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Scientists copy nature to split water into hydrogen and oxygen

Mon, 18 Aug 2008 07:25:00 -0400

An international team of researchers has used chemicals found in plants to replicate a key process in photosynthesis, paving the way to a new approach that uses sunlight to split water into hydrogen and oxygen.

The breakthrough, led by Monash University in Australia, could revolutionize the renewable energy industry by making hydrogen – touted as the clean, green fuel of the future – cheaper and easier to produce on a commercial scale.

It came about after Professor Leone Spiccia, Robin Brimblecombe and Dr Annette Koo from Monash University teamed with Dr Gerhard Swiegers at the CSIRO and Professor Charles Dismukes at Princeton University to develop a system comprising a coating that can be impregnated with a form of manganese, a chemical essential to sustaining photosynthesis in plant life.

“We have copied nature, taking the elements and mechanisms found in plant life that have evolved over 3 billion years and recreated one of those processes in the laboratory,” Professor Spiccia said.

According to Professor Spiccia, a manganese cluster is central to a plant’s ability to use water, carbon dioxide and sunlight to make carbohydrates and oxygen.

Professor Charles Dismukes developed man-made mimics of this cluster some time ago, and the research team took it a step further, harnessing the ability of these molecules to convert water into its component elements, oxygen and hydrogen.

“The breakthrough came when we coated a proton conductor, called Nafion, onto an anode to form a polymer membrane just a few micrometres thick, which acts as a host for the manganese clusters,” said Spiccia.

“Normally insoluble in water, when we bound the catalyst within the pores of the Nafion membrane, it was stabilised against decomposition and, importantly, water could reach the catalyst where it was oxidized on exposure to light,” he added.

This process of “oxidizing” water generates protons and electrons, which can be converted into hydrogen gas instead of carbohydrates as in plants.

“Whilst man has been able to split water into hydrogen and oxygen for years, we have been able to do the same thing for the first time using just sunlight, an electrical potential of 1.2 volts and the very chemical that nature has selected for this purpose,” Spiccia said.

Testing revealed the catalyst assembly was still active after three days of continuous use, producing oxygen and hydrogen gas in the presence of water, an electrical potential and visible light.

According to Spiccia, the efficiency of the system needed to be improved, but this breakthrough had huge potential.

“We need to continue to learn from nature so that we can better master this process,” he said.

“The production of hydrogen using nothing but water and sunlight offers the possibility of an abundant, renewable, green source of energy for the future for communities across the world,” he added. (ANI)

Mini drug-producing biofactories built in yeast

Mon, 18 Aug 2008 07:22:00 -0400

California Institute of Technology scientists in the U.S. say that mini biofactories in yeast may be useful for churning out large quantities of drugs, including antiplaque toothpaste additives, antibiotics, nicotine, and even morphine.

Christina D. Smolke, an assistant professor of Chemical Engineering, has revealed that she and graduate student Kristy Hawkins have genetically modified common baker''s yeast (Saccharomyces cerevisiae) so that it contains the genes for several plant enzymes.

The researchers say that the enzymes enable the yeast to produce a chemical called reticuline, which is a precursor for many different classes of benzylisoquinoline alkaloid (BIA) molecules—a large group of chemically intricate compounds, such as morphine, nicotine, and codeine, which are naturally produced by plants.

BIA molecules exhibit a wide variety of pharmacological activities like antispasmodic effects, pain relief, and hair growth acceleration. Other BIAs have shown anticancer, antioxidant, antimalarial, and anti-HIV potential.

"There are estimated to be thousands of members in the BIA family, and having a source for obtaining large quantities of specific BIA molecules is critical to gaining access to the diverse functional activities provided by these molecules," says Smolke, whose lab focuses on using biology as a technology for the synthesis of new chemicals, materials, and products.

However, the natural plant sources of BIAs accumulate only a small number of the molecules, usually "end products" like morphine and codeine that, while valuable, cannot be turned into other compounds, thus limiting the availability of useful new products.

Smolke and Hawkins added the genes for other enzymes, from both plants and humans, to their reticuline-producing yeast.

This allowed the yeast to efficiently generate large quantities of the precursors for sanguinarine, a toothpaste additive with antiplaque properties; berberine, an antibiotic; and morphine.

The researchers are now trying to engineer the yeast so that they will turn these precursor molecules into the final, pharmacologically useful molecules.

