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New Molecule With Switchable Chirality
Nanotechnology writes: "Available here, The molecule was developed by adding copper ions to a derivative of the amino acid methionine. The investigators were then able to switch the molecule's chirality by the addition or removal of an electron. Furthermore, they found that the molecule's chirality could be switched repeatedly, and that the two forms of the molecules polarized light in opposite directions." Especially interesting is this line from The Canary Lab's home page ("Research"): "We are also scrutinizing other aspects of signal detection technology. We prepared a new polymer very similar in structure to polyaniline ... The new polymer was designed to serve as a molecular wire for attaching electrochemical sensor molecules to electrodes."
If would kind of be good if the page said exactly what a chiral compound or whatever is. Does anyone know?
And what can this new discovery be used for? Any suggestions?????
(Not meaning to troll or someting, but that article wasn't very helpful)
Molecular polarity rocks!
...but what is chirality?
Is that the molecular polarity of any given molecule is directly proportional to the force exerted on that molecule by the forces of the systematic enviroment of that particular instance of the system object in question, if, that instance of course, has anything to do directly with that molecule isn't relevant to the object itself, or in fact, the molecule's relationship directly, with that instance of the object's force. To put it simply, there's no way to find equivalence between the instantial force and the molecule's property grid.
no sig
Definition:
A term used to describe a molecule which, in
a given configuration, cannot be superimposed
on its mirror image. This is in contrast to
achiral molecules which can be superimposed
on their mirror images. The two mirror image versions of
the molecule are known as "levo" (left-handed),
abbreviated "L," or "dextro" (right handed),
abbreviated "D," depending on which way they
rotate polarized light.
chiral compound
Definition:
A molecule that has an asymmetric center and can
be found in two non-superimposable mirror-image
forms (enantiomers).
Science and Biotechnology Dictionary
Simplistically a chiral compound is one which would appear different if viewed in a mirror. For example, your left hand cannot be imposed on top of your right hand as they are mirrors of each other. Your hands are chiral.
Biological molecules are (almost) always chiral and normally organisms can only cope with one version of a molecule and not its mirror.
Chiral molecules rotate plane polarised light. A molecule's mirror will rotate the light in the other direction. This is why they may have a use in "liquid crystal displays and non-linear optics".
1. a step toward optical switching, is this? :P
/. is only inhabited by trolls this weekend? Is it sunny spring in U.S. as well, or what?
2. a step toward optical computing?
3. a practical nano-level machine part.
4. nano-sized lighting effects
If there's anyone who knows more about those, I'd be happy to hear whether they're relevant.
Is it just me or is this in its digital simplicity a much clearer advancement than the Canadian light-trap earlier this week? At least I find this exact data much more trustworthy.
Obviously, it'll take a while before this will be a part of any nanofactories' product line outcomes. In fact, those nanofactories have not yet been invented either. Who cares, if it's going to take another 20-50 years or so. The future is on its way!-)
OT: how come
I think, therefore thoughts exist. Ego is just an impression.
Chirality refers to the stereochemistry of an atom, usually carbon. Carbon forms 4 bonds with things, each bond at a 109.5 degree angle (not 90!). At this angle, each atom bonded forms the corner of a tetrahedron with the carbon smack in the center, to maximize distance between each bonded substance.
If the 4 objects bonded to the carbon is different, then the carbon is said to be chiral. This means that there is a NONIMPOSIBLE MIRROR IMAGE of this compound. A good example would be your hands. Your left hand is a mirror image of your right hand, but you cannot (palm down) overlay them. So, for molecule CClBrI, 2 of the bonded halogens (Cl, Br, I) cannot overlap in the mirror image.
Chirality affects everything around us. For one thing, chiral molecules are optically active, meaning that it rotates plane polarized light, much like crystals in an LCD display. Cool thing is, say a molecule rotates plane polarized light 30 degrees clockwise. It's mirror image molecule (remember, these things come in pairs) will rotate it 30 degs counterclockwise.
Biological activity is also governed by chirality. Sugar, for instance, is chiral (take karo syrup and 2 polarizing filters and play with it if you don't believe me). alpha-D-Glucose (one of the two sugars that form common table sugar, the other is alpha-d-FRUCTOSE) rotates light clockwise (I believe), and upon polymerization it forms starch, which we humans have an enzyme (also chiral) that can break it down. There is another form of glucose that rotates light counterclockwise called beta-D-glucose, and when that forms *CELLULOSE* upon polymerization. Because our enzymes are chiral, it will cleave starge (alpha polymer) into glucose, and we can digest it, but it won't cleave the beta polymer (cellulose). Termites and cows have a bacteria in their stomach that will synthesise the mirror image enzyme that will cleave the beta polymer, hence, they can eat cellulose, we can't.
There are very cool implications to this. First of all, virtually all drugs are chiral, and in synthesis we have to perform isolation. Isolation of chiral substances often involves chromatography, and the chromatography column packing material to resolve chiral compounds are often (you guessed it) chiral. Improvement made in separation techniques will give better catalysts and better synthesis options, which in turn opens up new bio and non-bio synthetic techniques towards new material. Optical activity is used for LCDs, so potentially this could be used in LCD display (though the impact here is not that great, there are existing material that can fit this bill). Other potential applications include the possibility of using this in a electro-optical computer system.
Uuh, I cannot make sense of this. I would have moderated it down as "nonsense" or whatever.
I think, therefore thoughts exist. Ego is just an impression.
Nice explanation, but one thing...
The alpha and beta forms of a hexose sugar can have the same chirality - in your example, they do (D). Alpha and beta denotes which "shape" the molecule is - a glucose ring can exist in two forms, which look like a "boat" and a "chair" respectively, depending on which way you "fold" the straight "glucose" molecule
You are right about the direction the molecules rotate light - D = dextro = right = clockwise, L = laevo = left = anticlockwise (counterclockwise for all you Americans).
The two enantiomers of a chiral (asymmetrical) molecule are identical in every respect, except that they are mirror-images of each other. Call the two enantiomers of this particular molecule L and R. If you add an electron to L you get L-plus-an-electron (call it L+e) which by definition cannot be any less stable than R+e - in other words, the flip from one to the other simply can't be caused by the addition of the electron by itself.
I'm sure that these research findings are genuine but they've been edited into meaninglessness in order to make a press release - rather like the recent "space is flat" story, which, by the time it was "explained" for the general public, made no sense at all. The rules of editing press releases are:
One thing that might have been omitted:
Anything like that does give the possibility of an electron causing a symmetry-flip, because you're not flipping a whole system, just one part of it, and there's nothing to stop a system where one part only is flipped being significantly different from one where it isn't. The system consisting of two left gloves is about as valuable as the system consisting of two right gloves (system flipped as a whole) but a lot less valuable than the system consisting of one left and one right glove!But I wish someone would get hold of the real information and fill in the gaps...
I am assured that this mr. Valloppillil pretender is but a troll, but what the heck, it's always better to have a chat by the bridge than to go out and burn in sunlight.
A fine troll it seems, however, to gather positive moderation!
Simply put, your over-long sentence does not parse. I'll break it down:
"...the molecular polarity of any given molecule is directly proportional to the force" -
Excuse me, which "force"? What kind of a "force"?
"- exerted on that molecule by the forces of the systematic enviroment of that particular instance of the system object in question"
Sentence this long does not sense make.
Specify "systematic environment"
Specify "particular instance"
Specify "system object"
Specify "question"
"if, that instance of course, has anything to do directly with that molecule"
What does "of course" refer to?
"that instance" seems to refer to the previously mentioned "particular instance" of "system object." However, "system object" remains unspecified.
"the molecule's relationship directly, with that instance of the object's force."
What do you mean by this?
To put it simply, there's no way to find equivalence between the instantial force and the molecule's property grid.
Specify "instantial force"
Specify "molecule's property grid"
Specify relation to the first sentence
Specify relation to changing chirality of a molecule?
Why couldn't Microsoft have made NT a multiuser/multitasking version of MS DOS ?
Why would/should they? On the other hand, isn't it?
I think, therefore thoughts exist. Ego is just an impression.
So it seems to be, indeed
I think, therefore thoughts exist. Ego is just an impression.
This is a classical example of a collision of two different worlds with two very different sets of interest: slashdot vs. science. Let me elaborate.
One of the less original ideas, though, is the announcement of a new type of memory. Anything can be sold to the public as a new memory. I have seen so many proposals for new types of memories come and go that I'll believe them when I see them.
These new chiral molecules do have special applications, I cite their website:
That's all right, but is it really a story for slashdot?
I am not too sure on this, but weren't the accidents with Thalidomide in the 70's caused by the fact that while one of the enantiomers was an efficient curing drug, the other one caused gross birth defects if the drug was taken by a pregnant woman?
This shows the importance of separating enantiomers. This is a difficult but vital process in the "fine" chemical industry.
It's alst interesting to note that, upon death,many of the right-handed chiral molecules in our bodies convert into their left-handed complements.
"When the indicator says you're out of oil, should you continue driving anyway?" - TMBG
In my ochem class we were calling pairs of enantiomers R and S, after the latin right and left (rectus and sinister). But everyone here seems to be using L and R, so I was just wondering what the rest of the world calls enantiomers.
Liquid crystal displays utilise a feature of liquid crystals in that they line up differently when a voltage is applied, and this twisted alignment causes polarised light passing through them to be rotated. There is a polarising filter on both sides (or on one side with reflective layer at the back so light goes through the same filter twice).
