Scientists with the University of Chicago have demonstrated away to create infrared light using colloidal quantum dots.The researchers said the method demonstrates great promise;the dots are already as efficient as existing conventional methods,even though the experiments are still in early stages.The dots could someday form the basis of infrared lasers as well as small and cost-effective sensors,such as those used in exhaust emissions tests or breathalyzers.“Right now the performance for these dots is close to existing commercial infrared light sources,and we have reason to believe we could significantly improve that,”said Philippe Guyot-Sionnest,a professor of physics and chemistry at the University of Chicago,member of the James Frank Institute,and one of three authors on the paper published in Nature Photonics.“We’re very excited for the possibilities.”The right wavelength Colloidal quantum dots are tiny crystals—you could fit abillion into the period at the end of this sentence—that emit different colors of light depending on how big you make them.They’re very efficient and easy to make and are already being used in commercial technology;you might already have bought aquantum-dot TV without knowing it.However,those quantum dots are being used to make light in the visible wavelength—the part of the spectrum humans can see.If you wanted quantum dot light in the infrared wavelength,you’ve mostly been out of luck.But infrared light has alot of uses.In particular,it is very useful for making sensors.If you want to know whether harmful gases are coming out of your car exhaust,or test whether your breath is above the legal alcohol limit,or make sure methane gas isn’t coming out of your drill plant,for example,you use infrared light.That’s because different types of molecules will each absorb infrared light at avery specific wavelength,so they’re easy to tell apart.“So acost-effective and easy-to-use method to make infrared light with quantum dots could be very useful,”explained Xingyu Shen,a graduate student and first author on the new study. 查看详细>>

The U.S.Department of Energy has announced the renewal of the Midwest Integrated Center for Computational Materials(known as MICCoM)for another three years at$3 million per year.Founded in 2015,the center is headquartered at Argonne National Laboratory.Partnering universities include the University of Chicago,University of Notre Dame and University of California,Davis.“The MICCoM team has been at the forefront of developing simulation methods and codes and solving cutting-edge materials science problems,”said center director Giulia Galli,a senior scientist in Argonne’s Materials Science Division and professor in the Pritzker School of Molecular Engineering and the Department of Chemistry at the University of Chicago.The use of theory and computation plays acentral role in the design of new materials for applications in diverse fields.The MICCoM mission is to apply theoretical methods and software to the understanding,simulation and prediction of the properties of materials at the atomic and molecular scale.To that end,MICCoM develops and disseminates ahost of interoperable computer tools.It also establishes the validity of theoretical models and codes for determining the characteristics and behavior of materials.Another part of its mission is providing searchable materials data that are reproducible with small margins of error.This is an increasingly pressing need in the age of artificial intelligence and machine learning.“In the last eight years,MICCoM has positioned itself to be asustained innovation factory for new simulation strategies to solve materials science problems,”Galli said.“We have also been providing exemplary open-source software,data and validation procedures to the scientific community.”At its founding in 2015,the Center focused on new materials for energy conversion,including nanoparticle-based solids for the conversion of sunlight into energy.Starting in 2019,MICCoM began working on the modeling and simulation of materials for quantum technologies.This strategic emphasis presents an opportunity to leverage the extraordinary behavior of nature‘s smallest scales to discover groundbreaking materials for quantum computing,sensing and communication.In the next three years,MICCoM will also emphasize energy saving by designing materials for low-power microelectronics.There is an urgent need for new computational pathways to materials and devices that will lead to more energy-efficient microelectronics.This research endeavor not only supports the U.S.leadership in microelectronics research but also could reinvigorate the semiconductor manufacturing industry. 查看详细>>

Physicists now have abrand-new measurement of aproperty of the muon called the anomalous magnetic moment that improves the precision of their previous result by afactor of 2.An international collaboration of scientists working on the Muon g-2 experiment at the U.S.Department of Energy’s Fermi National Accelerator Laboratory announced the much-anticipated updated measurement on Aug.10.This new value bolsters the first result they announced in April 2021,and sets up ashowdown between theory and experiment over 20 years in the making.“We’re really probing new territory.We’re determining the muon magnetic moment at abetter precision than it has ever been seen before,”said Brendan Casey,a senior scientist at Fermilab who has worked on the Muon g-2 experiment since 2008.Beyond the Standard Model Physicists describe how the universe works at its most fundamental level with atheory known as the Standard Model.By making predictions based on the Standard Model and comparing them to experimental results,physicists can discern whether the theory is complete—or if there is physics beyond the Standard Model.Muons are fundamental particles that are similar to electrons but about 200 times as massive.Like electrons,muons have atiny internal magnet that,in the presence of amagnetic field,precesses or wobbles like the axis of aspinning top.The precession speed in agiven magnetic field depends on the muon magnetic moment,typically represented by the letter g;at the simplest level,theory predicts that gshould equal 2.The difference of gfrom 2—or gminus 2—can be attributed to the muon’s interactions with particles in aquantum foam that surrounds it.These particles blink in and out of existence and,like subatomic“dance partners,”grab the muon’s“hand”and change the way the muon interacts with the magnetic field.The Standard Model incorporates all known“dance partner”particles and predicts how the quantum foam changes g.But there might be more.Physicists are excited about the possible existence of as-yet-undiscovered particles that contribute to the value of g-2—and would open the window to exploring new physics.Gordan Krnjaic,a theoretical particle physicist at Fermilab and the University of Chicago Kavli Institute for Cosmological Physics,told the New York Times that if the experimental disagreement with theory persisted,it would be“the first smoking-gun laboratory evidence of new physics.And it might well be the first time that we’ve broken the Standard Model.” 查看详细>>

At first glance,you may see aserene lake at sunset or delicate petals on awinter-blooming tree.But look closer at UChicago professor of chemistry Bozhi Tian’s artwork and you might notice these images don’t quite capture the world as it is.They meld scenes of nature with hints of technology,much as his research merges biological and synthetic systems.A materials scientist who works with semiconductors for biomedical applications,Tian designs devices to stimulate or modulate parts of the anatomy,such as the heart and neurons.One project his lab has been working on for almost eight years is asolar powered pacemaker.The team is also exploring technology to influence microbes,including an edible material that could modulate the gut microbiome,potentially helping to treat gastrointestinal ailments like inflammatory bowel disease.Tian’s research is inspired by the natural world:its shapes and textures and patterns.And that influence suffuses his artwork,often created in conjunction with his science:a riverscape with ananowire forest,a neural cell framed as asnowcapped mountain.These are created digitally,but Tian has been painting and drawing since childhood.Encouraged by his father,Tian started practicing calligraphy when he was 3.He branched out to painting at 6and started experimenting with design software at 15 or 16,when his father bought him his first computer.(Around that time,he was falling in love with chemistry and devoting more attention to science.)He still enjoys making analog art but finds it time-consuming.At Shanghai’s Fudan University,where Tian earned bachelor’s and master’s degrees in chemistry,his devotion to art and to science began to coalesce.He joined aresearch lab that designed and synthesized porous materials—orderly and geometrically structured with nanoscale pore size.Such structures exist in nature but not at the same scale,Tian says.The 2D and 3D arrangements fascinated him.“It’s essentially an art piece,”he thought.Both scientists and artists must be innovative and imaginative,says Tian,inspired in how they re-create their vision of the world.This multidimensional creativity is particularly evident in one of his lab’s new research directions,what he calls“synthetic reality.”The team is focusing on designing tissue-like materials,but not in the traditional tissue engineering sense(such as growing artificial organs or materials for direct medical use).“We’re thinking more broadly,”he says.Imagine incorporating organic tissue into your surroundings—an idea that struck Tian on arecent visit to the intensive care unit of Comer Children’s Hospital to meet with acollaborator.There it occurred to him that premature babies have physical and emotional needs that would have been met by their mothers’bodies,but they are treated inside what is basically abatting-lined box.Perhaps the team could create an environment like awomb.“We don’t really need reality,as long as it feels like reality,”he says.“That should be enough.”Likewise,some stringed instruments traditionally use gut string,made from animal intestines,which produces awarmer sound than steel.But asynthetic gut-like tissue might produce an equally beautiful tone.Reality:inspired by nature but made in alab.Tian believes that combining science and design is good business—it sells innovation through communication.“It helps motivate people,”he says,“bringing us together through storytelling.”But he admits that creating art is also asort of compromise.He finds illustration relaxing but sometimes feels guilty for neglecting his research.This way,he doesn’t have to choose. 查看详细>>

Sending an atomic clock onboard aspacecraft to fly close to the sun might be the trick to uncovering the nature of dark matter,suggests anew study published in Nature Astronomy.Dark matter makes up more than 80%of the mass in the universe,which we know because we can see its effects on galaxies and stars—but so far,no one has been able to directly detect it,despite decades of experimental efforts.A group of scientists has proposed anew way to look for this mysterious dark matter,using the technology known as atomic clocks.Atomic clocks,which tell time by measuring the rapid oscillations of atoms,are already at work in space,enabling the Global Positioning System(GPS).These clocks are so precise that they will not lose even asecond of time in billions of years.This caught the attention of researchers,who thought they might be able to use this unique precision to detect dark matter."This is abeautiful synergy between particle theorists and aquantum expert,and we have been in contact with NASA solar probe researchers to realize this proposal,"said lead author Yu-Dai Tsai."There are many new exciting directions in the intersection of all these fields."The study,published Dec.5,was led by Tsai,who initiated the project at the University of Chicago and Fermilab and is now apostdoctoral researcher at the University of California,Irvine,along with collaborators University of Delaware physicist Marianna Safronova and Joshua Eby of the University of Tokyo and the Kavli Institute for the Physics and the Mathematics of the Universe.Constants of nature“Dark matter is one of the most important remaining mysteries in astronomy and cosmology,given its unknown and elusive nature,”explained Tsai.“If we could find dark matter and understand its properties,we can understand the evolution of our universe.”But because scientists are not even sure exactly what dark matter is and how it behaves,it’s been difficult to even design ways to find it.Consequently,scientists have come up with many theories of what dark matter could look like.One such theory is known as“ultralight”dark matter.If this ultralight dark matter exists the way the theory predicts it does,it should cause oscillations in the very constants of nature—such as in the mass of electrons or the strength of the electromagnetic force.This caught the attention of the scientists.They knew that atomic clocks use these constants of nature to operate—so any change in these constants of nature should show up in the functioning of the atomic clock.Specifically,atomic clocks—sometimes known as quantum clocks—operate by carefully measuring the frequency of photons emitted in transitions of different states in atoms.Ultralight dark matter in the vicinity of the clock experiment could modify those frequencies,as the oscillations of the dark matter slightly increase and decrease the photon energy.That would change how the clock ticks.To have the best chance of working,the scientists said,the clocks should be positioned close to the sun,where theory predicts that the dark matter should clump in ahalo.The technology to put their theory to the test already exists,the scientists said.The NASA Parker Solar Probe,operating since 2018,is the closest artificial spacecraft to the sun in human history.“The Parker Solar Probe is not returning to Earth,but the next-generation solar probes can carry aprecise quantum clock on board,”said Tsai.“Such aspace mission would have the ability to carry out our proposed study.”The Parker Solar Probe is named after the late great physicist at the University of Chicago,Prof.Eugene Parker,who has made significant contributions to solar physics."I was an associate fellow at the University of Chicago when we initiated the project,and Parker‘s pursuit inspired us on this project,”Tsai said."There are so many more exciting topics to explore,"Tsai continued."Beyond this work,space missions can also provide data for planetary defense.In our related works,we also utilize these data to study questions such as local dark matter density and the possibility of afifth force of nature beyond the Standard Model of Physics.Quantum sensors,including atomic clocks,can improve the precision of these measurements and provide us with stronger tests for fundamental physics." 查看详细>>

Respiratory syncytial virus,often called RSV,is acommon virus that can cause infections in the nose,throat,lungs and respiratory tract.Historically,almost all children are infected with RSV by age 2,and re-infections are common at all ages.RSV is aleading cause of hospitalization in infants.As of November 2022,cases of RSV and other respiratory illnesses—such as enterovirus,rhinovirus and parainfluenza—are surging throughout the United States,placing many pediatric hospitals at full capacity.If your child needs emergency care,it may be helpful to check your local hospital wait times as you consider your options for care.Why is RSV so bad this year?RSV infections declined significantly during the peak of the COVID-19 pandemic.Due to masking and social distancing measures,young children were not exposed to common germs during this time.As many return to schools and other public places without masks,germs and viruses are spreading as normal.However,with less built-up immunity,children are more vulnerable than usual.People can catch RSV more than once,but the first time achild has an RSV infection,they are generally sicker than they are the next time.Because of COVID-19 prevention measures,we have one and two year olds who are just now having their first RSV infection.This makes it even more important to pay attention to your child’s health,as well as those around them.What are common symptoms of RSV in infants and children?Common symptoms for RSV include:Runny nose Decreased appetite Coughing and wheezing Sneezing Fever Most people will only experience mild symptoms and recover after one to two weeks.However,symptoms can be more severe for high-risk individuals,including:Very young children Older adults Anyone with chronic health problems For premature babies,infants 6months or younger and children with weakened immune symptoms,RSV infection can lead to severe illness including bronchiolitis and pneumonia.Symptoms of RSV in infants,younger than 6months old,may include:A lack of hunger and activity Irritability Breathing problems How is RSV different from COVID-19,a cold,or the flu?RSV symptoms can be very similar to other contagious respiratory viruses.An RSV infection can often look very similar to acommon cold,in particular.RSV infection can come in stages,so be on the lookout if symptoms worsen.This is asign that you should contact ahealth care provider.How does RSV spread?The virus is highly contagious and can spread in avariety of ways,including:Droplets from asneeze or cough of an infected person coming into contact with your eyes,nose or mouth Touching asurface(like acounter)that is contaminated with the virus Making direct contact with the virus(such as kissing aloved one who has RSV)What can you do to prevent RSV from spreading?Thankfully,there are very important measures you can take to minimize the spread of RSV.You can avoid spreading RSV if you:Practice proper hand hygiene and wash your hands regularly.Stay home when you have symptoms and avoid close contact with others if either of you are infected.Cover your coughs and sneezes and dispose of used tissues right away.Disinfect hard surfaces that are used often,especially if they have been touched by someone who‘s feeling sick.Avoid touching your face. 查看详细>>

