Comparison of the cyclic fatigue resistance of One Curve, F6 Skytaper, Protaper Next, and Hyflex CM endodontic files

Gouédard Charlotte,Pino Laurent,Arbab-Chirani Reza,Arbab-Chirani Shabnam,Chevalier Valérie 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.2

Objectives This study compared the cyclic fatigue resistance of One Curve (C wire) and F6 Skytaper (conventional austenite nickel-titanium [NiTi]), and 2 instruments with thermo-mechanically treated NiTi: Protaper Next X2 (M wire) and Hyflex CM (CM wire). Materials and Methods Ten new instruments of each group (size: 0.25 mm, 6% taper in the 3 mm tip region) were tested using a rotary bending machine with a 60° curvature angle and a 5 mm curvature radius, at room temperature. The number of cycles until fracture was recorded. The length of the fractured instruments was measured. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). The data were analyzed using one-way analysis of variance and the post hoc Tukey test. The significance level was set at 0.05. Results At 60°, One Curve, F6 Skytaper and Hyflex CM had significantly longer fatigue lives than Protaper Next X2 (p < 0.05). No statistically significant differences were found in the cyclic fatigue lives of One Curve, F6 Skytaper, and Hyflex CM (p > 0.05). SEM images of the fracture surfaces of the different instruments showed typical features of fatigue failure. Conclusions Within the conditions of this study, at 60° and with a 5 mm curvature radius, the cyclic fatigue life of One Curve was not significantly different from those of F6 Skytaper and Hyflex CM. The cyclic fatigue lives of these 3 instruments were statistically significantly longer than that of Protaper Next. Objectives This study compared the cyclic fatigue resistance of One Curve (C wire) and F6 Skytaper (conventional austenite nickel-titanium [NiTi]), and 2 instruments with thermo-mechanically treated NiTi: Protaper Next X2 (M wire) and Hyflex CM (CM wire). Materials and Methods Ten new instruments of each group (size: 0.25 mm, 6% taper in the 3 mm tip region) were tested using a rotary bending machine with a 60° curvature angle and a 5 mm curvature radius, at room temperature. The number of cycles until fracture was recorded. The length of the fractured instruments was measured. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). The data were analyzed using one-way analysis of variance and the post hoc Tukey test. The significance level was set at 0.05. Results At 60°, One Curve, F6 Skytaper and Hyflex CM had significantly longer fatigue lives than Protaper Next X2 (p < 0.05). No statistically significant differences were found in the cyclic fatigue lives of One Curve, F6 Skytaper, and Hyflex CM (p > 0.05). SEM images of the fracture surfaces of the different instruments showed typical features of fatigue failure. Conclusions Within the conditions of this study, at 60° and with a 5 mm curvature radius, the cyclic fatigue life of One Curve was not significantly different from those of F6 Skytaper and Hyflex CM. The cyclic fatigue lives of these 3 instruments were statistically significantly longer than that of Protaper Next.

Advances in the understanding of molybdenum effect on iodine and caesium reactivity in condensed phase in the primary circuit in nuclear severe accident conditions

Gouëllo Mélany,Hokkinen Jouni,Kärkelä Teemu 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.8

In the case of a severe accident in a Light Water Reactor, the issue of late release of fission products, from the primary circuit surfaces is of particular concern due to the direct impact on the source term. CsI is the main iodine compound present in the primary circuit and can be deposited as particles or condensed species. Its chemistry can be affected by the presence of molybdenum, and can lead to the formation of gaseous iodine. The present work studied chemical reactions on the surfaces involving gaseous iodine release. CsI and MoO3 were used to highlight the effects of carrier gas composition and oxygen partial pressure on the reactions. The results revealed a noticeable effect of the presence of molybdenum on the formation of gaseous iodine, mainly identified as molecular iodine. In addition, the oxygen

政治社會化와 그 內容

李球載 서울 敎育大學校 1977 論文集 Vol.10 No.-

웹기반 구조중심 협동학습 시스템의 설계 및 구현

정규옥,양형정,최숙영 한국컴퓨터교육학회 2004 컴퓨터교육학회 논문지 Vol.7 No.3

협동학습 모델 중에서 매우 간단하고 적용이 쉬운 구조중심 협동학습은 다양한 구조의 유기적 연결과 학습내용의 결합을 통해 교수학습이 이루어진다. 본 연구에서는 이러한 구조중심의 협동학습을 위한 교수-학습 모델을 제안하고, 이를 지원하는 웹기반 구조중심 협동학습 시스템을 설계 및 구현하였다. 본 연구에서 제안하는 구조중심 협동학습 모델에서는 교과학습에 적용할 수 있는 구체적인 틀을 제시하여 협동학습을 효과적으로 지원할 수 있도록 하였다. 또한 학습 내용과 형태에 따라 다른 구조를 적용할 수 있도록 지식 습득형, 탐구형, 기능 숙달형 구조로 분류하고 이에 따른 적용 모형들을 제시하고 있다. 이러한 모형들을 기반으로 실제 협동학습을 수행할 수 있도록 시스템을 구현하여, 수업에 적용한 후 그 효과를 분석해 보았다. One of the cooperative learning models, the cooperative learning of structural approach which is very simple and easily applicable accomplishes teaching-learning through combining learning contents and organic connections of various structures. This work proposes a cooperative teaching-learning model for the structural approach, designs and implements a web-based cooperative system supporting it. The model provides a concrete frame which can apply to a subject learning thus could effectively support cooperative learning. Furthermore, it classifies learning into three types such as knowledge learning, investigation, and function mastering and presents a structure application model for each so as to apply different structures according to learning materials and types. We implemented a system that performs cooperative learning on the basis of these models, applied to a class, and analyzed the effect of it.

國家觀 確立을 위한 敎育에서 考慮되어야 할 몇 가지 問題點

球 載 서울 敎育大學校 1976 論文集 Vol.9 No.-

Use of Denaturing High-Performance Liquid Chromatography (DHPLC) to Characterize the Bacterial and Fungal Airway Microbiota of Cystic Fibrosis Patients

Jérôme Mounier,Geneviève Héry-Arnaud,Audrey Gouëllo,Marlène Keravec,Solène Le Gal,Grégory Pacini,Stella Debaets,Gilles Nevez,Gilles Rault,Georges Barbier 한국미생물학회 2014 The journal of microbiology Vol.52 No.4

The aim of this study was to evaluate the use of denaturinghigh-performance liquid chromatography (DHPLC) to characterizecystic fibrosis (CF) airway microbiota includingboth bacteria and fungi. DHPLC conditions were first optimizedusing a mixture of V6, V7 and V8 region 16S rRNAgene PCR amplicons from 18 bacterial species commonlyfound in CF patients. Then, the microbial diversity of 4 sputumsamples from 4 CF patients was analyzed using culturalmethods, cloning/sequencing (for bacteria only) and DHPLCpeak fraction collection/sequencing. DHPLC analysis allowedidentifying more bacterial and fungal species than the classicalculture methods, including well-recognized pathogenssuch as Pseudomonas aeruginosa. Even if a lower number ofbacterial Operational Taxonomic Units (OTUs) was identifiedby DHPLC, it allowed to find OTUs unidentified bycloning/sequencing. The combination of both techniquespermitted to correlate the majority of DHPLC peaks to definedOTUs. Finally, although Aspergillus fumigatus detectionusing DHPLC can still be improved, this techniqueclearly allowed to identify a higher number of fungal speciesversus classical culture-based methods. To conclude, DHPLCprovided meaningful additional data concerning pathogenicbacteria and fungi as well as fastidious microorganisms presentwithin the CF respiratory tract. DHPLC can be consideredas a complementary technique to culture-dependentanalyses in routine microbiological laboratories.

Contradictory Relationships between Cancer and Normal Cells and Implications for Anti-cancer Therapy

Gou, Xing-Chun,Kong, Derek,Tang, Xu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.13

Cancer treatment remains a serious problem worldwide. Analysis of the relationship between cancer cells and normal cells reveals that these two share characteristics in contradiction, thus could be analyzed by using contradictory principles. Under the theory of contradictory principles, induction of a dormant state or reversal of cancer cells is an important treatment strategy beyond traditional cytotoxic therapy. Normal cells are also the targets and under the influence of anti-cancer treatments and should be considered during therapy. Findings based on crosstalk between these two cell types may offer opportunities for the development of new biomarkers and therapies.

Efficient Median Filter Using Irregular Shape Window

Gou Chol Pok 한국정보전자통신기술학회 2018 한국정보전자통신기술학회논문지 Vol.11 No.5

Median filtering is a nonlinear method which is known to be effective in removing impulse noise while preserving local image structure relatively well. However, it could still suffer the smearing phenomena of edges and fine details into neighbors due to undesirable influence from the pixels whose values are far off from the true value of the pixel at hand. This drawback mainly comes from the fact that median filters typically employ a regular shape window for collecting the pixels used in the filtering operation. In this paper, we propose a median filtering method which employs an irregular shape filter window in collecting neighboring pixels around the pixel to be denoised. By employing an irregular shape window, we can achieve good noise suppression while preserving image details. Experimental results have shown that our approach is superior to regular window-based methods.

Symposium 3 Molecular Bio-imaging : Bio-imaging for vascular and Lymphatic vessels

( Gou Young Koh ),( Endothelial Cell Research Group ) 생화학분자생물학회 2005 62회 KSBMB Annual Meeting in 2005 Vol.- No.-

THE METHOD OF LOWER AND UPPER SOLUTIONS FOR IMPULSIVE FRACTIONAL EVOLUTION EQUATIONS IN BANACH SPACES

Gou, Haide,Li, Yongxiang Korean Mathematical Society 2020 대한수학회지 Vol.57 No.1

In this paper, we investigate the existence of mild solutions for a class of fractional impulsive evolution equation with periodic boundary condition by means of the method of upper and lower solutions and monotone iterative method. Using the theory of Kuratowski measure of noncompactness, a series of results about mild solutions are obtained. Finally, two examples are given to illustrate our results.