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Tech Savvy.....

Tech Savvy.....: January 2009

Tech Savvy.....

All about latest trendz in Technology

Jan 15, 2009

Morphing gel display puts images at your fingertips


A tactile display made from a watery gel that changes shape to show objects on its surface has been developed by German electrical engineers.
It uses a hydrogel, the type of material used to make soft contact lenses, which consist mainly of water bound up within a polymer. Some hydrogels can swell or shrink in response to changing conditions like temperature or acidity.
Andreas Richter and Georgi Paschew from the Technical University of Dresden turned to those abilities when trying to develop a new tactile display for blind people.
"We use smart hydrogels, which can significantly change their volume and mechanical strength," Richter told New Scientist.
Light control
The two scientists created a square array of 4225 blobs of temperature-sensitive hydrogel, each approximately 300 microns across and separated from its neighbours by a similar amount. Just one square centimetre of the array contains 297 of the gel "pixels".
They sit on a black polyester backing that heats up when hit by a beam of light that is narrow enough to warm individual blobs. Below 29 °C the pixels are 0.5 millimetres tall, but if heated to 35 °C they expel some of their water and become half as tall. They also become opaque and much harder to the touch.
Rapidly scanning the light beam across the black backing makes it possible to display high-resolution, tactile images (see image, top right) that change twice a second.
Once the light beam moves away from a pixel, its temperature quickly drops and the gel swells back to its previous size, sucking up its lost water.
To bring the shape changes into sharper relief and also prevent water from escaping, the gel is sealed beneath a plastic membrane.
Surgery tool
Richter says this system could be used to make tactile displays that communicate information at a person's touch. Such displays could be for blind people, or built into the interfaces of robotic surgery equipment to let human surgeons feel what is at a robot's fingertips.
Some improvements are needed before this can become reality, such as reducing the temperatures at which the gel responds, but the team's prototype can already do most of what a display would require.
Richter is also exploring how shrinking and swelling gels could act as tiny pumps and valves for microscale lab-on-a-chip devices.
"This is a remarkable demonstration – the first – designing, engineering and optimising an integrated complex surface and an important step forward," says João Cabral, head of the polymers and microfluidics group at Imperial College, London.

Is it really bad to be sad?


WHY be miserable? OK, so it's January and you're feeling fat and broke after the excesses of the holiday season, but there's really no need. Misery is inconvenient, unpleasant, and in a society where personal happiness is prized above all else, there is little tolerance for wallowing in despair. Especially now we've got drugs for it.
Antidepressants can help banish sad feelings - not just the life-sapping black dog of clinical depression, but the rough patches that most people go through sometimes, whether it's after losing a job, the break-up of a relationship or the death of a loved one. So it's no surprise that more and more people are taking them (see graph).
But is this really such a good idea? A growing number of cautionary voices from the world of mental health research are saying it isn't. They fear that the increasing tendency to treat normal sadness as if it were a disease is playing fast and loose with a crucial part of our biology. Sadness, they argue, serves an evolutionary purpose - and if we lose it, we lose out.
"When you find something this deeply in us biologically, you presume that it was selected because it had some advantage, otherwise we wouldn't have been burdened with it," says Jerome Wakefield, a clinical social worker at New York University and co-author of The Loss of Sadness: How psychiatry transformed normal sorrow into depressive disorder (with Allan Horwitz, Oxford University Press, 2007). "We're fooling around with part of our biological make-up."
Perhaps, then, it is time to embrace our miserable side. Yet many psychiatrists insist not. Sadness has a nasty habit of turning into depression, they warn. Even when people are sad for good reason, they should be allowed to take drugs to make themselves feel better if that's what they want.
So who is right? Is sadness something we can live without or is it a crucial part of the human condition?
Hard evidence for the importance of sadness in humans is difficult to come by, but there are lots of ideas about why our propensity to feel sad might have evolved. It may be a self-protection strategy, as it seems to be among other primates that show signs of sadness. An ape that doesn't obviously slink off after it loses status may be seen as continuing to challenge the dominant ape - and that could be fatal.
Wakefield believes that in humans sadness has a further function: it helps us learn from our mistakes. "I think that one of the functions of intense negative emotions is to stop our normal functioning, to make us focus on something else for a while," he says. It might act as a psychological deterrent to prevent us from making those mistakes in the first place. The risk of sadness may deter us from being too cavalier in relationships or with other things we value, for example.
What's more, says Paul Keedwell, a psychiatrist at Cardiff University in the UK, even full-blown depression may save us from the effects of long-term stress. Without taking time out to reflect, he says, "you might stay in a state of chronic stress until you're exhausted or dead". He also thinks that we may have evolved to display sadness as a form of communication. By acting sad, we tell other community members that we need support.
Then there is the notion that creativity is connected to dark moods. There is no shortage of great artists, writers and musicians who have suffered from depression or bipolar disorder. It would be difficult to find enough recognised geniuses to test the idea in a large, controlled study, but more run-of-the-mill creativity does seem to be associated with mood disorders. Modupe Akinola and Wendy Berry Mendes of Harvard University found that people with signs of depression performed better at a creative task, especially after receiving feedback that was designed to reinforce their low mood. The researchers suggest that such negative feedback makes people ruminate on the unhappy experience, which allows subconscious creative processes to come to the fore, or that it pushes depression-prone people to work harder to avoid feeling bad in the future (Personality and Social Psychology Bulletin, vol 34, p 1677).
Don't be happy, worry
There is also evidence that too much happiness can be bad for your career. Ed Diener, a psychologist at the University of Illinois in Urbana-Champaign, and his colleagues found that people who scored 8 out of 10 on a happiness scale were more successful in terms of income and education than 9s or 10s - although the 9s and 10s seemed to have more successful close relationships (Perspectives on Psychological Science, vol 2, p 346).
This could simply demonstrate that the happiest people are those who cherish close relationships over power and success, but it could also signal that people who are "too happy" lose their willingness to make changes to their lives that may benefit them. Medicating sadness, Keedwell suggests, could do the same - blunting the consequences of unfortunate situations and removing people's motivation to improve their lives. Giving antidepressants to people whose real problem is something else - a bad relationship, for instance - may allow the person to continue in an unhealthy situation instead of addressing the underlying problem.


Whether or not a little sadness is useful, everyone agrees that clinical depression is not. Unfortunately it's not clear exactly where to draw the line between the two (see "Sad or depressed?"). So which is more dangerous: to over-medicate normal sadness, a feeling which may lead us to re-evaluate our lives after the loss of a job or the end of a relationship, or under-medicate clinical depression?
Ian Hickie of the Brain and Mind Research Institute at the University of Sydney, Australia, insists that depression is not overdiagnosed but would rather it were than see seriously depressed people left out in the cold. He points out that there is evidence to suggest that the number of suicides has declined as more cases of depression have been diagnosed. It's important to take borderline diagnoses of depression seriously, he says, because "most of the suicides do not occur in the most severely depressed".
Wakefield, however is uneasy about prescribing pills where there is no certainty that they are needed. After all, he points out, antidepressants have side effects, some of them serious.
The need for sad
So where does this leave the notion of human sadness? Should we accept that major life events may make us so sad that we are temporarily disabled? Or should we run to the doctor in the hope that pills will speed up our emotional journey back to happiness?


Ken Kendler, a psychiatrist at the Virginia Commonwealth University in Richmond, points out that for some people, sadness is definitely something they are better off without. He recalls a mother in her late 20s who came to him because she had an inoperable defect in her aorta that would rupture at some undeterminable time in the future, killing her instantly. This knowledge had made her depressed - certainly with reasonable cause - but she did not want to live the rest of her days that way, unable to function for her family.
"That seemed to me to be an irreproachable logic on her part," Kendler says. "I started her on antidepressants. She came back much brighter. The idea that I was depriving this woman of the proper grieving experience and preventing her from experiencing deeply the meaning of this rang very hollow in this particular case."
For those of us not faced with such an extreme problem, Terence Ketter, a psychiatrist at Stanford University in California, is more cautious. "The cost of happiness is complacency," he says. Sadness is still something useful: "Discontent can drive change. Certainly, you don't want to stifle or blunt emotion - emotion is information."
Keedwell agrees. "Clearly, if we didn't feel sad when we were unsuccessful at achieving certain goals, we would not stand back from that goal and introspect and perhaps try to change our strategies," he says, echoing Wakefield and the Harvard creativity study. "Being enthusiastic and jubilant we would probably go blindly on."
So is there some middle ground? Both sides agree that there are ways to lift the gloom without pills. "An alternative would be thinking about what is making you unhappy," says Wakefield. "Another possibility is watchful waiting. A more nuanced view of the situation will help people think about their options better."
Diener also suggests we stop obsessing about being happy all the time (see "A pill for every ill"). "One of the things we want to do is disabuse people of the notion that they're not happy enough," he says. He cites a study that used emotion-recognition software to work out the Mona Lisa's inner feelings (New Scientist, 17 December 2005, p 25). It concluded that she is 83 per cent happy. The rest is a mix of negative emotions like fear and anger. That, it seems, is just about right.

