CONSERVATION OF HERITAGE MASONRY IN CANADA: A CURRENT PERSPECTIVE

Canada is a young country with respect to its built heritage. The need to conserve examples of its structures as a record of the history of settlement and growth has been recognized for some time by the somewhat small conservation community. The heritage conservation sector is growing compared to new construction. Unfortunately, there is a distinct lack of professional expertise (architects and engineers) familiar with the older traditional construction materials and methods, leading to some recommendations with respect to heritage structures being inconsistent with conservation principles. There is even less knowledge with respect to understanding how modern interventions will affect the construction supposedly being conserved. There is therefore a need for education in conservation principles and methodology. Two new programs are described, one at the undergraduate level at Carleton University, and the other at the graduate level at the University of Calgary. Both of these programs are being developed with advice from the Heritage Conservation Directorate of Public Works and Government Services Canada. The potentially negative consequences of the current lack of expertise for heritage structures are compounded by the current system for deciding whether or not a structure has heritage value. The system is inconsistent across the country, depending on how the guidelines interpreted and enforced. The federal and provincial and some municipal governments have collaborated in establishing guidelines for their areas of responsibility, but there is no overarching regulation for the protection of heritage across the country

The Effect of Tube Wall Stiffness on the Speed of Waves in Tubes

The heart creates pulsatile flow in the arterial and pulmonary circulations. The vessels that make up these systems are distensible, so part of each pulse of blood fills the increasing volume of these vessels, while the remaining blood continues to flow down the vessel. Once the pulse has passed, and the valves from the heart are closed, the vessels contract under their own elasticity, pushing the “stored” blood further down the system. Thus the flow at the beginning of the aorta varies differently over time to flow further down that vessel. Different vessels in each circulatory system appear to have different wall thicknesses and stiffnesses. Further, some organs like the kidney and the brain would appear to function better under continuous blood flow rather than pulsatile flow. Thus we are interested in how wall stiffness of the vessels affects how much blood is “stored” from each pulse and then pushed on down the system, and how the velocity of the wave is affected by wall stiffness. We wish to understand how the body does supply more uniform flow to some organs than to other parts of the circulation. The distensibility of seven tubes with different wall stiffness and thickness was measured. Meter lengths of the three tubes most sensitive to pressure change were attached to a pump that delivered a pulsatile waveform resembling aortic flow. The flowrate and pressure changes were measured in the proximal and distal part of each tube. The distensibility of each tube was calculated again and found to be slightly larger than in the first experiment, possibly due to the non-steady state situation. As expected, the more stiff the tube the less the volume that can be stored. Of interest are the rate of reduction in storage with wall stiffness, and the rate of change in wave speed

DOES IN VIVO LIGAMENT FORCE PASS THROUGH LIGAMENT INSERTIONS?: A ROBOTIC STUDY

INTRODUCTION Post traumatic osteoarthritis (PTOA) is a subset of osteoarthritis that arises after traumatic joint injury. Approximately half of patients suffering from anterior cruciate ligament (ACL) injuries have been shown to progress towards PTOA within fifteen years[1]. One of the areas of research for PTOA is examining the biomechanical changes following an ACL injury. A recent study[2] examined the effects of ACL transection (ACLx) in an ovine model. In vivo stifle joint motions were recorded, and recreated in vitro using a novel robotic testing platform. Joint and tissue loads were simultaneously recorded during reproduction of in vivo joint motion[2]. This novel approach was shown to be able to reproduce in vivo motions within less than 0.1° and 0.1mm[2].   The main objective of the present study was to determine if in vivo ligament forces, obtained using the principle of superposition, pass through respective ligament insertional footprints. This study evaluated the accuracy of the measured ligament forces, as they should pass through their bony insertions. This accuracy was examined for medial and lateral collateral ligaments (MCL and LCL), and posterior cruciate ligament (PCL) in ACLx sheep.   METHODS Stifle joints from N=4 sheep that had been previously examined in ACLx kinematics studies were digitized using a coordinate measuring machine. The ligament insertional areas were thoroughly recreated in 3D space, along with the spatial position of the kinematic measurement device. Anatomic coordinate systems were defined on the femur and the tibia. These data were then exported to MATLAB scripts for further analysis. The ligament insertional areas were approximated as planes using least squares regression technique. The intersection of the ligament force vectors with the plane approximations were then calculated. The direction of a ligament force was deemed accurate if the distance between the calculated intersection and footprint centroid was within a determined threshold. A preliminary threshold was calculated as the maximum distance between the centroid and measured points of the footprint. RESULTS Analysis of the data indicated that the technique increases in accuracy for high ligament loads (Figure 1). That is to say as the ligament loads increase, the intersection-centroid distance is reduced. For lower ligament loads (mainly within the “toe” region of the ligament force-displacement behavior), however, the method requires further refinement. DISCUSSION AND CONCLUSIONS This study indicated that the method requires further refinement based on the limitations induced currently. Preliminary data shows that accuracy increases as ligament load magnitudes increase as well. Finding the intersections on plane approximations of the insertional footprints can lead to very large error when the planes approach a parallel state. In these states, a small angular change in force direction can cause a very large change in intersection-centroid distance. Each ligament and its insertions have different functions and geometries, and as such require separate limitations. Future studies would require modifications to the analysis method to account for the limitations involved with the current method

