Physical activity, screen time and dietary behaviours in New Zealand adolescents prior to and following the onset of the COVID-19 pandemic.

BACKGROUND: Insufficient physical activity, high screen time, and unhealthy dietary patterns among adolescents may have worsened during the pandemic, but data are lacking. This study compared physical activity, screen time and fruit and vegetable intake in adolescents from Dunedin, New Zealand, 5-6 years before (Study 1) and during (Study 2) the COVID-19 pandemic. METHODS: Adolescents completed an online survey as part of the Built Environment and Active Transport to School (BEATS) studies in 2014/2015 (Study 1; n = 1,266; age: 15.3 ± 1.4 years; 54.6% female) and 2021/2022 (Study 2; n = 819; age: 15.2 ± 1.4 years; 47.4% female). The proportion of adolescents meeting guidelines for physical activity (≥ 60 min/day of moderate-to-vigorous physical activity), outside school screen time (≤ 2 h/day) and fruit and vegetable intake (> 1 serving/day for both fruit and vegetables) was calculated. Data were analysed using multivariable linear and logistic regression modelling. RESULTS: Few adolescents met recommended health behaviour guidelines. Compared to Study 1, significantly greater proportions of adolescents at Study 2 met guidelines for physical activity (16.7% vs. 23.1%; p < 0.001) and outside school screen time (13.3% vs. 18.3%; p < 0.001) while fruit and vegetable intake was not different (29.6% vs. 27.0%; p = 0.322). Compared to Study 1, average outside school screen time at Study 2 was lower on both weekdays (5.0 ± 2.9 vs. 4.6 ± 2.9; p < 0.001) and weekend days (6.9 ± 3.5 vs. 6.1 ± 3.6 h/day; p < 0.001). Reported frequency of consuming sweets was higher and soft drinks lower at Study 2 versus Study 1. CONCLUSIONS: Despite observed higher levels of physical activity and lower levels of outside school screen time during the pandemic compared to the pre-pandemic levels, few adolescents met health behaviour guidelines at both time points. Therefore, comprehensive health promotion that aims to improve physical activity levels, screen time and dietary patterns for adolescents is still necessary to prevent chronic health conditions adulthood.

Early-stage dynamics of chloride ion-pumping rhodopsin revealed by a femtosecond X-ray laser.

Chloride ion-pumping rhodopsin (ClR) in some marine bacteria utilizes light energy to actively transport Cl- into cells. How the ClR initiates the transport is elusive. Here, we show the dynamics of ion transport observed with time-resolved serial femtosecond (fs) crystallography using the Linac Coherent Light Source. X-ray pulses captured structural changes in ClR upon flash illumination with a 550 nm fs-pumping laser. High-resolution structures for five time points (dark to 100 ps after flashing) reveal complex and coordinated dynamics comprising retinal isomerization, water molecule rearrangement, and conformational changes of various residues. Combining data from time-resolved spectroscopy experiments and molecular dynamics simulations, this study reveals that the chloride ion close to the Schiff base undergoes a dissociation-diffusion process upon light-triggered retinal isomerization.

Temporal relationships in the movement behaviour of adolescents: Testing and methodological considerations of the ActivityStat hypothesis.

The study aimed to investigate the ActivityStat hypothesis by examining the presence and the timeframe of the temporal relationships among physical activity (PA) levels and stationary time (ST) in adolescents. A secondary analysis was performed on data involving 356 adolescents in Dunedin, New Zealand. Participants wore a waist-worn accelerometer for several consecutive days to assess PA levels [i.e. light PA (LPA), and moderate-to-vigorous PA (MVPA)] and ST. Bayesian continuous-time structural equation modelling (CT-SEM) was used to examine the relationship between the behaviours over time and the timeframe during which these relationships occur. Increases in LPA, MVPA, and ST were positively associated with their later behaviours until 2.5, 1.7, and 2 days later, respectively. A cross-behavioural reciprocal and negative relationship between LPA and ST was demonstrated 0.4 days later. A positive relationship between ST and MVPA was observed until about 0.4 days later. This is the first study to investigate the ActivityStat hypothesis using Bayesian CT-SEM in adolescents, examining the multivariate relationships among different behaviours and the associated timeframes. To conclude, evidence of activity synergy was suggested for the within-behavioural relationships, while behavioural compensation was noted for ST. Thus, the findings provide some support for the ActivityStat hypothesis in adolescents.

