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Scientists have designed a “catch and kill” air filter which they say can trap the novel coronavirus and neutralise it instantly, an invention that may reduce the spread of COVID-19 in closed spaces such as schools, hospitals and health care facilities, as well as public transit environments like airplanes.

According to the study, published in the journal Materials Today Physics, the device killed 99.8 per cent of the novel coronavirus, SARS-CoV-2, in a single pass through its filter. It said the device, made from commercially available nickel foam heated to 200 degrees Celsius, also killed 99.9 per cent of the spores of the deadly bacterium Bacillus anthracis which causes the anthrax disease.

“This filter could be useful in airports and in airplanes, in office buildings, schools, and cruise ships to stop the spread of COVID-19,” said Zhifeng Ren, a co-author of the study from the University of Houston (UH) in the US.

“Its ability to help control the spread of the virus could be very useful for society,” Ren added.

The researchers said they are also developing a desk-top model for the device which is capable of purifying the air in an office worker’s immediate surroundings. According to the scientists, since the virus can remain in the air for about three hours, a filter that could remove it quickly was a viable plan, and with businesses reopening across the world, they believe controlling the spread in air conditioned spaces was urgent.

The study noted that the novel coronavirus cannot survive temperatures above 70 degrees Celsius, so by making the filter temperature far hotter — about 200 degree Celsius, the researchers said they were able to kill the virus almost instantly.

Ren said the nickel foam met several key requirements. “It is porous, allowing the flow of air, and electrically conductive, which allowed it to be heated. It is also flexible,” the researchers noted in a statement.But they added that nickel foam also had low resistivity, making it difficult to raise the temperature high enough to quickly kill the virus.

The researchers said they solved this problem by folding the foam, connecting multiple compartments with electrical wires to increase the resistance high enough to raise the temperature as high as 250 degrees Celsius. By making the filter electrically heated, rather than heating it from an external source, they said the the amount of heat that escaped from the filter is minimised, allowing air conditioning to function with very low strain.

When the scientists built and tested a prototype for the relationship between voltage/current and temperature, they said it satisfies the requirements for conventional heating, ventilation, and air conditioning (HVAC) systems, and could kill the coronavirus.

“This novel biodefense indoor air protection technology offers the first-in-line prevention against environmentally mediated transmission of airborne SARS-CoV-2, and will be on the forefront of technologies available to combat the current pandemic and any future airborne biothreats in indoor environments,” said Faisal Cheema, another co-author of the study from UH.

The researchers have called for a phased roll-out of the device, “beginning with high-priority venues, where essential workers are at elevated risk of exposure.” They believe the novel device will both improve safety for frontline workers in essential industries and allow nonessential workers to return to public work spaces.

17-year-old Pratyusha Jha, wakes up scrambling for newspapers these days to look for any news about her pending board exams and is anxious about what the future has in store for her.

Similar concerns are shared by Bipin Kumar, a class 12 student, who says the announcement of board exams from July 1 to 15 brought limited clarity as the larger questions remain unanswered.

The COVID-19 lockdown, came with a different set of concerns for class 12 students, whose board exams were postponed midway following the outbreak of coronavirus, putting on hold their future plans as well.

"Everyday I have been looking for news about the exams and about entrance exam dates. I feel unfortunate that this happened during the year I was supposed to take the big college leap. I don't want my future decisions to be shaped by this very year as what I opt to study now will remain with me lifelong," Pratyusha told PTI.

Ending some uncertainty for students, HRD Minister Ramesh Pokhriyal 'Nishank' on Friday announced that the pending class 10 and 12 board exams will be held from July 1 to 15. While class 12 exams will be conducted across the country, the class 10 exams are only pending in North East Delhi where they were affected due to the law and order situation.

"The anxiety doesn't end here, there is no date sheet yet. What will be the modalities of exams, how will we reach centres, what protocols have to be followed, there is no clarity on that. My friends and I keep calling our school teachers and also the CBSE helpline to seek some clarity," Bipin Kumar said.

Vaibhav Sharma, a class 12 student in Gurgaon said, "There is no clarity yet. I wanted to apply for DU, but now that the exams are taking place in July when will the results be declared, when will cut offs be announced. If I don't get a good college here, will I be able to travel to different cities for admission, nothing is known yet."

