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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2817-2818 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A multipassage magnetic spectrometer has been constructed which allows selection of a specific high charge state from the extracted ion pulse of our electron beam ion source (EBIS) and to reinject it in the emptied source, now using the electron beam of meanwhile changed energy as a target of free electrons for the study of ionization, dielectronic recombination (DR), or radiative electron capture (REC). The spectrometer consists of a H-magnet with round pole pieces and 4 identical arrangements of achromatic lenses and mirrors under 90° forming a versatile ion switchyard with the possibility of recirculation. The chromaticity of the recirculating transport system and the dispersion of this spectrometer are adjustable by electric potentials on suitably placed electrostatic deflectors inside of the magnetic field. For the injection of ions from an external ion source into the EBIS and to the beam lines, the mirror potentials are pulsed accordingly.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Scandinavian journal of immunology 56 (2002), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Pairwise assembly of human CD3 chains takes place in the endoplasmic reticulum of T cells. Subsequently, the CD3 heterodimers form complexes with Tiα and Tiß chains forming hexameric TiαβCD3γεδε complexes. Finally, association with the ζ2 homodimer occurs in Golgi apparatus before the fully assembled T-cell receptor is transported to the cell surface. To study the structural properties of the human CD3 chains, we have developed new methods to produce and fold the extracellular domains of CD3γ, CD3δ and CD3ε. Proteins were expressed in Escherichia coli as denatured chains and de novo folded in vitro. CD3γ and CD3ε folded as soluble monomers, whereas CD3δ did not yield any soluble proteins. When folding the chains pairwise, soluble CD3γε and CD3δε heterodimers could be isolated, whereas CD3γδ heterodimers were not produced. Using antibodies as structural probes, we identified two different types of antigenic epitopes that were dependent on heterodimerization. Our data indicate that CD3ε undergoes a conformational change after dimerization with CD3γ or CD3δ. Furthermore, we demonstrated that the CD3γε heterodimer could be purified using immunoaffinity chromatography.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Regulation of T-cell receptor (TCR) cell surface expression levels is probably an important mechanism by which T-cell responsiveness is controlled. Previously, two distinct pathways for TCR downregulation have been described. One is dependent on protein kinase C (PKC) and the leucine-based receptor-sorting motif (l-based motif) of the CD3γ chain but independent of tyrosine kinases, whereas the other is dependent on the tyrosine kinase activation but independent of the PKC and the CD3γl-based motif. In this study, we describe a new pathway for TCR downregulation distinct from both the PKC/CD3γl-based motif-dependent and the tyrosine kinase-dependent pathways. This pathway is dependent on ceramide-induced activation of caspases and correlate with caspase-mediated cleavage of the ζ chain. Thus, a 10–15% downregulation of the TCR was induced following the treatment of the T cells with ceramide for 4 h. A close correlation between TCR downregulation, caspase activation, and cleavage of the ζ chain was found. Furthermore, the caspase inhibitors abolished the cleavage of the ζ chain and TCR downregulation in parallel with the inhibition of the caspase activity.
    Type of Medium: Electronic Resource
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  • 4
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    Unknown
    Oxford : Periodicals Archive Online (PAO)
    Economic Inquiry. 18:3 (1980:July) 461 
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 192 (1961), S. 889-890 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We planned to determine whether acceleration could be detected in the prophase of meiosis in anthers of Tradescantia paludosa, in which the prophase stages investigated (from pachytene and diplotene onwards) are of sufficient duration to do so. The anthers were cultured on a modification of the ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    FEBS Letters 291 (1991), S. 345-349 
    ISSN: 0014-5793
    Keywords: Degradation ; Proteolysis ; Rat liver ; Structure ; Structure/function relationship ; Tyrosine aminotransferase
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Experimental Cell Research 199 (1992), S. 305-313 
    ISSN: 0014-4827
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Nuclear Physics, Section A 246 (1975), S. 187-209 
    ISSN: 0375-9474
    Keywords: Nuclear moments
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimie 70 (1988), S. 673-679 
    ISSN: 0300-9084
    Keywords: ELISA ; N- C-terminal parts ; anti-peptide serum ; enzyme activity ; hepatoma cells ; protein sequencing ; tyrosine aminotransferase
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of wildlife research 31 (1985), S. 22-33 
    ISSN: 1439-0574
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary Contaminant emissions affect inanimate objects, plants, animals and humans. Such emissions can be quantified with specialised measuring equipment — without any particular technical expenditure but, rather, exact both as regards time and area. Plants as biomonitors can integrate the quantity and effect of emissions at the defined site over broader periods of time. Thanks to their mobility animals provide additional possibilities of integration throughout different areas. For the wider utilisation of the advantages of biomonitors, the important thing is to recognise the regressions and correlations between emission rates for particular substances measured from the chemical/physical/technical standpoint in specific areas and periods of time and the concentrations of these substances in defined biological samples for the same areas and periods. On this basis there arise economical possibilities for extensive and revealing collection and review of area pattern and temporal trend of contaminant pollution, for interpolation between measuring stations or extrapolation beyond measuring networks, for early recognition of unknown terrain and, in addition, early warning in relation to humans and/or the used or protected components of ecosystems. Ecologists are required to interpret analyses and interrelations. Biomonitoring and specimen banking seem to be sensible concepts. Comparatively small research expenditure on the biological/ecological side could improve and deepen the existing state of things considerably. Bioindication and biomonitoring cannot, however, dispense with calibration through physical/chemical measurements.
