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KL Britton HF Rogers Y Asano T Dairi Y Kato TJ Stillman DW Rice 《Acta crystallographica. Section D, Biological crystallography》1998,53(4):124-126
The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificites. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 ? resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 ? and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres. 相似文献
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A. E. S. Green G. B. Findley Jr. K. F. Klenk W. M. Wilson T. Mo 《Photochemistry and photobiology》1976,24(4):353-362
Abstract— We correlate annual ultraviolet dose estimates with age specific and age adjusted incidence data for non-melanoma skin cancer in the United States, United Kingdom, Canada and Australia. We first examine (1) a reciprocity or photographic model in which incidence rates (R) are related to exposure (E) which is the product of age (T) and annual dose (D). We also test several models which violate reciprocity including models identified by the labels: (2) Dose potency; (3) Double cause; (4) Age-exposure and (5) separable. Our analyses together with the recent National Cancer Institute study favors the age-exposure model and/or the double cause models. All models lead to biological amplification factors (defined as the ratio of the percent increase in skin cancer incidence due to a 1% increase in dose) greater than unity. For the U.S. we find the biological amplification to be approximately 1.8 for the population center but greater in regions of higher UV annual dose, and less in regions of lower annual UV dose. 相似文献
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An intermediate coupling analysis of the low-energy π → σ Rydberg transitions of hydrogen bromide, cyanogen bromide, acetylene bromide and alkyl bromides is presented. Exchange and spin-orbit coupling parameters are calculated and their variations discussed. The Br 5s orbital is delocalized in the larger alkyl bromides and Br 4p is heavily involved in π bonding in acetylene and cyanogen bromides. 相似文献
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A. Saifer M. Kornblum S. P. Worden I. B. Rushing I. P. Barnes A. P. Surer M. Farren Greta Hammarsten B. Melichar L. Vsetecka S. A. Poworinskaja Raimonde Duval J. M. Le Goff E. Justin-Mueller G. Haslewood E. King A. T. Cameron J. S. Guthrie F. D. White Th. Findley Regine Kapeller-Adler N. P. Meschkowa Rangier Lafrançaise P. A. Clifford H. J. Wichmann F. Timm E. Komm F. Kiermeier und A. Douglas-Sauermann 《Fresenius' Journal of Analytical Chemistry》1938,115(7-8):296-300
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This survey reviews work dealing either directly or indirectly with initial and subsequent yield surfaces. Emphasis is placed primarily on experimental investigations. Features of the work surveyed which are discussed include motivation, discrepancies, attempts to overcome discrepancies, and the nature of further work needed. 相似文献
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Vacuum ultraviolet photoabsorption spectra of CH3I 6s and 6s′ Rydberg states doped into supercritical argon, krypton, and xenon perturbers were measured from low density to the density of the triple point liquid at noncritical temperatures and on an isotherm near the perturber critical temperature. A full line shape analysis of these spectra was performed using a single set of intermolecular potential parameters for each dopant/perturber system. The resulting perturber induced shift of the simulated adiabatic transition of the 6s and 6s′ Rydberg states is presented as a function of perturber number density, and this shift illustrates a perturber critical point effect on the excitation energies of the molecular low-n Rydberg states. 相似文献
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Homogeneous broadening of one of the 5D1←7F0 absorption lines of Eu3+ in PbF2 was measured in the temperature range 300–800 K. Below 625 K the linewidth depends linearly on T; above 625 K it increases rapidly followed by a plateau beginning near 700 K. This behavior is quite distinct from that expected for the normal Raman process in crystalline materials and appears to be correlated with F- ion motion responsible for the superionic conductivity of PbF2. 相似文献