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排序方式: 共有407条查询结果,搜索用时 15 毫秒
1.
Markovic Maja D. Seslija Sanja I. Ugrinovic Vukasin Dj. Kunaver Matjaz Panic Vesna V. Pjanovic Rada V. Spasojevic Pavle M. 《Cellulose (London, England)》2021,28(17):11109-11132
Cellulose - pH- and magnetic-sensitive hybrid hydrogels based on poly(methacrylic acid) (PMAA), nanocellulose (NC), carboxymethyl cellulose (CMC) and magnetite particles (MN) were prepared as... 相似文献
2.
D. Živković M. Sokić Ž. Živković D. Manasijević Lj. Balanović N. Štrbac V. Ćosović B. Boyanov 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1173-1176
The results of thermal study and mechanism of the oxidation process of synthetic Ag2S in air are presented in this article based on the comparative analysis of DTA and XRD results, as well as by constructed phase stability diagrams (PSD) for the Ag–S–O system. 相似文献
3.
4.
Glavnik Vesna Simonovska Breda Vovk Irena Pavlović Dragana Mutavdžić Ašperger Danijela Babić Sandra 《平面色谱法杂志一现代薄层色谱法》2011,24(6):482-486
JPC – Journal of Planar Chromatography – Modern TLC - Validation of a method for the quantification of (−)-epicatechin and procyanidin B2 in chocolates is reported. After a simple... 相似文献
5.
Mirjana Popsavin Vesna Kojić Saša Spaić Miloš Svirčev Gordana Bogdanović Dimitar Jakimov Lidija Aleksić Velimir Popsavin 《Tetrahedron》2014
Tiazofurin analogues bearing a 5-hydroxymethyl-2-methyl-tetrahydrofuro[2,3-d][1,3]dioxol-6-ol moiety as a sugar mimic (2 and 3), and two novel thiazole-based acyclo-C-nucleosides 4 and 16 have been synthesized in multistep sequences starting from d-xylose (compounds 2 and 3) or from d-arabinose (compounds 4 and 16). All synthesized analogues showed potent in vitro antitumour activities against a panel of human tumour cell lines. Flow cytometry data suggest that cytotoxic effects of analogues 2–4 and 16 in the culture of K562 cells might be mediated by apoptosis. It was also found that these analogues induced changes in cell cycle distribution of K562 cells. Results of western blot analysis (upregulation of Bax and downregulation of Bcl-2, activation of caspase-3 and the presence of a PARP cleavage product) suggest that tiazofurin mimics (2–4 and 16) in K562 cells induced apoptosis in a caspase-dependent way. 相似文献
6.
Zorica Vujić Milkica Crevar Vladimir Obradović Vesna Kuntić Snežana Uskoković-Marković 《Chromatographia》2009,70(7-8):1221-1225
A rapid and simple liquid chromatographic method with UV detection has been developed for the determination of hydrochlorothiazide (HCTZ), cilazapril (CL) and its active metabolite cilazaprilat (CLT) in urine. Sample preparation for urine consisted of solid-phase extraction using styrene-divinylbenzene (SDB-2) cartridges. The chromatographic system was a Zorbax Eclipse XDB-C18 column with a mixture of methanol and 10 mM phosphate buffer, pH 2.3 with gradient (20 to 60% of methanol) as mobile phase at a flow rate of 1.0 mL min?1. The detection was performed at the wavelength of 206 nm. Enalapril maleat was used as an internal standard. The detector response was linear in the range of 2.4–30.0, 1.6–15.0 and 1.8–20.0 μg mL?1 for HCTZ, CL and CLT, respectively. LOQ was determined to be 2.4, 1.6 and 1.8 μg mL?1 for HCTZ, CL and CLT, respectively. Both intra- and inter-day precision were within acceptable limits. The method has been applied to urine samples obtained from three hypertensive patients after intake of HCTZ and CL therapeutic dose. 相似文献
7.
We report the optimization of a sensitive, selective and robust derivatization method using 4-dimethylaminocinnamaldehyde (DMACA) for densitometric determination of (+)-catechin and (−)-epicatechin. The separation of these compounds was achieved by thin-layer chromatography (TLC) on cellulose plates developed with water. With DMACA in HCl, both compounds gave blue bands, while under the same conditions, vanillin produced a fast fading red coloration of bands. Quantitation at 655 nm showed that for both compounds the calibration curve was linear from 2 to 12 ng and polynomial from 2 to 30 ng, and the repeatability of chromatography of 20 ng was 3.5% (RSD, n = 6). The visible limit of detection of both standards was 1 ng, but the densitometric limit of detection was lower (0.2 ng). The optimized DMACA reagent is superior to the more frequently used vanillin reagent and is applicable also for determination of mixtures containing other catechins ((−)-catechin, (−)-epicatechin gallate, (−)-epigallocatechin gallate, procyanidin A2, procyanidin B1 and procyanidin B2). 相似文献
8.
A. Talić S. Ćerimović R. Beigelbeck F. Kohl A. Jachimowicz F. Keplinger 《Procedia Chemistry》2009,1(1):136-139
A novel thermal flow sensor transduction method is presented combining advantages of the calorimetric and the hot-film transduction principle. Four thin-film germanium thermistors are embedded in the silicon-nitride membrane acting as heat sources and as temperature sensors simultaneously. These devices operate in a Wheatstone bridge. The voltage across the bridge as well as the total dissipated power serves as output quantities. Two sensor configurations with different arrangement of the membrane thermistors were examined experimentally. Moreover, we investigated the influence of different layouts on the rise time, the sensitivity, and the usable flow range by means of two-dimensional finite element simulations. 相似文献
9.
Evgenija A. Djurendić Olivera R. Klisurić Mihály Szécsi Marija N. Sakač Suzana S. Jovanović-Šanta Imre Ignáth Vesna V. Kojić Aleksandar M. Oklješa Marina P. Savić Katarina M. Penov-Gaši 《Structural chemistry》2014,25(6):1747-1758
Tetrakis-, tris-, bis-, and mono salicylic acid derivatives 1–4 were synthesized by reaction of methyl 2-hydroxy benzoate (methyl salicylate) with 2,2-bis (hydroxymethyl) propane-1,3-diol (pentaerythritol) in the presence of sodium. Yields of different salicyloyloxy derivatives were changed by varying the molar ratios of reactants. For compounds 2 and 3, X-ray structure analysis was performed, as well as molecular energy minimization, to define their conformation in terms of their energy minima. Comparison of crystal and energy minimized structures for these two compounds (2 and 3) revealed that the intramolecular hydrogen bonds play an important role, stabilizing conformation of the most part of the molecule. The antioxidant activity and cytotoxicity of the synthesized derivatives were evaluated in a series of in vitro tests, as well as 17β-hydroxysteroid dehydrogenase type 2 inhibition potency. Tetrakis salicyloyloxy derivative 1 expressed the highest antioxidant potency, tris salicyloyloxy derivative 2 was the best inhibitor of 17βHSD2 enzyme, while bis salicyloyloxy derivative 3 showed strong cytotoxicity against prostate and breast cancer cells with no cytotoxicity against healthy cells. 相似文献
10.
Variation of the total mean curvature of piecewise smooth surfaces in Euclidean 3-spaces under infinitesimal bending is discussed and reduced to a sum of line integrals of a rotation vector field. 相似文献