Knowledge Update

​London, Jan 2 (IANS) Scientists have for the first time identified a mechanism that regulates rhythmic brain waves that play a key role in making our memories permanent.

Memories undergo a consolidation process which stabilises and makes them become stronger -- a process where brain waves play an important role, the study said. 

The study revealed that one of the brain waves -- sharp wave ripples (SWRs) -- needed for consolidating memories is dominated by synaptic inhibition. 

It helps the brain set what an individual has learned or experienced as a quick instant replay.

SWRs is one among the three major brain waves coming from the hippocampus region of the brain that plays a key role in our memory making.

"Our results were able to show that precisely timed synaptic inhibition is the current generator for sharp wave ripples," said Peter Jonas, Professor at the Institute of Science and Technology Austria (IST Austria).

In the study, conducted in mice, the team set out to find the SWR mechanism -- whether ripples are caused by a temporal modulation of excitation or of inhibition at connecting points in brain cells, or synapses. 

The findings showed that the frequency of both excitation and inhibitor events at the synapse increased during the SWR.

But, synaptic inhibition was found to dominate over excitation during the production of SWRs, which means synaptic inhibition is responsible for forming the shape and rhythm of sharp wave ripples. 

Finally, the researchers also identified the neurons -- PV+ interneurons -- that provide inhibitory output onto other neurons and are mainly responsible for creating SWRs.

"Inhibition ensures the precise timing of neuronal firing. This could be critically important for preplay or replay of neuronal activity sequences and the consolidation of memory. 

"Inhibition may be the crucial player to making memories permanent," explained Jian Gan, post-doctoral student at IST Austria, in the paper published in the journal Neuron.

​New York, Jan 1 (IANS) Premixed complementary foods sold in lower-income countries lack consistency in their nutritional content, a global analysis of infant cereals has revealed.

The findings suggest that there is a need for basic quality assurance services to improve nutritional consistency and healthy growth of infants from 6 to 24 months age.

Premixed infant cereals or complementary foods can be a vital source of the solid food needed for healthy child growth after the age of six months, when infants outgrow the nutrients provided by breast milk alone.

This conclusion was reached after researchers from Tufts University in the US analysed 108 commercially available premixed complementary foods from 22 low-and-middle-income countries.

The findings, published in the journal Maternal and Child Nutrition, said premixed complementary foods can be extremely effective at protecting infants against malnutrition and stunted growth.

"In countries where we sampled, some products can readily meet children's needs, but others fall far below requirements for both macro and micro-nutrients," said William Masters from Tufts University.

"Our results are a call to action for establishing and enforcing nutritional quality standards, which would help ensure access to lower-cost, higher-quality products and enable parents to meet their infants' needs more easily," he added.

Researchers said that childhood malnutrition was the main cause of stunted growth, that may lead to delayed mental development and poor school performance -- a serious and irreversible condition that affects individuals with greater risk for illness and death throughout their lives.

According to Unicef, nearly half of all deaths in children under age five are related to undernutrition, which is particularly widespread in Africa and Asia.

"A healthy child consuming breast milk alongside the average sampled complementary food would experience zinc and iron deficiency from six to nine months, and dietary fat deficiency at 12 months," the study said.

The study noted that nutritional content claims on packaging labels did not meet their reported caloric content.

"Slightly more than half of the products misreported protein, and two thirds misreported fat content. For zinc and iron, products exceeded labelled values about as often as they fell short," the study further added.

​Tokyo, Dec 26 (IANS) Examining cucumber seedlings germinated under the very weak gravity -- or microgravity -- conditions of the International Space Station, researchers from Japan's Tohoku University have discovered how a protein helps plants sense gravity to boost their chances of survival.

Plants are experts in survival and can control the direction of their roots to maximise the use of resources around them. 

Using specialised cells, they can sense gravity and redistribute hormones, called auxins, to stimulate growth and allow vital features of the plant to develop. 

However, a big puzzle is how this transport process occurs at a cellular level.

In this study, reported in the journal Nature Microgravity and using samples grown on board the International Space Station, the research team highlighted the valuable contribution of the gravity-sensitive CsPIN1 protein to this process. 

The role of the protein in facilitating the transport of the growth hormones had first been suggested in previous experiments conducted on Earth.

To gain further insight, the researchers loaded cucumber seeds into specially designed canisters, which were sent up to the space station. 

Cucumbers were chosen for the study as they -- like other "cucurbitaceous" seedlings such as melons, pumpkins and squash -- feature specialised protuberances, or pegs, whose formation is regulated by gravity. 

These pegs form during the plant's early growth stage to help the seedlings emerge from their hard seed coat and anchor the developing plant in the soil while its roots form.

The experiment showed that CsPIN1 protein can relocalise under the influence of gravity.

Specifically, this change in the position of protein was found to occur in the so-called transition zone of the cucumber seedling where the pegs develop. 

This behaviour stimulates the formation of a cellular canal capable of transporting growth hormones from one side of this zone to the other, the study said.

Put simply, these findings point towards the mechanism by which the seeds are able to turn on and off the growth of their anchoring pegs in relation to their orientation with respect to gravity. And, as result, boost their chances of survival.

​Tokyo, Dec 27 (IANS) The Japanese government has adopted a series of emergency measures to prevent deaths due to overwork, following the deaths of two employees of a prominent advertising agency that became public recently, officials said on Tuesday.

The measures, approved Monday by the Labour Ministry and published by financial daily Nikkei, aim to increase monitoring of companies to ensure compliance with overtime laws.

Besides conducting surprise inspections at companies, authorities will also publicly reveal the names of firms which have seen cases of "karoshi", or death caused by overwork, as also those which force their staff to work extra hours beyond the legally allowed limit of 80 hours overtime a month, Efe news reported.

In October, the government published a report in response to such cases, which showed nearly a fourth of the country's workforce could be exceeding this limit.

The new measures, which will come into effect in January 2017, also include steps to advise companies on labour laws and foster medical and psychological help for employees who may be suffering from fatigue or work-related stress.

Concern and debate over excess work has been revived in the archipelago after the suicide of a 24-year-old female employee of Dentsu - the leading advertising firm in Japan - was confirmed to be a case of "karoshi" in October.

She had reportedly worked 105 extra hours the month before her death, although the company records reflected overtime within the permissible limit.

Her family alleged the company had forced her to indicate lesser hours than those she had actually worked.

The young woman, who died in December 2015 and who had been hired only seven months earlier by the company, had previously tweeted about having worked up to 20 hours a day.

Days after the confirmation of her case as karoshi, the death of another Dentsu employee in 2013 was also established to have been caused by excessive work.

The Japanese government last year approved a law to address problems caused by excessive work, but the lack of rigor on recording of extra hours by firms, and the staff's willingness to extend their working hours to earn a bonus makes it difficult to control the practice.

​Washington, Dec 27 (IANS) The world's fastest land animal, the cheetah, is sprinting towards the edge of extinction, a new study warned, calling for urgent conservation actions to save these big cats.

The study published in the US journal Proceedings of the National Academy of Sciences on Monday, estimated that the cheetah's population has declined to just 7,100 globally, Xinhua news agency reports.

As a result, the researchers urged that the cheetah should be up-listed from "Vulnerable" to "Endangered" on the International Union for the Conservation of Nature's Red List of Threatened Species.

Sarah Durant of the Zoological Society of London and lead author of the study said this study represents the most comprehensive analysis of cheetah status to date.

"Given the secretive nature of this elusive cat, it has been difficult to gather hard information on the species, leading to its plight being overlooked," Durant said in a statement.

According to the researchers, even within guarded parks and reserves, cheetahs still face threats of human-wildlife conflict, prey loss due to excessive hunting by people, habitat loss and the illegal trafficking of cheetah parts and trade as exotic pets.

