ABSTRACT
The COVID-19 has spread throughout the world.The number of COVID-19 patients still increase rapidly worldwide.The treatment of the COVID-19 patients attracts attention of the researchers.Diagnosis and Treatment Protocol for COVID-19 indicates that atomization inhalation of Alpha-interferon could be used for the antiviral therapy.To explore the possible method for enhancing the effectiveness of the inhalation treatment,numerical simulation was applied to analyze the treatment of a patient with moderate COVID-19 symptoms.Based on the spiral CT scan images on admission,we analyzed the severity of the lung segments.The geometry of the lung was reconstructed according to the lung segmentations.Drug delivery simulations for droplets with different diameters were carried out at low inhalation flow rate (15 L/min).The numbers of the droplets deposited in the airway those delivered into the deeper lung regions were recorded.The relationship between the initial locations of the droplets and their final destinations were obtained.The results indicate that the overall deep lung delivery efficiency of the droplets decreases with the increase of the Stokes number.The delivery efficiency could be significantly increased,if the droplets could be released from two circular areas at the inlet.This investigation proves that the targeted delivery of the inhalable drug is possible. © 2022 Editorial Office of Chinese Journal of Computational Mechanics. All rights reserved.
ABSTRACT
The novel coronavirus pandemic has resulted in an urgent need to study the risk of infection from aerosols generated during dental care and to conduct a review of infection controls. However, existing studies on aerosol particles related to dental treatment have mainly evaluated only the scattering range. Few studies have been conducted on the specifics of the generation of aerosol particles in clinical settings, their mechanisms and patterns of distribution throughout open or enclosed spaces, the duration that they remain suspended in air, and the amount and size of particles present. To minimize the influence of background particles, laser lights, a high-sensitivity camera, and particle counters were used in a large super clean laboratory to investigate the dynamics of aerosols generated during the operation of dental micromotors. The results indicate that aerosols tend to scatter upward immediately after generation and then gradually disperse into the surroundings. Most of the particles are less than 5 µm in size (only a few are larger), and all particles are widely distributed over the long term. Our research clearly elucidates that aerosols produced in dental care are distributed over a wide area and remain suspended for a considerable time in dental clinics before settling.