There has been some research into the use of nanoparticle delivery systems for treatment of glioblastoma multiforme, a brain tumor which is often both aggressive and difficult to treat conventionally. Here is an example that met with some success.
Depends on what the material of the nanoparticles is. The PEG-PLA system used in this study doesn't tend to accumulate, and in fact the lactic acid from the breakdown of PLA can be metabolized. Similarly, the drug Abraxane, already on the market, uses nanoparticles of human serum albumin. In terms of the liver and kidneys getting exposed to the released drug, yes, that is a hazard, but one that exists regardless of the delivery method. Using nanoparticles can greatly increase the solubility and bioavailability of many drugs so that less can be used.
By "UT" in my comment above, I meant simply "it" referring to the process. You're so very helpful, phone keyboard! On the subject of the process, the limiting step would likely be how much the ceramic layer could withstand before becoming irreversibly fouled. It's making pure oxygen at 1600 degrees C, conditions at which it viciously reacts with everything.
This process looks like UT actually starts with zinc oxide which gets photolyzed to produce zinc vapor, which grabs oxygen from the water to get back to zinc oxide. This process would of course not be infinitely sustainable, and eventually the zinc oxide and ceramic surface would need to be replaced, but it has the potential for minimal use of resources.
This method seems to require direct contact between the nanotubes that make up the scale's mechanism and the analyte, so this device is probably not appropriate for that task.
Despite his last name, Lambert Wilson (the Merovingian in the Matrix sequels) is French, with more French language credits than English. "Atrocious" or not, that's the guy's actual voice.
The second thing I thought: "Do not give this to my children. I'll be climbing on the roof every day"
I don't know- looks like what they've invented here is a toy that can get itself down from the roof. And land on children's heads like the reincarnation of lawn darts, but that's neither here nor there....
It would be very difficult to test DNA in the manner described in the paper- it would appear that the specific molecules chosen have a number of attributes that make them suitable for the double-slit experiment. They are fluorescent dyes, which makes them very sensitive to detection, they can be vaporized without thermal decomposition, they are neutral molecules, and they have multiple symmetries so that there isn't a preferred orientation. DNA molecules would be destroyed by the heat sources they used, and the highly charged DNA molecule is likely to interact with the atoms of the diffraction grating in a classical electrostatic manner.
Some other biomolecules might be more suitable- phthalocyanine is similar in structure to heme and chlorophyll.
The upper bound on the age of this particular star is 15.4 billion years, so there you go. OK, I understand that it's a matter of vastly different types of measurements , models, and uncertainties, but I think it's funny that the age of the entire universe has been determined to within 110 million years but we only know the age of this particular star to +/-2.6 billion years, a range that encompasses the current age of the Sun.
I was curious about this as well, since this star is an F dwarf not terribly dissimilar from our G type Sun, and the lifespan of the Sun is usually estimated at 10 billion years. I found this presentation (Powerpoint format) about the life cycles of stars that includes a rule-of-thumb formula for the main sequence lifespan of a star with respect to its mass:
Lifetime=1/Mass^2.5.
Note that lifetime here is as a ratio of solar lifetime (so a Lifetime of 1=10 billion years) and mass is in solar masses. The paper gives the mass of HIP 11952 as about 0.83 solar masses, so an estimated main sequence lifetime would be 1/0.83^2.5= 15.9 billion years, after which it would become a red giant. Not liking the odds for its planets at that time, especially the one with a 7 day orbital period. So, it probably has a long while left, though there are wide bounds listed for mass and age, so if it is actually older and heavier, it might be living on borrowed time.
That isn't the mechanism the paper is proposing. What the authors suggest is that trees uptake radon dissolved in groundwater, transpire it into the air, and that it is the radioactive decay of radon that would be responsible for the ions released by trees.
Crossing over is normally a beneficial practice for chromosomes, and is a key advantage for sexual reproduction. See Muller's ratchet for the case of deleterious effects piling up in organisms who do not use recombination to shuffle around their genes. Therefore, it generally makes sense for chromosomes to pair up, so that at each generation, offspring get a mix of ancestral genes rather than a perfect (aside from mutation, of course) clone of a chromosome from parent's set. Being able to swap homologous genes dramatically increases the diversity of offspring. The X and Y pair is an exception because it would be a problem for recombination to occur. The genes on Y are supposed to be unique to males- if some regions of Y containing them recombined with X, those male-development specific genes could be traded away in exchange for nothing, likely leading to sterile offspring. Therefore, it has been to the advantage of XY-determination organisms to have X and Y as different as possible so that there is basically no recombination. The drawback is that Y doesn't get to recombine with anything (X can still crossover with another X), so a son's Y is essentially his father's Y and grandfather's Y, though with whatever errors have accumulated. This has led to a pruning of genes on Y over time- it appears from this paper that this deletion will not necessarily go to nothing, and that a "minimal Y" may be stable for many millions of years. It does however underline that the X/Y pair is a special case, that the endpoint of the asymmetric relationship that they have is for one chromosome to dwindle to a single purpose. The Y chromosome has 19 genes: X has around 2000.
