scholarly journals Of masks and methylene blue - the use of methylene blue photochemical treatment to decontaminate surgical masks contaminated with a tenacious small non-enveloped norovirus

2021 ◽  
Author(s):  
Constance Wielick ◽  
Allyson Fries ◽  
Lorène Dams ◽  
Ravo Michèle Razafimahefa ◽  
Belinda Heyne ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Light Exposure ◽  
Red Light ◽  
Short Exposure ◽  
Protective Equipment ◽  
Murine Norovirus ◽  
Pandemic Preparedness ◽  
Surgical Masks ◽  
Single Use ◽  
Human Viruses

Background In the context of the SARS-CoV-2 pandemic, reuse of personal protective equipment, specifically that of medical face coverings, has been recommended. The reuse of these typically single-use only items necessitates procedures to inactivate contaminating human respiratory and gastrointestinal pathogens. We previously demonstrated decontamination of surgical masks and respirators contaminated with infectious SARS-CoV-2 and various animal coronaviruses via low concentration- and short exposure methylene blue photochemical treatment (10 uM methylene blue, 30 minutes of 12,500-lux red light or 50,000 lux white light exposure). Methods Here, we describe the adaptation of this protocol to the decontamination of a more resistant, non-enveloped gastrointestinal virus and demonstrate efficient photodynamic inactivation of murine norovirus, a human norovirus surrogate. Results Methylene blue photochemical treatment (100 uM methylene blue, 30 minutes of 12,500-lux red light exposure) of murine norovirus-contaminated masks reduced infectious viral titres by over four orders of magnitude on surgical mask surfaces. Discussion and Conclusions Inactivation of a norovirus, the most difficult to inactivate of the respiratory and gastrointestinal human viruses, can predict the inactivation of any less resistant viral mask contaminant. The protocol developed here thus solidifies the position of methylene blue photochemical decontamination as an important tool in the package of practical pandemic preparedness.

RESEARCH: Dry Heat Processing of Single-Use Respirators and Surgical Masks

2020 ◽  
Vol 54 (6) ◽  
pp. 410-416
Author(s):  
Joyce M. Hansen ◽  
Scott Weiss ◽  
Terra A. Kremer ◽  
Myrelis Aguilar ◽  
Gerald McDonnell
Keyword(s):  
Microbial Contamination ◽  
Healthcare Providers ◽  
High Volume ◽  
Airborne Particles ◽  
Heat Processing ◽  
Protective Equipment ◽  
Healthcare Facilities ◽  
Dry Heat ◽  
Surgical Masks ◽  
Single Use

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged healthcare providers in maintaining the supply of critical personal protective equipment, including single-use respirators and surgical masks. Single-use respirators and surgical masks can reduce risks from the inhalation of airborne particles and microbial contamination. The recent high-volume demand for single-use respirators and surgical masks has resulted in many healthcare facilities considering processing to address critical shortages. The dry heat process of 80°C (176°F) for two hours (120 min) has been confirmed to be an appropriate method for single-use respirator and surgical mask processing.

scholarly journals The use of germicidal ultraviolet light, vaporised hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus

2020 ◽  
Author(s):  
Louisa F Ludwig-Begall ◽  
Constance Wielick ◽  
Lorene Dams ◽  
Hans Nauwynck ◽  
Pierre-Francois Demeuldre ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Uv Irradiation ◽  
Protective Equipment ◽  
Stable Model ◽  
Dry Heat ◽  
Surgical Masks ◽  
Single Use ◽  
Dry Heat Treatment ◽  
Respiratory Coronavirus ◽  
Porcine Respiratory

Background In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use. Aim We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products. Methods Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, UV irradiation, vaporised H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells. Findings UV irradiation, vaporised H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays. Conclusion This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporised H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the FDA policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilisation in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.

scholarly journals Addressing Personal Protective Equipment (PPE) Decontamination: Methylene Blue and Light Inactivates SARS-CoV-2 on N95 Respirators and Medical Masks with Maintenance of Integrity and Fit

2021 ◽  
pp. 1-83
Author(s):  
Thomas Sean Lendvay ◽  
James Chen ◽  
Brian H Harcourt ◽  
Florine EM Scholte ◽  
Ying Ling Lin ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Personal Protective Equipment ◽  
Low Cost ◽  
Red Light ◽  
Test Methods ◽  
Clinical Applications ◽  
Protective Equipment ◽  
Virus Inactivation ◽  
Specialized Equipment ◽  
N95 Respirators

