Knowledge Update

New York, May 11 (IANS) Low doses of a general anaesthetic drug is likely to reduce suicidal thoughts in patients with treatment-resistant depression, finds a new study.

The findings showed that repeatedly infusing low doses of ketamine in depressed patients with recurrent suicidal thoughts might help them in recovering rapidly. 

"Our finding that low doses of ketamine, when added on to current antidepressant medications quickly decreased suicidal thinking in depressed patients, is critically important because we don't have many safe, effective and easily available treatments for these patients," said Dawn Ionescu, lead researcher from Massachusetts General Hospital (MGH) in the US.

Having suicidal thoughts increases the risk that patients will attempt suicide. However, the risk of suicide attempts is 20 times higher in patients with depression than the general population. 

The study, published online in the Journal of Clinical Psychiatry, was designed not only to examine the antidepressant and anti-suicidal effects of repeated low-dose ketamine infusions, but also to examine the safety of increased ketamine dosage.

The team enrolled 14 patients with moderate to severe treatment-resistant depression who had suicidal thoughts for three months or longer and they received two weekly ketamine infusions over a three-week period. 

The initial dosage administered was 0.5 mg/kg over a 45-minute period -- about five times less than a typical anaesthetic dose -- and after the first three doses, it was increased to 0.75 mg/kg. 

The participants were assessed on measures of suicidal thinking, in which patients were directly asked to rank whether they had specific suicide-related thoughts, their frequency and intensity.

The results showed that most of them experienced a decrease in suicidal thinking, and seven achieved complete remission of suicidal thoughts at the end of the treatment period. 

"The study that aim to understand the mechanism by which ketamine and its metabolites work for people with suicidal thinking and depression may help us discover areas of the brain to target with new, even better therapeutic drugs," Ionescu concluded.​

​Tokyo, May 12 (IANS) After analysing a 3D map of 3,000 galaxies 13 billion light years from Earth, an international team led by Japanese researchers has found that theoretical physicist Albert Einstein's general theory of relativity is still valid.

Since it was discovered in the late 1990s that the universe is expanding at an accelerated rate, scientists have been trying to explain why.

The mysterious dark energy could be driving acceleration, or Einstein's theory of general relativity, which says gravity warps space and time, could be breaking down.

“We tested the theory of general relativity further than anyone else ever has. It's a privilege to be able to publish our results 100 years after Einstein proposed his theory," said project researcher Teppei Okumura from Kavli Institute for the Physics and Mathematics (Kavli IPMU) at University of Tokyo.

To test Einstein's theory, the team led by Okumura and colleagues, with researchers from Tohoku University and Kyoto University, used “FastSound Survey” data on more than 3,000 distant galaxies to analyze their velocities and clustering.

The results indicated that even far into the universe, general relativity is valid, giving further support that the expansion of the universe could be explained by a cosmological constant as proposed by Einstein in his theory of general relativity.

“Having started this project 12 years ago, it gives me great pleasure to finally see this result come out," added Karl Glazebrook, professor at Swinburne University of Technology who proposed the survey.

No one has been able to analyse galaxies more than 10 billion light years away but the team managed to break this barrier thanks to the FMOS (Fiber Multi-Object Spectrograph) on the Subaru Telescope which can analyse galaxies 12.4-14.7 billion light years away.

The details of the study were published in the Publications of the Astronomical Society of Japan.​

​New York, May 12 (IANS) Researchers from Harvard University have developed a flexible exosuit that reduces the energy required for walking when carrying a heavy load - helping people like soldiers, rescuers in emergency situations or hikers who frequently have to do so.

The exosuit reduced the amount of energy required while walking with a load - the metabolic cost - by 7.3 percent on an average.

The suit also significantly reduced the work done by the hip, knee and ankle joints, without impacting step frequency or length.

This suggests that the suit does not affect the wearers' freedom of movement but allows them to return to a walking profile closer to that of people walking without a load.

“Apart from assisting load carriers, we are exploring how the soft exosuit can be used to assist individuals with impaired movement, paving the way for the use of this technology in a wide range of people,” said Conor Walsh, the corresponding author.

The Harvard researchers used textiles to build their alternative to rigid exoskeletons which are heavier and can interfere with the natural movement of the joints, causing the wearer to change the way they walk.

The suit is composed of a waist belt, two thigh pieces and two calf straps, connected by cables to two motors mounted on a backpack.

The energy from the motors travels via the cables to the suit which transfers it to the wearer.

The suit becomes active only when it detects a walking motion.

It assists the hip and ankle joints which together contribute about 80 percent of the power produced by the leg joints during walking.

“Our results demonstrate for the first time that an autonomous soft exosuit can reduce the energy expenditure experienced by load carriers, possibly enhancing their overall gait performance,” Walsh added in a paper published in the Journal of NeuroEngineering and Rehabilitation.

Seven experienced load carriers who had no injuries or diseases of their muscles, joints or bones, walked on a treadmill at a constant speed of 1.5 meters per second while carrying a load equal to 30 percent of their body mass.

Researchers monitored the participants' metabolism, kinetics (forces that influence the movements of the body) and kinematics (extension or rotation of joints and muscles).

The researchers also analysed the participants' breathing, gait and muscle activation.

The device can also prove useful for people with physical impairments, the authors noted.​

​New York, May 11 (IANS) A team of US researchers has come up with a rough map of part of the brain that controls vision and leaves things out even when they are plainly in sight.

The frontal cortex is often seen as our “thinking cap,” associated with thinking and making decisions. But it's not commonly connected with vision. 

“Some people believe that the frontal cortex is not involved. The new research adds to previous evidence that it is,” said Dobromir Rahnev, psychologist at Georgia Institute of Technology.

“The 'thinking cap' of the brain controls and oversees the whole process, making it as essential to how we see as those other areas,” Rahnev explained. 

How that works also accounts for why we sometimes miss things right in front of us.

“We feel that our vision is like a camera, but that is utterly wrong," Rahnev said. 

Our brains aren't just seeing, they're actively constructing the visual scene and making decisions about it. 

Sometimes the frontal cortex is not expecting to see something so although it's in plain sight, it blots it out of consciousness, said the team that involved researchers from the University of California-Berkeley.

The frontal cortex sends a signal to move your attention onto the object you select.

“It does some of the combining with other information, and then it's probably the primary evaluator of what you think you saw,” Rahnev noted.

The findings were published in the journal of the Proceedings of the National Academy of Sciences.​

​London, May 11 (IANS) There is good news for mango lovers! You may soon be able to tell how ripe a mango is without having to taste it as researchers have identified a way to “sniff” the ripeness of the fruit.

They have identified the unique chemical signature of ripening for mangoes, a development that could lead to small hand-held electronic noses to detect the ripeness of not just mangoes but other fruits as well.

Mangoes are one of the most important and popular tropical fruits with India producing approximately 40 percent of the world's supply. 

"It is really important for people to be able to tell how ripe fruit is without having to taste it. This is important for fruit producers and supermarkets,” said lead researcher Paul Monks, professor at the University of Leicester in Britain.

The new research, published in the journal Metabolomics, has shown that is possible to 'sniff' the ripeness of mangoes.

"We used a novel fast-sensitive "electronic-nose" for sniffing volatile compounds from the ripening fruit. Popular supermarket species of mango were used. In particular, the work showed an increase in ester compounds -- the smell of pear drops -- was a particular marker of over ripe fruit," Monks noted.

The work has, for the first time, followed in real-time and detail the chemical signatures of ripening for mangoes, Monks said.

"There are some real potential applications of this research for making devices to be able to assess ripeness non-destructively. The information gained from the work could be used to develop small, hand-held electronic noses that could be deployed to assess fruit maturity prior to picking and thus determine the optimum point to harvest mature green mangoes,” he added.​

​London, May 11 (IANS) A long wait before asking for feedback about a service or product would increase the odds of getting a better review by your customers, researchers say.

The findings revealed that people who waited longer or travelled farther before authoring a review gave more favourable evaluations.

"If someone visited a particular restaurant in their home town and then in another state, he or she gave a better star rating when the restaurant was out of town," said lead author Nina Huang from Temple University in Pennsylvania.

