Dissertations / Theses on the topic 'SCR free'

Stress-corrosion cracking of austenitic alloys in an oxygen-free carbon dioxide environment containing chloride ions was studied under static conditions. Stiffness and X-ray measurements supported results obtained from SEM photomicrographs indicating that the CT specimens loaded to a stress intensity of 22 ksi-in^.5 were not susceptible to SCC in this environment. These alloys were also evaluated for their SCC resistance in boiling MgCl₂ and NaCl solutions. Results of this study indicated that alloys containing higher nickel contents were more resistant to chloride SCC.
Master of Science

The research investigates the influence on the human body on a communication system. To understand this, the effect of hands free kit (HFK) on energy absorption in the body was investigated when operating a smart phone at 2G. Findings on the research are given in the thesis report. Also, the influence of the way in which a phone is held on a phone s received power was investigated. The result was compared to that obtained using a hand phantom acquired from SPEAG. This was to check if the hand phantom best represents the human hand when using it in experiments. The setup for the experiment was in an anechoic chamber at Loughborough University. The mobile phone transmitted in the 2G system. In further experiments carried out on the body, two antennas were attached to the body in six different orientations to receive power from a source creating a Single Input Multiple Output (SIMO) system. The antennas used were monopoles mounted on a circular ground plane. These antennas were designed and constructed with the influence of the body taken into consideration. The use of diversity techniques to improve transmission to an on-body system is investigated with the antennas on the body. For each alignment, the transmission to the on-body was compared with the transmission to the corresponding off-body (free space). Experiments for this work were carried out in three environments.

