Direct electroanalytical determination of fluvastatin in a pharmaceutical dosage form: batch and flow analysis

The reduction of luvastatin (FLV) at a hanging mercury-drop electrode (HMDE) was studied by square-wave adsorptive-stripping voltammetry (SWAdSV). FLV can be accumulated and reduced at the electrode, with a maximum peak current intensity at a potential of approximately 1.26V vs. AgCl=Ag, in an aqueous electrolyte solution of pH 5.25. The method shows linearity between peak current intensity and FLV concentration between 1.0 10 8 and 2.7 10 6 mol L 1. Limits of detection (LOD) and quantification (LOQ) were found to be 9.9 10 9 mol L 1 and 3.3 10 8 mol L 1, respectively. Furthermore, FLV oxidation at a glassy carbon electrode surface was used for its hydrodynamic monitoring by amperometric detection in a flow-injection system. The amperometric signal was linear with FLV concentration over the range 1.0 10 6 to 1.0 10 5 mol L 1, with an LOD of 2.4 10 7 mol L 1 and an LOQ of 8.0 10 7 mol L 1. A sample rate of 50 injections per hour was achieved. Both methods were validated and showed to be precise and accurate, being satisfactorily applied to the determination of FLV in a commercial pharmaceutical.

An Evaluation of Local Feature Combiners for Robot Visual Localization

In the last decade, local image features have been widely used in robot visual localization. To assess image similarity, a strategy exploiting these features compares raw descriptors extracted from the current image to those in the models of places. This paper addresses the ensuing step in this process, where a combining function must be used to aggregate results and assign each place a score. Casting the problem in the multiple classifier systems framework, we compare several candidate combiners with respect to their performance in the visual localization task. A deeper insight into the potential of the sum and product combiners is provided by testing two extensions of these algebraic rules: threshold and weighted modifications. In addition, a voting method, previously used in robot visual localization, is assessed. All combiners are tested on a visual localization task, carried out on a public dataset. It is experimentally demonstrated that the sum rule extensions globally achieve the best performance. The voting method, whilst competitive to the algebraic rules in their standard form, is shown to be outperformed by both their modified versions.

Housing conditions as a social determinant of low birthweight and preterm low birthweight

OBJECTIVE: To assess the relationship between housing conditions and low birthweight and preterm low birthweight among low-income women. METHODS: A case-control study was conducted with post-partum women living in the city of Rio de Janeiro, Southeast Brazil, in 2003-2005. Two groups of cases, low birthweight (n=96) and preterm low birthweight infants (n=68), were compared against normal weight term controls (n=393). Housing conditions were categorized into three levels: adequate, inadequate, and highly inadequate. Covariates included sociodemographic and anthropometric characteristics, risk behaviors, violence, anxiety, satisfaction during pregnancy, obstetric history and prenatal care. RESULTS: Poor housing conditions was independently associated with low birthweight (inadequate - OR 2.3 [1.1;4.6]; highly inadequate - OR 7.6 [2.1;27.6]) and preterm low birthweight (inadequate - OR 2.2 [1.1;4.3]; highly inadequate - OR 7.6 [2.4;23.9]) and factors associated with outcomes were inadequate prenatal care and previous preterm birth. Low income and low maternal body mass index remained associated with low birthweight. CONCLUSIONS: Poor housing conditions were associated with low birthweight and preterm low birthweight.

Chlormequat selective electrodes: construction, evaluation and application at FIA systems

A flow injection analysis (FIA) system having a chlormequat selective electrode is proposed. Several electrodes with poly(vinyl chloride) based membranes were constructed for this purpose. Comparative characterization suggestedthe use of membrane with chlormequat tetraphenylborate and dibutylphthalate. On a single-line FIA set-up, operating with 1x10-2 mol L-1 ionic strength and 6.3 pH, calibration curves presented slopes of 53.6±0.4mV decade-1 within 5.0x10-6 and1.0x10-3 mol L-1, andsquaredcorrelation coefficients >0.9953. The detection limit was 2.2x10-6 mol L-1 and the repeatability equal to ±0.68mV (0.7%). A dual-channel FIA manifold was therefore constructed, enabling automatic attainment of previous ionic strength andpH conditions and thus eliminating sample preparation steps. Slopes of 45.5±0.2mV decade -1 along a concentration range of 8.0x10-6 to 1.0x10-3 mol L-1 with a repeatability ±0.4mV (0.69%) were obtained. Analyses of real samples were performed, and recovery gave results ranging from 96.6 to 101.1%.

Electroanalytical study of the antidepressant sertraline

Aflowinjection squarewave cathodic stripping voltammetric method has been developed for the determination of sertraline in a pharmaceutical preparation. The method shows linearity between peak current intensity and sertraline concentration for the interval between 0.20×10−6 and 1.20×10−6 mol L−1. Limits of detection and quantification were found to be 1.5×10−7 and 5.0×10−7 mol L−1, respectively. Up to 70 samples per hour can be analysed with a good precision (R.S.D. = 2.5%). The proposed method was successfully applied to the determination of sertraline in a commercial product. In the voltammetric determination of sertraline in flow, a high sample rate is obtained at reduced costs, opening the possibility to compete with the chromatographic methods generally used for this analysis.

Analysis of PCBs in soils and sediments by microwave-assisted extraction, headspace-SPME and high resolution gas chromatography with ion-trap tandem mass spectrometry

A procedure for the determination of seven indicator PCBs in soils and sediments using microwave-assisted extraction (MAE) and headspace solid-phase microextraction (HS-SPME) prior to GC-MS/MS is described. Optimization of the HS-SPME was carried out for the most important parameters such as extraction time, sample volume and temperature. The adopted methodology has reduced consumption of organic solvents and analysis runtime. Under the optimized conditions, the method detection limit ranged from 0.6 to 1 ng/g when 5 g of sample was extracted, the precision on real samples ranged from 4 to 21% and the recovery from 69 to 104%. The proposed method, which included the analysis of a certified reference material in its validation procedure, can be extended to several other PCBs and used in the monitoring of soil or sediments for the presence of PCBs.

Survival of a cohort of women with cervical cancer diagnosed in a Brazilian cancer center

OBJECTIVE: To assess overall survival of women with cervical cancer and describe prognostic factors associated. METHODS: A total of 3,341 cases of invasive cervical cancer diagnosed at the Brazilian Cancer Institute, Rio de Janeiro, southeastern Brazil, between 1999 and 2004 were selected. Clinical and pathological characteristics and follow-up data were collected. There were performed a survival analysis using Kaplan-Meier curves and a multivariate analysis through Cox model. RESULTS: Of all cases analyzed, 68.3% had locally advanced disease at the time of diagnosis. The 5-year overall survival was 48%. After multivariate analysis, tumor staging at diagnosis was the single variable significantly associated with prognosis (p<0.001). There was seen a dose-response relationship between mortality and clinical staging, ranging from 27.8 to 749.6 per 1,000 cases-year in women stage I and IV, respectively. CONCLUSIONS: The study showed that early detection through prevention programs is crucial to increase cervical cancer survival.

Fatores associados à recidiva em hanseníase em Mato Grosso

OBJETIVO: Analisar fatores associados à ocorrência de recidiva em hanseníase. MÉTODOS: Estudo retrospectivo caso-controle com 159 pacientes maiores de 15 anos diagnosticados com hanseníase em cinco municípios do estado de Mato Grosso, cujas unidades de saúde eram consideradas de referência para o atendimento. O grupo de casos incluiu 53 indivíduos com recidiva de 2005 a 2007 e foi comparado ao grupo controle (106 com alta por cura em 2005), pareados por sexo e classificação operacional. Foram usados dados do Sistema de Informação de Agravos de Notificação, prontuários e entrevistas. Utilizou-se regressão logística condicional e abordagem hierárquica. RESULTADOS: Após análise ajustada, mostraram-se associados à ocorrência de recidiva: indivíduos residentes em casas alugadas (OR = 4,1; IC95%:1,43;12,04), em domicílio de madeira/taipa (OR = 3,2; IC95%: 1,16;8,76), que moravam com mais de cinco pessoas (OR = 2,1; IC95% : 1,03;4,36), com transtorno de uso de álcool (OR = 2,8; IC95%: 1,17;6,79), irregularidade do tratamento (OR = 3,8;IC95%: 1,44;10,02), sem esclarecimento sobre a doença/tratamento (OR = 2,6; IC95%: 1,09;6,13), que usavam transporte coletivo para o acesso à unidade de saúde (OR = 5,5; IC95%: 2,36;12,63), forma clínica da doença (OR = 7,1; IC95%: 2,48;20,52) e esquema terapêutico (OR = 3,7; IC95%: 1,49;9,11). CONCLUSÕES: Os fatores preditivos de recidiva relacionam-se com condições de moradia, hábitos de vida, organização dos serviços de saúde, formas clínicas e esquemas terapêuticos. Cabe aos serviços de saúde oferecer orientações adequadas aos pacientes, bem como garantir a regularidade do tratamento.

BabeLO : an extensible converter of programming exercises formats

In the last two decades, there was a proliferation of programming exercise formats that hinders interoperability in automatic assessment. In the lack of a widely accepted standard, a pragmatic solution is to convert content among the existing formats. BabeLO is a programming exercise converter providing services to a network of heterogeneous e-learning systems such as contest management systems, programming exercise authoring tools, evaluation engines and repositories of learning objects. Its main feature is the use of a pivotal format to achieve greater extensibility. This approach simplifies the extension to other formats, just requiring the conversion to and from the pivotal format. This paper starts with an analysis of programming exercise formats representative of the existing diversity. This analysis sets the context for the proposed approach to exercise conversion and to the description of the pivotal data format. The abstract service definition is the basis for the design of BabeLO, its components and web service interface. This paper includes a report on the use of BabeLO in two concrete scenarios: to relocate exercises to a different repository, and to use an evaluation engine in a network of heterogeneous systems.

