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Full-Text Articles in Physics

Alamethicin In Lipid Bilayers: Combined Use Of X-Ray Scattering And Md Simulations, Jianjun Pan, D. Peter Tieleman, John F. Nagle, Norbert Kučerka, Prof. Stephanie Tristram-Nagle Ph.D. Aug 2016

Alamethicin In Lipid Bilayers: Combined Use Of X-Ray Scattering And Md Simulations, Jianjun Pan, D. Peter Tieleman, John F. Nagle, Norbert Kučerka, Prof. Stephanie Tristram-Nagle Ph.D.

John Copeland Nagle

We study fully hydrated bilayers of two di-monounsaturated phospholipids diC18:1PC (DOPC) and diC22:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering and molecular dynamics simulations to determine the orientation of alamethicin in model lipids. Comparison of the experimental and simulated form factors shows that Alm helices are inserted transmembrane at high humidity and high concentrations, in agreement with earlier results. The X-ray scattering data and the MD simulations agree that membrane thickness changes very little up to 1/10 Alm/ DOPC. In contrast, the X-ray data indicate that the thicker diC22:1PC membrane thins with added …


Preferential Silicon Site Occupation In Y₂Fe₁₄₋ₓsiₓb, G. K. Marasinghe, Oran Allan Pringle, Gary J. Long, Fernande Grandjean, William B. Yelon Aug 2016

Preferential Silicon Site Occupation In Y₂Fe₁₄₋ₓsiₓb, G. K. Marasinghe, Oran Allan Pringle, Gary J. Long, Fernande Grandjean, William B. Yelon

Oran Pringle

No abstract provided.


Study Of Structural And Magnetic Properties Of Iron-Rich Mixed Rare-Earth Nddyfe (17-Y-X)Coxsiy Compounds, Kishore Kamaraju, Jinbo Yang, William B. Yelon, Oran Allan Pringle, M. S. Kim, Qingsheng Cai, William Joseph James Aug 2016

Study Of Structural And Magnetic Properties Of Iron-Rich Mixed Rare-Earth Nddyfe (17-Y-X)Coxsiy Compounds, Kishore Kamaraju, Jinbo Yang, William B. Yelon, Oran Allan Pringle, M. S. Kim, Qingsheng Cai, William Joseph James

Oran Pringle

A series of NdDyFe(17-y-x)CoxSiy solid solutions with = 2 and 3 and = 0.5 1.0 and 1.5 were prepared by induction melting stoichiometric amounts of high-purity elements. The postannealed samples consist of two phases belonging to the space groups R3 m and P63 mmc . The lattice parameters and the unit cell volumes were calculated from the refinements of the magnetic and structural unit cells using the FULLPROF version of the Rietveld program. For a fixed content of Co, the maximum Curie temperatures (305 C to 405 C) were observed in samples with = 1 and having two phases, a …


Magnetic And Crystallographic Properties Of Lani5-XFex, C. Tan, Oran Allan Pringle, Mingxing Chen, William B. Yelon, J. Gebhardt, Naushad Ali, C. Y. Tai, G. K. Marasinghe, George Daniel Waddill, William Joseph James Aug 2016

Magnetic And Crystallographic Properties Of Lani5-XFex, C. Tan, Oran Allan Pringle, Mingxing Chen, William B. Yelon, J. Gebhardt, Naushad Ali, C. Y. Tai, G. K. Marasinghe, George Daniel Waddill, William Joseph James

Oran Pringle

No abstract provided.


Mössbauer Effect Studies Of Nd₂Fe14-XSiXB And Y3Fe14-XSiXB, Oran Allan Pringle, Gary J. Long, G. K. Marasinghe, William Joseph James, Antoni T. Pedziwiatr, W. E. Wallace, Fernande Grandjean Aug 2016

Mössbauer Effect Studies Of Nd₂Fe14-XSiXB And Y3Fe14-XSiXB, Oran Allan Pringle, Gary J. Long, G. K. Marasinghe, William Joseph James, Antoni T. Pedziwiatr, W. E. Wallace, Fernande Grandjean

Oran Pringle

No abstract provided.


How To Establish Successful Cooperative Student Learning Centers For Stem Courses, Ronald James Bieniek, Douglas R. Carroll, Cesar Mendoza, Oran Allan Pringle, Ekkehard Sinn, Kai-Tak Wan, Donald C. Wunsch Aug 2016

How To Establish Successful Cooperative Student Learning Centers For Stem Courses, Ronald James Bieniek, Douglas R. Carroll, Cesar Mendoza, Oran Allan Pringle, Ekkehard Sinn, Kai-Tak Wan, Donald C. Wunsch

Oran Pringle

Students learn more if they are actively involved in the learning process, particularly in a cooperative manner. Several UMR faculty have operated course-based learning centers (LCs) as part of the campus-wide Learning Enhancement Across Disciplines (LEAD) Program of student learning assistance and enhancement. LCs are designed to assist large numbers of students in a cost- and time-efficient manner that promotes student engagement without requiring undue amounts of faculty time. Course instructors spend time in the open learning environment of the LC, in lieu of office hours, guiding students to master course material and skills in their evolution from novice to …


Measurement Of Spin-Flip Probabilities For Ultracold Neutrons Interacting With Nickel Phosphorus Coated Surfaces, Zhaowen Tang, Evan Robert Adamek, Aaron Brandt, Nathan Brannan Callahan, Steven M. Clayton, Scott Allister Currie, Takeyasu M. Ito, Mark F. Makela, Yasuhiro Masuda, Christopher L. Morris, Robert Wayne Pattie, John Clinton Ramsey, Daniel J. Salvat, Daniel J. Salvat, Alexander Saunders, Albert R. Young Aug 2016

Measurement Of Spin-Flip Probabilities For Ultracold Neutrons Interacting With Nickel Phosphorus Coated Surfaces, Zhaowen Tang, Evan Robert Adamek, Aaron Brandt, Nathan Brannan Callahan, Steven M. Clayton, Scott Allister Currie, Takeyasu M. Ito, Mark F. Makela, Yasuhiro Masuda, Christopher L. Morris, Robert Wayne Pattie, John Clinton Ramsey, Daniel J. Salvat, Daniel J. Salvat, Alexander Saunders, Albert R. Young

Robert W. Pattie Jr.

We report a measurement of the spin-flip probabilities for ultracold neutrons interacting with surfaces coated with nickel phosphorus. For 50 μm thick nickel phosphorus coated on stainless steel, the spin-flip probability per bounce was found to be βNiPonSS=(3.3−5.6+1.8)×10−6. For 50 μm thick nickel phosphorus coated on aluminum, the spin-flip probability per bounce was found to be βNiPonAl=(3.6−5.9+2.1)×10−6. For the copper guide used as reference, the spin flip probability per bounce was found to be βCu=(6.7−2.5+5.0)×10−6. The results on the nickel phosphorus-coated surfaces may be interpreted as upper limits, yielding βNiPonSS<6.2×10−6 (90% C.L.) and βNiPonAl<7.0×10−6 (90% C.L.) for 50 μm thick …


Developing Hyperpolarized Silicon Particles For In Vivo Mri Targeting Of Ovarian Cancer, Nicholas Whiting, Jingzhe Hu, Niki M. Zacharias, Ganesh L. R. Lokesh, David E. Volk, David G. Menter, Rajesha Rupaimoole, Rebecca Previs, Anil K. Sood, Pratip Bhattacharya Aug 2016

Developing Hyperpolarized Silicon Particles For In Vivo Mri Targeting Of Ovarian Cancer, Nicholas Whiting, Jingzhe Hu, Niki M. Zacharias, Ganesh L. R. Lokesh, David E. Volk, David G. Menter, Rajesha Rupaimoole, Rebecca Previs, Anil K. Sood, Pratip Bhattacharya

Nicholas Whiting

Silicon-based nanoparticles are ideally suited for use as biomedical imaging agents due to their biocompatibility, biodegradability, and simple surface chemistry that facilitates drug loading and targeting. A method of hyperpolarizing silicon particles using dynamic nuclear polarization, which increases magnetic resonance imaging signals by several orders-of-magnitude through enhanced nuclear spin alignment, has recently been developed to allow silicon particles to function as contrast agents for in vivo magnetic resonance imaging. The enhanced spin polarization of silicon lasts significantly longer than other hyperpolarized agents (tens of minutes, whereas <1  min for other species at room temperature), allowing a wide range of potential …


The Treatment Of Exchange In Path Integral Simulations Via An Approximate Pseudopotential, Randall W. Hall Jun 2016

The Treatment Of Exchange In Path Integral Simulations Via An Approximate Pseudopotential, Randall W. Hall

Randall W. Hall

An approximate form that includes the effects of exchange is suggested for the short time propagator used in path integral simulations. The form is inspired physically by the approximation made in Hartree–Fock treatments of atoms and molecules. The approximate propagator is used with q u a n t i t a t i v e accuracy in two systems: an ideal gas of fermions localized in a three‐dimensional harmonic well and the triplet state of the sodium dimer.


Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall Jun 2016

Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall

Randall W. Hall

Feynman’s path integral formulation of quantum mechanics is used to study the correlated electronic states of Na4–Na6. Two types of simulations are performed: in the first, the nuclei are allowed to move at finite temperature in order to find the most stable geometries. In agreement with previous calculations, we find that planar structures are the most stable and that there is significant vibrational amplitude at finite temperatures, indicating that the Born–Oppenheimer surface is relatively flat. In the second type of simulation, the nuclei are held fixed at symmetric and asymmetric geometries and the correlated electron density is found. Our results …


Interplay Between Anomalous Transport And Catalytic Reaction Kinetics In Single-File Nanoporous Systems, Dajiang Liu, Jigang Wang, David Ackerman, Igor I. Slowing, Marek Pruski, Hung-Ting Chen, Victor S.-Y. Lin, James W. Evans Mar 2016

Interplay Between Anomalous Transport And Catalytic Reaction Kinetics In Single-File Nanoporous Systems, Dajiang Liu, Jigang Wang, David Ackerman, Igor I. Slowing, Marek Pruski, Hung-Ting Chen, Victor S.-Y. Lin, James W. Evans

Jigang Wang

Functionalized nanoporous materials have broad utility for catalysis applications. However, the kinetics of catalytic reaction processes in these systems can be strongly impacted by the anomalous transport. The most extreme case corresponds to single-file diffusion for narrow pores in which species cannot pass each other. For conversion reactions with a single-file constraint, traditional mean-field-type reaction-diffusion equations fail to capture the initial evolution of concentration profiles, and they cannot describe the scaling behavior of steady-state reactivity. Hydrodynamic reaction-diffusion equations accounting for the single-file aspects of chemical diffusion can describe such initial evolution, but additional refinements are needed to incorporate fluctuation effects …


Interrogating Metabolism In Brain Cancer, Travis Salzillo, Jingzhe Hu, Linda Nguyen, Nicholas Whiting, Jaehyuk Lee, Joseph Weygand, Prasanta Dutta, Shivanand Pudakalakatti, Niki Zacharias Millward, Seth Gammon, Frederick F. Lang, Amy B. Heimberger, Pratip Bhattacharya Dec 2015

Interrogating Metabolism In Brain Cancer, Travis Salzillo, Jingzhe Hu, Linda Nguyen, Nicholas Whiting, Jaehyuk Lee, Joseph Weygand, Prasanta Dutta, Shivanand Pudakalakatti, Niki Zacharias Millward, Seth Gammon, Frederick F. Lang, Amy B. Heimberger, Pratip Bhattacharya

Nicholas Whiting

Many existing and emerging techniques of interrogating metabolism in brain cancer are at an early stage of development. A few clinical trials that employ these techniques are in progress in patients with brain cancer to establish the clinical efficacy of these techniques. It is likely that in vivo metabolomics and metabolic imaging is the next frontier in brain cancer diagnosis and assessing therapeutic efficacy.