815 research outputs found
Effect of cut-out on modal properties of edge cracked temperature-dependent functionally graded plates
Modal analysis is employed to analyze the vibration of temperature-dependent of Functionally Graded Plates (FGP) under a thermal environment in order to determine the natural frequencies and mode shapes. Theoretical formulation of various materialsā properties is done using the rule of mixtures. The natural frequencies and mode shapes of simply supported and clamped square plates are investigated as a function of crack, cutout, crack and cutout and temperature dependent properties. The Ansys program is employed for the purpose of analyzing the natural frequency and mode shape of a plate. Non-dimensional results are compared for temperature-dependent and temperature-independent FGP and subsequently validated according to known results obtained from the literature. Numerical results indicate the effect of crack, cutout, gradient index and temperature fields on the vibration characteristics and mode shapes. This study proves that natural frequency decreases with increasing gradient index (n) increasing the temperature and simultaneous presence of crack-cutout. In addition, clamped plates have a higher frequency than simply supported plates in all cases. Increasing temperatures lead to a maximum decrease in frequency at clamped FGP
Long-term exposure to air-pollution and COVID-19 mortality in England: a hierarchical spatial analysis
Recent studies suggested a link between long-term exposure to air-pollution and COVID-19 mortality. However, due to their ecological design based on large spatial units, they neglect the strong localised air-pollution patterns, and potentially lead to inadequate confounding adjustment. We investigated the effect of long-term exposure to NO2 and PM2.5 on COVID-19 mortality in England using high geographical resolution. In this nationwide cross-sectional study in England, we included 38,573 COVID-19 deaths up to June 30, 2020 at the Lower Layer Super Output Area level (n = 32,844 small areas). We retrieved averaged NO2 and PM2.5 concentration during 2014ā2018 from the Pollution Climate Mapping. We used Bayesian hierarchical models to quantify the effect of air-pollution while adjusting for a series of confounding and spatial autocorrelation. We find a 0.5% (95% credible interval: ā0.2%, 1.2%) and 1.4% (95% CrI: ā2.1%, 5.1%) increase in COVID-19 mortality risk for every 1 Ī¼g/m3 increase in NO2 and PM2.5 respectively, after adjusting for confounding and spatial autocorrelation. This corresponds to a posterior probability of a positive effect equal to 0.93 and 0.78 respectively. The spatial relative risk at LSOA level revealed strong patterns, similar for the different pollutants. This potentially captures the spread of the disease during the first wave of the epidemic. Our study provides some evidence of an effect of long-term NO2 exposure on COVID-19 mortality, while the effect of PM2.5 remains more uncertain
Numerical Solution of Time-Fractional Order Telegraph Equation by Bernstein Polynomials Operational Matrices
We present a new method to solve time-fractional order telegraph equation (TFOTE) by using Bernstein polynomials. By implementation of Bernstein polynomials operational matrices of fractional differential on TFOTE, we reduce the original problem to a linear system of algebraic equations. Also, we prove the convergence analysis. In order to show the efficiency of the proposed method, we present two numerical examples
Eight Americas: Investigating Mortality Disparities across Races, Counties, and Race-Counties in the United States
BACKGROUND: The gap between the highest and lowest life expectancies for race-county combinations in the United States is over 35 y. We divided the race-county combinations of the US population into eight distinct groups, referred to as the āeight Americas,ā to explore the causes of the disparities that can inform specific public health intervention policies and programs. METHODS AND FINDINGS: The eight Americas were defined based on race, location of the county of residence, population density, race-specific county-level per capita income, and cumulative homicide rate. Data sources for population and mortality figures were the Bureau of the Census and the National Center for Health Statistics. We estimated life expectancy, the risk of mortality from specific diseases, health insurance, and health-care utilization for the eight Americas. The life expectancy gap between the 3.4 million high-risk urban black males and the 5.6 million Asian females was 20.7 y in 2001. Within the sexes, the life expectancy gap between the best-off and the worst-off groups was 15.4 y for males (Asians versus high-risk urban blacks) and 12.8 y for females (Asians versus low-income southern rural blacks). Mortality disparities among the eight Americas were largest for young (15ā44 y) and middle-aged (45ā59 y) adults, especially for men. The disparities were caused primarily by a number of chronic diseases and injuries with well-established risk factors. Between 1982 and 2001, the