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Yung, Chong Wing. "Tissue and metabolic engineering of biohybrid artificial organs." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3226.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005Thesis research directed by: Chemical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Hamadicharef, Brahim. "Artificial intelligence-based approach to modelling of pipe organs." Thesis, University of Plymouth, 2005. http://hdl.handle.net/10026.1/1694.
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The aim of the project was to develop a new Artificial Intelligence-based method to aid modeling of musical instruments and sound design. Despite significant advances in music technology, sound design and synthesis of complex musical instruments is still time consuming, error prone and requires expert understanding of the instrument attributes and significant expertise to produce high quality synthesised sounds to meet the needs of musicians and musical instrument builders. Artificial Intelligence (Al) offers an effective means of capturing this expertise and for handling the imprecision and uncertainty inherent in audio knowledge and data. This thesis presents new techniques to capture and exploit audio expertise, following extended knowledge elicitation with two renowned music technologist/audio experts, developed and embodied into an intelligent audio system. The Al combined with perceptual auditory modeling ba.sed techniques (ITU-R BS 1387) make a generic modeling framework providing a robust methodology for sound synthesis parameters optimisation with objective prediction of sound synthesis quality. The evaluation, carried out using typical pipe organ sounds, has shown that the intelligent audio system can automatically design sounds judged by the experts to be of very good quality, while significantly reducing the expert's work-load by up to a factor of three and need for extensive subjective tests. This research work, the first initiative to capture explicitly knowledge from audio experts for sound design, represents an important contribution for future design of electronic musical instruments based on perceptual sound quality will help to develop a new sound quality index for benchmarking sound synthesis techniques and serve as a research framework for modeling of a wide range of musical instruments.
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Xiang, Lina. "The development of artificial artery and artificial uterus from the peritoneal-derived tissue capsule /." [St. Lucia, Qld], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18118.pdf.
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Benson, Jimetria Patrice. "Towards the development of a bioartificial pancreas : alginate bead stability and prolonged function of immunoisolated insulinomas." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/11297.
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Robertson, Lesley M. "Blood compatibility of modified biomaterials : application of selected in vitro and ex vivo procedures." Thesis, University of Strathclyde, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481548.
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Smith, Antony Christopher Jonathan. "The development of novel membranes for use in biohybrid artificial organs." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424344.
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Blessing, Victoria Myriam Patricia. "User innovation of medical technologies in a developing country setting : the case of lower limb prostheses in Malawi." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/54506/.
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As is well known, users can make significant contributions to innovations, including innovating themselves. However, much work on user innovation has focussed on developed countries. The question remains whether and how users innovate in a developing country setting. Bodies of literature that explicitly consider innovations in such settings emphasise the influence of limitations. This thesis therefore investigates how limitations shape the creation and sharing of innovations by users. This issue is analysed for medical technologies, because these can have different user groups, including patients, who have been little focussed on, even in developed countries. In this setting, a focus on innovation as defined relatively inclusively is most suitable, and therefore the term 'changes' is often used rather than 'innovations' to express this inclusiveness. By comparing the changes made to the same kind of technology by different groups of users in different settings with different limitations, the influence of these limitations can be analysed. Therefore, data were collected on changes made by patients as well as orthopaedic technicians to lower limb prostheses in two orthopaedic centres in Malawi. First, observations were conducted of the production process for prostheses, followed by semi-structured interviews with orthopaedic technicians and patients, and with additional experts to understand the broader context. It was found that patients and orthopaedic technicians did make many changes. Three kinds of limitations were identified, that influence these changes by users. Like users in developed countries, patients and orthopaedic technicians make these changes to fulfil their needs because available products and services are not satisfactory. Limitations both restrict what products and services are available to users, and also influence the characteristics of the creation and sharing of changes by users. Many users reported on efforts to share their changes with others despite the limitations, often due to a sense of professional collegiality and solidarity. In summary, limitations help to explain how changes by users occur in developing countries, but also how any accumulation of such changes users make is restricted. Improving this situation could help less developed countries in making better use of any user innovations that do occur, and thus contribute to their development more generally.
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Novello, Waldyr Parolari. "Dispositivo para oxigenação e remoção de dioxido de carbono do sangue, em circuitos de circulação extracorporea." [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/262920.
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Orientadores: Antonio Celso Fonseca de Arruda e Adolfo Alberto LeirnerTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: O presente trabalho refere-se ao projeto, construção e avaliação de um dispositivo capaz de oxigenar e remover o dióxido de carbono do sangue durante circulação extracorpórea em operações cardíacas ou em procedimentos de suporte pulmonar. O funcionamento do dispositivo baseia-se na exposição de finas camadas de sangue a uma região com alta concentração de oxigênio. Nele, o sangue que passa por um reservatório cilíndrico, disposto horizontalmente, é exposto ao oxigênio através da rotação de discos imersos no sangue e fixos a um eixo central. A avaliação foi realizada através de testes "in vitro" e "in vivo" onde foram analisados parâmetros como: transferência gasosa, hemólise, gradiente de pressão, redução do número de plaquetas, volume interno e eficiência dos sistemas de controle de gases desenvolvidos. Através do estudo dos parâmetros construtivos e operacionais foi possível obter um dispositivo em condições seguras de utilização com fluxos de sangue de até 1,5 L/min. O oxigenador desenvolvido agrega as principais vantagens dos oxigenadores de bolhas e de membrana, sendo estes os dois tipos de oxigenadores atualmente mais utilizados nos centros cirúrgicos do mundo. Estas vantagens estão relacionadas com a eficiência, recursos operacionais, segurança quanto a vazamentos, custo e lesão aos constituintes sangüíneos
Abstract: This paper presents the design, construction and evaluation of a device capable of oxygenating and removing the carbon dioxide fTom the blood during cardiac surgical procedures requiring cardiopulmonary bypass or in pulmonary support procedures. The device works based on the exposure of thin layers of blood to a higWyoxygen concentrated region. Blood flows through a horizontally set cylindricalreservoir exposed to oxygen by the rotation ofblood immersed discs fixed to a central axis. Evaluation was performed by "in vitro" and "in vivo" tests where gas transfer, hemolysis, pressure drop, platelets number, priming volume and efficiency of developed gas control system were analyzed. The study of the design and operational parameters yielded a device with safe conditions ofuse with blood flows up to 1.5 L/min. The developed device has the main advantages of the two types of blood oxygenators presently used in the world regarding to efficiency, operational resources, leakage safety and trauma to blood elements
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
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Tziampazis, Evangelos. "Engineering functional, insulin-secreting cell systems : effect of entrapment on cellular environment and secretory response." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/10026.
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Cam, Doruk. "Understanding the role and improving the properties of a protective barrier membrane for a bioartificial pancreas." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/11309.
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Silva, Bruno Utiyama da. "Avaliação e aperfeiçoamento de uma bomba de sangue centrífuga implantável ápice ventricular para assistência cardíaca." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264976.
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Orientadores: Carlos Kenichi Suzuki, Aron José Pazin de AndradeDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Neste trabalho, foi realizado um estudo experimental de uma Bomba de Sangue Ápice Ventricular (BSAV) para sua análise como um dispositivo de assistência ventricular. Este estudo faz parte do desenvolvimento desta bomba e serviu como fundamentação na evolução do projeto. A BSAV é uma bomba de sangue centrífuga de fluxo contínuo, para ser utilizada como dispositivo de assistência ventricular em pacientes com doenças cardíacas crônicas. Foi realizado um estudo de posicionamento anatômico, onde a bomba foi implantada em um coração de um porco e não foram encontrados indícios de possíveis danos aos tecidos e órgãos circunvizinhos. Em seguida, foi feito um ensaio experimental, onde foi comparado o desempenho de protótipos com características distintas, visando sua otimização em relação ao desempenho hidrodinâmico. Também foi realizado um estudo para avaliação do trauma as células do sangue causado pela ação da bomba, no qual os resultados mostraram um baixo dano as células. A seguir, foi feito estudo com um protótipo conectado em um simulador cardiovascular híbrido (matemático e físico), onde este protótipo às condições simuladas de um sistema cardiovascular com insuficiência cardíaca. Com a BSAV conectada ao sistema obteve-se, uma melhora no fluxo de sangue, frequência cardíaca e pressão aórtica. Os resultados indicam que a BSAV é adequada para aplicação como dispositivo de assistência ventricular esquerda e é uma alternativa promissora no tratamento de pacientes com doenças cardíacas crônicas
Abstract: In this work an experimental study was realized with the Apico-Ventricular Blood Pump (AVBP) used as a ventricular assist device. This study is part of the device's development and the results were used for project evaluation and improvement. AVBP is a continuous flow centrifugal blood pump for ventricular assistance in chronic cardiac patients. Initially, an anatomic study was performed, in this study an AVBP prototype was implanted in a corpse of a pig, the clinical staff appointed, none damage to the nearby tissues and organs due to the contact with the device. Following step consists in an experimental hydrodynamic performance test. For this test the prototypes used had distinct specific construction characteristics variations among themselves, for device optimization, the performance of these different prototypes were compared, and the prototypes which presented a better performance had their characteristic adopted in the project. A study to determine the traumatic effect of the pump on blood cells was conducted, the results showed low damage to the blood cells. A hybrid mock loop circulation system (mathematical and physic) where the pump, was connected to a system with heart disease, was used. When the AVBP was inserted in the system, cardiac output, heart rate and aortic pressure went to normal values. All results indicated the performance of the AVBP as ventricular assist device, an alternative for treatment of patients with cardiac chronic diseases
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Mudigonda, Ashwin. "Static and Dynamic Characterization of Ionic Polymer Metal Composites - 'Artificial Muscles'." Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1142538201.
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Bock, Eduardo Guy Perpétuo. "Projeto, construção e testes de um dispositivo de assistência ventricular = bomba de sangue centrífuga implantável." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263298.
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Orientadores: Antonio Celso Fonseca de Arruda, Aron José Pazin de AndradeTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Uma Bomba de Sangue Centrífuga Implantável (BSCI) foi projetada e construída para assistência ventricular de longa duração no tratamento de pacientes portadores de doenças cardiovasculares. A proposta do projeto foi desenvolver um Dispositivo de Assistência Ventricular (DAV) com custos reduzidos, originalidade de desenho e tecnologia nacional. A geometria do rotor da bomba, aliando um cone em espiral com aletas centrífugas, deu origem ao pedido de Patente de Invenção (PI 0706163-3). O desenvolvimento de seus sistemas propulsores se inclui no Projeto Temático FAPESP nº 2006/58773-1. A metodologia baseou-se em testes individuais dos mancais, atuador e rotor, seguidos de testes do conjunto da BSCI em bancada, com sangue humano e em animais. Foram realizadas simulações numéricas por computador que resultaram no dimensionamento da bomba e definição da sua geometria. Foi testado o atrito nos mancais e os resultados que apresentaram maior durabilidade foram do par alumina-polietileno. Testes em dinamômetro resultaram na caracterização do propulsor eletromagnético, um motor sem escovas trifásico de corrente contínua, e seu controlador eletrônico baseado na técnica de controle sem sensores. Foram realizados testes de hemólise de acordo com as Normas ASTM F1830 e ASTM F1841 para quantificar os danos causados ao sangue pela BSCI e seu índice de hemólise foi de 0,0054 mg/100L, considerado excelente. Testes prospectivos em animais para avaliação do implante resultaram na possibilidade de posicionamento da bomba no tórax ou abdome. Após os testes realizados, a BSCI projetada e construída foi considerada uma opção segura para o tratamento das doenças cardiovasculares. Como trabalhos futuros, serão realizados mais testes em animais para avaliação do funcionamento da BSCI antes dos testes em pacientes
Abstract: An Implantable Centrifugal Blood Pump was developed for long-term ventricular assistance in cardiac patients. In vitro tests were performed, as wear evaluation, performance tests and hemolysis tests in human blood. Preliminary tests were performed with a non-implantable pump in order to properly locate the inlet port. Numerical computational simulations were performed in order to predict its best geometry. Wear evaluations helped to select the best materials for double pivot bearing system proposed to achieve longer durability. Performance tests pointed the best impeller geometry. The Implantable Centrifugal Blood Pump was compared with other two blood pumps. One is a centrifugal blood pump for cardiopulmonary bypass and the other is a similar implantable device called Gyro - Nedo Pump. The proposed implantable centrifugal blood pump showed the best performance. But, its results showed a strong descendant curve in high flow. Other prototype was manufactured with a different inlet port angle to overcome this problem. According to ASTM, the normalized index of hemolysis (NIH) tests were performed "In Vitro" with human blood in closed circuit (mock loop) in normalized conditions, as flow of 5 L/min and total pressure ahead of 100 mm Hg. After six hours, NIH measured 0.0054 mg/100L that can be considered excellent since it is close to the minimum found in literature (between 0.004 g/ 100L e 0.02 g/ 100L). Prior to evaluate performance during "In Vivo" animal studies, anatomical studies were necessary to achieve best configuration and cannulation for Left Ventricular Assistance. Results were considered satisfactory and "In Vivo" tests will be performed looking forward to implant it in patients
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
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LEBRAO, GUILHERME W. "Viabilidade de fabricação de tubo para prótese de membro inferior em compósito híbrido epoxi carbono-vidro." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11498.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Bezdidko, M. "Bioprinter." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/45891.
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Leme, Juliana. "Projeto, desenvolvimento e ensaios "In Vitro" de novo modelo de bomba de sangue para circulação extracorpórea = bomba espiral." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263547.
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Orientadores: Cecília Amélia de Carvalho Zavaglia, Aron José Pazin de AndradeDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Um modelo de bomba de sangue para circulação extracorpórea (CEC) está sendo desenvolvida, esta denominada Bomba Espiral (BE). Essa bomba é composta por um fuso cônico com rosca de duas entradas, montado por dois rolamentos em um eixo de aço inoxidável, fixado a um cone externo. O movimento de rotação do fuso cônico é gerado por acoplamento magnético a um motor, através de dois imãs de seis polos. Esse trabalho tem como objetivo desenvolver protótipos com modificações estruturais, baseados em estudos prévios, realizados no Baylor College of Medicine em 1997, e realizar ensaios de desempenho hidrodinâmico, para determinar a melhor geometria, e ensaios para determinar o Índice Normalizado de Hemólise (INH). Foram realizados ensaios In Vitro, em um circuito de teste fechado e os dados de pressão, fluxo e rotação foram registrados. Com os dados obtidos, foram geradas curvas de desempenho hidrodinâmico (pressão x fluxo) em diferentes rotações, para cada protótipo os quais foram comparados entre si. O modelo da BE que apresentou o melhor desempenho possui características como imã maior, cone externo mais cônico e um rotor com uma profundidade de rosca maior, e este foi comparado com uma bomba utilizada como referência, Bio-Pump®. Foi verificado que a BE possui um melhor desempenho hidrodinâmico. Foi realizado o ensaio In Vitro para determinação do INH, calculado a partir da Hemoglobina Livre no Plasma, seguindo as diretrizes das normas ASTM F1841 e F1830. Os resultados obtidos de INH foram considerados excelentes para esta aplicação, INH = 0,0118927 ±0,0061 g/100L para a BE e INH = 0,007373± 0,004942341 g/100L para a Bio- Pump®. Estes resultados não apresentam diferenças estatisticamente significantes quando comparados. Portanto, o desenvolvimento da BE resultou em um modelo viável e competitivo, apresentando excelente desempenho hidrodinâmico e um ótimo INH. O próximo passo será a confecção dos moldes injeção em policarbonato, para a realização de novos ensaios de desempenho hidrodinâmico, determinação do INH, estudo de visualização de fluxo, ensaios In Vivo e, posteriormente, Avaliação Clínica
Abstract: A model of blood pump has been developed, the Spiral Pump. This pump has an internal rotor, a conically shaped fuse, containing threads with double entrance on its surface. This rotor is supported by two bearings assembled at a stainless steel shaft, fixed to the housing's base. The rotation of the conical fuse is generated by magnetic coupling to a motor, using two annular magnets with six poles. The main objective of this paper is to describe the development methodology of this new blood pump to be for Cardiopulmonary Bypass, during cardiac surgery. Based on previous studies, six different prototypes were developed and constructed. Hydrodynamic performance tests and hemolysis test were conducted. The hydrodynamic performance tests were made in vitro, using a closed loop circuit where total pressures head, flows and rotational speed were registered. Hydrodynamic performance curves were generated (pressure x flow) in different rotational speeds, for each prototypes. The prototype #6 showed best results and the preliminary hemolysis tests were conducted to determine the Normalized Index of Hemolysis (NIH), calculate through Plasma Free Hemoglobin (ASTM F1841 and F1830). NIH results were satisfactory for this application, NIH = 0,0118927 ±0,0061 g/100L, not showing significant different when compared to results from a reference pump (Bio-Pump®, Meditronic). The next step is to produce pumps made by polycarbonate injection to be able perform new hemolysis tests, in vivo tests and, subsequently, clinical evaluation
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Afanador, López Tatiana. "La metáfora cyborg: órganos artificiales y encrucijadas." Doctoral thesis, Universitat de Barcelona, 2022. http://hdl.handle.net/10803/673890.
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En esta investigación pretendo mostrar que los híbridos cyborg son un tipo de metáforas que son fruto de la experiencia de corporalización. Estas metáforas aparecen cuando el cyborg logra que sus órganos artificiales adquieran cierta clase de plasticidad biológica, cada vez que uno de sus órganos biológicos se extiende en una máquina e, incluso, cuando se le fabrican órganos a las máquinas para que sientan el mundo exterior. De acuerdo con esto, los órganos artificiales del cyborg no se diseñan como cosas, sino como metáforas/ encrucijadas, esto es, como un punto de colisión de los trayectos por donde circulan los órganos y las máquinas, las disciplinas que contribuyen a que exista esta circulación junto con los cuerpos y las mentes que experimentan estas mezclas biotecnológicas. La presente investigación está compuesta de cuatro metáforas/ encrucijadas: las metáforas de la hibridación cibernética, las metáforas del sentido del sí mismo, las metáforas computacionales y las metáforas del devenir. Por último, se incluye la creación de un prototipo de un órgano cyborg.In this study I set out to show that cyborg hybrids are a type of metaphor resulting from the experience of embodiment. These metaphors appear when a cyborg succeeds in making its artificial organs acquire a certain biological plasticity, whenever one of its biological organs is extended into a machine, or even when organs are made to enable machines to sense the outside world. Thus, a cyborg’s artificial organs are not designed as things, but as metaphors/crossroads; that is, as intersections among the channels of circulation of organs and machines, disciplines contributing to this circulation, and bodies and minds experiencing these biotechnological amalgams. The present study is articulated around four metaphors/crossroads: metaphors of cybernetic hybridisation, metaphors of the sense of self, computer metaphors, and metaphors of becoming. Lastly, the design of an original cyborg organ prototype is included.
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Vanarse, Anup. "Neuronose: An empirical study of neuromorphic approaches for the development of an artificial olfactory system." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2020. https://ro.ecu.edu.au/theses/2353.
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Electronic nose systems, popularly known as e-noses, are one of the classic examples of analytical devices that have been researched extensively, but have had limited commercial success for applications outside of a laboratory environment. Based on the idea of emulating the biological olfactory pathway, e-nose systems generally consist of a chemo-resistive array as a sensing front-end that transduces the interaction with aromatic compounds into electrical signals. In the next stage, a signal conditioning unit performs pre-processing and feature extraction, and modulates the sensor responses into unique “odour-prints” to represent a chemical compound. Finally, a pattern-recognition engine is implemented that provides odour identification results. While this three-stage architecture seems simplistic, the realisation of each stage is significantly complex, starting from the selection of appropriate sensing materials for the front-end array to the handling of the highly multi-dimensional data generated, and the implementation of effective pattern-recognition algorithms for this data.
Although advances in computing techniques have enabled a variety of algorithms for preprocessing, feature extraction, and pattern-recognition, their short-comings in terms of computational resource requirement, processing latency, and classification accuracy have largely limited the application of e-nose systems to laboratory environments. Moving away from statistical pattern-matching techniques, e-nose systems greatly benefited from application of conventional machine learning approaches for generation of meaningful features, application of dimensionality reduction, and more advanced pattern-recognition techniques. However, these improvements were insufficient to overcome the effects of their data-intensive structure and implementation complexity that hindered their performance in real-world applications.
The emergence of neuromorphic engineering, a bio-inspired method that mimics the neuro-biological architecture by encoding and processing information using sparse spike-based representation with minimal power consumption, delivered promising results for vision and auditory sensors. With increasing interest in developing low-power and robust chemical sensors, the application of neuromorphic engineering concepts for electronic noses has provided an impetus for research focusing on improving these instruments.
