• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.427-433
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• 2010

Aquatic invertebrates are the major important fauna to sustain the paddy ecosystem as predators of the lower trophic level and prey for birds in food-web dynamics as well. The nationwide distribution of scavenger beetles (Hydrophilidae) that is the top predator in an aquatic insect in the paddy field was investigated. A total of 15 scavenger beetles were recognized. Enochrus simulans (98.6%) and Laccobius bedeli (87.7%) showed a high frequency of occurrence on a nationwide scale. The majority of scavenger beetles were higher frequency of occurrence in mountainous regions(33.7%) than in open field regions(5.0%). On the other hand, E. uniformis, Coelostoma stultum and Berosus japonicus showed a low occurrence frequency. Hydrochara affinis, Sternolophus rufipes, Amphiops mater, B. elongatulus, B. signaticollis punctipennis, B. lewisius and H. libera showed regional specific distribution aspect. Therefore, these species can be used as biological index to research the biotic changes in paddy ecology according to an agro-environmental changes including climatic change in the future.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.39-48
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• 2020

The slender shinner (Pseudopungtungia tenuicorpa), a tiny freshwater fish of about 8 to 10 cm belonging to Cyprinidae, is an endangered species found only in the Han and Imjin Rivers on the Korean Peninsula. During the breeding season, this species spawns in nests of Coreoperca herzi, a predator of this species, or small crevices on rocks. This unique reproductive ecology can make this species more vulnerable to anthropogenic perturbance that can further limit the places to spawn. Here, mtDNA and microsatellite loci were analyzed to identify the genetic diversity and structure of slender shinners and further to provide the basic data necessary for the conservation planning of this species. A total of 28 polymorphic microsatellite markers were developed using Illumina paired-end sequencing, and 67 slender shinners collected from three localities in the Han River were genotyped using these loci. This species showed a remarkably high level of genetic diversity with mean expected heterozygosity of 0.914 and mean allele number per locus of 27.9, and no signature of drastic demographic decline was detected. As a result of our microsatellite analysis, the genetic structure between the two stems of the Han River, North Han and South Han, was prominent. Such a genetic structure was also evident in the sequence analysis of 14 haplotypes obtained from mtDNA control region. Although slender shinners are only found in very limited areas around the world, the genetic structure indicates that there is a block of gene flow among the populations, which should be reviewed in the future if management and restoration of this species is needed.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.747-753
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• 2003

