Every year,the South Asian monsoon season brings heavy rain to over abillion people in the Indian subcontinent between June and September.The rain falls in oscillations:Some weeks see 1to 4inches of water,while other weeks are mostly dry.Predicting when these dry and wet periods will occur is critical for agricultural and urban planning,enabling farmers to know when to harvest crops and helping city officials prepare for flooding.However,while weather predictions are mostly accurate within one or two days,precisely predicting the weather aweek or month out is very difficult.Now,a new machine-learning-based forecast has been shown to more accurately predict the South Asian monsoon rainfall 10 to 30 days in advance,a significant improvement on current state-of-the-art forecasts that use numerical modeling rather than artificial intelligence to make predictions.Understanding monsoon behavior is also important because this type of rainfall is amajor atmospheric feature in the global climate.The research was led by Eviatar Bach,the Foster and Coco Stanback Postdoctoral Scholar Research Associate in Environmental Science and Engineering,who works in the laboratories of Tapio Schneider,the Theodore Y.Wu Professor of Environmental Science and Engineering and JPL senior research scientist;and Andrew Stuart,the Bren Professor of Computing and Mathematical Sciences.A paper describing the new method appears in the Proceedings of the National Academy of Sciences on April 1."There is alot of concern about how climate change will affect the monsoon and other weather events like hurricanes,heat waves,and so on,"Bach says."Improving predictions on shorter timescales is an important part of responding to climate change because we need to be able to improve preparedness for these events."Predicting the weather is difficult because the atmosphere contains numerous instabilities—for example,the atmosphere is continually heated from the earth below,leading to cold,denser air above hotter,less dense air—as well as instability caused by uneven heating and Earth‘s rotation.These instabilities lead to achaotic situation in which the errors and uncertainties in modeling the atmosphere‘s behavior quickly multiply,making it nearly impossible to predict further into the future. 查看详细>>

Now,the team has reinvented the technique to allow for printing objects athousand times smaller:150 nanometers,which is comparable to the size of aflu virus.In doing so,the team also discovered that the atomic arrangements within these objects are disordered,which would,at large scale,make these materials unusable because they would be considered weak and"low quality."In the case of nanosized metal objects,however,this atomic-level mess has the opposite effect:these parts can be three-to-five-times stronger than similarly sized structures with more orderly atomic arrangements.The work was conducted in the lab of Julia R.Greer,the Ruben F.and Donna Mettler Professor of Materials Science,Mechanics and Medical Engineering;and Fletcher Jones Foundation Director of the Kavli Nanoscience Institute.It is described in apaper appearing in the journal Nano Letters.The new technique is similar to another announced by the team last year,but with each step of the process reimagined to work at the nanoscale.However,this presents an additional challenge:the manufactured objects are not visible to the naked eye or easily manipulatable.The process starts with preparing aphotosensitive"cocktail"that is largely comprised of ahydrogel,a kind of polymer that can absorb many times its own weight in water.This cocktail is then selectively hardened with alaser to build a3-D scaffold in the same shape as the desired metal objects.In this research,those objects were aseries of tiny pillars and nanolattices.The hydrogel parts are then infused with an aqueous solution containing nickel ions.Once the parts are saturated with metal ions,they are baked until all the hydrogel is burned out,leaving parts in the same shape as the original,though shrunken,and consisting entirely of metal ions that are now oxidized(bound to oxygen atoms).In the final step,the oxygen atoms are chemically stripped out of the parts,converting the metal oxide back into ametallic form.In the last step,the parts develop their unexpected strength."There are all these thermal and kinetic processes occurring simultaneously during this process,and they lead to avery,very messy microstructure,"she says."You see defects like pores and irregularities in the atomic structure,which are typically considered to be strength-deteriorating defects.If you were to build something out of steel,say,an engine block,you would not want to see this type of microstructure because it would significantly weaken the material."However,Greer says they found exactly the opposite.The many defects that would weaken ametal part at alarger scale strengthen the nanoscale parts instead.When apillar is defect free,failure occurs catastrophically along what is known as agrain boundary—the place where the microscopic crystals that make up material butt up against each other.But when the material is full of defects,a failure cannot easily propagate from one grain boundary to the next.That means the material won‘t suddenly fail because the deformation becomes distributed more evenly throughout the material. 查看详细>>

