In a ‘long shot’ theory, physicists propose that the world’s largest atom smasher could be used as a time machine to send a special kind of matter backward in time. The scientists outline a way to use the Large Hadron Collider (LHC), a 17-mile long (27-km) particle accelerator buried underground near Geneva, to send a hypothetical particle called the Higgs singlet to the past. There are a lot of “ifs” to the conjecture, including the major question of whether or not the Higgs singlet even exists and could be created in the machine. “Our theory is a long shot, but it doesn’t violate any laws of physics or experimental constraints,” physicist Tom Weiler of Vanderbilt University said in a statement. However, if the theory proves correct, the researchers say the method could be used to send messages to the past or the future. Weiler and Vanderbilt graduate fellow Chui Man Ho describe their idea in a paper posted March 7 on the research website arXiv.org. Elusive Higgs The Higgs singlet is related to another theorized but not yet detected particle called the Higgs boson . This particle, and its related Higgs field, are thought to confer mass on all the other particles, and its discovery could help scientists answer the question, why do some particles have more mass than others? The search for the Higgs boson was one of the main motivations for building the LHC in the first place. Since the atom smasher began regular operation last year, it has yet to find evidence of the Higgs boson, but the machine is still ramping up to its peak energies. If the collider does succeed in producing a Higgs boson , some theories predict that it will create a Higgs singlet at the same time. This particle may have a unique ability to jump out of the normal three dimensions of space and one dimension of time that we inhabit, and into a hidden dimension theorized to exist by some advanced physics models. By traveling through the hidden dimension, Higgs singlets could reenter our dimensions at a point forward or backward in time from when they exited. “One of the attractive things about this approach to time travel is that it avoids all the big paradoxes,” Weiler said. “Because time travel is limited to these special particles, it is not possible for a man to travel back in time and murder one of his parents before he himself is born, for example. However, if scientists could control the production of Higgs singlets, they might be able to send messages to the past or future.” M theory The test of the researchers’ theory will be whether the LHC shows evidence of Higgs singlet particles and their decay products spontaneously appearing. If it does, Weiler and Ho believe that they will have been produced by particles that travel back in time to appear before the collisions that produced them. The theory is based on M-theory, a ” theory of everything ” that attempts to unite the forces of nature and describe everything in the universe. It’s based on string theory, which posits that all particles are fundamentally made up of tiny vibrating strings. Theoretical physicists have developed M-theory to the point that it can accommodate the properties of all the known subatomic particles and forces, including gravity, but it requires 10 or 11 dimensions instead of our familiar four. This has led to the suggestion that our universe may be like a four-dimensional membrane or “brane” floating in a multi-dimensional space-time called the “bulk.” According to this view, the basic building blocks of our universe are permanently stuck to the brane and cannot travel in other dimensions. There are some exceptions, however. Some argue that gravity, for example, is weaker than other fundamental forces because it diffuses into other dimensions. Another possible exception is the proposed Higgs singlet, which responds to gravity but not to any of the other basic forces. 8 Shocking Things We Learned From Stephen Hawking’s Book Twisted Physics: 7 Mind-Blowing Findings Theory of Everything: Holy Grail or Fruitless Pursuit? Follow Yahoo! News on Twitter , become a fan on Facebook

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By Julie Steenhuysen CHICAGO | Fri Mar 4, 2011 3:28pm EST CHICAGO (Reuters) – U.S. researchers have coaxed stem cells into becoming a type of brain cell that dies off early in people with Alzheimer’s disease. The new technology would provide a ready supply of cells for use in testing new drugs or even transplants to help restore lost memory, the team reported on Friday in the journal Stem Cell. While most Alzheimer’s research is done in genetically modified mice, the new technique would allow researchers to study a key aspect of the disease in human cells. “These are cells that are critically important for memory functions,” said Dr. Jack Kessler of Northwestern University Feinberg School of Medicine in Chicago, who worked on the study. Kessler said the team used embryonic stem cells to create the neurons, which are thought to be among the earliest brain cells lost in Alzheimer’s disease. Stem cells are the body’s master cells, the source of all other cells. Embryonic stem cells, taken from days-old human embryos, are especially pliable. The technique to convert stem cells into neurons was developed by Christopher Bissonnette, a former doctoral student in Kessler’s lab, who was inspired by the death of his own grandfather from Alzheimer’s disease, a fatal brain-wasting form of dementia that affects memory, thinking and behavior. When Kessler and Bissonnette implanted the newly grown nerve cells into the brains of mice, they functioned normally, producing nerve fibers called axons and making the brain chemical acetylcholine, used to retrieve memories from other parts of the brain. The researchers say the technique can produce an almost infinite number of these cells, giving other scientists the chance to study these cells. ORDINARY SKIN CELLS The team has used the same approach to make induced pluripotent stem cells, in which ordinary skin cells are reprogrammed into an embryonic-like state. Using these cells, also known as iPS cells, the researchers converted them into brain cells or neurons. The advantage of iPS cells, Kessler said, is they can be made from people with known Alzheimer’s disease, allowing researchers to study differences between healthy cells and diseased cells. The team made neurons from Alzheimer’s patients, healthy people with no family history of Alzheimer’s, and people who are healthy but have a genetic predisposition to develop the disease. “These are real people with real disease. That’s why it’s exciting,” Kessler said. Kessler said the technology is far from ready, but that eventually it may be possible to make replacement memory cells that can be transplanted into people with Alzheimer’s. 1 2 Next

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Stocks     A woman walks past an artwork by Athina Robie depicting Aids awareness ribbons at an exhibition inside Athens’ Syntagma metro station marking World Aids Day December 1, 2005. Credit: Reuters/Yiorgos Karahalis LOS ANGELES | Mon Feb 28, 2011 9:31am EST LOS ANGELES (Reuters) – An experimental gel containing a prescription HIV drug has been shown for the first time to protect rectal tissue against the virus that causes AIDS, according to new research. The gel, containing Gilead Sciences Inc’s AIDS drug tenofovir, has previously been shown to sharply reduce HIV infections in women when applied inside the vagina. The latest study, which involved rectal tissue biopsies taken from HIV-negative men and women who used the product daily for one week, provides the first evidence that tenofovir gel could help reduce the risk of HIV from anal sex. The researchers, who presented the findings at a medical meeting in Boston, are reformulating the gel so that it is less harmful to the rectum than the original vaginal microbicide. The risk of becoming infected with HIV from unprotected anal sex may be at least 20 times greater than unprotected vaginal sex, in part because the rectal lining is only one-cell thick compared to the vagina’s multiple layers, making it easier for the virus to reach cells to infect, the researchers said in a statement. Tissue samples obtained in the study were sent to a laboratory where they were exposed to HIV. The study found that the virus was significantly blocked in samples from participants who used tenofovir gel compared with samples from participants who used a placebo gel. An oral dose of tenofovir was not shown to provide protection from HIV. Although the study found use of the gel generally safe, two participants had severe gastrointestinal side effects, including diarrhea and lower abdominal cramps. Another study is under way using a formulation of tenofovir gel with less glycerin, an additive found in many gel-like products, in the hope that this will make it better tolerated. A separate mid-stage study presented at the meeting compared the oral and gel forms of the drug in American and African women. It found that daily use of tenofovir gel resulted in a more than 100-times higher concentration of active drug in vaginal tissue compared with use of an oral tablet. Compared with the gel, a daily tablet was associated with a 20-times higher active drug concentration in blood. “How the differences between the gel and the tablet will translate in terms of protective effect, we can’t say just yet,” Dr. Craig Hendrix, a professor of medicine and pharmacology at Johns Hopkins School of Medicine in Baltimore and the study’s leader, said in a statement. Most American women studied in the trial favored the oral tablet. The African women favored the gel and tablet equally, although many of them said they liked the gel because it enhanced sexual pleasure, the researchers reported. (Reporting by Deena Beasley, editing by Matthew Lewis)

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