1,462 research outputs found
Analysis of a G-Protein Coupled Receptor, CB2
The CB2 G-protein coupled receptors (GPCR) is found in the brainstem & hippocampus and is devoid of psychotropic effects but is less studied than the CB1 receptor. CB2 is inducible in CNS microglia following inflammation or injury, indicating a role in pain response. Here we sought to analyze CB2 using ChimeraX structures and overcome GPCR protein insolubility in extraction. The pET28a-CNR2, plasmid created and transformed into E.coli pLysS, was confirmed by restriction digest. Purification of CB2 micelles was achieved by affinity chromatography with detergent (43 kD). We aim to utilize nanodiscs to stabilize CB2, allowing studies of the molecular underpinnings informing treatment options
Cardiovascular disease and hypertension in sub-Saharan Africa : burden, risk and interventions
Cardiovascular disease, including stroke, heart failure and kidney disease, have been common in sub-Saharan Africa for many years and rapid urbanization is causing an upsurge of ischaemic heart disease and metabolic disorders. At least two thirds of cardiovascular deaths now occur in low-and-middle-income countries, bringing a double burden of disease to poor and developing world economies. High blood pressure (or hypertension) is by far the commonest underlying risk factor for cardiovascular disease. Its prevention, detection, treatment and control in sub-Saharan Africa are haphazard and sub-optimal. This is due to a combination of lack of resources and healthcare systems, non-existent effective preventive strategies at a population level, lack of sustainable drug therapy and barriers to complete adherence to prescribed medications. The economic impact in regard to loss of productive years of life and the need to divert scarce resources to tertiary care is substantial
Systematic review and meta-analysis of randomised controlled trials on the effects of potassium supplements on serum potassium and creatinine
Objectives: High potassium intake could prevent stroke, but supplementation is considered hazardous. We assessed the effect of oral potassium supplementation on serum or plasma potassium levels and renal function.
Setting: We updated a systematic review of the effects of potassium supplementation in randomised clinical trials carried out worldwide, published in 2013, extending it to July 2015. We followed the PRISMA guidelines.
Participants: Any individual taking part in a potassium supplementation randomised clinical trial. Studies included met the following criteria: randomised clinical trials, potassium supplement given and circulating potassium levels reported.
Intervention: Oral potassium supplementation.
Primary outcome measures: Serum or plasma potassium and serum or plasma creatinine.
Results: A total of 20 trials (21 independent groups) were included (1216 participants from 12 different countries). All but 2 were controlled (placebo n=16, control n=2). Of these trials, 15 were crossover, 4 had a parallel group and 1 was sequential. The duration of supplementation varied from 2 to 24 weeks and the amount of potassium given from 22 to 140 mmol/day. In the pooled analysis, potassium supplementation caused a small but significant increase in circulating potassium levels (weighted mean difference (WMD) 0.14 mmol/L, 95% CI 0.09 to 0.19, p<1×10−5), not associated with dose or duration of treatment. The average increase in urinary potassium excretion was 45.75 mmol/24 hours, 95% CI 38.81 to 53.69, p<1×10−5. Potassium supplementation did not cause any change in circulating creatinine levels (WMD 0.30 µmol/L, 95% CI −1.19 to 1.78, p=0.70).
Conclusions: In short-term studies of relatively healthy persons, a moderate oral potassium supplement resulted in a small increase in circulating potassium levels and no change in renal function
Sleep and Cognition
Sleep is an ancestral and primitive behaviour, an important part of life thought to be essential for restoration of body and mind. As adults, we spend approximately a third of our lives asleep and as we progress through life there are certain shifts in sleep architecture, most notably in sleep quantity. These biological or physiological age-dependent changes in sleep are well documented [1], and alongside the shifts in sleep architecture there is an increased susceptibility to certain sleep disorders.
