983 resultados para Mean-Reverting Process


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Recent Advances in Mechanics and Materials in Design

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The study of agent diffusion in biological tissues is very important to understand and characterize the optical clearing effects and mechanisms involved: tissue dehydration and refractive index matching. From measurements made to study the optical clearing, it is obvious that light scattering is reduced and that the optical properties of the tissue are controlled in the process. On the other hand, optical measurements do not allow direct determination of the diffusion properties of the agent in the tissue and some calculations are necessary to estimate those properties. This fact is imposed by the occurrence of two fluxes at optical clearing: water typically directed out of and agent directed into the tissue. When the water content in the immersion solution is approximately the same as the free water content of the tissue, a balance is established for water and the agent flux dominates. To prove this concept experimentally, we have measured the collimated transmittance of skeletal muscle samples under treatment with aqueous solutions containing different concentrations of glucose. After estimating the mean diffusion time values for each of the treatments we have represented those values as a function of glucose concentration in solution. Such a representation presents a maximum diffusion time for a water content in solution equal to the tissue free water content. Such a maximum represents the real diffusion time of glucose in the muscle and with this value we could calculate the corresponding diffusion coefficient.

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Introduction. Fabry disease is a rare metabolic disorder caused by the genetic deficiency of the lysosomal hydrolase alpha-galactosidase A, located on chromosome X. Females with the defective gene are more than carriers and can develop a wide range of symptoms. Nevertheless, disease symptoms generally occur later and are less severe in women than in men. The enzyme deficiency manifests as a glycosphingolipidosis with progressive accumulation of glycosphingolipids and deposit of inclusion bodies in lysosomes giving a myelinlike appearance. Patients and Methods. Records of renal biopsies performed on adults from 1st January 2008 to 31st August 2011, were retrospectively examined at the Renal Pathology Laboratory. We retrieved biopsies diagnosed with Fabry disease and reviewed clinical and laboratory data and pathology findings. Results. Four female patients with a mean age of 49.3±4.5 (44-55) years were identified. The mean proteinuria was 0.75±0.3 g/24h (0.4-1.2) and estimated glomerular filtration rate (CKD EPI equation) was 71±15.7 ml/min/1.73m2 (48-83). Three patients experienced extra-renal organ involvement (cerebrovascular, cardiac, dermatologic, ophthalmologic and thyroid) with distinct severity degrees. Leukocyte α-GAL A activity was below normal range in the four cases but plasma and urinary enzymatic activity was normal. Light microscopy showed predominant vacuolisation of the podocyte cytoplasm and darkly staining granular inclusions on paraffin and plastic-embedded semi-thin sections. Electron microscopy showed in three patients the characteristic myelin-like inclusions in the podocyte cytoplasm and also focal podocyte foot process effacement. In one case the inclusions were also present in parietal glomerular cells, endothelial cells of peritubular capillary and arterioles. Conclusion. Clinical signs and symptoms are varied and can be severe among heterozygous females with Fabry disease. Intracellular accumulation of glycosphingolipids is a characteristic histologic finding of Fabry nephropathy. Since this disease is a potentially treatable condition, its early identification is imperative. We should consider it in the differential diagnosis of any patient presenting with proteinuria and/or chronic kidney disease, especially if there is a family history of kidney disease.

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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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Innovation is recognized by academics and practitioners as an essential competitive enabler for any company to survive, to remain competitive and to grow. Investments in tasks of R&D have not always brought the expected results. But that doesn't mean that the outcomes would not be useful to other companies of the same business area or even from another area. Thus, there is much knowledge already available in the market that can be helpful to some and profitable to others. So, the ideas and expertise can be found outside a company's boundaries and also exported from within. Information, knowledge, experience, wisdom is already available in the millions of the human beings of this planet, the challenge is to use them through a network to produce new ideas and tips that can be useful to a company with less costs. This was the reason for the emergence of the area of crowdsourcing innovation. Crowdsourcing innovation is a way of using the Web 2.0 tools to generate new ideas through the heterogeneous knowledge available in the global network of individuals highly qualified and with easy access to information and technology. So, a crowdsourcing innovation broker is an organization that mediates the communication and relationship between the seekers - companies that aspire to solve some problem or to take advantage of any business opportunity - with a crowd that is prone to give ideas based on their knowledge, experience and wisdom. This paper makes a literature review on models of open innovation, crowdsourcing innovation, and technology and knowledge intermediaries, and discusses this new phenomenon as a way to leverage the innovation capacity of enterprises. Finally, the paper outlines a research design agendafor explaining crowdsourcing innovation brokering phenomenon, exploiting its players, main functions, value creation process, and knowledge creation in order to define a knowledge metamodel of such intermediaries.