Similarly, for the students in northeast Delhi, the wait for the exams has become a "test of patience" as they were postponed first in the area due to law and order situation, and later due to the coronavirus outbreak, resulting in a four-month-long wait for the exams.

"It has become an endless wait and now I don't feel like studying too. Right from childhood, we are taught that board exams are too crucial and have to be focussed at least two years in advance. But now, it is a different picture altogether," Rani Kumari, a resident of Chandbagh said.

Universities and schools across the country have been closed and exams postponed since March 16 when the Centre announced a countrywide classroom shutdown as one of the measures to contain the COVID-19 outbreak.

Later, a nationwide lockdown was announced on March 24, which has now been extended till May 17.

The board was not able to conduct class 10 and 12 exams on eight examination days due to the coronavirus outbreak. Further, due to the law and order situation in North East Delhi, the board was not able to conduct exams on four examination days, while a very small number of students from and around this district were not able to appear in exams on six days.

The board had last month announced that it will only conduct pending exams in 29 subjects which are crucial for promotion and admission to higher educational institutions. The modalities of assessment for the subjects for which exams are not being conducted will be announced soon by the board.

The schedule has been decided in order to ensure that the board exams are completed before competitive examinations such as engineering entrance JEE-Mains, which is scheduled from July 18-23, and medical entrance exam NEET, which is scheduled on July 26.

The University Grants Commission (UGC) has issued guidelines to universities that new academic session for freshers will begin from September while for the existing students from August.

COVID-19 mostly kills through an overreaction of the immune system, whose function is precisely to fight infections, say scientists who have decoded the mechanisms, symptoms, and diagnosis of the disease caused by the SARS-Cov-2 coronavirus.

In a study published in the journal Frontiers in Public Health, the researchers explained step-by-step how the virus infects the airways, multiplies inside cells, and in severe cases causes the immune defences to overshoot with a "cytokine storm".

This storm is an over-activation of white blood cells, which release too-great amounts of cytokines -- inflammation-stimulating molecules --into the blood, they said.

"Similar to what happens after infection with SARS and MERS, data show that patients with severe COVID-19 may have a cytokine storm syndrome," said study author Daishun Liu, Professor at Zunyi Medical University in China.

"The rapidly increased cytokines attract an excess of immune cells such as lymphocytes and neutrophils, resulting in an infiltration of these cells into lung tissue and thus cause lung injury," Liu said.

The researchers explained that the cytokine storm ultimately causes high fever, excessive leakiness of blood vessels, and blood clotting inside the body.

It also causes extremely low blood pressure, lack of oxygen and excess acidity of the blood, and build-up of fluids in the lungs, they said.

The researchers noted that white blood cells are misdirected to attack and inflame even healthy tissue, leading to failure of the lungs, heart, liver, intestines, kidneys, and genitals.

This multiple organ dysfunction syndrome (MODS) may worsen and shutdown the lungs, a condition called acute respiratory distress syndrome, (ARDS), they said.

This, the researchers explained, happens due to the formation of a so-called hyaline membrane -- composed of debris of proteins and dead cells -- lining the lungs, which makes absorption of oxygen difficult.

Most deaths due to COVID-19 are therefore due to respiratory failure, they said.

The researchers explained that in the absence of a specific antiviral cure for COVID-19, the goal of treatment must be to the fight the symptoms, and lowering the mortality rate through intensive maintenance of organ function.

For example, an artificial liver blood purification system or renal replacement therapy can be used to filter the blood through mechanical means, they said.

The team noted that especially important are methods to supplement or replace lung function, for example with non-invasive mechanical ventilation through a mask, ventilation through a tube into the windpipe, the administration of heated and humidified oxygen via a tube in the nose, or a heart-lung bypass.

The researchers stressed the importance of preventing secondary infections.

They noted that SARS-Cov-2 also invades the intestines, where it causes inflammation and leakiness of the gut lining, allowing the opportunistic entry of other disease-causing microorganisms.

The researchers advocate that this should be prevented with nutritional support, for example with probiotics -- beneficial bacteria that protect against the establishment of harmful ones -- and nutrients and amino acids to improve the immune defences and function of the intestine.

"Because treatment for now relies on aggressive treatment of symptoms, preventative protection against secondary infections, such as bacteria and fungi, is particularly important to support organ function, especially in the heart, kidneys, and liver, to try and avoid further deterioration of their condition," Liu added.