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  • 1
    Electronic Resource
    Electronic Resource
    Ein Modell zur stufenweisen Umsetzung von Software-Wiederverwendung in der Praxis (1995)
    Springer
    Informatik, Forschung und Entwicklung 10 (1995), S. 197-213 
    Details
    ISSN: 0949-2925
    Keywords: Schlüsselwörter: Software-Wiederverwendung ; Wartbarkeit ; Standards ; Qualitätssicherung ; Managementaspekte ; Einführung von Wiederverwendung ; CR Subject Classification: D.2.7 ; D.2.9 ; D.2.m
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Abstract. Reuse of existing software can significantly increase productivity and provide higher maintainability as well as higher product quality. Existing software systems in industrial practice are usually very heterogeneous – even within the same company. The software varies in age, problem domain, level of documentation, used development environments as well as in levels of software engineering consciousness and skills among the involved software developers and maintainers. We describe a model for reuse that provides three levels of reuse intensities/investments designed to lead from basic maintainability to a company-wide reuse culture. The model is based on suggestions in state-of-the-art reuse research and our experiences in two consulting projects with in-house-developers in the banking and insurance industry to meet local constraints of time and costs. Important roles of personnel and accompanying organizational measures are explained. Successful introduction of institutionalized reuse needs a shaping of the corporate culture, which must be oriented towards enhancing the potential of employees rather than toward trying out the hottest ideas of method-consultants or tool-vendors.
    Abstract: Key words: software reuse, maintainability, standards, quality assurance, management issues, introduction of reuse
    Notes: Zusammenfassung. Die Wiederverwendung bereits existierender Software verspricht sowohl höhere Produktivität als auch bessere Wartbarkeit und Produktqualität. In der industriellen und wirtschaftlichen Praxis anzutreffende Software ist allerdings schon innerhalb eines Unternehmens sehr heterogen. Sie variiert stark in Alter, Anwendungsgebiet, Dokumentationsgrad, verwendeter Entwicklungsumgebung und ist durch Programmierer mit unterschiedlichem Ausbildungsstand im Software-Engineering entstanden. Für die Einführung von Software-Wiederverwendung (Reuse) in der Praxis schlagen wir drei Entwicklungsstufen vor, die durch schrittweise steigende Investitionen von der Basis grundsätzlicher Wartbarkeit bis zu einer unternehmensweiten Reuse-Kultur führen. Das Modell baut auf Vorschlägen der Reuse-Forschung und unseren Erfahrungen mit zwei Beratungsprojekten aus der Praxis industrieller Software-Entwicklung im Bank- und Versicherungsbereich mit Rücksicht auf lokale Zeit- und Kostenbeschränkungen auf. Die für den Einsatz von Software-Wiederverwendung notwendigen Rollen der beteiligten Mitarbeiter und begleitende organisatorische Maßnahmen werden erklärt. Die erfolgreiche institutionalisierte Einführung von Wiederverwendung bedingt eine Anpassung der Unternehmenskultur, deren Verlauf sich mehr am Potential der vorhandenen Mitarbeiter orientieren muß als am Einsatz der neuesten Ideen von Methoden- oder Werkzeuganbietern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004500050027
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  • 2
    Electronic Resource
    Electronic Resource
    Chemotherapeutic Drugs Released from Polymers: Distribution of 1,3-bis(2-chloroethyl)-l-nitrosourea in the Rat Brain (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 671-682 
    Details
    ISSN: 1573-904X
    Keywords: controlled release ; brain tumor ; polymer ; diffusion ; BCNU
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The distribution of [3H]BCNU following release from polymer implants in the rat brain was measured and evaluated by using mathematical models. Methods. [3H]BCNU was loaded into p(CPP:SA) pellets, which were subsequently implanted intracerebrally in rats; [3H]BCNU was also directly injected into the brains of normal rats and rats with intracranially transplanted 9L gliomas. Concentrations of [3H]BCNU on coronal sections of the brain were measured by autoradiography and image processing. For comparison, the kinetics of [3H]BCNU release from the p(CPP:SA) polymer discs into phosphate-buffered saline were also measured. Results. High concentrations of BCNU (corresponding to ~1 mM) were measured near the polymer for the entire 30-day experiment. The penetration distance, defined as the distance from the polymer surface to