EPR Center Research

Research interests of the Eaton group encompass instrument development for biomedical applications of electron paramagnetic resonance. Current focus areas include:

  • Development of a rapid scan imager operating at 1 GHz for in vivo measurement of local oxygen concentration and redox status.
  • Design and characterization of nitroxide spin labels that have sufficiently long relaxation times at room temperature to permit spin-spin distance measurements.
  • Understanding of electron spin relaxation times as a function of temperature to develop models that will permit design of species for applications in biological systems and materials science.

Most of Sandra and Gareth Eaton’s publications from the past 10 years are listed in the NIH-supported Pubmed data base:

Student Research

Research in our group involves collaboration between chemists, biochemists, and engineers. The dissertations of recent graduates provide insights into the work that is ongoing in the EPR center:

Whylder Moore was an MS student in the Department of Chemistry and Biochemistry. The focus of his work was the electron spin relaxation times for triarylmethyl (trityl) radicals and diradicals that contain a trityl and a nitroxide. His thesis entitled "EPR Relaxation of Modified Triphenylmethyl and Nitroxide Radicals" (2021) is available through DU's digital commons.

Joseph E. McPeak was a PhD student in the Department of Chemistry and Biochemistry. He was a key contributor to the development of rapid scan experiments for radicals with highly-resolved spectra and rapid scan of wide spectra at low temperatures. His dissertation, entitled "Instrument and Application Development in Saturation Recovery and Rapid Scan Electron Paramagnetic Resonance" (2020), is available through DU’s digital commons.

Yilin Shi was a PhD student in the Department of Chemistry and Biochemistry. She was a key contributor to the development of rapid-scan imaging at 250 MHz and 700 MHz. Her dissertation, entitled "Rapid-Scan EPR and Imaging" (2019), is available through DU’s digital commons.

Laura A. Buchanan was a PhD student in the interdisciplinary Molecular and Cellular Biophysics Program. She was a key contributor to the development and testing of our 700 MHz and 1 GHz (L-band) systems. Her dissertation, entitled "Development of Low Frequency Electron Paramagnetic Resonance Methods and Instrumentation for Biological Applications" (2018), is available through DU’s digital commons.

Additional Publications

  • Relaxation Time Publications

    Review Articles

    Relaxation Mechanisms, S. S. Eaton and G. R. Eaton, EPR Spectroscopy: Fundamentals and Methods, D. Goldfarb and S. Stoll, eds., John Wiley & Sons, 175 – 192 (2018).

    Multifrequency Pulsed EPR and the Characterization of Molecular Dynamics. S. S. Eaton and G. R. Eaton, in P. Qin and K. Warncke, eds, Electron Paramagnetic Resonance Investigations of Biological Systems by Using Spin Labels, Spin Probes, and Intrinsic Metal Ions, Part A, Methods in Enzymology 563, Academic Press, UK, pp. 37-58 (2015).

    Frequency Dependence of Electron Spin Relaxation Times, G. R. Eaton and S. S. Eaton, in Multifrequency Electron Paramagnetic Resonance: Theory and Applications, S. K. Misra, Ed., ch. 17, Wiley-VCH, 2011.

    Relaxation Times of Organic Radicals and Transition Metal Ions, S. S. Eaton and G. R. Eaton, in Distance Measurements in Biological Systems by EPR, G. R. Eaton, S. S. Eaton, and L. J. Berliner, eds., Biol. Magn. Reson. 19, 29-154 (2000).

    Electron Spin Lattice Relaxation Rates for S = ½ Molecular Species in Glassy Matrices or Magnetically-dilute Solids at Temperatures between 10 and 300 K, Y. Zhou, B. E. Bowler, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 139, 165-174 (1999).

    Electron Spin Lattice Relaxation Processes for Molecular S=1/2 Systems in Glassy Matrices at Temperatures between 10 and 130 K, Y. Zhou, R. Mitri, G. R. Eaton, and S. S. Eaton, Current Topics in Biophysics 23, 65-70 (1999).

    Instrumentation

    An X-band Saturation Recovery EPR Spectrometer Based on an Arbitrary Waveform Generator, J. McPeak, R. W. Quine, S. S. Eaton, and G. R. Eaton, Rev. Sci. Instrum. 90, 024102 (2019).

    Pulsed Saturation Recovery 250 MHz Electron Paramagnetic Resonance Spectrometer, R. W. Quine, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson. B, (Magn. Reson. Engin.) 26B, 23-27 (2005).

    A saturation recovery electron paramagnetic resonance spectrometer, R. W. Quine, S. S. Eaton, and G. R. Eaton, Rev. Sci. Instrum. 63, 4251-4262 (1992).

    Pulsed EPR Spectrometer, R. W. Quine, G. R. Eaton, and S. S. Eaton, Rev. Sci. Instrum. 58, 1709-1724 (1987).

    Distance Measurements

    Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins, Z. Yang, R. A. Stein, T. Ngendahimana, M. Pink, S. Rajca, G. Jeschke, S. S. Eaton, G. R. Eaton, H. S. Mchaourab, and A. Rajca, J. Phys. Chem. B., 124, 3291 – 3299 (2020).

    Room-Temperature Distance Measurements of Immobilized Spin-Labeled Protein by DEER/PELDOR, V. Meyer, M. A. Swanson, L. J. Clouston, P. J. Boratyński, R. Stein, H. S. Mchaourab, A. Rajca, S. S. Eaton, and G. R. Eaton, Biophys. J. 108, 1213 – 1219 (2015).

    Electron Transfer Flavoprotein Domain II Orientation Monitored using Double Electron-Electron Resonance Between an Enzymatically Reduced, Native FAD Cofactor and Spin Labels, M. A. Swanson, V. Kathirvelu, T. Majtan, F. E. Frerman, G. R. Eaton, and S. S. Eaton, Protein Science 20, 610-620 (2011).

    A Spirocyclohexyl Nitroxide Amino Acid Spin Label for Pulsed EPR Distance Measurements, A. Rajca, V. Kathirvelu, S. K Roy, M. Pink, S. Rajca, S. Sarkar, S. S. Eaton, and G. R. Eaton, Chem. Eur. J. 16, 5778-5782 (2010).

    Interaction of Radical Pairs Through-Bond and Through-Space: Scope and Limitations of the Point-Dipole Approximation in Electron Paramagnetic Resonance Spectroscopy, C. Riplinger, J. P. Y. Kao, G. M. Rosen, V. Kathirvelu, G. R. Eaton, S. S. Eaton, A. Kutateladze, F. Neese, J. Amer. Chem. Soc. 131, 10092-10106 (2009).

    Relaxation Rates for Spirocyclohexyl Nitroxyl Radicals are Suitable for Interspin Distance Measurements at Temperatures up to about 125 K, V. Kathirvelu, C. Smith, C. Parks, Md. A. Mannan, Y. Miura, K. Takeshita, S. S. Eaton, and G. R. Eaton, Chem. Commun., 454-456 (2009).

    Electron-Electron Distances in Spin-Labeled Low-Spin Metmyoglobin Variants by Relaxation Enhancement, D. Ulyanov, B. E. Bowler, G. R. Eaton, and S. S. Eaton, Biophysical Journal 95, 5306-5316 (2008).

    Interspin Distances in Spin-Labeled Metmyoglobin Variants Determined by Saturation Recovery EPR, Y. Zhou, B. E. Bowler, K. Lynch, S. S. Eaton, and G. R. Eaton, Biophys. J. 79, 1039-1052 (2000).

    Interspin Distances Determined by Time Domain EPR of Spin-Labeled High-Spin Methemoglobin, M. Seiter, V. Budker, J.-L. Du, G. R. Eaton, and S. S. Eaton, Inorganica Chimica Acta 273, 354-366 (1998).

    Determination of High-Spin Iron(III)-Nitroxyl Distances in Spin-Labeled Porphyrins by Time-Domain EPR, M. H. Rakowsky, A. Zecevic, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 131, 97-110 (1998).

    Enhancement of Electron Spin Relaxation Rates of Metalloporphyrins due to Interaction with a Faster Relaxing Metal Bound to an Appended Bipyridyl, J. M. Burchfield, J.-L. Du, K. M. More, S. S. Eaton, and G. R. Eaton, Inorg. Chim. Acta 263, 23-33 (1997).

    Electron-Electron Spin-Spin Interaction in Spin-Labeled Low-Spin Methemoglobin, V. Budker, J.-L. Du, M. Seiter, G. R. Eaton, and S. S. Eaton, Biophys. J. 68, 2531-2542 (1995).

