Ultrasound-assisted dual-cloud point extraction with high-performance liquid chromatography-hydride generation atomic fluorescence spectrometry for mercury speciation analysis in environmental water and soil samples.

A method for simultaneous preconcentration and determination of mercury species in water and soil samples was established using high-performance liquid chromatography with hydride generation atomic fluorescence spectrometry after ultrasound-assisted dual-cloud point extraction. The extraction process was divided into two steps. In the first cloud point extraction, inorganic mercury and methylmercury formed chelates with sodium diethyldithiocarbamate and were extracted into Triton X-114 micelles. In the second stage, a displacement reaction between sodium diethyldithiocarbamate-inorganic mercury/methylmercury and l-cysteine occurred, and the analytes entered the l-cysteine aqueous solution under ultrasonication. This aqueous solution was directly introduced to the high-performance liquid chromatography with hydride generation atomic fluorescence spectrometry and the detection was completed within 6 min. Under the optimum experimental conditions, the linear range was 0.10-5.0 µg/L (r ≥0.9993) for inorganic mercury and methylmercury, and the enhancement factors were 15.7 for inorganic mercury and 6.35 for methylmercury. The limits of detection for inorganic mercury and methylmercury were 0.004 and 0.016 µg/L, respectively. The approach was successfully applied to the determination of trace inorganic mercury and methylmercury in water and soil samples with good recoveries (85.3-110%). This method solved the problem of peak fusion of the two analytes and was successfully applied to the speciation analysis of mercury.

Evaluation of an innovative pediatric isolation (PI) bed using fluid dynamics simulation and aerosol isolation efficacy.

Airborne transmission is an important mechanism of spread for both viruses and bacteria in hospitals, with nosocomial infections putting a great burden on public health. In this study, we designed and manufactured a bed for pediatric clinic consultation rooms providing air isolation to protect patients and medical personnel from pathogen transmission. The pediatric isolation bed has several primary efficiency filters and a high-efficiency particulate air filter in the bedside unit. The air circulation between inlet and outlet forms negative pressure to remove the patient's exhaled air timeously and effectively. A computational fluid dynamics model was used to calculate the speed of the airflow and the angle of sampler. Following this, we conducted purification experiments using cigarette smoke, Staphylococcus albus (S. albus) and human adenovirus type 5 (HAdV-5) to demonstrate the isolation efficacy. The results showed that the patient's head should be placed as close to the air inlet hood as possible, and an air intake wind speed of 0.86 m/s was effective. The isolation efficacy of the pediatric isolation bed was demonstrated by computational fluid dynamics technology. The isolation efficiency against cigarette smoke exceeded 91.8%, and against S. albus was greater than 99.8%, while the isolation efficiency against HAdV-5 was 100%. The pediatric isolation bed could be used where isolation wards are unavailable, such as in intensive care units and primary clinical settings, to control hospital acquired infections.

Design of an air isolation and purification (AIP) desk for medical use and characterization of its efficacy in ambient air isolation and purification.

The incidences of nosocomial infections (NIs) are increasing throughout the world, especially for those airborne diseases caused by pathogens or air particulates that float in air. In this study, we designed and manufactured a desk for clinic consultation room air purification and air isolation between doctor and patient. The air isolation and purification (AIP) desk has a high efficiency particulate air (HEPA) filter on the tope and several primary efficiency filters on the sides for air purification. The air circulating between inlet and outlet forms a wind-curtain between doctor and patient. The Computational Fluid Dynamics (CFD) model was used to calculate the speed of the air flow and the angle of sampler. We tested the air purification function of the AIP desk in rooms sized about 3.6 × 2.8 × 2.8 m (L × W × H) and found that the AIP desk could significantly remove the tested air pollutants like smoke particulates and microorganisms like Staphylococcus albus (S. albus)and human adenovirus type 5 (HAdV-5). The wind-curtain can significantly block the exhale air of patient being transmitted to the respiratory area of doctor setting in the opposite of AIP desk. Thus, the AIP desk can be used in hospital setting to reduce the risk of NIs and protect both doctors and patients.