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  • 1
    Electronic Resource
    Electronic Resource
    Disease resistance in farm animals (1991)
    Springer
    Cellular and molecular life sciences 47 (1991), S. 923-934 
    Details
    ISSN: 1420-9071
    Keywords: Disease resistance ; genetic variations ; Mx system ; breeding techniques ; transgenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Genetic variations in disease resistance of farm animals can be observed at all levels of defence against infectious agents. In most cases susceptibility to infections has polygenic origins. In domestic animals only a few instances of a single genetic locus responsible for disease resistance are known. A well-examined example is the Mx1 gene product of certain mice strains conferring selective resistance to influenza virus infections. Attempts to improve disease resistance by gene transfer of different gene constructs into farm animals include the use of monoclonal antibody gene constructs, transgenes consisting of antisense RNA genes directed against viruses and Mx1 cDNA containing transgenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01929883
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  • 2
    Electronic Resource
    Electronic Resource
    A machine vision system for enhancing the teleoperation of an industrial robot (1994)
    Springer
    Machine vision and applications 7 (1994), S. 187-198 
    Details
    ISSN: 1432-1769
    Keywords: Motion computation ; Tracking ; Self-localization ; Image processing ; Navigation ; Camera calibration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper describes a real-time vision system that enhances the teleoperation of a servicing tool used in the heat exchangers of nuclear power plants. The vision system is used to track the position of the tool as it moves over a sheet of tube ends. A map-based strategy is adopted for the estimation of the position. The system incorporates a novel method for a foreshortening correction that is applied prior to map referencing. A hypothesize and verify scheme locates two image features that correspond to two map features. An efficient scheme for extracting image features is developed to locate these two features (tube-end centers) in the image. Two different types of heat-exchanger tube sheets are accounted for. They are those with tube ends placed in a square grid and those with tube ends placed in a triangular grid. The map-based strategy minimizes the cumulative errors in the estimate of the tool head position. The resulting low-cost system has been tested on synthetic and real data. Performance results are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01211663
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  • 3
    Electronic Resource
    Electronic Resource
    Developmental and tissue-specific expression of the Q5 k gene (1991)
    Springer
    Immunogenetics 34 (1991), S. 28-38 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Expression of the Q5 k gene was examined by northern blot analysis and polymerase chain reaction (PCR) in the AKR mouse and various cell lines, each of the H-2 k haplotype. Our results show that Q5 k mRNA is present during the whole postimplantational development of the AKR embryo/fetus (gestation day 6 to 15). In the juvenile mouse (week 2 to 4) transcription of the Q5 k gene persisted in all organs examined. In contrast, in the adult animal expression of the Q5 k gene was limited to the thymus and uterus of the pregnant mouse. Upon malignant transformation, the amount of Q5 k -specific mRNA increased dramatically in thymus and could also be observed in the spleen of thymoma bearing animals. Expression of the Q5 k gene was also detectable in several transformed mouse cell lines. Mitogen stimulation or treatment with cytokines induced Q5 k expression in primary spleen cell cultures. A possible explanation for the tissue-restricted expression in the adult AKR mouse is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212309
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  • 4
    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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  • 5
    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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  • 6
    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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  • 7
    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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  • 8
    Electronic Resource
    Electronic Resource
    Sensitive detection of human growth hormone mRNA in routinely formalin-fixed, paraffin-embedded transgenic mouse tissues by non-isotopic in situ hybridization (1994)
    Springer
    Histochemistry and cell biology 102 (1994), S. 145-152 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A sensitive technique of non-isotopic in situ hybridization (NISH) is presented, which permits the detection of human growth hormone (hGH) mRNA in routinely formalin-fixed, paraffin-embedded transgenic mouse tissues and human post mortem pituitaries; the latter were used as positive tissue controls in this study. In addition, a double staining procedure combining NISH and immunohistochemistry for the visualization of both hGH and hGH mRNA in the same paraffin section is described. Digoxigenin-labelled antisense hGH RNA was used for NISH of hGH mRNA. The NISH protocol was based upon an established radioactive method. Alkaline phosphatase and horseradish peroxidase-based immunoenzymatic procedures for the detection of digoxigenin-labelled RNA probes using different chromogens [4-nitro blue tetrazolium chloride (NBT), Fast Blue BB, New Fuchsin, and 3,3′-diaminobenzidine tetrahydrochloride (DAB) with or without intensification of the DAB staining] were compared. The proteolytic tissue pretreatment and the detection procedure were found to be the most critical steps for successful visualization of hGH mRNA. After optimization of the permeabilization conditions, hGH mRNA could be visualized in each case studied when alkaline phosphatase/NBT-based detection was employed. The NISH technique presented here, performed either separately or in combination with immunohistochemistry, permits retrospective analyses, of hGH (trans)gene expression in archival, paraffin-embedded specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269018
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  • 9
    Electronic Resource
    Electronic Resource
    The physiological role of malic enzyme in grape ripening (1984)
    Springer
    Planta 160 (1984), S. 444-448 
    Details
    ISSN: 1432-2048
    Keywords: Fruit ripening ; Malic enzyme ; Vitis (fruit ripening)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The high specificity of malic enzyme (ME; EC 1.1.1.40) from grape berries (Vitis vinifera L.) for the naturally occurring l-enantiomer of malic acid, its very selective C4-decarboxylation, and certain allosteric properties, reported previously, favour the conjecture of a regulatory function of ME in fruit malic acid degradation. On the other hand, high ME activity was detected even during the acid-accumulating phase of berry development. Also, the in vitro reversibility of the reaction supports the possibility of malate formation under conditions facilitating carboxylation of pyruvate, notably high CO2/HCO 3 - and NADPH/NADP ratios. However, a very limited incorporation of 14C into malate and the uniform labeling pattern of the dicarboxylic acid after administration of [U-14C] alanine to grape berries before and after the onset of ripening, indicate that the ‘reverse” reaction does not contribute essentially to grape malate synthesis. A regulatory mechanism mediating malic acid remetabolization on the basis of cosubstrate availability, comparable to the control of the hexose monophosphate shunt, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429761
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  • 10
    Electronic Resource
    Electronic Resource
    Efficient generation of chimaeric mice using embryonic stem cells after long-term culture in the presence of ciliary neurotrophic factor (1994)
    Springer
    Transgenic research 3 (1994), S. 152-158 
    Details
    ISSN: 1573-9368
    Keywords: CNTF ; LIF ; ES cells ; differentiation ; proliferation ; chimaera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The aim of our study was to evaluate whether ciliary neurotrophic factor (CNTF) can substitute for leukaemia inhibitory factor (LIF) in maintaining pluripotential embryonic stem (ES) cells in culture. Two subclones of D3 ES cells were used to assess cell proliferation and differentiation in the presence of CNTF, LIF or Buffalo rat liver (BRL) cell-conditioned medium, or in the absence of exogenous differentiation inhibiting factors. ES cells maintained in medium supplemented with CNTF for up to four weeks were injected into blastocysts to investigate theirin vivo pluripotency in terms of chimaera formation. CNTF inhibited ES cell differentiation in a dose-dependent manner. The most effective concentration was 10 ng CNTF per ml of medium. The effects of CNTF on ES cell differentiation and proliferation were comparable to those of LIF at the same concentration. BRL cell-conditioned medium was less effective at preventing ES cell differentiation but induced their proliferation very markedly. Both ES cell clones efficiently formed chimaeras after long-term culture with CNTF as the only differentiation inhibiting agent. The ability of these ES cells to colonize the germ-line is the ultimate proof that CNTF can preserve the pluripotency of ES cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973982
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