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Background Studies have suggested that sitting time at work may lead to underperformance but they may underestimate the benefits to desk workers' performance of reducing occupational sitting time without considering the relative effects of the specific activities replaced. Aims To estimate differences in work performance (presenteeism, absenteeism and engagement) when occupational sitting time is reallocated to standing/stepping in desk workers. Methods Data for middle-aged desk workers were from a Japan-wide online survey (n  = 2228). Self-report proportion of occupational sitting and standing/stepping, work hours and work performance indicators, including absolute (ratings relating only to self) and relative (ratings of self, compared to others) presenteeism and absenteeism, and dimensions of work engagement, were collected. Partition and isotemporal substitution models were used to investigate the associations of occupational sitting and standing/stepping time with work performance, including their reallocation effects. Results In partition models, longer occupational sitting time was associated with a lower absolute presenteeism score (i.e. less productivity), lower absolute absenteeism (i.e. longer-than-expected work hours), and lower engagement. Longer occupational standing/stepping time was associated with lower absolute absenteeism and more engagement. Isotemporal substitution models showed that each hour of occupational sitting reallocated to standing/stepping was favourably associated with overall work engagement (B  = 0.087; 95% confidence interval 0.051, 0.122) and its dimensions (B ranged from 0.078 to 0.092), but was not associated with presenteeism or absenteeism. Conclusions These findings suggest that management support and practical initiatives to encourage desk workers to replace portions of their sitting time with standing/stepping may contribute to enhanced work engagement. [ABSTRACT FROM AUTHOR]

Background: Frequent use of screen-based devices could be a modifiable risk factor for adolescent depression, but findings have been inconsistent and mostly from cross-sectional studies. We examined prospective associations of video gaming, social media, and internet use with depressive symptoms in adolescents. Methods: A total of 11 341 adolescents from the Millennium Cohort Study, a representative, UK population-based. The main outcome was depressive symptoms from a Moods and Feelings Questionnaire (age 14). Exposures were frequency of video game, social media, and internet use (age 11). Physical activity (effect modifier) was measured by self-report. Results: The fully adjusted models indicated that boys playing video games most days, at least once a week, and at least once a month at age 11 had lower depression scores at age 14 by 24.2% (IRR = 0.77, 95% CI 0.66–0.91), 25.1% (IRR = 0.75, 95% CI 0.62–0.90), and 31.2% (IRR = 0.69, 95% CI 0.57–0.83), compared with playing less than once a month/never. In girls, compared with less than once a month/never, using social media most days at age 11 was associated with 13% higher depression scores at age 14 (IRR = 1.13, 95% CI 1.05–1.22). We found some evidence of associations between using the internet most days and depressive symptoms compared with less than once a month/never in boys (IRR = 0.86, 95% CI 0.75–1.00). More frequent video game use was consistently associated with fewer depressive symptoms in boys with low physical activity, but not in those with high physical activity. Conclusions: Different types of screen-time may have contrasting associations with depressive symptoms during adolescence. Initiatives to address adolescents' screen-time may require targeted approaches. [ABSTRACT FROM AUTHOR]

The Bayes factor is the gold-standard figure of merit for comparing fits of models to data, for hypothesis selection and parameter estimation. However, it is little-used because it has been considered to be subjective, and to be computationally very intensive. A simple computational method has been known for at least 30 years, but has been dismissed as an approximation. We show here that all three criticisms are misplaced. The method should be used to complement and augment all least-squares fitting, because it can give very different, and better outcomes than classical methods. It can discriminate between models with equal numbers of parameters and equally good fits to data. It quantifies the Occam's Razor injunction against over-fitting, and it demands that physically-meaningful parameters rejected by classical significance testing be included in the fitting, to avoid spurious precision and incorrect values for the other parameters. It strongly discourages the use of physically-meaningless parameters, thereby satisfying the Occam's Razor injunction to use existing entities for explanation rather than multiplying new ones. More generally, as a relative probability, the Bayes factor combines naturally with other quantitative information to guide action in the absence of certain knowledge. [ABSTRACT FROM AUTHOR]

This paper reviews the mechanical properties of graphene with particular attention to what is established and what is still uncertain. It clarifies the thickness and the elastic constants, and by also considering also phonon frequencies, it argues that "best values" come from graphite, when available. Properties not available from graphite include bending stiffness; this can be determined from studies of carbon nanotubes as well as graphene. In many ways, nanotubes provide access to fundamental properties of graphene, not least because they are the only form of graphene that can be unsupported (unstrained) in vacuum. Environmental effects are considered, including both interactions with substrates and with other solid and liquid media, which may affect the geometrical parameters defining graphene and associated elastic constants. Major uncertainties persist whether slipping or sticking dominates experimental observation, both between graphene and solid media, and between the layers of bilayer and multilayer graphene. The paper concludes with a short discussion of continuum and atomistic models of graphene. [ABSTRACT FROM AUTHOR]

The efficacy of strained layer threading dislocation filter structures in single crystal epitaxial layers is evaluated using numerical modeling for (001) face-centred cubic materials, such as GaAs or Si1-xGex, and (0001) hexagonal materials such as GaN. We find that threading dislocation densities decay exponentially as a function of the strain relieved, irrespective of the fraction of threading dislocations that are mobile. Reactions between threading dislocations tend to produce a population that is a balanced mixture of mobile and sessile in (001) cubic materials. In contrast, mobile threading dislocations tend to be lost very rapidly in (0001) GaN, often with little or no reduction in the immobile dislocation density. The capture radius for threading dislocation interactions is estimated to be approximately 40 nm using cross section transmission electron microscopy of dislocation filtering structures in GaAs monolithically grown on Si. We find that the minimum threading dislocation density that can be obtained in any given structure is likely to be limited by kinetic effects to approximately 104-105cm-2. [ABSTRACT FROM AUTHOR]

Paired associative stimulation (PAS) can induce plasticity in the motor cortex, as measured by changes in corticospinal excitability (CSE). This effect is attenuated in older and less active individuals. Although a single bout of exercise enhances PAS-induced plasticity in young, physically inactive adults, it is not yet known if physical activity interventions affect PAS-induced neuroplasticity in middle-aged inactive individuals. Sixteen inactive middle-aged office workers participated in a randomized cross-over design investigating how CSE and short-interval intracortical inhibition (SICI) were affected by PAS preceded by 3 h of sitting (SIT), 3 h of sitting interrupted every 30 min by 3 min of frequent short bouts of physical activity (FPA) and 2.5 h of sitting followed by 25 min of moderate-intensity exercise (EXE). Transcranial magnetic stimulation was applied over the primary motor cortex (M1) of the dominant abductor pollicis brevis to induce recruitment curves before and 5 min and 30 min post-PAS. Linear mixed models were used to compare changes in CSE using time and condition as fixed effects and subjects as random effects. There was a main effect of time on CSE and planned within-condition comparisons showed that CSE was significantly increased from baseline to 5 min and 30 min post-PAS, in the FPA condition, with no significant changes in the SIT or EXE conditions. SICI decreased from baseline to 5 min post-PAS, but this was not related to changes in CSE. Our findings suggest that in middle-aged inactive adults, FPAs may promote corticospinal neuroplasticity. Possible mechanisms are discussed. [ABSTRACT FROM AUTHOR]

The feasibility of a thin-wire torsion stress-strain experiment with nanostrain sensitivity is demonstrated. A gauge length of 50 m was made possible by using The Monument, London, thereby restoring it to its original purpose as a scientific instrument. A wire of 150 μm diameter was studied using the load-unload method, and data were recorded in the elastic regime and through the elastic-plastic transition. Analysis of this preliminary experiment suggested some necessary improvements to the equipment and methods. Progress towards definitive experiments is described together with difficulties still to be overcome. [ABSTRACT FROM AUTHOR]

The finite deformation theory of rubber and related materials is based on energy functions that describe the macroscopic response of these materials under deformation. Energy functions and elastic constants are here derived from a simple microscopic (ball-and-spring) model. Exact uniaxial force-extension relationships are given for Hooke’s Law and for the thermodynamic entropy-based microscopic model using the Gaussian and the inverse Langevin statistical approximations. Methods are given for finding the energy functions as expansions of tensor invariants of deformation, with exact solutions for functions that can be expressed as expansions in even powers of the extension. Comparison with experiment shows good agreement with the neo-Hookean energy function and we show how this derives directly from the simple Gaussian statistical model with a small modification. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulations of chloroform vapor and liquid at normal temperature and pressure and liquid under hydrostatic pressure are presented, giving bond lengths and vibrational frequencies as functions of pressure. The change in bond lengths between vapor and liquid at normal temperature and pressure is consistent with a pressure equivalent to the cohesive energy density (CED) of the liquid, supporting the solvation pressure model which predicts that solvated molecules or nanoparticles experience a pressure equal to the CED of the liquid. Experimental data for certain Raman frequencies of chloroform in the vapor phase, in the liquid, and in the liquid under pressure are presented and compared to MD. Results for C–Cl vibrational modes are in general agreement with the solvation pressure model whereas frequencies associated with the C–H bond are not. The results demonstrate that masking interactions exist in the real liquid that can be reduced or eliminated in simplified simulations. [ABSTRACT FROM AUTHOR]

