U.S. physicists said they have achieved a new understanding of high temperature superconductors that might overturn many existing theories.
Superconductors are able to transmit electricity with no resistance at temperatures well above absolute zero. Scientists have long understood that if superconductors could be made to work at room temperatures, they would have potentially limitless applications.
In the new study, Massachusetts Institute of Technology researchers looked at the state of that superconductors inhabit just above the temperature at which they start to superconduct -- a state called the pseudogap. It had already been shown that natural impurities in a superconducting material, such as a missing or replaced atom, allow electrons to reach energy levels normally within the superconducting gap, so they can scatter.
The new MIT study shows scattering by impurities occurs not only when a material is in the pseudogap state but also when it's in the superconducting state.
The finding challenges the theory that the pseudogap is only a precursor state to the superconductive state and offers evidence that the two states can coexist, the physicists said.
Thursday, February 14, 2008
Scientists remove bottleneck in genetic sequencing
Researchers at the Broad Institute of MIT and Harvard, USA, have successfully employed a new technique developed by Agilent that could potentially eliminate one of the biggest bottlenecks in the genetic sequencing process.
The researchers, who presented their work at the Advances in Genome and Biology Technology conference in Florida, USA last week, successfully identified previously unknown somatic mutations in tumours. It represents one of the first instances in which Agilent's inkjet-printing method of rapidly creating oligonucleotide probes has been successfully deployed in real scientific research.
When studying genetic variations, researchers frequently only need to study specific sections that are relevant to a particular disease, instead of studying the whole genome. "They can use custom oligonucleotide mixtures to isolate and enrich genomic segments they're interested in, rather than having to sequence the entire genome," Emily LeProust, Agilent's manager of chemistry development, told LabTechnologist.com
To do this, they need to create many copies of the sections that they want to study which can then act as probes for further research. All of the other steps in the sequencing process have seen improvements in new, "parallel" techniques that can study many different sequences simultaneously, but until now there has been no equivalent technique for creating artificially amplifying sections of the genome in this way. Current techniques, such as polymerase chain reactions, are length processes that create a bottleneck that holds up genomic projects.
Agilent's new technique, called Oligo Library Synthesis, could be the answer. It is quicker and less costly than other methods, with the capacity to create up to 55,000 customer-defined oligonucleotides in a single tube.
"To create a mixture of 55,000 oligos individually using PCR would take many months and cost millions of dollars. The OLS capability creates these mixtures very quickly and cost-effectively," explained LeProust. "We use a sophisticated inkjet type 'printer' to synthesise as many as 244,000 oligonucleotide probes on a one-inch by three-inch glass wafer."
Chad Nusbaum, co-director of the genome sequencing and analysis programme at the Broad Institute, believes it is a very effective technique: "We prepared a labelled derivative of Agilent's oligo libraries to use for direct capture of target sequences by hybridisation. The method is highly multiplexed, with a simple, efficient and inexpensive laboratory process, thus overcoming the sample preparation bottleneck."
The technique reportedly offers many other advantages in addition to its speed. According to LeProust, customers have reported that the oligonucleotides are of a better quality than traditional techniques. It can also create very long sections of DNA, up to 200 base pairs in length, which would not have been possible using previous methods.
Agilent is currently providing its Oligo Library Synthesis to a small set of research groups before it becomes a commercially available product or service.
The researchers, who presented their work at the Advances in Genome and Biology Technology conference in Florida, USA last week, successfully identified previously unknown somatic mutations in tumours. It represents one of the first instances in which Agilent's inkjet-printing method of rapidly creating oligonucleotide probes has been successfully deployed in real scientific research.
