• Journal of Veterinary Clinics
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• v.11 no.1
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• pp.485-505
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• 1994

Lead toxicity was evaluated in forty-five cats on a balanced diet, treated with 0(control), 10, 100(low), 1, 000, 2, 000 and 4, 000(high)ppm of lead acetate orally on a body weight basis. The objectives were to describe the gross and histopathologic changes and to demonstrate what tissue lead concentrations correlate with the known dosages of lead. In subclinical lead toxicity, greater than 80% of the absorbed lead was deposited in the bone, whereas in more acute lead toxicity, 42% of absorbed lead was deposited in the bone and 36% and 20% of absorbed lead was deposited in the kidneys and in the liver, respectively. No gross lesions were found in the nervous system. Yellow-brown colored livers appear to be associated with lead toxicity. Neuronal necrosis in the cerebrum was the most predominant histopathologic finding. Astrocytic proliferation in the cerebral gray matter was observed in 1 high dose cat. Gliosis was noted in the cerebral cortex of 6 high dose cats. Two high dose cats had demyelination in the deepest layer of the cortical gray matter of the cerebrum. Extravasation of red cells and cavitation around the vessels were found in the cerebrum of 1 high dose cat. Six high dose cats had degeneration of Purkinje cells in the cerebellum. The microscopic findings in the peripheral nerves were ambiguous. In more acute toxicity, the cats had lead inclusions in the epithelial cells of proximal tubules of the kidneys of 7 cats and hepatocytes of the liver of S cats. These inclusions could be seen wlth H&E, but were more prominent with orcein staining. Two high dose cats had granulomas and connective tissue hyperplasia between tubules of the kidneys. Periportal hepatocyte vacuolization was observed in the liver of 22 cats. Vacuolization of seminiferous tubules and a reduced number of spermatogonia(indicative of reduced spermatogenesis) were found in the testis of 5 treated cats. Cystic ovaries were observed in 3 high dose cats and poor development of oogonia was found in 2 cats. The diagnosis of lead toxicity in cats can be suspected on the basis of the histopathologic lesions described, and can be of value in contributing to a diagnosis. A reliable diagnosis of lead poisoning can be helped utilizing tissue lead analysis(post molten)

• Journal of Environmental Policy
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• v.7 no.3
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• pp.89-120
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• 2008

With petroleum being a major source of energy in Korea, the quantity of petroleum transported via ocean routes is on its way up due to increased consumption. Due to the increase, more than 300 cases of pollution caused by petroleum occur annually. Moreover, the number of oil-spill accidents is also on the rise. Causes of such accidents, not including the disposal of waste oil on purpose, turn out to be human error during navigation or defects in the vessels, showing that most accidents are caused by humans. Therefore, to prevent future oil spills, it is imperative that navigation efficiency be enhanced by improving the quality of navigators and replacing old vessels with newer ones. Nevertheless, such improvements cannot occur overnight, so long- and mid-term efforts should be made to achieve it institutionally. As large-scale oil-spill accidents can happen at anytime along the coastal waters of Korea, it is necessary to set-up institutional devices which go beyond the compensation limit of 92FC. The current special law regarding this issue has its limits in that it prescribes compensation be supplemented solely by national taxes. Therefore, the setting-up of a new 'national fund' is recommended for consideration rather than to subscribe to the '2003 Convention for the Supplementary Fund'. It is strongly suggested that a National fund be created from fees collected from oil companies based on the risks involved in oil transportation and according to the profiteers pay principle. In addition, a public fund should be created to handle general environmental damage, such as the large-scale destruction of the ecosystem, which is distinct from the economic damage that harms the local people. The posterior responses to the large-scale oil spill have always been unsatisfactory because of the symbolic nature of the disasters included in such accidents. Oil-spills can be prevented in advance, because they are caused by human beings. But once they occur, they inflict long-term damage to both human life and the natural ecosystem. Therefore, the best response to future oil-spills is to work to prevent them.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.56-64
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• 2001

Composting of livestock feces is economic and safe process to decrease the possibility of direct leakage of organic pollutants to ecosystem from commercial and environmental point of view. This study was conducted with three different experiments related to composting of livestock feces. The purpose of experiment 1 was to investigate changes of characteristic of compost pile during composting period by low temperature in cold season. To compare composting effect of experimental compost pile and control pile exposed in cold air, experimental compost piles were warmed up by hot air until their temperatures were reached at $35^{\circ}C$. Sawdust, Ricehull and Ricestraw were mixed with livestock feces as bulking agent. The highest temperatures of compost pile during composting period were in sawdust, rice hull, rice straw, and control were $75^{\circ}C$, $76^{\circ}C$, $68^{\circ}C$, $45^{\circ}C$ respectively. Moisture content, pH, C/N and volume of compost were decreased during composting period. Experiment 2 was carried out to study utilization effect of compost by plant. A corn was cultivated for 3 years on fertilized land with compost and chemical fertilizer. The amount of harvest and nutrition value of corn were analyzed. In first year of trial, the amount of harvest of corn on land treated with compost was lower by 20% than that of land treated with chemical fertilizer. In second year, there was no difference in yield of com between compost and chemical fertilizer. In third year, the yield of com on land fertilized with compost was much more than that of land fertilized with chemical fertilizer. The purpose of experiment 3 was to estimate the decrease of malodorous gas originating from livestock feces by bio-filter. Four types of bio-filters filled with saw dust, night soil, fermented compost and leaf mold were manufactured and tested. Each bio-filter achieved 87-95% $NH_3$ removal efficiency. This performance was maintained for 10 days. The highest $NH_3$ removal efficiency was achieved by leaf mold on the first day of operation period. It reduced the concentration of $NH_3$ by about 95%. Night soil and fermented compost showed nearly equal performance of 93 to 94% for 10 days from the beginning of operation. The concentration of hydrogen sulfide and methyl mercaptan originating for compost were equal to or less than $3mg/{\ell}$ and $2mg/{\ell}$, respectively. After passing throughout the bio-filter, hydrogen sulfide and methyl mercaptan were not detected.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.315-321
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• 2012

Fate of acetamiprid and imidacloprid aerially sprayed to control pine wood nematode (Bursaphelenchus xylophilus) were studied in a forest of Haman area. Acetamiprid 20% SL or imidacloprid 20% DC were diluted 100 times and applied two times as rate of 50 L/ha using an aircraft of Bell 206 L helicopter. Average acetamiprid deposits on forest floor ranged from 2 to 4% of standard aerial application rate. Following to the second application, acetamiprid deposits in the pine needle ranged 1.8~8.5 mg/kg and then gradually decreased to 1.2~2.1 mg/kg after 48 days. Deposits on the plant washed off by rainfall and reached to soil surface was ca. 17% of the application rate. All of acetamiprid on the ground resided in the forest floor covering the soil surface, where acetamiprid residues were decreased to a quarter at 48 days after the second application, but they were not detected in soil beneath it. And the only low level of acetamiprid residues, 0.0003 mg/L, was detected in the reservoir nearby the experimental forest on the day of aerial application. The acetamiprid detection was presumably due to spray drift. And average imidacloprid deposits on forest floor ranged from 1 to 3% of standard aerial application rate. Following to the second application, imidacloprid deposits in the pine needle analysed very low concentration of 0.1 mg/kg, but the amount of imidacloprid in wash-off in standard and two-fold treatment were ca. 8% and 4% of the application rate, respectively. Most of imidacloprid on the ground also resided in the forest floor, where imidacloprid residues were decreased to a twentieth at 111 days after the second application, and they were detected below 0.5% of the application rate in sol beneath it. And the low level of imidacloprid, 0.0003~0.0017 mg/L, were detected in the streams in the experimental forest. It was not to the level of contamination concerns.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.123-133
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• 2007

This study analyzed whether a transit network with hierarchy is efficient or not, and if transit network hierarchy has cost efficiency, then which condition guarantees the efficiency of the transit network hierarchy. The authors modeled the total cost of the transit network and suggested the conditions in which the transit network hierarchy has cost efficiency through comparing the cost of the transit network with and without hierarchy. The efficiency of transit network hierarchy is guaranteed when the travel cost savings induced by using a higher hierarchy transit network is larger than the increasing non-travel cost, which is the sum of access cost, waiting cost, and operating cost, induced by the introduction of a higher hierarchy transit network. This result is consistent with common sense and with the concept of cost and benefit analysis. If a passenger traveling within the area divided by a higher hierarchy transit network uses only a lower hierarchy transit network and the passenger traveling out of the area divided by the higher hierarchy transit network uses both lower and higher hierarchy transit networks, the travel demand using the higher hierarchy transit network is inversely proportional to the square of the line spacing. This means that the transit network becomes more efficient and small increases of travel demand guarantee the efficiency of the transit network hierarchy as the connectivity of the network becomes higher. This result shows that transit networks have economies of aggregation. This study is the first analytical research on transit network hierarchy and is expected to be a basis for numerical research. However, numerical research should complement this study, since analytical research has some limitations for considering a real network.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.91-98
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• 2016

The growth area of living modified (LM) cotton has steadily increased every year, since its first commercialization in 1996. Development of environmental risk assessment tools and techniques for LM cotton is required for ecosystem safety. We therefore developed multiplex PCR assays for simultaneous detection of two (MON15985, MON531) and four (GHB614, LLCOTTON25, MON88913 and MON1445) LM cotton events approved in Korea, with event specific primer pairs. The PCR reactions were optimized by using event specific primers of six LM cottons at various concentrations. The reactions allows amplification of estimated amplicons of MON15985 (214 bp), MON531 (270 bp), GHB614 (119 bp), LLCOTTON25 (164 bp), MON88913 (276 bp), and MON1445 (389 bp) from multiplex PCR reactions. The multiplex PCR assay developed allowed that two annealing steps (15 cycles at $55^{\circ}C$ and 25 cycles at $60^{\circ}C$) were performed for amplification of distinguished two LM cottons, and only one annealing step (50 cycles at $60^{\circ}C$) was necessary for tetraplex PCR. Primer extension step of all PCR reactions was skipped for time-effective amplification. Our methods suggest that two multiplex PCR assays can be cost-effective and a rapid diagnostic tool for environmental LMO monitoring of six LM cottons.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.472-487
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• 2020

With the emergence of abnormal climate due to the rapid industrialization, the importance of water quality management and management costs are increasing every year. In Korea, for the management of total phosphorus and total nitrogen, the major materials causing the water quality pollution, coagulants are injected in sewage treatment plants to process organic compounds. However, if the coagulant is injected in an excessive amount to PAC (Poly Aluminium Chloride), a secondary pollution problem might occur. As such, a study on the applicability of natural material-based coagulant is being conducted in Korea. Thus, this study aimed to evaluate the applicability of a mixed coagulant developed by analyzing water quality pollutants T-P, T-N as well as their turbidity, in order to derive the optimum mixing ratio between PAC and torrefied wood flour for the primary settling pond effluent. Under the condition where the content of PAC (10%) and torrefied wood flour is 1%, T-P showed the maximum removal efficiency of 92%, and T-N showed approximately 22%. This indicates that removal of T-N which includes numerous positively charged organic compounds that are equivalent to mixed coagulant is not well accomplished. Turbidity showed the removal efficiency of approximately 91%. As such, 1% of torrefied wood flour was determined to be the optimum addition. As a result of analyzing the removal efficiency for organic compounds by reducing PAC concentration to 7%, T-P showed a high maximum removal efficiency of 91%, T-N showed 32%, and turbidity showed the maximum of 90%. In addition, a coagulation process is performed by using the mixed coagulant based on 1% content of torrefied wood flour produced in this study by performing a coagulation performance comparative experiment with PAC (10%). As a result, PAC concentration was reduced to 30-50%, a similar performance with other coagulants in market was secured, PAC injection amount was reduced that an economic effect can be achieved, and it is considered to perform a stable water treatment that reduces the secondary pollution problem.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.112-117
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• 1993

Background Radioiodine ($^{131}I$), a major component of nuclear fallout and a valuable therapeutic agent for thyrotoxicosis and thyroid cancer, has been regarded as a mutagen or a carcinogen without any convincing evidence. To evaluate the genotoxicity of radioiodine ($^{131}I$) we performed a micronuclei test in mice bone marrow. Materials and methods : Mice (ICR strain, $25{\sim}30 g$) were divided to 4 groups: control, group 1 (0.17 mCi/kg, usual therapeutic dose for thyrotoxicosis), group 2 (1.67 mCi/kg, usual therapeutic dose for thyroid cancer), and group 3 (16.67 mCi/kg, usual accumulated dose causing bone marrow suppression). $^{131}I$ was administered intraperitoneally. Ten mice of each group were sacrificed at days 1 and 3. Bone marrow were smeared and stained with May-Grunwald Giemsa method. One thou-sand polychromatic erythrocytes (PCE) and normochromatic erythrocytes (NCE) were counted under the light microscope, and the number of micronucleated PCEs were recorded. Results : The frequency of micronuclei in PCE (and NCE in parenthesis) in the control group was $0.25{\pm}0.07$ ($0.23{\pm}0.07$)% in day 1 and $0.24{\pm}0.07$ ($0.21{\pm}0.07$)% in day 3. Those in group 1 was $0.27{\pm}0.1$ ($0.23{\pm}0.09$)% in day 1 and $0.28{\pm}0.07$ ($0.25{\pm}0.06$)% in day 3. Micronuclei was noted in $0.29{\pm}0.08$ ($0.26{\pm}0.09$)% in day 1 and $0.31{\pm}0.05$ ($0.29{\pm}0.06$)% in day 3 in group 2, and in $0.32{\pm}0.06$ ($0.25{\pm}0.09$)% in day 1 and $0.33{\pm}0.08$ ($0.3{\pm}0.06$)% in day 3 in group 3. There was no difference in the frequency of micronuclei between each groups (p> 0.05). Conclusion : Radioiodine ($^{131}I$) did not cause any genotoxicity in mice bone marrow even at the large dose (16.67 mCi/kg).

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.148-154
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• 2006

Purpose: Although radionuclide cisternography (RNC) is an useful study to detect cerebrospinal fluid (CSF) leakage in the patient with spontaneous intracranial hypotension (SIH), it sometimes fails to demonstrate the site of CSF leakage. The aim of the study is to improve the detection of leakage site of CSF and to reduce time for the study in RNC using modified protocol (m-RNC). Materials & methods : The study consists of 8 studies of 7 patients ($38{\pm}8$ years, M:F=2:5) with SIH, who underwent m-RNC following administration of 185-222 MBq of $^{99m}Tc$-DTPA into the lumbar subarachnoid space. Sequential images were obtained the whole spine with the head including urinary bladder at 10 minute, 30 minute, 1 hour, 2 hour, 4 hour and 6 hour. Radioactivity of extradural space and urinary bladder was evaluated. Results: Leakage site of CSF was identified in all 8 cases by m-RNC. Leakage site was cervicothoracic junction (CTJ, n=3), CTJ with C1-2 (n=2), CTJ with thoracic spine, thoracolumbar spine and lumbar spine (each n=1). All cases presented leakage sites within 1 hour and multiple sites, where CTJ was included in 6 cases. Only one case presented additional site in 6 hour image. Early radioactivity within the urinary bladder was noted in 6 cases, but that was fellowing after identification of the leakage site. Conclusion: Radionuclide cisternography is sensitive to detect the leakage site of CSF and is expected to improve the detection of CSF leakage site and reduce time for the study using modified protocol.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.328-336
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• 2008

Metal mining district drainage is a well recognized source of environmental contamination. Oxidation of metal sulfides produces acidic and metal-rich waters that contaminate local surface water and ground water in mines, mine dumps, and tailing impoundments. This monitoring study was carried out to investigate the stream water quality and pollution as affected by the Sambo mine drainage in relation to the relative distance from the mine. It obvious that pH values of the mine drainage ranged from 5.8 to 6.9, while the average concentrations of the dissolved chemical constituents for EC, $SO_4^{2-}$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were $1.77\;dS\;m^{-1}$, 929, 14.6, 263.3, and 46.9 mg/L in mine drainage discharged from the main waste rock dumps (WRD), respectively. Furthermore, EC values and sulfate concentrations exceeded the critical toxicity levels in agricultural water for rice plant ($1.0\;dS\;m^{-1}$ for EC and 54.0 mg/L for $SO_4^{2-}$). Also, the average of dissolved cadmium concentrations ($0.016{\sim}0.021\;mg/L$) was higher than water quality standard (0.01 mg/L) for agricultural water in Korea, in addition to Zn, Fe and Mn were higher than trace metals maximum concentrations which recommended by FAO for irrigation water. The results indicate that mine drainage discharged from the Sambo mine affected stream water at least to distance of 1 km downstream of the mine water discharge point. EC values, $SO_4^{2-}$ and $Ca^{2+}$ concentrations in discharged water positively correlated with dissolved Cd, Zn, Al and Mn concentrations, while the pH values negatively correlated. In addition, EC values, $SO_4^{2-}$ and $Ca^{2+}$ concentrations were negatively correlated with pH values.