The Lagrangian elastic constants cIJ and cIJK which are given in data-books are not stress-strain relationships. The relationships between them and any experimental observables are far from straightforward to evaluate under conditions of finite deformation when elasticity is nonlinear. We present effective second- and third-order elastic constants, which are thermodynamic stress-strain relationships and which express real material properties. They are derived by applying two and three independent strains to an elastic body and expressed in terms of the Lagrangian cIJ and cIJK. Experimental observables are readily calculated using the effective constants. Their application is demonstrated by deriving the Murnaghan equation of state, by calculating the stress-strain relationships of a pseudomorphic epitaxial strained layer, and by deriving the observable changes in acoustic velocities under stress. [ABSTRACT FROM AUTHOR]

Presents information on a study which measured the composition and strain of pseudomorphic epitaxial layers using high-resolution x-ray diffraction. Experimental details; Results and discussion; Conclusions.

Deals with a study which examined the relaxation behavior of undoped indium gallium phosphide layers grown by atomic layer molecular beam epitaxy. Technological application of the alloy; Methodology of the study; Results and discussion.

Presents information on a study which interpreted double-crystal x-ray rocking curves from metamorphic epitaxial heterostructures. Use of high-resolution x-ray diffraction; Experimental procedure; Conclusions.

Deals with a study which demonstrated that a simpler model with fewer input parameters can explain the role of implantation-created vacancies and account for their effect on the intermixing of a quantum well. Experimental method; Experimental results; Discussion and conclusion.

Presents information on a study that examined interdiffusion in InGaAs/GaAs quantum wells using photoluminescence to follow the development of the diffusion with time in a single sample. Experimental method; Results and discussion on the study; Conclusions.

Proposes a geometrical theory which predicts critical thickness and relaxation progress in strained epitaxial layers. Description of an idealized version of a model for predicting critical thickness and elaxation progress; Effect of various refinements on multilayered thin films; Details of experimental results which support the predictions of the model.

Presents a study which described a Green's function model of interface mixing in quantum wells that provides exact quantitative solutions for real structures. Examples of low-dimensional heterostructures; Calculation of composition profiles; Discussion on optical transitions in quantum wells.

The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk. [ABSTRACT FROM AUTHOR]

A high power pulsed laser system has been installed on the high magnetic field muon spectrometer (HiFi) at the International Science Information Service pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high magnetic field, which opens new applications of muon spin spectroscopy. In this report we give an overview of the principle of the HiFi laser system and describe the newly developed techniques and devices that enable precisely controlled photoexcitation of samples in the muon instrument. A demonstration experiment illustrates the potential of this unique combination of the photoexcited system and avoided level crossing technique. [ABSTRACT FROM AUTHOR]

Provides information on a study which investigated the dependence of the excitonic lifetime on the well width in InGaAs/InP (unstrained) InGaAs/GaAs, and InGaAsP/InP strained quantum well heterostructures by time-resolved photoluminescence spectroscopy. Contribution to the lifetime variation; Result that occurred from the onset of plastic relaxation; Factors performed mainly in lattice matched systems; Cause of the increase of the excitonic lifetime.

