970 resultados para Low voltage


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The aim of the present study was to investigate variations in oxidized LDL (oxLDL) at the onset of acute myocardial infarction (AMI) and over the recovery period, exploring their relationship with coronary disease severity. A follow-up of 50 AMI patients was evaluated against 25 healthy volunteers (reference group). The AMI patients were evaluated at three time points: at admission before the administration of IIb/IIIa inhibitors and angioplasty, and two and 40 days after intervention. Plasma oxLDL concentrations were measured by ELISA. oxLDL was found to be significantly higher in AMI patients in the acute phase relative to reference levels, decreasing progressively over the recovery period. The results also demonstrated that oxLDL levels were decreased in patients with the left circumflex artery (LCX) as culprit vessel compared to the left anterior descending coronary (LAD) or right coronary artery (RCA). The results highlight a significant increase in oxLDL concentration related to coronary artery disease severity, as conditions such as LCX lesions are usually associated with a favorable prognosis, contrasting with LAD-associated conditions that can compromise large areas of myocardium. The results thus suggest that oxLDL may constitute a promising marker in assessment of AMI evolution.

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This work presents a low cost RTK-GPS system for localization of unmanned surface vehicles. The system is based on the use of standard low cost L1 band receivers and in the RTKlib open source software library. Mission scenarios with multiple robotic vehicles are addressed as the ones envisioned in the ICARUS search and rescue case where the possibility of having a moving RTK base on a large USV and multiple smaller vehicles acting as rovers in a local communication network allows for local relative localization with high quality. The approach is validated in operational conditions with results presented for moving base scenario. The system was implemented in the SWIFT USV with the ROAZ autonomous surface vehicle acting as a moving base. This setup allows for the performing of a missions in a wider range of environments and applications such as precise 3D environment modeling in contained areas and multiple robot operations.

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Toxoplasmosis is one of the most common zoonoses worldwide. The seroprevalence for T. gondii in human population from Brazil might range from 40 to 80%. The aim of this paper was to study the seroprevalence of T. gondii infection in children from age one to 15 living in a low socioeconomic community, named community of Jardim São Remo in the year of 2002. The community is located in the West area of São Paulo municipality, São Paulo State, Brazil. Antibodies to T. gondii were found in 110 (32.4%, CI 95%: 27.5 - 37.7) of the 339 children tested with indirect immunofluorescent antibody test. The titration of the samples revealed 29 children with serum titer equal to 16, 14 children with 32, 18 children with 64, 21 children with 128, 20 children with 256 and eight children with serum titer > 512. The age dependence of the prevalence of T. gondii infection and the association between seroprevalence for T. gondii and seroprevalence for T. canis suggest that the infection is chiefly postnatal. Seroconversion in infant population of community Jardim São Remo occurs in children as young as two years old, earlier than in the children attended at health centers of São Paulo city. The seroprevalence of T. gondii in children from Jardim São Remo was compared to the prevalence in children from other urban centers of Brazil.

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In this study, energy production for autonomous underwater vehicles is investigated. This project is part of a bigger project called TURTLE. The autonomous vehicles perform oceanic researches at seabed for which they are intended to be kept operational underwater for several months. In order to ful l a long-term underwater condition, powerful batteries are combined with \micro- scale" energy production on the spot. This work tends to develop a system that generates power up to a maximum of 30 W. Latter energy harvesting structure consists basically of a turbine combined with a generator and low-power electronics to adjust the achieved voltage to a required battery charger voltage. Every component is examined separately hence an optimum can be de ned for all, and subsequently also an overall optimum. Di erent design parameters as e.g. number of blades, solidity ratio and cross-section area are compared for di erent turbines, in order to see what is the most feasible type. Further, a generator is chosen by studying how ux distributions might be adjusted to low velocities, and how cogging torque can be excluded by adapted designs. Low-power electronics are con gured in order to convert and stabilize heavily varying three-phase voltages to a constant, recti ed voltage which is usable for battery storage. Clearly, di erent component parameters as maximum power and torque are matched here to increase the overall power generation. Furthermore an overall maximum power is set up for achieving a maximum power ow at load side. Due to among others typical low velocities of about 0.1 to 0.5 m/s, and constructing limits of the prototype, the vast range of components is restricted to only a few that could be used. Hence, a helical turbine is combined in a direct drive mode to a coreless-stator axial- ux permanent-magnet generator, from which the output voltage is adjusted subsequently by a recti er, impedance matching unit, upconverter circuit and an overall control unit to regulate di erent component parameters. All these electronics are combined in a closed-loop design to involve positive feedback signals. Furthermore a theoretical con guration for the TURTLE vehicle is described in this work and a solution is proposed that might be implemented, for which several design tests are performable in a future study.

