Physical Sciences and Mathematics Commons^™

Macrocyclic Antibiotics As Separation Agents, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Macrocyclic antibiotics having ring structures with at least 10 members act as separation agents in crystallization, precipitation, filtration, electrophoresis, and chromatography. The macrocyclic antibiotics include ansamacrolides, macrolides, macrocyclic peptides, polyenes and derivatives thereof. The process has been found to be especially advantageous for separation of optical isomers by electrophoresis and chromatography.

Melanoma And Seborrheic Keratosis Differentiation Using Texture Features, Srinivas V. Deshabhoina, Scott E. Umbaugh, William V. Stoecker, Randy Hays Moss, Subhashini K. Srinivasan

Chemistry Faculty Research & Creative Works

Purpose: To explore texture features in two-dimensional images to differentiate seborrheic keratosis from melanoma.

Methods: A systematic approach to consistent classification of skin tumors is described. Texture features, based on the second-order histogram, were used to identify the features or a combination of features that could consistently differentiate a malignant skin tumor (melanoma) from a benign one (seborrheic keratosis). Two hundred and seventy-one skin tumor images were separated into training and test sets for accuracy and consistency. Automatic induction was applied to generate classification rules. Data analysis and modeling tools were used to gain further insight into the feature space. …

Study Of The Electronic Properties Of Some Ytterbium Filled Skutterudites By Magnetic Susceptibility And X-Ray Absorption And Tin-119 Mössbauer Spectroscopy, Fernande Grandjean, Gary J. Long, Bernard M. Mahieu, Ji Hui Yang, Gregory P. Meisner, Donald T. Morelli

Chemistry Faculty Research & Creative Works

Magnetic susceptibility, ytterbium L_III-edge x-ray absorption and tin-119 Mössbauer spectral measurements have been carried out to probe the electronic structure of ytterbium and tin in the filled or partially filled skutterudite compounds, Yb_yCo₄Sb_12-xSn_x, over a range of x and y values. The ytterbium valence obtained from the magnetic susceptibility and ytterbium L_III-edge x-ray absorption measurements is in excellent agreement and clearly reveals an evolution from intermediate valence ytterbium for x=0 to nearly divalent ytterbium for x=0.8. This evolution parallels an increase in the unit cell volume and hence …

Single-Walled Carbon Nanotube Bundles Intercalated With Semiconductor Nanoparticles, Manashi Nath, Pallavi V. Teredesai, D. V. S. Muthu, A. K. Sood, Chintamani Nagesa Ramachandra Rao

Chemistry Faculty Research & Creative Works

Nanoparticles of CdSe, CdS and ZnSe have been incorporated in the inter-tubular gaps of single-walled carbon nanotube (SWNT) bundles. Electron microscope, X-ray diffraction (XRD), electronic spectroscopy and Raman studies have been employed to characterize these systems. The lengths of the intercalate inside the bundles could be varied by changing the reaction conditions. Electronic absorption and photoluminescence studies from the semiconductor intercalates show the expected blue-shift with respect to the corresponding bulk samples in CdS and ZnS samples. The SWNT lattice is expanded on incorporating CdSe as confirmed by XRD in the low-angle range. The expansion in the lattice is also …

One-Step Processing Of Spinel Ferrites Via The High-Energy Ball Milling Of Binary Oxides, V. G. Harris, D. J. Fatemi, J. O. Cross, E. E. Carpenter, V. M. Browning, J. P. Kirkland, Amitabh Mohan, Gary J. Long

Chemistry Faculty Research & Creative Works

MnZn ferrites have been produced via the high-energy ball milling of binary oxide precursors. The milled ferrites have a nonequilibrium cation site distribution, with an unusually high population of Zn cations on the octahedral sites. The particle size distribution drops precipitously with milling time from 60±1 to ∼14±1 nm at 10 h, but increases to 18.5±1 nm after long durations (20–40 h) concurrent with the formation of nearly pure ferrite. A 1 h anneal at 673 K facilitates a redistribution of cations to their near equilibrium sites. This processing approach circumvents the need for deleterious high-temperature heat treatments that often …

Solvent And Method For Extraction Of Triglyceride Rich Oil, Shubhender Kapila, Paul Ki-Souk Nam, V. J. Flanigan

Chemistry Faculty Research & Creative Works

The present invention relates to a solvent for use in extracting oil from an oil bearing material, such as soybeans, with the solvent resulting in the selective extraction of a triglyceride rich oil, which contains 95% or greater triglycerides and non-polar constituents, with the solvent comprised of a hydrocarbon, preferably hexane, and a fluorocarbon, so that the solvent has a viscosity less than 2.6 centipoise and a polarity of less than 0.1. The present invention also relates to a method of using the solvent to extract the triglyceride rich oil, with the method including preferably extracting the oil at a …

Properties Of A Mixed-Valent Iron Compound With The Kagomé Lattice, Chintamani Nagesa Ramachandra Rao, Geo L. Paul, Amitava Choudhury, Echur Varadadesikan Sampathkumaran, Arup Kumar R. Raychaudhuri, Suryanarayanasastry Ramasesha, Indranil Rudra

Chemistry Faculty Research & Creative Works

An organically templated iron sulfate of the formula [HN(CH₂)₆NH][Fe^III Fe₂ ^IIF₆(SO₄)₂] ·[H₃O] possessing the kagomé lattice has been prepared and characterized by single-crystal crystallography and other techniques. This mixed-valent iron compound shows complex magnetic properties including spin-glass behavior and magnetic hysteresis. The low-temperature specific heat data show deviation from the T² behavior found in two-dimensional frustrated systems. Simple calculations have been carried out to understand the properties of this kagomé compound.

Einstein Oscillators In Thallium Filled Antimony Skutterudites, Raphaël P. Hermann, Rongying Jin, Werner Schweika, Fernande Grandjean, David G. Mandrus, Brian C. Sales, Gary J. Long

Chemistry Faculty Research & Creative Works

Heat capacity measurements were performed on Tl_0.8Co₄Sb₁₁Sn. An Einstein vibrating behavior for the thallium atoms was found. The inelastic neutron scattering measurements on T_0.8Co₄Sb₁₁Sn, Tl_0.5Co_3.5Fe_0.5Sb₁₂, and Tl_0.8Co₃FeSb₁₂ showed a localized vibrational mode, which confirmed this Einstein vibrational behavior. Furthermore, the 56±2 K temperature of the Einstein vibrational mode obtained from the heat capacity measurements showed excellent agreement with the 5 meV energy or 57±2 K values obtained from the neutron scattering measurements.

Magnetic And Mössbauer Spectral Study Of Erfe₁₁Ti And Erfe₁₁Tih, Cristina Piquer, Raphäel P. Hermann, Fernande Grandjean, Gary J. Long, Olivier Isnard

Chemistry Faculty Research & Creative Works

The influence of the insertion of hydrogen into the crystal lattice of ErFe₁₁Ti upon its spin reorientation was investigated. It was found that the insertion of hydrogen into ErFe₁₁Ti to form ErFe₁₁TiH expanded the lattice by 1% and increased the Curie temperature by 56 K. The presence of one titanium near neighbor in the environment of an iron site decreased the hyperfine field by ~2T and changed the isomer shift by ~0.05 mm/s.

Dynamics Of Adsorbed Poly(Methyl Acrylate) And Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Wuu-Yung Lin, Crystal E. Porter

Chemistry Faculty Research & Creative Works

Deuterium NMR and modulated differential scanning calorimetry (MDSC) were used to probe the behavior of ultrathin adsorbed poly(methyl acrylate) (PMA). The spectra for the bulk methyl-labeled PMA-d3 were consistent with the motions of the polymer segments being spatially homogeneous. For the polymers adsorbed on silica, multicomponent line shapes were observed. The segmental mobility of the surface polymers increased with increased adsorbed amounts. In contrast to the behavior of the polymers in bulk, the adsorbed lower-molecular-mass PMA-d3 was less mobile than the adsorbed high-molecular-mass polymer. The presence of a polymer overlayer was sufficient to suppress the enhanced mobility of the more-mobile …

Dynamics Of Bulk And Adsorbed Poly(Vinyl Acetate), Frank D. Blum, Robert D. O'Connor

Materials Science and Engineering Faculty Research & Creative Works

We have recently completed a series of experiments on methyl-labeled poly(vinyl acetate)-d3, (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3).234 the systems have been studied as a function of the adsorbed amount, molecular weight, and presence of a protonated overlayer. Using deuterium line shape analysis, we have found that around the glass transition temperature, the adsorbed polymers show the presence of a motional gradient. Polymer segments near the silica-polymer interface have less mobility than the bulk polymer and those near the polymer-air interface are more mobile than those of the bulk polymer. A schematic representation of the motional gradient is shown in Figure …

A Hmm Based Semantic Analysis Framework For Sports Game Event Detection, Gu Xu, Yu-Fei Ma, Hong-Jiang Zhang, Shiqiang Yang

Chemistry Faculty Research & Creative Works

Video events detection or recognition is one of important tasks in semantic understanding of video content. Sports game video should be considered as a rule-based sequential signal. Therefore, it is reasonable to model sports events using hidden Markov models. In this paper, we present a generic, scalable and multilayer framework based on HMMs, called SG-HMMs (sports game HMMs), for sports game event detection. At the bottom layer of this framework, event HMMs output basic hypotheses based on low-level features. The upper layers are composed of composition HMMs, which add constraints on those hypotheses of the lower layer. Instead of isolated …

Deuterium Nmr Studies Of Bulk And Silica-Absorbed Polystyrene, Macduff O. Okuom, Jinhua Yang, Frank D. Blum

Chemistry Faculty Research & Creative Works

Thin polymer films are used in applications such as electronics, biomedical devices and coatings. As the trend to make the devices smaller continues, a film's influence on a material's overall properties becomes more prominent. Previous studies have shown that thin polymer films have characteristics slightly different from those of bulk polymers. Film behavior has been characterized by examining thermal expansion, diffusion, conformation, density and glass transitions. The dynamics of glassy polystyrene has been investigated using a wide variety of theoretical and experimental methods. Schaefer et al., using 13C NMR, reported that ~7% of phenyl rings in polystyrene undergo -flips. Using …

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

Physics Faculty Research & Creative Works

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 …

Molecular Mass And Dynamics In Pma-D₃ In The Glass Transition Region, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The segmental dynamics through the glass transition region, by which the glassy polymer becomes rubbery, are not well understood. Free volume, thermodynamic and kinetic theories have been used to describe the phenomenon behind the glass transition and some of those theories were tested with computer simulations. Different experimental techniques, such as NMR, thermo-mechanical analysis (TMA), differential scanning calorimetry (DSC), dilatometry and dynamic mechanical analysis (DMA) have all been also used to probe this important phenomena. Deuterium (2H) NMR has been a valuable tool for the investigation of the dynamics of macromolecules. Deuteration of macromolecules at specific locations on the chains …

Ft-Ir Studies Of Stereo Regular Pmma On Silica: Drying Effects, Bing Zhang, Suntree Kulkeratiyut, Suriyaphongse Kulkeratiyut, Frank D. Blum

Chemistry Faculty Research & Creative Works

A great amount of work has been done on the configuration of surface adsorbed poly(methyl methacrylate) (PMMA), especially on surfaces to which they have a strong attraction. Some studies have been make on the relationships between configuration and tacticity, molecular weight, adsorbed amount, and density of surface hydroxyl groups. The effect of tacticity on the conformation of alumina-adsorbed PMMA in solution and dry spin-coated films were studied by Grohen et al. Their results showed that surface-adsorbed PMMA chains adopted a relatively flat configuration, but iso-PMMA (isotactic) adsorbed on aluminum, with a much larger fraction of the bound carbonyl groups, had …