When a voltage is applied, the area appears to go black, because the light polarised by the first filter has been rotated so that it doesn't go through the second filter. Where no voltage has been applied, the light goes through as normal.
Scale this up a bit, make the areas to which you can selectively apply a voltage smaller, add a back light, print a matrix of magenta, cyan, and yellow blobs on the screen, and you have an LCD screen. The screen will be black when off because the two polarising layers are at right angles to each other, and no light gets through unless something (the liquid crystal layer) rotates the light between the two polarising filters.
You can play with this if you have an old LCD calculator, and take it apart. If you find a removable polarising filter, you may be able to reverse it and find that your calculator now does white digits on a black background.
Alternatively, you can remove it altogether, and have a calculator that only you can read (because you are wearing polarising shades).
Back to the subject at hand; Will this process make LCD panel displays easier to build or cheaper? With CRT monitor prices dropping like, errm.. CRT monitors, nothing seems to be happening to LCD monitor prices; they are still ridiculously expensive (although I'm still drooling over the prospect of getting a nice 17" LG Electronics display (Saw one at Linux Expo, London last year, and it made me wonder what it was I've been looking at all this time...))
On the other hand this does seem to be quite relevant to nanotechnology. There is an analogy in the visual system, where a pigment in the retina absorbs a photon and changes conformation (not chirality) -- this shape change ultimately triggers the neural impulse etc. The researchers do specifically mention sensors in their information, so perhaps this sort of chirality change would be useful as a detector of some sort. Or if you could bind one end of the molecule to a larger molecule like a protein, you'd have a teensy tiny lever arm. Neato.
I am quite civilized, and I should be brought a beer immediately. -- Bruce Sterling
They say they make a copper complex of the organic ligand. The removal/addition of an electron is without a doubt the oxidation/reduction of the copper center. A change in oxidation state may lead to a corresponding change in coordination geometry around the Cu atom. It's probably the case that both complexes are chiral, but that they are NOT enantiomers of each other (i.e. mirror images of each other). They may simply be two DIFFERENT chiral complexes that fortuitously rotate plane polarized light in opposite directions.
Assured by whom?
Sorry, should've been "sure", not "assured" - my English failed me there.
As for your point, I just can't read your original message so that anything understandable would come out. That led me into assuming it was a sophisticated-looking bunch of nonsense. Obviously, my limited ability of parsing English is to be blamed for this.
NT hasn't evolved around DOS because it's a branch of joint operating system project with IBM. The other branch is OS/2. Generally, you can't always take the old code/functionality if you target something very different, and I'm afraid that's the case with NT as well. As for your point about stupidity of GUI-based OS, I wholeheartedly agree.
I think, therefore thoughts exist. Ego is just an impression.
There's the material you need to make optical transistors possible. Depending on how quickly the polarization takes effect (I'm assuming damn near instantanious) we now have a way to interface electrical and optical systems together in a much more convenient way. Cisco should be eating its heart out right now - THIS will make a (near) pure optic router possible.
This cvillopillil guy is oh so obviously a troll.
Go get your free Palm V (25 referrals needed only!)
As it has already been pointed out, a chiral compound is a compound that has AT LEAST 2 different forms - both of which are mirror images of each other. In terms of organic chemistry, chirality is very important. Organic chemists define chirality to be any carbon atom that has four different "things" bonded to it. The chirality arises because these carbons are said to be sp3-hybridized, meaning that they look like tetrahedrons. This is the basis for the mirror image. In a compound with many carbons, you find all carbons which have 4 different things attachted to them (as carbon has 4 bonds) and call them chirality centers. The number of possible variations of that compound is 2^n, where n is the number of chirality centers. Chirality is important because it forms the basis for most organic reactions. For example, almost all sugars in nature are D-sugars. The reaction will not proceed with an L-sugar. (D & L just mean the different mirror image configuration). On the same note, enzymes only work with one isomer (either D or L) and so on. It isn't particularly hard to change chirality centers either.
I like food.
I am former member of the Canary lab (back when I was doing my PhD), and here is one of the first papers we published on dynamically chiral compounds: http://www.ch.ic.ac.uk/ectoc/echet96/papers/003/in dex.htm This web paper was written back in 1996, and has some animations, as well as some more background on chiral compounds (tripodal metal complexes in particular). Some of the structures need to use a plugin from www.mdli.com (ChemChime). Simple explanation: In these systems, there is equal probability of finding either conformation (left-handed or right-handed), in the systems we were working, a single point derivatization of the organic part leads to a bias towards one of the conformation w/ respect to the other, hence dynamic chiral control.
-- jmcastagnetto "Life is, don't ask", Me.
