If I were Viacom, I would have just gone ahead and sued Google for one googol (10^100) dollars.
That's right, $10,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000.00, plus court costs, of course.
In addition to making for enjoyable press coverage of the case ("Viacom Demands Googol From Google: No Comment From Google's Googleplex"), this would achieve several milestones in the world of copyright law, such as being the first lawsuit for more money than exists on earth. And the first lawsuit for more money than exist electrons in the the universe, for that matter.
This is only a guess, but I think the ripples might be caused by what are known as Stone-Wales defects, which involve a carbon-carbon bond rotating 90 degrees to convert a local structure of four hexagons into two pentagons and two heptagons. These rings prefer to form "puckered" conformations, which would explain the ripples.
I think "thermal fluctuations" as a reason for the ripples comes about because these interconversions have a high activation energy, so they are likely to occur only at "hot spots" caused that develop from random lattice vibrations. I would imagine that random thermal motion of atoms in the lattice would strain bonds with adjacent carbon atoms, and bond strain could move through the lattice, occasionally adding up to strain a bond enough to break it and form a defect. Just like the pentagons in fullerenes, these defects would provide curvature to the lattice- in the case of a graphene monolayer, evidently just enough to make the sheet "wavy," rather than enough to make it fold in on itself (or rip itself apart trying).
Once again, just a guess- I don't have access to the paper, so I don't know if the nature of the ripples is explained more fully there.
I doubt there could be quite as much of a need for smaller mass spec than there is for smaller computers, but I think applications will definitely be found for man-portable mass spec as these devices become smaller and more robust. One of these would allow for rapid trace chemical analysis in the field instead of collecting samples and taking them back to the lab (or to what before counted as "portable," an MS that could fit in a van). I think something like this would be great for lab analysis as well. In the lab I work in, there are only a few mass spectrometers in comparison to a large number of smaller, lower cost detectors like spectrophotometers and refractive index detectors.
This is because mass spec instruments are large (fairly new benchtop ones aren't nearly 300 pounds like the article states, though- maybe 100 or so) and expensive (hundreds of thousands to millions of dollars) while UV spectrophotometers are comparatively small and cheap (tens of thousands of dollars, and about the size of a toaster oven). Mass spec is also rather complex in its benchtop form- the instrument I work with also requires a gas cylinder and a vacuum pump for operation- and it requires very frequent maintenance to keep working right, particularly maintenance of the electrospray ionization source.
However, the sensitivity of a mass spec instrument is unparalleled (down to femtograms and attograms of material) and by providing molecular weights and fragment ions, is a huge aid to characterizing unknowns. As an example from personal experience, I've worked with three different methods for the detection of one particular molecule: liquid-chromatography with UV detection, LC with fluorescent detection, and LC-MS. The LC-MS method is at least 100 times more sensitive than the other two. While an instrument like this probably cannot do all the things a high-end instrument can do, it does seem like it could be an attractive option. I can definitely see more and more labs going to mass spec as it becomes smaller, more affordable, and easier to use.
The grandparent post is simply noting that the superconducting magnets used in some new tokamak-type "hot fusion" reactors require very low temperatures in order to remain superconducting- they need to to be cooled by cryogens like liquid helium. The niobium-tin wire that will make up the giant magnets for the in-development ITER facility, for example, is only superconductive below 18 Kelvin, so it will be bathed in liquid helium at 4 Kelvin. Four Kelvin in one part of the system, but the actual fusion will take place at one hundred million Kelvin, so, as the grandparent points out, it would be disingenuous to call it "cold fusion."
Question... Did you think of this idea before the back of envelopes calculations or after? Because, if after, than the bounty is already doing its thing.
An excellent point. And to answer your question, yes, my above post was pretty much a stream of consciousness thing. I was curious to see just how much energy it would take to break down carbon dioxide to carbon and oxygen as was suggested by the parent post; after doing that, it occurred to me that I should explain why plants don't require megajoules of energy to carry out photosynthesis, which in turn got me thinking about carbon fixation and catalysis. That naturally, is the true value of these types of prizes: to get people thinking and talking.
I should point out that my numbers for tearing apart CO2 above are off (should have used a bigger envelope, I guess)- I completely forgot that the formation of oxygen-oxygen and carbon-carbon bonds in the products would release some energy- though obviously this still ends up a giant net loss of energy. Using the standard Gibbs energy of formation of carbon dioxide (what I should have looked up in the first place) of about 94 kilocalories per mole, I get about 238 gigawatts instead of 950- still a significant chunk of generating capacity though. Sir Richard Branson could possibly forward me some money to help me re-learn reaction thermochemistry so I don't make similar errors in the future. Yes, I'm pretty sure that would help.
