Visceral leishmaniasis (VL), also known as kala-azar, is an important public health problem. If not treated, virtually all clinically symptomatic patients die within months. The diagnosis is based on the Montenegro skin test (MST) and anti-Leishmania titers. Nevertheless, the time required for cured individuals living in a leishmaniasis-endemic area to present a positive skin test and negative anti-Leishmania serology is known. To determine the cellular and humoral immune response profile in relation to different times post-VL cure, a cross-sectional study was conducted on subjects from a kala-azar endemic area in Paço do Lumiar, MA, Brazil, on the basis of 1995-2005 notifications reported by the National Health Foundation/Regional Coordination of Maranhão. We visited cured individuals with a history of VL within the last 10 years. Seventy-four subjects (30 females) ranging in age from 1 to 44 years were included, all of them symptom free at the time of the study. A cellular immune response was observed in 73 (98.6%) subjects, whereas no significant antibody titers were detected by indirect immunofluorescence (IIF) in the sera of 69 (93.2%) cases. Ten years post-cure, 39 (52%) subjects had a positive MST and negative IIF reaction, while in one subject the skin and anti-Leishmania serology tests were negative. Two other subjects were positive in both tests 1 year after cure. These data suggest that a cellular immune response may still be present in subjects cured of VL regardless of post-cure time, and that the parasite persists in the host after clinical cure of the disease. This would explain the persistence of significant Leishmania sp antibody titers in some subjects after treatment.

Pastilhas PDC (polycrystalline diamond compact) são compósitos diamantados, onde o suporte de metal duro (WC/Co) absorve a energia de impacto sofrida pela camada diamantada, aumentando a vida útil da ferramenta. A pastilha é formada através da compactação e sinterização de pós de diamante com materiais ligantes (cobalto) utilizando técnicas de alta pressão e alta temperatura (HPHT). Esta ferramenta é utilizada para corte e usinagem, e em perfuração de poços de óleo e gás (brocas). Face à questão estratégica industrial, poucos estudos foram publicados sobre o processamento e caracterização destas ferramentas. Neste tocante, este trabalho visa o estudo da influência de alguns parâmetros de corte no desgaste dos cortadores PDC, simulando a situação de corte, quais sejam: forças sobre o cortador, temperatura na zona de corte, rotação da mesa de granito e ângulo de corte. Correlacionando estes parâmetros, descobrem-se quais deles influenciam mais no desgaste das pastilhas. Os ensaios foram realizados em um simulador físico de corte e abrasão que forneceu os resultados para análise. No presente estudo, a condição de corte que propiciou melhores resultados, foi 15kgf/30rpm/10º, onde se obteveram-se os menores valores de desgaste - 0,00002g.

PCD bits (poly-crystalline diamond) are composites in which the hardmetal (WC/Co) base absorbs the impact loading, thus increasing the PCD lifetime. The bit is processed by the high pressure - high temperature sintering (HPHT) of a mixture monocrystalline of diamond powders with a binder phase, usually cobalt (Co). This tool is used in cutting and grinding operations, as well as in oil and gas holes drilling. This work deals with the study of the influence of some cutting parameters on the PCD bit's wear, simulating the real drilling operation in a cutting and abrasion physical simulator, wich are: loads on the bits, cutting edge temperature, granite base rotation, and bit cutting angles. In this work, the smoothest wear condition was 15kgf/30rpm/10º - 0.00002g.

Coroas abrasivas são ferramentas de desbaste e polimento utilizadas no beneficiamento de pedras ornamentais, tais como mármore e granito, com o objetivo de promover acabamento final.Foram preparadas uma série de coroas a base de poliéster com 85, 80 e 75% (em peso) de sílica. Após a mistura da sílica abrasiva com a matriz de poliéster, procedeu-se a posterior cura em moldes com o formato das coroas industriais. Os testes finais foram feitos a nível industrial em empresa do ramo, os quais foram acompanhados via medidas de rugosidade do material trabalhado. A partir da diminuição nas dimensões da coroas abrasivas, e perda de massa, mediu-se o desgaste. Os resultados mostraram que as coroas abrasivas de sílica (quartzo) embebidas em poliéster, podem ser utilizadas como ferramentas abrasivas comerciais, resultando em um produto alternativo, de baixo custo e de qualidade satisfatória, quando comparadas às coroas comerciais de SiC-Sorel.

Abrasive crowns are grinding (thinning) and polishing tools used on ornamental rock preparation, like marble and granite, with the objective of promoting a good finish. A series of crowns were prepared using polyester with 85, 80 and 75% (in weight) of silica in the form of quartz, cured in moulds in the shape of industrial crowns. The final tests were made using the industrial facilities of a company specializing in ornamental rock production. Measurements of the surface roughness were performed. The wearing performance of the abrasive crowns was assessed by measuring the reduction in its dimensions. The results showed that the silica (quartz) embedded in polyester crowns can be used as commercial abrasive tools resulting in an alternative product of satisfactory quality. The silica-polyester crowns presented a smaller weight loss than commercially available crowns, resulting in a longer useful life of the tool while providing a similar surface quality in the case of the 85% silica crowns.