When studying genetic variations, researchers frequently only need to study specific sections that are relevant to a particular disease, instead of studying the whole genome. "They can use custom oligonucleotide mixtures to isolate and enrich genomic segments they're interested in, rather than having to sequence the entire genome," Emily LeProust, Agilent's manager of chemistry development, told LabTechnologist.com
To do this, they need to create many copies of the sections that they want to study which can then act as probes for further research. All of the other steps in the sequencing process have seen improvements in new, "parallel" techniques that can study many different sequences simultaneously, but until now there has been no equivalent technique for creating artificially amplifying sections of the genome in this way. Current techniques, such as polymerase chain reactions, are length processes that create a bottleneck that holds up genomic projects.
Agilent's new technique, called Oligo Library Synthesis, could be the answer. It is quicker and less costly than other methods, with the capacity to create up to 55,000 customer-defined oligonucleotides in a single tube.
"To create a mixture of 55,000 oligos individually using PCR would take many months and cost millions of dollars. The OLS capability creates these mixtures very quickly and cost-effectively," explained LeProust. "We use a sophisticated inkjet type 'printer' to synthesise as many as 244,000 oligonucleotide probes on a one-inch by three-inch glass wafer."
Chad Nusbaum, co-director of the genome sequencing and analysis programme at the Broad Institute, believes it is a very effective technique: "We prepared a labelled derivative of Agilent's oligo libraries to use for direct capture of target sequences by hybridisation. The method is highly multiplexed, with a simple, efficient and inexpensive laboratory process, thus overcoming the sample preparation bottleneck."
The technique reportedly offers many other advantages in addition to its speed. According to LeProust, customers have reported that the oligonucleotides are of a better quality than traditional techniques. It can also create very long sections of DNA, up to 200 base pairs in length, which would not have been possible using previous methods.
Agilent is currently providing its Oligo Library Synthesis to a small set of research groups before it becomes a commercially available product or service.
MIT researchers use nanotechnology to personalize drug therapy
Nanoparticles and silicon chips could target cancerous tumors or individual organs
Researchers at MIT have developed a new nanotechnology that could someday be implanted in the human body to target tumors or specific organs with time-released drug dosages.
Layering charged nanoparticles with medications like chemotherapy drugs or insulin, scientists are hoping to directly deliver drugs for critical and chronic diseases such as cancer and diabetes, according to Paula Hammond, a Bayer professor of chemical engineering at MIT. Once the layered device is in the body, it will be activated by a remote control or a silicon chip programmed to dispense specific dosages at specific intervals.
"I think this actually marks a new direction for medicine, which is the personalization of medical care," said Hammond, who has been working on this project for the past four years. "There's an interest in being able to better design a procedure [specific] to the patient's individual needs, instead of using the same protocols for every patient -- especially in life-and-death areas like cancer or chronic disorders like diabetes. As we build more and more of these smart systems that can respond to some stimulus, we become more capable of designing these personalized approaches to therapy."
The layers of nanoparticles and medications form a thin film -- on the nanometer scale. "We are incorporating drugs into the film layer by layer. There's the medication layer and the nanocrystal layer," explained Hammond. "It's like building a sandwich with negative and positive materials on top of each other. When we apply a small electrical field, just a little jolt, a little bit of that film falls apart. When that happens, this sandwich, which is held together by positive and negative charges, begins to fall apart."
And as a layer of the film disintegrates, the medication is released. The amount of drug delivered and the timing of the dosage can be precisely controlled by turning the voltage on and off.
The electrical field can be created by a remote control or by a silicon chip and microbattery, added Hammond.
The patient would not swallow this film. It would be implanted inside the body. For instance, if the patient is fighting a cancerous tumor, the film could be implanted on the tumor itself. And if a tumor is removed from a patient but doctors worry that the cancer could return, they could deposit the film in the area where the tumor had been.
The MIT team is working on loading the films with different cancer drugs.
"We're looking at the potential of incorporating chemotherapy drugs and using an insert placed in or near a tumor so the chemo drugs can be released in pulses over a long period of time," said Hammond. "You would have absolute control over it. If you needed to, you could apply more medication or you could stop the medication."
She added that at some point, a computer chip might be able to recognize a patient's rising blood-sugar levels and trigger the film to release insulin to the pancreas, or the chip could sense that an epileptic patient is about to have a seizure and trigger the film to release needed medication to stop it.