Unlike other regenerative organs such as the liver, the adult mammalian heart does not regenerate tissue lost following injury such as myocardial infarction (MI). Instead a non-contractile fibrous scar develops that in the longer term leads to the development of heart failure (HF). In contrast to the adult, neonatal mammals, including mice and man, retain potent cardiac regenerative capacities and can replace myocardium lost following injury. Understanding the mechanisms underlying scar free repair in the neonate may help in development of new approaches to reduce the impact of myocardial injury in adults. In this thesis MI was induced by coronary artery ligation in mice at post-natal day 1 (P1). Novel electrocardiogram gated high resolution cardiac ultrasound was developed to permit non-invasive confirmation of injury 1 day later and regeneration 21 days later by loss, then restoration, of contractile function. Macrophages (MФ) play important roles in organ growth and homeostasis, and are required for scar-free regeneration of the neonatal mouse heart following MI. WNTs are secreted lipophilic proteins with multiple roles in development. MФ-derived WNTs are essential for scar free tissue regeneration following injury in the kidney, liver, and gut, but their role in the heart is unknown. The primary aim of this thesis was to investigate the role of MФ, and in particular MФ-derived WNTs in determining normal growth of the myocardium from neonate to adult and also in regeneration of the neonatal heart following injury. In wild-type neonatal mouse hearts, Csf1r-expressing cells density (mostly macrophages) was consistent across all time points studied. Three populations of resident cardiac mononuclear phagocytes were identified by flow cytometry: F4/80hi, CD11blo, Ly6C-ve - F4/80lo, CD11bhi, Ly6C-ve - F4/80lo, CD11bhi, Ly6C+ve. F4/80hi, CD11blo, Ly6C-ve cells were hypothesised to correspond to yolk-sac derived mononuclear phagocytes and F4/80lo, CD11bhi, Ly6C-ve - F4/80lo, CD11bhi, Ly6C+ve to foetal liver/bone marrow derived mononuclear phagocytes. Three phases of myocardial growth were identified by ultrasound and histological techniques: hyperplastic (P2-P8, with increased Ki67 and cardiac troponin immunopositive cells), hypertrophic/reorganisation (P8-P21, with increasing cardiomyocyte size and no change in left ventricle wall thickness), and finally hypertrophic solely (P21-P42, with increasing cardiomyocyte size and left ventricle wall thickness). Average coronary vessel size was shown to decrease between P2 and P8 whilst vessel density was increased. The number of α-smooth muscle actin (αSMA) coated vessels greatly increased between P8 and P42, indicating vessel maturation. Throughout all phases cardiac systolic function was maintained at steady state. Diastolic function was however shown to mature from a foetal to an adult pattern between P2 and P8, with reversal of the E:A wave ratio on Doppler ultrasound. In mice globally deficient in MФ due to a germline knock-out of the Csf1r gene (Csf1rnull mice), both body and heart weights were decreased from P7 onwards. The number of proliferating (Ki67+ve) cardiomyocytes at P1 and P7 was unchanged in Csf1r-null mice but there was a trend towards decreased cardiomyocyte size at P7, suggesting an influence on hypertrophic rather than hyperplastic growth of the myocardium. There was also a trend for slowed vascular network maturation, with a delay in the shift from large to smaller vessels in hearts from Csf1r-null mice. In mice with MФ-directed (Csf1r-icre mediated) depletion of Porcupine (Porcn), a gene encoding an enzyme required for WNT acylation and secretion cardiac growth, vascularisation, fibrosis and function were all similar in Cre-ve and Cre+ve animals until P41, when cardiomyocyte size and cardiac systolic function were both significantly increased in Cre+ve animals. However, the underlying mechanism is unknown. In the neonatal mice, Csf1r expressing cells, mostly MФ, were identified in association with regenerating myocardium after induction of MI at P1. Flow cytometry data showed that by P7 the putative resident yolk-sac derived population had mostly disappeared from the heart and was replaced by F4/80lo cells, similar to the pattern reported in the adult. In the regenerating myocardium, Axin2 expression was increased consistent with activation of canonical Wnt signalling. Expression of Wnt5b and Fzd2 receptor, both associated with fibrosis, was significantly increased relative to age matched uninjured hearts. MФ-directed depletion of Porcn did not influence either the functional decrease at day 1 or recovery at day 21 following induction of MI at P1. Coronary re-vascularisation was also unaffected by the genotype. However, retention of intra-myocardial fibrosis (picrosirius red staining) was significantly increased in hearts at day 21 post-MI from mice with MФ-directed depletion of Porcn. MФ-derived WNTs are therefore required for scar-free wound healing in the heart, as they are in the liver and the kidney where they regulate matrix metalloproteinase activity. In summary, novel ECG-gated high-resolution in vivo ultrasound developed in this project has allowed characterisation of cardiac structure and function during early post-natal growth and following injury and regeneration in neonatal mice. The resident MФ population of the heart is established pre-natally, and may play a role in determining maturation of the developing vascular network, although this does not involve MФ-derived Wnt signalling. Following MI, the MФ population may expand from bone marrow cells and MФ accumulate around the regenerating tissue. MФ derived WNTs are not required for regeneration of the neonatal myocardium but do have a role in ensuring scar free wound healing and this merits further investigation.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In this work the relationship between two famous conceptions of existence is investigated. The first, proposed by Kant, excludes the concept of existence from the set of possible predicates or properties of objects. The second, later proposed by Frege, treats the concept of existence as a higher-level predicate, i.e., it presents this concept as a predicate of predicates rather than as a predicate of objects. A closer look at these conceptions reveals, however, that despite this similarity it would be premature to identify their conceptions, because there are differences with regard to the systems in which they are embedded as well as differences with regard to the aims that they pursue. The present work tries to show that Kant developed his conceptions of the concept of existence in an epistemological context whose aim was, as he makes clear in his opus magnum, to warrant the claim that every knowledge should have besides a conceptual element also a counterpart arising from the intuition. Frege, on the other hand, develops his conception in a basically logical context, in which the treatment of expressions is submitted to strong rigor. The aim of the present work is to compare Kant s and Frege s approaches in order to answer the question whether there are significant differences between their characterizations of the concept of existence and, if so, which ones. One important result of the present work is that the differences in their positions are consequences of some differences between the contexts in which they are developed. Another result is that their conceptions include some common theses, such as the claim that the concept of existence is not a concept that can be used to characterize an object, or the claim that existential statements constitute an odd type of judgement whose appearance in natural languages suggests an erroneous reading of them. On the other hand, however, there are significant differences between the positions advocated by Kant and Frege as, for instance, differences with regard to the possibility of deriving statements of existence from the analysis of concepts, a possibility that is categorically denied by Kant but admitted, with some qualifications, by Frege. The third important result finally is that Frege s conception of existence must be regarded as an improvement, not as a mere repetition, of Kant s conception.
Este trabalho apresenta um estudo da relação entre duas célebres abordagens do conceito de existência. A primeira, apresentada por Kant, exclui o conceito de existência do conjunto dos possíveis predicados ou propriedades de objetos. A segunda, apresentada mais tarde por Frege, trata o conceito de existência como um predicado de nível superior, i.e., apresenta o conceito como um predicado de predicados, e não como um conceito que se aplica diretamente a objetos. Apesar de ambas abordagens se parecerem muito entre si, um estudo mais aprofundado de ambas servirá para mostrar que a diferença entre os sistemas teóricos em que se inserem, bem como entre os objetivos que visavam, sugerem que seria precipitado identificá-las. Tentar-se-á mostrar, neste trabalho, que Kant desenvolve suas concepções a respeito deste conceito num contexto epistemológico, tendo em vista, como fica claro na sua opus magnum, garantir o requisito de que todo conhecimento deve ter, além do elemento conceitual, também uma contraparte advinda da intuição. Frege, por sua vez, apresenta suas teses a respeito do tema dentro de um contexto basicamente lógico, onde se fazia necessária uma rigorização do tratamento das expressões que compõem a linguagem. O objetivo do presente trabalho consiste em estudar a abordagem de cada autor separadamente, e, em seguida, comparar as duas abordagens a fim de mostrar se existem diferenças significativas entre as caracterizações que ambos deram ao conceito de existência, e, em caso positivo, mostrar quais seriam estas diferenças. Dentre os principais resultados a que se chegou, destacam-se as diferenças que as posições dos autores possuem; diferenças sugeridas pela diferenciação entre os contextos de apresentação da temática nos dois autores. Também se destaca a equivalência das teses de ambos em alguns aspectos, como por exemplo, a tese segundo a qual o conceito de existência não se encontra entre os conceitos que podem servir para caracterizar um objeto, ou a alegação de que os enunciados existenciais constituem um tipo único de juízo, cuja aparência nas linguagens naturais sugere uma leitura errônea dos mesmos. Deve-se mencionar, por outro lado, a diferença significativa de posições de Kant e Frege em outros aspectos, como no que tange à possibilidade de se derivar existência por meio de análise conceitual, possibilidade negada categoricamente por Kant e admitida, com algumas ressalvas, por Frege. Por fim, destaca-se a possibilidade de se interpretar as teses de Frege como um aperfeiçoamento, mas não como uma mera repetição, das teses de Kant.

The author makes a critical analysis of how over time it has tried to find the subject of study of Law and how it is distinguished from other beings that make up the universe. t hus the rational dimension of man has passed his ontological analysis as being in itself which makes it unique and spirit as the arrangement will be co-existential seeking protection for the same freedom he has. Finally, the author focuses on the own “freedom” of man and of which the other rights it has.
El autor hace un análisis crítico de cómo a lo largo del tiempo se ha tratado de encontrar al sujeto de estudio del Derecho y cómo este se distingue de los demás seres que conforman el universo. e s así como de la dimensión racional del ser humano se ha pasado a su análisis ontólogico como ser en sí mismo cuyo espíritu lo hace único y en tanto que ser coexistencial le procura el ordenamiento una protección por la misma libertad que posee. Finalmente el autor se centra en esa “Libertad” propia del ser humano que genera los demás derechos que posee.

Les techniques de fluorescence de molécule individuelle permettent de suivre la dynamique moléculaire et les interactions dans les processus biologiques. Maintenant, la dynamique moléculaire des protéines est principalement accompagnée du marquage fluorescent externe. Cependant, une molécule attachée peut perturber la dynamique de protéines. Heureusement, la majorité des protéines contiennent le tryptophane ou la tyrosine qui absorbent et émettent la lumière dans le domaine spectral d'UV entre 260 nm et 400 nm. Ces acides aminés ont de basses efficacités quantiques, photostabilisées dans l'UV et la section efficace d'absorption, qui gênent la détection des protéines individuelles. Afin d'atteindre la sensitivité de l'auto fluorescence UV des protéines individuelles, nous développons un microscope confocal UV à la résolution temporelle avec les lasers de 266 nm et 295 nm. Nous quantifions la sensitivité de détection et l'effet des techniques de photostabilisation sur l'autofluorescence des protéines. La spectroscopie de corrélation de fluorescence (SCF) et les mesures de time-correlated single photon counting (TCSPC) fournissent des informations quantitatives du volume de détection, de l'amélioration de fluorescence (AF), et de la photokinétique accélérée des molécules émettant à la présence et à l'absence des nanostructures d'aluminium (Al). En utilisant le p-terphenyl, nous optimisons les nanostructures plasmoniques d'Al afin d'améliorer la fluorescence. Sous certaines conditions, le confinement de la lumière et l'AF dans les structures d'Al permettent d'appliquer la plasmonique UV pour la détection des protéines individuelles de beta-galactosidase sans marquage
Single molecule fluorescence techniques enable to monitor the molecular dynamics and interactions in the biological processes. Nowadays, the molecular dynamics of proteins is principally accompanied by external fluorescent labeling. However, an attached molecule might perturb the protein dynamics. Fortunately, a vast majority of proteins contain tryptophan and tyrosine that absorb and emit light in the UV range of 260-400 nm. These intrinsically fluorescent amino acids yield limited absorption cross-section, quantum yield, and photostability in the UV range, which hampers single protein UV autofluorescence detection. In order to reach single molecule sensitivity of protein UV autofluorescence, we develop a time-resolved UV confocal microscope with 266 nm and 295 nm excitations and the detection optics in the near UV. Based on the total fluorescence time traces, we quantify the single molecule sensitivity, the effect of photostabilization techniques on the protein autofluorescence. Fluorescence correlation spectroscopy (FCS) and time-correlated single photon counting (TCSPC) measurements provide quantitative information on the detection volume, the fluorescence enhancement factors, and the accelerated photokinetics of the UV emitting molecules in the presence and absence of the aluminum (Al) nanostructures. Using p-terphenyl as a bright UV emitting molecule, we optimize the Al plasmonic nanostructures to enhance the single molecule fluorescence. Under certain conditions, the light confinement and fluorescence enhancement in the aluminum nanostructures enable to apply the UV plasmonics for the single molecule detection of label-free beta-galactosidase protein

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This study aims to analyze the relationship between thehuman will with the problem of evil from the of Augustine thought. Since your youth Augustine questioned about the problem of evil and saw in the Manichean dualism a reasonable response as a solution to the problem. After nearly a decade in Manichaeism, Aurelio Augustine moved to Rome and then Milan, where he participated in Platonic studies group. However, the contact of Augustine, in Milan, with the Catholic Bishop Ambrose led him to conversion to Catholicism and the abandonment of Manichaeism. From this, Augustine prepared your theory about evil, that relate directly to human will. In this perspective, evil is not a being, as he taught the Manichaeism, but as a result of the free will of the human being by your will stop wanting want God as supreme good for wanting a well more than himself. In this way, the desire human being deprived of God, corrupting the relationship between the divine and the human.
Este estudo visa analisar a relação entre a vontade humana com o problema do mal a partir do pensamento de Agostinho. Desde a sua juventude Aurélio Agostinho questionava-se sobre o problema do mal e viu no dualismo maniqueísta uma resposta razoável como solução para o problema. Depois de quase uma década no maniqueísmo, Agostinho mudou-se para Roma e posteriormente, Milão onde participou de grupo de estudos platônicos. Contudo, o contato de Agostinho, em Milão, com o bispo católico Ambrósio levou-o a conversão ao catolicismo e com isso o abandono do maniqueísmo. A partir disso, Agostinho elaborou sua teoria sobre o mal, a que está relacionada diretamente à vontade humana. Nessa perspectiva, o mal não é um ser, como ensinava o maniqueísmo, mas fruto da vontade livre do ser humano que, por livre vontade, deixa de querer Deus como bem supremo para querer um bem inferior ou a si mesmo. Dessa forma, pela vontade o ser humano se priva de Deus corrompendo a relação entre o divino e o humano.
São Cristóvão, SE

