• Korean Journal of Veterinary Pathology
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• v.6 no.2
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• pp.101-104
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• 2002

닭의 전신장기에 림프종 발생이 특정인 마렉병(Marek's disease; MD)은 림프구성 백혈병(Lymphoid leukosis; LL)과 병리학적 소견이 매우 유사하여 감별이 요구된다. 마렉병 바이러스(Marek's disease virus; MDV)는 질병초기에서 후기에 이르기까지 모낭상피세포에 세포용해성 감염을 지속적으로 일으킨다. 세포용해성 감염이 있는 모낭상피세포는 변성내지 괴사되어 있고 핵내봉입체가 관찰된다. 또한 세포용해성 감염이 있는 모낭상피세포 바로 밑의 진피와 깃털 수질(feather pulp)내의 혈관주위에 림프구 침윤이 관찰된다. 이러한 피부병변은 MD의 특징적인 병변들로서 LL과 감별할 수 있는 결정적인 단서이다. 본 고에서는 MD에 관한 전반적인 것과 특히 MD 진단을 위한 피부병변의 유용성에 대해서 자세히 논하고자 한다. 양계산업에 문제를 야기하고 있는 림프구 증식성 종양은 크게 마렉병(Marek’s disease; MD)과 백혈병(Lymphoid leukosis; LL)이 있다. 이들 질환의 원인체들이 분리되기 전까지는 이들 질병들은 발병부위에 따라 질병명을 붙였다. 즉, 내부장기냐 근육에 발생한 것은 visceral lymphomatosis, 피부에 발생한 것은 skin leukosis, 말초신경의 병변은 poly­n neuritis, neuritis, neurolymphomatosis gallinarum, range paralyis로 불리었다. 또한 눈에 발생한 것은 blindness, gray eye, iritis, uveitis, ocular lymphomatosis라고 불리었다. 1961년에 Biggs는 이러한 림프구 증식성 질병을 마렉병과 백혈병 으로 분류하자는 제안을 하였고, 드디어 1960년대 중반에 림프구 증식성 병변 중의 일부에서 herpesvirus가 분리되어서 Biggs가 제안한 병명인 마렉병을 본격적으로 사용하게 되었다. MD는 마렉병 바이러스(Marek’s disease virus; MDV)가 원 인제로서 닭에 전염성이 강한 염증성에서 종양성의 병변을 내부장기, 피부, 근육, 안구, 중추신경계, 말초신경계 등에 일 으킨다. MDV는 림프종을 유발하기 때문에 처음에는 사람에서 림프종을 유발하는 Epstein-Bar 바이러스와 관련이 있을 것으로 생각되어 gamma-herpesvirus로 분류되었지만, MDV의 게놈 구조와 세포배양에서 빠르게 성장한다는 점 때문에 지금은 alpha-herpesvirus로 재분류 되었다. MDV는 바이러스 중화시험과 한천 겔 침강법에 의해서 3개의 혈청형으로 분류 된다. 혈청형 1은 종양원성 바이러스와 종양원성 바이러스의 계대배양에 의한 약독주가 있다. 혈청형 2는 자연적으로 발 생하는 비종양원성 닭의 MDV이고, 혈정형 3은 바종양원성 칠면조 herpesvirus (HVT)이다. 림프종을 유발하는 MDV 감염은 4개의 과정, 즉 초기 세포용해성 감염, 잠복감염, 후기 세포용해성 감염, 마지막으로 종양화로 나눌 수 있다. 감염의 경로를 보면, 흡입된 MDV는 폐의 대식세포에 감염한 후 전선 장기로 MDV를 전파 시킨다. 특히, 흉선, F냥, 비장 등의 림프구에 초기 세포용해성 감염을 일으키는데, B 림프구가 주로 감염된다. 세포용해성 감염음 방어하기 위해 몰려든 T 림프구가 활성화가 되면, T 세포도 감염되게 된다. 잠복감염은 여러 가지 사이토카인 등 을 포함한 면역반응에 의해서 일어나며, 이 때 잠복감염된 세포는 특히 혈중의 T 세포라고 한다. 혈중 MDV 감염세포 는 피부 모낭상피세포, 선장 등 상피세포 유래의 조직에 MDV를 전파 시켜서 이들 조직에서 후기 세포용해성 감염이 일어나게 한다. 후기 세포용해성 감염을 유발하는 것은 이러한 MDV가 감염된 혈중 림프구라는 증거는 혈중의 세포 외에는 감염성 바이러스가 없기 때문이다. 후기 세포용해성 감염이 있는 후 육안적 혹은 현미경적으로 검출이 가능한 림프종이 여러 장기에서 관찰된다. MDV가 감염되면 병변 발생부위에 따라서 다양한 임상증상이 발생한다. 즉 내부장기에 병변이 있을 경우는 침울, 체중감소, 산란율 저하 등이 발생하며, 신경계는 발생부위별 신경증상이 일어난다. 이러한 장기나 조직에서는 육안적으로 백색에서 회백색의 종양성 병변이 관찰된다. 말초신경에 병변이 발생한 경우에는 특히 좌골신경 및 신경총에서 호발하는데, 이들 조직은 편측성 혹은 양측성으로 종창되어 있다. 안구는 간혹 육안적으로 식별이 가능한 홍채 퇴색 및 증식 병변이 관찰된다. 피부형 MD는 특히 육용계에서 문제가 되고 있으며, 산란계의 내장형 MD가 발생한 경우에도 피부를 자세히 설펴보면 피부형 MD를 간혹 관찰할 수 있다. 피부형 MD는 모낭주위에 원형의 결절형태로 발생하는데, 이들 병변이 커지면 바로 옆의 병변과 융합 되어 큰 결절을 형성하기도 한다. (중략)

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.331-340
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• 2000

The existing two-phase biological fluidized bed has some problems such as limit of oxygen transfer and blockade of fluidized distributor. In this study, three-phase swirl flow biological fluidized bed has designed to solve the problems and to investigate its running characteristics. TOC of influent synthetic wastewater was approximately $70mg/{\ell}$. HRT of reactor was 1.6 hours. Mean particle size of sand, as packing media, was 0.397mm and packing volume was varied from $200m{\ell}/{\ell}$ to $600m{\ell}/{\ell}$ by stages in the bed. The amount of biomass and effluent water quality was throughly investigated in the bed. Showing experiment results from the above conditions, it was possible to solve the problems of existing fluidized bed and to keep DO of $3mg/{\ell}$ or more. And it was also TOC removal rate of 91 to 94 %, MLVSS of 2,360 to $3,860mg/{\ell}$, MLVSS per g-media of 8.4 to 17.3 mg/g, F/M ratio of 0.59 to $1.04kg-TOC/kg-MLVSS{\cdot}day$, biofilm thickness of $35{\sim}71{\mu}m$ and sludge productivity of 1.03 to $2.35kg-SS/m^3{\cdot}day$. Optimal conditions in this experimental were as follows.; those were biofilm thickness of approximately $54{\mu}m$. MLVSS per g-media of 13 mg and media packing volume of 350 to $400m{\ell}/{\ell}$ when F/M ratio was low, treatment efficiency was high and sludge productivity was low. Showing the media with optics microscope in this optimal condition, attached microbes such as Epistylis sp. were observed. From SEM photographs, it showed that Coccus adhere to and grow on the media surface.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.172-178
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• 2013

