• Title/Summary/Keyword: Asan Bay

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Influence of Cilnidipine on Catecholamine Release in the Perfused Rat Adrenal Medulla

  • Woo, Seong-Chang;Baek, Young-Joo;Lim, Dong-Yoon
    • The Korean Journal of Physiology and Pharmacology
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    • v.8 no.5
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    • pp.265-272
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    • 2004
  • The present study was attempted to investigate the effect of cilnidipine (FRC-8635), which is a newly synthesised novel dihydropyridine (DHP) type of organic $Ca^{2+}$ channel blockers, on secretion of catecholamines (CA) evoked by acetylcholine (ACh), high $K^+$, DMPP and McN-A-343 from the isolated perfused rat adrenal gland. Cilnidipine $(1{\sim}10{\mu}M)$ perfused into an adrenal vein for 60 min produced relatively dose- and time-dependent inhibition in CA secretory responses evoked by ACh $(5.32{\times}10^{-3}M),\;DMPP\;(10^{-4}M\;for\;2\;min)$ and McN-A-343 $(10^{-4}M\;for\;2\;min)$. However, lower dose of cilnidipine did not affect CA secretion by high $K^+\;(5.6{\times}10^{-2}\;M)$, higher dose of it reduced greatly CA secretion of high $K^{+}$. Cilnidipine itself did fail to affect basal catecholamine output. In the presence of cilnidipine $(10{\mu}M)$, the CA secretory responses evoked by Bay-K-8644 $(10{\mu}M)$, an activator of L-type $Ca^{2+}$ channels and cyclopiazonic acid $(10{\mu}M)$, an inhibitor of cytoplasmic $Ca^{2+}$-ATPase were also inhibited. Moreover, ${\omega}-conotoxin\;GVIA\;(1{\mu}M)$, a selective blocker of the N-type $Ca^{2+}$ channels, given into the adrenal gland for 60 min, also inhibited time-dependently CA secretory responses evoked by Ach, high $K^+$, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid. Taken together, these results demostrate that cilnidipine inhibits CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors from the isolated perfused rat adrenal gland without affecting the basal release. However, at lower dose, cilnidipine did not affect CA release by membrane depolarization while at larger dose inhibited that. It seems likely that this inhibitory effect of cilnidipine is exerted by blocking both L- and N-type voltage-dependent $Ca^{2+}$ channels (VDCCs) on the rat adrenomedullary chromaffin cells, which is relevant to inhibition of both the $Ca^{2+}$ influx into the adrenal chromaffin cells and intracellular $Ca^{2+}$ release from the cytoplasmic store. It is thought that N-type VDCCs may play an important role in regulation of CA release from the rat adrenal medulla.

Trends of Phytoplankton Community and Water Quality and Implications for Management in Estuarine River Systems (국내 연안 하구역의 식물플랑크톤 생체량 (chlorophyll a) 및 수질 동향)

  • Lee, Chang-Hee;Cho, Ki-An;Song, Eun-Sook;Sin, Yong-Sik
    • Korean Journal of Ecology and Environment
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    • v.38 no.2 s.112
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    • pp.160-180
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    • 2005
  • Long-term data (Ministry of Environment Water Quality Monitoring data) of phytoplankton biomass (chlorophyll a) and water quality were analyzed to investigate trends in biomass of the primary producers and water quality for the estuarine systems in Korea: Sumjin River, Han River, Asan Lake- Bay, Youngsan River, Keum River and Nakdong River. The literatures were also reviewed to examine the characteristics of phytoplankton biomass and water quality in the estuarine systems. The Sumjin River estuary, the single estuary without a dike in Korea showed the characteristics similar to other typical estuarine systems. Phytoplankton biomass was high during the fall at transitional regions (5 ${\sim}$ 15 psu) after riverine freshwater inputs were increased in summer. Concentrations of the nitrate and silicate were increased with the high river discharge rates. Phytoplankton biomass and nutrient concentrations were high during spring at the lower regions in the Han River whereas phytoplankton biomass and nutrient concentrations were high during spring at the upper regions in the Youngsan River. Phytoplankton biomass was the highest in the Asan Lake and nutrient concentrations were high at the upper region of the lake. In Nakdong River, phytoplankton biomass was high during winter and the biomass was slightly higher at upper region than at lower region. Long-term trends showed that total nitrogen and total phosphorus were mostly increased in the river systems. Implications of these results relevant to the water quality management for the river systems were also discussed.

