Analysis of thermomechanical fatigue of unidirectional titanium metal matrix composites

Thermomechanical fatigue (TMF) data was generated for a Ti-15V-3Cr-3Al-3Sn (Ti-15-3) material reinforced with SCS-6 silicon carbide fibers for both in-phase and out-of-phase thermomechanical cycling. Significant differences in failure mechanisms and fatigue life were noted for in-phase and out-of-phase testing. The purpose of the research is to apply a micromechanical model to the analysis of the data. The analysis predicts the stresses in the fiber and the matrix during the thermal and mechanical cycling by calculating both the thermal and mechanical stresses and their rate-dependent behavior. The rate-dependent behavior of the matrix was characterized and was used to calculate the constituent stresses in the composite. The predicted 0 degree fiber stress range was used to explain the composite failure. It was found that for a given condition, temperature, loading frequency, and time at temperature, the 0 degree fiber stress range may control the fatigue life of the unidirectional composite

Time-dependent deformation of titanium metal matrix composites

A three-dimensional finite element program called VISCOPAC was developed and used to conduct a micromechanics analysis of titanium metal matrix composites. The VISCOPAC program uses a modified Eisenberg-Yen thermo-viscoplastic constitutive model to predict matrix behavior under thermomechanical fatigue loading. The analysis incorporated temperature-dependent elastic properties in the fiber and temperature-dependent viscoplastic properties in the matrix. The material model was described and the necessary material constants were determined experimentally. Fiber-matrix interfacial behavior was analyzed using a discrete fiber-matrix model. The thermal residual stresses due to the fabrication cycle were predicted with a failed interface, The failed interface resulted in lower thermal residual stresses in the matrix and fiber. Stresses due to a uniform transverse load were calculated at two temperatures, room temperature and an elevated temperature of 650 C. At both temperatures, a large stress concentration was calculated when the interface had failed. The results indicate the importance of accuracy accounting for fiber-matrix interface failure and the need for a micromechanics-based analytical technique to understand and predict the behavior of titanium metal matrix composites

A case report of total anomalous pulmonary vein connection in an adult through application of multi-modality imaging

ABSTRACT Total Anomalous Pulmonary Vein Connection (TAPVC) is often reported in neonates and children. This report demonstrates an unusual adult TAPVC that the patient is survived in the fourth decade of life. It was diagnosed via application of echocardiography paired with multi detector-row computed tomography angiography. A 39-year-old man was referred for evaluation of dyspnea and cyanosis at rest worsening with exertion. On physical examination, decreased oxygen saturation, clubbing, and central and peripheral cyanosis were detected. In primary evaluation, large Atrial Septal Defect (ASD) was discovered. Cardiac catheterization showed a large ASD and benign variant of Persistent Left Superior Vena Cava (PLSVC). On Trans-Thoracic Echocardiography (TTE), no pulmonary hypertension was defined in direct contradiction of Eisenmenger syndrome. Due to suspicion of a complex shunt, he underwent Trans-Esophageal Echocardiography (TEE) followed by CT-angiography. Both of these image modalities clearly demonstrated the presence of TAPVC in addition to ostium secundum ASD. Due to the change in the main diagnosis, he underwent surgical correction with immediate and complete relief of both cyanosis and dyspnea after operation. Although some complex congenital heart diseases are usually seen in newborns and infants, their presence in adulthood is not impossible. Thus, some unusual findings similar to presence of cyanosis in the absence of pulmonary hypertension should be questioning. In such cases, alternative imaging studies can provide additional guidance in diagnosis. It is not an infrequent occurrence, as this case underscores, where more complete imaging overturns an initial diagnosis leading to completely different management. Keywords: Computed Tomography Angiography Atrial Septal Defect Echocardiograph

Timely diagnosis of left ventricular posterior wall rupture by echocardiography: A case report

Left ventricular free wall rupture is responsible for up to 10 of in-hospital deaths following myocardial infarction. It is mainly associated with posterolateral myocardial infarction, and its antemortem diagnosis is rarely made. One of the medical complications of myocardial infarction is the rupture of the free wall, which occurs more frequently in the anterolateral wall in hypertensives, women, and those with relatively large transmural myocardial infarction usually 1-4 days after myocardial infarction. We herein present the case of a 66-year-old man suffering inferior wall myocardial infarction with abrupt hemodynamic decompensation 9 days after myocardial infarction. Emergent transthoracic echocardiography revealed massive pericardial effusion with tamponade, containing a large elongated mass measuring 1 x 8cm suggestive of hematoma secondary to cardiac rupture. In urgent cardiac surgery, the posterior wall between the left coronary artery branches was ruptured