Abstract Objective: The coronavirus disease 2019 (COVID-19) pandemic has resulted in shortages of personal protective equipment (PPE) underscoring the urgent need for simple, efficient, and inexpensive methods to decontaminate SARS-CoV-2-exposed masks and respirators. We hypothesized that methylene blue (MB) photochemical treatment, which has various clinical applications, could decontaminate PPE contaminated with coronavirus. Design: The two arms of the study included: 1) PPE inoculation with coronaviruses followed by MB with light (MBL) decontamination treatment, and 2) PPE treatment with MBL for 5 cycles of decontamination (5CD) to determine maintenance of PPE performance. Methods: MBL treatment was used to inactivate coronaviruses on three N95 filtering facepiece respirator (FFR) and two medical mask (MM) models. We inoculated FFR and MM materials with three coronaviruses, including SARS-CoV-2, and treated with 10 µM MB and exposed to 50,000 lux of white light or 12,500 lux of red light for 30 minutes. In parallel, integrity was assessed after 5CD using multiple US and international test methods and compared to the FDA-authorized vaporized hydrogen peroxide plus ozone (VHP+O3) decontamination method. Results: Overall, MBL robustly and consistently inactivated all three coronaviruses with 99.8 - to >99.9% virus inactivation across all FFRs and MMs tested. FFR and MM integrity was maintained after 5 cycles of MBL treatment, whereas one FFR model failed after 5 cycles of VHP+O3. Conclusions: MBL treatment decontaminated respirators and masks by inactivating three tested coronaviruses without compromising integrity through 5CD. MBL decontamination is effective, low-cost and does not require specialized equipment, making it applicable in all-resource settings.

scholarly journals Silk fabric as a protective barrier for personal protective equipment and as a functional material for face coverings during the COVID-19 pandemic

2020 ◽  
Author(s):  
Adam F. Parlin ◽  
Samuel M. Stratton ◽  
Theresa M. Culley ◽  
Patrick A. Guerra
Keyword(s):  
Protective Equipment ◽  
Silk Fabric ◽  
Functional Material ◽  
Protective Barrier ◽  
Hydrophobic Barrier ◽  
Surgical Masks ◽  
Single Use ◽  
Do It Yourself ◽  
Clinical Conditions ◽  
N95 Respirators

AbstractBackgroundThe worldwide shortage of single-use N95 respirators and surgical masks due to the COVID-19 pandemic has forced many health care personnel to prolong the use of their existing equipment as much as possible. In many cases, workers cover respirators with available masks in an attempt to extend their effectiveness against the virus. Due to low mask supplies, many people instead are using face coverings improvised from common fabrics. Our goal was to determine what fabrics would be most effective in both practices.Methods and findingsWe examined the hydrophobicity of fabrics (silk, cotton, polyester), as measured by their resistance to the penetration of small and aerosolized water droplets, an important transmission avenue for the virus causing COVID-19. We also examined the breathability of these fabrics and their ability to maintain hydrophobicity despite undergoing repeated cleaning. Tests were done when fabrics were fashioned as an overlaying barrier and also when constructed as do-it-yourself face coverings. As a protective barrier and face covering, silk is more effective at impeding the penetration and absorption of droplets due to its greater hydrophobicity relative to other tested fabrics. Silk face coverings repelled droplets as well as masks, but unlike masks they are hydrophobic and can be readily sterilized for immediate reuse.ConclusionsSilk is an effective hydrophobic barrier to droplets, more breathable than other fabrics that trap humidity, and are readily re-useable via cleaning. Therefore, silk can serve as an effective material for protecting respirators under clinical conditions and as a material for face coverings.

scholarly journals DECONTAMINATION INTERVENTIONS FOR THE REUSE OF SURGICAL MASK PERSONAL PROTECTIVE EQUIPMENT (PPE): A PROTOCOL FOR A SYSTEMATIC REVIEW

2020 ◽  
Author(s):  
David Zorko ◽  
Karen Choong ◽  
Dayre McNally ◽  
Katie O'Hearn ◽  
Margaret Sampson ◽  
...  
Keyword(s):  
Systematic Review ◽  
Hydrogen Peroxide ◽  
Personal Protective Equipment ◽  
Protective Equipment ◽  
High Demand ◽  
Ultraviolet Germicidal Irradiation ◽  
Surgical Masks ◽  
Global Spread ◽  
Single Use ◽  
Novel Coronavirus

As the global spread of novel coronavirus (SARS-CoV-2) escalates, the high demand for personal protective equipment (PPE) has created shortages of this equipment globally and prompted the need to ensure appropriate stewardship and develop strategies to conserve supply. Surgical masks have broad and commonplace applications as PPE, including in the care of suspected or confirmed COVID-19 patients, and for the care of the general patient population in areas where community spread of COVID-19 is of concern. Surgical mask rationing and conservation is therefore a priority to ensure adequate supply during a pandemic. Several methods have been considered to decontaminate and allow the reuse of single-use PPE, such as hydrogen peroxide vapour and ultraviolet germicidal irradiation, but to date this literature has not been comprehensively synthesized. The objective of this systematic review is to identify and synthesize data from published studies evaluating interventions used to decontaminate or treat surgical mask PPE for the purposes of reuse.

