• Title/Summary/Keyword: "On-water"

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Fly Ash Application Effects on CH4 and CO2 Emission in an Incubation Experiment with a Paddy Soil (항온 배양 논토양 조건에서 비산재 처리에 따른 CH4와 CO2 방출 특성)

  • Lim, Sang-Sun;Choi, Woo-Jung;Kim, Han-Yong;Jung, Jae-Woon;Yoon, Kwang-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.5
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    • pp.853-860
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    • 2012
  • To estimate potential use of fly ash in reducing $CH_4$ and $CO_2$ emission from soil, $CH_4$ and $CO_2$ fluxes from a paddy soil mixed with fly ash at different rate (w/w; 0, 5, and 10%) in the presence and absence of fertilizer N ($(NH_4)_2SO_4$) addition were investigated in a laboratory incubation for 60 days under changing water regime from wetting to drying via transition. The mean $CH_4$ flux during the entire incubation period ranged from 0.59 to $1.68mg\;CH_4\;m^{-2}day^{-1}$ with a lower rate in the soil treated with N fertilizer due to suppression of $CH_4$ production by $SO_4^{2-}$ that acts as an electron acceptor, leading to decreases in electron availability for methanogen. Fly ash application reduced $CH_4$ flux by 37.5 and 33.0% in soils without and with N addition, respectively, probably due to retardation of $CH_4$ diffusion through soil pores by addition of fine-textured fly ash. In addition, as fly ash has a potential for $CO_2$ removal via carbonation (formation of carbonate precipitates) that decreases $CO_2$ availability that is a substrate for $CO_2$ reduction reaction (one of $CH_4$ generation pathways) is likely to be another mechanisms of $CH_4$ flux reduction by fly ash. Meanwhile, the mean $CO_2$ flux during the entire incubation period was between 0.64 and $0.90g\;CO_2\;m^{-2}day^{-1}$, and that of N treated soil was lower than that without N addition. Because N addition is likely to increase soil respiration, it is not straightforward to explain the results. However, it may be possible that our experiment did not account for the substantial amount of $CO_2$ produced by heterotrophs that were activated by N addition in earlier period than the measurement was initiated. Fly ash application also lowered $CO_2$ flux by up to 20% in the soil mixed with fly ash at 10% through $CO_2$ removal by the carbonation. At the whole picture, fly ash application at 10% decreased global warming potential of emitted $CH_4$ and $CO_2$ by about 20%. Therefore, our results suggest that fly ash application can be a soil management practice to reduce green house gas emission from paddy soils. Further studies under field conditions with rice cultivation are necessary to verify our findings.

Studies on effect and Safety of various Aqua-acupunctures from Scutellariae Radix (다양(多樣)한 황금약침제제(黃芩藥鍼製劑)의 안전성(安定性) 및 효능(效能)에 관한 연구(硏究))

  • Kim, Ho-Kyoung;Ma, Jin-Yeul;Cheon, Won-Kyung;Yun, Su-Young;Kang, Eun-Jung;Joo, Hye-Jeong;Ko, Byoung-Seob
    • Korean Journal of Oriental Medicine
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    • v.3 no.1
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    • pp.183-197
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    • 1997
  • In order to detect the safety and effect of various aqua-acupunctures from Scutellariae Radix, the modifications of boiling, filtration and dilution were employed for the manufacture of aqua-acupunctures. We injected 0.2cc of aqua-acupunctures into Joksamri (足三里) of rat, repeatedly. We compared subacute toxicity of them with saline group, distilled water(D.W.) group, acupuncture group and control group. The results were summarized as follows: 1. The groups were all healthy and alive, and there was no special abnormality in physical condition and autopsy. And there were not any toxic symptoms in repeating application of aqua-acupunctures to the rat, including changes of body weight, organ weight, haematological examination and serum biochemical test. 2. There was slight change of body weight in acupuncture group : We could see significance after 3 days(p<0.05) and after 7 days(p<0.001) in body weight loss. After 9 days, all tested groups were suppressed in body weight increment. 3. Result of organ weight : In Palkang aqua-acupuncture(D-2 group), saline group and acupuncture group there were some statistical significance. Especially, acupuncture group revealed significant result in liver and spleen than aqua-acupunctures. From this result, we could suggest that the efficacy of acupuncture was preceded herbal medicine. 4. In serum biochemical test, we examined glucose(GLU), triglyceride(TG) and cholesterol(CHOL). In comparison with control group, the diluted 10 times of Hwanggum aqua-aqupuncture$({\times}10\;group)$ was recognized significant decrease of glucose, but the diluted 100 times of Hwanggum aqua-acupuncture$({\times}100\;group)$, D-2 group, saline group were confirmed significant increment. There was not any meaningful change of CHOL in all of tested group, excepting the acupuncture group was exhibited statistically significant decrease(p<0.05). In TG level all tested group except complex injection of standard compound(CPA group) and HG, there were significant value iii statistically. The diluted solution was more significant decrease than Hwanggum aqua-acupuncture(HG). The mutual relationship of components of aqua-acupunture tended to decrease level of TG, regardless of its concentration. In acupunture guoup, we gained some interesting result In meaningful decrease in 7G. 5. Haematological examination showed significant increment of granulocytes(GR) in all tested groups except Hwanggum aqua-acupuncture. And the diluted solutions of HG expressed very high increment of them(p<0.001). The GR and Mean Corpuscular Volume(MCV) of acupuncture group showed statistical significance.

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A Study on Improvement for Fishing Gear and Method of Pound Net - I - Net Shapes of the Commerical Net in the Flow - (정치망 어구어법의 개발에 관한 연구-I - 현용어구의 흐름에 대한 형상 변화 -)

  • Yun, Il-Bu;Lee, Ju-Hee;Kwon, Byeong-Guk;Cho, Young-Bok;Yoo, Jae-Bum;Kim, Seong-Hun;Kim, Boo-Young
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.4
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    • pp.268-281
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    • 2004
  • A study was carried out in order to estimate the deformation of the pound net according to the current by the model test in the circulating water channel. The tension of the frame rope and the variation of net shape were measured to investigate the deforming of the model pound net in the flow. The results are obtained as follows; 1. The experimental equation between tensions (R) of the frame rope and velocity (ν)was found to be R=$19.58v^{1.98}$($r^2$=0.98) in case of the upperward flow with fish court net and R=$26.90v^{1.72}$($r^2$=0.95)at the upperward flow with bag net according to the velocity from 0.0m/s to 0.6m/s, respectively. 2. As the variation of flow speed inside of the model net was gradually decreased according as which is passed through netting panels, in case of the upperward flow with fish court net, the flow speed was about 70% of initial flow speed at 0.1m/s, 60% at 0.2m/s, 50% at 0.3m/s and 40% 0.4~0.6m/s at the measurement point(h) inside of the first bag net, respectively. In case of the upperward flow with bag net, as the flow speed was steeply decreased according as which if passed through the second bag net, it was 30~60% of the initial flow speed and was 20~30% inside of the first bag net and was about 10~20% inside of the inclined passage net. 3. In case of the upperward flow with fish court net, the variation of deformed angle of fish court net was from 0$^{\circ}$ to 70$^{\circ}$and that of inclined passage net was from 0$^{\circ}$ to 63$^{\circ}$and that of the second bag net was from 0$^{\circ}$ to 47$^{\circ}$ . 4. In case of the upperward flow with fish court net, the variation of deformed angle of the second bag net was changed from 0$^{\circ}$ to 70$^{\circ}$and that of the inclined passage net was from 0$^{\circ}$ to 55$^{\circ}$ and that of the fish court net was from 0$^{\circ}$ to 50$^{\circ}$. The depth ratio of the first bag net was changed from 0% to 35% and that of the second bag net was from 0% to 20% and that of the inclined passage net was from 0% to 35%. In the flow speed 0.5m/s, the inclined passage net was raised up to the entry of the bag net and then prevented it more over 90%. 5. To be increased the opening volume of pound net, it needs to attach the added weight outside of the fish court net, inclined passage net and bag net. At the same time, it needs to adjust the tension of the twine for maintenance of the shape.

