Load on osseointegrated fixation of a transfemoral amputee during a fall: determination of the time and duration of descent

Mitigation of fall-related injuries for populations of transfemoral amputees fitted with a socket or an osseointegrated fixation is challenging. Wearing a protective device fitted within the prosthesis might be a possible solution, provided that issues with automated fall detection and time of deployment of the protective mechanism are solved. The first objective of this study was to give some examples of the times and durations of descent during a real forward fall of a transfemoral amputee that occurred inadvertently while attending a gait measurement session to assess the load applied on the residuum. The second objective was to present five semi-automated methods of detection of the time of descent using the load data. The load was measured directly at 200 Hz using a six-channel transducer. The average time and duration of descent were 242±42 ms [145 ms-310 ms] and 619±42 ms [550 ms -715 ms], respectively. This study demonstrated that the transition between walking and falling was characterised by times of descent that occurred sequentially. The sensitivity and specificity of an automated algorithm might be improved by combining several methods of detection based on the deviation of the loads measured from their own trends and from a template previously established

Performance dispersion for evidence-based classification of stationary throwers

Background: There is a need for better understanding of the dispersion of classification-related variable to develop an evidence-based classification of athletes with a disability participating in stationary throwing events. \ud Objectives: The purposes of this study are (A) to describe tools designed to comprehend and represent the dispersion of the performance between successive classes, and (B) to present this dispersion for the elite male and female stationary shot-putters who participated in Beijing 2008 Paralympic Games. \ud Study design: Retrospective study\ud Methods: This study analysed a total of 479 attempts performed by 114 male and female stationary shot-putters in three F30s (F32-F34) and six F50s (F52-F58) classes during the course of eight events during Beijing 2008 Paralympic Games. Results: The average differences of best performance were 1.46±0.46 m for males between F54 and F58 classes as well as 1.06±1.18 m for females between F55 and F58 classes. The results demonstrated a linear relationship between best performance and classification while revealing two male Gold Medallists in F33 and F52 classes were outliers.\ud Conclusions: This study confirms the benefits of the comparative matrices, performance continuum and dispersion plots to comprehend classification-related variables. The work presented here represents a stepping stone into biomechanical analyses of stationary throwers, particularly on the eve of the London 2012 Paralympic Games where new evidences could be gathered

Dark Matter, Baryogenesis and Neutrino Oscillations from Right Handed Neutrinos

We show that, leaving aside accelerated cosmic expansion, all experimental data in high energy physics that are commonly agreed to require physics beyond the Standard Model can be explained when completing it by three right handed neutrinos that can be searched for using current day experimental techniques. The model that realises this scenario is known as Neutrino Minimal Standard Model (\nu MSM). In this article we give a comprehensive summary of all known constraints in the \nu MSM, along with a pedagogical introduction to the model. We present the first complete quantitative study of the parameter space of the model where no physics beyond the \nu MSM is needed to simultaneously explain neutrino oscillations, dark matter and the baryon asymmetry of the universe. This requires to track the time evolution of left and right handed neutrino abundances from hot big bang initial conditions down to temperatures below the QCD scale. We find that the interplay of resonant amplifications, CP-violating flavour oscillations, scatterings and decays leads to a number of previously unknown constraints on the sterile neutrino properties. We furthermore re-analyse bounds from past collider experiments and big bang nucleosynthesis in the face of recent evidence for a non-zero neutrino mixing angle \theta_{13}. We combine all our results with existing constraints on dark matter properties from astrophysics and cosmology. Our results provide a guideline for future experimental searches for sterile neutrinos. A summary of the constraints on sterile neutrino masses and mixings has appeared in arXiv:1204.3902 [hep-ph]. In this article we provide all details of our calculations and give constraints on other model parameters.Comment: We extended the discussion in several sections, in particular 2, 3 and 8, in response to comments we received after submission of version 1. We added appendix

Biomechanics of transfemoral amputees fitted with osseointegrated fixation: Loading data for evidence-based practice

This presentation will provide an overview of the load applied on the residuum of transfemoral amputees fitted with an osseointegrated fixation during (A) rehabilitation, including static and dynamic load bearing exercises (e.g., rowing, adduction, abduction, squat, cycling, walking with aids), and (B) activities of daily living including standardized activities (e.g., level walking in straight line and around a circle, ascending and descending slopes and stairs) and activities in real world environments. A particular emphasis will be placed on the outcomes of several studies for an evidence-based design of the rehabilitation program and components of the fixation (e.g., implant, abutment). It is anticipated that this work might contribute to the current effort aiming at shortening the rehabilitation program and reducing the incidence of replacement of abutments

Categorisation of activities of daily living of lower limb amputees during short-term use of a portable kinetic recording system: a preliminary study

The purpose of this preliminary study was to determine the relevance of the categorisation of the load regime data to assess the functional output and usage of the prosthesis of lower limb amputees. The objectives were (A) to introduce a categorisation of load regime, (B) to present some descriptors of each activity and (C) to report the results for a case. The load applied on the osseointegrated fixation of one transfemoral amputee was recorded using a portable kinetic system for five hours. The periods of directional locomotion, localised locomotion and stationary loading occurred 44%, 34% and 22% of recording time and each accounted for 51%, 38% and 12% of the duration of the periods of activity, respectively. The absolute maximum force during directional locomotion, localised locomotion and stationary loading was 19%, 15% and 8% of the BW on the antero-posterior axis, 20%, 19% and 12% on the medio-lateral axis as well as 121%, 106% and 99% on the long axis. A total of 2,783 gait cycles were recorded. Approximately 10% more gait cycles and 50% more of the total impulse than conventional analyses were identified. The proposed categorisation and apparatus have the potential to complement conventional instruments, particularly for difficult cases