Love-struck Diana was willing to move to Pakistan: Jemima Khan

Washington, Jan 9: The U.S. and Iran stepped back from the brink of possible war Wednesday as President Donald Trump signaled he would not retaliate militarily for Iran's missile strikes on Iraqi bases housing U.S. troops. No one was harmed in the strikes, but U.S. forces in the region remained on high alert.

Speaking from the White House, Trump seemed intent on deescalating the crisis, which spiralled after he authorized the assassination of Iran's top general, Qassem Soleimani. Iran responded overnight by firing more than a dozen missiles at two installations in Iraq, its most direct assault on America since the 1979 seizure of the U.S. Embassy in Tehran.

Trump's takeaway was that “Iran appears to be standing down, which is a good thing for all parties concerned and a very good thing for the world.”

The region remained on edge, however, and American troops including a quick-reaction force dispatched over the weekend were on high alert. Hours after Trump spoke, an ‘incoming’ siren went off in Baghdad's Green Zone after what seemed to be small rockets “impacted” the diplomatic area, a Western official said. There were no reports of casualties.

Iran's Supreme Leader Ayatollah Ali Khamenei said the overnight strike was not necessarily the totality of Iran's response. “Last night they received a slap,” Khamenei said. “These military actions are not sufficient (for revenge). What is important is that the corrupt presence of America in this region comes to an end.”

The strikes had pushed Tehran and Washington perilously close to all-out conflict and left the world waiting to see whether the American president would respond with more military force. Trump, in his nine-minute, televised address, spoke of a robust U.S. military with missiles that are “big, powerful, accurate, lethal and fast.'' But then he added: “We do not want to use it."

Iran for days had been promising to respond forcefully to Soleimani's killing, but its limited strike on two bases--one in the northern Iraqi city of Irbil and the other at Ain al-Asad in western Iraq--appeared to signal that it too was uninterested in a wider clash with the U.S. Foreign minister Mohammad Javad Zarif tweeted that the country had “concluded proportionate measures in self-defence.”

Trump said the U.S. was “ready to embrace peace with all who seek it.” That marked a sharp change in tone from his warning a day earlier that “if Iran does anything that they shouldn't be doing, they're going to be suffering the consequences, and very strongly.”

Trump opened his remarks at the White House by reiterating his promise that “Iran will never be allowed to have a nuclear weapon.” Iran had announced in the wake of Soleimani's killing that it would no longer comply with any of the limits on uranium enrichment in the 2015 nuclear deal crafted to keep it from building a nuclear device.

The president, who had earlier pulled the U.S. out of the deal, seized on the moment of calm to call for negotiations toward a new agreement that would do more to limit Iran's ballistic missile programmes and constrain regional proxy campaigns like those led by Soleimani.

Trump spoke of new sanctions on Iran, but it was not immediately clear what those would be.

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.

Melbourne, Apr 10: Scientists have identified six drug candidates from more than 10,000 compounds that may help treat COVID-19.

The research, published in the journal Nature, tested the efficacy of approved drugs, drug candidates in clinical trials and other compounds.

"Currently there are no targeted therapeutics or effective treatment options for COVID-19," said Professor Luke Guddat from the University of Queensland in Australia.

"In order to rapidly discover lead compounds for clinical use, we initiated a programme of high-throughput drug screening, both in laboratories and also using the latest computer software to predict how different drugs bind to the virus," Guddat said.

The project targeted the main COVID-19 virus enzyme, known as the main protease or Mpro, which plays a pivotal role in mediating viral replication, the researchers said.

This makes it an attractive drug target for this virus, and as people don't naturally have this enzyme, compounds that target it are likely to have low toxicity, they said.

"We add the drugs directly to the enzyme or to cell cultures growing the virus and assess how much of each compound is required to stop the enzyme from working or to kill the virus. If the amount is small, then we have a promising compound for further studies," said Guddat.

After assaying thousands of drugs, researchers found of the six that appear to be effective in inhibiting the enzyme, one is of particular interest.

"We're particularly looking at several leads that have been subjected to clinical trials including for the prevention and treatment of various disorders such as cardiovascular diseases, arthritis, stroke, atherosclerosis and cancer," Guddat said.

Researchers said compounds that are already along the pipeline to drug discovery are preferred, as they can be further tested as antivirals at an accelerated rate compared to new drug leads that would have to go through this process from scratch.

"With continued and up-scaled efforts we are optimistic that new candidates can enter the COVID-19 drug discovery pipeline in the near future," Guddat said.