    Abstract: Résumé L'émission de matières toxiques agissent sur les matériaux inanimés, les plantes, les animaux, les hommes. De telles émissions se prêtent à des mesures quantitatives au moyen d' appareils adéquats — sans poser de problèmes techniques majeurs mais avec une portée ponctuelle dans l' espace et dans le temps. Des plantes indicatrices peuvent intégrer des émissions ainsi que leurs effets à un endroit déterminé sur des périodes très longues. Les animaux, en raison de leur mobilité, procurent des possibilités d' intégration complémentaires sur des fractions de l' espace. Pour une utilisation plus large des avantages des bio-indicateurs, il convient de déceler les régressions et corrélations entre les mesures des taux d' émission techno-physico-chimiques, pour des matières déterminées au sein d' échantillons biologiques définis au cours des mêmes périodes et fractions de l'espace. Cette donnée de base fournit des possibilités appréciables en vue d'un contrôle extensif et cependant révélateur de points dispersés dans l'espace ainsi que de l'évolution au cours du temps de la charge que constituent les matières toxiques, en vue d'une interpolation entre les stations de mesure ou de l'extrapolation au-delà du réseau de contrôle, ceci de manière à disposer d'une information prémonitoire pour des zones non connues et, partant, d'une indication précoce intéressant la population ou/et les composants exploités ou protégés des écosystèmes. L'interprétation des résultats d'analyse et de leurs interrelations nécessitent des écologues. Le 〉biomonitoring〈 et le 〉specimen banking〈 apparaissent comme de judicieux concepts. Un investissement scientifique relativement modeste sur le plan éco-biologique pourrait améliorer et approfondir considérablement certaines évaluations. La bio-indication et le biomonitoring ne peuvent cependant pas renoncer à l'étalonnage sur base de mesures physico-chimiques
    Notes: Zusammenfassung Schadstoffimmissionen wirken auf unbelebte Stoffe, auf Pflanzen, Tiere und Menschen. Solche Immissionen lassen sich mit geeigneten Meßgeräten quantifizieren — ohne besonderen technischen Aufwand jedoch nur punktuell, in zeitlicher und räumlicher Hinsicht. Pflanzen als Biomonitoren können Immissionsmenge und -wirkung am definierten Ort über größere Zeitspannen integrieren. Tiere bieten durch ihre Beweglichkeit zusätzliche Integrationsmöglichkeiten über Raumausschnitte. Für die breitere Nutzung der Vorteile von Biomonitoren kommt es darauf an, die Regressionen und Korrelationen zwischen chemisch-physikalisch-technisch gemessenen Immissionsraten für bestimmte Stoffe in Zeit- und Raumausschnitten mit den Konzentrationen dieser Stoffe in definierten biologischen Proben für dieselben Zeit- und Raumausschnitte zu erkennen. Auf dieser Grundlage ergeben sich preiswerte Möglichkeiten zur extensiven und doch aussagekräftigen Erfassung und Überwachung von räumlichem Muster und zeitlichem Trend von Schadstoffbelastungen, zur Interpolation zwischen Meßstationen bzw. Extrapolation über Meßnetze hinaus, für erstes Erkunden von unbekanntem Terrain und darüber hinaus zur Frühwarnung in bezug auf den Menschen und/oder auf die genuzten oder geschützten Komponenten von Ökosystemen. Zur Interpretation von Analysen und Zusammenhängen sind Ökologen nötig. „Biomonitoring“ und „Specimen Banking“ erscheinen als vernünftige Konzepte. Vergleichsweise geringer Forschungsaufwand auf biologisch-ökologischer Seite könnte bestehende Ansätze wesentlich verbessern und vertiefen. Auf die Eichung durch physikalisch-chemische Messungen können jedoch Bioindikation und Biomonitoring nicht verzichten.
    Type of Medium: Electronic Resource
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