"But even the intermediate molecules that we are producing can exhibit important and valuable activities, and a related area of research will be to examine more closely the pharmacological activities of these metabolites and derivatives now that pure sources can be obtained," says Smolke, who estimates that her system could be used for the large-scale manufacture of BIA compounds in one to three years.

The researchers are also planning to extend their research to the production of BIAs that do not normally exist in nature.

"If one thinks of these molecules as encoding functions that are of interest to us, the ability to produce nonnatural alkaloids will provide access to more diverse functions and activities. By expanding to nonnatural alkaloids, we can search for molecules that provide enhanced activities, new activities, and not be limited by the activities that have been selected for in nature," says Smolke.

"Our work has the potential to result in new therapeutic drugs for a broad range of diseases. This work also provides an exciting example of the increased complexity with which we are engineering biological systems to address global societal challenges," she says. (ANI)

Wind screens could save glaciers from melting

Mon, 18 Aug 2008 07:22:00 -0400

A German geographer has said that wind screens could help to keep chilly breezes on top of glaciers in Europe, thus saving them from melting.

The glaciers of the world are melting fast, and the ice-rivers of Europe’s Alps are no exception. Some researchers think that within 30 years Europe’s glaciers will all but vanish.

With the world’s temperature rising, there seem to be few ways to save the glaciers. Even if the world’s carbon emissions were dramatically reduced in the near future, the fate of the glaciers seems sealed.

So far, only one method has proven effective in slowing glacial melt: massive, light colored covers that keep the glaciers cool by reflecting sunlight.

But they’re usually only enough to preserve a few ski slopes.

Now, according to a report in Spiegel Online, geographer Hans-Joachim Fuchs in the western German city Mainz has come with an idea to save the glaciers.

The researcher wants to harness the power of cold mountain winds - so-called kabatic winds, or streams of cold, dense air that flow downhill - with windscreens, which would keep the cool air on top of the glaciers, perhaps preserving them for a little while longer.

To demonstrate this idea, Fuchs and 27 students have headed to the Rhone glacier in Switzerland to install a windscreen measuring 15 meters long (50 feet) and 3 meters high at an elevation of 2,300 meters (7,545 feet) on the leading edge of the glacier.

The team will be measuring the effectiveness of the screen to see if it’s a viable solution.

Fuchs has described his project as a “little test.” “If all goes well, then we’ll go ahead with something much larger,” he said. (ANI)

One of two mummified fetuses may be Tutankhamun’s daughter, says scientist

Mon, 18 Aug 2008 07:21:00 -0400

A scientist has said that the ongoing analysis on the mummified remains of two female fetuses buried in the tomb of Tutankhamun will most likely show that at least one of the stillborn children is the offspring of the teenage Egyptian pharaoh.

The scientist in question is Robert Connolly, senior lecturer in physical anthropology from the University of Liverpool’s Department of Human Anatomy and Cell Biology, who has carried serological analysis on the mummified remains of the two fetuses.

“I studied one of the mummies, the larger one, back in 1979 (and) determined the blood group data from this baby mummy and compared it with my 1969 blood grouping of Tutankhamun,” said Connolly.

“The results confirmed that this larger fetus could indeed be the daughter of Tutankhamen,” he added.

The fetuses have been stored at the Cairo University’s Faculty of Medicine since archaeologist Howard Carter first discovered them in Tutankhamun''s tomb on the west bank of Luxor, Egypt in 1922.

Egyptologists have long debated whether these mummies were the stillborn children of King Tut and his wife Ankhesenamun or if they were placed in the tomb with the symbolic purpose of allowing the boy king to live as newborns in the afterlife.

Never publicly displayed, the two fetuses will soon undergo CT scans and DNA testing to determine possible diseases and their relation to the famous pharaoh, and possibly “identify the fetuses’ mother,” Zahi Hawass, the head of Egypt’s Supreme Council of Antiquities, said in a statement.

“This is a very important project, as these fetuses have never been fully studied,” Swiss anatomist and paleopathologist Frank Ruhli told Discovery News.

The smaller fetus, about five months in gestational age, has only been examined by Carter in 1925. The mummy is less than 30 centimeters (11.8 inches) in height and is well preserved, according to Ruhli.

The older, larger fetus is estimated to be between seven and nine months in gestational age. It is less well preserved than the other and measures 38.5 centimeters (15.16 inches).

According to Hawass, DNA tests might help solve the riddle of the mummies and even more mysteries around King Tut.

“The fetuses might help identify the lineage and the family of King Tutankhamun, particularly his parents,” he said.

“Since these two fetuses were found in the tomb of Tutankhamen, there is no reason to think that they were other than his offspring, a matter supported by my 1979 blood group studies,” said Connolly.

The two fetuses will be studied at a new ancient DNA lab opening at Cairo University to supplement research at a similar lab created at the Egyptian Museum, with funding from the Discovery Channel.

The DNA tests and CT scans should be finished by December. (ANI)

Amplifying cell death signals causes pre-cancerous cells to self-destruct

Mon, 18 Aug 2008 07:20:00 -0400

Rockefeller University scientists say that they have devised a way to amplify death signals that make a cell multiplying in a dangerously abnormal way to kill itself before becoming cancerous.

The researchers say that the trick is to inactivate a protein that normally helps cells to avoid self-destruction.

Lead researcher Hermann Steller, Strang Professor and head of the Laboratory of Apoptosis and Cancer Biology, claims that this is the first study to reveal the mechanism whereby a class of proteins called IAPs (inhibitor of apoptosis proteins) regulates cell death.

A research article in the journal ‘Genes and Development’ says that by exposing the mechanism in mice, the finding also marks a breakthrough in the field, and opens the door for developing a new class of drugs that may aid in cancer therapy and prevention.

“In a way, these mice are guiding clinical trials. We now can study how IAPs contribute to the development of cancer in a living animal and develop drugs to prevent or thwart the disease,” says Steller, who is also a Howard Hughes Medical Institute investigator.

IAP inhibiting apoptosis (programmed cell death) to keep cells alive by directly binding to executioner enzymes called caspases. However, so far, precisely how IAPs save cells from death has remained unclear.

With graduate student Andrew Schile and postdoc Maria Garcia-Fernandez, Steller studied the X-linked inhibitor of apoptosis protein (XIAP), and the role of its largely ignored RING domain, which has been implicated in promoting cell death as well as survival.

They found that genetically targeting and removing RING affected only some cell types in healthy mice.

Even though the mice without the RING had more cell death than the mice with the RING, according to the researchers, both lived normal lives under normal laboratory conditions.

Comparing mice that were genetically predisposed to developing cancer, the research group found that the animals without the RING lived twice as long as those with it.

“Cancer cells thrive by disabling the molecular machinery that tells sick cells to die. By removing the RING, we wanted to see whether we would trick the machinery to turn back on. And that’s what happened. Cells die more readily, making it much more difficult for cancer to be established,” says Steller.

He and his colleagues specifically showed that the RING transfers molecular tags on caspases that label these enzymes for destruction.

According to him, the more tags, the stronger the signal to save the cell from death.

However, when the RING was removed, fewer molecular tags were transferred to caspases, and, often, the signal to save the cell from death was not strong enough. Thus, more cells died.

The researchers insist that more research is needed to identify the IAP genes that are important in the development of cancer.

“We need to use genetics to sort out which individual IAPs contribute to tumors and which IAPS we need to target in order to cure cancer. This was a very big step in understanding what role IAPs play in cancer, but it isn’t the last,” says Steller. (ANI)

U.S. physicist develops ‘electrifying’ theory

Mon, 18 Aug 2008 07:18:00 -0400

A theory that may help build future superconducting alternating-current fault-current limiters for electricity transmission and distribution systems has been developed, thanks to the efforts of a physicist at the U.S. Department of Energy’s Ames Laboratory.

John R. Clem says that he has basically identified design strategies that can reduce costs and improve efficiency in a bifilar fault-current limiter, a new and promising type of superconducting fault-current limiter.

Just like household surge protectors that save equipment like televisions and computers from damage during a lightning strike, fault-current limiters protect power grids from sudden spikes in power.

During the study, Clem analysed a type of fault-current limiter, called a bifilar fault-current limiter, developed by Siemens and American Superconductor Corporation.

“I was able to theoretically confirm that planned design changes to the current bifilar fault-current limiter being developed by Siemens and American Superconductor would decrease AC losses in the system. My calculations are good news for the future of the device,” he said.

“I modelled the bifilar design as an infinite stack of superconducting tapes, in which adjacent tapes carry current in opposite directions. I was able to find an exact solution for the magnetic fields and currents that are generated in such a stack of tapes. Once I calculated how the magnetic flux penetrates into the tape, I then could calculate how much energy is lost in each current cycle for different tape widths and spacings between adjacent tapes,” the researcher added.

