scholarly journals Elastomeric Harnesses Decrease Aerosol Particles Leak and Improve the Fit of Surgical Masks

2021 ◽  
Author(s):  
Jeannette Ingabire ◽  
Hannah McKenney ◽  
Charles Sebesta ◽  
Krishna Badhiwala ◽  
Ben Avants ◽  
...  
Keyword(s):  
Large Scale ◽  
Hospital Setting ◽  
Ir Imaging ◽  
Surgical Masks ◽  
Human Volunteers ◽  
Close Proximity ◽  
Fit Testing ◽  
The Face ◽  
Set Up ◽  
N95 Respirators

ABSTRACTImportanceThe outbreak of Coronavirus diseases 2019 (COVID-19) disease has increased demand for N95 respirators, surgical masks, and other facial coverings to stop the spread of SARS-CoV-2. Research shows that N95 respirators perform the best at filtering viral droplets and aerosols, however these masks are much more difficult to manufacture and expensive to distribute on a large scale, which led to shortages during the pandemic. Surgical masks, on the other hand, were more widely available and have been previously used to mitigate the spread of tuberculosis and influenza.ObjectivesTo evaluate the filter filtration efficiency (FFE) of three elastomeric harness designs in hospital and research settings in order to improve facemask seal.Design, setting and participantsA multi-institutional collaboration between engineers and health professionals, conducted between November 2020 and March 2021, was set up to design an elastomeric harness to improve the face seal of a surgical mask. Three elastomeric harness designs were created with harness designs 1 and 2 tested in a research laboratory setting and harness design 2.1 tested in a hospital setting. The initial harness design 1 was laser cut for testing and design 2 was developed to improve the detected particle leakage around the nose bridge area by introducing more material in that region. Design 2.1 is developed for hospital settings with less material around the nose bridge to reduce vision disruption. The designs were tested on mannequins and human volunteers using IR imaging and standard fit testing equipment.Main Outcomes and MeasuresOur elastomeric harness can improve the seal of a surgical mask allowing it to pass the fit test used to evaluate N95 respirators. 24/39 participants achieved a passing score of 100 or more while wearing the second harness design. IR imaging determined that the nasal sidewalls region of the mask is most prone to leakage when using our first elastomeric harness.Conclusions and RelevanceOverall, these results confirm that elastomeric harnesses combined with surgical masks improve their ability to filter aerosolized particles, which is especially important when in close proximity to individuals who are infectious or while performing aerosol-generating medical procedures.

scholarly journals Use, reuse or discard: quantitatively defined variance in N95 respirator integrity following vaporized hydrogen peroxide decontamination during the COVID-19 pandemic

2020 ◽  
Author(s):  
Carly Levine ◽  
Courtney Grady ◽  
Thomas Block ◽  
Harry Hurley ◽  
Riccardo Russo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Comprehensive Evaluation ◽  
Hospital Setting ◽  
Protective Equipment ◽  
Potential Solution ◽  
Face Shape ◽  
Testing Method ◽  
Fit Testing ◽  
The Face ◽  
N95 Respirators

Background: COVID-19 has stretched the ability of many institutions to supply needed personal protective equipment, especially N95 respirators. N95 decontamination and reuse programs provide one potential solution to this problem. Unfortunately, a comprehensive evaluation of the effects of decontamination on the integrity of various N95 models using a quantitative fit test (QTFT) approach is lacking. Aims: 1) To investigate the effects of up to eight rounds of vaporized H2O2 (VHP) decontamination on the integrity of N95 respirators currently in use in a hospital setting. 2) To examine if N95 respirators worn by one user can adapt to the face shape of a second user with no compromise of integrity following VHP decontamination. Methods: The PortaCount Pro+ Respirator Fit Tester Model 8038 was used to quantitatively define the integrity, measured by fit, of N95 respirators following decontamination with VHP. Findings: There was an observable downward trend in the integrity of Halyard Fluidshield 46727 N95 respirators throughout eight cycles of decontamination with VHP. The integrity of 3M 1870 N95 respirators was significantly reduced after the respirator was worn, decontaminated with VHP, and then quantitatively fit tested on a second user. Furthermore, we uncovered inconsistencies between qualitative fit test and QTFT results that may have strong implications on the fit testing method used by institutions. Conclusions: Our data revealed variability in the integrity of different N95 models after VHP decontamination and exposed potential limitations of N95 decontamination and reuse programs.

scholarly journals Applying heat and humidity using stove boiled water for decontamination of N95 respirators in low resource settings

