Bibliothek

X
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
    A computer and analytic study of the metallic liquid–glass transition (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 2700-2705 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The present work examines two aspects of metallic liquid–glass transitions. First, a computer experiment, consisting of a temperature-quench Monte Carlo calculation for the liquid–glass transition of Ca0.7Mg0.3, is carried out. A comparison with such calculations for monatomic metals indicates that there is a significant difference in the Wendt and Abraham criterion for monatomic metals and metallic alloys. In addition, a comparison with laboratory experiments indicates that the discrepancies between the Wendt–Abraham parameters obtained in these laboratory experiments and in the computer experiments can be ascribed to different cooling rates. Second, an analytic study of the pair distribution function near the transition temperature is presented and reproduces the linear temperature dependence of the Wendt–Abraham parameter. This gives a physical picture for this parameter and indicates that the liquid–glass transition is more likely to be a first-order transition than a second-order one.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.453999
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    A computer and analytic study of the metallic liquid–glass transition. II. Structure and mean square displacements (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 4309-4312 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: A study, using both computational and analytic techniques, of the extent to which the cage concept of liquids applies to the metallic liquid–glass transition is presented. Monte Carlo calculations on a Ca0.7Mg0.3 system yield the angular distribution functions required to determine the cage structure and the atomic motion. The analysis parallels that for normal liquids. The results indicate that the cages are icosahedral, that they exist from the melting temperature down into the glass state, and that the cage concept applies quantitatively to the static properties of metallic binary alloys. Finally, the cage concept itself does not appear to describe fully atomic diffusion in metallic systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.454813
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Antitumor agents-CLI. Bis(helenalinyl)glutarate and bis(isoalantodiol-B)glutarate, potent inhibitors of human DNA topoisomerase II
    Amsterdam : Elsevier
    Bioorganic and Medicinal Chemistry 2 (1994), S. 137-145 
    Details
    ISSN: 0968-0896
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0968-0896(00)82008-8
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Determination of proteins at nanogram levels by their quenching effect on large particle scattering of colloidal silver chloride (2000)
    Springer
    Fresenius' journal of analytical chemistry 366 (2000), S. 863-868 
    Details
    ISSN: 1432-1130
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A novel quantitative method for the determination of proteins in aqueous solutions has been based on the quenching of the resonance scattering light of colloidal silver chloride in the presence of proteins. The detection limits for eight kinds of proteins (BSA, HSA, egg albumin, human γ-IgG,α-chymotrypsin, E. Coli. alpsase, myoglobin, α-casein) were at about 8 ng/mL; the linear ranges of the calibration curves were 10–400 ng/mL ¶under optimal conditions,except for human γ-IgG (20–¶400 ng/mL), myoglobin (10–300 ng/mL), and α-casein (10–300 ng/mL). Three wavelengths (398 nm, 475 nm, 499 nm) were all suitable for the determination and any acidity from pH 3.0 to pH 9.0 could be chosen. A few non-protein substances at high concentration levels interfered with this method, but this problem could simply be overcome by diluting the samples before the assay. Mechanism studies showed that the quenching effect of proteins on the scattering light of colloidal silver chloride was mainly due to the coagulation of AgCl particles retarded by protein. The method was employed for the determination of total protein in human serum with sactifactory results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002160051586
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Application of magdala red as a fluorescence probe in the determination of nucleic acids (2000)
    Springer
    Fresenius' journal of analytical chemistry 366 (2000), S. 303-306 
    Details
    ISSN: 1432-1130
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A fluorescence quenching method was developed for the rapid determination of DNA and RNA using magdala red as fluorescence probe. In weakly acidic ¶medium, the fluorescence of magdala red (λex〉lem = 54055 nm) can be largely quenched by DNA or RNA. The calibration graphs are linear over the range 0.01–¶1.2 μg/mL for both calf thymus DNA (CT DNA) and salmon DNA (SM DNA), and 0.015–1.0 μg/mL for yeast RNA, respectively. The corresponding detection limits are ¶6.0 ng/mL for CT DNA, 7.0 ng/mL for SM DNA and ¶15.0 ng/mL for yeast RNA, respectively. CT DNA could be determined in the presence of 20% (w/w) yeast RNA, and the relative standard deviation of six replicate measurements is 3.18% for 400 ng/mL of CT DNA. Interference from coexisting substances in the determination of DNA was also examined. Real samples were determined with satisfactory results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002160050057
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Tolerance to the reinforcing effects of cocaine in a progressive ratio paradigm (1994)
    Springer