The strains were added to the feed in the concentration of $10^3$, $10^5$, and $10^7$ CFU/kg and 2% of fishes were given the feed twice a day (8 AM and 5 PM) for 12 weeks. In result of the nonspecific immune response study to examine Respiratory burst activity, Lysozyme activity and Phagocytosis activity every two weeks until the end of the study, all test samples showed greater activities than control samples and improved immune activity with Bacillus sp. IS-2. The mortality test performed by artificial infection using Streptococcus iniae, a pathogenic bacterium, after the completion of this study also showed over 55% greater survival rate in all test samples. In result of performing PCR using the universal primer to verify that the probiotic stays in the intestines of the fishes, all test samples showed PCR product of 1,465 bp. Based on the above findings, it was concluded that Bacillus sp. IS-2 in the feed improved farmed flatfish's immune system and resistance against diseases as the probiotics. Also, the physiological indicators discovered by this study would be useful for identifying the mechanisms of probiotics.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.228-236
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• 2015

Urbanization causes many environmental, hydrological and ecological problems such as distortion of the natural water circulation system, increase in nonpoint source pollutants in stormwater runoff, degradation of surface water quality, and damage to the ecosystem. Due to the increase in impervious surface by urbanization, developed countries apply low impact development (LID) techniques as important alternatives to reduce the impacts of urbanization. In Korea, LID techniques were employed since 2012 in order to manage nonpoint source pollutants. LID technology is a technique for removing pollutants using a variety of physical, chemical and biological mechanisms in plants, microorganisms and filter media with the reduced effluence of stormwater runoff by mimicking natural water circulation system. These LID facilities are used in a variety of filter media, but an assessment has not been carried out for the comprehensive comparison evaluation of adsorption and desorption characteristics for the pollutant removal capacity. Therefore, this study was conducted to analyze the adsorption and desorption characteristics of various filter media used in the LID facilities such as sand, gravel, bioceramic, wood chips and bottom ash etc. in reducing heavy metals(Pb, Cu). In this study, the adsorption affinity for Pb in all filter media was higher than Cu. Pseudo second order equation and Langmuir-3 isotherm are more applicable in the adsorption kinetic model and adsorption isotherm model, respectively. As a result of the desorption experiment, the filter media does not exceed KSLT which is the hazardous substance leaching limit, showing the capability of the filter media in LID. The bioceramic and woodchip as filter medias were evaluated and exhibited excellent adsorption capacity for Pb.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.66-73
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• 2004

As one of the typical farming practices in the sloped upland in Pyeongchang and Hongcheon area, application of piling with coarse saprolite materials has been practiced by farmers for several reasons such as reduction of damage by monocropping, better development of plant roots, and better drainage. However, adverse effect on application of coarse saprolite soil materials to environmental aspects should not be ignored. Therefore, this research was conducted to evaluate the physicochemical properties of coarse saprolite materials in upland fields in Pyeongchang area. According to particle size distribution of coarse saprolite materials, averaged gravel contents for Pyeongchang and Hongcheon county were 16.7 and 25.3%, respectively. There was no significant difference in gravel contents by soil depth, and CV values for each particle size ranged from 20 to 40%, which implied that application of coarse material with similar properties. When we compared CEC values of dressed soil with or without considering gravel content, CEC values decreased as increasing gravel contents. The penetration resistances were 0.04-7.48 MPa at the 0 to 10 cm surface soil, and 0.10 to 8.80 MPa at the depth below 11 cm. The bulk density of the soil was $1.15g\;cm^{-3}$ at the surface soil and 1.29 to $1.35g\;cm^{-3}$ at the soil depth below 10 cm. The organic matter content, cation exchange capacity, and avaliable $P_2O_5$ concentrations of soil in upland where piling with saprolite materials of Pyeongchang area applied were $12.4g\;kg^{-1}$, $7.1cmol_c\;kg^{-1}$, and $526mg\;kg^{-1}$, respectively. Cation exchange capacity was lower than that of averaged Korean upland soil, while available $P_2O_5$ concentration was relatively higher than that of averaged Korean upland, which indicated high input of various fertilizers.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.278-286
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• 2010

Veterinary antibiotics have been used to treat disease and to promote growth of livestock. However, the total amount of veterinary antibiotics in Korea was much greater than other developed countries, and there is a high potential to release residual of antibiotics to environment. Consequentially, released antibiotics into the environment produces antibiotic resistant bacteria and causes adverse effects on human health. The objective of this research was to monitor antibiotic concentration in the environment adjacent to facilities which compose chicken manure. Total of 10 antibiotics were selected based on the total amount of higher usage in Korea, and its residuals were measured from surface water, soil and sediment. The frequencies of detected antibiotics were ranged 31-92% from soil, 0-93% from water, and 33-93% from sediment. Generally, a higher frequency was observed in soil or sediment than water. Different ranges in concentration among 4 different antibiotic groups was found from not detected(N.D.) to 35.6 ${\mu}g/kg$ for soil, N.D. to 19.2 ${\mu}g/L$ for water and N.D. to 114.3 ${\mu}g/kg$ for sediment. Our findings suggest that solid phase such as soil and sediment is a critical component to be needed to conduct the environmental impact assessment of antibiotics.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.795-802
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• 2013

According to the increase of impervious area due to the town development, the rate of infiltration generally lessens and that of runoff rises during wet weather events. And it is concerned that its impacts on water quality for the downstream water bodies due to the change of rainfall runoff patterns may also increase. To cope with these issues, LID (Low Impact Development) techniques which try to maintain the characteristics of rainfall runoff regardless of the town development have been introduced actively. However, the behaviors of each LID technique for rainfall runoff and pollutant loads is not understood sufficiently. In this study, considering the applications of some LID techniques, several sets of simulations using a distributed rainfall runoff model, SWMM-LID, have been conducted for D town whose development is progressing. As the results of the simulations, the rates of infiltration/storage have been decreased from 78% in the case before the town development to 15% after the development and increased again by 24% with LID techniques such as porous pavement, rain barrel and rain garden. The rates of runoff have been increased more than three times from 20% in the case before the development to 74% after the development, and they have also been decreased to 66% by the adoption of LID techniques. It has been simulated that porous pavement is more effective than others in the view point of the reduction of runoff and rain barrel is more attractive for the management of pollutant loads (TSS, BOD, COD, T-N and T-P). Therefore, if some LID techniques should be selected for the a new town, it could be concluded that some techniques with better infiltration functions are recommendable for the control of runoff, and ones with larger storage functions for the management of pollutant loads.

• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.271-282
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• 2020

Sewage treatment plants are social infrastructure of cities. The sewage distribution rate in Korea is reaching 94% based on the sewage statistics based in the year of 2017. In Korean sewage treatment plants, use of PAC (Poly Aluminum Chloride) accounts for 58%. It contains a large amount of impurities (heavy metal) according to the quality standards, however, there have been insufficient efforts to reinforce the standards or technically improve the quality, which resulted in secondary pollution problems from injecting excessive coagulant. Also, the increase in the use of chemicals is leading to the increases in the annual amount of sewage sludge generated in 2017 and the need to reuse sludge. As such, this study aims to verify the possibility of reusing sludge by evaluating the stability of heavy metals based on the injection of coagulant mixture during water treatment which uses the torrefield wood powder and natural materials, and evaluating the sedimentation and heating value of sewage sludge. As a result of analyzing heavy metals (Cr, Fe, Zn, Cu, Cd, As, Pb, and Ni) from the coagulant mixture and PAC (10%), Cr, Cd, Pb, Ni, and Hg were not detected. As for Zn, while its concentration notified in the quality standards for drinking water is 3 mg/L, only a small amount of 0.007 mg/L was detected in the coagulant mixture. Maximum amounts of over double amounts of Fe, Cu, and As were found with PAC (10%) compared to the coagulant mixture. Also, an analysis of sludge sedimentation found that the coagulant mixture showed a better performance of up to double the speed of the conventional coagulant, PAC (10%). The dry-basis lower heating value of sewage sludge produced by injecting the coagulant mixture was 3,378 kcal/kg, while that of sewage sludge generated due to PAC (10%) was 3,171 kcal/kg; although both coagulants met the requirements to be used as auxiliary fuel at thermal power plants, the coagulant mixture developed in this study could secure heating values 200 kal/kg higher than the counterpart. Therefore, utilization of the coagulant mixture for water treatment rather than PAC (10%) is expected to be more environmentally stable and effective, as it helps generating sludge with better stability against heavy metals, having a faster sludge sedimentation, and higher heating value.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.226-235
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• 1996

