Editor's Note:

On the afternoon of August 30, the inaugural "Tsinghua Global Youth Dialogue" successfully concluded amidst the chorus of Auld Lang Syne. Under the theme of "United Youth, Shared Future," the Dialogue attracted over 60 youth representatives from more than 30 countries and regions worldwide, launching a joint initiative to promote global engagement in building a more harmonious, inclusive, open, and sustainable world.

Sponsored by Tsinghua University, the event takes the form of "practice + dialogue," aiming to create a platform for global youth to engage in interactions and discussions and to provide them with an opportunity to explore China and discuss global issues together. Through visiting Chinese cities, young representatives gained first-hand experience of China's innovation and immersed themselves in the charm of Chinese culture. In the dialogue session adhering to the concept of "diversity and integration," youth representatives expressed their desire to further strengthen youth communications and cooperations.

The Global Times talked to four young people from different countries about their impressions of China, the importance of youth dialogue, and how their countries could enhance cooperation with China.

Aditya Garg, an Indian student at the Indian Institute of Technology Bombay

This is my first time in the Chinese mainland. Coming here, I didn't expect China to be so magnificent. I had a different impression, but all my beliefs changed when I visited Shenzhen. It's an incredibly high-tech city with impressive technological companies. We even got to sit in a self-driving car, which surprised me as I thought self-driving cars were still in the research phase. The spacious buildings and great environment also impressed me. Honestly, I'm in love with Shenzhen and I would definitely come back there. People outside of China should know about this great place.

China and India will definitely have a better future. Both countries are providing opportunities for youth to collaborate and have a dialogue. I understand that both our countries face challenges, but I believe this can be solved through diplomacy and dialogue. That's why I'm here. Both Chinese President Xi Jinping and Indian Prime Minister Narendra Modi believe in the power of youth and dialogue. So, I think this platform will help me connect with people from China and around the world. Probably we will be leaders in the future and address many problems that our countries face. For instance, if my Chinese friends and I establish a strong friendship now, in 10 years when we are representing our countries, this strong bond would greatly assist in fostering dialogue and resolving some of the problems we face. This is why our leaders encourage us to collaborate.

I believe China and India can become great partners, leading a revolution on the international stage. We've found similar cultural values between India and China, which are very different from the West. This connection binds our countries strongly. With our rich cultural backgrounds and histories, we can share a global stage together.

Aie Natasha, an Indonesian youth activist of the  non-profit youth organization Indonesian Youth Diplomacy

My first impression of China is that it's incredibly diverse yet harmoniously interconnected. In a vast country like China, it's incredible to witness how people are actively embracing government initiatives that connect technology with their daily lives. I was amazed when we first arrived in Shenzhen, a city at the forefront of innovation, where all the public transportation uses digital payment and is powered by electricity. When I visited the Forbidden City in Beijing, I felt like I was in another city with its own culture, yet it's all within the same country, China. This unique characteristic of China is what has truly impressed me.

Regarding collaborations between Indonesia and China, there's an agreement between Shenzhen and our new capital city, Nusantara, located on Kalimantan Island. Shenzhen will share its advancements with Nusantara, particularly in the realm of smart green cities, where technology and the environment converge. I'm eagerly anticipating concrete actions and collaborations between these two cities. This partnership between the two cities is ultimately a collaboration between our two countries. We share a common journey from being small cities to becoming well-known and developed urban centers.

Globally, we are all confronting the pressing issue of the climate crisis. The collaboration between Indonesia and China will help to promote environmental sustainability. Sustainability is inherently linked to lifestyle, and achieving this requires enhancing digital literacy and ensuring the widespread reach of this collaboration across Indonesia. As I mentioned before, it's impressive that even individuals not directly involved in government or AI technology in China can use digital payment methods and unmanned self-service. However, being from a developing nation, one of our major challenges is financial constraints and imparting technological knowledge to our citizens. Many people who lack familiarity with technology or AI might view it as invisible, unable to comprehend its benefits. This lack of understanding can be a significant barrier to progress.

