Vol spatial | EPFL Graph Search

Le vol spatial est le mouvement d'un astronef dans et à travers l'espace. Le vol spatial est utilisé dans le cadre de l'exploration spatiale, et dans les activités commerciales liées telles que le tourisme spatial et les satellites de télécommunication. D'autres usages non commerciaux sont également recensés, tels que les télescopes spatiaux et les satellites espions ou ceux d'observation de la planète. Un vol spatial débute par un lancement, procurant la poussée initiale permettant d'outrepasser la force de gravitation et d'arracher le vaisseau de la surface terrestre. Une fois dans l'espace, le mouvement du vaisseau, qu'il soit propulsé ou non, est déterminé par les lois de la mécanique spatiale. Certains engins spatiaux restent dans l'espace indéfiniment, certains se désintègrent pendant leur rentrée atmosphérique et d'autres atteignent la surface pour un atterrissage ou un impact. Histoire Histoire du vol spatial La première proposition théorique de voyage spatial à

Evaluation and robotic simulation of the glenohumeral joint

Matteo Mancuso

The shoulder is the joint with the largest range of motion in the human body. It is composed of three articulations, the glenohumeral articulation providing about two thirds of its mobility which is, also the most complex and fragile of the three. For this reason, it possesses a particularly complex stabilization mechanism involving a large number of different structures, making it particularly difficult to model, evaluate and treat. Since many structures are involved in the stabilization of this articulation, pathologies affecting any of these elements may compromise the whole stabilization mechanism. In that case, a good understanding of the mechanisms involved, combined with reliable evaluation tools are necessary to provide an effective treatment. At present, different modelling approaches tried to model the phenomenon of glenohumeral instability, but none was able to replicate the whole mechanism reliably. These limitations are particularly problematic during total shoulder replacement surgeries, where the inability to reproduce healthy glenohumeral motions is the main cause of implant failure. The development of a model able to predict the onset of GH instability based on the surgical planning, would greatly improve the general survivor-ship of the implants, and is one of the main goals of this thesis. Additionally, the clinical tools available for the evaluation of the functional outcome are limited. Clinical questionnaires, static apprehension and laxity scores and two-dimensional evaluations of the articular ranges being the instruments used in most situations. Although fast and simple, these instruments are either prone to biases based on patients' interpretation and psychological state or provide only a partial evaluation of the functional limitations. Considering that the main function of the upper limb (composed of the shoulder, arm, elbow and forearm) is to place and orient the hand in space, for the latter to perform a particular action; the reachable space defined as the total volume where the upper limb is able to place the hand, is a feature of great interest. In biomechanical research laboratories, measurements with standard motion capture system enables a more comprehensive and accurate evaluation of the whole upper limb, including the evaluation of its reachable space. Unfortunately, the use of such platforms is generally too complex, expensive and time-consuming for clinical examinations. To this end, the development of new tools able to bring some of the most interesting features recorded in biomechanical laboratories to the clinical context would offer promising new solutions for the functional evaluation of patients and represent the second goal of this thesis. This thesis proposes two original instruments for the evaluation and robotic simulation of the glenohumeral joint. It offers a tool for reproducing physiological forces and motions within the glenohumeral joint, opening new opportunities for the study of glenohumeral instability. At the same time, it also proposes a second instrument allowing to evaluate the functional impairment of a patient's upper limb in an objective and reliable way, extracting information that in the past required the deployment of unrealistic amounts of resources for a clinical examination.

EPFL2020

Atomic Force Microscopy of Biological Systems: Quantitative Imaging and Nanomotion Detection

Petar Stupar

The core of this thesis is the application of different modalities of atomic force microscopy to study living systems. After a brief introduction, quantitative imaging state of the art is presented and the applications for mammalian, plant, bacterial, and yeast cells are reviewed. The same chapter contains research effort about exploring nanomechanical properties of bone cells exposed to conditions that simulate the ones in outer space, in order to investigate the changes in architectural rearrangements of cells during space flight. The next section takes the focus on probing bacterial adhesion sites with an antibody-modified tip, a research important for the understanding of how bacterial cells adhere to the host and establish an infection. Plant cells and their nanomechanical profiles are also covered in the chapter. A large portion of the thesis consists in development of a new nanomechanical sensing technique, and the exploration of its potential applications. The technique is based on the AFM detection method and focuses on transducing small fluctuations that define living systems into a measurable mechanical change in the cantilever. The fact that there is a disproportionate rise in antimicrobial-resistant bacteria and that our lives depend on the new drugs and diagnostic tools to fight them has fueled the first and largest application of the technique â rapid antimicrobial susceptibility resting. Chapter 3 starts with the introduction of the technique, basic principles and guidelines for its use, and continues on potential applications. Proof of principle of the technique is presented, showing experimental results using blind clinical samples of bloodstream infectious agents. A separate section is devoted to investigations concerning slow-growing bacteria and the application of the technique to rapidly determine which antibiotic would best work against them. It then expands on the applications towards detecting metabolic activity of mitochondria and their response to substrates and inhibition. Furthermore, the method has been described as a rapid anti-cancer profiling tool that might pave the way towards a diagnostic platform for personalized medical treatment. The final section of the third chapter contains the current knowledge of the origins of oscillatory movement that governs the nanomotion technique. It presents different hypothesis and results towards exploring them. The thesis ends with a summary of the main ideas and conclusions about the presented work and future perspectives.

EPFL2018

Evaluation and robotic simulation of the glenohumeral joint

Matteo Mancuso

EPFL2020

Atomic Force Microscopy of Biological Systems: Quantitative Imaging and Nanomotion Detection

Petar Stupar

EPFL2018