Estudo e otimização de uma pilha de combustível de pequena potência (10W) e sua integração em equipamento portátil

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia MecânicaCom o presente trabalho pretende-se, em termos globais, contribuir para o aprofundamento do conhecimento sobre as pilhas de combustível a hidrogénio através do estudo de uma pilha de combustível de pequena potência (10W) e a sua integração em equipamento portátil. Em termos estruturais, de uma forma geral, esta dissertação engloba três partes distintas, uma parte inicial na qual se procede a uma revisão de literatura, uma segunda parte, na qual é efetuado um estudo acerca da implementação da pilha de combustível a hidrogénio no equipamento portátil escolhido, por fim, uma terceira parte na qual é apresentada uma simulação do funcionamento dessa pilha com a devida discussão sobre os resultados obtidos, bem como sobre as limitações do estudo. Foram delineados três objetivos para este trabalho: o estudo teórico das pilhas de combustível, composto pelo estudo do seu princípio de funcionamento, das suas características, do tipo de combustível, das aplicações e dos desafios existentes neste tipo de tecnologia; o estudo comparativo entre as pilhas de combustível e outras tecnologias no mercado; e a implementação de uma pilha a hidrogénio num equipamento portátil escolhido por mim e estudo das suas características em funcionamento. A implementação de uma pilha de combustível a hidrogénio num equipamento portátil foi conseguida através do recurso ao programa Matlab®. Assim, foi possível a simulação do funcionamento da pilha para o equipamento selecionado. A simulação permitiu analisar e compreender o processo no interior da pilha de hidrogénio e o que esta transmite para o equipamento portátil. Em termos de resultados, estes foram suficientes para se ajuizar sobre as curvas características típicas de uma pilha de hidrogénio, nomeadamente da variação da corrente e da tensão com a variação de carga aplicada na pilha de hidrogénio.Abstract: The intention with the present work, in global terms, is to contribute for a more profound understanding about the hydrogen fuel cells from the studies of a low power fuel cell (10W) and its integration on portable equipment. In structural terms, in a general way, this thesis is assembled in three distinct parts, one consisting in a literature revision, a second in a study about the implementation of a hydrogen fuel cell in a particularly chosen portable equipment, and a third consisting in a simulation and discussion of obtained results of a fuel cell operation as well as study shortfalls. There were three objectives to be considered for this work: the theoretical study of the fuel cell, consisting on the: (i) study of the operation principle, (ii) main features, (iii) fuel type, (iv) existing applications and (v) technology challenges; the study of its functioning characteristics and also the comparative study between fuel cells and other technologies available in the market and the implementation of a hydrogen fuel cell in a portable equipment chosen by me. The implementation of a hydrogen fuel cell in a portable equipment was only possible resorting to the Matlab® program. Therefore, it was possible to simulate in the selected equipment the functioning of the fuel cell. The simulation allowed the analysis and the understanding of the interior process of the hydrogen fuel cell and what it provides to the portable equipment. Concerning results, these were more than enough to get the typical outline of the characteristic curves of a hydrogen fuel cell, mostly about the current and tension variation with the charge variation applied the hydrogen fuel cell

Evaluation of experimental infection with Neospora caninum in bubaline and bovine females, in the first third of pregnancy