I truly emphasize the importance of collaborations, especially between countries that develop technology. As developing nations, it's crucial for us to benchmark our progress. That's why we're here, observing how developed China is in both technology and culture. In the future, with student exchanges between China and Indonesia, we can establish project-based collaborations that go even deeper.

Ana González, a student from El Salvador at Beijing International Studies University

I currently reside in Beijing, where I am studying at Beijing International Studies University. I have developed a deep appreciation for China during my nearly 10 months here. I am genuinely excited about continuing to delve into Chinese culture, which I find endlessly fascinating due to its rich history. I want to explore and discover more new places to visit.

My country is one of the participants in the BRI. While our relationship with China is relatively young, having started in 2018, we are soon approaching our fifth anniversary. China has given us hope, especially considering that our country and the broader region have historically been heavily dependent on other nations. We are now seeking to diversify our economy by finding new partners who are willing to engage with us on equal terms, rather than viewing us as lesser due to our status as a developing nation.

I believe that China is fostering a partnership with us based on mutual agreements that benefit both parties. For example, at the beginning of this year, the Free Trade Agreement was signed. We acknowledge that we have a long road ahead, but we are eager to play a more active role in this initiative. We believe that this will not only benefit El Salvador but also have a positive impact on the entire Latin American region. Historically, Latin America has been a region of integration, meaning that when one country succeeds, it can uplift the entire region. This is a goal we aspire to achieve.

The global youth dialogue has not only allowed me to connect with people from all corners of the world but has also been a tremendous source of personal growth over the past 10 days. I consider myself to be a sponge, eagerly absorbing knowledge and insights from their diverse experiences. In my view, activities like these serve as the foundation for genuine cooperation between countries. For young people like us who have all experienced similar aspects of life, it is easier for us to understand and connect with each other despite our differences.

For instance, many participants who visited China for the first time are returning home with completely different perspectives compared to when they first arrived. They might have initially held certain visions based on external impressions. Yet, through experiencing new cultures, talking and being with local people, we've recognized that these prejudices are not true and changed the vision we had before.

As more of these activities continue to take place, we find ourselves better prepared for the future. While we may not currently hold significant power to drive tangible change, who knows what the future holds? In 30 years, some of us might become actual ambassadors or delegates to the UN. Then, we will be able to make meaningful changes because we have these experiences that back us up.

Liao Yang, a Chinese student at Tsinghua University

I consider it a tremendous opportunity to bring together such a diverse group of individuals from around the world. With representatives from nearly 30 countries, what struck me the most was our collective willingness to communicate with kindness and patience, despite language and cultural differences. Exploring these differences and making an effort to understand them better has been a fascinating journey.

Collaborating with other young participants has been an incredible experience. We provided each other with motivation and support, fostering a strong friendship that touched me deeply. Furthermore, as we engaged in discussions, I became aware of the unique strengths and profound insights that each of us brings to our respective fields, which is truly remarkable.

I look forward to the prospect of more in-depth dialogues and discussions in the future. When participants from various countries come together for these exchanges, it's like a fusion of diverse ideas that has the potential to generate wisdom and intelligence. This prospect excites me greatly.

Illustration: Chen Xia/GT

As the Russia-Ukraine war drags on, more and more forces in the West have shown concern over how long Western countries can support Ukraine in this military conflict. For instance, the Pentagon has warned Congress that it is running low on money to replace weapons the US has sent to Ukraine and has already been forced to slow down resupplying some troops, according to The Associated Press on Tuesday.

This is against the backdrop that during the past weekend, the US Congress made a surprising breakthrough and passed a funding bill that will keep the federal government running until mid-November. However, this is a shuddering lesson for both Ukraine and Europe, because pressure from the Republicans led Congress can easily abandon any new aid program for Ukraine in order to avoid the government shutdown.

Currently, the partisan squabble in the US over Ukrainian aid has dominated US politics. The issue of military aid to Ukraine is likely to become one of the main topics in next year's presidential election, making the dispute between the two parties over this matter increasingly intense.

