Preparação e caracterização de micropartículas de polissacarídeos produzidas por secagem por atomização para libertação controlada de fármacos

Neste trabalho trabalho produziram-se micropartículas de polissacarídeos contendo um fármaco anticancerígeno, o 5-Fluorouracil, ou um anti-inflamatório, a Prednisolona, utilizando como matrizes encapsulantes o quitosano e o FucoPol. As micropartículas foram produzidas pelo método de secagem por atomização (spray-drying). Foram estudados vários reticulantes biocompatíveis: o ácido glutâmico; o ácido cítrico e a lisina. As micropartículas produzidas foram caracterizadas em termos de morfologia, tamanho, propriedades químicas, propriedades térmicas, cristalinidade e eficiência de encapsulamento recorrendo a técnicas como microscopia electrónica de varrimento (SEM), Espectro de infravermelho por transformada de Fourier (FT-IR), calorimetria diferencial de varrimento (DSC), difracção de raios-X (XRD) e espectroscopia UV. Os perfis de concentração foram obtidos realizando ensaios de libertação em dois meios distintos, em Suco Gástrico Simulado (pH=1,2) e Suco Intestinal Simulado (pH=6,8) e foram calculadas as velocidades de libertação para cada ensaio. Verificou-se que os ensaios com o fármaco modelo Prednisolona em matrizes de quitosano em meio ácido, pH=1,2, apresentam uma libertação mais lenta. Os reticulantes mais adequados para o quitosano são o ácido glutâmico para a libertação no estômago, a pH=1,2, e o ácido cítrico para a libertação no intestino, a pH=6,8. Em relação ao FucoPol, a concentração de reticulante mais adequada para ambos os meios de libertação revelou ser a de 50% em massa de lisina relativamente à massa de FucoPol.

Design and characterization of novel biopolymeric structure using biocompatible ionic liquids

The main objective of this thesis was the development of polymeric structures from the dissolution of FucoPol, a bacterial exopolysaccharide (EPS), in a biocompatible ionic liquid, choline acetate. The FucoPol was produced by the bacteria Enterobacter A47 using glycerol as carbon source at controlled temperature and pH (30ºC and 7, respectively). At the end of 3 days it was produced 7 g/L of FucoPol. The net yield of Fucopol in glycerol (YP/S) was 0.22 g/g and the maximum productivity 2.37 g/L.d This polymer was characterized about its composition in sugars and acyl groups (by High-Performance Liquid Chromatography - HPLC), containing fucose (35 % mol), galactose (21 % mol), glucose (29 % mol), rhamnose (3% mol) and glucuronic acid (12% mol) as well as acetate (14.28 % mol), pyruvate (2.15 % mol) and succinate (1.80 % mol). Its content of water and ash was 15% p/p and 2% p/p, respectively, and the chemical bonds (determined by Infrared Spectroscopy - FT-IR) are consistent to the literature reports. However, due to limitations in Differential Scanning Calorimetry (DSC) equipment it was not possible to determine the glass transition temperature. In turn, the ionic liquid showed the typical behavior of a Newtonian fluid, glass transition temperature (determined by DSC) -98.03ºC and density 1.1031 g/cm3. The study of chemical bonds by FT-IR showed that amount of water (8.80%) influenced the visualization of the bands predicted to in view of their chemical structure. After the dissolution of the FucoPol in the ionic liquid at different temperatures (50, 60, 80 and 100 ° C) it was promoted the removal of this by the phase inversion method using deionized water as a solvent, followed by drying in an oven at 70 ° C. The mixtures before and after the phase inversion method were characterized through the studies mentioned above. In order to explore possible application field’s biocompatibility assays and collage on balsa wood tests were performed. It was found that the process of washing with water by the phase inversion method was not totally effective in removing the biocompatible ionic liquid, since all FucoPol – IL mixtures still contained ionic liquid in their composition as can be seen by the DSC results and FT-IR. In addition, washing the mixtures with water significantly altered the composition of FucoPol. However, these mixtures, that developed a viscous behavior typical of a non-Newtonian fluid (shear-thinning), have the potential to be applied in the biomedical field as well as biological glues.

