970 resultados para optimal machining parameters
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O diagnóstico da malária é realizado rotineiramente pelo exame da gota espessa, entretanto, esta técnica requer o treinamento de microscopistas e pode consumir muito tempo. Foi realizado um estudo de concordância de dois testes rápidos (Optimal-IT® e ICT P.f./P.v.®) com a gota espessa, na atenção básica de saúde, em Manaus.
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INTRODUCTION: Discrepancy between the intensity of pulmonary congestion and the grade of cardiomegaly seems to be a common finding of Chagas cardiomyopathy, in spite of significant systolic dysfunction of the left ventricle. Its mechanism has not been established. The aim of this study was to investigate pulmonary congestion and to analyze if it correlated with Doppler echocardiographic parameters in patients with Chagas dilated cardiomyopathy. METHODS: Fifty-five patients with positive serology tests for Trypanosoma cruzi and Chagas dilated cardiomyopathy were studied. Chest x-rays, Doppler echocardiogram and plasmatic brain natriuretic peptide levels were obtained in all patients. The degree of pulmonary venous vessels changes on chest x-ray was graded using a pulmonary congestion score, and then compared to Doppler echocardiographic parameters. RESULTS: Mean age was 48.5 ± 11.2 years and 29% were women. The majority (95%) of patients were in NYHA functional class I and II. Mild pulmonary congestion by chest x-ray was found in 80% of the patients. In a multivariate analysis, left ventricular ejection fraction, right ventricular TEI index and the color M-mode velocity correlated with the degree of pulmonary congestion. CONCLUSIONS: Pulmonary venous changes on chest x-rays are frequent, but usually mild in patients with Chagas dilated cardiomyopathy. The degree of pulmonary congestion correlates with Doppler echocardiographic left and right ventricular dysfunction and with color M-mode velocity.
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With the recent advances in technology and miniaturization of devices such as GPS or IMU, Unmanned Aerial Vehicles became a feasible platform for a Remote Sensing applications. The use of UAVs compared to the conventional aerial platforms provides a set of advantages such as higher spatial resolution of the derived products. UAV - based imagery obtained by a user grade cameras introduces a set of problems which have to be solved, e. g. rotational or angular differences or unknown or insufficiently precise IO and EO camera parameters. In this work, UAV - based imagery of RGB and CIR type was processed using two different workflows based on PhotoScan and VisualSfM software solutions resulting in the DSM and orthophoto products. Feature detection and matching parameters influence on the result quality as well as a processing time was examined and the optimal parameter setup was presented. Products of the both workflows were compared in terms of a quality and a spatial accuracy. Both workflows were compared by presenting the processing times and quality of the results. Finally, the obtained products were used in order to demonstrate vegetation classification. Contribution of the IHS transformations was examined with respect to the classification accuracy.
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Author's Pre-print
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INTRODUCTION: Despite significant left ventricular (LV) systolic dysfunction and cardiomegaly, pulmonary congestion does not seem to be a major finding in Chagas' cardiomyopathy (CC). This study sought to identify echocardiographic parameters associated with pulmonary congestion in CC and in dilated cardiomyopathy of other etiologies, such as non-CC (NCC), and to compare pulmonary venous hypertension between the two entities. METHODS: A total of 130 consecutive patients with CC and NCC, with similar echocardiographic characteristics, were assessed using Doppler echocardiography and chest radiography. Pulmonary venous vessel abnormalities were graded using a previously described pulmonary congestion score, and this score was compared with Doppler echocardiographic parameters. RESULTS: NCC patients were older than CC patients (62.4 ± 13.5 × 47.8 ± 11.2, p = 0.00), and there were more male subjects in the CC group (66.2% × 58.5%, p = 0.4). Pulmonary venous hypertension was present in 41 patients in the CC group (63.1%) and in 63 (96.9%) in the NCC group (p = 0.0), the mean lung congestion score being 3.2 ± 2.3 and 5.9 ± 2.6 (p = 0.0), respectively. On linear regression multivariate analysis, the E/e' ratio (β = 0.13; p = 0.0), LV diastolic diameter (β = 0.06; p = 0.06), left atrial diameter (β = 0.51; p = 0.08), and right ventricular (RV) end-diastolic diameter (β = 0.02; p = 0.48) were the variables that correlated with pulmonary congestion in both groups. CONCLUSIONS: Pulmonary congestion was less significant in patients with CC. The degree of LV of systolic and diastolic dysfunction and the RV diameter correlated with pulmonary congestion in both groups. The E/e' ratio was the hallmark of pulmonary congestion in both groups.
