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Sunday, July 20, 2008

Human blood vessels grown in mice

Capillary
The structure of blood vessels is complex

Scientists have used human cells to grow new blood vessels in a mouse for the first time, a US journal reports.

It could eventually help patients who had suffered heart attacks, they said.

A mixture of "progenitor" cells, taken from blood and bone marrow, made cells lining the vessels, and also those surrounding the lining.

A UK expert said that the Harvard research was "promising", and could eventually help lab-grown organs to be implanted successfully.

The ability to develop swiftly a new network of tiny blood vessels - known as capillaries - would be a prize for scientists.

There are dozens of potential applications in medicine, particularly in the treatment of conditions which involve damage to a tissue's blood supply, such as that to the heart muscle following a heart attack.

However, the complex structure of these vessels has slowed progress.

What's really significant about our study is that we are using human cells that can be obtained from blood or bone marrow rather than removing and using fully developed blood vessels
Dr Joyce Bischoff
Harvard Medical School

The latest study, published in the journal Circulation Research, uses two types of "progenitor" cells, which have the ability, like stem cells, to form different cell types.

In this case, "endothelial" progenitor cells have the ability to form the cells which line blood vessels, while "mesenchymal" progenitor cells can form the cells adjacent to this lining, which help to support it.

Unlike more controversial stem cell therapies, which might require cells taken from an embryo, these progenitor cells can be harvested from the blood or bone marrow of an adult, or from the umbilical cord.

They were mixed together in growth-promoting chemicals in the laboratory, then implanted into mice whose immune systems had been weakened to avoid rejection.

Pig progress

Within seven days, a "vigorous network" of new vessels formed, joined up with the host animal's blood vessels and started transporting blood.

Dr Joyce Bischoff, who led the research team, said: "What's really significant about our study is that we are using human cells that can be obtained from blood or bone marrow rather than removing and using fully developed blood vessels."

Dr Nick Rhodes, from the UK Centre for Tissue Engineering at the University of Liverpool, said that the results were "interesting and promising".

He said: "It could certainly assist in the connection of other engineered organs to the body's blood supply.

"Although this approach is not yet suitable for clinical use, it is interesting that they have demonstrated you have all the elements you need to create a functional network of capillaries from a small amount of blood."

Original here

"Sleepless" Mutation Found Responsible for Sleeplessness

Insomnia Though you might take mild offense at being compared to a fly, a new scientific discovery may provide a clue as to why humans and animals alike experience insomnia. A new genetic mutation found in flies can cause 80% less sleep than normal flies, forcing the flies to get by with much less sleep.

The mutation, now dubbed Sleepless, suggests that at our most basic level, sleep is caused by a slowdown in certain neurons. And according to Amita Seghal, a neurobiologist at the University of Pennsylvania in Philadelphia, who led the new study, an inability to control these neurons may be the cause of restless nights.

"When you're having a bad night of insomnia you do have the need to sleep, but you're not able to," she says. "That might be what’s going on with these animals."

Though a normal fly manages to sleep for around 12 hours a day, those flies with a broken Sleepless only get one or two hours; however they don’t realize they’ve lose sleep. "When you deprive them, you're not really taking away any sleep, because there wasn’t any to begin with," Sehgal says. However as a result, their lifespan shortens and their coordination is impaired.

Another side effect of the Sleepless mutation occurred when the flies were knocked out with ether. When knocked out by the drug, the flies legs began to twitch reflexively, an effect similar to that of another gene mutation that influences sleep patterns by regulating cell communication.

From this, Sehgal hypothesizes that Sleepless controls a brain cell slow-down that she believes may be the very essence of sleep. Thus, if Sleepless isn’t working properly, neural activity goes banana’s, which then causes the twitching legs. This may very well link to the common problem many of us face, known as restless legs syndrome, or for those of us not in a laboratory, jumpy legs.

Posted by Josh Hill.

Original here

MIT Students Develop Solar Dish Hot Enough to Melt Steel

MIT Students Develop Solar Dish Hot Enough to Melt Steel

The dish is composed of a set of 10 inch by 12 foot curved mirrors, like the one seen here. The students easily mount the mirrors to the aluminum framework using simple hardware like washers and zip ties. (Source: MIT)

‘New solar dish from MIT concentrates sunlight intensely enough to melt steel.’ -

The solar industry is booming. With waves of investment and grants, the solar power industry is for the first time becoming a serious business. New power plants will soon be pumping power out to consumers, while other firms market to sell panels directly to the consumer, providing them with a more direct means of experiencing solar energy.

There are many forms of solar power technology. Today the most dominant is photo-voltaics , which comprise the traditional solar panels that come to mind when one thinks of solar power. However, there are other promising ways of capturing the sun’s energy that are merely less developed.

