Knowledge Update

​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.​

Washington, May 10 (IANS) Presence of warm water in the Pacific Ocean due to a stalled El Nino in 2014 stacked the deck for a monstrous version of the warming climate cycle to occur in 2015, a study says.

Easterly winds in the tropical Pacific Ocean stalled a potential El Nino in 2014 and left a swath of warm water in the central Pacific. This left over warm water gave the current El Nino a head start, the researchers explained.

El Nino and La Nina are the warm and cool phases of a recurring climate pattern across the tropical Pacific Ocean called the El Nino-Southern Oscillation, or ENSO. 

The warm and cool phases shift back and forth every two to seven years, and each phase triggers predictable disruptions in temperature, wind, and rain across the globe. 

During El Nino events, water temperatures at the sea surface are higher than normal. Low-level surface winds, which normally blow east to west along the equator, or easterly winds, start blowing the other direction, west to east, or westerly.

In the spring of 2014, strong westerly winds near the equator in the western and central Pacific Ocean created a buzz among scientists - they saw the winds as a sign of a large El Nino event to come in the winter of 2014, said lead author of the study Aaron Levine, a climate scientist at US National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory in Seattle, Washington.

But as the summer progressed, El Niño did not form the way scientists expected it to. Sea surface temperatures in the eastern Pacific never warmed enough to truly be called an El Nino, and the buzz fizzled out.

But then, in the spring of 2015, episodes of very strong westerly wind bursts occurred and became more frequent throughout the summer. 

Following a pattern set by previous large El Ninos, 2015 to 2016 became one of the three strongest El Ninos on record, along with 1982 to 1983 and 1997 to 1998, Levine said.

The findings will be published in a forthcoming issue of the journal Geophysical Research Letters.

​Washington, May 10 (IANS) Turning the traditional knowledge on its head that young Earth had a thicker atmosphere, scientists, including an Indian-origin researcher, have found that air at that time exerted at most half the pressure of today's atmosphere.

The new finding reverses the commonly accepted idea that the early Earth had a thicker atmosphere to compensate for weaker sunlight.

The finding also has implications for which gases were in that atmosphere and how biology and climate worked on the early planet.

"For the longest time, people have been thinking the atmospheric pressure might have been higher back then, because the sun was fainter," said lead author Sanjoy Som, who did the work as part of his doctorate in earth and space sciences at University of Washington.

The team used bubbles trapped in 2.7 billion-year-old rocks to reach this conclusion.

"Our result is the opposite of what we were expecting," he added in a paper published in the journal Nature Geoscience.
Som is currently doing astrobiology research at NASA's Ames Research Centre in California.

The idea of using bubbles trapped in cooling lava as a "paleobarometer" to determine the weight of air in our planet's youth occurred decades ago to co-author Roger Buick, professor of earth and space sciences.

A potential site in western Australia was discovered by co-author Tim Blake of University of western Australia.

There, the Beasley River has exposed 2.7 billion-year-old basalt lava.

A stream of molten rock quickly cools from top and bottom, and bubbles trapped at the bottom are smaller than those at the top.

The size difference records the air pressure pushing down on the lava as it cooled, 2.7 billion years ago.

Rough measurements in the field suggested a surprisingly lightweight atmosphere.

More rigorous x-ray scans from several lava flows confirmed the result: The bubbles indicate that the atmospheric pressure at that time was less than half of today's.

Earth 2.7 billion years ago was home only to single-celled microbes, sunlight was about one-fifth weaker and the atmosphere contained no oxygen.

But this finding points to conditions being even more otherworldly than previously thought.

A lighter atmosphere could affect wind strength and other climate patterns and would even alter the boiling point of liquids.

Other geological evidence clearly shows liquid water on Earth at that time so the early atmosphere must have contained more heat-trapping greenhouse gases like methane and carbon dioxide and less nitrogen.

The result also reinforces Buick's 2015 finding that microbes were pulling nitrogen out of Earth's atmosphere some three billion years ago.

"People will need to rewrite the textbooks," the authors noted.

The researchers will now look for other suitable rocks to confirm the findings and learn how atmospheric pressure might have varied through time.​

London, May 10 (IANS) In a finding that could change the way the most common form of stroke is treated globally, researchers have shown that modified dosage of a clot-busting drug can reduce risk of serious bleeding in the brain and improve survival rates.

Intravenous rtPA (or alteplase) is given to people suffering acute ischaemic stroke and works by breaking up clots blocking the flow of blood to the brain.

However, it can cause serious bleeding in the brain in around five per cent of cases, with many of these proving fatal.

Compared to standard dose (0.9mg/kg body weight), the lower dose (0.6mg/kg) of rtPA reduced rates of serious bleeding in the brain, known as intracerebral haemorrhage (ICH), by two thirds, showed the results of the trial of more than 3,000 patients in 100 hospitals worldwide.

"Most patients who have a major stroke want to know they will survive but without being seriously dependent on their family. We have shown this to be the case with the lower dose of the drug,” said one of the researchers Tom Robinson, professor at University of Leicester in Britain.

The findings were published in the New England Journal of Medicine.

"At the moment you could have a stroke but end up dying from a bleed in the brain. It's largely unpredictable as to who will respond and who is at risk with rtPA,” lead author of the study Craig Anderson, professor at Sydney Medical School, University of Sydney in Australia.

"What we have shown is that if we reduce the dose level, we maintain most of the clot busting benefits of the higher dose but with significantly less major bleeds and improved survival rates. On a global scale, this approach could save the lives of many tens of thousands of people,” Anderson noted.​

​New York, May 6 (IANS) Although India managed to counter a steep decline in its vulture population in mid-1990s, these efficient scavengers are in danger of disappearing in many parts of the world primarily due to the presence of toxins in the carrion they consume.

Poisoning is the greatest extinction risk facing vultures, and impacts 88 percent of threatened vulture species, the study said.

Now, the center of the vulture crisis is in sub-Saharan Africa, the researchers noted.

In the mid-1990s India experienced a precipitous vulture decline, with more than 95 percent of vultures disappearing by the early 2000s. 

"That was a massive collapse that led a lot of people to really focus more attention on vultures," said one of the researchers Evan Buechley from University of Utah in the US.

The cause was eventually traced to diclofenac, a veterinary anti-inflammatory drug that relieved pain in cattle, but proved highly toxic to vultures. 

Hundreds of vultures would flock to each cattle carcass. And if the cow had recently been treated with diclofenac, hundreds of vultures would die. 

Because of this highly gregarious feeding behaviour, less than one percent of cattle carcasses contaminated with diclofenac could account for the steep vulture decline. 

Fortunately, international cooperation led to a total ban on veterinary diclofenac use. 

The numbers of vultures have stabilised, and are now showing signs of slowly increasing, Buechley said.

Losses of vultures can allow other scavengers to flourish, Buechley pointed out in a report published in the journa Biological Conservation.

For example, following the decline of vultures, India experienced a strong uptick in feral dogs --by an estimated seven million. 

The increase in dogs, potentially feeding on disease-ridden carcasses, is thought to have at least partially caused the rabies outbreak that was estimated to have killed 48,000 people from 1992-2006 in India -- deaths that may have been avoided if not for the disappearance of vultures.

Members of the Parsi sect of Zoroastrianism experienced a different impact. For thousands of years, the Parsi people have placed their dead on exposed mountaintops or tall towers for vultures to consume. The practice is called "sky burial."

But with few vultures and unable to properly handle their dead, the Parsis experienced a crisis within the faith. ​

Some constructed captive vulture aviaries. Others talked about desiccating bodies using focused solar mirrors. The Parsis' plight exemplifies the vultures' role in south Asian society -- and the various impacts if the vultures are not there.

Although the vulture crisis in Africa is ongoing, the researchers can predict what the outcome will be, based on previous experiences in India. 

Crows, gulls, rats and dogs will boom. And the rabies outbreak in India may just be a prologue, because several sub-Saharan Africa countries already have the highest per-capita rabies infection rates in the world, the researchers noted.