Little research has been done to validate the biomechanical principles of tibial tuberosity advancement (TTA) throughout stance. The present study evaluates the effects of TTA on kinematics of the cranial cruciate (CrCL) deficient stifle during early, middle, and late stance. Cadaveric pelvic limbs were evaluated for the effects of TTA on kinematics under a load equivalent to 30% bodyweight and under the following treatment conditions: intact CrCL, CrCL deficient, TTA-treated, and TTA treated + meniscal release. Electromagnetic tracking sensors were used to determine tibial subluxation and rotation relative to the femur. Transection of the CrCL resulted in significant cranial tibial subluxation during early, middle, and late stance and significant internal rotation during early and middle stance. TTA normalized tibial subluxation in early, middle, and late stance but was unsuccessful in normalizing axial rotation in middle stance. Meniscal release had no effect on cranial/caudal or rotational displacement when performed following TTA.

No description available.

Le traitement et la gestion de la douleur sont depuis toujours une priorité pour le corps médical. Malgré leur importance pour la qualité de vie, les analgésiques couramment utilisés possèdent un ratio bénéfice/risque faible. La recherche de nouveaux concepts thérapeutiques pour lutter contre la douleur est donc une priorité. Afin de répondre à ce besoin, il faut d'abord comprendre les mécanismes de la perception de la douleur ainsi que, plus globalement, ceux permettant de percevoir son environnement. Dans ce contexte, de nombreuses études ont mis en évidence l'implication du canal calcique à bas seuil Cav3.2 dans les voies de la transmission de l'information douloureuse. Il représente donc une cible de choix pour le traitement de la douleur mais l'identité des neurones exprimant ces canaux ainsi que la fonction de Cav3.2 dans la physiologie des neurones sensoriels étaient jusqu'à présent inconnues. Au cours de cette thèse nous avons dans un premier temps décrit un nouvel inhibiteur des canaux calciques à bas seuil : le TTA-A2. Nous avons ainsi démontré que le TTA-A2 est un inhibiteur spécifique des canaux Cav3.1, Cav3.2, et Cav3.3. Il permet de diminuer l'excitabilité des neurones sensoriels exprimant Cav3.2, ce qui provoque une analgésie sur des animaux sains et pathologiques. Dans un deuxième temps nous nous sommes servis de ce nouvel outil en parallèle d'un nouveau modèle murin possédant une étiquette fluorescente (Knock in GFP) sur le canal Cav3.2 pour explorer la localisation et la fonction de Cav3.2 dans les neurones sensoriels. Nous avons ainsi découvert que Cav3.2 est exprimé dans des mécanorécepteurs à bas seuil impliqués dans la perception des stimuli mécaniques et thermiques nocifs ou non-nocifs. Le canal en lui-même se trouve aux endroits clés de la genèse et de la propagation du message nerveux périphérique, et module le seuil et la vitesse de conduction des potentiels d'action. Replacé dans le contexte de la bibliographie, l'ensemble de nos résultats montre que Cav3.2 permet de donner la modalité à bas seuil aux neurones l'exprimant. / Pain management and treatment have always been a priority for life quality. Despite this fact, analgesics commonly used present a bad benefice/risk ratio. Discovery of new therapeutic concepts to fight pain is highly required. To complete this task, we first need to better understand pain perception mechanisms, and more globally, mechanisms involved in the perception of our environment. In this context, numerous studies have shown that low threshold calcium channels Cav3.2 are involved in pain information transmission. Thus, it represents a good target for the treatment of pain. However, neuronal identity of Cav3.2-expressing sensory neurons and Cav3.2 functions in neuronal physiology are unknown. During this PhD we first described a new low voltage activated channel antagonist named TTA-A2. We demonstrated that TTA-A2 is a powerful nanomolar specific agonist of Cav3.1, Cav3.2 and Cav3.3. This molecule is able to reduce excitability in sensory neurons expressing Cav3.2, and is able to generate a strong analgesic effect on naive and pathologic animals. In the other part of this PhD, we used this new tool combined to a new transgenic mouse that expressed Cav3.2 tagged with a fluorescent protein (Knock-in GFP). With these new tools we discovered that Cav3.2 is expressed in low threshold mechanoreceptors involved in detection of painful and non painful mechanical and thermal stimuli. Cav3.2 itself is expressed at key localisations that allow action potential generation and propagation, and modulate threshold and speed conduction of action potential. Taken together, these results show that Cav3.2 gives the “low threshold” modality to neurons.