The coming decade is expected to bring averitable bonanza for the science of planets:space missions are scheduled to bring back samples of rock from the moon,Mars,the Martian moon of Phobos,and aprimitive asteroid.And scientists say there is anew technique for determining the age of rocks,meteorites,and even artifacts,that could help open up anew era of discovery.A group with the University of Chicago and the Field Museum of Natural History tested an instrument made by Thermo Fisher Scientific on apiece of aMartian meteorite nicknamed‘Black Beauty’and were able to quickly and precisely date it by probing it with atiny laser beam—a significant improvement over past techniques,which involved far more work and destroyed parts of the sample.“We are very excited by this demonstration study,as we think that we will be able to employ the same approach to date rocks that will be returned by multiple space missions in the future,”said Nicolas Dauphas,the Louis Block Professor of Geophysical Sciences at the University of Chicago and first author on astudy laying out the results.“The next decade is going to be mind-blowing in terms of planetary exploration.”Rock of ages Scientists have been using isotopes to estimate the ages of specimens for more than acentury.This method takes advantage of the fact that certain types of elements are unstable and will slowly turn into other types at aslow,predictable rate.In this case,scientists tap the fact that rubidium-87 will change into strontium-87—so the older the rock is,the more strontium-87 it will have.Rubidium dating can be used to determine the ages of rocks and objects that are billions of years old;it is widely used to understand how the moon,Earth,and solar system formed,to understand the magma plumbing system beneath volcanoes,and to trace human migration and trades in archaeology.Previously,however,the way to make this measurement would take weeks—and it would destroy part of the sample.To perform those tests with the conventional method,“you take your piece of rock,crush it with ahammer,dissolve the minerals with chemicals and use aspecial ultra-clean laboratory to process them,and then take it to amass spectrometer to measure the isotopes,”explained study co-author Maria Valdes,a postdoctoral researcher in the Robert A.Pritzker Center for Meteoritics and Polar Studies at the Field Museum of Natural History.But Thermo Fisher Scientific developed anew machine that promised to significantly cut the time,toxicity,and amount of sample destroyed in the process.It uses alaser to vaporize atiny portion of the sample—the hole created is the size of asingle human hair—and then analyzes the rubidium and strontium atoms with amass spectrometer that uses new technological advances to cleanly measure strontium isotopes. 查看详细>>

University of Chicago chemist Weixin Tang has received a2022 Packard Fellowship in Science and Engineering.Tang is one of 20 early-career scientists and engineers nationwide to receive the fellowship from the David and Lucile Packard Foundation.Tang,a Neubauer Family Assistant Professor in chemistry,will receive$875,000 over five years to support her research.Tang’s lab specializes in using chemistry-based tools to understand and alter biological processes.The Packard Fellowship will fund an initiative that seeks to create new ways to make therapeutic molecules with atechnique called directed evolution.Sometimes,as researchers seek treatments for diseases,they would like to make biomolecules that do not exist yet.For example,perhaps they want to design aprotein that flags cancerous cells to bring them to the attention of the immune system.Evolution is very good at creating such molecules,but in nature,the process can take centuries.Scientists instead hope to speed up the process by creating lab conditions that favor the development of the particular functions they’re looking for.However,most of the directed evolution work so far has used bacteria because they’re simple and easy to take care of.“The problem is,they tend not to produce things that function well in human bodies,”Tang explained.Tang reasoned that using mammalian cells instead would produce better results—but there is not yet an easily accessible system to do so.So she set out to make one:“We want to set up arobust system that allows us to evolve molecules within the system they’re supposed to work.”Rather than aiming at aspecific function,they hope to develop aplatform that any lab can use to create what they need,Tang said.“It’s bigger than asingle problem;we want to build atool that provides the basis for many wonderful new things,not just one,”she explained.Tang joined the University of Chicago in 2019.Her previous awards include the Searle Scholar Award and the National Institute of Biomedical Imaging and Bioengineering’s Trailblazer Award.The Packard Foundation established the fellowships program in 1988 to provide early-career scientists with flexible funding and the freedom to take risks and explore new frontiers in their fields.The Packard Foundation Fellowships Advisory Panel,a group of 12 internationally recognized scientists and engineers,evaluates the nominations and recommends fellows for approval by the Packard Foundation Board of Trustees. 查看详细>>

