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71.
Tokareva I Tokarev I Minko S Hutter E Fendler JH 《Chemical communications (Cambridge, England)》2006,(31):3343-3345
An ultrathin novel nanosensor (31.5 +/- 4.1 nm thick in the absence of analytes), employing a molecularly imprinted polymer as a recognition element for cholesterol and gold nanoparticle enhanced transmission surface plasmon resonance spectroscopy for detection, was constructed. 相似文献
72.
Tandem Deprotection–Dimerization–Macrocyclization Route to C2 Symmetric cyclo‐Tetrapeptides
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Khanh Ha Dr. Iryna Lebedyeva Sadra Hamedzadeh Zhiliang Li Ryan Quiñones Girinath G. Pillai Byron Williams Amir Nasajpour Kristin Martin Prof. Dr. Abdullah M. Asiri Prof. Dr. Alan R. Katritzky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4874-4879
Dimerization–macrocyclization has been a long‐standing problem in the cyclization of peptides since, together with the desired cyclic product, many cyclic oligomers and linear polymers may also be formed during the reaction. Therefore, the development of a process that affords the cyclic dimer predominantly is difficult. A novel and versatile strategy for the synthesis of symmetric cyclo‐tetrapeptides by palladium‐promoted tandem deprotection/cyclo‐dimerization from readily available Cbz‐dipeptidoyl benzotriazolides is reported (Cbz=carboxybenzyl). 相似文献
73.
Iryna Pohrelyuk Oleh Tkachuk Roman Proskurnyak 《Central European Journal of Chemistry》2014,12(2):260-265
The corrosion properties of Ti-6Al-4V alloy with oxidized thermodiffusion nitride coatings were investigated in isotonic 0.9% solution of NaCl at temperature of 40°C. It was shown that modification of nitride coatings by oxygen leads to a deterioration of the protective properties of nitrided surface of Ti-6Al-4V alloy. The protective properties of the alloy with nitride coatings modified by oxygen are determined by the composition of formed surface oxynitride film. 相似文献
74.
Maryna V. Murlykina Yana I. Sakhno Sergey M. Desenko Iryna S. Konovalova Oleg V. Shishkin Dmytro A. Sysoiev Maryna N. Kornet Valentin A. Chebanov 《Tetrahedron》2013
Three-component reactions of 5-aminopyrazoles and salicylic aldehydes with pyruvic acids were studied. The method of tuning of the selectivity of the heterocyclizations allowing to change its direction by variation of the reaction parameters was worked out. The treatment involving pyruvic acid can be selectively directed to the formation to either 3-aryl-10,11-dihydro-4,10-methano-pyrazolo[4,3-c][1,5]benzoxazocine-4-carboxylic acids or 3,6-diarylpyrazolo[3,4-b]pyridine-4-carboxylic acids, while the reaction involving arylpyruvic acid leads only to 7-hydroxy-2,5,6-triaryl-4,5,6,7-tetrahydro-pyrazolo[1,5-a]pyrimidine-7-carboxylic acids. Antimicrobial activity of the compounds obtained was also studied: Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) were found sensitive to the substances tested, however, only in the highest concentration. 相似文献
75.
Iryna Antonyshyn Ana M. Barrios Jimnez Olga Sichevych Ulrich Burkhardt Igor Veremchuk Marcus Schmidt Alim Ormeci Ioannis Spanos Andrey Tarasov Detre Teschner Gerardo Algara‐Siller Robert Schlgl Yuri Grin 《Angewandte Chemie (International ed. in English)》2020,59(38):16770-16776
The production of hydrogen via water electrolysis is feasible only if effective and stable catalysts for the oxygen evolution reaction (OER) are available. Intermetallic compounds with well‐defined crystal and electronic structures as well as particular chemical bonding features are suggested here to act as precursors for new composite materials with attractive catalytic properties. Al2Pt combines a characteristic inorganic crystal structure (anti‐fluorite type) and a strongly polar chemical bonding with the advantage of elemental platinum in terms of stability against dissolution under OER conditions. We describe here the unforeseen performance of a surface nanocomposite architecture resulting from the self‐organized transformation of the bulk intermetallic precursor Al2Pt in OER. 相似文献
76.
Zhenzhen Cai Anja Kastell Claire Speiser Iryna Smetanska 《Applied biochemistry and biotechnology》2013,171(2):330-340
The effects of heavy metal ions (Co2+, Ag+, Cd2+) on cell viability and secondary metabolite production, particularly anthocyanins and phenolic acids in Vitis vinifera cell suspension cultures, were investigated. Of these, Co at all three used concentrations (5.0, 25, and 50 μM), Ag, and Cd at low concentration (5.0 μM) were most effective to stimulate the phenolic acid production, increasing the 3-O-glucosyl-resveratrol up to 1.6-fold of the control level (250.5 versus 152.4 μmol/g), 4 h after the treatments. Meanwhile, the elicitors at effective concentrations did not suppress cell growth, while the cell viability maintained. In contrast, Ag and Cd at high concentrations (25 and 50 μM) remarkably reduced the cell viability, decreasing the cell viability up to about 15 % of the control level, 24 h after the treatments. The heavy metal ions did not affect the anthocyanin production. These observations show how, in a single system, different groups of secondary products can show distinct differences in their responses to potential elicitors. The 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, peroxidase activity, medium pH value, and conductivity were only slightly elevated by the heavy metal ions. The results suggest that some of the secondary metabolites production was stimulated by the used elicitors, but there was not a stress response of the cells. 相似文献
77.