Sleep disturbances and sleep deprivation are common in modern society. Most studies show that since the beginning of the century, populations have been subjected to a steady constant decline in the number of hours devoted to sleep. This is due to changes in a variety of environmental and social conditions (e.g. less dependence on daylight for most activities, extended shift work and 24/7 round-the-clock activities
Knowledge and degree of training of Primary Education teachers in relation to ICT taught to disabled students
The integration of Information and Communication Technologies (ICT) into the inclusive classroom requires competent teaching staff from both the technological and pedagogical points of view. Within this context, and with the aim of looking at one of these theoretical premises, this study aimed to identify the degree of training and technological knowledge of primary school teachers in Spain with respect to the use of ICT with individuals with disabilities (functional diversity). A descriptive ex post-facto research method was used, where the sample comprised 777 teachers. An ad-hoc questionnaire was used as the data-collection instrument. The results revealed the low skill levels of the teachers with respect to the use of ICT with students with disabilities, where the level of training of the teaching staff was determined by personal (gender, age), professional (teaching experience) or educational (qualifications) variables. The findings of this study point to the need for teacher training that instructs teachers on the use of ICT in order to favour the learning and educational innovation of students with disabilities
Improvements in BepiColombo and JUICE radio science experiments with a multi-station tracking configuration for the reduction of Doppler noise
Radio science experiments for planetary geodesy mostly rely on measurements of the Doppler shift of microwave signals sent to a spacecraft by an Earth station, and retransmitted back coherently in phase to the same antenna (two-way link). The retransmitted signal can also be received by a different station in a listen-only configuration (three-way link). In state-of-the-art tracking systems, such as the ones will be used on the future ESA's missions JUICE and BepiColombo, the Doppler error budget is dominated by local noise sources arising at the ground-station, in particular tropospheric scintillation and unmodeled motions of the antenna's structure. In this work, a novel technique aimed at reducing these disturbances is analyzed, with particular emphasis on its benefits to BepiColombo's and JUICE's radio science experiments. The method, referred to as Time-Delay Mechanical-noise Cancellation (TDMC), relies on simultaneous two-way and three-way spacecraft tracking, the latter employing a stiffer listen-only antenna with better mechanical stability and located in a favorable dry region more immune to tropospheric noise. In fact, a proper linear combination of time-shifted observables from the two-way and three-way links can replace local noises of the two-way ground-station with those coming from the listen-only antenna, translating into increased accuracy of the final measurements, while preserving the original Doppler content. We show the results of covariance analyses performed with a multi-arc weighted least square estimator for the entire BepiColombo's Hermean phase and JUICE's flybys of Callisto. We compare the two solutions obtained with and without the application of the TDMC technique. For BepiColombo and JUICE radio science experiments, the two-way links are baselined from the 35-m DSA-3 (Malargüe, Argentina) and the 34-m DSS 25 (Goldstone, California). For the three-way link, we select the 12-m Large Latin American Millimeter Array (LLAMA) antenna for three reasons: 1) its mechanical rigidity with respect to large beam-waveguide antennas, 2) its unique position in the extremely dry Puna de Atacama desert, that assures low tropospheric noise, and 3) its limited longitudinal separation from the two other ground-stations, granting sufficient common visibility time to perform the requested combination of the observables. Besides its noise-reduction effect, enabling unprecedented levels of accuracy on Doppler measurements, TDMC provides also a back-up for unique events: a crucial satellite flyby or a specific passage over a site of particular geophysical interest. Indeed, measurements become virtually independent of unfavorable meteorological conditions at the transmitting station
Sleep duration and incidence of obesity in infants, children and adolescents : a systematic review and meta-analysis of prospective studies
Study Objective:
To assess the prospective relationship between sleep and obesity in a paediatric population.
Methods:
We performed a systematic search using PubMed, Embase, Web of Science and Cochrane (up to 25th September 2017). Included studies were prospective, had follow-up >1 year, had duration of sleep at baseline, and measures of incidence of overweight or obesity and/or changes in body mass index (BMI) z-score and BMI during follow-up. We extracted relative risks or changes in BMI z-score or BMI and 95% confidence intervals (CI) and pooled them using a random effect model. Results: Forty-two studies were included but, as there was significant heterogeneity, results are presented by age strata. Short sleep was associated with a greater risk of developing overweight or obesity in infancy (7 Studies, 14 738 participants, RR: 1.40; 95% CI 1.19 to 1.65; p<0.001), early childhood (8 Studies, 31 104 participants, RR: 1.57; 1.40 to 1.76; p<0.001), middle childhood (3 studies, 3 005 participants, RR: 2.23; 2.18 to 2.27; p<0.001) and adolescence (3 studies, 26 652 participants, RR: 1.30; 1.11 to 1.53; p<0.002). Sleep duration was also associated with a significant change in BMI z-score (14 studies, 18 cohorts, 31 665 participants) (mean difference -0.03; -0.04 to -0.01 per h sleep; P=0.001) and in BMI (16 studies, 24 cohorts, 24 894 participants) (mean difference -0.03 kg/m2; -0.04 to -0.01 for every h of increase in sleep; P=0.001).