    Time-Domain Electron Paramagnetic Resonance as a Probe of Electron-Electron Spin-Spin Interaction in Spin-Labeled Iron Porphyrins, M. H. Rakowsky, K. M. More, A. V. Kulikov, G. R. Eaton, and S. S. Eaton, J. Amer. Chem. Soc. 117, 2049-2057 (1995).

    Spin Lattice Relaxation for Organic Radicals

    W. Moore, R. Yao, Y. Liu, S.S. Eaton, G.R. Eaton, Electron Spin Relaxation in Trityl-Nitroxide Diradicals at X-band, J. Magn. Reson. 332, 107078 (2021).

    Impact of Chlorine Substitution on Electron Spin Relaxation of a Trityl Radical, W. Moore, J. L. Huffman, B. Driesschaert, S. S. Eaton, and G. R Eaton, Appl. Magn. Reson. 52, (2021).

    Perchlorinated Triarylmethyl Radical 99% Enriched 13C at the Central Carbon as EPR Spin Probe Highly Sensitive to Molecular Tumbling, J. L. Huffman, M. Poncelet, W. Moore, S. Eaton, G. Eaton, and B. Driesschaert, J. Phys. Chem. B125, 7380 - 7387 (2021).

    13C Isotope Enrichment of the Central Trityl Carbon Decreases Fluid Solution Electron Spin Relaxation Times, W. Moore, J. McPeak, M. Poncelet, B. Driesschaert, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 318, 106797 (2020).

    Measurement of T1e, T1N, T1HE, T2e, and T2HE by Pulse EPR at X-band for nitroxides at concentrations relevant to solution DNP, J. R. Biller, J. E. McPeak, S. S. Eaton, and G. R. Eaton,  Appl. Magn. Reson. 49, 1235 – 1251 (2018).

    Electron Spin Relaxation of a Boron-Containing Heterocyclic Radical, S. S. Eaton, K. Huber, H. Elajaili, J. McPeak, G. R. Eaton, L. E. Longobardi, and D. W. Stephan, J. Magn. Reson. 276, 7-13 (2017).

    Effect of Lanthanide and Cobalt Ions on Electron Spin Relaxation of Tempone in Glassy Water:Glycerol at 20 to 200 K, P. Aggarwal, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 47, 1123 – 1134 (2016). 

    X-band electron spin relaxation times for four aromatic radicals in fluid solution and comparison with other organic radicals, V. Meyer, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 45, 993 – 1007 (2014).

    Frequency Dependence of Electron Spin-lattice Relaxation for Semiquinones in Alcohol Solutions, H. B. Elajaili, J. R. Biller, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 247, 81 – 87 (2014).

    Electron Spin Lattice Relaxation Mechanisms of Rapidly-Tumbling Nitroxide Radicals, J. R. Biller, H. Elajaili, V. Meyer, G. M. Rosen, S. S. Eaton, and G. R. Eaton, J. Magn. Reson., 236, 47 – 56 (2013).

    Temperature Dependence of Electron Spin Relaxation of 2,2-diphenyl-1-picrylhydrazyl in Polystyrene, V. M. Meyer, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 44, 509-517 (2013).

    Organic Radical Contrast Agents for Magnetic Resonance Imaging, A. Rajca, Y. Wang, M. Boska, J. T. Paletta, A. Olankitwanit, M. A. Swanson, D. G. Mitchell, S. S. Eaton, G. R. Eaton, S. Rajca, J. Amer. Chem. Soc. 134, 15724 – 15727 (2012).

    Temperature Dependence of Electron Spin Relaxation of 2,2-diphenyl-1-picrylhydrazyl in Polystyrene, V. M. Meyer, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson., accepted for publication.

    Frequency Dependence of Electron Spin Relaxation Times in Aqueous Solution for a Nitronyl Nitroxide Radical and Per-deuterated-Tempone between 250 MHz and 34 GHz, J. R. Biller, V. M. Meyer, H. Elajaili, G. M. Rosen, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 225, 52 – 57 (2012).

    Relaxation Times and Line Widths of Isotopically-Substituted Nitroxides in Aqueous Solution at X-band, J. R. Biller, V. Meyer, H. Elajaili, G. M. Rosen, J. P.Y. Kao, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 212, 370-377 (2011).

    Electron Spin Relaxation and Heterogeneity of the 1:1 α,γ-Bisdiphenylene-β-phenylallyl (BDPA) : Benzene Complex, D. G. Mitchell, R. W. Quine, M. Tseitlin, R. T. Weber, V. Meyer, A. Avery, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. B 115, 7986-7990 (2011).

    Impact of Chlorine Substitution on Spin Lattice Relaxation of Triarylmethyl and 1,4-Benzosemiquinone Radicals in Glass-forming Solvents between 25 and 295 K, V. Kathirvelu, G. R. Eaton, and S. S. Eaton, Appl. Magn. Reson. 37, 649-656 (2010).

    Electron Spin Relaxation Rates for Semiquinones between 25 and 295 K in Glass-Forming Solvents, V. Kathirvelu, H. Sato, S. S. Eaton and G. R. Eaton, J. Magn. Reson. 198, 111-120 (2009).

    Impact of electron-electron spin interaction on electron spin relaxation of nitroxide diradicals and tetraradical in glassy solvents between 10 and 300 K, H. Sato, V. Kathirvelu, G. Spagnol, S. Rajca, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. B 112, 2818-2828 (2008).

    Electron spin-lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids, H. Sato, S. E. Bottle, J. P. Blinco, A. S. Micallef, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 191, 66-77 (2008).

    Impact of molecular size on electron spin relaxation rates of nitroxyl radicals in glassy solvents between 100 and 300 K, H. Sato, V. Kathirvelu, A. Fielding, J. P. Blinco, A. S. Micallef, S. E. Bottle, S. S. Eaton, and G. R. Eaton, Mol. Phys. 105, 2137-2151 (2007).

    Electron Spin Relaxation of Radicals in Irradiated Tooth Enamel and Synthetic Hydroxyapatite, H. Sato, B. A. Filas, S. S. Eaton, and G. R. Eaton, Radiation Measurements, 42, 997-1004 (2007).

    Electron Spin Relaxation in x-Lithium Phthalocyanine, H. Sato, L. A. Dalton, D. Ha, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. B 111, 7972-7977 (2007).

    Electron Spin-Lattice Relaxation in Radicals Containing Two Methyl Groups, Generated by gamma-Irradiation of Polycrystalline Solids, J. R. Harbridge, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 159, 195-206 (2002).

    Multifrequency EPR of Four Triarylmethyl Radicals, A. J. Fielding, P. J. Carl, G. R. Eaton, and S. S. Eaton, Appl. Magn. Reson. 28, 231-238 (2005).

    Frequency (250 MHz to 9.2 GHz) and Viscosity Dependence of Electron Spin Relaxation of Triarylmethyl Radicals at Room Temperature, R. Owenius, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 172, 168-175 (2005).

    Frequency Dependence of Electron Spin Relaxation of Nitroxyl Radicals in Fluid Solution, R. Owenius, G. E. Terry, M. J. Williams, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. B. 108, 9475-9481 (2004).

    Electron Spin Relaxation of Radicals in gamma-irradiated Malonic Acid and Methyl Malonic Acid, J. R. Harbridge, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 24, 261-276 (2003).

    Electron Spin-Lattice Relaxation Processes in Irradiated Crystalline Organic Compounds, J. R. Harbridge, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. A 107, 598-610 (2003).

    Electron Spin Relaxation of Triarylmethyl Radicals in Fluid Solution, L. Yong, J. Harbridge, R. W. Quine, G. A. Rinard, S. S. Eaton, G. R. Eaton, C. Mailer, E. Barth, and H. J. Halpern, J. Magn. Reson. 152, 156-161 (2001).

    Frequency Dependence of Electron Spin Relaxation for Three S=1/2 Species Doped into Diamagnetic Solid Hosts, S. S. Eaton, J. Harbridge, G. A. Rinard, G. R. Eaton and R. T. Weber, Appl. Magn. Reson. 20, 151-157 (2001).

    Magnetic Field and Frequency Dependence of Electron Spin Relaxation Times of the E' Center in Irradiated Vitreous Silica, B. T. Ghim, S. S. Eaton, G. R. Eaton, R. W. Quine, G. A. Rinard, and S. Pfenninger, J. Magn. Reson. A115, 230-225 (1995).

    Temperature, Orientation, and Solvent Dependence of Electron Spin Lattice Relaxation Rates for Nitroxyl Radicals in Glassy Solvents and Doped Solids, J.-L. Du, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. A115, 213-221 (1995).

