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Li H, Khoa ND, Kuga K, Ito K. In silico identification of viral loads in cough-generated droplets - Seamless integrated analysis of CFPD-HCD-EWF. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 246:108073. [PMID: 38341896 DOI: 10.1016/j.cmpb.2024.108073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/19/2024] [Accepted: 02/07/2024] [Indexed: 02/13/2024]
Abstract
BACKGROUND AND OBJECTIVE Respiratory diseases caused by respiratory viruses have significantly threatened public health worldwide. This study presents a comprehensive approach to predict viral dynamics and the generation of stripped droplets within the mucus layer of the respiratory tract during coughing using a larynx-trachea-bifurcation (LTB) model. METHODS This study integrates computational fluid-particle dynamics (CFPD), host-cell dynamics (HCD), and the Eulerian wall film (EWF) model to propose a potential means for seamless integrated analysis. The verified CFPD-HCD coupling model based on a 3D-shell model was used to characterize the severe acute respiratory syndrome, coronavirus 2 (SARS-CoV-2) dynamics in the LTB mucus layer, whereas the EWF model was employed to account for the interfacial fluid to explore the generation mechanism and trace the origin site of droplets exhaled during a coughing event of an infected host. RESULTS The results obtained using CFPD delineated the preferential deposition sites for droplets in the laryngeal and tracheal regions. Thus, the analysis of the HCD model showed that the viral load increased rapidly in the laryngeal region during the peak of infection, whereas there was a growth delay in the tracheal region (up to day 8 after infection). After two weeks of infection, the high viral load gradually migrated towards the glottic region. Interestingly, the EWF model demonstrated a high concentration of exhaled droplets originating from the larynx. The coupling technique indicated a concurrent high viral load in the mucus layer and site of origin of the exhaled droplets. CONCLUSIONS This interdisciplinary research underscores the seamless analysis from initial exposure to virus-laden droplets, the dynamics of viral infection in the LTB mucus layer, and the re-emission from the coughing activities of an infected host. Our efforts aimed to address the complex challenges at the intersection of viral dynamics and respiratory health, which can contribute to a more detailed understanding and targeted prevention of respiratory diseases.
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Affiliation(s)
- Hanyu Li
- Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - Nguyen Dang Khoa
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Japan.
| | - Kazuki Kuga
- Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
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Mori A, Ito S, Sekine T. A revision of the multiple-path particle dosimetry model focusing on tobacco product aerosol dynamics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3796. [PMID: 38185887 DOI: 10.1002/cnm.3796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/15/2023] [Accepted: 11/26/2023] [Indexed: 01/09/2024]
Abstract
To assess the health impact of inhaled aerosols, it is necessary to understand aerosol dynamics and the associated dosimetry in the human respiratory tract. Although several studies have measured or simulated the dosimetry of aerosol constituents, the respiratory tract focus areas have been limited. In particular, the aerosols generated from tobacco products are complex composites and simulating their dynamics in the respiratory tract is challenging. To assess the dosimetry of the aerosol constituents of tobacco products, we developed a revised version of the Multiple-Path Particle Dosimetry (MPPD) model, which employs (1) new geometry based on CT-scanned human respiratory tract data, (2) convective mixing in the oral cavity and deep lung, and (3) constituent partitioning between the tissue and air, and clearance. The sensitivity analysis was conducted using aerosols composed of four major constituents of electronic cigarette (EC) aerosols to investigate the parameters that have a significant impact on the results. In addition, the revised model was run with 4 and 10 constituents in ECs and conventional cigarettes (CCs), respectively. Sensitivity analysis revealed that the new modeling and the physicochemical properties of constituents had a considerable impact on the simulated aerosol concentration and dosimetry. The simulations could be carried out within 3 min even when 10 constituents of CC aerosols were analyzed simultaneously. The revised model based on MPPD is an efficient and easy-to-use tool for understanding the aerosol dynamics of CC and EC constituents and their effect on the human body.