면역글로불린의 Fc 부분에 대한 수용기인 $Fc{\gamma}R$는 세균에 대한 인식, 결합과 포식작용과정에서 중요한 역할을 한다. 이 $Fc{\gamma}R$에서 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb의 유전자 다형성이 치의학 분야에서 연구되고 있다. $Fc{\gamma}R$IIa에서는 두 번째 세포외 면역글로불린 유사 영역의 131번째 아미노산에서 아르기닌($Fc{\gamma}R$IIa-R131) 혹은 히스티딘($Fc{\gamma}R$IIa-H131)을 갖고 있으며, $Fc{\gamma}R$IIIa에서는 두번째 세포외 영역의 158번째 아미노산이 발린($Fc{\gamma}R$IIIa-158V) 혹은 페닐알라닌($Fc{\gamma}R$IIIa-158F)을 갖고 있다. $Fc{\gamma}R$IIIb에서는 첫 번째 세포외 면역글로불린 유사영역의 4개의 아미노산의 유전자 다형성으로 인해서 $Fc{\gamma}R$IIIb-NA1과 $Fc{\gamma}R$IIIb-NA2의 두가지 유전자 다형성을 보이고 있다. 이번 연구는 치주적으로 건강한 한국인에서 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb에 대한 유전자형의 분포를 조사하고자 한 것으로 서울대학교 치과병원에 근무하는 치과의사, 치과위생사, 간호조무사 및 서울대학교 치과대학 4학년 학생 중 치주낭 깊이와 부착소실이 4mm 이하인 치주적으로 건강한 한국인 65명을 대상으로 하였다. $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb의 유전자 다형성은 분리한 DNA에 각 대립유전자에 특이성을 지닌 primer를 넣고 PCR(polymerase Chain Reaction)법을 이용하여 증폭시킨후 전기영동법을 이용하여 각 대립유전자의 존재를 확인함으로써 결정하였다. $Fc{\gamma}R$IIa의 유전자 다형성은 R/R131, R/H131, H/H131의 유전자형에 대하여 각각 7.7%, 38.5%, 53.8%의 분포를 보였으며, $Fc{\gamma}R$IIIa의 158V/V, 158V/F, 158F/F 유전자형에 대하여 각각 7.7%, 35.4%, 56.9%의 분포를 보였다. 또한 $Fc{\gamma}R$IIIb의 NA1/NA1, NA1/NA2, NA2/NA2 유전자형은 각각 33.9%, 53.8%, 12.3%의 분포를 보였다. 이를 바탕으로 각 대립유전자의 발생빈도 계산한 결과 $Fc{\gamma}R$IIa의 R131과 H131이 26.9% 73.1%로 나타났으며, $Fc{\gamma}R$IIIa의 158V, 158F의 유전자형이 25.4%, 74.6%로 나타났다. $Fc{\gamma}R$IIIb의 NA1, NA2 유전자형의 발생빈도는 60.8%, 29.2%로 나타났다. 이번 연구는 치주적으로 건강한 한국인에서의 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb에 대한 유전자형의 분포를 조사한 것으로, 이후 치주질환자의 유전자형 분포와의 비교로 치주질환과 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb의 유전자다형성과의 관련성에 관한 추가적인 연구가 필요할 것으로 여겨진다.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.187-198
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• 2010

Thinning treatment has a huge effect on understory and litter structures in forest ecosystem, and the resulting changes may impact some arthropod groups such as plant-feeders and detritivores. This study was carried out to find a change in arthropod abundance and their structures in relation to the thinning activity in a Pinus koraiensis plantation in Chuncheon, Korea, where thinning was conducted twice: in 1998-2000 (old-thinning) and 2007 (new-thinning). Arthropods were collected using pitfall traps in 2006 and 2008. Effects of old-thinning on change of abundance and community structure of arthropod were significant, but the effects of new-thinning were not significant. The most significant thinning effect was found in detritivores, followed by plant feeders, but the effect was hardly significant in predators. Among detritivores the changes in abundance was diverse. The abundance of orthopteran plant-feeder increased, but Curculionidae declined after thinning. There was not different in abundance of total arthropods between thinned and unthinned areas because the difference may have cancelled each other out by increased or decreased abundance of taxa. Community structures of arthropods were most greatly affected by years, followed by the old-thinning, but the new-thinning did not affect community structures.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.249-255
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• 1995

These experiments were conducted to investigate the life history and the seasonal fluctuation of population density of tea red spider mite, Tetranychus kanzawai Kishida and to observe its natural enemies in the southern area. Under field-cage conditions, tea red spider mite occurred 11~12 generations. The average periods from egg to adult emergence were 8.7~13.1 days in summer and 12.6~24.9 days in spring and autumn. The average longevities of adults were 15.5~21.9 days in summer and 25.1~31.6 days in spring and autumn. The average number of eggs laid per female were 45.1 in summer and 52.6 in spring and autumn. Tea red spider mite population showed two peaks during April-June, and appeared third or forth peak during October-November. The density of all the stages was the lowest in July through August. Tea red spider mites stayed at lower parts of tea plants in March but they moved to upper parts in April though June, and they again moved to lower parts after autumn. Tea red spider mite overwintered as all stages. Adults were the dominant overwintering stage during this stage. The surveyed natural enemies of the tea red spider mite were 7 species including Amblyseius longispinosus (Evans), A. eharai Amitei et Swirski, Anystis baccarun (L), Agistemus fleschneri Summers, Orius sauteri Poppius, Oligota yasumatsui Kistner and Scolothrips sp.

