In Japan Reactor Failings, Danger Signs for the U.S.

TOKYO — Emergency vents that American officials have said would prevent devastating hydrogen explosions at nuclear plants in the United States were put to the test in Japan — and failed to work, according to experts and officials with the company that operates the crippled Fukushima Daiichi plant.

The failure of the vents calls into question the safety of similar nuclear power plants in the United States and Japan. After the venting failed at the Fukushima plant, the hydrogen gas fueled explosions that spewed radioactive materials into the atmosphere, reaching levels about 10 percent of estimated emissions at Chernobyl, according to Japan’s nuclear regulatory agency.

Venting was critical to relieving pressure that was building up inside several reactors after the March 11 tsunami knocked out the plant’s crucial cooling systems. Without flowing water to cool the reactors’ cores, they had begun to dangerously overheat.

American officials had said early on that reactors in the United States would be safe from such disasters because they were equipped with new, stronger venting systems. But Tokyo Electric Power Company, which runs the plant, now says that Fukushima Daiichi had installed the same vents years ago.

Government officials have also suggested that one of the primary causes of the explosions was a several-hour delay in a decision to use the vents, as Tokyo Electric managers agonized over whether to resort to emergency measures that would allow a substantial amount of radioactive materials to escape into the air.

But the release this week of company documents and interviews with experts provides the most comprehensive evidence yet that mechanical failures and design flaws in the venting system also contributed to delays. The documents paint a picture of increasing desperation at the plant in the early hours of the disaster, as workers who had finally gotten the go-ahead to vent realized that the system would not respond to their commands.

While venting would have allowed some radioactive materials to escape, analysts say that those releases would have been far smaller than those that followed the explosions at three of the plant’s reactors, which blew open containment buildings meant to serve as a first line of defense against catastrophe. The blasts may also have been responsible for breaches in containment vessels that have complicated efforts to cool the fuel rods and contain radioactive leaks from the site.

One reason the venting system at the plant, which was built by General Electric, did not work is that it relied on the same sources of electricity as the rest of the plant: backup generators that were in basements at the plant and vulnerable to tsunamis. But the earthquake may also have damaged the valves that are part of the venting system, preventing them from working even when operators tried to manually open them, Tokyo Electric officials said.

In either case, regulators in the United States and Japan will now need to determine if such systems at similar plants designed by G.E. need to undergo expensive and time-consuming retrofitting or redesign to allow them to function even in severe accidents.

“Japan is going to teach us lessons,” said David Lochbaum at the Union of Concerned Scientists. “If we’re in a situation where we can’t vent where we need to, we need to fix that.”

Officials from General Electric did not comment on Tuesday.

The seriousness of the crisis at the Fukushima plant became evident within hours of the quake and the tsunami that rushed over the plant’s sea wall.

Just 12 hours after the quake, the pressure inside Reactor No. 1 had reached roughly twice the maximum pressure the unit had been designed to withstand, raising fears that the vessels that house fuel rods would rupture, setting a possible meltdown in motion. With the pressure high, pumping in additional cooling water also was not possible.

Read full story at: http://nyti.ms/mNbeMt

Source: Nytimes.com

Can Batteries Replace Power Generators?

When the Long Island Power Authority said last summer that it was going to need new power capacity in the next few years, most people assumed that meant new generating stations or new transmission cables. But of the 16 companies that submitted proposals, one, AES Energy Storage, took an entirely different tack: it proposed batteries.

When all is said and done, batteries are not a source of energy; in fact, they consume it. For every 10 kilowatt-hours put into a battery, only about nine come back out. The battery is a little like a savings account at a bank, but with a negative interest rate. Still, withdrawals are possible at times when they are most useful.

Batteries are a temporary source of energy and power, with the instantaneous ability to meet load and do work. AES is proposing the use of a 400-megawatt battery, with the same output as a medium-size natural gas plant, that can operate for four hours. It would be about 10 times larger than the biggest grid-connected battery system now in service.

AES said the battery would also be a cleaner energy choice. That’s because the alternative would probably be new simple-cycle natural gas plants, which are relatively low in efficiency and have a high output of carbon dioxide and conventional pollutants per kilowatt-hour.

Batteries, on the other hand, could be charged at night using relatively cheap capacity from Long Island’s most efficient generators, combined cycle gas plants. Those use about 7,000 B.T.U.’s of energy per kilowatt-hour, compared with 10,000 or 11,000 for the simple-cycle plants.

Can a battery qualify if the utility wants power?

In fact, in the complicated world of the electric grid, batteries can do some jobs better than generation stations. One is providing a service called spinning reserve. At a power plant, that means spinning a turbine and burning fuel, but not actually making any energy, sitting in standby in case more power is suddenly needed. A battery can sit at the ready without actually spinning or using fuel.

Another is frequency regulation. Alternating current is supposed to change directions 60 times per second, but in reality is always just a little faster or a little slower than that. Plants that provide frequency regulation will add or subtract energy at precise intervals to keep the number of alternations near 60.

Power plants that do this work get extra wear and tear, and modern gas-fired turbines are not as good for that job as old-fashioned steam plants were. Batteries, though, can take up the slack.

John Zahurancik, vice president of operations and deployment at AES, pointed out that getting permission to build batteries is easier than getting the go-ahead to build more power plants. No new permits for air emissions or water consumption would be needed, for example, he said.

The Long Island Power Authority said it was just beginning to evaluate the responses to its request for proposals, which was issued last August. It has not said which submissions met its terms and will be evaluated, and whether proposals for energy storage can compete. Officials there also declined to say whether any of the other bids were submitted by storage companies.

AES already operates an 8-megawatt battery installation in Johnson City, N.Y., near Binghamton and a 12-megawatt system in Chile. It is building a 32-megawatt system in West Virginia adjacent to a 97-megawatt wind farm. Batteries paired with wind farms can smooth out the wind turbines’ highly variable output.

The company’s Long Island proposal is still in an early phase; AES has not, for example, chosen precisely what type of battery it would use.

Source: Nytimes.com

Tarantulas Shoot Silk from Their Feet

ScienceDaily (May 17, 2011) — Climbing is possibly one of the riskiest things an adult tarantula can do. Weighing in at anything up to 50g, the dry attachment systems that keep daintier spiders firmly anchored are on the verge of failure in these colossal arachnids.

"The animals are very delicate. They wouldn't survive a fall from any height," explains Claire Rind from the University of Newcastle, UK.

In 2006, Stanislav Gorb and his colleagues published a paper in Nature suggesting that tarantulas may save themselves from falling by releasing silk threads from their feet. However, this was quickly refuted by another group that could find no evidence of the silk. Fascinated by spiders and intrigued by the scientific controversy, Rind decided this was too good a challenge to pass up and discovered that tarantulas shoot silk from their feet when they lose their footing. She publishes her results in The Journal of Experimental Biology.

Teaming up with undergraduate Luke Birkett, Rind tested how well three ground-dwelling Chilean rose tarantulas kept their footing on a vertical surface. Gently placing one of the animals in a very clean aquarium with microscope slides on the floor, the duo cautiously upended the aquarium to see if the tarantula could hang on. "Given that people said tarantulas couldn't stay on a vertical surface, we didn't want to find that they were right," remembers Rind. But the spider didn't fall, so the duo gave the aquarium a gentle shake. The tarantula slipped slightly, but soon regained its footing. So the spider had held on against the odds, but would Rind find silk on the microscope slides?

Looking at the glass by eye, Rind couldn't see anything, but when she and Birkett looked closely under a microscope, they found minute threads of silk attached to the microscope slide where the spider had stood before slipping.

Next, Rind had to prove that the silk had come from the spiders' feet and not their web-spinning spinnerets. Filming the Chilean rose tarantulas as they were rotated vertically, Rind, Benjamin-James Duncan and Alexander Ranken disregarded any tests where other parts of the spiders' bodies contacted the glass and confirmed that the feet were the source of the silk. Also, the arachnids only produced their safety threads when they slipped.

But where on the spiders' feet was the silk coming from? Having collected all of the moulted exoskeletons from her Mexican flame knee tarantula, Fluffy, when she was young, Rind looked at them with a microscope and could see minute threads of silk protruding from microscopic hairs on Fluffy's feet. Next, the team took a closer look at moults from Fluffy, the Chilean rose tarantulas and Indian ornamental tarantulas with scanning electron microscopy and saw minute reinforced silk-producing spigots, which extended beyond the microscopic attachment hairs on the spiders' feet, widely distributed across the foot's surface. Rind also looked at the tarantula family tree, and found that all three species were only distantly related, so probably all tarantula feet produce the life-saving silk threads.

Finally, having noticed the distribution of the spigots, Rind realised that tarantulas could be the missing link between the first silk-producing spiders and modern web spinners. She explains that the spread of spigots on the tarantula's foot resembled the distribution of the silk spigots on the abdomen of the first silk spinner, the extinct Attercopus spider from 386 million years ago. The modern tarantula's spigots also looked more similar to mechanosensory hairs that are distributed over the spider's entire body, possibly making them an evolutionary intermediate in the development of silk spinning. So, not only has Fluffy settled a heated scientific debate but she also may be a link to the silk spinners of the past.

Source: Sciencedaily.com

There's No Magic Number for Saving Endangered Species

ScienceDaily (May 17, 2011) — A new study offers hope for species such as the Siberian Tiger that might be considered 'too rare to save', so long as conservation efforts can target key threats.

The findings have important implications for conserving some of the world's most charismatic endangered species, which often exist in populations far smaller than the many thousands of individuals that earlier studies had argued were necessary for viability.

Charismatic examples include the mountain gorilla, which likely now number 1,000 or less, the approximately 450 remaining Amur or Siberian tigers, the 180-500 remaining mature Philippine eagles, and the 70 wild Puerto Rican parrots.

The findings of a UK-US research team, the largest critical review of the use of minimum viable population (MVP) (*1) numbers in conservation, dispute the use of a universal MVP as a yardstick for conservation policies. According to the researchers there is no single population size that can be used as a catch-all guideline to save endangered species.

Co-author of the report, Dr. Philip Stephens, School of Biological and Biomedical Sciences, Durham University, said: "Populations usually show rapid declines as a result of human activities such as hunting and habitat conversion. The results of the study are encouraging and show that if we can remove the negative effects of human activities, even relatively small populations could be viable in the long term."

Dr. Greg Hayward, the U.S. Forest Service's (USFS) regional ecologist for Alaska said: "This is good news for biologists working to save species like the tiger. There's a lot of work to do to arrest the effects of poaching, prey loss and habitat destruction. However, if that work is successful, the tiger might yet be able to recover, despite the relatively small size of most tiger populations."

The study, published in the journal, Trends in Ecology and Evolution, shows that population sizes required for long-term viability vary, both within and among species, and depend on the specific circumstances in which the population is found. Estimates of viable population sizes were typically reduced to hundreds rather than thousands of individuals for populations that were relatively stable.

Previous studies have suggested that the allocation of conservation effort should be related to the number of individuals in threatened populations. For species which would require intense effort to raise numbers to 5,000 individuals, it might be too late to act and better to concentrate limited conservation resources elsewhere, the previous studies have suggested.

Researchers on the US-UK team argue that conservationists should not give up on saving an endangered species if its population is below an MVP figure, and they advise policy-makers to be cautious about setting guidelines for 'safe' population sizes.

The researchers also warn against potential complacency and stress the need to look in detail at the specific threats that a species faces. They argue that no population size is likely to be safe from extinction when conservation activities fail to reduce the impact of the factors causing the population to decline.

Dr. Curt Flather, a research ecologist with the USFS Rocky Mountain Research Station in Colorado said: "The enormous variability in estimates shows that many populations also need to be highly abundant to be viable. The extinction of the passenger pigeon, which numbered 3 to 5 billion individuals in North America during the 1800s, is a reminder that population size alone is no guarantee against extinction."

Read more at http://www.sciencedaily.com/releases/2011/05/110516201101.htm

Source: Sciencedaily.com

HIV Drug Could Prevent Cervical Cancer, Researchers Discover

ScienceDaily - A widely used HIV drug could be used to prevent cervical cancer caused by infection with the human papilloma virus (HPV), say scientists.

