963 resultados para Process Monitoring
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Dissertation to obtain the Master degree in Electrical Engineering and Computer Science
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We aimed to investigate the feasibility of an experimental system for simultaneous transcranial DC stimulation(tDCS) and EEG recording in human epilepsy. We report tolerability of this system in a cross-over controlled trial with 15 healthy subjects and preliminary effects of its use, testing repeated tDCS sessions, in two patients with drug-refractory Continuous Spike-Wave Discharges During Slow Sleep (CSWS). Our system combining continuous recording of the EEG with tDCS allows detailed evaluation of the interictal activity during the entire process. Stimulation with 1 mA was well‐tolerated in both healthy volunteers and patients with refractory epilepsy. The large reduction in interictal epileptiform EEG discharges in the two subjects with epilepsy supports further investigation of tDCS using this combined method of stimulation and monitoring in epilepsy. Continuous monitoring of epileptic activity throughout tDCS improves safety and allows detailed evaluation of epileptic activity changes induced by tDCS in patients.
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BACKGROUND: Prospective testing for posttransplant circulating anti-HLA antibodies seems to be a critical noninvasive tool, but confirmatory data are lacking. MATERIALS AND METHODS: Over the last 3 years, peritubular capillary (PTC) C4d deposition was prospectively sought by an immunofluorescence technique applied to frozen tissue in biopsies obtained for allograft dysfunction. Screening for circulating anti-HLA class I/II alloantibodies (AlloAb) by the flow cytometric test was performed simultaneously. RESULTS: We evaluated 132 sets of biopsies and simultaneous serum samples. PTC C4d deposition was demonstrated in 15.9% (21/132) of biopsies. Circulating anti-HLA I/II AlloAb were detected in 25% (33/132) of serum samples. Employing receiver-operator characteristic (ROC) curves for all C4d-positive biopsies, screening for AlloAb showed a global specificity of 82% and sensitivity of 61.9%. When this analysis was restricted to biopsies obtained in the first month posttransplantation, the sensitivity increased to 81.8%, but the specificity decreased to 76.9%. After the first month posttransplantation, we observed sensitivity of 40.0% and a specificity of 86.4%. In the first month posttransplantation, all patients with a diagnosis of acute antibody-mediated rejection displayed circulating anti-HLA class I/II, but not always at the same time as the C4d-positive biopsy. CONCLUSIONS: In the first month posttransplantation, prospective monitoring of anti-HLA antibodies may be useful. The high sensitivity allows the identification of patients at risk, affording an earlier diagnosis of antibody-mediated rejection. After the first month, the test can be used to evaluate allograft dysfunction episodes, since positivity is highly suggestive of an antibody-mediated process.
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Dissertação para obtenção do Grau de Doutor em Bioengenharia
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Until this day, the most efficient Cu(In,Ga)Se2 thin film solar cells have been prepared using a rather complex growth process often referred to as three-stage or multistage. This family of processes is mainly characterized by a first step deposited with only In, Ga and Se flux to form a first layer. Cu is added in a second step until the film becomes slightly Cu-rich, where-after the film is converted to its final Cu-poor composition by a third stage, again with no or very little addition of Cu. In this paper, a comparison between solar cells prepared with the three-stage process and a one-stage/in-line process with the same composition, thickness, and solar cell stack is made. The one-stage process is easier to be used in an industrial scale and do not have Cu-rich transitions. The samples were analyzed using glow discharge optical emission spectroscopy, scanning electron microscopy, X-ray diffraction, current–voltage-temperature, capacitance-voltage, external quantum efficiency, transmission/reflection, and photoluminescence. It was concluded that in spite of differences in the texturing, morphology and Ga gradient, the electrical performance of the two types of samples is quite similar as demonstrated by the similar J–V behavior, quantum spectral response, and the estimated recombination losses.
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The development and application of a polyaniline/carbon nanotube (CNT) cyclodextrin matrix (PANI-β-CD/MWCNT)-based electrochemical sensor for the quantitative determination of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) and its main transformation product 4-chloro-2-methylphenol in natural waters are described. A simple cyclic voltammetry-based electrochemical methodology, in phosphate buffer solution at pH 6.0, was used to develop a method to determine both MCPA and 4-chloro-2-methylphenol, without any previous extraction or derivatization steps. A linear concentration range (10 to 50 μmol L−1) and detection limits of 1.1 and 1.9 μmol L−1, respectively, were achieved using optimized cyclic voltammetric parameters. The proposed method was successfully applied to the determination of MCPA and 4-chloro-2-methylphenol in natural water samples with satisfactory recoveries (94 to 107 %) and in good agreement with the results obtained by an established high-performance liquid chromatography technique, no significant differences being found between the methods. Interferences from ionic species and other herbicides used for broad-leaf weed control were shown to be small. The newly developed methodology was also successfully applied to MCPA photodegradation environmental studies.
