993 resultados para Ward, John, active 1698-1709


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The phosphine-stabilised gold cluster [Au6(Ph2P-o-tolyl)6](NO3)2 is converted into an active nanocatalyst for the oxidation of benzyl alcohol through low-temperature peroxide-assisted removal of the phosphines, avoiding the high-temperature calcination process. The process was monitored using in-situ X-ray absorption spectroscopy, which revealed that after a certain period of the reaction with tertiary butyl hydrogen peroxide, the phosphine ligands are removed to form nanoparticles of gold which matches with the induction period seen in the catalytic reaction. Density functional theory calculations show that the energies required to remove the ligands from the [Au6Ln]2+ increase significantly with successive removal steps, suggesting that the process does not occur at once but sequentially. The calculations also reveal that ligand removal is accompanied by dramatic re-arrangements in the topology of the cluster core.

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A synthetic version of the metal-regulated gene A (mrgA) promoter from Bacillus subtilis, which in this Gram-positive bacterium is negatively regulated by manganese, iron, cobalt, or copper turned out to promote high level of basal gene expression that is further enhanced by Co(II), Cd(II), Mn(II), Zn(II), Cu(II), or Ni(II), when cloned in the Gram-negative bacterium Cupriavidus metallidurans. Promoter activity was monitored by expression of the reporter gene coding for the enhanced green fluorescent protein (EGFP), and cellular intensity fluorescence was quantified by flow cytometry. Expression levels in C. metallidurans driven by the heterologous promoter, here called pan, ranged from 20- to 53-fold the expression level driven by the Escherichia coli lac promoter (which is constitutively expressed in C. metallidurans), whether in the absence or presence of metal ions, respectively. The pan promoter did also function in E. coli in a constitutive pattern, regardless of the presence of Mn(II) or Fe(II). In conclusion, the pan promoter proved to be a powerful tool to express heterologous proteins in Gram-negative bacteria, especially in C. metallidurans grown upon high levels of toxic metals, with potential applications in bioremediation. Biotechnol. Bioeng. 2010; 107: 469-477. (C) 2010 Wiley Periodicals, Inc.

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The interaction between angiotensin II (AII, DRVYIHPF) and its analogs carrying 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (TOAC) and detergents-negatively charged sodium dodecyl sulfate (SDS) and zwitterionic N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS)-was examined by means of EPR, CD, and fluorescence. EPR spectra of partially active TOAC(1)-AII and inactive TOAC(3)-AII in aqueous solution indicated fast tumbling, the freedom of motion being greater at the N-terminus. Line broadening occurred upon interaction with micelles. Below SDS critical micelle concentration, broader lines indicated complex formation with tighter molecular packing than in micelles. Small changes in hyperfine splittings evinced TOAC location at the micelle-water interface. The interaction with anionic micelles was more effective than with zwitterionic micelles. Peptide-micelle interaction caused fluorescence increase. The TOAC-promoted intramolecular fluorescence quenching was more, pronounced for TOAC(3)-AII because of the proximity between the nitroxide and Tyr(4). CD spectra showed that although both AII and TOAC(1)-AII presented flexible conformations in water, TOAC(3)-AII displayed conformational restriction because of the TOAC-imposed bend (Schreier et al., Biopolymers 2004, 74, 389). In HPS, conformational changes were observed for the labeled peptides at neutral and basic pH. In SDS, all peptides underwent pH-dependent conformational changes. Although the spectra suggested similar folds for All and TOAC(1)-AII, different conformations were acquired by TOAC(3)-AII. The membrane environment has been hypothesized to shift conformational equilibria so as to stabilize the receptor-bound conformation of ligands. The fact that TOAC(3)-AII is unable to acquire conformations similar to those of native AII and partially active TOAC(1)-AII is probably the explanation for its lack of biological activity. (C) 2009 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 525-537, 2009.

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Many school-based research efforts require active parental consent for student participation. Maximizing rates of consent form return and agreement is an important issue, because sample representativeness may be compromised when these rates are low. This article compares two methods for obtaining active parental consent: return of consent forms in the mail versus return by students to their classrooms. The methods were tested in a pilot study of 46 schools (1,058 students), with half of the schools randomly allocated to each of the alternative methods. A hierarchical nonlinear model of consent form return and agreement rates suggests that the student delivered method is more successful at producing higher rates of consent form return and agreement to participate in the study, after controlling for school-level characteristics. The authors discuss the findings and their implications for other researchers engaged in school-based research with adolescents.