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Based on the report for “Project IV” unit of the PhD programme on Technology Assessment (Doctoral Conference) at Universidade Nova de Lisboa (December 2011). This thesis research has the supervision of António Moniz (FCT-UNL and ITAS-KIT) and Michael Decker (Karlsruhe Institute of Technology-ITAS). Other members of the thesis committee are Carlos Alberto da Silva (University of Évora), José Maria de Albuquerque (Institute of Welding and Quality), Lotte Steuten (University of Twente), Mário Forjaz Secca (FCT-UNL) and Nelson Chibeles Martins (FCT-UNL).

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Dissertação para obtenção do Grau de Mestre em Engenharia e Gestão Industrial

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Dissertação para obtenção do Grau de Mestre em Biotecnologia

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Background: Approximately 5% of the population donates blood each year in developed countries. Recruiting and maintaining a pool of altruistic and healthy blood donors is a challenging task. Blood donation as a dynamic process must naturally co-exist with the arguably essential deferrals. Aims: To analyse a 11-year cohort of donors and blood donations in order to determine the profile of the average donor and the typical donation. Characterize the donor’s population in terms of gender, age, number of donations, most common causes for deferral and exclusion and the possible relationships between them. Establish the tendency flow of donations per year. Methods: Analysis of 95861 blood donations from 31550 donors collected between 2000 and 2010 (11 years) in the Immunohemotherapy Department of the ‘‘Centro Hospitalar Lisboa Central - Hospital de Sa˜o Jose´’’ (Lisboa, Portugal). Prior to blood donation, donors were required to fill out a form of informed consent, a questionnaire of 21 ‘‘yes or no’’ questions and were submitted to a clinical assessment and physical examination including: measurement of weight, blood pressure, pulse and capillary hemoglobin levels. Post-donation, the collected blood was tested for ALT elevation and blood-borne viral agents (HBV, HCV, HIV 1 and 2 and HTLV 1 and 2) and other infections (Treponema pallidum). Blood donors and donations were registered in a database and statistically studied in terms of: gender and age distribution, number of donations, most common causes for deferral and exclusion. The frequency of blood donations throughout the period of observation was analyzed and statistically significant relationships between the collected variables were investigated. Results: From the population of 31550 donors 61% were male and a mean age of 41.5 years (± 12.5 years) was found. From the total of 95682 blood donations collected 78% were successful while the most common causes for deferral were: donation incompatible hemoglobin levels (5% of the blood donations and 22% of deferrals), ALT elevation (3% and 14%), positive blood screening test for Treponema pallidum (1% and 6%), medication (1% and 4%), positive serological blood markers for HBV (1% and 4%), endoscopy in the previous 12 months (1% and 3%), arterial hypertension (1% and 3%), infectious conditions (1% and 3%), influenza or influenza-like symptoms (1% and 2%) and positive serological blood markers for HCV (1% and 2%). Summary/Conclusions: Several factors may have contributed to a limited number of new regular donors in the population, namely: ageing population, the alienation of the individual from the community induced by modern lifestyles and job precariousness. It is of the utmost importance to refine our blood donation campaigns according to the existing population of donors. The optimization of the blood donation potential of a population of donors must be achieved through the development of reliable and consistent screening methods. In order to appeal to new donors it is important to promote blood donations considering the profile of the regular and healthy blood donor of the existing population.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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Silver nanoparticles (AgNPs) are metal structures at the nanoscale. AgNPs have exhibited antimicrobial activities against fungi and bacteria; however synthesis of AgNPs can generate toxic waste during the reaction process. Accordingly, new routes using non-toxic compounds have been researched. The proposal of the present study was to synthesize AgNPs using ribose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. The antifungal activity of these particles against C. albicans and C. tropicalis was also evaluated. Stable nanoparticles 12.5 ± 4.9 nm (mean ± SD) in size were obtained, which showed high activity against Candida spp. and could represent an alternative for fungal infection treatment.

