1

Chemistry / Can solutes migrate out of water?

« on: 08/03/2024 11:30:11 »

Hello!

I am quite confused with the so-called solid hydrogels. These are supposed to be quite solid materials but with very high water content. These are also not swellable which I suppose it means they do not absorb additional water like sponges. However they don't seem to behave the way I am expecting.

Let's say, we take a solid hydrogel material and put it contact with a water solution of a solute. Upon contact, the solute should migrate via diffusion from the water solution to the hydrogel right since both contain water and since they touch each other.

However, for some strange reason this does not seem to be the case. It may be that the mere contact of the solid hydrogel and the water solution is not enough to allow the solute to migrate via diffusion. Or some other reason, I don't know.

I am basically looking for a solid-like material that when I put it in contact with a water solution, it will get filled by the solute via diffusion without having to absorb water. So basically, I want to migrate the solute from the solution to the material without bulk migrating any solvent (of course the solvent can still migrate via diffusion as the solute but the net bulk move would be nil, i.e. the material will not increase its water content).

Any idea on that?

Thanks!

2

Chemistry / Re: Are there gel-like and solid-like materials with high diffusivity?

« on: 03/12/2023 02:15:18 »

Thanks but I think you confuse absorption with diffusion?

3

Chemistry / Are there gel-like and solid-like materials with high diffusivity?

« on: 01/12/2023 22:59:00 »

Hello!

Are there gel-like and solid-like materials that when they touch (or be immersed into) a water solution, will allow solutes from the water solution to migrate and diffuse into them?

Thanks!

4

Chemistry / Re: How to estimate time until concentration equilibrium?

« on: 24/07/2023 20:46:39 »

@scientizscht

pi = iMRT ?

Thanks but where is time? 🤔

5

Chemistry / How to estimate time until concentration equilibrium?

« on: 19/07/2023 00:10:14 »

Hello

If I have two containers, one with a solution and another with plain water and I connect them with a tube, when will they reach same concentration?

Is there a simple (non differential) equation to calculate that time?

Thanks!

6

General Science / How to kill, both natural and medical, aerobic bacteria in the gut?

« on: 01/06/2023 11:51:55 »

Hello

Is there a way, both natural and medical, to kill aerobic bacteria in the gut?

I think bloating is caused from these and I would like to know how to kill them. I know Rifaximin is killing some that cause ammonia.

Please note: this is not seeking medical advice, just scientific evidence/opinion

Thanks!

7

General Science / How does ChatGPT work?

« on: 21/04/2023 09:56:27 »

Hello!

Obviously ChatGPT is something unprecedented from the machine learning sector.

Do you follow these advances closely to explain what is actually happening?

Is it simply training statistically a model so that it can put together words that make sense? I am trying to figure out if it is something more than that, because it can be quite advanced in its responses though I do not see much of originality of course.

Thank you!

8

General Science / How do anti-snore pillows work?

« on: 04/02/2023 12:11:26 »

Hello!

How do anti-snore pillows work? Are they really effective to be allowed to advertise something like that?

Thanks!

9

Physics, Astronomy & Cosmology / How do thermoregulation fabrics work?

« on: 05/12/2022 02:48:35 »

Hello!

How do thermoregulation fabrics work?

What are the various mechanisms of action available?

Thank you!

10

Physiology & Medicine / How they predict population declines?

« on: 22/09/2022 23:14:07 »

Hello

How can the estimate a graph like this? You can see they claim that the France population will plateau by 2040 and start declining afterwards. There is absolutely no French historic trend like that. Any idea how they can come up with such prediction?

https://worldpopulationreview.com/countries/france-population

Thanks!

11

Chemistry / Re: Is there a way to infer the maximum dilution of a substance?

« on: 06/09/2022 19:56:28 »

Realistically, someone would have to do the experiment (unless it has already been done).

Yes of course, just wanted to ask if anyone had similar experience or even what is the maximum concentration of an analogue substance e.g. a protein? Just looking to get an indication of magnitude.

12

Chemistry / Re: Is there a way to infer the maximum dilution of a substance?

« on: 05/09/2022 21:24:43 »

Oh sorry yes I meant concentration. Also particles are not hollow. Any hints?

13

Chemistry / Is there a way to infer the maximum dilution of a substance?

« on: 01/09/2022 23:51:00 »

Hello

Any idea what would be the maximum dilution of a powder of 50-200μm particles with density 0.5g/mL?

Any even rough estimate? I am wondering if 1 gram can be easily diluted to 1 gram of water and the solution can be usable in terms of reactivity and diffusivity?

Thanks!

14

General Science / Re: Is there any quick Probabilities tutorial?

« on: 21/08/2022 15:51:08 »

Thanks, what about the probability of sequential events?

I assume rolling dices three times one after the other, would be very rare to return 111 and more probable to return something more random like 351

How would such concepts call? Will they be in most tutorialls?

15

Physiology & Medicine / Re: What is protein priming?

« on: 21/08/2022 15:45:25 »

Sorry for lateness as I am struggling with long covid.

I am asking about it as a general phenomenon/definition.

If this applies to the particular covid situation, I would assume it should not be that different from the general definition?

16

General Science / Is Stokes Law a vector equation?

« on: 21/08/2022 15:42:09 »

Hello

Is Stokes Law a vector equation orr a scalar?

Wikipedia seems to present it as scalar.

Thanks!

17

General Science / Is there any quick Probabilities tutorial?

« on: 07/07/2022 11:24:51 »

Hello

Is there a good quick tutorial on probabilities?

If you combine two independent events with an AND condition you multiple their probabilities.
If you combine two independent events with an OR condition you add their probabilities.

However, if you roll a dice, there is a 1/6 chance to get number 6. If you do get a 6, next time when you roll a dice will it again be 1/6 probability? What about 1,000 times?

Are there also any other concepts that are very common/funtamental and should know?

Thanks!

18

Physiology & Medicine / What is protein priming?

« on: 21/06/2022 23:38:37 »

Hello

What is protein priming?

Thanks!

19

Chemistry / Re: KM, Turnover, kcat/KM values: how to translate them into reaction rate?

« on: 11/06/2022 22:45:23 »

Thanks, it is indeed homework-like but I am not in format education anymore.

I am just looking for the equations or one of these nice online calculators if they exist.

The challenge I face are:
1) choose the right property
2) find the right equation as I mostly find definition equations (ok I suppose that is a starting point)
3) navigate the definition restrictions (e.g. kcat/KM seems to work only in specific relative concentrations)
4) as you pointed, find the right units because I need absolute conversion rates e.g. moles per minute or grams per minute and not something relative (at least without knowing how to link it)

The stoichiometry is first order, ie. one substrate converted by one enzyme to give one product (and another one but ok). Now if this happens in one step or multiple is something I don't know but I can bare that approximation.

20

Chemistry / KM, Turnover, kcat/KM values: how to translate them into reaction rate?

« on: 11/06/2022 02:35:13 »

Hello!

I know for an enzyme the below as well as the stoichiometry of the reaction:
1) KM Value
2) Turnover Number
3) kcat/KM Value

I need to know how much substrate will be converted per minute for a given substrate concentration.

Which is the right value/number to use and how?

Thanks!