Analysis and determination of mercury, cadmium and lead in canned tuna fish marketed in Iran

The objective of this study is to determine mercury, cadmium and lead concentrations in 60 canned tuna fish samples produced and distributed in Iran after digestion by the standard methods of the Association of Official Analytical Chemists. Mercury contents in canned tuna fish were determined by cold vapor atomic absorption spectrophotometry while cadmium and lead were determined by graphite furnace atomic absorption spectrophotometry. The metal contents, expressed in μg g-1wet weight for mercury, cadmium and lead varied from 0.010 to 0.401 (average of 0.125), 0.008 to 0.150 (average of 0.050) and 0.021 to 0.301 (average of 0.096), respectively. The values  were comparable and in the range of the literature values. The results of this study indicate that tuna fish produced and marketed in Iran have concentrations well below the standards of FAO/WHO levels of these toxic metals.Key words: Canned tuna fish, heavy metals, mercury, cadmium, lead

Template-based growth of TiO₂ nanorods by sol-gel process

In this paper, the preparation of TiO2 nanorods by sol-gel-template process has been considered. The prepared sols were characterized by using FTIR spectroscopy, and the obtained nanorods were characterized by X-ray diffraction and SEM microscopy. SEM images show that TiO2 nanorods with uniform diameter of about 100-200 nm and a length of several micrometers. The results of XRD indicated that the TiO₂ nanorods were crystallized in the anatase and rutile phases after annealing to 400-700 ºC up to 2 hours

Intestinal ischemia due to mesenteric vascular thrombosis in a patient with positive SARS-CoV-2 RNA without primary pulmonary symptom: A case report

Coronavirus disease 2019 (COVID-19) is an acute respiratory illness caused by novel coronavirus SARS-CoV-2. The clinical manifestations of this infection have a range and typically include impairment of smell, taste disturbance, cough, fever, and shortness of breath. Gastrointestinal manifestations have been reported in anywhere from 3 to 50 of patients with concomitant SARS-CoV-2 pulmonary infection. Abnormalities in coagulation markers have been reported in patients hospitalized with COVID-19. During this article, we will introduce a patient with COVID 19 but with the most manifestation of abdominal pain due to intestinal ischemia and mesenteric vascular thrombosis. © 2021 The Author(s)

Prognostic significance of lung diffusion capacity and spirometric parameters in relation to hemodynamic status in heart transplant candidates

Introduction: Investigations have described a correlation between the severity of heart failure and the severity of pulmonary function abnormalities. In this study, we investigated the association of resting spirometric parameters, lung diffusion for carbon monoxide (DLCO), and the transfer coefficient (KCO) with hemodynamic variables and outcomes in a cohort of heart transplant candidates. Material and methods: Between January 2018 and January 2020, a total of 100 patients with advanced heart failure who were scheduled for right heart catheterization (RHC) as a pre-transplant evaluation measure were enrolled. Spirometry and DLCO were performed in all patients within 24 hours of their RHC. All selected patients were followed for a median (IQR) time of 6 (2�12) months. The end points of interest were heart failure-related mortality and a combined event involving HF-related mortality, heart transplantation (HTX), and need for the placement of a left ventricular assist device (LVAD). Results: Among 846 patients scheduled for RHC, a total of 100 patients (25 female) with a mean (SD) age of 38.5 (12.8) were enrolled. There was a significant correlation between FEV1/FVC and CVP (r = �0.22, p = 0.02), PCWP (r = �0.4, p < 0.001), mPAP (r = �0.45, p < 0.001), and PVR (r = �0.32, p = 0.001). The cardiac output correlated with DLCO (r = 0.3, p = 0.008). Spirometry parameters, DLCO parameters, and hemodynamic parameters did not correlate with the combined event. Among the several variables, only PVR had an independent association with the combined event. Conclusion: Both mechanical and gas diffusion parameters of the lung were not associated with outcomes in the homogeneous group of heart transplant candidates. © 2021 PTChP

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic