Abstract A Brazilian Tensile Strength (BTS) laboratory test for meta-andesite was modeled using a Finite/Discrete Element Method (FDEM or FEM-DEM). These hybrid methodologies allow modeling the transition from continuous to discontinuous that happens on mechanical tests of rock samples. This article presents the calibration and the simulation of BTS tests using some parameters previously calibrated on UCS modeling of the same material. Irazu, a two-dimensional software developed by Geomechanica, was used to simulate the tests based on the tensile strength and the fracture pattern. The model shows that, in BTS test simulation, the mode II (shear) happens mainly on the rock-platen contact. The mode I (traction) rules the fractures on the BTS test as observed in laboratory tests. The model represents, with great fidelity, the results obtained in the physical test.

Abstract Finite/discrete element methods (FDEM) are hybrid numerical models that use algorithms to analyze the transition from continuous to discontinuous. This type of formulation allows modeling physical laboratory tests with greater proximity to reality. This article proposes to simulate the average behavior of a uniaxial compression test campaign. The tests were modeled and calibrated based on the strength and the fracture pattern using Geomechanica Inc. Irazu two-dimensional software. The simulated results were analyzed by the mean standard deviation of approximately 3000 elements in the middle third of the model, the same region where the clip gages are located in the physical test. The obtained results show that FDEM can replicate the laboratory test with great similarity.

ABSTRACT The objective of this study was to evaluate the thermal decomposition profile of 10 wood species from the semi-arid region of Brazil using thermogravimetric analysis (TGA) to investigate their potential as biomass energy sources. First, flash carbonization was carried out in a muffle furnace, in which wood samples were heated to a maximum temperature of 500°C, and the product yields were determined. The chemical analysis of the wood of each species for the determination of extractive, lignin and ash contents was performed. TGA was performed using sawdust samples heated at 10°C.min−1 up to 625°C under a nitrogen atmosphere at a flow rate of 50 mL.min−1. The thermal decomposition profile was used to evaluate which wood species was more thermally stable. Mimosa tenuiflora and Poincianella pyramidalis woods were the most suitable as biomass energy sources for charcoal production because of their thermal stability and satisfactory carbonization yields. The thermal stability of the 10 wood samples was confirmed by the analysis of the carbonization yields.

Abstract Mining projects are often budgeted in millions of dollars, making it of interest to the investor to measure a project’s uncertainties and risks, which include the changes in the commodity price. The simulation of asset prices is valid because it enables displaying, with a degree of certainty, the future behavior of a financial asset. One of the most commonly used mathematical forecast models is the Geometric Brownian Motion (GBM) model. This article aims at simulating the forecast price of an iron ore commodity with the GBM method based on the historical price series and comparing it to other forecast approaches used in the financial market. The results of this study indicate that the model has limitations, which should be considered. However, it is an overall good tool to support the economic evaluation of a project, if performed along with other approaches.

RESUMO As operações de processamento secundário de madeira geram grande quantidade de particulados suspensos no ar. A inalação desse material pode estimular o aparecimento de doenças respiratórias nos trabalhadores expostos nestes ambientes de trabalho. No entanto, no Brasil ainda não há um limite de tolerância definido para partículas de madeira suspensas, necessitando de estudos para embasamento técnico e definição desse limite. Objetivou-se mensurar a concentração e dimensão das partículas de madeira de Eucalyptus spp. suspensas no ar em marcenarias. A análise da concentração das partículas suspensas foi desenvolvida pela utilização de bomba gravimétrica e coletores com filtros. Para dimensionar as partículas suspensas no ar usou-se lâminas, microscópio e fotografias. Os dados foram coletados na lixadeira, serra circular e serra fita, em cinco marcenarias semelhantes, no estado do Espírito Santo. Os particulados mais danosos à saúde humana foram provenientes da lixadeira, que pela pequena dimensão facilitam a deposição nas partes mais prejudiciais ao trato respiratório humano. Constatou-se que as concentrações de partículas suspensas encontradas estão acima dos limites recomendados pelas normas internacionais. Diante do risco de danos severos a saúde, há a necessidade urgente e imprescindível de implementação de medidas para redução dos níveis de exposição (EPC e EPI), bem como a implementação de normatização específica com limites de exposição máximo definidos para o setor no Brasil.

