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  • 11
    Electronic Resource
    Electronic Resource
    Enhanced Evolvability in Immunoglobulin V Genes Under Somatic Hypermutation (1999)
    Springer
    Journal of molecular evolution 49 (1999), S. 23-26 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Genome evolution — Adaptability — Somatic hypermutation — Affinity maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Darwinian theory requires that mutations be produced in a nonanticipatory manner; it is nonetheless consistent to suggest that mutations that have repeatedly led to nonviable phenotypes would be introduced less frequently than others—if under appropriate genetic control. Immunoglobulins produced during infection acquire point mutations that are subsequently selected for improved binding to the eliciting antigen. We and others have speculated that an enhancement of mutability in the complementarity-determining regions (CDR; where mutations have a greater chance of being advantageous) and/or decrement of mutability in the framework regions (FR; where mutations are more likely to be lethal) may be accomplished by differential codon usage in concert with the known sequence specificity of the hypermutation mechanism. We have examined 115 nonproductively rearranged human Ig sequences. The mutation patterns in these unexpressed genes are unselected and therefore directly reflect inherent mutation biases. Using a χ2 test, we have shown that the number of mutations in the CDRs is significantly higher than the number of mutations found in the FRs, providing direct evidence for the hypothesis that mutations are preferentially targeted into the CDRs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006530
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  • 12
    Electronic Resource
    Electronic Resource
    The urate oxidase gene of Drosophila pseudoobscura and Drosophila melanogaster: Evolutionary changes of sequence and regulation (1992)
    Springer
    Journal of molecular evolution 34 (1992), S. 62-77 
    Details
    ISSN: 1432-1432
    Keywords: Urate oxidase ; Drosophila pseudoobscura ; Drosophila melanogaster ; Nucleotide sequence ; Evolutionary comparison ; Gene regulation ; Malpighian tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The urate oxidase (UO) transcription unit of Drosophila pseudoobscura was cloned, sequenced, and compared to the UO transcription unit from Drosophila melanogaster. In both species the UO coding region is divided into two exons of approximately equal size. The deduced D. pseudoobscura and D. melanogaster UO peptides have 346 and 352 amino acid residues, respectively. The nucleotide sequences of the D. pseudoobscura and D. melanogaster UO protein-coding regions are 82.2% identical whereas the deduced amino acid sequences are 87.6% identical with 42 amino acid changes, 33 of which occur in the first exon. Although the UO gene is expressed exclusively within the cells of the Malpighian tubules in both of these species, the temporal patterns of UO gene activity during development are markedly different. UO enzyme activity, UO protein, and UO mRNA are found in the third instar larva and adult of D. melanogaster but only in the adult stage of D. pseudoobscura. The intronic sequences and the extragenic 5′ and 3′ flanking regions of the D. pseudoobscura and D. melanogaster UO genes are highly divergent with the exception of eight small islands of conserved sequence along 772 by 5′ of the UO protein-coding region. These islands of conserved sequence are possible UO cis-acting regulatory elements as they reside along the 5′ flanking DNA of the D. melanogaster UO gene that is capable of conferring a wild-type D. melanogaster pattern of UO regulation on a UO-lacZ fusion gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00163853
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  • 13
    Electronic Resource
    Electronic Resource
    Komplexe Zusammenhänge zwischen Eigenschaften und Strukturparametern von Elektrodengläsern (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 839-850 
    Details
    ISSN: 1434-4475
    Keywords: Electrode glasses ; Principal Component Analysis ; Cluster analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Cluster Analysis has been shown to be partially suitable for the classification of glasses. The expansion of the clusters on theSeger's diagram allows an investigation of the influence of the different glass components. Variation of the SiO2 content results in a smaller change of properties than variation of the Na2O/RO relationship. Principal Component Analysis is convenient for showing correlations between the composition of the examined glasses, the glass structure parameters, and the different electrode properties. Properties of electrodes are mostly influenced by the content of Na2O and by the kind of the divalent cations. In contrast thereto structure parameters become basically determined by the content of SiO2 and RO. The field strength of the divalent cations plays the decisive roll again.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00811003
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  • 14
    Electronic Resource
    Electronic Resource
    Calmodulin-like activity in a mineralising tissue: The rat molar tooth germ (1981)
