Contraception

Résumé

thumb|Pilules contraceptives La contraception est l'emploi de moyens visant à empêcher qu'un rapport sexuel entraîne une grossesse. Elle est définie par l'Organisation mondiale de la santé comme étant « l'utilisation d’agents, de dispositifs, de méthodes ou de procédures pour diminuer la probabilité de fécondation ou l’éviter ». Il existe plusieurs méthodes de contraception, d'action locale ou générale, à l'efficacité et aux contraintes variables. Parmi ces méthodes, le préservatif peut également être utilisé pour la prévention de nombreuses infections sexuellement transmissibles. Plus généralement, la contraception peut s'intégrer dans une stratégie de contrôle des naissances ou de planification familiale, à un niveau individuel ou collectif. La contraception est souvent associée aux femmes, la majorité des solutions proposées (pilule, stérilet...) étant conçues pour elles. Il existe cependant des contraceptions masculines (contraception hormonale, thermique ou chirurgicale) qui

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Level up the interaction space with Cellulo robots

Lucas Burget

Cellulo, as tabletop tangible robots, are a great tool for interactive learning and upper limb rehabilita-tion. For the moment, the main way of interaction is to take them in hand and move them in the plane.Thus, due to the laws of physics, the different gestures induced are mainly constrained to be in 2D andthe workspace is bounded by the length of the arm. More precisely, for upper limb rehabilitation, itlimits the solicitation of certain arm joints, for instance the shoulder absduction/adduction. In orderto overcome these limitations, the idea was to use two wristbands with sensors to consider the armsof the user as a remote control. For the rehabilitation part, this would allow the patient to train thejoints of his arm with greater amplitude. But more generally, this new mean of interaction with theCellulo allows more possibility in the creation of activities.This semester project studied two different aspects: pointing direction and gesture recognition. Thefirst could be used by the game Master to change the behavior of some robots in order to adapt to thesituation. And the second could be destined to control a swarm of robots. The governing principle ofthis semester project was to implement systems as light and easy to use as possible.

2019

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Electrical spinal cord stimulation protocols to regulate neurological functions after spinal cord injury

Salif Axel Komi

Spinal cord injury (SCI) is a life-changing event. People who suffer from it lose their abilityto move normally and are subject to life-threatening symptoms. When the insult is not toosevere, partial recovery is possible. Otherwise, for severely affected people, the perspectives toever retrieve normal functions is almost non-existent. A critically important window to promoteplasticity is in the acute phase after the trauma (weeks to months). However, at this stage,people cannot take active part in rehabilitation programs due to their incapacity to activate theirlimbs and to the apparition of severe autonomic symptoms such as orthostatic hypotension.Hence, current activity-based treatments are of little help for this population. Consequently, SCIdramatically affects their autonomy and quality of life on the life-long term.Continuous Epidural Electrical Stimulation (EES) of the spinal cord has been proposed as amethod to reactivate dormant neural networks innervated below the site of injury. It enablesrobust control over locomotion and autonomic functions. In animal models of severe lesion,continuous EES promoted long lasting recovery of motor abilities when coupled with an intensivetraining. In human, its recent application indeed supported overground walking in chronicallyand severely injured people, but only showed limited plastic effects when compared to animals.Why? Recent advances support that continuous EES abolishes proprioceptive feedback thatis essential to promote recovery. Moreover, late treatment of severe injuries consistently fail apromoting recuperation of functions. Alternatively, over the last decade, our laboratory developeda spatio-temporally patterned approach to EES. In addition to restore fine control over motorfunctions, this technique avoids the caveats of continuous EES, and hypothetically opens a windowof opportunity for plasticity to happen. In this thesis, we propose a translation of this concept tohumans. We first demonstrate that spatio-temporal EES restores robust and versatile locomotorcontrol in people with chronic incomplete, though severe, SCI. Furthermore, the results supportan aptitude of this approach to promote long lasting recovery of functions without stimulationafter 5 months of intensive training. We then report on a patient-tailored technology, thatincludes personalized computational models enabling precise pre-operative planning strategies, anew electrode-lead and control softwares. This technology enables restoration of various motorfunctions in people with chronic and motor-complete injuries within few hours after beginningof therapy. Finally, we transfer this targeted approach to the control of blood pressure. Wedemonstrate that closed-loop stimulation protocols support a precise control over arterial bloodpressure in rodents, non-humane primates and humans with severe SCI submitted to challengingcardiovascular conditions. Combined, the results presented in this manuscript open a clinicallyrealistic perspective for the application of EES acutely after injury and to potentially promoterobust recovery in severe SCI.

