429 research outputs found
Current Research Findings on DevelopmentaI Disdorder
近年の特殊教育をめぐる状況の変化に伴い,通常学級に在籍しながら教育を受ける子どもへの特別な教育的対応が求められるようになってきた。しかし,学習障害,注意欠陥/多動性障害,高機能自閉症など軽度発達障害の実態は未だ十分には把握されていない。そこで,本稿ではこれらの障害の診断上の指標策定や特別支援法の確立に資する目的で,当該領域の最新の研究成果を概説した。その結果,個別支援計画作成の際に役立つと思われる研究成果が多く認められた。また, LDや自閉症では側性化の評価が, AD/HDではDoparnine transporterの測定などが診断上の手がかりとして注目され,臨床応用に向けた今後の研究が期待される
Influences of implant neck design and implant–abutment joint type on peri-implant bone stress and abutment micromovement: Three-dimensional finite element analysis
Objectives: Occlusal overloading is one of the causes of peri-implant bone resorption, and many studies on stress distribution in the peri-implant bone by three-dimensional finite element analysis (3D FEA) have been performed. However, the FEA models previously reported were simplified and far from representing what occurs in clinical situations. In this study, 3D FEA was conducted with simulation of the complex structure of dental implants, and the influences of neck design and connections with an abutment on peri-implant bone stress and abutment micromovement were investigated. Methods: Three types of two-piece implant CAD models were designed: external joint with a conical tapered neck (EJ), internal joint with a straight neck (IJ), and conical joint with a reverse conical neck (CJ). 3D FEA was performed with the setting of a “contact” condition at the component interface, and stress distribution in the peri-implant bone and abutment micromovement were analyzed. Results: The shear stress was concentrated on the mesiodistal side of the cortical bone for EJ. EJ had the largest amount of abutment micromovement. While the von Mises and shear stresses around the implant neck were concentrated on the labial bone for IJ, they were distributed on the mesiodistal side of the cortical bone for CJ. CJ had the least amount of abutment micromovement. Significance: Implants with a conical joint with an abutment and reverse conical neck design may effectively control occlusal overloading on the labial bone and abutment micromovement.Yamanishi Y., Yamaguchi S., Imazato S., et al. Influences of implant neck design and implant–abutment joint type on peri-implant bone stress and abutment micromovement: Three-dimensional finite element analysis. Dental Materials 28, 1126 (2012); https://doi.org/10.1016/j.dental.2012.07.160
Effects of the implant design on peri-implant bone stress and abutment micromovement: Three-dimensional finite element analysis of original computer-aided design models
Background: Occlusal overloading causes peri-implant bone resorption. Previous studies examined stress distribution in alveolar bone around commercial implants using three-dimensional (3D) finite element analysis. However, the commercial implants contained some different designs. The purpose of this study is to reveal the effect of the target design on peri-implant bone stress and abutment micromovement. Methods: Six 3D implant models were created for different implant-abutment joints: 1) internal joint model (IM); 2) external joint model (EM); 3) straight abutment (SA) shape; 4) tapered abutment (TA) shapes; 5) platform switching (PS) in the IM; and 6) modified TA neck design (reverse conical neck [RN]). A static load of 100 N was applied to the basal ridge surface of the abutment at a 45-degree oblique angle to the long axis of the implant. Both stress distribution in peri-implant bone and abutment micromovement in the SA and TA models were analyzed. Results: Compressive stress concentrated on labial cortical bone and tensile stress on the palatal side in the EM and on the labial side in the IM. There was no difference in maximum principal stress distribution for SA and TA models. Tensile stress concentration was not apparent on labial cortical bone in the PS model (versus IM). Maximum principal stress concentrated more on peri-implant bone in the RN than in the TA model. The TA model exhibited less abutment micromovement than the SA model. Conclusion: This study reveals the effects of the design of specific components on peri-implant bone stress and abutment displacement after implant-supported single restoration in the anterior maxilla.This is the pre-peer reviewed version of the following article:Yamanishi Y., Yamaguchi S., Imazato S., et al. Effects of the implant design on peri-implant bone stress and abutment micromovement: Three-dimensional finite element analysis of original computer-aided design models. Journal of Periodontology 85, (2014), which has been published in final form at https://doi.org/10.1902/jop.2014.140107. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving
Influence of implant length and diameter, bicortical anchorage, and sinus augmentation on bone stress distribution: Three-dimensional finite element analysis
Purpose: Clarification of the protocol for using short implants is required to enable widespread use of short implants as an available treatment option. The purpose of this study was to investigate the influences of implant length and diameter, bicortical anchorage, and sinus augmentation on peri-implant cortical bone stress by three-dimensional finite element analysis. Materials and Methods: For bone models with bone quantity A and C in the maxillary molar region, three-dimensional finite element analysis was performed using different lengths and diameters of implant computer-aided design models, and the degree of maximum principal stress distribution for each model was calculated. Results: For bone quantity A models, the degree of stress distribution of the 4-mm-diameter, 6-mm-length implant was the greatest. For bone quantity C models, the degree of stress distribution of the 5-mm-diameter, 6-mm-length implant with bicortical anchorage was much smaller than that for the 4-mm-diameter, 13-mm-length implant with sinus augmentation. Conclusion: The results of this study suggest that 6-mm-length implants should be selected in cases with bone quantity C where the bone width permits increasing implant diameter from 4 mm to 5 mm.Moriwaki H., Yamaguchi S., Nakano T., et al. Influence of implant length and diameter, bicortical anchorage, and sinus augmentation on bone stress distribution: Three-dimensional finite element analysis. International Journal of Oral and Maxillofacial Implants 31, 84 (2016); https://doi.org/10.11607/jomi.4217
Laterality on the Brain Function Measured by Transcranial Doppler Blood Flowmeter
発達障害の客観的評価法の確立を目指した研究の一環として,健常児・者における課題呈示による脳機能の左右差を経頭蓋的超音波ドプラー血流測定法(TCD) により評価するとともに,同法の有用性を検討することを目的として本研究を行った。対象は10歳から28歳の計9名の健常児・者で,エデインパラ利き手テストによる検討で全例右利きであった。TCDを用いてWISC-IIIの絵画完成カードによる課題呈示前後の血流速度と血管抵抗指数を測定し,比較検討を行った。その結果,中大脳動脈血流速度は9名中6名が右側で, 3名が左側でより大きな変化を認め,血管抵抗指数は, 9名中4名が右側で, 1名が左側でより大きな変化を認めた。エデインパラ利き手指数の結果と左中大脳動脈血流速度や血管抵抗指数の左右差との聞に一定の傾向は認められなかった。本研究で用いた課題では,両側の大脳半球機能が同時に活性化されたため,側性に関しての明瞭な結果が得られなかったものと考えられ,今後,より単純な課題の検討が妥当と思われた
Clarithromycin Suppresses Human Respiratory Syncytial Virus Infection-Induced Streptococcus pneumoniae Adhesion and Cytokine Production in a Pulmonary Epithelial Cell Line
Human respiratory syncytial virus (RSV) sometimes causes acute and severe lower respiratory tract illness in infants and young children. RSV strongly upregulates proinflammatory cytokines and the platelet-activating factor (PAF) receptor, which is a receptor for Streptococcus pneumoniae, in the pulmonary epithelial cell line A549. Clarithromycin (CAM), which is an antimicrobial agent and is also known as an immunomodulator, significantly suppressed RSV-induced production of interleukin-6, interleukin-8, and regulated on activation, normal T-cell expressed and secreted (RANTES). CAM also suppressed RSV-induced PAF receptor expression and adhesion of fluorescein-labeled S. pneumoniae cells to A549 cells. The RSV-induced S. pneumoniae adhesion was thought to be mediated by the host cell's PAF receptor. CAM, which exhibits antimicrobial and immunomodulatory activities, was found in this study to suppress the RSV-induced adhesion of respiratory disease-causing bacteria, S. pneumoniae, to host cells. Thus, CAM might suppress immunological disorders and prevent secondary bacterial infections during RSV infection
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