The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Costantino Balestra - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Protection Level respiratory safety and practical aspects of commercially available snorkel masks as personal Protection devices against aerosolized contaminants and sars cov2
International Journal of Environmental Research and Public Health, 2020Co-Authors: Peter Germonpre, Dirk Van Rompaey, Costantino BalestraAbstract:Introduction: The "Severe Acute Respiratory Syndrome Coronavirus 2″ (SARS-CoV2) pandemic has led to a worldwide shortage of personal Protection devices (PPD) for medical and paramedical personnel. Adaptation of commercially available snorkel masks to serve as full face masks has been proposed. Even not formally approved as PPD, they are publicized on social media as suitable for this use. Concerns about actual Protection Levels and risk of carbon dioxide (CO2) accumulation while wearing them for extended periods made us perform a systematic testing of various brands, in order to verify whether they are as safe and effective as claimed. Methods: A 'fit' test was performed, analogous to gas mask testing. Respiratory safety was evaluated by measuring end-tidal CO2 and oxygen saturation while wearing the masks in rest and during physical exercise. Masks were tested with 3D adaptors to mount regular bacterial-viral ventilator filters when available, or with snorkel openings covered with N95/FFP2 cloth. Results: Modified masks performed reasonably well on the fit test, comparable to regular N95/FFP2 masks. Not all ventilator filters are equally protective. For all masks, a small initial increase in end-tidal CO2 was noted, remaining within physiological limits. 3D printed adaptors are safer, have more flexibility and reliability than makeshift adaptations. Conclusions: These masks can offer benefit as a substitute for complete protective gear as they are easier to don and remove and offer full-face Protection. They may be more comfortable to wear for extended periods. Proper selection of mask size, fit testing, quality of 3D printed parts, and choice of filter are important.
Anna Balazy - One of the best experts on this subject based on the ideXlab platform.
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do n95 respirators provide 95 Protection Level against airborne viruses and how adequate are surgical masks
American Journal of Infection Control, 2006Co-Authors: Tiina Reponen, Anna Balazy, Mika Toivola, Atin Adhikari, Satheesh K Sivasubramani, Sergey A. GrinshpunAbstract:Background Respiratory Protection devices are used to protect the wearers from inhaling particles suspended in the air. Filtering face piece respirators are usually tested utilizing nonbiologic particles, whereas their use often aims at reducing exposure to biologic aerosols, including infectious agents such as viruses and bacteria. Methods The performance of 2 types of N95 half-mask, filtering face piece respirators and 2 types of surgical masks were determined. The collection efficiency of these respiratory Protection devices was investigated using MS2 virus (a nonharmful simulant of several pathogens). The virions were detected in the particle size range of 10 to 80 nm. Results The results indicate that the penetration of virions through the National Institute for Occupational Safety and Health (NIOSH)-certified N95 respirators can exceed an expected Level of 5%. As anticipated, the tested surgical masks showed a much higher particle penetration because they are known to be less efficient than the N95 respirators. The 2 surgical masks, which originated from the same manufacturer, showed tremendously different penetration Levels of the MS2 virions: 20.5% and 84.5%, respectively, at an inhalation flow rate of 85 L/min. Conclusion The N95 filtering face piece respirators may not provide the expected Protection Level against small virions. Some surgical masks may let a significant fraction of airborne viruses penetrate through their filters, providing very low Protection against aerosolized infectious agents in the size range of 10 to 80 nm. It should be noted that the surgical masks are primarily designed to protect the environment from the wearer, whereas the respirators are supposed to protect the wearer from the environment.
Sergey A. Grinshpun - One of the best experts on this subject based on the ideXlab platform.
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performance of an n95 filtering facepiece particulate respirator and a surgical mask during human breathing two pathways for particle penetration
Journal of Occupational and Environmental Hygiene, 2009Co-Authors: Sergey A. Grinshpun, Hiroki Haruta, Robert M Eninger, Tiina Reponen, Roy T Mckay, Shuan LeeAbstract:The Protection Level offered by filtering facepiece particulate respirators and face masks is defined by the percentage of ambient particles penetrating inside the Protection device. There are two penetration pathways: (1) through the faceseal leakage, and the (2) filter medium. This study aimed at differentiating the contributions of these two pathways for particles in the size range of 0.03–1 μm under actual breathing conditions. One N95 filtering facepiece respirator and one surgical mask commonly used in health care environments were tested on 25 subjects (matching the latest National Institute for Occupational Safety and Health fit testing panel) as the subjects performed conventional fit test exercises. The respirator and the mask were also tested with breathing manikins that precisely mimicked the prerecorded breathing patterns of the tested subjects. The penetration data obtained in the human subject- and manikin-based tests were compared for different particle sizes and breathing patterns. Overal...