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An open trial to evaluate the azithromycin efficacy in cutaneous leishmaniasis patients was carried out in Manaus (AM), where Leishmania (Viannia) guyanensis is the main etiologic agent. Forty-one patients with skin lesions of less than 12 weeks duration, without specific treatment for the last three months and a positive imprint to Leishmania sp. were included. From these, 31 (75.6%) were male with median age of 30.2. All of them received a daily-single oral dose of 500 mg of azithromycin for ten days. At 25th day, 16 (39%) presented therapeutic failure and received intramuscular pentavalent antimonial, four were considered lost, 21, that had improved or were inaltered received another ten-day series of azithromycin and were monthly followed, but nine (21.9%) of them presented a poor clinical response and switched to intramuscular pentavalent antimonial on day 55. Of the 12 remaining cases evaluated on day 55, despite of clinical improvement, three asked for antimony therapy and 9 (21.9%) continued the follow-up but, only three were cured on 55th, 85th and 115th days, and six did not come back for final evaluation. The intention-treatment overall response rate was 22% and whole cure was seen in three (7.3%) of cases. Thus, azithromycin showed a low efficacy to treat cutaneous leishmaniasis in Manaus.

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This study was undertaken in the municipality of Bananal, São Paulo, an endemic area for schistosomiasis with a prevalence under 10% and low parasite load among infected individuals. Our objective was to identify the clinical forms of schistosomiasis among 109 patients in whom the disease had been diagnosed through direct fecal analysis and who had been medicated with oxamniquine at the time of the Plan for the Intensification of Schistosomiasis Control Actions (1998-2000). These patients were submitted to an abdominal ultrasonography and fecal analysis by Kato-Katz method, four years, on average, after the end of the Plan. Five patients, whose abdominal ultrasound images were compatible with either peripheral or central periportal fibrosis and portal hypertension, were identified. None of the 109 patients presented Schistosoma mansoni eggs at fecal analysis. Ultrasonography is a sensitive, noninvasive diagnostic method that allows a better identification of the extent of liver involvement in schistosomiasis cases.

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The Internet of Things (IoT) has emerged as a paradigm over the last few years as a result of the tight integration of the computing and the physical world. The requirement of remote sensing makes low-power wireless sensor networks one of the key enabling technologies of IoT. These networks encompass several challenges, especially in communication and networking, due to their inherent constraints of low-power features, deployment in harsh and lossy environments, and limited computing and storage resources. The IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) [1] was proposed by the IETF ROLL (Routing Over Low-power Lossy links) working group and is currently adopted as an IETF standard in the RFC 6550 since March 2012. Although RPL greatly satisfied the requirements of low-power and lossy sensor networks, several issues remain open for improvement and specification, in particular with respect to Quality of Service (QoS) guarantees and support for mobility. In this paper, we focus mainly on the RPL routing protocol. We propose some enhancements to the standard specification in order to provide QoS guarantees for static as well as mobile LLNs. For this purpose, we propose OF-FL (Objective Function based on Fuzzy Logic), a new objective function that overcomes the limitations of the standardized objective functions that were designed for RPL by considering important link and node metrics, namely end-to-end delay, number of hops, ETX (Expected transmission count) and LQL (Link Quality Level). In addition, we present the design of Co-RPL, an extension to RPL based on the corona mechanism that supports mobility in order to overcome the problem of slow reactivity to frequent topology changes and thus providing a better quality of service mainly in dynamic networks application. Performance evaluation results show that both OF-FL and Co-RPL allow a great improvement when compared to the standard specification, mainly in terms of packet loss ratio and average network latency. 2015 Elsevier B.V. Al

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Objective: to discuss the current PAHO recommendation that does not support the substitution of traditional cellular DTP vaccine by acellular DTP, and the role of mutations, in humans, as the main cause of rare adverse events, such as epileptic-like convulsions, triggered by pertussis vaccine. Data review: the main components related to toxic effects of cellular pertussis vaccines are the lipopolysaccharide of bacterial cell wall and pertussis toxin. The removal of part of lipopolysaccharide layer has allowed the creation of a safer cellular pertussis vaccine, with costs comparable to the traditional cellular vaccine, and which may be a substitute for the acellular vaccine. Conclusion: The new methodology introduced by Instituto Butantan allows for the development of a new safer pertussis vaccine with low LPS content (Plow), and the use of the lipopolysaccharide obtained in the process in the production of monophosphoryl lipid A. This component has shown potent adjuvant effect when administered together with influenza inactivated vaccine, making possible to reduce the antigen dose, enhancing the production capacity and lowering costs.

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Schistosomiasis constitutes a major public health problem, with an estimated 200 million individuals infected worldwide and 700 million people living in risk areas. In Brazil there are areas of high, medium and low endemicity. Studies have shown that in endemic areas with a low prevalence of Schistosoma infection the sensitivity of parasitological methods is clearly reduced. Consequently diagnosis is often impeded due to the presence of false-negative results. The aim of this study is to present the PCR reamplification (Re-PCR) protocol for the detection of Schistosoma mansoni in samples with low parasite load (with less than 100 eggs per gram (epg) of feces). Three methods were used for the lysis of the envelopes of the S. mansoni eggs and two techniques of DNA extraction were carried out. Extracted DNA was quantified, and the results suggested that the extraction technique, which mixed glass beads with a guanidine isothiocyanate/phenol/chloroform (GT) solution, produced good results. PCR reamplification was conducted and detection sensitivity was found to be five eggs per 500 mg of artificially marked feces. The results achieved using these methods suggest that they are potentially viable for the detection of Schistosoma infection with low parasite load.

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Culex quinquefasciatus is a vector of human pathogens, including filarial nematodes and several viruses. Although its epidemiological relevance is known to vary across geographical regions, an understanding of its population genetic structure is still incipient. In light of this, we evaluated the genetic diversity of Cx. quinquefasciatus and Cx. pipiens x Cx. quinquefasciatus hybrids collected from nine localities in Brazil and one site in Argentina. We used mitochondrial genes cox1 and nd4, along with the coxA and wsp genes of the maternally-inherited Wolbachia endosymbiont. The nd4 fragment was invariant between samples, whilst cox1 exhibited four haplotypes that separated two types of Cx. quinquefasciatus, one clustered in southern Brazil. Low sequence diversity was generally observed, being discussed. Both Brazilian and Argentinian mosquitoes were infected with a single Wolbachia strain. As reported in previous studies with these populations, cox1 and nd4 diversity is not congruent with the population structure revealed by nuclear markers or alar morphology. Future Cx. quinquefasciatus research should, if possible, evaluate mtDNA diversity in light of other markers.

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Dissertation presented to obtain the PhD degree in Electrical and Computer Engineering - Electronics

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Discoid lupus erythematosus (DLE) is a chronic, indolent, disfiguring disease that is characterized by scaly, erythematous, disk-shaped patches and plaques followed by atrophy, scarring and depigmentation. In a small number of patients, it is refractory to standard therapies. In several studies, thalidomide has been reported to be an effective treatment in those cases. The most fearful side effects are teratogenicity and neuropathy. Adequate counseling and vigilance must be given to the patients. We report a 45-year-old Portuguese woman who presented with a 20-year history of severe facial and scalp DLE confirmed by histopathology. For several years, it failed to respond to several therapies, including topical, intralesional and oral corticosteroids, hydroxychloroquine, methotrexate, azathioprine and topical tacrolimus. Thalidomide was initiated at a dosage of 50mg/day and the skin lesions had improved dramatically after three weeks with complete clinical remission. Two months later, the dose was reduced to 50mg, five days per week without disease rebound. The patient´s concomitant medications during the treatment included sunscreen, hydroxycholoroquine, enoxaparin and aspirin to prevent thromboembolic events. Pregnancy testing, routine laboratory and electrocardiography were performed at regular intervals for safety monitoring and the results were within normal limits. Only minor side effects as nausea, constipation and somnolence were noted, however, they improved with dose reduction. Our data confirm that thalidomide therapy is an alternative or adjunctive treatment for patients with severe, chronic DLE that is refractory to standard therapies. In this patient, low-dose thalidomide was an effective treatment with minimal side effects.

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A pre-Columbian Peruvian scalp was examined decades ago by a researcher from the Oswaldo Cruz Foundation. Professor Olympio da Fonseca Filho described nits and adult lice attached to hair shafts and commented about the origin of head lice infestations on mankind. This same scalp was sent to our laboratory and is the subject of the present paper. Analysis showed a massive infestation with nine eggs/cm2 and an impressive number of very well preserved adult lice. The infestation age was roughly estimated as nine months before death based on the distance of nits from the hair root and the medium rate of hair growth. A small traditional textile was associated with the scalp, possibly part of the funerary belongings. Other morphological aspects visualized by low-vacuum scanning electron microscopy are also presented here for adults and nits.

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Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores

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