On the existence of two states in liquid water [pdf]
polymer.bu.edu
On the existence of two states in liquid water [pdf]
1–10 of 33 posts
Re: On the existence of two states in liquid water [pdf]
#2Interesting that the low end of this phase transition range coincides with the maximum safe temperature for mammals and birds. It could be that the delicate biological mechanisms we've developed over the years are highly sensitive to some of the bulk characteristics that change in this range.
Re: On the existence of two states in liquid water [pdf]
#3Interesting that the low end of this phase transition range coincides with the maximum safe temperature for mammals and birds. It could be that the delicate biological mechanisms we've developed over the years are highly sensitive to some of the bulk characteristics that change in this range.
The paper talks about this. It's not just mammals and birds, proteins in general become less stable over 60C:
"This raises the question of whether temperature-driven structural changes in water affect biological macromolecules in aqueous solutions and in particular in proteins... It was found that the temperature stability range of the protein is confined to the reversible interval 45–65°C. ... In all cases the critical temperature of the protein denaturation is very close to the crossover temperature T* observed in all the properties of liquid water reviewed in this work."
This is probably why sous vide temperature is around 60C.
Re: On the existence of two states in liquid water [pdf]
#4ELI5 please?
Re: On the existence of two states in liquid water [pdf]
#5ELI5 please?
the conclusion probably says it all?
"In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, our preliminary findings suggest that the structure of liquid water strongly influences the thermal stability of proteins. More in-depth research on the thermal stability of proteins dispersed in liquid water is needed."
Re: On the existence of two states in liquid water [pdf]
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Re: On the existence of two states in liquid water [pdf]
#7ELI5 please?
the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…
Is this why hot water from a tap sounds notably different from cold?
Re: On the existence of two states in liquid water [pdf]
#8ELI5 please?
the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…
Yes, but just what are those states? I see no explicit hypotheses. The clearest hint that I see is that the calculated dipole moment is 2.3 Ds at 0–60°C, "which is close to the value for ice", and 1.8 Ds at 60–100°C, "which is comparable to that reported for the vapour phase". Lower dipole moment means weaker hydrogen bonding, and less tetrahedral structure.
Re: On the existence of two states in liquid water [pdf]
#9Earlier quoted context omitted.
the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…
Is this why hot water from a tap sounds notably different from cold?
Most likely that's due to different amounts of dissolved air in the water.
Re: On the existence of two states in liquid water [pdf]
#10Interesting that the low end of this phase transition range coincides with the maximum safe temperature for mammals and birds. It could be that the delicate biological mechanisms we've developed over the years are highly sensitive to some of the bulk characteristics that change in this range.
The paper talks about this. It's not just mammals and birds, proteins in general become less stable over 60C: "This raises the question of whether temperature-driven structural changes in water affect biological macromolecules in aqueous solutions and in particular in proteins... It was found that the temperature stability range of the protein is confined to the reversible interval 45–65°C. ... In all cases the criti…
Although highly applicable you have to remember evolution is a thing. Proteins where there are no selective pressure to operate at high temperature are likely optimal in the ranges in that state of water. Hyperthermophiles live at 80degC and above only, they're still made of proteins. Their protein structures are highly similar to other organisms found at lower temperatures, but with modifications such as additional disulphide bonds that increases stability at high temperature. Most of these thermophilic enzymes operate very inefficiently at cooler temperatures or not at all. We already have that sort of broad insight from just looking over evolution and ecological niche.
The more interesting thing this finding has to offer is just understanding at a finer detail how proteins interact with water at all, and if there are any properties specific to each state. There might even be cool things like proteins that switch function given the water phase transition. You might find this sort of thing in chaperones related to heat shock for example.