• Korean Journal of Materials Research
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• v.13 no.2
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• pp.120-125
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• 2003

A low melting borosilicate glass frit was used as an adhesion promoter, which enables $MnWO_4$to be sintered with in a reasonable sintering temperature range ($800∼1000^{\circ}C$). The glass was evaluated for glass transition temperature ($Τ_{g}$ X) and thermal expansion coefficient($\alpha$). Mechanical property (Vickers hardness), grain growth, the comparison of lattice parameter and pore distribution of sintered $MnWO_4$ with the frit were methodically discussed. As sintering temperature increased, a typical liquid phase sintering showed the rapid grain growth and high densification of X$MnWO_4$grain, improvement of hardness (until $920^{\circ}C$) and different pore size distribution. Resistance of sintered $MnWO_4$varied from 450k$\Omega$ to 8.8M$\Omega$ under the measuring humidify ranging from 30 to 90%. Thus, the results will contribute to the application of glass frit containing sensor materials and their future use.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.383-389
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• 2015

The use of zoysiagrass (Zoysia japonica Steud.) in the transition zone is limited because of a lack of cold hardiness although zoysiagrass has many advantages compared to other warm-season and cool-season grasses. Late-fall N fertilization is often applied for darker green color of turfgrass in early spring and more extensive root growth without rapid top growth. The objective of the study was to evaluate the effects of late fall N application and turf cover for zoysiagrass spring green-up. Clear polyvinyl chloride (PVC) film was used for turf cover. The amount of N applied were 5 and $10g\;N\;m^{-2}$ for the low and high N rate treatments, respectively. Covered zoysiagrass had greater turfgrass color and quality in early spring than non-covered zoysiagrass. The high N rate had 0.6 to 2.3 greater turfgrass quality than the low N rate on 7 of 9 rating dates. Slow-release N as late fall fertilization is more effective for turfgrass color and quality than fast-release N in spring. Turf cover could reduce the period of yellow zoysiagrass, and the earlier time of spring green-up could be advanced by increasing turfgrass quality and growth of zoysiagrass.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.216-217
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• 2006

A common problem in many fields of cryogenic power engineering is to apply high voltage to cold parts of superconducting equipment. In many of these cases a bushing provides electrical insulation for the conductor which makes the transition from ambient temperature to the cold environment. The cryogenic high voltage bushing for the 154kV, 100MVA high temperature superconducting(HTS) transformer is described. The bushing is energized with the line-to-ground voltage between the coaxial center and outer surrounding conductors, in the axial direction there is a temperature difference from ambient to about 77 K. For the insulation design of cryogenic bushing, the arrangement of condenser cone and electrical insulation characteristics of GFRP, Air, $LN_2$ and $GN_2$ were discussed in this paper.

• Molecules and Cells
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• v.40 no.2
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• pp.143-150
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• 2017

Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.85-90
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• 2021

The gamma irradiation was on to Poly(butylene sebacate-co-terephthalate) (PBSeT), Poly(butylene adipate-co-terephthalate) (PBAT), Poly(lactic acid) (PLA) and casting polypropylene (CPP) at dose levels from 0 to 50 kGy. The properties of gamma irradiated samples were analyzed using DSC, TGA, UTM and FT-IR spectra. The mechanical and thermal properties of PBSeT and PBAT after gamma irradiation were less affected than CPP. The tensile strength and elongation of PBSeT was not affected by gamma irradiation, while these of PBAT, PLA and CPP were significantly decreased at 50 kGy gamma-ray dose. The thermal stability of PBSeT, PBAT, PLA and CPP showed a similar tendency to tensile strength. The glass transition temperature(T_g) and melting temperature(T_m) of PBSeT and PBAT were not altered by increasing gamma-ray dose, while these of PLA and CPP decreased. The chemical composition of all samples was not modified by gamma irradiation, and it was confirmed by FT-IR spectra. Based on mechanical and thermal stability studies of gamma irradiation on bioplastics, tested biodegradable packaging materials showed a potential to be used in sterilization process up to 35 kGy.

• Journal of The Korean Astronomical Society
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• v.24 no.1
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• pp.71-94
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• 1991

With the 14 m radio telescope at DRAO and the 4 m at Nagoya University, we have made detailed maps of $^{12}CO$ and $^{13}CO$ emissions from two Barnard objects B133 and B134 in the $J=1{\rightarrow}O$ rotational transition lines. Usual LTE analyses of the CO observations led us to determine the distribution of column densities over an entire area encompassing both globules. Total gas masses estimated from the column density map are $90\;M_{\odot}$ and $20\;M_{\odot}$ for B133 and B134, respectively. The radial velocity of B133 is red shifted with respect to B134 by $0.8\;km\;s^{-1}$, which is too lagre to bind the two clouds as a binary system. We have shown that the usual stability analysis based on the simplified version of virial theorem with the second time-derivative of the moment of inertia term $\ddot{I}$ being ignored could mislead us in determining whether a given cloud eventually collapses or not. The lull version of the scalar virial theorem with the $\ddot{I}$ term is shown to be useful in following up the time-dependent variations of the cloud size R and its streaming velocity $\dot{R}$ as functions of time. Results of our stability analysis suggest that B133 will eventually collapse in $(2{\sim}4){\times}10^6$ years.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5489-5494
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• 2013

