• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.11.2-11.2
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• 2011

Polymer based organic photovoltaics have attracted a great deal of attention due to the potential cost-effectiveness of light-weight and flexible solar cells. However, most BHJ polymer solar cells are not thermally stable as subsequent exposure to heat drives further development of the morphology towards a state of macrophase separation in the micrometer scale. Here we would like to show three different approaches for developing new electroactive polymers to improve the thermal stability of the BHJ solar cells, which is a critical problem for the commercialization of these solar cells. For one of the examples, we report a new series of functionalized polythiophene (PT-x) copolymers for use in solution processed organic photovoltaics (OPVs). PT-x copolymers were synthesized from two different monomers, where the ratio of the monomers was carefully controlled to achieve a UV photo-crosslinkable layer while leaving the ${\pi}-{\pi}$ stacking feature of conjugated polymers unchanged. The crosslinking stabilizes PT-x/PCBM blend morphology preventing the macro phase separation between two components, which lead to OPVs with remarkably enhanced thermal stability. The drastic improvement in thermal stabilities is further characterized by microscopy as well as grazing incidence X-ray scattering (GIXS). In the second part of talk, we will discuss the use of block copolymers as active materials for WOLEDs in which phosphorescent emitter isolation can be achieved. We have exploited the use of triarylamine (TPA) oxadiazole (OXA) diblock copolymers (TPA-b-OXA), which have been used as host materials due to their high triplet energy and charge-transport properties enabling a balance of holes and electrons. Organization of phosphorescent domains in TPA-b-OXA block copolymers is demonstrated to yield dual emission for white electroluminescence. Our approach minimizes energy transfer between two colored species by site isolation through morphology control, allowing higher loading concentration of red emitters with improved device performance. Furthermore, by varying the molecular weight of TPA-b-OXA and the ratio of blue to red emitters, we have investigated the effect of domain spacing on the electroluminescence spectrum and device performance.

• The korean journal of orthodontics
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• v.14 no.1
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• pp.53-65
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• 1984

The purpose of this study was to investigate the histopathological change and adaptation process of the mandibular joint of the rat by muscle alteration. For this study, one hundred and twenty eight rats of 25 - and 60 - day old of age were used. Unilateral and bilateral detachment, with anterior positioning of the Masseter muscle, was performed under anesthesia. The animal was sacrified 10, 20, 50, 80 days postoperatively. This alteration in muscle function led to change in neuromuscular activity and demonstrated the adaptive nature of the condyle cartilage to functional demand. The results were as follows : 1. In the right muscle detached group, operated at 25 days of age, marked decrease on the chondroblastic zone was found in the condyle head on the right side of animals examined 10 days postoperatively. Comparing with the control group, no difference was found on the chondroblastic zone in the condylar head of animals examined 20, 50 and 80 days postoperatively. 2. In the bilateral muscle detached group, operated at 25 days of age, the chondroblastic zone was slightly decreased in the anterior parts of condylar head of animals examined 10 days postoperatively. 3. In the unilateral and bilateral muscle detached group, operated at 60 days of age, no significant change was found in the mandibular joint regardless of the post operative experimental periods. 4. Under Toluidine blue staining, slightly decreased metachromasia was found in the condyle head on the right side of unilateral experimental animals, operated at 25 days of age and examined 10 days postoperatively. 5. Under Masson's trichrome staining, increased metachromasia was found in the condyle head on the right side of unilateral experimental animals, operated at 25 days of age and examined 10 days postoperatively. In summary, the condyle of the rat could respond to changes in neuromuscular activity depend on the level of maturation of the tissue, because the endochondral bone formation of the condyle of the rat was almost ended within 3 months.

• BMB Reports
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• v.35 no.4
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• pp.389-394
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• 2002

$[Ru(bpy)_2(dppz)]^2+$ (bpy=2,2'-bipyfidine, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuBD), a long-lifetime metal-ligand complex, displays favorable photophysical properties. These include long lifetime, polarized emission, but no significant fluorescence from the complex that is not bound to DNA. To show the usefulness of this luminophore (RuBD) for probing the bending and torsional dynamics of nucleic acids, its intensity and anisotropy decays when intercalated into supercoiled and relaxed pTZ18U plasmids were examined using frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. The mean lifetimes for the supercoiled plasmids (< $\tau$ >=148 ns) were somewhat shorter than those for the relaxed plasmids (< $\tau$ >=160 ns). This suggests that the relaxed plasmids were shielded more efficiently from water. The anisotropy decay data also showed somewhat shorter slow rotational correlation times for supercoiled plasmids (288 ns) than for the relaxed plasmids (355 ns). The presence of two rotational correlation times suggests that RuBD reveals both the bending and torsional motions of the plasmids. These results indicate that RuBD can be useful for studying both the bending and torsional dynamics of mucleic acids.

• Journal of the Korean Society of Costume
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• v.53 no.5
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• pp.111-124
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• 2003

The purpose of this study is to analyze how the women´s fashion with the design elements(silhouette, material, color, detail and trimming) of androgynous image which has appeared on our specialized fashion magazine from 1986 through 2000. As a result of this study I drew the following conclusion. 1. The bon silhouette led the market in the first stage of mid 1980. The wool and leather with the masculine image, cotton and soft material with unisex image were used to express the androgynous image. The dark and mono tone with the masculine image were used a lot in color. In women´s fashion the minimalism style with simple image was expressed escaping from the decoration, in which the detail and trimming was not found as in men´s wear. 2. It showed that more and more feminine image was accepted in the second stage of early 1990. Women´s wear silhouette with the androgynous image has changed from masculine box silhouette boomed in the first stage to hourglass silhouette and slim silhouette. The wool and leather were used a lot as the materials in the first stage but the usage of the cotton with unisex image and soft texture were getting increased. The main colors were the black and the blue but the usage of the white and the red were on the increase showing the range of the use was extending. In the meantime, the detail and trimming were hardly used like in the first stage. 3. In the third stage of the late 1990, the silhouette has changed to slim style. The wool and leather were mainly used as the materials but the cotton and silk were on the increase showing that the materials of the feminine image were used in the women´s fashion with the androgynous image as well as the materials of masculine image. In color, the black and the white of the masculine image were used increasingly by the effect of the minimalism and the usage of the colors were various for the rising frequency of the trend colors usage.

• The Journal of Korean Physical Therapy
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• v.21 no.1
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• pp.65-71
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• 2009

Purpose: Numerous investigators demonstrated that adaptative changes were induced by motor skill acquisition in the central nervous system. We investigated the changes of neuroelectric potential following motor learning with serial reaction time task in young healthy subjects, using electroencephalography (EEG). Methods: Twelve right-handed normal volunteers were recruited, who have no history of neurological dysfunction and were given to written the informed consent. All subjects were assigned to flex to extend the wrist joint or flex the thumb for pressing the matched button as quickly and accurately as possible, when one of five colored lights was displayed on computer screen (red, yellow, green, blue, white). EEG was measured, whenfive types simulations ware presented randomly with equal probabilities of 20% in total 200 times at the pre and post test. And they were scheduled for 30 minutes practice session during two consecutive days in the laboratory. Results: The results showed that the reaction time at the post test was significantly reduced, compared to one of the pre test in serial reaction time task. In EEG map analysis, the broaden bilateral activation tended to be changed to the focused contralateral activation in the frontoparietal area. Conclusion: These findings showed that acquisition of motor skill led to product more fast motor execution, and that motor learning could change cortical activation pattern, from the broaden bilateral activation to the focused contralateral activation. Thus we concluded that the adaptative change was induced by motor learning in healthy subjects.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6491-6499
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• 2015

Background: Red-fleshed sweet orange juice (ROJ) comes from a new variety of citrus cultivated in Brazil that contains high levels of ${\beta}$-carotene and lycopene, and similar amounts of hesperidin (HSP) and nutrients, equivalently to blond orange juice (BOJ). Such bioactive compounds are associated with chemopreventive actions in several cancer cell lines. The purpose of this study was to examine the cytotoxicity, cell cycle, apoptosis, and cytokine secretion after BOJ, ROJ, and HSP treatment of a novel T acute lymphoblastic leukemia cell line, Loucy. Materials and Methods: Loucy cells were incubated for 24-h with BOJ, ROJ, and HSP, and the viability was measured using trypan blue. Cell cycling and apoptosis were assessed by propidium iodide (PI) and annexin V-FITC/PI flow cytometry, respectively. Secretion of cytokines $IL-1{\alpha}$, $IL1-{\beta}$, IL-2, IL-4, IL-6, IL-10, IL-17A, $IFN{\gamma}$, $TNF{\alpha}$, $TGF{\beta}$, $MIP{\alpha}$, and $MIP{\beta}$ was determined by ELISA array. Results: BOJ and ROJ treatments promoted Loucy cell cytotoxicity. Additionally, BOJ induced cell cycle arrest in the G0/G1 phase, and decreased the cell accumulation in the G2/M. ROJ decreased only the G0/G1 fraction, while HSP did not change the cell cycle. BOJ led to apoptosis in a different fashion of ROJ, while the first treatment induced apoptosis by increase of late apoptosis and primary necrotic fractions, the second increased early and late apoptosis, and primary necrotic fraction compared to positive controls. HSP had no effect on apoptosis. IL-6 and IL-10 were abrogated by all treatments. Conclusions: Taking together, these results suggest potential chemopreventive effects of BOJ and ROJ on Loucy cells.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.343-352
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• 2010

A zirconia gel/polymer hybrid nanofiber was produced in a nonwoven fabric mode by electrospinning a sol derived from hydrolysis of zirconium butoxide with a polyvinyl butyral. Results indicated that the hydroxyl groups on the vinyl alcohol units in the backbone of the polymer were involved in the hydrolysis as well as grafting the hydrolyzed zirconium butoxide. In addition, use of acetic acid as a catalyst resulted in further hydrolysis and condensation in the sol, which led to the growth of -Zr-O-Zr- networks among the polymer chains. These networks gradually transformed into a crystalline zirconia structure upon heating. The as-spun fiber was smooth but partially wrinkled on the surface. The average fiber diameter was $690{\pm}110\;nm$. The fiber exhibited a strong but broad blue photoluminescence with its maximum intensity at a wavelength of ~410 nm at room temperature. When the fiber was heat-treated at $400^{\circ}C$, the fiber diameter shrunk to $250{\pm}60\;nm$. Nanocrystals which belonged to a tetragonal zirconia phase and were ~5 nm in size appeared. A strong white photoluminescence was observed in this fiber. This suggests that oxygen or carbon defects associated with the formation of the nanocrystals play a role in generating the photoluminescence. Further heating to $800^{\circ}C$ resulted in a monoclinic phase beginning to form In the heat-treated fibers, coloring occurred but varied depending on the heating temperature. Crystallization, coloring, and phase transition to the monoclinic structure influenced the photoluminescence. At $600^{\circ}C$, the fiber appeared to be fully crystallized to a tetragonal zirconia phase.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.1025-1028
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• 2015

Background: Prostate cancer is one of the main causes of cancer death, and drug resistance is the leading reason for therapy failure. However, how this occurs is largely unknown. We therrfore aimed to study the response of DU145 cells to cisplatin. Materials and Methods: Du145 prostate cancer cells were treated with a low dose of cisplatin for 24 h and cell viability and number were determined by MTT assay and trypan blue exclusion assay, respectively. The real time polymerase chain reaction (PCR) was used to assess responses to cisplatin treatment. Results: After 24h $2{\mu}g/ml$ treatment did not result in significant reduction in cell viability or number. However, it led to enhanced cancer cell invasiveness. E-cadherin mRNA was reduced, and vimentin, Snail, Slug, metalloproteinase 9 (MMP9) mRNA expression increased significantly, a feature of epithelial-mesenchymal transition (EMT). Conclusions: Short time low concentration cisplatin treatment leads to elevated invasiveness of DU145 cancer cells and this is possibly due to EMT.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.72-77
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• 2009

Here, we demonstrate that the overexpression of the GroELS chaperone system, which assists the folding of intracellular proteins and prevents aggregation of its biological targets, can enhance the thermotolerance of Escherichia coli strains and facilitate the production of recombinant protein under thermal stress. The overexpression of GroELS led to an about 2-fold higher growth rate of E. coli XL-1 blue than control at $45^{\circ}C$ and induced the growth of the strain even at $50^{\circ}C$, although the growth was not sustained in the second-round culture. The effect of GroELS overexpression was also effective on other E. coli strains such as JM109, $DH5{\alpha}$, and BL21. Finally, we have shown that coexpression of GroELS allows us to produce recombinant protein even at $50^{\circ}C$, a temperature at which the protein production based on E. coli is not efficient. This study indicates that the employment of the GroELS overexpression system can expand the range of environmental conditions for E. coli.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.146-146
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• 2011

The blue light emitting diode (LED) structure based on non-polar a-plane (11-20) GaN which was coated TiO2 nanoparticles using spin coating method was grown on r-plane (1-102) sapphire substrates to improve light extraction efficiency. We report on the emission and structural properties with temperature dependence of photoluminescence (PL) and x-ray rocking curves (XRC). From PL results at 13 K of undoped GaN samples, basal plane stacking fault (BSF) and near band edge (NBE) emission peak were observed at 3.434 eV and 3.484 eV, respectively. We also found the temperature-induced band-gap shrinkage, which was fitted well with empirical Varshini's equation. The PL intensity of TiO2 nanoparticles ?coated multiple quantum well (MQW) sample is decayed slower than that of no coating sample with increasing temperature. The anisotrophic strain and azimuth angle dependence in the films were shown from XRC results. The full width at half maximum (FWHM) along the GaN [11-20] and [1-100] directions were 564.9 arcsec and 490.8 arcsec, respectively. A small deviation of FWHM values at in-plane direction is attributed to uniform in-plane strain.