Typically, helical chirality refers specifically to the "handedness" of macromolecules such as DNA and proteins. For example, DNA is normally in its "right-handed" B form, but it can also adopt a "left-handed" Z form. The handedness of a macromolecule is determined by the screw sense of its helix, Of course, these types of chiral compounds are also optically active.
Apparently, helical chirality can also apply to carbon chains with identifiable rotational conformations as well (rotational conformations such as gauche and eclipsed...best to refer to an O-chem textbook, because I don't remember them too well.)
In either case, it isn't too far fetched to imagine that copper atoms can cause changes in helical chirality.
But my question is: is this experiment about the helical chirality of poly-dialkyl-Met chains, or the helical chirality of a single dialkyl-Met residue?
This is just the type of story that I love to see on Slashdot, simply because it is non-applicable science. I guess I'm just a helpless science geek. But your post brings up a very salient point.
/. reader. However, now that molecular and chemical computing is emerging, some dedicated chemical/biochemical moderators would really help increase the quality of the posts.
/. is techie-oriented. That's its basic function, and I learn a lot from carefully reading the in-depth technology posts and comments.
The scientific posts on Slashdot (physics, biology, chemistry, etc.) sometimes seem to be garbled and misunderstood almost to the point of complete inaccuracy. For example, check out the "Welcome to Gattaca..." article that's still in the Slashdot "Science" section and the comments about Michael's misunderstanding of his source.
Part of this problem is that most of Slashdot's readers and moderators are hardcore techie geeks, as opposed to science geeks. Thus, I may not understand everything about the "Tru64" posting, but judging from the comments, it's all accurate and in-depth. However, when reading through scientific posts, one usually has to ignore the post and go straight to the actual article itself.
Possibly, Slashdot needs to acquire some more scientific moderators, especially biology- and chemistry-oriented moderators. I see quite a few physics articles around, probably because physics has traditionally had quite a bit of application to techie fields, and thus can be quite interesting to the average
Don't get me wrong. It's by no means bad that most of
However, when it comes to science posts, I'm better off just reading the article and paying attention to the few commenters that actually know what they're talking about.
4-star general in a one-man army.
cvillopillil and Steve Woston are the same troll. You can tell by the identical writing styles, although when he trolls as cvillopillil his lure is more sophisticated. It's sort of a "good troll, bad troll" game to get people to fall for the cvillopillil version.
Moderators, please moderate all cvillopillil posts down.
The absolute COOLEST prospect of a chirality changing molecule is the polorization changing properties. If you have an electron that has 1/2 probability of being added to this molecule and use light as a transmission medium for possible further switching of the molecule down the road you could have something...
I would refer you to the cited papers, and to an old (ca March-April 1996) web article: Dynamic Control of Topological Asymmetry
In that earlier report you can clearly see the biasing of a molecule conformation by a simple metal binding event. This was detected by optical methods.
Since them, other systems have been described by the same group, redox systems (Cu for example), in which there is a very strong conformational change affecting the optical and the electronic properties of the system. And this was very reproducible and stable.
I am a former memeber of the group, when I was doing my PhD at NYU
-- jmcastagnetto "Life is, don't ask", Me.
It is not that the Copper atom changes the helical chirality, it is that upon binding the systems undergo a biasing of one of the possible helical conformations.
When you oxidize/reduce the copper atom, the system undergoes a conformational change that is still chiral, but different in geometry, and thus it generates a different electro-optical response.
For more info, look at the web article I mentioned elsewhere. It is an initial report back when I was workging on my PhD at Canary's lab.
-- jmcastagnetto "Life is, don't ask", Me.
Sounds like they came up with some new method of making a qubit. If this is the case, and they *did* actually patent it, it's another case of the patent system being corrupt. (I don't know the specific research you are referring to, but the idea of 'switching' a single atom is something that has been investigated for some time now (early 80s.)) In any case, it is amazing to see that in the last 2 years or so, quantum computing technology has gone from, "well, this works, in theory," to "damn!! it's only a 4 qubit machine, but it HAULS." I was doing some background research for a project that I worked on last semester and it amazed me that from the point in time wherein I started writing the paper to the time when the paper was completed, my research was *already* out of date. Keep in mind that there is not, as of yet, a real quantum computer, but there have been actual functioning quantum computing cores. That is to say that qubits have been made, and they interact with each other, doing calculations, and not losing data. This is a big step, and it has been made only in the last year. I haven't looked at the current research on this in the last couple of months, so I bet there is something even more impressive to say for someone who has the time/energy to go peruse Phys. Review Letters or any of the other publications that are likely to have incredibly boring but informative articles on what is currently going on.
"another case of the patent system being corrupt"
/. end up bashing patents in some way or another? I suppose it's reassuring, in an odd kind of way.
Is it just me, or does every single thread on