• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1383-1389
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• 2011

The current study focuses on the consistent analysis of heat transfer in multichannel volumetric solar receivers used for concentrating solar power. Changes in the properties of the absorbing material and channel dimensions are considered in an optical model based on the Monte Carlo ray-tracing method and in a one-dimensional heat transfer model that includes conduction, convection, and radiation. The optical model results show that most of the solar radiation energy is absorbed within a very small channel length of around 15 mm because of the large length-to-radius ratio. Classification of radiation losses reveals that at low absorptivity, increased reflection losses cause reduction of the receiver efficiency, notwithstanding the decrease in the emission loss. As the average temperature increases because of the large channel radius or small mass flow rate, both emission and reflection losses increase but the effect of emission losses prevails.

• Development and Reproduction
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• v.15 no.1
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• pp.53-59
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• 2011

Sex steroid hormones are key molecules to prepare the decidual response and their levels are important in this process. Imbalances of the levels of steroid hormones are cause of implantation failure and other diseases including physical weakness. Androgen replacement therapy or selective androgen receptor modulator are used to overcome various diseases but long-term use may cause of side effects. In previous report, it is suggested that the steroid hormonal complexes derived from pig enhance the proliferation of satellite cell. Therefore, to evaluate the possible usage of steroid hormonal complex derived from pig testis (tS-C), the effects of tS-C on uterine response were studied using the model of artificial decidua. tS-C did not disturb the rhythmical estrus cycle. Artificial-induced decidual response was normally induced in tS-C administered mice. The histological characters of the decidua of tS-C administered mice were not different from the vehicle. The expression patterns of molecular markers of decidua were not different between vehicle and tS-C group. Collectively these results suggested that tS-C does not disturb the uterine responsibility to the embryo. In addition, our results suggested that tS-C can be applied to overcome the various problems such as loss of muscle mass and anemia.

• Journal of Broadcast Engineering
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• v.18 no.6
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• pp.808-815
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• 2013

In this paper, we propose a novel fast and low-complexity Motion Estimation (ME) algorithm for Ultra High Definition (UHD) High Efficiency Video Coding (HEVC). Motion estimation occupies 77~81% of the amount of computation in HEVC. After all, the main key of video codec implementation is to find a fast and low-complexity motion estimation algorithm and architecture. We analyze the previous motion estimation algorithms and propose three optimal algorithm to reduce the computation proportion for HEVC. The proposed algorithm uses only 0.36% of the amount of operations compared to full search algorithm while maintaining compression performance with slight loss of 1.1%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.227-235
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• 2005

Skin aging is not a disease nor an abnormal phenomenon but a collection of degenerative changes with age, characterized by skin dryness, wrinkle formation, and loss of skin elasticity. The skin wrinkles are caused by either genetically predisposed factors or environmental factors such as UV irradiation or physical/chemical stimulus. The histological manifestations of wrinkles are changes in both amount and integrity of elastic and collagen fibers. Here we report the isolation and characterization of 3 active compounds, prangenidin, 8-hydroxybergapten, and xanthotoxol from Angelica dahurica root. The anti-wrinkle activities of these compounds were also investigated.

• Korean Journal of Materials Research
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• v.25 no.6
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• pp.274-278
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• 2015

The possibility of using the chemical precipitation method of up-cycled ammonium paratungstate (APT) was studied and compared with the thermal decomposition method. $WO_3$ particles were synthesized by chemical precipitation method using a 1:2 weight ratio of APT: Di-water. For thermal decomposition, APT powder was heated for 4h at $600^{\circ}C$ in air atmosphere. The reaction products were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), particle size analyzer (PSA), and field emission-scanning electron microscopy (FE-SEM). Thermogravimetric analysis (TGA) of the up-cycled APT allowed for the identification of the sequence of decomposition and reduction reactions that occurred during the heat treatment. TGA data indicated a total weight loss of 10.78% with the reactions completed in $658^{\circ}C$. The XRD results showed that APT completely decomposed to $WO_3$ by thermal decomposition and chemical precipitation. The particle size of the synthesized $WO_3$ powders by thermal decomposition with 2 h of planetary milling was around $2{\mu}m$ During the chemical precipitation process, the particle size of the synthesized $WO_3$ powders showed a round-shape with ${\sim}0.6{\mu}m$ size.

• Journal of Genetic Medicine
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• v.12 no.1
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• pp.44-48
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• 2015

Townes-Brocks syndrome (TBS) is a rare genetic disorder characterized by the classic triad of congenital anomalies of the anus, thumbs, and ears, with variable expressivity. Additionally, renal malformations, cardiac anomalies, and endocrine and eye abnormalities can accompany TBS, although less frequently. TBS is inherited in an autosomal dominant fashion; however, about 50% of patients have a family history of TBS and the remaining 50% have de novo mutations. SALL1, located on chromosome 16q12.1, is the only causative gene of TBS. SALL1 acts as a transcription factor and may play an important role in inducing the anomalies during embryogenesis. Clinical features of TBS overlap with those of other multiple anomaly syndromes, such as VACTERL syndrome, Baller-Gerold syndrome, Goldenhar syndrome, cat eye syndrome, and Holt-Oram syndrome. Consequently, there are some difficulties in differential diagnosis based on clinical manifestations. Herein, we report a Korean family with two generations of TBS that was diagnosed based on physical examination findings and medical history. Although the same mutation in SALL1 was identified in both the mother and the son, they displayed different clinical manifestations, suggesting a phenotypic diversity of TBS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.21-21
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• 2010

