🎓 Dr. Freemo 🇳🇱 @freemo@social.cleverlibre.org

@robryk in theory they could mix helium into air and get a trimix. But by the depths I'd use trimix I'd need pure O2 to deco safely or timely. Even with pure oxygen deco takes about an hour after 10 - 15 minutes at the bottom. To deco on just air would take forever.

@robryk well no, but if you increase the oxygen then your maximum depth due to oxygen toxicity decreases, but your maximum depth due to nitrogen narcosis increases. So to a point you can increase your max depth by increasing oxygen, but that only gets you so far.

The supply issue isnt on air at all, its on pure oxygen. So yea air is easy, no supply issue there, just oxygen supply issues.

@robryk can't, but not simply due to deco constraints (though deco would be much longer and less safe). The main reason would be nitrogen narcosis. You are limited on air by convention to about 100 feet/30 meters because any deeper and the nitrogen narcosis would be too disorienting and thus dangerous. I myself have a natural tolerance to nitrogen narcosis so I can safely handle about 160 feet on air before it becomes an issue for me, but that is already well below safety margins.

The next limit on air is oxygen toxicity. You'd be limited to about 220 feet / 67 meters on air before the oxygen would risk giving you a seizure. So while you can replace the nitrogen with either more oxygen or helium to offset the nitrogen narcosis youll still hit a limit on depth with air due to the oxygen toxicity.

The deco itself is of course a third limiting factor for doing air deco.

All that said you can go slightly into decompression limits with air and still safely get out if I wanted to do a 100 foot dive for longer than no-deco allows. But I'd be very limited doing deco on air.

A friend of mine asked me why DNA and RNA are acids. I am **not** an expert in chemistry but I did study the basics of organic chem and do dabble a bit so I wanted to share the answer here.

Simple answer: Anything that lowers pH is an acid, RNA and DNA lower pH, therefore it is an acid.

Complex answer:

Nucleic Acids are called acids because, well, they lower pH, as anything that is an acid would. pH is, in simplistic terms, the concentration (logarithmicly) of H+ ions in a solution.

A unrelated side note with acids that dont directly donate a H+, your Lewis Acids, they still increase H+ in an aqueous solution because it effects the balance of H+ and OH- dissociation of the water itself. As such the H+ measure is still accurate. However Nucleic acids are not a Lewis Acid, they are a Bronstead-Lowry acid, which means they directly can dissociate and provide the H+ ion directly in an aqueous solution. But I'll get to that.

The individual parts of any molecule can be either acidic and basic, but a molecule overall will usually be one or the other depending on which dominates, RNA is no different, there are three major components to RNA, I attached a picture to show them. The components are a phosphate group, a sugar, and a nitrogenous base (the part that encodes data, your citosine and guanine and shit). Here is the cool part, the word base when talking about the "bases" of a strand is specifically chosen as the the word because they are themselves bases (on their own they would raise pH). Similarly the phosphor group, is also acidic, this should be obvious by its similarity to phosphoric acid. It is a proton donor for the same reason phosphoric acid is a proton donor.

So the only question remaining is why does the acidic phosphor group dominate over the Nitrogenous Base? Well for starters the the phosphate group has a pkA of near 0 , the Nitrogenous Base has a pkB of around 9.8 (depends on the base), so already the phosphate group is going to dissociate more readily than the Nitrogenous Group. However RNA strands are actually far more acidic than the individual Nucleotides that compose them happen to be. The reason for this is that RNA folds back in on itself with the bases associating with each other much like two halves of a DNA strand would. This causes the bases to be on the interior of the molecule while leaving the phosphate groups all around the outside. Since the bases are not exposed to the aqueous solution they do not dissociate as readily as they otherwise would while the phosphate groups are free to dissociate. Thus the RNA exhibits significant acidic properties.

By the way the acidic nature of RNA and DNA is intentional and functionally important. It means that the pH of the solution can be adjusted to effect the charge on the nucleotides and thus move it around. In a neutral pH solution the phosphate groups will have a negative charge. This results in the phosphates pushing each other away. This in turn can cause them to line up on opposite sides with their bases facing each other as well as help to straighten out a strand's backbone.

#DNA #RNA #Chemistry #Organic Chem #OChem #OrganicChemistry #Science #STEM @Science

@mur2501 She is an invasive species, it is my duty!

@mur2501 burn it, burn it with fire!

@mur2501

If your computer monitor has an infestation of lizards in it then what those lizards eat is the least of your problems.

@stux

@pthenq1 Ok that sounds way less appealing then :)

Woman: Do you want to get married some day?

Me: Is marriage that thing where a woman lets you touch her boobies whenever you want? If so then yes.

@louiscouture waterproof devices can rarely stand a few feet at most. Hell most "Waterproof" devices cant even stay in shallow water indefinately.

We are talking 12x the pressure at surface level. It will crush anything not specifically made for SCUBA

So apparently due to covid the SCUBA on the island is limited to air, they dont have 100% and 50% O2 available right now. That really sucks, that means I cant do a deco dive!

#SCUBA

How to get Facebook to support decentralization...

#funny #joke #humour #humor @funny

@mur2501

I already developed it, its the FMO format. Its basically just an ascii text file format but where all the spaces are replaced with the ascii number '69' and it makes fart jokes whenever you hit return.

@tetrislife @QOTO

@tetrislife if by same domain you mean to include subdomains then the issues I raised are still relevant. They are relevant tot he qoto services since each one is a separate app and not all of them integrate with SAML