616 research outputs found

    Reclamation of reactive metal oxides from complex minerals using alkali roasting and leaching- an improved approach to process engineering

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    In nature, the commonly occurring reactive metal oxides of titanium, chromium, aluminium, and vanadium often chemically combine with the transition metal oxides such as iron oxides and form complex minerals. Physico-chemical separation of transition metal oxides from the remaining reactive metal oxides is therefore an important step in the purification of reactive oxide constituents. Each purification step has quite a high energy requirement at present. Current practice in industry yields sulphate and neutralized chloride waste from titanium dioxide enrichment, red mud from bauxite refining, slag and leach residues from vanadium extraction and chromite ore process residue (COPR) from chromate processes. In this review article, a novel alkali-based oxidative roasting and aqueous leaching for the extraction of mineral oxides is explained in the context of the original work of Le Chatelier in 1850, which was unsuccessful in the industrialization of bauxite processing for alumina extraction. However, much later in the 19th century the alkali-based oxidative mineral roasting was successfully developed for industrial scale manufacturing of chromate chemicals, which yields COPR. The crystal chemistry of mineral oxides, namely alumina, titanium dioxide, and chromium oxide in naturally occurring minerals is briefly reviewed in the context of chemical extraction, which is then developed as a model for developing thermodynamic chemical equilibrium principles for analyzing the physical separation and enrichment of such reactive metal oxides by forming water-soluble and water-insoluble alkali complexes. The involvement of the alkali roasting chemistry of non-magnetic titaniferous mineral waste is also reported in the initial separation of rare-earth oxide mixtures for subsequent separation of individual oxides. The paper concludes with a generic approach to process chemistry which minimizes waste generation and therefore helps in reducing the overall process and energy costs. Examples of recovering alkali from high pH solution using carbon dioxide are also demonstrated

    INVESTIGATING HOW PARENTS, WHO GUIDE THEIR PRESCHOOL CHILDREN TOWARDS SPORTS, PERCEIVE SPORTS ACTIVITIES

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    Objectives: The aim of this study was to investigate parents’ expectations about general sport activities for their pre-school children. It is well documented that the awareness of sports knowledge of the parents are essential for the development of healthy life and acquiring a social dimension with a growth of healthy generations. Method: We administrated the ‘’Parents' Expectations of Their Children Questionnaire’’ developed by Keskin (2006). The questionnaire was a Likert type scale from ‘’totally agree’’ to ‘’totally disagree’’ and validity and reliability studies were reported by Keskin as Cronbach’s alpha was 0,86. A total of 125 participants (male; N = 39, Mage=35, 24 ± 5,48 , female; N = 86 and Mage=37,92 ± 6,65) were voluntarily participated from 10 different kinder gardens in Bursa province. The evaluation of the data was analysed with the Chi Square Test. Result: Our results revealed a statistical differences (p < .05) according to the sex groups of parents ‘’I believe my child will gain good eating habits by getting involved with sports activities’’ and age groups of parents; ‘’I believe by getting involved with sport activities, my child will stay away from psychological stress’’. Conclusion: According to parents’ belief and their expectations, attending sports activities for children provides physical, cognitive and social development for them. Developing countries (as well as developed ones) that are aware of the role of the parents on development of human being via sport and exercise activities should take into account their expectations especially in terms of sports policies.  Article visualizations

    Mechanism of periodic height variations along self-aligned VLS-grown planar nanostructures

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    In this study we report in-plane nanotracks produced by molecular-beam-epitaxy (MBE) exhibiting lateral self-assembly and unusual periodic and out-of-phase height variations across their growth axes. The nanotracks are synthesized using bismuth segregation on the GaAsBi epitaxial surface, which results in metallic liquid droplets capable of catalyzing GaAsBi nanotrack growth via the vapor–liquid–solid (VLS) mechanism. A detailed examination of the nanotrack morphologies is carried out employing a combination of scanning electron and atomic force microscopy and, based on the findings, a geometric model of nanotrack growth during MBE is developed. Our results indicate diffusion and shadowing effects play significant roles in defining the interesting nanotrack shape. The unique periodicity of our lateral nanotracks originates from a rotating nucleation “hot spot” at the edge of the liquid–solid interface, a feature caused by the relative periodic circling of the non-normal ion beam flux incident on the sample surface, inside the MBE chamber. We point out that such a concept is divergent from current models of crawling mode growth kinetics and conclude that these effects may be utilized in the design and assembly of planar nanostructures with controlled non-monotonous structure

    J Community Health

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    Alzheimer's disease (AD) is the fourth leading cause of death in Puerto Rico. Using multi-media resources and in-person education may be an effective approach to improve knowledge and awareness of AD. The Un Caf\uc3\ua9 por el Alzheimer program in Puerto Rico incorporates an education component at coffee shops and a social media campaign using Facebook. The current study evaluates this initiative through an analysis of pre/post education survey results and social media content and use. Surveys contained close-ended and open-ended questions to understand participants' perceptions and knowledge about AD. Post-education surveys also included questions related to program satisfaction. Social media analysis of the Facebook community page examined posts from March 1 to September 30, 2015. Descriptive statistics were used to analyze survey and Facebook data. Four education sessions were conducted with a total of 212 participants. Fifty-one of the participants completed both pre- and post-surveys. Following the education program participants reported improved knowledge of risk and protective factors. All participants reported learning new information from the program. There were a total of 250 posts on the Un Caf\uc3\ua9 por el Alzheimer community Facebook page; 168 posts related to AD. The Facebook page reached 294,109 people, with 9963 page likes, 610 comments, 17,780 post clicks, and 3632 shares. There was an average increase of 64.8\uc2\ua0% in number of people reached by the Facebook page following the education sessions. The approach of combining social media resources and in-person education is beneficial to increase public awareness of AD and disseminate health information.U48 DP005000/DP/NCCDPHP CDC HHS/United States2016-10-01T00:00:00Z26983930PMC501143

    Fiber density of collagen grafts impacts rabbit urethral regeneration.

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    There is a need for efficient and "off-the-shelf" grafts in urethral reconstructive surgery. Currently available surgical techniques require harvesting of grafts from autologous sites, with increased risk of surgical complications and added patient discomfort. Therefore, a cost-effective and cell-free graft with adequate regenerative potential has a great chance to be translated into clinical practice. Tubular cell-free collagen grafts were prepared by varying the collagen density and fiber distribution, thereby creating a polarized low fiber density collagen graft (LD-graft). A uniform, high fiber density collagen graft (HD-graft) was engineered as a control. These two grafts were implanted to bridge a 2 cm long iatrogenic urethral defect in a rabbit model. Histology revealed that rabbits implanted with the LD-graft had a better smooth muscle regeneration compared to the HD-graft. The overall functional outcome assessed by contrast voiding cystourethrography showed patency of the urethra in 90% for the LD-graft and in 66.6% for the HD-graft. Functional regeneration of the rabbit implanted with the LD-graft could further be demonstrated by successful mating, resulting in healthy offspring. In conclusion, cell-free low-density polarized collagen grafts show better urethral regeneration than high-density collagen grafts

    Egr1 regulates the coordinated expression of numerous EGF receptor target genes as identified by ChIP-on-chip

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    UV stimulation of prostate cells causes an apoptotic response that is dependent on the zinc finger transcription factor Egr1; downstream targets of Egr1 in this response were identified
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