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971.
A series of four novel hydrazine-modified diamine conjugates (7a-b, 8a-b) were synthesized and evaluated for cytotoxicity against Melanoma B 16, α-difluoromethylornithine (DFMO)-treated B 16, spermidine (SPD)-treated B 16, Mouse leukemia L 1210 and Hela cell lines. Both the DFMO-B 16 and SPD-B 16 experiments indicated that conjugates 7a-b and 8a-b could recognize the polyamine transporter (PAT) and enter the cells in part or in whole via PAT, although they were not as efficient as the reference, 9- anthracenemethyl homospermidine (1). 2007 Chao Jie Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. 相似文献
972.
Dong-Sheng Hao Jin-Rong Liu Wen-Guang Wu Ju-Cai Yang 《Theoretical chemistry accounts》2009,124(5-6):431-437
The neutral Si n K (n = 2–8) clusters and their anions have been systematically studied by means of the higher level of Gaussian-3 schemes. Equilibrium geometries and electron affinities have been calculated and are discussed for each considered size. For neutral Si n K clusters, the ground state structure is found to be “attaching structure”, in which the K atom is bound to Si n clusters. The most stable isomer for their anions, however, is found to be “substitutional structures”, which is derived from Si(n+1) by replacing the Si atom with a K. The dissociation energies of K atom from the lowest energy structures of Si n K have also been estimated to examine relative stabilities. 相似文献
973.
Yan Ling Lia Hao Fang 《中国化学快报》2008,(5)
As an important intermediate to study cyclin-dependent kinase(CDK)inhibitors,2-aryl-8-(piperidin-4-yl)-5,7-dimethoxy-4H- chromen-4-one derivatives were prepared usingβ-diketone route with low yield.In our study,chalcone route has been investigated and the result suggested that the benzaldehydes substituted with electron-donating group give much better yield thanβ-diketone route.This new method will be an efficient way to start further research on new anticancer flavonoids. 相似文献
974.
In this paper, general conditions of state classification for the total weighted occupation times of a class of infinitely
divisible superprocesses on a bounded domain D in ℝ
d
are given. As an application, some sufficient and necessary conditions are found for the total weighted occupation times
of some special superprocesses on D to be absolutely continuous or singular with respect to the Lebesgue measure on D.
The research of Yan-Xia Ren is supported by NNSF of China (Grant No. 10471003) and Foundation for Authors Awarded Excellent
Ph.D. Dissertation. 相似文献
975.
The enlargement of the emitting aperture is usually one of the important methods of increasing vertical- cavity surface-emitting laser (VCSEL) optical output power. However, in a VCSEL with a larger aperture, the inhomogeneity in the injected current often causes inhomogeneous or even no emission. To solve this problem and to increase VCSEL output power, as well as to improve its thermal characteristics, we develop a new type of injected VCSEL with a larger aperture and a reticular electrode, where the conventional circular injection electrode of the P side is turned into a reticular one, and the heat sink is on the N side. The tests of the new VCSEL show an improvement in homogeneity in not only the injected current but also the emission intensity. The optical output power is also considerably increased, and the device optoelectronic performance is improved. 相似文献
976.
977.
978.
Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_2 molecule 总被引:2,自引:1,他引:1
REN Weiyi SUN Weiguo HOU Shilin & FENG Hao . Institute of Physics College of Chemical Engineering Sichuan University Chengdu China . Institute of Theoretical Physics Xihua Normal University Nanchong China . Department of Physics China Oceanography University Qingdao China . College of Physics Sichuan University Chengdu China 《中国科学G辑(英文版)》2005,48(4)
1 IntroductionAccurate results of high-lying vibrational energies and molecular dissociation energy De of diatomic electronic states are very important for thermodynamics, molecular spec- troscopy, reactive scatterings, and the collision physics of ultracold atoms. For example, the binding energy of the highest bound vibrational state to the ground vibrational state determines the s-wave scattering length. This in turn determines the low- energy (pre- dominantly s-wave) atomic elastic-scatteri… 相似文献
979.
Bailin Hao 《Journal of statistical physics》2005,121(5-6):749-757
This is a brief review on critical slowing down near the Feigenbaum period-doubling bifurcation points and its consequences.
The slowing down of numerical convergence leads to an “operational” fractal dimension D=2/3 at a finite order bifurcation point. There is a cross-over to D
0=0.538... when the order goes to infinity, i.e., to the Feigenbaum accumulation point. The problem of whether there exists
a “super-scaling” for the dimension spectrum D
q
W
that does not depend on the primitive word W underlying the period-n-tupling sequence seems to remain open 相似文献
980.