Controlo inteligente de um Sistema de Levitação Magnética

A levitação magnética tem sido um tema bastante investigado sobretudo devido à sua utilização em sistemas ferroviários de transportes. É o método ideal quando existe a necessidade em aplicações de restringir do contacto físico, ou a conveniência, em termos energéticos, de eliminar o atrito. O princípio de funcionamento é simples, um eletroíman cria uma força sobre um objeto ferromagnético que contraria a gravidade. Contudo um sistema de levitação por atração é instável e não linear, o que significa a necessidade de implementar um controlador para satisfazer as características de estabilidade desejadas. Ao longo deste projeto serão descritos os procedimentos teóricos e práticos que foram tomados na criação de um sistema de levitação eletromagnética. Desde a conceção física do sistema, como escolha do sensor, condicionamento de sinal ou construção do eletroíman, até aos procedimentos matemáticos que permitiram a modelação do sistema e criação de controladores. Os controladores clássicos, como o PID ou em avanço de fase, foram projetados através da técnica do Lugar Geométrico de Raízes. No projeto do controlador difuso, pelo contrário não se fez uso da modelação do sistema ou de qualquer relação matemática entre as variáveis. A utilização desta técnica de controlo destacou-se pela usa simplicidade e rapidez de implementação, fornecendo um bom desempenho ao sistema. Na parte final do relatório os resultados obtidos pelos diferentes métodos de controlo são analisados e apresentadas as respetivas conclusões. Estes resultados revelam que para este sistema, relativamente aos outros métodos, o controlador difuso apresenta o melhor desempenho tanto ao nível da resposta transitória, como em regime permanente.

On the unknown ecological niche of Paracoccidioides brasiliensis: our hypothesis of 1989: present status and perspectives

In 1989, CONTI DÍAZ & RILLA published a hypothesis concerning the as yet unknown ecological niche of Paracoccidioides brasiliensis. The hypothesis proposed a highly efficient paracoccidioidal ecological strategy based on an important natural reservoir of the parasite, probably in heterothermic animals from fresh water environments. Further, the hypothesis proposed, a transient and variable residence in the soil with a wide aleuriospore dispersion throughout the environment together with an elevated capability of infecting humans, and domestic and wild animals. This paper analyzes scientific publications from the IX International Meeting on Paracoccidioidomycosis held in Águas de Lindoia, São Paulo, Brazil from 2-5 October 2005, providing a comparative study among this articles and with other recently published papers and the hypothesis' postulates. Since various findings and observations appear to agree with the postulates, the pursuit of novel, specific research projects in the supposed reservoirs is recommended partially or fully to confirm the hypothesis using classical laboratorial methods and modern molecular biology techniques.

Abdominal angiostrongyliasis: report of two cases with different clinical presentations

Abdominal angiostrongyliasis is a sporadic infectious disease caused by the nematode Angiostrongylus costaricensis. It usually presents as acute abdomen, secondary to mesenteric ischemia, and pronounced eosinophilia. In some cases its course is insidious and transient, and the diagnosis is suspicious. The disease is confirmed by the detection of A. costaricensis elements in surgical specimen. The treatment is supportive, with avoidance of antihelminthic administration due to a possible erratic migration followed by worsening of the disease. We report two cases, both with intense eosinophilia and serum IgG-ELISA positive to A. costaricensis. The first case presented ileal perforation and was surgically treated. The second one showed hepatic nodules at ultrasound and was only symptomatically treated, evolving to an apparent protracted resolution. These two cases exemplify different clinical forms of the disease, one of them with liver involvement.

Transoesophageal Echocardiography for Monitoring Liver Surgery: Data from a Pilot Study

A pilot study aimed to introduce intraoperative monitoring of liver surgery using transoesophageal echocardiography (TEE) is described. A set of TEE measurements was established as a protocol, consisting of left atrial (LA) dimension at the aortic valve plane; mitral velocity flow integral, calculation of stroke volume and cardiac output (CO); mitral annular plane systolic excursion; finally, right atrial area. A total of 165 measurements (on 21 patients) were performed, 31 occurring during hypotension. The conclusions reached were during acute blood loss LA dimension changed earlier than CVP, and, in one patient, a dynamic left ventricular (LV) obstruction was observed; in 3 patients a transient LV systolic dysfunction was documented. The comparison between 39 CO paired measurements obtained by TEE and PiCCO2 revealed a statistically significant correlation (P < 0.001, r = 0.83). In this pilot study TEE successfully answered the questions raised by the anesthesiologists. Larger cohort studies are needed to address this issue.

A historical note on an imported case of loiasis in Rio de Janeiro, Brazil, 1964

Loiasis is a filarial disease transmitted by the Chrysops spp. tabanid flies in West and Central Africa. It is most commonly diagnosed by the clinical manifestations of Calabar swellings (transient localized inflammatory edema) or, most dramatically, by the appearance of a migrating worm through the conjunctival tissues or the bridge of the nose. We report the case of a 35-year-old resident in the city of Rio de Janeiro who displayed a moving Loa loa in the bulbar conjunctival tissue two years after returning from a six-month trip to Uganda. Surgical removal of the worm was performed.

Intravenous Immunoglobulin for the Treatment of Quetiapin-Induced Bullous Pemphigoid in an HIV-Infected Patient

The authors present the case of a 48-year-old woman with HIV-­associated dementia treated with antiretroviral therapy and psychoactive drugs, to whom bullous pemphigoid(BP) was diagnosed. Given incomplete response to corticotherapy, and azathioprine-­induced bicytopenia,intravenous immunoglobulin(IVIG) was initiated. Despite transient disease control, recurrent flares suggested a persistent triggering factor. Specifically, quetiapin was implicated and discontinued with an immediate clinical response. Inadvertent re-­challenge with olanzapine(a related drug)led to a new eruption, confirming drug-­induced BP (DIBP). A total of six IVIG cycles were completed, without severe side effects to report, namely HIV disease progression. HIV-­related autoimmune bullous diseases are rare. Treatment of severe drug eruptions is primarily based on immunossupressive drugs, raising concerns regarding additional immunossupression. This case suggests IVIG as a valuable option for the treatment of BP in HIV patients. In addition, quetiapin should be added to the list of neuroleptics previously linked to DIBP.

Absence of clinical abnormalities suggesting renal involvement during the long-term course of visceral Leishmaniasis

Abnormalities of renal function have been demonstrated inpatients with visceral leishmaniasis; although there was a trend toward normalization following antiparasitic therapy, some abnormalities persisted. With thepurpose of studying the long- term clinical course of renal involvement in visceral leishmaniasis, 32 patients with a diagnosis of this parasitic disease were evaluated in the endemic area and at least 6 months after the clinical cure of the disease and compared with a control group of 28 individuals. No patient had a history or clinical findings suggestive of renal disease and all were normotensive. Laboratory evaluation was normal in all except 3 patients with abnormal urinalysis. Mild proteinuria and microscopic hematuria were seen in a single urinalysis in one patient (although three other urinalysis were normal), and leucocyturia in two female patients. It was concluded that the renal involvement in visceral leishmaniasis is mild and transient, with normal renal function observed on long-term follow-up after cure of the parasitic infection.

Time series morphological analysis applied to biomedical signals events detection

Dissertation submitted in the fufillment of the requirements for the Degree of Master in Biomedical Engineering

Tetanus as a cause of acute renal failure: possible role of rhabdomyolysis

To study the frequency and examine the role of rhabdomyolysis in the acute renalfailure in tetanus 18 patients with the diagnosis of generalized tetanus consecutively admitted to the infectious disease hospital were evaluated. Ofthese 14 were male and 4female with mean age of 31.8± 2.0 years. Except for mild proteinuria recorded in 9 patients, the urinalysis were unremarkable. Serum creatinine higher than 1.4mg/dl was recorded in 39% of the patients, abnormal levels of CPK in 87,5% and serum myoglobin greater than 120µg/l in 39% of the patients. Oliguria was documented in one patient and none required diafysis therapy. No correlation wasfound between renal failure and myoglobin and/or CPK serum levels. Acute renalfailure in tetanus was not infrequent; usualfy it was non-oliguric, mild and transient and not related to the severity of the disease or to serum levels of myoglobin and/or CPK.

Molecular tools to dissect the role of Dmrt2a and Dmrt2b in the left-right axis formation in zebrafish

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina

Target-specific multiphysics modeling for thermal medicine applications

Dissertation to obtain the degree of Doctor of Philosophy in Biomedical Engineering

Bone marrow fibrosis (pseudo-myelofibrosis) in human kala-azar

Thirty cases of human kala-azar were diagnosed by iliac crest biopsy and myeloculture. Histological analysis of 12 patients showed diffuse thickening of reticulin fibers. To the best of our knowledge, this is the third report describing secondary bone marrow fibrosis (myelofibrosis-like) associated with kala-azar. Patients with positive bone marrow fibrosis (pbmf = 12) were compared to patients without detectable bone marrow fibrosis (wbmf = 18). There were no significant differences in clinical and blood parameters following treatment. All patients showed regression of hepatosplenomegaly.Our findings suggest that associated bone marrow fibrosis is transient and did not interfere in the evolution of treated patients.

Aplastic crisis caused by parvovirus B19 in an adult patient with sickle-cell disease

We describe a case of aplastic crisis caused by parvovirus B19 in an adult sickle-cell patient presenting with paleness, tiredness, fainting and dyspnea. The absence of reticulocytes lead to the diagnosis. Anti-B19 IgM and IgG were detected. Reticulocytopenia in patients with hereditary hemolytic anemia suggests B19 infection.

Serial heart rate changes in rats inoculated by conjunctival instillation of Trypanosoma cruzi obtained from bug faeces

The cardiac effects of experimentally induced myocarditis, when the parasite is obtained from mouse blood, are well known. However, the consequences of the infection when the parasites are obtained from bug faeces are less well defined. In the present investigation, we have used the "Y" strain of Trypanosoma cruzi, which was maintained in Rhodnius prolixus by repeated passages in mice. The faeces of 30 infected bugs were collected, the number of parasites counted and 4,000 parasites inoculated by the conjunctival route in 60 rats. Twenty-nine other rats received faeces from noninfected bugs (sham-inoculated controls) and 40 were used as normal controls. The heart rate of the three groups of animals was recorded under general anesthesia with ether. The heart rate, at day 0 pre-inoculation, was similar in the three groups of animals (Controls: 379 ± 27 beats/min Mean ± SD; Sham-inoculated: 366 ± 31; Infected: 351 ± 29) (p> 0.05). In the infected animals, the mean heart rate began to increase significantly by day 12 following infection (375 ± 31), reaching the highest values between days 18 (390 ± 33) and 21 (403 ± 33) and returned to baseline by day 30 (359 ± 28) (p< 0.05). The heart rate changes were statistically different from those observed in the sham-inoculated controls and in the control animals. Therefore, these heart rate changes were provoked by the Trypanosoma cruzi-induced infection. Thus, it appears that irrespective of the source of the parasite and route of inoculation Trypanosoma cruziacute infection provokes a transient sinus tachycardia.

Human parvovirus B19 infection in HIV-positive patients

Parvovirus B19 infects predominantly erythroid cells, leading to transient inhibition of erythropoiesis. Immunocompromised patients may be unable to produce neutralizing antibodies and may develop severe chronic anemia. Epidemiological studies done on Niterói population showed that B19 infection occurs periodically in late spring and summer. We report a study from 55 HIV infected patients attending an infectious diseases outpatient clinic in this city during a 5-month period in which B19 circulation was well documented. All patients were under anti-retroviral therapy. No anti-B19 IgM was found, but a high prevalence of IgG anti-B19 (91%) was observed. In six patients, B19 DNA was found by dot-blot hybridization techniques, but this was not confirmed by PCR. None of these 6 patients manifested anemia and only one had CD4 cell count below 200 x 10(7)/L. We conclude that persistent infection causing anemia is an infrequent finding in our HIV positive patients under drug therapy.