180 research outputs found

    Ultimate behaviour of steel braces under cyclic loading

    Get PDF
    Under significant seismic loading conditions, the response of concentrically braced frames largely depends on the behaviour of the diagonal braces, which represent the key energy dissipating zones. Although the hysteretic response of steel braces under cyclic axial loading has been examined in previous studies, there is a need for further assessments that focus on quantifying failure. This paper describes the development of detailed finite-element models of hollow sections subjected to cyclic axial loading. The effects of initial imperfections and cyclic hardening are taken into consideration and the models are validated against data from 19 tests. A method to predict the fracture life of bracing members under cyclic loading is also described. Using the numerical models, parametric studies are undertaken to assess the influence of global and local slendernesses on the performance of the braces – both are found to affect the occurrence and severity of local buckling under cyclic loading, which causes high localised strains at the corner areas of sections, leading to fatigue fracture. A predictive equation addressing the coexisting influence of global slenderness and local slenderness on displacement ductility is presented. The observations in the current study are compared with conclusions from other experimental programmes, and the discrepancy between the findings is discussed

    Patient experience of nasal obstruction and its clinical assessment

    Get PDF
    BACKGROUND: The correlation between objective and subjective nasal obstruction is poor, and dissatisfaction rates after surgery for nasal obstruction are high. Accordingly, novel assessment techniques may be required. This survey aimed to determine patient experience and preferences for the measurement of nasal obstruction. METHOD: Prospective survey of rhinology patients. RESULTS: Of 72 questionnaires distributed, 60 were completed (response rate of 83 per cent). Obstruction duration (more than one year) (χ2 = 13.5, p = 0.00024), but not obstruction severity, affected willingness to spend more time being assessed. Questionnaires (48 per cent) and nasal inspiratory peak flow measurement (53 per cent) are the most commonly used assessment techniques. Forty-nine per cent of participants found their assessment unhelpful in understanding their obstruction. Eighty-two per cent agreed or strongly agreed that a visual and numerical aid would help them understand their blockage. CONCLUSION: Many patients are dissatisfied with current assessment techniques; a novel device with visual or numerical results may help. Obstruction duration determines willingness to undergo longer assessment

    A UK survey of current ENT practice in the assessment of nasal patency

    Get PDF
    Nasal obstruction is a common ENT complaint; however, decisions on its management are challenging, with high rates of dissatisfaction following surgery. This study investigated the practice of UK clinicians in the evaluation of nasal patency. Seventy-eight UK-based rhinologists were surveyed at the 2015 British Academic Conference in Otolaryngology. Clinical history and examination are almost universally used to evaluate nasal blockage. The most commonly used test was the nasal misting pattern (73 per cent), followed by peak nasal inspiratory flow (19 per cent). The Sino-Nasal Outcome Test 22 or 23 was utilised by 29 per cent of respondents. Sixty-three per cent of respondents reported that a lack of equipment was the principle reason for not using objective measures, followed by time constraints and a lack of correlation with symptom scores. British clinicians rely on clinical skills to evaluate nasal blockage. There is a desire for a simple, non-invasive device that objectively measures airflow for nasal breathing during physiological resting and correlates with subjective symptom scores

    Prosumers in a digital multiverse: An investigation of how WeChat is affecting Chinese citizen journalism

    Get PDF
    WeChat is China’s most popular multi-purpose messaging and social media application and has been gaining popularity globally since its first release in 2011. In this article, we examine how the use of WeChat is affecting digitally-enabled citizen journalism in China. To achieve that purpose, we gathered data from 3 focus-group interviews with Chinese WeChat users. The findings suggest that WeChat’s integration of multiple communicative networks renders it a multiversal space where citizen journalistic practice can transverse across public, semi-public, and private spheres. The diverse communicative affordances of WeChat could facilitate ‘metavoicing’ practice as a form of citizen journalism, and enable news production and consumption to converge. Consequently, users’ experiences of news and news story lifecycles have been affected. WeChat offers both opportunities and challenges to the practice of citizen journalism: it is a space where information exchange could be constantly monitored, where the tone of current affairs coverage is often sensationalized, and where the reliability of content can be difficult to discern

