The virus that causes COVID-19 spreads through the air. But just how much virus people breathe out over the course of infection isn’t well-defined.
To pin the numbers down, olfactory researcher Gregory Lane and colleagues analyzed over 300 breath samples from 43 people with COVID-19, following them for nearly three weeks. Levels varied between and within individuals, but some people shed a lot, releasing over 800 copies of viral RNA per minute at times.
On average, participants breathed out 80 copies per minute for a full eight days after symptoms began, the team reports September 8 in a preprint posted at medRxiv.org. Only after that point did the viral particles drop to nearly undetectable levels. Lane, of Northwestern University Feinberg School of Medicine in Chicago, and colleagues still need to confirm what percentage of that exhaled viral RNA comes from viruses that can still replicate in another person’s body. And scientists don’t yet know how much virus is required for infection.
But, based on the new data, the team estimates that a high shedder could potentially exhale enough virus to infect someone in a closed space in about 20 seconds, making even elevator rides risky. With an average shedder, infection could take a little under four minutes.
The new study, which will be published in eLife, provides valuable information that both nasal swab studies and one-time aerosol experiments cannot, says infectious diseases researcher Kristen Coleman (SN: 7/16/23). Swabs sample only one part of the respiratory tract. And many aerosol experiments measure the amount of virus people spewed while talking, singing or reading aloud, as well as while while breathing, at just a single point during infection (SN: 08/17/21).
Lane’s team devised a simple and cheap tool — essentially a plastic mouthpiece attached to a closed tube — that participants took home with them and breathed into for 10 minutes at a time. That allowed the team to easily collect samples over an extended period of time and track how emissions changed during infection. But the makeshift tool lacks the precision of advanced machines in laboratories and hospitals, says Coleman, of the University of Maryland School of Public Health in College Park. Even the spike of 876 viral RNA copies per minute seen in the new study may be an underestimate by several orders of magnitude, she says.
In the new study, those who reported more severe symptoms tended to emit more virus. Yet even asymptomatic people or those with mild cases breathed out substantial amounts of viral RNA. Both vaccinated and unvaccinated people exhaled similar levels.
The U.S. Centers for Disease Control and Prevention currently recommends that people who are mildly ill or asymptomatic isolate for at least five days and then mask for another five. Lane would offer different advice: “If my friends or family asked me, I’d say you should isolate through day eight.”
Members of a post-disaster reconstruction working group recently walked into the flooded Xinle village, located in Wuchang city of Northeast China's Heilongjiang Province, to investigate and identify flood-hit houses. According to estimates, review of all the homes in 24 townships will complete in three to four days.
In the aftermath of Typhoon Doksuri, Heilongjiang and multiple other regions in China, including Beijing and North China's Hebei Province, have ramped up efforts to restore order for people living in inundated areas.
In Guyu village, Wuchang city, more than 2,000 mu (133 hectares) of corn has been soaked in water. The local emergency department has transferred large-scale pumping facilities to carry out 24-hour drainage of farmland water. Wuchang has mobilized six post-disaster technical guidance groups to provide technical guidance for villagers in 24 towns and villages for draining field water and spraying pesticides to prevent and control pests and diseases.
At Sunday midnight, a train carrying 690 tons of Wuchang rice left the local train station. This was the first train of food supplies transported from Wuchang station after the resumption of the railway, which was cut off by flooding.
People wearing protective gear for disinfection in Shangzhi, one of the seriously stricken cities in Heilongjiang, have completed three rounds of disinfection across more than 320,000 square meters of flood-affected areas.
In response to the flooding of farmland, Hebei Province organized experts and technicians to head to the front lines of the disaster resistance to guide post-disaster agricultural production. At the same time, the province promptly redirected 1.06 million kilograms of seeds of short-growth crops such as cabbage and spinach to prepare for replanting to minimize farmers' losses.
In Zhuozhou, Hebei, four shopping malls and 29 supermarket chains have resumed operation and schools are also stepping up efforts to clean up sludge and disinfect areas to ensure the timely return of students to campus in September. Hebei officials had said earlier that it plans to complete the reconstruction in two years and will take efforts to ensure affected residents are able to return to their homes prior to the approach of winter.
In Beijing, the lives of local people have gradually resumed. Most recently, six A-level scenic spots in the Fangshan district have reopened. The Fangshan district has labeled regions into three colors based on the severity of flood impact - red, yellow and green - serving as a more efficient method to solve disaster relief work. Officials from Beijing said they have mapped out a plan to improve the city's disaster relief capabilities and the development of flooded regions over the next three years.
Not only have local departments in flood-stricken regions moved quickly to deal with disaster relief, the Ministry of Agriculture and Rural Affairs urged agricultural departments at all levels to make efforts to alleviate disaster and promote vegetable production.
Meanwhile, to deal with future emergent heavy rainfall and floods and improve the adaptability of urban infrastructure to withstand extreme weather, observers have suggested that the impact infrastructure in some high-risk areas may face from extreme rainstorms brought by climate change be re-evaluated to determine whether the existing level of defense needs to be upgraded, as well as to improve the vigilance and preparedness of local departments and strengthen resilience in the face of a changing climate.
Some water control experts said this round of heavy rainfall reminded some places to make up for the shortcomings of local flood control projects. They pointed out some northern cities in recent years have relaxed their vigilance and constructed flood storage areas in a disorderly manner, such as when building houses, locals may take soil from earth dams, which weakens the flood control capacity of levees.
Sun Shao, a senior researcher at Chinese Academy of Meteorological Sciences, told the Global Times that challenges encountered by cities in northern China due to deficient drainage systems, limited river networks, and inadequate urban green space planning, makes them highly vulnerable to flooding during unexpected heavy rainfall.
Cheng Xiaotao, a deputy chief engineer from the China Institute of Water Resources and Hydropower Research (IWHR), told the Global Times that besides flood control projects, effective communication about the severity of extreme weather among meteorological, hydrological and water conservancy departments is crucial. For instance, emergency command departments can compile data about the specific precipitation and flow rate of rivers and inform the public in detail.
As heavy rainfall events intensify, there is a higher probability of sudden flash floods, mudslides, and other disasters, Sun said. He explained that reviewing historical patterns, during the 1950s to 1970s, the main rain belt was concentrated in northern China, which later shifted to southern China in the 1980s and 1990s. Since the beginning of the 21st century, the main rain belt has gradually moved northward again.
The Democratic Progressive Party (DPP) authorities' collusion with external forces will only push Taiwan into the abyss of disaster, said a Chinese mainland Taiwan affairs official at the opening of a major cross-Straits academic seminar in Chengdu, Southwest China's Sichuan Province on Thursday, alluding to the deputy leader of Taiwan island Lai Ching-te's provocative "transit" through the US.
Hosted by Cross-Straits Relations Research Center affiliated with the Taiwan Affairs Office of the State Council and with a theme of "cross-Straits relations and national rejuvenation," the two-day seminar has attracted more than 130 scholars and think tank experts from both sides of the Taiwan Straits. The 2023 seminar marks the biggest face-to-face gathering for scholars from both sides of the Taiwan Straits after the three-year COVID-19 pandemic. Responding to Lai's "stopover" in the US, Pan Xianzhang, vice director of both the Taiwan Work Office of the Communist Party of China Central Committee and the Taiwan Affairs Office of the State Council, said during the opening that the interests of Taiwan compatriots are damaged by each and every "stopover" in the US made by Taiwan secessionists.
The attempts by Taiwan secessionists to seek "independence" and create provocation in collusion with external forces in the name of making "stopovers" fully reveals that they are troublemakers undermining the peace and stability in the Taiwan Straits, Pan said.
Noting that at present, cross-Straits relations are faced with major choices - peace or war, prosperity or recession - Pan urged Taiwan compatriots to stand on the right side of history, uphold the 1992 Consensus, firmly oppose Taiwan secessionists and interference by external forces, and join hands with compatriots in the Chinese mainland to maintain peaceful development of cross-Straits relations and advance integrated development across the Straits.
Experts and scholars attending the seminar said that the DPP authorities' collusion with external forces to seek "Taiwan independence" and create provocation is "pushing Taiwan to the brink of war" and has seriously undermined the fundamental interests of the Chinese nation. With the 2024 Taiwan regional election looming, the two sides of Straits are standing at a crossroads.
Xie Yu, a Taiwan affairs expert at the China Institutes of Contemporary International Relations, said 2023 is the first year of the resumption of cross-Straits exchanges after the COVID-19 pandemic, and the demand for exchanges, cooperation and integration accumulated by people on both sides of Straits need to be released. However, collusion between Taiwan secessionists and external forces has strained cross-Straits ties.
"Taiwan island should not become a powder keg in Asia. It should not become an ATM for US arms dealers. It should not become a runway for Western politicians," Xie said. "The mainland's moves against secessionists and external interference are actually meant to safeguard the prospects for peace across the Taiwan Straits and the well-being of the people on both sides."
Li Peng, head of the Graduate Institute for Taiwan Studies of Xiamen University, said that the mainland has always emphasized that peaceful reunification is the first choice, and the mainland strives for the prospect of peaceful reunification with the greatest sincerity and efforts.
However, the strategic competition between the US and China has intensified, the collusion between secessionists and US has deepened, and cross-Straits exchanges have been hindered. If the DPP authorities and the US ignore the mainland's strategic patience and determination and continue to challenge its red line, the situation may go in a direction that no one is willing to go, Li said.
Liu Guoshen, head of the Collaborative Innovation Center for Peaceful Development of Cross-Straits Relation, told the Global Times on Thursday that the rapid development of the Chinese mainland has brought about a high degree of maladjustment in the US and Taiwan island, which then led to the appearance of "stress syndrome," and an "overly defensive mentality."
Over the past few years, every time the US played the Taiwan card, it gave the Chinese mainland an opportunity to leverage its power through countermeasures. The mainland is very clear where the line is, so if the US wants to play the Taiwan card constantly, the "Taiwan card" may be completely confiscated in the end, Liu said.
The Taiwan question needs to be resolved in line with the great rejuvenation of the Chinese nation, the ultimate resolution lies in the development and strength of the Chinese mainland, Liu noted.
There is absolutely no possibility of Taiwan's independence. For Taiwan island, its only way out is to find its own value and positioning during the process of the great rejuvenation of the Chinese nation, the expert said.
Taiwan independence is a dead end facing the choice between war and peace. The two sides need to deepen integration and development, which can achieve the maximum well-being of Taiwan compatriots and protect their political, economic and security interests, said Yang Yizhou, a vice chairman of the All-China Association of Taiwan Compatriots.
A Japanese restaurant in Shanghai has introduced and then removed an "anti-radiation" set meal after netizens questioned the dishes' radiation-proof function and criticized the restaurant for false advertising.
The Japanese government's dumping of nuclear-contaminated wastewater into the Pacific Ocean has hit Japanese restaurants in China with some temporarily closing or emphasized their ingredients not imported from Japan. Others considered transitioning their business focus or urgently changing their operating names.
Netizens found that one Japanese restaurant in Shanghai was promoting an "anti-radiation" double combo meal on Dianping, China's leading local lifestyle information and trading platform on Thursday, which consisted of tomatoes, green soybeans, spinach, chicken, and beef at the price of 180 yuan (roughly $25).
On the introduction page for the set meal, the anti-radiation effect of each dish was noted in detail. For example, "trace elements such as iron and magnesium promote metabolism for radiation protection" was noted behind the cold dish chilled tofu. The menu also noted that tomato salad has the function of "effectively reducing radiation-induced skin damage".
According to an employee from the restaurant, all main ingredients were home-grown after Japan started dumping nuclear-contaminated wastewater. Regarding the anti-radiation effects of the meal, the employee said that there was no specific scientific basis outside the head chef's careful selection of produce after gathering information and seeking advice from nutritionists.
But the set meal was quickly removed on Saturday after it became a trending topic on China's Twitter-like social media platform Sina Weibo with more than 90 million views and comments.
Some netizens said the set meal was a clear case of false advertising given its unfounded anti-radiation functions. Others criticized the restaurant for taking advantage of consumer anxiety over the Japanese wastewater dumping plan.
The "anti-radiation" meal, which exaggerated the functions of food and created misleading claims, is false commercial advertising prohibited by China's Anti-Unfair Competition Law, Fu Jian, the director of Henan Zejin Law Firm, told several media outlets.
Fu said that once proven to be false advertising, the responsible parties involved could face legal consequences, including compensating consumers for their losses and paying fines, among other penalties.
Starting from Thursday, China banned the import of aquatic products from Japan in order to prevent any nuclear-contaminated food from entering China. Many Japanese restaurants in China including Sushiro, Yoshinoya, Kinsho Sushi, DaiYuu Sushi said they will replace ingredients imported from Japan with those from other countries and regions.
According to the Shanghai Fisheries Industry Association, bluefin tuna and sea urchin are the most popular and highest-selling Japanese imported ingredients on Chinese dining tables, which are commonly featured in mid-to-high-end Japanese restaurants.
Fresh produce markets RT-Mart and Fresh Hema told media that the primary seafood products they offer are salmon and tuna. Currently, salmon is mainly imported from Norway and Chile, while imports of bluefin tuna from Japan has been suspended two months ago due to safety concerns.
China is considering holding degree holders who use artificial intelligence (AI) to ghostwrite their theses legally responsible. The draft of the Degree Law was submitted to the Standing Committee of the 14th National People's Congress, China's top legislature, for deliberation on Monday.
The draft lays out legal responsibilities for actions such as degree holders using or impersonating another's identity to gain admission qualifications, employing artificial intelligence to author thesis papers, and institutions granting degrees unlawfully, as reported by the media on Monday.
Academic misconduct includes plagiarism, forgery, data falsification, using artificial intelligence to produce a thesis, impersonating another's identity to obtain admission qualifications, and securing admission qualifications and graduation certificates through illicit means like favoritism and cheating. The draft also addresses other illegal or irregular behaviors that, when exhibited during the study period, should prevent the awarding of a degree.
The draft states that if an individual who has already obtained a degree is found to have used illegal means to do so, the degree-granting institution must revoke the degree certificate. This decision should be made following a review by the degree evaluation committee.
House dust mites surround us. Burrowing cheerfully into our pillowcases, rugs and furniture, the mites feast on our dead skin cells, breaking them down into small particles they can digest.
Now that your skin is crawling, relax. If you’re like most people, you will never know they are there.
An unlucky minority, however, is very aware of dust mites. Some of these unfortunate folks have a simple dust allergy. But others have an additional condition called atopic dermatitis, often referred to as eczema. They react to the presence of dust — or rather, dust mites — with hideous itching and redness. It wasn’t totally clear what, exactly, caused people with dermatitis to react so badly to dust mites.
It turns out that these people react not to the dust mite, but to its dinner — to the breakdown products of the person’s own skin. The finding helps explain why people with atopic dermatitis react so badly to dust mites, and it provides several new options to help treat the itch. It also resolves a decade-long debate in dermatology — why people with dermatitis are scratching in the first place.
Inside out vs. outside in Atopic dermatitis is known for producing red, cracked and dry skin and, of course, the itching. People usually get diagnosed in childhood. Sometimes it goes away as kids get older, but it still affects between 9 and 30 percent of adults in the United States. Patients with dermatitis who react to dust are told to avoid dusty places and use special pillowcases. For the worst outbreaks, they are often prescribed a steroid cream. In some cases, they can end up in the hospital.
But what causes the itch in the first place? For the past 10 years, scientists have been scratching away at two hypotheses — one called “inside out,” and the other called “outside in.”
The “inside out” hypothesis came first, explains Graham Ogg, a dermatologist with the Medical Research Council Human Immunology Unit at the University of Oxford. The idea was that the immune system was overreacting to normal things: Dermatitis was an inside problem with the immune system itself.
In 2006, however, researchers reported in Nature Genetics that deficiencies in a protein called filaggrin were associated with atopic dermatitis. Now, it’s estimated that 20 to 30 percent of people with atopic dermatitis are also deficient in filaggrin, a protein in the outermost layer of the skin.
“It’s important for moisturizing the skin, keeping the skin hydrated,” explains Ogg. If people with dermatitis are deficient in filaggrin, then “the primary problem isn’t the immune system, it’s the barrier function in the skin.” If the barrier breaks down, more irritants can get in, prompting the immune response and the intolerable itch. So, the “outside in” hypothesis was born. In this view, the immune system wasn’t overreacting; instead it was reacting properly to the avalanche of aggravations it was faced with.
But what if these two hypotheses weren’t at odds, Ogg wondered, and instead were two sides of the same coin? To find out, Ogg and his group began by looking at a molecule called CD1a. This molecule is produced in the skin, and specializes in presenting bits of foreign matter to T cells — the immune system responders that mount attacks against foreign invaders.
It turns out that the CD1a molecules responded to extract-of-house-dust-mite — the delightful concoction that people get scratched with when they are tested for a dust allergy. And when they react, it’s because of CD1a molecules.
To find out if people with dermatitis had more CD1a than people without the condition, the scientists used suction to give eczema sufferers and healthy volunteers large blisters on their arms. The blisters were harvested for their skin and blood cells. And in patients with atopic dermatitis, those skin and blood cells were stuffed with CD1a, far more than in healthy controls.
But what was the CD1a reacting to? Usually CD1a senses fat molecules, presenting bits of them to the immune system to prep it for attack. Ogg and his group assumed that if they analyzed house dust mites, they would find the lipid or fat responsible. Not quite. Instead, they found a protein called phospholipase A2. Phospholipase is an enzyme that dust mites produce that breaks down skin cells, producing fat molecules the mites can digest. CD1a, it turns out, responds to those lipids — reacting to the house dust mite’s dinner. Reacting, really, to the breakdown products of human skin.
This seems like support for the “inside out” hypothesis. CD1a is part of the immune system, and the immune system does seem to be over-reacting.
Filaggrin also had a role to play. The protein doesn’t just create a barrier to keep the skin moisturized — it’s also anti-inflammatory, Ogg’s group showed. If a skin sample was challenged with essence of dust mite, adding filaggrin could damp down the immune response. But eczema patients with low or no filaggrin had no defense. Their skin was more permeable, and there was nothing to stop the inflammation. The “outside in” hypothesis —the idea that the barrier function is the broken part of the system – is true too. Ogg and his colleagues report their findings February 10 in Science Translational Medicine.
“It links together the observations very nicely,” says Muzalifah Haniffa, a dermatologist at Newcastle University in England. It never was a matter of “inside out” or “outside in.” The two are inextricably linked.
Eat like a dust mite, sting like a bee? So, to recap: As dust mites chow down on human skin, they cause damage to the cells. People with dermatitis have immune systems that detect the products of the damage and react, causing itching and pain. Filaggrin, when present, can tamp down the response. But when absent, nothing stops the itch.
The study shows filaggrin is far more than a simple barrier protein. Instead it directly affects immune responses in the skin, something that’s never been seen before, Haniffa notes.
This isn’t the first time that Ogg’s group has come across phospholipase A2. “Bee venom also contains phospholipase. In fact it contains massive amounts,” Ogg explains. Knowing that bee venom and dust mites have something in common helps scientists to understand one of the ways that the immune system senses damage to skin — and gives them another option to consider for treatment.
Right now, clinical trials are focused on stopping the inflammatory proteins produced further down the line. But, Haniffa says, scientists might try methods to increase the amount of filaggrin in the skin — beefing up the barrier against dust mite incursions and reducing the immune response at the same time. Other drugs or creams could target phospholipase A2, inactivating it. Without phospholipase, dust mites wouldn’t be able to break down skin cells, halting any immune reaction.
And that means we can hope for a new day. One with, hopefully, no itch.
Curves tend to put the brakes on human runners — especially those wearing prosthetics.
When navigating curves, runners must exert centripetal force to change directions, while countering the force of gravity vertically as well. They sacrifice speed in the process, and studies suggest that, in experienced sprinters, the inside leg generates less force on a curve than the outside leg.
In general, the passive, J-shaped prosthetics worn by amputee runners prevent them from generating as much force as a human ankle, and they compensate by swinging their legs faster. Researchers at University of Colorado at Boulder’s Applied Biomechanics Lab wanted to see how the inside-outside phenomenon played out in Paralympic sprinters. The team recorded and analyzed footage of Paralympic runners with above-the-ankle amputations and of non-amputee runners running clockwise and counterclockwise on a track. Sprinters ran 3.9 percent slower with their prosthetic on the inside compared with the outside of the curve, the team reports March 16 in the Journal of Experimental Biology. Amputee runners also dropped their stride frequency when their prosthetic limb was on on the inside of the curve, which may compound the problem of the prosthetic limb generating less force against the ground than a regular ankle.
