On Tue, 8 Jan 2008 03:42:50 -0800 (PST), IsaacKuo <mechdan@[EMAIL PROTECTED]
>
wrote:
>On Jan 7, 8:03 pm, Wildepad <noreplies> wrote:
>> On Mon, 7 Jan 2008 08:38:28 -0800 (PST), IsaacKuo <mech...@[EMAIL PROTECTED]
>
>> wrote:
>
>> >On Jan 7, 4:13 am, Wildepad <noreplies> wrote:
>
>> >> The first might be simple, and I'm surprised that more virii
occurring
>> >> in nature don't use it -- the sweat glands in the palms (merocrine?)
>> >> seem ideal for transfer as the pressure of a handshake could easily
>> >> force a virus down the short duct.
>
>> >It's not at all ideal, for what should be obvious reasons. Skin
>> >is anti-germ armor. If a little pressure was all it took to squeeze
>> >germs through, then it wouldn't be doing its job.
>
>> True, but there are chinks in any armor. The function of the sweat
>> glands must outweigh other considerations, but they are still an
>> opening, and openings can be exploited.
>
>Since diseases don't seem to exploit hand sweat glands
>much, but they do exploit the hand->mouth opening a lot, it
>would seem that the latter is the more practical opening to
>exploit.
Obviously it is. The fact that they can so easily reproduce means that
even though each one has little chance of encountering a victim, the
sheer volume of them makes it practical.
Yet it still seems odd to me that at least a few diseases haven't
found a niche by using a plant as a vector or transmission by touch.
Life does so want to reproduce that it finds ways one might never
expect (no matter which side you are on in the "a virus is alive/a
virus isn't alive" debate, you have to admit that they do love to find
new places to reproduce).
>But if we just look at the physics of things, why should the
>pressure of a handshake be sufficient to push fluid down a
>sweat duct? It doesn't seem plausible to me due to the
>narrow diameter of the duct--but I'm not sure how to go
>about calculating how far fluid would be pushed.
>
>To a first approximation, I think fluid wouldn't be pushed
>into the sweat gland at all. You can consider the flesh cells
>to be flexible membranes around incompressible fluid, and
>the sweat fluid to be incompressible also. External pressure
>would result in a pressure gradient, but no local pressure
>points preferring to push the sweat inward.
I doubt anyone has ever researched it.
If not pushed in directly, what about sucked in? Pressure deforms the
cells surrounding the ****e, clamping it closed, but when the pressure
is released, the ****e opens, creating suction.
There must be some mechanism which prevents viral transmission by
touch, but there's a way around everything, and as I said, I'm just
surprised that a virus doesn't use it more often.
--
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