Using Optical Tweezers Combined with Total Internal Reflection Microscopy to Study Interactions Between the ER and Golgi in Plant Cells.

Optical tweezers have been used to trap and micro-manipulate several biological specimens ranging from DNA, macromolecules, organelles, to single-celled organisms. Using a combination of the refraction and scattering of laser light from a focused laser beam, refractile objects are physically captured and can be moved within the surrounding media. The technique is routinely used to determine biophysical properties such as the forces exerted by motor proteins. Here, we describe how optical tweezers combined with total internal reflection fluorescence microscopy (TIRF) can be used to assess physical interactions between organelles, more specifically the ER and Golgi bodies in plant cells.

Evaluating a multi-behavioural home-based intervention for reducing depressive symptoms in postnatal women : The food, move, sleep (FOMOS) for postnatal mental health randomised controlled trial protocol.

BACKGROUND: Postnatal depression (PND) is a leading cause of illness and death among women following childbirth. Physical inactivity, sedentary behaviour, poor sleep, and sub-optimal diet quality are behavioural risk factors for PND. A feasible, sustainable, and scalable intervention to improve healthy behaviours and reduce PND symptoms among women at postpartum is needed. This study aims to examine the effectiveness of a multi-behavioural home-based program Food, Move, Sleep (FOMOS) for Postnatal Mental Health designed to improve PND symptoms in women at postpartum. METHODS: This randomised clinical trial will recruit 220 Australian women (2-12 months postpartum) experiencing heightened PND symptoms (Edinburgh Postnatal Depression Scale score ≥ 10). Participants will be randomised to FOMOS or wait-list control receiving standard clinical care. FOMOS is a 6-month mobile health (mHealth) intervention targeting diet quality, physical activity, sedentary behaviour, sleep, and mental health. The intervention, informed by the Social Cognitive Theory and incorporating behaviour change techniques defined in the CALO-RE taxonomy and Cognitive Behavioural Treatment of Insomnia, provides exercise equipment, and educational/motivational material and social support via mHealth and social media. Data collection pre-intervention and at 3, 6 and 12 months will assess the primary outcome of PND symptoms and secondary outcomes (diet quality, physical activity, sitting time, sleep quality) using self-report and device measures. Process evaluation will explore acceptability, appropriateness, cost-effectiveness, feasibility, and sustainability via analytic tools, record keeping, interviews, and surveys. DISCUSSION: If effective, FOMOS could be a feasible and potentially scalable management strategy to support improvement of health behaviours and mental health for women with PND symptoms. TRIAL REGISTRATION: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12622001079730p.

Associations of Recreational and Nonrecreational Physical Activity and Body Weight Change on Cardiovascular Disease Mortality During the Obesogenic Transition in the United States: National Health and Nutrition Examination Survey Follow-up Study.

BACKGROUND: To investigate cardiovascular disease mortality associated with longitudinal changes in body weight, and recreational and nonrecreational physical activity during the obesogenic transition in the United States since the 1970s. METHODS: Data were analyzed from 4921 individuals aged 25-74 years who participated in the National Health and Nutrition Examination Survey between 1971 and 1979 and follow-up studies to 1992. Mortality was confirmed by searching the National Death Index or proxy interview; clinical data were collected in person. Changes in self-reported recreational and nonrecreational physical activity categories over time were coded as stable, increase, or decrease. Competing risks regression was used to determine hazard ratios adjusted for covariates. A logit model in a generalization method was used to explore mediation effects of change in body weight. RESULTS: Compared with the "moderate-vigorous stable" group (reference), individuals who remained inactive ("inactive stable") or reduced their participation in physical activity ("active to inactive") experienced the highest mortality, with a 50% to 176% and 22% to 222% relative increased hazard ratios for nonrecreational and recreational physical activity, respectively, across all models adjusted for covariates. This corresponded to significant loss of life (up to 3 y; all P < .05). Individuals who became active ("inactive to active") were not at increased risk. We found weak (but nonstatistically significant) evidence of mediation effects of body weight change on mortality. CONCLUSIONS: Longitudinal changes in moderate-vigorous recreational and nonrecreational physical activity were important predictors of cardiovascular disease mortality during the obesogenic transition period in the United States and were mostly unexplained by changes in body weight.