ABSTRACT Wood secondary processing operations generate large amounts of airborne particulates. Inhalation of this material can lead to the development of work-related respiratory diseases. The Brazilian legislation does not define threshold limit values for airborne wood particles, and local studies are required to provide a technical basis for establishing these limits by regulation. This study aimed to determine the concentration and size of airborne wood particles of Eucalyptus spp. in woodworking shops. Analysis of the concentration of airborne particles was carried out using a gravimetric sampling pump and collector filters. The size of airborne particles was determined using microscope slides and an optical microscope coupled to an image capture system. Air samples were collected near different machines (belt sander, table saw, and band saw) at five woodworking shops located in the state of Espírito Santo, Brazil. Of the three machines, the belt sander produced the most harmful type of particulate matter: the small size of these particles allows their deposition deep into the respiratory tract. Particulate matter was above the threshold limit value established by international standards. To prevent the risk of severe health effects, there is an urgent and imperative need to reduce worker exposure levels (by the use of collective and personal protective equipment) as well as for the implementation of specific regulations that define particulate exposure limits for the wood sector in Brazil.

WC/Co is widely used as cutting tools, because has a unique combination of high strength, hardness, toughness, and moderate stiffness, especially with fine grained WC and finely distributed cobalt. WC/Co powder mixture sinters by different methods such as vacuum sintering, microwave sintering and SPS. High pressure high temperature (HPHT) sintering is a proposed method that can result in better distribution of cobalt and avoid undesirable phases by using high pressure, high temperature and very short sintering time. In this study, a powder mixture of WC- 10 wt% Co was sintered by HPHT at 1500 to 1900ºC under a pressure of 7.7 GPa for 2 minutes. Microstructural/structural analyses were performed by SEM/EDS. Hardness and compression test were also done to obtain the effect of sintering parameters. It was found that HPHT sintering method can be used to produce WC/Co hardmetal with low sintering time and high production rate. It was realized that increasing sintering temperature in HTHP sintering method results in increasing density but hardness and compression strength increase by increasing sintering temperature up to 1800 ºC and then decrease.

RESUMO O diboreto de titânio (TiB2) é um material cerâmico que se destaca por sua elevada resistência mecânica, estabilidade química e dureza a altas temperaturas, entretanto, características como baixa sinterabilidade e tenacidade a fratura limitam a atuação deste material em aplicações termomecânicas. Técnicas de sinterização não convencionais como SPS e aditivo de sinterização como AlN e Si3N4 podem reduzir a temperatura de sinterização e aumentar a tenacidade à fratura do TiB2. Neste sentido, o presente trabalho teve como objetivo avaliar a eficiência da técnica de sinterização por plasma pulsado (Spark Plasma Sintering - SPS) no processamento do diboreto de titânio. O nitreto de alumínio foi utilizado como aditivo para reduzir temperatura e tempo de sinterização e facilitar a densificação do TiB2. Os resultados apontam a sinterização por plasma pulsado como uma técnica eficiente na densificação de compósito cerâmico TiB2 - AlN. Elevado grau de densificação foi alcançado mesmo utilizando tempos de sinterização relativamente curto.

ABSTRACT Titanium diboride (TiB2) is a ceramic material that highlight because of its high mechanical resistance, chemical stability and hardness in high temperatures. However, characteristics as low sinterability and fracture toughness restrict its usage on termomechanical applications. Non-conventional sintering techniques as SPS and sintering aid as AlN and Si3N4 can reduce sintering temperature and increase fracture toughness of TiB2. The objective of this work is to evaluate the efficiency of spark plasma sintering (SPS) technique on the manufacturing of titanium diboride. Aluminum nitride (AlN) was used as additive to reduce sintering temperature and time and enhance tib2 densification. The results indicate that spark plasma sintering is an efficient technique in the densification of TiB2 - AlN ceramic composite. High degree of densification was achieved even using relatively short sintering time.

Background: Paroxysmal nocturnal hemoglobinuria is an acquired chronic hemolytic ane- mia, which often manifests as peripheral blood cytopenias and thrombosis. Objective: The aim of this study is to describe a Brazilian population of paroxysmal nocturnal hemoglobinuria patients. Methods: One hundred and three paroxysmal nocturnal hemoglobinuria cases were retrospectively reviewed and the clinical presentation, thrombosis, survival, and clone size were assessed. Diagnosis was established by flow cytometry. Results: Fifty-two male and 51 female patients with a median age of 24.1 years (5.5-62 years) were studied. Clinical symptoms included hemoglobinuria (18.4%), infection (46.6%) and thrombosis (16.5%), and 80.6% had pancytopenia. Patients were classified as classic parox- ysmal nocturnal hemoglobinuria (10), paroxysmal nocturnal hemoglobinuria with aplastic anemia (39), and paroxysmal nocturnal hemoglobinuria with subclinical features and aplas- tic anemia (54). There were significant differences in terms of median age, size of clone, clinical symptoms, and peripheral blood cell counts between the three subcategories. The clone size in erythrocytes and granulocytes were respectively 0.04% (range: 0-18%) and 7.3% (range: 0.3-68.7%) in patients with subclinical features and aplastic anemia, 15.8% (range: 0-99.7%) and 63.0% (range: 1.7-99.8%) in patients with aplastic anemia alone, and 82.2% (range: 0-99.85%) and 98.0% (81.3-100.0%) in Classic disease. Statistical differences were identified for platelets (p-value = 0.001), lactate dehydrogenase (p-value = 0.002) and the clone size (p-value < 0.001) in patients who suffered thrombotic events compared to those who did not. Overall survival was 81.7%, with patients with subclinical features and aplastic anemia having lower overall survival (76.5%). Conclusion: This retrospective review of 103 patients over an 11-year period represents the largest collection of paroxysmal nocturnal hemoglobinuria cases from a single center in Brazil. Flow cytometry showed that a larger clone was associated with classical symptoms and increased risk of thrombosis, even in patients with bone marrow failure, whereas a smaller clone was associated with bone marrow aplasia.

