Competitive adsorption of wellbores corrosion inhibitor onto steel, esmectite and sandstone

A commercial corrosion inhibitor used in petroleum production was characterized by means of infrared spectroscopy and energy dispersive spectroscopy (EDS). Predicting the adsorption behavior of corrosion inhibitor onto steel, sandstone and esmectite is the key to improve working conditions. In this study, the adsorption kinetics of inhibitor formulations in HCl 15% or in Mud Acid (HCl 13,5% and ammonium bifluoride) onto steel, sandstone and esmectite was determined by means of spectrophotometry. Kinetic parameters indicated that adsorption of inhibitor in the presence of bifluoride was favored. Moreover, the adsorption constant rate was the largest when the substrate was esmectite.FAPESPCNP

Modeling the quantum evolution of the universe through classical matter

It is well known that the canonical quantization of the Friedmann-Lema\^itre-Robertson-Walker (FLRW) filled with a perfect fluid leads to nonsingular universes which, for later times, behave as their classical counterpart. This means that the expectation value of the scale factor $(t)$ never vanishes and, as $t\to\infty$, we recover the classical expression for the scale factor. In this paper, we show that such universes can be reproduced by classical cosmology given that the universe is filled with an exotic matter. In the case of a perfect fluid, we find an implicit equation of state (EoS). We then show that this single fluid with an implict EoS is equivalent to two non-interacting fluids, one of them representing stiff matter with negative energy density. In the case of two non-interacting scalar fields, one of them of the phantom type, we find their potential energy. In both cases we find that quantum mechanics changes completely the configuration of matter for small values of time, by adding a fluid or a scalar field with negative energy density. As time passes, the density of negative energy decreases and we recover the ordinary content of the classical universe. The more the initial wave function of the universe is concentrated around the classical big bang singularity, the more it is necessary to add negative energy, since this type of energy will be responsible for the removal of the classical singularity.Comment: updated version as accepted by Gen. Relativ. Gravi

Biotechnological applications of selected macroalgae

IBBA Strategic Planning - Workshop III, Plant Biotechnology Ponta Delgada, 25 Janeiro, 2011

Effects of in situ shading on the photophysiology of Zostera marina and Cymodocea nodosa

The effects of light reduction were investigated in natural stands of the seagrasses Zostera marina and Cymodocea nodosa in Ria Formosa coastal lagoon, southern Portugal. Four shading plots and a control were set in each of two neighbouring meadows (2-3 m depth), each dominated by one species. The experiment lasted for 3 weeks, at the end of which the response of plant photosynthesis to light was determined via oxygen electrode measurements. Tissue samples were also analysed for photosynthetic pigment, soluble protein, soluble sugar and malondialdehyde contents. All plants presented a shade-adapted profile, mostly revealed by their biochemical composition. In both species the chlorophyll a/chlorophyll b ratio decreased sharply whereas the total chlorophyll/total carotenoids and the total chlorophyll/soluble protein ratios increased. Soluble protein content was reduced more noticeably in Z. marina. Soluble sugars dropped almost 40% in Z. marina leaves and roots, a more pronounced effect than the one observed in C. nodosa. Overall, Z. marina revealed to be more sensitive than C. nodosa to reductions in incident irradiance, suggesting that it will be more sensitive to human-induced disturbances that result in an increase of water turbidity

Nature through the eyes of chemistry: characterization of novel active molecules from Azorean Natural Products

Jornadas "Ciência nos Açores – que futuro?", Ponta Delgada, 7-8 de Junho de 2013.A área de Química de Produtos Naturais tem contribuído, grandemente, para a descoberta de fármacos e agroquímicos, entre outros, por meio do isolamento de substâncias ativas produzidas por diversos organismos. As novas moléculas têm grande interesse científico, económico, social e farmacológico podendo contribuir, em muito, para a saúde das pessoas e para a sua qualidade de vida. O rastreio de novos compostos com atividade biológica tem sido, recentemente, uma das prioridades da comunidade científica e os Açores, pelas suas características particulares e endemismos assumem particular importância nesta área de investigação. O estudo das potencialidades de plantas e organismos marinhos dos Açores tem sido desenvolvido na Universidade dos Açores/CIRN desde a década de noventa, usando a estratégia de investigação seguinte: (i) seleção dos organismos mais promissores para fins industriais e comerciais pela avaliação da sua atividade em ensaios biológicos diversos, (ii) extração, separação e identificação dos compostos bioativos e (iii) estudos da relação estrutura-atividade dos compostos bioativos isolados.ABSTRACT: The chemistry of Natural Products has contributed greatly to the discovery of pharmaceuticals and agrochemicals agents, among others, by the isolation of active substances produced by various organisms. The new molecules are of great scientific, economic, social and pharmacological importance and may contribute greatly to the people's health and their quality of life. The screening for new compounds with biological activity has been a recent priority for the scientific community and the Azores, by its particular characteristics and endemism is of crucial importance in this area of research. The study of the Azorean plants and marine organisms potential has been investigated in Azores University/CIRN since the '90s decade, using the following research strategy: (i) screening of the most promising organisms for industrial and commercial purposes by evaluating their activity in several biological assays, (ii) extraction, purification and molecular structure elucidation of the bioactive compounds, and (iii) studies of structure-activity relationships of the isolated bioactive compounds

Behavioral phenotype of children and adolescents with Prader-Willi syndrome

OBJETIVO: Identificar, em um grupo de crianças e adolescentes com síndrome de Prader-Willi, as principais características do fenótipo comportamental. MÉTODOS: A amostra foi composta por 11 crianças e adolescentes com diagnóstico clínico e citogenético-molecular da síndrome de Prader-Willi. A técnica de coleta de dados foi o Inventário dos Comportamentos de Crianças e Adolescentes entre 6 e 18 anos (CBCL/6-18). A análise de correlação bivariada, com nível de significância p<0,05, foi usada para testar a associação entre as variáveis analisadas. RESULTADOS: Os principais resultados mostraram um perfil comportamental considerado como clínico em várias das escalas do CBCL/6-18. Observou-se um padrão comportamental com alta frequência de respostas de agressão, quebra de regras e oposição. Identificaram-se correlações estatisticamente significativas entre problemas de atenção e sociais e problemas de pensamento e comportamento de quebrar as regras. CONCLUSÕES: Os pacientes investigados representam um grupo com risco psiquiátrico e alterações de comportamento que, em longo prazo, poderão evoluir para transtornos de 2009humor, do déficit de atenção e hiperatividade e transtorno desafiador e de oposição, dentre outrosOBJECTIVE: To identify the main characteristics of the behavioral phenotype of children and adolescents with Prader-Willi syndrome. METHODS: Eleven children and adolescents with clinical and cytogenetic-molecular diagnosis of Prader-Willi syndrome were studied. Data collection was obtained by the Child Behavior Checklist for Ages 6-18 (CBCL/6-18). Bivariate correlations were used to test the association between the analyzed variables, being significant p<0.05. RESULTS: The behavioral profile obtained was considered as clinical in different scales of the CBCL/6-18 tool. A behavioral pattern with high frequency of aggression, rule breaking and opposition was observed. Statistically significant correlations between attention and social problems and between thought problems and breaking rules were identified. CONCLUSIONS: The studied patients represent a group of psychiatric risk, with behavioral changes that, in the long-term, can lead to mood disorders, attention deficit hyperactivity disorder and oppositional defiant behavior, among other disordersInstituto Presbiteriano Mackenzie - MackPesquis

Automatic 3D pulmonary nodule detection in CT images: a survey

This work presents a systematic review of techniques for the 3D automatic detection of pulmonary nodules in computerized-tomography (CT) images. Its main goals are to analyze the latest technology being used for the development of computational diagnostic tools to assist in the acquisition, storage and, mainly, processing and analysis of the biomedical data. Also, this work identifies the progress made, so far, evaluates the challenges to be overcome and provides an analysis of future prospects. As far as the authors know, this is the first time that a review is devoted exclusively to automated 3D techniques for the detection of pulmonary nodules from lung CT images, which makes this work of noteworthy value. The research covered the published works in the Web of Science, PubMed, Science Direct and IEEEXplore up to December 2014. Each work found that referred to automated 3D segmentation of the lungs was individually analyzed to identify its objective, methodology and results. Based on the analysis of the selected works, several studies were seen to be useful for the construction of medical diagnostic aid tools. However, there are certain aspects that still require attention such as increasing algorithm sensitivity, reducing the number of false positives, improving and optimizing the algorithm detection of different kinds of nodules with different sizes and shapes and, finally, the ability to integrate with the Electronic Medical Record Systems and Picture Archiving and Communication Systems. Based on this analysis, we can say that further research is needed to develop current techniques and that new algorithms are needed to overcome the identified drawbacks

Prognostic value of epidermal growth factor receptors in gastric cancer: a survival analysis by Weibull model incorporating long-term survivors

BACKGROUND: There is no consensus about the prognostic role of HER2 expression and that of other members of the EGFR family in gastric cancer patients. The aim of this study was to evaluate the prognostic value of the EGFR family in gastric cancer. METHODS: This retrospective study included 201 patients with gastric and esophagogastric junction adenocarcinoma stages 0–IV (AJCC 6th edition) who underwent primary tumor resection. Tissues from primary tumors were analyzed by tissue microarray technology and immunohistochemistry. Correlations between receptor expression and clinicopathological characteristics were performed according to the chi-square test. Survival analysis was calculated according to the Weibull model with a mixture model incorporating long-term survivors. Multivariate analysis of prognostic factors was performed by a regression model incorporating long-term survivors with the Weibull distribution. RESULTS: Membrane expression of HER1, HER2, and HER4 were 9, 17, and 15 %, respectively. No membrane expression of HER3 was observed. Cytoplasmic expression of HER1, HER3, and HER4 were 45, 62, and 24 %, respectively. HER2 and HER3 expression were correlated (p < 0.001) and associated with intestinal-type histology (p = 0.001 and p < 0.001, respectively) and advanced age (p = 0.011 and p = 0.008, respectively). According to a regression model adjusted for age, surgical radicality, surgical modality, Laurén histology, adjuvant therapy, TNM stage, and receptor expressions, only TNM stage showed prognostic influence. CONCLUSIONS: According to analysis by a parametric model, the EGFR family did not have prognostic influence in the gastric cancer population studied. The data presented showed a correlation between HER2 and HER3 expression, which might suggest a potential role for HER2–HER3 heterodimerization inhibitors

Group-IV graphene- and graphane-like nanosheets

We performed a first principles investigation on the structural and electronic properties of group-IV (C, SiC, Si, Ge, and Sn) graphene-like sheets in flat and buckled configurations and the respective hydrogenated or fluorinated graphane-like ones. The analysis on the energetics, associated with the formation of those structures, showed that fluorinated graphane-like sheets are very stable, and should be easily synthesized in laboratory. We also studied the changes on the properties of the graphene-like sheets, as result of hydrogenation or fluorination. The interatomic distances in those graphane-like sheets are consistent with the respective crystalline ones, a property that may facilitate integration of those sheets within three-dimensional nanodevices