Prospective associations of different contexts of physical activity with psychological distress and well-being among middle-aged adults: an analysis of the 1970 British Cohort Study

Background: Our aim was to investigate whether different types and social contexts of physical activity (PA) participation are prospectively associated with psychological distress and well-being among middle-aged adults. / Methods: Data from the 1970 British Cohort Study was used (N=5,144-2,733 women). At age 42y, participants reported their type of leisure-time PA, which was classified as individual PA or group PA (exposure). At age 46y, participants reported co-primary outcomes: psychological distress (Malaise Inventory) and well-being (Warwick-Edinburgh scale). Highest academic achievement, employment status, country of interview, baseline values of psychological distress and well-being, smoking, alcohol use, TV-viewing and total physical activity at 42y were used as covariates. Main analyses included linear regression stratifying by sex. / Results: Jogging, cross-country, road-running (both sexes) as well as team sports (men) were associated with higher well-being. Health, fitness, gym or conditioning activities and jogging, cross-country (women), road-running (women) and team sports (men) were associated with lower psychological distress. Participation in both individual and group PA were associated with lower psychological distress and higher well-being for both sexes in crude models. However, adjusted models revealed that only group PA was associated with lower psychological distress (B: -0.106; 95%CI:-0.188 to -0.025) and higher well-being (0.835; 0.050 to 1.619) among men but not women. In the sensitivity analysis, group PA was associated with higher well-being (0.855; 0.094 to 1.616) when compared with individual PA among men. Group PA was not associated with psychological distress among both sexes and well-being among women when compared with individual PA. / Conclusion: Group PA was prospectively associated with lower psychological distress and higher well-being among men but not females. Future PA interventions could focus on group activities for males. Further research to understand the relationship between individual/group PA and mental health is required in females

A cure modelling study of an unsaturated polyester resin system for the simulation of curing of fibre-reinforced composites during the vacuum infusion process

This study presents the cure kinetics and cure modelling of an ambient curing unsaturated polyester (UP) resin system for its cure simulation in the vacuum infusion (VI) process. The curing of the UP resin system was investigated using differential scanning calorimetry (DSC). The dynamic DSC test measurements were conducted to find out the ultimate heat of reaction and enable experimental conversion determination for the isothermal curing. The empirical autocatalytic cure kinetics model incorporating the Arrhenius law represented the cure behaviour. The results of the cure kinetics study, the cure model, the material properties and the boundary conditions were the inputs in PAM-RTM software for the simulation of the degree of cure and the exothermic temperature during the infusion and the room temperature curing stages. The simulation results were compared with experimentally measured data. A vacuum infusion (VI) experiment involving a non-crimp glass fibre preform was performed in order to monitor the curing using thermocouples and validate the temperature simulation result. It was shown that the degree of cure and the exothermic temperature of a room temperature curing thermoset resin system during the VI process could be predicted through the steps of this study

Does physical activity moderate the association between device-measured sedentary time patterns and depressive symptoms in adults?

OBJECTIVES: To investigate the association between sedentary time (ST) patterns and depressive symptoms, and whether moderate-to-vigorous physical activity (MVPA) can moderate this association. METHODS: This cross-sectional study included a representative sample of 243 adults (mean age 41.8616.7 years, 56.4% women) from a city in Southeast Brazil. Depressive symptoms were estimated through the Hospital Anxiety and Depression Scale (HADS). ST patterns (i.e., number of breaks, mean length of sedentary bouts, and number of long sedentary bouts), total ST, and MVPA were assessed using accelerometers. RESULTS: Poisson regression models revealed associations of total ST (b = 0.063; 95%CI 0.011 to 0.116) and number of long bouts (0.108; 0.047 to 0.171) with depressive symptoms among men. MVPA moderated the associations of breaks and longer bouts of ST with depressive symptoms, with an increase of one break/hour, the increase of one long bout, and a decrease of 1 minute in mean bout length being associated with a reduction of 0.211 and increases of 0.081 and 0.166, respectively, in the number of depressive symptoms among men with physical inactivity (breaks =-0.211;-0.360 to-0.063; mean bout length = 0.081; 0.003 to 0.158; number of long bouts = 0.166; 0.090 to 0.242). CONCLUSIONS: Interventions that encourage breaking up ST should be helpful to reduce depressive symptoms among people with physical inactivity. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT03986879)

Micromechanical finite element analyses of fire retardant woven fabric composites at elevated temperatures using unit cells at multiple length scales

This paper presents a micromechanical Finite Element (FE) model developed to predict the effective mechanical properties of glass fibre-reinforced (woven fabric) polymer composites with/without fire retardant particulate additives at elevated temperatures. The elevated mechanical properties of glass fibre-reinforced epoxy composites with/without fire retardants were predicted using three unit cells of varying length scales in micromechanical FE analysis. Theoretically predictions of flexural behaviour of these fibre-reinforced polymer composites at elevated temperatures were satisfactorily validated against experimentally measured data. The numerical model developed herein was then used for the prediction of other mechanical properties of fibre-reinforced polymer composites that would have been difficult to collect at elevated temperatures. Micromechanical FE models such as the one contained in this paper are useful to architectural engineers as they can be used to guide the design and qualification of new engineering composites that satisfy stringent Building codes in fire prone engineering applications

