• Journal of Life Science
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• v.17 no.7 s.87
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• pp.896-904
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• 2007

Regulation mechanism of apoptosis has been known to be important for understanding the pathogenesis of a number of human diseases including cancers. The effects of $RRR-{\alpha}-tocopheryl$ succinate(vitamin E succinate, VES) on the cell viability, generation of ROS, expression of proteins involved in apoptosis, and growth of human chronic myelogenous leukemia K562 cells were analyzed in this study. VES treatment not only induced the generation of the ROS but also increased the levels of $NF-{\kappa}B$, COX-2, and $p21^{WAF1/CIP1}$ in K562 cells. It modulates the levels of pro-apoptotic proteins such as Bax provoking the apoptosis in K562 cells. The cleavage of PARP into 89 kDa was also increased upon VES treatment in a dosage-dependent manner. Induction of an apoptosis was evident by the increase of sub-Gl peak and cell shrinkage condensed chromatin in K562 cells treated with VES. It also resulted in an inhibition of tumor growth by 50% and prolonged survival of the Iymphoma-induced mice. This potentiation of VES obtained in vitro and in vivo may indicate the feasibility of more effective chemotherapy in chronic myelogenous leukemia.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.4
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• pp.292-296
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• 2000

Mechenochemical reaction by planetary type ball mill is applied to prepare $Sm_2$$Fe_{17}$$N_{x}$ permanent magnet powders. Starting from pure samarium and iron powders, the formation process of hard magnetic $Sm_2$$Fe_{17}$$N_{x}$ phase by ball milling and a subsequent solid state reaction were studied. At as-milled stage powders were found to consist of amorphous Sm-Fe and $\alpha$-Fe phases in all composition of $Sm_2$$Fe_{100-x}$(x = 11, 13, 15). The dependence of starting composition of elemental powder on the formation of Sm-Fe intermetallic compound was investigated by heat treatment of as-milled powders. When Sm concentration was 15 at%, heat-treated powder consists of mostly $Sm_2$$Fe_{17}$$N_{x}$single phase. For synthesizing of hard magnetic $Sm_2$$Fe_{17}$$N_{x}$ compound, additional nitriding treatment was carried out under $N_2$gas atmosphere at $450^{\circ}C$. The increase in the coercivity and remanence was parallel to the nitrogen content which increased drastically at first and then gradually as the nitriding time was extended. The ball-milled Sm-Fe-N powders were expected to be prospective materials for synthesizing of permanent magnet with high performance.

• Food Science and Preservation
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• v.24 no.6
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• pp.795-801
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• 2017

Aralia elata Seemann (AE) has long been used as a folk medicine for the treatment of various diseases including diabetes mellitus, anti-arthritic, and anti-gastric ulcer agent in Korea, Japan, and China. This study was performed to establish a simple and reliable HPLC/UV analytical method for determination of most active anti-hypertensive compound, a 3-O-${\alpha}$-L-rhamnopyranosyl($1{\rightarrow}$2)-${\alpha}$-L-arabinopyranosyl hederagenin 28-O-${\beta}$-D-xylopyranosyl($1{\rightarrow}6$)-${\beta}$-D-glucopyranosylester (HE) for the standardization of the shoot extract of AE as a health functional food ingredient. The quantitative analytical method of HE was optimized by HPLC analysis using reverse-phase C18 column at $40^{\circ}C$ with $H_2O$ and acetonitrile (70:30, v/v) as an isocratic mobile phase at a flow rate of 1.0 mL/min and detection wavelength of UV 205 nm. This HPLC/UV analytical method showed good specificity and high linearity in the tested range of 0.03125-2.0mg/ml with excellent coefficient of determination ($R^2$) of 0.9999. The limit of detection and limit of quantification were $12.0{\mu}g/mL$ and $36.5{\mu}g/mL$, respectively. Relative standard deviation (RSD) values of data from intra- and inter-day precision were less than 0.2% and 0.1%, respectively. These results indicate that the established HPLC/UV analytical method is very simple, specific, precise, accurate, and reproducible and thus can be useful for the quantitative analysis of HE as a functional anti-hypertensive compound in AE extract.