Warning: back-of-envelope calculations follow. The bond energy of the two carbon-oxygen double bonds in carbon dioxide is about 374 kilocalories per mole of carbon dioxide. At 44 grams CO2 to a mole, a billion tons of carbon dioxide (using 1000kg=ton) is on the order of 2x10^13 moles. This would require 3x10^13 megajoules of energy, which to provide in one year (31556926 seconds) would demand 950 gigawatts of power, which will undoubtedly require more than 25 million dollars to generate. This assumes perfect efficiency in the process, of course, and does not factor in any carbon dioxide released in the generation of that much power.
The reason this process works so well in plants is that frankly, that's not how it works in plants at all. While photosynthesis involves the net breakdown of carbon dioxide and water to form oxygen and glucose, it's a complex set of separate, but connected reactions, rather than just using sunlight to blast oxygen atoms off carbon dioxide. For instance, the oxygen produced doesn't come from carbon dioxide- it comes from water split by sunlight, with the help of an enzyme. The carbon dioxide that enters plants is never actually split apart- it's simply fixed into an organic molecule, and used to generate a glucose precursor. Breaking down carbon dioxide to its component elements is simply too energy intensive.
I suppose that's an idea though- if there were a catalyst that could fix carbon dioxide into an organic molecule, and do so at reasonable conditions of temperature and pressure, it might provide a useful way of recycling carbon. For example, if you could react carbon dioxide with methane to produce acetic acid, you could pull two greenhouse gases out of the atmosphere and use them to make an industrial product (and one which could be conceivably then be used as a feedstock for plastics and fuels). Currently, this process uses carbon monoxide and methanol (made from steam reforming of methane, actually), in the presence of a metal catalyst- it seems like it could be done with CO2 and methane instead. Even if the economics might not be as favorable, the benefit in sequestering greenhouse gases might be worth it.
The two proteins noted as being the current targets for flu research are hemagglutinin and neuraminidase- these are the "H" and "N" that influenza viruses are classified by (like H5N1 for the modern strain of avian flu of much concern). Hemagglutinin plays a major role in attachment of the flu virus to the host cell, while neuraminidase promotes viral release from infected cells. These have been the focus of most flu research because the body usually has strong antigenic responses to them.
M2 happens to be an ion channel protein for the flu virus, which is also necessary for propagation of the virus (it's thought to be involved breaking down the virus protein coat once inside the host cell, freeing the genetic material to be replicated). As the article notes, it tends to be more conserved than H and N- there may be a severe disadvantage for a flu virus to have a mutant strain of M2.
What the article does not mention, however, is that there are a couple of antiviral drugs already available which target M2. Amantidine and rimantidine both are thought to interfere with M2, and are already administered as antivirals against flu. (Curiously enough, they started as Parkinson's treatments- it was discovered patients taking them had serendipitous flu resistance). While a vaccine meant to target M2 might work differently than the adamantane-based antiviral drugs, it's worth noting that influenza, and H5N1 flu at that, resistant to those drugs is already quite common throughout Southeast Asia.
Three: A number, numeral, and glyph; the natural number following 2, but preceeding 4; the first unique prime; the second triangular number; integral divisor of natural numbers whose digits add up to a multiple of three.
Much of the arsenic contamination in South Asian water is of natural origin- a fact that a lot of well-meaning developmental organizations learned when they dug wells in Bangladesh. The options for water without arsenic in the region are getting it from rivers, which are becoming a much less attractive option as they are forced to support ever greater populations and industrialization, and from wells deep enough to get below arsenic-bearing sediments, which are much more expensive.
The problem with filtration is that it requires a level of centralized distribution that does not exist in many parts of the world. Either you do it from a central water treatment plant, which requires building an infrastructure of pipes and sewers, or you have to distribute filters directly to people. This makes those people dependent on their government (bad choice) or western aid agencies (really bad choice)for drinking water. The idea here is that a village could make these themselves.
I definitely agree, though, that acceptable waste disposal will become a necessity for clean water in developing nations, particularly as they become more developed. Stories of industrial waste dumped into rivers used for drinking and bathing, and of human waste trickling through open trenches down city streets sound primitive, sound foolish- until you note that the great cities of the West operated like that for centuries, and indeed the part about keeping agriculture and industrial waste out of drinking water is still an problem.
