Water-Based Graphene Oxide–Silicon Hybrid Nanofluids—Experimental and Theoretical Approach

In the current paper, a new hybrid nanofluid based on graphene oxide sheets and silicon nanoparticles is proposed for thermal applications. GO sheets and Si nanoparticles with different mixture ratios are dispersed in distilled water. Dynamic viscosity is measured at temperatures within the range 20–50 °C and the values are compared to the results available in the literature. The results indicated that the viscosity increases with increasing the mixture ratio of graphene oxide. A new correlation for the dynamic viscosity based on the experimental findings is proposed. Finally, the criteria for the performance of new hybrid nanofluid for thermal applications are analyzed.     

Annual anomalies and trends for TOMS reflectivities (1978–2005) in the Southern Hemisphere

Annual anomalies of Lambertian equivalent reflectivity (LER) retrieved from the total ozone mapping spectrometer spanning the period November 1978–November 2005 were studied in the Southern Hemisphere, in a region bounded by 0° S and 60° S, and their trends were estimated. With the exception of few regions where the variable may represent the contribution of both cloudiness and snow, trends in LER anomalies provided an evolution of total cloudiness. On average, the study region experienced a net increase in LER values of 0.78 reflectivity units (RU) decade^?1; if only significant trend values are considered this figure increased to 1.18 RU decade^?1. The region that showed the largest upward trend, up to 4 RU decade^?1, was located over the eastern Pacific, off the coasts of Chile and Peru, where the presence of marine stratocumulus is frequent. Despite the overall positive trend there were regions that yielded a negative one, most notably the tropical latitudes of South America and Africa. The yearly zonal means also showed a positive trend at all latitudes, but significance occurred beyond 20° S only. Correlation maps between LER anomalies and five different circulation indices were also introduced. The indices with the highest and lowest number of significant correlation values were the Madden–Julian oscillation at 70° E and the quasi-biennial Oscillation, respectively.     

Investigations on Sweet Cherry Phenolic Degradation During Thermal Treatment Based on Fluorescence Spectroscopy and Inactivation Kinetics

Five anthocyanins were detected in the sweet cherry extract as follows: cyanidin 3-rutinoside, cyanidin 3-glucoside, peonidin 3-rutinoside, peonidin 3-glucoside, and pelargonidin 3-rutinoside, whereas the cyanidin 3-rutinoside was found to be in the highest amount. The effect of thermal treatment on the degradation of the polyphenolic compounds in sweet cherry extract was investigated in the range of 70–120 °C by means of fluorescence spectroscopy and spectrophotometric techniques. The fluorescence spectra were dominated by emission bands with maximum ranging from 356 nm at 25 °C to 350 nm at 110 °C. The heating of sweet cherry extract resulted in structural changes that led to a significant decrease in fluorescence intensity when increasing temperature. Degradation rate constants were estimated using a fractional conversion kinetic model. The activation energy values revealed a higher-temperature dependence of antioxidant activity, followed by anthocyanins, total polyphenols, and total flavonoids.     

Effects of social exclusion in trauma survivors with posttraumatic stress disorder.

Trauma survivors with posttraumatic stress disorder (PTSD) often experience or report social stigmatization and isolation. Williams (2001) provided an experimental paradigm to assess behavioral effects of social exclusion. This paradigm (face-to-face version) has been applied in a 2 × 2 group × experimental condition design. Participants in the PTSD group (N = 16) and the nontraumatized control group (N = 25) were randomly assigned to an exclusion or inclusion condition. The results showed interaction effects for main psychopathological assessments (depression, anxiety, psychoticism) and expected main effects for the majority of outcome measures (psychopathology, well-being, belonging, and meaningful existence). The research concludes that a general assumption of elevated levels of self-perceived social exclusion in PTSD patients has to be considered in terms of differentiated psychopathological effects of exclusion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dietary intakes and food sources of fat and fatty acids in Guatemalan schoolchildren: A cross-sectional study

Background  

Consumption of healthy diets that contribute with adequate amounts of fat and fatty acids is needed for children. Among Guatemalan children, there is little information about fat intakes. Therefore, the present study sought to assess intakes of dietary fats and examine food sources of those fats in Guatemalan children.     

Some metal compounds in the phase of crosslinked ionic polymer—precursors for new sorbents and catalysts

A commercial crosslinked ionic polymer AV‐17 containing ? N(CH₃)₃Cl groups was used. The common compounds of Bi(III) and Al(III); Bi(III) and Cr(III); Bi(III) and Fe(III); Bi(III) and FeOOH and of three components—Bi(III), Fe(III), and Cr(III); Bi(III), FeOOH, and Cr(III) were obtained in the AV‐17 polymer phase and investigated using scanning electron microscopy, powder X‐ray diffraction, thermogravimetric analysis, and Fourier‐transform infrared spectroscopy. It was shown that metal‐containing compounds were concentrated on the surface of the polymer granules. The compounds were in the crystalline (BiOCl) or amorphous (jarosites and oxihydroxides) state. The morphology and composition of the metal‐containing ultra dispersed particles were different on the surface and in the volume of the polymer granule. Most of the metal‐containing compounds were in the form of pseudo spherical particles, but compounds containing Bi(III) and FeOOH in the volume of AV‐17 granule, were in the form of clew of nanometer fibers. Thermogravimetric analysis (in an N₂ atmosphere) in the range 24–1000°C of the metallic compounds containing polymer was also carried out. The metal‐containing polymer samples were stable up to 120°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Probiotics: An alternative strategy for combating salmonellosis: Immune mechanisms involved

Salmonella produces infections of different nature and severity depending of many factors including the Salmonella serovar involved, strain virulence, infective dose, host animal species, age and immune status of the host. The treatments against Salmonella infections rely on supportive and antibiotic therapy to eliminate the pathogen, but the development of resistance by Salmonella to the antimicrobials most commonly used limits its efficacy. Other disadvantages of antibiotic treatments are that they can lead to acute diarrhea (antimicrobials normally induce an imbalance of intestinal bacterial flora) and may produce chronic toxicity. Considering this undesired consequences of antibiotics and because at the present there are no effective oral vaccines which protect against salmonellosis, scientists have been searching for alternative methods to control enteric infections. In the present review, probiotics are proposed as an attractive possibility to attend this concern. Probiotic are live microorganisms, which when administered in adequate amounts confer a health benefit on the host. In vitro and in vivo studies showed the effectiveness of probiotic administration in the prevention or in the treatment against Salmonella infection. There are several mechanisms by which probiotic strains might exert their effects. They include non immune mechanisms (stabilization of the gut mucosal barrier, competition for adhesion, secretion of antimicrobial substances, etc.) and the modulation of the mucosal and systemic immune responses. These mechanisms are species and/or strain specific. There are also evidences that in some cases, a mix of probiotic strains can be more useful than each strain alone against this infection. In addition, the presence of one or more probiotic strains in a fermented product can improve the beneficial properties of the probiotic strains involved. It was also reviewed the security of probiotics administration after Salmonella infection in healthy host and in immunosuppressed or babies hosts. Although, the major part of the researches were performed in animal models through in vivo assays or by in vitro studies using human cell lines, some studies carried out in humans to verify the probiotic effects were also addressed in the present review. Nevertheless, is of critical importance to perform more clinical trials in humans to validate the results obtained with each specific probiotic strain or probiotic product.