It appears to have already happened in a few species; as the Nature News article notes, a few rodents have lost their Y chromosome completely. These remain capable of sexual reproduction and also remain differentiated between male and female. In some cases, this was the result of a permanent translocation of the SRY gene to another chromosome- either Y or a somatic chromosome. In some cases, SRY is completely lost, and different genes are used for sex determination. There's really nothing extraordinary about SRY itself, a gene thought to be an accidental duplication of an existing gene on the X. It may well be the case that how an organism determines its sex simply doesn't matter enough; there just has to be some consistent system that allows for propagation of the species. There's a wide variety of successful systems out there already coexisting, and given millions more years, undoubtedly more systems would pop up. In the case of the Y chromosome, however, it was not certain that the system could reach a stable equilibrium at all- it has lost over 96% of its genes in the course of its existence, and it faces an essential problem: the long-term selection to protect reproduction by isolating itself from recombination with X also increases its vulnerability. Ironically, the Y chromosome is itself "asexual" in a way- it passes from father to son through generations without being modified by recombination. Errors tend to accumulate, deletions cannot be replaced- it's called Muller's ratchet. Eventually, XY organisms would need to make alternative arrangements or go extinct.
It would appear, however, that Y chromosomes are a bit more robust than originally thought, and may be able to continue at their present level of basic function for tens of millions of years more. Just as my own thought, one reason for this may be the presence of genes on the Y which are necessary for sperm production. A transition to another form of sex determination would require those genes to be either moved or their functionality replaced elsewhere; otherwise any Y-less males would be azoospermic and therefore the new system wouldn't get passed on.
Well, there's no specific reason to favor the XY system of sex determination over some alternative arrangement, like the ZW system in birds (females are ZW, males are ZZ). In that case, the Z chromosome is larger and has more genes than the W. On the other hand, there's really no evidence to suggest that the XY system is any worse than the alternatives, or at least worse enough to support some sort of changeover (or lead to the extinction of placental and marsupial mammals). It does make sense to let Y "rot" to a certain extent: letting Y "cross over" with X is hazardous. It leads to the possibility of producing gametes that contain X chromosomes with male-sex determining genes, and gametes that contain Y chromosomes that lack those male-determining genes. It is to the system's benefit that X and Y are completely non-homologous, even factoring in the problem of X-linked diseases. It's theoretically possible that the function of Y could be captured in a single gene. However, chromosomes are also physical structures that have to be able to be manipulated by the machinery of the cell. It's likely that there is a minimum size for that to be done without high risk of error, which means that Y is safe.... for now.
The sun's corona is intensely hot- about 1 million kelvin, much hotter than the photosphere beneath, but the plasma is very diffuse. The photosphere, the layer that appears to us to generate the opaque disk of the sun (and is the closest thing it has to a surface) is a mere 6000K, but it's 10^12 times denser than the corona. In turn, the photosphere is about one ten-thousandth of the density of Earth's atmosphere at sea level. This really skews notions of "temperature" when we talk about a star. On Earth, we're used to objects placed in a medium fairly rapidly equilibrating to the temperature of that medium. We realize that some substances conduct faster or slower than others, but overall putting something in a hot environment makes it hot.
For all but the most finicky of physics experiments, if we had pressure conditions of the density of the sun's corona, it would be "high vacuum." Very little conduction of heat from the plasma to a comet is going to take place. The bombardment by solar photons and the gigantic magnetic and gravitational fields of the sun play a greater role here than the actual material of the sun, and thus NASA can be pleasantly surprised by Comet Lovejoy's survival of its close encounter. But it's the wrong idea to picture this comet plunging into some sort of molten inferno. Of course, the sun's core is another story. 15 times denser than lead and 16 million kelvin. I'll like to see the comet that survives that.
The look of concentration on the piano player's face was great- carefully reading the music and playing the notes, when the end result sounds like it does when I sit down at a piano. I'll agree that it wasn't the worst piece of music I've ever heard. It certainly has its moments of cacophony wherever droning low notes are randomly following by a high plinking note, but I think the very fact that it is a collection of notes makes it sound like atonal music rather than true noise. Despite the lack of pattern, an expert player playing it on a tuned grand piano does a lot for the sound. Perhaps try the same composition, but instead of a piano, have someone scratching a chalkboard.
