127 research outputs found
Prevention of overweight and hypertension through cardiorespiratory fitness and extracurricular sport participation among South African schoolchildren
Hypertension and overweight are growing public health concerns in school-aged children. We examined whether cardiorespiratory fitness and sport participation contribute to the prevention of hypertension and overweight. We conducted a cluster-randomized controlled trial with 853 children aged 8-13 years in eight primary schools in Port Elizabeth, South Africa. Cardiorespiratory fitness, sport participation, body mass index, and blood pressure were assessed at baseline and after a physical activity intervention, which took place at two time-points (July-September 2015 and February-April 2016) for 10 weeks each. Mixed logistic regressions were employed to analyze the data. At baseline, 18.8% of the children were classified as overweight/obese and 13.5% as hypertensive. High cardiorespiratory fitness and high sport participation were negatively associated with overweight/obesity, while high sport participation was associated with lower risk for hypertension. Longitudinally, normal weight children who initially had higher cardiorespiratory fitness showed less decrease in this variable, while those who participated in the physical activity intervention were less likely to become overweight/obese. High cardiorespiratory fitness and sport participation are linked with children's weight status. Children who are fit and participate regularly in sport outside school hours are less likely to be hypertensive. Our findings highlight the importance of regular extracurricular physical activity and maintaining cardiorespiratory fitness levels
The death of massive stars - I. Observational constraints on the progenitors of type II-P supernovae
We present the results of a 10.5 yr, volume limited (28 Mpc) search for
supernova (SN) progenitor stars. We compile all SNe discovered within this
volume (132, of which 27% are type Ia) and determine the relative rates of each
sub-type from literature studies : II-P (59%), Ib/c (29%), IIb (5%), IIn (4%)
and II-L (3%). Twenty II-P SNe have high quality optical or near-IR
pre-explosion images that allow a meaningful search for the progenitor stars.
In five cases they are clearly red supergiants, one case is unconstrained, two
fall on compact coeval star clusters and the other twelve have no progenitor
detected. We review and update all the available data for the host galaxies
(distance, metallicity and extinction) and determine masses and upper mass
estimates using the STARS stellar evolutionary code and a single consistent
homogeneous method. A maximum likelihood calculation suggests that the minimum
stellar mass for a type II-P to form is m(min)=8.5 +1/-1.5 Msol and the maximum
mass for II-P progenitors is m(max)=16.5 +/- 1.5 Msol, assuming a Salpeter
initial mass function (in the range Gamma = -1.35 +0.3/-0.7). The minimum mass
is consistent with current estimates for white dwarf progenitor masses, but the
maximum mass does not appear consistent with massive star populations. Red
supergiants in the Local Group have masses up to 25Msol and the minimum mass to
produce a Wolf-Rayet star in single star evolution (between solar and LMC
metallicity) is similarly 25-30 Msol. We term this discrepancy the "red
supergiant problem" and speculate that these stars could have core masses high
enough to form black holes and SNe which are too faint to have been detected.