In the current study we aimed to show the common YMDD motif mutations in viral polymerase gene in chronic hepatitis B patients during lamivudine and adefovir therapy. Forty-one serum samples obtained from chronic hepatitis B patients (24 male, 17 female; age range: 34-68 years) were included in the study. HBV-DNA was extracted from the peripheral blood of the patients using an extraction kit (Invisorb, Instant Spin DNA/RNA Virus Mini Kit, Germany). A line probe assay and direct sequencing analyses (INNO-LIPA HBV DR v2; INNOGENETICS N.V, Ghent, Belgium) were applied to determine target mutations of the viral polymerase gene in positive HBV-DNA samples. A total of 41 mutations located in 21 different codons were detected in the current results. In 17 (41.5%) patients various point mutations were detected leading to lamivudin, adefovir and/or combined drug resistance. Wild polymerase gene profiles were detected in 24 (58.5%) HBV positive patients of the current cohort. Eight of the 17 samples (19.5%) having rtM204V/I/A missense transition and/or transversion point mutations and resistance to lamivudin. Six of the the mutated samples (14.6%) having rtL180M missense transversion mutation and resistance to combined adefovir and lamivudin. Three of the mutated samples (7.5%) having rtG215H by the double base substituation and resistance to adefovir. Three of the mutated samples (7.5%) having codon rtL181W due to the missense transversion point mutations and showed resistance to combined adefovir and lamivudin. Unreported novel point mutations were detected in the different codons of polymerase gene region in the current HBV positive cohort fromTurkish population. The current results provide evidence that rtL180M and rtM204V/I/A mutations of HBV-DNA may be associated with a poor antiviral response and HBV chronicity during conventional therapy in Turkish patients.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.79-84
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• 1993

This paper describes the development of lithium rechargeable cell. $LiCoO_2$ is recently recognized as a suitable cathode active material of a high voltage, high energy lithium rechargeable batteries because $Li^+$ ion can be electrochemically deintercalated/intercalated from/to $Li_xCoO_2$. The transition metal oxide of $LiCoO_2$ was investigated for using as a cathode active material of 4V class Li rechargeable cell. $LiCoO_2$ cathode was prepared by using a active material of 85 wt%, graphite powder of 12 wt% as a conductor and poly-vinylidene fluoride of 3 wt% as a binder. The electrochemical and charge/discharge properties of $LiCoO_2$ were investigated by cyclic voltammetry and galvanostatic charge/discharge. The open circuit voltage of prepared $LiCoO_2$ electrode exhibited approximately. potential range between 3.32V and 3.42V. During the galvanostatic charge/discharge, $LiCoO_2/Li$ cell showed stable cycling behavior at scan rate of 1mV/sec and potential range between 3.6V and 4.2V. Also its coulombic efficiency as function of cycling was 81%~102%. In this study the $LiCoO_2/Li$ cell showed the available discharge capacity of 90.1 mAh/g at current density of $1mA/cm^2$ and cell discharge voltage range between 3.6V~4.2V.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.531-535
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• 2015

Vasculogenic mimicry (VM) refers to the unique ability of highly aggressive tumor cells to mimic the pattern of embryonic vasculogenesis, which was associated with invasion and metastasis. The grape seed proanthocyanidins (GSPs) had attracted much attention as a potential bioactive anti-carcinogenic agent. However, GSPs regulation of VM and its possible mechanisms in a triple-negative breast cancer cells (TNBCs) remain not clear. Therefore, we examined the effect of GSPs on VM information in HCC1937 cell model. In this study, we identified the VM structure via the three-dimensional (3D) matrix in vitro. Cell viability was measured using the CCK8 assay. The effects of GSPs on human triple-negative breast cancer cells (TNBCs) HCC1937 in terms of related proteins of VM information were determined using western blot analysis. In vitro, the tubular networks were found in highly invasive HCC1937 cells but not in the non-invasive MCF-7 cells when plated on matrigel. The number of vascular channels was significantly reduced when cells were exposed in GSPs ($100{\mu}g$/ml) and GSPs ($200{\mu}g/mL$) groups (all p<0.001). Furthermore, we found that treatment with GSPs promoted transition of the mesenchymal state to the epithelial state in HCC1937 cells as well as reducing the expression of Twist1 protein, a master EMT regulator.GSPs has the ability to inhibit VM information by the suppression of Twist1 protein that could be related to the reversal of epithelial-to-mesenchymal (EMT) process. It is firstly concluded that GSPs may be an p otential anti-VM botanical agent for human TNBCs.

• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.200-209
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• 2023

Patients with non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) amplification or sensitive mutations initially respond to the tyrosine kinase inhibitor gefitinib, however, the treatment becomes less effective over time by resistance mechanism including mesenchymal-epithelial transition (MET) overexpression. A therapeutic strategy targeting MET and EGFR may be a means to overcoming resistance to gefitinib. In the present study, we found that picropodophyllotoxin (PPT), derived from the roots of Podophyllum hexandrum, inhibited both EGFR and MET in NSCLC cells. The antitumor efficacy of PPT in gefitinib-resistant NSCLC cells (HCC827GR), was confirmed by suppression of cell proliferation and anchorage-independent colony growth. In the targeting of EGFR and MET, PPT bound with EGFR and MET, ex vivo, and blocked both kinases activity. The binding sites between PPT and EGFR or MET in the computational docking model were predicted at Gly772/Met769 and Arg1086/Tyr1230 of each ATP-binding pocket, respectively. PPT treatment of HCC827GR cells increased the number of annexin V-positive and subG1 cells. PPT also caused G2/M cell-cycle arrest together with related protein regulation. The inhibition of EGFR and MET by PPT treatment led to decreases in the phosphorylation of the downstream-proteins, AKT and ERK. In addition, PPT induced reactive oxygen species (ROS) production and GRP78, CHOP, DR5, and DR4 expression, mitochondrial dysfunction, and regulated involving signal-proteins. Taken together, PPT alleviated gefitinib-resistant NSCLC cell growth and induced apoptosis by reducing EGFR and MET activity. Therefore, our results suggest that PPT can be a promising therapeutic agent for gefitinib-resistant NSCLC.