EPFL2021

Chargement

In the framework of this thesis self-assembled supramolecular architectures of several molecular species on crystal metal surfaces are characterized. These investigations combine results obtained by means of scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), X-Ray Photoelectron Spectroscopy (XPS), and Near-Edge X-Ray Absorption Fine Structure Spectroscopy (NEXAFS). The interest in controlling the formation of specific arrangements of supramolecular ensembles at surfaces is motivated to a great extent by the prospect to design molecular devices and nanomaterials with customized properties. The goal is a "spontaneous" creation of targeted, well-ordered molecular architectures, which shall be achieved by taking advantage of the molecule's propensity to self-assemble. Control means, in this context, predictability. This term address the accuracy of the prediction of the structures resulting from molecular self-assembly for systems exhibiting different characteristics. Here, system stands for a particular combination of a single-crystal surface and adsorbed molecular species. In a first part, the focus is given to the impact of a Pd(111) surface exhibiting high chemical activity. Due to surface induced deprotonation two resulting chemical states are found for the adsorbed terephthalic acid species. Deprotonation of the carboxyl moieties is observed to affect the topology of the molecular assemblies even though hydrogen bonds (H-bonds) are responsible for the stabilization of assemblies of both, intact and deprotonated molecular species. Therefore, the selective fabrication of a single specific molecular structure becomes a challenge when the surface is prone to induce chemical reactions. Secondly, a molecular species exhibiting conformational flexibility is studied on a largely inert Au(111) surface. It is observed that the characteristic conformational flexibility is also active on the surface, and the molecule is found to adopt different conformations depending on the locally most favorable bonding motif. In particular, phenyl groups may undergo a rotation such that one-dimensional chains can be stabilized by means of intermolecular H-bonds. This phenomenon is very interesting from an adsorbate-substrate interaction point of view, but it limits the predictability of supramolecular structures formed upon self-assembly. In a third step, a comparative study of the self-assembly of three closely related molecular species highlights the impact of concurrent competing intermolecular interactions. Molecules exhibiting an increasing number of possible interaction channels are found to assemble into an increasing number of distinct supramolecular architectures. The most flexible molecular species allowing for different hydrogen-bonding patterns as well as dipolar coupling self-assembles into various structurally complex architectures. Structural predictability, however, is low since the formation of one or the other assembly appears to depend on small variations in sample preparation conditions and on poorly controllable local surface properties. Finally, a system where the resulting structures fully agree with predictions evidences the possibility to control the formation of targeted specific supramolecular architectures. The formation of well ordered bimolecular ribbons and wires over extended length scales is accomplished by the rational choice of both, complementary building blocks for the selective formation of three-fold H-bonds and a nanostructured surface to guide the molecular self-assembly. Furthermore, the impact of H-bond formation on the electronic structure of self-assembled molecular building blocks is probed by STS measurements. The experimental data reveal shifts in the electronic levels depending on the H-bond configuration and on the local characteristics of the underlying surface. In order to improve the precision of such a study, single molecules, homo- and heteromolecular dimers as well as trimers are successfully isolated and assembled by molecular manipulation with the STM tip. Further STS studies on such artificially assembled structures are suggested.

EPFL2008

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EPFL2008

Electrical spinal cord stimulation protocols to regulate neurological functions after spinal cord injury

Salif Axel Komi

EPFL2021