Conclusions:
Short sleep duration is a risk factor or marker of the development of obesity in infants, children and adolescents
Systematic review and meta-analyses of the relationship between short sleep and incidence of obesity and effectiveness of sleep interventions on weight gain in preschool children
The aim of this study is to determine (a) whether short sleep is associated with the incidence of obesity and (b) whether interventions beneficial for sleep reduce weight gain in preschool children. We systematically searched PubMed, Embase, Web of Science and Cochrane up to 12/09/2019. (a) Studies that were included were prospective, had follow‐up ≥1 year, with sleep duration at baseline and required outcome measures. (b) Intervention trials with sleep intervention and measures of overweight or obesity were included. Data were extracted according to PRISMA guidelines. (a) The risk of developing overweight/obesity was greater in short sleeping children (13 studies, 42 878 participants, RR: 1.54; 95% CI, 1.33 to 1.77; p < 0.001). Sleep duration was associated with a significant change in BMI z‐score (10 studies, 11 cohorts and 29 553 participants) (mean difference: −0.02 unit per hour sleep; −0.03 to −0.01; p < 0.001). (b) Four of the five intervention studies reported improved outcomes: for BMI (−0.27 kg/m2; −0.50 to −0.03; p = 0.03); for BMI z‐score (−0.07 unit; −0.12 to −0.02; p = 0.006). Short sleep duration is a risk factor or marker of the development of obesity in preschool children. Intervention studies suggest that improved sleep may be beneficially associated with a reduced weight gain in these children
Gender-specific associations of short sleep duration with prevalent and incident hypertension : the Whitehall II Study
Sleep deprivation (5 hour per night) was associated with a higher risk of hypertension in middle-aged American adults but not among older individuals. However, the outcome was based on self-reported diagnosis of incident hypertension, and no gender-specific analyses were included. We examined cross-sectional and prospective associations of sleep duration with prevalent and incident hypertension in a cohort of 10 308 British civil servants aged 35 to 55 years at baseline (phase 1: 1985-1988). Data were gathered from phase 5 (1997-1999) and phase 7 (2003-2004). Sleep duration and other covariates were assessed at phase 5. At both examinations, hypertension was defined as blood pressure 140/90 mm Hg or regular use of antihypertensive medications. In cross-sectional analyses at phase 5 (n5766), short duration of sleep (5 hour per night) was associated with higher risk of hypertension compared with the group sleeping 7 hours, among women (odds ratio: 2.01; 95% CI: 1.13 to 3.58), independent of confounders, with an inverse linear trend across decreasing hours of sleep (P0.003). No association was detected in men. In prospective analyses (mean follow-up: 5 years), the cumulative incidence of hypertension was 20.0% (n740) among 3691 normotensive individuals at phase 5. In women, short duration of sleep was associated with a higher risk of hypertension in a reduced model (age and employment) (6 hours per night: odds ratio: 1.56 [95% CI: 1.07 to 2.27]; 5 hour per night: odds ratio: 1.94 [95% CI: 1.08 to 3.50] versus 7 hours). The associations were attenuated after accounting for cardiovascular risk factors and psychiatric comorbidities (odds ratio: 1.42 [95% CI: 0.94 to 2.16]; odds ratio: 1.31 [95% CI: 0.65 to 2.63], respectively). Sleep deprivation may produce detrimental cardiovascular effects among women. (Hypertension. 2007;50:694-701.) Key Words: sleep duration blood pressure hypertension gender differences confounders comorbiditie
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