• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.1
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• pp.37-46
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• 2017

Background: In oxidative stress, reactive oxygen species (ROS) production contributes to cellular dysfunction and initiates the apoptotic cascade. Autophagy is considered the mechanism that decreases ROS concentration and oxidative damage. Propofol shows antioxidant properties, but the mechanisms underlying the effect of propofol preconditioning (PPC) on oxidative injury remain unclear. Therefore, we investigated whether PPC protects against cell damage from hydrogen peroxide ($H_2O_2$)-induced oxidative stress and influences cellular autophagy. Method: COS-7 cells were randomly divided into the following groups: control, cells were incubated in normoxia (5% $CO_2$, 21% $O_2$, and 74% $N_2$) for 24 h without propofol; $H_2O_2$, cells were exposed to $H_2O_2$ ($400{\mu}M$) for 2 h; $PPC+H_2O_2$, cells pretreated with propofol were exposed to $H_2O_2$; and 3-methyladenine $(3-MA)+PPC+H_2O_2$, cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to $H_2O_2$. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) reduction. Apoptosis was determined using Hoechst 33342 staining and fluorescence microscopy. The relationship between PPC and autophagy was detected using western blot analysis. Results: Cell viability decreased more significantly in the $H_2O_2$ group than in the control group, but it was improved by PPC ($100{\mu}M$). Pretreatment with propofol effectively decreased $H_2O_2$-induced COS-7 cell apoptosis. However, pretreatment with 3-MA inhibited the protective effect of propofol during apoptosis. Western blot analysis showed that the level of autophagy-related proteins was higher in the $PPC+H_2O_2$ group than that in the $H_2O_2$ group. Conclusion: PPC has a protective effect on $H_2O_2$-induced COS-7 cell apoptosis, which is mediated by autophagy activation.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.185-192
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• 2010

The objective of this study was to investigate the effectiveness of stabilization for army firing range soil highly contaminated with Pb (total Pb: 29,000 mg/kg) using calcined waste oyster shells. The calcination was conducted to activate quicklime from calcite. In order to evaluate the effectiveness of calcination, both natural oyster shells (NOS) and calcined oyster shells (COS) were applied to the Pb contaminated soil. Stabilization was conducted by mixing the contaminated soil with oyster shell media at 5-20 wt% and cured for 28 days. Following 28 days of curing, Pb leachability was measured based on the Korean Standard Test method (0.1 N HCl extraction). The treatment results showed that the COS treatment outperformed the NOS treatment. All of the NOS treatments failed to meet the Korean warning standard of 100 mg/kg. However, the Pb concentrations were significantly reduced to 47 mg/kg and 3 mg/kg upon 15 wt% and 20 wt% COS treatments, respectively which passed the Korean warning standard. Moreover, -#20 mesh materials were more effective than the -#10 mesh materials in effectively reducing Pb leachability. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results indicated that Pb immobilization was strongly linked to Al and Si.

• Polymer(Korea)
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• v.32 no.3
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• pp.263-269
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• 2008

To develop carriers of hydrophobic anticancer agents based on chitosan, chitosan oligosaccharide lactate (COS) was chemically modified with lithocholic acid (LA) which is one of the bile acids as a hydrophobic group. The physicochemical properties of the lithocholic acid conjugated chitosan nanoparticles (COS-LA) were investigated using $^1H$-NMR spectroscopy, dynamic light scattering (DLS) and spectrofluorophotometer. COS-LA-paclitaxel (CLs-Tx) nanoparticles loading paclitaxel as an anticancer agent were prepared by a dialysis method and its loading efficiency was measured through HPLC. On the basis of DLS results, the estimated particle sizes of CLs-Tx were around 300 nm. Also, the critical micelle concentration (CMC) was proven to be dependent on the degree of substitution of lithocholic acid. It showed that the CLs-Tx has the superior potential for the application as a paclitaxel carrier.

