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Tuesday, 4 November 2008

Newest and coolest

In today's edition:

  1. Paraplegics take first steps with robotic legs
  2. A New Flexibility With Thin Solar Cells
  3. Polygamy left its mark on the human genome
  4. Hiding magnets in blood brings scans into focus
  5. Transplanted frozen liver raises hopes of organ 'bank
  6. A taste for scorpion venom could be cancer's undoing
A special attention to articles no. 5 and 6 since they can lead to a major break-trough in medicine and that's what we all will like after all. Enjoy!

Paraplegics take first steps with robotic legs

Movie Camera
  • 13:17 26 August 2008

Paralyzed for the past 20 years, former Israeli paratrooper Radi Kaiof now walks down the street issuing a faint mechanical hum.

That is the sound of an electronic exoskeleton that moves the 41-year-old's legs and propels him forward.

"I never dreamed I would walk again. After I was wounded, I forgot what it's like," said Kaiof, who was injured while serving in the Israeli military in 1988.

The device, called ReWalk, is the brainchild of engineer Amit Goffer, founder of Argo Medical Technologies, based in Israel.

ReWalk consists of motorised leg supports, body sensors and a back pack that contains a computer and rechargeable batteries. Users still need crutches to help with balance.

Goffer himself became paralysed in an accident in 1997, but because he lacks full use of his arms cannot use his own invention.

To move, the user picks a setting with a remote control wrist band – "stand", "sit", "walk", "descend" or "climb" – and then leans forward, activating the body sensors and setting the robotic legs in motion.

ReWalk is in clinical trials in Tel Aviv's Sheba Medical Centre, with more scheduled at the Moss Rehabilitation Research Institute in Pennsylvania, US.

Other robotic exoskeletons, like those being developed by the US military or the HAL robot developed at Japan's University of Tsukuba, are not suitable for paralyzed people, Goffer says.

HAL and other exoskeletons are usually aimed at boosting the strength of fully mobile people, such as soldiers carrying heavy loads or elderly people with failing strength.

To demonstrate the power advantage given by such suits, two mountaineers have used versions of HAL to carry two other people to the summit of the Breithorn in Switzerland.

And in May, US firm Berkeley Bionics started accepting pre-orders for an exoskeleton it claims can allow a person to walk normally while carrying 90 kilograms of weight.

ReWalk is slated for commercial sale in 2010 at $20,000 – a price competitive with the more sophisticated wheelchairs on the market, the company says.source

My comment: Isn't it great to read about such news?! I watched in a tv-show a man who had his fingers cut after a car-crash on -15oC. It was very sad to see the young man handicapped, but still, he found the inner strength to work out and make a life for himself. I just cannot understand why such innovations are so slow to go to the market when they cannot do harm and will improve the life of so many people.

A New Flexibility With Thin Solar Cells


October 6, 2008

Photovoltaic cells, the basic building blocks of solar panels, are more efficient and less costly than ever. But manipulating cells (which are usually made of semiconductor materials) and incorporating them into different panel designs is not necessarily easy.

John A. Rogers of the University of Illinois, Urbana-Champaign, and colleagues have come up with a novel method for creating extremely thin solar cells that can be combined in flexible, even partially transparent, arrays. Described in Nature Materials, it could be called the rubber-stamp approach.

The technique involves creating a series of precisely spaced “microbars” on a block of single-crystal silicon. These bars, which have a thickness of a few micrometers, have doped regions that create p-n junctions, the main feature of most photovoltaic cells.

Through an etching process, the bars are undercut so they can be lifted off the remaining silicon using a block of rubbery material. They can be transferred to a substrate of another material, and this transfer-printing process can be repeated many times to build a cell. A metal grid is overlaid to create electrical connections.

The technique may allow the fabrication of solar arrays with a variety of characteristics. For example, the researchers say it would be possible to print the cells on rollable plastic sheets that would be easy to transport and install. Or by printing the cells on glass in different densities, solar arrays could be incorporated into windows that have a specific level of transparency. source

My comment:This certainly starts to resemble more and more to some sci fi novel. Just imagine the new possibilities this tecnique offers! Windows that produce energy! Awesome, eh?

Polygamy left its mark on the human genome

  • 01:00 26 September 2008

Throughout human history, relatively few men seem to have had a greater input into the gene pool than the rest, suggests a study of variations in DNA.

Tens of thousands of years of polygamy has left a mark on our genomes that is a signature that small numbers of males must have mated with lots of females.

Over time, such a pattern will spawn more genetic differences on the X chromosome than other chromosomes. This is because women have two copies of the X, while men only one. In other words, the diversity arises because some men don't get to pass on their genes, while most women do.

Polygyny refers to the practice of males mating with multiple females, and its most common form in humans is polygamy or multiple marriages.

To find our hidden genetic history, Hammer and his colleagues sequenced DNA from 90 people belonging to six groups: Melanesians, Basques, Han Chinese, as well as three African cultures: Mandenka, Biaka and San.

Hammer's team discovered more genetic differences in the X chromosome than would be expected if equal numbers of males and females tended to mate, over human history. The only explanation for this pattern is widespread, long-lasting polygyny, he says.

His team's analysis reflects all of human history, and modern monogamy has not even left a blip in our genomes. "I don't know how long monogamy has been with us," Hammer says. "It seems it hasn't been around long, evolutionarily."

Besides, "most societies practice some form of polygamy", he says. Even if most Western men don't take multiple wives, men tend to father children with more females than females do with males, a practice called "effective polygamy".

Journal reference: PLoS Genetics (DOI: 10.1371/journal.pgen.1000202) source

My comment: Interestingly enough, they studied only closed groups. Sure, that way it would give better statistics and probably is a good approximation since in the past, most villages were more or less closed. Anyway, I think monogamy is nonsense anyway.

Hiding magnets in blood brings scans into focus

  • 07 October 2008
  • Linda Geddes

SURGEONS about to perform delicate operations on the heart or major blood vessels need the clearest pictures they can get. Magnetic nanoparticles injected into the bloodstream will help reveal fine details on MRI (magnetic resonance imaging) scans - but there's a snag. The particles quickly accumulate in the liver, which then removes them from the body.

Now Mauro Magnani of the University of Urbino in Italy and his team have found a way to get the tiny particles to spend longer in the bloodstream, by hiding them inside living red blood cells.

To do this, the team first immerse the blood cells in a watery solution, which causes them to swell. This opens pores in their membranes, allowing nanoparticles to drift into the cells. They become trapped when the cells are returned to a solution more like blood and the pores close up again (Journal of Nanoscience and Nanotechnology). source
My comment: As always, Nature seems to be smarter than all of us. But I like how technologies get immersed in it not only literally. Of course, it's hard to come up with something better than what the Nature made herself, but at least, we can study from her.

Rat brains show robots the way

  • 01 October 2008

A car fitted with a navigation system inspired by a rat's brain has successfully mapped a 66-kilometre road network in a suburb of Brisbane, Australia. Built by Michael Milford and Gordon Wyeth at the University of Queensland in St Lucia, the system is designed to give future autonomous robotic vehicles the ability to explore and map their environment.

At its heart is a neural network that mimics the way a rat makes a mental map of an area as it scurries through it - a concept known as simultaneous localisation and mapping. Specialised neurons in a rat's brain called "place", "head-direction" and "grid" tell the animal what direction it is facing and if the environment is a familiar one. Neural networks inspired by rat brains have previously been used to guide robots around simple lab mazes, but Milford and Wyeth's is the first to mimic the way grid neurons cope with an unfamiliar environment.

Running on a computer with a webcam feeding it video as the car drives around, the neural network maps an area by looking for landmarks such as junctions, trees and buildings, and recording the direction it is facing when it sees them. When it revisits an area and recognises a slightly altered view of a familiar landmark, it looks back over other landmarks it has recently passed to confirm its location, and updates its map accordingly. source

My comment: See my previous comment. The funniest part is that this is more or less the most natural way to orient and yet, we find it out lastly? Yeah, yeah, programming of natural things isn't a piece of a cake, but still.

Transplanted frozen liver raises hopes of organ 'bank'

  • 03 October 2008

A "BANK" of donated organs ready for use is one step closer thanks to the successful freezing, thawing and transplantation of a pig's liver. If human livers, which are about the same size, can survive this process, more people in need of transplants could receive them.

Donated livers deteriorate rapidly without a blood supply, becoming useless between 12 and 24 hours later, so getting them to recipients on time is a logistical nightmare.

Amir Arav, who pioneered the new freezing method at the Israeli Agricultural Research Organization in Bet-Dagan, says the key to limiting cell damage during freezing is to cool the liver very slowly, as this prevents the formation of jagged ice crystals. Some frog species employ a similar technique when they allow parts of their bodies to freeze during hibernation. "We didn't invent this process, nature did," says Arav.

Some frog species employ a similar technique when they allow parts of their bodies to freeze during hibernation

Arav and his colleagues flushed the blood from the pig's liver, cooled it, and then encased it in a pair of hollow brass cooling blocks attached to a supply of liquid nitrogen. The device was developed by Core Dynamics, a company Arav co-founded in Ness Ziona, Israel. This cooled the liver at a rate of 0.3 °C per minute bringing it to a temperature of -20 °C in about an hour and a half.

The team then immediately let the liver thaw for 20 minutes before transplanting it into another pig, plumbing it in as a second liver. There it rapidly recovered its red colour, an indication of blood flowing through it, and began producing bile - both signs of health and normal function. The pig was then killed after about 2 hours and the auxiliary liver analysed, revealing that the cells were alive (Rejuvenation Research, DOI: 10.1089/rej.2008.0706).

Liver researchers welcome the work, but say it would be more convincing if Arav's team had left the liver in the pig for longer and disconnected the existing organ, forcing the auxiliary to take over.

Arav says he was not allowed to do more than a temporary piggyback transplant because of restrictions imposed by animal welfare regulators, but he hopes the positive results from this limited experiment will allow the restrictions to be eased. "We hope to repeat it and do those other tests next time," he says. He plans to evaluate how long livers can be stored, as well as the optimal storage temperature.

The team also found that rat livers stored at -80 °C for up to three weeks regained function, although they were not transplanted into living animals. Arav has also frozen rat hearts, human ovaries connected to fallopian tubes, and parts of human knee joints. He has successfully transplanted the joints into about 20 people. source

My comment: Now, that's awesome! I really mean it! If you can freeze and thaw living matter without killing it, that gives a whole new perspective on freezing people with diseases for example. While I'm not sure whether I'd prefer to be frozen or to die and reincarnate, I'm sure many people will love it. And even if we live this aside, this is a new level of mastering the living matter!

A taste for scorpion venom could be cancer's undoing

  • 02 October 2008

RADIOACTIVE scorpion venom sounds like the ultimate doomsday weapon but it is now being tested as a treatment for malignant brain cancer.

The scorpion Leiurus quinquestriatus lives in the Middle East. Among the powerful cocktail of neurotoxins packed into its venom is a peptide that is non-toxic to humans and binds to a receptor found only on some tumour cells. In culture, the peptide has invaded tumours in breast, skin, brain and lung tissue, but left healthy cells untouched. "It's as if the tumours collect it," says Michael Egan of the company TransMolecular in Cambridge, Massachusetts. To see if the peptide could deliver lethal doses of radioactivity to cancer cells, researchers at the company have attached radioactive iodine isotopes to it.

In a trial last year, they injected this agent directly into the tumours of 59 people suffering from inoperable brain cancer. All the patients have now died, but those receiving a higher dose lived for three months longer, on average.

In recent weeks, researchers at the University of Chicago in Illinois have begun injecting TM601 into the bloodstream of people with different types of malignant brain cancer. This latest trial will allow the company to test whether TM601 can seek out and kill secondary tumours throughout the body, as well as known primary ones. source

My comment:Nice! Really nice. It's hard to comment until we see more details, but when you hear "it's like tumors collect it", it's enough to make your day. Especially if the same tumours then happily die while healthy cells live on.

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