শনিবার, ৪ মে, ২০১৩

Muscle adaptation of transition to minimalist running

May 2, 2013 ? For tens of thousands of years, humans ran on bare feet. Then we developed an assortment of specialized shoes, including -- particularly since the 1960s -- a seemingly limitless variety of running shoes. Despite the perceived advantages of foot protection, some runners in recent years have returned to barefoot running, believing it is a more natural way to run and therefore less injurious to the feet and legs.

As a result, several shoe manufacturers have produced specialized "minimalist" shoes to accommodate this, such as the Vibram FiveFingers shoes. Such shoes allow a runner to imitate barefoot running while providing some sole and toe protection. The design allows the feet and toes to spread out and conform to the terrain with each step, rather than being boxed in and stabilized by a contoured and cushioned shoe design.

The difference results in a different running stride -- people in running shoes strike first with the heel (because of all the cushioning), whereas barefoot and minimalist runners strike first with the forefoot. This difference affects how the muscles of the legs and feet respond and develop.

But, exactly, how do the muscles change when adapting to a new running style?

That is the question researchers at the University of Virginia are asking in a new one-of-a-kind study of runners who are transitioning from shoed running style to minimalist running.

"We want to know what happens to the muscles of the leg and foot when recreational runners make the switch to minimalist footwear," said Geoffrey Handsfield, a U.Va. Ph.D. student in biomedical engineering who is leading the study. "Many minimalist shoe manufacturers make claims that their shoes will lead to strengthening the muscles of the calf and feet while avoiding common running injuries. However, there is little scientific evidence supporting these claims."

The researchers aim to find out exactly which muscles get bigger or weaken, which elongate or shorten, and if some muscles do not change.

Handsfield and his co-investigators, biomedical engineering professor Silvia Blemker (Handsfield's adviser) and third-year undergraduate biomedical engineering student Natalie Powers, are using static and dynamic MRI with motion capture cameras and an instrumented treadmill to track the running technique and muscle tissue adaptations of recreational runners transitioning to minimalist running technique.

"Most studies and discussions have been about running form and the effects on bones and joints, but we're taking a different approach," Handsfield said. "We think it's relevant to look at the muscles' adaptations, which also affect the bones and joints in their interactions."

He said this is among the first longitudinal studies of runners switching to a new running technique and using a minimalist shoe, and the first to use advanced imaging to study the effects on muscles of different running techniques.

"Dynamic MRI allows us to image the tissue very rapidly so that we can observe displacements of the muscle tissue as our subject performs a controlled cyclic exercise," Handsfield said. "We're also using static MRI to determine the subjects' muscle volumes and lengths before and after their transition to minimalist footwear, allowing us to quantify how their muscles changed with minimalist training."

The researchers are not attempting to prove one running style is better than the other; rather they are interested in the affects of the change on muscles. The eventual results could help runners make their own decisions regarding footwear and running styles.

"Shoe companies are generally not equipped to undergo fundamental studies aimed at understanding how shoe designs affect muscles," Blemker said. "At a university, we are able to focus on this type of research that ultimately both advances our fundamental understanding of muscle adaptation and potentially provides a scientific basis for future shoe designs."

The researchers have completed the first phase of their study -- mapping the muscles of study participants who run in standard running footwear. They are about to begin the second phase, which will map changes to the muscles as those runners transition to minimalist footwear. The runners are 23- to 30-year-old recreational runners who run 12 to 30 miles per week.

The research is funded by a U.Va. "Double 'Hoo" grant that pairs graduate and undergraduate students (Handsfield and Powers) on research projects, and by a gift from the Merrell shoe company, which manufactures minimalist footwear.

The technology used in the study was developed under a project funded by the U.Va.-Coulter Translational Research Partnership. The same technology has also been applied to studying muscles in children with cerebral palsy, adults with knee pain and elite and collegiate athletes.

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Story Source:

The above story is reprinted from materials provided by University of Virginia, via Newswise.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/most_popular/~3/0sZXrqAyHj8/130502142443.htm

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Book Review : BOOK REVIEW: Gulp: Adventures on the Alimentary Canal by Mary Roach

Review by Erika Engelhaupt

By Mary Roach

Web edition: May 3, 2013
Print edition: May 18, 2013; Vol.183 #10 (p. 30)

It?s no coincidence that the word ?visceral? refers both to entrails and to the sensation one feels on a roller coaster. We humans have a love-hate relationship with our guts, and Roach?s latest book capitalizes on that mix of fascination and repulsion to lure us into reading about the digestive system.

