Association between regular participation in sports and leisure time behaviors in Brazilian adolescents: A cross-sectional study

<p>Abstract</p> <p>Background</p> <p>The belief that adolescents engaged in sports increase their overall physical activity level while simultaneously decreasing physical inactivity has been the foundation of many intervention programs in developing countries. The aim of this study was to analyze the association between regular participation in sports and both active behaviors and TV viewing during leisure time.</p> <p>Methods</p> <p>A total of 1752 Brazilian adolescents (812 = male and 940 = female) participated in this study. Regular participation in sports, as well as active behaviors (exemplified by walking or cycling) and TV viewing during leisure time were assessed by means of a questionnaire. The chi-square test analyzed the association between sports practice and leisure time behaviors, and the Poisson regression with robust variance indicated the magnitude of these associations.</p> <p>Results</p> <p>The prevalence of regular participation in sports was 14.8% (95% confidence interval 13.2% to 16.5%). After adjustment for all confounders, participation in sports was associated with, at the highest frequency, cycling (PR = 2.55 [1.80–3.60]) and walking (PR = 2.69 [1.98–3.64]) during leisure time. However, there was not an association between the participation in sports and frequency of TV viewing (PR = 1.28 [0.81–2.02]).</p> <p>Conclusion</p> <p>This study presented data indicating that the regular participation in sports is positively associated with a higher frequency of physically active behaviors during leisure time. However, the results did not support the hypothesis that the engagement in sports necessarily decreases leisure time spent in TV viewing.</p

Hindered rolling and friction anisotropy in supported carbon nanotubes

Carbon nanotubes (CNTs) are well known for their exceptional thermal, mechanical and electrical properties. For many CNT applications it is of the foremost importance to know their frictional properties. However, very little is known about the frictional forces between an individual nanotube and a substrate or tip. Here, we present a combined theoretical and experimental study of the frictional forces encountered by a nanosize tip sliding on top of a supported multiwall CNT along a direction parallel or transverse to the CNT axis. Surprisingly, we find a higher friction coefficient in the transverse direction compared with the parallel direction. This behaviour is explained by a simulation showing that transverse friction elicits a soft 'hindered rolling' of the tube and a frictional dissipation that is absent, or partially absent for chiral CNTs, when the tip slides parallel to the CNT axis. Our findings can help in developing better strategies for large-scale CNT assembling and sorting on a surface.Comment: 8 pages, 5 figure

Frequency of symptoms, determinants of severe symptoms, validity of and cut-off score for Menopause Rating Scale (MRS) as a screening tool: A cross-sectional survey among midlife Nepalese women

<p>Abstract</p> <p>Background</p> <p>Majority of Nepalese women live in remote rural areas, where health services are not easily accessible. We determined the validity of Menopause Rating Scale (MRS) as a screening tool for identification of women with severe menopausal symptoms and cut-off MRS score for referral.</p> <p>Methods</p> <p>A cross-sectional survey was carried out between February and August, 2008. Trained health workers administered MRS and a questionnaire to 729 women (40 to 65 years) attending health screening camps in Kaski district of Western Development Region of Nepal. Information about demographics, menopausal status, and use of hormone replacement therapy (HRT), chronic disease, self-perceived general health and reproductive history was also collected. Menopausal status was classified according to the Staging of Reproductive Ageing Workshop (STRAW). We calculated rates of menopausal symptoms, sensitivity, and specificity and likelihood ratios of MRS scores for referral to a gynaecologist. We also carried out multivariate analyses to identify the predictors for referral to a gynaecologist for severe symptoms.</p> <p>Results</p> <p>A total 729 women were interviewed. Mean age at menopause was 49.9 years (SD 5.6). Most frequently reported symptoms were, sleeping problems (574, 78.7%), physical and mental exhaustion (73.5%), hot flushes (508, 69.7%), joint and muscular discomfort (500, 68.6%) and dryness of vagina (449, 61.6%). Postmenopausal women (247, 33.9%) and perimenopausal (215, 29.5%) women together experienced significantly higher prevalence of all symptoms than the premenopausal (267, 36.6%) women. MRS score of ≥16 had highest ratio for (sensitivity + specificity)/2. Women who reported urogenital symptoms [OR 5.29, 95% CI 2.59, 10.78], and self perceived general health as poor [OR 1.29, 95% CI 1.11, 1.53] were more likely to be referred to a gynaecologist for severe menopausal symptoms. While women reporting somatic [OR 0.72, 95% CI 0.63, 0.82] and psychological [OR 0.86, 95% CI 0.74, 0.99] symptoms were less likely to be referred.</p> <p>Conclusion</p> <p>MRS may be used as a screening tool at a cut-off score of ≥16 with least misclassification rate. However, its utility may be limited by woman's general health status and occurrence of urogenital symptoms.</p

