• ALGAE
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• 제23권4호
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• pp.277-288
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• 2008

The relationship between nutrients and phytoplankton dynamics was investigated daily from 12 April to 22 July 2003 in Sagami Bay, Japan. According to multidimensional scaling (MDS) and cluster analysis, phytoplankton community was divided into four distinct groups. The first group was consisted of centric diatom species, such as Guinardia spp., Detonula spp., Letocylindrus danicus, Skeletonema costatum, Eucampia zodiacus and Chaetoceros spp.. The second and third clusters comprised mainly diatoms and dinoflagellates, respectively. The other cluster was restricted to the samples collected during the last sampling period when the rainfall and river discharge was frequently recorded. Canonical correspondence analysis (CCA) was applied to analyze four groups respectively, which focused on the effects of nutrients concentration and ratio on phytoplankton variations. Based on CCA analysis, most species of centric diatom were negatively correlated with DSi concentrations and Si/N ratio. Nutrients were strongly limited phytoplankton growth during the summer when the rainfall was not observed, whereas river discharge by rainfall and counterclockwise coastal currents (although the surface circulation pattern is often altered by Kuroshio Current, the counterclockwise coastal currents are generally dominant) has brought phytoplankton population accumulation and triggered the micoalgae growth in western part of the bay. Phosphorous (P) was strongly limited after significantly increases in the phytoplankton abundances. However, silicate (Si) was not a major limiting factor for phytoplankton production, since Si/DIN and Si/P ratio did not create any potential stoichiometric limitation. This indicates that high Si availability contributes favorably to the maintenance of diatom ecosystems in Sagami Bay.

• Animal cells and systems
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• 제5권3호
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• pp.253-262
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• 2001

Ligand-receptor clustering event is the most important step in leukocyte adhesion and spreading on endothelial cells. Intercellular adhesion molecule-1 (ICAM-1) has been shown to enhance leukocyte adhesion, but the molecular event during the process of adhesion is unclear. To visualize the dynamics of ICAM-1 movement during adhesion, we have engineered stable Chinese hamster ovary cell lines expressing ICAM-1 fused to a green fluorescent protein (IC1_GFP/CHO) and examined them under the fluorescence microscopy. The transfection of IC1_GFP alone in these cells was sufficient to support the adhesion of K562 cells that express $\alpha$L$\beta$2 (LFA-1) integrin stimulated by CBR LFA-1/2 mAb. This phenomenon was mediated by ICAM-1-LFA-1 interactions, as an mAb that specifically inhibits ICAM-1-LFA-1 interaction (RRl/l) completely abolished the adhesion of LFA-1＊ cells to IC1_ GFP/CHO cells. We found that the characteristic of adhesion was followed almost immediately (~10 min) by the rapid accumulation of ICAM-1 on CHO cells at a tight interface between the two cells. Interestingly, ICI_GFP/CHO cells projected plasma membrane and encircled approximately half surface of LFA-1+ cells, as defined by confocal microscopy. This unusual phenomenon was also confirmed on HUVEC after adhesion of LFA-1＊ cells. Neither cytochalasin D nor 2,3-butanedione 2-monoxime an inhibitor of myosin light chain kinase blocked LFA-1-mediated ICAM-1 clustering, indicating that actin cytoskeleton and myosin-dependent contractility are not necessary for ICAM-1 clustering. Taken together, we suggest that leukocyte adhesion to endothelial cells induces specialized form of ICAM-1 clustering that is distinct from immunological synapse mediated by T cell interaction with antigen presenting cells.

