Abstract This paper compares the creep behavior of Ti-6Al-4V alloy after different surface treatments, the plasma nitriding using Plasma Enhanced Chemical Vapor Deposition (PECVD), and the deposition of SiC thin films with Cr interlayer using High Power Impulse Magnetron Sputtering (HiPIMS). A microstructural characterization was performed with Scanning Electron Microscopy (SEM), Scanning and Transmission Electron Microscopy (STEM), and Energy Dispersive Spectroscopy (EDS) techniques. The creep test was performed at a constant load from 500 to 600 °C and 125 to 319 MPa, and a fractographic analysis was performed. The EDS analysis of the plasma nitrided layer indicated the nitrogen presence of the compounds TiN and Ti2N and an increase in the iron concentration. Creep test results in both conditions indicated an increase in the creep resistance. Plasma nitrided condition indicated the lowest creep rate and lesser elongation, making it the most suitable in applications that require a low dimensional distortion.

Resumo Este estudo tem como objetivo avaliar a influência da adição de esporos de B. subtilis AP91 nas propriedades mecânicas de argamassas. Para tanto, a bactéria B. subtilis AP91 isolada de folhas de arroz da variedade agulha precoce foi utilizada na concentração de 105 esporos/mL em argamassas com traço de 1:3 (em massa) e relação água/cimento (a/c) de 0,63. Os esporos bacterianos foram adicionados de duas diferentes formas: na água de amassamento e por imersão em solução contendo os esporos. A análise por Microscopia Eletrônica de Varredura (MEV) com Sistema de Energia Dispersiva (EDS) mostrou cristais com picos de cálcio, o que possivelmente indica a presença de carbonato de cálcio bioprecipitado. Os resultados obtidos a partir da análise mecânica mostraram que a bioprecipitação de CaCO3 pela bactéria B. subtilis AP91 foi satisfatória, particularmente quando os esporos foram adicionados à água de amassamento, aumentando a resistência à compressão em até 31%. Portanto, conclui-se que a adição de esporos de B. subtilis AP91 na água de amassamento das argamassas induziu a biocimentação, que aumentou a resistência à compressão. A bioprecipitação de carbonato de cálcio pode ter outras consequências benéficas, como o fechamento de poros e fissuras em materiais cimentícios, que poderiam melhorar a durabilidade, embora mais pesquisas neste aspecto ainda sejam necessárias.

Abstract This study aims to evaluate the influence of B. subtilis AP91 spores addition on the mechanical properties of mortars. B. subtilis strain AP91, isolated from rice leaves of the needle variety, which has an early cycle of production, was used at the concentration of 105 spores/mL in mortars with cement-to-sand ratio of 1:3 (by weight) and water-to-cement ratio (w/c) of 0.63. These spores were added in two different ways: in the mixing water and by immersion in a solution containing bacterial spores. Scanning Electron Microscope (SEM) analysis showed crystals with calcium peaks on the EDS, which possibly indicates the presence of bioprecipitated calcium carbonate. The results obtained in the mechanical analysis showed that the bioprecipitation of CaCO3 by B. subtilis strain AP91 was satisfactory, particularly when the spores were added in the mixing water, increasing the compressive strength up to 31%. Thus, it was concluded that the addition of B. subtilis AP91 spores in the mixing water of cement mortars induced biocementation, which increased the compressive strength. This bioprecipitation of calcium carbonate may very well have other advantageous consequences, such as the closure of pores and cracks in cementitious materials that could improve durability properties, although more research is still needed on this matter.

Introduction: The aim of this work was to study the accuracy of the CKD-EPI equation to estimate the glomerular filtrate in patients with advanced chronic renal failure. Objective: We compared the estimations of Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockcroft-Gault (CG) equations to a glomerular filtration rate measured as the arithmetic mean of the urea and creatinine clearances (ClUrCr). Material and methods: The study was made in 89 nondialyzed patients with chronic renal disease in stage 4 or 5. Serum creatinine values were recalibrated to standardized creatinine measurements. In each patient, the difference between each estimating equation and the measured glomerular filtration rate was calculated. The absolute difference expressed as a percentage of the measured glomerular filtration rate indicates the intermethod variability. Results: Overall, the glomerular filtration rate measured as the ClUrCr was 14.5 ± 5.5 ml/min/1.73 m²; and the results of the estimating equations were: MDRD 14.3 ± 5.5 (p = NS); CKD-EPI 13.6 ± 5.4 (p <0.01) and CG 16.8 ± 6.5 ml/min/1.73 m² (p <0.001). The variability of the estimating equations was 16 ± 12.2%, 16.7 ± 12,1% and 22 ± 15.6% (p <0.05), for MDRD, CKD-EPI and CG. The percentage of estimates within 30% above or below the measured glomerular filtration rate was 85% for MDRD, 88% for CKD-EPI and 70% for CG. The CG variability, but not MDRD variability or CKD-EPI variability, was influenced by gender (19.3 ± 15.1% in males vs 27.3 ± 15.5% in females, p <0.05) and showed a negative correlation with the glomerular filtration rate (r = -0. 23, p <0.05) and the age (r = -0.24, p <0.05) and positive correlation with the body mass index (r = 0.37, p <0.001). In patients with chronic renal disease in stage 5, the variability of the different estimating equations was similar. Conclusions: We conclude that in our population with advanced chronic renal failure, the CKD-EPI equation is as accuracy as the MDRD equation. With standardized creatinine the CG equation has a lower accuracy and its utilization may be reconsiderated.

Introducción: La ecuación clásica Modification of Diet in Renal Disease (MDRD) subestima el filtrado glomerular en los valores más altos. Para aumentar su concordancia en los estadios 1 y 2 de la enfermedad renal crónica se ha establecido una nueva fórmula: la ecuación Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). Objetivo: El objetivo del presente estudio es comprobar si la nueva ecuación es mejor que la MDRD en la estimación del filtrado glomerular en la insuficiencia renal crónica avanzada, en una población como la nuestra que tiene unas características antropométricas distintas de las de la población norteamericana. Material y métodos: En 89 pacientes con enfermedad renal crónica en estadios 4 y 5, hemos estudiado el grado de concordancia entre el filtrado glomerular medido como la media de los aclaramientos de urea y creatinina (AclUrCr) y el estimado por las ecuaciones MDRD, CKD-EPI y Cockcroft-Gault (CG). La concentración de creatinina corresponde a creatinina estandarizada. La variabilidad de cada una de las ecuaciones fue estudiada mediante la diferencia relativa (diferencia absoluta con el AclUrCr expresada como porcentaje de la media entre el AclUrCr y la ecuación analizada). Resultados: El filtrado glomerular medido por el AclUrCr y el estimado por las ecuaciones MDRD, CKD-EPI y CG fue respectivamente de 14,5 ± 5,5, 14,3 ± 5,5, 13,6 ± 5,4 y 16,8 ± 6,5 ml/min/1,73 m². No hay diferencia estadísticamente significativa del AclUrCr con la ecuación MDRD, pero sí con la ecuación CPK-EPI (p <0,01) y con la ecuación CG (p <0,001). La variabilidad de las diferentes ecuaciones con respecto al AclUrCr fue de 16 ± 12,2%, 16,7 ± 12,1% y 22 ± 15,6%, para las ecuaciones MDRD, CKD-EPI y CG, respectivamente (p <0,01 entre la ecuación CG y las dos ecuaciones previas). El porcentaje de mediciones que se encontraban dentro del 30% por encima o por debajo del valor conseguido con el método de referencia fue del 85% de las realizadas con la ecuación MDRD, del 88% con la ecuación CKD-EPI y del 70% de las realizadas con la ecuación CG. La variabilidad de las ecuaciones MDRD y CKD-EPI no se ve influida por el sexo, ni se correlacionó con la edad, el índice de masa corporal ni con el filtrado glomerular medido como AclUrCr. Por el contrario, la variabilidad de la ecuación CG era menor en hombres (19,3 ± 15,1 frente a 27,3 ± 15,5%; p <0,05) y tenía una correlación negativa con la edad (r = -0,24; p <0,05) y con el filtrado glomerular (r = -0,23; p <0,05), y positiva con el índice de masa corporal (r = 0,37; p <0,001). Conclusiones: Podemos concluir que en nuestra población con insuficiencia renal crónica avanzada, la ecuación CKD-EPI tiene una equivalencia con el filtrado glomerular medido como la media de los aclaramientos de urea y creatinina, similar al de la ecuación MDRD. Con la creatinina estandarizada, la ecuación CG pierde concordancia y su utilización debe ser reconsiderada.

Half of patients starting chronic hemodialysis used a transient vascular catheter as a vascular access (unplanned initiation). An objective of the Quality Management Group of the Spanish Society of Nephrology is to achieve that 80% of the patients starting hemodialysis do it with an arteriovenous fistula. We want to review the causes of non-planned hemodialysis nowadays. In 2010, 43 patients had started chronic hemodialysis in the Hospital Ramón y Cajal in Madrid (Spain). Mean age was 61 years, 79% were men, the most frequent cause of chronic renal disease was the diabetes (23%) and Charlson Comorbidity Index was 6.3 ± 2.6. The unplanned hemodialysis occurred in 20 patients (47%), without any differences with the 23 patients who began planned hemodialysis, in none of the clinical or demographic parameters analyzed. The main cause of unplanned hemodialysis was the acute exacerbation of chronic kidney disease stage 3 or 4, previously stable, secondary to an unforeseeable intercurrent process (8 patients, 40% of the cases). One patient began after a non-recovery acute renal failure and in other 6 patients, the reason of unplanned hemodialysis initiation was not attributable to the operation Health System (in 3 cases unknown kidney chronic disease and in the other 3 cases it was patient´s responsibility). Only in 5 cases (25%), the cause could be corrigible. Most causes of unplanned hemodialysis does not come from the healthcare organization and therefore not easy to resolve it. Consequently, the objective of the Quality Group will be difficult to be achieved.

La mitad de los enfermos que comienzan tratamiento con hemodiálisis periódica lo hacen con un catéter venoso como acceso vascular (inicio no programado). Un objetivo del Grupo de Gestión de Calidad de la Sociedad Española de Nefrología es conseguir que el 80% de los enfermos comiencen la hemodiálisis a través de una fístula arteriovenosa. Hemos querido revisar las causas que condicionan en la actualidad el inicio no programado, para analizar cuáles pueden ser corregibles. En el año 2010, 43 enfermos comenzaron tratamiento con hemodiálisis periódica en el Hospital Ramón y Cajal de Madrid. La edad media fue de 61 años, el 79% eran hombres, la etiología más frecuente fue la diabetes mellitus (23%) y el índice de Charlson era de 6,3 ± 2,6. El inicio no programado de la hemodiálisis ocurrió en 20 enfermos (47%), sin objetivarse diferencias con los 23 enfermos que comenzaron hemodiálisis de forma programada, en ninguno de los diferentes parámetros clínicos o sociodemográficos analizados. La causa más frecuente de inicio no programado fue la reagudización de una enfermedad renal crónica en estadio 3 o 4, previamente estable, por un proceso intercurrente imprevisible (ocho enfermos, 40% de los casos). Un enfermo comenzó hemodiálisis periódica por un fracaso renal agudo no recuperado y en otros seis el motivo de inicio no programado no fue achacable al funcionamiento del sistema sanitario (enfermedad renal crónica no conocida en tres casos y causas achacables al propio enfermo en otros tres). Solamente en el 25% de todos los casos (cinco enfermos), la causa de inicio no programado pudo ser corregible. La mayoría de las causas de inicio no programado de hemodiálisis son ajenas a la organización sanitaria y, por tanto, difíciles de subsanar. Estas circunstancias deben tenerse en cuenta cuando se revisen los objetivos del Grupo de Gestión de Calidad.