En Imagerie par Résonance Magnétique (IRM), l’augmentation du champ magnétique statique permet en théorie de fournir un rapport signal sur bruit accru, améliorant la qualité des images. L’objectif de l’IRM à ultra haut champ est d’atteindre une résolution spatiale suffisamment haute pour pouvoir distinguer des structures si fines qu’elles sont actuellement impossibles à visualiser de façon non-invasive. Cependant, à de telles valeurs de champs magnétiques, la longueur d’onde du rayonnement électromagnétique envoyé pour basculer les spins des protons de l’eau est du même ordre de grandeur que l’objet dont on souhaite faire l’image. Des phénomènes d’interférences sont observés, ce qui se traduit par l’inhomogénéité de ce champ radiofréquence (RF) au sein de l’objet. Ces interférences engendrent des artefacts de signal et/ou de contraste dans les images IRM, et rendent ainsi leur exploitation délicate. Il est donc crucial de fournir des solutions pour atténuer la non-uniformité de l’excitation des spins, à défaut de quoi de tels systèmes ne pourront atteindre leurs pleins potentiels. Pour obtenir des diagnostics pertinents à très haut champ, il est donc nécessaire de créer des impulsions RF homogénéisant l'excitation de l'ensemble des spins (ici du cerveau humain), optimisées pour chaque individu. Pour cela, un système de transmission parallèle (pTX) à 8 canaux a été installé au sein de notre imageur à 7 Tesla. Alors que la plupart des systèmes IRM cliniques n’utilisent qu’un seul canal d’émission, l’extension pTX permet de jouer différentes formes d’impulsions RF de concert. La somme résultante de ces interférences doit alors être optimisée pour atténuer la non-uniformité observée classiquement. L’objectif de cette thèse est donc de synthétiser ce type d’impulsions, en utilisant la pTX. Ces impulsions auront pour contrainte supplémentaire le respect des limitations internationales concernant l'exposition à des champs radiofréquence, qui induit une hausse de température dans les tissus. En ce sens, de nombreuses simulations électromagnétiques et de températures ont été réalisées en introduction de cette thèse, afin d’évaluer la relation entre les seuils recommandés d’exposition RF et l’élévation de température prédite dans les tissus. Cette thèse porte plus spécifiquement sur la conception de l’ensemble des impulsions RF refocalisantes utilisées dans des séquences IRM non-sélectives, basées sur l’écho de spin. Dans un premier temps, seule une impulsion RF a été générée, pour une application simple : l’inversion du déphasage des spins dans le plan transverse. Dans un deuxième temps, sont considérées les séquences à long train d’échos de refocalisation appliquées à l’in vivo. Ici, l’opérateur mathématique agissant sur la magnétisation, et non pas son état final comme il est fait classiquement, est optimisé. Le gain en imagerie à très haut champ est clairement visible puisque les opérations mathématiques (la rotation des spins) voulues sont réalisées avec plus de fidélité que dans le cadre des méthodes de l’état de l’art. Pour cela, la génération de ces impulsions RF combine une méthode d’excitation des spins avec navigation dans l’espace de Fourier, les kT-points, et un algorithme d’optimisation, appelé Gradient Ascent Pulse Engineering (GRAPE), utilisant le contrôle optimal. Cette conception est rapide grâce à des calculs analytiques plus directs que des méthodes de différences finies. La prise en compte d’un grand nombre de paramètres nécessite l’usage de GPUs (Graphics Processing Units) pour atteindre des temps de calcul compatibles avec un examen clinique. Cette méthode de conception d’impulsions RF a été validée expérimentalement sur l’imageur 7 Tesla de NeuroSpin, sur une cohorte de volontaires sains
In Magnetic Resonance Imaging (MRI), the increase of the static magnetic field strength is used to provide in theory a higher signal-to-noise ratio, thereby improving the overall image quality. The purpose of ultra-high-field MRI is to achieve a spatial image resolution sufficiently high to be able to distinguish structures so fine that they are currently impossible to view in a non-invasive manner. However, at such static magnetic fields strengths, the wavelength of the electromagnetic waves sent to flip the water proton spins is of the same order of magnitude than the scanned object. Interference wave phenomena are then observed, which are caused by the radiofrequency (RF) field inhomogeneity within the object. These generate signal and/or contrast artifacts in MR images, making their exploitation difficult, if not impossible, in certain areas of the body. It is therefore crucial to provide solutions to mitigate the non-uniformity of the spins excitation. Failing this, these imaging systems with very high fields will not reach their full potential.For relevant high field clinical diagnosis, it is therefore necessary to create RF pulses homogenizing the excitation of all spins (here of the human brain), and optimized for each individual to be imaged. For this, an 8-channel parallel transmission system (pTX) was installed in our 7 Tesla scanner. While most clinical MRI systems only use a single transmission channel, the pTX extension allows to simultaneously playing various forms of RF pulses on all channels. The resulting sum of the interference must be optimized in order to reduce the non-uniformity typically seen.The objective of this thesis is to synthesize this type of tailored RF pulses, using parallel transmission. These pulses will have as an additional constraint the compliance with the international exposure limits for radiofrequency exposure, which induces a temperature rise in the tissue. In this sense, many electromagnetic and temperature simulations were carried out as an introduction of this thesis, in order to assess the relationship between the recommended RF exposure limits and the temperature rise actually predicted in tissues.This thesis focuses specifically on the design of all RF refocusing pulses used in non-selective MRI sequences based on the spin-echo. Initially, only one RF pulse was generated for a simple application: the reversal of spin dephasing in the transverse plane, as part of a classic spin echo sequence. In a second time, sequences with very long refocusing echo train applied to in vivo imaging are considered. In all cases, the mathematical operator acting on the magnetization, and not its final state as is done conventionally, is optimized. The gain in high field imaging is clearly visible, as the necessary mathematical operations (that is to say, the rotation of the spins) are performed with a much greater fidelity than with the methods of the state of the art. For this, the generation of RF pulses is combining a k-space-based spin excitation method, the kT-points, and an optimization algorithm, called Gradient Ascent Pulse Engineering (GRAPE), using optimal control.This design is relatively fast thanks to analytical calculations rather than finite difference methods. The inclusion of a large number of parameters requires the use of GPUs (Graphics Processing Units) to achieve computation times compatible with clinical examinations. This method of designing RF pulses has been experimentally validated successfully on the NeuroSpin 7 Tesla scanner, with a cohort of healthy volunteers. An imaging protocol was developed to assess the image quality improvement using these RF pulses compared to typically used non-optimized RF pulses. All methodological developments made during this thesis have contributed to improve the performance of ultra-high-field MRI in NeuroSpin, while increasing the number of MRI sequences compatible with parallel transmission

The rapid growth in global mobile phone users has resulted in an ever-increasing demand for bandwidth and enhanced quality-of-service (QoS). Several consortia comprising major international mobile operators, infrastructure manufacturers, and academic institutions are working to develop the next generation wireless communication systems fifth generation (5G) - to support high data rates and increased QoS. 5G systems are also expected to represent a greener alternative for communication systems, which is important because power consumption from the information and communication technology (ICT) sector is forecast to increase significantly by 2030. The deployment of ultra-dense heterogeneous small cell networks (SCNs) is expected to play a major role in meeting the explosive growth of user traffic demand in 5G wireless communication systems. However, while the concept of small cells in heterogeneous networks (HetNets) largely addresses the bandwidth scarcity problem, unless otherwise carefully managed, a large number of uncoordinated and lightly loaded SCNs will significantly increase the access network power consumption, contrary to the green communication target of 5G systems. In addition, to cater for the huge volumes of traffic, the backhaul network power consumption will also increase. This thesis addresses the research challenges facing 5G systems in regard to energy efficiency and QoS. The thesis examines ways to reduce power consumption in access networks, how to design green backhauling solutions, how to develop synergy between wired and wireless backhauling options, and how to increase energy efficiency in a weather-dependent backhaul network without hindering network QoS. Different system models and solution techniques are investigated in order to successfully minimize overall power consumption in 5G HetNets while maintaining network QoS. The thesis contributes as follows: first, an energy-efficient resource management system is introduced to minimize access network power consumption; second, two green backhauling solutions, one for wired optical backhaul and the other for wireless millimeter wave (mmWave) backhaul, are presented; third, a synergy is developed between two energy-efficient backhauling solutions to reduce power consumption; fourth, the impacts of SCN topology and mmWave spectrum are presented; and finally, a hybrid free-space optics (FSO)/mmWave channel model is introduced to minimize power consumption for weather-dependent channels. Each phase of the research listed above also investigates the network QoS, i.e., average delay and jitter for 5G HetNets. The research presented in this thesis therefore contributes new knowledge in energy efficiency and QoS for next generation wireless communication networks and makes important contributions to this field by investigating different system models and proposing solutions to significant issues.

Scar-free wound healing and regeneration are uncommon phenomena permitting the near complete restoration of damaged tissues, organs and structures. Although rare in mammals, many lizards are able to undergo scarless healing and regeneration following loss of the tail. This study investigated the spontaneous and intrinsic capacity of the leopard gecko (Eublepharis macularius) tail to undergo scar-free wound healing and regeneration following two different forms of tail loss: autotomy, a voluntary and evolved mechanism of tail shedding at fracture planes; and surgical amputation, involuntary loss of the tail outside the fracture planes. Furthermore, I investigated the ability of the regenerate tail to regenerate by amputating a regenerate tail (previously lost by autotomy). To investigate these phenomena I imaged wound healing and regenereating tails daily (following autotomy and amputation) to document gross morphological changes. I used histochemistry to document tissue structure and immunohistochemistry to determine the tissue/cellular location of my five proteins of interest (PCNA, MMP-9, WE6, α-sma, TGF-β3). Each of these proteins of interest has been previously documented during wound healing and/or regeneration in other wound healing/regeneration model organisms (e.g. mice, urodeles, lizards, zebrafish). Scar-free wound healing and regeneration occurred following autotomy, amputation of the original tail and amputation of the regenerate tail, indicating that the leopard gecko tail has an instrinsic scar-free wound healing and regenerative capacity that is independent of the mode of tail loss (autotomy or amputation). Furthermore immunohistochemistry revealed a conserved sequence and location of the expression of the five proteins of interest following both forms of tail loss. These results provide the basis for further studies investigating scar-free wound healing and regeneration in a novel amniote model, the leopard gecko.
NSERC