O transplante de células-tronco hematopoéticas (TCTH) é o tratamento de escolha para leucemias agudas de alto risco. Apesar da melhora na sobrevida destes pacientes, a recidiva continua sendo a maior causa de óbito pós-transplante de células-tronco hematopoéticas. O objetivo deste trabalho foi analisar os resultados dos transplantes realizados em crianças com leucemia aguda em duas instituições brasileiras. Realizou-se estudo retrospectivo de 208 pacientes transplantados entre 1990-2007. Mediana de idade: 9 anos; 119 pacientes com leucemia linfoide aguda (LLA) e 89 com leucemia mieloide aguda (LMA). Doença precoce: CR1 e CR2. Doença avançada: >CR3, doença refratária ou recidivada. Noventa pacientes vivos entre 258-6.068 dias (M:1.438), com sobrevida global (SG) de 45% (3 anos) e a sobrevida livre de recaída (SLR) 39% (três anos). 14/195 pacientes tiveram falha primária de pega (8%). Não houve diferença na sobrevida global e sobrevida livre de recaída entre pacientes com leucemia linfoide aguda e leucemia mieloide aguda, entre transplantes aparentados e não aparentados, tampouco entre as fontes de células utilizadas. O desenvolvimento da doença do enxerto contra hospedeiro (DECH) aguda ou crônica também não influenciou a sobrevida global e sobrevida livre de recaída. Pacientes com leucemia linfoide aguda condicionados com irradiação corporal total (TBI) apresentaram melhor sobrevida global e sobrevida livre de recaída (p<0,001). Cento e dezoito pacientes morreram entre 1-1.654 dias pós-transplante de células-tronco hematopoéticas (M:160). Mortalidade relacionada a transplante (MRT) (dia+100): 16%. Incidência cumulativa de recaída: 40% (3 anos). Pacientes com doença avançada tiveram menor sobrevida global e sobrevida livre de recaída (três anos)(p<0,001). Na análise multivariada, o status da doença foi o principal fator associado ao aumento da sobrevida global e sobrevida livre de recaída. Nossos resultados mostram que é possível se atingir uma boa sobrevida para pacientes com doença precoce e também mostram a baixa eficácia naqueles com doença avançada.

Hematopoietic Stem Cell transplantation (HSCT) is the treatment of choice for patients with high-risk leukemia. In spite of this, relapse remains a major cause of death of these patients. Our objective was to analyze the outcomes of patients with acute leukemia submitted to hematopoietic stem cell transplantation in two Brazilian institutions. A retrospective study of 208 patients transplanted between 1990 and 2007 with a median age of 9 years (range: 1-18 years) was made. One hundred and nineteen patients had acute lymphocytic leukemia (ALL) and 89 had acute myeloid leukemia (AML). Early disease was considered for CR1 and CR2 cases and advanced disease >CR3 and refractory and relapse disease. Ninety patients are alive between 258 and 6068 days after hematopoietic stem cell transplantation (M: 1438 days). The overall survival (OS) was 45% (3 years) and event free survival (EFS) was 39% (3 years). Primary graft failure occurred in 14/195 patients (8%). There were no differences in the overall survival and event free survival between patients with acute lymphocytic leukemia and acute myeloid leukemia, between sources of cells used or between those who developed acute or chronic graft-versus-host disease (GVHD). When comparing transplants from related and unrelated donors, there was no difference in the overall survival. Patients with acute lymphocytic leukemia receiving the total body irradiation (TBI) conditioning regimen had better overall survival and event free survival (p<0.001). One hundred and eighteen patients died between 0 and 1654 days after hematopoietic stem cell transplantation (M: 160 days). Transplantation-related-mortality (TRM) at D+100 was 16% and cumulative incidence of relapse was 40% (3 years). Patients with advanced disease had lower 3-year overall survival and event free survival (p<0.001). Multivariate analysis showed that disease status was the most significant factor associated with higher event free survival and overall survival . Our results show that children and adolescents transplanted with early disease can achieve considerable overall survival and also highlights the inefficacy of hematopoietic stem cell transplantation for patients with advanced disease.

Adolescent brain development seems to be important for the maturation of brain structures and behavior. Intermittent binge ethanol drinking is common among adolescents, and this type of drinking can induce brain damage and cognitive deficits. In addition, emotional changes are frequently seen in alcoholics and rodents treated with ethanol. Considering the close relation between emotional arousal and cognitive responses, the present work investigates if intermittent ethanol binge exposure could differentially alter the performance of adolescent rats in aversive and non-aversive motivated tests. Male adolescent rats were submitted to ethanol treatment (2.5 or 5.0 g/Kg, o.a.) at 48-h intervals over postnatal day (PND) 30 to 60. Control animals were exposed to a similar administration protocol with saline administration. At PND61-PND63 animals were submitted to one-trial object recognition or contextual and tone fear conditioning paradigms. Binge ethanol drinking (at both 2.5 and 5.0 g/Kg) did not change freezing response in the contextual and tone fear conditioning. However, all doses impaired recognition rates 24h after training in object recognition test. In addition, despite a diminution of horizontal locomotion in the open field (only for the 5.0 g/Kg dose), no difference was detected regarding time in immobility, time in grooming and number of rearing in this paradigm. The present results show that the cognitive impairment resulting from intermittent binge ethanol exposure has a negative correlation with learning-associated emotional arousal.

Apresentamos as complicações neurológicas avaliadas em uma série de 1000 pacientes submetidos ao transplante de células tronco hematopoiéticas (TCTH). As complicações neurológicas do sistema nervoso central foram as mais encontradas, particularmente as hemorragias encefálicas, seguidas por crises convulsivas e por infecções. Uma complicação peculiar foi a encefalopatia de Wernicke. Menos freqüentemente foram encontrados casos de encefalopatia metabólica, síndrome maligna neuroléptica, leucoencefalopatia posterior reversível, infarto cerebral e os distúrbios do movimento. Entre as complicações neurológicas do sistema nervoso periférico a mais encontrada foi a radiculopatia pelo herpes zoster, enquanto que raramente se observaram casos de polineuropatias periféricas, miopatia inflamatória e de miotonia.

We present the neurological complications evaluated in a series of 1000 patients who underwent hematopoietic stem cell transplantation (HSCT). Central nervous system (CNS) neurological complications, particularly brain hemorrhages, were the most common, followed by seizures and CNS infections. An unusual neurological complication was Wernicke's encephalopathy. Less frequent neurological complications were metabolic encephalopathy, neuroleptic malignant syndrome, reversible posterior leukoencephalopathy syndrome, brain infarct and movement disorders. The most common neurological complication of the peripheral nervous system was herpes zoster radiculopathy, while peripheral neuropathies, inflammatory myopathy and myotonia were very rarely found.

A linfohistiocitose hemofagocítica caracteriza-se por ativação e proliferação excessiva de linfócitos e macrófagos. Quando associada à artrite idiopática juvenil é também conhecida por "síndrome de ativação do macrófago", sendo uma complicação potencialmente fatal desta doença. Apresentamos o caso de uma mulher de 26 anos portadora de artrite idiopática juvenil (poliartrite, fator reumatóide negativo), com diagnóstico aos 13 anos, em uso de antiinflamatórios não esteroidais (diclofenaco, nimesulide). Admitida com quadro de resposta inflamatória sistêmica, febre, linfonodomegalia, esplenomegalia, anemia, trombocitopenia, hipofibrinogenemia, hiperferritinemia, hipertrigliceridemia e achados de hematofagocitose na medula óssea. Os autores discutem aspectos relacionados com a patogênese, diagnóstico e tratamento desta doença pouco conhecida.

Hemophagocytic lymphohistiocytosis is characterized by massive lymphocyte and macrophage activation and proliferation. When observed in association with juvenile idiopathic arthritis it is also called "macrophage activation syndrome" being a potentially lethal complication of this disease. We report the case of a 26 years old woman with juvenile idiopathic arthritis (polyarthritis, rheumatoid factor negative) since 13 years old, receiving nonsteroidal anti-inflammatory drugs (diclofenac, nimesulide). She was admitted with systemic inflammatory response, fever, lymph node enlargement, splenomegaly, anemia, thrombocytopenia, hypofibrinogenemia, hyperferritinemia, hypertriglyceridemia and bone marrow hemophagocytosis. Aspects related to pathogenesis, diagnosis and treatment of this little known disease are discussed.