    Springer
    Calcified tissue international 33 (1981), S. 545-548 
    Details
    ISSN: 1432-0827
    Keywords: calmodulin ; calcium ; mineralisation ; tooth germ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Calmodulin, a calcium binding protein, has been implicated in the regulation of many calcium-dependent biological processes. Since calcium has an important role in hard tissue genesis, both at intra- and extracellular levels, we anticipate that calcium binding proteins may modulate this process. The present study investigated a mineralising tissue, the rat molar tooth germ, to determine the presence of calmodulin-like activity. A heat-treated cell-free extract of tooth germs provided enhancement of Ca2+-dependent Mg2+-ATPase and 3′:5′-nucleotide phosphodiesterase activity. No enhancement occurred in the absence of calcium or in the presence of trifluoperazine. SDS-polyacrylamide gel electrophoresis of this extract revealed a protein band of approximately 18,000 mol. wt. These findings indicate the presence of calmodulin-like activity in rat molar tooth germs and support the proposal that calcium and calcium binding proteins, in particular calmodulin, have a major regulatory role in the biology of mineralising tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409487
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  • 15
    Electronic Resource
    Electronic Resource
    The Physical Tourist¶Scientific Travels in the Irish Countryside (2000)
    Springer
    Physics in perspective 2 (2000), S. 313-326 
    Details
    ISSN: 1422-6960
    Keywords: Key words. History of science; Ireland; Rosse Telescope; St. Patrick's College; Birr Demense; Irish National Museum (Galway); Giant's Causeway.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Newly-prosperous Ireland has a number of sites which the scientific traveller can visit. There are apparatus museums at Birr and Maynooth, and a collection of early apparatus at the physics department of the Irish National University in Galway. The main attraction at Birr is the Rosse Telescope, with its 6-ft diameter speculum, built in the 1840s, and recently refurbished. Travellers to Northern Ireland can see applied geology at the Giant's Causeway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000160050048
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  • 16
    Electronic Resource
    Electronic Resource
    New ways of determining structural groups in brown coals and their bioconversion products by FT IR spectroscopy (2000)
    Springer
    Applied microbiology and biotechnology 54 (2000), S. 681-685 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract New methods of determining the structural groups —COOH and —CH2— have been developed. The investigation of carboxyl groups is possible both after derivatization with p-fluorophenacylbromide and by quantitative interpretation of the Fourier transform infrared (FT IR) spectra. There exists a linear relationship between the results of these two methods that is generally valid for the analysis of all brown coal components. The maximum extinction coefficient of the symmetric stretching vibration band of the CH2 groups has been determined using model substances. This allows quantification of this structural group directly from the FT IR spectrum. The results agree with the contents of methylene groups as determined by 13C-cross polarization–magic angle spinning–nuclear magnetic resonance (13C CPMAS NMR) spectroscopy. Using these methods, the COOH and CH2 groups contained in brown coals of the North Rhine region and in their bioconversion products have been quantified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530000419
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  • 17
    Electronic Resource
    Electronic Resource
    Characterization of rice α-amylase isozymes expressed by Saccharomyces cerevisiae (1995)
    Springer
    Applied microbiology and biotechnology 43 (1995), S. 1050-1055 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Two rice α-amylase isozymes, AmylA and Amy3D, were produced by secretion from genetically engineered strains of Saccharomyces cerevisiae. They have distinct differences in enzymatic characteristics that can be related to the physiology of the germinating rice seed. The rice isozymes were purified with immunoaffinity chromatography. The pH optima for amy3D (pH optimum 5.5) and Amy1A (pH optimum 4.2) correlate with the pH of the endosperm tissue at the times in rice seedling development when these isozymes are produced. Amy3D showed 10–14 times higher reactivity to oligosaccharides than Amy1A. Amy1A, on the other hand, showed higher reactivity to soluble starch and starch granules than Amy3D. These results suggest that the isozyme Amy3D, which is expressed at an early stage of germination, produces sugars from soluble starch during the early stage of seed germination and that the isozyme Amy1A works to initiate hydrolysis of the starch granules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00166924
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  • 18
    Electronic Resource
    Electronic Resource
    Effect of in situ post-deposition annealing on the formation of α-In2Se3 thin films grown by elemental evaporation (1992)