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Affiliation(s)
- Akina Mori
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
| | - Shigeaki Ito
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
| | - Takashi Sekine
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
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Pang Y, Li M, Li F, Lei J, Zhang T. Preliminary study on the E-liquid and aerosol on the neurobehavior of C. elegans. ENVIRONMENT INTERNATIONAL 2023; 179:108180. [PMID: 37690220 DOI: 10.1016/j.envint.2023.108180] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/27/2023] [Accepted: 08/31/2023] [Indexed: 09/12/2023]
Abstract
E-cigarettes, also known as electronic nicotine delivery systems (ENDS), are mainly used among adolescents and young adults. Similar to traditional cigarettes, different concentrations of nicotine are also added to E-cigarette's liquid (E-liquid), but due to the supplementation of chemicals such as propylene glycol (PG), vegetable glycerin (VG) and flavors, it is difficult to determine the risk after using E-cigarettes. And given to the specificity of the aerosol particle composition and atomization process of E-cigarettes, it is necessary to assess the neurotoxic effects of long-term E-cigarettes use. In this study, two commercial nicotine-containing (5%) and nicotine-free E-liquids were diluted to investigate the neurobehavioral changes and addictive tendencies of developing C. elegans after sub-chronic exposure to E-liquid. The results showed that sub-chronic exposure of E-liquid could lead to impaired growth and development of nematodes, abnormal general neuromotor behavior and advanced learning and memory behavior, and nicotine-containing E-liquid could also lead to increased addiction tendency of nematodes. Although the damage effect of nicotine free E-liquid is smaller than that of the nicotine-containing group, its toxic effect cannot be ignored. Further analysis of the neurotoxicity mechanism found that redox imbalance-mediated mitochondrial stress and aging may be important causes of E-liquid-induced biological damage. The biosafety of e-cigarette aerosols was also included in the assessment. The study found that the heated atomization process did not alter the E-liquid components, and E-cigarette aerosols still have the effect of interfering with the growth and development of nematodes and neurobehavior, and its addictive nature is also of concern. This study can provide new ideas for future studies on the neurotoxic effects and safety assessment of the E-cigarettes, and provide theoretical reference for the study on the injury mechanism of E-cigarettes.
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Affiliation(s)
- Yanting Pang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Menghan Li
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Fuxian Li
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Jialin Lei
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Ting Zhang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China.
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Olsen AK, Li D, Li L. Explore the Dosimetric Relationship between the Intake of Chemical Contaminants and Their Occurrence in Blood and Urine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:9526-9537. [PMID: 37347917 PMCID: PMC10324601 DOI: 10.1021/acs.est.2c08470] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/24/2023]
Abstract
The dosimetric relationship between the human intake dose of a chemical contaminant (an "external dose") and its concentrations in bodily fluids such as blood and urine (related to an "internal dose"), often characterized by a dose-to-concentration ratio, has critical applications in exposure science, toxicology, and risk assessment, especially in the "new approach methods" era. However, there is a lack of a mechanistic, systematic understanding of how such a dosimetric relationship depends on fundamental chemical properties, such as partition coefficients and biotransformation half-lives. Here, we investigate this issue using a well-evaluated toxicokinetic model, which links external and internal doses by quantifying the absorption and elimination of chemicals. Results are visualized in a series of chemical partitioning space plots, whereby a chemical's dose-to-concentration ratio can be approximately predicted based on its partitioning between air, water, and octanol phases. Our results indicate that when taken in equal doses, chemicals with low volatility and moderate to high hydrophobicity exhibit the highest concentrations in the blood, and chemicals undergoing significant biotransformation tend to exhibit lower concentrations in comparison to their counterparts undergoing negligible biotransformation but possessing similar partitioning properties. Chemicals with high hydrophilicity have the highest concentrations in urine. Such revealed property dependence is similar for both adults and children and for individuals with normal body weights and with obesity. Overall, insights gained from this study are important in predicting blood and urinary concentrations from exposure information and in determining the exposure rate that produces the blood or urinary concentrations observed in biomonitoring studies.