碩士
國立成功大學
電機工程學系
102
This thesis presents a 12-bit 80-MS/s low power pipelined successive approximation register (SAR) analog-to-digital converter (ADC) with loading-free architecture. The basic idea of this work is manipulating the capacitor array of the second-stage SAR ADC to serve as the feedback capacitor of the first stage amplifier during its amplification mode. In addition to the saving in the occupied area of the total capacitor, such an arrangement reduces the power consumption of the used high performance operation amplifier as well, resulting in a low-power and compact ADC. Additionally, the fixed-window function technique is adopted to cut the power consumption and tolerate non-idealities in the first-stage SAR ADC, including the comparator’s erroneous judgments incurred by incomplete settling behavior during the capacitor array switching, large INL/DNL errors due to the capacitor mismatch, and missing codes induced by comparator offset. Moreover, the direct switching technique is also utilized to reduce the critical path delay between the digital control logic and switching buffers. This proof-of-concept ADC is fabricated in TSMC standard low-power 90-nm 1P9M CMOS process with the active area of only 0.117 mm2. The measured peak SNDR is 55.98 dB and effective resolution bandwidth (ERBW) is 35 MHz. The total power consumption is 2.72 mW.

碩士
國立中山大學
資訊工程學系研究所
102
This delay locked loop uses TSMC 90nm process. It uses the shift-counting type successive approximation register to control the digital delay line, which can solve the problem of harmonic lock. The part of delay line uses a complementary way to improve the range of lockable and using coarse and fine way to improve the resolution of delay. This delay locked loop uses 10-bit successive approximation register to achieve the fast locking. In addition, the locking range is from 100 MHz to 1 GHz. The supply voltage is 1.2V. The delay resolution is about 4 ps. The power is 0.38 mW at 100 MHz and 0.9 mW at 1 GHz. The jitter is 8.8 ps at 100 MHz and 2.6 ps at 1 GHz. The lock time is 40 clock cycles at 100MHz and 24 clock cycles at1 GHz.

碩士
國立臺灣科技大學
電子工程系
106
For 16-bit successive approximation register (SAR) analog-to-digital converters (ADCs), noise and linearity are two major challenges for chip implementation. In this work, without the oversampling and noise-shaping techniques, I use several circuit design skills to meet the noise specification. For the linearity, it’s mainly affected by the capacitor mismatch. In this thesis, two techniques are presented to improve the ADC linearity. One is the level-two capacitor-swapping technique, and the other is the fast-binary-window DAC switching scheme. For the first two MSB capacitor switching, the level-two capacitor-swapping utilizes the swapping mechanism to transform the distortion into noise for better SFDR. The fast-binary-window DAC switching technique changes the SAR ADC’s conventional switching method to improve SNDR by reducing unnecessary capacitor switching. A 16-bit 1-MS/s calibration-free SAR ADC was implemented in TSMC 0.18μm CMOS. This ADC chip occupies die area of 0.52 mm2. It consumes 1.54 mW from a 1.8V supply. At a 1-kHz input frequency, the measured DNL is -0.7/1.3 LSB. The measured INL is -3.1/3.3 LSB. The measured SNDR and SFDR are 76.3 dB and 102 dB, respectively. This leads to a Schreier FOM of 161.4 dB.

This research focuses on anoxic ammonium oxidation (anammox). The anammox process for treating high ammonium and low organic carbon wastewater can reduce operational costs to a greater extent than the conventional autotrophic/heterotrophic treatment process can. The process has been widely researched because of its potential economic benefits. However, during long-term reactor operation, sudden reductions of nitrogen removal rates have been reported; maximum nitrogen removal rates in different reactor configurations could not approach values predicted based on mathematical modeling; and the crucial stability parameter, such as nitrite, did not have defined threshold concentration. It was hypothesised that free ammonia (FA) increase is the precursor of the instability of the anammox reactor. If it is true that nitrite up to about 200 mg N/L should stimulate nitrogen removal rate inside of the anammox reactor, when FA is kept below the inhibition threshold concentration. The research presented in the thesis argues that FA plays a larger role than has been previously considered in the instability of the anammox reactor. This study found FA inhibited nitrogen removal rates (NRR) at concentrations exceeding 2 mg N/L. In the pH range 7 to 8, the decrease in anammox activity was independent of pH and related only to the concentration of FA. Nitrite concentrations of up to 200 mg N/L did not negatively affect nitrogen removal rate. This study further found that low nitrite provided stable anammox reactor performance, but that high nitrite was not necessarily the cause for reactor destabilization. During the research high nitrogen removal rate was achieved when low FA was provided. During regular reactor operation at pH 6.5, the NRR at about 6.2 g N/Ld was archived. This value was never achieved before till this study was conducted. Conducted research showed controlling FA at low level is required to approach high rates in anammox reactors. Achieving high rates in anammox reactors allow significant reduction in reactor volume which saves resources. Further studies will be required to identify the FA effect on different microbial interactions, and that may provide more in-depth understanding of the nitrite and FA effect than observations based on NRR alone.

碩士
國立成功大學
電機工程學系
105
A single-channel 8-bit 400-MS/s successive-approximation register (SAR) analog-to-digital converter (ADC) in 90-nm CMOS process is presented in this thesis. We propose a hybrid architecture for high-speed SAR ADC without a complex calibration engine. The operation speed is enhanced by adopting the loop-unrolled technique in the coarse conversions. Considering the mismatch between coarse and fine conversions, we adopt the non-binary search scheme with redundancy to maintain the overall performance. Moreover, two circuit techniques are proposed to increase the operation speed in the fine conversions. Firstly, a pre-amplifier-only comparator is proposed to shorten the critical timing path in the fine conversions. It significantly reduces the comparator reset time. Secondly, we propose a high-gain dynamic pre-amplifier to mitigate the offset mismatches among the latches for the requirement of the overall accuracy. With the above-mentioned techniques, it leads to a calibration-free design. The proof-of-concept prototype was fabricated in a TSMC 90-nm CMOS technology. The core area occupies 0.0276 mm2. At a supply voltage of 1.2-V and sampling rate of 400-MS/s, the power consumption of the SAR ADC is 3.198 mW. The peak ENOB is 7.15 bits without complex calibration circuit. It achieves a figure of merit (FoM) of 56.29 fJ/conversion-step.

The regulatory standards set by food authorities globally for probiotic foods such as Cheddar cheese makes it essential to have reliable enumeration media that will accurately monitor the survival of probiotic bacteria over the shelf life of Cheddar cheese. This study therefore investigated various selective and differential media for reliable enumeration of Lactobacillus acidophilus, Bifidobacterium spp., starter lactic acid bacteria (SLAB) and non-starter lactic acid bacteria (NSALB) from Cheddar cheese using pure cultures and commercial probiotic Cheddar cheese. All media showed variation in counts and selectivity. Some reported selective media failed to inhibit SLAB and NSLAB. The media that were reliable and also gave good recovery were, Reinforced Clostridium Agar with Bromocresol green and Clindamycin (RCABC), which was selective for L. acidophilus spp. and Reinforced Clostridium Agar with Aniline blue and Dicloxacillin (RCAAD), which was differential for Bifidobacterium spp. and SLAB. Reinforced Clostridium Agar with Bromocresol green and Vancomycin (RCABV) was found suitable for NSLAB. Additionally, an enzyme based colorimetric assay was modified successfully and used as a confirmatory test to check the presence of bifidobacterial colonies on enumeration media. Six batches of probiotic Cheddar cheese were manufactured with the incorporation of LAFTI L10 (L. acidophilus) and LAFTI B94 (B. lactis). The survival of probiotic bacteria, SLAB and NSLAB were monitored over a six-month ripening period using the selected media. The survival of free probiotic bacteria throughout the ripening process decreased consistently in all the six batches. In order to enhance the survival of probiotic bacteria, the effect of microencapsulation on the viability of LAFTI L10 and LAFTI B94 in Cheddar cheese was studied. Six batches of Cheddar cheese were manufactured with the incorporation of alginate-starch encapsulated and free cells of LAFTI L10 and LAFTI B94. The survival of both the encapsulated and free probiotic bacteria was studied over a six month ripening period. The survival of encapsulated LAFTI L10 and LAFTI B94 (107 cfu/g) was found to be significantly better than that of free bacteria (105 cfu/g) at the end of six months of ripening period in Cheddar cheese.