• 한국해양학회지
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• v.19 no.2
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• pp.153-162
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• 1984

This study was conducted to interpret the relations between the polychaete community and its environments in Kwangyang Bay during July, 1982. The type of sediments in the study area varies from sand to clay and the organic content obtained by ignition was in the ranges of 0.3% to 15.4%. The polychaetes which occurred at 25 stations comprised 70 species representing 63 genera and had an average density of 490 animals/m$\^$2/. The most abundant species were Lagis bocki (20%), Lumbrineris longifolia (10%), Chohe teres (7%), and Sternaspis scutata (5%). The polychaete populations show the highest density in muddy sand sediments and have a tendency to decrease their abundance in finer sediments such as bud and clay. The individual numbers of each feeding type show the same tendency. Kwangyang Bay consists of three distinct characteristic communities, representing different physical and biological factors: delta community, muddy flat community and channel community. Delta community has very poor organisms and seems to be determined by physical factors such as tidal current, and by sediment conditions and seems to be determined by physical factors such as tidal current, and by sediment conditions and by the food availability. Muddy flat community shows more diverse and higher abundance than delta community but seems to be impoverished by the stress of oxygen deficiency in sediments. Channel community has the highest density in the study area and comprises more various feeding types. This is probably due to the supply of allochthonous materials from the Seomjin River and offshore as food, the heterogeneous sediments and some biological interactions within habitats.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.245-262
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• 2019

The objectives of this study were to construct a three-dimensional water quality model (EFDC) for the river reach between Chilgok Weir and Gangjeong-Goryong Weir (GGW) located in Nakdong River, and evaluate the effect of hydraulic changes, such as water level and flow velocity, on the control of water quality and algae biomass. After calibration, the model accurately simulated the temporal changes of the upper and lower water temperatures that collected every 10 minutes, and appropriately reproduced changes in organic matter, nitrogen, phosphorus, and cyanobacteria. However, the simulated values were overestimated for the diatoms and green algae cell density, possibly due to the uncertainties of the parameters associated with algae metabolism and the lack of zooplankton predation function in the simulations. As a result of scenario simulation of running the water level of GGW from EL. 19.44 m to EL. 14.90 m (4.54 m drop), Chl-a and algae cell density decreased significantly.In particular,the cyanobacteria on the surface layer, which causes algal bloom, declined by 56.1% in the low water level scenario compared to the existing management level. The results of this study are in agreement with the previous studies that maintenance of critical flow velocity is effective for controlling cyanobacteria, and imply that hydraulic control such as decrease of water level and residence time in GGW is an alternative to limit the overgrowth of algae.

• Korean Journal of Environment and Ecology
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• v.37 no.1
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• pp.70-75
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• 2023

This study was conducted from October 2021 to October 2022 at Gulup island, Incheon, South Korea, to identify activity patterns of Formosan sika deer (Cervus nippon taiouanus) introduced in island areas, using camera trapping. We described the daily activity patterns of Formosan sika deer in each season by analyzing kernel density estimates of capture frequency and checked seasonal differences in daily activity patterns by analyzing the overlap coefficient between seasons. Formosan sika deers introduced to Gulup island showed a crepuscular behavior pattern only in winter and no distinct pattern from spring to fall. The crepuscular behavior pattern is typical for deers to reduce the risk of predation, and it is determined that Formosan sika deers introduced to Gulup island were affected by population control of the species by the local government in the winter. It was in contrast to the fact that human activities, such as backpacking, frequently carried out from spring to fall, did not affect the behavior of Formosan sika deers. Moreover, low winter temperatures have been shown to affect the nocturnal activities of Formosan sika deers in winter. The behavior patterns of Formosan sika deers overlapped least between summer and winter due to cold winter weather and population control. The relationship between the temporal status of Formosan sika deers and seasonal temperature confirmed in this study can be important basic ecological data for establishing control measures of Formosan sika deers introduced not only in islands but also in inland.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.17-23
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• 2002