Valorization of olive pomace through combination of biocatalysis with supercritical fluid technology

A supercritical carbon dioxide (scCO2) based oil extraction method was implemented on olive pomace (alperujo), and an oil yield of 25,5 +/- 0,8% (goil/gdry residue) was obtained. By Soxhlet extraction with hexane, an oil extraction yield of 28,9 +/- 0,8 % was obtained, which corresponds to an efficiency of 88,4 +/- 4,8 % for the supercritical method. The scCO2 extraction process was optimized for operating conditions of 50 MPa and 348,15 K, for which an oil loading of 32,60 g oil/kg CO2 was calculated. As a proof of concept, olive pomace was used as feedstock for biodiesel production, in a process combining the use of lipase as a catalyst with the use of scCO2 as a solvent, and integrating the steps of oil extraction, oil to biodiesel transesterification and subsequent separation of the latter. In the conducted experiments, FAME (fatty acid methyl ester) purities of 90% were obtained, with the following operating parameters: an oil:methanol molar ratio of 1:24; a residence time of 7,33 and 11,6 mins; a pressure of 40 MPa; a temperature of 313,15 K; and Lipozyme (Mucor miehei; Sigma-Aldritch) as an enzyme. However, oscillations of FAME purity were registered throughout the experiments, which could possibly be due to methanol accumulation in the enzymatic reactor. Finally, the phenolic content of olive pomace, and the effect of the drying process – oven or freeze-drying – and the extraction methods – hydro-alcoholic method and supercritical method – on the phenolic content were analysed. It was verified that the oven-drying process on the olive pomace preserved 90,1 +/- 3,6 % of the total phenolic content. About 62,3 +/- 5,53% of the oven-dried pomace phenolic content was extracted using scCO2 at 60 MPa and 323,15 K. Seven individual phenols – hydroxytyrosol, tyrosol, oleuropein, quercetin, caffeic acid, ferulic acid and p-coumaric acid – were identified and quantified by HPLC.

Cellulose-based composites as functional conductive materials for printed electronics

In this work, cellulose-based electro and ionic conductive composites were developed for application in cellulose based printed electronics. Electroconductive inks were successfully formulated for screen-printing using carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) as conductive functional material and cellulose derivatives working as binder. The formulated inks were used to fabricate conductive flexible and disposable electrodes on paper-based substrates. Interesting results were obtained after 10 printing passes and drying at RT of the ink with 10 % wt. of pristine CFs and 3% wt. of carboxymethyl cellulose (CMC), exhibiting a resistivity of 1.03 Ωcm and a resolution of 400 μm. Also, a resistivity of 0.57 Ωcm was obtained for only one printing pass using an ink based on 0.5 % wt. MWCNTs and 3 % wt. CMC. It was also demonstrated that ionic conductive cellulose matrix hydrogel can be used in electrolyte-gated transistors (EGTs). The electrolytes revealed a double layer capacitance of 12.10 μFcm-2 and ionic conductivity of 3.56x10-7 Scm-1. EGTs with a planar configuration, using sputtered GIZO as semiconducting layer, reached an ON/OFF ratio of 3.47x105, a VON of 0.2 V and a charge carrier mobility of 2.32 cm2V-1s-1.

Characterization of earth-based mortars for rammed earth repair

All over the world, many earth buildings are deteriorating due to lack of maintenance and repair. Repairs on rammed earth walls are mainly done with mortars, by rendering application; however, often the repair is inadequate, resorting to the use of incompatible materials, including cement-based mortars. It has been observed that such interventions, in walls that until that day only had presented natural ageing issues, created new problems, much more dangerous for the building than the previous ones, causing serious deficiencies in this type of construction. One of the problems is that the detachment of the new cement-based mortar rendering only occurs after some time but, until that occurrence, degradations develop in the wall itself. When the render detaches, instead of needing only a new render, the surface has to be repaired in depth, with a repair mortar. Consequently, it has been stablished that the renders, and particularly repair mortars, should have physical, mechanical and chemical properties similar to those of the rammed earth walls. This article intends to contribute to a better knowledge of earth-based mortars used to repair the surface of rammed earth walls. The studied mortars are based on four types of earth: three of them were collected from non-deteriorated parts of walls of unstabilized rammed earth buildings located in Alentejo region, south of Portugal; the fourth is a commercial earth, consisting mainly of clay. Other components were also used, particularly: sand to control shrinkage; binders stabilizers such as dry hydrated air-lime, natural hydraulic lime, Portland cement and natural cement; as well as natural vegetal fibers (hemp fibers). The experimental analysis of the mortars in the fresh state consisted in determining the consistency by flow table and the bulk density. In the hardened state, the tests made it possible to evaluate the following properties: linear and volumetric shrinkage; capillary water absorption; drying capacity; dynamic modulus of elasticity; flexural and compressive strength.

Optimization of wastewater quality in the Sines refinery

In order to address and resolve the wastewater contamination problem of the Sines refinery with the main objective of optimizing the quality of this stream and reducing the costs charged to the refinery, a dynamic mass balance was developed nd implemented for ammonia and polar oil and grease (O&G) contamination in the wastewater circuit. The inadequate routing of sour gas from the sour water stripping unit and the kerosene caustic washing unit, were identified respectively as the major source of ammonia and polar substances present in the industrial wastewater effluent. For the O&G content, a predictive model was developed for the kerosene caustic washing unit, following the Projection to Latent Structures (PLS) approach. Comparison between analytical data for ammonia and polar O&G concentrations in refinery wastewater originating from the Dissolved Air Flotation (DAF) effluent and the model predictions of the dynamic mass balance calculations are in a very good agreement and highlights the dominant impact of the identified streams for the wastewater contamination levels. The ammonia contamination problem was solved by rerouting the sour gas through an existing clogged line with ammonia salts due to a non-insulated line section, while for the O&G a dynamic mass balance was implemented as an online tool, which allows for prevision of possible contamination situations and taking the required preventive actions, and can also serve as a basis for establishing relationships between the O&G contamination in the refinery wastewater with the properties of the refined crude oils and the process operating conditions. The PLS model developed could be of great asset in both optimizing the existing and designing new refinery wastewater treatment units or reuse schemes. In order to find a possible treatment solution for the spent caustic problem, an on-site pilot plant experiments for NaOH recovery from the refinery kerosene caustic washing unit effluent using an alkaline-resistant nanofiltration (NF) polymeric membrane were performed in order to evaluate its applicability for treating these highly alkaline and contaminated streams. For a constant operating pressure and temperature and adequate operating conditions, 99.9% of oil and grease rejection and 97.7% of chemical oxygen demand (COD) rejection were observed. No noticeable membrane fouling or flux decrease were registered until a volume concentration factor of 3. These results allow for NF permeate reuse instead of fresh caustic and for significant reduction of the wastewater contamination, which can result in savings of 1.5 M€ per year at the current prices for the largest Portuguese oil refinery. The capital investments needed for implementation of the required NF membrane system are less than 10% of those associated with the traditional wet air oxidation solution of the spent caustic problem. The operating costs are very similar, but can be less than half if reusing the NF concentrate in refinery pH control applications. The payback period was estimated to be 1.1 years. Overall, the pilot plant experimental results obtained and the process economic evaluation data indicate a very competitive solution through the proposed NF treatment process, which represents a highly promising alternative to conventional and existing spent caustic treatment units.

Determination of fat soluble vitamins from amazonian fresh-water fishes. I. HPLC analysis of tambaqui, pirarucu and cuiu-cuiu livers .

It was found that fish livers from the Amazon have considerable amounts of vitamins A, D and E compared with the values of the standartized cod-liver oil. Tambaqui liver oil has high concentration of vitamin A1(retinol) and vitamin A2 (degidroretinol) whereas the liver oils of pirarucu and cuiu-cuiu have preferently the vitamin A2. The contents of the vitamins D and E observed in the liver oils of tambaqui and cuiu-cuiu was extremely high.

