• Clean Technology
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• v.29 no.2
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• pp.126-134
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• 2023

Direct catalytic decomposition is a promising method for controlling the emission of nitrous oxide (N₂O) from the semiconductor and display industries. In this study, a γ-Al₂O₃ catalyst was developed to reduce N₂O emissions by a catalytic decomposition reaction. The γ-Al₂O₃ catalyst was prepared by an extrusion method using boehmite powder, and a N₂O decomposition test was performed using a catalyst reactor that was approximately 25.4 mm (1 in) in diameter packed with approximately 5 mm of catalysts. The N₂O decomposition tests were carried out with approximately 1% N₂O at 550 to 750 ℃, an ambient pressure, and a GHSV=1800-2000 h^-1. To confirm the N₂O decomposition properties and the effect of O₂ and steam on the N₂O decomposition, nitrogen, air, and air and steam were used as atmospheric gases. The catalytic decomposition tests showed that the 1% N₂O had almost completely disappeared at 700 ℃ in an N₂ atmosphere. However, air and steam decreased the conversion rate drastically. The long term stability test carried out under an N₂ atmosphere at 700 ℃ for 350 h showed that the N₂O conversion rate remained very stable, confirming no catalytic activity changes. From the results of the N₂O decomposition tests and long-term stability test, it is expected that the prepared γ-Al₂O₃ catalyst can be used to reduce N₂O emissions from several industries including the semiconductor, display, and nitric acid manufacturing industry.

• Applied Biological Chemistry
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• v.11
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• pp.1-27
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• 1969

More than thirty kinds of sea food pickles have been eaten in Korea. Out of these salted yellow tail pickle, salted clam pickle, salted oyster pickle, and salted cuttlefish pickle were employed for the analysis of their components, identification of main fermenting microbes, and determination of enzyme characteristics concerned. Also studied was the effect of enzymic action of microbes, which are concerned with the fermenting of pickles, on the production of flavorous 5'-mononucleotides and amino acids. The results are summarized as follows: 1. Microflora observed in the pickles are: (a) Total count of viable cells after 1-2 months of pickling was found to be $10^7$ and that after 6 months decreased to $10^4$. (b) Microbial occurence in the early stage of pickling was observed to be 10-20% Micrococcus spp., 10-20% Brevibacterium spp., 0-30% Sarcina spp., 20-30% Leuconostoc spp., ca 30% Bacillus spp., 0-10% Pseudomonas spp., 0-10% Flavobacterium spp., and 0-20% yeast. (c) Following the early stage of pickling, mainly halophilic bacteria such as Bacillus subtilis, Leuconostoc mesenteroides, Pediococcus halophilus and Sarcina litoralis, were found to exhibit an effect on the fermentation of pickle and their enzyme activities were in direct concern in fermentation of pickles. (d) Among the bacteria participating in the fermentation, Sarcina litoralis 8-14 and 8-16 strains were in need of high nutritional requirement and the former was grown only in the presence of purine, pyrimidine and cystine and the latter purine, pyrimidine and glutamic acid. 2. Enzyme characteristics studied in relation to the raw materials and the concerned microbes isolated are as follows: (a) A small amount of protease was found in the raw materials and 30-60% decrease in protease activity was demonstrated at 7% salt concentration. (b) Protease activity of halophilic bacteria, Bacillus subtilis 7-6, 11-1, 3-6 and 9-4 strains, in the complete media decreased by 10-30% at the 7% salt concentration and that of Sarcina litoralis 8-14 and 8-16 strains decreased by 10-20%. (c) Proteins in the raw materials were found to be hydrolyzed to yield free amino acids by protease in the fermenting microbes. (d) No accumulation of flavorous 5'-mononucleotides was demonstrated because RNA-depolymerase in the raw materials and the pickles tended to decompose RNA into nucleoside and phosphoric acid. (e) The enzyme produced in Bacillus subtilis 3-6 strain isolated from the salted clam pickles, was ascertained to be 5'-phosphodiesterase because of its ability to decompose RNA and thus accumulating 5'-mononucleotide. (f) It was demonstrated that the activity of phosphodiesterase in Bacillus subtilis 3-6 strain was enhanced by some components in the corn steep liquor and salted clam pickle. The enzyme activity was found to decrease by 10-30% and 40-60% at the salt concentration of 10% and 20%, respectively. 