Introduction : l’innervation et la vascularisation des corps caverneux du pénis sont très difficilement explorables par les techniques de dissection anatomiques classiques. De ce fait, elles demeurent pas très bien connues. La dissection anatomique assistée par ordinateur (CAAD), combinant méthodes immuno-histochimiques et reconstruction tridimensionnelle représente un outil original permettant l’analyse microscopique des artères et des nerfs au sein des corps caverneux. Les objectifs de ce travail étaient donc d’étudier l’innervation et la vascularisation microscopique des corps caverneux par dissection anatomique assistée par ordinateur (CAAD).Matériel et méthodes : Des coupes histologiques sériées de pénis ont été réalisées chez huit cadavres adultes masculins et sur des pièces issues de pénnectomie pour cancer à l’hôpital du kremlin-Bicêtre. Les coupes ont été traitées par des méthodes histologiques (Hématoxyline-Eosine et trichrome de Masson) et immuno-histochimiques pour détecter les fibres nerveuses (anti-S100), les fibres somatiques (anti-PMP22), les fibres adrénergiques (anti-TH), cholinergiques (anti-VAChT) et nitrergiques (anti-nNOS). Les lames ont ensuite été numérisées par un scanner de haute résolution optique et les images bidimensionnelles ont été reconstruites en trois dimensions grâce au logiciel WinSurf. Résultats: La reconstruction tridimensionnelle des coupes histologiques immuno-marquées a permis de décrire l’innervation et la vascularisation des corps caverneux du pénis. Les artères et les nerfs du pénis sont très largement anastomosés entre eux.Les anastomoses entre les artères caverneuses et les artères urétrales se font en dehors de l’albuginée du corps spongieux d’où le terme de « shunts caverno-urétraux » utilisé dans ce travail pour qualifier ces vaisseaux anastomotiques.La vascularisation et l’innervation permettent de distinguer deux compartiments anatomiques distincts au niveau du pénis : une partie proximale (les 2/3 du pénis) autonome dont les artères et les nerfs proviennent du plexus hypogastrique inférieur (supra-lévatorien), et le tiers distal somatique dont les artères et les nerfs proviennent des artères et nerfs dorsaux du pénis (infra-lévatorien).Les communications entre les systèmes autonomes et somatiques (entre le plexus hypogastrique inférieur supra-lévatorien et le nerf pudendal infra-lévatorien) existent donc à quatre niveaux : proximal, intermédiaire, à la racine du pénis et intracaverneuses. Les communications intracaverneuses sont responsables des marquages autonomes observés dans les nerfs dorsaux du pénis. Elles confèrent également aux corps caverneux une sensibilité à peu près semblable à celui du gland au cours de l’acte sexuel.Conclusion: Nos résultats montrent de très nombreuses anastomoses vasculaires et nerveuses dans les corps caverneux entre les systèmes supra et infra-lévatoriens avec 2 régions anatomiques distinctes : les 2/3 proximaux érectiles et le 1/3 distal sensitif. Ces anastomoses permettent d’espérer une certaine plasticité dans la vascularisation et l’innervation du pénis en cas de dysérection. / Introduction: The innervation and the vascularization of the corpora cavernosa of the penis are very difficult searchable by the classical anatomic dissections. Therefore, they remain not very well known. The computer-assisted anatomic dissection (CAAD), combining immunohistochemical methods and three-dimensional reconstruction is a unique tool for the microscopic analysis of the arteries and nerves in the corpora cavernosa.The objectives of this study were therefore to investigate the microscopic innervation and vascularization of the corpora cavernosa by the CAAD.Materials and methods: Serial histological sections of penis were performed in eight adult male cadavers and one piece after penectomy for cancer in the hospital of Kremlin Bicetre. The sections were processed by histological methods (hematoxylin-eosin and Masson trichrome) and immunohistochemistry to detect nerve fibers (anti-S100), somatic fibers (anti-PMP22), adrenergic fibers (anti-TH), cholinergic fibers (anti-VAChT) and nitrergic fibers (anti-nNOS). The slides were then scanned by a high resolution scanner and two-dimensional images were reconstructed in three dimensions using WinSurf software.Results: Three-dimensional reconstruction of immunolabeled histological sections allowed describing the innervation and vascularization of the corpora cavernosa of the penis. The arteries and nerves of the penis are widely anastomosed.The anastomoses between the cavernous arteries and urethral arteries are outside the tunica albuginea of the corpus spongiosum hence the term "cavernous urethral shunts".The innervation of the penis distinguishs two distinct anatomical portions: a proximal portion (2/3 of the penis) is autonomic whose arteries and nerves come from the inferior hypogastric plexus (supralevator), and the third including somatic distal nerves from the dorsal nerves of the penis (infralevator).The communications between autonomic and somatic systems (between the inferior hypogastric plexus and the pudendal nerve) exist in four levels: proximal, middle, crura of penis and intra-cavernous. The intra-cavernous communications are responsible for autonomic fibers observed in the dorsal nerves of the penis.Conclusion: Our results show a large number of vascular and nerve anastomoses in the corpora cavernosa between supra and infralevator sustems with two distinct anatomical regions: the 2/3 proximal erectile portion and 1/3 distal sensorial portion. These anastomoses provide a hope for the plasticity in the vascularization and innervation of the penis in cases of erectile dysfunction.

No description available.

L'amplitude vibratoire d'une structure mince peut être réduite grâce au couplage électromécanique qu'offrent les matériaux piézoélectriques. En termes d'amortissement passif, les shunts piézoélectriques permettent une conversion de l'énergie vibratoire en énergie électrique. La présence d'une inductance dans le circuit crée une résonance électrique due à l'échange de charges avec la capacité piézoélectrique. Ainsi, l'ajustement de la fréquence propre de ce shunt résonant à celle de la structure mécanique équivaut à la mise en œuvre d'un amortisseur à masse accordée. Cette stratégie est étendue au contrôle d'une structure multimodale par multiplication du nombre de patchs piézoélectriques. Ceux-ci sont interconnectés via un réseau électrique ayant un comportement modal approximant celui de la structure à contrôler. Ce réseau multi-résonant permet donc le contrôle simultané de plusieurs modes mécaniques. La topologie électrique adéquate est obtenue par discrétisation de la structure mécanique puis par analogie électromécanique directe. Le réseau analogue fait apparaître des inductances et des transformateurs dont le nombre et les valeurs sont choisis en fonction de la bande de fréquences à contrôler. Après s'être penché sur la conception de composants magnétique adaptés, la solution de contrôle passif est appliquée à l'amortissement de structures unidimensionnelles de type barres ou poutres. La stratégie est ensuite étendue au contrôle de plaques minces par mise en œuvre d'un réseau électrique bidimensionnel. / Structural vibrations can be reduced by benefiting from the electromechanical coupling that is offered by piezoelectric materials. In terms of passive damping, piezoelectric shunts allow converting the vibration energy into electrical energy. Adding an inductor in the circuit creates an electrical resonance due to the charge exchanges with the piezoelectric capacitance. By tuning the resonance of the shunt to the natural frequency of the mechanical structure, the equivalent of a tuned mass damper is implemented. This strategy is extended to the control of a multimodal structure by increasing the number of piezoelectric patches. These are interconnected through an electrical network offering modal properties that approximate the behavior of the structure to control. This multi-resonant network allows the simultaneous control of multiple mechanical modes. An adequate electrical topology is obtained by discretizing the mechanical structure and applying the direct electromechanical analogy. The analogous network shows inductors and transformers, whose numbers and values are chosen according to the frequency band of interest. After focusing on the design of suitable magnetic components, the passive control strategy is applied to the damping of one-dimensional structures as bars or beams. It is then extended to the control of thin plates by implementing a two-dimensional analogous network.

L'étude présentée dans ce document a pour objet l'étude de différents modes de réduction de vibrations dans les structures avec liaisons. Le premier mode étudié se base sur la dissipation d'énergie apportée par la déformation d' éléments piézoélectriques connectés à un circuit électrique adapté. Le second mode proposé se base sur la propriété de la liaison boulonnée à changer les fréquences propres d'une structure en fonction du serrage appliqué. Cette propriété est utilisée avec plusieurs lois de contrôle du serrage afin d'éviter les plages de fréquences critiques. Ensuite une étude probabiliste est effectuée pour déterminer la robustesse de la réduction de vibrations par rapport à la variation de certains paramètres du modèle. Cette étude de robustesse est effectuée à travers des méthodes stochastiques non-intrusives, parmi lesquelles une méthode originale proposée. Elle permet une réduction de la taille du modèle stochastique à résoudre, ce qui réduit très considérablement le temps de calcul sans perte de qualité significative. / The study presented in this thesis aims to explore other ways of vibration reduction in structures with bolted connections. The first way studied is based on the energy dissipation provided by the deformation of piezoelectric elements connected to an adapted electric circuit. The proposed second way is based on the property of the bolted joint of changing the natural frequencies of a structure according to the applied tightening force. This property is used via several control laws to avoid vibration on critical frequency ranges.Thereafter a probabilistic study is made to determine the robustness of the vibration reduction in relation to a variation of some model parameters. The robustness study is done through non-intrusive stochastic methods, among them a dedicated method that we propose. A stochastic model reduction is allowed which reduces dramatically the computation time without losing quality of stochastic results.

O uso de materiais piezelétricos no desenvolvimento de dispositivos para o aproveitamento de energia provinda de vibrações mecânicas, Energy Harvesting, tem sido largamente estudado na última década. Materiais piezelétricos podem ser encontrados na forma de finas camadas ou pastilhas, sendo facilmente integradas a estruturas sem aumento significativo de massa. A conversão de energia mecânica em energia elétrica se dá graças ao acoplamento eletromecânico dos materiais piezelétricos. A maioria das publicações encontradas na literatura exploram o uso de dispositivos eletromecânicos ressonantes, sintonizados na frequência de operação da estrutura, maximizando assim, a energia elétrica de saída dada uma certa condição de operação. O desempenho desses dispositivos ressonantes para coletar e armazenar energia é altamente dependente da adequada sintonização da sua frequência de ressonância com a frequência de operação do sistema/estrutura. Este trabalho apresenta o projeto, otimização e análise de incertezas de um dispositivo coletor/armazenador de energia que consiste em uma placa sob duas condições de contorno, engastada-livre (EL) e deslizante-livre (DL), com massa sísmica e materiais piezelétricos conectados a um circuito shunt. Um modelo em elementos finitos de placa laminada piezelétrica conectada a circuitos R e RL é utilizado combinando as teorias de camada equivalente e deformação de cisalhamento de primeira ordem. A disposição/quantidade de material piezelétrico bem como a massa sísmica acoplados à estrutura foram otimizadas utilizando-se um Algoritmo Genético, levando em conta análises mecânica (modelo mecânico, geometria, peso) e elétrica (modelo elétrico, circuito armazenador). Além disso, o efeito de incertezas dos parâmetros dielétrico e piezelétrico do transdutor, e da indutância elétrica ligada em série ao circuito coletor/armazenador de energia foi estudado. Os resultados indicam que a inclusão de uma indutância sintética ao circuito pode melhorar a coleta de energia em uma banda de frequência e, ainda, que a otimização geométrica pode reduzir a quantidade de material piezelétrico sem no entanto diminuir significativamente a energia gerada. / The use of piezoelectric materials in the development of devices to harvest energy from mechanical vibrations (Energy Harvesting) has been widely studied in the last decade. Piezoelectric materials can be found in the form of thin layers or patches easily integrated into structures without significant mass increase. The conversion of mechanical energy into electric power is provided by the electromechanical coupling of piezoelectric materials. Most publications in the literature explore the use of resonant electromechanical devices, tuned to the operating frequency of the host structure, thus maximizing the power output given a certain operating condition. The performance of these resonant devices to harvest and store energy is highly dependent on the proper tuning of its resonance frequency with the operation frequency of the system/structure. This work presents a design, optimization and uncertainty analysis of energy harvester device consisting of a plate with tip mass and piezoelectric materials connected to shunt circuits. Two boundary conditions are used for the plate, cantilever (EL) and sliding-free (DL). A coupled finite element model with R and RL circuits, combining equivalent single layer and first order shear deformation theories, was used. The distribution and volume of piezoelectric material and the tip mass coupled to the structure were optimized using a Genetic Algorithm, accounting for both mechanical (mechanical model, geometry, weight) and electric (electric model, storer circuit) analyses. Furthermore, the effect of uncertainties of transducer dielectric and piezoelectric constants and electric inductance connected in series with harvesting circuit was studied. The results indicate that the inclusion of a synthetic inductance can improve energy harvesting performance over a frequency range and also that the geometric optimization may reduce the piezoelectric material volume without diminishing significantly the harvested energy.