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Issue addressed: This paper describes a multimedia campaign implemented in rural New South Wales on a budget smaller than that typical of many published campaigns. The 'To Be Young at Heart- Stay Active Stay Independent' (SASI) campaign was one arm of a multi- strategic program to reduce falls among seniors by promoting physical activity. Methods: This 18-month campaign used social marketing techniques. Central to this campaign was strong formative research, significant use of corporate, community and media partnerships and a detailed, strategic distribution plan. Campaign reach was evaluated by a community intercept survey. Results: A variety of high quality information, education and communication (IEC) resources were developed. Overall, the campaign cost was calculated at $191,000. The actual cost of $42,000 (excluding staff time) was used to generate almost double this amount in sponsorship ($82,000). In the mid-campaign reach survey, 36% recognised the campaign and attributed this to television (58%), newspaper (33%), poster (13%) and bus-back advertising (8%). Of these respondents, 21% reported seeking information about physical activity, 33% reported increased intention to be more active, and 22% reported becoming more active as a result of the campaign. Conclusions: It is possible to develop and deliver a well designed, multimedia campaign on a limited budget by using sound formative research and engaging community and corporate partners to generate sponsorship. An effective distribution strategy is crucial and may require additional partnerships at State or national level.

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Active travel (walking or cycling for transport) is an important contributor to adolescents overall physical activity (PA). This study examines associations between personal, social and environmental variables and active travel to and from school using data from a large observational study to examine active travel in 2961 year 6 and 8 students (48.7% male), aged 10–14 years (M = 11.4, SD = 0.8 yrs) from 231 schools. Participants completed an on-line survey and all reported living within 2 km of school. Data collected included mode of travel to and from school, self-reported health, and PA variables. Social environmental variables included having playgrounds, parks or gyms close by, feeling safe to walk alone, barriers to walking in the neighbourhood (e.g. traffic, no footpaths), peer and family support for PA, existence of sports teams/scout groups, community disorder and perceived neighbourhood safety. Results showed that while more girls (44.3%) than boys (37.4%) walked to school, lower proportions rode bikes (8.3% vs 22.4%) and hence fewer were active travellers overall. Logistic regression models, adjusted for age, location and socio-economic status were conducted for active travel to/from school, separately for boys and girls. Predictors for boys and girls being ‘active travellers’ to/from school included recreational facilities close to home, higher perceived safety of the neighbourhood and higher community disorder. For boys, social support from friends, scout groups available and higher enjoyment of physical activity was also important. These findings suggest areas for future research and may be used to guide strategies to increase active travel to and from school.

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Cloud computing is an emerging evolutionary computing model that provides highly scalable services over highspeed Internet on a pay-as-usage model. However, cloud-based solutions still have not been widely deployed in some sensitive areas, such as banking and healthcare. The lack of widespread development is related to users’ concern that their confidential data or privacy would leak out in the cloud’s outsourced environment. To address this problem, we propose a novel active data-centric framework to ultimately improve the transparency and accountability of actual usage of the users’ data in cloud. Our data-centric framework emphasizes “active” feature which packages the raw data with active properties that enforce data usage with active defending and protection capability. To achieve the active scheme, we devise the Triggerable Data File Structure (TDFS). Moreover, we employ the zero-knowledge proof scheme to verify the request’s identification without revealing any vital information. Our experimental outcomes demonstrate the efficiency, dependability, and scalability of our framework.

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Despite the widely articulated health implications of physical inactivity, declines in youth participation levels, particularly for adolescent girls, have fuelled social and moral panics about the importance of regular physical activity. Recent attempts to explain these participation trends have focused on the institutional and cultural discourses that are drawn on to construct particular identities and social practices connected with sport, physical education and leisure interests. In this paper we report on the findings of data collected through interview and focus group sessions with 138 females ranging from 14 to 16 years of age across six rural and regional communities in the state of Victoria, Australia. Adopting a feminist poststructuralist methodology and drawing on the work of Foucault, we explore the impact that dominant discourse-power relations operating in the context of rural and regional sport and physical education can have in the negotiation of physically active identities for adolescent girls.

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The aim of this study was to evaluate the impact of serious sport and active recreation injury on 12-month physical activity levels. Adults admitted to hospital with sport and active recreation-related injuries, and captured by the Victorian Orthopaedic Trauma Outcomes Registry were recruited to the study. Changes between preinjury and 12 month post-injury physical activity was assessed using the short International Physical Activity Questionnaire (IPAQ). Independent demographic, injury, and hospital variables were assessed for associations with changes in physical activity levels, using multivariate linear regression. A total of 324 patients were recruited, of which 98% were followed up at 12 months. Mean short IPAQ scores decreased from 7650 METS (95% CI: 7180, 8120) preinjury to 3880 METS; (95% CI: 3530, 4250) post-injury, independent of functional recovery. Education level and occupation group were the only variables independently associated with changes in physical activity levels post-injury. These results highlighted that sport and active recreation injuries lead to significant reductions in physical activity levels. Hence, the prevention of sport and active recreation injuries is important when considering promotion of activity at a population level.

