title: An improved external loop resonator for in vivo L-band EPR spectroscopy.
abstract: An improved external loop resonator (ELR) used for L-band electron paramagnetic resonance (EPR) spectroscopy is reported. This improvement is achieved by shortening the parallel coaxial line. The resonant structure is formed by two single turn coils (10mm in diameter) that are connected to a parallel coaxial line. A resonance frequency of 1197 MHz and a quality factor of 466 were obtained in the absence of biological tissue and were approximately 1130 MHz and approximately 50 with a living animal, respectively. The sensitivity of the new ELR was compared to the previously developed ELR using three types of EPR samples: (1) paramagnetic material with no biological tissue, (2) paramagnetic material in a leg and in the peritoneal cavity of a dead rat, and (3) paramagnetic material in the back of an anesthetized rat. The sensitivity was 1.2-1.6 times greater in the rat and 4.2 times without tissue.
authors.affiliation: EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH 03755, USA.
authors.forename: Ildar
authors.initials: I
authors.lastname: Salikhov
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirata
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Walczak
authors.forename: Harold M
authors.initials: HM
authors.lastname: Swartz
mesh_terms: D000818:Animals; D001415:Back; D001713:Biphenyl Compounds / Q000737:chemistry* / Q000493:pharmacokinetics; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D006614:Hindlimb / Q000737:chemistry / Q000378:metabolism; D006834:Hydrazines / Q000737:chemistry* / Q000493:pharmacokinetics; D066298:In Vitro Techniques; D008280:Magnetics / Q000295:instrumentation*; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D010537:Peritoneum / Q000737:chemistry / Q000378:metabolism; D010851:Picrates; D011786:Quality Control; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001713:Biphenyl Compounds; D006834:Hydrazines; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl