Morphology and line tension of twist disclinations in a nematic liquid crystal.

We deploy optical microscopy with and without an applied magnetic field to characterize the three-dimensional morphology and measure the line tension of twist disclinations in twisted nematic liquid crystal (LC) sample cells. Twist disclinations are generated by quenching the LC, 5CB (4-cyano-4'-pentylbiphenyl), into the nematic phase; 5CB is confined between substrates with in-plane anchoring directions perpendicular to one another. The disclinations form loops separating domains of opposite twist handedness.

Prospective associations of genetic susceptibility to high blood pressure and muscle strength with incident cardiovascular disease outcomes.

Background: This study explored the prospective associations of genetic susceptibility to high blood pressure (BP) and muscle strength with cardiovascular disease (CVD) mortality, incident coronary heart disease (CHD) and incident stroke.

Methods: This study included 349 085 white British individuals from the UK Biobank study. Genetic risk of high BP was estimated using a weighted polygenic risk score that incorporated 136 and 135 nonoverlapping single-nucleotide polymorphisms for systolic BP and diastolic BP, respectively.

Associations of movement behaviours and dietary intake with arterial stiffness: results from the ORISCAV-LUX 2 cross-sectional study.

Objective: Adopting a physically active lifestyle and maintaining a diet rich in antioxidants can reduce the risk of vascular diseases. Arterial stiffness is an early marker for cardiovascular diseases, indicating vascular damage. This study investigates the relationship between physical activity (PA), sedentary behaviour (SB), dietary antioxidant, trace elements intake and vascular health in men and women, with a focus on pulse wave velocity (PWV), the gold standard for assessing arterial stiffness.

Deep learning of movement behavior profiles and their association with markers of cardiometabolic health.

Background: Traditionally, existing studies assessing the health associations of accelerometer-measured movement behaviors have been performed with few averaged values, mainly representing the duration of physical activities and sedentary behaviors. Such averaged values cannot naturally capture the complex interplay between the duration, timing, and patterns of accumulation of movement behaviors, that altogether may be codependently related to health outcomes in adults. In this study, we introduce a novel approach to visually represent recorded movement behaviors as images using original accelerometer outputs.

Magnetic-field-driven director configuration transitions in radial nematic liquid crystal droplets.

We study the director configurations of nematic liquid crystal (NLC) droplets with homeotropic anchoring in a magnetic field and report observation of a magnetic-field-driven transition from a deformed radial to an axial-with-defect configuration. Magnetic-field-induced transitions in NLC droplets differ fundamentally from the traditional planar Freedericksz transition due to the spherical droplet geometry and resulting topological defect. This transition has been studied theoretically, but the director configurations and mechanism of defect evolution in an applied magnetic field have yet to be observed experimentally.

Ten-Year Changes in the Physical Activity and Sedentary Behaviors of Adults: An Analysis of the 2 Cross-Sectional Observation of Cardiovascular Risk Factors in Luxembourg Studies.

Background: Monitoring population physical activity (PA) and sedentary behavior over time is important to guide public health actions. The objective of this study was to investigate the changes in PA and sedentary behavior of adult residents in Luxembourg over 10 years. We also investigated variations in change over time across sociodemographic subgroups.

Arterial stiffness and the reallocation of time between device-measured 24-hour movement behaviours: A compositional data analysis.

Background And Aims: Arterial stiffness predicts cardiovascular morbidity and mortality. We aimed to quantify the differences in arterial stiffness associated with reallocating time between 24-h movement behaviours.

Methods: This observational cross-sectional study included Luxembourg residents aged 25-79y who each provided ≥4 valid days of triaxial accelerometry (n = 1001).

Sociodemographic, temporal and bedtime routine correlates of sleep timing and duration in South Asian and white children: A Born in Bradford study.

Objective: The study aimed to examine sociodemographic, temporal and bedtime routine correlates of parent-reported sleep duration and timing in a biethnic sample of 18 month and 36 month old children from a disadvantaged location.

Methods: Between October 2010 and September 2012, parents completed a bespoke three day sleep diary when their child was approximately 18 months ( = 276) and 36 months of age  = 262) (45.1% South Asian; 54.

Substituting device-measured sedentary time with alternative 24-hour movement behaviours: compositional associations with adiposity and cardiometabolic risk in the ORISCAV-LUX 2 study.

Background: There is a considerable burden of sedentary time in European adults. We aimed to quantify the differences in adiposity and cardiometabolic health associated with theoretically exchanging sedentary time for alternative 24 h movement behaviours.

Methods: This observational cross-sectional study included Luxembourg residents aged 18-79 years who each provided  ≥ 4 valid days of triaxial accelerometry (n = 1046).

Device-measured physical activity and sedentary time in a national sample of Luxembourg residents: the ORISCAV-LUX 2 study.

Background: Existing information about population physical activity (PA) levels and sedentary time in Luxembourg are based on self-reported data.

Methods: This observational study included Luxembourg residents aged 18-79y who each provided ≥4 valid days of triaxial accelerometry in 2016-18 (n=1122). Compliance with the current international PA guideline (≥150 min moderate-to-vigorous PA (MVPA) per week, irrespective of bout length) was quantified and variability in average 24h acceleration (indicative of PA volume), awake-time PA levels, sedentary time and accumulation pattern were analysed by linear regression.

Associations Between Wearable-Specific Indicators of Physical Activity Behaviour and Insulin Sensitivity and Glycated Haemoglobin in the General Population: Results from the ORISCAV-LUX 2 Study.

Background: Parameters derived from an acceleration signal, such as the time accumulated in sedentary behaviour or moderate to vigorous physical activity (MVPA), may not be sufficient to describe physical activity (PA) which is a complex behaviour. Incorporating more advanced wearable-specific indicators of PA behaviour (WIPAB) may be useful when characterising PA profiles and investigating associations with health. We investigated the associations of novel objective measures of PA behaviour with glycated haemoglobin (HbA1c) and insulin sensitivity (Quicki index).

Orientational order of dyes in a lyotropic chromonic liquid crystal.

Absorption measurements allow the orientational order parameter of four dyes in the lyotropic chromonic liquid crystal di-sodium cromoglycate (DSCG) to be determined. The dye order parameters are small, except for dyes that intercalate between the DSCG molecules of the rod-like assemblies. The dye order parameters decrease with increasing temperature faster than the nematic order parameter of the DSCG assemblies.

Associations between insomnia and pregnancy and perinatal outcomes: Evidence from mendelian randomization and multivariable regression analyses.

Background: Insomnia is common and associated with adverse pregnancy and perinatal outcomes in observational studies. However, those associations could be vulnerable to residual confounding or reverse causality. Our aim was to estimate the association of insomnia with stillbirth, miscarriage, gestational diabetes (GD), hypertensive disorders of pregnancy (HDP), perinatal depression, preterm birth (PTB), and low/high offspring birthweight (LBW/HBW).

Effect of a 16-week multi-level classroom standing desk intervention on cognitive performance and academic achievement in adolescents.

The replacement of traditional classroom desks for active-permissive desks has been tested to reduce sitting time during classes. However, their impact on other domains is still unclear. We aimed to verify the potential effects of a classroom standing desk intervention on cognitive function and academic achievement in 6th-grade students.

Focal conic flowers, dislocation rings, and undulation textures in smectic liquid crystal Janus droplets.

Liquid crystalline phases of matter often exhibit visually stunning patterns or textures. Mostly, these liquid crystal (LC) configurations are uniquely determined by bulk LC elasticity, surface anchoring conditions, and confinement geometry. Here, we experimentally explore defect textures of the smectic LC phase in unique confining geometries with variable curvature.

Theory of director fluctuations about a hedgehog defect in a nematic drop.

We present calculations of eigenmode energies and wave functions of both azimuthal and polar distortions of the nematic director relative to a radial hedgehog trapped in a spherical drop with a smaller concentric spherical droplet at its core. All surfaces interior to the drop have perpendicular (homeotropic) boundary conditions. We also calculate director correlation functions and their relaxation times.

Giant director fluctuations in liquid crystal drops.

