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21.
ANKA is a relatively new synchrotron radiation facility at the Forschungszentrum Karlsruhe, a large government research center in the southwest of Germany. The acronym stands for Angstrom Source Karlsruhe. The electron storage ring is 110.4 m in circumference and stores a 2.5 GeV electron beam at a typical current of 200 mA. The facility has been open for users since March 2003. 相似文献
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A. R. Cunningham S. L. Cunningham D. M. Consoer S. T. Moss M. H. Karol 《SAR and QSAR in environmental research》2013,24(3):273-285
Structure–activity relationship (SAR) models are recognized as powerful tools to predict the toxicologic potential of new or untested chemicals and also provide insight into possible mechanisms of toxicity. Models have been based on physicochemical attributes and structural features of chemicals. We describe herein the development of a new SAR modeling algorithm called cat-SAR that is capable of analyzing and predicting chemical activity from divergent biological response data. The cat-SAR program develops chemical fragment-based SAR models from categorical biological response data (e.g. toxicologically active and inactive compounds). The database selected for model development was a published set of chemicals documented to cause respiratory hypersensitivity in humans. Two models were generated that differed only in that one model included explicate hydrogen containing fragments. The predictive abilities of the models were tested using leave-one-out cross-validation tests. One model had a sensitivity of 0.94 and specificity of 0.87 yielding an overall correct prediction of 91%. The second model had a sensitivity of 0.89, specificity of 0.95 and overall correct prediction of 92%. The demonstrated predictive capabilities of the cat-SAR approach, together with its modeling flexibility and design transparency, suggest the potential for its widespread applicability to toxicity prediction and for deriving mechanistic insight into toxicologic effects. 相似文献
24.
Eight examples of sec-alkyl isouronium salts were readily prepared from sec-alcohols, cynamide, and methanesulfonic acid (or CF3SO3H or HBF4). 相似文献
25.
Jinny Claire Lee Hye Yun Kim Sejin Lee Jisu Shin Hyunjin Vincent Kim Kyeonghwan Kim Seungyeop Baek Donghee Lee Hanna Jeon DaWon Kim Seung‐Hoon Yang Gyoonhee Han Keunwan Park Jaeho Choi Jinwoo Park Jason A. Moss Kim D. Janda YoungSoo Kim 《Angewandte Chemie (International ed. in English)》2020,59(28):11491-11500
Amyloid‐β (Aβ) oligomers are implicated in Alzheimer disease (AD). However, their unstable nature and heterogeneous state disrupts elucidation of their explicit role in AD progression, impeding the development of tools targeting soluble Aβ oligomers. Herein parallel and anti‐parallel variants of Aβ(1–40) dimers were designed and synthesized, and their pathogenic properties in AD models characterized. Anti‐parallel dimers induced cognitive impairments with increased amyloidogenesis and cytotoxicity, and this dimer was then used in a screening platform. Through screening, two FDA‐approved drugs, Oxytetracycline and Sunitinib, were identified to dissociate Aβ oligomers and plaques to monomers in 5XFAD transgenic mice. In addition, fluorescent Astrophloxine was shown to detect aggregated Aβ in brain tissue and cerebrospinal fluid samples of AD mice. This screening platform provides a stable and homogeneous environment for observing Aβ interactions with dimer‐specific molecules. 相似文献
26.
L. Haeggqwist L. Schimansky-Geier I. M. Sokolov F. Moss 《The European physical journal. Special topics》2008,157(1):33-42
We study the diffusion coefficient of Active Brownian particles in
two dimensions. In addition to usual attributes of active motion we
let the particles turn in preferred directions over random times.
This angular motion is modeled by an effective Lorentz force with
time dependent frequency switching between two values at
exponentially distributed random times. The diffusion coefficient is
calculated by the Taylor-Kubo formula where distributions found from
a Fokker-Planck equation or from a continuous time random walk
approach have been inserted for averaging. Eventually properties
of the diffusion coefficient will be discussed. 相似文献
27.
Conditions have been found for the efficient palladium mediated cyclisation-carbonylation of bromodienes to give gamma,lambda-unsaturated acids. 相似文献
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[reaction: see text] The copper metallomicellar hydrolysis of O-methyl O-4-nitrophenyl phenylphosphonothioate to O-methyl phenylphosphonothioic acid takes place with effectively complete inversion at phosphorus. 相似文献
29.
Neiman A Schimansky-Geier L Moss F Shulgin B Collins JJ 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(1):284-292
We study, in terms of synchronization, the nonlinear response of noisy bistable systems to a stochastic external signal, represented by Markovian dichotomic noise. We propose a general kinetic model which allows us to conduct a full analytical study of the nonlinear response, including the calculation of cross-correlation measures, the mean switching frequency, and synchronization regions. Theoretical results are compared with numerical simulations of a noisy overdamped bistable oscillator. We show that dichotomic noise can instantaneously synchronize the switching process of the system. We also show that synchronization is most pronounced at an optimal noise level-this effect connects this phenomenon with aperiodic stochastic resonance. Similar synchronization effects are observed for a stochastic neuron model stimulated by a stochastic spike train. 相似文献
30.