• Economic and Environmental Geology
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• v.50 no.6
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• pp.545-554
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• 2017

Birnessite is one of the dominant Mn (oxyhydr)oxide phases commonly found in soil and deep ocean environments. It typically occurs as nano-sized and poorly crystalline aggregates in the natural environment. It is well known that birnessite participates in a wide variety of bio/geochemical reactions as a reactive mineral phase with structural defects, cation vacancies, and mixed valences of structural Mn. These various bio/geochemical reactions control not only the fate and transport of inorganic and organic substances in the environment, but also the formation of diverse Mn (oxyhydr)oxides through birnessite transformation. This review assessed and discussed about the phase transformation of birnessite under a wide range of environmental conditions and about the potential geochemical factors controlling the corresponding reactions in the literature. Birnessite transformation to other types of Mn (oxyhydr)oxides were affected by dissolved Mn(II), dissolved oxygen, solution pH, and co-existing cation (i.e., $Mg^{2+}$). However, there still have been many issues to be unraveled on the complex bio/geochemical processes involved in the phase transformation of birnessite. Future work on the detail mechanisms of birnessite transformation should be further investigated.

• Journal of Life Science
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• v.20 no.6
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• pp.838-844
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• 2010

A fibrinolytic enzyme of Streptomyces corcohrussi from soil sediment was purified by chromatography using DEAE-Sephadex A-50 and Sephadex G-50. The analysis of SDS-polyacrylamide gel suggested that the purified enzyme is a homogeneous protein and the molecular mass is approximately 34 kDa. The purified enzyme showed activity of 0.8 U/ml in a plasminogen-rich fibrin plate, while its activity in a plasminogen-free fibrin plate was only 0.36 U/ml. These results suggested that the purified enzyme acts as a plasminogen activator. The fibrinolytic activity of the enzyme under the supplementation of protease inhibitors, $\varepsilon$-ACA, t-AMCHA and mercuric chloride in the enzyme reaction was less than 24%, indicating that it could be modulated by the plasmin and/or fibrinogen inhibitors involved in the fibrinogen-to-fibrin converting process. As time passed, $Zn^{2+}$, a heavy metal ion, inhibited the activity to 34.1%. The optimum temperature of the purified enzyme was approximately $50^{\circ}C$ and over 92% of the enzyme activity was maintained between pH 5.0 and 8.0. Therefore, our results provide a potential fibrinolytic enzyme as a noble thrombolytic agent from S. corcohrussi.

• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.326-331
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• 1989

Superconducting fiber of high Tc $YBa_2Cu_3O_{7-{\sigma}}$ was successfully prepared by the sol-gel method. The stoichiometric mixture of Y, Ba and Cu nitrates was dissolved in water, to which citric acid solution was added. Then ammonium hydroxide was added to the mixture in order to increase the pH to a value between 5.8 and 6.2. The mixture was heated carefully to form a homogeneous colloid sol at 358 K. The solution was viscous enough to draw a long gel fiber, which was then heated at 1223K for 8 hrs. under oxygen partial pressure of $Po_2$ = 1 atm., cooled slowly and annealed at 723K for 13 hrs.. The reacted superconducting sample maintained a fiber form with some shrinkage of its volume. The superconducting transition temperatures (Tc, onset and Tc, offset) of $YBa_2Cu_3O_{7-{\sigma}}$ have been determined to be approximately 95K and 82K, respectively. The superconducting phase was also confirmed by Meissner effect at liquid nitrogen boiling temperature.

