Medial-lateral loading and wear in TKA

Pre-clinical wear testing of Total Knee Arthroplasty has traditionally been carried out in a physical experiment [Fisher, 2002]. Recent computational models have been shown to have sufficient accuracy to be considered alongside these experiments [Knight, 2007]. These computational models use a relationship of wear volume proportional to the product of contact pressure, sliding distance and cross shear [Maxian, 1996]. Instrumented knees have recently shown that medial-lateral (ML) loads may be of similar magnitudes to that of the anterior-posterior (AP) load. The AP load is known to have a significant effect on the kinematics of the total knee replacement and so it is reasonable to assume that application of an ML load may have a similar degree of influence on kinematics. The effect of the ML load is hypothesised to increase the cross shear and hence the wear rate. At present, the ISO standard for testing TKA contains no provision for a ML load

Deep Predictive Models for Collision Risk Assessment in Autonomous Driving

In this paper, we investigate a predictive approach for collision risk assessment in autonomous and assisted driving. A deep predictive model is trained to anticipate imminent accidents from traditional video streams. In particular, the model learns to identify cues in RGB images that are predictive of hazardous upcoming situations. In contrast to previous work, our approach incorporates (a) temporal information during decision making, (b) multi-modal information about the environment, as well as the proprioceptive state and steering actions of the controlled vehicle, and (c) information about the uncertainty inherent to the task. To this end, we discuss Deep Predictive Models and present an implementation using a Bayesian Convolutional LSTM. Experiments in a simple simulation environment show that the approach can learn to predict impending accidents with reasonable accuracy, especially when multiple cameras are used as input sources.Comment: 8 pages, 4 figure

Influence of wear algorithm formulation on computational-experimental corroboration

Experimental wear testing is well-established as an important part of the TKR design process. Recently, in-silico models have proved their value to corroborate long-term in-vitro results on a much shorter timescale [1]. Both FE-based models & multi-body dynamics can be used to predict contact pressures, sliding distances and cross-shear (CS). The precise mechanisms of wear are not sufficiently understood to permit analytical calculations, and so empirical formulations are used to estimate wear depths & volumes.Most early simulations were based on a modified Archard/Lancaster formulation; more recently a number of alternative formulations for cross shear have been proposed; it is unclear which is the most robust or accurate for the widest range of activities. The aim of this study was to develop and corroborate a fast in-silico wear model, and use this to compare different wear formulations

System integration office project missile system evaluation

Issued as Monthly technical reports no. [1-8], Project A-347

Contemporary American craft and industrial unionism in theory and practice.

Thesis (M.A.)--Boston Universit

Muscle activation patterns in shoulder impingement patients

Introduction: Shoulder impingement is one of the most common presentations of shoulder joint problems 1. It appears to be caused by a reduction in the sub-acromial space as the humerus abducts between 60o -120o – the 'painful arc'. Structures between the humeral head and the acromion are thus pinched causing pain and further pathology 2. Shoulder muscle activity can influence this joint space but it is unclear whether this is a cause or effect in impingement patients. This study aimed to observe muscle activation patterns in normal and impingement shoulder patients and determine if there were any significant differences. Method: 19 adult subjects were asked to perform shoulder abduction in their symptomatic arm and non-symptomatic. 10 of these subjects (age 47.9 ± 11.2) were screened for shoulder impingement, and 9 subjects (age 38.9 ± 14.3) had no history of shoulder pathology. Surface EMG was used to collect data for 6 shoulder muscles (Upper, middle and lower trapezius, serratus anterior, infraspinatus, middle deltoids) which was then filtered and fully rectified. Subjects performed 3 smooth unilateral abduction movements at a cadence of 16 beats of a metronome set at 60bpm, and the mean of their results was recorded. T-tests were used to indicate any statistical significance in the data sets. Significance was set at P<0.05. Results: There was a significant difference in muscle activation with serratus anterior in particular showing a very low level of activation throughout the range when compared to normal shoulder activation patterns (<30%). Middle deltoid recruitment was significantly reduced between 60-90o in the impingement group (30:58%).Trends were noted in other muscles with upper trapezius and infraspinatus activating more rapidly and erratically (63:25%; 60:27% respectively), and lower trapezius with less recruitment (13:30%) in the patient group, although these did not quite reach significance. Conclusion: There appears to be some interesting alterations in muscle recruitment patterns in impingement shoulder patients when compared against their own unaffected shoulders and the control group. In particular changes in scapula control (serratus anterior and trapezius) and lateral rotation (infraspinatus), which have direct influence on the sub-acromial space, should be noted. It is still not clear whether these alterations are causative or reactionary, but this finding gives a clear indication to the importance of addressing muscle reeducation as part of a rehabilitation programme in shoulder impingement patients

Exploration of an on-site pharmacist intervention within Australian residential aged care facilities using normalisation process theory: A mixed-methods study

Residents living in residential aged care facilities (RACFs) continue to experience medication-related harm. There is ongoing interest in expanding the role of pharmacists, including on-site pharmacists (OSPs), to help improve medication management in RACFs. The objectives of this mixed-methods study were to explore the extent and ways in which on-site pharmacists (OSPs) were normalised within RACFs as part of a complex intervention seeking to improve medication management. This study consisted of semistructured interviews informed by normalisation process theory (NPT) and a quantitative survey adapted from the normalisation measure development questionnaire (NoMAD) instrument which is underpinned by NPT. Semistructured interviews with prescribers, RACF managers, RACF nursing staff, OSPs, residents, and family members (n = 47) indicated that most participants supported OSPs within RACFs that having OSPs in RACFs made sense and was perceived as beneficial and that participants were invested in working with OSPs who often became part of routine practice, i.e., “normalised.” Prescribers, RACF managers, and nursing staff (health care team members) completed the adapted survey, and their responses (n = 16) strongly complemented the positive qualitative findings. Overall, OSPs were positively appraised by health care team members as well as residents and family members and were generally considered to be normalised within their respective RACFs. This study explored the normalisation of OSPs within RACFs. From the perspective of residents, family members, health care team members, and OSPs, OSPs could become part of routine practice within Australian RACFs. The findings of this study also highlighted the value of using theory to guide the evaluation of a pharmacist intervention in RACFs and the utility of applying NPT in a new setting, Australian RACFs. Importantly, the findings of this study could help inform the future role of OSPs working and the rollout of OSPs within Australian RACFs