When avirus makes its way into aperson’s body,one of the immune system’s first responders is aset of pathogen-removal cells called macrophages.But macrophages are diverse;they don’t all target viruses in the same way.Researchers at the University of Chicago’s Pritzker School of Molecular Engineering have discovered that the type of macrophages present in aperson’s body might determine how likely they are to develop severe inflammation in response to COVID-19.Their study has been published in Nature Communications.“Clinicians know that COVID-19 can cause aspectrum of disease severity from mild to severe symptoms.Why some people,and not others,develop very severe disease has been amystery,”said Asst.Prof.Huanhuan Joyce Chen,who led the research with Qizhou Lian of the University of Hong Kong.“This is the first time anyone has linked the variation in symptoms to macrophages.”A better model for COVID-19 infection Studying the cellular and molecular effects of the SARS-CoV-2 virus has been challenging for researchers who usually turn to model organisms to mimic human diseases,because mice,rats,and many other animals don’t develop the same COVID-19 symptoms as people.That’s why,shortly after the COVID-19 pandemic began,Joyce Chen Lab harnessed human stem cells to study the virus. 查看详细>>

Primates are generally considered“smarter”than mice.But in asurprising finding,neuroscience researchers at the University of Chicago and Argonne National Laboratory have discovered that mice actually have more synapses connecting the neurons in their brains.In astudy comparing the brains of macaques and mice at the synaptic level,the researchers found that the primates had far fewer synapses per neuron compared to the rodents.Using artificial recurrent neural network modeling,the team was further able to determine that the metabolic cost of building and maintaining synapses likely drives larger neural networks to be sparser,as seen in primates versus mouse neurons.The results were published Sept.14 in Cell Reports.The research team,made up of scientists from the laboratories of David Freedman at UChicago and Narayanan“Bobby”Kasthuri at Argonne National Laboratory,leveraged recent advances in electron microscopy,as well as existing publicly available data sets,to compare the connectivity in both species.They chose to examine both excitatory and inhibitory synapses,as most previous research had focused on only excitatory synapses.Focusing on layer 2/3 neurons in the adult primary visual cortex made it easier to compare across species,as these neurons have distinct morphologies that are similar in both primates and mice.After reconstructing the microscopy images and measuring the shapes of 107 macaque neurons and 81 mouse neurons,the researchers identified nearly 6,000 synapses in the macaque samples and over 9,700 synapses in the mouse samples.Upon comparing the datasets,they found that primate neurons receive two to five times fewer excitatory and inhibitory synaptic connections than similar mouse neurons.“The reason why this is surprising is that it there’s this quiet sort of assumption among neuroscientists and,I think,people in general that having more neuronal connections means that you’re smarter,”said Gregg Wildenberg,a staff scientist in the Kasthuri lab.“This work clearly shows that while there are more total connections in the primate brain overall because there are more neurons,if you look on aper-neuron basis,primates actually have fewer synapses.“But we know that primate neurons can perform computations that mouse neurons can’t.This raises interesting questions,like what are the ramifications of building alarger neuronal network,like the ones seen in primates?”After uncovering this surprising finding,Wildenberg connected with Matt Rosen,a graduate student in the Freedman lab,hoping Rosen could bring his computational expertise to better understanding the discrepancy in synapse number and its possible cause.“We’ve had this expectation forever that the density of synapses in primates would be similar to what’s seen in rodents,or maybe even higher because there’s more space and more neurons in the primate brain,”said Rosen.“In light of Gregg’s surprising finding,we thought about why primate neurons would make fewer connections than expected.And we thought that perhaps it was driven by evolutionary forces—that perhaps the energetic costs associated with maintaining abrain might be driving this difference.So we developed artificial neural network models and trained them to do tasks while we gave them constraints inspired by the metabolic costs that are faced by actual brains,to see how that affects the connectivity that arises in the networks that result.” 查看详细>>