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961.
Compain-Batissou M Latreche D Gentili J Walchshofer N Bouaziz Z 《Chemical & pharmaceutical bulletin》2004,52(9):1114-1116
Oxidation of 2- and 3-hydroxycarbazoles with Frémy's salt gave the corresponding ortho-carbazolequinones. These molecules react as carbodienophiles in Diels-Alder reaction with 1-acetoxy-1,3-butadiene and 1,3-cyclopentadiene to provide the novel benzocarbazolequinone structures 15, 16, 18 and 19. 相似文献
962.
Malak RA Gao Z Wishart JF Isied SS 《Journal of the American Chemical Society》2004,126(43):13888-13889
Long-range electron transfer rate constants for complexes of the type [(bpy)2RuIIL-Pron-apyRuIII)(NH3)5]5++ proline residues (n) varying from 0 to 9 were determined by complementary electron pulse radiolysis and flash photolysis techniques from the picosecond to the millisecond time scales. The activationless kmax values from both techniques coalesce into one data set. The distance dependence of the reactions is consistent with a smooth transition from a superexchange mechanism with attenuation constant beta = 1.4 A-1 to a hopping mechanism with attenuation constant beta = 0.17 A-1. The transition occurs between n = 3 and 4 prolines, and the virtual hopping rate constant at the shortest distance is about 1 x 106 times slower than that observed for the superexchange value. 相似文献
963.
964.
Marcelo Laca Nadia S. Larsen 《Proceedings of the American Mathematical Society》2003,131(7):2189-2199
We consider group-subgroup pairs in which the group is a semidirect product and the subgroup is contained in the normal part. We give conditions for the pair to be a Hecke pair and we show that the enveloping Hecke algebra and Hecke -algebra are canonically isomorphic to semigroup crossed products, generalizing earlier results of Arledge, Laca and Raeburn and of Brenken.
965.
Nadia Ferlazzo Salvatore Condello Monica Currò Giulia Parisi Riccardo Ientile Daniela Caccamo 《BMC neuroscience》2008,9(1):62
Background
Perinatal exposure to hyperhomocysteinemia might disturb neurogenesis during brain development and growth. Also, high levels of homocysteine trigger neurodegeneration in several experimental models. However, the putative mechanisms of homocysteine-induced toxicity in the developing nervous system have poorly been elucidated. This study was aimed to investigate homocysteine effects in undifferentiated neuroblastoma cells, Neuro2a. 相似文献966.
967.
Ohne Zusammenfassung 相似文献
968.
It is demonstrated that a uniform and hyperelastic, but otherwise arbitrary, nonlinear Cosserat rod subject to appropriate end loadings has equilibria whose center lines form two-parameter families of helices. The absolute energy minimizer that arises in the absence of any end loading is a helical equilibrium by the assumption of uniformity, but more generally the helical equilibria arise for non-vanishing end loads. For inextensible, unshearable rods the two parameters correspond to arbitrary values of the curvature and torsion of the helix. For non-isotropic rods, each member of the two-dimensional family of helical center lines has at least two possible equilibrium orientations of the director frame. The possible orientations are characterized by a pair of finite-dimensional, dual variational principles involving pointwise values of the strain-energy density and its conjugate function. For isotropic rods, the characterization of possible equilibrium configurations degenerates, and in place of a discrete number of two-parameter families of helical equilibria, typically a single four-parameter family arises. The four continuous parameters correspond to the two of the helical center lines, a one-parameter family of possible angular phases, and a one-parameter family of imposed excess twists.
Mathematics Subject Classifications (2000) 74K10. 相似文献
969.
Ohne ZusammenfassungTeil einer bei der Naturwissenschaft-Philosophischen Fakultät der Technischen Hochschule Braunschweig eingereichten Dissertation. Referenten: Professor Dr. R. Iglisch und Prof. Dr. H-J. Kanold. Auch Herrn Dr. H. Eltermann bin ich für wertvolle Ratschläge zu Dank verpflichtet. 相似文献
970.
In this paper, we address the preventive health aspects of genetic problems in the Middle East and provide guidelines to prioritize preventive strategies. Applications of various novel genetic techniques such as comprehensive neonatal screening, high throughput heterozygote detection, preimplantation genetic diagnosis, Affymetrix systems, the NanoChip system and a new way of sensitive karyotyping for single-cell chromosome abnormalities are discussed. In conclusion, from the various genetic techniques available, each country should adopt strategies most suitable to its genetic needs and should prioritize the programs to be used in prevention. 相似文献