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Apple Faceshield

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Re: Apple Faceshield

#501

Earlier quoted context omitted.

This is untrue. Stanford Medicine released a study around March 22. The TLDR is 70°C heat for 30 mins. Avoid alcohol, it kills the static charge in the mask fibres. https://m.box.com/shared_item/https%3A%2F%2Fstanfordmedicine...

No, THAT’s untrue. Look at your own link. You can sterilize the mask to preserve its filtration ability, but no one has shown it maintains fit. A poorly fit N95 is no protection at all, which is why hc workers get formally fit tested when starting a new gig. Which is why That link makes “no one knows what it does to fit” one of its top line bulletpoints.

> A poorly fit N95 is no protection at all

There’s no plausible mechanism of action for masks under which this is true. A properly fitted N95 will block 95% of particles which is less than the kind of hazmat spacesuit with face shield and positive air pressure you’d ideally be wearing if working with someone with Ebola or similar. Maybe it really is impossible to get proper fit on a reused mask. Perhaps it’s only as good as a normal surgical mask which blocks just under 90% of virus sized particles.

Every reduction in the amount of virus that gets into your lungs makes it less likely that you’ll get infected and if infected gives your immune system more time to ramp up. That’s why people care about viral load. Running through someone’s cough is less likely to kill you than being in a small poorly ventilated room with someone coughing uncontrollably for minutes at a time.

Re: Apple Faceshield

#504
post #382

Earlier quoted context omitted.

> it seems pretty likely that I will be protected And you'd be wrong. Sure, a face shield will protect you from liquid streaming out at you (partially). However, it isn't a liquid that you need to protect yourself from in this instance... it is aerosolized particles. And those travel in the air. So when you breathe in, that air can and will move around the face shield. The sibling comment about smoke moving is exactl…

You say that with great confidence and a lack of sources; and I'm guessing we are equally ignorant on the actual physics of how small droplets move. The details aren't clear on how the virus is spreading. The virus might have multiple modes of transmission. Closing 2 of them reliably a great deal. There are important things to do with "catching COVID" that aren't binary; starting doses likely matter as well. I'd rath…

> starting doses likely matter as well.

That is something that I've been wondering about too. I work in biotech but not as a scientist. These things are tricky to nail down as they seem to be very individual specific. Theoretically, in an exponential growth model, it wouldn't matter if you were inoculated with 20000 or 200000 virons, after the incubation period post-infection, you're going to be generating a huge amount, millions and millions, of virus particles in either case. Certainly, if you keep getting exposed, you're immune system is going to get overwhelmed quickly, but for a single event, I don't think it matters.

Re: Apple Faceshield

#505

Earlier quoted context omitted.

This is just common sense. Aerosolized particles are not impeded by a shield. A shield is intended to obstruct ballistic projectiles. If those projectiles are aerosolized and are in the air that you breathe , then the shield will offer no protection at all. Even an N95 mask still can let in up to 5% of these particles. What efficacy is a piece of plastic in front of your face going to do against that?

> If those projectiles are aerosolized and are in the air that you breathe It seems like you're imagining that the mucus and saliva particles would behave like a gas, but it's a suspension of liquid particles in the air, which behaves slightly differently. Think of breathing onto glass -- a lot of the aerosol I expel adheres to the glass. Some smaller droplets may move around it, but it's still preferable to receive…

>but it's still preferable to receive a smaller dose of the virus.

Could you explain why you believe that? I haven't found anything definitive on this topic.

Re: Apple Faceshield

#506
post #485

Earlier quoted context omitted.

These are only used by doctors and nurses when treating patients with open airways at very close range to protect from direct splatters with body fluids. Eg when intubating a patient that’s having explosive coughing fits. They are also part of a complete protective system including a mask, elasticated hair cover, full body wrap aprons and long arm gloves. There is no point using a shield without the rest if the gear…

> There is no point using a shield without the rest if the gear because if you are in a situation where you need the shield, you also need the rest as well. This is the same class of bullshit the WHO, CDC and FDA were pushing about face masks less than a week ago. There is no way this is worse than nothing. If a face shield used with no other PPE reduces the viral load the average healthcare worker is exposed to by 1…

[dead]

Re: Apple Faceshield

#507

Earlier quoted context omitted.

> it seems pretty likely that I will be protected And you'd be wrong. Sure, a face shield will protect you from liquid streaming out at you (partially). However, it isn't a liquid that you need to protect yourself from in this instance... it is aerosolized particles. And those travel in the air. So when you breathe in, that air can and will move around the face shield. The sibling comment about smoke moving is exactl…

> this is how N95 masks are actually fit. (Well, not using smoke, but similar test). If you can smell the chemical used in the test, the fit is wrong. And if the smell is less strong than it would be if you weren’t wearing the mask the viral load you’ve been exposed to is smaller. You are less likely to be infected and if you are infected your immune system has more time to ramp up so you’re more likely to fight it o…

wanker

Re: Apple Faceshield

#508

Damn, the animations are smooth. But wish they made a better version of the adjustment mechanism. Feel like doctors will have a hard time adjusting the bands with their gloves on. Why not spend couple more cents and build in a clicking adjustment mechanism?? But overall, good job Apple :)

You would adjust it before you put all of your other PPE on.

Re: Apple Faceshield

#509
post #5

I’m sad that even though this unique design was done and put online for anyone to print by Prusa, he is hardly mentioned now. On top of that, the design is already commercialized. EDIT: I see now that the design is different, you’re right

When people start manufacturing and shipping a million a week, then perhaps the Prusa design would be worth mentioning.

Re: Apple Faceshield

#510
post #504
post #382

Earlier quoted context omitted.

You say that with great confidence and a lack of sources; and I'm guessing we are equally ignorant on the actual physics of how small droplets move. The details aren't clear on how the virus is spreading. The virus might have multiple modes of transmission. Closing 2 of them reliably a great deal. There are important things to do with "catching COVID" that aren't binary; starting doses likely matter as well. I'd rath…

> starting doses likely matter as well. That is something that I've been wondering about too. I work in biotech but not as a scientist. These things are tricky to nail down as they seem to be very individual specific. Theoretically, in an exponential growth model, it wouldn't matter if you were inoculated with 20000 or 200000 virons, after the incubation period post-infection, you're going to be generating a huge amo…

Viral dose does indeed matter. https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral...

It’s analogous to containing a new virus outbreak before it becomes an exponentially growing pandemic.

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