The process the MIT team used to create pleasant-smelling bacteria is pretty interesting, and might address your comment about (ahem) cat farts. They started with a strain of E. coli that had indole production genes knocked out. This is important to note, because the chemical indole and its derivatives have very strong odors. In trace quantities, it is a component of many pleasantly scented oils, like oil of jasmine.
In larger concentrations, indoles smell like feces. In fact, feces usually smell like feces because they contain indoles- 3-methylindole, for instance, also goes by the name skatole, as in "scat," for good reason. Indoles are produced in the breakdown of many natural products in the body, most notably the amino acid tryptophan and its derivatives like serotonin (coincidentally, while E. coli has a well-studied system called the trp operon for making tryptophan, we lack this, so tryptophan must be obtained from the diet). So step one in making something smell good is getting rid of processes that smell bad.
As far as the production of nice smells like wintergreen and banana, those two smells might stand out to anyone who had an organic chemistry lab course- Fischer esterification being a very popular experiment for novices. The nice smelling chemicals, methyl salicylate and isoamyl acetate (more of a pear smell, IMO) are esters, combinations of an organic acid and an alcohol (acetyl salicyate is aspirin, btw). Organic chemists use a reaction catalyzed by acid or base and heat; biology uses enzymes called transferases to do the same job. The genetic engineering that the MIT team did is here- the salicylate methyltransferase comes from a petunia hybrid, for instance, and the alcohol acetyltransferase from Saccharomyces cervesiae, a.k.a. brewer's yeast (there are some good beers out there that have a fruit odor to them, despite containing no fruit- this is how). They also had to insert a bunch of genes to allow E. coli to make precursors it would have been unable to otherwise, like salicylic acid, and others to regulate the process. The MIT team has a page covering the major elements of their "toolbox" here.
"The Academician's private residences shall remain off-limits to the Genetic Inspectors. We possess no retroviral capability, we are not researching retroviral engineering, and we shall not allow this Council to violate faction privileges in the name of this ridiculous witch hunt!"
* Fedor Petrov, Vice Provost for University Affairs
Aspartame is more than just phenylalanine. It gets its name from being aspartyl-phenylalanine-1-methyl ester. Aspartic acid and phenylalanine are both amino acids, and are both naturally found in the human body. Phenylalanine cannot be synthesized de novo by humans, however, so it must come from dietary sources. The major role it plays in the human body is conversion to the amino acid tyrosine, from which a very wide variety of biological substances are generated, particularly neurotransmitters like dopamine and adrenaline.
Some people, however, have the condition phenylketonuria (PKU), an inability to convert phenylalanine into tyrosine. For them, tyrosine becomes essential in the diet, and consumption of phenylalanine becomes dangerous, because phenylalanine and its breakdown products will accumulate, which can damage the brain (hence the warning on diet soda cans).
Also of interest in the aspartame molecule is the methyl ester on the end- in the presence of heat and acid or base, the ester bond breaks to form methanol. The enzyme that begins the process of alcohol metabolism, alcohol dehydrogenase, cannot distinguish between methanol and ethanol, and so it oxidizes methanol to methanal, better known as formaldehyde. Two things to keep in mind about this process: there are other natural human metabolic processes that also produce methanol, and aspartame is 180 times sweeter than sugar, so there is not very much at all in diet soda. For some people, the health effects of aspartame are certainly real, and they should avoid it- in my personal case, though, I consider sugar to be more dangerous in the long run.
The journal article doesn't seem to be up on the site for Nanomedicine yet, but the same group's prior research on protein scaffolds (also referenced in the news article) may provide some answers.
The proteins they use are structurally very similar to natural silk, which is composed of proteins arranged primarily in a beta-sheet conformation. This conformation lines up strands of amino acids in a rough plane and cross-links them, usually with hydrogen bonds, but sometimes with ionic attractions or hydrophobic interactions.
The use of spider silk for clotting wounds has been known since ancient times; coagulation basically requires the onsite formation of a sticky, fibrous protein mess, and spider silk is almost completely sticky, fibrous protein (and unlike many similar foreign substances, doesn't provoke a dangerous immune reaction). This protein gel is basically the same sort of thing, but with the neat added trick that the cross-links are the result of ionic interactions, so that you could have an anhydrous powder of this stuff that you sprinkle onto a wound, and when it contacts electrolyte-rich bodily fluid (their paper on peptide nanofiber nerve scaffold notes it only requires normal physiological concentrations of salt, like those in saline or spinal fluid- from the news article, that's not especially clear), it turns to a fibrous gel.
