The purpose of this study is to create an accurate experimental database for the passive (in vitro)freedom-of-motion characteristics of the human knee joint on a subject to subject basis, suitable for the verification and enhancement of mathematical knee-joint models. Knee-joint specimens in a six degree-of-freedom motion rig are moved through flexion under several combinations of external loads, including tibial torques, axial forces and AP-forces. Euler rotation angles and translation vectors, describing the relative, spatial motions of the joint are measured using an accurate Roentgen Stereo Photogrammetric system. Conceptually the joint is considered as a two degrees-of-freedom of motion mechanism (flexion-tibial rotation), whereby the limits of internal and external tibial rotation are defined at torques of ± 3 Nm. The motion pathways along these limits are denned as the envelopes of passive knee joint motion. It is found that these envelope pathways are consistent and hardly influenced by additional axial forces up to 300 N and AP-forces of 30 N. Within the envelope of motion, however, the motion patterns are highly susceptible to small changes in the external load configuration. It is shown that the external tibial rotation during extension ('screw-home mechanism') is not an obligatory effect of the passive joint characteristics, but a direct result of the external loads. Anatomical differences notwithstanding, the inter-individual discrepancies in the motion patterns of the four specimens tested, showed to be relatively small in a qualitative sense. Quantitative differences can be explained by small differences in the alignment of the coordinate systems relative to the joint anatomy and by differences in rotatory laxity.
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AbstractIn many biomechanical motion studies, kinematic parameters are estimated from position measurements on a number of landmarks. In the present investigation, dummy motion experiments are performed in order to study the error dependence of kinematic parameters on geometric factors (number of markers, isotropic vs anisotropic landmark distributions, landmark distribution size), on kinematic factors (rotation step magnitude, the presence of translational displacements, the distance of the landmarks' mean position to the rotation axis), and on anisotropically distributed measurement errors. The experimental results are compared with theoretical predictions of a previous error analysis assuming isotropic conditions for the measurement errors and for the spatial landmark distribution. In general, the experimental findings agree with the predictions of the error model. The kinematic parameters such as translations and rotations are well-determined by the model. In the helical motion description, the same applies for the finite rotation angle about and the finite shift along the helical axis. However, the direction and position of the helical axis are ill-determined. An anisotropic landmark distribution with relatively few markers located in the direction of the rotation axis will even aggravate the ill-posed nature of the finite helical axis estimation.
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INTRODUCTION: The aim of this study was to determine the degree of ROM limitations of extremities, joints and planes of motion after burns and its prevalence over time.METHOD: The database of a longitudinal multicenter cohort study in the Netherlands (2011-2012) was used. From patients with acute burns involving the neck, shoulder, elbow, wrist, hip, knee and ankle joints that had surgery, ROM of 17 planes of motion was assessed by goniometry at 3, 6 weeks, 3-6-9 and 12 months after burns and at discharge.RESULTS: At 12 months after injury, 12 out of 17 planes of motion demonstrated persistent joint limitations. The five unlimited planes of motion were all of the lower extremity. The most severely limited joints at 12 months were the neck, ankle, wrist and shoulder. The lower extremity was more severely limited in the early phase of recovery whereas at 12 months the upper extremity was more severely limited.CONCLUSION: The degree of ROM limitations and prevalence varied over time between extremities, joints and planes of motion. This study showed which joints and planes of motion should be watched specifically concerning the development of scar contracture.
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The anterior cruciate ligament (ACL) is a strong rope-like tissue which connects the femur to the tibia in the knee joint. Its function is to provide structural stability to the knee while preventing unnatural forward movement of the tibia relative to the femur. Acute complete ACL ruptures during movements like knee hyperextension or sudden changes of direction (pivoting) damage two entities: the ligament itself and its nerve connections to the posterior tibial nerve (PTN). PTN innervation in the ACL is essential for: a) proprioception (e.g. perception of position and movement/acceleration experienced by the ligament), and b) stability of the knee joint. Upon ACL rupture, the orthopedic surgeon reconstructs the ACL with a graft from the hamstring, patellar or quadriceps tendon. After the surgery, the goal is to regain neuromuscular control and dynamic stabilization during rehabilitation as soon as possible for a quick return to sports and daily activities. However, surgeons are not able to reconstruct the nerve gap between the PTN and the grafted ligament due to the microscopic size of the innervation in the ACL. Not linking the PTN to the graft creates a disconnection between the knee joint and the spinal cord. To mitigate these disadvantages in ACL surgery, this study focuses on activating the growth of proprioception nerve endings using a ligament loaded with growth factors (neurotrophins). We hypothesize that neurotrophins will activate proprioceptive fibers of neurons close to the ACL. We describe graft fabrication steps and in vitro experiments to expand on the regeneration capacity of a commercially available ACL-like synthetic ligament called LARS. The results will bring the ACL regeneration field closer to having a graft that can aid patients in regaining mobility and stability during locomotion and running, confidence in the strength of the knee joint, and quick return to sports.
