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  • richardmitnick 11:52 am on September 5, 2019 Permalink | Reply
    Tags: "Rice reactor turns greenhouse gas into pure liquid fuel", A common greenhouse gas could be repurposed in an efficient and environmentally friendly way with an electrolyzer that uses renewable electricity to produce pure liquid fuels., , “X-ray absorption spectroscopyenables us to probe the electronic structure of electrocatalysts in operando — that is during the actual chemical process.", , , Formic acid is an energy carrier. It’s a fuel-cell fuel that can generate electricity and emit carbon dioxide — which you can grab and recycle again., Formic acid produced by traditional carbon dioxide devices needs costly and energy-intensive purification steps Wang said., https://www.nature.com/articles/s41560-019-0451-x, In its latest prototype produces highly purified and high concentrations of formic acid., , Rice University, The catalytic reactor developed by the Rice University lab of chemical and biomolecular engineer Haotian Wang uses carbon dioxide as its feedstock., The direct production of pure formic acid solutions will help to promote commercial carbon dioxide conversion technologies., The first was his development of a robust two-dimensional bismuth catalyst and the second a solid-state electrolyte that eliminates the need for salt as part of the reaction., The method is detailed in Nature Energy, The Rice lab worked with Brookhaven National Laboratory to view the process in progress., Two advances made the new device possible said lead author and Rice postdoctoral researcher Chuan Xia.   

    From Rice University: “Rice reactor turns greenhouse gas into pure liquid fuel” 

    Rice U bloc

    From Rice University

    September 3, 2019
    Mike Williams
    713-348-6728
    mikewilliams@rice.edu

    Lab’s ‘green’ invention reduces carbon dioxide into valuable fuels.

    1
    Rice postdoctoral researcher Chuan Xia, left, and chemical and biomolecular engineer Haotian Wang adjust their electrocatalysis reactor to produce liquid formic acid from carbon dioxide. Photo by Jeff Fitlow

    A common greenhouse gas could be repurposed in an efficient and environmentally friendly way with an electrolyzer that uses renewable electricity to produce pure liquid fuels.

    The catalytic reactor developed by the Rice University lab of chemical and biomolecular engineer Haotian Wang uses carbon dioxide as its feedstock and, in its latest prototype, produces highly purified and high concentrations of formic acid.

    Formic acid produced by traditional carbon dioxide devices needs costly and energy-intensive purification steps, Wang said. The direct production of pure formic acid solutions will help to promote commercial carbon dioxide conversion technologies.

    The method is detailed in Nature Energy.

    Wang, who joined Rice’s Brown School of Engineering in January, and his group pursue technologies that turn greenhouse gases into useful products. In tests, the new electrocatalyst reached an energy conversion efficiency of about 42%. That means nearly half of the electrical energy can be stored in formic acid as liquid fuel.

    “Formic acid is an energy carrier,” Wang said. “It’s a fuel-cell fuel that can generate electricity and emit carbon dioxide — which you can grab and recycle again.

    “It’s also fundamental in the chemical engineering industry as a feedstock for other chemicals, and a storage material for hydrogen that can hold nearly 1,000 times the energy of the same volume of hydrogen gas, which is difficult to compress,” he said. “That’s currently a big challenge for hydrogen fuel-cell cars.”

    2
    This schematic shows the electrolyzer developed at Rice to reduce carbon dioxide, a greenhouse gas, to valuable fuels. At left is a catalyst that selects for carbon dioxide and reduces it to a negatively charged formate, which is pulled through a gas diffusion layer (GDL) and the anion exchange membrane (AEM) into the central electrolyte. At the right, an oxygen evolution reaction (OER) catalyst generates positive protons from water and sends them through the cation exchange membrane (CEM). The ions recombine into formic acid or other products that are carried out of the system by deionized (DI) water and gas. Illustration by Chuan Xia and Demin Liu.

    Two advances made the new device possible, said lead author and Rice postdoctoral researcher Chuan Xia. The first was his development of a robust, two-dimensional bismuth catalyst and the second a solid-state electrolyte that eliminates the need for salt as part of the reaction.

    “Bismuth is a very heavy atom, compared to transition metals like copper, iron or cobalt,” Wang said. “Its mobility is much lower, particularly under reaction conditions. So that stabilizes the catalyst.” He noted the reactor is structured to keep water from contacting the catalyst, which also helps preserve it.

    Xia can make the nanomaterials in bulk. “Currently, people produce catalysts on the milligram or gram scales,” he said. “We developed a way to produce them at the kilogram scale. That will make our process easier to scale up for industry.”

    3
    Rice postdoctoral researcher Chuan Xia, left, and chemical and biomolecular engineer Haotian Wang. Photo by Jeff Fitlow

    The polymer-based solid electrolyte is coated with sulfonic acid ligands to conduct positive charge or amino functional groups to conduct negative ions. “Usually people reduce carbon dioxide in a traditional liquid electrolyte like salty water,” Wang said. “You want the electricity to be conducted, but pure water electrolyte is too resistant. You need to add salts like sodium chloride or potassium bicarbonate so that ions can move freely in water.

    “But when you generate formic acid that way, it mixes with the salts,” he said. “For a majority of applications you have to remove the salts from the end product, which takes a lot of energy and cost. So we employed solid electrolytes that conduct protons and can be made of insoluble polymers or inorganic compounds, eliminating the need for salts.”

    The rate at which water flows through the product chamber determines the concentration of the solution. Slow throughput with the current setup produces a solution that is nearly 30% formic acid by weight, while faster flows allow the concentration to be customized. The researchers expect to achieve higher concentrations from next-generation reactors that accept gas flow to bring out pure formic acid vapors.

    The Rice lab worked with Brookhaven National Laboratory to view the process in progress. “X-ray absorption spectroscopy, a powerful technique available at the Inner Shell Spectroscopy (ISS) beamline at Brookhaven Lab’s National Synchrotron Light Source II, enables us to probe the electronic structure of electrocatalysts in operando — that is, during the actual chemical process,” said co-author Eli Stavitski, lead beamline scientist at ISS. “In this work, we followed bismuth’s oxidation states at different potentials and were able to identify the catalyst’s active state during carbon dioxide reduction.”


    BNL NSLS II

    With its current reactor, the lab generated formic acid continuously for 100 hours with negligible degradation of the reactor’s components, including the nanoscale catalysts. Wang suggested the reactor could be easily retooled to produce such higher-value products as acetic acid, ethanol or propanol fuels.

    4
    An electrocatalysis reactor built at Rice recycles carbon dioxide to produce pure liquid fuel solutions using electricity. The scientists behind the invention hope it will become an efficient and profitable way to reuse the greenhouse gas and keep it out of the atmosphere. Photo by Jeff Fitlow

    “The big picture is that carbon dioxide reduction is very important for its effect on global warming as well as for green chemical synthesis,” Wang said. “If the electricity comes from renewable sources like the sun or wind, we can create a loop that turns carbon dioxide into something important without emitting more of it.”

