Flow effects on the dendritic microstructure of AlSi-base alloys

Fluid flow changes heat and mass transport during solidification, thereby affecting the evolution of the microstructure. In order to quantify effects of convection, it is important that fluid flow can be modified experimentally. We performed directional solidification experiments with binary AlSi alloys of different compositions, using a microgravity environment for diffusive solidification and adding rotating magnetic fields to generate flow. Flow velocities up to 10 mm/s and various solidification velocities were realized while maintaining a constant temperature gradient at the solid-liquid interface. The microstructure observed in samples processed on earth and in space is characterized by primary and secondary dendrite arm spacing and the fractal dimension of the dendrites. It is found that fluid flow usually accelerates growth and coarsening of the dendritic structures and leads to new kinetic laws. The branching of dendritic networks, however, is hardly affected by flow.     

Cocaine treatment and prenatal environment interact to disrupt intergenerational maternal behavior in rats.

The link between impaired maternal behavior (MB) and cocaine treatment could result from drug-induced decreases in maternal reactivity to offspring, prenatal drug exposure (PDE) in offspring that could alter their ability to elicit MB, or the interaction of both, which could subsequently impair MB of the 1st-generation dams. Following chronic or intermittent cocaine or saline treatment during gestation, rat dams rearing natural or cross-fostered litters were compared along with untreated dams for MB. Untreated 1st-generation females with differentially treated rearing dams and PDE were tested for MB with their natural litters. The authors report disruptions in MB in dams and their 1st-generation offspring, attributable to main and interaction effects of maternal treatment, litter PDE, and rearing experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exposure therapy for posttraumatic stress disorder in a residential substance use treatment facility.

Clinical lore abounds when discussing the issue of treating trauma-related symptoms in substance-dependent clients. Historically, clinicians have wondered whether they should wait until the client has gained substantial abstinence from abused substances before initiating trauma treatment or if trauma treatment should be conducted during substance use treatment. Furthermore, questions arise with regard to exactly how trauma-related symptoms should be addressed and how trauma treatment should be incorporated into the recovery process. In this article, the growing literature suggesting that posttraumatic stress disorder (PTSD) can be treated concurrently with substance use disorders is reviewed. In addition, the unique challenges of implementing treatment for PTSD with substance-dependent clients seeking treatment in a residential treatment facility are discussed. Specifically, we provide concrete suggestions about how to utilize prolonged exposure, a very effective treatment for PTSD, with clients in a residential substance use treatment facility, including use of the internet to facilitate exposure therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitation of Human Whole‐Body Synthesis‐Secretion Rates of Docosahexaenoic Acid and Eicosapentaenoate Acid from Circulating Unesterified α‐Linolenic Acid at Steady State

The rate at which dietary α‐linolenic acid (ALA) is desaturated and elongated to its longer‐chain n‐3 polyunsaturated fatty acid (PUFA) in humans is not agreed upon. In this study, we applied a methodology developed using rodents to investigate the whole‐body, presumably hepatic, synthesis‐secretion rates of esterified n‐3 PUFA from circulating unesterified ALA in 2 healthy overweight women after 10 weeks of low‐linoleate diet exposure. During continuous iv infusion of d5‐ALA, 17 arterial blood samples were collected from each subject at ?10, 0, 10, 20, 40, 60, 80, 100, 120, 150, 180, and 210 min, and at 4, 5, 6, 7, and 8 h after beginning infusion. Plasma esterified d5‐n‐3 PUFA concentrations were plotted against the infusion time and fit to a sigmoidal curve using nonlinear regression. These curves were used to estimate kinetic parameters using a kinetic analysis developed using rodents. Calculated synthesis‐secretion rates of esterified eicosapentaenoate, n‐3 docosapentaenoate, docosahexaenoic acid, tetracosapentaenate, and tetracosahexaenoate from circulating unesterified ALA were 2.1 and 2.7; 1.7 and 5.3; 0.47 and 0.27; 0.30 and 0.30; and 0.32 and 0.27 mg/day for subjects S01 and S02, respectively. This study provides new estimates of whole‐body synthesis‐secretion rates of esterified longer‐chain n‐3 PUFA from circulating unesterified ALA in human subjects. This method now can be extended to study factors that regulate human whole‐body PUFA synthesis‐secretion in health and disease.     

