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부하순환 하에서 제V급 복합레진 수복물의 미세변연누출에 대한 재접착제의 효과에 관한 연구
윤연희,김영재,김정욱,장기택,이상훈,김종철,한세현 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.3
저점도의 레진을 복합레진 수복물 위에 도포하는 것은 미세누출방지와 변연 완전성(integrity) 유지를 위한 한 방법이다. 하지만 장기간 관찰하면, 수복물은 저작압에 의한 영향을 받게 되는데, 저점도의 레진으로 수복물 변연부를 재접착(rebonding)하였을 때 저작압에 의한 응력에 견디면서 계속하여 수복물에 긍정적인 영향을 주는지에 대한 연구는 미흡한 실정이다. 본 연구는 부하순환(load cycling) 하에서 제Ⅴ급 수복물의 미세변연누출에 대한 재접착제 (rebonding agent)의 효과를 알아보고자 하였다. 40개의 건전한 소구치의 협면에 제Ⅴ급 와동을 형성하고 제조사의 지시대로 광중합복합레진으로 수복하였다. 20개씩 무작위로 나누어 표면전색을 하지 않는 Ⅰ군과 표면을 산부식 후 재접착한 Ⅱ군으로 설정하였다. 열순환 후 각 군에서 10개씩의 하위군 (A군=No load cycling군, B군=Load cycling군)으로 나누어 이중 B군의 시편에 1 Hz의 속도로 수직력이 4-100까지 100,000회의 부하순환을 가하였다. methylene blue용액에 침윤시켜 변연의 미세누출릉도를 평가하여 다음과 같은 결과를 얻었다. 1. 교합변연에서는 재접착과 무관하게 유의한 차이가 없었다(ⅠA-ⅡA군, ⅠB-ⅡB군) (p>0.05). 2. 치은변연의 경우는 부하순환을 하지 않은 군의 경우 재접착을 한 군(ⅡA군)이 재접착을 하지 않은 군 (ⅠA군)에 비해 더 적은 미세누출결과를 보였다(p<0.05). 3. 치은 변연에서 부하순환을 시행한 군의 경우에는 재접착을 한 군(ⅡB군)과 재접착을 하지 않은 군 (ⅠB군)과 유의차가 없는 비슷한 미세누출의 결과를 보였다(p>0.05). One clinical technique recommended f3r improving marginal integrity is "rebonding" or application of unfilled resins to the surface of composite restoration. But continuously the restorations are affected with occlusal load. There is room for doubt that the rebonding agent has the positive effect on microleakage in spite of the stress generated by the occlusal load. This study determined the effect of rebonding on microleakage of Class Ⅴ resin composite restorations under load cycling. Class Ⅴ cavities were prepared on the buccal surface of 40 sound extracted premolars and restored with a hybrid light-cured resin composite according to manufacturers' directions. They wert randomly divided into two groups consisting of 20 samples a control(group Ⅰ), without surface sealing, and the other group (group Ⅱ) in which margins were etched and rebonded. After thermocycling, each of groups was divided into subgroups (group A, B), and load cycling(total 100,000 cycles with 4-100N load at a rate of 1 Hz) were applied on the group B. Assessment of microleakage utilized methylene blue dye penetration. The following results were obtained : 1. In the occlusal region, no significant difference was noted in the scores regardless of whether or not the rebonding agent was used (group ⅠA-ⅡA, ⅠB-ⅡB) (p>0.05). 2. In the cervical region, the control group with rebonding (group ⅡA) showed the better result than the group without rebonding (group ⅠA) (p<0.05). 3. In the cervical region, the rebonded group with load cycling(group ⅡB) showed similar results to the groupf·ithout rebonding(group ⅠB) and no significant difference was noted(p>0.05).
강성준,박종연,황희용 강원대학교 산업기술연구소 2007 産業技術硏究 Vol.27 No.A
This paper presents a miniaturized electromagnetic wave detector. The dimension is reduced down to 31×18×13.5 ㎣ by using common OP-AMPs for amplification and oscillation. The strength from wave radiators is indicated by a color LED; green, orange and red colors mean the low, the middle and the high level, respectively. An alarm bell rings as the wave strength becomes above high level. The detector uses 3V battery. The detector could be used for a cellular phone decoration, a necklace pendant and a key holder.
수학 학습에 대한 정의적 성취 검사 도구 개발 및 검증
이종희 ( Chong Hee Lee ),김선희 ( Sun Hee Kim ),김수진 ( Soo Jin Kim ),김기연 ( Ki Yeon Kim ),김부미 ( Bu Mi Kim ),윤수철 ( Soo Cheol Yun ),김윤민 ( Yun Min Kim ) 한국수학교육학회 2011 수학교육 Vol.50 No.2
In this study, the researchers developed an inventory which can measure the affective achievement in mathematical learning especially targeted to Korean students. By using EFA and CFA, the six affective factors of mathematical learning such as learning directivity, self control, anxiety, interest, cognizing value and confidence are distinguished. Also, the content validity of this inventory was examined by the experts groups, composed of mathematics education professors, high school mathematics teachers, and measurement experts. The reliability of the instrument was high enough to trust the results. Through a large scaled sampling, the reliability and validity of this inventory were verified. In addition, this inventory was developed not by a partial aspects of a certain theory but based on the recent theories. Due to these reasons, the results of this study can be respected that it plays a leading part in understanding the affective achievement of Korean students.
Characterization of FK506 Biosynthetic Intermediates Involved in Post-PKS Elaboration
Ban, Yeon Hee,Shinde, Pramod B.,Hwang, Jae-yeon,Song, Myoung-Chong,Kim, Dong Hwan,Lim, Si-Kyu,Sohng, Jae Kyung,Yoon, Yeo Joon American Chemical Society and American Society of 2013 Journal of natural products Vol.76 No.6
<P>The post-PKS modification steps of FK506 biosynthesis include C9-oxidation and 31-<I>O</I>-methylation, but the sequence of these reactions and the exact route have remained unclear. This study details the post-PKS modification pathways in FK506 biosynthesis through the identification of all intermediates and in vitro enzymatic reactions of the cytochrome P450 hydroxylase FkbD and the methyltransferase FkbM. These results complete our understanding of post-PKS modification steps to FK506 showing the substrate flexibility of two enzymes involved and the existence of two parallel biosynthetic routes to FK506.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jnprdf/2013/jnprdf.2013.76.issue-6/np4001224/production/images/medium/np-2013-001224_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/np4001224'>ACS Electronic Supporting Info</A></P>
경증 외상관련 척추동맥박리의 임상양상 및 해부학적 위치 비교
정연희 ( Yeon Hee Chong ),안지윤 ( Ji Yun Ahn ),오범진 ( Bum Jin Oh ),김원 ( Won Kim ),임경수 ( Kyoung Soo Lim ) 대한외상학회 2007 大韓外傷學會誌 Vol.20 No.2
Purpose: This study aimed to find any difference in the clinical or the anatomical findings of vertebral artery dissection (VAD) between the trauma and the non-trauma groups. Methods: We retrospectively reviewed the clinical data and radiologic images of VAD patients. We compared data on symptoms, neurologic deficit, National institutes of health stroke scale (NIHSS) at admission, Rankin score (RS) at admission and discharge, and radiological findings including anatomical features, between the trauma and the non-trauma groups. Results: From January 1997 to May 2006, 42 patients were enrolled and 13 patients (31%) had a history of earlier trauma. Focal neurologic deficit (trauma group 11/13 vs. non-trauma group 11/29), cerebral stroke (10/13 vs. 9/29), and extradural lesions of dissection (6/13 vs. 3/28) were more common in the trauma group than non-trauma group (p=0.007, p=0.017, p=0.018, respectively) and NIHSS at admission and discharge were significantly higher (p=0.012, p=0.001, respectively). Dissecting aneurysms were less frequent in the trauma group (2/13 vs. 19/29, p=0.006). Subarachnoid hemorrhage and unfavorable prognostic value (Rankin score at discharge≥2) showed no differences between the groups (p=0.540, p=0.267, respectively). Conclusion: In VAD patients after trauma, focal neurologic deficit due to ischemic stroke and a steno-occlusive pattern are more frequent than they are in non-trauma patients. The location of dissection was most frequent at the extradural vertebral artery in the trauma group. NIHSS was higher in the trauma groups but the incidence of an unfavorable prognostic value (RS≥2) was not significantly different between the groups. (J Korean Soc Traumatol 2007;20:101-105)
Computation of mean size is based on perceived size.
Im, Hee Yeon,Chong, Sang Chul Psychonomic Society 2009 ATTENTION PERCEPTION & PSYCHOPHYSICS Vol.71 No.2
<P>The present study investigated whether computation of mean object size was based on perceived or physical size. The Ebbinghaus illusion was used to make the perceived size of a circle different from its physical size. Four Ebbinghaus configurations were presented either simultaneously (Experiment 1) or sequentially (Experiment 2) to each visual field, and participants were instructed to attend only to the central circles of each configuration. Participants' judgments of mean central circle size were influenced by the Ebbinghaus illusion. In addition, the Ebbinghaus illusion influenced the coding of individual size rather than the averaging. These results suggest that perceived rather than physical size was used in computing the mean size.</P>
Chemically fluorinated graphene oxide for room temperature ammonia detection at ppb levels
Kim, Yeon Hoo,Park, Ji Soo,Choi, You-Rim,Park, Seo Yun,Lee, Seon Yong,Sohn, Woonbae,Shim, Young-Seok,Lee, Jong-Heun,Park, Chong Rae,Choi, Yong Seok,Hong, Byung Hee,Lee, Jung Hun,Lee, Wi Hyong,Lee, Don The Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.36
<▼1><P>Detection of ppb level ammonia at room temperature is demonstrated using chemically fluorinated graphene oxide (CFGO). Fluorine adatom extremely enhances ammonia sensing capabilities through the changes of the charge distributions on adjacent functional groups, resulting in the variation in gas adsorption energies.</P></▼1><▼2><P>Chemoresistive gas sensors based on two-dimensional (2D) materials including graphene-based materials have attracted significant research interest owing to their potential use in next-generation technologies including the Internet of Things (IoT). The functionalization of 2D materials is considered as a key strategy to achieve superior gas sensing properties such as high selectivity, high sensitivity, and reversible response and recovery, because it can modulate the chemical and electrical properties of 2D materials for more efficient gas sensing. Herein, we present a facile solution process and the room temperature gas sensing properties of chemically fluorinated graphene oxide (CFGO). The CFGO sensors exhibit improved sensitivity, selectivity, and reversibility upon exposure to NH3 with a significantly low theoretical detection limit of ∼6 ppb at room temperature in comparison to NO2 sensing properties. The effect of fluorine doping on the sensing mechanism is examined by first-principles calculations based on density functional theory. The calculations reveal that the fluorine dopant changes the charge distribution on the oxygen containing functional groups in graphene oxide, resulting in the preferred selective adsorption and desorption of NH3 molecules. We believe that the remarkable NH3 sensing properties of CFGO and investigation by first-principles calculations would enlarge the possibility of functionalized 2D materials for practical gas sensing applications such as the IoT.</P></▼2>