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An infinite-horizon discrete time model with multiple size-class structures using a transition matrix is built to assess optimal harvesting schedules in the context of Non-Industrial Private Forest (NIPF) owners. Three model specifications accounting for forest income, financial return on an asset and amenity valuations are considered. Numerical simulations suggest uneven-aged forest management where a rational forest owner adapts her or his forest policy by influencing the regeneration of trees or adjusting consumption dynamics depending on subjective time preference and market return rate dynamics on the financial asset. Moreover she or he does not value significantly non-market benefits captured by amenity valuations relatively to forest income.
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Although modern combined antiretroviral therapies (cART) result in lower morbidity and mortality and a visible improvement of clinical and laboratory parameters in HIV-infected, it is known that their long-term use contributes to appearance of the many events unrelated to AIDS such as cardiovascular diseases, cancer and osteoporosis, comorbidities which have been proposed as some of the most important that deprive the majority of infected to present an even better prognosis. This is because even with a decrease in inflammation and immune activation after drug intervention to the patient, these parameters remain higher than those shown by healthy individuals and the imbalance of cytokine profiles also persists. Therefore, evaluations of other biomarkers in clinical practice are needed to complement the exams already carried out routinely and allow more effective monitoring of HIV patients. This review aims to investigate the role of cytokines as potential markers showing studies on their behavior in various stages of HIV infection, with or without cART.
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In modern society, energy consumption and respect for the environment have become essential aspects of urban planning. The rising demand for alternative sources of energy, coupled with the decline in the construction sector and material usage, gives the idea that the thinking on modern cities, where attention is given to reduced energy consumption, savings, waste recycling and respect for the surrounding environment, is being put into practice. If we examine development of the city over recent centuries, by means of the theories of the most famous and influential urban planners, it is possible to identify the major problems caused by this type of planning. For this reason, in recent urban planning the use of systems of indicators that evaluate and certify land environmentally and energetically guides the master plan toward a more efficient city model. In addition the indicators are targeted on key factors determined by the commissioner or the opportunities the territory itself provides. Due the complexity of the environmental mechanics, the process of design and urban planning has become a challenging issue. The introduction of the indicators system has made it possible to register the life of the process, with a spiral route that allows the design itself to be refined. The aim of this study, built around the creation of a system of urban sustainability indicators that will evaluate highly eco-friendly cities, is to develop a certification system for cities or portions of them. The system will be upgradeable and objective, will employ real data and will be concerned with energy production and consumption.
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The work described in this thesis was performed at the Laboratory for Intense Lasers (L2I) of Instituto Superior Técnico, University of Lisbon (IST-UL). Its main contribution consists in the feasibility study of the broadband dispersive stages for an optical parametric chirped pulse amplifier based on the nonlinear crystal yttrium calcium oxi-borate (YCOB). In particular, the main goal of this work consisted in the characterization and implementation of the several optical devices involved in pulse expansion and compression of the amplified pulses to durations of the order of a few optical cycles (20 fs). This type of laser systems find application in fields such as medicine, telecommunications and machining, which require high energy, ultrashort (sub-100 fs) pulses. The main challenges consisted in the preliminary study of the performance of the broadband amplifier, which is essential for successfully handling pulses with bandwidths exceeding 100 nm when amplified from the μJ to 20 mJ per pulse. In general, the control, manipulation and characterization of optical phenomena on the scale of a few tens of fs and powers that can reach the PW level are extremely difficult and challenging due to the complexity of the phenomena of radiation-matter interaction and their nonlinearities, observed at this time scale and power level. For this purpose the main dispersive components were characterized in detail, specifically addressing the demonstration of pulse expansion and compression. The tested bandwidths are narrower than the final ones, in order to confirm the parameters of these elements and predict the performance for the broadband pulses. The work performed led to additional tasks such as a detailed characterization of laser oscillator seeding the laser chain and the detection and cancelling of additional sources of dispersion.
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Os resultados apresentados no capítulo 2 foram incluídos no artigo Dantas JM, Campelo LM, Duke NEC, Salgueiro CA, Pokkuluri PR (2015) "The structure of PccH from Geobacter sulfurreducens – a novel low reduction potential monoheme cytochrome essential for accepting electrons from an electrode", FEBS Journal, 282, 2215-2231.
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White Color tuning is an attractive feature that Organic Light Emitting Diodes (OLEDs) offer. Up until now, there hasn’t been any report that mix both color tuning abilities with device stability. In this work, White OLEDs (W-OLEDs) based on a single RGB blend composed of a blue emitting N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) doped with a green emitting Coumarin-153 and a red emitting 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM1) dyes were produced. The final device structure was ITO/Blend/Bathocuproine (BCP)/ Tris(8-hydroxyquinolinato)aluminium (Alq3)/Al with an emission area of 0.25 cm2. The effects of the changing in DCM1’s concentration (from 0.5% to 1% wt.) allowed a tuning in the final white color resulting in devices capable of emitting a wide range of tunes – from cool to warm – while also keeping a low device complexity and a high stabilitty. Moreover, an explanation on the optoelectrical behavior of the device is presented. The best electroluminescense (EL) points toward 160 cd/m2 of brightness and 1.1 cd/A of efficiency, both prompted to being enhanced. An Impedance Spectroscopy (IS) analysis allowed to study both the effects of BCP as a Hole Blocking Layer and as an aging probe of the device. Finally, as a proof of concept, the emission was increased 9 and 64 times proving this structure can be effectively applied for general lighting.
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Polysaccharides are gaining increasing attention as potential environmental friendly and sustainable building blocks in many fields of the (bio)chemical industry. The microbial production of polysaccharides is envisioned as a promising path, since higher biomass growth rates are possible and therefore higher productivities may be achieved compared to vegetable or animal polysaccharides sources. This Ph.D. thesis focuses on the modeling and optimization of a particular microbial polysaccharide, namely the production of extracellular polysaccharides (EPS) by the bacterial strain Enterobacter A47. Enterobacter A47 was found to be a metabolically versatile organism in terms of its adaptability to complex media, notably capable of achieving high growth rates in media containing glycerol byproduct from the biodiesel industry. However, the industrial implementation of this production process is still hampered due to a largely unoptimized process. Kinetic rates from the bioreactor operation are heavily dependent on operational parameters such as temperature, pH, stirring and aeration rate. The increase of culture broth viscosity is a common feature of this culture and has a major impact on the overall performance. This fact complicates the mathematical modeling of the process, limiting the possibility to understand, control and optimize productivity. In order to tackle this difficulty, data-driven mathematical methodologies such as Artificial Neural Networks can be employed to incorporate additional process data to complement the known mathematical description of the fermentation kinetics. In this Ph.D. thesis, we have adopted such an hybrid modeling framework that enabled the incorporation of temperature, pH and viscosity effects on the fermentation kinetics in order to improve the dynamical modeling and optimization of the process. A model-based optimization method was implemented that enabled to design bioreactor optimal control strategies in the sense of EPS productivity maximization. It is also critical to understand EPS synthesis at the level of the bacterial metabolism, since the production of EPS is a tightly regulated process. Methods of pathway analysis provide a means to unravel the fundamental pathways and their controls in bioprocesses. In the present Ph.D. thesis, a novel methodology called Principal Elementary Mode Analysis (PEMA) was developed and implemented that enabled to identify which cellular fluxes are activated under different conditions of temperature and pH. It is shown that differences in these two parameters affect the chemical composition of EPS, hence they are critical for the regulation of the product synthesis. In future studies, the knowledge provided by PEMA could foster the development of metabolically meaningful control strategies that target the EPS sugar content and oder product quality parameters.
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Research Masters
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Cell-based approaches in tissue engineering (TE) have been barely explored for the treatment of tendon and ligament (T/L) tissues, requiring the establishment of a widely available cell source with tenogenic potential. As T/L cells are scarce, stem cells may provide a good alternative. Understanding how resident cells behave in vitro, might be useful for recapitulating the tenogenic potential of stem cells for tendon TE applications. Therefore, we propose to isolate and characterize human T/L-derived cells (hTDCs and hLDCs) and compare their regenerative potential with stem cells from adipose tissue (hASCs) and amniotic fluid (hAFSCs)(1). T/L cells were isolated using different procedures and stem cells isolated as described elsewhere(1). Moreover, T/L cells were stimu- lated into the three mesenchymal lineages, using standard differentia- tion media. Cells were characterized for the typical stem cell markers as well as T/L related markers, namely tenascin-C, collagen I and III, decorin and scleraxis, using different complementary techniques such as real time RT-PCR, immunocytochemistry and flow cytometry. No differences were observed between T/L in gene expression and protein deposition. T/L cells were mostly positive for stem ness markers (CD73/CD90/CD105), and have the potential to differentiate towards osteogenesis, chondrogenesis and adipogenesis, demonstrated by the positive staining for AlizarinRed, SafraninO, ToluidineBlue and OilRed. hASCs and hAFSCs exhibit positive expression of all tenogenic mark- ers, although at lower levels than hTDCs and hLDCs. Nevertheless, stem cells availability is key factor in TE strategies, despite that it’s still required optimization to direct their tenogenic phenotype.
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In this research, five types of polymer repair materials were selected for investigation of the influence of sample shape, deformation rate and test temperature on the mechanical properties determined with an uniaxial tensile test. The results showed the clear effect of measurement conditions on tensile strength, elongation and modulus of elasticity. The highest tensile strength and modulus of elasticity were exhibited by epoxy resin for the filling of concrete cracks, which achieved 1% elongation. The lowest coefficient of dispersion characterized the results of tensile test carried out using dumbbell samples at a deformation rate of 50 mm/min. The effect of temperature varied with the material type.