Monday, 30 March 2009

Plastic containers could contaminate drinking water

Potent, man-made hormones could be leaching out of plastic water bottles into bottled drinking water, German researchers have found.

In an analysis of 20 brands of mineral water available in Germany, researchers from the Goethe University detected estrogen contamination in 60 percent of the samples.

Estrogen functions as the primary female sex hormone. In humans, it promotes the formation of breasts and is used in some oral contraceptives.

The researchers tested the extent and effect of estrogen contamination by breeding New Zealand mud snails in both plastic and glass water bottles.

Mud snails in plastic bottles were found to produce more than double the number of embryos of those in glass bottles.

Specifically, one third of the glass bottled samples showed what researchers called 'significant hormonal activity', compared with nearly 80 percent of water in plastic bottles.

More information is available from Martin Wagner and Jörg Oehlmann's online journal article.


Thursday, 26 March 2009

Scientists scavenge power from body movements

Researchers have developed a minuscule generator that converts energy from the slightest of movements into usable electricity.

The nanogenerator consists of zinc oxide nanowires, and is based on a phenomenon called piezoelectricity.

Piezoelectric properties of zinc oxide causes the material to generate an electric current when subjected to mechanical stress.

Scientists plan to embed the nanowires in clothes, shoes and even human muscles to harvest energy from users' movements.

The technology is expected to hit the market in five years' time, after the Georgia Tech research team resolves issues to do with increasing the generator's output voltage.

More information is available from Liz Tay's article on


Wednesday, 25 March 2009

Directing kids not just wasted breath

Frustrated parents rejoice: instructions to toddlers may not just be going 'in one ear, out the other' after all.

According to psychologist Christopher Chatham, young children tend to store instructions and recall them after the fact, rather than act on them instantly.

"For example, let's say it's cold outside and you tell your three-year-old to go get his jacket out of his bedroom and get ready to go outside," said Chatham, who is a doctoral student at the University of Colorado at Boulder.

"You might expect the child to plan for the future, think 'okay it's cold outside so the jacket will keep me warm'," he explained.

"But what we suggest is that this isn't what goes on in a three-year-old's brain. Rather, they run outside, discover that it is cold, and then retrieve the memory of where their jacket is, and then they go get it."

With psychology professor Yuko Munakata, Chatham conducted a study of three-and-a-half to six year olds.

The children were presented with a computer game that required them to press a button when the image appeared on screen.

Meanwhile, the researchers measured the diameter of the pupil of each child's eye to determine the mental effort of the child.

While older children completed the tasks relatively effortlessly, preschoolers were found to have more difficulty.

"The older kids found this sequence easy, because they can anticipate the answer before the object appears," Chatham said.

"But preschoolers fail to anticipate in this way. Instead, they slow down and exert mental effort after being presented with the [image], as if they're thinking back to the character they had seen only after the fact."

The researchers concluded that young children neither plan for the future nor live completely in the present. Instead, they call up the past as they need it.

More information is available from the University of Colorado's press release.


Thursday, 19 March 2009

New fingerprinting technology heats up forensics

Two student scientists have developed a new fingerprint imaging technique that uses heat to produce images cheaply and effectively.

While current methods rely on dyes and chemicals to stain fingerprints, the new technique requires only the application of heat to produce images in a matter of seconds.

The technique was accidentally discovered by honours students Adam Brown and Daniel Sommerville, both of the University of Technology, Sydney.

"Originally the aim was to make fingerprints coloured using chemicals," said Brian Reedy, a senior lecturer at the University, "but the students noticed that the application of heat alone could actually develop fingerprints."

"Our team refined the thermal technique, exposing fingerprints to hot air with temperatures of up to 300 degrees Celsius for periods of 10 to 20 seconds, which produced well-defined images."

"We also observed that after shorter heating times, fluorescent prints could be observed," he said.

Besides Brown and Sommerville's work, there has been little research done regarding the application of heat to fingerprints to date, as heat generally is considered impractical and inferior to other fingerprint imaging techniques, Reedy explained.

More information is available from the University of Technology, Sydney's press release.


Tuesday, 17 March 2009

Silicon-organic hybrid material could speed Internet access

A newly developed silicon-organic hybrid material could be key to superfast, all-optical networks of the future, researchers say.

The material combines silicon with a small organic molecule called DDMEBT that enables light-to-light interactions due to its nonlinear properties.

Materials are said to exhibit a ‘nonlinear optical response’ if their properties are affected by the intensity of light, which in turn affect how the light propagates.

This nonlinear response enables the light-to-light interactions necessary for data processing in all-optical networks.

Because DDMEBT is difficult to flexibly structure into optical circuitry, the researchers have combined it with silicon technology.

Similar to how snowflakes during a heavy storm tend to fill all the gaps between bricks, the small DDMEBT molecules are deposited into gaps between separate silicon waveguides on an integrated optical circuit.

