Pathogenic mutations in ethnic Lebanese Arab patients with high risk for hereditary breast cancer

Background: Breast cancer accounts for 35-40% of cancer in women in Lebanese and Arab countries with 50% of patients (pts) diagnosed before age 50. Prevalence of pathogenic BRCA variants in high-risk pts is 5.6-20% (Abulkhair and El Saghir 2021). 7 BRCA1 and 7 BRCA2 pathogenic variants were found in 5.6% of 250 pts with high hereditary risk breast cancer using amplicon sequencing and MLPA (El Saghir 2015;Poulet 2016). We report results of Next Generation Sequencing (NGS) on selected cases based on Manchester Score. First report in ethnic Lebanese Arab pts. Method(s): Pts prospectively enrolled in 2009-2012. IRB approval secured. Pts signed informed consent. Data collected from medical records. Amplicon and MLPA was done on 250 patients. NGS was done on 100 cases with Manchester Score 14-56. DNAs of the 14 pts previously found to have a pathogenic variant (Manchester Score 10-59) were not re-sequenced. NGS on remaining 150 pts was not done due to Covid-19 pandemic and lack of additional funding. Result(s): NGS showed 7 pathogenic variants, 4 in PALB2 and 3 in ATM. No new BRCA variants were found. Two BRCA2 mutations noted by Amplicon/MLPA reported as VUS in 2015 are reclassified as pathogenic. Total BRCA2 pathogenic variants becomes 9. Total pathogenic variants 23. Risk of having hereditary breast cancer in pts with MS 10-59 is 20% (23/ 114), and at least 9.2% in the entire cohort (23/250). Age <=40 with family history (FH) carries 18.9% risk of harboring a pathogenic mutation while no FH, 1.4% (Table 1). All BRCA1 pts had triple negative and 7/9 BRCA2 pts had hormone receptor positive breast cancer. 4 unrelated pts shared the same c.1056_1057delGA PALB2 pathogenic variant thus we suggest this is a founder mutation in Lebanese Ethnic Arab population. Conclusion(s): Mutation rates in high hereditary risk pts with Manchester Score range 10-59 is 20%. Age <=40 with positive FH can be used to select pts for testing when resources are limited. Our data suggests that c.1056_1057delGA is a PALB2 founder mutation. No conflict of interest.Copyright © 2022 Elsevier Ltd. All rights reserved

Effectiveness of RANS in predicting indoor airborne viral transmission: A critical evaluation against LES

We investigate the dispersal of droplet nuclei inside a canonical room of size 10×10×3.2m3 with a four-way cassette air-conditioning unit placed at the center of the ceiling. We use Reynolds averaged Navier–Stokes (RANS) simulations with three flow rates corresponding to air changes per hour (ACH) values of 2.5, 5, and 10. The room setup as well as the operating conditions are chosen to match those of a recent high-fidelity large eddy simulation (LES) study. We use statistical overloading with a total of one million droplet nuclei being initially distributed randomly with uniform probability within the room. Six nuclei sizes are considered ranging in radius from 0.1 to 10μm (166,667 nuclei per size). The simulations are one-way coupled and employ the Langevin equations to model sub-grid motion. The flow and particle statistics are compared against the reference LES simulations, and we find that the RANS k−ɛ realizable model may be used as a computationally cheaper alternative to LES for predicting pathogen concentration in confined spaces albeit, with potentially increased statistical discrepancy. © 2023 Elsevier Ltd

Sensitivity of puff dynamics and airborne droplet nuclei distribution to variations in violent expiration events

We use large eddy simulations to investigate the puff and droplet dynamics from violent expiratory events such as coughs and sneezes in the first few seconds following an ejection. For each of the eleven simulations considered, over 60,000 droplets are ejected and individually tracked using the point-particle Euler–Lagrange approach. We test the sensitivity of the puff and droplet dynamics to various parameters including the ejection volume, momentum, and orientation. We also explore the effect of the mouth shape on the aforementioned dynamics by considering elliptical and circular inlet cross-sections. The results from the simulations compare favorably with a recent theoretical framework put forth by Balachandar et al. (2020) in terms of the puff size and propagation velocity. More importantly however, the theory is able to accurately predict the number and size spectra of the potentially virus-laden droplet nuclei that remain airborne within the puff. We observe that the ejection angle and mouth shape do not significantly affect the puff and droplet dynamics. Additionally, we quantify the carrying capacity of the detached puff portions in terms of the number and size spectra of droplets/droplet nuclei suspended within. © 2022 Elsevier Ltd

ON THE EJECTION SCALE PROBLEM OF EXPIRATORY EVENTS FROM THEORY AND SIMULATIONS

The overall purpose of this study is to investigate expiratory events such as coughs and sneezes in the ejection scale framework, i.e. within a short time span immediately after the expiration process. We conducted large eddy simulations (LES) and compared the results with a recent theoretical model put forth by Balachandar et al. [2]. The theoretical model [2] has been formulated to estimate the evolution of expiratory events such as coughs and sneezes. Some of the key features of the model include estimates for the time evolution of the puff centroid, its size, as well as the number and size of droplets suspended within. The theoretical model includes closure parameters that have been obtained from LES [6, 7]. The simulations cover a wide range of parameters, such as the ejection volume of the puff, its momentum, the ejection angle (whether horizontal, inclined, or vertical), and the ambient humidity. One of the important findings is that while certain aspects such as the front-most location and the lateral extent of the puff, show large variability from one realization to the other, global parameters, such as the centroid location, total volume, and buoyancy show are much less sensitive to turbulent fluctuations. The results also indicate that humid ambient conditions favor stronger gravitational settling of the ejected virus-laden droplets, thus decreasing the risk of infection from the dominant airborne route. Furthermore, the simulations highlight a mechanism for transporting a relatively large amount of droplets over distances upward of 2 meters in a time span on the order of one second. This mechanism, which is also observed in experiments, consists of fast moving detached vortex rings that propagate in a seemingly random direction. We further quantify the size and viral content of the detached portions. © 2022 Begell House Inc.. All rights reserved.

Impact of the COVID 19 pandemic on smoking behavior and beliefs among the American University of Beirut community

INTRODUCTION The current COVID-19 outbreak has led to sudden changes in routine and modifications in health behaviors. The study presented here investigates the changes in smoking behavior and beliefs due to the pandemic among a sample of individuals at the American University of Beirut (AUB) in Lebanon, between August and September 2020. METHODS This is a cross-sectional exploratory study based on data collected through an anonymous, web-based questionnaire. We performed descriptive and univariate analysis on sociodemographic factors, smoking practices, smoking behavior changes, and smoking beliefs. RESULTS In all, 197 participants (65.5% never smokers, 8.1% former smokers, and 26.4% current smokers) completed the online survey. Of these, 19.3% reported a change in their smoking behavior in the last four months, with an equal number of participants increasing and decreasing smoking. Univariate analysis showed that fear of contracting coronavirus and personal health concerns were significantly associated with a decrease in smoking. In contrast, the stress associated with the COVID-19 crisis and the economic crisis was associated with an increase in smoking. CONCLUSIONS The current COVID-19 outbreak has resulted in unexpected alterations in routine and changes in health behaviors. A quarter of all participants said they had changed their smoking habits, with an equal percentage saying they had increased or decreased their smoking. Future research is needed to look into changes in smoking behavior in a more representative group.