Aerosols and droplets generated from expiratory events play a critical role in the transmission of infectious respiratory viruses. Increasingly robust evidence has suggested the crucial role of fine aerosols in airborne transmission of respiratory diseases, which is now widely regarded as an important transmission path of COVID-19. In this report, we used CFD modelling to investigate the efficiency of using portable air purifiers containing HEPA filters to reduce airborne aerosols in hospitals and serve as a potential retrofit mitigation strategy. We used a consulting room to set up our simulations because currently the clearance time between consultations is the controlling factor that limits the patient turnover rate. The results suggest the inlet/suction of the air purifier unit should be lifted above the floor to achieve better clearance efficiency, with up to 40% improvement possible. If multiple air purifiers are used, the combined efficiency can increase to 62%. This work provides practical guidance on a mitigation strategy that can be easily implemented in an expedient, cost-effective and rapid manner, and paves the way for developing more science-informed strategies to mitigate the airborne transmission of respiratory infections in hospitals.

ABSTRACfUse of direct bonding molar tubes saves chair side time in orthodontic treatment. It eliminates the need of painful procedure of tooth separation, and discomfort during band adaptation is avoided. By use of direct bonding tubes, oral hygiene improves and danger of decalcification of enamel is avoided.

Bile Salt Hydrolases (BSHs) are enzymes from enteric bacteria that catalyze the hydrolysis of Bile Acids and consequently promote the reduction of cholesterol level in the mammalian body.Out of several reported BSHs, the Enterococcus faecalis BSH (EfBSH) has been reported to have the highest enzymatic activity. Herein, we have investigated the mechanistic details of the EfBSH activity. The study was carried out employing two mutants of EfBSH: E269A and R207A, which shows differential catalytic activity. The mutant E269A exhibits significant loss in the BSH activity with an increased affinity towards the substrate as compared to R207A mutant. Further, R207A was found to be involved in allostery with an increased EfBSH activity towards tauro-conjugated bile acids. The structural and electrostatic force analyses of the active sites of the E269A mutant and the wild type EfBSH (wt EfBSH) revealed that the interaction between Glu21 and Arg207 is the determining factor in maintaining the dynamic allostery and high activity of EfBSH.