• Animal cells and systems
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• 제2권4호
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• pp.521-527
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• 1998

The turnover of epidermal cells after seawater adaptation of the freshwater fishwas studied in the guppy (Poecilia reticulata) by means of Proliferating cell nucleus antigen (PCNA) immunocytochemistry and transmission electron microscopy. The number of PCNA-immunoreactive cells in the epidermis of the seawater-adapted guppies, which becomes thinner than that in the fresh-water, generally increases four times as much. Degeneration of filament-containing cells by necrosis or apoptosis occurs mainly in epidermal cells. Apoptotic filament-containing cells seem to be shed into the water in the environment instead of phagocytosis by adjacent macrophages. The apoptotic chloride cell has a highly condensed cytoplasm and the lumen of tubular system is distended. The apoptotic mucous cell, which has an electron-dense cytoplasm, is characterized by the presence of a large multivesicular body of different electron densities. Macrophages contain many electron-dense lysosomal bodies and large vesicles filled with cellular debris. It is concluded that mitosis and apoptosis of epidermal cells are greatly stimulated when fish are adapting to seawater. This result reflects an increase in epidermal cell turnover by change of environmental salinity.

• 한국토양비료학회지
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• 제36권1호
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• pp.50-56
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• 2003

논에 볏짚과 볏짚퇴비를 시용하고 상시담수와 간단관개로 관리하면서 벼가 심긴 chamber와 벼가 심겨지지 않은 chamber에서 메탄으로 전환되는 정도를 조사하였다. 벼가 심긴 chamber에서는 상시담수에서 메탄 전환율은 시용한 유기물의 신선도에 따라서 증가하였다. 볏짚을 5월에 시용한 처리 (RS5), 볏짚을 2월에 시용한 처리 (RS2), 볏짚퇴비를 5월에 시용한 처리 (RSC)에서 전환율이 각기 14.9%, 9.5%, 4.0%였었다. 범위는 4.0% ~ 14,9 %, 평균은 9.5%였었다. 간단관개에서 전환율도 유사한 경향이었다. 간단관개한 RS5 처리, RS2 처리, RSC 처리에서 메탄으로 전환율을 각기 9.8%, 5.5%, 2.1%였었다. 범위는 2.1% ~ 9.8%, 평균은 5.8%였었다. 벼를 심은 chamber에서 상시담수에서 메탄으로 전환율은 간단관개에서 보다 1.64배 높았다. 벼를 심지 않은 chamber에서 상시담수에서 메탄 전환율은 시용한 유기물의 신선도에 따라서 증가하였다. RS5 처리 RS2 처리 RSC 처리에서 전환율이 각기 8.7%, 3.3%, 3.0%였었다. 범위는 3.0% ~ 8.7%, 평균은 5.0%였었다. 간단관개에서 전환율도 유사한 경향이었다. 간단관개한 RS5 처리, RS2 처리. RSC 처리에서 메탄 전환율을 각기 5.4%, 3.0%, 1.4 %였었다. 범위는 1.4% ~ 5.4%, 평균은 3.3%였었다. 벼를 심은 chamber에서 상시담수에서 메탄 전환율은 간단관개에서 보다 1.52배 높았다.

• Toxicological Research
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• 제14권2호
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• pp.163-169
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• 1998

Fluoride (F), over a narrow concentration range, increases bone formation. Aluminum (Ai) too is biphasic in its action on bone, being mitogenic at very low levels and inhibitory at higher levels. Both F and Al are present in finished drinking water where the chemical interaction of these two agents is well characterized. F and AI, given individually, accumulate preferentially in bone. In addition. in vivo studies have shown that F causes the co-accumulation of Al in bone. Thus, it was necessary to determine the interactive effect of these two agents on bone mitogenesis. Calvaria were obtained from neonatal CD-1 mice and cultured with various concentrations of F (0.05~19 ppm) as NaF, Al (2 ppb~2 ppm) as $AlCl_3$ , or F and Al for 3 days at $37^{\circ}C$ on a rotating roller drum. Alkaline phosphatase activity in calvaria and $\beta$-glucuronidase activity in culture medium were determined as a measures of bone turnover. Alkaline phosphatase activity in calvaria was significantly increased by F (0.05~2 ppm) treatment and $\beta$-glucuronidase activity was slightly increased in the culture medium of calvaria treated with 0.3 ppm Al. The combination of 19 ppm F and 0.3 ppm Al increased alkaline phosphatase activity in calvaria, but did not affect $\beta$-glucuronidase activity, suggesting the interactive effect of fluoride and aluminum on bone turnover.

• The Korean Journal of Ecology
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• 제10권3호
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• pp.139-149
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• 1987

Mathematical models of the litter accumulation, decay and turnover in the grassland and forest ecosystems of equilibrium state of the annual litter production were established to analyse the decay rates of organic and inorganic constituents of the litter. Those models were validated by an application to a Phragmites longivalvis grassland in a delta of the River Nakdong. The decay constants of cold-water-soluble fractions, other carbohydrates, hot-water-soluble fractions, cellulose, crude fat, lignin and crude protein in the litter were 0.730, 0.583, 0.555, 0.505, 0.479, 0.331 and 0.310 respectively. The amount of mineral nutrients such as N. P. K. Ca and Mg returned annually to the soil were estimated to 7.09, 1.34, 2.36, 4.37 and 0.79g/m2 respectively.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.4950-4960
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• 2014

본 연구는 잠수함 승조원들의 이직의도 요인을 분석하기 위해 설문 조사를 통한 실증적 연구를 실시하였으며, 분석도구로 이요인 이론을 토대로 한 Kano모델과 Timko 고객만족계수를 이용하였다. 본 연구는 2013년 11월 1일부터 30일까지 잠수함 승조원 408명을 대상으로 설문조사를 실시하였으며 분석결과 다음과 같은 결과를 도출하였다. 잠수함 승조원들은 잠수함의 열악한 근무환경, 수압에 의한 신체적 위험, 밀폐된 공간에서의 불안감 그리고 불확실한 계급 정년 등이 이직을 생각할 때 가장 많은 영향을 미치는 것으로 분석되었다. 이러한 결과를 바탕으로 분석된 요인에 대해 복지적인 측면과 정책적인 측면에서 요인별로 해소방안을 제시하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권9호
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• pp.1280-1284
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• 2003

The number of protozoa and VFA content in the rumen fluid, in situ disappearance and turnover rate were examined with four rumen-fistulated cattle given either sugarcane stalk or Ruzi grass hay in order to clarify the manner of rumen digestion of sugarcane stalk. Cattle were given either sugarcane stalk or Ruzi grass hay at 1.0% of body weight level with commercial concentrate feed. Feeding sugarcane stalk reduced acetate content and increased propionate and butyrate contents in rumen fluid. While rapidlysoluble fraction of sugarcane stalk was 42%, the insoluble but potentially degradable fraction was only 17%. This clearly showed that sugarcane stalk mainly consisted of water soluble fraction (i.e. sugar) and tough fiber (i.e. bagasse). The ruminal degradation rate of both Ruzi grass hay and sugarcane stalk was lower in the animal given sugarcane stalk in comparison with those given Ruzi grass hay. While the turnover rate of liquid phase was about 50% higher in the animals given sugarcane stalk than in the animals given Ruzi grass hay, that of the solid phase was about 40% lower in the animals given sugarcane stalk. The effective degradability of DM of sugarcane stalk was higher than that of Ruzi grass hay. Sugarcane would be a promising roughage for ruminants in the tropics especially, in the dry season.

• Journal of Chest Surgery
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• 제19권3호
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• pp.479-483
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• 1986

Two patients with funnel chest deformity were corrected at the Department of Thoracic Surgery of Chosun University Hospital. The first case was 5 year old boy, suffering cosmetic deformity, of which hollow cavity was measured 25ml of water. He was corrected by modified Ravitch method. The second case was 12 year old boy, suffering from exertional dyspnea with symmetrical funnel chest deformity, of which hollow cavity was measured 55ml of water. He was corrected by method of sternal turnover. The surgical results of these cases were satisfactory.

• 생태와환경
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• 제38권4호통권114호
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• pp.435-438
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• 2005

We observed the physical, chemical, and biological characteristics of an acidic lake, Lake Katanuma, from 1998 to 2002 at weekly or biweekly intervals, except during the winter. This volcanic lake has a dimictic thermal pattern. In summer, the volcanic heat supply at the lake bottom results in weak thermal stratification. In 1998, 1999, and 2002, short-term holomixis was observed during the stratification period, when the anoxic, hydrogen sulfide-rich water from the hypolimnion spread across the entire lake. In contrast, distinct short-term holomixis did not occur during the stratificatlon period in 2000 and 2001. However, the early onset of the autumn turnover in August 2000 and 2001 caused anoxic conditions to persist throughout the entire water column for more than 2 weeks. The anoxic and hydrogen sulfide-rich conditions affected population densities of chironomid larvae (Chironomus acerbiphilus) and planktonic algae (Chlamydomonas acidophila), both dominant species in Lake Katanuma. Thus, the interannual variations of limnological characteristics influenced the seasonal population changes of these species.

• 환경영향평가
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• 제16권1호
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• pp.69-77
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• 2007

This study has been conducted to assess blackish-water phenomena in Dam reservoir. To searching for the reason, we survey physical changes in reservoir and analyze metal and organic content in particulate materials and water. The blackish-water phenomena in lake A are occurred with turbidity increases in turnover season irregularly. It was reported on 6 Jan. 2005 weakly and the water column mixed with 35~40m depth and water temperature shows $7^{\circ}C$. The turbidity of AD and AM site increased up to 20NTU. Especially, AN site shows 27NTU, such a result makes that Dam manager conclude it to blackish-water phenomena. The results of sequential extraction analysis show that over 80% of Al, Cr and Fe is existed in residual form in sediment. On the other hand, the most part of Mn shows exchangeable and carbonates form, which have a good possibility of release to water column. Mn contents in pore waters of the sediment samples are also found to be ~4 times higher than Fe contents. The metal contents in pore water of different dam sites are in order of AN (Fe: 9.98, Mn: 40.6) > AD(8.33, 37.5) > DD(1.91, 2.55). According to the results of extracted organic materials from sediment, humic substances is occupied with over 85% in total organic carbon including 23~45% of humic acid (HA) and 0.9~8.5% of fulvic acid (FA). However, HA content in pore water is not detectable while FA contents, acid-soluble humic fractions is higher than that of sediment(10~15%). which indicating that FA is a main humic components affecting water color. The color unit per DOC of FA in pore waters of different dam sites are found to be higher in lake A than lake D. From the results, it could be suggested that blackish-water phenomena of lake A are mainly arise from higher concentration of Mn and water soluble organic fractions (e.g., FA) released from sediments as well as the strength of turnover in Dam reservoir.

• 미생물학회지
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• 제31권1호
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• pp.93-98
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• 1993

수계생태계에서 유기물질의 순환을 이해하기 위하여 팔당호에서 종속영양 활성도와 세균세포의 효소활성의 계절절 변화를 연구하였다. 팔당호 I 의 glucose 전환시간은 수층, 퇴적토에서 2-1,300 시간, 17-170 시간, protein hydrolysate 는 5-900 시간, 15-240 시간, acetic acid 는 4-350 시간, 15-230 시간으로 계절적인 변화를 나타냈다. Glucose, protein hydrolysate, acetate 각각의 호흡율은 수층에서 23-32%, 38-41%, 22-28%로 나타났고 퇴적토에서는 34%, 61% and 41% 로 나타났다. 이 결과로 3가지 유기물질 종류 모두가 수층보다 퇴적토에서는 높은 율로 호흡됨을 알 수 있었다. 한편 세균의 $\alpha$-glucosidase, $\beta$-glucosidase, N-acetyl-$\beta$-D-glucosaminidase, aminopeptidase 활성력을 살펴본 결과 수층에서는 효소 각각에 대해 32-44%, 31-32%, 18-34% 61-67% 의 범위를 나타내었고 퇴적토에서는 34%, 40%, 23% 65%로 나타났다.