Reactivity and Pozzolanic Properties of Biomass Ashes Generated by Wheat and Soybean Straw Combustion

A sustainable use of locally available wastes from agriculture as supplementary cementitious materials (SCMs) is an alternative solution for the prevention of excessive raw material usage, reduction of CO₂ emission and cost-effective concrete production. This paper studies the reactivity of non-traditional waste SCMs: Wheat straw ash (WSA), mixture of wheat and soybean straw ash (WSSA) and soybean straw ash (SSA), which are abundant as agricultural by-products in Serbia. The chemical evaluation using XRF technique, thermal analysis (TGA/DSC), XRD and FTIR methods were performed along with physical properties tests to investigate the feasibility of utilizing biomass ashes as cement substitutes. The obtained results demonstrate a high pozzolanic activity of WSA, which is attributed to a high reactive silica content of the ash and its satisfactory level of fineness. A wider hump in XRD pattern of WSA compared to WSSA and SSA confirmed that it abounds in amorphous (reactive) phase. The insufficient activity index of soybean-based biomass ashes, characterized with a low silica content, was improved by additional grinding and/or blending with amorphous silica-rich material. This points out the mechanical activation, i.e., grinding procedure, and chemical activation, i.e., modification of the chemical composition, as techniques efficient at producing pozzolanic materials from biomass wastes. Tested biomass ashes are characterized with negligible leaching values of heavy metals, thereby satisfying eco-friendly principles of SCM utilization. The application of biomass ashes as SCMs leads to substantial cost savings, as well as benefits to the environment, such as lower consumption of cement, reduction of CO₂ emissions during the production of cement and sustainable waste management.     

Altruism motivates participation in a therapeutic HIV vaccine trial (CTN 173)

This is the first study examining motivation to participate in an HIV therapeutic vaccine trial of Remune and ALVAC. Trial participants (N=49) completed psychological measures at baseline. While 69% reported some personal risk in participating, 100% felt hopeful for societal benefits. Trial participants also reported high levels of existential well-being (e.g., "I believe there is some real purpose for my life"). Results suggest that HIV therapeutic vaccine trial participants are highly motivated by altruism and that participating in research may contribute meaning to living with HIV. Fostering altruism and responsibly promoting the societal benefits of research may facilitate trial participation.     

Chronic Ethanol Consumption Results in Atypical Liver Injury in Copper/Zinc Superoxide Dismutase Deficient Mice

Background: Ethanol metabolism increases production of reactive oxygen species, including superoxide () in the liver, resulting in significant oxidative stress, which causes cellular damage. Superoxide dismutase (SOD) is an antioxidant enzyme that converts superoxide to less toxic intermediates, preventing accumulation. Because the absence of SOD would confer less resistance to oxidative stress, we determined whether damage to hepatic proteolytic systems was greater in SOD^?/? than in SOD^+/+ mice after chronic ethanol feeding. Methods: Female wild‐type (SOD^+/+) and Cu/Zn‐SOD knockout (SOD^?/?) mice were pair‐fed ethanol and control liquid diets for 24 days, after which liver injury was assessed. Results: Ethanol‐fed SOD^?/? mice had 4‐fold higher blood ethanol, 2.8‐fold higher alanine aminotransferase levels, 20% higher liver weight, a 1.4‐fold rise in hepatic protein levels, and 35 to 70% higher levels of lipid peroxides than corresponding wild‐type mice. While wild‐type mice exhibited fatty liver after ethanol administration, SOD^?/? mice showed no evidence of ethanol‐induced steatosis, although triglyceride levels were elevated in both groups of knockout mice. Ethanol administration caused no significant change in proteasome activity, but caused lysosomal leakage in livers of SOD^?/? mice but not in wild‐type mice. Alcohol dehydrogenase activity was reduced by 50 to 60% in ethanol‐fed SOD^?/? mice compared with all other groups. Additionally, while ethanol administration induced cytochrome P450 2E1 (CYP2E1) activity in wild‐type mice, it caused no such induction in SOD^?/? mice. Unexpectedly, ethanol feeding significantly elevated total and mitochondrial levels of glutathione in SOD knockout mice compared with wild‐type mice. Conclusion: Ethanol‐fed SOD^?/? mice exhibited lower alcohol dehydrogenase activity and lack of CYP2E1 inducibility, thereby causing decreased ethanol metabolism compared with wild‐type mice. These and other atypical responses to ethanol, including the absence of ethanol‐induced steatosis and enhanced glutathione levels, appear to be linked to enhanced oxidative stress due to lack of antioxidant enzyme capacity.     