Community Group-Based Physical Activity Programs for Immigrant Older Adults: A Systematic Realist Review.

Physical activity program interventions often lack sensitivity to the needs of older immigrant adults. The objective of this systematic realist review is to explain how, why, for whom, and under which circumstances community group-based physical activity programs work for immigrant older adults. The initial program theory was developed using prior research, team expertise, social cognitive theory, and knowledge user consultations. The program theory was tested and refined via a systematic review of the literature. Database searches were conducted in MEDLINE, EMBASE, CINAHL, Scopus, Cochrane Library, Sports Medicine and Education Index, and SPORTDiscus. A total of 22 sources of evidence met inclusion criteria and included intervention studies, systematic reviews, and a discussion paper. Intervention studies were appraised using the Mixed Methods Appraisal Tool. The final program theory constituted eight context-mechanism-outcome configurations that highlight the importance of facilitator characteristics, access to safe spaces, group dynamics, and social support. A limitation was the small number and variable quality of included evidence. Physical activity programs that target immigrant older adults must strengthen physical and psychological safety and maximize opportunities for role modeling and socialization. This research was supported by the Alberta Health Services Seniors Health Strategic Clinical Network and is registered in PROSPERO (ID#258179).

Predicting family physician physical activity electronic medical record inputs.

OBJECTIVE: To compare characteristics of patients with and without physical activity noted in primary care electronic medical records. METHODS: We used pan-Canadian family physician electronic medical record data from the Canadian Primary Care Sentinel Surveillance Network (CPSSSN) to compare patient and provider characteristics on one visit per patient selected at random. Since patients were nested by providers, univariate statistics were explored then a multilevel model was constructed. RESULTS: The dataset included 769,185 patients, of whom 14,828 (1.9%) had physical activity information documented. Male patients, aged 25-34.9, no comorbidities prior to the random visit date, moderate or elevated blood pressure risk categories prior to the random visit date, the least materially deprived quintile, and with median body mass index in the normal category prior to the random visit date had the most physical activity mentions. Of the 879 family physicians in the sample, just over half (56.1%) documented physical activity at least once across their patients. More female physicians and physicians who practised in academic sites documented physical activity. In a two-level logistic model to predict physical activity documented in the randomly selected visit: older than mean patient age, having fewer comorbidities, younger than mean family physician age, academic teaching sites, and electronic medical record systems were statistically significant covariates. CONCLUSIONS: This work adds to existing literature by describing the frequency and the patient and family physician characteristics of physical activity documentation in the Canadian primary care context. Overall, patient physical activity was rarely documented in electronic medical records.

Re-assessing the social climate of physical (in)activity in Canada.

Social-ecological models suggest that a strategy for increasing population physical activity participation is to reconstruct the "social climate" through changing social norms and beliefs about physical activity (PA). In this study, we assessed whether the PA social climate in Canada has changed over a five-year period after controlling for sociodemographic factors and PA levels. Replicating a survey administered in 2018, a sample of adults in Canada (n = 2,507) completed an online survey assessing social climate dimensions, including but not limited to descriptive and injunctive norms. Descriptive statistics were calculated, and binary logistic regressions were conducted to assess the associations of sociodemographic factors and year of the survey with social climate dimensions. Results suggest some social climate constructs are trending in a positive direction between 2018 and 2023. Physical inactivity was considered a serious public health concern by 49% of respondents, second to unhealthy diets (52%). Compared to those who participated in the 2018 survey, participants in 2023 were less likely to see others walking or wheeling in their neighbourhood (OR = 1.58, 95% CI: 1.41, 1.78), but more likely to see people exercising (OR = 0.82, 95% CI: 0.73, 0.92) and kids playing in their neighbourhood (OR = 0.75, 95% CI: 0.66, 0.85). No changes were reported between 2018 and 2023 in individuals' perceptions of whether physical inactivity is due to individual versus external factors (OR = 0.99, 95% CI: 0.87, 1.13). The findings of this work indicate a modest positive shift in some measured components of the social climate surrounding PA although attributing causes for these changes remain speculative.

