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991.
Shen-Ting Zhao Ming Chen Shu-Ji Li Ming-Hai Zhang Bo-Xing Li Manas Das Jonathan C Bean Ji-Ming Kong Xin-Hong Zhu Tian-Ming Gao 《BMC neuroscience》2009,10(1):113-8
Background
Caspase-independent apoptotic pathways are suggested as a mechanism for the delayed neuronal death following ischemic insult. However, the underlying signalling mechanisms are largely unknown. Recent studies imply the involvement of several mitochondrial proteins, including endonuclease G (EndoG) and Bcl-2/adenovirus E1B 19 kDa-interacting protein (BNIP3), in the pathway of non-neuronal cells. 相似文献992.
We determine the optimal inner glass ring thickness in infrared air-core photonic bandgap fibers (PBGFs) with 19-cell and 7-cell cores. For PBGFs with a 19-cell core, we find that an inner ring thickness of , where Λ is pitch, yields the widest operational bandwidth, which is nearly 6%. The operational bandwidth increases as the refractive index decreases from 2.8 to 2.0. For PBGFs with a 7-cell core, one needs to draw fiber with a ring thickness of less than to achieve a comparable operational bandwidth. 相似文献
993.
Jonathan Tennyson Peter F. Bernath Linda R. Brown Alain Campargue Michel R. Carleer Attila G. Császár Robert R. Gamache Joseph T. Hodges Alain Jenouvrier Olga V. Naumenko Oleg L. Polyansky Laurence S. Rothman Robert A. Toth Ann Carine Vandaele Nikolai F. Zobov Ludovic Daumont Alexander Z. Fazliev Tibor Furtenbacher Iouli E. Gordon Semen N. Mikhailenko Sergei V. Shirin 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(9-10):573-596
994.
The selfadjoint realization of a second order elliptic differential expression with Dirichlet boundary conditions is shown to be unitarily equivalent to the maximal multiplication operator with the independent variable in an explicit L2 model space. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
995.
Graham Smith Urs D. Wermuth Jonathan M. White 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(7):o464-o468
In the crystal structures of the proton‐transfer compounds of strychnine with 3,5‐dinitrosalicylic acid, namely strychninium 3,5‐dinitrosalicylate, C21H23N2O2+·C7H3N2O7−, (I), and 5‐nitrosalicylic acid, namely strychninium–5‐nitrosalicylate–5‐nitrosalicylic acid (1/1/2), C21H23N2O2+·C7H4NO5−·2C7H5NO5, (II), protonation of one of the N atoms of the strychnine molecule occurs and this group is subsequently involved in intermolecular hydrogen‐bonding interactions. In (I), this is four‐centred, the primary being with an adjacent strychninium carbonyl O‐atom acceptor in a side‐to‐side interaction giving linear chains. Other interactions are with the phenolate and nitro O‐atom acceptors of the anionic species, resulting in a one‐dimensional polymer structure. In (II), the N+—H interaction is three‐centred, the hydrogen bonding involving carboxyl O‐atom acceptors of the anion and both acid adduct species, giving unique discrete hetero‐tetramer units. The structure of (II) also features π‐bonding interactions between the two acid adduct molecules. 相似文献
996.
黄钾铁矾的生物合成与鉴定 总被引:24,自引:1,他引:23
利用氧化亚铁硫杆菌的生物催化氧化作用,在FeSO4—K2SO4—H2O体系中和常温常压条件下合成赭黄色的黄钾铁矾。借助SEM,XRD,FTIR,ICP—AES等方法对它的化学组成和结构进行了分析与表征。结果表明,Thiobacillus ferrooxidans休止细胞可在2天内将FeSO4-K2SO4-H2O体系中的Fe^2 全部氧化为Fe^3 ,Fe^3 在高浓度硫酸根、K^ 存在和酸性条件下水解生成赭黄色高铁沉淀,经鉴定为黄钾铁矾,其晶体粒径均匀,分散性好,且没有无定形的羟基硫酸高铁副产物。 相似文献
997.
Atropisomeric N-methyl-N,N′-diaryl ureas may be obtained in enantiomerically enriched form by oxidative kinetic resolution of their sulfide derivatives. The atropisomeric sulfides may be obtained in up to 97:3 er and display high stability to racemisation (half-lives at 25 °C of up to 500 years). Unlike related fully alkylated ureas, the product sulfoxides exhibit relatively weak thermodynamic conformational selectivity. 相似文献
998.
Effective exposure temperatures (Teff) in Arizona were calculated from hourly or 10-min parsed irradiation data along with ambient, black panel, and sample temperatures. The Teff represents a constant temperature that creates the same amount of photodegradation as the naturally varying temperature and provides a benchmark temperature for making lifetime predictions from accelerated laboratory exposures. The annual ambient and black panel Teff at a Wittmann, Arizona site were 30 °C and 42 °C, respectively, assuming that the photodegradation has an activation energy (Ea) of 21 kJ/mol (5 kcal/mol). Teff was only weakly dependent on Ea over the range of 10-40 kJ/mol (3-10 kcal/mol). Samples exposed as van sunroofs were found to have Teff that were offset from the black panel temperatures by a constant amount for the entire year. Thus, measurements of sample and black panel need to be made for only a few weeks to determine the offset and give the annual sample Teff if the annual black panel Teff is known. Light-colored samples probably are better compared with the ambient temperatures. Sample temperatures in xenon arc exposures usually are higher than the outdoor Teff, so Arrhenius temperature corrections need to be carried out to relate accelerated to outdoor exposures. Temperatures in xenon arc exposure tests often correspond more closely to maximum temperatures that samples might encounter for only a few hours per year. 相似文献
999.
Mohammed K. Abdel-Hamid Jonathan Coates Celia Miländer Brian W. Skelton Anthony C. Willis 《Tetrahedron letters》2009,50(50):6947-8550
The allylation of indigo results in the one-step synthesis of two unique complex heterocyclic systems: a spiroindoline-pyridoindolone arising from the addition of three allyl moieties and a fused pyridoindolo-azepinoindolone generated from the addition and subsequent cyclisation of two allyl moieties. The structures of these novel heterocycles are assigned unambiguously using extensive NMR experiments and by X-ray crystallographic analysis. The distribution of the products is influenced by the use of thermal versus microwave heating. 相似文献
1000.
Jinhua J. Song Zhulin Tan Jonathan T. Reeves Daniel R. Fandrick Heewon Lee Nathan K. Yee Chris H. Senanayake 《Tetrahedron letters》2009,50(27):3952-1877
Treatment of unprotected 5-amino-4-methylpyrimidine (2) with n-BuLi gave dianion 3. Direct condensation of the dianion with various carboxylic acid derivatives furnished a range of 2-substituted-4,6-diazaindoles in good yields in one step without the need for protecting groups or oxidation-state adjustment. 相似文献