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  • 2000-2004  (9)
  • 1995-1999  (783)
  • 1955-1959  (4)
  • 1890-1899
  • Industrial Chemistry and Chemical Engineering
  • genetic engineering
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 13 (2000), S. 29-42 
    ISSN: 1573-322X
    Keywords: dignity of creatures ; genetic engineering ; human dignity ; inherent value ; Swiss Constitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract In their report for the Swiss government onthe notion of the dignity of creatures, PhilippBalzer, Klaus-Peter Rippe, and Peter Schaber analyzethe relationship between human dignity and the dignityof creatures, taking them as two categoricallydifferent concepts. Human dignity is defined as the``moral right not to be humiliated,'' whereas thedignity of creatures is taken to be ``the inherentvalue of non‐human living beings.'' To my mind there isno need to draw a categorical distinction between thetwo concepts. Both notions could be brought togetherunder an all-encompassing concept of the inherentvalue of living beings, humans and non-humans alike,a concept one could name ``the dignity of livingbeings.'' Indeed, this very notion underlies theposition taken in the report, although this is notmade explicit by the authors themselves. As the aim of the paper is only to clarify theconcepts used, I do not go beyond this ``internal''critique of their position, i.e., I don't assess howthe claims articulated via these concepts – theclaim that humans and/or creatures have an inherentvalue consisting in a supposed intrinsic good – areto be justified, although I myself would be ratherskeptical that this might be successfully done.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 13 (2000), S. 7-27 
    ISSN: 1573-322X
    Keywords: dignity ; Swiss Constitution ; nonhuman inherent value ; genetic engineering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract The 1992 incorporation of an article by referendum in the SwissConstitution mandating that the federal government issue regulations onthe use of genetic material that take into account the dignity ofnonhuman organism raises philosophical questions about how we shouldunderstand what is meant by ``the dignity of nonhuman animals,'' andabout what sort of moral demands arise from recognizing this dignitywith respect to their genetic engineering. The first step in determiningwhat is meant is to clarify the difference between dignity when appliedto humans and when applied to nonhumans. Several conceptions of humandignity should be rejected in favor of a fourth conception: the rightnot to be degraded. This right implies that those who have it have thecognitive capacities that are prerequisite for self-respect. In the caseof nonhuman organisms that lack this capacity, respecting their dignityrequires the recognition that their inherent value, which is tied totheir abilities to pursue their own good, be respected. This value isnot absolute, as it is in the case of humans, so it does not prohibitbreeding manipulations that make organisms more useful to humans. But itdoes restrict morally how sentient animals can be used. In regard togenetic engineering, this conception requires that animals be allowedthe uninhibited development of species specific functions, a positionshared by Holland and Attfield, as opposed to the Original Purposeconception proposed by Fox and the Integrity of the Genetic Make-upposition proposed by Rolston. The inherent value conception of dignity,as here defended, is what is meant in the Swiss Constitution article.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 12 (2000), S. 279-303 
    ISSN: 1573-322X
    Keywords: environment ; genetic engineering ; biotechnology ; pesticides ; agriculture ; pest control ; risks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract Despite the application of 2.5 million tons ofpesticides worldwide, more than 40% of all potentialfood production is lost to insect, weed, and plantpathogen pests prior to harvest. After harvest, anadditional 20% of food is lost to another group ofpests. The use of pesticides for pest control resultsin an estimated 26 million human poisonings, with220,000 fatalities, annually worldwide. In the UnitedStates, the environmental and public health costs forthe recommended use of pesticides total approximately$9 billion/yr. Thus, there is a need for alternativenon-chemical pest controls, and genetic engineering(biotechnology) might help with this need. Diseaseand insect pest resistance to various pests has beenslowly bred into crops for the past 12,000 years;current techniques in biotechnology now offeropportunities to further and more rapidly improve thenon-chemical control of disease and insect pests ofcrops. However, relying on a single factor, like theBacillus thuringiensis toxin that has beeninserted into corn and a few other crops for insectcontrol, leads to various environmental problems,including insect resistance and, in some cases, athreat to beneficial biological control insects andendangered insect species. A major environmental andeconomic cost associated with genetic engineeringapplications in agriculture relates to the use ofherbicide resistant crops (HRC). In general, HRCtechnology results in increased herbicide use but noincrease in crop yields. The heavy use of herbicidesin HRC technology pollutes the environment and canlead to weed control costs for farmers that may be2-fold greater than standard weed control costs. Therefore, pest control with both pesticides andbiotechnology can be improved for effective, safe,economical pest control.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 13 (2000), S. 313-327 
    ISSN: 1573-322X
    Keywords: Agri-biotech companies ; agriculture ; biotechnology ; existing technologies ; farmers ; farm crisis ; genetic engineering ; hunger ; poverty ; productivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract The use of genetic engineering inagriculture has been the source of much debate. Todate, arguments have focused most strongly on thepotential human health risks, the flow of geneticmaterial to related species, and ecologicalconsequences. Little attention appears to have beengiven to a more fundamental concern, namely, who willbe the beneficiaries of this technology? Given the prevalence of chronic hunger and thestark economics of farming, it is arguable thatfarmers and the hungry should be the mainbeneficiaries of agricultural research. However, theapplication of genetic engineering appears unlikely tobenefit either of these two groups. This technology islargely controlled by the private sector, and itscontinued development hinges on its profitability.Thus, the only likely beneficiaries of the applicationof genetic engineering in agriculture are companieswith the capacity to use it.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 13 (2000), S. 43-51 
    ISSN: 1573-322X
    Keywords: genetic engineering ; inherent value ; moral obligation ; Swiss constitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract The Swiss expert report suggests thatthe inherent dignity of a living being be identifiedwith its inherent value. But the phrase ``inherentvalue of a living being'' seems to connote two conceptsof inherent value. One has a morally obligatingcharacter but is counterintuitive because of itsegalitarianism. The other is one of non-moral value.It is more compatible with considered intuitions butinsufficient for substantiating the expert report'sclaim that human beings have moral duties towardsanimals and plants. The paper discusses theseconcepts. Consideration is then given to the problemof how discursive support can be generated for theexpert report's claim that human beings have the moralduty to abstain from impairing those functions andabilities of a non‐uman being that members of itsspecies as a rule can practice.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 12 (2000), S. 319-330 
    ISSN: 1573-322X
    Keywords: biotechnology ; consumer sovereignty ; genetic engineering ; informed consent ; product labeling ; risk communication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract Recently, both consumers and producers ofbiotechnology products have insisted thatcommunication between the two be improved. The formerdemand more democratic participation in the riskassessment process of biotechnology products. Thelatter seek to correct misinformation regardingalleged risks from these products. One way to resolvethese concerns, I argue, is through the use ofbiotechnology labels. Such labeling fosters consumerautonomy and moves toward more participatory decisionmaking, in addition to ensuring that informed consentfrom consumers is maintained. Furthermore, althoughvoluntary biotech-free labeling in lieu of biotechlabels may uphold consumer sovereignty, the latterremains a more effective strategy for achievingethical communication between consumers and producersof biotechnology products.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    International journal of technology and design education 10 (2000), S. 239-254 
    ISSN: 1573-1804
    Keywords: contexts ; critical reflection ; environment ; ethics ; genetic engineering ; impacts ; values
    Source: Springer Online Journal Archives 1860-2000
    Topics: Art History , Education , Technology
    Notes: Abstract Design and technology education aims to prepare young people for living in a rapidly changing technological society which will involve them in making many value judgements, some with complex ethical dimensions. Key aspects of the ethical judgements in relation to genetic engineering are examined: the hidden assumptions, the inevitable unpredictability when dealing with living processes highly interactive with the surroundings, the commercial and political pressures, and the underlying `world-views' and values. It is argued that responsible judgements therefore require wide consultation, sensitivity to social, cultural and moral issues, acknowledgement of the political and economic context, and above all, critical reflection on the beliefs and commitments that are shaping the vision and the drive. Teaching and learning strategies are needed that highlight the social and environmental context of technological activity, that encourage pupils to consider what determines the quality of their own lives and those of others, and that stimulates reflection on the values and beliefs which influence the priorities when value judgements are being made.
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  • 8
    ISSN: 1573-6776
    Keywords: Escherichia coli ; genetic engineering ; metal-binding ; OmpC ; protein engineering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The outer membrane protein, OmpC, from Escherichia coli was used to display metal-binding poly-histidine peptides on the surface of this bacterium. SDS-PAGE analysis of outer membrane protein preparations confirmed the expression of the metal-binding epitopes inserted in position 162 of the mature OmpC protein. Display of these epitopes was confirmed by epifluorescence microscopy of cells bound to Ni2+-NTA-agarose beads and metal adsorption experiments. The cells harboring one or two copies of the metal binding epitope were able to adsorb 3 to 6 times more Zn2+ (13.8 μmol g−1 cell), Fe3+ (35.3 μmol g−1 cell), and Ni2+ (9.9 μmol g−1 cell) metallic ions than control cells expressing the wild-type OmpC.
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  • 9
    ISSN: 1573-6776
    Keywords: bioremediation ; genetic engineering ; heavy metal ; hydrogen sulfide ; thiosulfate reductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The thiosulfate reductase gene (phsABC) from Salmonella typhimuriumwas expressed in Escherichia coliin order to produce sulfide from inorganic thiosulfate and precipitate metals as metal sulfide complexes. The sulfide-engineered strain removed significant amounts of heavy metals from the medium within 24 h: 99% of zinc up to 500 μM, 99% of lead up to 200 μM, 99% of 100 μM and 91% of 200 μM cadmium. In a mixture of 100 μM each of cadmium, lead, and zinc, the strain removed 99% of the total metals from solution within 10 h. Cadmium was removed first, lead second, and zinc last. These results have important implications for removal of metals from wastewater contaminated with several metals.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The journal of ethics 3 (1999), S. 51-71 
    ISSN: 1572-8609
    Keywords: biotechnology ; cloning ; ethics of biotechnology ; ethics of cloning ; ethics of human cloning ; ethics for reproductive technology ; genetic engineering ; human cloning ; religious ethics ; reproductive technology ; secular ethics ; social ethics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy
    Notes: Abstract The advent of cloning animals has created a maelstrom of social concern about the “ethical issues” associated with the possibility of cloning humans. When the “ethical concerns” are clearly examined, however, many of them turn out to be less matters of rational ethics than knee-jerk emotion, religious bias, or fear of that which is not understood. Three categories of real and spurious ethical concerns are presented and discussed: 1) that cloning is intrinsically wrong, 2) that cloning must lead to bad consequences, and 3) that cloning harms the organism generated. The need for a rational ethical framework for discussing biotechnological advances is presented and defended.