3. Quantitative data for free amino acids in the pickles are as follows: (a) Amounts of acidic amino acids such as glutamic and aspartic acids in salted clam pickle, were observed to be 2-10 times other pickles and it is considered that the abundance in these amino acids may contribute significantly to the specific flavor of this food. (b) Large amounts of basic amino acids such as arginine and histidine were found to occur in salted yellow tail pickle. (c) It is much interesting that in the salted cuttlefish pickle the contents of sulfur-containing amino acids were exceedingly high compared with those of others: cystine was found to be 17-130 times and methionine, 7-19 times. (d) In the salted oyster pickle a high content of some essential amino acids such as lysine, threonine, isoleucine and leucine, was demonstrated and a specific flavor of the pickle was ascribed to the sweet amino acids. Contents of alanine and glycine in the salted oyster pickle were 4 and 3-14 times as much as those of the others respectively. 4. Analytical data for 5'-mononucleotides in the pickles are as follows: (a) 5'-Adenylic acid and 3'-adenylic acid were found in large amounts in the salted yellow tail pickle and 5'-inosinic acid in lesser amount. (b) 5'-Adenylic acid, especially 3'-adenylic acid predominated in amount in the salted oyster pickle over that in the other pickles. (c) The salted cuttlefish pickle was found to contain only 5'-adenylic acid and 3'-adenylic acid. It has become evident from the above fact that clam and the invertebrate lack of adenylic deaminase and contain high content of adenylic acid. Thus, they were demonstrated to be the AMP-type. (d) 5'-Inosinic acid was contained in the salted yellow tail pickle in a significant concentration, and it might be considered to be IMP-type. 5. Comparative data for flavor with regard to the flavorous amino acids and the contents of 5'-mononucleotides are: (a) A specific flavor of salted yellow tail pickle was ascribed to the abundance in glutamic acid and aspartic acid, and to the existence of a small amount of flavorous 5'-inosinic acid. The combined effect of these components was belived to exhibit a synergistic action in producing a specific fiavor to the pickle. (b) A specific flavor of salted clam pickle has been demonstrated to be attributable to the richness in glutamic acid and aspartic acid rather than to that of 5'-mononucleotides.

• Journal of Aquaculture
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• v.5 no.1
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• pp.29-67
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• 1992

Life cycle and seed production of the freshwater prawn, Macrobrachium nipponense, were studied and the results are as follows : 1. Larval development : Embryos hatched out as zoea larvae of 2.06 mm in mean body length. The larvae passed through 9 zoea stages in $15{\~}20$ days and then metamorphosed into postlarvae measuring 5.68 mm in mean body length. Each zoea stage can be identified based on the shapes of the first and second antennae, exo- and endopodites of the first and second pereiopods, telson and maxillae. 2. Environmental requirements of zoea larvae : Zoea larvae grew healthy when fed with Artemia nauplii. Metamorphosing rate was $65{\~}72{\%}$ at $26{\~}28\%$ and $7.85{\~}8.28\%_{\circ}Cl.$. The relationship between the zoeal period (Y in days) and water temperature (X in $^{\circ}C$) is expressed as Y=46.0900-0.9673X. Zoeas showed best survival in a water temperature range of $26{\~}32^{\circ}C$ (optimum temperature $28^{\circ}C$), at which the metamorphosing rate into postlarvae was $54{\~}72\%$ The zoeas survived more successfully in chlorinity range of $4.12{\~}14.08{\%_{\circ}}Cl.$, (optimum chlorinity $7.6{\~}11.6\;{\%_{\circ}}Cl.$.), at which the metamorphosing rate was $42{\~}76{\%}$. The whole zoeal stages tended to be longer in proportion as the chlorinity deviated from the optimum range and particularly toward high chlorinity. Zoeas at all stages could not tolerate in the freshwater. 3. Environmental requirements of postlarvae and juveniles : Postlarvae showed normal growth at water temperatures between $24{\~}32^{\circ}C$ (optimun temperature $26{\~}28^{\circ}$. The survival rate up to the juvenile stage was $41{\~}63{\%}$. Water temperatures below $24^{\circ}C$ and above $32^{\circ}$ resulted in lower growth, and postlarvae scarcely grew at below $17^{\circ}C$. Cannibalism tended to occur more frequently under optimum range of temperatures. The range of chlorinity for normal growth of postlarvae and juveniles was from 0.00 (freshwater) to $11.24{\%_{\circ}}Cl.$, at which the survival rate was $32{\~}35\%$. The postlarvae grew more successfully in low chlorinities, and the best growth was found at $0.00\~2.21{\%_{\circ}}Cl.$. The postlarvae and juveniles showed better growth in freshwater but did not survive in normal sea water. 4. Feeding effect of diet on zoea Ilarvae : Zoea larvae were successfully survived and metamorposed into postlarvae when fed commercial artificial plankton, rotifers, and Artemia nauplii in the aquaria. However, the zoea larvae that were fed Artemia nauplii and reared in Chlorella mixed green water showed better results. The rate of metamorphosis was $68\~{\%}75$. The larvae fed cow live powder, egg powder, and Chlorella alone did not survive. 5. Diets of postlarvae, juveniles and adults : Artemia nauplii and/or copepods were good food for postlarvae. Juveniles and adults were successfully fed fish or shellfish flesh, annelids, corn grain, pelleted feed along with viscera of domestic animals or fruits. 6. Growth of postlarvae, juveniles and adults : Under favorable conditions, postlarvae molted every five or six days and attained to the juvenile stage within two months and they reached 1.78 cm in body length and 0.17 g in body weight. The juveniles grew to 3.52 cm in body length and 1.07 g in body weight in about four months. Their sexes became determinable based on the appearance of male's rudimental processes (a secondary sex character) on the endopodites of second pereiopods of males. The males commonly reached sexual maturity in seven months after attaining the postlarvae stage and they grew to 5.65 cm in body length and 3.41 g in body weight. Whereas the females attained sexual maturity within six to seven months, when they measured 4.93 cm in body length and 2.43 g in body weight. Nine or ten months after hatching, the males grew $6.62{\~}7.14$ cm in body length and $6.68{\~}8.36$ g in body weight, while females became $5.58{\~}6.08$ cm and $4.04{\~}5.54$ g. 7. Stocking density : The maximum stocking density in aquaria for successful survival and growth was $60{\~}100$ individuals/$\ell$ for zoeas in 30-days rearing (survival rate to postlarvae, $73{\~}80{\%}$) ; $100{\~}300$ individuals/$m^2$ for postlarvae of 0.57 cm in body length (survival rate for 120 days, $78{\~}85{\%}$) ; $40{\~}60$ individuals/$m^2$ for juveniles of 2.72 cm in body length (survival rate for 120 days, $63{\~}90{\%}$) : $20{\~}40$ individuals/$m^2$ for young prawns of 5.2 cm in body length (survival rate for 120 days, $62\~90{\%}$) ; and $10\~30$ individuals/$m^2$ for adults of 6.1 cm in body length (survival rate for 60 days, $73\~100{\%}$). The stocking density of juveniles, youngs and adults could be increased up to twice by providing shelters.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.66-80
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• 1977

This research was carried as a part of the basic study, in which the aptitude of theKorean oak varieties as barrels for aging apple fine spirits was investigated, and thefollowing results were obtained. 1. Following was the result of the chemical analysis of the fruits which are now mass-produced and can be used as a substitute for raw materials for wine production. Apple (Malus pumila Miller var. domestica Schneider) : Total sugar. total acid, volatile acid and pectin of Jonathan (Hong-og) were 13.95%, 0.46%, 0.012%, 0.20% respectively. Total sugar, total acid, volatile acid and pectin of Ralls (Koog-kwang) were 13.35%, 0.43%, 0.011%, 0.45% respectively. 2. Because of low yield of apple juice due to cellulose, pectin, hemicellulose which are present besides sugars, acids in apples, the apple juice were treated with xylanase of Aspergillus niger SUAFM-430, cellulase and pectinase of Aspergillus niger SUAFM-6. This treatment increased the yield of apple juice. And the apple juice was sterilized by adding potassium metabisulfite $(K_2S_20_5)$ and Saccharomyces cerevisae var. ellipsoideus Rasse Johannisberg II (SUAFM-1018) as a cultivation yeast, which has a strong fermentation power was used to ferment. The yield of apple wine based on raw material was 86-87%. The amount of ethanol, extract and methanol obtained from Jonathan and Ralls were 13.5%, 5.4%, 0.04-0.05% respectively. 