Purpose : To clarify the clinical benefit derived from the combined modality therapy (CMT) consisting of chemotherapy (CT) and involved field radiotherapy (RT) for stage I and II angiocentric lymphomas of the head and neck. Materials and Methods : Of 143 patients with angiocentric lymphoma of the head and neck treated at our hospital between 1976 and 1995, 104 patients (RT group) received involved field RT alone with a median dose of 50.4 Gy (range : 20~70 Gy), while 39 patients (CMT group) received a median 3 cycles (range : 1~6 cycles) of CT before involved field RT. The response rate, patterns of failure, complications, and survival data of the RT group were compared with those of the CMT group. Results : Despite a higher response rate, local failure was the most common pattern of failure in patients of both groups. The patterns of failure, including the systemic relapse rate were not influenced by the addition of combination CT. Although both modalities were well tolerated by the majority of patients, aberrant immunologic disorders or medical illnesses, such as a hemophagocytic syndrome, sepsis, intractable hemorrhage, or the evolution of second primary malignancies were more frequently observed in patients of the CMT group. The prognosis of patients in the RT group was relatively poor, with a 5-year overall actuarial survival rate of 38% and disease-free survival rate of 32%, respectively. However, their clinical outcome was not altered by the addition of systemic CT. Achieving complete remission was the most important prognostic factor by univariate and multivariate analyses, but treatment modality was not found to be a prognostic variable influencing survival. Conclusions : Involved field RT alone for angiocentric lymphoma of the head and neck was insufficient to achieve an improved survival rate, but the addition of CT to involved field RT failed to demonstrate any therapeutic advantage over involved field RT alone.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.71-85
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• 2018

A recent topic of interest within ecology is ecosystem services that are importantly connected with biodiversity. Biodiversity is a fundamental component of ecological studies and has been the subject of many studies worldwide. However, studies on the diversity and distribution of freshwater fish were not undertaken in earnest until 2000, and the number of internationally available studies is therefore still limited. In this study, we used data from "The Survey and Evaluation of Aquatic Ecosystem Health (hereafter SEAEH)" within the framework of which whole water systems on the Korean peninsula are annually monitored to investigate and determine the current status of the diversity and distribution of freshwater fish, as well as to elucidate major factors impacting freshwater fish. A total of 130 species from 28 families were identified at around 953 sites in the SEAEH investigation of 2014. The species Zacco platypus (relative abundance: 28.2%) and Z. koreanus (19.3%) were identified as the most abundant species on the Korean peninsula, and besides these 20 endangered species, 51 endemic species and 4 exotic species were also collected. Highest (96 species) and lowest (72 species) diversity were identified in the Han River Watershed and the Yeongsan/Seomjin River Watershed, respectively. The mean endemic rate was 32.7%, which is higher than the previous rate determined in 1995. The exotic species Micropterus salmoides, Lepomis macrochirus and Carassius cuvieri were found in the whole river system except north Yeongdong, whereas Oreochromis niloticus occurred only at three sites due to the cold water temperatures in winter. Totally, 28 species were found to be translocated to different water systems not connected with known original habitats, most translocations occurring in the Nakdong River and the Yeongdong region. Among the translocated species, Opsariichthys uncirostris amurensis, and Erythroculter erythropterus were dominantly distributed in the mid- to lower reaches of Nakdong River where they may be harmful to the native fish assemblages due to their strong predation. The construction of weirs in connection with the "4 River Project" generated changes in fish assemblages before, during and after the project, resulting in altered habitat condition. Especially, a decrease in the number of endemic species and an increase in the abundance of lentic species were seen. Human-induced global warming will allow exotic species requiring high water temperatures to adapt to the environmental conditions of the Korean peninsula, which may enhance the diversity of native fishes and create changes in distribution. For the establishment of realistic and efficient management and protection strategies for Korean freshwater fish, SEAEH, which produces fundamental and quantitative data for Korean streams, is an important and necessary tool.