The why, how and when of LGBT+ education in primary schools in England.

This study aims to contribute to the field of primary education and inclusive practices by discussing when and how lesbian, gay, bisexual, transgender plus (LGBT+) education is being taught and what primary school teachers need to feel confident in teaching LGBT+ content.Despite changes in the English National Curriculum, the LGBT+ community and associated laws in the UK, it is still not compulsory for LGBT+ content to be taught in English primary schools. This can cause conflict for school leaders and teachers in deciding how and when to teach LGBT+ education and an inconsistent approach regarding LGBT+ content and teaching (DfE, 2019a, p.15; Glazzard and Stones, 2020, p.2). This discordance raises issues regarding what should and should not be taught in primary schools, from the perspectives of both teachers and parents; the matter of an LGBT+ inclusive curriculum is becoming a controversial topic.This poster will explore the year group in which teachers feel LGBT+ education should first be taught, the areas that impact teachers’ confidence, and the most effective strategies that can be used to deliver content. This study employed an online survey of primary school teachers in England and semi structured interviews to evaluate the overarching question of why, how, and when LGBT+ content could be taught in primary schools.Methodology, Methods, Research Instruments or Sources UsedThis study used an online questionnaire given to all participants via opportunity sampling, in this case – 58 primary school teachers from a range of schools across England and years Reception through to Year 6. Due to the nature of the research, participants were asked to disclose their gender identities and sexualities so that it could be identified whether this influenced their responses. From this, it was identified that twenty-six percent of participants identified as a sexuality that was not heterosexual, and two percent of participants did not identify as the gender they were assigned with at birth. To also allow for more interpretivist responses, one-to-one semi structured interviews were used (n=3). These participants were of a range of ages, worked in different year groups and all identified differently by gender and sexuality. Interviews were transcribed and a process of inductive coding was used, which involved categorising the data into different themes or labels so that patterns can be identified, examined and discussed (Cohen et al., 2018, p.645). The same approach was used to code the qualitative data from the open questionnaire questions (Figure 1). Ethical guidance from BERA (2018) was used and ethical approval given by the University of Northampton and considered aspects such as consent, withdrawal, confidentiality and the safe storage of data (Cohen et al., 2018, p.111). As well as these key ethical considerations, several other ethical aspects were important due to the nature of the topic, such as the sensitivity of the topic, limiting bias alongside actions to be taken in the case of ethical dilemmas.Conclusions, Expected Outcomes or FindingsThis study intended to explore why, how, and when to deliver LGBT+ education in English primary schools but the is much to contribute to wider LGBT+ education and awareness more widely. Most teachers feel LGBT+ content should be taught at some point within primary education, and most of these feel that it should begin being taught from Reception or Year 1 as this cultivates an environment of respect and acceptance. When considering strategies to deliver LGBT+ content, this study identified that teachers’ feel PSHE lessons or circle time are the most effective strategies to deliver LGBT+ content, however teachers would appreciate a specific scheme of work to support them in delivering this. Furthermore, participants expressed that use of literature and integration of LGBT+ content across the curriculum are also effective strategies as this normalises LGBT+ topics. Half of participants felt confident in teaching LGBT+ content, however, many teachers still felt they need to grow in confidence; the lack of training and resources and a fear of parental opposition being the key factors that concern them (DePalma, 2018, p.9; Barnes and Carlile, 2018, p.33). There is a need for resources to be developed to allow teachers and trainee teachers to build their confidence in teaching age-appropriate activities. Initial teacher training can begin this process by considering the broadness of opportunity to be inclusive and looking for opportunities to build LGBT+ content into their curriculums. Training providers should work closely with school-based mentors to allow trainee teachers the opportunity to experience how content is taught and the culture of the school can be representative of a range of communities