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Affiliation(s)
- Amy K. Olsen
- School of Public Health, University
of Nevada, Reno, Reno, Nevada 89557-0274, United States
| | - Dingsheng Li
- School of Public Health, University
of Nevada, Reno, Reno, Nevada 89557-0274, United States
| | - Li Li
- School of Public Health, University
of Nevada, Reno, Reno, Nevada 89557-0274, United States
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5
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Kuga K, Kizuka R, Khoa ND, Ito K. Effect of transient breathing cycle on the deposition of micro and nanoparticles on respiratory walls. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 236:107501. [PMID: 37163889 DOI: 10.1016/j.cmpb.2023.107501] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/09/2023] [Accepted: 03/20/2023] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND OBJECTIVE From various perspectives (e.g. inhalation exposure and drug delivery), it is important to provide insights into the behavior of inhaled particles in the human respiratory system. Although most of the experimental and numerical studies have relied on an assumption of steady inhalation, the transient breathing profile is a key factor in particle deposition in the respiratory tract. In this study, particle transportation and deposition were predicted in a realistic human airway model during a breathing cycle and the effects of steady-state and transient flows on the deposition fraction were observed using computational fluid dynamics. METHODS Two transient breathing cycles with different respiratory durations were considered to evaluate the effects of respiration duration on particle transport and deposition characteristics. Two types of steady breathing conditions with corresponding steady-state respiratory volumes were reproduced. The Lagrangian discrete phase model approach was used to investigate particle transportation and deposition under transient breathing conditions. Additionally, the Eulerian approach was used to analyze the transport of nanoparticles in the gas phase. A total of >50,000 monodispersed particles with aerodynamic diameters ranging between 2 nm and 10 μm were selected for comprehensive deposition predictions for particle sizes ranging from the nano- to microscale. RESULTS The predicted results were compared with the experimental data. The particle deposition fraction in the nasal cavity and tracheal regions showed differences between the steady and transient simulations. In addition, particle analysis under steady inhalation conditions cannot accurately predict particle transportation and deposition in the lower airway. Furthermore, the breathing cycle had a significant effect on the deposition fraction of the particles and the behavior of the inhaled particles. CONCLUSIONS Transient simulation mimicking the breathing cycle was observed to be an important factor in accurately predicting the transportation and deposition of particles in the respiratory tract.
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Affiliation(s)
- Kazuki Kuga
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan.
| | - Ryusei Kizuka
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga-shi, Fukuoka 816-8580, Japan
| | - Nguyen Dang Khoa
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga-shi, Fukuoka 816-8580, Japan
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
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Amalia B, Fu M, Tigova O, Ballbè M, Paniello-Castillo B, Castellano Y, Vyzikidou VK, O'Donnell R, Dobson R, Lugo A, Veronese C, Pérez-Ortuño R, Pascual JA, Cortés N, Gil F, Olmedo P, Soriano JB, Boffi R, Ruprecht A, Ancochea J, López MJ, Gallus S, Vardavas C, Semple S, Fernández E. Exposure to secondhand aerosol from electronic cigarettes at homes: A real-life study in four European countries. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 854:158668. [PMID: 36099951 DOI: 10.1016/j.scitotenv.2022.158668] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 06/15/2023]
Abstract
Electronic cigarette (e-cigarette) use emits potentially hazardous compounds and deteriorates indoor air quality. Home is a place where e-cigarettes may frequently be used amid its increasing prohibition in public places. This study assessed the real-life scenario of bystanders' exposure to secondhand e-cigarette aerosol (SHA) at home. A one-week observational study was conducted within the TackSHS project in four countries (Greece, Italy, Spain, and the United Kingdom) in 2019 including: 1) homes of e-cigarette users living together with a non-user/non-smoker; and 2) control homes with no smokers nor e-cigarette users. Indoor airborne nicotine, PM2.5, and PM1.0 concentrations were measured as environmental markers of SHA. Biomarkers, including nicotine and its metabolites, tobacco-specific nitrosamines, propanediol, glycerol, and metals were measured in participants' saliva and urine samples. E-cigarette use characteristics, such as e-cigarette refill liquid's nicotine concentration, e-cigarette type, place of e-cigarette use at home, and frequency of ventilation, were also collected. A total of 29 e-cigarette users' homes and 21 control homes were included. The results showed that the seven-day concentrations of airborne nicotine were quantifiable in 21 (72.4 %) out of 29 e-cigarette users' homes; overall, they were quite low (geometric mean: 0.01 μg/m3; 95 % CI: 0.01-0.02 μg/m3) and were all below the limit of quantification in control homes. Seven-day concentrations of PM2.5 and PM1.0 in e-cigarette and control homes were similar. Airborne nicotine and PM concentrations did not differ according to different e-cigarette use characteristics. Non-users residing with e-cigarette users had low but significantly higher levels of cotinine, 3'-OH-cotinine and 1,2-propanediol in saliva, and cobalt in urine than non-users living in control homes. In conclusion, e-cigarette use at home created bystanders' exposure to SHA regardless of the e-cigarette use characteristics. Further studies are warranted to assess the implications of SHA exposure for smoke-free policy.