While conventional e-nose systems apply computationally-expensive and power-consuming data processing strategies, neuromorphic olfactory systems implement the biological olfaction principles found in humans and insects simplifying the handling of multivariate sensory data by generating sparse spike-based information and applying spiking neural networks for processing. Over the last decade, research on neuromorphic olfaction has demonstrated the capability of these systems to tackle issues related to classification accuracy, processing latency, power consumption, and size-reduction that plague current e-nose implementations. Despite the progress in this field, what is lacking is a neuromorphic olfaction system that is both robust and able to provide real-time identification of volatile compounds in a practical application.
The main objective of this research has been to develop a neuromorphic pattern-recognition engine for an e-nose system that can function in real-time and provide reliable identification information. To achieve this goal, we apply and validate different spiking neural network architectures with hardware or cloud-based deployability to inform the design of models that can be applied in a real-world setting. In the process of developing neuromorphic classifiers, we also apply different data-to-spike encoding approaches to evaluate their efficiency and effectiveness to encode multivariate data in a sparse representation.
Significant contributions from this investigation include the development of neuromorphic models that provide highly accurate classification results with minimum latency, the development of a novel data encoding tool based on a de-facto standard bus used in neuromorphic systems, demonstration of the integration of a neuromorphic pattern-recognition model with a commercial e-nose system through a real-world application, and preliminary results showing the applicability of the proposed neuromorphic models in e-tongue systems for the development of neuromorphic gustatory systems. Overall, through this work, several novel approaches for implementation of a neuromorphic framework as a pattern recognition engine for rapid and reliable classification of continuous multi-variate e-nose data are presented.
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Vieira, Junior Francisco Ubaldo. "Analise do perfil hidrodinamico em diferentes modelos de bombas de roletes utilizadas em circulação extracorporea." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/309535.
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Orientador: Reinaldo Wilson VieiraTese (doutorado)- Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Introdução: Dentre os equipamentos utilizados em circulação extracorpórea, as bombas de roletes têm grande importância, com modelos disponíveis de vários fabricantes. O ajuste dos roletes é um fator importante nas taxas de hemólise e o potencial hemolítico difere em cada um deles. Pesquisadores nem sempre abordam detalhes sobre os perfis do leito rígido supondo que as formas padronizadas de ajuste garantem valores iguais e comparáveis para todos os modelos de bombas de roletes. Dispomos principalmente de dois métodos para o ajuste de bombas de roletes e nenhum deles considera as características de impulsão do fluido, definida pelo perfil do leito rígido. Objetivo: O objetivo desse trabalho é analisar o perfil hidrodinâmico de três diferentes modelos de bombas de roletes comercializados no Brasil e sua influência no fluxo e refluxo. Materiais e Métodos: Foram utilizados tubos de silicone de 9,5x1,6; 9,5x2,4; 13x2,4 mm de diâmetro de dois fornecedores diferentes. Os testes foram realizados em solução fisiológica e solução análoga ao sangue. O perfil hidrodinâmico de três bombas de roletes foi realizado por medidas de velocidade de queda e calibração dinâmica. Foi investigada a variação das medidas de velocidade de queda com o tempo e testes de compressão em equipamento servo-hidráulico. Os refluxos foram visualizados em aspirador de sangue e reservatório de cardiotomia com medidas simultâneas. Resultados: Os perfis hidrodinâmicos apresentaram diferenças em suas variâncias para medidas de velocidade de queda (P<0,01) e calibração dinâmica (P<0,0001). A tensão residual nos tubos de silicone ocasionou redução nas medidas de velocidade de queda com o tempo (P<0,0002) e foram confirmadas pelos testes de compressão (P<0,0001). Conclusão: Os ajustes realizados pelos métodos de velocidade de queda e calibração dinâmica são dependentes da forma do leito rígido. Comparações envolvendo bombas de roletes devem ser feitas com cautela. A tensão residual em tubos de silicone compromete a repetitividade dos ajustes feitos pelo método de velocidade de queda.
Abstract: Introduction: Among the equipment used in cardiopulmonary bypass, roller pumps have great importance, with models available from several manufacturers. The roller adjustment is an important factor in the rates of hemolysis and the hemolytic potential differs in adjustment. Researchers do not always address details on the profiles of the raceway accepting that the forms of standardized settings ensure equal and comparable values for all models of roller pumps. There are two methods for setting roller pumps and none considers the dynamic characteristics of the fluid, defined by the profile of the raceway. Objective: The aim of this study is to analyze the hydrodynamic profile of three different models of roller pumps commercialized in Brazil and its influence on the flow and back flow. Materials and methods: We used silicone tubes of 9.5x1.6, 9.5 x2.4 and 13x2.4 mm in diameter from two different suppliers. The tests were performed in saline and solution analogous to blood. The hydrodynamic profile in three roller pumps was achieved by measurements of drop rate and dynamic calibration. The drop rate variations were investigated in silicone tubes by measurements of drop rate and the compression tests in servo-hydraulic equipment. Retrograde flows were viewed in blood aspirator and cardiotomy reservoir. Results: The hydrodynamic profiles showed differences in their variances for measurements of drop rate (P <0.01) and dynamic calibration (P <0.0001). The residual stress in the silicone tubes caused reduction in drop rate with time (P<0.0002) and were confirmed by compression tests (P <0.0001). Conclusion: The adjustments made by the methods of drop rate and dynamic calibration are dependent on the raceway profile. Comparisons involving roller pumps must be made with caution. The residual stress in the silicone tubes compromises repeatability of adjustments made by the drop rate method.
Doutorado
Pesquisa Experimental
Doutor em Cirurgia
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Poorkhalil, Ali Verfasser], Jochen [Akademischer Betreuer] [Büchs, and Khosrow [Akademischer Betreuer] Mottaghy. "Impact of red cell distribution in sheared blood flow upon quantification of hemolysis rate in artificial organs / Ali Poorkhalil ; Jochen Büchs, Khosrow Mottaghy." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130402924/34.
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Vázquez-Salceda, Javier. "The role of norms and electronic institutions in multi-agent systems : the HARMONIA framework /." Basel [u.a.]: Birkhäuser, 2004. http://www.loc.gov/catdir/enhancements/fy0812/2004042072-d.html.
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Knirsch, Marcos Camargo. "Síntese e caracterização de derivados de hemoglobina para aplicação terapêutica." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9135/tde-29092015-162845/.
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A transfusão de sangue é uma intervenção terapêutica capaz de salvar muitas vidas. Entretanto, transfusões também apresentam uma alta gama de possíveis eventos adversos, questões logísticas, econômicas e sociais. Dentre as principais preocupações terapêuticas estão a incompatibilidade (principalmente do sistema ABO), a transmissão de microrganismos patogênicos, os distúrbios imunomodulatórios, as reações hemolíticas, o aumento estatístico do risco de morte proporcional ao volume de sangue infundido, dentre outros. Diversas alternativas às transfusões sanguíneas são propostas na literatura científica, dentre elas o desenvolvimento de transportadores de oxigênio que utilizam a hemoglobina, comumente intitulados substitutos sanguíneos. Neste âmbito, o presente estudo teve como objetivo o desenvolvimento de uma rota de síntese e a síntese de partículas de gelatina contendo hemoglobina polimerizada. Para tanto, realizou-se a síntese do polietileno glicol bis-[succinimidil succinato], extraiu-se e polimerizou-se com glutaraldeído ou polietileno glicol bis-[succinimidil succinato] hemoglobina de sangue bovino e, partículas de gelatina coriácea ou óssea contendo hemoglobina polimerizada foram sintetizadas e caracterizadas. A síntese do polietileno glicol bis-[succinimidil succinato] (SSPEG) foi caracterizada por espectroscopia RAMAN, análise diferencial de calorimetria (DSC) e os resultados obtidos indicaram o sucesso das reações. O produto da reação de polimerização da hemoglobina e albumina com o SSPEG foi verificado por SDS-PAGE e os resultados obtidos indicaram a formação com sucesso de polímeros de alta massa molecular. As partículas contendo hemoglobina polimerizada geradas com gelatina coriácea apresentaram diâmetro hidrodinâmico de 1370 nm, dispersividade de 0,029 e potencial zeta de -36,1 mV. As partículas contendo hemoglobina polimerizada geradas com gelatina óssea apresentaram diâmetro hidrodinâmico de 438 nm, dispersividade de 0,563 e potencial zeta de -24,5 mV. Os resultados obtidos sugerem a aplicabilidade da gelatina coriácea para a produção de partículas contendo hemoglobina polimerizada com possível aplicação como transportador de oxigênio.Blood transfusion is a therapeutic intervention that can save many lives. However, transfusion is also related to several possible adverse therapeutic events and logistic, economic and social concerns. Among the major therapeutic concerns are incompatibility (mainly of the ABO group system), pathogenic microorganisms\' transmission, immunomodulatory disturbances, hemolytic reactions, death risk increase that is proportional to the infused volume, among others. Several alternatives to blood transfusion are proposed in the scientific literature. Among them is the development of hemoglobin based oxygen carriers, commonly entitle blood substitutes. To this extent, the present work aimed to develop a synthetic route and to synthesize gelatin particles containing polymerized hemoglobin. To this purpose PEG bis(succinimidyl succinate) was synthesized, bovine hemoglobin was extracted and polymerized with glutaraldehyde or PEG and polyhemoglobin contained particles of gelatin from leather or bones were synthesized and characterized. PEG bis(succinimidyl succinate) synthesis was characterized by RAMAN spectroscopy and by differential scanning calorimetry (DSC) and the obtained results indicated the successful synthesis. The reaction product of the polymerization of hemoglobin or albumin with PEG was verified by SDS-PAGE and the results indicated the successful formation of high molecular mass polymers. The particles generated with leather gelatin and polyhemoglobin had a hydrodynamic diameter of 1370 nm, dispersity of 0.029 and zeta potential of -36.1 mV. Particles generated with bone gelatin and polyhemoglobin had hydrodynamic diameter of 438 nm, dispersity of 0.563 and zeta potential of -24.5 mV. The obtained results suggest the applicability of leather gelatin for the production of polyhemoglobin containing particles aiming to the development of a hemoglobin based oxygen carrier.
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Turri, Fabio. "Análise teórico-experimental do transporte de oxigênio e gás carbônico em oxigenadores de sangue." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3132/tde-01122006-163111/.