• 한국균학회지
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• 제10권4호
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• pp.193-202
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• 1982

검정 공팡이의 분화에 따른 균체내의 총 탄수화물 및 trehalose의 함량변화를 연구하였다. 검정 곰팡이를 Czapeck-Dox액체배지로서 진탕배양과 정치배양법에 의해 배양하여 검정 곰팡이의 각 분화과정에서의 균체내의 총 탄수화물 및 trehalose함량을 Trevelyan및 Harison(1955)의 탄수화물분화 및 정량법에 의해 측정하였다. 검정 곰팡이가 포자를 형성할 때에 총 탄수화물의 양이 증가하였고 trehalose는 특히 포자형성 직전에 극적으로 증가하였다. 또한 배지내의 성분함량의 결핍에 따른 탄수화물량의 변화를 연구하기 위해 본 실험에 사용된 Czapeck-Dox 배지내의 질소원, 인산원, glucose 등의 함량의 제한시 검정 곰팡이 분화과정의 각 단체에서의 탄수화물 및 trehalose함량 변화를 실험하였다. 질소원의 함량을 제한할 때, 총 탄수화물과 trehalose양이 기본 배지에서 배양했을 때보다 증가하였다. 인산원 제한시도 총 탄수화물과 trehalose양이 증가하였으나, 질소원 제한 배지에서 배양했을 때 보다는 뚜렷하지 못했다. 굴루코즈 함량제한시는 총 탄수화물 및 trehalose양의 변동을 관찰할 수 없었다. 이들 총 탄수화물 및 trehalose의 함량변동은 검정 곰팡이의 분화와 관련성이 있는 것으로 해석된다.

• 한국제4기학회:학술대회논문집
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• 한국제4기학회 2004년도 추계학술대회
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• pp.37-43
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• 2004

The response of the CCCma coupled climate model to the imposition of LGM conditions is investigated. The global mean SAT and SST decrease by about $10^{\circ}C$ and $5.6^{\circ}C$ in the coupled model. Tropical SST decreases by $6.5^{\circ}C$, whereas CLIMAP reconstructions suggest that the tropics cool by only about $1.7^{\circ}C$, although the larger tropical cooling is consistent with the more recent proxy estimates. With the incorporation of a full ocean component, the coupled model gives a realistic spatial SST pattern, capturing features associated with ocean dynamics that are seen in the CLIMAP reconstructions. The larger decrease of the surface temperature in the model is associated with a reduction in global precipitation rate (about 15%). The tropical Pacific warm pool retreats to the west and a mean La $Ni\tilde{n}a$-like response is simulated with less precipitation over the central Pacific and more in the western tropical Pacific. The more arid ocean climate in the LGM results in an increase in SSS almost everywhere. This is particularly the case in the Arctic Ocean where large SSS increase is due to a decrease in river discharge to the Arctic Ocean associated with the accumulation of snow over the ice sheet, but in the North Atlantic by contrast SSS decreases markedly. This remarkable reduction of SSS in the North Atlantic is attributed to an increase in fresh water supply by an increase in discharges from the Mississippi and Amazon rivers and an increase in P-E over the North Atlantic ocean itself. The discharges increase in association with the wetter LGM climate south of the Laurentide ice sheet and in South America. The fresh water capping of the northern North Atlantic results in a marked reduction of deep convection and consequently a marked weakening of the North Atlantic overturning circulation. In the LGM, the maximum overturning stream function associated with the NADW formation decreases by about 60% relative to the control run, while in the Southern Ocean, oceanic convection is stronger in the LGM due to reduced stratification associated with an increase in SSS and a decrease in SST and the overturning stream function associated with the formation of AABW and the outflow increases substantially.

• Environmental Engineering Research
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• 제11권4호
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• pp.194-200
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• 2006

