Metastability and front propagation in the first-order optical Fréedericksz transition

A general dynamical model for the first-order optical Fréedericksz transition incorporating spatial transverse inhomogeneities and hydrodynamic effects is discussed in the framework of a time-dependent Ginzburg-Landau model. The motion of an interface between two coexisting states with different director orientations is considered. A uniformly translating front solution of the dynamical equations for the motion of that interface is described.

State-to-state reaction probabilities within the quantum transition state framework

Rigorous quantum dynamics calculations of reaction rates and initial state-selected reaction probabilities of polyatomic reactions can be efficiently performed within the quantum transition state concept employing flux correlation functions and wave packet propagation utilizing the multi-configurational time-dependent Hartree approach. Here, analytical formulas and a numerical scheme extending this approach to the calculation of state-to-state reaction probabilities are presented. The formulas derived facilitate the use of three different dividing surfaces: two dividing surfaces located in the product and reactant asymptotic region facilitate full state resolution while a third dividing surface placed in the transition state region can be used to define an additional flux operator. The eigenstates of the corresponding thermal flux operator then correspond to vibrational states of the activated complex. Transforming these states to reactant and product coordinates and propagating them into the respective asymptotic region, the full scattering matrix can be obtained. To illustrate the new approach, test calculations study the D + H2(ν, j) → HD(ν′, j′) + H reaction for J = 0.

Dynamics of transient pattern formation in nematic liquid crystals

We analyze the dynamics of a transient pattern formation in the Fréedericksz transition corresponding to a twist geometry. We present a calculation of the time-dependent structure factor based on a dynamical model which incorporates consistently the coupling of the director field with the velocity flow and also the effect of fluctuations. The appearance and development of a characteristic periodicity is described in terms of the time dependence of the maximum of the structure factor. We find a well-defined time for the appearance of the pattern and a subsequent stage of pattern development in which the characteristic periodicity tends to an asymptotic value.

Ground- and excited-state properties of M-center oxygen vacancy aggregates in the bulk and the surface of MgO

Aggregates of oxygen vacancies (F centers) represent a particular form of point defects in ionic crystals. In this study we have considered the combination of two oxygen vacancies, the M center, in the bulk and on the surface of MgO by means of cluster model calculations. Both neutral and charged forms of the defect M and M+ have been taken into account. The ground state of the M center is characterized by the presence of two doubly occupied impurity levels in the gap of the material; in M+ centers the highest level is singly occupied. For the ground-state properties we used a gradient corrected density functional theory approach. The dipole-allowed singlet-to-singlet and doublet-to-doublet electronic transitions have been determined by means of explicitly correlated multireference second-order perturbation theory calculations. These have been compared with optical transitions determined with the time-dependent density functional theory formalism. The results show that bulk M and M+ centers give rise to intense absorptions at about 4.4 and 4.0 eV, respectively. Another less intense transition at 1.3 eV has also been found for the M+ center. On the surface the transitions occur at 1.6 eV (M+) and 2 eV (M). The results are compared with recently reported electron energy loss spectroscopy spectra on MgO thin films.

Dissociation from BiP and Retrotranslocation of Unassembled Immunoglobulin Light Chains Are Tightly Coupled to Proteasome Activity

Unassembled immunoglobulin light chains expressed by the mouse plasmacytoma cell line NS1 (KNS1) are degraded in vivo with a half-life of 50-60 min in a way that closely resembles endoplasmic reticulum (ER)-associated degradation (Knittler et al., 1995). Here we show that the peptide aldehydes MG132 and PS1 and the specific proteasome inhibitor lactacystin effectively increased the half-life of KNS1, arguing for a proteasome-mediated degradation pathway. Subcellular fractionation and protease protection assays have indicated an ER localization of KNS1 upon proteasome inhibition. This was independently confirmed by the analysis of the folding state of KNS1and size fractionation experiments showing that the immunoglobulin light chain remained bound to the ER chaperone BiP when the activity of the proteasome was blocked. Moreover, kinetic studies performed in lactacystin-treated cells revealed a time-dependent increase in the physical stability of the BiP-KNS1complex, suggesting that additional proteins are present in the older complex. Together, our data support a model for ER-associated degradation in which both the release of a soluble nonglycosylated protein from BiP and its retrotranslocation out of the ER are tightly coupled with proteasome activity.

Desigualdades de género en la salud relacionadas con lacombinación de la vida laboral y familiar en Cataluña

Objetivos: Los objetivos de este estudio fueron: 1) analizar las desigualdades de género en la salud en la población asalariada, de 25 a 64 años, casada o que vive en pareja en Cataluña y 2) examinar las desigualdades de género en la relación entre las exigencias de la esfera doméstica y familiar, las horas de trabajo remunerado y la salud.Métodos: Los datos proceden de la Encuesta de Salud de Cataluña de 2006 (ESCA 2006). La población analizada fueron hombres y mujeres entre 25 y 64 años, asalariados y que convivían en pareja (N =4.537). Las variables dependientes fueron el estado de salud percibido, la salud mental, el consumo de psicofármacos y las horas de sueño. Las variables explicativas fueron el número de horas de trabajo remunerado, número de personas en el hogar, la convivencia con menores de 12 años, la convivencia con personas entre 65 y 74 años, la convivencia con personas mayores de 74 años y, tener una persona contratada para realizar trabajo doméstico.Resultados: Convivir con menores de 12 años se asoció negativamente con mala salud y con consumo de psicofármacos en las mujeres; que el consumo de psicofármacos en mujeres estaba relacionado positivamente con la convivencia con personas entre 65 y 74 años y con la convivencia con mayores de 74 años (aOR: 2,60; 95% IC: 1,41-4,80 y aOR: 2,93; 95% IC: 1,58-5,44 respectivamente) y en los dos sexos los largos horarios de trabajo se asociaron con problemas de salud mental aunque en mayor proporción en hombres.Conclusión: La combinación de las exigencias familiares y las horas de trabajo remunerado se asocia con diversos indicadores de salud con diferentes patrones en hombres y en mujeres.

Self-Construction, Cognitive Conflicts, and Disordered Eating Attitudes in Young Women

The aim of this study is to identify cognitive variables that predict disordered eating attitudes in a nonclinical sample composed of 50 female university students. Repertory grid technique was used to assess cognitive features of self-construing and cognitive conflicts. Drive for Thinness and Body Dissatisfaction scales from the Eating Disorder Inventory 2 were used as dependent variables, as previous studies suggested that high scores on these scales are associated with the risk of developing or aggravating eating syndromes. Results suggest that drive for thinness can be associated with cognitive conflicts, whereas body dissatisfaction may be higher for those who construct themselves as inadequate and similar to others. In addition, both dependent variables were predicted by being younger and having a higher body mass index.

Impacte d'un programa d'activitat física basat en el mètode Klapp i Stretching Global Actiu sobre la postura de persones adultes amb escoliosi idiopàtica

La simetria entre espatlles i l’alçada de les dues crestes ilíaques es perd quan es pateix escoliosi. Aquest empitjorament de la bona postura té conseqüències negatives per a la salut, especialment en el sistema musculoesquelètic. L’objecte principal d’aquest treball és avaluar l’impacte d’un programa d’activitat física basat en la combinació dels mètodes “Klapp” i l’“Stretching Global Actiu” sobre la postura en bipedestació de persones adultes que pateixen escoliosi idiopàtica. L’aplicació d’ambdós mètodes de forma individual no obtenen millores en aquests paràmetres en persones adultes, però en canvi en nens i nenes sí. El treball és un estudi experimental en el qual es va assignar un subjecte al grup intervenció i un subjecte al grup control. El subjecte del grup intervenció va realitzar un programa de 20 sessions de 45 – 60 minuts de treball amb aquests dos mètodes de treball físic. El subjecte del grup control va seguir la seva activitat habitual. Abans i després de la intervenció, es varen mesurar les variables dependents principals i secundaries respectivament. Els resultats obtinguts han revelat una petita millora en la simetria de les espatlles (+0,2 cms.) en el grup intervenció però no en la simetria de l’altura de les crestes ilíaques. El grup control no ha presentat canvis. Per tant, podem dir que és útil utilitzar la combinació dels dos mètodes físics per a millorar la postura en persones adultes que pateixen escoliosi idiopàtica.

Assessing changes in Cd phytoavailability to tomato in amended calcareous soils.

A plot study was conducted to assess changes in Cd phytoavailability to a tomato cultivar in an agricultural soil in Southeastern Spain amended in two different ways (A and B), under controlled conditions. The experimental soil corresponded to a fine-loamy carbonatic thermic Calcidic Haploxeroll (Soil Survey Staff, 1998). A) Soil was amended with a single application of sewage sludge from a municipal source that had a total Cd concentration of 0.5 mg kg-1 at a rate that represented a final average concentration in the mixture of soil and sludge of less than 50 µg Cd kg-1. B) The amendment consisted of the addition of a mineral fertiliser with the same amount of NPK as in the sewage sludge application. The final levels of Cd were supposed to be negligible. A plot series without amendments was also performed (C). DTPA plus triethanolamine, and ammonium acetate extractable fractions in soils were analysed for all the plots. The time-dependent Cd accumulation in different parts of the tomato plants was studied by means of a Cd salt treatment. For each block (A, B, and C) four levels of Cd (0, 3, 30, 100 mg kg-1) were added as CdCl2. There was a significant increase in plant Cd after the initial cropping. Tomato stems, leaves and fruits were analysed separately for Cd determination. Differential Cd distribution and accumulation in tomato parts was detected.

Metabolic effects of insulin and IGFs on gilthead sea bream (Sparus aurata) muscle cells.

Primary cultures of gilthead sea bream myocytes were performed in order to examine the relative metabolic function of insulin compared with IGF-I and IGF-II (insulin-like growth factors, IGFs) at different stages in the cell culture. In these cells, the in vitro effects of insulin and IGFs on 2-deoxyglucose (2-DG) and L-alanine uptake were studied in both myocytes (day 4) and small myotubes (day 9). 2-DG uptake in gilthead sea bream muscle cells was increased in the presence of insulin and IGFs in a time dependent manner and along with muscle cell differentiation. On the contrary, L-alanine uptake was also stimulated by insulin and IGFs but showed an inverse pattern, being the uptake higher in small myocytes than in large myotubes. The results of preincubation with inhibitors (PD-98059, wortmannin, and cytochalasin B) on 2-DG uptake indicated that insulin and IGFs stimulate glucose uptake through the same mechanisms, and evidenced that mitogenesis activator protein kinase (MAPK) and PI3K-Akt transduction pathways mediate the metabolic function of these peptides. In the same way, we observed that GLUT4 protein synthesis was stimulated in the presence of insulin and IGFs in gilthead sea bream muscle cells in a different manner at days 4 or 9 of the culture. In summary we describe here, for the first time, the effects of insulin and IGFs on 2-DG and L-alanine uptake in primary culture of gilthead sea bream muscle cells. We show that both MAPK and PI3K-Akt transduction pathways are needed in order to control insulin and IGFs actions in these cells. Moreover, changes in glucose uptake can be explained by the action of the GLUT4 transporter, which is stimulated in the presence of insulin and IGFs throughout the cell culture.

Mueller matrix microscope with a dual continuous rotating compensator setup and digital demodulation

In this paper we describe a new Mueller matrix (MM) microscope that generalizes and makes quantitative the polarized light microscopy technique. In this instrument all the elements of the MU are simultaneously determined from the analysis in the frequency domain of the time-dependent intensity of the light beam at every pixel of the camera. The variations in intensity are created by the two compensators continuously rotating at different angular frequencies. A typical measurement is completed in a little over one minute and it can be applied to any visible wavelength. Some examples are presented to demonstrate the capabilities of the instrument.

Probiotic Sonicates Selectively Induce Mucosal Immune Cells Apoptosis Through Ceramide Generation Via Neutral Sphingolyelinase.

Background: Probiotics appear to be beneficial in inflammatory bowel disease, but their mechanism of action is incompletely understood. We investigated whether probiotic-derived sphingomyelinase mediates this beneficial effect. Methodology/Principal Findings: Neutral sphingomyelinase (NSMase) activity was measured in sonicates of the probiotic L.brevis (LB)and S. thermophilus (ST) and the non-probiotic E. coli EC) and E. faecalis (EF). Lamina propria mononuclear cells (LPMC) were obtained from patients with Crohn"s disease (CD) and Ulcerative Colitis (UC), and peripheral blood mononuclear cells (PBMC) from healthy volunteers, analysing LPMC and PBMC apoptosis susceptibility, reactive oxygen species (ROS) generation and JNK activation. In some experiments, sonicates were preincubated with GSH or GW4869, a specific NSMase inhibitor. NSMase activity of LB and ST was 10-fold that of EC and EF sonicates. LB and ST sonicates induced significantly more apoptosis of CD and UC than control LPMC, whereas EC and EF sonicates failed to induce apoptosis. Pre-stimulation with anti-CD3/CD28 induced a significant and time-dependent increase in LB-induced apoptosis of LPMC and PBMC. Exposure to LB sonicates resulted in JNK activation and ROS production by LPMC. NSMase activity of LB sonicates was completely abrogated by GW4869, causing a dose-dependent reduction of LB -induced poptosis. LB and ST selectively induced immune cell apoptosis, an effect dependent on the degree of cell activation and mediated by bacterial NSMase. Conclusions: These results suggest that induction of immune cell apoptosis is a mechanism of action of some probiotics and that NSMase-mediated ceramide generation contributes to the therapeutic effects of probiotics.

