Numerical studies of the conventional impact damper with discrete frequency optimization and uncertainty considerations

AbstractThis paper presents the performance of a single horizontal conventional Impact Damper (ID) in both wide range frequency and resonance excitations. The effects of the coefficient of restitution, e, mass ratio, μ, and clearance, d, on the performance of ID are investigated. The optimal parameters are numerically found by discretely varying the clearance and excitation frequency. The performance of optimal ID is discussed, with respect to different parameters, in both resonance and off-resonance modes. In addition, it is shown how the efficiency of the optimal conventional ID is deteriorated as a result of mistuning in the amplitude and frequency of excitation. This is estimated by suggesting a new criterion of post processing data. It is shown that an ID designed to resist high amplitude excitation is able to perform well at lower amplitude. However, the opposite trend can significantly deteriorate the efficiency of optimal ID. In regard to excitation frequency, the ID, optimized with respect to a wide range of frequency, is less sensitive to frequency mistuning. Finally, the vulnerability of the optimized ID versus uncertainties in structural parameters is clearly determined and it is illustrated that less robustness occurs when the performance of the controller is more efficient

An approximation algorithm for the solution of the nonlinear Lane-Emden type equations arising in astrophysics using Hermite functions collocation method

In this paper we propose a collocation method for solving some well-known classes of Lane-Emden type equations which are nonlinear ordinary differential equations on the semi-infinite domain. They are categorized as singular initial value problems. The proposed approach is based on a Hermite function collocation (HFC) method. To illustrate the reliability of the method, some special cases of the equations are solved as test examples. The new method reduces the solution of a problem to the solution of a system of algebraic equations. Hermite functions have prefect properties that make them useful to achieve this goal. We compare the present work with some well-known results and show that the new method is efficient and applicable.Comment: 34 pages, 13 figures, Published in "Computer Physics Communications

Effect of general health status on chronicity of low back pain in industrial workers

Recognizing patients at a higher risk of developing chronic low back pain (LBP) is important in industrial medicine. This study aimed to assess the power and quality of General Health Questionnaire (GHQ) for prediction of the odds of chronicity of acute LBP. This study was conducted on industrial workers. All subjects with acute LBP who met the inclusion criteria were enrolled. Demographic characteristics, occupational, physical, and mental parameters and the general health status of subjects were evaluated; they were followed up for developing chronic LBP for one year. Cigarette smoking, high body mass index, job stress, physical load and high GHQ scores were found to be the risk factors for the progression of acute LBP to chronic LBP (P0.05). High GHQ score can be a risk factor for progression of acute LBP to chronic LBP. The GHQ in combination with the Job Content Questionnaire can be used as a quick and simple screening tool for detection of subjects at high risk of chronic LBP when evaluating acute LBP in an occupational setting. © 2016 Tehran University of Medical Sciences. All rights reserved.

Characteristics, outcomes, and predictors of in-hospital mortality in patients hospitalized with acute systolic heart failure (HFrEF): Two-center registry of acute heart failure from Iran

Background: Acute Heart Failure (AHF) is a common cause of hospitalization in many countries. Rehospitalization due to AHF is also a very important economic issue for health services. Registries for AHF have been made in many countries to characterize such patients, which have provided great information about these patients for better care. To date, there is insufficient information about these patients in Iran and their rehospitalization and short-and long-term follow-up is unclear. Objectives: This study aims to describe the results of a small registry of AHF (HFrEF) patients in Iran and their short-term follow-up. Patients and Methods: This study aimed to describe the earliest results of the AHF registry, which was started from September 2015 in two hospitals (Afshar Heart Center in Yazd and Rajaie Heart Center in Tehran). All patients with diagnosis of AHF and HFrEF were enrolled into this registry. During six months, 352 patients with diagnosis of AHF and HFrEF were entered into this registry. The patients� demographic, clinical, and Para clinical data were collected during hospitalization and they were followed up for all-cause mortality and hospitalization for three months. Patients suffering from heart failure with preserved ejection fraction were excluded because of their small number and incomplete data. Results: The mean age of the patients was 55 ± 16 years and 76 were male. Besides, 77 of the patients had acute decompensation of chronic heart failure and 17 had new-onset AHF. Etiology of heart failure was ischemic heart disease in 52 of the patients. Additionally, the mean left ventricular ejection fraction was 20. Moreover, length of hospital stay was 10.5±10 days and in-hospital mortality rate was 9.7. Conclusions: This small and limited registry of patients with AHF (HFrEF) in Iran delineated these patients� characteristics with some discrepancies and similarities with western registries. Thus, a larger nationwide registry is needed for further clarification of the issue. © 2018, Iranian Cardiovascular Research Journal. All rights reserved

Characteristics, outcomes, and predictors of in-hospital mortality in patients hospitalized with acute systolic heart failure (HFrEF): Two-center registry of acute heart failure from Iran

Background: Acute Heart Failure (AHF) is a common cause of hospitalization in many countries. Rehospitalization due to AHF is also a very important economic issue for health services. Registries for AHF have been made in many countries to characterize such patients, which have provided great information about these patients for better care. To date, there is insufficient information about these patients in Iran and their rehospitalization and short-and long-term follow-up is unclear. Objectives: This study aims to describe the results of a small registry of AHF (HFrEF) patients in Iran and their short-term follow-up. Patients and Methods: This study aimed to describe the earliest results of the AHF registry, which was started from September 2015 in two hospitals (Afshar Heart Center in Yazd and Rajaie Heart Center in Tehran). All patients with diagnosis of AHF and HFrEF were enrolled into this registry. During six months, 352 patients with diagnosis of AHF and HFrEF were entered into this registry. The patients� demographic, clinical, and Para clinical data were collected during hospitalization and they were followed up for all-cause mortality and hospitalization for three months. Patients suffering from heart failure with preserved ejection fraction were excluded because of their small number and incomplete data. Results: The mean age of the patients was 55 ± 16 years and 76 were male. Besides, 77 of the patients had acute decompensation of chronic heart failure and 17 had new-onset AHF. Etiology of heart failure was ischemic heart disease in 52 of the patients. Additionally, the mean left ventricular ejection fraction was 20. Moreover, length of hospital stay was 10.5±10 days and in-hospital mortality rate was 9.7. Conclusions: This small and limited registry of patients with AHF (HFrEF) in Iran delineated these patients� characteristics with some discrepancies and similarities with western registries. Thus, a larger nationwide registry is needed for further clarification of the issue. © 2018, Iranian Cardiovascular Research Journal. All rights reserved

RANTES/CCL5 and risk for coronary events: Results from the MONICA/KORA Augsburg case-cohort, Athero-express and CARDIoGRAM studies

Background: The chemokine RANTES (regulated on activation, normal T-cell expressed and secreted)/CCL5 is involved in the pathogenesis of cardiovascular disease in mice, whereas less is known in humans. We hypothesised that its relevance for atherosclerosis should be reflected by associations between CCL5 gene variants, RANTES serum concentrations and protein levels in atherosclerotic plaques and risk for coronary events. Methods and Findings: We conducted a case-cohort study within the population-based MONICA/KORA Augsburg studies. Baseline RANTES serum levels were measured in 363 individuals with incident coronary events and 1,908 non-cases (mean follow-up: 10.2±

The trans-ancestral genomic architecture of glycemic traits

Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 x 10(-8)), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.A trans-ancestry meta-analysis of GWAS of glycemic traits in up to 281,416 individuals identifies 99 novel loci, of which one quarter was found due to the multi-ancestry approach, which also improves fine-mapping of credible variant sets.Diabetes mellitus: pathophysiological changes and therap

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. Methods: The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model—a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates—with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality—which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. Findings: The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2–100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1–290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1–211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4–48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3–37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7–9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. Interpretation: Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. Funding: Bill & Melinda Gates Foundation

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