3. Wines were distilled for two times by the pot still method to make fine spirits. The yield of fine spirits from apple wine mash was 86.6%, and the pH of fine spirits from Jonathan and Ralls were 4.1, 4.2 respectively. 4. The oak chips made of inner part or outer part of 24 Korean oak varieties were used to select the barrel for aging fine spirits. Two oak chips (one oak chip: $1{\times}1{\times}5cm$) of the inner part or of the outer part of each oak variety were dipped into 300 ml of fine spirits, which was bottled in 640ml beer bottle, and followed aging. The colors, flavors and tastes of the fine spirits were checked during 6 months. A. As a criterion for the first screening of oak barrels for aging fine spirits, the rate five of color extraction was determined. The oak chips showed good results in their order as follows and the best 5 varieties were selected. Gal-cham: Quercus aliena Blume (Inner part), Gul-cham: Quercus variabilis Blume (Outer part), Gal-chain: Quercus aliena Blume (Outer part), Jol-cham: Quercus serrata Thumb (Inner and Outer part). Sin-gal-cham: Quercus mongolica Fisher (Outer and Inner part) Sang-su-ri: Quercus acutissima Carruthers (Outer and Inner part) B. To find out the influence of aging temperature on aging, apple fine spirits were aged by dipping each oak chip at room temperature $(24-25^{\circ}C)$) and $45^{\circ}C$. Aging at $45^{\circ}C$ gave the best result followed aging at $30^{\circ}C$ and then at room temperature. C. Apple fine spirits was aged for six months by dipping oak chips in Erlenmeyer flasks and was irradiated with U.V light. The U.V irradiation enhanced the aging effect by nearly two times, compared with the aging without U.V irradiation. D. In aging apple fine spirits by dipping two oak chips, it was observed that the extent of the extraction of most components of oak chips were strongly dependent upon the pH of fine spirits. E. Oak chips of five selected oak varieties and a Limousin white oak from France as a control were used. Each apple fine spitits was dipped by two oak chips, and was aged at room temperature $(24-25^{\circ}C)$, $30^{\circ}C$, $45^{\circ}C$, and with the U.V irradiation at room temperature shaking every week. After six months of aging, the panel test of these aged fine spirits (Young Brandy) showed the following result. Young brandy of apples aged at $45^{\circ}C$ by dipping oak chips of Gal-chain was almost as the fine spirits which were aged at room temperature by dipping Limousin white oak chips from France. Young brandy of with U.V. irradiation at room temperature which were aged by dipping oak chips of Gal-chain was a little worse than that from the fine spirits aged at room temperature by dipping Limousin white oak chips from France. And so, Korean oak varieties are thought to be able to be used for aging every apple fine spirit which was here investigated.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.273-284
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• 1996

Embryos and fetuses are more sensitive to various environmental agents than are adults or children. The biological effects such as intrauterine death and malformation are closely connected with prenatal exposure very various agents. The sensitivity of these embryonic/fetal effects depends on the stage of pregnancy. From the viewpoint of fetal development, embryonic and fetal stages can be divided into three stages : Preimplantation, organogenetic and fetal. Each stage corresponds to 0 to 4.5days, 4.5 to 13.5days, and 13.5days of gestation in mice, respectively. Many studies on the biologcal effects of mice irradiated by ${\gamma}-rays$ at various stages during organogenesis and fetal period have been performed. Based on these results, the dose-effect and dose-response relationships in malformations, intrauterine death, or retardation of the physical growth have been practically modeled by the ICRP(International Commission on Radiological Protection) and other international bodies for radiation protection. Many experimental studies on mice have made it clear that mice embryos in the preimplantation period have a higher sensitivity to radiation for lethal effects than the embryos/fetuses on other prenatal periods. However, no eratogenic effects of radiation at preimplantation stages of mice have been described in many textbooks. It has been believed that 'all or none action results' for radiation of mice during the preimplantation period were applied. The teratogenic and lethal effects during the preimplantation stage are one of the most important problems from the viewpoint of radiological protection, since the preimplantation stage is the period when the pregnancy itself is not noticed by a pregnant woman. There are many physical or chemical agents which affect embryos/fetuses in the environment. It is assumed that each agents indirectly effects a human. Then, a safety criterion on each agent is determined independently. The pregnant ICR mice on 2, 48, 72 or 96 hours post-conception (hpc), at which are preimplantation stage of embryos, were irradiated whole body Cesium-gamma radiation at doses of 0.1, 0.25, 0.5, 1.5, and 2.5 Gy with dose rate of 0.2 Gy/min. In the embryos from the fetuses from the mice irradiated at various period in preimplantation, embryonic/fetal mortalities, incidence of external gross malformation, fetal body weight and sex ratio were observed at day 18 of gestation. The sensitivity of embryonic mortalities in the mice irradiated at the stage of preimplantation were higher than those in the mice irradiated at the stage of organogenesis. And the more sensitive periods of preimplantation stage for embryonic death were 2 and 48 hpc, at which embryos were one cell and 4 to 7 cell stage, respectively. Many types of the external gross malformations such as exencephaly, cleft palate and anophthalmia were observed in the fetuses from the mice irradiated at 2, 72 and 96 hpc. However, no malformations were observed in the mice irradiated at 48 hpc, at which stage the embryos were about 6 cell stage precompacted embryos. So far, it is believed that the embryos on preimplantation stage are not susceptible to teratogens such as radiation and chemical agents. In this study, the sensitivity for external malformations in the fetuses from the mice irradiated at preimplantation were higher than those in the fetuses on stage of organogenesis.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.133-137
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• 2000

Purpose :To investigate whether combined beta-carotene with X-Irradiation has more enhanced radition response than X-irradiation or not, we peformed a experiment about in vitro cytotoxlcity of beta-carotene and/or X-irradiation in the fibrosarcoma cells, tumor growth delay of combined beta-caroten with/or X-irradiation in the mouse fibrosarcoma. Materials and Methods : 2$\%$ emulsion of beta-carotene was serially diluted and used. X-Irradiation was given by 6 MeV linear accelerator. The cytotoxicity of beta-carotene in vitro was evaluated from clonogenic assay. To compare the cytotoxiclty between combined beta-carotene with X-irradiation and X-irradiation group, 2 mg/ml of beta-carotene was contacted to fibrosarcoma (FSall) cells for 1 hour before X-irradiation. For the tumor growth delay, single 20 Gy was given to FSall tumor hearing C3H/N mice whic was classified as beta-crotene with X-irradiation group (n=5) and X-irradiation alone group (n=5). 0.2 ml of 20 mg/kg of beta-carotene were i.p. injected to mice 30 minute before X-irradiation in the beta-crotene with X-irradiation group. The tumor growth delay defined as the time which reach to 1,000 mm$^{3}$ of tumor volume. Results : (1) Cytotoxicity in vitro: 1) survival fraction at beta-carotene concentration of 0.002,0.02,0.2 and 2 mg/ml were 0.69$\pm$0.07, 0.59$\pm$0.08, 0.08$\pm$0.008 and 0.02$\pm$0.006, respectively. 2) each survival fraction at 2, 4, 6 and 8 Gy in the 2 mg/ml of beta-carotene + X-irradiation group were 0.13$\pm$0.05, 0.03$\pm$0.005, 0.01 $\pm$0.002 and 0.009$\pm$0.0008, respectively. But each survival fraction at same irradiation dose in the X-irradiation group were 0.66$\pm$0.05, 0.40$\pm$0.04, 0.11$\pm$0.01 and 0.03$\pm$0.006, respectively(p<0.05). (2) The time which reach to 1,000 mm$^{3}$ of tumor volume of beta-carotene + X-irradiation group and X-irradiation alone group were 18, 19 days, respectively(p>0.05) Conclusion : The contact of beta-caroten to Fsall cells showed mild cytotoxicity which 띤as increased according to concentration. The cytotoxicity of combined beta-carotene with X-irradiation more increased than that of X-irradiation, additionally, And there was significant difference of cytotoxicity between two groups. But there were no significant difference of the growth delay of fibrosarcoma between two groups.

• Radiation Oncology Journal
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• v.20 no.4
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• pp.343-352
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• 2002

Purpose : Radiotherapy is the main treatment modality for uterine cervix cancer. Since the rectum is in the radiation target volume, rectal bleeding is a common late side effect. This study evaluates the risk factors of radiation induced rectal bleeding and discusses its optimal management. Materials and Methods : total of 213 patients who completed external beam radiation therapy (EBRT) and intracavitary radiation (ICR) between September 1994 and December 1999 were included in this study. No patient had undergone concurrent chemo-radiotherapy. Ninety patients received radiotherapy according to a modified hyperfractionated schedule. A midline block was placed at a pelvic dose of between 30.6 Gy to 39.6 Gy. The total parametrial dose from the EBRT was 51 to 59 Gy depending on the extent of their disease. The Point A dose from the HDR brachytherapy was 28 Gy to 30 Gy $(4\;Gy\times7,\;or\;5\;Gy\times6)$. The rectal point dose was calculated either by the ICRU 38 guideline, or by anterior rectal wall point seen on radiographs, with barium contrast. Rectal bleeding was scored by the LENT/SOMA criteria. For the management of rectal bleeding, we opted for observation, sucralfate enema or coagulation based on the frequency or amount of bleeding. The median follow-up period was 39 months $(12\~86\;months)$. Results : The incidence of rectal bleeding was $12.7\%$ (27/213); graded as 1 in 9 patients, grade 2 in 16 and grade 3 in 2. The overall moderate and severe rectal complication rate was $8.5\%$. Most complications $(92.6\%)$ developed within 2 years following completion of radiotherapy (median 16 months). No patient progressed to rectal fistula or obstruction during the follow-up period. In the univariate analysis, three factors correlated with a high incidence of bleeding an icruCRBED greater than 100 Gy $(19.7\%\;vs.\;4.2\%)$, an EBRT dose to the parametrium over 55 Gy $(22.1\%\;vs.\;5.1\%)$ and higher stages of III and IV $(31.8\%\;vs.\;10.5\%)$. In the multivariate analysis, the icruCRBED was the only significant factor (p>0.0432). The total parametrial dose from the EBRT had borderline significance (p=0.0546). Grade 1 bleeding was controlled without further management (3 patients), or with sucralfate enema 1 to 2 months after treatment. For grade 2 bleeding, sucralfate enema for 1 to 2 months reduced the frequency or amount of bleeding but for residual bleeding, additional coagulation was peformed, where immediate cessation of bleeding was achieved (symptom duration of 3 to 10 months). Grade 3 bleeding lasted for 1 year even with multiple transfusions and coagulations. Conclusion : Moderate and several rectal bleeding occurred in $8.5\%$ of patients, which is comparable with other reports. The most significant risk factor for rectal bleeding was the accumulated dose to the rectum (icruCRBED), which corrected with consideration to biological equivalence. Prompt management of rectal bleeding, with a combination of sucralfate enema and coagulation, reduced the duration of the symptom, and minimized the anxiety/discomfort of patients.