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  • 11
    ISSN: 1573-5028
    Keywords: genetic engineering ; 4-hydroxybenzoic acid glucoside ; Lithospermum erythrorhizon ; menisdaurin ; shikonin ; ubiC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biosynthetic pathway to 4-hydroxybenzoate (4HB), a precursor of the naphthoquinone pigment shikonin, was modified in Lithospermum erythrorhizon hairy root cultures by introduction of the bacterial gene ubiC. This gene of Escherichia coli encodes chorismate pyruvate-lyase (CPL), an enzyme that converts chorismate into 4HB and is not normally present in plants. The ubiC gene was fused to the sequence for a chloroplast transit peptide and placed under control of a constitutive plant promoter. This construct was introduced into L. erythrorhizon by Agrobacterium rhizogenes-mediated transformation. The resulting hairy root cultures showed high CPL activity. 4HB produced by the CPL reaction was utilized for shikonin biosynthesis, as shown by in vivo inhibition of the native pathway to 4HB with 2-aminoindan-2-phosphonic acid (AIP), an inhibitor of phenylalanine ammonia-lyase. A feeding experiment with [1,7-13C2]shikimate showed that in the absence of AIP the artificially introduced CPL reaction contributed ca. 20% of the overall 4HB biosynthesis in the transgenic cultures. ubiC transformation did not lead to a statistically significant increase of shikonin formation, but to a 5-fold increase of the accumulation of menisdaurin, a nitrile glucoside which is presumably related to aromatic amino acid metabolism.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 60 (1999), S. 29-42 
    ISSN: 1573-5079
    Keywords: enzyme catalysis ; evolution ; genetic engineering ; photosynthesis ; protein assembly ; protein degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) has played a central role in our understanding of chloroplast biogenesis and photosynthesis. In particular, its catalysis of the rate-limiting step of CO2 fixation, and the mutual competition of CO2 and O2 at the active site, makes Rubisco a prime focus for genetically engineering an increase in photosynthetic productivity. Although it remains difficult to manipulate the chloroplast-encoded large subunit and nuclear-encoded small subunit of crop plants, much has been learned about the structure/function relationships of Rubisco by expressing prokaryotic genes in Escherichia coli or by exploiting classical genetics and chloroplast transformation of the green alga Chlamydomonas reinhardtii. However, the complexity of chloroplast Rubisco in land plants cannot be completely addressed with the existing model organisms. Two subunits encoded in different genetic compartments have coevolved in the formation of the Rubisco holoenzyme, but the function of the small subunit remains largely unknown. The subunits are posttranslationally modified, assembled via a complex process, and degraded in regulated ways. There is also a second chloroplast protein, Rubisco activase, that is responsible for removing inhibitory molecules from the large-subunit active site. Many of these complex interactions and processes display species specificity. This means that attempts to engineer or discover a better Rubisco may be futile if one cannot transfer the better enzyme to a compatible host. We must frame the questions that address this problem of chloroplast-Rubisco complexity. We must work harder to find the answers.
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  • 13
    ISSN: 1572-9788
    Keywords: transgenic carnation ; genetic engineering ; microprojectile bombardment ; stable transformation ; kanamycin selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Highly efficient Agrobacterium-mediated transformation of carnation (Dianthus caryophyllus L.) was obtained by first wounding stem explants via microprojectile bombardment. When this was followed by cocultivation with disarmed Agrobacterium in the dark, the transformation frequency-based on transient GUS expression-increased to over 10-fold that of explants wounded by other means and cocultivated under constant light. Two cycles of regeneration/selection on kanamycin were employed to generate stably transformed carnation plants and eliminate chimeras: first, plantlets were regenerated from inoculated stem explants and then leaves from these plantlets were used to generate transgenes in a second selection cycle of adventitious shoot regeneration. Agrobacterium strain AGLO, carrying the binary vector pCGN7001 containing uidA and nptII genes, was used in the stable transformation experiments. The combination of wounding via bombardment, cocultivation in the dark and two cycles of kanamycin selection yielded an overall transformation efficiency of 1–2 transgenes per 10 stem explants for the three carnation varieties analyzed. Histochemical and molecular analyses of marker genes in T0 and T1 generations confirmed the transgenic nature of the selected plants.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 15 (1998), S. 813-815 
    ISSN: 1573-904X
    Keywords: genetic engineering ; polymers ; drug delivery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    World journal of microbiology and biotechnology 14 (1998), S. 321-330 
    ISSN: 1573-0972
    Keywords: Conifer transformation ; forestry ; genetic engineering ; plantation forestry ; tree improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Genetic improvement in plantation forestry relies significantly on conventional breeding techniques which have been used extensively to improve various characteristics in forest trees such as growth and form, volume yield, resistance to pathogens and quality of the end product. This review concentrates on molecular techniques which have been used successfully in agriculture and which have more recently become available to improve further characteristics of forest trees and introduce new traits which are currently not available in the breeding population.
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  • 16
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 30 (1998), S. 155-167 
    ISSN: 0887-3585
    Keywords: X-ray diffraction ; protein folding ; genetic engineering ; circular permutation ; 1,3-1,4-β-glucanase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The 1,3-1,4-β-glucanases from Bacillus macerans and Bacillus licheniformis, as well as related hybrid enzymes, are stable proteins comprised of one compact jellyroll domain. Their structures are studied in an effort to reveal the degree of redundancy to which the three-dimensional structure of protein domains is encoded by the amino acid sequence. For the hybrid 1,3-1,4-β-glucanase H(A16-M), it could be shown recently that a circular permutation of the sequence giving rise to the variant cpA16M-59 is compatible with wildtype-like enzymatic activity and tertiary structure (Hahn et al., Proc. Natl. Acad. Sci. USA 91:10417-10421, 1994). Since the circular permutation yielding cpA16M-59 mimicks that found in the homologous enzyme from Fibrobacter succinogenes, the question arose whether de novo circular permutations, not guided by molecular evolution of the 1,3-1,4-β-glucanases, could also produce proteins with native-like fold. The circularly permuted variants cpA16M-84, cpA16M-127, and cpA16M-154 were generated by PCR mutagenesis of the gene encoding H(A16-M), synthesized in Escherichia coli and shown to be active in β-glucan hydrolysis. CpA16M-84 and cpA16M-127 were crystallized in space groups P21 and P1, respectively, and their crystal structures were determined at 1.80 and 2.07 Å resolution. In both proteins the main parts of the β-sheet structure remain unaffected by the circular permutation as is evident from a root-mean-square deviation of main chain atoms from the reference structure within the experimental error. The only major structural perturbation occurs near the novel chain termini in a surface loop of cpA16M-84, which becomes destabilized and rearranged. The results of this study are interpreted to show that: (1) several circular permutations in the compact jellyroll domain of the 1,3-1,4-β-glucanases are tolerated without radical change of enzymatic activity or tertiary structure, (2) the three-dimensional structures of simple domains are encoded by the amino acid sequence with sufficient redundancy to tolerate a change in the sequential order of secondary structure elements along the sequence, and (3) the native N-terminal region is not needed to guide the folding polypeptide chain toward its native conformation. Proteins 30:155-167, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 17
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 536-539 
    ISSN: 0894-3230
    Keywords: enzyme design ; enzyme mechanism ; genetic engineering ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Aspartate aminotransferase (AATase) and aminocyclopropane carboxylate synthase (ACC synthase) are pyridoxal phosphate (PLP)-dependent enzymes whose common junction of mechanistic divergence is after the formation of a Cα carbanion from the amino acid substrate bound to PLP as a Schiff base (aldimine). AATase catalyzes the reversible interconversion of α-amino acids and α-keto acids, while ACC synthase effects the irreversible decomposition of S-adenosylmethionine (SAM) to 1-aminocyclopropane-1-carboxylate (ACC) and 5′-methylthioadenosine (MTA). ACC is subsequently converted to ethylene, the plant ripening and senescence hormone, by ACC oxidase, the next enzyme in the pathway. AATase and ACC synthase exhibit many similar phenomenological characteristics that result from different detailed mechanistic origins. The kcat/KM versus pH profiles for both enzymes are similar (AATase, acidic pKa = 6.9, basic pKa = 9.6; ACC synthase, acidic pKa = 7.5, basic pKa = 8.9); however the acidic pKa of AATase reflects the ionization of an enzyme proton from the internal Schiff base, and the basic one is that of the α-amino group of the substrate, while the opposite situation obtains for ACC synthase, i.e. the apparent pKa of 7.4 is due to the α-amino group of SAM, whereas that of 9 reflects the Schiff base pKa. The mechanistic imperative underlying this reversal is dictated by the reaction mechanism and the low pKa of the α-amino group of SAM. The low pKa of SAM requires that the enzyme pKa be moved upward in order to have sufficient quantities of the reacting species at neutral pH. It is shown by viscosity variation experiments with wild-type and active site mutant controls of both enzymes that the reaction of SAM with ACC synthase is 100% diffusion controlled (kcat/KM = 1.2 × 106 l mol-1 s-1) while the corresponding reaction for the combination of L-aspartate with AATase is insensitive to viscosity, and is therefore chemically not diffusion limited. Tyr225 (AATase) or Tyr233 (ACC synthase) forms a hydrogen bond with the PLP in both enzymes, but that formed with the former enzyme is stronger and accounts for the lower pKa of the Schiff base. © 1998 John Wiley & Sons, Ltd.
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  • 18
    ISSN: 1573-9368
    Keywords: bioreactor ; gene farming ; genetic engineering ; mammary gland ; milk composition ; recombinant protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One transgenic rabbit line was generated carrying a fusion gene consisting of the cDNA for human IGF-1 fused to a mammary gland specific expression cassette derived from bovine alpha-S1-casein sequences. Transgene expression was shown to be strictly tissue and lactation period specific. The transgenic rabbit line was bred for six generations. All transgenic animals showed stable production of biologically active IGF-1 over the generations and no apparent effect on the physiological or reproductive performance was observed. The absence of adverse effects on homozygous transgenic rabbits suggested the absence of insertional mutagenesis. Eight hemizygous transgenic offspring analysed produced on average 363 ± 12μg/ml (ranging from 223 ± 61 to 484 ± 39 μg/ml) mature human IGF-1 in their milk, whereas three homozygous animals produced on average 543 ± 41 μg/ml (ranging from 360 ± 15 to 678 ± 80 μg/ml). Homozygous huIGF-1 females clearly showed a significantly increased production performance of the recombinant protein.
