h a l f b a k e r yI CAN HAZ CROISSANTZ?
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
There has been a recent flurry of documentaries about
Scott. For clarity, I should explain that I am referring to
Robert Falcon, not Ridley nor even Sir Walter.
One of Scott's mistakes, apparently, was in not making
due
allowance for the greatly increased calorie consumption
of
men in
the Antarctic. In consequence, he seems to have
planned a diet of generous quantities of Huntley and
Palmer's biscuits, horse flesh and cocoa. Such fare would
be ample under normal circumstances (and, apart from
the
horse flesh, is standard English fare), but failed dismally
in
the nip of the Antarctic.
To quote from one documentary "Scott and his men were
slowly starving to death without even realizing it."
Now, if you take out the "to death" part, what you have
is
clearly the holy grail of weight-loss programs. Which of
us
would not like to shed excess weight "without even
realizing it"? (It was a rhetorical question.)
I therefore believe that there is good money to be made
by
organising on-foot expeditions to Scott's hut for the
portly.
Rabbit starvation
http://en.wikipedia...i/Rabbit_starvation
[ytk, Jun 26 2012]
"Tin Pest"
http://en.wikipedia...ition_to_Antarctica
Not proven. [8th of 7, Jun 28 2012]
[link]
|
| |
Mysteriously Still Portly Gentleman With Toothpick: |
|
| |
"Well, first Adams went out for a walk, said he'd be back in a bit, then Burgens, Riddley and Thompson took a morning constitutional, then Smith...". |
|
| |
"Two go thin; only one becomes stout." |
|
| |
Will the participants get their Oates ? |
|
| |
Isn't this known as rabbit starvation? (link) |
|
| |
No, the main problem with Scott's men was simple
lack of calories, although they were also short of
vitamins. |
|
| |
And, seemingly, any detectable instinct for self-preservation (except by freezing). |
|
| |
//any detectable instinct for self-preservation
(except by freezing).// Well, there go cryonics
shares. |
|
| |
I see. But I wonder how one might go about starving to death without realizing it? |
|
| |
“I say, old bean, you're looking a touch emaciated this morning. Are you quite
sure you're not at all hungry?” “Oh, rather; I daresay I shan't require sustenance
again until supper.” “Do you mean to say you intend to skip afternoon tea entirely?
Good Lord! What barbarians these conditions make of us…” |
|
| |
Mertz died of, and Mawson suffered greatly from, Vitamin A poisoning caused by eating the livers of their sled dogs. |
|
| |
Yes, that was odd - they ate the livers of their dogs (the poisonous bit), but didn't eat the rest. |
|
| |
In mammals, cold can be counteracted by selectively
uncoupling the mitochondrial membrane potential.
This is achieved by a number of specialist uncoupling
proteins; UCPs. The idea being that if you expend
chemical energy pumping protons against a gradient,
then just release them again, you've got a heat
machine. The same effect can be had by taking a
chemical uncoupler, 2,4 dinitrophenol is popular
among bodybuilders. No need for all that pesky
travelling. |
|
| |
of course, having a foot chopped off due to frostbite
will also result in rapid weight loss. |
|
| |
Depends on whose foot it is, and on who eats it. |
|
| |
[bs0] is that true about 24DNP? |
|
| |
Presumably an intermediate for DNPH, which is MUCH more interesting in terms of physical properties ... |
|
| |
Giving entirely new meaning to the term 'explosive
diarrhea'. |
|
| |
//Yes, that was odd - they ate the livers of their dogs (the poisonous bit), but didn't eat the rest |
|
| |
Let me guess, public school..get some funny habits in them places.. |
|
| |
I got bored and read a book on it. The author pointed out the lack of fuel oil in the dump they'd left behind, for the return trip. |
|
| |
The washers sealing the containers dried out or something, so they had no way to heat food (some free calories there) or melt snow for water, which along with everything else, didn't help. |
|
| |
It is. The Wiki page has some reasonable info. Also,
just came back from a conference where neuronal
degradation was slowed by low level dnp, reduced
mito ROS and apoptosis the mechanism in their
model, although behavioral studies still outstanding. |
|
| |
//neuronal degradation was slowed by low level
dnp// |
|
| |
That does surprise me. I would have assumed that
uncoupled cycling in mitochondria would just
increase the levels of free radicals and other stuff. |
|
| |
well, both ROS production and mito Ca2+ accumulation are non-linear with membrane
potential. |
|
| |
You mean that if you uncouple, and thereby drop
the membrane potential, you reduce ROS formation
disproportionately? |
|
| |
Yes, a slight fall in membrane potential say from
180mV to 160mV pretty much abolishes ROS
formation. Incidentally, ATP synthesis is already
maxed out at about 140mV so an artificially-induced
or UCP-induced proton leak of just the right amount
could be considered to be desirable. However, the
ROS formation, at least in normal physiology is used
to tune the Ca2+ and other signalling machinery....
so (as usual) it's more complex than we first thought. |
|
| |
//it's more complex than we first thought.// |
|
| |
Isn't that just always the way? But I wonder why we
(and presumably all other species with
mitochondria) have evolved a higher and apparently
more polluting membrane potential than is needed
for ATP synthesis? Is it just the old chestnut of
evolution not caring about long-term damage, or is
there a reason? |
|
| |
I'd bet on there being a reason. My personal bet:
Ca2+ release fills the mitochondria, membrane
potential is depressed, ROS production suppressed,
the IP3 receptor becomes reduced (less sensitive
form), immediate Ca2+ signals are made less likely at
an individual mitochondria/ER contact site. ROS is
acting as a local signal to tune Ca2+ release. |
|
| |
Ah - that all gets too pathway-ish for me, but it
sounds plausible. But you're saying the ROS is there
to keep the IP3 receptor oxidized? |
|
| |
Sounds like an unintelligent design to me. A bit like
using the soot coming out of a diesel to regulate the
throttle (only completely different, of course). |
|
| |
I'd think of it the other way around, the ROS is telling
the IP3R that there is an active mito nearby that's
kicking it's heels. The mitos being the biggest Ca2+
sink by far, it could be considered sensible to have
one ready before you go flooding the cytosol with
Ca2+ and precipitating all your phosphate... |
|
| |
wow, who would have known how simple cells and pathways are; it's not rocket surgery. |
|
| |
Ah, OK. But do the mitochondria always run at a
high (?180mV) membrane potential? Or does it drop
when there's a big demand for ATP? |
|
| |
(Stops and realizes how little he knows about this
topic.) |
|
| |
to the library with you..... |
|
| |
So, do Dihydropyridine-derived CCB's impact mitochondrial activity ? |
|
| |
//to the library with you.....// |
|
| |
It's cheating if you read the literature. |
|
| |
As far as I know they work only on the plasma
membrane localized voltage-gated Ca2+ channels, L-
type from memory, CaV 1.1-1.4. The mitochondrial
transporters that are voltage dependent (VDAC) are
completely unrelated. So I'm gonna say "no, not
directly". |
|
| |
Fair enough. They're going to impact the population of Ca2+ in the plasma, so yes, an indirect effect only. |
|
| |
// Yes, that was odd - they ate the livers of their dogs (the poisonous bit), but didn't eat the rest. // |
|
| |
They weren't Japanese, were they ? |
|
| |
// The washers sealing the containers dried out or something // |
|
| |
The containers were made of tinplate, the joints sealed by a lead-tin solder. Unfortunately for them, at low ambient temperatures tin changes its allotropic form, from "white" to "grey" <link>. This commonly called "tin pest". There is evidence (not conclusive) to suggest that the seams of the tins fractured due to crystalline changes in the solder or the tinplate itself. |
|
| |
A welded steel container would not have been vulnerable to such degradation. |
|
| |
//sealed by a lead-tin solder.// But according to
the link, only fairly pure tin is susceptible to tin
pest. |
|
| |
What I find more amazing is that, according to the
link, the low-temperature allotrope of tin is non-
conductive, even though it is (as I understand it)
still pure tin. |
|
| |
// only fairly pure tin is susceptible to tin pest // |
|
| |
Like, perhaps, the thin layer of pure tin used to plate the ferrous metal of the cans, and to which the solder adheres ... ? |
|
| |
And begorrah if it isn't right you are. |
|
| |