130 research outputs found
The solubility of helium in leadâlithium eutectic alloy
The helium production rates in liquid metals (Pb-Li eutectic alloy, LLE and others) Blanket Breeders (BB) are nearly mol-to-mol linked to tritium and intimately associated with the compulsory requirement of high tritium self-sufficiency of next fusion reactors. When LLE is oversaturated and the helium solubility limit is exceeded, helium atoms can nucleate in the form of bubbles. The presence of helium bubbles within LLE channels could have severe impact on the diverse BB designs, in particular on tritium transport permeation and its recovery. Even though He is an inert gas assumed to be insoluble, the helium Henryâs constant (KH) in a liquid metal is not zero. The very low KH and difficulties to measure it has historically driven to the absence of basic data. A semi-empirical correlation is proposed providing the helium solubility (i.e.: the helium Henryâs constant) based on Kumarâs cohesion model using the available thermo-physical experimental solubility data for lithium, sodium, potassium, mercury. The proposed expression for eutectic leadâlithium is: being KH the Henryâs constant; T [K], R [8.314 10-3 kJ mol-1 K-1] and dk the Kumarâs cohesive parameter. From a dk justified value of 18.2 MPa1/2 in LLE the values for KH range from 1.14·10-17 to 1.35·10 -15 at.fr.Pa-1 for temperatures between 350 and 870C. The helium solubility should integrate the leadâlithium eutectic nuclear material database for fusion systems design.Peer ReviewedPostprint (published version
Global, regional, and national burden of other musculoskeletal disorders, 1990â2020, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021
Background
Musculoskeletal disorders include more than 150 different conditions affecting joints, muscles, bones, ligaments, tendons, and the spine. To capture all health loss from death and disability due to musculoskeletal disorders, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) includes a residual musculoskeletal category for conditions other than osteoarthritis, rheumatoid arthritis, gout, low back pain, and neck pain. This category is called other musculoskeletal disorders and includes, for example, systemic lupus erythematosus and spondylopathies. We provide updated estimates of the prevalence, mortality, and disability attributable to other musculoskeletal disorders and forecasted prevalence to 2050.
Methods
Prevalence of other musculoskeletal disorders was estimated in 204 countries and territories from 1990 to 2020 using data from 68 sources across 23 countries from which subtraction of cases of rheumatoid arthritis, osteoarthritis, low back pain, neck pain, and gout from the total number of cases of musculoskeletal disorders was possible. Data were analysed with Bayesian meta-regression models to estimate prevalence by year, age, sex, and location. Years lived with disability (YLDs) were estimated from prevalence and disability weights. Mortality attributed to other musculoskeletal disorders was estimated using vital registration data. Prevalence was forecast to 2050 by regressing prevalence estimates from 1990 to 2020 with Socio-demographic Index as a predictor, then multiplying by population forecasts.
Findings
Globally, 494 million (95% uncertainty interval 431â564) people had other musculoskeletal disorders in 2020, an increase of 123·4% (116·9â129·3) in total cases from 221 million (192â253) in 1990. Cases of other musculoskeletal disorders are projected to increase by 115% (107â124) from 2020 to 2050, to an estimated 1060 million (95% UI 964â1170) prevalent cases in 2050; most regions were projected to have at least a 50% increase in cases between 2020 and 2050. The global age-standardised prevalence of other musculoskeletal disorders was 47·4% (44·9â49·4) higher in females than in males and increased with age to a peak at 65â69 years in male and female sexes. In 2020, other musculoskeletal disorders was the sixth ranked cause of YLDs globally (42·7 million [29·4â60·0]) and was associated with 83â100 deaths (73â600â91â600).
Interpretation
Other musculoskeletal disorders were responsible for a large number of global YLDs in 2020. Until individual conditions and risk factors are more explicitly quantified, policy responses to this burden remain a challenge. Temporal trends and geographical differences in estimates of non-fatal disease burden should not be overinterpreted as they are based on sparse, low-quality data.publishedVersio
Glucocorticoids promote structural and functional maturation of foetal cardiomyocytes: a role for PGC-1α
Glucocorticoid levels rise dramatically in late gestation to mature foetal organs in readiness for postnatal life. Immature heart function may compromise survival. Cardiomyocyte glucocorticoid receptor (GR) is required for the structural and functional maturation of the foetal heart in vivo, yet the molecular mechanisms are largely unknown. Here we asked if GR activation in foetal cardiomyocytes in vitro elicits similar maturational changes. We show that physiologically relevant glucocorticoid levels improve contractility of primary-mouse-foetal cardiomyocytes, promote Z-disc assembly and the appearance of mature myofibrils, and increase mitochondrial activity. Genes induced in vitro mimic those induced in vivo and include PGC-1α, a critical regulator of cardiac mitochondrial capacity. SiRNA-mediated abrogation of the glucocorticoid induction of PGC-1α in vitro abolished the effect of glucocorticoid on myofibril structure and mitochondrial oxygen consumption. Using RNA sequencing we identified a number of transcriptional regulators, including PGC-1α, induced as primary targets of GR in foetal cardiomyocytes. These data demonstrate that PGC-1α is a key mediator of glucocorticoid-induced maturation of foetal cardiomyocyte structure and identify other candidate transcriptional regulators that may play critical roles in the transition of the foetal to neonatal heart
Vertebrate Vitellogenin Gene Duplication in Relation to the â3R Hypothesisâ: Correlation to the Pelagic Egg and the Oceanic Radiation of Teleosts
The spiny ray-finned teleost fishes (Acanthomorpha) are the most successful group of vertebrates in terms of species diversity. Their meteoric radiation and speciation in the oceans during the late Cretaceous and Eocene epoch is unprecedented in vertebrate history, occurring in one third of the time for similar diversity to appear in the birds and mammals. The success of marine teleosts is even more remarkable considering their long freshwater ancestry, since it implies solving major physiological challenges when freely broadcasting their eggs in the hyper-osmotic conditions of seawater. Most extant marine teleosts spawn highly hydrated pelagic eggs, due to differential proteolysis of vitellogenin (Vtg)-derived yolk proteins. The maturational degradation of Vtg involves depolymerization of mainly the lipovitellin heavy chain (LvH) of one form of Vtg to generate a large pool of free amino acids (FAA 150â200 mM). This organic osmolyte pool drives hydration of the ooctye while still protected within the maternal ovary. In the present contribution, we have used Bayesian analysis to examine the evolution of vertebrate Vtg genes in relation to the â3R hypothesisâ of whole genome duplication (WGD) and the functional end points of LvH degradation during oocyte maturation. We find that teleost Vtgs have experienced a post-R3 lineage-specific gene duplication to form paralogous clusters that correlate to the pelagic and benthic character of the eggs. Neo-functionalization allowed one paralogue to be proteolyzed to FAA driving hydration of the maturing oocytes, which pre-adapts them to the marine environment and causes them to float. The timing of these events matches the appearance of the Acanthomorpha in the fossil record. We discuss the significance of these adaptations in relation to ancestral physiological features, and propose that the neo-functionalization of duplicated Vtg genes was a key event in the evolution and success of the teleosts in the oceanic environment
The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019
Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe
Going âsocialâ to access experimental and potentially life-saving treatment: an assessment of the policy and online patient advocacy environment for expanded access
Evacetrapib and Cardiovascular Outcomes in High-Risk Vascular Disease
BACKGROUND:
The cholesteryl ester transfer protein inhibitor evacetrapib substantially raises the high-density lipoprotein (HDL) cholesterol level, reduces the low-density lipoprotein (LDL) cholesterol level, and enhances cellular cholesterol efflux capacity. We sought to determine the effect of evacetrapib on major adverse cardiovascular outcomes in patients with high-risk vascular disease.
