A new route for the synthesis of CuIn0.5Ga0.5Se2 powder for solar cell applications

In this paper, a new and simple method is described that does not use an autoclave to synthesize copper indium gallium diselenide (CuIn_0.5Ga_0.5Se₂) particles from the constituent elements. The process also does not require a post-synthesis selenization step. A solvo-thermal route is followed in which the constituent element powders are dissolved and made to react in a solvent such as ethylenediamine (ED), or triethylenetetramine (TETA). Crystal structure, morphology, composition, and particle size distribution of prepared particles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and dynamic light scattering (DLS), respectively. The band gap energies of the prepared particles were determined using an UV-VIS-NIR spectrophotometer. The results indicate that the solvent temperature and the synthesis time significantly affect the formation of single-phase CuIn_0.5Ga_0.5Se₂ and the crystallinity of the particles. Further, the measured band gap energy for the prepared particles is close to that of the bulk material. For example, the single-phase plate-like CuIn_0.5Ga_0.5Se₂ particles with an average particle size of 413.9 nm which can be successfully synthesized at a temperature of 250 °C in 15 h, have a band gap energy of 1.15 eV.     

Metabolomics Analyses Reveal Metabolites Affected by Plant Growth-Promoting Endophytic Bacteria in Roots of the Halophyte Mesembryanthemum crystallinum

Mesembryanthemum crystallinum L. (common ice plant) is an edible halophyte. However, if ice plants are used to phytoremediate salinity soil, there are problems of slow initial growth, and a long period before active NaCl uptake occurs under higher salinity conditions. Application of endophytic bacteria may improve the problem, but there remain gaps in our understanding of how endophytic bacteria affect the growth and the biochemical and physiological characteristics of ice plants. The aims of this study were to identify growth-promoting endophytic bacteria from the roots of ice plants and to document the metabolomic response of ice plants after application of selected endophytic bacteria. Two plant growth-promoting endophytic bacteria were selected on the basis of their ability to promote ice plant growth. The two strains putatively identified as Microbacterium spp. and Streptomyces spp. significantly promoted ice plant growth, at 2-times and 2.5-times, respectively, compared with the control and also affected the metabolome of ice plants. The strain of Microbacterium spp. resulted in increased contents of metabolites related to the tricarboxylic acid cycle and photosynthesis. The effects of salt stress were alleviated in ice plants inoculated with the endobacterial strains, compared with uninoculated plants. A deeper understanding of the complex interplay among plant metabolites will be useful for developing microbe-assisted soil phytoremediation strategies, using Mesembryanthemum species.     

Synthesis,Molecular Docking and Biological Characterization of Pyrazine Linked 2-Aminobenzamides as New Class I Selective Histone Deacetylase (HDAC) Inhibitors with Anti-Leukemic Activity

Class I histone deacetylases (HDACs) are key regulators of cell proliferation and they are frequently dysregulated in cancer cells. We report here the synthesis of a novel series of class-I selective HDAC inhibitors (HDACi) containing a 2-aminobenzamide moiety as a zinc-binding group connected with a central (piperazin-1-yl)pyrazine or (piperazin-1-yl)pyrimidine moiety. Some of the compounds were additionally substituted with an aromatic capping group. Compounds were tested in vitro against human HDAC1, 2, 3, and 8 enzymes and compared to reference class I HDACi (Entinostat (MS-275), Mocetinostat, CI994 and RGFP-966). The most promising compounds were found to be highly selective against HDAC1, 2 and 3 over the remaining HDAC subtypes from other classes. Molecular docking studies and MD simulations were performed to rationalize the in vitro data and to deduce a complete structure activity relationship (SAR) analysis of this novel series of class-I HDACi. The most potent compounds, including 19f, which blocks HDAC1, HDAC2, and HDAC3, as well as the selective HDAC1/HDAC2 inhibitors 21a and 29b, were selected for further cellular testing against human acute myeloid leukemia (AML) and erythroleukemic cancer (HEL) cells, taking into consideration their low toxicity against human embryonic HEK293 cells. We found that 19f is superior to the clinically tested class-I HDACi Entinostat (MS-275). Thus, 19f is a new and specific HDACi with the potential to eliminate blood cancer cells of various origins.     

Supercritical Carbon Dioxide Fractionation of Anhydrous Milk Fat

Supercritical carbon dioxide was used to fractionate anhydrous milk fat. Six fractions were produced at 40, 50 and 60 °C using pressure values of 10, 20, 25, 30, 33 and 36 MPa. The fractions were analyzed for fatty acids, thermal behavior, iodine and color values. Composition and yield of fatty acid methyl esters were evaluated at different fractionation conditions in relation to the original milk fat values. Short chain fatty acids (C₄–C₈), medium chain fatty acids (C₁₀–C₁₄) and total saturated fatty acids were decreased from fraction obtained in the order of 10–36 MPa, while long chain fatty acids (C₁₆–C_18:2) and total unsaturated fatty acids were increased. Fractions obtained in the raffinate stage of the fractionation exhibited higher melting behavior that obtained at the low CO₂ pressures. The higher iodine value of raffinate fraction indicated that fraction was richer in oleic acid. Fractions produced at low pressures had lower melting behavior than those obtained at high pressures. Yellowness Index and b* values increased in raffinate fraction due to concentration of carotenoids.     

