• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.121-127
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• 2011

In this study, possible use of indigenous natural loess (Hwangtoh) as a new binding material via geopolymerization process is examined. Hwangtoh pastes with four different mix proportions of varying alkali liquid concentrations (6 M, 8 M) and the constituents of the binder as well as the alkali liquid at a constant liquid-to-binder ratio of 0.55 were prepared. Analysis of the natural loess (Hwangtoh) paste was carried out as follows : 1) Measurement of compressive strength and weight of cubic specimens versus curing time; 2) Analysis by X-ray diffraction (XRD) and scanning electron microscope (SEM) about reaction product; 3) Porosity analysis of hardened Hwangtoh paste. The result showed that it is possible to prepare Hwangtoh paste with 29.1 MPa at the age of 7 day by using alkali solution (made as 1 : 4.5 the mass ratio of liquefied $Na_2SiO_3$ and NaOH solution and applying the curing temperature of $60^{\circ}C$). Compressive strength development with respect to the degree of moisture evaporation from the paste seems to be independent of curing temperature. Therefore, it seems that higher early strength of the paste specimens cured at higher temperature can be attributed to both higher rate of reaction and moisture evaporation.

• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.971-976
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• 2008

Purpose : Surveillance for detecting and managing latent tuberculosis infection (LTBI) is a key component of tuberculosis control. The classic surveillance tool, the tuberculin skin test (TST), may have some limitations when used in the Bacillus Calmette-$Gu{\acute{e}}rin$ (BCG)-vaccinated population. The object was to perform a blood test $QuantiFERON^{(R)}$-TB Gold In Tube (QFT-G IT) based on the detection of interferon-$\gamma$ ($IFN-{\gamma}$) released by T cells in response to Mycobacterium tuberculosis-specific antigens, and to compare the efficacy of this new diagnostic tool for LTBI with that of TST. Methods : For six months, between October 1, 2006 and April 30, 2007, data were collected from 111 patients under 15 years of age at Severance Children's Hospital. TST and QFT-G IT tests were performed with children with or without contact histories of tuberculosis. In addition to these tests, we examined comparative data from 29 adults who had tuberculosis, to detect false negative rates in the QFT-G IT method. Results : Thirty-three children had household contact histories. In this group, 15% and 42% of cases were found to be positive using the QFT-G IT assay and TST, respectively. Agreement was low between these two tests (${\kappa}=0.39$). In the adult active tuberculosis group, the QFT-G IT false negative rate defined as a positive culture and a negative QFT-G IT result was 12.5%. Conclusion : In diagnosing LTBI in children, the usefulness of a whole-blood $IFN-{\gamma}$ assay employing TB-specific antigens will be revealed only by examining additional longitudinal clinical data; this study serves as a starting point in that process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5C
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• pp.393-402
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• 2012

In this study, we propose a signal processing algorithm to measure the arousal level of a human subject using a PPG(Photoplethysmography) sensor. From the measured PPG signals, the arousal level is determined by PPI(Pulse to Pulse Interval) and discrete-time signal processing. We ran psychophysical experiments displaying visual stimuli on TV display while measuring PPG signal from a finger, where the nature landscape scenes were used for restorative effect, and the urban environments were used to stimulate the stress. However, the measured PPG signals may include noise due to subject movement and measurement error, which results in incorrect detections. In this paper, to mitigate the noise impact on stimulus detection, we propose a detecting algorithm using digital signal processing methods and statistics of measured signals. A filter is adopted to remove a high frequency noise and adaptively designed taking into account the statistics of the measured PPG signals. Moreover we employ a hysteresis method to reduce the distortion of PPI in decision of emotional. Via experiment, we show that the proposed scheme reduces signal noise and improves stimulus detection.

• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.239-247
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• 2006

Background: Culture filtrate proteins secreted by mycobacteria are thought to play an important role in inducing protective immunity and to develop new methods for diagnosing tuberculosis. Methods: A culture filtrate protein of M. avium that was strongly reactive with goat antiserum against M. intracellulare was constructed. Its homologous protein (TB-14) in M. tuberculosis was cloned, expressed and purified. The inductions of IFN-${\gamma}$ stimulated with $10{\mu}g$ of TB-14 recombinant protein and $10{\mu}g$ PPD were estimated by using whole bloods from seven PPD (-) subjects, seven PPD (+) healthy volunteers and nine tuberculosis patients. Results: M. avium culture filtrate protein was confirmed as a hypothetical protein that was termed contig 116. A novel 14-kDa recombinant protein (TB-14) of M. tuberculosis was composed of 148 amino acids, including 30 amino acids of the signal peptide, and it showed 78% homology with M. avium. In the PPD (+) healthy volunteers, recombinant TB-14 protein strongly induced the secretion of IFN-${\gamma}$ in whole blood cultures. Conclusion: These results suggest that TB-14 recombinant protein might play an important role in inducing cell-mediated immunity against tuberculosis. Furthermore, TB-14 protein antigen and its antiserum will be available for the development of new diagnostic tools for tuberculosis.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.383-388
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• 1994

Chaotic analysis of EEG signal responding to auditory stimulus with various carrier frequency and constant triggering frequency is given in this paper. The EEG signal is obtained from the digital 12channel EEG system made in our laboratory. The carrier frequency is varied from 1 kHz to 3 kHz by 0.5 kHz step. Chaos analysis such as pseudo phase space portrait, Lyapunov exponent, and so on is done on the auditory stimulated evoked potential. This result is found to be quite consistent with the well known results from the psychological perception theory.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.107-112
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• 2003

The Chunma requires a simple pre-treatment, due to the inconveniences of preservation, toxicities, and pungencies in intact state. Various steaming conditions were examined to establish the anti-oxidative characteristics of Chunma using the Response Surface Methodology (RSM). Total phenolics and electron-donating ability were optimal at 94.43 and $101.67^{\circ}C$ for 42.38 and 41.09 min, respectively. Anti-oxidative (Al) and nitrite-scavenging ability were optimal at $100^{\circ}C$ for 40 min. Optimal steaming conditions were determined as 96{\sim}107{\circ}C$ for $28{\sim}46min$ min, almost identical to the predicted conditions of $100^{\circ}C$, 40 min determined using the superimposed contour map. Anti-oxidative activities (AI) under the optimal conditions were $95.9%{\sim}115.6%$ of those determined under predicted conditions, an indication of the high reliability of the calculated values.

• Journal of The Korean Association For Science Education
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• v.37 no.1
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• pp.63-75
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• 2017

The purpose of this study is to explore the effect of responsive teaching on students' productive argumentation practice. The participating students predicted the results of an activity to measure in which location on the body (the head, spine, or back of the hand) they would feel a cellphone's vibrations faster. They then engaged in the activity and built an argument to justify it. We interviewed the teacher to understand her thoughts regarding what was expected in the class. We also recorded and transcribed the class and the interview, for use in the analysis of the students' epistemological framing and the teacher's responsive practice in small group argumentation. We discovered that the teacher intervened in the groups with questions that elicited students' thoughts as starting points for her responsive practice. Her eliciting questions led the students to talk about their ideas, supporting their engagement in the argumentation. The teacher's understanding of the argumentation lesson and her behavior to understand the students' ideas reflected her productive framing, which led her to elicit students' ideas and to support their active interaction during the small-group argumentation. She presented rebuttals against students' ideas, engaging in the argumentation as another participant, not as an evaluator. This supported the equality of intellectual authority in the group and showed students how to engage in the argumentation, supporting students' productive framing. As a result of these responsive teaching practices, the students shifted their epistemological framing, resulting in productive argumentation practice. The results of this study will contribute to developing teachers' responsive teaching strategies to support students' productive framing in science classrooms.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.211-218
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• 2021

The purpose of this study is to develop how to extract essential oil from heartwood of chamaecyparis obtusa and commercialize eco-friendly products using essential oil. Manufacturing process consisted of 8 steps: pulverization, input, pretreatment, extraction(steam distillation), steam emission, cooling, separation, aging. Through the method developed in this study, chamaecyparis obtusa oil with excellent quality in antibacterial effect can be extracted with high productivity. Also, chamaecyparis obtusa spray using this oil had good antibacterial and deodorant effects, and got no irritation results in the clinical test. To commercialize spray, we built a commercial website and performed consumer survey on the site. The survey results showed that respondents had positive attitude toward the products and their messages in the site. When the production standardization through precise quality control and the optimization of composition ratio are accomplished, this study will contribute to commercialize various types of cosmetics and quasi-drugs.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.223-235
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• 2000

Background: Liquid ventilation is associated with decreased inflammatory response in an injured lung. This study was performed to investigate if whether perfluorocarbon(PFC) can decrease chemokine expression in airway epithelial cells. Methods: A549 cells were used for airway epithelial cells and perfluorodecalin for PFC. To expose cells to PFC, lower chamber of Transwell$^{(R)}$plate was used. This study was performed in two parts. In the first part, we examined whether PFC could decrease chemokine expression in airway epithelial cells through inhibition of other inflammatory cells. Peripheral blood mononuclear cells(PBMC's) were isolated and stimulated with lipopolysaccharide(LPS, 10 ${\mu}g/mL$) for 24 hours with or without exposure to PFC. Then A549 cells were stimulated with conditioned media(CM) containing the culture supernatants of PBMC. After 24 hours, the expressions of interleukin-8(IL-8) and RANTES were measured. In the second part of the study, we studied whether PFC could directly suppress chemokine expression in airway epithelial cells. A549 cells were stimulated for 24 hours with interleukin-l$\beta$ and/or tumor necrosis factor-$\alpha$ with or without exposure to PFC, and then the chemokine expression was measured. Northern analysis was used to measure the mRNA expression, and ELISA was used for immunoreactive protein measurements in culture supernatant. Results: 1. IL-8 and RANTES mRNA expression and immunoreactive protein production were increased significantly by CM from LPS-stimulated PBMC in A459 cells compared to with CM from unstimulated PBCM (p<0.05), but exposure of PFC had no significant effect on either mRNA expression or immunoreactive protein expression. 2. IL-8 and RANTES mRNA expression and immunoreactive protein production were increased significantly by IL-1$\beta$ and TNF-$\alpha$ in A549 cells(p<0.05), but exposure of PFC had no significant effect on neither either mRNA expression nor immunoreactive protein production. Conclusion : Decreased chemokine expression of airway epithelial cells may not be involved in decreased inflammatory response observed in liquid ventilation. Further studies on possible mechanisms of decreased inflammatory response are warranted.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.522-534
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• 1995

Background: In the pathogenesis of acute lung injury induced by lipopolysaccharide(LPS), oxygen radiclls are known to be involved in one part. Superoxide dismutase(SOD) protects oxygen radical-induced tissue damage by dismutating superoxide to hydrogen peroxide. In eukaryotic cells, two forms of SOD exist intracellularly as a cytosolic, dimeric copper/zinc-containing SOD(CuZnSOD) and a mitochondrial, tetrameric manganese-containing SOD(MnSOD). But there has been little information about SOD gene expression and its regulation in pulmonary alveolar macrophages(PAMs). The objective of this study is to evaluate the SOD gene expression induced by LPS and its regulation in PAMs of rat. Method: In Sprague-Dawley rats, PAMs obtained by broncholaveolar lavage were purified by adherence to plastic plate. To study the effect of LPS on the SOD gene expression of PAMs, they were stimulated with different doses of LPS($0.01{\mu}g/ml{\sim}10{\mu}g/ml$) and for different intervals(0, 2, 4, 8, 24hrs). Also for evaluating the level of SOD gene regulation actinomycin D(AD) or cycloheximide(CHX) were added respectively. To assess whether LPS altered SOD mRNA stability, the rate of mRNA decay was determined in control group and LPS-treated group. Total cellular RNA extraction by guanidinium thiocyanate/phenolfchlorofonn method and Northern blot analysis by using a $^{32}P$-labelled rat MnSOD and CuZnSOD cDNAs were performed. Results: The expression of mRNA in MnSOD increased dose-dependently, but not in CuZnSOD. MnSOD mRNA expression peaked at 8 hours after LPS treatment. Upregulation of MnSOD mRNA expression induced by LPS was suppressed by adding AD or CHX respectively. MnSOD mRNA stability was not altered by LPS. Conclusion: These findings show that PAMs of rat could be an important source of SOD in response to LPS, and suggest that their MnSOD mRNA expression may be regulated transcriptionally and require de novo protein synthesis without affecting mRNA stability.