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  • 19
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    Electronic Resource
    Springer
    Plant molecular biology 38 (1998), S. 1011-1019 
    ISSN: 1573-5028
    Keywords: choline oxidase ; genetic engineering ; glycinebetaine ; low-temperature tolerance ; salt tolerance ; transgenic rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetically engineered rice (Oryza sativa L.) with the ability to synthesize glycinebetaine was established by introducing the codA gene for choline oxidase from the soil bacterium Arthrobacter globiformis. Levels of glycinebetaine were as high as 1 and 5 μmol per gram fresh weight of leaves in two types of transgenic plant in which choline oxidase was targeted to the chloroplasts (ChlCOD plants) and to the cytosol (CytCOD plants), respectively. Although treatment with 0.15 m NaCl inhibited the growth of both wild-type and transgenic plants, the transgenic plants began to grow again at the normal rate after a significantly less time than the wild-type plants after elimination of the salt stress. Inactivation of photosynthesis, used as a measure of cellular damage, indicated that ChlCOD plants were more tolerant than CytCOD plants to photoinhibition under salt stress and low-temperature stress. These results indicated that the subcellular compartmentalization of the biosynthesis of glycinebetaine was a critical element in the efficient enhancement of tolerance to stress in the engineered plants.
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  • 20
    ISSN: 1572-9788
    Keywords: chitinase ; Diplocarpon rosae ; disease resistance ; genetic engineering ; Rosa hybrida L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Blackspot, caused by the Ascomycete fungus Diplocarpon rosae, is the most widespread and pernicious disease of cultivated roses. While some species of rose possess resistance to D. rosae, none of the modern-day rose cultivars are fully resistant to the pathogen. In the current study, Biolistic gene delivery was used to introduce a rice gene, encoding a basic (Class I), chitinase into embryogenic callus of the blackspot-susceptible rose (Rosa hybrida L.) cv. Glad Tidings. The plasmid used for transformation carried the neomycin phosphotransferase (nptII) gene facilitating the selection and regeneration of transgenic plants on medium containing 250 mg/l kanamycin. Southern analysis confirmed integration of 2–6 copies of the chitinase gene into the rose genome; gene expression was confirmed by enzyme assay. Bioassays demonstrated that expression of the chitinase transgene reduced the severity of blackspot development by 13–43%. This degree of resistance to the pathogen correlated with the level of chitinase expression in the transgenic rose plants. The introduction of disease defence genes into rose provides a method of producing blackspot-resistant rose cultivars sought by breeders and growers.
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  • 21
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 58 (1998), S. 162-169 
    ISSN: 0006-3592
    Keywords: bioinformatics ; metabolic engineering ; genetic engineering ; mathematical analysis ; stoichiometry ; enzyme kinetics ; modal analysis ; genetic circuits ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ten microbial genomes have been fully sequenced to date, and the sequencing of many more genomes is expected to be completed before the end of the century. The assignment of function to open reading frames (ORFs) is progressing, and for some genomes over 70% of functional assignments have been made. The majority of the assigned ORFs relate to metabolic functions. Thus, the complete genetic and biochemical functions of a number of microbial cells may be soon available. From a metabolic engineering standpoint, these developments open a new realm of possibilities. Metabolic analysis and engineering strategies can now be built on a sound genomic basis. An important question that now arises; how should these tasks be approached? Flux-balance analysis (FBA) has the potential to play an important role. It is based on the fundamental principle of mass conservation. It requires only the stoichiometric matrix, the metabolic demands, and some strain specific parameters. Importantly, no enzymatic kinetic data is required. In this article, we show how the genomically defined microbial metabolic genotypes can be analyzed by FBA. Fundamental concepts of metabolic genotype, metabolic phenotype, metabolic redundancy and robustness are defined and examples of their use given. We discuss the advantage of this approach, and how FBA is expected to find uses in the near future. FBA is likely to become an important analysis tool for genomically based approaches to metabolic engineering, strain design, and development. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:162-169, 1998.
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  • 22
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 57 (1998), S. 477-483 
    ISSN: 0006-3592
    Keywords: Vitreoscilla hemoglobin ; bacterial hemoglobin ; Serratia marcescens ; genetic engineering ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The bacterial hemoglobin from Vitreoscilla has been shown to increase growth yield and yield of genetically engineered product in Escherichia coli. To test the generality of this phenomenon, the approximately 560-bp bacterial (Vitreoscilla) hemoglobin gene (vgb) (including the native promoter), cloned into the vector pUC8 in two constructs containing about 1650 and 850 bp, respectively, of Vitreoscilla DNA downstream of vgb, was transformed into Serratia marcescens. After several transfers of the transformants on selective media, both plasmids became stable in this host and the resulting strains produced hemoglobin. Both transformants were compared, regarding growth in liquid Luria-Bertani (LB) medium, with untransformed S. marcescens and S. marcescens transformed with pUC8. The vgb-bearing strains had about 5 times lower maximum viable cell numbers than the strains without hemoglobin, but the former also had late log or early stationary phase cells that were 5-10 times larger than those of the latter. Further, on a dry cell mass basis the presence of vgb inhibited cell growth in liquid media. In contrast, growth of the vgb-bearing strains on LB plates based on cell mass (determined from colony size) was markedly enhanced compared with that of the pUC8 transformant. Respiration of the vgb-bearing strains was lower than that of the strains without vgb on a cell mass basis. These results show that the presence of vgb can have idiosyncratic effects and is not always an aid to cell growth so that its use for genetic engineering must be tested on a case by case basis. ©1998 John Wiley & Sons, Inc. Biotechnol Bioeng 57: 477-483, 1998.
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  • 23
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    Biopolymers 45 (1998), S. 269-279 
    ISSN: 0006-3525
    Keywords: spider dragline silk ; genetic engineering ; glycine-rich sequence ; β-sheet structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We described genetically engineered syntheses of tandem repetitive polypeptides consisting of glycine-rich sequence, GlyLeuGlyGlyGlnGlyGlyGlyAlaGlyGlnGlyGlyTyrGly, designated SCAP(1), in spidroin I of spider dragline silk from Nephila clavipes and the secondary conformational analyses in the solid state by Fourier transform ir measurements. The polypeptides composed of 4, 5, 6, 7, 11, 12, or 13 repeats of SCAP(1) were expressed in Escherichia coli, purified by nickel chelate affinity chromatography, and then cleaved with cyanogen bromide to release N- and C-terminal extensions. Typical yields were from 1.2 to 5.2 mg of lyophilized uncleaved polypeptides per liter of fermentation medium at an absorbance of 2.0 at 600 nm, and the production levels increased with decreasing the molecular weight of the expressed polypeptides. The lyophilized powder of cleaved SCAP(13) adopted the random coil, whereas the cast film from formic acid formed the β-sheet structure. The conformational results might indicate that the glycine-rich sequence formed β-sheet structure in spidroin I. Cleaved SCAP(13) started to decompose under nitrogen at ca. 230°C, which was in agreement with the decomposition temperature of the spider dragline silk from N. clavipes. © 1998 John Wiley & Sons, Inc. Biopoly 45: 269-279, 1998
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  • 24
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 25
    ISSN: 0268-2605
    Keywords: Nickel-σ-organyl complexes ; dispersed atomic Ni(0) ; Ni(I) ions ; silica ; EPR ; FMR ; spectrum calculation ; strain ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dispersed atomic nickel(0) is formed during the reaction of the nickel-σ-organyl complexes with silanol groups at temperatures below 373 K. That nickel is oxidized to Ni(I) by protons of the silanol groups in a consecutive step. The Ni(I) portion amounts to about 70% w/w of the Ni used. Six different Ni(I) species are detected by electron paramagnetic resonance. They are stabilized by interaction with the silica surface and the organic moieties; they act as anchor ions for the Ni(0) atoms. Ni(0) crystallites stabilized in this way are about 0.5 nm in diameter after a treatment at 373 K. The influence of the Ni(I) ions on the collective, magnetic properties of the clusters is revealed by calculation of ferromagnetic resonance (FMR) spectra using the independent-grain approach according to Schlömann and Kotyukov. A strain of about 10 GPa is brought about in the nickel crystallites by the interaction with Ni(I) ions. © 1998 John Wiley & Sons, Ltd.
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  • 26
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    Applied Organometallic Chemistry 12 (1998), S. 375-379 
    ISSN: 0268-2605
    Keywords: granular films ; pulsed laser deposition ; giant magnetoresistance ; microstructure ; magnetic properties ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An investigation into the microstructural properties of CoxAg1 - x films, grown by pulsed laser deposition, as a function of deposition and post-deposition annealing temperature is reported. Surface morphology and microstructure were investigated by XPS, SEM and TEM measurements. Magnetic measurements were used to gain further information on particle size distributions through the analysis of the temperature dependence of the irreversible magnetization. Depending on cobalt content, deposition and post-deposition annealing temperature, the maximum of the cobalt grains diameter distribution was estimated to be in the range 2-6 nm. © 1998 John Wiley & Sons, Ltd.
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  • 27
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    Applied Organometallic Chemistry 12 (1998), S. 381-386 
    ISSN: 0268-2605
    Keywords: nanoparticles ; magnetic susceptibility ; magnetic anisotropy ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dynamical behavior of γ-Fe2O3 particles dispersed in a polymer have been investigated by a.c. susceptibility and Mössbauer spectroscopy measurements. The effect of interparticle interactions on the relaxation time is satisfactorily described by a superparamagnetic model where the dipolar energy is determined by a statistical calculation for a disordered arrangement of particles with volume distribution and easy axes in random orientations. The results indicate that the single particle anisotropy energy is mainly determined by surface anisotropy and that the energy barrier increases with the interaction strength. © 1998 John Wiley & Sons, Ltd.
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  • 28
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    Applied Organometallic Chemistry 12 (1998), S. 467-467 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 29
    ISSN: 0268-2605
    Keywords: fungicidal activity ; Ceratocystis ulmi ; triphenyltin(IV) ; tributyltin(IV) ; phenolic bridge ; carboxylate bridge ; polymers ; trigonal bipyramidal structures ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methods of synthesis, elemental analysis, IR and NMR spectroscopic data and fungicidal activity against Ceratocystis ulmi are reported for a series of triorganotin esters of N-arylidene-ω-amino acids of general formula R3SnOCO(CH2)nN = CHAr (R = Ph, n-Bu; Ar = 2-HOC6H4, 2-HOC10H6; n = 1, 2, 3 and 5). The crystal structures for two of the compounds, tributyltin N-2-hydroxynaphthalidene glycinate (1) and tributyltin N-2-hydroxynaphthalidene-β-alaninate (2), have been determined. Although both of these compounds have a trans-R3SnO2 structure, in compound 1 the carboxylate group is monodentate and the fifth coordination position around the tin atom is taken up by a coordinated phenolic group, whereas in 2 the carboxylate group is bridging. These two examples thus correspond to the two different structures reported for trans-R3SnO2 complexes. Both compounds were found to be active against Ceratocystis ulmi, but there was no significant difference in their levels of biological activity against this particular fungus. Apart from compound 1, the other tributyltin compounds reported are believed to adopt the carboxylate bridging mode shown by compound (2).Crystal data: for 1, crystals monoclinic, space group P21/c, a = 12.9435(11) Å, b = 13.5769(10) Å, c = 15.7715(12) Å, β = 108.919(6)°, Z = 4, Rf = 0.046 and Rw = 0.058 for 1448 significant reflections; for 2, crystals monoclinic, space group C 2/c,a = 24.588(14) Å, b = 9.733(3) Å, c = 27.611(12) Å,β = 113.49(4)°, Z = 8, Rf = 0.053 and Rw = 0.069 for 3822 significant reflections. © 1998 John Wiley & Sons, Ltd.
