• The Korean Journal of Mycology
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• v.30 no.2
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• pp.136-141
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• 2002

A hot water extract was prepared from the artificially grown Gastrodia elata to investigate its chemical composition and various in vitro biological activities as an effort to develop G. elata as health/functional food materials. The contents of crude protein, ash, fat, fiber, moisture and total sugar were 5.4, 2.6, 3.6, 3.3, 8.1 and 77% (w/w), respectively. The extract of G. elata had greater amount of potassium (1,150 mg/100 g) than phosphorus (300 mg/100 g). Dose-dependence against human carcinoma (Hep3B, MCF-7, A549 and AGS) were observed from 0.2 mg/ml to 1.0 mg/ml. Especially, the treatment of 1.0 mg/ml extracts showed the highest cytotoxicity with 83% against gastric carcinoma (AGS). The extracts showed weak antimicrobial activities against Bacillus subtilis and Pseudomonas aeruginosa, but practically no antimicrobial activity against the other microorganisms tested. The effect of ${\alpha}$-glucosidase inhibition was 64% at the concentration of 1.0 mg/ml. The inhibitory effect of angiotensin converting enzyme (ACE) of the extract in the range of $0.2{\sim}1.0mg/ml$ showed $63{\sim}89%$, and the highest ACE inhibition was 89% at the concentration of 1.0 mg/ml of extracts. The highest activity of glutathion S-transferase (GST) was 221 % at the concentration of 1.0 mg/ml of the G. elata extracts. These results suggest that G. elata may be used as health/functional food materials.

• Progress in Medical Physics
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• v.9 no.1
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• pp.11-21
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• 1998

Circular metal electrodes were vacuum-deposited with chromium on the both sides of Teflon-FEP and PET film characteristic of electret and the physical properties of the two polymers were observed during an irradiation by gamma-ray from $\^$60/Co. With the onset of irradiation of output 25.0 cGy/min the induced current increased rapidly for 2 sec, reached a maximum, and subsequently decreased. A steady-state induced current was reached about in 60 second. The dielectric constant and conductivity of Teflon-FEP were changed from 2.15 to 18.0 and from l${\times}$l0$\^$-17/ to 1.57${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/, respectively. For PET the dielectric constant was changed from 3 to 18.3 and the conductivity from 10$\^$-17/ to 1.65${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/. The increase of the radiation-induced steady state current I$\^$c/, permittivity $\varepsilon$ and conductivity $\sigma$ with output(4.0 cGy/min, 8.5 cGy/min, 15.6 cGy/min, 19.3 cGy/min) was observed. A series of independent measurements were also performed to evaluate reproducibility and revealed less than 1% deviation in a day and 3% deviation in a long term. Charge and current showed the dependence on the interval between measurements, the smaller the interval was, the bigger the difference between initial reading and next reading was. At least in 20 minutes of next reading reached an initial value. It may indicate that the polymers were exhibiting an electret state for a while. These results can be explained by the internal polarization associated with the production of electron-hole pairs by secondary electrons, the change of conductivity and the equilibrium due to recombination etc. Heating to the sample made the reading value increase in a short time, it may be interpreted that the internal polarization was released due to heating and it contributed the number of charge carriers to increase when the samples was again irradiated. The linearity and reproducibility of the samples with the applied voltage and absorbed dose and a large amount of charge measured per unit volume compared with the other chambers give the feasibility of a radiation detector and make it possible to reduce the volume of a detector.

• Journal of Sensor Science and Technology
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• v.11 no.1
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• pp.9-17
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• 2002

The forming conditions of X-ray storage phosrhors $BaFBr_{1-x}I_x:Eu^{2+}$, $Na^+$ have been investigated, and measured the PSL emission spectra and its intensity, fading characteristics and does dependence of the prepared phosphors. These characteristics were compared with those of commercial image plate (ST-III) obtained from Fuji Photo Film Co. The optimal preparing conditions of $BaFBr_{1-x}I_x:Eu^{2+}$, $Na^+$ Phosphor were 0.5 mol% of $EuF_3$, 4.0 mol% of NaF and composition ratio x=0.3, and the sintering temperature were $950^{\circ}C$ in $H_2$ atmosphere. When the composition ratio x was equal to 0, the spectral range of the luminescence of $BaFBr_{1-x}I_x:Eu^{2+}$, $Na^+$ phosphor was $365{\sim}420\;nm$, and its maximum luminescence intensity appeared at 390 nm. When composition ratio x was not equal to 0, the wavelength ranges and peak of the spectra were shifted to the longer wavelength with the growth of composition ratio x. A good linearity was shown between the PSL intensity and X-ray irradiation dose. The phosphor sample with x=0.3 exhibited better fading characteristics than that of other $BaFBr_{1-x}I_x:Eu^{2+}$ phosphor samples, and the fading characteristics of the PSL intensity at room temperature were shown poorer with increasing $I^-$ ion concentration. The lattice constant of the phosphor becomes larger with increasing the $I^-$ ion concentration.