As far as whether it promotes healing, interestingly enough, clotting itself promotes healing- the clot
itself stimulates the cells in charge of repair- really, the sooner a stable clot is formed, the sooner your own cells can start fixing the damage. In the neural scaffold paper, the group also points out that, being composed of just the same amino acids ubiquitous in the body, the scaffold can be safely broken down to amino acids and then metabolized or excreted; I would imagine the same would be possible for the clotting gel when it is no longer needed.
Them: "Our people have spent generations traveling the void of space in order to reach the fabled Earth, home of our greatest god. Take us to the Almighty Yahoo!"
Us: "Should we tell them that Google bought their god 900 years ago?"
The "cloverleaf," or cross shape which is indicative of tRNA is only its secondary structure- the 3D form it assumes in vivo looks more like an "L" shape, as seen here.
Have you tried the Constitution? It's in Article I- Section 2 for the House, Section 3 for the Senate.
No person shall be a Representative who shall not have attained to the age of twenty five years, and been seven years a citizen of the United States, and who shall not, when elected, be an inhabitant of that state in which he shall be chosen.
No person shall be a Senator who shall not have attained to the age of thirty years, and been nine years a citizen of the United States and who shall not, when elected, be an inhabitant of that state for which he shall be chosen.
The mechanism (or set of mechanisms) is a limit on how many times a non-gamette cell may replicate.
This is known as the Hayflick limit, and is related to what the great-grandparent post brought up- telomeres. When normal differentiated cells divide, an issue with the way our DNA polymerase works causes a bit off the end of the DNA strand to not be replicated- your DNA gets shorter with each cell division. To counter this, there are sequences of repeating nucleotides at the end called telomeres. The telomeres are there to take the hit for your genes- with each replication, it is they, rather than coding regions of DNA, that get clipped.
As you might imagine, though, this process cannot continue indefinitely; eventually, the telomeres are clipped down to nothing, and genetic damage occurs with each division, quickly making cells no longer viable. The Hayflick limit for differentiated human cells is in the range of 50-70 cell divisions. This represents the sort of tradeoff the parent post mentions- it means adult cells cannot continuously be replenished by healthy new cells, but OTOH acts as a sort of brake on cancer- a cell that is permanently stuck in "replicate and divide" mode can reach this limit in a matter of days. So, why do we get cancer anyway? The cancer cells that go on to cause havoc are ones that have found ways around this limit. One way (the most common) of doing this is by using an enzyme called telomerase. Telomerase is a specialized type of reverse transcriptase that basically writes telomere sequences back onto the chromosome, lengthening them again.
Why don't we have this incredibly useful enzyme? We do, but the gene for it is inactivated in our differentiated cells. Cancer cells that make use of telomerase require a mutation to remove the inactivation. Or, they can simply arise from the cells which have active telomerase- stem cells. Now, a lot has been learned about the amazing properties of stem cells in the last few years, and because of their remarkable talent for repairing and rebuilding tissues, it seems very strange that your body doesn't really want many of them around- the task of the gene being mentioned here . The reason for this, as this new research suggests, may be cancer.
It may be instructive to look at the brain- for decades, it was believed that neurons didn't even get replaced at all, and it has been only in the last few years that the idea of neurogenesis from adult stem cells has been accepted. Given the seriousness of brain injury and deterioration, it would seem as though the brain would have plenty of stem cells available to repair damage. However, brain tumors are of course incredibly deadly- the five year outlook for a glioblastoma multiforme patient is about three percent. Glioblast- that's the precursor cell for the glial cells that make up most of the brain. Basically, if the body lets cells divide, it opens itself to the possibility that those cells will divide uncontrollably. So your genes are set up to make a tough bargain- you don't have enough multipotent cells available to reverse the ravages of age or certain forms of injury, but by limiting cell division as much as it is possible, your genes limit the threat cancer poses.
No, this has nothing to do with telomeres, which is what I think you're talking about. The product of the gene p16-Ink4a is a protein which inhibits an enzyme called a cyclin-dependent kinase. What this cyclin-dependent kinase does is control a "checkpoint" between two stages in a cell's life cycle. A cell at this checkpoint can either be told to go ahead and replicate its own DNA, or it can be told to just sort of "pause." Due in large part to the action of this gene, p16-Ink4a, most of your adult cells are stuck in "pause."