HIV Prevention in Action on the Football Field: The Whizzkids United Program in South Africa

The Africaid Trust is a grassroots South African non-profit organization that engages youth in HIV prevention by harnessing the popularity of football (i.e. soccer). WhizzKids United, the organization’s primary program, operates a 12-week program in elementary schools in Pietermaritzburg, South Africa, which aims to impart knowledge and life skills critical to HIV prevention. The goal of this research was to compare elementary school youth who received the program to youth who only received traditional classroom-based HIV education on health behaviors and HIV-related knowledge and stigma. A secondary objective was to evaluate HIV knowledge, sexual behaviors, attitudes towards HIV and health care seeking behaviors among South African youth in grades 9–12. Elementary students who participated in the program reported greater HIV knowledge and lower HIV stigma (p < .001) than those who had not. The majority of youth in grades 9–12 report having sexual relations (55.6 %), despite low levels of HIV testing (29.9 %) in this high HIV prevalence region of South Africa. The results highlight the importance of supporting community-based HIV educational initiatives that engage high-risk youth in HIV prevention and the need for youth-friendly health services.     

Impaired astrocytic extracellular matrix distribution under congenital hypothyroidism affects neuronal development in vitro

Astrocytes clearly play a role in neuronal development. An indirect mechanism of thyroid hormone (T3) in the regulation of neuronal development mediated by astrocytes has been proposed. T3 alters the production and organization of the extracellular matrix (ECM) proteins and proteoglycans, producing a high‐quality substrate for neuronal differentiation. The present study investigated the effect of hypothyroidism on the astrocyte production of fibronectin (FN) and laminin (LN) as well as their involvement in neuronal growth and neuritogenesis. Our results demonstrated that the amount of both FN and LN were significantly reduced in cultures of hypothyroid astrocytes from rat cerebellum compared with normal cells. This effect was accompanied by reduced numbers of neurons and neuritogenesis. Similarly, the proportions of neurons and neurons with neurites were reduced in cultures on ECM prepared from hypothyroid astrocytes in comparison with normal cells. The proportion of both normal and hypothyroid neurons is strongly reduced in astrocyte ECM compared with cocultures on astrocyte monolayers, suggesting that extracellular factors other than ECM proteins are involved in this process. Moreover, treatment of hypothyroid astrocytic cultures with T3 restored the area of both FN and LN immunostaining to normal levels and partially reestablished neuronal survival and neuritogenesis. Taken together, our results demonstrated that hypothyroidism involves impairment of the astrocytic microenvironment and affects the production of ECM proteins. Thus, hypothyroidism is implicated in impaired neuronal development. © 2010 Wiley‐Liss, Inc.     

An attachment insecurity model of negative affect among women seeking treatment for an eating disorder

The purpose of this study was to propose and test a model of attachment insecurity in a clinical sample of 268 eating disordered women. Structural relationships among attachment insecurity, BMI, perceived pressure to diet, body dissatisfaction, restrained eating, and negative affect were assessed. A heterogeneous sample of treatment seeking women with a diagnosed eating disorder completed psychometric tests prior to receiving treatment. The data were analysed using structural equation modeling. Fit indices indicated that the hypothesized model fit adequately to the data. Although cross-sectional in nature, the data suggested that attachment insecurity may lead to negative affect. As well, attachment insecurity may lead to body dissatisfaction, which in turn may lead to restrained eating among women with eating disorders. Attachment insecurity could be a possible vulnerability factor for the development of eating disorder symptoms among women.