• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.494-500
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• 2014

Indium-doped zinc oxide nanocrystals (IZO NCs), capped with stearic acid (SA) of different sizes, were synthesized using a hot injection method in a noncoordinating solvent 1-octadecene (ODE). The ligand exchange process was employed to modify the surface of IZO NCs by replacing the longer-chain ligand of stearic acid with the shorter-chain ligand of butylamine (BA). It should be noted that the ligand-exchange percentage was observed to be 75%. The change of particle size, morphology, and crystal structures were obtained using a field emission scanning electron microscope (FE-SEM) and X-ray diffraction pattern results. In our study, the 5 nm and 10 nm IZO NCs capped with stearic acid (SA-IZO) were ligand-exchanged with butylamine (BA), and were then spin-coated on a thermal oxide ($SiO_2$) gate insulator to fabricate a thin film transistor (TFT) device. The films were then annealed at various temperatures: $350^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$, and $600^{\circ}C$. All samples showed semiconducting behavior and exhibited n-channel TFT. Curing temperature dependent on mobility was observed. Interestingly, mobility decreases with the increasing size of NCs from 5 to 10 nm. Miller-Abrahams hopping formalism was employed to explain the hopping mechanism insight our IZO NC films. By focusing on the effect of size, different curing temperatures, electron coupling, tunneling rate, and inter-NC separation, we found that the decrease in electron mobility for larger NCs was due to smaller electronic coupling.

• Journal of Digital Contents Society
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• v.5 no.3
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• pp.199-204
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• 2004

A problem of many fractal image compression algorithms providing good quality at low bit rate is that the decoding time rests on an iterative procedure whose complexity is imag-dependent. This paper proposes an iterative-free fractal image decoding algorithm to reduce the decoding time. In the proposed method, under the encoder previously with the same codebook image as an initial image to be used at the decoder, the fractal coefficients are obtained through calculating the similarity between the codebook image and an input image to be encoded. As the decoding time could be remarkably reduced. For verifying the validity and universality of proposed method, We evaluated and analyzed the performance of decoding time and image quality for a number of still images and a moving picture with different distributed characteristics.

• The Journal of Korean Obstetrics and Gynecology
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• v.23 no.3
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• pp.26-37
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• 2010

Purpose: This experiment is designed to find out anti-oxidant effects of Samultang-Gami which was composed of Rehmanniae Radix(RR), Angelicae Gigantis Radix, Cnidii Rhizoma(CR), Paeoniae Radix(PR), Cortex Moutan Radicis, Hedyotis Diffusa(HD) and Caesalpinia Sappan on MEF cells. Methods: In vitro antioxidant effects were measured by MTT assay, DPPH assay, cell cycle analysis, AnnexinV-FITC/PI assay and DAPI staining using MEF cells treated with various concentrations of 70% ethanol extract of Samultang-Gami. Results: 1. In the scavenging for DPPH radical, the each treated groups of PR, CR and HD showed positive effects. RR and CR increased the viability of oxidative damaged MEF cells in a dose-dependent manner. 2. 70% ethanol extract of Samultang-Gami was shown best antioxidative effect in the concentration of $0.5mg/m{\ell}$. 3. The treatment of Samultang-Gami in oxidative damaged MEF cells didn't have any effect on cell cycle restoration. but it could lower late apoptosis rate a little and be observed the protection of nucleus. Conclusion: It can be concluded that Samultang-Gami, RR and CR have antioxidant effects on MEF cells.

• Nuclear Engineering and Technology
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• v.16 no.4
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• pp.181-194
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• 1984

The in-core fuel management problem was studied by use of the calculus of variations. Two functions of interest to a public power utility, the profit function and the cost function, were subjected to the constraints of criticality, the reactor turnup equations and an inequality constraint on the maximum allowable power density. The variational solution of the initial profit rate demonstrated that there are two distinct regions of the reactor, a constant power region and a minimum inventory or flat thermal flux region. The transition point between these regions is dependent on the relative importance of the profit for generating power and the interest charges for the fuel. The fuel cycle cost function was then used to optimize a three equal volume region reactor with a constant fuel enrichment. The inequality constraint on the maximum allowable power density requires that the inequality become an equality constraint at some points in the reactor. and at all times throughout the core cycle. The finite difference equations for reactor criticality and fuel burnup in conjunction with the equality constraint on power density were solved, and the method of gradients was used to locate an optimum enrichment. The results of this calculation showed that standard non-linear optimization techniques can be used to optimize a reactor when the inequality constraints are properly applied.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.223-231
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• 2005

