• Journal of Microbiology and Biotechnology
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• v.1 no.1
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• pp.37-44
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• 1991

A shuttle promoter-probe vector, pEB203, was derived from pBR322, pPL703 and pUB110. Using the vector, a useful DNA fragment, 319 bp EcoRI fragment, having strong promoter activity has been cloned from Bacillus subtills chromosomal DNA. Selection was based on chloramphenicol resistance which is dependent upon the introduction of DNA fragments allowing expression of a chloramphenicol acetyl transferase gene. The nucleotide sequence of the 319 bp fragment has been determined and the putative -35 and -10 region, ribosome binding site, and ATG initiation codon were observed. This promoter was named EB promoter and the resultant plasmid which can be used as an expression vector was named pEBP313. The crystal protein gene from B. thuringiensis subsp. kurstaki HD-73 was cloned downstream from the EB promoter without its own promoter. When the resultant plasmid, pBT313, was introduced into Escherichia coli and B. subtilis, efficient synthesis of crystal protein was observed in both cells, and the cp gene expression in B. subtilis begins early in the vegetative phase. The cell extracts from both clones were toxic to Hyphantria cunea larvae.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.297-298
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• 2005

We have fabricated twisted nematic (TN) liquid crystal cells doped by carbon nanotubes (CNTs) with different CNT wt. %. With a minute amount doping, multi-walled CNTs did not perturb the liquid crystal orientations at the off- and on-state. The hysteresis studies of voltage-dependent capacitance (V-C) under the influence of electric field generated by ac and dc voltage show that the residual do, which is tightly related to image sticking problem in liquid crystal displays, is greatly reduced due to ion trapping by CNTs. Also, the V-C hysteresis shows dependency of capacitance on concentration of multi-walled CNTs.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.88-93
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• 2008

The bulk-heterojunction polymer solar cell based on regioregular P3HT (poly(3-hexylthiophene)) and PCBM (methanofullerene [6,6]-phenyl $C_{61}$-butyric acid methyl ester) was fabricated. Annealing effects on the crystal structure of polymer-fullerene blends as well as the UV-VIS electronic absorption spectroscopy were investigated. The correlation between the crystal organization of bulk-heterojunction film and the power conversion efficiency of solar cell was studied. Resultantly, the polymer solar cell annealed on $150^{\circ}C$ for 30 min, showed both the enhanced molecular interactions and the optimized crystal structure and displayed the power conversion efficiency of 3.2 %.

• Medical Lasers
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• v.10 no.2
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• pp.82-89
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• 2021

Background and Objectives Due to changes in diet and lifestyle, the number of obese people worldwide is steadily increasing. Obesity has an adverse effect on a healthy life, so it needs treatment and improvement. Research related to this is continuously being conducted. Materials and Methods The laser system to compact designed using 808 nm laser diode and Neodymium Yttrium orthovanadate generates a 1064 nm wavelength, the periodically polarized nonlinear crystal pumping laser beam. The pulsed 1064 nm wavelength beam passing through the AO Q-switch is used as the pumping light of the nonlinear optical crystal and is irradiated to the periodic polarized nonlinear optical crystal with a quasi-phase matching period. Nonlinear optical crystals use an oven to control the temperature to generate the desired 1980 nm and 2300 nm wavelengths. Results The 1980 nm and 2300 nm wavelengths generated by temperature control of nonlinear optical crystals are effective for lipolysis. A fiber catheter was used so that the laser could be directly irradiated to the fat cells. In particular, the new wavelength (1980 nm, 2300 nm) can increase the fat reduction effect with low energy (1.3 W). When a laser with a combination wavelength of 1980 nm and 2300 nm was used, an average lipolysis effect of 20% was obtained. Conclusion A mid-infrared lipolysis laser system with excellent absorption of fat and water has been developed. We conducted a princlinical study to confirm the efficacy and safety of the lipolysis laser system, and obtained good results for lipolysis with low energy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.878-885
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• 2020

Previously, we reported that globefish Takifugu obscurus homogenate suppresses the growth of human colorectal cancer cells. To extend the applications of globefish homogenate, we investigated its cytotoxic effects on human breast cancer cells. To assess the effects of globefish homogenate on growth of MCF (Michigan Cancer Foundation)-7 human breast cancer cells, cell proliferation and colony formation assays were performed using the cell counting and Crystal Violet staining methods. The 50% inhibitory concentration (IC50) of globefish homogenate on MCF-7 cell proliferation was calculated from the sigmoidal dose-response curve. The colony formation assay demonstrated that MCF-7 cells treated with globefish homogenate formed up to 80% fewer colonies than control MCF-7 cells. Treatment with globefish homogenate markedly suppressed the growth of MCF-7 cells in a dose-dependent manner. The sensitivity of the cells to globefish homogenate was determined by calculating the IC50; in this case, the IC50 was 210 ㎍/mL. Furthermore, significant downregulation of Cyclin D1 expression, along with phospho-Akt and total Akt levels, was observed in MCF-7 cells treated with globefish homogenate. This study demonstrates that treatment with globefish homogenate inhibits the proliferation of MCF-7 human breast cancer cells by downregulating the expression of phosphor-Akt, total Akt, and Cyclin D1 proteins.

• Journal of Sensor Science and Technology
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• v.9 no.1
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• pp.70-75
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• 2000

The recycled single crystal silicon wafers have been fabricated into solar cells. It can be a solution for the high cost in materials for solar cells and recycling of materials. So, p-type (100) single crystal silicon wafers with high resistivity of $10-14\;{\Omega}cm$ and the thickness of $650\;{\mu}m$ were used for the fabrication of solar cells. Optimistic conditions of formation of back surface field, surface texturing and anti-reflection coating were studied for getting high efficiency. In addition, thickness variation of solar cell was also studied for increase of efficiency. As a result, the solar cell with efficiency of 10% with a curve fill factor of 0.53 was fabricated with the wafers which have the area of $4\;cm^2$ and thickness of $300\;{\mu}m$. According to above results, recycling possibility of wasted wafers to single crystal silicon solar cells was confirmed.

• Analytical Science and Technology
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• v.16 no.5
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• pp.375-390
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• 2003

A single crystal of fully indium-exchanged zeolite A (In-A) was brought into contact with antimony in a fine Pyrex capillary at $350^{\circ}C$ for 6 days. The reaction was monitored by electron-probe X-ray microanalysis (EPXMA). The crystal structure of antimony-sorbed indium-exchanged zeolite A has been determined by single-crystal X-ray diffraction techniques at $21^{\circ}C$ in the cubic space group Pm ${\bar{3}}m$. The crystal structure of $In_8Si_{12}Al_{12}O_{48}{\cdot}(In)_{1.35}(Sb)_{0.7}$ ($a=12.111(2){{\AA}}$, $R_1=0.071$, and $R_2=0.067$) has 8 indium cations, 1.35 indium atoms, and 0.7 antimony atoms per unit cell. Unit cell 1 ($In_8-A{\cdot}In$, 65% of unit cells) contain the $(In_5)^{8+}$ cluster. In unit cell 2 ($In_8-A{\cdot}(In)_2(Sb)_2$, 35% of unit cells), two $(In_3)^{2+}$ cluster and one $(In_3Sb_2)^{7+}$ cluster are found in the large cavity.

• Current Photovoltaic Research
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• v.11 no.1
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• pp.18-26
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• 2023

Tin perovskite solar cells have attracted a lot of attention due to their potential to address the toxicity of lead, which is the biggest barrier to commercialization of perovskite solar cells. Unlike other lead-free perovskite, tin perovskite have a direct bandgap, which is suitable for use as light harvesting, and relatively good stability, which has led to a lot of attention. Since the first tin perovskite solar cell was reported in 2014, it has achieved an impressive power conversion efficiency of 14.81%. However, this efficiency is still low compared to that of lead perovskite solar cells, and the stability of tin perovskite solar cells is also an issue that needs to be addressed. In this review, we will discuss the basic properties of the tin atom in comparison to the lead atom, and then discuss the crystal structure, phase transition, and basic properties of tin perovskite. We will then discuss the advantages, applications, challenges, and strategies of tin perovskite, In particular, we will focus on how to prevent the oxidation of tin, which is arguably the biggest challenge for using tin perovskite solar cells. At the end, we summarize the key factors that need to be addressed for higher efficiency and stability, emphasizing what is needed to commercialize tin perovskite solar cells.

• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.223-229
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• 1997

A source code is developed on the basis of Berreman's 4$\times$4 matrix formalism for the analysis of polarization transmission characteristics of twisted nematic liquid crystal display. By using the program, the polarization transmission characteristics of liquid crystal cells and polarizers are analyzed. For a normally white twisted nematic liquid crystal cell, we obtained a family of iso-contrast contours which helps to understand the viewing angle characteristics of the liquid crystal display device by using the cell. The program also help us to understand the variation of the degree of polarization as well as the deviation of the state of polarization of the light transmitted through the polarizer commonly used in the LCD according to the change in incidence angle. This result suggests the contrast of the images appearing on the LCD can be limited by the characteristics of the polarizer in addition to the liquid crystal cell.

• Molecules and Cells
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• v.39 no.3
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• pp.195-203
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• 2016

Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions ($Cu^+$ and $Cu^{2+}$), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped $Cu_2O$ and CuO crystals were prepared to test the role of the two different ions, $Cu^+$ and $Cu^{2+}$, respectively. The $Cu_2O$ crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The $Cu_2O$ crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. $Cu_2O$ crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit $Cu_2O$-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of $Cu^+$ ions in the vascular system, where $Cu^+$ induces autophagy while $Cu^{2+}$ has no detected effect.