Gulp explores the alimentary canal, moving like a bolus of food from mouth to stomach to lower gastrointestinal tract. Along the way, Roach visits scientists studying the various elements of eating, digesting and eliminating.

Roach has an eye for the odd. Rather than write a treatise on the properties of stomach acid, for instance, she tells the story of surgeon William Beaumont and his career studying the fistulated stomach of Alexis St. Martin. An 1822 shooting accident left St. Martin with a fistula, or hole, through which the doctor could slip pieces of food and study their digestion. The rest of the book proceeds with similarly quirky research on saliva, chewing, gut bacteria and more.

Like her four previous books, Gulp is a whirlwind tour. Luckily, Roach makes you feel as if you?re on the tour bus with your funniest friend providing running color commentary. She?s completely fearless, perfectly happy to plunge her hand ? nay, her entire arm ? into a cow?s stomach to feel its digestive caress. The next thing you know, she?s off to a lab where she hopes a researcher ?might be able to whip up a batch of artificial flatus.?

Some may say it?s all a bit silly, but Roach embraces the puerile attraction of her topic. ?I don?t want you to say, ?This is gross,? ? she writes. ?I want you to say, ?I thought this would be gross, but it?s really interesting.? ? And it is. ? Erika Engelhaupt

W.W. Norton & Co., 2013, 348 p., $26.95

Source: http://www.sciencenews.org/view/generic/id/350172/title/Book_Review__BOOK_REVIEW_Gulp_Adventures_on_the_Alimentary_Canal_by_Mary_Roach

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বৃহস্পতিবার, ২ মে, ২০১৩

Miss. ricin-letters case headed to grand jury

May 1 (Reuters) - Post position for Saturday's 139th Kentucky Derby at Churchill Downs after Wednesday's draw (listed as barrier, HORSE, jockey, trainer) 1. BLACK ONYX, Joe Bravo, Kelly Breen 2. OXBOW, Gary Stevens, D. Wayne Lukas 3. REVOLUTIONARY, Calvin Borel, Todd Pletcher 4. GOLDEN SOUL, Robby Albarado, Dallas Stewart 5. NORMANDY INVASION, Javier Castellano, Chad Brown 6. MYLUTE, Rosie Napravnik, Tom Amoss 7. GIANT FINISH, Jose Espinoza, Tony Dutrow 8. GOLDENCENTS, Kevin Krigger, Doug O'Neill 9. OVERANALYZE, Rafael Bejarano, Todd Pletcher 10. PALACE MALICE, Mike Smith, Todd Pletcher 11. ...

Source: http://news.yahoo.com/miss-ricin-letters-case-headed-grand-jury-165400366.html

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Shaking things up: Researchers propose new old way to purify carbon nanotubes

May 1, 2013 ? An old, somewhat pass?, trick used to purify protein samples based on their affinity for water has found new fans at the National Institute of Standards and Technology (NIST), where materials scientists are using it to divvy up solutions of carbon nanotubes, separating the metallic nanotubes from semiconductors. They say it's a fast, easy and cheap way to produce high-purity samples of carbon nanotubes for use in nanoscale electronics and many other applications.

Carbon nanotubes are formed from rolled-up sheets of carbon atoms arranged in a hexagonal pattern resembling chicken wire. One of the amazing features of nanotubes is that, depending on just how the sheet rolls up, a quality called chirality, the resulting tube can behave either like a semiconductor, with various properties, or like a metal, with electrical conductance up to 10 times better than copper. One big issue in creating commercially viable electronics based on nanotubes is being able to efficiently sort out the kind you want.

Thinking about how to do this, says NIST researcher Constantine Khripin, brought up the subject of biochemists and so-called "two-phase liquid extraction." "Biologists used this to separate proteins, even viruses," says Khripin, "It's an old technique, it was popular in the 70s, but then HPLC [high-performance liquid chromatography] replaced a lot of those techniques." People use HPLC to partition carbon nanotubes as well, he says, but it's less successful. HPLC divides things by exploiting differences in the mobility of the desired molecules as they travel small columns loaded with tiny spheres, but carbon nanotubes tend to stick to the spheres, reducing yield and eventually clogging the equipment.

The concept of liquid extraction is relatively straightforward. You make a mixture in water of two polymers that you've selected to be just slightly different in their "hydrophobicity," or tendency to mix with water. Add in your sample of stuff to be separated, stir vigorously and wait. The polymer solutions will gradually separate into two distinct portions or "phases," the lighter one on top. And they'll bring along with them those molecules in your sample that share a similar degree of hydrophobicity.