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  • 30
    ISSN: 0268-2605
    Keywords: density functional calculation ; binuclear metal carbonyl ; Cr2(CO)6+ ; laser ablation ; molecular beam ; optimized structures ; dissociation energy ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Density functional calculations have been made on a binuclear metal carbonyl ion Cr2(CO)6+ found in our laser ablation-molecular beam (LAMB) experiment. Optimized structures are calculated for three different conformations: T33 of D3d symmetry with three terminal carbonyl groups on each chromium atom, B2T22 of D2h symmetry with two bridging carbonyl groups and two terminal carbonyl groups on each chromium atom, and B4T11 of D4h symmetry with four bridging carbonyl groups and one terminal carbonyl group on each chromium atom. The most stable conformation is T33 which is 36.76 and 286.44 kJ mol-1 lower in energy than B2T22 and B4T11, respectively. The difference of conformation exerts a significant influence on the internuclear distance between chromium and the carbon of terminal CO, but hardly on the Cr-Cr bond length. For B2T22 and B4T11, longer C-O distances for bridging carbonyls compared with those for terminal ones indicate effective π*-back donation from the chromium atom to the bridging carbonyl groups. Furthermore, the relative abundance of Cr2(CO)n+ (n = 0-6) observed in our previous experimental study can be explained qualitatively by comparison of the excess energy produced in the formation of a Cr+-Cr bond with the CO dissociation energy of Cr2(CO)6+. © 1998 John Wiley & Sons, Ltd.
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  • 31
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    Applied Organometallic Chemistry 12 (1998), S. 467-468 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 32
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    Applied Organometallic Chemistry 12 (1998), S. 468-468 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 33
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 34
    ISSN: 0268-2605
    Keywords: metal clusters ; quantum-size effect ; nanostructures ; size effects ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Meta-cluster compounds can be exploited advantageously to study the evolution, with increasing size of the molecules of the physical properties of metal clusters from molecular to bulk-metal behavior. The metal-cluster molecules are well-defined, stoichiometric, chemical compounds. The molecules consist of a metal core of a variable number of atoms, surrounded by a shell of ligand atoms or molecules. Depending on the compound, the type of metal atom may be varied, whereas the core size can be changed from a few up to several thousands of atoms. Accordingly, these materials provide excellent model systems for monodisperse metal particles, embedded in a dielectric matrix, and can be investigated by the well-known experimental techniques of solid-state physics. © 1998 John Wiley & Sons, Ltd.
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  • 35
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    Applied Organometallic Chemistry 12 (1998), S. 475-478 
    ISSN: 0268-2605
    Keywords: organomercurials ; symmetrization ; column chromatography ; organomercury halides ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The symmetrization reaction of organomercury(II) chlorides (RHgCl) to R2Hg and HgCl2 in toluene solution under identical conditions using a basic alumina column has been studied­in order to compare the effect of the nature of the R groups on the extent of symmetrization. The efficiency of symmetrization depends markedly on the electron-withdrawing nature of­R, varying from 90-94% for R = trichlorovinyl or phenyl to 11% for R = 2,6-dimethylphenyl.© 1998 John Wiley & Sons, Ltd.
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  • 36
    ISSN: 0268-2605
    Keywords: HPLC-ICP-MS ; cetaceans ; pinnipeds ; arsenic ; arsenobetaine ; arsenocholine ; whales ; seals ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Total arsenic concentrations and the concentrations of individual arsenic compounds were determined in liver samples of pinnipeds [nine ringed seals (Phoca hispida), one bearded seal (Erginathus barbatus)] and cetaceans [two pilot whales (Globicephalus melas), one beluga whale (Deliphinapterus leucus)]. Total arsenic concentrations ranged from 0.167 to 2.40 mg As kg-1 wet mass. The arsenic compounds extracted from the liver samples with a methanol/water mixture (9:1, v/v) were identified and quantified by anion- and cation-exchange chromatography. An ICP-MS equipped with a hydraulic high-pressure nebulizer served as the arsenic-specific detector. Arsenobetaine (0.052-1.67 mg As kg-1 wet mass) was the predominant arsenic compound in all the liver samples. Arsenocholine was present in all livers (0.005-0.044 mg As kg-1 wet mass). The tetramethylarsonium cation was detected in all pinnipeds (〈0.009 to 0.043 mg As kg-1) but not in any of the cetaceans. The concentration of dimethylarsinic acid ranged from 〈 0.001 to 0.109 mg As kg-1 wet mass. Most of the concentrations for methylarsonic acid (〈0.001 to 0.025 mg As kg-1 wet mass) were below the detection limit. Arsenous acid and arsenic acid concentrations were below the detection limit of the method (0.001 mg As kg-1). An unknown arsenic compound was present in all liver samples at concentrations from 0.002-0.027 mg As kg-1. © 1998 John Wiley & Sons, Ltd.
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  • 37
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    Applied Organometallic Chemistry 12 (1998), S. 520-520 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 38
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    Applied Organometallic Chemistry 12 (1998), S. 520-520 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 39
    ISSN: 0268-2605
    Keywords: organotin ; N-(2-pyridylmethylene)arylamines ; IR ; NMR ; Mössbauer ; mutagenicity ; sister chromatid exchange ; cell cycle delay ; bone-marrow cells ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diorganotin(IV) dichloride complexes of the type R2SnCl2·L (R = methyl, ethyl, vinyl, t-butyl, n-butyl or phenyl; L = N-(2-pyridylmethylene)arylamine) have been synthesized and characterized on the basis of IR, NMR and 119Sn Mössbauer studies. Investigation of the complexes indicated that N-(2-pyridylmethylene)arylamines form distorted trans-octahedral complexes with R2SnCl2 similar to the well-known R2SnCl2·L. Cytogenetic toxicology testing has been performed for Et2SnCl2·L4 [L4 = N-(2-pyridylmethylene)-4-toluidine] in mouse bone-marrow cells in vivo since such testing is a regulatory requirement before new drugs are released. This tin compound induced delay in cell-cycle kinetics and sister chromatid exchanges (SCEs) significantly. The effect of Et2SnCl2·L4 was greater when endogenous glutathione (GSH) was depleted by buthionine sulphoximine (BSO). It seems that Et2SnCl2·L4 induces SCEs due to formation of adduct by binding on DNA which could interfere in DNA synthesis and cause delay in cell proliferation. Depletion of GSH could reduce the shielding effect of GSH on chromatin and allows more Et2SnCl2·L4 to bind on DNA. © 1998 John Wiley & Sons, Ltd.
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  • 40
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 41
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    Applied Organometallic Chemistry 12 (1998), S. 878-878 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 42
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    Applied Organometallic Chemistry 12 (1998), S. 884-884 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 43
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    Applied Organometallic Chemistry 12 (1998), S. 883-884 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 44
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 45
    ISSN: 0268-2605
    Keywords: methylmercury ; analysis ; HPLC- ICP MS ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel technique has been developed for the determination of trace amounts of methylmercury in various sample matrices. The newly developed HPLC method makes it possible to separate methylmercury and inorganic mercury with ultrasonic nebulization and detection by ICP MS for different mercury isotopic masses. The isotope-specific detection allows the application of the species-specific isotope addition method for the determination of methylmercury with a correction for artifact formation. The well-known water-vapour distillation method was used in combination with an enriched stable inorganic mercury isotope (200Hg2+) for the separation of methylmercury from various matrices. The subsequent determination of CH3 - 200Hg+ generated from 200Hg2+ was used in the correction for artifact formation during sample preparation. In comparison with a previously developed HPLC coupling technique with HPF-HHPN (high-performance flow/­hydraulic high-pressure nebulization), the stability of the detection procedure was improved considerably. The limit of detection (S/N = 3) for methylmercury was calculated to be about 0.015 μg kg-1. © 1998 John Wiley & Sons, Ltd.
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  • 46
    ISSN: 0268-2605
    Keywords: methylmercury ; solid-phase microextraction ; gas chromatography-atomic fluorescence ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical method is described for methylmercury determination in fish and aqueous samples using solid-phase microextraction (SPME) followed by gas chromatography-atomic fluorescence spectrometry (GC-AFS). The procedure involves aqueous-phase derivatization of methylmercury species with sodium tetraethylborate in a sample vial and subsequent extraction with a silica fiber coated with poly-­(dimethylsiloxane). The mercury derivatives are desorbed in the splitless injection port of a gas chromatograph and subsequently analyzed by GC-AFS. The headspace SPME procedure is used and parameters affecting the extraction, adsorption and desorption are evaluated. Results for methylmercury analysis in standard reference material (DORM-2) and fish samples are presented. © 1998 John Wiley & Sons, Ltd.
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  • 47
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    Applied Organometallic Chemistry 12 (1998), S. 571-576 
    ISSN: 0268-2605
    Keywords: zerovalent metals ; bromoalkyltriphenylphosphonium bromides ; methylmercuric acetate ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aqueous solutions of bromoalkyltriphenylphosphonium bromides react with zerovalent metals, causing their dissolution. The reaction initially follows second-order kinetics, with the rate depending on both metal and bromide concentrations. Zerovalent metals similarly react with aqueous methylmercuric acetate and other dissolved organometals. © 1998 John Wiley & Sons, Ltd.
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  • 48
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    Applied Organometallic Chemistry 12 (1998), S. 659-666 
    ISSN: 0268-2605
    Keywords: polymers ; polyphosphazenes ; synthesis ; surfaces ; surface reactions ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The macromolecular substitution approach for the synthesis of polyphosphazenes provides access to many different polymers. However, it precludes the use of reagents that contain two or more functional groups because such compounds would cause extensive crosslinking of the chains. This presents a problem because many of the uses for which polyphosphazenes seem ideally suited require the presence of -OH, -COOH, -NH2, -SO3H, -PR2 and other functional units in the side-chain structure. We have developed two approaches to introduce such active sites: (1) protection-deprotection reactions; and (2) direct reactions of active reagents with the organic side-groups of non-functional poly(organophosphazenes). These methods have been applied both at the molecular level and in the form of reactions carried out only at polymer surfaces. The resultant polymers have special properties that are valuable in the micro-encapsulation of sensitive biological agents; in the formation of hydrophobic, hydrophilic, or adhesive surfaces; in crosslinking reactions; and in the development of solid polymer electrolytes, bio-erodible polymers, pH-triggered hydrogels, polymer blends and interpenetrating polymer networks. Overall, more than 700 different polyphosphazenes are now known, and a large number of these are functional macromolecules targeted for specific property combinations and uses. © 1998 John Wiley & Sons, Ltd.