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Affiliation(s)
- Beladenta Amalia
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; School of Medicine and Health Sciences, University of Barcelona - UB, Barcelona, Spain; CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - Marcela Fu
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; School of Medicine and Health Sciences, University of Barcelona - UB, Barcelona, Spain; CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain.
| | - Olena Tigova
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; School of Medicine and Health Sciences, University of Barcelona - UB, Barcelona, Spain; CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - Montse Ballbè
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain; Addictions Unit, Institute of Neurosciences, Hospital Clínic de Barcelona, Barcelona, Spain
| | - Blanca Paniello-Castillo
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Yolanda Castellano
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; School of Medicine and Health Sciences, University of Barcelona - UB, Barcelona, Spain; CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - Vergina K Vyzikidou
- Hellenic Cancer Society - George D. Behrakis Research Lab - HCS, Athens, Greece
| | - Rachel O'Donnell
- Institute for Social Marketing and Health, University of Stirling, Stirling, Scotland, United Kingdom of Great Britain and Northern Ireland
| | - Ruaraidh Dobson
- Institute for Social Marketing and Health, University of Stirling, Stirling, Scotland, United Kingdom of Great Britain and Northern Ireland
| | - Alessandra Lugo
- Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri - IRCCS, Milan, Italy
| | - Chiara Veronese
- IRCCS Istituto Nazionale dei Tumori - INT Foundation, Milan, Italy
| | - Raúl Pérez-Ortuño
- Hospital del Mar Medical Research Institute - IMIM, Barcelona, Spain
| | - José A Pascual
- Hospital del Mar Medical Research Institute - IMIM, Barcelona, Spain; Department of Experimental and Health Sciences, University Pompeu Fabra - UPF, Barcelona, Spain
| | - Nuria Cortés
- Agència de Salut Pública de Barcelona - ASPB, Barcelona, Spain
| | - Fernando Gil
- Department of Legal Medicine and Toxicology, School of Medicine, University of Granada - UG, Granada, Spain
| | - Pablo Olmedo
- Department of Legal Medicine and Toxicology, School of Medicine, University of Granada - UG, Granada, Spain
| | - Joan B Soriano
- CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain; Respiratory Department, Hospital Universitario La Princesa, Madrid, Spain
| | - Roberto Boffi
- IRCCS Istituto Nazionale dei Tumori - INT Foundation, Milan, Italy
| | - Ario Ruprecht
- IRCCS Istituto Nazionale dei Tumori - INT Foundation, Milan, Italy
| | - Julio Ancochea
- CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain; Respiratory Department, Hospital Universitario La Princesa, Madrid, Spain
| | - Maria J López
- Agència de Salut Pública de Barcelona - ASPB, Barcelona, Spain; CIBER de Epidemiología y Salud Pública - CIBERESP, Madrid, Spain; Institut d'Investigació Biomèdica Sant Pau - IIB St. Pau, Barcelona, Spain
| | - Silvano Gallus
- Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri - IRCCS, Milan, Italy
| | - Constantine Vardavas
- School of Medicine, University of Crete, Heraklion, Greece; Department of Oral Health Policy and Epidemiology, Harvard School of Dental Medicine, Harvard University, Boston, MA, USA
| | - Sean Semple
- Institute for Social Marketing and Health, University of Stirling, Stirling, Scotland, United Kingdom of Great Britain and Northern Ireland
| | - Esteve Fernández
