The Stability and Properties of Polystyrene/Kaolinite Nanocomposites during Synthesis via Emulsion Polymerization.

The aim of this work was to study the stability and morphological properties of polystyrene latex containing kaolinite as a filler during the process of synthesis of nanocomposites viaemulsion polymerization. Nanocomposites with 1, 3, and 5 wt% of kaolinite were prepared. Latexes with 1 to 3 wt% of kaolinite were stable during the polymerization reaction. Hydrodynamic diameters of 93.68 and 82.11 nm were found for latexes with 1 and 3 wt% of kaolinite, respectively. The quantities of 1 to 3 wt% of kaolinite added during the reaction did not influence the reaction conversion curves or the number of particles. X-ray diffraction (XRD) and unconventional techniques of scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) showed the presence of exfoliated and intercalated structures of the kaolinite.

Resolving the taxonomic puzzle of Boana cinerascens (Spix, 1824), with resurrection of Hyla granosa gracilis Melin, 1941 (Anura: Hylidae).

Expeditions to unexplored or little explored places are important for discovering new species and also for collecting new samples (including specimens and tissues for DNA sequencing ) that may help resolve a plethora of taxonomic problems. In the 19th century, several naturalists explored a number of localities in Amazonia, describing species for which type material was deposited, mostly, in European museums of natural history. Some of these types were lost or destroyed in World War II and recent expeditions have focused on sampling new material from the type localities. material from Boana cinerascens, which allowed us to infer phylogenetic relationships of the Boana punctata group (i.e., green Boana), based on DNA sequence data, and to revaluate the status of B. cinerascens and its synonyms. We designate, redescribe and illustrate a neotype for B. cinerascens, which was described by Spix in 1824, from the Municipality of Tefé, State of Amazonas, Brazil. We revalidate, redescribe, and illustrate Hyla granosa gracilis Melin, 1941(= Boana gracilis). Corroborating previous studies, the green Boana were not recovered as a monophyletic group. Boana cinerascens is sister of B. gracilis plus a clade containing B. atlantica + B. punctata (both species not recovered as monophyletic).

A new species of Phyzelaphryne Heyer, 1977 (Anura: Eleutherodactylidae) from the Japurá River basin, with a discussion of the diversity and distribution of the genus.

We describe and name the second species of Phyzelaphryne (Brachycephaloidea, Eleutherodactylidae), from northwestern Brazilian Amazonia. Phyzelaphryne nimio sp. nov. is distinguished from its only congener, Phyzelaphryne miriamae, by its smaller body size and the anatomy of the carpal and metacarpal regions, with relatively larger (sometimes fused) supernumerary carpal and metacarpal tubercles. Molecular phylogenetic analyses based on fragments of the mitochondrial genes 16S rRNA and COI suggest that the currently known distribution of the species is restricted to its type locality and other areas within Estação Ecológica Juami-Japurá, state of Amazonas, Brazil. Based on molecular, morphological and bioacoustic evidence, we assigned other specimens recently collected in Parque Nacional do Jaú, state of Amazonas, Brazil, to P. miriamae, extending the species' known geographic distribution north of the Amazon River.

Multimodality imaging of a huge subaortic left ventricular aneurysm in a child.

A subannular left ventricular aneurysm is very rare, and is mostly considered to be a congenital anomaly. A subannular left ventricular aneurysm is classified based on the type of its own orifice-submitral or subaortic. Subaortic left ventricular aneurysm occurs less frequently compared with a submitral type of subannular aneurysm. We hereby describe a rare case of a huge bilobed subaortic aneurysm, in which the orifice was located just below the left coronary cusp diagnosed with multimodality imaging in a child.

Submitral aneurysm and the new imaging modalities: Will magnetic resonance imaging be necessary?

Submitral aneurysm is a rare cardiac malformation commonly reported in young adult African ancestry. Transthoracic echocardiogram is a gold standard test for diagnosis. Magnetic resonance imaging provides detailed anatomic and functional information of the heart. We present a case of a large bilobed submitral aneurysm in-witch the magnetic resonance imaging confirmed the same findings of the transthoracic echocardiography and in addiction also showed a parietal thrombus.