• Journal of Mushroom
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• v.11 no.4
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• pp.230-239
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• 2013

The major species of fungus gnats which caused the severe damage in shiitake farm were identified as a Bradysia difformis, B. alpicola, and Camtomyia cortocalis on oak log beds cultivation. The B. difformis occurred early in the middle of March while B. alpicola and C. cortocalis appeared since the beginning of May. The occurrence rate for adults of B. difformis showed highly at the end of July (11.9~1,774.2 in dong-myeon and 0.4~2,583.3 in pungse-myeon) in 2012 and mid-June (10.7~4,650 in dong-myeon and 36.8~4740 in pungse-myeon) in 2013. The counting numbers on the traps for B. alpicola reached highest peak in the middle of June (2.1~63.2 in dong-myeon and 1.0~21.7 in pungse-myeon) and the end of May (0.8~163.7 in dong-myeon and 0.5~280.5 in pungse-myeon) in 2012 and 2013, respectively. The number of C. cortocalis showed high record in the middle of May in 2012 (0.6~4.7) and in the middle of June (2.1~17.3) in 2013 in dong-myeon whereas showed the peaks in the middle of May (0.6~4.7) in 2012 and in the late of May (1.3~17.6) in 2013 in pungse-myeon. The fruiting bodies of shiitake mushroom by fungus gnats were severely damaged from mid-June to late-July and the damage rate were 0.625.5% (2012) and 0.7~30.5% (2013) in dong-myeon and 1.5%~21.6% (2012) and 1.9~36.8%(2012) in pungse-myeon. To investigate the control effect for fungus gnats by Hypoaspis aculeifer, H. aculeifer (30 mixutre of nymph and adult per $m^2$) were treated to oak log beds shiitake cultivation for six times (May 2 and 28, June 25, July 10 and 25 and August 28). The occurrence rate of adults and damage rate of fruiting bodies of 3 major species reduced 79.3% (adult numbers) and 74.8% (fruiting bodies) in dong-myeon and 64.1% (adult numbers) and 65.5% (fruiting bodies) in pungse-myeon, respectively, compared to non-treatment. Accordingly, H. aculeifer effectively controlled the fungus gnats on shiitake mushroom and can be used as good control agent.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.8-15
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• 1995

The reliable measurement of metal in biological media in human body is one of critical indicators for the proper evaluation of its toxic effect on human health. Recently in Korea the necessity of quality assurance of measurement in occupational health and occupational hygiene fields brought out regulatory quality control program. Lead is often used as a standard metal for the program in both fields of occupational health and hygiene. During last 20 years lead poisoning was prevalent in Korea and still is one of main heavy metal poisoning and the capability of the measurement of blood lead is one of prerequisites for institute of specialized occupational health in Korea. Furthermore blood lead is most important indicator to evaluate lead burden of human exposure to lead and the reliable and accurate analysis is most needed whenever possible. To evaluate the extent of the interlaboratory differences of blood lead measurement in several well-known institute specialized in occupational health in Korea, authors prepared 68 blood samples from two storage battery industries and all samples were divided into samples with 2 ml. One set of 68 samples were analyzed by authors's laboratory(Soonchunhyang University Institute of Industrial Medicine: SIIM) and 40 samples of other set were analyzed by C University Institute of Industrial Medicine(CIIM) and the rest 28 samples of other set were analyzed by Japanese institute(K Occupational Health Center:KOHC). Authors also prepared test bovine samples which were obtained from Japanese Federation of Occupational Health Organization (JFOHO) for quality control. Authors selected 2 other well-known occupational health laboratories and one laboratory specialized for instrumental analysis. A total of 6 laboratories joined the interlaboratory comparison of blood lead measurement and the results obtained were as follows: 1. There was no significant difference in average blood lead between SIIM and CIIM in different group of blood lead concentration, and the relative standard deviation of two laboratories was less than 3.0%. On the other hand, there was also no significant difference of average blood lead between SIIM and KOHC with relative standard deviation of 6.84% as maximum. 