special features of these reactions. A key position is ascribed to the role of weak intermolecular interactions (also called noncovalent or van der Waals); in addition, the important role of the entropy and of cyclic or cavitylike shapes of numerous reaction sites, together with the influence of strong local electric fields on transport phenomena and reactivity are discussed. The greatest attention is paid to the applicability of computational methods for evaluation of weak intermolecular interactions, ranging from beyond Hartree - Fock methods to empirical potentials.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260523
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    A model of the primary process in photosynthesisA lecture presented at the Colloquium/Advanced Studies Institute on Mechanisms of Elementary Physico-Chemical Processes, Sorrento, Italy, May 2-14, 1983. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 917-931 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The arrangement of membrane-bound pigments, proteins, and lipids in the thylakoids of higher plants is described, and the role of the membrane in preventing the back-reaction is discussed. The photosynthetic bacterium halobacterium halobium is also described. A simplified quantum-mechanical picture of the primary process in photosynthesis is presented, and the mechanism of electron-hole separation in this picture is compared with the corresponding mechanism in a silicon solar cell. An appendix discusses the application of Frenkel exciton theory to the antenna effect.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260527
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    Probable physical mechanisms of the activation of oncogenes through carcinogens (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 955-964 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A brief review is given of the three main known biochemical mechanisms of human oncogene activation. The underlying possible physical and chemical mechanisms (both short- and long-range) caused by chemical carcinogens are also briefly discussed. The probable role in carcinogenesis of conformational solitons generated after the release of carcinogens previously bound to nucleotide bases is pointed out. For such a soliton the Hamiltonian is written down and the solution of classical equations of motion is outlined.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260530
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    Dynamics of enzyme reactions in solution and in heterogeneous media (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 943-953 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzymes are catalysts occurring in living cells. The aim of this paper is to describe some basic properties of enzymes and to understand on a physical basis how the intracellular milieu may control the kinetics of enzyme reactions. We shall therefore consider in succession some kinetic properties of enzymes in solution and the way cell surfaces and biological membranes control the dynamics of enzyme reactions. The choice of topics which have been selected in this paper is somewhat arbitrary and certainly reflects the tastes and the personal interests of the authors.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260529
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    A classification of polyenes into 4L + 2- and 4L-classes on the basis of Coulson's bond orders and information theory and its application to the interpretation of electrocyclic reactions (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 993-1015 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that in the framework of the π-electron approximation even polyenes can be unambiguously divided into 4L- and 4L +2- classes. The classification scheme is based upon the sign alternation of the bond-order between the first and the last atoms and upon the different information content of the bond-order distribution for 4L- and 4L +2- polyenes, respectively. The classification has been shown to hold for the four lowest-lying electronic states: the ground state 1Ag-, the spectroscopically permitted excited state 1Bu+, the spectroscopically forbidden state 1Ag-, and the lowest triplet state 3Bu+ at all levels of sophistication in the π-electron approximation, ranging from the simple Hückel Hamiltonian to the PPP-multi-CI approach. It is shown that the proposed classification is valid also for heteropolyenes and polyenelike/heteropolyenelike fragments from complex organic molecules. The classification has been shown to be useful for the theoretical interpretation of thermo- and photoelectrocyclic reactions. The sign of the bond order between the first and the last atoms (or the average information content) determines unambiguously the topology of the forming cyclic transition state and, thence, the course and the mechanism of these reactions. The results obtained indirectly support the hypothesis that the lowest excited states in butadiene and hexatriene are of the type 1Bu+.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260605
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    Introduction (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. vii 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260702
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    Convergence properties of Hartree-Fock SCF molecular calculations (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 1039-1049 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hartree-Fock equations are viewed as nonlinear algebraic equations that can be solved iteratively. Provided we assume the existence of a solution, valuable properties of convergence may be assessed. The close connection between convergence of the SCF procedure and stability properties of the solution is shown from a nonapproximate standpoint. The convergence features of level-shifting convergence-forcing techniques are analyzed. The connection between this nonlinear algebraic approach and the related gap equation is displayed and the example of the restricted Hartree-Fock hydrogen molecule is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260608