It wouldn't be so much tearing a hole in the fabric of space as making a ripple. The laser's electric field would make a wake in the sea of transient vacuum particles that prevents their instantaneous annihilation, and hopefully lets some exotic particles exist for long enough to be detected. Despite the idea that this "quantum foam" of seething virtual particles would be the fabric of space-time, the answers to where and when phenomena would be detected are most likely "in detectors just outside the laser's path" and "femtoseconds after the laser is fired" and not perhaps "in another universe" or "85 million years in the past." This is not a FOX show, after all.
Actually, far more energetic phenomena-- gamma ray bursts-- have been studied to observe the effects their travels through the fabric of space-time on the way to Earth have had, and the results have been pretty mundane. Even for ridiculously high-energy gamma ray photons, the fabric of the universe behaves as being essentially smooth and respectful of general relativity. Maybe we'll see something a bit wilder given a chance to take a closer look, but to describe "pushing some particles apart so we can see them" as "tear apart the vacuum of space" is a bit of an exaggeration.
The issue with that example is that there wasn't continuity of currency throughout that whole period. The infamous "papiermark" of 1923 was converted into the rentenmark of 1924 -at an exchange rate of a trillion to one, and then into the Reichsmark. After WWII, the Reichsmark was exchanged for the Deutsche Mark (in W. Germany at least) and that was your stable currency. The DM can even today be exchanged for euros, though I'd imagine most DM are out of circulation. The point is that other than the DM/ euro changeover, the transitions have been limited time arrangements, in one case backed with a military occupation. What came out of each was basically a new currency. You can turn in that shoebox of DM from 1994 and get crisp new euros at a rate of about 0.5 euro for each, but you can't exchange a quadrillion 1923 papiermarks for 500 trillion euro. Different money.
Stronger magnets are always going to be advantageous for a particle accelerator, so yeah, room temperature superconductors (ones that have all the necessary properties to make good electromagnets) would be a major breakthrough. However, in terms of making an accelerator like the Tevatron or the LHC smaller, there are some physical economies of scale that make
see-it-from-space rings more suitable than lab scale. Circular accelerators lose energy due to synchrotron
radiation; these losses are inversely proportional to the ring radius, so all things otherwise equal, bigger is
better. Linear accelerators don't have
this disadvantage, but they do require
a series of electric field "drivers" along their lengths that pose major difficulties
for miniaturization. Like the ring
accelerators, the trend is to go big- the
proposed International Linear Collider
would be about 40km long. Smaller
accelerators are of course useful for a number of scientific and even medical
purposes, and there are a lot of experiments that compete for beam time at the big facilities- it'd be nice to have more available. However, a giant facility has capabilities that can't be matched by 1000 facilities with each 1/1000th the energy.
Oops- everyone who pointed out that that's the west coast of Central America is probably right- I was just going off another post that listed the cities. Even knowing what's being passed over, the angles of this video (which is spectacular) disorient me and I have trouble making heads or tails of it.
Slashdot Mirror
There has been some research into the use of nanoparticle delivery systems for treatment of glioblastoma multiforme, a brain tumor which is often both aggressive and difficult to treat conventionally. Here is an example that met with some success.
Depends on what the material of the nanoparticles is. The PEG-PLA system used in this study doesn't tend to accumulate, and in fact the lactic acid from the breakdown of PLA can be metabolized. Similarly, the drug Abraxane, already on the market, uses nanoparticles of human serum albumin. In terms of the liver and kidneys getting exposed to the released drug, yes, that is a hazard, but one that exists regardless of the delivery method. Using nanoparticles can greatly increase the solubility and bioavailability of many drugs so that less can be used.
By "UT" in my comment above, I meant simply "it" referring to the process. You're so very helpful, phone keyboard! On the subject of the process, the limiting step would likely be how much the ceramic layer could withstand before becoming irreversibly fouled. It's making pure oxygen at 1600 degrees C, conditions at which it viciously reacts with everything.
This process looks like UT actually starts with zinc oxide which gets photolyzed to produce zinc vapor, which grabs oxygen from the water to get back to zinc oxide. This process would of course not be infinitely sustainable, and eventually the zinc oxide and ceramic surface would need to be replaced, but it has the potential for minimal use of resources.
This method seems to require direct contact between the nanotubes that make up the scale's mechanism and the analyte, so this device is probably not appropriate for that task.
Despite his last name, Lambert Wilson (the Merovingian in the Matrix sequels) is French, with more French language credits than English. "Atrocious" or not, that's the guy's actual voice.
The second thing I thought: "Do not give this to my children. I'll be climbing on the roof every day"
I don't know- looks like what they've invented here is a toy that can get itself down from the roof. And land on children's heads like the reincarnation of lawn darts, but that's neither here nor there....
It would be very difficult to test DNA in the manner described in the paper- it would appear that the specific molecules chosen have a number of attributes that make them suitable for the double-slit experiment. They are fluorescent dyes, which makes them very sensitive to detection, they can be vaporized without thermal decomposition, they are neutral molecules, and they have multiple symmetries so that there isn't a preferred orientation. DNA molecules would be destroyed by the heat sources they used, and the highly charged DNA molecule is likely to interact with the atoms of the diffraction grating in a classical electrostatic manner. Some other biomolecules might be more suitable- phthalocyanine is similar in structure to heme and chlorophyll.
Yeah, but the fact that scientists in Vienna scored their molecule movie with "The Third Man Theme" makes it totally worth it.
The upper bound on the age of this particular star is 15.4 billion years, so there you go. OK, I understand that it's a matter of vastly different types of measurements , models, and uncertainties, but I think it's funny that the age of the entire universe has been determined to within 110 million years but we only know the age of this particular star to +/-2.6 billion years, a range that encompasses the current age of the Sun.
Lifetime=1/Mass^2.5.
Note that lifetime here is as a ratio of solar lifetime (so a Lifetime of 1=10 billion years) and mass is in solar masses. The paper gives the mass of HIP 11952 as about 0.83 solar masses, so an estimated main sequence lifetime would be 1/0.83^2.5= 15.9 billion years, after which it would become a red giant. Not liking the odds for its planets at that time, especially the one with a 7 day orbital period. So, it probably has a long while left, though there are wide bounds listed for mass and age, so if it is actually older and heavier, it might be living on borrowed time.
That isn't the mechanism the paper is proposing. What the authors suggest is that trees uptake radon dissolved in groundwater, transpire it into the air, and that it is the radioactive decay of radon that would be responsible for the ions released by trees.
I was actually hoping that all the comments for this story were going to be about this.
It's a non-Euclidean triangle! To even imagine the Lovecraftian horrors that lie within would drive you mad!
Crossing over is normally a beneficial practice for chromosomes, and is a key advantage for sexual reproduction. See Muller's ratchet for the case of deleterious effects piling up in organisms who do not use recombination to shuffle around their genes. Therefore, it generally makes sense for chromosomes to pair up, so that at each generation, offspring get a mix of ancestral genes rather than a perfect (aside from mutation, of course) clone of a chromosome from parent's set. Being able to swap homologous genes dramatically increases the diversity of offspring. The X and Y pair is an exception because it would be a problem for recombination to occur. The genes on Y are supposed to be unique to males- if some regions of Y containing them recombined with X, those male-development specific genes could be traded away in exchange for nothing, likely leading to sterile offspring. Therefore, it has been to the advantage of XY-determination organisms to have X and Y as different as possible so that there is basically no recombination. The drawback is that Y doesn't get to recombine with anything (X can still crossover with another X), so a son's Y is essentially his father's Y and grandfather's Y, though with whatever errors have accumulated. This has led to a pruning of genes on Y over time- it appears from this paper that this deletion will not necessarily go to nothing, and that a "minimal Y" may be stable for many millions of years. It does however underline that the X/Y pair is a special case, that the endpoint of the asymmetric relationship that they have is for one chromosome to dwindle to a single purpose. The Y chromosome has 19 genes: X has around 2000.
It would appear, however, that Y chromosomes are a bit more robust than originally thought, and may be able to continue at their present level of basic function for tens of millions of years more. Just as my own thought, one reason for this may be the presence of genes on the Y which are necessary for sperm production. A transition to another form of sex determination would require those genes to be either moved or their functionality replaced elsewhere; otherwise any Y-less males would be azoospermic and therefore the new system wouldn't get passed on.
Well, there's no specific reason to favor the XY system of sex determination over some alternative arrangement, like the ZW system in birds (females are ZW, males are ZZ). In that case, the Z chromosome is larger and has more genes than the W. On the other hand, there's really no evidence to suggest that the XY system is any worse than the alternatives, or at least worse enough to support some sort of changeover (or lead to the extinction of placental and marsupial mammals). It does make sense to let Y "rot" to a certain extent: letting Y "cross over" with X is hazardous. It leads to the possibility of producing gametes that contain X chromosomes with male-sex determining genes, and gametes that contain Y chromosomes that lack those male-determining genes. It is to the system's benefit that X and Y are completely non-homologous, even factoring in the problem of X-linked diseases. It's theoretically possible that the function of Y could be captured in a single gene. However, chromosomes are also physical structures that have to be able to be manipulated by the machinery of the cell. It's likely that there is a minimum size for that to be done without high risk of error, which means that Y is safe.... for now.
