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Objetivo: Identificar e revisar as causas de infecções hospitalares associadas a bacilos gram-negativos não fermentadores (BGN-NF) em unidade de terapia intensiva (UTI) e seus métodos de controle e prevenção. Revisão bibliográfica: A taxa de infecção por estes microrganismos é baixa quando comparadas com outros grupos bacterianos, no entanto, se tornam graves pelo fato da alta resistência aos fármacos antimicrobianos. Além disso, fatores como o ambiente físico e tempo de internamento são aspectos ideais para a colonização por estes tipos de bactérias. A diversidade e disseminação podem ser ocasionadas pelo grande fluxo de pacientes submetidos a cirurgias, doença de base, uso dos cateteres urinários e venosos, ventilação mecânica, perfil imunológico, idade e o uso de medicamentos imunossupressores, como também o tratamento empírico com antibióticos e seu uso de forma inadequada podem tornar os pacientes suscetíveis a infecções. Considerações finais: Medidas constantes de esterilização do ambiente e de materiais utilizados para a reabilitação em UTI são fundamentais para a redução do agravamento das taxas de mortalidade em decorrência desta problemática, possibilitando a limitação de aparecimento de microrganismos resistentes aos atuais fármacos existentes, reduzindo assim problemas relacionados a assistência à saúde.

Neste trabalho foram produzidas camadas de boretos de elevadas durezas e resistências ao desgaste nos aços AISI H13 e AISI D2, por meio de tratamento termo-reativo em banho de bórax com adição de 10% de alumínio. Posteriormente foram realizados tratamentos pela técnica PVD sobre as camadas de boretos. As amostras foram caracterizadas por meio de microscopia óptica, microscopia eletrônica de varredura, ensaios de dureza e ensaios de micro desgaste abrasivo com esfera livre. Para ambos os materiais, os tempos de tratamento de boretação foram de 4 horas, seguido de resfriamento em óleo ou ao ar. As camadas produzidas por boretação no caso do aço AISI H13 apresentaram espessura média de 70 μm e para o aço AISI D2 espessura média de 100 μm. As durezas das camadas de boretos produzidas variaram de 1500 a 1700 HV. Os ensaios de micro desgaste abrasivos com esfera livre foram realizados com uso de solução abrasiva de carboneto de silício. Todas as camadas produzidas apresentaram resistências ao desgaste muito superiores as dos substratos. As amostras com tratamentos duplex boretação-PVD apresentaram os melhores desempenhos ao desgaste, seguidas pelo aço AISI D2 e AISI H13 boretados e por último os aços AISI D2 e AISI H13 temperados e revenidos. Borides layers with high hardness and wear resistances were produced on AISI H13 and AISI D2 steels by thermo-reactive treatment in borax added with 10% of aluminum. Subsequently, treatments by the PVD technique were performed on the layers of borides. The samples were characterized using Optical Microscopy, Scanning Electron Microscopy, hardness testing and free-ball micro abrasive wear test. For both materials, the boriding treatment times were 4 hours long, followed by cooling in oil or air. In the case of AISI H13, the layers produced by boriding showed an average thickness of 70 μm while AISI D2 steel presented an average thickness of 100 μm. The hardness of the produced boride layers ranged from 1500 to 1700 HV. The micro abrasive wear tests were performed using abrasive solution of silicon carbide. All produced layers showed wear resistance much higher than the substrates. Samples with treatments duplex PVD-boriding presented the best wear performances, followed by AISI D2 and AISI H13 borated steels and finally, AISI D2 and AISI H13 steels quenched and tempered.

Nitretacao a plasma e um processo de tratamento termoquimico que consiste em um endurecimento superficial, provocado pela difusao intersticial de nitrogenio atomico nas superficies de ligas metalicas. Neste trabalho, este processo foi empregado na modificacao superficial de uma liga de ferro sinterizado. Foram feitos analises via microscopia eletronica de varredura (MEV) e difracao de raios X (DRX) em amostras submetidas ao tratamento de ferroxidacao e ao tratamento a plasma, realizado sob diferentes condicoes de tempo e temperatura. Os resultados mostraram que a espessura da camada de nitreto formada e maior para todas as amostras nitretadas em comparacao a amostra ferroxidada, e a mesma aumenta com o tempo e temperatura de nitretacao, sendo a temperatura a variavel que mais influencia. Tambem, resultados identificaram que a camada nitretada, para todas as amostras, proxima a regiao superficial consiste de uma mistura de fases de Fe4N e Fe3N.

Stainless steels are widely used in chemical and other industries due to their corrosion resistance. However, because of their low hardness and wear properties, their applications are limited. Many attempts have been made to increase the surface hardness of these materials by using plasma techniques. Plasma nitriding is distinguished by its effectiveness, and for presenting a relatively low cost and being a clean process, producing hard surface layers on stainless steels. Aiming to verify the influence of the temperature and pressure on the modified resultant layers, samples of AISI 316 and 409 stainless steels were plasma nitrided in two different temperatures (450 and 500°C) and pressures of 400, 500, and 600 Pa for 5 h. After the nitriding treatment, the layers were analyzed by means of optical microscopy and wear tests. Wear tests were conducted in a fixed-ball micro-wear machine without lubrication. After the plasma nitriding treatment on AISI 316 and 409 samples, homogeneous and continuous layers were produced and their thicknesses increased as the temperature increased and as the pressure decreased. The nitriding treatment on the AISI 316 steel resulted on the formation of expanded austenite layers at 450°C and chromium nitrides (CrN and Cr2N) phases at 500°C. The nitriding treatment on AISI 409 yielded the formation of similar layers for both treatment temperatures; these layers constituted mainly chromium (Cr2N) and iron (Fe2N, Fe3N, and Fe4N) nitrides. After the nitriding treatment, the AISI 316 steel sample presented higher wear resistance for lower temperature and pressure values. The increase on layer fragility, for higher temperature and pressure values, can be responsible for this inverse tendency. The wear resistance of the nitrided AISI 409 sample followed a logic tendency: the harder the layer, the better the performance, i.e., the performance was improved with the increase in both the temperature and pressure.

The superiority of superaustenitic stainless steel (SASS) lies in its good weldability and great resistance to stress corrosion and pitting, because of its higher chromium, molybdenum, and nitrogen contents, when compared to general stainless steels. However, some of its applications are limited by very poor wear behavior. Plasma-nitriding is a very effective treatment for producing wear resistant and hard surface layers on stainless steels without compromising the corrosion resistance. In this work, UNS S31254 SASS samples were plasma-nitrided at three different temperatures (400, 450, and 500 °C), under a pressure of 500 Pa, for 5 h, in order to verify the influence of the temperature on the morphology, wear, and corrosion behavior of the modified surface layers. The plasma-nitrided samples were analyzed by means of optical microscopy, micro-hardness, X-ray diffraction, wear, and corrosion tests. Wear tests were conducted in a fixed ball micro-wear machine and corrosion behavior was carried out in natural sea water by means of potentiodynamic polarization curves. For the sample which was plasma-nitrided at 400 °C, only the expanded austenite phase was observed, and for the treatments performed at 450 and 500 °C, chromium nitrides (CrN and Cr2N) were formed in addition to the expanded austenite. Wear volume and Knoop surface hardness increased as the plasma-nitriding temperature increased. Higher wear rates were observed at high temperatures, probably due to the increment on layer fragility. The sample modified at 400 °C exhibited the best corrosion behavior among all the plasma-nitriding conditions.

Science competitions, such as the Brazilians Physic, Mathematical, Chemical, Astronomy and Biology Olympiads, are becoming popular and every year thousands of students from basic to high schools are attracted to participate motivated by the challenges. These competitions are becoming powerful criteria to evaluate the education system as well.Since 2006 the Instituto de Fisica de Sao Carlos is the institution that coordinates the Brazilian Physics Olympiad (OBF) at Sao Paulo state. Parallel with the regular calendar of the OBF, activities such as: visits, courses, seminars were happens and opened to all community. In this paper we analyze the results of these activities as a way to promote the knowledge dissemination produced in the University.