This pot experiment was conducted to investigate the changes of leaching in percolated water of paddy soil in which rice was cultivated in conditions of 0%, 5%. 30% addition of bituminous and anthracite fly ash respectively in greenhouse. pH in percolated water was higher in non cultivated plot than in cultivated plot. pH of the fly ash treated plot was higher than that of the control plot. pH in the cultivated plot decreased gradually during the cultivation. The contents of $NH_4-N$, $NO_3-N$ and K in percolated water decreased rapidly after mid-July, and was very low in the cultivated plot. Over the cultivation time, P contents in percolated water was very low. $SiO_2$, contents in percolated water decreased rapidly after June. Na contents in percolated water was highest in mid-June and then decreased gradually. In the cultivated plot, Ca contents in percolated water was higher than that in the control plot. During the cultivation, Ca contents in percolated water decreased gradually. But, in later-term of cultivation. Ca contents in percolated water was relatively Mgh. Mg contents in percolated water decreased after mid-July, but decreased continuously till the later-term of cultivation. EC in the percolated water was highest in mid-June. and then decreased gradually. EC of fly ash treated plot was higher than that of the control plot. The soil pH was increased and phosphate content in the soil was accumulated very high by application of fly ashes in paddy field after rice cultivation. Fly ash treatment did not increase the contents of elements in percolated water compared with the control plot. The difference between anthracite and bituminous fly ash was not so clear. Fly ash treatment, inhibited early growth and tillering. But, in later-term of cultivation, the inhibition effects of nonproductive tillering was expected. Fly ash treatment will be good if it was applicated after last year's harvest because leaching would happen over fallowing time. Contents of inorganic elements in percolated water of fly ash treated plot was not so high compared with that in the control plot.

• Journal of Aquaculture
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• v.17 no.2
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• pp.144-150
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• 2004

This experiment was conducted to evaluate the parameters such as nutrient requirements, POY, AnV, Totox, VBN, total plate count, dietary fatty acids and amino acids composition, that are not included in the registered standard composition items required by the Ministry of Agriculture and Forestry, of a moist pellet (MP), three domestic extruded pellets (DEP-1, DEP-2, DEP-3), and two foreign extruded pellets (FEP-1, FEP-2) that are utilized by domestic flounder farms at present. The crude protein was added in excess of the dietary protein requirement in 6 kinds of feeds. When considering the proper PH ratio, it is obvious that protein was added in excess, especially in MP and FEP-2. Crude fat was also added in excess, especially in FEP-1. MP contained a higher dietary phosphorus content than formulated feeds, surpassing the dietary phosphorus requirement and greatly increasing the possibility for causing water pollution. The oxidation of fatty acid and decomposition of protein in MP were higher than in formulated feeds, and may also cause problems on fish farms. Also, it is difficult to store and manage MP, Among the fatty acids, EPA and DHA contents in MP were higher than those in formulated feeds. It is necessary to conduct further studies of EPA and DHA contents in formulated feeds. Lysine content in MP and FEP-2 could meet the dietary lysine requirement of flounder, however, the possibility of insufficient lysine content in the other formulated feeds was high and we considered that extra supplementation was necessary. Therefore, it is necessary to set up quality control standards according to fish species and sizes while considering the specific character of aquatic formulated feeds to restore the confidence of feed companies and aquaculturists to these feeds. This may be an opportunity to make an earlier change from MP to formulated feeds.