the point where the concentration of [3H]BCNU in the tissue had dropped to 10% of the maximum value, was determined: penetration distance was ~5 mm at day 1 and ~1 mm at days 3 through 14. Local concentration profiles were compared with a mathematical model for estimation of the modulus φ2, an indicator of the relative rate of elimination to diffusion in the brain. From day 3 to 14, φ2 was ~7, indicating that BCNU elimination was rapid compared to the rate of diffusive penetration into tissue. The enhanced penetration observed on day 1 appears to be due to convection of extracellular fluid caused by transient, vasogenic edema, which disappears by day 3. Conclusions. Polymer implants produce very high levels of BCNU in the brain, but BCNU penetration into brain tissue is limited due to rapid elimination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016083113123
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  • 3
    Electronic Resource
    Electronic Resource
    Morphological Characterization of Polyanhydride Biodegradable Implant Gliadel® During in Vitro and in Vivo Erosion Using Scanning Electron Microscopy (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 683-691 
    Details
    ISSN: 1573-904X
    Keywords: controlled release ; polyanhydride ; biodegradable polymer ; brain rumor ; GLIADEL® implant ; scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The objectives of the current study are to characterize the distribution of the chemotherapeutic agent carmustine (BCNU) in spray dried polyanhydride microspheres and to describe the morphological changes that occur during the in vitro and in vivo erosion of the polyanhydride implant-GLIADEL®, which consists of BCNU distributed in the copolymer matrix of poly(carboxyphenoxy propane:sebacic acid) in a 20:80 molar ratio (p(CPP:SA, 20:80)). Methods. Scanning electron microscopy (SEM) was used to visualize the morphological changes of the polymer during the manufacturing process and in vitro and in vivo erosion. Results. This study revealed that BCNU was homogeneously distributed within spray dried polyanhydride microspheres with no phase separation. The porosity of the wafer fabricated from spray dried polyanhydride microspheres gradually increased during erosion. During the initial period following wafer implantation in the brains of rats, erosion was mainly confined to the surface layer of the wafer with the majority of the wafer remaining intact. The eroding front gradually advanced from the surface to the interior of the wafer in a layerwise fashion, creating pores and connecting channel. Eventually both the interior and exterior of the wafers were eroded and the same porous structure was seen throughout the whole wafer. Conclusions. This study provides the first visual observation of the morphological changes of the GLIADEL® wafer during erosion of the polyanhydride matrix and release of the drug substance BCNU. The observations in this study support the conclusion that BCNU release from a polyanhydride wafer is controlled both by diffusion of the drug and erosion of the polymer matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016035229961
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  • 4
    Electronic Resource
    Electronic Resource
    Mutations in the chloride channel gene, CLCNKB , cause Bartter's syndrome type III (1997)
    [s.l.] : Nature Publishing Group
    Nature genetics 17 (1997), S. 171-178 
    Details
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Analysis of patients with inherited hypokalaemic alkalosis resulting from salt–wasting has proved fertile ground for identification of essential elements of renal salt homeostasis and blood–pressure regulation. We now demonstrate linkage of this phenotype to a segment of chromosome 1 ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/ng1097-171
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of the gene for β-fructosidase (invertase, inulinase) of the hyperthermophilic bacterium Thermotoga maritima, and characterisation of the enzyme expressed in Escherichia coli (1998)
    Springer