Neospora caninum é um protozoário parasita de grande importância em todo o mundo, sendo considerado a principal causa de abortamento bovino em algumas localidades. Enquanto a implicação deste parasita em distúrbios reprodutivos na espécie bovina seja conhecida, as informações disponíveis com a espécie bubalina são escassas. Este estudo avaliou e comparou as consequências da infecção experimental por N. caninum em búfalas e vacas, no estágio inicial da gestação, o de maior importância no que se refere à ocorrência de morte fetal. Protocolos de inseminação artificial em tempo fixo foram utilizados para maior controle da fecundação. Foram utilizados para inoculação dois isolados distintos, Nc-Bahia e Nc-1, possibilitando a comparação entre o isolado nacional e o isolado padrão. Todos os animais foram inoculados com 5 x 108 taquizoítos, pela via endovenosa, no 70º dia de gestação. Três búfalas e cinco vacas foram infectadas com o isolado Nc-Bahia, sendo detectado abortamento 42 dias pós-infecção (DPI) em somente uma das vacas inoculadas. Três búfalas e duas vacas foram inoculadas com o isolado Nc-1 e morte fetal foi detectada 35 DPI em todas as búfalas e vacas. Uma búfala e uma vaca permaneceram como controles negativos, sem infecção. A transmissão vertical foi verificada por semi-nested PCR nos animais infectados com Nc-Bahia e Nc-1. Diferentes graus de inflamação não-supurativa foram detectados em tecidos maternos, fetais e placentários. Todas as fêmeas inoculadas apresentaram resposta humoral frente à infecção. Embora a infecção estivesse mais disseminada pelo organismo das búfalas (p<0,05), a resposta humoral foi menor (p<0,05) e as lesões histológicas foram menos frequentes (p<0,05), indicando haver maior adaptação entre N. caninum e as búfalas, em comparação com os resultados obtidos nas vacas. O isolado Nc-Bahia foi menos patogênico que o Nc-1, por causar menos abortamentos (p<0,05) e menor frequência de lesões histológicas (p<0,05). A patogenicidade do agente na espécie bubalina foi confirmada, consideradas as lesões encontradas na análise histopatológica e a detecção da presença do agente por semi-nested PCR nos diversos tecidos estudados, além da positividade por imunoistoquímica em placenta e cérebro fetal bubalino. Esta é a primeira detecção de abortamento causado por N. caninum na espécie bubalina, em fêmeas infectadas experimentalmente com o protozoário, confirmando que problemas reprodutivos podem ser causados pelo N. caninum em búfalas.Neospora caninum is a protozoan parasite with big importance all over the world, being considered the main cause of bovine abortion in some locations. While the implication of this parasite in bovine reproductive disorders is known, the available information within the buffalo species is scarce. This study evaluated and compared the consequences of experimental infection with N. caninum in buffaloes and cows on the initial stage of pregnancy, the most important regarding to the occurrence of fetal death. Protocols for fixed-time artificial insemination were used for greater control of fertilization. Two different isolates, Nc-Bahia and Nc-1, were utilized for inoculation, allowing the comparison between the national isolate and the standard isolate. All animals were inoculated with 5 x 108 tachyzoites, by endovenous route, at the 70th day of pregnancy. Three buffaloes and five cows were infected with the isolate Nc-Bahia and abortion was detected 42 days post-infection (DPI) in only one inoculated cow. Three buffaloes and two cows were inoculated with the isolate Nc-1 and fetal death was detected 35 DPI in all buffaloes and cows. A buffalo and a cow remained as negative controls, without infection. Vertical transmission was verified by semi-nested PCR in animals infected with Nc-Bahia and Nc-1. Different degrees of nonsuppurative inflamation were detected in maternal, foetal and placental tissues. All inoculated females showed humoral response against the infection. Although the infection was more disseminated withn the body of buffaloes (p <0.05), the humoral response was lower (p <0.05) and histological lesions were less frequent (p <0.05), indicating bigger adaptation between N. caninum and the buffaloes, in comparison with the results obtained in cows. Nc-Bahia isolate was less pathogenic than the Nc- 1, as it caused less abortions (p <0.05) and lower frequency of histological lesions (p<0.05). The pathogenicity of the agent in the bubaline species was confirmed, considering the lesions found on histopathology analysis and the detection of the agent´s presence by semi-nested PCR in the different studied tissues, in addition to the positivity by immunohistochemistry test in bubaline placenta and foetal brain. This is the first detection of abortion caused by N. caninum in buffalo species, in females experimentally infected with the protozoan, confirming that reproductive disorders can be caused by N. caninum in buffaloes

Evidence of congenital transmission of Neospora caninum in naturally infected water buffalo (Bubalus bubalis) fetus from Brazil

The aim of this study was to determine the congenital infection by Neospora caninum in the water buffalo (Bubalus bubalis), a natural intermediate host. Nine pregnant water buffalos, raised under free-grazing condition, were slaughtered, and their fetuses were collected. Samples of brain and thoracic fluid were obtained from those fetuses, with gestational ages ranging from 2 to 5 months. The DNA of N. caninum was detected and identified in the brain of one of those fetuses, using two PCR assays, one directed to the Nc5 gene and the other, to the common toxoplasmatiid ITS1 sequence. The DNA fragments produced on PCR were sequenced, and N. caninum was confirmed in the samples. No antibodies to N. caninum were detected on any sample of thoracic fluid by immunofluorescent antibody test (IFAT < 25). This is the first confirmation of congenital transmission of N. caninum in water buffalos

Pathogenicity of Nc-Bahia and Nc-1 strains of Neospora caninum in experimentally infected cows and buffaloes in early pregnancy

Neospora caninum is a protozoan parasite known as an important cause of bovine abortion worldwide. Little is currently known about how different strains of N. caninum vary in their pathogenicity. In this study, we compared a Brazilian strain, Nc-Bahia, with the first isolate of this coccidian, Nc-1. Eight cows and seven buffaloes were submitted to fixed-time artificial insemination protocols for a better control of pregnancy. Group 1 was inoculated with Nc-Bahia (n = 8; five cows and three buffaloes), and Group 2 was inoculated with Nc-1 (n = 5; two cows and three buffaloes). One nonpregnant female of each species was left uninfected as sentinel controls for potential environmental infection. All inoculated animals received 5 × 108 tachyzoites of N. caninum, by intravenous route, on the 70th day of gestation. Uninfected animals remained seronegative throughout the experiment, indicating no exogenous infection, whereas all inoculated animals became seropositive to N. caninum. In Group 1, abortion was found in only one cow on 42 days postinfection (dpi; frequency of abortion = 12.5 %), whilst all animals from Group 2 aborted on 35 dpi (frequency of abortion = 100 %). Parasite DNA was detected by seminested PCR in maternal, foetal and placental tissues, confirming vertical transmission in Groups 1 and 2, although histological lesions had different frequencies and degrees of severity between the groups. There was evidence of lower pathogenicity of Nc-Bahia compared to Nc-1 when used in experimental infection, as it caused fewer abortions, as well as less frequent and milder histological lesions. This was the first time Nc-Bahia has been used for experimental infection.EEA BalcarceFil: Chryssafidis, Andreas Lazaros. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; Brasil. University College Dublin. UCD School of Veterinary Medicine, Veterinary Science Centre; IrlandaFil: Canton, German Jose. Moredun Research Institute; Reino Unido. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Chianini, Francesca. Moredun Research Institute; Reino UnidoFil: Innes, Elisabeth A. Moredun Research Institute; Reino UnidoFil: Madureira, Ed Hoffmann. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Reprodução Animal; BrasilFil: Gennari, Solange Maria. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; Brasi

Successful treatment of Trypanoxyuris sp. infection in naturally infected southern brown-howlers (Alouatta guariba clamitans)

Southern brown-howler monkeys (Alouatta guariba clamitans) may harbor Trypanoxyuris sp., a pinworm parasite with documented fatal consequences in this species. Despite this risk, effective treatment protocols remain unclear. Therefore, the present study aimed to evaluate the efficacy of two anthelmintic protocols against natural infections in two brown-howler monkeys received at the Wild Animal Care and Rehabilitation Sector (SARAS-CAV-UDESC). The protocols utilized pyrantel pamoate &amp; praziquantel (600.0 mg, PO, single dose) and albendazole (20.0 mg, PO, daily for 5 days). Fecal egg counts were carried out daily at the Laboratory of Parasitology and Parasitic Diseases (LAPAR-CAV-UDESC) before and after drug administration. Both treatments successfully eliminated Trypanoxyuris sp. infections. The animal treated with pyrantel pamoate &amp; praziquantel achieved egg clearance by day 6 (144 h), demonstrating effectiveness with a single administration. Albendazole cleared the infection within 2 days of treatment, indicating its potential as a fast-acting treatment. No adverse effect were observed in the treated monkeys. These findings contribute to the development of evidence-based treatment protocols for Trypanoxyuris sp. in primates, enhancing animal health and welfare of captive and wild populations

Fluopsin C: A Review of the Antimicrobial Activity against Phytopathogens

Fluopsin C (FlpC) is an organocupric secondary metabolite with low-molecular-weight, produced by some Pseudomonas and Streptomyces bacteria. The compound was identified in 1970 as prismatic dark-green crystals, with strong antimicrobial activity against several human and phytopathogens. Due to its high cytotoxicity, research on this compound decreased after the 1970s. During the early 2000s, FlpC gained more attention as a promising compound by which to develop new antimicrobials to control human, animal, and plant pathogens. This study provides an overview of the results pertaining to the in vitro and in vivo antimicrobial activity of pure FlpC, as well as semi-purified fractions containing FlpC, against phytopathogenic microorganisms. Furthermore, the bioprospection history of the extensively researched FlpC-producing Pseudomonas aeruginosa LV strain and the related molecular evidence regarding the compound’s biosynthesis are discussed. Overall, FlpC is proposed to be an important alternative to antimicrobial resistance in human and animal health, and in tackling the negative environmental impacts caused by the exacerbated use of pesticides against phytopathogens

Prevalence of Eimeria spp. in calves from dairy farms in northern Paraná state, Brazil

<div><p>Abstract Bovine coccidiosis is a disease of major importance in cattle herds across the world. The disorder mainly affects young calves, and E. bovis and E. zuernii are considered the most pathogenic species of the genus, however, E. alabamensis have been described in grazing calves. In this study, the prevalence of Eimeria spp. was evaluated in calves on dairy farms in the northern region of the state of Paraná, Brazil. Four hundred calves on 44 dairy farms were tested for the presence of coccidian oocysts. The positives were re-examined and the oocysts were morphometrically analyzed for species identification. All the farms were contaminated and 205 animals (51.25%) presented Eimeria spp. oocysts. Among these, 146 animals (71.22%) were co-infected by two or more species of coccidia. Ten species of Eimeria were identified: E. bovis (in 30.25% of the positive samples), E. alabamensis (26.75%), E. zuernii (22.00%), E. ellipsoidalis (18.50%), E. auburnensis (13.75%), E. canadensis (8.00%), E. cylindrica (7.25%), E. subspherica (5.00%), E. bukidnonensis (3.00%) and E. brasiliensis (0.75%). This study demonstrates the high prevalence of Eimeria spp. in the northern region of Paraná, Brazil, and detection for the first time in our region the pathogenic species E. alabamensis.</p></div

Fluopsin C for treating multidrug-resistant infections: In vitro activity aganist clinically important strains and in vivo efficacy against carbapenemase-producing Klebsiella pneumoniae

The increasing emergence of multidrug-resistant (MDR) organisms in hospital infectionsis causing a global public health crisis. The development of drugs with effective antibioticaction against such agents is of the highest priority. In the present study, the actionof Fluopsin C against MDR clinical isolates was evaluated underin vitroandin vivoconditions. Fluopsin C was produced in cell suspension culture ofPseudomonasaeruginosaLV strain, purified by liquid adsorption chromatography and identified bymass spectrometric analysis. Bioactivity, bacterial resistance development risk againstclinically important pathogenic strains and toxicity in mammalian cell were initiallydetermined byin vitromodels.In vivotoxicity was evaluated inTenebrio molitorlarvae and mice. The therapeutic efficacy of intravenous Fluopsin C administration wasevaluated in a murine model ofKlebsiella pneumoniae(KPC) acute sepsis, using sixdifferent treatments. Thein vitroresults indicated MIC and MBC below 2μg/mL and lowbacterial resistance development frequency. Electron microscopy showed that FluopsinC may have altered the exopolysaccharide matrix and caused disruption of the cell wallof MDR bacteria. Best therapeutic results were achieved in mice treated with a singledose of 2 mg/kg and in mice treated with two doses of 1 mg/kg, 8 h apart. Furthermore,acute and chronic histopathological studies demonstrated absent nephrotoxicity andmoderate hepatotoxicity. The results demonstrated the efficacy of Fluopsin C againstMDR organisms inin vitroandin vivomodels, and hence it can be a novel therapeuticagent for the control of severe MDR infection