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  • Polymer and Materials Science  (239)
  • Cell & Developmental Biology  (71)
  • SOLAR PHYSICS
  • 1980-1984  (350)
  • 1960-1964
  • 1935-1939
  • 1982  (350)
Collection
Publisher
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  • 1980-1984  (350)
  • 1960-1964
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 16 (1982), S. 381-398 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Numerous hypotheses exist to explain observed blood-materials interactions. It is the purpose of this article to test two popular hypotheses, namely, the minimum interfacial free energy hypothesis and the optimum polar/apolar ratio hypothesis. Methacrylate polymers and copolymers were characterized using the captive bubble underwater contact angle method; bulk water content was determined by gravimetric methods; streaming potential measurements were made; and surface roughness and possible particulate contamination were evaluated by reflected light microscopy. In vitro blood tests include whole blood clotting time measurements on polymer-coated tubes; centrifugal force platelet adhesion on polymer-coated coverslips; and a measure of the partial thromboplastin time, Russell's viper venom time (Stypven time), and the prothrombin time of native whole blood exposed to polymer-coated microscope slides. Results suggest that platelet adhesion correlates in the opposite direction of whole blood clotting time and partial thromboplastin time, emphasizing the need for a multiparameter approach to blood-materials testing. Based on these tests the minimum interfacial free energy hypothesis is not supported. In fact, the data suggest the opposite to be true. It is apparent that platelet adhesion can be a misleading indicator of blood compatibility. Neither hypotheses can explain the apparent conflict between the platelet adhesion data and the coagulation time data.
    Additional Material: 9 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 112 (1982), S. 10-18 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Intermediate subviral particles (ISVP) derived from reovirus represent a simple model system for the switch-on of transcriptase function. In such particles the endogenous transcriptase is present in a switched-off form, one step removed from the switched-on state. Switch-on of transcriptase function is an active process in this system and can be triggered by K+ ions. A variety of agents which affect gene expression in cells were tested for an effect on switch-on in ISVP. Marked effects on switch-on in ISVP were observed with a diverse group of test agents, including DMSO and other solvents, BUdR, TdR, caffeine, theophylline, and temperature. The correlation in response between ISVP and cells suggests that the ISVP system may be useful as a model for studying the biochemical mechanisms underlying the perturbative effects of such agents on gene expression in cells.
    Additional Material: 14 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 21 (1982), S. 2265-2277 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Human fibrinogen was treated with thrombin in the presence of fibrinoligase (Factor XIIIa) and calcium ion at pH 8.5, ionic strength 0.45, and the ensuing polymerization was interrupted at various time intervals (t) both before and after the clotting time (tc) by solubilization with a solution of sodium dodecylsulfate and urea. Aliquots of the solubilized protein were subjected to gel electrophoresis on polyacrylamide gels after disulfide reduction by dithiothreitol and on agarose gels without reduction. The degree of γ-γ ligation was determined from the former and the size distribution of ligated oligomers, for degree of polymerization x from 1 to 10, from the latter. In some experiments, thrombin was inhibited, after partial polymerization, by p-nitrophenyl-p′-guanidinobenzoate. From these, it was concluded that for thrombin concentration ≤0.013 units/mL and fibrinoligase ≥30 mg/L, oligomer assembly is rapid compared with peptide A release and ligation is rapid compared with assembly. Under these conditions, the theory of the first paper of this series describes rather well the time dependences of the degree of γ-γ ligation, the weight fractions of monomer and small oligomers, and the number- and weight-average degrees of polymerization after solubilization of the staggered overlapped assemblies, each of which splits to give two strands of end-to-end ligated oligomers. The theory assumes that the second A peptide is released by thrombin more rapidly than the first by a factor q, which, from the experimental data, is determined to be 16. The subsequent assembly into staggered overlapped oligomers follows the statistics of linear polycondesation taking into account the presence of both difunctional and monofunctional combining units. For higher thrombin or lower fibrinoligase concentrations, ligation fails to keep pace with oligomer assembly, and the size distributions after solubilization show a higher proportion of very small and a lower proportion of larger ligated oligomers, owing to separation of the staggered overlapped assemblies into smaller fragments.
    Additional Material: 10 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 43-72 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A scanning electron microscopy study was made of the male setiferous sex patches and analogous structures in 11 families of Coleoptera (Anthribidae, Bruchidae, Ciidae, Cleridae, Coccinellidae, Dermestidae, Leiodidae, Ptinidae, Staphylinidae, Tenebrionidae, and Ostomatidae). These secondary sexual characters appear to have several features in common including relatively long, often ridged, setae, cuticular ducts (frequently cribriform pore plates), and the production of a secretion. It is suggested that these structures may all be concerned with the production, release, and dissemination of pheromones.
    Additional Material: 21 Ill.
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  • 5
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ovaries of the beetle Xyleborus ferrugineus reared on standard sawdust diet with an without 0.08% sorbic acid added were examined for differences in ultrastructural development of the oocytes. Indications of vigorous yolk deposition are an extensive rough-surfaced endoplasmic reticulum (RER), numerous electron-dense secretory vesicles and a prominent nucleus in associated follice cells, and extremely electron-opaque material in the interfollicular cell spaces and the perioocytic area. After 6 days of feeding without added sorbic acid, a mature terminal oocyte is present in one of the two ovaries. This terminal oocyte at this mature stage contains yolk spheres and lipid bodies. However, the most mature oocyte in beetles reared on the standard sawdust diet to which 0.08% sorbic acid was added remained at a previtellogenic stage after 6 days of feeding. Titers of ecdysone in 6-day-old adult females reared on standard sawdust without and with 0.08% sorbic acid added were 534.64 ± 20.93 S.D. pg/mg and 39.94 ± 14.71 S.D. pg/mg body weight, respectively.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 123-138 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The late embryonic and postembryonic genesis of the bursa cloacae (Fabricii) of struthioniforms and other birds is described and discussed. The bursa of ostrich and emu is a wall organ of the caudal cloacal chamber. The bursa of rhea is, like the bursa of Gallus, a cranial appendix of the proctodeum. Lobuli bursales of struthioniforms are composed of a peripheral pars lymphoepithelialis (PLE) and a central pars lymphoreticularis (PLR). By contrast, lobuli bursales of Gallus are composed of a peripheral PLR and a central PLE. The fine structure of the bursa of struthioniforms is described. Other than in Gallus, the apical cell association of the PLE of struthioniforms shows secretory granules. This study thus far does not answer in detail the question of how the imprinting mechanism of the B-lymphocytes operates. It is assumed that they are imprinted in the PLE. Postcapillary venules in the PLR are responsible for the transport of B-lymphocytes. Hormonal bursectomies have been made to get information about the involution of the bursa of struthioniforms. In these species, involution means a gradual metaplasia while in Gallus it means a complete degeneration of the bursa.
    Additional Material: 16 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 3591-3595 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Oligomers are potentially useful as well characterized models for studying the chemical and physical properties of their long chain homologues. These model compounds are often available only as mixtures which must be separated. This separation may be accomplished using chromatographic techniques, i.e., GPC. Polydispersity (Mw/Mn) is often used as a criteria for the extent to which separation has been achieved. Values of polydispersity of 1.01-1.03 are considered indicative of very narrow fractions in the high polymer area. A purpose of this paper is to show that such low values of polydispersity are misleading when applied to oligomers containing 2-20 repeat units. Further, the existence of a single “sharp” melting endotherm is not necessarily proof that one has separated out a single molecular weight component. An intimate mixture of different molecular weight oligomers can give a single narrow endotherm.
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 113-119 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 33 (1982), S. 155-163 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Triphenylmethanfarben als Korrosionsinhibitoren für Aluminium-Kupfer-Legierungen in SalzsäureDie Inhibierung der Korrosion von Aluminium B 26 S in Salzsäure durch Triphenylmethan-, Anthrachinon- und Acridinfarben wurde unter Berücksichtigung von Säurekonzentration, Inhibitordosierung, Versuchsdauer und Temperatur untersucht. Im allgemeinen nimmt bei konstanter Säurekonzentration der Hemmwert von Malachitgrün, Methylviolett 6 B and „light green“ mit der Inhibitorkonzentration zu, während der von Fuchsinbase und Kristallviolett mit zunchmender lnhibitorkonzcntration geringer wird. Bei konstanter Inhibitorkonzentration nimmt andererseits die Wirksamkeit aller untersuchten Verbindungen (mit Ausnahme von Methylviolett 6 B und Acridinorange) mit steigender Säurekonzentration zu. Der Hemmwert aller untersuchten Verbindungen steigt im Temperaturbereich 20-50°C mit der Temperatur, während kein Einfluß der Versuchsdauer zu erkennen ist. Bei einer lnhibitorkonzentration von 0,1% in 0,5 M Salzsäure nimmt der Hemmwert in der folgenden Reihe zu: Fuchsinsäure (32%) 〈 Acridinorange 〈 Fuchsinbase (39%) 〈 Alizarinrot S (46%) 〈 Methylviolett 6 B (50%) 〈 Malachitgrun (64%) 〈 Kristallviolett (70%) 〈 „light green“ (80%).Die Wirkung der Inhibitoren scheint durch Absorption nach einer Langmuir-Adsorptionsisotherme bedingt zu sein. Das wird durch die Korrosionspotentiale bestätigt; allerdings dürfte bei galvanostatischer Polarisation die Kathode bevorzugt polarisiert werden.
    Notes: The inhibition of the corrosion of B 26 S aluminium in HCl solutions by triphenylmethane, anthraquinoid and acridine dyes has been studied in relation to the concentration of acid and inhibitor, duration of immersion and temperature. In general, at constant acid concentration, the inhibiting efficiency of malachite green, methyl violet 6 B and light green increases, whereas that of fuchsine base and crystal violet decreases as the inhibitor concentration increases. At constant inhibitor concentration the efficiency of all the compounds except methyl violet 6 B and acridine orange increases with increasing acid concentration. The inhibitive efficiency of all the compounds increases with temperature in the range 20-50°C, but no dependence can be recognized on the duration of immersion. At an inhibitor concentration of 0.1% in 0.5 M HCl the efficiency increases in the order: fuchsine acid (32%) 〈 acridine orange ≤ fuchsine base (39%) 〈 alizarin red S (46%) 〈 methyl violet 6 B (50%) 〈 malachite green (64%) 〈 crystal violet (70%) 〈 light green (80%).The inhibitors appear to function through adsorption following the Langmuir adsorption isotherm. From the corrosion potentials the inhibitors appear to function through general adsorption but under galvanostatic polarisation conditions, the cathode appears to be preferentially polarised.
    Additional Material: 9 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 105 (1982), S. 83-90 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: 2-Hydroxypropylmethacrylat wurde mit Ethylacrylat und n-Butylacrylat in Masse bei Temperaturen zwischen 60 und 100°C copolymerisiert unter Verwendung von Benzoylperoxid als Initiator. Die Zusammensetzung der Copolymeren wurde durch Hydroxylgruppenbestimmung analysiert; die Copolymerisationsparameter wurden nach der Kelen-Tüdös-Methode berechnet. Die Arrheniusparameter wurden abgeleitet, und die Grenzviskositäten und das thermische Verhalten der Copolymeren wurden ebenfalls untersucht.
    Notes: 2-Hydroxypropyl methacrylate has been copolymerized with ethyl acrylate and n-butyl acrylate in bulk at temperatures between 60 and 100°C using benzoyl peroxide as initiator. The compositions of copolymers have been analyzed by hydroxyl determination; the reactivity ratios have been calculated by Kelen-Tüdös method. Arrhenius parameters have been derived. The intrinsic viscosities and the thermal behaviours of the copolymers were also studied.
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