The Omicron Covid variant has been found to multiply about 70 times quicker than the original and Delta versions of coronavirus in tissue samples taken from the bronchus (支气管), the main tubes from the windpipe to the lungs, in laboratory experiments that could help explain its rapid transmission.

The study, by a team from the University of Hong Kong, also found that the new variant grew 10 times slower in lung tissue, which the authors said could be an indicator of lower disease severity.

Michael Chan, who led the work, said the result needed to be interpreted with caution because severe disease is determined not only by how quickly the virus replicates (复制) but also by a person's immune response. "It is also noted that by infecting many more people, a very infectious virus may cause more severe disease and death even though the virus itself may be less pathogenic (致病的), " he said. "Therefore, taken together with our recent studies showing that the Omicron variant can partially escape immunity from vaccines and past infection, the overall threat from the Omicron variant is likely to be very

significant. "

Jeremy Kamil, an associate professor of microbiology and immunology at Louisiana State University Health Shreveport, pointed out that Delta, which turned out to be more pathogenic, showed a similar pattern of replicating more slowly in the lungs. "These authors found Omicron replicates fantastically well--even far better than either Delta or the original virus--in bronchial tissue, " Kamil said. "This could in some ways contribute to an advantage in transmission between people. "

Kamil added, "Of course, a huge component of Omicron's transmissibility in real life is going to be its potential to escape neutralising antibodies that protect against infection in the first place. It's very likely spreading well even between vaccinated people, especially those who haven't recently gotten a booster shot. "

The findings, together with other recent work showing Omicron infects cells more readily, add to an emerging picture that the variant may be intrinsically more transmissible in addition to escaping existing immunity.

Hundreds of people die at sea every year due to ship and airplane accidents. Emergency teams have little time to rescue those in the water because the probability of finding a person alive fall dramatically after six hours. Beyond tides and challenging weather conditions, unsteady coastal currents often make search and rescue operations extremely difficult.

New insight into coastal flows gained by an international research team led by George Haller, Professor of Nonlinear Dynamics at ETH Zurich, promises to enhance the search and rescue techniques currently in use. Using tools from dynamical systems theory and ocean data, the team has developed an algorithm (算法) to predict where objects and people floating in water will go. "Our work has a clear potential to save lives," says Mattia Serra, the first author of a study recently published in Nature Communications.

In today's rescue operations at sea, complicated models of ocean dynamics and weather forecasting are used to predict the path of floating objects. For fast-changing coastal waters, however, such predictions are often inaccurate due to uncertain boundaries and missing data. As a result, a search may be launched in the wrong location, causing a loss of precious time.

Haller's research team obtained mathematical results predicting that objects floating on the ocean's surface should gather along a few special curves (曲线) which they call TRansient Attracting Profiles (TRAPs). These curves can't be seen with our eyes but can be tracked from instant ocean surface current data using recent mathematical methods developed by the ETH team. This enables quick and precise planning of search paths that are less sensitive to uncertainties in the time and place of the accident.

In cooperation with a team from MIT, the ETH team tested their new, TRAP-based search algorithm in two separate ocean experiments near Martha's Vineyard, which is on the northeastern coast of the United States. Working from the same real-time data available to the Coast Guard, the team successfully identified TRAPs in the region in real time. They found that buoys and manikins (浮标和人体模型) thrown in the water indeed quickly gathered along these emerging curves. "Of several competing approaches tested in this project, this was the only algorithm that consistently found the right location," says Haller.

"Our results are rapidly obtained, easy to interpret and cheap to perform," points out Serra. Haller stresses: "Our hope is that this method will become a standard part of the tool kit of coast guards everywhere. "

The body gives off many gases. Although some smells may signal a need to bathe or that you ate a certain meal, other gases might point to serious disease. Now, researchers have come up with a system that uses earmuffs to catch the disease-signaling gases. Doctors could get the information as patients wear a set of earmuffs. Results could be ready within minutes. 

"The ear is a good place to monitor," explains Johnson, a biomedical engineer. The ear's skin is fairly thin, he notes. So gases don't have to travel far to get out of the blood and escape through skin pores（毛孔）.

To collect the gases,  Johnson and his team selected earmuffs that make a tight seal（密封）with the head. These are the type people often wear to protect the ears from loud noise. His team made two holes in the muff covering one ear. A tube slowly pumped air in one hole. Another tube pulled air out of the second hole and sent it to a sensor. 

In their tests, the team found that they could measure changes in the amount of alcohol coming from the skin of the ear. It could work much like a Breathalyzer that police use to test people for driving drunk. The team invited three men. Each had to avoid drinking alcohol for at least three days before taking part. Once in the lab, these men wore the earmuffs and sat for 10 minutes as the system recorded normal gas levels leaving their ears. Afterward, the men drank a big amount of alcohol. About 7 minutes later, the earmuff system tested out a rise in alcohol leaving the skin. After 50 minutes, alcohol levels reached the peak and continued falling until the test was over. 

The team then measured other gases by changing out the sensor. With the right sensor, their earmuff system could test out disease. Later, they replaced the earmuffs with a one-eared version to make it a bit more comfortable. 

Johnson imagines another possible benefit. The earmuff system could help doctors tell whether a child's ear infections （感染） have been caused by bacteria or a virus. How? Each type of infection exudes different gases. That, in turn, could guide how doctors cure the disease.