(Ba,Sr)$TiO_3$ (BST) thin film with a perovskite structure has potential for the practical application in various functional devices such as nonvolatile-memory components, capacitor, gate insulator of thin-film transistors, and electro-optic devices for display. Normally, the BST thin films derived from sol-gel and sputtering are amorphous or partially crystalline when processed below $600^{\circ}C$. For the purpose of integrating BST thin film directly into a Si-based read-out integrated circuit (ROIC), it is necessary to process the BST film below $400^{\circ}C$. The microstructural and electrical properties of low-temperature crystallized BST film were studied. The BST thin films have been fabricated at $350^{\circ}C$ by UV-assisted rapidly thermal annealing (RTA). The BST films are in a single perovskite phase and have well-defined electrical properties such as high dielectric constant, low dielectric loss, low leakage current density, and high breakdown voltage. Photoexcitation of the organics contained in the sol-gel-derived films by high-intensity UV irradiation facilitates elimination of the organics and formation of the single-crystalline phase films at low temperatures. The amorphous BST thin film was transformed to a highly (h00)-oriented perovskite structure by high oxygen pressure processing (HOPP) at as low as $350^{\circ}C$. The dielectric properties of BST film were comparable to (or even better than) those of the conventionally processed BST films prepared by sputtering or post-annealing at temperature above $600^{\circ}C$. When external pressure was applied to the well-known contractive BST system during annealing, the nucleation energy barrier was reduced; correspondingly, the crystallization temperature decreased. The UV-assisted RTA and HOPP, as compatible with existing MOS technology, let the BST films be integrated into radio-frequency circuit and mixed-signal integrated circuit below the critical temperature of $400^{\circ}C$.

• Herbal Formula Science
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• v.28 no.2
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• pp.169-177
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• 2020

Objectives : This experiment was designed to assess the single oral toxicity of Ethanol Extract Inulae Flos (IF) ethanol extracts. IF is one of the important herbs to remove phlegmy which is the viscous turbid pathological product that can accumulate in the body, causing a variety of diseases. Nevertheless, there has been a lack of research on the pharmacology toxicity of IF. Methods : In this study, IF was orally administered to 5 weeks ICR mice as an oral dose of 2,000 or 3,000 or 5,000 mg/kg. The condition of the mice was observed for 14 days and their weights were measured every two days. Results : None of the mice died for 14 days. The abnormal clinical symptoms and anatomical signs of toxicity were not found in any treatment groups. The gain of net body weight was observed. There was also no significant difference in the organ weight. The serum biochemistry and hematological analysis showed a decrease in BUN, red blood cells, white blood cells and platelets although within the normal ranges. Conclusions : These results suggest that the 50% lethal dose of IF is more than 5,000 mg/kg. This could be thought that IF is a safe drug without acute toxicity and side effects. However, IF showed some weight loss and change in blood test, so it will need to be careful when using it for high doses.

• Clinical and Experimental Pediatrics
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• v.62 no.11
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• pp.422-427
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• 2019

Background: Polyomavirus BK (BKV) infection is an important cause of graft loss in kidney transplant patients. Purpose: The purpose of this study was to evaluate clinical findings and risk factors for BKV in pediatric patients after kidney transplantation. Methods: This retrospective single-center study included 31 pediatric kidney transplant recipients from January 2002 to December 2017. Two patients received 2 transplantations during the study period, and each transplant was analyzed independently. Total number of cases is 33 cases with 31 patients. BKV infection was confirmed from blood samples via periodic quantitative polymerase chain reaction. Results: The mean age at kidney transplantation was 11.0±4.7 years, and the male-to-female ratio was 2.7:1. Three patients had a past medical history of high-dose chemotherapy and autologous stem-cell transplantation for solid tumors. Nine patients (27.3%) developed BKV infection. The median period from kidney transplantation to BKV detection in blood was 5.6 months. There was no statistically significant difference in estimated glomerular filtration rate between patients with and those without BKV infection. Among 9 patients with BKV viremia, 7 were treated by reducing their immunosuppressant dose, and BKV was cleared in 6 of these 7 patients. In the other 2 BKV-positive patients, viremia improved without immunosuppressant reduction. Conclusion: BKV infection is common in children with kidney transplantation and might not have affected short-term renal function in our patient sample due to early immunosuppressant reduction at the time of BKV detection.

• Composites Research
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• v.33 no.4
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• pp.205-212
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• 2020

In this study, HfC was coated on two types of carbon/carbon composites coated with SiC by vacuum plasma spraying(VPS). The experiment was performed using a plasma wind tunnel with heat flux of 5.06 MW/㎡ for 120 s heat flux before and after the coating. The mass ablation rate was calculated through the mass change before and after the test, and the length change was measured by using calipers and high speed camera. The oxidation/ablation behavior were observed by FE-SEM with EDS analysis of the specimens cross section. The plasma wind tunnel test results showed that the coated specimens had low weight loss and length change, and high oxidation/ablation resistance. However, two types of the specimens tested under the same conditions were different in the ablation behavior and ablation rate, and it was evaluated that the cylindrical type had higher oxidation/ablation resistance.