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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.

Europe, Jan 11: Researchers have revealed the people who drink tea at least three times a week have healthy years of life and longer life expectancy.

The research was published in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).

Dr Xinyan Wang, who is the author of the study, said: "Habitual tea consumption is associated with lower risks of cardiovascular disease and all-cause death. The favourable health effects are the most robust for green tea and for long-term habitual tea drinkers."
The analysis that was conducted included about 100,902 participants of the China-PAR project2 with no history of heart attack, stroke, or cancer.

Participants were classified into two groups: Habitual tea drinkers and never or non-habitual tea drinkers and followed-up for a median of 7.3 years.

The analyses estimated that 50-year-old habitual tea drinkers would develop coronary heart disease and stroke 1.41 years later and live 1.26 years longer than those who never or seldom drank tea. Compared with never or non-habitual tea drinkers, the habitual tea consumers had a 20 per cent lower risk of incident heart disease and stroke, 22 per cent lower risk of fatal heart disease and stroke, and 15 per cent decreased risk of all-cause death.

The potential influence of changes in tea drinking behaviour was suspected in a subset of 14,081 participants with assessments at two-time points. The average duration between the two surveys was 8.2 years, and the median follow-up after the second survey was 5.3 years.

Habitual tea drinkers who maintained their habit in both surveys had a 39 per cent lower risk of incident heart disease and stroke, 56 per cent lower risk of fatal heart disease and stroke, and 29 per cent decreased risk of all-cause death compared to consistent never or non-habitual tea drinkers.

Senior author Dr Dongfeng Gu said: "The protective effects of tea were most pronounced among the consistent habitual tea drinking group. Mechanism studies have suggested that the main bioactive compounds in tea, namely polyphenols, are not stored in the body long-term. Thus, frequent tea intake over an extended period may be necessary for the cardioprotective effect."

In a subanalysis by type of tea, drinking green tea was linked with approximately 25 per cent lower risks for incident heart disease and stroke, fatal heart disease and stroke, and all-cause death. However, no significant associations were observed for black tea.
Dr Gu noted that a preference for green tea is unique to East Asia.

Two factors may be at play. First, green tea is a rich source of polyphenols which protect against cardiovascular disease and its risk factors including high blood pressure and dyslipidaemia. Black tea is fully fermented and during this process, polyphenols are oxidised into pigments and may lose their antioxidant effects. Second, black tea is often served with milk, which previous research has shown may counteract the favourable health effects of tea on vascular function.

Gender-specific analyses showed that the protective effects of habitual tea consumption were pronounced and robust across different outcomes for men, but only modest for women. Dr Wang said: "One reason might be that 48 per cent of men were habitual tea consumers compared to just 20 per cent of women. Secondly, women had a much lower incidence of, and mortality from, heart disease and stroke. These differences made it more likely to find statistically significant results among men."

She said: "The China-PAR project is ongoing, and with more person-years of follow-up among women the associations may become more pronounced."

In conclusion, the authors have found that randomised trials are required to validate the results and to illustrate nutritional guidelines and advice for lifestyle.