Impact on adolescent mental health of replacing screen-use with exercise: A prospective cohort study

BACKGROUND: Screen-based device use could increase the risk of adolescent depression. Distinct modalities of screen-use may have differential effects on mental health. We used compositional data analysis to examine how theoretically replacing different screen-uses with exercise might influence future adolescent emotional distress. METHODS: In 4,599 adolescents (55% female) from a nationally-representative, prospective cohort, we used time-use diary data at age 14 to estimate daily screen use (television, social media, video game, general computer use) and exercise (team sport and individual exercise). The outcome was emotional distress at age 17, assessed using the emotional symptoms subscale of the Strengths and Difficulties Questionnaire. RESULTS: Theoretically replacing 60 minutes of total screen time with exercise at age 14 was associated with a 0.05 (95%CI -0.08, -0.02) score reduction on the emotional symptoms' subscale at 17 in fully-adjusted models. Replacing 60 minutes of television or social media use with team sports was associated with a reduction of 0.17 (95%CI, -0.31, -0.04) and 0.15 (95%CI, -0.29, -0.01) in emotional symptom scores, respectively. We found no change in emotional symptom scores when replacing video game or general computer use with team sport, or when replacing any screen time with individual exercise. LIMITATIONS: No direct measure of depressive symptoms at follow-up. CONCLUSIONS: Replacing any screen time with exercise could reduce emotional distress, but the largest effect sizes were associated with replacing time in television watching and social media with team sports. Recommendations to limit screen-use in adolescents may require a nuanced approach for protecting mental health

Prospective Associations of Leisure-Time Physical Activity With Psychological Distress and Well-Being: A 12-Year Cohort Study

OBJECTIVE: To investigate the associations of leisure-time physical activity with psychological distress and wellbeing, and potential mediators. METHODS: We used data from the 1970 British Cohort Study (N = 5,197 - 2,688 men), including waves 34y (2004), 42y (2012), and 46y (2016) waves. Participants reported leisure-time physical activity frequency and intensity (exposure) at age 34 (baseline), cognition (vocabulary test), body mass index, disability, mobility and pain perception (potential mediators) at age 42, and psychological distress (Malaise inventory) and wellbeing (Warwick-Edinburgh scale) at age 46. Baseline confounders included sex, country, education, employment status, alcohol use, tobacco smoking, and psychological distress. Main analyses included logistic regression and mediation models. RESULTS: Higher leisure-time physical activity intensity at baseline was associated with lower psychological distress at 46y [β: -0.038 (95%CI: -0.069 to -0.007)], but not leisure-time physical activity frequency. Baseline leisure-time physical activity frequency and intensity were associated with higher psychological well-being at 46y [frequency: β: 0.089 (95%CI: 0.002 to 0.176); intensity: β: 0.262 (95%CI: 0.123 to 0.401); and total: β: 0.041 (95%CI: 0.013 to 0.069)]. Only body mass index at 42y partially mediated the association between leisure-time physical activity frequency (15.7%) and total leisure-time physical activity (6.2%) at 34y, with psychological wellbeing at 46y. CONCLUSIONS: These findings highlight the role of leisure-time physical activity in psychological distress and wellbeing, with greater effect sizes associated with higher frequency and intensity of leisure-time physical activity. Future interventions should consider examining potential mediators of the association of leisure-time physical activity with psychological wellbeing, such as body mass index

Cotton in the new millennium: advances, economics, perceptions and problems

Cotton is the most significant natural fibre and has been a preferred choice of the textile industry and consumers since the industrial revolution began. The share of man-made fibres, both regenerated and synthetic fibres, has grown considerably in recent times but cotton production has also been on the rise and accounts for about half of the fibres used for apparel and textile goods. To cotton’s advantage, the premium attached to the presence of cotton fibre and the general positive consumer perception is well established, however, compared to commodity man-made fibres and high performance fibres, cotton has limitations in terms of its mechanical properties but can help to overcome moisture management issues that arise with performance apparel during active wear. This issue of Textile Progress aims to: i. Report on advances in cotton cultivation and processing as well as improvements to conventional cotton cultivation and ginning. The processing of cotton in the textile industry from fibre to finished fabric, cotton and its blends, and their applications in technical textiles are also covered. ii. Explore the economic impact of cotton in different parts of the world including an overview of global cotton trade. iii. Examine the environmental perception of cotton fibre and efforts in organic and genetically-modified (GM) cotton production. The topic of naturally-coloured cotton, post-consumer waste is covered and the environmental impacts of cotton cultivation and processing are discussed. Hazardous effects of cultivation, such as the extensive use of pesticides, insecticides and irrigation with fresh water, and consequences of the use of GM cotton and cotton fibres in general on the climate are summarised and the effects of cotton processing on workers are addressed. The potential hazards during cotton cultivation, processing and use are also included. iv. Examine how the properties of cotton textiles can be enhanced, for example, by improving wrinkle recovery and reducing the flammability of cotton fibre