Low luminosity SNe with low 56Ni production seem to arise from explosions of
low mass progenitors near the mass threshold for core-collapse. (abridged).Comment: 37 pages, 9 figs, accepted for publication in MNRA
Chemical Proteomic Analysis of Serine Hydrolase Activity in Niemann-Pick Type C Mouse Brain
The endocannabinoid system (ECS) is considered to be an endogenous protective system in various neurodegenerative diseases. Niemann-Pick type C (NPC) is a neurodegenerative disease in which the role of the ECS has not been studied yet. Most of the endocannabinoid enzymes are serine hydrolases, which can be studied using activity-based protein profiling (ABPP). Here, we report the serine hydrolase activity in brain proteomes of a NPC mouse model as measured by ABPP. Two ABPP methods are used: a gel-based method and a chemical proteomics method. The activities of the following endocannabinoid enzymes were quantified: diacylglycerol lipase (DAGL) α, α/β-hydrolase domain-containing protein 4, α/β-hydrolase domain-containing protein 6, α/β-hydrolase domain-containing protein 12, fatty acid amide hydrolase, and monoacylglycerol lipase. Using the gel-based method, two bands were observed for DAGL α. Only the upper band corresponding to this enzyme was significantly decreased in the NPC mouse model. Chemical proteomics showed that three lysosomal serine hydrolase activities (retinoid-inducible serine carboxypeptidase, cathepsin A, and palmitoyl-protein thioesterase 1) were increased in Niemann-Pick C1 protein knockout mouse brain compared to wild-type brain, whereas no difference in endocannabinoid hydrolase activity was observed. We conclude that these targets might be interesting therapeutic targets for future validation studies.Medical BiochemistryBio-organic SynthesisMolecular Physiolog
Weighing stars from birth to death: mass determination methods across the HRD
The mass of a star is the most fundamental parameter for its structure,
evolution, and final fate. It is particularly important for any kind of stellar
archaeology and characterization of exoplanets. There exists a variety of
methods in astronomy to estimate or determine it. In this review we present a
significant number of such methods, beginning with the most direct and
model-independent approach using detached eclipsing binaries. We then move to
more indirect and model-dependent methods, such as the quite commonly used
isochrone or stellar track fitting. The arrival of quantitative
asteroseismology has opened a completely new approach to determine stellar
masses and to complement and improve the accuracy of other methods. We include
methods for different evolutionary stages, from the pre-main sequence to
evolved (super)giants and final remnants. For all methods uncertainties and
restrictions will be discussed. We provide lists of altogether more than 200
benchmark stars with relative mass accuracies between for the
covered mass range of M\in [0.1,16]\,\msun, of which are stars burning
hydrogen in their core and the other covering all other evolved stages.
We close with a recommendation how to combine various methods to arrive at a
"mass-ladder" for stars.Comment: Invited review article for The Astronomy and Astrophysics Review. 146
pages, 16 figures, 11 tables. Accepted version by the Journal. It includes
summary figure of accuracy/precision of methods for mass ranges and summary
table for individual method
Weighing stars from birth to death : mass determination methods across the HRD
Funding: C.A., J.S.G.M., and M.G.P. received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 670519: MAMSIE). N.B. gratefully acknowledge financial support from the Royal Society (University Research Fellowships) and from the European Research Council (ERC-CoG-646928, Multi-Pop).The mass of a star is the most fundamental parameter for its structure, evolution, and final fate. It is particularly important for any kind of stellar archaeology and characterization of exoplanets. There exist a variety of methods in astronomy to estimate or determine it. In this review we present a significant number of such methods, beginning with the most direct and model-independent approach using detached eclipsing binaries. We then move to more indirect and model-dependent methods, such as the quite commonly used isochrone or stellar track fitting. The arrival of quantitative asteroseismology has opened a completely new approach to determine stellar masses and to complement and improve the accuracy of other methods. We include methods for different evolutionary stages, from the pre-main sequence to evolved (super)giants and final remnants. For all methods uncertainties and restrictions will be discussed. We provide lists of altogether more than 200 benchmark stars with relative mass accuracies between [0.3 ,2 ]% for the covered mass range of M ∈[0.1 ,16 ] M⊙ , 75 % of which are stars burning hydrogen in their core and the other 25 % covering all other evolved stages. We close with a recommendation how to combine various methods to arrive at a "mass-ladder" for stars.PostprintPeer reviewe
Increased Expression of Beta-Defensin 1 (DEFB1) in Chronic Obstructive Pulmonary Disease
