Significant Objects as Metaphor for Home

ABSTRACT Wilcox, Alison. Significant Objects as Metaphor for Home. Unpublished Master of Arts Thesis, University of Northern Colorado, 2020. This qualitative Arts-Based Research investigated how certain objects come to embody a personal definition of home. Objects that are treasured and are associated with home were defined in this research as significant objects. As the researcher, I selected personally significant objects to study. These objects were studied through still life painting and interviews, based on the work of Barbara Fish (2017). Data were then refined into a final reflection painting. This study indicated that significant objects are often denied their intended function, are tied to idealized memories, and help to reconnect the owner to confidence that may have been lost with the passing of time

Geometric parameterisation of pelvic bone and cartilage in contact analysis of the natural hip: an initial study

Parameterised finite element models of the human hip have the potential to allow controlled analysis of the effect of individual geometric features on the contact mechanics of the joint. However, the challenge lies in defining a set of parameters which sufficiently capture the joint geometry in order to distinguish between individuals. In this study, a simple set of parameters to describe the geometries of acetabulum and cartilage in the hip were extracted from two segmentation-based models, which were then used to generate the parameterised finite element models for the two subjects. The contact pressure and contact area at the articular surface predicted from the parameterised finite element models were compared with the results from the segmentation-based models. The differences in the predicted results between the parameterised models and segmentation-based models were found to be within 11% across seven activities simulated. In addition, the parameterised models were able to replicate features of the contact pressure/area fluctuations over the loading cycle that differed between the two subjects. These results provide confidence that the parameterised approach could be used to generate representative finite element models of the human hip for contact analysis. Such a method has the potential to be used to systematically evaluate geometric features that can be captured from simple clinical measurements and provide a cost- and time-effective approach for stratification of the acetabular geometries in the patient population

Short-term genome stability of serial Clostridium difficile ribotype 027 isolates in an experimental gut model and recurrent human disease

Copyright: © 2013 Eyre et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedClostridium difficile whole genome sequencing has the potential to identify related isolates, even among otherwise indistinguishable strains, but interpretation depends on understanding genomic variation within isolates and individuals.Serial isolates from two scenarios were whole genome sequenced. Firstly, 62 isolates from 29 timepoints from three in vitro gut models, inoculated with a NAP1/027 strain. Secondly, 122 isolates from 44 patients (2–8 samples/patient) with mostly recurrent/on-going symptomatic NAP-1/027 C. difficile infection. Reference-based mapping was used to identify single nucleotide variants (SNVs).Across three gut model inductions, two with antibiotic treatment, total 137 days, only two new SNVs became established. Pre-existing minority SNVs became dominant in two models. Several SNVs were detected, only present in the minority of colonies at one/two timepoints. The median (inter-quartile range) [range] time between patients’ first and last samples was 60 (29.5–118.5) [0–561] days. Within-patient C. difficile evolution was 0.45 SNVs/called genome/year (95%CI 0.00–1.28) and within-host diversity was 0.28 SNVs/called genome (0.05–0.53). 26/28 gut model and patient SNVs were non-synonymous, affecting a range of gene targets.The consistency of whole genome sequencing data from gut model C. difficile isolates, and the high stability of genomic sequences in isolates from patients, supports the use of whole genome sequencing in detailed transmission investigations.Peer reviewe

Dynamic virtual simulation of the occurrence and severity of edge loading in hip replacements associated with variation in the rotational and translational surgical position

Variation in the surgical positioning of total hip replacement can result in edge loading of the femoral head on the rim of the acetabular cup. Previous work has reported the effect of edge loading on the wear of hip replacement bearings with a fixed level of dynamic biomechanical hip separation. Variations in both rotational and translational surgical positioning of the hip joint replacement combine to influence both the biomechanics and the tribology including the severity of edge loading, the amount of dynamic separation, the force acting on the rim of the cup and the resultant wear and torque acting on the cup. In this study, a virtual model of a hip joint simulator has been developed to predict the effect of variations in some surgical positioning (inclination and medial-lateral offset) on the level of dynamic separation and the contact force of the head acting on the rim as a measure of severity of edge loading. The level of dynamic separation and force acting on the rim increased with increased translational mismatch between the centres of the femoral head and the acetabular cup from 0 to 4 mm and with increased cup inclination angle from 45° to 65°. The virtual model closely replicated the dynamics of the experimental hip simulator previously reported, which showed similar dynamic biomechanical trends, with the highest level of separation being found with a mismatch of 4 mm between the centres of the femoral head and acetabular cup and 65° cup inclination angle

Three subject-specific human tibiofemoral joint finite element models: complete three-dimensional imaging (CT & MR), experimental validation and modelling dataset.

This dataset includes the experimental data, three-dimensional imaging, computational models and study data from work validating three subject-specific human tibiofemoral joint finite element models. This work forms part of a wider project developing in vitro and in silico pre-clinical testing methods for tissue preserving treatments of the knee joint. The aim of the related study was to provide validation of contact mechanics outputs for specimen-specific tibiofemoral joint models and specifically investigate the need for subject-specific shape representation for the cartilage and meniscus tissues. The dataset provides a complete set of imaging, experimental and computational data for replication of the study. To maximum the potential for re-use the dataset includes imaging and experimental data, which was collected alongside the immediate study data, but not used in that work. Magnetic resonance imaging of the knee joints in their intact state is included, using eight different imaging sequences. Micro computed tomography imaging of the distal femur and proximal tibia after dissection and testing are also provided for all three knee joints. The experimental data includes pressure sensor measurements taken from the tibial cartilage surface at multiple knee joint flexion angles and photographs taken during dissection, potting and loading of the joints. The computational models are provided for all cases performed for the validation and sensitivity testing study, along with the associated results

The effect of collagen fibril orientation on the biphasic mechanics of articular cartilage

The highly inhomogeneous distribution of collagen fibrils may have important effects on the biphasic mechanics of articular cartilage. However, the effect of the inhomogeneity of collagen fibrils has mainly been investigated using simplified three-layered models, which may have underestimated the effect of collagen fibrils by neglecting their realistic orientation. The aim of this study was to investigate the effect of the realistic orientation of collagen fibrils on the biphasic mechanics of articular cartilage. Five biphasic material models, each of which included a different level of complexity of fibril reinforcement, were solved using two different finite element software packages (Abaqus and FEBio). Model 1 considered the realistic orientation of fibrils, which was derived from diffusion tensor magnetic resonance images. The simplified three-layered orientation was used for Model 2. Models 3–5 were three control models. The realistic collagen orientations obtained in this study were consistent with the literature. Results from the two finite element implementations were in agreement for each of the conditions modelled. The comparison between the control models confirmed some functions of collagen fibrils. The comparison between Models 1 and 2 showed that the widely-used three-layered inhomogeneous model can produce similar fluid load support to the model including the realistic fibril orientation; however, an accurate prediction of the other mechanical parameters requires the inclusion of the realistic orientation of collagen fibrils.</p

Dynamic acetabular cup orientation during gait: a study of fast and slow walking total hip replacement patients

The dynamic orientation of total hip replacement acetabular cups during walking may vary sub-stantially from their assumed position at surgical implantation and may vary between individuals. The scale of this effect is of interest for both pre-clinical device testing and for pre-operative sur-gical planning. This work aimed to evaluate: 1) patient variation in dynamic cup orientation; 2) whether walking speed was a candidate proxy measure for the dynamic cup orientation; and 3) the relationships between dynamic cup orientation angles and planar pelvic angles. Pelvic movement data for patients with fast (n=20) and slow (n=19) self-selected walking speeds, was used to calcu-late acetabular cup inclination and version angles through gait. For aim 1, the range and extremes of acetabular cup orientation angles were analysed for all patients. Large patient to patient varia-tion was found in the range of both inclination angle (1° to 11°) and version angle (4° to 18°). The version angle was typically retroverted in comparison to the implantation position (greatest devi-ation 27o). This orientation is substantially different to the static, 0° version simplifying assump-tions in pre-clinical ‘edge loading’ testing. For aim 2, the cup orientation angles were compared between the fast and slow walking groups using statistical parametric mapping. The only signifi-cant differences observed were for cup version angle, for ~12% of the gait cycle, before toe-off (p < 0.05). Therefore, self-selected walking speed, in isolation, is not a sufficient proxy measure for dynamic acetabular orientation. For aim 3, correlations were recorded between the acetabular cup orientation angles and the planar pelvic angles. The cup inclination angle during gait was strongly correlated (Spearman’s coefficient -1) with pelvic obliquity alone, indicating that simple planar assessment could be used to anticipate range of inclination angle. The cup version angle was cor-related with both pelvic rotation and tilt (Spearman’s coefficient 0.8-1), indicating that cup version cannot be predicted directly from any single pelvic movement. This complexity, along with the interaction between inclination angle and range of version angle, supports the use of computa-tional tools to aid clinical understanding

Fruit and Vegetable Intake, Food Security, Barriers to Healthy Eating, and Empowerment Among Dietetic Interns and Physician Assistant Interns: A Cross-Sectional Pilot Study

Students are required to complete supervised practice hours prior to becoming Registered Dietitians and Physician Assistants. Research suggests that environmental and social factors affect dietetic interns’ diets during their internship, although these factors have not been studied among physician assistant interns. This cross-sectional study utilized an online survey to compare dietetic interns’ (n = 81) and physician assistant interns’ (n = 79) fruit and vegetable intake, food security, barriers to healthy eating, and empowerment for making healthy dietary choices during an internship. Differences were assessed via independent t-tests and chi-square distributions. The significance was set at p \u3c 0.05. Dietetic interns had a higher vegetable intake (p = 0.002) while physician assistant interns had higher rates of food insecurity (p = 0.040). Dietetic interns reported a greater impact on their dietary choices due to mental fatigue (p = 0.006), while physician assistant interns’ dietary choices were more heavily impacted by peer influence, interactions with patients, and interactions with preceptors (p \u3c 0.05). There was not a group difference in overall empowerment (p = 0.157), although both groups rated empowerment for asking for help with food and nutrition challenges the lowest of the empowerment sub-items. Addressing interns’ unique needs may support students’ educational success and wellbeing once they are professionals, promote a diverse workforce, and ensure optimal care for patients