A research article describing this work has been published in a recent issue of Physical Review B. (ANI)

''Virtual archaeologist'' to shed new light on 3,500 yr old civilization

Mon, 18 Aug 2008 07:17:00 -0400

A research team, from Princeton University in the US, has developed an automated system that works like a ''virtual archaeologist'' to shed new light on Thera, an island civilization near Greece that was buried under volcanic ash more than 3,500 years ago.

For several decades, archaeologists in Greece have been painstakingly attempting to reconstruct wall paintings that hold valuable clues to the ancient culture of Thera.

Now, thanks to an automated system developed by a team of Princeton University computer scientists working in collaboration with archaeologists in Greece, this Herculean task may soon get much easier.

According to David Dobkin, the Phillip Y. Goldman ''86 Professor in Computer Science and dean of the faculty at Princeton, the new technology "has the potential to change the way people do archaeology."

"This approach really brings in the computer as a research partner to archaeologists," said Dobkin, who got the inspiration for the project after a 2006 visit to the archaeological site of Akrotiri on the island of Thera, which in present-day Greece is known as Santorini.

To design their system, the Princeton team collaborated closely with the archaeologists and conservators working at Akrotiri, which flourished in the Late Bronze Age, around 1630 B.C.E.

The Princeton system uses inexpensive, off-the-shelf hardware and is designed to be operated by archaeologists and conservators rather than computer scientists.

The system employs a combination of powerful computer algorithms and a processing system that mirrors the procedures traditionally followed by archaeologists.

"We mimic the archaeologists'' methods as much as possible, so that they can really use our system as a tool," said Szymon Rusinkiewicz, an associate professor of computer science whose research team led the Princeton effort.

"When fully developed, this system could reduce the time needed to reconstruct a wall from years to months. It could free up archaeologists for other valuable tasks such as restoration and ethnographic study," he added.

In 2007, a large team of Princeton researchers made a series of trips to Akrotiri, initially to observe and learn from the highly skilled conservators at the site, and later to test their system.

During a three-day visit to the island in September 2007, they successfully measured 150 fragments using their automated system.

Although the system is still being perfected, it already has yielded promising results on real-world examples.

For instance, when tested on a subset of fragments from a large Akrotiri wall painting, it found 10 out of 12 known matches. Further, it found two additional matches that were previously unknown.

"This showed that the system could work in a real-life situation," said Tim Weyrich, a postdoctoral teaching fellow in computer science at Princeton.

To make the system run faster, the researchers are planning to incorporate a number of additional cues that archaeologists typically use to simplify their searching for matching fragments. (ANI)

Study casts light on the psychology behind pupils who don’t cheat

Mon, 18 Aug 2008 07:16:00 -0400

Students who score high on measures of courage, empathy and honesty are less likely than others to have cheated in the past, and to intend to cheat in the future, according to a study at one Ohio university.

Most of the students who reported less cheating during the study were also found to believe that their fellow pupils did not commit academic dishonesty regularly.

Sara Staats, co-author of the research and professor of psychology at Ohio State University’s Newark campus, said that students who did not cheat had a more positive view of others.

“They don’t see as much difference between themselves and others,” Staats said.

The researchers also revealed that pupils who scored lower on courage, empathy and honesty, and were more likely to report that they have cheated, saw other students as cheating much more often than they did, rationalizing their own behaviour.

Staats said the continuing research project she has undertaken with Assistant Professor Julie Hupp and undergraduate Psychology student Heidi Wallace, both at Ohio State-Newark, aimed to find out more about the students who did not cheat—a group her team called “academic heroes”.

“Students who don’t cheat seem to be in the minority, and have plenty of opportunities to see their peers cheat and receive the rewards with little risk of punishment. We see avoiding cheating as a form of everyday heroism in an academic setting,” she said while presenting her findings in Boston at two poster sessions at the annual meeting of the American Psychological Association.

The research also suggested that the academic heroes would feel more guilt if they cheated compared to non-heroes.

“The heroes didn’t rationalize cheating the way others did, they didn’t come up with excuses and say it was OK because lots of other students were doing it,” Staats said.

The researchers say that one reason to study cheating at colleges and universities is to try to figure out ways to reduce academic dishonesty.

They conceded that more work needs to be done to identify the best ways to prevent cheating, but insist that the present research, with its focus on positive psychology, suggests one avenue.

“We need to do more to recognize integrity among our students, and find ways to tap into the bravery, honest and empathy that was found in the academic heroes in our study,” Staats said. (ANI)