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Gecko-inspired multifocal contact lenses, cameras on the anvil

May 8, 2009 By admin Leave a Comment

Washington, May 8 (ANI): Scientists are all set to harness the mechanism behind nocturnal geckos’ unique ability to see colours at night, in making multifocal contact lenses and better cameras.

Researchers at Lund University in Sweden have found that the key to the exceptional night vision of the nocturnal helmet gecko is a series of distinct concentric zones of different refractive powers.
The multifocal optical system in geckos is comprised of large cones, which was calculated to be over 350 times more sensitive than human cone vision at the human colour vision threshold.

“We were interested in the geckos because they – and other lizards – differ from most other vertebrates in having only cones in their retina.With the knowledge from the gecko eyes we might be able to develop more effective cameras and maybe even useful multifocal contact lenses,” said project leader Dr. Lina Roth, from the Department of Cell and Organism Biology at the university.

The nocturnal geckos’ multifocal optical system gives them an advantage because light of different ranges of wavelengths can focus simultaneously on the retina.

Another possible advantage of their optical structure is that their eyes allow them to focus on objects at different distances, which makes their multifocal eye to generate a sharp image for at least two different depths.

Roth said that geckos that are active during the day do not possess the distinct concentric zones and are considered monofocal.

The scientists also developed a new method to gather optical data from live animals without any harm to their modifications to the Hartmann-Shack wavefront sensor.

“Studies of animals with relatively large eyes, such as owls and cats, have included surgery and fixation of the head. In this study, we demonstrate that it is possible to obtain high-resolution wavefront measurements of small, unharmed gecko eyes without completely controlling the gaze or the accommodation of the animal eyes,” said the authors.

The study has been published online in the Journal of Vision. (ANI)

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Vehicular pollutants stick to the lung more than other smoke, dust particles

April 2, 2009 By admin Leave a Comment

London, April 2 (ANI): In what may lead to a change in the way air pollution is evaluated, scientists at Lund University in Sweden have shown that the tiny particles from traffic fumes are far “stickier” than other smoke and dust particles.

Research leader Jakob Londahl came to this conclusion after measuring how many airborne particles stay behind in the lungs.

For that purpose, the researchers used a new device called RESPI, which brings air being inhaled in through one chamber, and exhaled air out through a second chamber.

The device helped the researchers analyse particle number and size in both chambers.

Londahl asked nine healthy adults to breathe into the RESPI device while standing on the kerbside of a six-lane Copenhagen boulevard, which sees around 65,000 vehicles pass by on a typical weekday.

“We found most traffic fume particles to be very small and hydrophobic (having little affinity for water), meaning they did not grow bigger once inside the wet lung. But small particles get deposited in the lung more easily,” New Scientist magazine quoted the researcher as saying.

Having noted the street measurements, the researchers compared them with the deposition of particles inhaled from an open fire and a biomass burner, which was measured in a previous study.

The team observed that for each microgram of particles inhaled, 16 times as many of the tiny traffic particles got retained in the lung than either the larger soot particles from wood smoke or the moisture-sensitive salts from the biomass burner that clump into bigger particles once inside the lung.

According to them, the traffic deposits also had three times the surface area of those inhaled in the biomass combustion study.

“There is some debate as to what characteristics of particles make them unhealthy – if it is mass or surface area or number. Our results support that it is the latter two, but at the moment, most air quality policies limit amounts by mass,” says Londahl.

The researchers next plan to study how the deposition of traffic exhaust particles differs between healthy people and those with respiratory diseases.

A research article on this study has been published in the journal Environmental Science and Technology. (ANI)

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Permafrost likely to shrink in northern Sweden

February 22, 2009 By admin Leave a Comment

Washington, Feb 21 (ANI): A new study by researchers from Lund University in Sweden has determined that permafrost is thawing in northern Sweden, because of warmer summers and more winter precipitation.

According to a report in ENN (Environmental News Network), the study was undertaken by physical geographer Margareta Johansson at Lund University, who studied lowland permafrost in peat mires surrounding Abisko.

Permafrost is ground that is frozen year round at least two years in a row. North of the Arctic Circle permafrost is common due to the cold climate.

Johansson said that permafrost is being affected by climate changes.

“At one of our sites, permafrost has completely disappeared from the greater part of the mire during the last decade,” she said.

In areas where permafrost is thawing, the ground becomes unstable and can collapse. This can be a local and regional problem in areas with cities and infrastructure.

Moreover, the thaw can cause increased emissions of the greenhouse gases carbon dioxide and methane from the ground.

Roughly 25 percent of all land surface in the northern hemisphere are underlain by permafrost.

The thawing of permafrost that occurs today is likely to continue, in Johansson’s view.

She regards it as probable that there will be no permafrost in lowland areas around Abisko in 50 years.

“With the present climate it is likely that the changes seen in permafrost in the Abisko area will also occur in other areas, and my study can therefore provide a basis for studies in other geographic areas that are next in line,” she said.

Johansson’s research shows that the permafrost in the Abisko area is thawing both from above and from below.

From above, it is thawing primarily because the summers have become warmer and because the snow cover has become thicker in winter.

A thicker snow layer acts as an insulating blanket, which means that the ground does not get as cold as it would under a thinner layer of snow.

From below, the permafrost is thawing probably as a result of greater mobility in the groundwater.

According to Johansson, the annual precipitation of both rain and snow has increased dramatically during the last decade.

More rain and more melted snow create more movement down in the groundwater, which thaws the permafrost. (ANI)

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Potential new weapon against HIV identified

January 14, 2009 By Rajesh Leave a Comment

Washington, Jan 13 (ANI): An international team of researchers has identified a potentially new weapon in battle against HIV infection – blood types.

Researchers from Canadian Blood Services, The Hospital for Sick Children (SickKids) and Lund University in Sweden have discovered that certain blood types are more predisposed to contracting HIV, while others are more effective at fending it off.

A carbohydrate-containing antigen, termed Pk blood group which is distinct from the well-known ABO and Rh blood grouping systems, is present at variable levels on the surface of white and red blood cells in the general population.

Their study shows that cells from rare individuals ( 1 in a million) who produce excess of this blood group antigen have dramatically reduced sensitivity to HIV infection.

Conversely, another slightly more common subgroup of people who do not produce any Pk ( 5 in a million) was found to be much more susceptible to the virus.

“This study is not suggesting that your blood type alone determines if you will get HIV. However, it does suggest that individuals who are exposed to the virus, may be helped or hindered by their blood status in fighting the infection,” said lead author Dr. Don Branch of Canadian Blood Services.

Increasing the level of the Pk antigen in cells in the laboratory also resulted in heightened resistance to HIV, while lowering it increased susceptibility.

“This discovery implicates the Pk level as a new risk factor for HIV infection and demonstrates the importance of blood-group-related science,” said Dr. Olsson.

The study is published in Blood, which is currently available online. (ANI)

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Gecko-inspired multifocal contact lenses, cameras on the anvil

Vehicular pollutants stick to the lung more than other smoke, dust particles

Permafrost likely to shrink in northern Sweden

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