    Co-authors are Rice graduate student Peng Zhu; graduate student Qiu Jiang and Husam Alshareef, a professor of material science and engineering, at King Abdullah University of Science and Technology, Saudi Arabia (KAUST); postdoctoral researcher Ying Pan of Harvard University; and staff scientist Wentao Liang of Northeastern University. Wang is the William Marsh Rice Trustee Assistant Professor of Chemical and Biomolecular Engineering. Xia is a J. Evans Attwell-Welch Postdoctoral Fellow at Rice.

    Rice and the U.S. Department of Energy Office of Science User Facilities supported the research.

    5
    Eli Stavitski, lead scientist at the Inner Shell Spectroscopy (ISS) beamline at Brookhaven National Laboratory’s National Synchrotron Light Source II, used the powerful tool to probe bismuth’s oxidation states, part of the process developed at Rice University to recycle carbon dioxide to produce pure liquid fuel solutions using electricity. (Credit: Brookhaven National Laboratory)

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 12:53 pm on August 31, 2019 Permalink | Reply
    Tags: "The ‘universal break-up criterion’ of hot flowing lava", , Lava fountains at Kilauea in Hawaii created a spatter cone which was estimated to be 180 feet tall., Low-viscosity lava is the red-hot flowing type one might see at Hawaii’s famed Kilauea volcano., Rice University, Tool lets scientists examine changing behavior of low-viscosity lava.,   

    From Rice University: “The ‘universal break-up criterion’ of hot, flowing lava” 

    Rice U bloc

    From Rice University

    August 30, 2019
    Jade Boyd

    Tool lets scientists examine changing behavior of low-viscosity lava.

    1
    Thomas Jones is a Rice Academy Postdoctoral Fellow in Rice University’s Department of Earth, Environmental and Planetary Sciences. (Photo courtesy of T. Jones)

    Thomas Jones’ “universal break-up criterion” won’t help with meltdowns of the heart, but it will help volcanologists study changing lava conditions in common volcanic eruptions.

    Jones, of Rice University, studies the behavior of low-viscosity lava, the runny kind that’s found at most volcanoes. About two years ago, he began a series of lab experiments and field observations that provided the raw inputs for a new fluid dynamic model of lava break-up. The work is described in a paper in Nature Communications.

    Low-viscosity lava is the red-hot, flowing type one might see at Hawaii’s famed Kilauea volcano, and Jones said it usually behaves in one of two ways.

    3
    Lava fountains at Kilauea in Hawaii created a spatter cone, which was estimated to be 180 feet tall in this June 2018 photo. (Image courtesy of U.S. Geological Survey)

    “It can bubble or spew out, breaking into chunks that spatter about the vent, or it can flow smoothly, forming lava streams that can rapidly move downhill,” he said.

    But that behavior can sometimes change quickly during the course of an eruption, and so can the associated dangers: While spattering eruptions throw hot lava fragments into the air, lava flows can threaten to destroy whole neighborhoods and towns.

    Jones’ model, the first of its kind, allows scientists to calculate when an eruption will transition from a spattering spray to a flowing stream, based upon the liquid properties of the lava itself and the eruption conditions at the vent.

    Jones said additional work is needed to refine the tool, and he looks forward to doing some of it himself.

    “We will validate this by going to an active volcano, taking some high-speed videos and seeing when things break apart and under what conditions,” he said. “We also plan to look at the effect of adding bubbles and crystals, because real magmas aren’t as simple as the idealized liquid in our mathematical model. Real magmas can also have bubbles and crystals in them. I’m sure those will change things. We want to find out how.”

    Jones said pairing the new model with real-time information about a lava’s liquid properties and eruption conditions could allow emergency officials to predict when an eruption will change style and become a hazard to at-risk communities.

    4
    Lava from a fountain on Hawaii’s Kilauea volcano flows over a spillway into an established channel in June 2018. (Image courtesy of U.S. Geological Survey)

    “We want to use this as a forecasting tool for eruption behavior,” he said. “By developing a model of what’s happening in the subsurface we can then watch for indications that it’s about to cross the tipping point and change behavior.”

    The study was co-authored by C.D. Reynolds of the University of Birmingham in the United Kingdom and S.C. Boothroyd of Durham University, also in the UK. The research was supported by the UK’s National Environment Research Council and Rice University.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 11:00 am on August 1, 2019 Permalink | Reply
    Tags: "Oddball edge wins nanotube faceoff", A zigzag nanotube’s end looks like a saw tooth while an armchair is like a row of seats with armrests., , , , Rice University, The two-faced “Janus” configuration   

    From Rice University: “Oddball edge wins nanotube faceoff” 

    Rice U bloc

    From Rice University

    July 29, 2019
    Mike Williams

    Rice theory shows peculiar ‘Janus’ interface a common mechanism in carbon nanotube growth.

    When is a circle less stable than a jagged loop? Apparently when you’re talking about carbon nanotubes.

    Rice University theoretical researchers have discovered that nanotubes with segregated sections of “zigzag” and “armchair” facets growing from a solid catalyst are far more energetically stable than a circular arrangement would be.

    2
    Rice University researchers have determined that an odd, two-faced “Janus” edge is more common than previously thought for carbon nanotubes growing on a rigid catalyst. The conventional nanotube at left has facets that form a circle, allowing the nanotube to grow straight up from the catalyst. But they discovered the nanotube at right, with a tilted Janus edge that has segregated sections of zigzag and armchair configurations, is far more energetically favored when growing carbon nanotubes via chemical vapor deposition. Illustration by Evgeni Penev.

    Under the right circumstances, they reported, the interface between a growing nanotube and its catalyst can reach its lowest-known energy state via the two-faced “Janus” configuration, with a half-circle of zigzags opposite six armchairs.

    The terms refer to the shape of the nanotube’s edge: A zigzag nanotube’s end looks like a saw tooth, while an armchair is like a row of seats with armrests. They are the basic edge configurations of the two-dimensional honeycomb of carbon atoms known as graphene (as well as other 2D materials) and determine many of the materials’ properties, especially electrical conductivity.

    The Brown School of Engineering team of materials theorist Boris Yakobson, researcher and lead author Ksenia Bets and assistant research professor Evgeni Penev reported their results in the American Chemical Society journal ACS Nano.

    The theory is a continuation of the team’s discovery last year that Janus interfaces are likely to form on a catalyst of tungsten and cobalt, leading to a single chirality, called (12,6), that other labs had reported growing in 2014.

    The Rice team now shows such structures aren’t unique to a specific catalyst, but are a general characteristic of a number of rigid catalysts. That’s because the atoms attaching themselves to the nanotube edge always seek their lowest energy states, and happen to find it in the Janus configuration they named A|Z.