L'impacte d'un programa de tennis com a eina de millora de la qualitat de vida i l'estrès percebut en dones físicament inactives d'entre 43 i 50 anys

Introducció: L’activitat física és una necessitat imprescindible per a la salut de les persones, i tot i ser conscients dels seus beneficis encara es troben alts percentatges d’inactivitat física i sedentarisme. Per aquest motiu, els objectius principals d’aquest estudi són esbrinar si les dones adultes d’entre 43 i 50 anys que realitzen activitat física regularment, més concretament que practiquen l’esport del tennis, tenen una qualitat de vida i un estrès percebut millor que les que no realitzen activitat física, i per tant, valorar l’impacte d’un programa de tennis adequat i específic, és a dir, adaptat a les característiques i les necessitats dels alumnes, com a eina per millorar aquestes dues variables: l’estrès percebut i la qualitat de vida. Metodologia: El treball és un estudi experimental el qual consta d’una mostra total de 12 dones, 6 es varen assignar al grup control (practiquen el tennis) i 6 al grup intervenció (no realitzen AF), i totes elles de manera aleatòria. Les participants del grup intervenció varen realitzar un programa de 8 sessions de 60 minuts de treball durant 4 setmanes, mentre que les participants del grup control van seguir la seva rutina habitual. Les variables dependents (qualitat de vida i estrès percebut) es varen mesurar abans i després de la intervenció. Resultats: Els resultats obtinguts mostren, pel que fa al grup intervenció, millores significatives respecte a les dues variables mentre que el grup control presenta alguna mínima millora puntual però, en general no es produeixen canvis. Quan a la variable de qualitat de vida, les participants del grup intervenció han obtingut millores en les 8 dimensions del qüestionari un cop finalitzat el programa, les quals han estat més significatives pel que fa al rol emocional i la funció física. I respecte a l’estrès percebut, el grup intervenció ha aconsegui reduir el seu nivell d’estrès 3’17 punts. Discussió: Per tant, podem dir que el tennis, amb el disseny adequat d’un programa, millora l’estat de salut de les persones, en aquest cas redueix l’estrès percebut i millora la qualitat de vida. Extretes les conclusions i coneixent l’elevat nombre de dones que practiquen el tennis és de gran interès i molt factible oferir aquest programa a clubs de tennis amb l’objectiu de millorar la salut de les persones.

Accounting for adsorption and desorption in Lattice Boltzmann simulations

We report a Lattice-Boltzmann scheme that accounts for adsorption and desorption in the calculation of mesoscale dynamical properties of tracers in media of arbitrary complexity. Lattice Boltzmann simulations made it possible to solve numerically the coupled Navier-Stokes equations of fluid dynamics and Nernst-Planck equations of electrokinetics in complex, heterogeneous media. With the moment propagation scheme, it became possible to extract the effective diffusion and dispersion coefficients of tracers, or solutes, of any charge, e.g., in porous media. Nevertheless, the dynamical properties of tracers depend on the tracer-surface affinity, which is not purely electrostatic and also includes a species-specific contribution. In order to capture this important feature, we introduce specific adsorption and desorption processes in a lattice Boltzmann scheme through a modified moment propagation algorithm, in which tracers may adsorb and desorb from surfaces through kinetic reaction rates. The method is validated on exact results for pure diffusion and diffusion-advection in Poiseuille flows in a simple geometry. We finally illustrate the importance of taking such processes into account in the time-dependent diffusion coefficient in a more complex porous medium.

Polyphenol intake and mortality risk: a re-analysis of the PREDIMED trial

Background: Polyphenols may lower the risk of cardiovascular disease (CVD) and other chronic diseases due to their antioxidant and anti-inflammatory properties, as well as their beneficial effects on blood pressure, lipids and insulin resistance. However, no previous epidemiological studies have evaluated the relationship between the intake of total polyphenols intake and polyphenol subclasses with overall mortality. Our aim was to evaluate whether polyphenol intake is associated with all-cause mortality in subjects at high cardiovascular risk. Methods: We used data from the PREDIMED study, a 7,447-participant, parallel-group, randomized, multicenter, controlled five-year feeding trial aimed at assessing the effects of the Mediterranean Diet in primary prevention of cardiovascular disease. Polyphenol intake was calculated by matching food consumption data from repeated food frequency questionnaires (FFQ) with the Phenol-Explorer database on the polyphenol content of each reported food. Hazard ratios (HR) and 95% confidence intervals (CI) between polyphenol intake and mortality were estimated using time-dependent Cox proportional hazard models. Results: Over an average of 4.8 years of follow-up, we observed 327 deaths. After multivariate adjustment, we found a 37% relative reduction in all-cause mortality comparing the highest versus the lowest quintiles of total polyphenol intake (hazard ratio (HR) = 0.63; 95% CI 0.41 to 0.97; P for trend = 0.12). Among the polyphenol subclasses, stilbenes and lignans were significantly associated with reduced all-cause mortality (HR =0.48; 95% CI 0.25 to 0.91; P for trend = 0.04 and HR = 0.60; 95% CI 0.37 to 0.97; P for trend = 0.03, respectively), with no significant associations apparent in the rest (flavonoids or phenolic acids). Conclusions: Among high-risk subjects, those who reported a high polyphenol intake, especially of stilbenes and lignans, showed a reduced risk of overall mortality compared to those with lower intakes. These results may be useful to determine optimal polyphenol intake or specific food sources of polyphenols that may reduce the risk of all-cause mortality.