• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.55-60
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• 1982

This study was carried out in order to clarify the combined effect of cadmium and lead on rat bones when exposed to single metal (1 mg cd/kg body weight) and cambined metals (1 mg cd + 4 mg pb/kg body weight). Seventy five mature rats of Sprague-Dawley species were divided into a control group and a treatment group that were administered by daily peritoneum injection for 7 to 9 weeds, and their body weights were measured every week. The results were summarized as follows 1. Body weight gains of the combined injection group and the single injection groups were lower than that of the control group. 2. In case of the combined injection group, the amount of cadmium accumulated in femur was more than that of the cadmium group. These amounts of cadmium accumulated showed an increasing trend. 3. The lead amount in bone tissue of the combined injection group presented also an increasing trend. In this case, the additive action of cadmium to the lead accumulation in bone tissue was conspicuous. 4. The amounts of calcium and phosphorus in femur showed clear a decreasing trend in the cadmium group and combined administration group. The ratio of calcium and phosphorus (ca/p) in the cadmium group was not different from that of the control group, but in the combined injection group the ratio was a little lower.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1331-1341
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• 2001

Dairy cows are prone to fatty liver during the time of periparturient. Despite of the extensive studies, etiology and solutions for fatty liver are still not well known.The liver synthesizes triglycerides (TG) using precursors from bloodstream and secretes TG in form of very low density lipoprotein (VLDL) into bloodstream for the utilization by peripheral tissues. When the amount of TG synthesis exceeds the amount of secretion in VLDL-TG, TG accumulation within the liver occurs. Hepatic VLDL assembly and secretion involve multi-biochemical events.The availabilities of apolipoprotein B (apoB), E (apoE), microsomal triglyceride transfer protein (MTP) and soluble low density lipoprotein (LDL) receptor are now believed to be some of the main regulators for hepatic VLDL assembly and secretion. Studies in transgenic animals show that overexpression of these proteins stimulates VLDL production and secretion, which provides a possibility for alleviating bovine fatty liver by gene therapy. However, many problems remain to be solved to attain this goal. This review focuses on the molecular mechanisms of hepatic VLDL assembly and secretion, and the possibilities and problems of applying the knowledges to solve bovine fatty liver by gene therapy.

• Journal of the military operations research society of Korea
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• v.24 no.1
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• pp.41-57
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• 1998

Since the aircraft has a property of moving in the three-dimensional space, it may cause personally and financially critical damage in the case of an accident. Among the causes of aircraft accident, human factor has occupied about 70% of all accidents. Specially, fatigue among human's problems has been studied earlier than any other factor. Fatigue has been the cause of 75% of accidents that are related to human factor. So many studies have been conducted. But the direction of these studies mainly attach importance to the sleep loss and circadian rhythm. Limitation for flight time of ICAO is 8 hours per day, civil airlines in domestic line also adopt the limitation. But this rule is not based on human's performance but compromise between labor and management. The long-haul flight brings about a mental block to pilot. This mental block decreases performance of pilot and loses a lot of important information. So this may cause many accidents. This paper is to offer optimal flight time according to the amount of fatigue due to increasing flight time. The optimal flight time is searched through the field experiment. The experiment has adopted two methods. One is to examine pilot's objective fatigue accumulation rate through the critical fusion frequency, and another is to investigate pilot's subjective fatigue feeling through the fatigue subjective symptoms investigation table.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.469-476
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• 2014

The focus of this study was to observe the growth of Chlorella sp., Nannochloris sp., and Botryococcus braunii under mixotrophic conditions (i.e., added glycerol) with the aim of increasing the growth of biomass and algae oil content. A significant growth of biomass was obtained when grown in glycerol rich environment comparing to autotrophic conditions. 5 g/L glycerol yielded the highest biomass concentration for these strains. Mixotrophic conditions improved both the growth of the microalgae and the accumulation of triacylglycerols (TAGs). The maximum amount of TAG in Botryococcus braunii was reached in the growth medium with 10 g/L glycerol and Chlorella sp., Nannochloris sp. with 2 g/L glycerol. The content of saturated fatty acids of Chlorella sp., Nannochloris sp., and Botryococcus braunii was found to be 34.94, 14.23 and 13.39%, and the amount of unsaturated fatty acids was 65.06, 85.78 and 86.61% of total fatty acids, respectively. The fatty acid profiles of the oil for the culture possibility met the necessary requirements and are, therefore, promising resource for biofuel production.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.4
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• pp.351-359
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• 1995

In order to investigate geochemical behaviors of artificial radionuclide($^{137}$ Cs), the fallout deposition of arificial radioisotope($^{137}$ Cs) was measured from May to October in 1994 at the Korea Ocean Research & Development Institute(KORDI), Ansan, Kyunggido, Korea. And to study radioisotopic behavior and cumulative action in soil, soil samples were collected from Kwang-Leung Forest, Kyunggidom and artificial radioisotope ($^{137}$ Cs) and natural radioisotope($^{210}$ Pb) were identified. The amount of $^{137}$ Cs in atmosphere collected by wet deposition process in May was found to be 4.95 to 11.96mBq m$^{-2}$ whereas the amounts of $^{137}$ Cs by dry deposition process in May and October were found to be 4.0mBq g$^{-1}$ and 3.0mBq g$^{-1}$ , respectively. The amount of $^{137}$ Cs accumulated in soil was measured to be 311mBq cm$^{-2}$ , which contained 83% of the total inputs from atmospheric fallout (374 mBq cm$^{-2}$ ) since 1960s. In addition, the accumulation rate and the annual flux of $^{210}$ Pb into soils were 0.32cm yr$^{-1}$ and 34 mBq cm$^{-2}$ yr$^{-1}$ , respectively. Conclusively, it was found that arificial radioisotopes were mainly from the stratosphere and soil resupension of continental China through the troposphere.

• Journal of Powder Materials
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• v.27 no.3
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• pp.193-197
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• 2020

Porous Cu-14 wt% Co with aligned pores is produced by a freeze drying and sintering process. Unidirectional freezing of camphene slurry with CuO-Co₃O₄ powders is conducted, and pores in the frozen specimens are generated by sublimation of the camphene crystals. The dried bodies are hydrogen-reduced at 500℃ and sintered at 800℃ for 1 h. The reduction behavior of the CuO-Co₃O₄ powder mixture is analyzed using a temperature-programmed reduction method in an Ar-10% H₂ atmosphere. The sintered bodies show large and aligned parallel pores in the camphene growth direction. In addition, small pores are distributed around the internal walls of the large pores. The size and fraction of the pores decrease as the amount of solid powder added to the slurry increases. The change in pore characteristics according to the amount of the mixed powder is interpreted to be due to the rearrangement and accumulation behavior of the solid particles in the freezing process of the slurry.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.1
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• pp.161-170
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• 1995

This study is concerned with the numerical analysis of performance on fin-tube heat exchanger under frosting condition. In this work, tube-by-tube method using LMED is employed. The present results are compared with O'Neal's experimental and numerical results. A standard evaporator model with 2rows-2columns is selected to investigate the effects of the various parameters such as fin pitch, air flow velocity, and humidity. The results show that frost thickness and the amount of frost per unit area decrease as fin-pitch becomes narrower. In the meantime, frost thickness and accumulation rate increase with higher inlet air humidity. It is shown that heat transfer rate increases during 30minutes and then it decreases. Heat transfer rate and the amount of frost increase with air velocity, however frost thickness does not increase over a certain velocity.

• The Korean Journal of Ecology
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• v.19 no.3
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• pp.241-249
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• 1996

To determine the accumulation and distribution of heavy metals in plants and soils of roadsides, the leaf and bark of Ginkgo biloba and Platanus occidentalis, and the soil were sample from Masan-city roadside and Chinhae forest land in July and November, 1994. The content of heavy metals from all the samples in Masan-city area was much higher than that in Chinhae forest land. The amount of heavy metals in soil was higher than those in plant parts of boty trees. The total amount of heavy metals of the bark was higher than the leaf of G. biloba plants. But that of the bark was less than the leaf of P. occidentalis. Heavy metal content in plants (leaf, bark) varied among elements and collections. The concentrations of heavey metals in both trees were in the order of Zn > Cu > Pb > Cd. The concentrations of the four heavy metals in leaf and Zn in soil in G. Biloba were seasonally changed. Whereas those in P. occidentalis were not significantly changed. And there was a high correlation between the concentrations of Pb and Cu in both trees.

• Journal of Plant Biology
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• v.25 no.3
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• pp.123-133
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• 1982

The tropic structure and the function of a small pone ecosystem under the tree stand were studied in terms of energy flow. About 28% of total solar radiation was intercepted by the tree canopy over the pond. Primary producers converted 1.1%(3,382 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$) of solar radiation (320,000 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$) into gross primary production. The amount of energy availble to the pond snail was 1,683 kcal.m-2.y-1 of the net production by primary producers and 1,033 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$ of the litter fallen into the pond. The amount of gross secondary production by the pond snail was 245 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$. Judging from these, supply of both net primary production and the litter was indispensable for the maintenance of the pond ecosystem. The total amont of energy as gross primary production plus litter was 4,415 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$(100%). Since the total respiration loss was calculated to be 1,917 kcal$\cdot$$m^{-2}$$\cdot$$y^{-1}$(43.4%), the rate of energy accumulation in the pond estimated to 56.6%.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.1
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• pp.1-10
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• 2001

Since the Industrial Revolution, people have enjoyed an abundant life, owing to the technological innovations of science. However, because of changes in the environment or polution to the environment, it has brought on many chronic diseases. Especially, even though it may be a small amount, if cadmium gets into a human body, because its biological half life is long, it fatally causes a kidney disease and damage to human organisms. It was reported that Metallothioneins(MT), a substance that is closely related with a free radical that comes from environmental pollution and the course of which cadmium, which causes chronic addition in the body, is formed, along with harmful metals, make the toxicity reduce. MT compound led into the body by cadmium indirectly functions as an antioxidation, supplied adequate amount of vitamin E, and suppresses the accumulation of cadmium in heart, liver and blood. Cadmium content found in Korean soil according to the test conducted from 1992 to 1996 was 0.02~0.03mg/kg in cereals, pulses, and potatoes. Free radical scavenger, finding solution for metal substance that comes from environmental pollution from food and natural substances implicates a better future for the study of food science.