Solvent effects in the catalytic hydrotreament of haloaromatics over Pd/Al2O3 in water+organic mixtures

Solvent effects have been studied for the liquid phase (atmospheric pressure, T=303 K) hydrodehalogenation (HDH) of a range of haloarenes in methanol, THF, water+methanol and water+THF promoted by Pd/Al₂O₃. The catalyst has been characterized in terms of temperature programmed reduction, XRD, TEM, BET and pore volume measurements: the active Pd phase is present as nano-scale particles (<1–6 nm, surface area weighted mean diameter=2.4 nm). In the absence of transport limitations, catalyst deactivation and secondary reactions, the following sequence of increasing dehalogenation rate has been established: dichlorophenol(s)<monochlorophenol(s)<dibromophenol<monobromophenol(s). This is consistent with an electrophilic mechanism involving an arenium intermediate. The hydrogenolytic cleavage of C–Br bond(s) is promoted to a greater extent (relative to C–Cl) due to the lower associated bond dissociation energy while the presence of a second halogen substituent has a deactivating effect. Higher initial HDH rates were observed with increasing water content in the solvent mixture and this is principally related to an increase in the dielectric constant of the medium; HDH rate showed a lesser dependence on molar volume. We link the HDH activity dependency on dielectric constant to the capacity of the solvent to stabilize the arenium intermediate. In contrast, reaction selectivity was unaffected by variations in solvent composition, suggesting that each step in the reaction pathway (stepwise or concerted dehalogenation) is influenced to the same extent. Higher HDH rate with increasing solvent dielectric constant and selectivity invariance with solvent composition also extended to the HDH of chlorobenzenes.     

One‐ and two‐phase isochoric heat capacity measurements of aqueous solution of nacl near the critical point of pure water

Isochoric heat capacities of H₂O+NaCl solutions (0.0031 and 0.0063 mole fraction of NaCl) were measured with a high temperature and high pressure adiabatic calorimeter near the sub‐critical and near the supercritical point of pure water. Temperatures ranged from 361 to 677 K. Measurements were made at six densities, namely: 367.07 and 485.59 kg·m^?3 for x = 0.0031 mol fraction of NaCl and 388.65, 560.03, 607.05, and 973.70 kg·m^?3 for x = 0.0063 mol fraction of NaCl. Measurements were conducted in the two‐and one‐phase regions including near phase transition temperatures T_S(ρ). The phase transition temperatures T_S(ρ) and saturated isochoric heat capacity values C_VX have been determined for each isochore. The uncertainty in heat capacity measurements is estimated to be 3.5% to 4.5% near the phase transition and critical points. Present and previous results of heat capacity measurements were compared with predictions from the crossover (CREOS) and Pitzer—Tanger–Hovey equations of state (PTH EOS). Our previous heat capacity measurements were found to deviate systematically from crossover‐model predictions. The present results show good agreement with the crossover model for the composition x = 0.0031 mol fraction.     

Cross-informant symptoms from CBCL, TRF, and YSR: Trait and method variance in a normative sample of Russian youths.

A large community-based sample of Russian youths (n = 841, age M = 13.17 years, SD = 2.51) was assessed with the Child Behavior Checklist (mothers and fathers separately), Teacher's Report Form, and Youth Self-Report. The multiple indicator-version of the correlated trait-correlated method minus one, or CT-C(M ? 1), model was applied to analyze (a) the convergent and divergent validity of these instruments in Russia, (b) the degree of trait-specificity of rater biases, and (c) potential predictors of rater-specific effects. As expected, based on the published results from different countries and in different languages, the convergent validity of the instruments was rather high between mother and father reports, but rather low for parent, teacher, and self-reports. For self- and teacher reports, rater-specific effects were related to age and gender of the children for some traits. These results, once again, attest to the importance of incorporating information from multiple observers when psychopathological traits are evaluated in children and adolescents. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Phosphoproteomics and Lung Cancer Research

Massive evidence suggests that genetic abnormalities contribute to the development of lung cancer. These molecular abnormalities may serve as diagnostic, prognostic and predictive biomarkers for this deadly disease. It is imperative to search these biomarkers in different tumorigenesis pathways so as to provide the most appropriate therapy for each individual patient with lung malignancy. Phosphoproteomics is a promising technology for the identification of biomarkers and novel therapeutic targets for cancer. Thousands of proteins interact via physical and chemical association. Moreover, some proteins can covalently modify other proteins post-translationally. These post-translational modifications ultimately give rise to the emergent functions of cells in sequence, space and time. Phosphoproteomics clinical researches imply the comprehensive analysis of the proteins that are expressed in cells or tissues and can be employed at different stages. In addition, understanding the functions of phosphorylated proteins requires the study of proteomes as linked systems rather than collections of individual protein molecules. In fact, proteomics approaches coupled with affinity chromatography strategies followed by mass spectrometry have been used to elucidate relevant biological questions. This article will discuss the relevant clues of post-translational modifications, phosphorylated proteins, and useful proteomics approaches to identify molecular cancer signatures. The recent progress in phosphoproteomics research in lung cancer will be also discussed.     