Recently, the population growth, industrial and agricultural development are rapidly undergoing in the Lower Rio Grande Valley (LRGV) in Texas. The Lower Rio Grande Valley (LRGV) composed of the 4 counties and three of them are interesting for Non-point and point source pollutant modeling: Starr, Cameron, and Hidalgo. Especially, the LRGV is an intensively irrigation region, and Texas A&M University Agriculture Program and the New Mexico State University College of Agriculture applied irrigation district program, projects in GIS and Hydrology based agricultural water management systems and assessment of prioritized protecting stream network, water quality and rehabilitation based on water saving potential in Rio Grande River. In the LRGV region, where point and non-point sources of pollution may be a big concern, because increasing fertilizers and pesticides use and population cause. This project objective seeks to determine the accumulation of non-point and point source and discuss the main impacts of agriculture and environmental concern with water quality related to pesticides, fertilizer, and nutrients within LRGV region. The GIS technique is widely used and developed for the assessment of non-point source pollution in LRGV region. This project shows the losses in $kg/km^2/yr$ of BOD (Biological Oxygen Demand), TN (total Nitrogen) and TP (total phosphorus) in the runoff from the surface of LRGV. Especially, farmers in Cameron County consume a lot of fertilizer and pesticide to improve crop yield net profit. Then, this region can be created as larger nonpoint source area for nutrients and the intensity of runoff by excess irrigation water. And many sediment and used irrigation water with including high nutrients can be discharged into Rio Grade River.

• Journal of Ginseng Research
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• 제34권3호
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• pp.175-182
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• 2010

North American ginseng seedlings (Panax quinquefolius L.) were grown in pots in heated greenhouses, in a cool greenhouse, or in the field, in 11 experiments at various times over 16 years. Crop establishment, dry matter partitioning, photosynthesis, radiation use efficiency and carbon budget were measured and/or calculated in some years. Once the seedling canopy, of about $20\;cm^2$ per seedling, and a leaf area index of 0.37, was established, about 40 days after germination, full canopy display lasted about 87 days. Only 16.6% of the incoming solar radiation was intercepted by the crop, the remainder falling on the mulched soil surface. Total and root dry matter accumulations in the cool greenhouse and in the field were about double that in the heated greenhouses. Partitioning of dry matter to roots (economic yield or harvest index) in the cool greenhouse and in the field was 73% whereas it was 62.5% in the heated greenhouses. The relationship between root dry matter and radiation interception during the full canopy period was linear with growth efficiencies of $2.92\;mg\;MJ^{-1}$ at 4.8% of incoming radiation and $0.30\;mg\;MJ^{-1}$ at 68% of incoming radiation. A photosynthetic rate of $0.39\;g\;m^{-2}\;h^{-1}$ was attained at light saturation of about $150\;{\mu}mol\;m^{-2}\;s^{-1}$ (7.5% of full sunlight); dark respiration was $0.03\;g\;m^{-2}\;h^{-1}$, about 8.5% of maximum assimilation rate. Estimates of dry matter accumulation by growth analysis and by $CO_2$ uptake were similar, 6.21 vs. 7.62 mg $CO_2$, despite several assumptions in $CO_2$ uptake calculations.

• 접착 및 계면
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• 제20권4호
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• pp.155-161
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• 2019

공액분자 나노구조체 계면에서의 전하이동 이방성을 이해하는 것은 유기전계효과트랜지스터(OFET)에서 구조-물성 상관관계를 규명하는데 중요하다. 본 연구에서는 대표적인 코페이셜 적층구조를 가진 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) 유기반도체 단결정과 산화물 계면에서 전하이동도 이방성을 연구하였다. 용매치환공정을 이용해 유기단결정을 산화실리콘 절연체 표면에 성장시키고 유기단결정/산화물 계면에서 전하이동을 유도할 수 있도록 OFET 소자를 완성하였다. TIPS-pentacene OFET에서 최고/최저 전하이동도 이방성은 5.2로 관찰되었다. TIPS-pentacene의 전하이동을 담당하는 공액부의 최인접부와의 상호작용을 분석한 결과, HOMO 준위 커플링과 전하의 호핑 궤도가 전하이동도 이방성에 기여하는 것으로 밝혀졌다. HOMO 준위 커플링에 기반한 전하이동도 이방성의 정량적 예측은 실험결과와 유사하게 나타났다.

