For this report, we examined the relationships between the conditions of being overweight and obese and mortality from all causes, heart disease, cardiovascular disease, and cancer.
We defined the ...categories of body weight according to level of body mass index,
BMI
=
wt
(
kg
)
ht
(
m
)
2
,
using classifications suggested by the National Institutes of Health and the World Health Organization. These classifications are as follows: “normal weight” is defined as BMI ≥ 18.5, but less than 25; “overweight” equals BMI ≥ 25, but less than 30; and “obese” individuals have BMIs ≥ 30. Our investigation is based on person-level data from 26 observational studies that include both genders, several racial and ethnic groups, and samples from the US and other countries. The database consists of 74 analytic cohorts, arranged according to natural strata including gender, race, and area of residence. It includes 388,622 individuals, with 60,374 deaths during follow-up. We use proportional hazards models to examine the relationships between the BMI categories and mortality, controlling for age and smoking status. We use random-effects models to assess summary relative risks associated with the overweight and obesity conditions across cohorts.
The relative risks among the heaviest individuals for overall death, death caused by coronary heart disease (CHD), and death caused by cardiovascular disease (CVD) are 1.22, 1.57, and 1.48, respectively, when compared with the those within the lowest BMI category. The summary relative risk among the heaviest participants for death from cancer is 1.07.
We document once again, excess mortality associated with obesity. Our results do, however, question whether the current classification of individuals as “overweight” is optimal in the sense, since there is little evidence of increased risk of mortality in this group.
The baryon cycle of galaxies is a dynamic process involving the intake, consumption and ejection of vast quantities of gas. In contrast, the conventional picture of satellite galaxies has them ...methodically turning a large gas reservoir into stars until this reservoir is forcibly removed due to external ram pressure. This picture needs revision. Our modern understanding of the baryon cycle suggests that in some regimes the simple interruption of the fresh gas supply may quench satellite galaxies long before stripping events occur, a process we call overconsumption. We compile measurements from the literature of observed satellite quenching times at a range of redshifts to determine if satellites are principally quenched through orbit-based gas stripping events – either direct stripping of the disc (ram pressure stripping) or the extended gas halo (strangulation) – or from internally driven star formation outflows via overconsumption. These time-scales show significant deviations from the evolution expected for gas stripping mechanisms and suggest that either ram pressure stripping is much more efficient at high redshift, or that secular outflows quench satellites before orbit-based stripping occurs. Given the strong redshift evolution of star formation rates, at high redshift even moderate outflow rates will lead to extremely short delay times with the expectation that high-redshift (z > 1.5) satellites will be quenched almost immediately following the cessation of cosmological inflow. Observations of high-redshift satellites give an indirect but sensitive measure of the outflow rate, with current measurements suggesting that outflows are no larger than 2.5 times the star formation rate for galaxies with a stellar mass of 1010.5 M⊙.
Exercise and GLUT4 Flores-Opazo, Marcelo; McGee, Sean L; Hargreaves, Mark
Exercise and sport sciences reviews,
07/2020, Volume:
48, Issue:
3
Journal Article
Peer reviewed
Open access
The glucose transporter GLUT4 is critical for skeletal muscle glucose uptake in response to insulin and muscle contraction/exercise. Exercise increases GLUT4 translocation to the sarcolemma and ...t-tubule and, over the longer term, total GLUT4 protein content. Here, we review key aspects of GLUT4 biology in relation to exercise, with a focus on exercise-induced GLUT4 translocation, postexercise metabolism and muscle insulin sensitivity, and exercise effects on GLUT4 expression.
Abstract
We introduce the Hydrangea simulations, a suite of 24 cosmological hydrodynamic zoom-in simulations of massive galaxy clusters (M
200c = 1014–1015.4 M⊙) with baryon particle masses of ∼106 ...M⊙. Designed to study the impact of the cluster environment on galaxy formation, they are a key part of the ‘Cluster–EAGLE’ project. They use a galaxy formation model developed for the EAGLE project, which has been shown to yield both realistic field galaxies and hot gas fractions of galaxy groups consistent with observations. The total stellar mass content of the simulated clusters agrees with observations, but central cluster galaxies are too massive, by up to 0.6 dex. Passive satellite fractions are higher than in the field, and at stellar masses M
star > 1010 M⊙, this environmental effect is quantitatively consistent with observations. The predicted satellite stellar mass function matches data from local cluster surveys. Normalized to total mass, there are fewer low-mass (M
star ≲ 1010 M⊙) galaxies within the virial radius of clusters than in the field, primarily due to star formation quenching. Conversely, the simulations predict an overabundance of massive galaxies in clusters compared to the field that persists to their far outskirts (>5 r
200c). This is caused by a significantly increased stellar mass fraction of (sub-)haloes in the cluster environment, by up to ∼0.3 dex even well beyond r
200c. Haloes near clusters are also more concentrated than equally massive field haloes, but these two effects are largely uncorrelated.
