Controlled defect production in monolayer MoS2 via electron irradiation at ultralow accelerating voltages

Control on spatial location and density of defects in 2D materials can be achieved using electron beam irradiation. Conversely, ultralow accelerating voltages (less than or equal to 5kV) are used to measure surface morphology, with no expected defect creation. We find clear signatures of defect creation in monolayer (ML) MoS2 at these voltages. Evolution of E' and A1' Raman modes with electron dose, and appearance of defect activated peaks indicate defect formation. To simulate Raman spectra of MoS2 at realistic defect distributions, while retaining density-functional theory accuracy, we combine machine-learning force fields for phonons and eigenmode projection approach for Raman tensors. Simulated spectra agree with experiments, with sulphur vacancies as suggested defects. We decouple defects, doping and carbonaceous contamination using control (hBN covered and encapsulated MoS2) samples. We observe cryogenic PL quenching and defect peaks, and find that carbonaceous contamination does not affect defect creation. These studies have applications in photonics and quantum emitters.Comment: 35 pages, 19 figures, 4 table

Mammalian microRNA: an important modulator of host-pathogen interactions in human viral infections

MicroRNAs (miRNAs), which are small non-coding RNAs expressed by almost all metazoans, have key roles in the regulation of cell differentiation, organism development and gene expression. Thousands of miRNAs regulating approximately 60æ% of the total human genome have been identified. They regulate genetic expression either by direct cleavage or by translational repression of the target mRNAs recognized through partial complementary base pairing. The active and functional unit of miRNA is its complex with Argonaute proteins known as the microRNA-induced silencing complex (miRISC). De-regulated miRNA expression in the human cell may contribute to a diverse group of disorders including cancer, cardiovascular dysfunctions, liver damage, immunological dysfunction, metabolic syndromes and pathogenic infections. Current day studies have revealed that miRNAs are indeed a pivotal component of host-pathogen interactions and host immune responses toward microorganisms. miRNA is emerging as a tool for genetic study, therapeutic development and diagnosis for human pathogenic infections caused by viruses, bacteria, parasites and fungi. Many pathogens can exploit the host miRNA system for their own benefit such as surviving inside the host cell, replication, pathogenesis and bypassing some host immune barriers, while some express pathogen-encoded miRNA inside the host contributing to their replication, survival and/or latency. In this review, we discuss the role and significance of miRNA in relation to some pathogenic viruses

Host hindrance to HIV-1 replication in monocytes and macrophages

Monocytes and macrophages are targets of HIV-1 infection and play critical roles in multiple aspects of viral pathogenesis. HIV-1 can replicate in blood monocytes, although only a minor proportion of circulating monocytes harbor viral DNA. Resident macrophages in tissues can be infected and function as viral reservoirs. However, their susceptibility to infection, and their capacity to actively replicate the virus, varies greatly depending on the tissue localization and cytokine environment. The susceptibility of monocytes to HIV-1 infection in vitro depends on their differentiation status. Monocytes are refractory to infection and become permissive upon differentiation into macrophages. In addition, the capacity of monocyte-derived macrophages to sustain viral replication varies between individuals. Host determinants regulate HIV-1 replication in monocytes and macrophages, limiting several steps of the viral life-cycle, from viral entry to virus release. Some host factors responsible for HIV-1 restriction are shared with T lymphocytes, but several anti-viral mechanisms are specific to either monocytes or macrophages. Whilst a number of these mechanisms have been identified in monocytes or in monocyte-derived macrophages in vitro, some of them have also been implicated in the regulation of HIV-1 infection in vivo, in particular in the brain and the lung where macrophages are the main cell type infected by HIV-1. This review focuses on cellular factors that have been reported to interfere with HIV-1 infection in monocytes and macrophages, and examines the evidences supporting their role in vivo, highlighting unique aspects of HIV-1 restriction in these two cell types

Evaluation of left ventricular dysfunction after single-chamber pacemaker implantation in patients with normal left ventricular function in a tertiary care institution in South India: An observational study

Background: In pacemaker recipients with preserved left ventricular ejection fraction, there is scant evidence regarding the effect of single-chamber pacing on left ventricular systolic function. The objective of the study was to assess the echocardiographic progression of pacemaker patients with preserved left ventricular ejection fraction at the baseline in relation to the level of right ventricular pacing and indication for pacing. Methodology: The clinical and diagnostic data from 200 patients who had undergone pacemaker implantation during 2018–2019 were analyzed. Of 200 patients, 32 patients were not included in the study in view of their baseline ejection fraction being 4%) after 1 year compared to the baseline. By 1 year, there has been a significant (>10%) change from the baseline in the transannular plane systolic excursion parameter. The left ventricular systolic dysfunction happened in a greater degree in patients with advanced conduction disease compared to those who had sinus node dysfunction. Conclusion: Clinically significant left ventricle dysfunction and right ventricle dysfunction developed in a large number of pacemaker recipients with normal left ventricular function at the baseline

Scale freeness in factor analysis

factor model, principal components, scale free estimates, maximum likelihood, generalized least squares, least squares, loss function, identification,

Psychometric properties of a scale to measure menopause-related symptoms in two ethnicities

Objectives To evaluate the psychometric properties of a scale we constructed to measure menopause-related symptoms in Hispanic and White non-Hispanic women.Methods Items were generated from the literature and clinical experiences. Hispanic (n = 123, 51.34 ± 5.14 years) and White (n = 210, 53.36 ± 4.80 years) women completed the scale and other instruments used to validate respective constructs. A subgroup of 69 women completed our scale a second time.Results Following exploratory factor analysis using the entire sample, confirmatory factor analysis was conducted for Hispanic and White women, separately. The same four-factor model (vasomotor, psychological symptoms, relationship(s), and other symptoms) fit data for both ethnic groups. The coefficient α for internal consistency was 0.852 and 0.849 for the initial and second administration, respectively, and the test-retest reliability was significant (p < 0.001). There were differences in factor scores among groups with different menopausal status. Factor scores were significantly correlated with scores of a global quality-of-life instrument (p ≤ 0.001).Conclusions Our study suggests that the scale is appropriate for use for Hispanic and White non-Hispanic women and is capable of detecting differences among women with different menopause-related symptoms. Menopause-related symptoms measured by the scale were correlated with global quality of life