For all but the most finicky of physics experiments, if we had pressure conditions of the density of the sun's corona, it would be "high vacuum." Very little conduction of heat from the plasma to a comet is going to take place. The bombardment by solar photons and the gigantic magnetic and gravitational fields of the sun play a greater role here than the actual material of the sun, and thus NASA can be pleasantly surprised by Comet Lovejoy's survival of its close encounter. But it's the wrong idea to picture this comet plunging into some sort of molten inferno. Of course, the sun's core is another story. 15 times denser than lead and 16 million kelvin. I'll like to see the comet that survives that.
The look of concentration on the piano player's face was great- carefully reading the music and playing the notes, when the end result sounds like it does when I sit down at a piano. I'll agree that it wasn't the worst piece of music I've ever heard. It certainly has its moments of cacophony wherever droning low notes are randomly following by a high plinking note, but I think the very fact that it is a collection of notes makes it sound like atonal music rather than true noise. Despite the lack of pattern, an expert player playing it on a tuned grand piano does a lot for the sound. Perhaps try the same composition, but instead of a piano, have someone scratching a chalkboard.
It wouldn't be so much tearing a hole in the fabric of space as making a ripple. The laser's electric field would make a wake in the sea of transient vacuum particles that prevents their instantaneous annihilation, and hopefully lets some exotic particles exist for long enough to be detected. Despite the idea that this "quantum foam" of seething virtual particles would be the fabric of space-time, the answers to where and when phenomena would be detected are most likely "in detectors just outside the laser's path" and "femtoseconds after the laser is fired" and not perhaps "in another universe" or "85 million years in the past." This is not a FOX show, after all.
Actually, far more energetic phenomena-- gamma ray bursts-- have been studied to observe the effects their travels through the fabric of space-time on the way to Earth have had, and the results have been pretty mundane. Even for ridiculously high-energy gamma ray photons, the fabric of the universe behaves as being essentially smooth and respectful of general relativity. Maybe we'll see something a bit wilder given a chance to take a closer look, but to describe "pushing some particles apart so we can see them" as "tear apart the vacuum of space" is a bit of an exaggeration.
The issue with that example is that there wasn't continuity of currency throughout that whole period. The infamous "papiermark" of 1923 was converted into the rentenmark of 1924 -at an exchange rate of a trillion to one, and then into the Reichsmark. After WWII, the Reichsmark was exchanged for the Deutsche Mark (in W. Germany at least) and that was your stable currency. The DM can even today be exchanged for euros, though I'd imagine most DM are out of circulation. The point is that other than the DM/ euro changeover, the transitions have been limited time arrangements, in one case backed with a military occupation. What came out of each was basically a new currency. You can turn in that shoebox of DM from 1994 and get crisp new euros at a rate of about 0.5 euro for each, but you can't exchange a quadrillion 1923 papiermarks for 500 trillion euro. Different money.
She looks like the real thing
She tastes like the real thing
My fake plastic love....
Stronger magnets are always going to be advantageous for a particle accelerator, so yeah, room temperature superconductors (ones that have all the necessary properties to make good electromagnets) would be a major breakthrough. However, in terms of making an accelerator like the Tevatron or the LHC smaller, there are some physical economies of scale that make see-it-from-space rings more suitable than lab scale. Circular accelerators lose energy due to synchrotron radiation; these losses are inversely proportional to the ring radius, so all things otherwise equal, bigger is better. Linear accelerators don't have this disadvantage, but they do require a series of electric field "drivers" along their lengths that pose major difficulties for miniaturization. Like the ring accelerators, the trend is to go big- the proposed International Linear Collider would be about 40km long. Smaller accelerators are of course useful for a number of scientific and even medical purposes, and there are a lot of experiments that compete for beam time at the big facilities- it'd be nice to have more available. However, a giant facility has capabilities that can't be matched by 1000 facilities with each 1/1000th the energy.
Oops- everyone who pointed out that that's the west coast of Central America is probably right- I was just going off another post that listed the cities. Even knowing what's being passed over, the angles of this video (which is spectacular) disorient me and I have trouble making heads or tails of it.
Oh, completely agree- it might be an arbitrary line, but it is a useful one.