• Korean Journal of Microbiology
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• v.26 no.1
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• pp.44-51
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• 1988

The intracellular free radicals produced at different stages of cell cycle of Saccharomyces cerevisiae ATCC 24858 were investigated by means of electron spin resonance(ESR) spectroscopy. The synchronized cells by repeated starvation and refeeding revealed different ESR spectral pattern compared to that of asynchronized cells. Each spectrum centered at g=2.005, which indicates free radicals. The relative spin concentration was maximat at the end of DNA increase. The variation of the relative spin concentration at each distinct stage of the cell cycle was evaluated in relation to ascorbate concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. The highest activities of L-galactonolactone oxidase and ascorbate oxidase were detected just before and at the maximum of relative spin concentration, respectively. And ascorbate concentration fluctuated through each stage of cell cycle with the changes of relative spin concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. Thus it is suggested that intracellular free radicals should be related to cell cycle, interacted with ascorbate, and may play an important role in the cell cycle of Saccharomyces cerevisiae.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.1
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• pp.9-15
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• 2020

Nitrogen vacancy center (NV center) in diamond has recently been appeared as a promising candidate for hyperpolarization applications due to its optical pumping property by laser. Optically Detected Magnetic Resonance (ODMR) has been used as a conventional method to obtain the resonance spectrum of NV centers. ODMR, however, has a shortcoming of sensitivity and a limitation of subjects, such that the degree of hyperpolarization can hardly be estimated, and that the spins other than NV centers are invisible. In contrast, Electron Spin Resonance (ESR) spectroscopy is known to proportionally reflect the degree of spin polarization. In this work, we successfully observed the optically-induced hyperpolarization of NV spins in diamond through CW-ESR spectroscopy with an X-band system. All the NV peaks were identified by calculating the eigenvalues of NV spin Hamiltonian. The intensities of NV peaks were enhanced over 240 times after optical pumping. The enhanced peaks corresponding to the transition from |m_s=0> to |m_s=-1> revealed inverted phases, while other peaks remained in-phase. The optically-induced hyperpolarization on NV spins can be a useful polarization source, leading to ¹³C nuclear hyperpolarization in diamond.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.01a
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• pp.30-30
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• 2002

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.252-259
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• 2006

Extracts which were prepared by four different extractions - 80% methanol extracts (ME) at high ($70^{\circ}C$) and a room temperature ($20^{\circ}C$), respectively and aqueous extracts (AE) at both temperatures with the residue after the methanol extracts - of 10 green, 19 brown and 25 red seaweeds collected in Jeju Island coast were examined for their DPPH free radical scavenging activity using a ESR (electron spin resonance) spectroscopy. A variety of the extracts showed positive scavenging effect against DPPH free radical (except the green seaweeds). Among the extracts, the brown seaweed extracts exhibited the highest scavenging activity. Especially, Sargassum spp. of the brown seaweeds have remarkable scavenging activities - both methanolic and aqueous at the both temperatures ($20^{\circ}C$ and $70^{\circ}C$). On the other hand, ME showed better scavenging activity than AE in the red seaweed extracts. These results indicate that autogenous seaweeds in Jeju will be potential natural antioxidants for functional food compounds.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.01a
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• pp.15-15
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• 2002

• Journal of Environmental Science International
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• v.14 no.12
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• pp.1113-1117
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• 2005

Gamma-ray treatment was used to exterminate nematodes, which were harmful to agriculture When gamma-ray at the dose range of $5\~75$ kGy was irradaidated, nematodes were reduced by $40\~50\%$ When irradiated over 30 kGy, almost nematodes were non-mobile and fluorochromatic reactions showed that $60\;\~80\%$ of nematodes with non-mobility died after irradiation. The results of electron spin resonance spectroscopy suggested that radicals generated by radiolysis could damage to nematodes.

• Journal of the Korean Magnetics Society
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• v.20 no.3
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• pp.120-128
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• 2010

Electron spin resonance (ESR) is one of an experimental choice for studying magnetic materials that have one or more unpaired electrons. ESR spectroscopy finds its wide applications in branches of science encompassing physics, chemistry, biology, medicine and quantum computation. In this brief review we introduce a basic principle of ESR and describe how to extract information on g-factor, spin and orbital states from the ESR spectral parameters. Finally, several examples are discussed with an intention to have a practical feeling of what ESR can do in magnetism.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2000.11a
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• pp.162-162
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• 2000

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.1
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• pp.20-37
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• 2002

MnAPSO-34 and Mn-impregnated SAPO-34(Mn-SAPO-34) sample were prepared with various manganese contents and studied by electron spin resonance(ESR) and electron spin echo modulation(ESEM). Electron spin echo modulation analysis of 0.07mo1 ％ Mn(relative to p) in MnAPSO-34 with adsorbed D$_{2}$O shows two deuteriums at 0.26 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO$_{4}$ configuration with a D-O bond orientation for the waters as expect for a negatively charged site at low manganese content (0.1 mol％), the ESR spectra of MnAPSO-34 and MnH-SAPO-34 exhibit the same parameters(g 2.01 and A 89 G), but the spectra obtained from MnAPSO-34 samples are better resolved. The decomposition temperature of as-synthesized MnAPSO-34 were in the range of 200-600 $^{\circ}C$ of the morpholine which is 12 $^{\circ}C$ higher than that in as-synthesized MnH-SAPO-34. Infrared spectra showed that the position of a band at 3450 $cm^{-1}$ / shifted about 15 $cm^{-1}$ / toward higher energy in MnAPSO-34 versus MnH-SAPO-34. The modulation depth of the two-pulse ESE of MnAPSO-34 with adsorbed D$_{2}$O is deeper than that of MnH-SAPO-34 with adsorbed D$_{2}$O. Three-pulse ESEM of MnAPSO-34 and MnH-SAPO-34 with adsorbed deuterium oxide shows that the local environments of manganese in the hydrated samples are different, suggesting that Mn(II) is framework substituted in MnAPSO-34 since it obviously occupies an extraframework position in MnH-SAPO-34.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.08a
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• pp.80-80
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• 2002

MnPSO-34 and Mn-impregnated SAPO-34 (Mn-SAPO-34) sample were prepared with various manganese contents and studied by electron spin resonance (ESR) and electron spin-echo modulation (ESEM). Electron spin-echo modulation analysis of 0.07mol ％ Mn(relative to p) in MnAPSO-34 with adsorbed D$_2$O shows two deuteriums at 0.25 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO4 configuration with a D-O bond orientation for the waters as expect for a negatively charged site at low manganese content (0.07 mol％), the ESR spectra of MnAPSO-34 and MnH-SAPO-34 exhibit the same parameters (g 2.02 and A 87 G), but the spectra obtained from MnAPSO-34 samples are better resolved. TGA of as-synthesized MnAPSO-34 shows that the decomposition temperature in the range 200-$600^{\circ}C$ of the morpholine is 12$^{\circ}C$ higher than that in as-synthesized MnH-SAPO-34. Infrared spectra shows that the position of a band at about 15 cm-1 toward higher energy in MnAPSO-34 versus MnH-SAPO-34. The modulation depth of the two-pulse ESE of MnAPSO-34 with absorbed D$_2$O is deeper than that of MnH-SAPO-34 with absorbed D$_2$O. Three-pulse ESEM of MnAPSO-34 and MnH-SAPO-34 with absorbed deuterium oxide shows that the local environments of manganese in the hydrated samples are different, suggesting that Mn(II) is framework substituted in MnAPSO-34 since it obviously occupies an extra-framework position in MnH-SAPO-34