A new brain scan shows what it looks like when a person runs out of patience or loses self-control.

It would explain why someone who works very hard not to take a second helping of lasagna at dinner winds up taking two pieces of cake at desert. The study could also modify previous thinking that considered self-control to be like a muscle.

University of Iowa neuroscientist William Hedgcock confirms previous studies that show self-control is a finite commodity that is depleted by use. Once the pool has dried up, we're less likely to keep our cool the next time we're faced with a situation that requires self-control.

But Hedgcock's study is the first to actually show it happening in the brain, using Functional Magnetic Resonance Imaging (FMRI) images that scan people as they perform self-control tasks, the Journal of Consumer Psychology reports.

The images show the anterior cingulate cortex (ACC) fires with equal intensity throughout the task. ACC is the part of the brain that recognises a situation in which self-control is needed and says: "Heads up, there are multiple responses to this situation and some might not be good."

However, the dorsolateral prefrontal cortex (DLPFC) fires with less intensity after prior exertion of self-control. DLPFC is the part of the brain that manages self-control and says: "I really want to do the dumb thing, but I should overcome that impulse and do the smart thing".

Hedgcock said that loss of activity in the DLPFC might be the person's self-control draining away. The stable activity in the ACC suggests people have no problem recognising a temptation. Although they keep fighting, they have a harder and harder time not giving in.

Researchers gathered their images by placing subjects in an MRI scanner and then had them perform two self-control tasks-the first involved ignoring words that flashed on a computer screen, while the second involved choosing preferred options.

Hedgcock says the study is an important step in trying to determine a clearer definition of self-control and to figure out why people do things they know aren't good for them.

One possible implication is crafting better programs to help people who are trying to break addictions to things like food, shopping, drugs, or alcohol.

A diet high in cholesterol may help people with a fatal genetic disease which damages the brain, according to early studies in mice.

Patients with Pelizaeus-Merzbacher disease struggle to produce a fatty sheath around their nerves, which is essential for function.

A study, published in Nature Medicine, showed that a high-cholesterol diet could increase production.

The authors said the mice "improved dramatically".

Pelizaeus-Merzbacher disease (PMD) is one of many leukodystrophies in which patients struggle to produce the myelin sheath. It protects nerve fibres and helps messages pass along the nerves.

Without the sheath, messages do not travel down the nerve - resulting in a range of problems including movement and cognition.

Researchers at the Max Planck Institute of Experimental Medicine, in Germany, performed a trial on mice with the disease and fed them a high cholesterol diet.
'Striking potential'

The first tests were on mice when they were six weeks old, after signs of PMD had already emerged. Those fed a normal diet continued to get worse, while those fed a cholesterol-enriched diet stabilised.

"This six-week-long cholesterol treatment delayed the decline in motor co-ordination," the scientists said.

Further tests showed that starting the diet early was more beneficial, leading the researchers to conclude that in mice "treatment should begin early in life and continue into adulthood".

This study was only in mice, meaning it is not known if there would be a similar effect in people - or if there would, how early treatment would have to start.

The authors of the report said: "Dietary cholesterol does not cure PMD, but has a striking potential to relieve defects."

It is thought the cholesterol frees up a "traffic jam" inside cells in the brain. The disease is caused by producing too much of a protein needed in myelin, which then becomes stuck inside the cells. It is thought the extra cholesterol helps to free up the protein.

A novel form of vitamin B3 found in milk in small quantities produces remarkable health benefits in mice when high doses are administered, a new study has shown.

The findings revealed that high doses of the vitamin precursor, nicotinamide riboside (NR) - a cousin of niacin - prevent obesity in mice that are fed a fatty diet, and also increase muscle performance, improve energy expenditure and prevent diabetes development, all without side effects.

Researchers at Weill Cornell Medical College and the Polytechnic School in Lausanne, Switzerland conducted the study.

The Swiss researchers, led by Dr. Johan Auwerx, performed the mouse experiments, while the ability to give the animals sufficient doses of NR was made possible by Weill Cornell Medical College researchers, who played key roles in uncovering the biological story of NR.

"This study is very important. It shows that in animals, the use of NR offers the health benefits of a low-calorie diet and exercise - without doing either one," said Dr. Anthony Sauve, associate professor of Pharmacology at Weill Cornell Medical College.

Dr. Sauve is the pharmacologist and organic chemist who has invented a simple method for efficiently synthesizing NR in large scale. He was first to show that NR increases nicotinamide adenine dinucleotide (NAD) levels in mammalian cells. NAD is a central player in energy metabolism. He has pioneered research into the compound, and he is a leader in investigating how NAD can signal adaptation in cells and in physiology.