Studies on the Influence of Sample thickness, Load Increment Ratio and Load Increment Duration on Consolidation Characteristics. (시료의 두께, 하중증가율 밀 재하시간이 압밀특성에 미치는 영향)

  • 류능환;강예묵
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.20 no.3
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    • pp.4750-4770
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    • 1978
  • Under the various variations of the sample thickness, the load increment ratio and the load increment duration, this consolidation test of the clay in the Asan Bay was tried for the comparison with the standard consolidation test. The results gained are as follows; 1. The void ratio variations of the leached-clay samples were increasingly high, according as the sample thickness thinned and the load increment duration and the laod increment ratio increased. 2. The coefficient of consolidation were increased with the increment of the sample thickness, of the load increment ratio and of the load increment duration. Near the pre-consolidation load, the coefficient of secondary consolidation had the maximum value and lessened with the increment of the sample thicknss, and of the load increment duration 3. The value of the pre-consolidation load increased in proportion to the increment of the sample thickness and the decrease of the load increment ratio and the load increment duration. 4. The compression indices increased as the increment of load increased and decreased as the sample thickness increased. 5. The initial compression ratio increased as the sample thickness, the load increment ratio and the load increment duration decreased. The ratio of primary compression to the secondary decreased with the increment of the sample thickness and of the load increment ratio. 6. The time at the completion of psimary consolidation increased with the increment of the sample thickness and of the consolidation load, and with the decrease of the load increment ratio. 7. The compression indicses increaed as the sample thickness lessened and decreased as the load increment ratio increased. The coefficient of consolidation increased according as the sample thickness, the load increment ratio and the load increment duration went up. The settlement at the construction site should be calculated highly in proportion as the sample thickness lessened and the load increment ratio increased. The consolidation ratio is thought to be accelerated if the sample thickness and the load increment ratio becomes higher and the load increment duration longer.

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AQUACULTURE FACILITIES DETECTION FROM SAR AND OPTIC IMAGES

  • Yang, Chan-Su;Yeom, Gi-Ho;Cha, Young-Jin;Park, Dong-Uk
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.320-323
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    • 2008
  • This study attempts to establish a system extracting and monitoring cultural grounds of seaweeds (lavers, brown seaweeds and seaweed fulvescens) and abalone on the basis of both KOMPSAT-2 and Terrasar-X data. The study areas are located in the northwest and southwest coast of South Korea, famous for coastal cultural grounds. The northwest site is in a high tidal range area (on the average, 6.1 min Asan Bay) and has laver cultural grounds for the most. An semi-automatic detection system of laver facilities is described and assessed for spacebome optic images. On the other hand, the southwest cost is most famous for seaweeds. Aquaculture facilities, which cover extensive portions of this area, can be subdivided into three major groups: brown seaweeds, capsosiphon fulvescens and abalone farms. The study is based on interpretation of optic and SAR satellite data and a detailed image analysis procedure is described here. On May 25 and June 2, 2008 the TerraSAR-X radar satellite took some images of the area. SAR data are unique for mapping those farms. In case of abalone farms, the backscatters from surrounding dykes allows for recognition and separation of abalone ponds from all other water-covered surfaces. But identification of seaweeds such as laver, brown seaweeds and seaweed fulvescens depends on the dampening effect due to the presence of the facilities and is a complex task because objects that resemble seaweeds frequently occur, particularly in low wind or tidal conditions. Lastly, fusion of SAR and optic spatial images is tested to enhance the detection of aquaculture facilities by using the panchromatic image with spatial resolution 1 meter and the corresponding multi-spectral, with spatial resolution 4 meters and 4 spectrum bands, from KOMPSAT-2. The mapping accuracy achieved for farms will be estimated and discussed after field verification of preliminary results.

