• The Korean Journal of Mycology
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• v.10 no.1
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• pp.33-39
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• 1982

Carpophores of ten Korean strains of Lentinus edodes (Berk.) Singer, an antitumor polysaccharide producing fungus, were extracted with 0.1N NaOH solution. The extracts were dialized for seven days in distilled water and lyophilized to produce crude polysaccharide powders. Thus obtained crude polysaccharide samples were assayed for sugar contents by colorimetric method with anthrone reagent. Among ten strains examined Lentinus edododes-DMC7 was found to be the richest strain in polysaccharide content of carpophores. By shake culture experiment for biomass production, L. edodes-DMC7 was found to be the second most productive strain among seven strains examined. Cultural characteristics of L. edodes-DMC7 were investigated by shake culture method. The best result was obtained when L. edodes-DMC7 was cultured in the medium containing glucose 8g, starch 80g, yeast extract 12g, $KH_2PO_4\;0.87g,\;MgSO_4{\cdot}7H_2O\;O.5g,\;CaCl_2\;0.3g,\;FeSO_4{\cdot}7H_2O\;10mg\;ZnSO_4{\cdot}7H_2O\;4mg,\;CuSO_4{\cdot}5H_2O\;lmg,\;MnCl_2{\cdot}4H_2O\;7mg\;per\;11\;at\;28^{\circ}C$, 180 rpm, for 12 days. Thus thirty-three grams of dry mycelia was obtained per one liter of medium.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.1-6
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• 2008

Purpose: Plastic optical monomer materials having ultra high refractive index have an income of the whole quantity from advanced nations to domestic companies which are related to plastic optical lens. It is necessary to develop novel plastic optical lens materials in order to overcome a FTA provision and revitalize a stagnating optical lens industry in the interior optical lens industries. The new plastic optical lens materials against the substitution effect of income should be gradually demanded. This work will be synthesized novel super high refractive monomer resin materials of urethane lens series and studied the properties of optical lens using it. Methods: ETS-4 (2-(2-mercaptoethylthio)-3-{2-[3-mercapto-2-(2-mercaptoethylthio)propyl thio]ethylthio}propane -1-thiol), which is optical lens monomer resin having super high refractive index, was synthesized and identified its structure and property by elemental analysis, EI-MS, TGA, FT-IR spectroscopy, $^1H$ and $^{13}C$ NMR spectroscopies. After mixing evenly from mixed monomer resin and diisocyanate series, it was casting in glass mold. After thermal curing, the obtained optical lenses were measured and compared with the refractive index and Abbe number for studies of their optical properties. Results: We have synthesized the novel ultra high refractive index monomer resin, ETS-4, and have identified its structure and property by elemental analysis, EI-MS, TGA, FT-IR spectroscopy, $^1H$ and $^{13}C$ NMR spectroscopies. The existence of three isomers for EST-4 was identified by $^{13}C$ NMR spectroscopy. The refractive index ($N_d$ at $25^{\circ}C$) of monomer resin in liquid state obtained from the Abbe refractometer was 1.647. The refractive indexes of raw plastic optical lenses prepared from the mixed ETS-4 monomer and diisocyanate series were in the range of 1.656~1.680. Conclusions: Novel super high refractive index plastic optical lens monomer was synthesized and analysed, the optical lenses prepared using it were colorless transparency and excellent properties. It is of utility for the industrialization.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.1
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• pp.35-42
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• 2018