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255338
Author(s):  
Siddharth Doshi ◽  
Samhita P. Banavar ◽  
Eliott Flaum ◽  
Surendra Kulkarni ◽  
Ulhas Vaidya ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Low Resource Settings ◽  
Low Resource ◽  
Surgical Masks ◽  
Temperature And Humidity ◽  
Similar Temperature ◽  
N95 Respirators ◽  
Electricity Access ◽  
Uv C

Global shortages of N95 respirators have led to an urgent need of N95 decontamination and reuse methods that are scientifically validated and available world-wide. Although several large scale decontamination methods have been proposed (hydrogen peroxide vapor, UV-C); many of them are not applicable in remote and low-resource settings. Heat with humidity has been demonstrated as a promising decontamination approach, but care must be taken when implementing this method at a grassroots level. Here we present a simple, scalable method to provide controlled humidity and temperature for individual N95 respirators which is easily applicable in low-resource settings. N95 respirators were subjected to moist heat (>50% relative humidity, 65–80°C temperature) for over 30 minutes by placing them in a sealed container immersed in water that had been brought to a rolling boil and removed from heat, and then allowing the containers to sit for over 45 minutes. Filtration efficiency of 0.3–4.99 μm incense particles remained above 97% after 5 treatment cycles across all particle size sub-ranges. This method was then repeated at a higher ambient temperature and humidity in Mumbai, using standard utensils commonly found in South Asia. Similar temperature and humidity profiles were achieved with no degradation in filtration efficiencies after 6 cycles. Higher temperatures (>70°C) and longer treatment times (>40 minutes) were obtained by insulating the outer vessel. We also showed that the same method can be applied for the decontamination of surgical masks. This simple yet reliable method can be performed even without electricity access using any heat source to boil water, from open-flame stoves to solar heating, and provides a low-cost route for N95 decontamination globally applicable in resource-constrained settings.

scholarly journals A Customized Mask Retainer and Its Effects on Improving the Fit Performance of Surgical Masks

2021 ◽  
Author(s):  
Xi Chen ◽  
Qi Xi ◽  
Wei Lu ◽  
Fangfang Sun ◽  
Lirong Wang ◽  
...  
Keyword(s):  
Fold Increase ◽  
Face Mask ◽  
Matched Pairs ◽  
3D Face ◽  
Surgical Masks ◽  
The Face ◽  
3D Printed ◽  
Scan Data ◽  
N95 Respirators ◽  
Chinese Standard

Abstract Background: With the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the effectiveness of providing mask protection is important for people. This article introduces a customized mask retainer to improve the fit performance of face masks.Methods: The participant’s 3D face scans with and without a surgical mask were taken by using a 3D face scanner. The fitter was designed on the 3D face scan data according to the facial anthropometric landmarks, and examined and adjusted on the face scan data with a mask. The fitter was 3D printed using a metal printer for Titanium. The effectiveness of the fitter on augmentation of fit of surgical mask was test according to the Chinese Standard. Tests were repeated three times per participant, and compare differences between groups by Wilcoxon Matched-Pairs Signed-Ranks Test using software (a=.05).Results: The effectiveness test of the retainer on augmentation of fit performance showed a result more than 25-fold increase of overall Fit Factor, which have met the fit requirement for KN95 respirators in China.Conclusions: Fit Factor results indicated that by using the retainer, the Fit Factors of overall and each exercise have significantly increased as compared to that of face mask alone group. It may provide a solution to the shortage of N95 respirators the world is now encountering as fighting against the COVID-19 epidemic.

scholarly journals Decontaminating N95 respirators during the Covid-19 pandemic: simple and practical approaches to increase decontamination capacity, speed, safety and ease of use.

2020 ◽  
Author(s):  
RICCARDO RUSSO ◽  
Carly Levine ◽  
Courtney Veilleux ◽  
Blas Peixoto ◽  
Jessica McCormick-Ell ◽  
...  
Keyword(s):  
Large Scale ◽  
Ease Of Use ◽  
Chemical Indicators ◽  
Hands On ◽  
Level 3 ◽  
Set Up ◽  
N95 Respirators ◽  
Severe Shortage ◽  
Facility Capacity ◽  
Biosafety Level

Background: The COVID-19 pandemic has caused a severe shortage of personal protective equipment (PPE), especially N95 respirators. Efficient, effective and economically feasible methods for large-scale PPE decontamination are urgently needed. Aims: (1) to develop protocols for effectively decontaminating PPE using vaporized hydrogen peroxide (VHP); (2) to develop novel approaches that decrease set up and take down time while also increasing decontamination capacity (3) to test decontamination efficiency for N95 respirators heavily contaminated by makeup or moisturizers. Methods: We converted a decommissioned Biosafety Level 3 laboratory into a facility that could be used to decontaminate N95 respirators. N95 respirators were hung on metal racks, stacked in piles, placed in paper bags or covered with makeup or moisturizer. A VHP VICTORYTM unit from STERIS was used to inject VHP into the facility. Biological and chemical indicators were used to validate the decontamination process. Findings: N95 respirators individually hung on metal racks were successfully decontaminated using VHP. N95 respirators were also successfully decontaminated when placed in closed paper bags or if stacked in piles of up to six. Stacking reduced the time needed to arrange N95 respirators for decontamination by approximately two-thirds while almost tripling facility capacity. Makeup and moisturizer creams did not interfere with the decontamination process. Conclusions: Respirator stacking can reduce the hands-on time and increase decontamination capacity. When personalization is needed, respirators can be decontaminated in labeled paper bags. Make up or moisturizers do not appear to interfere with VHP decontamination.

Platelet Anti-Aggregating Activity and Tolerance of Clopidogrel in Atherosclerotic Patients

1996 ◽  
Vol 76 (06) ◽  
pp. 0939-0943 ◽  
Author(s):  
B Boneu ◽  
G Destelle ◽  
Keyword(s):  
Platelet Aggregation ◽  
Large Scale ◽  
Bleeding Time ◽  
Antithrombotic Activity ◽  
Ambulatory Patients ◽  
Patients At Risk ◽  
Set Up ◽  
Ischemic Events ◽  
Large Scale Clinical Trial ◽  
Selection Of

SummaryThe anti-aggregating activity of five rising doses of clopidogrel has been compared to that of ticlopidine in atherosclerotic patients. The aim of this study was to determine the dose of clopidogrel which should be tested in a large scale clinical trial of secondary prevention of ischemic events in patients suffering from vascular manifestations of atherosclerosis [CAPRIE (Clopidogrel vs Aspirin in Patients at Risk of Ischemic Events) trial]. A multicenter study involving 9 haematological laboratories and 29 clinical centers was set up. One hundred and fifty ambulatory patients were randomized into one of the seven following groups: clopidogrel at doses of 10, 25, 50,75 or 100 mg OD, ticlopidine 250 mg BID or placebo. ADP and collagen-induced platelet aggregation tests were performed before starting treatment and after 7 and 28 days. Bleeding time was performed on days 0 and 28. Patients were seen on days 0, 7 and 28 to check the clinical and biological tolerability of the treatment. Clopidogrel exerted a dose-related inhibition of ADP-induced platelet aggregation and bleeding time prolongation. In the presence of ADP (5 \lM) this inhibition ranged between 29% and 44% in comparison to pretreatment values. The bleeding times were prolonged by 1.5 to 1.7 times. These effects were non significantly different from those produced by ticlopidine. The clinical tolerability was good or fair in 97.5% of the patients. No haematological adverse events were recorded. These results allowed the selection of 75 mg once a day to evaluate and compare the antithrombotic activity of clopidogrel to that of aspirin in the CAPRIE trial.

Interpreting Seventeenth-Century Probate Documents: John Carter, Master Carpenter in St Albans

2011 ◽  
pp. 66-83
Author(s):  
Jane Harris ◽  
Pat Howe
Keyword(s):  
Seventeenth Century ◽  
Large Scale ◽  
Local Context ◽  
Social Standing ◽  
Close Proximity ◽  
Market Town ◽  
Consumer Age

This is a study of a successful seventeenth-century carpenter in St Albans, John Carter, using probate and other documents, assisted by a large-scale computer database of St Albans residents of the period. Sections of the article cover his family, his work and his house and its contents, which have been reconstructed from his probate inventory and from knowledge of the structure of other local houses of the period. Carter's social standing is discussed, both in its local context and in relation to previous probate inventory analyses. This micro-study sheds unusual light upon aspects of the life of a 'middling sort' of person, living in a thriving market town in close proximity to London, at the beginning of the consumer age.