Serial macromolecular crystallography at ALBA Synchrotron Light Source.

The increase in successful adaptations of serial crystallography at synchrotron radiation sources continues. To date, the number of serial synchrotron crystallography (SSX) experiments has grown exponentially, with over 40 experiments reported so far. In this work, we report the first SSX experiments with viscous jets conducted at ALBA beamline BL13-XALOC. Small crystals (15-30 µm) of five soluble proteins (lysozyme, proteinase K, phycocyanin, insulin and α-spectrin-SH3 domain) were suspended in lipidic cubic phase (LCP) and delivered to the X-ray beam with a high-viscosity injector developed at Arizona State University. Complete data sets were collected from all proteins and their high-resolution structures determined. The high quality of the diffraction data collected from all five samples, and the lack of specific radiation damage in the structures obtained in this study, confirm that the current capabilities at the beamline enables atomic resolution determination of protein structures from microcrystals as small as 15 µm using viscous jets at room temperature. Thus, BL13-XALOC can provide a feasible alternative to X-ray free-electron lasers when determining snapshots of macromolecular structures.

Serial macromolecular crystallography at ALBA Synchrotron Light Source. Erratum.

A revised version of Table 2 of Martin-Garcia et al. [J. Synchrotron Rad. (2022). 29, 896-907] is provided.

Macromolecular diffractive imaging using imperfect crystals.

The three-dimensional structures of macromolecules and their complexes are mainly elucidated by X-ray protein crystallography. A major limitation of this method is access to high-quality crystals, which is necessary to ensure X-ray diffraction extends to sufficiently large scattering angles and hence yields information of sufficiently high resolution with which to solve the crystal structure. The observation that crystals with reduced unit-cell volumes and tighter macromolecular packing often produce higher-resolution Bragg peaks suggests that crystallographic resolution for some macromolecules may be limited not by their heterogeneity, but by a deviation of strict positional ordering of the crystalline lattice. Such displacements of molecules from the ideal lattice give rise to a continuous diffraction pattern that is equal to the incoherent sum of diffraction from rigid individual molecular complexes aligned along several discrete crystallographic orientations and that, consequently, contains more information than Bragg peaks alone. Although such continuous diffraction patterns have long been observed--and are of interest as a source of information about the dynamics of proteins--they have not been used for structure determination. Here we show for crystals of the integral membrane protein complex photosystem II that lattice disorder increases the information content and the resolution of the diffraction pattern well beyond the 4.5-ångström limit of measurable Bragg peaks, which allows us to phase the pattern directly. Using the molecular envelope conventionally determined at 4.5 ångströms as a constraint, we obtain a static image of the photosystem II dimer at a resolution of 3.5 ångströms. This result shows that continuous diffraction can be used to overcome what have long been supposed to be the resolution limits of macromolecular crystallography, using a method that exploits commonly encountered imperfect crystals and enables model-free phasing.

Snapshot of an oxygen intermediate in the catalytic reaction of cytochrome c oxidase.

Cytochrome c oxidase (CcO) reduces dioxygen to water and harnesses the chemical energy to drive proton translocation across the inner mitochondrial membrane by an unresolved mechanism. By using time-resolved serial femtosecond crystallography, we identified a key oxygen intermediate of bovine CcO. It is assigned to the PR-intermediate, which is characterized by specific redox states of the metal centers and a distinct protein conformation. The heme a3 iron atom is in a ferryl (Fe4+ = O2-) configuration, and heme a and CuB are oxidized while CuA is reduced. A Helix-X segment is poised in an open conformational state; the heme a farnesyl sidechain is H-bonded to S382, and loop-I-II adopts a distinct structure. These data offer insights into the mechanism by which the oxygen chemistry is coupled to unidirectional proton translocation.