scholarly journals ECO-DESIGN ACTIONS TO IMPROVE LIFE CYCLE ENVIRONMENTAL PERFORMANCE OF FACE MASKS IN THE PANDEMIC ERA

2021 ◽  
Vol 1 ◽  
pp. 1333-1342
Author(s):  
Núria Boix Rodríguez ◽  
Marco Marconi ◽  
Claudio Favi ◽  
Giovanni Formentini
Keyword(s):  
Life Cycle ◽  
Environmental Performance ◽  
Climate Changes ◽  
Environmental Problem ◽  
Negative Impact ◽  
Environmental Issues ◽  
Design Guidelines ◽  
Protective Equipment ◽  
Single Use ◽  
Near Future

AbstractFace masks are currently considered essential devices that people must wear today and in the near future, until the COVID-19 pandemic will be completely defeated through specific medicines and vaccines. Such devices are generally made of thermoplastic polymers, as polypropylene and polyethylene and are single use products. Even if in this period the sanitary emergency must have the maximum priority, the world society should not completely forget the environmental problem that are causing more and more obvious climate changes with correlated damages to ecosystems and human health. Despite the well-known correlation among anti-COVID protective equipment (or more generally medical devices) and environmental issues, the Life Cycle Assessment (LCA) and eco-design-based studies in this field is very scarce. The present study aims to derive the most important environmental criticalities of such products, by using LCA and product circularity indicators of five different common masks. The final aim is to provide eco-design guidelines, useful to design new face masks by preventing negative impact on the environment.

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

scholarly journals Ultraviolet-C as a Viable Reprocessing Method for Disposable Masks and Filtering Facepiece Respirators

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 801
Author(s):  
Talita Nicolau ◽  
Núbio Gomes Filho ◽  
Andrea Zille
Keyword(s):  
Literature Review ◽  
Systematic Literature Review ◽  
Personal Protective Equipment ◽  
State Of The Art ◽  
Protective Equipment ◽  
Multiple Methods ◽  
Ultraviolet C ◽  
Single Use ◽  
Uv C ◽  
New Strategies

In normal conditions, discarding single-use personal protective equipment after use is the rule for its users due to the possibility of being infected, particularly for masks and filtering facepiece respirators. When the demand for these protective tools is not satisfied by the companies supplying them, a scenario of shortages occurs, and new strategies must arise. One possible approach regards the disinfection of these pieces of equipment, but there are multiple methods. Analyzing these methods, Ultraviolet-C (UV-C) becomes an exciting option, given its germicidal capability. This paper aims to describe the state-of-the-art for UV-C sterilization in masks and filtering facepiece respirators. To achieve this goal, we adopted a systematic literature review in multiple databases added to a snowball method to make our sample as robust as possible and encompass a more significant number of studies. We found that UV-C’s germicidal capability is just as good as other sterilization methods. Combining this characteristic with other advantages makes UV-C sterilization desirable compared to other methods, despite its possible disadvantages.

Use of A GAS Jet Technique to Prepare Microcrystalline Silicon Based Solar Cells at High I-Layer Deposition Rates

1999 ◽  
Vol 557 ◽  
Author(s):  
S.J. Jones ◽  
R. Crucet ◽  
X. Deng ◽  
J. Doehler ◽  
R. Kopf ◽  
...  
Keyword(s):  
Solar Cells ◽  
Peak Power ◽  
Light Exposure ◽  
Red Light ◽  
Gas Jet ◽  
Scale Production ◽  
Microcrystalline Silicon ◽  
Deposition Rates ◽  
Layer Deposition ◽  
Power Outputs

AbstractUsing a Gas Jet thin film deposition technique, microcrystalline silicon (μc-Si) materials were prepared at rates as high as 15-20 Å/s. The technique involves the use of a gas jet flow that is subjected to a high intensity microwave source. The quality of the material has been optimized through the variation of a number of deposition conditions including the substrate temperature, the gas flows, and the applied microwave power. The best films were made using deposition rates near 16 Å/s. These materials have been used as i-layers for red light absorbing, nip single-junction solar cells. Using a 610nm cutoff filter which only allows red light to strike the device, pre-light soaked currents as high as 10 mA/cm2 and 2.2-2.3% red-light pre-light soaked peak power outputs have been obtained for cells with i-layer thicknesses near 1 micron. This compares with currents of 10-11 mA/cm2 and 4% initial red-light peak power outputs obtained for high efficiency amorphous silicon germanium alloy (a-SiGe:H) devices. The AM1.5 white light efficiencies for these microcrystalline cells are 5.9-6.0%. While the efficiencies for the a-SiGe:H cells degrade by 15-20% after long term light exposure, the efficiencies for the microcrystalline cells before and after prolonged light exposure are similar, within measurement error. Considering these results, the Gas Jet deposition method is a promising technique for the deposition of μc-Si solar cells due to the ability to achieve reasonable stable efficiencies for cells at i-layer deposition rates (16 Å/s) which make large-scale production economically feasible.

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