7 ms·

(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 i

by 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 ago
  Abstract doesn’t say if mice wore the mask or were exposed to air filtered by this mask
  - KylarkJ 7y ago
    Lethal 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 ago
      tl;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 ago
        The 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 ago
        They 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 ago
  They 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 ago
Yes, 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 ago
  real 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 ago
    But 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 ago
      Good point.
  - Brave-Steak 7y ago
    90% 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 ago
Now 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 ago
  I 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 ago
    If 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 ago
      Two 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 ago
        Using 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.

by ipsum2 7y ago

3fe9a03ccd14ca5 7y ago

> surgical mask with sodium chloride salt. Interesting that these masks really are not airtight, but still effective?

numpad0 7y ago
Abstract doesn’t say if mice wore the mask or were exposed to air filtered by this mask
- KylarkJ 7y ago
  Lethal 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 ago
    tl;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 ago
      The 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 ago
        They 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 ago
They 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 ago

Yes, 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 ago
real 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 ago
  But 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 ago
    Good point.
- Brave-Steak 7y ago
  90% 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 ago

Now 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 ago
I 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 ago
  If 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 ago
    Two 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 ago
      Using 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.