Your body maintains enough cell division activity to do upkeep, but obviously, there are limits to that- the slow deteriorations of age, as well as the inability to make certain repairs. If p16-Ink4a is not there to inhibit its target, the kinase it inhibits will give the "go-ahead" to the cell to replicate its chromosomes, divide, return to that checkpoint, replicate, divide, and so on. If the several cell systems whose function it is to notice this alarming occurence fail in their task (your cells have genes which try to initiate suicide in the cell if an error is detected), then the cell divides out of control- cancer. This is at the very beginning of a cancer, and all happening inside the tumor cell- the rest of your body is not on alert yet. Basically, if p16-Ink4a is working correctly, it prevents cells from ever becoming cancer in the first place. The relationship to stem cells is quite interesting as well- through the action of this gene, your body essentially makes the decision that as you age, keeping around active stem cells to maintain your tissues is not worth the increased risk of cancer they represent.
The unique failure modes of these Acme components, however, have caused IBM researchers to stumble upon a remarkable macroscale quantum effect which may be useful in the development ofquantum computers.
Apparently, when the Acme Rocket Sled, Acme Giant Rubber Band or the Acme Bat-Man suit reach their point of failure, every particle of the unfortunate user is compelled into a quantum superposition (known as the Chuck Jones state) where the particles of the user appear to exist outside of the normal flow of time, during which the user can apparently communicate with the outside using messages written on signs. The wavefunction collapses, however when the user realizes the peril of the current situation; the user returns to normal time and is contacted catastrophically by the approaching train/TNT detonation/boulder/ground/ground followed by a pursuant boulder.
IBM scientists believe that useful calculations could be made nearly instantaneously from the perspective of outside observers, if only the user inside the Jones state could be induced to work complex math problems and write the answer on a picket sign, rather than simply using such signs for messages like, "Why Me?", "Not Again!", "?!?!?!?!?!" or "Ouch."
NASA is also working with Acme to determine the physical mechanism by which the Acme Portable Hole functions.
Slashdot Mirror
That's right, $10,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000.00, plus court costs, of course.
In addition to making for enjoyable press coverage of the case ("Viacom Demands Googol From Google: No Comment From Google's Googleplex"), this would achieve several milestones in the world of copyright law, such as being the first lawsuit for more money than exists on earth. And the first lawsuit for more money than exist electrons in the the universe, for that matter.
I think "thermal fluctuations" as a reason for the ripples comes about because these interconversions have a high activation energy, so they are likely to occur only at "hot spots" caused that develop from random lattice vibrations. I would imagine that random thermal motion of atoms in the lattice would strain bonds with adjacent carbon atoms, and bond strain could move through the lattice, occasionally adding up to strain a bond enough to break it and form a defect. Just like the pentagons in fullerenes, these defects would provide curvature to the lattice- in the case of a graphene monolayer, evidently just enough to make the sheet "wavy," rather than enough to make it fold in on itself (or rip itself apart trying).
Once again, just a guess- I don't have access to the paper, so I don't know if the nature of the ripples is explained more fully there.
This is because mass spec instruments are large (fairly new benchtop ones aren't nearly 300 pounds like the article states, though- maybe 100 or so) and expensive (hundreds of thousands to millions of dollars) while UV spectrophotometers are comparatively small and cheap (tens of thousands of dollars, and about the size of a toaster oven). Mass spec is also rather complex in its benchtop form- the instrument I work with also requires a gas cylinder and a vacuum pump for operation- and it requires very frequent maintenance to keep working right, particularly maintenance of the electrospray ionization source.
However, the sensitivity of a mass spec instrument is unparalleled (down to femtograms and attograms of material) and by providing molecular weights and fragment ions, is a huge aid to characterizing unknowns. As an example from personal experience, I've worked with three different methods for the detection of one particular molecule: liquid-chromatography with UV detection, LC with fluorescent detection, and LC-MS. The LC-MS method is at least 100 times more sensitive than the other two. While an instrument like this probably cannot do all the things a high-end instrument can do, it does seem like it could be an attractive option. I can definitely see more and more labs going to mass spec as it becomes smaller, more affordable, and easier to use.
