Fatores de virulência de Escherichia coli uropatogênicas provenientes de um Hospital Universitário em Ribeirão Preto, São Paulo, Brasil

The aim of the study was to determine the occurrence of virulence genes expressing fimbriae, production of hemolysin, colicin and aerobactin among a hundred Escherichia coli isolates obtained from in-and outpatients of a tertiary-care teaching hospital, between July and August 2000, showing clinical and laboratory signs of urinary tract infection (UTI). The presence of genes (pap, afa, sfa) for fimbriae expression was assayed using specific primers in a polymerase chain reaction. Among the isolates studied, the prevalence of the virulence factors was 96.0%, 76.0%, 24.0%, for hemolysin, aerobactin and colicin, respectively; the prevalence of genes coding for fimbrial adhesive systems was 32.0%, 19.0% and 11.0% for pap, sfa and afa respectively. The strains isolated from the outpatients displayed a greater number of virulence factors compared to those from hospitalized subjects, emphasizing the difference between these two kinds of patients.O objetivo do trabalho foi determinar a ocorrência de fatores de virulência, tais como, a expressão de fímbrias, produção de hemolisina, colicina e aerobactina em 100 cepas de Escherichia coli isoladas de pacientes ambulatoriais e hospitalizados de um hospital universitário de nível de atendimento terciário, entre os meses de julho e agosto de 2000, que apresentavam sinais clínicos e laboratoriais de infecção do trato urinário (ITU). Foram pesquisados os genes pap, afa e sfa responsáveis pela expressão de fímbrias através da técnica de PCR. A freqüência dos fatores de virulência entre as cepas estudadas foi de 96,0%, 76,0% e 24,0% para hemolisina, aerobactina e colicina respectivamente, e a prevalência dos genes para os sistemas de adesinas fimbriais foi de 32,0%, 19,0% e 11,0% para os genes pap, sfa e afa respectivamente. As cepas isoladas dos pacientes ambulatoriais exibiram um número maior de fatores de virulência quando comparadas com aquelas provenientes de indivíduos hospitalizados

Estimation of uncertainty in analytical balances. Comparison of mass measurements performed in analytical balances (LATU-1999)

The current paper provides the details of the main sources of uncertainty that occur when conventional mass determinations are performed in analytical balances. The data presented correspond to the calibration of 18 analytical balances that belong to LATU, together with the detailed quantification of each of the sources of uncertainty. The results of a comparison of conventional mass measurement performed in those balances with a Teflon sample are assessed, considering their uncertainty values. Conclusions are subsequently drawn on conventional mass measurement´s reproducibility in analytical balances in LATU

Cold Compression Molding of Pyrolytic Carbon from Tires for Oil Absorbers

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Método de Cuckow para la calibración de aerómetros : diseño y puesta a punto del equipo

El método utilizado en el Laboratorio Tecnológico del Uruguay (LATU) para calibración de aerómetros es el “Método de Cuckow para calibración de aerómetros utilizando agua adicionada con un tensoactivo como fluido patrón”. En este método se usa un tensoactivo para bajar la tensión superficial del agua destilada utilizada como fluido patrón y se verifica que la variación en la densidad de la misma, producto del agregado del tensoactivo, contribuye en forma despreciable a la incertidumbre del método y puede ser contemplada dentro de la incertidumbre aceptada para la densidad del agua destilada. Se planificó una estrategia para bajar la incertidumbre de calibración del método; para ello se diseñó un recipiente con un sistema de termostatización con recirculación de agua por camisa, lo que aporta estabilidad térmica al sistema. Se utilizó agitación mecánica para favorecer la termostatización y evitar gradientes de densidad asociados a inhomogeneidad en la temperatura. También se realizaron mejoras en el sistema de ajuste de la lectura y formación del menisco. Luego de estas mejoras se validó nuevamente el método y se demostró que se alcanza la meta propuesta de disminuir las incertidumbres de calibración, estando en condiciones de aplicarlo a calibración de aerómetros de precisión. En el presente artículo se detallan las consideraciones realizadas en el diseño y puesta a punto del equipo mejorado, fundamentalmente el recipiente y el sistema de termostatización. Se plantea la construcción del recipiente a partir de tubos de vidrio disponibles en el mercado, bajando así sus costos. Abstrac The method used in Laboratorio Tecnológico del Uruguay (LATU) for hydrometers calibration is the “Cuckow method for hydrometers calibration using water added with a surfactant as a standard”. A surfactant is used to decrease the surface tension of distilated water used as a standar and is verified that the density variation of distilated water produced by the surfactant adds a small contribution to the uncertainty of the method and can be contemplated within the accepted uncertainty for the density of distilated water. A strategy to reduce the uncertainty calibration of the method was planned; to perform it a container with a system of thermostatization with recirculating water per jacket to provide thermal stabilization to the system was designed, shaking to improve the thermostatization and avoid gradients of density associated with inhomogeneities in the temperature. Improvements were made in the adjustment system of reading and shape of the meniscus. The improved method was validated again and it was demonstrated that improvements help to reduce the uncertainties of calibration, giving the possibility to apply it for calibration of precision hydrometers. In this article considerations in designing and working conditions adjustments of the improved equipment are detailed, mainly in the container and its jacket for recirculating water of thermostatization. This raises its construction with tubes of glass available on the market and lowering the costs

La creación conjunta de videos de matemáticas disponibles en internet

Actualmente la matemática educativa sugiere que los profesores deben desarrollar distintos tipos de conocimientos y habilidades para que la enseñanza rinda los frutos esperados. Nuestra investigación está estrechamente relacionada con la problemática de las prácticas y los procesos de los profesores al usar y diseñar videos educativos de matemáticas (VEM) disponibles en Internet. En ese sentido, abordamos nuestra investigación desde dos problemáticas: (1) la concerniente al uso y diseño de VEM que cristalicen propuestas actuales de investigación y (2) la relacionada con las prácticas y los procesos en los cuales los profesores de bachillerato se involucran al desarrollarlos. La investigación está dividida en dos etapas. La primera, de tipo documental y centrada en los VEM alojados en la plataforma YouTube, sienta las bases para la segunda, de tipo empírica, que tiene como objeto de estudio el uso y producción de VEM por parte de una comunidad de profesores con intereses en común

Simultaneous nitritation-denitritation for the treatment of high-strength nitrogen in hypersaline wastewater by aerobic granular sludge

Fish processing industries produce wastewater containing high amount of salt, organic matter and nitrogen. Biological treatment of such wastewaters could be problematic due to inhibitory effects exerted by high salinity level. In detail, as is known, high salt concentration leads to accumulation of nitrite due to inhibition of nitrite-oxidizing bacteria. The feasibility of performing simultaneous nitritation and denitritation in treating of fish canning wastewater by aerobic granular sludge was evaluated, and simultaneous nitritation-denitritation was successfully sustained up to 50 gNaCl L-1. Nitritation collapsed above which nitritation, and the only nitrogen removal mechanism was represented by heterotrophic synthesis. Conversely, organic matter removal was not affected by salinity, but rather by organic loading rate (OLR). COD fractionation analysis highlighted that aerobic granules exhibited excellent removal capacity toward particulate organic matter. Finally, results obtained in this work pointed out that aerobic granular sludge had excellent ability of adapting in adverse environmental conditions

Splenic metastasis in a bitch affected by an ovarian dysgerminoma - a case report

Dysgerminomas are infrequent neoplasms resulting from undifferentiated germinal cells, mainly observed in the bitch. Our case describes for the first time a dysgerminoma related splenic metastasis in a bitch. A 14-year-old crossbred bitch was admitted at our facility with a 3-month history of irregular oestrous cycle, vulvar swelling, haemorrhagic vaginal discharge, lethargy and anorexia. Cytological examination showed the presence of superficial epithelial cells of the vaginal mucosa with a high degree of cornification. Vaginoscopy showed the typical pale and crenulated mucosal folds (oestrus). Haematological analysis indicated moderate anaemia and leukocytosis, and increased level of oestrogen. Ultrasound examination showed a mass located caudally to the kidney in the region of the right ovary. Abdominal and thoracic radiographs confirmed the findings and did not reveal metastases. Suspecting an ovarian tumour, we decided to perform a complete ovariohysterectomy. Once located, the right ovary presented an increased volume, irregular shape and reddish colour. Samples collected during the procedure were stained with haematoxylin and eosin and observed under optical microscope. The cells were characterized by a scant cytoplasm, a large vesicle type nucleus with coarsely granular chromatin and distinct cell borders. The neoplastic cells were remarkably similar to those of a testicular seminoma, allowing for the diagnosis of ovarian dysgerminoma. Two years after the ovariohysterectomy, the owner reported history of increased volume of the abdomen and lethargy. A second surgery was performed during which an irregular splenic mass was found. The morphological diagnosis was "splenic metastasis of dysgerminoma". To the authors' knowledge, dysgerminoma related splenic metastasis was never described in the bitch before

Respirometric assessment of heterotrophic and autotrophic biomass activity in alternate oxic-anoxic MBR pilot plant

The paper reports the main results of an experimental study carried out on a Membrane Biological Reactor (MBR) pilot plant characterized by intermittent aeration. The effect of different aeration/non aeration ratio (TA/TNA) on biomass behavior, in terms of heterotrophic and autotrophic kinetic parameters and active biomass fraction, was studied. Moreover was proposed a method to evaluate the autotrophic active fraction, derived by a combination of the ASM1 model and biokinetic parameters directly evaluated by means of respirometry. The experimental observation outlined that TA/TNA in the cycle didn’t affect heterotrophic biomass kinetic and active fraction. This one instead, resulted strongly depended from the soluble substrate present in the influent wastewater. Furthermore, it was observed that a higher aerated phase within the cycle, may lead to a higher autotrophic biomass active fraction

Ensayo de aptitud realizado en LATU para validación del método de calibración y uso de pipetas de vidrio y pipetas automáticas

En 2008 se realizó un ensayo de aptitud para calibración de material volumétrico, con la participación de varios analistas (en su mayoría nuevos en la tarea) de los laboratorios de ensayo del Laboratorio Tecnológico del Uruguay (LATU). Para el mismo se utilizaron dos pipetas, una de vidrio de 1 ml y una pipeta automática de volumen regulable entre 0 y 1 ml, ésta última calibrada para el valor correspondiente a 1 ml. Con el fin de evaluar la repetibilidad en la medición, cada analista repitió entre 6 y 10 veces la calibración con cada pipeta. Se evaluó la media aritmética de las mediciones de cada analista para cada pipeta y se estimó su incertidumbre expandida. Aquí se presentan los gráficos con las medias y las incertidumbres obtenidas para cada tipo de pipeta y se efectúa un estudio comparativo de los resultados. A modo de conclusión se evaluó la reproducibilidad de cada tipo de instrumento, en base a lo cual se formulan recomendaciones para su uso y calibración. Abstract In 2008 several chemical analysts from LATU’s test laboratories (most of them new to their task) took part in a Proficiency Test for the use of volumetric glassware. Two pipettes were used: a glass pipette of 1 ml, class B, and an automatic pipette of variable volume between 0 ml and 1 ml. The latter was calibrated at 1 ml. All analysts were asked to repeat each calibration between 6 and 10 times to allow an estimate of the measurement repeatibility. The average value performed by each analyst for each pipette was evaluated and its uncertainty estimated. Graphs are presented showing the analysts’ means and uncertainties for each pipette and the results are compared. As a conclusion, the reproducibility of each kind of instrument is evaluated according to which recommendations are given for the calibration and use of the two types of pipette