• The Plant Pathology Journal
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• v.21 no.3
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• pp.283-287
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• 2005

Since the discovery of generation of $O_2^-$ in plant, many evidence for the oxidative burst (OXB) has been accumulated in various combinations of plant and pathogen or elicitor systems. $O_2^-$ generating system responsible for the OXB was coupled with oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) in microsomal fraction isolated from sliced aged potato tuber slices which were treated by hyphal wall components elicitor from Phytophthora infestans (HWC). We developed new assay method for quantitative measurement of oxygen radical $O_2^-$ by using electron spin resonance (ESR) analysis during elicitor­induced OXB on the surface of plant tissues. The ESR analysis using an $O_2^-$ trapper, Tiron (1,2-dihydroxy-3,5­benzenedisulfonic acid), provided a convenient assay for detecting only $O_2^-$ during elicitor-induced OXB producing various active oxygen species (AOS) on plant tissue surface. Tiron was oxidized to Tiron semiquinon radical by $O_2^-$. Quantity of the radical signal was measured by specific spectra on ESR spectroscopy. The level of $O_2^-$ was high in from surface of potato tuber tissue treated with hyphal cell wall elicitor (HWC) from Phytophthora infestans. There was no secondary OXB induction by $H_2O_2$ treatment in plant.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.146-151
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• 2007

Gas phase and particulate phase radicals in mainstream cigarette smoke were determined Electron Spin Resonance(ESR) spectroscopy. The free radicals in particulate phase have been investigated by benzene extract of Cambridge Filter Pad containing the smoke condensate. Spin trapping method in conjunction with ESR was used to investigate free radicals in the gas phase of cigarette smoke. Several analytical experiments were conducted in order to determine the optimal conditions for maximum signal intensities and reproducibility of results. All the tests were optimized and normalized using the University of Kentucky 2R4F reference cigarette. The optimal conditions were 0.6 mL for analysis volume of ESR, $4{\sim}5\;mL$ for collection volume of spin-adducts, and PBN for quantification of free radicals in gas phase. The radical levels of Kentucky 2R4F cigarettes were found $2.18{\times}10^{14}\;spins/cig.$ and $2.10{\times}10^{15}\;spins/cig.$ in gas phase.

• Progress in Medical Physics
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• v.1 no.1
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• pp.31-42
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• 1990

The finding of long lived free radicals produced by ionizing radiation in organic crystals and the quantification of this effect by electron spin resonance(ESR) spactroscopy has proven excellent dosimetric applicability. The tissue equivalent alanine dosimeter also appear appropriate for radiation therapy level dosimetry. The dose measurement was performed in a Rando phantom using high energy photons as produced by high energy medical linear accelerator and cobalt-60 teletherapy unit. The absorbed dose range of the ESR/alanine dosimetry system could be extended down to 0.1 Gy. The response of the alanine dosimeters was determined for photons at different therapeutic dose levels from less than 0.1 Gy to 100 Gy and the depth dose measurements were carried out for photon energies of 1.25MeV, 6 and 10 MV with alanine dosimeters in Rando phantom. Comparisons between ESR/alanine in a Rando phantom and ion chamber in a water phantom were made performing depth dose measurements to examine the agreement of both methods under field conditions.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.119-123
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• 2012

The detection properties of gamma-irradiated (0~10 kGy) dried seaweed, dried shrimp, and seasoned dried filefish were investigated by photo-stimulated luminescence (PSL) and electron spin resonance (ESR). PSL could be used as a detection method on irradiated dried seaweed and dried shrimp as they showed photon counts greater than 5,000 counts/60 s (positive) in the irradiated samples with doses above l kGy. However, PSL could not be applied to detect irradiated seasoned dried filefish, because gamma-irradiated sample at 10 kGy even yielded photon counts less than 700 counts/60 s (negative). The ESR spectroscopy for only dried shrimp revealed specific signals derived from free radicals captured in the shell of shrimp. As a result, it is considered that PSL or ESR methods for detection of gamma-irradiated dried shrimp and only PSL can be used to detect gamma-irradiated seaweed. Furthermore, it is considered that hydrocarbon analysis of seasoned dried filefish containing fat by GC/MS and Thermo Luminance (TL) analysis of dried seaweed should be studied for detection of irradiation.

• Journal of the Korean Chemical Society
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• v.39 no.4
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• pp.237-243
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• 1995

The measurments of neutral semiquinone radicals, which were formed from the laser flash photolysis of anthraquinone (AQ) in the mixed solvents were carried out by the time resolved electron spin resonance (trESR) spectroscopy. The chemically induced dynamic electron polarization (CIDEP) spectra of the neutral semiquinone radical (AQH${\cdot}$) and semiquinone radical anion (AQ${\cdot}$-) were successively detected in the laser flash photolysis of AQ in the mixtures of 2-propanol (PrOH) and triethylamine (TEA). The neutral semiquinone radical was short-lived with the half-life of 0.8 ${\mu}sec$, whereas the semiquinone radical anion was relatively stable and then its cwESR could be observed. The rate constant of the spin-depolarization of semiquinone radical anion was $2.6{\times}10^5 sec^{-1}$ and the decay of the radical anion was the first order reaction with the rate constant of $3.0{\times}10^2\; sec^{-1}$. No CIDEP of semiquinone radical anion was observed in the mixture of PrOH and the lower concentration of TEA than 2 percent. The CIDEP spectrum of the neutral semiquinone radical was detected in the mixture of benzene and TEA with the half-life of 3.0 ${\mu}sec$. The neutral semiquinone radical could not be detected by cwESR. Neither CIDEP nor ESR absorption could be observed in PrOH, TEA or benzene only.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.173-174
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• 2002

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1454-1459
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• 2012

An improved detection of radiation-induced paramagnetic faults was developed to identify the irradiation status of basil and clove. The effectiveness of different sample pretreatments, including freeze-drying (FD), oven-drying (OD), alcoholic-extraction (AE), and water-washing and alcoholic-extraction (WAE), were examined. All non-irradiated samples showed a single central signal ($g_0$=2.006), whereas radicals representing two additional side peaks ($g_1$=2.023 and $g_2$=1.986) with a mutual distance of 6 mT were detected in the irradiated samples. AE and WAE produced the best results for irradiated clove in terms of intensities of radiation-specific ESR signals and their ratios to the central signal. However, FD provided the highest intensities of radiation-specific ESR signals for basil, whereas their ratios to the major signal were better in the cases of AE and WAE. Signal noise, particularly due to $Mn^{2+}$ signals, was observed, whereas it decreased in AE and WAE pretreatments. Based on our results, AE and WAE can improve the detection conditions for radiation-specific ESR signals in irradiated samples.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.131-135
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• 2009

The identification characteristics of irradiated commercial Ramen soup were investigated depending on radiation sources and doses by electron spin resonance (ESR) spectroscopy. Two commercial powder soups (RS-1, RS-2) were irradiated at 0 to 20 kGy under ambient conditions by both a Co-60 gamma irradiator and an electron beam (EB) accelerator, respectively. Crystalline sugar-induced multi-component signals with g-values of 2.010/2.011, 2.006, 2.002 and 1.999 were detected in the irradiated Ramen soup (RS-1, RS-2), whereas $Mn^{2+}$ signals were observed in non-irradiated samples, thereby distinguishing each other. Under the same analytical conditions, the intensity of ESR signals was higher in EB-irradiated samples than the gamma-irradiated ones. Determination coefficients ($R^2$) between irradiation doses and corresponding ESR responses were above 0.9665 in all the samples, and the magnetic field of specified g-value remained constant. The predominant ESR signals of $g_2$ (2.010-2.011) and $g_3$ (2.002) increased with corresponding doses of irradiation ($R^2$= 0.9750-0.9981).

• Journal of the Korean Chemical Society
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• v.38 no.1
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• pp.13-20
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• 1994

Substituted anthrasemiquinone radical anions, which were formed by laser flash photoreduction of the substituted anthraquinone (1,4-DHAQ, 1,5-DHAQ, 1,8-DHAQ, 1,8-DCAQ), were studied by the electron spin resonance spectroscopy in the mixed solvents of the 2-propanol and the triethylamine. Hyperfine splitting constants (hfsc) were determined by simulating the ESR spectra. Extended Huckel Molecular Orbital (EHMO) calculations were performed to obtain $\pi$ spin densities for these quinones. The hyperfine splitting constants could be assigned to specific protons on the basis of $\pi$ spin densities.

• Journal of the Korean Ceramic Society
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• v.45 no.3
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• pp.179-184
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• 2008

(40-x)BaO${\cdot}xFe_2O_3{\cdot}60P_2O_5$ glasses with $5{\leq}x{\leq}35mol%$ were investigated by ESR spectroscopy. Two resonances observed near g=2.0 and g=4.3. The line at g=4.3 disappeared with the increase of the $Fe_2O_3$ content. The resonance at $g{\approx}2.0$ displayed characteristic signal consisting of superposed extremely broad and narrow components. The broader one indicates the presence of the association of two or more $Fe^{3+}$ ions, antiferromagnetically and the narrow one is related to the microclusters involving iron ions. Temperature dependence of the ESR integrated intensity revealed short-range antiferromagnetic character for $x{\geq}15mol%$.