Background: Office workers engage in high levels of sitting time. Effective, context-specific, and scalable strategies are needed to support widespread sitting reduction. This study aimed to evaluate organisational-support strategies alone or in combination with an activity tracker to reduce sitting in office workers. Methods: From one organisation, 153 desk-based office workers were cluster-randomised (by team) to organisational support only (e.g., manager support, emails; 'Group ORG', 9 teams, 87 participants), or organisational support plus LUMOback activity tracker ('Group ORG + Tracker', 9 teams, 66 participants). The waist-worn tracker provided real-time feedback and prompts on sitting and posture. ActivPAL3 monitors were used to ascertain primary outcomes (sitting time during work- and overall hours) and other activity outcomes: prolonged sitting time (≥30 min bouts), time between sitting bouts, standing time, stepping time, and number of steps. Health and work outcomes were assessed by questionnaire. Changes within each group (three- and 12 months) and differences between groups were analysed by linear mixed models. Missing data were multiply imputed. Results: At baseline, participants (46 % women, 23-58 years) spent (mean ± SD) 74.3 ± 9.7 % of their workday sitting, 17.5 ± 8.3 % standing and 8.1 ± 2.7 % stepping. Significant (p < 0.05) reductions in sitting time (both work and overall) were observed within both groups, but only at 12 months. For secondary activity outcomes, Group ORG significantly improved in work prolonged sitting, time between sitting bouts and standing time, and overall prolonged sitting time (12 months), and in overall standing time (three- and 12 months); while Group ORG + Tracker, significantly improved in work prolonged sitting, standing, stepping and overall standing time (12 months). Adjusted for confounders, the only significant between-group differences were a greater stepping time and step count for Group ORG + Tracker relative to Group ORG (+20.6 min/16 h day, 95 % CI: 3.1, 38.1, p = 0.021; +846.5steps/16 h day, 95 % CI: 67.8, 1625.2, p = 0.033) at 12 months. Observed changes in health and work outcomes were small and not statistically significant. Conclusions: Organisational-support strategies with or without an activity tracker resulted in improvements in sitting, prolonged sitting and standing; adding a tracker enhanced stepping changes. Improvements were most evident at 12 months, suggesting the organisational-support strategies may have taken time to embed within the organisation. Trial registration: Australian New Zealand Clinical Trial Registry: ACTRN12614000252617. Registered 10 March 2014. [ABSTRACT FROM AUTHOR]

Strain-gradient plasticity theories have been developed to account for the size effect in small-scale plasticity in metals. However, they remain of limited use in engineering, for example in standards for nanoindentation, because of their phenomenological nature. In particular, a key parameter, the characteristic length, can only be determined by fitting to experiment. Here, it is shown that the characteristic length in one such theory derives directly from known quantities through fundamental dislocation physics. This explains and validates the theory for use in engineering. [ABSTRACT FROM PUBLISHER]

Summary: Objective: Investigate associations of TV viewing time and accelerometry‐derived sedentary time with inflammatory and endothelial function biomarkers in children. Methods: Cross‐sectional analysis of 164 7–10‐year‐old children. TV viewing time was assessed by parental proxy report and total and patterns of sedentary time accumulation (e.g. prolonged bouts) were assessed by accelerometry. C‐reactive protein (CRP), homeostasis model assessment of insulin resistance, interleukin‐2, ‐6, ‐8, ‐10, tumour necrosis factor alpha, adiponectin, resistin, brain‐derived neurotrophic factor, soluble intercellular and vascular adhesion molecule 1, plasminogen activator inhibitor 1 and soluble E‐selectin were assessed. Generalised linear models assessed the associations of TV viewing and sedentary time with biomarkers, adjusting for sex, waist circumference, moderate‐ to vigorous‐intensity physical activity and diet density. Results: Each additional h week−1 of TV viewing was associated with 4.4% (95% CI: 2.1, 6.7) greater CRP and 0.6% (0.2, 1.0) greater sVCAM‐1 in the fully adjusted model. The association between frequency and duration of 5–10 min bouts of sedentary time and CRP was positive after adjustment for sex and waist circumference but attenuated after adjustment for diet density. Conclusions: This study suggests that TV viewing was unfavourably associated with several markers of inflammation and endothelial dysfunction. The detrimental association between 5 and 10 min bouts of sedentary time and CRP approached significance, suggesting that further research with a stronger study design (longitudinal and/or experimental) is needed to better understand how the accumulation of sedentary time early in life may influence short and longer term health. [ABSTRACT FROM AUTHOR]

The experimental evidence for the Hall-Petch dependence of strength on the inverse square-root of grain size is reviewed critically. Both the classic data and more recent results are considered. While the data are traditionally fitted to the inverse squareroot dependence, they also fit well to many other functions, both power law and non-power law. There have been difficulties, recognized for half-a-century, in the inverse square-root expression. It is now explained as an artefact of faulty data analysis. A Bayesian meta-analysis shows that the data strongly support the simple inverse or lnd/d expressions. Since these expressions derive from underlying theory, they are also more readily explicable. It is concluded that the Hall-Petch effect is not to be explained by the variety of theories found in the literature, but is a manifestation of, or to be underlain by the general size effect observed throughout micromechanics, owing to the inverse relationship between the stress required and the space available for dislocation sources to operate. [ABSTRACT FROM AUTHOR]

Screen time, but not overall sedentary behaviour, is consistently related to cardiometabolic health in adolescents. Because of the associations screen time has with dietary intake, diet may be an important factor in the screen time and health relationship; however, evidence has not previously been synthesized. Thus, the aim of this systematic review was to explore whether the associations between various sedentary behaviours and cardiometabolic risk markers are independent of dietary intake in adolescents. Online databases and personal libraries were searched for peer-reviewed original research articles published in English before March 2014. Included studies assessed associations between sedentary behaviour and cardiometabolic markers in 12- to 18-year-olds and adjusted for dietary intake. Twenty-five studies met the inclusion criteria. From the 21 studies examining sedentary behaviour and adiposity, the majority found significant positive associations between television viewing, screen time and self-reported overall sedentary behaviour with markers of adiposity, independent of dietary intake. No significant associations between screen time with blood pressure and cholesterol were reported. Sedentary behaviour appears to be associated with adiposity in adolescents, irrespective of dietary intake. However, the variability of dietary variables between studies suggests further work is needed to understand the role of dietary intake when examining these associations in youth. [ABSTRACT FROM AUTHOR]

Excessive sedentary time is detrimentally linked to obesity, type 2 diabetes, cardiovascular disease and premature mortality. Studies have been investigating the use of activity-permissive workstations to reduce sedentary time in office workers, a highly sedentary target group. This review systematically summarizes the evidence for activity-permissive workstations on sedentary time, health-risk biomarkers, work performance and feasibility indicators in office workplaces. In July 2013, a literature search identified 38 relevant peer-reviewed publications. Key findings were independently extracted by two researchers. The average intervention effect on sedentary time was calculated via meta-analysis. In total, 984 participants across 19 field-based trials and 19 laboratory investigations were included, with sample sizes ranging from n = 2 to 66 per study. Sedentary time, health-risk biomarkers and work performance indicators were reported in 13, 23 and 23 studies, respectively. The pooled effect size from the meta-analysis was −77 min of sedentary time/8-h workday (95% confidence interval = −120, −35 min). Non-significant changes were reported for most health- and work-related outcomes. Studies with acceptability measures reported predominantly positive feedback. Findings suggest that activity-permissive workstations can be effective to reduce occupational sedentary time, without compromising work performance. Larger and longer-term randomized-controlled trials are needed to understand the sustainability of the sedentary time reductions and their longer-term impacts on health- and work-related outcomes. [ABSTRACT FROM AUTHOR]

Background: Bioelectrical impedance (BIA) represents a simple, inexpensive and non-invasive method that is often used to assess fat-mass (FM) and fat-free mass (FFM) in large population-based cohorts. Objective: The aim of this study was to describe the reference ranges and examine the influence of age and gender on FM, FFM and skeletal muscle mass (SMM) as well as height-adjusted estimates of FM [fat mass index (FMI)], FFM [fat-free mass index (FFMI)] and SMM [SMM index (SMI)] in a national, population-based cohort of Australian adults. Design and Participants: The analytical sample included a total of 8,582 adults aged 25-91 years of Europid origin with complete data involved in the cross-sectional 1999-2000 Australian, Diabetes, Obesity and Lifestyle (AusDiab) Study. Measurements: Bioelectrical impedance analysis was used to examine components of body composition. Demographic information was derived from a household interview. Results: For both genders, FFM, SMM and SMI decreased linearly from the age of 25 years, with the exception that in men SMI was not related to age and FFM peaked at age 38 years before declining thereafter. The relative loss from peak values to ≥75 years in FFM (6-8%) and SMM (11-15%) was similar between men and women. For FM and FMI, there was a curvilinear relationship with age in both genders, but peak values were detected 6-7 years later in women with a similar relative loss thereafter. For FFMI there was no change with age in men and a modest increase in women. Conclusion: In Australian adults there is heterogeneity in the age of onset, pattern and magnitude of changes in the different measures of muscle and fat mass derived from BIA, but overall the age-related losses were similar between men and women. [ABSTRACT FROM AUTHOR]

