• Journal of The Korean Association For Science Education
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• v.44 no.1
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• pp.77-86
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• 2024

This study analyzed students' discourse and learning to investigate the impact of using Google Docs in science classes. The researcher, who is also a science teacher, conducted classes for 49 second-year middle school students. The classes included one using Google Docs and another using traditional paper worksheets covering identical content. Students' discourse collected from each class was compared and analyzed using Epistemic Network Analysis (ENA). The findings indicated that in the class using Google Docs, the proportion of discourse related to task was higher compared to the traditional class. More specifically, discourse regarding taking and uploading photos was prominent. However, such discourse did not lead to peer learning as intended by the teacher. An analysis based on achievement levels revealed that the class utilizing Google Docs had a relatively higher proportion of discourse from lower-achieving students. Additionally, differences were observed in the types of utterances and connection structures between the higher and lower-achieving students. The higher-achieving students took a leading role in providing suggestions and explanations, while the lower-achieving students played a role in transcribing them, with this tendency being more pronounced in the class using Google Docs. Lastly, students' changes in perception regarding the cause of static electricity were visualized using ENA. Based on the research findings, this study proposes strategies to enhance collaborative learning using Google Docs, including the use of open-ended problems to allow diverse opinions and outputs, and exploring the potential use of ENA to assess the learning effects of conceptual learning.

• 한국상하수도협회지
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• s.12
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• pp.138-145
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• 2005

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.223-228
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• 2002

Hypertension is characterized by multiple genetic and environmental factors. To establish the genetic basis of hypertension in Koreans, we investigated the genetic variations of two candidate genes (aldosterone synthase (CYP11B2), ${\gamma}$ subunit of the amiloride-sensitive epithelial sodium channel (ENaC) in the Korean patients with hypertension and normotensive controls. There were no significant differences in the genotype and allele frequencies between two groups, respectively. However, there was the significant difference between Korean and Caucasian populations in allele frequency of RFLPs in the two candidate genes. Therefore, these studies also need to be confirmed in other ethnic groups, although our results do not support a possible role of these genes on hypertension in Korean population

• Journal of Applied Reliability
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• v.13 no.1
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• pp.65-76
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• 2013

In order to assess the reliability of engine mount for a vehicles, life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows; i) the main failure mechanism is degradation failure of engine mount rubber by fatigue failure at dynamic load. ii) temperature is a second factor to affect a failure. iii) the life distribution of engine mount module is fitted well to Weibull life distribution and the shape parameter is 18.4 and the accelerated life model of that is fitted well to Arrhenius model.

• The Bulletin of The Korean Astronomical Society
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• v.31 no.2
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• pp.65.1-65.1
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• 2006

• Clinical and Experimental Pediatrics
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• v.51 no.8
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• pp.886-891
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• 2008

Mixed connective tissue disease (MCTD) is characterized by diverse symptoms including rheumatoid arthritis, scleroderma, systemic lupus erythematosus, and dermatomyositis, associated with high titers of antibodies to extractable nuclear antigen (ENA), especially anti-ribonucleoprotein (anti-RNP) antibody. Since the first report of 25 cases with MCTD in adults, there have been only a few cases of MCTD reported in children. Here, we report a rare childhood case of MCTD in a 7-year-old girl presenting initially with Raynaud's phenomenon, swollen hands, and ulceration of the right index finger tip followed by alopecia and arthritis during follow-up.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.117.1-117.1
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• 2012

Energetic neutral atoms (ENAs) are emitted by charge exchange collisions between energetic ions and cold neutral atoms. ENAs can be used as an alternative measure of the energetic ions in the source region because they maintain the energy and pitch angle of the source energetic ions. In the present study we present simulation results of the ENA emissions during a magnetic storm to be measured by the STEIN instrument onboard the CINEMA/TRIO satellites. The CINEMA/TRIO mission consists of three identical cubesats with low-altitude orbits. The STEIN instrument onboard each cubesat can measure ENAs with energies from ~4 keV to ~20 keV as well as suprathermal electrons and ions. The measurement of ENA emissions from ring current by STEIN is simulated using the models for energetic ring current ions and geocoronal neutral atoms. Especially we will discuss about the energy spectrum of the ENAs and the effect of transient variations of the ring current.

• Restorative Dentistry and Endodontics
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• v.43 no.4
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• pp.40.1-40.10
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• 2018

Objectives: This study evaluated the microtensile bond strength (${\mu}TBS$) of polymer-ceramic and indirect composite resin with 3 classes of resin cements. Materials and Methods: Two computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated polymer-ceramics (Enamic [ENA; Vita] and Lava Ultimate [LAV; 3M ESPE]) and a laboratory indirect composite resin (Gradia [GRA; GC Corp.]) were equally divided into 6 groups (n = 18) with 3 classes of resin cements: Variolink N (VAR; Vivadent), RelyX U200 (RXU; 3M ESPE), and Panavia F2 (PAN; Kuraray). The ${\mu}TBS$ values were compared between groups by 2-way analysis of variance and the post hoc Tamhane test (${\alpha}=0.05$). Results: Restorative materials and resin cements significantly influenced ${\mu}TBS$ (p < 0.05). In the GRA group, the highest ${\mu}TBS$ was found with RXU ($27.40{\pm}5.39N$) and the lowest with VAR ($13.54{\pm}6.04N$) (p < 0.05). Similar trends were observed in the ENA group. In the LAV group, the highest ${\mu}TBS$ was observed with VAR ($27.45{\pm}5.84N$) and the lowest with PAN ($10.67{\pm}4.37N$) (p < 0.05). PAN had comparable results to those of ENA and GRA, whereas the ${\mu}TBS$ values were significantly lower with LAV (p = 0.001). The highest bond strength of RXU was found with GRA ($27.40{\pm}5.39N$, p = 0.001). PAN showed the lowest ${\mu}TBS$ with LAV ($10.67{\pm}4.37N$; p < 0.001). Conclusions: When applied according to the manufacturers' recommendations, the ${\mu}TBS$ of polymer-ceramic CAD/CAM materials and indirect composites is influenced by the luting cements.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.57-64
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• 2013

Cells can resist and even recover from stress induced by acute hypoxia, whereas chronic hypoxia often leads to irreversible damage and eventually death. Although little is known about the response(s) to acute hypoxia in neuronal cells, alterations in ion channel activity could be preferential. This study aimed to elucidate which channel type is involved in the response to acute hypoxia in rat pheochromocytomal (PC12) cells as a neuronal cell model. Using perfusing solution saturated with 95% $N_2$ and 5% $CO_2$, induction of cell hypoxia was confirmed based on increased intracellular $Ca^{2+}$ with diminished oxygen content in the perfusate. During acute hypoxia, one channel type with a conductance of about 30 pS (2.5 pA at -80 mV) was activated within the first 2~3 min following onset of hypoxia and was long-lived for more than 300 ms with high open probability ($P_o$, up to 0.8). This channel was permeable to $Na^+$ ions, but not to $K^+$, $Ca^+$, and $Cl^-$ ions, and was sensitively blocked by amiloride (200 nM). These characteristics and behaviors were quite similar to those of epithelial sodium channel (ENaC). RT-PCR and Western blot analyses confirmed that ENaC channel was endogenously expressed in PC12 cells. Taken together, a 30-pS ENaC-like channel was activated in response to acute hypoxia in PC12 cells. This is the first evidence of an acute hypoxia-activated $Na^+$ channel that can contribute to depolarization of the cell.

• Bulletin of the Korean Space Science Society
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• 2006.10a
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• pp.32-32
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• 2006