Syfte Syftet med föreliggande studie var att försöka klargöra om stötvågsbehandling har någon effekt på smärta och handgreppstyrka hos patienter med lateral epikondylalgia. Frågeställningar 1. Har stötvågsbehandling någon effekt på smärta hos patienter med lateral epikondylalgia, i så fall vilken? 2. Har stötvågsbehandling någon effekt på handgreppsstyrka hos patienter med lateral epikondylalgia, i så fall vilken? Metod Sökning av litteratur utfördes i PubMed, Cochrane, Cinahl och PEDro. Detta resulterade i 14 artiklar, som granskades och bedömdes enligt PEDro Scale. Poängbedömningen utifrån PEDro Scale omsattes till Statens Beredning för medicinsk Utrednings (SBU) mall för bevisvärde. Utifrån artiklarnas sammantagna bevisvärde bestämdes evidensnivån enligt SBU:s fyra nivåer. Resultat Enligt GRADE-systemet förelåg det ett starkt vetenskapligt belägg för att stötvågsbehandling har en smärtlindrande effekt vid lateral epikondylalgia. Studier av likartad vetenskaplig kvalitet påvisar motsägande resultat avseende om stötvågsbehandling är bättre än placebo, kortison eller tenotomi. Detta innebär att det vetenskapliga underlaget är otillräckligt och att mer forskning behövs. Enligt GRADE-systemet förelåg det ett starkt vetenskapligt belägg för att stötvågsbehandling leder till förbättrad handgreppsstyrka vid lateral epikondylalgia. Vidare förelåg det ett starkt vetenskapligt belägg för att stötvågsbehandling inte är bättre än någon annan behandling gällande ökning av handgreppsstyrka vid lateral epikondylalgia. Slutsats Stötvågsbehandling har en smärtlindrande effekt hos patienter med lateral epikondylalgia. Det finns dock ingen evidens för att stötvågsbehandling är bättre ur smärthänseende än någon annan behandling såsom placebo, kortison eller tenotomi. Stötvågsbehandling leder till förbättrad handgreppsstyrka men är inte bättre än placebo, kortison eller tenotomi på att öka handgreppsstyrkan hos patienter med lateral epikondylalgia. / Aim The aim of the present study was to try to find out whether shock wave therapy has any effect on pain and grip strength in patients with lateral epicondylitis. Objectives 1. Does shock wave therapy reduce pain in patients with lateral epicondylitis? 2. Does shock wave therapy improve grip strength in patients with lateral epicondylitis? Method A literature review was performed in the databases PubMed, Cochrane, Cinahl and PEDro. Fourteen articles were found and critically reviewed. These articles were scored according to the PEDro scale and the scores were translated into a scale of evidence by the Statens Beredning för medicinsk Utredning (SBU) and the level of evidence was determined based on the four different grades presented by the SBU. Results According to the GRADE-system there was a strong scientific evidence for a reduction of pain using shock wave therapy in patients with lateral epicondylitis. Contradictory results whether shock wave therapy was better than placebo, corticosteoroid injection or tenotomy have been reported in studies of similar scientific quality. This means that more research is needed in this field. According to the GRADE-system there was a strong scientific evidence for an improvement of grip strength using shock wave therapy. Furthermore, there was a strong scientific evidence for that shock wave is not better than any other therapy in terms of improving grip strength in patients with lateral epicondylitis. Conclusion Shock wave therapy reduces pain in patients with lateral epicondylitis. There is, however, no evidence for shock wave therapy to be superior to any other treatment such as placebo, corticosteoroid injection or tenotomy. Shock wave therapy improves grip strenght but is not better than placebo, corticoidsteroid injection or tenotomy in increasing grip strength in patients with lateral epicondylitis.

