• Polymer(Korea)
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• v.38 no.5
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• pp.573-579
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• 2014

The effect of synthesis conditions such as carbon nanotube (CNT), 2,2,2-trifluoroethylmethacrylate (3FMA), and composition of organic-inorganic material in ozone resistance and surface characteristics of ultraviolet cured organic-inorganic hybrid coating film has been investigated. Coating solution was prepared using tetraethoxysilane (TEOS), silane coupling agent methacryloyloxypropyltrimethoxysilane (MPTMS), 3FMA, various organic materials with acrylate group, and CNT, then bar-coated on substrates using applicator, and densified by UV-curing. It was found that ozone resistance and adhesion of the coating film were strongly dependent upon contents of TEOS, 3FMA, and CNT. Especially, ozone resistance, adhesion, and surface hardness of coating film with CNT were improved, relatively. Ozone resistance of coating film with a high TEOS content was increased, but adhesion was decreased. In addition, it was also found that ozone resistance of coating film was increased with contents of 3FMA. On the other hand, surface hardness was decreased with increase of 3FMA.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.208-212
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• 2020

Purpose: This study aimed to analyze the shrinkage and expansion strain of ultraviolet (UV)-cured resin according to the wavelength of the light source and compare the shrinkage and expansion. Methods: We prepared the mold with according to the ISO 4049 specimen. The size of the circle in the mold was prepared with a height of 6.02 mm and a diameter of 4 mm. UV-curable resin for three-dimensional (3D) printing was injected into the circular mold. The control group was irradiated with a wavelength of 400~405 nm using UV-curing equipment (400 group), and the experimental group was irradiated with a wavelength of 460~465 nm (460 group). Both groups were produced ten specimens. The produced specimen was first measured with a digital micrometer. After the first measurement, the specimen was immersed in a constant temperature water bath for 15 days, after which the second measurement was performed, and the third measurement was taken after 30 days. The measured values were analyzed using the independent sample t-test (α=0.05). Results: In the non-immersion water tank, the contraction was 0.9% in the 400 group and 1.3% in the 460 group. In the constant temperature bath, the expansion was high at -0.4% in the 400 group for 15 days, and the smallest expansion was -0.03% for the 400 group for 30 days. There were significant differences between the two groups (p<0.05). Conclusion: The 400 group had a lower UV resin specimen strain than the 460 group. Therefore, it is recommended to use the wavelength required by the UV-curing resin.

• Journal of the Korean Electrochemical Society
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• v.7 no.4
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• pp.189-193
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• 2004

Lithium secondary battery with gel polymer electrolyte, which was composed of POAGA and TEGDMA, was prepared and its cell performances were evaluated. Collation time decreased with increasing the contents of the monomer in the POAGA-based gel polymer electrolyte. The polymer electrolyte was stable up to 4.5V electro-chemically and its ionic conductivity was $5.2\times10^{-3}Scm^{-1}$ at room temperature. The lithium-ion polymer battery with $3.0wt\%$ curable monomer and $1.0wt\%$ monomer showed rate-capability, low-temperature performance and cycleability.

• International Journal of Oral Biology
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• v.32 no.4
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• pp.127-133
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• 2007

Oral squamous cell carcinoma (OSCC) is the most common malignancy and is a major cause of worldwide cancer mortality. The proto-oncogene c-myb plays an important role in regulation of cell growth and differentiation, and it is expressed at high levels in hematopoietic cells and many other types of cancers. However, the function of c-myb is not well known in OSCC. The present study aimed to reveal the function of c-myb and to test the alternation of cell growth and signaling by c-myb in OSCC. In this study, c-myb and dominant-negatibe myb(DNmyb) were expressed in an adenovirus-mediated gene delivery system to KB cells. The over-expressed c-myb brought increased cellular proliferation compared with control cells. However, DN-myb infected KB cells showed significant reduction of cell growth and enhanced induction of apoptosis to activate PARP and caspase 9. c-myb induced increase of IGF-I, -II and IGF-IR expressions while DN-myb down-regulated these expression. Activation of ERK and Akt/PKB pathway was shown only in c-myb transduced cells. These findings suggest that the role of c-myb in cell growth of oral cancer cells is partially mediated through the modulation of IGFs, ERK and Akt/PKB. From this results, DN-myb is strongly recommended as a curable gene for the treatment of c-myb dependent malignancies such as OSCC.

