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Over 450,000 Americans suffer from degenerative muscle diseases characterized by loss of strength and dexterity in the human hand. An assistive hand exoskeleton was designed to amplify residual muscle strength and restore functionality by assisting pinching and grasping motions. The device featured three movable digits: thumb, index, and middle-ring-small (MRS) digit. Adjustable straps wrapped around...
4D ultrasound has the potential to provide complex temporal information needed for the proper diagnosis of cardiac pathologies. The objective of this study is to demonstrate a potential pipeline for the clinical evaluation of 4D cardiac strain using only 4D (RT3D) ultrasound data. First, 4D cardiac ultrasound data is collected using a Siemens SC2000 Ultrasound machine. Then, the raw Rho-Theta data...
CD151 plays an important role in the regulation of cell migration, vascular morphogenesis, and cancer metastasis. Many of these processes are related to the strength of cell-matrix attachment. In this study, traction force microscopy (TFM) was used to determine whether knockdown of CD151 in endothelial cells would lead to a significant modification in cell-matrix adhesion. Human dermal microvascular...
Three-dimensional (3D) analysis of the deforming airway during tidal breathing has not been performed in children with obstructive sleep apnea. We used volume-gated magnetic resonance images to segment, surface, and volume mesh the airway of one child with obstructive sleep apnea syndrome (OSAS) and one control. A computational fluid dynamics (CFD) study was performed on each airway at flow rates...
Rotator cuff tears are among the most common shoulder injuries that require surgery. High failure rates of biological graft-based repairs underscore the need for functional alternatives. In this study, effects of nanofiber organization on adhesion of cuff fibroblasts (hRCF) and human mesenchymal stem cells (hMSC) are evaluated. It is hypothesized that fiber alignment will regulate cell morphology...
Rupture of abdominal aortic aneurysm (AAA) ranks as the 13th leading cause of death in the US. Fluid Structure Interaction (FSI) analysis was conducted with the aim of strengthening the current diagnostic measures of the disease, in particular, to (i) predict the location of wall rupture, (ii) estimate the state of pathology from the calculated ruptured potential index (RPI) and (iii) predict the...
The primary cilium, a hair-like projection from the cellular membrane, is involved in fluid flow sensing. In this study, the primary cilium is modeled as a thin beam undergoing large deflection due to fluid drag forces. For the first time, the bending response is analyzed with a model combining large angle rotations with the assumption of a linear drag force along the ciliary length. The model is...
The saliva in dry mouth subjects worked as well as that of the controls in providing lubricity. Their interaction with the saliva substitutes was similar to the behavior of that of the controls with the substitute. Based on the statistical analysis, it is likely that saliva in dry mouth subjects differs from that in normal healthy individuals in quantity alone and not quality.
The application of pressure to one area of skin for an extended period of time may lead to a loss in blood flow. This in turn may lead to the formation of a pressure sore. These could be life threatening and require very expensive negative pressure treatments in order to cure. Pressure sores are a large problem for paraplegics in wheelchairs since they are seated all day and cannot feel anything from...
Electromechanical Wave Imaging (EWI) has recently been introduced as a non-invasive, ultrasound-based imaging modality, which could map the electrical activation of the heart in various echocardiographic planes in mice, dogs and humans in vivo. By acquiring radio-frequency (RF) frames at very high frame rates (390-520Hz), the onset of small, localized, transient deformations resulting from the electrical...
Most current elastography methods remain qualitative or display only strain information due to the inexact internal stress distribution. A more accurate result may be obtained by employing force sensors to gauge the applied vertical compression force on skin surface through the ultrasound transducer. A computationally efficient superposition algorithm based on Love's closed-form equation (SLE) is...
Osteocytes exhibit solid-like viscoelastic behavior in response to mechanical stresses. The goal of this study was to determine the viscoelastic properties of osteocytes using a combined finite element analysis (FE) modeling and experimental approach. The three-dimensional (3D) cell shape of the osteocyte under fluid flow was reconstructed using using a novel pseudo-3D microscopy technique. The cell...
Full length resilin, as well as resilin peptides encoded by exons 1 and 3, were analyzed for structural features. The elasticity mechanisms of resilin related to insect function are described. To approach this goal, a simple energy input method based on thermal treatment was used to detail the transitions and structures of resilin. A systematic pathway to the mechanism was followed based on Temperature-modulated...
Resilin is a polymeric rubber-like protein secreted by insects to specialized cuticle regions, in areas where high resilience and low stiffness are required. Resilin binds to the cuticle polysaccharide chitin via a chitin binding domain and is further polymerized through oxidation of the tyrosine residues resulting in the formation of dityrosine bridges and assembly of a high-performance protein-carbohydrate...
Osseointegration is critical for implant fixation, and mechanical stimuli play a role in this process. Our long term goal is to investigate the relationship between local mechanical environment and osseointegration. In this paper, as a first step in the study, we constructed an approximate 3D model of the in-vivo test and focused on calculating the strain fields around the implant. We first demonstrated...
Neuroimaging via fMRI reveals that the neural networks behind the visual system are one of the most complex systems for processing information regarding the external world. Ocular movements can be classified as conjugate saccadic or disconjugate vergence eye movements. Motor learning is another highly complex function residing in the cortical and subcortical regions of the brain that utilizes both...
During symmetrical vergence movements, saccades are frequently observed. This research tests the hypothesis that the brain initiates a saccade to facilitate a vergence movement when it has slower dynamics. This study analyzes the frequency of saccades in four healthy controls during near and far ranges for both convergence and divergence movements. The experiment suggests that the frequency of saccades...
The research material presented in this paper is a continuation of work done in analyzing impact properties of a biomaterial found in a banana peel. Important energy absorbing characteristics, e.g., plateau stress, locking stress, deformation mode and crushing progression, collapsing mechanism, and crushing stroke of the foam filled (peel) structure are compared with the previously analyzed unfilled...
Vergence eye movements are the inward and outward turning of the eyes and contemporary views believe these movements are mediated by a preprogramming and feedback controlled mechanism. The individual left and right eye responses have been reported to have large dynamic asymmetries between the individual eye movements. One hypothesis to explain the observed asymmetry is the preprogrammed transient...
An enhanced finite element model of the human femur is presented as a reliable mean for prediction of bone failure mechanism for simulations involving frontal impacts. The original finite element representation of femur which was considered in this study did not encompass node connectivity at the interfaces between cortical shaft and condylar regions. Improvements made to the original model have been...
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