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) 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.​

​New York, June 7 (IANS) Scientists have discovered a ‘third gene' that leads to the development of the common neurodegenerative disease, a study said.

The study provided evidence that mutations in gene TMEM230 caused Parkinson's disease -- a disorder of the central nervous system that affects movement, often including tremors.

“The study showed that mutations in this new gene lead to pathologically and clinically proven cases of the disease," said led researcher Teepu Siddique, Professor at Northwestern University in the US.

The findings showed that the gene is responsible for producing a protein involved in packaging the neurotransmitter dopamine in neurons. Loss of dopamine-producing neurons is a defining characteristic of Parkinson's disease.

Also, individuals with this gene mutation showed both clinical characteristics of the disease -- symptoms like tremors, slow movement and stiffness -- as well as pathological evidence in the brain -- loss of dopamine neurons and abnormal accumulations of proteins inside surviving neurons.

"This particular gene causing Parkinson's disease is not just limited to one population in North America," Siddique said.

"It's worldwide, found in very different ethnic and environmental conditions. These mutations are that strong."

Further, TMEM230 was also found to encode a protein that extends across the membrane of tiny sacks inside neurons called synaptic vesicles, which store neurotransmitters before they are released from one cell to another.

The scientists hypothesised that the protein is involved in the movement of these vesicles.

"We believe that vesicle trafficking defects are a key mechanism of Parkinson's disease, not just for cases with this mutation, but a common pathway for the majority of cases," added Han-Xiang Deng, Professor at Northwestern University. 

"Our new findings suggest normalising synaptic vesicle trafficking may be a strategy for future therapeutic development. We can develop drugs to promote this critical pathway," Deng noted in the paper detailed in the journal Nature Genetics.

In the study, which stretched for 20 long years, the researchers performed genome-wide analysis on 65 members of a family, including 13 with the disease, in hopes of finding a common mutation that could explain the prevalence.​

​Beijing, June 7 (IANS) Concerned over increasing health problems, China has decided to provide 'family doctors' to every household in the country by 2020.

The State Council's Medical Reform Office said 200 cities will come under the service in 2016. In the following year, it plans to provide the facility to about 30 percent of China's population.

With a population of about 1.4 billion, of which 9 percent is elderly, China is faced with rising health problems such as cancer and obesity among others.

The problems have to do with various factors which range from pollution to sedentary lifestyle.

In 2015, over four million people were diagnosed with cancer and nearly three million died from it.

Family doctors are expected to serve as health guards for Chinese people, Xinhua news agency reported, quoting the National Health and Family Planning Commission.

A health official said the move will reduce healthcare costs and make it more accessible to public.

The doctors, to be put into services, will be from local hospitals and clinics and rural areas.

The public healthcare system is overburdened in China, which is faced with a shortage of doctors. The burgeoning middle class has given rise to growing privatization in the health sector.

According to state-run newspaper Global Times, there was an acute shortage of pediatrician in China: an average of 0.53 doctors for every 1,000 children.

According to WHO, China had 1.9 physicians per 1,000 people.

China ranked 95th globally in health expenditure per capita in 2013, according to the most recent World Bank data.​

​London, June 7 (IANS) Despite having a much simpler and smaller brain than that of primates, fish have the remarkable ability to distinguish between human faces, new research has found.

“Being able to distinguish between a large number of human faces is a surprisingly difficult task, mainly due to the fact that all human faces share the same basic features,” said first author Cait Newport from Oxford University.

“It has been hypothesised that this task is so difficult that it can only be accomplished by primates, which have a large and complex brain,” Newport noted.

To test this idea, the researchers wanted to determine if another animal with a smaller and simpler brain, and with no evolutionary need to recognise human faces, was still able to do so.

In the study, archerfish -- a species of tropical fish well known for its ability to spit jets of water to knock down aerial prey -- were presented with two images of human faces and trained to choose one of them using their jets. 

The fish were then presented with the learned face and a series of new faces and were able to correctly choose the face they had initially learned to recognise. 

They were able to perform this task even when more obvious features, such as head shape and colour, were removed from the images.

The fish were highly accurate when selecting the correct face, reaching an average peak performance of 81 per cent in the first experiment (picking the previously learned face from 44 new faces) and 86 per cent in the second experiment (in which facial features such as brightness and colour were standardised).

The study was published in the journal Scientific Reports.

“Once the fish had learned to recognize a face, we then showed them the same face, as well as a series of new ones. In all cases, the fish continued to spit at the face they had been trained to recognize, proving that they were capable of telling the two apart,” Newport said.

“The fact that archerfish can learn this task suggests that complicated brains are not necessarily needed to recognise human faces,” Newport noted.​