• Journal of the Geological Society of Korea
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• v.54 no.6
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• pp.615-630
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• 2018

Basin analysis is a research field to understand the formation and evolution of sedimentary basins. This task requires various geoscientific datasets as well as numerical and graphical modelling techniques to synthesize results dimensionally in time and space. For basin analysis and modelling in a comprehensive workflow, BasinVis 1.0 was released as a MATLAB-based program in 2016, and recently the software has been extended to BasinVis 2.0, with new functions and revised user-interface. As a case study, this work analyses the southern Vienna Basin and visualizes the sedimentation setting and subsidence evolution to introduce the basin modelling functions of BasinVis 2.0. This is a preliminary study for a basin-scale modelling of the Vienna Basin, together with our previous studies using BasinVis 1.0. In the study area, during the late Early Miocene, sedimentation and subsidence are significant along strike-slip and en-echelon listric normal faults. From the Middle Miocene onwards, however, subsidence decreases abruptly over the area and this situation continues until the Late Miocene. This is related to the development of the pull-apart system and corresponds to the episodic tectonic subsidence in strike-slip basins. The subsidence of the Middle Miocene is confined mainly to areas along the strike-slip faults, while, from the late Middle Miocene, the depocenter shifts to a depression along the N-S trending listric normal faults. This corresponds to the regional paleostress regime transitioning from NE-SW trending transtension to E-W trending extension. This study applies various functions and techniques to this case study, and the modelled results demonstrate that BasinVis 2.0 is effective and applicable to the basin modelling.

• Biomaterials Research
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• v.22 no.4
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• pp.328-336
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• 2018

Background: Biogenic fabrication of silver nanoparticles from naturally occurring biomaterials provides an alternative, eco-friendly and cost-effective means of obtaining nanoparticles. It is a favourite pursuit of all scientists and has gained popularity because it prevents the environment from pollution. Our main objective to take up this project is to fabricate silver nanoparticles from lichen, Usnea longissima and explore their properties. In the present study, we report a benign method of biosynthesis of silver nanoparticles from aqueous-ethanolic extract of Usnea longissima and their characterization by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses. Silver nanoparticles thus obtained were tested for antimicrobial activity against gram positive bacteria and gram negative bacteria. Results: Formation of silver nanoparticles was confirmed by the appearance of an absorption band at 400 nm in the UV-vis spectrum of the colloidal solution containing both the nanoparticles and U. longissima extract. Poly(ethylene glycol) coated silver nanoparticles showed additional absorption peaks at 424 and 450 nm. FTIR spectrum showed the involvement of amines, usnic acids, phenols, aldehydes and ketones in the reduction of silver ions to silver nanoparticles. Morphological studies showed three types of nanoparticles with an abundance of spherical shaped silver nanoparticles of 9.40-11.23 nm. Their average hydrodynamic diameter is 437.1 nm. Results of in vitro antibacterial activity of silver nanoparticles against Staphylococcus aureus, Streptococcus mutans, Streptococcus pyrogenes, Streptococcus viridans, Corynebacterium xerosis, Corynebacterium diphtheriae (gram positive bacteria) and Escherichia coli, Klebsiella pneuomoniae and Pseudomonas aeruginosa (gram negative bacteria) showed that it was effective against tested bacterial strains. However, S. mutans, C. diphtheriae and P. aeruginosa were resistant to silver nanoparticles. Conclusion: Lichens are rarely exploited for the fabrication of silver nanoparticles. In the present work the lichen acts as reducing as well as capping agent. They can therefore, be used to synthesize metal nanoparticles and their size may be controlled by monitoring the concentration of extract and metal ions. Since they are antibacterial they may be used for the treatment of bacterial infections in man and animal. They can also be used in purification of water, in soaps and medicine. Their sustained release may be achieved by coating them with a suitable polymer. Silver nanoparticles fabricated from edible U. longissima are free from toxic chemicals and therefore they can be safely used in medicine and medical devices. These silver nanoparticles were stable for weeks therefore they can be stored for longer duration of time without decomposition.

• Journal of Korean Philosophical Society
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• v.126
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• pp.79-108
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• 2013

Is the development of linguistic competence due to the learning process or the maturational process? According to Piaget, its development is a genuine learning process involving authentic constructions with gradual disclosure of new possibilities. But According to Chomsky, the acquisition of linguistic competence is due to a genetically conditioned maturational process. So it merely involves the actualization of a set of possibilities existing from the beginning Consequently, Piaget supposes that interaction with the environment plays a shaping role, while Chomsky allows it to have a mere triggering role. In broad respective, Chomsky supposes the rationalism that knowledge is largely inborn, while Piaget in the constructivist position which strives to find a middle course between radical rationalism and radical empiricism. In the one hand, an ultra-rationalistic concept such as 'fixed nucleus' supposed by Chomsky is, in my eye, nor plausible. In the other hand, if Piagetian constructivism is to be sustained, it must be sustained independently of its dubious biological fundament, and merely as a developmental psychological theory. In one word, we need to synthesize Piagetian cognitive approach and Chomskian syntactical, in order to explain exactly the source of human linguistic competence.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.25-33
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• 2005

Melanocytes synthesize melanin within discrete organelle termed melanosomes which are transferred to the surrounding keratinocytes and can be produced in varying sizes, numbers and densities. Skin whitening products have become increasingly popular in the past few years. The most successful natural skin whitening agents are: arbutin, vitamin C, kojic acid, and mulberry, which are all tyrosinase inhibitors. In this work, melanoston, a melanogenesis inhibitor isolated from yeast was studied to understand its mechanism of melanogenesis inhibition. It was found that melanoston was not a tyrosinase inhibitor, while when melanoston was applied to the B16 melanoma cell culture media, the intracellular tyrosinase activity was decreased by more than $30\%$. When B16 melanoma was stimulated with $\alpha$-MSH, cell morphololgy was dramatically changed to have lots of dendrites on the cell membrane surface. On the other hand, B16 was treated with $\alpha$-MSH and melanoston, simultaneously, the change of cell morphologv was not so great. This inhibitory effect of melanoston was found to be related to the inhibition of intracellar activation and transportation of tyrosinase, which was observed by irmmunostaining of B16 melanoma using anti-tyrosinase antibody. From these results, melanoston was regarded as an inhibitor to the differentiation of melanoma cells.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.524-531
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• 2021

Depending on the type and amount of acid used as a modulator in the manufacturing process, the structural properties of UiO-66 can be modified and the adsorbability of chemical warfare agents can be enhanced. In this study, several acids as a modulator were used to synthesize UiO-66. Their properties were analyzed with FT-IR, XRD, titrator, and adsorption isotherms using chemical warfare agent simulant, DIMP. The UiO-66, structurally damaged by hydrochloric acid as a modulator, showed lower crystallinity and DIMP adsorption capacity and also smaller specific surface area and volume of voids compared to those of UiO-66, which was manufactured using acetic acid, and formic acid as a modulator. Additionally, UiO-66 which was synthesized by adding formic acid and hydrochloric acid as a modulator, showed the highest DIMP adsorption capacity and is likely to be used as an adsorbent for chemical warfare agent in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.114-126
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• 2021

This paper compared bridge maintenance in United Stated, United Kingdom, Japan, and Korea. Bridges play an essential role in transportation network and in the economic production process. To provide a desirable level of service to the public within limited budgets, it is required to provide effective bridge maintenance activities (e.g. inspection and repair/rehabilitation) at acceptable level of bridge service. A number of bridges are expected to age rapidly in Korea, which will be the excess burden of government. Since several countries have experienced a number of deteriorated bridges because of aging, the countries aforementioned in this study have already developed comprehensive bridge maintenance programs such as inspection practice and repair/rehabilitation techniques. Therefore, the goal of this paper is to synthesize and to compare useful knowledge on bridge maintenance and bridge crack repair/restoration of deteriorated concrete bridge in the four countries. Finally, recommendations that will serve as guidance to transportation agencies for potential enhancements to bridge maintenance and bridge repairs are presented.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.116-124
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• 2019

Background: Ginsenosides are known as the principal pharmacological active constituents in Panax medicinal plants such as Asian ginseng, American ginseng, and Notoginseng. Some ginsenosides, especially the 20(R) isomers, are found in trace amounts in natural sources and are difficult to chemically synthesize. The present study provides an approach to produce such trace ginsenosides applying biotransformation through Escherichia coli modified with relevant genes. Methods: Seven uridine diphosphate glycosyltransferase (UGT) genes originating from Panax notoginseng, Medicago sativa, and Bacillus subtilis were synthesized or cloned and constructed into pETM6, an ePathBrick vector, which were then introduced into E. coli BL21star (DE3) separately. 20(R)-Protopanaxadiol (PPD), 20(R)-protopanaxatriol (PPT), and 20(R)-type ginsenosides were used as substrates for biotransformation with recombinant E. coli modified with those UGT genes. Results: E. coli engineered with $GT95^{syn}$ selectively transfers a glucose moiety to the C20 hydroxyl of 20(R)-PPD and 20(R)-PPT to produce 20(R)-CK and 20(R)-F1, respectively. GTK1- and GTC1-modified E. coli glycosylated the C3-OH of 20(R)-PPD to form 20(R)-Rh2. Moreover, E. coli containing $p2GT95^{syn}K1$, a recreated two-step glycosylation pathway via the ePathBrich, implemented the successive glycosylation at C20-OH and C3-OH of 20(R)-PPD and yielded 20(R)-F2 in the biotransformation broth. Conclusion: This study demonstrates that rare 20(R)-ginsenosides can be produced through E. coli engineered with UTG genes.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.389-397
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• 2018

The starfish, Asterina pectinifera Muller and Troschel (Asterinidae) is an indigenous species commonly found in all coasts of Korea causes damages to shellfish farms. In order to exterminate A. pectinifera, they are dried and used as fertilizer. Although various studies have been conducted to create high added value from the retrieved A. pectinifera, their actual utilization is relatively low. Accordingly, this study aimed to find new practical uses of starfish by identifying useful ingredients for skin anti-aging. Two polyhydroxysteroids and one asterosaponin were isolated from the A. pectinifera. The structures of these compounds were identified as $5{\alpha}$-cholestane-$3{\beta},6{\alpha},7{\alpha},8,15{\alpha},16{\beta},26$-heptol, $5{\alpha}$-cholestane-$3{\beta},4{\beta},6{\alpha},7{\alpha},8,15{\beta},16{\beta},2$6-octol, and asterosaponin $P_1$ on the basis of chemical and spectroscopic analysis. Among these compounds, we have found that asterosaponin $P_1$ increased epidermal stem cell proliferation and the expression of hyaluronan synthase-2 and hyaluronan synthase-3 gene, which are enzymes that synthesize water-binding matrix hyaluronic acids in keratinocytes. In addition, asterosaponin $P_1$ increased synthesis of pro-collagen type I, a major dermal collagen in fibroblasts. As a result, asterosaponin $P_1$ isolated from A. pectinifera could be used as a useful cosmetic ingredient that improves skin symptoms accompanying skin aging.

• Korean Journal of Materials Research
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• v.29 no.2
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• pp.92-96
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• 2019

Transition metal oxide is widely used as a water electrolysis catalyst to substitute for a noble metal catalyst such as $IrO_2$ and $RuO_2$. In this study, the sol-gel method is used to synthesize the $Cu_xCo_{3-x}O_4$ catalyst for the oxygen evolution reaction (OER),. The CuxCo3-xO4 is synthesized at various calcination temperatures from $250^{\circ}C$ to $400^{\circ}C$ for 4 h. The $Cu_xCo_{3-x}O_4$ synthesized at $300^{\circ}C$ has a perfect spinel structure without residues of the precursor and secondary phases, such as CuO. The particle size of $Cu_xCo_{3-x}O_4$ increases with an increase in calcination temperature. Amongst all the samples studied, $Cu_xCo_{3-x}O_4$, which is synthesized at 300?, has the highest activity for the OER. Its onset potential for the OER is 370 mV and the overpotential at $10mA/cm^2$ is 438 mV. The tafel slope of $Cu_xCo_{3-x}O_4$ synthesized at $300^{\circ}C$ has a low value of 58 mV/dec. These results are mainly explained by the increase in the available active surface area of the $Cu_xCo_{3-x}O_4$ catalyst.

• Journal of Conservation Science
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• v.34 no.6
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• pp.581-593
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• 2018

Studies on ancient iron production technologies still have challenges to overcome, although there have been many results that have enabled us to understand these old technologies. The purpose of this study is to propose a suitable temperature condition for smelting experiments. The target for reconstruction is a smelting-smithing process in the ancient Jungwon area, and the experiment was designed on the basis of published research, such as archaeological evidence. Experiment A was performed at a low temperature to produce low-carbon iron, while Experiment B was conducted at a relatively high temperature to synthesize high-carbon iron. In addition, the low-carbon iron proved to be suitable for the smithing process. Moreover, aspects such as the microstructure and chemical composition of the slag and the surface condition of the furnace wall showed that the low-temperature smelting process was closer to the ancient method. It is important to mention the premise that the reconstruction of ancient technology can be achieved when the results of an experiment replicate the conditions of a real site. The results show that direct smelting, which produces low-carbon iron bloom under a low-temperature condition, should be the subject of smelting experiments concerning the iron production technologies of the ancient Jungwon area.