Development and Assessment of an Impact Apparatus and High-Speed Camera Motion Tracking System to Quantify the Effect of Static Muscle Loads on Fracture Threshold Measures in the Distal Radius

Distal radius fractures are prevalent, debilitating, and costly. This thesis conducts an in vitro investigation of these injuries, examining the role of static muscle loading on fracture threshold measures (i.e., force, impulse, energy). Initially, an impact apparatus and custom LabVIEW colour-thresholding program were designed and assessed for repeatability and accuracy in quantifying fracture measures and impact kinematics. These tools were then used to test six pairs of cadaveric forearms, with static muscle loads simulated in one specimen from each pair. Distal radius fractures were achieved in 5 pairs, with perilunate dislocations in the remaining pair. None of the fracture threshold measures assessed presented differences attributed to the muscle forces applied. With the appropriate impact apparatus and colour-thresholding techniques now developed and validated, future testing will examine the effects of higher muscle loads to determine if they may have an effect of the fracture threshold of the distal radius

An In-Silico Assessment of Stemless Shoulder Arthroplasty: from CT to Predicted Bone Response

Despite the emergence of stemless humeral implants that utilize short fixation features to gain purchase solely in the metaphysis, the literature contains little information regardingthe morphology and mechanical properties of the humerus’ proximal trabecular-canal, and how stemless implants impact bone response. The present work employs in-silicotools, including CT-based and Finite Element (FE) methods, to define parameters that may influence stemless implant design. The density and morphology of the proximal humerus were assessed using CT-derived point clouds of the trabecular-canal. Bone density was found to diminish 15-20mm beneath the humeral head resection and was greater peripherally. The depth, path and bounding diameters of the proximal trabecular-canal were also quantified and established the spatial constraints in which implants should be designed. To address the lack of consensus regarding the FE modelling of humeral trabecular- stiffness, eight (8) FE models were constructed then duplicated six different trabecular- stiffness relationships. The deviation induced in FE outcomes by stiffness relationship selection was quantified. It was determined that inhomogeneous stiffness definition is important; however, the anatomic site from which the stiffness is defined induced minor deviations in the implant-bone contact area, the change in bone stresses and the potential bone response following stemless reconstruction. Finally, with humeral FE modelling parameters defined, a series of ten generic stemless implants were designed with fixation features that were primarily central, peripheral or boundary-crossing. A population of five (5) cadaveric humeral FE models were constructed for each implant. Tradeoffs were found, with central implants producing the least resorbing potential, and peripheral implants maintaining the most implant-bone contact. Regardless of fixation feature design, predicted bone changes were most prominent within the lateral quadrant of the humerus, directly beneath the humeral head resection. The present work advances the understanding of stemless humeral arthroplasty. The morphological parameters defined provide a spatial definition of the region in which stemless implants function. Through the development of humeral FE models, general trends in bone response following stemless reconstruction were noted; along with tradeoffs regarding the placement of stemless fixation features. These methods can be applied in the design of future stemless implants

Yaaaas Queen! – Daenerys Targaryen As A Contemporary Feminist

This essay examines Daenerys Targaryen from Game of Thrones through the lens of contemporary feminism. Her character’s use of the systems available to her to change those same systems represents contemporary feminist characteristics, while also helping to shape and drive contemporary feminism into a more solidified theory and movement. In her journey from property to queen, Daenerys gains agency through sexual control, then uses that agency to create opportunity for others, ultimately freeing her people from oppression. At times, she steps close to white saviorism, but she confronts her privilege and recognizes the need for intersectional politics for her followers. She redefines what it means to be a woman through stepping into traditionally male-specific positions, and she refocuses the concepts of violence and power to reflect a feminine ‘power-to’ structure, rather than masculine ‘power-over’ one. Daenerys utilizes the contemporary feminist focus on intersectionality and media, giving contemporary feminists a figure to look to when attempting to achieve these goals in our world, by gaining her own agency, rejecting the male-dominance that has shaped her life, creating agency for others to choose their own path, and refocusing the concepts of power, class, and violence to further the goals of feminism overall

Availability and nutrient content of common arthropod prey of northern bobwhites (Colinus virginianus) in western Oklahoma

Variation in the relative abundance and biomass of arthropods, as well as individual variation in macronutrient and elemental content, have important potential consequences for insectivores. We studied the influence of seasonality and habitat management (i.e. burning and strip disking) on the availability of potential arthropod prey for brooding northern bobwhites (Colinus virginianus), and tested variation in macronutrient and elemental content between and within common orders of prey. Burning changed the biomass composition of the arthropod community, but disking did not result in any community-level changes. Burning also increased the total abundance and biomass of arthropods collected compared to the control, but disking did not affect total abundance or biomass. Seasonality exerted a broader influence on arthropods, and total abundance and biomass increased throughout the duration of the sampling period (May-July) at burned/paired control and disked/paired control sites. Ants, which had the highest abundance and biomass of any taxa, appeared to drive these patterns. The response of individual orders to management and seasonality varied in size and direction, though we observed more and stronger effects of seasonality than burning or disking. These results support the idea that burning provides benefits to foraging bobwhite broods through increased total availability of arthropod prey, as well as favorable habitat characteristics (i.e. bare ground, structural heterogeneity). However, large seasonal variation in total arthropod abundance and biomass, as well as that of individual orders, likely influences the relative importance of individual prey items in the bobwhite diet based on the timing of nest initiation and hatching, and temporal shifts are particularly important given variation in nutrient content displayed by arthropod taxa. We found that common orders of prey (Hymenoptera and Coleoptera) had high exoskeleton and low protein content, suggesting that the most available prey are also poor quality. Other orders, like Araneae and Orthoptera, had low exoskeleton and high protein content, suggesting that bobwhite chicks benefit from maintaining high diet diversity. Thus, a better understanding of existing variation in arthropod availability and nutrient content is critical for elucidating the role of prey selection and nutrient uptake in shaping the success of avian insectivores

Quantitative Computed Tomography (QCT) derived Bone Mineral Density (BMD) in finite element studies: a review of the literature

© 2016, The Author(s). Background: Finite element modeling of human bone provides a powerful tool to evaluate a wide variety of outcomes in a highly repeatable and parametric manner. These models are most often derived from computed tomography data, with mechanical properties related to bone mineral density (BMD) from the x-ray energy attenuation provided from this data. To increase accuracy, many researchers report the use of quantitative computed tomography (QCT), in which a calibration phantom is used during image acquisition to improve the estimation of BMD. Since model accuracy is dependent on the methods used in the calculation of BMD and density-mechanical property relationships, it is important to use relationships developed for the same anatomical location and using the same scanner settings, as these may impact model accuracy. The purpose of this literature review is to report the relationships used in the conversion of QCT equivalent density measures to ash, apparent, and/or tissue densities in recent finite element (FE) studies used in common density-modulus relationships. For studies reporting experimental validation, the validation metrics and results are presented. Results: Of the studies reviewed, 29% reported the use of a dipotassium phosphate (K2HPO4) phantom, 47% a hydroxyapatite (HA) phantom, 13% did not report phantom type, 7% reported use of both K2HPO4 and HA phantoms, and 4% alternate phantom types. Scanner type and/or settings were omitted or partially reported in 31% of studies. The majority of studies used densitometric and/or density-modulus relationships derived from different anatomical locations scanned in different scanners with different scanner settings. The methods used to derive various densitometric relationships are reported and recommendations are provided toward the standardization of reporting metrics. Conclusions: This review assessed the current state of QCT-based FE modeling with use of clinical scanners. It was found that previously developed densitometric relationships vary by anatomical location, scanner type and settings. Reporting of all parameters used when referring to previously developed relationships, or in the development of new relationships, may increase the accuracy and repeatability of future FE models

Optimizing Privacy Policy Videos to Mitigate the Privacy Policy Paradox

This research takes a design science approach to improving privacy policies through the design and use of mediated content, such as video. Research has emerged to indicate that privacy policies communicated through video (separate from-”and in addition to-”traditional textual privacy policy documents) are more effective at engendering trust, decreasing perceived risk, and encouraging information disclosure than textual privacy policies, which are seldom read or understood. We extend this research by examining design factors such as narrator gender, animation style, music tone, and color scheme. We implemented a field experiment and survey to determine how variations in these design elements affect consumers’ perceived risk, perceived benefits, and disclosure decisions. The results indicate that the most effective privacy policy videos use female narrators with vibrant color palettes and light musical tones. The animation style (animated imagery versus animated text) has no effect on consumers’ perceived risk/benefits or disclosure decisions

Oxygen ion dynamics in the Earth's ring current: Van Allen probes observations

Oxygen (O+) enhancements in the inner magnetosphere are often observed during geomagnetically active times, such as geomagnetic storms. In this study, we quantitatively examine the difference in ring current dynamics with and without a substantial O+ ion population based on almost 6 years of Van Allen Probes observations. Our results have not only confirmed previous finding of the role of O+ ions to the ring current but also found that abundant O+ ions are always present during large storms when sym-H < -60 nT without exception, whilst having the pressure ratio () between O+ and proton (H+) larger than 0.8 and occasionally even larger than 1 when L < 3. Simultaneously, the pressure anisotropy decreases with decreasing sym-H and increasing L shell. The pressure anisotropy decrease during the storm main phase is likely related to the pitch angle isotropization processes. In addition, we find that increases during the storm main phase and then decreases during the storm recovery phase, suggesting faster buildup and decay of O+ pressure compared to H+ ions, which are probably associated with some species dependent source and/or energization as well as loss processes in the inner magnetosphere.Accepted manuscrip

Artificial intelligence for automated detection of diabetic foot ulcers: A real-world proof-of-concept clinical evaluation

Objective: Conduct a multicenter proof-of-concept clinical evaluation to assess the accuracy of an artificial intelligence system on a smartphone for automated detection of diabetic foot ulcers. Methods: The evaluation was undertaken with patients with diabetes (n = 81) from September 2020 to January 2021. A total of 203 foot photographs were collected using a smartphone, analysed using the artificial intelligence system, and compared against expert clinician judgement, with 162 images showing at least one ulcer, and 41 showing no ulcer. Sensitivity and specificity of the system against clinician decisions was determined and inter- and intra-rater reliability analysed. Results: Predictions/decisions made by the system showed excellent sensitivity (0.9157) and high specificity (0.8857). Merging of intersecting predictions improved specificity to 0.9243. High levels of inter- and intra-rater reliability for clinician agreement on the ability of the artificial intelligence system to detect diabetic foot ulcers was also demonstrated (Kα > 0.8000 for all studies, between and within raters). Conclusions: We demonstrate highly accurate automated diabetic foot ulcer detection using an artificial intelligence system with a low-end smartphone. This is the first key stage in the creation of a fully automated diabetic foot ulcer detection and monitoring system, with these findings underpinning medical device development

Feller Processes: The Next Generation in Modeling. Brownian Motion, L\'evy Processes and Beyond

We present a simple construction method for Feller processes and a framework for the generation of sample paths of Feller processes. The construction is based on state space dependent mixing of L\'evy processes. Brownian Motion is one of the most frequently used continuous time Markov processes in applications. In recent years also L\'evy processes, of which Brownian Motion is a special case, have become increasingly popular. L\'evy processes are spatially homogeneous, but empirical data often suggest the use of spatially inhomogeneous processes. Thus it seems necessary to go to the next level of generalization: Feller processes. These include L\'evy processes and in particular Brownian motion as special cases but allow spatial inhomogeneities. Many properties of Feller processes are known, but proving the very existence is, in general, very technical. Moreover, an applicable framework for the generation of sample paths of a Feller process was missing. We explain, with practitioners in mind, how to overcome both of these obstacles. In particular our simulation technique allows to apply Monte Carlo methods to Feller processes.Comment: 22 pages, including 4 figures and 8 pages of source code for the generation of sample paths of Feller processe