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Este trabalho apresenta o desenvolvimento de um simulador numérico para o transporte convectivo-reativo, não linear, de oxigênio, em oxigenadores de sangue, compostos por fibras ocas. O modelo computacional possui caráter bi-dimensional e obtém para a condição de regime permanente, a condição de saída do sangue, frente a uma condição de entrada especificada. Os parâmetros de entrada do sangue são: vazão, temperatura, pH, PCO2 , PO2 e concentração de hemoglobina. Já os parâmetros de entrada do gás são, basicamente: vazão, temperatura, umidade relativa, frações molares de oxigênio e gás carbônico. O simulador numérico também contempla a simulação do transporte de gás carbônico, uma vez que a afinidade da oxihemoglobina é afetada pelo pH local do sangue, que depende principalmente do conteúdo local de CO2 no sangue. O simulador baseia-se num coeficiente global de transporte de massa obtido a partir de resultados experimentais em sangue bovino. As equações utilizadas para o transporte de oxigênio e gás carbônico estão parametrizadas em função da temperatura, o que permite simular o desempenho do oxigenador em circulações extracorpóreas tanto em normo como em hipotermia. O modelo computacional foi desenvolvido para a geometria de escoamento de sangue externo a um feixe de fibras, com o gás escoando no interior das mesmas, com uma única passada de ambos os fluidos. O modelo foi aplicado para dois tipos de geometrias: feixe de fibras alinhadas e feixe de fibras em quicôncio. Adicionalmente, avaliou-se a viabilidade da predição do transporte de massa no sangue, calibrando-se o simulador numérico a partir de ensaios em água. Como principais resultados do trabalho desenvolvido, temos: 1) A modelagem utilizada para o transporte convectivo-reativo no sangue mostrou ser adequada para a calibração do simulador numérico desenvolvido. Desta forma, obteve-se uma estimativa precisa dos coeficientes locais de transporte de massa para o oxigênio e o gás carbônico. 2) A obtenção da distribuição de pH, ao longo do oxigenador, demonstrou que valores de pH alcalino elevado são observados no trajeto do sangue, na vizinhança do local de entrada de gás. 3) O simulador numérico obtido pode ser utilizado como uma ferramenta computacional de auxílio no projeto de oxigenadores de sangue. 4) Os testes com água são pouco eficientes na calibração do simulador, uma vez que, para isto, é necessário o conhecimento das difusividades de oxigênio e gás carbônico no sangue, as quais são modificadas pela ocorrência de intensificação.A numeric simulator was developed to predict the non-linear, convective-reactive, oxygen transport in hollow fibers blood oxygenators. The bidimensional computational model calculates, at the steady state condition, the blood outlet for a specified inlet condition. The blood flow inlet parameters taken into account are: flow, temperature, pH, PCO2 PO2 and hemoglobin concentration. The gas flow inlet parameters are: flow, temperature, relative humidity, molar fractions of oxygen and carbonic gas. The numeric simulator also simulates the CO2 transport, as the oxyhemoglobin affinity is affected by the pH local value, which depends mostly on CO2 local blood content. The simulator is calibrated against experimental data which allows the determination of the global mass transport coefficient for oxygen and CO2. Oxygen and CO2 blood content equations are explicitly temperature dependent to allow the simulation of both normothermic and hypothermic cardiopulmonary bypass. The computational model was tested for in-line and staggered fibers bundles. In addition, it was evaluated the advantages of simulator calibration from water tests. The principal results are: 1) The convective-reactive transport modeling showed to be adequate to the calibration of the numeric simulator. 2) Local values for pH, PCO2 and PO2 were obtained along the blood path. This analysis shows that very alkaline pH values occur at the blood path at the gas inlet side of the fiber bundle. 3) The numeric simulator can be used as a computational tool to support blood oxygenators development. 4) The water tests are not effective in the prediction of blood mass transport once different values for the oxygen and CO2 blood diffusivities were used to correlate blood-water results according to fiber bundle type, which is in agreement with other results, that point out that, at blood, intensification phenomena modifies blood gases diffusivities.
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PESQUEIRA, ELIANA I. de O. "Avaliação da força de inserção, remoção e resistência à fratura de mini-implantes utilizados nos tratamentos ortodônticos em diferentes regiões da maxila e mandíbula." reponame:Repositório Institucional do IPEN, 2014. http://repositorio.ipen.br:8080/xmlui/handle/123456789/25191.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Lawson, Alison N. "Cryopreservation effects on the in vitro and in vivo function of a model pancreatic substitute." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39540.
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The effects of two types of cryopreservation, conventional freezing and vitrification, on the in vitro and in vivo function of a pancreatic substitute were investigated. Conventional freezing uses low concentrations of cryoprotective agents (CPAs), slow cooling and rapid warming and allows ice formation. Vitrification requires high concentrations of CPAs coupled with rapid cooling and warming to achieve a vitreous, or ice-free, state. A previously published mathematical model describing the mass transfer of CPAs through the alginate matrix of the substitute and the cell membrane was expanded to incorporate heat transfer as well as CPA cytotoxicity. Our results indicate that temperature of exposure is the most critical parameter for the proper design of CPA addition and removal protocols. The use of a mathematical model is critical to ensure CPA equilibration and minimize CPA exposure. Properly designed CPA addition and removal protocols were used for vitrification. The effects of cryopreservation on the biomaterial and the cellular function of a pancreatic substitute consisting of murine insulinomas encapsulated in calcium alginate/poly-L-lysine/alginate beads were assessed. In vitro results indicate that both vitrification and conventionally frozen perform comparably to fresh. However, in vivo studies reveal that vitrified beads perform worse than both conventionally frozen and fresh beads. With adjustments, it may be possible to improve the performance of the vitrified beads. Nevertheless, for this pancreatic substitute, conventional freezing is the better method and allows successful cryopreservation.
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Ahmad, Hajira Fatima. "Cryopreservation effects on a pancreatic substitute comprised of beta cells or recombinant myoblasts encapsulated in non-adhesive and adhesive alginate hydrogels." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/48968.
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For clinical translation of a pancreatic substitute, long-term storage is essential, and cryopreservation is a promising means to achieve this goal. The two main cryopreservation methods are conventional freezing and vitrification, or ice-free cryopreservation. However, as both methods have their potential drawbacks for cryopreservation of a pancreatic substitute, they must be systematically evaluated in order to determine the appropriate method of cryopreservation. Furthermore, previous studies have indicated benefits to encapsulation in 3-D adhesive environments for pancreatic substitutes and that adhesion affects cell response to cryopreservation. Thus, the overall goal of this thesis was to investigate cryopreservation effects on model pancreatic substitutes consisting of cells encapsulated in non-adhesive and adhesive 3-D alginate hydrogels. Murine insulinoma betaTC-tet cells encapsulated in unmodified alginate hydrogels were chosen as the model pancreatic substitute in a non-adhesive 3-D environment. Murine myoblast C2C12 cells, stably transfected to secrete insulin, encapsulated in partially oxidized, RGD-modified alginate hydrogels were chosen as the model pancreatic substitute in a 3-D adhesive environment. With respect to cryopreservation effects on intermediary metabolism of betaTC-tet cells encapsulated in unmodified alginate, results indicate that relative carbon flow through the tricarboxylic acid cycle pathways examined is unaffected by cryopreservation. Additionally, insulin secretory function is maintained in Frozen constructs. However, vitrification by a cryopreservation cocktail referred to as DPS causes impairment in insulin secretion from encapsulated betaTC-tet cells, possibly due to a defect in late-stage insulin secretion. Results from Stable C2C12 cells encapsulated in RGD vs. RGE-alginate indicate that up to one day post-warming, cell-matrix interactions do not affect cellular response to cryopreservation after vitrification or freezing. Although there are differences in metabolic activity and insulin secretion immediately post-warming for DPS-vitrified RGD-encapsulated Stable C2C12 cells relative to Fresh controls, metabolic activity and insulin secretion are maintained at all time points assayed for Frozen constructs. Overall, due to results comparable to Fresh controls and simplicity of procedure, conventional freezing is appropriate for cryopreservation of betaTC-tet cells encapsulated in unmodified alginate or Stable C2C12 cells encapsulated in partially oxidized, RGD-modified alginate.
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Yoo, Doo-Sung. "Organ-machine Hybrids (Artificial Animals)." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281418915.
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Carvalho, Allan Charles Marques de. "Criopreservação de sêmen de tambaqui Colossoma macropomum em criotubo." Pós-Graduação em Zootecnia, 2013. https://ri.ufs.br/handle/riufs/6391.