Background: Intensive lifestyle intervention trials in type 2 diabetes contribute evidence on what can be achieved under optimal conditions, but are less informative for translation in applied settings. Purpose: Living Well with Diabetes is a telephone-delivered weight loss intervention designed for real-world delivery. Methods: This study is a randomized controlled trial of telephone counseling ( n = 151) versus usual care ( n = 151); 6-month primary outcomes of weight, physical activity, HbA1c; secondary diet outcomes; analysis was by adjusted generalized linear models. Results: Relative to usual care, telephone counseling participants had small but significantly better weight loss [−1.12 % of initial body weight; 95 % confidence interval (CI) −1.92, −0.33 %]; physical activity [relative rate (RR) = 1.30; 95 % CI, 1.08, 1.57]; energy intake reduction (−0.63 MJ/day; 95 % CI, −1.01, −0.25); and diet quality (3.72 points; 95 % CI, 1.77, 5.68), with no intervention effect for HbA1c (RR = 0.99; 95 % CI, 0.96, 1.01). Conclusions: Results are discussed in light of challenges to intervention delivery. [ABSTRACT FROM AUTHOR]

Critical thickness theory for the plastic deformation of small stressed volumes is reviewed, with particular emphasis on its application to the size effect in common micromechanical testing methods, foil flexure, wire torsion, and compression and tension of micropillars and wires. Key predictions which distinguish the theory from others are that plasticity initiates throughout a finite volume when a strain-thickness product or strain-volume integral exceeds a critical value related to the Burgers vector; that misfit or geometrically necessary dislocations will generally be found outside this volume; and that the intrinsic or bulk strength of the material is not changed by the size effect. Experiments designed to test these predictions are briefly described. [ABSTRACT FROM AUTHOR]

Diabet. Med. 29, 593-599 (2012) Abstract Aims To investigate the joint influence of physical activity and family history of diabetes on the subsequent risk of developing hyperglycaemia and Type 2 diabetes among Chinese adults. Methods A prospective community-based cohort study was conducted among adults aged 35 years and older during 2004-2007 in Nanjing, China. Four communities (three urban and one rural) were randomly selected from 11 urban districts and two rural counties. Hyperglycaemia and Type 2 diabetes were defined using World Health Organization criteria based on fasting blood glucose concentration and physicians' diagnosis, respectively. Physical activity, parental diabetes history, and other important covariates were assessed at baseline and in the third-year follow-up survey. Results At study conclusion data were collected from 3031 participants (follow-up rate 81.3%). The 3-year cumulative incidence of hyperglycaemia and Type 2 diabetes was 6.2% and 2.4%, respectively. After adjustment for potential confounding variables, compared with those with positive family history and insufficient physical activity, the adjusted relative risk ratio (95% CI) of developing hyperglycaemia was 0.19 (0.02, 1.51) for participants with sufficient physical activity and a positive family history; 0.55 (0.31, 0.97) for participants with insufficient physical activity and a negative family history; and 0.36 (0.19, 0.70) for participants with sufficient physical activity but a negative family history. Participants who had a negative family history and insufficient physical activity were also less likely to develop Type 2 diabetes (RRR = 0.28; 0.14, 0.54), and participants with a negative family history and sufficient physical activity were the least likely to develop Type 2 diabetes (0.23; 0.10, 0.56). Conclusions Sufficient physical activity and negative family history of diabetes may jointly reduce the risk of developing hyperglycaemia and Type 2 diabetes in Chinese adults. [ABSTRACT FROM AUTHOR]

Objective:To assess the prospective relationship between obesity and health-related quality of life, including a novel assessment of the impact of health-related quality of life on weight gain.Design and setting:Longitudinal, national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study, with surveys conducted in 1999/2000 and 2004/2005.Participants:A total of 5985 men and women aged 25 years at study entry.Main outcome measure(s):At both time points, height, weight and waist circumference were measured and self-report data on health-related quality of life from the SF-36 questionnaire were obtained. Cross-sectional and bi-directional, prospective associations between obesity categories and health-related quality of life were assessed.Results:Higher body mass index (BMI) at baseline was associated with deterioration in health-related quality of life over 5 years for seven of the eight health-related quality of life domains in women (all P0.01, with the exception of mental health, P>0.05), and six out of eight in men (all P<0.05, with the exception of role-emotional, P=0.055, and mental health, P>0.05). Each of the quality-of-life domains related to mental health as well as the mental component summary were inversely associated with BMI change (all P<0.0001 for women and P0.01 for men), with the exception of vitality, which was significant in women only (P=0.008). For the physical domains, change in BMI was inversely associated with baseline general health in women only (P=0.023).Conclusions:Obesity was associated with a deterioration in health-related quality of life (including both physical and mental health domains) in this cohort of Australian adults followed over 5 years. Health-related quality of life was also a predictor of weight gain over 5 years, indicating a bi-directional association between obesity and health-related quality of life. The identification of those with poor health-related quality of life may be important in assessing the risk of future weight gain, and a focus on health-related quality of life may be beneficial in weight management strategies. [ABSTRACT FROM AUTHOR]

Simple test equipment has been developed for studying the elastic limit and plastic deformation of thin metal wires and thin foils (down to 10 μm) under torsion, tension, and bending. Using load-unload methods and gauge lengths up to 1 m, plastic strain as low as 10-6 can be measured accurately. [ABSTRACT FROM AUTHOR]

LYNCH B.M., DUNSTAN D.W., WINKLER E., HEALY G.N., EAKIN E. & OWEN N. (2010) European Journal of Cancer Care Physical activity is well-established on the cancer survivorship research agenda, but prostate cancer survivors remain an understudied population. Additionally, the unique relationships between sedentary time and health outcomes have not yet been considered in this group. We examined the associations of accelerometer-assessed physical activity and sedentary time with waist circumference in 103 prostate cancer survivors from the National Health and Nutrition Examination Survey 2003-2004 and 2005-2006. Participants wore an Actigraph accelerometer for 7 days, and activity levels were summarised as moderate-to-vigorous intensity activity (accelerometer counts/minute ≥1952), light-intensity activity (counts/minute 100-1951) and sedentary time (counts/minute < 100). Moderate-to-vigorous intensity physical activity was inversely associated with waist circumference ( β=−6.728, 95% CI: −12.267, −1.190, P= 0.020), equating to a top versus bottom quartile difference of 13.7 cm. No discernable relationship existed between light-intensity activity or sedentary time and adiposity. This is the first study to objectively measure the activity levels of prostate cancer survivors. Increasing moderate-to-vigorous activity may assist this population with weight management. More research into the relationships of light-intensity physical activity and sedentary behaviour with health outcomes among prostate cancer survivors is warranted, given the strong relationships seen in the broader population. [ABSTRACT FROM AUTHOR]

The size of microstructural features has long been known to determine the strength of materials, as in the Hall-Petch effect of grain size. More recently, the importance of the size of the structure itself (thin foil, wire or pillar) or of the loaded volume (indentation) has been recognised. Many phenomenological theories have been proposed to account for the size effect. Here, experimental data of very high accuracy are reported on copper wire in torsion which distinguish the size effects of grain size and structure size on the elastic limit and on the flow stress at low plastic strain. The data are compared with less accurate data from similar wires in tension. The size effects are shown to arise by first-principles analysis of dislocation behaviour, exploiting the slip-distance theory of Conrad together with forest (Taylor) work-hardening theory, but with modifications to both theories to account for finite structure size. The resulting theory is compatible with the concepts of dislocation starvation and of strain-gradient plasticity. The size effect in the elastic limit is due to the constraint the size puts on dislocation curvature, while the size effect on the flow stress is due to the constraint size puts on dislocation mean free path and to the fate of a dislocation after it has moved. [ABSTRACT FROM AUTHOR]

Polymer solutions are complex fluids that show elasticity and deformation in response to shear flows. A fluorescence resonance energy transfer (FRET) technique has been applied to measure the end-to-end distances of individual polymer molecules in Couette flow, using end-tagged reversible-addition fragmentation chain transfer (RAFT) polymerised poly(methyl methacrylate) (PMMA). Real-time rheofluorescence measurements on these polymers in solution above the critical overlap concentration are reported at several shear rates. The PMMA in Couette flow shows a systematic decrease in fluorescence, corresponding to a reduction in end-to-end distance of the polymer molecules with shear exposure. Full reversibility of the fluorescence signal is observed after the cessation of shear. These results show that polymer solution elasticity arises from compressive deformation of the polymer molecules in Couette flow. At polymer concentrations above the critical overlap, the polymer molecules are restricted by their neighbours and the net hydrodynamic forces are compressive rather than extensive. [ABSTRACT FROM AUTHOR]