A new technology being pioneered at Caltech is allowing researchers to"evolve"optical devices and then print them out using aspecialized type of 3D printer.These devices are made of so-called optical metamaterials that derive their properties from structures so small they are measured in nanometers,and they may allow cameras and sensors to detect and manipulate properties of light in ways not previously possible at small scales.The work was conducted in the lab of Andrei Faraon,the William L.Valentine Professor of Applied Physics and Electrical Engineering and appears in the journal Nature Communications.This isn‘t the first time Faraon has developed optical metamaterials,but he says it is the first time these materials have been pushed into three dimensions."Generally,most of these things are done in athin layer of material.You take avery thin piece of silicon or some other material and you process that to get your device,"he says."However,[the field of]optics lives in athree-dimensional space.What we are trying to investigate here is what is possible if we make three-dimensional structures smaller than the wavelength of light that we are trying to control."As ademonstration of the new design technique,Faraon‘s lab has created tiny devices that can sort incoming light,in this case infrared,by both wavelength and polarization,a property that describes the direction in which the light waves vibrate.Though devices that can separate light in this way already exist,the devices made in Faraon‘s lab could be made to work with visible light and small enough that they could be placed directly over the sensor of acamera and direct red light to one pixel,green light to another,and blue light to athird.The same could be done for polarized light,creating acamera that can detect the orientation of surfaces,a useful ability for the creation of augmented and virtual reality spaces.A glance at these devices reveals something rather unexpected.Whereas most optical devices are smooth and highly polished like alens or prism,the devices developed by Faraon‘s lab look organic and chaotic,more like the inside of atermite mound than something you would see in an optics lab.This is because the devices are evolved by an algorithm that continually tweaks their design until they perform in the desired way,similar to how breeding might create adog that is good at herding sheep,says Gregory Roberts,graduate student in applied physics and lead author of the paper."The design software at its core is an iterative process,"Roberts says."It has achoice at every step in the optimization for how to modify the device.After it makes one small change,it figures out how to make another small change,and,by the end,we end up with this funky-looking structure that has ahigh performance in the target function that we set out in the beginning."Faraon adds:"We actually do not have arational understanding of these designs,in the sense that these are designs that are produced via an optimization algorithm.So,you get these shapes that perform acertain function.For example,if you want to focus light to apoint—so basically what alens does—and you run our simulation for that function,you most likely will get something that looks very similar to alens.However,the functions that we are targeting—splitting wavelengths in acertain pattern—are quite complicated.That‘s why the shapes that come out are not quite intuitive."To turn these designs from amodel on acomputer into physical devices,the researchers made use of atype of 3D printing known as two-photon polymerization(TPP)lithography,which selectively hardens aliquid resin with alaser.It‘s not unlike some of the 3D printers used by hobbyists,except it hardens resin with greater precision,allowing structures with features smaller than amicron to be built.Faraon says that the work is aproof of concept but that with abit more research,it could be made with apractical manufacturing technique.The paper describing the work,"3D-patterned inverse-designed mid-infrared metaoptics,"appears in the April 14 issue of Nature Communications.Additional co-authors are Conner Ballew,formerly of Caltech and now with JPL,which Caltech manages for NASA;Tianzhe Zheng,graduate student in applied physics;Sarah Camayd-Muñoz,formerly of Caltech and now with Johns Hopkins University;and Juan C.Garcia and Philip W.C.Hon of Northrop Grumman.Funding for the research was provided by the Defense Advanced Research Projects Agency(DARPA),the Rothenberg Innovation Initiative,the Clinard Innovation Fund at Caltech,and the Army Research Office. 查看详细>>

Most of the time,when someone gets acut,scrape,burn,or other wound,the body takes care of itself and heals on its own.But this is not always the case.Diabetes can interfere with the healing process and create wounds that will not go away and that could become infected and fester.These kinds of chronic wounds are not just debilitating for the people suffering from them.They are also adrain on healthcare systems,representing a$25 billion financial burden in the United States alone each year.A new kind of smart bandage developed at Caltech may make treatment of these wounds easier,more effective,and less expensive.These smart bandages were developed in the lab of Wei Gao,assistant professor of medical engineering,Heritage Medical Research Institute Investigator,and Ronald and JoAnne Willens Scholar."There are many different types of chronic wounds,especially in diabetic ulcers and burns that last along time and cause huge issues for the patient,"Gao says."There is ademand for technology that can facilitate recovery."Unlike atypical bandage,which might only consist of layers of absorbent material,the smart bandages are made from aflexible and stretchy polymer containing embedded electronics and medication.The electronics allow the sensor to monitor for molecules like uric acid or lactate and conditions like pH level or temperature in the wound that may be indicative of inflammation or bacterial infection.The bandage can respond in one of three ways:First,it can transmit the gathered data from the wound wirelessly to anearby computer,tablet,or smartphone for review by the patient or amedical professional.Second,it can deliver an antibiotic or other medication stored within the bandage directly to the wound site to treat the inflammation and infection.Third,it can apply alow-level electrical field to the wound to stimulate tissue growth resulting in faster healing.In animal models under laboratory conditions,the smart bandages showed the ability to provide real-time updates about wound conditions and the animals‘metabolic states to researchers,as well as offer speed healing of chronic infected wounds similar to those found in humans.Gao says the results are promising and adds that future research in collaboration with the Keck School of Medicine of USC will focus on improving the bandage technology and testing it on human patients,whose therapeutic needs may be different than those of lab animals."We have showed this proof of concept in small animal models,but down the road,we would like to increase the stability of the device but also to test it on larger chronic wounds because the wound parameters and microenvironment may vary from site to site,"he says.The paper describing the research,"A stretchable wireless wearable bioelectronic system for multiplexed monitoring and combination treatment of infected chronic wounds,"appears in the March 24 issue of the journal Science Advances.Co-authors are postdoctoral scholar research associates in medical engineering Ehsan Shirzaei Sani and Yu Song;medical engineering graduate students Changhao Xu(MS‘20),Canran Wang,Jihong Min(MS‘19),Jiaobing Tu(MS‘20),Samuel A.Solomon,and Jiahong Li;and Jaminelli L.Banks and David G.Armstrong of the Keck School of Medicine of USC.Funding for the research was provided by the National Institutes of Health,the National Science Foundation,the Office of Naval Research,the Heritage Medical Research Institute,the Donna and Benjamin M.Rosen Bioengineering Center at Caltech,the Rothenberg Innovation Initiative at Caltech,and aSloan Research Fellowship. 查看详细>>

As with many of Caltech‘s time-honored traditions,the annual ME72 Engineering Design Competition pushes students to the limits of possibility.Unlike other Caltech traditions,ME72 involves ball-launching,self-driving,all-terrain robots—which occasionally burst into flames.Every year from September to March,third-year mechanical engineering undergraduates take ME 72,a two-term,hands-on lab course.Advised by instructor Michael Mello(PhD‘12),teaching professor of mechanical and civil engineering,student teams each design and build three robots to participate in aunique competition created by that year‘s teaching assistants(TAs).This year,the"Rubble Rush:Rabblerousing Racquetball Rustlers"competition on March 9challenged five teams of five to seven students to build one mobile robot to collect racquetballs from adispenser,one stationary robot to shoot those balls into goals,and another mobile robot to traverse an obstacle course.Points were awarded for successful goals,and balls worth extra points went to teams whose robots navigated the obstacle course autonomously,without the need for remote control.A round-robin tournament pitted each team‘s robots against one another in four-minute matches,and teams that scored the most points advanced to afinal bracket playoff."I‘ve been surprised by the variety of robots we‘re seeing this year,"said TA Martin Peticco at this year‘s competition.Peticco‘s team won the competition last year."One team is trying to use computer vision to navigate the obstacle course autonomously,and another team is using ultrasonic signals,which work kind of like echolocation."Students