• Journal of Life Science
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• v.30 no.4
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• pp.402-409
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• 2020

Nervous necrosis virus (NNV) contains a bi-segmented viral genome, RNA1 (3.4 kb, RdRp), and RNA2 (1.4 kb, capsid protein) in a small particle (25 nm). Despite its extremely compact size, NNV has caused serious damage by infecting approximately 120 fish species worldwide since it was first reported in the late 1980s. In order to minimize the damage caused by NNV infection and develop effective vaccines, it is necessary to understand the intra cellular signaling system according to NNV infection. NNV infection induces cell cycle arrest at the G1 phase via the p53-dependent pathway to use the cellular system for its replication. Otherwise, host cells recognize NNV infection through the RIG-1-like receptor (RLR) signaling pathway to control the virus and infected cells, and then ISGs required for antiviral action are activated via the IFN signaling pathway. Moreover, apoptosis of infected cells is triggered by the unfolded protein response (UPR) through ER stress and mitochondria-mediated cell death. Cell signaling studies on the NNV infection mechanisms are still at an early stage and many pathways have yet to be identified. Understanding the various disease-specific cellular signaling systems associated with NNV infection is essential for rapid and accurate diagnosis and vaccine development.

• Journal of Life Science
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• v.25 no.1
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• pp.93-100
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• 2015

Pachymic acid (PA) is a lanostane-type triterpenoid derived from the Poria cocos mushroom. Several beneficial biological features of PA provide medicine with a wide variety of valuable effects, such as anticancer and anti-inflammatory activity; it also has antioxidant effects against oxidative stress. Nonetheless, the biological properties and mechanisms that produce this anti-cancer action of PA remain largely undetermined. In this study, we investigated the pro-apoptotic effects of PA in T24 human bladder cancer cells. It was found that PA could inhibit the cell growth of T24 cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies and chromatin condensation and accumulation of cells in the sub-G1 phase. The induction of apoptotic cell death by PA was connected with an up-regulation of pro-apoptotic Bax and Bad protein expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, and inhibition of apoptosis family proteins. In addition, apoptosis-inducing concentrations of PA induced the activation of caspase-9, an initiator caspase of the mitochondrial-mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. PA also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that PA may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Journal of Life Science
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• v.23 no.8
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• pp.1019-1024
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• 2013

The aims of this study were to determine antioxidation effect and neuroblastoma cell protection effect of donkey's bone and skin extracts (DBSE). DBSE was extracted by a pressure-cooker for 48 h and lyophilized. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was significantly increased with increased doses of DBSE and 40 mg/ml of DBSE showed 95.43% of the DPPH scavenging effect, which was equivalent to 1 mg/ml of vitamin C. The 2,2'-azino-bis (3-ethylbenzothiazoline-6- sulphonic acid) (ABTS) radical scavenging activity was also increased in a dose-dependent manner, and 20 mg/ml of DBSE showed 88.73% of the ABTS scavenging effect. The oxygen radical absorbance capacity (${\mu}M$ Trolox equivalent) of DBSE was significantly increased at a concentration of 10 mg/ml, which showed $132.53{\mu}M$ TE. The viability of oxidatively stressed brain cells induced by $500{\mu}M\;H_2O_2$ was protected by DBSE at concentrations greater than $50{\mu}M$. Cell viability after DBSE treatment at 50 and $100{\mu}g/ml$ was 53.78 and $54.34{\mu}M$ TE, respectively. There was no significant difference between both doses; however, 200 and $500{\mu}g/ml$ of DBSE showed 59.74 and 66.08% of cell viability, respectively indicating that DBSE protected SK-N-SH from oxidation stress. These results suggest that DBSE may have potential to be used as natural antioxidants in food industry, while in vivo evidence is necessary to support DBSE's in vitro-based antioxidative efficiency.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.1026-1031
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• 2004