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In this work, kriging with covariates is used to model and map the spatial distribution of salinity measurements gathered by an autonomous underwater vehicle in a sea outfall monitoring campaign aiming to distinguish the effluent plume from the receiving waters and characterize its spatial variability in the vicinity of the discharge. Four different geostatistical linear models for salinity were assumed, where the distance to diffuser, the west-east positioning, and the south-north positioning were used as covariates. Sample variograms were fitted by the Mat`ern models using weighted least squares and maximum likelihood estimation methods as a way to detect eventual discrepancies. Typically, the maximum likelihood method estimated very low ranges which have limited the kriging process. So, at least for these data sets, weighted least squares showed to be the most appropriate estimation method for variogram fitting. The kriged maps show clearly the spatial variation of salinity, and it is possible to identify the effluent plume in the area studied. The results obtained show some guidelines for sewage monitoring if a geostatistical analysis of the data is in mind. It is important to treat properly the existence of anomalous values and to adopt a sampling strategy that includes transects parallel and perpendicular to the effluent dispersion.
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In this paper we present ezGo, an electric powered wheelchair with a speech based interface and biosignal monitoring instrumentation. The user can use the voice, a natural communication method, for controlling the chair movement and obtain information about his health. Additionally a set of semi-autonomous modes with macro recording enable the execution of navigation tasks with little effort and improved precision. The main purpose of the system is to provide severely disabled persons with an assistive device that can improve their confidence and daily independence. The obtained results on usability tests showed that users consider ezGo a valuable help on their daily tasks and a very desirable addition to standard wheelchairs.
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We report a primary response to Toxoplasma gondii following a hematopoietic stem cell transplantation in a patient with multiple myeloma. The primary response to T. gondii was supported by IgM, IgG and IgA seroconversion. The patient was promptly treated and there were no complications related to toxoplasmosis in the subsequent months.
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Malaria is an unusual complication after hematopoietic stem cell transplantation in non-endemic countries. However, transplant candidates, recipients and donors living in endemic regions frequently report previous episodes of malaria. This fact could represent an important risk for immunosuppressed recipients that could develop severe malaria cases. We report a case of hematopoietic stem cell transplant (HSCT) in which the donor had a history of previous malaria, and close monitoring was performed before and after procedure by parasitological and molecular tests. The donor presented Plasmodium vivax in thick blood smears one month after transplant and was treated according to Brazilian Health Ministry guidelines. The polymerase chain reaction (PCR) was able to detect malaria infection in the donor one week earlier than thick blood film. Even without positive results, the recipient was pre-emptively treated with chloroquine in order to prevent the disease. We highlight the importance of monitoring recipients and donors in transplant procedures with the aim of reducing the risk of malaria transmission.
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Esta investigação surgiu da identificação de dificuldades ao nível da interação e gestão de conflitos entre pares, que a investigadora teve a oportunidade de observar no grupo de crianças com quem desenvolvia a sua prática educativa. Este estudo tem como objetivo compreender de que forma a transformação da praxis do educador influencia os processos de prevenção e a mediação dos conflitos entre pares no jardim-de-infância. Tendo em conta as formas e as características das relações entre pares na infância bem como o desenvolvimento moral das crianças em idade préescolar, a investigadora levou a cabo um projeto de investigação-ação com um grupo de vinte e quatro crianças de cinco anos. Ao longo do projeto, a investigadora procurou conhecer e experimentar estratégias de prevenção e mediação de conflitos interpares, monitorizando esse processo através da reflexão sobre a ação, assim como compreender os efeitos dessa experimentação no desenvolvimento profissional e na aprendizagem das crianças. Os processos do projeto são apresentados através de uma descrição densa dos eixos centrais da ação: construção do quadro de regras, organização do tempo e do grupo, organização do espaço e dos materiais, experimentação de instrumentos de pilotagem, reunião de grande grupo e estratégias de resolução de conflitos. Os dados apresentados resultam da interpretação das categorias emergentes da análise das entrevistas e das notas de campo. Através dessa interpretação, foi possível constatar os efeitos positivos do projeto, não apenas ao nível das competências de escuta e de negociação das crianças, mas também para a prática profissional da investigadora, que desenvolveu competências de reflexão e de autossupervisão.