• The Korean Journal of Ecology
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• 제26권2호
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• pp.65-70
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• 2003

Shihwa tidal freshwater marsh was constructed recently to treat pollutants entering Shihwa lake. In this study, we examined the spatial and temporal patterns of heavy metal accumulation in soils of Shihwa marsh and sought correlations between several soil variables (pH, electrical conductivity, organic matter, and acid ammonium oxalate-extractable Fe and Al contents) and the heavy metal concentration of soils. Surface soil samples (0∼20 cm) were collected in June 2000, November 2000, and July 2001, and were analyzed for heavy metals (Zn, Cd, Pb, Cu, Cr, As, and Hg) and soil chemical properties. The neutral pH and water-saturated conditions of Shihwa marsh appeared to favor immobilization of heavy metal through adsorption onto soils. The concentrations of heavy metal (especially Zn, Cu, and Cr) in soils of Shihwa marsh increased along the sampling occasions, suggesting that soils of Shihwa marsh serve as a sink of heavy metal. Among the sub-marshes, metal concentrations were highest in Banweol high marshes and lowest in Samhwa marshes. The temporal and spatial variations in the heavy metal concentrations of soils were correlated positively with organic matter and oxalate extractable Fe and Al contents, but negatively with electrical conductivity. These results suggest that organic matter and hydrous oxide of Fe/Al may playa key role in removing heavy metals in soils of Shihwa marsh, and that heavy metal removing capacity would increase with desalinization. However, the removal patterns of heavy metal by reeds warrant further studies to evaluate the total removal capacity of heavy metals by Shihwa marsh.

• 한국동물학회지
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• 제31권3호
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• pp.207-217
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• 1988

배양 계배 근원세포의 분화에 미치는 계배추출물의 영향을 조사하고, 이 추출물로부터 근워세포의 분화에 필수적인 myotrophic protein(MP)를 순수분리하였다. 그리고 이 MP는 철 운반 단백질인 trsnaferrin과 동일하거나 또는 대단히 유사한 단백질임을 알 수 있었다. 이 단백질은 철을 근원세포에 공급하고 이 철근이 근원세포의 융합에 필수적인 역할을 하는 것으로 보인다. 또 계배추출물속에는 이 MP이외에 근원세포의 융합을 억제하는, 그리고 열에 비교적 안정한 단백질이 존재하다고 생각된다. 이 MP의 수용체(receptor)분석을 한 결과, 수용체의 수는 근원세포가 융합을 하고 나면 급속히 감소하는 것으로 나타났다. 그리고 근원세포의 내로의 철과 MP의 수송에는 약 10분이 소요되는 것으로 나타났다.

• Journal of Magnetics
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• 제8권4호
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• pp.138-141
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• 2003

$Ni_{0.65}Zn_{0.35}Fe_2O_4$thin films were prepared by using a sol-gel method. Their crystallographic, dielectric and magnetic properties were investigated as a function of Cu contents by means of an X-ray diffractometer (XRD), X-ray reflectivity, LCZ meter (NF2232), a vibrating sample magnetometer (VSM), and an atomic force microscope (AFM). From typical C-V measurements for $Ni_{0.65}Zn_{0.35}Fe_2O_4$ thin films on p-type silicon substrate, the surface charge density was calculated as 1.4 ${\mu}$C/$m^2$. The dielectric constant evaluated from the capacitance at the accumulation state was 28. The high $H_{c}$ and low $M_{sat}$ at x=0.0 and 0.1 were due to the growth of the ${\alpha}$-$Fe_2O_3$ phase having antiferromagnetic properties. The rapidly decreased $H_{c}$ and increased $M_{sat}$ at x=0.2 and 0.3 can be explained that the ${\alpha}$-$Fe_2O_3$ phases have completely disappeared at x=0.3 and so, non-magnetic defects are minimized. The $M_{sat}$ was slightly decreased and the $H_{c}$ was increased above at x=0.3 because the increase of grain boundary due to smaller grain size acts as defects during magnetization process.