Phase behavior of hard spheres confined between parallel hard plates: Manipulation of colloidal crystal structures by confinement

We study the phase behavior of hard spheres confined between two parallel hard plates using extensive computer simulations. We determine the full equilibrium phase diagram for arbitrary densities and plate separations from one to five hard-sphere diameters using free energy calculations. We find a first-order fluid-solid transition, which corresponds to either capillary freezing or melting depending on the plate separation. The coexisting solid phase consists of crystalline layers with either triangular or square symmetry. Increasing the plate separation, we find a sequence of crystal structures from n triangular to (n+1) square to (n+1) triangular, where n is the number of crystal layers, in agreement with experiments on colloids. At high densities, the transition between square to triangular phases are intervened by intermediate structures, e.g., prism, buckled, and rhombic phases.Comment: 9 pages, 4 figures. Accepted for publication in J. Phys.: Condens. Matte

Stable crystalline lattices in two-dimensional binary mixtures of dipolar particles

The phase diagram of binary mixtures of particles interacting via a pair potential of parallel dipoles is computed at zero temperature as a function of composition and the ratio of their magnetic susceptibilities. Using lattice sums, a rich variety of different stable crystalline structures is identified including $A_mB_n$ structures. [$A$ $(B)$ particles correspond to large (small) dipolar moments.] Their elementary cells consist of triangular, square, rectangular or rhombic lattices of the $A$ particles with a basis comprising various structures of $A$ and $B$ particles. For small (dipolar) asymmetry there are intermediate $AB_2$ and $A_2B$ crystals besides the pure $A$ and $B$ triangular crystals. These structures are detectable in experiments on granular and colloidal matter.Comment: 6 pages - 2 figs - phase diagram update

First report on the lipid composition of milk from livestock in Cuba Primer informe de la composición lipídica de la leche en ganado de interés económico en Cuba

In the framework of the project IBEROFUN «Incorporation of new functional ingredients to food as a contribution to health promotion and/or prevention of diseases of the Latin American population», Ref: 110AC0386, a collaborative work on the lipid composition of milk from cows, buffaloes and goats was carried out by the National Center for Animal and Plant Health (CENSA) and the Research Institute of Food Science (CIAL) in Spain

Impacto de la deficiencia de glucosa-6-fosfato deshidrogenasa en individuos de zonas endémicas de malaria

Glucose-6-phosphate dehydrogenase (G6PD) is a cytoplasmic enzyme that is essential for a cell’s capacity to withstand oxidant stress generated by molecules or reactive oxygen species (ROS) in human cells that could damage the integrity of cellular structures. G6PD deficiency (G6PDd) is one of the most common hereditary hemolytic disorders affecting about 400 million people worldwide. Its distribution and major frequency occurs mainly in tropical and subtropical regions of the world where malaria is or has been endemic. Several studies have demonstrated a potential protective effect against severe forms of malaria; conversely, individuals with G6PDd show complications and adverse clinical manifestations such as hemolytic anemia after treatment with antimalarial drugs such as primaquine and other 8-aminoquinolines (8AQ) drugs. Despite the evidence of the potential negative effects in developing countries endemic for malaria there is no information or a limited number of studies aimed to investigate the prevalence and frequency of G6PD deficient variants that supports treating policies in these vulnerable populations suffering of malaria.Revista Portal de Ciencias, No. 8, June 2015: 45-58La glucosa-6-fosfato deshidrogenasa (G6PD) es una enzima citoplasmática esencial para contrarrestar el estrés oxidativo generado por moléculas o especies reactivas de oxígeno (ROS) en las células humanas, las que podrían dañar su integridad. La deficiencia de glucosa-6-fosfato deshidrogenasa (G6PDd) constituye uno de los desórdenes hemolíticos hereditarios más comunes, afectando a cerca de 400 millones de personas a nivel mundial.Su distribución y mayor frecuencia ocurre principalmente en regiones tropicales y subtropicales del mundo en donde la malaria es o ha sido endémica. Diversos estudios han demostrado un potencial efecto protector de la G6PDd contra formas graves de malaria; asimismo, en estos individuos se han observado complicaciones y manifestaciones clínicas adversas como la anemia hemolítica, después de recibir tratamiento con drogas antimaláricas como la primaquina y otras drogas de la familia de las 8-aminoquinolinas (8AQ). A pesar de la evidencia de sus efectos negativos potenciales, en muchos países en vías de desarrollo endémicos de malaria existen pocos estudios o un vacío absoluto de información sobre la prevalencia y frecuencia de alelos deficientes del gen de la G6PD que apoyen los esquemas de tratamiento dirigidos a estas poblaciones vulnerables que padecen de malaria.Revista Portal de Ciencias, No. 8, junio 2015: 45-5

