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Medical Engineering & Physics

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https://www.readbyqxmd.com/read/30318362/detection-of-ischemic-changes-in-the-vascular-endothelial-cell-layer-by-using-microelectrochemical-impedance-spectroscopy
#1
Jung-Joon Cha, Jinhwan Kim, Joho Yun, Yangkyu Park, Jong-Hyun Lee
Endothelial cells have many important roles in the cardiovascular system, such as controlling vasomotor actions and hemostasis. In the event of endothelial cell dysfunction, the risk of cardiovascular disease increases. Therefore, the objective of this study was to investigate the early detection and diagnosis of endothelial cell dysfunction. Injury and restoration in vascular endothelial cells exposed to ischemic stress may affect changes in the electrical impedance. We measured the status of the endothelial cell layer by using microelectrochemical impedance spectroscopy...
October 11, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30314902/reduced-tibial-strain-shielding-with-extraosseous-total-knee-arthroplasty-revision-system
#2
Tomas A Correa, Bidyut Pal, Richard J van Arkel, Felice Vanacore, Andrew A Amis
BACKGROUND: Revision total knee arthroplasty (RTKA) has poorer results than primary total knee arthroplasty (TKA), and the prostheses are invasive and cause strain-shielding of the bones near the knee. This paper describes an RTKA system with extracortical fixation. It was hypothesised that this would reduce strain-shielding compared with intramedullary fixation. METHODS: Twelve replica tibiae were prepared for full-field optical surface strain analysis. They were either left intact, implanted with RTKA components with cemented intramedullary fixation stems, or implanted with a novel design with a tibial tray subframe supported by two extracortical fixation plates and screw fixation...
October 10, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30297165/patella-tracking-calculation-from-patellofemoral-positions-at-finite-angles-of-knee-flexion
#3
Jie Yao, Bin Yang, Yuxing Wang, Yubo Fan
Patellofemoral (PF) pain is a common knee disease. Patella tracking has a significant correlation with PF pain, therefore it could be used as an index for diagnosis and treatment evaluation. Previous research has proposed a method for measuring in vivo patella tracking by means of an interpolation algorithm. The present study aimed to quantify the effect of the interpolation parameters on the accuracy of the patella tracking with a motion capture experiment. The precise patella tracking of 5 knee specimens was collected and compared with the interpolated tracking...
October 5, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30293736/shoulder-loading-reliability-in-seated-able-bodied-subjects
#4
Richard Ballas, Nicolas Peyrot, Paul Allard, Teddy Caderby, Pascal Edouard, Georges Dalleau
Shoulder performance and sensorimotor control assessments help to identify shoulder instabilities and document the rehabilitation progress. Testing seated subjects in a position of hand prehension requires less controlled adjustments to maintain body balance in a clinically relevant situation. The objective of this work was to determine the test-retest repeatability of a novel shoulder stability test in seated subjects with the ipsi-lateral hand in prehension during four arm loading conditions. Able-bodied subjects were seated on a rigid chair fixed to a force plate...
October 4, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30282587/evaluation-of-the-accuracy-of-musculoskeletal-simulation-during-squats-by-means-of-instrumented-knee-prostheses
#5
Florian Schellenberg, William R Taylor, Adam Trepczynski, Renate List, Ines Kutzner, Pascal Schütz, Georg N Duda, Silvio Lorenzetti
Standard musculoskeletal simulation tools now offer widespread access to internal loading conditions for use in improving rehabilitation concepts or training programmes. However, despite broad reliance on their outcome, the accuracy of such loading estimations, specifically in deep knee flexion, remains generally unknown. The aim of this study was to evaluate the error of tibio-femoral joint contact force (JCF) calculations using musculoskeletal simulation compared to in vivo measured JCFs in subjects with instrumented total knee endoprostheses during squat exercises...
September 30, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30270005/study-of-impaired-cardiovascular-and-respiratory-coupling-during-orthostatic-stress-based-on-joint-symbolic-dynamics
#6
S Reulecke, S Charleston-Villalobos, J González-Hermosillo, R González-Camarena, A Voss, M Gaitán-González, G Hernández-Pacheco, R Schroeder, T Aljama-Corrales
The present study investigates the instantaneous coupling among the cardiac, vascular, and respiratory systems, using the heart rate, respiration, and systolic and diastolic blood pressure variability in 12 healthy and 16 vasovagal syncope female subjects during a head-up tilt (HUT) testing protocol at 70° This study contributes to the coupling analysis by using a nonlinear joint symbolic dynamics (JSD) in a high-temporal resolution scheme, based on 5 min segments of the time series that are shifted every minute...
September 27, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30262138/a-three-dimensional-visco-hyperelastic-fe-model-for-simulating-the-mechanical-dynamic-response-of-preloaded-phalanges
#7
Christophe Noël
This study lays the groundwork for a multi-scale strategy that will lead to a better understanding and prediction of the effects of vibration on the digital arterial network. This is accomplished by modelling the mechanical and biological factors that could disturb the basal vasoconstriction balance in the fingertip. The first stage of this novel approach involved building and validating an original dissipative constitutive law for the fingertip soft tissue for the purpose of finite element modelling of the mechanical response of preloaded phalanges in vibration...
September 24, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30243888/variability-in-strain-distribution-in-the-mice-tibia-loading-model-a-preliminary-study-using-digital-volume-correlation
#8
M Giorgi, E Dall'Ara
It is well known that bone has an enormous adaptive capacity to mechanical loadings, and to this extent, several in vivo studies on mouse tibia use established cyclic compressive loading protocols to investigate the effects of mechanical stimuli. In these experiments, the applied axial load is well controlled but the positioning of the hind-limb between the loading endcaps may dramatically affect the strain distribution induced on the tibia. In this study, the full field strain distribution induced by a typical in vivo setup on mouse tibiae was investigated through a combination of in situ compressive testing, µCT scanning and a global digital volume correlation (DVC) approach...
September 19, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30217436/corrigendum-to-a-theoretical-computerized-study-for-the-electrical-conductivity-of-arterial-pulsatile-blood-flow-by-an-elastic-tube-model-medical-engineering-physics-38-2016-1439-1448
#9
Hua Shen, Yong Zhu, Kai-Rong Qin
No abstract text is available yet for this article.
September 11, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30205937/rate-and-age-dependent-damage-elasticity-formulation-for-efficient-hip-fracture-simulations
#10
C C Villette, A T M Phillips
Prediction of bone failure is beneficial in a range of clinical situations from screening of osteoporotic patients with high fracture risk to assessment of protective equipment against trauma. Computational efficiency is an important feature to consider when developing failure models for iterative applications, such as patient-specific diagnosis or design of orthopaedic devices. The authors previously developed a methodology to generate efficient mesoscale structural full bone models. The aim of this study was to implement a damage elasticity formulation representative of an elasto-plastic material model with age and strain rate dependencies compatible with these structural models...
September 8, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30201284/cardiac-spiral-wave-drifting-due-to-spatial-temperature-gradients-a-numerical-study
#11
Guy Malki, Sharon Zlochiver
Cardiac rotors are believed to be a major driver source of persistent atrial fibrillation (AF), and their spatiotemporal characterization is essential for successful ablation procedures. However, electrograms guided ablation have not been proven to have benefit over empirical ablation thus far, and there is a strong need of improving the localization of cardiac arrhythmogenic targets for ablation. A new approach for characterize rotors is proposed that is based on induced spatial temperature gradients (STGs), and investigated by theoretical study using numerical simulations...
September 7, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30181023/sharif-human-movement-instrumentation-system-sharif-hmis-development-and-validation
#12
Mohammad Iman Mokhlespour Esfahani, Ali Akbari, Omid Zobeiri, Ehsan Rashedi, Mohamad Parnianpour
The interest in wearable systems among the biomedical engineering and clinical community continues to escalate as technical refinements enhance their potential use for both indoor and outdoor applications. For example, an important wearable technology known as a microelectromechanical system (MEMS) is demonstrating promising applications in the area of biomedical engineering. Accordingly, this study was designed to investigate the Sharif-Human Movement Instrumentation System (SHARIF-HMIS), consisting of inertial measurement units (IMUs), stretchable clothing, and a data logger-all of which can be used outside the controlled environment of a laboratory, thus enhancing its overall utility...
September 1, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30181022/3d-printed-composite-for-simulating-thermal-and-mechanical-responses-of-the-cortical-bone-in-orthopaedic-surgery
#13
Bruce L Tai, Yi-Tang Kao, Nolan Payne, Yihao Zheng, Lei Chen, Albert J Shih
Synthetic bones made of polyurethane (PU) foams or glass-fiber reinforced epoxy are often used in surgical training, planning, and tool analysis, but these materials cannot be 3D printed for a patient-specific design. This paper introduces a new type of bone-mimicking material made by the binder jetting technology and a post-strengthening process with epoxy, namely 3D polymer-infiltrated composite (3DPIC). 3DPIC has been previously evaluated by surgeons as a proper alternative to commercial synthetic bones, but no quantitative testing data is available...