Hammond said researchers just finished developing the materials, including the nanoparticles and the film. The next step will be to work on releasing the drugs to cell cultures. They could begin testing on mice as early as a year from now, with large-animal and human testing slated for four to five years from now, according to the professor.
Researchers at MIT have developed a new nanotechnology that could someday be implanted in the human body to target tumors or specific organs with time-released drug dosages.
Layering charged nanoparticles with medications like chemotherapy drugs or insulin, scientists are hoping to directly deliver drugs for critical and chronic diseases such as cancer and diabetes, according to Paula Hammond, a Bayer professor of chemical engineering at MIT. Once the layered device is in the body, it will be activated by a remote control or a silicon chip programmed to dispense specific dosages at specific intervals.
"I think this actually marks a new direction for medicine, which is the personalization of medical care," said Hammond, who has been working on this project for the past four years. "There's an interest in being able to better design a procedure [specific] to the patient's individual needs, instead of using the same protocols for every patient -- especially in life-and-death areas like cancer or chronic disorders like diabetes. As we build more and more of these smart systems that can respond to some stimulus, we become more capable of designing these personalized approaches to therapy."
The layers of nanoparticles and medications form a thin film -- on the nanometer scale. "We are incorporating drugs into the film layer by layer. There's the medication layer and the nanocrystal layer," explained Hammond. "It's like building a sandwich with negative and positive materials on top of each other. When we apply a small electrical field, just a little jolt, a little bit of that film falls apart. When that happens, this sandwich, which is held together by positive and negative charges, begins to fall apart."
And as a layer of the film disintegrates, the medication is released. The amount of drug delivered and the timing of the dosage can be precisely controlled by turning the voltage on and off.
The electrical field can be created by a remote control or by a silicon chip and microbattery, added Hammond.
The patient would not swallow this film. It would be implanted inside the body. For instance, if the patient is fighting a cancerous tumor, the film could be implanted on the tumor itself. And if a tumor is removed from a patient but doctors worry that the cancer could return, they could deposit the film in the area where the tumor had been.
The MIT team is working on loading the films with different cancer drugs.
"We're looking at the potential of incorporating chemotherapy drugs and using an insert placed in or near a tumor so the chemo drugs can be released in pulses over a long period of time," said Hammond. "You would have absolute control over it. If you needed to, you could apply more medication or you could stop the medication."
She added that at some point, a computer chip might be able to recognize a patient's rising blood-sugar levels and trigger the film to release insulin to the pancreas, or the chip could sense that an epileptic patient is about to have a seizure and trigger the film to release needed medication to stop it.
Hammond said researchers just finished developing the materials, including the nanoparticles and the film. The next step will be to work on releasing the drugs to cell cultures. They could begin testing on mice as early as a year from now, with large-animal and human testing slated for four to five years from now, according to the professor.
Ambitious NYU must look to Harvard, MIT
What will it mean to be a top-tier university 20 years from now? Some in NYU's administration are staking the future of our university on the hope they know the answer. They dream of global networks and seek the funds to make their international mirages materialize. They reimagine cities with the same gusto that they redefine the research university's role in them. They expand across rivers and oceans with divining rod in one hand, cap in the other. There is ambition and hope and no promise of success.
The goal seems clear enough: vaulting NYU into the ranks of America's elite universities. But in their rush, we wonder whether some in our administration are overlooking the changes that will genuinely revolutionize universities by spreading information on a truly global scale. Frankly, its old news: Technology, and how universities choose to use it, will be the anvil on which new reputations will be forged. The universities that embrace it will lead their peers into the 21st century - they will be, if they are not already, among our nation's finest. This includes podcasting, open courseware and the digitization of library holdings. It also includes open access.
Never heard of it? We didn't either until word came in that yesterday, Harvard University's Faculty of Arts and Science voted in favor of an Open Access policy, the first in the nation. This plan allows for FAS's faculty to post their articles and research online, bypassing exclusive deals with scholarly journals while offering content to everyone with internet access. For free. This will distribute scientific and scholarly research to many while leveling costs on a select few - primarily, the university itself.
How will it work? Every article written by any FAS faculty member will automatically be deposited in an open-access repository maintained by the university's library, unless the professor specifically asks to opt out of the database. The authors will still be able to publish their articles in the journal of their choice; they would continue to maintain copyright over their work. Instead of searching through costly journals, a growing body of research will be located in one (hopefully) easy-to-use spot. Everyone stands to benefit: students, professors, universities and the many who seek study for its own sake. The success of MIT's open courseware - just look up professor Walter H.G. Lewin - proves that they exist, while giving new life to NYU's old motto: "A private university in the public service."
If we want to know what it will take to become a top-tier research university, we don't have to look far. Let's just hope it's not old news before NYU catches on
The goal seems clear enough: vaulting NYU into the ranks of America's elite universities. But in their rush, we wonder whether some in our administration are overlooking the changes that will genuinely revolutionize universities by spreading information on a truly global scale. Frankly, its old news: Technology, and how universities choose to use it, will be the anvil on which new reputations will be forged. The universities that embrace it will lead their peers into the 21st century - they will be, if they are not already, among our nation's finest. This includes podcasting, open courseware and the digitization of library holdings. It also includes open access.
Never heard of it? We didn't either until word came in that yesterday, Harvard University's Faculty of Arts and Science voted in favor of an Open Access policy, the first in the nation. This plan allows for FAS's faculty to post their articles and research online, bypassing exclusive deals with scholarly journals while offering content to everyone with internet access. For free. This will distribute scientific and scholarly research to many while leveling costs on a select few - primarily, the university itself.
How will it work? Every article written by any FAS faculty member will automatically be deposited in an open-access repository maintained by the university's library, unless the professor specifically asks to opt out of the database. The authors will still be able to publish their articles in the journal of their choice; they would continue to maintain copyright over their work. Instead of searching through costly journals, a growing body of research will be located in one (hopefully) easy-to-use spot. Everyone stands to benefit: students, professors, universities and the many who seek study for its own sake. The success of MIT's open courseware - just look up professor Walter H.G. Lewin - proves that they exist, while giving new life to NYU's old motto: "A private university in the public service."
If we want to know what it will take to become a top-tier research university, we don't have to look far. Let's just hope it's not old news before NYU catches on
Scientists unearth most primitive bat ever found
Bats flew before they had 'radar,' fossil shows
A fossil found in Wyoming has apparently resolved a long-standing question about when bats gained their radarlike ability to navigate and locate airborne insects at night.
The answer: after they started flying.
The discovery revealed the most primitive bat known, from a previously unrecognized species that lived about 52 million years ago.
Its skeleton shows that it could fly but lacked a series of bony features associated with echolocation, the use of high-pitched sounds to locate objects and prey in the surrounding environment, researchers said.
Until now, all the early known fossil bats showed evidence of both flying and echolocating, so it couldn't be determined which ability came first, said researcher Nancy Simmons.
Her team's research appears in today's issue of the journal Nature. Simmons chairs the vertebrate zoology division at the American Museum of Natural History in New York.
The early bat's wingspan was nearly a foot, just a bit less than that of today's big brown bat, she said.
Its teeth show that it ate insects, which it evidently plucked off surfaces after seeing, smelling or hearing them, she said.
Simmons said she suspects that the bat was active at night but that there's no evidence of that.
The creature was unusual in having a claw on all five fingers rather than just one or two.
MORE..
The most primitive bat ever found fluttered around about 52 million years ago, but lacked a key feature seen in most bats -- the ability to echolocate, hunting and navigating using a kind of sonar.
A team of scientists announced the discovery on Wednesday of a medium-sized ancient bat called Onychonycteris finneyi that possessed fully developed wings and was completely capable of flying. But they said that based on the evidence from its skeleton it lacked the ability to echolocate.
Kevin Seymour of the Royal Ontario Museum in Canada, one of the scientists who describe it in the journal Nature, said this bat appears to settle a long-standing debate of which came first in bats -- echolocation or flight. The answer is flight.
"It is like this is sort of half way to being a modern bat. It's the most primitive bat that we know. It could clearly fly. But it could not echolocate. The evidence from the skull and throat region shows us none of the features that echolocating bats have," Seymour said in a telephone interview.
Bats are the second most common type of mammal living today, constituting a fifth of all mammal species. Only rodents, which make up half of mammals, are more plentiful.
Bats also are an ancient form of mammals, and scientists have struggled to understand their early evolutionary history. Onychonycteris, unearthed in 2003 in southwestern Wyoming, appears to be filling in some important gaps.
"MISSING LINK"
"It's clearly a bat, but unlike any previously known," Nancy Simmons of the American Museum of Natural History in New York said in a statement. "In many respects it is a missing link between bats and their nonflying ancestors."
Echolocation is a form of sonar used by several mammals to navigate and hunt. They use high-pitched sounds to find the location of objects by the sounds reflected from them. Most bats use it to find flying insects to catch in mid-air. Other mammals with this ability include whales, dolphins and shrews.
The scientists called the fossil of Onychonycteris beautifully preserved, representing a previously unknown bat family. But while they call it the most primitive bat, they said a bat with more modern features, Icaronycteris, lived at the same time. Icaronycteris used echolocation, they said.
Seymour said there is nothing unusual about more primitive forms living alongside more advanced ones. "That's completely normal. Think today of the monotremes living in Australia, the egg-laying mammals," Seymour said. These include the platypus.
The wingspan of Onychonycteris was about 12 inches. It had short, broad wings, suggesting it probably could not fly as quickly as most bats that appeared later. Rather than flapping its wings continuously while flying, it may have alternated flapping and gliding while in the air.
Its teeth suggest its diet consisted mostly of insects, like most bats today. It had claws on all five of its fingers, while modern bats have them on only one or two digits of each hand. Its limb proportions are different from all other bats.
Seymour said scientists are not certain from what type of mammal bats evolved, but it could have been a tree-dwelling insectivore like a shrew.
Bats are one of only three types of vertebrates in the history of Earth to develop the ability to fly, joining the flying reptiles called pterosaurs, which went extinct 65 million years ago, and birds.
Astronauts Continue Work On Columbus Lab
Astronauts Work on Columbus Lab
With two of their three spacewalks completed, the astronauts aboard the linked shuttle-station complex focused Thursday on getting the new Columbus lab up and running.
NASA extended Atlantis' mission by a day on Wednesday to give the crew more time to work on the lab, Europe's main contribution to the international space station.
The activation process has been running a little behind because of computer problems, but flight directors believe they've fixed the glitch.
The crew woke up Thursday to "Consider Yourself" from the musical "Oliver!" Astronaut Stanley Love thanked his wife, children and extended family, who he joked "may be feeling there's one fewer Love on Earth this Valentine's Day."
"I'd like to assure them that it's great to be up here, and I'll be home soon," he said.
Love was one of two spacewalkers who helped install Columbus on Monday. He is scheduled to participate in the mission's third outing on Friday to attach a pair of science experiments to the outside of the European module.
In addition to spending time Thursday preparing for that spacewalk — and enjoying some much-needed off-duty time — the crew plans to chat with German Chancellor Angela Merkel.
Her countryman, astronaut Hans Schlegel, completed his first spacewalk on Wednesday after an illness forced mission managers to pull him from Monday's outing.
Looking and sounding fit, Schlegel and Rex Walheim completed their primary job halfway through the nearly seven-hour spacewalk: removing a depleted nitrogen tank from the space station and installing a full one weighing 550 pounds. The high-pressure nitrogen gas is needed to flush ammonia through the station's cooling lines.
Neither Schlegel nor anyone else at the European Space Agency or NASA will say what was wrong with him. Schlegel, 56, has said it's a private medical matter.
Atlantis will remain at the space station until Monday. That makes for a 13-day flight, with touchdown now set for Feb. 20. The shuttle's thermal shielding has been completely cleared for re-entry.
more.....
Zero gravity can be heavy burden
The astronauts aboard space shuttle Atlantis gleefully float tools and a miniature football in midair. They look like they're having fun.
They're also coping with the million-and-one annoyances of the weightless lifestyle. The truth about zero-g, as the astronauts call it, is that it's a major pain.
In weightlessness, "two things are easier" — carrying heavy items and fitting into small spaces — and "everything else is more difficult," says astronaut Scott Kelly, who last flew on the shuttle in 2007.
The problems posed by zero gravity can make it harder for the crew, especially rookies, to get things done. That's no small matter now that shuttle missions are jammed with so much work that the astronauts have little time for sleep and meals.
Wednesday, Atlantis astronauts Rex Walheim and Hans Schlegel contended with tools that wanted to drift away as the men made a six-hour, 45-minute spacewalk to upgrade the cooling system on the International Space Station.
It was the first spacewalk for Schlegel, who sat out an assigned spacewalk Monday because of an undisclosed illness. Astronaut Stanley Love took his place.
"You guys did an outstanding job today," spacewalk coordinator Alan Poindexter said from inside the shuttle as the spacewalk ended.
Zero gravity can complicate exotic activities such as a spacewalk, but doing even mundane chores "is a challenge," Atlantis commander Stephen Frick said before the flight. "It's really something we have to work with a lot."
During Frick's first flight, crewmate Walheim kept finding things Frick had lost, "so it's a good thing that I'm flying with Rex again, so he can fulfill that task," Frick joked.
Eating in zero gravity is so inconvenient — food easily drifts out of containers and splatters — that astronauts in orbit often skimp on food. Astronaut Charlie Hobaugh said after his 13-day shuttle flight in 2007 that's one reason he lost 8 pounds in orbit.
Other tasks that are easy on Earth and tricky in space:
•Tying your shoes. The astronauts on the International Space Station wear sneakers during their runs on the station's treadmill. At first, putting them on without floating away is a puzzle.
"You have to figure out how to hold yourself down while you use both hands and one foot to tie that shoe," astronaut Clay Anderson said after spending five months on the station in 2007.
•Moving from one place to another. Novices tend to shove off walls to get somewhere, then grab something to stop themselves. Often their bodies stop, but their feet keep going.
"I felt like the first two days in space, all I kept saying was, 'Oh, I'm sorry, I didn't mean to kick you in the head,' " said astronaut Heidemarie Stefanyshyn-Piper after her first shuttle mission in 2006.
•Handling electrical cables or other items that tend to coil. On Earth, if you run a power cord between an outlet and a piece of equipment, it lies flat.
In orbit, the cord "will float up and assume whatever coil shape it was in before and take up a whole bunch of (space) that you wanted to get into," astronaut Michael Lopez-Alegria said after his 2006-2007 stint on the station.
•Using the bathroom. Astronauts don't go into detail, but they make it clear that the hoses and vacuums on space toilets leave something to be desired.
"You never really appreciate gravity till you think about going to the bathroom without it," station crewmember Dan Tani said in December. "Trust me, there are times when I really could use some gravity." He'll get it soon: he'll return to Earth on Atlantis, which is scheduled to return next Wednesday.
Astronauts train exhaustively, often for years, for their missions in space, but NASA can't train them to live in zero gravity. The best it can do is send rookies up in a jet that flies a series of upside-down-U-shaped curves. At the peak, passengers experience 25 to 30 seconds of weightlessness.
After that experience, "you think you know it all," Schlegel said before his flight. "Then you come into space and you realize, wow, (weightlessness) doesn't go away. It stays. … To some people, (adjusting) comes easy; to some people, it comes with more difficulties."
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