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Erich Feldmeier

Mendeley Research Blog - 0 views

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    "Academics have to publish in high-Impact Factor journals to receive promotions, tenure, or grant funding, and universities allocate their million-dollar library budgets to those same high-Impact Factor journals. This is despite the Impact Factor's many known flaws - the most limiting of which is that the citations it is based on take 3-5 years to accumulate"
Skeptical Debunker

Controversial Studies Trigger Dropoff in Osteoporosis Treatment - 0 views

  • The North American Spine Society and the Society of Interventional Radiology have pointed to flaws in both studies. And earlier studies, published over 15 years, found major benefits to kyphoplasty and a related procedure called vertebroplasty. "We're missing opportunities for patients to receive a safe and effective treatment that can significantly reduce their pain and disability," said Malamis, an interventional radiologist. The procedures are used to treat vertebral compression fractures in patients with osteoporosis and other conditions that result in brittle bones. In a vertebroplasty, an acrylic cement is injected into a fractured vertebra. In a kyphoplasty, a balloon-tipped catheter first is inserted into the fracture. The balloon is inflated to restore the height and shape of the vertebra before the cement is injected. Neva Nelson, 74, of Naperville, Ill., said a kyphoplasty that Malamis performed in October, 2009, has greatly reduced her pain in a vertebra in her lower back that she fractured after falling on ice. Before her kyphoplasty, Nelson had to sit on cushions. Walking, and especially standing, were painful. "I had to do something," she said. "I could not go on like that." Nelson said that since undergoing her kyphoplasty, "I don't have to worry about my back any more." In the controversial studies, patients were randomly assigned to receive a vertebroplasty or a placebo-like "sham" procedure. In the sham procedure, patients received an injection of anesthetic, but no cement. However, patients in severe pain are reluctant to enroll in a trial where there's a 50 percent chance of receiving a sham treatment. In one of the studies, researchers had to screen 1,813 patients to enroll just 131 subjects. In the other study, only 78 of 219 eligible patients were enrolled. This low enrollment rate raises the possibility that the patients who did enroll were not representative. Patients experience the greatest pain during the first three months after a compression fracture. Thereafter, pain gradually subsides. Thus, a vertebroplasty or kyphoplasty provides the greatest benefit when performed within a week or two of the fracture. But the studies enrolled patients up to 12 months after fractures. In addition to reducing pain and disability, a kyphoplasty can reduce the risk of subsequent fractures by improving the angle and height of the spine. The studies evaluated vertebroplasty alone, and did not include the more innovative and very different kyphoplasty procedure. Malamis suggests the medical community wait for the results of additional studies now underway before passing final judgment on vertebroplasty or kyphoplasty. In the mean time, he notes that Medicare still covers the procedures.
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    Dr. Angelo Malamis says that 90 percent of his patients who have undergone a treatment called balloon kyphoplasty for vertebral fractures report significant reductions in pain and disability. But the number of kyphoplasty referrals Malamis has received from primary care doctors has dropped sharply since two controversial studies were published last year in the New England Journal of Medicine. In findings that have been disputed by two medical societies, researchers reported that a procedure related to kyphoplasty was not significantly better than a placebo-like procedure in reducing pain and disability.
Mike Chelen

RNA world easier to make : Nature News - 0 views

  • John Sutherland and his colleagues from the University of Manchester, UK
  • ribonucleotide
  • building block of RNA
  • ...29 more annotations...
  • Donna Blackmond, a chemist at Imperial College London.
  • strong evidence for the RNA world
  • 'RNA world' hypothesis, which suggests that life began when RNA, a polymer related to DNA that can duplicate itself and catalyse reactions
  • chemists had thought the subunits would probably assemble themselves first, then join to form a ribonucleotide
  • three distinct parts: a ribose sugar, a phosphate group and a base
  • RNA polymer is a string of ribonucleotides
  • efforts to connect ribose and base together have met with frustrating failure
  • researchers have now managed to synthesise
  • ribonucleotides
  • remedy is to avoid producing separate ribose-sugar and base subunits
  • makes a molecule whose scaffolding contains a bond that will
  • be the key ribose-base connection
  • atoms are then added around this skeleton
  • final connection is to add a phosphate group
  • influences the entire synthesis
  • acting as a catalyst, it guides small organic molecules into making the right connections
  • What we have ended up with is molecular choreography
  • objectors to the RNA-world theory say the RNA molecule as a whole is too complex to be created using early-Earth geochemistry
  • flaw is in the logic — that this experimental control by researchers in a modern laboratory could have been available on the early Earth
  • Robert Shapiro, a chemist at New York University
  • early-Earth scenarios
  • heating molecules in water, evaporating them and irradiating them with ultraviolet light
  • results showing that they can string nucleotides together
  • ultimate goal is to get a living system (RNA) emerging from a one-pot experiment
  • need to know what the constraints on the conditions are first
  • Shapiro sides with
  • another theory of life's origins
  • because RNA is too complex to emerge from small molecules, simpler metabolic processes
  • eventually catalysed the formation of RNA and DNA
Skeptical Debunker

Scientists find an equation for materials innovation - 0 views

  • By reworking a theory first proposed by physicists in the 1920s, the researchers discovered a new way to predict important characteristics of a new material before it's been created. The new formula allows computers to model the properties of a material up to 100,000 times faster than previously possible and vastly expands the range of properties scientists can study. "The equation scientists were using before was inefficient and consumed huge amounts of computing power, so we were limited to modeling only a few hundred atoms of a perfect material," said Emily Carter, the engineering professor who led the project. "But most materials aren't perfect," said Carter, the Arthur W. Marks '19 Professor of Mechanical and Aerospace Engineering and Applied and Computational Mathematics. "Important properties are actually determined by the flaws, but to understand those you need to look at thousands or tens of thousands of atoms so the defects are included. Using this new equation, we've been able to model up to a million atoms, so we get closer to the real properties of a substance." By offering a panoramic view of how substances behave in the real world, the theory gives scientists a tool for developing materials that can be used for designing new technologies. Car frames made from lighter, strong metal alloys, for instance, might make vehicles more energy efficient, and smaller, faster electronic devices might be produced using nanowires with diameters tens of thousands of times smaller than that of a human hair.
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    Princeton engineers have made a breakthrough in an 80-year-old quandary in quantum physics, paving the way for the development of new materials that could make electronic devices smaller and cars more energy efficient.
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