On-going airway inflammation is characteristic for the pathophysiology of chronic obstructive pulmonary disease (COPD). However, the key factors determining the decrease in lung function, an important clinical parameter of COPD, are not clear. Genome-wide linkage analyses provide evidence for significant linkage to airway obstruction susceptibility loci on chromosome 8p23, the location of the human defensin gene cluster. Moreover, a genetic variation in the defensin beta 1 (DEFB1) gene was found to be associated with COPD. Therefore, we hypothesized that DEFB1 is differently regulated and expressed in human lungs during COPD progression. Gene expression of DEFB1 was assessed in bronchial epithelium and BAL fluid cells of healthy controls and patients with COPD and using bisulfite sequencing and ChIP analysis, the epigenetic control of DEFB1 mRNA expression was investigated. We can demonstrate that DEFB1 mRNA expression was significantly increased in bronchopulmonary specimen of patients with COPD (n = 34) vs. healthy controls (n = 10) (p<0.0001). Furthermore, a significant correlation could be detected between DEFB1 and functional parameters such as FEV1 (p = 0.0024) and the FEV1/VC ratio (p = 0.0005). Upregulation of DEFB1 mRNA was paralleled by changes in HDAC1-3, HDAC5 and HDAC8 mRNA expression. Whereas bisulfite sequencing revealed no differences in the methylation state of DEFB1 promoter between patients with COPD and controls, ChIP analysis showed that enhanced DEFB1 mRNA expression was associated with the establishment of an active histone code. Thus, expression of human DEFB1 is upregulated and related to the decrease in pulmonary function in patients with COPD
Clay content drives carbon stocks in soils under a plantation of Eucalyptus saligna Labill. in southern Brazil
Effects of a school-based health intervention program in marginalized communities of Port Elizabeth, South Africa (the KaziBantu Study): protocol for a randomized controlled trial
The burden of poverty-related infectious diseases remains high in low- and middle-income countries, while noncommunicable diseases (NCDs) are rapidly gaining importance. To address this dual disease burden, the KaziBantu project aims at improving and promoting health literacy as a means for a healthy and active lifestyle. The project implements a school-based health intervention package consisting of physical education, moving-to-music, and specific health and nutrition education lessons from the KaziKidz toolkit. It is complemented by the KaziHealth workplace health intervention program for teachers.; The aim of the KaziBantu project is to assess the effect of a school-based health intervention package on risk factors for NCDs, health behaviors, and psychosocial health in primary school children in disadvantaged communities in Port Elizabeth, South Africa. In addition, we aim to test a workplace health intervention for teachers.; A randomized controlled trial (RCT) will be conducted in 8 schools. Approximately 1000 grade 4 to grade 6 school children, aged 9 to 13 years, and approximately 60 teachers will be recruited during a baseline survey in early 2019. For school children, the study is designed as a 36-week, cluster RCT (KaziKidz intervention), whereas for teachers, a 24-week intervention phase (KaziHealth intervention) is planned. The intervention program consists of 3 main components; namely, (1) KaziKidz and KaziHealth teaching material, (2) workshops, and (3) teacher coaches. After randomization, 4 of the 8 schools will receive the education program, whereas the other schools will serve as the control group. Intervention schools will be further randomized to the different combinations of 2 additional intervention components: teacher workshops and teacher coaching.; This study builds on previous experience and will generate new evidence on health intervention responses to NCD risk factors in school settings as a decision tool for future controlled studies that will enable comparisons among marginalized communities between South African and other African settings.; The KaziKidz teaching material is a holistic educational and instructional tool designed for primary school teachers in low-resource settings, which is in line with South Africa's Curriculum and Assessment Policy Statement. The ready-to-use lessons and assessments within KaziKidz should facilitate the use and implementation of the teaching material. Furthermore, the KaziHealth interventions should empower teachers to take care of their health through knowledge gains regarding disease risk factors, physical activity, fitness, psychosocial health, and nutrition indicators. Teachers as role models will be able to promote better health behaviors and encourage a healthy and active lifestyle for children at school. We conjecture that improved health and well-being increase teachers' productivity with trickle-down effects on the children they teach and train.; International Standard Randomized Controlled Trial Number (ISRCTN): 18485542; http://www.isrctn.com/ISRCTN18485542.; DERR1-10.2196/14097
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