METHODS:
In a multicenter, randomized, double-blind, placebo-controlled phase 3 trial, we enrolled 12,092 patients who had at least one of the following conditions: an acute coronary syndrome within the previous 30 to 365 days, cerebrovascular atherosclerotic disease, peripheral vascular arterial disease, or diabetes mellitus with coronary artery disease. Patients were randomly assigned to receive either evacetrapib at a dose of 130 mg or matching placebo, administered daily, in addition to standard medical therapy. The primary efficacy end point was the first occurrence of any component of the composite of death from cardiovascular causes, myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina.
RESULTS:
At 3 months, a 31.1% decrease in the mean LDL cholesterol level was observed with evacetrapib versus a 6.0% increase with placebo, and a 133.2% increase in the mean HDL cholesterol level was seen with evacetrapib versus a 1.6% increase with placebo. After 1363 of the planned 1670 primary end-point events had occurred, the data and safety monitoring board recommended that the trial be terminated early because of a lack of efficacy. After a median of 26 months of evacetrapib or placebo, a primary end-point event occurred in 12.9% of the patients in the evacetrapib group and in 12.8% of those in the placebo group (hazard ratio, 1.01; 95% confidence interval, 0.91 to 1.11; P=0.91).
CONCLUSIONS:
Although the cholesteryl ester transfer protein inhibitor evacetrapib had favorable effects on established lipid biomarkers, treatment with evacetrapib did not result in a lower rate of cardiovascular events than placebo among patients with high-risk vascular disease. (Funded by Eli Lilly; ACCELERATE ClinicalTrials.gov number, NCT01687998 .)
The Equivalency of Theoretical and Monte Carlo Approaches in Neutron Transport: the case of simplified slowing-down
For purposes of engineering education, computer experiments or simulations are powerful tools to demonstrate and emphasize physical concepts instead of relying on complex and ambiguous mathematics. The main advantage of MC methods in the discipline of neutron transport that facilitates teaching is the simplicity of the Random Walk concept; thus, allowing the use of trivial arguments and visualization of problems. Simple applications of MC methods for neutron slowing-down and diffusion through elastic scattering and absorption in a homogeneous media from a monochromatic beam were illustrated separately by Peralta (2002 Eur. J. Phys. 23 307) and Capizzo et al. (2005 Eur. J. Phys. 26 85). In this contribution, the two applications are merged to serve as a course project, a few corrections to the original manuscripts are provided and important theoretical aspects are highlighted. In essence, conservation equations of neutron-nucleus collisions are solved using frame-of-reference transformation and analytical formula independently to demonstrate the equivalency using the case of slowing-down in a mixture. 1-D/3-D transformation of coordinates are reviewed and deployed to eliminate any bias in the MC simulation.Peer ReviewedPostprint (published version
Atomistic simulations and theoretical predictions of helium nucleation in liquid Pb-Li eutectic alloy
Liquid Lead-Lithium Eutectic (LLE) alloy is a promising candidate coolant and/or breeder to attain tritium self-sufficiency in the EU DEMO breeding blanket design. Liquid metals are characterized with excellent heat-transport properties, and a wide range of densities, melting points and low viscosities. More than 20 years ago, a potential helium nucleation issue in LLE was raised based on experimental observations, since helium is produced in a one-to-one mole ratio with tritium through nuclear breeding reactions of Li isotopes. Theoretical and numerical modelling investigations remained inconclusive due to the complexity of the system, i.e., multi-component system of liquid metal and a noble gas with extremely low solubility, thus challenging the validity of the relevant theories. In this study, ab initio and classical Molecular Dynamics methods are used to investigate the helium bubble formation in LLE. An Embedded Atom Method potential is developed to model liquid Li with enhanced performance and transferability to reproduced LLE characteristics. The nucleation phenomenon of helium is investigated by implementing the Mean First-Passage Time atomistic technique, and nucleation curves are produced for a variety of thermodynamic states. It is found that helium is in the regime of kinetic spinodal, which suggests that nucleation of small clusters is imminent, and bubble growth to a macroscopic-size is only a function of time.Peer ReviewedPostprint (published version
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