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Annals of Biomedical Engineering

Mostafa Abbasi, Mohammed S Barakat, Danny Dvir, Ali N Azadani
Computational modeling and simulation has become more common in design and development of bioprosthetic heart valves. To have a reliable computational model, considering accurate mechanical properties of biological soft tissue is one of the most important steps. The goal of this study was to present a non-invasive material characterization framework to determine mechanical propertied of soft tissue employed in bioprosthetic heart valves. Using integrated experimental methods (i.e., digital image correlation measurements and hemodynamic testing in a pulse duplicator system) and numerical methods (i...
September 18, 2018: Annals of Biomedical Engineering
Navein Arumugasaamy, Javier Navarro, J Kent Leach, Peter C W Kim, John P Fisher
Epithelial barriers are the body's natural defense system to regulating passage from one domain to another. In our efforts to understand what can and cannot cross these barriers, models have emerged as a reductionist approach to rigorously study and investigate this question. In particular, in vitro tissue models have become prominent as there is an increased exploration of understanding biological molecular transport. Herein, we introduce the pertinent physiology, then discuss recent studies and approaches for building models of five epithelial tissues: skin, the gastrointestinal tract, the lungs, the blood-brain barrier, and the placenta...
September 14, 2018: Annals of Biomedical Engineering
Lia Prevedello, Federica Michielin, Manuel Balcon, Enrico Savio, Piero Pavan, Nicola Elvassore
Mechanical stress has been proven to be an important factor interfering with many biological functions through mechano-sensitive elements within the cells. Despite the current interest in mechano-transduction, the development of suitable experimental tools is still characterized by the strife to design a compact device that allows high-magnification real-time imaging of the stretched cells, thus enabling to follow the dynamics of cellular response to mechanical stimulations. Here we present a microfluidic multi-layered chip that allows mechanical deformation of adherent cells maintaining a fixed focal plane, while allowing independent control of the soluble microenvironment...
September 14, 2018: Annals of Biomedical Engineering
Peng-Na Wei, Rongfu Xie, Rongnian Tang, Chuang Li, Janis Kim, Ming Wu
The goal of this study was to examine the optimal strategies for the recognition of gait phase based on surface electromyogram (sEMG) of leg muscles while children with cerebral palsy (CP) walked on a treadmill. Ten children with CP were recruited to participate in this study. sEMG from eight leg muscles and leg position signals were recorded while subjects walked on a treadmill. The position signals of left and right legs were used to develop a five gait sub-phases classifier, i.e., mid stance, terminal stance, pre-swing, mid swing, and terminal swing...
September 14, 2018: Annals of Biomedical Engineering
Hoda Hatoum, Lakshmi P Dasi
Blood damage and platelet activation are inherent problems with present day bi-leaflet mechanical heart valve designs. Passive flow control through different arrangements of vortex generators (VG) as means of improving pressure gradients and reducing turbulence are investigated. Rectangular VG arrays were mounted on the downstream surfaces of a 23 mm 3D printed mechanical valve. The effect of VGs on the resulting flow structures were assessed under pulsatile physiological flow conditions where high resolution particle image velocimetry measurement was performed...
September 12, 2018: Annals of Biomedical Engineering
Daniel S Elson, Kevin Cleary, Pierre Dupont, Robert Merrifield, Cameron Riviere
No abstract text is available yet for this article.
September 12, 2018: Annals of Biomedical Engineering
Oren M Rotman, Brandon Kovarovic, Wei-Che Chiu, Matteo Bianchi, Gil Marom, Marvin J Slepian, Danny Bluestein
Transcatheter aortic valve replacement (TAVR) is a minimally-invasive approach for treating severe aortic stenosis. All clinically-used TAVR valves to date utilize chemically-fixed xenograft as the leaflet material. Inherent limitation of the tissue (e.g., calcific degeneration) motivates the search for alternative leaflet material. Here we introduce a novel polymeric TAVR valve that was designed to address the limitations of tissue-valves. In this study, we experimentally evaluated the hemodynamic performance of the valve and compared its performance to clinically-used valves: a gold standard surgical tissue valve, and a TAVR valve...