We report the discovery and elucidation of giant spatiotemporal orientational fluctuations in nematic liquid crystal drops with radial orientation of the nematic anisotropy axis producing a central "hedgehog" defect. We study the spatial and temporal properties of the fluctuations experimentally using polarized optical microscopy, and theoretically, by calculating the eigenspectrum of the Frank elastic free energy of a nematic drop of radius R_{2}, containing a spherical central core of radius R_{1} and constrained by perpendicular boundary conditions on all surfaces. We find that the hedgehog defect with radial orientation has a complex excitation spectrum with a single critical mode whose energy vanishes at a critical value μ_{c} of the ratio μ=R_{2}/R_{1}.

Association of parents' physical activity and weight status with obesity and metabolic risk of their offspring.

Our aim was to analyze the joint association of parental characteristics and offspring obesity indicators with metabolic risk in adolescents. A cross-sectional study was carried out with 972 adolescents and their parents. We observed that overweight adolescents who have a normal weight mother show lower metabolic risk in comparison with their counterparts with overweight mothers.

Correlates of screen-based behaviors among adults from the 2019 Brazilian National Health Survey.

We aimed to investigate correlates of TV viewing and other types of screen-based behaviors in a nationally representative sample of Brazilian adults. In the 2019 Brazilian National Health Survey (including 88,509 adults), TV viewing time and other types of screen behaviors (computer, tablet, and cellphone use) were self-reported and different geographical, sociodemographic, behavioral, and health status factors were investigated as potential correlates. Multinomial logistic regression models were used for the main analyses.

Rods in a lyotropic chromonic liquid crystal: emergence of chirality, symmetry-breaking alignment, and caged angular diffusion.

In lyotropic chromonic liquid crystals (LCLCs), twist distortion of the nematic director costs much less energy than splay or bend distortion. This feature leads to novel mirror-symmetry breaking director configurations when the LCLCs are confined by interfaces or contain suspended particles. Spherical colloids in an aligned LCLC nematic phase, for example, induce chiral director perturbations ("twisted tails").

Cross-sectional and prospective associations of sleep duration and bedtimes with adiposity and obesity risk in 15 810 youth from 11 international cohorts.

Objectives: To investigate associations of bedtimes and sleep durations with adiposity levels in children and adolescents.

Methods: Individual data were pooled for 12 247 children (5819 with follow-up adiposity at 2.3 ± 1.

Independent associations of sleep timing, duration and quality with adiposity and weight status in a national sample of adolescents: The UK Millennium Cohort Study.

Short sleep appears to elevate obesity risk in youth; however, sleep is a multidimensional construct, and few studies have investigated parameters beyond duration. The objective of this study was to investigate if sleep onset time, duration, latency and night waking frequency are independently associated with adiposity and weight status in UK adolescents. This was a cross-sectional observational study of 10,619, 13-15 years olds.

Associations of diarised sleep onset time, period and duration with total and central adiposity in a biethnic sample of young children: the Born in Bradford observational cohort study.

Objectives: To investigate associations of parent-reported sleep characteristics with adiposity levels in a biethnic sample of young children.

Design: A cross-sectional observational study.

Setting: The Born in Bradford 1000 study, UK.

Interplay between Confinement, Twist Elasticity, and Intrinsic Chirality in Micellar Lyotropic Nematic Liquid Crystals.

Recent studies have shown that lyotropic nematic liquid crystals (LLCs) are exceptional in their viscoelastic behavior. In particular, LLCs display a remarkable softness to twist deformations, which may lead to chiral director configurations under achiral confinement despite the absence of intrinsic chirality. The twisted escaped radial (TER) and the twisted polar (TP) are the two representative reflection symmetry breaking director configurations in the case of cylindrical confinement with homeotropic anchoring.

A chiral-racemic lyotropic chromonic liquid crystal system.

The two main classes of liquid crystals are thermotropic (containing no solvent) and lyotropic (containing solvent). Both of these classes possess the nematic phase, the most simple of liquid crystal phases with only uniaxial orientational order. For both of these classes, if the constituent molecules are chiral or if a chiral dopant is added, the preferred direction of orientation rotates in helical fashion in what is called the chiral nematic phase.