A5079248597- Electron Spin Resonance Studies
- Photosynthetic Processes and Mechanisms
- Advanced NMR Techniques and Applications
- Lanthanide and Transition Metal Complexes
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Solid-state spectroscopy and crystallography
- Magnetism in coordination complexes
- Metal-Catalyzed Oxygenation Mechanisms
- Electrochemical Analysis and Applications
- Advanced MRI Techniques and Applications
- Free Radicals and Antioxidants
- NMR spectroscopy and applications
- Molecular Junctions and Nanostructures
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Porphyrin and Phthalocyanine Chemistry
- Conducting polymers and applications
- Antioxidant Activity and Oxidative Stress
- Glass properties and applications
- Quantum and electron transport phenomena
- Organic and Molecular Conductors Research
- ATP Synthase and ATPases Research
- Advanced Chemical Physics Studies
- Molecular spectroscopy and chirality
University of Alabama
2016-2025
University of Tennessee at Knoxville
2025
Institute of Chemical Kinetics and Combustion
1979-2024
Colorado School of Mines
2023-2024
Novosibirsk Institute of Organic Chemistry
2018-2022
Siberian Branch of the Russian Academy of Sciences
2004-2022
Sanofi (United States)
2022
Inflammation Research Foundation
2022
Tuscaloosa City Schools
2016-2020
International Tomography Center
2020
Pulsed, Fourier-transform, and continuous-wave electron paramagnetic resonance methods are used to study the g=2.0319 EPR signal in synthetic diamond crystals. This is from Ni which found be located at a substitutional site lattice without detectable nearby charge compensation. The effective spin state of S=(3/2 determined Fourier-transform nutational spectroscopy. It proposed that center ${\mathrm{Ni}}^{\mathrm{\ensuremath{-}}}$ ion with electronic configuration 3${\mathit{d}}^{7}$.
We have investigated the relationship between different types and amounts of bulk defects surface morphology TiO2(110) single crystals prepared by annealing in ultrahigh vacuum oxygen. Rutile specimens were cut from same crystal heated a furnace to temperatures which resulted states reduction (colors crystals). After characterization with electron paramagnetic resonance (EPR), studied scanning tunneling microscopy (STM), low-energy He+ ion scattering (LEIS), work function measurements. EPR...
We report the development of a novel radio frequency electron-spin-resonance spectrometer designed to provide measurements with high molar sensitivity and resolution in vivo. Radio (250 MHz) is chosen obtain good penetration animal tissue large aqueous samples modest sacrifice sensitivity. The has lumped component resonator operates continuous-wave mode. capable two-dimensional imaging, addition should be three-dimensional imaging. demonstrate 3-mm spatial for DPPH samples. For 10-mℓ...
The cytochrome bc1 and related complexes are essential energy-conserving components of mitochondrial bacterial electron transport chains. They orchestrate a complex sequence proton transfer reactions resulting in the oxidation quinol, reduction mobile carrier, translocation protons across membrane to store energy an electrochemical gradient. enzyme can also catalyze substantial rates superoxide production, with deleterious physiological consequences. Progress on understanding these processes...
Water oxidation can lead to a sustainable source of energy, but for water catalysts be economical they must use earth abundant metals. We report here 2:1 6,6′-dihydroxybipyridine (6,6′-dhbp)/copper complexes that are capable electrocatalytic in aqueous base (pH = 10–14). Two crystal structures the complex contains 6,6′-dhbp and copper(II) ratio (complex 1) presented at different protonation states. The thermodynamic acid dissociation constants were measured 1, these show is fully...
A conjugated polymer semiconductor was synthesized, which exhibits a high-spin ground state and robust stability.
Here we report the synthesis of a series new nanocrystalline TiO2-(MoO3) core−shell materials whose photoabsorption energy (PE, required to excite TiO2-core valence band electrons MoO3-shell conduction states) properties are correlated with both nanoparticle size and degree chemical interaction between TiO2 core MoO3 shell. The can be readily adjusted from 80 40 Å, in this series, PE decreases 2.88 2.60 eV decreasing particle size. systematic red-shift exhibited by is ascribed change...
Although several X-ray structures have been determined for the mitochondrial cytochrome (cyt) bc1 complex, none yet shows position of substrate, ubiquinol, in quinol oxidase (Qo) site. In this study, interaction molecular oxygen with reactive intermediate Qo semiquinone is used to probe It has known some time that partial turnover cyt complex presence antimycin A, a Qi site inhibitor, results accumulation at site, which can reduce O2 superoxide (O2•-). was more recently shown myxothiazol,...