• Journal of the Korean Magnetics Society
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• v.18 no.4
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• pp.142-146
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• 2008

The angular dependence of the exchange bias($H_{ex}$) and coercivity($H_c$) in multilayer $[Pt/Co]_N-IrMn$ with applied measuring field rotated toward in-plane at angle $\theta$ from perpendicular-to-plane, has been measured. Multilayer films consisting of $Si/SiO_2/Ta(50)/Pt(4)/[Pt(15)/Co(t_{Co})]_N/IrMn(50)/Ta(50)(in\;{\AA})$ were prepared by magnetron sputtering under typical base pressure below $2{\times}10^{-8}$ Torr at room temperature. Magnetization measurements were performed on a vibrating sample magnetometer and extraordinary Hall voltage measurement systems after cooling from 550 K under a field of 2 kOe applied along the perpendicular to film direction. The hysteresis loop shifts from the origin not only along the field axis but also along the magnetization axis. $H_{ex}$ and $H_c$ show a $1/cos{\theta}$ and $1/|cos{\theta}|$ dependence on the angle($\theta$) between the applied measuring field and the perpendicular-film direction, respectively. This $1/cos{\theta}$ dependence can be accounted for by considering the angular dependence of strong out-of-plane magnetic anisotropy introduced during the field cooling.

• The Korea Journal of Herbology
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• v.37 no.4
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• pp.49-57
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• 2022

Objective : This study was conducted to investigate antidiabetic effects of chunggugjang with medicinal herbal complex (CJ) in streptozotocin (STZ)-induced animal models. Method : STZ (65 mg/kg) was injected intraperitoneally to induce diabetes. Then rats were divided into 5 groups ; NG (normal diet + 0.9% saline), COS (STZ +saline 5 mL/kg), COB (STZ + fermented soybean(100 mg/kg), CJ 100/200 (STZ+CJ(100 and 200 mg/kg), CJ 300/600 (STZ+CJ(300 and 600 mg/kg). 4 weeks later, oral glucose tolerance test (OGTT) was performed. After sacrificing rats, serum levels of blood urea nitrogen (BUN), creatinine, aspartate amino transferase (AST), alanine amino transferase (ALT), total cholesterol (TC), and triglyceride (TG) were measured and histological changes were observed. Result : Body weight change and food efficiency ratio (FER) were decreased in the CJ 300/600 group than in the COS group. But, there was no change in water intake. Serum levels of glucose, AST, ALT and BUN were lower in the CJ 300/600 group than in the COS group. Also, TG, TC, and creatinine were decreased in the CJ 300/600 group than in the COS group. According to OGTT, 120 minutes postprandial glucose levels were lower in the CJ 300/600 group than in the COS group. In addition, administration of CJ extracts restored histopathological damage. Conclusion : The results suggest that CJ can be used as a functional material for diabetes treatment as it has the effect to improve pathological symptoms in STZ-induced diabetic rats.

• 전기산업
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• v.2 no.2
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• pp.62-67
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• 1991

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.10a
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• pp.171-175
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• 1998

• Korean Architects
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• s.633
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• pp.76-83
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• 2022

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1119-1127
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• 2007

This paper is concerned with a performance analysis using a wired/wireless hybrid network based on Common Industrial Protocol(CIP). For the performance analysis, the data transmission time, average end-to-end delay and throughput between DeviceNet and the wireless devices are investigated. The experimental results show the performance in terms of the polling/COS service time of CIP based hybrid network.

• The Journal of Society for e-Business Studies
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• v.4 no.3
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• pp.197-212
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• 1999

In general, the electronic commerce systems comprise the background system, terminal, network and smart cards. Among them, the smart card systems are expected to take a great portion of applications for the convenience of rapidly improving technology. The technology includes adopting RISC processors or co-processors for cryptography and developing new memory systems based on the standardization. In this paper, we investigate the overall trends of the technology and the standardization process of smart cards. We also propose the guidelines to enhance the capabilities of designing H/W and S/W related to COS(Chip Operating System).