12 research outputs found

    Electronic structure and estimation of Curie temperature in Ca\u3csub\u3e2\u3c/sub\u3eBIrO\u3csub\u3e6\u3c/sub\u3e(B = Cr, Fe) double perovskites

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    We investigate the electronic and magnetic properties of Ca 2 CrIrO 6 and Ca 2 FeIrO 6 by means of density functional theory. These materials belong to a family of recently synthesized Ca 2 CrOsO 6 whose properties show possible applications in a room temperature regime. Upon replacement of Os by Ir in Ca 2 CrOsO 6, we found the system to exhibit a stable ferrimagnetic configuration with a bandgap of ∼0.25 eV and an effective magnetic moment of ∼2.58 μ B per unit cell. Furthermore, when chemical doping is considered by replacing Cr with Fe and Os with Ir, the material retains the insulating state but with a reduced bandgap of 0.13 eV and large increment in the effective magnetic moment of ∼6.68 μ B per unit cell. These observed behaviors are noted to be the consequence of the cooperative effect of spin-orbit coupling; Coulomb correlations from Cr-3d, Fe-3d, and Ir-5d electrons; and the crystal field effect of the materials. These calculations suggest that by chemical tuning, one can manipulate the bandgap and their effective magnetic moment, which may help in material fabrication for device applications. To check further the suitability and applicability of Ca 2 CrIrO 6 and Ca 2 FeIrO 6 at higher temperatures, we estimate the Curie temperature (T C) by calculating the spin-exchange coupling. We found that our findings are in a valid T C trend similar to other perovskites. Our findings are expected to be useful in experimental synthesis and transport measurement for potential applications in modern technological devices

    Electronic Structure and Magnetic Properties of Double Perovskites Ca2MnIrO6

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    Using the density functional theory formalism, electronic and magnetic properties of double perovskites Ca2MnIrO6  are investigated. We found ferrimagnetic ground state with half-metallic nature in Ca2MnIrO6. The electron-correlation, crystal distortion, and spin-orbit coupling (SOC) plays significant role in dictating the electronic properties in this system. From the density of states calculations, a strong hybridization were noted between O-2p, Ir-5d and Mn-3d states resulting Ca2MnIrO6 to half-metal (HM) with metallic state in spin up channel and insulating state in spin-down channel.  The HM state persists even when SOC is taken into account, though the spin-polarization reduces slightly. We thus predict Ca2MnIrO6  as a new HM ferrimagnet which can be useful for modern technological applications. We further investigated the Curie temperature of Ca2MnIrO6  by calculating the spin-exchange coupling parameters. Our results are found to be comparable with other perovskites. BIBECHANA 19  (2022) 127-13

    Electronic Structure and Magnetic Properties of Double Perovskites Ca2MnIrO6

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    Using the density functional theory formalism, electronic and magnetic properties of double perovskites Ca2MnIrO6  are investigated. We found ferrimagnetic ground state with half-metallic nature in Ca2MnIrO6. The electron-correlation, crystal distortion, and spin-orbit coupling (SOC) plays significant role in dictating the electronic properties in this system. From the density of states calculations, a strong hybridization were noted between O-2p, Ir-5d and Mn-3d states resulting Ca2MnIrO6 to half-metal (HM) with metallic state in spin up channel and insulating state in spin-down channel.  The HM state persists even when SOC is taken into account, though the spin-polarization reduces slightly. We thus predict Ca2MnIrO6  as a new HM ferrimagnet which can be useful for modern technological applications. We further investigated the Curie temperature of Ca2MnIrO6  by calculating the spin-exchange coupling parameters. Our results are found to be comparable with other perovskites. BIBECHANA 19  (2022) 127-13

    Relative Burden of Cancer and Noncancer Mortality Among Long-Term Survivors of Breast, Prostate, and Colorectal Cancer in the US