ABSTRACT We present a study of the spatial distribution and kinematics of star-forming galaxies in 30 massive clusters at 0.15 < z < 0.30, combining wide-field Spitzer 24 m and GALEX near-ultraviolet ...imaging with highly complete spectroscopy of cluster members. The fraction (fSF) of star-forming cluster galaxies rises steadily with cluster-centric radius, increasing fivefold by 2r200, but remains well below field values even at 3r200. This suppression of star formation at large radii cannot be reproduced by models in which star formation is quenched in infalling field galaxies only once they pass within r200 of the cluster, but is consistent with some of them being first pre-processed within galaxy groups. Despite the increasing fSF-radius trend, the surface density of star-forming galaxies actually declines steadily with radius, falling ∼15× from the core to 2r200. This requires star formation to survive within recently accreted spirals for 2-3 Gyr to build up the apparent over-density of star-forming galaxies within clusters. The velocity dispersion profile of the star-forming galaxy population shows a sharp peak of 1.44 at 0.3r500, and is 10%-35% higher than that of the inactive cluster members at all cluster-centric radii, while their velocity distribution shows a flat, top-hat profile within r500. All of these results are consistent with star-forming cluster galaxies being an infalling population, but one that must also survive ∼0.5-2 Gyr beyond passing within r200. By comparing the observed distribution of star-forming galaxies in the stacked caustic diagram with predictions from the Millennium simulation, we obtain a best-fit model in which star formation rates decline exponentially on quenching timescales of 1.73 0.25 Gyr upon accretion into the cluster.
Abstract
We report direct evidence of pre-processing of the galaxies residing in galaxy groups falling into galaxy clusters drawn from the Local Cluster Substructure Survey (LoCuSS). 34 groups have ...been identified via their X-ray emission in the infall regions of 23 massive (〈M200〉 = 1015 M⊙) clusters at 0.15 < z < 0.3. Highly complete spectroscopic coverage combined with 24 μm imaging from Spitzer allows us to make a consistent and robust selection of cluster and group members including star-forming galaxies down to a stellar mass limit of M⋆ = 2 × 1010 M⊙. The fraction fSF of star-forming galaxies in infalling groups is lower and with a flatter trend with respect to clustercentric radius when compared to the rest of the cluster galaxy population. At R ≈ 1.3 r200, the fraction of star-forming galaxies in infalling groups is half that in the cluster galaxy population. This is direct evidence that star-formation quenching is effective in galaxies already prior to them settling in the cluster potential, and that groups are favourable locations for this process.
This paper presents a spatially resolved kinematic study of the jellyfish galaxy JO201, one of the most spectacular cases of ram-pressure stripping (RPS) in the GAs Stripping Phenomena in galaxies ...with MUSE (GASP) survey. By studying the environment of JO201, we find that it is moving through the dense intracluster medium of Abell 85 at supersonic speeds along our line of sight, and that it is likely accompanied by a small group of galaxies. Given the density of the intracluster medium and the galaxy's mass, projected position, and velocity within the cluster, we estimate that JO201 must so far have lost ∼50% of its gas during infall via RPS. The MUSE data indeed reveal a smooth stellar disk accompanied by large projected tails of ionized ( ) gas, composed of kinematically cold (velocity dispersion <40 km s−1) star-forming knots and very warm (>100 km s−1) diffuse emission, that extend out to at least from the galaxy center. The ionized -emitting gas in the disk rotates with the stars out to ∼6 kpc; but, in the disk outskirts, it becomes increasingly redshifted with respect to the (undisturbed) stellar disk. The observed disturbances are consistent with the presence of gas trailing behind the stellar component resulting from intense face-on RPS along the line of sight. Our kinematic analysis is consistent with the estimated fraction of lost gas and reveals that stripping of the disk happens outside-in, causing shock heating and gas compression in the stripped tails.
Dichloroacetate (DCA), through the inhibition of aerobic glycolysis (the 'Warburg effect') and promotion of pyruvate oxidation, induces growth reduction in many tumours and is now undergoing several ...clinical trials. If aerobic glycolysis is active in multiple myeloma (MM) cells, it can be potentially targeted by DCA to induce myeloma growth inhibition.
Representative multiple myeloma cell lines and a myeloma-bearing mice were treated with DCA, alone and in combination with bortezomib.
We found that aerobic glycolysis occurs in approximately half of MM cell lines examined, producing on average 1.86-fold more lactate than phorbol myristate acetate stimulated-peripheral blood mononuclear cells and is associated with low-oxidative capacity. Lower doses of DCA (5-10 mM) suppressed aerobic glycolysis and improved cellular respiration that was associated with activation of the pyruvate dehydrogenase complex. Higher doses of DCA (10-25 mM) induced superoxide production, apoptosis, suppressed proliferation with a G0/1 and G2M phase arrest in MM cell lines. In addition, DCA increased MM cell line sensitivity to bortezomib, and combinatorial treatment of both agents improved the survival of myeloma-bearing mice.
Myeloma cells display aerobic glycolysis and DCA may complement clinically used MM therapies to inhibit disease progression.
Skeletal muscle phenotype plays a critical role in human performance and health, and skeletal muscle oxidative capacity is a key determinant of exercise tolerance. More recently, defective muscle ...oxidative metabolism has been implicated in a number of conditions associated with the metabolic syndrome, cardiovascular disease and muscle-wasting disorders. AMPK (AMP-activated protein kinase) is a critical regulator of cellular and organismal energy balance. AMPK has also emerged as a key regulator of skeletal muscle oxidative function, including metabolic enzyme expression, mitochondrial biogenesis and angiogenesis. AMPK mediates these processes primarily through alterations in gene expression. The present review examines the role of AMPK in skeletal muscle transcription and provides an overview of the known transcriptional substrates mediating the effects of AMPK on skeletal muscle phenotype.
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