• Tuberculosis and Respiratory Diseases
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• v.78 no.1
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• pp.31-35
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• 2015

An 18-year-old woman was evaluated for a chronic productive cough and dyspnea. She was subsequently diagnosed with mediastinal non-Hodgkin lymphoma (NHL). A covered self-expandable metallic stent (SEMS) was implanted to relieve narrowing in for both main bronchi. The NHL went into complete remission after six chemotherapy cycles, but atelectasis developed in the left lower lobe 18 months after SEMS insertion. The left main bronchus was completely occluded by granulation tissue. However, the right main bronchus and intermedius bronchus were patent. Granulation tissue was observed adjacent to the SEMS. The granulation tissue and the SEMS were excised, and a silicone stent was successfully implanted using a rigid bronchoscope. SEMS is advantageous owing to its easy implantation, but there are considerable potential complications such as severe reactive granulation, stent rupture, and ventilation failure in serious cases. Therefore, SEMS should be avoided whenever possible in patients with benign airway disease. This case highlights that SEMS implantation should be avoided even in malignant airway obstruction cases if the underlying malignancy is curable.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.431-433
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• 2009

We developed 4.8 inch WQVGA e-paper on plastic substrate using organic field effect transistors (OFETs). Polyethylene naphthalate (PEN) film was used as a flexible substrate and arrays of OFETs with bottom-gate, bottom-contact structure were fabricated on it. Lowtemperature curable organic gate insulating materials were employed and polymer semiconductor solutions were ink-jetted on arrays with high-resolution. At all steps, process temperature was limited below $130^{\circ}C$. Finally, we could drive flexible e-paper displays based on OFET arrays with the resolution of 100 dpi.

• Korean Journal of Optics and Photonics
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• v.21 no.2
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• pp.69-73
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• 2010

We propose a method to enhance the response time of a twisted nematic liquid crystal (TN-LC) cell using an anisotropic polymer. Polymer networks are formed by the phase separation between a LC and a UV-curable polymer. A TN-LC cell is exposed to UV light after the mixture of LC and anisotropic polymer is injected into the TN-LC cell. As a result, turn-off time of a TN-LC cell can be decreased remarkably without any loss of the transmittance. The turn-off time of a TN-LC cell with pure LC was 16 ms, but those of polymer networked TN-LC cells were 12, 11, and 9 ms when the concentration of the polymer was 3, 5, and 10 wt%, respectively. Moreover, by virtue of the polymer network, the backflow effect and the delay time generated during the turn-off process disappeared.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.161-168
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• 2008

We propose a novel bistable nematic liquid crystal cell, which has a dual-frequency liquid crystal material and pixel-isolating polymer wall formed by an anisotropic phase separation of a mixture of liquid crystals and UV-curable pre-polymers. The proposed cell has two stable states of left- and right-handed ${\pi}$-twist. The switching between the two states is achieved by using a sequential waveform of low and high frequencies. A transmissive bistable liquid crystal display is designed, which achieves high contrast ratio by using the proposed cell and optical films.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.4
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• pp.281-291
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• 2003

Objectives: In determining to perform non-spousal artificial insemination by donor (AID) to an infertile married couple, infertile couple requires not only the thorough understanding of the medical procedure but also scrutinizing the effect, which it will have on the relationship of the family including the baby to be born itself. Materials and methods: 148 cases with non-curable male infertility were enrolled in this inquiry survey. The donor insemination questionnaire consists of 18-items which are assessing subjects' clinical properties, the background for AID practice, psychological traits, and long term influence. Results: Of the survey, 49 cases were returned (33.1%) and 10 cases (20.4%) of these gave birth after AID practice. The mean age of husbands and wives of the 49 cases were $34.6{\pm}4.2$ and $32.1{\pm}3.0$ yers old, respectively and the duration of marriage was 5 years and 4 months. In about half of the cases, AID was first suggested by husband and the decision was made by only the couple. The major reason for the operation was to form a complete family. In the item of the psychological effects, two-third of the couples felt anxiety related to the procedure which are mostly about the possible congenital or acquired deformity of baby. The AID was positively suggested in overall by all of recipients. After giving birth to a child, most couples felt positive about their decision. As a child grows up, about half of the couples felt the child as their own and expected not to tell of the AID. In overall, about 50% of couples presented satisfaction with the procedure. Conclusions: As the above results, various psychological impacts including anxiety about a child-to-be-born were accompanied to those who were recommended of AID. To overcome these problems, sufficient medical information and consultation about the course of selecting the donor and the whole procedures of AID should be provided beforehand.

• Journal of Adhesion and Interface
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• v.3 no.4
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• pp.10-18
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• 2002

Modern plastics are of great importance in many practical applications and their performance can be enhanced by surface modification to improve their hardness, wear and chemical resistance. The object of this study is invention of functional hardening coating materials which are applied to plastic, such as polycarbonate, polymethylmethacylate and acrylonitrilebutadienestyrene. In order to invention of hardening coating materials, we synthesized new silicone acrylate oligomer and prepared coating films containing silicone acrylate oligomer (SAOE) on PC substrate. The curing of coatings is performed by UV-radiation. As results of experiments, The properties of coating films which are contained SAOE is greatly improved in comparison with coating films non-contained SAOE. Especially, when 1 wt% SAOE was introduced into the coating formulation, the UV hardening coatings obtained showed the best surface hardness and gloss.