The investigators analysed data from more than 166,000 online restaurant reviews on travel website TripAdvisor.com that provides reviews of travel-related content. 

They used a Google Maps application and information in the reviewer's profile to calculate the distance between the author's home and the restaurant.

The same positive effect occurred when reviewers waited two or more months versus one month or less to write a review. 

The researchers discovered that reviewers who experienced both time delay and greater physical distance from the restaurant gave the highest ratings. 

It might be wise to take a moment to distinguish between reviews written by locals versus travellers before judging a product or service, the authors noted in a paper published in the Journal of Consumer Psychology. 

"When people are reading a review, they assume it is objective," Huang noted, adding, "We found that reviews are not always as objective as we thought. Time and space distance is going to bias someone's evaluation of certain experiences."​

​New York, May 10 (IANS) Researchers including one of Indian origin from the US Department of Energy's Berkeley Lab have engineered a strain of bacteria that enables a "one-pot" method for producing advanced biofuels from a slurry of pre-treated plant material.

The Escherichia coli (E coli) is able to tolerate the liquid salt used to break apart plant biomass into sugary polymers. 

Developing ionic-liquid-tolerant bacteria eliminates the need to wash away the residual ionic liquid.

The achievement is a critical step in making biofuels a viable competitor to fossil fuels because it helps streamline the production process.

Being able to put everything together at one point, walk away, come back and then get your fuel, is a necessary step in moving forward with a biofuel economy," said principal investigator Aindrila Mukhopadhyay, vice president of the fuels' synthesis division at the Joint BioEnergy Institute (JBEI), Berkeley Lab. 

"The E coli we've developed gets us closer to that goal. It is like a chassis that we build other things onto, like the chassis of a car. It can be used to integrate multiple recent technologies to convert a renewable carbon source like switchgrass to an advanced jet fuel," he added.

The basic steps of biofuel production start with deconstructing, or taking apart, the cellulose, hemicellulose and lignin that are bound together in the complex plant structure. 

Enzymes are then added to release the sugars from that gooey mixture of cellulose and hemicellulose, a step called saccharification. 

Bacteria can then take that sugar and churn out the desired biofuel. 

The multiple steps are all done in separate pots.

Researchers pioneered the use of ionic liquids - salts that are liquid at room temperature - to tackle the deconstruction of plant material because of the efficiency with which the solvent works. 

E. coli remains the workhorse microbial host in synthetic biology and in the new study, using the ionic-liquid-tolerant E. coli strain, we can combine many earlier discoveries to create an advanced biofuel in a single pot," the authors noted.

"Ultimately, we hope to develop processes that are robust and simple where one can directly convert any renewable plant material to a final fuel in a single pot," Mukhopadhyay noted in a paper published in the journal Green Chemistry.​

​Sydney, May 9 (IANS) Although it may sound counterintuitive, researchers from the University of Adelaide say that the global increase in Type-1 diabetes is directly linked to advances in medical care that has significantly increased the life expectancy of people.

For the study, the researchers looked at the prevalence of Type-1 diabetes in 118 countries and changes in life expectancy from 1950 to 2010.

After applying a measure known as the Biological State Index to the data, they found that the rapid increase in Type-1 diabetes over the last few decades was directly linked with increases in human life expectancy, especially in Western countries.

"Up to the early 20th century, Type-1 diabetes was a horrible and dangerous disease, usually leading to people's death during their teens or early 20s," said lead study author Wenpeng You.

"This meant there was limited opportunity for people with the disease to have children and to pass their genetic material onto future generations. In evolutionary terms, this is what we call 'natural selection',” he explained.

However, with the widespread introduction of insulin from the 1920s onwards, and improvements in modern medicine, life expectancy for people with Type- diabetes has now increased to about 69 years.

"That is a remarkable achievement, but it also means that with reduced natural selection, the genetic material leading to the development of type-1 diabetes may be accumulating at a rapid rate within the world's population," You noted.

The findings were published in the journal BMJ Open Diabetes Research & Care.

The researchers decided to investigate the link because although cases of Type-1 diabetes have been increasing globally, its prevalence is uneven in different parts of the world.

"Not every country has access to good health care, or freely available insulin. In a number of poor countries, such as in Africa, the life expectancy for people with Type-1 diabetes is much lower than in the Western world. This means more people are dying prematurely, with less opportunity to produce offspring who will carry those genes from generation to generation," You said.​

​London, May 10 (IANS) An international team of astrophysicists has detected an intense wind from one of the closest known black holes to the Earth.

The team led by professor Phil Charles from the University of Southampton observed "V404 Cygni" which went into a bright and violent outburst in June 2015 after more than 25 years of quiescence.

They began taking optical measurements of the black hole's accretion disc using the Gran Telescopio CANARIAS (GTC) - the biggest optical-infrared telescope in the world in the Canary Islands.

The results show the presence of a wind of neutral material (unionised hydrogen and helium), which is formed in the outer layers of the accretion disc, regulating the accretion of material by the black hole.

This wind, detected for the first time in a system of this type, has a very high velocity (3,000 kms per second) so that it can escape from the gravitational field around the black hole.

“Its presence allows us to explain why the outburst, in spite of being bright and very violent, with continuous changes in luminosity and ejections of mass in the form of jets, was also very brief, lasting only two weeks,” explained professor Charles.

“V404 Cygni” is a black hole within a binary system located in the constellation of Cygnus. At only 8,000 light years away, it is one of the closest known black holes to the Earth and has a particularly large accretion disc (with a radius of about 10 million kms), making its outbursts especially bright at all wavelengths (X-rays, visible, infrared and radio waves).

The observations also revealed the presence of a nebula formed from material expelled by the wind.

This phenomenon, which has been observed for the first time in a black hole, also allows scientists to estimate the quantity of mass ejected into the interstellar medium.

“This outburst of 'V404 Cygni' will help us understand how black holes swallow material via their accretion discs,” noted Teo Muñoz Darias, researcher at the Instituto de Astrofísica de Canarias (IAC) in a paper published in the journal Nature.​

New York, May 10 (IANS) An experimental malaria vaccine has been found to protect a small number of healthy people from infection for more than one year after immunisation, says a study.

The vaccine, known as the PfSPZ Vaccine, was developed and produced by US-based biotechnology firm Sanaria.

"It is now clear that administering the PfSPZ Vaccine intravenously confers long-term, sterile protection in a small number of participants, which has not been achieved with other current vaccine approaches," said principal investigator of the trial Robert Seder from National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health.

NIAID researchers and collaborators at the University of Maryland School of Medicine in Baltimore conducted the clinical evaluation of the vaccine, which involved immunisation and exposing willing healthy adults to the malaria-causing parasite Plasmodium falciparum (P. falciparum) in a controlled setting.

The parasites that cause malaria are transmitted to humans through the bite of an infected mosquito. 

The PfSPZ Vaccine is composed of live, but weakened P. falciparum sporozoites -- the early developmental form of the parasite.

Previous research showed the PfSPZ Vaccine to be highly protective three weeks after immunisation. In this trial, researchers assessed if protection could last for five months to a year.

For the phase one clinical trial, the researchers enrolled 101 healthy adults aged 18 to 45 years who had never had malaria. 

Of these volunteers, 59 received the vaccine and 32 participants served as controls and were not vaccinated. 

Vaccine recipients were divided into several groups to assess the roles of the route of administration, dose, and number of immunisations in conferring short- and long-term protection against malaria.

To evaluate how well the vaccine prevented malaria infection, all participants - including the control participants who were not vaccinated - were exposed at varying times to the bites of mosquitoes carrying the same P. falciparum strain from which the vaccine was derived. 

The researchers found that the vaccine provided malaria protection for more than one year in 55 percent of people without prior malaria infection. 

The findings were published in the journal Nature Medicine.

In those individuals, the vaccine appeared to confer sterile protection, meaning the individuals would be protected against disease and could not further transmit malaria. 

The vaccinations were also well-tolerated among participants, and there were no serious adverse events attributed to vaccination, said the study.​