• Proceedings of the Ginseng society Conference
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• 1984.09a
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• pp.1-11
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• 1984

Ginseng cotyledon calli were cultured on 1/2MS media supplemented with combination of various growth regulators to induce more embryoids and plantlets in a short period. And tissues of ginseng root and calli were also incubated under various factors or conditions to establish methods for the isolation of viable protoplasts in Panax ginseng C.A. Meyer. The calli derived from cotyledon produced numerous embryoids in 1/2MS media containing 0.5mg/$\ell$ 2,4-D and 0.5mg/$\ell$ kinetin after 2 months' culture. But only shoot formation was less frequent. Further development of these embryoids occurred on 1/2MS medium supplemented with the same concentration of BA and GA. Viable protoplasts were isolated from the root tissue and callus of ginseng. The specific conditions for the isolation of viable protoplasts were required of ginseng materials, root tissue and callus, being processed. For the production of viable protoplasts from 1-year old ginseng root tissue, an enzyme mixture of $2\%$ cellulase 'Ono-zuka' and $0.5\%$ macerozyme, an enzyme solution pH of 5.2 to 5.8, a 7- to 8- hour incubation period at $28{\pm}1^{\circ}C$, and 0.9M mannitol as osmoticum in the cell enzyme mixture were optimum, while the treatments with an enzyme mixture of $2\%$ cellulase 'Onozuka', $2\%$ macerozyme and $1\%$ driselase, and 25-hour incubation period at $28{\pm}1^{\circ}C$, were more efficient for the production of viable protoplasts from ginseng callus.

• Food Science and Preservation
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• v.20 no.5
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• pp.636-642
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• 2013

Quality and sensory characteristics of tofu prepared with concentrated to 8 $^{\circ}Brix$ deep ground sea-like water (SW) were investigated to check the availability for coagulants. The tofu was coagulated with three kinds of commercially coagulant, such as $MgCl_2$, $CaSO_4$ and glucono-${\delta}$-lactone. Different amounts of SW and soybean milk were added: SW-20 g/L, SW-25 g/L and SW-30 g/L. The moisture content and pH were significantly lower in which preparation with glucono-${\delta}$-lactone coagulated tofu, and others has not significantly difference each other. The mineral contents in the coagulant influenced the mineral content of the tofu, which contained larger quantities of major minerals. However, the mineral content of the tofu was not affected of the mineral concentration in the coagulant. The L and b values of the tofu prepared with SW were not significantly different. The hardness of the tofu prepared with the commercial coagulants was significantly lower than that of the tofu produced with the SW. The sensory property was lower when the hardness was lower and higher. In conclusion, the quality characteristics of SW-prepared tofu were not significantly different from those of the tofu prepared with the commercial coagulants, but the texture and the taste of the SW-prepared tofu were excellent.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.67-74
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• 2016

The Prussian Blue Analogue(PBA) has three dimensional structure and the metal - organic framework material, and it has a variety configurations depending on the type of organic ligands. PBA has been receving an attention in the fields of biosensors, optical, catalytic, and hydrogen storage device. Also, it is an environmental friendly substance with a chemical stability. In addition, PBA is widely used in the filed of adsorption art since we can adjust the size of the fine pores. In this study, we synthesized $Mn_3[Fe(CN)_6]_2$, an organometallic framework chains by using a hydrothermal synthesis method. We used $K_4[Fe(CN)_6]$ and $MnCl_2$ as precursors. We also produced a manganese iron oxide, by baking the synthesized material. The effect of the size and shape of the particles was examined by controling pH of the precursor solution, the molar concentration of the precursor, and reaction time as the experimental variables. Synthesized absorbent was analyzed by XRD, SEM, FT-IR, UV-Vis, and TG / DTA to evaluate the adsorption properties of several dyes.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.355-361
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• 1991

The separative preconcentration of trace mercury[Hg(II)] in a water sample was studied by a coprecipitation flotation technique. The trace Hg(II) was precipitated together with Ce(OH)$_3$ by adding 3.0 ml of 0.1M Ce$^{3+}$ solution to 1,000 ml of water sample and adjusting pH to 11.0 with 1.0M NaOH solution. The hydrophobic precipitate[Ce(OH)$_3$-Hg(OH)$_2$], which was formed by adding 2.0 ml of 0.1${\%}$ ethanolic sodium oleate solution, were floated on the surface with an aid of tiny nitrogen gas bubbles. The floated materials were quatitatively collected in a suction flask and dissolved with 5.0 ml of 2.0M HNO$_3$. The solution was marked to 25.00 ml with a deionized water. The content of Hg(II) was determined by cold vapor atomic absorption spectrophotometry. Any interferences of concomitants such as Ag$^+$, Br$^-$, I$^- $, etc. were not observed on the whole procedure. The analytical result showed that Hg(II) found in the wastewater of Seochang Campus, Korea University was 1.98 ng/ml with the relative standard deviation of 3.6${\%}$. And recoveries of Hg(II) in the wastewater into which 1.0 ng/ml and 2.0 ng/ml were added were 95${\%}$ and 91${\%}$, respectively. From such results, this procedure could be concluded to be tolerably accurate and reproducible for the determination of trace mercury in a water sample.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.426-431
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• 2013

Nanosized $TiO_2$ particles were prepared from titanium (IV) sulfate solution using base solutions at low reaction temperature ($95^{\circ}C$) and atmospheric pressure by hydrothermal precipitation method without calcination. The effects of preparation conditions, such as kind of base solutions (NaOH, $NH_4OH$, Monoethanolamine, Diethanolamine, Triethanolamine) and surfactants (CTAB, Span 20, SDBS), concentration of surfactants, temperature and pH, on the physical properties of $TiO_2$ particles have been investigated by XRD, SEM and Zeta-potential meter. Absorption area was also investigated by DRS in order to confirm the photocatalytic activity of the nanosized $TiO_2$ particles. It was turned out that, among base solutions, NaOH provides the smallest $TiO_2$ particles with excellent crystallinity. And cationic surfactant (CTAB) prepared smaller $TiO_2$ particles than any other surfactants. When CTAB is added in the concentration ratio of $Ti(SO_4)_2$:CTAB=10:1, $TiO_2$ particles with particle diameter of 5.8 nm were prepared. This is approximately 1/10 of that prepared without CTAB.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.372-376
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• 2009

Physicochemical changes in persimmon were examined during natural organic acid fermentation. Major organic acids in raw persimmon juices were lactic acid (980 mg%) and acetic acid (245 mg%). The content of acetic acid was continuously increased during the whole period of fermentation up to 3 years. Glucose was the dominant free sugar, but the content was decreased after 20 days of fermentation. Most of the glucose was converted to ethanol until 40 days after initiation of acid fermentation. L- and a values of Hunter's color in fermented persimmon juice, which was naturally exuded from persimmon fruit as fermentation continued, increased gradually, while b value decreased. Acetic acid (1584 mg%) was the most abundant organic acid followed by lactic acid (712 mg%) and citric acid (48 mg%) in a persimmon fruit juice after completion of 3 year fermentation. A minute amount of residual free sugars, mainly glucose, even after 3 years of fermentation may cause changes in quality characteristics while storage for edible use.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.356-362
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• 2010

When pine (Pinus densiflora) needles were fractionated into cold water (PD-CW), hot water (PD-HW) and methanol extract (PD-M), PD-M showed potent simulating activity (1.19-fold of the saline control) for proliferation of bone marrow cells mediated by Peyer's patch cells in vitro. MeOH extracts were prepared by homogenization, stirring or reflux to identify the method of methanol extraction, and MeOH extract by reflux method showed significantly highest intestinal immune system modulating activity (1.30-fold) in vitro. The intestinal immune system modulating effect of orally administered PD-M fractionated from pine needles also were studied in mice. Analyzing intestinal immune system modulating activity mediated Peyer's patch cells from C3H/He mice which had been fed with PD-M at different doses for 7 days, 1.0 g/kg of BW/day indicated that the bone marrow cells had proliferated (3.65-fold of 3% EtOH administered group). In addition, the amounts of IL-6 in the culture supernatant of Peyer's patch cells at 1.0 g/kg of BW/day were increased (1.13-fold) whereas the production of GM-CSF was not dose dependent. These results indicate that oral administration of PD-M enhances the secretion of hematopoietic growth factors such as GM-CSF and IL-6 from Peyer's patch cells, and these cytokines also act on modulator of bone marrow cell proliferation.