Three specifically deuterated 2-methyltetrahydrofurans (MTHF) have been synthesized to delineate the proton (deuteron) arrangement and hence molecular around a trapped excess electron in γ-irradiated glassy MTHF at 77 K. The electron–deuteron anisotropic hyperfine interaction was detected by its modulation of two-pulse spin echo envelope. Comparison experimental simulated patterns shows that is located about 3.7 Å below center plane ring carbons on side opposite methyl group three or four...
Purpose Tissue oxygen (O 2 ) levels are among the most important and quantifiable stimuli to which cells tissues respond through inducible signaling pathways. Tumor O major determinants of response cancer therapy. Developing more accurate measurements images tissue partial pressure (pO ), assumes enormous practical, biological, medical importance. Methods We present a fundamentally new technique image pO in tumors with pulse electron paramagnetic resonance (EPR) imaging enabled by an...
Abstract Conductive polymers largely derive their electronic functionality from chemical doping, processes by which redox and charge‐transfer reactions form mobile carriers. While decades of research have demonstrated fundamentally new technologies that merge the unique these materials with versatility macromolecules, doping resultant material properties are not ideal for many applications. Here, it is open‐shell conjugated comprised alternating cyclopentadithiophene thiadiazoloquinoxaline...
Pulsed Dipolar Spectroscopy (PDS) methods of Electron Paramagnetic Resonance (EPR) were used to detect and characterize reversible non-covalent dimers Human Serum Albumin (HSA), the most abundant protein in human plasma. The spin labels, MTSL OX063, attached Cys-34 these chemical modifications did affect dimerization HSA, indicating that other post-translational can modulate dimer formation. At physiologically relevant concentrations, HSA does form weak, with a well-defined structure. Dimer...
The Cu−ZnO/SiO2 sorbent for ultradeep adsorptive removal of H2S from the reformate streams at room temperature was prepared and tested, characterization active sites performed. Cu dopant significantly enhances desulfurization capacity ZnO/SiO2 (up to 92% utilization ZnO), maintains a high sulfur uptake upon multiple cycles 10) regeneration by simple thermal oxidation in air. “as-prepared” (“calcined”) contains Cu2+ form, O, Si, Zn as ZnO, while “spent” (“sulfided”) Cu, S, ZnS found XPS. XRD...
The results of reaction yield-detected magnetic resonance (RYDMR) experiments carried out on modified bacterial photosynthetic centers (RCs) are interpreted in terms a model that assigns the initial charge-separated radical ion-pair state, P F , as carrier spectrum. pair theory, which has been invoked to explain field effects RCs, was significantly expanded take into consideration electron dipole-dipole interaction. It is shown this largest interaction between components ion pair. Quantum...
In comparison to imidazole (IMZ) and 1,2,4-triazole (1,2,4-TRZ), the isosteric 1,2,3-triazole (1,2,3-TRZ) is unrepresented among cytochrome P450 (CYP) inhibitors. This surprising because 1,2,3-TRZs are easily obtained via "click" chemistry. To understand this underrepresentation of CYP inhibitors, thermodynamic density functional theory computational studies were performed with unsubstituted IMZ, 1,2,4-TRZ, 1,2,3-TRZ. The results indicate that lower affinity 1,2,3-TRZ for heme iron includes...
Abstract Trityl radicals (TAMs) have recently appeared as an alternative source of spin labels for measuring long distances in biological systems. Finland trityl radical (FTAM) served the basis this new generation labels, but FTAM is rather lipophilic and susceptible to self‐aggregation, noncovalent binding with sites proteins, docking at termini duplex DNA. In paper very hydrophilic OX063 TAM low toxicity little tendency aggregation used a label. Human serum albumin (HSA) labeled has...
Electron spin-lattice relaxation of two trityl radicals, d24-OX063 and Finland trityl, were studied under conditions relevant to their use in dissolution dynamic nuclear polarization (DNP). The dependence kinetics on temperature up 100 K concentration 60 mM was obtained at X- W-bands (0.35 3.5 Tesla, respectively). is quite similar both bands for radicals. At concentrations typical DNP, mediated by excitation transfer spin-diffusion fast-relaxing centers identified as triads radicals that...
The development of open-shell organic molecules that magnetically order at room temperature,which can be practically applied, remains a grand challenge in chemistry, physics, and materials science. Despite the exploration vast chemical space, design paradigms for paramagnetic centers generally result unpaired electron spins are unstable or isotropic. Here, high-spin conjugated polymer is demonstrated, which composed alternating cyclopentadithiophene benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole...