• Animal cells and systems
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• v.9 no.1
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• pp.19-25
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• 2005

This study was conducted to determine the effect of dietary salt on the synthesis of glucocorticoids in the adrenal cortex of mice. Mice had ad libitum access to 3% sodium chloride as the only drinking fluid (high salt diet) for either 4 days or 4 weeks. Adrenocortical expression of cytochrome P450 11beta-hydroxylase, a major regulatory enzyme in the biosynthesis of glucocorticoids, was examined by immunohistochemistry and western blot analysis. Ultrastructure of adrenocortical cell and plasma level of corticosterone were analyzed as well. Size and density of lipid droplets in the cortical cell were increased by high salt diet. Four days of high salt diet decreased P450 11beta-hydroxylase in the adrenal cortex, but 4 weeks increased it. Plasma level of corticosterone changed in parallel with the Cortical level of P450 11 beta-hydroxylase. These results suggest that high salt diet may modulate the biosynthesis of glucocorticoids, at least partly, via regulating the expression of P450 11beta-hydroxylase in adrenocortical cells.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.775-780
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• 2006

Mechanical and electrical performance of anode-supported SOFC single cells were analyzed after thermal cyclic operation. The experiments of thermal cyclic cell-operation were carried out four times and performance of each cell was measured at different temperatures of 650, 700, and $750^{\circ}C$, respectively. As increasing the number of thermal cycle test, single cells showed poor I-V characteristics and lower 4-point bending strength. The anode polarization was also measured by AC-impedance analysis. The observation of the microstructure of the anodes in single cells proved that the average particle size of Ni decreased and the porosity of anode increased. It is thought that the thermal cycle caused the degradation of performance of single cells by reducing the density of three-phase boundary region.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.22-27
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• 2009

Target design study to improve the quality of an accelerated proton beam from the interaction of a high-intensity short pulse laser with an overdense plasma slab has been accomplished by using a two-dimensional, fully electromagnetic and relativistic particle-in-cell (PIC) simulation. The target consists of a thin core part and a thick peripheral part of equivalent plasma densities, while the ratio of the radius of the core part to the laser spot size, and the position of the peripheral part relative to the fixed core part were varied. The positive effects of this core-peripheral target structure could be expected from the knowledge of the typical target normal sheath acceleration (TNSA) mechanism in a laser-plasma interaction, and were apparently evidenced from the comparison with the case of a conventional simple planar target and the case of the transversal size reduction of the simple planar target. Improvements of the beam qualities including the collimation, the forward directionality, and the beam divergence were verified by detailed analysis of relativistic momentum, angular directionality, and the spatial density map of the accelerated protons.

• Membrane Journal
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• v.2 no.2
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• pp.122-128
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• 1992

A study on the citric acid production was performed in various size dual hollow fiber bioreactors with immobilized Aspergillus niger (KCTC 1232). The final dry cell mass density reached 300g/l based on the space volume available for cell growth. Under air and oxygen aeration the volumethe productivity reached 0.63 and 1.02g/l.h, which cormsponded to 10 and 16 fold over those of batch fermentation, respectively. The initial pH of the medium was a critical factor and the lower value resulted in higher citric acid yield. The increase in the feeding rate of medium or the number of reactor unit resulted in the improvement of the productivity due to higher consumption rate of substrate.

• Journal of Powder Materials
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• v.18 no.3
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• pp.256-261
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• 2011

In order to make a $Cu_2ZnSnSe_4$ (CZTSe) sputtering target sintered for solar cell application, synthesis of CZTSe compound by solid state reaction of Cu, Zn, Sn and Se mixed powders and effects of ball milling condition on sinterability such as ball size, combination of ball size, ball milling time and sintering temperature, was investigated. As a result of this research, sintering at $500^{\circ}C$ after ball milling using mixed balls of 1 mm and 3 mm for 72 hours was the optimum condition to synthesis near stoichiometric composition of $Cu_2ZnSnSe_4$ and to prepare sintered pellet with high density relatively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.129-129
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• 2013

Nanometal alloy catalysts have been found to significantly increase catalytic efficiency, compared to the monometallic counterparts. This enhancement can be attributed to various alloying effects: i) the existence of uniquemixed-metal surface sites [the so called ensemble (geometric) effect]; ii) electronic state changes due to metal-metal interactions [the so called ligand (electronic) effect]; and iii) strain caused by lattice mismatch between the alloy components [the socalled strain effect]. In addition, the presence of low-coordination surface atoms and preferential exposure of specific facets [(111), (100), (110)] in association with the size and shape of nanoparticle catalysts [the so called shape-size-facet effect] can be another important factor for modifying the catalytic activity. However, mechanisms underlying the alloying effect still remain unclear owing to the difficulty of direct characterization. Computational approaches, particularly the prediction using first-principles density functional theory (DFT), can be a powerful and flexible alternative for unraveling the role of alloying effects in catalysis since those can give us quantitative insights into the catalytic systems. In this talk, I will present the underlying principles (such as atomic arrangement, facet, local strain, ligand interaction, and effective atomic coordination number at the surface) that govern catalytic reactions occurring on Pd-based alloys using the first-principles calculations. This work highlights the importance of knowing how to properly tailor the surface reactivity of alloy catalysts for achieving high catalytic performance.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.6-11
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• 2018

As embedded memory technology evolves, the traditional Static Random Access Memory (SRAM) technology has reached the end of development. For deepening the manufacturing process technology, the next generation memory technology is highly required because of the exponentially increasing leakage current of SRAM. Non-volatile memories such as STT-MRAM (Spin Torque Transfer Magnetic Random Access Memory), PCM (Phase Change Memory) are good candidates for replacing SRAM technology in embedded memory systems. They have many advanced characteristics in the perspective of power consumption, leakage power, size (density) and latency. Nonetheless, nonvolatile memories have two major problems that hinder their use it the next-generation memory. First, the lifetime of the nonvolatile memory cell is limited by the number of write operations. Next, the write operation consumes more latency and power than the same size of the read operation.These disadvantages can be solved using the compiler. The disadvantage of non-volatile memory is in write operations. Therefore, when the compiler decides the layout of the data, it is solved by optimizing the write operation to allocate a lot of data to the SRAM. This study provides insights into how these compiler and architectural designs can be developed.

• BMB Reports
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• v.50 no.2
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• pp.71-78
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• 2017

The Hippo signaling pathway plays an essential role in adult-tissue homeostasis and organ-size control. In Drosophila and vertebrates, it consists of a highly conserved kinase cascade, which involves MST and Lats that negatively regulate the activity of the downstream transcription coactivators, YAP and TAZ. By interacting with TEADs and other transcription factors, they mediate both proliferative and antiapoptotic gene expression and thus regulate tissue repair and regeneration. Dysregulation or mutation of the Hippo pathway is linked to tumorigenesis and cancer development. Recent studies have uncovered multiple upstream inputs, including cell density, mechanical stress, G-protein-coupled receptor (GPCR) signaling, and nutrients, that modulate Hippo pathway activity. This review focuses on the role of the Hippo pathway as effector of these biophysical cues and its potential implications in tissue homeostasis and cancer.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.416-420
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• 1990

Ultrastructural and anatomical features of the leaf were studied in Panax ginseng C.A. Meyer(ginseng). The ginseng leaf poorly developed palisade tissue and the size of mesophyll cell was larger and the chloroplast density was lower than that of Glycine max (soyben). Ginseng chloroplast was filled with highly stacked grana and condensely-arrayed thylakoid, so the stroma space was hardly absorbed. However, ginseng mesophyll tissue and chloroplast array did not reduce light energy entering the mesophyll chloroplast, and the high LHCP/CP ratio of ginseng thylakoid resulted in the absorption of excess photon. It is reasonable to assume that 1O1-photogenearation by excess light energy partially resulted from the anatomical and ultrastructural characteristics of the ginseng leaf.

• Journal of the Korean institute of surface engineering
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• v.24 no.3
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• pp.162-168
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• 1991

Gas diffusion and electrolyte penetration in wetproofed gas diffusion electrodes were studied using layers of PTFE- bonded carbon. Minor variations in fabrication and testing procedures resulted in very large variations in catalyst layer wetting characteristics and permiability for reaction gas. By controlling the pore size of gas diffusion electrode carefully by varing the PTFE contents, baking temperature, baking time and ammonium bicarbonate as additive, the primary pore was decreased and the secondary pore was increased and so more reaction gas through the primary pore could be reacted at catalyst agglomertes in the secondary pore. And the cathode current density was increased to more than 400mA.$\textrm{cm}^2$ and Tafel slope value was decreased to lower than 110mA/decade.