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91.
The IA database contains 240 structures of known inhibitors of aminoacyl-tRNA synthetases. Structures can be downloaded in different file formats (mol, sdf, smile, png). The search engine offers possibility of searching for the ligands with a given functional group. Additionally, one can search for ligands that act on selected synthetases and from particular references. The data include information which synthetase a given ligand inhibits together with the inhibition constant (IC50) if known. Database is freely available at  相似文献   
92.
Four new compounds: 1,4-dimetoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-dietoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-isopropyloxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene) and 1,4-dietoksy-2,5-bis[2-(5-methylthiophen-2-yl)ethenyl]benzene are synthesized. Three steroisomers ZZ, EZ and EE are isolated from the reaction mixture for the first two of them. Third compound is fully converted to the most stable EE form. Polymerization of all isomers leads to identical polymeric product. Mechanism of polymerization is recognized by using model molecule with methyl substituents blocking α-, α′-sites. All seven stereoisomers have photoluminescent properties. Detailed spectral and electrochemical studies reveal isomerization phenomena during oxidation or at light exposure. Published in Russian in Elektrekhimiya, 2006, Vol. 42, No. 12, pp. 1401–1408. Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes.” October 18–22, 2005, Moscow. The text was submitted by the authors in English.  相似文献   
93.
    
This article the first reports on a fabrication and application of an electrochemical three electrode micro‐set containing: in situ plated lead film on carbon fiber working microelectrode, Ag/AgCl reference electrode and a platinum wire counter electrode placed in one casing for simultaneous Ni(II) and Co(II) traces determination by square wave adsorptive stripping voltammetry (SW AdSV). Ni(II) and Co(II) in forms of their complexes with nioxime were accumulated on the lead film plated on a carbon fibers microelectrode during standard procedure of measurement. Thanks to the fact that measurements were performed in micro‐vessel of a volume of 200 μl small amounts of reagents were used to prepare samples for measurements. In addition, because of the use of microelectrode, sample solutions were not mixed during accumulation step of measurements. This fact creates the possibility of conducting fields analysis. The experimental parameters (composition of the supporting electrolyte, potential and time of accumulation) and possible interference effects were investigated. The linear calibration graphs for Ni(II) and Co(II) were in the range from 2×10?9 to 1×10?7 mol L?1 and from 2×10?10 to 1×10?8 mol L?1 for Ni(II) and Co(II), respectively. The correctness of the proposed method was checked by determining Ni(II) and Co(II) in the certified reference material (SPS‐SW1) with satisfactory results.  相似文献   
94.
    
Using abstract interpolation theory, we study eigenvalue distribution problems for operators on complex symmetric Banach sequence spaces. More precisely, extending two well-known results due to König on the asymptotic eigenvalue distribution of operators on -spaces, we prove an eigenvalue estimate for Riesz operators on -spaces with , which take values in a -concave symmetric Banach sequence space , as well as a dual version, and show that each operator on a -convex symmetric Banach sequence space , which takes values in a -concave symmetric Banach sequence space , is a Riesz operator with a sequence of eigenvalues that forms a multiplier from into . Examples are presented which among others show that the concavity and convexity assumptions are essential.

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95.
The group of 1,4-dialkoxy-2,5-bis[2-(thien-2-yl)ethenyl]benzene stereoisomers was synthesized in which methoxy- and ethoxy-groups were used as alkoxy-substituents. These isomers were characterized as solution species both electrochemically and spectroscopically. As expected, these compounds, having a stilben like structure, are the subject of photoisomerization, which is described and discussed. It is demonstrated how electrochemical process may cause isomerization of the double CC bonds in that group of compounds. An attempt of using electrochemical methods to monitor the process of photoisomerization of these compounds is presented. Mechanism of the oxidatively induced electrochemical isomerization has been proposed and discussed. The electrochemical isomerization mechanism is verified by digital simulation, which allowed estimating basic kinetic parameters of the processes.  相似文献   
96.
97.
The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as OH and ONOO.In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH).We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion.Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.  相似文献   
98.
    
Until recently π‐conjugated organic materials are based mainly on linear systems. Recent years, however, have brought about increasing interest in molecules boasting a dendritic, branched, or star‐shaped architecture. This tendency is a direct result of the ongoing search for materials with progressively better properties. Such compounds, featuring novel, 3D architectures, exhibit a multitude of interesting qualities, making them stand out from well‐known materials. The direction of star‐shaped compound application is determined by whether they are able to form aggregates, π‐stacks. This feature is a source of some astounding properties, coveted in numerous applications. Among this class of compounds high charge mobility, high fluorescence efficiency, and good charge separation are all found. Depending on the structure of the core, the molecule may adopt various types of symmetry. Similarly, the conjugation of orbitals may extend over the whole structure or be interrupted at chosen segments. The number of papers pertaining to star‐shaped oligomers and polymers is ascending with each year, evidencing a growing interest in them. Consequently, this Review focuses particularly on the most recent reports concerning modification of the structure and properties of the aforementioned type of compounds, as well as on the development of devices based on them.

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99.
    
3-Nitro-ω-benzylideneacetophenone ( 1 ) reacts with carbanions containing leaving groups to give addition products to the electrophilic side chain. As a result of conjugated addition and subsequent intramolecular vicarious nucleophilic substitution of hydrogen (VNS) in the nitroaromatic ring of 1 in the position para to the nitro group, 4-cyano-7-nitro-3-phenyl-1,2,3,4-tetrahydronaphthalen-1-one and 4-cyano-7-nitro-3-phenylnaphth-1-ol are obtained. Smooth intramolecular VNS in the position para to the nitro group was observed for 4-chloro-1-(3-nitrophenyl)-3-phenyl-4-(p-tosyl)butanol.  相似文献   
100.
We introduce the generalized twisted \(\Gamma \times \mathbb {T}^{n}\)-equivariant degree with n free parameters, where \(\Gamma \) is a nonabelian finite group, present a computational formulae based on the reduction to \(\mathbb {T}^{n}\)-equivariant maps and reduction of parameters techniques. This twisted equivariant degree can be effectively applied to study Hopf bifurcation with symmetries from relative equilibria. We give an example of such bifurcation in a system of ODEs.  相似文献   
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