Experimental Reinforcement of Wood Beams

Rehabilitation is becoming more and more usual in the construction sector in Portugal. The introduction of newer construction materials and technical know-how of integrating different materials for achieving desired engineering goals is an important step to the development of the sector. Wood industry is also getting more and more adapted to composite technologies with the introduction of the so called “highly engineered wood products” and with the use of modification treatments. This work is an attempt to explain the viability of using stainless steel and glass fibre reinforced polymer (GFRP) as reinforcements in wood beams. This thesis specifically focuses on the flexural behaviour of Portuguese Pine unmodified and modified wood beams. Two types of modification were used: 1,3-dimethylol-4,5- dihydroxyethyleneurea (DMDHEU) resin and amid wax. The behaviour of the material was analysed with a nonlinear model. The latter model simulates the behaviour of the reinforced wood beams under flexural loading. Small-scale beams (1:15) were experimented in flexural bending and the experimental results obtained were compared with the analytical model results. The experiments confirm the viability of the reinforcing schemes and the working procedures. Experimental results showed fair agreement with the nonlinear model. A strength increase between 15% and 80% was achieved. Stiffness increased by 40% to 50% in beams reinforced with steel but no significant increase was achieved with the glass fibre reinforcement.

New modified electrochemical conductive paper support for BSA detection

Chemical sensors and biosensors are widely used to detect various kinds of protein target biomolecules. Molecularly Imprinted Polymers (MIPs) have raised great interest in this area, because these act as antibody-like recognition materials, with high affinity to the template molecule. Compared to natural antibodies, these are also of lower cost and higher stability. There are different types of supports used to carry MIP materials, mostly of these made of gold, favourably assembled on a Screen Printed Electrode (SPE) strategy. For this work a new kind of support for the sensing layer was developed: conductive paper. This support was made by modifying first cellulose paper with paraffin wax (to make it waterproof), and casting a carbon-ink on it afterwards, to turn it conductive. The SPAM approach previously reported in1 was employed herein to assemble to MIP sensing material on the conductive paper. The selected charged monomers were (vinylbenzyl) trimethlammonium chloride (positive charge) or vinylbenzoic acid (negative charge), used to generate binding positions with single-type charge (positive or negative). The non-specific binding area of the MIP layer was assembled by chronoamperometry-assisted polymerization (at 1 V, for 60, 120 or 180 seconds) of vinylbenzoate, cross-linked with ethylene glycol vinyl ether. The BSA biomolecules lying within the polymeric matrix were removed by Proteinase K action. All preparation stages of the MIP assembly were followed by FTIR, Raman spectroscopy and, electrochemical analysis. In general, the best results were obtained for longer polymerization times and positively charged binding sites (which was consistent with a negatively-charged protein under physiological pH, as BSA). Linear responses against BSA concentration ranged from 0.005 to 100 mg/mL, in PBS buffer standard solutions. The sensor was further calibrated in standard solutions that were prepared in synthetic or real urine, and the analytical response became more sensitive and stable. Compared to the literature, the detection capability of the developed device is better than most of the reported electrodes. Overall, the simplicity, low cost and good analytical performance of the BSA SPE device, prepared with positively charged binding positions, seems a suitable approach for practical application in clinical context. Further studies with real samples are required, as well as gathering with electronic-supporting devices to allow on-site readings.

A new biomimetic sensor for detecting carnitine, a potential biomarker in ovarian cancer

1st ASPIC International Congress

Effects of tissue handling and processing steps on PCR for detection of Mycobacterium tuberculosis in formalin-fixed paraffin-embedded samples

Development and standardization of reliable methods for detection of Mycobacterium tuberculosis in clinical samples is an important goal in laboratories throughout the world. In this work, lung and spleen fragments from a patient who died with the diagnosis of miliary tuberculosis were used to evaluate the influence of the type of fixative as well as the fixation and paraffin inclusion protocols on PCR performance in paraffin embedded specimens. Tissue fragments were fixed for four h to 48 h, using either 10% non-buffered or 10% buffered formalin, and embedded in pure paraffin or paraffin mixed with bee wax. Specimens were submitted to PCR for amplification of the human beta-actin gene and separately for amplification of the insertion sequence IS6110, specific from the M. tuberculosis complex. Amplification of the beta-actin gene was positive in all samples. No amplicons were generated by PCR-IS6110 when lung tissue fragments were fixed using 10% non-buffered formalin and were embedded in paraffin containing bee wax. In conclusion, combined inhibitory factors interfere in the detection of M. tuberculosis in stored material. It is important to control these inhibitory factors in order to implement molecular diagnosis in pathology laboratories.

Mechanical properties of chemically modified portuguese pinewood

To turn wood into a construction material with enhanced properties, many methods of chemical modification have been developed in the last few decades. In this work, mechanical properties of pine wood were chemically modified, compared and evaluated. Maritime pine wood (Pinus pinaster) was modified with four chemical processes: 1,3-dimethylol-4,5- dihydroxyethyleneurea, N-methylol melamine formaldehyde, tetra-alkoxysilane and wax. The following mechanical properties were assessed experimentally: Modulus of elasticity measured statically, stiffness stabilization efficiency in different climates (30 and 87% of relative humidity), modulus of rupture, work maximum load, impact bending strength, compression, tensile and shear strength at indoor conditions (65% of relative humidity). In both types of active principle of modification, cell wall or lumen fill, no significant changes on the bending stiffness (modulus of elasticity) were found. In the remaining properties analysed significant changes in the modified wood-material took place compared to unmodified wood control: - Cell wall modification was the most effective method to achieve high stiffness stabilization efficiency (up to 60%) and also increased compression strength (up to 230%). However, modulus of rupture, tensile, shear and the impact bending strength were reduced by both resins, but in a varying extent, where the N-methylol melamine formaldehyde endured less reduction than 1,3-dimethylol-4,5-dihydroxyethyleneurea resin. In the latter, reduction up to 60% can take place. - In the lumen fill modification: tetra-alkoxysilane has no effect in the mechanical properties. Although, a slight increase in shear strength parallel to the grain was found. Wax specimens have shown a slight increase in bending strength, compression, tensile and shear strength as well as in the absorption energy capacity.

Influence of abiotic stress factors on VOCs emission from Portuguese rice paddy fields: relation with increased climate change

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente Perfil de Gestão de Sistemas Ambientais

Atividade antifúngica de Caryocar brasiliensis (Caryocaraceae) sobre Cryptococcus neoformans

A grande incidência de criptococose em decorrência do aumento crescente de indivíduos imunodeprimidos e os efeitos colaterais aos fármacos utilizados para o tratamento desta infecção, tem incentivado a pesquisa de novos agentes antifúngicos. Através da técnica de diluição em ágar, foi verificada a atividade antifúngica (in vitro) de diferentes constituintes de Caryocar brasiliensis sobre Cryptococcus neoformans. Verificou-se que a cera epicuticular retirada da folha, coletada em período de baixo índice pluviométrico (170,8mm de água), foi a parte mais ativa da planta, inibindo o crescimento de 91,3% (21/23) dos isolados de Cryptococcus neoformans em concentração < a 250µg/mL.

Genetic breeding on the bee Melipona scutellaris (Apidae, Meliponinae)

A selection of queens of Melipona scutellaris through the most productive colonies were carried out during eight months in an orange honeyflow. Each of the colonies was evaluated by its production, that is, the gross weight production ( pollen, brood, geopropolis and wax of each hive). With this data a coefficient of repeatability was estimated by the intraclass correlation method, obtained r = 0.835 ± 0.071. The repeatibility is very high showing that the analysed data (production) is repeatable. Selection was then carried out using the regression coefficient of each colony and the respective production gain. Using these data the colonies were divided into three groups according to the method Vencovsky and Kerr (1982): a with the colonies of highest productivity, b of least productivity, and c of intermediary productivity. Colonies with the highest production (Group a) gave their queens to those of the lowest production (Group b) after their queens were taken out and killed; while those of intermediate (Group c) stayed with the same queens during the entire experiment both before and after the selection. The modifications in weight, that is, the genetic response was (R)= 7.98 gr per day which indicated a selection gain. The estimate of the realized herdability is twice the rate of the response to selection (R) by the selection differential (S2). That is then h²R=2(R/S2) then h²R= 0.166

Characterization of physical, mechanical and chemical properties of quiscal fibres : the influence of atmospheric DBD plasma treatment

This paper reports the first attempt of characterizing various physical, mechanical and chemical properties of Quiscal fibres, used by the native communities in Chile and investigating the influence of atmospheric dielectric barrier discharge plasma treatment on various properties such as diameter and linear density, fat, wax and impurity%, moisture regain, chemical elements and groups, thermal degradation, surface morphology, etc. According to the experimental observations, Quiscal fibre has lower tenacity than most of the technical grade natural fibres such as sisal, hemp, flax, etc., and plasma treatment at optimum dose improved its tenacity to the level of sisal fibres. Plasma treatment also reduced the amount of fat, wax and other foreign impurities present in Quiscal fibres as well as removed lignin and hemicellulose partially from the fibre structure. Plasma treatment led to functionalization of Quiscal fibre surface with chemical groups, as revealed from attenuated total reflection spectroscopy and also confirmed from the elemental analysis using energy dispersive Xray technique and pH and conductivity measurements of fibre aqueous extract. The wetting behavior of Quiscal fibre also improved considerably through plasma treatment. However, untreated and plasma treated Quiscal fibres showed similar thermal degradation behavior, except the final degradation stage, in which plasma treated fibres showed higher stability and incomplete degradation unlike the untreated fibres. The experimental results suggested that the plasma treated Quiscal fibres, like other technical grade natural fibres, can find potential application as reinforcement of composite materials for various industrial applications.

Molecular regulation of flowering induction in Quercus suber

Dissertação de mestrado em Plant Molecular Biology, Biotechnology and Bioentrepeneurship

Physicochemical properties and antioxidant capacity of propolis of stingless bees (Meliponinae) and Apisfrom two regions of Tocantins, Brazil

ABSTRACTThe composition of propolis depends on time, vegetation and the location of the collection area. The objective of this study was to determine the physicochemical characteristics, the concentration of phenol compounds and the antioxidant capacity of propolis of native stingless bees (Meliponinae)and Apis from the State of Tocantins. Extraction with 80% ethanol (v/v) was performed in order to obtain the extracts. Parameters examined were: propolis mass loss by desiccation at 105 ºC, ashes, wax concentration and pH. Furthermore, the propolis antioxidant activity was measured, as well as the total concentration of phenol compounds. The extracts were also analyzed by high performance liquid chromatography. The total concentration of phenol compounds varied between 121.78 and 631.29 (mg GAE g-1). The antioxidant activity expressed by the value of CE50 varied between 29.81 and 845.38 µg mL-1. High performance liquid chromatography analysis allowed us to infer the existence of phenol compounds. The results indicated that the studied propolis samples constitute good sources of natural antioxidants. The variety of phenol compounds identified in this study, and the diverse biological functions reported in literature for these compounds indicated that this stingless bee propolis (Meliponinae) and Apis has a high pharmacological potential.

Caracterização farmacognóstica de Piper arboreum var. arboreum e P. tuberculatum (Piperaceae)

RESUMO Piper arboreum Aubl. var. arboreum e P. tuberculatum Jacq. (Piperaceae), conhecidas como pimenta-longa, são comercializadas como produtos tradicionais fitoterápicos e, frequentemente, identificadas erroneamente, não havendo relatos sobre controle de qualidade dessas espécies. O objetivo do trabalho foi preparar e caracterizar drogas vegetais foliares e caulinares dessas espécies para estabelecer-lhes parâmetros de autenticidade botânica e grau de pureza para o controle de qualidade. Foram utilizados métodos padrões para o preparo e análises estrutural e físico-química das drogas vegetais. São caracteres diagnósticos macroscópicos para distinguir as drogas vegetais íntegras: tamanho, forma, cor, sabor, textura, características da superfície de fratura e da secção transversal e os padrões de venação foliar. São caracteres diagnósticos para distinguir as drogas vegetais pulverizadas: padrões de cutícula e cera epicuticular, tipos de tricoma e espessamento parietal dos elementos traqueais e a forma do hilo dos grãos de amido. Emergências são marcadores morfológicos chave para as drogas vegetais de P. tuberculatum. Os valores dos parâmetros físico-químicos foram similares nas drogas vegetais das espécies, exceto o de cinzas ácido-insolúveis que foi maior nas drogas vegetais caulinares de P. arboreum var. arboreum. As maiores concentrações de metais ocorreram nas drogas vegetais de P. arboreum var. arboreum. As concentrações mais elevadas foram de Al, Cu, Mn e V e as mais baixas de Cd, Co e Hg. Os resultados obtidos poderão ser utilizados como parâmetros de controle de qualidade para as drogas vegetais de ambas as espécies.

Hydrocarbonoclastic bacteria: from bioremediation to bioenergy feedstock

Tese de Doutoramento em Engenharia Química e Biológica.

Beeswax organogels: Influence of gelator concentration and oil type in the gelation process

This work focused on how different types of oil phase, MCT (medium chain triglycerides) and LCT (long chain triglycerides), exert influence on the gelation process of beeswax and thus properties of the organogel produced thereof. Organogels were produced at different temperatures and qualitative phase diagrams were constructed to identify and classify the type of structure formed at various compositions. The microstructure of gelator crystals was studied by polarized light microscopy. Melting and crystallization were characterized by differential scanning calorimetry and rheology (flow and small amplitude oscillatory measurements) to understand organogels' behaviour under different mechanical and thermal conditions. FTIR analysis was employed for a further understanding of oil-gelator chemical interactions. Results showed that the increase of beeswax concentration led to higher values of storage and loss moduli (G, G) and complex modulus (G*) of organogels, which is associated to the strong network formed between the crystalline gelator structure and the oil phase. Crystallization occurred in two steps (well evidenced for higher concentrations of gelator) during temperature decreasing. Thermal analysis showed the occurrence of hysteresis between melting and crystallization. Small angle X-ray scattering (SAXS) analysis allowed a better understanding in terms of how crystal conformations were disposed for each type of organogel. The structuring process supported by medium or long-chain triglycerides oils was an important exploit to apprehend the impact of different carbon chain-size on the gelation process and on gels' properties.

Determinación química del aceite esencial de Schinus areira L. (Aguaribay) y su actividad antioxidante.

INTRODUCCIÓN: Durante su evolución, las plantas han desarrollado un sistema químico de defensa con el fin de combatir el estrés del medio ambiente utilizando sus metabolitos secundarios. De todos los productos químicos secundarios sintetizados por las plantas, los terpenos han contribuido significativamente al desarrollo de nuevos compuestos y son producidos por una gran variedad de plantas, algunos animales (insectos y organismos marinos) y microorganismos. Son abundantes en frutas, cereales, verduras y flores, en musgos, algas y líquenes y son un componente importante de las resinas de las plantas, constituyendo uno de los grupos más amplios de fitonutrientes. Los terpenos son los principales componentes de los aceites esenciales de las plantas aromáticas y tienen gran actividad biológica y actúan como antioxidantes protegiendo los lípidos del ataque de radicales libres de especies del oxígeno, como oxígeno singlete, y radicales hidroxilo, peróxido y superóxido. OBJETIVO GENERAL. Determinar la composición química del aceite esencial de S. areira y la actividad anti-oxidante de la fracción rica en terpenos hidrocarburos y sus componentes mayoritarios, en un modelo experimental de pulmón de ratón. OBJETIVOS ESPECÍFICOS: a) Obtener el aceite esencial a partir de hojas de S. areira; b) Identificar y cuantificar los terpenos presentes en el aceite esencial de S. areira; c) Separar la fracción mayoritaria del aceite esencial (AE) (terpenos hidrocarburos); d)Detectar a nivel pulmonar los posibles efectos anti-oxidante de la administración intraperitoneal (i.p.) de la fracción de hidrocarburos obtenidas del aceite esencial de S. areira y de sus componentes mayoritarios, en un modelo inflamatorio. MATERIALES Y METODOS: 1) Obtención de las muestras de S. areira: Serán recolectada en la localidad de Mendiolaza, Córdoba. Un ejemplar de la misma será depositado en el Museo Botánico de la Fac. Cs. Ex. Fís. y Nat., UNC.2) Obtención del AE: El material vegetal será obtenido por destilación por arrastre por vapor de agua en un equipo tipo Clevenger modificado. 3) Fraccionamiento AE: Se separará la fracción mayoritaria del aceite que corresponde a la de los terpenos hidrocarburos con el fin de determinar su actividad biológica. Dicha separación se llevará a cabo por cromatografía en placa delgada (CCD) utilizando n-hexano o cloroformo como sistema de solvente para la fase móvil. También se determinará la actividad de los compuestos mayoritarios, los cuales serán obtenidos de muestras comerciales (ICN Pharmaceuticals) y para el caso de los que no estén disponibles en el comercio, serán aislados por técnicas cromatográficas. 4) Identificación y cuantificación de los terpenos del AE:Para la cuantificación de los terpenos, se realizará un análisis por cromatografía gas-liquido-espectrometría de masas (GC-MS) empleando un equipo Perkin Elmer Q600 equipado con detector de ionización de llama, con una columna capilar Elite-wax (Crossband-PEG) (60m x 0. 25 mm ID x 0. 25 µm df). La interpretación de los espectros de masas se realizará utilizando una biblioteca Adamns, NIST y por comparación con espectros similares tomados de bibliografía. 5) Inducción de inflamación con LPS y tratamiento con una fracción del AE de S. areira: Se procederá a la instilación nasal de LPS (1,67µg/Kg de peso corporal) y a las 2hs, la administración intraperitoneal de la fracción hidrocarbonada de AE (300 mg/Kg) y se determinará a las 3hs: TNF-α; infiltrado celular y dienos conjugados en muestras obtenidas en lavado bronqueo-alveolar en pulmón de ratón. 6) Genotoxidad: Se utilizará Allium cepa L. para evaluar aberraciones cromosómicas. Estadística : Se analizarán los datos con ANAVA: no paramétrico con Kruskal Wallis y Dunn a posterior (InfoStat, 2010). De los resultados se espera obtener un perfil químico de los terpenos hidrocarbonados de S. areira y evaluar su posible acción antioxidante.