Biomechanical Considerations of Refreshable Braille and Tactile Graphics Toward Equitable Access: A Review.

This review highlights the biomechanical foundations of braille and tactile graphic discrimination within the context of design innovations in information access for the blind and low-vision community. Braille discrimination is a complex and poorly understood process that necessitates the coordination of motor control, mechanotransduction, and cognitive-linguistic processing. Despite substantial technological advances and multiple design attempts over the last fifty years, a low-cost, high-fidelity refreshable braille and tactile graphics display has yet to be delivered. Consequently, the blind and low-vision communities are left with limited options for information access. This is amplified by the rapid adoption of graphical user interfaces for human-computer interaction, a move that the blind and low vision community were effectively excluded from. Text-to-speech screen readers lack the ability to convey the nuances necessary for science, technology, engineering, arts, and math education and offer limited privacy for the user. Printed braille and tactile graphics are effective modalities but are time and resource-intensive, difficult to access, and lack real-time rendering. Single- and multiline refreshable braille devices either lack functionality or are extremely cost-prohibitive. Early computational models of mechanotransduction through complex digital skin tissue and the kinematics of the braille reading finger are explored as insight into device design specifications. A use-centered, convergence approach for future designs is discussed in which the design space is defined by both the end-user requirements and the available technology.

Neonatal Noninvasive Ventilation Nasal Mask Interface Pressure and the Inter-Individual Variation of Mask Placement.

BACKGROUND: The 2014 American Academy of Pediatrics recommendation for CPAP as an alternative to mechanical ventilation for treatment of neonatal respiratory distress prompted a rapid shift to noninvasive ventilation (NIV). Since most patients receive nasal bubble CPAP (a form of NIV), a concomitant increase in nasal pressure injuries followed. This prospective observational study aims to develop strategies to reduce nasal mask pressure injury in neonates by 1.) quantifying CPAP mask-interface pressure and 2.) assessing placement variability. METHODS: A 1F MEMS Connect pressure sensor (Millar®) was modified for contact pressure measurements with silicone embedding and calibrated. The CPAP generator and interface components were sized for a 24-week neonatal simulator. Thirteen neonatal ICU staff placed the simulator on CPAP at 6 cmH2O and 8 L/min of flow with no humidification. Pressure was measured at three locations (the forehead, nasal bridge, and philtrum) in triplicate (three measurements per site). Descriptive statistics, a location-specific, one-way analysis of variance (ANOVA) with a Tukey post hoc test, and a two-sample paired t-test of the means of the first and last triplicate were performed (Minitab, LLC). RESULTS: Pressure ranged from 12.3 to 377.3 mmHg. The mean (SD) interface pressure at the philtrum was significantly higher than both the nasal bridge and the forehead (philtrum: 173.9 (101.3), nasal bridge: 67.79 (28.9), and forehead 79.02 (36.87), p ˂ 0.001). CPAP fixation varied, including bonnet placement, trunk angle, mask compression, use of hook and loop extenders, and level of vigorous bubble feedback achieved. CONCLUSIONS: This study developed a modified pressure sensor for quantifying the pressure exerted by a nasal mask on facial skin. Maximum pressures were higher than those previously reported. Inter-individual differences were present in both quantitative and qualitative measures of pressure. Reduction of NIV-associated pressure injuries may be achieved through NIV fixation technique training and improved nasal mask stability and size increments.

Incremental increases in physiological fluid shear progressively alter pathogenic phenotypes and gene expression in multidrug resistant Salmonella.

The ability of bacteria to sense and respond to mechanical forces has important implications for pathogens during infection, as they experience wide fluid shear fluctuations in the host. However, little is known about how mechanical forces encountered in the infected host drive microbial pathogenesis. Herein, we combined mathematical modeling with hydrodynamic bacterial culture to profile transcriptomic and pathogenesis-related phenotypes of multidrug resistant S. Typhimurium (ST313 D23580) under different fluid shear conditions relevant to its transition from the intestinal tract to the bloodstream. We report that D23580 exhibited incremental changes in transcriptomic profiles that correlated with its pathogenic phenotypes in response to these progressive increases in fluid shear. This is the first demonstration that incremental changes in fluid shear forces alter stress responses and gene expression in any ST313 strain and offers mechanistic insight into how forces encountered by bacteria during infection might impact their disease-causing ability in unexpected ways.

Predicting head injury risk during International Space Station increments.

INTRODUCTION: NASA's Human Research Program is using a probabilistic risk assessment approach to identify acute and chronic medical risks to manned spaceflight. The objective of this project was to estimate the likelihood of a neurological head injury to a crewmember severe enough to require medical assessment, treatment, or evacuation during a typical International Space Station (ISS) increment. METHODS: A 2 degree-of-freedom analytical model of the human head was created to allow for analysis of the impact response. The output of the model is acceleration of the head, which was used to determine the probability that the simulated impact resulted in a head injury with an Abbreviated Injury Scale (AIS) score of 3 or greater. These data were then integrated into a probabilistic risk assessment, which outputs a likelihood of injury with a representative measure of the uncertainty. RESULTS: A Monte Carlo simulation was performed to vary input parameters over their defined distributions. The mean probability of a moderate neurological injury (AIS 3 or greater) occurring due to a head impact by a crewmember translating through the ISS is 1.16 x 10(-4) per 6-mo mission increment (2.32 x 10(-4) per year). DISCUSSION: Our head injury prediction model has shown that there is a low, yet not insignificant, probability of neurological head injury of AIS score 3 or greater. The results from this simulation will be input into the parent Integrated Medical Model, which incorporates the risks of over 80 different medical events in order to inform mission planning scenarios.