INTRODUÇÃO E OBJETIVO: A disfunção erétil (DE) em pacientes transplantados renais é frequente. A modalidade de tratamento ideal não deve interferir com a função do enxerto. A terapia de onda de choque extracorpórea de baixa intensidade (TOCE) tem atraído interesse devido às suas propriedades angiogênicas e mostrou resultados interessantes quando usada para tratar pacientes com doença cardiovascular e em homens com DE. Nosso objetivo é estudar a eficácia e segurança da TOCE para o tratamento da DE de provável etiologia vascular em homens transplantados renais. MÉTODOS: Foram selecionados 20 homens (média de idade = 53,7 anos, 46 a 61 anos) que foram submetidos a transplante de rim há pelo menos 6 meses e com DE há pelo menos 6 meses. O estudo foi duplo-cego, realizado em um único centro, prospectivo, randomizado e placebo-controlado. Dez pacientes foram randomizados para o grupo de terapia placebo e 10 pacientes para o grupo TOCE .O protocolo da TOCE consistiu em 2 sessões de tratamento por semana durante 3 semanas. O tratamento placebo foi realizado utilizando o mesmo dispositivo, porém com substituição do probe eficaz por um sem emissão de energia, mas que proporcionava um som e uma sensação de pulso durante o tratamento. A avaliação pré-tratamento e do seguimento foi realizada com o Índice Internacional de Função Erétil-5 (IIEF-5) e Escore de Rigidez Peniana (EHS) após 1, 3 e 12 meses. Ultra-sonografia Doppler do pênis com fármaco ereção foi realizada antes da terapia e após o tratamento (3 meses). RESULTADOS: Não houve diferença entre estes dois grupos no escore basal do IIEF-5 e EHS. No início do estudo, 1 e 3 meses após o último tratamento, o IIEF-5 no grupo TOCE foi de 10,9 ± 5,1, 15,6 ± 6,1 e 17,2 ± 5,7, respectivamente. O IIEF-5 no grupo placebo foi de 14,9 ± 3, 16,6 ± 5,4 e 16,5 ± 5, respectivamente. O comportamento entre os 2 grupos ao longo do tempo foi significativamente estatistico (p=0,0177). A melhora do escore IIEF-5 foi superior a 5 pontos em 70% (variou de 1-14) dos pacientes no grupo TOCE e em 10% (variou de 0-10) dos pacientes no grupo placebo, 3 meses após o tratamento. A análise após 12 meses foi realizada exclusivamente no grupo TOCE. A alteração média no IIEF-5 após 12 meses foi de 4,8 no grupo TOCE. A média do IIEF-5 após 12 meses foi de 15,7 ± 6,45, mostrando estabilidade da melhora inicial. No início do estudo, 1 e 3 meses após o último tratamento, o EHS no grupo TOCE foi de 2 ± 1,05, 2,5 ± 0,85 e 2,6 ± 0,84, respectivamente. O EHS no grupo placedo foi de 2 ± 0,67, 2,4 ± 0,7 e 2,4 ± 0,7, respectivamente. Percebemos um comportamento semelhante nos dois grupos (p=0,724). No grupo TOCE, notamos um EHS médio um pouco maior após 3 meses. Os parâmetros da ultra-sonografia doppler peniana não diferiram entre os grupos e não apresentaram melhoras significativas. CONCLUSÕES: A TOCE é um tratamento não farmacológico com eficácia clínica em homens transplantados renais com DE. Além do seu potencial de reabilitação, é viável e eficaz. Não verificamos impacto nos parâmetros do doppler peniano apesar do efeito da neoangiogênese do método / INTRODUCTION AND OBJECTIVE: Erectile dysfunction (ED) in kidney transplant patients is frequent. The ideal treatment modality should not interfere with the graft function. Low-intensity Extracorporeal Shock Wave Therapy Extracorporeal (Li-ESWT) has been of interest due to its angiogenic properties and has shown interesting results when used to treat patients with cardiovascular disease and non-transplanted men with ED. Our objective is to study the efficacy of Li-ESWT for the treatment of ED of probable vascular etiology in kidney transplanted men. METHODS: Twenty men (mean age = 53.7 years, range 46 to 61 years) that have been submitted to kidney transplant for at least 6 months and have been suffering from ED for at least 6 months were selected for the treatment. This was a double-blinded, single-center, prospective, randomized, placebo-controlled trial. Ten patients were randomized into the placebo therapy arm and 10 patients into the Li-ESWT arm. The Li-ESWT protocol consisted of a 2 treatment sessions per week for 3 weeks. The placebo treatment was performed using the same device replacing the effective probe for one that emits zero energy, but delivers a sound and pulse sensation during treatment. Initial and follow-up assessment was performed with International Index of Erectile Function Questionnaire-5 (IIEF-5) score and Erection Hardness Score (EHS) after 1, 3 and 12 months. Penile ultrasound Doppler with drug erection was performed before therapy and after treatment (3 months). RESULTS: There was no difference between these 2 groups in baseline IIEF-5 score and EHS. At baseline, 1 and 3 months after the last treatment, the IIEF-5 in the Li-ESWT group were 10.9 ± 5.1, 15.6 ± 6.1 and 17.2 ± 5.7, respectively. The IIEF-5 in the sham therapy group were 14.9 ± 3, 16.6 ± 5.4 and 16.5 ± 5, respectively. The interaction was significant (p = 0.0177), indicating significantly different behaviors between the groups over time. The IIEF-5 score improved to higher than 5 points in 70% (range, 1-14) of the patients in the Li-ESWT group and 10% (range, 0-10) of the patients in the placebo treatment group, 3 months after treatment. The analysis after 12 months was performed exclusively in the Li-ESWT group. The mean change in IIEF-5 after 12 months was 4.8 in the Li-ESWT group. The mean of the IIEF-5 score after 12 months was 15.7 ± 6.45, showing stability of the initial improvement. At baseline, 1 and 3 months after the last treatment, the EHSs in the Li-ESWT group were 2±1.05, 2.5±0.85, and 2.6±0.84, respectively. The EHSs in the sham treatment group were 2±0.67, 2.4±0.7, and 2.4±0.7, respectively. We noticed a similar behavior in both groups (P=0,724). In the Li-ESWT group, we noticed a slightly higher mean EHS after 3 months. Penile Doppler ultrasound parameters did not differ between groups and did not show significant improvements. CONCLUSIONS: Li-ESWT is a non pharmacological treatment with clinical efficacy in kidney transplant recipients with ED. Besides its restorative potential, this treatment is feasible and effective. Despite evidences suggesting neoagiogenesis, our protocol had no impact in penile Doppler parameters

O objetivo da pesquisa foi avaliar os efeitos da terapia de ondas de choque extracorpórea em pacientes com osteoartrose coxofemoral secundária a displasia. Foram analisados 30 cães (Grupo I) com auxílio da plataforma de baropodometria, portadores de osteoartrose bilateral da articulação coxofemoral, que receberam como tratamento ondas de choque radiais somente em uma das articulações acometidas de modo aleatório que foi comparado ao membro contralateral com o acompanhamento de 3 meses, 18 animais (Grupo II) com displasia coxofemoral e osteoartrose bilateral medicados com condroprotetor e também comparado ao banco de 20 animais hígidos (Grupo III). O protocolo de tratamento envolveu três sessões de 2000 pulsos cada com frequência de 10 Hz de 2-3,4 bars, com intervalo de 7 dias, e a aplicação realizada sob sedação e curta anestesia. A avaliação mensal quantitativa do apoio dos membros e da eficácia do tratamento foi realizada com análise cinética utilizando sistema de baropodometria, mensurando-se o pico de força vertical (PFV) e o impulso vertical (IV).O grupo I e II tiveram em média valores do PFV e IV inferiores ao grupo III. No grupo I, observou-se um aumento em média de 10,6% do PFV e de 10,4% do IV do membro tratado, assim como uma melhora na simetria. O grupo II apresentou um aumento em média do membro pélvico esquerdo de 9% do IV, porém houve piora de 11% na simetria deste mesmo parâmetro. Os dados da análise cinética no membro tratado do grupo I atingiram em média valores próximos, mas ainda inferiores, ao grupo III de animais hígidos. Estas avaliações verificaram a eficácia das ondas de choque como tratamento conservativo de cães portadores de osteoartrose secundária a displasia, sugerindo efeitos benéficos de forma quantitativa para uma melhor locomoção. / The objective of this research was evaluate the extracorporeal shockwave therapy (ESWT) effects in patients with hip osteoarthritis secondary to hip dysplasia. Thirty dogs (Group I) with bilateral hip osteoarthritis were evaluated trough pressure walkway system. They had received unilateral radial shockwaves for treatment in random selection. The treated limb was compared with contra lateral limb during a follow up of 3 months. A comparison with the treated group with eighteen dogs under conservative treatment (Group II) and twenty healthy dogs (Group III) was also performed. Protocol treatment included three sessions of 2000 pulses each in a frequency of 10Hz with a pressure between 2 and 3.4 bar performed weekly using chemical restraint and short general anesthesia. Monthly assessment with kinetic analysis had done it with pressure walkway system. The peak of vertical force (PVF) and vertical impulse (VI) were measured. Group III kinetic analysis mean values were higher than groups I and II. Our results of group I suggest 10.6% of improvement in the treated limb in the PVF and 10.4% in the VI. In this group was also detected an improvement in the symmetry. The group II showed an improvement of 9% of VI only in the left pelvic limb but the symmetry decreased in 11% in this parameter. The kinetic analysis data of group I reached mean values of the treated limb close to healthy dogs of group III but remains slightly lower. These evaluations verified the efficacy of ESWT suggesting benefic quantitative effects in dog\'s locomotion.