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INTRODUCTION: Many American children do not meet recommendations for moderate to vigorous physical activity (MVPA). Although school-based physical education (PE) provides children with opportunities for MVPA, less than half of PE minutes are typically active. The purpose of this study is to estimate the cost effectiveness of a state "active PE" policy implemented nationally requiring that at least 50% of elementary school PE time is spent in MVPA. METHODS: A cohort model was used to simulate the impact of an active PE policy on physical activity, BMI, and healthcare costs over 10 years for a simulated cohort of the 2015 U.S. population aged 6-11 years. Data were analyzed in 2014. RESULTS: An elementary school active PE policy would increase MVPA per 30-minute PE class by 1.87 minutes (95% uncertainty interval [UI]=1.23, 2.51) and cost $70.7 million (95% UI=$51.1, $95.9 million) in the first year to implement nationally. Physical activity gains would cost $0.34 per MET-hour/day (95% UI=$0.15, $2.15), and BMI could be reduced after 2 years at a cost of $401 per BMI unit (95% UI=$148, $3,100). From 2015 to 2025, the policy would cost $235 million (95% UI=$170 million, $319 million) and reduce healthcare costs by $60.5 million (95% UI=$7.93 million, $153 million). CONCLUSIONS: Implementing an active PE policy at the elementary school level could have a small impact on physical activity levels in the population and potentially lead to reductions in BMI and obesity-related healthcare expenditures over 10 years.

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Background Disability, mortality and healthcare burden from fractures in older people is a growing problem worldwide. Observational studies suggest that aspirin may reduce fracture risk. While these studies provide room for optimism, randomised controlled trials are needed. This paper describes the rationale and design of the ASPirin in Reducing Events in the Elderly (ASPREE)-Fracture substudy, which aims to determine whether daily low-dose aspirin decreases fracture risk in healthy older people. Methods ASPREE is a double-blind, randomised, placebo-controlled primary prevention trial designed to assess whether daily active treatment using low-dose aspirin extends the duration of disability-free and dementia-free life in 19 000 healthy older people recruited from Australian and US community settings. This substudy extends the ASPREE trial data collection to determine the effect of daily low-dose aspirin on fracture and fall-related hospital presentation risk in the 16 500 ASPREE participants aged ≥70 years recruited in Australia. The intervention is a once daily dose of enteric-coated aspirin (100 mg) versus a matching placebo, randomised on a 1:1 basis. The primary outcome for this substudy is the occurrence of any fracture-vertebral, hip and non-vert-non-hip-occurring post randomisation. Fall-related hospital presentations are a secondary outcome. Discussion This substudy will determine whether a widely available, simple and inexpensive health intervention-aspirin-reduces the risk of fractures in older Australians. If it is demonstrated to safely reduce the risk of fractures and serious falls, it is possible that aspirin might provide a means of fracture prevention.

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Background: To investigate the impact of playing sports Active Video Games on children's actual and perceived object control skills. Methods: Intervention children played Active Video Games for 6. weeks (1. h/week) in 2012. The Test of Gross Motor Development-2 assessed object control skill. The Pictorial Scale of Perceived Movement Skill Competence assessed perceived object control skill. Repeated measurements of object control and perceived object control were analysed for the whole sample, using linear mixed models, which included fixed effects for group (intervention or control) and time (pre and post) and their interaction. The first model adjusted for sex only and the second model also adjusted for age, and prior ball sports experience (yes/no). Seven mixed-gender focus discussions were conducted with intervention children after programme completion. Results: Ninety-five Australian children (55% girls; 43% intervention group) aged 4 to 8. years (M 6.2, SD 0.95) participated. Object control skill improved over time (p=0.006) but there was no significant difference (p=0.913) between groups in improvement (predicted means: control 31.80 to 33.53, SED=0.748; intervention 30.33 to 31.83, SED=0.835). A similar result held for the second model. Similarly the intervention did not change perceived object control in Model 1 (predicted means: control: 19.08 to 18.68, SED=0.362; intervention 18.67 to 18.88, SED=0.406) or Model 2. Children found the intervention enjoyable, but most did not perceive direct equivalence between Active Video Games and 'real life' activities. Conclusions: Whilst Active Video Game play may help introduce children to sport, this amount of time playing is unlikely to build skill.