• Journal of the Korean Vacuum Society
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• v.13 no.2
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• pp.86-91
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• 2004

Transiton-metal gallides attract wide interest as a candidate for high-temperature structural materials. In a wide composition range, in which it was known that Co-Ga alloy have CsCl (B2) crystallographic structure, a systematic study on the correlation between physical properties and electronic structures of Co-gallides was performed. $Co_{l-x}Ga$ $_{x}$ alloys ($0.35\leq$x$\leq0.55$) were prepared by arc-melting method and were annealed at $1000 ^{\circ}C$ for 48hour to increase the homogeneity. In this composition range all the prepared alloys have the CsCl (B2) structure. The chemical states and the electronic structure were studied by using x-ray photoemission spectroscopy (XPS), and x-ray absorption near-edge structure (XANES), and exhibit different physical properties depending on the composition. During the annealing, a significant oxidation has happened and all the oxygen atoms are incorporated with the Ga atoms to form a $Ga_2O_3$ phase. In a view point of electronic structure, the $Co_{l-x}Ga$ $_{x}$ alloys were formed by the Ga(p) - Co(d) hybridization.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.285-292
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• 2016

In the present study, we evaluated the in vitro wound-healing properties of two types of rice cell extracts (RCEs; prepared using ethanol and pressurized hot water extraction methods), using human dermal fibroblasts and keratinocytes. The effects of the RCEs (at 25–100 μg/ml) on cytotoxicity and cell migration were assessed. Both RCEs were not cytotoxic to the two cell types, instead increasing their proliferation by up to 25% in a dose-dependent manner compared with the controls. Furthermore, both RCEs significantly enhanced the migratory ability of the two cell types (fibroblast, 230–450%; keratinocyte, 170–350%). Additionally, we examined the effect of the RCEs on type I collagen synthesis, which is important in the wound reconstruction process. The RCEs significantly increased collagen type I mRNA and protein levels to a degree comparable to that induced by vitamin C. These results suggest the RCEs to be candidate materials for use in promoting wound healing, through their actions of increasing cell migration and accelerating wound re-epithelialization.

• Anxiety and mood
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• v.13 no.2
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• pp.74-85
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• 2017

Objective : A variety of approaches are needed to solve high suicide rates in Korean society. Although suicide prevention education has been provided for the public and suicide risk groups in Korea, a systematic discussion of simple, effective suicide prevention guidelines for the general public has yet to be made. Self-help guidelines for suicide prevention, which can help prevent suicide in at risk individuals, will be developed through expert questionnaires. Methods : In order to develop the draft guidelines, suicide prevention self-help phrases were gathered and compiled from homepages and publicity materials of domestic and international suicide prevention and related organizations. A panel of 16 suicide prevention experts conducted primary and secondary surveys using the Delphi method, which derives results from consensus among expert groups. The validity and appropriateness of the guidelines was analyzed using content validity ratios (CVR). Results : Of 33 candidate phrases selected for the suicide prevention guidelines, 9 showed high CVR after the secondary Delphi round. The highest level of support with total agreement was given to 'Do not be alone, stay with someone'. However, more than half of the panelists evaluated 14/27 of the primary Delphi round and 12/26 of the secondary Delphi round phrases as invalid. The researchers completed 10 self-help guidelines for suicide prevention, after eliminating 1 redundant phrase and including 2 additional phrases that showed relatively high CVR. Conclusion : We have developed 10 self-help guidelines for suicide prevention through the consensus of experts. Further studies on the effects of the guidleines relative to suicide rates are needed after widespread dissemination.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.172-176
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• 2002

A filamentous microorganism, strain FJ1, was isolated from completely rotten wood for the production of cellulolytic enzymes. For the production of the enzymes, cellulolsic wastes were used as carbon sources of strain FJ1 and rice straw showed higher enzyme activities than sawdust and pulp. The activities of CMCase, xylanase, $\beta$-glucosidase, and avicelase were 2.95, 5.89, 0.45, and 0.12 unit/ml by use of rice straw, respectively. To enhance production of the enzymes, the mixture substrate of rice straw and cellulosic materials were investigated as carbon sources. The highest activities of CMCase, $\beta$-glucosidase, and avicelase were found in the mixture of rice straw (0.5%, w/v) and avicel (0.5%, w/v), and the highest xylanase was obtained at the mixture ratio of 0.71%(w/v) and 0.29%(w/v). Addition of 0.1%(w/v) peptone showed enhanced production of the cellulolytic enzymes in which the activities of CMCase, xylanase, $\beta$-glucosidase, and avicelase were 19.23, 27.18, 1.28, and 0.53 unit/ml, respectively. The production of the enzymes using rice straw was efficiently induced in the presence of avicel and pulp containing cellulose. In particular, a medium composed of rice straw (0.5%, w/v) and pulp (0.5%, w/v) yielded larger cellulolytic enzymes: CMCase 24.3 unit/ml, xylanase 38.7 unit/ml, $\beta$-glucosidase 1.5 unit/ml, and avicelase 0.6 unit/ml. The filamentous microorganism, strain FJ1 utilized various cellulosic wastes as carbon sources and will be expected as a favorable candidate for biological saccharification of cellulosic wastes.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.2
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• pp.200-207
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• 2016

To add new groundwater standard, 7 candidate materials (copper, zinc, selenium, manganese, iron, chromium, aluminum) were calculated by CROWN (Chemical Ranking Of groundwater pollutaNts). Copper and zinc were selected as groundwater candidates through the process and monitored total 430 samples for 2 years with 113 groundwater sampling sites. In this study, geological distribution characteristics (igneous rock, metamorphic rock, sedimentary rock) of copper and zinc were evaluated and the geological background levels obtained by a cumulative probability distribution and pre-selection methods were compared. In the results, the highest average concentrations of the copper and zinc were observed both in the igneous rock. The detection concentration ranges of copper and zinc in 430 groundwater samples were $0.002{\sim}0.931mg\;L^{-1}$, and $0.002{\sim}32.293mg\;L^{-1}$, respectively. In addition, detection concentration ranges of copper and zinc were $0.002{\sim}0.931mg\;L^{-1}$, $0.002{\sim}32.293mg\;L^{-1}$ in the igneous rock, $0.002{\sim}0.134mg\;L^{-1}$, $0.004{\sim}7.038mg\;L^{-1}$ in the metamorphic rock and $0.002{\sim}0.008mg\;L^{-1}$, $0.003{\sim}3.948mg\;L^{-1}$ in the sedimentary rock, respectively. As a result of the background concentrations with two methods, zinc concentrations with the pre-selected method are comparatively higher than that of the others with the cumulative distribution.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9249-9258
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• 2014

Background: The encapsulation of curcumin (Cur) in polylactic-co-glycolic acid (PLGA) nanoparticles (Cur-NPs) was designed to improve its solubility and stability. Conjugation of the Cur-NPs with anti-P-glycoprotein (P-gp) antibody (Cur-NPs-APgp) may increase their targeting to P-gp, which is highly expressed in multidrugresistance (MDR) cancer cells. This study determined whether Cur-NPs-APgp could overcome MDR in a human cervical cancer model (KB-V1 cells) in vitro and in vivo. Materials and Methods: First, we determined the MDR-reversing property of Cur in P-gp-overexpressing KB-V1 cells in vitro and in vivo. Cur-NPs and Cur-NPs-APgp, in the range 150-180 nm, were constructed and subjected to an in vivo pharmacokinetic study compared with Cur. The in vitro and in vivo MDR-reversing properties of Cur-NPs and Cur-NPs-APgp were then investigated. Moreover, the stability of the NPs was determined in various solutions. Results: The combined treatment of paclitaxel (PTX) with Cur dramatically decreased cell viability and tumor growth compared to PTX treatment alone. After intravenous injection, Cur-NPs-APgp and Cur-NPs could be detected in the serum up to 60 and 120 min later, respectively, whereas Cur was not detected after 30 min. Pretreatment with Cur-NPs-APgp, but not with NPs or Cur-NPs, could enhance PTX sensitivity both in vitro and in vivo. The constructed NPs remained a consistent size, proving their stability in various solutions. Conclusions: Our functional Cur-NPs-APgp may be a suitable candidate for application in a drug delivery system for overcoming drug resistance. The further development of Cur-NPs-APgp may be beneficial to cancer patients by leading to its use as either as a MDR modulator or as an anticancer drug.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8533-8539
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• 2016