    Electron Spin Relaxation Times of Irradiated Alanine, K. Nakagawa, S. S. Eaton, and G. R. Eaton, Appl. Radiat. Isotop. 44, 73-76 (1993).

    Spin Lattice Relaxation for Transition Metal Complexes

    Electron Paramagnetic Resonance Characterization and Electron Spin Relaxation of Manganate Ion in Glassy Alkaline LiCl Solution and Doped into Cs2SO4, S. N. Mahapatro, T. A. Hovey, T. Ngendahimana, S. S. Eaton, and G. R. Eaton, J. Inorg. Biochem, J. Inorg. Biochem, 229, 111732 (2022).

    Electron Paramagnetic Resonance of Lanthanides, J. E. McPeak, S. S. Eaton, G. R. Eaton, in Rare earth biochemistry, biology, and bio-applications, Methods in Enzymology, Vol. 651. A. Cotruvo, ed., Elsevier, ch 3, pp 63 – 101, 2021.

    Electron Spin Relaxation of Tb3+ and Tm3+ Ions, J. McPeak, D. Alexander, C. Joseph, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 51, 961 – 976 (2020).

    Comparison of spin lattice relaxation rates for transition metal complexes obtained by multiple methods of analyzing inversion recovery data, T. Ngendahimana, R. Ayikpoe, J. A. Latham, G. R. Eaton, and S. S. Eaton, J. Inorg. Biochem. (2019)

    Electron Spin Lattice Relaxation of V(IV) Complexes in Glassy Solutions between 15 and 70 K, A. J. Fielding, D. B. Back, M. Engler, B. Baruah, D. C. Crans, G. R. Eaton, and S. S. Eaton, ACS Symposium Series 974, 364-375 (2007).

    Electron Spin Relaxation of Copper(II) Complexes in Glassy Solution between 10 and 120 K, A. J. Fielding, S. Fox, G. L. Millhauser, M. Chattopadhyay, P. M. H. Kroneck. G. Fritz, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 179, 92-104 (2006).

    Electron Spin-Lattice Relaxation Rates for High-Spin Fe(III) Complexes in Glassy Solvents or Magnetically-dilute Solids at Temperatures between 6 and 298 K, Y. Zhou, B. E. Bowler, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 144, 115-122 (2000).

    Electron Spin Relaxation in Chromium Nitrosyl Complexes, L. M. Carruthers, C. L. Closken, K. Link, S. N. Mahapatro, M. Bikram, J.-L. Du, S. S. Eaton, and G. R. Eaton, Inorg. Chem. 38, 3529-3534 (1999).

    Electron Spin Relaxation Rates for High-spin Fe(III) in Iron Transferrin Carbonate and Iron Transferrin Oxalate, B. J. Gaffney, G. R. Eaton, and S. S. Eaton, J. Phys. Chem. B 102, 5536-5541 (1998).

    Electron Spin Relaxation in Vanadyl, Copper(II), and Silver(II) Porphyrins in Glassy Solvents and Doped Solids, J.-L. Du, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. A119, 240-246 (1996).

    Temperature and Orientation Dependence of Electron Spin Relaxation in Molybdenum(V) Porphyrins, R. Husted, J.-L. Du, G. R. Eaton, and S. S. Eaton, Magn. Reson. Chem. 33, 66S-70S (1995).

    Temperature and Orientation Dependence of Electron Spin Relaxation Rates for Bis(diethyldithiocarbamato)Copper(II), J.-L. Du, G. R. Eaton, and S. S. Eaton., J. Magn. Reson. A117, 67-72 (1995).

    Electron Spin Lattice Relaxation in Natural Abundance and Isotopically Enriched Oxo-chromium(V)bis(2-hydroxy-ethylbutyrate), J.-L. Du, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. A115, 236-240 (1995).

    Electron Spin Relaxation Rates for Nitridochromium(V) Tetratolylporphyrin and Nitridochromium(V) Octaethylporphyrin in Frozen Solution, R. Konda, J.-L. Du, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 7, 185-193 (1994).

    Spin Echo Dephasing

    Bis-Spiro-Oxetane and Bis-Spiro-Tetrahydrofuran Pyrroline Nitroxide Radicals: Synthesis and Electron Spin Relaxation Studies, S. Huang, M. Pink, T. Ngendahimana, S. Rajca, G. R. Eaton and S. S. Eaton, J. Org. Chem. 86, 13636 – 13643 (2021).

    Counterion Influence on Dynamic Spin Properties in a V(IV) Complex, C.-Y. Lin, T. Ngendahimana, G. R. Eaton, S. S. Eaton, and J. M. Zadrozny, Chemical Science 10, 548 – 555 (2019).

    Azaadamantyl Nitroxide Spin Label: Complexation with b-Cyclodextrin and Electron Spin Relaxation,  S. S. Eaton, A. Rajca, Z. Yang, and G. R. Eaton, Free Radical Research 52, 319 – 326 (2018).

    Synthesis and Electron Spin Relaxation of Tetra-Carboxylate Pyrroline Nitroxides, S. Huang, J. T. Paletta, H. Elajaili, K. Huber, M. Pink, S. Rajca, G. R. Eaton, S. S. Eaton, and A. Rajca, J. Org. Chem. 82, 1538 – 1544 (2017).

    Organic Radical Contrast Agents for Magnetic Resonance Imaging, A. Rajca, Y. Wang, M. Boska, J. T. Paletta, A. Olankitwanit, M. A. Swanson, D. G. Mitchell, S. S. Eaton, G. R. Eaton, S. Rajca, J. Amer. Chem. Soc 134, 15724 – 15727 (2012).

    Electron Spin T2 of a Nitroxyl Radical at 250 MHz Measured by Rapid Scan EPR, M. Tseitlin, A. Dhami, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 30, 651-656 (2006).

    Comparison of Electron Spin Relaxation Times Measured by Carr-Purcell-Meiboom-Gill and Two-Pulse Spin Echo Sequences, J. R. Harbridge, S. S. Eaton and G. R. Eaton, J. Magn. Reson. 164, 44-53 (2003).

    Phase Memory Relaxation Times of Spin Labels in Human Carbonic Anhydrase II: Pulsed EPR to Determine Spin Label Location, M. Huber, M. Lindgren, P. Hammarström, L.-G. Mårtensson, U. Carlsson, G. R. Eaton, and S. S. Eaton, Biophys. Chem. 94, 245-256 (2001).

    Solvent and Temperature Dependence of Spin Echo Dephasing for Chromium(V) and Vanadyl Complexes in Glassy Solution, G. R. Eaton and S. S. Eaton, J. Magn. Reson. 136, 63-68 (1999).

    Dephasing of Electron Spin Echoes for Nitroxyl Radicals in Glassy Solvents by Non-methyl and Methyl Protons, A. Zecevic, G. R. Eaton, S. S. Eaton, and M. Lindgren, Mol. Phys. 95, 1255-1263 (1998).

    Electron Spin Echo Decay as a Probe of Aminoxyl Environment in Spin-Labeled Mutants of Human Carbonic Anhydrase II, M. Lindgren, G. R. Eaton, S. S. Eaton, B.-H. Jonsson, P. Hammarström, M. Svensson, and U. Carlsson, Perkin Trans. 2, 2547-2554 (1997).

    Effect of Molecular Motion on Electron Spin Phase Memory Times for Copper(II) in Doped Solids, J.-L. Du, G. R. Eaton, and S. S. Eaton, Appl. Magn. Reson. 6, 373-378 (1994).

    Orientation dependence of electron spin phase memory relaxation times in copper(II) and vanadyl complexes in frozen solution, J.-L. Du, K. M. More, S. S. Eaton, and G. R. Eaton, Israel J. Chem. 32, 351-355 (1992).

    Electron Spin Relaxation Times of Chromium(V), K. Nakagawa, M. B. Candelaria, W. W. C. Chik, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 98, 81-91 (1992).

  • Low Frequency Publications

    Frequency Dependence of Electron Spin Relaxation Times in Aqueous Solution for a Nitronyl Nitroxide Radical and Per-deuterated-Tempone between 250 MHz and 34 GHz, J. R. Biller, V. M. Meyer, H. Elajaili, G. M. Rosen, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 225, 52 – 57 (2012).

    Multi-frequency EPR Sensitivity, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, in Multifrequency Electron Paramagnetic Resonance: Theory and Applications, S. K. Misra, Ed., Ch. 5.2, Wiley-VCH, 2011.

    Digital EPR with an arbitrary waveform generator and direct detection at the carrier frequency, M. Tseitlin, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 213, 119-125 (2011).

    Use of polyphase continuous excitation based on the Frank sequence for EPR, M. Tseitlin, R. W. Quine, S. S. Eaton, G. R. Eaton, J. Magn. Reson. 211, 221-227 (2011).

    Rapid Frequency Scan EPR, M. Tseitlin, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 211, 156-161 (2011).

    Use of the Frank Sequence in Pulsed EPR, M. Tseitlin, R. W. Quine, S. S. Eaton, G. R. Eaton, H. J. Halpern, and J. H. Ardenkjaer-Larsen, J. Magn. Reson. 209, 306-309 (2011).

    Quantitative Rapid Scan EPR Spectroscopy at 258 MHz, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 205, 23-27 (2010).

    A Very Fast Switched Attenuator Circuit for Microwave and R.F. Applications, R. W. Quine, M. Tseytlin, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson. B, Magn. Reson. Engineer, 37B, 39-44 (2010).

    A Wire Crossed-Loop-Resonator for Rapid Scan EPR, G. A. Rinard, R. W. Quine, J. R. Biller, and G. R. Eaton, Concepts Magn. Reson. B, (Magn. Reson. Engin.) 37B, 86-91 (2010).

    A Linear Magnetic Field Scan Driver, R. W. Quine, T. Czechowski, and G. R. Eaton, Conc. Magn. Reson. B (Magn. Reson. Engin.) 35B, 44-58 (2009).

    Electron Spin T2 of a Nitroxyl Radical at 250 MHz Measured by Rapid Scan EPR, M. Tseitlin, A. Dhami, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 30, 651-656 (2006).

    Fast-Response VHF Pulsed 2 KW Power Amplifiers, R. W. Quine, G. R. Eaton, and S. Dillon, Conc. Magn. Reson. B (Magn. Reson. Engin.) 29B, 185-190 (2006).

    Fast-Response VHF Pulsed Power Amplifiers, R. W. Quine, G. R. Eaton, S. Dillon, and D. Myer, Conc. Magn. Reson. B (Magn. Reson. Engin.) 27B, 1-7 (2005).

    Pulsed Saturation Recovery 250 MHz Electron Paramagnetic Resonance Spectrometer, R. W. Quine, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson. B (Magn. Reson. Engin.) 26B, 23-27 (2005).

    Rapid-Scan EPR with Triangular Scans and Fourier Deconvolution to Recover the Slow-Scan Spectrum, J. P. Joshi, J. R. Ballard, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 175, 44-51 (2005).

    Multifrequency EPR of Four Triarylmethyl Radicals, A. J. Fielding, P. J. Carl, G. R. Eaton, and S. S. Eaton, Appl. Magn. Reson. 28, 231-238 (2005).

    Frequency (250 MHz to 9.2 GHz) and Viscosity Dependence of Electron Spin Relaxation of Triarylmethyl Radicals at Room Temperature, R. Owenius, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 172, 168-175 (2005).

    Direct-detected rapid-scan EPR at 250 MHz, J. W. Stoner, D. Szymanski, S. S. Eaton, R. W. Quine, G. A. Rinard, and G. R. Eaton, J. Magn. Reson. 170, 127-135 (2004).

    Frequency Dependence of Electron Spin Relaxation of Nitroxyl Radicals in Fluid Solution, R. Owenius, G. E. Terry, M. J. Williams, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. B, 108, 9475-9481 (2004).

    EPR Spectrometers at Frequencies Below X-band, G. R. Eaton and S. S. Eaton, Biological Magnetic Resonance, C. Bender and L. J. Berliner, eds. 21, 59-114 (2004).

    Frequency Dependence of EPR Sensitivity, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, Biological Magnetic Resonance, C. Bender and L. J. Berliner, eds. 21, 115-154 (2004).

    Frequency Dependence of EPR Signal Intensity, 250 MHz to 9.1 GHz, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 156, 113-121 (2002).

    A Pulsed and Continuous Wave 250 MHz Electron Paramagnetic Resonance Spectrometer, R. W. Quine, G. A. Rinard, S. S. Eaton, G. R. Eaton, Magn. Reson. Engineer. 15, 59-91 (2002).