    Psychopharmacology 116 (1994), S. 326-332 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Cocaine ; Progressive-ratio schedule ; Rats ; Self-administration ; Tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This experiment used rats to test whether a regimen of chronic cocaine would produce tolerance to cocaine i.v. self-administration under a progressive ratio (PR) schedule of reinforcement. Under this PR schedule, an increasing number of responses was required to complete the ratio for each subsequent cocaine injection, and failure to complete the required ratio for the next injection within 1 h of the previous cocaine injection terminated the session. The number of injections taken in the session was termed the breaking point and used as the dependent variable. Rats were trained under this schedule until breaking point values were stable, after which cocaine dose-effect data were obtained: the breaking point increased as the dose of cocaine increased. Subsequently, rats were assigned to one of two groups for 7 days of chronic treatment: one group was infused with cocaine (18 mg/kg, given over 20 min once every 8 h) and the other group received 0.9% saline. Following termination of chronic treatment, cocaine dose-effect data were redetermined in both groups. Chronic cocaine treatment significantly decreased breaking point values across the entire dose-effect curve, although the effect was observed in only four of seven subjects. In contrast, chronic saline treatment produced no significant effect on the breaking point measures. Following a further 5 days of recovery from chronic treatment, cocaine dose-effect data were redetermined in both groups; these curves were essentially identical to those obtained before chronic treatments. These data support the hypothesis that tolerance occurs to the reinforcing effects of cocaine, as measured by a decrease in the breaking point, at least for a subset of animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02245336
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Variations in cocaine self-administration by inbred rat strains under a progressive-ratio schedule (1996)
    Springer
    Psychopharmacology 127 (1996), S. 204-212 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Genetic basis of substance abuse ; Inbred strains ; Cocaine ; Self-administration ; Progressive-ratio ; Restriction fragment length polymorphisms ; Rats ; D1 receptor ; D2 receptor ; Dopamine ; SCH 23390 ; Eticlopride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study investigated the influence of genetics on extent of cocaine taking in rats that were self-administering cocaine under a progressive-ratio schedule. Fischer 344, ACI and Brown Norway rats were subjects because previous genetic studies on dopamine receptor loci have indicated that these are genetically divergent strains. All subjects were assessed for acquisition and stability of cocaine self-administration under a progressive-ratio schedule. Subsequently, a dose-effect curve for cocaine self-administration was determined for each strain. Fischer 344 rats maintained a higher average breaking point than did the ACI or Brown Norway strains. In addition, dopamine receptor antagonists differentially reduced the ability of cocaine to serve as a reinforcer across the three strains. The D1-selective dopamine receptor antagonist, SCH 23390, and the D2/D3-selective dopamine receptor antagonist, eticlopride, were significantly more effective in reducing the self-administration of cocaine in Brown Norway rats than for the other two strains. The results of this study demonstrate that genetic differences may play an important role in determining responding under progressive-ratio schedules for cocaine, possibly due to differences in the reinforcing efficacy of cocaine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02246128
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Variations in cocaine self-administration by inbred rat strains under a progressive-ratio schedule (1996)
    Springer
    Psychopharmacology 127 (1996), S. 204-212 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Genetic basis of substance abuse ; Inbred strains ; Cocaine ; Self-administration ; Progressive-ratio ; Restriction fragment length polymorphisms ; Rats ; D1 receptor ; D2 receptor ; Dopamine ; SCH 23390 ; Eticlopride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  This study investigated the influence of genetics on extent of cocaine taking in rats that were self-administering cocaine under a progressive-ratio schedule. Fischer 344, ACI and Brown Norway rats were subjects because previous genetic studies on dopamine receptor loci have indicated that these are genetically divergent strains. All subjects were assessed for acquisition and stability of cocaine self-administration under a progressive-ratio schedule. Subsequently, a dose-effect curve for cocaine self-administration was determined for each strain. Fischer 344 rats maintained a higher average breaking point than did the ACI or Brown Norway strains. In addition, dopamine receptor antagonists differentially reduced the ability of cocaine to serve as a reinforcer across the three strains. The D1-selective dopamine receptor antagonist, SCH 23390, and the D2/D3-selective dopamine receptor antagonist, eticlopride, were significantly more effective in reducing the self-administration of cocaine in Brown Norway rats than for the other two strains. The results of this study demonstrate that genetic differences may play an important role in determining responding under progressive-ratio schedules for cocaine, possibly due to differences in the reinforcing efficacy of cocaine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050078
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Rotating clusters: centrifugal distortion, isomerization, fragmentation (1989)
    Springer
    The European physical journal 12 (1989), S. 177-180 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 82.30.Qt ; 36.40. +d ; 03.20. +i
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The effect of the overall rotation, as characterized by the total angular momentum, on the structure of an Ar13 cluster is studied by using a new technique for separation of the rotational motion from vibrations. No a priori limitation on the degree of nonrigidity of the cluster is imposed. The different structures for different total angular momenta of the cluster are arrived at by a thermal quenching procedure which preserves the overall rotation. It is shown that the centrifugal distortion is anisotropic and it may lead to isomerization transitions and even fragmentation of the cluster.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01426932
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Development of instruments for radionuclide-based diagnostics (1991)
    Springer
    Biomedical engineering 25 (1991), S. 149-151 
    Details
    ISSN: 1573-8256
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558674
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...