Face Mask Technologies

This forum is to discuss general things concerning TSOI.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

California recalls more than 10 million N95 masks

9/18/20

https://www.cnn.com/world/live-news/cor ... index.html

More than 10 million N95 masks purchased using a $90 million contract are being recalled by the state of California, according to Brian Ferguson, spokesperson for the Governor's Office of Emergency Services (Cal OES).

The state was notified on Sept. 11 that the National Institute for Occupational Safety and Health (NIOSH) had withdrawn its temporary certification of N95 masks made by the Santa Clara-based company Advoque Safeguard and immediately began recalling them, Ferguson told CNN.

According to Ferguson, 10.2 million of these masks have been received and 7.2 million of those had been distributed as of Sept. 8.

The California Department of Public Health (CDPH) notified all recipients of these masks of the change in certification and directed these masks “no longer be used in settings requiring the use of this essential PPE,” Ferguson said.

About the masks: N95 masks, which filters at least 95% of airborne particles, are the most common respirators approved by the Centers for Disease Control and Prevention (CDC). The CDC has recommended N95 masks for essential workers to reduce the risk of exposure to the coronavirus.

Ferguson explained that the NIOSH certification is an explicit requirement of all state contracts for N95 masks to ensure that frontline workers can be confident that the masks meet federal health and safety standards.

“It is a condition of the contract, and is incumbent upon the vendor, to maintain this certification,” he said.

Despite the state’s recall of all N95 masks made by Advoque Safeguard, the company announced in a letter to its customers and distributors on Wednesday that it is not conducting a recall of their masks, but have established a “product replacement program” as a courtesy to their customers.

“NIOSH has not asked us to implement a recall but has requested that we be diligent in informing our customers of the situation, and we are doing so,” Advoque Safeguard co-founder and chief technology officer Jason Azevedo said in a statement to CNN. “Additionally, Advoque Safeguard has instituted an exchange program for N95 respirators.”

The exact reason for the recall is unknown and has not been explained. CNN has reached out to the CDPH and NIOSH for additional details.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Face Masks and Surgical Masks for COVID-19: Manufacturing, Purchasing, Importing, and Donating Masks During the Public Health Emergency

https://www.fda.gov/medical-devices/cor ... sks-during

In general, masks are used by the general public and health care personnel to prevent the spread of infection or illness.

This page is for people and organizations who are new to working with the FDA.
To help expand the availability of face masks and surgical masks, the FDA is providing regulatory flexibility, as described in our policy for face masks and surgical masks that is in effect during the COVID-19 pandemic.

If you are interested in manufacturing these products, we urge you to review:

The FDA’s Emergency Use Authorization (EUA) for face masks (PDF-98KB) (issued April 24, 2020)
The FDA’s policy on face masks and surgical masks that is in effect during the COVID-19 public health emergency
Registration and Listing of Medical Devices During the COVID-19 Pandemic
The information on this page.

You may send any specific questions to CDRH-COVID19-SurgicalMasks@fda.hhs.gov.

Q: Which masks are medical devices regulated by the FDA?

A. Face masks marketed to the general public for general non-medical purposes, such as use in construction and other industrial applications, are not medical devices. Face masks, when they are intended for a medical purpose such as source control (including uses related to COVID-19) and surgical masks are medical devices.
Q: Is there a difference between a mask and a respirator?

A: Masks and respirators both cover a wearer’s nose and mouth, but they differ in several aspects.

Masks are loose fitting and may not provide full protection from breathing in airborne pathogens, such as viruses.

Face masks (non-surgical masks) may not provide protection from fluids or may not filter particles, needed to protect against pathogens, such as viruses. They are not for surgical use and are not considered personal protective equipment.
Surgical masks are fluid-resistant, disposable, and loose-fitting devices that create a physical barrier between the mouth and nose of the wearer and the immediate environment. They are for use in surgical settings and do not provide full protection from inhalation of airborne pathogens, such as viruses.

Respirators are personal protective equipment that tightly fit the face and filter airborne particles to protect health care workers. They provide a higher level of protection against viruses and bacteria when properly fit-tested. This document does not address respirators.

This CDC infographic explains the differences between surgical masks and N95 respirators.
Q: I am interested in manufacturing face masks for COVID-19. What do I need to do?

A: It will depend on the type of mask you want to manufacture.

Masks for non-medical purposes are not medical devices and are not regulated by the FDA.

The FDA has issued an EUA for face masks that meet certain criteria, including cloth face coverings recommended by the Centers for Disease Control (CDC). During the COVID-19 public health emergency, a face mask for a medical purpose that is intended for use as source control, is not labeled as a surgical mask, and is not intended to provide liquid barrier protection, may be authorized under the "umbrella" EUA for face masks without submitting documentation to the FDA if the face mask meets the eligibility requirements. A face mask authorized under this EUA must comply with the Conditions of Authorization (Section IV) of the EUA. Please note that this EUA does not authorize face masks for use as personal protective equipment.