Natural hydraulic lime (nhl3.5) mortars with scrap tire rubber

The use of wastes and industrial by-products as building materials is an important issue in order to decrease costs with waste management and the embodied energy of building products. In this study scrap tire rubber was used as additional aggregate of mortars based on natural hydraulic lime NHL 3.5 and natural sand. Different particle size fractions and proportions of scrap tire rubber were used: a mix obtained directly from industry and separated fine, medium and coarse fractions; 0 %, 18 %, 36 % and 54 % of the weight of binder, corresponding to 2.5 %, 5 % and 7.5 % of the weight of sand. As mortars based on NHL specifications became stricter with the current version of EN 459–1:2015, the influence of the rubber’s additions on the mortars’ fresh state, mechanical and physical performance is presented in this work: flow table consistency, water retention, dynamic elasticity modulus, flexural and compressive strength, open porosity and bulk density, capillary absorption, drying and thermal conductivity are studied. The use of the rubber mix coming from the waste tire industry seems advantageous and may open possibilities for use as raw material by the mortars industry.

ESSENTIAL OIL OF Protium unifoliolatum (BURSERACEAE)

The major constituents of the leaf essential oil of P. unifoliolatumare trans-caryophyllene (37.45%), limonene (24.23%) and α-humulene (9.94%).

Sesquiterpenes of Amazonian Piper species*

The essential oils from leaves and thin branches of Piper amapense, Piper ducket and Piper bartlingianum were analysed by GC/MS and all volatile compounds were identified as sesquiterpenes. The main constitutents identified in the oil of P. amapense were trans-caryophyllene (25.0%), caryophyllene oxide (17.0%) and β-selinene (15.0%). The oil of P. duckei was dominated by trans-caryophyllene (23.5%), caryophyllene oxide (18.4%), β-eudesmol (9.4%) and a-eudesmol (9.1%). The major components found in the oil of P. bartlingianum were

Acellular Gellan-gum based bilayered structures for the regeneration of osteochondral defects: a preclinical study

 In orthopaedics, the management and treatment of osteochondral (OC) defects remains an ongoing clinical challenge. Autologous osteochondral mosaicplasty has been used as a valid option for OC treatments although donor site morbidity remains a source of concern [1]. Engineering a whole structure capable of mimicking different tissues (cartilage and subchondral bone) in an integrated manner could be a possible approach to regenerate OC defects. In our group we have been proposing the use of bilayered structures to regenerate osteochondral defects [2,3]. The present study aims to investigate the pre-clinical performance of bilayered hydrogels and spongy-like hydrogels in in vivo  models (mice and rabbit, respectively), in both subcutaneous and orthotopic models. The bilayered structures were produced from Low Acyl Gellan Gum (LAGG) from Sigma-Aldrich, USA. Cartilage-like layers were obtained from a 2wt% LAGG solution. The bone-like layers were made of 2wt% LAGG with incorporation of hydroxyapatite at 20% and 30% (w/v). Hydrogels and spongy-like were subcutaneouly implanted in mice to evaluate the inflammatory response. Then, OC defects were induced in rabbit knee to create a critical size defect (4 mm diameter and 5 mm depth), and then hydrogels and sponges implanted. Both structures followed different processing methods. The hydrogels were injected allowing in situ  crosslinking. Unlike, the spongy-like were pre-formed by freeze-drying. The studies concerning subcutaneous implantation and critical size OC defect were performed for 2 and 4 weeks time, respectively. Cellular behavior and inflammatory responses were assessed by means of histology staining and biochemical function and matrix deposition by immunohistochemistry. Additionally, both OC structures stability and new cartilage and bone formation were evaluated by using vivo- computed tomography (Scanco 80). The results showed no acute inflammatory response for both approaches. New tissue formation and integration in the adjacent tissues were also observed, which present different characteristic behaviors when comparing hydrogels and sponges response. As future insights, a novel strategy for regeneration of OC defects can be designed encompassing both, hydrogels and spongy-like structures and cellular approaches. References: 1. Espregueira-Mendes J. et al. Osteochondral transplantation using autografts from the upper tibio-fibular joint for the treatment of knee cartilage lesions. Knee Surgery, Sports Traumatology, Arthroscopy 20,1136, 2012. 2. Oliveira JM. et al, Novel hydroxyapatite/chitosan bilayered scaffold for osteochondral tissue-engineering applications: Scaffold design and its performance when seeded with goat bone marrow stromal cells. Biomaterials 27, 6123, 2006. 3. Pereira D R. et al. Gellan Gum-Based Hydrogel Bilayered Scaffolds for Osteochondral Tissue Engineering. Key Engineering Materials 587, 255, 2013.