Esta tese apresenta uma análise numérica do controle de vibrações estruturais através de cerâmicas piezelétricas em extensão conectadas a circuitos ativo-passivos compostos por resistência, indutância e fonte de tensão. Para tal, um modelo de elementos finitos de vigas sanduíche com três camadas elásticas e/ou piezelétricas foi desenvolvido. Realizou-se também uma modelagem dos componentes do circuito elétrico e seu acoplamento à estrutura gerando assim uma equação de movimento acoplada para a estrutura com elementos piezelétricos conectados aos circuitos elétricos. Uma análise harmônica das equações obtidas foi realizada para se obter uma avaliação preliminar dos efeitos causados pelos componentes elétricos do circuito na estrutura. Observou-se que os elementos passivos do circuito, resistência e indutância, tem não somente um efeito de absorvedor dinâmico de vibrações mas, também, promovem uma amplificação da autoridade de controle no caso de se atuar através da fonte de tensão. Usando a metodologia tradicional de projeto de absorvedores dinâmicos de vibrações, derivou-se expressões para os valores de resistência e indutância de modo a maximizar o desempenho passivo do sistema. Uma análise do efeito de incertezas das constantes piezelétricas e dielétricas da cerâmica piezelétrica considerada e dos componentes de resistência e indutância do circuito elétrico no desempenho do controle passivo e ativo-passivo de estrutura tipo viga cantilever foi realizada. O objetivo desta análise foi quantificar robustez e sensibilidade do controle proposto. Em sequida, um estudo de otimização dos valores de resistência e indutância do circuito elétrico em função da tensão elétrica de controle máxima a ser aplicada em uma placa com diversos atuadores piezelétricos foi realizado. Finalmente e também para a estrutura tipo placa, uma análise de incertezas da rigidez da cola na interface entre estrutura e atuadores piezelétricos e seus efeitos no desempenho do controle passivo e ativo-passivo foi realizada. / This work presents a numerical analysis of the structural vibration control using piezoelectric materials in extension mode connected to active-passive electric circuits composed of resistance, inductance and voltage source. For that, a finite element model for sandwich beams with three elastic or piezoelectric layers was developed. A modeling of the electric circuit dynamics and its coupling to the structure with piezoelectric elements was also done. A harmonic analysis of the resulting equations was performed to yield a preliminary evaluation of the effects caused by the electric circuit components on the structure. It was observed that the passive circuit components not only lead to a dynamic vibration absorber effect but also to an amplification of the control authority in case of actuation using the voltage source. Using the standard methodology for the design of dynamic vibration absorbers, expressions were derived for the resistance and inductance values that optimize the passive vibration control performance of the system. An analysis of the effect of uncertainties of piezoelectric and dielectric constants of piezoelectric ceramic and resistance and inductance components of the shunt circuit on the passive and active-passive control performance for a cantilever beam structure was performed. The objective of this analysis was to quantify robustness and sensitivity of the proposed control. Then, an optimization study of the values of resistance and inductance of the shunt circuit as a function of the maximum control voltage to be applied on a plate with several piezoelectric actuators was performed. Finally and also for the plate structure, an analysis of uncertainties in the stiffness of the adhesive interface between structure and piezoelectric actuators and their effects on the performance of passive control and active-passive was performed.

Two unspecific peroxygenases (UPO, EC 1.11.2.1) from the basidiomycetous fungi Marasmius rotula and Marasmius wettsteinii oxidized steroids with hydroxyacetyl and hydroxyl functionalities at C17 - such as cortisone, Reichstein's substance S and prednisone - via stepwise oxygenation and final fission of the side chain. The sequential oxidation started with the hydroxylation of the terminal carbon (C21) leading to a stable geminal alcohol (e.g. cortisone 21-gem-diol) and proceeded via a second oxygenation resulting in the corresponding α-ketocarboxylic acid (e.g. cortisone 21-oic acid). The latter decomposed under formation of adrenosterone (4-androstene-3,11,17-trione) as well as formic acid and carbonic acid (that is in equilibrium with carbon dioxide); fission products comprising two carbon atoms such as glycolic acid or glyoxylic acid were not detected. Protein models based on the crystal structure data of MroUPO (Marasmius rotula unspecific peroxygenase) revealed that the bulky cortisone molecule suitably fits into the enzyme's access channel, which enables the heme iron to come in close contact to the carbons (C21, C20) of the steroidal side chain. ICP-MS analysis of purified MroUPO confirmed the presence of magnesium supposedly stabilizing the porphyrin ring system.