Eastern grey kangaroos (Macropus giganteus) are one of Australia’s most iconic species. An increase in watering sites and urban development have dramatically influenced the species range and abundance. Current knowledge of group structure, dispersal and behaviour of eastern grey kangaroos is limited. Developing a better understanding of these topics is essential in creation of effective management strategies. The following thesis explores multiple aspects of behavioural ecology and health in free ranging eastern grey kangaroos. Motion detecting infra-red camera traps were used to assess activity patterns and social interactions, as well as the suitability of this tool for measuring behaviour in this species. Activity patterns were compared between a modified and natural site. The location of 23 road killed kangaroos was studied to evaluate what influences road mortality. DNA extracted from tissue and blood samples were used to conduct microsatellite analysis and investigate genetic structure of the population. Baseline haematology, blood chemistry, and acute phase protein parameters were examined for eight kangaroos including three adult males, three adult females and two sub-adult males to assess health. The aim of the research was to expand the existing knowledge of the behaviour, social organisation, population dynamics and health of eastern grey kangaroos to assist in developing more informed and effective management strategies for this species. Research was conducted at two sites in NSW, Yarramundi paddocks at the Hawkesbury campus of WSU, Richmond, NSW; an active farmland site fragmented by an urban environment consisting of 308 ha of pasture, grassland, marshes and open woodland, and the Emirates One and Only Wolgan Valley Resort, Newnes, NSW; a largely undeveloped area and conservation reserve at an eco-resort situated on 1619 ha of grasslands, woodland and riparian areas surrounded by the sandstone cliffs of World Heritage listed National Parks. Camera trap data was consistent with activity patterns of eastern grey kangaroos observed on foot in previous studies. The behaviour of kangaroos appeared to be influenced by the presence of cameras, however no kangaroos retreated from cameras and all appeared to become habituated to cameras after eight months. The findings suggest that camera traps are suitable for assessing the diurnal activity of kangaroos, however nocturnal activity appeared to be underrepresented. Observations of unusual fighting behaviour illustrates the potential for camera traps to enable capture of novel observations. Comparison of camera trap data showed that kangaroos at the modified site had a higher density, spent more time in larger groups, and had an earlier peak activity time than those at the natural site. More vigilance (standing still and scanning for threats) and less feeding were observed at the modified site. The higher population density at the modified site is likely to be a result of increased resources and restricted dispersal. The earlier peak activity time observed at the modified site may be in response to artificial lighting. Increased vigilance may be due human presence, and visual barriers in modified landscapes that reduce the line of sight. Reduced feeding time is probably a result of the higher nutritional content of pasture grasses at the modified site. Assessment of factors that influence kangaroo road mortality at the modified site demonstrated that more mortalities occurred during periods of low temperature and low rainfall, and during the waning gibbous phase of the lunar cycle. Periods of low temperature and low rainfall reduce forage quality, causing kangaroos to travel further to find high quality vegetation. High moon illumination provides increased visibility and allows for greater mobility of kangaroos. Significantly more road mortalities occurred a short distance from the end of a section of street lights. Gaps in roadside lighting are likely to reduce motorists’ ability to visually detect animals on roads while their eyes adjust to different lighting levels. Investigation of the genetic structure within the population indicated one pair of kangaroos were full siblings, and a high proportion were identified as half siblings. Six positive parentage assignments were detected. The locus used for microsatellite analysis were polymorphic and highly informative for use in the study population. No genetic spatial autocorrelation was detected. Examination of health parameters of free-ranging eastern grey kangaroos found preliminary differences in both the haematological and blood chemistry values of kangaroos of different ages and genders. The kangaroo serumhad a strong antibacterial response to Klebsiella pneumoniae, and moderate responses to Escherichia coli and Staphylococcus aureus. Haptoglobin and serum amyloid A were present in kangaroo serum, but only haptoglobin was elevated in a kangaroo with necrotic wounds. Results confirm that camera traps are suitable for assessing the diurnal activity of eastern grey kangaroos and should be incorporated in into future studies to reduce observer effect and costs, thus enabling effective long term monitoring. The expanded knowledge of the factors found to increase kangaroo road mortality enable more effective road design planning and wildlife management strategies such as targeted wildlife crossing structures and warning signs. Understanding of the genetic structure and dispersal patterns occurring within these free-ranging populations, and their health, will assist in effective population monitoring, which is necessary for the successful management of kangaroo populations in increasingly developed landscapes. Overall, the information gained from this research is essential for developing effective management practices for high density kangaroo populations in developed areas, which is necessary as a result of the increasing development and habitat fragmentation across Australia.

The transforming growth factor beta (TGFβ)/activin signaling pathway has a number of documented roles during wound healing and is becoming increasingly appreciated as a vital component of multi-tissue regeneration. The leopard gecko (Eublepharis macularius) is able to spontaneously, and repeatedly, regenerate its tail following tail loss. We thus examined the expression and localization of several key components of the TGFβ/activin signaling pathway during tail regeneration of the leopard gecko. We observed a marked increase in phosphorylated-Smad2 expression among regenerating tissues corresponding to the location of the regenerate blastema. Interestingly, we observe that during early regeneration there appears to be an absence of TGFβ family member TGFβ1 and instead a strong upregulation of activin-βA. We also observe the expression of EMT transcription factors Snail1 and Snail2 in blastemal tissue. These observations combined with other data provide strong support for the importance of unique and non-overlapping expression patterns of different TGFβ ligands during multi-tissue regeneration

abstract: Traumatic injury to the central nervous or musculoskeletal system in traditional amniote models, such as mouse and chicken, is permanent with long-term physiological and functional effects. However, among amniotes, the ability to regrow complex, multi-tissue structures is unique to non-avian reptiles. Structural regeneration is extensively studied in lizards, with most species able to regrow a functional tail. The lizard regenerated tail includes the spinal cord, cartilage, de novo muscle, vasculature, and skin, and unlike mammals, these tissues can be replaced in lizards as adults. These studies focus on the events that occur before and after the tail regrowth phase, identifying conserved mechanisms that enable functional tail regeneration in the green anole lizard, Anolis carolinensis. An examination of coordinated interactions between peripheral nerves, Schwann cells, and skeletal muscle reveal that reformation of the lizard neuromuscular system is dependent upon developmental programs as well as those unique to the adult during late stages of regeneration. On the other hand, transcriptomic analysis of the early injury response identified many immunoregulatory genes that may be essential for inhibiting fibrosis and initiating regenerative programs. Lastly, an anatomical and histological study of regrown alligator tails reveal that regenerative capacity varies between different reptile groups, providing comparative opportunities within amniotes and across vertebrates. In order to identify mechanisms that limit regeneration, these cross-species analyses will be critical. Taken together, these studies serve as a foundation for future experimental work that will reveal the interplay between reparative and regenerative mechanisms in adult amniotes with translational implications for medical therapies.
Dissertation/Thesis
Differentially Expressed Genes in the Early Regenerating Lizard Tail
Gene Ontology of Differentially Expressed Genes in the Early Regenerating Lizard Tail
KEGG and Reactome Pathway Analysis of Differentially Expressed Genes in the Early Regenerating Lizard Tail
3D Reconstruction of an Alligator Regenerated Endoskeleton
Lateral 2D Serial Sections of a Regenerated Alligator Tail
Doctoral Dissertation Biology 2020