University of Manchester researchers, working with colleagues in Canada, have discovered how the antiviral drug lopinavir attacks HPV by switching on a natural viral defence system in infected cells.

The study, published in the journal Antiviral Therapy, builds on the team's previous work in 2006 that first identified lopinavir as a potential therapeutic for HPV-related cervical cancer following laboratory tests on cell cultures.

"Since publishing our earlier work, we have now found that lopinavir selectively kills HPV-infected, non-cancerous cells, while leaving healthy cells relatively unaffected," said Dr Ian Hampson, from Manchester's School of Cancer and Enabling Sciences.

"This is a very significant finding as these cells are not cancer cells but are the closest thing to being like the cells found in a pre-cancerous HPV infection of the cervix. In addition we were also able to show that lopinavir kills these HPV-infected cells by re-activating a well-known antiviral system that is suppressed by HPV."

In many developing countries, HPV-related cervical cancer is still one of the most common women's cancers accounting for approximately 290,000 deaths per year worldwide. The same virus also causes a significant proportion of cancers of the mouth and throat in both men and women and this disease is showing an alarming increase in developed countries, such as the UK, where it is now more than twice as common as cervical cancer.

Although in the developed world vaccination programmes against HPV are well underway, these are not effective in women already infected with HPV. Furthermore, the current vaccines do not protect against all types of HPV and they are expensive, which will limit their use in countries with limited resources. A cheap and preferably self-administered treatment that could eliminate early-stage HPV infections before these have developed into cancers would therefore have distinct health advantages.

Dr Hampson said: "Our results suggest that for this drug to work against HPV it would be necessary to treat virus-infected cells of the cervix with roughly 10-15 times the concentration that is normally found in HIV-infected patients taking lopinavir as tablets. This implies that, for this treatment to work, it would need to be locally applied as a cream or pessary."

Co-author on the paper, Dr Lynne Hampson, added: "These results are very exciting since they show that the drug not only preferentially kills HPV-infected non-cancerous cells by re-activating known antiviral defence systems, it is also much less toxic to normal non-HPV infected cells.

"Lopinavir is obviously safe for people to take as tablets or liquid but our latest findings provide very strong evidence to support a clinical trial using topical application of this drug to treat HPV infections of the cervix."

The research in Manchester was carried out by the Hampsons' PhD student, Gavin Batman, who was funded by the Humane Research Trust charity, with additional funding supplied by the Caring Cancer Trust and the Cancer Prevention Research Trust.

Source: Sciencedaily.com

Protein Active in Small Part of Brain Contributes to Obesity, Researchers Discover

ScienceDaily - Weizmann Institute scientists have added another piece to the obesity puzzle, showing how and why a certain protein that is active in a small part of the brain contributes to weight gain.

This research appears in Cell Metabolism.

Prof. Ari Elson and his team in the Institute's Molecular Genetics Department made the discovery when working with female mice that were genetically engineered to lack this protein, called protein tyrosine phosphatase epsilon (PTPe, for short). The scientists had originally intended to investigate osteoporosis, and thus, they also removed the ovaries of these mice. Taking out ovaries typically causes mice to gain weight to the point of obesity -- so the scientists were surprised to find that the weight of the genetically-engineered mice remained stable. Working with Dr. Alon Chen and his group in the Neurobiology Department and Prof. Hilla Knobler, Head of the Unit of Metabolic Disease and Diabetes of Kaplan Medical Center, the researchers fed these mice a high-fat diet, yet the PTPe-deficient mice maintained their svelte figures; they burned more energy and had more stable glucose levels as well.

To find out how the lack of this protein could keep mice slim and healthy, the scientists looked at the hypothalamus, a region of the brain that takes in assorted stimuli, including a wide variety of hormones, and sends out messages of its own in the form of new hormones and nerve signals. The hypothalamus plays a vital role in regulating body mass -- a complex balancing act that involves, among other things, controlling appetite and physical activity.