SRPassing Co-translational Targeting: The Role of the Signal Recognition Particle in Protein Targeting and mRNA Protection

Signal recognition particle (SRP) is an RNA and protein complex that exists in all domains of life. It consists of one protein and one noncoding RNA in some bacteria. It is more complex in eukaryotes and consists of six proteins and one noncoding RNA in mammals. In the eukaryotic cytoplasm, SRP co-translationally targets proteins to the endoplasmic reticulum and prevents misfolding and aggregation of the secretory proteins in the cytoplasm. It was demonstrated recently that SRP also possesses an earlier unknown function, the protection of mRNAs of secretory proteins from degradation. In this review, we analyze the progress in studies of SRPs from different organisms, SRP biogenesis, its structure, and function in protein targeting and mRNA protection.     

Effects of Aqueous Dispersions of C60, C70 and Gd@C82 Fullerenes on Genes Involved in Oxidative Stress and Anti-Inflammatory Pathways

Background: Fullerenes and metallofullerenes can be considered promising nanopharmaceuticals themselves and as a basis for chemical modification. As reactive oxygen species homeostasis plays a vital role in cells, the study of their effect on genes involved in oxidative stress and anti-inflammatory responses are of particular importance. Methods: Human fetal lung fibroblasts were incubated with aqueous dispersions of C₆₀, C₇₀, and Gd@C₈₂ in concentrations of 5 nM and 1.5 µM for 1, 3, 24, and 72 h. Cell viability, intracellular ROS, NOX4, NFκB, PRAR-γ, NRF2, heme oxygenase 1, and NAD(P)H quinone dehydrogenase 1 expression have been studied. Results & conclusion: The aqueous dispersions of C₆₀, C₇₀, and Gd@C₈₂ fullerenes are active participants in reactive oxygen species (ROS) homeostasis. Low and high concentrations of aqueous fullerene dispersions (AFD) have similar effects. C₇₀ was the most inert substance, C₆₀ was the most active substance. All AFDs have both “prooxidant” and “antioxidant” effects but with a different balance. Gd@C₈₂ was a substance with more pronounced antioxidant and anti-inflammatory properties, while C₇₀ had more pronounced “prooxidant” properties.     

Analysis of cyclitols in different Quercus species by gas chromatography–mass spectrometry

BACKGROUND: The carbohydrate profile of some woods used for aging wines and spirits has been recently studied using a pressurized liquid extraction method, the main differences found being related to cyclitol content. The aim of this study was to perform a detailed study of these compounds in woods of different Quercus species in order to identify two unknown compounds which appeared in the extracts and to verify whether the obtained profile was homogeneous for other Quercus species. RESULTS: Besides the known monosaccharides and five cyclitols previously described, three deoxy‐inositols (epi‐, vibo‐ and scyllo‐quercitol) were identified. The presence of these eight cyclitols was confirmed in all subgenera and species of Quercus analyzed, allowing a characteristic cyclitol profile. CONCLUSIONS: Three deoxy‐inositols (quercitols) have been identified in the carbohydrate profile of oak wood. All examined Quercus species displayed a common profile consisting of four inositols and four quercitols, which represent a good dataset for characterization of this genus. Copyright © 2010 Society of Chemical Industry     

Electromechanical self-oscillations of carbon nanotube field emitter

We report the observation of the electromechanical self-oscillations excited in a vacuum diode with a field emission cathode made of single-wall carbon nanotubes. The mechanical oscillations of the cathode accompanied by the periodic variations of the emission current intensity have been observed under the action of a constant voltage applied between the cathode and the anode of the diode. An empirical model of the phenomenon is proposed. It provides a qualitative agreement of the experimental results and the theoretical predictions. The modeling assuming a common behavior of the electromechanical systems with nano-sized mechanically flexible field emitters has been performed. It has demonstrated a dependence of the oscillation frequency value on the geometrical size of flexible emitters and on the value of voltage applied. This phenomenon opens a way for generation of the high frequency electromagnetic waves by using the electromechanical systems with emitters of nanometer size.     

Structure and Functionality of Whey Protein Concentrate-Based Products with Different Water Contents

Properties of different heated mixtures of whey protein concentrate, starch, gelatin, and sucrose with different water contents were studied. The water activity of samples was determined. The structural properties were analyzed by confocal laser scanning microscopy, solubility assays in different extraction solutions, polyacrylamide gel electrophoresis, and differential scanning calorimetry. Color, texture, and water-holding capacity of samples were also determined. Results show that a certain water content it is needed to form a structure with solid characteristics in these mixtures. The temperature for starch gelatinization is lower than the temperature for whey proteins denaturation, but when sucrose is present, whey proteins are denatured, before the gelatinization of starch. Sucrose is major contributor to the adhesiveness of the samples and to the decrease of their water activity. Also, sucrose decreases the firmness and cohesiveness of the samples. The main component that contributes to the browning of the samples during the heat treatment is whey protein concentrate, whereas starch is the main component responsible for the water-holding capacity in these samples. Gelatin does not modify appreciably the properties of the mixtures in the proportion used in these assays.