Amma: A tenacious leader who broke the glass ceiling

Washington DC, Jun 8: Astronomers acting on a hunch have likely resolved a mystery about young, still-forming stars and regions rich in organic molecules closely surrounding some of them.

They used the National Science Foundation's Karl G Jansky Very Large Array (VLA) to reveal one such region that previously had eluded detection and that revelation answered a longstanding question.

The regions around the young protostars contain complex organic molecules which can further combine into prebiotic molecules that are the first steps on the road to life.

The regions, dubbed "hot corinos" by astronomers, are typically about the size of our solar system and are much warmer than their surroundings, though still quite cold by terrestrial standards.

The first hot corino was discovered in 2003 and only about a dozen have been found so far. Most of these are in binary systems, with two protostars forming simultaneously.

Astronomers have been puzzled by the fact that, in some of these binary systems, they found evidence for a hot corino around one of the protostars but not the other.

"Since the two stars are forming from the same molecular cloud and at the same time, it seemed strange that one would be surrounded by a dense region of complex organic molecules and the other wouldn't," said Cecilia Ceccarelli, of the Institute for Planetary Sciences and Astrophysics at the University of Grenoble (IPAG) in France.

The complex organic molecules were found by detecting specific radio frequencies, called spectral lines, emitted by the molecules. Those characteristic radio frequencies serve as "fingerprints" to identify the chemicals.

The astronomers noted that all the chemicals found in hot corinos had been found by detecting these "fingerprints" at radio frequencies corresponding to wavelengths of only a few millimetres.

"We know that dust blocks those wavelengths, so we decided to look for evidence of these chemicals at longer wavelengths that can easily pass through dust," said Claire Chandler of the National Radio Astronomy Observatory, and principal investigator on the project.

"It struck us that dust might be what was preventing us from detecting the molecules in one of the twin protostars," added Chandler.

The astronomers used the VLA to observe a pair of protostars called IRAS 4A, in a star-forming region about 1,000 light-years from Earth. They observed the pair at wavelengths of centimetres.

At those wavelengths, they sought radio emissions from methanol, CH3OH (wood alcohol, not for drinking). This was a pair in which one protostar clearly had a hot corino and the other did not, as seen using the much shorter wavelengths.

The result confirmed their hunch. "With the VLA, both protostars showed strong evidence of methanol surrounding them. This means that both protostars have hot corinos. The reason we did not see the one at shorter wavelengths was because of dust," said Marta de Simone, a graduate student at IPAG who led the data analysis for this object.

The astronomers cautioned that while both hot corinos now are known to contain methanol, there still may be some chemical differences between them. That, they said, can be settled by looking for other molecules at wavelengths not obscured by dust.

"This result tells us that using centimetre radio wavelengths is necessary to properly study hot corinos," Claudio Codella of Arcetri Astrophysical Observatory in Florence, Italy, said.

"In the future, planned new telescopes such as the next-generation VLA and SKA, will be very important to understanding these objects," added Codella.

The Mars Colour Camera (MCC) onboard ISRO's Mars Orbiter Mission has captured the image of Phobos, the closest and biggest moon of Mars.

The image was taken on July 1 when MOM was about 7,200 km from Mars and 4,200 km from Phobos.

"Spatial resolution of the image is 210 m.

This is a composite image generated from 6 MCC frames and has been color corrected," ISRO said in an update along with the image.

Phobos is largely believed to be made up of carbonaceous chondrites.

According to ISRO, "the violent phase that Phobos has encountered is seen in the large section gouged out from a past collision (Stickney crater) and bouncing ejecta."

"Stickney, the largest crater on Phobos along with the other craters (Shklovsky, Roche & Grildrig) are also seen in this image," it said.

The mission also known as Mangalyaan was initially meant to last six months, but subsequently ISRO had said it had enough fuel for it to last "many years."

The country had on September 24, 2014 successfully placed the Mars Orbiter Mission spacecraft in orbit around the red planet, in its very first attempt, thus breaking into an elite club.

ISRO had launched the spacecraft on its nine-month- long odyssey on a homegrown PSLV rocket from Sriharikota in Andhra Pradesh on November 5, 2013.

It had escaped the earth's gravitational field on December 1, 2013.

The Rs 450-crore MOM mission aims at studying the Martian surface and mineral composition as well as scan its atmosphere for methane (an indicator of life on Mars).

The Mars Orbiter has five scientific instruments - Lyman Alpha Photometer (LAP), Methane Sensor for Mars (MSM), Mars Exospheric Neutral Composition Analyser (MENCA), Mars Colour Camera (MCC) and Thermal Infrared Imaging Spectrometer

May 30: Patients undergoing surgery after contracting the novel coronavirus are at an increased risk of postoperative death, according to a new study published in The Lancet journal which may lead to better treatment guidelines for COVID-19.

In the study, the scientists, including those from the University of Birmingham in the UK, examined data from 1,128 patients from 235 hospitals from a total of 24 countries.

Among COVID-19 patients who underwent surgery, they said the death rates approach those of the sickest patients admitted to intensive care after contracting the virus.

The scientists noted that SARS-CoV-2 infected patients who undergo surgery, experience substantially worse postoperative outcomes than would be expected for similar patients who do not have the infection.

According to the study, the 30-day mortality among these patients was nearly 24 per cent.

The researchers noted that mortality was disproportionately high across all subgroups, including those who underwent elective surgery (18.9 per cent), and emergency surgery (25.6 per cent).

Those who underwent minor surgery, such as appendicectomy or hernia repair (16.3 per cent), and major surgery such as hip surgery or for colon cancer also had higher mortality rates (26.9 per cent), the study said.

According to the study, the mortality rates were higher in men versus women, and in patients aged 70 years or over versus those aged under 70 years.

The scientists said in addition to age and sex, risk factors for postoperative death also included having severe pre-existing medical problems, undergoing cancer surgery, undergoing major procedures, and undergoing emergency surgery.

"We would normally expect mortality for patients having minor or elective surgery to be under 1 per cent, but our study suggests that in SARS-CoV-2 patients these mortality rates are much higher in both minor surgery (16.3%) and elective surgery (18.9%)," said study co-author Aneel Bhangu from the University of Birmingham.

Bhangu said these mortality rates are greater than those reported for even the highest-risk patients before the pandemic.

Citing an example from the 2019 UK National Emergency Laparotomy Audit report, he said the 30-day mortality was 16.9 per cent in the highest-risk patients.

Based on an earlier study across 58 countries, Bhangu said the 30-day mortality was 14.9 per cent in patients undergoing high-risk emergency surgery.

"We recommend that thresholds for surgery during the SARS-CoV-2 pandemic should be raised compared to normal practice," he said.

"For example, men aged 70 years and over undergoing emergency surgery are at particularly high risk of mortality, so these patients may benefit from their procedures being postponed," Bhangu added.

The study also noted that patients undergoing surgery are a vulnerable group at risk of SARS-CoV-2 exposure in hospital.

It noted that the patients may also be particularly susceptible to subsequent pulmonary complications, due to inflammatory and immunosuppressive responses to surgery and mechanical ventilation.

The scientists found that overall in the 30 days following surgery 51 per cent of patients developed a pneumonia, acute respiratory distress syndrome, or required unexpected ventilation.

Nearly 82 per cent of the patients who died had experienced pulmonary complications, the researchers said.

"Worldwide an estimated 28.4 million elective operations were cancelled due to disruption caused by COVID-19," said co-author Dmitri Nepogodiev from the University of Birmingham.

"Our data suggests that it was the right decision to postpone operations at a time when patients were at risk of being infected with SARS-CoV-2 in hospital," Nepogodiev said.

According to the researchers, there's now an urgent need for investment by governments and health providers in to measures which ensure that as surgery restarts patient safety is prioritised.

They said this includes the provision of adequate personal protective equipment (PPE), establishment of pathways for rapid preoperative SARS-CoV-2 testing, and consideration of the role of dedicated 'cold' surgical centres.