• 천문학회지
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• 제44권2호
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• pp.59-65
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• 2011

A small number of active galactic nuclei are known to exhibit prominent double peak emission profiles that are well-fitted by a relativistic accretion disk model. We develop a Monte Carlo code to compute the linear polarization of a double peaked broad emission line arising from Thomson scattering. A Keplerian accretion disk is adopted for the double peak emission line region and the geometry is assumed to be Schwarzschild. Far from the accretion disk where flat Minkowski geometry is appropriate, we place an azimuthally symmetric scattering region in the shape of a spherical shell sliced with ${\Delta}{\mu}=0.1$. Adopting a Monte Carlo method we generate line photons in the accretion disk in arbitrary directions in the local rest frame and follow the geodesic paths of the photons until they hit the scattering region. The profile of the polarized flux is mainly determined by the relative location of the scattering region with respect to the emission source. When the scattering region is in the polar direction, the degree of linear polarization also shows a double peak structure. Under favorable conditions we show that up to 0.6% linear polarization may be obtained. We conclude that spectropolarimetry can be a powerful probe to reveal much information regarding the accretion disk geometry of these active galactic nuclei.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.130-139
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• 2004

The cladding materials remaining after reprocessing process of the nuclear fuel, generally called as hulls, are classified as a high-level radioactive waste. They are usually packaged in the container for disposal after being compacted, melted, or solidified into the matrix. The efforts to fabricate a better ingot for a more favorable disposal to the environment have failed due to the technical difficulties encountered in the chemical decontamination method. In the early 1990s, the accumulation of radio-chemical data on hulls and the advent of new technology such as a laser or plasma have made the pre-treatment of the hulls more efficient. This paper summarizes the information regarding the radio-chemical analysis of the hull through a literature survey and determines the characteristics of the hull and depth profile of the radio-nuclides within the hull thickness. The feasibility study was carried out to evaluate the reduction of the radioactivity by peeling off the surface of the hull with the application of laser technology.

• Journal of Pharmaceutical Investigation
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• 제32권4호
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• pp.327-330
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• 2002

Alginate based polymeric matrices were designed for controlled release and stabilization of cefaclor in gastrointestinal fluid. Cefaclor is known to be acid stable and subjected to be degraded at neutral and alkaline pHs. In order to achieve an effective release profile of cefaclor in gastrointestinal tract, a particular strategy in dosage form design should be required from the view point of maintaining its activity. The amphiphilic nature of cefaclor allowed its controlled release using ionic polymers based on ionic interaction between the drug and polymers. The thrust of this study was to develop a technique that delivers cefaclor keeping effective release rate in the intestinal tract. Considering the fast degradation of cefaclor in the intestinal fluid, the matrices were designed to release surplus amount of cefaclor. The alginate based matrices demonstrated increase in release rate in the simulated intestinal fluid, which was favorable to compensate the degraded portion of cefaclor. In addition, stabilization of cefaclor in the intestinal fluid was obtained by employing citric acid that provides an local acidic environment. The matrices might be valuably used for the development of an oral cefaclor dosage form.

• Journal of Microbiology and Biotechnology
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• 제1권3호
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• pp.212-219
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• 1991

Four species of yeast, Saccharomyces cerevisiae, Candida utilis, Saccharomycopsis flbuligera, and Schwanniomyces castellii were evaluated for their ability to bioconvert potato processing waste water into microbial protein and the resulting single-cell proteins were evaluated as protein sources for rainbow trout, using in vitro analyses. The studies indicated that Schwanniomyces castellii, which utilizes starch dircetly and converts it into cell mass efficiently, was suitable for the bioconversion. In the single-stage continuous bioconversion, the yield S. castellii cell mass, which contained approximately 37% protein, was 77%, at dilution rate 0.25 $h^{-1}$. Reduction of total carbohydrate was 81%. During batch fermentations, cell mass yield was about 72% and total carbohydrate reduction was 81%. Among the yeasts tested, S. castellii possessed the most fragile cell wall and had a favorable amino acid profile for salmonid fish; protein score of 86% (Met). In an in vitro pepsin digestibility test 80% digestibility (23~38% above control) was observed when cells were pre-heated in a steam bath for 30 min. Results presented should be regarded as being preliminary in nature because they were derived from single experiments.

• Korea-Australia Rheology Journal
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• 제16권2호
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• pp.101-108
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• 2004

The hemodynamics behavior of the blood flow is influenced by the presence of the arterial stenosis. If the stenosis is present in an artery, normal blood flow is disturbed. In the present study, the characteristics of pulsatile flow in the blood vessel with stenosis are investigated by the finite volume method. For the validation of numerical model, the computation results are compared with the experimental ones of Ojha et al. in the case of 45％ stenosis with a trapezoidal profile. Comparisons between the measured and the computed velocity profiles are favorable to our solutions. Finally, the effects of stenosis severity and wall shear stress are discussed in the present computational analysis. It can be seen, where the non-dimensional peak velocity is displayed for all the stenosis models at a given severity of stenosis, that it is exponentially increased. Although the stenosis and the boundary conditions are all symmetric, the asymmetric flow can be detected in the more than 57％ stenosis. The instability by a three-dimensional symmetry-breaking leads to the asymmetric separation and the intense swirling motion downstream of the stenosis.

• Preventive Nutrition and Food Science
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• 제20권2호
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• pp.148-152
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• 2015

To develop functionally and nutritionally improved whole soybean curd (WSC), the effects of partial (0~4%) replacement with pine needle powder (PNP) on the quality characteristics of WSC were investigated. The moisture content and pH ranged from 76.96~77.80% (wet basis) and 6.69~6.74, respectively, with no considerable differences. Lightness significantly decreased with higher PNP content in the formulation (P<0.05), as indicated by visual observation that the color of WSC became darker. Redness and yellowness also significantly decreased (P<0.05). The texture profile analysis indicated that WSC containing PNP was softer and less cohesive than control WSC. 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical scavenging activities significantly increased (P<0.05) with higher substitution of PNP, and they were well correlated. Results from the consumer test revealed that WSC with 1% PLP received the most favorable acceptance scores for sensory attributes, including overall acceptability. The present study indicated that the characteristics of PNP may play a role in improving WSC quality in terms of physicochemical, sensorial, and antioxidant characteristics.

• Preventive Nutrition and Food Science
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• 제6권2호
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• pp.87-90
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• 2001

The volatile flavor components of snow crabs from the Young-duk coast of Korea and their concentrated cooker effluent were isolated by a modified method from Likens and Nickerson, using a simultaneous distillation and extraction apparatus. The concentrated extract was analyzed and identified by gas chromatography and GC-MS. The flavor profile of boiled crab demonstrated that the favorable flavor characteristic of crab involved a seafood-like note, and that of concentrated cooker effluent demonstrated that the weak boiled crab flavor involved a fishy note. The main flavor components of boiled crab were heterocyclic compounds including alkylpyrazines, thizoles and thiolanes, aliphatic ketones including 2-heptanone and nonanone. On the other hand, the main flavor components of cooker effluent were aldehydes including 3-methylbutanal, alipatic ketones including 2-heptanone and alkanes including 2,6,10,14-tetramethyl-pentadecane. Almost all of heterocyclic compounds, which seem to be important contributors to the flavor of boiled crab, were not identified in concentrated cooker effluent. As a result, there may be a need to add the crab flavor components formed through model experiments of Maillard reactions to the concentrated cooker effluent for human consumption.

• Journal of Pharmaceutical Investigation
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• 제40권5호
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• pp.285-289
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• 2010

Manufacturing a multi-layered tablet such as Xatral XL$^{(R)}$ is more complex and expensive than monolayered tablets, but mono-layered tablets may have less favorable release properties depending on the pharmacodynamics and pharmacokinetics of the active ingredient. We therefore sought to develop a monolayer tablet with a similar dissolution profile to the commercial alfuzosin sustained-release triple layered tablet (Xatral XL$^{(R)}$). We prepared four different mono-layered alfuzosin tablets with different concentrations of hydroxypropyl methycellulose and PVP K-90. Fomulation III with alfuzosion/mg-stearate/ HPMC/ PVP K-90 (10/5/110/95 mg/tab) has a similar dissolution rate to Xatral XL$^{(R)}$, with a similarity factor score of 81.4. However, the swelling and erosion rates of the two formulations were different, and NIR analysis showed differences in the mechanisms of drug release. Thus, although formulation III and Xatral XL$^{(R)}$ show similar dissolution rates, the mechanisms of drug release are different.

• 구강회복응용과학지
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• 제22권1호
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• pp.55-74
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• 2006

The external contour of an implant can have significant effects on the load transfer characteristics and may result in different bone failure rates for different implant system. The purpose of this study was to investigate the effects of crest module shape and occlusal load direction on bone failure modes of five commercially available dental implant systems. Five different implant systems with internal connection; ITI (Model 1), Astra (Model 2), Bicon (Model 3), Friadent (Model 4), and Paragon (Model 5), comparable in size, but different in thread profile and cest module shapes, were compared using the finite element method. Conclusively, in the internal connection system of the implant-abutment connection methods, the stress-induced pattern at the supporting bone according to the abutment connection form had differenence among them, and implants with narrowing crestal module cross-sections at the top of the cortical bone created more favorable load transfer characteristics in this region. But it is considered that the future study is necessary about how this difference in the magnitude of the stress have an effect on the practical clinic.

• Animal cells and systems
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• 제7권3호
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• pp.207-211
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• 2003

Caveolin-1 is a principal protein in the plasma membrane microdomains called caveolae. Caveolae play an important role in the transcytosis and pinocytosis. Therefore, caveolin-1 is most likely to work for the membrane dynamic events. In addition, caveolin-1 interacts with various signaling molecules. Although caveolin-1 possesses a variety of physiological functions, its structural properties were little construed. Here we analyzed the structural dynamics of the N-terminal caveolin-1 (residues 1-101), in order to better understand the structural properties in terms of its versatile functionality. We first analyzed its oligomeric form using GST-fused N-terminal domain, revealing that it equilibrates between a dimer and monomers in av concentration-dependent manner. The N-terminal domain of caveolin-1 was previously found to form a heptamer, so that our data suggest the dimeric form as an intermediate structure for the heptamer formation. Then, we obtained the folding profile, which indicated that $\DeltaG_{H2O}\;is\;about\;0.5\;\pm0.03$ kcal/mol. The stability of N-terminal domain is relatively low, indicating that N-terminal domain may not be crystalline. Conclusively, the dynamic and flexible structure of N-terminal domain appears more favorable to maintain the versatile functions of caveolin-1.