In addition to the "umbrella" EUA for Face Masks, as described in the FDA’s policy on face masks and surgical masks that is in effect during the COVID-19 public health emergency, the FDA does not expect manufacturers of face masks for a medical purpose that are not intended to provide liquid barrier protection to submit notification to the FDA before they begin marketing their product, or to comply with certain regulatory requirements, where the face mask does not create an undue risk in light of the public health emergency.

Under the policy, the FDA believes face masks not intended to provide liquid barrier protection do not create such an undue risk where:

The face masks include labeling that:
Accurately describes the product as a face mask (as opposed to a surgical mask or filtering facepiece respirator);
Includes a list of body-contacting materials (which does not include any drugs or biologics); and
Includes recommendations and general statements that would reduce the risk of use. For example, recommendations against use:
In any surgical setting or where significant exposure to liquid, bodily, or other hazardous fluids may be expected;
In a clinical setting where the infection risks level through inhalation exposure is high;
In the presence of a high intensity heat source or flammable gas;
The face masks are not intended for any use that would create such an undue risk. For example, the labeling does not include uses for antimicrobial or antiviral protection, infection prevention or reduction, or related uses, and does not include particulate filtration claims.

Q: I am interested in manufacturing surgical masks for COVID-19. What do I need to do?

During the COVID-19 public health emergency, and as described in the FDA’s policy on face masks and surgical masks that is in effect during the COVID-19 public health emergency, the FDA does not expect manufacturers of surgical masks intended to provide liquid barrier protection to submit notification to the FDA before they begin marketing their product, or to comply with certain regulatory requirements where the surgical masks do not create an undue risk in light of the public health emergency.

Under the policy, the FDA believes surgical masks intended to provide liquid barrier protection do not create an undue risk where:

The surgical masks meets liquid barrier performance consistent with ASTM F1862 standardExternal Link Disclaimer and the Class I or Class II flammability requirement per 16 CFR Part 1610 (unless labeled with a recommendation against use in the presence of high intensity heath source or flammable gas);
The surgical masks include labeling that accurately describes the product as a surgical mask and includes a list of the body contacting materials (which do not include any drugs or biologics); and
The surgical masks are not intended for any use that would create such an undue risk. For example, the labeling does not include uses for antimicrobial or antiviral protection, infection prevention or reduction, or related uses, and does not include particulate filtration claims.

Q: I would like to import masks for COVID-19. What do I need to do?

A: To avoid delays of legitimate shipments, we urge importers to review Importing Supplies for COVID-19 and instructions to importers for important information about importing products, including face masks and surgical masks, to ensure that the proper documentation is submitted at the time of entry. The FDA is ready and available to engage with importers to minimize disruptions during the importing process. If you have questions related to the general importation process, you may email COVID19FDAIMPORTINQUIRIES@fda.hhs.gov. If you have questions regarding an active entry, please contact the FDA office covering your port of entry by visiting the FDA Import Offices and Port of Entry page.

Q: I would like to purchase masks for COVID-19. How do I know if they are counterfeit or fraudulent?

A: The FDA does not issue any kind of certification to demonstrate a manufacturer is in compliance with the FDA’s requirements.

The FDA does not have an exhaustive list of all counterfeit or fraudulent products. To report fraudulent COVID-19 products to the FDA, please email FDA-COVID-19-Fraudulent-Products@fda.hhs.gov.
Q: I would like to purchase masks for health care workers during the COVID-19 Pandemic. How can I get them?

A: The FDA does not have a list of mask suppliers. If you are a health care facility, check with your supplier, distributor, or your local health department.

Q: I would like to donate masks to health care workers during the COVID-19 pandemic. How can you help me with my donation?

A: The FDA does not purchase or distribute masks. If you are interested in donating masks, please see COVID-19 Offer of Medical Supplies or Equipment.
Q: I would like to reuse masks during the COVID-19 pandemic. What do I need to do?

A: In this period of high demand for masks, there are conservation strategy to mitigate shortages of masks.
Q: Can a mask claim conformance with a National Institute for Occupational Safety and Health (NIOSH) filtration efficiency standard?

A: No. Masks cannot make any claims to meet a NIOSH filtration efficiency standard. Such claims can only be made for a respirator, when the respirator meets a specified filtration efficiency.

Next Steps

If you are still interested in manufacturing face masks and/or surgical masks for use during the COVID-19 pandemic, review these documents:
FDA Documents

Enforcement Policy for Face Masks and Respirators During the Coronavirus Disease (COVID-19) Public Health Emergency (Revised)
Emergency Use Authorization for Face Masks (PDF- 98KB)
FAQs on the Emergency Use Authorization for Face Masks (Non-Surgical)
Surgical Mask and Gown Conservation Strategies: Letter to Health Care Providers
N95 Respirators and Surgical Masks (Face Masks) including this section, Comparing Surgical Masks and Surgical N95 Respirators

Other Documents

ASTM standards and COVID-19 PPE
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Easy Flow Personal Air Filtration System

https://www.easyflowusa.com/how-it-works

(This is for informational and educational purposes only , and should not be considered as spam , or an endorsement to buy this product)


Professionals from industries all over the world wear respiratory systems and surgical respirator to protect their health from hazardous chemicals and harmful dusts. However, research has shown that wearing a surgical respirator does little to protect you from harmful particulate matter (PM .3).


In fact, wearing a respirator for long periods of time can cause discomfort, and may induce physiological stress on the wearer, making regular tasks more challenging, causing headaches, and other serious side effects. Easy Flow provides a positive pressurized flow of filtered fresh air directly inside the respirator!

This positive pressurized flow of air helps to block contaminated air from entering through the gaps making your respirator more effective and comfortable! Enjoy filtered air anytime, anywhere you go. Let the Easy Flow Personal Air Filtration System help block virtually all the particulate matter from entering your lungs and the entire cardiovascular system. Easy Flow’s positive air flow creates a dryer, more effective respirator that protects you from these harmful airborne pollutants!
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Masks and face coverings are effective in reducing the spread of airborne particles

9/26/20


https://www.news-medical.net/news/20200 ... icles.aspx

Laboratory tests of surgical and N95 masks by researchers at the University of California, Davis, show that they do cut down the amount of aerosolized particles emitted during breathing, talking and coughing.


Tests of homemade cloth face coverings, however, show that the fabric itself releases a large amount of fibers into the air, underscoring the importance of washing them
. The work is published Sept. 24 in Scientific Reports.

As the COVID-19 pandemic continues, the use of masks and other face coverings has emerged as an important tool alongside contact tracing and isolation, hand-washing and social distancing to reduce the spread of coronavirus.

The CDC and the World Health Organization endorse the use of face coverings, and masks or face coverings are required by many state and local governments, including the state of California.

The goal of wearing face coverings is to prevent people who are infected with COVID-19 but asymptomatic from transmitting the virus to others. But while evidence shows that face coverings generally reduce the spread of airborne particles, there is limited information on how well they compare with each other.

Sima Asadi, a graduate student working with Professor William Ristenpart in the UC Davis Department of Chemical Engineering, and colleagues at UC Davis and Icahn School of Medicine at Mount Sinai, New York, set up experiments to measure the flow of particles from volunteers wearing masks while they performed "expiratory activities" including breathing, talking, coughing and moving their jaw as if chewing gum.

Asadi and Ristenpart have previously studied how people emit small particles, or aerosols, during speech. These particles are small enough to float through the air over a considerable distance, but large enough to carry viruses such as influenza or coronavirus. They have found that a fraction of people are "superemitters" who give off many more particles than average.

The 10 volunteers sat in front of a funnel in a laminar flow cabinet. The funnel drew air from in front of their faces into a device that measured the size and number of particles exhaled. They wore either no mask, a medical-grade surgical mask, two types of N95 mask (vented or not), a homemade paper mask or homemade one- or two-layer cloth mask made from a cotton T-shirt according to CDC directions.

Up to 90 percent of particles blocked

The tests only measured outward transmission -- whether the masks could block an infected person from giving off particles that might carry viruses.

Without a mask, talking (reading a passage of text) gave off about 10 times more particles than simple breathing. Forced coughing produced a variable amount of particles. One of the volunteers in the study was a superemitter who consistently produced nearly 100 times as many particles as the others when coughing.

In all the test scenarios, surgical and N95 masks blocked as much as 90 percent of particles, compared to not wearing a mask. Face coverings also reduced airborne particles from the superemitter.

Homemade cotton masks actually produced more particles than not wearing a mask. These appeared to be tiny fibers released from the fabric. Because the cotton masks produced particles themselves, it's difficult to tell if they also blocked exhaled particles. They did seem to at least reduce the number of larger particles.

The results confirm that masks and face coverings are effective in reducing the spread of airborne particles, Ristenpart said, and also the importance of regularly washing cloth masks.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Combination of heat and high relative humidity can disinfect N95 mask materials

9/26/20


https://www.news-medical.net/news/20200 ... rials.aspx

As the COVID-19 pandemic swept around the world early this year, shortages of protective equipment such as N95 masks left healthcare workers little choice but to reuse the masks they had - increasing the risk of infection for both them and their patients.

Now, researchers at the Department of Energy's SLAC National Accelerator Laboratory, Stanford University and the University of Texas Medical Branch may have a solution: Using a combination of moderate heat and high relative humidity, the team was able to disinfect N95 mask materials without hampering their ability to filter out viruses.

What's more, it should not be too difficult to turn the new results into an automated system hospitals could use in short order - because the process is so simple, it might take just a few months to design and test a device.

"This is really an issue, so if you can find a way to recycle the masks a few dozen times, the shortage goes way down. You can imagine each doctor or nurse having their own personal collection of up to a dozen masks. The ability to decontaminate several of these masks while they are having a coffee break will lessen the chance that masks contaminated with COVID viruses would expose other patients."

-Steven Chu, Study Senior Author and Physicist, Stanford

The team reported their results September 25th in the journal ACS Nano.

Facing a shortage of the masks early this year, researchers considered a number of ways to disinfect them for reuse, including ultraviolet light, hydrogen peroxide vapors, autoclaves and chemical disinfectants. The problem is that many of those methods degrade N95 masks' filtering abilities, so that at most they could be reused a few times.

In the new study, Chu, University of Texas Medical Branch virologist Scott Weaver and Stanford/SLAC professors Yi Cui and Wah Chiu and colleagues focused their attention on a combination of heat and humidity to try to decontaminate masks.


Working at the World Reference Center for Emerging Viruses and Arboviruses, which has biosafety measures in place for working with the most contagious viruses, the team first mixed up batches of SARS-CoV-2 virus in liquids designed to mimic the fluids that might spray out of our mouths when we cough, sneeze, sing or simply breathe. They next sprayed droplets of the brew on a piece of meltblown fabric, a material used in most N95 masks, and let it dry.

Finally, they heated their samples at temperatures ranging from 25 to 95 degrees Celsius for up to 30 minutes with relative humidity up to 100 percent.

Higher humidity and heat substantially reduced the amount of virus the team could detect on the mask, although they had to be careful not to go too hot, which additional tests revealed could lower the material's ability to filter out virus-carrying droplets. The sweet spot appeared to be 85 degrees Celsius with 100 percent relatively humidity - the team could find no trace of SARS-CoV-2 after cooking the masks under those conditions
.

Additional results indicate masks could be decontaminated and reused upwards of 20 times and that the process works on at least two other viruses - a human coronavirus that causes the common cold and the chikungunya virus.

Weaver said that although the results are not especially surprising - researchers have known for a long time that heat and humidity are good ways to inactivate viruses - there hadn't been an urgent need for a detailed quantitative analysis of something like mask decontamination until now. The new data, he said, "provide some quantitative guidance for the future."

And even after the coronavirus pandemic is over, there are likely benefits, in part because of the method's application beyond SARS-CoV-2 to other viruses, and because of the economic and environmental benefits of reusing masks. "It's good all around," Cui said.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

An effective Origami mask for COVID-19

10/5/20


https://www.news-medical.net/news/20201 ... ID-19.aspx

Image :

https://www.news-medical.net/image.axd? ... 325&ri=850


A new study published on the preprint server medRxiv* in September 2020 reports constructing disposable masks using simple paper folding or origami steps, from filter material. This could make mask-wearing more acceptable and their construction less cumbersome.
The Importance of Respiratory Transmission

Most respiratory diseases are transmitted via pathogens contained within droplets and aerosols, emitted during ordinary breathing, talking, sneezing, and coughing. A surgical mask creates a barrier to such pathogens to prevent new infections.

In the current COVID-19 pandemic, the lack of effective antivirals or vaccines has made it essential to use such non-pharmaceutical interventions to reduce respiratory spread, including social distancing and the use of face coverings by all individuals when in a public space. In some places, mask production and distribution have been severely tested, forcing those in the frontline to make their own.

Both the public and essential workers in poorer countries use improvised cloth masks even though their effectiveness is inadequately studied. Surgical masks decrease the odds of droplet spread from the wearer to others, and also partially prevent transmissions from sprayed or splashed body fluids. However, their filtration and the facial fit is insufficient to offer respiratory protection. Even so, surgical masks have been demonstrated to reduce infection odds in healthcare workers, though in small studies.

Issues with Currently Available Masks


High-quality masks like the well-known N95 respirators protect the user by fitting the facial contours well, keeping out droplets and aerosol particles. They are better at preventing air leakage during a cough or sneeze compared to surgical masks. However, some authorities continue to recommend that these be used only by healthcare workers and those in close contact with known or suspected patients.

The World Health Organization (WHO) recommends that all medical personnel use medical-grade masks, and N95 respirators or their equivalent be used when performing any procedure likely to generate an aerosol in suspected patients.

On the other hand, the growing evidence that asymptomatic and presymptomatic transmission make up a large percentage of all respiratory spread, it is highly desirable that all individuals wear masks designed to offer filtration and fit characteristics comparable to that of respirators.

These are dependent mainly on the filtration material used and the design. Filter fabrics have ranged from cotton, silk, chiffon, and surgical drape fabrics. However, the fit is another primary consideration, since even the best material can fail to shield if the mask leaves gaps between itself and the face. In fact, studies show that filtration efficiency can be less by up to 60% in such a situation.

Secondly, materials that are excellent filters also make it harder to breathe, and the increased resistance to the flow of air through the mask makes it more likely that air will leak through the sides.

Objectives for Improvised Mask Construction

The current study aims to present a method of making an improvised mask suitable for protection against respiratory viruses and can be made without any particular expertise or supplies.

The objectives were to produce an affordable mask, with minimal leakage around the edges, offering efficient filtration and easy breathing, thus providing much more comfort and promoting the use of masks by more people. It does not involve sewing, and little manual labor is required, thus making it possible to produce large numbers in a short period of time.

The WHO recommends that the French Standardization Association (AFNOR Group) standard for non-medical masks be used for the public. This standard (S76-00137) takes into account the need for efficient filtration to at least 70%, but also breathability, with the maximum inhalation and exhalation resistance being 2.4 and 3 mbar, respectively.

AFNOR recommends a 3-ply mask design. The innermost layer is absorbent, the middle is non-woven with high filtration efficiency, and the outermost is weatherproof. The shape is also important, with AFNOR recommending the duckbill shape that keeps leakage low.

Design and Characteristics of a Good Mask

The current study is based on these recommendations. It proposes a mask design that makes it safe for both frontline workers who have numerous contacts with the public but may not have access to high-quality masks and the general public. The former may include staff in nursing homes, education, childcare, hospitality industry, and public transport, as well as emergency responders and healthcare workers.

The researchers looked at the filtration efficiencies of 18 kinds of materials, some of which are multilayered hybrid materials and the combined effect of filtration efficiency and fit on the total protection offered by the mask. The highest filtration efficiency was found to be at nearly 100% for a 2-layer furnace filter, and only 5% for NWPP, the material used in shopping bags.

However, materials that have excellent filter characteristics also have higher pressure drops, which promotes higher leakage. The way out is to use those materials that are designed for filtration, such as furnace filters and Filti brand filter media.

The researchers sum up their findings, “Masks with higher upper bound filtration efficiencies often exhibited larger total efficiency ranges, implying that high-efficiency media typically possess high-pressure drops, which ultimately results in mask leakage.”

Finding the Right Fit


The researchers tested 15 different mask designs, including those based on single- and double-ply and hybrid materials for fit testing. They also tested five mask designs, 1F, iH, H1, H2, H3, which meet AFNOR SPEC S76-001 standards for both filtration and pressure drop.

Mask leakage was also determined on fit testing, which better simulates real-life situations rather than earlier studies where the media were tested rather than masks, and leakage was simulated by making tiny holes in the sample tube downstream of the filter medium.

They found that surgical and KN95 reference masks showed excellent ideal filtrations efficiency of 95% and 93% filtration efficiency at 300 nm, respectively. Under nominal or unsealed conditions, however, their performance dropped drastically to 30%.

For the latter type of mask, the ear loops are to blame, they suggest, since this reduces the fit. Using head straps will prevent leakage much better.

Their tests showed that the 2-ply Filti masks (2F) performed very well, with a high filtration efficiency and a high-pressure drop but low leakage.

Thus, “our results reveal that filtration performance is dominated by mask fit and that reducing the pressure drop of the filter material attenuates leakage.”

They also tested the fit on a human being with the quantitative fit test OSHA Specification 1910 as the reference. The results suggest that under actual-use conditions, the origami mask is just as efficient at filtration than the ideal conditions under which it is tested on the mannequin. The widest gap in efficiencies derived from the OSHA fit test and the mannequin-based test were seen with the KN95 with ear loops and the surgical mask, and this was due to leakage.

Implications

The researchers conclude that this origami technique can be used to construct a range of masks with optimum filtration-pressure drop balance for best performance. By using the right filter media, they can offer better protection than the commercially available respirators, with high filtration efficiency, a lower pressure drop, and minimal leakage.