gain the necessary technical knowledge in prior mechanical engineering courses at Caltech."ME14 was agood starting ground to learn the basics of the engineering process,"says Jonah Rolfness,from team Purple Prickly Pineapples."ME72 is kind of like abeefed-up version of that."Students begin the class designing their robots in computer-aided design(CAD)software.Then they build prototypes,test,fail,go back to the drawing board,and build again."Every team goes through the forming,storming,norming,and performing stages of group dynamics,"Mello says.Assisted by co-instructor Paul Stovall,lecturer in mechanical engineering and supervisor of the mechanical engineering shop;and Trent Wilson,lab machining assistant;students spend many hours constructing their robots."We advise them on how to manufacture parts,troubleshoot,and fix things that are broken,"Stovall says."Most students spend at least six hours aday in the shop."This time commitment is no easy feat.When asked how long it took to build their three bots,one member from team Candace said it felt like"100 million hours."Though ME72 is known to take over third-year mechanical engineering students‘lives,they come away with invaluable skills."I had an internship last year at OffWorld,a company that builds smart robots for space and mining applications,"says TA Logan Hayes,a fourth-year undergraduate who took the class last year."ME72 was very helpful in preparing me for that and getting experience in the full design process."All the students‘labor came to fruition on March 9.Cheered on by acrowd of Caltech peers and around 40 visiting students from Sierra Madre Middle School,teams faced off on the grassy battlefield of Beckman Mall.Mello and competition announcer Gunnar Ristroph(BS‘06)narrated the play-by-play for the audience.In an energetic start to the day,team MechE Wednesdays faced off against team[REDACTED].MechE Wednesdays employed the unique strategy of parking their shooting robot under the racquetball dispenser,allowing it to collect balls with an extended arm and volley off goal shots immediately.[REDACTED]‘s robots were among the most reliable of the bunch but couldn‘t manage to outscore MechE Wednesdays.In the second match,team Squeezable and Bouncy started off with astrong lead against Purple Prickly Pineapples.But in the middle of play,one of Squeezable and Bouncy‘s robots caught fire and an acrid smell filled the air.A TA swooped in and removed the bot‘s battery to around of applause from the audience.Eighth-grader Angelica Melchor and her classmates enjoyed the action from front-row bleacher seats next to the course."It‘s super cool to see what Caltech students can build,"Melchor said."I‘m on the robotics team at school,and I‘d love to go to Caltech someday and do this competition." 查看详细>>

Leandra Davis,an established professional in higher education capital and master planning,has been named the new executive director for the Office of Planning,Design,and Construction within Caltech Facilities.She will begin her tenure at the Institute on April 10.Davis joins Caltech after spending more than 15 years at the University of Pennsylvania,where she most recently led the planning,design,and construction group in the School of Engineering,managing ateam of eight project management professionals who oversee interior renovation and new construction projects.In her time at Penn,Davis led master planning and strategic planning initiatives,five-year capital budgeting,and new construction projects as well as advising senior leadership on space allocation and collaborating on sustainability initiatives across the university.Davis will be responsible for the overall leadership,direction,and coordination of the Facilities staff members who provide planning,design,engineering,and construction services to Caltech."We are thrilled to have Leandra join our Facilities team,"said David Kang,associate vice president of facilities."She brings awealth of knowledge and experience in planning and managing complex labs and facilities.That,coupled with Leandra‘s superb background in sustainability and effective communication,will make her atrue asset to the Institute."Davis received three Penn Models of Excellence Awards and is atrustee on the Board of the Corinthian Yacht Club(CYC)of Philadelphia,where she leads the CYC House and Grounds Committee‘s master planning,and founded the CYC‘s Diversity,Equity,and Inclusion Committee.Davis has aBS from Drexel University in interior design,an executive certificate in business essentials from Wharton,is aLEED-accredited professional,and has an MS in organizational dynamics from the University of Pennsylvania."I am energized by the opportunity to collaborate with the Caltech community to build and renovate the Institute‘s cutting-edge research and education facilities,"Davis says."I look forward to supporting Caltech‘s research mission and building trust and transparency with the division staff and faculty.I believe in bringing the brightest minds together to ideate and problem solve,and am thrilled to have the opportunity to partner with the Facilities team as well as with faculty and staff to plan for and build best-in-class research and education facilities." 查看详细>>

