Podcast appearances and mentions of sophia chen

In this podcast episode, MRS Bulletin's Sophia Chen interviews Lane Martin from Rice University about characterization of relaxor ferroelectrics, materials with noteworthy energy-conversion properties used in sensors and actuators. Martin's research team investigated the material's behavior at the nanoscale. The researchers found that the specific thin film they studied—the alloy lead magnesium niobate lead titanate—exhibited excellent properties down to 25–30 nm thick before they would start to shift. This work was published in a recent issue of Nature Nanotechnology.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Beth Dickey from Carnegie Mellon University about her new approach to inducing ferroelectricity into a material. Dickey's research group worked with a class of materials known as wurtzites. The researchers specifically studied aluminum nitride and zinc oxide, which are not ferroelectric in their pristine form at room temperature. However, alloys of these materials are ferroelectric. When the researchers stacked the ferroelectric alloy with a non-ferroelectric wurtzite and applied electric fields to the material, they found that the crystal lattice of the ferroelectric layer began to invert, then switching propagated into the pristine wurtzite, confirming that the entire material was ferroelectric. The results of this study could lead to development of ferroelectric materials for computers where memory and computation can be brought together into a single device, saving energy. This work was published in a recent issue of Nature. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Xingchen Ye of Indiana University about his research group's studies on the fundamental behavior of colloidal materials. Colloidal materials consist of liquids with nanoparticles suspended in them. Ye's team is interested in how a colloidal material's properties change as the team spatially rearranges the nanoparticles in the liquid. They looked specifically at the self-assembly of gold nanocubes into a lattice structure. Ye's team studied how that structure gives rise to the material's bulk properties. This work was published in a recent issue of Nature Chemical Engineering.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Bowen Deng, a graduate student in Gerbrand Ceder's group at the University of California, Berkeley, about their work on increasing the accuracy of artificial intelligence/machine learning materials prediction models. The use of computer simulations to predict the interaction between atoms in a given molecule is being replaced by machine learning. Researchers describe the atoms' collective interactions as a quantity of energy, where higher energies correspond to stronger forces holding the molecule together. Now, Deng's research group studied three machine learning models and found that they tend to predict lower energies than what is accurate by about 20 percent. The researchers have determined that these underpredictions were caused by biased training data and they found a way to remedy the situation. This work was published in a recent issue of NPJ Computational Materials.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Gwangmin Bae of Korea University about his work with colleagues on the design of a new smart window system that utilizes compression. Like other smart windows, this window makes use of pores within the material to adjust its transparency. However, instead of using a stretchy material that controls light scattering through the pores, Bae and colleagues used a material that compresses in thickness. That is, the window becomes more transparent when it is compressed. The researchers place this structured porous material made of the polymer polydimethylsiloxane or PDMS between two panes of glass to create the smart window. This work was published in a recent issue of Nature Communications.

In this podcast episode, MRS Bulletin's Sophia Chen interviews postdoctoral research fellow Rohit Pratyush Behera and Prof. Hortense Le Ferrand of Nanyang Technological University in Singapore about their design of a strong and tough ceramic that absorbs energy, inspired from biology. They borrowed microscopic designs found in a mollusk, a mantis shrimp, and the enamel casing surrounding human teeth. The researchers stacked round discs of aluminum oxide particles in horizontal layers in a helical structure, then encased the structure in an extra protective layer made of alumina nanoparticles. The aluminum oxide in the discs is designed to respond to an external magnetic field, modifying the orientation of the discs layer by layer, consequently adjusting the properties of the ceramic composites. This work was published in a recent issue of Cell Reports Physical Science.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Yen-Hung Lin of Hong Kong University of Science and Technology about his work to eliminate defects in perovskite solar cells. Lin's group treated the perovskites with a category of molecules known as amino-silanes, which bind vacancies in the perovskites, preventing recombination of the electrons and holes. The amino-silane treatment retained the device's performance at 95% power conversion efficiency for more than 1500 hours. This work was published in a recent issue of Science. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Michael Dickey of North Carolina State University about the discovery and mechanical properties of glassy gels. Dicky credits his postdoc Meixiang Wang who, while studying ionic liquids, created the first glassy gel. Dicky's group found that the mechanical properties of their glassy gel include shape memory, self-healing, and adhesion. While other materials may demonstrate comparable toughness and stretchiness, the glassy gel offers an advantage because of its simple curing process. This work was published in a recent issue of Nature. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Mihir Pendharkar of Stanford University about characterizing electronic properties of twistronics materials. Twistronics refers to a type of electronic device consisting of two-dimensional materials layered at a relative twist angle, forming a new periodic structure known as moiré superlattices. Pendharkar and colleagues studied different configurations of graphene layered with hexagonal boron nitride. Determining the twist angle of any particular sample is extremely time-consuming. By developing a characterization technique called torsional force microscopy, Pendharkar and colleagues have reduced the time to a matter of hours. This work was published in a recent issue of Proceedings of the National Academy of Sciences. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Irmgard Bischofberger of the Massachusetts Institute of Technology about her investigation of how chirality emerges in nature. She uses liquid crystal molecules of disodium chromoglycate in her studies. When the molecules are dissolved in water, they form linear rods. The research group then forces the rods through a microfluidic cell, causing the rods to assemble into spiral structures without mirror symmetry. The achiral structure transformed into a chiral one. What is unique, says Bischofberger, is that the new material is composed of non-chiral building blocks. This work was published in a recent issue of Nature Communications. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Kaveh Ahadi from The Ohio State University about a material his group developed that maintains superconductivity in a magnetic field. The researchers grew a film of lanthanum manganite on a crystal of potassium tantalate. When lowered to the temperature of 2 Kelvin, the material is a superconductor. When Ahadi's group applied 25 Teslas of magnetic field, the material stayed superconducting. Even though the material is not of practical use, Ahadi says that studying this material will help researchers better understand the mechanisms that lead to superconductivity. This work was published in Nano Letters. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Nathan Gabor from the University of California, Riverside about his group's work on imaging and directing the flow of electrons in electronic devices. They designed their device by taking a crystal of yttrium iron garnet, which does not conduct electricity, and putting a nanometers-thick layer of platinum, which does conduct electricity, on top of it. When they illuminate the device with a laser, this device produces an electric current. They further discovered that when they combine the crystal with the platinum, the interface between the two materials exhibits magnetic properties. Gabor's research team used this sensitivity to a magnetic field to steer the electron flow in the device. This work was published in Proceedings of the National Academy of Sciences.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Surabhi Madhvapathy of Northwestern University about an implantable bioelectronics system that can perform early detection of kidney transplant rejection in rats. Madhvapathy and her colleagues have developed a wireless sensor that attaches to the kidney itself. The biosensor measures the organ's temperature and its thermal conductivity. These can point toward inflammation in the kidney, which can be a sign of organ rejection. This work was published in a recent issue of Science.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Alice Soragni of the University of California, Los Angeles about her work in precision oncology. Rather than sequence the DNA of a patient's tumor, Soragni uses bioprinting to create organoids from the patient's cells. She then adds various drugs to the cells to directly test their response to each drug. To check the effectiveness of the drugs, Soragni's group measures the organoid's mass with a technique called interferometry. Interferometry is a non-invasive technique that involves shining light on the cells to monitor their response to the drug. This process allows Soragni to characterize the organoid's response to the drug in fine detail. This work was published in a recent issue of Nature Communications. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Xuchen Wang of Karlsruhe Institute of Technology in Germany about his work on photonic time crystals. While conventional crystals are composed of repeating unit cells in space, such as eight carbon atoms arranged in a cube to form a diamond, a photonic time crystal has a structure that repeats in time. Theoretical predictions of photonic time crystals referred to designs consisting of three-dimensional metamaterials whose properties are difficult to manipulate in the laboratory. Wang and his collaborators have adapted the three-dimensional time crystal design to a two-dimensional metasurface. They arranged copper structures on the surface, using conventional printed circuit board technology. The structures look like a forest of mushrooms where the researchers placed a variable capacitor, known as a varactor, between each mushroom. To create the device, the researchers apply changing external voltages to the varactor, modulating the material's electromagnetic properties in time. Wang then confirmed experimentally that this device amplified microwave signals that he sent across its surface. This work was published in a recent issue of Science Advances. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Widi Moestopo, a former graduate student in Julia Greer's laboratory at the California Institute of Technology (Caltech) and now a postdoc at Lawrence Livermore National Laboratory about their work incorporating microknots in architected materials. Using two-photon lithography, Moestopo scans a resin with a laser to create and shape a three-dimensional (3D) object within foam. Moestopo then used a solvent to wash away the remaining, unconverted resin. In this way, he sculpted the knots out of the resin, rather than tying the knots like shoelaces. This 3D structure is formed from a lattice of 3D rhombuses, where each side of the rhombus consists of three strands of fiber. These fibers are woven around each other to form knots. The result is a materials with high deformability and tensile toughness. This work was published in a recent issue of Science Advances. 

Today on Boston Public Radio: The world is watching Tennessee after 2 young black democratic lawmakers were expelled for speaking out of turn at a gun safety protest. Tennessee republicans didn't expel the 3rd white democratic lawmaker who was participated in the same protest. We opened the lines for listeners to weigh in. Boston Globe's Shirley Leung will talk about the state's clawback of unemployment benefits after a 3 year pause, the state gambling commission rejecting bets on the marathon, and more. Nancy Gertner is back via Zoom, we'll talk with her about Clarence Thomas privately accepting (very) expensive gifts from one GOP donor. She'll also talk about the Trump charges, and what the Wisconsin Supreme Court vote mean for Democrats in post-Dobbs America. J. Ivy is a Grammy-winning poet and the man who gave John Legend his name. He's performing at the Boston City Winery, he'll join via Zoom. Sue O'Connell will discuss Marty Walsh siding with the NFL in a dispute over players wearing pride jerseys, plus the Twitter labelling NPR's account as 'state-affiliated media' (which is untrue), the latest pro-gun legislation out of Florida and more. Sophia Chen, Jane Park & Felice Ling are all a part of a late-night event “Asian Glow” at the Pao Arts Center in Chinatown. It's all about creating space for Asian creatives & performers, we'll hear some music from singer/songwriter Jane Park and magic from Felice Ling. We wrapped up the show America's favorite Easter-time debate: peeps. We asked listeners for their thoughts while a producer attempted to buy some peeps but they were sold out in various stores.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Prof. Esma Ismailova and graduate student Marina Galliani from Mines Saint-Etienne about their work toward creating biocompatible, eco-friendly materials for wearable electronics. For this particular project, they developed a conducting material based on a commercial polymer known as PEDOT-PSS, in a water-based solution. They combined it with various solvents to tune the electrical conductivity, which is dependent on the shape and structure of the polymers in the material as they dry. The researchers tested the material's conductivity on several substrates, including paper-based substrates and textiles. To make the material printable, they also needed to tune the material's viscosity. Because the material relies on inkjet printers that are already commonly available, this material is relatively easy to incorporate into industrial processes. This work was published in a recent issue of APL Bioengineering. 

❤️健康長壽是每個人的心願，但每個人都會變老，您有思考過年老之後生活會面臨那些選擇嗎？ 如果家中有長輩需要照護機構或養老院的照料，那我們該如何幫助他們選擇適合的養老院呢？ 本集將與聽眾朋友們分享美國各種不同的老年生活方式，以及如何根據自己或家人的需求做出合適的選擇。 受訪者：Sophia Chen 主持人：姜至真

In this podcast episode, MRS Bulletin's Sophia Chen interviews Jiahui Li, a graduate student at the University of Illinois Urbana-Champaign about designing structures out of gold nanoparticles. When the nanoparticle structure takes the shape of a pinwheel, different types of light interact with the structure differently due to its chirality. Different wavelengths might be transmitted depending on whether the light's polarization is rotating clockwise or counterclockwise, which could make this structure useful for filtering light in optical applications. This work was published in a recent issue of Nature (https://doi.org/10.1038/s41586-022-05384-8).

In this podcast episode, MRS Bulletin's Sophia Chen interviews Murat Onen, a postdoctoral researcher at the Massachusetts Institute of Technology, about analog deep learning that could help lower the cost of training artificial intelligence (AI). The programmable analog device stores information in the same place where the information is processed. The resistor's main material is tungsten oxide, which can be reversibly doped with protons from an electrolyte material known as phosphosilicate glass, or PSG, layered on top of the tungsten oxide. Palladium is above the PSG layer, which is a reservoir for the protons when they are shuttled out of the tungsten oxide to make it more resistive. “When protons get in, it becomes more conductive. When the protons go out, it becomes less conductive,” says Onen. The resistance of this device responds in about 5 ns. This work was published in a recent issue of Science (doi:10.1126/science.abp8064).

On this episode of Knowing Animals, we speak with Professor Chris Hopwood, Professor of Personality Psychology at the University of Zurich. He is a co-founder of the PHAIR Society (The Society for the Psychology of Human-Animal Intergroup Relations), and the editor of the society's journal, PHAIR. We discuss Chris's work on the links between personality and diet, including his paper 'Development and validation of the Motivations to Eat Meat Inventory', published open access in the journal Appetite, which was coauthored with Jared Piazza, Sophia Chen, and Wiebke Bleidorn.

In this podcast episode, MRS Bulletin's Sophia Chen interviews Bin Ouyang of Florida State University about making a better cathode for lithium ion batteries. The current use of cobalt and nickel in their cathodes causes Li-ion batteries to contract in volume and degrade. Ouyang and his colleagues simulated and then fabricated new cathode materials that do not use cobalt or nickel and also degrade less after being charged and discharged. To achieve this, they found that they needed to design a material with disorder in its crystal structure. They found that replacing cobalt and nickel with vanadium and niobium leads to a battery with a small change of volume. The results provide a model for the further search of viable cathode materials to design lithium-ion batteries that are entirely made of solids. This study is published in Joules (doi:10.1016/j.joule.2022.05.018). 

In this podcast episode, MRS Bulletin's Sophia Chen interviews graduate student John Ahrens of Harvard University about challenges in bioprinting heart tissue. One challenge in particular is aligning the cells. Heart cells are narrow and rectangular in shape. In a natural heart, they line up in parallel to form aligned filaments. Those aligned filaments are built up into a larger tissue with more complex alignment. Cellular alignment correlates with heart function. The research team has programmed the bioprinter to make tissues that are aligned vertically, in a circular pattern, or in the shape of a chevron.  This study is published in Advanced Materials (doi:10.1002/adma.202200217). 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Adam Kubec at Swiss startup XRNanotech and research team member Marie-Christine Zdora of the Paul Scherrer Institut about their proof-of-principle of an x-ray achromatic lens. The lens consist of a focusing diffractive and a defocusing refractive optical element that achieves imaging of a range of wavelengths without having to move the sample. The researchers used two different diffractive lenses, one made from nickel and one with gold. To fabricate the refractive lens, they used a nanoscale 3D printing technique known as two-photon polymerization. This work was published in a recent issue of Nature Communications (doi:10.1038/s41467-022-28902-8).

Czemu służą nużeńce żyjące na naszych twarzach i jak się zmieniają na przestrzeni pokoleń? Czy nowe terapie oparte na bakteriach jelitowych mogą pomóc w leczeniu depresji? Czym jest pęseta akustyczna i do czego może służyć? Czy uda się wprowadzić powszechne, proste, tanie i szybkie badanie równowagi u osób starszych i właściwie po co to robić? Jak skuteczne i czy w ogóle są tak powszechne suplementy diety w zapobieganiu nowotworom i chorobom serca? O tym wszystkim opowiem w tym odcinku podkastu Naukowo :)Jeśli uznasz, że warto wspierać ten projekt to zapraszam do serwisu Patronite, każda dobrowolna wpłata od słuchaczy pozwoli mi na rozwój i doskonalenie tego podkastu, bardzo dziękuję za każde wsparcie!Zapraszam również na Facebooka, Twittera i Instagrama, każdy lajk i udostępnienie pomoże w szerszym dotarciu do słuchaczy, a to jest teraz moim głównym celem :) Na stronie Naukowo.net znajdziesz więcej interesujących artykułów naukowych, zachęcam również do dyskusji na tematy naukowe, dzieleniu się wiedzą i nowościami z naukowego świata na naszym serwerze Discord - https://discord.gg/mqsjM5THXrŹródła użyte przy tworzeniu odcinka:O'Connor EA, Evans CV, Ivlev I, Rushkin MC, Thomas RG, Martin A, Lin JS. Vitamin and Mineral Supplements for the Primary Prevention of Cardiovascular Disease and Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2022 Jun 21;327(23):2334-2347. doi: https://doi.org/10.1001/jama.2021.15650. PMID: 35727272.US Preventive Services Task Force, Mangione CM, Barry MJ, Nicholson WK, Cabana M, Chelmow D, Coker TR, Davis EM, Donahue KE, Doubeni CA, Jaén CR, Kubik M, Li L, Ogedegbe G, Pbert L, Ruiz JM, Stevermer J, Wong JB. Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2022 Jun 21;327(23):2326-2333. doi: https://doi.org/10.1001/jama.2022.8970. PMID: 35727271.Elana Spivack, "Beer might actually improve gut health study finds", https://www.inverse.com/mind-body/beer-improves-gut-health-studyY. Zeng et al., "Manipulation and Mechanical Deformation of Leukemia Cells by High-Frequency Ultrasound Single Beam," in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 69, no. 6, pp. 1889-1897, June 2022, doi: https://doi.org/10.1109/TUFFC.2022.3170074.Sophia Chen, "Forget Lasers. The Hot New Tool for Physicists Is Sound", https://www.wired.co.uk/article/acoustic-sound-waves-engineers-physicsAraujo CG, de Souza e Silva CG, Laukkanen JA, et alSuccessful 10-second one-legged stance performance predicts survival in middle-aged and older individualsBritish Journal of Sports Medicine Published Online First: 21 June 2022. doi: http://doi.org/10.1136/bjsports-2021-105360Najwyższa Izba Kontroli, https://www.nik.gov.pl/aktualnosci/system-opieki-geriatrycznej.htmlRoss Pomeroy, "10-second balance test is a powerful predictor of death for older adults", https://bigthink.com/health/balance-predicts-death-older-adults/Schaub, AC., Schneider, E., Vazquez-Castellanos, J.F. et al. Clinical, gut microbial and neural effects of a probiotic add-on therapy in depressed patients: a randomized controlled trial. Transl Psychiatry 12, 227 (2022). https://doi.org/10.1038/s41398-022-01977-zGilbert Smith,...

In this podcast episode, MRS Bulletin's Sophia Chen interviews Kenjiro Fukuda from RIKEN in Japan and Masahito Takakuwa of Waseda University about a technique to connect integrated electronics while maintaining their flexibility. They demonstrated the method on two gold electrodes. To make the two pieces of gold bond, the researchers treated the gold with water vapor plasma. The researchers used this technique to electrically connect the gold electrodes of an organic photovoltaic to an organic light-emitting diode without adding significant thickness, thereby ensuring the flexibility of the device. This study is published in Science Advances (doi:10.1126/sciadv.abl6228). 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Carla Gomes, Michael Thompson, and Max Amsler of Cornell University about their robot, SARA—Scientific Autonomous Reasoning Agent. Unlike commonly known artificial intelligence (AI) applications such as the neural networks that enable image recognition, SARA performs within a closed loop system through a type of AI known as active learning, which allows the system to reason without a lot of training data. Within 30 minutes, SARA figured out how to make delta phase bismuth oxide and cool it to room temperature, saving the research team two full days of experiments. 

In this podcast episode, MRS Bulletin's Sophia Chen interviews Zahra Fakhraai of the University of Pennsylvania on her group's research to better understand how a substance condenses into glass. They studied the liquid–liquid phase transition in vapor-deposited thin films of N,N0-bis(3-methylphenyl)-N,N0-diphenylbenzidine (TPD). They discovered a new high-density supercooled liquid phase in glasses deposited in the thickness range of 25-55 nm. Their findings could lead to more precise theoretical descriptions of glasses.  

In this podcast episode, MRS Bulletin's Sophia Chen interviews Nima Rahbar of Worcester Polytechnic Institute on the use of an enzyme, carbonic anhydrase, that initiates self-healing in concrete. The enzyme catalyzes calcium in the cement to react with carbon dioxide from the air to form crystals of calcite, which repairs cracks. Rahbar's research group has demonstrated how the material can heal millimeter-wide cracks. Ubiquitous concrete is responsible for 8% of human-made greenhouse gases, including that used in the repair of existing structures. Rahbar's work is expected to help reduce concrete's carbon footprint, while also speeding up the self-healing compared to the previously used bacteria-based methods. 

Sophia Chen of MRS Bulletin interviews Jennifer Dionne from Stanford University about the origin of photonic emissions in the quantum material hexagonal boron nitride (hBN). Read the article in Nature Materials. TranscriptSOPHIA CHEN: Many researchers are hotly anticipating quantum technology, a new paradigm that exploits the mathematics of quantum mechanics. But researchers are still developing the so-called quantum materials to build these devices and connect them in a future quantum internet. Jennifer Dionne, a materials scientist at Stanford University, is investigating one such material called hBN, or hexagonal boron nitride. hBN could be useful for quantum machines because it can be made to emit single photons of light to compute and transmit information. When you illuminate hBN with light the material will emit a spectrum of colors ranging from the red to the green. Dionne’s team wanted to understand what microscopic property or defect in the material was responsible for the different colors. JD: What we wanted to do was address where those different colors were coming from, because in a future quantum optical network, ideally you’d be able to control what color is coming out where and be able to use that wavelength multiplexing of photonic communications.SC: To identify which light came from what defect, they used a combination of two different techniques. JD: By interrogating with an optical microscope, we can see broadly where there were different defects and use the electron microscope to zoom into those defects and map them out with much higher resolution and to also look at their atomic scale structure.SC: They were able to identify that the colors arise from four classes of defects in the hexagonal boron nitride.JD: So we now know with certainty there are at least four different types of atomic defects that are responsible in the main spectral windows. If you want light predominantly in the green, you would use one type of atomic defect. If you want light in the red, you use a different type of atomic defect.SC: Combining their experimental studies with theory, Dionne’s team was able to deduce more details about the defects themselves.JD: We found that it seems like most of the defects that are emitting are not simple atomic defects, but rather complexes. So hexagonal boron nitride, like I said, is this layered material. You need to think not only about a missing atom in one layer but perhaps a missing atom or a substitutional atom in a neighboring layer, and basically a series of missing atoms between one layer and a next form something like its own independent molecule in the material.SC: By understanding the specific defects in a material, eventually, researchers should be able to implant specific impurities that can be independently controlled to emit light in a quantum device.JD: We’re excited to get higher spatial imaging resolution and start positioning those emitters and see how we might be able to modulate the emission, to be able to turn the emission on off, which would be the same in a transistor. You want to be able to turn the electrical current on and off and be able to get gain. Trying to create a suite of quantum optical devices based on these emitters would be very exciting and next step.SC: But this technique, where they combine optical and electron microscopy to study quantum materials, is useful beyond just hexagonal boron nitride.JD: More so than learning about hexagonal boron nitride, I think the significance of our paper is that it provides a technique to be able to do this correlation of the atomic scale structure of quantum materials with their optical properties.

Sophia Chen of MRS Bulletin interviews Stephen Balmert of the University of PIttsburgh about a patch delivery method of a vaccine to counter COVID-19. Read the article in EBioMedicine.TranscriptCHEN: To prevent the spread of Covid-19 in the long term, we will almost certainly need a vaccine against the disease. Stephen Balmert, a biomedical engineer from the University of Pittsburgh, is part of an international collaboration that has made such a candidate vaccine for Covid-19. They’ve tested their vaccine in mice and gotten promising results. BALMERT: I think everybody really wants to know, when is this going to be in humans? We’re putting together [a form] to get approval from the FDA to begin a clinical trial. SC: Under the microscope, the pathogen resembles a sphere adorned with spikes, known as spike proteins. Balmert’s vaccine is made of these spike proteins. To produce the spike, they introduce the genetic instructions for making the proteins into human embryonic kidney cell lines. These cells make the proteins. Then, the idea is to introduce the spike proteins into the human body, which teaches the immune system to recognize these proteins and produce antibodies that neutralize the virus. Their Covid-19 vaccine piggybacks off previous research on a similar coronavirus. Balmert’s colleague, Andrea Gambotto, had previously studied the MERS virus in his lab. SB: They had already identified at that point there’s a particular part of the virus, which is called the S protein or the spike protein, they’d identified that was a good target for vaccines. SC: Targeting the spike protein is a popular approach. But Balmert’s team uses a distinctive delivery method. Instead of injecting the vaccine via the traditional needle, they package their vaccine as a small, fingertip-sized patch covered in very small, short needles. The needles are made of a material called carboxymethyl cellulose, a hydrogel that dissolves in the skin. Each one is 225 µm in width, 750 µm in length, with a pointy tip shaped like a tiny Washington monument. SB: Each of those needles has the vaccine in the tips, so in the pyramidal part at top, and there’s a flat backing underneath that you use for the application. We say the application of the microneedle feels a little bit like Velcro, the hook part of the Velcro. So you can feel the pressure, but it’s not painful in the sense of a traditional injection is.SC: In addition, the patch deposits the spike proteins into the skin, as opposed to muscle like many traditional vaccines. This offers potential benefits as well. The skin contains a high concentration of immune cells because it protects the body from foreign particles. SB: So you have potentially somewhat of a dose sparing effect, where you get a stronger immune response with the same dose. Or you can use less dose for the same immune response than a regular injection. In that sense, it requires potentially less vaccine. SC: They could also be easier and cheaper to store compared to other vaccines. SB: With these microneedle arrays, the carboxymethyl cellulose in the hydrogel material around the vaccine itself kind of maintains the structure of the vaccine. It maintains its bioactivity so you don’t have to keep them refrigerated. You don’t have to have refrigerated shipping or store them in a refrigerator necessarily, so that’s another potential advantage. SC: They’ve published peer-reviewed results indicating the vaccine produces antibodies in mice. Now, they’re running tests to confirm that their results are reproducible and are working to gain approval from the Food and Drug Administration to begin clinical trials in humans.

Sophia Chen of MRS Bulletin interviews Pelayo Garcia de Arquer of the University of Toronto in Canada about a catalyst-ionomer architecture his group designed to quickly convert CO2 into useful hydrocarbons. Read the abstract in Science. TranscriptSOPHIA CHEN: The challenge for the world to reduce carbon emissions is steep. To reduce these emissions in the long run, some scientists believe it will be necessary to extract carbon dioxide from the air. But once you extract all that carbon dioxide, what do you do with it? Pelayo Garcia de Arquer, a materials scientist at the University of Toronto in Canada, has a potential answer. He’s working on technology for converting carbon dioxide into useful hydrocarbons, such as plastics, fabrics and fuels that are now produced by the petrochemical industry. In other words, he’s trying to turn lemons into lemonade. PELAYO GARCIA DE ARQUER: Our approach is to decarbonize this process by taking existing CO2 in the atmosphere, in the exhaust of an industry for example, and using electricity, which could come from renewables, and using water, and upgrade the CO2 into other molecules that can be used in these production systems, for example upgrading CO2 into ethylene, which is the precursor to a lot of polymers. SC: To convert carbon dioxide into ethylene, they pump CO2 gas to a spongelike catalyst interface, where the CO2 breaks down and ultimately reacts with water and an electrolyte. But it’s difficult to orchestrate this reaction quickly and efficiently, at the rates needed to make this technology economically viable. On their own, the individual reactants don’t tend to move to the right location very quickly. PGDA: You need to have all the ingredients of your cake in the right place and in the right time. SC: The difficulty is that CO2 does not like to dissolve in water. It also tends to undergo undesired reactions with the electrolyte to produce hydrogen molecules, for example. This makes the reactions proceed slowly. So their lab’s innovation was to include an extra ingredient on the surface of the catalyst known as an ionomer, a polymer that conducts ions. The ionomer had both hydrophobic and hydrophilic parts, which in effect created distinct channels for carbon dioxide, water, and the other ingredients to travel through separately to reach the catalyst. Monitoring the electric activity in their system, which is an indication of how quickly the chemical reaction is proceeding, they measured an electric current density of more than one ampere per square centimeter, which Garcia de Arquer says is about 10x improvement compared to the state-of-the-art just 2 years ago. PGDA: This is enabled, we believe, because of this phenomenon, like CO2 can travel faster through these more dry channels that do not have water.SC: They also achieved an efficiency of 45%, meaning that 45% of the energy they put in created the ethylene. It’s not clear yet what metrics will make this system commercially viable, as the economics depend on many outside factors, such as the cost of electricity. But Garcia de Arquer says that the field is moving closer to a deployable technology.PGDA: Achieving current densities in the realm of amperes per square centimeter, together with energy efficiencies above 60%, that’s the threshold we predict with the numbers we have right now, where we think things will become more and more interesting.

Sophia Chen of MRS Bulletin interviews Dan Walkup of the National Institute of Standards and Technlogy about an unusual concentric quantum dot structure created in graphene. Read the abstract in Physical Review B .TranscriptSOPHIA CHEN: Physicist Dan Walkup has a mystery on his hands. Working at the National Institute of Standards and Technology in Gaithersburg, Maryland, his team has engineered a strange phenomenon in the 2D material graphene using a scanning tunneling microscope, or STM. They created the phenomenon by accident playing around with the STM, whose very sharp tip manipulates single atoms on a material. In the graphene it created a quantum dot (QD). DAN WALKUP: Historically we weren’t trying to study coupled QDs per se. We were trying to figure out how to tune the properties of the graphene with STM tip. In that way we came eventually to this QD study. SC: You can visualize the QD as an island in the graphene, where electric charges are confined and isolated from the rest of the material. At the QD, negative electrons gather around positive electron holes. They can also do the charge inverse of this, where the positive holes go around a negatively charged nucleus. From this, you might get the sense why QDs are sometimes known as artificial atoms. Like atoms, quantum dots consist of one type of charge going around a nucleus of the opposite charge. The researchers have taken the graphene, stuck it on a substrate of hexagonal boron nitride, and manipulated the electric charges with the STM inside these two materials to create the QD. DW: We create a little pocket of charge in the hexagonal boron nitride, and that charge pocket attracts oppositely charged electrons in the graphene and makes a little charge pocket in the graphene, which becomes a QD. SC: But this isn’t your garden variety QD. The geometry of this particular island has never been seen in graphene. By using the STM and applying a strong magnetic field to the material, Walkup’s team has made a nested QD, one island of charge stacked on the other. From overhead it looks like a bulls’ eye, with one island of charge at the center, and another forming a ring around it. DW: The two dots are like the two tiers of this wedding cake.SC: They’re two concentric quantum dots: one dot is in the center and the other dot is the ring around the first. These two structures are distinct quantum dots because electrons from one island are generally confined to that island. Walkup’s team ran some experiments in which they added electrons to each quantum dot. They did this by applying a voltage to the back of the material, causing electrons to move toward each dot. The researchers can then monitor where the electrons go using the scanning tunneling microscope. And what they found was puzzling. They found that as they added electrons to either of the two quantum dots, they behaved in a way that can’t be explained by accepted models of quantum dot physics. Walkup says you would expect the two dots to repel each other as you add electrons to them, since negative charges repel each other. But the inner dot only cared about its own charge. It did not care about the charge of the outer dot. Whereas the outer dot responded to the combined charge of both dots. They want to figure out why. DW: Part of this paper is an open invitation to the theorists in the world to figure out why it is this way instead of some other way. SC: A better understanding of the basic physics of this bizarre quantum dot configuration could help the development of applications such as quantum computing, in which information is stored in the way quantum dots share electrons. This work was published in a recent issue of Physical Review B.

Sophia Chen of MRS Bulletin interviews Tina Škorjanc, a PhD student at New York University in Abu Dhabi in the United Arab Emirates, and her professor Dinesh Shetty at Khalifa University, Abu Dhabi, about porphyrin–based covalent organic frameworks they developed that remove the toxic substance bromate from drinking water. Read the article in Chemical Science. TranscriptSOPHIA CHEN: Drinking water: Whether it’s out of the tap, the refrigerator, or a bottle, we expect it to be clean. Water treatment plants oblige, with a complicated sequence of filtration and purification processes. During a last purification step, the treatment plants add ozone to disinfect the water. The ozone removes odor, color, and taste, and it does this all quickly. But a potential dangerous side effect of the ozone turns harmless, naturally occurring bromine ions in the water into the toxic substance bromate. Tina Škorjanc, a PhD student at New York University in Abu Dhabi in the United Arab Emirates, is working on methods to remove bromate from drinking water.TINA ŠKORJANC: It has been linked to a whole series of health conditions in humans and has been linked to cancer, which is why we think it is important to remove it.SC: Škorjanc’s team has developed a new material that can remove bromate much faster than any other existing method. TS: We really outperformed other materials which were of different classes. This list included inorganic materials, activated carbons, metal organic frameworks, a couple of other polymers, our rates really surpassed the ones reported for these other materials. SC: Dinesh Shetty, Škorjanc’s colleague and a professor at Khalifa University, also in Abu Dhabi, says that their group is the first to create a covalent organic framework specifically for bromate removal. DINESH SHETTY: Compared to normal polymers, covalent organic frameworks are ordered structures. It has defined structure, you can study exactly what is happening within this framework, you know exactly where bromate is going, how it is interacting with this material. SC: Bromate likes to stick to this material, because the material is positively charged and electrostatically attracts the negatively charged bromate. DS: If you think about other covalent organic frameworks, you have to synthesize COF first and then introduce positive charges. We are reducing one step, synthetically, if you think about it. TS: We can do our bromate adsorption experiment, take that material which has bromate on its surface and in its pores, remove those molecules by simple treatment with sodium hydroxide followed by neutralization, and we can reuse that same batch for bromate adsorption again. What’s important in the second step is the efficiency doesn’t drop. We’re still able to remove the same amount of bromate that was removed in the first cycle. SC: It’s still unclear whether this material will be economically viable for adoption by existing water treatment plants. But their work opens the door to further development of covalent organic frameworks that remove bromate. And in the meantime, their team is working to figure out how to scale up their experiment and eventually test it in a water research center in Abu Dhabi. DS: We are dealing with something which can directly impact society. If our plan works, if it becomes water purification material for bromate removal, we are helping millions all around the world. That’s real motivation for us. SC: My name is Sophia Chen from the Materials Research Society. Follow us on twitter, @MRSBulletin. Don’t miss the next episode of MRS Bulletin Materials News – subscribe now. Thank you for listening.

Sophia Chen of MRS Bulletin interviews Ron Milo of the Weizmann Institute of Science in Israel about a strain of E. coli his team developed that generates all its biomass from carbon dioxide. Their work was achieved through a technique called adaptive laboratory evolution, that is, evolutionary selection. Read the article in Cell. TranscriptSOPHIA CHEN: Inside a lab at the Weizmann Institute of Science in Israel, biologist Ron Milo and his team have engineered a strain of E.coli with an unusual diet. Natural E.coli is a heterotroph, meaning that it can only consume organic carbon compounds—like glucose. But Milo’s team converted the bacteria into an autotroph, an organism such as a plant that can consume inorganic carbon. They essentially changed the bacteria’s metabolic process. RON MILO: What we did in this study is show that we could take an organism of the second type, a heterotroph, in this case E.coli, that is used to having its diet coming from glucose in the media, and being able to transform it into the first type, the autotrophs, which build all their biomass directly from CO2. SC: To do this, Milo’s team had to enable E.coli to perform carbon fixation. Carbon fixation is a capability found in plants where inorganic forms of carbon are converted into organic compounds. This process involves first by adding electrons to the inorganic carbon, or reducing it, which allows the carbon to form an organic molecule. Then, the organic carbon is converted into biomass such as proteins and carbohydrates inside the cell. They did this by adding some genes into the bacteria’s DNA. One gene, for example, enabled the E.coli to reduce the carbon by taking electrons from a compound called formate. They also put in other genes. RM: So we put in the gene that takes carbon dioxide and incorporates it into biomass. It’s a gene called rubisco. We also put in a gene that builds a substrate for rubisco, it’s called PRK. SC: The engineered bacteria still ate sugar, so to make bacteria that ate only CO2, they turned to a technique known as adaptive laboratory evolution. They placed the engineered bacteria in a container with very little sugar and a high concentration of CO2, an environment which basically starved the cells. In this low sugar environment, they let the bacteria reproduce several hundred times for nearly a year. Eventually, they found that these later generations of E.coli generated all their biomass from CO2. RM: The process of carbon fixation aims to find ways to deal with the challenge of how do you produce transportation fuels that will not harm the environment as well as how to increase the yields in agriculture, and more generally, to see if there’s ways to sequester CO2 from all sorts of concentrated sources or even directly from the air. SC: The bacteria produced CO2 in addition to consuming it. In total, it created a net gain of CO2. So in its current form, the bacteria would not be useful for many applications. But they’ve come a long way since Milo started the project about a decade ago. RM: I remember when I presented this work, people thought it was somewhere between naive and crazy to think that one could actually change a heterotroph into an autotroph. We did most of our experiments in an atmosphere of 10% CO2. We could also show we could grow bacteria in lower CO2 levels of say, about 1 percent. But what we have in the atmosphere around us is about 400 parts per million, and we want to see if we can evolve the bacteria to grow in that. SC: Thank you for listening.

Sophia Chen of MRS Bulletin interviews Frankie Rawson of the University of Nottingham, UK, about wirelessly manipulating the electrical behavior of living cells. His research group does so by applying an external voltage to Au nanoparticles inserted into the cell. The voltage causes a molecule attached to each Au nanoparticle to undergo a redox reaction, in which atoms give up or accept electrons from each other. Read the abstract in Applied Nano Materials.TranscriptSOPHIA CHEN: Tiny electrical currents flow in many parts of the human body. For example, ions moving inside cells or crossing cell membranes. Many instances of these electrical currents occur because of a type of chemical reaction in the cell known as a redox reaction, in which atoms give up or accept electrons from each other. FRANKIE RAWSON: Ultimately, redox reactions underpin how cells make energy. SC: Frankie Rawson is a bioengineer at the University of Nottingham in the UK. He’s designing materials that can be placed into a live cell—and modify its electrical behavior.FR: Biology is largely underpinned by electrical behavior, and we’re starting to realize that if we can merge and develop materials that seamlessly integrate with that biology we can control the electrical input and output on a really targeted scale. SC: In the past, to manipulate a cell’s electrical behavior, researchers would have to place nanowires inside the cell. Rawson and his team have recently demonstrated that they can do this wirelessly. Essentially, they drove a redox reaction in the cell, and they did it like this. They inserted modified gold nanoparticles into the cell. Then, they applied an external voltage. They applied a relatively low 150 volts compared to the kilovolts used in prior experiments. This basically causes a molecule attached to each gold nanoparticle to undergo a redox reaction. The nanoparticle helps direct the external electric field. FR: The gold nanoparticle acts as an electrical antennae, effectively. SC: The researchers confirmed that the redox reaction occurred using two different methods. First, they illuminated the molecule attached to the gold nanoparticle, a type of molecule known as zinc porphyrin, with yellow light and monitored its fluorescence. Zinc porphyrin’s fluorescence changes depending on its number of electrons. When the molecule gains an electron, its fluorescence dims, signifying that the redox reaction has occurred. At the same time, the researchers also performed a measurement known as cyclic voltammetry, in which they measure electrical behavior of the nanoparticle while changing an applied voltage. These two methods collectively indicated that they had triggered a redox reaction at the surface of the gold nanoparticle inside the cell wirelessly. FR: What that means is, that’s moving toward that step where you don’t need a physical wire connection inside the cell to actuate electrochemical behavior inside the cell. SC: Ultimately, the bigger goal is to use the zinc porphyrin redox reaction to drive other reactions inside the cell. Rawson wants to trigger redox reactions in a cell that would kill it. FR: If everything goes to plan, the research hypothesis is that you can use this as a bioelectronic drug. You put this in an organism; you can target the electric field in a location in that organism, and switch on cell death. Our hypothesis is to use this to kill cancer cells. SC: For more news, log onto MRS Bulletin and follow us on twitter.

Sophia Chen of MRS Bulletin interviews Jason Smith of the University of Oxford about using ultrashort pulse laser processing to engineer nitrogen-vacancy centers in diamond that can then perform as qubits in quantum computers. Read the article in Optica.TranscriptSOPHIA CHEN: Quantum computers promise to be much faster than conventional computers at solving certain problems, such as in chemistry and machine learning. But it’s still unclear what material to build them from. One promising candidate is a type of synthetic diamond containing an impurity known as a nitrogen vacancy center, or NV center. These impurities consist of a nitrogen atom and a vacancy, next to each other, inside a lattice of carbon atoms. Jason Smith, a materials scientist at the University of Oxford, explains how the defects would work as quantum bits, or qubits.JASON SMITH: When you put these two defects next to each other, the nitrogen and the vacancy, they form a stable complex called the NV center, and these behave like trapped atomic systems within the diamond lattice, they have well-defined electron orbitals and energy states.SC: Using lasers, you can manipulate the NV center into one of two energy states that represent 1, 0, or a superposition of both. Once programmed into quantum states, the NV centers can be manipulated to run computations. However, it’s still difficult to quickly and consistently synthesize NV centers inside diamond. JS: The challenge of creating NV centers is really of creating where you want them within a piece of diamond, and in the conditions that make them perform well as qubits for a quantum computer or quantum device.SC: So Smith and his team have come up with a new technique for implanting these impurities where they want them in a diamond. The technique works like this. They start with a synthetic diamond that already contains nitrogen impurities. They beam an extremely short laser pulse, less than a trillionth of a second long, at the diamond, which knocks out a carbon atom in the diamond lattice, creating a vacancy. Then, they use a less energetic laser to heat up the diamond in a localized spot. JS: We’re annealing the diamond very locally just within the focal spot of the laser. We’re essentially turning up the temperature of the diamond, turning up the heat, encouraging those vacancies to diffuse around the diamond.SC: The vacancies migrate around the diamond randomly. But the researchers sense when they have moved next to a nitrogen atom to create an NV center. They detect this by illuminating the diamond with another laser that causes the NV center to fluoresce. When they detect this fluorescence, they know the NV center has formed.JS: The fluorescence that comes out has a particular spectral signature to it.SC: This technique is much more consistent compared to their previous methods, he says. In the past, they annealed the diamond in an oven to create the NV centers. At most, this only created a defect in the intended lattice site 37% of the time. Using this new technique, they can create an NV center in the intended site just about 100% of the time. Next, they want to try this technique on a synthetic diamond with a lower concentration of nitrogen. The diamond’s nitrogen concentration in their experiment was too high and would create too much noise for actual quantum computing applications. In a diamond with less nitrogen, they want to see if they can make the NV centers at the same rate. The goal, eventually, is to use these techniques to create the much larger processors that are needed for useful quantum computations. Smith says that theoretically, NV centers in diamond should be easier to scale than other types of qubits.JS: A million NV-centered qubits/cm2, the basis for a processor.

Sophia Chen of MRS Bulletin interviews Nicholas Butch of the National Institute of Standards and Technology about the evidence of topological states found in UTe2. These could possibly function as topological qubits, a favorable “hardware” for quantum computers that should not require error correction. Read the article in Science. TranscriptSOPHIA CHEN: Recently, you may have heard that Google’s quantum computer executed an algorithm a billion times faster than a conventional computer. But their machine is far from being broadly useful. No existing quantum computer is. One of the biggest challenges that the technology faces is that the computer hardware—its so-called qubits—interacts with the environment in unwanted ways. This results in computing errors, and no one knows how to correct these errors yet. That’s why researchers are investigating new materials for building qubits that might avoid these errors altogether. Nicholas Butch, a physicist at the National Institute of Standards and Technology, researches a class of materials that can be manipulated into something known as a topological state. A topological state occurs when the material’s electrons are collectively manipulated to behave in a specific correlated way.NICHOLAS BUTCH: Topological states are in principle robust, or at least more strongly defendant, against that kind of coupling to the noise in the environment.SC: Materials that harbor these quantum states could then be built into topological qubits, which shouldn’t need error correction. So you could build a comparably powerful computer with much fewer qubits compared to devices like Google’s quantum computer. The company Microsoft is pursuing a quantum computer made of topological qubits. However, it’s been difficult to create these quantum states. So far, researchers have only found indirect evidence of topological states in materials. Recently, Butch and his colleagues synthesized another promising candidate, UTe2, which looks like a silvery crystal. NB: These are basically the size of typical, let’s say, table salt grains.SC: While the researchers haven’t directly confirmed that UTe2 is a topological material, they’ve observed properties in it that are associated with topological states. The researchers ran a current through the crystal and found its resistivity went to zero as they cooled it to 1.6 Kelvin. NB: Even though we know about thousands of superconductors, there’s a very short list of spin triplet superconductors that we know about.SC: They still have to confirm this, but they suspect it’s this rare type because its properties differ from those of typical superconductors. The heat capacity of typical superconductors usually goes to zero as the material becomes superconducting, but this material’s heat capacity does not. In addition, most superconductors lose their superconductivity if you put them in a magnetic field of around 1 Tesla. In this material, it took 35 Tesla. These properties hint that the electrons in UTe2 pair up in different configurations than they do in a typical superconductor. Theory suggests that if a material shows this distinctive electron pairing, it should also harbor topological states. Butch and his team plan to study how the material responds under increasingly high pressure. They also want to definitively find the topological states. They’ve also found that once you suppress the material’s superconductivity in a 35 Tesla magnetic field, that if you turn the field even higher, the superconductivity comes back between 40 and 60 Tesla. They don’t know why.NB: We’re in the midst of trying to determine exactly how weird it is.

Sophia Chen of MRS Bulletin interviews Jason Azoulay of the University of Southern Mississippi about his conjugated polymer semiconductor, a promising candidate for technologies that integrate both conventional electronics and spintronics. Read the article in Science Advances.TranscriptSOPHIA CHEN: Conventional electronics like your smartphone or computer use the voltage and current of electrons in a material to encode and transmit information. Spintronics aims to exploit the quantum spin of those electrons as an additional signal. Jason Azoulay of the University of Southern Mississippi, develops materials that might be useful for spintronics combined with conventional electronics. JASON AZOULAY: People are looking at controlling electron correlations and spin and magnetism for emerging types of technologies. There’s a wide variety of technologies, whether it’s something as far off as quantum computing or new types of magnetic materials, or even multifunctional activities where you effectively combine things like spin degrees of freedom with charge transport or some type of optoelectronic functionality. SC: For spintronics, materials have to exhibit strong magnetism known as a high-spin state. On the microscopic scale, this means that the electrons involved in chemical bonds in the material need to have their spins aligned in the same direction. It has been difficult to make organic high-spin materials that are stable at room temperature. Azoulay and his colleagues have made such a material. JA: We’ve tested it for a while, and it’s a rock. It’s very stable. SC: The material is a type of macromolecule known as a conjugated polymer, meaning that its constituent molecules are stitched together by a backbone of shared electrons. In the material’s ground state, these electrons align in pairs, thereby collectively creating the desired “high spin state.” JA: The best way to think about it is that we made a polymer organic magnet. SC: The material, which looks like a black powder, behaves like a semiconductor. The flow of these electrons through the material can be turned on and off according to its bandgap energy. In addition, the polymer’s bandgap energy is easy to tune. It consists of alternating molecules of cyclopentadithiophene and thiadiazoloquinoxaline, which are an electron donor and acceptor, respectively. Because of this tunable bandgap and its high spin state, the material is a promising candidate for technologies that integrate both conventional electronics and spintronics. The researchers found that a minimum of 13 donor-acceptor pairs were required in order to create the electron interactions that produce the high-spin state. JA: We’re working on next generation versions of this material. The questions are, can we increase the conductivity? Can we increase the magnetic properties? Can we control the electronic topology? Can we control the properties of the spins. Another fun aspect of it as well, how are these going to interact with electromagnetic fields or stimuli or light. We’re studying their properties because they’re fundamentally new materials.

Sophia Chen of MRS Bulletin interviews Renkun Chen of the University of California, San Diego about his flexible thermoelectric devices that can provide personalized cooling and heating effects in clothing. Read the article in Science Advances.TranscriptTranscriptSOPHIA CHEN: If you’ve ever had to pay an air conditioning bill during the summer, you know how expensive it gets. Renkun Chen is a mechanical engineer at UCSD with an energy-saving idea: clothes with adjustable temperature. He and his team have designed and fabricated a material you can wear that directly cools the skin. RENKUN CHEN: Instead of having a centralized air conditioning system in a building, where you need to cool down a large volume of space for building occupants, we use our system to cool down a much smaller volume at a personal level. By doing so, we can save energy by at least an order of magnitude. SC: The power consumption per person of a conventional AC system is a few kilowatts, he says. Whereas personalized cooling, like a temperature-regulating outfit, uses tens of watts. Chen isn’t the first to invent clothes that directly cool your skin. For example, you can buy shirts right now that circulate icy water to cool you off. But his team’s design uses a thermoelectric material, which cools via a distinctive mechanism known as the Peltier effect, which creates cooling by passing an electric current between the junction of a semiconductor and metal. When you reverse the current, you create a heating effect. This can achieve much subtler temperature control than the wearables that are commercially available. Chen’s device can cool and heat. RC: It’s really like the thermostat in the air conditioning system. You can really set the skin temperature. SC: The highest performing thermoelectric materials are rigid, so Chen’s team needed to configure these materials to make a flexible, wearable device. They used two different commercially available thermoelectric materials. These materials consist of two bismuth telluride alloys: a p-type semiconductor alloyed with antimony, and an n-type semiconductor alloyed with selenium. Both alloys are connected to metal electrodes, and they create a cooling effect by making an electric current flow from the metal to the p-type material, or from the n-type material to the metal. Reversing the direction of the current causes heating. To make their system flexible, Chen and his team made these alloys into pillars and sandwiched them between two sheets of Ecoflex, a flexible silicone rubber. RC: Even though the pillars by themselves are rigid, the entire device is flexible because of the overall architecture. SC: They wanted the entire layer of each sheet of Ecoflex to keep at a uniform temperature. So to achieve this, they embedded aluminum nitride particles to increase its thermal conductivity. They also kept a 4 mm air gap between the two sheets for insulation. When the ambient temperature was between 22°C and 36°C, they could maintain the wearer’s skin temperature at 32°C, which they defined as a condition of thermal comfort. Chen wants to develop this into a therapeutic device for people who have medical conditions that make it difficult for them to regulate their skin temperature. RC: There are patients who are very sensitive or prone to overheating with certain health conditions like multiple sclerosis, or people who are genetically not able to sweat, they are prone to overheating. There are certain occupations, outdoor construction workers or fire fighters, and people who are doing outdoor activities, like athletes for example. For this kind of application, I think our device will also provide good thermal comfort solution.

Sophia Chen of MRS Bulletin interviews Alex Hexemer of Lawrence Berkeley National Laboratory in California, and Daniela Ushizima and Shuai Liu of the University of California, Berkeley about their design of multiple Convolutional Neural Networks (CNN) to classify nanoparticle orientation in a thin film by learning scattering patterns. Read the article in MRS Communications. Transcript SOPHIA CHEN: Materials researchers come from around the world to study their samples in the beamline at the Advanced Light Source facility, located at Lawrence Berkeley National Laboratory in California. Alex Hexemer, a senior scientist at the facility, tells me that they’re currently upgrading the machine, so that it can take much more data, much more quickly. HEXEMER: The amount of data you’re going to create is so large that A, you can’t take it home on a hard drive anymore, nor can you start looking at the data anymore. It’s just too big. Some of the detectors here are going to run at thousands of frames a second. It becomes unmanageable from a human point, so we have to transition to more automated approaches.CHEN: So Hexemer and his collaborators decided to try a machine learning approach to quickly classify and process x-ray images. To develop their image classification algorithm, they worked with frequency-space pictures of thin films made of polymers, about 100 nm thick. Scientists image these thin films at the facility. They consist of intricate geometrical patterns on the nanometer scale, which researchers try to engineer to create specific materials properties. For example, Hexemer explains that one future application is a printable solar panel. In the future, people might be able to print photovoltaics made of thin film polymers. But first, they need to figure out what nanometer structures work the best.HEXEMER: To try to understand the efficiency of the material, we have to understand the morphology.CHEN: They came up with seven different categories of thin film patterns. One of Hexemer’s computer science collaborators, Dani Ushizima, explains that they had to show the computer millions of examples.DANIELA USHIZIMA: This neural network base will build a mathematical model that will represent the different patterns.CHEN: They found they could classify images successfully into the seven categories 94% of the time. USHIZIMA: The training process might take a long time—hours. But the feedback, to classify a scattering pattern, this is coming on the millisecond. CHEN: The images they classified were simulations of thin films rather than real data. HEXEMER: We want to have better and better simulations close to real and partially disordered systems. And that is very difficult. CHEN: The team brought together experts from materials science and computer science. Shuai Liu, a member of the team, says to expect more collaborations between the disciplines.SHUAI LIU: We point out a very important direction in future research is to combine machine learning, which has been well developed in recent years, with a lot of characterization techniques.CHEN: My name is Sophia Chen from the Materials Research Society. For more news, log onto the MRS Bulletin website at mrsbulletin.org and follow us on twitter, @MRSBulletin. Thank you for listening.

Sophia Chen of MRS Bulletin interviews Barbara Mazzolai and Edoardo Sinibaldi of the Italian Institute of Technology about their robot made from two types of polymers, enabling it to extend and retract like the tendrils of a plant. Read the article in Nature Communications. TranscriptSOPHIA CHEN: Barbara Mazzolai is designing robots inspired by plants. Recently, she and her research team at the Italian Institute of Technology have made a robot that looks like a plant tendril, similar to the ones that ivy plants might use to climb a trellis. She says they want to develop a robot that can explore an unknown area just like a plant does. BARBARA MAZZOLAI: Plants could be the model to develop the robot for a very harsh environment, for colonizing a very difficult environment, to explore a harsh situation. Tendril is one of the ways, one of the strategies that they use to anchor the body. CHEN: The robot doesn’t just look like a plant tendril. It also moves according to the same mechanism as in nature. Both the robot and the plant move fluid around inside them to extend their tendrils. Both the plant and robot push or extract fluid from inside the tendril by exploiting the process of osmosis. Mazzolai’s colleague, Edoardo Sinibaldi, explains how it works in their robot. If you can imagine the curly tip of the robot tendril, that curl is attached to a longer tube contained within a special sleeve made of active carbon cloth electrodes. This sleeve is placed in a solution containing lots of ions. EDOARDO SINIBALDI: In our implementation we used sodium sulfate. It’s a common electrolyte, and it’s very stable, and it’s not toxic. CHEN: They’ve made the tendril using two types of plastic. One type, called polysulfone, is permeable to water. Water can flow across this plastic barrier through pores about 50 nm in size. Imagine this part of the tendril, which is soaking inside the solution within the carbon cloth sleeve. At equilibrium, the ion concentration is the same inside and outside the tube. But Sinibaldi applies a voltage to two electrodes on the cloth sleeve, to make ions collect on the electrodes. This causes the liquid outside the tube to have a lower concentration of ions than inside the tube. This concentration gradient causes water to rush into the tube. This inflow of fluid stiffens the tendril tip, making it extend. The tendril tip is made of another type of plastic, ethylene terephthalate, coated with Al, which has been fabricated to achieve the necessary stiffness.SINIBALDI: This is the basic fluid transport used by plants to, let’s say, swell cells and tissues in a coordinated manner and consistently stiffen tissue while it’s inflating and decreasing the stiffness of tissue while deflating. CHEN: It takes about a milliliter of fluid to extend the robot tendril. They were able to coil the tendril 500 degrees in 25 minutes. And they can reverse the coiling or uncoiling as needed. Mazzolai also points out that the whole robot, including the tube and the carbon cloth, are made of flexible, soft material with tunable stiffness. These are properties that could be useful for medical applications. MAZZOLAI: This is the challenge of the soft robotics community, developing something that can operate in the body without any damage to the human, and at the same time to be able to operate and change the stiffness. CHEN: Mazzolai has also chosen to make plant-like robots because they have unique adaptations for exploring and functioning in harsh conditions. She thinks that they could be useful for exploring new planets, or in more mundane applications on Earth. MAZZOLAI: These robots, they can move inside very narrow spaces for exploration for recovering objects in wells, or moving debris after a disaster.

