• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.121-129
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• 2014

Marine algal flora and community structure were seasonally investigated at four sites in the vicinity of the Igidae on the southern east coast of Korea from May 2010 to February 2011. A total of 66 species including 9 of Chlorophyta, 14 of Phaeophyta, 43 of Rhodophyta were found during the survey period. Among these species, 16 species were found throughout the year. Seasonal mean biomass in wet weight was 123.6 (spring), 2,061.6 (summer), 412.0 (autumn), 678.9 (winter) $g{\cdot}m^{-2}$. Maximum biomass was recorded in summer($2,061.6g{\cdot}m^{-2}$), and minimum was recorded in spring($123.6g{\cdot}m^{-2}$). Spatial maximum and minimum species number were recorded at station 3 and 4(50 species) and at station 1(47 species). At station 1, 2 directly exposure on Yongho and Daeyeon cheon (stream) run off, and discharge from Nambu sewage treatment plants near coastal area, species diversity was relatively low and dominant species were similar throughout four seasons. The R/P, C/P and (R+C)/P value reflecting flora characteristics were 3.07, 0.64 and 3.71, respectively. The flora investigated could be classified into six functional groups such as coarsely branch form 39.39 %, sheet form 30.30 %, thick leather form 13.64 %, filamentous form 12.12 %, crustose form 3.03% and jointed calcareous form 1.52 % during survey period. The number of marine algae species in Igidea were 96 species at 1996 to 1997 and 66 species at 2010 to 2011, respectively. The change of seaweed species is due to the pollution loaded from sewage treatment plant and stream. We thus recommend that the positive maintenance control method like sewage treatment, for the protection of seaweed bed should be proceeded to near coastal area.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.21-22
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• 2019

Melanin is a mixture of pigmented biopolymers synthesized by epidermal melanocytes that determine the skin, eye, and hair colors. Melanocytes produce two different kinds of melanin, eumelanin (dark brown/black insoluble pigments found in dark skin and dark hair and pheomelanin (lighter red/yellow). The biological role of melanin is to prevent skin damage by ultraviolet (UV) radiation. However, the overproduction or deficiency of melanin synthesis could lead to serious dermatological problems, which include melasma, melanoderma, lentigo, and vitiligo. Therefore, regulating melanin production is important to prevent the pigmentation disorders. Myanmar has a rich in natural resources. However, the chemical constituents of these natural resources in Myanmar have not been fully investigated. In the effort to search for compounds with anti-melanin deposition activity from Myanmar natural resources, five plants were collected in Myanmar. Extracts of these collected five plants were tested for anti-melanin deposition activity against a mouse melanoma cell line (B16-F10) induced with ${\alpha}$-melanocyte-stimulating hormone (${\alpha}$-MSH) and 3-isobutyl-1-methylxanthine (IBMX), and their anti-melanin deposition activities were compared with the positive control, arbutin. Among the tested extracts, the CHCl3 extracts of the Premna serratifolia (syn: P. integrifolia) wood showed anti-melanin deposition activities with IC50 values of $81.3{\mu}g/mL$. Hence, this study aims to identify secondary metabolites with anti-melanin deposition activity from P. serratifolia wood of Myanmar. P. serratifolia belongs to the Verbenaceae family and is widely distributed in near western sea coast from South Asia to South East Asia, which include India, Malaysia, Vietnam, Cambodia, and Sri Lanka. People in Tanintharyi region located in the southern part of Myanmar utilize the P. serratifolia, Sperethusa crenulata, Naringi crenulata, and Limonia acidissima as Thanaka, traditional cosmetics in Myanmar. Thanaka is applied in the form of paste onto skins to make it smooth and clear, as well as to prevent wrinkles, skin aging, excessive facial oil, pimples, blackheads, and whiteheads. However, the chemical constituents responsible for their cosmetic properties are yet to be identified. Moreover, the chemical constituents of P. serratifolia was almost uncharacterized. Investigation of the P. serratifolia chemical constituents is thus an attractive endeavor to discover new anti-melanin deposition active compounds. The investigation of the chemical constituents of the active CHCl3 extract of P. serratifolia led to isolation of four new lignoids, premnan A (1), premnan B (2), taungtangyiol C (3), and 7,9-dihydroxydolichanthin B (4), together with premnan C (5) (assumed to be an artifact), one natural newlignoid,(3R,4S)-4-(1,3-benzodioxol-5-ylcarbonyl)-3-[(R)-1-(1,3-benzo dioxol-5-yl)-1-hydroxy methyl]tetrahydro-2-furanone (6), and five known compounds (7-11)1,2). The structures of all isolated compounds were determined on the basis of their spectroscopic data and by comparison with the reported literatures. The absolute configurations of 1-3 and 5 were also determined by optical rotation and circular dichroism (CD) data analyses1). The anti-melanin deposition activities of all the isolated compounds were evaluated against B16-F10 cell line. 7,9-Dihydroxydolichanthin B (4) and ($2{\alpha},3{\alpha}$)-olean-12-en-28-oic acid (11) showed strong anti-melanin deposition activities with IC50 values of 18.4 and $11.2{\mu}M$, respectively, without cytotoxicity2). On the other hand, compounds 1-3, 5, and 7 showed melanogenesis enhancing activities1). To better understand their anti-melanin deposition mechanism, the effects of 4 and 11 on tyrosinase activities were investigated. The assay indicated that compounds 4 and 11 did not inhibit tyrosinase. Furthermore, we also examined the mRNA expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). Compounds 4 and 11 down-regulated the expression of Tyr and Mitf mRNAs, respectively. Although the P. serratifolia wood has been used as traditional cosmetics in Myanmar for centuries, there are no scientific evidences to support its effectiveness as cosmetics. Investigation of the anti-melanin deposition activity of the chemical constituents of P. serratifolia thus provided insight into the effectiveness of the P. serratifolia wood as a cosmetic agent.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.3
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• pp.147-153
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• 2013

