Peptidomimetic Polymers: Advances in Monomer Design and Polymerization Methods

This work is focused on the design, synthesis and characterization of polypeptide and polypeptoid polymers. The former are composed of amino acid repeat units and possess intramolecular hydrogen bonding interactions allowing for the self-assembly into well-defined secondary structures (e.g. α-helix). Polypeptoids are based on N-alkyl substituted glycine and lack intramolecular hydrogen bonding interactions, resulting in enhanced proteolytic stability and thermal processability. Physicochemical properties of polypeptoids are strongly dependent on the side chain structures, allow for control of the solubility, crystallinity, and conformation of the polymers. Well-defined polypeptides and polypeptoids are synthesized by the ring-opening polymerization (ROP) of their corresponding N-carboxyanhydride monomers (NCA), enabling access to high molecular weight polymers having well-defined structures. Chapter II is focused on the synthesis and characterization of glycopolypeptides by a combination of controlled polymerization methods and copper mediated alkyne/azide cycloaddition chemistry and investigation of the multivalent binding of the glycopolypeptides with Concanavalin A, a model lectin. The focus of the study is on understanding the effect of molecular characteristics of the glycopolypeptides such as chain length, epitope density and backbone conformation on the binding kinetics and stoichiometry. Chapter III is focused on the development of an organo-promoted ring-opening polymerization of N-substituted NCAs using alcohol initiators in conjunction with 1,1,3,3-tetramethylguanidine (TMG), an organic promotor. It was found that TMG activates the alcohols through hydrogen bonding interaction. The activated alcohol moieties can initiate the NCAs polymerizations under mild conditions. It was further revealed that the electronic and steric characteristics of the alcohols impact the initiation efficiency and thus the polymerization behavior. Chapter IV is focused on the synthesis and polymerization of N-thiocarboxyanhydrosulfides (NTA), a mercapto analog of the NCA. NTAs exhibited enhanced moisture-stability but reduced polymerization activities relative to the NCA analogs. Several initiating systems have been uncovered to enable controlled polymerization of NTAs in open air, allowing for access to high molecular weight polypeptides and polypeptoids

Systèmes de soutien des réseaux sociaux scientifiques : Une exploration qualitative des catalyseurs et des obstacles aux nouvelles études en médecine universitaire

Introduction: As academia begins to incorporate modern communication technologies into its scholarly structures, there are both enablers and barriers which foster academics’ uptake of these innovations. Those who are early adopters of academic social media - whether it be for education, research-related networking, or knowledge translation - may therefore be best positioned to highlight both enablers and barriers within their work environments. Methods: The authors conducted a constructivist grounded theory study to discern what prominent practitioners of academic social media (e.g. Twitter) have encountered in their careers. Participants were recruited via a snowball sampling technique and invited to participate in semi-structured interviews. Three investigators engaged in constant comparative analysis of incoming transcripts. To enhance rigour, we conducted an audit of the analysis and a participant member check. Results: Seventeen emerging influencers in the field of academic social media were recruited. After axial coding, the 30 enablers and 21 barriers to academic social media use were mapped to three spheres of influence: personal, institutional, and virtual. The investigators propose a framework that organizes these enablers and barriers around a tipping point where sustainability becomes possible. Conclusions: Multiple enablers and barriers were described to influence social media users within academic medicine. By organizing these facets into a personal, institutional, and virtual framework along a spectrum, we can begin to understand the underlying structures that potentiate the academic ecosystems in which social media and similar innovations may flourish.Introduction : Alors que le milieu universitaire commence à intégrer les technologies de communication modernes dans ses structures d’enseignement, il existe à la fois des facteurs favorables et des obstacles à l’adoption de ces innovations par les chercheurs. Les premiers adoptants des réseaux sociaux scientifiques, que ce soit dans un cadre éducatif, de réseautage lié à la recherche ou d’application des connaissances, sont sans doute les mieux placés pour mettre en évidence aussi bien les facteurs favorables que les facteurs défavorables présents dans leur environnement de travail. Méthodes : Les auteurs ont mené une étude selon la théorisatoin ancrée qui s’inscrit dans un courant constructiviste afin de cibler les éléments de l’expérience d’importants utilisateurs des réseaux sociaux scientifiques (p. ex. Twitter). Les participants ont été recrutés par échantillonnage en boule de neige et invités à des entretiens semi-structurés. Trois chercheurs ont analysé les transcriptions reçues selon la méthode de la comparaison constante. Par souci de rigueur, nous avons procédé à une vérification de l’analyse et à un contrôle des participants. Résultats : Dix-sept influenceurs émergents dans le domaine des réseaux sociaux scientifiques ont été recrutés. Après un codage axial, les 30 catalyseurs et les 21 obstacles à l’utilisation des réseaux sociaux scientifiques ont été mis en correspondance avec trois sphères d’influence : personnelle, institutionnelle et virtuelle. Les chercheurs proposent un cadre qui organise ces catalyseurs et ces obstacles autour d’un point de basculement où la durabilité devient possible. Conclusions : De multiples facilitateurs et obstacles ont été décrits pour influencer les utilisateurs de réseaux sociaux dans le domaine de la médecine universitaire. La classification de ces facteurs sur une échelle par type de cadre (personnel, institutionnel et virtuel) laisse entrevoir les structures sous-jacentes des écosystèmes universitaires qui sont propices au développement des réseaux sociaux et des innovations de ce type

