A5060800875- Advanced NMR Techniques and Applications
- Solid-state spectroscopy and crystallography
- NMR spectroscopy and applications
- Advanced Battery Materials and Technologies
- Fuel Cells and Related Materials
- Muon and positron interactions and applications
- Lipid Membrane Structure and Behavior
- Electron Spin Resonance Studies
- Antimicrobial Peptides and Activities
- Membrane Separation Technologies
- Membrane-based Ion Separation Techniques
- Atomic and Subatomic Physics Research
- Molecular spectroscopy and chirality
- Conducting polymers and applications
- Zeolite Catalysis and Synthesis
- Organic Electronics and Photovoltaics
- Cellular transport and secretion
- Radioactive element chemistry and processing
- Parkinson's Disease Mechanisms and Treatments
- Extraction and Separation Processes
- Alzheimer's disease research and treatments
- Synthesis and Properties of Aromatic Compounds
- Biofuel production and bioconversion
- Amyloidosis: Diagnosis, Treatment, Outcomes
- Synthesis and properties of polymers
National High Magnetic Field Laboratory
2015-2025
Florida State University
2014-2024
Tallahassee Orthopedic Clinic
2019
Weizmann Institute of Science
2001-2015
University of Windsor
2015
Virginia Tech
2006-2014
Iowa State University
2004-2005
University of Illinois Urbana-Champaign
2005
University of California, Los Angeles
2004
University of California, Berkeley
2003
Abstract The switchgrass (SG) samples pretreated by cellulose solvent‐ and organic solvent‐based lignocellulose fractionation were characterized enzymatic hydrolysis, substrate accessibility assay, scanning electron microscopy, X‐ray diffraction (XRD), cross polarization/magic angle spinning (CP/MAS) 13 C nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR). Glucan digestibility of the SG was 89% at hour 36 one filter paper unit cellulase per gram glucan....
Water-soluble derivatives of gadolinium-containing metallofullerenes have been considered to be excellent candidates for new magnetic resonance imaging (MRI) contrast agents because their high relaxivity and characteristic encapsulation the lanthanide ions (Gd3+), preventing release into bioenvironment. The trimetallic nitride template endohedral (TNT EMFs) further advantages stability, relative yield, three Gd3+ per molecule as illustrated by previously reported nearly spherical,...
An increasing body of evidence suggests that aggregation-prone proteins associated with various neurodegenerative diseases synergistically promote their mutual aggregation, leading to the co-occurrence multiple in same patient. Here we investigated teh molecular basis synergistic interactions between two pathological proteins, tau and α-synuclein, using biophysical techniques including transmission electron microscopy (TEM), circular dichroism (CD), solution solid-state NMR. Our analyses...
Fourier self-deconvolution (FSD) was performed on protein amide I and II transform infrared (FTIR) spectra to test if the resultant increased band shape variation would lead improvements in secondary structure prediction with our factor analysis based restricted multiple regression (RMR) methods. FTIR of 23 proteins dissolved H2O were measured normalized a constant peak absorbance. The deconvolved renormalized by area so that sets had same as before. Principal component carried out, which...
Multinuclear solid-state nuclear magnetic resonance studies (185/187Re, 55Mn, 75As, and 1H NMR) were undertaken on a series of polycrystalline inorganic salts incorporating diamagnetic XO4- groups, X being half-integer quadrupolar nucleus. Exploiting data acquisition protocols that recently developed for observing undistorted quadrupole central transitions, some the largest coupling constants reported to date by high field NMR characterized (e2qQ/h ≈ 300 MHz). On repeating such measurements...
Abstract Characterization of small oligomers formed at an early stage amyloid formation is critical to understanding molecular mechanism pathogenic aggregation process. Here we identified and characterized cytotoxic oligomeric intermediates populated during transthyretin (TTR) Under the amyloid-forming conditions, TTR initially forms a dimer through interactions between outer strands. The dimers are then associated form hexamer with spherical shape, which serves as building block...
Membrane pores that are induced in oriented membranes by an antimicrobial peptide (AMP), protegrin-1 (PG-1), investigated 31P and 2H solid state NMR spectroscopy. We incorporated a well-studied peptide, β-sheet AMP, to investigate AMP-induced dynamic supramolecular lipid assemblies at different concentrations membrane compositions. Anisotropic line shapes specifying toroidal thinned membranes, which formed bilayers the binding of AMPs, have been analyzed for first time. Theoretical lipids...
A new class of organic ionic plastic crystals was discovered. series alkylene 1,2-bis[N-(N′-alkylimidazolium)] salts with Br− and PF6− anions prepared most the ethylene (C2) linked compounds undergo multiple solid–solid phase transitions as determined by differential scanning calorimetry (DSC). The longer spacers (C3 or C4) between imidazolium units do not display any transitions. terminal C10 C12n-alkyl moieties are "classical" Timmermans' definition; they have low ΔSf (11 J K−1 mol−1 for...
Nonsecular dipolar couplings between spin-12 nuclei that are in close proximity to quadrupolar spins have been extensively documented solid state nuclear magnetic resonance (NMR), particularly when involving directly bonded S=13C, I=14N spin pairs. These arise due the quadrupole-induced tilting of I’s quantization axes, and their most notable characteristic is they cannot be entirely averaged away by conventional magic-angle-spinning (MAS). can also expected both I S nuclei, even if these...
RTD-1 is a cyclic β-hairpin antimicrobial peptide isolated from rhesus macaque leukocytes. Using 31P, 2H, 13C, and 15N solid-state NMR, we investigated the interaction of with lipid bilayers different compositions. 31P 2H NMR uniaxially oriented membranes provided valuable information about how affects static dynamic disorder bilayer. Toward phosphatidylcholine (PC) bilayers, causes moderate orientational independent bilayer thickness, suggesting that binds to surface PC without perturbing...
Fungal infections cause high mortality in immunocompromised individuals, which has emerged as a significant threat to human health. The efforts devoted the development of antifungal agents targeting cell wall polysaccharides have been hindered by our incomplete picture assembly and remodeling fungal walls. High-resolution solid-state nuclear magnetic resonance (ss NMR) studies substantially revised understanding polymorphic structure nanoscale organization walls Aspergillus fumigatus...
The interactions between glycosaminoglycans (GAGs) and proteins are essential in numerous biochemical processes that involve ion-pair interactions. However, there is no evidence of direct specific GAGs collagen native cartilage. resolution solid-state NMR (ssNMR) can offer such information but the detection GAG cartilage limited by sensitivity experiments when
Here we present fundamental studies of a new blending strategy for enhancing water permeability in ionomeric reverse osmosis membrane materials. A random disulfonated poly(arylene ether sulfone) copolymer containing 20 mol percent hydrophilic units (BPS-20) the potassium salt (−SO3K) form was blended with hydroxyl-terminated poly(ethylene glycol) oligomers (PEG, Mn= 600−2 000) to increase BPS-20. Blending PEG resulted pseudoimmobilization BPS-20 polymer chains because complexes cations...
Dynamic Nuclear Polarization (DNP) can increase the sensitivity of Magnetic Resonance (NMR), but it is challenging in liquid state at high magnetic fields. In this study we demonstrate significant enhancements NMR signals (up to 70 on 13C) by scalar Overhauser DNP 14.1 T, with resolution (∼0.1 ppm) and relatively large sample volume (∼100 μL).
Investigations were made of rotary resonance recouplings (R3) chemical shift anisotropy (CSA), heteronuclear dipolar (HTD), and homonuclear (HMD) couplings involving half-integer quadrupolar nuclei under magic-angle sample spinning condition. Under conditions provided by a low amplitude rf field high speed, the spectrum central transition coherence shows CSA, HTD, HMD interactions that depend on ratio to speed. These new properties can be used extract electronic structural information about...
A new NMR technique for determining long-range 1H-19F distances in solids is demonstrated. Using a modified rotational-echo double resonance (REDOR) sequence involving 1H homonuclear decoupling and composite 19F pulses, we show that it possible to determine approximately 8 A. The detrimental effect of the large chemical shift REDOR dephasing partially compensated by pulse, 90 degrees 225 315 . 1HNLeu-19FPhe distance peptide f-MLF-OH was found be 7.7 This used refine Phe side chain...
A series of poly(arylene ether sulfone) copolymers containing the diazocine unit (0, 20, 50, 80, 100 mol %) were synthesized via step-growth polymerization. Copolymer compositions exhibited number-average molecular weights exceeding 30 000 g/mol, and mechanically ductile films obtained for all compositions. The random enhanced thermal stability (Td10% = 500−550 °C) mechanical properties (tensile stress 45−65 MPa), thermomechanical performance was predictable based on copolymer composition....
Membranes for gas separations are limited by the trade-off relationship between permeability and selectivity. In this study, we demonstrate an in situ thermal oxidative crosslinking strategy amine-functionalized polymers using tert-butoxycarbonyl (tBOC) groups to improve separation performance. The use of labile tBOC offers two major benefits inducing crosslinks: (1) they trigger free radical chain reactions at more moderate temperatures, preventing polymer backbone degradation pathways that...