The existence of living nanoparticles - or more controversially, nanobacteria - is a hotly debated topic in scientific circles. Isolating a genetic signature - which would indicate that the entities were indeed alive - has proven problematic, and what would appear to be successful laboratory culturing of the entities has in the past been discounted as simple crystal growth. Now, however, Mayo Clinic researchers believe they have isolated genetic material from the entities and in this case linked them with the formation of kidney stones.

Kidney stones are associated with calcification, the process in which organs and blood vessels become clogged with calcium deposits. What causes calcium deposits to build up is something of a mystery. Other studies have linked calcification to the presence of nanosized particles which some scientists believe could play a role in the development of kidney stones.

"We are looking at how kidney stones start as very small calcifications inside the kidney and then eventually grow into stones," said Mayo Clinic's John Lieske. "In the laboratory, we have isolated nanoparticles from kidney tissue and kidney stones, and have successfully propagated them in culture. This does not clearly confirm the role of nanoparticles in the formation of kidney stones, but it offers insight not otherwise known."

It's theorized that if nanoparticles become localized in the kidney, they can become the focus of subsequent growth into larger stones over months to years. Other factors, such as physical chemistry and protein inhibitors of crystal growth, also play a role. But what scientists don't quite understand is why, where and how they start growing.

Frustratingly, the presence of proteins, RNA and DNA does not prove that nanoparticles are viable living forms because a genetic signature has not been identified, explains Lieske. A genetic signature would prove beyond doubt that nanoparticles are indeed living forms that replicate and can cause disease.

Intriguingly, the study cites evidence that the calcification process is not driven solely by physical chemistry, but instead is influenced by specific proteins and cellular responses. "There are at least two novel hypotheses here in terms of how stones might actually form. One: an infectious agent. If that was the case, that would point us in the direction of using different kinds of treatments specific to an infectious agent. Two: the idea that cells drive calcification. That would suggest other alternative therapies," added co-researcher Virginia Miller.

Another study by the Mayo Clinic researchers in the same journal documents attempts to identify a DNA chemical marker in nanoparticles. The preliminary study suggests that nanoparticles from human samples share spectroscopic characteristics with calcified bacteria that exist in freshwater lakes. However, studies could not confirm whether the nanoparticles are calcified bacteria or hydroxyapatite crystals that precipitated upon proteins present in the culture medium used to replicate the nanoparticles. Researchers did, however, identify chemical bonds between proteins and calcium in nanoparticles that were similar to those found in the bacteria that calcified in the environment. "Right now the results are inconclusive. In some of the segments we saw a characteristic signal that might suggest DNA, but in others we did not," Miller said.

Miller added that the tools and processes used in nanoparticle research have yet to be perfected. "We are still in the learning process of how to handle the material. It was disappointing that we did not find any consistent DNA information. We think the findings were inconclusive, in part, because of the inability to apply these techniques in conditions suitable to nanoparticles," she concluded.

In a paper appearing this week in the advance online edition of Nature Neuroscience, UC Berkeley researchers report conclusive evidence from these experiments that humans do indeed gain a performance advantage from cross-nostril comparisons. They also found that humans can scent-track, and that, with training, they can improve their accuracy significantly while nearly doubling their speed along the scent trail.

In one experiment, the authors found that while volunteers with one nostril blocked could still track a scent - in this experiment, essence of chocolate - volunteers with two open nostrils tracked a scent quicker and with fewer deviations from the trail. "We were asking the question, 'Are two nostrils better than one"'" said lead author Jess Porter, a graduate student in biophysics at UC Berkeley. "The answer is yes."

Apparently, according to Porter and her colleagues, the mammalian brain compares smells between nostrils to tell where an odor is coming from in the same way that the brain compares the sounds entering a person's two ears to locate a source. Until now, many researchers thought this was unlikely because a mammal's nostrils, in a mouse, for example, are too close together to receive distinctly different smells.

"The human brain compares information from two 'noses' to turn smell information into spatial information," said Noam Sobel, associate professor of neuroscience and psychology and member of the program in biophysics at UC Berkeley.

Sobel hopes to use information from these experiments to design scent-tracking robots equipped with his eNose, an electronic nose that one day could detect odors such as that from an explosive mine.

To test Sobel and Porter's smell hypothesis, the UC Berkeley researchers soaked a 33-foot (10-meter) string in chocolate essence and laid it in the grass outside Barker Hall, located at the northwest corner of the UC Berkeley campus. They then garbed volunteers to block their senses of sight, hearing and touch, eliminating all clues other than smell to guide them along the trail. Sniffing like bloodhounds, two-thirds of 32 subjects were able to follow the chocolate scent to the end of the trail within three attempts. All volunteers zigzagged along the trail in the same way that tracking dogs follow a scent.

The researchers then trained four of these volunteers to see if they could improve. All were able to double their speed along the track within just a few days and deviated much less from the scent trail than on their first attempts. The researchers measured subjects' sniffs and noticed that the faster the subjects moved along the trail, the more rapid their sniffing - just as with dogs, though not as fast as the six sniffs per second rate exhibited by dogs.
The big question, however, was whether two nostrils allow scent localization in the same way that a human's two ears and eyes help locate sounds and sights.

To further test this, the researchers devised an ingenious nasal "prism" that mixed scents from the outside world and then presented this to both nostrils, so that there was no difference between what the nostrils smelled. The four subjects were half as accurate at tracking smells under these conditions.
Independent measurements showed that a human's two nostrils sample odors from distinct areas separated by approximately 1.5 inches (3.5 centimeters), more than enough distance to distinguish the edge of a scent plume.
All of these experiments put the lie to a common assumption that humans are lousy smellers compared to all other mammals. While it's true that humans are predominantly visual creatures, Sobel said, their olfactory sense can be compared to that of dogs and other mammals.

"Our sense of smell is less keen partly because we put less demand on it," Porter said. "But if people practice sniffing smells, they can get really good at it."

The work, which will be published in the journal's January 2007 issue, was supported by the Army Research Office and the National Institute on Deafness and other Communication Disorders of the National Institutes of Health.

Note: This story has been adapted from a news release issued by University of California - Berkeley.

The Advanced Cognitive Training for Independent and Vital Elderly, or ACTIVE, Study is the first randomized, controlled trial to demonstrate long-lasting, positive effects of brief cognitive training in older adults. However, testing indicated that the training did not improve the participants' ability to tackle everyday tasks, and more research is needed to translate the findings from the laboratory into interventions that prove effective at home.
The ACTIVE trial was funded by the National Institute on Aging (NIA) and the National Institute of Nursing Research (NINR), both components of NIH. Sherry L. Willis, Ph.D., of Pennsylvania State University in State College, Pa., and co-authors report the findings on behalf of ACTIVE investigators at the study's six sites: Hebrew SeniorLife, Boston; Indiana University School of Medicine, Indianapolis; Johns Hopkins University, Baltimore; Pennsylvania State University; University of Alabama at Birmingham; and University of Florida, Gainesville (in collaboration with Wayne State University, Detroit), and the data coordinating center at the New England Research Institutes, Watertown, Mass.

"This large trial found that community-dwelling seniors who received cognitive training had less of a decline in certain thinking skills than their peers who did not have training. The study addresses a very important hypothesis--that interventions can be designed to maintain cognitive function," says NIA Director Richard J. Hodes, M.D. "The challenge now is to further examine these interventions and others to see how they can be employed in real-world settings."

"Cognitive decline is known to precede loss of functional ability in older adults. It affects everyday activities such as driving or following instructions on a medicine bottle," says NINR Director Patricia A. Grady, Ph.D., R.N. "Research to identify effective ways of delaying this decline is important because it may help individuals, and our aging citizenry, maintain greater independence as they grow older."

The ACTIVE Study included 2,802 adults aged 65 and older who were living independently and had normal cognitive and functional status at the beginning of the study. Participants were randomly assigned to four groups. Three groups took part in training that targeted a specific cognitive ability--memory, reasoning or speed of processing. The fourth group received no cognitive training.

People in the three intervention groups attended up to 10 training sessions lasting 60 to 75 minutes each, over a five- to six-week time period. The memory group learned strategies for remembering word lists and sequences of items, text, and story ideas and details. The reasoning group learned strategies for finding the pattern in a letter or word series and identifying the next item in a series. The speed-of-processing group learned ways to identify an object on a computer screen at increasingly brief exposures, while quickly noting where another object was located on the screen.

After the initial training, 60 percent of those who completed the initial training took part in 75-minute "booster" sessions designed to maintain improvements gained from the initial sessions.

The investigators tested the participants at baseline, after the intervention and annually over five years. They found:

Immediately after the initial training, 87 percent of the speed-training group, 74 percent of the reasoning group and 26 percent of the memory group showed improvement in the skills taught.

After five years, people in each group performed better on tests in their respective areas of training than did people in the control group. The reasoning-training and speed-training groups who received booster training had the greatest benefit.

"The improvements seen after the training roughly counteract the degree of decline in cognitive performance that we would expect to see over a seven- to 14-year period among older people without dementia," says Dr. Willis.
The researchers also looked at the training's effects on participants' everyday lives. After five years, all three intervention groups reported less difficulty than the control group in tasks such as preparing meals, managing money and doing housework. Only the effect of reasoning training on self-reported performance of daily tasks was statistically significant. Those who received speed-of-processing training and follow-up booster training scored better on how quickly and accurately they could find items on a pantry shelf, make change, read medicine dosing instructions, place telephone calls and react to road traffic signs.

"Beyond middle age, people worry about their mental sharpness getting 'rusty.' This study offers hope that cognitive training may be useful," notes Richard Suzman, Ph.D., director of the NIA's Behavioral and Social Research Program, which sponsored the work. "ACTIVE has shown that relatively brief targeted cognitive exercises can produce durable changes in the skills taught. I would now like to see studies aimed at producing more generalized changes, perhaps through more intensive and broader interventions."

Recently some scientists have raised doubts about this classic genetic system to study ancient migrations of people and to estimate the populations of people or animals as they existed tens of thousands of years ago.
But University of Florida researchers writing this month in an online edition of Science validate the approach, which involves tracking sequences of mitochondrial DNA, also known as mtDNA.

"The study of mtDNA has helped to demonstrate the African origin of our species and the relationship between living humans and the Neanderthals," said Connie Mulligan, an associate professor of anthropology in the College of Liberal Arts and Sciences and an assistant director of the UF Genetics Institute. "MtDNA data have also been used to establish the time and route of major events in human history, such as the expansion of Neolithic farmers into Europe, and the settlement of the New World."

MtDNA has made headlines recently because of initiatives such as the National Genographic Project, a multimillion-dollar endeavor to reconstruct humanity's ancient migrations, and because of well-publicized efforts to track the ancestral roots of Oprah Winfrey and other personalities.

Located within the hundreds of energy-producing mitochondria that lie outside the nucleus of our cells, mtDNA is unlike the DNA inside the nucleus of a cell that contains genes from both of our parents -- in people and animals mtDNA is exclusively passed from mothers to their children.

For humans, this means that all of the mtDNA in our cells are copies of our mothers' mtDNA, which in turn were copies of their mothers' mtDNA. In this way, mtDNA progresses through the ages, springing from what many scientists believe was a common ancestral mother.

But over the eons, random mutations enter the genetic code of all species. By tracking similarities and differences of mtDNA, scientists gain insight about the size of groups and how they moved around the world.

"When you look at ancient migration, you're always asking the question, 'How big was the population, how many were there?'" said Michael Miyamoto, a professor and associate chairman of zoology in UF's College of Liberal Arts and Sciences. "The field has worked from the premise that the more mtDNA variation you saw, the larger the population was that carried that variation, just like there would be a greater diversity of T-shirts or shoes within a larger population than a smaller population."

However, the connection between mtDNA and population size was questioned this year when French scientists analyzed vast groups of gene sequences from more than 3,000 animal species. They speculated that an evolutionary tendency for species to keep helpful genes and sift out detrimental ones, called "natural selection," preferentially affects mitochondrial diversity, making mtDNA less useful for population size estimates.

"From a conservation perspective, when scientists look at census counts of animals and how the population size may be increasing or decreasing, the study of mtDNA tells us about the level of genetic diversity in a population, which is important in making conservation decisions on endangered species," Mulligan said. "If this approach were not credible, it could potentially have a bearing on future policy decisions, as well as affect literally hundreds of previous studies on humans and other mammals."

UF Genetics Institute scientists analyzed publicly available mtDNA datasets of 47 species of mammals -- a subset of the animals that were in the French study -- as well as associated data on protein diversity in the same species. A greater variety of proteins indicates more diverse DNA, because DNA contains a species' blueprints for manufacturing protein -- and the French scientists agreed that protein diversity did correlate with population size.

All that remained for UF researchers to do to reinstate mtDNA diversity as indicative of population size was to determine that protein diversity and mtDNA diversity were correlated.

"The researchers showed a correlation between mitochondrial DNA and genetic variation in a way that has never been done before," said Marc Allard, an associate professor of biology at George Washington University who was not involved in the study. "Population geneticists have used mitochondria for all kinds of work for 20 years, and to think that mtDNA didn't correlate with population size was clearly going against the dogma. This study shows the dogma is safe in mammals and probably in vertebrates, as well."

Note: This story has been adapted from a news release issued by University of Florida.

