The impact of Sinogram-Affirmed Iterative Reconstruction on patient dose and image quality compared to filtered back projection: a narrative review

Objective: Summarize all relevant findings in published literature regarding the potential dose reduction related to image quality using Sinogram-Affirmed Iterative Reconstruction (SAFIRE) compared to Filtered Back Projection (FBP). Background: Computed Tomography (CT) is one of the most used radiographic modalities in clinical practice providing high spatial and contrast resolution. However it also delivers a relatively high radiation dose to the patient. Reconstructing raw-data using Iterative Reconstruction (IR) algorithms has the potential to iteratively reduce image noise while maintaining or improving image quality of low dose standard FBP reconstructions. Nevertheless, long reconstruction times made IR unpractical for clinical use until recently. Siemens Medical developed a new IR algorithm called SAFIRE, which uses up to 5 different strength levels, and poses an alternative to the conventional IR with a significant reconstruction time reduction. Methods: MEDLINE, ScienceDirect and CINAHL databases were used for gathering literature. Eleven articles were included in this review (from 2012 to July 2014). Discussion: This narrative review summarizes the results of eleven articles (using studies on both patients and phantoms) and describes SAFIRE strengths for noise reduction in low dose acquisitions while providing acceptable image quality. Conclusion: Even though the results differ slightly, the literature gathered for this review suggests that the dose in current CT protocols can be reduced at least 50% while maintaining or improving image quality. There is however a lack of literature concerning paediatric population (with increased radiation sensitivity). Further studies should also assess the impact of SAFIRE on diagnostic accuracy.

An ontology-based representation of an agent-based controlled robotic cell

Dissertação apresentada na Faculdade de Ciência e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores

Aplicação da metodologia SMED numa linha de envernizamento/pintura de revestimentos de cortiça

O presente trabalho visa a redução do tempo de mudança de produção e consequente aumento de produtividade de uma linha de envernizamento/pintura integrada na empresa Amorim Revestimentos SA, unidade S. Paio de Oleiros, que se dedica à produção de pisos flutuantes. Esta necessidade surgiu pelo facto desta linha de produção ser um ponto de estrangulamento do processo produtivo no departamento em que está inserida, devido principalmente à diminuição do tamanho de lotes e aumento da variedade de artigos a produzir. O trabalho envolveu as várias etapas da ferramenta SMED às quais está inerente a aplicação da técnica 5S às máquinas e ferramentas garantindo, assim, o posto de trabalho arrumado, limpo, seguro e com tudo pronto a ser utilizado. Aplicou-se a ferramenta SMED a dois tipos de mudança de acabamento e à mudança de rolo de pintura. Após a implementação desta ferramenta verificou-se uma redução de tempos de 37% (48 para 30 minutos) na mudança de pintura e acabamento de verniz, reduziu-se 25% (32 para 24 minutos) na mudança só de pintura e 13% (46 para 40 minutos) na mudança de rolo de pintura. Estes resultados foram alcançados através da redução do tempo das tarefas externas e internas e transformação das tarefas internas em externas consequentes da aplicação de um conjunto de ações de melhorias. Também foi fundamental a alteração do método de trabalho e a organização geral do posto de trabalho, no que diz respeito à repartição equilibrada das tarefas pelos dois operadores, alteração do sequenciamento das tarefas e aplicação da técnica 5S. As soluções encontradas estão sendo monitorizadas através do registo efectuado pelos operadores e realização de auditorias internas para garantir a perpetuação dos resultados.

Calibration Method for Underwater Visual Ground-Truth System

This work presents an automatic calibration method for a vision based external underwater ground-truth positioning system. These systems are a relevant tool in benchmarking and assessing the quality of research in underwater robotics applications. A stereo vision system can in suitable environments such as test tanks or in clear water conditions provide accurate position with low cost and flexible operation. In this work we present a two step extrinsic camera parameter calibration procedure in order to reduce the setup time and provide accurate results. The proposed method uses a planar homography decomposition in order to determine the relative camera poses and the determination of vanishing points of detected lines in the image to obtain the global pose of the stereo rig in the reference frame. This method was applied to our external vision based ground-truth at the INESC TEC/Robotics test tank. Results are presented in comparison with an precise calibration performed using points obtained from an accurate 3D LIDAR modelling of the environment.

