• Journal of Environmental Science International
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• v.27 no.10
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• pp.901-906
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• 2018

Water and oxygen are two of the most essential molecules for many species on earth. Their unique properties have been studied in many areas of science. In this study, the interaction of water and oxygen molecules was observed at the nano-scale. Using molecular dynamics, a water droplet with 30,968 water molecules was simulated. Then, 501 oxygen molecules were introduced into the domain. A few oxygen molecules were attracted to the surface of the water droplet due to van der Waals forces, and some oxygen molecules actually entered the water droplet. These interactions were visualized and quantified at four temperatures ranging from 280 to 370 K. It was found that at high temperatures, there was a higher possibility of the oxygen molecules penetrating the water droplet than that at lower temperatures. However, at lower temperatures, oxygen molecules were more likely to be found interacting at the surface of the water droplet than at high temperatures.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.05a
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• pp.252-254
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• 2004

수영천의 식물상은 모두 38과 68속 82분류군으로 조사되었는데 수영천 본류에서는 75분류군, 온천천에서는 42분류군으로 조사되어 온천천보다는 수영천 본류에서 많은 다양한 종이 출현하였다. 수영천에서 조사된 식물 82종류중 국화과(Compositae) 식물이 10속 14종(17.1%)으로 가장 많이 조사되었고 다음으로 화본과(Gramineae) 식물이 5속 6종(7.3%), 마디풀과 (Pologonaceae) 식물이 2속 5종, 십자화과(Cruciferae) 식물이 5속 5종, 콩과(Leguminosae) 식물이 5속 5종으로 각 6.1%를 차지하으며 기타 41속 47종(57.3%)으로 조사되었는데 다른 하천변 식물의 출현양상과도 유사함을 보였다. 또한 조사된 식물 중 대부분은 수영천 본류의 하천변에서 성장하고 있었으며 온천천에서는 꽃창포(Iris ensatra)를 비롯한 7분류군이 식재되어 외관상 보기에 좋도록 조성되어져 있었고 돼지풀(Ambrosia artemisiifolia var. elatior)을 비롯한 12분류군의 귀화식물이 대부분 온천천에서 자라고 있었다. 도시화의 척도로서 이용되는 도시화 지수(UI)는 수영천 본류에서 25.3%, 온천천에서 28.6%로 다른 하천변의 도시화 지수보다 높게 조사되었다.

• The Korean Journal of Ecology
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• v.13 no.1
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• pp.67-73
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• 1990

The airborne pollens were investigated by 11 pollen traps in Seoul from September to November, 1986 and from March to May, 1987. There were 25 families and 36 genera of which pollens were observed, the amount of airborne pollens was most in May, and least in November. Distribution patterns of ariborne pollens were that of herbs, such as Ambrosia, Artemisia, Humulus, and persicaria in fall, and that of trees, such as Alnus, Salix, Corylus, Pinus, Platanus Betula, and Quercus in spring. From the viewpoint of regional distribution, pollens were much observed at a residential section and an industrial area in fall, and at a park region in spring.

• Journal of Environmental Science International
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• v.22 no.4
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• pp.407-413
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• 2013

The flow of sewage has been studied for hundreds of years. Reducing drag in pipes can allow sewer to be removed easily and quickly. Drag reduction is not only a macroscale issue. Physical and chemical properties of the nano-scale can affect flow at the macroscopic scale. In this paper the predictability of hydrophobicity at the nano-scale is studied. Molecular dynamics simulations were used to calculate the range of contact angles of water droplets in equilibrium on a pillared graphite surface. It was found that at a pillar height of two graphite layers there was the largest range of contact angles. It is observed that at this height the droplet begins to transition from the Wenzel state to the Cassie-Baxter state. Surfaces with larger pillar heights have much larger contact angles corresponding to a more hydrophobic surface. Silicon dioxide was also simulated in the water droplet. The contaminant slight decreased the contact angle of the water droplet.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.39-47
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• 2007

The relationships between the cover of herbaceous species and 15 soil chemical properties (organic carbon contents, total N, available P, exchangeable K, Na, Ca and Mg, HCl-extractable Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in nine poorly controlled waste landfill sites in Korea were examined by correlation analysis and multiple regression equations. Species showed different patterns of correlation between their cover values and soil chemical properties. The cover of Ambrosia artemisiifolia var. elatior, Aster subulatus var. sandwicensis and Erechtites hieracifolia were negatively correlated with the contents of Fe, Mn and Ni within landfill soils. Total cover of all species in quadrats was positively correlated with the contents of Cd and negatively correlated with the contents of Mn and Fe from stepwise regression analysis with 15 soil properties. Canonical correspondence analysis demonstrated that the distribution of native and exotic plants on poorly controlled landfills was significantly influenced by the contents of Na and Ca in soils, respectively.

• Mycobiology
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• v.39 no.4
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• pp.313-316
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• 2011

The ambrosia beetle, Platypus koryoensis, is a serious pest of oak trees in Korea. In this study we investigated filamentous fungi present in the body of the beetle. Fourteen genera of filamentous fungi belonging to Ascomycota and Basidiomycota were isolated. Among the isolated fungi, some were able to produce wood degrading enzymes. This is first report of fungi associated with P. koryoensis.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.131-134
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• 2014

The thermal death kinetics of the Black timber bark beetle, Xylosandrus germanus, was investigated to develop a heat treatment for control of infested wood packing materials used to export goods. To determine the feasibility of microwave irradiation as an alternative control method, laboratory experiments irradiating wooden blocks of Douglas fir ($200{\times}200{\times}250mm$), which were artificially infested with adults, with 2.45 GHz of microwave energy. All (100%) Ambrosia beetle adults were killed by both hot water treatments and microwave irradiation at $52^{\circ}C$ and $58^{\circ}C$, respectively. Probit analyses estimated the internal wood temperature required to produce Probit (0.99) efficacy to be $64.7^{\circ}C$ (95% CI $62.4-69.9^{\circ}C$) at one minute after microwave treatment.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.79-89
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• 2020