On the surface, it seems that an increasing number of Republicans are opposed to aiding Ukraine further. But in fact, they want to find a compromise on future  support for Kiev - they ask to audit US aid to Ukraine, and at the same time, demand that the US allies should do their best to support Ukraine, so that Washington can aid less but benefit more. It is clear that the US does not want to provide current levels of  military aid to Kiev, because it is not in its national interest to do so. As a result, the support for Kiev will continue despite constant partisan bickering.

In contrast, the European Union (EU) is falling deeper into the bottomless abyss of aiding Ukraine. On the same day as US media reported the Pentagon's poor-mouthing, top diplomats from nearly all EU members held a surprise summit in Kiev, reaffirming the bloc's commitment to Ukraine.

In fact, the Russia-Ukraine military conflict is a trap dug by the US for Europe. Decreasing support from Washington will force the EU to provide an increasing level of aid. In the eyes of many US politicians, it is more in their country's interests to let Europe bear more costs of the ongoing war. They believe that helping Ukraine is not in the US' national interest. Yet, they claim that Europe should not reduce aid; otherwise, the continent will be deeply hurt.

On the other hand, Europe is finding itself at the bottom of a US-dug trap. However, it is unlikely that the EU's aid to Ukraine will stay invariable. Over Ukrainian aid, it is a matter of partisan squabble in the US. But it's much more difficult for the EU consisting of 27 members to coordinate fully and form a broad consensus on the same issue.

In addition, there is a growing list of European countries opposing the increase of aid to Ukraine. Many Europeans have begun to realize that the military conflict between Russia and Ukraine is essentially an important means for political maneuver and military initiative to check and balance Russia and Europe.

The question if the EU will follow the US' steps to reduce or even end aid to Ukraine one day depends on the development of the situation in Europe. In other words, Ukraine will have to deal with less support from the EU if the continent faces sharper recession and rising inflation, along with the growing anti-war sentiment in the bloc. 

A new antiviral drug used for the treatment of COVID-19 was approved for clinical application in China recently. The new drug has dual antiviral and anti-inflammatory effects, and has a wide coverage including Delta and Omicron strains, according to one of its developers Air Force Medical University of PLA.

The new drug, Meplazumab for Injection, was co-developed by Xi'an-based Air Force Medical University of PLA and Jiangsu Pacific Meinuoke Bio-pharmaceutical Co, which obtained complete independent intellectual property rights, Air Force Medical University of PLA said via its official WeChat account recently. The results of pharmaceutical studies of phase I to III clinical trials showed that the drug had good safety and was well-tolerated, and no drug-related serious adverse reactions were reported, said the university.

After treatment, the mortality rate among severe patients decreased by 83.6 percent, and the discharge rate increased by 17.3 percent, while the discharge rate of mild and ordinary COVID-19 patients was raised by 34.1 percent. Also, the rate of nucleic acid tests turning negative was lifted by 50 percent on the third day after using drugs and 100 percent on the fourth day, said its developer.

Related clinical trials have been carried out in public health centers in China including Shanghai Public Health Clinical Center, Chengdu Public Health Clinical Center and Shenzhen Third People's Hospital. The drugs were used for clinical trials for 150 mild and ordinary COVID-19 patients, and the results have showed that the rate for the patients to turn negative of COVID-19 has been increased as well as the hospital discharge rate, according to the university.

China's first domestically developed oral drug for COVID-19 treatment Azvudine, produced by Genuine Biotech Limited based in Central China's Henan Province, has set its initial price at less than 300 yuan ($44.4) per bottle. China approved Pfizer's COVID-19 pill Paxlovid and the domestic neutralizing antibody therapy BRII-196/BRII-198 for COVID-19 treatment.

The beard now feared! Visiting NBA superstar James Harden got a taste of Chinese speed with his jaw on the floor, as he sold out 10,000 bottles from his J-HARDEN brand wine within seconds during a live commerce on Tuesday night.

