• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1063-1068
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• 2002

Polyimide/silica(PI/silica) hybrid materials having physical or chemical bonds between the PI and silica network were prepared using sol-gel process through hydrolysis and polycondensation of tetraethoxysilane with the polyamic Acid(PAA) or end-capped PAA solution. PAA solution was synthesized by ring opening reaction of pyromellitic dianhydride and oxydianiline monomers in dimethyl acetamide solution. End-capped PAA solution was synthesized by the addition of 3-aminopropyltriethoxysilane in PAA solution. PI/silica hybrid samples were characterized by infrared spectroscopy, differential thermogravimetry, X-ray diffractometry, scanning electron microscopy, and tensile tester. It has been demonstrated that the properties of hybrid samples were affected by the silica content and the bond type between PI and silica.

• Geotechnical Engineering
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• v.7 no.4
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• pp.75-88
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• 1991

A lot of landslides has occurred in rainy seasons beginning at June through September in Korea, where about 70 percent of the total area is mountaneous. Piles can be used as one of the most useful methods to stabilize such landslides. When a row of piles is installed in soil undergoing lateral movement such as landslides, the soil across the open space between the piles can be retained by the arching action of the soil. For the purpose to establish a reasonable design method for stabilizing piles, a method for stability analysis of the slope containing stabilizing piles is presented, using the theoretical equation of the lateral force acting on the piles in soil undergoing lateral movement. In particular, the theoretical equation is arranged by applying the coefcients of lateral force as a simple equation. And also the differential equations proposed in the previous studies for the pile-stability analysis are modified, assumming that the piles above the sliding surface shall be subjected to the lateral reaction from soil in proportion to the pile deflection. Finally, to investigate the effect of stabilizing piles against landslides, an existing landslide slope in Korea is adopted as an example.

• Journal of Electrochemical Science and Technology
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• v.10 no.4
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• pp.361-372
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• 2019

The silver nanoparticles/polyaniline/reduced graphene oxide nanocomposite modified glassy carbon electrode (Ag/PANI/RGO/GCE) was prepared by the electrochemical method. The Ag/PANI/RGO nanocomposite was characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, X-ray diffraction (XRD), and electrochemical impedance spectroscopy (ESI). Two electrochemical techniques namely differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were used to the electrochemical behaviors investigation of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The Ag/PANI/RGO/GCE exhibited remarkable electrocatalytic activity towards the oxidation reaction of AA, DA, and UA in Britton-Robinson (BR) solution (pH=4.0). Under the optimal conditions, the determinations of AA, DA, and UA were accomplished using DPV. AA-DA and DA-UA peak potential separations were 130 and 180 mV, respectively. For simultaneous detection, the linear response ranges were in the two concentration ranges of 0.05-0.8 mM and 2.0-16.0 mM with detection limit 0.412 μM (S/N = 3) for AA, 0.7-90.0 μM and 90.0-1000.0 μM with detection limit 0.023 μM (S/N = 3) for DA, and 0.8-70.0 μM and 70.0-1000.0 μM with detection limit 0.050 μM (S/N = 3) for UA. This modified electrode showed good sensitivity, selectivity, and stability with applied to determine AA, DA, and UA in human urine and drug.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.5
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• pp.753-762
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• 2020

Objective: The aim of the present study was to determine the effect of supplementing pasture-finished steers with corn silage on the expression level of the calpain system proteins and beef tenderization. Methods: Thirty Braford steers grazing on summer pasture were used for the study. For 120 days fifteen animals were supplemented with corn silage at 1% of body weight per head per day (Suppl) whereas the remaining 15 steers only received pasture (Contr). Carcass and meat traits were evaluated and compared between groups. Gene expression and activities of proteases (calpain 1 and calpain 2) and inhibitor (calpastatin) were measured using real-time polymerase chain reaction and casein zymography. Results: Carcass and meat traits were significantly different between feeding systems. Supplemented steers showed higher hot carcass weight (p<0.01), fat content (p = 0.02), and Warner-Bratzler shear force (p = 0.03). Furthermore, the control group showed higher protease:inhibitor ratios, at mRNA (p = 0.01) and protein levels (p<0.10). Warner-Bratzler shear force and mRNA calpains:calpastatin ratio were associated in both feeding systems (p<0.01). Conclusion: Based on the results obtained in the study, beef tenderness differences among finishing strategies could be modulated through differential expression of the calpain system proteins.

• Biomedical Science Letters
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• v.10 no.3
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• pp.195-202
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• 2004

Lung cancer is a leading cause of cancer death worldwide; however, despite major advances in cancer treatment during the past two decades, the prognostic outcome of lung cancer patients has improved only minimally. This is largely due to the inadequacy of the traditional screening approach of diagnosis in lung cancer, which detects only well­established overt cancers and fails to identify precursor lesions in premalignant conditions of the bronchial tree. In recent years this situation has fundamentally changed with the identification of molecular abnormalities characteristic of premalignant changes; these concern tumour suppressor genes, loss of heterozygosity at crucial sites and activation of oncogenes. Basic knowledge at the molecular level has extremely important clinical implications with regard to early diagnosis, risk assessment and prevention, and therapeutic targets. In this study we used a 'cap-finder' subtractive hybridization method, 'long distance' polymerase chain reaction (PCR), streptavidin magnetic beads mediated subtraction, and spin column chromatography to detect differential expression genes of human small cell lung carcinoma. We have now isolated ninety two genes that expressed differentially in the human small cell lung carcinoma cells and analyzed of 12 clones with sequencing, nine cDNAs include tapasin (NGS-17) mRNA, BC200 alpha scRNA, chromosome 12q24 PAC RPCI3-462E2, protein phosphatase 1 (PPPICA), translocation protein 1 (TLOC1), ribosomal protein S24 (RPS24) mRNA, protein phosphatase (PPEF2), cathepsin Z, MDM2 gene and three novel genes. They may be oncogenesis­related proteins.

• Korean Journal of Biological Psychiatry
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• v.6 no.1
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• pp.67-73
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• 1999

The cAMP-dependent protein kinase(PKA) is an intracellular enzyme with serine-threonine kinase activity that plays a key role in cell growth, differentiation, and apoptosis in eukaryotes. In order to understand the PKA signal transduction pathway regulating cell life cycle and identify its role, we focused on the characterization of up-/down-regulated genes by PKA using the differential display polymerase chain reaction. Seven differentially expressed sequence tags(DEST) have been obtained. Among these DESTs, 2 DESTs were homologous to the sequence of genes from BLAST search result. KC1-5 DEST that was up-regulated in A123.7 cells was highly corresponded to mouse apoptosis-related gene(MA-3) or mouse mRNA for topoisomerase inhibitor suppressed(TIS). MA-3 was induced in various types of apoptosis, specially in NGF-deprived apoptotic PC12 cells. TIS was down-regulated in the RVC lymphoma cells incubated with topoisomerase inhibitor that induces DNA strand breakages. PG1-1 DEST that was highly expressed in PC12 cells was corresponded to transposon Tn10 3'-end. Tnansposon Tn10 was up-regulated in differentiated myeloblastic ML-1 cells by 12-O-tetradecanoylphorbol-13-acetate. This study illuminates that MA-3/TIS was down-regulated by PKA activity, and transposon Tn10 was up-regulated by it.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.33-36
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• 2008

The transient behavior of a passive air breathing direct methanol fuel cell (DMFC) operated on vapor-feeding mode is studied in this paper. It generally takes 30 minutes after starting for the cell response to come to its steady-state and the response is sometimes unstable. A mathematical dynamic one-dimensional model for simulating transient response of the DMFC is presented. In this model a DMFC is decomposed into its subsystems using lumped model and divided into five layers, namely the anodic diffusion layer, the anodic catalyst layer, the proton exchange membrane (PEM), the cathodic catalyst layer and the cathodic diffusion layer. All layers are considered to have finite thickness, and within every one of them a set of differential-algebraic governing equations are given to represent multi-components mass balance, such as methanol, water, oxygen and carbon dioxide, charge balance, the electrochemical reaction and mass transport phenomena. A one-dimensional, isothermal and mass transport model is developed that captures the coupling between water generation and transport, oxygen consumption and natural convection. The single cell is supplied by pure methanol vapor from a methanol reservoir at the anode, and the oxygen is supplied via natural air-breathing at the cathode. The water is not supplied from external source because the cell uses the water created at the cathode using water back diffusion through nafion membrane. As a result of simulation strong effects of water transport were found out. The model analysis provides several conclusions. The performance drop after peak point is caused by insufficiency of water at the anode. The excess water at the cathode makes performance recovery impossible. The undesired crossover of the reactant methanol through the PEM causes overpotential at the cathode and limits the feeding methanol concentration.

• The Journal of Internal Korean Medicine
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• v.39 no.4
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• pp.772-783
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• 2018

The aims of this study were to use the Rydoraku test, electrogastrography, and enterotachography to examine the presence of familial gastric dysmotility among monozygotic twins and their mothers; to determine the relationship between the symptoms and the indexes of the Rydoraku test, electrogastrography, and enterotachography; and to observe the therapeutic reaction for each differential treatment between twins with familial gastric dysmotility. The same herbal medication (Banhasasim-tang extract three times/day and Sojuckkunbi-tang extract three times/day) was given to each twin, but the younger twin also underwent manual acupuncture on the CV 10, 12, and 13 points of the abdominal wall and electrical stimulation of both ST 36 points of the lower leg 2-3 times per week. Evaluation of the therapeutic effect was followed after six weeks. The presence of familial gastric dysmotility was shown in the autonomic nerve system and gastric muscle and was thought to be a common pathophysiology induced by genetic co-ownership. Only the younger twin showed any marked relief of the dyspeptic symptoms associated with improvement of pyloric sphincter function, which was induced by acupuncture treatment. The Rydoraku test, electrogastrography, and enterotachography results showed the presence of familial gastric dysmotility. Although Korean traditional medicine had no effect on the familiar gastric dysmotility associated with genetic influences, the acupuncture treatment had a beneficial effect on the secondary disorder of pyloric sphincter function, which is associated with the relief of dyspeptic symptoms.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.763-766
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• 2013

A synthetic peptide was prepared based on the antigenic region of Paragonimus westermani pre-procathepsin L, and its applicability for immunodiagnosis for human paragonimiasis (due to Paragonimus heterotremus) was tested using an ELISA to detect IgG4 antibodies in the sera of patients. Sera from other helminthiases, tuberculosis, and healthy volunteers were used as the references. This peptide-based assay system gave sensitivity, specificity, accuracy, and positive and negative predictive values of 100%, 94.6%, 96.2%, 100%, and 88.9%, respectively. Cross reactivity was frequently seen against the sera of fascioliasis (75%) and hookworm infections (50%). Since differential diagnosis between paragonimiasis and fascioliasis can be easily done by clinical presentation and fascioliasis serology, this cross reaction is not a serious problem. Sera from patients with other parasitoses (0-25%) rarely responded to this synthetic antigen. This synthetic peptide antigen seems to be useful for development of a standardized diagnostic system for paragonimiasis.

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.1-7
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• 1996

Thermotropic liquid-crystalline polyurethanes were synthesized by the polyaddition reaction of such para-substiuted diisocyanate monomer as 1,4-phenylene diisocyanate(1,4-PDI) and 2,5-tolylene diisocyanate(2,5-TDI), with 4,4'-bis($\omega$-hydroxyalkoxy)biphenyls(BPm: $HOC_{m}OC_{6}H_{4}C_{6}H_{4}OC_{m}H_{2m}OH$; m is the carbon number of the hydroxyalkoxy group). These polyurethanes have mesogenic biphenyl units in the main chain. Properties of polymers were studied by differential scanning calorimetry, wide-angle X-ray scattering, thermogravimetic analysis, polarizing microscopy, and infraed spectroscopy. DSC thermograms for these polymers exhibited two endothermic peaks corresponding to phase transitions of melting and isotropization. Mesomorphic behavior of the polyurethanes were also observed under the polarizing microscope. For example, polyurethane 2,5-YDI/BP5 with [$\theta$]=0.44 prepared from 2,5-TDI and BP5 exhibited a liquid crystalline phase from 194 to 205$^{\circ}C$. Infrared spectrum study indicated that the hydrogen bonding between urethane linkages affected the mesomorphism. The thermostabilities of polyurethanes 2,5-TDI/BP5 and 1,4-PDI/BP5 were measured at a heating rate of 1$0^{\circ}C$/min in air. The temperatures of 5% weight loss for 2,5-TDI/BP5 and 1,4-PDI/BP5 were 297 and 334$^{\circ}C$, respectively.