• YAKHAK HOEJI
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• v.55 no.1
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• pp.1-10
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• 2011

Mastic is a bleed resin formed in pistacia lentiscus tree extract form the anacatdiaceae family. Mastic is used as a food ingredient in the Mediteraanean resin, and has been used by local inhabitants as a traditional medicine for relief of upper abdominal discomfort, dyspepsiaand peptic ulcer. Clinically, mastic has been effective in the treatment of benign gastric and duodenal, ulcers, giving symptomatic relief and endoscopically proven healing. In this study, to enhance activiteies of poorly water soluble Mastic with oils, surfactants and cosurfactants and then the mixure was microemulsified in aqueous media under condition of gentle agitation and digestive motility that would be encountered in the gastrointestinal tract. Formulation development and screening were based on phase diagrams and characteristics of resultant microemulsion. For optimum mastic formulation, microemulsions with various ratio (w/w%) of mastics, oils, surfactants and cosurfactants were prepared and their solubility was evaluated by monitoring particles size in their buffer through visual asessment and electrophoretic light scattering spectrophotomerter (ELS). In vitro activity of self microemulsified mastic (SME mastic) was determined by minimum ingibition concentration (MIC) test against a panel of Helicobacter pylori (H. pylori) clinical strains. Additionally, in vivo activity of SME masitc was investigated us mouse infected by CH275 of H. pylori. The mean diameter of SME mastic was less then 100 nm in water and SME mastic was showed similar antiboisis effect compared to tometronidazole, clarithromycin and omeproazole. Consequently, SME mastic would be effective system to exterminate H. pylori. If mastic were dose with combined treatment, mastic might augur well for effect of H. pylori eradication as good remedy.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.97-108
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• 2017

Web 2.0 paradigm and technologies allow users to contribute their information voluntarily and actively to online community. This paper aims to investigate key determinants of information contribution in online communities. We come up with the research model and proposed hypotheses on the basis of intensive literature review on motivation theory, information literacy, and self expression. Using survey response date collected from those who have ever experienced in uploading or providing information on online community such as social media. A total of 262 survey responses were used to test research hypotheses. The results show that self expression motive influences on information representation capability(IRC) and information contribution. The impact of Information literacy on IRC is found to be significant, and IRC is positively related to information contribution. In addition, approval motive is proven to be key determinant of IRC and information contribution. Some practical implications of these findings are discussed.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.1-6
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• 2008

Block copolymers spontaneously assemble into various nanoscale structures such as spheres, cylinders, and lamellar structures according to the relative volumn ratio of each macromolecular block and their overall molecular weights. The self-assembled structures of block copolymer have been extensively investigated for the applications such as nanocomposites, photonic crystals, nanowires, magnetic-storage media, flash memory devices. However, the naturally formed nanostructures of block copolymers contain a high density of defects such that the practical applications for nanoscale devices have been limited. For the practical application of block copolymer nanostructures, a robust process to direct the assembly of block copolymers in thin film geometry is required to be established. To exploit self-assembly of block copolymer for the nanotechnology, it is indispensible to fabricate defect-free self-assembled nanostructure over an arbitrarily large area.

• Korean Journal of Optics and Photonics
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• v.14 no.2
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• pp.175-183
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• 2003

We obtain a solution of optical parametric amplification using self-phase modulation within the Kerr media in a nonlinear interferometer with two arms. We show that it is equivalent to the solution driven by four-wave mixing and that the solution of parametric amplification is suitable to generate a parametric gain. We obtain a derivative of power gain with respect to the propagation distance and show that gain-saturation can occur as the beam propagates along the nonlinear arms. We also show a bandwidth characteristic of the parametric amplification driven by nondegenerate four-wave mixing. Numerical examples are given to illustrate that the solution of the parametric amplification can be applied to design and analysis of all-optical devices such as all-optical amplifiers.

• Journal of Pharmaceutical Investigation
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• v.37 no.6
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• pp.339-347
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• 2007

SMEDDS is mixture of oils, surfactants, and cosurfactants, which are emulsified in aqueous media under conditions of gentle agitation and digestive motility that would be encountered in the gastro-intestinal(GI) tract. The main purpose of this work is to prepare self-microemulsifying drug delivery system(SMEDDS) for oral bioavailability enhancement of a poorly water soluble drug, atorvastatin calcium. Solubility of atorvastatin calcium was determined in various vehicles. Pseudo-ternary phase diagrams were constructed to identity the efficient self-emulsification region and particle size distributions of the resultant micro emulsions were determined using a laser diffraction sizer. Optimized formulations for in vitro dissolution and bioavailability assessment were $Capryol^{(R)}$ 90(50%), Tetraglycol(16%), and $Cremophor^{(R)}$ EL(32%). The release rate of atorvastatin from SMEDDS was significantly higher than the conventional tablet ($Lipitor^{(R)}$), 2-fold. Our studies illustrated the potential use of SMEDDS for the delivery of hydrophobic compounds, such as atorvastatin calcium by the oral route.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.213-223
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• 2019

This study aims to prove the relationship between a TPB(theory of planned behavior) variables (subjective norms, attitudes, and self-efficacy), need to belong and personal growth initiatives to explain the reasons for users' shared behavior. 959 participants who had shared online video were collected as a sample through an online survey and the collected data were analyzed through structural equation modeling. The study found that need to belong affected attitudes to online video sharing and subjective norms, and that personal growth initiative also affected attitudes to online video sharing and self-efficacy. In addition, all three variables of TPB were affect the intend of online video sharing, and attitudes to online video sharing were affecting subjective norms and self-efficacy. This study is meaningful in that it demonstrated the user's intention to share online video through variables of TPB along with their need to belong and personal growth initiatives.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.1-17
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• 2021

Self-potential (SP) surveys measure naturally occurring differences in electrical potential in the absence of artificial sources and have been applied to various fields since the first application in mineral explorations. Among various causes of SP occurrences, streaming potential is generated by the flow of groundwater, and makes SP surveys suitable for the exploration of groundwater table fluctuation, fractures, sinkholes and landslide occurrences. Recently, there has been many studies that applied SP surveys to monitor water leakage through dikes and embankments. In this review paper, we first review the characteristics and theoretical backgrounds of streaming potential in saturated or unsaturated porous media to introduce it in the embankment among various application field. After the review of the background theory, we review the past cases of field SP surveys on dikes and embankments and also the characteristics of field streaming potential data in the surveys. Further, by analyzing past studies of qualitative as well as quantitative interpretation of SP survey data, we show the possibility of quantitative interpretation of streaming potential data obtained on dikes and embankments. Consequently, it is hope that this review paper helps researches on SP surveys on dikes and embankments, and provides basis for interpretation methods of the SP data to identify leaked area and further leakage rate (or permeability).

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.66-74
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• 2021

With the development of the Internet, user authentication technology that proves me online is improving. Existing ID methods pose a threat of personal information leakage if the service provider manages personal information and security is weak, and the information subject is to the service provider. In this study, as online identification technology develops, we propose a DID-based self-authentication model to prevent the threat of leakage of personal information from a centralized format and strengthen sovereignty. The proposed model allows users to directly manage personal information and strengthen their sovereignty over information topics through VC issued by the issuing agency. As a research method, a self-authentication model that guarantees security and integrity is presented using a decentralized identifier method based on distributed ledger technology, and the security of the attack method is analyzed. Because it authenticates through DID Auth using public key encryption algorithms, it is safe from sniffing, man in the middle attack, and the proposed model can replace real identity card.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.471-479
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• 2019

The purpose of this study was to investigate the determinants of preventive behavior intention to the particulate matter. The results based on the survey of 280 university students showed that the perceived susceptibility and barriers to the particulate matter do not have statistically significant effects on the preventive behavior intention. However, perceived severity and benefits, subjective norm, and self-efficacy to the particulate matter had statistically significant positive effects on the preventive behavior intention. The results of this study suggested that communication strategies to increase perceived severity and benefits, subjective norm and self-efficacy should be required to improve the degree of preventive behavior intention to the particulate matter of college students. It is expected to contribute explaining preventive actions against environmental hazards such as air pollution in the future.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.149-163
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• 2019

Under non-uniform electric field, a directional force along the electric field gradient is applied to matter having permanent or induced dipoles. The transport of particles by the directional force is called dielectrophoresis (DEP). Since the strength and direction of the DEP force depend on parameters, such as permittivity and conductivity of particles and surrounding media, and frequency of the applied AC electric field, particle can be precisely manipulated by controlling the parameters. Moreover, unlike electrophoresis, DEP can be applied to any particles where dipole is effectively induced by electric field. Such a DEP technique has been used in various fields, ranging from microfluidic engineering to biosensor and microchip research. This paper first describes the fundamentals of DEP, and discusses representative microelectrode designs used for DEP study. Then, exemplary applications of DEP, such as separation, capture and self-assembly of particles, are introduced.