To make matters worse, as one of the world's most wide-ranging carnivores, 77 per cent of the cheetah's habitat falls outside of protected areas, which makes the animal especially vulnerable to human pressures.

"The take-away from this pinnacle study is that securing protected areas alone is not enough," said Kim Young-Overton, cheetah program director of the wild cat conservation group Panthera. 

​Melbourne, Dec 26 (IANS) An international team of astronomers has found a massive supercluster of galaxies that had previously gone undetected as it was hidden by stars and dust in the Milky Way.

The Vela supercluster is a huge mass that influenced the motion of our galaxy, said Professor Matthew Colless from Australian National University.

"This is one of the biggest concentrations of galaxies in the Universe -- possibly the biggest in the neighbourhood of our Galaxy, but that will need to be confirmed by further study," Colless added.

"The gravity of the Vela supercluster may explain the difference between the measured motion of the Milky Way through space and the motion predicted from the distribution of previously mapped galaxies," Colless, who used the Anglo-Australian telescope to measure distances for many galaxies, explained.

The research -- published in the journal Monthly Notices of the Royal Astronomical Society -- involved astronomers based in South Africa, Australia and Europe. 

Two new Australian surveys starting in 2017 will confirm the size of the Vela supercluster, according to the researchers.

"The Taipan optical survey will measure galaxy distances over a bigger area around Vela, while the WALLABY radio survey will be able to peer through the densest parts of the Milky Way into the supercluster's heart," Colless pointed out.

​New York, Dec 26 (IANS) Scientists have identified a link between Huntington's disease and dysfunction in a section of brain structures that are critical for movement and impulse control.

Huntington's disease is characterised by the progressive loss of nerve cells in the brain and affects approximately one in 10,000 people. This fatal disorder is caused by a hereditary defect in a single gene.

According to the study, led by researchers at the Northwestern University in Illinois, the disease is caused by a dysfunction in the subthalamic nucleus -- a component of the basal ganglia which is a group of brain structures critical for movement and impulse control.

The findings may explain the causes of the debilitating symptoms such as as loss of motor and cognitive function, depression and personality changes that typically manifest in adulthood, as well as loss of brain tissue as the disease progresses.

For the study, the researchers used genetically engineered mice to carry the Huntington's disease gene. They discovered that the electrical activity of the subthalamic nucleus was lost. 

Impaired subthalamic activity was caused by anomalous receptor signalling, leading to defective energy metabolism and accumulation of damaging oxidants. 

In addition, the abnormalities in the subthalamic nucleus was found to occur earlier than in other brain regions and that subthalamic nucleus nerve cells progressively degenerate as the mice age, mirroring the human pathology of Huntington's disease.

"Our findings suggest early problems in the subthalamic nucleus not only contribute to the symptoms of Huntington's disease, but are also likely to impair the processing capacity and health of other brain structures, more traditionally associated with the disease," said Mark Bevan, professor at Northwestern University. 

A better understanding of aberrant brain receptor signaling that leads to nerve cell dysfunction could reveal a target for therapy, the researchers said.

The study was published in the journal eLife.

​New York, Dec 26 (IANS) Researchers have developed a synthetic version of a cardiac stem cell that could offer therapeutic benefits comparable to those from natural stem cells and could reduce some of the risks associated with stem cell therapies.

Stem cell therapies aid damaged tissue in repairing itself by secreting "paracrine factors," including proteins and genetic materials.

While stem cell therapies can be effective, they are also associated with some risks of both tumour growth and immune rejection. 

Also, the cells themselves are very fragile, requiring careful storage and a multi-step process of typing and characterisation before they can be used.

"The synthetic cells operate much the same way a deactivated vaccine works," said Ke Cheng, Associate Professor at North Carolina State University in the US.

"Their membranes allow them to bypass the immune response, bind to cardiac tissue, release the growth factors and generate repair, but they cannot amplify by themselves. So you get the benefits of stem cell therapy without risks," Cheng explained.