Objectives: The objectives of this study are to research the usage characteristics of asbestos-containing building materials and to conduct exposure risk assessment by applying no. 2016-230 "Methods of Risk Assessment of Asbestos-Containing Buildings" from the Ministry of Environment. Methods: One hundred buildings located in the Seoul and Gyeonggi-Incheon area were chosen, with 29 in Seoul, 20 in Incheon, and 51 in Gyeonggi-do Province. The year of construction was divided between three buildings in the 1970s, 11 buildings in the 1980s, 42 buildings in the 1990s, and 44 buildings in the 2000s. The bulk samples were analyzed by using a polarizing microscope after a pre-process using a stereomicroscope in a hood with an HEPA filter. This study defined ACMs(asbestos-containing materials) as asbestos when the content percentage was over 1% in the analysis result. Methods and standards of risk assessment of asbestos-containing building materials were conducted by refering to no. 2016-230 "Method of Risk Assessment of Asbestos-Containing Buildings" from the Ministry of Environment. The risk of exposure to ACMs was rated by a score based on three categories(high, middle, low risk of asbestos exposure). Results: In this study, 30 of the 100 buildings and 36 of the 416 bulk samples(8.6%) were found to have had asbestos. Asbestos was detected at a high rate, in 18 out of 42, in buildings constructed in the 1990s and at the lowest rate(7 out of 44) for buildings constructed in the 2000s. As a result of the evaluation according to no. 2016-230 "Method of Risk Assessment of Asbestos-Containing Buildings" of the Ministry of Environment, the risk assessment level of two asbestos-containing building materials was found to be "Medium", and 28 buildings materials were found to be at the "Low" level. Conclusion: As asbestos is regulated by the government, it is required to conduct active management and implemention by introducing methods of risk assessment of asbestos exposure that are supported by data from various situations. In the case of buildings owned by individuals, building owners should be aware of the risk of exposure to asbestos.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.147-154
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• 1984

Two Fe-hydrous oxide A,B and one Al-hydroxide minerals were synthesized precipitating Fe $Cl_3$ and $AlCl_3$ with alkali solution(NaOH) at pH 6.0, 12.0 and 4.5 respectively, for precise understanding of physico-chemical and surface charge characteristics of soils in which these minerals are dominant. Identification of these final products, effect of free and amorphous materials on X-ray diffraction analysis, particle size distribution and surface change characterics of these minerals were performed. Fe-hydroxide A and B were identified as great deal of X-ray amorphous material and as goethite with large amount of X-ray amorphous material, respectively. Dehydration by oven at $105^{\circ}C$ of these minerals exhibited akaganeite peaks with low X-ray amorphous hump and pure goethite peaks for Fe-hydroxide A and B, respectively. Both minerals, however, turned into hematite upon firing at $550^{\circ}C$. On the other hand, Al-hydroxide identified as mixture of gibbsite and bayerite of around 7:3 ratio. Application of sodium dithionite and ammonium oxalate solutions for removal of free or amorphous Fe and Al from these minerals revealed that only peak intensities of Al-hydroxide system were enhanced upon Al-extraction by oxalate solution even though dithionite solution was much powerful to extract Fe from Fe-hydrous oxide systems. Original(wet) Fe-hydrous oxide A has the highest specific surface and surface charge development(negative and positive), and the greatest amount of less than $2{\mu}m$ sized particles. Specific surface and clay sized particles(less than $2{\mu}m$) of Fe-hydrous oxide A, however, were drastically reduced upon dehydration($P_2O_5$ and oven drying) compare to the rest minerals. The Z.P.C. of these synthetic minerals were 8.0-8.5, 7.5-8.0 and 5.5-6.0 for Fe-hydrous oxide A, B and Al-hydroxide, respectively.

• Molecules and Cells
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• v.21 no.1
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• pp.52-62
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• 2006

In previous reports we demonstrated that ginsenosides, active ingredients of Panax ginseng, affect some subsets of voltage-dependent $Ca^{2+}$ channels in neuronal cells expressed in Xenopus laevis oocytes. However, the major component(s) of ginseng that affect cloned $Ca^{2+}$ channel subtypes such as ${\alpha}_{1C}$(L)-, ${\alpha}_{1B}$(N)-, ${\alpha}_{1A}$(P/Q)-, ${\alpha}_{1E}$(R)- and ${\alpha}_{1G}$(T) have not been identified. Here, we used the two-microelectrode voltage clamp technique to characterize the effects of ginsenosides and ginsenoside metabolites on $Ba^{2+}$ currents ($I_{Ba}$) in Xenopus oocytes expressing five different $Ca^{2+}$ channel subtypes. Exposure to ginseng total saponins (GTS) induced voltage-dependent, dose-dependent and reversible inhibition of the five channel subtypes, with particularly strong inhibition of the ${\alpha}_{1G}$-type. Of the various ginsenosides, $Rb_1$, Rc, Re, Rf, $Rg_1$, $Rg_3$, and $Rh_2$, ginsenoside $Rg_3$ also inhibited all five channel subtypes and ginsenoside $Rh_2$ had most effect on the ${\alpha}_{1C}$- and ${\alpha}_{1E}$-type $Ca^{2+}$ channels. Compound K (CK), a protopanaxadiol ginsenoside metabolite, strongly inhibited only the ${\alpha}_{1G}$-type of $Ca^{2+}$ channel, whereas M4, a protopanaxatriol ginsenoside metabolite, had almost no effect on any of the channels. $Rg_3$, $Rh_2$, and CK shifted the steady-state activation curves but not the inactivation curves in the depolarizing direction in the ${\alpha}_{1B}$- and ${\alpha}_{1A}$-types. These results reveal that $Rg_3$, $Rh_2$ and CK are the major inhibitors of $Ca^{2+}$ channels in Panax ginseng, and that they show some $Ca^{2+}$ channel selectivity.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.336-343
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• 2000

Purpose: Thallous-201 chloride produced at Korea Cancer Center Hospital(KCCH) is used in detecting cardiovascular disease and cancer. Thallium impurity can cause emesis, catharsis and nausea, so the presence of thallium and other metal impurities should be determined. According to USP and KP, their amounts must be less than 2 ppm in thallium and 5 ppm in total. In this study, the detection method of trace amounts of metal impurities in $[^{201}Tl]$TICI injection with polarography was optimized without environmental contamination. Materials and Methods: For the detection of metal impurities, Osteryoung Square Wave Stripping Voltammetry method was used in Bio-Analytical System (BAS) 50W polarograph. The voltammetry was composed of Dropping Mercury Electrode (DME) as a working electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode. Square wave stripping method, which makes use of formation and deformation of amalgam, was adopted to determine the metal impurities, and pH 7 phosphate buffer was used as supporting electrolyte. Results: Tl, Cu and Pb in thallous-201 chloride solution were detected by scanning from 300 mV to -800 mV Calibration curves were made by using $TINO_3,\;CuSO_4\;and\;Pb(NO_3){_2}$ as standard solutions. Tl was confirmed at -450 mV peak potential and Cu at -50 mV Less than 2 ppm of Tl and Cu was detected and Pb was not detected in KCCH-produced thallous-201 chloride injection. Conclusion: Detection limit of thallium and copper is approximately 50 ppb with this method. As a result of this experiment, thallium and other metal impurities in thallous-201 chloride injection, produced at Korea Cancer Center Hospital, are in the regulation of USP and KP Polarograph could be applied for the determination of metal impurities in the quality control of radiopharmaceuticals conveniently without environmental contamination.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.59-67
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• 1995

Blood lead assay by $D_2$ lamp background correction method of atomic absorption spectrophotometer(AAS) with wavelength of 283.3 nm is most popular in occupational health practice in Korea. On the other hand, $D_2$ lamp background correction method with wavelength of 217.0 nm is also often used in general chemical analysis for lead assay in general purpose. But both methods have some weakness of background correction which brought direct effect on the results of analysis. Recently blood lead assay with polarized Zeeman effect of AAS was introduced and is now preferred in many laboratory than $D_2$ correction method in blood lead analysis. But still AAS with $D_2$ lamp are widely used in the field of occupational health in Korea. This study compared blood lead assay data with $D_2$ correction methods(283.3 and 217.0 nm) and with that of polarized Zeeman effect correction method to evaluate the validity of 02 correction methods. The results obtained were as follows; 1. Taking the value of polarized Zeeman effect method as reference value of 1.00, the mean relative value of $D_2$ correction method with wavelength of 217.0 nm was 0.92 and that with wavelength of 283.3 nm was 0.90 respectively in the analysis of blood lead whose value were below $20.0{\mu}g/dl$(p<0.001). Both mean values were statistically smaller than polarized Zeeman effect correction method. But in the analysis of blood whose value were between 20.0 to $20.0{\mu}g/dl$, the mean relative value of $D_2$ correction method was 0.96 in both wavelength and did not differ from polarized Zeeman effect method(p<0.001). There was no difference of blood lead between $D_2$ correction method and polarized Zeeman effect method in the analysis of blood lead whose value were over $40.0{\mu}g/dl$. 2. The variations of background correction value in polarized Zeeman effect method were not changed by increase of blood lead, but those in $D_2$ correction methods were increased by the increase of blood lead. While then relative standard deviation(RSD) of data measured by Zeeman effect method were decreased by the increase of blood lead, those by $D_2$ methods were nol differed by the increase of blood lead.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.104-110
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• 2013

This study assessed hazards at the harvest stage of strawberry farms which may cause risk to humans. A total of 216 samples were collected from 6 strawberry farms (soil culture farms: A, B, C; nutriculture farms: D, E, F) located in Western Gyeongnam. The collected samples were subjected for sanitary indicator bacteria (aerobic plate count, coliforms and Escherichia coli), major foodborne pathogens (E. coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and Bacillus cereus), and fungi. The levels of APC and coliform in the soil culture farms were 1.0-6.9 and 0.4-4.6 log CFU/g (leaf, mL, hand or 100 $cm^2$), respectively. The samples obtained from the nutriculture farms were contaminated with the levels of 0.8-4.9, and 0.2-2.6 log CFU/g (leaf, mL, hand or 100 $cm^2$) of APC and coliform. However, E. coli was not detected in any samples. In major foodborne pathogens, S. aureus was detected at the level of ${\leq}$3.3 log CFU/hand in workers' hand samples and B. cereus was detected at the levels of 0.4-4.1 log CFU/g (hand or 100 $cm^2$) in soil, plants and workers' hygiene. L. monocytogenes, E. coli O157:H7 and Salmonella spp. were not detected. Fungi were detected at the levels of 1.0-5.2 and 0.2-4.4 log CFU/g (leaf, mL, hand or 100 $cm^2$) in soil culture and nutriculture farms, respectively.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.977-983
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• 2002

This study was performed to establish the precise and rapid method to distinguish croakers through the pigment analysis of colored imported white croakers for adultration. We surveyed the coloring behaviors, extraction test by water and organic solvent and using pigments such as targeting, curcumine, and azo dye products. The pigment of yellow croaker is not stained on wet cloth or tissue which is rubbed on epidermis of yellow croaker and was not eluted in water extraction test, while adulterated pigments were easily extracted by water and acetone, but edible diluted yellow, Yellow No. 4 and Yellow No. 5 were not extracted. Reactive pigment was detected easily by extraction with water and dispersed pigment was also detected by extraction test. As a result of discoloring characteristics of carotene having similar structure to yellow croaker and azo dye by oxidation and reduction, azo dyes were not discolored by oxidation with sodium percarbonate or peracetic acid but that were discolored by oxidation with Fenton reagent after 1hr and by hypochlorite promptly. On the other hand, carotenes were not discolored by sodium precarbonate and Fenton reagent but discolored by sodium hypochlorite after 2 hr and by peracetic acid promptly. Azo dyes were discolored by reduction with sodium hydrosulfite and sodium carbonate but carotenes were not discolored by these reagents. This discoloring test was applicable to detect adulterated pigments and other marine product.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1278-1284
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• 2000

The study was performed to elucidate the effects of ethylene-absorbent on the quality of 'Fuyu' persimmon fruits in the MA package. Five persimmons were packed in a MA package film (low density polyethylene, 0.055 mm film thickness), and stored at $-0.5^{\circ}C$ for 60 days. Two persimmons were repacked in a MA package with or without ethylene absorbent $(1\;M\;KMnO_4+zeolite)$ and stored at $-0.5^{\circ}C$. Ten days later, these packages was moved to $2^{\circ}C$ or $25^{\circ}C$ storage room to examine the effect of the ethylene-absorbent on the quality of the fruits. Ethylene removal by enclosed ethylene absorbent in MA packaging reduced the rate of fruit respiration at $25^{\circ}C$, so that $O_2$ and $CO_2$ concentration in packing were maintained higher and lower, respectively, compared to control. These effects were not observed, however, in $2^{\circ}C$ post-storage. Fruit firmness and sugar composition were also influenced by ethylene absorbent, showing more delayed flesh softening and higher sucrose concentration in ethylene absorbent treated fruits than control. But ethylene-absorbent treatment lowered glucose and fructose concentration. That shows that ethylene could influence on sugar composition by inhibiting sucrose inversion to glucose and fructose. The production of ethanol and acetaldehyde was reduced by ethylene removal, but the effect was not so high as other quality indices.