Background: B-cell chronic lymphocytic leukemia B (B-CLL), the most common type of leukemia, may be caused by apoptosis deficiency in the body. Adipose tissue-derived mesenchymal stem cells (AD-MSCs) as providers of pro-apoptotic molecules such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), can be considered as an effective anti-cancer therapy candidate. Therefore, in this study we assessed the role of tumor necrosis factor-producing mesenchymal stem cells oin apoptosis of B-CLL cells resistant to fludarabine-based chemotherapy. Materials and Methods: In this study, after isolation and culture of AD-MSCs, a lentiviral LeGO-iG2-TRAIL-GFP vector containing a gene producing the ligand pro-apoptotic with plasmid PsPAX2 and PMDG2 virus were transfected into cell-lines to generate T293HEK. Then, T293HEK cell supernatant containing the virus produced after 48 and 72 hours was collected, and these viruses were transduced to reprogram AD-MSCs. Apoptosis rates were separately studied in four groups: group 1, AD-MSCs-TRAIL; group 2, AD-MSCs-GFP; group 3, AD-MSCs; and group 4, CLL. Results: Observed apoptosis rates were: group 1, $42{\pm}1.04%$; group 2, $21{\pm}0.57%$; group 3, $19{\pm}2.6%$; and group 4, % $0.01{\pm}0.01$. The highest rate of apoptosis thus occurred ingroup 1 (transduced TRAIL encoding vector). In this group, the average medium-soluble TRAIL was 72.7pg/m and flow cytometry analysis showed a pro-apoptosis rate of $63{\pm}1.6%$, which was again higher than in other groups. Conclusions: In this study we have shown that tumor necrosis factor (TNF) secreted by AD-MSCs may play an effective role in inducing B-CLL cell apoptosis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.194-194
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• 2008

Lead oxide based ceramics, represented by PZT, are the most widely used materials for piezoelectric actuators, sensors, and transducers due to their excellent piezoelectric properties. In particular, high-performance multilayered piezoelectric ceramics for advanced electronic components have drawn great attention. In order to develop piezoelectric ceramics capable of being sintered at low temperature for multilayer piezoelectric device applications, the effect of CuO additions on the microstructures and electromechanical properties of the 0.4Pb$(Mg_{1/3}Nb_{2/3})O_3-0.25PbZrO_3-0.35PbTiO_3$ ceramics was investigated. The samples with CuO addition were synthesized by ordinary sintering technique. X-ray diffractions indicated that all samples formed a single phase perovskite structure. The addition of CuO improved the sinterability of the samples and caused an increase in the density and grain size at low temperature. The optimum sintering temperature was lowered by CuO additions. Excellent piezoelectric and electromechanical responses, $d_{33}$ ~ 663 pC/N, $k_p$ ~ 0.72, were obtained for the samples of high density with 0.1 wt% CuO addition sintered at $1050^{\circ}C$ for 4 h in air. These results show that the piezoelectric properties of PMNZT ceramics can be improved by controlling the microstructure and this system is potentially a good candidate as multilayer piezoelectric device for a wide range of electro-mechanical transducer applications.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.7-11
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• 2014

Recently, the buffer layers consisting of poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT-PSS) are extensively used to improve power conversion efficiency (PCE) of organic solar cells. However, PEDOT-PSS is not suitable for mass production of organic solar cells due to its intrinsic acid and hygroscopic properties. Moreover, because of chemical reactions between indium tin oxide (ITO) layer and PEDOT-PSS layer, the interface is not stable. For these reasons, alternative materials such as $V_2O_5$ have been developed to be an effective buffer layer. In this work, we used $V_2O_5$/Ag/ITO multilayer structure for the anode buffer layer. With variation of thickness of Ag layer, we investigated the optical and electrical properties of $V_2O_5$/Ag/ITO multi-layer films. As a result, we found that the electrical properties were improved with increasing Ag thickness while optical transmittance decreases in visible wavelength region. From the calculation of figure of merit (FOM) which is used to evaluate proper structure for transparent of optoelectronic, $V_2O_5$/Ag/ITO multilayer electrode was optimized with 4 nm thick Ag layer in optical (88% in transmittance) and electrical ($4{\times}10^{-4}{\Omega}cm$) properties. This indicates that $V_2O_5$/Ag/ITO multilayer electrode could be a candidate for the anode of optoelectronic devices.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.145-156
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• 2011

The study is to analyze voting behaviors revealed through the June 2 local elections, and to learn their implications by exploring and comparing the main factors that influence how to recognize and select a candidate. To achieve this, in-depth interviews have been conducted focusing on those who voted in the last election. The analysis shows that most respondents regard their political tendencies as moderate and make decisions on whom to vote for 2 to 3 days prior to election. It also indicates that what party candidates belong to is the highest motivation in deciding for whom to vote and they generally vote as they believe. According to the study, not only do the poll's results hardly affect their choice of candidates, but also the polls turn out significantly different from the actual results. The great gap between the polls and the actual outcome signifies that how to conduct a poll is wrong and people intend to conceal their opinions. While the media has had a decisive effect on the image of candidates, it is through promotional materials for political campaigns that the candidates' policy is recognized. The study also says that the Four-River is the most influential political issue in election. The study identifies voters' behavior specifically and in depth, and suggests some lessons to make use of for the future elections.