Projecto e concepção de um dispositivo experimental para medição e caracterização dos esforços aplicados no finca-pés de um caiaque de pista: Investigação, desenho e desenvolvimento

Após o enquadramento da canoagem, como modalidade Olímpica, verificou-se um aumento significativo de estudos e pesquisas acerca da biomecânica da modalidade, o que contribuiu para uma diminuição dos tempos na competição. Contudo poucos foram os que se focaram nas forças desenvolvidas e aplicadas ao caiaque através do finca-pés, criado assim oportunidade de desenvolvimento de dispositivos para a medição das mesmas. Assim, o objectivo primordial é desenvolver um sistema experimental capaz de quantificar as forças geradas em cada um dos lados do finca-pés (esquerdo e direito). Este, deverá não só ser passível de se utilizar em caiaque ergómetro como também num caiaque de pista, permitido avaliar as forças aplicadas durante o ciclo de pagaiada, tanto em compressão como em tracção. A sua concepção baseou-se num modelo de finca-pés já existente, tornando-o compatível com os caiaques de competição mais comercializados, e permitindo que no futuro se possa utilizar na água, bastando para isso apenas possuir um caiaque e embarcar o sistema de medição. Este sistema experimental foi testado em caiaque ergómetro por 7 (sete) sujeitos com níveis distintos: seis homens (um atleta olímpico medalhado e cinco de nível nacional) e uma mulher (de nível de selecção Portuguesa) que, entre outros, realizaram um plano definido por 60s a uma frequência de 75 pagaiadas por minuto, seguido de uma intensa mudança de ritmo e força (Sprint). Após análise dos dados obtidos em cada um dos diferentes sujeitos, conseguimos identificar algumas das suas características, tais como: esforço assimétrico dos membros inferiores; utilização de forma heterogénea da fita do finca-pés; diferença de forças máximas aplicadas entre atletas (Ex.: para um atleta olímpico as forças medidas (Min; Max): Pé Esquerdo (- 444; 1087) N e Pé Direito (- 476; 1068) N); etc. Os resultados não só são bastante promissores como também são motivantes e congruentes com estudos anteriores, nomeadamente Begon et al. 2008 e Sturm 2010 e 2012. Finalmente, consegue-se afirmar, com segurança, que foram alcançados os objectivos propostos com a concepção deste dispositivo de medição de forças. Este permite caracterizar os esforços desenvolvidos no finca-pés por cada membro inferior, com ou sem a fita de suporte, possibilitando aos treinadores e atletas uma visão, para muitos desconhecida, das forças transmitidas e das suas assimetrias. No final, este conhecimento permitirá aos atletas melhorar o seu desempenho desportivo bem como facilitar a gestão desportiva, com base nos principais princípios mecânicos inerentes ao movimento dos atletas desde desporto Olímpico.

Análise de desempenho de algoritmos de otimização para extração de parâmetros em modelos semicondutores de potência

Apresenta-se nesta tese uma revisão da literatura sobre a modelação de semicondutores de potência baseada na física e posterior análise de desempenho de dois métodos estocásticos, Particle Swarm Optimizaton (PSO) e Simulated Annealing (SA), quando utilizado para identificação eficiente de parâmetros de modelos de dispositivos semicondutores de potência, baseado na física. O conhecimento dos valores destes parâmetros, para cada dispositivo, é fundamental para uma simulação precisa do comportamento dinâmico do semicondutor. Os parâmetros são extraídos passo-a-passo durante simulação transiente e desempenham um papel relevante. Uma outra abordagem interessante nesta tese relaciona-se com o facto de que nos últimos anos, os métodos de modelação para dispositivos de potência têm emergido, com alta precisão e baixo tempo de execução baseado na Equação de Difusão Ambipolar (EDA) para díodos de potência e implementação no MATLAB numa estratégia de optimização formal. A equação da EDA é resolvida numericamente sob várias condições de injeções e o modelo é desenvolvido e implementado como um subcircuito no simulador IsSpice. Larguras de camada de depleção, área total do dispositivo, nível de dopagem, entre outras, são alguns dos parâmetros extraídos do modelo. Extração de parâmetros é uma parte importante de desenvolvimento de modelo. O objectivo de extração de parâmetros e otimização é determinar tais valores de parâmetros de modelo de dispositivo que minimiza as diferenças entre um conjunto de características medidas e resultados obtidos pela simulação de modelo de dispositivo. Este processo de minimização é frequentemente chamado de ajuste de características de modelos para dados de medição. O algoritmo implementado, PSO é uma técnica de heurística de otimização promissora, eficiente e recentemente proposta por Kennedy e Eberhart, baseado no comportamento social. As técnicas propostas são encontradas para serem robustas e capazes de alcançar uma solução que é caracterizada para ser precisa e global. Comparada com algoritmo SA já realizada, o desempenho da técnica proposta tem sido testado utilizando dados experimentais para extrair parâmetros de dispositivos reais das características I-V medidas. Para validar o modelo, comparação entre resultados de modelo desenvolvido com um outro modelo já desenvolvido são apresentados.

Biological and genetic characteristics of uropathogenic Escherichia coli strains

The aim of the present study was to determine biological characteristics such as expression of fimbriae, Congo red binding, production of hemolysin and aerobactin, adhesion to HeLa and uroepithelial cells and invasion of HeLa cells by Escherichia coli isolates obtained from patients showing clinical signs of urinary tract infection (UTI). Also, the presence of genes (apa, afa, spa) for fimbria expression and cytotoxic necrotizing factors (CNF1, CNF2) was assayed using specific primers in PCR. The data obtained were compared with the clonal relationships obtained by analysis of multilocus enzyme electrophoresis (MLEE), restriction fragment length polymorphism (RFLP) of the rDNA (ribotyping) and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). All isolates but one presented a combination of at least two of the characteristics studied, a fact suggesting the presence of pathogenicity islands (PAIs). Diffuse adherence type to HeLa cells was observed to occur in most of the strains, but adhesion to uroepithelial cells seems to be a more reliable test to verify pathogenicity. Although four strains seemed to be able to invade HeLa cells when assayed by light microscopy, electron microscopy studies demonstrated that these strains were not invasive. MLEE, RFLP and ERIC-PCR were able to group the isolates differently into main clusters that were not correlated with the presence of pathogenic traits.

Electrospun Polyaniline-Reduced Graphene Oxide Composite Nanofibers Based High Sensitive Ammonia Gas Sensor

Ammonia is an important gas in many power plants and industrial processes so its detection is of extreme importance in environmental monitoring and process control due to its high toxicity. Ammonia’s threshold limit is 25 ppm and the exposure time limit is 8 h, however exposure to 35 ppm is only secure for 10 min. In this work a brief introduction to ammonia aspects are presented, like its physical and chemical properties, the dangers in its manipulation, its ways of production and its sources. The application areas in which ammonia gas detection is important and needed are also referred: environmental gas analysis (e.g. intense farming), automotive-, chemical- and medical industries. In order to monitor ammonia gas in these different areas there are some requirements that must be attended. These requirements determine the choice of sensor and, therefore, several types of sensors with different characteristics were developed, like metal oxides, surface acoustic wave-, catalytic-, and optical sensors, indirect gas analyzers, and conducting polymers. All the sensors types are described, but more attention will be given to polyaniline (PANI), particularly to its characteristics, syntheses, chemical doping processes, deposition methods, transduction modes, and its adhesion to inorganic materials. Besides this, short descriptions of PANI nanostructures, the use of electrospinning in the formation of nanofibers/microfibers, and graphene and its characteristics are included. The created sensor is an instrument that tries to achieve a goal of the medical community in the control of the breath’s ammonia levels being an easy and non-invasive method for diagnostic of kidney malfunction and/or gastric ulcers. For that the device should be capable to detect different levels of ammonia gas concentrations. So, in the present work an ammonia gas sensor was developed using a conductive polymer composite which was immobilized on a carbon transducer surface. The experiments were targeted to ammonia measurements at ppb level. Ammonia gas measurements were carried out in the concentration range from 1 ppb to 500 ppb. A commercial substrate was used; screen-printed carbon electrodes. After adequate surface pre-treatment of the substrate, its electrodes were covered by a nanofibrous polymeric composite. The conducting polyaniline doped with sulfuric acid (H2SO4) was blended with reduced graphene oxide (RGO) obtained by wet chemical synthesis. This composite formed the basis for the formation of nanofibers by electrospinning. Nanofibers will increase the sensitivity of the sensing material. The electrospun PANI-RGO fibers were placed on the substrate and then dried at ambient temperature. Amperometric measurements were performed at different ammonia gas concentrations (1 to 500 ppb). The I-V characteristics were registered and some interfering gases were studied (NO2, ethanol, and acetone). The gas samples were prepared in a custom setup and were diluted with dry nitrogen gas. Electrospun nanofibers of PANI-RGO composite demonstrated an enhancement in NH3 gas detection when comparing with only electrospun PANI nanofibers. Was visible higher range of resistance at concentrations from 1 to 500 ppb. It was also observed that the sensor had stable, reproducible and recoverable properties. Moreover, it had better response and recovery times. The new sensing material of the developed sensor demonstrated to be a good candidate for ammonia gas determination.

Intra-Task Device Scheduling for Real-Time Embedded Systems

An ever increasing need for extra functionality in a single embedded system demands for extra Input/Output (I/O) devices, which are usually connected externally and are expensive in terms of energy consumption. To reduce their energy consumption, these devices are equipped with power saving mechanisms. While I/O device scheduling for real-time (RT) systems with such power saving features has been studied in the past, the use of energy resources by these scheduling algorithms may be improved. Technology enhancements in the semiconductor industry have allowed the hardware vendors to reduce the device transition and energy overheads. The decrease in overhead of sleep transitions has opened new opportunities to further reduce the device energy consumption. In this research effort, we propose an intra-task device scheduling algorithm for real-time systems that wakes up a device on demand and reduces its active time while ensuring system schedulability. This intra-task device scheduling algorithm is extended for devices with multiple sleep states to further minimise the overall device energy consumption of the system. The proposed algorithms have less complexity when compared to the conservative inter-task device scheduling algorithms. The system model used relaxes some of the assumptions commonly made in the state-of-the-art that restrict their practical relevance. Apart from the aforementioned advantages, the proposed algorithms are shown to demonstrate the substantial energy savings.

Novel biosensing device for point-of-care applications with plastic antibodies grown on Au-Screen Printed Electrodes

A gold screen printed electrode (Au-SPE) was modified by merging Molecular Imprinting and Self-Assembly Monolayer techniques for fast screening cardiac biomarkers in point-of-care (POC). For this purpose, Myoglobin (Myo) was selected as target analyte and its plastic antibody imprinted over a glutaraldehyde (Glu)/cysteamine (Cys) layer on the gold-surface. The imprinting effect was produced by growing a reticulated polymer of acrylamide (AAM) and N,N′-methylenebisacrylamide (NNMBA) around the Myo template, covalently attached to the biosensing surface. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) studies were carried out in all chemical modification steps to confirm the surface changes in the Au-SPE. The analytical features of the resulting biosensor were studied by different electrochemical techniques, including EIS, square wave voltammetry (SWV) and potentiometry. The limits of detection ranged from 0.13 to 8 μg/mL. Only potentiometry assays showed limits of detection including the cut-off Myo levels. Quantitative information was also produced for Myo concentrations ≥0.2 μg/mL. The linear response of the biosensing device showed an anionic slope of ~70 mV per decade molar concentration up to 0.3 μg/mL. The interference of coexisting species was tested and good selectivity was observed. The biosensor was successfully applied to biological fluids.

Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: Application to sulfamethoxazole and trimethoprim

Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices to carry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/μPOT) was developed for the first time for an organic compound: sulfamethoxazole (SMX). Sensory materials relied on newly designed plastic antibodies. Sol–gel, self-assembling monolayer and molecular-imprinting techniques were merged for this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conducted around SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were used as ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysis was verified in flow-injection studies with regular tubular electrodes. The LTCC/μPOT device integrated a bidimensional mixer, an embedded reference electrode based on Ag/AgCl and an Ag-based contact screen-printed under a micromachined cavity of 600 μm depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Under optimum conditions, the SMX sensor displayed slopes of about −58.7 mV/decade in a range from 12.7 to 250 μg/mL, providing a detection limit of 3.85 μg/mL and a sampling throughput of 36 samples/h with a reagent consumption of 3.3 mL per sample. The system was adjusted later to multiple analyte detection by including a second potentiometric cell on the LTCC/μPOT device. No additional reference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, and tested in fish-farming waters. The biparametric microanalyzer displayed Nernstian behaviour, with average slopes −54.7 (SMX) and +57.8 (TMP) mV/decade. To demonstrate the microanalyzer capabilities for real applications, it was successfully applied to single and simultaneous determination of SMX and TMP in aquaculture waters.

Effects of molybdate and tungstate on expression levels and biochemical characteristics of formate dehydrogenases produced by desulfovibrio alaskensis NCIMB 13491

Journal of Bacteriology. 2011 Jun; Vol. 193 issue 12 pages 2917-2923

A Triatoma maculata (Hemiptera, Reduviidae, Triatominae) population from Roraima, Amazon region, Brazil, has some bionomic characteristics of a potential Chagas disease vector

Even though Chagas disease is rare in the Brazilian Amazon, the conditions for the establishment of domiciliated cycles prevail in many areas where triatomines are of frequent occurrence. In Roraima, a previous serological and entomological survey in three agricultural settlements showed the existence of all transmission cycle elements, i.e., individuals infected by Trypanosoma cruzi, triatomine species previously found harboring T. cruzi in the broader Amazon region of neighboring countries and, domicile/ peridomicile conditions favorable to triatomine colonization. Triatoma maculata was the most frequent species, found in chicken houses in the peridomicile and sporadically within residences. Aiming to investigate the possibility of T. maculata to possess the potentiality to transmit T. cruzi in the area, bionomic characteristics were studied under laboratory conditions. These were feeding frequency, time for defecation after a blood meal, time elapsed in voluntary fasting pre- and pos-ecdysis, moulting time periods, pre-oviposition and oviposition periods and index of oviposition, incubation period, egg viability, longevity and mortality rate. Results show that the Passarão population of T. maculata should be considered a potential vector of T. cruzi since it shows a capacity to infest artificial ecotopes in the peridomicile, to carry out large number of meals during the nymphal cycle, to have a relatively short developmental cycle capable of producing 2.9 generations/year, to blood source eclecticism, to defecate immediately after the blood meal while still on the host and to the fact that has been previously found naturally infected by T.cruzi.

Clinical characteristics and evolution of syphilis in 24 HIV+ individuals in Rio de Janeiro, Brazil

A total of 24 patients with syphilis and HIV infection were treated from January 1997 to March 2003 at the Infectious Dermatology Outpatient Clinic of the Evandro Chagas Clinical Research Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil. The caseload consisted of 20 males (83.3%) and four females (16.7%), with a mean age of 38.04 years and mean T CD4+ count of 389.5 cells/mL. Syphilis was diagnosed as secondary in 16 (62.5%) patients, late latent in eight (33.3%), and tertiary in one (4.2%). Manifestations of secondary syphilis were palmar and plantar erythematopapulous cutaneous lesions in nine (37.5%), papulous exanthema in four (16.7%), patchy alopecia in 3 (12.5%) and osteochondritis in one patient (4.2%). Tertiary syphilis was characterized by verrucous lesions. Neurosyphilis was diagnosed in four patients (16.7%), with headache as the only manifestation in two patients. Drugs used in treatment included benzathine penicillin, ceftriaxone, erythromycin, and crystalline penicillin. Cure was achieved in 18 patients (75%). Five patients (20.8%) were retreated, three of whom presented a history of re-exposure. This study confirms the importance of establishing the diagnosis of neurosyphilis in patients with HIV infection, in addition to performing follow-up on treatment for syphilis.

Socio-demographic and epidemiological characteristics associated with human immunodeficiency virus type I (HIV-1) infection in HIV-1-explosed but uninfected individuals, and in HIV-1-infected patients from a southern brasilian population

The ability to control human immunodeficiency virus type 1 (HIV-1) infection and progression of the disease is regulated by host and viral factors. This cross-sectional study describes the socio-demographic and epidemiological characteristics associated with HIV-1 infection in 1,061 subjects attended in Londrina and region, south of Brazil: 136 healthy individuals (Group 1), 147 HIV-1-exposed but uninfected individuals (Group 2), 161 HIV-1-infected asymptomatic patients (Group 3), and 617 patients with AIDS (Group 4). Data were obtained by a standardized questionnaire and serological tests. The age of the individuals ranged from 15.1 to 79.5 years, 54.0% and 56.1% of the Groups 3 and 4 patients, respectively, were men. The major features of groups 2, 3, and 4 were a predominance of education level up to secondary school (55.8%, 60.2% and 62.4%, respectively), sexual route of exposure (88.4%, 87.0% and 82.0%, respectively), heterosexual behavior (91.8%, 75.2% and 83.7%, respectively), and previous sexually transmitted diseases (20.4%, 32.5%, and 38.1%, respectively). The patients with AIDS showed the highest rates of seropositivity for syphilis (25.6%), of anti-HCV (22.3%), and anti-HTLV I/II obtained by two serological screening tests (6.2% and 6.8%, respectively). The results documenting the predominant characteristics for HIV-1 infection among residents of Londrina and region, could be useful for the improvement of current HIV-1 prevention, monitoring and therapeutic programs targeted at this population.

Candiduria in a public hospital of São Paulo (1999-2004): characteristics of the yeast isolates

The study involved 100 yeast isolates, obtained from urine samples provided by a Public Pediatric Hospital of São Paulo, Brazil, from 1999 to 2004. The most frequent species was Candida albicans, followed by C. tropicalis, C. glabrata and C. parapsilosis. In regard to virulence, 97% of the isolates showed index 3 for proteinase and 63% index 2 for phospholipase. The most frequent killer biotypes were 511 and 888.

Clinical and histological characteristics of HIV and hepatitis C virus-co-infected patients in Brazil: a case series study

Hepatitis C virus (HCV) is an important factor contributing to morbidity and mortality in patients co-infected with HIV and HCV. In addition, liver biopsy is an important tool in the clinical management of these patients. Although liver biopsy is controversial, it is recommended for all patients. Data regarding the clinical and histological characteristics of these patients are scarce not only in Brazil but in Latin America as a whole. With the goal of better understanding these characteristics and the benefit of liver biopsy indications in this disease setting, data collected from 234 patients followed from 1996 to 2004 at Casa da AIDS, São Paulo, were analyzed. The following variables were extracted from the patients' medical files at the time of liver biopsy: sex, age, hepatitis C infection risk factors, hepatitis C infection duration, ALT levels, CD4+ T cell counts, history of alcohol abuse, history of antiretroviral therapy, HCV genotype, and liver histological alterations. CONCLUSIONS: 1 - Hepatitis C virus 1 and 3 were the most frequently identified genotypes and were diagnosed in 72% and 25.5% of cases respectively; 2 - Structural liver alterations were found to be mild or absent in 48.2% (113/234) of the analyzed patients; 3 - Fifty-three patients (23%) had normal ALT levels and 4 - Significant liver architectural changes (F2-F3) were evident in 22.5% of the patients with normal ALT levels.

A Study on Microstructure Characteristics of TEPs-modified Adhesives

Thermally expandable particles (TEPs) were developed by Dow Chemical Co in the early 1970´s [1] and were further developed by others [2, 3]. They are particles made up of a thermoplastic shell filled with liquid hydrocarbon. On heating them, two transformations will occur. One is the softening of shell material and the other is the gasification of the hydrocarbon liquid inside it. As a consequence, the shell will expand as the gas inside it will push the softened shell from inside out causing it to grow in size [4]. When fully expanded, the growth in volume of the particle can be from 50 to 100 times [3]. Owing to this unique behaviour, TEPs are used by the industry in a wide variety of applications mainly for weight reduction and appearance improvement for thermoplastics, inks, and coatings. In adhesive bonding, TEPs have been used for recycling purposes. Moreover, TEPs might be used to modify structural adhesives for other new purposes, such as: to increase the joint strength by creating an adhesive functionally modified along the overlap of the joint by gradual heating and/or to heal the adhesive in case of damage.

Epilepsy and Cerebral Palsy: Characteristics and Trends in Children Born in 1976 - 1998

Background: Although epilepsy is common in children with cerebral palsy (CP), no data exists on prevalence rates of CP and epilepsy. Aims: To describe epilepsy in children with CP, and to examine the association between epilepsy and neonatal characteristics, associated impairments and CP subtypes. Methods: Data on 9654 children with CP born between 1976 and 1998 and registered in 17 European registers belonging to the SCPE network (Surveillance of Cerebral Palsy in Europe)were analyzed. Results: A total of 3424 (35%) children had a history of epilepsy. Among them, seventy-two percent were on medication at time of registration. Epilepsy was more frequent in children with a dyskinetic or bilateral spastic type and with other associated impairments. The prevalence of CP with epilepsy was 0.69 (99% CI, 0.66e0.72) per 1000 live births and followed a quadratic trend with an increase from 1976 to 1983 and a decrease afterwards. Neonatal characteristics independently associated with epilepsy were the presence of a brain malformation or a syndrome, a term or moderately preterm birth compared with a very premature birth, and signs of perinatal distress including neonatal seizures, neonatal ventilation and admission to a neonatal care unit. Conclusions: The prevalence of CP with epilepsy followed a quadratic trend in 1976e1998 and mirrored that of the prevalence of CP during this period. The observed relationship between epilepsy and associated impairments was expected; however it requires longitudinal studies to be better understood.