    “People have assumed in studies that the geometry of the edge is a circle,” Penev said. “That’s intuitive — it’s normal to assume that the shortest edge is the best. But we found for chiral tubes the slightly elongated Janus edge allows it to be in much better contact with solid catalysts. The energy for this edge can be quite low.”

    In the circle configuration, the flat armchair bottoms rest on the substrate, providing the maximum number of contacts between the catalyst and the nanotube, which grows straight up. (Janus edges force them to grow at an angle.)

    Carbon nanotubes — long, rolled-up tubes of graphene — are difficult enough to see with an electron microscope. As yet there’s no way to observe the base of a nanotube as it grows from the bottom up in a chemical vapor deposition furnace. But theoretical calculations of the atom-level energy that passes between the catalyst and the nanotube at the interface can tell researchers a lot about how they grow.

    That’s a path the Rice lab has pursued for more than a decade, pulling at the thread that reveals how minute adjustments in nanotube growth can change the kinetics, and ultimately how nanotubes can be used in applications.

    “Generally, the insertion of new atoms at the nanotube edge requires breaking the interface between the nanotube and the substrate,” Bets said. “If the interface is tight, it would cost too much energy. That is why the screw dislocation growth theory proposed by Professor Yakobson in 2009 was able to connect the growth rate with the presence of kinks, the sites on the nanotube edge that disrupt the tight carbon nanotube-substrate contact.

    “Curiously, even though Janus edge configuration allows very tight contact with the substrate it still preserves a single kink that would allow continuous nanotube growth, as we demonstrated last year for the cobalt tungsten catalyst,” Bets said.

    Bets ran extensive computer simulations to model nanotubes growing on three rigid catalysts that showed evidence of Janus growth and one more “fluid” catalyst, tungsten carbide, that did not. “The surface of that catalyst is very mobile, so the atoms can move a lot,” Penev said. “For that one, we did not observe a clear segregation.”

    Yakobson compared Janus nanotubes to the Wulff shape of crystals. “It’s somewhat surprising that our analysis suggests a restructured, faceted edge is energetically favored for chiral tubes,” he said. “Assuming that the lowest energy edge must be a minimal-length circle is like assuming that a crystal shape must be a minimal-surface sphere but we know well that 3D shapes have facets and 2D shapes are polygons, as epitomized by the Wulff construction.

    “Graphene has by necessity several ‘sides,’ but a nanotube cylinder has one rim, making the energy analysis different,” he said. “This raises fundamentally interesting and practically important questions about the relevant structure of the nanotube edges.”

    The Rice researchers hope their discovery will advance them along the path toward those answers. “The immediate implication of this finding is a paradigm shift in our understanding of growth mechanisms,” Yakobson said. “That may become important in how one practically designs the catalyst for efficient growth, especially of controlled nanotube symmetry type, for electronic and optical utility.”

    Yakobson is the Karl F. Hasselmann Professor of Materials Science and NanoEngineering and of Chemistry. The National Science Foundation (NSF) and the Air Force Office of Scientific Research supported the research.

    Computing resources were provided by the Department of Defense Supercomputing Resource Center; the National Energy Research Scientific Computing Center, supported by the Department of Energy Office of Science; the NSF-supported XSEDE supercomputer; and the NSF-supported DAVinCI cluster at Rice, administered by the Center for Research Computing and procured in partnership with Rice’s Ken Kennedy Institute for Information Technology.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 9:14 am on June 4, 2019 Permalink | Reply
    Tags: "For The First Time Physicists Have Produced a Stunning Type of Plasma Jet in The Lab", , , Rice University   

    From Rice University via From Science Alert: “For The First Time, Physicists Have Produced a Stunning Type of Plasma Jet in The Lab” 

    Rice U bloc

    From Rice University

    via

    ScienceAlert

    From Science Alert

    4 JUN 2019
    DAVID NIELD

    1
    OMEGA laser. (Rather Anonymous/Flickr/CC BY NC 2.0)

    Plasma, that super-hot mix of electrified atomic particles, plays a key role in the evolution of stars, black holes, and other cosmic elements. For closer study though, plasma needs to be recreated in a lab – and researchers have just managed to generate a particular type of plasma jet for the first time.

    The key characteristics of this lab-created plasma jet are its stability and its magnetism. Further study of the jet could help us unlock some more of the secrets of the Universe.

    Not only that, the scientists were able to run some advanced diagnostics on the jet – getting readings for its density, temperature, length, coherence, and magnetic field – which helps them better compare it to plasma out in space.

    “We are now creating stable, supersonic, and strongly magnetised plasma jets in a laboratory that might allow us to study astrophysical objects light years away,” says one of the team leaders, astrophysicist Edison Liang from Rice University in Texas.

    The researchers trained 20 individual laser beams into a circular shape on a plastic target to produce puffs of plasma, which were then pressurised as they expanded to create a plasma jet four millimetres (0.16 inches) in length, with a magnetic field strength of over 100 tesla (about 10,000 times stronger than a small bar magnet).

    Those original laser beams weren’t any ordinary lights, though – they were produced by the OMEGA laser at the Laboratory for Laser Energetics, part of the University of Rochester in New York. It’s one of the most powerful lasers in the world, capable of focussing huge energy bursts on very small targets.

    U Rochester OMEGA EP Laser System


    U Rochester Omega Laser

    Thanks to the diagnostic work the researchers carried out on the plasma jet, they now have a baseline to use to see how the plasma reacts under different conditions.

    Future tests will involve different types of plasma-related phenomena, such as using an external magnetic field to see if the jet grows in size and becomes more collimated (with parallel rays).

    The researchers also want to try the same experiment with the National Ignition Facility at Lawrence Livermore National Laboratory, which has no fewer than 192 laser beams – half of those could contribute to the plasma laser ring.

    “It would have a larger radius and thus produce a longer jet than that produced using OMEGA,” says one of the lead researchers, physicist Lan Gao from the Princeton Plasma Physics Laboratory (PPPL). “This process would help us figure out under which conditions the plasma jet is strongest.”

    The circle method the researchers developed here has the potential to scale up very well, the researchers say, and is similar to the plasma offshoots that might be observed from a newborn star – only easier to study up close.

    As the research continues, we should learn more about this special state of matter and the role it plays in the wider cosmos (as well as any ordinary microwave, if the right conditions are met).

    “This is groundbreaking research because no other team has successfully launched a supersonic, narrowly beamed jet that carries such a strong magnetic field, extending to significant distances,” says Liang.

    “This is the first time that scientists have demonstrated that the magnetic field does not just wrap around the jet, but also extends parallel to the jet’s axis.”

    The research has been published in The Astrophysical Journal Letters.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 11:55 am on May 6, 2019 Permalink | Reply
    Tags: "Organ bioprinting gets a breath of fresh air", 3D printing replacement organs, , , , Rice University,   

    From Rice University and UW Medicine: “Organ bioprinting gets a breath of fresh air” 

    U Washington
    University of Washington

    UW Medicine Newsroom

    Rice U bloc

    From Rice University

    May 2, 2019
    David Ruth
    713-348-6327
    david@rice.edu

    Jade Boyd
    713-348-6778
    jadeboyd@rice.edu

    Bioengineers clear major hurdle on path to 3D printing replacement organs.

    Bioengineers have cleared a major hurdle on the path to 3D printing replacement organs with a breakthrough technique for bioprinting tissues.

    1
    The May 3 issue of Science features a breakthrough bioprinting technique developed by Rice University bioengineer Jordan Miller and colleagues. (Reprinted with permission from AAAS. Photo by Dan Sazer, Jeff Fitlow and Jordan Miller/Rice University)

    The new innovation allows scientists to create exquisitely entangled vascular networks that mimic the body’s natural passageways for blood, air, lymph and other vital fluids.

    The research is featured on the cover of this week’s issue of Science. It includes a visually stunning proof-of-principle — a hydrogel model of a lung-mimicking air sac in which airways deliver oxygen to surrounding blood vessels. Also reported are experiments to implant bioprinted constructs containing liver cells into mice.

    The work was led by bioengineers Jordan Miller of Rice University and Kelly Stevens of the University of Washington (UW) and included 15 collaborators from Rice, UW, Duke University, Rowan University and Nervous System, a design firm in Somerville, Massachusetts.

    “One of the biggest road blocks to generating functional tissue replacements has been our inability to print the complex vasculature that can supply nutrients to densely populated tissues,” said Miller, assistant professor of bioengineering at Rice’s Brown School of Engineering. “Further, our organs actually contain independent vascular networks — like the airways and blood vessels of the lung or the bile ducts and blood vessels in the liver. These interpenetrating networks are physically and biochemically entangled, and the architecture itself is intimately related to tissue function. Ours is the first bioprinting technology that addresses the challenge of multivascularization in a direct and comprehensive way.”

    Stevens, assistant professor of bioengineering in the UW College of Engineering, assistant professor of pathology in the UW School of Medicine, and an investigator at the UW Medicine Institute for Stem Cell and Regenerative Medicine, said multivascularization is important because form and function often go hand in hand.

    3
    Rice University bioengineering graduate student Bagrat Grigoryan led the development of a new technique for 3D printing tissue with entangled vascular networks similar to the body’s natural passageways for blood, air and other vital fluids. (Photo by Jeff Fitlow/Rice University)

    “Tissue engineering has struggled with this for a generation,” Stevens said. “With this work we can now better ask, ‘If we can print tissues that look and now even breathe more like the healthy tissues in our bodies, will they also then functionally behave more like those tissues?’ This is an important question, because how well a bioprinted tissue functions will affect how successful it will be as a therapy.”

    The goal of bioprinting healthy, functional organs is driven by the need for organ transplants. More than 100,000 people are on transplant waiting lists in the United States alone, and those who do eventually receive donor organs still face a lifetime of immune-suppressing drugs to prevent organ rejection. Bioprinting has attracted intense interest over the past decade because it could theoretically address both problems by allowing doctors to print replacement organs from a patient’s own cells. A ready supply of functional organs could one day be deployed to treat millions of patients worldwide.

    “We envision bioprinting becoming a major component of medicine within the next two decades,” Miller said.

    4
    Rice University bioengineers (from left) Bagrat Grigoryan, Jordan Miller and Daniel Sazer and collaborators created a breakthrough bioprinting technique that could speed development of technology for 3D printing replacement organs and tissues. (Photo by Jeff Fitlow/Rice University)

    “The liver is especially interesting because it performs a mind-boggling 500 functions, likely second only to the brain,” Stevens said. “The liver’s complexity means there is currently no machine or therapy that can replace all its functions when it fails. Bioprinted human organs might someday supply that therapy.”

    To address this challenge, the team created a new open-source bioprinting technology dubbed the “stereolithography apparatus for tissue engineering,” or SLATE. The system uses additive manufacturing to make soft hydrogels one layer at a time.

    Layers are printed from a liquid pre-hydrogel solution that becomes a solid when exposed to blue light. A digital light processing projector shines light from below, displaying sequential 2D slices of the structure at high resolution, with pixel sizes ranging from 10-50 microns. With each layer solidified in turn, an overhead arm raises the growing 3D gel just enough to expose liquid to the next image from the projector. The key insight by Miller and Bagrat Grigoryan, a Rice graduate student and lead co-author of the study, was the addition of food dyes that absorb blue light. These photoabsorbers confine the solidification to a very fine layer. In this way, the system can produce soft, water-based, biocompatible gels with intricate internal architecture in a matter of minutes.

    5
    Rice University bioengineer Daniel Sazer prepares a scale-model of a lung-mimicking air sac for testing. In experiments, air is pumped into the sac in a pattern that mimics breathing while blood is flowed through a surrounding network of blood vessels to oxygenate human red blood cells. (Photo by Jeff Fitlow/Rice University)

    Tests of the lung-mimicking structure showed that the tissues were sturdy enough to avoid bursting during blood flow and pulsatile “breathing,” a rhythmic intake and outflow of air that simulated the pressures and frequencies of human breathing. Tests found that red blood cells could take up oxygen as they flowed through a network of blood vessels surrounding the “breathing” air sac. This movement of oxygen is similar to the gas exchange that occurs in the lung’s alveolar air sacs.

    To design the study’s most complicated lung-mimicking structure, which is featured on the cover of Science, Miller collaborated with study co-authors Jessica Rosenkrantz and Jesse Louis-Rosenberg, co-founders of Nervous System.

    “When we founded Nervous System it was with the goal of adapting algorithms from nature into new ways to design products,” Rosenkrantz said. “We never imagined we’d have the opportunity to bring that back and design living tissues.”

    6
    Experiments performed by Rice University and University of Washington researchers explored whether liver cells called hepatocytes would function normally if they were incorporated into a bioprinted implant and surgically implanted in mice for 14 days. (Image courtesy of Jordan Miller/Rice University)

    In the tests of therapeutic implants for liver disease, the team 3D printed tissues, loaded them with primary liver cells and implanted them into mice. The tissues had separate compartments for blood vessels and liver cells and were implanted in mice with chronic liver injury. Tests showed that the liver cells survived the implantation.

    Miller said the new bioprinting system can also produce intravascular features, like bicuspid valves that allow fluid to flow in only one direction. In humans, intravascular valves are found in the heart, leg veins and complementary networks like the lymphatic system that have no pump to drive flow.

    “With the addition of multivascular and intravascular structure, we’re introducing an extensive set of design freedoms for engineering living tissue,” Miller said. “We now have the freedom to build many of the intricate structures found in the body.”

    Miller and Grigoryan are commercializing key aspects of the research through a Houston-based startup company called Volumetric. The company, which Grigoryan has joined full time, is designing and manufacturing bioprinters and bioinks.

    7
    Assistant professor Kelly Stevens (left) and graduate student Daniel Corbett (right) from the University of Washington Departments of Bioengineering and Pathology helped develop a new method to bioprint liver tissue. (Photo by Dennis R. Wise/University of Washington)

    Miller, a longstanding champion of open-source 3D printing, said all source data from the experiments in the published Science study are freely available [see the Science paper above]. In addition, all 3D printable files needed to build the stereolithography printing apparatus are available, as are the design files for printing each of the hydrogels used in the study.

    See the full Rice university article here .
    See the full U Washington Medicine article here .


    five-ways-keep-your-child-safe-school-shootings

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

    About UW Medicine

    UW Medicine is one of the top-rated academic medical systems in the world. With a mission to improve the health of the public, UW Medicine educates the next generation of physicians and scientists, leads one of the world’s largest and most comprehensive biomedical research programs, and provides outstanding care to patients from across the globe.

    The UW School of Medicine, part of the UW Medicine system, leads the internationally recognized, community-based WWAMI Program, serving the states of Washington, Wyoming, Alaska, Montana and Idaho. The school has been ranked No. 1 in the nation in primary-care training for more than 20 years by U.S. News & World Report. It is also second in the nation in federal research grants and contracts with $749.9 million in total revenue (fiscal year 2016) according to the Association of American Medical Colleges.

    UW Medicine has more than 27,000 employees and an annual budget of nearly $5 billion. Also part of the UW Medicine system are Airlift Northwest and the UW Physicians practice group, the largest physician practice plan in the region. UW Medicine shares in the ownership and governance of the Seattle Cancer Care Alliance with Fred Hutchinson Cancer Research Center and Seattle Children’s, and also shares in ownership of Children’s University Medical Group with Seattle Children’s.

    u-washington-campus
    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
    So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 2:05 pm on February 18, 2019 Permalink | Reply
    Tags: "Can we trust scientific discoveries made using machine learning?", , , Machine learning (ML) is a branch of statistics and computer science concerned with building computational systems that learn from data rather than following explicit instructions, Rice University   

    From Rice University: “Can we trust scientific discoveries made using machine learning?” 

    Rice U bloc

    From Rice University

    February 18, 2019

    Jeff Falk
    713-348-6775
    jfalk@rice.edu

    Jade Boyd
    713-348-6778
    jadeboyd@rice.edu

    Rice U. expert: Key is creating ML systems that question their own predictions.

    Rice University statistician Genevera Allen says scientists must keep questioning the accuracy and reproducibility of scientific discoveries made by machine-learning techniques until researchers develop new computational systems that can critique themselves.

    1
    Genevera Allen (Photo by Tommy LaVergne/Rice University)

    Allen, associate professor of statistics, computer science and electrical and computer engineering at Rice and of pediatrics-neurology at Baylor College of Medicine, will address the topic in both a press briefing and a general session today at the 2019 Annual Meeting of the American Association for the Advancement of Science (AAAS).

    “The question is, ‘Can we really trust the discoveries that are currently being made using machine-learning techniques applied to large data sets?’” Allen said. “The answer in many situations is probably, ‘Not without checking,’ but work is underway on next-generation machine-learning systems that will assess the uncertainty and reproducibility of their predictions.”

    Machine learning (ML) is a branch of statistics and computer science concerned with building computational systems that learn from data rather than following explicit instructions. Allen said much attention in the ML field has focused on developing predictive models that allow ML to make predictions about future data based on its understanding of data it has studied.

    “A lot of these techniques are designed to always make a prediction,” she said. “They never come back with ‘I don’t know,’ or ‘I didn’t discover anything,’ because they aren’t made to.”

    She said uncorroborated data-driven discoveries from recently published ML studies of cancer data are a good example.

    “In precision medicine, it’s important to find groups of patients that have genomically similar profiles so you can develop drug therapies that are targeted to the specific genome for their disease,” Allen said. “People have applied machine learning to genomic data from clinical cohorts to find groups, or clusters, of patients with similar genomic profiles.

    “But there are cases where discoveries aren’t reproducible; the clusters discovered in one study are completely different than the clusters found in another,” she said. “Why? Because most machine-learning techniques today always say, ‘I found a group.’ Sometimes, it would be far more useful if they said, ‘I think some of these are really grouped together, but I’m uncertain about these others.’”

    Allen will discuss uncertainty and reproducibility of ML techniques for data-driven discoveries at a 10 a.m. press briefing today, and she will discuss case studies and research aimed at addressing uncertainty and reproducibility in the 3:30 p.m. general session, “Machine Learning and Statistics: Applications in Genomics and Computer Vision.” Both sessions are at the Marriott Wardman Park Hotel.

    Allen is the founding director of Rice’s Center for Transforming Data to Knowledge (D2K Lab) and a member of the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital. Her research lies in the areas of modern multivariate analysis, graphical models, statistical machine learning and data integration, with a particular focus on statistical methods that help scientists make sense of “big data” from high-throughput genomics, neuroimaging and other applications. Her previous honors include a National Science Foundation CAREER award, the International Biometric Society’s Young Statistician Showcase award and Forbes ’30 under 30′ in science and health care.

    AAAS is the world’s largest multi-disciplinary science society, and the AAAS Annual Meeting, Feb. 14-17, is the world’s largest general scientific gathering. For more information, visit: https://aaas.org.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 12:58 pm on January 7, 2019 Permalink | Reply
    Tags: , , , , Plasma is an electrically conductive mix of electrons and ions, Rice University, Rice University physicists are first to laser cool neutral plasma, Ultracold simulators of super-dense stars   

    From Rice University: ” Ultracold simulators of super-dense stars” 

    Rice U bloc

    From Rice University

    January 3, 2019
    Jade Boyd

    Rice University physicists are first to laser cool neutral plasma.

    Rice University physicists have created the world’s first laser-cooled neutral plasma, completing a 20-year quest that sets the stage for simulators that re-create exotic states of matter found inside Jupiter and white dwarf stars.

    The findings are detailed this week in the journal Science and involve new techniques for laser cooling clouds of rapidly expanding plasma to temperatures about 50 times colder than deep space.

    “We don’t know the practical payoff yet, but every time physicists have laser cooled a new kind of thing, it has opened a whole world of possibilities,” said lead scientist Tom Killian, professor of physics and astronomy at Rice. “Nobody predicted that laser cooling atoms and ions would lead to the world’s most accurate clocks or breakthroughs in quantum computing. We do this because it’s a frontier.”

    Killian and graduate students Tom Langin and Grant Gorman used 10 lasers of varying wavelengths to create and cool the neutral plasma. They started by vaporizing strontium metal and using one set of intersecting laser beams to trap and cool a puff of strontium atoms about the size of a child’s fingertip. Next, they ionized the ultracold gas with a 10-nanosecond blast from a pulsed laser. By stripping one electron from each atom, the pulse converted the gas to a plasma of ions and electrons.

    1
    Rice University physicists reported the first laser-cooled neutral plasma, a breakthrough that could lead to simulators for exotic states of matter that occur at the center of Jupiter or white dwarf stars. (Photo by Brandon Martin/Rice University)

    Energy from the ionizing blast causes the newly formed plasma to expand rapidly and dissipate in less than one thousandth of a second. This week’s key finding is that the expanding ions can be cooled with another set of lasers after the plasma is created. Killian, Langin and Gorman describe their techniques in the new paper, clearing the way for their lab and others to make even colder plasmas that behave in strange, unexplained ways.

    Plasma is an electrically conductive mix of electrons and ions. It is one of four fundamental states of matter; but unlike solids, liquids and gases, which are familiar in daily life, plasmas tend to occur in very hot places like the surface of the sun or a lightning bolt. By studying ultracold plasmas, Killian’s team hopes to answer fundamental questions about how matter behaves under extreme conditions of high density and low temperature.

    To make its plasmas, the group starts with laser cooling, a method for trapping and slowing particles with intersecting laser beams. The less energy an atom or ion has, the colder it is, and the slower it moves about randomly. Laser cooling was developed in the 1990s to slow atoms until they are almost motionless, or just a few millionths of a degree above absolute zero.

    2
    Rice University graduate student Tom Langin makes an adjustment to an experiment that uses dozens of lasers of varying wavelengths to laser-cool ions in a neutral plasma that is made by first laser-cooling strontium atoms and then ionizing them with a high-power laser. (Photo by Brandon Martin/Rice University)

    “If an atom or ion is moving, and I have a laser beam opposing its motion, as it scatters photons from the beam it gets momentum kicks that slow it,” Killian said. “The trick is to make sure that light is always scattered from a laser that opposes the particle’s motion. If you do that, the particle slows and slows and slows.”

    During a postdoctoral fellowship at the National Institute of Standards and Technology in Bethesda, Md., in 1999, Killian pioneered the ionization method for creating neutral plasma from a laser-cooled gas. When he joined Rice’s faculty the following year, he started a quest for a way to make the plasmas even colder. One motivation was to achieve “strong coupling,” a phenomenon that happens naturally in plasmas only in exotic places like white dwarf stars and the center of Jupiter.

    “We can’t study strongly coupled plasmas in places where they naturally occur,” Killian said. “Laser cooling neutral plasmas allows us to make strongly coupled plasmas in a lab, so that we can study their properties.

    “In strongly coupled plasmas, there is more energy in the electrical interactions between particles than in the kinetic energy of their random motion,” Killian said. “We mostly focus on the ions, which feel each other, and rearrange themselves in response to their neighbors’ positions. That’s what strong coupling means.”

    3
    To laser-cool a neutral plasma, Rice University physicists start by vaporizing billions of strontium atoms, which are laser-cooled and laser-ionized to create a rapidly expanding cloud of neutral ions. Another set of lasers cools the ions. (Photo by Brandon Martin/Rice University)

    Because the ions have positive electric charges, they repel one another through the same force that makes your hair stand up straight if it gets charged with static electricity.

    “Strongly coupled ions can’t be near one another, so they try to find equilibrium, an arrangement where the repulsion from all of their neighbors is balanced,” he said. “This can lead to strange phenomena like liquid or even solid plasmas, which are far outside our normal experience.”

    In normal, weakly coupled plasmas, these repulsive forces only have a small influence on ion motion because they’re far outweighed by the effects of kinetic energy, or heat.

    “Repulsive forces are normally like a whisper at a rock concert,” Killian said. “They’re drowned out by all the kinetic noise in the system.”

    In the center of Jupiter or a white dwarf star, however, intense gravity squeezes ions together so closely that repulsive forces, which grow much stronger at shorter distances, win out. Even though the temperature is quite high, ions become strongly coupled.

    4
    Rice University graduate student Tom Langin at the laser-table where beams of various wavelengths were used to make the world’s first ultracold neutral plasma. (Photo by Brandon Martin/Rice University)

    Killian’s team creates plasmas that are orders of magnitude lower in density than those inside planets or dead stars, but by lowering the temperature they raise the ratio of electric-to-kinetic energies. At temperatures as low as one-tenth of a Kelvin above absolute zero, Killian’s team has seen repulsive forces take over.

    “Laser cooling is well developed in gases of neutral atoms, for example, but the challenges are very different in plasmas,” he said.

    “We are just at the beginning of exploring the implications of strong coupling in ultracold plasmas,” Killian said. “For example, it changes the way that heat and ions diffuse through the plasma. We can study those processes now. I hope this will improve our models of exotic, strongly coupled astrophysical plasmas, but I am sure we will also make discoveries that we haven’t dreamt of yet. This is the way science works.”

    The research was supported by the Air Force Office of Scientific Research and the Department of Energy’s Office of Science.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 10:17 pm on May 29, 2018 Permalink | Reply
    Tags: , New role for asthenosphere in plate movements, , Rice University   

    From Rice University: “Flow in the asthenosphere drags tectonic plates along” 

    Rice U bloc

    From Rice University

    May 29, 2018
    Jade Boyd

    Rice University’s 3D model suggests new role for asthenosphere in plate movements.

    1
    A graphic showing the convective heat cycle (red arrows) that drive plate tectonic motion (black arrows) on Earth. Heat flows toward subduction zones through the uppermost mantle layer, the asthenosphere. A realistic new computer model from Rice University finds that the asthenosphere moves and drags plates along with it rather than acting as a brake on plate movements as had been widely believed. (Image courtesy of Surachit/Wikimedia Commons)

    New simulations of Earth’s asthenosphere find that convective cycling and pressure-driven flow can sometimes cause the planet’s most fluid layer of mantle to move even faster than the tectonic plates that ride atop it.

    That’s one conclusion from a new study by Rice University geophysicists who modeled flow in the 100-mile-thick layer of mantle that begins at the base of Earth’s tectonic plates, or lithosphere.

    The study, in the journal Earth and Planetary Science Letters, takes aim at a much-debated question in geophysics: What drives the movement of Earth’s tectonic plates, the 57 interlocking slabs of the lithosphere that slip, grind and bump against one another in a seismic dance that causes earthquakes, builds continents and gradually reshapes the planet’s surface every few million years?

    The tectonic plates of the world were mapped in 1996, USGS.

    “Tectonic plates float on top of the asthenosphere, and the leading theory for the past 40 years is that the lithosphere moves independently of the asthenosphere, and the asthenosphere only moves because the plates are dragging it along,” said graduate student Alana Semple, lead co-author of the new study. “Detailed observations of the asthenosphere from a Lamont research group returned a more nuanced picture and suggested, among other things, that the asthenosphere has a constant speed at its center but is changing speeds at its top and base, and that it sometimes appears to flow in a different direction than the lithosphere.”

    Computational modeling carried out at Rice offers a theoretical framework that can explain these puzzling observations, said Adrian Lenardic, a study co-author and professor of Earth, environmental and planetary sciences at Rice.

    “We’ve shown how these situations can occur through a combination of plate- and pressure-driven flow in the asthenosphere,” he said. “The key was realizing that a theory developed by former Rice postdoc Tobias Höink had the potential to explain the Lamont observations if a more accurate representation of the asthenosphere’s viscosity was allowed for. Alana’s numerical simulations incorporated that type of viscosity and showed that the modified model could explain the new observations. In the process, this offered a new way of thinking about the relationship between the lithosphere and asthenosphere.”

    Though the asthenosphere is made of rock, it is under intense pressure that can cause its contents to flow.

    “Thermal convection in Earth’s mantle generates dynamic pressure variations,” Semple said. “The weakness of the asthenosphere, relative to tectonic plates above, allows it to respond differently to the pressure variations. Our models show how this can lead to asthenosphere velocities that exceed those of plates above. The models also show how flow in the asthenosphere can be offset from that of plates, in line with the observations from the Lamont group”

    The oceanic lithosphere is formed at mid-ocean ridges and flows toward subduction zones where one tectonic plate slides beneath another. In the process, the lithosphere cools and heat from Earth’s interior is transferred to its surface. Subduction recycles cooler lithospheric material into the mantle, and the cooling currents flow back into the deep interior.

    Semple’s 3D model simulates both this convective cycle and the asthenosphere. She credited Rice’s Center for Research Computing (CRC) for its help running simulations — some of which took as long as six weeks — on Rice’s DAVinCI supercomputer.

    Rice DAVinCI IBM iDataPlex supercomputer

    Semple said the simulations show how convective cycling and pressure-driven flow can drive tectonic movement.

    “Our paper suggests that pressure-driven flow in the asthenosphere can contribute to the motion of tectonic plates by dragging plates along with it,” she said. “A notable contribution does come from ‘slab-pull,’ a gravity-driven process that pulls plates toward subduction zones. Slab-pull can still be the dominant process that moves plates, but our models show that asthenosphere flow provides a more significant contribution to plate movement than previously thought.”

    The research was supported by the National Science Foundation. DAVinCI is administered by CRC and was procured in partnership with Rice’s Ken Kennedy Institute for Information Technology.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 10:16 am on March 2, 2018 Permalink | Reply
    Tags: , , , Rice University, Rydberg polarons   

    From Rice: “Dressing atoms in an ultracold soup” 

    Rice U bloc

    Rice University

    February 28, 2018
    Jade Boyd

    Physicists build bizarre molecules called ‘Rydberg polarons’

    Using lasers, U.S. and Austrian physicists have coaxed ultracold strontium atoms into complex structures unlike any previously seen in nature.

    “I am amazed that we’ve discovered a new way that atoms assemble,” said Rice University physicist Tom Killian. “It shows how rich the laws of physics and chemistry can be.” Killian is the lead scientist on a new paper in Physical Review Letters that summarized the group’s experimental findings.

    Killian teamed with experimental physicists from Rice’s Center for Quantum Materials and theoretical physicists from Harvard University and Vienna University of Technology on the two-year project to create “Rydberg polarons” out of strontium atoms that were at least 1 million times colder than deep space.

    The team’s findings, which are summarized in the PRL paper and a companion theoretical study appearing this week in Physical Review A, reveal something new about the basic nature of matter, Killian said.

    “The basic laws that we learn in chemistry class tell us how atoms bond together to form molecules, and a deep understanding of those principles is what allows chemists and engineers to make the materials we use in our everyday lives,” he said. “But those laws are also quite rigid. Only certain combinations of atoms will form stable bonds in a molecule. Our work explored a new type of molecule that isn’t described by any of the traditional rules for binding atoms together.”

    1
    Rice University physicists (clockwise from left) Soumya Kanungo, Tom Killian, Roger Ding, Barry Dunning and Joe Whalen used lasers and an ultracold strontium gas to make “Rydberg polarons,” complex molecules unlike any previously seen in nature. (Photo by Jeff Fitlow/Rice University)

    Killian said the new molecules are only stable at extraordinarily cold temperatures — about a millionth of a degree above absolute zero. At such low temperatures, the constituent atoms stay still long enough to become “glued together” in new, complex structures, he said.

    “One amazing thing is that you can keep attaching an arbitrary number of atoms to these molecules,” Killian said. “It’s just like attaching Lego blocks, which you can’t do with traditional types of molecules.”

    He said the discovery will be of interest to theoretical chemists, condensed matter physicists, atomic physicists and physicists who are studying Rydberg atoms for potential use in quantum computers.

    “Nature takes advantage of a fascinating toolbox of tricks for binding atoms together to make molecules and materials,” Killian said. “As we discover and understand these tricks, we satisfy our innate curiosity about the world we live in, and it can often lead to practical advances like new therapeutic drugs or light-harvesting solar cells. It is too early to tell if any practical applications will come from our work, but basic research like this is what it takes to find tomorrow’s great breakthroughs.”

    The team’s efforts centered around making, measuring and predicting the behavior of a specific state of matter called a Rydberg polaron, a combination of two distinct phenomena, Rydberg atoms and polarons.

    In Rydberg atoms, one or more electrons are excited with a precise amount of energy so that they orbit far from the atom’s nucleus. Rydberg atoms can be described with simple rules written down more than a century ago by Swedish physicist Johannes Rydberg. They have been studied in laboratories for decades and are believed to exist in cold reaches of deep space. The Rydberg atoms in the PRL study were up to one micron wide, about 1,000 times larger than normal strontium atoms.

    2
    Rice University atomic physicist Joe Whalen works on a laser cooling system for ultracold strontium gas. (Photo by Jeff Fitlow/Rice University)

    Polarons are created when a single particle interacts strongly with its environment and causes nearby electrons, ions or atoms to rearrange themselves and form a sort of coating that the particle carries with it. The polaron itself is a collective — a unified object known as a quasiparticle — that incorporates properties of the original particle and its environment.

    Rydberg polarons are a new class of polarons in which the high-energy, far-orbiting electron gathers hundreds of atoms within its orbit as it moves through a dense, ultracold cloud. In the Rice experiments, researchers began by creating a supercooled cloud of several hundred thousand strontium atoms. By coordinating the timing of laser pulses with changes in the electric field, the researchers were able to create and count Rydberg polarons one by one, ultimately forming millions of them for their study.

    While Rydberg polarons had previously been created with rubidium, the use of strontium allowed the physicists to more clearly resolve the energy of the coated Rydberg atoms in a way that revealed previously unseen universal characteristics.

    “I give a lot of credit to the theorists,” said Killian, a professor of physics and astronomy. “They developed powerful techniques to calculate the structure of hundreds of interacting particles in order to interpret our results and identify the signatures of the Rydberg polarons.

