113 research outputs found

    Dual function filtration and catalytic breakdown of organic pollutants in wastewater using ozonation with titania and alumina membranes

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    Water recycling via treatment from industrial and/or municipal waste sources is one of the key strategies for resolving water shortages worldwide. Polymer membranes are effective at improving the water quality essential for recycling, but depend on regular cleaning and replacement. Pure ceramic membranes can reduce the cleaning need and last significantly longer in the same applications while possessing the possibility of operating in more aggressive environments not suitable for polymers. In the current work, filtration using a tubular ceramic membrane (�-Al2O3 or TiO2) was combined with ozonation to remove organic compounds present in a secondary effluent to enhance key quality features of the water (colour and total organic carbon, TOC) for its potential reuse. ‘Bare’ commercial �-Al2O3 filters (pore size ∼0.58 �m) were tested as a microfiltration membrane and compared with the more advanced catalytically active TiO2 layer that was formed by the sol–gel method. The presence of anatase with a 4 nm pore size at the membrane surface was confirmed by X-ray diffraction (XRD) and N2 adsorption. Filtration of the effluent over a 2 h period led to a reduction in flux to 45% and 60% of the initial values for the �-alumina and TiO2 membrane, respectively. However, a brief dose (2 min) of ozone at the start of the run resulted in reductions to only 70% of the initial flux for both membranes. It is likely that the oxide’s functional property facilitated the formation of hydroxyl (OH•) or other radicals on the membrane surface from ozone decomposition which targeted the breakdown of organic foulants thus inhibiting their deposition. Interestingly, the porous structure therefore acted in a synergistic, dual function mode to physically separate the particulates while also catalytically breaking down organic matter. The system also greatly improved the efficiency of membrane filtration for the reduction of colour, A254 (organics absorption at the wavelength of 254 nm) and TOC. The best performance came from combined ozonation (2 min ozonation time with an estimated applied ozone dose of 8 mg L−1) with the TiO2 membrane, which was able to reduce colour by 88%, A254 by 75% and TOC by 43%. It is clearly evident that a synergistic effect occurs with the process combination of ozonation and ceramic membrane filtration demonstrating the practical benefit of combining ceramic membrane filtration with conventional water ozonation

    Alberta Diabetes and Physical Activity Trial (ADAPT): A randomized theory-based efficacy trial for adults with type 2 diabetes - rationale, design, recruitment, evaluation, and dissemination

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    Background: The primary aim of this study was to compare the efficacy of three physical activity (PA) behavioural intervention strategies in a sample of adults with type 2 diabetes. Method/Design: Participants (N = 287) were randomly assigned to one of three groups consisting of the following intervention strategies: (1) standard printed PA educational materials provided by the Canadian Diabetes Association [i.e., Group 1/control group)]; (2) standard printed PA educational materials as in Group 1, pedometers, a log book and printed PA information matched to individuals' PA stage of readiness provided every 3 months (i.e., Group 2); and (3) PA telephone counseling protocol matched to PA stage of readiness and tailored to personal characteristics, in addition to the materials provided in Groups 1 and 2 (i.e., Group 3). PA behaviour measured by the Godin Leisure Time Exercise Questionnaire and related social-cognitive measures were assessed at baseline, 3, 6, 9, 12 and 18-months (i.e., 6-month follow-up). Clinical (biomarkers) and health-related quality of life assessments were conducted at baseline, 12-months, and 18-months. Linear Mixed Model (LMM) analyses will be used to examine time-dependent changes from baseline across study time points for Groups 2 and 3 relative to Group 1. Discussion: ADAPT will determine whether tailored but low-cost interventions can lead to sustainable increases in PA behaviours. The results may have implications for practitioners in designing and implementing theory-based physical activity promotion programs for this population

    Going Through the Rites of Passage: Timing and Transition of Menarche, Childhood Sexual Abuse, and Anxiety Symptoms in Girls

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    Menarche is a discrete, transitional event that holds considerable personal, social, biological, and developmental significance. The present longitudinal study examined both the transition and timing of menarche on the trajectory of anxiety in girls with histories of childhood maltreatment (N = 93; 63% European American, 14% multiracial, 10% Latino, 9% African American, and 4% Native American). We hypothesized that because menarche is a novel, unfamiliar experience, girls would show greater anxiety around the time of menarche. The anxiety-provoking nature of menarche may be accentuated among earlier-maturing girls and girls with histories of childhood sexual abuse. Results indicated that earlier-maturing girls were more anxious in the pre- and peri-menarche periods than their later-maturing peers; however, their anxiety declined after menarche. Childhood sexual abuse was associated with heightened anxiety throughout this transition. The developmental significance of the timing and transition of menarche in relation to childhood sexual abuse and anxiety is discussed

    Wave-swept coralliths of Saba Bank, Dutch Caribbean

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    Plasmodium falciparum malaria and invasive bacterial co-infection in young African children: the dysfunctional spleen hypothesis

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    Social participation and subjective well-being of long-term unemployed:why is paid work so hard to substitute for?

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    In a study of SWB among 948 Dutch long-term unemployed, the two main questions were (I) do long-term unemployed learn To adjust, i.e. does the negative effect on SWB wear off over unemployment duration?; and (2) does social participation help adjustment and restoration of SWB?The effect of unemployment on SWB was negative, as expected, but was unrelated to unemployment duration. Neither income nor social participation explained variation in SWB to a substantive degree. Apparently, unemployment deprives people of an important source of well-being which is difficult to compensate.The proposed explanation for these findings comes from Social Production Function theory (Lindenberg 1986, 1996). SPF-theory specifies an instrumental hierarchy of universal human goals. It provides a systematic tool to study the processes by which people realize these goals, given the restrictions and resources they face. We argue that SPF-theory, by giving insight in the process of substitution</p
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