36 killed as explosions rock Istanbul airport

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.

Istanbul, Jul 11: Turkish President Recep Tayyip Erdogan announced Friday that the Hagia Sophia, one of the architectural wonders of the world, would be reopened for Muslim worship, sparking fury in the Christian community and neighbouring Greece.

His declaration came after a top Turkish court revoked the sixth-century Byzantine monument's status as a museum, clearing the way for it to be turned back into a mosque.

The UNESCO World Heritage site in historic Istanbul, a magnet for tourists worldwide, was first constructed as a cathedral in the Christian Byzantine Empire but was converted into a mosque after the Ottoman conquest of Constantinople in 1453.

The Council of State, Turkey's highest administrative court, unanimously cancelled a 1934 cabinet decision to turn it into a museum and said Hagia Sophia was registered as a mosque in its property deeds.

The landmark ruling could inflame tensions not just with the West and Turkey's historic foe Greece but also Russia, with which Erdogan has forged an increasingly close partnership in recent years.

'Millions of Christians not heard'

Greece swiftly branded the move by Muslim-majority Turkey an "open provocation to the civilised world".

"The nationalism displayed by Erdogan... takes his country back six centuries," Culture Minister Lina Mendoni said in a statement.

The Russian Orthodox Church was equally scathing.

"The concern of millions of Christians were not heard," Church spokesman Vladimir Legoida told Interfax news agency.

The decision "shows that all pleas regarding the need to handle the situation extremely delicately were ignored," he said.

UNESCO chief Audrey Azoulay said she "deeply regrets" the decision made without prior dialogue with the UN's cultural agency.

The move was also condemned by the US Commission on International Religious Freedom, which said it was an "unequivocal politicisation" of the monument.

Hagia Sophia, which stands opposite the impressive Sultanahmet Mosque -- often called the Blue Mosque, has been a museum since 1935 and open to believers of all faiths.

Transforming it from a mosque was a key reform under the new republic born out of the ashes of the Ottoman Empire.

Sharing a presidential decree which named Hagia Sophia as a "mosque", Erdogan announced its administration would be handed over to Turkey's religious affairs directorate known as Diyanet.

"May we be blessed," he commented. The decree was published on the official gazette.

Erdogan has in recent years placed great emphasis on the battles which resulted in the defeat of Byzantium by the Ottomans, with lavish celebrations held every year to mark the conquest.

Muslim clerics have occasionally recited prayers in the museum on key anniversaries or religious holidays.

"The decision is intended to score points with Erdogan's pious and nationalist constituents," said Anthony Skinner of the risk assessment firm Verisk Maplecroft.

"Hagia Sophia is arguably the most conspicuous symbol of Turkey's Ottoman past -- one which Erdogan is leveraging to strengthen his base while snubbing domestic and foreign rivals," he told AFP.

'Chains broken'

A few hundred Turks carrying Turkish flags gathered outside Hagia Sophia shouting "Chains broken, Hagia Sophia reopened".

Police heightened security measures around the building, according to AFP journalists.

"It's been a dream since we were kids," said Erdal Gencler, an Istanbul resident.

"(Hagia Sophia) finds its true purpose again. We are very excited, proud, and hopeful that there will be beautiful services here," he added.

Fatma, a woman with tearful eyes, said: "Of course I am crying. (Hagia Sophia) belongs to us."

Ahead of the court decision, Justice Minister Abdulhamit Gul shared a picture of Hagia Sophia on his official Twitter account, with a message: "Have a good Friday."

Finance Minister Berat Albayrak, Erdogan's son-in-law, tweeted that Hagia Sophia would be reopened to Muslim worship "sooner or later", referring to a quote from Turkish poet Necip Fazil Kisakurek.

The Council of State had on July 2 debated the case brought by a Turkish group -- the Association for the Protection of Historic Monuments and the Environment, which demanded Hagia Sophia be reopened for Muslim prayers.

Since 2005, there have been several attempts to change the building's status. In 2018, the Constitutional Court rejected one application.

Despite occasional protests outside the site by Islamic groups, Turkish authorities had until now kept the building as a museum.

May 19: A Chinese laboratory has been developing a drug it believes has the power to bring the coronavirus pandemic to a halt.

The outbreak first emerged in China late last year before spreading across the world, prompting an international race to find treatments and vaccines.

A drug being tested by scientists at China's prestigious Peking University could not only shorten the recovery time for those infected, but even offer short-term immunity from the virus, researchers say.

Sunney Xie, director of the university's Beijing Advanced Innovation Center for Genomics, told AFP that the drug has been successful at the animal testing stage.

"When we injected neutralising antibodies into infected mice, after five days the viral load was reduced by a factor of 2,500," said Xie.

"That means this potential drug has (a) therapeutic effect."

The drug uses neutralising antibodies -- produced by the human immune system to prevent the virus infecting cells -- which Xie's team isolated from the blood of 60 recovered patients.

A study on the team's research, published Sunday in the scientific journal Cell, suggests that using the antibodies provides a potential "cure" for the disease and shortens recovery time.

Xie said his team had been working "day and night" searching for the antibody.

"Our expertise is single-cell genomics rather than immunology or virology. When we realised that the single-cell genomic approach can effectively find the neutralising antibody we were thrilled."

He added that the drug should be ready for use later this year and in time for any potential winter outbreak of the virus, which has infected 4.8 million people around the world and killed more than 315,000.

"Planning for the clinical trial is underway," said Xie, adding it will be carried out in Australia and other countries since cases have dwindled in China, offering fewer human guinea pigs for testing.

"The hope is these neutralised antibodies can become a specialised drug that would stop the pandemic," he said.

China already has five potential coronavirus vaccines at the human trial stage, a health official said last week.

But the World Health Organization has warned that developing a vaccine could take 12 to 18 months.

Scientists have also pointed to the potential benefits of plasma -- a blood fluid -- from recovered individuals who have developed antibodies to the virus enabling the body's defences to attack it.

More than 700 patients have received plasma therapy in China, a process which authorities said showed "very good therapeutic effects".

"However, it (plasma) is limited in supply," Xie said, noting that the 14 neutralising antibodies used in their drug could be put into mass production quickly.

Using antibodies in drug treatments is not a new approach, and it has been successful in treating several other viruses such as HIV, Ebola and Middle East Respiratory Syndrome (MERS).

Xie said his researchers had "an early start" since the outbreak started in China before spreading to other countries.

Ebola drug Remdesivir was considered a hopeful early treatment for COVID-19 -- clinical trials in the US showed it shortened the recovery time in some patients by a third -- but the difference in mortality rate was not significant.

The new drug could even offer short-term protection against the virus.

The study showed that if the neutralising antibody was injected before the mice were infected with the virus, the mice stayed free of infection and no virus was detected.

This may offer temporary protection for medical workers for a few weeks, which Xie said they are hoping to "extend to a few months".

More than 100 vaccines for COVID-19 are in the works globally, but as the process of vaccine development is more demanding, Xie is hoping that the new drug could be a faster and more efficient way to stop the global march of the coronavirus.

"We would be able to stop the pandemic with an effective drug, even without a vaccine," he said.