The benefits of this origami fabrication procedure are its flexibility, allowing adaptation to multiple facial sizes, optimal choice of filter media for filtration efficiency vs. pressure drop, and allows for comfortable wearing with easy breathing. This could help encourage more people to accept universal mask usage.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Engineers invent plant-based spray that could be used in N95 mask filters

10/7/20


https://www.news-medical.net/news/20201 ... lters.aspx

Engineers have invented a way to spray extremely thin wires made of a plant-based material that could be used in N95 mask filters, devices that harvest energy for electricity, and potentially the creation of human organs.

The method involves spraying methylcellulose, a renewable plastic material derived from plant cellulose, on 3D-printed and other objects ranging from electronics to plants, according to a Rutgers-led study in the journal Materials Horizons.

" This could be the first step towards 3D manufacturing of organs with the same kinds of amazing properties as those seen in nature. In the nearer term, N95 masks are in demand as personal protective equipment during the COVID-19 pandemic, and our spray method could add another level of capture to make filters more effective. Electronics like LEDs and energy harvesters also could similarly benefit."

-Jonathan P. Singer, Study Senior Authorand Assistant Professor, Department of Mechanical and Aerospace Engineering, School of Engineering, Rutgers University-New Brunswick

Thin wires (nanowires) made of soft matter have many applications, including the cilia that keep our lungs clean and the setae (bristly structures) that allow geckos to grip walls.

Such wires have also been used in small triboelectric energy harvesters, with future examples possibly including strips laminated on shoes to charge a cell phone and a door handle sensor that turns on an alarm.

While people have known how to create nanowires since the advent of cotton candy melt spinners, controlling the process has always been limited. The barrier has been the inability to spray instead of spin such wires.

Singer's Hybrid Micro/Nanomanufacturing Laboratory, in collaboration with engineers at Binghamton University, revealed the fundamental physics to create such sprays. With methylcellulose, they have created "forests" and foams of nanowires that can be coated on 3D objects. They also demonstrated that gold nanoparticles could be embedded in wires for optical sensing and coloration.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Face masks far more protective against COVID-19 than face shields, CDC experts

10/8/20


https://www.news-medical.net/news/20201 ... perts.aspx

Researchers from the Centers for Disease Control and Prevention (CDC) have conducted a study showing that face masks and neck gaiters appear to be much more effective than face shields at reducing the expulsion of respiratory aerosols that could potentially transmit severe acute respiratory syndrome 2 (SARS-CoV-2).

SARS-CoV-2 is the agent responsible for the current coronavirus disease 2019 (COVID-19) pandemic that continues to pose an ongoing threat to global public health and the economy.

Using a cough aerosol simulator to expel small aerosol particles into different face coverings, the team found that the N95 respirator, procedure mask, cloth mask, and neck gaiters effectively reduced the emission of the aerosols, while the face shield was not.

“Our results suggest that face masks and neck gaiters are preferable to face shields as source control devices for cough aerosols,” writes William Lindsley and colleagues.

A pre-print version of the paper is available in the server medRxiv*, while the article undergoes peer review.

Community transmission can occur through infected aerosol droplets

SARS-CoV-2 can be transmitted from person to person via large respiratory aerosols (diameter greater than around 10µm) that are produced when an infected person coughs, sneezes, breathes, talks, or sings.

However, smaller aerosols are also emitted during these activities, suggesting that short-range airborne virus transmission might also be possible.

To protect against this potential route of community transmission, various public health bodies, including the CDC and the World Health Organization (WHO) have recommended that the general public wear face masks or other face coverings as source control devices.

“Source control devices are intended to protect other people from infectious aerosols emitted by the wearer, as compared with personal protective equipment such as N95 respirators which are primarily intended to protect the wearer,” explains the team.

However, people often dislike wearing face masks, and compliance levels can be low and inconsistent, say the researchers.

People may repeatedly remove and replace the mask and keep adjusting it, which can contaminate the hands. This potentially leads to the transmission of the virus, particularly in cases where the masks are re-used.

Face shields were proposed as an alternative

In an opinion article in the Journal of the American Medical Association, researchers suggested that face shields may be more effective at reducing community transmission because they are more comfortable and, therefore, more likely to be widely adopted by the public.

However, few studies have examined face shields as source control devices, and quantitative data on efficacy is lacking.

What did the current study involve?

Now, Lindsley and colleagues have used a cough aerosol simulator to eject a cloud that simulates small respiratory aerosols (0 to 7µm in diameter) into different types of face coverings and assessed the quantity of particles that were able to travel through and around each device.

The researchers tested the collection efficiencies (the fraction of the aerosols blocked by the device) of an N95 respirator, a medical procedure mask, a commercial 3-ply cloth face mask, a polyester neck gaiter, and a commercial disposable face shield.

Neck gaiters are worn either as a single layer of fabric or as a folded, two-layer fabric. For the experiments carried out in this study, the researchers tested both configurations.

Face masks and gaiters were much more effective than the face shield


On average, the N95 respirator stopped 99% of the total cough aerosol being expelled into the environment, while the procedure mask blocked 59%, and the cloth face mask blocked 51%.

The neck gaiter blocked 47% of the cough aerosol when it was worn as a single layer and 60% when it was worn as a double layer.

The face shield, on the other hand, only stopped 2% of the cough aerosol being expelled into the atmosphere.

There were no significant differences in the collection efficiencies of the procedure mask, cloth mask, and neck gaiter, but all of these devices were significantly more effective than the face shield.

“Our results suggest that face coverings are more effective than face shields as source control devices to reduce the expulsion of respiratory aerosols into the environment as a public health measure to reduce the community transmission of SARS-CoV-2,” concludes the team.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Cloth masks should be machine washed daily during COVID-19, study says

10/11/20


https://www.news-medical.net/news/20201 ... -says.aspx

Amid the coronavirus pandemic, health experts reiterate infection control measures, such as frequent hand washing, wearing masks, and social distancing, which are vital means to prevent infection. Many health agencies recommend covering the mouth and nose with cloth masks to prevent depleting the supply of medical and surgical masks among health care workers.

A team of researchers reports that cloth masks effectively protect against infection if they are washed every day. The researchers recommend daily washing of cloth masks at high temperatures to reduce the likelihood of contamination and transmission of viruses such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease (COVID-19).

Efficacy of cloth masks in preventing viral infections

In previous randomized controlled trials (RCT) in hospital healthcare workers, cloth masks resulted in a higher risk of respiratory infections compared with medical masks. The current study was the only published RCT of cloth masks amid the coronavirus pandemic.

The study aims to perform a post hoc analysis of unpublished data on mask washing and contamination from the original RCT to provide a better understanding of the poor performance of two-layered cotton cloth masks used by healthcare workers in the previous study.

The original RCT was published in 2015 in the journal Infectious diseases and has been the only RCT ever conducted on the effectiveness of cloth masks in preventing viral infections. It was conducted in 2011 among hospital workers in Vietnam.

The team studied results from a subgroup of 607 healthcare workers in selected high-risk areas in secondary and tertiary-level hospitals in Hanoi, Vietnam. These healthcare workers used a two-layered cloth mask and were part of a trial comparing medical or surgical masks and cloth masks.

The team has found that if cloth masks were washed in the hospital laundry, they were as effective as surgical or medical masks.

“Both cloth masks and surgical masks should be considered ‘contaminated’ after use,” Professor Raina MacIntyre, a study co-author, said.

“Unlike surgical masks, which are disposed of after use, cloth masks are re-used. While it can be tempting to use the same mask for multiple days in a row or to give it a quick hand-wash or wipe-over, our research suggests that this increases the risk of contamination,” she added.

The study findings showed that viral contamination with rhinovirus was detected on both used medical and cloth masks. Most of the healthcare workers said they washed their masks by hand. The study also revealed that the risk of infection was more than double among those who washed their masks on their own, compared to the masks that were washed in the hospital laundry.

Further, the team discovered that there was no difference between surgical or medical masks and cloth masks that were washed in the hospital laundry.

“Using a self-reported method of washing, we showed double the risk of infection with seasonal respiratory viruses if masks were self-washed by hand by HCWs. The majority of HCWs in the study reported hand-washing their mask themselves. This could explain the poor performance of two-layered cloth masks if the self-washing was inadequate,” the authors wrote in the paper.

They added that cloth masks washed in the hospital laundry were as protective as medical masks. It is important to wash cloth masks daily using the proper method, which may reduce the risk of being infected with COVID-19.

Applicable to the public

Though people wearing cloth masks in the public are unlikely to be exposed to the same amount of pathogens like viruses as healthcare workers, the researchers still recommend washing cloth masks every day, especially for those who are working outside their homes or those who need to go outside.

COVID-19 is a highly infectious virus, and there is still more to learn about it. It is essential to take precautions to protect oneself against the virus, like making sure masks are effective.

“The WHO recommends machine washing masks with hot water at 60 degrees Celsius and laundry detergent, and the results of our analysis support this recommendation,” Professor MacIntyre explained.

“Washing machines often have a default temperature of 40 degrees or 60 degrees, so do check the setting. At these very hot temperatures, hand-washing is not possible. The clear message from this research is that cloth masks do work – but once a cloth mask has been worn, it needs to be washed each time properly before being worn again; otherwise, it stops being effective,” she added.