Fertility preservation, its effectiveness and its impact on disease status in pre-menopausal women with breast cancer: A systematic review and meta-analysis.

INTRODUCTION: Preservation of reproductive function is a key concern for many premenopausal women with breast cancer, given the known gonadotoxic effects of treatments. The present systematic review aimed to investigate the effectiveness and safety of fertility preservation strategies in pre-menopausal women with breast cancer. METHODS: Primary research assessing fertility preservation strategies of any type was identified. Markers of preservation of fertility including return of menstrual function, clinical pregnancy rates and live birth rates were selected as main outcome measures. An additional analysis of safety data was also performed. RESULTS: Fertility preservation interventions were overall associated with higher fertility outcomes: with a pooled odds ratio 4.14 (95% CI 3.59-4.77) for any kind of fertility preservation intervention. This was seen both for return of menstruation and for clinical pregnancy rate, but not for live birth rates. Fertility preservation was associated with a reduced rate of disease recurrence (OR 0.63 (95% CI 0.49-0.81)), while there was no significant difference in disease free survival (OR 0.88 (95% CI 0.74-1.05)) or in overall survival (OR 0.9 (95% CI 0.74-1.10)) between the fertility preservation group and those who had not undergone fertility preservation. CONCLUSION: Fertility preservation is both effective in preserving reproductive function, and safe with regard to disease recurrence, disease free survival and overall survival in premenopausal women with breast cancer.

Optimising the effects of physical activity on mental health and wellbeing: A joint consensus statement from Sports Medicine Australia and the Australian Psychological Society.

OBJECTIVES: This consensus statement from Sports Medicine Australia and the Australian Psychological Society aims to provide guidance to practitioners on the ways that physical activity can be promoted to maximise benefits to mental health. METHODS: Following the Clinical Consensus Statement protocol, an expert group comprised of eight members with expertise in physical activity and mental health articulated recommendations regarding five physical activity contextual factors: type, physical environment, delivery, domain, and social environment. RESULTS: To optimise the mental health benefits of physical activity, we recommend: i) activity selection be guided by factors associated with adherence and enjoyment as opposed to any specific type (type); ii) facilitators (i.e., teachers, coaches, instructors, practitioners) deliver organised physical activity sessions using an instructional style that satisfies individuals' basic needs for autonomy, competence and social connection (delivery); iii) participation in physical activity with others who provide support, facilitate positive interactions, or make people feel valued, so long as it does not undermine a preference to be active alone (social environment); iv) where possible and appropriate, some physical activity should be undertaken outside in pleasant natural environments (physical environment); and, v) at least some physical activity be undertaken during leisure-time or via active travel, where possible prioritising activities one personally chooses to undertake (domain). CONCLUSIONS: The type, domain, physical and social environment of physical activity, as well as the way in which it is delivered, will determine mental health outcomes. Practitioners can use these recommendations to optimise the effects of physical activity on mental health.

Does physical activity mediate the associations between blue space and mental health? A cross-sectional study in Australia.

BACKGROUND: Research has begun to examine whether blue space is beneficial to mental health. While results are promising, it is difficult to know which aspects of mental health or mental ill-health may benefit most. Physical activity has been proposed as one potential mechanism via which blue space may be associated with better mental health. However, very few studies have examined mechanisms. We examined associations between blue space proximity and a range of mental health outcomes and examined which of these associations were mediated by physical activity. METHODS: 350 participants (M = 38.74, SD = 14.92, 70% female) self-reported their weekly physical activity and completed measures of depression, anxiety, and psychological wellbeing. We then used GIS software to calculate blue space proximity (i.e., coastal and inland), and structural equation modelling with mediation paths to determine the role of physical activity in the associations between bluespace and mental health. RESULTS: Physical activity partially mediated the associations between coastal proximity and depression (ß = 0.02, 95% CI = 0.001, 0.05), anxiety (ß = 0.03, 95% CI = 0.01, 0.06), and wellbeing (ß = - 0.03, 95% CI = - 0.08, - 0.01), and fully mediated the associations between inland water proximity and depression (ß = 0.02, 95% CI = 0.003, 0.05), anxiety (ß = 0.03, 95% CI = 0.01, 0.07), and wellbeing (ß = - 0.03, 95% CI = - 0.07, - 0.01). CONCLUSION: While physical activity appears to explain associations between inland blue space and mental health outcomes, it only partially explains the association between coastal blue space and mental health, suggesting other mechanisms may play a role and even inactive exposure may be beneficial.

