Cardiovascular diseases are the number one cause of death worldwide. Currently, portable battery-operated systems such as mobile phones with wireless ECG sensors have potential to be used in continuous cardiac function assessment that can easily integrated into daily life. These point-of-care diagnostic therefore help unveil and treat cardiovascular diseases. The basis for analysis is a robust detection prominent QRS complex, well other signal characteristics. However, it not clear from...

We examined the shear properties of passive ventricular myocardium in six pig hearts. Samples (3 × 3 mm) were cut from adjacent regions lateral left midwall, with sides aligned principal material axes. Four cycles sinusoidal simple (maximum displacements 0.1–0.5) applied separately to each specimen two orthogonal directions. Resulting forces along three axes measured. Three specimens heart tested different orientations cover all modes deformation. Passive has nonlinear viscoelastic...

Current brain-based visual prostheses pose significant challenges impeding adoption such as the necessarily complex surgeries and occurrence of more substantial side effects due to sensitivity brain. This has led much effort toward vision restoration being focused on approachable part brain - retina. Here we introduce a novel, parameterized simulation platform that enables study human retinal degeneration optimization stimulation strategies. The bears immense potential for patient-specific...

Active multi-electrode arrays are used in vision prostheses, including optic nerve cuffs and cortical retinal implants for stimulation of neural tissue. For implants, with up to 1500 electrodes clinical trials. The ability convey information high spatial resolution is critical these applications. To assess the extent which impaired by electric crosstalk, finite-element simulation field distribution a simplified passive tissue model retina performed. effects electrode size, spacing, distance...

Research to restore some degree of vision patients suffering from retinal degeneration is becoming increasingly more promising. Several groups have chosen electrical stimulation the remaining network a degenerate retina as means generate discrete light percepts (phosphenes). Approaches vary significantly, with greatest difference being location stimulating electrode itself.Suprachoroidal positioning offers excellent mechanical stability and surgical simplicity; however, at cost activation...

To quantify regional three-dimensional (3D) motion and myocardial strain using magnetic resonance (MR) tissue tagging in patients with non-ischemic dilated cardiomyopathy (DCM).MR grid tagged images were obtained multiple short- long-axis planes thirteen DCM patients. Regional 3D displacements strains calculated the aid of a finite element model. Five also imaged after LV volume reduction by partial left ventriculectomy (PLV), combined mitral tricuspid valve repair.DCM showed consistent,...

A lumped parameter model of human cardiovascular-implantable rotary blood pump (iRBP) interaction has been developed based on experimental data recorded in two healthy pigs with the iRBP situ. The includes descriptions left and right heart, direct ventricular through septum pericardium, systemic pulmonary circulations, as well iRBP. subset parameters was optimized a least squares sense to faithfully reproduce measurements (pressures, flows variables). Our fitted compares favorably our at...

We present a computationally efficient three-dimensional bidomain model of torso-embedded whole heart electrical activity, with spontaneous initiation activation in the sinoatrial node, incorporating specialized conduction system heterogeneous action potential morphologies throughout heart. The simplified geometry incorporates as volume source, cavities, lungs, and torso passive conductors. placed four surface electrodes at limbs torso: , six on chest to simulate Einthoven,...

The sulfated marine polysaccharides, fucoidan and λ-carrageenan, are known to possess anti-inflammatory, immunomodulatory, cellular protective properties. Although they hold considerable promise for tissue engineering constructs, their covalent cross-linking in hydrogels comparative bioactivities cells absent from the literature. Thus, λ-carrageenan were modified with methacrylate groups covalently cross-linked synthetic polymer poly(vinyl alcohol)-methacrylate (PVA-MA) form 20 wt %...

A novel shear-test device for soft biological tissue, capable of applying simple shear deformations simultaneously in two orthogonal directions while measuring the resulting forces generated three axes, is described. We validated using a synthetic gel, properties which were ascertained from independent tensile and rotational tests. Material parameters gel fitted neo-Hookean analytical solutions to test data, these matched results device. Preliminary obtained with rat septal myocardium are...

We investigated retinal ganglion cell (RGC) responses to epiretinal electrical stimulation delivered by hexagonally arranged bipolar (Hex) electrodes, in order assess the feasibility of this electrode arrangement for future implant devices. In vitro experiments were performed using rabbit preparations, with results compared a computational model axonal stimulation. Single-unit RGC recorded extracellular microelectrodes. With 100 µs/phase biphasic pulses, threshold charge densities 24.0 ±...

Computational models have become essential in predicting medical device efficacy prior to clinical studies. To investigate the performance of a left-ventricular assist (LVAD), fully-coupled cardiac fluid-electromechanics finite element model was developed, incorporating electrical activation, passive and active myocardial mechanics, as well blood hemodynamics solved simultaneously an idealized biventricular geometry. Electrical activation initiated using simplified Purkinje network with...

The ability for visual prostheses to preferentially activate functionally-distinct retinal ganglion cells (RGCs) is important improving perception. This study investigates the use of high frequency stimulation (HFS) elicit RGC activation, using a closed-loop algorithm search optimal parameters preferential ON and OFF resembling natural physiological neural encoding in response stimuli. We evaluated performance wide range electrical amplitudes frequencies on responses vitro murine...

Assessment of spine alignment is crucial in the management scoliosis, but current auto-analysis suffers from low accuracy. We aim to develop and validate a hybrid model named SpineHRNet+, which integrates artificial intelligence (AI) rule-based methods improve auto-alignment reliability interpretability.From December 2019 November 2020, 1,542 consecutive patients with scoliosis attending two local clinics (The Duchess Kent Children's Hospital at Sandy Bay Hong Kong; Queen Mary Pok Fu Lam on...

False lumen thrombosis (FLT) in type B aortic dissection has been associated with the progression of and treatment outcome. Existing computational models mostly assume rigid wall behavior which ignores effect flap motion on flow thrombus formation within FL. In this study, we have combined a fully coupled fluid-structure interaction (FSI) approach shear-driven model described by series convection-diffusion reaction equations. The integrated FSI-thrombosis applied to an idealized geometry...