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Sermsak Sumanont, Supachoke Nopamassiri, Artit Boonrod, Punyawat Apiwatanakul, Arunnit Boonrod, Chanakarn Phornphutkul
BACKGROUND: Suspension suture button fixation was frequently used to treat acromioclavicular joint (ACJ) dislocation. However, there were many studies reporting about complications and residual horizontal instability after fixation. Our study compared the stability of ACJ after fixation between coracoclavicular (CC) fixation alone and CC fixation combined with ACJ repair by using finite element analysis (FEA). MATERIALS AND METHODS: A finite element model was created by using CT images from the normal shoulder...
March 20, 2018: European Journal of Orthopaedic Surgery & Traumatology: Orthopédie Traumatologie
Stoyan Popkirov, Vera Flasbeck, Uwe Schlegel, Georg Juckel, Martin Brüne
Frontal EEG asymmetry (FEA) has been studied as both state and trait parameter in emotion regulation and affective disorders. Its significance in borderline personality disorder (BPD) remains largely unknown. Twenty-six BPD patients and 26 healthy controls underwent EEG before and after mood induction using aversive images. A slight but significant shift from left- to right-sided asymmetry over prefrontal electrodes occurred across all subjects. In BPD baseline FEA over F7 and F8 correlated significantly with childhood trauma and functional neurological "conversion" symptoms as assessed by respective questionnaires...
March 15, 2018: Journal of Trauma & Dissociation
Sung-Yong Cho, Yun-Hyuk Huh, Chan-Jin Park, Lee-Ra Cho
PURPOSE: To investigate the stress distribution in an implant-abutment complex with a preloaded abutment screw by comparing implant-abutment engagement features using three-dimensional finite element analysis (FEA). MATERIALS AND METHODS: For FEA modeling, two implants-one with a single (S) engagement system and the other with a double (D) engagement system-were placed in the human mandibular molar region. Two types of abutments (hexagonal, conical) were connected to the implants...
March 2018: International Journal of Oral & Maxillofacial Implants
Hamed A Hamed, Hamdy A Marzook, Nahed E Ghoneem, Mohamed I El-Anwar
AIM: This study aimed to evaluate the effect of different implant angulations in posterior maxilla on stress distribution by finite element analysis and verify its results experimentally. METHODS: Two simplified models were prepared for an implant placed vertically and tilted 25° piercing the maxillary sinus. Geometric models' components were prepared by Autodesk Inventor then assembled in ANSYS for finite element analysis. The results of finite element analysis were verified against experimental trials results which were statistically analysed using student t-test (level of significance p < 0...
February 15, 2018: Open Access Macedonian Journal of Medical Sciences
Marcel Heers, Moritz Helias, Tanguy Hedrich, Matthias Dümpelmann, Andreas Schulze-Bonhage, Tonio Ball
The foremost aim of presurgical epilepsy evaluation is the delineation of the seizure onset zone (SOZ). There is increasing evidence that fast epileptic activity (FEA, 14-250 Hz) occurring interictally, i.e. between seizures, is predominantly localized within the SOZ. Currently it is unknown, which frequency band of FEA performs best in identifying the SOZ, although prior studies suggest highest concordance of spectral changes with the SOZ for high frequency changes. We suspected that FEA reflects dampened oscillations in local cortical excitatory-inhibitory neural networks, and that interictal FEA in the SOZ is a consequence of reduced oscillatory damping...
2018: NeuroImage: Clinical
Shuman Yang, Yunhua Luo, Lang Yang, Enrico Dall'Ara, Richard Eastell, Andrew L Goertzen, Eugene V McCloskey, William D Leslie, Lisa M Lix
BACKGROUND: Dual-energy X-ray absorptiometry (DXA)-based finite element analysis (FEA) has been studied for assessment of hip fracture risk. Femoral strength (FS) is the maximum force that the femur can sustain before its weakest region reaches the yielding limit. Fracture risk index (FRI), which also considers subject-specific impact force, is defined as the ratio of von Mises stress induced by a sideways fall to the bone yield stress over the proximal femur. We compared risk stratification for prior hip fracture using FS and FRI derived from DXA-based FEA...
March 8, 2018: Bone
Linchu Han, Chengzhi Liu, Cunbo Fan, Zhenwei Li, Jingxu Zhang, Xiaolin Yin
A warping harness is proposed to simply and efficiently correct low-order aberrations that occur during manufacturing and operation of a telescope. For the Thirty Meter Telescope (TMT) tertiary mirror, the issue to be solved by the warping harness is particularly challenging due to its complicated load conditions and limited mounting space. In this study, first, a new type of whiffletree-based warping harness configuration applied to a ¼-prototype TMT tertiary mirror is presented and optimized using finite element analysis (FEA) to improve the output precision of the moment actuator...
