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  Topic: heavy water, from lou's back to school thread< Next Oldest | Next Newest >  
BWE



Posts: 1898
Joined: Jan. 2006

(Permalink) Posted: Sep. 12 2008,07:24   

Quote (BWE @ Sep. 11 2008,23:02)
dogdidit, after I read the article I called a friend of mine who works at Hanford as a researcher and asked him if they were letting heavy water into the columbia since I'm downstream and all. He said, "I don't know".

WHat!?

You should know dammit.

But I didn't say that. I only thought it.

The thing that made it noteworthy for me was that the QM of the atom affected the chemistry in such a major way.

Here is the online article! I googled 'science news heavy water.'

http://www.sciencenews.org/view....fferent


The interbitlitweb is neet.link

ETA: here is a bit of it:
 
Quote
The length of bonds connecting water molecules could demonstrate quantum effects and help explain some of water’s weirdness.
access
HEAVY CONNECTIONSThe distance between oxygen and the heavier deuterium in a D2O molecule in liquid heavy water is three percent shorter than the distance between oxygen and hydrogen in an H2O molecule; and the hydrogen bond (dotted) is four percent longer in heavy water than in light. Click image twice for a larger view.J. Korenblat/Science News

Heavy water is not just heavier. Swapping each H in H2O with a D — hydrogen’s isotope deuterium — changes many of water’s properties. Heavy water is poisonous, and its freezing point is 4° Celsius, instead of 0°. Those differences may reveal that quantum effects rule in ordinary water, researchers have now found.

The results, reported in an upcoming Physical Review Letters, could shed light on quantum theory’s relevance for ordinary water, which is the medium for most of the action inside living cells. The work could also help explain some controversial findings on how biological molecules behave in water.

 
Quote (BWE @ Sep. 12 2008,03:20)
Also, if this turns out to be repeatable:
   
Quote
Rübhausen says the difference in bond lengths could help explain some surprising results he and his collaborators reported last year. His team was comparing RNA made with ordinary organic molecules to RNA made of those molecules’ mirror images. Their goal was to shed light on why life always uses one type of molecule rather than the other.

Chemically, the molecules and their mirror images should be identical. But the researchers found small differences in the energy it takes to excite electrons in the two types of RNA — but only when the RNA molecules were suspended in ordinary water. When the researchers repeated the experiment in heavy water, the differences disappeared.


It will quite possibly be very important.



 
Quote (Louis @ Sep. 12 2008,04:40)
 
Quote (BWE @ Sep. 12 2008,09:20)
Also, if this turns out to be repeatable:
   
Quote
Rübhausen says the difference in bond lengths could help explain some surprising results he and his collaborators reported last year. His team was comparing RNA made with ordinary organic molecules to RNA made of those molecules’ mirror images. Their goal was to shed light on why life always uses one type of molecule rather than the other.

Chemically, the molecules and their mirror images should be identical. But the researchers found small differences in the energy it takes to excite electrons in the two types of RNA — but only when the RNA molecules were suspended in ordinary water. When the researchers repeated the experiment in heavy water, the differences disappeared.


It will quite possibly be very important.

I'd be careful with this. RNA is big, I'd have to check the original data out to be comfortable with what is being claimed. Is that from the above linked stuff, or do you have a reference for it? I'm dead interested so lemme have a look!

When you have large molecules with large numbers of asymmetric centres (and planes and axes and tertiary structure etc) it is very, very, VERY hard to confirm that you have each asymmetric element perfectly opposed in your enantiomeric partner molecules. Sure, optical rotation, circular dichroism and complex NMR experiments etc can give you a huge amount of information about molecular symmetry. It's even possible they've synthesised short RNA pieces (or even large ones) from different chiral pools of molecules and made sure that no other stereoisomers crept in (practically impossible to do 100%, but not too bad at 99.9%!) and got X-ray structures. Even then remember that they are dealing with billions of billions of molecules in each sample, racemisation of asymmetric centres is a spontaneous process.

It could be some solvation effect with heavy water, it could even be due to exchange processes at labile hydrogens.

ARGH! I'm going to have to go and look this up now aren't I? Thanks BWE, like I need MORE excuses to hunt through the lit for entertaining science. ;-)

Louis



Paper it refers to:http://rnajournal.cshlp.org/cgi/reprint/13/11/1877.pdf

 
Quote (Albatrossity2 @ Sep. 12 2008,07:13)
Besides the discrete effects on individual reactions, deuterium (in water) has interesting effects on whole organisms. One of the more well-studied effects is the ability of heavy water to slow down circadian rhythms, which are fairly resistant to manipulation by lots of other chemical and physical agents. Here's a classic paper in that area.


--------------
Who said that ev'ry wish would be heard and answered
When wished on the morning star
Somebody thought of that, and someone believed it
Look what it's done so far

The Daily Wingnut

   
Wesley R. Elsberry



Posts: 4807
Joined: May 2002

(Permalink) Posted: Sep. 12 2008,07:40   

The reactors (all except one) operating on the Hanford reservation during WWII and following years were constructed as single-pass systems. Water came in from the Columbia River, got filtered, ran through the reactor, spent some short time in retention ponds, then was returned to the Columbia. AFAICT offhand, deuterium was not a factor in the design of these reactors.

--------------
"You can't teach an old dogma new tricks." - Dorothy Parker

    
BWE



Posts: 1898
Joined: Jan. 2006

(Permalink) Posted: Sep. 12 2008,07:58   

Quote (Wesley R. Elsberry @ Sep. 12 2008,07:40)
The reactors (all except one) operating on the Hanford reservation during WWII and following years were constructed as single-pass systems. Water came in from the Columbia River, got filtered, ran through the reactor, spent some short time in retention ponds, then was returned to the Columbia. AFAICT offhand, deuterium was not a factor in the design of these reactors.

Well, ok. I feel marginally better.
But things like this:
http://www.nukewatch.com/Quarterly/20053fall/page3.pdf

still have me a bit uneasy.

--------------
Who said that ev'ry wish would be heard and answered
When wished on the morning star
Somebody thought of that, and someone believed it
Look what it's done so far

The Daily Wingnut

   
Wesley R. Elsberry



Posts: 4807
Joined: May 2002

(Permalink) Posted: Sep. 12 2008,08:03   

I worked at PNL for a couple of years, though not on anything related to the Hanford Reservation. It's impossible to live in Richland without having some exposure to the issues of the Hanford Reservation, though. Occasionally, the main drag through town would be shut down for the transport of something like a submarine reactor core headed for the HR.

"Downwinder" is a real term there, mostly referring to folks on the eastern side of the Columbia River in Pasco.

--------------
"You can't teach an old dogma new tricks." - Dorothy Parker

    
BWE



Posts: 1898
Joined: Jan. 2006

(Permalink) Posted: Sep. 12 2008,08:23   

I measured stuff in Willapa Bay relating to shellfish many many years ago. One of the locals claimed that the first time they found traces of radioactive seepage from hanford was when an employee got back from vacation and set off the radiation alarm. Turns out he'd been eating oysters from the bay.

For those who don't know, whatchahoosie bay is formed by the eddy of the Columbia river as it turns North into the pacific as a result of the Coriolis effect. Clockwise in the northern hemisphere and all doncha know.

ETA: I have no idea if it's a true story and I wasn't measuring radioactivity but rather parasite blooms.

--------------
Who said that ev'ry wish would be heard and answered
When wished on the morning star
Somebody thought of that, and someone believed it
Look what it's done so far

The Daily Wingnut

   
rhmc



Posts: 340
Joined: Dec. 2007

(Permalink) Posted: Sep. 12 2008,15:17   

i live down river (and over one sound) from the Savannah River Site.  there have been many accidental releases of tritium into the savannah river...the mud around here has some really strange stuff in it.  a department of natural resources biologist i once knew said they'd not eat anything that lived in that river....

http://www.cdc.gov/nceh/radiation/brochure/profile_savannah.htm

and i might live real close to a real hydrogen bomb, too.

http://en.wikipedia.org/wiki/Tybee_Bomb

ain't gummint carelessness a hoot?

  
Henry J



Posts: 4565
Joined: Mar. 2005

(Permalink) Posted: Sep. 12 2008,15:41   

tritium has a half life of 12+ years.
 
Quote
Isotope Mass Half-life Mode of decay Nuclear spin Nuclear magnetic moment
3H 3.0160492675(11) 12.33 y Beta- to 3He  1/2  2.978960

  
jeffox



Posts: 667
Joined: Oct. 2007

(Permalink) Posted: Sep. 12 2008,17:31   

Wes wrote above:

Quote
Occasionally, the main drag through town would be shut down for the transport of something like a submarine reactor core headed for the HR.


Woo hoo!  Maybe the one I watched get loaded onto our boat!

Okay, ok, ok, that was decades ago.  Still, the one we got sure worked well.  As well as it was supposed to, anyway.

:)

  
rhmc



Posts: 340
Joined: Dec. 2007

(Permalink) Posted: Sep. 12 2008,19:45   

Quote (Henry J @ Sep. 12 2008,16:41)
tritium has a half life of 12+ years.
 
Quote
Isotope Mass Half-life Mode of decay Nuclear spin Nuclear magnetic moment
3H 3.0160492675(11) 12.33 y Beta- to 3He  1/2  2.978960

cool.

it takes two days for a leak to reach the first drinking water intakes from the river....

  
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