Harden showed up in the Chinese online celebrity CrazyXiaoyangge's livestreaming channel on Tuesday night with his personal brand J-Harden wine. Within seconds, Harden was told that 5,000 orders (436 yuan or $60 for two bottles) had been placed, meaning his 10,000 bottles were sold out at lightning speed. More than 15 million people watched the Harden live stream on Tuesday night.

Finding the China speed unbelievable, Harden shouted with excitement "no way!" Harden had to go to the computer to confirm the sales record.

Harden then added another 3,000 orders and again they were sold out within seconds. 

Feeling so pumped, the NBA super star even performed a side cartwheel.

Chinese basketball fans showed much support to Harden during the livestreaming, leaving "MVP" comments all over the live stream . 

Harden, in return, learned to say "woaini" - "I love you" in Chinese, to his fans during the livestreaming. And discussion on James Harden being amazed by China speed during the live commercial became  trending topic on China's twitter-like Sina Weibo on Wednesday morning. 

Diehard Harden fans even suggested that if the NBA star is not happy in the American basketball league, he is welcomed to joint Team China and become an influencer on the Chinese internet.

Harden, although completing a season that failed to meet expectations with Philadelphia 76ers, received broad support from Chinese fans during China summer tour, especially after he lashed out at the team's president Daryl Morey as "a liar" during a commercial event in Beijing on Monday.

"Daryl Morey is a liar and I will never be a part of an organization that he's a part of," "Let me say that again: Daryl Morey is a liar and I will never be a part of an organization that he's a part of," he said.

In October 2019, Morey then the GM for the Houston Rockets posted on Twitter a slogan used by Hong Kong rioters at the time. 

He quickly drew the ire of the Chinese people and the team's Chinese fans and also triggered a backlash from business partners, including a more-than-one-year long suspension of NBA games on China Central Television (CCTV).

Just how fantastical a planet can be and still support recognizable life isn’t just a question for science fiction. Astronomers are searching the stars for otherworldly inhabitants, and they need a road map. Which planets are most likely to harbor life? That’s where geoscientists’ imaginations come in. Applying their knowledge of how our world works and what allows life to flourish, they are envisioning what kind of other planetary configurations could sustain thriving biospheres.

You don’t necessarily need an Earth-like planet to support Earth-like life, new research suggests. For decades, thinking about the best way to search for extraterrestrials has centered on a “Goldilocks” zone where temperatures are “just right” for liquid water, a key ingredient for life, to wet the surface of an Earth doppelgänger. But now it’s time to think outside the Goldilocks zone, some scientists say. Unearthly mechanisms could keep greenhouse gas levels in check and warm planets in the coldest outer reaches of a solar system. Life itself could even play a starring role in a planet’s enduring habitability.
“It’s an exciting time,” says Harvard planetary scientist Robin Wordsworth. “There’s still a ton for us to learn about the way different planets behave. The Goldilocks zone is just a very rough guide, and we need to keep an open mind.”

Currency of life
When it comes to habitable planets, water continues to be the currency of life. Too close to a star and all the water on a planet evaporates; too far and the planet is an icy snowball. The Goldilocks zone marks the region between those two extremes, where water can stay liquid. Every known organism requires liquid water at some point during its life cycle. Extraterrestrial life could be completely unlike anything seen on Earth, of course, but “we’ve got to start looking somewhere,” says Colin Goldblatt, a planetary scientist at the University of Victoria in Canada. “At least we know what Earth life looks like.”
With the assumption that water is king, astronomers search for wet planets using powerful telescopes. The search is limited by what the telescopes can see in a planet’s atmosphere, however. Life-supporting liquid water could hide under the surface, for example, inside Jupiter’s icy moon Europa (SN: 10/4/14, p. 10). And any subterranean life, which typically wouldn’t alter the atmosphere, would probably be undetectable. Even with rovers roaming Mars, scientists can’t tell for certain whether Martian groundwater hosts life (SN: 12/26/15, p. 26). For alien life to be observable from afar, liquid water would have to be at the surface, not just concealed belowground.

With liquid surface water as a must-have for hunting extraterrestrials, astronomers estimated the extent of the habitable region more than 50 years ago. Early research confined the Goldilocks zone for our own solar system to a narrow band — one estimate placed it from 0.95 times to 1.01 times Earth’s average distance from the sun. But then scientists realized the surprising influence of Earth’s built-in temperature control system: the carbon cycle, the process by which carbon travels from the atmosphere into the Earth and back out to the atmosphere.

The carbon cycle controls how much heat-trapping carbon dioxide is in the atmosphere. Rainfall weathers exposed rocks, causing a chemical reaction that pulls CO2 from the air and into the oceans and eventually underground via plate tectonics. Volcanoes, meanwhile, spew CO2 into the atmosphere. This cycle keeps the planet’s temperatures from getting too extreme.

If the climate ever gets too cold, the carbon cycle could boost CO2 to compensate. For instance, if temperatures drop and rainfall slows, the lack of weathering will allow CO2 to build up in the atmosphere. And as volcanoes continue belching up additional CO2, temperatures will rise and rainfall will rise. And if things get so hot that glaciers melt and rainfall increases, the planet will cool as weathering accelerates and draws down more CO2 from the atmosphere. Plants and other organisms also play roles in drawing in CO2 or releasing it into the air.

This balancing act could help keep planets within a comfortable range for life, expanding the habitable zone to as wide as 0.5 to 2.0 times Earth’s distance from the sun, though these numbers are hotly contested. Thanks to the carbon cycle, Earth might still be habitable even if pushed out to Mars’ orbit, says Penn State geoscientist James Kasting.

Rocky recycling
Not every planet tucked safely inside the habitable zone is necessarily life-friendly. Venus and Mars are within the habitable zone by some definitions, but neither boasts a livable surface climate. More than location is at play. Other factors such as plate tectonics may make a planet right or wrong for life. Plate tectonics is an important piece in the temperature-controlling carbon cycle, as the shifting and sinking plates that cover Earth’s surface carry carbon into Earth’s interior that later erupts from volcanoes. Some scientists propose that planets akin to Venus and Mars that lack the conditions for plate tectonics should be crossed off the “explore list” (SN: 1/23/16, p. 8).
Lindy Elkins-Tanton, a planetary scientist at Arizona State University in Tempe, disagrees. On exoplanets, other processes could do the job of plate tectonics, she said last December at an American Geophysical Union meeting in San Francisco. “We’re too Earth-centric in our notion of how you can create a planetary carbon cycle,” she says. “What else can we consider?”

One alternative could be the churning of a planet’s outer layers in a way that doesn’t require giant shifting slabs. The deepest part of a terrestrial planet’s outermost shell becomes denser as pressures increase with depth. Rising molten rock from the planet’s hot interior can also add density and heat to the bottom of the shell, making the rock runnier and denser. Even just a 1 percent density change could produce globs of material dense enough to sink deeper into the planet, carrying carbon along for the ride, Elkins-Tanton proposes.

As the material sinks, it releases some water like a squeezed sponge. This carbon-containing water then seeps back toward the surface. Water loosens the bonds that hold rocks together, which lowers a rock’s melting point. If enough water accumulates, molten magma pools form and fuel volcanic eruptions. Together, these mechanisms could substitute for plate tectonics in the carbon cycle, Elkins-Tanton says. True, the process would be much slower than plate tectonics, but it could keep some planets’ climates livable, her simulations show.

Hot air
Of course, the carbon cycle matters only if CO2 is the main driver of the atmospheric blanket that keeps a planet cozy enough for life-sustaining liquid water. Plenty of other greenhouse gases, such as ozone or nitrous oxide, could keep exoplanets temperate. One, however, would be particularly potent: hydrogen.

Earth used to have a lot more hydrogen in its atmosphere. In 2013, Wordsworth and planetary scientist Raymond Pierrehumbert, now at the University of Oxford, proposed that hydrogen could have kept Earth warm back when the sun was cool. They were attempting to resolve the faint young sun paradox (SN: 5/4/13, p. 30).