Physics at extreme conditions is not a young field; there have been decades of developments that have allowed us to generate high-pressure and high-temperature conditions in a vast array of materials. Conventionally, these extreme conditions were generated using static compression techniques; compressing a material in a diamond anvil cell which could then be heated or cooled, with structural information deduced using synchrotron radiation. These techniques are still invaluable for extreme conditions research although the pressures and temperatures that are accessible to them are limited by the strength of the diamond anvil cells and their ability to withstand extreme temperatures. The necessity for access to pressure-temperature states that are beyond the scope of the conventional diamond anvil cell is driven by the need to characterise extreme environments such as planetary interiors. It was long believed that materials in high pressure-temperature states would exhibit relatively simple, high-symmetry crystal structures, but recent research has proven that, conversely, there is an abundance of complex structural behaviour at these extreme conditions. One means of attaining pressure-temperature states beyond those accessible using static compression techniques is to impart a large amount of energy into a material in a comparatively short period of time (milliseconds to nanoseconds); this is known as dynamic compression. Dynamic compression can be generated using impact techniques or, alternatively, via laser ablation. Access to the most extreme conditions is commonly achieved by generating a shockwave which compresses the sample with the fastest achievable compression wave. Not only does this type of compression facilitate access to the most extreme states, it also allows us to explore the physics of impact phenomena and other such situations involving rapid energy transfer. Dynamic compression occurs on short timescales and, as such, there is a considerable challenge in implementing diagnostics to study the behaviour of compressed materials. Furthermore, because complexity is commonplace in extreme conditions, it is vital that any diagnostics should be able to provide data of high enough quality that this complexity may be resolved. The advent of 4th generation light sources (x-ray free electron lasers) has afforded us the opportunity to obtain extraordinarily high quality data on dynamic compression timescales. In the interest of refining analytical techniques when utilising this novel technology, materials exhibiting complex crystal structures should be investigated. Antimony is an element which is known, under static compression, to transform from a Peierls-distorted rhombohedral phase (R-3m) to an incommensurately modulated host-guest structure (I'4=mcm(00γ)000s), a structure with an incredibly high level of complexity. The complexity of this host-guest phase, and the relatively low pressure at which it forms, makes antimony an ideal candidate for testing the resolution achievable using these 4th generation light sources. Furthermore, it is interesting to observe whether such a complex phase can form on the short timescales of dynamic compression. In this work antimony is both statically and dynamically compressed and the results of both experiments are compared. A static phase diagram is constructed for antimony up to 31 GPa and 835 K, confirming the location of a previously theorised triple point and suggesting the location of an additional triple point. Three solid phases are characterised and data are found to agree with the pre-existing static compression studies. The nature of the host-guest phase is investigated and the guest 'chains' are found to remain intact even at the highest temperatures and pressures, a result which has not previously been observed in high pressure-temperature host-guest structures. Dynamic data from shock-compression experiments at pressures up to 59.3 GPa are plotted alongside the static data and contrasting phase behaviour is discussed. Four solid phases are identified along with one liquid phase. Observation of the host-guest phase in shock-compressed antimony confirms that highly complex crystal structures are able to form on the nanosecond timescale.

