OU Radar Team Developing Testbed

The University of Oklahoma Advanced Radar Research Center is developing an all-digital  polarimetric phased array mobile radar testbed with a $5.4 million grant from the U.S. Department of Defense, Office of Naval Research, to address significant near-term obstacles and fulfill many operational missions. The ARRC team is providing a mobile radar testbed that can demonstrate multiple radar modes that increase public safety outcomes, such as weather monitoring and air traffic surveillance and control.

“The University of Oklahoma is the only university developing a system like this one,” said Mark Yeary, OU ARRC team leader and professor of electrical and computer engineering, OU Gallogly College of Engineering. “The ARRC has been successful in attracting the attention of the U.S. Navy and other agencies by building a team of experts that includes both meteorologists and engineers.”

Yeary and ARRC team members Robert Palmer, Caleb Fulton, Hjalti Sigmarsson, Jorge Salazar Cerrano and Nathan Goodman are working with Redmond Kelley, Matt McCord and John Meier, ARRC engineers on the project. The team is responsible for all aspects of the project, including electrical and mechanical design, mechanical assembly, thermal designs, data and processing control, a chiller system, truck with factory integrated generator, array positioner, enclosure and truck modifications.

“The all-digital radar can do what most radars cannot do, which is why the U.S. Navy is extremely interested in the capabilities of this mobile radar testbed. We are fully engaged in the research and development the U.S. Navy is doing and are addressing their needs with this project,” said Caleb Fulton, professor of electrical and computer engineering, Gallogly College of Engineering.

The funding from the U.S. Navy was made possible by foundational work on the so-called Horus all-digital polarimetric phased array radar done in collaboration with NOAA’s National Severe Storms Laboratory for the weather applications. The new system will build upon this work with NOAA and is defined by its flexibility and the software is easily reconfigured to address the challenges the U.S. Navy will face in the future.

This is the second grant the ARRC team has received from the ONR this year for developing new technologies that will advance the U.S. Navy’s mission. For more information, contact Yeary at yeary@ou.edu or visit the ARRC website at https://arrc.ou.edu.

Source : University of Oklahoma

Researchers Develop Radar Simulator to Characterize Scattering of Debris in Tornadoes

Researchers have developed the first numerical polarimetric radar simulator to study and characterize the scattering of debris particles in tornadoes. (See video)

The results of their study are published in the Institute of Electrical and Electronics Engineers (IEEE) journal Transactions on Geoscience and Remote Sensing.

“These results are important for operational weather forecasters and emergency managers,” says Nick Anderson, program director in the National Science Foundation’s (NSF) Division of Atmospheric and Geospace Sciences, which funded the research. “An improved understanding of what weather radars tell us about tornado debris can help provide more accurate tornado warnings and quickly direct emergency personnel to affected areas.”

Current polarimetric radars, also called dual-polarization radars, transmit radio wave pulses horizontally and vertically. The pulses measure the horizontal and vertical dimensions of precipitation particles.

The radars provide estimates of rain and snow rates, accurate identification of the regions where rain transitions to snow during winter storms, and detection of large hail in summer thunderstorms.

But polarimetric radars have limitations the new research aims to address.

“With this simulator, we can explain in great detail to the operational weather community [weather forecasters] the tornadic echo from polarimetric radar,” says Robert Palmer, an atmospheric scientist at the University of Oklahoma (OU) and co-author of the paper. Palmer is also director of the university’s Advanced Radar Research Center. “The knowledge gained from this study will improve tornado detection and near real-time damage estimates.”

Characterizing debris fields in tornadoes is vital, scientists say, because flying debris causes most tornado fatalities.

The researchers conducted controlled measurements of tornado debris to determine the scattering characteristics of several debris types, such as leaves, shingles and boards. The orientation of the debris, the scientists found, makes a difference in how it scatters and falls through the atmosphere — and where it lands.

Additional co-authors of the paper include OU’s David Bodine, Boon Leng Cheong (lead author), Caleb Fulton, Sebastian Torres, and Takashi Maruyama of the Disaster Prevention Research Institute at Japan‘s Kyoto University.

The paper’s co-authors designed the field experiments in collaboration with atmospheric scientist Howard Bluestein of OU.

Supercomputer Simulations Help Develop New Approach to Fight Antibiotic Resistance

Supercomputer simulations at the Department of Energy’s Oak Ridge National Laboratory have played a key role in discovering a new class of drug candidates that hold promise to combat antibiotic resistance. In a study led by the University of Oklahoma with ORNL, the University of Tennessee and Saint Louis University, lab experiments were combined with supercomputer modeling to identify molecules that boost antibiotics’ effect on disease-causing bacteria.

The researchers found four new chemicals that seek out and disrupt bacterial proteins called “efflux pumps,” known to be a major cause of antibiotic resistance. Although some antibiotics can permeate the protective barriers surrounding bacterial cells, many bacteria have evolved efflux pumps that expel antibiotics back out of the cell and render the medications ineffective.

The team focused on one efflux pump protein, known as AcrA, which connects two other proteins in a tunnel shape through the bacterial cell envelope. Disrupting this centrally positioned protein could “throw a wrench” into the middle of the efflux pump and mechanically break it, unlike drug design strategies that try to inhibit overall biochemical processes.

“As a first in this field, we proposed the approach of essentially ‘screwing up’ the efflux pump’s protein assembly, and this led to the discovery of molecules with a new type of antibacterial activity,” said co-author Jeremy Smith, who serves as a UTORNL Governor’s Chair and director of the UT–ORNL Center for Molecular Biophysics. “In contrast to previous approaches, our new mechanism uses mechanics to revive existing antibiotics’ ability to fight infection.” Details of the study were published in ACS Infectious Diseases.

Through laboratory experiments done in tandem with extensive protein simulations run on ORNL’s Titan supercomputer, they scanned large numbers of chemicals to predict and select which would be the most effective in preventing AcrA proteins from assembling properly.

“The supercomputing power of Titan allowed us to perform large-scale simulations of the drug targets and to screen many potential compounds quickly,” said Helen Zgurskaya, head of OU’s Antibiotic Discovery and Resistance Group, who led the study. “The information we received was combined with our experiments to select molecules that were found to work well, and this should drastically reduce the time needed to move from the experimental phase to clinical trials.”

Using computational models, researchers screened various combinations of molecules and proteins to determine which ones “fit” well together, similar to finding the right key for a specific lock. This process was complicated by the protein’s dynamic nature; proteins constantly change their shape. In a simulated environment, researchers created virtual representations of the proteins, generated a series of protein “snapshots” in their various configurations and used Titan to “dock” thousands of molecules to each snapshot and estimate how strongly each would interact with the protein.

“The first screening took only 20 minutes using 42,000 processors and yielded several promising results,” ORNL’s Jerry Parks said. “After more extensive analysis, we narrowed down our list to predict which molecules were most likely to disrupt the function of the efflux pump.”
The research team members at the University of Oklahoma then conducted laboratory experiments to confirm the disruption of the efflux pump and the antibiotic-reviving capability for four of the molecules selected. Saint Louis University researchers then synthesized structural analogs of the discovered efflux pump inhibitors and identified properties essential for their activities.

The team’s study focused on a prototypical type of efflux pump found in Escherichia colibacteria, but the researchers anticipate that their antibiotic-reviving approach will be applicable to many Gram-negative bacteria. They plan to leverage a recently awarded Innovative and Novel Computational Impact on Theory and Experiment (INCITE) allocation from DOE to perform larger simulations on the Titan supercomputer to gain deeper understanding of how bacterial efflux pumps function, identify more potent efflux pump inhibitors and optimize the best antibiotic-plus-inhibitor combinations to make them suitable for clinical trials.

The study titled, “Reviving Antibiotics: Efflux Pump Inhibitors That Interact with AcrA, a Membrane Fusion Protein of the AcrAB-TolC Multidrug Efflux Pump,” was led by OU’s Helen Zgurskaya and co-authored by UT-ORNL’s Jeremy Smith, Jerry Parks and Jerome Baudry; UT’s Adam Green; OU’s Narges Abdali, Julie Chaney, David Wolloscheck and Valentin Rybenkov; and SLU’s Keith Haynes and John Walker. The research was supported by a National Institutes of Health grant.

The Titan supercomputer is part of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility.

UT-Battelle manages ORNL for DOE’s Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visithttp://science.energy.gov/.

OU Researchers Develop Novel, Non-Invasive Cancer Therapy Using Targeted Single-Walled Carbon Nanotubes

A staggering 1.7 million persons in the United States will be diagnosed with cancer in 2016, with 600,000 cases ending in death.  University of Oklahoma researchers have collaborated to design a novel, non-invasive cancer therapy that could eliminate tumors without affecting the healthy cells in the body.

The cancer therapy targets specific cancer cells using single-walled carbon nanotubes that bind directly to the tumor, then are heated with near-infrared light.  The OU photothermal therapy is most effective against shallow or surface tumors in breast, bladder, esophageal and melanoma cancers, without the adverse side effects of chemotherapy, radiation or surgery.

The therapy was created by Roger G. Harrison, Jr. and Daniel E. Resasco, professors in the School of Chemical, Biological and Materials Engineering, Gallogly College of Engineering. Harrison is also affiliated with the Stephenson School of Biomedical Engineering.  Harrison’s expertise is protein design, production and purification, while Resasco focuses on nanostructured materials based on single-walled carbon nanotubes.

“Single-walled carbon nanotubes are unique in that they strongly absorb near-infrared light in very narrow, but tunable, wavelength ranges, while biological systems have very low levels of absorption of near-infrared light,” said Harrison.  “The targeting of single-walled carbon nanotubes to tumors and subsequent localized application of near-infrared light allows the selective elimination of tumors.”

“Very few groups around the world are able to synthesize nanotubes which absorb light in a narrow range of wavelength,” said Resasco.  “We have a unique method of synthesis that produces single-wall nanotubes with a narrow distribution of diameters and carbon atom arrangements, which causes this selective light absorption in the near-infrared spectrum.”

The new OU photothermal therapy consists of single-walled carbon nanotubes of tailored absorption wavelength injected into the blood stream where proteins on the nanotubes selectively bind to blood vessels that supply a tumor.  Within 24 hours, a laser light is applied to the tumor causing the nanotubes to heat up, which causes the tumor to heat and be eliminated.  The photothermal therapy has been tested and proven in the laboratory.

The OU researchers already have one U.S. patent for this technology, and a second patent is nearing issuance.  The OU Office of Technology Development and the inventors are actively seeking licensees for this novel therapy to move to clinical trials.  For more information about this cancer therapy, contact Andrew Pollock, director of Business Development, at arpollock@ou.edu.