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  • 1
    Electronic Resource
    Electronic Resource
    Density-functional study of van der Waals forces on rare-gas diatomics: Hartree–Fock exchange (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 1916-1920 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A density-functional theory study of van der Waals forces on rare-gas diatomics is carried out. Hartree-Fock-Kohn-Sham formalism is used, that is, the exchange-correlation functional is expressed as the combination of Hartree-Fock exchange plus an approximation to the correlation energy functional. Spectroscopic constants (Re,ωe, and De) and potential energy curves for the molecules He2, Ne2, Ar2, HeNe, HeAr, and NeAr are presented. Several approximations to the correlation functional are tested. The best results, in good agreement with reference experimental data, are obtained with the functional proposed by Wilson and Levy [L. C. Wilson and M. Levy, Phys. Rev. B 41, 12930 (1990)]. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477858
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis, Structural Characterization, and Spectroscopic Studies of Heterodimetallic [NBu4][(C6F5)3Pt(.mu.-Pb)(.mu.-X)Pt(C6F5)3] (X = Cl, OH) Complexes (1995)
    s.l. : American Chemical Society
    Inorganic chemistry 34 (1995), S. 6514-6519 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00130a018
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  • 3
    Electronic Resource
    Electronic Resource
    ASTRONOMICAL SEARCHES FOR EARTH-LIKE PLANETS AND SIGNS OF LIFE (1998)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Astronomy and Astrophysics 36 (1998), S. 507-537 
    Details
    ISSN: 0066-4146
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Physics
    Notes: Abstract If Earth-like planets orbit nearby stars, they could be detectable with specially designed telescopes. Direct observations would be very revealing, particularly low resolution infrared spectra, which could establish habitability on the basis of temperature and atmospheric water. Abundant, primitive life based on organized molecular structure might reveal itself, as on Earth, by an atmospheric composition modified in ways unlikely to be from inorganic processes. The technical challenge is to detect and obtain spectra of an object with Mbol~ 28 that is very close to a star and some 5 x 109 times less luminous. Indirect methods, used to detect Jupiter-mass planets, do not seem to offer an easy intermediate step to finding Earth-like planets. However, the direct detection techniques needed for spectroscopy also offer a viable method for discovery by imaging. Thermal infrared wavelengths, in which a planet emits most energy, are the most favorable. A robust search for planets of ~100 nearby solar-type stars, with spectroscopic follow-up of Earth-like candidates, could be made with an interferometer ~75 m in length. In visible light, the Next Generation Space Telescope (NGST) could, with the addition of a high resolution correction instrument, see Earth-like planets around a dozen or so of the nearest stars. Both infrared and optical instruments are possible within the range of current space agency plans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.astro.36.1.507
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  • 4
    Electronic Resource
    Electronic Resource
    A pharmacokinetic comparison of the corn oil versus microemulsion gelcap formulation of cyclosporin used de novo after renal transplantation (1997)
    Springer
    Transplant international 10 (1997), S. 217-222 
    Details
    ISSN: 1432-2277
    Keywords: Key words Cyclosporin ; microemulsion formulation ; Microemulsion formulation ; cyclosporin ; Corn oil ; cyclosporin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The initial poor absorption of the corn oil-based, gel capsule oral formulation of cyclosporin (CyA) greatly limits its use for inception of immunosuppressive therapy. Insufficient drug concentrations during the early post-transplant period predispose to renal allograft rejection. The present study served to compare the time required to achieve therapeutic CyA concentrations after de novo administration of the corn oil-based gel capsule (CyA-GC; n = 11) versus the microemulsion (CyA-ME; n = 11) formulation of CyA. During the 1st month after renal transplantation, patients underwent serial pharmacokinetic profiling from which we obtained observed and dose-corrected values of several parameters. Although patients in neither the CyA-GC nor the CyA-ME group adequately absorbed the drug during days 0–2, from day 3 to 4 patients in the CyA-ME group showed significantly greater absorption than those in the CyA-GC group (P = 0.041). Patients in the CyA-ME group reached the 1st month target average concentration (Cav) values ( ≥ 550 ng/ml) earlier than those in the CyA-GC group and required significantly lower daily CyA doses (P = 0.018). We conclude that therapeutic CyA levels can be achieved more rapidly and with lower doses of the drug after de novo administration of CyA-ME than with CyA-GC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050045
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  • 5
    Electronic Resource
    Electronic Resource
    Structures of ruthenium-modified Pseudomonas aeruginosa azurin and [Ru(2,2′-bipyridine)2(imidazole)2]SO4·10H2O (1999)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 379-385 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The crystal structure of Ru(2,2′-bipyridine)2(imidazole)(His83)azurin (RuAz) has been determined to 2.3 Å resolution by X-ray crystallography. The spectroscopic and thermodynamic properties of both the native protein and [Ru(2,2′-bipyridine)2(imidazole)2]2+ are maintained in the modified protein. Dark-green RuAz crystals grown from PEG 4000, LiNO3, CuCl2 and Tris buffer are monoclinic, belong to the space group C2 and have cell parameters a = 100.6, b = 35.4, c = 74.7 Å and β =  106.5°. In addition, [Ru(2,2′-bipyridine)2(imidazole)2]SO4·10H2O was synthesized, crystallized and structurally characterized by X-ray crystallography. Red–brown crystals of this complex are monoclinic, space group P21/n, unit-cell parameters a = 13.230 (2), b = 18.197 (4), c = 16.126 (4) Å, β = 108.65 (2)°. Stereochemical parameters for the refinement of Ru(2,2′-bipyridine)2(imidazole)(His83) were taken from the atomic coordinates of [Ru(2,2′-bipyridine)2(imidazole)2]2+. The structure of RuAz confirms that His83 is the only site of chemical modification and that the native azurin structure is not perturbed significantly by the ruthenium label.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444998010464
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  • 6
    Electronic Resource
    Electronic Resource
