Knowledge Update

​Wellington, June 10 (IANS) Air pollution, including environmental and household air pollution, has emerged as the leading risk factor for stroke globally, finds a new study.

The findings showed that about a third (29.2 per cent) of global disability associated with stroke such as loss of vision and/or speech, paralysis and confusion, is linked to air pollution (including environmental air pollution and household air pollution). 

This is especially high in developing countries -- 33.7 per cent vs 10.2 per cent in developed countries, the researchers said.

From 1990 to 2013, stroke associated with environmental air pollution showed an increase by over 33 per cent worldwide. However, second-hand smoke saw a decrease by 31 per cent between the same period. 

"A striking finding of our study is the unexpectedly high proportion of stroke burden attributable to environmental air pollution, especially in developing countries," said lead author Valery L Feigin, Professor at Auckland University of Technology in New Zealand. 

Also, over 90 per cent of the global burden of stroke was caused by modifiable risk factors and 74 per cent of them are behavioural risk factors such as smoking, poor diet and low physical activity. 

"Controlling these risk factors could prevent about three-quarters of strokes worldwide," Feigin added.

Further, air pollution, environmental risks, tobacco smoke, high blood pressure and dietary risks were the other risk factors found for stroke in developing countries compared to developed countries.

Household air pollution was found to be an important risk factor for stroke in central, eastern and western sub-Saharan Africa as well as south Asia.

Every year, approximately 15 million people worldwide suffer a stroke. High blood pressure, diet low in fruit, high body mass index (BMI), diet high in sodium, smoking, diet low in vegetables, environmental air pollution, household pollution from solid fuels, diet low in whole grains and high blood sugar were found as the ten major risk factors for stroke. 

"Our findings are important for helping national governments and international agencies to develop and prioritise public health programmes and policies," Feigin noted.

For the study, published in The Lancet Neurology journal, the team used data from the Global Burden of Disease Study to estimate the disease burden of stroke associated with 17 risk factors in 188 countries between 1990-2013. 

"Air pollution is not just a problem in big cities, but is also a global problem. It is one aspect of the fossil fuel and global warming problem, which is itself partly a result of westernisation and urbanisation, especially in India and China," the researchers concluded.​

​New York, June 10 (IANS) Large animals hunted for their parts -- such as elephant ivory and shark fins -- are in double jeopardy of extinction due to their large body size and high value, says a study.

The study reveals underappreciated risk to marine species similar to that of iconic terrestrial species.

"We typically assume that if a species is reduced to low numbers, individuals will be hard to find, hunters will stop hunting, and populations will be given a chance to recover," said one of the researchers Loren McClenachan of Colby College in Waterville, Maine, US. 

"But the extreme values of these species mean that without significant conservation intervention, they will be hunted to extinction," McClenachan noted.

In the new study, the researchers identified a taxonomically diverse group of more than 100 large marine and terrestrial species that are targeted for international luxury markets. 

They estimated the value of these species across three points of sale and explored the relationships among extinction risk, value, and body size. 

The analysis showed a threshold above which economic value is the key driver of extinction risk. 

Although lower-value species are influenced primarily by their biology, the most valuable species are at high risk of extinction no matter their size. 

Once mean product values are greater than $12,557 per kilogram, body size no longer drives risk, the report showed.

The researchers also uncovered important differences between marine and terrestrial species that point to elevated risk in the sea.

Although marine products are generally less valuable on a per kilogram basis, individual animals are still just as valuable as the most valuable terrestrial species. 

An individual whale shark, for example, is about as valuable as the most valuable terrestrial species: rhinoceroses and tigers.

The risk to marine species is not reduced for species with larger ranges as it is on land, either, the researchers said.

The findings appeared in the journal Current Biology. ​

Beijing, June 8 (IANS) Chinese children are much taller and stronger than they were four decades ago, with the height gap standing at 8 cm, a government survey showed on Wednesday.

The National Health and Family Planning Commission (NHFPC) surveyed 161,774 healthy children under seven-years-old from nine cities and their suburbs in 2015. 

Health authorities have conducted the survey once every 10 years since 1975, Xinhua news agency reported.

Taking children aged five to five-and-half years old for example, the boys on average measure 113.6 cm, 8 cm taller than boys in 1975 and 1.7 cm taller than boys in 2005, while girls have an average height of 112.5 cm, 8.2 cm more than four decades ago and 1.8 cm more than ten years ago, according to the 2015 survey results.

They also weigh 3.7 to 3.28 kg more than children four decades ago, the survey showed.

The physical development of the children surveyed surpassed the World Health Organisation's child growth standards, according to the NHFPC.

The weight and height gaps between urban children and rural children have also narrowed, according to the survey.

In 1975, urban boys aged four to five were on average 4 cm taller than their rural peers, but the gap was only 0.6 cm in 2015, while for girls of the same age the difference dropped from 4.3 cm to 0.4 cm.

​New York, June 8 (IANS) Scientists have concocted an artificial seawater medium that can be used to successfully cultivate abundant marine micro-organisms, a study says.

"We developed an artificial media which means you can make it in the lab; and anyone can order these chemicals and make this media anywhere in the world," said one of the researchers Cameron Thrash, assistant professor at Louisiana State University in the US.

The artificial seawater media consists of about 60 ingredients that include chemical elements such as calcium, sodium, magnesium plus organic and inorganic nitrogen, carbon, trace metals and B vitamins.

Prior to this discovery, many of the most abundant micro-organisms in the ocean that have been successfully cultured were done so with the aid of natural seawater media. 

Seawater is naturally low in nutrients, and many marine microbes are adapted to those conditions. 

The painstaking culturing process that includes filtering and sterilising the seawater can pose many challenges. 

First, it requires access to large volumes of seawater, which can be logistically challenging for research labs that are not located near the coast. 

Secondly, the composition of natural seawater is not clearly defined or understood. Therefore, it is difficult to characterise it physiologically. Thirdly, the composition of seawater at various times and places chemically changes.

To solve some of these challenges, the researchers created a complex yet defined artificial seawater media that is portable and reproducible. 

The findings were published in the open access journal mSphere.

Although there are other artificial seawater media available, this is the first time an artificial medium has led to the isolation of highly abundant marine microbes such as SAR11, a group of organisms that has been difficult to cultivate. 

This new tool may benefit genomics researchers, marine chemists and the microbial research community.​

New York, June 9 (IANS) Scientists have discovered that hair-like filaments on the surface of Geobacter bacteria exhibit electrical conductivity comparable to that of copper -- paving the way for the employment of biological materials in nanoscale electron devices.

Scientists from the University of Massachusetts at Amherst used X-ray diffraction to analyse the structure of the filaments called the pili. 

They found that the electronic arrangement and small molecular separation distances of less than 0.3 nanometres give the pili an excellent conductivity.

Although proteins are usually electrically insulating, the researchers said the study supports the concept that the pili of G. sulfurreducens represent a novel class of electronically functional proteins in which aromatic amino acids promote long-distance electron transport.

The research findings, published recently in the journal mBio, can provide useful feedback for studies targeting the enhancement of pili's electrical conductivity through genetic engineering.

It could subsequently be used to construct low-cost, non-toxic, nanoscale, biological sources of electricity for light-weight electronics and for bioremediation.​

​London, June 6 (IANS) Researchers have successfully identified the four keys that unlock the genetic code of skin cells and reprogramme them to start producing red blood cells instead.

The findings could lead to personalised red blood cells for those in need of blood transfusion, for instance, people suffering from chronic anemia -- a condition in which the patient has an insufficient amount of red blood cells.

"This is the first time anyone has ever succeeded in transforming skin cells into red blood cells, which is incredibly exciting," said lead author of the study Sandra Capellera from Lund University in Sweden.

"We have performed this experiment on mice, and the preliminary results indicate that it is also possible to reprogramme skin cells from humans into red blood cells,” Johan Flygare, who is also from Lund University, noted.

The study was published in the journal Cell Reports.

Every individual has a unique genetic code, which is a complete instruction manual describing exactly how all the cells in the body are formed. 

This instruction manual is stored in the form of a specific DNA sequence in the cell nucleus. All human cells -- brain, muscle, fat, bone and skin cells -- have the exact same code. 

The thing that distinguishes the cells is which chapter of the manual the cells are able to read. 

The research team wanted to find out how the cells open the chapter that contains instructions on how to produce red blood cells. 

Here is how the researchers got the skin cells to open the chapter describing red blood cells.

With the help of a retrovirus, they introduced different combinations of over 60 genes into the skin cells' genome, until one day they had successfully converted the skin cells into red blood cells. 

The study showed that out of 20,000 genes, only four are necessary to reprogramme skin cells to start producing red blood cells. Also, all four are necessary in order for it to work.​

New York, June 7 (IANS) Consuming a Mediterranean diet rich in vegetable fats such as olive oil or nuts does not lead to significant weight gain compared to a low-fat diet, finds a new research.

The findings showed that fats from nuts, fish and phenolic-rich vegetable oils found in the Mediterranean diet are healthier than fats from meat and processed foods.

"Our study shows that a Mediterranean diet rich in vegetable fats had little effect on bodyweight or waist circumference compared to people on a low-fat diet,” said lead author Ramon Estruch from the University of Barcelona, Spain. 

A Mediterranean diet has been known to reduce mortality, heart diseases as well as cancer.

However, the fear of eating an all fat diet means that a low-fat diet continues to be recommended as a means of weight loss, the researchers said.

"The study certainly does not imply that unrestricted diets with high levels of unhealthy fats such as butter, processed meat, sweetened beverages, deserts or fast foods are beneficial," Estruch added.

For the study, published in 'The Lancet Diabetes & Endocrinology' journal, the team included 7447 participants (men and women) aged 55-80 who were randomly assigned to one of three groups - an unrestricted calorie Mediterranean diet rich in olive oil (2543), an unrestricted calorie Mediterranean diet rich in nuts (2454), or a low-fat diet where the advice was to avoid all dietary fat (2450). 

After five years, the low-fat diet group (from 40 per cent to 37.4 per cent) showed a decrease in the total fat intake and both Mediterranean diet groups (40 per cent to 41.8 per cent in olive oil; 40.4 per cent to 42.2 per cent in nuts) showed slight increase. 

The percentage of energy intake from protein and carbohydrate decreased in both Mediterranean diet groups.

On average, participants in all three groups lost some weight with the greatest weight loss seen in the Mediterranean diet with olive oil group (0.88 kg weight reduction in the olive oil group, compared to 0.60 kg for the low-fat diet group and 0.40 kg for the nuts group). 

"Calorie-obsessed caveats and warnings about healthier, higher-fat choices such as nuts, phenolic-rich vegetable oils, yoghurt should also be dropped. We must abandon the myth that lower-fat, lower-calorie products lead to less weight gain," commented Dariush Mozaffarian, Professor at Tufts University in the US, in a linked article.​

​New York, June 7 (IANS) Further burnishing copper's reputation as an essential nutrient for human health, researchers have found that the metal plays a key role in metabolising fat.

"We find that copper is essential for breaking down fat cells so that they can be used for energy," said lead researcher Chris Chang, professor at the University of California - Berkeley.

"It acts as a regulator. The more copper there is, the more the fat is broken down,” Chang noted.

The nutrient is plentiful in foods such as oysters and other shellfish, leafy greens, mushrooms, seeds, nuts and beans.

“We think it would be worthwhile to study whether a deficiency in this nutrient could be linked to obesity and obesity-related diseases," Chang said.

"Copper is not something the body can make, so we need to get it through our diet," he pointed out.

But the researchers caution against ingesting copper supplements as a result of these study results.

Too much copper can lead to imbalances with other essential minerals, including zinc.

An adult's estimated average dietary requirement for copper is about 700 micrograms per day, according to Food and Nutrition Board, Institute of Medicine, National Academies of Sciences in the US.

The researchers made the copper-fat link using mice with a genetic mutation that causes the accumulation of copper in the liver. 

The findings appeared online in the journal Nature Chemical Biology.

The connection between copper and fat metabolism is not altogether surprising. The researchers actually found hints of the link in the field of animal husbandry.

"It had been noted in cattle that levels of copper in the feed would affect how fatty the meat was," Chang said. 

"This effect on fat deposits in animals was in the agricultural literature, but it hadn't been clear what the biochemical mechanisms were linking copper and fat," he noted.​

​Beijing, June 7 (IANS) China has begun establishing quantum communications networks in several cities, and is currently building a 1,000-km quantum communications line connecting Beijing and Shanghai.

New York, June 7 (IANS) Pandas do not like it hot and rising temperatures can also put pressure on their food supply by eliminating vast amounts of bamboo plants, researchers say.

"Higher climate temperatures would upset the entire system in the panda reserves and the wild, eliminating vast amounts of bamboo," said one of the researchers James Spotila, Professor at Drexel University in Philadelphia, Pennsylvania, US.

But burning out food sources is not the only problem when it comes to climate change. Rising temperatures are bad for pandas themselves, the researchers noted.

Giant pandas experience heat stress when temperatures climb above 25 degrees Celsius.

"They have to live at temperatures below that to stay healthy," Spotila said. 

"In nature, they actively seek out cool areas (microhabitats) in summer and move to higher elevations to avoid heat," he noted.

Working at the Chengdu Research Base in China, home of roughly 150 giant pandas, the researchers discovered that they have bigger appetites than originally believed.

Metabolism of pandas was actually just a little below what would be expected for a mammal of their size. Their rates were on-par for bears and came in just a little below seals, kangaroos and deer, the findings showed.

But past research placed the pandas' metabolism at a much lower rate.

The researchers believe that although the metabolism of giant pandas is higher than previously reported, there is more than enough bamboo in nature to keep pandas healthy and happy for years. That is, until rising global temperatures kill the plants off.

The findings were reported in the journal Scientific Reports.

"Unchecked climate change will undo all of the years of hard work by the Chinese to save their national icon," Spotila said.​