- Tobacco Control Unit, Catalan Institute of Oncology - ICO, WHO Collaborating Centre for Tobacco Control, L'Hospitalet de Llobregat, Barcelona, Spain; Tobacco Control Research Group, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; School of Medicine and Health Sciences, University of Barcelona - UB, Barcelona, Spain; CIBER Respiratory Diseases - CIBERES, Instituto de Salud Carlos III, Madrid, Spain
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Kuga K, Sakamoto M, Wargocki P, Ito K. Prediction of exhaled carbon dioxide concentration using a computer-simulated person that included alveolar gas exchange. INDOOR AIR 2022; 32:e13079. [PMID: 36040273 DOI: 10.1111/ina.13079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/06/2022] [Accepted: 07/03/2022] [Indexed: 06/15/2023]
Abstract
Accurate prediction of inhaled CO2 concentration and alveolar gas exchange efficiency would improve the prediction of CO2 concentrations around the human body, which is essential for advanced ventilation design in buildings. We therefore, developed a computer-simulated person (CSP) that included a computational fluid dynamics approach. The CSP simulates metabolic heat production at the skin surface and carbon dioxide (CO2 ) gas exchange at the alveoli during the transient breathing cycle. This makes it possible to predict the CO2 distribution around the human body. The numerical model of the CO2 gas exchange mechanism includes both the upper and lower airways and makes it possible to calculate the alveolar CO2 partial pressure; this improves the prediction accuracy. We used the CSP to predict emission rates of metabolically generated CO2 exhaled by a person and assumed that the tidal volume will be unconsciously reduced as a result of exposure to poor indoor air quality. A reduction in tidal volume resulted in a decrease in CO2 emission rates of the same magnitude as was observed in our published experimental data. We also observed that the predicted inhaled CO2 concentration depended on the flow pattern around the human body, as would be expected.
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Affiliation(s)
- Kazuki Kuga
- Faculty of Engineering Sciences, Kyushu University, Kasuga, Japan
| | - Mitsuharu Sakamoto
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-shi, Japan
| | - Pawel Wargocki
- International Centre for Indoor Environment and Energy, Department of Environmental and Resources Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Kasuga, Japan
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Kuga K, Wargocki P, Ito K. Breathing zone and exhaled air re-inhalation rate under transient conditions assessed with a computer-simulated person. INDOOR AIR 2022; 32:e13003. [PMID: 35225397 DOI: 10.1111/ina.13003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/25/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
The breathing zone of an individual indoors is usually defined as a finite region steadily formed in front of a face. Assuming the steady formation of the breathing zone, we propose a procedure for quantitatively identifying a breathing zone formed in front of a human face in the transient condition. This assumption is reasonable considering that the ventilation time scale of human respiration is sufficiently short compared to the ventilation time scale of a room. We used steady-state computational fluid dynamics (CFD) and a computationally simulated person (CSP). We present the probabilistic size of the breathing zone for various postures and breathing conditions. By analyzing unsteady inhalation and exhalation airflow characteristics via a CSP with a respiratory system, we also estimated the direct re-inhalation rate of the exhaled air. The results can be used for developing methods to control the long-term and low-contaminant concentration exposures.
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Affiliation(s)
- Kazuki Kuga
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka, Japan
| | - Pawel Wargocki
- International Centre for Indoor Environment and Energy, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka, Japan
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9
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Kuga K, Ito K, Chen W, Wang P, Fowles J, Kumagai K. Secondary indoor air pollution and passive smoking associated with cannabis smoking using electric cigarette device-demonstrative in silico study. PLoS Comput Biol 2021; 17:e1009004. [PMID: 33983924 PMCID: PMC8148323 DOI: 10.1371/journal.pcbi.1009004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/25/2021] [Accepted: 04/26/2021] [Indexed: 12/02/2022] Open
Abstract
With electronic (e)-liquids containing cannabis components easily available, many anecdotal examples of cannabis vaping using electronic cigarette devices have been reported. For electronic cigarette cannabis vaping, there are potential risks of secondary indoor air pollution from vapers. However, quantitative and accurate prediction of the inhalation and dermal exposure of a passive smoker in the same room is difficult to achieve due to the ethical constraints on subject experiments. The numerical method, i.e., in silico method, is a powerful tool to complement these experiments with real humans. In this study, we adopted a computer-simulated person that has been validated from multiple perspectives for prediction accuracy. We then conducted an in silico study to elucidate secondary indoor air pollution and passive smoking associated with cannabis vaping using an electronic cigarette device in an indoor environment. The aerosols exhaled by a cannabis vaper were confirmed to be a secondary emission source in an indoor environment; non-smokers were exposed to these aerosols via respiratory and dermal pathways. Tetrahydrocannabinol was used as a model chemical compound for the exposure study. Its uptake by the non-smoker through inhalation and dermal exposure under a worst-case scenario was estimated to be 5.9% and 2.6% of the exhaled quantity from an e-cigarette cannabis user, respectively. How can we best mitigate unintended passive smoking in an indoor environment? As marijuana tends to be legalized in more countries, there is an increasing number of cases of vaping cannabis using e-cigarette devices. E-cigarette vaping is presumed to cause relatively low levels of indoor air pollution due to the absence of a direct combustion process. In this study, we developed a numerical simulation model to quantitatively predict the impact of first- and second-hand cannabis vaping in an indoor environment. The study was conducted in response to vulnerable residents who are concerned regarding the deterioration of indoor air quality and informs policymakers of the potential risk of second-hand cannabis vaping exposure.
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Affiliation(s)
- Kazuki Kuga
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka, Japan
- * E-mail:
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka, Japan
| | - Wenhao Chen
- Indoor Air Quality Program, Environmental Health Laboratory, California Department of Public Health, Richmond, California, United States of America
| | - Ping Wang
- Indoor Air Quality Program, Environmental Health Laboratory, California Department of Public Health, Richmond, California, United States of America
| | - Jeff Fowles
- Indoor Air Quality Program, Environmental Health Laboratory, California Department of Public Health, Richmond, California, United States of America
| | - Kazukiyo Kumagai
- Indoor Air Quality Program, Environmental Health Laboratory, California Department of Public Health, Richmond, California, United States of America
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Editorial – Preface to the Special Issue on Numerical Techniques Meet with OR. FOUNDATIONS OF COMPUTING AND DECISION SCIENCES 2021. [DOI: 10.2478/fcds-2021-0001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Abstract
This special issue of the Foundations of Computing and Decision Sciences, titled ”Numerical Techniques Meet with OR”, is devoted to the numerical techniques and their applications in real-world phenomena. The special issue and its editorial present numerical algorithms as they meet with different research topics such as, e.g., from operational research, supply chain management, geometrical structures and Covid-19 effects on financial applications. Besides, the special issue covers instructional information about numerical techniques which are useful for OR research problems and real-world applications on such issues.
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Bhatt JM, Ramphul M, Bush A. An update on controversies in e-cigarettes. Paediatr Respir Rev 2020; 36:75-86. [PMID: 33071065 PMCID: PMC7518964 DOI: 10.1016/j.prrv.2020.09.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022]
Abstract
E-cigarettes are electronic nicotine delivery systems (ENDS) which mimic tobacco smoking without the combustion of tobacco. These devices have been misleadingly marketed as "less harmful" alternatives to conventional smoking tobacco products. The e-liquid in e-cigarettes include nicotine, a humectant and other additives including flavourings, colourants, or adulterants such as bacterial and fungal products. In this review, we discuss the contrasting views of the tobacco lobby and most professional societies. We describe the epidemiology of the use of these devices, with a widespread and significant rise in youth e-cigarette use seen in both the USA and Europe. We also describe what is known about the toxicity and mechanisms of EVALI (e-cigarette or vaping associated lung injury). This characterised by respiratory failure with an intense inflammatory response. The presentations are diverse and clinicians should consider vaping as a possible cause of any unusual respiratory illness in patients who have a history of vaping or other use of e-cigarette-related products. Second hand exposure to e-cigarettes is also harmful through respiration and transdermal absorption. E-cigarettes have a worse acute toxicity than tobacco and their long-term toxicity is unknown, and we advocate for the immediate, most vigorous anti-vaping legislation possible.
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Affiliation(s)
- Jayesh Mahendra Bhatt
- Nottingham University Hospitals NHS Trust, Queen's Medical Centre, Nottingham, NG7 2UH, United Kingdom.
| | - Manisha Ramphul
- Nottingham University Hospitals NHS Trust, Queen's Medical Centre, Nottingham, NG7 2UH, United Kingdom.
| | - Andrew Bush
- Paediatrics and Paediatric Respirology, National Heart and Lung Institute, United Kingdom; Paediatric Chest Physician, Royal Brompton & Harefield NHS Foundation Trust, United Kingdom; Imperial Centre for Paediatrics and Child Health, United Kingdom; Royal Brompton Hospital, Sydney Street, London SW3 6NP, United Kingdom.
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Feng Y, Marchal T, Sperry T, Yi H. Influence of wind and relative humidity on the social distancing effectiveness to prevent COVID-19 airborne transmission: A numerical study. JOURNAL OF AEROSOL SCIENCE 2020; 147:105585. [PMID: 32427227 PMCID: PMC7233256 DOI: 10.1016/j.jaerosci.2020.105585] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 05/17/2023]
Abstract
It has been confirmed that the coronavirus disease 2019 (COVID-19) can transmit through droplets created when an infected human coughs or sneezes. Accordingly, 1.83-m (6-feet) social distancing is advised to reduce the spread of the disease among humans. This is based on the assumption that no air circulation exists around people. However, it is not well investigated whether the ambient wind and relative humidity (RH) will cause SARS-CoV-2 laden droplets to transport farther in the air, and make the current social distancing policy insufficient. To provide evidence and insight into the "social distancing" guidelines, a validated computational fluid-particle dynamics (CFPD) model was employed to simulate the transient transport, condensation/evaporation, and deposition of SARS-CoV-2 laden droplets emitted by coughs, with different environmental wind velocities and RHs. Initial droplet diameters range from 2 to 2000 μm, and the wind velocities range from 0 to 16 km/h, representing different wind forces from calm air to moderate breeze. The comparison between a steady-state wind and a gust with a constant frequency has also been performed. Ambient RHs are 40% and 99.5%. The distances between the two virtual humans are 1.83 m and 3.05 m (6 feet and 10 feet). The facial covering effect on reducing the airborne transmission of the cough droplets has also been evaluated. Numerical results indicate that the ambient wind will enhance the complexity of the secondary flows with recirculation between the two virtual humans. Microdroplets follow the airflow streamlines well and deposit on both human bodies and head regions, even with the 3.05-m (10-feet) separation distance. The rest of the microdroplets can transport in the air farther than 3.05 m (10 feet) due to wind convection, causing a potential health risk to nearby people. High RH will increase the droplet sizes due to the hygroscopic growth effect, which increases the deposition fractions on both humans and the ground. With the complex environmental wind and RH conditions, the 6-feet social distancing policy may not be sufficient to protect the inter-person aerosol transmission, since the suspending micro-droplets were influenced by convection effects and can transport from the human coughs/sneezes to the other human in less than 5 seconds. Due to the complex real-world environmental ventilation conditions, a social distance longer than 1.83 m (6 feet) needs to be considered. Wearing masks should also be recommended for both infected and healthy humans to reduce the airborne cough droplet numbers.
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Affiliation(s)
- Yu Feng
- School of Chemical Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Thierry Marchal
- ANSYS Belgium S.A, Center d'Affaires "Les Collines de Wavre", Avenue Pasteur 4, 1300, Wavre, Belgium
| | - Ted Sperry
- School of Chemical Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Hang Yi
- School of Chemical Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
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Peruzzi M, Cavarretta E, Frati G, Carnevale R, Miraldi F, Biondi-Zoccai G, Sciarretta S, Versaci F, Cammalleri V, Avino P, Protano C, Vitali M. Comparative Indoor Pollution from Glo, Iqos, and Juul, Using Traditional Combustion Cigarettes as Benchmark: Evidence from the Randomized SUR-VAPES AIR Trial. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17176029. [PMID: 32825020 PMCID: PMC7504617 DOI: 10.3390/ijerph17176029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/13/2020] [Accepted: 08/16/2020] [Indexed: 02/05/2023]
Abstract
Modified risk products (MRP) such as electronic vaping cigarettes (EVC) and heat-not-burn cigarettes (HNBC) are appealing alternatives to combustion cigarettes. Limited between- and within-device comparative data are available on MRP. We aimed at comparing indoor particulate matter (PM) emissions measured in a randomized trial enforcing standardized smoking sessions, testing different devices and flavors of MRP, using traditional combustion cigarettes (TCC) as benchmark. Overall, MRP yielded significantly lower levels of indoor PM in comparison to TCC (with median PM levels during smoking for MRP < 100 μg/m3, and for TCC > 1000 μg/m3). Despite this, significant differences among MRP were found, with Iqos appearing associated with a significantly lower burden of emissions for all the monitored fractions of PM, including total PM (all p < 0.05). Precisely, during use, PM ≤1 µm (PM1) emissions were 28 (16; 28) μg/m3 for Glo, 25 (15; 57) μg/m3 for Iqos, and 73 (15; 559) μg/m3 for Juul (p < 0.001 for Glo vs. Iqos, p < 0.001 for Glo vs. Juul, and p = 0.045 for Iqos vs. Juul). Exploratory within-MRP analyses suggested significant differences between flavors, favoring, for instance, Ultramarine for Glo, Bronze for Iqos, and Mango for Juul, even if results varied substantially according to individual smoker. In conclusion, leading MRP have significantly less intense and persistent effects on indoor pollution in comparison to TCC. Yet, when focusing solely on MRP, between-product and between-flavor differences appear, with quantitative estimates suggesting lower polluting effects with Iqos. These results, if confirmed externally, could be used to individualize product and flavor choice to minimize the untoward effects of EVC and HNBC on indoor pollution.
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Affiliation(s)
- Mariangela Peruzzi
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 74, 04100 Latina, Italy; (E.C.); (G.F.); (R.C.); (G.B.-Z.); (S.S.)
- Mediterranea Cardiocentro, 80122 Naples, Italy
- Correspondence: or
| | - Elena Cavarretta
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 74, 04100 Latina, Italy; (E.C.); (G.F.); (R.C.); (G.B.-Z.); (S.S.)
- Mediterranea Cardiocentro, 80122 Naples, Italy
| | - Giacomo Frati
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 74, 04100 Latina, Italy; (E.C.); (G.F.); (R.C.); (G.B.-Z.); (S.S.)
- IRCCS NEUROMED, 86077 Pozzilli, Italy
| | - Roberto Carnevale
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 74, 04100 Latina, Italy; (E.C.); (G.F.); (R.C.); (G.B.-Z.); (S.S.)
- Mediterranea Cardiocentro, 80122 Naples, Italy
| | - Fabio Miraldi
- Department of Clinical, Internal Medicine, Anesthesiology and Cardiovascular Sciences, Sapienza University of Rome, Viale Del Policlinico 155, 00161 Rome, Italy;
| | - Giuseppe Biondi-Zoccai
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 74, 04100 Latina, Italy; (E.C.); (G.F.); (R.C.); (G.B.-Z.); (S.S.)
- Mediterranea Cardiocentro, 80122 Naples, Italy
| | - Sebastiano Sciarretta
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 74, 04100 Latina, Italy; (E.C.); (G.F.); (R.C.); (G.B.-Z.); (S.S.)
- IRCCS NEUROMED, 86077 Pozzilli, Italy
| | - Francesco Versaci
- UOC UTIC Emodinamica e Cardiologia, Ospedale Santa Maria Goretti, Via Antonio Canova, 04100 Latina, Italy;
| | - Vittoria Cammalleri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (V.C.); (C.P.); (M.V.)
| | - Pasquale Avino
- Department of Agricultural, Environmental and Food Sciences (DiAAA), University of Molise, via De Sanctis, 86100 Campobasso, Italy;
| | - Carmela Protano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (V.C.); (C.P.); (M.V.)
| | - Matteo Vitali
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (V.C.); (C.P.); (M.V.)
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