Modelling alternately recurring events using subject specific hazard estimation approach.

The motivation for this paper is to account for subject specific variations in a Cox proportional hazard model for alternating recurrent events. This is done through two sets of frailty components, whose marginal distributions are bound together by a copula function. The likelihood function involves unobservable variables, which requires the use of the EM algorithm.

Arsenic exposure from drinking water and staple food (rice): A field scale study in rural Bengal for assessment of human health risk.

Arsenic is a well-known carcinogen with emerging reports showing a range of health outcomes even for low to moderate levels of exposure. This study deals with arsenic exposure and associated increased lifetime cancer risk for populations in arsenic-endemic regions of rural Bengal, where arsenic-safe drinking water is being supplied at present. We found a median total exposure of inorganic arsenic to be 2.

An analysis of COVID-19 clusters in India : Two case studies on Nizamuddin and Dharavi.

Background: In this study we cluster the districts of India in terms of the spread of COVID-19 and related variables such as population density and the number of specialty hospitals. Simulation using a compartment model is used to provide insight into differences in response to public health interventions. Two case studies of interest from Nizamuddin and Dharavi provide contrasting pictures of the success in curbing spread.

Endemic infections, vaccinations, and variability of SARS-COV2 worldwide epidemiology: A cross-sectional study.

The present article aims to analyze epidemiologic aspects of the novel coronavirus pandemic (COVID-19) over different countries across the globe. While analyzing the overall spread of the disease, clusters of countries could be identified where the population-adjusted number of cases and mortality rates (MRs) were significantly different from the others. To draw a comparison over the countries at the same stage of infection, the nature and spread of the infection was evaluated at the 90th day of the pandemic for each country.

Probing ADP Induced Aggregation Kinetics During Platelet-Nanoparticle Interactions: Functional Dynamics Analysis to Rationalize Safety and Benefits.

Platelets, one of the most sensitive blood cells, can be activated by a range of external and internal stimuli including physical, chemical, physiological, and/or non-physiological agents. Platelets need to respond promptly during injury to maintain blood hemostasis. The time profile of platelet aggregation is very complex, especially in the presence of the agonist adenosine 5'-diphosphate (ADP), and it is difficult to probe such complexity using traditional linear dose response models.

An update on the prevalence of low back pain in Africa: a systematic review and meta-analyses.

Background: Low back pain (LBP) remains a common health problem and one of the most prevalent musculoskeletal conditions found among developed and developing nations. The following paper reports on an updated search of the current literature into the prevalence of LBP among African nations and highlights the specific challenges faced in retrieving epidemiological information in Africa.

Methods: A comprehensive search of all accessible bibliographic databases was conducted.

Deletion diagnostics for the generalised linear mixed model with independent random effects.

The Generalised linear mixed model (GLMM) is widely used for modelling environmental data. However, such data are prone to influential observations, which can distort the estimated exposure-response curve particularly in regions of high exposure. Deletion diagnostics for iterative estimation schemes commonly derive the deleted estimates based on a single iteration of the full system holding certain pivotal quantities such as the information matrix to be constant.

State and national household concentrations of PM2.5 from solid cookfuel use: results from measurements and modeling in India for estimation of the global burden of disease.

Background: Previous global burden of disease (GBD) estimates for household air pollution (HAP) from solid cookfuel use were based on categorical indicators of exposure. Recent progress in GBD methodologies that use integrated-exposure-response (IER) curves for combustion particles required the development of models to quantitatively estimate average HAP levels experienced by large populations. Such models can also serve to inform public health intervention efforts.

Part 1. Short-term effects of air pollution on mortality: results from a time-series analysis in Chennai, India.

This report describes the results of a time-series analysis of the effect of short-term exposure to particulate matter with an aerodynamic diameter < or = 10 pm (PM10) on mortality in metropolitan Chennai, India (formerly Madras). This was one of three sites in India chosen by HEI as part of its Public Health and Air Pollution in Asia (PAPA) initiative. The study involved integration and analysis of retrospective data for the years 2002 through 2004.

Comparison of drinking water, raw rice and cooking of rice as arsenic exposure routes in three contrasting areas of West Bengal, India.

Remediation aimed at reducing human exposure to groundwater arsenic in West Bengal, one of the regions most impacted by this environmental hazard, are currently largely focussed on reducing arsenic in drinking water. Rice and cooking of rice, however, have also been identified as important or potentially important exposure routes. Quantifying the relative importance of these exposure routes is critically required to inform the prioritisation and selection of remediation strategies.

Liposome-mediated amplified detection of cell-secreted matrix metalloproteinase-9.

A liposome-based amplified detection system is presented for the cancer cell secreted pathogenic enzyme matrix metalloproteinase-9 which does not require the use of biological antibodies.

A review of multivariate longitudinal data analysis.

Repeated observation of multiple outcomes is common in biomedical and public health research. Such experiments result in multivariate longitudinal data, which are unique in the sense that they allow the researcher to study the joint evolution of these outcomes over time. Special methods are required to analyse such data because repeated observations on any given response are likely to be correlated over time while multiple responses measured at a given time point will also be correlated.

Arsenic exposure induces genomic hypermethylation.

Gene-specific hypermethylation has previously been detected in Arsenic exposed persons. To monitor the level of whole genome methylation in persons exposed to different levels of Arsenic via drinking water, DNA was extracted from peripheral blood mononuclear cells of 64 persons. Uptake of methyl group from (3)H labeled S-Adenosyl Methionine after incubation of DNA with SssI methylase was measured.

The comparison of alternative smoothing methods for fitting non-linear exposure-response relationships with Cox models in a simulation study.

We examined the behavior of alternative smoothing methods for modeling environmental epidemiology data. Model fit can only be examined when the true exposure-response curve is known and so we used simulation studies to examine the performance of penalized splines (P-splines), restricted cubic splines (RCS), natural splines (NS), and fractional polynomials (FP). Survival data were generated under six plausible exposure-response scenarios with a right skewed exposure distribution, typical of environmental exposures.

Mechanistic studies of the triggered release of liposomal contents by matrix metalloproteinase-9.

Matrix metalloproteinases (MMPs) constitute a class of extracellular-matrix-degrading enzymes overexpressed in many cancers and contribute to the metastatic ability of the cancer cells. We have recently demonstrated that liposomal contents can be released when triggered by the enzyme MMP-9. Herein, we report the results of our mechanistic studies of the MMP-9-triggered release of liposomal contents.

Comparing smoothing techniques in Cox models for exposure-response relationships.

To allow for non-linear exposure-response relationships, we applied flexible non-parametric smoothing techniques to models of time to lung cancer mortality in two occupational cohorts with skewed exposure distributions. We focused on three different smoothing techniques in Cox models: penalized splines, restricted cubic splines, and fractional polynomials. We compared standard software implementations of these three methods based on their visual representation and criterion for model selection.

Additive models for geo-referenced failure time data.

Asthma researchers have found some evidence that geographical variations in susceptibility to asthma could reflect the effect of community level factors such as exposure to violence. Our methodology was motivated by a study of age at onset of asthma among children of inner-city neighbourhoods in East Boston. Cox's proportional hazards model was not appropriate since there was not enough information about the nature of geographical variations so as to impose a parametric relationship.

The regeneration and recycle of chromium etching solutions using concentrator cell membrane technology.

The regeneration of chromium (VI) and the recovery of etched copper from chromium etching solutions by electrodialysis is improved by the addition of a concentrator cell in the catholyte chamber. The concentrator media used are ion-exchange resins or activated carbon cloth. The maximum percentages for the regeneration of chromium and recovery of copper in these systems is however less than 80% and 90% respectively because of the competition between the processes of oxidation of Cr(III) and electrodeposition of copper.

Three new antibiotic producing species of the genus Amycolatopsis, Amycolatopsis balhimycina sp. nov., A. tolypomycina sp. nov., A. vancoresmycina sp. nov., and description of Amycolatopsis keratiniphila subsp. keratiniphila subsp. nov. and A. keratiniphila subsp. nogabecina subsp. nov.

Screening of Indian soils for strains producing antibiotics active against methicillin resistant staphylococci resulted in the isolation of the actinomycetes FH 1894T, ST 101170T, and FH 1893T, producing novel glycopeptide antibiotics and a polyenic compound, respectively. Studies of the cellular fatty acids and the absence of mycolic acids as well as the 16S rRNA gene sequence analysis of the producers indicated their membership to the genus Amycolatopsis. Comparison of genomic and metabolic properties of these strains with known species of this genus indicated that they represent new species for which the names Amycolatopsis balhimycina (type strain FH 1894T, DSM 44591T) and Amycolatopsis vancoresmycina (type strain ST 101170T, DSM 44592T) are proposed.

Antifungal antibiotics.

The search for new drugs against fungal infections is a major challenge to current research in mycotic diseases. The present article reviews the current types of antifungal infections, the current scenario of antifungal antibiotics, and the need and approaches to search for newer antifungal antibiotics and antifungal drug targets.

Mathemycin B, a new antifungal macrolactone from actinomycete species HIL Y-8620959.

A new macrocyclic lactone antibiotic mathemycin B (1) was isolated from the fermentation broth of an Actinomycete sp. culture Y-8620959. The structure of 1 was elucidated by high-resolution MS and interpretation of 2D NMR results.