Jan 1, 2009

Green fuel technologies pick up speed in 2008

US president elect Obama may have appointed a "green dream team" to help him govern, but it is far from obvious how they will tackle the thorny problem of how to make our energy use more sustainable.
Yet we may already have seen the solutions, amongst the latest crop of innovations in green fuels. Here's a reminder of the discoveries from the past year that may revolutionise the way we power our lives.
Greener gas
Making cars greener does not require complex new ideas. Norwegian researchers reported that simply switching from gasoline to clean diesel could cut CO2 emissions by a quarter.
Cleaning existing fuels more thoroughly before they reach cars could make a difference too. In October, came the announcement that a humble fungus can strip crude oil of the harmful sulphur and nitrogen compounds that cause air pollution and acid rain.
And that's not the only fungus that could help cut drivers' carbon emissions. The following month a newly discovered Patagonian strain was shown to convert plant waste directly into diesel - a finding that could produce cheap biofuels without sacrificing arable farm land.
Fuel and food
The tricky problem of making sure that biofuels are not produced at the expense of food yields was addressed in other ways.
Photosynthetic algae offer one plausible solution, because they can produce biofuels without impacting farm land at all.
Meanwhile, the Holy Grail of biofuel production - cheap ethanol from waste plant material - received a boost in April, in the form of a self-digesting variety of genetically modified corn.
After the cobs have been harvested, and the remainder of the plant crushed, enzymes produced by genes from a bacterium digest it from the inside out. This breaks down the cellulose-rich stems and leaves that are a waste product of so many crops.
Even the lignin that gives woody material its toughness can now be converted into fuel. In July, researchers announced a new chemical reaction able to do just that, proving it worked by converting sawdust into the chemical precursors of biodiesel.
Electric dreams
Electric cars were also subject to feverish new developments, most focused on improving their range to make them more competitive with conventional vehicles.
One approach is to replace batteries with ultracapacitors, which store power as electrical rather than chemical energy, and can be charged almost instantaneously. A new type, based on carbon nanotubes and manganese oxide "flowers", stores twice as much charge as existing ultracapacitors, and might power electric cars in the years to come.
Batteries and ultracapacitors alone still look unlikely to cram quite as much mileage into the space of a fuel tank as a liquid fuel can. However, a novel design that is part fuel cell, part battery proved able to pack in energy twice as densely as petrol can.
Hybrid vigour
In the short term, hybrid systems that combine electric and internal combustion engines are likely to remain the most efficient, and most sustainable, way forward for road vehicles.
The technology received a boost in October with news of a new "UltraBattery" that produces 50% more power than traditional lead-acid batteries while lasting four times as long. It doesn't become clogged with deposits during the repeated charging and discharging that occurs in a hybrid constantly switching from burning fuel to using electricity.
Finally, although years of investment in hydrogen cars by the largest car manufacturers has yielded little more than a few prototypes, our in-depth report concluded it might be too early to sound the death knell for the hydrogen economy.
Car makers continue to invest, despite diverting resources towards electric cars. And research into storing hydrogen more densely and safely continues. A novel spongy but tough material unveiled in October is capable of exceeding a target set by the US Department of Energy for hydrogen storage density.
Were that technology to be developed into fully fledged fuel tanks, one obstacle preventing fuel cells revolutionising motor transport would have been removed.
Before that happens, however, the cost of fuel cells needs to be reduced - they currently rely on expensive platinum catalysts. A low cost, precious metal-free fuel cell announced in late December could solve that problem