Investigation of movement-related behaviors and energy compensation in people living with liver disease: A scoping review.

The importance of integrated movement behaviours (MB, i.e., physical activity [PA], sedentary behaviour, and sleep) and their interdependence for health has been recently discussed in the literature. The proposition that the amount of time spent in any one of these behaviours may impact the amount of time spent in another is supported by the ActivityStat hypothesis. The aim of this review is to (1) to assess whether individuals with liver disease display MB and/or energy (i.e., total energy expenditure [EE], basal EE, resting EE, and activity EE) compensation throughout the day and/or days; and (2) to examine whether a prescribed PA intervention triggers compensatory responses. Documents were included if they focused on people living with liver disease; analysed MB and/or EE components; were data-based; and were published in English. Fifteen documents were included in the final synthesis. The one finding that addressed research question 1 showed no compensatory response. As for research question 2, most of the findings suggest no compensation effects in response to a PA intervention. There is insufficient evidence to support the ActivityStat hypothesis in people living with liver disease. Further research should be conducted to test this hypothesis using standardized methodological procedures.

Relationships Between Physical Activity, Boredom Proneness, and Subjective Well-Being Among U.K. Adults During the COVID-19 Pandemic.

This investigation sought to examine physical activity (PA) as a potential determinant of chronic boredom and associated well-being within the context of COVID-related restrictions. A representative sample of U.K. adults (N = 1,521) completed a survey on June 1, 2020. Bivariate analyses demonstrated that individuals who met guidelines and maintained or increased PA scored higher on life satisfaction, worthwhileness, and happiness and lower on anxiety (i.e., indicators of well-being) and boredom proneness (d = 0.13-0.43). Boredom proneness was correlated with all indicators of well-being (r = .38-.54). A series of regression models revealed that PA predicted lower boredom proneness and better life satisfaction, worthwhileness, and happiness. Boredom proneness accounted for the covariance between PA and well-being. Prospective research is needed to confirm causality of the observed relationships.

Stationary Behavior and the Step-Defined Sedentary Lifestyle Index in Older Adults After Total Knee Arthroplasty.

OBJECTIVES: To measure stationary behavior in a cohort of older adults after total knee arthroplasty (TKA) and determine the clinical utility of the step-defined sedentary lifestyle index (SLI) as a measure of stationary behavior after TKA. DESIGN: Cross-sectional measurement study. SETTING: Participants were recruited from a community intake clinic for hip and knee surgeries. PARTICIPANTS: Sixty-five older adults 3 months after TKA (N=65). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stationary behaviors, including stationary time, stationary bouts, breaks from stationary time, and the proportion of participants meeting the SLI, were measured in older adults 3 months post TKA using accelerometry. A 2-way analysis of variance test (α=0.05) was conducted to determine the effects of SLI (<5000 or ≥5000 daily steps) and possible interactions with sex on stationary behavior. RESULTS: Participants spent 80% (13.17±2.3h) of their waking time in stationary time and had an average of 6.06 bouts of stationary time >30 minutes per day. Forty (61.5%) of the participants fell below the SLI of 5000 steps/d. SLI had significant effects on both waking stationary time (P<.001) and number of breaks in stationary time (P<.001), with participants taking <5000 daily steps having longer stationary times and fewer breaks in stationary time. Sex had a significant effect on the number of breaks in stationary time (P=.04), with men (n=23, 35%) reporting more breaks than women (n=42, 65%) (mean difference 13.36; 95% confidence interval, -2.67 to 18.69). No interactions were found between SLI and sex. CONCLUSIONS: Both women and men had high levels of stationary behavior 3 months post TKA. The SLI discriminated waking stationary time and breaks in stationary time and may have clinical utility in measurement of stationary behavior.

Validity of Tools to Measure Physical Activity in Older Adults Following Total Knee Arthroplasty.