Review of biodiesel composition, properties, and specifications

Biodiesel is a renewable transportation fuel consisting of fatty acid methyl esters (FAME), generally produced by transesterification of vegetable oils and animal fats. In this review, the fatty acid (FA) profiles of 12 common biodiesel feedstocks were summarized. Considerable compositional variability exists across the range of feedstocks. For example, coconut, palm and tallow contain high amounts of saturated FA; while corn, rapeseed, safflower, soy, and sunflower are dominated by unsaturated FA. Much less information is available regarding the FA profiles of algal lipids that could serve as biodiesel feedstocks. However, some algal species contain considerably higher levels of poly-unsaturated FA than is typically found in vegetable oils.Differences in chemical and physical properties among biodiesel fuels can be explained largely by the fuels’ FA profiles. Two features that are especially influential are the size distribution and the degree of unsaturation within the FA structures. For the 12 biodiesel types reviewed here, it was shown that several fuel properties - including viscosity, specific gravity, cetane number, iodine value, and low temperature performance metrics - are highly correlated with the average unsaturation of the FAME profiles. Due to opposing effects of certain FAME structural features, it is not possible to define a single composition that is optimum with respect to all important fuel properties. However, to ensure satisfactory in-use performance with respect to low temperature operability and oxidative stability, biodiesel should contain relatively low concentrations of both long-chain saturated FAME and poly-unsaturated FAME.     

Hydrogel nanoparticles with covalently linked coomassie blue for brain tumor delineation visible to the surgeon

Delineation of tumor margins is a critical and challenging objective during brain cancer surgery. A tumor-targeting deep-blue nanoparticle-based visible contrast agent is described, which, for the first time, offers in vivo tumor-specific visible color staining. This technology thus enables color-guided tumor resection in real time, with no need for extra equipment or special lighting conditions. The visual contrast agent consists of polyacrylamide nanoparticles covalently linked to Coomassie Blue molecules (for nonleachable blue color contrast), which are surface-conjugated with polyethylene glycol and F3 peptides for efficient in vivo circulation and tumor targeting, respectively.     

Household food insecurity in small municipalities in Northeastern Brazil: a validation study

The State of Paraiba in Northeastern Brazil ranks as the fourth poorest state in the country. The objectives of this study are to conduct the psychometric validation of the Brazilian Household Food Insecurity Scale (EBIA), to assess the household food insecurity (HFI) prevalence, and to identify the association between HFI, poverty and dietary intake in a representative sample of Paraiba’s 14 poorest municipalities (N = 4533). All municipalities included had fewer than 50,000 inhabitants. EBIA had strong internal consistency (Cronbach’s alpha = 0.93 and 0.90 in households with and without children, respectively). The percentage of affirmative responses for each item was inversely associated with household income and the item curves were parallel across socio-economic strata. Rasch modeling indicated that: a) scale items severities followed theoretical expectations, b) all items had an adequate fit to the scale confirming its unidimensionality, and c) items ‘functioned’ similarly across key subpopulation characteristics including: urban/rural; men/women; younger/older; poor/less poor; Bolsa Familia enrollment (yes/no). HFI prevalence was higher in rural than in urban areas (55.5 % vs. 49.9 %, p < 0.0005) and severe food insecurity was substantially higher in rural areas (14.0 % vs. 9.0 %, p < 0.0005). HFI severity was inversely associated with household income, positively associated with daily sugar consumption and inversely associated with daily consumption of bread and nutrient dense foods (fruits, vegetables, and dairy). In conclusion, EBIA had strong internal and external validity at the municipal level. Findings are particularly relevant for Brazil where 89.1 % of municipalities (4,957 out of 5,565 municipalities) have less than 50,000 inhabitants.     

Assessing decision making in young adult romantic relationships.

Romantic relationships among young adults are rich with ambiguity and without a clear, universal progression emphasizing the need for active decision making. Lack of active decision making in romantic relationships can lead to increases in constraints (e.g. pregnancy, shared living space or finances) that promote the continuation of relationships that would have otherwise ended, leading to increased risk of relationship distress. Because there is no available assessment of thoughtfulness regarding relationship decisions, the authors of the present studies report data on the development of one such scale, the Relationship Deciding Scale (RDS). Study 1 (N = 995) reveals the factor structure of the RDS and provides reliability data for the emergent subscales. In Study 2 (N = 963), the obtained three-factor structure (Relationship Confidence, Knowledge of Warning Signs, and Deciding) is tested via confirmatory factor analysis, demonstrates convergent and discriminant validity, and is shown to predict relationship characteristics 14 weeks later. Study 3 (N = 805) shows the sensitivity of the three factors to change through examination of the influence of a semester-long intervention targeted at increasing decision making in relationships. Use of this scale for identifying and intervening with couples or individuals who lack active decision making in relationships may decrease their risk for future relationship distress. (PsycINFO Database Record (c) 2011 APA, all rights reserved)