排序方式: 共有85条查询结果,搜索用时 234 毫秒
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Larisa Karpenko-Jereb Edyta Rynkowska Wojciech Kujawski Sarah Lunghammer Joanna Kujawa Stéphane Marais Kateryna Fatyeyeva Corinne Chappey Anne-Marie Kelterer 《Ionics》2016,22(3):357-367
The work is devoted to a computational study of three types of cationic polymeric membranes in Li+-ionic form, in water and methanol environments, at various solvation levels. The studied membranes Nafion, IonClad, and M3 possess the perfluorinated backbone; however, various side chains were terminated with the functional groups of distinctly different ionic strength. The paper discusses the structural features of the membrane-solvent clusters as well as an influence of the side chain nature on the dissociation of the functional groups and the binding energy of the solvent molecules. Additionally, the paper compares the obtained results for Li+-Nafion membrane in water with the results published earlier for H+ and Na+ forms. 相似文献
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Artyushkova K Pylypenko S Olson TS Fulghum JE Atanassov P 《Langmuir : the ACS journal of surfaces and colloids》2008,24(16):9082-9088
Chemical structure and catalytic activity of nonplatinum porphyrin-based electrocatalyst for oxygen reduction is characterized by combination of X-ray photoelectron spectroscopy (XPS) and rotating disk electrode. The goal of the study is to show how modifications in the molecular structure affect catalytic characteristics and how to use these structural modifications in a purposeful manner to increase catalytic activity. Initial correlation of structure to electrochemical performance is achieved through the application of principal component analysis (PCA) to curve-fits of high-resolution XPS spectra combined with results of electrochemical measurements. Furthermore, a predictive model that describes this correlation is build using the combination of genetic algorithm (GA) and multiple linear regression (MLR). Based on structure-to-property correlations, two types of active sites responsible for the catalytic activity, i.e., Co associated with pyropolymer and Co particles covered by oxide layer, are determined, and a dual-site for oxygen reduction on cobalt porphyrins is hypothesized, allowing for designing a catalyst structure with optimal performance characteristics. 相似文献
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Schneider T Artyushkova K Fulghum JE Broadwater L Smith A Lavrentovich OD 《Langmuir : the ACS journal of surfaces and colloids》2005,21(6):2300-2307
We use a layer-by layer electrostatic self-assembly technique to obtain in-plane oriented aggregates of mesogenic dye molecules cast from lyotropic chromonic liquid crystals (LCLCs) on mica substrates. The aqueous solutions of dye used for deposition are in the nematic phase. Atomic force microscopy and X-ray photoelectron spectroscopy of the dried film reveal that the LCLC molecules adsorb at the charged substrate preserving ordered aggregates of elongated shape characteristic of the nematic phase in the aqueous solution. These elongated aggregates of LCLC molecules form films with in-plane orientational order and are compositionally distinct from the substrate. 相似文献
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Kateryna D. Volkova Vladyslava B. Kovalska Mykhaylo Yu. Losytskyy Gertjan Veldhuis G. M. J. Segers-Nolten Olexiy I. Tolmachev Vinod Subramaniam Sergiy M. Yarmoluk 《Journal of fluorescence》2010,20(6):1267-1274
A key feature of Parkinson’s disease is the formation and accumulation of amyloid fibrils of the natively unfolded protein
α-synuclein (ASN) inside neurons. Recently we have proposed novel sensitive monomethinecyanine dye T-284 as fluorescent probe
for quantitative detection of ASN amyloid fibrils. In this study the T-284 dye complex with ASN fibril was characterized by
means of fluorescence anisotropy, atomic force microscopy and time-resolved fluorescence techniques to give further insights
into the mode of dye interaction with amyloid fibrils. The fluorescence anisotropy of T-284 was shown to noticeably increase
upon addition of aggregated proteins indicating on stable dye/amyloid fibril complex formation. AFM imaging of fibrillar wild-type
ASN revealed differences in heights between ASN fibrils alone and in presence of the T-284 dye (6.37 ± 1.0 nm and 8.0 ± 1.1 nm
respectively), that is believed to be caused by embedding of T-284 dye molecules in the “binding channel” running along the
fibril. Fluorescence decay analysis of the T-284 in complexes with fibrillar ASN variants revealed the fluorescence lifetime
values for T-284/fibril complexes to be an order of magnitude higher as compared to the free dye. Also, the fluorescence decay
of free T-284 was bi-exponential, while dye bound to protein yields tri-exponential decay. We suppose that in complexes with
fibrillar ASN variants T-284 dye might exist in different “populations” due to interaction with fibrils in different conformers
and ways. The exact binding mode of T-284 with ASN fibrils needs further studies. Studied parameters of dye/amyloid fibril
complexes are important for the characterization and screening of newly-developed amyloid-sensitive dyes. 相似文献
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On the infinite semigroup of matrix units
there exists no semigroup compact [countably compact] topology.
Any continuous homomorphism from the infinite topological
semigroup of matrix units into a compact topological semigroup is
annihilating. The semigroup of matrix units is algebraically
h-closed in the class of topological inverse semigroups. Some
H-closed minimal semigroup topologies on the infinite semigroup
of matrix units are considered. 相似文献