Riesz potential operators and inverses via fractional centred derivatives

International Journal of Mathematics and Mathematical Sciences, Vol.2006

Designing market-based instruments for biodiversity conservation: learning with the Australian experience and evaluating Portugal's potential

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia do Ambiente, perfil Gestão de Sistemas Ambientais

The International Multilateral System: Imperatives of Change, Potential Scenarios and Suggestions for the Future

Thesis presented to satisfy the necessary requirements for obtaining a PhD degree in International Relation with specialization in Globalization and the Environment,

Selective synthesis under microwave irradiation of new monomers for potential applications in PDLC films

Dissertation to obtain the degree of master in Bioorganic

Host-induced changes in the cell surface N-linked glycoproteins, from Aspergillus fumigatus. Search for specific targets with potential for clinical therapy and/or diagnosis.

This dissertation is presented to obtain a Master degree in Structural and Functional Biochemistry

Aquaponics and its potential aquaculture wastewater treatment and human urine treatment

The main objective of this thesis is to study the developing fields of aquaponics and its potential for aquaculture wastewater treatment and human urine treatment. Aquaponics is a food production system which combines fish farming (aquaculture) with soilless crop farming (hydroponics). In this thesis the concept of aquaponics and the underlying processes are explained. Research on aquaculture wastewater and human urine wastewater is reviewed and its potential application with aquaponic systems is studied. An overview of the different types of aquaponic systems and current research on the field is also presented. A case study was conducted in a farm in Askeröd, Sweden, which involved building two aquaponic systems (System 1 and System 2) and a human urine-based aquaponic system (System 3), with different degrees of component complexity and sizes. The design, building and monitoring of System 1, System 2 and System 3 was documented and described in detail. Four day experiments were conducted which tested the evolution in concentration of Total Ammonia Nitrogen (NH4+/NH3), Nitrite (NO2-), Nitrate (NO3-), Phosphate (PO43-), and Dissolved Oxygen (O2) after an initial nutrient input. The goal was to assess the concentrations of these parameters after four days and compare them with relevant literature examples in the aquaculture industry and in source-separated urine research. Neither of the two aquaponic systems (System 1 and System 2) displayed all of the parameter concentrations in the last day of testing below reference values found in literature. The best performing of the aquaponic systems was the more complex system (System 2) combining the hydroponic Nutrient Film Technique with a Deep Water Culture component, with a Total Ammonia Nitrogen concentration of 0,20 mg/L, a Nitrite concentration of 0,05 mg/L, a Nitrate concentration of 1,00-5,00 mg/L, a Phosphate concentration of <0,02 mg/L and a Dissolved Oxygen concentration of 8,00 mg/L. The human urine-based aquaponic system (System 3) underperformed in achieving the reference concentration values in literature for most parameters. The removal percentage between the higher recorded values after the input addition and the final day of testing was calculated for two literature examples of separated urine treatment and System 3. The system had a removal percentage of 75% for Total Ammonia Nitrogen, 98% for Nitrite, 25% for Nitrate and 50% for Phosphate. These percentages still underperformed literature examples in most of the tested parameters. The results gathered allowed to conclude that while aquaculture wastewater treatment and human urine treatment is possible with aquaponics systems, overall these did not perform as well as some examples found in recirculating aquaculture systems and source-separated urine treatment literature. However, better measuring techniques, longer testing periods and more research is recommended in this field in order to draw an improved representative conclusion.

Double-walled PLLA/PLGA particles for the sustained release of Meloxicam: preparation, characterisation and contolled release studies