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    IMPORTANCE: Improvements in cancer outcomes have led to a need to better understand long-term oncologic and nononcologic outcomes and quantify cancer-specific vs noncancer-specific mortality risks among long-term survivors. OBJECTIVE: To assess absolute and relative cancer-specific vs noncancer-specific mortality rates among long-term survivors of cancer, as well as associated risk factors. DESIGN, SETTING, AND PARTICIPANTS: This cohort study included 627 702 patients in the Surveillance, Epidemiology, and End Results cancer registry with breast, prostate, or colorectal cancer who received a diagnosis between January 1, 2003, and December 31, 2014, who received definitive treatment for localized disease and who were alive 5 years after their initial diagnosis (ie, long-term survivors of cancer). Statistical analysis was conducted from November 2022 to January 2023. MAIN OUTCOMES AND MEASURES: Survival time ratios (TRs) were calculated using accelerated failure time models, and the primary outcome of interest examined was death from index cancer vs alternative (nonindex cancer) mortality across breast, prostate, colon, and rectal cancer cohorts. Secondary outcomes included subgroup mortality in cancer-specific risk groups, categorized based on prognostic factors, and proportion of deaths due to cancer-specific vs noncancer-specific causes. Independent variables included age, sex, race and ethnicity, income, residence, stage, grade, estrogen receptor status, progesterone receptor status, prostate-specific antigen level, and Gleason score. Follow-up ended in 2019. RESULTS: The study included 627 702 patients (mean [SD] age, 61.1 [12.3] years; 434 848 women [69.3%]): 364 230 with breast cancer, 118 839 with prostate cancer, and 144 633 with colorectal cancer who survived 5 years or more from an initial diagnosis of early-stage cancer. Factors associated with shorter median cancer-specific survival included stage III disease for breast cancer (TR, 0.54; 95% CI, 0.53-0.55) and colorectal cancer (colon: TR, 0.60; 95% CI, 0.58-0.62; rectal: TR, 0.71; 95% CI, 0.69-0.74), as well as a Gleason score of 8 or higher for prostate cancer (TR, 0.61; 95% CI, 0.58-0.63). For all cancer cohorts, patients at low risk had at least a 3-fold higher noncancer-specific mortality compared with cancer-specific mortality at 10 years of diagnosis. Patients at high risk had a higher cumulative incidence of cancer-specific mortality than noncancer-specific mortality in all cancer cohorts except prostate. CONCLUSIONS AND RELEVANCE: This study is the first to date to examine competing oncologic and nononcologic risks focusing on long-term adult survivors of cancer. Knowledge of the relative risks facing long-term survivors may help provide pragmatic guidance to patients and clinicians regarding the importance of ongoing primary and oncologic-focused care

    Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017

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    Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. Methods: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. Findings: Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs 1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). Interpretation: Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury

    Global, regional, and national age-sex-specific mortality and life expectancy, 1950-2017: a systematic analysis for the Global Burden of Disease Study 2017

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    Background: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. Methods: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. Findings: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. Interpretation: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

    Cardiovascular Risk Assessment in Hemodialysis Patients

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    Cardiovascular diseases are the leading cause of death in hemodialysis patients. We aimed to evaluate non-traditional cardiovascular risk factors: homocysteine, high sensitive C-reactive protein, oxidized LDL antibodies, phosphate, and red cell distribution width in chronic kidney disease patients under maintenance hemodialysis along with traditional cardiovascular risk factors like age, hypertension, diabetes mellitus, among others. A total of 78 diagnosed chronic kidney disease patients under maintenance hemodialysis visiting a tertiary care center were included in the study, of which 59% were male. Hyperhomocysteinemia was present in 79.5% of the participants, with the median homocysteine level being 28.43 µmol/L. The median hsCRP level was 4.74 mg/L, and 59% and 24.4% of the total participants were at high and moderate cardiovascular risk respectively. The median oxidized LDL antibody level was 4235 U/mL, which is within the reference range. The median red cell distribution width was 14.05%, which is within the normal range. Left ventricular hypertrophy, a common cardiovascular disease in such patients, was found in 55.13% of the participants. Serum homocysteine level was significantly higher in patients with left ventricular hypertrophy, whereas serum C- reactive protein level was significantly lower in patients with left ventricular hypertrophy. The mean serum phosphate was 6.23 mg/dL (i.e. higher than normal) and hyperphosphatemia was seen among 76.9% of the patients. The mean age of the patients was 47.5 years, which is distinctly lower when compared to the hemodialysis patients in the Western population. The prevalence of hypertension, diabetes mellitus, and anemia were 95%, 18.25%, and 92.3%, respectively

