Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 3847-3849 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The current gain cutoff frequency of very high frequency AlGaAs/GaAs heterojunction bipolar transistors has been measured at 300 and at 20 K using the picosecond optoelectronic technique. These devices showed cutoff frequencies of 72 and 84 GHz at room temperature and at a fixture temperature of 20 K, respectively. Optical response measurements were also obtained at visible and infrared wavelengths. The visible optical response shows a FWHM of 14 and 9.5 ps at 300 and 20 K, respectively. The infrared (λ=850 nm) optical response, corresponding to deeper penetration, showed a FWHM significantly larger ((approximately-greater-than)50 ps) than the visible optical response.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 283 (1980), S. 485-486 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Extensor digitorum longus muscles from male Wistar rats were mounted in a muscle bath and perfused with oxygenated Ringer's solution. The temperature of the bath was regulated by water circulating around its jacket. Intracellular recordings were made with microelectrodes filled with 3M KC1. The ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Computers and Education 15 (1990), S. 105-110 
    ISSN: 0360-1315
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Pädagogik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 294 (1981), S. 582-584 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The recording arrangements in these experiments were similar to those reported previously5. Using male guinea pigs (300-400 g), intracellular recordings were made with glass micropipettes filled with 3 M KC1. All recordings were made at the distal end of the cardiac PV and the dorsal surface of the ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Samples of males reveal the presence of a large, mitotically stable supernumerary chromosome in five populations examined. A stable frequency (11.22±0.3%) of male carriers has been observed over nine years in one population. The supernumerary follows closely the condensation cycle and behaviour of the sex chromosome in spermatogonial mitosis and meiosis. A structure simulating a terminalized chiasma frequently joins the precocious sex and supernumerary chromosomes during meiotic prophase; these two chromosomes move preferentially (70%) to opposite poles during the subsequent stages producing a differential transmission of the supernumerary to the two sexes. It is possible that the stable frequency in the population is maintained by a conserved balance between the two sexes without the need of an elimination system. The evidence supports the interpretation that the supernumerary chromosome is partially homologous with the sex chromosome. The possibility that the supernumerary might evolve into a neo-Y chromosome is suggested.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 400 (1984), S. 335-337 
    ISSN: 1432-2013
    Schlagwort(e): vascular smooth muscle ; excitatory junction potential ; excitation-contraction coupling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Stimulation of the perivascular nerves elicited two types of electrical responses in the rat tail artery—excitatory junction potentials (e.j.p.s) and slow depolarization—and two types of mechanical responses—fast and slow contractions. Fast phasic contractions were triggered whenever action potentials were generated from either the e.j.p. or the slow depolarization reaching threshold. Slow tonic contractions and slow depolarizations were sensitive to α-adrenergic blockade. However the slow contraction always preceded the slow depolarization. Bolus doses of exogenous noradrenaline also induced slow contraction and slow depolarization and the development of tension also preceded the membrane potential change. Increasing the external KCl also induced membrane depolarization however, contractions were not observed until the membrane was depolarized positive of −49 mV. In contrast, tension developed readily with membrane potential more negative than −49 mV with exogenous noradrenaline and neural stimulation, suggesting that the action of noradrenaline was not mediated by electromechanical coupling. It was concluded that vascular activity in the rat tail artery could be regulated by the e.j.p., the slow depolarization and also by pharmacomechanical coupling.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 57 (1967), S. 232-238 
    ISSN: 1432-072X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Gegen den Pilz Trametes versicolor (Isolierung D4) wurde ein Antiserum entwickelt. Die Untersuchungen wurden mit der Agar-gel-Doppelt-diffusionsmethode ausgeführt und zeigten zum mindesten acht antigenische Komponenten in den Pilzen. Einige Antigene, die identisch zu denen in D4 sind, wurden in den anderen verwandten Pilzen entdeckt. Es wurden die beiden Arten des antiserums geprüft: das absorbierende und das nichtabsorbierende. Im ganzen scheinen sich die serologischen Daten mit der konventionellen Klassifizierung zu decken und so wird vorgeschlagen, daß man die serologische Methode gut zur Identifizierung verschiedener Trametes-Gattungen anwenden könnte.
    Notizen: Summary An antiserum against Trametes versicolor isolate D4 has been developed. The use of agar-gel double-diffusion tests has revealed at least eight antigenic components in the fungus. Some antigens identical to those of D4 have been detected in other related fungi using both unabsorbed and absorbed antiserum. The overall serological data seem to agree with the conventional classification of these fungi and it is suggested that serological methods may be useful in identifying various Trametes species.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 425 (1993), S. 482-490 
    ISSN: 1432-2013
    Schlagwort(e): Membrane rectification ; Potassium channels ; Vascular smooth muscle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Membrane rectification to depolarization was studied by voltage recording with patch electrodes in freshly isolated cells from the rat tail artery. Injection of depolarizing currents elicited electrotonic potentials that developed with a single-exponential time course (time constant of 94.8 ms). When the cell was depolarized beyond −30 mV, delayed rectification was observed. A second type of rectification, characterized by oscillations, was observed when the cell was depolarized positive to + 30 mV. The threshold of this rectification and the oscillations were sensitive to changes in intracellular Ca2+. Delayed rectification was more sensitive to 4-aminopyridine but more resistant to tetraethylammonium and charybdotoxin than the Ca2+-sensitive rectification. A 4-aminopyridine-sensitive outward current (I K,dr) with a threshold of around −30 mV and a second Ca2+-sensitive outward current (I K,Ca) activated at around + 30 mV were observed from whole-cell voltage clamp recordings. I K,Ca was blocked by tetraethylammonium and charybdotoxin. An 11-pS and a 122-pS channel, having characteristics similar to I K,dr and I K,Ca respectively, were identified from single-channel recordings. These observations showed how membrane depolarization of vascular smooth-muscle cells was regulated by these two populations of K+ channels under various conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 21 (1987), S. 741-771 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Glutaraldehyde crosslinking of native or reconstituted collagen fibrils and tissues rich in collagen significantly reduces biodegradation. Other aldehydes are less efficient than glutaraldehyde in generating chemically, biologically, and thermally stable crosslinks. Tissues crosslinked with glutaraldehyde retain many of the viscoelastic properties of the native collagen fibrillar network which render them suitable for bioprostheses. Implants of collagenous materials crosslinked with glutaraldehyde are subject long-term to calcification, biodegradation, and low-grade immune reactions. We have attempted to overcome these problems by enhancing crosslinking through (a) bridging of activated carboxyl groups with diamines and (b) using glutaraldehyde to crosslink the ∊-NH2 groups in collagen and the unreacted amines introduced by aliphatic diamines. This crosslinking reduces tissue degradation and nearly eliminates humoral antibody induction. Covalent binding of diphosphonates, specifically 3-amino-1-hydroxypropane-1, 1-diphosphonic acid (3-APD), and chondroitin sulfate to collagen or to the crosslink-enhanced collagen network reduces its potential for calcification. Platelet aggregation is also reduced by glutaraldehyde crosslinking and nearly eliminated by the covalent binding of chondroitin sulfate to collagen. The cytotoxicity of residual glutaraldehyde - leaching through the interstices of the collagen fibrils or the tissue matrix - and of reactive aldehydes associated with the bound polymeric glutaraldehyde can be minimized by neutralization and thorough rinsing after crosslinking and storage in a nontoxic bacteriostatic solution.
    Zusätzliches Material: 22 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...