March 1, 2018: Applied Optics
Hakan Arinc
PURPOSE: To evaluate the effects of prosthetic material on the degree of stress to the cortical bone, trabecular bone, framework, and implants using finite element analysis (FEA). MATERIALS AND METHODS: A mandibular implant-supported fixed prosthesis was designed. Different prosthetic materials [cobalt-chromium-supported ceramic, zirconia-supported ceramic, and zirconia-reinforced polymethyl methacrylate (ZRPMMA)-supported resin] were used. FEA was used to evaluate stress under different loading conditions...
March 5, 2018: Implant Dentistry
Yuanhan Chang, Abhijit Anil Tambe, Yoshinobu Maeda, Masahiro Wada, Tomoya Gonda
A literature review of finite element analysis (FEA) studies of dental implants with their model validation process was performed to establish the criteria for evaluating validation methods with respect to their similarity to biological behavior. An electronic literature search of PubMed was conducted up to January 2017 using the Medical Subject Headings "dental implants" and "finite element analysis." After accessing the full texts, the context of each article was searched using the words "valid" and "validation" and articles in which these words appeared were read to determine whether they met the inclusion criteria for the review...
March 8, 2018: International Journal of Implant Dentistry
Adeel Anwar, Zhen Zhang, Decheng Lv, Gang Lv, Zhi Zhao, Yanfeng Wang, Yue Cai, Wasim Qasim, Muhammad Umar Nazir, Ming Lu
BACKGROUND: Clinically there are different fixation methods used for fixation of the posterior malleolar fractures (PMF), but the best treatment modality is still not clear. Few studies have concentrated on this issue, least of all using a biomechanical comparison. The purpose of this study was to carry out a computational comparative biomechanics of three different commonly used fixation constructs for the fixation of PMF by finite element analysis (FEA). METHODS: Computed tomography (CT) images were used to reconstruct three dimensional (3D) model of the tibia...
March 6, 2018: BMC Musculoskeletal Disorders
Dorota Konietzko-Meier, Kamil Gruntmejer, Jordi Marcé-Nogué, Adam Bodzioch, Josep Fortuny
Finite Element Analysis (FEA) is a useful method for understanding form and function. However, modelling of fossil taxa invariably involves assumptions as a result of preservation-induced loss of information in the fossil record. To test the validity of predictions from FEA, given such assumptions, these results could be compared to independent lines of evidence for cranial mechanics. In the present study a new concept of using bone microstructure to predict stress distribution in the skull during feeding is put forward and a correlation between bone microstructure and results of computational biomechanics (FEA) is carried out...
2018: PeerJ
Huamin Zhao, Cunfu He, Lyu Yan, Haijun Zhang
It is necessary to develop a transducer that can quickly detect the inner and outer wall defects of thick-walled pipes, in order to ensure the safety of such pipes. In this paper, a flexible broadband Rayleigh-waves comb transducer based on PZT (lead zirconate titanate) for defect detection of thick-walled pipes is studied. The multiple resonant coupling theory is used to expand the transducer broadband and the FEA (Finite Element Analysis) method is used to optimize transducer array element parameters. Optimization results show that the best array element parameters of the transducer are when the transducer array element length is 30 mm, the thickness is 1...
March 2, 2018: Sensors
Shun Huang, Yanjiang Han, Min Chen, Kongzhen Hu, Yongshuai Qi, Penghui Sun, Men Wang, Hubing Wu, Guiping Li, Quanshi Wang, Zhiyun Du, Kun Zhang, Suqing Zhao, Xi Zheng
Epidermal growth factor receptor (EGFR) has gained significant attention as a therapeutic target. Several EGFR targeting drugs (Gefitinib and Erlotinib) have been approved by US Food and Drug Administration (FDA) and have received high approval in clinical treatment. Nevertheless, the curative effect of these medicines varied in many solid tumors because of the different levels of expression and mutations of EGFR. Therefore, several PET radiotracers have been developed for the selective treatment of responsive patients who undergo PET/CT imaging for tyrosine kinase inhibitor (TKI) therapy...