The grandparent post is simply noting that the superconducting magnets used in some new tokamak-type "hot fusion" reactors require very low temperatures in order to remain superconducting- they need to to be cooled by cryogens like liquid helium. The niobium-tin wire that will make up the giant magnets for the in-development ITER facility, for example, is only superconductive below 18 Kelvin, so it will be bathed in liquid helium at 4 Kelvin. Four Kelvin in one part of the system, but the actual fusion will take place at one hundred million Kelvin, so, as the grandparent points out, it would be disingenuous to call it "cold fusion."
An excellent point. And to answer your question, yes, my above post was pretty much a stream of consciousness thing. I was curious to see just how much energy it would take to break down carbon dioxide to carbon and oxygen as was suggested by the parent post; after doing that, it occurred to me that I should explain why plants don't require megajoules of energy to carry out photosynthesis, which in turn got me thinking about carbon fixation and catalysis. That naturally, is the true value of these types of prizes: to get people thinking and talking.
I should point out that my numbers for tearing apart CO2 above are off (should have used a bigger envelope, I guess)- I completely forgot that the formation of oxygen-oxygen and carbon-carbon bonds in the products would release some energy- though obviously this still ends up a giant net loss of energy. Using the standard Gibbs energy of formation of carbon dioxide (what I should have looked up in the first place) of about 94 kilocalories per mole, I get about 238 gigawatts instead of 950- still a significant chunk of generating capacity though. Sir Richard Branson could possibly forward me some money to help me re-learn reaction thermochemistry so I don't make similar errors in the future. Yes, I'm pretty sure that would help.
The reason this process works so well in plants is that frankly, that's not how it works in plants at all. While photosynthesis involves the net breakdown of carbon dioxide and water to form oxygen and glucose, it's a complex set of separate, but connected reactions, rather than just using sunlight to blast oxygen atoms off carbon dioxide. For instance, the oxygen produced doesn't come from carbon dioxide- it comes from water split by sunlight, with the help of an enzyme. The carbon dioxide that enters plants is never actually split apart- it's simply fixed into an organic molecule, and used to generate a glucose precursor. Breaking down carbon dioxide to its component elements is simply too energy intensive.
I suppose that's an idea though- if there were a catalyst that could fix carbon dioxide into an organic molecule, and do so at reasonable conditions of temperature and pressure, it might provide a useful way of recycling carbon. For example, if you could react carbon dioxide with methane to produce acetic acid, you could pull two greenhouse gases out of the atmosphere and use them to make an industrial product (and one which could be conceivably then be used as a feedstock for plastics and fuels). Currently, this process uses carbon monoxide and methanol (made from steam reforming of methane, actually), in the presence of a metal catalyst- it seems like it could be done with CO2 and methane instead. Even if the economics might not be as favorable, the benefit in sequestering greenhouse gases might be worth it.
I bet his machine doesn't have enough gigaquads to run that.
Perhaps the architect of glasnost should now push for "openness" in software as well?
...will be a modification to Tetris to make that damn straight-line block appear more often.
M2 happens to be an ion channel protein for the flu virus, which is also necessary for propagation of the virus (it's thought to be involved breaking down the virus protein coat once inside the host cell, freeing the genetic material to be replicated). As the article notes, it tends to be more conserved than H and N- there may be a severe disadvantage for a flu virus to have a mutant strain of M2.
What the article does not mention, however, is that there are a couple of antiviral drugs already available which target M2. Amantidine and rimantidine both are thought to interfere with M2, and are already administered as antivirals against flu. (Curiously enough, they started as Parkinson's treatments- it was discovered patients taking them had serendipitous flu resistance). While a vaccine meant to target M2 might work differently than the adamantane-based antiviral drugs, it's worth noting that influenza, and H5N1 flu at that, resistant to those drugs is already quite common throughout Southeast Asia.
Five is RIGHT OUT, however.
The problem with filtration is that it requires a level of centralized distribution that does not exist in many parts of the world. Either you do it from a central water treatment plant, which requires building an infrastructure of pipes and sewers, or you have to distribute filters directly to people. This makes those people dependent on their government (bad choice) or western aid agencies (really bad choice)for drinking water. The idea here is that a village could make these themselves.
I definitely agree, though, that acceptable waste disposal will become a necessity for clean water in developing nations, particularly as they become more developed. Stories of industrial waste dumped into rivers used for drinking and bathing, and of human waste trickling through open trenches down city streets sound primitive, sound foolish- until you note that the great cities of the West operated like that for centuries, and indeed the part about keeping agriculture and industrial waste out of drinking water is still an problem.