Photoacoustic microscopy(PAM)is arelatively new imaging technique that uses laser light to induce ultrasonic vibrations in tissue.These ultrasonic vibrations,along with acomputer that processes them,can then be used to create an image of the structures of the tissue in much the same way ultrasound imaging works.In the last few years,Lihong Wang,Caltech‘s Bren Professor of Medical Engineering and Electrical Engineering,has developed PAM technologies that can image changing blood flow in the brain,detect cancerous tissue,and even identify individual cancer cells.However,one limitation of high-resolution(i.e.,optical-resolution)PAM has been its narrow depth of field,meaning that it can only focus on athin layer(approximately 30 micrometers,or about the length of one skin cell,with one to two micrometers of resolution)of tissue at atime.To see something above or below the plane that the device is viewing,it needs to refocus above or below that plane.For comparison,imagine aperson putting on reading glasses to do acrossword puzzle.In anew paper in the journal Nature Photonics,Wang and his research team show how they developed anew variant of PAM called needle-shaped beam photoacoustic microscopy,or NB-PAM,which that has adepth of field nearly 14 times greater than what was achievable before.This means NB-PAM can create 3-D imagery of samples without refocusing and better image samples with uneven surfaces."Some applications,such as studying tissue samples without needing to use amicroscope slide,require imaging of uneven surfaces at high spatial resolution,"says Rui Cao,lead author and postdoctoral scholar research associate in medical engineering."Conventional PAM grapples with the trade-off between resolution and depth of field,which has been overcome by our new technology."NB-PAM improves its depth of field over its related PAM technologies by using abeam of laser light that is longer and thinner,hence"needle shaped."This change in the optical characteristics of the beam avoids some of the drawbacks associated with other attempts to increase the depth of field of PAM technology,such as working more slowly,or requiring more computer processing power.This needle-shaped beam is created using aspecialized item known as adiffractive optical element(DOE).To the casual observer,a DOE looks like atiny sheet of glass,but it is actually apiece of fused silica with precise patterns engraved on its surface.Those patterns reshape the beam of light that is used for imaging,so that it no longer focuses to asharp point along the propagation axis but is instead drawn out into along thin neck.Consequently,it is able to clearly image objects over agreater range of depths.That greater depth of field was demonstrated by the researchers in two ways:imaging fresh organ samples using an ultraviolet laser and imaging in vivo mouse brain vasculature using ablue laser."This technology provides new opportunities for studying tissue samples during surgery,which would allow complete removal of cancer cells and maximal preservation of normal ones,"says Wang,who is also the Andrew and Peggy Cherng Medical Engineering Leadership Chair;Executive Officer for Medical Engineering."Translation into the operating room is anatural future avenue of research."The paper describing NB-PAM,titled"Optical-resolution photoacoustic microscopy with aneedle-shaped beam,"appears in the December 1issue of Nature Photonics.Co-authors are Lei Li(PhD‘19),Yide Zhang,and Samuel Davis,all postdoctoral scholar research associates in medical engineering;medical engineering graduate student Yilin Luo;Jingjing Zhao and Adam de la Zerda of Stanford University;Lin Du of University of Pennsylvania;and Qifa Zhou and Laiming Jiang of USC.Funding for the research was provided by the National Institutes of Health. 查看详细>>

Alzheimer‘s disease is aneurodegenerative condition that damages aperson‘s ability to think,remember,and perform basic functions.According to the National Institutes of Health,Alzheimer‘s affects more than 6million Americans,mostly ages 65 and older.Though the neurological damage from the disease is irreversible,early detection and intervention has been shown to slow its progression.Before the onset of Alzheimer‘s physical symptoms,the most commonly used method to measure an individual‘s risk of developing the disease is through measuring levels of certain proteins,such as amyloid beta and tau proteins,in spinal fluid.This test is invasive,painful,and expensive.Now,a team from Caltech and the Huntington Medical Research Institutes,have made progress toward developing asimple behavioral test to measure an individual‘s risk of developing Alzheimer‘s before any symptoms arise.The research was conducted in the laboratory of Shinsuke Shimojo,Gertrude Baltimore Professor of Experimental Psychology.A paper describing the findings appears in the journal Alzheimer‘s&Dementia on September 20.Shimojo is an affiliated faculty member with the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech."Early detection of Alzheimer‘s disease is important in order to take interventions that can slow the progression of the disease,"says the study‘s first author Shao-Min Sean Hung,formerly apostdoctoral scholar in the Shimojo laboratory and now an assistant professor at Waseda University in Japan."Before the onset of the disease,by definition,cognitively healthy people do not have behavioral symptoms—and thus it‘s not possible to do traditional behavioral assessments for the disease because there are no behavioral symptoms yet.What we‘re trying to do is develop atest to detect behavioral abnormalities long before any onset of symptoms and in aless invasive way than measuring spinal fluid."The study involved 40 people with an average age of 75 and all cognitively healthy,who underwent myriad tests related to Alzheimer‘s risk:magnetic resonance imaging(MRI)of the brain,genome sequencing,and the aforementioned invasive spinal fluid measurements.From these biological markers,individuals could be categorized as high risk or low risk.The researchers aimed to develop abehavioral test whose results would correlate with these biological measurements.The team developed atask in which aparticipant undergoes aso-called Stroop Paradigm test.In this common test,a person is shown aword—the name of acolor—displayed in colored ink.However,the word itself does not necessarily match the color of the printed word—for example,the word"RED"is printed in the color green.In each iteration of the task,the participant is asked to name either the color of the word or the word itself.Compared to naming the word itself,naming the color of the text is considered"high effort"—it is more challenging than it might seem.In this study,the researchers also added ahidden element to the Stroop Paradigm.Right before the actual target is shown,a colorless word is flashed rapidly on the screen—so rapidly that aparticipant cannot detect it consciously.The colorless word is intended to unconsciously distract the participant and measure"implicit cognition."In addition to conscious and intentional information gathering or"explicit cognition,"our brains have aseparate system in which sensory information is digested without conscious awareness—this is known as implicit cognition. 查看详细>>

A new type of vaccine provides protection against avariety of SARS-like betacoronaviruses,including SARS-CoV-2 variants,in mice and monkeys,according to astudy led by researchers in the laboratory of Caltech‘s Pamela Bjorkman,the David Baltimore Professor of Biology and Bioengineering.Betacoronaviruses,including those that caused the SARS,MERS,and COVID-19 pandemics,are asubset of coronaviruses that infect humans and animals.The vaccine works by presenting the immune system with pieces of the spike proteins from SARS-CoV-2 and seven other SARS-like betacoronaviruses,attached to aprotein nanoparticle structure,to induce the production of abroad spectrum of cross-reactive antibodies.Notably,when vaccinated with this so-called mosaic nanoparticle,animal models were protected from an additional coronavirus,SARS-CoV,that was not one of the eight represented on the nanoparticle vaccine."Animals vaccinated with the mosaic-8 nanoparticles elicited antibodies that recognized virtually every SARS-like betacoronavirus strain we evaluated,"says Caltech postdoctoral scholar Alexander Cohen(PhD‘21),co-first author on the new study."Some of these viruses could be related to the strain that causes the next SARS-like betacoronavirus outbreak,so what we really want would be something that targets this entre group of viruses.We believe we have that."The research appears in apaper in the journal Science on July 5."SARS-CoV-2 has proven itself capable of making new variants that could prolong the global COVID-19 pandemic,"says Bjorkman,who is also aMerkin Institute Professor and executive officer for Biology and Biological Engineering."In addition,the fact that three betacoronaviruses—SARS-CoV,MERS-CoV,and SARS-CoV-2—have spilled over into humans from animal hosts in the last 20 years illustrates the need for making broadly protective vaccines."Such broad protection is needed,Bjorkman says,"because we can‘t predict which virus or viruses among the vast numbers in animals will evolve in the future to infect humans to cause another epidemic or pandemic.What we‘re trying to do is make an all-in-one vaccine protective against SARS-like betacoronaviruses regardless of which animal viruses might evolve to allow human infection and spread.This sort of vaccine would also protect against current and future SARS-CoV-2 variants without the need for updating."How it works:A vaccine composed of spike domains from eight different SARS-like coronaviruses The vaccine technology to attach pieces of avirus to protein nanoparticles was developed initially by collaborators at the University of Oxford.The basis