Puchanee Larpruenrudee

Bio: Puchanee Larpruenrudee is an academic researcher from University of Technology, Sydney. The author has contributed to research in topics: Lung Disorder. The author has an hindex of 3, co-authored 3 publications receiving 11 citations.

SARS CoV-2 aerosol: How far it can travel to the lower airways?

Abstract: The recent outbreak of the SARS CoV-2 virus has had a significant effect on human respiratory health around the world. The contagious disease infected a large proportion of the world population, resulting in long-term health issues and an excessive mortality rate. The SARS CoV-2 virus can spread as small aerosols and enters the respiratory systems through the oral (nose or mouth) airway. The SARS CoV-2 particle transport to the mouth-throat and upper airways is analyzed by the available literature. Due to the tiny size, the virus can travel to the terminal airways of the respiratory system and form a severe health hazard. There is a gap in the understanding of the SARS CoV-2 particle transport to the terminal airways. The present study investigated the SARS CoV-2 virus particle transport and deposition to the terminal airways in a complex 17-generation lung model. This first-ever study demonstrates how far SARS CoV-2 particles can travel in the respiratory system. ANSYS Fluent solver was used to simulate the virus particle transport during sleep and light and heavy activity conditions. Numerical results demonstrate that a higher percentage of the virus particles are trapped at the upper airways when sleeping and in a light activity condition. More virus particles have lung contact in the right lung than the left lung. A comprehensive lobe specific deposition and deposition concentration study was performed. The results of this study provide a precise knowledge of the SARs CoV-2 particle transport to the lower branches and could help the lung health risk assessment system.

Polydisperse Aerosol Transport and Deposition in Upper Airways of Age-Specific Lung.

Abstract: A comprehensive understanding of airflow characteristics and particle transport in the human lung can be useful in modelling to inform clinical diagnosis, treatment, and management, including prescription medication and risk assessment for rehabilitation. One of the difficulties in clinical treatment of lung disorders lies in the patients’ variable physical lung characteristics caused by age, amongst other factors, such as different lung sizes. A precise understanding of the comparison between different age groups with various flow rates is missing in the literature, and this study aims to analyse the airflow and aerosol transport within the age-specific lung. ANSYS Fluent solver and the large-eddy simulation (LES) model were employed for the numerical simulation. The numerical model was validated with the available literature and the computational results showed airway size-reduction significantly affected airflow and particle transport in the upper airways. This study reports higher deposition at the mouth-throat region for larger diameter particles. The overall deposition efficiency (DE) increased with airway size reduction and flow rate. Lung aging effected the pressure distribution and a higher pressure drop was reported for the aged lung as compared to the younger lung. These findings could inform medical management through individualised simulation of drug-aerosol delivery processes for the patient-specific lung.

How severe acute respiratory syndrome coronavirus-2 aerosol propagates through the age-specific upper airways.

Abstract: The recent outbreak of the COVID-19 causes significant respirational health problems, including high mortality rates worldwide. The deadly corona virus-containing aerosol enters the atmospheric air through sneezing, exhalation, or talking, assembling with the particulate matter, and subsequently transferring to the respiratory system. This recent outbreak illustrates that the severe acute respiratory syndrome (SARS) coronavirus-2 is deadlier for aged people than for other age groups. It is evident that the airway diameter reduces with age, and an accurate understanding of SARS aerosol transport through different elderly people's airways could potentially help the overall respiratory health assessment, which is currently lacking in the literature. This first-ever study investigates SARS COVID-2 aerosol transport in age-specific airway systems. A highly asymmetric age-specific airway model and fluent solver (ANSYS 19.2) are used for the investigation. The computational fluid dynamics measurement predicts higher SARS COVID-2 aerosol concentration in the airway wall for older adults than for younger people. The numerical study reports that the smaller SARS coronavirus-2 aerosol deposition rate in the right lung is higher than that in the left lung, and the opposite scenario occurs for the larger SARS coronavirus-2 aerosol rate. The numerical results show a fluctuating trend of pressure at different generations of the age-specific model. The findings of this study would improve the knowledge of SARS coronavirus-2 aerosol transportation to the upper airways which would thus ameliorate the targeted aerosol drug delivery system.

Is the SARS CoV-2 Omicron Variant Deadlier and More Transmissible Than Delta Variant?

Abstract: Genetic variants of severe acute respiratory syndrome coronavirus (SARS-CoV-2) have been globally surging and devastating many countries around the world. There are at least eleven reported variants dedicated with inevitably catastrophic consequences. In 2021, the most dominant Delta and Omicron variants were estimated to lead to more severity and deaths than other variants. Furthermore, these variants have some contagious characteristics involving high transmissibility, more severe illness, and an increased mortality rate. All outbreaks caused by the Delta variant have been rapidly skyrocketing in infection cases in communities despite tough restrictions in 2021. Apart from it, the United States, the United Kingdom and other high-rate vaccination rollout countries are still wrestling with this trend because the Delta variant can result in a significant number of breakthrough infections. However, the pandemic has changed since the latest SARS-CoV-2 variant in late 2021 in South Africa, Omicron. The preliminary data suggest that the Omicron variant possesses 100-fold greater than the Delta variant in transmissibility. Therefore, this paper aims to review these characteristics based on the available meta-data and information from the first emergence to recent days. Australia and the five most affected countries, including the United States, India, Brazil, France, as well as the United Kingdom, are selected in order to review the transmissibility, severity and fatality due to Delta and Omicron variants. Finally, the vaccination programs for each country are also reviewed as the main factor in prevention.

How severe acute respiratory syndrome coronavirus-2 aerosol propagates through the age-specific upper airways.

Abstract: The recent outbreak of the COVID-19 causes significant respirational health problems, including high mortality rates worldwide. The deadly corona virus-containing aerosol enters the atmospheric air through sneezing, exhalation, or talking, assembling with the particulate matter, and subsequently transferring to the respiratory system. This recent outbreak illustrates that the severe acute respiratory syndrome (SARS) coronavirus-2 is deadlier for aged people than for other age groups. It is evident that the airway diameter reduces with age, and an accurate understanding of SARS aerosol transport through different elderly people's airways could potentially help the overall respiratory health assessment, which is currently lacking in the literature. This first-ever study investigates SARS COVID-2 aerosol transport in age-specific airway systems. A highly asymmetric age-specific airway model and fluent solver (ANSYS 19.2) are used for the investigation. The computational fluid dynamics measurement predicts higher SARS COVID-2 aerosol concentration in the airway wall for older adults than for younger people. The numerical study reports that the smaller SARS coronavirus-2 aerosol deposition rate in the right lung is higher than that in the left lung, and the opposite scenario occurs for the larger SARS coronavirus-2 aerosol rate. The numerical results show a fluctuating trend of pressure at different generations of the age-specific model. The findings of this study would improve the knowledge of SARS coronavirus-2 aerosol transportation to the upper airways which would thus ameliorate the targeted aerosol drug delivery system.

Investigation of the Upper Respiratory Tract of a Male Smoker with Laryngeal Cancer by Inhaling Air Associated with Various Physical Activity Levels

Abstract: Smokers are at a higher risk of laryngeal cancer, which is a type of head and neck cancer in which cancer cells proliferate and can metastasize to other tissues after a tumor has formed. Cigarette smoke greatly reduces the inhaled air quality and can also lead to laryngeal cancer. In this study, the upper airway of a 70-year-old smoker with laryngeal cancer was reconstructed by taking a CT scan using Mimics software. To solve the governing equations, computational fluid dynamics (CFD) with a pressure base approach was used with the help of Ansys 2021 R1 software. As a result, the maximum turbulence intensity occurred in the larynx. At 13 L/min, 55 L/min, and 100 L/min, the maximum turbulence intensity was 1.1, 3.5, and 6.1, respectively. The turbulence intensity in the respiratory system is crucial because it demonstrates the ability to transfer energy. The maximum wall shear stress (WSS) also occurred in the larynx. At 13 L/min, 55 L/min, and 100 L/min, the maximum WSS was 0.62 Pa, 5.4 Pa, and 12.4 Pa, respectively. The WSS index cannot be calculated in vivo and should be calculated in vitro. Excessive WSS in the epiglottis is inappropriate and can lead to an airway obstruction. Furthermore, real mathematical modeling outcomes provide an approach for future prevention, treatment, and management planning by forecasting the zones prone to an acceleration of disease progression. In this regard, accurate computational modeling leads to pre-visualization in surgical planning to define the best reformative techniques to determine the most probable patient condition consequences.

Thermal Effects on SARS-CoV-2 Transmission in Peristaltic Blood Flow: Mathematical Modelling

Abstract: SARS-CoV-2 is a novel viral species that has been identified as a highly infectious disease. Scientists have endeavored to collect essential information to characterize better the behaviour of this virus including droplet transmission and airborne effects. However, it is not clear thus far whether temperature can substantially alter the pandemic trajectory inside the physiological system. The present study aims to investigate how temperature may affect virus transmission in peristaltic blood vessels, and how virus density and diameter, and blood viscosity (i.e. viscosity of carrying fluids) will affect the transmission of the virus in the circulatory system. The modelling deployed assumes that coronavirus with a diameter of 120 and a density of 1 move in the direction of blood flow. The quantity of SARS-CoV-2 virions (entire virus particles) inside a microdroplet is calculated by considering the Kepler conjecture method, and the transmission percentage of viral load is also computed. It is observed that the microdroplet carries less amount of coronavirus particles, so an airborne particle infection is less harmful. Further, computational simulations using the proposed model reveal some interesting insights into how rapidly the SARS-CoV-2 virus propagates in the circulatory system and estimate the infection in blood vessels. From these results, it is found that the small virion ( ) rapidly settles inside the bloodstream and infects tissues; however, the duration of infection is short due to the low viscosity of the blood. Further, the closed packed structure of the virions is loosened in the blood vessel due to blood temperature.

Computational evaluation of drug delivery in human respiratory tract under realistic inhalation

Abstract: In recent years, pulmonary diseases have posed severe health problems because of increasing air pollution. Some of the promising drug delivery devices for administering the active pharmaceutical ingredients through the pulmonary route include a pressurized metered-dose inhaler and dry powder inhaler (DPI) for the management of respiratory illness. The drug settling (deposition) efficiency in different regions of a human respiratory tract (HRT) for different drug particle sizes is computed using the discrete phase model in the current study. A computer tomography-based realistic HRT replica is used for this purpose with different inhalation rates following a realistic inhalation profile through the DPI device. Unsteady flow analysis is carried out in a human respiratory system up to the sixth-generation bronchi. The particle force balance equation is used in the discrete-phase model to simulate the motion of drug particles in the HRT. Low, moderate, and high inhalation rates following realistic inhalation profiles are used in the present study. The particles of larger size are deposited more in the oral cavity and are deposited higher at a higher inhalation rate due to higher inertia force. It is also observed that drug particle size plays a key role in drug delivery through dry powder inhalers. It is also found that drugs should contain smaller-sized particles (called fine particles) to enable their reach in the distal bronchi.