Zusammenfassung Fanny Schnauß Volumetrie der Leber aus Spiral-CT-Datensätzen von 43 Hunden mit Portosystemischem Shunt Klinik für Kleintiere der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im April 2022 83 Seiten, 34 Abbildungen, 13 Tabellen, 197 Literaturangaben, 7 Seiten Anhang Schlüsselwörter: Portosystemischer Shunt, Hund, Leber, Computertomographie, Lebervolumina, Mikrohepatie, Volumetrie Einleitung: Portosystemische Shunts (PSS) sind Gefäßanomalien, welche Blut des portalen Gefäßsystems unter Umgehung der Leber in den systemischen Kreislauf leiten. Die resultierende Minderdurchblutung der Leber führt u. a. zu einem Mangel an Wachstumsfaktoren und folglich zu einer Mikrohepatie. In der vorliegenden Arbeit wurden computertomographische (CT) Daten zur Bestimmung präziser Lebervolumina genutzt. Dies ermöglicht einen direkten Vergleich der Lebergrößen von Hunden mit PSS und ohne (Referenzgruppen). Ziele der Untersuchung: Es wurden folgende Zielstellungen bearbeitet: • Bestimmung der Präzision und Genauigkeit der Messwerte aus den CT-Daten (ex vivo Untersuchung). • Vergleich der Lebervolumina der Shunt-Patienten und der verschiedenen Subtypen mit denen der Referenzgruppen (ohne PSS, s.u.) • Die Normierung der Lebervolumina erfolgte anhand des Körpergewichts (BW), des metabolischen Körpergewichts (mBW), der Querschnittsfläche der Aorta (AAo) sowie der Querschnittsfläche des Rückenmarkkanals (AMc). Diese Normierungsmethoden wurden zur statistischen Signifikanzanalyse herangezogen und auf ihre Aussagekraft bewertet. • Analyse des präoperativen Lebervolumens als möglicher prospektiver Indikator für den Operationsverlauf sowie für den Grad der chirurgischen Einengung des Shunts. • Eruierung der postoperativen Zunahme des Lebervolumens. Tiere, Material und Methoden: Die Studie umfasst 43 Patienten mit PSS der Klinik für Kleintiere der Universität Leipzig aus den Jahren 2006 bis 2015. Als Referenzgruppe dienten 22 Hunde ohne PSS. Diese Referenzgruppe konnte weiterführend in unbestätigte Verdachtsfälle von PSS (10 Hunde) und Fälle ohne Hepatopathie (12 Hunde) unterteilt werden. Anhand der CT-Datensätze wurden retrospektiv die Lebervolumina der Tiere mittels Segmentierung und Volume-Rendering gemessen. Bei sechs Hunden mit PSS existieren Daten einer Folgeuntersuchung nach chirurgischer Versorgung, wodurch deren prä- und postoperative Lebervolumina gegenübergestellt werden konnten. In einer ex vivo Studie wurden zur Kontrolle der Messgenauigkeit der angewandten Methode sechs Lebern von Schlachtschweinen in unterschiedlichen Umgebungen (Luft, Wasser, Milch) einer CT unterzogen, anschließend deren Volumina mittels Wasserverdrängung im Wasserbad bestimmt und die Werte verglichen. Statistische Signifikanzprüfungen zwischen den unabhängigen Datengruppen erfolgten mittels Wilcoxon-Mann-Whitney-U-Test (keine Normalverteilung). Für die Prüfung auf signifikante Veränderungen der Messwerte vor und nach erfolgter Operation (verbundene Stichproben) wurde der Wilcoxon-Test verwendet (keine Normalverteilung). Ergebnisse: Es zeigten sich in allen vier Normierungen signifikant (p < 0,001) kleinere Lebervolumina für die 43 Hunde mit PSS im Vergleich zu den 22 Referenztieren (Normierung zum BW: 19,3 cm³/kg vs. 24,9 cm³/kg; mBW: 26,2 cm³/kg0,75 vs. 51,3 cm³/kg0,75; AAo: 2,6 cm vs. 4,6 cm; AMc: 2,6 cm vs. 7,5 cm). Beide Untergruppen unterschieden sich ebenfalls signifikant (jeweils p < 0,001) von der Gruppe der PSS Patienten. Keine signifikanten Unterschiede zeigten sich allerdings beim Vergleich der Hunde mit kongenitalem vs. erworbenem PSS, intra- (inPSS) vs. extrahepatischem Shunt (exPSS), rechtsseitigem vs. zentralem intrahepatischen PSS, den Subtypen der extrahepatischen PSS (portocavaler vs. Portophrenico- vs. Portoazygos-Shunt) und den Subtypen der portocavalen Shunts (gastroduodenal vs. splenocaval). Entgegen der Erwartung zeigten sich keine signifikanten Unterschiede der präoperativen Lebervolumina zwischen den Patienten bei denen in der ersten Operation (a) eine vollständige Ligatur des Shunts möglich war zu denen, die nur eingeengt werden konnten (b). Im Fall von 6 Patienten konnten prä- und postoperative CT- Aufnahmen verglichen werden. Nach einer medianen Zeitdifferenz von 72 Tagen zwischen den CT-Untersuchungen betrug die Volumenzunahme der Lebern 46,9 % (bzgl. der nicht nach Merkmalen normierten Lebervolumina). Zur Überprüfung der Richtigkeit des gewählten Analyseansatzes wurde in der ex vivo-Studie die mittlere Abweichung der Messwerte mit 5,1 ± 2,2 % bestimmt (CT-Daten vs. Wasserverdrängung der Schweinelebern). Die dreifachen Messungen ergeben eine mittlere Abweichung von nur 1,0 % (Präzision). Schlussfolgerungen: Die Messergebnisse