of the technology is atiny cage-like structure(a"nanoparticle")made up of proteins engineered to have"sticky"appendages on its surface,upon which researchers can attach tagged viral proteins.These nanoparticles can be prepared to display pieces of one virus only("homotypic"nanoparticles)or pieces of several different viruses("mosaic"nanoparticles).When injected into an animal,the nanoparticle vaccine presents these viral fragments to the immune system.This induces the production of antibodies,immune system proteins that recognize and fight off specific pathogens,as well as cellular immune responses involving Tlymphocytes and innate immune cells.In this study,the researchers chose eight different SARS-like betacoronaviruses—including SARS-CoV-2,the virus that has caused the COVID-19 pandemic,along with seven related animal viruses that could have potential to start apandemic in humans—and attached fragments from those eight viruses onto the nanoparticle scaffold.The team chose specific fragments of the viral structures,called receptor-binding domains(RBDs),that are critical for coronaviruses to enter human cells.In fact,human antibodies that neutralize coronaviruses primarily target the virus‘s RBDs.The idea is that such avaccine could induce the body to produce antibodies that broadly recognize SARS-like betacoronaviruses to fight off variants in addition to those presented on the nanoparticle by targeting common characteristics of viral RBDs.This design comes from the idea that the diversity and physical arrangement of RBDs on the nanoparticle will focus the immune response toward parts of the RBD that are shared by the entire SARS family of coronaviruses,thus achieving immunity to all.The data reported in Science today demonstrates the potential efficacy of this approach. 查看详细>>

Building amap of the complex human brain and its approximately 100 billion individual neurons is no easy task.As aprecursor to tackling that monumental challenge,researchers have started off with something smaller and easier—the mouse brain—in order to understand different cell types and how they are connected,and also to perfect the technological approaches to do so.Now,a new paper describes the minute genomic details of the mouse brain at unprecedented resolution and how several types of genomics techniques were combined to enable this analysis,which was led by graduate student A.Sina Booeshaghi(MS‘19).The study was primarily conducted in the laboratory of Lior Pachter(BS‘94),Bren Professor of Computational Biology and Computing and Mathematical Sciences,and is part of acollaboration called the Brain Research through Advancing Innovative Neurotechnologies(BRAIN)Initiative–Cell Census Network(BICCN),funded by the National Institutes of Health.This study and several other papers from the BICCN collaboration appear in the journal Nature on October 6.In this new group of papers,13 teams focused on the mouse primary motor cortex,the region of the mouse brain that controls movement.Booeshaghi‘s team analyzed genomic data from brain cells collected by collaborators at the Allen Institute,a nonprofit bioscience research organization based in Seattle,Washington.By combining three different experimental techniques,each with their own strengths and weaknesses,the team was able to make detailed characterizations of gene expression in mouse cortex brain cells.The combination of techniques,Pachter says,leverages the strength of individual techniques in away that achieves more than the sum of their parts.The study achieved agranular level of detail by looking at what are known as gene isoforms.To understand isoforms,it is necessary to understand the expression of individual RNA transcripts that comprise genes;gene expression is the process by which the DNA of agene is transcribed into RNA,and then RNA is read by molecular machinery to create proteins.In higher eukaryotes like humans,this flow of information includes aprocess called splicing,in which RNA gets chopped up and some of the pieces are glued back together before being turned into aprotein.This cut-and-paste process produces many"flavors"of transcripts of the same gene:isoforms.The isoforms can translate into proteins with different functions.By examining such isoforms,Booeshaghi and his collaborators determined that the variants are acrucial aspect contributing to functional differences between brain cells.An examination of isoforms is particularly important in the brain;the splicing process is highly active in brain tissue,and many neurological diseases result from disruptions to splicing.The paper is titled"Isoform cell type specificity in the mouse primary motor cortex."In addition to Booeshaghi and Pachter,additional co-authors are Zizhen Yao,Cindy van Velthoven,Kimberly Smith,Bosiljka Tasic,and Hongkui Zeng of the Allen Institute for Brain Science.Funding was provided by the National Institutes of Health Brain Initiative.Lior Pachter is an affiliated faculty member with the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech. 查看详细>>