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71.
A. Gallegos Saliner I. Tsakovska M. Pavan G. Patlewicz A. P. Worth 《SAR and QSAR in environmental research》2013,24(3-4):331-342
The German Federal Institute for Risk Assessment (BfR) has developed a Decision Support System (DSS) to assess certain hazardous properties of pure chemicals, including skin and eye irritation/corrosion. The BfR–DSS is a rule-based system that could be used for the regulatory classification of chemicals in the European Union. The system is based on the combined use of two predictive approaches: exclusion rules based on physicochemical cut-off values to identify chemicals that do not exhibit a certain hazard (e.g., skin irritation/corrosion), and inclusion rules based on structural alerts to identify chemicals that do show a particular toxic potential. The aim of the present study was to evaluate the structural inclusion rules implemented in the BfR–DSS for the prediction of skin irritation and corrosion. The following assessments were performed: (a) a confirmation of the structural rules by rederiving them from the original training set (1358 substances), and (b) an external validation by using a test set of 200 chemicals not used in the derivation of the rules. It was found as a result that the test data set did not match the training set relative to the inclusion of structural alerts associated with skin irritation/corrosion, albeit some skin irritants were in the test set. 相似文献
72.
研究了钛酸钡和钛酸钙担载的Ag和Pt纳米催化剂的表面结构随氧化-还原处理过程的动态变化及其对CO完全氧化反应性能的影响.发现氧化物担载的Ag催化剂在氧化处理后其催化活性较还原处理的高; X射线衍射(XRD)和X射线光电子能谱(XPS)表征结果表明,氧化处理能够提高载体表面Ag颗粒的分散度,而还原处理导致Ag颗粒的聚集,从而降低了催化氧化CO反应的活性.氧化-还原处理改变了担载Ag纳米粒子的尺寸并影响其CO氧化反应活性.与此相反,氧化物担载的Pt催化剂在还原处理后所表现出的CO氧化反应活性较氧化处理的高; 对比研究发现,氧化和还原处理后Pt纳米粒子的尺寸基本相同,但是氧化处理的样品中Pt表面物种以氧化态为主,而还原处理后Pt表面物种主要为金属态.Pt纳米粒子表面化学状态随氧化-还原处理的调变是导致表面催化活性差异的主要原因. 相似文献
73.
Saikat Haldar Balaji S. Kale Dipesh D. Jadhav Hirekodathakallu V. Thulasiram 《Tetrahedron letters》2014
Pentacyclic triterpenoids α- and β-amyrin possess a wide range of biological and pharmacological activities. High structural similarity between these two structural isomers makes their chromatographic separation an ineffective and tedious choice. In this study, Candida rugosa lipase catalyzed separation protocol for the isolation of individual isomers has been developed. In the presence of vinyl acetate as the acyl donor, Candida rugosa lipase carried out acetylation of β-amyrin more efficiently as compared to α-amyrin leading to a kinetic separation. The conditions of transesterification reaction were optimized systematically, which was utilized to separate α- and β-amyrin from a mixture obtained from the latex of Plumeria obtusa. 相似文献
74.
Feng-Peng Wang Dong-Lin Chen Hong-Ying Deng Qiao-Hong Chen Xiao-Yu Liu Xi-Xian Jian 《Tetrahedron》2014
We have corrected (Tetrahedron2013, 69, 5859–5866) the structures of diterpenoid alkaloids reported in the Journal of Natural Products2012, 75, 1145–1159. Our follow-up experiments compel us to present further revisions and clarifications on the diterpenoid alkaloids: 相似文献
75.
电催化二氧化碳还原反应(E-CO2RR)可在温和条件下将CO2转化成高附加值燃料或化学品,近年来受到广泛关注,其在实际反应中涉及到气体扩散和多电子转移等复杂过程,构筑高效、稳定的催化电极是其发展的核心之一。然而,传统涂敷电极制备时,需要将催化剂与粘结剂混合涂覆于集流体表面,此过程会造成活性位点包埋和传质过程受限,致使催化剂活性位利用率下降,同时在反应过程中电极表面容易粉化,造成稳定性下降,难以重复利用。因此,如何调控电极反应界面,提升催化剂活性位的利用率仍面临挑战。将催化剂原位生长于集流体上得到的一体化电极可直接应用于电催化反应,不仅有利于提升活性位利用率以及电荷传输能力,还能有效调控三相界面处的微观反应环境(如pH、反应物及反应中间体的浓度等),从而实现电催化性能强化。本文综述了一体化电极用于E-CO2RR的最新进展,分析了结构和表界面调控对E-CO2RR性能的影响规律,并对该领域仍然存在的挑战和未来一体化E-CO2RR电极的发展进行了评述与展望。 相似文献
76.
