• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.1
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• pp.11-36
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• 2021

The solar annual (Sa) and semiannual (Ssa) tides account for much of the non-uniform annual and seasonal variability observed in sea levels. These non-equilibrium tides depend on atmospheric variations, forced by changes in the Sun's distance and declination, as well as on hydrographic conditions. Here we employ tidal harmonic analyses to calculate Sa and Ssa harmonic constants for 21 Korean coastal tidal stations (TS), operated by the Korea Hydrographic and Oceanographic Agency. We used 19 year-long (1999 to 2017) 1 hr-interval sea level records from each site, and used two conventional harmonic analysis (HA) programs (Task2K and UTide). The stability of Sa harmonic constants was estimated with respect to starting date and record length of the data, and we examined the spatial distribution of the calculated Sa and Ssa harmonic constants. HA was performed on Incheon TS (ITS) records using 369-day subsets; the first start date was January 1, 1999, the subsequent data subset starting 24 hours later, and so on up until the final start date was December 27, 2017. Variations in the Sa constants produced by the two HA packages had similar magnitudes and start date sensitivity. Results from the two HA packages had a large difference in phase lag (about 78°) but relatively small amplitude (<1 cm) difference. The phase lag difference occurred in large part since Task2K excludes the perihelion astronomical variable. Sensitivity of the ITS Sa constants to data record length (i.e., 1, 2, 3, 5, 9, and 19 years) was also tested to determine the data length needed to yield stable Sa results. HA results revealed that 5 to 9 year sea level records could estimate Sa harmonic constants with relatively small error, while the best results are produced using 19 year-long records. As noted earlier, Sa amplitudes vary with regional hydrographic and atmospheric conditions. Sa amplitudes at the twenty one TS ranged from 15.0 to 18.6 cm, 10.7 to 17.5 cm, and 10.5 to 13.0 cm, along the west coast, south coast including Jejudo, and east coast including Ulleungdo, respectively. Except at Ulleungdo, it was found that the Ssa constituent contributes to produce asymmetric seasonal sea level variation and it delays (hastens) the highest (lowest) sea levels. Comparisons between monthly mean, air-pressure adjusted, and steric sea level variations revealed that year-to-year and asymmetric seasonal variations in sea levels were largely produced by steric sea level variation and inverted barometer effect.

• Journal of Life Science
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• v.32 no.7
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• pp.510-522
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• 2022

In this study, to biosynthesize PHA with properties more similar to polypropylene, a Bacillus sp. EMK-5020 strain that biosynthesized poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was isolated from soil. Bacillus sp. EMK-5020 strain biosynthesized PHBV containing 1.3% 3-hydroxyvalerate (3HV) using reducing sugar contained in Makgeolli lees enzymatic hydrolysate (MLEH) as a single carbon source. As the amount of propionic acid, which was added as a second carbon source, increased, the content of 3HV also increased. PHBV containing up to 48.6% of 3HV was synthesized when 1.0 g/l of propionic acid was added. Based on these results, the strain was cultured for 72 hr in a 3 l fermenter using reducing sugar in MLEH (20 g/l) and propionic acid (1 g/l) as the main and secondary carbon sources, respectively. As a result, 6.4 g/l DCW and 50 wt% of PHBV (MLEH-PHBV) containing 8.9% 3HV were biosynthesized. Through gel permeation chromatography and thermogravimetric analysis, it was confirmed that the average molecular weight and the decomposition temperature of MLEH-PHBV were 152 kDa and 273℃, respectively. In conclusion, the Bacillus sp. EMK-5020 strain could biosynthesize PHBV containing various 3HV fractions when MLEH and propionic acid were used as carbon sources, and PHBV-MLEH containing 8.9% 3HV was confirmed to have higher thermal stability than standard PHBV (8% 3HV).

• Journal of Life Science
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• v.31 no.11
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• pp.1028-1036
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• 2021

Firefly luciferase (FLuc) can function as an efficient marker in the gene and viral therapies. Nonetheless, its clinical translation has been unaccomplished with the concerns on its exogenous nature and the similarity with human fatty acyl-CoA synthetase. In this study, we aimed to show safety of FLuc by conducting a set of preclinical experiments and a human use. Initially, FLuc permeability across the plasma membrane was investigated by delivering the FLuc-carrying viral vector, OTS-412, or the FLuc recombinant protein. After in vitro infection of OTS-412 into different cancer cell lines, FLuc activity was detected only in the cell lysates, but not in culture media. In addition, recombinant FLuc protein further showed the impermeability against the plasma membrane. Similar result was also observed in the in vivo experiment. After being injected into the VX2 tumor-bearing rabbit, the FLuc exclusively resided within the tumor tissue without being detected in the blood plasma or other organs. Human cancer cell lines originated from various organs were lysed and treated to the FLuc, and none of the human substrates was reactive against the FLuc. As a final step, FLuc recombinant protein was intravenously injected into a human. The luciferase was degraded with the half-life of 20 to 30 minutes in blood, and was untraceable from 1.5 hr after the injection. In addition, the blood plasma was nonresponsive against the fatty acids. Hematological analysis was also comparable between the pre- and post-injection. Altogether, our study collectively demonstrates the safety of the firefly luciferase.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.399-409
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• 2021

In order to utilize dolomite as a calcium/magnesium compound material, it was prepared highly reactive calcined dolomite(CaO·MgO) using a microwave kiln (950 ℃, 60 min). The experiment was performed according to the standard of the hydration test (ASTM C 110) and hydration reactivity was analyzed as medium reactivity (max 74.1 ℃, 5 min). Experiments were performed with calcined dolomite and salt (MgCl₂·6H₂O) (a) 1:1, (b) 1:1.5, and (c) 1:2 wt% based on the hydration reaction of calcined dolomite. The result of X-ray diffraction analysis confirmed that MgO of calcined dolomite increased to Mg(OH)₂ as the salt addition ratio increased. After the separating reaction, calcium was stirred at 80 ℃, 24 hr that produced CaCl₂ of white crystal. XRD results, it was confirmed calcium chloride hydrate (CaCl₂·(H₂O)x) and CaO of calcined dolomite and salt additional reaction was separated into CaCl₂. And it was synthesized with Ca(OH)₂ 99 wt% by NaOH adding reaction to the CaCl₂ solution, and the synthesized Ca(OH)₂ was manufactured CaO through the heat treatment process. In order to prepare calcium carbonate, CaCO₃ was synthesized by adding Na₂CO₃ to CaCl₂ solution, and the shape was analyzed in cubic form with a purity of 99 wt%.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.447-455
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• 2022

Fully dehydrated Tl₁₂-LTA (|Tl₁₂|[Si₁₂Al₁₂O₄₈]-LTA,Tl₁₂-A) was treated with 6.0×10³ Pa of ZrI₄ (g) at 623 K for 72 hr under anhydrous conditions. The crystal structure of product, |Zr_0.25I_1.5Tl₁₂|[Si₁₂Al₁₂O₄₈]-LTA, was determined by single-crystal crystallography using synchrotron X-radiation in the cubic space group Pm3m (a = 12.337(2) Å). It was refined using all data to the final error index (for the 712 unique reflections for which F_o> 4σ(F_o) R₁/wR₂= 0.055/0.189. In this structure, octahedral ZrI₆^2- ions center about 25% of the large cavities (Zr-I = 2.91(4) Å). Each coordinates to eight Tl⁺ ions and they are further bridged by Tl⁺ ions in the planes of 8-rings to form a cubic three-dimensional ZrI₆Tl₁₁⁹⁺ cationic cluster. About 1.5 Tl⁺ ions per unit cell moved to deeper side of sodalite cavity after reaction with ZrI₄(g). The remaining Tl⁺ ions occupy well-established cation positions near 6- and 8-rings.

• The Korea Journal of Herbology
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• v.27 no.6
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• pp.115-122
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• 2012

Objectives : This study evaluated activities and ingredient contents concerning extracts according to extraction solvents of Insampaedok-san (IS, Renshen bai du-san). Methods : The herbal constituents of IS were extracted with water and 70% ethanol at $100^{\circ}C$ for 2 hr. Using the HPLC system, the six ingredient contents of different solvent extracts of IS were analyzed. The nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$) production and proinflammatory cytokines were measured in RAW264.7 cells stimulated with lipopolysaccharide (LPS). The macrophage-derived chemokine (MDC/CCL22) and regulated on activation normal T-cell expression and secreted (RANTES/CCL5) production were measured in HaCaT and BEAS-2B cells stimulated tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interferon-${\gamma}$ (IFN-${\gamma}$). The activities of glycerol-3-phosphate dehydrogenase (GPDH) and leptin level were measured in 3T3-L1 cells. Results : The calibration curves showed good linearity ($r^2$=1.0000) for different concentration ranges. The contents of liquiritin, naringin, hesperidin, neohesperirin and glycyrrizin in 70% ethanol extracts of IS were relatively higher than that of water extract, however the content of ferulic acid in 70% ethanol and water extract of IS were similar. The extraction solvents of water and 70% ethanol were evaluated inhibitory effect on the production of NO, $PGE_2$, TNF-${\alpha}$ and IL-6 in RAW 264.7 cells. Their extractions were inhibitory effect on production of MDC/CCL22 and RANTES/CCL5 in HaCaT cell and BEAS-2B cell, respectively. In addition, evaluated reduced on GPDH activity and leptin level in 3T3-L1 preadipocyte cell. Conclusions : Our results suggest that IS extracts were inhibitory effects of disease such as inflammation, allergies and obesity.

• Journal of Life Science
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• v.32 no.2
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• pp.135-141
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• 2022

Thymosin β-4 (TB4) is a small peptide composed of 43 amino acids. To obtain sufficient biologically active mouse TB4 economically, we cloned and overexpressed this gene in an Escherichia coli system. With the isopropyl β-D-1-thiogalactopyranoside induction of the E. coli transformant, TB4 fusion protein with intein- and chitin-binding domain was successfully expressed in the soluble fraction within the E. coli cell. The TB4-intein - chitin-binding domain fusion protein was purified from the soluble fraction of E. coli cell lysate. The affinity chromatography with chitin beads and dithiothreitol-mediated intein self-cleavage reaction releases the TB4 peptide into the stripping solution. Sodium dodecyl sulphate - polyacrylamide gel electrophoresis and Western blot analyses were used to confirm that the recombinant TB4 peptide was produced with the expected size of 5 kDa. We found that the recombinant TB4 stimulated cell migration in the transwell plate chamber assay. After 18 hr of the treatment of the recombinant TB4 with 1 ng/ml concentration, the migration of the HT1080 cell was increased by 20% compared with that of the chemically synthesized TB4. The recombinant TB4 was also observed to promote the healing of a wound area in C57BL/6 mice by as high as 35% compared with that of the chemically synthesized TB4. These results suggest that the recombinant TB4 has better biological activity for cell migration and wound healing than that of the chemically synthesized TB4 peptide.

• Elastomers and Composites
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• v.22 no.3
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• pp.204-212
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• 1987

The purpose of this study is to investigate the reinforced effect between MGF treated silane coupling agents and rubber matrix under the configuration chemical bonds, also the effect of triazine thiol compounds. For this study, vulcanizates were prepared with fifteen different compounding formulas. Their vulcanization characteristics, physical properties were examined by means of the ODR(Oscillating Dist Rheometer), the tensile tester, the benzene swelling test. The results of this study obtained are as follows: 1. In the ODR test, the MA vulcanizate was the fastest one in terms of having reached to optimum cure time($t_{90}$) and, with the same formula, when MGF vulcanizates, the shortest optimum cure times has appeared. 2. The SA, SC vulcanizates were the best the other in the physical properties such as 100%modulus, 200%modulus, 300%modulus, tensile strength. The SB vulcanizate, with higher density of crosslinking than other vulcanizates. The vulcanizates, which were filled with MGF treated with silane coupling agents we were the higher density of crosslinking than vulcanizates filled with MGF only. 3. In aging properties, the silica vulcanizates appeared to be better than the other vulcanizates. The aging Properties of treated MGF vulcanizates were similar to the silica vulcanizates. The(CR+APS+silica) and(CR+APS+MCF) were easily crosslinked by exposure to the air, and the physical properties have been improved.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.79-88
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• 2008

Recently, the high speed railway comes into the spotlight as the important and convenient traffic infrastructure. In Korea, Kyung-Bu high speed train service began in bout 400 km section in 2004, and the Ho-Nam high speed railway will be constructed by 2017. The high speed train will run with a design maximum speed of 300-350 km/hr. Since the trains are operated at high speed, the differential settlement of subgrade under the rail is able to cause a fatal disaster. Therefore, the differential settlement of the embankment must be controlled with the greatest care. Furthermore, the characteristics and causes of settlements which occurred under construction and post-construction should be investigated. A considerable number of studies have been conducted on the settlement of the natural ground over the past several decades. But little attention has been given to the compression settlement of the embankment. The long-term settlement of compacted fills embankments is greatly influenced by the post-construction wetting. This is called 'hydro collapse' or 'wetting collapse'. In spite of little study for this wetting collapse problem, it has been recognized that the compressibility of compacted sands, gravels and rockfills exhibit low compressibility at low pressures, but there can be significant compression at high pressures due to grain crushing (Marachi et al. 1969, Nobari and Duncan 1972, Noorany et al. 1994, Houston et al. 1993, Wu 2004). The characteristics of compression of fill materials depend on a number of factors such as soil/rock type, as-compacted moisture, density, stress level and wetting condition. Because of the complexity of these factors, it is not easy to predict quantitatively the amount of compression without extensive tests. Therefore, in this research I carried out the wetting collapse tests, focusing on various soil/rock type, stress levels, wetting condition more closely.