We define a creep-flow-based measurement procedure to allow reliable and reproducible results on aging and yielding materials to be obtained. Investigation of the effects of different parameter such as the pre-shear time, the recovery time and the applied stress magnitude on the viscoelastic properties of a lyotropic liquid crystal phase is reported. Cryo-TEM observations indicate the formation of multiconnected bilayers at rest. Shearing the investigated material shows a propensity to acquire all the macroscopic properties of “soft jammed systems”. These properties are then interpreted in terms of shear-induced structural rearrangement on the basis of cryofracture observation obtained at different times after the preshear imposed. [ABSTRACT FROM AUTHOR]

Understanding the strengthening of small-scale materials and structures is one of the key issues in nanotechnology. Many theories exist, each addressing a small domain of experimentally observed size effects and invoking different mechanisms. Measurements of the stress-strain relationship of nickel foils in flexure by the load-unload method provide strikingly accurate data from the elastic region through the yield point and to high plastic strain. The data show that the effects on the rate of work-hardening due to crystallite size and sample size interact, whereas in existing theories they should be independent. Existing theories cannot be complete. The symmetry of the dependence of flow stress on grain size and structure size suggests that strengthening effects are due to a finite strained volume, however this is delimited. [ABSTRACT FROM AUTHOR]

Aim To determine the extent of gender-related differences in the prevalence of glucose intolerance for the Australian population and whether body size may explain such differences. Methods Cross-sectional data were collected from a national cohort of 11 247 Australians aged ≥ 25 years. Glucose tolerance status was assessed according to both fasting plasma glucose (FPG) and 2-h plasma glucose (2hPG) levels following a 75-g oral glucose tolerance test (OGTT). Anthropometric and glycated haemoglobin measurements were also made. Results Undiagnosed diabetes and non-diabetic glucose abnormalities were more prevalent among men than women when based only on the FPG results (diabetes: men 2.2%, women 1.6%, P = 0.02; impaired fasting glycaemia: men 12.3%, women 6.6%, P < 0.001). In contrast 16.0% of women and 13.0% of men had a 2hPG abnormality (either diabetes or impaired glucose tolerance, P = 0.14). Women had a mean FPG 0.3 mmol/l lower than men ( P < 0.001), but 2hPG 0.3 mmol/l higher ( P = 0.002) and FPG-2hPG increment 0.5 mmol/l greater ( P < 0.001). The gender difference in mean 2hPG and FPG-2hPG increment disappeared following adjustment for height. For both genders, those in the shortest height quartile had 2hPG levels 0.5 mmol/l higher than the tallest quartile, but height showed almost no relationship with the FPG. Conclusions Men and women had different glycaemic profiles; women had higher mean 2hPG levels, despite lower fasting levels. It appeared that the higher 2hPG levels for women related to lesser height and may be a consequence of using a fixed glucose load in the OGTT, irrespective of body size. [ABSTRACT FROM AUTHOR]

Background:Physical activity (PA) is inversely associated with obesity but the effect has been difficult to quantify using questionnaires. In particular, the shape of the association has not yet been well described. Pedometers provide an opportunity to better characterize the association.Methods:Residents of households over the age of 25 years in randomly selected census districts in Tasmania were eligible to participate in the AusDiab cross-sectional survey conducted in 1999–2000. 1848 completed the AusDiab survey and 1126 of these (609 women and 517 men) wore a pedometer for 2-weekdays. Questionnaire data on recent PA, TV time and other factors were obtained. The outcomes were waist circumference (in cm) and body mass index (BMI) (kg/m2).Results:Increasing daily steps were associated with a decline in the obesity measures. The logarithmic nature of the associations was indicated by a sharper decline for those with lower daily steps. For example, an additional 2000 steps for those taking only 2000 steps per day was associated with a reduction of 2.8 (95% confidence interval (CI): 2.1,4.4) cm in waist circumference among men (for women; 2.2 (95% CI: 0.6, 3.9 cm)) with a baseline of only 2000, steps compared to a 0.7 (95% CI 0.3, 1.1) cm reduction (for women; 0.6 (95% CI: 0.2, 1.0)) for those already walking 10 000 steps daily. In the multivariable analysis, clearer associations were detected for PA and these obesity measures using daily step number rather than PA time by questionnaire.Interpretation:Pedometer measures of activity indicate that the inverse association between recent PA and obesity is logarithmic in form with the greatest impact for a given arithmetic step number increase seen at lower levels of baseline activity. The findings from this study need to be examined in prospective settings.International Journal of Obesity (2007) 31, 797–804. doi:10.1038/sj.ijo.0803472; published online 17 October 2006 [ABSTRACT FROM AUTHOR]