Publications by authors named "Samuel Faucher"

4 Publications

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A virucidal face mask based on the reverse-flow reactor concept for thermal inactivation of SARS-CoV-2.

AIChE J 2021 Mar 14:e17250. Epub 2021 Mar 14.

Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA.

While facial coverings reduce the spread of SARS-CoV-2 by viral filtration, masks capable of viral inactivation by heating can provide a complementary method to limit transmission. Inspired by reverse-flow chemical reactors, we introduce a new virucidal face mask concept driven by the oscillatory flow of human breath. The governing heat and mass transport equations are solved to evaluate virus and CO transport. Given limits imposed by the kinetics of SARS-CoV-2 thermal inactivation, human breath, safety, and comfort, heated masks may inactivate SARS-CoV-2 to medical-grade sterility. We detail one design, with a volume of 300 ml at 90°C that achieves a 3-log reduction in viral load with minimal impedance within the mask mesh, with partition coefficient around 2. This is the first quantitative analysis of virucidal thermal inactivation within a protective face mask, and addresses a pressing need for new approaches for personal protective equipment during a global pandemic.
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http://dx.doi.org/10.1002/aic.17250DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7995042PMC
March 2021

Diameter Dependence of Water Filling in Lithographically Segmented Isolated Carbon Nanotubes.

ACS Nano 2021 Feb 29;15(2):2778-2790. Epub 2021 Jan 29.

Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.

Although the structure and properties of water under conditions of extreme confinement are fundamentally important for a variety of applications, they remain poorly understood, especially for dimensions less than 2 nm. This problem is confounded by the difficulty in controlling surface roughness and dimensionality in fabricated nanochannels, contributing to a dearth of experimental platforms capable of carrying out the necessary precision measurements. In this work, we utilize an experimental platform based on the interior of lithographically segmented, isolated single-walled carbon nanotubes to study water under extreme nanoscale confinement. This platform generates multiple copies of nanotubes with identical chirality, of diameters from 0.8 to 2.5 nm and lengths spanning 6 to 160 μm, that can be studied individually in real time before and after opening, exposure to water, and subsequent water filling. We demonstrate that, under controlled conditions, the diameter-dependent blue shift of the Raman radial breathing mode (RBM) between 1 and 8 cm measures an increase in the interior mechanical modulus associated with liquid water filling, with no response from exterior water exposure. The observed RBM shift with filling demonstrates a non-monotonic trend with diameter, supporting the assignment of a minimum of 1.81 ± 0.09 cm at 0.93 ± 0.08 nm with a nearly linear increase at larger diameters. We find that a simple hard-sphere model of water in the confined nanotube interior describes key features of the diameter-dependent modulus change of the carbon nanotube and supports previous observations in the literature. Longer segments of 160 μm show partial filling from their ends, consistent with pore clogging. These devices provide an opportunity to study fluid behavior under extreme confinement with high precision and repeatability.
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http://dx.doi.org/10.1021/acsnano.0c08634DOI Listing
February 2021

Combination of Optimization and Metalated-Ligand Exchange: An Effective Approach to Functionalize UiO-66(Zr) MOFs for CO2 Separation.

Chemistry 2015 Nov 19;21(48):17246-55. Epub 2015 Oct 19.

Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585 (Singapore).

The strategy to functionalize water-stable metal-organic frameworks (MOFs) in order to improve their CO2 uptake capacities for efficient CO2 separation remains limited and challenging. We herein present an effective approach to functionalize a prominent water-stable MOF, UiO-66(Zr), by a combination of optimization and metalated-ligand exchange. In particular, by systematic optimization, we have successfully obtained UiO-66(Zr) of the highest BET surface area reported so far (1730 m(2)  g(-1) ). Moreover, it shows a hybrid Type I/IV N2 isotherm at 77 K and a mesopore size of 3.9 nm for the first time. The UiO-66 MOF underwent a metalated-ligand-exchange (MLE) process to yield a series of new UiO-66-type MOFs, among which UiO-66-(COONa)2 -EX and UiO-66-(COOLi)4 -EX MOFs have both enhanced CO2 working capacity and IAST CO2 /N2 selectivity. Our approach has thus suggested an alternative design to achieve water-stable MOFs with high crystallinity and gas uptake for efficient CO2 separation.
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http://dx.doi.org/10.1002/chem.201503078DOI Listing
November 2015

Statistical distance as a measure of physiological dysregulation is largely robust to variation in its biomarker composition.

PLoS One 2015 13;10(4):e0122541. Epub 2015 Apr 13.

Translational Gerontology Branch, Longitudinal Studies Section, National Institute on Aging, National Institutes of Health, MedStar Harbor Hospital, 3001 S. Hanover Street, Baltimore, MD, 21225, United States of America.

Physiological dysregulation may underlie aging and many chronic diseases, but is challenging to quantify because of the complexity of the underlying systems. Recently, we described a measure of physiological dysregulation, DM, that uses statistical distance to assess the degree to which an individual's biomarker profile is normal versus aberrant. However, the sensitivity of DM to details of the calculation method has not yet been systematically assessed. In particular, the number and choice of biomarkers and the definition of the reference population (RP, the population used to define a "normal" profile) may be important. Here, we address this question by validating the method on 44 common clinical biomarkers from three longitudinal cohort studies and one cross-sectional survey. DMs calculated on different biomarker subsets show that while the signal of physiological dysregulation increases with the number of biomarkers included, the value of additional markers diminishes as more are added and inclusion of 10-15 is generally sufficient. As long as enough markers are included, individual markers have little effect on the final metric, and even DMs calculated from mutually exclusive groups of markers correlate with each other at r~0.4-0.5. We also used data subsets to generate thousands of combinations of study populations and RPs to address sensitivity to differences in age range, sex, race, data set, sample size, and their interactions. Results were largely consistent (but not identical) regardless of the choice of RP; however, the signal was generally clearer with a younger and healthier RP, and RPs too different from the study population performed poorly. Accordingly, biomarker and RP choice are not particularly important in most cases, but caution should be used across very different populations or for fine-scale analyses. Biologically, the lack of sensitivity to marker choice and better performance of younger, healthier RPs confirm an interpretation of DM physiological dysregulation and as an emergent property of a complex system.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0122541PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4395377PMC
January 2016