77.
Bulk assemblies of zero-dimensional (0D) metal halides with ‘host-guest’ system provide a promising platform for rationally structural tunability and photoluminescence modulation. In this work, we first report a series of ternary 0D metal halides, (bmpy)9[Pb3Cl11](MnCl4)2-2x(SbCl5)2x (bmpy+ = 1-buty-1-methylpyrrolidinium+, C9NH20+), where the organic cation bmpy+ cocrystallizes with [Pb3Cl11]5- trimer clusters, [MnCl4]2? tetrahedra, and [SbCl5]2? pyramids. The emission color of (bmpy)9[Pb3Cl11](MnCl4)2-2x(SbCl5)2x can be easily tuned from green to warm white and finally to orange-red by controlling the excitation wavelength or the [SbCl5]2?/[MnCl4]2? molar ratio, promising its potential for application in multicolor light-emitting devices or even in encrypting multilevel optical codes. This work presents a novel structural modulation strategy to fabricate superior ordered single-crystalline multicomponent materials with multifunctionalities of 0D luminescent metal halides. 相似文献
78.
Laredo E Prutsky N Bello A Grimau M Castillo RV Müller AJ Dubois P 《The European physical journal. E, Soft matter》2007,23(3):295-303
Thermally stimulated depolarization currents, TSDC, wide-angle X-ray scattering, WAXS, differential scanning calorimetry,
DSC, and polarized light optical microscopy, PLOM, have been used to examine poly(L-lactide)-b -poly(
-caprolactone) diblock copolymers in a wide composition range. Both components are crystallizable and the miscibility in
the amorphous phase has been determined from the behavior of the primary relaxations which are the dielectric manifestation
of the glass transition, and also from the superstructural morphology revealed by PLOM and the compositional dependence of
the melting points as determined by DSC. Distinct segmental mobilities in the amorphous phase which can be well resolved by
TSDC are present; the
mode of the slower component shifts to lower temperatures as the PCL content increases while the glass transition of neat
PCL is present for all compositions. A relaxation times bimodal distribution is apparent for PCL-rich copolymers. The composition
dependence of the multiple glass transitions detected in these weakly segregated copolymers are predicted by the self-concentration
model for a miscible blend made of components with a large Tg contrast. 相似文献
79.
《印度化学会志》2021,98(12):100250
Within this work, two novel Cu(II) and Mn(II)-based coordination polymers (CPs) along with chemical compositions of {[Cu2(L1)(1,4-NDC)2]·3H2O}n (1, 1,4-H2NDC = Naphthalene-1,4-dicarboxylic acid, L1 = di(1H-imidazole-1-yl)methane) and [Mn3(L2)2(H2O)2(1,4-NDC)2]n (2, L2 = 1,4-di(1H-imidazole-1-yl)benzene) have been completed in success via related metal salts reaction with 1,4-H2NDC ligand in existence of various N-donor co-ligands. We discovered its application values on the surgical site infections (SSI) along with corresponding mechanism in the interim. We evaluated inflammatory cytokines released into the urine through ELISA detection kit after compound treatment. Then, we discovered the inhibitory effect of compound on the bacterial biofilm formation via real time RT-PCR. 相似文献
80.
中空多壳层结构(HoMSs)是一种以纳米颗粒为结构单元构筑而成的具有多界面、 多维度的微纳米级宏观组装体, 具有次序排列的多个壳层及相互连通的多个空腔, 被认为是电磁波领域极具应用前景的功能材料. 本文主要从电磁波捕获、 传输及能量转换3个角度详细阐述HoMSs在电磁波领域应用中的独特优势, 浅析了HoMSs壳层数目、 壳层厚度、 壳层间距、 壳层组成等结构参数对电磁波传输与利用的影响规律, 并预测了HoMSs在电磁波领域的发展趋势, 以期为实现电磁波的高效利用提供参考. 相似文献