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The semen cryopreservation in cryotubes reduces the time needed for filling, freezing and thawing of the samples, while optimizing the procedures for artificial fertilization. However, no study has yet been performed with tambaqui semen in this container. The aim of this study was to evaluate the influence of cryotubes (1.6 and 4.5 mL) and thawing time (60ºC/70s and 60ºC/90 s) on the quality and fertility of tambaqui cryopreserved semen. For that, semen samples were diluted in freezing solution (1:9) composed with 75% glucose 290 mOsm , 10% methylglycol and 5% egg yolk, and frozen in liquid nitrogen vapor (in a dry shipper), and stored in liquid nitrogen (-196 °C). The semen samples was thawed at 60ºC in bath water during 70s or 90s and the semen quality was evaluated (Total motility - MT; Progressive motility - MP; Curvilinear velocity - VCL; Straight-line velocity - VSL and Average path velocity - VAP). In this study was also determined the time viability of spermatozoa thawed, maintained under refrigeration at 5°C, and assessed over 24 hours. Besides the kinetic parameters were evaluated sperm morphology and membrane integrity of spermatozoa. The fertilizing capacity of semen was evaluated from the samples thawed in the best time. All parameters of sperm kinetic showed higher values when the semen samples were thawed in 90 s compared to 70 s, independently of cryotube type. No significant differences were observed in sperm kinetic parameters after thawing between samples frozen in 1.6 ml and 4.5 mL cryotubes, except for total motility that was higher in 1.6 mL (47 ± 14% ) compared with 4.5 mL cryotubes (40 ± 11%), independently of thawing time. After activation, the spermatozoa significantly reduced the values of kinetic parameters within 37 seconds, except the MT which remained constant during this period. Relying on the sperm parameters evaluated (VCL, VSL, VAP and membrane integrity for both cryotubes and MT, MP and morphology only for 1.6 mL cryotube) the frozen semen maintained the quality during 3h after thawing. The fertilization rate obtained with fresh semen (74±6%) was higher than cryopreserved semen (1.6 mL - 45±9% and 4.5 mL - 41±12%). The two cryotubes did not differ in this parameter. A high correlation (p <0.05) was observed between fertility and sperm kinetics parameters (MT - 89%, MP - 86%; VCL - 79%; VSL - APV and 69% - 78%). It is concluded that 1.6 and 4.5 mL cryotubes can be used in the cryopreservation of tambaqui semen being recommended to be thawed at 60°C for 90s and their use in fertilization procedures within 3 hours after thawing since kept at 5°C.A criopreservação de sêmen em criotubos reduz o tempo necessário para o envase, congelamento e descongelamento das amostras, além de otimizar os procedimentos de fertilização artificial. No entanto, nenhum estudo ainda foi realizado com o sêmen de tambaqui neste recipiente. Assim, o objetivo do presente trabalho foi avaliar a influência do tipo de criotubo (1,6 e 4,5 mL) e do tempo de descongelamento (60ºC/70s e 60ºC/90s) sobre a qualidade e fertilidade do sêmen de tambaqui criopreservado. Para isso, amostras de sêmen foram diluídas em solução de congelamento (1:9 v/v) composta por 75% de glicose 290 mOsm, 10% de metilglicol e 5% de gema de ovo, sendo envasadas em criotubos de 1,6 e 4,5 mL, congeladas em vapor de nitrogênio líquido no botijão dry-shipper (-175ºC) e armazenadas em botijão criogênico a -196°C. Para avaliação do tempo de descongelamento do sêmen, os criotubos foram imersas em água a 60°C durante 70 s ou 90 s e a qualidade espermática imediatamente avaliada (Motilidade total - MT; Motilidade progressiva - MP; Velocidade curvilinear - VCL; Velocidade em linha reta - VSL e Velocidade média da trajetória - VAP). Neste estudo foi determinado também o tempo de viabilidade dos espermatozoides descongelados, mantidos sob refrigeração a 5°C e avaliados durante 24 horas. Além dos parâmetros de cinética espermática foram avaliadas a morfologia e a integridade da membrana plasmática dos espermatozoides. A capacidade de fertilização do sêmen foi avaliada a partir das amostras descongeladas no melhor tempo. Todos os parâmetros de cinética espermática apresentaram valores superiores quando as amostras de sêmen foram descongeladas por 90s em relação ao tempo de 70s, independentemente do tipo de criotubo. Não foram observadas diferenças significativas nos parâmetros de cinética espermática pós-descongelamento entre as amostras congeladas nos criotubos de 1,6 e 4,5 mL, com exceção da MT que foi superior nos criotubos de 1,6 mL (47±14%) em comparação com os criotubos de 4,5 mL (40±11%), independentemente do tempo de descongelamento. Após ativação, os espermatozoides reduziram significativamente os valores dos parâmetros de cinética dentro de 37 segundos, exceto a MT que se manteve constante neste período. Baseando-se na maior parte dos parâmetros espermáticos avaliados (VCL, VSL, VAP e Integridade da membrana plásmatica para ambos os criotubos e MT, MP e Morfologia espermática somente para o criotubo de 1,6 mL) o sêmen congelado manteve sua qualidade durante 3h após o descongelamento. A taxa de fertilização obtida com o sêmen in natura (74±6%) foi superior ao sêmen criopreservado (1,6 mL - 45±9% e 4,5 mL - 41±12%). Os dois criotubos não diferiram entre si neste parâmetro. Uma alta correlação significativa (p<0,05) foi observada entre a fertilização e a cinética espermática (MT - 89%; MP - 86%; VCL - 79%; VSL - 69% e VAP - 78%). Conclui-se que os criotubos de 1,6 e 4,5 mL podem ser utilizados na criopreservação do sêmen de tambaqui, sendo recomendado seu descongelamento a 60°C por 90s e seu uso em procedimentos de fertilização dentro de 3 horas após o descongelamento desde que mantido a 5°C.
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Banaszczyk, Mariusz G. "Artificial hydrolytic enzymes." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74289.
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The efficiencies of many rigidly held cis-aquahydroxotetraazacobalt(III) complexes in promoting the hydrolysis of phosphate esters (BDNPP, BNPP, NPP) have been compared. The phosphate diester bond in ((trpn)Co(OH)(BNPP)) $ sp{+}$ is hydrolyzed at about the same rate as BNPP bound to a real enzyme from Enterobacter aerogenes and about 10$ sp{10}$ times more rapidly than free BNPP. The dramatic increase in the activity of the Co(III) complex with change in the tetraamine ligand structure can be explained in terms of a detailed mechanism of the reaction.Co(III) complexes, ((tren)Co(OH$ sb2)$(OH)) $ sp{2+}$ and ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ have been shown to be highly efficient in promoting the hydrolysis of phosphate di- and monoesters with poor leaving groups. ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ promoted hydrolysis of phosphate monoesters leads to a novel binuclear phosphato complex which is a model for the active site of Purple Acid Phosphatases.
For the first time it has been shown that hydrolysis of carboxylic esters catalyzed by ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ is truly catalytic. The hydrolytic activity of ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ has been linked to the fact that this complex chelates carboxylic acids as shown by $ sp{13}$C NMR spectroscopy and the crystal structure of ((trpn)Co($ eta sp2$-OCC(CH$ sb3) sb3) rbrack sp{2+}$. This complex is the first example of a cobalt(III) complex in which carboxylic acid is chelated.
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Philamore, Hemma. "An energetically autonomous artificial organism." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.691260.
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A key environmental concern in the 21st century is polluted water, requiring monitoring or remediation, often in locations which are hazardous, expansive, or difficult to reach. Robots capable of long term autonomous operation with the ability to tackle these environmental challenges are in great need. Microbial fuel cells (MFCs) are an emerging technology for water decontamination and electricity generation which convert biodegradable matter found in waterways, including pollutants such as algae and petrochemicals, to usable electrical power. As such MFCs present a promising, bioinspired power source for remotely operating robots, particularly where the use of more established energy-scavenging technologies is limited. One of the greatest challenges in environmental robotics is to develop machines with the compliance and adaptability that equips natural organisms for unassisted survival in uncertain and changeable surroundings. The emergence of mechanisms that closely mimic biological organisms is prevalent in state of the art research and can advance MFC powered robots by enabling them to to forage for food and locomote biomimetically. Artificial muscles with low mass and high efficiency, including electro-active polymers, are well suited to the low voltage, relatively low power, output of MFCs. This thesis presents these complementary technologies in the design of a biomimetic, energy-autonomous artificial organism capable of long term, unassisted operation. We consider artificial muscles powered by artificial metabolism in an investigation that covers three objectives: • Design of systems comprising soft ionically and electronically active polymers that may be used for both power generation in MFCs and soft actuation. • Driving bio-inspired actuation within the energy budget defined by the output of a single MFC, thereby improving the effective fusion of MFCs and soft robotics. • Showing energy autonomy through the integration of these technologies in a swimming, artificial organism, powered by an artificial digestive system and exploiting soft robotic actuation. The presented artificial organism has demonstrated feasibly application in self-powered environmental monitoring and clean-up of polluted waterways. The study shows a crucial step in the development of bio-inspired autonomous robots capable of long term self-sustainability and presents significant scope for future development.
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Goller, Aviva Idit. "Perceptual abnormalities in amputees : phantom pain, mirror-touch synaesthesia and referred tactile sensations." Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/39679/.
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It is often reported that after amputation people experience "a constant or inconstant ... sensory ghost ... faintly felt at time, but ready to be called up to [their] perception" (Mitchell, 1866). Perceptual abnormalities have been highlighted in amputees, such as sensations in the phantom when being stroked elsewhere (Ramachandran et al., 1992) or when observing someone in pain (Giummarra and Bradshaw, 2008). This thesis explored the perceptual changes that occur following amputation whist focusing on pain, vision and touch. A sample of over 100 amputees were recruited through the National Health Service. Despite finding no difference in phantom pain based on physical amputation details or nonpainful perceptual phenomena, results from Paper 1 indicated that phantom pain may be more intense, with sensations occurring more frequently, in amputees whose pain was triggerinduced. The survey in Paper 2 identified a group of amputees who in losing a limb acquired mirror-touch synaesthesia. Higher levels of empathy found in mirror-touch amputees might mean that some people are predisposed to develop synaesthesia, but that it takes sensory loss to bring dormant cross-sensory interactions into consciousness. Although the mirror-system may reach supra-threshold levels in some amputees, the experiments in Paper 3 suggested a relatively intact mirror-system in amputees overall. Specifically, in a task of apparent biological motion, amputees showed a similar, although weaker, pattern of results to normalbodied participants. The results of Paper 4 showed that tactile spatial acuity on the face was also largely not affected by amputation, as no difference was found between the sides ipsilateral and contralateral to the stump. In Paper 5 cross-modal cuing was used to investigate whether referred tactile sensations could prime a visually presented target in space occupied by the phantom limb. We conclude that perception is only moderately affected in most amputees, but that in some the sensory loss causes normally sub-threshold processing to enhance into conscious awareness.
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Anderlund, Magnus. "Dinuclear Manganese Complexes for Artificial Photosynthesis : Synthesis and Properties." Doctoral thesis, Stockholm : Dept. of organic chemistry, Stockholm university, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-396.
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Dharmawardena, Priyangi Tikiri Kumari. "Artificial hydrolytic metalloenzymes for ester hydrolysis." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322705.
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Cheung, William M. L. (William Man Lung). "Artificial phosphodiesterases : dinuclear metal complexes with bridging hydroxides." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23875.
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The reactivities of two dinuclear metals complexes with bridging hydroxides for hydrolyzing phosphrite diesters have been examined.The second-order rate constants ($ rm k sp prime sb{hyd}/M sp{-1} s sp{-1}$) for the hydroxidecatalysed hydrolysis of bridging aryl methyl phosphates in di-$ mu$-hydroxodinuclear cobalt(III) complex ($ rm Co sb2( lbrack 9 rbrack aneN sb3) sb2(OH) sb2(OP(O)(OMe)(OAr) rbrack sp{3+}$ ( (9) aneN$ sb3$ = 1,4,7-triazacyclononane) and the corresponding free aryl methyl phosphates (25$ sp circ$C and 0.1 M ionic strength) obey the following Bronsted equations: eqalign{ rm log k sp prime sb{hyd} (free diester) = -0.70 pK sb{ rm a}-0.66 & quad rm(R = 0.996) cr rm log k sp prime sb{hyd} (bridging diester) = -1.40 pK sb{ rm a} + 14.4 & quad rm (R = 0.999) cr} hese linear free energy relationships suggest that the di-$ mu$-hydroxodinuclear cobalt(III) complex, irrespective of the leaving groups hydrolyzes the bridging phosphate diesters by the same mechanism. They also indicate that the complex provides greater rate-acceleration for hydrolyzing phosphate diesters with good leaving groups than with poor ones.
La(III) cooperates with hydroxide in hydrolyzing bis(4-nitrophenyl) phosphate (BNPP). The close agreement between the titration data and the pH-rate profile indicates that the active core of the catalyst is a dinuclear La(III) complex bridged by five hydroxide ions La$ rm sb2(OH) sb5 sp+.$ The mechanism proposed for $ rm La sb2(OH) sb5 sp+$-promoted hydrolysis of BNPP involves double Lewis acid activation and intramolecular nucleophilic catalysis of the bridging hydroxide.
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Takasaki, Bryan K. "Lanthanide ions in the development of artificial nucleases." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28535.
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The kinetics and mechanism of hydrolysis of both activated and unactivated phosphate diesters in the presence of aqueous solutions of Ce(III) salts are studied in detail. In the presence of 20 mM Ce$ rm (ClO sb4) sb3 (pH 8, 37 sp circ C)$ a DNA dinucleotide (dApdA) is converted to the nucleoside (dA) and inorganic phosphate with a half-life of approximately 100 minutes. This reaction is oxygen dependent and a mechanism involving the activation of oxygen by Ce(III) to give a Ce(IV) coordinated peroxide dianion as the active species is proposed.The addition of 20 mM hydrogen peroxide to 2mM La(III) (pH 7.0, 25$ sp circ$C) results in a 34,000 fold increase in the rate of BNPP hydrolysis over that observed in the presence of 2mM La(III) alone and an overall 5 x l0$ sp8$ fold rate increase over the uncatalyzed rate. Incorporation of $ sp{18}$O from hydrogen peroxide into the inorganic phosphate product and evidence from the reaction kinetics and potentiometric titrations indicate that the mechanism involves nucleophilic attack of a La(III) coordinated peroxide dianion upon the substrate.
La(III) hydroxide clusters formed from the combination of La(III) (20 mM) and NaOM (40 mM) rapidly converts an RNA dinucleotide (ApA) to the monophosphates (2$ sp prime$-AMP and 3$ sp prime$-AMP) (t$ sb{1/2}$ = 8 sec at pH 8.7, 20$ sp circ$C). The presence of molecular oxygen does not improve the efficiency of Ce(III) in cleaving ApA; however, it does assist in the cleavage of the monophosphates which are not cleaved by Ce(III) in the absence of O$ sb2$ or La(III).
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Johansson, Olof. "Ruthenium(II) Polypyridyl Complexes : Applications in Artificial Photosynthesis." Doctoral thesis, Stockholm : Institutionen för organisk kemi, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-93.
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Fujisato, Toshiya. "Basic Studies on Polymeric Materials to be Used for Hybrid-Type Artifical Organs." Kyoto University, 1994. http://hdl.handle.net/2433/168889.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第5709号
工博第1355号
新制||工||947(附属図書館)
UT51-94-J141
京都大学大学院工学研究科高分子化学専攻
(主査)教授 筏 義人, 教授 升田 利史郎, 教授 今西 幸男
学位規則第4条第1項該当
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Jakab, Karoly Robert. "Physical mechanisms of cell rearrangements from tissue liquidity to artificial organ structures /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4426.
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Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 25, 2009) Vita. Includes bibliographical references.
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Faísca, Pedro Miguel Portela. "Comparison of organic matter decomposition between natural and artificial ponds." Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/24405.
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Litter decomposition is a key ecosystem service within aquatic ecosystems and is a complex process that is sensitive to environmental factors. The role of microbial and macrofaunal decomposers, and how it changes across environmental gradients is not yet fully understood. Decomposition was assessed across 6 biogeographical regions to determine the role of macroinvertebrates in this ecosystem service. Decomposition was estimated using standardized cotton strips, which were deployed in the mesocosms of each region. The role of macroinvertebrates was tested with an exclusion experiment which allowed or prevented the access of macroinvertebrates to cotton strips, a similar experiment was also conducted in natural ponds. After 64 days the cotton strips were collected, and mass loss and tensile strength were measured. There were significant differences in the rate of decomposition across different regions and no differences were found between systems. Macroinvertebrates played an important role, with gatherers being major players; Resumo:
A decomposição é um serviço de ecossistema chave e um processo complexo sensível a factores ambientais. O papel de decompositores microbianos e da macrofauna, e como este papel muda num gradiente ambiental não é completamente entendido. A decomposição foi avaliada em 6 zonas biogeográficas para determinar o papel de macroinvertebrados neste serviço de ecossistema. A decomposição foi estimada utilizando tiras de algodão, colocadas em mesocosmos nas diferentes regiões. O papel dos macroinvertebrados foi testado através de uma experiência de exclusão que permitia ou impedia o acesso de macroinvertebrados às tiras, uma experiência semelhante foi realizada em charcos naturais. Ao fim de 64 dias, as tiras de algodão foram recolhidas e a perda de massa e tensão foram quantificadas. Encontraram-se diferenças significativas na decomposição entre as diferentes regiões, mas não se observaram diferenças entre sistemas. Os macroinvertebrados têm um papel importante neste serviço de ecossistema, sendo as espécies colectoras as mais importantes
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Parrill, Abby Louise 1970. "Applications of artificial intelligence in drug design." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/290612.
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Computer-aided drug design is a rapidly growing area of research. The design process can proceed from two angles: either the three-dimensional structure of the biological target is known, or it is unknown. Thus the area of computer-aided drug design can be separated into a number of problems. One problem is determining the structure of a biomolecule from experimental data, as is done in chapter 2 for colominic acid polylactone. These studies determined that there are two helical structures consistent with spectral data A second problem is designing a ligand complementary to the three-dimensional structure of the target. Chapters 3 and 4 describe studies leading to the design and evaluation of neuraminidase inhibitors. These studies indicate that several inhibitors studied are competitive inhibitors of the enzyme with better binding affinities than the natural ligand. The final,and potentially most difficult problem, is to infer features about the biological target from compounds known to bind to that target. Chapters 5 and 6 describe model studies and implementation of CLEW, a program to learn rules relating structural features to biological function. Results indicate that learning based on topological features is a useful first iteration in determining the pharmacophore, or three-dimensional arrangement of functionality required for biological activity.
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Rygálová, Monika. "Steal me your €motion." Master's thesis, Vysoké učení technické v Brně. Fakulta výtvarných umění, 2021. http://www.nusl.cz/ntk/nusl-445701.
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The text deals with ways and methods of creating my diploma thesis called Steal me your €motion. The diploma thesis deals with the relationship between machine learning and emotionality. To what extent is artificial intelligence able to undergo emotional relationships and experiences defined by the physicality and experience of the human body. The topic of the work is the creation of a (fictional) inhuman entity that longs to learn from people as many bodily acts as possible that will help it infiltrate the human community. In addition to reflecting the current level of scientific knowledge, I bring an element of fiction and fiction.
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Karlsson, Erik. "Catalysts for Oxygen Production and Utilization : Closing the Oxygen Cycle: From Biomimetic Oxidation to Artificial Photosynthesis." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-56917.
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This thesis describes the development and study of catalysts for redox reactions, which either utilize oxygen or hydrogen peroxide for the purpose of selectively oxidizing organic substrates, or produce oxygen as the necessary byproduct in the production of hydrogen by artificial photosynthesis. The first chapter gives a general introduction about the use of environmentally friendly oxidants in the field of organic synthesis, and about the field of artificial photosynthesis. The second chapter describes a computational study of the mechanism of palladium-catalyzed oxidative carbohydroxylation of allene-substituted conjugated dienes. The proposed mechanism, which was supported by DFT calculations, involves an unusual water attack on a (π-allyl)palladium complex. The third chapter describes a computational study of the oxidation of unfunctionalized hydrocarbons, ethers and alcohols with hydrogen peroxide, catalyzed by methyltrioxorhenium (MTO). The mechanism was found to proceed via rate-limiting hydride abstraction followed by hydroxide transfer in a single concerted, but highly asynchronous, step as shown by intrinsic reaction coordinate (IRC) scans. The fourth chapter describes the use of a new hybrid (hydroquinone-Schiff base)cobalt catalyst as electron transfer mediator (ETM) in the palladium-catalyzed aerobic carbocyclization of enallenes. Covalently linking the two ETMs gave a fivefold rate increase compared to the use of separate components. The fifth chapter describes an improved synthetic route to the (hydroquinone-Schiff base)cobalt catalysts. Preparation of the key intermediate 5-(2,5-hydroxyphenyl)salicylaldehyde was improved by optimization of the key Suzuki coupling and change of protecting groups from methyl ethers to easily cleaved THP groups. The catalysts could thus be prepared in good overall yield from inexpensive starting materials. Finally, the sixth chapter describes the preparation and study of two catalysts for water oxidation, both based on ligands containing imidazole groups, analogous to the histidine residues present in the oxygen evolving complex (OEC) and in many other metalloenzymes. The first, ruthenium-based, catalyst was found to catalyze highly efficient water oxidation induced by visible light. The second catalyst is, to the best of our knowledge, the first homogeneous manganese complex to catalyze light-driven water oxidation.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Accepted. Paper 6: Submitted.
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Marchiori, Bastien. "Stretchable electronics towards the fabrication of organic sensors for artificial skin." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEM025.
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Le domaine de l’électronique étirable concerne les circuits électriques et électroniques qui sont élastiquement ou inélastiquement étirables par plus de quelques pourcents tout en gardant leur intégrité mécanique et électrique. Actuellement, les dispositifs électroniques étirables ont de nouvelles applications émergentes, notamment pour les intégrer sur la peau. Ces systèmes, se présentent sous la forme d’une peau artificielle, qui peut intégrer des capteurs. Ces capteurs, peuvent être aussi intégrés sur des mains robotiques, ou des prothèses, pour recréer les mêmes propriétés que la peau : toucher, pression et température. Le but de ce travail est d’identifier les stratégies et les matériaux permettant de fabriquer des dispositifs étirables possédant une capacité d’étirement comparable à celle de la peau (~15%) avec des performances proches de l’électronique rigide. Pour cela, un procédé de micro fabrication permettant de fabriquer des capteurs organiques a été développé. Les systèmes développés sont basé sur des interconnections métalliques en forme de serpentin permettant un étirement jusqu’à 80%. Ensuite, ces différents outils ont été utilisés pour fabriquer un dispositif biomédical : le transistor électrochimique organique (OECT). Ce transistor utilise un polymère conducteur pour capter des signaux physiologiques. Enfin, un capteur température a été développé. Il peut aussi capter des signaux infrarouges, à la manière de la peau humaine. Ces dispositifs peuvent supporter des déformations jusqu’à 30% de sa longueur initiales et peuvent donc être intégrer sous forme de matrice pour une utilisation sur la peau artificielleStretchable electronics concern electrical and electronic circuits that are elastically or inelastically stretchable by more than a few percents while retaining function. In order to achieve this, devices tend to be laminar and usually thin. Compared with rigid, hard conventional electronic systems in planar formats, stretchable electronic systems can be stretched, compressed, bent, and deformed into arbitrary shapes without electrical or mechanical failure within the circuits. Currently, stretchable electronic systems have many important and emerging applications in new, soft and curved bio-inspired areas, such as tuneable electronic eye cameras or artificial skin capable of mechanically invisible integration onto human skin. These sensors would be integrated on robotic or prosthetic hands to recreate the same sensing capabilities than the skin: touch, pressure and temperature. The aim of this thesis is to identified strategies and materials to make stretchable devices with stretching capabilities similar to the one of the skin (~15%) with performance close to rigid devices. In this purpose, a microfabrication process to fabricate organic sensors has been developed. The devices are based on laser cut bulk metallic stretchable interconnections with maximum elongation of 80% in PDMS matrix. Then, these tools have been used to fabricate a biosensor: the organic electrochemical transistor (OECT). The transistor is based on a conducting polymer and is able to sense physiological signal. A temperature sensor has also been developed, able to sense infrared signal, like the human skin. These devices can stand up to 30% strain and can be integrated into a matrix for artificial skin applications
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Cauchefert, Matthieu. "Rock Physics Properties of Artificial Shales: Effect of Organic Matter Characteristics." Thesis, Curtin University, 2019. http://hdl.handle.net/20.500.11937/81045.
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The objective of this project is to evaluate the influence of an array of organic matter characteristics on the physical properties (elastic and dielectric) of artificial organic-rich shales. We found evidence of the impact of the following variables: thermal maturity, kerogen type, organic particles texture and deposition method. The achievements of this study are also technical. We designed an advanced compaction cell recording petrophysical and elastic properties during consolidation and an artificial thermal maturation equipment.
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Mirzakulova, Ekaterina Viktorovna. "Natural and Artificial Flavin-Based Catalysis." Bowling Green State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1371415783.
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Henniquau, Dimitri. "Conception d’une interface fonctionnelle permettant la communication de neurones artificiels et biologiques pour des applications dans le domaine des neurosciences." Thesis, Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUN032.
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L’ingénierie neuromorphique est un nouveau champ disciplinaire en plein essor qui fait appel à des compétences en électronique, mathématiques, informatique et en ingénierie biomorphique dans le but de produire des réseaux de neurones artificiels capables de traiter les informations à la manière du cerveau humain. Ainsi, les systèmes neuromorphiques offrent non seulement des solutions plus performantes et efficientes que les technologies actuelles de traitement de l’information mais permettent également d’envisager le développement de stratégies thérapeutiques inédites dans le cadre de dysfonctionnements cérébraux pathologiques. Le groupe Circuits Systèmes Applications des Micro-ondes (CSAM) de l’Institut d’Electronique, de Microélectronique et de Nanotechnologies (IEMN) dans lequel ces travaux de thèse ont été effectués a contribué à l’émergence de ces systèmes neuromorphiques en développant une boîte à outils complète de neurones et synapses artificiels. Pour intégrer l’ingénierie neuromorphique dans la prise en charge de dysfonctionnements neuronaux pathologiques, il convient d’interfacer les neurones artificiels et les neurones vivants afin d’assurer une communication réelle entre ces différents composants. Dans ce contexte, et en utilisant les outils innovants développés par le groupe CSAM, l’objectif de ce travail de thèse a été de concevoir et réaliser une interface fonctionnelle permettant d’établir une boucle de communication bidirectionnelle entre des neurones artificiels et des neurones vivants. Les neurones artificiels développés par le groupe CSAM sont réalisés en technologie CMOS et capables d’émettre des signaux électriques biomimétiques. Les neurones vivants sont issus de cellules PC12 différenciées. Une première étape de ce travail a consisté à modéliser et à simuler cette interface entre neurones artificiels et vivants ; une deuxième partie de la thèse a été dédiée à la fabrication et à la caractérisation d’interfaces neurobiohybrides, ainsi qu’à la croissance et à la caractérisation de neurones vivants, avant d’étudier leur capacité à communiquer avec des neurones artificiels. Ainsi, un modèle de membrane neuronale représentant un neurone vivant interfacé avec une électrode métallique planaire a été développé. L’exploitation de ce modèle a permis de montrer qu’il est possible de stimuler des neurones vivants en utilisant les signaux biomimétiques issus du modèle de neurones artificiels tout en conservant des tensions d’excitation faibles. L’utilisation de faibles tensions d’excitation permettrait d’améliorer l’efficacité énergétique des systèmes neurobiohybrides intégrant des neurones artificiels et d’amoindrir le risque d’endommager les tissus vivants. Ensuite, le neurobiohybride permettant d’interfacer les neurones vivants et les neurones artificiels a été conçu et réalisé. Une caractérisation expérimentale de cette interface a permis de valider l’approche consistant à exciter un neurone vivant au travers d’une électrode métallique planaire. Enfin, des cellules neuronales vivantes issues de cellules PC-12 ont été cultivées et différenciées dans les neurobiohybrides. Une preuve expérimentale de la capacité des signaux électriques biomimétiques produits par les neurones artificiels a ainsi pu être apportée par la technique d’imagerie calcique. En conclusion, les travaux présentés dans ce manuscrit établissent clairement la preuve de concept de l’excitation de neurones vivants par un signal biomimétique dans nos conditions expérimentales et étayent ainsi la première partie de la boucle de communication bidirectionnelle entre neurones artificiels et neurones vivantsNeuromorphic engineering is an exciting emerging new field, which combines skills in electronics, mathematics, computer sciences and biomorphic engineering with the aim of developing artificial neuronal networks capable of reproducing the brain’s data processing. Thus, neuromorphic systems not only offer more effective and energy efficient solutions than current data processing technologies, but also set the bases for developing novel original therapeutic strategies in the context of pathological brain dysfunctions. The research group Circuits Systèmes Applications des Micro-ondes (CSAM) of the Institute for Electronics, Microelectronics and Nanotechnologies (IEMN) in Lille, in which this thesis work was carried out, has contributed to the generation of such neuromorphic systems by developing a toolbox constituted of artificial neurons and synapses. In order to implement neuromorphic engineering in the therapeutic arsenal for treating neurologic disorders, we need to interface living and artificial neurons to ensure real communication between these different components. In this context and using the original tools developed by the CSAM group, the main goal of this thesis work was to design and produce a functional interface allowing a bidirectional communication loop to be established between living and artificial neurons. These artificial neurons have been developed by the CSAM group using CMOS technology and are able to emit biomimetic electrical signals. Living neurons were obtained from differentiated PC-12 cells. A first step in this work consisted in modeling and simulating this interface between artificial and living neurons; a second part of the thesis was dedicated to the fabrication and characterization of neurobiohybrid interfaces, and to the growth and characterization of living neurons before studying their capacities to communicate with artificial neurons. First, a model of neuronal membrane representing a living neuron interfaced with a metallic planar electrode has been developed. We thus showed that it is possible to excite neurons using biomimetic signals produced by artificial neurons while maintaining a low excitation voltage. Low voltage excitation would improve energy efficiency of neurobiohybrid systems integrating artificial neurons and reduce the impact of harmful electrical signals on living neurons. Then, the neurobiohybrid interfacing living and artificial neurons has been designed and produced. The results obtained by experimental characterization of this interface validate the approach consisting in exciting living neurons through a metallic planar electrode. Finally, living neurons from PC-12 cells were grown and differentiated directly onto neurobiohybrids. Then, an experimental proof of the ability of biomimetic electrical signals to excite living neurons was obtained using calcium imaging. To conclude, the work presented in this manuscript clearly establishes a proof of concept for the excitation of living neurons using a biomimetic signal in our experimental conditions and thus substantiates the first part of the bidirectional communication loop between artificial neurons and living neurons
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Libotean, Dan Mihai. "Modeling the reserve osmosis processes performance using artificial neural networks." Doctoral thesis, Universitat Rovira i Virgili, 2007. http://hdl.handle.net/10803/8555.
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Una de las aplicaciones más importante de los procesos de filtración por membrana es en el área de tratamiento de agua por ultrafiltración, nanofiltración u ósmosis inversa. Entre los problemas más serios encontrados en estos procesos destaca la aparición de los fenómenos de ensuciamiento y envejecimiento de las membranas que limitan la eficacia de la operación tanto en la separación de los solutos, como en el flujo de permeado, afectando también el ciclo de vida de las membranas.Para reducir el coste de la producción y mejorar la robustez y eficacia de estos procesos es imprescindible disponer de modelos capaces de representar y predecir la eficiencia y el comportamiento de las membranas durante la operación. Una alternativa viable a los modelos teóricos, que presentan varias particularidades que dificultan su postulado, la constituyen los modelos basados en el análisis de los datos experimentales, entre cuales destaca el uso de las redes neuronales. Dos metodologías han sido evaluadas e investigadas, una constando en la caracterización de las interacciones entre las membranas y los compuestos orgánicos presentes en el agua de alimentación, y la segunda basada en el modelado de la dinámica de operación de las plantas de desalinización por ósmosis inversa.
Relaciones cuantitativas estructura‐propiedad se han derivado usando redes neuronales de tipo back‐propagation, para establecer correlaciones entre los descriptores moleculares de 50 compuestos orgánicos de preocupación para la salud pública y su comportamiento frente a 5 membranas comerciales de ósmosis inversa, en términos de permeación, absorción y rechazo. Para reducir la dimensión del espacio de entrada, y para evitar el uso de la información redundante en el entrenamiento de los modelos, se han usado tres métodos para seleccionar el menor número de los descriptores moleculares relevantes entre un total de 45 que caracterizan cada molécula. Los modelos obtenidos se han validado utilizando un método basado en el balance de materia, aplicado no solo a los 50 compuestos utilizados para el desarrollo de los modelos, sino que también a un conjunto de 143 compuestos orgánicos nuevos. La calidad de los modelos obtenidos es prometedora para la extensión de la presente metodología para disponer de una herramienta comprensiva para entender, determinar y evaluar el comportamiento de los solutos orgánicos en el proceso de ósmosis inversa. Esto serviría también para el diseño de nuevas y más eficaces membranas que se usan en este tipo de procesos.