Sophia Chen of MRS Bulletin interviews Zhenan Bao of Stanford University about her research team’s development of a biomimetic soft electronic skin (e-skin) composed of an array of capacitors capable of effectively measuring and discriminating shear force in real time. Read the abstract in Science Robotics. CHEN: Zhenan Bao is a professor at Stanford University whose research team developed this robot. She says the key design of the robot is a network of force sensors on its fingertip that tell the robot when to retract. BAO: Without sensor feedback, the robot would not know how much it can press on an object before it should stop. CHEN: They’ve also shown that the robot can respond to feedback to place a ping-pong ball into an arrangement of different round holes. She says that this type of tactile robot could be useful in all sorts of situations.BAO: Any robot that will need to have the ability to manipulate objects and being in contact with objects will need this type of sensing feedback.CHEN: Basically, it works because they’ve invented a stretchable electronic skin covered in sensors that can sense force from multiple directions. It can sense forces perpendicular to the skin, or normal force, as well as forces parallel to the skin, known as shear force. And both forces are necessary for grabbing, holding, and placing objects. Try it. Grab a coin or something between your fingers—you’ll notice how you need to apply pressure to hold it, but also sense shear force to keep it from sliding. Previously, electronic skins couldn’t sense shear force very effectively. The sensors were fragile and they also could only be placed sparsely on the robot. But Bao has figured out a way for the robot to sense the shear force, and she’s placed those sensors at high density on the skin. The more sensors crammed onto a surface, the better you can control the robot’s sense of touch. Bao says some of the tactile properties of the electronic skin are comparable to the sensitivity of human skin. For example, if the skin experiences a shear pressure increase of 1 pascal, the electronic signal output of the skin will triple in size. 1 Pascal is about the pressure of a dollar bill resting on a table. BAO: We are able to use fingertips to feel the most delicate texture and structures on the surface. CHEN: In fact, to create this electronic skin, she’s borrowed a design element from human skin itself, a structure called the spinosum, which lies between the epidermis and dermis. They’re these little hill-like structures for sensing the direction a force is coming from.BAO: If you add this hill-like structure, then depending on whether the force comes from left side or right side, because this dome or hill will be pressed from an angle, then only mechanoreceptor that’s on the opposite side of the direction of the force will be pressed and activated. This gives us a sense of direction of the shear force. CHEN: The hill structures are pretty small—a fraction of a millimeter in size—and she can pack them densely onto the electronic skin. But if you zoom in even further, you can see the other key structural design on their electronic skin. Bao’s group has fabricated tiny pyramids, tens of microns wide at the base. BAO: After a force is applied, these pyramids allow the elastic material to bounce back to its original shape once the force is removed.CHEN: And in the future, Bao wants to borrow even more design elements from human physiology. She wants the sensors to pre-process some of the signal, like neurons do. BAO: This neural-like signal processing lets humans gather a large amount of information and train our brain to learn the patterns of information with very little consumption of energy.

Sophia Chen of MRS Bulletin interviews Jared DeCoste, a researcher with the US army, about the research team's work to counter the effect of mustard gas. First, the researchers alter E. coli’s DNA to produce an abundance of the molecule protoporphyrin IX. They then mix the protoporphyrin IX with another type of molecule called a metal-organic framework, which then behaves like an absorbent microscopic sponge that detoxifies sulfur mustard, or mustard gas. Read the abstract in MRS Communications (doi: 10.1557/mrc.2019.22).TranscriptSOPHIA CHEN: Today we’re talking about new research out of the military on sulfur mustard, or as it’s more commonly known: mustard gas. Researchers are wondering, could you make some sort of clothing protection for a soldier that basically neutralizes the chemical upon contact? Jared DeCoste is a researcher with the US Army developing these smart uniforms. JARED DECOSTE: We’re doing a lot of research in this area, and we’re excited about the way it’s progressing, and hope to really see these materials being used, at least, in military garments in the coming years. SC: They’re working to develop a weaveable material containing the mustard-neutralizing molecules. But one of the molecules is extremely difficult to make from scratch. It’s called protoporphyrin IX. JD: It’s not a very symmetrical molecule. That means we can’t selectively make the functional groups and so forth to make that molecule. SC: So they needed a different strategy. Fortunately for them, protoporphyrin IX actually occurs a lot in nature. JD: Protoporphyrin IX is actually a precursor to heme, which is in our cells for absorbing oxygen, and a precursor for chlorophyll, which is used by plants to absorb light. SC: And it turns out that E. coli cells make protoporphyrin IX in trace amounts. So DeCoste and his team actually went into the E. coli’s DNA and altered it so that the bacteria would produce it in much larger quantities. Then, they mixed the protoporphyrin IX with another type of molecule called a metal-organic framework. These molecules basically act like absorbent microscopic sponges that other molecules like to stick to. JD: In a typical solid, the only thing to be exposed to be reacted with is the surface. Inherently if you have a sponge or large porous material, everything is a surface. Everything inside your metal-organic framework is readily available to any application you need, be it detoxification, detection, adsorption. SC: This sponge-protoporphyrin hybrid collectively is really good at detoxifying mustard gas. So far, DeCoste’s team is working with the material in powder form, but they’re also trying to figure out how to make it into fibers that can be weaved. But the work isn’t just about this one application to mustard gas, says DeCoste. It’s a demonstration of how genetically engineered cells can produce molecules that are difficult to make using conventional chemistry processes. This material would not have been possible without the modified E. coli. DeCoste thinks that this whole field, synthetic biology, has a lot of potential to benefit materials science. JD: The army and the military in general has a bunch of programs looking at ways to exploiting synthetic biology in general for new materials, making new molecules, and things along those lines. There’s a heavy investment in this area, and it’s a really hot topic right now that’s really started to come into its own. CHEN: This work was published in a recent issue of MRS Communications.

Uber filed to go public this week. No big surprise there; everyone in the industry has been waiting months for the ride-hailing giant to hit the accelerator on its IPO. What did raise an eyebrow were the details the company divulged in its filing—from how it views the future of its business to what it considers its primary challenges in the marketplace. This week, we invite WIRED transportation reporter Aarian Marshall back onto the show to break down all of the revelations in Uber’s S1 filing. You can read her news story about the upcoming Uber IPO right here on WIRED. Also on this week’s pod, Mike, Lauren, and Arielle discuss the first photo of a black hole, the latest privacy concerns around Alexa devices, and some upcoming changes to Facebook’s News Feed. Show notes: Read Aarian on Uber. Read Lily Hay Newman on Alexa, Sophia Chen on the black hole pic, and Emily Dreyfuss and Issie Lapowsky on Facebook. Recommendations this week are Jumbo Privacy Assistant, 1bike1world, and the Criterion Channel. Send the Gadget Lab hosts feedback on their personal Twitter feeds. Arielle Pardes can be found at @pardesoteric. Lauren Goode is @laurengoode. Michael Calore can be found at @snackfight. Our guest Aarian Marshall is @aarianmarshall. Bling the main hotline at @GadgetLab. Our theme song is by Solar Keys. Learn more about your ad choices. Visit megaphone.fm/adchoices

Two of the world's most famous research chimpanzees have finally retired. Hercules and Leo arrived at a chimp sanctuary in Georgia last week. Sarah Crespi checks in with Online News Editor David Grimm on the increasing momentum for research chimp retirement since the primates were labeled endangered species in 2015. Sarah also interviews freelancer Sophia Chen about her piece on x-ray ghost imaging—a technique that may lead to safer medical imaging done with cheap, single-pixel cameras. David Malakoff joins Sarah to talk about the big boost in U.S. science funding signed into law over the weekend. Finally, Jen Golbeck interviews author Stephanie Elizabeth Mohr on her book First in Fly: Drosophila Research and Biological Discovery for our monthly books segment. This week's episode was edited by Podigy. Listen to previous podcasts. [Image: Crystal Alba/Project Chimps; Music: Jeffrey Cook]

Two of the world’s most famous research chimpanzees have finally retired. Hercules and Leo arrived at a chimp sanctuary in Georgia last week. Sarah Crespi checks in with Online News Editor David Grimm on the increasing momentum for research chimp retirement since the primates were labeled endangered species in 2015. Sarah also interviews freelancer Sophia Chen about her piece on x-ray ghost imaging—a technique that may lead to safer medical imaging done with cheap, single-pixel cameras. David Malakoff joins Sarah to talk about the big boost in U.S. science funding signed into law over the weekend. Finally, Jen Golbeck interviews author Stephanie Elizabeth Mohr on her book First in Fly: Drosophila Research and Biological Discovery for our monthly books segment. This week’s episode was edited by Podigy. Listen to previous podcasts. [Image: Crystal Alba/Project Chimps; Music: Jeffrey Cook]