Saloplastic membranes as green devices for soft tissue regeneration

Implantable devices must exhibit mechanical properties similar to native tissues to promote appropriate cellular behavior and regeneration. Herein, we report a new membrane manufacture method based on the synthesis of polyelectrolyte complexes (PECs) that exhibit saloplasticity, i.e. variable physical-chemistry using salt as a plasticizer. This is a Green Chemistry approach, as PECs generate structures that are stabilized solely by reversible electrostatic interactions, avoiding the use of harmful crosslinkers completely. Furthermore, natural polyelectrolytes - chitosan and alginate - were used. Upon mixing them, membranes were obtained by drying the PECs at 37ºC, yielding compact PECs without resorting to organicsolvents. The plasticizing effect of salt after synthesis was shown by measuring tensile mechanical properties, which were lower when samples were immersed in high ionic strength solutions.Salt was also used during membrane synthesis in different quan- tities (0 M, 0.15 M and 0.5 M in NaCl) yielding structures with no significant differences in morphology and degradation (around 15% after 3 months in lysozyme). However, swelling was higher (about 10x) when synthesized in the presence of salt. In vitro cell studies using L929 fibroblasts showed that cells adhered and proliferated preferentially in membranes fabricated in the presence of salt (i.e. the membranes with lower tensile strength). Structures with physical-chemical properties controlled with precision open a path to tissue engineering strategies depending on fine tuning mechanical properties and cellular adhesion simply by changing ionic strength during membrane manufacture

Assessing the feasibility of impregnating phase change materials in lightweight aggregate for development of thermal energy storage systems

This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed that, the impregnation/encasement method is effective with respect to the large thermal energy storage density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt road pavements.

Moisture-induced degradation of interfacial bond in FRP-strengthened masonry

Externally bonded strengthening of masonry structures using Fiber Reinforced Polymers (FRPs) has been accepted as a promising technique. Although the effectiveness of FRPs in improving the performance of masonry components has been extensively investigated, their long-term performance and durability remain poorly addressed. This paper, tackling one of the aspects related to durability of these systems, presents an experimental investigation on the effect of long-term (one year) water immersion on the performance of GFRP-strengthened bricks. The tests include materials' mechanical tests, as well as pull-off and single-lap shear bond tests, to investigate the changes in material properties and bond behavior with immersion time, respectively. The effect of mechanical surface treatment on the durability of the strengthened system as well as the reversibility of the degradation upon partial drying are also investigated. The experimental results are presented and critically discussed.

Ancient materials and techniques to improve the earthen building durability

A substantial part of the world building heritage has been performed by earthen building. The durability of this existing heritage and mainly of the new buildings built with earth is particularly conditioned by the erosion caused by water action, especially in countries with high levels of rainfall. This research aims to contribute to the increase of knowledge about the ancient building techniques that provide enhanced durability. It is possible to analyse the ancestral practices used to protect the earth material from the water action in order to understand how the old earthen buildings were preserved over the centuries, resisting to harsh weather conditions. Among these techniques are: the incorporation of biopolymers (such as oils or fats from animal or vegetable origin); the addition of some minerals; and the earth stabilization with lime. However, this knowledge seems to be forgotten, probably due to the prejudice related to earthen constructions, which several times are associated with a poor building. This research also focuses on the study of new methods of earth stabilization with lime and biopolymers, adapting the ancient knowledge to improve the durability related to the water action. Therefore, alternative solutions can be obtained to improve the performance of earthen buildings, mainly the resistance of the material in the presence of water, reducing its permeability to water. In addition, with the proposed solutions it is possible to obtain good levels of water vapour permeability, one of the major advantages of the construction with earth.