There exist various types of the WEC (Wave Energy Converter), and among them, the point absorber is the most popularly investigated type. However, it is difficult to find examples of systematically measured data analysis for the design of the point absorber type of power buoy in the world. The study investigates the wave load acting on the point absorber type resonance power buoy wave energy extraction system proposed by Kweon et al. (2010). This study analyzes the time series spectra with respect to the three-year wave data (2002.05.01~2005.03.29) measured using the pressure type wave gage at the seaside of north breakwater of Hupo harbor located in the east coast of the Korean peninsula. From the analysis results, it could be deduced that monthly wave period and wave height variations were apparent and that monthly wave powers were unevenly distributed annually. The average wave steepness of the usual wave was 0.01, lower than that of the wind wave range of 0.02-0.04. The mode of the average wave period has the value of 5.31 sec, while mode of the wave height of the applicable period has the value of 0.29 m. The occurrence probability of the peak period is a bi-modal type, with a mode value between 4.47 sec and 6.78 sec. The design wave period can be selected from the above four values of 0.01, 5.31, 4.47, 6.78. About 95% of measured wave heights are below 1 m. Through this study, it was found that a resonance power buoy system is necessary in coastal areas with low wave energy and that the optimal design for overcoming the uneven monthly distribution of wave power is a major task in the development of a WEF (Wave Energy Farm). Finding it impossible to express the average spectrum of the usual wave in terms of the standard spectrum equation, this study proposes a new spectrum equation with three parameters, with which basic data for the prediction of the power production using wave power buoy and the fatigue analysis of the system can be given.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.77-86
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• 2017

This study was conducted to analyze the relationship among climatic factors and radial growth of Pinus densiflora and Larix kaempferi in South Korea. To determine the climate-growth relationship, cluster analysis was applied to group surveyed regions by the climatical similarity, and a dendroclimatological model was developed to predict radial growth for each climate group under the RCP 4.5 and RCP 8.5 scenarios for greenhouse gases. The cluster analysis showed four climatic clusters (Cluster 1~4) from 10 regions for P. densiflora and L. kaempferi. The dendroclimatological model was developed through climatic variables and standardized residual chronology for each climatic cluster of P. densiflora and L. kaempferi. Four climatic variables were used in the models for P. densiflora ($R^2$ values between 0.38 to 0.58). Two to five climatic variables were used in the models for L. kaempferi ($R^2$ values between 0.31 to 0.43). The growth simulations with two RCP climate-change scenarios(RCP 4.5 and RCP 8.5) were used for growth prediction. The radial growth of the Cluster 4 of P. densiflora, the mountainous region at high elevation, tend to increase, while those of cluster 2 and 3 of P. densiflora, the region of the hightest average temperature, tends to decrease. The radial growth of the Cluster 1 of L. kaempferi the region of the lowest minimum temperature, while that of Cluster 2, the region of the highest average temperature, tends to decrease. The radial growth of Cluster 3 of L. kaempferi, the region in the east coast and Cluster 4, the region at high elevation, tends to hold steady. The results of this study are expected to provide valuable information necessary for predicting changes in radial growth of Pinus densiflora and Larix kaempferi caused by climate change.

• Weed & Turfgrass Science
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• v.6 no.1
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• pp.11-20
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• 2017

Ninety species belonging to 28 families of weeds were identified in Korean rice fields. They were divided by eight provinces and 19 agro-climatic zones to be used as basic data of weed control. Looking at the regional weed occurrence, there were 52 species of 20 families in Gyeonggi, 37 species of 17 families in Gangwon, 41 species of 15 families in Chungbuk, 21 species of 12 families in Chungnam, 24 species of 13 families in Jeonbuk, 54 species of 21 families in Chonnam, 36 species of 20 families in Gyeongbuk, and 32 species of 16 families in Gyeongnam province, respectively. The most dominant family was Poaceae followed by Cyperaceae and Asteraceae. Mostly dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea, Scirpus juncoides var. hotarui, Eleocharis kuroguwai, and Sagittaria sagittifolia subsp. leucopetala with slight differences among the provinces. Although there were some differences in 18 climate zones from Taebaek sub-highlands to the southern part of the East Coast (except for the Taebaek Highland), the dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea and Scirpus juncoides var. hotarui. The most dominant family was Cyperaceae followed by Poaceae and Asteraceae. The differences of weed occurrence between provinces and agro-climatic zones were largely influenced by various weather conditions rather than the provinces. The changes in cultivation mode and herbicide use might influence as well.

• The Korean Journal of Petroleum Geology
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• v.2 no.2 s.3
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• pp.59-70
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• 1994

The Cenozoic geological structures and the tectonic evolution of the southern Ulleung Basin were studied with seismic profiles and exploration well data. Basement structure of the Korea Strait is distinctly characterized by normal faults trending northeast to southwest. The normal faults of the basement are most likely related to the initial liking and extensional tectonics of Ulleung Basin. Tsushima fault along the west coast of Tsushima islands runs northeastward to the central Ulleung Basin. The Middle Miocene and older sequences in the Tsushima Strait show folds and faults mostly trending northeast to southwest. These folds and faults may be interpreted as a result of compressional tectonics. The Late Miocene to Qauternary sequences are not much deformed, but numerous faults mostly N-S trending are dominated in the Tsushima Strait. The Ulleung Basin was in intial rifting during Oligocene, and then active extension and subsidence from Early to early Middle Miocene. Therefore SW Japan separated from Korea Peninsula and drifted toward southeast, and Ulleung Basin was formed as a pull-apart basin under dextral transtensional tectonic regime. During rifting and extensional stage, Tsushima fault as a main tectonic line separating SW Japan block from the Korean Peninsula acted as a normal faulting with right-lateral strike-slip motion as SW Japan drifted southeastward. During middle Middle Miocene to early Late Miocene, the opening of Ulleung basin stopped and uplifted due to compressional tectonics. The southwest Japan block converging on the Korean Peninsula caused compressional stress to the southern margin of Ulleung Basin, resulting in strong deformation under sinistral transpressional tectonic regime. Tsushima fault acted as thrust fault with left-lateral strike-slip motion. From middle Late Miocene to Quaternary, the southern margin of Ulleung Basin has been controlled by compressional motion. Thus the Tsushima fault still appears to be an active thrust fault by compressional tectonic regime.

• Journal of Korea Water Resources Association
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• v.57 no.6
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• pp.421-435
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• 2024

In April 2023, a wildfire broke out in Gangneung located in the east coast region due to the influence of the Yanggang-local wind. In this study, GIS-based RUSLE(Revised Universal Soil Loss Equation) and SEMMA (Soil Erosion Model for Mountain Areas) were used to evaluate the erosion rate due to vegetation recovery in a small watershed of the Gangneung WUI(Wildland-Urban Interface) fire. The small watershed of WUI fire has a low altitude range of 10-30 m and the average slope of 10.0±7.4° which corresponds to a gentle slope. The soil texture was loamy sand with a high organic content and the deep soil depth. As herbaceous layer regenerated profusely in the gully after the wildfire, the NDVI (Normalized Difference Vegetation Index) reached a maximum of 0.55. Simulation results of erosion rates showed that RUSLE ranged from 0.07-94.9 t/ha/storm and SEMMA ranged from 0.24-83.6 t/ha/storm. RUSLE overestimated the average erosion rate by 1.19-1.48 times compared to SEMMA. The erosion rates were estimated to be high in the middle slope where burned pine trees were widely distributed and the slope was steep and to be relatively low in the hollow below the gully where herbaceous layer recovers rapidly. SEMMA showed a rapid increase in erosion sensitivity under at certain vegetation covers with NDVI below 0.25 (Ic = 0.35) on post-fire hillslopes. Gentle slopes with high organic content and rapid recovery of natural vegetation had relatively low erosion rate compared to steep slopes. As subsequent infrastructure and human damages due to sediment disaster by heavy rain is anticipated in WUI fire areas, the research results may be used as basic data for targeted management and decision making on the implementation of emergency treatment after the wildfire.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.262-269
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• 2012

We investigated the concentration levels and evaluated the distributions of 17 polychlorinated dibenzo-p-dioxins and furans(PCDD/Fs), 12 dioxin-like polychlorinated biphenyls(DLPCBs) and 24 polybrominated diphenyl ethers (PBDEs) in sediment and organism from various culturing grounds in Korean coast. The levels of PCDD/Fs, DLPCBs, and PBDEs in sediment samples ranged from 0.03 to 2.9(Mean${\pm}$SD, $1.2{\pm}0.89$) pg $WHO_{2005}$-TEQ $g^{-1}$ dry weight(dw), ND(not detected) to 1.1($0.09{\pm}0.19$) pg $WHO_{2005}$-TEQ $g^{-1}$ dw, and ND to 16.6($2.96{\pm}3.53$) ng $g^{-1}$ dw, respectively. Also, the levels of PCDD/Fs, DLPCBs, and PBDEs in culturing organisms ranged from ND to 0.24($0.07{\pm}0.06$) pg $WHO_{2005}$-TEQ $g^{-1}$ wet weight(ww), ND to 0.11($0.04{\pm}0.04$) pg $WHO_{2005}$-TEQ $g^{-1}$ ww, and 0.05 to 0.29($0.13{\pm}0.06$) ng $g^{-1}$ ww, respectively. The levels of total dioxins(PCDD/Fs+DLPCBs) and PBDEs in sediments from East and South sea were four to seven times higher than those from West sea. PCDD/Fs had dominant contribution(mean, 94%) for TEQ concentration in sediment, whereas relatively higher contribution of DLPCBs(33%) were shown in culturing organism than sediment. BDE209 was a dominant congener in both matrix. The concentrations of PCDD/Fs, DLPCBs and PBDEs were in decreasing trends in Korea coasts compared to previous results.

• Korean Journal of Veterinary Research
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• v.22 no.2
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• pp.175-185
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• 1982

Since bovine lymphosarcoma causes considerable economic loss to the dairy industry, seroepidemiological survey on bovine leucosis virus (BLV) was carried out for the dairy herds throughout the country to observe the epidemiological situation of the disease by using immunodiffusion test. Attempts were simultaneously made to detect bovine leucosis virus in the lymphocytes from BLV antibody-positive cattle by means of fluorescent antibody techniques, syncytium assay and electron microscopy. In immunodiffusion test for BLV antibody in 2003 heads of dairy cattle selected randomly from 164 herds, the prevalence of positive reactors by regions were 37.8% in Central, 27.2% in Honam (Southwest), 28.0% in Youngnam (Southeast) and 25.2% in Youngdong (East coast)and averaging 29.7%. By provinces, Chungcheong appeared the highest prevalence of BLV antibody carriers (41.8%), while Jeonbug revealed the lowest incidence rate (24.4%). When the results of serological studies were analyzed by age groups and the sizes of herds, the number of reactors increased gradually with the advance in the age of cattle and the herd size. The highest rate of BLV carriers was found in the ages between 6 and 8 years, and in the size of herds with 20 to 50 heads. One hundred and seventeen breeding bulls from the central regions were tested for BLV antibody. Four out of 70 bulls (5.7%) of Korean cattle and 14 out of 39 bulls (35.9%) of Holstein were reactive for BLV antigens. Of 164 dairy herds examined, 17 herds (10.4%) have no BLV antibody-positive cattle, while 42 herds (25.6%) were included in the range of 20 to 40% of the positive rate and 10 herds (6.1%) in the range of over 80% of the rate. When the lymphocytes from the BLV antibody carrying cattle were cultured in the presence of phytohemagglutinin and stained with FITC-conjugated sheep anti-BLV serum, 8 out of 11 cases (72.7%) of BLV positive cattle revealed specific fluorescence for BLV in the lymphocytes. In syncytium assay of the peripheral lymphocytes of the cattle, 5 out of 7 (71.4%) lymphocytes from BLV antibody carriers induced syncytia in the indicators of bovine embryonic splenic cells. The cultured lymphocytes were examined with an electron microscope to detect the BLV particles. Two out of 6 specimens (33.3%) from the reactors showed the typical type C virus with the size of 90 to 110 nm around microvilli and in intracytoplasmic vacuoles.

• Journal of the Korean association of regional geographers
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• v.4 no.2
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• pp.151-164
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• 1998

I analyzed the correlation between El-Nino phenomenon and our country's temperature and precipitation laying the stress on the anomaly, and the result of this analysis is as follows: (1) The extraction of the occurrences of El-Nino at the place of sea surface around Nino.3 which was known as the sea area under observation for El-Nino reveals that there are 9 years (1969, 1970, 1973, 1977, 1987, 1992, 1995, 1998) when the temperature anomaly in January is more than 1.0 during the period of research years ($1969{\sim}1998$). (2) The tendency of change of sea surface temperature around Nino.3 and that of our country are about the same, but the anomaly of Pusan and Inchon was much greater than that of Jangki in the East Coast. (3) The anomaly of sea surface temperature around Nino.3 and that of the ground temperature showed the similar changing tendency, the temperature of our country has something to do with that of sea surface as the correlation of ground temperature with the temperature of sea surface showed 0.31. Anomaly warm winter has something to do with El-Nino because the temperature of our country was high when El-Nino phenomenon appeared. (4) As for the precipitation, we can see that it has generally increased after 1989 when the phenomenon of warm climate was intense than before that year. But as we study the change of anomaly, the precipitation has less correlation in comparison with the ground temperature. The precipitation in 1973, 1983 and 1987 which were El-Nino years was correlated with El-Nino. While the change of sea surface temperature has showed a tendency of plus(+)increase since 1990, the precipitation has showed a tendency of minus (-)decrease. Therefore it seems that the temperature of sea surface has little correlation with the amount of rainfall.