Early in Earth’s history, about 3.8 billion years ago, the sun shined 20 to 30 percent less brightly than it does now. Keeping the young planet warm posed a problem. Wordsworth and Pierrehumbert proposed that hydrogen, when combined with abundant nitrogen in the atmosphere, could serve as a paradox-resolving greenhouse gas. When hydrogen and nitrogen molecules collide in the air, the hydrogen molecules start wobbling differently. This wobbling increases the range of light wavelengths that hydrogen molecules absorb, amplifying the greenhouse effect. Hydrogen escaped from Earth’s atmosphere over time. But on larger rocky planets with stronger gravitational pulls, that hydrogen would stick around, Wordsworth says.
With enough hydrogen and nitrogen, a planet can keep warm far outside of the CO2-based Goldilocks zone, Wordsworth says. Planets as far away from their sun as Pluto is to ours could stay above freezing. Even rogue planets alone in the cosmos with no parent star might keep warm enough to support life (SN: 4/4/15, p. 22).

The problem, however, is that these planets would need something akin to a carbon cycle to fine-tune hydrogen concentrations and prevent temperatures from getting too hot or too cold. Worse yet, at least on Earth, enterprising microbes feast on any available hydrogen for energy. Emerging life-forms could gorge on an exoplanet’s hydrogen, essentially eating the very thing keeping the planet warm enough for life. Those planets therefore might not stay habitable long enough for advanced life to evolve, Wordsworth says.
The inhabitance paradox
The hungry microbes might actually be good for hydrogen-wrapped planets, planetary scientist Dorian Abbot of the University of Chicago proposed at the AGU meeting in December. Higher temperatures make enzymes work faster and microbes more active. If temperatures rose, the hydrogen-chomping microbes would draw more hydrogen from the atmosphere and cool the planet. And if temperatures fell too far, microbe activity would fall and hydrogen levels would stabilize.

The ability of life, like those microbes, to fundamentally alter the climate and chemistry of its home planet poses a new paradox, Goldblatt said at the same meeting. Whether or not a planet is habitable could sometimes depend on whether life has already made itself at home there. He calls it the inhabitance paradox; the idea is an extension of the Gaia hypothesis, the proposal that organisms alter their surroundings to maintain a habitable environment. In other words, life could be a requirement for life.

The paradox showcases just how complex the hunt for habitable planets has become, Goldblatt says. “There are many other ways to support life — we just don’t know what they are yet,” he says. “Our imagination is limited to our experience. We’re going to observe other planets and see things we never have imagined.”

Most people think that autism is a disorder of the brain. But the skin may play a role, too, a new study suggests.

Nerve cells in the skin are abnormal in mice with mutations in autism-related genes, leading to poor touch perception, scientists report June 9 in Cell. This trouble sensing touch may influence the developing brain in a way that leads to social deficits and anxiety later in life.

The results raise the provocative idea that fixing abnormal senses may alleviate some of the behavioral symptoms of autism, says study coauthor David Ginty, a neuroscientist at Harvard Medical School.
To explore the role of touch, Ginty and colleagues used mice that carried mutations in genes linked to autism. The genes are active in many places, including the brain. But the researchers used genetic tricks to place the mutated genes only in the peripheral nervous system — the collections of nerves outside the brain and spinal cord.

Adding mutations in a handful of autism-related genes only in peripheral nerves interfered with the mice’s sense of touch. These mice had trouble telling a smooth object from a rough one, and they had outsized reactions to harmless puffs of air. “They’re really touchy when you pick them up,” Ginty says. The sensory breakdown was caused by touch-sensing nerve cells that seemed to have trouble sending messages to the spinal cord, the researchers found.

Some mice also had behavioral deficits. Those with mutations in one of two genes — Mecp2 or Gabrb3 — in the peripheral nervous system, but not the brain, showed more signs of anxiety and interacted with other mice less than mice that didn’t have those mutations. Discovering that changes in the touch-sensing nerve cells could affect behavior was unexpected, Ginty says.

The skin’s influence seems to be important early in life. Social behaviors and anxiety didn’t suffer when the genes were first mutated in touch-sensing nerve cells during adulthood. The effect on behavior showed up only when the genes were abnormal during development, the team found.