Self-Esteem, Meaningful Experiences and the Rocky Road-Contexts of Physical Activity That Impact Mental Health in Adolescents.

Abundant evidence shows that physical activity benefits adolescents' mental health and wellbeing. Quantitative evidence has shown that adolescents engaging in leisure time physical activity, a number of sports, and team sport, display better mental health outcomes than their peers. The specific contextual factors that contribute to increased mental health and wellbeing through physical activity are, as yet, unconfirmed. The purpose of this study was to identify the contexts of physical activity and sport that positively impact mental health and wellbeing as perceived by adolescents. A sample of 58 adolescents participated in 13 focus groups discussing various factors related to physical activity, sport and mental health. Participants brought an object that represented physical activity and an image that represented wellbeing to each focus group to aid in the discussion and representation of both. An inductive thematic analysis was conducted on transcripts of the focus groups using a six-phase approach. Five key themes were identified: (1) achievements and improvements leading to increased self-esteem; (2) the importance of meaningful experiences, a sense of belonging and contributions to identity; (3) development of resilience and responding to setbacks; (4) social connectedness and relatedness, and (5) an opportunity to experience mindfulness, distraction and flow-states. In order to enhance and support wellbeing through physical activity, adolescents should be encouraged and provided with opportunities to engage in enjoyable activities with people with whom they experience a sense of belonging, where there is an opportunity to experience mastery and improvement and that includes an element of autonomy or choice.

Barriers and enablers in the implementation and sustainability of toothbrushing programs in early childhood settings and primary schools: a systematic review.

BACKGROUND: Untreated dental caries negatively impacts a child's quality of life including overall health and wellbeing, growth and development, social interaction ability, and school attendance. School-based toothbrushing programs have been recognised as an effective intervention to reduce the burden of dental caries. However, limited information is available to understand the real-world enablers and challenges in the implementation and sustainability of toothbrushing programs. This review aims to understand the barriers and enablers in the implementation and sustainability of toothbrushing programs in early childhood settings and primary schools. METHODS: Five electronic databases [i.e., CINAHL (EBSCO), Medline (EBSCO), EMBASE (Ovid), Web of Science, and PsycINFO] and backward citation chasing were performed. The last updated databases searches were conducted in May 2022. Studies reporting on barriers and enablers in the implementation and sustainability of toothbrushing programs in early childhood settings or primary schools were included in the review. The methodological quality of included studies was assessed by using Joanna Briggs Institute [JBI] and mixed methods appraisal tool [MMAT] critical appraisal tools and results were reported in accordance with PRISMA guidelines. RESULTS: A total of six studies met the eligibility criteria and were included in the review. Toothbrushing programs in early childhood settings and primary schools were mostly implemented under the supervision of staff and teachers. A positive attitude of the staff, the flexibility of toothbrushing sessions, involvement of community volunteers and parents were a few of the identified enablers. However, the timing of the communication of the program, inadequate transfer of information among staff, frequent staffing turnover, lack of parental support, and staff feeling overburdened while acting as pseudo parents were frequently reported as barriers. CONCLUSION: The results of this systematic review identify key enablers and barriers for toothbrushing programs in early childhood settings and primary schools which need to be considered for developing oral health promotion initiatives.

Sex differences and sex bias in human circadian and sleep physiology research.

Growing evidence shows that sex differences impact many facets of human biology. Here we review and discuss the impact of sex on human circadian and sleep physiology, and we uncover a data gap in the field investigating the non-visual effects of light in humans. A virtual workshop on the biomedical implications of sex differences in sleep and circadian physiology led to the following imperatives for future research: i) design research to be inclusive and accessible; ii) implement recruitment strategies that lead to a sex-balanced sample; iii) use data visualization to grasp the effect of sex; iv) implement statistical analyses that include sex as a factor and/or perform group analyses by sex, where possible; v) make participant-level data open and available to facilitate future meta-analytic efforts.

Shared Medical Appointments and Mindfulness for Type 2 Diabetes-A Mixed-Methods Feasibility Study.

Introduction: Type 2 diabetes (T2DM) is a major health concern with significant personal and healthcare system costs. There is growing interest in using shared medical appointments (SMAs) for management of T2DM. We hypothesize that adding mindfulness to SMAs may be beneficial. This study aimed to assess the feasibility and acceptability of SMAs with mindfulness for T2DM within primary care in Australia. Materials and Methods: We conducted a single-blind randomized controlled feasibility study of SMAs within primary care for people with T2DM living in Western Sydney, Australia. People with T2DM, age 21 years and over, with HbA1c > 6.5% or fasting glucose >7.00 mmol/L within the past 3 months were eligible to enroll. The intervention group attended six 2-h programmed SMAs (pSMAs) which were held fortnightly. pSMAs included a structured education program and mindfulness component. The control group received usual care from their healthcare providers. We collected quantitative and qualitative data on acceptability as well as glycemic control (glycated hemoglobin and continuous glucose monitoring), lipids, anthropometric measures, blood pressure, self-reported psychological outcomes, quality of life, diet, and physical activity using an ActiGraph accelerometer. Results: Over a 2-month period, we enrolled 18 participants (10 females, 8 males) with a mean age of 58 years (standard deviation 9.8). We had 94.4% retention. All participants in the intervention group completed at least four pSMAs. Participants reported that attending pSMAs had been a positive experience that allowed them to accept their diagnosis and empowered them to make changes, which led to beneficial effects including weight loss and better glycemic control. Four pSMA participants found the mindfulness component helpful while two did not. All of the seven participants who contributed to qualitative evaluation reported improved psychosocial wellbeing and found the group setting beneficial. There was a significant difference in total cholesterol levels at 12 weeks between groups (3.86 mmol/L in intervention group vs. 4.15 mmol/L in the control group; p = 0.025) as well as pain intensity levels as measured by the PROMIS-29 (2.11 vs. 2.38; p = 0.034). Conclusion: pSMAs are feasible and acceptable to people with T2DM and may result in clinical improvement. A follow-up fully-powered randomized controlled trial is warranted. Clinical Trial Registration: Australia and New Zealand Clinical Trial Registry, identifier ACTRN12619000892112.

Adherence to aerobic and muscle-strengthening exercise guidelines and associations with psychological distress: A cross-sectional study of 14,050 English adults.

Physical activity (PA) is beneficial for the prevention and management of psychological distress. However, no studies have investigated which combination/s of PA prescribed in the current global guidelines (i.e. aerobic moderate-to-vigorous PA [MVPA] and muscle-strengthening exercise [MSE]) are most strongly linked to reduced psychological distress. This study aimed to examine how PA guidelines adherence is associated with psychological distress. Using cross-sectional data of adults (n = 14,050) who participated in the 2012-2016 Health Survey for England, four categories of self-reported PA guidelines adherence were created: meeting none, only MSE, only aerobic MVPA, meeting both (exposure variables). Psychological distress (outcome) was measured using the General Health Questionnaire-12. The likelihood of experiencing high levels of psychological distress (cut-point of ≥4) across guidelines adherence categories was examined using logistic regression models adjusted for sociodemographic and lifestyle factors. About 17% of adults experienced high levels of psychological distress; 37.5% did not adhere to any PA guidelines (category 1), 1.3% met only MSE (category 2), 35.5% met only aerobic MVPA (category 3), and 25.7% met both guidelines (category 4). Compared to category 1, the likelihood of experiencing high psychological distress was lowest in category 4 (OR = 0.65, 95% CI: 0.54-0.77) followed by category 3 (OR = 0.78, 95% CI: 0.67-0.90), while it did not differ in category 2 (OR = 1.24, 95% CI: 0.75-2.05). This is the first study to identify the association between PA guidelines adherence and psychological distress in a large population sample. Findings suggest that meeting both aerobic MVPA and MSE guidelines might be most beneficial for mental health.

Work-related physical activity and psychological distress among women in different occupations: a cross-sectional study.

BACKGROUND: Recent evidence suggests that work-related physical activity may not have the same mental health benefits as leisure-time physical activity. Further, work-related physical activity is likely to include a variety of different behaviours for people with different occupations. As such, the aim of this study was to determine if occupation type moderated the association between work-related physical activity and psychological distress. METHODS: A randomly selected sample of 1080 women from Melbourne, Australia completed the International Physical Activity Questionnaire (IPAQ) and General Health Questionnaire (GHQ-30), and reported their current occupation. RESULTS: Linear regression analyses indicated that occupation significantly moderated the association between work-related walking and psychological distress (F [8, 55] = 2.26, p = .036). Given evidence of moderation, we fitted linear regression models to test the associations between work-related physical activity and psychological distress for three separate groups; professionals, sales and services workers, and tradespersons. Female tradespersons who engaged in a low (B = - 3.81, p = .006) or high amount of work-related walking (B = - 3.23, p = .029), had significantly lower psychological distress symptoms than those who engaged in no work-related walking. There were no significant associations between work-related physical activity of any intensity and psychological distress for professionals, or sales and service workers. CONCLUSIONS: Given the relationship does not exist across all occupations, work-related physical activity should not be promoted above and beyond leisure-time physical activity. However, walking at work may be important in reducing psychological distress for some people and should therefore, not be discounted.

Miro2 tethers the ER to mitochondria to promote mitochondrial fusion in tobacco leaf epidermal cells.

Mitochondria are highly pleomorphic, undergoing rounds of fission and fusion. Mitochondria are essential for energy conversion, with fusion favouring higher energy demand. Unlike fission, the molecular components involved in mitochondrial fusion in plants are unknown. Here, we show a role for the GTPase Miro2 in mitochondria interaction with the ER and its impacts on mitochondria fusion and motility. Mutations in AtMiro2's GTPase domain indicate that the active variant results in larger, fewer mitochondria which are attached more readily to the ER when compared with the inactive variant. These results are contrary to those in metazoans where Miro predominantly controls mitochondrial motility, with additional GTPases affecting fusion. Synthetically controlling mitochondrial fusion rates could fundamentally change plant physiology by altering the energy status of the cell. Furthermore, altering tethering to the ER could have profound effects on subcellular communication through altering the exchange required for pathogen defence.

Moderate-to-vigorous physical activity as a predictor of changes in physical self-concept in adolescents.

OBJECTIVE: Physical self-concept and moderate-to-vigorous physical activity (MVPA) are fundamental components of adolescents' health and well-being. Previous research suggests that physical self-concept and MVPA share reciprocal relations whereby physical self-concept is both an antecedent (i.e., self-enhancement) and outcome (i.e., skill development) of MVPA. However, these studies rely on subjective reports of MVPA, which can produce social desirability bias and challenge youth's recall capabilities. In order to address this gap, we test a reciprocal effects model examining the interplay between adolescents' physical self-concept and its facets and 7 days of objectively measured MVPA. METHOD: Australian adolescents (N = 1,767) completed 4,136 time-specific observations across 3 waves of data. Structural equation modeling was used to test the reciprocal effects model. RESULTS: After controlling for body mass index and sex, results only supported the role of MVPA as an antecedent of physical self-concept. The percentage of time adolescents spent in MVPA during school was especially important to predicting a higher physical self-concept in the future. CONCLUSIONS: Findings did not support a reciprocal effects model of physical self-concept and objectively measured MVPA. Rather, physical self-concept and facets were outcomes of school-based MVPA, suggesting emphasis be placed on promoting adolescents' physical activity participation. This study demonstrates the benefits that school MVPA provides to adolescents' development of a positive physical self-concept, which is essential to optimizing long-term health and well-being. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

A monitoring system to provide feedback on student physical activity during physical education lessons.

School-based physical education (PE) provides opportunities to accumulate moderate-to-vigorous physical activity (MVPA), but many students are insufficiently active during PE lessons. Providing teachers with feedback regarding their students' physical activity may increase the effectiveness of PE for achieving MVPA goals, but existing physical activity monitoring technologies have limitations in class environments. Therefore, the purpose of this study was to develop and validate a system capable of providing feedback on PE lesson MVPA. Equations for translating step counts to %MVPA were derived from measures in 492 students who concurrently wore an ActiGraph GT3X+ (ActiGraph) and Yamax pedometer (Yamax) during a PE lesson. To enhance feedback availability during PE lessons, we then developed a bespoke monitoring system using wireless tri-axial pedometers (HMM) and a smart device app. After developing and testing the monitoring system, we assessed its validity and reliability in 100 students during a PE lesson. There was a strong correlation of 0.896 between step counts and accelerometer-determined %MVPA and quantile regression equations showed good validity for translating step counts to %MVPA with a mean absolute difference of 5.3 (95% CI, 4.4-6.2). The physical activity monitoring system was effective at providing %MVPA during PE lessons with a mean difference of 1.6 ± 7.1 compared with accelerometer-determined %MVPA (7% difference between the two measurement methods). Teachers and students can use a smart device app and wireless pedometers to conveniently obtain feedback during PE lessons. Future studies should determine whether such technologies help teachers to increase physical activity during PE lessons.

An internet-supported school physical activity intervention in low socioeconomic status communities: results from the Activity and Motivation in Physical Education (AMPED) cluster randomised controlled trial.

OBJECTIVE: Quality physical education (PE) is the cornerstone of comprehensive school physical activity (PA) promotion programmes. We tested the efficacy of a teacher professional learning intervention, delivered partially via the internet, designed to maximise opportunities for students to be active during PE lessons and enhance adolescents' motivation towards PE and PA. METHODS: A two-arm cluster randomised controlled trial with teachers and Grade 8 students from secondary schools in low socioeconomic areas of Western Sydney, Australia. The Activity and Motivation in Physical Education (AMPED) intervention for secondary school PE teachers included workshops, online learning, implementation tasks and mentoring sessions. The primary outcome was the proportion of PE lesson time that students spent in moderate-to-vigorous physical activity (MVPA), measured by accelerometers at baseline, postintervention (7-8 months after baseline) and maintenance (14-15 months). Secondary outcomes included observed PE teachers' behaviour during lessons, students' leisure-time PA and students' motivation. RESULTS: Students (n=1421) from 14 schools completed baseline assessments and were included in linear mixed model analyses. The intervention had positive effects on students' MVPA during lessons. At postintervention, the adjusted mean difference in the proportion of lesson time spent in MVPA was 5.58% (p<0.001, approximately 4 min/lesson). During the maintenance phase, this effect was 2.64% (p<0.001, approximately 2 min/lesson). The intervention had positive effects on teachers' behaviour, but did not impact students' motivation. CONCLUSIONS: AMPED produced modest improvements in MVPA and compares favourably with previous interventions delivered exclusively face-to-face. Online teacher training could help facilitate widespread dissemination of professional learning interventions. TRIAL REGISTRATION NUMBER: ACTRN12614000184673.

Domain-specific physical activity and affective wellbeing among adolescents: an observational study of the moderating roles of autonomous and controlled motivation.

BACKGROUND: Abundant evidence demonstrates a relationship between physical activity and mental wellbeing. However, the strength of the relationship is not consistent. Factors contributing to variation in the strength of association are not well understood and, therefore, it remains difficult to optimize physical activity to ensure the strongest possible relationship with mental health. Self-determination theory suggests that more autonomously motivated behaviors lead to better mental health outcomes, when compared to more controlled behaviors. Therefore, we examined whether autonomous and controlled motivation moderated the relationships between physical activity and affective wellbeing within two domains (i.e., leisure-time and active travel). METHODS: Between February and April 2014, adolescents (N = 1632, M age = 12.94 years, SD = 0.54, 55% male) wore an accelerometer across seven-days and completed self-report measures of leisure-time physical activity and active travel. They also completed two measures of motivation (towards leisure-time physical activity and active travel) and an affective wellbeing measure. RESULTS: Structural equation modeling revealed that greater self-reported leisure-time physical activity was associated with greater positive affect (ß = .29) and less negative affect (ß = -.19) and that motivation did not moderate these relationships. Self-reported active travel had no linear relationship with affective wellbeing, and motivation did not moderate these relationships. Accelerometer-measured leisure-time physical activity had no relationship with positive affect but, had a weak inverse association with negative affect (ß = -.09), and neither relationship was moderated by motivation. Accelerometer-measured active travel had no association with positive affect; however, autonomous motivation significantly moderated this association such that active travel had a positive association with positive affect when autonomous motivation was high (ß = .09), but a negative association when autonomous motivation was low (ß = -.07). Accelerometer-measured active travel had no association with negative affect. Despite some significant moderation effects, motivation did not consistently moderate the relationship between all physical activity variables (leisure-time and active travel, and self-report and accelerometer) and affective outcomes. CONCLUSIONS: Tailoring physical activity interventions and guidelines to prioritize leisure-time ahead of other life domains could benefit wellbeing. Promoting autonomous participation in active travel may also be associated with increased wellbeing among adolescents.

School Physical Activity Intervention Effect on Adolescents' Performance in Mathematics.

PURPOSE: The primary aim of this study was to test the effect of a school-based physical activity intervention on adolescents' performance in mathematics. A secondary aim was to explore potential mechanisms that might explain the intervention effect. METHODS: The Activity and Motivation in Physical EDucation intervention was evaluated using a two-arm cluster randomized controlled trial in 14 secondary schools located in low socioeconomic areas of Western Sydney, Australia. Study participants (n = 1173) were grade 8 students (mean age = 12.94 yr, SD = 0.54). The multicomponent intervention was designed to help teachers maximize students' opportunities for moderate-to-vigorous physical activity (MVPA) during physical education (PE) and enhance students' motivation toward PE. Mathematics performance was assessed as part of national testing in grade 7, which was the year before the trial began and then again in grade 9. Potential mediators were: (i) proportion of PE lesson time that students spent in MVPA and leisure time MVPA (%), measured using Actigraph GT3X+ accelerometers, and (ii) students' self-reported engagement (behavioral, emotional, and cognitive) during mathematics lessons. Mediators were assessed at baseline (grade 8) and follow-up (grade 9, 14-15 months after baseline). RESULTS: The effect of the intervention on mathematics performance was small-to-medium (ß = 0.16, P < 0.001). An intervention effect was observed for MVPA% in PE (ß = 0.59, P < 0.001), but not for leisure time MVPA or any of the engagement mediators. There were no significant associations between changes in potential mediators and mathematics performance. CONCLUSIONS: The Activity and Motivation in Physical EDucation intervention had a significant positive effect on mathematics performance in adolescents. However, findings should be interpreted with caution as the effect was small and not associated with changes in hypothesized mediators.

Using Optical Tweezers Combined with Total Internal Reflection Microscopy to Study Interactions Between the ER and Golgi in Plant Cells.

Optical tweezers have been used to trap and micromanipulate several biological specimens ranging from DNA, macromolecules, organelles to single celled organisms. Using a combination of the refraction and scattering of laser light from a focused laser beam, refractile objects are physically captured and can be moved within the surrounding media. The technique is routinely used to determine biophysical properties such as the forces exerted by motor proteins. Here, we describe how optical tweezers combined with total internal reflection fluorescence (TIRF) microscopy can be used to assess physical interactions between organelles, more specifically the ER and Golgi bodies in plant cells.

Modeling Endoplasmic Reticulum Network Maintenance in a Plant Cell.

The endoplasmic reticulum (ER) in plant cells forms a highly dynamic network of complex geometry. ER network morphology and dynamics are influenced by a number of biophysical processes, including filament/tubule tension, viscous forces, Brownian diffusion, and interactions with many other organelles and cytoskeletal elements. Previous studies have indicated that ER networks can be thought of as constrained minimal-length networks acted on by a variety of forces that perturb and/or remodel the network. Here, we study two specific biophysical processes involved in remodeling. One is the dynamic relaxation process involving a combination of tubule tension and viscous forces. The other is the rapid creation of cross-connection tubules by direct or indirect interactions with cytoskeletal elements. These processes are able to remodel the ER network: the first reduces network length and complexity whereas the second increases both. Using live cell imaging of ER network dynamics in tobacco leaf epidermal cells, we examine these processes on ER network dynamics. Away from regions of cytoplasmic streaming, we suggest that the dynamic network structure is a balance between the two processes, and we build an integrative model of the two processes for network remodeling. This model produces quantitatively similar ER networks to those observed in experiments. We use the model to explore the effect of parameter variation on statistical properties of the ER network.