O presente estudo avalia a resposta de cepas de Plasmodium falciparum às drogas antimaláricas, através de testes in vitro, isoladas em 7 municípios do sul do Estado do Pará. Foram efetuados 69 testes para cloroquina e mefloquina, 62 para amodiaquina e 61 para quinino. Os resultados mostram elevada resistência para cloroquina (71%), relativamente baixa resistência para amodiaquina com (25,8%) e para o quinino apenas 8,2%. Mefloquina revela ampla sensibilidade (100%), mas, demonstrando perda da mesma quando comparada em dois períodos distintos. Evidenciou-se também cepas multirresistentes em dois dos municípios estudados.

The responses of Plasmodium falciparum to antimalarial drugs were evaluated through the in vitro test using blood sample collected from patients of 7 municipalities of the south of Pará State. Sixty nine microtests for chloroquine and mefloquine, 62 for amodiaquine and 61 for quinine were pet formed. The results showed a high resistance for chloroquine (71%), a relatively low resistance level for amodiaquine (25.8%) and little resistance to quinine (8.2%). For mefloquine 100% of sensitivity was found.

Foram realizados 171 testes de sensibilidade (microtécnica) com cepas de Plasmodium falciparum da Região Amazônica brasileira para cloroquina, mefloquina, amodiaquina e quinino. Os testes tiveram duração de 24 horas com as drogas preparadas na hora da realização de cada teste. Os resultados mostraram elevada resistência a cloroquina (83%) e sensibilidade em quase a totalidade das amostras testadas para mefloquina (97,7%). Para amodiaquina e quinino observou-se sensibilidade em 51,0% e 56,5% das cepas, respectivamente. Este estudo demonstra a emergência de um possível foco de resistência do Plasmodium falciparum a mefloquina, em Tucuruí.

Drug resistance tests were performed with 171 strains of P. falciparum obtained from the Amazon Region, using chloroquine, mefloquine, amodiaquine and quinine. Tests lasted about 24 hours and the drug solutions were prepared just before use. Results show high percentage of resistance to chloroquine (83%) whereas nearly all strains were shown to be sensitive to mefloquine (97.7%). For both amodiaquine and quinine sensitivities were of 51.0% and 56.5% respectively. The present study demonstrates that resistance to mefloquine may be starting in Tucuruí, Pará.

Nove amostras de Plasmodium falciparum foram coletadas de migrantes infectados no Estado de Rondônia. Estas amostras foram mantidas em cultivo para caracterização por tipificação enzimática em acetato de celulose, sensibilidade á cloroquina, amodiaquina, mefloquina e quinino e análise da diversidade antigê-nica através de anticorpos monoclonais específicos. Os resultados obtidos mostraram variação entre todas as amostras estudadas: encontrou-se resistência crescente à cloroquina, resistência intermediária à amodiaquina e quinino e sensibilidade a baixos níveis de mefloquina; apenas dois isolados mostraram sensibilidade a todas as drogas. A tipificação enzimática mostrou presença de parasitas GPI 1 e 2 e ADA 1 e 2, enquanto que para PEP e LDH todas as amostras foram do tipo 1. Sorotipagem com anticorpos monoclonais PSA mostrou presença de três sorotipos diferentes (II, III e IV). Estes resultados mostraram: a) variação entre as amostras para os marcadores analisados; b) nesta região, para o pequeno número de amostras analisadas, não foram observadas diferenças significativas ou novos tipos de parasitas.

Nine samples of Plasmodium falciparum were collected from migrant workers who were infected in the State of Rondônia, Brazil. These samples were maintained in culture for characterization by enzyme typing using acetate cellulose electrophoresis, drug susceptibility to chlo-roquine, amodiaquine, mefloquine and quinine and antigenic diversity analysis using strain specific monoclonal antibodies. The results obtained have confirmed major variation among all samples studied: it was found consistent resistance to chloroquine moderated resistance to amodiaquine and quinine and susceptibility to low levels of mefloquine; only two isolates have shown susceptibility to all drugs in the in vitra assays. Enzyme typing showed presence of both GPI 1 and 2 and ADA 1 and 2 parasites, while for PEP and LDH all samples were type 1. Se-rotyping with PSA monoclonal antibodies showed presence of three different serotypes (II, III and IV). These results confirm: a) variation among samples for markers analysed; b) in this area and for the small number of samples studied, no significant differences or new types of parasites were seen.