Incorporating a Hands-On Device-Based Activity in a Human Factors Biomedical Engineering Course in Sub-Saharan Africa.

A challenge in building the biomedical engineering human factors course at Malawi University of Business and Applied Sciences was integrating meaningful direct experiences with medical products. The instructor also noticed a significant gap between the topics in the course and their surrounding clinical context, a low-income setting. Recognizing that devices should be designed and evaluated in the context of the local users' needs and situations, new hands-on modules were created and implemented in this BME human factors course. Students were asked to critically evaluate and make recommendations to improve the human factors aspects of the software and hardware of the IMPALA, a vital signs monitoring device developed for use in Malawi. Engaging with this medical device, students observed and understood many issues discussed in human factors, including the design of ports, controls, and other user interfaces. The collaboration between the course and the IMPALA project harnessed the local expertise of students to improve the design of a new patient monitoring system. Thus, the IMPALA project itself benefited from this collaboration. Second, students greatly benefited from applying the class concepts to the IMPALA. Students were engaged far more during the interactive components than during the lecture components. Many students successfully translated their knowledge on human factors to their final-year design project.

Objective Communication Patterns Associated With Team Member Effectiveness in Real-World Virtual Teams.

OBJECTIVE: We explore the relationships between objective communication patterns displayed during virtual team meetings and established, qualitative measures of team member effectiveness. BACKGROUND: A key component of teamwork is communication. Automated measures of objective communication patterns are becoming more feasible and offer the ability to measure and monitor communication in a scalable, consistent and continuous manner. However, their validity in reflecting meaningful measures of teamwork processes are not well established, especially in real-world settings. METHOD: We studied real-world virtual student teams working on semester-long projects. We captured virtual team meetings using the Zoom video conferencing platform throughout the semester and periodic surveys comprising peer ratings of team member effectiveness. Leveraging audio transcripts, we examined relationships between objective measures of speaking time, silence gap duration and vocal turn-taking and peer ratings of team member effectiveness. RESULTS: Speaking time, speaking turn count, degree centrality and (marginally) speaking turn duration, but not silence gap duration, were positively related to individual-level team member effectiveness. Time in dyadic interactions and interaction count, but not interaction length, were positively related to dyad-level team member effectiveness. CONCLUSION: Our study highlights the relevance of objective measures of speaking time and vocal turn-taking to team member effectiveness in virtual project-based teams, supporting the validity of these objective measures and their use in future research. APPLICATION: Our approach offers a scalable, easy-to-use method for measuring communication patterns and team member effectiveness in virtual teams and opens the opportunity to study these patterns in a more continuous and dynamic manner.

Advancing pediatric medical device development via non-dilutive NIH SBIR/STTR grant funding.

INTRODUCTION: A shortage of medical devices designed for children persists due to the smaller pediatric population and market factors. Furthermore, pediatric device development is challenging due to the limited available funding sources. We describe our experience with pediatric device projects that successfully received federal grant support towards commercializing the devices that can serve as a guide for future innovators. METHODS: The developmental pathways of pediatric device projects at a tertiary-care children's hospital that received NIH SBIR/STTR funding between 2016-2019 were reviewed. The clinical problems, designs, specific aims, and development phase were delineated. RESULTS: Pediatric faculty successfully secured NIH SBIR/STTR funding for five pediatric devices via qualified small business concerns (SBC's). Three projects were initiated in the capstone engineering design programs and developed further at two affiliated engineering schools, while the other two projects were developed in the faculty members' labs. Four projects received funding via established SBC's, while one was awarded funding via a newly established SBC. CONCLUSION: NIH SBIR/STTR grants are an essential source of external non-dilutive funding for pediatric device innovation and especially for academic-initiated projects. This funding can provide needed early-stage support to facilitate commercialization. In addition, these grants can serve as achievable accomplishments for pediatric faculty portfolios toward academic promotion. Our experience shows that it is possible to build a robust innovation ecosystem comprised of academic faculty (clinical/engineering) collaborating with local device development companies while jointly implementing a product development strategy leveraging NIH SBIR/STTR funding for critical translational research phases of pediatric device development.

Regional diaphragm volume displacement is heterogeneous in dogs.

Muscle shortening and volume displacement (VD) are critical determinants of the pressure-generating capacity of the diaphragm. The present study was designed to test the hypothesis that diaphragm VD is heterogeneous and that distribution of VD is dependent on regional muscle shortening, posture, and the level of muscle activation. Radioopaque markers were sutured along muscle bundles of the peritoneal surface of the crural, dorsal costal, midcostal, and ventral costal regions of the left hemidiaphragm in four dogs. The markers were followed by biplanar video fluoroscopy during quiet spontaneous breathing, passive inflation to total lung capacity (TLC), and inspiratory efforts against an occluded airway at three lung volumes spanning the vital capacity [functional residual capacity, functional residual capacity + ½ inspiratory capacity, and TLC in both the prone and supine postures]. Our data show the ventral costal diaphragm had the largest VD and contributed nearly two times to the total diaphragm VD compared with the dorsal costal portion. In addition, the ventral costal diaphragm contributed nearly half of the total VD in the prone position, whereas it only contributed a quarter of the total VD in the supine postition. During efforts against an occluded airway and during passive inflation to TLC in the supine position, the crural diaphragm displaced volume equivalent to that of the midcostal portion. Regional muscle shortening closely matched regional VD. We conclude that the primary force generator of the diaphragm is primarily dominated by the contribution of the ventral costal region to its VD.

Open-source three-dimensional printing of biodegradable polymer scaffolds for tissue engineering.

The fabrication of scaffolds for tissue engineering requires elements of customization depending on the application and is often limited due to the flexibility of the processing technique. This investigation seeks to address this obstacle by utilizing an open-source three-dimensional printing (3DP) system that allows vast customizability and facilitates reproduction of experiments. The effects of processing parameters on printed poly(ε-caprolactone) scaffolds with uniform and gradient pore architectures have been characterized with respect to fiber and pore morphology and mechanical properties. The results demonstrate the ability to tailor the fiber diameter, pore size, and porosity through modification of pressure, printing speed, and programmed fiber spacing. A model was also used to predict the compressive mechanical properties of uniform and gradient scaffolds, and it was found that modulus and yield strength declined with increasing porosity. The use of open-source 3DP technologies for printing tissue-engineering scaffolds provides a flexible system that can be readily modified at a low cost and is supported by community documentation. In this manner, the 3DP system is more accessible to the scientific community, which further facilitates the translation of these technologies toward successful tissue-engineering strategies.

Computer-aided tissue engineering: benefiting from the control over scaffold micro-architecture.

Minimization schema in nature affects the material arrangements of most objects, independent of scale. The field of cellular solids has focused on the generalization of these natural architectures (bone, wood, coral, cork, honeycombs) for material improvement and elucidation into natural growth mechanisms. We applied this approach for the comparison of a set of complex three-dimensional (3D) architectures containing the same material volume but dissimilar architectural arrangements. Ball and stick representations of these architectures at varied material volumes were characterized according to geometric properties, such as beam length, beam diameter, surface area, space filling efficiency, and pore volume. Modulus, deformation properties, and stress distributions as contributed solely by architectural arrangements was revealed through finite element simulations. We demonstrated that while density is the greatest factor in controlling modulus, optimal material arrangement could result in equal modulus values even with volumetric discrepancies of up to 10%. We showed that at low porosities, loss of architectural complexity allows these architectures to be modeled as closed celled solids. At these lower porosities, the smaller pores do not greatly contribute to the overall modulus of the architectures and that a stress backbone is responsible for the modulus. Our results further indicated that when considering a deposition-based growth pattern, such as occurs in nature, surface area plays a large role in the resulting strength of these architectures, specifically for systems like bone. This completed study represents the first step towards the development of mathematical algorithms to describe the mechanical properties of regular and symmetric architectures used for tissue regenerative applications. The eventual goal is to create logical set of rules that can explain the structural properties of an architecture based solely upon its geometry. The information could then be used in an automatic fashion to generate patient-specific scaffolds for the treatment of tissue defects.

Scaffold pore space modulation through intelligent design of dissolvable microparticles.

The goal of this area of research is to manipulate the pore space of scaffolds through the application of an intelligent design concept on dissolvable microparticles. To accomplish this goal, we developed an efficient and repeatable process for fabrication of microparticles from multiple materials using a combination of rapid prototyping (RP) and soft lithography. Phase changed 3D printing was used to create masters for PDMS molds. A photocrosslinkable polymer was then delivered into these molds to make geometrically complex 3D microparticles. This repeatable process has demonstrated to generate the objects with greater than 95% repeatability with complete pattern transfer. This process was illustrated for three different shapes of various complexities. The shapes were based on the extrusion of 2D shapes. This may allow simplification of the fabrication process in the future combined with a direct transfer of the findings. Altering the shapes of particles used for porous scaffold fabrication will allow for tailoring of the pore shapes, and therefore their biological function within a porous tissue engineering scaffold. Through permeation experiments, we have shown that the pore geometry may alter the permeability coefficient of scaffolds while influencing mechanical properties to a lesser extent. By selecting different porogen shapes, the nutrition transport and scaffold degradation can be significantly influenced with minimal effect on the mechanical integrity of the construct. In addition, the different shapes may allow a control of drug release by modifying their surface-to-volume ratio, which could modulate drug delivery over time. While soft lithography is currently used with photolithography, its high precision is offset by high cost of production. The employment of RP to a specific resolution offers a much less expensive alternative with increased throughput due to the speed of current RP systems.

Diaphragm curvature modulates the relationship between muscle shortening and volume displacement.

During physiological spontaneous breathing maneuvers, the diaphragm displaces volume while maintaining curvature. However, with maximal diaphragm activation, curvature decreases sharply. We tested the hypotheses that the relationship between diaphragm muscle shortening and volume displacement (VD) is nonlinear and that curvature is a determinant of such a relationship. Radiopaque markers were surgically placed on three neighboring muscle fibers in the midcostal region of the diaphragm in six dogs. The three-dimensional locations were determined using biplanar fluoroscopy and diaphragm VD, curvature, and muscle shortening were computed in the prone and supine postures during spontaneous breathing (SB), spontaneous inspiration efforts after airway occlusion at lung volumes ranging from functional residual capacity (FRC) to total lung capacity, and during bilateral maximal phrenic nerve stimulation at those same lung volumes. In supine dogs, diaphragm VD was approximately two- to three-fold greater during maximal phrenic nerve stimulation than during SB. The contribution of muscle shortening to VD nonlinearly increases with level of diaphragm activation independent of posture. During submaximal diaphragm activation, the contribution is essentially linear due to constancy of diaphragm curvature in both the prone and supine posture. However, the sudden loss of curvature during maximal bilateral phrenic nerve stimulation at muscle shortening values greater than 40% (ΔL/L(FRC)) causes a nonlinear increase in the contribution of muscle shortening to diaphragm VD, which is concomitant with a nonlinear change in diaphragm curvature. We conclude that the nonlinear relationship between diaphragm muscle shortening and its VD is, in part, due to a loss of its curvature at extreme muscle shortening.