    Design of the sex hormones and physical exercise (SHAPE) study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Physical activity has been associated with a decreased risk for breast cancer. The biological mechanismn(s) underlying the association between physical activity and breast cancer is not clear. Most prominent hypothesis is that physical activity may protect against breast cancer through reduced lifetime exposure to endogenous hormones either direct, or indirect by preventing overweight and abdominal adiposity. In order to get more insight in the causal pathway between physical activity and breast cancer risk, we designed the <it>Sex Hormones and Physical Exercise (SHAPE) </it>study. Purpose of SHAPE study is to examine the effects of a 1-year moderate-to-vigorous intensity exercise programme on endogenous hormone levels associated with breast cancer among sedentary postmenopausal women and whether the amount of total body fat or abdominal fat mediates the effects.</p> <p>Methods/Design</p> <p>In the SHAPE study, 189 sedentary postmenopausal women, aged 50–69 years, are randomly allocated to an intervention or a control group. The intervention consists of an 1-year moderate-to-vigorous intensity aerobic and strenght training exercise programme. Partcipants allocated to the control group are requested to retain their habitual exercise pattern. Primary study parameters measured at baseline, at four months and at 12 months are: serum concentrations of endogenous estrogens, endogenous androgens, sex hormone binding globuline and insuline. Other study parameters include: amount of total and abdominal fat, weight, BMI, body fat distribution, physical fitness, blood pressure and lifestyle factors.</p> <p>Discussion</p> <p>This study will contribute to the body of evidence relating physical activity and breast cancer risk and will provide insight into possible mechanisms through which physical activity might be associated with reduced risk of breast cancer in postmenopausal women.</p> <p>Trial registration</p> <p>NCT00359060</p

    Cyr61/CCN1 Displays High-Affinity Binding to the Somatomedin B 1–44 Domain of Vitronectin

    Get PDF
    OV) family of extracellular-associated (matricellular) proteins that present four distinct functional modules, namely insulin-like growth factor binding protein (IGFBP), von Willebrand factor type C (vWF), thrombospondin type 1 (TSP), and C-terminal growth factor cysteine knot (CT) domain. While heparin sulphate proteoglycans reportedly mediate the interaction of Cyr61 with the matrix and cell surface, the role of other extracellular associated proteins has not been revealed. at high concentrations attenuate Cyr61 binding to immobilized VTNC, while monomeric VTNC was ineffective. Therefore, immobilization of VTNC exposes cryptic epitopes that recognize Cyr61 with high affinity, as reported for a number of antibodies, β-endorphin, and other molecules. domain suggests that VTNC represent a point of anchorage for CCN family members to the matrix. Results are discussed in the context of the role of CCN and VTNC in matrix biology and angiogenesis

    Physical activity, sedentary time and physical capability in early old age: British birth cohort study.

    Get PDF
    PURPOSE: To investigate the associations of time spent sedentary, in moderate-to-vigorous-intensity physical activity (MVPA) and physical activity energy expenditure (PAEE) with physical capability measures at age 60-64 years. METHODS: Time spent sedentary and in MVPA and, PAEE were assessed using individually calibrated combined heart rate and movement sensing among 1727 participants from the MRC National Survey of Health and Development in England, Scotland and Wales as part of a detailed clinical assessment undertaken in 2006-2010. Multivariable linear regression models were used to examine the cross-sectional associations between standardised measures of each of these behavioural variables with grip strength, chair rise and timed up-&-go (TUG) speed and standing balance time. RESULTS: Greater time spent in MVPA was associated with higher levels of physical capability; adjusted mean differences in each capability measure per 1 standard deviation increase in MVPA time were: grip strength (0.477 kg, 95% confidence interval (CI): 0.015 to 0.939), chair rise speed (0.429 stands/min, 95% CI: 0.093 to 0.764), standing balance time (0.028 s, 95% CI: 0.003 to 0.053) and TUG speed (0.019 m/s, 95% CI: 0.011 to 0.026). In contrast, time spent sedentary was associated with lower grip strength (-0.540 kg, 95% CI: -1.013 to -0.066) and TUG speed (-0.011 m/s, 95% CI: -0.019 to -0.004). Associations for PAEE were similar to those for MVPA. CONCLUSION: Higher levels of MVPA and overall physical activity (PAEE) are associated with greater levels of physical capability whereas time spent sedentary is associated with lower levels of capability. Future intervention studies in older adults should focus on both the promotion of physical activity and reduction in time spent sedentary.This work was supported by the UK Medical Research Council (U120063239, U123092720, MC_UU_12019/1, MC_UU_12019/4, MC_UU_12015/3, and MC_UU_12015/4).This is the final published version. It first appeared at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0126465
    • …
    corecore