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Economic Analysis for a Tidal Power Plant Project using RETScreen - Focused on the Tidal Power Plant in Asan Bay (RETScreen을 활용한 조력발전 개발사업 경제성 분석 - 아산만 조력발전소 사례를 중심으로 -)

  • Kim, Min-Ock;Jeong, Keun-Chae
    • Korean Journal of Construction Engineering and Management
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    • v.14 no.4
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    • pp.152-163
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    • 2013
  • In this research, we analyse the economic feasibility of a tidal power plant project which can efficiently generate mass, permanent, predictable, and homogeneous electric power. For the economic feasibility analysis, we used the RETScreen that is developed at the CANMET Energy Technology Center in Natural Resources Canada and widely utilized for analysing the economic feasibility and sensitivity of clean energy projects. Results from the feasibility and sensitivity analysis showd that the tidal power plant project in Korea has a enough economic feasibility, and its feasibility increases more as certified emission reductions price and electricity unit price increase. Based on the results from the feasibility study, we can solve the energy problems to be come in near future by constructing the tidal power plants in Korea more aggressively.

연안 항행안전 위험시설 정보 취득 및 활용 기법

  • Yang, Chan-Su
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2009.10a
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    • pp.73-74
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    • 2009
  • This study attempts to establish a system extracting and monitoring cultural grounds of seaweeds (lavers, brown seaweeds and seaweed fulvescens) and abalone on the basis of both KOMPSAT-2 and Terrasar-X data. The study areas are located in the northwest and southwest coast of South Korea, famous for coastal cultural grounds. The northwest site is in a high tidal range area (on the average, 6.1 m in Asan Bay) and has laver cultural grounds for the most. An semi-automatic detection system of laver facilities is described and assessed for spaceborne optic images. On the other hand, the southwest cost is most famous for seaweeds. Aquaculture facilities, which cover extensive portions of this area, can be subdivided into three major groups: brown seaweeds, capsosiphon fulvescens and abalone farms. The study is based on interpretation of optic and SAR satellite data and a detailed image analysis procedure is described here. On May 25 and June 2, 2008 the TerraSAR-X radar satellite took some images of the area. SAR data are unique for mapping those farms. In case of abalone farms, the backscatters from surrounding dykes allows for recognition and separation of abalone ponds from all other water-covered surfaces. But identification of seaweeds such as laver, brown seaweeds and seaweed fulvescens depends on the dampening effect due to the presence of the facilities and is a complex task because objects that resemble seaweeds frequently occur, particularly in low wind or tidal conditions. Lastly, fusion of SAR and optic spatial images is tested to enhance the detection of aquaculture facilities by using the panchromatic image with spatial resolution 1 meter and the corresponding multi-spectral, with spatial resolution 4 meters and 4 spectrum bands, from KOMPSAT-2. The mapping accuracy achieved for farms will be estimated and discussed after field verification of preliminary results.

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The Presence of Neural Stem Cells and Changes in Stem Cell-Like Activity With Age in Mouse Spiral Ganglion Cells In Vivo and In Vitro

  • Moon, Byoung-San;Ammothumkandy, Aswathy;Zhang, Naibo;Peng, Lei;Ibrayeva, Albina;Bay, Maxwell;Pratap, Athira;Park, Hong Ju;Bonaguidi, Michael Anthony;Lu, Wange
    • Clinical and Experimental Otorhinolaryngology
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    • v.11 no.4
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    • pp.224-232
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    • 2018
  • Objectives. Spiral ganglion neurons (SGNs) include potential endogenous progenitor populations for the regeneration of the peripheral auditory system. However, whether these populations are present in adult mice is largely unknown. We examined the presence and characteristics of SGN-neural stem cells (NSCs) in mice as a function of age. Methods. The expression of Nestin and Ki67 was examined in sequentially dissected cochlear modiolar tissues from mice of different ages (from postnatal day to 24 weeks) and the sphere-forming populations from the SGNs were isolated and differentiated into different cell types. Results. There were significant decreases in Nestin and Ki67 double-positive mitotic progenitor cells in vivo with increasing mouse age. The SGNs formed spheres exhibiting self-renewing activity and multipotent capacity, which were seen in NSCs and were capable of differentiating into neuron and glial cell types. The SGN spheres derived from mice at an early age (postnatal day or 2 weeks) contained more mitotic stem cells than those from mice at a late age. Conclusion. Our findings showed the presence of self-renewing and proliferative subtypes of SGN-NSCs which might serve as a promising source for the regeneration of auditory neurons even in adult mice.

Temporal and Spatial Variations of Water Quality in the Cheonsu Bay of Yellow Sea, Korea (천수만 수질환경의 시·공간적 변동특성)

  • Park, Soung-Yun;Heo, Seung;Yu, Jun;Hwang, Un-Ki;Park, Jong-Su;Lee, Sung-Min;Kim, Chang-Mi
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.19 no.5
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    • pp.439-458
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    • 2013
  • Temporal and spatial variations of water quality were investigated in the Cheonsu Bay of Yellow Sea, Korea from 2010 to 2011. Water samples were collected at 16 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO), Chlorophyll a and nutrients. Spatial distribution patterns of all survey items were not clear among stations but the bimonthly variations were distinct except the bottom water of the suspended solids. The trend analysis by principal component analysis (PCA) during 2 years revealed the significant variations in water quality in the study area. Spatial water qualities were discriminated into 3 clusters by PCA; station cluster in the surface water 1, 2~11, and 12~16, the bottom water 1, 2~7, and 8~16. Annual bimonthly water qualities were clearly discriminated into 3 clusters by PCA. But tend of cluster in the surface and bottom water was difference, period most of the research was low in nutrient. Ecology-based water quality criteria was a good level of grade II. Bimonthly results are shown as III grade(normal) at June and August, II grade(good) at October and December and I grade for February and April. Water quality was showed by the input of fresh water same as those of Kyoungin coastal area, Asan coastal area, Gunsan coastal and Mokpo coastal area in the Cheonsu.

Long-term Variation and Characteristics of Water Quality in the Gunsan Coastal Areas of Yellow Sea, Korea (군산연안 수질환경의 특성과 장기변동)

  • Park, Soung-Yun;Choi, Ok-In;Kwon, Jung-No;Jeon, Kyeong-Am;Jo, Jo-Yeong;Kim, Hyung-Chul;Kim, Pyoung-Joong;Park, Jong-Soo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.15 no.4
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    • pp.297-313
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    • 2009
  • Long-term trends and distribution patterns of water quality were investigated in the Gunsan coastal areas of Yellow Sea, Korea from 1972 to 2006. Water samples were collected at 6 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids(SS), chemical oxygen demand(COD), dissolved oxygen(DO) and nutrients. Spatial distribution patterns of temperature, DO and SS were not clear among stations but the seasonal variations were distinct except COD and SS. The trend analysis by principal component analysis(PCA) during 24 years revealed the significant variations in water quality in the study area. Spatial water qualities were clearly classified into 3 clusters by PCA; station cluster 1, 2~4, and 5~6. Annual water qualities were clearly classified into 4 surface water clusters and 5 bottom water clusters by PCA. By this multi-variate analysis. The annual trends were summarized as follows; Salinity, pH and DO tended to increase since late 1970's, COD to increase since 1987, and SS to decrease and nutrients to increase in Gunsan coastal waters due to the input of fresh water from land same as in Kyoungin coastal area, Asan coastal area and Choensoo bay.

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The Change of the Depositional Environment on Dodaecheon River Basin during the Middle Holocene (Holocene 中期에 있어서 道垈川流域의 堆積 環境 變化)

  • Hwang, Sang-Ill;Yoon, Soon-Ock;Jo, Wha-Ryong
    • Journal of the Korean Geographical Society
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    • v.32 no.4
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    • pp.403-420
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    • 1997
  • Dodaecheon is a small river flowing into Asan Bay which is located in the middle part of the West Coast of the Korean Penninsula. We have investigated the change of depositional environment in Dodaecheon river basin during the middle Holocene. In the course of the research, the methods such as boring, radiocarbon dating, diatom and pollen analysis were employed. The Holocene deposits of the studied area are consisted of peat and gray silt layers, and contain many plooen and diatom fossils. Based on the results of diatom and pollen analysis, we conclude that the gray silt layers were sedimented owing to the transgression in the middle Holocene, and the peat layers by the regression or stabilzation of the sea level. The shoreline in the Post Glacial Age reached to the rivemouth of Dodaecheon at ca. 7,000 years before present(y. BP) and at that time the high tide sea-level(mean high water level of spring tide) rose to ca. 3m above present mean sea-level(m.a.s.l.). Since then to ca. 6,000y. BP, the high tide sea-level arrived to ca. 5m above present mean sea level further repeating minor transgressions and regressions. The peat layers of the coastal lowland of the West Coast were formed by the sea level fluctuations from 7,000 y. BP to 3,000 y. BP, and they were distributed 2 to 6 meters higher than the mean sea level of the present day. Most of them sedimented due to the high tide level are older and higher than those of the East Coast which were formed at the swale in the low tidal range environment.

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