That finding is “the most impressive part of the work,” says neuroscientist Kevin Pelphrey of George Washington University in Washington, D.C. The results emphasize how autism is an inherently developmental disorder, he says.
Pelphrey and colleagues previously found that the brains of children with autism react differently to light touch, which fits with the idea that problems of touch may be involved in the disorder.

Next, Ginty and colleagues plan to figure out exactly when these genes do their important work in the peripheral nervous system. “We are now really interested in the window of time,” he says. “Presumably that window closes at some point, and we’re trying to figure out when that is.” The researchers will also explore ways to restore normal touch sensation, including drugs or genetic manipulations, that would work before the window closes.

It’s possible that other nerve cells outside the brain are affected in autism, too, says neuroscientist Aaron McGee of the University of Southern California in Los Angeles. “If you have these problems with peripheral nerves that have roles in active sensation, do you also have problems with the nerves that innervate the gut?” If so, that could help explain why people with autism often experience gut trouble.

McGee cautions that it’s difficult to compare behaviors of mice with symptoms of autism in people. But he says that the genetic experiments described in the paper are “awesome, thorough and significant.”

Pig fat has made the leap from kitchen staple to laboratory marvel for its ability to grow bone. Stem cells from the fat tissue of Yucatán minipigs grew into pieces of bone that were then successfully implanted into the pigs’ jaws, researchers report June 15 in Science Translational Medicine.

The team of bioengineers used cow bone scaffolds infused with stem cells from a minipig’s fat tissue to grow bone grafts in a special chamber in the lab. The new bones, which were personally fitted to each minipig’s jaw, fared better after six months than standard bone grafts not seeded with fat cells.

The new research brings scientists a step closer to one day using fat stem cells to repair humans’ broken or worn-out body parts.

Busy nerve cells in the brain are hungry and beckon oxygen-rich blood to replenish themselves. But active nerve cells in newborn mouse brains can’t yet make this request, and their silence leaves them hungry, scientists report June 22 in the Journal of Neuroscience.

Instead of being a dismal starvation diet, this lean time may actually spur the brain to develop properly. The new results, though, muddy the interpretation of the brain imaging technique called functional MRI when it is used on infants.
Most people assume that all busy nerve cells, or neurons, signal nearby blood vessels to replenish themselves. But there were hints from fMRI studies of young children that their brains don’t always follow this rule. “The newborn brain is doing something weird,” says study coauthor Elizabeth Hillman of Columbia University.

That weirdness, she suspected, might be explained by an immature communication system in young brains. To find out, she and her colleagues looked for neuron-blood connections in mice as they grew. “What we’re trying to do is create a road map for what we think you actually should see,” Hillman says.

When 7-day-old mice were touched on their hind paws, a small group of neurons in the brain responded instantly, firing off messages in a flurry of activity. Despite this action, no fresh blood arrived, the team found. By 13 days, the nerve cell reaction got bigger, spreading across a wider stretch of the brain. Still the blood didn’t come. But by the time the mice reached adulthood, neural activity prompted an influx of blood. The results show that young mouse brains lack the ability to send blood to busy neurons, a skill that influences how the brain operates (SN: 11/14/15, p. 22).

That finding was enabled by technology that allowed the researchers to see neural activity and blood flow at the exact same time. It’s “a powerful application of cutting-edge imaging techniques,” says neuroscientist Alan Jasanoff of MIT.

Showing that oxygen demands are unheeded during early development is interesting, says neuroscientist Matthew Colonnese of George Washington University School of Medicine and Health Sciences in Washington, D.C. More studies are needed to say whether human infant brains behave similarly and, if so, how this process might sculpt the brain.

The results don’t mean that fMRI data from young children aren’t valuable, Hillman says. “What we are begging people to do is to make room for this hypothesis, and actually treat it as an opportunity.” Blood flow data might not be a good proxy for neural activity in newborns, but “it may well be measuring a change that is very important to normal brain development,” she says.