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Pesquisa : G01.374.618 [Categoria DeCS]
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  1 / 3310 MEDLINE  
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PMID:28552927
Autor:Marvan J; Horak Z; Vilimek M; Horny L; Kachlik D; Baca V
Endereço:Department of Orthopedics and Traumatology, Third Faculty of Medicine, Charles University, Ruska 87, 10000 Prague, Czech Republic.
Título:Fixation of distal fibular fractures: A biomechanical study of plate fixation techniques.
Fonte:Acta Bioeng Biomech; 19(1):33-39, 2017.
ISSN:1509-409X
País de publicação:Poland
Idioma:eng
Resumo:Ankle fractures are complex injuries with variable prognoses that depend upon many factors. The aim of the treatment is to restore the ankle joint biomechanical stability with maximum range of motion. Most ankle fractures are fibular fractures, which have a typical oblique fracture line in the distal fibula located in the area of the tibiofibular syndesmosis. The aim of this study was to simulate numerically several fixation techniques of the distal fibular fractures, evaluate their stability, determine their impact on surrounding tissue load, and correlate the results to clinical treatment experience. The following three models of fibular fracture fixation were used: (a) plate fixation with three screws attached above/below and lag screws, (b) plate fixation with two screws attached above/below and lag screws, and (c) three lag screws only. All three fracture fixation models were analyzed according to their use in both healthy physiological bone and osteoporotic bone tissue. Based on the results of Finite Element Analysis for these simulations, we found that the most appropriate fixation method for Weber-B1 fibular fractures was an unlocked plate fixation using six screws and lag screws, both in patients with physiological and osteoporotic bone tissue. Conversely, the least appropriate fixation method was an unlocked plate fixation with four screws and lag screws. Although this fixation method reduces the stress on patients during surgery, it greatly increased loading on the bone and, thus, the risk of fixation failure. The final fixation model with three lag screws only was found to be appropriate only for very limited indications.
Tipo de publicação: JOURNAL ARTICLE


  2 / 3310 MEDLINE  
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PMID:28552924
Autor:Lughmani WA; Farukh F; Bouazza-Marouf K; Ali H
Endereço:Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Leicestershire, UK.
Título:Drilling resistance: A method to investigate bone quality.
Fonte:Acta Bioeng Biomech; 19(1):55-62, 2017.
ISSN:1509-409X
País de publicação:Poland
Idioma:eng
Resumo:PURPOSE: Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill-bit penetration and drill-bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. METHODS: This study demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the quality of the bone. To understand the variability and anisotropic behaviour of cortical bone tissue, specimens cut from three anatomic positions of pig and bovine were investigated at the same drilling speed and feed rate. RESULTS: The experimental results showed that the drilling force does not only vary from one animal bone to another, but also vary within the same bone due to its changing microstructure. Drilling force does not give a direct indication of bone quality; therefore it has been correlated with screw pull-out force to provide a realistic estimation of the bone quality. A significantly high value of correlation (r2 = 0.93 for pig bones and r2 = 0.88 for bovine bones) between maximum drilling force and normalised screw pull-out strength was found. CONCLUSIONS: The results show that drilling data can be used to indicate bone quality during orthopaedic surgery.
Tipo de publicação: JOURNAL ARTICLE


  3 / 3310 MEDLINE  
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PMID:28552921
Autor:Xiao X; Hao W; Li X; Wan B; Shan G
Endereço:School of Rehabilitation Medicine, Binzhou Medical University, Yantai, Shandong, China.
Título:The influence of landing mat composition on ankle injury risk during a gymnastic landing: a biomechanical quantification.
Fonte:Acta Bioeng Biomech; 19(1):105-113, 2017.
ISSN:1509-409X
País de publicação:Poland
Idioma:eng
Resumo:PURPOSE: About 70% injury of gymnasts happened during landing - an interaction between gymnast and landing mat. The most injured joint is the ankle. The current study examined the effect of mechanical properties of landing mat on ankle loading with aims to identify means of decreasing the risk of ankle injury. METHOD: Gymnastic skill - salto backward stretched with 3/2 twist was captured by two high-speed camcorders and digitized by using SIMI-Motion software. A subject-specific, 14-segment rigid-body model and a mechanical landing-mat model were built using BRG.LifeMODTM. The landings were simulated with varied landing-mat mechanical properties (i.e., stiffness, dampness and friction coefficients). RESULT: Real landing performance could be accurately reproduced by the model. The simulations revealed that the ankle angle was relatively sensitive to stiffness and dampness of the landing mat, the ankle loading rate increased 26% when the stiffness was increased by 30%, and the changing of dampness had notable effect on horizontal ground reaction force and foot velocity. Further, the peak joint-reaction force and joint torque were more sensitive to friction than to stiffness and dampness of landing mat. Finally, ankle muscles would dissipate about twice energy (189%) when the friction was increased by 30%. CONCLUSION: Loads to ankles during landing would increase as the stiffness and dampness of the landing mat increase. Yet, increasing friction would cause a substantial rise of the ankle internal loads. As such, the friction should be a key factor influencing the risk of injury. Unfortunately, this key factor has rarely attracted attention in practice.
Tipo de publicação: JOURNAL ARTICLE