Journal reference:

MacIntyre, R., Dung, T.C., Chughtai, A., Seale, H., and Rahman, B. (2020). Contamination and washing of cloth masks and risk of infection among hospital health workers in Vietnam: a post hoc analysis of a randomized controlled trial. Infectious Diseases. https://bmjopen.bmj.com/content/5/4/e006577
trader32176
Posts: 3557
Joined: Fri Jun 26, 2020 5:22 am

Re: Face Mask Technologies

Post by trader32176 »

Testing, tracing and mask-wearing can prevent COVID-19 resurgences

10/14/20


https://www.news-medical.net/news/20201 ... ences.aspx

Researchers in Australia, Denmark, and the United States have conducted a study showing the extent to which community testing, contact tracing, and mask-wearing can lower the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the Australian state of New South Wales.

SARS-CoV-2 is the agent responsible for the coronavirus disease 2019 (COVID-9) pandemic that continues to sweep the globe, increasingly posing a threat to global health and the economy.

Robyn Stuart (Burnet Institute, Melbourne) and colleagues say the study suggests that community testing, tracing, and mask-wearing can effectively control the spread of SARS-CoV-2 in community settings.

The findings also suggest that of all the interventions considered, symptomatic testing, contact tracing, and testing of contacts are the most important.

However, adopting a multi-faceted strategy that combines testing, tracing, and mask-wearing, alongside adherence to hand hygiene and social distancing protocols, is probably the most reliable way to ensure the community-based transmission is kept under control, advises the team.

A pre-print version of the paper is available on the server medRxiv*, while the article undergoes peer review.

The spread of SARS-CoV-2 is unprecedented

Since the first cases of COVID-19 were first identified in Wuhan, China, late last year, it quickly became evident that SARS-CoV-2 spreads at an unprecedented and potentially exponential rate.

“Therefore, as long as a substantial proportion of the population remains susceptible to infection, the potential for new epidemic waves persists even in settings with low numbers of active COVID-19 infections, unless sufficient countermeasures are in place,” writes Stuart and colleagues.

Across the globe, the mitigation measures introduced to contain the spread of the pandemic have already been very effective. During the second half of 2020, many governments decided to move from the strict, crisis-management approach to more relaxed strategies focused on minimizing the risk of transmission while also allowing previous societal and economic activities to resume.

When used in combination with hand hygiene and social distancing practices, community testing, contact tracing, and mask-wearing can allow for relatively high mobility, say the researchers.

“Testing and contact tracing means that only those at greatest risk of transmitting the virus need to stay home, while masks mean that people with undiagnosed infections present less of a risk to others,” they write.

Estimating how susceptible New South Wales is to a new epidemic wave

Now, Stuart and colleagues have examined the uptake of these approaches in the Australian state of New South Wales. This setting has seen prolonged low transmission, non-universal mask use, high mobility, and the use of a well-functioning test and trace system.

The researchers set out to explore how susceptible New South Wales would be to resurgences in the spread of SARS-CoV-2 between October 1st and December 31st, 2020, under different levels of testing, tracing, and mask-wearing.

“In New South Wales, mask use has been encouraged in particular settings since July, but not mandated; at the same time, there has been a strong focus on contact tracing,” they write. “In this study, we consider a range of testing and contact tracing levels, and assess the balance between masks, testing, and contact tracing as a means of controlling community-based transmission.”

What did the study find?

The team found that mask-wearing had the most significant relative effect on transmission when community testing and tracing rates were lower and the least impact when testing and tracing rates were higher.

With a very high testing rate - where 90% of symptomatic individuals and 90% of known case contacts were tested - the team estimated that the epidemic in New South Wales would be kept under control until at least the end of 2020, providing that rapid and effective contact tracing is in place.

If a very high testing rate is adopted, the team says the estimated number of new cases between October 1st and December 31st would be as few as 70–110 under a high mask uptake scenario, compared with 340 to 1,400 under a no mask scenario.

However, “if testing rates are lower, we estimate that mask use can play an important role in reducing the potential for epidemic resurgence,” say the researchers.

Across similar levels of mask-wearing and contact tracing, the number of new infection cases over the same period would be up to 6 times higher if the testing rate fell from 90% to 80%; 17 times higher if it fell to 65%, and more than 100 times higher if it fell to 50%.

A multi-faceted strategy is likely to be the most robust

“Of the interventions considered, this study suggests that maintaining high levels of symptomatic testing, contact tracing, and testing of contacts is the most important,” said Stuart and colleagues.

“However, pursuing a strategy that combines aggressive testing, high mask usage, and effective contact tracing, alongside continued hygiene and distancing protocols, is likely to be the most robust means of controlling community-based transmission of SARS-CoV-2,” they conclude.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:

Stuart R, et al Robust test and trace strategies can prevent COVID-19 resurgences: a case study from New South Wales, Australia. medRxiv, 2020. doi: https://doi.org/10.1101/2020.10.09.20209429
Post Reply