ordering of life expectancy among the eight Americas and the absolute difference between the advantaged and disadvantaged groups remained largely unchanged. Self-reported health plan coverage was lowest for western Native Americans and low-income southern rural blacks. Crude self-reported health-care utilization, however, was slightly higher for the more disadvantaged populations. CONCLUSIONS: Disparities in mortality across the eight Americas, each consisting of millions or tens of millions of Americans, are enormous by all international standards. The observed disparities in life expectancy cannot be explained by race, income, or basic health-care access and utilization alone. Because policies aimed at reducing fundamental socioeconomic inequalities are currently practically absent in the US, health disparities will have to be at least partly addressed through public health strategies that reduce risk factors for chronic diseases and injuries
Chemical Characterization and Source Apportionment of Household Fine Particulate Matter in Rural, Peri-urban, and Urban West Africa
Household air pollution in sub-Saharan Africa and other developing regions is an important cause of disease burden. Little is known about the chemical composition and sources of household air pollution in sub-Saharan Africa, and how they differ between rural and urban homes. We analyzed the chemical composition and sources of fine particles (PM2.5) in household cooking areas of multiple neighborhoods in Accra, Ghana, and in peri-urban (Banjul) and rural (Basse) areas in The Gambia. In Accra, biomass burning accounted for 39ā62% of total PM2.5 mass in the cooking area in different neighborhoods; the absolute contributions were 10ā45 Ī¼g/m3. Road dust and vehicle emissions comprised 12ā33% of PM2.5 mass. Solid waste burning was also a significant contributor to household PM2.5 in a low-income neighborhood but not for those living in better-off areas. In Banjul and Basse, biomass burning was the single dominant source of cooking-area PM2.5, accounting for 74ā87% of its total mass; the relative and absolute contributions of biomass smoke to PM2.5 mass were larger in households that used firewood than in those using charcoal, reaching as high as 463 Ī¼g/m3 in Basse homes that used firewood for cooking. Our findings demonstrate the need for policies that enhance access to cleaner fuels in both rural and urban areas, and for controlling traffic emissions in cities in sub-Saharan Africa
Self-reported use of tobacco products in nine rural INDEPTH Health and Demographic Surveillance Systems in Asia
BACKGROUND: Tobacco use is the most preventable cause of premature death and disability. Even though tobacco use is common in many Asian countries, reliable and comparable data on the burden imposed by tobacco use in this region are sparse, and surveillance systems to track trends are in their infancy. OBJECTIVE: To assess and compare the prevalence of tobacco use and its associated factors in nine selected rural sites in five Asian countries. METHODS: Tobacco use among 9,208 men and 9,221 women aged 25-64 years in nine Health and Demographic Surveillance System (HDSS) sites in five Asian countries of the INDEPTH Network were examined in 2005 as part of a broader survey of the major chronic non-communicable disease risk factors. All sites used a standardised protocol based on the WHO STEPS approach to risk factor surveillance; expanded questions of local relevance, including chewing tobacco, were also included. Multivariable logistic regression was used to assess demographic factors associated with tobacco use. RESULTS: Tobacco use, whether smoked or chewed, was common across all sites with some notable variations. More than 50% of men smoked daily; this applied to almost all age groups. Few women smoked daily in any of the sites. However, women were more likely to chew tobacco than men in all sites except Vadu in India. Tobacco use in men began in late adolescence in most of the sites and the number of cigarettes smoked daily ranged from three to 15. Use of both forms of tobacco, smoked and chewed, was associated with age, gender and education. Men were more likely to smoke compared to women, smoking increased with age in the four sites in Bangladesh but not in other sites and with low level of education in all the sites. CONCLUSION: The prevalence of tobacco use, regardless of the type of tobacco, was high among men in all of these rural populations with tobacco use started during adolescence in all HDSS sites. Innovative communication strategies for behaviour change targeting adolescents in schools and adult men and women at work or at home, may create a mass awareness about adverse health consequences of tobacco smoking or chewing tobacco. Such efforts, to be effective, however, need to be supported by strong legislation and leadership. Only four of the five countries involved in this multi-site study have ratified the Framework Convention on Tobacco Control, and even where it has been ratified, implementation is uneven.Supplement:Ā 1</p