Few validated tools exist for measuring physical activity following total knee arthroplasty (TKA) despite the importance of returning to sufficient levels of physical activity post-TKA to achieve health benefits. This study examined the validity of two clinical measures-the Fitbit, a commercially available personal activity monitor, and the Community Healthy Activities Model Program for Seniors (CHAMPS), a self-report questionnaire-compared with a reference standard accelerometer, the SenseWearTM Armband (SWA). At 6-month post-TKA, 47 participants wore the Fitbit and SWA for 4 days and then completed the CHAMPS. Moderate-to-good correlation was observed between the Fitbit and SWA for steps (intraclass correlation coefficient [ICC] = .79), energy expenditure (ICC = .78), and energy expenditure <3 METS (ICC = .79). Poor-to-moderate correlation was observed between the CHAMPS and SWA (ICC = .43) with the questionnaire reporting lower daily energy expenditures than the SWA. Results showed that Fitbit may be a reasonable measurement tool to measure steps and energy expenditures in older adults following TKA.

Assessing Patient Proficiency with Internet-Connected Technology and Their Preferences for E-Health in Cirrhosis.

There is a rapidly evolving need for e-health to support chronic disease self-management and connect patients with their healthcare teams. Patients with cirrhosis have a high symptom burden, significant comorbidities, and a range of psychological and cognitive issues. Patients with cirrhosis were assessed for their readiness and interest in e-health. Adults attending one of two outpatient cirrhosis clinics in Alberta were recruited. Eligible participants were not required to own or have experience with digital technologies or the Internet. Medical history, socioeconomic status, and attitudes regarding e-health, the Computer Proficiency Questionnaire, and the Mobile Device Proficiency Questionnaire were used to describe participants' knowledge and skills. Of the 117 recruited patients, 68.4% owned a computer and 84.6% owned a mobile device. Patients had mean proficiency scores of 72.8% (SD 25.9%) and 69.3% (SD 26.4%) for these devices, respectively. In multiple regression analyses, significant predictors of device proficiency were age, education, and household income. Most patients (78.7%) were confident they could participate in videoconferencing after training and most (61.5%) were interested in an online personalized health management program. This diverse group of patients with cirrhosis had technology ownership, proficiency, and online behaviours similar to the general population. Moreover, the patients were very receptive to e-health if training was provided. This promising data is timely given the unique demands of COVID-19 and its influence on self-management and healthcare delivery to a vulnerable population.

3D printing of gas-dynamic virtual nozzles and optical characterization of high-speed microjets.

Gas dynamic virtual nozzles (GDVNs) produce microscopic flow-focused liquid jets and droplets and play an important role at X-ray free-electron laser (XFEL) facilities where they are used to steer a stream of hydrated biomolecules into an X-ray focus during diffraction measurements. Highly stable and reproducible microjet and microdroplets are desired, as are flexible fabrication methods that enable integrated mixing microfluidics, droplet triggering mechanisms, laser illumination, and other customized features. In this study, we develop the use of high-resolution 3D nano-printing for the production of monolithic, asymmetric GDVN designs that are difficult to fabricate by other means. We also develop a dual-pulsed nanosecond image acquisition and analysis platform for the characterization of GDVN performance, including jet speed, length, diameter, and directionality, among others. We show that printed GDVNs can form microjets with very high degree of reproducibility, down to sub-micron diameters, and with water jet speeds beyond 170 m/s.

Inversion of Many-Beam Bragg Intensities for Phasing by Iterated Projections: Removal of Multiple Scattering Artifacts from Diffraction Data.

An iterated projection algorithm (N-Phaser) is developed that reconstructs a scattering potential from N-beam multiple Bragg scattered intensities. The method may be used to eliminate multiple scattering artifacts from electron diffraction data, solving the phase problem and increasing the thicknesses of samples used in materials science, solid-state chemistry, and small molecule crystallography. For high-energy transmission electron diffraction, we show that the algorithm recovers accurate complex structure factors from a wide range of thicknesses, orientations, and relativistic beam energies, and does not require known thickness or atomic-resolution data if sufficient multiple scattering occurs. Extensions to Cryo-electron microscopy and Micro-electron diffraction are suggested.