"The research also suggests that the effects of NR could be even broader," Dr. Sauve stated.

"The bottom line is that NR improves the function of mitochondria, the cell's energy factories. Mitochondrial decline is the hallmark of many diseases associated with aging, such as cancer and neurodegeneration, and NR supplementation boosts mitochondrial functioning," he explained.

The Swiss researchers call NR a "hidden vitamin" that is believed to also be present in many other foods, although levels are low and difficult to measure. Nevertheless, the effects of NR on metabolism "are nothing short of astonishing."

While the new study demonstrates that high doses of NR can largely prevent the negative health consequences of a poor diet in mice, Dr. Sauve stresses that the effects of high doses of the vitamin in humans have not been evaluated.

"It is important to keep in mind that the amount of NR in milk and other foods appears to be small. We don't know what effects NR would have in humans at relatively high doses," he said.

"Still, we have very encouraging evidence of benefits of NR and NAD augmentation in general from this animal study - and much more work to do," he added.

The finding was recently reported in the June 2012 issue of the journal, Cell Metabolism. (ANI)

There's no shortage of reasons that many Americans don't get enough sleep: stress, obesity, late-night shifts on the job, to name just a few. Now new research suggests another factor to consider as well their race or ethnicity.

In two presentations at the annual meeting of the Associated Professional Sleep Societies in Boston, scientists report that the amount and quality of sleep people get each night vary across racial and ethnic lines. In one study, researchers found that blacks and Asians don't sleep as much as whites do, while another study showed that foreign-born Americans are less likely to report having sleep problems than those born in the U.S.

A better understanding of these discrepancies could help researchers improve the sleep habits of particular groups a potential public-health boon, considering that inadequate sleep is increasingly associated with greater risks of chronic conditions like heart disease, diabetes, obesity and certain cancers.

For the first study, led by Mercedes Carnethon, an associate professor of preventive medicine at Northwestern University, researchers randomly selected 439 Chicago-area adults from the phone book to participate. The volunteers, aged 35 to 64, were of white, black, Hispanic or Asian descent. Researchers screened the participants for sleep disorders like sleep apnea, and then asked them to wear a wrist monitor that detected their movements and determined how much time they spent sleeping over a period of seven days. The participants also self-reported the amount and quality of sleep they got each night.

Overall, the researchers found, blacks, Hispanics and Asians slept less than whites. Blacks got 6.8 hours of sleep a night on average, compared with 6.9 hours for Hispanics and Asians, and 7.4 hours a night for whites. The differences in sleep times persisted even after the researchers adjusted for other factors known to interfere with sleep, such as weight, diabetes status, high blood pressure and other heart disease risk factors. The study authors also accounted for socioeconomic factors like low education and low income, both of which can increase stress and disrupt sleep.

Interestingly, despite the fact that every racial group got less sleep than whites, only blacks reported suffering poor sleep quality and only Asians reported significant levels of daytime sleepiness. The latter finding was particularly surprising, since Asians tended to have lower body mass indexes and higher or equal education levels as whites, but still showed shorter and poorer sleep. "It's one of our more compelling and interesting findings, and one we intend to explore in depth further," says Carnethon, who notes that there's very little data on the sleep habits of Asians.

The authors surmise that the majority of the differences in sleep patterns between races can be chalked up to environmental or even geographical factors rather than genes or physical characteristics like variations in facial structure that could interfere with breathing and sleep. For example, Carnethon notes that Chicago is a relatively segregated city, and blacks and Hispanics tend to live in areas with higher pollution, more mass transit noise and higher crimes rates than predominantly white neighborhoods, which can lead to stress and disturbed sleeping. "I think social factors are more likely to account for the race and ethnic differences we observed," she says.

In the other paper, presented by Dr. Abhishek Pandey of SUNY Downstate Medical Center, scientists compared nightly sleep duration between foreign-born Americans and those who were born in the U.S. Based on phone survey data collected on 434,849 participants in the National Health Interview Survey in 2004-10, the researchers found that U.S.-born residents were more likely to report longer sleep more than eight hours a night on average while African-born Americans reported the least, less than six hours a night. Indian-born Americans fell in between, getting six to eight hours of sleep on average per night. The differences held even after the researchers adjusted for factors that can affect sleep duration, such as weight, age, and health risk behaviors such as smoking and drinking alcohol.

But despite their shorter sleep, foreign-born Americans were 20% less likely to report getting insufficient sleep than their native-born counterparts. While the study wasn't designed to determine why a person's country of birth might have such a strong effect on their sleep patterns, Pandey says that cultural beliefs and attitudes about sleep may influence how people view the importance of getting enough nightly slumber. In a previous study of Afro-Caribbean men in Brooklyn, for example, Pandey says that about 60% reported short sleep, but weren't aware of the health effects of sleep deprivation.

Taken together, the findings suggest that when it comes to sleep, a individual's racial or ethnic heritage may not only help explain his or her sleep patterns, but also encourage certain groups to sleep longer by addressing culturally based misperceptions about healthy sleep. In the U.S., racial ancestry has a lot to do with how we live our lives whether we're awake or asleep.

According to World Health Organisation experts the answer is a resounding 'Yes'.

Diesel engine exhaust fumes can cause cancer and belong in the same potentially dangerous category as asbestos, arsenic and mustard gas, said WHO experts.

France-based International Agency for Research on Cancer (IARC), part of the WHO, reclassified diesel exhausts from its group 2A of probable carcinogens to its group 1 of substances that have definite links to cancer. The experts claimed their decision was unanimous and based on compelling scientific evidence. They urged people across the world to reduce exposure to diesel fumes as much as possible.

"The (expert) working group found that diesel exhaust is a cause of lung cancer and also noted a positive association with an increased risk of bladder cancer," it said in a statement.

The decision to reclassify diesel wasn't taken lightly and is the result of a week-long meeting of experts who analysed the latest scientific evidence on the carcinogenic potential of diesel and gasoline exhausts. It puts diesel fumes in the same risk category as noxious substances such as asbestos, arsenic, mustard gas, alcohol and tobacco.

Christopher Portier, chairman of the IARC working group, said the group's conclusion "was unanimous, that diesel engine exhaust causes lung cancer in humans". "Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide," he said in a statement.

These findings are ever more relevant in India where the petrol prices are skyrocketing compared to diesel and most auto-manufacturers come out with diesel versions of cars. Outside of Europe and India, diesel engines are almost entirely confined to commercial vehicles. German carmakers are trying to raise awareness for diesels in the United States, where the long distances travelled on highways suit diesel engines.

IARC noted that large populations all over the world are exposed to diesel exhaust in everyday life, whether through their jobs or in ambient air. "People are exposed not only to motor vehicle exhausts but also to exhausts from other diesel engines (such as diesel trains and ships) and from power generators," it said. IARC's director Christopher Wild said that against this background, Tuesday's conclusion "sends a strong signal that public health action is warranted".

"This emphasis is needed globally, including among the more vulnerable populations in developing countries where new technology and protective measures may otherwise take many years to be adopted," he said in a statement.

For the last two decades diesel engine exhaust was classified as possibly carcinogenic to humans 0 group 2A but an IARC advisory group has constantly recommended diesel's status be re-evaluated since 1998.

The global auto industry, on the other hand, had argued diesel fumes should be given a less high-risk rating to reflect tighter emissions standards.

Reacting to the decision, Allen Schaeffer, executive director of the Washington-based Diesel Technology Forum said diesel engine and equipment makers, fuel refiners and emissions control technology makers have invested billions of dollars in research into technologies and strategies to reduce emissions.

"New technology diesel engines, which use ultra-low sulphur diesel fuel, advanced engines and emissions control systems, are near zero emissions for nitrogen oxides, hydrocarbons and particulate matter," he said in a statement. A spokeswoman for the European Automobile Manufacturers' Association said she was surprised by the move and the industry would "have to study the findings in all their details". "These technologies have been developed to address precisely these concerns," Sigrid de Vries told Reuters. "The latest diesel technology is really very clean."

After the IARC report was issued, General Motors Co, said in a statement: "We will continue with our plans to introduce new fuel saving technologies and engines that run on alternate fuels, including diesel."

GM said diesel engines being made today have lower sulphur content and emit much less particulate matter than engines from a few years ago.

However, experts feel the findings will have little impact on auto-companies and won't force them to change plans their plans for expanding diesel fuel automobiles in the United States. About 5.5 percent of new autos, including light-duty pickup trucks, sold in the United States run on diesel, said Baum, and he said that figure is expected to rise to 8 or 9 percent by 2015. IARC said it had considered recent advances in technology which had cut levels of particulates and chemicals in exhaust fumes, particularly in developed economies, but said it was not yet clear how these might translate into health effects.

"Research into this question is needed," it said. "In addition, existing fuels and vehicles without these modifications will take many years to be replaced, particularly in less developed countries, where regulatory measures are currently also less stringent." IARC also said gasoline exhaust fumes should be classified as "probably carcinogenic to humans", a finding that was unchanged from its previous assessment in 1989.