    Observational study of organisational responses of 17 US hospitals over the first year of the COVID-19 pandemic

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    Objectives The COVID-19 pandemic has required significant modifications of hospital care. The objective of this study was to examine the operational approaches taken by US hospitals over time in response to the COVID-19 pandemic.Design, setting and participants This was a prospective observational study of 17 geographically diverse US hospitals from February 2020 to February 2021.Outcomes and analysis We identified 42 potential pandemic-related strategies and obtained week-to-week data about their use. We calculated descriptive statistics for use of each strategy and plotted percent uptake and weeks used. We assessed the relationship between strategy use and hospital type, geographic region and phase of the pandemic using generalised estimating equations (GEEs), adjusting for weekly county case counts.Results We found heterogeneity in strategy uptake over time, some of which was associated with geographic region and phase of pandemic. We identified a body of strategies that were both commonly used and sustained over time, for example, limiting staff in COVID-19 rooms and increasing telehealth capacity, as well as those that were rarely used and/or not sustained, for example, increasing hospital bed capacity.Conclusions Hospital strategies during the COVID-19 pandemic varied in resource intensity, uptake and duration of use. Such information may be valuable to health systems during the ongoing pandemic and future ones

    Assessment of High-Risk Human Papillomavirus Infections Using Clinician- and Self-Collected Cervical Sampling Methods in Rural Women from Far Western Nepal

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    IntroductionNepal has one of the highest cervical cancer rates in South Asia. Only a few studies in populations from urban areas have investigated type specific distribution of human papillomavirus (HPV) in Nepali women. Data on high-risk HPV (HR-HPV) types are not currently available for rural populations in Nepal. We aimed to assess the distribution of HR- HPV among rural Nepali women while assessing self-collected and clinician-collected cervico-vaginal specimens as sample collection methods for HPV screening.MethodsStudy participants were recruited during a health camp conducted by Nepal Fertility Care Center in Achham District of rural far western Nepal. Women of reproductive age completed a socio-demographic and clinical questionnaire, and provided two specimens; one cervical-vaginal specimen using a self-collection method and another cervical specimen collected by health camp auxiliary nurse midwives during a pelvic examination. All samples were tested for 14 different HR-HPV mRNA and also specific for HPV16/18/45 mRNA.ResultsOf 261 women with both clinician- and self-collected cervical samples, 25 tested positive for HR-HPV, resulting in an overall HR-HPV prevalence of 9.6% (95% confidence Interval [CI]: 6.3-13.8). The overall Kappa value assessing agreement between clinician- and self-collected tests was 0.62 (95% CI: 0.43-0.81), indicating a "good" level of agreement. Abnormal cytology was reported for 8 women. One woman identified with squamous cell carcinoma (SCC), and 7 women with high grade squamous intraepithelial lesions (HSIL). Seven of the 8 women tested positive for HR-HPV (87.5%) in clinician-collected samples and 6 in self-collected samples (75.0%).ConclusionThis is the first study to assess HR-HPV among rural Nepali women. Self-collected sampling methods should be the subject of additional research in Nepal for screening HR-HPV, associated with pre-cancer lesions and cancer, in women in rural areas with limited access to health services
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