Knowledge Update

​New York, Oct 4 (IANS) Driven by burning of fossil fuels, which consumes oxygen and produces carbon dioxide, the rate of oxygen decline from the Earth's atmosphere has speeded up over the past 100 years, says a study.

Researchers from Princeton University compiled 30 years of data to construct the first ice core-based record of atmospheric oxygen concentrations spanning the past 800,000 years, according to the paper published in the journal Science.

The record showed that atmospheric oxygen has declined 0.7 per cent relative to current atmospheric-oxygen concentrations, a reasonable pace by geological standards, the researchers said. 

During the past 100 years, however, atmospheric oxygen has declined by a comparatively speedy 0.10 per cent because of the burning of fossil fuels, which consumes oxygen and produces carbon dioxide.

"This record represents an important benchmark for the study of the history of atmospheric oxygen," said Assistant Professor of Geosciences John Higgins.

"Understanding the history of oxygen in Earth's atmosphere is intimately connected to understanding the evolution of complex life," Higgins noted.

Curiously, the decline in atmospheric oxygen over the past 800,000 years was not accompanied by any significant increase in the average amount of carbon dioxide in the atmosphere, though carbon dioxide concentrations do vary over individual ice age cycles. 

To explain this apparent paradox, the researchers called upon a theory for how the global carbon cycle, atmospheric carbon dioxide and the Earth's temperature are linked on geologic timescales.

"The planet has various processes that can keep carbon dioxide levels in check," said first author Daniel Stolper.

The researchers discussed a process known as "silicate weathering" in particular, wherein carbon dioxide reacts with exposed rock to produce, eventually, calcium carbonate minerals, which trap carbon dioxide in a solid form. 

As temperatures rise due to higher carbon dioxide in the atmosphere, silicate-weathering rates are hypothesised to increase and remove carbon dioxide from the atmosphere faster.

The study suggests that the extra carbon dioxide emitted due to declining oxygen concentrations in the atmosphere stimulated silicate weathering, which stabilised carbon dioxide but allowed oxygen to continue to decline.

"The Earth can take care of extra carbon dioxide when it has hundreds of thousands or millions of years to get its act together. In contrast, humankind is releasing carbon dioxide today so quickly that silicate weathering can't possibly respond fast enough," Higgins noted.

"The Earth has these long processes that humankind has short-circuited," Higgins said.

The researchers built their history of atmospheric oxygen using measured ratios of oxygen-to-nitrogen found in air trapped in Antarctic ice. This method was established by co-author Michael Bender.

​New York, Oct 4 (IANS) Electrifying brain circuits could treat neurological and psychiatric symptoms not because it causes neurons to fire but it creates an environment that makes it more or less likely for neurons to fire, researchers, including one of Indian-origin, have found.

Rather than taking medication, a growing number of people who suffer from chronic pain, epilepsy and drug cravings are zapping their skulls -- using transcranial direct current stimulation (tDCS) -- in the hope that a weak electric current will jolt them back to health.

"Although this therapy is taking off at the grassroots level and in academia (with an exponential increase in publications), evidence that tDCS does what is being promised is not conclusive," said the study's senior author Danny J.J. Wang, Professor of neurology at Mark and Mary Stevens Neuroimaging and Informatics Institute, University of Southern California in the US.

In this study, published in the journal Scientific Reports, the researchers developed an MRI method whereby the magnetic fields induced by tDCS currents can be visualised in living humans

"Scientists don't yet understand the mechanisms at work, which prevents the FDA from regulating the therapy. Our study is the first step to experimentally map the tDCS currents in the brain and to provide solid data so researchers can develop science-based treatment," Wang noted.

People in antiquity used electric fish to zap away headaches, but tDCS, as it is now known, was introduced in 2000, said study lead author Mayank Jog, a graduate student conducting research at the David Geffen School of Medicine at University of California, Los Angeles.

"Since then, this noninvasive, easy-to-use, low-cost technology has been shown to improve cognition as well as treat clinical symptoms," Jog said.

The study is a technological breakthrough, study co-author Maron Bikson, Professor at The City College of New York, noted.

"You cannot characterise what you cannot see, so this is a pivotal step in the development of tDCS technology," Bikson said.

The researchers validated their MRI algorithm with a phantom, where the current path and induced magnetic field was known. 

Then they tested the method using simple biological tissue -- a human calf. Finally, they repeated the process on the scalp of 12 healthy volunteers.

After 20 to 30 minutes in a scanner, the new algorithm produced an image of the magnetic field tDCS created. 

​New York, Oct 4 (IANS) Researchers have developed a new technology that could allow non-invasive testing of glucose levels, via a contact lens that samples glucose levels in tears.

Current method to monitor glucose levels involve a medication process along with a painful fingerpick blood test.

Glucose is a good target for optical sensing, and can be used as an alternative approach, the study said. 

"It should be noted that glucose is present not only in the blood but also in tears, and thus accurate monitoring of the glucose level in human tears by employing a contact-lens-type sensor can be an alternative approach for non-invasive glucose monitoring," said Wei-Chuan Shih, Associate Professor at University of Houston in Texas, US. 

The researchers developed a tiny device built with multiple layers of gold nanowires and gold film that was produced, using solvent assisted nanotransfer printing.

This component strengthens a technique called surface-enhanced Raman scattering -- named after Indian physicist C.V. Raman, who discovered the effect first in 1928 -- which gauges how light interacts with a material to determine its molecular composition, the researchers stated.

Further, the device enhances the sensing properties of the technique by creating "hot spots" or narrow gaps within the nanostructure which intensified the Raman signal.

Traditional nanofabrication techniques rely on a hard substrate -- usually glass or a silicon wafer -- but researchers wanted a flexible nanostructure which would be more suited to wearable electronics, Shih said. 

The layered nanoarray was produced on a hard substrate but lifted off and printed onto a soft contact, Shih said in the paper published in the journal Advanced Materials.

Although non-invasive glucose sensing is just one potential application of the technology, it provided a good way to prove the technology, he said. 

Moreover, the device is also an effective mechanism for using surface-enhanced Raman scattering spectroscopy.

New York, Oct 4 (IANS) Love to drink that sweetened soda, or other sugar-laden fruit juices, sports drinks, energy drinks? Beware, as you can be at an increased risk of developing various cancers, a study has found.

"Recently growing evidence suggests a link between sugar-sweetened beverage consumption and the risk of pancreatic and endometrial cancer, as well as the risk of colon cancer recurrence and death among cancer survivors," said Melinda Sothern, Professor at Louisiana State University Health Sciences in New Orleans, US.

Additionally, such individuals may also be at risk of developing health issues like obesity, diabetes and cardio-metabolic diseases.

As more people are surviving cancer, the consumption of added sugar will be an increasingly important risk factor.

The American Heart Association recommends a consumption goal of no more than 450 kilocalories (kcal) of sugar-sweetened beverages or fewer than three 12-ounce cans of soda per week, the researchers said.

"Although consuming added sugar is not recommended, people are not usually aware of how much sugar they get from sugar-sweetened beverages," said lead author Tung-Sung Tseng, Associate Professor of Public Health at LSU Health New Orleans. 

The results of the study indicate that sugar-sweetened beverage consumption behaviour varies across cancers and may be related to age. 

Intervention programs to reduce consumption of added sugar be focused on lower socio-economic status, young males, as well as cervical cancer survivors, the researchers suggested. 

They also recommend that custom intervention to decrease added sugar consumption be conducted for both non-cancer individuals and cancer survivors in communities and the medical care system.

For the study, the team examined data from 22,182 adults from the National Health and Nutrition Examination Survey (NHANES) 2003-2012 data. 

The survey measured the consumption of sodas, fruit-flavoured drinks, sweetened fruit juices, sports drinks, energy drinks, sweetened teas and coffees and other sugar-sweetened drinks. 

It also ascertained cancer, smoking and obesity status, as well as demographic characteristics including age, gender, race, educational level and poverty/income ratio.

For the overall study population, 15.7 per cent had high sugar intake from sugar-sweetened drinks. People with no cancer history had a higher sugar intake than cancer survivors, although this could be due to other factors including older age and gender. 

The sugar intake from sugar-sweetened beverages among women with cervical cancer history was much higher (60g/day) compared to other cancer survivors who consumed only around 30-40 g/day. 

The research team also found that individuals who had high sugar intake (80g/day sugar) from sugar-sweetened beverages were younger, male, black, obese, current smokers, low-income, or had education levels at or below high school.

The study is published in the journal of Translational Cancer Research.

Sweden, Oct 4 (IANS) British trio -- David J. Thouless, F. Duncan M. Haldane and J. Michael Kosterlitz -- on Tuesday won Nobel Prize in Physics "for theoretical discoveries of topological phase transitions and topological phases of matter".

The Royal Swedish Academy of Sciences decided to award the prize to Thouless from the University of Washington in Seattle, Haldane from the Princeton University in New Jersey, US, and Kosterlitz from the Brown University in New Jersey as they have used "advanced mathematical methods to study unusual phases, or states, of matter, such as superconductors, superfluids or thin magnetic films".

It is because of their pioneering work that the hunt is now on for new and exotic phases of matter. Many people are hopeful of future applications in both materials science and electronics, said a statement at the official website of the Nobel Prize.

New York, Oct 5 (IANS) Medication-resistant bacteria are making it more difficult to treat a common but severe kidney infection, says a study.

Pyelonephritis -- infection of the kidney usually caused by E. coli bacteria and which can start as a urinary tract infection -- causes fever, back pain and vomiting. 

About half of people infected require hospitalisation. If not treated with effective antibiotics, it can cause sepsis and death.

"This is a very real example of the threat posed by the emergence of new antibiotic-resistant strains of bacteria, which greatly complicates treatment of infection," said the study's lead author David Talan, Professor at David Geffen School of Medicine at University of California, Los Angeles. 

In an earlier study based on data from 10 large hospital emergency departments in the US, almost 12 per cent of people diagnosed with pyelonephritis had infections resistant to the standard class of antibiotic used in treatment -- fluoroquinolone. That is up from four per cent in a similar study conducted a decade ago. 

The new study -- published in the jurnal Emerging Infectious Diseases -- also documents the emergence of infections caused by a specific strain of E. coli that is resistant to additional types of antibiotics, severely limiting treatment options. 

That strain, dubbed ESBL for the antibiotic-destroying enzymes it produces (extended-spectrum beta-lactamases), was not detected in the previous study. 

Currently, there are only a few intravenous antibiotic options to treat ESBL-related infections, and no oral antibiotics that are consistently effective.

The study included 453 people diagnosed with kidney infection. The study participants were diagnosed between July 2013 and December 2014 in 10 emergency departments at large hospitals in the US.

The rates of ESBL-related infections varied from zero per cent to more than 20 per cent, depending on the location of the emergency room and patient risk factors.

About three of every four people infected with ESBL-producing E. coli were initially treated with antibiotics ineffective against that particular strain of bacteria, placing them at risk for poor outcomes, the researchers reported.

Addis Ababa (Ethiopia), Oct 5 (IANS) Horn of Africa countries Ethiopia and Djibouti on Wednesday launched the continent's first modern electric railway connecting their respective capitals, media reported.

The 752.7 km Ethiopia-Djibouti railway was inaugurated in the Ethiopian capital Addis Ababa in a grand ceremony, Xinhua news agency reported.

The railway has a designed speed of 120 km per hour and was constructed by China Railway Group and China Civil Engineering Construction Corporation with a total investment of $4 billion.

It is expected to reduce travel time between the two capital cities from seven days by road to about 10 hours only, and provide landlocked Ethiopia faster access to Djibouti port.

​New York, Oct 5 (IANS) Researchers have crystallised and determined the 3D structure of a protein that could help them develop new treatments by understanding nicotine's molecular effects.

The protein, called alpha-4-beta-2 nicotinic receptor, sits on nerve cells in the brain. Nicotine binds to the receptor when someone smokes a cigarette or chews tobacco, causing the protein to open a path for ions to enter the cell. 

The process produces cognitive benefits such as increased memory and focus but is also highly addictive.

Until the new findings were reported in the journal Nature, scientists did not have a way to examine at atomic resolution how nicotine achieves these addictive effects.

"It's going to require a huge team of people and a pharmaceutical company to study the protein and develop the drugs, but I think this is the first major stepping stone to making that happen," said study co-author Ryan Hibbs, Assistant Professor at the Peter O'Donnell Jr. Brain Institute at University of Texas Southwestern Medical Center in the US.

The expectation is that the 3D structures will help researchers understand how nicotine influences the activity of the receptor and lead to a medication that mimics its actions in the brain.

The finding may also have benefits in creating medications for certain types of epilepsy, mental illness, and dementia such as Alzheimer's, which are also associated with the nicotinic receptor, the researchers said. 

However, testing of any ensuing treatment would likely take many years, Hibbs cautioned.

Studies have shown smoking cessation drugs have mixed results in treating nicotine addiction, as have other methods such as nicotine patches and chewing gum.

​London, Oct 5 (IANS) A handgrip could be used for early detection of health problems that may lead to premature death, say researchers.

Handgrip strength is a simple test, measured with a hand-held device. On average, handgrip strength peaks in the 30s and 40s and then declines with age.

"When individuals' handgrip falls below some reference value for their age group, sex and body height this can be taken as an indicator for practitioners that further health checks may be warranted," said Nadia Steiber from International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria.

"The measurement of handgrip strength in clinical practice is a simple but efficient screening tool for health vulnerability. It comes at a very low cost," Steiber noted.

The study builds on research conducted as part of the Reassessing Aging from a Population Perspective (Re-Aging) project, which showed that handgrip strength could be used as an alternative measure for age, since it corresponds with other markers of age such as future mortality, disability, cognitive decline and ability to recover from hospital stays.

The new study, published in the journal PLOS ONE, provides a comprehensive set of reference values for the measurement of handgrip strength that could be used in clinical practice. 

The study was based on data from the German Institute for Economic Research including over 25,000 measurements of over 11,000 people.