These slots measure only tens of nanometres wide and control the propagation of light beams.

“With pure silicon,” explained Lehigh University physicist Ivan Biaggio, "you can build waveguides that enable you to control light beam propagation, but you cannot get ultrafast light-to-light interaction.”

"We need higher-speed switching to achieve a higher bit rate. Organic materials can do this, but they are not terribly good for building waveguides that control propagation of tightly confined light beams."

"We have combined the two approaches," he said in a press release.

"We start from a silicon waveguide designed to guide the light between two silicon ridges. Then we use molecular beam deposition to fill the space between the ridges with the organic material [DDMEBT], creating a dense plastic with high optical quality and high nonlinearity where the light propagates.”

The resultant device is said to demonstrate the best all-optical demultiplexing rate yet recorded for a silicon-organic hybrid device.

Demultiplexing is the process of deciphering and splitting a combined signal into its component data streams.

More information is available from Lehigh University’s press release.


Friday, 13 March 2009

A drug to end fear

Scientists may be a step closer to eliminating the emotional fear response by using a drug called propranolol.

In a recent study, psychologist Merel Kindt and a team of researchers from the University of Amsterdam showed images of two different spiders to 60 human volunteers.

One of the images was accompanied by a mild electric shock until the volunteers learned to exhibit fear and anxiety for the spider even without the shock being administered.

The following day, some of the volunteers were administered propranolol, while a control group of volunteers was given a placebo. The volunteers were then showed the spider images again.

While no difference was found between the fear response of the control group and those who had taken propranolol initially, differences became apparent on the third day.

On the third day, those who had received propranolol were found no longer to exhibit a fear response on seeing the spider, unlike those who had received the placebo.

While the volunteers could remember the association between the spider and the pain of an electric shock, this was found no longer to elicit any emotional response.

The researchers plan to investigate the long-term effects of administering propranolol, which currently is used to treat high-blood pressure.

They expect their results to contribute to a new procedure for the treatment of patients with anxiety disorders.

More information is available from the Netherlands Organisation for Scientific Research


Tuesday, 10 March 2009

Older men may father less intelligent kids

Children of older fathers perform less well in a range of cognitive tests during infancy and early childhood, a recent study has found.

Queensland Brain Institute researcher John McGrath analysed data about 33,437 children who were born between 1959 and 1965 in the United States.

Children were subject to cognitive testing at 8 months, 4 years and 7 years of age to measure the ability to think and reason, including concentration, learning, memory, speaking and reading skills.

The study found that the older the father, the more likely the child was to have lower scores on the various tests -– with the exception of one measure of physical coordination.

In contrast, the study found that children with older mothers gained higher scores in the same tests.

While previous researchers have suggested that older mothers may provide a more nurturing home environment, the Queensland Brain Institute study suggests that children of older fathers do not necessarily experience the same benefit.

McGrath and his colleagues hypothesise that the link between paternal age and a child's cognitive ability could be due to inferior sperm.

Unlike a woman's eggs, which are formed when she herself is in the womb, a man's sperm accumulates over his lifetime, which previous studies have suggested can mean increased incidence of mutations in the sperm at an older age.

More information is available from the research paper, which was published this week in PLoS Medicine.


Friday, 6 March 2009

Martian mountain could imply life

A study of the Martian volcano Olympus Mons has found that pockets of ancient water may still be trapped under the mountain.

Conducted by Rice University geophysicists Patrick McGovern and Julia Morgan, the study could help answer the question of whether the Red Planet ever had -- or still supports -- life.

Olympus Mons is about three times the height of Mount Everest and stands almost 15 miles high. It slopes gently for a distance of more than 150 miles from the foothills to the caldera.

The researchers modelled the formation of Olympus Mons with an algorithm known as particle dynamics simulation and determined that only the presence of ancient clay sediments could account for the volcano's asymmetric shape.

The presence of sediment indicates water was or is involved.

"What we were analyzing was the structure of Olympus Mons, why it's shaped the way it is," said McGovern, an adjunct assistant professor of Earth science and staff scientist at the NASA-affiliated Lunar and Planetary Institute.

"What we found has implications for life -- but implications are what go at the end of a paper," he noted.

Similar to volcanoes in Hawaii, Olympus is expected to have been able to grow to its size because of the clay's friction-reducing effect.

The researchers suspect that if they were able to stand on the northwest side of Olympus Mons and start digging, they'd eventually find clay sediment deposited there billions of years ago, before the mountain was even a molehill.

The researchers are interested in what may be trapped underneath the mountain, as there may still be fluids, and potentially life, embedded in the clay sediment.

"This deep reservoir, warmed by geothermal gradients and magmatic heat and protected from adverse surface conditions, would be a favored environment for the development and maintenance of thermophilic organisms," they wrote in a report that was published in February's issue of the journal Geology.

More information is available from Rice University's press release.