• Journal of Life Science
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• v.26 no.6
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• pp.640-645
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• 2016

Microglial cells are immediately activated in the central nervous system in response to a variety of neuronal environmental changes, such as injuries or inflammation. In addition to the modulation of the intrinsic immune response, a key role of microglial cells is the phagocytosis of dying cells and cellular debris. In this study, the inhibitory effects of epigallocatechine-3-gallate (EGCG), a most abundant and active polyphenol component of green tea, on lipopolysaccharide (LPS)-induced microglial activation are determined. EGCG dose dependently suppressed LPS-induced nitric oxide production and the expression of inducible nitric oxide synthase (iNOS) in BV-2 microglial cells. EGCG are potent LPS-induced inhibitors of several pro-inflammatory cytokine expressions, such as TNF-α and IL-1β, in microglial cells. Furthermore, EGCG generally inhibits the induction of LPS-mediated microglial activation and potently inhibits the phagocytosis of LPS-stimulated BV2 microglia. Although the conditioned media from LPS-stimulated BV-2 cells caused the SN4741 cell death, that from the conditioned media of EGCG pretreated BV-2 cells did not diminish the viability of SN4741 cells. These results suggest EGCG, a green tea polyphenol, could be a promising available molecule for the modulation of harmful microglial activation.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.57-67
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• 2012

In the design for piled rafts, the load capacity of the raft is in general ignored and the load capacities of pile are only considered for the estimation of the total load carrying capacity of the piled raft. The axial resistance of piled raft is offered by the raft and group piles acting on the same supporting ground soils. As a consequence, pile - soil - raft and pile - soil interactions, occurring by stress and displacement duplication with pile and raft loading conditions, acts as a key element in the design for piled rafts. In this study, a series of centrifuge model tests has been performed to compare the axial behavior of group pile and raft with that of a piled raft (having 16 component piles with an array of $4{\times}4$) at the stiff and soft clays. From the test results, it is observed that the interactions of piles, soil, and raft has little influences on the load capacities of piles and raft in piled rafts compared with the load capacities of group piles and raft at the same clay soil condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.225-233
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• 2016

This study examined how the level of competition in the banking industry affects the risk-seeking tendency of individual banks. In earlier studies, the NPL ratio was used as an indicator of the risk-seeking tendency, but this ratio has limits because it is an ex post indicator of the risk. Therefore, the asset risk was chosen as a new indicator of the risk-seeking tendency, which is an ex ante measure of the risk, and the data were analyzed. The results suggested that there is a negative correlation between the level of competition of the banking industry and the risk-seeking tendency. Interestingly, opposite results were obtained when the NPL ratio was applied as an indicator of risk-seeking tendency. Therefore, the correlation between the level of competition in the banking industry and the risk-seeking tendency depends on the indicator of the risk-seeking tendency. This means choosing the appropriate indicator is the key component leading to precise results. The asset risk is more consistent with the concept of risk-seeking tendency than the NPL ratio, and it is a more appropriate indicator considering that the asset risk is a relatively less affected indicator other than risk-seeking tendencies.

• Nutrition Research and Practice
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• v.12 no.2
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• pp.93-100
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• 2018

BACKGROUND/OBJECTIVE: Oxidative stress plays a key role in neuronal cell damage, which is associated with neurodegenerative disease. The aim of present study was to investigate the neuroprotective effects of perilla oil (PO) and its active component, alpha-linolenic acid (ALA), against hydrogen peroxide $(H_2O_2)$-induced oxidative stress in SH-SY5Y neuronal cells. MATERIALS/METHODS: The SH-SY5Y human neuroblastoma cells exposed to $250{\mu}M$ $H_2O_2$ for 24 h were treated with different concentrations of PO (25, 125, 250 and $500{\mu}g/mL$) and its major fatty acid, ALA (1, 2.5, 5 and $25{\mu}g/mL$). We examined the effects of PO and ALA on $H_2O_2$-induced cell viability, lactate dehydrogenase (LDH) release, and nuclear condensation. Moreover, we determined whether PO and ALA regulated the apoptosis-related protein expressions, such as cleaved-poly ADP ribose polymerase (PARP), cleaved caspase-9 and -3, BCL-2 and BAX. RESULTS: Treatment of $H_2O_2$ resulted in decreased cell viability, increased LDH release, and increase in the nuclei condensation as indicated by Hoechst 33342 staining. However, PO and ALA treatment significantly attenuated the neuronal cell death, indicating that PO and ALA potently blocked the $H_2O_2$-induced neuronal apoptosis. Furthermore, cleaved-PARP, cleaved caspase-9 and -3 activations were significantly decreased in the presence of PO and ALA, and the $H_2O_2$-induced up-regulated BAX/BCL-2 ratio was blocked after treatment with PO and ALA. CONCLUSIONS: PO and its main fatty acid, ALA, exerted the protective activity from neuronal oxidative stress induced by $H_2O_2$. They regulated apoptotic pathway in neuronal cell death by alleviation of BAX/BCL-2 ratio, and down-regulation of cleaved-PARP and cleaved caspase-9 and -3. Although further studies are required to verify the protective mechanisms of PO and ALA from neuronal damage, PO and ALA are the promising agent against oxidative stress-induced apoptotic neuronal cell death.

• Journal of Plant Biotechnology
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• v.41 no.1
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• pp.10-18
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• 2014

Seed oils (triacylglycerols) of plants are used as a source of essential fatty acids and nutrition for human. In addition, triacylglycerols have been used as industrial raw materials and biofuels. Triacylglycerols are mainly accumulated in seeds by complicated biochemical pathways. Fatty acids are synthesized in the plastids and transported into the endoplasmic reticulum for synthesizing triacylglycerols. It is known for a long time that biosynthesis of triacylglycerols is performed by a de novo synthesis, the Kennedy pathway. However recent studies have revealed that phosphatidylcholine, a major component of cell membrane, plays a central role for triacylglycerols biosynthesis. Phosphatidylcholine is a key regulator determining the relative proportions of unsaturated fatty acids in seeds. It may be a major carrier for the fluxes of fatty acids from the plastid to the endoplasmic reticulum. This finding further suggests that studies of the functions of enzymes involved in the fluxes of fatty acids from phosphatidylcholine to triacylglycerols elucidate the specialized subdomains in the endoplasmic reticulum for triacylglycerols biosynthesis.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.955-960
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• 2005

Resistance to metronidazole, a key component of therapies against Helicobacter pylori, is common in clinical isolates. Resistance generally requires inactivation of rdxA (HP0954), and sometimes also frxA (HP0642), two related nitroreductase genes. Here we studied the effect of resistance to metronidazole on fitness of the gastric pathogen H. pylori. The effect of metronidazole resistance for H. pylori in culture was assessed first by looking at colonies formed by freshly constructed mutant derivatives of H. pylori strain 26695. Mutations resulting in metronidazole resistance caused premature death of H.pylori in stationary phase, but had no significant effect on early exponential growth. The effect of nitroreductase deficiencies on fitness in vivo was tested by infecting C57BL/6 mice with 1:1 mixtures of SS1 wild type and its isogenic metronidazole resistant derivatives. Inactivation of rdxA caused an inability to colonize mice in SS1 H. pylori strain. Derivatives of a metronidazole resistant strain that survived better in stationary phase, although remaining metronidazole resistant, could again colonize mice. In conclusion, metronidazole resistance diminishes H. pylori's fitness, but their costs can be suppressed by additional mutation.

• Journal of Korean Society of Forest Science
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• v.90 no.6
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• pp.774-780
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• 2001

Aboveground carbon storage and increment of a 31-year-old pitch pine (Pinus rigida) stand were measured for five years (1997~2001) in the Jungbu Forest Experiment Station, Gyeonggi-do, Korea. The carbon concentration in each component of aboveground and soil depth decreased in the order of needle>branch>stembark>stemwood>forest floor>0-15cm soil depth>15-30cm soil depth. The carbon storage except for root carbon was 140,600kgC/ha and the tree accounted for 61%, soil 31% and forest floor 8% of the stand carbon storage. Due to high tree mortality by Fusarium subglutinans infection and spring drought in 2001, carbon increment except for 2001 data was 3,233kgC/ha/yr and was in the order of stemwood>branch>stembark>needle. Carbon storage and increment were attributed to stand density and site quality. Carbon storage and increment were higher in the high site quality than in the lower site quality plot on similar tree density. Also, the high tree density site on similar site quality showed more carbon storage and increment compared with the lower tree density. The results suggest that site quality and tree density are a key factor determining carbon storage and increment in this pitch pine stand.

• Korean Journal of Optics and Photonics
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• v.30 no.5
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• pp.187-192
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• 2019

In this paper a pump combiner, a key component of a high-power fiber laser, was fabricated, and its output characteristics measured using a high-power performance measuring instrument. The $(18+1){\times}1$ pump combiner consists of an optical-fiber bundle of one signal fiber and 18 pump fibers, an output optical fiber, and housing. The signal and output fibers were fabricated using polarization-maintaining optical fiber. By measuring the loss of signal light along the tapering length of the optical-fiber bundle, the tapering length was optimized to 18 mm. Signal-light insertion loss, pump-light transmittance, and polarization extinction ratio of the fabricated $(18+1){\times}1$ pump combiner were measured as 6.5%, 98.07%, and 18.0 dB respectively. The temperature distribution of the pump combiner, at a high power of 2 kW using 18 pump laser diodes, was measured and analyzed using a thermal-imaging camera.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.173-181
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• 2016

Skin basement membrane (BM) is a specialized structure that binds dermis and epidermis of the skin and plays an important role in maintaining skin structure. Structural change and destruction of BM is reported to appear due to UV exposure and aging, which may contribute to skin aging including wrinkle formation and a decrease in elasticity of the skin. One of the key components of the BM is laminin-332 (LN-332), and is a major contributor to epidermal-dermal attachment. In this study, we elucidated the effects of Meladrium firmum hexane fraction (MFHF) on LN-332 expression in HaCaT, a human keratinocyte cell line. Quantitative real-time PCR (RT-PCR) and immunoblot analysis revealed that MFHF induced upregulation of LN-332 gene and protein expression. Next, cells were treated with p38 MAPK inhibitor (SB202190) prior to MFHF treatment to analyze the signaling pathway contributing to LN-332 expression. The mRNA and protein levels of LN-332 expression were suppressed completely by pretreatment with p38 MAPK inhibitor. Furthermore, MFHF also increased the mRNA level of collagen type VII and integrin ${\alpha}6$ of skin BM component. These results collectively suggest that MFHF may have potential as an effective agent to stimulate the synthesis of BM components, and could be used to improve phenomenon of skin aging ascribed to the structural and functional impairments of BM in aged human skin.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.913-921
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• 2021

Objective : Accurate measurement of T1 slope (a component of T1s minus cervical lordosis [CL]) is often constrained by anatomical limitations. In this situation, efforts should be made to find the exact meaning of T1s-CL and whether there are any alternatives to it. Methods : We enrolled 117 patients who received two-level anterior cervical discectomy and fusion (ACDF). Occipital slope, C2 slope (C2s), C7 slope (C7s), T1, O-C2 angle (O-C2A), C2-7 angle (C2-7A), O-C7 angle (O-C7A), T1s-CL, C7-T1 angle (C7-T1A), and C2-7 sagittal vertical axis were measured. We determined 16° (T1s-CL) as the reference point for dividing subjects into the mismatch group and the balance group, and a comparative analysis was performed. Results : The mean value of C7-T1A was constantly maintained within 2.6° peri-operatively. In addition, C2s and T1s-CL showed the same absolute change (Δ|0.8|°). The mean values of T1s-CL of the mismatch and balance groups were 23.0° and 7.6°, respectively. The five factors with the largest differences between the two groups were as follows : C2s (Δ13.3°), T1s-CL (Δ15.4°), O-C2A (Δ8.7°), C2-7A (Δ14.7°), and segmental angle (Δ7.9°) before surgery. Only four factors showed statistically significant change between the two groups after ACDF : T1s-CL (Δ4.0° vs. Δ0.2°), C2s (Δ3.2° vs. Δ0.7°), O-C2A (Δ2.6° vs. Δ1.3°), C2-7A (Δ6.3° vs. Δ1.3°). A very strong correlation between T1s-CL and C2s was also found (r=|0.88-0.96|). Conclusion : C2s itself may be the essential key to represent T1s-CL. The amounts and directions of change of these two factors (T1s-CL and C2s) were also almost identical. The above phenomenon was re-confirmed once again through the correlation analysis.