I haven’t directly applied the formula, but How Cold is Cold Enough? suggests that 500 years at −140 is equivalent to slightly over an hour at body temperature.
Thanks for linking to that. I was having a hard time remembering where I had read about all this stuff. From the same article:
There is one bright spot. Below −100°C, the water in biological systems is finally all frozen, and molecules can’t move to react. We use cryoprotectants that have the effect of preventing freezing, but somewhere around −135°C they all have glass transition points, becoming so viscous that molecules can’t move and undergo chemical change. While the table indicates that staying below −150°C is safe from a rate of reaction standpoint, in fact any temperature below −130°C to −135°C is probably safe due to elimination of translational molecular movement as a result of vitrification.
In other words, the effect at −135C in terms of molecules being locked in place is better than before the glass transition is occurred. I assume he means in addition to the Arrhenius effect. The main reason for cooling in a cryogen like LN2 directly is the fact that its boiling point keeps the system at a constant temperature easily at a small scale. Scaled up, keeping the temperature constant should prove less of a challenge, or at least cheaper (per unit volume) to solve.
-135 might not be cold enough. Some biological reactions persist at −140. Better not to take risks like that
I haven’t directly applied the formula, but How Cold is Cold Enough? suggests that 500 years at −140 is equivalent to slightly over an hour at body temperature.
Thanks for linking to that. I was having a hard time remembering where I had read about all this stuff. From the same article:
In other words, the effect at −135C in terms of molecules being locked in place is better than before the glass transition is occurred. I assume he means in addition to the Arrhenius effect. The main reason for cooling in a cryogen like LN2 directly is the fact that its boiling point keeps the system at a constant temperature easily at a small scale. Scaled up, keeping the temperature constant should prove less of a challenge, or at least cheaper (per unit volume) to solve.
I’m not convinced it is much of a risk. Maybe if you’re assuming thousands of years will need to pass.
Was this comment a joke? If so, I like it.