In this study, reported in the journal Nature Communications, the researchers created the synthetic version of a cardiac stem cell that could be used in off-the-shelf applications. 

When tested in vitro, it was found to promote the growth of cardiac muscle cells. 

The synthetic stem cells are much more durable than human stem cells, and could tolerate harsh freezing and thawing. 

They also do not have to be derived from the patient's own cells and the manufacturing process can be used with any type of stem cell, said the study.

"We are hoping that this may be a first step toward a truly off-the-shelf stem cell product that would enable people to receive beneficial stem cell therapies when they're needed, without costly delays," Cheng said.

London, Dec 26 (IANS) Listening to sounds such as music and noise has a significant effect on an individuals' moods and emotions, possibly as a result of brain dopamine regulation -- a neurotransmitter strongly involved in emotional behaviour and mood regulation, researchers have found.

However, the differences in dopamine receptors may drive the differences between individuals, the researchers said.

The study revealed that a functional variation in dopamine D2 receptor (DRD2) gene modulates the impact of music as opposed to noise on mood states and emotion-related prefrontal and striatal brain activity.

"Our results suggest that even a non-pharmacological intervention such as music might regulate mood and emotional responses at both the behavioural and neuronal level," said Elvira Brattico, Professor at Aarhus University in Denmark.

For the study, 38 healthy participants were recruited, with 26 of them having a specific "GG variant" of DRD2 and 12 a "GT variant". They underwent functional magnetic resonance imaging (fMRI) during performance of an implicit emotion-processing task while listening to music or noise.

The results showed that in participants with DRD2GG receptors the mood improved after music exposure, whereas in GT partipants mood deteriorated after noise exposure.

Moreover, the music, as opposed to noise environment, decreased the striatal activity of GT subjects as well as the prefrontal activity of GG subjects while processing emotional faces. 

These findings suggest that genetic variability of dopamine receptors affects sound environment modulations of mood and emotion processing, the researchers suggested. 

Importantly, these study encourages the search for personalised music-based interventions for the treatment of brain disorders associated with aberrant dopaminergic neurotransmission as well as abnormal mood and emotion-related brain activity, Brattico said, in the paper published in the journal Neuroscience.

​London, Dec 26 (IANS) If a recently proposed combination of three particular drugs is used, the devastating elephantiasis disease can be prevented or treated rapidly using fewer rounds of drugs, a new research has found.

Lymphatic filariasis -- commonly known as elephantiasis -- is a neglected tropical disease, which causes serious damage to the lymphatic system. 

A large proportion of the billion people living with the threat of transmission of this disabling parasitic disease is in India, Indonesia and Myanmar where the triple drug combination could be used, the researchers said.

"Our results show that this regimen could potentially overcome important issues plagued by elimination campaigns, by making elimination as a public health problem achievable in a few years," said first author of the study Mike Irvine from the University of British Columbia in Canada.

Lymphatic filariasis is caused by parasitic worms, and is transmitted to humans by mosquitoes.

Many people with the disease develop elephantiasis causing pain and profound disfigurement -- such as large swelling of the arms, legs or genitals -- and leading to permanent disability. 

These patients are not only physically disabled, but suffer mental, social and financial losses, contributing to stigma and poverty.

Currently, people with Lymphatic filariasis require multiple rounds of treatment -- but if the drugs ivermectin, diethylcarbamazine, and albendazole are used together recent clinical studies have shown that the drugs are more effective at killing the worms. 

The new modelling work - published in the journal The Lancet Infectious Diseases - showed that this meant that the number of rounds of mass drug administration needed to treat the disease may fall from many rounds to only two or three.

The models were developed at the University of Warwick in Britain, Erasmus Medical Centre in the Netherlands, and Notre Dame University in the US. 

All three models were in agreement in the effectiveness of the regimen in reducing the prevalence of disease. The researchers noted that more effective treatment with fewer drugs rounds is crucial in poorer countries where transmission is high but resources are low.

The World Health Organisation (WHO) has targeted the disease for elimination as a public health problem by the year 2020.