2. Taking less than 15% difference of mean or less than 6 ug/dl difference in below 40 ug/dl in whole blood as a criteria of agreement of measurement between two laboratories, agreement rates were 87.5%(35/40) and 78.6%(22/28) between SIIM and CIIM, SIIM and KOHC respectively. 3. The correlation of blood lead between SIIM and CIIM was 0.975 (p=0.0001) and the regression equation was SIIM = 2.19 + 0.9243 ClIM, whereas the correlation between SUM and KOHC was O.965(p=0.0001) with the equation of SIIM = 1.91 + 0.9794 KOHC. 4. Taking the reference value as a dependent variable and each of 6 laboratories's measurement value as a independent variable, the determination coefficient($R^2$) of simple regression equations of blood lead measurement for bovine test samples were very high($R^2>0.99$), and the regression coefficient(${\beta}$) was between 0.972 and 1.15 which indicated fairly good agreement of measurement results.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1265-1276
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• 1998

Background : Nitric oxide(NO) is an endogenously produced free radical that plays an important role in regulating vascular tone, inhibition of platelet aggregation and white blood cell adhesion to endothelial cells, and host defense against infection. The highly reactive nature of NO with oxygen radicals suggests that it may either promote or reduce oxidant-induced cell injury in several biological pathways. Oxidant injury and interactions between pulmonary vascular endothelium and leukocytes are important in the pathogenesis of acute lung injury, including acute respiratory distress syndrome(ARDS). In ARDS, therapeutic administration of NO is a clinical condition providing exogenous NO in oxidant-induced endothelial injury. The role of exogenous NO from NO donor or the suppression of endogenous NO production was evaluated in oxidant-induced endothelial injury. Method : The oxidant injury in cultured rat lung microvascular endothelial cells(RLMVC) was induced by hydrogen peroxide generated from glucose oxidase(GO). Cell injury was evaluated by $^{51}$chromium($^{51}Cr$) release technique. NO donor, such as S-nitroso-N-acetylpenicillamine(SNAP) or sodium nitroprusside(SNP), was added to the endothelial cells as a source of exogenous NO. Endogenous production of NO was suppressed with N-monomethyl-L-arginine(L-NMMA) which is an NO synthase inhibitor. L-NMMA was also used in increased endogenous NO production induced by combined stimulation with interferon-$\gamma$(INF-$\gamma$), tumor necrosis factor-$\alpha$(TNF-$\alpha$), and lipopolysaccharide(LPS). NO generation from NO donor or from the endothelial cells was evaluated by measuring nitrite concentration. Result : $^{51}Cr$ release was $8.7{\pm}0.5%$ in GO 5 mU/ml, $14.4{\pm}2.9%$ in GO 10 mU/ml, $32.3{\pm}2.9%$ in GO 15 mU/ml, $55.5{\pm}0.3%$ in GO 20 mU/ml and $67.8{\pm}0.9%$ in GO 30 mU/ml ; it was significantly increased in GO 15 mU/ml or higher concentrations when compared with $9.6{\pm}0.7%$ in control(p < 0.05; n=6). L-NMMA(0.5 mM) did not affect the $^{51}Cr$ release by GO. Nitrite concentration was increased to $3.9{\pm}0.3\;{\mu}M$ in culture media of RLMVC treated with INF-$\gamma$ (500 U/ml), TNF-$\alpha$(150 U/ml) and LPS($1\;{\mu}g/ml$) for 24 hours ; it was significantly suppressed by the addition of L-NMMA. The presence of L-NMMA did not affect $^{51}Cr$ release induced by GO in RLMVC pretreated with INF-$\gamma$, TNF-$\alpha$ and LPS. The increase of $^{51}Cr$ release with GO(20 mU/ml) was prevented completely by adding 100 ${\mu}M$ SNAP. But the add of SNP, potassium ferrocyanate or potassium ferricyanate did not protect the oxidant injury. Nitrite accumulation was $23{\pm}1.0\;{\mu}M$ from 100 ${\mu}M$ SNAP at 4 hours in phenol red free Hanks' balanced salt solution. But nitrite was not detectable from SNP upto 1 mM The presence of SNAP did not affect the time dependent generation of hydrogen peroxide by GO in phenol red free Hanks' balanced salt solution. Conclusion : Hydrogen peroxide generated by GO causes oxidant injury in RLMVC. Exogenous NO from NO donor prevents oxidant injury, and the protective effect may be related to the ability to release NO. These results suggest that the exogenous NO may be protective on oxidant injury to the endothelium.