Singular Location and Signaling Profile of Adenosine A2A-Cannabinoid CB1 Receptor Heteromers in the Dorsal Striatum

The dorsal striatum is a key node for many neurobiological processes such as motor activity, cognitive functions, and affective processes. The proper functioning of striatal neurons relies critically on metabotropic receptors. Specifically, the main adenosine and endocannabinoid receptors present in the striatum, ie, adenosine A2A receptor (A2AR) and cannabinoid CB1 receptor (CB1R), are of pivotal importance in the control of neuronal excitability. Facilitatory and inhibitory functional interactions between striatal A2AR and CB1R have been reported, and evidence supports that this cross-talk may rely, at least in part, on the formation of A2AR-CB1R heteromeric complexes. However, the specific location and properties of these heteromers have remained largely unknown. Here, by using techniques that allowed a precise visualization of the heteromers in situ in combination with sophisticated genetically-modified animal models, together with biochemical and pharmacological approaches, we provide a high resolution expression map and a detailed functional characterization of A2AR-CB1R heteromers in the dorsal striatum. Specifically, our data unveil that the A2AR-CB1R heteromer (i) is essentially absent from corticostriatal projections and striatonigral neurons, and, instead, is largely present in striatopallidal neurons, (ii) displays a striking G protein-coupled signaling profile, where co-stimulation of both receptors leads to strongly reduced downstream signaling, and (iii) undergoes an unprecedented dysfunction in Huntington’s disease, an archetypal disease that affects striatal neurons. Altogether, our findings may open a new conceptual framework to understand the role of coordinated adenosine-endocannabinoid signaling in the indirect striatal pathway, which may be relevant in motor function and neurodegenerative diseases

The Efficacy of Trastuzumab in Animal Models of Breast Cancer:A Systematic Review and Meta-Analysis

BACKGROUND:Breast cancer is the most frequent cancers and is the second leading cause of cancer death among women. Trastuzumab is an effective treatment, the first monoclonal antibody directed against the human epidermal growth factor receptor 2 (HER2). To inform the development of other effective treatments we report summary estimates of efficacy of trastuzumab on survival and tumour volume in animal models of breast cancer. METHODS:We searched PubMed and EMBASE systematically to identify publications testing trastuzumab in animal models of breast cancer. Data describing tumour volume, median survival and animal features were extracted and we assessed quality using a 12-item checklist. We analysed the impact of study design and quality and evidence for publication bias. RESULTS:We included data from 83 studies reporting 169 experiments using 2076 mice. Trastuzumab treatment caused a substantial reduction in tumour growth, with tumours in treated animals growing to 32.6% of the volume of tumours in control animals (95%CI 27.8%-38.2%). Median survival was prolonged by a factor of 1.45 (1.30-1.62). Many study design and quality features accounted for between-study heterogeneity and we found evidence suggesting publication bias. CONCLUSION:We have found trastuzumab to be effective in animal breast cancer models across a range of experimental circumstances. However the presence of publication bias and a low prevalence of measures to reduce bias provide a focus for future improvements in preclinical breast cancer research