Heteroscedastic Uncertainty for Robust Generative Latent Dynamics

Learning or identifying dynamics from a sequence of high-dimensional observations is a difficult challenge in many domains, including reinforcement learning and control. The problem has recently been studied from a generative perspective through latent dynamics: high-dimensional observations are embedded into a lower-dimensional space in which the dynamics can be learned. Despite some successes, latent dynamics models have not yet been applied to real-world robotic systems where learned representations must be robust to a variety of perceptual confounds and noise sources not seen during training. In this paper, we present a method to jointly learn a latent state representation and the associated dynamics that is amenable for long-term planning and closed-loop control under perceptually difficult conditions. As our main contribution, we describe how our representation is able to capture a notion of heteroscedastic or input-specific uncertainty at test time by detecting novel or out-of-distribution (OOD) inputs. We present results from prediction and control experiments on two image-based tasks: a simulated pendulum balancing task and a real-world robotic manipulator reaching task. We demonstrate that our model produces significantly more accurate predictions and exhibits improved control performance, compared to a model that assumes homoscedastic uncertainty only, in the presence of varying degrees of input degradation.Comment: In IEEE Robotics and Automation Letters (RA-L) and presented at the IEEE International Conference on Intelligent Robots and Systems (IROS'20), Las Vegas, USA, October 25-29, 202

Social Geographies at Play: Mapping the Spatial Politics of Community-Based Youth Sport Participation

Organized youth sports programs (YSP) provide opportunities for participation in physical activity, and represent an important part of the broader public health agenda in the U.S. YSP not only provide physiological health benefits through active participation, but also promote social relationships within communities. In this study, we (1) investigated participants’ travel to access YSP located in neighborhoods historically delineated by an over/under-representation of socio-economic and/or racial diversity; and (2) examined the neighborhood demographics for those YSP participants who traveled the most/least to participate. Five years of demographic and GIS visualization data from participants in a publically-provisioned youth sport league network were analyzed. Significant differences were found between the travel distances of participants in different sports, and between the travel distances of participants from neighborhoods with different racial and/or socio-economic composition. This research expands understanding of the potential segregation effects of community-based YSP for various stakeholder groups

Development Methods and a Scenegraph Animation API for Cluster Driven Immersive Applications

This paper presents a scenegraph animation application programming interface (API), known as the Animation Engine, which was constructed for software developers to easily perform smooth transitions and manipulations to scenegraph nodes. A developer can use one line of code to enter the property, end state and number of frames to describe the animation, then the Animation Engine handles the rest in the background. The goal of the Animation Engine is to provide a simple API that integrates into existing applications with minimal effort. Additionally, techniques to improve virtual reality (VR) application performance on a large computer cluster are presented. These techniques include maintaining high frame rates with 4096 × 4096 pixel textures, eliminating extraneous network traffic and reducing long model loading time. To demonstrate the Animation Engine and the development techniques, an application known as the Virtual Universe was created. The Virtual Universe, designed to run in a six walled CAVE, allows users to freely explore a set of space themed environments. The architecture and development techniques for writing a stable immersive VR application on a large computer cluster, in addition to the creation of the Animation Engine, is presented in this paper

Compliant Lower Body Exoskeleton

ME450 Capstone Design and Manufacturing Experience: Winter 2008Robotic exoskeletons that assist human locomotion are currently comprised of multiple actuators and motors driving link systems. Current designs, such as BLEEX and HAL, are active systems requiring multiple sensors coupled with a computer system that signals the actuators and motors. This project proposes a passive, compliant elastic exoskeleton to be worn in parallel with the entire lower limb. The goal of this project is to design, prototype and test a lower-body elastic exoskeleton that reduces the metabolic cost of human locomotion through a low weight, low-profile compliant mechanism.Michael S. Cherryhttp://deepblue.lib.umich.edu/bitstream/2027.42/58679/1/me450w08project22_report.pd

Community Engagement of Adolescents in the Development of a Patient-Centered Outcomes Tool for Adolescents with a History of Hypospadias Repair

Introduction Hypospadias may lead to long-term issues with urination, sexual function and psychosocial well-being. Limited evidence exists regarding the healthcare communication preferences of male adolescents regarding sensitive topics. Objective The purpose of this qualitative study was to explore the healthcare communication preferences of male adolescents regarding sensitive topics (e.g. urinary and sexual issues) and engage them in in the initial stages of development a patient-centered outcomes tool for adolescents with a history of hypospadias repair. Study Design A multi-disciplinary team with communication design expertise, pediatric urology experts, and health services researchers developed a self-reported toolkit for adolescent patients who had hypospadias repair as children. The toolkit featured short writing/diagramming exercises and scales to facilitate participant reflections about genital appearance, urination, sexual function and psychosocial well-being. We recruited students from two local high schools for two focus groups to obtain feedback about the usability/acceptability of the toolkit’s appearance/content. We inquired about language preferences and preferred format and/or setting for sharing sensitive information with researchers. The focus groups were audio recorded, professionally transcribed, checked for accuracy and analyzed by two coders using qualitative content analysis. Major themes and subthemes were identified and representative quotes were selected. Results We conducted two focus groups in January 2018 with 33 participants, ages 14-18. Participants preferred language that would make patients feel comfortable as well as serious, clinical language rather than slang terms/sexual humor (Extended Summary Table). They recommended avoidance of statements implying that something is wrong with a patient or statements that would pressure the patient into providing answers. They suggested fill-in-the-blank and open-ended responses to encourage freedom of expression and colorful graphics to de-emphasize the test-like appearance of the toolkit. Most participants preferred a toolkit format to a one-on-one interview to discuss sensitive topics such as urinary or sexual issues. Participants would prefer either a male interviewer or would like to have a choice of interviewer gender for individual qualitative interviews, and they recommended a focus group leader with a history of hypospadias repair. Discussion This study provides a rich description of a group of male high school students’ experiences with healthcare providers and researchers. Its qualitative design limits generalizability and our findings may not be similar to adolescents with a history of hypospadias repair. Conclusion We used focus group feedback on the toolkit prototype to refine the tool for use in a future study of adolescents with history of hypospadias repair

The Relationships between Weather-Related Factors and Daily Outdoor Physical Activity Counts on an Urban Greenway

The purpose of this study was to examine relationships between weather and outdoor physical activity (PA). An online weather source was used to obtain daily max temperature [DMT], precipitation, and wind speed. An infra-red trail counter provided data on daily trail use along a greenway, over a 2-year period. Multiple regression analysis was used to examine associations between PA and weather, while controlling for day of the week and month of the year. The overall regression model explained 77.0% of the variance in daily PA (p < 0.001). DMT (b = 10.5), max temp-squared (b = −4.0), precipitation (b = −70.0), and max wind speed (b = 1.9) contributed significantly. Conclusion: Aggregated daily data can detect relationships between weather and outdoor PA