• Journal of Magnetics
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• v.11 no.1
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• pp.43-50
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• 2006

In this paper, the influences of microstructural and surface morphological developments on the soft magnetic properties and giant magneto-impedance (GMI) effect of the $Fe_{73.5-x}Cr_{x}Si_{13.5}B_{9}Nb_{3}Au_1$ (x = 1, 2, 3, 4, 5) alloys have been presented. It was found that the Cr addition slightly decreased the mean grain size of $\alpha-Fe(Si)$ grains. AFM results indicate a large variation of surface morphology of density and size of protrusions along the ribbon plane due to microstructural changes caused by thermal annealing with increasing Cr content. Ultrasoft magnetic properties of the nanocrystallized samples were noticeably enhanced by properly heat treatments at $T_a=540^{\circ}C$ such as an increase of the magnetic permeability and the decrease of coercivity, which is likely due to the formation of nanoscale $\alpha-Fe(Si)$ phase which reduced the magnetoelastic anisotropy of samples. Accordingly, the GMI effect was observed in the annealed samples. The correlation between the microstructure, surface morphology, and soft magnetic properties were explained by nucleation and growth model.

• Biomolecules & Therapeutics
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• v.16 no.2
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• pp.126-131
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• 2008

Immunosuppressive therapy after organ transplantation is routinely used to prevent rejection of the organ, because this decreases the risk of adverse events, infection, and malignancies. Recently, ursodeoxycholic acid (UDCA), which is isolated from the dried bile of adult Chinese bears, has been shown to reduce the incidence and severity of acute rejection of liver allograft during early phase of liver transplantation. Therefore, in this study, we investigated the effect of UDCA on the proliferation of splenocytes exposed to PMA plus ionomycin. Our results demonstrated that UDCA decreased the splenocytes' proliferation in a dose-dependent manner. The decreased cell proliferation was accompanied with the decreased secretion of cytokines such as IL-2, IFN-${\gamma}$ and TNF-${\alpha}$. In addition, the pretreatment of UDCA on splenocytes stimulated with PMA plus ionomycin decreased the mRNA levels of cytokines (IL-2, IFN-${\gamma}$ and TNF-${\alpha}$) and costimulatory molecules (B7.2 and PD-L1). These results suggest the beneficial effect of UDCA on organ transplantation by decreasing lymphocyte proliferation.

• Korean Journal of Materials Research
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• v.26 no.6
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• pp.337-341
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• 2016

Cu-30 vol% SiC composites with relatively densified microstructure and a sound interface between the Cu and SiC phases were obtained by pressureless sintering of PCS-coated SiC and Cu powders. The coated SiC powders were prepared by thermal curing and pyrolysis of PCS. Thermal curing at $200^{\circ}C$ was performed to fabricate infusible materials prior to pyrolysis. The cured powders were heated treated up to $1600^{\circ}C$ for the pyrolysis process and for the formation of SiC crystals on the surface of the SiC powders. XRD analysis revealed that the main peaks corresponded to the ${\alpha}$-SiC phase; peaks for ${\beta}$-SiC were newly appeared. The formation of ${\beta}$-SiC is explained by the transformation of thermally-cured PCS on the surface of the initial ${\alpha}$-SiC powders. Using powder mixtures of coated SiC powder, hydrogen-reduced Cu-nitrate, and elemental Cu powders, Cu-SiC composites were fabricated by pressureless sintering at $1000^{\circ}C$. Microstructural observation for the sintered composites showed that the powder mixture of PCS-coated SiC and Cu exhibited a relatively dense and homogeneous microstructure. Conversely, large pores and separated interfaces between Cu and SiC were observed in the sintered composite using uncoated SiC powders. These results suggest that Cu-SiC composites with sound microstructure can be prepared using a PCS coated SiC powder mixture.