Wind and Flooding Damages of Rice Plants in Korea (한국의 도작과 풍수해)

  • 강양순
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.s02
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    • pp.45-65
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    • 1989
  • The Korean peninsular having the complexity of the photography and variability of climate is located within passing area of a lots of typhoon occurring from the southern islands of Philippines. So, there are various patterns of wind and flooding damages in paddy field occuring by the strong wind and the heavy rain concentrated during the summer season of rice growing period in Korea. The wind damages to rice plants in Korea were mainly caused by saline wind, dry wind and strong wind when typhoon occurred. The saline wind damage having symptom of white head or dried leaves occurred by 1.1 to 17.2 mg of salt per dry weight stuck on the plant which was located at 2. 5km away from seashore of southern coastal area during the period(from 27th to 29th, August, 1986) of typhoon &Vera& accompanying 62-96% of relative humidity, more than 6 m per second of wind velocity and 22.5 to 26.4$^{\circ}C$ of air temperature without rain. Most of the typhoons accompanying 4.0 to 8. 5m per second of wind and low humidity (lesp an 60%) with high temperature in the east coastal area and southen area of Korea. were changed to dry and hot wind by the foehn phenomenon. The dry wind damages with the symptom of the white head or the discolored brownish grain occurred at the rice heading stage. The strong wind caused the severe damages such as the broken leaves, cut-leaves and dried leaves before heading stage, lodging and shattering of grain at ripening stage mechanically during typhoon. To reduce the wind damages to rice plant, cultivation of resistant varieties to wind damages such as Sangpoongbyeo and Cheongcheongbyeo and the escape of heading stage during period of typhoon by accelerating of heading within 15th, August are effective. Though the flood disasters to rice plant such as earring away of field, burying of field, submerging and lodging damage are getting low by the construction of dam for multiple purpose and river bank, they are occasionally occurred by the regional heavy rain and water filled out in bank around the river. Paddy field were submerged for 2 to 4 days when typhoon and heavy rain occurred about the end of August. At this time, the rice plants that was in younger growing stage in the late transplanting field of southern area of Korea had the severe damages. Although panicles of rice plant which was in the meiotic growing stage and heading stage were died when flooded, they had 66% of yield compensating ability by the upper tilling panicle produced from tiller with dead panicle in ordinary transplanting paddy field. It is effective for reduction of flooding damages to cultivate the resistant variety to flooding having the resistance to bacterial leaf blight, lodging and small brown planthopper simultaneously. Especially, Tongil type rice varieties are relatively resistant to flooding, compared to Japonica rice varieties. Tongil type rice varieties had high survivals, low elongation ability of leaf sheath and blade, high recovering ability by the high root activity and photosynthesis and high yield compensating ability by the upper tillering panicle when flooded. To minimize the flooding and wind damage to rice plants in future, following research have to be carried out; 1. Data analysis by telemetering and computerization of climate, actual conditions and growing diagnosis of crops damaged by disasters. 2. Development of tolerant varieties to poor natural conditions related to flooding and wind damages. 3. Improvement of the reasonable cropping system by introduction of other crops compensating the loss of the damaged rice. 4. Increament of utilization of rice plant which was damaged.

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Studies on Lipids in Fresh-Water Fishes 8. Comparison of Lipid Components among Wild and Cultured Carp (Cyprinus carpio) and Israeli Carp (Cyprinus carpio nudus) (담수어의 지질에 관한 연구 8. 천연 및 양식 잉어와 이스라엘 잉어의 지질성분 비교)

  • CHOI Jin-Ho;RHIM Chae-Hwan;BAE Tae-Jin;YOON Tai-Heon;LEE Kang-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.5
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    • pp.447-454
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    • 1985
  • As a part of serial study for comparing lipid components in freshwater fishes, this work was undertaken to compare the lipid components among wild and cultured carp, Cyprinus carpio, and Israeli carp, Cyprinus carpio nudus. The lipid components of cultured carp were analyzed and compared with those of wild and Israeli carp. In the content of total lipid, the lipid content in cultured carp was slightly lower than that in wild one, but similar to that in Israeli carp. The lipid contents in viscera of wild and cultured carp were 2 times higher than those in edible portion, but the lipid content in viscera of Israeli carp showed a similar trend to that in edible portion. In the fatty acid composition of neutral lipid in edible portion, percentages of $C_{18:1},\;C_{18:2},\;C_{18:3},\;C_{22:5}\;and\;C_{22:6}$ in cultured carp wire higher than those in wild one, while percentages of $C_{16:0},\;C_{18:0},\;C_{16:1},\;C_{20:4}\;and\;C_{20:5}$ lower, and percentage of $C_{18:2}$ in Israeli carp was noticeably higher than that in wild and cultured carp. In the case of phospholipid in edible portion, percentages of $C_{18:0},\;C_{18:1},\;C_{18:2},\;C_{18:3}\;and\;_C{22:6}$ in cultured carp were higher than those in wild one, while percentages of $C_{16:0},\;C_{16:1},\;C_{20:4},\;C_{20:5}\;and\;C_{22:5}$ lower. The unsaturation (TUFA/TSFA) of neutral lipid in cultured carp was slightly higher than that in wild one, but slightly lower than that in Israeli carp. In the case of phospholipid, the unsaturation showed a similar trend to that of neutral lipid. The essential fatty acid content(TEFA) of neutral lipid in edible portion of cultured carp was higher than that of wild one, but that in viscera lower. In the case of phospholipid in edible portion, the essential fatty acid content in Israeli carp was slightly higher than that in wild and cultured carp, and that in wild one was higher than that in cultured one. The w3 highly unsaturated fatty acid contents(w3 HUFA) of neutral lipid almost showed a similar trend to the essential fatty acid contents in wild and cultured carp, and Israeli carp. In the case of phospholipid, the w3 HUFA in Israeli carp was considerably higher than those in cultured and wild carp. In the ratio (A/C) of fatty acid content(A) in cultured carp to that(C) in diet, the A/C ratios of $C_{20:5}\;w3(0.12),\;C_{22:5}\;w6(0.53),\;C_{22:5}\;w3(0.68)\;and\;C_{22:6}\;w3(0.26)$ were much lower and in the ratio (B/C) of fatty acid content (B) in Israeli carp, the B/C ratios of $C_{18:3}\;w3(0.61),\;C_{20:5}\;w3(0.11),\;C_{22:4}\;w6(0.16),\;C_{22:5}\;w6(0.07)\;and\;C_{22:6}\;w3(0.79)$ were also lower than the other fatty acid. Consequently, it is considered that the ratios of w3 HUFA is related to the biosynthesis of polyenoic acid and growth rates of cultured and Israeli carp.

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Studies on Lipids in Fresh-Water Fishes 7. Comparison of Lipid Components among Wild and Cultured Eel (Anguilla japonica), and Conger Eel (Astroconger myriaster) (담수어의 지질에 관한 연구 7. 천연 및 양식 뱀장어와 붕장어의 지질성분 비교)

  • CHOI Jin-Ho;RHIM Chae-Hwan;BAE Tae-Jin;BYUN Dae-Seok;YOON Tai-Heon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.5
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    • pp.439-446
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    • 1985
  • This study was designed to compare the lipid components among wild and cultured eel, Anguilla japonica, and conger eel, Astroconger myriaster. The lipid components of cultured eel were analyzed and compared with those of wild and conger eel. In the content of total lipid, the lipid content in cultured eel was slightly higher than that in wild one, but 2 times higher than that in conger eel. The lipid contents in edible portion of wild and cultured eel were 5 times higher than those in viscera, but the lipid content in edible portion of conger eel showed a similar trend to that in viscera. In the fatty acid composition of neutral lipid in edible portion, percentages of $C_{14:0},\;C_{16:0}\;and\;C_{18:1}$ in cultured eel were higher than those in wild one, while percentages of $C_{16:1},\;C_{18:2},\;C_{18:3},\;C_{20:4},\;C_{20:5},\;C_{22:5}\;and\;C_{22:6}$ lower, and percentages of $C_{18:0},\;C_{20:4}\;and\;C_{22:6}$ in conger eel were noticeably higher than those in wild and cultured eels. In the case of phospholipid in edible portion, percentages of $C_{18:0}\;and\;C_{18:2}$ in cultured eel were higher than those in wild one, while percentages of $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{18:3},\;C_{20:4},\;C_{20:5},\;C_{22:5}\;and\;C_{22:6}$ lower. The unsaturation (TUFA/TSFA) of neutral lipid was no significant difference among wild and cultured eel, and conger eel, but that of phospholipid in wild eel was higher than that in cultured eel and conger eel. The essential fatty acid content(TEFA) of neutral lipid in edible portion of wild eel was 3 times higher than that of cultured one. but the TEFA of phospholipid in edible portion was no significant difference among wild and cultured eels, and conger eel. The w3 highly unsaturated fatty acid content (w3 HUFA) of neutral lipid in edible portion of wild eel was 2.0 to 2.5 times higher than that of cultured eel and conger eel, but the w3 HUFA of phospholipid in edible portion of wild eel was noticeably higher than that of cultured eel and conger eel. In the ratio (A/B) of fatty acid content (A) in cultured eel to that (B) in diet, the A/B ratios of $C_{18:2}\;w6,\;C_{18:3}\;w3,\;C_{20:5}\;w3\;and\;C_{22:6}\;w3$ were 0.23 to 0.48 much lower than the other fatty acid. Consequently, it is considered that the ratios of w3 HUFA is related to the biosynthesis of polyenoic acid and growth rate of cultured eel.

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Relationships between Micronutrient Contents in Soils and Crops of Plastic Film House (시설재배 토양과 작물 잎 중의 미량원소 함량 관계)

  • Chung, Jong-Bae;Kim, Bok-Jin;Ryu, Kwan-Sig;Lee, Seung-Ho;Shin, Hyun-Jin;Hwang, Tae-Kyung;Choi, Hee-Youl;Lee, Yong-Woo;Lee, Yoon-Jeong;Kim, Jong-Jib
    • Korean Journal of Environmental Agriculture
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    • v.25 no.3
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    • pp.217-227
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    • 2006
  • Micronutrient status in soils and crops of plastic film house and their relationship were investigated. Total 203 plastic film houses were selected (red pepper, 66; cucumber, 63; tomato, 74) in Yeongnam region and soil and leaf samples were collected. Hot-water extractable B and 0.1 N HCl extractable Cu, Zn, Fe, and Mn in soil samples and total micronutrients in leaf samples were analyzed. Contents Zn, Fe, and Mn in most of the investigated soils were higher than the upper limits of optimum level for general crop cultivation. Contents of Cu in most soils of cucumber and tomato cultivation were higher than the upper limit of optimum level, but Cu contents in about 30% of red pepper cultivation soils were below the sufficient level. Contents of B in most soils of cucumber and tomato were above the sufficient level but in 48% of red pepper cultivation soils B were found to be deficient. Micronutrient contents in leaf of investigated crops were much variable. Contents of B, Fe, and Mn were mostly within the sufficient levels, while in 71% of red pepper samples Cu was under deficient level and in 44% of cucumber samples Cu contents were higher than the upper limit of sufficient level. Contents of Zn in red pepper and cucumber samples were mostly within the sufficient level but in 62% of tomato samples Zn contents were under deficient condition. However, any visible deficiency or toxicity symptoms of micronutrients were not found in the crops. No consistent relationships were found between micronutrient contents in soil and leaf, and this indicates that growth and absorption activity of root and interactions among the nutrients in soil might be important factors in overall micronutrient uptake of crops. For best management of micronutrients in plastic film house, much attention should be focused on the management of soil and plant characteristics which control the micronutrient uptake of crops.