A quantitative risk assessment tool was used to provide estimates of the probability that foot-and-mouth (FMD) virus-contaminated, smuggled animal products are fed to susceptible swine in Korea. Sensitivity analyses were conducted to attempt to distinguish between parameter uncertainty and variability, using different assumptions on the effect of cooking at home, the effect of the fresh meat, and the effect of heat treatment at garbage processing facility. The median risk estimate was about 20.1% with a mean value of 27.4%. In a scenario regarding all beef and pork were considered as fresh meat the estimated median risk was 3.4%. The risk was greatly dependent on the survival parameters of the FMD virus during the cooking or heat treatment at garbage processing facility. Uncertainty about the proportion of garbage that is likely contaminated with FMD had a major positive influence on the risk, whereas conversion rate representing the size of a load had a major negative effect. This model was very useful in assessing the risk explored. However, the model also requires enhancements, such as the availability of more accurate data to verify the various assumptions considered such as FMD prevalence in a specific country, proportion of garbage which is recycled as feed, proportion of food discarded as garbage. Other factors including the effect of selection of animals for slaughter, ante- and post-mortem inspection, the domestic distribution of the smuggled products, and susceptible animals other than pigs, are need to be taken into account in the future model development.

• The Korean Journal of Food And Nutrition
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• v.29 no.3
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• pp.335-340
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• 2016

The objective of the present investigation was to obtain vitamin, mineral, flavonoid, and polyphenol profiles of Rudbeckia laciniata (RL), and to examine the effects of extract of RL (RLE) on various physiological activities of HaCaT keratinocyte for the utilization of RL as natural raw materials to develop functional food. To accomplish this purpose, we checked the contents of the general nutrients of RL. The contents of vitamin A, vitamin $B_1$ and vitamin $B_2$ were $7.49{\mu}g/g$, $51.96{\mu}g/g$, and $132{\mu}g/g$ respectively, while vitamin C and vitamin $D_3$ were not detected. The contents of mineral such as Ca, K and Fe were 2.01 mg/g, 6.06 mg/g and 0.03 mg/g respectively. Total flavonoid contents of RLE were 0.25 mg/g, and total polyphenol were estimated as 1.43 mg/g. Because RL contains high levels of vitamin A which is associated with skin aging, we investigated the effect of RLE on physiological function of keratinocytes with respect to skin aging. We found that RLE significantly increased the growth rate of HaCaT cells and reduced ultraviolet radiation B (UVB)-induced cellular toxicity. Also, the extract of Rudbeckia laciniata attenuated the UVB-induced reactive oxygen species (ROS) generation in a dose-dependent manner in HaCaT cells. In addition, treatment with the extract dose-dependently increased migration activity of HaCaT cells. Thus, these findings indicated that RLE could regulate the physiological activity of keratinocytes, and may be used to develop functional foods.

• Korean Journal of Medicinal Crop Science
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• v.23 no.5
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• pp.363-369
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• 2015

Background : Platycodon grandiflorum radix used as a therapeutic agent for lung and respiratory diseases in traditional Korean medicine. The saponin and sugar content in P. grandiflorum root is dependent on the drying temperature and method. In this study, we investigated saponins and antioxidant contents in dried P. grandiflorum roots either not cut or cut to different lengths. Methods and Results : P. grandiflorum roots were either cut to 0.5, 1.0 or 2.0 cm in length or left uncut. They were dried at $45^{\circ}C$ and the effect of antioxidant substances, antioxidant ability, and saponin content were investigated. P. grandiflorum roots rapidly dried out when cut to short lengths. The saponin contents (platycodin D, polygalacin D, and deapioplatycodin D) was highest in the uncut P. grandiflorum roots. When the cut lengths were long, the levels of polyphenolic compound increased. However, 2,2'-azinobis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities were higher in the samples cut to shorter lengths. Conclusions : These results suggested that the saponin and antioxidant content of P. grandiflorum roots could be maximized by controlling the drying rate of the roots via adjustments to the root cutting length.

• Journal of Pharmaceutical Investigation
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• v.36 no.5
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• pp.299-304
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• 2006

The aim of this study was to investigate the effect of deformable liposomes with sodium cholate on the skin permeation and skin deposition of arbutin, a hydrophilic skin-whitening agent. Various compositions of liposomes were prepared by the extrusion method. Particle size distribution and entrapment efficiency were determined by the laser light scattering and the gel permeation chromatography, respectively. The in vitro rat skin permeation and deposition of arbutin in various skin layers were investigated using the Keshary-Chien diffusion cells at $37^{\circ}C$. The average particle size of the deformable liposomes ranged from 217.4 to 117.4 nm, depending on the composition. The entrapment efficiency was dependent on surfactant concentration and loading dose of arbutin. The permeation rate of 5% arbutin in deformable liposomes was $8.91({\pm}1.33){\mu}g/cm^2/h$, and was not significantly different from 5% arbutin aqueous solution $[9.82({\m}0.86){\mu}g/cm^2/h]$. The deposition of arbutin was $43.34({\pm}12.13)$ and $16.99({\pm}7.83){\mu}g/cm^2$ in stratum corneum layer and epidermis/dermis layer, respectively, after 12 h of permeation study. These results are consistent with several earlier studies for the localization effect of liposomal formulations in stratum corneum, and demonstrated the feasibility of the deformable liposomes as a promising carrier for the skin deposition of hydrophilic skin-whitening compounds.

• Journal of Biomedical Engineering Research
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• v.36 no.6
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• pp.241-250
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• 2015

Noninvasive temperature monitoring is feasible with Magnetic Resonance Imaging (MRI) based on temperature sensitive MR parameters such as $T_1$ and $T_2$ relaxation times, Proton Resonance Frequency shift (PRFs), diffusion, exchange process, magnetization transfer contrast, chemical exchange saturation transfer, etc. While the temperature monitoring is very useful to guide the thermal treatment such as RF hyperthermia or thermal ablation, the optimization of the MR thermometry method is essential because the range of temperature measurement depends on the choice of the measurement methods. Useful temperature range depends on the purpose of treatment methods, for example, $42^{\circ}C$ to $45^{\circ}C$ for RF hyperthermia and over $50^{\circ}C$ for thermal ablation. In this paper, MR thermometry methods using $T_1$ and $T_2$ relaxation times and PRFs-based MR thermometry are tried on a 3.0 T MRI system and their results are reported and compared. In addition, the scanning protocol and temperature calculation algorithms from $T_1$ and $T_2$ relaxation times and PRFs are optimized for the different temperature ranges for the purpose of RF hyperthermia and/or thermal ablation.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.422-429
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• 2013

The aim of this study was to investigate the characteristics of canine uropathogenic Escherichia coli (UPEC) and the interaction between canine UPEC and human bladder epithelial cells. Ten E. coli isolates collected from dogs with cystitis were analyzed for antimicrobial resistance patterns, the presence of virulence factors, and biofilm formation. The ability of these isolates to induce cytotoxicity, invade human bladder epithelial cells, and stimulate an immune response was also determined. We observed a high rate of antimicrobial resistance among canine UPEC isolates. All virulence genes tested (including adhesins, iron acquisition, and protectin), except toxin genes, were detected among the canine UPEC isolates. We found that all isolates showed varying degrees of biofilm formation (mean, 0.26; range, 0.07 to 0.82), using a microtiter plate assay to evaluate biofilm formation by the isolates. Cytotoxicity to human bladder epithelial cells by the canine UPEC isolates increased in a time-dependent manner, with a 56.9% and 36.1% reduction in cell viability compared with the control at 6 and 9 h of incubation, respectively. We found that most canine UPEC isolates were able to invade human bladder epithelial cells. The interaction between these isolates and human bladder epithelial cells strongly induced the production of proinflammatory cytokines such as IL-6 and IL-8. We demonstrated that canine UPEC isolates can interact with human bladder epithelial cells, although the detailed mechanisms remain unknown. The results suggest that canine UPEC isolates, rather than dogspecific pathogens, have zoonotic potential.