September 1, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30177419/model-development-and-comparison-of-low-hemorrhage-risk-endoluminal-patch-thrombolytic-treatment-for-ischemic-stroke
#14
Zhen Qin, Francesco Ciucci, Chi Hang Chon, John C K Kwok, David C C Lam
Clot dissolution drugs delivered into the systemic circulation can dissolve intracranial blood clots in 90 min with 20-50% hemorrhage rate. Immobilizing <5% of the intravenous dosage on an endoluminal patch can reduce the dissolution time to <20 min with negligible hemorrhage risk. The thrombus dissolution behavior in endoluminal patch thrombolytic treatment is modeled and compared with experimental results from a companion study. Analyses showed that the thrombus dissolution time decreases with increasing dosage, but the dissolution time reaches a dosage-independent minimum when uPA dosage on the patch is >800 IU...
August 31, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30172653/motion-analysis-of-the-cervical-spine-during-extension-and-flexion-reliability-of-the-vertebral-marking-procedure
#15
Maciej Plocharski, Rene Lindstroem, Cassandra Frydendal Lindstroem, Lasse Riis Østergaard
Cervical spine motion analysis using videofluoroscopy is currently a technique without a gold standard. We demonstrate the reliability of a rigid and reliable analysis methodology for cervical motion using videofluoroscopic images, representing the entire range of motion during flexion and extension, from the neutral position to the end-range in the sagittal plane. Two researchers with radiography and vertebral marking expertise, and two inexperienced researchers with 10 hours of training manually marked anatomical structures on fluoroscopic images in a procedure designed to control for vertebral rotation around the mid-plane axis...
August 30, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30146392/an-intelligent-system-for-image-based-rating-of-corrosion-severity-at-stem-taper-of-retrieved-hip-replacement-implants
#16
Roohollah Milimonfared, Reza H Oskouei, Mark Taylor, Lucian B Solomon
Visual scoring of damage at taper junctions is the sole method to quantify corrosion in large-scale retrieval studies of failed hip replacement implants. This study introduces an intelligent image analysis-based method that objectively rates corrosion at stem taper of retrieved hip implants according to the well-known Goldberg scoring method. A Support Vector Machine classifier was used that takes in vectors of global and local textural features and assigns scores to the corresponding images. Bayesian optimisation fine-tunes the hyperparameters of the classifier to minimise the cross-validation error...
August 23, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30131279/experimentally-derived-viscoelastic-properties-of-human-skin-and-muscle-in-vitro
#17
Moon Jeong Kang, Bo-Seung Kim, Sejin Hwang, Hong Hee Yoo
Measurement of the mechanical properties of human skin in vivo is challenging. Moreover, those with regard to excitation frequency have been rarely reported thus far. In this study, a vibration-based experimental method was employed to measure the viscoelastic properties with regard to the excitation frequency. Pieces of human skin and skeletal muscle excised from cadavers immediately post mortem were stored in a sealed container. As the experiment began, they were removed from the container and used to measure the viscoelastic properties as time elapsed...
August 18, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30082204/wear-analysis-of-explanted-conventional-metal-back-polyethylene-glenoid-liners
#18
Gyorgy Kocsis, Charlie J Payne, Angus Wallace, Donal McNally
INTRODUCTION: Glenoid component wear and loosening is the Achilles heel of total shoulder replacement. Analysis of failed, revised implants might give an insight into the causes of component failure. Volumetric assessment of conventional total shoulder replacement glenoid liner wear rate and scanning electron microscopy was accomplished in this study for the purpose. Coherence scanning interferometry (white light scanner) 3D images were acquired. This method requires no physical contact, ionising radiation or extensive surface preparation...
August 3, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30131278/a-mixed-linear-modelling-characterisation-of-gender-and-speed-related-changes-in-spatiotemporal-and-kinematic-characteristics-of-gait-across-a-wide-speed-range-in-healthy-adults
#19
Ben Stansfield, Katrina Hawkins, Sarah Adams, Haseel Bhatt
In exploring the relationship between the kinematics of gait and speed of progression individual variation in patterns and gender differences have not always been adequately taken into account. In the current study mixed linear modelling was used to isolate changes with speed from those associated with individual variation and gender. Three-dimensional motion analysis of 20 participants (10M/10F, 25.7 ± 5.1 years) walking at a wide range of speeds (normalised speeds 0.10-0.55 ∼0.41-2.26 m/s) was recorded (775 walks)...
October 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/30122472/comparative-study-of-actuation-systems-for-portable-upper-limb-exoskeletons
#20
REVIEW
Soumya K Manna, Venketesh N Dubey
During the last two decades, a large variety of upper limb exoskeletons have been developed. Out of these, majority are platform based systems which might be the reason for not being widely adopted for post-stroke rehabilitation. Despite the potential benefits of platform-based exoskeletons as being rugged and reliable, stroke patients prefer to have a portable and user-friendly device that they can take home. However, the types of actuator as well as the actuation mechanism used in the exoskeleton are the inhibiting factors why portable exoskeletons are mostly non-existent for patient use...
October 2018: Medical Engineering & Physics
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