New way to 'fish out' radioactive elements from nuclear waste

March 12, 2017

London, Mar 12: Scientists have found that the most toxic elements from radioactive nuclear waste may be 'fished out' using arsenic molecules - a breakthrough that could make the alternative energy industry safer and more effective. Researchers reported the first examples of thorium with multiple bonds to arsenic to exist under ambient conditions on multi-gram scales where before they had only been prepared on very small scales at temperatures approaching that of interstellar space.

nuclear

"Nuclear power could potentially produce far less carbon dioxide than fossil fuels, but the long-lived waste it produces is radioactive and needs to be handled appropriately," said Elizabeth Wildman, from University of Manchester in the UK. "In order to find ways of separating, recycling and reducing the volume of nuclear waste, research has focused on developing our understanding of how elements like thorium and uranium interact with elements from around the periodic table to potentially help improve nuclear waste clean-up," said Wildman.

"We need to reduce the volume of nuclear waste in order to make it easier to handle and process it to remove benign elements or separate the high level from low level waste," said Professor Steve Liddle, from The University of Manchester. The study looked at how the soft element arsenic interacts with thorium, because arsenic could in principle be used in organic molecules that bond to metal atoms and improve extraction processes.

"There is currently significant interest in using organic molecules to extract, selectively, metal ions from the 'soup' of nuclear waste and fish out the more radioactive and toxic ones and leave the rest behind," Liddle said. "This requires an understanding of chemical bonding and how the organic extractants bind to different metals. We can then exploit this knowledge to achieve separation by having them selectively bind to one type of metal and remove it from the soup," he said.

"There is mounting evidence that the molecules that are best at this contain soft donor atoms to the metals. Thus, we need to understand soft donor-to-metal binding better," he added. "Arsenic is a soft donor, so we have prepared model complexes with it to understand the nature of the bonding," said Liddle.

"Until now, complexes exhibiting multiple bonds between thorium and arsenic were limited to spectroscopic experiments carried out at temperatures close to that of interstellar space (3-10 Kelvin) where only a few molecules were made at a time," he said.

"We have made molecules in multi-gram quantities and they are stable under ambient conditions enabling us to study them more straightforwardly. We might be able to use this new knowledge and understanding in a real system in the future," he added. The finding is published in the journal Nature Communications.

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Agencies
June 27,2020

Mumbai, Jun 27: The Bombay High Court observed that COVID-19 patients from poor and indigent sections cannot be expected to produce documentary proof to avail subsidised or free treatment while getting admitted to hospitals.

The court on Friday was hearing a plea filed by seven residents of a slum rehabilitation building in Bandra, who had been charged ₹ 12.5 lakh by K J Somaiya Hospital for COVID-19 treatment between April 11 and April 28.

The bench of Justices Ramesh Dhanuka and Madhav Jamdar directed the hospital to deposit ₹10 lakh in the court.

The petitioners had borrowed money and managed to pay ₹10 lakh out of ₹12.5 lakh that the hospital had demanded, after threatening to halt their discharge if they failed to clear the bill, counsel Vivek Shukla informed the court.

According to the plea, the petitioners were also overcharged for PPE kits and unused services.

On June 13, the court had directed the state charity commissioner to probe if the hospital had reserved 20% beds for poor and indigent patients and provided free or subsidised treatment to them.

Last week, the joint charity commissioner had informed the court that although the hospital had reserved such beds, it had treated only three poor or indigent persons since the lockdown.

It was unfathomable that the hospital that claimed to have reserved 90 beds for poor and indigent patients had treated only three such persons during the pandemic, advocate Shukla said.

He further argued that COVID-19 patients, who are in distress, cannot be expected to produce income certificate and such documents as proof.

However, senior advocate Janak Dwarkadas, who represented the hospital, said the petitioners did not belong to economically weak or indigent categories and had not produced documents to prove the same.

A person who is suffering from a disease like COVID-19 cannot be expected to produce certificates from a tehsildar or social welfare officer before seeking admission in the hospital, the bench noted and asked the hospital to deposit ₹10 lakh in court within two weeks.

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Agencies
February 6,2020

Washington D.C., Feb 6: An international team of astronomers has found an unusual monster galaxy that existed about 12 billion years ago when the universe was only 1.8 billion years old.

The team of astronomers was led by scientists at the University of California, Riverside.

Dubbed XMM-2599, the galaxy formed stars at a high rate and then died. Why it suddenly stopped forming stars is unclear.

"Even before the universe was 2 billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultra massive galaxy," said Benjamin Forrest, a postdoctoral researcher in the UC Riverside Department of Physics and Astronomy and the study's lead author.

"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than 1 billion years old and then became inactive by the time the universe was only 1.8 billion years old," Forrest added.

The team used spectroscopic observations from the W. M. Keck Observatory's powerful Multi-Object Spectrograph for Infrared Exploration or MOSFIRE, to make detailed measurements of XMM-2599 and precisely quantify its distance.

The study results appear in the Astrophysical Journal.

"In this epoch, very few galaxies have stopped forming stars, and none are as massive as XMM-2599," said Gillian Wilson, a professor of physics and astronomy at UCR in whose lab Forrest works.

"The mere existence of ultramassive galaxies like XMM-2599 proves quite a challenge to numerical models. Even though such massive galaxies are incredibly rare at this epoch, the models do predict them."

"The predicted galaxies, however, are expected to be actively forming stars. What makes XMM-2599 so interesting, unusual, and surprising is that it is no longer forming stars, perhaps because it stopped getting fuel or its black hole began to turn on. Our results call for changes in how models turn off star formation in early galaxies," the professor stated.

The research team found XMM-2599 formed more than 1,000 solar masses a year in stars at its peak of activity -- an extremely high rate of star formation. In contrast, the Milky Way forms about one new star a year.

"XMM-2599 may be a descendant of a population of highly star-forming dusty galaxies in the very early universe that new infrared telescopes have recently discovered," said Danilo Marchesini, an associate professor of astronomy at Tufts University and a co-author on the study.

"We have caught XMM-2599 in its inactive phase," Wilson said, who led the W. M. Keck Observatory data acquisition
Co-author Michael Cooper, a professor of astronomy at UC Irvine, said this outcome is a strong possibility.

"Perhaps during the following 11.7 billion years of cosmic history, XMM-2599 will become the central member of one of the brightest and most massive clusters of galaxies in the local universe," he said.

"Alternatively, it could continue to exist in isolation. Or we could have a scenario that lies between these two outcomes," he stated.

The study was supported by grants from the National Science Foundation and NASA.

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Agencies
February 25,2020

Tokyo, Feb 25: Japan's Chitetsu Watanabe, recognized at 112 years as the oldest man in the world, has passed away 11 days after he received the Guinness World Record certificate, his family said on Tuesday.

Watanabe died on Sunday night, Efe news reported.

He received the official certificate on February 12 at a nursing home in Joetsu in Niigata prefecture, where he resided.

Soon after being certified as the oldest man, he began to experience a lack of appetite and respiratory problems, the wife of his eldest son told public broadcaster NHK.

Born on March 5, 1907 in a family of farmers, Watanabe moved at the age of 20 to Taiwan, where he worked at a sugar refinery for 18 years before returning to Japan after the end of World War II.

A fan of calligraphy, custard and ice cream, Watanabe told the Guinness team that the key to his long life was laughter.

He was recognized as the oldest male in the world following the deaths in 2019 of German Gustav Gerneth (in October), aged 114 years, and Japan's Masazo Nonaka (in January), at the age of 113, three months older than the German.

It remains to be seen who will be recognized after the death of Watanabe, the only male on the list drawn up by the Gerontology Research Group of the 30 oldest people in the world.

Japan has among the highest life expectancy in the world and the number of centenarians in the country has crossed 71,000, according to the latest government figures.

Since 2000, the number of centenarians censored has quintupled, raising concern for the economic outlook and future workforce of the country - where the birthrate is on a downward trend.

Out of these, 88 per cent are women.

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