Cell-based production processes in bioreactors and fermenters need to be carefully monitored due to the complexity of the biological systems and the growth processes of the cells. Critical parameters are identified and monitored over time to guarantee product quality and consistency and to minimize over-processing and batch rejections. Sensors are already available for monitoring parameters such as temperature, glucose, pH, and CO2, but not yet for low-concentration substances like proteins and nucleic acids (DNA). An interesting critical parameter to monitor is host cell DNA (HCD), as it is considered an impurity in the final product (downstream process) and its concentration indicates the cell status (upstream process). The Molecular Biosensing group at the Eindhoven University of Technology and Helia Biomonitoring are developing a sensor for continuous biomarker monitoring, based on Biosensing by Particle Motion. With this consortium, we want to explore whether the sensor is suitable for the continuous measurement of HCD. Therefore, we need to set-up a joint laboratory infrastructure to develop HCD assays. Knowledge of how cells respond to environmental changes and how this is reflected in the DNA concentration profile in the cell medium needs to be explored. This KIEM study will enable us to set the first steps towards continuous HCD sensing from cell culture conditions controlling cell production processes. It eventually generates input for machine learning to be able to automate processes in bioreactors and fermenters e.g. for the production of biopharmaceuticals. The project entails collaboration with new partners and will set a strong basis for subsequent research projects leading to scientific and economic growth, and will also contribute to the human capital agenda.
This project aims to develop a measurement tool to assess the inclusivity of experiences for people with varying challenges and capabilities on the auditory spectrum. In doing so, we performed an in-depth exploration of scientific literature and findings from previous projects by Joint Projects. Based on this, we developed an initial conceptual model that focuses on sensory perception, emotion, cognition, and e[ort in relation to hearing and fatigue. Within, this model a visitor attraction is seen as an “experienscape” with four key elements: content, medium, context, and individual. In co-creative interviews with experts by experience with varying challenges on the auditory spectrum, they provided valuable insights that led to a significant expansion of this initial model. This was a relevant step, as in the scientific and professional literature, little is known about the leisure experiences of people with troubled hearing. For example, personal factors such as a person’s attitude toward their own hearing loss and the social dynamics within their group turned out to greatly influence the experience. The revised model was then applied in a case study at Apenheul, focusing on studying differences in experience of their gorilla presentation amongst people with varying challenges on the auditory spectrum.Societal issueThe Netherlands is one of the countries in Europe with the highest density of visitor attractions. Despite this abundance, many visitor attractions are not fully accessible to everyone, particularly to visitors with disabilities who sometimes are not eligible to ride due to safety concerns, yet when eligible generally still encounter numerous barriers. Accessibility of visitor attractions can be approached in various ways. However, because the focus often lies on operational and technical aspects (e.g., reducing stimuli at certain times of the day by turning o[ music, o[ering alternative wheelchair entrances), strategic and community-focused approaches are often overlooked. More importantly, there is also a lack of attention to the experience of visitors with disabilities. This becomes apparent from several studies from Joint Projects, where visitor attractions are being visited together with experts by experience with various disabilities. Nevertheless, experience is often being regarded as the 'core product' of the leisure sector. The right to meet, discover, develop, relax and thus enjoy this core product is hindered for many people with disabilities due to a lack of knowledge, inaccessibility (physical, digital, social, communicative as well as financial) and discrimination in society. Additionally, recreation entrepreneurs still face a significant gap in reaching the potential market of guests with disabilities and their networks. Thus, despite the numerous initiatives in the leisure sector aimed at improving accessibility on technical and operational fronts, often people with disabilities are still not being able to experience the same kind of enjoyment as those without. These observations form the pressing impetus for initiating the current research project, tapping into the numerous opportunities for learning, development and growth on making leisure offer more inclusive.Benefit to societyIn total, the current project approach comes with a number of enrichments in terms of both knowledge and methodology: a mixed-methods approach that allows for comparing data from different sources to obtain a more complete picture of the experience; a methodological co-design process that honours the 'nothing about us without us' principle; and benchmarking for a group (i.e., people with challenges on the auditory spectrum) that despite the size of its population has thus far mostly been overlooked.