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Background: Allergic rhinitis and asthma (ARA) are chronic inflammatory diseases of the airways that often coexist in children. The only tool to assess the ARA control, the Control of Allergic Rhinitis and Asthma Test (CARAT) is to be used by adults. We aimed to develop the Pediatric version of Control of Allergic Rhinitis and Asthma Test (CARATkids) and to test its comprehensibility in children with 4 to 12 years of age. Methods: The questionnaire development included a literature review of pediatric questionnaires on asthma and/or rhinitis control and two consensus meetings of a multidisciplinary group. Cognitive testing was carried out in a cross-sectional qualitative study using cognitive interviews. Results: Four questionnaires to assess asthma and none to assess rhinitis control in children were identified. The multidisciplinary group produced a questionnaire version for children with 17 questions with illustrations and dichotomous (yes/no) response format. The version for caregivers had 4-points and dichotomous scales. Twenty-nine children, 4 to 12 years old, and their caregivers were interviewed. Only children over 6 years old could adequately answer the questionnaire. A few words/expressions were not fully understood by children of 6 to 8 years old. The drawings illustrating the questions were considered helpful by children and caregivers. Caregivers considered the questionnaire complete and clear and preferred dichotomous over the 4-points scales. The proportion of agreement between children and their caregivers was 61%. The words/expressions that were difficult to understand were amended. Conclusion: CARATkids, the first questionnaire to assess a child’s asthma and rhinitis control was developed and its content validity was assured. Cognitive testing showed that CARATKids is well-understood by children 6 to 12 years old. The questionnaire’s measurement properties can now be assessed in a validation study.

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SUMMARY The aim of this study was to evaluate the effects of the protein-calorie malnutrition in BALB/c isogenic mice infected with Lacazia loboi, employing nutritional and histopathological parameters. Four groups were composed: G1: inoculated with restricted diet, G2: not inoculated with restricted diet, G3: inoculated with regular diet, G4: not inoculated with regular diet. Once malnutrition had been imposed, the animals were inoculated intradermally in the footpad and after four months, were sacrificed for the excision of the footpad, liver and spleen. The infection did not exert great influence on the body weight of the mice. The weight of the liver and spleen showed reduction in the undernourished groups when compared to the nourished groups. The macroscopic lesions, viability index and total number of fungi found in the footpads of the infected mice were increased in G3 when compared to G1. Regarding the histopathological analysis of the footpad, a global cellularity increase in the composition of the granuloma was observed in G3 when compared to G1, with large numbers of macrophages and multinucleated giant cells, discrete numbers of lymphocytes were present in G3 and an increase was observed in G1. The results suggest that there is considerable interaction between Jorge Lobo's disease and nutrition.

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Species of the genus Leishmania (Kinetoplastida, Trypanosomatidae) are causative agents of leishmaniasis, a complex disease with variable clinical spectrum and epidemiological diversity, constituting, in some countries, a serious public health problem. The origin and evolution of leishmaniasis has been under discussion regarding some clinical and parasitological aspects. After the introduction of paleoparasitology, molecular methods and immunodiagnostic techniques have been applied allowing the recovery of parasite remains, as well as the diagnosis of past infections in humans and other hosts. The dating of archaeological samples has allowed the parasitological analysis in time and space. This manuscript presents the state of the art of leishmaniasis and prospects related to paleoparasitology studies and their contribution to the evolutionary and phylogenetic clarification of parasites belonging to the genus Leishmania, and the leishmaniasis caused by them.