Studies on the Organo-mercury Residues in Rice Grain -I. Mercury residues in rice seeds treated with organo-mercury fungicide- (수도(水稻)에 처리(處理)된 유기수은제(有機水銀劑)의 잔류성(殘留性)에 관(關)한 연구(硏究) -제1보(第1報) 침지용유기수은제(浸漬用有機水銀劑)로 처리(處理)된 수도종자중(水稻種子中)의 수은잔류량(水銀殘留量)에 관(關)하여-)

  • Lee, Dong-Suk
    • Applied Biological Chemistry
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    • v.8
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    • pp.87-93
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    • 1967
  • 1) For the micro-analysis of mercury in plant materials, the method of Furutani was shown to be the simplest and most efficient way and the recovery of the assay was about 98%. 2) When the rice grain was soaked in 1/1000 diluted solution of organo-mercury fungicide for 8 hours at the end of March, the amounts of mercury residues in the brown rice and unhulled rice were 8.8 to $9.5\;{\mu}g/g$ seeds and 10.1 to $10.7\;{\mu}g/g$ seeds, respectively. 3) By washing the treated rice seeds with running water for three days, tile residual mercury concentration was reduced to 1/4 to 1/5; thus the mercury residues were 1.86 to $1.92\;{\mu}g/g$ for brown rice and 1.96 to $2.93\;{\mu}g/g$ for unhulled rice. 4) The residual mercury was present more in the unhulled rice than in the brown rice, either before or after washing of the treated seeds. 5) Among the different rice varieties, no difference was observed in mercury residues by seed treatment and washing.

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The Role of c-Jun N-terminal Kinase in the Radiation-Induced Lung Fibrosis (방사선에 의한 폐 섬유화증에서 c-Jun N-terminal Kinase(JNK)의 역할)

  • Uh, Soo-Taek;Hong, Ki-Young;Lee, Young-Mok;Kim, Ki-Up;Kim, Do-Jin;Moon, Seung-Hyuk;Kim, Yong-Hoon;Park, Choon-Sik;Yeom, Uk;Kim, Eun-Suk;Choi, Doo-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.50 no.4
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    • pp.450-461
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    • 2001
  • Background : The underlying pathogenesis of radiation-induced lung fibrosis (RTLF) has not been very well defined. However, the role of TGF-$\beta$ in the generation of RTLF has been a major focus because there is an increase in the expression of both the TGF-${\beta}m$-RNA and its protein preceding RTLF lesions. The down stream signal after a TGF-$\beta$ stimulated lung fibrosis includes the activation of many mediators such as Smad and c-Jun N-terminal kinase (JNK) through TAK1. It is we hypothesized that JNK activation may play a pivotal role in RTLF pathogenesis through increased transcription of the fibrogenic cytokines. The present study evaluates JNK activity in alveolar macrophages after irradiation and the relationship between JNK activity and the amount of collagen in the lung tissues. Methods : C57BL/6 mice(20-25 gr, males) received chlorotetracycline(2g/L) in their drinking water 1 week prior to irradiation and continuously there after. The mice were irradiated once with 1400 cGy of $60CO{\gamma}$-ray over the whole chest. The cellular composition of the whole lung bronchoalveoalr lavage fluids(BALF), elastin expression in the lung tissues, the level of hydroxyproline in lung tissues, and an in vitro JNK assay was measured before irradiation and one, four, and eight weeks after irradiation (RT). Results : The volumes of BALF retrieved from instilled 4 mL of saline with 2% heparin were 3.7-3.8 mL for each group. The cell numbers were similar before($4.1{\times}10^4{\pm}0.5{\times}10^4/mL$) and 1 week($3.1{\times}10^4{\pm}0.5{\times}10^4/mL$) after RT. At four and eight weeks after RT, the cell number reached to $14.0{\times}10^4{\pm}1.5{\times}10^4mL$ and $10.0{\times}10^4{\pm}1.3{\times}10^4/mL$, respectively. There we no changes in the lymphocytes and neutrophils population observed in the BALF after RT. The H-E stain of the lung tissues did not show any structural and fibrotic change in the lung tissues at 4 and 8 weeks after RT. In addition, the amount of elastin and collagen were not different on Verhoeff staining of the lung tissues before RT to eight weeks after RT. The hydroxyproine content was measured with the left lung dissected from the left main bronchus. The lung were homogenized and hydrolyzed with 6 N Hel for 12 hours at $110^{\circ}C$ then measured as previously described. The content of hydroxyproline, standardized with a lung protein concentration, reached a peak 4 weeks after RT, and thereafter showed a plateau. AnIn vitro JNK assay using c-$Jun_{1-79}$-GST sepharose beads were performed with the alveolar macrophages obtained from the BAL. JNK activity was not detected prior to RT, However, the JNK activity increased from one week after RT and reached a peak four weeks after RT. Conclusion : JNK may be involved in the pathogenesis because the JNK activity showed similar pattern observed with the hydroxyproine content. However, it is necessary to clarify that the JNK increases the transcription of fibrogenic cyiokines through the transcription factor.

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Comparison of Naphthalene Degradation Efficiency and OH Radical Production by the Change of Frequency and Reaction Conditions of Ultrasound (초음파 주파수 및 반응조건 변화에 따른 나프탈렌 분해효율과 OH 라디칼의 발생량 비교)

  • Park, Jong-Sung;Park, So-Young;Oh, Je-Ill;Jeong, Sang-Jo;Lee, Min-Ju;Her, Nam-Guk
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.2
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    • pp.79-89
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    • 2009
  • Naphthalene is a volatile, hydrophobic, and possibly carcinogenic compound that is known to have a severe detrimental effect to aquatic ecosystem. Our research examined the effects of various operating conditions (temperature, pH, initial concentration, and frequency and type of ultrasound) on the sonochemical degradation of naphthalene and OH radical production. The MDL (Method detection limit) determined by LC/FLD (1200 series, Agilient) using C-18 reversed column is measured up to 0.01 ppm. Naphthalene vapor produced from ultrasound irradiation was detected under 0.05 ppm. Comparison of naphthalene sonodegradion efficiency tested under open and closed reactor cover fell within less than 1% of difference. Increasing the reaction temperature from $15^{\circ}C$ to $40^{\circ}C$ resulted in reduction of naphthalene degradation efficiency ($15^{\circ}C$: 95% ${\rightarrow}$ $40^{\circ}C$: 85%), and altering pH from 12 to 3 increased the effect (pH 12: 84% ${\rightarrow}$pH 3: 95.6%). Pseudo first-order constants ($k_1$) of sonodegradation of naphthalene decreased as initial concentration of naphthalene increased (2.5 ppm: $27.3{\times}10^{-3}\;min^{-3}\;{\rightarrow}$ 10 ppm : $19.3{\times}10^{-3}\;min^{-3}$). Degradation efficiency of 2.5 ppm of naphthalene subjected to 28 kHz of ultrasonic irradiation was found to be 1.46 times as much as when exposed under 132 kHz (132 kHz: 56%, 28 kHz: 82.7%). Additionally, its $k_1$ constant was increased by 2.3 times (132 kHz: $2.4{\times}10^{-3}\;min^{-1}$, 28 kHz: $5.0{\times}10^{-3}\;min^{-1}$). $H_2O_2$ concentration measured 10 minutes after the exposure to 132 kHz of ultrasound, when compared with the measurement under frequency of 28 kHz, was 7.2 times as much. The concentration measured after 90 minutes, however, showed the difference of only 10%. (concentration of $H_2O_2$ under 28 kHz being 1.1 times greater than that under 132 kHz.) The $H_2O_2$ concentration resulting from 2.5 ppm naphthalene after 90 minutes of sonication at 24 kHz and 132 kHz were lower by 0.05 and 0.1 ppm, respectively, than the concentration measured from the irradiated M.Q. water (no naphthalene added.) Degradation efficiency of horn type (24 kHz) and bath type (28 kHz) ultrasound was found to be 87% and 82.7%, respectively, and $k_1$ was calculated into $22.8{\times}10^{-3}\;min^{-1}$ and $18.7{\times}10^{-3}\;min^{-1}$ respectively. Using the multi- frequency and mixed type of ultrasound system (28 kHz bath type + 24 kHz horn type) simultaneously resulted in combined efficiency of 88.1%, while $H_2O_2$ concentration increased 3.5 times (28 kHz + 24 kHz: 2.37 ppm, 24 kHz: 0.7 ppm.) Therefore, the multi-frequency and mixed type of ultrasound system procedure might be most effectively used for removing the substances that are easily oxidized by the OH radical.