Elson and his team found that PTPe blocks the messages from a hormone called leptin -- a key player in body mass regulation. They revealed exactly how it does this: PTPe responds to the leptin signal in the hypothalamus, inhibiting certain molecules, which in turn dampens that signal.

Among its actions, leptin reduces appetite and increases physical activity. Paradoxically, obese people often have a surfeit of leptin circulating in their blood. This is because, while their bodies produce the hormone normally, their cells become resistant to its effects, and more leptin is then generated to compensate.

The new research shows that PTPe plays a role in this resistance. The scientists found that the mice lacking the protein were highly sensitive to leptin; and they remained so despite aging, ovary removal or high-fat diets. This suggests that in obese humans with leptin insensitivity, inhibiting PTPe might, conceivably, help to reestablish the leptin response and help induce weight loss. This, however, requires further research to ensure that it acts in the same way in humans with no dangerous side-effects.

Elson: "Interestingly enough, the effect seems to be gender-specific. Male mice hardly benefitted at all from the lack of PTPe compared with the female mice. This finding could open up whole new lines of inquiry in obesity studies."

Prof. Ari Elson's research is supported by the M.D. Moross Institute for Cancer Research; the Kekst Family Institute for Medical Genetics; the Yeda-Sela Center for Basic Research; the Fritz Thyssen Stiftung; the Maurice and Vivienne Wohl Charitable Foundation; and the estate of Fannie Sherr. Prof. Elson heads the Ekard Research School of Biological Science; and the Lorry I. Lokey Research School of Biochemical Science. He is the incumbent of the Marshall and Renette Ezralow Professorial Chair.

Dr. Alon Chen's research is supported by the Nella and Leon Benoziyo Center for Neurosciences; the Nella and Leon Benoziyo Center for Neurological Diseases; the Carl and Micaela Einhorn-Dominic Brain Research Institute; the Irwin Green Alzheimer's Research Fund; the Mark Besen and the Pratt Foundation, Australia; Roberto and Renata Ruhman, Brazil; and Martine Turcotte, Canada. Dr. Chen is the incumbent of the Philip Harris and Gerald Ronson Career Development Chair.

Source: Sciencedaily.com

Keeping Oysters, Clams and Mussels Safe to Eat

ScienceDaily (Apr. 19, 2011) — Eating raw or undercooked mollusks may pose a safety hazard if they are harvested from waters polluted with pathogenic microbes, so U.S. Department of Agriculture (USDA) scientists are studying ways to enhance the food safety of these popular shellfish.

For example, USDA molecular biologist David H. Kingsley at Delaware State University in Dover is exploring new techniques that will decontaminate mollusks while protecting the seafood's flavor, texture, and color.

Kingsley, with USDA's Agricultural Research Service (ARS), is investigating the use of a specialized commercial procedure known as high pressure processing, or HPP, to inactivate viruses. HPP is already used commercially to pasteurize some juices and meats, and by some shellfish processors to deactivate Vibrio bacteria. But Kingsley and colleagues are the first to show that HPP also can inactivate some foodborne viruses.

HPP equipment compresses water to create intense pressures as high as 90,000 pounds per square inch. Normal atmospheric pressure is about 15 pounds per square inch at sea level.

In tests targeting hepatitis A virus, the cause of a contagious liver disease, the team showed that an HPP treatment of 60,000 pounds per square inch of pressure for five minutes inactivated 99.9 percent of the virus in oysters that had been exposed to the pathogen in laboratory tanks.

The hepatitis A studies led to a collaboration with researchers in Italy, where raw or lightly cooked Mediterranean mussels, popular in European markets, are sometimes a vector for the virus. The ARS scientists and colleagues from Italy's University of Bari found that the 5-minute, HPP treatment inactivated 99.9 percent of the virus in North American blue mussels and in Mediterranean mussels.

HPP is not perfect. For instance, the pressure needed to inactivate hepatitis A virus may alter the taste and texture somewhat. Additional research may reveal ways to mitigate these changes.

Kingsley and his co-investigators have published these and other findings in Food and Environmental Virology, Virus Research and other scientific journals. The Dover team is part of the ARS Eastern Regional Research Center in Wyndmoor, Pa.

Source: Sciencedaily.com