It turns out that this works pretty well with nanotubes because of differences in their electronic structure -- the semiconductor forms, for example, are more hydrophobic than the metallic forms. It's not perfect, of course, but a few sequential separations ends up with a sample where the undesired forms are essentially undetectable.

Be honest. It's not that easy. "No," agrees, Khripin, "People tried this before and it didn't work. The breakthrough was to realize that you need a very subtle difference between the two phases. The difference in hydrophobity between nanotubes is tiny, tiny, tiny." But you can engineer that with careful addition of salts and surfactants.

"This technique uses some vials and a bench-top centrifuge worth a couple hundred dollars, and it takes under a minute," observes team member Jeffrey Fagan. "The other techniques people use require an HPLC on the order of $50,000 and the yields are relatively low, or an ultracentrifuge that takes 12 to 20 hours to separate out the different metals from semiconductors, and it's tricky and cumbersome."

"The nanotube metrology project at NIST has been around for a quite a number of years," says senior team member Ming Zheng. "It has been a constant interest of ours to develop new ways to separate nanotubes, cheaper ways, that industry can use in the development of nanoelectronics and other applications. We really think we have a method here that fits all the criteria that people are looking for. It's easy, it's scalable, it's high resolution -- all the good attributes put together."

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Story Source:

The above story is reprinted from materials provided by National Institute of Standards and Technology (NIST).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Constantine Y Khripin, Jeffrey A. Fagan, Ming Zheng. Spontaneous Partition of Carbon Nanotubes in Polymer-Modified Aqueous Phases. Journal of the American Chemical Society, 2013; : 130423102819007 DOI: 10.1021/ja402762e

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/most_popular/~3/Wv5zT60mZqw/130501145146.htm

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Lindsay Lohan takes 270 outfits to 90-day rehab

Celebs

7 hours ago

Actress Lindsay Lohan

Getty Images file

Actress Lindsay Lohan will begin a 90-day rehab stint on Thursday.

It looks like Lindsay Lohan is planning to dress for success for her sixth stint in rehab. The troubled actress, who will start her court-mandated 90-day rehab sentence on Thursday at the Morningside Recovery Center in Newport Beach, Calif., won't be traveling lightly. On Tuesday night, she posted a photo on her Instagram account of herself surrounded by luggage and clothing, along with the caption "90 days and 270 looks."

Lohan's rehab wardrobe, which would give her three separate outfits per day, will be put to good use at the rehab facility, which boasts group activities such as bowling, sporting events and even supervised barbecues on the beach.

An abundance of clothing isn't the only thing that Lohan will be bringing to the rehab facility. The actress will also have a hefty supply of cigarettes. Morningside, unlike Lohan's first choice of rehab, the Seafield Center in New York, allows its residents to smoke in designated areas, prompting Lohan to change her rehab plans and fly west.

Lohan's latest rehab sentence comes after she pleaded no contest in March to charges of lying to a police officer and reckless driving from a June 2012 car crash. In addition to her mandatory stay in a locked rehab facility, the actress must also complete 30 days of community labor, pay fines and restitution to her victim, and attend psychological counseling sessions.

For her part, Lohan seems to be taking her rehab sentence in stride. In addition to posting the funny photo (which she later deleted from her Instagram account), Lohan told David Letterman last month that she is happy to be going to a treatment center.

"I don't think it's a bad thing," she told the late-night host in April. "I think it's a blessing...and not a curse."

Source: http://www.today.com/entertainment/lindsay-lohan-bring-lots-baggage-rehab-270-outfits-90-days-6C9723651

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Finally, Phone RAM as Good as the Stuff in Your Computer

Samsung has just announced that it's rolling some pretty exciting new memory into production, which will finally bring computer-like RAM performance to your mobile.

Of course, to work that out you have to sift through all the mention of 20nm manufacturing techniques and LPDDR3 naming. What you really need to know is that it's fast: it can transmit data at up to 2,133 Mbps per pin. That's twice as fast as the previous mobile memory standard, and means it's possible to transmit three full HD videos?17GB!?in one second over the new Samsung chip when it's embedded in a phone.

It's efficient, too, with the shrinking of the chip's geometry apparently providing a 20 percent increase in efficiency. All that, and it's possible to squeeze 2GB into a stack just 0.8mm in height. Expect to see this stuff hit the next generation of super phones within the next year?and notice a big difference, too. [Engadget]

Source: http://gizmodo.com/finally-phone-ram-as-good-as-the-stuff-in-your-compute-485769569

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