    “From an experimental standpoint, it was challenging to make and measure these polarons,” he said. “Each one lived for only a few microseconds before collisions with other particles tore it apart. We had to use very sensitive techniques to count these fragile and fleeting objects.”

    Study co-authors include Joe Whalen, Roger Ding and Barry Dunning, all of Rice; Francisco Camargo, formerly of Rice and now of AMD; Germano Woehl Jr., formerly of Rice and now of the University of the São Paulo; Shuhei Yoshida and Joachim Burgdörfer of Vienna University of Technology; Hossein Sadeghpour of the Harvard-Smithsonian Center for Astrophysics; and Richard Schmidt and Eugene Demler of Harvard University.

    The research was supported by the Air Force Office of Scientific Research, the National Science Foundation, the Robert A. Welch Foundation, the Austrian Science Fund, the Army Research Office, Dr. Max Rössler, the Walter Haefner Foundation and the ETH Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 4:41 pm on December 18, 2017 Permalink | Reply
    Tags: , , Engineers develop microfluidic devices- microelectrodes for gentle implantation, , Nanotubes go with the flow to penetrate brain tissue, Rice University, The device uses the force applied by fast-moving fluids that gently advance insulated flexible fibers into brain tissue without buckling, The electrode is like a cooked noodle that you’re trying to put into a bowl of Jell-O” said Rice engineer Jacob Robinson   

    From Rice: “Nanotubes go with the flow to penetrate brain tissue” 

    Rice U bloc

    Rice University

    December 18, 2017
    Mike Williams

    Rice scientists, engineers develop microfluidic devices, microelectrodes for gentle implantation.

    Rice University researchers have invented a device that uses fast-moving fluids to insert flexible, conductive carbon nanotube fibers into the brain, where they can help record the actions of neurons.

    The Rice team’s microfluidics-based technique promises to improve therapies that rely on electrodes to sense neuronal signals and trigger actions in patients with epilepsy and other conditions.

    Eventually, the researchers said, nanotube-based electrodes could help scientists discover the mechanisms behind cognitive processes and create direct interfaces to the brain that will allow patients to see, to hear or to control artificial limbs.

    The device uses the force applied by fast-moving fluids that gently advance insulated flexible fibers into brain tissue without buckling. This delivery method could replace hard shuttles or stiff, biodegradable sheaths used now to deliver wires into the brain. Both can damage sensitive tissue along the way.

    The technology is the subject of a paper in the American Chemical Society journal Nano Letters.

    Lab and in vivo experiments showed how the microfluidic devices force a viscous fluid to flow around a thin fiber electrode. The fast-moving fluid slowly pulls the fiber forward through a small aperture that leads to the tissue. Once it crosses into the tissue, tests showed the wire, though highly flexible, stays straight.

    1
    Fast-moving fluid pulls a fiber through a microfluidic device to be inserted into brain tissue. The device invented at Rice University could provide a gentler method to implant wires into patients with neurological diseases and help scientists explore cognitive processes and develop implants to help people to see, to hear and to control artificial limbs. Courtesy of the Robinson Lab.

    “The electrode is like a cooked noodle that you’re trying to put into a bowl of Jell-O,” said Rice engineer Jacob Robinson, one of three project leaders. “By itself, it doesn’t work. But if you put that noodle under running water, the water pulls the noodle straight.”

    The wire moves slowly relative to the speed of the fluid. “The important thing is we’re not pushing on the end of the wire or at an individual location,” said co-author Caleb Kemere, a Rice electrical and computer engineer who specializes in neuroscience. “We’re pulling along the whole cross-section of the electrode and the force is completely distributed.”

    “It’s easier to pull things that are flexible than it is to push them,” Robinson said.

    “That’s why trains are pulled, not pushed,” said chemist Matteo Pasquali, a co-author. “That’s why you want to put the cart behind the horse.”

    The fiber moves through an aperture about three times its size but still small enough to let very little of the fluid through. Robinson said none of the fluid follows the wire into brain tissue (or, in experiments, the agarose gel that served as a brain stand-in).

    There’s a small gap between the device and the tissue, Robinson said. The small length of fiber in the gap stays on course like a whisker that remains stiff before it grows into a strand of hair. “We use this very short, unsupported length to allow us to penetrate into the brain and use the fluid flow on the back end to keep the electrode stiff as we move it down into the tissue,” he said.

    “Once the wire is in the tissue, it’s in an elastic matrix, supported all around by the gel material,” said Pasquali, a carbon nanotube fiber pioneer whose lab made a custom fiber for the project. “It’s supported laterally, so the wire can’t easily buckle.”

    Carbon nanotube fibers conduct electrons in every direction, but to communicate with neurons, they can be conductive at the tip only, Kemere said. “We take insulation for granted. But coating a nanotube thread with something that will maintain its integrity and block ions from coming in along the side is nontrivial,” he said.

    Sushma Sri Pamulapati, a graduate student in Pasquali’s lab, developed a method to coat a carbon nanotube fiber and still keep it between 15 to 30 microns wide, well below the width of a human hair. “Once we knew the size of the fiber, we fabricated the device to match it,” Robinson said. “It turned out we could make the exit channel two or three times the diameter of the electrode without having a lot of fluid come through.”

    2
    Rice University researchers have developed a method using microfluidics to implant conductive, thin, flexible fibers into brain tissue. Implanted wires could help patients with neurological diseases and help scientists explore cognitive processes and develop implants to help people to see, to hear and to control artificial limbs. Click on the image for a larger version. Courtesy of the Robinson Lab.

    The researchers said their technology may eventually be scaled to deliver into the brain at once multiple microelectrodes that are closely packed; this would make it safer and easier to embed implants. “Because we’re creating less damage during the implantation process, we might be able to put more electrodes into a particular region than with other approaches,” Robinson said.

    Flavia Vitale, a Rice alumna and now a research instructor at the University of Pennsylvania, and Daniel Vercosa, a Rice graduate student, are lead authors of the paper. Co-authors are postdoctoral fellow Alexander Rodriguez, graduate students Eric Lewis, Stephen Yan and Krishna Badhiwala and alumnus Mohammed Adnan of Rice; postdoctoral researcher Frederik Seibt and Michael Beierlein, an associate professor of neurobiology and anatomy at McGovern Medical School at the University of Texas Health Science Center at Houston; and Gianni Royer-Carfagni, a professor of structural mechanics at the University of Parma, Italy.

    Robinson and Kemere are assistant professors of electrical and computer engineering and adjunct assistant professors at Baylor College of Medicine. Pasquali is a professor of chemical and biomolecular engineering, of materials science and nanoengineering and of chemistry and chair of Rice’s Department of Chemistry.

    Supporting the research are the Defense Advanced Research Projects Agency, the Welch Foundation, the National Science Foundation, the Air Force Office of Scientific Research, the American Heart Association, the National Institutes of Health, the Citizens United for Research in Epilepsy Taking Flight Award and the Dan L. Duncan Family Foundation.

    See the full article here .

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    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
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