Impact of the COVID-19 virus outbreak on movement and play behaviours of Canadian children and youth: a national survey.

BACKGROUND: Healthy childhood development is fostered through sufficient physical activity (PA; including time outdoors), limiting sedentary behaviours (SB), and adequate sleep; collectively known as movement behaviours. Though the COVID-19 virus outbreak has changed the daily lives of children and youth, it is unknown to what extent related restrictions may compromise the ability to play and meet movement behaviour recommendations. This secondary data analysis examined the immediate impacts of COVID-19 restrictions on movement and play behaviours in children and youth. METHODS: A national sample of Canadian parents (n = 1472) of children (5-11 years) or youth (12-17 years) (54% girls) completed an online survey that assessed immediate changes in child movement and play behaviours during the COVID-19 outbreak. Behaviours included PA and play, SB, and sleep. Family demographics and parental factors that may influence movement behaviours were assessed. Correlations between behaviours and demographic and parental factors were determined. For open-ended questions, word frequency distributions were reported. RESULTS: Only 4.8% (2.8% girls, 6.5% boys) of children and 0.6% (0.8% girls, 0.5% boys) of youth were meeting combined movement behaviour guidelines during COVID-19 restrictions. Children and youth had lower PA levels, less outside time, higher SB (including leisure screen time), and more sleep during the outbreak. Parental encouragement and support, parental engagement in PA, and family dog ownership were positively associated with healthy movement behaviours. Although families spent less time in PA and more time in SB, several parents reported adopting new hobbies or accessing new resources. CONCLUSIONS: This study provides evidence of immediate collateral consequences of the COVID-19 outbreak, demonstrating an adverse impact on the movement and play behaviours of Canadian children and youth. These findings can guide efforts to preserve and promote child health during the COVID-19 outbreak and crisis recovery period, and to inform strategies to mitigate potential harm during future pandemics.

Acute lymphoblastic leukemia clonal distribution between bone marrow and peripheral blood.

Acute lymphoblastic leukemia (ALL) is often composed of numerous subclones. Here we test whether the clonal composition of the blood is representative of the bone marrow at leukemia onset. Using ultra-deep IGH sequencing, we detected 28 clones across 16 patients; 5/28 were only in the marrow. In four patients, the most abundant clones differed between sites, including three in which the dominant medullary clones were minimally detectable in the blood. These findings demonstrate that the peripheral blood often underrepresents the genetic heterogeneity in a B-ALL and highlight the potential impact of tissue site selection on the detection of minor subclones.

A new anthropometric index to predict percent body fat in young adults.

OBJECTIVE: To propose a new anthropometric index that can be employed to better predict percent body fat (PBF) among young adults and to compare with current anthropometric indices. DESIGN: Cross-sectional. SETTING: All measurements were taken in a controlled laboratory setting in Seoul (South Korea), between 1 December 2015 and 30 June 2016. PARTICIPANTS: Eighty-seven young adults (18-35 years) who underwent dual-energy x-ray absorptiometry (DXA) were used for analysis. Multiple regression analyses were conducted to develop a body fat index (BFI) using simple demographic and anthropometric information. Correlations of DXA measured PBF (DXA_PBF) with previously developed anthropometric indices and the BFI were analysed. Receiver operating characteristic curve analyses were conducted to compare the ability of anthropometric indices to identify obese individuals. RESULTS: BFI showed a strong correlation with DXA_PBF (r = 0·84), which was higher than the correlations of DXA_PBF with the traditional (waist circumference, r = 0·49; waist to height ratio, r = 0·68; BMI, r = 0·36) and alternate anthropometric indices (a body shape index, r = 0·47; body roundness index, r = 0·68; body adiposity index, r = 0·70). Moreover, the BFI showed higher accuracy at identifying obese individuals (area under the curve (AUC) = 0·91), compared with the other anthropometric indices (AUC = 0·71-0·86). CONCLUSIONS: The BFI can accurately predict DXA_PBF in young adults, using simple demographic and anthropometric information that are commonly available in research and clinical settings. However, larger representative studies are required to build on our findings.