• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10B
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• pp.630-637
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• 2007

In this paper, we propose an effective handoff mechanism using events at the layer 2 and a tunnel-based mechanism that is performed by sharing information of a mobile node and anticipated-based handoff. Also, we propose a novel anticipated-reservation mechanism using the events triggered at layer 2 to make easy a resource reservation procedure. Comparing with the existing mobile IPv6 handoff mechanism, our proposed handoff mechanism can reduce an amount of handoff latency and traffic volume between access routers where handoff is performed. In the anticipated-reservation mechanism, the amount of signaling traffics between an mobile node and the correspondent nodes can be reduced and then the allocation of resource can be accomplished. We present the performance of our proposed handoff mechanism in the wireless network environment by ns-2 simulation. Although the anticipated-reservation mechanism including a proxy agent is explained without performance evaluation, we can validate the operation of our proposed model only by the procedure of message flow.

• Carbon letters
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• v.9 no.3
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• pp.203-209
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• 2008

The objective of this work is to study the feasibility of the preparation of the activated carbon (AC) from coconut tree flowers using high temperature fluidized bed reactor (HTFBR). The activating agent used in this work is steam. The reactor was operated at various activation temperature (650, 700, 750, 800 and $850^{\circ}C$) and activation time (30, 60, 120 and 240 min) for the production of AC from coconut tree flowers. Effect of activation time and activation temperature on the quality of the AC preparation was observed. Prepared AC was characterized in-terms of iodine number, methylene blue number, methyl violet number, ethylene glycol mono ethyl ether (EGME) surface area and SEM photographs. The best quality of AC from coconut tree flowers (CFC) was obtained at an activation temperature and time of $850^{\circ}C$ and 1 hr restectively. The effectiveness of carbon prepared from coconut tree flowers in adsorbing crystal violet from aqueous solution has been studied as a function of agitation time, carbon dosage, and pH. The adsorption of crystal violet onto AC followed second order kinetic model. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity $q_m$ was 277.78 mg/g., equilibrium time was found to be 180 min. This adsorbent from coconut tree flowers was found to be effective for the removal of CV dye.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.6
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• pp.1415-1423
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• 2007

Carbon tetrachloride ($CCl_4$)-induced liver injury depends on a toxic agent that has to be metabolized by the liver NAPDH-cytochrome P450 enzyme system to a highly reactive intermediate. Alternations in the activity of cytochrome P450 enzymes affect the susceptibility to hepatic injury from $CCl_4$. In this study, we evaluated the potential protective activity of the traditional Korean medicinal herb, Corni fructus (CF), against an experimental model of hepatotoxicity induced by $CCl_4$. The CF exhibited a hepatoprotective activity against $CCl_4-induced$ liver damage in Sprague-Dawley (SD) rats, as measured by GOT, GPT, ALP and histological observation. The CF also showed significant decrease of malodialdehyde (MDA) and increase of glutathion (GSH), catalase activity in rat liver homogenate. In addition, the expression of CYP2E1, as measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis, was significantly decreased in the liver of CF treated SD rats. But $CCl_4$ and CF has no significant effect on 1A1 and 3A1 isoform of cytochrome P450. Based on these findings, it is suggested that hepatoprotective effects of CF possibly related to antioxidative effects and regulation of CYP2E1 expression.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.459-464
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• 2006

It has been well proved that shiphandling simulators are efficient and useful facilities for training and education of cadets and seafarers. Most of the maritime universities and many maritime training institutes all over the world have installed shiphandling simulators, which play important roles in maritime education and training. However, most of the Shiphandling simulators are standalone facilities with diversities on system architectures, layouts and functions. STCW78/95 requires simulators used for simulator-based training shall be suitable for the selected objectives and training tasks. To ensure the shiphandling simulator facilities meet the requirements of STCW convention and other expanded applications, collaborated research and coordination are needed in development and application of shiphandling simulators. Performance standard should be established for shiphandling simulator systems considering the advanced research needs as well as the needs in education, training, and assessment of competence. Standardizing and exchanging shiphandling mathematical models will improve critical performance of the system. Cooperated research on model course and training assessment approaches will enhance the training standard. In addition, the rapid spread of the internet technology has shown a promising future of application of shiphandling simulators through internet. Research has been carried out on internet based integration of multiple shiphandling simulators. A multi-agent based system, including necessary hardware, has been developed. Collaborated operation of the system can be of benefit in filling the gaps of the technical and operational level and methodology between maritime universities, enhancing mutual understanding of the navigation customs and culture background among cadets and seafarers from different countries, facilitating communication and maritime English training, and extending the functions of shiphandling simulators.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.1
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• pp.59-64
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• 2015

Retinyl palmitate (RP)-loaded pectinate micro- and nano-particles (PMP and PNP) were designed for stabilization of RP that is widely used as an anti-wrinkle agent in anti-aging cosmeceuticals. PMP/PNP were prepared with an ionotropic gelation method, and anti-oxidative activity of the particles was measured with a DPPH assay. The stability of RP in the particles along with pectin gel and ethanolic solution was then evaluated. In vitro release and skin permeation studies were performed using Franz diffusion cells. Distribution of RP in each skin tissue (stratum corneum, epidermis, and dermis) was also determined. PMP and PNP could be prepared with mean particle size diameters of $593{\sim}843{\mu}m$ (PMP) and 530 nm (i.e., $0.53{\mu}m$, PNP). Anti-oxidative activity of PNP was greater than PMP due largely to larger surface area available for PNP. The stability of RP in PMP and PNP was similar but much greater than RP in pectin bulk gels and ethanolic solution. PMP and PNP showed the abilities to constantly release RP and it could be permeated across the model artificial membrane and rat whole skin. RP was serially deposited throughout the skin layers. This study implies RP loaded PMP and PNP are expected to be advantageous for improved anti-wrinkle effects.

