6 ms·
Universal, reusable virus deactivation system for respiratory protection (2017)
- ipsum2 7y ago(2017). Also, no pictures of the mice with the masks on. The methods section seems pretty easy to replicate, just dissolve some salt in water (concentrations in paper), soak it in the masks, and dry in a low-temp oven.
- 3fe9a03ccd14ca5 7y ago> surgical mask with sodium chloride salt. Interesting that these masks really are not airtight, but still effective?
- numpad0 7y agoAbstract doesn’t say if mice wore the mask or were exposed to air filtered by this mask
- KylarkJ 7y agoLethal infectivity of influenza viruses (CA/09 H1N1) was examined in 8 week old female inbred BALB/c mice (Nara Biotech; Seoul, Korea) by using the intranasal route. For bare and salt-coated filters, 12 mice per group were infected with individual penetration dosage of influenza virus through each filter
- yetihehe 7y agotl;dr - they used samples of virus taken from filters and directly infected mice with those samples. Bare filters - all mice dead. Salted filters - all mice a little sick for a week and then back to normal.
- jakeogh 7y agoThe paper talks about the microdroplets getting dehydrated (and I assume trapped) by the salt. Why do they get sick at all? Is it because the virus loading is drastically lower and their immune system can stay ahead of it's replication curve? What a fantastic time to be alive.
- yetihehe 7y agoThey speculate that viruses shape is altered by recrystallization of salt and they are damaged/uneffective, but still have some small virulency which is enough to trigger immune system.
- red0point 7y agoThey are airtight in this study. From the abstract: When tested with tightly sealed sides, salt-coated filters showed remarkably higher filtration efficiency than conventional mask filtration layer, and 100% survival rate was observed in mice infected with virus penetrated through salt-coated filters.
- dgacmu 7y agoYes, but note they added a surfactant as well (tween 20 / polysorbate 20), and I didn't spot a control of surfactant-only. They also didn't seem to report the effects of the salting on airflow through the mask, but I'm tired and read the article quickly. Seems nifty, but I'd also expect real world efficacy to be lower than reported here due to improper mask sealing under normal use.
- contingencies 7y agoreal world efficacy to be lower than reported here due to improper mask sealing under normal use. That problem affects all mask use. I read a 2010 paper[0] this week which IIRC showed that normal mask types (pre-formed, soft-multilayered surgical, etc.) all had about 30% of the efficiency of N95 masks. For the N95 masks, they failed to get 95%, more like 90%, due to poor fit. A silicone pressure fit type is really important. No unixbeards allowed! >:( [0] https://journals.sagepub.com/doi/pdf/10.1177/153567601001500204 https://journals.sagepub.com/doi/pdf/10.1177/153567601001500...
- sgc 7y agoBut since salt impregnation almost certainly reduces air flow, there would likely be a higher real world failure rate for salt impregnated masks. I would not be at all surprised if this was a worse negative than the salt improvement in real world conditions.
- contingencies 7y agoGood point.
- Brave-Steak 7y ago90% seems good with poor fit. That's a far cry from people saying its pointless to use N95 masks outside of a hospital setting.
- contingencies 7y ago
- FriedPickles 7y agoNow that it's free and easy to take photos and videos, I don't understand why research papers don't come with copious attached media showing methods.
- wyattpeak 7y agoI don't know that adding material kitchen-sink-style would necessarily be helpful. Something loaded down with hundreds of pages of addenda is as likely to make itself harder to follow as it is easier, as well as adding considerably to writing and editing time. If a point is unclear it'll likely be caught by reviewers, if it's not the researcher's contact details are there on the paper.
- nwah1 7y agoIf websites and footnotes are structured well, it should be quite easy to allow people to dive more deeply into such things without distracting those who don't care.
- wyattpeak 7y agoTwo concerns: - I'm unconvinced that hyperlinked websites are a good idea as a primary format for research. Research needs to be accessible in perpetuity. We've proven atrocious at keeping websites available and software running. - Lots of properly structured footnotes and labelled photos are, as I mentioned earlier, a large timesink. Writing papers is already a substantial time investment, which both distracts from other research and can dissuade researchers from publishing more minor results. Both of these are superable for the right reasons (e.g. CS research by its nature needs digital components), but adding material because photos are cheap isn't to my mind the right reason.
- nwah1 7y agoUsing lab automation equipment, and listing out which equipment was used is another step in the right direction. I'm thinking about it from the perspective of a software developer for whom things like jenkinsfiles, vagrantfiles, and CloudFormation templates are a thing. Science should have a similar standardized domain-specific way to specify their experiment setup procedures.
- KylarkJ 7y agosurfactant (Tween 20) is probably important for crystals to form on filter fibers and not bee loose in filter Could dishwasher soup or or Washing machine powder do the job?
- AstralStorm 7y agoThose might work if you pick one without anionic surfactants. (Those will bind sodium creating soapy residue.) Most importantly, use deionised water, and measure how much salt is on the actual mask. (Electrical impedance submerged in deionised water vs reference mask would work.)
- amluto 7y agoAre you sure you aren’t thinking of calcium? Sodium carboxylates and sodium lauryl sulfate should already be bound to as much sodium as they want.
- KylarkJ 7y agoTLDR • 100% survival rate was observed in mice infected with virus penetrated through salt-coated filters. • Mice exposed to a dose penetrated through the bare filter showed rapid body weight loss, followed by death within 10 days after infection • (PP) microfiber filter, was coated with NaCl salt as an active virus negation unit • The coating formulations contained surfactant to enhance wetting of saline solution on the surface of hydrophobic PP fibers • The coating solution was prepared by dissolving sodium chloride NaCl in filtered DI water under stirring at 400 rpm and 90 °C, followed by the addition of Tween 20 to a final concentration of 29.03 w/v% of NaCl and 1 v/v% of Tween 20. • the mask bare PP filters were pre-wet to contain approximately 600 μL of coating solution by incubating overnight at room temperature. Any remaining dry areas were removed by applying gentle strokes with tweezers to the filters while immersed in the coating solution. Subsequently, the filters were deposited in the desired volume of coating solution (0, 100, 300, 600, 900 and 1200 μL, of which corresponding membranes are abbreviated as Filterwet, Filterwet+100μL, Filterwet+300μL, Filterwet+600μL, Filterwet+900μL, and Filterwet+1200μL, respectively) on petri dishes (60 × 15 mm; Fisher Scientific) to control the amount of NaCl per unit area and dried in an oven (Isotemp Incubator, Fisher Scientific) at 37 °C for 1 day.
- shele 7y agoIt is almost not a study about filters, but a study about an ad hoc vaccine by partially inactivating the virus by drying it on a surface with salt and surfactant.
- Angostura 7y agoPerhaps a 'virocide', but not a vaccine, since those prompt mobilisation of the body's immune system.
- qwerty456127 7y agoSo how do we possibly use this? What if I soak regular mask (I have a cache of simple ones, not surgical) in a strong saline solution and then dry it - how much effective is it going to be against flu and 2019-nCoV?
- wongarsu 7y agoWithout testing it, it seems unlikely you would get enough airflow. If it works at all then only through a perfectly sealing mask, as others point out. Maybe treating the filter of a cheap air purifier could have positive effects against airborne diseases indoors?
- imvetri 7y agoHuman and rats share some genes. But there are gene characteristics that are unique to one but can't be found in other. Namely 1. Disrespect / fail to see / Ignore the presence of life in other species. 3. Superior complexity + Good thinking skills = Degrading survival instinct & arise of misconception-delusional science logics.
- imvetri 7y agoYo downvoters. I'm counting for those 4 downvoters and everyone else who had much more less courage to at least put effort to talk. Argue back
- yetihehe 7y agoArgue with what? You can't even make properly numbered list (where is number 2?), also "Disrespect" is not a "gene characteristic".
- deleted 7y ago[deleted]
- SirSavary 7y agoNot entirely sure what you expect people to "argue back". Why not dial down the hostility and request a debate instead?