• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.138-164
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• 2022

The Neolithic shell midden in Daejuk-ri, Seosan, is distributed on the gentle slope of a low hill close to the west coast. The bedrock of the area consists mainly of schist with various mafic minerals, but shows a partial gneiss pattern. The site consists of loamy topsoil and clay loam subsoil, and the degree of siallization is relatively low. Although the pottery excavated from the shell midden shares mostly similar features, a variety of shapes and patterns coexist. The surface colors, thickness and physical properties are slightly different. The pottery can be subdivided into three types (IA, IB and II) according to the composition of the body clay, the temper and the existence of a black core. Types IA and IB are colorless mineral pottery with a non-black or black core respectively. TypeII is colored mineral pottery with a non-black core. Type I pottery also contains non-plastic colored minerals, but type II contains a large amount of biotite, chlorite, talc, amphibole, diopside and tremolite, which include a large amount of Mg and Fe. The studied pottery contains a small amount of organic matter. Considering the grain size and relatively poor sorting and roundness of the non-plastic particles, the pottery appears to be made by adding coarse non-plastic tempers for special purposes to the untreated weathered soil around the site. The three types of pottery seem to have been incompletely fired in general. While type IB has the lowest degree of oxidation, typeII shows the highest degree of redness and oxidation. It can be interpreted that these differences depend on the firing temperature and the ratio of non-plastic particles. Through a synthesis of the minerals, geochemical data and thermal history, it can be determined that the firing temperature ranged from 600 to 700℃. The pottery types of the Daejuk-ri Shell Midden have slightly different production conditions, mineral compositions, and physical properties, but have undergone similar production processes with basically the same clay materials. The clay is almost identical to the composition of the bedrock and weathered soil distributed in the Daejuk-ri area. Currently, there is an industrial complex in the area, so it is difficult to confirm the soil and geological distribution of the site. However, it is highly probable that the area around the site was self-sufficient for the clay and tempers required for the production of the Neolithic pottery. Therefore, it can be interpreted that the group that left the shell midden in Daejuk-ri lived near the site, visited the site for the purpose of collecting and processing shellfish, and discarded the broken pottery along with shells.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.452-460
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• 2016

This study was designed to develop a functional pharma-food using Salicornia europaea (SE). Tiny seeds from the mature SE were collected, and their biological activities were evaluated. The extraction yield of the seed in hot water was found to be 29.6% and the hot water extract (HWE) contained 25.7 mg/g total polyphenol (TP) and 11.5 mg/g total flavonoid (TF), which are similar to those contained in leaf and stem of SE. Among the subsequent organic solvent fractions, the ethylacetate (EA) fraction exhibited the highest content of TP (158.3 mg/g), TF (136.2 mg/g), and total sugar (228.3 mg/g). The EA fraction exhibited broad-range antibacterial activities against gram-positive bacteria, and the butanol fraction exhibited growth inhibitory effect against only Staphylococcus epidermidis. An antioxidation activity assay of the HWE and its fractions showed the EA fraction to have the highest radical scavenging activity with $RC_{50}$ values of 57.0, 29.0, and $28.9{\mu}g/ml$ against DPPH anion, ABTS cation, and nitrite, respectively. The $RC_{50}$ values of vitamin C against DPPH anion, ABTS cation, and nitrite were 10.7, 4.0, and $18.0{\mu}g/ml$, respectively, indicating that the EA fraction of SE has potent antioxidant compounds. In an anticoagulation assay, the EA fraction exhibited a 15-fold extended thrombin time at 5 mg/ml and activated partial thromboplastin time at 7 mg/ml, which are comparable to the activities of aspirin. The HWE and its fractions had no hemolysis activities against human RBCs at up to 1 mg/ml. These results suggest that the EA fraction from SE has a great potential as a new antibacterial and anticoagulation agent.

• Tuberculosis and Respiratory Diseases
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• v.58 no.1
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• pp.31-42
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• 2005

Background : Peroxiredoxins (Prxs) are a relatively newly recognized, novel family of peroxidases that reduce $H_2O_2$ and alkylhydroperoxide into water and alcohol, respectively. There are 6 known isoforms of Prxs present in human cells. Normally, Prxs exist in a head-to-tail homodimeric state in a reduced form. However, in the presence of excess $H_2O_2$, it can be oxidized on its catalytically active cysteine site into inactive oxidized forms. This study surveyed the types of the Prx isoforms present in the pulmonary epithelial, macrophage, endothelial, and other cell lines and observed their response to oxidative stress. Methods : This study examined the effect of exogenous, excess $H_2O_2$ on the Prxs of established cell lines originating from the pulmonary epithelium, macrophages, and other cell lines, which are known to be exposed to high oxygen partial pressures or are believed to be subject to frequent oxidative stress, using non-reducing SDS polyacrylamide electrophoresis (PAGE) and 2 dimensional electrophoresis. Result : The addition of excess $H_2O_2$ to the culture media of the various cell-lines caused the immediate inactivation of Prxs, as evidenced by their inability to form dimers by a disulfide cross linkage. This was detected as a subsequent shift to its monomeric forms on the non-reducing SDS PAGE. These findings were further confirmed by 2 dimensional electrophoresis and immunoblot analysis by a shift toward a more acidic isoelectric point (pI). However, the subsequent reappearance of the dimeric Prxs with a comparable, corresponding decrease in the monomeric bands was noted on the non-reducing SDS PAGE as early as 30 minutes after the $H_2O_2$ treatment suggesting regeneration after oxidation. The regenerated dimers can again be converted to the inactivated form by a repeated $H_2O_2$ treatment, indicating that the protein is still catalytically active. The recovery of Prxs to the original dimeric state was not inhibited by a pre-treatment with cycloheximide, nor by a pretreatment with inhibitors of protein synthesis, which suggests that the reappearance of dimers occurs via a regeneration process rather than via the de novo synthesis of the active protein. Conclusion : The cells, in general, appeared to be equipped with an established system for regenerating inactivated Prxs, and this system may function as a molecular "on-off switch" in various oxidative signal transduction processes. The same mechanisms might applicable other proteins associated with signal transduction where the active catalytic site cysteines exist.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.223-231
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• 1994

In order to develop the squid(Todarodes pacificus) sik-hae, the changes of TBA, fatty acids, free amino acids, and the number of microflora fermented at different fermentation temperatures and periods were determined. In addition, pretense from squid sik-hae was partially purified. The number of TBA was the highest after 5-day storage and decreased after that, and lipid oxidation was the highest at $10^{\circ}C$. The amounts of linoleic aid(18:2) and oleic acid (18:1) were about $60\%$ of fatty acid composition of squid sik-hae, and linolenic acid(18:3) and EPA(20:5) significantly decomposed with increasing fermentation periods and temperatures. Pro, His, Aeg, Leu, and Glu were composed mainly of amino acid and the composition ratios of Ser, His, and Arg decreased with increasing fermentation periods whereas, those of Glu, Ala, Val, and Tyr increased. The composition ratios of Glu, Val, and Met increased with increasing fermentation temperatures whereas, those of Ala, Cys, Thr, and Gly decreased. The number of microflora generally increased up to 15-days of storage and decreased after that. The rates of increass and decreass of the microbial number increased in proportion to fermentation temperatures. In addition, the bacteria producing proteases were identified as Bacillus spp. Proteases from $60{\sim}80\%$ ammonium sulfate concentration showed the highest activity and had about 15 binds with molecular weights between 20,000 and 40,000 Dalton by the SDS-PAGE.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.59-64
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• 2003

We fabricated mixed ionic-electronic conducting membranes, $CH_4\;Using\;{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$, by solid state reaction method for solid oxide fuel cell. The membranes consisted of single perovskite phase and exhibited high relative density, $>95\%$. We coated $La_{0.6}Sr_{0.4}CoO_{3-\delta}$ layer using screen printing method in order to improve surface reactivity of the $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$. As a result, the oxygen permeation flux of the coated $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$ showed higher value, $0.5ml/min{\cdot}cm^2\;at\;950^{\circ}C$ than the uncoated one. Higher oxygen permeation was observed in the porously coated Lao $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$membranes with larger grain sizes. Syngas, $CO+H_2$, was successfully obtained from methane gas, $CH_4$, using the $La_{0.6}Sr_{0.4}CoO_{3-\delta}$ coated $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$, with over $40\%\;of\;CH_4$ conversion and syngas yield. $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$ membrane was stable even when it was exposed to the reducing environment, methane, for 600 hrs at $950^{\circ}C$.

• Journal of Life Science
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• v.27 no.2
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• pp.131-138
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• 2017

In this study, for the efficient use of the byproduct of the omija (Schizandra chinensis Baillon: SC) processing industry, the ethanol extracts of the fruit (F), seed (S), and pomace (P) of SC were prepared, and their useful bioactivities were evaluated. For F-SC, S-SC, and P-SC, the extraction yields were 28.3%, 22.1%, and 7.2%, respectively, and the polyphenol contents were 8.81, 37.22, and 9.20 mg/g, respectively. The total flavonoid content in P-SC (4.31 mg/g) was 3.5-fold higher than that in F-SC (0.76 mg/g). In an antioxidation activity assay, P-SC showed stronger radical scavenging activities against DPPH anion, ABTS cation, and nitrite and stronger reducing power activities than the other extracts. The calculated concentration required for 50% radical scavenging activity, $RC_{50}s$, of P-SC for DPPH anion, ABTS cation, and nitrite was 226.2, 192.5, and $92.5{\mu}g/ml$, respectively. In an antimicrobial activity assay, F-SC, S-SC, and P-SC showed similarly strong growth inhibitions against Bacillus subtilis and P. vulgaris at a concentration of 0.5 mg/disc. F-SC and P-SC showed 15-fold extended time in thrombin, prothrombin, and activated partial thromboplastin time assays at a concentration of 5 mg/ml. The anticoagulation activity of P-SC (2.5 mg/ml) was comparable to that of aspirin (1.5 mg/ml). Furthermore, F-SC and S-SC showed very good platelet aggregation inhibitory activities. F-SC, S-SC, and P-SC did not show significant hemolysis against human red blood cell up to a concentration of 0.5 mg/ml. These results suggest that S-SC and P-SC, both of which are byproducts of the omija processing industry, show strong potential as novel antioxidant, antimicrobial, and antithrombosis agents.

• Korean Journal of Plant Resources
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• v.22 no.5
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• pp.403-411
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• 2009

This study was conducted to gather the basic data on the increase of utilization for the Japanese staunton vine (Stauntonia hexaphylla), native plants which were grown in the southern districts in Korea. We have also determined their partial physical and chemical compositions and their physiological activities. Vitamin C contents in fruit skin was 85.23 mg/100 g, and that in flesh was 61.67 mg/100 g. Total amino acids contents in fruit skin increased much more by 762.72 mg/100 g DW compared to that in flesh by 434.05 mg/100 g DW. Inorganic matter contents were more increased in the fruit skin (108.48 mg/$\ell$) and its main components were K (76.53 mg/$\ell$), Ca (20.20 mg/$\ell$) and Mg (6.22 mg/$\ell$). Total phenol compound and flavonoid contents in 1,000 mg/$\ell$ methanol extracts were 7.3-9.6 mg/$\ell$ and 5.1-6.7 mg/$\ell$. Nitrite radical scavenging activity in 4,000 mg/$\ell$ methanol extracts of fruit skin and flesh for Stauntonia hexaphylla were 79.5% and 77.8%, however, that in seeds was 17.1%. Overall mushroom tyrosinase inhibition activity (% of control) was less than 10.8%. Anti-microbial activities of methanol extracts from the fruit skin against the gram negative and positive microbial strains were not significant in the lower concentration of extracting solution, however, that from flesh and seeds in terms of the inhibition diameter were $8.91{\sim}12.25\;mm$.

• Clean Technology
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• v.21 no.1
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• pp.68-75
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• 2015

In this study, we investigated the structure and properties of a highly heat conductive metal-ceramic core-shell CoAl₂O₄@Al micro-composite for heterogeneous catalysts support. The CoAl₂O₄@Al was prepared by hydrothermal surface oxidation of Al metal powder, which resulted in the structure with a high heat conductive Al metal core encapsulated by a high surface area CoAl₂O₄ shell. For comparison, CoAl₂O₄ was also prepared by co-precipitation method and also utilized for a catalyst support. Rh catalysts supported on CoAl₂O₄@Al and CoAl₂O₄ were prepared by incipient wetness impregnation and characterized by N₂ adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), CO chemisorption, and temperature-programmed reduction (TPR). The properties of catalysts were investigated for glycerol steam reforming reaction for hydrogen production at 550 ℃. Rh/CoAl₂O₄@Al exhibited about 2.8 times higher glycerol conversion turnover frequency (TOF) than Rh/CoAl₂O₄ due to facilitated heat transport through the core-shell structure. The CoAl₂O₄@Al and CoAl₂O₄ also showed some catalytic activities due to a partial reduction of Co on the support, and a higher catalytic activity was also found on the CoAl₂O₄@Al core-shell than CoAl₂O₄. These catalysts, however, displayed deactivation on the reaction stream due to carbon deposition on the catalysts surface.