Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Effect of molecular elongation on the dipolar free energy (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 3946-3949 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The dipolar contribution to the Helmholtz energy FD has been determined for dipolar two-center Lennard-Jones molecules of increasing elongation at one corresponding state point in the liquid. The calculation is based on the dipole–dipole energy obtained from simulations and subsequent integration according to the λ-coupling technique. It results, that at fixed values of the reduced dipole moment μ*2=μ2/(εσ3) with ε and σ being the Lennard-Jones site–site interaction parameters, the dipolar free energy FD is nearly constant as function of the molecular elongation. Keeping the effective dipole moment μ˜2=μ2(ρp/Tp) constant with Tp and ρp being the critical temperature and density obtained from WCA-type perturbation theory, FD increases somewhat with the elongation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.466141
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Computer simulation study of the Rayleigh and Raman spectra of fluid N2 (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 4993-5001 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Computer simulations of the Rayleigh and Raman spectral time-correlation functions (TCFs) are reported for N2 at 323 K and densities ranging from 0.48 to 2.5 times the critical value. The results are compared with experiment. Particular attention is paid to the density dependence of the spectral intensity due to the correlated permanent polarizability and to the interaction-induced contributions to the polarizability. The partial cancellations that occur between various two-, three-, and four-body terms in the cross and collision induced (CI) parts of the spectral TCFs are evaluated. It is shown that these terms are significant in both the Raman and the Rayleigh spectra, but cancellation greatly reduces their net contribution at all densities studied. The weak but uncancelled TCFs that are associated with orientational correlations of the molecular polarizability anisotropies are shown to be a significant part of the high density Rayleigh TCFs. It is argued that the long-range nature of this TCF means that its simulated values are poorly known.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.466001
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Brownian Motion: A Tool To Determine the Pair Potential between Colloid Particles (1994)
    s.l. : American Chemical Society
    Langmuir 10 (1994), S. 1351-1353 
    Details
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/la00017a007
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Classifying spaces for quantum principal bundles (1992)
    Springer
    Communications in mathematical physics 149 (1992), S. 495-512 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract A construction of a quantum analogue of principal bundles is discussed. Deformations of quantum groups in the sense of Woronowicz allow to relax the condition of local triviality of a principal bundle; the fibres need not be all identical any longer. This leads to deformations of structure group and bundles. There is still a classifying space in the sense that homotopy classes of bundles are classified by homotopy classes of maps from the base space into the classifying space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02096940
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Polymorphism of glutathione conjugation of methyl bromide, ethylene oxide and dichloromethane in human blood: Influence on the induction of sister chromatid exchanges (SCE) in lymphocytes (1993)
    Springer
    Archives of toxicology 67 (1993), S. 173-178 
    Details
    ISSN: 1432-0738
    Keywords: Methyl bromide ; Bromomethane ; Ethylene oxide ; Dichloromethane ; Methylene chloride ; Human erythrocytes ; SCE ; Enzyme polymorphism ; Glutathione-S-transferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A hitherto unknown glutathione-S-transferase in human erythrocytes displays polymorphism: three quarters of the population (“conjugators”) possess, whereas one quarter (“non-conjugators”) lack this specific activity. A standard method for the identification of conjugators and non-conjugators with the use of methyl bromide and gas chromatography (head space technique) is described. Three substrates of the polymorphic enzyme, methyl bromide, ethylene oxide and dichloromethane (methylene chloride), were incubated in vitro with individual whole blood samples of conjugators and non-conjugators. All three substances led to a marked increase of sister chromatid exchanges (SCE) in the lymphocytes of the non-conjugators but not in those of conjugators. A protective effect of the glutathione-S-transferase activity in human erythrocytes for the cytogenetic toxicity of these chemicals in vitro is thus confirmed. Since the enzyme activity is not found in erythrocytes of laboratory animals, species extrapolations for risk assessment of methyl bromide, ethylene oxide and dichloromethane should be reconsidered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973304
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Celiprolol exerts microvascular dilatation by activation of β2-adrenoceptors (1992)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 346 (1992), S. 27-31 
    Details
    ISSN: 1432-1912
    Keywords: Celiprolol ; β2-adrenoceptors ; Mesenteric artery ; Microcirculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to clarify the question whether the β1-selective adrenoceptor antagonist celiprolol possesses vasodilating properties, isolated vascular networks were perfused with increasing concentrations of celiprolol (in a cumulative manner) ranging from 10−8 to 10−4 mol/l. The study was carried out using the isolated mesenteric vascular bed of the guinea pig mesenterium coli. Vascular diameters of four different vascular regions [vessels classified as G1 (585 ± 30 μm), G2 (403 ± 25 μm), G3 (282 ± 27 μm) and G4 (197 ± 13 μm)] were assessed by means of microscopic videoangiometry. Perfusion with celiprolol resulted in concentration dependent vasodilation which was more pronounced in G3 and G4 vessels. In addition, cumulative concentration-response curves were determined from responses obtained in the presence of 10−8, 10−7, 10−6 and 10−4 mol/l ICI 118,551 (a highly selective adrenoceptor antagonist). In the presence of ICI 118,551 at concentrations ≥ 10−6 mol/l, no celiprolol response could be observed. Lower concentrations of ICI 118,551 shifted the celiprolol concentration-response curve to the right in a concentration-dependent manner. Therefore, it is concluded (a) that celiprolol has a vasodilating effect, (b) that this vasodilation is produced by stimulation of β2-adrenoceptors and (c) that the vasodilating effect is more pronounced in smaller than in larger vessels (G3, G4 vs G1, G2).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167566
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Determination of methylated globin and albumin for biomonitoring of exposure to methylating agents using HPLC with precolumn fluorescent derivatization (1994)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 350 (1994), S. 712-715 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new method has been developed for the quantitation of methylated blood proteins in persons exposed to methylating agents. Using different derivatizing agents, 9-fluorenylmethyl chloroformate was the most suitable with regard to both sensitivity and peak separation after subsequent HPLC. After optimization of the chromatographic conditions, two groups who worked with methyl bromide and a control group of non exposed persons were compared with regard to their adduct rates (S-methylcysteine) in the two blood proteins albumin and globin. Albumin and globin were isolated from whole blood samples. After total hydrolysis of the proteins with hydrochloric acid, an amino acid analysis was performed using HPLC with precolumn fluorescent derivatization. This method enabled a quantitation of methylated cysteine in the fmol range. Background levels of S-methylcysteine (15 nmol/g protein) in both albumin and globin were found in non-exposed control persons. Levels were up to 10 fold higher in exposed fumigators working with the methylating agent methyl bromide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323669
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The alpha2-adrenergic receptor system in the hypothalamus of the Pekin duck (1992)
    Springer
    Cell & tissue research 268 (1992), S. 99-107 
    Details
    ISSN: 1432-0878
    Keywords: Alpha2 receptors ; Hypothalamus ; Circumventricular organs ; Clonidine ; G-protein ; Domestic mallard
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present study, we have employed the monoradioiodinated α2-agonist clonidine ([125I]-CLO) to characterize duck hypothalamic α2-adrenoceptors and to localize α2-specific binding sites in the duck brain. To validate the α2-specificity of [125I]-CLO using an enriched duck hypothalamic membrane fraction, a radioreceptor assay was established by altering the membrane protein concentration, time, temperature and ionic milieu of incubation, and in the presence or absence of protease inhibitors. Competitive displacement studies revealed the following sequence of potency to displace [125I]-CLO: yohimbine〉(-)-epinephrine〉clonidine〉 (-)-norepinephrine〉phentolamine〉(-)-phenylephrine〉(-)-isoproterenol〉prazosin. The non-hydrolyzable guanosine 5′-triphosphate analog guanylylimidodiphosphate markedly inhibited [125I]-CLO binding suggestive of G-protein involvement. With regard to the histological distribution, diencephalic structures, such as the habenula and the nucleus reticularis of the thalamus, were densely labeled by [125I]-CLO. In the hypothalamus, α2-adrenoceptors were detected in the antidiuretic hormone-synthesizing nucleus paraventricularis, the nucleus praeopticus medialis, the nucleus anterior medialis hypothalami, the nucleus magnocellularis praeopticus, the nucleus commissurae pallii, the nucleus inferior hypothalami and the regio lateralis hypothalami. Circumventricular organs, such as the plexus choroidei, organum subfornicale, organum paraventriculare and the corpus pineale, were endowed with α2-specific binding sites, as were the cell layers of the tectum opticum. In addition, telencephalic structures revealed high receptor densities. The presence of well characterized α2-specific adrenoceptors in hypothalamic structures of the duck brain including associated telencephalic regions supports physiological investigations with regard to functional α2-adrenergic modulation of antidiuretic hormone release in the duck.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338058
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The FUSCA genes of Arabidopsis: negative regulators of light responses (1994)
    Springer
    Molecular genetics and genomics 244 (1994), S. 242-252 
    Details
    ISSN: 1617-4623
    Keywords: Arabidopsis ; FUSCA genes ; Photomorphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract More than 200 fusca mutants of Arabidopsis have been isolated and characterised, defining 14 complementation groups. Mutations in at least nine FUSCA genes cause light-dependent phenotypic changes in the absence of light: high levels of anthocyanin accumulation in both the embryo and the seedling, inhibition of hypocotyl elongation, apical hook opening, and unfolding of cotyledons. In double mutants, the fusca phenotype is epistatic to the hy phytochromedeficiency phenotype, indicating that the FUSCA genes act downstream of phytochrome. By contrast, the accumulation of anthocyanin is suppressed by mutations in TT and TTG genes, which affect the biosynthesis of anthocyanin, placing the FUSCA genes upstream of those genes. Regardless of the presence or absence of anthocyanin, fusca mutations limit cell expansion and cause seedling lethality. In somatic sectors, mutant fus1 cells are viable; expressing tissue-specific phenotypes: reduced cell expansion and accumulation of anthocyanin in subepidermal tissue, formation of ectopic trichomes but no reduced cell expansion in epidermal tissue. Our results suggest a model of FUSCA gene action in light-induced signal transduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285451
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Regioselektive Reaktionen an der 17-Oxogruppe von Androsta-1,4-dien-3,17-dion nach in-situ-Schutz mit Titantetrakis(dimethylamid) (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1279-1285 
    Details
    ISSN: 0170-2041
    Keywords: Steroids ; Titanium amides ; Ester enolates ; Dienone-benzene rearrangement ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Regioselective Reactions at the 17-Oxo Group of Androsta-1,4-dine-3,17-dione after in situ Protection with Titaniumtetrakis(dimethylamide)After in situ protection of androsta-1,4-diene-3,17-dione (1) with titaniumtetrakis(dimethylamide) (10) at -20°C to -30°C, the lithium enolates of methyl methoxyacetate (2a) and ethyl acetate (2b) react regio- and stereoselectively at the 17-position to give the 17-hydroxy-17α-pregnanes 12 and 6. Dehydration of 12 and 6 furnishes the 17(20)-olefins 13 and 14, intermediates for the synthesis of corticoids and gestagens. The reaction of 1 with 10 and 2a at -60°C gives byproducts of a dienone-benzene rearrangement of the A-ring. The reactions of 1 with 2a and 2b without titaniumtetrakis-(dimethylamide) (10) proceed regioselectively at the 3-position or nonregioselectively at the 3- and 17-positions, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...