A world-famous British scientist failed to disclose that he held a paid consultancy with a chemical company for more than 20 years while investigating cancer risks in the industry, the Guardian can reveal.

Sir Richard Doll, the celebrated epidemiologist [epidemiology is the science of how diseases occur and spread] who established that smoking causes lung cancer, was receiving a consultancy fee of $1,500 a day in the mid-1980s from Monsanto, then a major chemical company and now better known for its GM crops business.

While he was being paid by Monsanto, Sir Richard wrote to a royal Australian commission investigating the potential cancer-causing properties of Agent Orange, made by Monsanto and used by the US in the Vietnam war. Sir Richard said there was no evidence that the chemical caused cancer.

Documents seen by the Guardian reveal that Sir Richard was also paid a £15,000 fee by the Chemical Manufacturers Association and two other major companies, Dow Chemicals and ICI, for a review that largely cleared vinyl chloride, used in plastics, of any link with cancers apart from liver cancer - a conclusion with which the World Health Organisation disagrees. Sir Richard's review was used by the manufacturers' trade association to defend the chemical for more than a decade.

The revelations will dismay scientists and other admirers of Sir Richard's pioneering work and fuel a rift between the majority who support his view that the evidence shows cancer is a product of modern lifestyles and those environmentalists who argue that chemicals and pollution must be to blame for soaring cancer rates.

Yesterday Sir Richard Peto, the Oxford-based epidemiologist who worked closely with him, said the allegations came from those who wanted to damage Sir Richard's reputation for their own reasons. Sir Richard had always been open about his links with industry and gave all his fees to Green College, Oxford, the postgraduate institution he founded, he said.

Professor John Toy, medical director of Cancer Research UK, which funded much of Sir Richard's work, said times had changed and the accusations must be put into context. "Richard Doll's lifelong service to public health has saved millions of lives. His pioneering work demonstrated the link between smoking and lung cancer and paved the way towards current efforts to reduce tobacco's death toll," he said. "In the days he was publishing it was not automatic for potential conflicts of interest to be declared in scientific papers."

But a Swedish professor who believes that some of Sir Richard's work has led to the underestimation of the role of chemicals in causing cancers said that transparency was all-important. "It's OK for any scientist to be a consultant to anybody, but then this should be reported in the papers that you publish," said Lennart Hardell of University Hospital, Orebro.

Sir Richard died last year. Among his papers in the Wellcome Foundation library archive is a contract he signed with Monsanto. Dated April 29 1986, it extends for a year the consulting agreement that began on May 10 1979 and offers improved terms. "During the one-year period of this extension your consulting fee shall be $1,500 per day," it says.

Monsanto said yesterday it did not know how much work Sir Richard did for the company, but said he was an expert witness for Solutia, a chemical business spun off from Monsanto, as recently as 2000.

Those anxious feelings are even more intense during the holidays.

Just over three-fourths of the people in Canada, 76 per cent, said they feel stress in their daily lives frequently or sometimes. Canadians were most likely to name their jobs, 32 per cent, or their finances, 28 per cent, as the most important causes of that stress.

Spaniards, 61 per cent, were not as wound up as those in most other countries polled. And they could all take a lesson from Mexico, where more than half of Mexicans said they rarely or never experience stress in their daily lives.

But that is certainly not the experience for most people in the 10 countries polled - especially women.

When the word "stress" was mentioned to Heidi Zabit of Durham, Conn., recently, it seemed to touch a bundle of nerves.

"My life is just so stressful right now I'm exploding all over the place," said Zabit, a paralegal and single mother of three boys. "Financially, the stresses are putting me under the table. After a full day of work, we finish dinner and do homework. By 9 p.m., I'm fried.

"And it's magnified by the holidays," she said. "They emotionally string us all out, they string our kids out, as far as hopes and expectations."

Germans feel stress more intensely than those in other countries polled. People in the U.S. cite financial pressures as the top worry. About half the people in Britain said they frequently or sometimes felt life was beyond their control, the highest level in the 10 countries surveyed.

In most of those countries, men were more likely to say their lives were never out of control.

"The idea that we French lead the good life is totally utopian," said Pascale Mongay, a counsellor at a private Paris tutoring firm.

"We are as stressed as anyone," she said.

Her paintings depict animals, outer space, people, children, flowers and Jesus Christ.

She's been on the talk show circuit, astonishing hosts like Oprah Winfrey and Montel Williams with her paintings.

On Saturday, the homeschooled youngster attended her first show in Idaho outside her hometown on the Panhandle.

She says she wants to continue to paint _ but has bigger plans of helping poor and orphaned kids in Europe and Africa.