The real identity of Leptodiranycthemera Werner, 1901 from Ecuador: a junior synonym of Oxyrhopuspetolarius (Linnaeus, 1758) (Serpentes, Dipsadidae).

Leptodiranycthemera Werner, 1901, was described from a specimen collected in Ecuador. No information on the holotype was published after its description. In the most recent review of Leptodeira, Leptodiranycthemera was considered to be a synonym of Leptodeiraannulataannulata, although the author emphasized that the holotype was lost and did not include the pholidotic data from the original description in his account of Leptodeiraannulataannulata. Since this review, a number of authors have accepted this synonymy. Recently, analyzing specimens of Leptodeira in the Museum für Naturkunde, Berlin, Germany, we discovered the holotype of Leptodiranycthemera. This holotype is re-described here, and its correct identity is determined. Based on the analysis of meristic characters and the color of the holotype, we recognize Leptodiranycthemera as a junior synonym of Oxyrhopuspetolarius.

Validation in principal components analysis applied to EEG data.

The well-known multivariate technique Principal Components Analysis (PCA) is usually applied to a sample, and so component scores are subjected to sampling variability. However, few studies address their stability, an important topic when the sample size is small. This work presents three validation procedures applied to PCA, based on confidence regions generated by a variant of a nonparametric bootstrap called the partial bootstrap: (i) the assessment of PC scores variability by the spread and overlapping of "confidence regions" plotted around these scores; (ii) the use of the confidence regions centroids as a validation set; and (iii) the definition of the number of nontrivial axes to be retained for analysis. The methods were applied to EEG data collected during a postural control protocol with twenty-four volunteers. Two axes were retained for analysis, with 91.6% of explained variance. Results showed that the area of the confidence regions provided useful insights on the variability of scores and suggested that some subjects were not distinguishable from others, which was not evident from the principal planes. In addition, potential outliers, initially suggested by an analysis of the first principal plane, could not be confirmed by the confidence regions.

[Correspondence analysis: a theoretical basis for categorical data interpretation in health sciences]. / Análise de Correspondência: bases teóricas na interpretação de dados categóricos em Ciências da Saúde.

Categorical variables are common in the biomedical field, and many descriptive methods have been proposed for revealing intrinsic patterns in data. Correspondence Analysis is an especially useful method for categorical data analysis of large contingency tables. Although numerous studies have been published on this method, most Portuguese-language articles have failed to explore its full potential, focusing only on graphical interpretation. The current paper reviews the method, showing that graphical analysis can be enriched by the right statistics. The article presents the mathematical basis for correspondence analysis and its most frequently used statistics. The procedure has shown that such statistics enrich symmetric map evaluation, that a low relative frequency category can be represented by supplementary category points, and that inertia contributions are highly related to residual analysis of contingency tables, not easily visualized by symmetric maps. Correspondence Analysis has proven advantageous when compared to principal components analysis.

Increase in biofilm formation by Escherichia coli under conditions that mimic the mastitic mammary gland / Aumento na formação de biofilmes por Escherichia coli em condições que mimetizam a glândula mamária mastítica

Bacterial biofilms are involved in the aggravation and recurrence of clinical mastitis in dairy herds. Several factors such as pH, temperature, concentration of O2 and glucose can affect their induction and growth rates. In this study, biofilm production was demonstrated by 27 Escherichia coli strains isolated from bovine mastitis at different pH values depending on the availability of glucose, mimicking conditions found in mammary glands affected by the disease. Biofilm formation was analyzed by spectrophotometric analysis in microtiter plate with 16 different culture media and by scanning electron microscopy. Biofilm formation was greater in isolates cultured under conditions associated with low glucose availability (0.5% or 1.5%) and with either an acidic (5.5) or alkaline (8.5) pH, compared to conditions associated with high glucose availability (2.5% or 3.5%) and near-neutral pH (6.5 or 7.5). Results indicate possible favoring of biofilm production in the later stages of the infectious process caused by E. coli, when the gland environment is less propitious to bacterial growth due to the stress conditions mentioned above; contrasting with the environment of the healthy mammary gland, in which there is no limitation on nutrients or conditions of particular alkalinity or acidity. Thus, knowledge of the stage in which is the infection and environmental conditions of the mammary gland that cause increased production of biofilms is of paramount importance to guide the most appropriate control strategies to prevent relapse after treatment of bovine mastitis, an economically important disease in dairy cattle worldwide.

Biofilmes bacterianos estão envolvidos no agravamento e recorrência de mastite clínica em rebanhos leiteiros. Vários fatores, tais como o pH, temperatura, concentração de O2 e glicose podem afetar sua indução e suas taxas de crescimento. Neste estudo, a produção de biofilme foi demonstrada por 27 isolados de Escherichia coli de mastite bovina a valores de pH diferentes, dependendo da disponibilidade de glucose, simulando as condições encontradas nas glândulas mamárias afetadas pela doença. A formação de biofilme foi analisada por espectrofotometria em microplaca com 16 diferentes meios de cultura e por microscopia eletrônica de varredura. A formação de biofilmes foi maior em isolados cultivados em condições associadas com baixa disponibilidade de glucose (0,5% ou 1,5%) tanto com pH ácido (5,5) como alcalino (8,5), em comparação com as condições associadas com a disponibilidade de alto teor de glucose (2,5% ou 3,5% ) e pH próximo à neutralidade (6,5 ou 7,5). Os resultados indicam o possível favorecimento da produção de biofilmes em fases posteriores do processo infeccioso de mastite causada por E. coli, quando o ambiente da glândula é menos propício ao crescimento bacteriano devido às condições de estresse acima mencionados, em contraste com o ambiente da glândula mamária saudável, no qual não há nenhuma limitação de nutrientes ou condições de alcalinidade ou acidez em particular. Ainda, o conhecimento da fase em que se encontra a infecção e as condições ambientais da glândula que causariam maior produção de biofilmes é de grande importância para orientar as estratégias de controle mais adequadas para prevenir recidivas após o tratamento da mastite bovina, uma doença economicamente importante na bovinocultura leiteira em todo o mundo.

Análise de Correspondência: bases teóricas na interpretação de dados categóricos em Ciências da Saúde / Correspondence Analysis: a theoretical basis for categorical data interpretation in Health Sciences / Análisis de Correspondencia: bases teóricas para la interpretación de datos categóricos en Ciencias de Salud

Na área biomédica, a ocorrência de dados categóricos é comum, e métodos de análise específicos para este tipo de dado são usados para revelar padrões existentes. A Análise de Correspondência é uma dessas técnicas, utilizada na análise de tabelas de contingência de grande porte. A maioria dos trabalhos publicados em periódicos brasileiros foca apenas na sua interpretação gráfica, não abordando outras potencialidades da técnica. O objetivo do trabalho é mostrar a técnica não limitada à análise gráfica, mas também utilizar estatísticas que permitem sua análise quantitativa. Exemplo mostra que a análise gráfica é enriquecida com a utilização dessas estatísticas, e que a inclusão de uma categoria com baixa ocorrência pode ser considerada como categoria suplementar devido à sua baixa contribuição à inércia. Assim, diminui-se a subjetividade na análise, sendo possível revelar a relação entre as categorias com a análise de resíduos, aspecto este não facilmente observado graficamente. Comparação com a Análise de Componentes Principais mostrou a vantagem da técnica.

Categorical variables are common in the biomedical field, and many descriptive methods have been proposed for revealing intrinsic patterns in data. Correspondence Analysis is an especially useful method for categorical data analysis of large contingency tables. Although numerous studies have been published on this method, most Portuguese-language articles have failed to explore its full potential, focusing only on graphical interpretation. The current paper reviews the method, showing that graphical analysis can be enriched by the right statistics. The article presents the mathematical basis for correspondence analysis and its most frequently used statistics. The procedure has shown that such statistics enrich symmetric map evaluation, that a low relative frequency category can be represented by supplementary category points, and that inertia contributions are highly related to residual analysis of contingency tables, not easily visualized by symmetric maps. Correspondence Analysis has proven advantageous when compared to principal components analysis.

En el campo biomédico, los datos categóricos son frecuentemente utilizados y los métodos de análisis específicos son empleados para revelar patrones intrínsecamente existentes en los mismos. El Análisis de Correspondencias es una de estas técnicas, siendo útil en el análisis de tablas de contingencia con un gran número de clases. A pesar de que muchos artículos han explorado esta técnica, la mayoría de trabajos en revistas brasileñas se centra sólo en su interpretación gráfica. El objetivo de este trabajo es incluir estadísticas que permitan la interpretación cuantitativa de la técnica. Como ejemplo, tenemos el análisis de un mapa simétrico enriquecido con el uso de estadísticas, en el cual la inclusión de una clase de baja ocurrencia puede ser considerada como una categoría suplementaria, debido a su baja contribución a la inercia de datos. Por lo tanto, disminuye la subjetividad en el análisis, siendo posible ahora revelar la relación entre las categorías con el análisis residual, lo que no es fácil observar en los gráficos. La comparación con el análisis de componentes principales mostró sus ventajas.

Increased production of biofilms by Escherichia coli in the presence of enrofloxacin.

The literature has demonstrated that subinhibitory concentrations of some antimicrobials are able to induce biofilm formation by certain bacterial species. Biofilms present in the mammary glands of cattle contribute to antimicrobial resistance, resulting in the appearance of persistent mastitis and consequent great losses to the dairy sector worldwide. The present study aimed to investigate the induction of biofilm formation by enrofloxacin in Escherichia coli isolates obtained from bovine mastitis. Twenty-seven isolates were reactivated in brain heart infusion (BHI) broth supplemented with different subinhibitory concentrations of enrofloxacin. Biofilm formation in microtiter plates was measured and confirmed by scanning electron microscopy (SEM). Isolates submitted to the concentration 0.0125 mg/mL of enrofloxacin showed greater biofilm formation compared to the control (p<0.001). Biofilm formation results obtained for the other concentrations did not differ from those obtained for the control (p>0.05). Using SEM it was possible to visualize the typical architecture of biofilms. These results represent the first report of inducing the production of biofilms in the presence of enrofloxacin, a quinolone antibiotic used to treat clinical mastitis.

Reptiles from Lençóis Maranhenses National Park, Maranhão, northeastern Brazil.

We are presenting a list of the reptile species from Lençóis Maranhenses National Park (LMNP), Maranhão, Brazil, obtained during 235 days of field work. The study area is located in the contact zone between three major Neotropical ecosystems: Amazonia, Caatinga, and Cerrado. The PNLM encompasses the largest dune fields in Brazil, wide shrubby areas (restingas), lakes, mangroves, and many freshwater lagoons. We have recorded 42 species of reptiles in the area: 24 snakes, 12 lizards, two worm lizards, three turtles, and one alligator. About 81 % of the recorded species occurred only in restinga areas. Our data highlights the uniqueness of the PNLM in the context of the biomes that surround it and shows the importance of efforts to improve the conservation of reptiles living in the restinga, which currently comprise only about 20 % of the total area protected by the park, but which are the mesohabitat containing most of the reptile species in the Lençóis Maranhenses complex of habitats.

Iron Oxide Silica Derived from Sol-Gel Synthesis.

