• Journal of Life Science
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• v.29 no.1
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• pp.60-68
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• 2019

Limonium tetragonum, an edible halophyte that grows on salt marshes in Korea, is thought to possess various health benefits (e.g., antioxidant, antitumor, and hepatoprotective). In the present study, different solvent partitioned subfractions, water ($H_2O$), buthanol (n-BuOH), 85% aqueous methanol (85% aq. MeOH), and hexane (n-hexane), from crude extract of L. tetragonum were tested for their ability to prevent adipogenesis in differentiating 3T3-L1 preadipocytes. The treatment of differentiating 3T3-L1 preadipocytes with L. tetragonum subfractions (LTFs) resulted in suppressed adipogenesis and reduced expression of adipogenesis-related transcription factors such as peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), CCAATT/enhancer-binding protein alpha ($C/EBP{\alpha}$), and sterol regulatory element-binding protein 1c (SREBP-1c) at both mRNA and protein levels. In addition, the LTF treatment notably decreased the levels of phosphorylated p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) of the mitogen-activated protein kinase (MAPK) pathway in association with $PPAR{\gamma}$-linked adipogenesis. Among all the tested LTFs, $H_2O$ and n-hexane were the most effective in lowering lipid accumulation and regulating the adipocyte differentiation via $PPAR{\gamma}$ pathway. Taken together, the results indicated that the $H_2O$ and n-hexane LTFs contain bioactive compounds that may exhibit significant antiadipogenesis activity by downregulation of the $PPAR{\gamma}$ pathway and inactivation of the MAPK signal pathway in 3T3-L1 preadipocytes.

• Journal of fish pathology
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• v.18 no.1
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• pp.19-28
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• 2005

Scuticociliatosis has badly settled one of most damaging diseases during the seedling production process of olive flounder. Paralichthys olivaceus in Korea. We isolated a new type of Scuticociliate from flounder. The parasite metamorphoses to ciliate and cyst phases with each other by environmental changes and survive for a relatively long span. The ciliate was measured average 41.8 ${\mu}m$ in length and 21.0 ${\mu}m$ in width, and cyst was 17.0 ${\mu}m$ and 13.5 ${\mu}m$, respectively. Nutritional condition was determined as a major parameter of metamorphosing between ciliate and cyst stages. The ciliate transforms to a cyst stage because of food shortage, and the cyst returns to a ciliate stage with a favorite environmental condition and shows active growth and reproduction. The ciliate multiplied at the maximal density of $2.9 {\times} 10^5 {m\ell}^{-1}$cells in vitro cultivation at $15 ^{\circ}C$temperature using MS BHI medium and bacterial food sources. The ciliate could be proliferated at a 2.5 to $30 ^ \circ}C$ temperature range, pH 6 to 9, and 1 to 55 ppt salinity. Particularly, it survived over one week at $0 ^{\circ}C$temperature showing a high resistance against unfavorable environmental conditions. And the cyst survived for 320 days in the condition of $5 ^{\circ}C$with no feeding, but its survival period was markedly shortened in higher temperature conditions. The chemotherapeutants (formalin and hydrogen peroxide) were clarified as effective chemicals against the ciliate during in vitro trials, but the effect of therapeutants differed in proportion, depending upon the density and the bathing time of chemical compounds.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.45-58
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• 2012

For the development of reference values and evaluation of water quality in various environmental conditions, we divided the coastal region around Korean peninsular into 5 distinctive ecological regions based on the influence of surface current, depth, tidal range, turbidity, and climate condition. We used national marine environment monitoring data collected by National Fisheries Research & Development Institute(NFRDI) from 2000-2009. For the reference values, we used maximum seasonal mean from 2000 to 2007 for DIN, DIP, and chlorophyll-a and minimum seasonal mean for secchi depth measured at stations without the influence of river runoff in each ecological regions. For the reference value of bottom dissolved oxygen saturation, we used minimum mean value of 90% calculated from minimal riverine influence stations of whole regions. We calculated enrichment score for each assessment criteria. The enrichment score of DIN, DIP, and Chlorophyll-a was 1 (=< reference value), 2 (< 110% of reference value), 3 (< 125% of reference value), 4 (< 150% of reference value), and 5 (> 150% of reference value). The enrichment score of DO saturation and Secchi depth was 1 (> reference value), 2 (> 90% of reference value), 3 (>75 % of reference value), 4 (> 50% of reference value), and 5 (< 50% of reference value). We calculated water quality index using weighted linear combination of five enrichment score for the comparison of whole regions. From the water quality index distribution calculated from all stations between 2000 and 2007 period, we classified into 5 grade based on the standard deviation calculated from total water quality index. We assigned grade very good(I), good(II), moderate(III), bad(IV), and very bad(V) when the water quality index was less than 23, minimum + 1 sd, +2 sd, +3 sd, and grater than minium+ 3 sd, respectively.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.327-336
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• 2011

Temporal and spatial variations of primary productivity were investigated in the estuary of Youngsan River and Mokpo coastal areas in 2009. After heavy rain, concentrations of ammonium, phosphate, and silicate increased at six stations in August. The torrential rainfall may cause an increase in nutrient concentrations during summer. There is no limitation of nutrients (except for February at the mid-Youngsan estuarine region YS2) but a potential phosphate limitation was apparent at all stations. Silicate depletion was observed at YS2 in February due to a massive diatom bloom. The trophic status of the Youngsan estuary and Mokpo coastal areas were inferred from an assessment of the primary productivity. In February and May, YS1 (upper Youngsan estuary site) and YS2, YS3 (near the Youngsan river estuary barrage), MP1 (upper Mokpo coastal region site) were appropriately assigned to the mesotrophic category. MP2 (mid-Mokpo coastal region site) and MP3 (outer site of Mokpo coastal region) were assigned to the oligotrophic category. All stations were classified to the oligotrophic status in November. In August, after heavy rain, Youngsan estuary stations maintained mesotrophic status. On the other hand, MP1 and MP2 were classified in the eutrophic category and MP3 to mesotrophic status. In particular, primary productivities of MP1 and MP2 were 9 and 7 times higher respectively than the standard of eutrophic status ($1,000-mgC\;m^{-2}d^{-1}$). These results suggest that a massive freshwater discharge from the Youngsan River estuary should be considered a main factor in the occurrence of phytoplankton bloom in Mokpo coastal areas during summer. Seasonal variations of primary productivity are closely related with depth-integrated Chl. a.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.342-347
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• 2004

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.

• Journal of the Korean Chemical Society
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• v.40 no.7
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• pp.474-482
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• 1996

Two crystal structures of the vacuum dehydrated $Ag^+$-exchanged zeolite X have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1)$^{\circ}C$ (a=24.922(1)${\AA}$ and a=24.901(1)${\AA}$, respectively). Each crystal was ion exchanged in flowing streams of aqueous $AgNO_3$ for three days. The first crystal was dehydrated at 300$^{\circ}C$ and $2{\times}10^{-6$torr for two days. The second crystal was similarly dehydrated at 350$^{\circ}C$. Their structures were refined to the final error indices, $R_1=0.095\;and\;R_2=0.092$ with 227 reflections, and $R_1=0.096\;and\;R_2=0.087$ with 334 reflections, respectively, for which I > 3${\sigma}$(I). In the first crystal, Ag species are found at five different crystallographic sites: sixteen $Ag^+$ ions fill the site I, the center of the double 6-ring, thirty-two Ag0 atoms fill the I' site in the sodalite cavities opposite double six-rings, seventeen $Ag^+$ ions lie at the 32-fold site II' inside the sodalite cavity at the single six-oxygen ring in the supercage, fifteen Ag+ ions lie at the 32-fold site II, in the supercage, and the remaining twelve $Ag^+$ ions lie at site III' in the supercage at a little off two-fold axes. In the second crystal, all Ag species are located similarly as crystal 1; 16 at site I, 28 at site I', 16 at site II, 16 at site II', 6 at site III and 6 at site III'. Total 88 silver species were found per unit cell. The remaining four Ag atoms were migrated out of the zeolite framework to form small silver crystallites on the surface of the zeolite single crystal. In the first structure, the numbers of Ag atoms per unit cell are approximately 32.0 and these may form tetrahedral $Ag_4$ clusters at the centers of the sodalite cavities. The probable four-atom cluster is stabilized by coordination to two $Ag^+$ ions. The Ag-Ag distance in the cluster, ca. 3.05 ${\AA}$, is a little longer than 2.89 ${\AA}$, Ag-Ag distance in silver metal. At least two six-ring $Ag^+$ ions on sodalite cavity (site II') must necessarily approach this cluster and this cluster may be viewed as a distorted octahedral silver cluster, (Ag6)2+.

• Korean Journal of Remote Sensing
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• v.40 no.4
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• pp.387-396
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• 2024

Most very high-resolution (VHR) satellite images provide rational polynomial coefficients (RPC) data to facilitate the transformation between ground coordinates and image coordinates. However, initial RPC often contains geometric errors, necessitating correction through matching with ground control points (GCPs). A GCP chip is a small image patch extracted from an orthorectified image together with height information of the center point, which can be directly used for geometric correction. Many studies have focused on area-based matching methods to accurately align GCP chips with VHR satellite images. In cases with seasonal differences or changed areas, edge-based algorithms are often used for matching due to the difficulty of relying solely on pixel values. However, traditional edge extraction algorithms,such as canny edge detectors, require appropriate threshold settings tailored to the spectral characteristics of satellite images. Therefore, this study utilizes deep learning-based edge information that is insensitive to the regional characteristics of satellite images for matching. Specifically,we use a pretrained pixel difference network (PiDiNet) to generate the edge maps for both satellite images and GCP chips. These edge maps are then used as input for normalized cross-correlation (NCC) and relative edge cross-correlation (RECC) to identify the peak points with the highest correlation between the two edge maps. To remove mismatched pairs and thus obtain the bias-compensated RPC, we iteratively apply the data snooping. Finally, we compare the results qualitatively and quantitatively with those obtained from traditional NCC and RECC methods. The PiDiNet network approach achieved high matching accuracy with root mean square error (RMSE) values ranging from 0.3 to 0.9 pixels. However, the PiDiNet-generated edges were thicker compared to those from the canny method, leading to slightly lower registration accuracy in some images. Nevertheless, PiDiNet consistently produced characteristic edge information, allowing for successful matching even in challenging regions. This study demonstrates that improving the robustness of edge-based registration methods can facilitate effective registration across diverse regions.

• Korean Journal of Remote Sensing
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• v.36 no.5_2
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• pp.867-879
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• 2020

As the era of space technology utilization is approaching, the launch of CAS (Compact Advanced Satellite) 500-1/2 satellites is scheduled during 2021 for acquisition of high-resolution images. Accordingly, the increase of image usability and processing efficiency has been emphasized as key design concepts of the CAS 500-1/2 ground station. In this regard, "CAS 500-1/2 Image Acquisition and Utilization Technology Development" project has been carried out to develop core technologies and processing systems for CAS 500-1/2 data collecting, processing, managing and distributing. In this paper, we introduce the results of the above project. We developed an operation system to generate precision images automatically with GCP (Ground Control Point) chip DB (Database) and DEM (Digital Elevation Model) DB over the entire Korean peninsula. We also developed the system to produce ortho-rectified images indexed to 1:5,000 map grids, and hence set a foundation for ARD (Analysis Ready Data)system. In addition, we linked various application software to the operation system and systematically produce mosaic images, DSM (Digital Surface Model)/DTM (Digital Terrain Model), spatial feature thematic map, and change detection thematic map. The major contribution of the developed system and technologies includes that precision images are to be automatically generated using GCP chip DB for the first time in Korea and the various utilization product technologies incorporated into the operation system of a satellite ground station. The developed operation system has been installed on Korea Land Observation Satellite Information Center of the NGII (National Geographic Information Institute). We expect the system to contribute greatly to the center's work and provide a standard for future ground station systems of earth observation satellites.

• Korean Journal of Ichthyology
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• v.13 no.2
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• pp.143-157
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• 2001

To determine seasonal fluctuations in abundance and species composition of the fishes, samples were collected by bottom trawl off Kohung Penisula from February to December 1999. A total of 7,197 fishes were sampled and identified into 123 species, 54 families, 13 orders and 2 classes. Of the 13 orders, Perciformes, Scorpaniformes, Pleuronectiformes and Tetraodontiformes accounted for approximately 82.9% of the total. Gobiid fishes were dominant, representing 13 species. Leiognathus nuchalis, Konosirus punctatus, Engraulis japonicus, Ilisha elongata, Trichiurus japonicus, Argyrosomus argentatus, Ditrema temmincki, Takifugu niphobles, Hexagrammos otakii and Lateolabrax japonicus accounted for 71.4% of the number of individuals. Mugil cephalus, Sebastes schlegeli, Lateolabrax japonicus, Konosirus punctatus, Hexagrammos otakii, Conger myriaster, Liparis tanakai, Seriola quinqueradiata, Trichiurus japonicus, Sebastiscus marmoratus and Limanda yokohamae accounted for 50.7% of the total biomass. The number of species showed a seasonal variation, higher in spring, summer and autumn than in winter. The Largest numbers of individuals and greater biomass were observed in August. The economic fishes of this area were Konosirus punctatus, Engraulis japonicus, Mugil cephalus, Sebastes inermis, Sebastes schlegeli, Sebastes oblongus, Sebastiscus marmoratus, Platycephalus indicus, Hexagrammos agrammus, Hexagrammos otakii, Lateolabrax japonicus, Epinephelus akaara, Epinephelus septemfasciatus, Seriola quinqueradiata, Pagrus major, Acanthopagrus schlegeli, Argyrosomus argentatus, Oplegnathus fasciatus, Trichiurus japonicus, Pampus echinogaster, Paralichthys olivaceus, Kareius bicoloratus, Limanda yokohamae and Takifugu porphyreus.

• Journal of Aquaculture
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• v.18 no.4
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• pp.236-244
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• 2005

Experiments were performed to investigate the effects of the different anesthetic MS-222 and lidocaine-HCl doses on the blood physiological responses, on the time required for anesthesia and recovery, and on the survival rates of black rockfish (Sebastes schlegeli). Plasma cortisol was its highest levels (96.1$\pm$12.1 ng/ml) at 6 hours after the administration of 300 ppm of MS-222, and in all groups, plasma cortisol levels were higher than the initial levels during the anesthetic experiment. Fish receiving lidocaine-HCl also exhibited higher than initial plasma cortisol levels at almost experimental intervals. The middle size fish exhibited the highest glucose level (143.3$\pm$14.5 mg/dl) at 50 ppm of anesthesia after 1 hour, and every level was significantly higher than the initial level for at least 12 hours. Glucose levels in fish to which lidocaine-HCl was administered were comparable to the levels seen in conjunction with MS-222 treatment. In fish anesthetized with MS-222, K+ levels in the small size fish were significantly elevated after 1 hour, while Na+ levels did not change in any of the groups throughout the experiment. Anesthetic time was significantly attenuated with increases in the concentrations of MS-222 and lidocaine-HCl. We also noted a correlation between anesthetic time and fish size, in that larger fish took a longer time, followed by the middle size and then the small size fish. The all fish size groups showed above $95\%$ survival rates at every experimental concentration in MS-222 and 300-400 ppm in lidocaine-HCl. The results may indicate that 100-200 ppm MS-222 and 400 ppm lidocaine-HCl are the most effective doses as sedatives for the black rockfish and these doses could be used as the suitable anesthetics doses.