In larger concentrations, indoles smell like feces. In fact, feces usually smell like feces because they contain indoles- 3-methylindole, for instance, also goes by the name skatole, as in "scat," for good reason. Indoles are produced in the breakdown of many natural products in the body, most notably the amino acid tryptophan and its derivatives like serotonin (coincidentally, while E. coli has a well-studied system called the trp operon for making tryptophan, we lack this, so tryptophan must be obtained from the diet). So step one in making something smell good is getting rid of processes that smell bad.
As far as the production of nice smells like wintergreen and banana, those two smells might stand out to anyone who had an organic chemistry lab course- Fischer esterification being a very popular experiment for novices. The nice smelling chemicals, methyl salicylate and isoamyl acetate (more of a pear smell, IMO) are esters, combinations of an organic acid and an alcohol (acetyl salicyate is aspirin, btw). Organic chemists use a reaction catalyzed by acid or base and heat; biology uses enzymes called transferases to do the same job. The genetic engineering that the MIT team did is here- the salicylate methyltransferase comes from a petunia hybrid, for instance, and the alcohol acetyltransferase from Saccharomyces cervesiae, a.k.a. brewer's yeast (there are some good beers out there that have a fruit odor to them, despite containing no fruit- this is how). They also had to insert a bunch of genes to allow E. coli to make precursors it would have been unable to otherwise, like salicylic acid, and others to regulate the process. The MIT team has a page covering the major elements of their "toolbox" here.
* Fedor Petrov, Vice Provost for University Affairs
Few knew me. Then, Valve called.
Some people, however, have the condition phenylketonuria (PKU), an inability to convert phenylalanine into tyrosine. For them, tyrosine becomes essential in the diet, and consumption of phenylalanine becomes dangerous, because phenylalanine and its breakdown products will accumulate, which can damage the brain (hence the warning on diet soda cans).
Also of interest in the aspartame molecule is the methyl ester on the end- in the presence of heat and acid or base, the ester bond breaks to form methanol. The enzyme that begins the process of alcohol metabolism, alcohol dehydrogenase, cannot distinguish between methanol and ethanol, and so it oxidizes methanol to methanal, better known as formaldehyde. Two things to keep in mind about this process: there are other natural human metabolic processes that also produce methanol, and aspartame is 180 times sweeter than sugar, so there is not very much at all in diet soda. For some people, the health effects of aspartame are certainly real, and they should avoid it- in my personal case, though, I consider sugar to be more dangerous in the long run.
The proteins they use are structurally very similar to natural silk, which is composed of proteins arranged primarily in a beta-sheet conformation. This conformation lines up strands of amino acids in a rough plane and cross-links them, usually with hydrogen bonds, but sometimes with ionic attractions or hydrophobic interactions.
The use of spider silk for clotting wounds has been known since ancient times; coagulation basically requires the onsite formation of a sticky, fibrous protein mess, and spider silk is almost completely sticky, fibrous protein (and unlike many similar foreign substances, doesn't provoke a dangerous immune reaction). This protein gel is basically the same sort of thing, but with the neat added trick that the cross-links are the result of ionic interactions, so that you could have an anhydrous powder of this stuff that you sprinkle onto a wound, and when it contacts electrolyte-rich bodily fluid (their paper on peptide nanofiber nerve scaffold notes it only requires normal physiological concentrations of salt, like those in saline or spinal fluid- from the news article, that's not especially clear), it turns to a fibrous gel.
As far as whether it promotes healing, interestingly enough, clotting itself promotes healing- the clot itself stimulates the cells in charge of repair- really, the sooner a stable clot is formed, the sooner your own cells can start fixing the damage. In the neural scaffold paper, the group also points out that, being composed of just the same amino acids ubiquitous in the body, the scaffold can be safely broken down to amino acids and then metabolized or excreted; I would imagine the same would be possible for the clotting gel when it is no longer needed.
Us: "Should we tell them that Google bought their god 900 years ago?"
The "cloverleaf," or cross shape which is indicative of tRNA is only its secondary structure- the 3D form it assumes in vivo looks more like an "L" shape, as seen here.
That's pretty much what IM is like now.
This is known as the Hayflick limit, and is related to what the great-grandparent post brought up- telomeres. When normal differentiated cells divide, an issue with the way our DNA polymerase works causes a bit off the end of the DNA strand to not be replicated- your DNA gets shorter with each cell division. To counter this, there are sequences of repeating nucleotides at the end called telomeres. The telomeres are there to take the hit for your genes- with each replication, it is they, rather than coding regions of DNA, that get clipped.
