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排序方式: 共有164条查询结果,搜索用时 15 毫秒
91.
Victor A Rozentsvet Valery G Kozlov Elza F Ziganshina Natalya P Boreiko Sergei V Kostjuk 《Polymer International》2013,62(5):817-826
The activity of ZnX2‐based initiating systems (X = Cl, Br, I) in the cationic polymerization of isoprene was studied. The highest activity was achieved when co‐initiator (ZnX2) was solubilized in a minimal amount of strongly coordinating solvent such as diethyl ether or acetone and when trichloroacetic acid was used as an initiator. It is shown that the polymerization rate increased in the series ZnI2 < ZnCl2 < ZnBr2. An increase of initiator concentration and temperature also led to an increase of the polymerization rate. The obtained polyisoprenes did not contain high‐molecular‐weight and insoluble fractions and were characterized by low number‐average molecular weight and relatively narrow molecular weight distribution. Unsaturation of polyisoprene decreased with an increase of monomer conversion and reaction temperature. The unsaturated part of the polyisoprene chain possessed predominantly 1,4‐trans microstructure with regular and inverse addition, whereas the 1,2‐ and 3,4‐isomers were present as minor components. It is shown that the synthesized low‐molecular‐weight polyisoprenes are effective plasticizers for rubber compounds in the manufacture of tyres. © 2012 Society of Chemical Industry 相似文献
92.
Immunoassay with multicomponent protein microarrays fabricated by electrospray deposition 总被引:4,自引:0,他引:4
Two new techniques were recently developed in these laboratories for fabrication of protein microarrays: electrospray deposition of dry proteins and covalent linking of proteins from dry deposits to a dextran-grafted surface. Here we apply these techniques to simultaneously fabricate 1200 identical microarrays. Each microarray, 0.6 x 0.6 mm2 in size, consists of 28 different protein antigens and allergens deposited as spots, 30-40 microm in diameter. The ability of the microarrays to detect IgG antibodies in plasma samples from mice immunized with different sets of antigens and IgE antibodies in human plasmas was examined using ELISA. Comparison of the microarray-based ELISAs with standard ELISAs in microtiter plates established that both techniques provided identical responses in 88% of all the antibody/antigen interactions tested. Both techniques showed similar antibody detecting sensitivity defined by the maximum dilution of serum at which a reliable signal distinguishable from the background was obtained. 相似文献
93.
94.
Aleksei B. Sheremetev Valentina O. Kulagina Natalya S. Aleksandrova Dmitrii E. Dmitriev Yurii A. Strelenko Vyacheslav P. Lebedev Yurii N. Matyushin 《Propellants, Explosives, Pyrotechnics》1998,23(3):142-149
The search of the new low-melting high energetic materials, which match the performance of TNAZ and more available, is the barest necessity. The syntheses of several novel zero-hydrogen but nitrogen and oxygen rich high energetic heterocycles, such as bridged nitrofurazans, were undertaken to test the hypothesis that accumulate furazan ring in such molecule could effectively serve in construction of energetically interesting materials. Eight dinitro trifurazans were synthesized and tested. The series of compounds was prepared in three--five stages from the 3,4-diaminofurazan( 10 ). Oxy bridge was formed by utilizing hydroxyfurazans as nucleophiles. Azo bridge was prepared by oxidizing coupling of amino groups with KMnO4 in acid medium. Transformation of azo bridge to azoxy one was accomplished by mixture of(NH4)2S2O8 and oleum. The set of trifurazans represents a new class of low-melting high energetic materials which are among the most potent CxHyNzOw-explosives known. The isomeric diazoxyfurazans,( 28 ),( 29 ), and( 30 ), differ dramatically in their properties. Liquid diazoxy compound( 28 ) has density of 1.8 g/cm3 and is reach a record figure for CxHyNzOw-oil known. 相似文献
95.
Vadim Tseilikman Maria Komelkova Marina V. Kondashevskaya Eugenia Manukhina H. Fred Downey Valerii Chereshnev Margarita Chereshneva Pavel Platkovskii Anna Goryacheva Anton Pashkov Julia Fedotova Olga Tseilikman Natalya Maltseva Olga Cherkasova Charlotte Steenblock Stefan R. Bornstein Barbara Ettrich George P. Chrousos Enrico Ullmann 《International journal of molecular sciences》2021,22(24)
Background: Rats exposed to chronic predator scent stress mimic the phenotype of complex post-traumatic stress disorder (PTSD) in humans, including altered adrenal morphology and function. High- and low-anxiety phenotypes have been described in rats exposed to predator scent stress (PSS). This study aimed to determine whether these high- and low-anxiety phenotypes correlate with changes in adrenal histomorphology and corticosteroid production. Methods: Rats were exposed to PSS for ten days. Thirty days later, the rats’ anxiety index (AI) was assessed with an elevated plus-maze test. Based on differences in AI, the rats were segregated into low- (AI ≤ 0.8, n = 9) and high- (AI > 0.8, n = 10) anxiety phenotypes. Plasma corticosterone (CORT) concentrations were measured by ELISA. Adrenal CORT, desoxyCORT, and 11-dehydroCORT were measured by high-performance liquid chromatography. After staining with hematoxylin and eosin, adrenal histomorphometric changes were evaluated by measuring the thickness of the functional zones of the adrenal cortex. Results: Decreased plasma CORT concentrations, as well as decreased adrenal CORT, desoxyCORT and 11-dehydroCORT concentrations, were observed in high- but not in low-anxiety phenotypes. These decreases were associated with increases in AI. PSS led to a significant decrease in the thickness of the zona fasciculata and an increase in the thickness of the zona intermedia. The increase in the thickness of the zona intermedia was more pronounced in low-anxiety than in high-anxiety rats. A decrease in the adrenal capsule thickness was observed only in low-anxiety rats. The nucleus diameter of cells in the zona fasciculata of high-anxiety rats was significantly smaller than that of control or low-anxiety rats. Conclusion: Phenotype-associated changes in adrenal function and histomorphology were observed in a rat model of complex post-traumatic stress disorder. 相似文献
96.
Giuseppe Federico Amodeo Natalya Krilyuk Evgeny V. Pavlov 《International journal of molecular sciences》2021,22(20)
The c subunit of the ATP synthase is an inner mitochondrial membrane (IMM) protein. Besides its role as the main component of the rotor of the ATP synthase, c subunit from mammalian mitochondria exhibits ion channel activity. In particular, c subunit may be involved in one of the pathways leading to the formation of the permeability transition pore (PTP) during mitochondrial permeability transition (PT), a phenomenon consisting of the permeabilization of the IMM due to high levels of calcium. Our previous study on the synthetic c subunit showed that high concentrations of calcium induce misfolding into cross-β oligomers that form low-conductance channels in model lipid bilayers of about 400 pS. Here, we studied the effect of cyclophilin D (CypD), a mitochondrial chaperone and major regulator of PTP, on the electrophysiological activity of the c subunit to evaluate its role in the functional properties of c subunit. Our study shows that in presence of CypD, c subunit exhibits a larger conductance, up to 4 nS, that could be related to its potential role in mitochondrial toxicity. Further, our results suggest that CypD is necessary for the formation of c subunit induced PTP but may not be an integral part of the pore. 相似文献
97.
Ildar R. Bakhtogarimov Anna V. Kudryavtseva George S. Krasnov Natalya S. Gladysh Vsevolod V. Volodin Alexander A. Kudryavtsev Elizaveta V. Bulavkina Margarita A. Goncharova Veronika S. Ledyaeva Ivan S. Pastukhov Yulia S. Vershinina Anna M. Starkova Anastasiya V. Snezhkina Anastasija I. Shuvalova Vladislav S. Pavlov Dmitry L. Nikiforov-Nikishin Alexey A. Moskalev Zulfiya G. Guvatova 《International journal of molecular sciences》2022,23(5)
98.
Bogatyreva Natalya S.; Finkelstein Alexei V. 《Protein engineering, design & selection : PEDS》2001,14(8):521-523
Funnel-like landscapes are widely used to visualize proteinfolding. It might seem that any funnel-like energy landscapehelps to avoid the `Levinthal paradox', i.e. to avoid samplingthe impossibly large number of conformations for a folding protein.This cunning suggestion, reinforced by beautiful drawings ofthe energy funnels, stimulated some simple models of proteinfolding; one of them [D.J. Bicout and A. Szabo (2000) ProteinSci., 9, 452465] is especially straightforward and instructive.A thorough analysis of this strict funnel model (which doesnot consider a nucleation of phase separation in the courseof folding) shows that it cannot provide a simultaneous explanationfor both major features observed for protein folding: (i) foldingwithin non-astronomical time, and (ii) co-existence of the nativeand the unfolded states during the folding process. On the contrary,the nucleation mechanism of protein folding can account forboth these major features simultaneously. 相似文献
99.
Ontology Evolution: Not the Same as Schema Evolution 总被引:10,自引:1,他引:10
As ontology development becomes a more ubiquitous and collaborative process, ontology versioning and evolution becomes an important area of ontology research. The many similarities between database-schema evolution and ontology evolution will allow us to build on the extensive research in schema evolution. However, there are also important differences between database schemas and ontologies. The differences stem from different usage paradigms, the presence of explicit semantics and different knowledge models. A lot of problems that existed only in theory in database research come to the forefront as practical problems in ontology evolution. These differences have important implications for the development of ontology-evolution frameworks: The traditional distinction between versioning and evolution is not applicable to ontologies. There are several dimensions along which compatibility between versions must be considered. The set of change operations for ontologies is different. We must develop automatic techniques for finding similarities and differences between versions. 相似文献
100.
Victor Sagaradze Valery Shabashov Natalya Kataeva Kirill Kozlov Vadim Arbuzov Sergey Danilov Yury Ustyugov 《Metals and Materials International》2018,24(2):249-254
The deformation-induced dissolution of Ni3Ti intermetallics in the matrix of austenitic alloys of Fe–36Ni–3Ti type was revealed in the course of their cascade-forming neutron irradiation and cold deformation at low temperatures via employment of Mössbauer method. The anomalous deformation-related dissolution of the intermetallics has been explained by the migration of deformation-induced interstitial atoms from the particles into a matrix in the stress field of moving dislocations. When rising the deformation temperature, this process is substituted for by the intermetallics precipitation accelerated by point defects. A calculation of diffusion processes has shown the possibility of the realization of the low-temperature diffusion of interstitial atoms in configurations of the crowdions and dumbbell pairs at 77–173 K. The existence of interstitial atoms in the Fe–36Ni alloy irradiated by electrons or deformed at 77 K was substantiated in the experiments of the electrical resistivity measurements. 相似文献