O objetivo da pesquisa foi avaliar os efeitos da terapia de ondas de choque extracorpórea em pacientes com osteoartrose coxofemoral secundária a displasia. Foram analisados 30 cães (Grupo I) com auxílio da plataforma de baropodometria, portadores de osteoartrose bilateral da articulação coxofemoral, que receberam como tratamento ondas de choque radiais somente em uma das articulações acometidas de modo aleatório que foi comparado ao membro contralateral com o acompanhamento de 3 meses, 18 animais (Grupo II) com displasia coxofemoral e osteoartrose bilateral medicados com condroprotetor e também comparado ao banco de 20 animais hígidos (Grupo III). O protocolo de tratamento envolveu três sessões de 2000 pulsos cada com frequência de 10 Hz de 2-3,4 bars, com intervalo de 7 dias, e a aplicação realizada sob sedação e curta anestesia. A avaliação mensal quantitativa do apoio dos membros e da eficácia do tratamento foi realizada com análise cinética utilizando sistema de baropodometria, mensurando-se o pico de força vertical (PFV) e o impulso vertical (IV).O grupo I e II tiveram em média valores do PFV e IV inferiores ao grupo III. No grupo I, observou-se um aumento em média de 10,6% do PFV e de 10,4% do IV do membro tratado, assim como uma melhora na simetria. O grupo II apresentou um aumento em média do membro pélvico esquerdo de 9% do IV, porém houve piora de 11% na simetria deste mesmo parâmetro. Os dados da análise cinética no membro tratado do grupo I atingiram em média valores próximos, mas ainda inferiores, ao grupo III de animais hígidos. Estas avaliações verificaram a eficácia das ondas de choque como tratamento conservativo de cães portadores de osteoartrose secundária a displasia, sugerindo efeitos benéficos de forma quantitativa para uma melhor locomoção. / The objective of this research was evaluate the extracorporeal shockwave therapy (ESWT) effects in patients with hip osteoarthritis secondary to hip dysplasia. Thirty dogs (Group I) with bilateral hip osteoarthritis were evaluated trough pressure walkway system. They had received unilateral radial shockwaves for treatment in random selection. The treated limb was compared with contra lateral limb during a follow up of 3 months. A comparison with the treated group with eighteen dogs under conservative treatment (Group II) and twenty healthy dogs (Group III) was also performed. Protocol treatment included three sessions of 2000 pulses each in a frequency of 10Hz with a pressure between 2 and 3.4 bar performed weekly using chemical restraint and short general anesthesia. Monthly assessment with kinetic analysis had done it with pressure walkway system. The peak of vertical force (PVF) and vertical impulse (VI) were measured. Group III kinetic analysis mean values were higher than groups I and II. Our results of group I suggest 10.6% of improvement in the treated limb in the PVF and 10.4% in the VI. In this group was also detected an improvement in the symmetry. The group II showed an improvement of 9% of VI only in the left pelvic limb but the symmetry decreased in 11% in this parameter. The kinetic analysis data of group I reached mean values of the treated limb close to healthy dogs of group III but remains slightly lower. These evaluations verified the efficacy of ESWT suggesting benefic quantitative effects in dog\'s locomotion.

No description available.

No description available.

Ce travail de thèse concerne l’utilisation des décharges électriques de haute tension (DEHT) en milieu aqueux comme méthode d’extraction des polyphénols à partir de pépins de raisin.Les arcs électriques produits en milieu aqueux provoquent une succession de phénomènes (ondes de choc, bulles de cavitation) qui ont pour effet de fragmenter toute matière première située à proximité de l’arc électrique. L’objectif de cette thèse est d’étudier ces phénomènes afin d’améliorer la compréhension et l’efficacité des DEHT en tant que méthode d’extraction.Dans un premier temps, une étude des conditions d’apparition de l’arc électrique dans l’eau a permis de montrer que l’arc apparaît initialement dans des bulles de vapeur générées à la surface de l’électrode à cause de l’échauffement du liquide par effet Joule. Des mesures électriques, des prises de vues à haute vitesse, ainsi qu’une simulation numérique du problème ont permis de vérifier cette hypothèse. Une étude paramétrique des phénomènes générés par l’arc électrique (onde de choc et bulle de cavitation) a été menée. Grâce à des mesures de la pression des ondes de choc, des mesures de la taille des bulles de cavitation, et grâce des mesures électriques précises (notamment de la résistance électrique de l’arc), il apparaît que l’amplitude des phénomènes dépendent essentiellement de l’énergie dépensée dans l’arc. Cette énergie doit être distinguée de l’énergie totale d’une impulsion électrique, dont une partie est dépensée avant le claquage, mais également de l’énergie disponible au moment du claquage, dont une partie importante est dépensée dans le circuit électrique. La partition de cette énergie entre l’arc et le circuit électrique dépend du rapport entre la résistance du circuit et la résistance de l’arc. Ainsi une méthode pour augmenter significativement l’amplitude des phénomènes étudiés, et donc l’efficacité du procédé est d’améliorer le rapport entre ces résistances. Il a par exemple été observé qu’en augmentant la longueur de l’arc électrique de 2.5 mm à 2 cm, la résistance de l’arc augmente de 40 m à 0.55, et l’amplitude de l’onde de choc augmente de 135%. Pour finir, une étude paramétrique sur l’efficacité des DEHT comme procédé d’extraction des polyphénols des pépins de raisin a été menée. Entre autres, les effets sur l’extraction de la conductivité du liquide, du rapport liquide-solide, du nombre d’impulsion, de l’énergie par impulsion, de la distance inter-électrode ont été étudiés. Ces études ont mis en évidence l’importance de la répartition de l’énergie totale d’une impulsion en énergie dépensée avant le claquage, énergie dépensée au claquage dans le circuit électrique et énergie dépensée dans l’arc électrique. Ces études ont montré comment cette répartition est influencée par ces différents paramètres, et comment cela influence l’efficacité d’extraction. L’influence de la distance inter-électrode, et donc de la longueur de l’arc, a été particulièrement été mise en évidence par les résultats d’extraction. / This thesis work focuses on the use of high voltage electrical discharges (HVED) in aqueous media as a method for extracting polyphenols from grape seeds. Electric arcs generated in an aqueous environment cause a succession of phenomena (shock waves, cavitation bubbles) that have the effect of fragmenting any raw material located near the electric arc. The objective of this thesis is to study these phenomena in order to improve the understanding and effectiveness ofHVED as an extraction method. First, a study of the conditions under which the electric arc appears in water showed that the arc initially appears in vapour bubbles generated on the electrode surface due to the heating of the liquid due to Joule effect. Electrical measurements, high-speed photography and a numerical simulation of the problem have allowed this hypothesis to be verified. A parametric study of the phenomena generated by the electric arc (shock wave and cavitation bubble) was carried out. Through measurements of shock wave pressure, of cavitation bubble size, and precise electrical measurements (including the electrical resistance of the arc), it appears that the amplitude of the phenomena depends essentially on the energy consumed in the arc. This energy mustbe distinguished from the total energy of an electrical pulse, part of which is spent before the breakdown. The energy spent in the electric arc must also be distinguishedfrom the energy available at electrical breakdown, as a significant part of breakdown energy is spent in the electrical circuit. The partition of breakdown energy between the arc and the electrical circuit depends on the ratio between the resistance of the circuit and that of the arc. Thus a method to significantly increase the amplitude of the studied phenomena (and therefore the efficiency of the process), is to improve the ratio between these resistances. For example, it has been observed that by increasing the length of the electric arc from 2.5 mm to 2 cm, the