Asociación entre ver televisión y obesidad en mujeres peruanas

OBJETIVO: Evaluar la asociación entre frecuencia de ver televisión, sobrepeso y obesidad en una muestra representativa de mujeres peruanas a nivel nacional. MÉTODOS: Análisis secundario de la Encuesta Nacional Demográfica y de Salud Familiar incluyendo mujeres de 15 a 49 años. Las variables resultados fueron obesidad (índice de masa corporal >30 kg/m²) y sobrepeso (>25 peso <30 kg/m²); mientras que la exposición fue la frecuencia de ver televisión (nunca, ocasionalmente, casi todos los días). Se usó regresión logística para análisis de muestras complejas según el diseño de la encuesta ajustando por potenciales confusores. Los resultados fueron presentados como Odds Ratio ajustados (ORa) con sus respectivos intervalos de confianza al 95% (IC95%). RESULTADOS: Un total de 21.712 mujeres fueron incluidas en el análisis. La prevalencia de sobrepeso fue 34,7% (IC95% 33,8;35,7) y de obesidad fue 14,3% (IC95% 13,6;15,1). Las mujeres que veían televisión ocasionalmente y casi todos los días tuvieron mayor probabilidad de tener obesidad: ORa 1,7 (IC95% 1,3;2,3) y ORa 2,6 (IC95% 2,0;3,5), respectivamente comparado con aquellas que nunca veían televisión. La magnitud de la asociación fue menor para el caso de sobrepeso: ORa 1,2 (IC95% 1,3;2,3) y ORa 1,6 (IC95% 1,1;1,4), respectivamente. La fuerza de la asociación fue mayor en el área urbana. CONCLUSIONES: En mujeres peruanas la frecuencia de ver televisión estuvo asociada con presentar obesidad y sobrepeso, y la fuerza de asociación varió de acuerdo al área de residencia. Estos hallazgos deberían orientar las estrategias de prevención de la obesidad en el contexto peruano.

Electrochemical determination of the herbicide bentazone using a carbon nanotube b-Cyclodextrin modified electrode

An electrochemical sensor has been developed for the determination of the herbicide bentazone, based on a GC electrode modified by a combination of multiwalled carbon nanotubes (MWCNT) with b-cyclodextrin (b-CD) incorporated in a polyaniline film. The results indicate that the b-CD/MWCNT modified GC electrode exhibits efficient electrocatalytic oxidation of bentazone with high sensitivity and stability. A cyclic voltammetric method to determine bentazone in phosphate buffer solution at pH 6.0, was developed, without any previous extraction, clean-up, or derivatization steps, in the range of 10–80 mmolL 1, with a detection limit of 1.6 mmolL 1 in water. The results were compared with those obtained by an established HPLC technique. No statistically significant differences being found between both methods.

Desigualdades sociais e tuberculose: análise segundo raça/cor, Mato Grosso do Sul

OBJETIVO Analisar características sociodemográficas e clínico-epidemiológicas dos casos de tuberculose e fatores associados ao abandono e ao óbito na vigência do tratamento. MÉTODOS Estudo epidemiológico baseado em dados notificados de tuberculose em indígenas e não indígenas, segundo raça/cor, em Mato Grosso do Sul, entre 2001 e 2009. Realizou-se análise descritiva dos casos de acordo com as variáveis sexo, faixa etária, zona de residência, exames empregados para o diagnóstico, forma clínica, tratamento supervisionado e situação de encerramento, segundo raça/cor. Utilizou-se análise univariada e múltipla por meio de regressão logística para identificar preditores de abandono e óbito, e odds ratio como medida de associação. Foi construída série histórica de incidência, segundo raça/cor. RESULTADOS Registraram-se 6.962 casos novos de tuberculose no período, 15,6% entre indígenas. Houve predomínio em homens e adultos (20 a 44 anos) em todos os grupos. A maior parte dos doentes indígenas residia na zona rural (79,8%) e 13,5% dos registros nos indígenas ocorreram em < 10 anos. A incidência média no estado foi 34,5/100.000 habitantes, 209,0; 73,1; 52,7; 23,0 e 22,4 entre indígenas, amarelos, pretos, brancos e pardos, respectivamente. Doentes de 20 a 44 anos (OR = 13,3; IC95% 1,9;96,8), do sexo masculino (OR = 1,6; IC95% 1,1;2,3) e de raça/cor preta (OR = 2,5; IC95% 1,0;6,3) mostraram associação com abandono de tratamento, enquanto doentes > 45 anos (OR = 3,0; IC95% 1,2;7,8) e com a forma mista (OR = 2,3; IC95% 1,1;5,0) apresentaram associação com óbito. Apesar de representarem 3,0% da população, os indígenas foram responsáveis por 15,6% das notificações no período. CONCLUSÕES Houve importantes desigualdades em relação ao adoecimento por tuberculose entre as categorias estudadas. As incidências nos indígenas foram consistentemente maiores, chegando a exceder em mais de seis vezes as médias nacionais. Entre pretos e pardos, piores resultados no tratamento foram observados, pois apresentaram chance de abandono duas vezes maior que os indígenas. O mau desempenho do programa também esteve fortemente associado ao abandono e ao óbito. Acredita-se que, enquanto não se reduzir a pobreza, as desigualdades nos indicadores em saúde permanecerão.

Seroprevalencia de rubeola en Colombia: un análisis por cohorte de nacimiento

OBJETIVO : Estimar la seroprevalencia de rubéola y factores asociados. METODOS : Estudio de seroprevalencia poblacional con una muestra aleatoria de 2.124 individuos de seis a 64 años, representativa por edad, sexo y área en Medellín, Colombia, 2009. Se analizó la asociación de variables biológicas y socioeconómicas con la seroprotección para rubéola, según la cohorte del año de nacimiento antes (1954 a 1990) y después (1991 a 2003) del inicio de la vacunación universal. Se determinaron los títulos de IgG con pruebas de alta sensibilidad (AxSYM ® Rubella IgG – Laboratorio Abbott) y especificidad (VIDAS RUB IgG II ® – Laboratorio BioMerieux). Se estimaron proporciones y promedios ponderados derivados de un muestreo complejo incluyendo un factor de corrección por las diferencias en la participación por sexo. Se analizó la asociación de la protección por grupos de variables biológicas y sociales con un modelo de regresión logística, según la cohorte de nacimiento. RESULTADOS : Los títulos promedio de IgG fueron más altos en los nacidos antes del inicio de la vacunación (media 110 UI/ml; IC95% 100,5;120,2) que en los nacidos después (media 64 UI/ml; IC95% 54,4;72,8), p = 0,000. La proporción de protección fue creciente de 88,9% en los nacidos en 1990-1994, de 89,2% en 1995-1999 y de 92,1% en 2000 a 2003, posiblemente relacionado con la administración del refuerzo desde 1998. En los nacidos antes del inicio de la vacunación, la seroprotección estuvo asociada con el antecedente de contacto con casos (RD 2,6; IC95% 1,1;5,9), el estado de salud (RD 2,5; IC95% 1,05;6,0), el nivel de escolaridad (RD 0,2; IC95% 0,08;0,8) y los años de residencia del hogar en el barrio (RD 0,96; IC95% 0,98;1,0), luego de ajustar por todas las variables. En los nacidos después se asoció con el tiempo de sueño efectivo (RD 1,4; IC95%1,09;1,8) y el estado de salud (RD 5,5; IC95%1,2;23,8). CONCLUSIONES : La vacunación masiva generó un cambio en el perfil de seroprevalencia, siendo mayores los títulos en quienes nacieron antes del inicio de la vacunación. Se recomienda monitorear el sostenimiento del nivel de protección a largo plazo y concertar acciones para el mejoramiento de las condiciones socioeconómicas potencialmente asociadas.

Uncertainty propagation in inverse reliability-based design of composite structures

An approach for the analysis of uncertainty propagation in reliability-based design optimization of composite laminate structures is presented. Using the Uniform Design Method (UDM), a set of design points is generated over a domain centered on the mean reference values of the random variables. A methodology based on inverse optimal design of composite structures to achieve a specified reliability level is proposed, and the corresponding maximum load is outlined as a function of ply angle. Using the generated UDM design points as input/output patterns, an Artificial Neural Network (ANN) is developed based on an evolutionary learning process. Then, a Monte Carlo simulation using ANN development is performed to simulate the behavior of the critical Tsai number, structural reliability index, and their relative sensitivities as a function of the ply angle of laminates. The results are generated for uniformly distributed random variables on a domain centered on mean values. The statistical analysis of the results enables the study of the variability of the reliability index and its sensitivity relative to the ply angle. Numerical examples showing the utility of the approach for robust design of angle-ply laminates are presented.

Intermodulation in active reconfigurable antennas

Due to the application of active components into antennas these became a source of distortion on wireless communication systems. In this paper we explore the nonlinear effects occurring in a frequency reconfigurable antenna operating with a PIN Diode. We describe the measurement setup used to check the antenna intermodulation products and the measured compression and third order intermodulation limitations of a frequency reconfigurable antenna, operating at the UMTS and WLAN frequencies.