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    Many-electron theory of autoionizing states using complex coordinates: The position and the partial and total widths of the Ne+ 1s hole state (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 1017-1027 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article presents the first results of the application of quantum mechanics with complex coordinates to the calculation of partial widths for the radiationless decay of an inner-hole excited autoionizing state, the Ne+1s2s22p6 2S. This is succeeded by the reduction of the multi-electron, multichannel problem in the complex energy plane to five, symmetry adapted, two-electron problems, in accordance with a published theory of many-electron resonances. These two-electron problems are solved independently by using rotated analytic Hartree-Fock orbitals (expressed in terms of Slater orbitals) for the localized components, and Slater plus Gamow orbitals for the rotated, asymptotic square-integrable functions carrying the width information. A recently proposed variational principle is employed for the optimization of nonlinear parameters. Within this independent asymptotic pair approximation (IAPA), our results for the partial widths to the five Ne2+ channels are (in 10-2 a.u.): 1s-2p2 1D: 0.560, 1S: 0.048; 1s-2s2p, 3P0: 0.029, 1P0: 0.154; 1s-2s2, 1S: 0.044. The total width is 0.835. These numbers agree reasonably well with those obtained by Kelly [Phys. Rev. A 11, 556 (1975)] from a many-body perturbation theory (MBPT) calculation, and by Howat et al. [J. Phys. B 11, 1575 (1978)] from a configuration-interaction in the continuum calculation. The most recent experimental results yield 0.604, 0.089, 0.063, 0.174, and 0.060, respectively, with a total width of 0.99. Previous real-coordinate many-electron calculations by Beck and Nicolaides-including relativistic and radiative effects-have predicted the position of the Ne+ 1s hole state at E0 = 870.4 eV above the Ne ground state. It has already been shown that the real energy corresponding to the localized component of the autoionizing state is stable under rotations of the function space describing it. Therefore, the earlier E0 can be incorporated into the present calculation in the complex plane. The shift due to the additive contribution of the IAPA is found to be - 0.09 eV. When this is added to E0, the final E = 870.3 eV is in excellent agreement with experiment [870.3 eV; T. D. Thomas and R. W. Shaw, Jr., J. Electron. Spectrosc. Relat. Phenom. 8, 45 (1976)].
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560260606
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    The living state. XIII. Does matter become “mind”? (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 45-53 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Consciousness is defined as a “response potential” and is stated to be present in all modalities of physical universe. Given this, upon the gathering of interacting complex systems, new functional ensembles bearing “mind”-like or “mindal” properties arise. These properties are delineated. They would arise in a coupled system by producing an “order” or “action” parameter, allowing for adiabatic elimination of variables and enslavement of subsystems by it. Singularities, space-time asymmetry, and action would irrevocably ensue. An experimentally testable model of “mind” is thus projected.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260706
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    A model for the origin of biological information (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 73-86 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260710
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    Reproducibility of amino acid compositions in repeated copolymerizations of amino acids (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 103-108 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino acid analysis has been performed on the products of four simultaneous separate thermal copolymerizations of a set of 18 amino acids. Four analyses have been performed also on aliquots of one of the products. Standard deviations have been calculated for the analyses of the products of the four separate copolymerizations, and for the four aliquots of one copolymerization. All calculations indicate a high reproducibility in the copolymerization reactions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260713
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    Hyperspherical coordinate representation of potential surfaces of large molecules (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 267-272 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a previous study an energy criterion has been applied for the simplification of the enumeration problem of various conformers of biomolecules. In the present note, the above energy criterion is combined with a spatial criterion that in general leads to a reduction in the size of those domains of biomolecule potential surfaces within which the search for chemically important conformers is warranted. The above model and the conformational domains of primary interest can be formulated in a hyperspherical representation. Advantages and disadvantages of representing biomolecule potential surfaces in terms of hyperspherical coordinates are discussed.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260728
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    Quenching of anionic free radicals by normal and transformed cells: A probe of phenotypic changes (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 309-314 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ability of three cultured cell lines (NRK, 6M2, and 54-5A4) derived from rat kidney to quench a population of ascorbyl and 2,6-dimethoxy-p-semiquinone free radicals has been investigated by electron spin resonance spectroscopy. The radical scavenging action of normal rat kidney (NRK) cells was the weakest, that of 6M2 cells (reversibly transformed phenotype) was four times stronger than NRK, and that of 54-5A4 cells (irreversibly transformed mutants of 6M2) was 10 times greater than NRK. Free radical quenching experiments were also performed on Chinese hamster ovary (CHO) cells. A much slower scavenging rate was observed for CHO cells of normal phenotype grown in the presence of dibutyryl cyclic AMP than was found for cells of transformed phenotype grown in its absence. The free radical quenching kinetics of the various cell lines studied directly paralleled their state of transformation.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560260732
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    Introduction (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. iii 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260802
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    First principles charge transfer exciton theory of the UV spectrum of DNA (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 223-235 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Slater-Koster resolvent formalism of exciton theory, as proposed originally by Takeuti, has been applied to calculate charge transfer exciton states and to investigate hypochromism in polynucleotides. As a first step, spatially well localized ab initio Wannier functions (WFS) are calculated at the Hartree-Fock level using a two-phase (inter- and intramolecular) localization procedure for the Fourier transformation of the Bloch functions. The single particle energies, entering the Green's function of the polymer, are corrected for electron correlation effects with the help of second order Møller-Plesset (MP) perturbation theory. The interelectronic matrix elements, used in the MP calculation as well as in solving the resolvent problem for the excitons, are calculated in terms of the WFS. Singlet- and triplet-excitonic dispersions, oscillator strengths, the possible affects of ions, hydration, and aperiodicity on the exciton spectrum are discussed.