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  • 49
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    Applied Organometallic Chemistry 12 (1998), S. 707-713 
    ISSN: 0268-2605
    Keywords: polyhedral oligomeric silsesquioxane ; hybrid ; thermoplastic ; polymer ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A diverse and entirely new class of monomer and polymer technology based on polyhedral oligomeric silsesquioxane (POSS) reagents has been developed. POSS reagents are unique in that they are physically large (approx. 15 Å diameter and 1000 amu) and are composed of a robust silicon-oxygen framework that can be easily functionalized with a variety of organic substituents. Appropriate functionalization of POSS cages allows for their incorporation into traditional thermoplastic resins without modification of existing manufacturing processes. The incorporation of POSS segments into linear copolymer systems results in increased glass transition and decomposition temperatures, increased oxygen permeability and reduced flammability and heat evolution, as well as modified mechanical properties relative to conventional organic systems. © 1998 John Wiley & Sons, Ltd.
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  • 50
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    Applied Organometallic Chemistry 12 (1998), S. 667-673 
    ISSN: 0268-2605
    Keywords: polysilanes ; poly(dimethylsiloxane) ; polyphosphazenes ; atom transfer radical polymerization ; controlled/‘living’ radical polymerization ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent advances in the synthesis of block, graft and star polymers containing inorganic macromolecular species are described. Anionic copolymerization techniques were used in the for-­mation of diblock copolymers of poly(styrene-block-methylphenylsilylene) and poly(isoprene-block-methylphenylsilylene) by the ring-opening polymerization of 1,2,3,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasilane initiated by living anionic polystyrene and isoprene respectively. Hydrosilation of an attachable initiator onto telechelic vinyl- or hydrosilyl-terminal or­-pendant poly(dimethylsiloxane) (PDMS) yielded a PDMS macroinitiator. This macroinitiator was used in atom transfer radical polymerization (ATRP) of styrene and isobornyl acrylate to produce ABA triblock copolymers. As a model for graft copolymers from a polyphosphazene backbone, chemical trans-­formation of hexachlorocyclotriphosphazene­resulted in hexafunctional molecules containing either benzyl bromide or bromopropionyl moieties. The initiator 1,1,3,3,5,5-hexakis[4-(2-bromopropionyloxymethyl)phenoxy]cyclotriphosphazene was used in the ATRP of styrene to yield a polymer with a narrow, monomodal molecular weight distribution. Chain extension of this star polymer with isobornyl acrylate is also described. © 1998 John Wiley & Sons, Ltd.
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  • 51
    ISSN: 0268-2605
    Keywords: polymer ; organocobalt ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rearrangement reaction of an organocobalt polymer with cobaltacyclopentadiene moieties in the main chain (1) was carried out to yield a­new polymer bearing (η5-cyclopentadienyl) (η4-­cyclobutadiene)cobalt moieties in the main chain (2). For instance, a polymer (2) containing pure η4-cyclobutadienecobalt units was obtained as a yellow powder in 79% yield by the reaction of 1 in tetrahydrofuran (THF) at 110 °C for 1 h in a sealed tube. The polymer (2) obtained was soluble in organic solvents such as chloroform, THF and N,N-dimethylformamide and was quite stable under air. It showed good thermal stability and a weight loss of 5% was observed at 482 °C by thermogravimetric analysis (TGA). On the other hand, displacement of the triphenylphosphine ligands on the main chain of the organocobalt polymer (1), without rearrangement of the cobaltacyclopentadiene rings, was observed when the reaction was carried out in the presence of appropriate ligands such as P(n-Bu)3. The resulting ligand-exchanged polymer showed different properties in comparison with 1. For instance a polymer bearing tri-n-octylphosphine is soluble in n-hexane, which is a poor solvent for 1. © 1998 John Wiley & Sons, Ltd.
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  • 52
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    Applied Organometallic Chemistry 12 (1998), S. 749-753 
    ISSN: 0268-2605
    Keywords: polymer ; silicon ; gel ; films ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of organic-inorganic polymer hybrids consisting of carbon-carbon and siloxane chains was investigated by radical polymerization of 3-methacryloxypropyltrimethoxysilane (MAS) followed by acid-catalyzed hydrolytic polycondensation. The condensation of poly(3-methacryloxypropyltrimethoxysilane) (S-PMA) of various molecular weights Mn =830-12000 prepared by polyaddition provided transparent and flexible free-standing hybrid gel films. The mechanical properties of these films were highly dependent on the carbon-carbon chain length: with an increase in the carbon-carbon chain length, the elasticity of gel films increased, while the tensile strength and Young's modulus decreased. Hydrolyzability of S-PMA decreased with an increase in the carbon-carbon chain length, resulting in the formation of rubber-like films with flexibility. © 1998 John Wiley & Sons, Ltd.
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  • 53
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    Applied Organometallic Chemistry 12 (1998), S. 755-762 
    ISSN: 0268-2605
    Keywords: poly(vinyl alcohol) (PVA) ; sol-gel ; polymer hybrid ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homogeneous poly(vinyl alcohol) (PVA)-silica gel polymer hybrids were prepared by in-situ hydrolysis of poly(vinyl acetate) (PVAc) in a sol-gel reaction mixture with tetramethoxysilane (TMOS). The degree of hydrolysis was evaluated by FTIR and 13C CP/MAS NMR; it increased with an increase in the acid catalyst and reached 85% with 1.6 ml of 0.1 M HCl. The homogeneity of the polymer hybrids obtained was maintained when the reaction was performed at 60 °C. However, the polymer hybrid became turbid with an increase of the amount of catalyst present when the reaction was conducted at room temperature. The homogeneity of the polymer hybrids obtained was evaluated by nitrogen sorption porosimetry of a porous silica that was obtained by charring the PVA hybrid. The results confirmed the molecular-level dispersion of the PVA in the hybrid. © 1998 John Wiley & Sons, Ltd.
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  • 54
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    Applied Organometallic Chemistry 12 (1998), S. 781-785 
    ISSN: 0268-2605
    Keywords: phosphonium ; polymer ; monomer ; film ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(arylene ether) main-chain phosphonium ionomers were successfully synthesized and characterized. The reaction scheme involved first preparing the poly(arylene ether phosphine oxide) by a nucleophilic step or condensation polymerization of bisphenolates on activated aryl halides, wherein phenyl phosphine oxide was the activating group. High-molecular-weight, tough, film-forming polymers were produced with glass transition temperatures of 200°C or higher. The resulting materials were successfully reduced using phenylsilane in refluxing chlorobenzene. The derived phosphine or phosphine/phosphine oxide copolymer was reacted with alkyl halides to produce the phosphonium salts. The resulting materials showed enhanced hydrophilicity and in some cases could be successfully dispersed in water. In addition, chromophores such as Methyl Orange and Methyl Red were combined with the backbone ionomer to produce new film-forming, ionically linked species. The materials are of general interest for situations where water-dispersible intermediates, e.g. coatings, fiber sizings etc. are required. The phosphonium salts can be converted back to the phosphine oxide in fairly high yields by simple thermal methods and in quantitative yield by chemical methods (e.g. the Wittig reaction). © 1998 John Wiley & Sons, Ltd.
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  • 55
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    Applied Organometallic Chemistry 12 (1998), S. 681-693 
    ISSN: 0268-2605
    Keywords: ceramics ; preceramic polymers ; SiNCB composites ; boron nitride ; boron ; silicon ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Our recent work directed at the design, synthesis, characterization and applications of new types of polyborazylene and polyborosilazane polymers is reviewed with a focus on the use of these polymers as processable precursors to BN and SiNCB composites. A design strategy based on the controlled functionalization of preformed polymers with pendant groups of suitable compositions and crosslinking properties has been employed to yield second-generation dipentylamine-polyborazylene (DPA) and pinacolborane-hydridopolysilazane (PIN-HPZ) polymers, which, unlike the parent polyborazylene (PB) and the borazine-hydridopolysilazane (B-HPZ) polymers, are stable as melts and can be easily melt-spun into polymer fibers. Subsequent pyrolyses of these polymer fibers then provide excellent routes to BN and SiNCB ceramic fibers. © 1998 John Wiley & Sons, Ltd.
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  • 56
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    Applied Organometallic Chemistry 12 (1998), S. 1-12 
    ISSN: 0268-2605
    Keywords: reaction ; morin ; hydroxyflavone ; preconcentration ; sample clean-up ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical procedure for the determination of phenyltin compounds in environmental sample waters was studied. Chromatography of mono-, di- tri-phenyltin (MPT, DPT and TPT) was performed on a reversed-phase C18 column with the mobile phase comprising methanol/10-2 M H3PO4 (80:20 v/v) at pH 3 and UV detection at 214 nm. To enhance the sensitivity of the detection system, the post-column reaction between morin or 3-hydroxyflavone and phenyltin compounds was formed before fluorescence detection. Several parameters affecting the fluorescence intensity were studied systematically, including the optimum condition for the post-column reagent that was also compatible with the eluent. The parameters concerned in this study were the pH, the percentage of Triton X-100, the ratio of fluorigenic reagent to phenyltin compounds and the amount of methanol in the eluent. Detection limits before the preconcentration process were in the region of 1.5 ppb for TPT and 150-250 ppb for MPT and DPT, respectively. Utilizing solid-phase extraction on a C18 cartridge for sample clean-up as well as preconcentration successfully reduced the detection limit of TPT to the level of ng dm-3 and can be applied to seawater analysis. Recovery in the range 95.0-98.0% was obtained by developing the optimum elution profile in the preconcentration step. © 1998 John Wiley & Sons, Ltd.
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  • 57
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 58
    ISSN: 0268-2605
    Keywords: X ray structure ; triphenyltin ; p-ethoxybenzoic acid ; acetylsalicylic acid ; phthalic acid ; salicylaldehydato ; polymer ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenyltin(IV) compounds of p-ethoxybenzoic acid and acetylsalicylic acid contain molecular units with Sn-O bonds and distorted tetrahedral tin centers. The phthalic acid derivative contains two four-coordinate tin atoms between which the phthalic acid unit effectively forms a bridge. The salicylaldehydato compound is polymeric with trigonal bipyramidal tin centers in which the phenyl groups take equatorial positions. The polymerization occurs via the aldehyde oxygen atom bonding to a neighboring tin atom. © 1998 John Wiley & Sons, Ltd.
