Knowledge Update

​London, Dec 25 (IANS) Using ultrafast imaging of moving energy, scientists have determined the speed of photosynthesis.

The study said the imaging could help scientists better understand the process and how it could be copied for producing fuels.

Earlier, it was believed that the process of charge separation in the reaction was the slowest step in the process. But scientists have shown that the slowest step is in fact the process through which the plants harvest light and transfer its energy through the antennae to the reaction centre.

"We can now see how nature has optimised the physics of converting light energy to fuel, and can probe this process using our new technique of ultrafast crystal measurements," said Jasper van Thor from Imperial College, London.

"For example, is it important that the bottleneck occurs at this stage, in order to preserve overall efficiency? Can we mimic it or tune it to make artificial photosynthesis more efficient? These questions, and many others, can now be explored," Thor added.

Scientists used lasers to cause reactions in crystals of Photosystem II -- enzyme that uses the light energy to split water into oxygen and hydrogen -- and then measured in space and time the movement of excitations of electrons.

"The resulting movie of the movement of excited electrons across minute sections of the system revealed where energy is held and when it is passed along," the study noted.

The study was published in the journal Nature Communications.

​New York, Dec 25 (IANS) When exposed to cancer treatment like chemotherapy and radiation, brain and heart tissues in very young children are more prone to apoptosis or programmed cell death, researchers said.

Apoptosis, in which molecular signals order cells to self-destruct, plays an important role in deciding the "fate" of a developing cell.

These toxic treatment stressors put young children at high risk for developing severe, long-lasting impairments in their brain, heart, the study said.

But active apoptosis in the early brain "also sets the stage for extremely high sensitivity to any type of damage or stress, especially that induced by radiation or chemotherapy," said lead author Kristopher A. Sarosiek, Assistant Professor at the Harvard T.H. Chan School of Public Health.

While some cancer cells die through apoptosis, some escape the death orders by activating "pro-survival" signals.

Anthony Letai from Dana-Farber Cancer Institute in Massachusetts, developed a test called BH3 profiling that can measure inside any cell the relative dominance of pro-survival or pro-death signals.

A cancer cell in which apoptotic death signals are dominant, is said to be "highly primed" or ready for self-destruction and therefore easily killed by therapy, while a cell with low priming is more resistant to death or damage.

Measuring the priming of cells in normal cells and tissues, the researchers found that in most normal adult tissues, including the brain and the heart, the machinery needed to perform apoptosis is nearly completely absent.

In contrast, this molecular machinery is abundant in newborn and very young rodents. As a result, brain and heart cells were therefore much more vulnerable to undergoing cell death when exposed to chemotherapy or radiation.

When tested in human cells, the youngest human brain cells were more highly primed with apoptotic machinery and vulnerable to chemotherapy and radiation damage.

Human brain and heart cells are most highly primed for apoptosis until four to six years of age, after which priming continues to be reduced, the researchers noted, in the paper appearing in the journal Cancer Cell.

New York, Dec 25 (IANS) Driverless cars can save fuel if they trail each other in large platoons, as they will experience less aerodynamic drag when they drive close together, researchers have found.

But formation of a vehicle platoon could be time consuming.

The study by the researchers at Massachusetts Institute of Technology (MIT) that was recently presented at the International Workshop on the Algorithmic Foundations of Robotics suggested that relatively simple, straightforward schedules may be the optimal approach for saving fuel and minimising delays for autonomous vehicle fleets.

The findings may also apply to conventional long-distance trucking and even ride-sharing services.

"Ride-sharing and truck platooning and even flocking birds and formation flight, are similar problems from a systems point of view," said Sertac Karaman, Associate Professor at MIT.

"People who study these systems only look at efficiency metrics like delay and throughput. We look at those same metrics, versus sustainability such as cost, energy, and environmental impact. This line of research might really turn transportation on its head," Karaman added.

The research noted that for truck-driving -- particularly over long distances -- most of a truck's fuel is spent on trying to overcome aerodynamic drag, that is, to push the truck through the surrounding air.

"Scientists have previously calculated that if several trucks were to drive just a few metres apart, one behind the other, those in the middle should experience less drag, saving fuel by as much as 20 per cent, while the last truck should save 15 per cent -- slightly less, due to air currents that drag behind," the study found.

As the number of vehicles are increased in the platoon, more energy can be collectively saved but it may cost in terms of time it takes to form a platoon.

The study found that the simplest policies resulted in least delays in platoon formation while saving most fuel.

"Time tables set to deploy platoons at regular intervals were more sustainable and efficient than those that deployed at more staggered times," the study mentioned.

​New York, Dec 24 (IANS) Studying a diverse group of solitary, desert bees, researchers have reported identification of nine new species of the genus Perdita, including two ant-like males.

These solitary bees are not major pollinators of agricultural crops, but fill an important role in natural ecosystems of the American Southwest, including the sizzling sand dunes of California's Death Valley.

In a study published in the journal Zootaxa, the researchers described curious ant-like males of two of the species, which are completely different in appearance from their mates.

"It's unclear why these males have this unique form, but it could indicate they spend a lot of time in the nest," said entomologist Zach Portman from Utah State University in the US.

"We may find more information as we learn more about their nesting biology," Portman noted.

Portman tracked the tiny elusive bees by watching for their buzzing shadows in the blinding, midday sunlight the diminutive insects tend to favour.

"Their activity during the hottest part of the day may be a way of avoiding predators," Portman said.

"They appear to be important pollinators of desert plants commonly known as 'Crinklemats'" Portman explained.

Crinklemats, flowering plants of the genus Tiquilia, grow low to the ground and feature ridged, hairy leaves and small, trumpet-shaped blue blossoms.

"Like the bees, Tiquilia flowers are very small," Portman said. 

"The bees must squeeze into the long, narrow corollas and dunk their heads into the flowers to extract the pollen," he added.

The scientists reported that the female bees use pollen collected from the flowers to build up a supply to nourish their young. 

Once they have completed a pollen provision, the bees lay their eggs on the stash and leave their offspring to fend for themselves.

Though declines in bee populations have heightened awareness of the importance of pollinating insects to the world's food supply, numerous bee species remain undescribed or poorly understood, the researchers pointed out.

New York, Dec 24 (IANS) Researchers have found that centuries-old herbal medicine, discovered by Chinese scientists to treat malaria, can aid in tuberculosis (TB) treatment and even slow drug resistance.

One-third of the world's population is infected with TB, which killed 1.8 million people in 2015, according to the Centers for Disease Control and Prevention.

Mycobacterium tuberculosis (Mtb) -- the TB-causing bacteria -- needs oxygen to thrive in the body and the immune system starves this bacterium of oxygen to control the infection. 

The study found that artemisinin -- the ancient remedy -- stopped the ability Mtb to become dormant -- a stage of the disease that often makes the use of antibiotics ineffective.

"When TB bacteria are dormant, they become highly tolerant to antibiotics. Blocking dormancy makes the TB bacteria more sensitive to these drugs and could shorten treatment times," said Robert Abramovitch, Assistant Professor at Michigan State University in the US.

Artemisinin attacks a molecule called heme, which is found in the Mtb oxygen sensor. 

By disrupting this sensor and essentially turning it off, the medicine stopped the disease's ability to sense how much oxygen it was getting, the researchers said.

"When the Mtb is starved of oxygen, it goes into a dormant state, which protects it from the stress of low-oxygen environments. If Mtb can't sense low oxygen, then it can't become dormant and will die," Abramovitch said. 

TB takes up to six months to treat and is one of the main reasons the disease is so difficult to control, the researchers said.

They also said that the finding could be key to shortening the course of therapy because it can clear out the dormant, hard-to-kill bacteria.

The paper was published in the journal Nature Chemical Biology.

​London, Dec 24 (IANS) Our decision-making is heavily influenced by the world around us, a study has found, challenging the traditional idea that thinking takes place strictly in the head.

The idea that thinking is done only in the head is a convenient illusion that doesn't reflect how problems are solved in reality, said Gaelle Vallee-Tourangeau, Professor at Kingston University in Britain.

"When you write or draw, the action itself makes you think differently. In cognitive psychology you are trained to see the mind as a computer, but we've found that people don't think that way in the real world. 

"If you give them something to interact with they think in a different way," Vallee-Tourangeau added.

In the study, the researchers explored how maths anxiety -- a debilitating emotional reaction to mental arithmetic that can lead sufferers to avoid even simple tasks like splitting a restaurant bill -- could potentially be managed through interactivity.

The study involved asking people to speak a word repeatedly while doing long sums at the same time. 

The results showed that the mathematical ability of those asked to do the sums in their heads was more affected than those given number tokens that they could move with their hands.

"We found that for those adding the sums in their head, their maths anxiety score predicted the magnitude of errors made while speaking a word repeatedly. If they're really maths anxious, the impact will be huge," Vallée-Tourangeau explained. 

"But in a high interactivity context -- when they were moving number tokens -- they behaved as if they were not anxious about numbers," Vallée-Tourangeau said.

Understanding how we think and make decisions by interacting with the world around us could help businesses find new ways of improving productivity -- and even improve people's chances of getting a job, the researches noted.

The study was published in the journal Cognitive Research: Principles and Implications.

​New York, Dec 24 (IANS) Researchers have developed a new test that can identify hearing loss or deficits in some individuals considered to have normal or near-normal hearing in traditional tests.

Many adults report difficulties hearing in everyday situations, despite having their physicians or audiologists tell them that the results of their hearing tests are normal or near-normal.

"We now have a validated technique to identify 'hidden' hearing deficits that would likely go undetected with traditional audiograms," said Leslie Bernstein, Professor at University of Connecticut School of Medicine in the US.

Their newly developed hearing test measures a person's ability to detect across-ears (binaural) changes in sounds presented at levels of loudness that are close to those experienced in normal conversations.

The binaural system plays a fundamental and predominant role in the ability to localise sounds, to understand conversation in places such as busy restaurants, and to attend to one of multiple, simultaneous sounds.

The researchers studied 31 adults between ages 30 to 67 with normal or near-normal audiograms.

The results of the study published in the Journal of the Acoustic Society of America showed that listeners who have essentially normal clinical hearing test results may exhibit substantial deficits in binaural processing. 

"Our study shows that our novel binaural hearing test can help early identify vulnerable populations of listeners, and perhaps help determine when critical interventions are warranted," Constantine Trahiotis, Emeritus Professor at University of Connecticut School of Medicine, noted.

Acquired hearing loss from excessive noise exposure has long been known to produce significant, and sometimes debilitating, hearing deficits, Bernstein pointed out.

The new research suggests that hearing loss may be even more widespread than was once thought.

New York, Dec 24 (IANS) If you closely followed the recently concluded US presidential election, you might have already realised what a new study confirms - providing contradictory evidence to change one's political beliefs may actually backfire.

People become more hard-headed in their political beliefs when provided with counter-evidence because the brain may perceive the challenges to political beliefs in the same way it perceives threat and anxiety, the study suggests.

"Political beliefs are like religious beliefs in the respect that both are part of who you are and important for the social circle to which you belong," said lead author Jonas Kaplan from University of Southern California in the US.

"To consider an alternative view, you would have to consider an alternative version of yourself," Kaplan said.

To determine which brain networks respond when someone holds firmly to a belief, the neuroscientists compared whether and how much people change their minds on nonpolitical and political issues when provided counter-evidence.

They discovered that people were more flexible when asked to consider the strength of their belief in nonpolitical statements -- for example, "Albert Einstein was the greatest physicist of the 20th century".

But when it came to reconsidering their political beliefs, such as whether the US should reduce funding for the military, they would not budge.

"I was surprised that people would doubt that Einstein was a great physicist, but this study showed that there are certain realms where we retain flexibility in our beliefs," Kaplan said.

For the study, the neuroscientists recruited 40 people who were self-declared liberals. 

The scientists then examined through functional MRI how their brains responded when their beliefs were challenged.

The study - published in the journal Scientific Reports - found that people who were most resistant to changing their beliefs had more activity in the amygdalae (a pair of almond-shaped areas near the center of the brain) and the insular cortex, compared with people who were more willing to change their minds.

"The activity in these areas, which are important for emotion and decision-making, may relate to how we feel when we encounter evidence against our beliefs," Kaplan said.

"The amygdala in particular is known to be especially involved in perceiving threat and anxiety," Kaplan added. 

"The insular cortex processes feelings from the body, and it is important for detecting the emotional salience of stimuli. That is consistent with the idea that when we feel threatened, anxious or emotional, then we are less likely to change our minds," Kaplan explained.

He also noted that a system in the brain, the Default Mode Network, surged in activity when participants' political beliefs were challenged.

"These areas of the brain have been linked to thinking about who we are, and with the kind of rumination or deep thinking that takes us away from the here and now," Kaplan said.

​New York, Dec 23 (IANS) Children born to women who smoked during their pregnancy were more likely to show signs of kidney damage by the age of three, compared to those born to non-smoking mothers, a research has warned.

The study showed that maternal smoking during pregnancy was one of the risk factors of childhood proteinuria -- abnormal amount of protein in urine -- a sign of kidney disease.

The effects on kidney health were evident in 3-year-old children.

"Maternal smoking during pregnancy is known to be associated with preterm birth, low birth weight, and neonatal asphyxia. The findings from this study suggest an additional adverse effects of maternal smoking during pregnancy," said Koji Kawakami from Kyoto University, in Japan. 

For the study, the team looked for the presence of proteinuria in urinary tests from 44,595 children from pregnancy to three-years of age. 

The results showed that the prevalence rates of proteinuria in children at age three in the maternal smoking groups -- none, past, and current -- were 78.9 per cent, 4.4 per cent and 16.7 per cent, respectively. 

Maternal smoking during pregnancy was associated with a 1.24-times increased risk of child proteinuria compared with no exposure to maternal smoking during pregnancy.

"Prevention of child proteinuria is important since child proteinuria can lead to development of chronic kidney disease in adulthood and ultimately end stage renal disease," Kawakami said.

The findings is forthcoming in the Clinical Journal of the American Society of Nephrology (CJASN). 

New York, Dec 23 (IANS) Exposure to a common plastic compound found in baby bottles and personal care products may increase the risk of pregnant women and lactating mothers developing negative behavioural changes and impairment in brain regions, researchers have warned.

The study, conducted in mice, showed that the exposure to bisphenol S (BPS) -- a replacement chemical for Bisphenol A (BPA) -- impaired the maternal care of pups, including mothers' ability to adjust to the needs of their young during early development. 

"BPS affects maternal behaviour as well as maternally relevant neural correlates," said Mary Catanese, doctoral student at the University of Massachusetts - Amherst. 

The effects differ based on dose, postpartum period and generational timing of exposure, Catanese said.

Further, BPS exposure was found to increase the infanticide thoughts in a brain region sensitive to estrogen or estrogen-mimicking chemicals as well as important in maternal behaviour in mice. 

"Although these same effects were not seen at the higher dose, more than 10 per cent of females exposed to two microgram BPS/kg per day either killed their pups or provided such poor instrumental maternal care that one or more pups needed to be euthanised. 

While not statistically significant, the neglect and poor maternal care we observed were striking," explained Laura Vandenberg, assistant professor at the University of Massachusetts.

In addition, BPS exposure may also impair a mother to adjust to the changing needs of her pups, the researchers observed.

BPS-exposed mothers showed significantly shorter latency to retrieve their first pup and significantly shorter latency to retrieve their entire litter, which may not represent improved care but instead "may indicate hyperactivity, compulsivity-like behaviour, heightened stress response to scattered pups, or a displaced form of retrieval," Vandenberg noted.

The details of the study appeared in the journal Endocrinology.