der vorliegenden Studie zeigen klar auf, dass die Lebervolumina der Shunt-Patienten signifikant kleiner als die der Referenzgruppen ohne PSS sind. Diese signifikanten Unterschiede sind in allen Normierungen ersichtlich (jeweils p < 0,001). Allerdings ergaben sich keine signifikanten Unterschiede zwischen den verschiedenen Untergruppen der PSS-Patienten. Zur Vergleichbarkeit der Zunahme der Lebervolumina post OP erwiesen sich die Normierungen über die Querschnittsfläche der Aorta sowie über die Querschnittsfläche des Rückenmarkkanals als besonders geeignet, da diese weniger abhängig von den postoperativen metabolischen Veränderungen sind. Die Daten zeigen, dass das präoperative Lebervolumen ein insuffizienter Prädiktor sowohl für den Operationsverlauf als auch den Grad der möglichen Einengung des Shunt-Gefäßes in der Erst-OP ist. Das Lebervolumen nach chirurgischer Einengung des Shunts nahm durchschnittlich um 46,9 % zu, erreichte jedoch in dem betrachteten Zeitraum in keiner der Normierung das mediane Volumen der Patienten ohne Shunt.:Inhaltsverzeichnis 1. Einleitung 2. Literaturübersicht 2.1 Funktion, Anatomie und Gefäßsystem der Leber 2.2 Pfortaderkreislauf 2.3 Ductus venosus (Ductus Arantii) 2.4 Portosystemischer Shunt 2.5 Kongenitaler portosystemischer Shunt 2.5.1 Pathogenese und Pathophysiologie 2.5.2 Ätiologie und Prädispositionen 2.5.3 Extrahepatischer Portosystemischer Shunt 2.5.4 Intrahepatischer portosystemischer Shunt 2.6 Erworbener portosystemischer Shunt 2.7 Diagnostik des portosystemischen Shunts 2.7.1 Anamnese und klinische Symptome 2.7.2 Hepatoenzephales Syndrom 2.8 Bildgebende Diagnostik des portosystemischen Shunts 2.8.1 Sonographie 2.8.2 Projektionsradiographie 2.8.3 Computertomographie 2.8.3.1 Nativ-CT und Kontrastmittelphasen der Leber 2.8.3.2 Dynamische Computertomographie 2.8.3.3 Segmentierung und Volume Rendering/Volumendarstellung 2.8.3.4 Leber-Volumetrie 2.8.3.5 Volume-Rendering 2.9 Therapie und Prognose des portosystemischen Shunts 3. Tiere, Material und Methoden 3.1 Patienten 3.2 Anästhesieprotokoll 3.3 Computertomographische Untersuchung 3.4 Auswertung der Datensätze und Volumetrie 3.5 Referenzmessung zur Bestimmung der Messgenauigkeit 3.6 Statistische Analyse 4. Ergebnisse 4.1 Getrennte Betrachtung der beiden Referenzgruppen 4.2 Vergleich aller Shunt-Patienten mit den Referenzgruppen 4.3 Klassifizierung der Untergruppen 4.3.1 Kongenitaler und erworbener portosystemischer Shunt 4.3.2 Extrahepatischer und intrahepatischer portosystemischer Shunt 4.3.3 Vergleich der Patienten nach dem Grad der Ligatur in der Erst-OP 4.4 Bestimmung des Lebervolumens nach erfolgter Erst-Operation 4.5 Referenzmessung zur Bestimmung der Messgenauigkeit 5. Diskussion 5.1 Messmethoden, Fehlerquellen 5.2 Normierungsmethoden 5.3 Vergleich der Lebervolumina der Hunde mit PSS und beider RG 5.4 Evaluation der verschiedenen Shunt-Typen 5.5 Zunahme des Lebervolumens nach erfolgter Erst-Operation 5.6 Vollständiger oder unvollständiger Verschluss in der ersten OP 5.7 Rasse, Geschlecht, Alter und Gewicht der zu vergleichenden Gruppen 5.8 Klinische Schlussfolgerungen 6. Zusammenfassung 7. Summary 8. Literaturverzeichnis 9. Anhang 9.1 Abbildungsverzeichnis 9.2 Tabellenverzeichnis 9.3 Anhang: weitere Abbildungen und Tabellen / Summary Fanny Schnauß Liver volumetry from spiral CT datasets of 43 dogs with portosystemic shunt Department for Small Animals, Faculty of Veterinary Medicine, University of Leipzig Submitted in April 2022 83 pages, 34 figures, 13 tables, 197 references, 7 pages appendices Key words: portosystemic shunt, dog, liver, computed tomography, liver volume, microhepatia, volumetry Introduction: Portosystemic shunts (PSS) are vascular anomalies that divert blood from the portal vasculature into the systemic circulation, bypassing the liver. This results in a reduced blood supply to the liver leading, for instance, to a lack of growth factors and consequently to microhepatia. In the present work, computed tomography (CT) data was used to precisely determine liver volumes enabling a comparison of liver sizes of dogs with PSS to control animals. Objectives of this study: • Determination of the precision and accuracy of the measured values from the CT data. • Comparison of the liver volumes of the shunt patients (and various subtypes) with corresponding reference groups. • The liver volumes were normalized via body weight (BW), metabolic body weight (mBW), cross-sectional area of the aorta (AAo) and cross-sectional area of the spinal canal (AMc). These normalization methods were used for statistical significance analysis and to differentiate the patient groups. • Analysis of the preoperative liver volume as a possible prospective indicator for the course of the operation as well as for the degree of surgical narrowing of the shunt. • Determination of the postoperative increase of the liver volume. Animals, material and methods: The study included 43 shunt patients from the Clinic for Small Animals at the University of Leipzig, during the years from 2006 to 2015. 22 dogs served as the reference group. The reference group could be further subdivided into unconfirmed suspected cases of PSS (10 dogs) and cases without hepatopathy (12 dogs). Using the CT data sets, the liver volumes of the animals were measured retrospectively by means of segmentation and volume rendering. For six dogs with PSS, follow-up CT examinations after surgical treatment were conducted enabling a comparison of their pre- and post-operative liver volumes. To check the measurement accuracy of the method used, six livers from slaughter pigs were subjected to a CT examination in different environments (air, water, milk). These recordings went through the same volumetric analysis process as the dogs’ livers. This procedure further enabled a direct determination of the liver volumes by means of water displacement in a water bath. Statistical significance tests between the independent data groups were carried out using the Wilcoxon-Mann-Whitney U test. The Wilcoxon test was used to test for significant changes in the measured values before and after the operation (paired samples). Results: Significantly (p<0.001) smaller liver volumes for the 43 dogs with PSS compared to the 22 reference animals were found for all four normalizations (normalization to BW: 19.3 cm³/kg vs. 24.9 cm³/kg; mBW: 26.2 cm³/kg0,75 vs. 51.3 cm³/kg0,75; AAo: 2.6 cm vs. 4.6 cm; AMc: 2.6 cm vs. 7.5 cm). Both subgroups also differed significantly (each with p<0.001) from the group of PSS patients. However, no significant differences were found when comparing dogs with congenital vs. acquired PSS, inPSS vs. exPSS, right-sided vs. central inPSS, the subtypes of exPSS (portocaval vs. portophrenico vs. portoazygos shunt) and the subtypes of portocaval shunts (gastroduodenal vs. splenocaval). Contrary to expectations, there were no significant differences in the preoperative liver volumes between the patients where (a) a complete ligation of the shunt or (b) only a partial ligation was possible during the first operation. In the case of 6 patients, pre- and postoperative CT images could be evaluated and compared. After a median time-difference of 72 days between the CT examinations, the increase in volume of the livers was 46.9 % (liver volumes without normalization). Examinations of livers from slaughter pigs enabled both CT recordings and actual volume determinations using water displacement. These ex vivo experiments yielded a mean deviation from the measured values of 5.1 ± 2.2 % (accuracy). In addition, all volume measurements of the dog livers were carried out in triplicates, which in average only deviated by 1.0 % (precision). Conclusion: The results of the present study clearly show that the liver volumes of the shunt patients are significantly smaller than those of the reference groups. These significant differences can be seen in all normalizations (p<0.001 each). However, there were no significant differences between the various subgroups of PSS patients. The normalizations over the cross-sectional area of the aorta and over the cross-sectional area of the spinal canal are particularly suitable for comparing the increase in liver volumes after surgery. The data showed that the preoperative liver volume is an insufficient predictor for the course of the operation as well as for the degree of possible narrowing of the shunt vessel in the first OP. The liver volume after surgical narrowing of the shunt increased by an average of 46.9 %, but did not reach the median volume of the patients without a shunt by the time of the follow-up CT (independent of the normalization).:Inhaltsverzeichnis 1. Einleitung 2. Literaturübersicht 2.1 Funktion, Anatomie und Gefäßsystem der Leber 2.2 Pfortaderkreislauf 2.3 Ductus venosus (Ductus Arantii) 2.4 Portosystemischer Shunt 2.5 Kongenitaler portosystemischer Shunt 2.5.1 Pathogenese und Pathophysiologie 2.5.2 Ätiologie und Prädispositionen 2.5.3 Extrahepatischer Portosystemischer Shunt 2.5.4 Intrahepatischer portosystemischer Shunt 2.6 Erworbener portosystemischer Shunt 2.7 Diagnostik des portosystemischen Shunts 2.7.1 Anamnese und klinische Symptome 2.7.2 Hepatoenzephales Syndrom 2.8 Bildgebende Diagnostik des portosystemischen Shunts 2.8.1 Sonographie 2.8.2 Projektionsradiographie 2.8.3 Computertomographie 2.8.3.1 Nativ-CT und Kontrastmittelphasen der Leber 2.8.3.2 