Synthesis and characterization of boron doped bismuth–calcium–cobalt oxide nanoceramic powders via polymeric precursor technique

In this study, boron doped calcium stabilized bismuth cobalt oxide nanocrystalline ceramic powders were successfully prepared from aqueous boric acid containing calcium–bismuth–cobalt acetate/poly(vinyl alcohol) hybrid precursor polymer solutions. Then, obtained ceramic powders were characterized via FT-IR, XRD, and SEM techniques. According to X-ray results, fcc and bcc phases coexist in the samples of the nanocrystalline ceramic powders. fcc peaks became sharper and bcc peak decreased with increasing boron content. Structural parameters for face centered cubic structure were calculated using the Scherrer equation. Moreover, dislocation densities and microstrain values were calculated for the nanocrystalline powder samples.     

Design of a methane processing system producing high-purity hydrogen

Design of a catalytic methane-to-proton exchange membrane fuel cell (PEMFC) grade hydrogen conversion system consisting of indirect partial oxidation (IPOX), water–gas shift (WGS) and preferential carbon monoxide oxidation (PROX) reactors is investigated using modeling and simulation techniques. Steady-state simulation, design and sizing of reactors, which are considered to be packed-bed tubular type, are carried out for twelve different feed composition and PEMFC power output configurations, namely (CH₄/O₂, H₂O/CH₄) = (2.24, 1.17), (1.89, 1.56) and (10, 50, 100, 500, 1000, 1500 W). For every configuration, material balance calculations are executed to obtain the flow rates of each species at each stream. These results are then used as boundary conditions to estimate the catalyst weights in each reactor via simulations conducted using a one-dimensional pseudo-homogeneous reactor model. Finally, reactor and catalyst particle dimensions are estimated by considering pressure drop and a set of criteria to quantify interfacial heat and intraparticle mass transfer resistances and fluid flow characteristics in packed beds. The total catalyst quantity is found to increase almost linearly with the PEMFC power output at both feed compositions. Total system volume, excluding piping, pumping, heat exchange and other peripheral units, is estimated to be 6.3, 40.3, 83.4, 488, 985 and 1527 cm³ for 10, 50, 100, 500, 1000 and 1500 W operations, respectively. WGS unit requires the highest space corresponding to ca. 50% of the total reactor volume, followed by IPOX (ca. 39%) and PROX (ca. 11%) reactors. Power densities, based on the weight and volume of the reactors are estimated as 1.1 kW/kg and 1.2 kW/l, respectively.     

Mayo cognitive factors scales: Derivation of a short battery and norms for factor scores.

G. E. Smith et al (see PA, Vol 80:4129 and 24183) confirmed that 5 factors underlie the covariance structure of a core battery of the Wechsler Adult Intelligence Scale—Revised (WAIS—R), Wechsler Memory Scale—Revised (WMS—R), and Auditory Verbal Learning Test administered to the Mayo's Older Americans Normative Studies sample and to an independent clinical sample. In the present study, full factor scores generated by this 5-factor model were used as criterion variables in the development of a short battery. It was determined that 16 of the 24 subtests were sufficient to explain substantial variance in the 5 factor scores. However, 1 additional immediate memory subtest must be administered as a prelude to a delayed recall test. Thus, a collection of 17 subtests are offered as a short battery for older persons. Norms for the calculation of Mayo Cognitive Factor Scales scores are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A two-phase level tracking method

Interfacial closure models in most two-fluid system codes for reactor safety are usually tied to the flow regime map through the mean void fraction in a computational cell. When a void fraction discontinuity exists in a computational volume, neither heat nor momentum exchange at the phase interface for this particular cell can be properly represented in finite-difference equations governing the fluid flow. Moreover, finite-difference methods with a fixed, Eulerian grid will inaccurately predict the cell-to-cell convection of mass, momentum and energy when the mean cell macroscopic variables are convected from the cell containing the void fraction front. The adequate modeling of two-phase mixture levels requires the knowledge of front position and void fractions above and below the front. In order to obtain such information, an efficient and simple tracking method was implemented in the TRAC-BWR code (released April 1984). We have tested this method with a simple problem involving a moving two-phase air/water mixture level. The results revealed inconsistencies in the behavior of velocities, pressures and interfacial friction, and some bounded numerical oscillations. Following our numerical experiment, we developed a systematic approach to improve the two-phase level tracking method. We present this approach and the results of implementation in the TRAC-BWR code.     

Acquisition of categorical color perception: A perceptual learning approach to the linguistic relativity hypothesis.

Color perception can be categorical: Between-category discriminations are more accurate than equivalent within-category discrimination. The effects could be inherited, learned, or both. The authors provide evidence that supports the possibility of learned categorical perception (CP). Experiment 1 demonstrated that observers' color discrimination is flexible and improves through repeated practice. Experiment 2 demonstrated that category learning simulates effects of "natural" color categories on color discrimination. Experiment 3 investigated the time course of acquired CP. Experiment 4 found that CP effects are acquired through hue- and lightness-based category learning and obtained interesting data on the dimensional perception of color. The data are consistent with the possibility that language may shape color perception and suggest a plausible mechanism for the linguistic relativity hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)