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排序方式: 共有204条查询结果,搜索用时 15 毫秒
21.
Beata?A.?Zasońska Helena?Hlídková Eduard?Petrovsky Severyn?Myronovskij Tetyana?Nehrych Nazar?Negrych Mariya?Shorobura Volodymyr?Antonyuk Rostyslav?Stoika Yuriy?Kit Daniel?HorákEmail authorView authors OrcID profile 《Mikrochimica acta》2018,185(5):262
Monodisperse nonmagnetic macroporous poly(glycidyl methacrylate) (PGMA) microspheres were synthesized by multistep swelling polymerization of glycidyl methacrylate, ethylene dimethacrylate and 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA). This was followed (a) by ammonolysis to modify the microspheres with amino groups, and (b) by incorporation of iron oxide (γ-Fe2O3) into the pores to render the particles magnetic. The resulting porous and magnetic microspheres were characterized by scanning and transmission electron microscopy (SEM and TEM), atomic absorption and Fourier transform infrared spectroscopy (AAS and FTIR), elemental analysis, vibrating magnetometry, mercury porosimetry and Brunauer-Emmett-Teller adsorption/desorption isotherms. The microspheres are meso- and macroporous, typically 5 μm in diameter, contain 0.9 mM · g?1 of amino groups and 14 wt.% of iron according to elemental analysis and AAS, respectively. The particles were conjugated to p46/Myo1C protein, a potential biomarker of autoimmune diseases, to isolate specific autoantibodies in the blood of patients suffering from multiple sclerosis (MS). The p46/Myo1C loaded microspheres are shown to enable the preconcentration of minute quantities of specific immunoglobulins prior to their quantification via SDS-PAGE. The immunoglobulin M (IgM) with affinity to Myo1C was detected in MS patients. 相似文献
22.
Pereira-Rodrigues N Cofré R Zagal JH Bedioui F 《Bioelectrochemistry (Amsterdam, Netherlands)》2007,70(1):147-154
Modified electrodes coated by adsorbed cobalt phthalocyanines are known to show substantial electrocatalytic activity for the electro-oxidation of several thiols in alkaline aqueous solution. In this context, we explore in this study the electrocatalytic activity of adsorbed cobalt phthalocyanine (CoPc) on ordinary pyrolytic graphite electrode for the oxidation of reduced L-glutathione GSH and the reduction of its disulfide GSSG at physiological pH. To do so, cyclic and rotating disk voltammetries were performed and the amperometric results show that a stable electrochemical sensing material, with good reproducibility and sensitivity (in accordance with the concentrations of GSH expected in biological media), can be easily achieved. This opens the way for the design of an electrochemical sensor able to detect these two analytes in biologically relevant experimental conditions (in terms of pH). 相似文献
23.
Nazar Pavlyuk Grygoriy Dmytriv Alina Bondaruk Wojciech Ciesielski Volodymyr Pavlyuk 《Acta Crystallographica. Section C, Structural Chemistry》2024,80(5):159-165
The ternary germanide Mg5.57Ni16Ge7.43 (cubic, space group Fmm, cF116) belongs to the structural family based on the Th6Mn23-type. The Ge1 and Ge2 atoms fully occupy the 4a (mm symmetry) and 24d (m.mm) sites, respectively. The Ni1 and Ni2 atoms both fully occupy two 32f sites (.3m symmetry). The Mg/Ge statistical mixture occupies the 24e site with 4m.m symmetry. The structure of the title compound contains a three-core-shell cluster. At (0,0,0), there is a Ge1 atom which is surrounded by eight Ni atoms at the vertices of a cube and consequently six Mg atoms at the vertices of an octahedron. These surrounded eight Ni and six Mg atoms form a [Ge1Ni8(Mg/Ge)6] rhombic dodecahedron with a coordination number of 14. The [GeNi8(Mg/Ge)6] rhombic dodecahedron is encapsulated within the [Ni24] rhombicuboctahedron, which is again encapsulated within an [Ni32(Mg/Ge)24] pentacontatetrahedron; thus, the three-core-shell cluster [GeNi8(Mg/Ge)6@Ni24@Ni32(Mg/Ge)24] results. The pentacontatetrahedron is a new representative of Pavlyuk's polyhedra group based on pentagonal, tetragonal and trigonal faces. The dominance of the metallic type of bonding between atoms in the Mg5.57Ni16Ge7.43 structure is confirmed by the results of the electronic structure calculations. The hydrogen sorption capacity of this intermetallic at 570 K reaches 0.70 wt% H2. 相似文献
24.
25.
The integrated forms of the Michaelis-Menten equation assuming variable substrate (depletion) or constant substrate concentration
were used to study the effect of the simultaneous presence of two exoglucanase Cel7A inhibitors (cellobiose and ethanol) on
the kinetics of cellulose hydrolysis. The kinetic parameters obtained, assuming constant substrate (K
m
=21 mM, K
ic
=0.035 mM; K
icl
=1.5×1015mM; k
cat=12 h−1) or assuming variable substrate (K
m
=16 mM, K
ic
=0.037 mM; K
icl
=5.8×1014 mM; k
cat=9 h−1), showed a good similarity between these two alternative methodologies and pointed out that bothethanol and cellobiose are
competitive inhibitors. Nevertheless, ethanol is a very weak inhibitor, as shown by the large value estimated for the kinetic
constant K
icl
. In addition, assuming different concentrations of initial accessible substrate present in the reaction, both inhibition
and velocity constants are at the same order of magnitude, which is consistent with the obtained values. The possibility of
using this kind of methodology to determine kinetic constants in general kinetic studies is discussed, and several integrated
equations of different Michaelis-Menten kinetic models are presented. Also examined is the possibility of determining inhibition
constants without knowledge of the true accessible substrate concentration. 相似文献
26.
Kim A Black R Hyun YJ Nazar LF Prouzet E 《Chemical communications (Cambridge, England)》2012,48(36):4335-4337
Monolithic porous silica and carbon structures have been obtained by the synthesis of silica inside the aqueous phase of a sponge-like Swollen Liquid Crystal, and the parallel preparation of carbon replica. 相似文献
27.
28.
Nazar Trotsko Jakub Krl Agata Siwek Monika Wujec Urszula Kosikowska Anna Malm 《Heteroatom Chemistry》2012,23(1):117-121
By the reaction of hydrazides of 4‐(4‐halogenophenyl)‐4H‐1,2,4‐triazol‐3‐yl‐sulfanyl acetic acid with isothiocyanate, 1‐acyl‐4‐substituted thiosemicarbazide derivatives ( 7–19 ) were obtained. The cyclization of compounds ( 7–19 ) in the presence of 2% NaOH led to the formation of compounds ( 20–26 ) containing two 1,2,4‐triazole rings connected by a methylenesulfanyl group. The new compounds were tested for their in vitro antimicrobial activity. Some of the tested compounds ( 9, 12, 18, 21, 22 ) showed activity against the reference strains of Gram‐positive bacteria with the MIC (minimal inhibitory concentration) = 125 to >1000 μg/mL. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:117–121, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20758 相似文献
29.
The steady mixed convection boundary-layer flow over a vertical impermeable surface in a porous medium saturated with water
close to its maximum density is considered for uniform wall temperature and outer flow. The problem can be reduced to similarity
form and the resulting equations are examined in terms of a mixed convection parameter λ and a parameter δ which measures
the difference between the ambient temperature and the temperature at the maximum density. Both assisting (λ > 0) and opposing
flows (λ < 0) are considered. A value δ0 is found for which there are dual solutions for a range λc < λ < 0 of λ (the value of λc dependent on δ) and single solutions for all λ ≥ 0. Another value of δ1 of δ, with δ1 > δ0, is found for which there are dual solutions for a range 0 < λ < λc of positive values of λ, with solutions for all λ≤ 0. There is also a range δ0 < δ < δ1 where there are solutions only for a finite range of λ, with critical points at both positive and negative values of λ, thus
putting a finite limit on the range of existence of solutions. 相似文献
30.
The problem of steady laminar mixed convection boundary layer flow of an incompressible viscous fluid along vertical moving
thin needles with variable heat flux for both assisting and opposing flow cases is theoretically considered in this paper.
The governing boundary layer equations are first transformed into non-dimensional forms. The curvature effects are incorporated
into the analysis whereas the pressure variation in the axial direction has been neglected. These equations are then transformed
into similarity equations using the similarity variables, which are solved numerically using an implicit finite-difference
scheme known as the Keller-box method. The solutions are obtained for a blunt-nosed needle (m = 0). Numerical calculations are carried out for various values of the dimensionless parameters of the problem, which include
the mixed convection parameter λ, the Prandtl number Pr and the parameter a representing the needle size. It is shown from the numerical results that the skin friction coefficient, the surface (wall)
temperature and the velocity and temperature profiles are significantly influenced by these parameters. The results are presented
in graphical form and are discussed in detail. 相似文献