    Applied microbiology and biotechnology 50 (1998), S. 55-64 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This is the first report describing the gene structure and the enzymatic properties of a β-fructosidase of a hyperthermophilic organism. The bfrA gene of the ancestral bacterium Thermotoga maritima MSB8 codes for a 432-residue, polypeptide of about 50 kDa, with significant sequence similarity to other β-fructosidases. On the basis of its primary structure, BfrA can be assigned to glycosyl hydrolase family 32. The bfrA gene was expressed in Escherichia coli and the recombinant enzyme was purified and characterised. BfrA was specific for the fructose moiety and the β-anomeric configuration of the glycosidic linkages of its substrates. The enzyme released fructose from sucrose and raffinose, and the fructose polymer inulin was hydrolysed quantitatively in an exo-type fashion. BfrA displayed similar catalytic efficiencies for the hydrolysis of sucrose and inulin with k cat/K m values (at 75 °C, pH 5.5) of about 4.1 × 104 M−1s−1 and 3.1 × 104 M−1s−1 respectively. BfrA had an optimum temperature of 90–95 °C (10-min assay) and was extremely insensitive to thermo-inactivation. During 5 h at temperatures up to 80 °C at pH 7, the enzyme retained at least 85% of its initial activity. Thus, BfrA is the most thermostable β-fructosidase and also the most thermostable inulinase described to date. In conclusion, the T. maritima enzyme can be classified as an exo-β-d-fructofuranosidase (EC 3.2.1.26) with invertase and inulinase activity. Its catalytic properties along with the extreme thermostability recommend it for use in biotechnology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530051256
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  • 6
    Electronic Resource
    Electronic Resource
    Expression of the murine wild-type tyrosinase gene in transgenic rabbits (1996)
    Springer
    Transgenic research 5 (1996), S. 405-411 
    Details
    ISSN: 1573-9368
    Keywords: breeding control ; colour marker ; gene transfer ; pigmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The tyrosinase gene is known to be essential for melanization and has been shown to rescue pigmentation in albino mice. Previously we have described the strict copy-number-dependent expression of a murine wild-type tyrosinase gene construct over several generations in transgenic mice. In this study, we analysed the same gene construct as a marker gene for the transmission and expression of transgenes in rabbits. Using an albino hybrid strain, we produced transgenic rabbits expressing the murine tyrosinase gene. Strict correlation between integration and expression of the transgene and stable germline transmission of the integrated gene construct according to the Mendelian pattern of inheritance was observed. Thus, breeding control was facilitated by simple phenotypic examination of the transgenic animals. In contrast to mice transgenic for the same gene construct, tyrosinase-transgenic rabbits showed a greater variety in hue, intensity and extent of coat pigmentation, which is caused by the diversity in the loci affecting the melanization. Benefits and limitations of tyrosinase as a marker gene for the detection of homozygous individuals in the albino hybrid strain used are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01980205
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  • 7
    Electronic Resource
    Electronic Resource
    Stable Production of Human Insulin-like Growth Factor 1 (IGF-1) in the Milk of Hemi- and Homozygous Transgenic Rabbits Over Several Generations (1998)
    Springer
    Transgenic research 7 (1998), S. 437-447 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008831028620
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  • 8
    Electronic Resource
    Electronic Resource
    Stable Long Term Germ-Line Transmission of Transgene Integration Sites in Mice (1999)
    Springer
    Transgenic research 8 (1999), S. 1-8 
    Details
    ISSN: 1573-9368
    Keywords: gene construct ; gene transfer ; heritability ; marker gene ; pigmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic mice provide a valuable tool in all fields of basic and applied biological and medical research. In this study, we describe the fate of integrated transgenes in the mammalian host genome over a large number of generations. The stability of the germ-line transmission of integrated tyrosinase transgene copies was monitored up to generation F20 in a large number of individuals from seven transgenic mouse lines. Phenotypic and molecular genetic analysis of the offspring both within the different lines and in cross-breeding experiments revealed the high stability of the transgene integration sites in mice. Only very few individuals were affected by a transgene copy loss. These results indicate that, once homozygous transgenic lines are established, breeding programs can be continued to a high number of generations without further stringent molecular genetic analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008824028100
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  • 9
    Electronic Resource
    Electronic Resource
