排序方式: 共有122条查询结果,搜索用时 164 毫秒
81.
Dušan S. Dimić Dejan A. Milenković Jasmina M. Dimitrić Marković 《Molecular physics》2018,116(9):1166-1178
The antiradical potency of catecholamines (dopamine, epinephrine, norepinephrine, L-DOPA), metabolites of dopamine (homovanillic acid, 3-methoxytyramine and 3,4-dihydroxyphenylacetic acid) and catechol towards substituted methylperoxy radicals is investigated. The thermodynamic parameters, together with the kinetic approach, are used to determine the most probable mechanism of action. The natural bond orbital and quantum theory of atoms in molecules are utilised to explain the highest reactivity of trichloromethylperoxy radical. The preferred mechanism is dependent both on the thermodynamic and kinetic parameters . The number of chlorine atoms on radical, the presence of intra-molecular hydrogen bond and number of hydroxy groups attached to the aromatic ring significantly influence the mechanism. The results suggest that sequential proton loss electron transfer (SPLET) is the most probable for reaction with methylperoxy and hydrogen atom transfer (HAT) for reaction with trichloromethylperoxy radicals, with a gradual transition between SPLET and HAT for other two radicals. Due to the significant deprotonation of molecules containing the carboxyl group, the respective anions are also investigated. The HAT and SPLET mechanisms are highly competitive in reaction with MP radical, while the dominant mechanism towards chlorinated radicals is HAT. The reactions in methanol and benzene are also discussed. 相似文献
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A simple model of a portfolio allocation between mature and emerging markets is specified. The representative-agent, rational expectations version of the model has an unlimited number of equilibria, providing no reason to expect that heterogeneous agents would all coordinate on one or another equilibrium. Therefore, the model is simulated with heterogeneous expectations based on ex post returns, imitation, and experimentation. Solutions produce periodic crises, as periods of excessive optimism plant the seed for their reversal, despite the fact that interest rates fall before crises, instead of rising. 相似文献
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Stevanović M Savić J Jordović B Uskoković D 《Colloids and surfaces. B, Biointerfaces》2007,59(2):215-223
Ascorbic acid (vitamin C) is essential for preserving optimal health and is used by the body for many purposes. The problem is that ascorbic acid easily decomposes into biologically inactive compounds making its use very limited in the field of pharmaceuticals, dermatological and cosmetics. By encapsulating the ascorbic acid into a polymer matrix it is assumed that its chemical instability can be overcome as well as higher, more efficient and equally distributed concentration throughout extended period of time can be achieved. This paper is describing the process of obtaining poly(dl-lactide-co-glycolide) (DLPLG) nanospheres (110-170 nm) using chemical method with solvent/non-solvent systems where obtained solutions have been centrifuged. The encapsulation of the ascorbic acid in the polymer matrix is performed by homogenisation of water and organic phases. Nanoparticles of the copolymer DLPLG with the different contents of the ascorbic acid have different morphological characteristics, i.e. variable degree of uniformity, agglomeration, sizes and spherical shaping. The degradation of the nanospheres of DLPLG, DLPLG/ascorbic acid nanoparticles and release rate of the ascorbic acid were studied for 8 weeks in a physiological solution (0.9% sodium chloride in water). The samples have been characterised by infrared spectroscopy (IR), scanning electron microscopy (SEM), stereological analysis and ultraviolet (UV) spectroscopy. 相似文献
84.
Tenjović Branislava Stojković Ivana Nikolov Jovana Todorović Nataša Spasojević Jelena Agbaba Jasmina Pajić Marija Krmar Miodrag 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(3):679-686
Journal of Radioanalytical and Nuclear Chemistry - A separation procedure was developed and implemented for the isolation of gold (Au) and platinum (Pt) radionuclides from deuteron irradiated Pt... 相似文献
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Djaković Senka Maračić Silvija Lapić Jasmina Kovalski Eduard Hildebrandt Alexander Lang Heinrich Vrček Valerije Raić-Malić Silvana Cetina Mario 《Structural chemistry》2021,32(6):2291-2301
Structural Chemistry - Ferrocenyl-, triazole- and quinoline-containing compounds are known to possess potential for biological activities. The synthesis and biological activities of O-alkylated... 相似文献
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Smječanin Narcisa Nuhanović Mirza Sulejmanović Jasmina Grahek Željko Odobašić Amra 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(3):1459-1471
Journal of Radioanalytical and Nuclear Chemistry - Red beet peel was utilized for U(VI) removal in a batch system. The characterization of prepared biosorbent was performed by Fourier transform... 相似文献
89.
Siljegović J Glamoclija J Soković M Vucković I Tesević V Milosavljević S Stesević D 《Natural product communications》2011,6(2):263-266
The essential oil isolated from Seseli montanum L. subsp. tommasinii Reich. f. was analyzed by GC/MS and the most abundant components were beta-pinene (30.2%), germacrene D (10.1%), sabinene (8.0%), alpha-pinene (7.2%) and limonene (6.6%). The antimicrobial effect of the essential oil was evaluated against four bacterial and four fungal species among which were food contaminants, spoilage fungi, and plant, fungal and animal pathogens. The oil possessed moderate to strong antimicrobial activity. 相似文献
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Ines Hafizovic Carl-Inge Colombo Nilsen Morgan Kjølerbakken Vibeke Jahr 《Applied Acoustics》2012,73(2):132-143
Despite many attractive features and the potential for capturing sound in challenging acoustic environments, arrays with a large number of microphones have for a long time been discarded as a practical solution for speech acquisition. This is, among other reasons, due to the high production and computational costs. Only a few realizations of large microphone array systems have been documented, mainly for research and instrumentation use. The advent of MEMS microphones and computationally powerful off-the-shelf hardware has created new possibilities for microphone array development. We investigate a real life application, specifically the case of live sports broadcast, and the requirements that a such application imposes on a microphone array system. We present a system architecture of the first large (300 element circular array with a diameter of 2 m) MEMS microphone array system. In the proposed system, the latest technological advances are utilized to create a user-friendly array control interface. The array’s performance is examined in an anechoic chamber and on a crowded basketball field, and finally compared with existing solutions. The results illustrate the potential of a large MEMS microphone array as part of the technological development in sound acquisition for entertainment and security applications. 相似文献