• The Korean Journal of Zoology
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• v.28 no.4
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• pp.227-236
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• 1985

In an attempt to make a scrutiny into a mechanism for the formation of quaternary structure of LDH isozymes, male mice were intraperitoneally exposed to a wide range of tetrodotoxin concentration and the changes in relative percentage of the five isozymes were monitored by electrophoresis and subsequent densitometry. The observations that a conspicuous increase of the $H_4$ isozyme was demonstrated in nearly all brain tissues, that the $M_4$ isozyme of skeletal muscle tissue was slightly increased while the $M_3H$ and $M_2H_2$ isozymes were decreased, that the M/H ratio was strikingly reduced in heart tissue and that assembly of $H_4$ isozyme was revealed in liver tissue although its rate was extremely low suggest that new intracellular ionic environment established by compulsory change in Donnan equilibrium could alter the LDH isozyme distribution. The reduction of assembly of $M_3H$ isozyme found in mouse tissues exposed to tetrodotoxin also seems to suggest that the subunit combination of 3M+H is very unfavorable in an intracellular environment deviated from its accustomed one. It was reaffirmed that there might occur TTX-insensitive sodium channels in plasma membrane.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.346-346
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• 2012

We investigated electrical and optical properties and chemical states of amorphous In-Ga-Zn-O (a-IGZO) thin films deposited at different substrate temperatures (from room temperature to $300^{\circ}C$). a-IGZO thin films were fabricated by radio frequency magnetron sputtering using $In_2O_3$ : $Ga_2O_3$ : ZnO = 1 : 1 : 1 target, and their electrical and optical properties and chemical states were investigated by Hall-measurement, UV-visible spectroscopy and x-ray photoelectron spectroscopy (XPS), respectively. The data showed that as substrate temperature increased, carrier concentration increased, but mobility, conductivity, transmittance in the shorter wavelength region (>350 nm), and the Tauc-plot-estimated optical bandgap decreased. XPS data indicated that the intensity of In 3d peak compared to Ga 3d peak increased but the intensity of Zn 3d peak compared to Ga 3d decreased, and that, from the deconvoluted O 1s peak, defects or oxygen vacancies and non-quaternary contents increased as the temperature increased. The relative intensity changes of the In, Zn, and O 1s sub-component are suggested to explain the changes in electrical and optical properties.

• Reproductive and Developmental Biology
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• v.33 no.4
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• pp.229-236
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• 2009

The glycoprotein hormone family represents a class of heterodimers, that includes the placental hormone equine chorionic gonadotropin (eCG) and the anterior pituitary hormones- follitropin (FSH), lutropin (LH), and thyrotropin (TSH). The 4 hormones are heterodimers, with a common $\alpha$-subunit and unique $\beta$-subunits. eCG is the most heavily glycosylated of the known pituitary and placental glycoprotein hormones. Recent observations using single chain glycoprotein hormone analogs in which, the $\beta$-and $\alpha$-subunits are linked, implied that heterodimeric-like quaternary configuration is not a prerequisite for receptor/signal transduction. To study the function and signal transduction of tethered rec-eCG, a single chain eCG molecule was constructed and rec-eCG protein was produced. Molecular mass of the single chain is about 45 kDa. All mice were ovulated by tethered rec-eCG treatment. The dual activity of tethered rec-eCG was determined in receptor cell lines of nonequid species; in fact, this dual activity was proven in species other than horse. Tethered rec-eCG in equids does not bind to FSH receptors, suggesting that eCG is primarily an LH-like hormone in the horse. Taken together, these data suggest that tethered rec-eCG has dual activity in nonequid species in vitro. However, it has only LH-like activity in equid species in vitro.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.639-642
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• 2006

This study aimed to identify effective washing and sanitation programs to minimize the contamination of cooked rice by B. cereus. As such, the effectiveness of five sanitizers, including QAC, alcohol, chlorine, CaO, and $H_2O_2$, was evaluated in relation to the survivability of B. cereus spores in cooked rice and resulting sensory properties of the rice. The water-treated cooked rice showed remaining B. cereus spores at 1.09 $log_{10}CFU/g$. In contrast, treatment with the minimum inhibitory concentrations of the sanitizers, such as 200 ppm of QAC, 50% of alcohol, 100 ppm of chlorine, 650 ppm of CaO, and 500 ppm of $H_2O_2$, destroyed all the spores in the cooked rice below a non-detection limit (ND< 0.15 CFU/g). The sensory properties of the sanitizer-treated (1,000 ppm of $H_2O_2$, 100 ppm of chlorine, and 800 ppm of CaO) cooked rice did not differ significantly from those of the water-treated cooked rice. As a result, 500 ppm of $H_2O_2$, 650 ppm of CaO, and 100 ppm of chlorine were found to effectively eliminate B. cereus spores in rice while cooking.

• Journal of Ocean Engineering and Technology
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• v.26 no.3
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• pp.26-32
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• 2012

Recently, concrete using multicomponent blended cement has been required to increase the freeze-thaw and sulfate resistances of concrete structures exposed to a marine environment. Thus, the purpose of this study was to propose the use of concrete containing multicomponent blended cement as one of the alternatives for concrete structures exposed to a marine environment. For this purpose, batches of concrete containing ordinary portland cement (OPC), binary blended cement (OPC-G, G: ground granulated blast slag), ternary blended cement (OPC-GF, F: fly ash), and quaternary blended cement (OPC-GFM, M: mata-kaolin) were made using a water-binder ratio of 50%. Then, the durability levels, including thesulfate and freeze-thaw resistances, were estimated for concrete samples containing OPC, OPC-G, OPC-GF, and OPC-GFM. It was observed from the tests that the durability levels of the concrete samples containing OPC-G and OPC-GF were found to be much better than that of the concrete containing OPC. The optimum mixing proportions were a40% replacement ratio of ground granulated blast slag for the binary blended cement and a30% replacement ratio of ground granulated blast slag and 10% fly ash for the ternary blended cement.

• Biomedical Science Letters
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• v.16 no.3
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• pp.133-138
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• 2010

Despite of the increasing importance of environmental mycobacteria, detection and identification of mycobacteria from environmental sources including water have been fraught with technical difficulties. Although, several protocols to optiruize isolation of mycobacteria from water sources have been reported, standard method has not yet been established. In this study, usefulness of cetylpyridinium chloride (CPC), a cationic quaternary ammonium compound, for the isolation of environmental mycobacteria from diverse water samples was evaluated. For this, water samples from diverse water sources such as effluent water, lake water, and underground water were collected, treated with diverse concentrations of CPC, and plated on the solid agar plates. Subsequently individual colonies grown on the plates were sequence analyzed for identification of each colony. In brief, the results from this study showed that the growth of mycobacteria was enhanced by use of CPC as a pre-treatment reagent to water samples by inhibiting growth of other non-mycobacteria in water. In fact, the effect of CPC to decontaminate non-mycobacteria for isolation of mycobacteria was better than 1~4% of NaOH, which is a routinely used decontaminating reagent widely employed for culturing mycobactera from sputum specimens. Therefore, the results from this study seems to support that the CPC pre-treatment may be useful for isolation of mycobacteria from diverse sources including clinical specimens which are often contaminated with other bacteria.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.85-97
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• 2004

Weathering of hornfels pebble in the marine terrace deposits, Yangnam-Myon, Gyeongju was investigated by X-ray diffraction, scanning electron microscopy, and chemical analysis. In the early stage of weathering, only plagioclase was leached leaving pores. With progress of weathering, biotite and chlorite were tranformed to hydrobiotite and chlorite-vermiculite, respectively. Quartz, K-feldspar, and muscovite were not altered. Thickness of weathering rinds and their mineralogical characteristics were different between terraces of different elevations. In the lower second terrace, the weathering of pebble was dominated by the decomposition of plagioclase, while in the upper third terrace, weathering was characterized by the transformation of biotite and chlorite with precipitation of halloysite from the weathering of plagioclase. Thickness of weathering rind and weathering products were varied even within the same terrace deposit probably due to local variation of drainage conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.334-334
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• 2012

Transparent oxide semiconductors have recently attracted much attention as channel layer materials due to advantageous electrical and optical characteristics such as high mobility, high stability, and good transparency. In addition, transparent oxide semiconductor can be fabricated at low temperature with a low production cost and it permits highly uniform devices such as large area displays. A variety of thin film transistors (TFTs) have been studied including ZnO, InZnO, and InGaZnO as the channel layer. Recently, there are many studies for substitution of Ga in InGaZnO TFTs due to their problem, such as stability of devices. In this work, new quaternary compound materials, tantalum-indium-tin oxide (TaInSnO) thin films were fabricated by using co-sputtering and used for the active channel layer in thin film transistors (TFTs). We deposited TaInSnO films in a mixed gas (O2+Ar) atmosphere by co-sputtering from Ta and ITO targets, respectively. The electric characteristics of TaInSnO TFTs and thin films were investigated according to the RF power applied to the $Ta_2O_5$ target. The addition of Ta elements could suppress the formation of oxygen vacancies because of the stronger oxidation tendency of Ta relative to that of In or Sn. Therefore the free carrier density decreased with increasing RF power of $Ta_2O_5$ in TaInSnO thin film. The optimized characteristics of TaInSnO TFT showed an on/off current ratio of $1.4{\times}108$, a threshold voltage of 2.91 V, a field-effect mobility of 2.37 cm2/Vs, and a subthreshold swing of 0.48 V/dec.

• Membrane Journal
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• v.13 no.1
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• pp.54-63
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• 2003

The Preparation and electrochemical characterization of anion-exchange membranes containing pyridinium groups were performed. As a result, the pyridinium membranes showed good electrochemical properties, comparable to those of the commercial membranes, with electrical resistance of less than $3.0 {\Xi}cm^2$ in a 0.5 mol $dm^{-3}$ NaCl and high ionic permselectivity (the transport number of $Cl^-$ ions being 0.97). Moreover, water splitting in the membranes containing pyridinium group was about two or three order of magnitude lower than those in the commercial membranes (ｅ.ｇ. AM-1, Tokuyama Crop., Japan) at the same current density because the resonance effedt in the quaternary aromatic pyridinium group contributed to their molecular stability. In addition, the electrodialytic properties of the pyridinium membranes were evaluated in a semi-pilot scale.

• Geophysics and Geophysical Exploration
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• v.19 no.2
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• pp.97-104
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• 2016

Small to large earthquakes have been reported in Gyeongju and its vicinity in southeast Korea during historical period as well as instrumental observation period. We identified and located more than 300 earthquakes that occurred between January 2010 and December 2014 in a $20km{\times}30km$ area, but were unreported because of their small magnitudes. We used the Joint Hypocenter Determination (JHD) method to minimize the influence of the differences between the actual earth structure and 1-D velocity model for earthquake locations. The potential relationship between the previously reported Quaternary faults and the earthquake hypocenters was investigated. Many micro-earthquakes were found to be located in the southern segment of the Yeonil Tectonic Line, the Seokup fault, and the Waup basin boundary faults.