Analyzing Strain in the Ovine Anterior Cruciate Ligament

Osteoarthritis (OA) is the most common joint disorder affecting adults. Relating the mechanics and biology of the knee joint is crucial to understanding the development and progression OA. A key aim of such studies is to determine the structure/function relationship and failure thresholds of the joint tissues, in-vivo. The Anterior Cruciate Ligament (ACL) is of great interest as it is one of the most commonly injured ligaments linked with premature OA. Previous ACL studies have been unable to determine the stresses within the structure, due to absence of reliable methods of measuring the cross-sectional area of the loaded part of the ligament. Purpose: This study aims to evaluate the normal in-vivo stresses within the ACL, by developing a suitable method to measure the loaded area of the ACL. Methods: Ovine stifle joints were used due to morphological and biochemical proximity to human knee joints. Measurements of in-vivo loadings within the ACL were obtained using an instrumented spatial linkage and robotic test system. Two techniques to measure the area of the loaded ACL will be explored: 3D Virtual Reconstruction (3DVR) and Magnetic Resonance Imaging (MRI). 3DVR: The non-loaded part of the ACL was removed. A cloud of points was measured along the surface of the remaining (loaded) part of the ligament and processed to create a 3DVR of the ACL. MRI: Tests (proton density and T2 mapping) will be run on the 9.4T MR to compare structural differences between a loaded and relaxed ligament. Results: 3DVR method produced only a partial surface reconstruction due to the relatively large size of the probe in comparison to the ligament and femorotibial joint space. Differences between loaded and unloaded MRI images will be assessed using a special jig allowing sequential tensioning of the ligament. Conclusions: It was concluded that the partial 3DVR was insufficient to determine the loaded cross- sectional areas along the ligament accurately. The MRI results will be available for examination shortly

DEVELOPMENT OF A LOADING DEVICE FOR IMAGING RABBIT MCL ENTHESES WITH SECOND HARMONIC GENERATION MICROSCOPY

INTRODUCTION Entheses are transitional structures in the body between a flexible material and a much stiffer material: ligament and bone, respectively. A gradual transition of mineral content and collagen fibre organization enables the enthesis to dissipate stress concentrations and transfer load between the adjoining elements, contributing to normal joint function [1]. Damage to this small region is associated with conditions like tennis elbow and jumper’s knee. Enthesis tears do not repair well, causing long term weakness. To date, the challenge of observing entheses under applied load has inhibited understanding of their mechanical behaviour. Second Harmonic Generation (SHG) microscopy is a technology that can be used to image highly polarizable proteins like collagen without the need for section fixation or molecular excitation [2]. Given that collagen fibre structure affects load transfer at entheses, SHG microscopy is an ideal tool to elucidate the fibre structure at MCL entheses. The purpose of the project described was to develop a custom device to allow observation of the collagen fibre network of the rabbit medial collateral ligament (MCL) enthesis in the SHG microscope as tensile load is applied. METHODS After generating a morphological chart of alternative solutions, the optimal option was chosen based on project requirements. The design was created with CAD software (SolidWorks 2015) and where possible, the proposed design was modified to optimize objectives— minimizing cost and maximizing movement accuracy. With CAD, it is easy to modify components of a model while assessing its impact on the model as a whole. RESULTS In the final design, the rabbit bones can be secured to bone pots at a physiological angle of 70°, with the MCL in the line of action of the applied force. One bone pot remains stationary as the other, sliding on rail guides which constrain pot movement, is pulled by a linear actuator. A custom load cell will collect force data as the load is applied. For its light-weight property and potential to be scanned using MRI, Perspex is the material of choice for the device. The completed design, shown in Figure 1, satisfies all the requirements previously established and requires only one hand for operation. This model allows for a testing procedure simulating physiological conditions while maximizing accuracy of the recorded data through incorporating rail guides and making use of a linear actuator. DISCUSSION AND CONCLUSIONS With some minor modifications to the bone pots, this device can be used as a reference product for the study of other tissues under load. However, it would be worthwhile to consider interchanging the bone pots between uses since the bone cement is difficult to remove. The small size of entheses has stymied researchers’ efforts to characterize their inhomogeneous material behavior. However, this device will enable the observation of collagen fibre behaviour under load, which will provide insight into mechanisms of load transfer in the enthesis and in time, contribute to improved surgical attachment procedures