As you might imagine, though, this process cannot continue indefinitely; eventually, the telomeres are clipped down to nothing, and genetic damage occurs with each division, quickly making cells no longer viable. The Hayflick limit for differentiated human cells is in the range of 50-70 cell divisions. This represents the sort of tradeoff the parent post mentions- it means adult cells cannot continuously be replenished by healthy new cells, but OTOH acts as a sort of brake on cancer- a cell that is permanently stuck in "replicate and divide" mode can reach this limit in a matter of days. So, why do we get cancer anyway? The cancer cells that go on to cause havoc are ones that have found ways around this limit. One way (the most common) of doing this is by using an enzyme called telomerase. Telomerase is a specialized type of reverse transcriptase that basically writes telomere sequences back onto the chromosome, lengthening them again.
Why don't we have this incredibly useful enzyme? We do, but the gene for it is inactivated in our differentiated cells. Cancer cells that make use of telomerase require a mutation to remove the inactivation. Or, they can simply arise from the cells which have active telomerase- stem cells. Now, a lot has been learned about the amazing properties of stem cells in the last few years, and because of their remarkable talent for repairing and rebuilding tissues, it seems very strange that your body doesn't really want many of them around- the task of the gene being mentioned here . The reason for this, as this new research suggests, may be cancer.
It may be instructive to look at the brain- for decades, it was believed that neurons didn't even get replaced at all, and it has been only in the last few years that the idea of neurogenesis from adult stem cells has been accepted. Given the seriousness of brain injury and deterioration, it would seem as though the brain would have plenty of stem cells available to repair damage. However, brain tumors are of course incredibly deadly- the five year outlook for a glioblastoma multiforme patient is about three percent. Glioblast- that's the precursor cell for the glial cells that make up most of the brain. Basically, if the body lets cells divide, it opens itself to the possibility that those cells will divide uncontrollably. So your genes are set up to make a tough bargain- you don't have enough multipotent cells available to reverse the ravages of age or certain forms of injury, but by limiting cell division as much as it is possible, your genes limit the threat cancer poses.
Your body maintains enough cell division activity to do upkeep, but obviously, there are limits to that- the slow deteriorations of age, as well as the inability to make certain repairs. If p16-Ink4a is not there to inhibit its target, the kinase it inhibits will give the "go-ahead" to the cell to replicate its chromosomes, divide, return to that checkpoint, replicate, divide, and so on. If the several cell systems whose function it is to notice this alarming occurence fail in their task (your cells have genes which try to initiate suicide in the cell if an error is detected), then the cell divides out of control- cancer. This is at the very beginning of a cancer, and all happening inside the tumor cell- the rest of your body is not on alert yet. Basically, if p16-Ink4a is working correctly, it prevents cells from ever becoming cancer in the first place. The relationship to stem cells is quite interesting as well- through the action of this gene, your body essentially makes the decision that as you age, keeping around active stem cells to maintain your tissues is not worth the increased risk of cancer they represent.
Apparently, when the Acme Rocket Sled, Acme Giant Rubber Band or the Acme Bat-Man suit reach their point of failure, every particle of the unfortunate user is compelled into a quantum superposition (known as the Chuck Jones state) where the particles of the user appear to exist outside of the normal flow of time, during which the user can apparently communicate with the outside using messages written on signs. The wavefunction collapses, however when the user realizes the peril of the current situation; the user returns to normal time and is contacted catastrophically by the approaching train/TNT detonation/boulder/ground/ground followed by a pursuant boulder.
IBM scientists believe that useful calculations could be made nearly instantaneously from the perspective of outside observers, if only the user inside the Jones state could be induced to work complex math problems and write the answer on a picket sign, rather than simply using such signs for messages like, "Why Me?", "Not Again!", "?!?!?!?!?!" or "Ouch."
NASA is also working with Acme to determine the physical mechanism by which the Acme Portable Hole functions.
-Free telescreens for everyone!
-Victory Gin makes a fine engine degreaser.
-It's the only way we can stand against the Eurasian menace- with the help of our Eastasia allies, of course.
-Newspeak is a dramatic improvement over the English language as used on the internet.
-New advances in mathematics and science may result from the re-definition of 2+2 to equal 5.
-Residents of Oceania must endure Two Minutes Hate each day; this is a major improvement over today's 24-hour cable news channels.