Paralympic races always run counterclockwise, and the findings suggest that this may put left-leg amputees at a disadvantage.
Though science and art are vastly different disciplines, one can shed light on the other. That connection is on display in a recolorized version (above) of Vincent van Gogh’s The Bedroom.
The colors in the original work, a version painted in 1889, have faded over time. For an exhibit on display through May 10 at the Art Institute of Chicago, conservation scientist Francesca Casadio and colleagues conducted a number of tests to reveal the pigments van Gogh used.
A macro X-ray fluorescence scanner gave scientists a broad picture of the elements and minerals in the paint. A technique called surface-enhanced Raman spectroscopy — which uses laser light to make molecules vibrate in a way that betrays their identity — gave clues to other pigments in the paint. Finally, a microscopic sample taken from the painting (right) was especially revealing: The underside divulged the original purple color of the walls.
Casadio and colleagues then worked with a color theorist to simulate van Gogh’s paints, and with conservators and curators to create a digital version of the original painting that brings back “the emotional landscape of van Gogh,” Casadio says. “It’s a visualization that is not arbitrary; it’s informed by the science. But there’s still a process where you have to have the interpretive eye of those who know the artist.” The recolorization is on display through May 10 at the Art Institute of Chicago in an exhibit that for the first time brings together the three versions of The Bedroom that van Gogh painted in 1888 and 1889.
Before and after The original version of “The Bedroom” (left) has faded over time. The recolorized version (right) returns the pale violet hue of the walls and the redness in the floor tiles.
New cancer-fighting nanoparticles deliver results — and status reports.
Tiny biochemical bundles carry chemotherapy drugs into tumors and light up when surrounding cancer cells start dying. Future iterations of these lab-made particles could allow doctors to monitor the effects of cancer treatment in real time, researchers report the week of March 28 in the Proceedings of the National Academy of Sciences.
“This is the first system that allows you to read out whether your drug is working or not,” says study coauthor Shiladitya Sengupta, a bioengineer at Brigham and Women’s Hospital in Boston. Each roughly 100-nanometer-wide particle consists of a drug and a fluorescent dye linked to a coiled molecular chain. Before the particles enter cells, the dye is tethered to a “quencher” molecule that prevents it from lighting up. When injected into the bloodstream of a mouse with cancer, the nanoparticles accumulate in tumor cells and release the drug, which activates a protein that tears a cancer cell apart. This cell-splitting protein not only kills the tumor cell, but also severs the link between the dye and the quencher, allowing the nanoparticles to glow under infrared light.
Previous techniques could track drugs entering tumors, but that “doesn’t necessarily tell you whether the drug is working or not,” says study coauthor Ashish Kulkarni, a bioengineer at Brigham and Women’s and at Harvard Medical School. The team tested the nanoparticles in mice that each had two types of tumor: one resistant to the drug in the particles and one responsive to the drug. Drug-sensitive tumors glowed around five times as intensely as the resistant tumors. Results were swift, with tumors lighting up in eight to 12 hours. Replacing the particles’ cancer drug with antibodies that summoned the body’s tumor-fighting defenses allowed the team to test the nanoparticles as immunotherapy agents. In this case, tumors lit up after five days, reflecting an initial lag time of immunotherapy compared with chemotherapy.
These nanoparticles are a proof of concept, Sengupta says. Next steps include redesigning the nanoparticles using clinically approved materials and dyes that would be easier to track in the human body with the use of an MRI machine. But such imaging chemicals can be toxic, which could pose a problem for the nanoparticle design, says cancer nanotechnologist Mansoor Amiji of Northeastern University in Boston. Dyes should be cleared from the body as quickly as possible, while the drug they’re paired with might take weeks to work. But the study’s focus on detecting drug performance in real time is very important, and demands further study, Amiji says. “There’s tremendous need, especially as we think about personalizing cancer therapies.”