September 1, 2017: Bioorganic & Medicinal Chemistry Letters
Wen-Wei Shen, Yu-Min Lin, Sheng-Tsai Wu, Chia-Hsin Lee, Shin-Yi Huang, Hsiang-Hung Chang, Tao-Chih Chang, Kuan-Neng Chen
In this study, through silicon via (TSV)-less interconnection using the fan-out wafer-level-packaging (FO-WLP) technology and a novel redistribution layer (RDL)-first wafer level packaging are investigated. Since warpage of molded wafer is a critical issue and needs to be optimized for process integration, the evaluation of the warpage issue on a 12-inch wafer using finite element analysis (FEA) at various parameters is presented. Related parameters include geometric dimension (such as chip size, chip number, chip thickness, and mold thickness), materials' selection and structure optimization...
August 1, 2018: Journal of Nanoscience and Nanotechnology
M E T Silva, M P L Parente, S Brandão, T Mascarenhas, R M Natal Jorge
The mechanical characteristics of the female pelvic floor are relevant to understand pelvic floor dysfunctions (PFD), and how they are related with changes in their biomechanical behavior. Urinary incontinence (UI) and pelvic organ prolapse (POP) are the most common pathologies, which can be associated with changes in the mechanical properties of the supportive structures in the female pelvic cavity. PFD have been studied through different methods, from experimental tensile tests using tissues from fresh female cadavers or tissues collected at the time of a transvaginal hysterectomy procedure, or by applying imaging techniques...
February 8, 2018: Journal of Biomechanics
Adam D Sylvester, Patricia A Kramer
Finite element analysis (FEA) is a powerful tool for evaluating questions of functional morphology, but the application of FEA to extant or extinct creatures is a non-trivial task. Three categories of input data are needed to appropriately implement FEA: geometry, material properties, and boundary conditions. Geometric data are relatively easily obtained from imaging techniques, but often material properties and boundary conditions must be estimated. Here we conduct sensitivity analyses of the effect of the choice of Young's Modulus for elements representing trabecular bone and muscle loading complexity on the proximal femur using a finite element mesh of a modern human femur...
February 16, 2018: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
L Jay Katz, Carl Erb, Amadeu Carceller Guillamet, Antonio M Fea, Lilit Voskanyan, Jane Ellen Giamporcaro, Dana M Hornbeak
Purpose: Evaluate long-term outcomes after one, two, or three trabecular micro-bypass stents implanted in a standalone procedure in eyes with open-angle glaucoma taking ocular hypotensive medication. Patients and methods: Prospective randomized ongoing study of 119 subjects (109 with 42-month follow-up) with open-angle glaucoma, preoperative intraocular pressure (IOP) 18-30 mmHg on one to three glaucoma medications, and unmedicated (post-washout) IOP 22-38 mmHg...
2018: Clinical Ophthalmology
Paulo Eduardo Herbst, Eduardo Bortolas de Carvalho, Rafael C Salatti, Laiz Valgas, Rodrigo Tiossi
PURPOSE: To study the force used for tightening tapered one-piece prosthetic abutments and their influence on the removal torque value and stress level of the prosthetic abutment after cyclic loading. MATERIALS AND METHODS: Fourteen implants and prosthetic abutments were divided into two groups (n = 7): G1, 20 Ncm; and G2, 32 Ncm (manufacturer recommended). A 20-mm T-shaped horizontal bar was adapted to the abutments. A 12-Hz cyclic loading was applied to the specimens in an electrodynamic testing system with the maximum number of cycles set to 106...
February 8, 2018: International Journal of Oral & Maxillofacial Implants
Murat Kuscu, Ozgur B Akan
We consider a microfluidic molecular communication (MC) system, where the concentration-encoded molecular messages are transported via fluid flow-induced convection and diffusion, and detected by a surface-based MC receiver with ligand receptors placed at the bottom of the microfluidic channel. The overall system is a convection-diffusion-reaction system that can only be solved by numerical methods, e.g., finite element analysis (FEA). However, analytical models are key for the information and communication technology (ICT), as they enable an optimisation framework to develop advanced communication techniques, such as optimum detection methods and reliable transmission schemes...
2018: PloS One
Leslie R Lamb, Manisha Bahl, Kevin S Hughes, Constance D Lehman
BACKGROUND: Our aim was to compare the pathologic upgrade rates of high-risk breast lesions (HRLs) on digital two-dimensional mammography (DM) vs digital breast tomosynthesis (DBT). STUDY DESIGN: The study cohort was composed of patients with HRLs diagnosed by image-guided core needle biopsy from December 2007 to February 2011 (DM group, before DBT integration) and from January 2013 to March 2016 (DBT group, after complete DBT integration). Medical records were reviewed for surgical outcomes and follow-up imaging...
February 2, 2018: Journal of the American College of Surgeons
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