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91.
Steven Gottlieb Paul B. Mackenzie H.B. Thacker Don Weingarten 《Physics letters. [Part B]》1984,134(5):346-350
We present a method for studying hadronic transitions in lattice gauge theory which requires computer time comparable to that required by recent hadron spectrum calculations. This method is applied to a calculation of the decay ?→ππ. 相似文献
92.
Zafrani Y Gottlieb HE Sprecher M Braverman S 《The Journal of organic chemistry》2005,70(24):10166-10168
[reaction: see text] In a recent article, we reported on the base-catalyzed rearrangements of dipropargyl selenides, -sulfides, -sulfoxides, and -sulfones that eventually lead to polycyclic aromatic products. In the present work, we report on the first isolation and characterization of the thiophene dioxide intermediates 5b,c from a mild tandem isomerization/cyclization/aromatization of bis(pi-conjugated propargyl) sulfones. Monoallene 2b,c and diallene 3b intermediates were also identified by NMR. A kinetic study of the rearrangement of 1a-c revealed that the unusual facile tandem process is highly dependent on the nature of gamma-substitution. 相似文献
93.
Aubin C Bernard C Detar C Dipierro M El-Khadra A Gottlieb S Gregory EB Heller UM Hetrick J Kronfeld AS Mackenzie PB Menscher D Nobes M Okamoto M Oktay MB Osborn J Simone J Sugar R Toussaint D Trottier HD;Fermilab Lattice;MILC;HPQCD 《Physical review letters》2005,94(1):011601
We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC Collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently, the systematic error from the chiral extrapolation is much smaller than in previous calculations with Wilson-type light quarks. Our results for the form factors at q(2)=0 are f(D-->pi)(+)(0)=0.64(3)(6) and f(D-->K)(+)(0)=0.73(3)(7), where the first error is statistical and the second is systematic, added in quadrature. Combining our results with experimental branching ratios, we obtain the Cabibbo-Kobayashi-Maskawa matrix elements |V(cd)|=0.239(10)(24)(20) and |V(cs)|=0.969(39)(94)(24), where the last errors are from experimental uncertainties. 相似文献
94.
Light-extinction measurements in the wavelength range of 400 to 1000 nm are performed in situ on Bacillus subtilis endospores during heat-shock-induced activation. Simultaneous information on particle size and refractive indices during activation is calculated from the transmission spectra by use of the Gaussian ray approximation of anomalous diffraction theory. During activation the refractive index of the core decreases from 1.51 to 1.39, and the size increases from 0.38 to 0.6 microm. 相似文献
95.
The crystal structures of T?3PSe4 and T?3AsS4 have been determined by x-ray diffraction techniques. These isomorphous materials are layered, with orthorhombic Pcmn symmetry. Ultrasonic measurements have shown that the shear mode velocity is anomalously low for both materials. Measurements at high pressure on T?3PSe4 have shown that the anomalous shear velocity softens to zero at 1.40 ± 0.01 GPa, indicating a second- order structural transition at that pressure. 相似文献
96.
This paper considers the simultaneous solution of the matrix equations AH + HA1 = A1H + HA = I, where H is Hermitian. A full characterization of A in terms of a given H is obtained. Various results are also obtained for those H satisfying the equations with a given A. 相似文献
97.
For various applications in fluid dynamics, one can assume that the total temperature is constant. Therefore, the energy equations can be replaced by an algebraic relation. The resulting set of equations in the inviscid case is analyzed in this paper. It is shown that the system is strictly hyperbolic and well posed for the initial-value problem. Boundary conditions are described such that the linearized system is well posed. The hopscotch method is investigated and numerical results are presented. 相似文献
98.
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100.
Inactivation of Trypanosoma cruzi Trypomastigote Forms in Blood Components with a Psoralen and Ultraviolet A Light 总被引:1,自引:0,他引:1
Paul Gottlieb Henrietta Margolis-Nunno Richard Robinson Li-Gang Shen Eleanor Chimezie Bernard Horowitz Ehud Ben-Hur 《Photochemistry and photobiology》1996,63(5):562-565
Inactivation of the blood-borne parasite Trypanosoma cruzi by UVA and 4'-aminomethyl-4,5',8-trimethylpsor-alen (AMT) was studied in the blood components fresh frozen plasma (FFP) and platelet concentrate (PC). The AMT was utilized at a concentration of 50 μg/mL and the inactivation procedure included the flavonoid rutin (at 0.35 mM), a quencher of type I and type II photo-reactants, which we have previously found to maintain platelet integrity during this treatment regimen. Within both FFP and PC, complete inactivation of the infective form of T. cruzi , the trypomastigote, was achieved at a UVA (320–400 nm radiation) fluence of 4.2 J/cm2 . We note that while the infectivity of the parasite is eliminated at 4.2 J/cmZ the trypomastigote motility continues for at least 16 h post-treatment and is inhibited only after much higher light doses. Isolation of total DNA from the parasite cells after treatment in the presence of 3 H-AMT indicated that at the lethal UVA fluence about 0.5 AMT adducts per kilobase pairs occurred. These results suggest that this psoralen plus UVA methodology, which shows promise in enhancing the viral safety of PC, may in addition eliminate bloodborne T. cruzi , the causative agent of Chagas disease. 相似文献