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61.
62.
[reaction: see text] Data are presented indicating that the potent antitumor activity of 2-crotonyloxymethyl-(4R,5R,6R)-4,5,6-trihydroxy-2-cyclohexenone (COTC) and 2-crotonyloxymethyl-2-cyclohexenone (COMC) is not likely the result of glyoxalase I inhibition, as has long been assumed. An alternative hypothesis is presented, based on the finding that COMC is a substrate for human glutathionyl transferase, which produces a transient, highly electrophilic glutathionylated 2-exomethylenecyclohexanone that can covalently modify proteins and nucleic acids. 相似文献
63.
[reaction: see text] The conjugate addition of methyl (S)-(2-piperidyl)acetate (3) to 2-(3,4-dimethoxyphenyl)-1-(p-toluenesulfonyl)ethyne (4), followed by LDA-promoted intramolecular acylation, stereoselective reduction, and desulfonylation, afforded (-)-lasubine II. 相似文献
64.
Reilly DJ Buehler TM O'Brien JL Hamilton AR Dzurak AS Clark RG Kane BE Pfeiffer LN West KW 《Physical review letters》2002,89(24):246801
There is controversy as to whether a one-dimensional (1D) electron gas can spin polarize in the absence of a magnetic field. Together with a simple model, we present conductance measurements on ultra-low-disorder quantum wires supportive of a spin polarization at B=0. A spin energy gap is indicated by the presence of a feature in the range (0.5-0.7)x2e(2)/h in conductance data. Importantly, it appears that the spin gap is not constant but a function of the electron density. Data obtained using a bias spectroscopy technique are consistent with the spin gap widening further as the Fermi level is increased. 相似文献
65.
W.C. Ma A.V. Ramayya J.H. Hamilton S.J. Robinson M.E. Barclay K. Zhao J.D. Cole E.F. Zganjar E.H. Spejewski 《Physics letters. [Part B]》1984,139(4):276-278
The energy levels of 182Hg have been identified for the first time through comparison of in-beam studies of the reactions 156,154Gd(32S, 4n)184,182Hg and γ-X-ray coincidences. Levels up to 12+ in 182Hg were established from γ-γ coincidences and singles measurements. The data establish that the ground state shape is near spherical, and that the ground band is crossed by a well-deformed band at 4+. In contrast to IBA model predictions that the deformed band will rise in energy in 182Hg compared to 184Hg, the energies of the deformed levels in 182Hg continue to drop. 相似文献
66.
K. R. Baker J. H. Hamilton A. V. Ramayya 《Zeitschrift für Physik A Hadrons and Nuclei》1972,256(5):387-415
The decay of 12.4 y152Eu to152Sm and152Gd was studied in a high resolution singles measurement and two 4096×2048 Ge(Li)-Ge(Li) coincidence studies. Forty-five gates were analyzed in order to confirm or establish the placement of the γ rays as well as to accurately determine the intensities of the 12 doublets, which included several not previously reported. A new γ-β interband transition, 4 γ + →2 β + (561.4 keV), a possible 3 γ + →2 β + (423.7 keV) transition, and a new 330.9 keV transition between the 4 γ + level and theI π K=3?0 octupole level were established from coincidence data. Levels at 1757.0 keV in152Sm and 1282.5, 1318.7, and 1692.2 keV in152Gd are now established on the basis of coincidence data. These data also establish for the first time the population in the152Eu decay levels at 1680.0 and 1047.9 keV in152Sm and152Gd, respectively, as well as a new level at 1700.8 keV in152Sm. 相似文献
67.
Total luminescence yield of toluene and mesitylene, isolated in rare-gas matrices, has been measured as a function of excitation energy in the energy range covering the absorption region of both host and guest. Energy transfer from the host to the dopant is apparent. An increase in the luminescence yield is observed at the host exciton state. Luminescence excitation spectrum of pure mesitylene is presented. 相似文献
68.
Recent calculations have shown that grain boundary (GB) stress is too small to stabilize finite GB facets, suggesting that the existing theory of GB defaceting phase transitions is incomplete. We perform molecular dynamics calculations, which show a reversible phase transition at approximately 400 K with a concerted shuffle of two atoms at the facet junction as the elementary excitation. Based on this excitation we formulate an appropriate lattice model, perform Monte Carlo simulations, and establish an analytical relationship between the elementary excitation energy and the transition temperature. 相似文献
69.
Cobb SL Deng H Hamilton JT McGlinchey RP O'Hagan D 《Chemical communications (Cambridge, England)》2004,(5):592-593
5'-Fluoro-5'-deoxy-D-ribose-1-phosphate (FDRP) is identified as a biosynthetic intermediate during fluorometabolite biosynthesis in Streptomyces cattleya. 相似文献
70.
The design of synthetic agents to disrupt protein-protein interactions has received relatively little attention in recent years. In this review we describe strategies for targeting different types of protein surfaces using mimetics of protein secondary or tertiary structure. In this way strong and selective binding to a protein surface has be achieved and disruption of clinically important protein-protein interactions has been demonstrated in models of human disease. 相似文献