    Magnet and Gradient Coil System for Low-Field EPR Imaging, G. A. Rinard, R. W. Quine, S. S. Eaton, G. R. Eaton, E. D. Barth, C. A. Pelizzari, and H. J. Halpern, Magn. Reson. Engineer. 15, 51-58 (2002).

    Adapting a Hall Probe Controller for Current Control of an Air-Core Magnet, G. A. Rinard, R. W. Quine, G. R. Eaton, and S. S. Eaton, Magn. Reson. Engineer. 15, 47-50 (2002).

    250 MHz Crossed Loop Resonator for Pulsed Electron Paramagnetic Resonance, G. A. Rinard, R. W. Quine, G. R. Eaton, and S. S. Eaton, Magn. Reson. Engineer. 15, 37-46 (2002).

    Frequency Dependence of EPR Signal Intensity, 248 MHz to 1.4 GHz, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 154, 80-84 (2002).

    Multifrequency EPR of Ultramarine Blue, G. R. Eaton, S. S. Eaton, J. W. Stoner, R. W. Quine, G. A. Rinard, A. I. Smirnov, R. T. Weber, J. Krzystek, A. K. Hassan, L.-C. Brunel, and A. Demortier, Appl. Magn. Reson. 21, 563-570 (2001).

    Electron Spin Relaxation of Triarylmethyl Radicals in Fluid Solution, L. Yong, J. Harbridge, R. W. Quine, G. A. Rinard, S. S. Eaton, G. R. Eaton, C. Mailer, E. Barth, and H. J. Halpern, J. Magn. Reson. 152, 156-161 (2001).

    Frequency Dependence of Electron Spin Relaxation for Three S=1/2 Species Doped into Diamagnetic Solid Hosts, S. S. Eaton, J. Harbridge, G. A. Rinard, G. R. Eaton and R. T. Weber, Appl. Magn. Reson. 20, 151-157 (2001).

    An L-band Crossed-Loop (Bimodal) Resonator, G. A. Rinard, R. W. Quine, and G. R. Eaton, J. Magn. Reson. 144, 85-88 (2000).

    Frequency Dependence of EPR Signal-to-Noise, G. A. Rinard, R. W. Quine, J. R. Harbridge, R. Song, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 140, 218-227 (1999).

  • Other Spectrometer Publications

    Single Mutations in Tau Modulate the Populations of Fibril Conformers through Seed Selection, V. Meyer, P. D. Dinkel, Y. Luo, X. Yu, G. Wei, J. Zheng, G. R. Eaton, G. B. Ma, R. Nussinov, S. S. Eaton, and M. Margittai, Angew. Chem. Int. Ed., 53, 1590-1593

    Remote Delivery of Hydroxyl Radicals via Secondary Chemistry of a Nonthermal Plasma Effluent, S. R. Plimpton, M. Gołkowski, D. G. Mitchell, C. Austin, S. S. Eaton, G. R. Eaton,  C. Gołkowski, and M. Voskuil, Biotech. & Bioeng. 110, 1936-1944 (2013).

    Conformational Basis for Asymmetric Seeding Barrier in Filaments of Three- and Four-repeat Tau, A. Siddiqua, Y. Luo, V. Meyer, M. A. Swanson, X. Yu, G. Wei, J. Zheng, G. R. Eaton, B. Ma, R. Nussinov, S. S. Eaton, and M. Margittai, J. Amer. Chem. Soc. 134, 10271 – 10278 (2012).

    The World as Viewed by and with Unpaired Electrons, S. S. Eaton and G. R. Eaton, J. Magn. Reson. 223, 151 – 163 (2012). (invited perspectives article)

    Electron Paramagnetic Resonance, G. R. Eaton and S. S. Eaton, in Characterization of Materials, E. Kaufmann, ed., John Wiley & Sons, published on-line May 2012, 10.1002/0471266965.com067.pub2, Vol 2, 1232 – 1244 (2012).

    Electron Paramagnetic Resonance Imaging, G. R. Eaton and S. S. Eaton in Encyclopedia of Analytical Chemistry, R. A. Meyers, ed., John Wiley: Chichester. DOI: 10.1002/9780470027318.a9175. Published 15th March 2011

    Multi-frequency EPR Sensitivity, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, in Multifrequency Electron Paramagnetic Resonance: Theory and Applications, S. K. Misra, Ed., Ch. 5.2, Wiley-VCH, 2011.