Dynamische Computertomographie 2.8.3.3 Segmentierung und Volume Rendering/Volumendarstellung 2.8.3.4 Leber-Volumetrie 2.8.3.5 Volume-Rendering 2.9 Therapie und Prognose des portosystemischen Shunts 3. Tiere, Material und Methoden 3.1 Patienten 3.2 Anästhesieprotokoll 3.3 Computertomographische Untersuchung 3.4 Auswertung der Datensätze und Volumetrie 3.5 Referenzmessung zur Bestimmung der Messgenauigkeit 3.6 Statistische Analyse 4. Ergebnisse 4.1 Getrennte Betrachtung der beiden Referenzgruppen 4.2 Vergleich aller Shunt-Patienten mit den Referenzgruppen 4.3 Klassifizierung der Untergruppen 4.3.1 Kongenitaler und erworbener portosystemischer Shunt 4.3.2 Extrahepatischer und intrahepatischer portosystemischer Shunt 4.3.3 Vergleich der Patienten nach dem Grad der Ligatur in der Erst-OP 4.4 Bestimmung des Lebervolumens nach erfolgter Erst-Operation 4.5 Referenzmessung zur Bestimmung der Messgenauigkeit 5. Diskussion 5.1 Messmethoden, Fehlerquellen 5.2 Normierungsmethoden 5.3 Vergleich der Lebervolumina der Hunde mit PSS und beider RG 5.4 Evaluation der verschiedenen Shunt-Typen 5.5 Zunahme des Lebervolumens nach erfolgter Erst-Operation 5.6 Vollständiger oder unvollständiger Verschluss in der ersten OP 5.7 Rasse, Geschlecht, Alter und Gewicht der zu vergleichenden Gruppen 5.8 Klinische Schlussfolgerungen 6. Zusammenfassung 7. Summary 8. Literaturverzeichnis 9. Anhang 9.1 Abbildungsverzeichnis 9.2 Tabellenverzeichnis 9.3 Anhang: weitere Abbildungen und Tabellen

This research utilizes CFD to analyze blood flow through pathways representative of central shunts, commonly used as part of the Fontan procedure to treat cyanotic heart disease. In the first part of this research, a parametric study of steady, Newtonian blood flow through parabolic pathways was performed to demonstrate the effect that flow pathway curvature has on wall shear stress distribution and flow energy losses. In the second part, blood flow through two shunts obtained via biplane angiograms is simulated. Pressure boundary conditions were obtained via catheterization. Results showed that wall shear stresses were of sufficient magnitude to initiate platelet activation, a precursor for thrombus formation. Steady results utilizing time-averaged boundary conditions showed excellent agreement with the time-averaged results obtained from pulsatile simulations. For the points of interest in this research, namely wall shear stress distribution and flow energy loss, the Newtonian viscosity model was found to yield acceptable results.

Dala Energi has large-scale plans for grid development and wants to have a better understanding of their current reactive power levels along with a future prognosis based on their plans. Changes in line inductance, shunt capacitance, area and placement put Dala Energi on the path to higher charging currents and higher reactive power generation. In addition to causing concerns in their own grid, the increased reactive power generation can present challenges for the owner of the overlying grid. Transmission of reactive power upwards is not permitted in the current contract. Dala Energi’s grid is divided into 3 separate regions with a total of 19 larger substations, 12 of which are points of connection with the overlying grid. At times, 8 of the substations have transmitted reactive power upward and soon it will be all 12. Region 1, where the 20-kV grid is located, is the biggest problem-area today, with upward-transmissions of 1 to 3 MVAr quite common and a considerable increase expected. Region 3 contains more than double the underground cable as the other two areas and might have had much greater side effects from the high shunt capacitance were it not for 3 industrial customers who consume a large portion of reactive power. In the coming years, however, Region 3 is expected to have capacitive reactive power levels nearly equal to those of Region 1. The combined reactive power baseline for all regions is expected to drop by 8.24 MVAr in the coming years. The owner of the overlying grid controls Dala Energi’s 5 largest capacitor banks which have a rated capacity of 11.6 MVAr. With the entire capacity almost always connected, the upward transmission of reactive power becomes much greater. It would be very advisable to meet with the owner, discuss interaction between the two grids and examine the details of the current contract. Compensation for excessive generation of reactive power is needed and is going to be essential in the future. The short-term variation of reactive power levels is so great that the use of fixed rating shunt reactors is ill-advised, especially under the current contract. Compensation with variable shunt reactors is recommended.