Aplicação da abordagem KAIZEN na produção de artigos de papelaria

No âmbito da unidade curricular Tese/Dissertação do 2ºano do Mestrado em Engenharia Eletrotécnica – Ramo Sistemas e Planeamento Industrial do Instituto Superior de Engenharia do Porto, o presente trabalho descreve o estágio curricular efetuado num projeto industrial de melhoria em parceria com o Kaizen Institute, uma empresa de consultoria operacional. Este projeto foi desenvolvido numa empresa de produção e redistribuição de artigos de papelaria e escritório, a Firmo AVS – Papeis e Papelaria,S.A.. O acordo efetuado entre o Kaizen Institute e a Firmo AVS foi o de promover e incutir a cultura da melhoria continua e da mudança de atitudes e comportamentos por parte dos colaboradores da Firmo, sendo que numa fase inicial o foco do projeto foi o departamento de produção de envelopes, designada por área piloto, expandindo-se posteriormente a metodologia Kaizen aos restantes departamentos. A realização deste projeto teve como objetivo a implementação de conceitos elementares de melhoria continua nomeadamente alguns pilares ou ferramentas do Total Flow Management (TFM) e do Kaizen Management System (KMS) na empresa Firmo, de forma a reduzir ou eliminar desperdícios, incremento do envolvimento dos colaboradores, melhoria da comunicação e trabalho em equipa, estandardização de processos produtivos, criação de normas de trabalho, utilização de ferramentas SMED para a redução de tempos improdutivos e aumento da produtividade. Várias foram as dificuldades presentes no terreno para a implementação destes objetivos mas com as diversas ferramentas e workshops realizados na organização, conseguiu-se o envolvimento de todos os colaboradores da organização e a obtenção de resultados satisfatórios nomeadamente ao nível da comunicação e trabalho em equipa, organização e limpeza dos postos de trabalho, standard work (normalização do trabalho), diminuição do lead time nos processos produtivos e consequente aumento de produtividade.

Lean production in the precast concrete components’ industry

Proceedings IGLC-19, July 2011, Lima, Perú

InOut Project – Doing the things right & doing the right things

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Cryopreservation of Cell Sheets of Adipose Stem Cells: Limitations and Successes

Cell Sheets of hASCs (hASCs-CS) have been previously proposed for wound healing applications(1, 2) and despite the concern for production time reduction, the possibility of having these hASCs-CS off-the-shelf is appealing. The goal of this work was to define a cryopreservation methodology allowing to preserve cells viability and the properties CS matrix. hASCs-CS obtained from three different donors were created in UP-cell thermoresponsive dishes(Nunc, Germany) as previously reported(1,2). Different cryopreservation conditions were considered: i)FBS plus DMSO(5% and10%); ii)0.4M of Trehalose plus DMSO (5% and 10%); iii)cryosolution PLL (Akron Biotech, USA); and iv)vitrification. The cryopreservation effect was first assessed for cellular viability by flow cytometry using 7-AAD, and after dissociating the hASCs-CS with collagenase and trypsin-EDTA 0.25%. The expression (RT-PCR) and deposition (western blot and immunocytochemistry) of collagen type I, laminin and fibronectin, and the organization (TEM) of the extracellular matrix was further assessed before and after hASCs-CS cryopreservation to determine a potential effect of the method over matrix composition and integrity. The obtained results confirmed that cell viability is affected by the cryopreservation methodology, as shown before for different CS(3). Interestingly, the matrix properties were not significantly altered and the typical cell sheetâ s easiness of manipulation for transplantation was not lost.

Estudo do trabalho numa empresa de produção de pneus e implementação de ferramentas Lean

Dissertação de mestrado integrado em Engenharia e Gestão Industrial

Melhoria do processo de tingimento numa empresa têxtil

Dissertação de mestrado em Engenharia e Gestão da Qualidade

Análise de tempos e métodos e implementação de ferramentas lean num sistema produtivo

Dissertação de mestrado em Engenharia Industrial

Development of a thermoelectric generator for the exhaust of a vehicle

Dissertação de mestrado integrado em Engenharia Mecânica

Redução do tempo de montagem final de transformadores CORE através da aplicação de ferramentas LEAN

Dissertação de mestrado em Engenharia Industrial

Brazilian multicenter study on efficacy and tolerability of trandolapril in mild-to-moderate essential arterial hypertension. EMBATHE substudy with ambulatory blood pressure monitoring

OBJECTIVE: A double-blind, placebo-controlled multicenter study involving 34 centers from different Brazilian regions was performed to evaluate the antihypertensive efficacy and tolerability of trandolapril, an angiotensin I converting enzyme inhibitor, in the treatment of mild-to-moderate systemic arterial hypertension. METHODS: Of 262 patients enrolled in this study, 127 were treated with trandolapril 2 mg/day for 8 consecutive weeks, and the remaining 135 patients received placebo for the same period of time. Reduction in blood pressure (BP) and the occurrence of adverse events during this period were evaluated in both groups. RESULTS: Significant reductions in both systolic and diastolic pressures were observed in patients treated with trandolapril when compared with those on placebo. Antihypertensive efficacy was achieved in 57.5% of the patients on trandolapril and in 42% of these normal values of BP were obtained. The efficacy of trandolapril was similar in all centers, regardless of the area of the country. In a subset of 30 patients who underwent ABPM, responders showed a significant hypotensive effect to trandolapril throughout the 24 hour day. The adverse event profile was similar in both trandolapril and placebo groups. CONCLUSION: Our results demonstrate, for the first time in a large group of hypertensive patients from different regions in Brazil, good efficacy and tolerability of trandolapril during treatment of mild-to-moderate essential systemic hypertension.

Strong isomorphism reductions in complexity theory

We give the first systematic study of strong isomorphism reductions, a notion of reduction more appropriate than polynomial time reduction when, for example, comparing the computational complexity of the isomorphim problem for different classes of structures. We show that the partial ordering of its degrees is quite rich. We analyze its relationship to a further type of reduction between classes of structures based on purely comparing for every n the number of nonisomorphic structures of cardinality at most n in both classes. Furthermore, in a more general setting we address the question of the existence of a maximal element in the partial ordering of the degrees.