Among these is a parabolic collector. A parabolic collector consists of an array of mirrors focused on a singular point, which they heat to a high temperature. By placing water or another liquid at the collector, energy can be stored in the form of a phase transformation, and later harvested through a turbine generator.

However, parabolic collectors are still a relatively new field of research. Their true potential remains relatively unknown. A glimpse of it was provided by a research team at MIT, which developed a new parabolic collector design, which will blow away current solar power designs in terms of efficiency.

The MIT team believes that their lightweight, inexpensive device holds the promise of revolutionizing the power industry and providing solar power to even remote regions.

The key piece is the 12-foot dish, which the team assembled in several weeks. The design is exceedingly simple and inexpensive. The frame is composed of aluminum tubing and mirrors are attached to it.

The results are staggering – the completed mirror focuses enough solar energy at its focal point to melt solid steel. The energy of typical sunlight is concentrated by a factor of 1,000. This was showcased during a demonstration, in which a team member held up a board, which instantly and violently combusted, when brought within range of the focal point.

By directing the dish at a more practical target – water piped through black tubing – steam can be flash created, offering instant means of producing energy or providing heating.

Spencer Ahrens, who just received his master’s in mechanical engineering from MIT, was among the designers of the dish. He and his fellow team members are serious about marketing it, and leveraging its cheap cost and easy production. They have founded a company named RawSolar. They say their design is easily mass producible and that they hope to be pumping out 1,000 of dishes in years to come.

The new dishes would return their costs in a mere couple years, unlike standard photo-voltaic installations which can take 10 years or more to return their costs. This improvement is critical to providing practical economic justification for adoption.

The dish is based partly on components invented and patented by inventor Doug Wood. He was so pleased with the team’s work that he signed over rights to the components to the team. He elates, “This is actually the most efficient solar collector in existence, and it was just completed. They really have simplified this and made it user-friendly, so anybody can build it.”

8452_mirror_2_max200w

The mirrors incredible power makes short work of a beam of wood, disintegrating it in flames and smoke. The focal point can melt steel. (Source: MIT)

Wood says one of the keys to the success of the project is the smaller size. Dishes are affected by the same weight dynamics that effect living organisms. Much as large living organisms would need an inordinate amount of weight support and thus are not favored, larger dish designs fall short in that they require an exponentially greater amount of infrastructure. For example, a dish the size of the RawSolar team’s design costs only a third of what a larger dish would cost.

MIT Sloan School of Management lecturer David Pelly gave a guiding hand to the students and thinks the economic upsides of the technology are impressive. He states, “I’ve looked for years at a variety of solar approaches, and this is the cheapest I’ve seen. And the key thing in scaling it globally is that all of the materials are inexpensive and accessible anywhere in the world. I’ve looked all over for solar technology that could scale without subsidies. Almost nothing I’ve looked at has that potential. This does.”

The ability to build unsubsidized, profitable, and easy to manufacture solar power will truly be something amazing. This should be an exciting technology to follow as it is marketed and further developed.

Besides Ahrens, the other students primarily working on the project were Micah Sze (Sloan MBA ‘08), UC Berkeley graduate and Broad Institute engineer Eva Markiewicz, Olin College student Matt Ritter and MIT materials science student Anna Bershteyn.

Original here

Rumor Debunked: No Flip-Flop on Global Warming

By Andrea Thompson, Senior Writer

Claims are floating around the blogosphere that the American Physical Society, the leading professional organization for physicists, has reversed its position on global warming.

But on its Web site, the APS has reaffirmed that it supports the consensus view that human-caused greenhouse gas emissions are warming the planet.

Part of the statement the society adopted on Nov. 18, 2007, states: "Emissions of greenhouse gases from human activities are changing the atmosphere in ways that affect the Earth's climate."

Stories of the supposed policy reversal began popping up after an article by Christopher Monckton, a politician and a former policy advisor in Margaret Thatcher's administration, submitted an article in an online newsletter of the APS Forum on Physics and Society. The article claimed that the Intergovernmental Panel on Climate Change (IPCC) had overestimated the Earth's climate sensitivity to carbon dioxide (or how much the global average temperature will change given a certain amount of carbon dioxide entering the atmosphere).

In the article, Monckton, the 3rd Viscount Monckton of Brenchley, also claims that changes in solar activity are behind the warming trend of the past few decades, an idea that has been refuted by several climate scientists.

A note in red lettering above the article states that it has not been peer-reviewed and that "its conclusions are in disagreement with the overwhelming opinion of the world scientific community. The Council of the American Physical Society disagrees with this article's conclusions."

On their homepage, the APS has now placed a statement that reaffirms its 2007 position statement on global warming, which also states, "The evidence is incontrovertible: Global warming is occurring." It adds that mitigation efforts must be taken immediately.

Original here