In this work we investigate the effect of iron oxide embedded in silica matrices as a function of Fe/Si molar ratio and sol pH. To achieve homogeneous dispersion of iron oxide particles, iron nitrate nonahydrate was dissolved in hydrogen peroxide and was mixed with tetraethyl orthosilicate and ethanol in a sol-gel synthesis method. Increasing the calcination temperature led to a reduction in surface area, although the average pore radius remained almost constant at about 10 Å, independent of the Fe/Si molar ratio or sol pH. Hence, the densification of the matrix was accompanied by similar reduction in pore volume. However, calcination at 700 °C resulted in samples with similar surface area though the iron oxide content increased from 5% to 50% Fe/Si molar ratio. As metal oxide particles have lower surface area than polymeric silica structures, these results strongly suggest that the iron oxides opposed the silica structure collapse. The effect of sol pH was found to be less significant than the Fe/Si molar ratio in the formation of molecular sieve structures derived from iron oxide silica.

Multiple correspondence analysis in predictive logistic modelling: application to a living-donor kidney transplantation data.

This work deals with the use of multiple correspondence analysis (MCA) and a weighted Euclidean distance (the tolerance distance) as an exploratory tool in developing predictive logistic models. The method was applied to a living-donor kidney transplant data set with 109 cases and 13 predictors. This approach, followed by backward and forward selection procedures, yielded two models, one with four and another with two predictors. These models were compared to two other models, ordinarily built by backward and forward stepwise selection, which yielded, respectively, five and two predictors. After internal validation, the models performance statistics showed similar results. Likelihood ratio tests suggested that backward approach achieved a better fit than the forward modelling in both methods and the Vuong's non-nested test between backward-built models suggested that these were undistinguishable. We conclude that the tolerance distance, in combination with MCA, could be a feasible method for variable selection in logistic modelling, when there are several categorical predictors.

A heuristic index for selecting similar categories in multiple correspondence analysis applied to living donor kidney transplantation.

This work introduces a heuristic index (the "tolerance distance") to define the "closeness" of two variable categories in multiple correspondence analysis (MCA). This index is a weighted Euclidean distance where weightings are based on the "importance" of each MCA axis, and variable categories were considered to be associated when their distances were below the tolerance distance. This approach was applied to a renal transplantation data. The analysed variables were allograft survival and 13 of its putative predictors. A bootstrap-based stability analysis was employed for assessing result reliability. The method identified previously detected associations within the database, such as that between race of donors and recipients, and that between HLA match and Cyclosporine use. A hierarchical clustering algorithm was also applied to the same data, allowing for interpretations similar to those based on MCA. The defined tolerance distance could thus be used as an index of "closeness" in MCA, hence decreasing the subjectivity of interpreting MCA results.

[Prevention of occupational accidents with biological material as per Green and Kreuter Model]. / Prevenção de acidentes de trabalho com material biológico segundo o modelo de Green e Kreuter.

This study aimed at diagnosing the occurrence of occupational accidents deriving from exposition to biological substance among workers of a hospital from São Paulo, Brazil, analyzing the adopted safety measures and elaborating a flowchart of preventive actions according to the Health Promotion Model by Green and Kreuter. It is an exploratory study with data collected electronically from the website REPAT - Electronic Network for the Prevention of Occupational Accidents with biological substances. The strategy used by the hospital did not reduce the injures. Results were used to elaborate a flowchart of preventive actions in order to improve the workers' quality of life.

Prevenção de acidentes de trabalho com material biológico segundo o modelo de Green e Kreuter / Prevention of occupational accidents with biological material as per Green and Kreuter Model

Os objetivos do estudo foram diagnosticar a ocorrência de acidentes de trabalho decorrentes de exposição a material biológico entre trabalhadores de um hospital de São Paulo, Brasil, levantar as medidas de prevenção adotadas e elaborar fluxograma de ações preventivas estruturado no Modelo de Promoção à Saúde de Green e Kreuter. Estudo exploratório com dados coletados eletronicamente por meio do portal da Rede Eletrônica de Prevenção a Acidentes de Trabalho com material biológico (REPAT). A estratégia usada no hospital não reduziu as injúrias. Os resultados obtidos subsidiaram a elaboração de um fluxograma de ações preventivas para melhorar a qualidade de vida dos trabalhadores