50 research outputs found
Direct determination of the ambipolar diffusion length in strained InxGa1−xAs/InP quantum wells by cathodoluminescence
The ambipolar diffusion length is measured in strained InxGa1−xAs/InP quantum wells for several mole fractions in the interval 0.3<x<0.8 by cathodoluminescence. The ambipolar diffusion length is found to have a significantly higher value in the lower indium mole fraction samples corresponding to tensile-strained wells. This longer diffusion length for the tensile samples is consistent with results of carrier lifetime experiments by M. C. Wang, K. Kash, C. E. Zah, R. Bhat, and S. L. Chuang [Appl. Phys. Lett. 62, 166 (1993)]
Underlap Optimization in HFinFET in Presence of Interface Traps
In this work, using 3D device simulation, we perform an extensive gate to
source/drain underlap optimization for the recently proposed hybrid transistor,
HFinFET, to show that the underlap lengths can be suitably tuned to improve the
on-off ratio as well as the subthreshold characteristics in an ultra-short
channel n-type device without significant on performance degradation. We also
show that the underlap knob can be tuned to mitigate the device quality
degradation in presence of interface traps. The obtained results are shown to
be very promising when compared against ITRS 2009 performance projections as
well as published state of the art planar and non-planar Silicon MOSFET data of
comparable gate lengths using standard benchmarking techniques.Comment: 5 pages, 8 figures; Accepted in IEEE Transactions on Nanotechnolog
Alloy disorder effects on the room temperature optical properties of GaInNAs quantum wells
The effect of alloy disorder on the optical density of states and the average
room temperature carrier statistics in GaInNAs quantum wells is discussed. A
red shift between the peak of the room temperature photoluminescence and the
surface photovoltage spectra, that systematically increases with the nitrogen
content within the quantum wells is observed. The relationship between this
Stokes' shift and the absorption linewidth in different samples suggests that
the photoexcited carriers undergo a continuous transition, from being in
quasi-thermal equilibrium with the lattice to being completely trapped by the
quantum dot-like potential fluctuations, as the nitrogen fraction in the alloy
is increased. The values of the 'electron temperature' inferred from the
photoluminescence spectra are found to be consistent with this interpretation.Comment: 3 figure
Role of Hemoglobin and Serum Iron in Oral Submucous Fibrosis: A Clinical Study
Background. Oral submucous fibrosis is a chronic, insidious oral mucosal condition affecting the most parts of the oral cavity with high malignant transformation rate triggered by areca nut chewing, nutritional deficiencies, immunologic processes, and genetic predisposition. OSF causes significant hematological abnormalities resulting in anemia and a decrease in serum iron levels. Aim. The aim of this study was to estimate the hemoglobin and serum iron levels among patients with oral submucous fibrosis and to compare the values with healthy subjects. Materials and Methods. In this hospital-based study 30 diagnosed patients of OSMF and 15 healthy individuals were included, and the values of hemoglobin and serum iron levels were estimated using Sahli's and Ferrene methods. Results. OSMF patients showed significantly lower levels of hemoglobin and serum iron when compared with the healthy subjects. Conclusion. The findings of the study emphasizes on the assessment of hemoglobin and serum iron for patients with oral submucous fibrosis. Also iron therapy should be instituted concomitantly with the initial diagnosis which helps to cease the further progression of the condition. Further extensive studies are indicated to understand the correlation between OSMF and iron deficiency
Mapping translocation breakpoints using a wheat microarray
We report mapping of translocation breakpoints using a microarray. We used complex RNA to compare normal hexaploid wheat (17 000 Mb genome) to a ditelosomic stock missing the short arm of chromosome 1B (1BS) and wheat-rye translocations that replace portions of 1BS with rye 1RS. Transcripts detected by a probe set can come from all three Triticeae genomes in ABD hexaploid wheat, and sequences of homoeologous genes on 1AS, 1BS and 1DS often differ from each other. Absence or replacement of 1BS therefore must sometimes result in patterns within a probe set that deviate from hexaploid wheat. We termed these ‘high variance probe sets’ (HVPs) and examined the extent to which HVPs associated with 1BS aneuploidy are related to rice genes on syntenic rice chromosome 5 short arm (5S). We observed an enrichment of such probe sets to 15–20% of all HVPs, while 1BS represents ∼2% of the total genome. In total 257 HVPs constitute wheat 1BS markers. Two wheat-rye translocations subdivided 1BS HVPs into three groups, allocating translocation breakpoints to narrow intervals defined by rice 5S coordinates. This approach could be extended to the entire wheat genome or any organism with suitable aneuploid or translocation stocks
Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017
Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe
Estimating global injuries morbidity and mortality : methods and data used in the Global Burden of Disease 2017 study
Background While there is a long history of measuring death and disability from injuries, modern research methods must account for the wide spectrum of disability that can occur in an injury, and must provide estimates with sufficient demographic, geographical and temporal detail to be useful for policy makers. The Global Burden of Disease (GBD) 2017 study used methods to provide highly detailed estimates of global injury burden that meet these criteria. Methods In this study, we report and discuss the methods used in GBD 2017 for injury morbidity and mortality burden estimation. In summary, these methods included estimating cause-specific mortality for every cause of injury, and then estimating incidence for every cause of injury. Non-fatal disability for each cause is then calculated based on the probabilities of suffering from different types of bodily injury experienced. Results GBD 2017 produced morbidity and mortality estimates for 38 causes of injury. Estimates were produced in terms of incidence, prevalence, years lived with disability, cause-specific mortality, years of life lost and disability-adjusted life-years for a 28-year period for 22 age groups, 195 countries and both sexes. Conclusions GBD 2017 demonstrated a complex and sophisticated series of analytical steps using the largest known database of morbidity and mortality data on injuries. GBD 2017 results should be used to help inform injury prevention policy making and resource allocation. We also identify important avenues for improving injury burden estimation in the future.Peer reviewe
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection