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3. A comprehensive study of coupled LBM-DEM with immersed moving boundary

Author

Yang, G. C., Jing, L., Kwok, C. Y., and Sobral, Y. D.

Subjects
Physics - Computational Physics
Abstract

A systematic study is carried out on a fully resolved fluid-particle model which couples the Lattice Boltzmann Method (LBM) and the Discrete Element Method (DEM) using an immersed moving boundary technique. Similar algorithms have been reported in the past decade, however, the roles of major model parameters are yet to be fully understood. To examine various numerical errors, a series of benchmark cases with a wide range of Reynolds number are performed, starting from a single stationary particle to multiple moving particles. It is found that for flow with low and intermediate Reynolds numbers, 20 fluid cells per one particle diameter are necessary to achieve sufficient accuracy (within 5%). For a flow with high Reynolds number, a turbulence model shall be incorporated so that the effects of unresolved small eddies can be captured in an accurate and efficient manner. Besides, the LBM-DEM results are also sensitive to the relaxation time, especially when the spatial resolution is inadequate. A large relaxation time can introduce additional diffusion of fluid momentum into the fluid-particle system, leading to weakened hydrodynamic interactions. By choosing a small relaxation time greater than the lower limit 0.5, a small fluid compressibility error and a strong coupling between fluids and particles can be achieved, at the cost of computational effort. The test cases also demonstrate the capability of LBM-DEM to describe the rheology of particle suspensions by capturing the pore-scale hydrodynamic interactions. Finally, a guideline for quickly establishing a high-quality LBM-DEM model is provided., Comment: 38 pages, 16 figures

Published
2018
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7. The fingerprint of the summer 2018 drought in Europe on ground-based atmospheric CO₂ measurements

Author

Ramonet, M., Ciais, P., Apadula, F., Bartyzel, J., Bastos, A., Bergamaschi, P., Blanc, P. E., Brunner, D., di Torchiarolo, L. Caracciolo, Calzolari, F., Chen, H., Chmura, L., Colomb, A., Conil, S., Cristofanelli, P., Cuevas, E., Curcoll, R., Delmotte, M., di Sarra, A., Emmenegger, L., Forster, G., Frumau, A., Gerbig, C., Gheusi, F., Hammer, S., Haszpra, L., Hatakka, J., Hazan, L., Heliasz, M., Henne, S., Hensen, A., Hermansen, O., Keronen, P., Kivi, R., Komínková, K., Kubistin, D., Laurent, O., Laurila, T., Lavric, J. V., Lehner, I., Lehtinen, K. E. J., Leskinen, A., Leuenberger, M., Levin, I., Lindauer, M., Lopez, M., Myhre, C. Lund, Mammarella, I., Manca, G., Manning, A., Marek, M. V., Marklund, P., Martin, D., Meinhardt, F., Mihalopoulos, N., Mölder, M., Morgui, J. A., Necki, J., O'Doherty, S., O'Dowd, C., Ottosson, M., Philippon, C., Piacentino, S., Pichon, J. M., Plass-Duelmer, C., Resovsky, A., Rivier, L., Rodó, X., Sha, M. K., Scheeren, H. A., Sferlazzo, D., Spain, T. G., Stanley, K. M., Steinbacher, M., Trisolino, P., Vermeulen, A., Vítková, G., Weyrauch, D., Xueref-Remy, I., Yala, K., and Kwok, C. Yver

Published
2020

8. Characterization of base roughness for granular chute flows

Author

Jing, Lu, Kwok, C. Y., Leung, Y. F., and Sobral, Y. D.

Subjects
Physics - Fluid Dynamics, Condensed Matter - Soft Condensed Matter, Nonlinear Sciences - Adaptation and Self-Organizing Systems
Abstract

Base roughness plays an important role to the dynamics of granular flows but is yet poorly understood due to the difficulty of its quantification. For a bumpy base made by spheres, at least two factors should be considered to characterize its geometric roughness, namely the size ratio of base- to flow-particles and the packing of base particles. In this paper, we propose a definition of base roughness, Ra, which is a function of both the size ratio and the packing arrangement of base particles. The function is generalized for random and regular packing of multi-layered spheres, where the range of possible values of Ra is studied, along with the optimal values to create maximum base roughness. The new definition is applied to granular flows down chute in both two- and three-dimensional configurations. It is proven to be a good indicator of slip condi- tion, and a transition occurs from slip to non-slip condition as Ra increases. Critical values of Ra are identified for the construction of a non-slip base. The effects of contact parameters on base velocity are studied, and it is shown that while the coefficient of friction is less influential, normal damping has more profound effect on base velocity at lower values of Ra. The application of present definition to other base geometries is also discussed., Comment: 18 figures

Published
2016
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9. Squeeze expulsion in grain size segregation

Author

Jing, Lu, Kwok, C. Y., and Leung, Y. F.

Subjects
Nonlinear Sciences - Adaptation and Self-Organizing Systems, Condensed Matter - Soft Condensed Matter
Abstract

Grain segregation occurs under various conditions, such as vibration, shear and mixing. In the gravity-driven shear flow, size segregation is triggered by the percolation of small particles through the opened voids (kinetic sieving), and large particles are accumulated in the upper layer. One hypothesis for the upward migration of large particles is the squeeze expulsion mechanism, which remains yet ambiguous due to limited evidences from either physical or numerical experiments. Here we show statistically how the percolation of small particles facilitates the upward movement of large particles. We found that in large particles, the mechanical anisotropy (strong force network) coincides with the geometric anisotropy (contact network), which indicates squeeze, and the connectivity of large particles is much higher when they are squeezed through small particles. The presence of small particles filling the voids hinders the downward movements and provides dynamic steps for the climbing large particles. Furthermore, increasing the coefficient of friction promotes rotation and empowers more large particles to reach the top layer, implying that the climbing particles tend to rotate relative to their neighbors. Our findings of the microstructure and movement pattern of individual particles add new evidences to the mechanism of squeeze expulsion and provide new perspective for the study of segregation., Comment: 5 figures

Published
2016

10. Ground-Based Mobile Measurements to Track Urban Methane Emissions from Natural Gas in 12 Cities across Eight Countries

Author

Vogel, F., Ars, S., Wunch, D., Lavoie, J., Gillespie, L., Maazallahi, H., Röckmann, T., Nęcki, J., Bartyzel, J., Jagoda, P., Lowry, D., France, J., Fernandez, J., Bakkaloglu, S., Fisher, R., Lanoiselle, M., Chen, H., Oudshoorn, M., Yver-Kwok, C., Defratyka, S., Morgui, J. A., Estruch, C., Curcoll, R., Grossi, C., Chen, J., Dietrich, F., Forstmaier, A., Denier van der Gon, H. A.C., Dellaert, S. N.C., Salo, J., Corbu, M., Iancu, S. S., Tudor, A. S., Scarlat, A. I., Calcan, A., Vogel, F., Ars, S., Wunch, D., Lavoie, J., Gillespie, L., Maazallahi, H., Röckmann, T., Nęcki, J., Bartyzel, J., Jagoda, P., Lowry, D., France, J., Fernandez, J., Bakkaloglu, S., Fisher, R., Lanoiselle, M., Chen, H., Oudshoorn, M., Yver-Kwok, C., Defratyka, S., Morgui, J. A., Estruch, C., Curcoll, R., Grossi, C., Chen, J., Dietrich, F., Forstmaier, A., Denier van der Gon, H. A.C., Dellaert, S. N.C., Salo, J., Corbu, M., Iancu, S. S., Tudor, A. S., Scarlat, A. I., and Calcan, A.

Abstract

To mitigate methane emission from urban natural gas distribution systems, it is crucial to understand local leak rates and occurrence rates. To explore urban methane emissions in cities outside the U.S., where significant emissions were found previously, mobile measurements were performed in 12 cities across eight countries. The surveyed cities range from medium size, like Groningen, NL, to large size, like Toronto, CA, and London, UK. Furthermore, this survey spanned across European regions from Barcelona, ES, to Bucharest, RO. The joint analysis of all data allows us to focus on general emission behavior for cities with different infrastructure and environmental conditions. We find that all cities have a spectrum of small, medium, and large methane sources in their domain. The emission rates found follow a heavy-tailed distribution, and the top 10% of emitters account for 60-80% of total emissions, which implies that strategic repair planning could help reduce emissions quickly. Furthermore, we compare our findings with inventory estimates for urban natural gas-related methane emissions from this sector in Europe. While cities with larger reported emissions were found to generally also have larger observed emissions, we find clear discrepancies between observation-based and inventory-based emission estimates for our 12 cities.

Published
2024

11. Key lifestyles and health outcomes across 16 prevalent chronic diseases: A network analysis of an international observational study.

Author

Li, J, Fong, DYT, Lok, KYW, Wong, JYH, Man Ho, M, Choi, EPH, Pandian, V, Davidson, PM, Duan, W, Tarrant, M, Lee, JJ, Lin, C-C, Akingbade, O, Alabdulwahhab, KM, Ahmad, MS, Alboraie, M, Alzahrani, MA, Bilimale, AS, Boonpatcharanon, S, Byiringiro, S, Hasan, MKC, Schettini, LC, Corzo, W, De Leon, JM, De Leon, AS, Deek, H, Efficace, F, El Nayal, MA, El-Raey, F, Ensaldo-Carrasco, E, Escotorin, P, Fadodun, OA, Fawole, IO, Goh, Y-SS, Irawan, D, Khan, NE, Koirala, B, Krishna, A, Kwok, C, Le, TT, Leal, DG, Lezana-Fernández, MÁ, Manirambona, E, Mantoani, LC, Meneses-González, F, Mohamed, IE, Mukeshimana, M, Nguyen, CTM, Nguyen, HTT, Nguyen, KT, Nguyen, ST, Nurumal, MS, Nzabonimana, A, Omer, NAMA, Ogungbe, O, Poon, ACY, Reséndiz-Rodriguez, A, Puang-Ngern, B, Sagun, CG, Shaik, RA, Shankar, NG, Sommer, K, Toro, E, Tran, HTH, Urgel, EL, Uwiringiyimana, E, Vanichbuncha, T, Youssef, N, Li, J, Fong, DYT, Lok, KYW, Wong, JYH, Man Ho, M, Choi, EPH, Pandian, V, Davidson, PM, Duan, W, Tarrant, M, Lee, JJ, Lin, C-C, Akingbade, O, Alabdulwahhab, KM, Ahmad, MS, Alboraie, M, Alzahrani, MA, Bilimale, AS, Boonpatcharanon, S, Byiringiro, S, Hasan, MKC, Schettini, LC, Corzo, W, De Leon, JM, De Leon, AS, Deek, H, Efficace, F, El Nayal, MA, El-Raey, F, Ensaldo-Carrasco, E, Escotorin, P, Fadodun, OA, Fawole, IO, Goh, Y-SS, Irawan, D, Khan, NE, Koirala, B, Krishna, A, Kwok, C, Le, TT, Leal, DG, Lezana-Fernández, MÁ, Manirambona, E, Mantoani, LC, Meneses-González, F, Mohamed, IE, Mukeshimana, M, Nguyen, CTM, Nguyen, HTT, Nguyen, KT, Nguyen, ST, Nurumal, MS, Nzabonimana, A, Omer, NAMA, Ogungbe, O, Poon, ACY, Reséndiz-Rodriguez, A, Puang-Ngern, B, Sagun, CG, Shaik, RA, Shankar, NG, Sommer, K, Toro, E, Tran, HTH, Urgel, EL, Uwiringiyimana, E, Vanichbuncha, T, and Youssef, N

Abstract

BACKGROUND: Central and bridge nodes can drive significant overall improvements within their respective networks. We aimed to identify them in 16 prevalent chronic diseases during the coronavirus disease 2019 (COVID-19) pandemic to guide effective intervention strategies and appropriate resource allocation for most significant holistic lifestyle and health improvements. METHODS: We surveyed 16 512 adults from July 2020 to August 2021 in 30 territories. Participants self-reported their medical histories and the perceived impact of COVID-19 on 18 lifestyle factors and 13 health outcomes. For each disease subgroup, we generated lifestyle, health outcome, and bridge networks. Variables with the highest centrality indices in each were identified central or bridge. We validated these networks using nonparametric and case-dropping subset bootstrapping and confirmed central and bridge variables' significantly higher indices through a centrality difference test. FINDINGS: Among the 48 networks, 44 were validated (all correlation-stability coefficients >0.25). Six central lifestyle factors were identified: less consumption of snacks (for the chronic disease: anxiety), less sugary drinks (cancer, gastric ulcer, hypertension, insomnia, and pre-diabetes), less smoking tobacco (chronic obstructive pulmonary disease), frequency of exercise (depression and fatty liver disease), duration of exercise (irritable bowel syndrome), and overall amount of exercise (autoimmune disease, diabetes, eczema, heart attack, and high cholesterol). Two central health outcomes emerged: less emotional distress (chronic obstructive pulmonary disease, eczema, fatty liver disease, gastric ulcer, heart attack, high cholesterol, hypertension, insomnia, and pre-diabetes) and quality of life (anxiety, autoimmune disease, cancer, depression, diabetes, and irritable bowel syndrome). Four bridge lifestyles were identified: consumption of fruits and vegetables (diabetes, high cholesterol, hypertension, and insom

Published
2024

12. Ground-Based Mobile Measurements to Track Urban Methane Emissions from Natural Gas in 12 Cities across Eight Countries

Author

Sub Atmospheric physics and chemistry, LS Moleculaire Afweer, Dep Gezondheidszorg Landbouwhuisdieren, Sub Organic Chemistry and Catalysis, Marine and Atmospheric Research, Vogel, F., Ars, S., Wunch, D., Lavoie, J., Gillespie, L., Maazallahi, H., Röckmann, T., Nęcki, J., Bartyzel, J., Jagoda, P., Lowry, D., France, J., Fernandez, J., Bakkaloglu, S., Fisher, R., Lanoiselle, M., Chen, H., Oudshoorn, M., Yver-Kwok, C., Defratyka, S., Morgui, J. A., Estruch, C., Curcoll, R., Grossi, C., Chen, J., Dietrich, F., Forstmaier, A., Denier van der Gon, H. A.C., Dellaert, S. N.C., Salo, J., Corbu, M., Iancu, S. S., Tudor, A. S., Scarlat, A. I., Calcan, A., Sub Atmospheric physics and chemistry, LS Moleculaire Afweer, Dep Gezondheidszorg Landbouwhuisdieren, Sub Organic Chemistry and Catalysis, Marine and Atmospheric Research, Vogel, F., Ars, S., Wunch, D., Lavoie, J., Gillespie, L., Maazallahi, H., Röckmann, T., Nęcki, J., Bartyzel, J., Jagoda, P., Lowry, D., France, J., Fernandez, J., Bakkaloglu, S., Fisher, R., Lanoiselle, M., Chen, H., Oudshoorn, M., Yver-Kwok, C., Defratyka, S., Morgui, J. A., Estruch, C., Curcoll, R., Grossi, C., Chen, J., Dietrich, F., Forstmaier, A., Denier van der Gon, H. A.C., Dellaert, S. N.C., Salo, J., Corbu, M., Iancu, S. S., Tudor, A. S., Scarlat, A. I., and Calcan, A.

Published
2024

14. A comparative study of machine learning in predicting the mechanical properties of the deposited AA6061 alloys via additive friction stir deposition

Author

Qiao, Qian, primary, Liu, Quan, additional, Pu, Jiong, additional, Shi, Haixia, additional, Li, Wenxiao, additional, Zhu, Zhixiong, additional, Guo, Dawei, additional, Qian, Hongchang, additional, Zhang, Dawei, additional, Li, Xiaogang, additional, Kwok, C. T., additional, and Tam, L. M., additional

Published
2024
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16. Postnatal maturation of the opioid and endocannabinoid signalling systems within the descending pain pathway of the rat

Author

Kwok, C.

Subjects
612.8, QP501 Animal biochemistry, QU Biochemistry
Abstract

Significant opioid- and endocannabinoid-dependent changes occur within the periaqueductal grey (PAG), rostroventral medulla (RVM) and spinal cord (DH) during postnatal development of the rat (Sprague Dawley). These changes are involved in the differential descending control of spinal excitability between young and mature rats. Microinjection of the µ-opioid receptor (MOR) agonist DAMGO (30ng) into the PAG of rats increased spinal excitability and lowered mechanical threshold to noxious stimuli in postnatal day (P)21 rats, but had inhibitory effects in adults and lacked efficacy in P10 pups. A tonic opioidergic tone within the PAG was revealed in adult rats by intra-PAG microinjection of CTOP (120ng, MOR antagonist) which lowered mechanical thresholds and increased spinal reflex excitability. Spinal adminstration of DAMGO inhibited spinal excitability in all ages yet the magnitude of this was greater in younger animals than in adults. The expression of MOR and related peptides were also investigated using TaqMan RT-PCR and immunohistochemistry. Proopiomelanocortin (POMC) peaked at P21 in the ventral-PAG, and MOR increased significantly in the DH as the animals aged. CB1/CB2 receptor activation by WIN55212 (4µg, CB1/CB2 agonist) and HU210 (4µg, CB1/CB2 receptor agonist) in the PAG, RVM and DH was anti-nociceptive in both young (P10, P21) and adult rats, but GPR55 receptor activation by LPI (12µg, endogenous GPR55 agonist) and AM251 (2.77µg, CB1 antagonist, GPR55 agonist) was exclusively inhibitory in young rats. Micro-injection of LPI into the adult RVM facilitated spinal reflex excitability, suggesting that GPR55 receptor activation in mature animals is pro-nociceptive. The expression of cannabinoid receptors and endocannabinoid-synthesising enzymes was investigated with immunohistochemical and TaqMan RT-PCR techniques. Overall the expression of CB1 receptors and the anandamide synthesising enzyme NAPE-phospholipase D (NAPE-PLD) increased within the descending pain pathway with age, whereas the expression of the 2-AG synthesising enzyme Diacylglycerol lipase α (DAGLα) decreased. These results illustrate that profound differences in the endogenous-opioidergic and endocannabinoid signalling systems occur within the descending pain pathway throughout postnatal development.

Published
2015

22. Osteosarcoma arising in a case of osteofibrous dysplasia of tibia with classic adamantinoma: A case report and literature review

Author

Weiguo Li, Ka-Lok Mak, Tsz W Yau, Tit L Lam, Chak L Chan, Kwok C Lai, Man K Chan, and Sin TB Fong

Subjects
Orthopedic surgery, RD701-811
Abstract

A five-year-old boy presented with left tibial swelling; there was a typical radiological feature of osteofibrous dysplasia. He was observed until the age of 14 years; there was development of aggressive radiological features. Biopsy revealed chondroblastic osteosarcoma. It was excised and the histology revealed chondroblastic osteosarcoma. A small lesion distal to the main tumour revealed adamantinoma within a background of feature of osteofibrous dysplasia. Proximally, feature of osteofibrous dysplasia was identified focally. The finding of adamantinoma over the distal part of the lesion supports that feature of osteofibrous dysplasia may be a precursor of adamantinoma. They may be a spectrum of diseases with multistep neoplastic transformation. The osteosarcoma may be a result of de-differentiation from adamantinoma. This case is remarkable as the patient was only 14 years old and the tumour showed typical features of osteosarcoma, with feature of osteofibrous dysplasia and adamantinoma found in the same specimen. Feature of osteofibrous dysplasia may be a precursor of adamantinoma, and adamantinoma may dedifferentiate into osteosarcoma.

Published
2021
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28. Dietary changes in the first 3 years after breast cancer diagnosis: a prospective Chinese breast cancer cohort study

Author

Lei Y, Ho SC, Cheng A, Kwok C, Cheung KL, He Y, Lee CI, Lee R, and Yeo W

Subjects
breast cancer, dietary change, pre- and post-diagnosis, Chinese women., Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282
Abstract

Yuan-Yuan Lei,1 Suzanne C Ho,2 Ashley Cheng,3 Carol Kwok,3 Ka Li Cheung,1 Yi-Qian He,1 Chi-Kiu Iris Lee,1 Roselle Lee,1 Winnie Yeo1,4 1Department of Clinical Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region, China; 2Division of Epidemiology, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region, China; 3Department of Clinical Oncology, Princess Margaret Hospital, Kwai Chung, Hong Kong Special Administrative Region, China; 4Hong Kong Cancer Institute, State Key Laboratory in Oncology in South China, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region, China Background: The diagnosis of cancer can motivate patients to change their dietary habits. Evidence on changes in dietary intake before and after breast cancer diagnosis in Chinese women has been limited. Patients and methods: In an ongoing prospective cohort study which involved 1,462 Chinese women with early-stage breast cancer, validated food frequency questionnaire was used to assess prediagnostic dietary intake (using questionnaire to recall dietary intake before diagnosis, which completed at baseline, ie, 0–12 months after diagnosis) and postdiagnostic dietary intake at 18-month and 36-month follow-ups after diagnosis. This study quantitatively compared dietary intake across three time points before and after breast cancer diagnosis. Results: Breast cancer patients significantly and continuously increased vegetables and fruits consumption, from 4.54 servings/day at prediagnosis to 5.19 and 5.59 servings/day at 18-month and 36-month follow-ups postdiagnosis, respectively (each compared to baseline, P

Published
2018

36. Global impacts of COVID-19 on lifestyles and health and preparation preferences: An international survey of 30 countries.

Author

Li, J, Fong, DYT, Lok, KYW, Wong, JYH, Man Ho, M, Choi, EPH, Pandian, V, Davidson, PM, Duan, W, Tarrant, M, Lee, JJ, Lin, C-C, Akingbade, O, Alabdulwahhab, KM, Ahmad, MS, Alboraie, M, Alzahrani, MA, Bilimale, AS, Boonpatcharanon, S, Byiringiro, S, Hasan, MKC, Schettini, LC, Corzo, W, De Leon, JM, De Leon, AS, Deek, H, Efficace, F, El Nayal, MA, El-Raey, F, Ensaldo-Carrasco, E, Escotorin, P, Fadodun, OA, Fawole, IO, Goh, Y-SS, Irawan, D, Khan, NE, Koirala, B, Krishna, A, Kwok, C, Le, TT, Leal, DG, Lezana-Fernández, MÁ, Manirambona, E, Mantoani, LC, Meneses-González, F, Mohamed, IE, Mukeshimana, M, Nguyen, CTM, Nguyen, HTT, Nguyen, KT, Nguyen, ST, Nurumal, MS, Nzabonimana, A, Omer, NAMA, Ogungbe, O, Poon, ACY, Reséndiz-Rodriguez, A, Puang-Ngern, B, Sagun, CG, Shaik, RA, Shankar, NG, Sommer, K, Toro, E, Tran, HTH, Urgel, EL, Uwiringiyimana, E, Vanichbuncha, T, Youssef, N, Li, J, Fong, DYT, Lok, KYW, Wong, JYH, Man Ho, M, Choi, EPH, Pandian, V, Davidson, PM, Duan, W, Tarrant, M, Lee, JJ, Lin, C-C, Akingbade, O, Alabdulwahhab, KM, Ahmad, MS, Alboraie, M, Alzahrani, MA, Bilimale, AS, Boonpatcharanon, S, Byiringiro, S, Hasan, MKC, Schettini, LC, Corzo, W, De Leon, JM, De Leon, AS, Deek, H, Efficace, F, El Nayal, MA, El-Raey, F, Ensaldo-Carrasco, E, Escotorin, P, Fadodun, OA, Fawole, IO, Goh, Y-SS, Irawan, D, Khan, NE, Koirala, B, Krishna, A, Kwok, C, Le, TT, Leal, DG, Lezana-Fernández, MÁ, Manirambona, E, Mantoani, LC, Meneses-González, F, Mohamed, IE, Mukeshimana, M, Nguyen, CTM, Nguyen, HTT, Nguyen, KT, Nguyen, ST, Nurumal, MS, Nzabonimana, A, Omer, NAMA, Ogungbe, O, Poon, ACY, Reséndiz-Rodriguez, A, Puang-Ngern, B, Sagun, CG, Shaik, RA, Shankar, NG, Sommer, K, Toro, E, Tran, HTH, Urgel, EL, Uwiringiyimana, E, Vanichbuncha, T, and Youssef, N

Abstract

BACKGROUND: The health area being greatest impacted by coronavirus disease 2019 (COVID-19) and residents' perspective to better prepare for future pandemic remain unknown. We aimed to assess and make cross-country and cross-region comparisons of the global impacts of COVID-19 and preparation preferences of pandemic. METHODS: We recruited adults in 30 countries covering all World Health Organization (WHO) regions from July 2020 to August 2021. 5 Likert-point scales were used to measure their perceived change in 32 aspects due to COVID-19 (-2 = substantially reduced to 2 = substantially increased) and perceived importance of 13 preparations (1 = not important to 5 = extremely important). Samples were stratified by age and gender in the corresponding countries. Multidimensional preference analysis displays disparities between 30 countries, WHO regions, economic development levels, and COVID-19 severity levels. RESULTS: 16 512 adults participated, with 10 351 females. Among 32 aspects of impact, the most affected were having a meal at home (mean (m) = 0.84, standard error (SE) = 0.01), cooking at home (m = 0.78, SE = 0.01), social activities (m = -0.68, SE = 0.01), duration of screen time (m = 0.67, SE = 0.01), and duration of sitting (m = 0.59, SE = 0.01). Alcohol (m = -0.36, SE = 0.01) and tobacco (m = -0.38, SE = 0.01) consumption declined moderately. Among 13 preparations, respondents rated medicine delivery (m = 3.50, SE = 0.01), getting prescribed medicine in a hospital visit / follow-up in a community pharmacy (m = 3.37, SE = 0.01), and online shopping (m = 3.33, SE = 0.02) as the most important. The multidimensional preference analysis showed the European Region, Region of the Americas, Western Pacific Region and countries with a high-income level or medium to high COVID-19 severity were more adversely impacted on sitting and screen time duration and social activities, whereas other regions and countries experienced more cooking and eating at home. Countries wit

Published
2023

37. Key lifestyles and interim health outcomes for effective interventions in general populations: A network analysis of a large international observational study.

Author

Li, J, Fong, DYT, Lok, KYW, Wong, JYH, Ho, MM, Choi, EPH, Pandian, V, Davidson, PM, Duan, W, Tarrant, M, Lee, JJ, Lin, C-C, Akingbade, O, Alabdulwahhab, KM, Ahmad, MS, Alboraie, M, Alzahrani, MA, Bilimale, AS, Boonpatcharanon, S, Byiringiro, S, Hasan, MKC, Schettini, LC, Corzo, W, De Leon, JM, De Leon, AS, Deek, H, Efficace, F, El Nayal, MA, El-Raey, F, Ensaldo-Carrasco, E, Escotorin, P, Fadodun, OA, Fawole, IO, Goh, Y-SS, Irawan, D, Khan, NE, Koirala, B, Krishna, A, Kwok, C, Le, TT, Leal, DG, Lezana-Fernández, MÁ, Manirambona, E, Mantoani, LC, Meneses-González, F, Mohamed, IE, Mukeshimana, M, Nguyen, CTM, Nguyen, HTT, Nguyen, KT, Nguyen, ST, Nurumal, MS, Nzabonimana, A, Omer, NAMA, Ogungbe, O, Poon, ACY, Reséndiz-Rodriguez, A, Puang-Ngern, B, Sagun, CG, Shaik, RA, Shankar, NG, Sommer, K, Toro, E, Tran, HTH, Urgel, EL, Uwiringiyimana, E, Vanichbuncha, T, Youssef, N, Li, J, Fong, DYT, Lok, KYW, Wong, JYH, Ho, MM, Choi, EPH, Pandian, V, Davidson, PM, Duan, W, Tarrant, M, Lee, JJ, Lin, C-C, Akingbade, O, Alabdulwahhab, KM, Ahmad, MS, Alboraie, M, Alzahrani, MA, Bilimale, AS, Boonpatcharanon, S, Byiringiro, S, Hasan, MKC, Schettini, LC, Corzo, W, De Leon, JM, De Leon, AS, Deek, H, Efficace, F, El Nayal, MA, El-Raey, F, Ensaldo-Carrasco, E, Escotorin, P, Fadodun, OA, Fawole, IO, Goh, Y-SS, Irawan, D, Khan, NE, Koirala, B, Krishna, A, Kwok, C, Le, TT, Leal, DG, Lezana-Fernández, MÁ, Manirambona, E, Mantoani, LC, Meneses-González, F, Mohamed, IE, Mukeshimana, M, Nguyen, CTM, Nguyen, HTT, Nguyen, KT, Nguyen, ST, Nurumal, MS, Nzabonimana, A, Omer, NAMA, Ogungbe, O, Poon, ACY, Reséndiz-Rodriguez, A, Puang-Ngern, B, Sagun, CG, Shaik, RA, Shankar, NG, Sommer, K, Toro, E, Tran, HTH, Urgel, EL, Uwiringiyimana, E, Vanichbuncha, T, and Youssef, N

Abstract

BACKGROUND: The interconnected nature of lifestyles and interim health outcomes implies the presence of the central lifestyle, central interim health outcome and bridge lifestyle, which are yet to be determined. Modifying these factors holds immense potential for substantial positive changes across all aspects of health and lifestyles. We aimed to identify these factors from a pool of 18 lifestyle factors and 13 interim health outcomes while investigating potential gender and occupation differences. METHODS: An international cross-sectional study was conducted in 30 countries across six World Health Organization regions from July 2020 to August 2021, with 16 512 adults self-reporting changes in 18 lifestyle factors and 13 interim health outcomes since the pandemic. RESULTS: Three networks were computed and tested. The central variables decided by the expected influence centrality were consumption of fruits and vegetables (centrality = 0.98) jointly with less sugary drinks (centrality = 0.93) in the lifestyles network; and quality of life (centrality = 1.00) co-dominant (centrality = 1.00) with less emotional distress in the interim health outcomes network. The overall amount of exercise had the highest bridge expected influence centrality in the bridge network (centrality = 0.51). No significant differences were found in the network global strength or the centrality of the aforementioned key variables within each network between males and females or health workers and non-health workers (all P-values >0.05 after Holm-Bonferroni correction). CONCLUSIONS: Consumption of fruits and vegetables, sugary drinks, quality of life, emotional distress, and the overall amount of exercise are key intervention components for improving overall lifestyle, overall health and overall health via lifestyle in the general population, respectively. Although modifications are needed for all aspects of lifestyle and interim health outcomes, a larger allocation of resources and more intensi

Published
2023

39. Frictional boundary condition for lattice Boltzmann modelling of dense granular flows.

Author

Yang, G. C., Huang, Y. J., Lu, Y., Kwok, C. Y., Sobral, Y. D., and Yao, Q. H.

Subjects
GRANULAR flow, STICK-slip response, COMPUTATIONAL fluid dynamics, LATTICE Boltzmann methods, FLOW simulations, COULOMB friction, FRICTION
Abstract

Hydrodynamic approaches that treat granular materials as a continuum via the homogenization of discrete flow properties have become viable options for efficient predictions of bulk flow behaviours. However, simplified boundary conditions in computational fluid dynamics are often adopted, which have difficulty in describing the complex stick-slip phenomenon at the boundaries. This paper extends the lattice Boltzmann method for granular flow simulations by incorporating a novel frictional boundary condition. The wall slip velocity is first calculated based on the shear rate limited by the Coulomb friction, followed by the reconstruction of unknown density distribution functions through a modified bounce-back scheme. Validation is performed against a unique plane Couette flow configuration, and the analytical solutions for the flow velocity profile and the wall slip velocity, as functions of the friction coefficient, are reproduced by the numerical model. The transition between no-slip and partial-slip regimes is captured well, but the convergence rate drops from second order to first order when slip occurs. The rheological parameters and the basal friction coefficient are calibrated further against the discrete element simulation of a square granular column collapsing over a horizontal bottom plane. It is found that the calibrated continuum model can predict other granular column collapses with different initial aspect ratios and slope inclination angles, including the basal slip and the complex internal flow structures, without any further adjustments to the model parameters. This highlights the generalization ability of the numerical model, which has a wide range of application in granular flow predictions and controls. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
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42. J Clin Exp Dent

Author

Subramani, K., primary, Kwok, C., additional, Napoles, JA., additional, Ren, M., additional, Hua, A., additional, and Heske, C., additional

Published
2023
Full Text
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