V této práci je navrhnut energeticky úsporný procesor typu TTA (Transport Triggered Architecture) pro výpočet rychlé Fourierovy transformace (FFT). Návrh procesoru byl vytvořen na míru použitému algoritmu pomocí speciáoních funkčních jednotek. Algoritmus byl realizován jako posloupnost instrukcí tak, že většina výpočtu probíhá ve smyčce obrahující pouze jedionu paralelní instrukci. Tato instrukce je umístěna do instrukčního bufferu, odkud je potom volána místo instrukční paměti. Díky tomu se dá docílit nižší spotřeby, neboť volání z instrukčního bufferu je efektivnější než volání z instrukční paměti. Program byl zkompilován na časovém modelu procesoru a časová simulace potvrdila správnost návrhu. Součástí práce jsou rovněž pomocné programy v Pythonu, které slouží ke generaci referenčních výsledků a automatické simulaci a porovnání výsledků simulace s referencí.

Der Riss des vorderen Kreuzbandes ist die häufigste Lahmheitsursache der Hintergliedmaße beim Hund. In der Literatur werden verschiedene Operations-methoden zur Therapie des Kreuzbandrisses beschrieben. Ein dynamisches Verfah-ren stellt hierbei die TTA (Tibial Tuberosity Advancement) dar. Bei dieser Operation wird die Crista tibiae kranial verlagert, um einen Patellarsehnenwinkel (PTA) von 90° zum Tibiaplateau zu erreichen. In in vitro Untersuchungen konnte damit eine Aufhebung der kranio-kaudalen Scherkräfte, welche bei einem kreuzbandinsuffizienten Kniegelenk vorliegen, erreicht und die Stabilität des Kniegelenkes nach TTA wieder hergestellt werden. Ungeachtet dessen bestehen Hinweise auf eine persistierende Instabilität in vivo. Anhand der fluoroskopischen Kinematografie erfolgte eine Bewegungsanalyse der Kniegelenke von Hunden in vivo nach klassischer TTA sowie TTA-2. Zudem wurden mögliche Einflussfaktoren hinsichtlich des Erfolges der TTA-Technik untersucht. Die Arbeit ist in zwei Studien unterteilt. In der 1. Studie erfolgte die retrospektive Untersuchung von 10 Hundekniegelenken nach traditioneller TTA. Im Gegensatz dazu bezog sich die prospektive Studie 2 auf Kniegelenke nach einer TTA-2 Operation (n = 15). Die Hunde wurden orthopädisch untersucht und wiesen praeoperativ einen kompletten kranialen Kreuzbandriss auf. In der Arthroskopie bestätigte sich der komplette Riss und es erfolgte eine Untersuchung der Menisken, gegebenenfalls mit anschließender Meniskuschirurgie. In beiden Studien wurden die Hunde unilateral und uniplanar fluoroskopisch-kinematografisch untersucht, während sie im Schritt auf einem Laufband geführt wurden. Je Patient erfolgte eine Ganganalyse prae- und eine weitere 6-8 Wochen post operationem. Die Röntgenvideoaufnahmen wurden visuell von drei verschiedenen Untersuchern auf das Vorliegen einer kranio-kaudalen Translation beurteilt. Weiterhin wurden von allen Tieren der prae- und postoperative PTA sowie der Extensionswinkel bestimmt. Da ein aus der Literatur bekannter möglicher Einflussfaktor eine Unterkorrektur (PTA > 90°, zu kleine Cage-Größe) ist, wurde in der Studie 2 bei der Operationsplanung auf das Erreichen eines PTA ≤ 90° geachtet. In Studie 1 lag das mittlere Alter der Patienten bei 4,7 Jahren und das Gewicht bei 27,3 kg. Bei der arthroskopischen Untersuchung wiesen vier Gelenke Meniskusläsionen auf. Die postoperative Ganganalyse zeigte bei 90 % (9 von 10) eine persistierende Instabilität nach TTA, wobei der mittlere PTA 92,4° betrug. In der Studie 2 hatten die Tiere ein mittleres Alter von 7,0 Jahren und ein Gewicht von 31,2 kg. Bei der Mehrzahl der Patienten (n = 11) konnte ein Meniskusschaden diagnostiziert werden, wobei hauptsächlich mediale Korbhenkelrisse eine Rolle spielten. Die fluoroskopische Kinematografie zeigte bei 73,3 % der Patienten eine bestehende Instabilität nach TTA-2. Der mittlere PTA lag bei 88,5°. Im Gegensatz zu den Ergebnissen der in vitro Untersuchungen