resistance of the arc increases from 40 m to 0.55, and the amplitude of the shock wave increases by 135%. Finally, a parametric study on the efficiency of DEHT as a process for extracting polyphenols from grape seedswas carried out. Among other things, the effects on the extraction of liquid conductivity, liquid-solid ratio, number of pulses, energy per pulse, and distance between electrodes were studied. These studies highlighted the importance of the distribution of the total pulse energy into energy spent before the breakdown, energy spent after breakdown in the electrical circuit and energy spent in the arc. These studies have shown howthis distribution is influenced by these different parameters, and how it influences extraction efficiency. The influence of the inter-electrode distance, and therefore the length of the arc, was particularly highlighted by the extraction results.

L'objectif de cette thèse était d'explorer de nouvelles applications cardiaques pour l'histotripsie et de développer les outils permettant leur mise en place non-invasive. La thérapie ultrasonore cardiaque est en effet encore assez peu développée aujourd’hui, à cause de la difficulté à traiter un organe en mouvement permanent, et très bien protégé derrière la cage thoracique.Nous avons d'abord montré in vivo, sur un modèle ovin, que l’on pouvait sectionner les cordages mitraux de manière non-invasive ainsi que traiter la sténose aortique calcifiée. Engendrer de la cavitation sur les feuillets valvulaires permet effectivement d’agir à distance sur les calcifications, et de globalement assouplir la valve.Simultanément, nous avons développé un dispositif pour la thérapie cardiaque non invasive, fondé sur le concept de cavité à retournement temporel. Ce dispositif permet l'émission d'impulsions ultrasonores de haute intensité dans un très grand volume d’intérêt. L’on peut ainsi déplacer le point de thérapie en 3 dimensions de manière entièrement électronique, et sans déplacer mécaniquement l’appareil. Après optimisation, ce dispositif a permis de créer des lésions mécaniques bien contrôlées dans une région d'intérêt de 2 000 cm3.Pour faire face au défi que représente la cage thoracique, nous avons développé une méthode de focalisation adaptative et l'avons mise en œuvre dans un prototype 2D du dispositif. Avec cette méthode, nous pouvons non seulement construire un front d'onde ultrasonore adaptatif qui se propage de manière préférentielle à travers les espaces intercostaux, mais grâce aux propriétés des cavités à retournement temporel, nous pouvons également augmenter la pression focale obtenue sur la cible de thérapie.Enfin, pour approfondir ce travail sur la focalisation adaptative, et nous avons considéré le cas de l'imagerie transcrânienne. Pour cette application, nous avons choisi d’utiliser la focalisation par retournement temporel dans le bruit de speckle, pour corriger les aberrations induites par le crâne. En simulations numériques, nous avons pu calculer les modulations de phase et d'amplitude induites par les os et améliorer le contraste et la résolution d'une image B-mode. / The objective of this thesis was to explore new applications for cardiac histotripsy, and to develop the tools making it possible non-invasively. Cardiac ultrasound therapy indeed still remains limited due to the tremendous challenge of treating a constantly and rapidly moving organ, well protected behind the ribcage.We first showed in vivo, on a large animal model, that histotripsy could be used non-invasively to cut mitral chordae, and to treat calcified aortic stenosis in a beating heart. Cavitation on the valve leaflets can indeed locally and remotely act on the calcifications, and globally soften the valve. Simultaneously, we developed a therapeutic device allowing completely non-invasive cardiac shock-wave therapy based on the time reversal cavity concept. In particular, this device allows the emission of high intensity ultrasound pulses, and provides 3D electronical steering of the therapy focal spot in a large volume. After a thorough optimisation process, this device was capable of creating well controlled mechanical lesions over a 2 000 cm3 region of interest. To tackle the challenge of ultrasound propagation through the rib cage, we developed an adaptive focusing method (DORT method through a time reversal cavity), and implemented it in a 2D prototype of the device. With this method, we not only could build an adaptive ultrasonic wavefront propagating preferentially through the intercostal spaces, but due to time reversal cavities properties, we could also increase the peak pressure obtained on target.Finally, we pushed our work on adaptive focusing further, and considered the case of transcranial imaging. For this application, we chose to use the time reversal of speckle noise technique, to correct the aberrations induced by the skull. In numerical simulations, we were able to derive the phase and amplitude modulations induced by the bones, and could improve the contrast and resolution of a B-mode image.

