• KSBB Journal
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• v.22 no.6
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• pp.438-442
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• 2007

A biosensor using electrochemically-active bacteria (EAB) enriched in three-electrode electrochemical cell, was developed for the determination of biochemical oxygen demand (BOD) in wastewater. In the electrochemical cell, the positively poised working electrode with applying a potential of 0.7 V was used as an electron acceptor for the EAB. The experimental results using artificial and raw wastewater showed that the current pattern generated by the biosensor and its Coulombic yield were proportional to the concentration of organic matter in wastewater. The correlation coefficients of BOD vs Coulombic yield and $BOD_5$ vs Coulombic yield were 0.99 and 0.98, respectively. These results indicate that the biosensor enriched with the EAB capable of transferring electrons directly toward the electrode can be utilized as a water-quality monitoring system due to a quick and accurate response.

• Membrane Journal
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• v.32 no.1
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• pp.43-49
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• 2022

Solid-state supercapacitors with high safety and robust mechanical properties are attracting global attention as next-generation energy storage devices. As an electrode of a supercapacitor, an economical carbon-based electrode is widely used. However, when an aqueous electrolyte is introduced, the charge transfer resistance increases because the interfacial contact between the hydrophobic electrode surface and aqueous electrolyte is not good. In this regard, we propose a method to obtain higher electrochemical performance based on improved interfacial properties by treating the electrode surface with oxygen plasma. The surface hydrophilization induced by the enriched oxygen functionalities was confirmed by the contact angle measurement. As a result, the degree of hydrophilization was easily adjusted by controlling the power and duration of the oxygen plasma treatment. As the electrolyte of the supercapacitor, PVA/H₃PO₄, which is a typical solid-state aqueous electrolyte, was used. Free-standing membranes of PVA/H₃PO₄ electrolyte were prepared and then pressed onto the electrode. The optimal condition was to perform oxygen plasma treatment for 5 seconds with a low power of 15 W, and the energy density of the supercapacitor increased by about 8%.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.2
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• pp.128-138
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• 2011

In this study, energy budget was estimated to produce an efficient artificial seed. And it needs to enhance fisheries productivity of sandfish, A. japonicus. In order to estimate energy budget of the sandfish, A. japonicus juvenile fed on nonriched Artemia nauplii (NA) and the enriched Artemia nauplii (EA), of sandfish were reared at constant condition of seawater temperature of natural temperature (NT) and heated temperature (HT). During the reared period, energy used by the reared juveniles were calculated from estimates of data on ingestion, growth, oxygen consumption, nitrogen excretion and energy content. Energy budget of NT-NA, NT-EA, HT-NA and HT-EA were represented as 100C=66.49G+21.28M+0.78F+1.44U, 100C=67.54G+21.40M+9.39F+1.67U, 100C=66.86G+22.66M+8.01F+2.47U and 100C=67.06G+22.96M+7.70F+2.28U. The assimilation efficiency estimated NT-NA, NT-EA, HT-NA and HTEA were represented as 87.78%, 88.94%, 89.52% and 90.02%. Gross growth efficiency estimated NT-NA, NT-EA, HT-NA and HT-EA were represented as 66.49%, 67.54%, 66.86% and 67.06%. Net growth efficiency estimated NT-NA, NT-EA, HT-NA and HT-EA were represented as 75.75%, 75.94%, 74.68% and 74.49%. In this results, two ways could be considered to produce an efficient artificial seed of sandfish. To hasten the growth of sandfish juvenile, heated seawater (HT) and enriched Artemia nauplii (EA) should be inputted to reared condition. And to increase the energy efficiency, natural seawater (NT) and enriched Artemia nauplii (EA) should be inputted to reared condition.

• Journal of Aquaculture
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• v.16 no.3
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• pp.159-164
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• 2003

Effect of the benthic echiurid Urechis unicinctus juveniles on the chemical characteristics of organically enriched sediment, as well as the individual survival rate and growth in various sediments, was investigated in this study to ascertain the effectiveness of U. unicinctus in the bioremediation of organically polluted sediment. The content of acid volatile sulfide (AVS) in the sediment of three coastal areas was 0.4±0.1 mg/gㆍdry sediment in Seonso, 0.1±0.01 mg/gㆍdry sediment in Myo-do, 0.02±0.01 mg/gㆍdry sediment in Dolsan-do, respectively. 500 juveniles with average body length of 1.2±0.3 mm were bred in these sediments. After 30 days, the AVS content of three places decreased to 0.29±0.3, 0.08±0.01 and 0.0l±0.01 mg/gㆍdry. After 60 days, the content was 0.23±0.03, 0.0l±0.01, 0.0l±0.01 mg/gㆍdry. The AVS content in the control (sediment from Seonso without juveniles) was 0.39±0.75 mg/gㆍdry sediment (after 30 days) and 0.45±0.01 mg/gㆍdry sediment (after 60 days). At the same time, the chemical oxygen demand (COD) and total ingition loss (TIL) of these sediments showed the same trend with that of AVS. Furthermore, 60 days later, the survival rate and growth of juveniles were 71.2%, 11.1±l.0 mm in Seonso, 89.8%, 12.0±1.3 mm in Myo-do and 81.6%, 11.9±1.9 mm in Dolsan-do. It was suggested that U. unicinctus can survive better in less polluted environment. Under different U. unicinctus juvenile density (100, 300, 500, 700, 900 individuals), after 60 days cultivation, the AVS content decreased from 0.4±0.1, 0.4±0.1, 0.4±0.3, 0.4±0.3, 0.4±0.3 mg/gㆍdry to 0.4±0.2, 0.3±0.2, 0.2±0.1, 0.2±0.1, 0.2±0.1 mg/gㆍdry. Therefore, the higher the density of juveniles, the greater the effect in improving the sediment. In comparison to different initial AVS concentration (0.40±0.01, 0.35±0.01, [I can't find a reference to this number above], 0.29±0.02, [I can't find a reference to this number above], 0.18±0.03, [I can't find a reference to this number above], 0.06±0.02 mg/gㆍdry sediment [I can't find a reference to this number above] and the control 0.0±0.0[I can't find a reference to this number above]), after 30 days cultivation with 500 juveniles, the AVS content was 0.29±0.03, 0.19±0.0, 0.15±0.01, 0.12±0.02, 0.05±0.0mg/gㆍdry and 0(control). After 60 days cultivation, the content was 0.23±0.03, 0.12±0.4, 0.10±0.01, 0.18±0.03, 0.06±0.02 mg/gㆍdry and 0 (control). Use % decrease in AVS content to state: The impact of U. unicinctus on the sediments was greater with higher concentrations of AVS. The results of this study indicate that U. unicinctus is effective in the biological treatment of sediments polluted by AVS and other organics.

• Journal of Ginseng Research
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• v.47 no.3
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• pp.366-375
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• 2023

Background: Ginseng contains three active components: ginsenosides, gintonin, and polysaccharides. After the separation of 1 of the 3 ingredient fractions, other fractions are usually discarded as waste. In this study, we developed a simple and effective method, called the ginpolin protocol, to separate gintonin-enriched fraction (GEF), ginseng polysaccharide fraction (GPF), and crude ginseng saponin fraction (cGSF). Methods: Dried ginseng (1 kg) was extracted using 70% ethanol (EtOH). The extract was water fractionated to obtain a water-insoluble precipitate (GEF). The upper layer after GEF separation was precipitated with 80% EtOH for GPF preparation, and the remaining upper layer was vacuum dried to obtain cGSF. Results: The yields of GEF, GPF, and cGSF were 14.8, 54.2, and 185.3 g, respectively, from 333 g EtOH extract. We quantified the active ingredients of 3 fractions: L-arginine, galacturonic acid, ginsenosides, glucuronic acid, lysophosphatidic acid (LPA), phosphatidic acid (PA), and polyphenols. The order of the LPA, PA, and polyphenol content was GEF > cGSF > GPF. The order of L-arginine and galacturonic acid was GPF >> GEF = cGSF. Interestingly, GEF contained a high amount of ginsenoside Rb1, whereas cGSF contained more ginsenoside Rg1. GEF and cGSF, but not GPF, induced intracellular [Ca²⁺]_i transient with antiplatelet activity. The order of antioxidant activity was GPF > GEF = cGSF. Immunological activities (related to nitric oxide production, phagocytosis, and IL-6 and TNF-α release) were, in order, GPF > GEF = cGSF. The neuroprotective ability (against reactive oxygen species) order was GEF > cGSP > GPF. Conclusion: We developed a novel ginpolin protocol to isolate 3 fractions in batches and determined that each fraction has distinct biological effects.

• Economic and Environmental Geology
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• v.30 no.6
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• pp.543-551
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• 1997

Poongjeon talc deposits is emplaced in dolomite and dolomitic limestone of the Cambro-Ordovician Samtaesan Formation. Ore in Poongjeon is low grade talc and the deposit has been known as the contact metasomatic or hydrothermal replacement type related to the intrusion of late Cretaceous granite in this area. X-ray diffraction, electron microprobe analysis, fluid inclusion and stable isotope analysis were utilized to examine the mineralogy of the ore and the origin of the ore fluid. The ore from Poongjeon mine mainly consists of talc and tremolite with minor amount of illite, vermiculite, smectite, and chlorite-vermiculite mixed layer. Occurrence of ore body indicates that the talc-tremolite ore was formed through the replacement by the $SiO_2$-rich hydrothermal fluid along the bedding and dike boundaries, or contact of amphibolite and basic dike with carbonate rocks. The temperature and pressure of the ore forming fluids at the time of the talc mineralization were estimated as $350^{\circ}C$ and 400 bar, respectively, based on the heating and freezing data of the fluid inclusions in quartz from talc-tremolite veins. During the talc-tremolite formation, fluids were divided into $CO_2$-enriched fluid and $CO_2$-poor fluid from $CO_2$ immiscibility (or effervescence). Oxygen isotope values (${\delta}^{18}O$) of the talc-tremolite fall within a range between 12.2 and 12.9‰. Hydrogen isotope values(${\delta}D$) of the ore range from -60 to -85‰ and $H_2O$ contents range from 2.0 to 3.4 wt.%. ${\delta}^{18}O$ and ${\delta}D$ values of talc ore indicate that the hydrothermal fluid involved in talc-tremolite formation was of igneous origin. Oxygen and hydrogen isotopic exchange between talc ore and the surface water was negligible after talc-tremolite ore formation.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.1-5
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• 2004

Tunable diode laser absorption spectroscopy was performed for analysis of the H$_2$$^{18}$ O/H$_2$$^{16}$ O isotope ratio of a water sample which was enriched by the membrane distillation method. In order to improve the signal-to-noise ratio, the wavelength modulation spectroscopic method was used with a lock-in amplifier. The fringe noise could be suppressed by using the FFT (Fast Fourier Transform) lowpass filter and the optimization of the modulation depth of the laser frequency. The maximum deviation of $\delta$-value was measured to be$\pm$4$\textperthousand$.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.233-239
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• 2017

Background: Nephrotoxicity is the major side effect in cisplatin chemotherapy. Previously, we reported that the ginsenosides Rk3 and Rh4 reduced cisplatin toxicity on porcine renal proximal epithelial tubular cells (LLC-PK1). Here, we aimed to evaluate the protective effect of ginsenosides Rk3 and Rh4 on kidney function and elucidate their antioxidant effect using in vitro and in vivo models of cisplatin-induced acute renal failure. Methods: An enriched mixture of ginsenosides Rk3 and Rh4 (KG-KH; 49.3% and 43.1%, respectively) was purified from sun ginseng (heat processed Panax ginseng). Cytotoxicity was induced by treatment of $20{\mu}M$ cisplatin to LLC-PK1 cells and rat model of acute renal failure was generated by single intraperitoneal injection of 5 mg/kg cisplatin. Protective effects were assessed by determining cell viability, reactive oxygen species generation, blood urea nitrogen, serum creatinine, antioxidant enzyme activity, and histopathological examination. Results: The in vitro assay demonstrated that KG-KH ($50{\mu}g/mL$) significantly increased cell viability (4.6-fold), superoxide dismutase activity (2.8-fold), and glutathione reductase activity (1.5-fold), but reduced reactive oxygen species generation (56%) compared to cisplatin control cells. KG-KH (6 mg/kg, per os) also significantly inhibited renal edema (87% kidney index) and dysfunction (71.4% blood urea nitrogen, 67.4% creatinine) compared to cisplatin control rats. Of note, KG-KH significantly recovered the kidney levels of catalase (1.2-fold) and superoxide dismutase (1.5-fold). Conclusion: Considering the oxidative injury as an early trigger of cisplatin nephrotoxicity, our findings suggest that ginsenosides Rk3 and Rh4 protect the kidney from cisplatin-induced oxidative injury and help to recover renal function by restoring intrinsic antioxidant defenses.

• Corrosion Science and Technology
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• v.5 no.4
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• pp.141-148
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• 2006

The chemical composition and the semiconducting properties of the passive films formed on Alloy 690 in various film formation conditions were investigated by XPS, photocurrent measurement, and Mott-Schottky analysis. The XPS and photocurrent spectra showed that the passive films formed on Alloy 690 in pH 8.5 buffer solution at ambient temperature, in air at $400^{\circ}C$, and in PWR condition comprise $Cr_2O_3$, $Cr(OH)_3$, ${\gamma}-Fe_2O_3$, NiO, and $Ni(OH)_2$. The thermally grown oxide in air and the passive film formed at high potential (0.3 $V_{SCE}$) in pH 8.5 buffer solution were highly Cr-enriched, whereas the films formed in PWR condition and that formed at low potential (-0.3 $V_{SCE}$) in pH 8.5 buffer solution showed relatively high Ni content and low Cr content. The Mott-Schottky plots exhibited n-type semiconductivity, inferring that the semiconducting properties of the passive films formed on Alloy 690 in various film formation conditions are dominated by Cr-substituted ${\gamma}-Fe_2O_3$. The donor density, i.e., concentration of oxygen vacancy, was measured to be $1.2{\times}10^{21}{\sim}4.6{\times}10^{21}cm^{-3}$ and lowered with increase in the Cr content in the passive film.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.149-157
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• 2004

In the present paper we studied experimentally fundamental optimization of oxygen enriched pyrolysis melting incinerator, Characteristics of this system was confirmed dealing with the gas flow and combustion properties for the inside secondary air injection. The experiment setup has a disposal rate of 30kg/hr which was measured by the inside temperature and gas. Along with above experiments, the three-dimensional computation was employed to analyse the combustion fluid dynamics and gas residence time. Equations for turbulence and heat - transmission as well as chemical reactions were solved by using common codes. The experimental combustion chamber was composed of staged combustion types structure for reducing NOx. Finally, it was verified that the control of the secondary air and air ratio of thermo stack were important. In the computational analysis, it showed reasonable agreement with the experimental results regarding the temperature and discharged gas concentration.