ist die überwiegende Anzahl der Kniegelenke nach Versorgung eines kranialen Kreuzbandrisses mit TTA bzw. TTA-2 persistierend instabil. Ungeachtet dessen wiesen alle Patienten eine klinische Verbesserung der Lahmheit auf. Während die Er-gebnisse der Studie 1 noch eine Unterkorrektur (postoperativer PTA > 90°) als mögliche Ursache für die Kniegelenksinstabilität nahelegen, konnte dies im Rahmen der Studie 2 wiederlegt werden. Inwieweit die Menisken als stabilisierender Faktor eine Rolle spielen, kann anhand der vorliegenden Arbeit nicht eindeutig geklärt werden. / Cranial cruciate ligament ruptures are the most common cause of hind limb lameness in dogs. Various surgical therapeutical methods are described in the literature to successful cure the cranial cruciate ligament rupture. Amongst those the dynamic technique TTA (tibial tuberosity advancement) is described. During this procedure, the Crista tibiae is shifted cranially to produce a patellar tendon angle (PTA) of 90°. It has been shown during in vitro studies that cranio-caudal shear forces that occur after cranial cruciate ligament rupture are clearly neutralized. This results in a completely stable stifle after TTA. However, evidence for persistent instabilities after TTA exist in vivo. Fluoroscopic gait analysis of the canine stifle in vivo after treatment with classical TTA and TTA-2 was performed. Furthermore, potential factors influencing a successful outcome of the TTA-technique were examined. This study is subdivided in two parts. During the 1st study a retrospective analysis of 10 canine stifles after classical TTA was undertaken, while the 2nd study was performed prospectively on stifles treated with a TTA-2 (n = 15). The dogs were examined orthopedically prior to surgery and suffered from a complete cranial cruciate ligament rupture. This was confirmed by arthroscopy which was further used to evaluate the meniscal status and to perform a meniscal surgery, if necessary. Fluoroscopic-kinematographic gait analyses were carried out prior to and 6-8 weeks after TTA by unilateral and uniplanar recording on all dogs while they were walking on a treadmill. The video sequences were analysed regarding the presence or absence of cranio-caudal movement by three independent investigators. Moreover, the pre- and post-surgical PTA and stifle angle were recorded. According to the literature undercorrected stifles (PTA > 90°, inappropriate small cage size) were identified as a possible cause of post-surgical instability. Therefore, special emphasis paid on surgical planning during study 2 to achieve a PTA ≤ 90° by TTA-2. The mean age of the patients in the 1st study was 4.7 years and their mean body weight 27.3 kg. Four joints showed meniscal lesions during the arthroscopic examination. During fluoroscopic gait analysis a persistent instability after TTA was present in 90 % (9 of 10) of the stifles. The median PTA was 92.4°. In the 2nd study the mean body weight was 31.2 kg and the mean age 7.0 years. Meniscal injuries were diagnosed in the majority of the patients (n = 11). Most of them were suffering from medial bucket handle tears. After performing TTA-2 73.3 % of the stifles showed a persistent instability during the fluoroscopic gait analysis. The mean PTA was 88.5°. Contrary to the results of in vitro studies, the majority of stifles after treatment of a cranial cruciate ligament rupture with a TTA or TTA-2 remain to be persistently instable. Nevertheless, all dogs clinically improved regarding the degree of lameness. While the results of the 1st study suggest an undercorrection (post-surgical PTA > 90°) as a possible cause of stifle instability, this could not be proven during the 2nd study. The role of the menisci as a stabilizer of the canine stifle could not be finally elucidated by the present work.

The photophysical properties of a series of Zn (II) porphyrins adsorbed onto a semiconductor were investigated using steady-state absorbance and emission measurements. The ability of the porphyrins to undergo triplet-triplet annihilation (TTA), a photophysical process through which photons in the red and near-infrared (NIR) regions of the optical spectrum can be converted into higher energy photons (upconversion), was explored. Aggregation capabilities were determined to verify possibility of these molecules to undergo triplet-triplet annihilation (TTA). TTA has significant potential for increasing the efficiency of dye-sensitized solar cells (DSSCs) by upconverting photons in the energy rich NIR region of the solar spectrum. A key requirement for efficient TTA is aggregation of the sensitizer dye, and in this thesis, we have examined the aggregation of porphyrins in TiO2-based sol-gel films. Solution phase absorption and emission studies were conducted using zinc (II) tetraphenylporphyrin and three of its functionalized derivatives, tetra(4-aminophenyl)porphyrin Zn(II), tetra(4-carboxyphenyl)porphyrin Zn(II), and tetra(4-sulfonatophenyl)porphyrin Zn(II), to evaluate their potential as DSSC sensitizers on TiO2 thin films. Mesoporous TiO2 thin films were synthesized, using a polymer-templating sol-gel route, and characterized with tunneling electron microscopy (TEM), atomic force microscopy (AFM), and UV-Vis absorbance measurements. Spectroscopy measurements were also carried out on porphyrin-sensitized TiO2 thin films and compared to solution-based results. A simple DSSC was constructed and used to further explore the application of zinc (II) porphyrin sensitizers in photovoltaic applications.

The Niagara Foot (NF) is a relatively new prosthetic design, primarily intended for use in developing countries. It combines low cost and durability with high performance energy return features. The design has been successfully tested mechanically and in field trials, but to date there has been little quantitative gait data describing the performance of the foot. Biomechanical gait analysis techniques will be used to extract quantitative gait measures. The current study is designed to characterize the effect of heel section stiffness parameter differences between a NF normal heel and a NF with a reduced material heel section., on gait characteristics in persons with unilateral trans-tibial amputations (TTA). Standardized biomechanical gait analysis techniques, adapted for this population, were used to extract quantitative gait measures. Five persons with TTA performed walking tasks while 3D ground reaction forces were recorded via an embedded force platform. A motion capture system also recorded the 3D segmental motion of the lower limbs and torso of each subject. These were combined to calculate net joint moments and mechanical power at the hip and knee of both limbs. These data were compared between a normal NF and a NF with a modified heel. Each participant had a period of two-week adaptation prior to any testing. An EMG system and a prosthesis evaluation questionnaire were used to help analyze the condition. The overall hypothesis of this study was that modification of the heel section stiffness would change several aspects of gait. Although the gait pattern differences between participants and the low participant number produced no significant differences between the conditions for all variables, trends were observed in multiple outcomes. These results report preliminary evidence that for some participants the heel material reduction does impact their gait by showing a different loading phase during the transition between the heel strike and the full contact with the ground. The NF2 may move the gait toward a more flexed knee position. Furthermore, despite a reduction in the material of the heel section results showed that the overall foot stiffness increased. This may be the result of the one-piece design and mechanics of the NF. Further investigations with a bigger cohort of people with TTA are required to look at the importance of the impact of the prosthetic foot heel stiffness.

The Niagara Foot (NF) is a relatively new prosthetic design, primarily intended for use in developing countries. It combines low cost and durability with high performance energy return features. The design has been successfully tested mechanically and in field trials, but to date there has been little quantitative gait data describing the performance of the foot. Biomechanical gait analysis techniques will be used to extract quantitative gait measures. The current study is designed to characterize the effect of heel section stiffness parameter differences between a NF normal heel and a NF with a reduced material heel section., on gait characteristics in persons with unilateral trans-tibial amputations (TTA). Standardized biomechanical gait analysis techniques, adapted for this population, were used to extract quantitative gait measures. Five persons with TTA performed walking tasks while 3D ground reaction forces were recorded via an embedded force platform. A motion capture system also recorded the 3D segmental motion of the lower limbs and torso of each subject. These were combined to calculate net joint moments and mechanical power at the hip and knee of both limbs. These data were compared between a normal NF and a NF with a modified heel. Each participant had a period of two-week adaptation prior to any testing. An EMG system and a prosthesis evaluation questionnaire were used to help analyze the condition. The overall hypothesis of this study was that modification of the heel section stiffness would change several aspects of gait. Although the gait pattern differences between participants and the low participant number produced no significant differences between the conditions for all variables, trends were observed in multiple outcomes. These results report preliminary evidence that for some participants the heel material reduction does impact their gait by showing a different loading phase during the transition between the heel strike and the full contact with the ground. The NF2 may move the gait toward a more flexed knee position. Furthermore, despite a reduction in the material of the heel section results showed that the overall foot stiffness increased. This may be the result of the one-piece design and mechanics of the NF. Further investigations with a bigger cohort of people with TTA are required to look at the importance of the impact of the prosthetic foot heel stiffness.

This dissertation presents the results of research towards a new computer architectural approach for the construction of digital signal processors. The new approach is based on a transport triggered architecture (TTA) and allows for a dataflow processing mode. The proposed architecture has beed called TAD (Transport triggered Architecture with Dataflow-extension). The designed machine is able to execute limited dataflow-graphs using a single assembly instruction. The size of the dataflow-graph is limited by the number of available execution units and communication resources. To undertake the research a cycle-correct simulator of the proposed microarchitecture has been designed. Benchmark results of the new microarchitecture were obtained by executing typical DSP-programs on the simulator. The properties of the new architecture and the variants of its parameters are discussed in the text. i Performance data is given on a per-cycle basis. A demonstration machine for the TAD has been synthesized for a 0.35um CMOS-technology. Data for area and maximum clock frequency of the design have been extracted from the routed chip design. / Diese Arbeit stellt die Ergebnisse von Untersuchungen über eine neue Architekturvariante für digitale Signalverarbeitungsprozessoren mit transportgesteuerter Architektur (TTA) vor. Die dazu entworfene Maschine erlaubt es, endliche Datenflussgraphen auf einen einzelnen Maschinenbefehl abzubilden. Die maximale Größe der abbildbaren Datenflussgraphen ist dabei durch die Anzahl gleichzeitig verfügbarer Verarbeitungseinheiten und Kommunikationsresourcen beschränkt. Die Untersuchungen dazu wurden mit einem taktgenauen Mikroarchitektursimulator durchgeführt. Die Daten zur Verarbeitungsleistung der Maschine wurden durch das Ausführen von Lastprogrammen auf diesem Simulator gewonnen. Der Aufbau und die Eigenschaften der durch den Simulator realisierten Mikroarchitektur und einige von dieser Implementation abweichende Varianten werden erläutert. Da sich Angaben zur Anzahl der Verarbeitungszyklen nicht vergleichen lassen, ohne dass Informationen zur maximal erreichbaren Taktfrequenz der Implementation vorliegen, wurde die vorgeschlagene Mikroarchitektur als integrierter Schaltkreis synthetisiert, um Informationen zu Flächenbedarf und Laufzeit zu gewinnen. Aus den Entwurfsdaten für den integrierten Schaltkreis wurden die Verdrahtungs-Kapazitäten extrahiert und daraus die Information zur maximalen Taktfrequenz gewonnen.

Made available in DSpace on 2014-10-09T12:45:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:32Z (GMT). No. of bitstreams: 1 07315.pdf: 7984048 bytes, checksum: 44e14c94f410e590257d081e9053a3c1 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo