Molecular mobility, composition and structure analysis in glycerol plasticised chitosan films

This study was developed with the purpose to investigate the effect of polysaccharide/plasticiser concentration on the microstructure and molecular dynamics of polymeric film systems, using transmission electron microscope imaging (TEM) and nuclear magnetic resonance (NMR) techniques. Experiments were carried out in chitosan/glycerol films prepared with solutions of different composition. The films obtained after drying and equilibration were characterised in terms of composition, thickness and water activity. Results show that glycerol quantities used in film forming solutions were responsible for films composition; while polymer/total plasticiser ratio in the solution determined the thickness (and thus structure) of the films. These results were confirmed by TEM. NMR allowed understanding the films molecular rearrangement. Two different behaviours for the two components analysed, water and glycerol were observed: the first is predominantly moving free in the matrix, while glycerol is mainly bounded to the chitosan chain. (C) 2013 Elsevier Ltd. All rights reserved.

An SEM investigation of the pozzolanic activity of a waste catalyst oil refinery

The most active phase of the fluid catalytic cracking (FCC) catalyst, used in oil refinery, is zeolite-Y which is an aluminosilicate with a high internal and external surface area responsible for its high reactivity. Waste FCC catalyst is potentially able to be reused in cement-based materials - as an additive - undergoing a pozzolanic reaction with calcium hydroxide (Ca(OH)2) formed during cement hydration [1-3]. This reaction produces additional strength-providing reaction products i.e., calcium silicate hydrate (C-S-H) and hydrous calcium aluminates (C-A-H) which exact chemical formula and structure are still unknown. Partial replacement of cement by waste FCC catalyst has two key advantages: (1) lowering of cement production with the associated pollution reduction as this industry represents one of the largest sources of man-made CO2 emissions, and (2) improving the mechanical properties and durability of cement-based materials. Despite these advantages, there is a lack of fundamental knowledge on pozzolanic reaction mechanisms as well as spatial distribution of porosity and solid phases interactions at the microstructural level and consequently their relationship with macroscopical engineering properties of catalyst/cement blends. Within this scope, backscattered electron (BSE) images acquired in a scanning electron microscope (SEM) equipped with Energy-Dispersive Spectroscopy (EDS) and by X-ray diffraction were used to investigate chemical composition of hydration products and to analyse spatial information of the microstructure of waste FCC catalyst blended cement mortars. For this purpose mortars with different levels of cement substitution by waste catalyst as well as with different hydration ages, were prepared. The waste FCC catalyst used is produced by the Portuguese refinery company Petrogal S.A.

Synthesis of organometallic Ruthenium(II) complexes with strong activity against several human canceer cell lines

A new family of "RuCp" (Cp=eta(5)-C5H5) derivatives with bidentate N,O and N,N'-heteroaromatic ligands revealed outstanding cytotoxic properties against several human cell lines namely, A2780, A2780CisR, HT29, MCF7, MDAMB231, and PD. IC50 values were much lower than those found for cisplatin. Crystal structure of compound 4 was determined by X-ray diffraction studies. Density functional theory (DFT) calculations performed for compound 1 showed electronic flow from the ruthenium center to the coordinated bidentate ligand, in agreement with the electrochemical studies and the existence of a metal-to-ligand charge-transfer (MLCT) band evidenced by spectroscopic data.

Structure to function studies in UDP-glucose dehydrogenases and nitroreductases

The thesis is divided into two parts corresponding to structural studies on two different proteins. The first part concerns the study of two UDP-glucose dehydrogenases (UGDs) from Sphingomonas elodea ATCC 31461 and Burkholderia cepacia IST 408, both involved in exopolysaccharide production. Their relevance arises because some of these bacterial exopolysaccharides are valuable as established biotechnological products, the former case, whilst others are highly problematic, when used by pathogens in biofilm formation over biological surfaces, as the latter case, namely in the human lungs. The goal of these studies is to increase our knowledge regarding UGDs structural properties, which can potentiate either the design of activity enhancers to respond to the increased demand of useful biofilms, or the design of inhibitors of biofilm production, in order to fight invading pathogens present in several infections. The thesis reports the production and crystallisation of both proteins, the determination of initial phases by single-wavelength anomalous dispersion (SAD) in S. elodea crystals using a seleno-methionine isoform, and phasing of B. cepacia crystals by molecular replacement (MR) using the S. elodea model, as well as the refinement, structural analysis and comparison between the several UGDs structures available during this work.(...)

Hydrogenating activity of Pt/zeolite catalysts focusing acid support and metal dispersion influence

Toluene hydrogenation was studied over catalysts based on Pt supported on large pore zeolites (HUSY and HBEA) with different metal/acid ratios. Acidity of zeolites was assessed by pyridine adsorption followed by FTIR showing only small changes before and after Pt introduction. Metal dispersion was determined by H2–O2 titration and verified by a linear correlation with the intensity of Pt0–CO band obtained by in situ FTIR. It was also observed that the electronic properties of Pt0 clusters were similar for the different catalysts. Catalytic tests showed rapid catalyst deactivation with an activity loss of 80–95% after 60 min of reaction. The turnover frequency of fresh catalysts depended both on metal dispersion and the support. For the same support, it changed by a 1.7-fold (HBEA) and 4.0-fold (HUSY) showing that toluene hydrogenation is structure-sensitive, i.e. hydrogenating activity is not a unique function of accessible metal. This was proposed to be due to the contribution to the overall activity of the hydrogenation of adsorbed toluene on acid sites via hydrogen spillover. Taking into account the role of zeolite acidity, the catalysts series were compared by the activity per total adsorbing sites which was observed to increase steadily with nPt/(nPt + nA). An increase of the accessible Pt atoms leads to an increase on the amount of spilled over hydrogen available in acid sites therefore increasing the overall activity. Pt/HBEA catalysts were found to be more active per total adsorbing site than Pt/HUSY which is proposed to be due to an augmentation in the efficiency of spilled over hydrogen diffusion related to the proximity between Pt clusters and acid sites. The intervention of Lewis acid sites in a greater extent than that measured by pyridine adsorption may also contribute to this higher activity of Pt/HBEA catalysts. These results reinforce the importance of model reactions as a closer perspective to the relevant catalyst properties in reaction conditions.

Novel coordination polymers with (Pyrazolato)-based tectons: catalytic activity in the peroxidative oxidation of alcohols and cyclohexane

Coupling five rigid or flexible bis(pyrazolato)based tectons with late transition metal ions allowed us to isolate 18 coordination polymers (CPs). As assessed by thermal analysis, all of them possess a remarkable thermal stability, their decomposition temperatures lying in the range of 340-500 degrees C. As demonstrated by N-2 adsorption measurements at 77 K, their Langmuir specific surface areas span the rather vast range of 135-1758 m(2)/g, in agreement with the porous or dense polymeric architectures retrieved by powder X-ray diffraction structure solution methods. Two representative families of CPs, built up with either rigid or flexible spacers, were tested as catalysts in (0 the microwave-assisted solvent-free peroxidative oxidation of alcohols by t-BuOOH, and (ii) the peroxidative oxidation of cydohexane to cydohexanol and cydohexanone by H2O2 in acetonitrile. Those CPs bearing the rigid spacer, concurrently possessing higher specific surface areas, are more active than the corresponding ones with the flexible spacer. Moreover, the two copper(I)-containing CPs investigated exhibit the highest efficiency in both reactions, leading selectively to a maximum product yield of 92% (and TON up to 1.5 x 10(3)) in the oxidation of 1-phenylethanol and of 11% in the oxidation of cydohexane, the latter value being higher than that granted by the current industrial process.

Sentido de coerência : ligação materno-fetal e estilo de vida da mulher durante a gravidez

RESUMO - Um dos grandes desafios actuais enfrentados pela Saúde Pública diz respeito ao fardo representado pelas doenças crónicas não transmissíveis enquanto co-responsáveis pela maioria das mortes que ocorrem no mundo, pela significativa e progressiva redução da qualidade de vida e aumento das incapacidades dos indivíduos afectados e por uma fasquia bastante elevada das despesas em saúde. Entretanto, a complexa dinâmica genética, biológica, psicológica, afectiva, sócio-cultural e ambiental que envolve o comportamento humano, tão amplamente relacionado com algumas destas doenças – doenças cardiovasculares, alguns tipos de cancro, obesidade, hipertensão, diabetes e doenças osteo-articulares – impõe o desafio constante da busca de novas e efectivas intervenções em promoção da saúde que influenciem positivamente os estilos de vida dos indivíduos, dos grupos e das comunidades. Sendo o sentido de coerência um traço da personalidade do indivíduo desenvolvido sob a influência directa ou indirecta dos mesmo factores acima referidos, o estabelecimento de uma relação entre este constructo e os comportamentos humanos pode revelar-se promissor para a elaboração de novas intervenções em promoção da saúde. Por sua vez, a gravidez, talvez por influência da ligação materno-fetal, pode representar um ponto de viragem na vida da mulher no que respeita ao sentido de coerência e aos comportamentos de saúde e um bom começo na vida do bebé que irá nascer sob a influência dos mesmos. Com a finalidade de contribuir para a construção de intervenções efectivas em promoção da saúde, através da descoberta de prováveis potencialidades salutogénicas dos constructos referidos – sentido de coerência e ligação materno-fetal –, foi desenvolvido um estudo quantitativo, observacional que teve por objectivos: ampliar o conhecimento sobre as mudanças do sentido de coerência no decorrer da vida, especificamente durante a gravidez; ampliar o conhecimento acerca das relações de alguns factores de natureza sócio-demográfica, psico-afectiva e obstétrica com o sentido de coerência das mulheres grávidas e com a ligação materno-fetal; e identificar possíveis relações entre o sentido de coerência, a ligação materno-fetal e o estilo de vida das mulheres grávidas, este último representado pelos hábitos alimentares, consumo de cafeína, consumo de álcool, hábitos tabágicos, prática regular de actividade física e ganho de peso durante a gravidez. O presente relatório descreve a concepção e os resultados deste estudo, que envolveu a uma amostra de 61 mulheres grávidas que estavam a ser acompanhadas nos serviços de saúde materna dos Centros de Saúde de Carnaxide extensão Linda-a-Velha e de Oeiras, no Distrito de Lisboa, Portugal, entre os meses de Fevereiro e Julho de 2005. Os resultados demonstram que, para a amostra de 61 mulheres grávidas que responderam ao inquérito por questionário de auto-resposta, foram encontradas associações estatisticamente significativas entre o sentido de coerência e a escolaridade e entre o sentido de coerência e a percepção do próprio estado de saúde. Além disso, foi encontrada alguma evidência das associações entre o sentido de coerência e a faixa etária, estado civil e rendimento mensal familiar e foi observada alguma tendência para que as mulheres grávidas com níveis de sentido de coerência mais elevados consumissem menos álcool do que as mulheres grávidas com níveis de sentido de coerência inferiores. Entretanto, as demais associações testadas não foram confirmadas. Relativamente à ligação materno-fetal, foram encontradas, para a amostra de 41 mulheres grávidas que participaram do segundo momento de colheita de dados do estudo, entre a 20ª e a 24ª semanas de gravidez, associações estatisticamente significativas com a escolaridade e o nível de rendimento familiar das mulheres grávidas, não tendo sido confirmadas as demais associações testadas. Embora não tenham sido estatisticamente evidenciadas as relações entre o sentido de coerência e a ligação materno-fetal e entre estes e os comportamentos de saúde, o carácter preliminar destes resultados, devido à subjectividade do processo de selecção não probabilístico da amostra estudada e à reduzida dimensão desta amostra, e a escassez de estudos descritos na literatura fazem com que seja prudente a realização de estudos de follow-up, com amostras de maiores dimensões, aleatórias e representativas da população, para que sejam estabelecidas quaisquer conclusões acerca destas questões.-----------------------------ABSTRACT - One of the greatest challenges faced by Public Health in nowadays is the burden represented by chronic diseases as co-responsible for the majority of deaths that occurs in the world, for the meaningful and progressive reduction of quality of life and increase of disabilities in affected individuals and for an important part of health expenses. However, the complexity of the genetic, biological, psychological, emotional, social, cultural and environmental dynamics that involves human behaviours related to some of these diseases – cardiovascular diseases, some kind of cancers, obesity, hypertension, diabetes and joint and bone diseases – poses the continuous challenge of searching for new and effective interventions of health promotion that positively influence individuals, groups and community lifestyles. Due to the fact that sense of coherence is an individual personality trace directly or indirectly influenced by the same factors listed above, the discovery of a relationship between this construct and human behaviours might be promising to the creation of new health promotion interventions. On the other hand, pregnancy may represent a turn point to the mother’s life and a good start in the baby’s life in relation to sense of coherence and health behaviours and It might occur because of the influence of maternal-fetal attachment. With the purpose of contributing with the creation of effective health promotion interventions through the discovery of probable salutogenic potentials in the referred constructs – sense of coherence and maternal-fetal attachment – , it was developed a quantitative observational study with the following objectives: to increase knowledge about changes in sense of coherence throughout life, specifically during pregnancy; to increase knowledge about the relationship between sense of coherence and maternal-fetal attachment and some social, demographical, psychological, emotional and obstetric factors of pregnant women; to identify probable relationships between sense of coherence, maternal-fetal attachment and pregnant women’s lifestyles, represented by diet habits, caffeine consumption, alcohol consumption, smoking habits, physical activity habits and weigh gain during pregnancy. This report describes the structure and the findings of this study involving a sample of 61 pregnant women who had been followed by health professionals in the mother health services of Carnaxide (Linda-a-Velha unity) and Oeiras Health Centres, in Lisbon, Portugal, between February and July of 2005. The results show that, for the 61 pregnant women who filled the self-reported questionnaire, it was found a statistically significant association between sense of coherence and education level. It was also found some evidence of the associations between sense of coherence and age, marital status and mensal household income and a trend toward pregnant women with higher levels of sense of coherence to drink less alcoholic beverages than pregnant women with lower levels of sense of coherence. However, the others associations tested were not confirmed. Regarding maternal-fetal attachment, it was found, for the sample of 41 women who participated in the second moment of data collection, between the 20th and the 24th week of pregnancy, statistically significant associations with education level and mensal household income. The others associations tested were not confirmed. Although the associations between sense of coherence and maternal-fetal attachment and between these constructs and health behaviours were not confirmed, all findings presented here are considered preliminary because of small dimension of sample and non-probabilistic criteria used for sample selection. What’s more, there are almost no studies described in the literature which could confirm or contradict these findings. Therefore, it is better to be careful and develop follow-up studies, with bigger and representative of population samples, before draw any conclusions about these theme.

Febrifugine derivative antimalarial activity: quantum mechanical predictors

Plasmodium falciparum resistant strain development has encouraged the search for new antimalarial drugs. Febrifugine is a natural substance with high activity against P. falciparum presenting strong emetic property and liver toxicity, which prevent it from being used as a clinical drug. The search for analogues that could have a better clinical performance is a current topic. We aim to investigate the theoretical electronic structure by means of febrifugine derivative family semi-empirical molecular orbital calculations, seeking the electronic indexes that could help the design of new efficient derivatives. The theoretical results show there is a clustering in well-defined ranges of several electronic indexes of the most selective molecules. The model proposed for achieving high selectivity was tested with success.

The inhibitory activity of synthetic compounds and ions against transporters of multi-drug resistant bacteria

RESUMO: Sessenta e três derivados de hidantoína foram utilizados para avaliar possíveis efeitos de modulação na actividade das bombas de efluxo (BE) na Salmonella NCTC 13349 utilizando um método fluorimétrico semi-automático. Nenhum dos compostos apresentaram actividade anti-bacteriana até concentrações de 240 mg/L. Entre todos os compostos, SZ-7 demonstrou possuir propriedades de modulação de effluxo na presença de glucose. Para testar esta actividade, estirpes de Salmonella resistentes à ciprofloxacina, induzidas a elevados níveis de resistência com sobre-expressão de BE, foram expostas ao SZ-7. Este derivado afectou a susceptibilidade das estirpes à ciprofloxacina. Uma vez que os 63 compostos estudados apresentaram pouco efeito inibitório /cumulativo, apesar de serem conhecidos pelos seus efeitos moduladores de BE-dependentes de iões em eucariotas, foi questionado o papel dos iões na regulação de BE bacterianas, que poderão influenciar a eficácia de novos compostos. Para este estudo, utilizamos a Escherichia coli AG100 como modelo, devido ao extenso conhecimento no que respeita a estrutura e actividade das BE. Devido à importância de iões de cálcio (Ca2+) nos canais de transporte membranar e na actividade de ATPases, a sua actividade na modulação do efluxo foi investigada. De resultados anteriormente obtidos concluiu-se que a pH 5 o efluxo é independente de energia metabólica; contudo, a pH 8 é absolutamente dependente, sendo que o Ca2+ é indispensável para manter a actividade das ATPases bacterianas. A acumulação/effluxo de EtBr pela E. coli AG100 foi determinada na presença/ausência de Ca2+, clorpromazina (inibidor de ligação de Ca2+ a proteínas), e ácido etilenodiamino tetra-acético (quelante de Ca2+). Acumulação/effluxo aumentou a pH 8, contudo o Ca2+ reverte estes efeitos evidenciando a sua importância no funcionamento das BE bacterianas. Em resumo este trabalho colocou em evidência que muitos aspectos bioquímicos e bioenergéticos devem ser tomados em consideração no estudo da resistência bacteriana mediada por BE.------- ABSTRACT: Sixty-three hydantoin derivatives were evaluated for their modulating effects on efflux pump (EP) activity of Salmonella NCTC 13349 utilizing a semi-automatic fluorometric method. None of the compounds presented antibacterial activities at concentrations as high as 240 mg/L. Among all compounds, SZ-7 showed possible efflux modulating activity in the presence of glucose, indicative of a potential EP inhibitor. To verify its potential effects, ciprofloxacin-resistant Salmonella strains, induced to high level resistance with over-expressing EPs, were exposed to SZ-7. This derivative affected the susceptibility of the ciprofloxacin-resistant strains. Since the 63 compounds studied had very low inhibitory/accumulative effects, even though their known for being efficient in modulating ion-driven eukaryotic EPs, we questioned whether ions had a leading role in regulating bacterial EPs, influencing the effectiveness of new compounds. For this study we used Escherichia coli AG100 as a model, due to the extensive knowledge on its EPs structure and activity. Owing the importance of calcium ions (Ca2+) for membrane transport channels and activity of ATPases, the role of Ca2+ was investigated. From previous results we concluded that at pH 5 efflux is independent of metabolic energy; however, at pH 8 it is entirely dependent of metabolic energy and the Ca2+ ions are essential to maintain the activity of bacterial ATPases. Accumulation and efflux of ethidium bromide (EtBr) by E. coli AG100 was determined in the presence and absence of Ca2+, chlorpromazine (inhibitor of Ca2+-binding to proteins), and ethylenediaminetetraacetic acid (Ca2+ chelator). Accumulation of EtBr increased at pH 8; however Ca2+ reversed these effects providing information as to the importance of this ion in the regulation of bacterial EP systems. Overall this work puts in evidence that many biochemical and bioenergetic aspects related to the strains physiology need to be taken into consideration in bacterial drug resistance mediated by EPs.

Insights into human carboxylesterase 2 stability and activity in vivo and in vitro

Dissertation to obtain a Master Degree in Biotechnology

APPLICATION OF 6-NITROCOUMARIN AS A SUBSTRATE FOR THE FLUORESCENT DETECTION OF NITROREDUCTASE ACTIVITY IN Sporothrix schenckii

Introduction Sporothrix schenckii is a thermal dimorphic pathogenic fungus causing a subcutaneous mycosis, sporotrichosis. Nitrocoumarin represents a fluorogenic substrate class where the microbial nitroreductase activity produces several derivatives, already used in several other enzyme assays. The objective of this study was the analysis of 6-nitrocoumarin (6-NC) as a substrate to study the nitroreductase activity in Sporothrix schenckii. Methods Thirty-five samples of S. schenckii were cultivated for seven, 14 and 21 days at 35 °C in a microculture containing 6-nitrocoumarin or 6-aminocoumarin (6-AC) dissolved in dimethyl sulfoxide or dimethyl sulfoxide as a negative control, for posterior examination under an epifluorescence microscope. The organic layer of the seven, 14 and 21-day cultures was analyzed by means of direct illumination with 365 nm UV light and by means of elution on G silica gel plate with hexane:ethyl acetate 1:4 unveiled with UV light. Results All of the strains showed the presence of 6-AC (yellow fluorescence) and 6-hydroxylaminocoumarin (blue fluorescence) in thin layer chromatography, which explains the green fluorescence observed in the fungus structure. Conclusion The nitroreductase activity is widely distributed in the S. schenckii complex and 6-NC is a fluorogenic substrate of easy access and applicability for the nitroreductase activity detection.

Ageing on commercial automotive catalysts, a structure reactivity study

Increasingly stringed regulations for diesel engine emissions have a significant impact on the required efficiency of DOC. Lowered DOC oxidation efficiency due to thermal aging effects influences the efficiency of the exhaust aftertreatment systems downstream of the DOC. In this work carried out in the Jean Le Rond d’Alembert Institute the effect of hydrothermal aging on the reactivity and structure of a commercial DOC was investigated. The characterization of the catalytic performance was carried out on a synthetic gas bench using carrots catalyst under conditions close to the realistic conditions i.e. using a synthetic gas mixture, representative of the exhaust gases from diesel engines. Different structural characterization techniques were performed: textural and morphological proprieties were analyzed by BET and TEM, the characterization of the presented crystallographic phases was performed by DRX and the determination of the number of reducible species was possible by TPR. TEM results shown, an increase of the metal particle size with the aging caused by the agglomeration of metal particles, revealing the presence of metal sintering. DRX results also suggest the presence of support sintering. Furthermore, DRX and BET results unexpectedly reveal that the most drastic aging conditions used actually activated the catalyst surface. As expected, the aging affected negatively the catalyst performance on the oxidation of methane and CO, however an improvement of the NO oxidation performance with the aging was observed. Nevertheless, for the aging conditions used, catalytic activity results show that the influence of aging in DOC performance was not significant, and therefore, more drastic aging conditions must be used.

Antimicrobial activity of bergenin from Endopleura uchi (Huber) Cuatrec

Endopleura uchi (Huber) Cuatrec. is an Amazon species traditionally used as treatment for inflammations and female disorders. Bergenin was isolated from ethyl acetate fraction of bark of E. uchi by using column chromatography over sephadex LH-20 and then silica gel 60 flash. Its structure was identified on the basis of its NMR spectra. The antimicrobial activity of bergenin and fractions of methanol extract of E. uchi were evaluated against ATCC microorganisms (Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida albicans, C. guilliermondii, Aspergillus flavus, A. nidulans). Clinically isolated strains of all of these microorganisms, along with C. tropicalis, A. niger, Shigella sonnei, Serratia marcenses and Klebsiella pneumoniae were also evaluated. The growth inhibition caused by bergenin, extracts and fractions of E. uchi against ATCC microorganisms were similar to the inhibition to microorganisms clinically isolated. The ethyl acetate fraction and the isolate bergenin inhibit the growth of the yeasts C. albicans, C. tropicalis, and C. guilliermondii, but present lower activity against filamentous fungi Aspergillus flavus, A. nidulans, A. niger, and did not inhibit the Gram positive and Gram negative bacteria. The activity of the ethyl acetate fraction and bergenin are in agreement wit its high concentration found in bark extract of E. uchi. Moreover, the selective activity against three Candida species helps to understand its traditional use against infections that affect women.

RNA-seq analysis of the Quercus suber root response to drought

Dissertação de mestrado em Plant Molecular Biology, Biotechnology and Bioentrepreneurship

Genetic regulatory mechanisms by means of extended interactive Petri nets

In our work we have chosen to integrate formalism for knowledge representation with formalism for process representation as a way to specify and regulate the overall activity of a multi-cellular agent. The result of this approach is XP,N, another formalism, wherein a distributed system can be modeled as a collection of interrelated sub-nets sharing a common explicit control structure. Each sub-net represents a system of asynchronous concurrent threads modeled by a set of transitions. XP,N combines local state and control with interaction and hierarchy to achieve a high-level abstraction and to model the complex relationships between all the components of a distributed system. Viewed as a tool XP,N provides a carefully devised conflict resolution strategy that intentionally mimics the genetic regulatory mechanism used in an organic cell to select the next genes to process.