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[Music]

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[Applause]

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so I'm going to talk about molecules are

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a bit more complex than what Maksym

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which is talking about but using the

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same kind of processes to form them so

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while I was interested in that first is

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because we know that for several decades

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lab experiments have shown that the

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photochemistry are very simple ices such

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as water methanol co co 2 CH 4 NH 3

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leads to the formation of very complex

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molecules such as amino acids and

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amplifiers and some nuclear bases - so

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there's a lot of work had been done that

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different labs and what we're trying to

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simulate in the simulations is to to

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like simulate the the conversation of

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volatize like Isis such as methanol

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water etc encore grains and it radiates

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them with photons sometimes electrons

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and we see that this induces very

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complex chemistry in this Isis and leads

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to the formation of very complex

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molecules and what is interesting at the

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same time is that all those molecules

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have been seen also in me right so if

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you analyze carbonaceous meteorite such

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as Murchison you see a lot of the same

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kind of compounds like amino acids and

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Fugue molecules nuclear bases and one

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the one family of Markey that was left

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out for a long time in the lab at least

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was the sugar derivatives and so George

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Cooper in 2001 published this paper and

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where he found a lot of sugar

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derivatives in Murchison and marry me

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right and as you can see here actually

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what he found is like only one very

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small sugar in a lot of sugar

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derivatives such as sugar alcohol and

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sugar acids are also a lot of other

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things that we talked about maybe later

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but until very recently until I started

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to actually start to figure out how the

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way to to search for this sugar

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derivative in in the lab it was not

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something very common and I will explain

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why right after and

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after that other people got interested

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in that and Kannada is here found ribose

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in in in one of those lab experiments we

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should talk about that also later and so

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the reason why it's very complicated to

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do for sugars into this residues is

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because these videos are made of a lot

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of very different molecules very complex

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molecules and sugars themselves you have

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a lot of different possibilities you can

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go this is only from like three to six

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carbon atoms you can see how many

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different sugars you have and I'm only

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showing one enantiomer to music you have

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also like the the mirror image of all

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these two this is another view of the

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same molecules and just to show this is

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the only one that was found in

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meteorites but also you also have like

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so sugar acids when you replace the

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terminal carbon here by a carboxylic

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acid group and if you replace it with

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another alcohol group here you have all

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the sugar alcohols and again you

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multiply that by two and because you

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have two innocuous for almost all of

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those something very difficult to that

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sugars can exist in like linear form

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about so in cyclic forms either like

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five carbon rings or like six carbon

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ring so you also not apply that again so

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you can imagine how complex it is but so

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I try to find a method so we can still

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see these molecules and see if we can

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compare with what we found in meteorites

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so we do that in the lab using a vacuum

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chamber where we go down to pressures

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about like ten to the minus eight tours

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and we cool down a substrate down to

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about 10k and we deposit gases that we

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premix ahead of time and we deposit them

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on this cold substrate and form ice

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films that we're going to irradiate with

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a hydrogen lamp that emits photons like

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lime and iPhone photons and other

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photons in the h2 transition range so as

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you can see it's very pretty

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lamp

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and actually we spend hours staring at

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it every time we make it it's so pretty

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so pretty so for this experiment we did

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something very simple we just mix water

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in methanol because we know there are

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very abundant in Astrophysical

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environments as Maxime just talked about

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and so we departed them on a substrate

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at a 10 K and we're ready with this

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beautiful lamp for about 20 hours and

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after we we are done with the radiation

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we warm up to room temperature and we

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recover what is left on the substrate

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which is a molecule of residue and we

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analyze that with chemical techniques so

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that gas chromatography with different

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methods here so one of the first

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experiments I did I just mix a water in

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methanol in a two-to-one proportions and

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you can see this is the chromatograph we

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obtained so we just separate basically

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all the compounds inside of this

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complicated mixture and we could

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identify a few compounds in this

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chromatogram those are all the sugar

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alcohols from three to five carbons here

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and you can see also that the in the

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abundance of those compounds decreases

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with the with the size of the compound

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and if you look at the smaller features

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you can also see that we can have some

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sugars here three and four carbon and a

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few sugar acids if you summarize that in

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a table you can see that in this very

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simple experiment with just water and

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methanol you can make a lot of sugar

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alcohols which are the most abundant

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compounds and then a little bit less of

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sugars and less sugar acids this is not

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what we see in meteorites in meteorites

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we see a lot of sugar alcohols and we

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see a lot of sugar acids but only one

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sugar was actually identified just to

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give you a for comparison in this sample

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this number corresponds to about 109 and

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19 animals in the sample which

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corresponds more or less at what you can

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find in one gram of the Murchison

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meteorite

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so according to that table but what I

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think is going on in those samples is

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that you start with methanol and you

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start to polymerize it somehow so you

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put three together you get a glycerol

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and you can add more and more and make

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more and more complex sugar alcohols and

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if you oxidize then you start to make

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the sugars and the sugar acid so

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basically if you go from here to here

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the abundance should decrease because

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you have no steps to form those

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molecules and this is more as what I see

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in the experiments so in another

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experiment here published in 2016 where

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they found a ribose in one of these

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experiments they also kind of agree with

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what I just said because they have a lot

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of different compounds they found more

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than I did

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and if you look at this five carbon

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compounds here you have the sugar

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alcohols made in bigger abundance than

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the sugars and then the sugar acids so

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in this table then I started to think

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about what about the other part of of

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this table here can we find any deoxy

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sugar derivatives in just those residues

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and so I looked at the literature and

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see if anybody had talked about like a

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way to form for example deoxyribose

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which is the sugar of the DNA in the lab

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and I found a very old paper from 1962

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where they mix these small molecules in

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the presence of a catalyst at 50 C and

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they could make a little bit of

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deoxyribose and other people that I

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found and more written that it's a very

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complex like protocol here a very

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specific light source and also at 37 C

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and starting from ribose and arabinose

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here they could actually get rid of the

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which group here to make the oxy

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variable somehow but that's all I found

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about the formation of deoxyribose in

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non-biological like processes in the lab

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and so I look

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for the oxy ribosomes in the same kind

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of samples

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starting from water and methanol and I

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could find it so and to make sure that

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this was no contamination I did really

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do the experiments with carbon 13

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methanol and so that appears also here

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this is a comparison of the mass spectra

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with a standard and in the same sample I

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look for ribose and I found it too and

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so I could see I could confirm previous

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results also and and I could also try to

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figure out what is the relative

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proportion between deoxyribose and

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ribose in those experiments something I

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also found interesting that this these

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Peaks here correspond to something that

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we don't have a standard for so VD was

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very hard to determine what it was but

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we think it's one of its the only

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actually isomer of deoxyribose that has

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exactly the same mass spectrum George

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Cooper call it

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VOCs ILO's I don't think it's official

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but that's what we think it is and it's

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pretty cool because it's very abundant

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too and so if you measure the abundance

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of ribose and deoxyribose in every

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sample and you try to get the ratios you

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can see that it's pretty like wide it

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goes from point 2 to 3 point 3 which

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means that sometimes ribose is the most

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abundant compound and sometimes

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deoxyribose is more abundant what it

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shows is that it's very hard to to

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figure out what kind of mechanism leads

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to the formation of deoxyribose in that

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case we don't know if it's made from

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small molecules to bigger ones or from

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ribose that has lost an orange group to

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deoxyribose and probably none of the

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mechanism can be rolled out so it's

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probably a combination of different

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mechanism and I'm not sure this supports

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like a pure foremost we actually make

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mechanism because I'm pressurized to

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make sure a lot of different things so I

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also look for other deoxy sugar

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derivatives in the same samples and in

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meteorites George found a lot of deoxy

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sugar

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but I couldn't find any what I did found

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though is a lot of deoxy sugar alcohols

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with 3 and 4 carbons so all here and a

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meteorite George measured new samples

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using the same method to compare and he

250
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found a few of them 2 3 & 4 carbon atoms

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and those two were found in the in the

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residues but I couldn't find the the

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third one in my samples and also we

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couldn't find any deoxyribose or any

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like alcohol or acid equivalent of

256
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deoxyribose in the middle heads

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so to summarize the irradiation of water

258
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and methanol ice mixture leads to the

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formation of very complex molecules

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including sugar and deoxy sugar

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derivatives between e deoxyribose and

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ribose i talked about the mechanism i

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don't think it's a pure for most

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reaction and so the distribution of this

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compounds is very different from from

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what we see in meteorites and so we need

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to understand why it can be for

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different reasons because the the

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starting mixture is different from what

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the the ices are made of in in

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Astrophysical environment is one

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possibility and another possibility is

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also because those residues could be

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like altered with like aqueous adoration

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in meteorites and asteroids and lead to

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a different distribution and so we have

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to to study that in more detail so I

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would like to thank all the co-authors

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of for this work all the people who got

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involved on point and funding from NASA

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programs and you for your attention and

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if you have any question I'd be happy to

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Thank You Misha do we have any questions

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for the port so when I meant what I was

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talking about like we don't know which

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mechanism lead to that is because we

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only see the results right but it's

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probably a combination of like making

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something bigger and then destroying it

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and making it bigger again it's probably

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a very complex combination of

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destruction and formation of different

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different compounds that lead eventually

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to the formation of so in globally it

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goes to complexity but it's not a

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straight line definitely probably goes

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up and down many times all right we have

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another one here can you distinguish

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between two Prime and three prime deoxy

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ribose and if so what how do you explain

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where you only get one so I got a

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standard only for the for the two so I

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didn't have a standard for the three so

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maybe it's also there but I couldn't I

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couldn't look for it so and again it's

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like the other deoxys I love the saying

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we don't have the standard so we can

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guess and this one was very easy I guess

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to guess because it was the spectrum is

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very similar to the two deoxyribose

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before the other one I don't think we

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have the standard I like do you do I

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don't know if it exists actually just

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standard exists for the three

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deoxyribose I don't know probably

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alright last question so J snorky NASA

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Goddard your Isis or your residues are

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arguably much fresher than meteorite and

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so you may consider that the

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decomposition rate of deoxy sugars are

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far slower than

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of regular sugars there's Laura day 2005

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sorry 1995 paper that might be helpful

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so actually that's why George tried to

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analyze those new samples of murchison

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to look for deoxyribose because he

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thought also that it there would be more

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chance to find it there but but he

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couldn't like for sure said that that he

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could see it there so he preferred to

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say we did just didn't see it but yeah I