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  • 59
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    Applied Organometallic Chemistry 12 (1998), S. 25-30 
    ISSN: 0268-2605
    Keywords: adduct ; carboxylate ; Ceratocystis ulmi ; Dutch elm disease ; far-infrared spectroscopy ; fungicide ; Mossbauer spectroscopy ; organotins ; QSAR ; thiazolidin-4-ones ; triphenyltin ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the interest of developing a more effective fungicide to combat Dutch elm disease, our laboratories have synthesized several triphenyltin carboxylates and some 1:1 addition compounds of triphenyltin chloride using 2,3-disubstituted thiazolidin-4-ones as the ligand and screened them in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease, using a shake culture method. Elemental analyses and spectroscopic data indicate that the structures of the carboxy- lates in the solid state are monomeric with a tetrahedral tin atom with the exception of the furan-2-carboxylic acid derivative, which was found to be polymeric. The triphenyltin chloride adducts are trigonal-bipyramidal with the three phenyl groups in the equatorial plane. Far-infrared data indicate that the three phenyl groups are not co-planar. Screening results for both series of organotins indicate that these two classes of compounds are effective inhibitors of Ceratocystis ulmi, with the adducts having a higher activity. The furan-2-carboxylic acid derivative has a markedly decreased activity compared with the other carboxylates and this is attributed to its polymeric structure. © 1998 John Wiley & Sons, Ltd.
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  • 60
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    Applied Organometallic Chemistry 12 (1998), S. 78-78 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 61
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    Applied Organometallic Chemistry 12 (1998), S. 39-46 
    ISSN: 0268-2605
    Keywords: organotin(IV): organosilicon(IV) complexes ; thiosemicarbazones ; antimicrobial studies ; NMR spectra ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R2MCl(TSCZ) and R2M(TSCZ)2 (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and 1H, 13C 29Si and 119Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.
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  • 62
    ISSN: 0268-2605
    Keywords: triarylantimony dichrysanthemate ; plant growth-regulating activity ; crystal structure ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of triarylantimony dichrysanthemate compounds of the type Ar3Sb(O2CR)2 [Ar=C6H5, 4-CH3C6H4, 3-CH3C6H4, -CH3C6H4, 4-ClC6H4; R=4-ClC6H4CH(i-Pr), cis-Cl2C:CH trans-Cl2C:CH] have been synthesized and characterized by elemental analysis, infrared spectra, 1H NMR spectra and mass spectra. Some activities of these compounds in plant growth regulation have been determined. Their results indicate that the derivatives of cis-dichlorochrysanthemic acid and trans-dichlorochrysanthemic acid significantly promote rooting of excised cucumber cotyledons at 10 ppm. An X ray structure determination has been carried out as follows for Ph3Sb(O2CCHCMe2CMe2)2: orthorhombic, space group Pbcn, Z=4, structure solution with 2385 independent reflections, R=0.035. Lattice dimensions at 26 °C: a=15.616(3) Å, b=10.275(2) Å, c=20.201(5) Å, V=3241(2) Å3, ρ=1.302 g cm-3. © 1998 John Wiley & Sons, Ltd.
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  • 63
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    Applied Organometallic Chemistry 12 (1998), S. 59-65 
    ISSN: 0268-2605
    Keywords: cobaltocenium ; ferrocene ; Nafion ; phenytoin ; phenobarbital ; square-wave voltammetry ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two different cationic redox labels, i.e. a ferroceneammonium ion and a cobaltocenium ion, were covalently attached to two antiepileptics, phenytoin and phenobarbital, respectively. The two labeled drugs possess distinct standard redox potentials of 0.39 V for the phenytoin derivative and -0.92 V for phenobarbital derivative (vs Ag/AgCl, Cl- 0.05 M) at a carbon paste electrode. After preconcentration in a polyanionic Nafion-loaded carbon paste electrode the positively charged labeled phenytoin and phenobarbital derivatives could be simultaneously detected in concentration ranges which were relevant to the therapeutic ranges of the antiepileptics, with a view to a future dual-analyte immuno- assay. Square-wave voltammetry permitted detection limits of 5×10-8 M (for the phenytoin derivative) and 2.5×10-8 M (for the phenobarbital derivative) for non-simultaneous detection. © 1998 John Wiley & Sons, Ltd.
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  • 64
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    Applied Organometallic Chemistry 12 (1998), S. 145-145 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 65
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    Applied Organometallic Chemistry 12 (1998), S. 67-75 
    ISSN: 0268-2605
    Keywords: organotin ; tributyltin ; tributyltin oxide ; tetrabutyltin ; degradation ; bioassay ; bioindicator ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The growth response of the alga Chlorella kessleri and the euglenoid Euglena gracilis has been studied as a model system to determine the effects of a tin salt (SnCl4·5H2O) and of some organotin (OT) derivatives, namely tetrabutyltin (TeBT), tributyltin (TBT) and tributyltin oxide (TBTO). Abiotic degradation was studied as well. Cells were exposed to a toxicity series (0-50 μg/mL-1) for the four chemicals in seven-day bioassays. Both microorganisms are tolerant of the inorganic salt, but growth inhibition was significant for all OT compounds, and especially large for TBT and TBTO. Although C. kessleri and E. gracilis are known to be tolerant towards metals and organic chemicals, the present results show that both are sensitive to organotin compounds: the inhibition of the growth was greater for C. kessleri. © 1998 John Wiley & Sons, Ltd.
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  • 66
    ISSN: 0268-2605
    Keywords: surfactants ; carbohydrate ; carbosilane ; silane ; wetting ; surface tension ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of carbohydrate surfactants bearing carbosilane, silane, polysilane and non-permethylated siloxane moieties is described. These surfactants consist of three structural elements: (1) a silicon-containing moiety, (2) a spacer and (3) a carbohydrate unit. Additionally two different types of mixed structures have been synthesized: (a) single-chained carbosilane-siloxane surfactants and (b) double-chained combinations of carbo- silanes, silanes and siloxanes. The wetting behaviour of the key intermediates, the allyl glycidyl derivatives, has been investigated by static surface tension (γlv, σ) and wetting tension (γsv-γsl, α) measurements on a non-polar perfluorinated surface (FEP® plate). The contact angles obtained for these pure liquids are not a linear function of the surface tension but depend on the polarity of the substructures. © 1998 John Wiley & Sons, Ltd.
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  • 67
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    Applied Organometallic Chemistry 12 (1998), S. 79-85 
    ISSN: 0268-2605
    Keywords: organic tellurium compounds ; polycondensation ; amino groups ; polyamides ; polyurea ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several new and known organic tellurium compounds containing amino groups (i.e. ArTeBr3, Ar2Te2 and Ar2Te, where Ar= 4-NH2C6H4, 2-NH2C6H4, 4-CH3CONHC6H4 or 2-NH2-5-NO2-C6H3) were prepared by reacting aminoarylmercury chlorides with tellurium tetrabromide in glacial acetic acid. Bis(4-aminophenyl) telluride and bis(2-amino-5-nitrophenyl) telluride were polymerized with aromatic and aliphatic diacid chlorides (i.e. terephthaloyl chloride and sebacoyl chloride), as well as with toluene di-isocyanate, leading to new organic tellurium polyamides and polyurea. All organic tellurium compounds and their condensation polymers were characterized by elemental analyses, IR, 1H and 13C NMR, and mass spectroscopy. The thermal stabilities of the resulting polymers were determined by thermogravimetric and derivative thermogravimetric techniques. © 1998 John Wiley & Sons, Ltd.
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  • 68
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    Applied Organometallic Chemistry 12 (1998), S. 87-97 
    ISSN: 0268-2605
    Keywords: antitumor ; metal complexes ; amine-carboxyborane ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The amine carboxyborane metal complexes, tetrakis - μ - (trimethylamine - boranecarbo - xylato)acetonitrile dicopper(II) and bis-μ- (morpholine-boranecarboxylato)zinc(II) dihydrate demonstrated cytotoxic activity against human Tmolt3, HeLa-S3 and MB-9812 cell growth.Tetrakis-μ-(trimethylamine-boranecarboxylato)-acetonitrile dicopper(II) and bis - μ - (morpholine - boranecarboxylato)zinc (II) dihydrate inhibited L1210 DNA, RNA and protein syntheses, with greatest inhibitory effects on DNA synthesis. The reduction in DNA synthesis correlates well with inhibition of de novopurine synthesis and the key enzymes involved in this pathway, i.e. IMP dehydrogenase and PRPP amido transferase. These compounds were also observed to induce DNA strand scission but did not appear to intercalate between base pairs of DNA, alkylate bases or cause cross-linking of the strands of DNA. Tetrakis-μ-(trimethylamine - boranecarboxylato)acetonitrile dicopper(II) also demonstrated the ability to inhibit L1210 DNA topoisomerase II activity. © 1998 John Wiley & Sons, Ltd.
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  • 69
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    Applied Organometallic Chemistry 12 (1998), S. 109-119 
    ISSN: 0268-2605
    Keywords: bioconcentration ; toxicity ; TBTCl ; tilapia ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acute toxicity (96 h) and bioconcentration experiments of tributyltin chloride (TBT) in tilapia were conducted in an aqueous solution with salinity of 15‰, and a toxicity mechanism has been suggested. The 96-h LC50 was 3.80 μg Sn l-1. Bioconcentration factors in different tissues increased in the order muscle〈gill〈viscera. Studies on the metabolism of TBT showed that it can be easily degraded to DBT (dibutyltin) in these tissues. Further degradation of DBT to MBT (monobutyltin) was much more difficult. A mesocosm was used for the first time to study the toxicity of TBT in tilapia. The result demonstrated that the TBT bioconcentration curve changed with the initial concentrations of TBT but the order of bioconcentration in the tissues did not change. © 1998 John Wiley & Sons, Ltd.
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  • 70
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    Applied Organometallic Chemistry 12 (1998), S. 99-107 
    ISSN: 0268-2605
    Keywords: phenyltin ; model membrane ; hemolysis ; fluorescence ; 1H NMR ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenyltin compounds are known to be biologically active. Their chemical structure suggests that they are likely to interact with the lipid fraction of cell membranes. Using fluorescence and NMR techniques, the effect of phenyltin compounds on selected regions of model lipid bilayers formed from phosphatidylcholine was studied. The polarization of N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) dipalmitoyl-L-phosphatidylethanolamine and desorption of praseodymium ions was used to probe the polar region, whereas the polarization of 1 - (4 - trimethylammoniumphenyl) - 6 - phenyl - 1,3,5-hexatriene p-toluenesulfonate measured the hydrophobic core of the membrane. In addition, changes in the N-(5-fluoresceinthiocarbanoly)dipalmitoyl - L - α - phosphatidyl - ethanolamine fluorescence intensity indicated the amount of charge introduced by organotin compounds to the membrane surface. There were no relevant changes of measured parameters when tetraphenyltin was introduced to the vesicle suspension. Diphenyltin chloride causes changes of the hydrophobic region, whereas the triphenyltin chloride seems to adsorb in the headgroup region of the lipid bilayer. When the hemolytic activity of phenyltin compounds was measured, triphenyltin chloride was the most effective whereas diphenyltin chloride was much less effective. Tetraphenyltin causes little damage. Based on the presented data, a correlation between activity of those compounds to hemolysis (and toxicity) and the location of the compound within the lipid bilayer could be proposed. In order to inflict damage on the plasma membrane, the compound has to penetrate the lipid bilayer. Tetraphenyltin does not partition into the lipid fraction; therefore its destructive effect is negligible. The partition of the compound into the lipid phase is not sufficient enough, by itself, to change the structure of the lipid bilayer to a biologically relevant degree. The hemolytic potency seems to be dependent on the location of the compound within the lipid bilayer. Triphenyltin chloride which adsorbs on the surface of the membrane, causes a high level of hemolysis, whereas diphenyltin chloride, which penetrates much deeper, seems to have only limited potency. © 1998 John Wiley & Sons, Ltd.
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  • 71
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    Applied Organometallic Chemistry 12 (1998), S. 121-128 
    ISSN: 0268-2605
    Keywords: MMT ; soils ; interactions ; Fourier-transform IR ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and headspace analysis gas-phase infrared spectroscopy (HAGIS) were used to investigate interactions between soils and the gasoline additive methylcyclopentadienylmanganese tricarbonyl (MMT). Various soil samples, as well as alumina and silica substrates, were studied. Each substrate exhibited a splitting or broadening of the degenerate e ν(CO) band of MMT, suggesting an interaction involving one or two of the CO ligands. The adsorption was shown to be reversible under relatively mild conditions using HAGIS. The proposed interaction is of the Brønsted type, involving the carbonyl oxygen and a surface-bound water or hydroxyl group. This type of interaction could stabilize MMT by inhibiting photo-ejection of CO ligands, a common first step in the decomposition of organometallic carbonyl compounds such as MMT. © 1998 John Wiley & Sons, Ltd.
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  • 72
    ISSN: 0268-2605
    Keywords: trimethylantimony ; molecular rearrangement ; demethylation ; speciation ; hydride generation ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The method of hydride generation for the speciation of antimony compounds was examined with respect to the problem of molecular "rearrangement'. Specifically, demethylation of trimethylstilbine during the analysis of trimethylantimony dichloride (Me3SbCl2) was studied. Previously published observations that enhanced demethylation takes place as a result of inadequate preconditioning of the analytical apparatus were found to be not reproducible. However, demethylation was enhanced as the pH decreased when using two different analytical methods: semi-continuous flow hydride generation-gas chromatography-atomic absorption spectrometry (HG- GC-AAS), and batch-type hydride generation- gas chromatography-inductively coupled plasma mass spectrometry (HG-GC-ICP MS). Applications of the hydride generation method to environmental samples revealed differences in analytical results at high and low pH, and enhanced demethylation taking place because of the matrix in a fungal extract sample. The authors recommend that researchers using the method of hydride generation for antimony compounds carefully test the reaction conditions with standard compounds and use the method of standard addition only. © 1998 John Wiley & Sons, Ltd.
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  • 73
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    Applied Organometallic Chemistry 12 (1998), S. 145-145 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 74
    ISSN: 0268-2605
    Keywords: arsenobetaine ; arsenocholine ; trimethylarsine oxide ; tetramethylarsonium iodide ; organic arsenic compound ; arsenite ; arsenate ; marine organisms ; cytotoxicity ; chromosomal aberration ; sister chromatid exchange (SCE) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium iodide, which are contained in marine fishery products, were examined for their potencies on cell growth inhibition, chromosomal aberration and sister chromatid exchange (SCE). Arseno- betaine, the major water-soluble organic arsenic compound in marine animals, exhibited very low cytotoxicity towards mammalian cells. This compound showed no cell growth inhibition at a concentration of 10 mg cm-3 and the cytotoxicity was lower than 1/14 000th of that of sodium arsenite and 1/1600th of that of sodium arsenate towards BALB/c 3T3 cells. The chromosomal aberrations caused by arsenobetaine at a concentration of 10 mg cm-3 consisted mainly of chromatid gaps and chromatid breaks, but in this concentration chromosomal breakage owing to its osmotic pressure is likely to be considerable. No SCE was observed at a concentration of 1 mg cm-3. Arsenocholine and trimethylarsine oxide also showed no cell growth inhibited at a concentration of 10 mg cm-3. However, tetramethylarsonium iodide inhibition the growth of BALB/c 3T3 at a concentration of 8 mg cm-3. These compounds exhibited a low ability to induce chromosomal aberrations at a concentration range of 2-10 mg cm-3 and no SCE was observed at a concentration of 1.0 mg cm-3. These results suggested that the major and minor organic arsenic compounds contained in marine fishery products are much less cytotoxic inorganic arsenic, methylarsonic acid and dimethylarsinic acid. © 1998 John Wiley & Sons, Ltd.
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  • 75
    ISSN: 0268-2605
    Keywords: laser-assisted chemical vapor deposition ; SnO2 ; SnBr4 ; copper(II) acetate ; gas sensors ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser-assisted chemical vapor deposition (LCVD) was utilized to produce SnO2 films from SnBr4 plus air, O2 or N2O. SnO2 films were successfully generated using either 222 or 308 nm laser pulses but there was evidence for film contamination when using less than 60 mJ/pulse laser energies at 222 nm. Films were characterized using ultraviolet absorption spectroscopy; the spectra of films with impurities resembled the spectrum of SnBr4. AFM images were obtained which indicated that this LCVD route produced small and fairly uniform SnO2 grains which were 50-100 nm in size. Multiphoton ionization spectroscopy was used to verify that the dissociation of a film dopant precursor, copper(II) acetate, produced gas-phase copper atoms under conditions similar to those used in film deposition experiments. The deposition of SnO2 from SnBr4 plus an oxidant was found to be more efficient than from di-n-butyl tin diacetate but films produced via this new LCVD route, including those doped with copper, were found to be much less sensitive in preliminary gas-sensing screening. © 1998 John Wiley & Sons, Ltd.
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  • 76
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    Applied Organometallic Chemistry 12 (1998), S. 155-160 
    ISSN: 0268-2605
    Keywords: tungsten trioxide ; electrochromism ; thin films ; chemical vapor deposition (CVD) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystalline and amorphous thin films of tungsten(VI) oxide can be prepared by chemical vapor deposition using a variety of volatile precursors below 500 °C. Deposition parameters for preparation of WO3 films from tungsten hexacarbonyl [W(CO)6], tungsten hexafluoride (WF6), tungsten ethoxides [W(OEt)x, x = 5, 6] and tetra(allyl)tungsten [W(η3-C3H5)4] are summarized. The electrochromic behavior of these films is comparable with that observed for WO3 films prepared by evaporation, sputtering and electrodeposition. © 1998 John Wiley & Sons, Ltd.
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  • 77
    ISSN: 0268-2605
    Keywords: chemical vapor deposition ; platinum ; palladium ; rhodium ; heterogeneous catalysts ; fluidized bed ; MOCVD ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new one-step method, entitled fluidized-bed metal-organic chemical vapor deposition (FBMOCVD) of preparing highly dispersed metal-supported catalysts is reported. The following complexes were studied and used as CVD precursors in presence of H2: [Rh(μ-Cl)(CO)2]2, Rh(allyl)3, Rh(acac)(CO)2, Pd(allyl)(hfac), Pd(allyl)(Cp), Pt(COD)(CH3)2. (acac, acetylacetonato; hfac, hexafluoroacetylacetonato; Cp, cyclopentadienyl; COD, cyclooctadienyl). In a first approach, depositions on planar substrates were carried out to establish the best experimental conditions to obtain good-quality deposits. X-ray diffraction, X-ray photo-electron spectroscopy and electron microprobe studies were realized on the resulting thin films. Analyses of the products contained in the gas phase after and during deposition were performed by mass spectrometry and GC-MS. Finally, catalysts prepared by FBMOCVD were characterized by transmission electron microscopy-energy dispersion spectroscopy (TEM-EDS), metal-loading determinations and specific-surface measurements (BET). Dispersed nanosized aggregates were obtained, showing high activities in alkene hydrogenation and alcohol hydrocarbonylation. © 1998 John Wiley & Sons, Ltd.
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  • 78
    ISSN: 0268-2605
    Keywords: Metal-organic chemical vapor deposition (MOCVD) ; precursors ; titanium ; vanadium ; carbonitride ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ceramic thin films containing titanium, vanadium, carbon, oxygen and nitrogen were obtained on steel substrates at 873 K, under nitrogen and helium gases and at low pressure, by chemical vapor deposition (CVD) from two organometallic precursors, CpTiCl2N(SiMe3)2 and Cp2VMe2 (Cp, cyclopentadienyl). Independent TG-DTA-MS and CVD studies of the two precursors showed their ability to co-decompose within compatible temperature and pressure domains. The mechanism of the reactions occurring inside the CVD apparatus was also approached by GC-MS and NMR analyses of the condensed decomposition products. CVD conducted under He gas confirmed that the formation of nitride resulted from the nitrogen atoms of the precursor, but the nitrogen content in the films remained lower than approx. 5%. Higher nitrogen contents (up to 12%) were only obtained when using ammonia as a carrier gas. Both precursors being air- and moisture-sensitive, high-purity CVD equipment was used to reduce oxycarbide formation. © 1998 John Wiley & Sons, Ltd.
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  • 79
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    Applied Organometallic Chemistry 12 (1998), S. 189-199 
    ISSN: 0268-2605
    Keywords: single-source precursor ; tetrakis(diethylamido)chromium ; pyrolysis mechanism ; MOCVD ; low-temperature deposition ; chromium carbonitride thin films ; hard metallurgical coatings ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amorphous chromium carbonitride coatings with a low nitrogen content (3-8 at%) were deposited by low-pressure MOCVD in the temperature range 573-793 K using Cr(NEt2)4 as single-source precursor. This poor nitrogen incorporation is in agreement with the trends predicted by thermochemical calculations. XPS data, resistivity measurements and annealing experiments suggest that the films grown at 573 K are contaminated by organic species due to incomplete elimination of the ligands. The films deposited at higher temperature crystallize upon annealing at 873 K to form an orthorhombic ternary chromium carbonitride phase. The major volatile by-products of the MOCVD reaction were analyzed by 1H and 13C NMR. Their amount and the quasi-equimolar EtN=CHMe/HNEt2 ratio suggest that most of the NEt2 ligands are removed by a stepwise mechanism which probably occurs with other diethylamido complexes of transition metals when they are used as single-source precursors in MOCVD. The incorporation of the metalloid elements in the film is discussed in comparison with recent literature data. © 1998 John Wiley & Sons, Ltd.