    Springer
    Applied physics 54 (1992), S. 293-299 
    Details
    ISSN: 1432-0630
    Keywords: 68.55 ; 73.60F ; 78.65J ; 81.15E
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Stoichiometric polycrystalline In2Se3 thin films have been grown by elemental evaporation on both glass and quartz substrates. The compositions are examined by DAN fluorimetry and X-ray photoelectron spectroscopy (XPS). Structure of the films are characterized by X-ray diffraction. The structure of this α-form of thin films have been determined to be hexagonal. Optimization of the preparative conditions employed for elemental evaporation, helped in preparing monophasic films by the suppression of other phases to a very minor extent. Influence of annealing conditions on the stoichiometry of the films are investigated in detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323853
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  • 19
    Electronic Resource
    Electronic Resource
    The gregarisation pheromone of locusts (1970)
    Springer
    Chromosoma 29 (1970), S. 462-473 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Swarming locusts show three physical criteria, i.e. the phase changes of melanisation of the nymphal stages or hoppers, of the proportions of certain body parts (morphometric ratios), and increased genetic recombination (meiotic chiasma frequencies) in the adult. The control of these changes, initiated by aggregation into swarms, i.e. gregarisation, seems to be vested in a pheromone which is produced by all hoppers in both the solitaria and gregaria phases, also by hoppers of the albino strain. Such a pheromone can be extracted from the locust room air and from the locust, these extracts showing high activity in bioassays, primarily in increased chiasma frequencies but also in hopper colour. The extract in risella oil is more efficient than that in petroleum ether and can be distilled to yield an active distillate. The pheromone is secreted in the faeces of hoppers but not of adults. There is evidence in faeces bioassays that all three physical criteria are affected; the pheromone may be called locustone. It is manufactured or secreted in a specific section of the alimentary canal, i.e. the crop. Reception is not through the antennae but through the stigmata. Preliminary chemical analysis of a risella oil air extract distilled into various other solvents showed the presence of a relatively simple saturated aliphatic chain with a carbonyl function, perhaps a ketone or an ester.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00281928
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  • 20
    Electronic Resource
    Electronic Resource
    Focusing biodiversity research on the needs of decision makers (1996)
    Springer
    Environmental management 20 (1996), S. 865-872 
    Details
    ISSN: 1432-1009
    Keywords: Biodiversity ; Ecosystem management ; Ecological stewardship ; Sustainable development ; Assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The project on Biodiversity Uncertainties and Research Needs (BURN) ensures the advancement of usable knowledge on biodiversity by obtaining input from decision makers on their priority information needs about biodiversity and then using this input to engage leading scientists in designing policy-relevant research. Decision makers articulated concerns related to four issues: significance of biodiversity; status and trends of biodiversity; management for biodiversity; and the linkage of social, cultural, economic, legal, and biological objectives. Leading natural and social scientists then identified the research required to address the decision makers' needs and determined the probability of success. The diverse group of experts reached consensus on several fundamental issues, helping to clarify the role of biodiversity in land and resource management. The BURN participants identified several features that should be incorporated into policy-relevant research plans and management strategies for biodiversity. Research and assessment efforts should be: multidisciplinary and integrative, participatory with stakeholder involvement, hierarchical (multiple scales), and problem- and region-specific. The activities should be focused regionally within a global perspective. Meta-analysis of existing data is needed on all fronts to assess the state of the science. More specifically, the scientists recommended six priority research areas that should be pursued to address the information needs articulated by decision makers: (1) characterization of biodiversity, (2) environmental valuation, (3) management for sustainability—for humans and the environment (adaptive management), (4) information management strategies, (5) governance and stewardship issues, and (6) communication and outreach. Broad recommendations were developed for each research area to provide direction for research planning and resource management strategies. The results will directly benefit those groups that require biodiversity research to address their needs—whether to develop policy, manage natural resources, or make other decisions affecting biodiversity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205966
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