Endocrine profile of the kisspeptin receptor agonist MVT-602 in healthy premenopausal women with and without ovarian stimulation: results from two randomized, placebo-controlled clinical trials
Kisspeptin is an essential regulator of hypothalamic gonadotropin-releasing hormone release and is required for physiological ovulation. Native kisspeptin-54 (KP54) can induce oocyte maturation during in vitro fertilization treatment, including in women at high risk of ovarian hyperstimulation syndrome. MVT-602 is a potent kisspeptin receptor agonist with prospective utility to treat anovulatory disorders by triggering oocyte maturation and ovulation during medically assisted reproduction (MAR). Currently, the endocrine profile of MVT-602 during ovarian stimulation is unreported. Objective To determine the endocrine profile of MVT-602 in the follicular phase of healthy premenopausal women (Phase-1 trial), and after minimal ovarian stimulation to more closely reflect the endocrine milieu encountered during MAR (Phase-2a trial). Design Two randomized, placebo-controlled, parallel group, dose-finding trials. Setting Clinical trials unit, Netherlands. Participants Healthy women aged 18-35 years, either without (Phase-1; n=24), or with ovarian stimulation (Phase-2a; n=75). Interventions Phase-1: Single subcutaneous dose of MVT-602 (0.3, 1.0, or 3.0 Ī¼g) or placebo, (n=6 per dose). Phase-2a: Single subcutaneous dose of MVT-602 (0.1, 0.3, 1.0, or 3.0 Ī¼g; n=16-17 per dose), triptorelin 0.2 mg (n=5; active comparator), or placebo (n=5). Main Objectives and Outcome Measures Phase-1: Safety/tolerability; pharmacokinetics; pharmacodynamics (LH and other reproductive hormones). Phase-2a: Safety/tolerability; pharmacokinetics; pharmacodynamics (LH and other reproductive hormones); time to ovulation assessed by transvaginal ultrasound. Results In both trials, MVT-602 was safe and well-tolerated across the entire dose-range. It was rapidly absorbed and eliminated, with a mean elimination half-life of 1.3-2.2 hours. In the Phase-2a trial, LH concentrations increased dose-dependently; mean maximum change from baseline of 82.4 IU/L at 24.8 hours was observed after administration of 3Ī¼g MVT-602 and remained above 15 IU/L for 33 hours. Time to ovulation following drug administration was 3.3-3.9 days (MVT-602), 3.4 days (triptorelin), and 5.5 days (placebo). Ovulation occurred within 5 days of administration in 100% (3 Ī¼g), 88% (1Ī¼g), 82% (0.3Ī¼g), and 75% (0.1Ī¼g), of women after MVT-602, 100% after triptorelin, and 60% after placebo. Conclusions MVT-602 induces LH concentrations of similar amplitude and duration as the physiological mid-cycle LH surge with potential utility for induction of oocyte maturation and ovulation during MAR
The present and future burden of urinary bladder cancer in the world
Urinary bladder cancer (UBC) is a common disease worldwide. At any point in time 2.7Ā million people have a history of UBC. The incidence of UBC varies over the world with highest rates in developed communities. But the burden of UBC will increase in less developed areas of the world. These changes can be attributed to global changes in exposure to risk factors for UBC and growth and aging of the world population
Rethinking the āDiseases of Affluenceā Paradigm: Global Patterns of Nutritional Risks in Relation to Economic Development
BACKGROUND: Cardiovascular diseases and their nutritional risk factorsāincluding overweight and obesity, elevated blood pressure, and cholesterolāare among the leading causes of global mortality and morbidity, and have been predicted to rise with economic development. METHODS AND FINDINGS: We examined age-standardized mean population levels of body mass index (BMI), systolic blood pressure, and total cholesterol in relation to national income, food share of household expenditure, and urbanization in a cross-country analysis. Data were from a total of over 100 countries and were obtained from systematic reviews of published literature, and from national and international health agencies. BMI and cholesterol increased rapidly in relation to national income, then flattened, and eventually declined. BMI increased most rapidly until an income of about I12,500 for females and I8,000 and I$18,000, respectively). There was an inverse relationship between BMI/cholesterol and the food share of household expenditure, and a positive relationship with proportion of population in urban areas. Mean population blood pressure was not correlated or only weakly correlated with the economic factors considered, or with cholesterol and BMI. CONCLUSIONS: When considered together with evidence on shifts in incomeārisk relationships within developed countries, the results indicate that cardiovascular disease risks are expected to systematically shift to low-income and middle-income countries and, together with the persistent burden of infectious diseases, further increase global health inequalities. Preventing obesity should be a priority from early stages of economic development, accompanied by population-level and personal interventions for blood pressure and cholesterol
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