MODELING THE SOUTH ATLANTIC OCEAN FROM MEDIUM TO HIGH RESOLUTION

2014 ◽  
Vol 31 (2) ◽  
Author(s):  
Mariela Gabioux ◽  
Vladimir Santos da Costa ◽  
Joao Marcos Azevedo Correia de Souza ◽  
Bruna Faria de Oliveira ◽  
Afonso De Moraes Paiva
Keyword(s):  
High Resolution ◽  
Atlantic Ocean ◽  
Large Scale ◽  
South Atlantic ◽  
Surface Relaxation ◽  
The South ◽  
Small Surface ◽  
Basic Model ◽  
Basic Set ◽  
Set Up

Results of the basic model configuration of the REMO project, a Brazilian approach towards operational oceanography, are discussed. This configuration consists basically of a high-resolution eddy-resolving, 1/12 degree model for the Metarea V, nested in a medium-resolution eddy-permitting, 1/4 degree model of the Atlantic Ocean. These simulations performed with HYCOM model, aim for: a) creating a basic set-up for implementation of assimilation techniques leading to ocean prediction; b) the development of hydrodynamics bases for environmental studies; c) providing boundary conditions for regional domains with increased resolution. The 1/4 degree simulation was able to simulate realistic equatorial and south Atlantic large scale circulation, both the wind-driven and the thermohaline components. The high resolution simulation was able to generate mesoscale and represent well the variability pattern within the Metarea V domain. The BC mean transport values were well represented in the southwestern region (between Vitória-Trinidade sea mount and 29S), in contrast to higher latitudes (higher than 30S) where it was slightly underestimated. Important issues for the simulation of the South Atlantic with high resolution are discussed, like the ideal place for boundaries, improvements in the bathymetric representation and the control of bias SST, by the introducing of a small surface relaxation. In order to make a preliminary assessment of the model behavior when submitted to data assimilation, the Cooper & Haines (1996) method was used to extrapolate SSH anomalies fields to deeper layers every 7 days, with encouraging results.

Ban Ki-moon, 2007–2016

2018 ◽  
Author(s):  
Richard Gowan
Keyword(s):  
United States ◽  
Decision Making ◽  
Security Council ◽  
Large Scale ◽  
Central African Republic ◽  
The United States ◽  
Cautious Approach ◽  
Peacekeeping Operations ◽  
Council Decision ◽  
The Face

During Ban Ki-moon’s tenure, the Security Council was shaken by P5 divisions over Kosovo, Georgia, Libya, Syria, and Ukraine. Yet it also continued to mandate and sustain large-scale peacekeeping operations in Africa, placing major burdens on the UN Secretariat. The chapter will argue that Ban initially took a cautious approach to controversies with the Council, and earned a reputation for excessive passivity in the face of crisis and deference to the United States. The second half of the chapter suggests that Ban shifted to a more activist pressure as his tenure went on, pressing the Council to act in cases including Côte d’Ivoire, Libya, and Syria. The chapter will argue that Ban had only a marginal impact on Council decision-making, even though he made a creditable effort to speak truth to power over cases such as the Central African Republic (CAR), challenging Council members to live up to their responsibilities.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

scholarly journals Environmental Engineering Techniques to Restore Degraded Posidonia oceanica Meadows

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 661
Author(s):  
Luigi Piazzi ◽  
Stefano Acunto ◽  
Francesca Frau ◽  
Fabrizio Atzori ◽  
Maria Francesca Cinti ◽  
...  
Keyword(s):  
Large Scale ◽  
Natural Habitat ◽  
Cost Benefit ◽  
Cost Effective ◽  
Posidonia Oceanica ◽  
Environmental Engineering ◽  
Bottom Surface ◽  
Sessile Invertebrates ◽  
Set Up ◽  
Short Time

Seagrass planting techniques have shown to be an effective tool for restoring degraded meadows and ecosystem function. In the Mediterranean Sea, most restoration efforts have been addressed to the endemic seagrass Posidonia oceanica, but cost-benefit analyses have shown unpromising results. This study aimed at evaluating the effectiveness of environmental engineering techniques generally employed in terrestrial systems to restore the P. oceanica meadows: two different restoration efforts were considered, either exploring non-degradable mats or, for the first time, degradable mats. Both of them provided encouraging results, as the loss of transplanting plots was null or very low and the survival of cuttings stabilized to about 50%. Data collected are to be considered positive as the survived cuttings are enough to allow the future spread of the patches. The utilized techniques provided a cost-effective restoration tool likely affordable for large-scale projects, as the methods allowed to set up a wide bottom surface to restore in a relatively short time without any particular expensive device. Moreover, the mats, comparing with other anchoring methods, enhanced the colonization of other organisms such as macroalgae and sessile invertebrates, contributing to generate a natural habitat.

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