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O maior desafio da escola atual é conjugar a escolaridade obrigatória e universal com a ânsia do sucesso educativo. Uma escola justa e democrática não pode limitar-se a selecionar os que têm mais mérito, tem, obrigatoriamente, de se preocupar com aqueles que têm mais dificuldades em ter sucesso e que se vão autoexcluindo. Um dos dispositivos clássicos para potenciar os resultados académicos são os Apoios Educativos, porém no Agrupamento de Escolas X, um Território Educativo de Intervenção Prioritária (TEIP), os resultados obtidos mantêm-se abaixo dos padrões nacionais. É este o ponto de partida do nosso estudo, pois, apesar do investimento considerável no aumento de apoios educativos neste Agrupamento, muitos alunos continuam a registar insucesso educativo.Partindo desta realidade percecionada com a análise documental sobre os Apoios Educativos neste Agrupamento, e após uma ação de acompanhamento da Inspeção Geral da Educação e Ciência, surgiu a necessidade de orientar o nosso olhar para uma análise de todo o processo dos apoios de modo a perceber como se pode otimizar o impacto dos apoios no sucesso dos alunos e, consequentemente, ter o reconhecimento exterior. Tendo por base a análise de conteúdo das entrevistas a docentes de Português e Matemática, envolvidos no processo dos apoios educativos e do focus group realizado com alunos que beneficiaram destes apoios educativos, e suportada por um enquadramento teórico e legal, delineou-se um plano de ação, que visa a melhoria do sucesso educativo de todos os alunos e envolve toda a organização escolar. Perceciona-se a preponderância da coordenação e da monitorização num processo que se pretende efetivo e não de simples receituário, mas acima de tudo, toma-se consciência que para funcionar é necessário que seja devidamente clarificado, sentido e apropriado por todos os atores envolvidos.
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No decurso deste projeto, procurou-se através do desenvolvimento de um processo de investigação-ação, efetuar mudanças em dois níveis, tendo sido o primeiro em prol da minoração de debilidades na aprendizagem previamente diagnosticadas num Agrupamento de Escolas, e o segundo visando uma transformação de hábitos enraizados, inerentes à cultura organizacional da comunidade escolar que compõe este Agrupamento. Desta forma, pretendeu-se a compreensão de determinadas situações que se constituíam, na aceção do investigador, como problemáticas sob determinados aspetos e suscetíveis de mudança, exigindo uma resposta prática. Face a isto, procurou-se construir um projeto realista porém ambicioso, assente em lógicas e teorias validadas e enquadrado nas especificidades de um Agrupamento de Escolas. Ao longo do trajeto, recorreu-se a uma série de procedimentos, designadamente de investigação, planeamento, ação, negociação, mudança, monitorização, análise e reformulação. Espera-se e deseja-se que os procedimentos levados a termo surtam os efeitos para os quais foram delineados e que perdurem, particularmente, na cultura organizacional que integra o Agrupamento, embora ciente que as mudanças efetivas nem sempre se produzem em espaços temporais definidos à partida.
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A pilot study aimed to introduce intraoperative monitoring of liver surgery using transoesophageal echocardiography (TEE) is described. A set of TEE measurements was established as a protocol, consisting of left atrial (LA) dimension at the aortic valve plane; mitral velocity flow integral, calculation of stroke volume and cardiac output (CO); mitral annular plane systolic excursion; finally, right atrial area. A total of 165 measurements (on 21 patients) were performed, 31 occurring during hypotension. The conclusions reached were during acute blood loss LA dimension changed earlier than CVP, and, in one patient, a dynamic left ventricular (LV) obstruction was observed; in 3 patients a transient LV systolic dysfunction was documented. The comparison between 39 CO paired measurements obtained by TEE and PiCCO2 revealed a statistically significant correlation (P < 0.001, r = 0.83). In this pilot study TEE successfully answered the questions raised by the anesthesiologists. Larger cohort studies are needed to address this issue.