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  • 80
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    Applied Organometallic Chemistry 12 (1998), S. 201-220 
    ISSN: 0268-2605
    Keywords: MOCVD ; molybdenum oxycarbide ; chromium oxycarbide ; coating ; kinetics ; microstructure ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A review of the coating kinetics of molybdenum and chromium oxycarbides and a study on the properties of deposited films are reported. Molybdenum carbonyl, chromium carbonyl and their mixture were used to prepare coatings at temperatures between 170 and 450 °C on SS304 or SiC substrates by a process of metal-organic chemical vapor deposition (MOCVD). The processing parameters of the coatings, such as the evaporation of precursors, coating pressure and temperature, are discussed along with the coating rates, compositions and other microstructural information, so to reveal the kinetics of the coating process on two different substrates. In addition, the chemical composition, crystalline phases and microstructure of the coatings obtained in various conditions are presented with the evidence interpreted by various electron-microscopic and spectroscopic techniques, including XRD, EDS, EPMA and XPS. The dependence of some properties, such as hardness, adhesive strength and corrosive resistance of the coatings on SS 304, on their composition and the deposited phases, i.e. as a function of coating temperature and pressure, is reviewed. © 1998 John Wiley & Sons, Ltd.
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  • 81
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    Applied Organometallic Chemistry 12 (1998), S. 221-236 
    ISSN: 0268-2605
    Keywords: MOCVD ; barium ; liquid delivery ; mixed-metal species ; aerosol-assisted CVD ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conventional MOCVD techniques require molecules displaying volatility and constant vapor pressure. Metal oxide precursors, i.e., β-diketonates, or classical or functionalized metal alkoxides are mostly solids. The various approaches used to tailor volatility are discussed with barium derivatives as an example. The relationships between sublimation temperature and molecular weight suggest that volatility can be optimized on the basis of molecular weight.   Aerosol-assisted CVD (AACVD) can use a larger range of precursors since volatility is no longer crucial. The solvent is an undesired ballast in a CVD process. High solubility of the precursors in the selected solvent is thus desirable. ‘Stability’ here includes the absence of precipitation which would change the stoichiometry of the feed solution for multicomponent oxides. Precipitation is often promoted by hydrolysis; stability toward moisture is thus desirable. The use of mixtures of precursors based on different ligands (β-diketonates, β-ketoesterates, alkoxides) can lead to ligand exchange reactions giving homometallic species, sometimes of low solubility, or mixed-metal species by self-assembly, thus improving solubility and stability toward moisture. These aspects are illustrated in compositions related to high-Tc superconductors. Novel copper, yttrium, cerum(IV), barium-copper, yttrium-copper and praseodynium-copper species are reported. © 1998 John Wiley & Sons, Ltd.
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  • 82
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    Applied Organometallic Chemistry 12 (1998), S. 293-293 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 83
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 84
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    Applied Organometallic Chemistry 12 (1998), S. 294-294 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 85
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 86
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    Applied Organometallic Chemistry 12 (1998), S. 295-296 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 87
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    Applied Organometallic Chemistry 12 (1998), S. 296-296 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 88
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Applied Organometallic Chemistry 12 (1998), S. 296-297 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
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    Applied Organometallic Chemistry 12 (1998), S. 297-297 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 91
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 92
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    Applied Organometallic Chemistry 12 (1998), S. 298-298 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 93
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    Applied Organometallic Chemistry 12 (1998), S. 237-241 
    ISSN: 0268-2605
    Keywords: tin ; iodomethane ; solubilization ; methyltin species ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dissolution of tin metal by iodomethane-water mixtures has been studied and the influence of several parameters on both the extent and rate of reaction investigated. The rate-determining step shows a pseudo-first-order dependence on iodomethane (CH3I). The reaction is strongly dependent upon both water and oxygen. The activation energy of only 16 kJ mol-1 is interpreted in terms of a facile bond-breaking and making process at the metal surface, generating methyltin species. Analysis by hydride generation and GC-AA confirmed the formation of methylated species ranging from monomethyl- to tetramethyl-tin; inorganic tin (from hydrolysis) was the major form, however. These findings are similar to those made earlier by us on the solubilization of arsenic from GaAs by alkyl halide-water mixtures, and a similar multi-step scheme is proposed. © 1998 John Wiley & Sons, Ltd.
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  • 94
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    Applied Organometallic Chemistry 12 (1998), S. 243-251 
    ISSN: 0268-2605
    Keywords: arsenic ; speciation ; algae ; Fucus gardneri ; arsenosugar ; high-performance liquid chromatography (HPLC) ; inductively coupled plasma-mass spectrometry (ICP-MS) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenic speciation in a brown alga, Fucus gardneri, collected in Vancouver, B.C., Canada, was carried out by using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). Hydride generation-atomic absorption spectrometry (HG-AAS) was used for total arsenic determination. The relative amounts of some arsenosugars 1 in growing tips are found to be different in comparison with the remainder of the plant. Fucus samples collected in summer contain 9 ppm of total arsenic. Most of the arsenic species are extractable. Fucus samples collected in winter contain relatively higher amounts of arsenic, 16-22 ppm, but only low amounts of this are extractable. © 1998 John Wiley & Sons, Ltd.
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  • 95
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    Applied Organometallic Chemistry 12 (1998), S. 253-256 
    ISSN: 0268-2605
    Keywords: disilane ; gas source MBE ; synchrotron radiation ; silicon hydride ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Surface hydrogen and growth mechanisms are investigated for synchrotron radiation (SR)-assisted gas source molecular beam epitaxy (SR-GSMBE) using Si2H6 on the Si(100) surface in the low-temperature region. The surface silicon hydrides (deuterides) are monitored in situ during the epitaxial growth by means of infrared reflection absorption spectroscopy with a Si(100) substrate and a CoSi2 buried metal layer. It is concluded that the chemisorption of gas-phase reactive species such as SiHn and H generated by SR irradiation and the subsequent hydrogen desorption are the key mechanisms of SR-GSMBE at low substrate temperatures. © 1998 John Wiley & Sons, Ltd.
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  • 96
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    Applied Organometallic Chemistry 12 (1998), S. 257-264 
    ISSN: 0268-2605
    Keywords: Rochow reaction ; cesium chloride ; rubidium chloride ; silicon impurities ; action of promoters ; scanning electron microscopy (SEM) ; energy-dispersive X-ray spectroscopy (EDX) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cesium chloride- and rubidium chloride-promoted Rochow contact masses based on both technical-grade and highly pure silicon have been investigated in the Rochow reaction and by REM/EDX surface analysis. The alkali-salt promoters seem to act analogously to the well-known zinc promoter, by localizing the reaction to distinct reactive areas and keeping free the surface area for the reaction, probably for the formation of catalytically active Cu-Si surface species. The alkali salts exhibited their promoting action only in combination with the impurities within the technical-grade silicon. Otherwise, they acted as blocking poisons. The promoter action of alkali chlorides in contact masses based on technical-grade silicon is possibly connected with the formation of salt melts, containing alkali chlorides and impurities. These melts, analogously to zinc chloride, could dissolve oxidic impurities from the silicon surface which otherwise would enhance the blocking of potentially active surface by extensive copper deposition. © 1998 John Wiley & Sons, Ltd.
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  • 97
    ISSN: 0268-2605
    Keywords: carbohydrate surfactants ; wetting behaviour ; siloxane ; silane ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The wetting behaviour of carbohydrate surfactants bearing siloxane, carbosilane, polysilane or silane moieties has been investigated. By static surface tension (γlv, σ) and wetting tension (γsv-γsl, α) measurements on a non-polar perfluorinated surface (FEP®), the contact angles of aqueous surfactant solutions above the critical micelle formation concentration (cmc) were determined. Surface tension and wetting tension react independently on defined changes in the chemical structure of the surfactant molecules. Siloxane surfactants reduce the surface tension most effectively, whereas for a neopentyl-substituted silane derivative the lowest solid/liquid interfacial tension was found. The data for isomeric siloxanes, carbosilanes and silanes suggest that donor-acceptor forces at solid interfaces have a maximum range of about 4.5 Å. © 1998 John Wiley & Sons, Ltd.
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  • 98
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    Applied Organometallic Chemistry 12 (1998), S. 277-284 
    ISSN: 0268-2605
    Keywords: carboxylation ; methane ; carbon monoxide ; ytterbium(III) acetate ; manganese(II) acetate ; sodium hypochlorite ; acetic acid ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method of synthesis of acetic acid in water has been developed from the carboxylation of methane with carbon monoxide using lanthanide catalysts. Ytterbium(III) acetate has been found to be the most active catalyst among the compounds of the lanthanide series in the carboxylation reaction of methane with carbon monoxide. Sodium hypochlorite or hydrogen peroxide was used as the oxidant in this reaction. Sodium hypochlorite exhibited more favorable activity than hydrogen peroxide in the reaction. The catalytic activity was improved by the addition of transition-metal salts such as manganese(II) acetate. The best result has been found at a ratio of manganese(II) acetate to ytterbium(III) acetate of 1:10. The optimum reaction conditions (reaction temperature, 40 °C; time, 20 h; methane, 20 atm; carbon monoxide, 5 atm) have been obtained. © 1998 John Wiley & Sons, Ltd.
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  • 99
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    Applied Organometallic Chemistry 12 (1998), S. 298-299 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 100
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    Applied Organometallic Chemistry 12 (1998), S. 285-291 
    ISSN: 0268-2605
    Keywords: mushroom ; arsenic speciation ; HPLC-ICP-MS ; dimethylarsinic acid ; arsenobetaine ; trimethylarsine oxide ; toxicological evaluation ; soil contamination ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Samples of the edible mushroom Laccaria amethystina, which is known to accumulate arsenic, were collected from two uncontaminated beech forests and an arsenic-contaminated one in Denmark. The total arsenic concentration was 23 and 77 μg  As g-1 (dry weight) in the two uncontaminated samples and 1420 μg As g-1 in the contaminated sample. The arsenic species were liberated from the samples using focused microwave-assisted extraction, and were separated and detected by anion- and cation-exchange high-performance liquid chromatography with an inductively coupled plasma mass spectrometer as arsenic-selective detector. Dimethylarsinic acid accounted for 68-74%, methylarsonic acid for 0.3-2.9%, trimethylarsine oxide for 0.6-2.0% and arsenic acid for 0.1-6.1% of the total arsenic. The unextractable fraction of arsenic ranged between 15 and 32%. The results also showed that when growing in the highly arsenate-contaminated soil (500-800 μg As g-1) the mushrooms or their associated bacteria were able to biosynthesize dimethylarsinic acid from arsinic acid in the soil. Furthermore, arsenobetaine and trimethylarsine oxide were detected for the first time in Laccaria amethystina. Additionally, unidentified arsenic species were detected in the mushroom. The finding of arsenobetaine and trimethylarsine oxide in low amounts in the mushrooms showed that synthesis of this arsenical in nature is not restricted to marine biota. In order to minimize the toxicological risk of arsenic to humans it is recommended not to consume Laccaria amethystina mushrooms collected from the highly contaminated soil, because of a genotoxic effect of dimethylarsinic acid observed at high doses in animal experiments. © 1998 John Wiley & Sons, Ltd.No Abstract.
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