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    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260724
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    Effect of nucleic acid flexibility upon ASIF (accessible surface integrated field). Possible significance for biochemical reactivity exemplified by aflatoxin B1 binding (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 273-286 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The extent of reactivity of a guanine in B-DNA toward aflatoxin B1 depends on the base sequence surrounding that purine in the double helix. In order to account for this variability, we have computed the ASIF (accessible surface integrated field) index for the N7 atom (at which the reaction occurs) of guanine in a G—C pair surrounded on both sides by different types of base pairs in a model oligohelix. When the conformation of the helix is maintained in the B-DNA form, the correlation ASIF reactivity is limited. A study is performed showing the influence on the ASIF index of different departures from the regular B-DNA conformation, likely to occur in a double helix. It is shown that the correlation ASIF reactivity can be strongly improved by allowing some local departures from this regular arrangement.
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    URL: http://dx.doi.org/10.1002/qua.560260729
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    The Leu5 gramicidin a analog: Molecular mechanics calculations and analysis of single channel steps related to multiplicity of conducting states (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 315-326 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Single-channel studies have shown that there exist a multiplicity of conducting states in Gramicidin A (GA). In an earlier work presented at this symposium, it was proposed that such a multiplicity may be expected from different long-lived side-chain distributions available for the channel molecule. In order to test this hypothesis, Leu5-Gramicidin A was synthesized and the effect of replacing the L · Ala5 residue by L · Leu5 was analyzed. First, molecular mechanics calculations on Leu5-Gramicidin A are presented. Then the single-channel conductance sweeps obtained for Leu5-GA are automatically analyzed in the computer using specifically developed algorithms. The results show a dramatic decrease in the multiplicity of states due to the Leu5 substitution. This experimental result is discussed in the light of structural concepts emerging from molecular mechanics calculations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260733
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  • 88
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    Electronic Resource
    Hamiltonian dynamics of simple chemical reactions (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 347-353 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Hamiltonian formulation of chemical kinetics is applied to all closed, single-step, integer-order chemical reactions. In all cases, the dynamics of the Hamiltonian leads to the correct phenomenological rate equation. The relationship between reaction order and the form of the reaction potential is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260735
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  • 89
    Electronic Resource
    Electronic Resource
    Nonenzymatic hydrolysis of RNA: Pb(II)-catalyzed site specific hydrolysis of transfer RNA. The role of the tertiary folding of the polynucleotide chainThe catalytic property of RNA offers a way around the perennial, chicken and egg problem of early evolution. (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 355-366 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pb2+ specifically cleaves yeast tRNAPhe in orthorhombic crystals at phosphates P18 and P60 in the dihydrouridine (D) and pseudouridine (T) loops, respectively. Although there are three major lead binding sites in the tRNA, it appears that both cleavages are affected by the same lead ion. The P18 site is apparently the same site that is hydrolyzed by Pb2+ in solutions of the tRNA and is the major cleavage site in crystals. It is shown from P32 labeling studies with polynucleotide kinase that the products of Pb2+ cleavage have the 5′-hydroxyls on G18 and C60, and consequently the 3′ phosphates are on D17 and U59. The OH- in the first coordination sphere of the hydroxo complex Pb(OH)+ either directly or through a water molecule abstracts the proton of the 2′-OH of D17. This promotes a nucleophilic attack by 2′-O- on P18 with subsequent cleavage of the P—O5′ ester bond to generate the major Pb2+ cleavage product pG18-A76. The anchoring of the Pb2+ by the T-loop and D-loop residues seemingly provide the right environment for the generation of the hydroxo complex required for the hydrolysis. Additionally the strain of the phosphodiester conformation at P18 enhances the cleavage at that site. The Pb2+-catalyzed cleavage of tRNA exemplifies a mechanism used not only for the hydrolysis of transfer RNA but one potentially used by other RNA-catalyzed reaction utilizing metal ion cofactors.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260736
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  • 90
    Electronic Resource
    Electronic Resource
    Coupled-cluster method with optimized reference state (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 267-291 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We propose a variant of the coupled-cluster (CC) method in which spin orbitals of the reference Slater determinant are optimized in a self-consistent way. This approach is a reformulation of the Brueckner-Hartree-Fock (BHF) method used in nuclear physics and known also as the exact SCF method. We discuss the use of the reference-state determinants built of HF, natural, and Brueckner spin orbitals, with relations among them investigated in terms of the many-body perturbation theory (MBPT). It is shown that the Brueckner spin orbitals emerge as a convenient basis set in the coupled-cluster method and equations that determine these spin orbitals are found. The Brueckner spin orbitals can be calculated as eigenvectors of a certain Hermitian one-electron operator which has a form of the Hartree-Fock operator plus a “correlation potential” depending linearly on two- and three- electron cluster amplitudes. The usual decoupling scheme in the coupled-cluster method leads to a hierarchy of approximations; in the first nontrivial one the three-electron cluster amplitudes are neglected, and the two-electron ones are determined by solving Čižek's CPMET equations. We also analyze the problem of spatial, spin, and time-reversal symmertry in the CC and BHF methods. If (and only if) the reference-state determinant belongs to a one-dimensional representation of a certain symmetry subgroup of the system, the CC operator and the BHF one-electron operator are invariant with respect to this subgroup. Thus the restricted (entirely symmetry-adapted) version of the BHF method can be formulated only for the closed-shell systems. This is done for the above-mentioned approximate BHF method. We discuss also the usefulness of the BHF method in application to extended metallic systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260827
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  • 91
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    Electronic Resource
    Introductory remarks (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 21-24 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260805
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  • 92
    Electronic Resource
    Electronic Resource
    Formulas for three-center exchange integrals by computer implementation of the Löwdin α-function method (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 61-66 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By use of computer algebra and expansions of orbitals about a single center in spherical harmonics with a matrix representation for the α-function coefficients it is possible to produce formulas for each term of an infinite series that represents the value of a three-center exchange integral. Only seven terms are required to get six decimal digits for triatomic hydrogen. This method is readily generalized to solve all three-center exchange integrals over Slater-type orbitals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260810
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  • 93
    Electronic Resource
    Electronic Resource
    The simulated ab initio molecular orbital (SAMO) method. VIII. A study of linear polyfluoroethylenes and polychloroethylenes (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 407-432 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The simulated ab initio molecular orbital (SAMO) method band structures of six fluorinated and six chlorinated polymers derived from linear polyethylene are presented and compared with extended Huckel and CNDO/2 studies and with the results of ESCA spectroscopy.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260838
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  • 94
    Electronic Resource
    Electronic Resource
    Perturbation theory studies of the hydrogen Zeeman effect - preliminary results (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 449-455 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The summation of the perturbation series for the hydrogen Zeeman effect using the renormalized series technique is studid. Improved results are obtained compared to those obtained from the unrenormalized series; the method has the advantage of not requiring any information on the largeorder behavior of the perturbation series coefficients.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260841
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  • 95
    Electronic Resource
    Electronic Resource
    Fine and hyperfine structure of the two lowest bound states of Be- and their first two ionization thresholds (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 467-481 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The two lowest bound excited states of the Be- ion, 1s2 2s2p2 4P and 1s2 2p3 4S0, and their respective thresholds, Be 1s2 2s2p 3P0 and Be 1s2 2p2 3P, and the thresholds of these, Be+ 1s2 2s and Be+ 1s2 2p, have been examined using many-body methods. Here, we present the electron affinities (EAs) or ionization potentials, fine and hyperfine structure, and the electric dipole transition probabilities associated with these states and compare them with existing theory and experiment when available. Based on our new EA, a suggestion is made as to why no negative ion transition has yet been seen in the laboratory.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260843
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  • 96
    Electronic Resource
    Electronic Resource
    Frequency dependence of dc electric-field-induced second-harmonic generation (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 525-536 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We derive theoretical experessions for molecular third-order frequency-dependent susceptibilities which represent dc electric-field-induced second-harmonic generation. Our results are valid also if some of the molecular eigenvalues are degenerate as long as the molecular ground state is nondegenerate. The results are in suitable form for quantitative applications, either to small atoms or molecules or to large organic conjugated or aromatic molecules.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260848
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  • 97
    Electronic Resource
    Electronic Resource
    Parallelism in quantum chemistry: Hydrogen bond study in DNA base pairs as an example (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 601-618 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We present results on the energetics of the hydrogen bridges for the Guanine-Cytosine pair obtained in a DNA fragment consisting of three stacked base pairs in the B-DNA conformation. The wave function computations on the 87 atom system are all-electron ab initio SCF-MO computations obtained with a basis set of 1032 primitive gaussian functions contracted to 315. Even if the results are only preliminary, one can tentatively advance conclusions relative to the molecular field effect of stacked base-pairs on the potential energy surface for a hydrogen bond. These computations have been performed with a modified version of our molecular program, which uses an IBM 4341 host and six to ten attached array processors (FPS-164) in parallel. The strategy to convert the program from sequential to parallel is briefly outlined and comparisons with our parallel system are made with a present-day “vector” super-computer. From these studies, we conclude that if one adopts the “parallel” approach presented and tested here, much larger chemical systems than previously are now amenable to all-electron ab initio computations.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260854
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  • 98
    Electronic Resource
    Electronic Resource
    Network relations on potential surfaces as aids to computer-based quantum-chemical synthesis planning (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 675-681 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Current computer hardware developments, in particular, vector processing and parallel processing, are likely to open the door for new applications in quantum chemistry. One applied field that is expected to evolve is a computer-based approach to quantum-chemical synthesis design. Whereas some of the computational difficulties still appear formidable, there are reasons to be optimistic: besides the direct impact of computer hardware developments on existing methods, new theoretical approaches such as density functional theory and numerical molecular wave functions may also become feasible. The topological model of energy hypersurfaces, reaction topology, and quantumchemical manifold theory of reacting systems form a possible framework for a global analysis of a set of all reactions involving a fixed set of nuclei and a fixed number of electrons. The apparent bottleneck for the application of the topological method is the actual computation of the catchment regions (open sets) of reaction topology Tc. In this study some properties of catchment region boundaries are described which lead to computational simplifications. Whereas the ultimate goal of the proposed analysis is to serve as an aid in future quantum-chemical synthesis planning, nonetheless, the boundary networks and sum rules developed in this study may also be of some immediate interest in local surface analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260859
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  • 99
    Electronic Resource
    Electronic Resource
    Quantum Monte Carlo study of the classical barrier height for the H + H2 exchange reaction: Restricted versus unrestricted trial functions (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 709-717 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fixed-node quantum Monte Carlo (QMC) method is used to obtain the classical barrier height for the H + H2 exchange reaction. Using a spin-restricted, single-determinant trial function ΨT, the authors find that the reaction barrier Eb is less than 9.69 ± 0.25 kcal/mol. This mean value is below the calculated energy barrier obtained by Liu in the most extensive CI calculations on this system. Furthermore, the QMC saddle-point energy of - 1.65903 ± 0.00040 hartrees at the CI-determined geometry lies 0.00027 a.u. (0.17 kcal/mol) below Liu's best CI value. Finally, spinrestricted and spin-unrestricted single-determinant trial functions are contrasted. Although the variational energy 〈ΨT|H|ΨT〉 for an SCF ΨT must be lower for the unrestricted case, this is not true generally for QMC. In fact, we show that if the unrestricted SCF ΨT has the lower QMC energy, then there exists another spin-restricted, single-determinant ΨT whose QMC energy is lower than the QMC energy of the spin-restricted SCF ΨT.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260863
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  • 100
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 25 (1984) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560250101
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