• Journal of Preventive Medicine and Public Health
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• v.43 no.1
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• pp.9-17
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• 2010

Objectives: Parkinson's disease is one of the most common neurodegenerative diseases in the elderly population. In order to estimate the prevalence of Parkinson's disease in the community, the application of a good screening tool is essential. We evaluated the validity and reliability of a Parkinson's disease screening questionnaire and propose an alternative measure to improve its validity for use in community surveys. Methods: We designed the study in a three-phase approach consisting of a screening questionnaire, neurologic examination, and confirmatory examination. A repeated survey was administered to patients with disease detected in the community and on 150 subjects. We examined internal consistency using Cronbach's alpha test, test-retest reliability using the kappa statistic, and validity using sensitivity, specificity, and ROC curves. Unadjusted odds ratios were utilized for the estimation of weights for each questionnaire item. Results: The Cronbach's alpha of the questionnaire was 0.708. The kappa statistic for test-retest reliability was good to generally fair in most of the items. When newly proposed weighting scores were used, the optimum cut-off value was 7/8. When cut-off value was 5/6 for surveying prevalence in a community, the sensitivity was 0.98, and the specificity was 0.61, with simultaneous improvement in reliability. Conclusions: We recommend 5/6 as the ideal cut-off value for the survey of PD prevalence in community. This questionnaire designed for the Korean community could help future epidemiologic studies of PD.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.6
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• pp.591-597
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• 2001

Ti alloy is used for essential parts of aircraft for high temperature environment. Although Ti alloy has excellent performance in regard to mechanical properties, it is difficult ot find fatigue cracks by nondestructive ultrasonic inspection due to its two-phase microstructure, which consists of hard alpha and beta phases. Sound energy reflected from microstructural features in the component produces a background inspection noise which is seen even when no defects are present. This noise can inhibit the detection of critical internal defects such as pores cracks or inclusions. To obtain fundamental data on ultrasonic inspection of Ti alloy, ultrasonic testing was performed using a specimen with small drill holes and ultrasonic wave propagation velocites were measured.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.282-288
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• 2006

Activity-guided fractionations led to the isolation of antitumor compound, ergosterol peroxide ($5{\alpha},\;8{\alpha}-epideoxy-24(R)-methylcholesta-6,\;22-dien-3{\beta}-ol$) from the fruiting body of Pleuratus eryngii that was cultivated artificially. This sterol structure was established by using spectroscopic methods ($^1H\;and\;^{13}C$ nuclear magnetic resonance and high resolution mass spectra). The purified compound showed a molecular formular of $C_{28}H_{44}O_3$ displaying characteristic features of epidioxy sterols. The 50% inhibitory concentrations ($IC_{50}$) of ergosterol peroxide against human lung cancer cell line (A549) and human ovarian cell line (SK-OV3) were $7{\mu}M\;and\;14{\mu}M$, respectively. In the DNA fragmentation assay, the compound showed the programmed cell death causing the chromosomal DNA fragmentation. It reveals that ergosterol peroxide arrests G1 phase of the cell division cycle.

• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.715-721
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• 2004

Hydroxyapatite (HAp)/Gelatin (GEL) homogeneous composites of four different composition ratio were prepared by the co-precipitation process with synthetic HAp and GEL as a binder, HAP/GEL composites were molding by cold isostatic pressing and were sintering by various condition in air. Crystallinity and structure of sintered HAp/GEL composites were investigated by XRD and FTIR. Also, the compressive strength and the fracture surface of sintered specimens were measured by UTM and SEM. HAp/GEL composites showed a phase transformation to partially ${\alpha}$, ${\beta}$-tricalcium phosphate at the sintered condition of 1200$^{\circ}C$ for 3 h. The porosity of sintered body was in the range of 1.2-30.2％. The compressive strength of the sintered specimens was in the range of 16.2-60.1㎫, and its strength of sintered HAp/GEL comosites was higher than expected when the porosity was considered.