• Journal of The Geomorphological Association of Korea
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• v.26 no.4
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• pp.33-45
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• 2019

The shore platforms at Dok-do could be an important and clear indicator showing dimensional reduction of Dok-do. Especially flat type shore platforms are distributed in the southern coast of Dok-do island, composed of weak rocks against erosional resistance like interbedded lapilli tuff and massive tuff breccia. The distribution of shore platform is partially related to the wind direction at Dok-do island. The primary SW- and secondary SE winds are representative among wind directions at Dok-do, maintaining from spring to the autumn. Therefore, wide shore platforms could be developed by waves approaching from SW and SE directions in the southern coast of Dok-do. The sea stacks like Gunham-rock, Neopdeok-rock, Keungaje-rock and Jakeungaje-rock on the western coast are also considered to be formed by wave erosion from the SE direction. The shore platforms in the southern coast of Dok-do island were developed since ca. 7,000 yr. BP, when sea level raised almost to the present level. The average extension speed of shore platform was calculated to 4.0mm/y, because the broadest shore platform with the width ca. 28m was extended for ca. 7,000 years. The width's dimension of shore platform at Dok-do reflects a slow extension rate in the present, although erosional process will be faster with the sea level rise in the future.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1508-1518
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• 2021

Hsa_circ_0001947 is associated with multiple cancers, but its function in non-small cell lung cancer (NSCLC) is ambiguous and needs further research. The targeting relationship among circ_0001947, miR-661, and downstream of tyrosine kinase 7 (DOK7) was predicted by database and further verified by dual-luciferase reporter assay, while their expressions in cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). After transfection, cell biological behaviors and expressions of miRNAs, miR-661 and DOK7 were determined by cell function experiments and qRT-PCR, respectively. Circ_0001947 was low-expressed in NSCLC tissues and cells. Circ_0001947 knockdown intensified cell viability and proliferation, induced cell cycle arrest at S phase, suppressed apoptosis and evidently enhanced miR-510, miR-587, miR-661 and miR-942 levels, while circ_0001947 overexpression did the opposite. MiR-661 was a target gene of circ_0001947 that participated in the regulation of circ_0001947 on cell biological behaviors. Furthermore, DOK7, the target gene of miR-661, partly participated in the regulation of miR-661 on cell viability. Hsa_circ_0001947 acts as a sponge of miR-661 to repress NSCLC development by elevating the expression of DOK7.

• Biomedical Science Letters
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• v.26 no.3
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• pp.238-243
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• 2020

Tuberculosis is a global public health problem and manifests itself as a difference in the genetic susceptibility of the host, along with the properties of Mycobacterium tuberculosis (MTB). The single nucleotide polymorphisms (SNPs) and candidate genes proposed in the Genome-wide association study (GWAS) on tuberculosis in a recently published Chinese population were reported. In this study, we investigated whether the genetic polymorphism of candidate genes related to tuberculosis is reproduced when targeting Koreans. The CLCN6 (rs12404124, rs198391, rs535107), DOK7 (rs1203104, rs1203103) and HLA-DRA (rs1051336) gene polymorphisms showed statistically significant results. In addition, it was also found whether it acts as an expression quantitative trait loci (eQTL) that can influence gene expression. This study confirmed that the genetic polymorphism of the three genes (CLCN6, DOK7, HLA-DRA) affects the development of tuberculosis and will help to understand the genetic specificity of tuberculosis and the interaction between pathogens and hosts.

• The Journal of the Petrological Society of Korea
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• v.15 no.2 s.44
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• pp.72-80
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• 2006

We report new K-Ar ages of volcanic rocks from Ulleung-do and Dok-do islands located at the middle of the Korea Sea; $3.67{\pm}0.40\sim1.89{\pm}0.29$ Ma for the Dok-do and $8.07{\pm}0.39\sim0.51{\pm}0.07$ Ma for the Ulleung-do. Such ages reveal that igneous activities of both Dok-do and Ulleung-do extend longer than previously reported. It is likely that igneous activity of Ulleung-do started as early as $8.07{\pm}0.39$ Ma which is much older than age known currently, and latest eruption and intrusion of trachyte of Dok-do lasted until $1.89{\pm}0.29$ Ma, which overlaps previously reported igneous activity of Ulleung-do. However, it seems that the main volcano-building stage of Ulleung-do started after 2.7 Ma and igneous activities of Dok-do were finished mostly before then, which suggests that Dok-do was farmed before Ulleung-do in the respect of main stages of volcano-building. Such explanation agrees well with the hypothesis that southeastern seamounts, Dok-do and Ulleung-do were sequentially generated by relatively fixed hotspot.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.7
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• pp.534-541
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• 2002

Vibration and sound characteristics of King Song-Dok Bell are ivesigated. Natural frequencies. vibration modes and beat period of the bell are precisely measured. The effect of striking position and the position of nodal lines on the beat characteristics is examined. It is first found that the beat characteristics are quote different according to the position on the bell surface and clear beat is periodically generated on the circumference. It turns out that in King Song-Dok Bell, Dangjwa(the present striking position) is located at the position which makes a beat in the first vibration mode, as welt as it produces very clear beat In the second vibration mode.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.48-57
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• 2009

The characteristics of physico-chemical factors and the species compositions of phytoplankton were investigated to analyze the marine ecosystem at the depths during summer in the coast of Dokdo (stations DOK1$\sim$3). The mean values of conductivity (32 mS cm$^{-1}$), total dissolved solids (45 mg L$^{-1}$), salinity (35.5 psu), total suspended solids (39 mg L$^{-1}$) were the highest in DOK1. The biomass (chl-${\alpha}$) of phytoplankton was the highest in the surface of station DOK1 (3.1 ${\mu}g$ L$^{-1}$). By means of physico-chemical factors (salinity, turbidity, chl-${\alpha}$, T-N, T-P and Si), the coast of Dokdo was estimated to be more polluted than the previous results in 2000. A total of 72 species in Dokdo were composed of 54 species (76.1%) for Bacillariophyceae and 13 species (18.3%) for Dinophyceae, 3 species (4.2%) for Chrysophyceae and 1 species (1.4%) for Cyanophyceae. The standing crops of phytoplankton were the highest (8.5 $\times$ 10$^4$ cells L$^{-1}$) at 20 m of station DOK1, while they were the lowest (1.65 $\times$ 10$^4$ cells L$^{-1}$) at 30 m of station 1. The dominance index was maximum (0.73) at 10 m of station DOK1 and was minimum (0.4) at 30 m of station 1. The diversity index was the highest (2.92) in the surface of station 2, while it was the lowest at 20 m (1.58). The dominant species of phytoplankton were Chaetoceros affinis (3.3 $\times$ 10$^4$ cells L$^{-1}$) at 20 m, Climacosphenia moniligera (2.8 $\times$ 10$^4$ cells L$^{-1}$) at 40 m and Melosira juergensii (1.7 $\times$ 10$^4$ cells L$^{-1}$) at 10 m of station DOK1. At the surface of station DOK2, the dominant species were Bacillaria paxillifer and Richelia intracellularis (1.4 $\times$ 10$^4$ cells L$^{-1}$, respectively), while it was Paralia sulcata (1.6 $\times$ 10$^4$ cells L$^{-1}$) at the surface of station DOK3. The station DOKl, where affected by upwelling, turbulence and convection due to the East Korean Warm Current, was the most eutrophicated water body in three stations. The monitoring of marine ecosystem in the coast of Dokdo should be continued to show the alternatives for water and species conservation and to purify the eutrophicated water body due to artificial pollutants as well as physico-chemical factors by the global warming, the climatic change, CO$_2$ etc.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.421-428
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• 2017

The spatial distribution and abundance of fish species was estimate near Dok-do, East Sea of Korea by conducting midwater trawl survey with hydroacoustic method. Acoustic and midwater trawl data were collected onboard the R/V Tamgu 21 during 7-8 March 2016. Acoustic data were collected at the frequencies of 38 and 120 kHz and converted to nautical area scattering strength ($m^2/nmile^2$). Species are distributed mainly over an extent of 30-55 m, generally around southwest of Dok-do; the squid Watasenia scintillans was the dominant species found. The length-weight function and target strength of squid and other fishes were used to estimate the W. scintillans stock at 2499.1 tons and other fish at 43.8 tons during the winter season. The hydroacoustic method offers an approach for the determination of the biomass and vertical and spatial distributions of species aggregating near Dok-do, East Sea of Korea.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.216-221
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• 2010

This study shows an application of microbiologically induced carbonate precipitate for strength improvement and crack remediation of cement-sand mortar. Seven calcium carbonate-forming bacteria (CFB) were isolated from Dok-do and partially identified by DNA sequence analysis of the 16s rRNA gene. Crystal aggregates were apparent around the bacterial colonies grown on an agar medium. These strains showed strain specific $CaCO_3$ precipitation on urea-$CaCl_2$ medium. Among 7 isolates, Arthrobacter nicotinovorans KNUC601, Microbacterium resistens KNUC602, Agrobacterium tumefaciens KNUC603, Exiguobacterium acetylicum KNUC604, and Bacillus thuringiensis KNUC606 showed a repairing of artificial forced cracks in cement-sand mortar. Compressive strength of cement-sand mortar consolidated with Stenotrophomonas maltophilia KNUC605 was increased around 14.07% compared with that of negative control.

• ALGAE
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• v.22 no.3
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• pp.193-199
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• 2007

This study was carried out to investigate the charateristics of environmental factors and the species compositions of phytoplanktons and periphytons in order to analyze the marine ecosystem (DOK1-3) with freshwater (Mul) in the coast of Dokdo. Mean values of conductivity (TSD) (44.3 mS cm–1), total dissolved solids (30.9 mg L–1), salinity (31.8 psu), total suspended solids (39.2 mg L–1), and ash-free dry matter (AFDM) (8.8 mg L–1) were higher in DOK1- 3 than those in Mul (3.2 mS cm–1, 2.3 mg L–1, 1.9 psu, 2.8 mg L–1 and 2.8 mg L–1, espectively), while mean amounts of soluble reactive phosphorus (SRP) (7.5 μg P L–1) and soluble reactive silicon (SRS) (0.1 μg Si L–1) were significantly lower in DOK1-3 than those in Mul (117.3 μg P L–1 and 4,105 μg Si L–1, respectively). The phytoplanktons was a total of 59 species in Dokdo, which were composed of 1 species (1.7%) for Chrysophyceae, 43 species (72.9%) for Bacillariophyceae and 15 species (25.4%) for Dinophyceae. The biomass (Chl-a, phaeopigment and AFDM) of epilithic algae (ELA), epizooic algae (EZA) and epiphytic algae (EPA) were varied with the kinds of substrates (EPA > ELA > EZA) in the whole stations. Water environments was comparatively clean in the coast of Dokdo as comparing with those of the land. However, the monitoring of marine ecosystem in the Dokdo should be continued for species conservation according to the global warming by the climatic change.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.80-89
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• 2009

The rates of sediment oxygen demand(SOD) and denitrification(DNF) were measured using $^{15}N$ isotope pairing technique in intact sediment cores in the shelf of Dok Island. The SOD and DNF in the continental shelf of Dok Island were ranged from 1.04 to $9.08\;mmol\;m^{-2}\;d^{-1}$ and from 7.06 to $37.67\;{\mu}mol\;m^{-2}\;d^{-1}$, respectively. The SOD and DNF values in this study are higher than typical deep sea sediment. The SOD and DNF in this study were high in the high organic matter content sediment and high organic matter content was promotive of coupled nitrification-denitrification. Organic carbon contents in surface sediment ranged from 1.8 to 2.4%, which is higher than typical deep sea sediments. Therefore we conclude that the organic matter content in surface sediment is determined by the nature of the export production not the water depth in East sea sediment and the nature of the export production also determines remineralization processes such as SOD and DNF in East sea/Ulleung Basin sediment.