En la segunda parte, se ha desarrollado una metodología para modelar la dinámica de los procesos de ósmosis inversa, usando redes neuronales de tipo backpropagation y Fuzzy ARTMAP y datos experimentales que proceden de una planta de desalinización de agua salobre Los modelos desarrollados son capaces de evaluar los efectos de los parámetros de proceso, la calidad del agua de alimentación y la aparición de los fenómenos de ensuciamiento sobre la dinámica de operación de las plantas de desalinización por osmosis inversa. Se ha demostrado que estos modelos se pueden usar para predecir el funcionamiento del proceso a corto tiempo, permitiendo de esta manera la identificación de posibles problemas de operación debidas a los fenómenos de ensuciamiento y envejecimiento de las membranas. Los resultados obtenidos son prometedores para el desarrollo de estrategias de optimización, monitorización y control de plantas de desalinización de agua salobre. Asimismo, pueden constituir la base del diseño de sistemas de supervisón capaces de predecir y advertir etapas de operación incorrecta del proceso por fallos en el mismo, y actuar en consecuencia para evitar estos inconvenientes.
One of the more serious problems encountered in reverse osmosis (RO) water treatment processes is the occurrence of membrane fouling, which limits both operation efficiency (separation performances, water permeate flux, salt rejection) and membrane life‐time. The development of general deterministic models for studying and predicting the development of fouling in full‐scale reverse osmosis plants is burden due to the complexity and temporal variability of feed composition, diurnal variations, inability to realistically quantify the real‐time variability of feed fouling propensity, lack of understanding of both membrane‐foulants interactions and of the interplay of various fouling mechanisms. A viable alternative to the theoretical approaches is constituted by models developed based on direct analysis of experimental data for predicting process operation performance. In this regard, the use of artificial neural networks (ANN) seems to be a reliable option. Two approaches were considered; one based on characterizing the organic compounds passage through RO membranes, and a second one based on modeling the dynamics of permeate flow and separation performances for a full‐scale RO desalination plant.
Organic solute sorption, permeation and rejection by RO membranes from aqueous solutions were studied via artificial neural network based quantitative structure‐property relationships (QSPR) for a set of 50 organic compounds for polyamide and cellulose acetate membranes. The separation performance for the organic molecules was modeled based on available experimental data achieved by radioactivity measurements to determine the solute quantity in feed, permeate and sorbed by the membrane. Solute rejection was determined from a mass balance on the permeated solution volume. ANN based QSPR models were developed for the measured organic sorbed (M) and permeated (P) fractions with the most appropriate set of molecular descriptors and membrane properties selected using three different feature selection methods. Principal component analysis and self‐organizing maps pre‐screening of all 50 organic compounds defined by 45 considered chemical descriptors were used to identify the models applicability domain and chemical similarities between the organic molecules. The ANN‐based QSPRs were validated by means of a mass balance test applied not only to the 50 organic compounds used to develop the models, but also to a set of 143 new compounds. The quality of the QSPR/NN models developed suggests that there is merit in extending the present compound database and extending the present approach to develop a comprehensive tool for assessing organic solute behavior in RO water treatment processes. This would allow also the design and manufacture of new and more performing membranes used in such processes.
The dynamics of permeate flow rate and salt passage for a RO brackish water desalination pilot plant were captured by ANN based models. The effects of operating parameters, feed water quality and fouling occurrence over the time evolution of the process performance were successfully modeled by a back‐propagation neural network. In an alternative approach, the prediction of process performance parameters based on previous values was achieved using a Fuzzy ARTMAP analysis. The neural network models built are able to capture changes in RO process performance and can successfully be used for interpolation, as well as for extrapolation prediction, fact that can allow reasonable short time forecasting of the process time evolution. It was shown that using real‐time measurements for various process and feed water quality variables, it is possible to build neural network models that allow better understanding of the onset of fouling. This is very encouraging for further development of optimization and control strategies. The present methodology can be the basis of development of soft sensors able to anticipate process upsets.
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Kim, Jung-Hee. "Developing artificial proteases and nucleases : catalytic hydrolysis of unactivated amides, nitriles and phosphates." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39317.
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Cis-diaqua cobalt complex ((L)Co(III)(OH$ sb2) sb2 rbrack sp{3+}$ promoted hydrolyses of phosphate esters, nitriles and carboxy amides are examined (L represents 1,4,7,10-tetraazacyclododecane (cyclen) and its N-methylated derivatives). ((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ is more active than any other catalysts reported to date for hydrolyzing dimethyl phosphate, acetonitrile and formyl morpholine.((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ efficiently hydrolyzes dimethyl phosphate under mild conditions (k = 3.7 $ times$ 10$ sp{-5}$ M$ sp{-1}$ sec$ sp{-1}$ at pD 6.3, 60$ sp circ$C). This represents the first hydrolysis of dimethyl phosphate (P-O bond cleavage) at neutral pH. Mechanism for the cobalt complex promoted hydrolysis of dimethyl phosphate and its implication on the role of metal ions in ribozymes is discussed.
((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ catalyzes the hydration of nitriles to amides. Acetonitrile coordinated to the cobalt complex is hydrated 10$ sp9$ times more rapidly than the uncoordinated acetonitrile at pH 7 and 40$ sp circ$C. Catalytic turnover for the hydration reaction is demonstrated for the first time with the Co(III) complex. Chelated benzamide, a key intermediate in the catalytic hydration of benzonitrile, is isolated and its crystal structure determined. Detailed kinetics and mechanistic analyses of the cobalt complex catalyzed hydration of acetonitrile including the equilibrium constant for complexation of acetonitrile to the cobalt complex (K = 0.6 M$ sp{-1})$ are reported. Synthetic utility of the catalyst including acrylamide production is discussed.
((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ efficiently hydrolyzes formyl morpholine under mild conditions (k = 7.97 $ times$ 10$ sp{-5}$ M$ sp{-1}$ sec$ sp{-1}$ at pD 6, 60$ sp circ$C). The equilibrium constant for complexation of formyl morpholine to the cobalt complex is 0.4 M$ sp{-1}.$ The equilibrium constant for complexation of amides to metal complexes had not been previously measured. The efficiency and mechanism of the cobalt complex for hydrolyzing amides are compared to those of carboxypeptidase A.
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Van, Der Meer Valentina. "Characterization of faradaic and capacitive processes in organic photoelectrodes for artificial retina prosthesis." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18406/.
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An increasing number of studies about artificial retinal prothesis have been carried out recently demonstrating the possibility to restore sight in partially sighted or blind patients. In all of such devices the fundamental component is an opotobioelectronic layer. When illuminated, this layer produces ionic current pulses of enough intensity to activate the visual cortex’s neurons. The principal objective to achieve is the deep understanding of the processes that occur at the semiconductor-liquid interface, with the purpose to develop materials that present flexibility and biocompatibility and are not subject to deterioration when in contact with an acqueous electrolyte. In this thesis I have analysed organic semiconducting pigments developed by the Linkoping University as active optobioelectronic layer. The purpose of the thesis is to investigate and characterize the faradaic and capacitive processes that occur at the interface when a light stimulated current pulse is generated. The results show that faradaic processes are favoured by a negative potential applied to the optobioelectronic layer, while with a positive potential the photocurrent is almost completely capacitive. The wavelength of the stimulating light pulse has instead no significant effect on the ratio between capacitive to faradaic current generation processes.
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Boccalon, Mariangela. "Design and synthesis of artificial porphyrin nanopores." Doctoral thesis, Università degli studi di Trieste, 2012. http://hdl.handle.net/10077/7735.
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2010/2011The regulation of transmembrane ion transport is a fundamental aspect of bioinspired chemistry which may find relevant applications in different fields ranging from pharmaceutics to sensing. In this contest the ability to form stable and well organized structures able to produce large and well defined pore in the membrane appears really promising. Several examples of such systems are present in the literature, usually formed in self-assembling processes mediated by hydrogen bonding, charge repulsion, and ion pairing. Coordination chemistry, however, has appeared only occasionally in design strategies for synthetic ion channels and pores. Recently Kobuke reported synthetic nanopores based on covalent adduct of porphyrins having six carboxylic acid groups directed up and down; the formation of hydrogen bonds between two monomers promotes their stacking and the formation of a nanopore able to span the lipid bilayer. The covalent approach for this type of macromolecules is synthetically laborious and the developments are therefore limited. In this context, the self-assembly approach, in which the macromolecules are generated by self-assembly of small and more synthetically accessible building blocks, is an attractive way to achieve the aim. In this field trans-porphyrin provides a linear substitution pattern that can be used for the construction of porphyrin-based architectures with a well-defined structure by metal mediated self-assembly. We have started a research project aimed to design synthetic metal-organic nanopores derived from the self-assembling of porphyrin ligands with proper metal fragments. In our first approach we have used trans-dipyridylporphyrins (linear difunctional ligands) which, upon binding with metal fragments such as Re(I) or Pd(II) (cis-coordinant metal fragments) may form supramolecular boxes (4+4 type). Subsequently, the porphyrins have been functionalized with groups able to give hydrogen bonds after appropriate modification, such as esters. A second part of the work was focused on the study of the ionophoric activity of the prepared compounds. Activity studies have been conducted on porphyrins and molecular squares using liposomes as models of biological membranes. Porphyrins and molecular squares without groups able to give hydrogen bonding do not show ionophoric activity. This behavior was expected because the dimension of these systems does not allow to span completely the lipid bilayer and there are not weak interactions that promote the self-assembly of the monomers. On the contrary, excellent ionophoric activity was observed with the molecular square bearing carboxylic acid. Thus, presence of hydrogen bonding groups that enable the formation of tubular, probably dimeric, structure are essential for forming the transmembrane nanopore. Ionophoric activity can be inhibited by using polyamino-dendrimers and this ability is function of their dimension. Parallel to the development of supramolecular porphyrins based nanopores, in the course of my PhD period, I studied also the ionophoric activity of cyclic phosphate-linked oligosaccharide analogues (CyPLOS) and guanosine-based amphiphiles in collaboration with prof.ssa Daniela Montesarchio, Department of Organic Chemistry and Biochemistry, University “Federico II” of Napoli.
XXIV Ciclo
1984