428 research outputs found
Low temperature tunneling current enhancement in silicide/Si Schottky contacts with nanoscale barrier width
The low temperature electrical behavior of adjacent silicide/Si Schottky
contacts with or without dopant segregation is investigated. The electrical
characteristics are very well modeled by thermionic-field emission for
non-segregated contacts separated by micrometer-sized gaps. Still, an excess of
current occurs at low temperature for short contact separations or
dopant-segregated contacts when the voltage applied to the device is
sufficiently high. From two-dimensional self-consistent non-equilibrium Green's
function simulations, the dependence of the Schottky barrier profile on the
applied voltage, unaccounted for in usual thermionic-field emission models, is
found to be the source of this deviation
Synthetic Low-Field MRI Super-Resolution Via Nested U-Net Architecture
Low-field (LF) MRI scanners have the power to revolutionize medical imaging
by providing a portable and cheaper alternative to high-field MRI scanners.
However, such scanners are usually significantly noisier and lower quality than
their high-field counterparts. The aim of this paper is to improve the SNR and
overall image quality of low-field MRI scans to improve diagnostic capability.
To address this issue, we propose a Nested U-Net neural network architecture
super-resolution algorithm that outperforms previously suggested deep learning
methods with an average PSNR of 78.83 and SSIM of 0.9551. We tested our network
on artificial noisy downsampled synthetic data from a major T1 weighted MRI
image dataset called the T1-mix dataset. One board-certified radiologist scored
25 images on the Likert scale (1-5) assessing overall image quality, anatomical
structure, and diagnostic confidence across our architecture and other
published works (SR DenseNet, Generator Block, SRCNN, etc.). We also introduce
a new type of loss function called natural log mean squared error (NLMSE). In
conclusion, we present a more accurate deep learning method for single image
super-resolution applied to synthetic low-field MRI via a Nested U-Net
architecture
MHC class II deficiency: Report of a novel mutation and special review
The MHC II deficiency is a rare autosomal recessive primary immunodeficiency syndrome
with increased susceptibility to respiratory and gastrointestinal infections, failure to
thrive and early mortality. This syndrome is caused by mutations in transcription regulators of
the MHC II gene and results in development of blind lymphocytes due to the lack of indicatory
MHC II molecules. Despite homogeneity of clinical manifestations of patients with MHC II
deficiency, the genetic defects underlying this disease are heterogeneous. Herein, we report
an Iranian patient with MHC II deficiency harbouring a novel mutation in RFXANK and novel
misleading clinical features. He had ataxic gait and dysarthria from 30 months of age. Epidemiology,
clinical and immunological features, therapeutic options and prognosis of patients with
MHC II are reviewed in this paper.
© 2017 SEICAP. Published by Elsevier Espana, ˜ S.L.U. All rights reserved
Recent observations of peculiar Gamma-ray bursts using 3.6 m Devasthal Optical Telescope (DOT)
India has been actively involved in the follow-up observations of optical
afterglows of gamma-ray bursts (GRBs) for more than two decades, using the
country's meter-class facilities such as the 1.04 m Sampurnanand Telescope, 1.3
m Devasthal Fast Optical Telescope, 2.01 m Himalayan Chandra Telescope along
with many others in the country, utilizing the longitudinal advantage of the
place. However, since 2016, Indian astronomers have embarked on a new era of
exploration by utilizing the country's largest optical telescope, the 3.6 m
Devasthal Optical Telescope (DOT) at the Devasthal Observatory of ARIES
Nainital. This unique telescope has opened up exciting opportunities for
transient study. Starting from the installation itself, the DOT has been
actively performing the target of opportunity (ToO) observations, leading to
many interesting discoveries. Notable achievements include the contributions
towards the discovery of long GRB 211211A arising from a binary merger, the
discovery of the most delayed optical flare from GRB 210204A along with the
very faint optical afterglow (fainter than 25 mag in g-band) of GRB 200412B. We
also successfully observed the optical counterpart of the very-high-energy
(VHE) detected burst GRB 201015A using DOT. Additionally, DOT has been used for
follow-up observations of dark and orphan afterglows, along with the
observations of host galaxies associated with peculiar GRBs. More recently,
DOT's near-IR follow-up capabilities helped us to detect the first near-IR
counterpart (GRB 230409B) using an Indian telescope. In this work, we summarise
the recent discoveries and observations of GRBs using the 3.6 m DOT,
highlighting the significant contributions in revealing the mysteries of these
cosmic transients.Comment: 16 pages, 2 figures, 1 table, accepted for publication in the
Bulletin of Li\`ege Royal Society of Sciences as a part of 3
Belgo-Indian Network for Astronomy and Astrophysics (BINA) workshop, 22-24
March 202
Detection of carbapenemase in acinetobacter baumannii enrolled in the relationship between biofilm formation and antibiotic resistance
Background and objective: Acinetobacter baumannii is a significant pathogenic bacterium in the health system. The ability to resist antimicrobial drugs and biofilm formation gives the considerable capacity to A. baumannii for existing in a harsh environment, enabling this bacterium to cause hospital-acquired infection. Carbapenem is an important treatment option for severe nosocomial infection and patients infected by multidrug-resistant organisms. The main aim of this study is to detect carbapenemase in isolates, and its association with biofilm formation as well as antibiotic resistance.
Methods: Sixty A. baumannii isolates were obtained from several hospital districts in Erbil city. Identification and antimicrobial susceptibility test (AST) of isolates were performed by VITEKII compact system. Phenotypic identification of carbapenem by sCIM also biofilm-forming was detected by 96 well method. Additionally, three antimicrobial agents were used if they were successful in eliminating biofilm formation. .
Results: The majority of the isolates were from sputum, accounting 75% and antibiotic susceptibility showed that the isolates are resistant to the most available antibiotics, and significant of the isolates formed strong biofilm. The sensitivity of meropenem, ceftazidime, and ciprofloxacin were employed for ten isolates of A. baumannii after biofilm formation it was found that biofilm cells need more concentration of antibiotic than planktonic cells then phenotypic detection of carbapenem showed that the overall positive values were 30 (50.0%) for sCIM.
Conclusion: We revealed that most resistant isolates have a greater capacity for biofilm development than sensitivite isolates. Biofilm-producing strains of A. baumannii cannot be killed with the relatively similar concentration of antimicrobial drugs that are needed to kill planktonic cells
Encore: Lightweight Measurement of Web Censorship with Cross-Origin Requests
Despite the pervasiveness of Internet censorship, we have scant data on its
extent, mechanisms, and evolution. Measuring censorship is challenging: it
requires continual measurement of reachability to many target sites from
diverse vantage points. Amassing suitable vantage points for longitudinal
measurement is difficult; existing systems have achieved only small,
short-lived deployments. We observe, however, that most Internet users access
content via Web browsers, and the very nature of Web site design allows
browsers to make requests to domains with different origins than the main Web
page. We present Encore, a system that harnesses cross-origin requests to
measure Web filtering from a diverse set of vantage points without requiring
users to install custom software, enabling longitudinal measurements from many
vantage points. We explain how Encore induces Web clients to perform
cross-origin requests that measure Web filtering, design a distributed platform
for scheduling and collecting these measurements, show the feasibility of a
global-scale deployment with a pilot study and an analysis of potentially
censored Web content, identify several cases of filtering in six months of
measurements, and discuss ethical concerns that would arise with widespread
deployment
Electrochemical-based biosensors for microRNA detection: Nanotechnology comes into view
Nanotechnology plays an undeniable significant role in medical sciences, particularly in the field of biomedicine. Development of several diagnostic procedures in medicine has been possible through the beneficial application of nano-materials, among which electrochemical nano-biosensors can be mentioned. They can be employed to quantify various clinical biomarkers in detection, evaluation, and follow up stages of the illnesses. MicroRNAs, a group of regulatory short RNA fragments, added a new dimension to the management and diagnosis of several diseases. Mature miRNAs are single-stranded RNA molecules approximately 22 nucleotides in length, which regulate a vast range of biological functions from cellular proliferation and death to cancer development and progression. Recently, diagnostic value of miRNAs in various diseases has been demonstrated. There are many traditional methods for detection of miRNAs including northern blotting, quantitative real time PCR (qRT-PCR), microarray technology, nanotechnology-based approaches, and molecular biology tools including miRNA biosensors. In comparison with other techniques, electrochemical nucleic acid biosensor methods exhibit many interesting features, and could play an important role in the future nucleic acid analysis. This review paper provides an overview of some different types of nanotechnology-based biosensors for detection of miRNAs. © 201
Micronutrients in HIV: A Bayesian MetaAnalysis
Background: Approximately 28.5 million people living with HIV are eligible for treatment (CD4&500), but currently have no access to antiretroviral therapy. Reduced serum level of micronutrients is common in HIV disease. Micronutrient supplementation (MNS) may mitigate disease progression and mortality. Objectives: We synthesized evidence on the effect of micronutrient supplementation on mortality and rate of disease progression in HIV disease.
Methods: We searched MEDLINE, EMBASE, the Cochrane Central, AMED and CINAHL databases through December 2014, without language restriction, for studies of greater than 3 micronutrients versus any or no comparator. We built a hierarchical Bayesian random effects model to synthesize results. Inferences are based on the posterior distribution of the population effects; posterior distributions were approximated by Markov chain Monte Carlo in OpenBugs.
Principal Findings: From 2166 initial references, we selected 49 studies for full review and identified eight reporting on disease progression and/or mortality. Bayesian synthesis of data from 2,249 adults in three studies estimated the relative risk of disease progression in subjects on MNS vs. control as 0.62 (95% credible interval, 0.37, 0.96). Median number needed to treat is 8.4 (4.8, 29.9) and the Bayes Factor 53.4. Based on data reporting on 4,095 adults reporting mortality in 7 randomized controlled studies, the RR was 0.84 (0.38, 1.85), NNT is 25 (4.3, ∞).
Conclusions: MNS significantly and substantially slows disease progression in HIV+ adults not on ARV, and possibly reduces mortality. Micronutrient supplements are effective in reducing progression with a posterior probability of 97.9%. Considering MNS low cost and lack of adverse effects, MNS should be standard of care for HIV+ adults not yet on ARV
Reconstruction of baseline time-trace under changing environmental and operational conditions
Compensation of changing environmental and operational conditions (EOC) is often necessary when using guided-wave based techniques for structural health monitoring in real-world applications. Many studies have demonstrated that the effect of changing EOC can mask damage to a degree that a critical defect might not be detected. Several effective strategies, specifically for compensating the temperature variations, have been developed in recent years. However, many other factors, such as changing humidity and boundary conditions or degradation of material properties, have not received much attention. This paper describes a practical method for reconstruction of the baseline time-trace corresponding to the current EOC. Thus, there is no need for differentiation or compensation procedures when using this method for damage diagnosis. It is based on 3D surface measurements of the velocity field near the actuator using laser vibrometry, in conjunction with high-fidelity finite element simulations of guided wave propagation in free from defects structure. To demonstrate the feasibility and efficiency of the proposed method we provide several examples of the reconstruction and damage detection.P. Aryan, A. Kotousov, C.T. Ng and S. Wild
Epidemiological Study of Breast Cancer in Erbil, Kurdistan Region
Breast cancer is the most diagnosed cancer and the second leading cause of cancer death among women in the world. Compared to some other regions in the world, amount of information available about breast cancer epidemiology in the Kurdistan Region of Iraq is scarce. This study is an attempt to enrich our knowledge about different epidemiological aspects of breast cancer in the region since epidemiological studies contribute quite significantly to the current knowledge of environmental and genetic risk factors and to the current treatment strategies for breast cancer. In addition, studies has shown that the past and ongoing research has a massive implication in improving the outcome of this common disease. This work takes all women diagnosed with breast cancer at Nanakaly Hospital in Erbil, Iraq as sample of the study. Patient characteristics were captured then statistical analysis was performed on these data sets. The majority of patients were found to be city dwellers and about 46% were diagnosed at stage II and 40% at stage III. The vast majority of cases tested positive for hormone receptors but negative for HER2
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