Conventional lower-limb mechanical models were originally developed for gait analysis of ablebodied Conventional lower-limb mechanical models were originally developed for gait analysis of ablebodied subjects and therefore potentially misrepresent prosthetic foot behavior when applied to modern energy storage and return (ESAR) prostheses. This review investigates the limitations of current models of prosthetic foot dynamics and kinematics. The Scopus online database was used to identify 236 articles on prosthetic foot behavior during either experiments or simulations, categorized into three main types of models: 74% (n = 175) of studies featured a rigid-link model, 17% (n = 39) a lumped-parameter model and 10% (n = 23) finite element (FE) analysis. Notably, 64% (n = 152) of the studies used a conventional two-link segment model, yet only 8% (n = 20) featured the rigid, articulating prosthesis that satisfies this model's underlying rigid-body mechanics assumptions. Conversely, the available preliminary studies on multi-link segment, lumped-parameter and FE models present viable and more mechanically relevant alternatives to conventional techniques, particularly for ESAR prostheses. Expanding these alternative models to include inertial behavior, multiple-degrees of freedom and standardization of boundary conditions will lead towards both accurate and standardized prosthetic foot analysis.

Recent work has pointed to the advantages of using distorted reality to foster sensorimotor adaptations. Here we evaluate the extent to which a visuomotor discrepancy created within the large CAVE2 Hybrid Reality Environment might induce an adaptive effect in walking. This experiment specifically studied the consequences of exposure to a rotational gain that made it appear as though the subjects were turning more than actual by a ratio of 3 to 2. We then studied subjects' abilities make turns while blindfolded before and after the experience. This brief training period (~5 minutes) resulted in slightly larger turns. Such rapid adaptive responses can be interpreted as an alteration of the motor plan and possibly a recalibration of proprioceptive and vestibular senses caused by the alteration of visual input. This study provides preliminary evidence of the possibilities of using distorted reality to constructively enhance motor training and rehabilitation.

Sleep and sleep-related problems play a role in a large number of human disorders and affect every field of medicine. It is estimated that 50 to 70 million Americans suffer from a chronic sleep disorder, which hinders their daily life, affects their health, and confers a significant economic burden to society. The negative public health consequences of sleep disorders are enormous and could have long-term effects, including increased risk of hypertension, diabetes, obesity, heart attack, stroke and in some cases death. Polysomnographic modalities can monitor sleep cycles to identify disrupted sleep patterns, adjust the treatments, increase therapeutic options and enhance the quality of life of recording the electroencephalogram (EEG), electromyogram (EMG) and electrocardiogram (ECG). Although the skills acquired by medical facilitators are quite extensive, it is just as important for them to have access to an assortment of technologies and to further improve their monitoring and treatment capabilities. Computer-aided analysis is one advantageous technique that could provide quantitative indices for sleep disorder screening. Evolving evidence suggests that Parkinson's disease may be associated with rapid eye movement sleep behavior disorder (RBD). With this article, we are reviewing studies that are related to EMG signal analysis for detection of neuromuscular diseases that result from sleep movement disorders. As well, the article describes the recent progress in analysis of EMG signals using temporal analysis, frequency-domain analysis, time-frequency, and sparse representations, followed by the comparison of the recent research.

Myocardial infarction (MI) causes massive heart muscle death and remains a leading cause of death in the world. Cardiac tissue engineering aims to replace the infarcted tissues with functional engineered heart muscles or revitalize the infarcted heart by delivering cells, bioactive factors, and/or biomaterials. One major challenge of cardiac tissue engineering and regeneration is the establishment of functional perfusion and structure to achieve timely angiogenesis and effective vascularization, which are essential to the survival of thick implants and the integration of repaired tissue with host heart. In this paper, we review four major approaches to promoting angiogenesis and vascularization in cardiac tissue engineering and regeneration: delivery of pro-angiogenic factors/molecules, direct cell implantation/cell sheet grafting, fabrication of prevascularized cardiac constructs, and the use of bioreactors to promote angiogenesis and vascularization. We further provide a detailed review and discussion on the early perfusion design in nature-derived biomaterials, synthetic biodegradable polymers, tissue-derived acellular scaffolds/whole hearts, and hydrogel derived from extracellular matrix. A better understanding of the current approaches and their advantages, limitations, and hurdles could be useful for developing better materials for future clinical applications.

Tarsometatarsal (TMT) dislocations are an uncommon but debilitating athletic injury. When symptomatic midfoot instability persists, an injured athlete frequently requires surgical stabilization and rehabilitation for up to 9 months before returning to full athletic participation. Unfortunately, the limited biomechanical knowledge of this injury prevents prophylactic measures from being developed that could reduce an athlete's risk of injury. The goal of this article is to summarize the literature on TMT dislocations, with a particular emphasis on the relevant biomechanics, in an attempt to clarify the circumstances and mechanisms under which these injuries occur. Since athletic injuries represent only a small portion of all TMT dislocations, other categories of injuries are also considered for the insight they provide. This review first summarizes the anatomy of the TMT joint as well as the clinical details surrounding TMT dislocations. The various hypothesized injury mechanisms are then reviewed with particular attention given to cadaveric studies that investigate these mechanisms. Based on this critical review, gaps in the research related to epidemiologic data, full-scale and component testing, numerical modeling, and countermeasure development, are identified. Only by improving our understanding of the causes and biomechanics can steps be taken to protect athletes from these injuries.

Magnetic resonance imaging and magnetic resonance spectroscopy are noninvasive diagnostic techniques based on the phenomenon of nuclear magnetic resonance. Radiofrequency coils are key components in both the transmission and receiving phases of magnetic resonance systems. Transmitter coils have to produce a highly homogeneous alternating field in a wide field of view, whereas receiver coils have to maximize signal detection while minimizing noise. Development of modern magnetic resonance coils often is based on numerical methods for simulating and predicting coil performance. Numerical methods allows the behavior of the coil in the presence of realistic loads to be simulated and the coil's efficiency at high magnetic fields to be investigated. After being built, coils have to be characterized in the laboratory to optimize their setting and performance by extracting several quality indices. Successively, coils performance has to be evaluated in a scanner using standardized image quality parameters with phantom and human experiments. This article reviews the principles of radiofrequency coils, coil performance parameters, and their estimation methods using simulations, workbench, and magnetic resonance experiments. Finally, an overview of future developments in radiofrequency coils technology is included.

Airway hyperresponsiveness is a hallmark of asthma in which airways narrow excessively in response to an agonist, resulting in difficulty in breathing. Constriction of the smooth muscle that spirals around the airways is the principle cause of airway narrowing during an asthma attack. It is likely that several mechanisms are involved in the development of a hyperresponsive airway in asthma. In this review, we focus on the structural and functional aspects that govern the narrowing of a single airway within a lung, then we review the current understanding of how these factors become altered in a way that leads to the airway hyperresponsiveness observed in asthma. We first examine airway caliber as a simple equilibrium of forces favoring narrowing and the forces opposing this narrowing. We then review the role that the dynamic forces of tidal breathing and deep inspirations have across all length scales of the respiratory system; we describe an intriguing inconsistency that has arisen from these data. Finally, we examine the interaction between airway remodeling and inflammation and their roles in health and disease.