Η επιρροή του παράγοντα χρονοαπόσταση σε ένα σύστημα ακολουθίας οχημάτων μπορεί να προσδιορίσει την επικινδυνότητα του πλήγματος που υφίσταται το σύστημα. Με βάση μια παρ’ολίγον οπισθο-μετωπική σύγκρουση σε αυτοκινητόδρομο 3 λωρίδων, εξετάζεται ο ρόλος της χρονοαπόστασης μεταξύ των οχημάτων σε συνδυασμό με τους χρόνους αντίδρασης των οδηγών στην αντίληψη του επικείμενου κινδύνου. Το μοντέλο ακολουθίας οχημάτων κατά Brill, που συσχετίζει την χρονοαπόσταση, τον χρόνο αντίδρασης του οδηγού και την επιβράδυνση με τη συχνότητα των ατυχημάτων, χρησιμοποιείται ως κύριο εργαλείο για την εκτίμηση της ευαισθησίας της πιθανότητας ενός ατυχήματος. Μέσω της μικροσκοπικής ανάλυσης του βίντεο καταγραφής του ατυχήματος και της επεξεργασίας των δεδομένων και με πηγή έμπνευσης τα προγενέστερα επίμαχα ερωτήματα που θέτει και απαντά ο G. Davis και οι συνεργάτες του, προκύπτουν οι απαραίτητες πληροφορίες για την αριθμητική περιγραφή του ατυχήματος. Με τη χρήση έπειτα του λογισμικού προγράμματος OpenBUGS, το οποίο βασίζεται στη μέθοδο Monte Carlo Markov Chain, γίνεται προσομοίωση του προτύπου ατυχήματος και υπολογίζονται οι τιμές των παραμέτρων που επηρεάζουν τη μορφή του πλήγματος. Από τα αποτελέσματα προκύπτει ο βαθμός που ο συνδυαστικός παράγοντας χρονοαπόσταση και χρόνος αντίδρασης επηρεάζει το πλήγμα και αξιολογείται. Τέλος, με συγκεκριμένες επεμβάσεις επιχειρείται η βελτίωση ολόκληρου του συστήματος ακολουθίας οχημάτων. / The influence of time headway on a car-following system can determine the severity of a shockwave. Based on a near-miss rear-end collision on a 3-lane highway, this study examines the importance of time headway in combination with the driver’s reaction time upon perception of the upcoming hazard. The car-following model developed by Ed. Brill, relating driver’s reaction time, temporal headway and deceleration response to accident frequency, is used as a main tool for assessing the sensitivity of collision probability. Through a microscopic analysis of the video record and data processing and inspired by earlier critical questions that G. Davis and his associates have posed and answered, all the necessary information for the arithmetical description of the accident is extracted. Using the OpenBUGS software, and based on the Monte Carlo Markov Chain method, simulation of the collision prototype is achieved along with the calculation of other main parameters that affect the shockwave form. Simulation results, revealing the influence that the combined factor headway-reaction time has on a shockwave are derived and evaluated. Through certain modifications, the improvement of the whole car-following system is attempted.