    Imaging circumstellar environments with a nulling interferometer (1998)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 395 (1998), S. 251-253 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Extrasolar planets must be imaged directly if their nature is to be better understood. But this will be difficult, as the bright light from the parent star (or rather its diffracted halo in the imaging apparatus) can easily overwhelm nearby faint sources. Bracewell has proposed a way of ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/26172
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  • 7
    Electronic Resource
    Electronic Resource
    Foraging by a Generalist Grasshopper: The Distance Between Food Resources Influences Diet Mixing and Growth Rate (Orthoptera: Acrididae) (1997)
    Springer
    Journal of insect behavior 10 (1997), S. 829-840 
    Details
    ISSN: 1572-8889
    Keywords: foraging ; grasshopper ; predation risk ; dietary mixing ; Schistocerca ; patch size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The grasshopper, Schistocerca americana, grew better on a mixture of cotton and kale than on either alone. When the two foods were placed in close proximity, growth rates were similar among individuals, but when they were 20 cm apart growth rates were extremely variable among individuals. Behavioral analyses showed that distance influenced the dietary mixing behavior of individuals. Foods close together were sampled more often and there were more meals that included both food types. When foods were distant, individuals tended to stay for relatively long periods at one or the other; when on cotton, this resulted in more feeding on cotton, which was an inferior food. Individuals varied in the extent to which they were constrained by the distance between the two foods. Those that moved between the foods less and therefore mixed less seemed to grow less well, suggesting the possibility of a trade-off between active foraging and behavior associated with predator avoidance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:JOIR.0000010416.54387.44
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  • 8
    Electronic Resource
    Electronic Resource
    Electron transfer in ruthenium-modified proteins (1995)
    Springer
    Journal of bioenergetics and biomembranes 27 (1995), S. 295-302 
    Details
    ISSN: 1573-6881
    Keywords: Electron transfer ; cytochromec ; azurin ; ruthenium ; electronic coupling ; driving-force dependence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Photochemical techniques have been used to measure the kinetics of intramolecular electron transfer in Ru(bpy)2(im)(His)2+-modified (bpy = 2,2′-bipyridine; im = imidazole) cytochromec and azurin. A driving-force study with the His33 derivatives of cytochromec indicates that the reorganization energy (γ) for Fe2+→Ru3+ ET reactions is 0.8 eV. Reductions of the ferriheme by either an excited complex,*Ru2+, or a reduced complex, Ru+, are anomalously fast and may involve formation of an electronically excited ferroheme. The distance dependence of Fe2+→Ru3+ and Cu+→Ru3+ electron transfer in 12 different Ru-modified cytochromes and azurins has been analyzed using a tunneling-pathway model. The ET rates in 10 of the 12 systems exhibit an exponential dependence on metal-metal separation (decay constant of 1.06 å−1) that is consistent with predictions of the pathway model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02110099
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  • 9
    Electronic Resource
    Electronic Resource
    Fluorescence behaviour of polychlorinated dibenzofurans in organized molecular systems. Analytical applications (1995)
    Springer
    Microchimica acta 118 (1995), S. 185-196 
    Details
    ISSN: 1436-5073
    Keywords: spectrofluorimetry ; 2,3,7,8-tetrachlorodibenzofuran ; polyoxyethylene (10) lauryl ether ; C12E10 ; polychlorinated dibenzofurans ; micellar media ; sea water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Fluorescence characteristics of several polychlorinated dibenzofurans (PCDFs) of toxicological and environmental interest in the presence of cationic, anionic, neutral surfactants, α-cyclodextrin and β-cyclodextrin were examined. The fluorescence enhancement of 2,3,7,8-tetrachlorodibenzofuran (TTCDF) in the presence of polyoxyethylene(10) lauryl ether (C12E10) medium was utilized to establish a sensitive spectrofluorimetric method for determination of TTCDF. The optimization of variables as the concentration of surfactant, percentage of organic solvent and temperature, and effect of possible interferences from other PCDFs, polychlorinated dibenzo-p-dioxins (PCCDs), polychlorinated biphenyls (PCBs) and Arochlors were investigated. The method, which has a detection limit of 1.30 ng ml−1, has been applied to the determination of TTCDF in sea water with acceptable recoveries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244358
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  • 10
    Electronic Resource
    Electronic Resource
    Correlation potentials for the He atom and the hydrogen molecule: A comparison between the correlation factor approach and DFT correlation energy functionals (1998)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 67 (1998), S. 143-156 
    Details
    ISSN: 0020-7608
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two points about correlation potentials have been dealt with in this article. The first one is related to the shape of some of the most representative correlation potentials applied to the ground state of the He atom. It is shown here that both LDA and two-body density correlation potentials compare well with that obtained through the quantum chemistry definition of correlation energy. This is an interesting result because, in previous works, it had been shown that none of the correlation potentials compared well with the Kohn-Sham one. The gradient-corrected correlation potentials exhibit a very different behavior to that of both exact potentials (quantum chemistry and Kohn-Sham ones). The other question posed here refers to how a reference to the two-body density must modify DFT functionals for the correlation energy, when a multideterminant wave function is needed. This question has been addressed by analyzing the variation of correlation potentials as the bond length of the H2 molecule increases. The results show that an external reference to the two-body density qualitatively improves DFT correlation potentials and also that only those functionals explicitly depending on two-body density can give the quantitative correct trends.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 143-156, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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