  4 / 3310 MEDLINE  
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PMID:28648660
Autor:Simunovic M; Manneville JB; Renard HF; Evergren E; Raghunathan K; Bhatia D; Kenworthy AK; Voth GA; Prost J; McMahon HT; Johannes L; Bassereau P; Callan-Jones A
Endereço:Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France; Sorbonne Universités, UPMC University Paris 06, 75005 Paris, France; Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, The University of Chicago, 5735 S. El
Título:Friction Mediates Scission of Tubular Membranes Scaffolded by BAR Proteins.
Fonte:Cell; 170(1):172-184.e11, 2017 Jun 29.
ISSN:1097-4172
País de publicação:United States
Idioma:eng
Resumo:Membrane scission is essential for intracellular trafficking. While BAR domain proteins such as endophilin have been reported in dynamin-independent scission of tubular membrane necks, the cutting mechanism has yet to be deciphered. Here, we combine a theoretical model, in vitro, and in vivo experiments revealing how protein scaffolds may cut tubular membranes. We demonstrate that the protein scaffold bound to the underlying tube creates a frictional barrier for lipid diffusion; tube elongation thus builds local membrane tension until the membrane undergoes scission through lysis. We call this mechanism friction-driven scission (FDS). In cells, motors pull tubes, particularly during endocytosis. Through reconstitution, we show that motors not only can pull out and extend protein-scaffolded tubes but also can cut them by FDS. FDS is generic, operating even in the absence of amphipathic helices in the BAR domain, and could in principle apply to any high-friction protein and membrane assembly.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Membrane Proteins); 0 (centaurin beta2, human); EC 2.3.- (Acyltransferases); EC 2.3.1.52 (2-acylglycerophosphate acyltransferase)


  5 / 3310 MEDLINE  
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PMID:28411741
Autor:Arena SL; Garman CR; Nussbaum MA; Madigan ML
Endereço:High Point University, High Point, NC, USA. Electronic address: sarena@highpoint.edu.
Título:Required friction during overground walking is lower among obese compared to non-obese older men, but does not differ with obesity among women.
Fonte:Appl Ergon; 62:77-82, 2017 Jul.
ISSN:1872-9126
País de publicação:England
Idioma:eng
Resumo:Obesity and aging have been independently associated with altered required friction during walking, but it is unclear how these factors interact to influence the likelihood of slipping. Therefore, the purpose of this study was to determine whether there are differences related to obesity and aging on required friction during overground walking. Fourteen older non-obese, 11 older obese, 20 younger non-obese, and 20 younger obese adults completed walking trials at both a self-selected and hurried speed. When walking at a hurried speed, older obese men walked at a slower gait speed and exhibited lower frictional demands compared both to older non-obese men and to younger obese men. No differences in required friction were found between non-obese and obese younger adults. These results suggest that the increased rate of falls among obese or older adults is not likely due to a higher risk of slip initiation.
Tipo de publicação: JOURNAL ARTICLE


  6 / 3310 MEDLINE  
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PMID:28743045
Autor:Prata AA; Santos JM; Timchenko V; Reis NC; Stuetz RM
Endereço:UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
Título:Wind friction parametrisation used in emission models for wastewater treatment plants: A critical review.
Fonte:Water Res; 124:49-66, 2017 Nov 01.
ISSN:1879-2448
País de publicação:England
Idioma:eng
Resumo:Emission models are widely applied tools for estimating atmospheric emissions from wastewater treatment plants (WWTPs). The friction velocity u is a key variable for the modelling of emissions from passive liquid surfaces in WWTPs. This work evaluated different parametrisations of u for passive liquid surfaces at the scale of WWTP units, which present relatively small fetches, based on available wind friction and wave data measured at wind-wave tanks (fetches spanning from approximately 3 to 100 m, and wind speeds from 2 to 17 m s ). The empirical correlation by Smith (1980; J. Phys. Oceanogr. 10, 709-726), which has been frequently adopted in air emission models (despite the fact that it was originally derived for the ocean) presented a general tendency to overestimate u , with significant (although not extreme) relative errors (mean and maximum errors of 13.5% and 36.6%, respectively); the use of Charnock's relation, with Charnock constant 0.010, performed in a very similar manner (mean and maximum errors of 13.3% and 37.8%, respectively). Better estimates of u were achieved by parametrisations based on the significant wave steepness. Simplified correlations between the wind drag and the non-dimensional fetch were obtained. An approach was devised, comprising the use of Charnock's relation (with Charnock constant 0.010) and of these simplified correlations, depending on the ranges of frequency of the peak waves, fetch and wind speed. The proposed approach predicted u with improved accuracy (mean, maximum and 95%-percentile relative errors of 6.6%, 16.7% and 13.9%, respectively), besides being able to incorporate the influence of the fetch in the wind drag, thus taking into account the size of the tanks in the WWTPs.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Air Pollutants); 0 (Waste Water)


  7 / 3310 MEDLINE  
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PMID:28886084
Autor:Groves D; Fisher J; Williams S
Endereço:Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom.
Título:An in vitro simulation method for the tribological assessment of complete natural hip joints.
Fonte:PLoS One; 12(9):e0184226, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:The use of hip joint simulators to evaluate the tribological performance of total hip replacements is widely reported in the literature, however, in vitro simulation studies investigating the tribology of the natural hip joint are limited with heterogeneous methodologies reported. An in vitro simulation system for the complete natural hip joint, enabling the acetabulum and femoral head to be positioned with different orientations whilst maintaining the correct joint centre of rotation, was successfully developed for this study. The efficacy of the simulation system was assessed by testing complete, matched natural porcine hip joints and porcine hip hemiarthroplasty joints in a pendulum friction simulator. The results showed evidence of biphasic lubrication, with a non-linear increase in friction being observed in both groups. Lower overall mean friction factor values in the complete natural joint group that increased at a lower rate over time, suggest that the exudation of fluid and transition to solid phase lubrication occurred more slowly in the complete natural hip joint compared to the hip hemiarthroplasty joint. It is envisaged that this methodology will be used to investigate morphological risk factors for developing hip osteoarthritis, as well as the effectiveness of early interventional treatments for degenerative hip disease.
Tipo de publicação: JOURNAL ARTICLE


  8 / 3310 MEDLINE  
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PMID:27753530
Autor:Chen L; Di C; Chen X; Li Z; Luo J
Endereço:a School of Mechanical Engineering , Nanjing University of Science and Technology , Nanjing , China.
Título:Friction properties of biological functional materials: PVDF membranes.
Fonte:Bioengineered; 8(1):78-84, 2017 Jan 02.
ISSN:2165-5987
País de publicação:United States
Idioma:eng
Resumo:Touch is produced by sensations that include approaching, sliding, pressing, and temperature. This concept has become a target of research in biotechnology, especially in the field of bionic biology. This study measured sliding and pressing with traditional tactile sensors in order to improve a machine operator's judgment of surface roughness. Based on the theory of acoustic emission, this study combined polyvinylidene fluoride (PVDF) with a sonic transducer to produce tactile sensors that can detect surface roughness. Friction between PVDF films and experimental materials generated tiny acoustic signals that were transferred into electrical signals through a sonic transducer. The characteristics of the acoustic signals for the various materials were then analyzed. The results suggest that this device can effectively distinguish among different objects based on roughness. Tactile sensors designed using this principle and structure function very similarly to the human body in recognizing the surface of an object.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Biocompatible Materials); 0 (Membranes, Artificial); 0 (Polyvinyls); 24937-79-9 (polyvinylidene fluoride)


  9 / 3310 MEDLINE  
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PMID:28346437
Autor:Smutny M; Ákos Z; Grigolon S; Shamipour S; Ruprecht V; Capek D; Behrndt M; Papusheva E; Tada M; Hof B; Vicsek T; Salbreux G; Heisenberg CP
Endereço:Institute of Science and Technology Austria, Am Campus 1, A-3400 Klosterneuburg, Austria.
Título:Friction forces position the neural anlage.
Fonte:Nat Cell Biol; 19(4):306-317, 2017 Apr.
ISSN:1476-4679
País de publicação:England
Idioma:eng
Resumo:During embryonic development, mechanical forces are essential for cellular rearrangements driving tissue morphogenesis. Here, we show that in the early zebrafish embryo, friction forces are generated at the interface between anterior axial mesoderm (prechordal plate, ppl) progenitors migrating towards the animal pole and neurectoderm progenitors moving in the opposite direction towards the vegetal pole of the embryo. These friction forces lead to global rearrangement of cells within the neurectoderm and determine the position of the neural anlage. Using a combination of experiments and simulations, we show that this process depends on hydrodynamic coupling between neurectoderm and ppl as a result of E-cadherin-mediated adhesion between those tissues. Our data thus establish the emergence of friction forces at the interface between moving tissues as a critical force-generating process shaping the embryo.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Cadherins); 0 (Zebrafish Proteins)


  10 / 3310 MEDLINE  
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PMID:28573762
Autor:Mizuta M; Kurita T; Dillon NP; Kimball EE; Garrett CG; Sivasankar MP; Webster RJ; Rousseau B
Endereço:Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Título:In vivo measurement of vocal fold surface resistance.
Fonte:Laryngoscope; 127(10):E364-E370, 2017 Oct.
ISSN:1531-4995
País de publicação:United States
Idioma:eng
Resumo:OBJECTIVES/HYPOTHESIS: A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model. STUDY DESIGN: Prospective animal study. METHODS: New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy. RESULTS: In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia. CONCLUSIONS: These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology. LEVEL OF EVIDENCE: NA Laryngoscope, 127:E364-E370, 2017.
Tipo de publicação: JOURNAL ARTICLE



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