Iryna Ryzhkova 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2007,58(2):246-261
We discuss the problem of non-linear oscillations of a clamped thermoelastic plate in a subsonic gas flow. The dynamics of
the plate is described by von Kármán system in the presence of thermal effects. No mechanical damping is assumed. To describe
the influence of the gas flow we apply the linearized theory of potential flows. Our main result states that each weak solution
of the problem considered tends to the set of the stationary points of the problem.
A similar problem was considered in [27], but with rotational inertia accounted for, i.e. with the additional term −αΔutt,α > 0, and the same result on stabilization was obtained. There was introduced the decomposition of the solution such that
the one term tends to zero and the other is compact in special (“local energy”) topology. This decomposition enables us to
prove the main result. But the case of rotational inertia neglected (α = 0) appears more difficult. Low a priori smoothness
of ut in the case α = 0 prevents us to construct such a decomposition. In order to prove additional smoothness of ut we use analyticity of the corresponding thermoelastic semigroup proved in [25].
The isothermal variant of this problem with additional mechanical damping term −εΔut
, ε > 0 was considered in [13] and stabilization to the set of stationary solutions to the problem was proved. The problem,
considered in the present work can also be regarded as an extension of the result of [18] to the case when gas occupies an
unbounded domain. 相似文献
78.
Tetyana A. Shantalii Iryna L. Karpova Kateryna S. Dragan Eleonora G. Privalko Vitaly M. Karaman Valery P. Privalko 《先进技术聚合物》2005,16(5):400-404
Poly(amide imide) (PAI) nanocomposites prepared by the in situ generation of crosslinked organosilicon nanophase (ON) through the sol‐gel process were characterized by wide‐angle and small‐angle X‐ray diffraction, thermogravimetric analysis, dynamic mechanical analysis and kinetics of water uptake. It was concluded that the polymer nanocomposite (PNC) were likely to possess a complex morphology on the nanoscale characterized by co‐existence of two mixed nanophases of different compositions. At low methyl triethoxysilane (MTS) contents the fractal‐like organization of paracrystalline nano‐domains of PAI chain fragments is destroyed by the randomly distributed ON particles, whereas on the increase of MTS content the spatial correlations between ON particles become stronger, giving rise to their own fractal‐like structure. The higher values of small‐angle X‐ray scattering (SAXS) invariant, apparent water diffusivity and limiting water uptake for the PNC compared to the pristine PAI were assumed to reflect the loose inner structures of PAI‐rich and ON‐rich nanophases, respectively. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
79.
Büchel GE Stepanenko IN Hejl M Jakupec MA Keppler BK Arion VB 《Inorganic chemistry》2011,50(16):7690-7697
By controlled Anderson type rearrangement reactions complexes of the general formula trans-[Os(IV)Cl(4)(Hazole)(2)], where Hazole = 1H-pyrazole, 2H-indazole, 1H-imidazole, and 1H-benzimidazole, have been synthesized. Note that 2H-indazole tautomer stabilization in trans-[Os(IV)Cl(4)(2H-indazole)(2)] is unprecedented in coordination chemistry of indazole. The metal ion in these compounds possesses the same coordination environment as ruthenium(III) in (H(2)ind)[Ru(III)Cl(4)(Hind)(2)], where Hind = 1H-indazole, (KP1019), an investigational anticancer drug in phase I clinical trials. These osmium(IV) complexes are appropriate precursors for the synthesis of osmium(III) analogues of KP1019. In addition the formation of an adduct of trans-[Os(IV)Cl(4)(Hpz)(2)] with cucurbit[7]uril is described. The compounds have been comprehensively characterized by elemental analysis, EI and ESI mass spectrometry, spectroscopy (IR, UV-vis, 1D and 2D NMR), cyclic voltammetry, and X-ray crystallography. Their antiproliferative acitivity in the human cancer cell lines CH1 (ovarian carcinoma), A549 (nonsmall cell lung carcinoma), and SW480 (colon carcinoma) is reported. 相似文献
80.
Stepanenko IN Casini A Edafe F Novak MS Arion VB Dyson PJ Jakupec MA Keppler BK 《Inorganic chemistry》2011,50(24):12669-12679
Following our strategy of coupling cyclin-dependent kinase (Cdk) inhibitors with organometallic moieties to improve their physicochemical properties and bioavailability, five organoruthenium complexes (1c-5c) of the general formula [RuCl(η(6)-arene)(L)]Cl have been synthesized in which the arene is 4-formylphenoxyacetyl-η(6)-benzylamide and L is a Cdk inhibitor [3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines (L1-L3) and indolo[3,2-d]benzazepines (L4 and L5)]. All of the compounds were characterized by spectroscopic and analytical methods. Upon prolonged standing (2-3 months) at room temperature, the dimethyl sulfoxide (DMSO) solutions of 1c and 2c(-HCl) afforded residues, which after recrystallization from EtOH and EtOH/H(2)O, respectively, were shown by X-ray diffraction to be cis,cis-[Ru(II)Cl(2)(DMSO)(2)(L1)]·H(2)O and mer-[Ru(II)Cl(DMSO)(3)(L2-H)]·H(2)O. Compound 5c, with a coordinated amidine unit, undergoes E/Z isomerization in solution. The antiproliferative activities and effects on the cell cycle of the new compounds were evaluated. Complexes 1c-5c are moderately cytotoxic to cancer cells (CH1, SW480, A549, A2780, and A2780cisR cell lines). Therefore, in order to improve their antiproliferative effects, as well as their drug targeting and delivery to cancer cells, 1c-5c were conjugated to recombinant human serum albumin, potentially exploiting the so-called "enhanced permeability and retention" effect that results in the accumulation of macromolecules in tumors. Notably, a marked increase in cytotoxicity of the albumin conjugates was observed in all cases. 相似文献