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화학과 생물 교과서에서 삼투 개념에 관한 설명 유형 분석
고영환,강대훈,박동조,김동욱,백성혜 한국과학교육학회 2002 한국과학교육학회지 Vol.22 No.4
이 연구에서는 고등학교와 대학교 화학과 생물 교과서에 제시된 삼투 개념에 대한 설명 유형 및 그림표현 유형을 분석하였다. 그리고 고등학교 화학Ⅱ 교과서와 생물Ⅱ교과서의 단원을 분석하였다. 분석 결과, 삼투현상에 대해서는 용매의 확산으로 설명하는 유형, 충돌로 설명하는 유형, 수화로 설명하는 유형, 농도의 평형으로 설명하는 유형 그리고 구멍을 막는 것으로 설명하는 유형 등 다섯 가지 유형으로 설명하고 있었다. 그리고 삼투 개념에 대한 설명 유형과 교과서에 제시된 그림 표현 유형 사이에 일치하지 않는 경우도 분석되었다. In this study, we analyzed types of explanation on osmosis concept that were represented in chemistry and biology textbooks of high school and college. There were 5 types of explanation on osmosis concept. The types of explanation were diffusion of solvent, collision, hydration, equilibrium of concentration and screen of holes. Last two types of explanation were classified into misconceptions. The various types of explanation on osmosis concept might cause to have be a reason that students had many misconceptions and to feel difficult to learn about osmosis concept. Many of textbooks is accord to types of concept explanation and figure explanation on osmosis but some is not
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고근호,조영곤,진철희,유상훈,김종욱,박병철,기영재,최희영,김종진 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3
This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface, V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15s and rewet with Aqua-Prep F for 20s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p〈0.05). but there was no statistically significant difference between group BD and DR (p)0.05). At the enamel-resin interface, group D showed the gap of 2 ㎛ thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.
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Ko, Young-Uk,Yun, Ho-Jin,Jeong, Kwang-Seok,Kim, Yu-Mi,Yang, Seung-Dong,Kim, Seong-Hyeon,Kim, Jin-Sup,An, Jin-Un,Eom, Ki-Yun,Lee, Hi-Deok,Lee, Ga-Won The Institute of Electronics and Information Engin 2015 Journal of semiconductor technology and science Vol.15 No.1
In this study, an n-ZnO/p-Si heterojunction diode with embedded Ag nanoparticles was fabricated to investigate the possible improvement of light trapping via the surface plasmon resonance effect for solar cell applications. The Ag nanoparticles were fabricated by the physical sputtering method. The acquired current-voltage curves and optical absorption spectra demonstrated that the application of Ag nanoparticles in the n-ZnO/p-Si interface increased the photo current, particularly in specific wavelength regions. The results indicate that the enhancement of the photo current was caused by the surface plasmon resonance effect generated by the Ag nanoparticles. In addition, minority carrier lifetime measurements showed that the recombination losses caused by the Ag nanoparticles were negligible. These results suggest that the embedding of Ag nanoparticles is a powerful method to improve the performance of n-ZnO/p-Si heterojunction solar cells.
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Ko Joo Young,Shin Dae Youp,Kim Tae Uk,Kim Seo Young,Hyun Jung Keun,Lee Seong Jae 대한재활의학회 2021 Annals of Rehabilitation Medicine Vol.45 No.2
Objective To identify the variables of videofluoroscopic swallowing study (VFSS) that are useful for predicting the risk of aspiration pneumonia in elderly patients with dysphagia. Methods A total of 251 patients (aged 65 years or more) were included and divided into a pneumonia group (n=133) and a non-pneumonia group (n=118). The pneumonia group included patients who had been diagnosed with aspiration pneumonia, and individuals in the non-pneumonia group did not have pneumonia but were referred for VFSS. The medical records and results of VFSS were reviewed and compared between the groups retrospectively. Results The pneumonia group exhibited a male preponderance and a higher 8-point Penetration-Aspiration Scale (8PPAS) score. The mean values of 8PPAS score for swallowing thick liquid and rice porridge was significantly higher in the pneumonia group. The pharyngeal delay time (PDT) and pharyngeal transit time (PTT) were significantly longer in the pneumonia group. The amounts of vallecular and pyriform sinus residue were increased in the pneumonia group. The delay in swallowing reflex and the decrease in laryngeal elevation were more frequently observed in the pneumonia group. Among those variables, PDT and PTT were identified as significant predictors of aspiration pneumonia based on logistic regression analysis. Conclusion The present study delineated the findings of VFSS, suggesting an increased risk of aspiration pneumonia in elderly patients with dysphagia. The results demonstrate that prolonged PDT and PTT are significant predictors of aspiration pneumonia.
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Young-Uk Ko,Ho-Jin Yun,Kwang-Seok Jeong,Yu-Mi Kim,Seung-Dong Yang,Seong-Hyeon Kim,Jin-Sup Kim,Jin-Un An,Ki-Yun Eom,Hi-Deok Lee,Ga-Won Lee 대한전자공학회 2015 Journal of semiconductor technology and science Vol.15 No.1
In this study, an n-ZnO/p-Si heterojunction diode with embedded Ag nanoparticles was fabricated to investigate the possible improvement of light trapping via the surface plasmon resonance effect for solar cell applications. The Ag nanoparticles were fabricated by the physical sputtering method. The acquired current-voltage curves and optical absorption spectra demonstrated that the application of Ag nanoparticles in the n-ZnO/p-Si interface increased the photo current, particularly in specific wavelength regions. The results indicate that the enhancement of the photo current was caused by the surface plasmon resonance effect generated by the Ag nanoparticles. In addition, minority carrier lifetime measurements showed that the recombination losses caused by the Ag nanoparticles were negligible. These results suggest that the embedding of Ag nanoparticles is a powerful method to improve the performance of n-ZnO/p-Si heterojunction solar cells.
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Ko, Young-Uk,Yun, Ho-Jin,Jeong, Kwang-Seok,Kim, Yu-Mi,Yang, Seung-Dong,Kim, Seong-Hyeon,Kim, Jin-Sup,An, Jin-Un,Lee, Hi-Deok,Lee, Ga-Won Elsevier 2016 THIN SOLID FILMS - Vol.598 No.-
<P><B>Abstract</B></P> <P>Low-frequency noise (1/<I>f</I> noise) has been analyzed to characterize the amorphous/crystalline silicon heterojunction diodes with passivation layer of a-Si:H (p–i–n), Al<SUB>2</SUB>O<SUB>3</SUB> (p–Al<SUB>2</SUB>O<SUB>3</SUB>–n), and ZnO (p–ZnO–n) and without passivation (p–n). Four types of diodes show high ideality factors and the dependence of the reverse leakage current on the electric field shows that the diodes commonly follow the Poole–Frenkel model, which is field-assisted thermionic emission from the traps in the materials. However, the conduction mechanism in the reverse bias can be more easily clarified from the bias dependence of the 1/<I>f</I> noise. That is, the p–i–n and p–n diodes are affected by the diffusion current mechanism, and the p–Al<SUB>2</SUB>O<SUB>3</SUB>–n and p–ZnO–n diodes with an inferior interface are affected by the generation–recombination current mechanism. This indicates that the p–i–n and p–n diodes have a better interface quality than the p–Al<SUB>2</SUB>O<SUB>3</SUB>–n and the p–ZnO–n. These results show that the 1/<I>f</I> noise measurement can be a useful and more sensitive method to estimate the interface quality of heterojunction diodes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Leakage current is on Poole–Frenkel in heterojunction diode with inferior interface. </LI> <LI> Low-frequency noise is proposed to evaluate heterojunction diode. </LI> <LI> Low-frequency noise is useful to distinguish the leakage conduction mechanism. </LI> </UL> </P>
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Protein kinase A-induced phosphorylation at the Thr154 affects stability of DJ-1
Ko, Yeon Uk,Kim, Su-Jeong,Lee, Juhyung,Song, Min-Young,Park, Kang-Sik,Park, Jun Bae,Cho, Hyun-Soo,Oh, Young J. Elsevier 2019 Parkinsonism & related disorders Vol.66 No.-
<P><B>Abstract</B></P> <P><B>Introduction</B></P> <P>Most cases of Parkinson's disease (PD) are sporadic, but genetic variations have been discovered in PD patients. PARK7/DJ-1 is a known cause of early-onset autosomal-recessive PD and is implicated in neuroprotection against oxidative stress. Although several post-translational modifications of DJ-1 have been proposed, phospho-modification of DJ-1 and its functional consequences have been less studied.</P> <P><B>Methods</B></P> <P>Putative phosphorylation sites of DJ-1 were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS analysis). Subsequently, phosphorylation site of DJ-1 was confirmed by <I>in vitro</I> kinase assay and cell-based pull-down assay. Impaired dimer formation of phospho-null mutant was measured using DSS crosslinking assay and immunoprecipitation assay. To evaluate physiological consequences of this event, protein stability of DJ-1 WT and DJ-1 phospho-null mutant were compared using cycloheximide chase assay and ubiquitination assay.</P> <P><B>Results</B></P> <P>Here, we showed that DJ-1 directly bound to the catalytic subunit of protein kinase A (PKAcα). We found that PKAcα is responsible for phosphorylation of DJ-1 at the T154 residue. Interestingly, dimerization of DJ-1 was not detected in a DJ-1 T154A mutant. Furthermore, stability of the DJ-1 T154A mutant was dramatically reduced compared with that of wild-type DJ-1. We found that DJ-1 T154A was prone to degradation by the ubiquitin proteasome system (UPS).</P> <P><B>Conclusion</B></P> <P>We identified a novel phosphorylation site of DJ-1. Furthermore, we determined protein kinase A that is responsible for this posttranslational modification. Finally, we demonstrated physiological consequences of this event focusing on dimerization and protein stability of DJ-1.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PKAcα phosphorylates PARK7/DJ1 at the Thr154 residue. </LI> <LI> Disruption of Thr154 phosphorylation is linked to a lower stability. </LI> </UL> </P>
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Ko, Young-Seon,Kwon, Young-Uk American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.9
<P>Mesoporous zirconia thin films (MZFs) were synthesized using zirconium hydroxide sol particles and a structure directing agent, Pluronic F127 (PEO<SUB>106</SUB>PPO<SUB>70</SUB>PEO<SUB>106</SUB>, EO = ethylene oxide, PO = propylene oxide). By controlling the F127/Zr ratio, we obtained two distinct MZFs with one in the <I>Fmmm</I> structure and the other in the <I>P</I>6<SUB>3</SUB>/<I>mmc</I> structure. The pore structures of these films were characterized by low-angle X-ray diffraction, grazing incidence small-angle X-ray scattering, electron microscopy, and N<SUB>2</SUB> sorption measurement. The <I>Fmmm</I> structure has interconnected pores and the <I>P</I>6<SUB>3</SUB>/<I>mmc</I> structure has less accessible pores. The MZFs were functionalized with glucose oxidase (GOx) and were studied for their potentials as an electrochemical sensor for glucose. The GOx-functionalized MZF electrodes show high sensitivity to glucose in a broad range of glucose concentration of 0.025 – 6.8 mM, which can be attributed to their biocompatibility providing a favorable microenvironment for GOx immobilization and to their 3D pore structures with good accessibility of pores.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-9/am303248p/production/images/medium/am-2012-03248p_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am303248p'>ACS Electronic Supporting Info</A></P>
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