Acetylcholinesterase inhibitory activity and protective effect against cytotoxicity of PC 12 cell induced by beta-amyloid protein and glutamate were examined in perilla seed methanol extract and its solvent fractions. Methanol extract of perilla seed showed dose-dependent acetylcholinesterase inhibitory activity, with n-butanol fraction showing strongest activity. Perilla seed methanol extract also decreased glutamate- and ${\beta}-amyloid$ protein $(A{\beta})-induced$ cytotoxicities of PC 12 cells dose-dependently. Formation of TBARS induced by $FeSO_{4^-}H_2O_2$ in rat brain was significantly reduced by perilla seed methanol extract, with strongest protective activity formation of TBARS shown in n-butanol fraction. Results suggest perilla seed methanol extract may attenuate actylcholinesterase activity and cytotoxicity induced by glutamate and ${\beta}-amyloid$ protein through suppression of oxidative stress.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.333-339
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• 2005

To increase IgY in egg yolks, hens were fed a feed supplemented with kelp meal $4\%$ cinnamon $0.3\%$ and mint $2\%$ respectively, and immunized 5 times with Streptococcus mutans(S. mutans) at 2 week intervals. Groups fed experimental feeds without immunization showed higher laying rate than the control group, without supplementary feed and immunization. After the immunization, the laying rates had been decreasing due to the stress of immunization. The laying rate was recovered after the termination of immunization. Egg weight was not affected by the immunization but diets. Feed intake was dependent on the laying rate. Total IgY concentration in eggs laid from hens fed feeds containing supplementary feeds was higher than that of control. Especially, total IgY was increased up to $7.9\%$ in eggs laid from hens fed feeds supplemented with $4\%$ of kelp meal. Anti-S. mutans IgY was detected at 4 weeks after first immunization. Activity of anti-S. mutans IgY was sustained at 5 week after the final immunization. As the average concentration of specific IgY during the experimental period showed that eggs from hens fed the feed containing $4\%$ of kelp meal increased the specific IgY by $8.5\%$ kelp meal supplement improved specific IgY production by immunization.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.4
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• pp.55-66
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• 1993

Upon freezing a soil swells due to phase change and its compression stress increase a lot. As the soil undergo thawing, however, it becomes a soft soil layer because the 'soil changes from a solid state to a plastic state. These changes are largely dependent on freezing temperature and repeated freezing-thawing cycle as well as the density of the soil and applied loading condition. This study was initiated to describe the effect of the freezing temperature and repeated freezing-thawing cycle on the unconfined compressive strength. Soil samples were collected at about 20 sites where soil structures were installed in Kangwon provincial area and necessary laboratory tests were conducted. The results could be used to help manage effectively the field structures and can be used as a basic data for designing and constructing new projects in the future. The results were as follows ; 1. Unconfined compressive strength decreased as the number of freezing and thawing cycle went up. But the strength increased as compression speed, water content and temperature decreased. The largest effect on the strength was observed at the first freezing and thawing cycle. 2. Compression strain went up with the increase of deformation speed, and was largely influenced by the number of the freezing-thawing cycle. 3. Secant modulus was responded sensitivefy to the material of the loading plates, increased with decrease of temperature down to - -10$^{\circ}$C, but was nearly constant below the temperature. Thixotropic ratio characteristic became large as compression strain got smaller and was significantly larger in the controlled soil than in the soil treated with freezing and thawing processes 4. Vertical compression strength of ice crystal(development direction) was 3 to 4 times larger than that of perpendicular to the crystal. The vertical compression strength was agreed well with Clausius-Clapeyrons equation when temperature were between 0 to 5C$^{\circ}$, but the strength below - 5$^{\circ}$C were different from the equation and showed a strong dependency on temperature and deformation speed. When the skew was less then 20 degrees, the vertical compression strength was gradually decreased but when the skew was higher than that, the strength became nearly constant. Almost all samples showed ductile failure. As considered above, strength reduction of the soil due to cyclic freezing-thawing prosses must be considered when trenching and cutting the soil to construct soil structures if the soil is likely subject to the processes. Especially, if a soil no freezing-thawing history, cares for the strength reduction must be given before any design or construction works begin. It is suggested that special design and construction techniques for the strength reduction be developed.

• Journal of radiological science and technology
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• v.34 no.4
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• pp.297-303
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• 2011

The existing studies of VDT syndrome have been researched only about for nurse groups without radiological technologists. The target of this study was workers who perform VDT task in general hospital placed in Daejun City such as insurance judgement, patient affairs, medical record management, medical computing service, hospital administration, and radiological sections. This study was conducted at October 15, 2009 to November 2, 2009 using structured questionnaire. Results of group A (age 20-29, less than 5 years experience at clinical site, normal staff, and unmarried group) showed significant skin and psychological conditions among recognition symptoms of VDT syndrome. Group B (age 30-39, 6-10 years experience at clinical site, managing staff, and married group) tends to be similar at orbital, whole body and muscles' frame response among recognition symptoms of VDT syndrome. Results of "Multiple Linear Regression" with dependent variable that is scores of recognition symptoms of VDT syndrome are as follows. The factors which influences for orbital-related problem is gender, health cares and obstacles during daily life. The factors which influences for whole body-related is exercise, stress and recognition for health condition and the factors which influences muscles' frame-related is 6-10 years experience at clinical site, human relationship, health cares and obstacles during daily life. These are proved to be similar by statistic analysis. There is small difference at recognition symptom of VDT syndrome between the radiological technologist and other groups in general hospital. Yet, as the working circumstance of radiological technologist gradually changes to VDT environment, the recognition symptom of VDT syndrome became conscious. This can be prevented by regular job rotation, which will escape the continuous repetition of working pattern.

• Toxicological Research
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• v.29 no.1
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• pp.43-52
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• 2013

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 ${\mu}M$) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 ${\mu}M$). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.358-364
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• 2009

We investigated the growth of ZnO thin films with prominent emission characteristics through minimizing the formation of defects by using pulsed laser deposition (PLD). To do so, the ZnO films were deposited on sapphire(0001) substrates at the substrate temperature of $400-850^{\circ}C$ and then the variation of their structural and optical properties were analyzed by x-ray diffraction, atomic force microscope and photoluminescence. As a result, all ZnO films were grown with c-axis preferential orientation irrespective of the substrate temperature. However, the crystallinity and stress state were dependent on the substrate temperature and the ZnO film deposited at $600^{\circ}C$ showed the best surface morphology and crystallinity with nearly no strain. And also this film exhibited outstanding emission characteristics from the viewpoint of full width half maximum of UV emission peak as well as visible emission due to defects. These results indicate that the emission characteristics of the ZnO films are strongly related to their structural characteristics influenced by substrate temperature. Consequently, ZnO films with strong UV emission and nearly no visible emission, which are applicable to UV emission devices, could be grown at the substrate temperature of $600^{\circ}C$ by PLD.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.557-564
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• 2007

The effect of wave and current interactions on regular wave transformation over a submerged elliptic shoal is investigated based on numerical simulations of the Vincent and Briggs experiment [Vincent, C.L., Briggs, M.J., 1989. Refraction-diffraction of irregular waves over a mound. Journal of Waterway, Port, Coastal and Ocean Engineering, 115(2), pp. 269-284]. The numerical simulations are conducted by constituting two numerical model systems: a combination of SWAN(a wave model) plus SHORECIRC(a current model) and a combination of REF/DIF 1(a wave model) plus SHORECIRC. A time dependent phase-resolving wave-current model, FUNWAVE, is also utilized to simulate the experiment. In the simulations, the breaking-induced currents defocus waves behind the shoal and bring on a wave shadow zone that shows relatively low wave height distributions. The computed results of the two model systems agree better with the measurements than the computed results obtained by neglecting wave-current interaction do. However, it is found that the radiation stresses for standing waves are misevaluated in the wave models. In addition, the results of FUNWAVE show very good agreement with the measurements. The agreement indicates that it is necessary to take into account the effect of breaking-induced current on wave refraction when wave-breaking occurs over a submerged shoal.