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  • richardmitnick 9:33 pm on December 14, 2016 Permalink | Reply
    Tags: , Light provides pull for future nanocatalyst measurement, , Rice U   

    From Rice: “Light provides pull for future nanocatalyst measurement” 

    Rice U bloc

    Rice University

    December 14, 2016
    David Ruth
    713-348-6327
    david@rice.edu

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

    Rice University photonics lab tests photon-induced force microscopy

    1
    An illustration (left) depicts the technique known as “photo-induced force microscopy,” and the images at right show how closely the experimental and theoretical findings match in a recent investigation of the technique at Rice University. Illustration by Chloe Doiron/Rice University. Reprinted with permission from Nano Letters 2016, Articles ASAP, DOI: 10.1021/acs.nanolett.6b04245. Copyright 2016 American Chemical Society.

    Rice University nanophotonics researcher Isabell Thomann uses lasers, light-activated materials and light-measuring nanoscale tips to push the boundaries of experimental nanoscience, but light is providing the pull in her latest study.

    In a new paper in the American Chemical Society journal Nano Letters [link is in image caption], Thomann and colleagues, including postdoctoral fellow Thejaswi Tumkur and graduate student Xiao Yang, combine experiment and theory to test a new technique called “photo-induced force microscopy,” which probes the optical properties of nanomaterials by measuring the physical force imparted by light.

    Thomann’s primary research centers on using nanoparticles and sunlight to reduce the carbon footprint of power plants. The work crosses boundaries of chemistry, optics, electrical engineering, energy and the environment, but a major focus is photocatalysis, a class of processes in which light interacts with high-tech materials to drive chemical reactions.

    “Many experiments nowadays are done under high vacuum, but I want to run the reactor in my lab under more realistic conditions — normal temperature, normal pressure, in the presence of water — that will apply to capturing sunlight for photocatalysis,” said Thomann, an assistant professor of electrical and computer engineering, of materials science and nanoengineering and of chemistry at Rice

    Thomann has been working to develop new tools for measuring nanomaterials since arriving at Rice in 2012. She and her team are developing an ultrafast laser spectroscopy system that can read the optical signatures of short-lived chemical processes that are relevant to artificial photosynthesis.

    “In a chemical reaction, there are reactants, which are the chemical inputs, and there are products, which are the outputs,” Thomann said. “Almost all reactions driven by light involve multiple steps where light is converted to quantum particulates such as electrons or phonons that need to be transported to surfaces to drive chemical reactions. It is very helpful to know exactly what these are, when they are made and in what quantity, particularly if you are optimizing a process for industrial use.”

    Thomann’s group designs light-activated nanoparticles that can capture energy from sunlight and use it to initiate chemical reactions. The nanocatalysts, which can be tiny rods or discs of metal or other materials, interact with light due in part to their shapes and how closely they are spaced together. Thomann said that while engineers make every effort to produce uniform particles, small imperfections still exist and can have significant consequences on performance.

    3
    These images show the measured optical forces for an array of plasmonic gold disc pairs known as dimers that were probed by an atomic force microscopy tip. The map reveals slight differences caused by minute imperfections in the dimers. Image courtesy of the Thomann Group/Rice University. Reprinted with permission from Nano Letters 2016, Articles ASAP, DOI: 10.1021/acs.nanolett.6b04245. Copyright 2016 American Chemical Society.

    “Photocatalysts are often heterogeneous, which means they are not all exactly alike, and we need better tools for examining them with high spatial resolution in order to see these small differences,” she said. “We also need to follow the reaction processes with high temporal resolution, and we want to do all of this with much better spatial resolution than can be achieved with a normal optical microscope.”

    In the photon-induced force microscopy experiments, Thomann’s team used a tiny tip from an atomic force microscope (AFM) to enhance the spatial resolution of measurements taken from gold nanorods and nanodiscs on glass surfaces. The rods and discs, which are smaller than the wavelength of light used to measure them, would normally be blurry in an optical microscope due to a physical property called the diffraction limit. To better resolve the nanoparticles, and the electromagnetic interactions between them, Thomann’s group shines light at the particles and uses an AFM tip to probe how these nanoparticles act as optical nanoantennas and concentrate the light.

    “If we were trying to measure the reflected light, it would be very difficult because there are only a few scattered photons against a very busy background where light is bouncing all over the place, especially if these measurements were carried out in a liquid environment,” Thomann said. “But we are instead measuring the force exerted on the AFM tip, the slight pull on the tip when the optical nanoantennas are illuminated by light. It turns out that measuring the force is a much more sensitive technique than trying to collect the few photons scattered off the tip.”

    Thomann said the study provides theoretical understanding of how photo-induced force microscopy works and lays the groundwork for future studies of more complex photocatalyst materials her team hopes to create in the future. She credited her group’s improved understanding of the force-measuring technique to months of hard work by co-author Xiao Yang, a Rice graduate student in the group of theoretical physicist and study co-author Peter Nordlander.

    Yang said the most difficult part of coming up with an explanation of the team’s experimental results was creating a solvable computational model that accurately described the real-world physics. For example, including the entire tip in the model made the mathematics impractical.

    “I did try, at first, but it turned out it was impossible,” Yang said. “It would have taken an infinite time to reach convergence of the simulations.”

    Yang eventually hit upon an idea — including just a portion of the tip in the model — that made the calculations both feasible and accurate. Thomann said this was just one example of Yang’s tenacity in finding a workable solution.

    “He is exactly the kind of graduate student we want: knowledgeable, hard-working and unwilling to quit in the face of adversity,” she said.

    Tumkur is a member of the Thomann research group and a J. Evans Attwell-Welch Postdoctoral Fellow at Rice’s Smalley-Curl Institute. Additional co-authors include Benjamin Cerjan and Smalley-Curl Institute Director Naomi Halas, Rice’s Stanley C. Moore Professor of Electrical and Computer Engineering, professor of chemistry, of bioengineering, of physics and astronomy, and of materials science and nanoengineering. The research was supported by the Welch Foundation, the National Science Foundation and the Smalley-Curl Institute’s J. Evans Attwell-Welch Postdoctoral Fellowship Program.

    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 7:59 pm on September 12, 2016 Permalink | Reply
    Tags: , , Rice U   

    From Rice: “New tools join breast cancer fight” 

    Rice U bloc

    Rice University

    Sept. 12, 2016
    Jeff Falk
    713-348-6775
    jfalk@rice.edu

    Mike Williams
    713-348-6728
    mikewilliams@rice.edu

    International team finds existing drug may halt tumor growth, points way toward more effective treatments

    An international team including Rice University researchers has discovered a way to fight the overexpression of a protein associated with the proliferation of breast cancer.

    Dialing down the level of the protein NAF-1 and the activity of the iron-sulfur clusters it transports may be key to halting tumor growth, they reported.

    In a study this week in the Proceedings of the National Academy of Sciences, the researchers suggest a drug that is typically used to treat type 2 diabetes, pioglitazone, has proven effective at controlling NAF-1 levels.

    They also discovered that a single mutation to NAF-1 almost completely blocked the ability of cancer cells to proliferate, a result they said supports the idea that lowering NAF-1 expression can help stop tumors.

    Fine-tuning the drug to specifically address tumors could bring a new weapon to the battle against breast cancer and other cancers, the researchers said. Overexpression of NAF-1 also has been associated with prostate, gastric, cervical, liver and laryngeal cancer, they said.

    José Onuchic, Rice’s Harry C. and Olga K. Wiess Chair of Physics and professor of physics and astronomy and co-director of the Center for Theoretical Biological Physics (CTBP), worked with Rice research scientist Mingyang Lu, Rice postdoc Fang Bai and scientists from Israel, the University of California, San Diego (UCSD) and the University of North Texas on a multifaceted approach to define the role of NAF-1 in breast cancers.

    Understanding the mechanism will help the Rice researchers improve computer simulations to aid in the rapid design and testing of novel drugs, Onuchic said.

    NAF-1 is a member of the NEET family of proteins; these proteins transport clusters of iron and sulfur molecules inside cells. The clusters help regulate processes in cells by controlling reduction-oxidation (redox) and metabolic activity. They naturally adhere to the outer surface of the mitochondria, the “power plant” that supplies cells with chemical energy.

    Experiments demonstrated that the overexpression of NAF-1 in breast cancer tumors enhanced cancer cells’ ability to tolerate oxidative stress. That enhancement allowed the tumors to become much larger and more aggressive, said Ron Mittler, a professor of biological sciences at the University of North Texas.

    “Now that we know tumors that overexpress this protein are more sensitive to this type of drug, we can design new drugs in a way that will attack the clusters,” Mittler said.

    NAF-1 “is kind of like a seesaw,” said Patricia Jennings, a CTBP affiliate and a professor of chemistry and biochemistry at UCSD. “It’s a sensor that tells your cells when they’re getting out of balance and works very hard to bring them back. But once they get a little too far out of balance, the cells can die.”

    Treating the tumors with pioglitazone stabilized the iron-sulfur clusters in NAF-1, reducing the tumors’ tolerance to oxidation. “We now have examples of five or six different types of tumors that need this protein to proliferate,” Mittler said. “If they don’t have it, they die.”

    The team also discovered through experiments that expression of an NAF-1 protein that carried a single-point mutation had a similarly toxic effect on cancer cells and prevented tumor proliferation.

    Study co-author Rachel Nechushtai, a professor at the Hebrew University of Jerusalem, said tumors depend on the lability, or the transient nature, of the clusters. “The more NAF-1 you make, and the more its clusters can be transferred, the bigger the tumor develops.

    “We knew from previous studies that pioglitazone stabilizes the cluster. With the mutant, we hardly got any tumors and didn’t see angiogenesis (the process through which new blood vessels form). When we did see tumors, they were white, not red, because they had no blood vessels.

    “We thought, ‘How do we connect this to the clinics?’ The only connection was to try a drug that, like the mutation, also stabilizes the cluster,” she said. “Fang showed in her simulations where the binding site is and why the drug stabilizes the cluster.”

    “This is where the initial results from Fang are very nice, because she can show exactly how to modify the drug,” said Onuchic, whose lab specializes in predicting protein folding pathways through computer modeling. “That way, one can computationally design the drug before trying to make the real drug. It’s a much less expensive way to come up with possibilities.”

    Bai said, “We can design selective drugs that only bind to NAF-1 and not to other proteins to reduce the side effects based on our new method.”

    Lu, Merav Darash-Yahana of Hebrew University of Jerusalem and Yair Pozniak of Tel Aviv University are lead authors of the paper. Co-authors are Yang-Sung Sohn, Ola Karmi and Sagi Tamir of Hebrew University of Jerusalem, Luhua Song of the University of North Texas, Eli Pikarsky of the Hebrew University-Hadassah Medical School and Tamar Geiger of Tel Aviv University.

    The research was supported by the Israel Science Foundation, the University of North Texas College of Arts and Sciences, the Israel Cancer Research Fund, the National Science Foundation, the Cancer Prevention and Research Institute of Texas, the Keck Center for Interdisciplinary Bioscience Training of the Gulf Coast Consortia, the Welch Foundation and the National Institutes of Health.

    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 6:52 am on September 6, 2016 Permalink | Reply
    Tags: , , Nanodiamonds in an instant, , Rice U   

    From Rice: “Nanodiamonds in an instant” 

    Rice U bloc

    Rice University

    September 6, 2016

    David Ruth
    713-348-6327
    david@rice.edu

    Mike Williams
    713-348-6728
    mikewilliams@rice.edu

    Rice University-led team morphs nanotubes into tougher carbon for spacecraft, satellites

    1
    Experiments at Rice University showed nanodiamonds and other forms of carbon were created when carbon nanotube pellets were fired at a target at hypervelocity. (Credit: Illustration by Pedro Alves da Silva Autreto)

    Superman can famously make a diamond by crushing a chunk of coal in his hand, but Rice University scientists are employing a different tactic.

    Rice materials scientists are making nanodiamonds and other forms of carbon by smashing nanotubes against a target at high speeds. Nanodiamonds won’t make anyone rich, but the process of making them will enrich the knowledge of engineers who design structures that resist damage from high-speed impacts.

    The diamonds are the result of a detailed study on the ballistic fracturing of carbon nanotubes at different velocities. The results showed that such high-energy impacts caused atomic bonds in the nanotubes to break and sometimes recombine into different structures.

    The work led by the labs of materials scientists Pulickel Ajayan at Rice and Douglas Galvao at the State University of Campinas, Brazil, is intended to help aerospace engineers design ultralight materials for spacecraft and satellites that can withstand impacts from high-velocity projectiles like micrometeorites.

    The research appears in the American Chemical Society journal ACS Applied Materials and Interfaces.

    Knowing how the atomic bonds of nanotubes can be recombined will give scientists clues to develop lightweight materials by rearranging those bonds, said co-lead author and Rice graduate student Sehmus Ozden.

    “Satellites and spacecraft are at risk of various destructive projectiles, such as micrometeorites and orbital debris,” Ozden said. “To avoid this kind of destructive damage, we need lightweight, flexible materials with extraordinary mechanical properties. Carbon nanotubes can offer a real solution.”

    The researchers packed multiwalled carbon nanotubes into spherical pellets and fired them at an aluminum target in a two-stage light-gas gun at Rice, and then analyzed the results from impacts at three different speeds.

    At what the researchers considered a low velocity of 3.9 kilometers per second, a large number of nanotubes were found to remain intact. Some even survived higher velocity impacts of 5.2 kilometers per second. But very few were found among samples smashed at a hypervelocity of 6.9 kilometers per second. The researchers found that many, if not all, of the nanotubes split into nanoribbons, confirming earlier experiments.

    Co-author Chandra Sekhar Tiwary, a Rice postdoctoral researcher, noted the few nanotubes and nanoribbons that survived the impact were often welded together, as observed in transmission electron microscope images.

    “In our previous report, we showed that carbon nanotubes form graphene nanoribbons at hypervelocity impact,” Tiwary said. “We were expecting to get welded carbon nanostructures, but we were surprised to observe nanodiamond as well.”

    The orientation of nanotubes both to each other and in relation to the target and the number of tube walls were as important to the final structures as the velocity, Ajayan said.

    “The current work opens a new way to make nanosize materials using high-velocity impact,” said co-lead author Leonardo Machado of the Brazil team.

    Machado is a graduate student at the State University of Campinas, Brazil, and the Federal University of Rio Grande do Norte, Brazil. Co-authors are Rice’s Robert Vajtai, an associate research professor, and Enrique Barrera, a professor of materials science and nanoengineering, and Pedro Alves da Silva of the State University of Campinas and the Federal University of ABC, Santo Andre, Brazil. Ajayan is chair of Rice’s Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.

    The research was supported by the Department of Defense, the U.S. Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative, NASA’s Johnson Space Center, the Sao Paulo Research Foundation, the Center for Computational Engineering and Sciences at Unicamp, Brazil, and the Brazilian Federal Agency for Support and Evaluation of Graduate Education.

    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 11:31 am on September 5, 2016 Permalink | Reply
    Tags: , , , Rice U, Study: Earth’s carbon points to planetary smashup   

    From Rice- “Study: Earth’s carbon points to planetary smashup” 

    Rice U bloc

    Rice University

    September 5, 2016
    Jade Boyd

    Element ratios suggest Earth collided with Mercury-like planet

    1
    The ratio of volatile elements in Earth’s mantle suggests that virtually all of the planet’s life-giving carbon came from a collision with an embryonic planet approximately 100 million years after Earth formed. (Image by A. Passwaters/Rice University based on original courtesy of NASA/JPL-Caltech at http://www.nasa.gov/multimedia/imagegallery/image_feature_1454.html)

    Research by Rice University Earth scientists suggests that virtually all of Earth’s life-giving carbon could have come from a collision about 4.4 billion years ago between Earth and an embryonic planet similar to Mercury.

    In a new study this week in Nature Geoscience, Rice petrologist Rajdeep Dasgupta and colleagues offer a new answer to a long-debated geological question: How did carbon-based life develop on Earth, given that most of the planet’s carbon should have either boiled away in the planet’s earliest days or become locked in Earth’s core?

    “The challenge is to explain the origin of the volatile elements like carbon that remain outside the core in the mantle portion of our planet,” said Dasgupta, who co-authored the study with lead author and Rice postdoctoral researcher Yuan Li, Rice research scientist Kyusei Tsuno and Woods Hole Oceanographic Institute colleagues Brian Monteleone and Nobumichi Shimizu.

    Dasgupta’s lab specializes in recreating the high-pressure and high-temperature conditions that exist deep inside Earth and other rocky planets. His team squeezes rocks in hydraulic presses that can simulate conditions about 250 miles below Earth’s surface or at the core-mantle boundary of smaller planets like Mercury.

    “Even before this paper, we had published several studies that showed that even if carbon did not vaporize into space when the planet was largely molten, it would end up in the metallic core of our planet, because the iron-rich alloys there have a strong affinity for carbon,” Dasgupta said.

    Earth’s core, which is mostly iron, makes up about one-third of the planet’s mass. Earth’s silicate mantle accounts for the other two-thirds and extends more than 1,500 miles below Earth’s surface. Earth’s crust and atmosphere are so thin that they account for less than 1 percent of the planet’s mass. The mantle, atmosphere and crust constantly exchange elements, including the volatile elements needed for life.

    If Earth’s initial allotment of carbon boiled away into space or got stuck in the core, where did the carbon in the mantle and biosphere come from?

    “One popular idea has been that volatile elements like carbon, sulfur, nitrogen and hydrogen were added after Earth’s core finished forming,” said Li, who is now a staff scientist at Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. “Any of those elements that fell to Earth in meteorites and comets more than about 100 million years after the solar system formed could have avoided the intense heat of the magma ocean that covered Earth up to that point.

    “The problem with that idea is that while it can account for the abundance of many of these elements, there are no known meteorites that would produce the ratio of volatile elements in the silicate portion of our planet,” Li said.

    In late 2013, Dasgupta’s team began thinking about unconventional ways to address the issue of volatiles and core composition, and they decided to conduct experiments to gauge how sulfur or silicon might alter the affinity of iron for carbon. The idea didn’t come from Earth studies, but from some of Earth’s planetary neighbors.

    “We thought we definitely needed to break away from the conventional core composition of just iron and nickel and carbon,” Dasgupta recalled. “So we began exploring very sulfur-rich and silicon-rich alloys, in part because the core of Mars is thought to be sulfur-rich and the core of Mercury is thought to be relatively silicon-rich.

    2
    Schematic depiction of proto Earth’s merger with a potentially Mercury-like planetary embryo, a scenario supported by new high pressure-temperature experiments at Rice University. Magma ocean processes could lead planetary embryos to develop silicon- or sulfur-rich metallic cores and carbon-rich outer layers. If Earth merged with such a planet early in its history, it could explain how Earth acquired its carbon and sulfur. (Figure courtesy of Rajdeep Dasgupta)

    “It was a compositional spectrum that seemed relevant, if not for our own planet, then definitely in the scheme of all the terrestrial planetary bodies that we have in our solar system,” he said.

    The experiments revealed that carbon could be excluded from the core — and relegated to the silicate mantle — if the iron alloys in the core were rich in either silicon or sulfur.

    “The key data revealed how the partitioning of carbon between the metallic and silicate portions of terrestrial planets varies as a function of the variables like temperature, pressure and sulfur or silicon content,” Li said.

    The team mapped out the relative concentrations of carbon that would arise under various levels of sulfur and silicon enrichment, and the researchers compared those concentrations to the known volatiles in Earth’s silicate mantle.

    “One scenario that explains the carbon-to-sulfur ratio and carbon abundance is that an embryonic planet like Mercury, which had already formed a silicon-rich core, collided with and was absorbed by Earth,” Dasgupta said. “Because it’s a massive body, the dynamics could work in a way that the core of that planet would go directly to the core of our planet, and the carbon-rich mantle would mix with Earth’s mantle.

    “In this paper, we focused on carbon and sulfur,” he said. “Much more work will need to be done to reconcile all of the volatile elements, but at least in terms of the carbon-sulfur abundances and the carbon-sulfur ratio, we find this scenario could explain Earth’s present carbon and sulfur budgets.”

    The research was supported by NASA and the National Science 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 1:47 pm on August 15, 2016 Permalink | Reply
    Tags: , Graphene nanoribbons in solutions mimic nature, , Rice U   

    From Rice: “Nanoribbons in solutions mimic nature” 

    Rice U bloc

    Rice University

    August 15, 2016
    Mike Williams

    Rice University scientists test graphene ribbons’ abilities to integrate with biological systems

    1
    The tip of an atomic force microscope on a cantilevered arm is used to pull a graphene nanoribbon the same way it would be used to pull apart a protein or a strand of DNA in a Rice University lab. The microscope can be used to measure properties like rigidity in a material as it’s manipulated by the tip. (Credit: Kiang Research Group/Rice University)

    Graphene nanoribbons (GNRs) bend and twist easily in solution, making them adaptable for biological uses like DNA analysis, drug delivery and biomimetic applications, according to scientists at Rice University.

    Knowing the details of how GNRs behave in a solution will help make them suitable for wide use in biomimetics, according to Rice physicist Ching-Hwa Kiang, whose lab employed its unique capabilities to probe nanoscale materials like cells and proteins in wet environments. Biomimetic materials are those that imitate the forms and properties of natural materials.

    1
    Rice University physicist Ching-Hwa Kiang, left, and graduate student Jingqiang Li analyze readings at the atomic force microscope in her lab. The researchers analyzed the properties of carbon nanoribbons in solutions with the equipment they normally use to analyze DNA, proteins and cells. (Credit: Rice University)

    The research led by recent Rice graduate Sithara Wijeratne, now a postdoctoral researcher at Harvard University, appears in the Nature journal Scientific Reports.

    3
    Rice University physicist Ching-Hwa Kiang, left, and alumna Sithara Wijeratne led a study to determine the mechanical properties of graphene nanoribbons in solution. They found the nanoribbons mimic the properties of natural polymers like proteins and DNA and may be suitable for biomimetic applications. (Credit: Jeff Fitlow/Rice University)

    Graphene nanoribbons can be thousands of times longer than they are wide. They can be produced in bulk by chemically “unzipping” carbon nanotubes, a process invented by Rice chemist and co-author James Tour and his lab.

    Their size means they can operate on the scale of biological components like proteins and DNA, Kiang said. “We study the mechanical properties of all different kinds of materials, from proteins to cells, but a little different from the way other people do,” she said. “We like to see how materials behave in solution, because that’s where biological things are.” Kiang is a pioneer in developing methods to probe the energy states of proteins as they fold and unfold.

    She said Tour suggested her lab have a look at the mechanical properties of GNRs. “It’s a little extra work to study these things in solution rather than dry, but that’s our specialty,” she said.

    Nanoribbons are known for adding strength but not weight to solid-state composites, like bicycle frames and tennis rackets, and forming an electrically active matrix. A recent Rice project infused them into an efficient de-icer coating for aircraft.

    But in a squishier environment, their ability to conform to surfaces, carry current and strengthen composites could also be valuable.

    “It turns out that graphene behaves reasonably well, somewhat similar to other biological materials. But the interesting part is that it behaves differently in a solution than it does in air,” she said. The researchers found that like DNA and proteins, nanoribbons in solution naturally form folds and loops, but can also form helicoids, wrinkles and spirals.

    Kiang, Wijeratne and Jingqiang Li, a co-author and student in the Kiang lab, used atomic force microscopy to test their properties. Atomic force microscopy can not only gather high-resolution images but also take sensitive force measurements of nanomaterials by pulling on them. The researchers probed GNRs and their precursors, graphene oxide nanoribbons.

    The researchers discovered that all nanoribbons become rigid under stress, but their rigidity increases as oxide molecules are removed to turn graphene oxide nanoribbons into GNRs. They suggested this ability to tune their rigidity should help with the design and fabrication of GNR-biomimetic interfaces.

    “Graphene and graphene oxide materials can be functionalized (or modified) to integrate with various biological systems, such as DNA, protein and even cells,” Kiang said. “These have been realized in biological devices, biomolecule detection and molecular medicine. The sensitivity of graphene bio-devices can be improved by using narrow graphene materials like nanoribbons.”

    Wijeratne noted graphene nanoribbons are already being tested for use in DNA sequencing, in which strands of DNA are pulled through a nanopore in an electrified material. The base components of DNA affect the electric field, which can be read to identify the bases.

    The researchers saw nanoribbons’ biocompatibility as potentially useful for sensors that could travel through the body and report on what they find, not unlike the Tour lab’s nanoreporters that retrieve information from oil wells.

    Further studies will focus on the effect of the nanoribbons’ width, which range from 10 to 100 nanometers, on their properties.

    Co-authors are Rice research scientist Evgeni Penev; graduate student Wei Lu; alumna Amanda Duque, now a scientist at Los Alamos National Laboratory; and Boris Yakobson, the Karl F. Hasselmann Professor of Materials Science and NanoEngineering and a professor of chemistry. Tour is the T.T. and W.F. Chao Professor of Chemistry as well as a professor of computer science and of materials science and nanoengineering. Kiang is an associate professor of physics and astronomy and of bioengineering.

    The Welch Foundation and the National Science Foundation supported the research. The researchers used the NSF’s Extreme Science and Engineering Discovery Environment and the NSF-supported DAVinCI supercomputer administered by Rice’s Center for Research Computing and procured in a partnership with Rice’s Ken Kennedy Institute.

    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 5:25 am on July 26, 2016 Permalink | Reply
    Tags: , , Rice U, Spider silk, Spiders spin unique phononic material   

    From Rice: “Spiders spin unique phononic material” 

    Rice U bloc

    Rice University

    July 25, 2016
    Mike Williams

    Researchers at Rice University, in Europe and in Singapore discover band gaps in spider silk

    1
    Scientists at Rice University and in Europe and Singapore studied the microstructure of spider silk to see how it transmits phonons, quanta of sound that also have thermal properties. They suggested what they learned could be useful to create strong synthetic fibers with silk-like properties. Click on the image for a larger version. Illustration by Dirk Schneider

    New discoveries about spider silk could inspire novel materials to manipulate sound and heat in the same way semiconducting circuits manipulate electrons, according to scientists at Rice University, in Europe and in Singapore.

    A paper in Nature Materials looks at the microscopic structure of spider silk and reveals unique characteristics in the way it transmits phonons, quasiparticles of sound.

    The research shows for the first time that spider silk has a phonon band gap. That means it can block phonon waves in certain frequencies in the same way an electronic band gap – the basic property of semiconducting materials – allows some electrons to pass and stops others.

    The researchers wrote that their observation is the first discovery of a “hypersonic phononic band gap in a biological material.”

    How the spider uses this property remains to be understood, but there are clear implications for materials, according to materials scientist and Rice Engineering Dean Edwin Thomas, who co-authored the paper. He suggested that the crystalline microstructure of spider silk might be replicated in other polymers. That could enable tunable, dynamic metamaterials like phonon waveguides and novel sound or thermal insulation, since heat propagates through solids via phonons.

    “Phonons are mechanical waves,” Thomas said, “and if a material has regions of different elastic modulus and density, then the waves sense that and do what waves do: They scatter. The details of the scattering depend on the arrangement and mechanical couplings of the different regions within the material that they’re scattering from.”

    Spiders are adept at sending and reading vibrations in a web, using them to locate defects and to know when “food” comes calling. Accordingly, the silk has the ability to transmit a wide range of sounds that scientists think the spider can interpret in various ways. But the researchers found silk also has the ability to dampen some sound.

    “(Spider) silk has a lot of different, interesting microstructures, and our group found we could control the position of the band gap by changing the strain in the silk fiber,” Thomas said. “There’s a range of frequencies that are not allowed to propagate. If you broadcast sound at a particular frequency, it won’t go into the material.”

    In 2005, Thomas teamed with George Fytas, a materials scientist at the University of Crete and the Institute of Electronic Structure and Laser Foundation for Research and Technology-Hellas, Greece, on a project to define the properties of hypersonic phononic crystals. In that work, the researchers measured phonon propagation and detected band gaps in synthetic polymer crystals aligned at regular intervals.

    “Phononic crystals give you the ability to manipulate sound waves, and if you get sound small enough and at high enough frequencies, you’re talking about heat,” Thomas said. “Being able to make heat flow this way and not that way, or make it so it can’t flow at all, means you’re turning a material into a thermal insulator that wasn’t one before.”

    Fytas and Thomas decided to take a more detailed look at dragline silk, which spiders use to construct a web’s outer rim and spokes and as a lifeline. (A spider suspended in midair is clinging to a dragline.) Though silk has been studied for thousands of years, it has only recently been analyzed for its acoustic properties.

    Silk is a hierarchical structure comprised of a protein, which folds into sheets and forms crystals. These hard protein crystals are interconnected by softer, amorphous chains, Thomas said. Stretching or relaxing the interconnecting chains changes the silk’s acoustic properties by adjusting the mechanical coupling between the crystals.

    Fytas’ team at the Max Planck Institute for Polymer Research in Mainz, Germany, performed Brillouin light scattering experiments to test silk placed under varying degrees of stress. “That was George’s genius,” Thomas said. “With Brillouin scattering, you use light to create phonons as well as absorb them from the sample. BLS allows you to see how the phonons move around inside any object, depending on the temperature and the material’s microstructure.”

    They found that when silk was “super contracted,” the velocity of phonons decreased by 15 percent while the bandwidth of frequencies it could block increased by 31 percent. Conversely, when strained, the velocity increased by about 27 percent, while the bandwidth decreased by 33 percent. They first observed a band gap in native (uncontracted) silk at about 14.8 gigahertz, with a width of about 5.2 gigahertz.

    Just as interesting to the team was the “unique region of negative group velocity” they witnessed. At these conditions, even though phonon waves moved forward, the phase velocity moved backward, Thomas said. They suggested the effect may allow for the focusing of hypersonic phonons.

    “Right now, we don’t know how to do any of this in other macromolecular fiber materials,” Thomas said. “There’s been a fair amount of investigation on synthetic polymers like nylon, but nobody’s ever found a band gap.”

    Co-authors of the paper are Dirk Schneider of ebeam Technologies, Bern, Switzerland, and Nikolaos Gomopoulos of the Swiss Federal Institute of Technology in Lausanne, both formerly of the Max Planck Institute; Cheong Koh of DSO National Laboratories, Singapore; Periklis Papadopoulos of the Planck Institute and the University of Ioannina, Greece; and Friedrich Kremer of the Institute of Experimental Physics at the University of Leipzig, Germany. Fytas is a professor at the University of Crete and has an appointment at the Planck Institute. Thomas is the William and Stephanie Sick Dean of Rice’s George R. Brown School of Engineering, a professor of materials science and nanoengineering and of chemical and biomolecular engineering.

    The Aristeia Alliance of the Mediterranean Institute for Scientific Research, the European Research Council, the Sonderforschungsbereich/Transregio (Collaborative Research Center) and the Deutsch Forschungsgemeinschaft (German Research Foundation) supported the research.

    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 11:03 am on July 25, 2016 Permalink | Reply
    Tags: , Rice U, Ultra-flat circuits will have unique properties   

    From Rice: “Ultra-flat circuits will have unique properties” 

    Rice U bloc

    Rice University

    July 25, 2016
    Mike Williams

    Rice University lab studies 2-D hybrids to see how they differ from common electronics

    The old rules don’t necessarily apply when building electronic components out of two-dimensional materials, according to scientists at Rice University.

    The Rice lab of theoretical physicist Boris Yakobson analyzed hybrids that put 2-D materials like graphene and boron nitride side by side to see what happens at the border. They found that the electronic characteristics of such “co-planar” hybrids differ from bulkier components.

    Their results appear this month in the American Chemical Society journal Nano Letters.

    Shrinking electronics means shrinking their components. Academic labs and industries are studying how materials like graphene may enable the ultimate in thin devices by building all the necessary circuits into an atom-thick layer.

    1
    Hybrids of two-dimensional materials like the graphene-molybdenum disulfide illustrated here have electronic properties that don’t follow the same rules as their 3-D cousins, according to Rice University researchers. The limited direct contact between the two materials creates an electric field that greatly increases the size of the p/n junction. Illustration by Henry Yu

    “Our work is important because semiconductor junctions are a big field,” Yakobson said. “There are books with iconic models of electronic behavior that are extremely well-developed and have become the established pillars of industry.

    “But these are all for bulk-to-bulk interfaces between three-dimensional metals,” he said. “Now that people are actively working to make two-dimensional devices, especially with co-planar electronics, we realized that the rules have to be reconsidered. Many of the established models utilized in industry just don’t apply.”

    The researchers led by Rice graduate student Henry Yu built computer simulations that analyze charge transfer between atom-thick materials.

    “It was a logical step to test our theory on both metals and semiconductors, which have very different electronic properties,” Yu said. “This makes graphene, which is a metal — or a semimetal, to be precise — molybdenum disulfide and boron nitride, which are semiconductors, or even their hybrids ideal systems to study.

    “In fact, these materials have been widely fabricated and used in the community for almost a decade, which makes analysis of them more appreciable in the field. Furthermore, both hybrids of graphene-molybdenum disulfide and graphene-boron nitride have been successfully synthesized recently, which means our study has practical meaning and can be tested in the lab now,” he said.

    Yakobson said 3-D materials have a narrow region for charge transfer at the positive and negative (or p/n) junction. But the researchers found that 2-D interfaces created “a highly nonlocalized charge transfer” — and an electric field along with it — that greatly increased the junction size. That could give them an advantage in photovoltaic applications like solar cells, the researchers said.

    The lab built a simulation of a hybrid of graphene and molybdenum disulfide and also considered graphene-boron nitride and graphene in which half was doped to create a p/n junction. Their calculations predicted the presence of an electric field should make 2-D Schottky (one-way) devices like transistors and diodes more tunable based on the size of the device itself.

    How the atoms line up with each other is also important, Yakobson said. Graphene and boron nitride both feature hexagonal lattices, so they mesh perfectly. But molybdenum disulfide, another promising material, isn’t exactly flat, though it’s still considered 2-D.

    “If the atomic structures don’t match, you get dangling bonds or defects along the borderline,” he said. “The structure has consequences for electronic behavior, especially for what is called Fermi level pinning.”

    Pinning can degrade electrical performance by creating an energy barrier at the interface, Yakobson explained. “But your Schottky barrier (in which current moves in only one direction) doesn’t change as expected. This is a well-known phenomenon for semiconductors; it’s just that in two dimensions, it’s different, and in this case may favor 2-D over 3-D systems.”

    Yakobson said the principles put forth by the new paper will apply to patterned hybrids of two or more 2-D patches. “You can make something special, but the basic effects are always at the interfaces. If you want to have many transistors in the same plane, it’s fine, but you still have to consider effects at the junctions.

    “There’s no reason we can’t build 2-D rectifiers, transistors or memory elements,” he said. “They’ll be the same as we use routinely in devices now. But unless we develop a proper fundamental knowledge of the physics, they may fail to do what we design or plan.”

    Rice postdoctoral research associate Alex Kutana is a co-author of the paper. Yakobson is the Karl F. Hasselmann Professor of Materials Science and NanoEngineering and a professor of chemistry.

    The Office of Naval Research supported the research.

    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 1:53 pm on July 20, 2016 Permalink | Reply
    Tags: , , Oxygenation, Rice U   

    From Rice: “Oxygen atmosphere recipe = tectonics + continents + life” 

    Rice U bloc

    Rice University

    May 16, 2016
    Jade Boyd

    1
    A view of Earth’s atmosphere taken from the International Space Station in 2003. Credit: ISS Expedition 7 Crew, EOL, NASA

    Rice-led study offers new answer to why Earth’s atmosphere became oxygenated

    Earth scientists from Rice University, Yale University and the University of Tokyo are offering a new answer to the long-standing question of how our planet acquired its oxygenated atmosphere.

    Based on a new model that draws from research in diverse fields including petrology, geodynamics, volcanology and geochemistry, the team’s findings were published online this week in Nature Geoscience. They suggest that the rise of oxygen in Earth’s atmosphere was an inevitable consequence of the formation of continents in the presence of life and plate tectonics.

    “It’s really a very simple idea, but fully understanding it requires a good bit of background about how the Earth works,” said study lead author Cin-Ty Lee, professor of Earth science at Rice. “The analogy I most often use is the leaky bathtub. The level of water in a bathtub is controlled by the rate of water flowing in through the faucet and the efficiency by which water leaks out through the drain. Plants and certain types of bacteria produce oxygen as a byproduct of photosynthesis. This oxygen production is balanced by the sink: reaction of oxygen with iron and sulfur in the Earth’s crust and by back-reaction with organic carbon. For example, we breathe in oxygen and exhale carbon dioxide, essentially removing oxygen from the atmosphere. In short, the story of oxygen in our atmosphere comes down to understanding the sources and sinks, but the 3-billion-year narrative of how this actually unfolded is more complex.”

    Lee co-authored the study with Laurence Yeung and Adrian Lenardic, both of Rice, and with Yale’s Ryan McKenzie and the University of Tokyo’s Yusuke Yokoyama. The authors’ explanations are based on a new model that suggests how atmospheric oxygen was added to Earth’s atmosphere at two key times: one about 2 billion years ago and another about 600 million years ago.

    Today, some 20 percent of Earth’s atmosphere is free molecular oxygen, or O2. Free oxygen is not bound to another element, as are the oxygen atoms in other atmospheric gases like carbon dioxide and sulfur dioxide. For much of Earth’s 4.5-billion-year history, free oxygen was all but nonexistent in the atmosphere.

    “It was not missing because it is rare,” Lee said. “Oxygen is actually one of the most abundant elements on rocky planets like Mars, Venus and Earth. However, it is one of the most chemically reactive elements. It forms strong chemical bonds with many other elements, and as a result, it tends to remain locked away in oxides that are forever entombed in the bowels of the planet — in the form of rocks. In this sense, Earth is no exception to the other planets; almost all of Earth’s oxygen still remains locked away in its deep rocky interior.”

    Lee and colleagues showed that around 2.5 billion years ago, the composition of Earth’s continental crust changed fundamentally. Lee said the period, which coincided with the first rise in atmospheric oxygen, was also marked by the appearance of abundant mineral grains known as zircons.

    “The presence of zircons is telling,” he said. “Zircons crystallize out of molten rocks with special compositions, and their appearance signifies a profound change from silica-poor to silica-rich volcanism. The relevance to atmospheric composition is that silica-rich rocks have far less iron and sulfur than silica-poor rocks, and iron and sulfur react with oxygen and form a sink for oxygen.

    “Based on this, we believe the first rise in oxygen may have been due to a substantial reduction in the efficiency of the oxygen sink,” Lee said. “In the bathtub analogy, this is equivalent to partially plugging the drain.”

    Lee said the study suggests that the second rise in atmospheric oxygen was related to a change in production — analogous to turning up the flow from the faucet.

    “The bathtub analogy is simple and elegant, but there’s an added complication that must be taken into account,” he said. “That is because oxygen production is ultimately tied to the global carbon cycle — the cycling of carbon between the Earth, the biosphere, the atmosphere and oceans.”

    Lee said the model showed that Earth’s carbon cycle has never been at a steady state because carbon slowly leaks out as carbon dioxide from Earth’s deep interior to the surface through volcanic activity. Carbon dioxide is one of the key ingredients for photosynthesis.

    “On long, geologic timescales, carbon is removed from the atmosphere by the production of condensed forms of carbon, such as organic carbon and minerals called carbonate,” he said. “For most of Earth’s history, most of this carbon has been deposited not in the deep ocean but rather on the margins of continents. The implications are profound because carbon deposited on continents does not return to Earth’s deep interior. Instead, it amplifies carbon inputs into the atmosphere when the continents are subsequently perturbed by volcanism.”

    Lee said the team’s model showed that volcanic activity and other geologic inputs of carbon into the atmosphere may have increased with time, and because oxygen production is tied to carbon production, oxygen production also must increase. The model showed that the second rise in atmospheric oxygen had to occur late in Earth’s history.

    “Exactly when is model-dependent, but what is clear is that the formation of continental crust naturally leads to two rises in atmospheric oxygen, just as we see in the fossil record,” Lee said.

    Exactly what caused the composition of the crust to change during the first oxygenation event remains a mystery, but Lee said the team believes it may have been related to the onset of plate tectonics, where the Earth’s surface, for the first time, became mobile enough to sink back down into Earth’s deep interior.

    Lee said the team’s new model is not without controversy. For example, the model predicts that production of carbon dioxide must increase with time, a finding that goes against the conventional wisdom that carbon fluxes and atmospheric carbon dioxide levels have steadily decreased over the last 4 billion years.

    “The change in flux described by our model happens over extremely long time periods, and it would be a mistake to think that these processes that are bringing about any of the atmospheric changes are occurring due to anthropomorphic climate change,” he said. “However, our work does suggest that Earth scientists and astrobiologists may need to revisit what we think we know about Earth’s early history.”

    This work is the result of an ongoing study of the global carbon cycle funded by the National Science Foundation and administered by Rice University.

    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 8:15 am on July 14, 2016 Permalink | Reply
    Tags: , Rice U, Team training in health care can save lives   

    From Rice: “Team training in health care can save lives” 

    Rice U bloc

    Rice University

    July 14, 2016
    Amy McCaig

    1
    Photo credit: Shutterstock

    Team training of health care employees can reduce patient mortality by 15 percent, according to a new study from Rice University, the Johns Hopkins University School of Medicine, the University of Central Florida, the U.S. Department of Defense and the Michael E. DeBakey VA Medical Center.

    “Saving Lives: A Meta-Analysis of Team Training in Health Care” found that team training can also reduce medical errors by 19 percent. Team training is an instructional strategy aimed at improving team-based knowledge, skills, attitudes and problem-solving interactions. It focuses on developing coordination, cooperation, communication, leadership and other team-based skills. Team members train in specific roles while performing specific tasks and interact or coordinate to achieve a common goal or outcome.

    “Medical error has an estimated economic impact between $735 billion to $980 billion annually in the United States alone,” said Eduardo Salas, the Allyn R. and Gladys M. Cline Chair and Professor of Psychology at Rice, one of the study’s authors. “In addition, estimates indicate that preventable medical errors occur in one out of every three hospital admissions. The evidence is clear: Medical error causes patient harm, and much of this error is preventable. Team training is one possible way to prevent such errors from ever happening.”

    The researchers reported that 19 percent of trainees had, in general, positive reactions to team training. (The remaining trainees were neutral on the topic.) The group training also improved employees’ learning of new skills by 31 percent and on-the-job use of these skills by 25 percent. Financial outcomes of health care organizations were improved by 15 percent. Finally, team training was associated with a 34 percent improvement in clinical performance and 15 percent increase in patient satisfaction.

    “Team training has the potential to teach individuals how to better communicate, cooperate and resolve conflicts in workplace settings, including health care,” Salas said. “Ultimately, we found that team training is effective and useful in this field and can save money and, more importantly, lives.”

    Salas said the study’s results are encouraging and demonstrate that health care organizations can see moderate to large improvements in their employees’ performance and organizational results by participating in a health care team-training program.

    The study examined the impact of training in team settings among 23,018 participants in 129 prior studies. The previous research examined how team training impacted quality of care, customer service, patient satisfaction and other variables. Participants included health care providers (physicians, nurse practitioners, physician assistants, etc.), allied health care personnel (nurses and therapists), health care staff (unit clerks) and health care students (medical students, nursing students, etc.) and came from facilities ranging from small clinics to large hospitals, both in the U.S. and abroad.

    The article will appear in an upcoming edition of the Journal of Applied Psychology and was co-authored by Ashley Hughes and Megan Gregory at the Michael E. DeBakey VA Medical Center in Houston, Dana Joseph and Shirley Sonesh at the University of Central Florida, Shannon Marlow and Christina Lacerenza at Rice, Lauren Benishek at Johns Hopkins University School of Medicine and Heidi King at the U.S. Department of Defense. NASA funded the research.

    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 10:02 am on June 28, 2016 Permalink | Reply
    Tags: , , Rice U   

    From Rice U: “Core proteins exert control over DNA function” 

    Rice U bloc

    Rice University

    June 21, 2016
    Mike Williams

    Rice University-based models simulate how nucleosomes facilitate gene exposure

    1
    Rice University scientists simulated a nucleosome coiled in DNA to discover the interactions that control its unwinding. The DNA double helix binds tightly to proteins (in red, blue, orange and green) that make up the histone core, which exerts control over the exposure (center and right) of genes for binding. Courtesy of the Wolynes Lab

    The spools at the center of nucleosomes, the fundamental unit of DNA organization, are histone protein core complexes. Nucleosomes are buried deep within a cell’s nucleus. About 147 DNA base pairs (from the more than 3 billion in the human genome) wrap around each histone core 1.7 times. The double helix moves on to spiral around the next core, and the next, with linker sections of 20 to 90 base pairs in between.

    The structure helps squeeze a 6-foot-long strand of DNA in each cell into as compact a form as possible while facilitating the controlled exposure of genes along the strand for protein expression.

    The spools consist of two pairs of heterodimers, macromolecules that join to form the core. The core is stable until genes along the DNA are called upon by transcription factors or RNA polymerases; the researchers’ goal was to simulate what happens as the DNA unwinds from the core, making itself available to bind to outside proteins or make contact with other genes along the strand.

    The researchers used their energy landscape models to simulate the nucleosome disassembly mechanism based on the energetic properties of its constituent DNA and proteins. The landscape maps the energies of all the possible forms a protein can take as it folds and functions. Conceptual insights from energy landscape theory have been implemented in an open-source biomolecular modeling framework called AWSEM Molecular Dynamics, which was jointly developed by the Papoian and Wolynes groups.

    Wolynes said most studies elsewhere treated the histone core as if it were rigid and irreversibly disassociated when DNA unwrapped. But more recent experimental studies that involved gently pulling strands of DNA or used fluorescent resonance energy transfer, which measures energy moving between two molecules, showed the protein core is flexible and does not completely disassemble during unwrapping.

    In their simulations, the researchers found the core changed its shape as the DNA unwound. Without DNA, they found the histone core was completely unstable in physiological conditions.

    Their simulations showed that histone tails – the terminal regions of the core proteins – play a crucial role in nucleosome stability. The tails are highly charged and bind tightly with DNA, keeping its genomic content from being exposed until necessary. Their models predicted a faster unwrapping for tail-less nucleosomes, as seen in experiments.

    The nucleosome study is part of a larger effort both by Papoian at Maryland and by Wolynes with his colleagues at CTBP to understand the mechanics of DNA, from how it functions to how it reproduces during mitosis. Wolynes said the new study and another new one by his lab on DNA during mitosis represent the opposite ends of the size scale.

    “We can understand things at each end of the scale, but there’s a no-man’s land in between,” he said. “We’ll have to see whether the phenomena in the present-day no-man’s land can be understood. I don’t believe in magic; I believe they eventually will.”

    Wolynes is the D.R. Bullard-Welch Foundation Professor of Science, a professor of chemistry, of biochemistry and cell biology, of physics and astronomy and of materials science and nanoengineering at Rice and a senior investigator of the National Science Foundation (NSF)-funded CTBP. Papoian is the Monroe Martin Professor and chemical physics director at the University of Maryland. Zhang will join the Massachusetts Institute of Technology as an assistant professor in July.

    The research was supported by the NSF, the CTBP and the National Institute of General Medical Sciences.

    The researchers used the NSF-supported DAVinCI supercomputer administered by Rice’s Ken Kennedy Institute for Information Technology.

    2
    IBM iDataPlex DAVinCI supercomputer

    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.

     
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