This study was performed to evaluate the anti-inflammatory activities of 70% ethanol extract from Ambrosia trifida L. (AT). The electron donating ability and ABTS⁺ radical scavenging ability of extract from AT was shown to be 84.1% and 92.5% at 1,000 ㎍/ml concentration. The astringent effect of extract from AT was shown to be 94.7% at 1,000 ㎍/ml. The anti- inflammatory activities of extract of AT were investigated using RAW 264.7 cells induced by lipopolysaccharide (LPS). The cell toxicity effect of AT extract on RAW 264.7 performed MTT assay. As a result of the measured cell toxicity effect, 90% or more was shown with cell viability at a 500 ㎍/ml concentration. In nitric oxide synthesis inhibition effect, it was shown that extract from AT concentration dependent inhibited nitric oxide production. The protein expression inhibitory effect of AT extract was measured by western blot at 25, 50, and 100 ㎍/ml concentration and the β-actin used as a positive control. Consequently, the inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 protein expression inhibitory effect was decreased by 8.6%, 25.1% at 100 ㎍/ml concentration. The phosphorylation of extracellular signal-regulated kinase 1/2, p38, c-Jun NH₂-terminal kinase and Iκ-Bα protein expression inhibitory effect was a decreased dependent concentration. The mRNA expression inhibitory effect was measured by reverse transcription - polymerase chain reaction at 25, 50, and 100 ㎍/ml concentration and the glyceraldehyde-3-phosphate dehydrogenase used as a positive control. Consequently, the iNOS, COX-2, interleukin (IL)-1β, IL-6 and tumor necrosis factor-α mRNA expression inhibition effect was a decreased dependent concentration in an LPS-activated macrophage. In conclusion, AT extract may have some effects on inflammatory factors as potential anti-inflammatory agents and natural substance for cosmetics.

• The Korean Journal of Ecology
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• v.25 no.3 s.107
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• pp.163-170
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• 2002

In order to analyze the life cycle of A. artemisiifolia var. elatior dormancy and some environmental factors inducing germination of the seeds were examined. The results were as follows : Dormancy of fertile seeds was broken in part within a month after seed collection in case of adequate moisture and alternating temperature was also effective in breaking dormancy. The temperature range, which allow germination was $12^{\circ}C{\sim}32^{\circ}C$. Optimum temperature for germination was $24^{\circ}C$. The seed of A. artemisiifolia var. elatior was light-independent. The difference of storage period appeared to have no particular effect on the viability of seeds at any time during the 9-month storage period. In the increasing temperature(IT) regime, A. artemisiifolia var. elatior seeds started to germinate at $16^{\circ}C$, showing the higher temperature the greater germination rate : the final germination percentage was 99.34%. On the other hand, in the decresing temperature(DT) regime, seeds began to germinate at $20^{\circ}C$ with the 1.34% germination. An induced dormancy occurred at $12^{\circ}C$ making the 5.34% final germination in the DT regime. Low temperature was more effective to break dormancy than higher temperature. Seeds of A. artemisiifolia var. elatior seems to be germinated in mid to late autumn or germination delayed until following spring. The above results suggest these variation of germination response in diverse environmental factors seems to be a physiological strategy to maintain their existence and to reproduce in the extreme thermal variation.

• Korean Journal of Environment and Ecology
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• v.27 no.3
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• pp.280-304
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• 2013

This study was carried out to investigate the flora of Mt. Gilsangsan (Ganghwa-Isl.). The vascular plants were collected 14 times (from March to November 2012), and were identified as 595 taxa; 122 families, 359 genera, 529 species, 7 subspecies, 51 varieties, 2 forms and 3 hybrids. The plant formation of Mt. Gisangsan is the deciduous broad-leaved and conifer mixed forest which is the common one in the middle part of Korean peninsula. All most mountain covered with young secondary forest which is mainly composed of Pinus and Quercus. The family represented by the largest number of species diversity were Asteraceae (11.%), Poaceae (10.7%), Cyperaceae (6.38%), Fabaceae (3.86%) and Rosaceae (3.52%) respectively. Korean endemic plants of this area were 12 taxa; Asarum misandrum, Clematis brachyura, Philadelphus schrenkii, Forsythia koreana, Polygonatum infundiflorum, etc. The red list of vascular plants according to IUCN valuation basis were examined, endangered species (EN) Abies koreana, Near Threatened species (NT) both Wikstroemia trichotoma and Sparganium erectum, Least Concern species (LC) Platycladus orientalis, Swertia diluta var. tosaensis and Iris minutoaurea and by Not Evaluate species (NE) Polygonatum infundiflorum. The floristic regional indicator plants found in this area were 45 taxa comprising two taxa of grade V and VI, nine taxa of grade III, three taxa of grade II, 29 taxa of gradeI. The naturalized plants were identified as 64 taxa and the percent of naturalized index (NI) was 10.7% of total 595 taxa vascular plants. Ecosystem disturbance wild plants were consisted of eight taxa; Rumex acetosella, Sicyos angulatus, Solanum carolinense, Ambrosia artemisiifolia, Ambrosia trifida, Aster pilosus, Hypochaeris radicata and Lactuca scariola. Furthermore, therophytes (26.5%), hemicryptophytes (26.0%), Geophyte (14.0%) showed high proportional ratio in life form spectrum.