914 resultados para Combined Heat and Power (CHP)


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Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, perfil Gestão e Sistemas Ambientais

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Research on Parkinson’s disease (PD) has mainly focused on the degeneration of the dopaminergic neurons of nigro-striatal (NS) pathway; also, post-mortem studies have demonstrated that the noradrenergic and the serotonergic transmitter systems are also affected (Jellinger, 1999). Degeneration of these neuronal cell bodies is generally thought to start prior to the loss of dopaminergic neurons in the NS pathway and precedes the appearance of the motor symptoms that are the “hallmark” of PD. Gastrointestinal (GI) motility is often disturbed in PD, manifesting chiefly as impaired gastric emptying and constipation. These GI dysfunction symptoms may be the result of a loss in noradrenergic and serotonergic innervation. GI deficits were evaluated using an organ bath technique. Groups treated with different combinations of neurotoxins (6-OHDA alone, 6-OHDA + pCA or 6-OHDA + DSP-4) presented significant differences in gut contractility compared to control groups. Since a substantial body of literature suggests the presence of an inflammatory process in parkinsonian state (Whitton, 2007), changes in pro-inflammatory cytokines in the gut were assessed using a cytokine microarray. It has been found in this work that groups with a combined dopaminergic and noradrenergic lesion have a significant increase in both expressions of IL-13 and VEGF. IL-6 also shows a decrease in treatment groups; however this decrease did not reach statistical significance. The therapeutic value of Exendin-4 (EX-4) was evaluated. It has been previously demonstrated that EX-4, a glucagon-like peptide-1 receptor (GLP-1R) agonist, is neuroprotective in rodent models of PD (Harkavyi et al., 2008). In this thesis it has been found that EX-4 was able to reverse a decrease in gut contractility obtained through intracerebral bilateral 6-OHDA injection. Although more studies are required, EX-4 could be used as a possible therapy for the GI symptoms prominent in the early stages of PD.

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ABSTRACT - Background: Integration of health care services is emerging as a central challenge of health care delivery, particularly for patients with elderly and complex chronic conditions. In 2003, the World Health Organization (WHO) already began to identify it as one of the key pathways to improve primary care. In 2005, the European Commission declared integrated care as vital for the sustainability of social protection systems in Europe. Nowadays, it is recognized as a core component of health and social care reforms across European countries. Implementing integrated care requires coordination between settings, organizations, providers and professionals. In order to address the challenge of integration in such complex scenario, an effective workforce is required capable of working across interdependent settings. The World Health Report 2006 noted that governments should prepare their workforce and explore what tasks the different levels of health workers are trained to do and are capable of performing (skills mix). Comparatively to other European countries, Portugal is at an early stage in what integrated care is concerned facing a growing elderly population and the subsequent increase in the pressure on institutions and professionals to provide social and medical care in the most cost-effective way. In 2006 the Portuguese government created the Portuguese Network for Integrated Care Development (PNICD) to solve the existing long-term gap in social support and healthcare. On what concerns health workforce, the Portuguese government already recognized the importance of redefine careers keeping professional motivation and satisfaction. Aim of the study: This study aims to contribute new evidence to the debate surrounding integrated care and skills mix policies in Europe. It also seeks to provide the first evidence that incorporates both the current dynamics of implementing integrated care in Portugal and the developments of international literature. The first ambition of our study is to contribute to the growing interest in integrated care and to the ongoing research in this area by identifying its different approaches and retrieve a number of experiences in some European countries. Our second goal of this research is to produce an update on the knowledge developed on skills mix to the international healthcare management community and to policy makers involved in reforming healthcare systems and organizations. To better inform Portuguese health policies makers in a third stage we explore the current dynamics of implementing integrated care in Portugal and contextualize them with the developments reported in the international literature. Methodology: This is essentially an exploratory and descriptive study using qualitative methodology. In order to identify integrated care approaches in Europe, a systematic literature review was undertaken which resulted in a paper published in the Journal of Management and Marketing in Health care titled: Approaches to developing integrated care in Europe: a systematic literature review. This article was recommended and included into a list of references identified by The King's Fund Library. A second systematic literature review was undertaken which resulted in a paper published in the International Journal of Healthcare Management titled: Skills mix in healthcare: An international update for the management debate. Semi-structured interviews were performed on experts representing the regional coordination teams of the Portuguese Network for Integrated Care Development. In a last stage a questionnaire survey was developed based on the findings of both systematic literature reviews and semi-structured interviews. Conclusions: Even though integrated care is a worldwide trend in health care reforms, there is no unique definition. Definitions can be grouped according to their sectorial focus: community-based care, combined health and social care, combined acute and primary care, the integration of providers, and in a more comprehensive approach the whole health system. Indeed, models that seek to apply the principles of integrated care have a similar background and are continually evolving and depend on the different initiatives taken at national level. . Despite the fact that we cannot argue that there is one single set typology of models for integrated care, it is possible to identify and categorize some of the basic approaches that have been taken in attempts to implement integrated care according to: changes in organizational structure, workforce reconfiguring, and changes in the financing system. The systematic literature review on skills mix showed that despite the widely acknowledged interest on skills mix initiatives there is a lack of evidence on skills mix implications, constraints, outcomes, and quality impact that would allow policy makers to take sustained and evidence-based decisions. Within the Portuguese health system, the integrated care approach is rather organizational and financial, whereas little attention is given to workforce integration. On what concerns workforce planning Portugal it is still in the stage of analyzing the acceptability of health workforce skills mix. In line with the international approaches, integration of health and social services and bridging primary and acute care are the main goals of the national government strategy. The findings from our interviews clarify perceptions which show no discrepancy with the related literature but are rather scarce comparing to international experience. Informants hold a realistic but narrow view of integrated care related issues. They seem to be limited to the regional context, requiring a more comprehensive perspective. The questionnaire developed in this thesis is an instrument which, when applied, will allow policy makers to understand the basic set of concepts and managerial motivations behind national and regional integrated care programs. The instrument developed can foster evidence on the three essential components of integrated care policies: organizational, financial, and human resources development, and can give additional input on the context in which integrated care is being developed, the type of providers and organizations involved, barriers and constraints, and the workforce skills mix planning related strategies. The thesis was successful in recognizing differences between countries and interventions and the instrument developed will allow a better comprehension of the international options available and how to address the vital components of integrated care programs.

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INTRODUCTION: Exclusive or associated lesions in various structures of the autonomic nervous system occur in the chronic forms of Chagas disease. In the indeterminate form, the lesions are absent or mild, whereas in the exclusive or combined heart and digestive disease forms, they are often more pronounced. Depending on their severity these lesions can result mainly in cardiac parasympathetic dysfunction but also in sympathetic dysfunction of variable degrees. Despite the key autonomic effect on cardiovascular functioning, the pathophysiological and clinical significance of the cardiac autonomic dysfunction in Chagas disease remains unknown. METHODS: Review of data on the cardiac autonomic dysfunction in Chagas disease and their potential consequences, and considerations supporting the possible relationship between this disturbance and general or cardiovascular clinical and functional adverse outcomes. RESULTS: We hypothesise that possible consequences that cardiac dysautonomia might variably occasion or predispose in Chagas disease include: transient or sustained arrhythmias, sudden cardiac death, adverse overall and cardiovascular prognosis with enhanced morbidity and mortality, an inability of the cardiovascular system to adjust to functional demands and/or respond to internal or external stimuli by adjusting heart rate and other hemodynamic variables, and immunomodulatory and cognitive disturbances. CONCLUSIONS: Impaired cardiac autonomic modulation in Chagas disease might not be a mere epiphenomenon without significance. Indirect evidences point for a likely important role of this alteration as a primary predisposing or triggering cause or mediator favouring the development of subtle or evident secondary cardiovascular functional disturbances and clinical consequences, and influencing adverse outcomes.

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The Electrohysterogram (EHG) is a new instrument for pregnancy monitoring. It measures the uterine muscle electrical signal, which is closely related with uterine contractions. The EHG is described as a viable alternative and a more precise instrument than the currently most widely used method for the description of uterine contractions: the external tocogram. The EHG has also been indicated as a promising tool in the assessment of preterm delivery risk. This work intends to contribute towards the EHG characterization through the inventory of its components which are: • Contractions; • Labor contractions; • Alvarez waves; • Fetal movements; • Long Duration Low Frequency Waves; The instruments used for cataloging were: Spectral Analysis, parametric and non-parametric, energy estimators, time-frequency methods and the tocogram annotated by expert physicians. The EHG and respective tocograms were obtained from the Icelandic 16-electrode Electrohysterogram Database. 288 components were classified. There is not a component database of this type available for consultation. The spectral analysis module and power estimation was added to Uterine Explorer, an EHG analysis software developed in FCT-UNL. The importance of this component database is related to the need to improve the understanding of the EHG which is a relatively complex signal, as well as contributing towards the detection of preterm birth. Preterm birth accounts for 10% of all births and is one of the most relevant obstetric conditions. Despite the technological and scientific advances in perinatal medicine, in developed countries, prematurity is the major cause of neonatal death. Although various risk factors such as previous preterm births, infection, uterine malformations, multiple gestation and short uterine cervix in second trimester, have been associated with this condition, its etiology remains unknown [1][2][3].

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Quadrature oscillators are key elements in modern radio frequency (RF) transceivers and very useful nowadays in wireless communications, since they can provide: low quadrature error, low phase-noise, and wide tuning range (useful to cover several bands). RC oscillators can be fully integrated without the need of external components (external high Q-inductors), optimizing area, cost, and power consumption. The conventional structure of ring oscillator offers poor frequency stability and phasenoise, low quality factor (Q), and besides being vulnerable to process, voltage and temperature (PVT) variations, its performance degrades as the frequency of operation increases. This thesis is devoted to quadrature oscillators and presents a detailed comparative study of ring oscillator and shift register (SR) approaches. It is shown that in SRs both phase-noise and phase error are reduced, while ring oscillators have the advantage of occupying less area and less consumption due to the reduced number of components in the circuit. Thus, although ring oscillators are more suitable for biomedical applications, SRs are more appropriate for wireless applications, especially when specification requirements are more stringent and demanding. The first architecture studied consists in a simple CMOS ring oscillator employing an odd number of static single-ended inverters as delay cells. Subsequently, the quadrature 4-stage ring oscillator concept is shown and post-layout simulations are presented. The 3 and 4-phase single-frequency local oscillator (LO) generators employing SRs are presented, the latter with 50% and 25% duty-cycles. The circuits operate at 600 MHz and 900 MHz, and were designed in a 130 nm standard CMOS technology with a voltage supply of 1.2 V.

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Necrotizing enterocolitis is a disease of the newborn that may involve the small intestine and/or the colon, and the stomach. To our knowledge, massive necrosis of the small intestine with concomitant involvement of the esophagus has never been reported. A case of a 6-month-old boy with necrotizing enterocolitis and pan-necrosis of the small intestine, cecum, and the lower third of the esophagus is presented. After 70 days of treatment, intestinal transit was established by an anastomosis between the first centimeter of jejunum and the ascending colon. Finally, esophageal transit was established by a total gastric transposition with cervical esophagogastric anastomosis. The patient was maintained under total parenteral nutrition, and after 19 months he developed fulminant hepatic failure due to parenteral nutrition; he then underwent combined liver and small bowel transplantation. After 2 months, the patient died due to undefined neurologic complications, probably related to infection or immunosuppressive therapy.

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This paper presents a comprehensive comparison of a current-source converter and a voltage-source converter for three-phase electric vehicle (EV) fast battery chargers. Taking into account that the current-source converter (CSC) is a natural buck-type converter, the output voltage can assume a wide range of values, which varies between zero and the maximum instantaneous value of the power grid phase-to-phase voltage. On the other hand, taking into account that the voltage-source converter (VSC) is a natural boost-type converter, the output voltage is always greater than the maximum instantaneous value of the power grid phase-to-phase voltage, and consequently, it is necessary to use a dc-dc buck-type converter for applications as EV fast battery chargers. Along the paper is described in detail the principle of operation of both the CSC and the VSC for EV fast chargers, as well as the main equations of the power theory and current control strategies. The comparison between both converters is mainly established in terms of the total harmonic distortion of the grid current and the estimated efficiency for a range of operation between 10 kW and 50 kW.

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This paper presents the proposal of a three phase current source shunt active power filter (CS-SAPF) with photovoltaic grid interface. The proposed system combines the compensation of reactive power and harmonics with the injection of energy from a solar photovoltaic array into the electrical power grid. The proposed equipment presents the advantage of giving good use to the current source inverter, even when the solar photovoltaic array is not producing energy. The paper describes the control system of the CS SAPF, the energy injection control strategy, and the current harmonics and power factor compensation strategy. Simulation results to assess the performance of the proposed system are also presented.

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Discussing urban planning requires rethinking sustainability in cities and building healthy environments. Historically, some aspects of advancing the urban way of life have not been considered important in city planning. This is particularly the case where technological advances have led to conflicting land use, as with the installation of power poles and building electrical substations near residential areas. This research aims to discuss and rethink sustainability in cities, focusing on the environmental impact of low-frequency noise and electromagnetic radiation on human health. It presents data from a case study in an urban space in northern Portugal, and focuses on four guiding questions: Can power poles and power lines cause noise? Do power poles and power lines cause discomfort? Do power poles and power lines cause discomfort due to noise? Can power poles and power lines affect human health? To answer these questions, we undertook research between 2014 and 2015 that was comprised of two approaches. The first approach consisted of evaluating the noise of nine points divided into two groups â near the sourceâ (e.g., up to 50 m from power poles) and â away from the sourceâ (e.g., more than 250 m away from the source). In the second approach, noise levels were measured for 72 h in houses located up to 20 m from the source. The groups consist of residents living within the distance range specified for each group. The measurement values were compared with the proposed criteria for assessing low-frequency noise using the DEFRA Guidance (University of Salford). In the first approach, the noise caused discomfort, regardless of the group. In the second approach, the noise had fluctuating characteristics, which led us to conclude that the noise caused discomfort.

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Purpose: To study the relationship among the variables intensity ofthe end-of-day (EOD) dryness, corneal sensitivity and blink rate in soft contact lens (CL) wearers. Methods: Thirty-eight soft CL wearers (25 women and 13 men; mean age 27.1 ± 7.2 years) were enrolled. EOD dryness was assessed using a scale of 0–5 (0, none to 5, very intense). Mechanical and thermal (heat and cold) sensitivity were measured using a Belmonte’s gas esthesiometer. The blink rate was recorded using a video camera while subjects were wearing a hydrogel CL and watching a film for 90 min in a controlled environmental chamber. Results: A significant inverse correlation was found between EOD dryness and mechanical sensitivity (r: −0.39; p = 0.02); however, there were no significant correlations between EOD dryness and thermal sensitivity. A significant (r: 0.56; p < 0.001) correlation also was observed between EOD dryness and blink rate, but no correlations were found between blink rate and mechanical or thermal sensitivity. Conclusions: CL wearers with higher corneal sensitivity to mechanical stimulation reported more EOD dryness with habitual CL wear. Moreover, subjects reporting more EOD dryness had an increased blink rates during wear of a standard CL type. The increased blink rate could act to improve the ocular surface environment and relieve symptoms

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Dissertação mestrado em Biologia Molecular, Biotecnologia e Bioempreendedorismo em Plantas

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Tese de Doutoramento em Engenharia de Materiais.

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Tese de Doutoramento em Ciência Política e Relações Internacionais

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Tese de Doutoramento (Programa Doutoral em Engenharia Biomédica)