• Resources Recycling
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• v.25 no.3
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• pp.74-81
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• 2016

Study on chlorination of ilmenite ore were carried out by using PVC(polyvinyl chloride) as the chlorinating agent in a static bed reactor for selective removal of iron. The effect of amount of PVC and reaction temperature were investigated. It was found that the removal ratio of iron increased with amount of PVC and temperature. After reaction with HCl gas generated from PVC, porous surface of the specimens were observed. As a result, HCl gas could react with iron in the central portion of ilmenite particle through these pores. Examination of data using kinetic model suggest that the selective chlorination rate is controlled by chemical reaction at the interface of particles. The activation energy for the selective chlorination of ilmenite using PVC was calculated as 20.47 kJ/mol.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.101-108
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• 2012

Interruption or prolonged reduction and subsequent restoration of blood flow into the kidney triggers the generation of a burst of reactive oxygen species (ROS), leading to injury in the tubular epithelial cells. In this study, we determined whether methanol extract of goat's-beard (Aruncus dioicus) (extract) could prevent this ischemia/reperfusion injury. When in vitro radical scavenging activity of the extract was measured using a DPPH radical quenching assay, the extract displayed slightly lower activity than ascorbic acid. One hour after administration of the extract (400 mg/kg) by intraperitoneal injection in rats, renal ischemia/reperfusion injury was generated by clamping the left renal artery for forty minutes, followed by 24 hr restoration of blood circulation. Prior to clamping the left renal artery, the right renal artery was removed. Compared with the vehicle-treated group, pretreatment with the extract significantly reduced the tubular epithelial cell injury by 37% in the outer medulla region, and consequently reduced serum creatinine concentration by 39%. Reduction in the cell injury was mediated by attenuation of Bax/Bcl-2 ratio, inhibition of caspase-3 activation from procaspase-3, and subsequent reduction in the number of apoptotic cells. Thus, goat's-beard (Aruncus dioicus) might be developed as a prophylactic agent to prevent acute kidney injury.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.223-231
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• 2002

A phosphate-solubilizing bacterium, Enterobacter intermedium 60-2G, was examined for plant growth-promotion and induction of systemic resistance using a model system of cucumber and scab disease, caused by Cladosporium cucumerinum. Compared with a nonbacterized control, treatment of cucumber with E. intermedium significantly reduced the severity of scab disease after challenge-inoculation with C. cucumerinum. Treatment of cucumber with E. intermedium also enhanced cucumber growth. The 60-2G strain showed a strong antimicrobial activity against several plant pathogenic fungi including Fusarium soysporum and Magnaporthe grisea. These results suggest the E. intermedium 60-2G is a promising candidate as a biological control agent displaying multiple beneficial properties to promote plant health.

• Biomolecules & Therapeutics
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• v.23 no.4
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• pp.345-349
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• 2015

Betulinic acid, a pentacyclic triterpene isolated from Jujube tree (Zizyphus jujuba Mill), has been known for a wide range of biological and medicinal properties such as antibacterial, antimalarial, anti-inflammatory, antihelmintic, antinociceptive, and anticancer activities. In the study, we investigated the antiviral activity on influenza A/PR/8 virus infected A549 human lung adenocarcinoma epithelial cell line and C57BL/6 mice. Betulinic acid showed the anti-influenza viral activity at a concentration of $50{\mu}M$ without a significant cytotoxicity in influenza A/PR/8 virus infected A549 cells. Also, betulinic acid significantly attenuated pulmonary pathology including increased necrosis, numbers of inflammatory cells and pulmonary edema induced by influenza A/PR/8 virus infection compared with vehicle- or oseltamivir-treated mice in vivo model. The down-regulation of IFN-${\gamma}$ level, which is critical for innate and adaptive immunity in viral infection, after treating of betulinic acid in mouse lung. Based on the obtained results, it is suggested that betulinic acid can be the potential therapeutic agent for virus infection via anti-inflammatory activity.

• Biomolecules & Therapeutics
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• v.23 no.4
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• pp.350-356
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• 2015

Functional dyspepsia (FD) is a prevalent idiopathic upper gastrointestinal (GI) disorder characterized by diverse symptomatology including epigastric pain or discomfort, postprandial fullness, and early satiety. Although its pathophysiological mechanisms have not yet been fully established, the available studies suggest that the etiology of FD is invariably multifactorial. Benachio-F$^{(R)}$ (BF) is a proprietary liquid formulation of 7 herbal extracts that has been proposed to address this multifactorial etiology using multi-drug phytotherapy. The pharmacological effects of BF, in comparison with those of two other herbal products (Whalmyungsu$^{(R)}$; WM and Iberogast$^{(R)}$; IB) were evaluated in rats. In a laparotomy-induced rat model of delayed GI transit, BF significantly accelerated the delayed gastric emptying caused by morphine, apomorphine, and cisplatin, and also significantly increased mean gastric transit, as compared to the control animals. BF markedly increased gastric accommodation in rats and produced higher gastric volume values than did the control treatment. The effects of BF were generally comparable or superior to those of WM and IB in these models. Furthermore, BF significantly stimulated biliary flow, as compared to the control treatment. These results indicated that BF might have great potential as an effective phytotherapeutic agent capable of reducing GI symptoms and increasing quality of life in FD patients.