Effect of single-walled carbon nanotubes on the structural,physical, and mechanical properties of rat glial cell surface

Journal of Nanoparticle Research - Benefited from their broad-spectrum antimicrobial property, silver nanoparticles (AgNPs) have been widely used in various daily life and medical products....     

Activity of tungstate catalysts in the synthesis of metylmercaptane from methanol and hydrogen sulfide

Catalysis obtained by impregnation of Al₂O₃ with solutions of hepta-, dodeca-, meta- and normal alkaline metal tungstates showed approximately the same activity. Most selective towards methylmercaptane were catalysts with an alkaline metal to tungsten atomic ratio equal to 21.

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, Al₂O₃ -, -, -, . , : 21.

     

Kinetic study of asymmetric hydrogenation of methyl levulinate using the (COD)Ru(2-methylallyl)2–BINAP–HCl catalytic system

The kinetics of asymmetric hydrogenation of methyl levulinate in the presence of the (COD)Ru(2-methylallyl)₂–BINAP–HCl catalytic system was studied. The kinetic order in H₂, as well as in the catalyst, was found to be equal to 1, whereas the kinetic order for the substrate and HCl falled from 1 to 0 with their increasing starting concentration. The kinetic and ³¹P NMR data testify that the mechanism of the reaction under consideration, most likely, involves the hydride transfer to the protonated substrate in the dinuclear ruthenium complex as the rate-limiting step of the catalytic cycle.     

Black holes in models with noncompact extra dimensions

We have investigated the equations of geodesics for the black hole solution suggested in [1] in the Randall-Sundrum model with one brane. Being a generalization of the Schwarzschild metric, this solution has a structure like the Reissner-Nordström one, with the “tidal charge” replacing the electric charge. Following our investigation of the behavior of geodesics, we have shown that this solution is consistent with observational data, without predicting the appearance of any fundamentally new effects. A more accurate constraint on the tidal charge is obtained by analyzing circular orbits.     

Spin-glass, antiferromagnetism and kondo behavior in Ce2Au1−x Co x Si3 alloys

Recently, the solid solution Ce₂Au_{1− x Co} xSi₃ has been shown to exhibit many magnetic anomalies associated with the competition between magnetic ordering and the Kondo effect. Here we report high pressure electrical resistivity of Ce₂AuSi₃, ac susceptibility (X) and magnetoresistance of various alloys of this solid solution in order to gain better knowledge of the magnetism of these alloys. High pressure resistivity behavior is consistent with the proposal that Ce₂AuSi₃ lies at the left-hand side of the maximum in Doniach’s magnetic phase diagram. The ac X data reveal that there are in fact two magnetic transitions, one at 2 K and the other at 3 K for this compound, both of which are spin-glass-like. However, as the Co concentration is increased, antiferromagnetism is stabilized for intermediate compositions before attaining non-magnetism for the Co end member.     

Label‐free cervicovaginal fluid proteome profiling reflects the cervix neoplastic transformation

Cervicovaginal fluid (CVF) is a valuable source of clinical information about the female reproductive tract in both nonpregnant and pregnant women. The aim of this study is to specify the CVF proteome at different stages of cervix neoplastic transformation by label‐free quantitation approach based on liquid chromatography tandem mass spectrometry (LC‐MS/MS) method. The proteome composition of CVF from 40 women of reproductive age with human papillomavirus (HPV)‐associated cervix neoplastic transformation (low‐grade squamous intraepithelial lesion [LSIL], high‐grade squamous intraepithelial lesion [HSIL], and CANCER) was investigated. Hierarchical clustering and principal component analysis (PCA) of the proteomic data obtained by a label‐free quantitation approach show the distribution of the sample set between four major clusters (no intraepithelial lesion or malignancy [NILM], LSIL, HSIL and CANCER) depending on the form of cervical lesion. Multisample ANOVA with subsequent Welch's t test resulted in 117 that changed significantly across the four clinical stages, including 27 proteins significantly changed in cervical cancer. Some of them were indicated as promising biomarkers previously (ACTN4, VTN, ANXA1, CAP1, ANXA2, and MUC5B). CVF proteomic data from the discovery stage were analyzed by the partial least squares‐discriminant analysis (PLS‐DA) method to build a statistical model, allowing to differentiate severe dysplasia (HSIL and CANCER) from the mild/normal stage (NILM and LSIL), and receiver operating characteristic (ROC) area under the curve (AUC) were obtained on an independent set of 33 samples. The sensitivity of the model was 77%, and the specificity was 94%; AUC was equal to 0.87. CVF proteome proved to be reflect the stage of cervical epithelium neoplastic process.     

Palladium-catalyzed diastereoselective hydrogenation of N-substituted 3-methyleneisoindolin-1-ones

An asymmetric synthesis of chiral N-substituted 3-methylisoindolin-1-ones was performed using the Pd⁰-catalyzed diastereoselective hydrogenation of their 3-methylene-substituted precursors, that has not been investigated earlier. The highest diastereoselectivity (67% de) was achieved when the hydrogenation was carried out in methanol mediated by a palladium catalyst (Pd/C) modified with cinchonidine.     

Thermo-mechanical properties of the cell surface assessed by atomic force microscopy

Atomic force microscopy (AFM) in lateral force mode was applied to assess the microscale thermo-mechanical (frictional) properties of the air-dried cell surface in the wide temperature range (288-363K/15-90°C). AFM-investigated cell surface layer can be represented as a biocomposite composed of several layers including the glycocalyx, the membrane and the intercellular layer containing membrane (cortical) cytoskeleton. The cells with two different cytoskeleton structures, erythrocytes and thymocytes, were studied. Above a certain temperature (T(g)), the significant change in friction force with temperature was revealed for the both cell types whereas there was no similar change in their topography parameters. The experimentally determined value T(g) for erythrocyte samples was lower than that for thymocyte ones. Treating living cells with the cross-linking agent, glutaraldehyde, led to the weakening of the temperature dependence of air-dried cell surface frictional properties in the studied temperature range. Addition of oxidizing agent, peroxynitrite, to living cell suspensions changed the temperature dependence of air-dried cell surface frictional properties depending on cell type and peroxynitrite concentration. The obtained data indicate that the study of thermo-mechanical properties of air-dried cells with AFM in lateral force mode provides expanded information on the structural characteristics of the living cell surface layer, and sets the stage for the development of AFM-based method (with using a lateral force mode) for the cell pathology diagnostics.