Removal of Phenolic Compounds from Water Using Copper Ferrite Nanosphere Composites as Fenton Catalysts

The authors affiliated to the University of Jaén (Department of Inorganic and Organic Chemistry) acknowledge financial support from the Spanish Ministry of Economy, Industry and Competitiveness and from FEDER (Project CTQ2016-80978-C2-1-R). L. Mateus thanks the Asociación Universitaria Iberoamericana de Postgrado (AUIP) and University of Jaén for their grant and financial support.Copper ferrites containing Cu+ ions can be highly active heterogeneous Fenton catalysts due to synergic effects between Fe and Cu ions. Therefore, a method of copper ferrite nanosphere (CFNS) synthesis was selected that also permits the formation of cuprite, obtaining a CFNS composite that was subsequently calcined up to 400 °C. Composites were tested as Fenton catalysts in the mineralization of phenol (PHE), p-nitrophenol (PNP) and p-aminophenol (PAP). Catalysts were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and magnetic measurements. Degradation of all phenols was practically complete at 95% total organic carbon (TOC) removal. Catalytic activity increased in the order PHE < PNP < PAP and decreased when the calcination temperature was raised; this order depended on the electronic effects of the substituents of phenols. The as-prepared CFNS showed the highest catalytic activity due to the presence of cubic copper ferrite and cuprite. The Cu+ surface concentration decreased after calcination at 200 °C, diminishing the catalytic activity. Cuprite alone showed a lower activity than the CFNS composite and the homogeneous Fenton reaction had almost no influence on its overall activity. CFNS activity decreased with its reutilization due to the disappearance of the cuprite phase. Degradation pathways are proposed for the phenols.This research was funded by Spanish Ministry of Economy, Industry and Competitiveness and FEDER (grant number CTQ2016-80978-C2-1-R), Asociación Universitaria Iberoamericana de Postgrado (AUIP) and University of Jaén

Enteritis necrotizante endotoxémica por Clostridium perfringes en un perro

Se describe un caso clínico de enteritis necrotizante, debida a liberación de enterotoxinas por sobrecrecimiento de Clostridium perfringes, en un perro. Tras diversos tratamientos médicos y quirúrgicos, las lesiones intestinales involucionaron y el paciente se recuperó completamente.

Surface-charge-induced freezing of colloidal suspensions

Using grand-canonical Monte Carlo simulations we investigate the impact of charged walls on the crystallization properties of charged colloidal suspensions confined between these walls. The investigations are based on an effective model focussing on the colloids alone. Our results demonstrate that the fluid-wall interaction stemming from charged walls has a crucial impact on the fluid's high-density behavior as compared to the case of uncharged walls. In particular, based on an analysis of in-plane bond order parameters we find surface-charge-induced freezing and melting transitions

Downstream processing of Isochrysis galbana: a step towards microalgal biorefinery

An algae-based biorefinery relies on the efficient use of algae biomass through its fractionation of several valuable/bioactive compounds that can be used in industry. If this biorefinery includes green platforms as downstream processing technologies able to fulfill the requirements of green chemistry, it will end-up with sustainable processes. In the present study, a downstream processing platform has been developed to extract bioactive compounds from the microalga Isochrysis galbana using various pressurized green solvents. Extractions were performed in four sequential steps using (1) supercritical CO2 (ScCO2), (2) ScCO2/ethanol (Gas Expanded Liquid, GXL), (3) pure ethanol, and (4) pure water as solvents, respectively. The residue of the extraction step was used as the raw material for the next extraction. Optimization of the ScCO2 extraction was performed by factorial design in order to maximize carotenoid extraction. During the second step, different percentages of ethanol were evaluated (15%, 45% and 75%) in order to maximize the extraction yield of fucoxanthin, the main carotenoid present in this alga; the extraction of polar lipids was also an aim. The third and fourth steps were performed with the objective of recovering fractions with high antioxidant activity, eventually rich in carbohydrates and proteins. The green downstream platform developed in this study produced different extracts with potential for application in the food, pharmaceutical and cosmetic industries. Therefore, a good approach for complete revalorization of the microalgae biomass is proposed, by using processes complying with the green chemistry principlesThe authors acknowledge funding from the EU MIRACLES project (7th Framework Program - Grant Agreement No. 613588). B.G.L. thanks MINECO (Ministerio de Economía y Competitividad) for her Juan de la Cierva postdoctoral research contract. M.H. thanks MINECO for his Ramón y Cajal postdoctoral research contract

Relationships between CYP2D6 phenotype, breast cancer and hot flushes in women at high risk of breast cancer receiving prophylactic tamoxifen: results from the IBIS-I trial

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