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do n95 respirators provide 95 Protection Level against airborne viruses and how adequate are surgical masks
American Journal of Infection Control, 2006Co-Authors: Tiina Reponen, Anna Balazy, Mika Toivola, Atin Adhikari, Satheesh K Sivasubramani, Sergey A. GrinshpunAbstract:Background Respiratory Protection devices are used to protect the wearers from inhaling particles suspended in the air. Filtering face piece respirators are usually tested utilizing nonbiologic particles, whereas their use often aims at reducing exposure to biologic aerosols, including infectious agents such as viruses and bacteria. Methods The performance of 2 types of N95 half-mask, filtering face piece respirators and 2 types of surgical masks were determined. The collection efficiency of these respiratory Protection devices was investigated using MS2 virus (a nonharmful simulant of several pathogens). The virions were detected in the particle size range of 10 to 80 nm. Results The results indicate that the penetration of virions through the National Institute for Occupational Safety and Health (NIOSH)-certified N95 respirators can exceed an expected Level of 5%. As anticipated, the tested surgical masks showed a much higher particle penetration because they are known to be less efficient than the N95 respirators. The 2 surgical masks, which originated from the same manufacturer, showed tremendously different penetration Levels of the MS2 virions: 20.5% and 84.5%, respectively, at an inhalation flow rate of 85 L/min. Conclusion The N95 filtering face piece respirators may not provide the expected Protection Level against small virions. Some surgical masks may let a significant fraction of airborne viruses penetrate through their filters, providing very low Protection against aerosolized infectious agents in the size range of 10 to 80 nm. It should be noted that the surgical masks are primarily designed to protect the environment from the wearer, whereas the respirators are supposed to protect the wearer from the environment.
Kai Li - One of the best experts on this subject based on the ideXlab platform.
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virtual memory primitives for user programs
Architectural Support for Programming Languages and Operating Systems, 1991Co-Authors: Andrew W. Appel, Kai LiAbstract:Memory Management Units (MMUs) are traditionally used by operating systems to implement disk-paged virtual memory. Some operating systems allow user programs to specify the Protection Level (inaccessible, readonly, read-write) of pages, and allow user programs to handle Protection violations, but these mechanisms are not always robust, e cient, or well-matched to the needs of applications. We survey several user-Level algorithms that make use of page-Protection techniques, and analyze their common characteristics, in an attempt to answer the question, \What virtual-memory primitives should the operating system provide to user processes, and how well do today's operating systems provide them?"
Peter Germonpre - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Protection Level respiratory safety and practical aspects of commercially available snorkel masks as personal Protection devices against aerosolized contaminants and sars cov2
International Journal of Environmental Research and Public Health, 2020Co-Authors: Peter Germonpre, Dirk Van Rompaey, Costantino BalestraAbstract:Introduction: The "Severe Acute Respiratory Syndrome Coronavirus 2″ (SARS-CoV2) pandemic has led to a worldwide shortage of personal Protection devices (PPD) for medical and paramedical personnel. Adaptation of commercially available snorkel masks to serve as full face masks has been proposed. Even not formally approved as PPD, they are publicized on social media as suitable for this use. Concerns about actual Protection Levels and risk of carbon dioxide (CO2) accumulation while wearing them for extended periods made us perform a systematic testing of various brands, in order to verify whether they are as safe and effective as claimed. Methods: A 'fit' test was performed, analogous to gas mask testing. Respiratory safety was evaluated by measuring end-tidal CO2 and oxygen saturation while wearing the masks in rest and during physical exercise. Masks were tested with 3D adaptors to mount regular bacterial-viral ventilator filters when available, or with snorkel openings covered with N95/FFP2 cloth. Results: Modified masks performed reasonably well on the fit test, comparable to regular N95/FFP2 masks. Not all ventilator filters are equally protective. For all masks, a small initial increase in end-tidal CO2 was noted, remaining within physiological limits. 3D printed adaptors are safer, have more flexibility and reliability than makeshift adaptations. Conclusions: These masks can offer benefit as a substitute for complete protective gear as they are easier to don and remove and offer full-face Protection. They may be more comfortable to wear for extended periods. Proper selection of mask size, fit testing, quality of 3D printed parts, and choice of filter are important.
