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‘Mother’ of skin cells found
Prof Yash
Pal
THIS UNIVERSE
Unravelling why silk is super strong
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‘Mother’ of skin cells found
Scientists have found the “mother”, or origin, of all skin cells and say their discovery could dramatically improve skin treatments for victims of serious wounds and burns.
Hans Clevers and a team of Dutch and Swedish researchers conducted a study in mice and found that the stem cell that gives produces all the different cells of the skin actually lives in hair follicles. The findings, which they say will translate for human use, mean it may be possible to harness these stem cells to help with wound repair or skin transplants for burns victims, they said in a study in the Science journal on Thursday. “This is the mother of all the stem cells in the skin-it makes all the other stem cells,” Clevers, of the Royal Netherlands Academy of Arts and Sciences in Utrecht, told Reuters in a telephone interview. “The same stem cells exist in humans, we can see them, and the promise is that these cells are probably going to be much better than anything we have had to date at making new skin.” The skin has three different populations of cells-hair follicles, moisturising sebaceous glands, and the tissue in between, known as the interfollicular epidermis. Stem cells are original cells, or drivers, from which all human cells develop. Scientists had previously thought that stem cells in each of these three skin populations were capable of producing their own cell type, but until now, a “mother” stem cell which produces all three types had not been found. Clevers’ team found that a group of stem cells that live in hair follicles and which have high levels of a gene called Lgr6 are the original epidermal stem cells. In tests on mice with wounds, they found that Lrg6 cells around the wound drove new skin growth and repaired the skin. Scientists are already able to grow new skin in laboratories using tissue from existing skin cells from patients who have been badly burned, but the new skin is often brittle, dry and does not have hair-making it look unusual. Clevers said the advantage offered by the “mother” stem cell finding would be that they could grow skin from its original basis-allowing it to be “real new skin” with moisture from sebaceous glands and the ability to grow hair. He said researchers now need to learn how to isolate the Lrg6 cells from human skin. That could take 2 to 3 years. “We are learning how to grow the mouse cells in culture. Once we know how to do this and can isolate the human variant, we should be able to grow human cells as well,” he said. “Since there is a lot of experience already with growing and transplanting skin for burn wound patients, it should be relatively easy to incorporate the new stem cells ... and conduct trials in patients.” |
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Trends
WASHINGTON: People leave more than fingerprints when they touch stuff-they also deposit a tell-tale trail of germs that could help investigators solve crimes, U.S. researchers reported. They were able to map a unique bacterial genetic signature left by nine different people, and said this germy DNA lasted though day-to-day temperature changes, humidity and sunlight.
New way to help crops fight pests LONDON: An international team of scientists has managed to transfer disease resistance from one plant family to another, offering broader protection from potentially costly and destructive pests. A team led by Cyril Zipfel at Britain’s Sainsbury Laboratory found that transferring a single gene from a wild plant to disease-susceptible crop plants made them more robust against infections like bacterial wilt and other diseases.
Dogs domesticated in Middle East, not Asia LOS ANGELES: From French poodles to German shepherds, domestic dogs likely trace most of their ancestry to the Middle East, as opposed to East Asian origins suggested by previous research, a genetic study reported on Wednesday. The findings, published in the online edition of the scientific journal Nature, support an archaeological record that closely links the domestication of dogs in the Middle East with the rise of human civilization there, scientists said.
SpaceX Falcon 9 test fire a success CAPE CANAVERAL, Florida: Space Exploration Technologies successfully test fired its Falcon 9 rocket, clearing a milestone toward the inaugural flight of a privately developed spaceship to fly cargo, and possibly astronauts, into orbit, the company said. Saturday’s 3.5-second ‘static’ firing of the Falcon’s nine kerosene and liquid oxygen-burning motors took place on a refurbished oceanside launch pad at Cape Canaveral Air Force Station in Florida. It followed an earlier firing test aborted last week.
— Reuters and AFP |
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THIS UNIVERSE
Why does the speed of light not vary when it comes out of any heavenly object with the escape velocity near to (but less than) that of the speed of light?
The speed of light in vacuum is constant. Indeed it is a constant of Nature. The kind of argument that led Einstein to propose this was the following: He argued that if someone were to ride a light beam, the light would look to him nothing more than an oscillating electromagnet field that was fixed in space. Such a phenomenon contradicted the electromagnetic theory of Maxwell, besides being observationally untenable. In the example you have suggested even though light comes out at the same velocity, its energy and momentum is changed by the velocity of the source. The Special Theory of Einstein ensured that the energy momentum relations are upheld in the universe in which light velocity is held constant. That is a fundamental requirement of physics. When liquid is poured down, it twists. Why? When you pour out some liquid, several things happen. Let us remember that the liquid consists of molecules that fall down one after the other. This first molecule begins accelerating while it is still held by the sender and later molecules by force of adhesion. The force of gravity and the adhesive force are not necessarily exactly in opposite direction. So some twisting force could remain. The molecules that come out first start moving faster as they descend. At some point even the closest molecules may have different velocities. Then we get a spray. Many different scenarios develop depending on the number of molecules together at different instants of this dynamic phenomenon. Have you ever seen the way the twisting, accelerating mass of children descend a staircase when the last bell of the school sounds? Why did Einstein’s equation E=mc2 become so famous though no one has seen mass changing to energy? Where did the atoms of matter go after being converted to energy? Can energy be converted into mass? How? Why is everything symmetrical? You are wrong. Mass does change into energy. That is how the sun shines. That is why nuclear bombs are so powerful. Energy changing into mass is also observed. Do not be so sceptical. Please do some reading. Readers wanting to ask Prof Yash Pal a
question can e-mail him at palyash.pal@gmail.com |
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Unravelling why silk is super strong
Scientists have untangled some of the most closely guarded secrets of silk and explained why it is so super strong. Researchers at the Massachusetts Institute of Technology’s (MIT’s) Center for Materials Science and Engineering say the key to silk’s pound-for-pound toughness, which exceeds that of steel, is its beta-sheet crystals, the nano-sized cross-linking domains that hold the material together.
Markus Buehler, the Esther and Harold E. Edgerton Associate Professor in MIT’s department of civil and environmental engineering, and his team recently used computer models to simulate exactly how the components of beta sheet crystals move and interact with each other. They found that an unusual arrangement of hydrogen bonds — the “glue” that stabilises the beta-sheet crystals — play an important role in defining the strength of silk. They found that hydrogen bonds, which are among the weakest types of chemical bonds, gain strength when confined to spaces on the order of a few nanometers in size. Once in close proximity, the hydrogen bonds work together and become extremely strong. Moreover, if a hydrogen bond breaks, there are still many hydrogen bonds left that can contribute to the material’s overall strength, due to their ability to “self-heal” the beta-sheet crystals. The researchers concluded that silk’s strength and ductility - its ability to bend or stretch without breaking - results from this peculiar arrangement of atomic bonds. They said that controlling the size of the area in which hydrogen or other chemical bonds act can lead to significantly enhanced properties for future materials, even when the initial chemical bonds are very weak.—ANI |
People leave unique trail of germs
