Quantitative and qualitative assessment of microbial aerosols in different indoor environments of a dental school clinic.

In the indoor environment of dental clinics, dental staff and patients are exposed to various types of infectious agents transported by aerosols and particles, generated during dental procedures, promoting an increased risk of cross-infection. The aim of this study was to determine the levels and diversity of microbial aerosol in relation to particle load in five different departments of a dental school clinic. The air samples were collected by an active single-stage Andersen sampler during the treatment procedure.

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.

Respiratory Disorders Resulting From Exposure to Low Concentrations of Ammonia: A 5-Year Historical Cohort Study.

Objective: This study aimed to investigate respiratory disorders associated with exposure to low concentrations of ammonia.

Method: This cohort study was conducted on 122 industrial workers. Data gathering were based on the officially registered data, the NMAM 6016 and the American Thoracic Society and European Respiratory Society protocols.

Analysis of occupational accidents among nurses working in hospitals based on safety climate and safety performance: a Bayesian network analysis.

This study aimed to analyze causal relationships among safety climate dimensions, safety performance dimensions and occupational accidents for nurses working in hospitals. Data were gathered from questionnaires filled in by nurses from three public hospitals. To analyze interactions among variables, a Bayesian network (BN) analysis was conducted.

Development of Membrane Hollow Fiber for Determination of Maleic Anhydride in Ambient Air as a Field Sampler.

This research develops a rapid method for sampling and analysis of maleic anhydride (MA) in air using a one-step hollow fiber (HF) membrane in the liquid phase followed by high-performance liquid chromatography. A sampling chamber was prepared for sampling of MA with HF-supported de-ionized water absorbency. Several important parameters, such as sampling flow rate, sampling time, and breakthrough volume (BTV), were optimized at different concentrations using a central composite design.

Ion-pair-based hollow-fiber liquid-phase microextraction combined with high-performance liquid chromatography for the simultaneous determination of urinary benzene, toluene, and styrene metabolites.

In the current study, a novel technique for extraction and determination of trans,trans-muconic acid, hippuric acid, and mandelic acid was developed by means of ion-pair-based hollow fiber liquid-phase microextraction in the three-phase mode. Important factors affecting the extraction efficiency of the method were investigated and optimized. These metabolites were extracted from 10 mL of the source phase into a supported liquid membrane containing 1-octanol and 10% w/v of Aliquat 336 as the ionic carrier followed by high-performance liquid chromatography analysis.

Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid.

This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L sodium chloride, liquid membrane containing 1-octanol with 20% (/) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm.

Development of Hollow-Fiber Liquid-Phase Microextraction Method for Determination of Urinary trans,trans-Muconic Acid as a Biomarker of Benzene Exposure.

For the first time, hollow-fiber liquid-phase microextraction combined with high-performance liquid chromatography-ultraviolet was used to extract trans,trans-muconic acid, in urine samples of workers who had been exposed to benzene. The parameters affecting the metabolite extraction were optimized as follows: the volume of sample solution was 11 mL with pH 2, liquid membrane containing dihexyl ether as the supporter, 15% (w/v) of trioctylphosphine oxide as the carrier, the time of extraction was 120 minutes, and stirring rate was 500 rpm. Organic phase impregnated in the pores of a hollow fiber was extracted into 24 µL solution of 0.

Internet addiction and modeling its risk factors in medical students, iran.

Background: Today's internet is a usual and common method for identifying and fulfilling unknown practices. Internet network has been prepared rapid and comfortable access to information. Internet addiction is a new and attractive subject that has been regarded as behavior-based addiction recently.

Sample preparation followed by high performance liquid chromatographic (HPLC) analysis for monitoring muconic acid as a biomarker of occupational exposure to benzene.

Factors affecting solid phase extraction (SPE) of trans,trans-muconic acid (ttMA), as a benzene biomarker, including sample pH, sample concentration, sample volume, sample flow rate, washing solvent, elution solvent, and type of sorbent were evaluated. Extracted samples were determined by HPLC-UV (high performance liquid chromatography-ultraviolet). The analytical column was C18, UV wave length was 259 nm, and the mobile phase was H(2)O/methanol/acetic acid run at flow rate of 1 ml/min.