September 7, 2018: Annals of Biomedical Engineering
Amir H Khalighi, Bruno V Rego, Andrew Drach, Robert C Gorman, Joseph H Gorman, Michael S Sacks
Ischemic mitral regurgitation (IMR) is a currently prevalent disease in the US that is projected to become increasingly common as the aging population grows. In recent years, image-based simulations of mitral valve (MV) function have improved significantly, providing new tools to refine IMR treatment. However, clinical implementation of MV simulations has long been hindered as the in vivo MV chordae tendineae (MVCT) geometry cannot be captured with sufficient fidelity for computational modeling. In the current study, we addressed this challenge by developing a method to produce functionally equivalent MVCT models that can be built from the image-based MV leaflet geometry alone...
September 5, 2018: Annals of Biomedical Engineering
Joanna F Weber, Loraine L Y Chiu, Stefan Balko, Stephen D Waldman
Dynamic mechanical stimulation has been an effective method to improve the growth of tissue engineering cartilage constructs derived from immature cells. However, when more mature cell populations are used, results are often variable due to the differing responses of these cells to external stimuli. This can be especially detrimental in the case of mechanical loading. In previous studies, multi-modal mechanical stimulation in the form of stochastic resonance was shown to be effective at improving the growth of young bovine chondrocytes...
September 5, 2018: Annals of Biomedical Engineering
Giulio Ruffini, David Ibañez, Eleni Kroupi, Jean-François Gagnon, Jacques Montplaisir, Ronald B Postuma, Marta Castellano, Aureli Soria-Frisch
Idiopathic rapid eye movement sleep behavior disorder (RBD) is a serious risk factor for neurodegenerative processes such as Parkinson's disease (PD). We investigate the use of EEG algorithmic complexity derived metrics for its prognosis. We analyzed resting state EEG data collected from 114 idiopathic RBD patients and 83 healthy controls in a longitudinal study forming a cohort in which several RBD patients developed PD or dementia with Lewy bodies. Multichannel data from ~ 3 min recordings was converted to spectrograms and their algorithmic complexity estimated using Lempel-Ziv-Welch compression...
August 30, 2018: Annals of Biomedical Engineering
Hoda Hatoum, Jennifer Dollery, Scott M Lilly, Juan A Crestanello, Lakshmi Prasad Dasi
Leaflet thrombosis is a complication associated with transcatheter aortic valve (TAV) replacement (TAVR) correlated with sinus flow stasis. Sinus hemodynamics are important because they dictate shear stress and washout necessary to avoid stasis on TAV leaflets. Sinus flow is controlled by TAV axial deployment position but little is known regarding TAV axis misalignment effect. This study aims to elucidate TAV angular misalignment with respect to aortic root axis effect on sinus flow stasis potentially leading to leaflet thrombosis...
August 27, 2018: Annals of Biomedical Engineering
Martin J C van Gemert, Cornelis M A Bruijninckx, Ton G van Leeuwen, H A Martino Neumann, Pieter J J Sauer
Commercial software package "Growth Analyser Viewer Edition" ("GAVE") aims to document, monitor and analyze growth and development in children and adolescents. Although its clinical and scientific use is widespread, there are no published studies that describe the method and its validation. We were informed that GAVE calculates the weight velocity (kg/year) at age t from the weight difference between t and 448 days earlier or at birth, divided by the time difference. We recently discussed a case of false child abuse diagnosis (Pediatric Condition Falsification), resulting in the separation of the child from its parents, in which GAVE played a negative contributing role...
August 27, 2018: Annals of Biomedical Engineering
Jean-Paul Richalet, Dominique Marchant, Jose-Luis Macarlupu, Nicolas Voituron
The measurement of plasma volume (Vp ) in humans and animals is frequently performed by the Evans blue dye dilution method. However, after injection of Evans blue into the circulation, no steady state is observed because of delayed mixing and progressive leakage of dye out of vascular space. Various methods of calculation have been proposed, either with a single blood sampling 5-10 min after dye injection (Single point method), or with extrapolation at time zero of a logarithmic decay (Log linear method). We propose a method based on a two-compartment hypothesis taking into account the initial mixing and the leakage phase in the time course of dye concentration...
August 22, 2018: Annals of Biomedical Engineering
Alyssa Huntington, Emanuele Rizzuto, Steven Abramowitch, Zaccaria Del Prete, Raffaella De Vita
Pelvic organ prolapse, the descent of the pelvic organs from their normal anatomical position, is a common condition among women that is associated with mechanical alterations of the vaginal wall. In order to characterize the complex mechanical behavior of the vagina, we performed planar biaxial tests of vaginal specimens in both the passive (relaxed) and active (contracted) states. Specimens were isolated from virgin, female Long-Evans rats (n = 16) and simultaneously stretched along the longitudinal direction (LD) and circumferential direction (CD) of the vagina...
August 22, 2018: Annals of Biomedical Engineering
Ricardo Morán-Navarro, Javier Courel-Ibáñez, Alejandro Martínez-Cava, Elena Conesa-Ros, Alejandro Sánchez-Pay, Ricardo Mora-Rodriguez, Jesús G Pallarés
This experiment investigates the validity of six thermometers with different measuring sensors, operation and site of application, to estimate core temperature (Tc ) in comparison to an ingestible thermometric sensor based on quartz crystal technology. Measurements were obtained before, during and after exercise in the heat, controlling the presence of air-cooling and skin sweating. Twelve well-trained men swallowed the ingestible thermometer 6 h before the trial. After pre-exercise resting measurements at 20 °C, subjects entered a heat chamber held at 40 °C...
August 22, 2018: Annals of Biomedical Engineering
Katariina A H Myller, Juuso T J Honkanen, Jukka S Jurvelin, Simo Saarakkala, Juha Töyräs, Sami P Väänänen
Segmentation of contrast-enhanced computed tomography (CECT) images enables quantitative evaluation of morphology of articular cartilage as well as the significance of the lesions. Unfortunately, automatic segmentation methods for CECT images are currently lacking. Here, we introduce a semiautomated technique to segment articular cartilage from in vivo CECT images of human knee. The segmented cartilage geometries of nine knee joints, imaged using a clinical CT-scanner with an intra-articular contrast agent, were compared with manual segmentations from CT and magnetic resonance (MR) images...
August 21, 2018: Annals of Biomedical Engineering
Shalin A Parikh, Raymond Gomez, Mirunalini Thirugnanasambandam, Sathyajeeth S Chauhan, Victor De Oliveira, Satish C Muluk, Mark K Eskandari, Ender A Finol
Abdominal aortic aneurysm (AAA) is an asymptomatic aortic disease with a survival rate of 20% after rupture. It is a vascular degenerative condition different from occlusive arterial diseases. The size of the aneurysm is the most important determining factor in its clinical management. However, other measures of the AAA geometry that are currently not used clinically may also influence its rupture risk. With this in mind, the objectives of this work are to develop an algorithm to calculate the AAA wall thickness and abdominal aortic diameter at planes orthogonal to the vessel centerline, and to quantify the effect of geometric indices derived from this algorithm on the overall classification accuracy of AAA based on whether they were electively or emergently repaired...
August 21, 2018: Annals of Biomedical Engineering
Song Zhang, Rajesh Rajamani, A Serdar Sezen
Fluid accumulation in the lower extremities is an early indicator of disease deterioration in cardiac failure, chronic venous insufficiency and lymphedema. At-home wearable monitoring and early detection of fluid accumulation can potentially lead to prompt medical intervention and avoidance of hospitalization. Current methods of fluid accumulation monitoring either suffer from lack of specificity and sensitivity or are invasive and cost-prohibitive to use on a daily basis. Ultrasound velocity in animal and human tissue has been found to change with water content...
August 15, 2018: Annals of Biomedical Engineering
Arash Abiri, Yichen Ding, Parinaz Abiri, René R Sevag Packard, Vijay Vedula, Alison Marsden, C-C Jay Kuo, Tzung K Hsiai
While virtual reality (VR) has potential in enhancing cardiovascular diagnosis and treatment, prerequisite labor-intensive image segmentation remains an obstacle for seamlessly simulating 4-dimensional (4-D, 3-D + time) imaging data in an immersive, physiological VR environment. We applied deformable image registration (DIR) in conjunction with 3-D reconstruction and VR implementation to recapitulate developmental cardiac contractile function from light-sheet fluorescence microscopy (LSFM). This method addressed inconsistencies that would arise from independent segmentations of time-dependent data, thereby enabling the creation of a VR environment that fluently simulates cardiac morphological changes...
August 15, 2018: Annals of Biomedical Engineering
Dominic Mah, Matthew Henry Pelletier, Vedran Lovric, William Robert Walsh
3D-printing technologies such as electron beam melting (EBM) have allowed for patient-specific orthopaedic implants, however differences generated from the fabrication process may alter the corrosion properties of Ti6Al4V implants. This study evaluated the corrosion characteristics of EBM-fabricated Ti6Al4V, alongside any linked microstructural and surface changes. EBM-fabricated Ti6Al4V and wrought Ti6Al4V specimens (n = 10 per group) underwent microstructural and surface characterisation before and after corrosion testing...
August 15, 2018: Annals of Biomedical Engineering
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