    Actions and interactions of growth hormone and insulin-like growth factor-II: body and organ growth of transgenic mice (1997)
    Springer
    Transgenic research 6 (1997), S. 213-222 
    Details
    ISSN: 1573-9368
    Keywords: transgenic mouse ; GH ; IGF-II ; IGF-I ; body growth ; organgrowth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To characterize long-term actions and interactions of growth hormone (GH) and insulin-like growth factor-II (IGF-II) on postnatal body and organ growth, hemizygous phosphoenolpyruvate carboxykinase (PEPCK)-human IGF-II transgenic mice were crossed with hemizygous PEPCK-bovine GH transgenic mice. The latter are characterized by two-fold increased serum levels of IGF-I and exhibit markedly increased body, skeletal and organ growth. Four different genetic groups were obtained: mice harbouring the IGF-II transgene (I), the bGH transgene (B), or both transgenes (IB), and non- transgenic controls (C). These groups of mice have previously been studied for circulating IGF-I levels (Wolf et al., 1995a), whereas the present study deals with body and organ growth. Growth curves (week 3 to 12) were estimated by regression with linear and quadratic components of age on body weight and exhibited significantly (p 〈 0.001) greater linear coefficients in B and IB than in I and C mice. The linear coefficients of male I and C mice were significantly (p 〈 0.001) greater than those of their female counterparts, whereas this sex-related difference was absent in the bGH transgenic groups. The weights of internal organs as well as the weights of abdominal fat, skin and carcass were recorded from 3.5- to 8- month-old mice. In addition, organ weight-to-body weight-ratios (relative organ weights) were calculated. Except for the weight of abdominal fat, absolute organ weights were as a rule significantly greater in B and IB than in I and C mice. IGF-II overproduction as a tendency increased the weights of kidneys, adrenal glands, pancreas and uterus both in the absence and presence of the bGH transgene. Analysis of relative organ weights demonstrated significant (p 〈 0.05) effects of elevated IGF- II on the relative growth of kidneys (males and females) and adrenal glands (females), confirming our previous report on organ growth of PEPCK-IGF-II transgenic mice. In females, IGF-II and GH overproduction were additive in stimulating the growth of spleen and uterus, providing evidence for tissue-specific postnatal growth promoting effects by IGF-II in the presence of elevated IGF-I
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018494108654
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of donor embryo cell number and cell size on the efficiency of bovine embryo cloning (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 42 (1995), S. 53-57 
    Details
    ISSN: 1040-452X
    Keywords: Nuclear transfer ; Oocyte ; Blastomere number ; Blastomere size ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To establish reliable criteria for the evaluation of nuclear donor embryos, we studied the effect of cell number and cell size of in vitro produced day 6 donor morulae on the rate of blastocyst formation following nuclear transfer to in vitro matured oocytes. In experiment 1, donor embryos were divided into three groups with low (25-34), intermediate (40-55), and high (60-81) blastomere numbers. Transfer of nuclei from day 6 morulae with intermediate and high cell numbers resulted in a significantly higher blastocyst rate (31% and 32%, respectively) than use of nuclei from day 6 morulae with low cell numbers (17%) or nuclei from day 7 morulae with 50-83 blastomeres (19%). This suggests that blastomeres from the developmentally advanced day 6 morulae are more viable than blastomeres from retarded embryos. In experiment 2, we evaluated the effect of blastomere size in day 6 donor morulae with intermediate (40-55) or high (60-81) cell numbers on the efficiency of nuclear transfer. In both classes of embryos, small blastomeres were better nuclear donors than large blastomeres. The rates of development to the blastocyst stage were 28% versus 15% (40-55 cells) and 41% versus 25% (60-81 cells), suggesting that small blastomeres include a higher proportion of totipotent cells than the polarized large blastomeres. Our results demonstrate that blastomere number and size markedly affect the efficiency of nuclear transfer and therefore are useful criteria for evaluating nuclear donor embryos. These parameters are easy to determine and may therefore be helpful to improve the efficiency of cattle cloning. © 1995 wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080420107
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