There were two main objectives in this thesis investigation, first, the production, characterisation, in vitro degradation and release studies of double walled microspheres for drug release control. The second one, and the most challenging, was the production of double walled nanospheres, also for drug control delivery. The spheres were produced using two polymers, the Poly(L-lactide)Acid, PLLA, and the Poly(L-lactide-co-glycolic)Acid, PLGA.Afterwards, a model drug, Meloxicam, which is an antiinflammatory drug, was encapsulated into the particles. Micro and nanospheres were produced by the solvent extraction/evaporation method, where perfect spherical particles were obtained. By varying the polymers PLLA/PLGA mass ratio, different core and shell composition, as well as several shell and core thickness were observed. In the particles with a PLLA/PLGA mass ratio 1:1, the shell is composed by PLLA and the core by PLGA. It was also verified that the Meloxicam has a tendency to be distributed in the PLGA layer. Micro and nanoparticles were characterised in morphology, size, polymer cristalinity properties and drug distribution. Particles degradation studies was performed, where the particles in a PVA solution of pH 7,4 where placed in an incubator, during approximately 40 days, at 120rpm, and 37ºC, simulating, as much as possible, the human body environment. From these studies, the conclusion was that particles containing a PLGA shell and a PLLA core degrade more rapidly, due to the fact that PLLA is more hydrophobic than the PLGA. Concerning the drug release controlled results, done also for 40 and 50 days, they showed that the microspheres containing a shell of PLLA release more slowly than when the shell is composed of PLGA. This result was predictable, since the drug is solubilised in the PLGA polymer and so, in that case, the PLLA shell works like a barrier between the drug and the outer medium. Another positive aspect presented by this study is the lower initial burst effect, obtained when using double walled particles, which is one of the advantages of the same. In a second part of this investigation, the production of the nanospheres was the main goal, since it was not yet accomplished by other authors or investigators. After several studies, referring to the speed, time and type of agitation, as well as, the concentration and volume of the first aqueous solution of poly-vinyl-alcohol (PVA) during the process of solvent extraction/evaporation it was possible to obtain double walled nanospheres.(...)

Earthen plasters: the potential of the clayey soils of barrocal region in Algarve

Due to their high adsorption capacity of water vapor, earthen plasters can act as a moisture buffer, contributing to balance the relative humidity of the indoor environment of buildings. As a consequence of this capacity earthen plasters may also contribute to the perception of thermal comfort, since a high relative humidity increases the thermal conductivity of air and restricts skin evaporation, increasing the discomfort associated with the perception of heat or cold. Simultaneously, earthen plasters may also contribute to the indoor air quality. In one hand, by mitigating health problems of the respiratory system associated with indoor environment with high relative humidity, in which increases the risk of development of microorganisms usually responsible for infections, allergies or asthma. In the other hand, by mitigating the probability of inflammation of the respiratory system airways associated to exceedingly dry indoor environments. Therefore it also becomes expectable that earthen plasters may contribute for reducing the needs for air conditioning and mechanical ventilation in buildings and, thereby, also allowing the reduction of the associated energy consumption. The «Barrocal» region, located in the sedimentary basin of Algarve, South Portugal, presents geomorphological characteristics that promote the occurrence of soils with a clay mineralogy dominated by illite, which is a clay mineral characterized by a high adsorption capacity of water vapor and low expansibility. This fact turns expectable that these soils have a high potential for interior plastering. In order to evaluate this potential four mortars were formulated with an increasing content of clayey soil extracted from a selected clay quarry from «Barrocal» region. The results from the preliminary characterization campaign confirmed the reduced linear shrinkage of these mortars, as well as their high adsorption-desorption capacity, that is positively correlated with the content of clayey soil present in mortar formulation. However, the mechanical tests showed that the mechanical resistance of these mortars should be improved, for instance through the addition of natural fibers for reinforcement, which will be investigated in future research. This research contributed to increase certainty regarding the potential of clayey soils of the «Barrocal» sub-region of Algarve to produce mortars suitable for eco-efficient interior plastering.

Groundwater quality, vulnerability and potential assessment in Kobo Valley development project, Ethiopia

This study deals with investigating the groundwater quality for irrigation purpose, the vulnerability of the aquifer system to pollution and also the aquifer potential for sustainable water resources development in Kobo Valley development project. The groundwater quality is evaluated up on predicting the best possible distribution of hydrogeochemicals using geostatistical method and comparing them with the water quality guidelines given for the purpose of irrigation. The hydro geochemical parameters considered are SAR, EC, TDS, Cl-, Na+, Ca++, SO4 2- and HCO3 -. The spatial variability map reveals that these parameters falls under safe, moderate and severe or increasing problems. In order to present it clearly, the aggregated Water Quality Index (WQI) map is constructed using Weighted Arithmetic Mean method. It is found that Kobo-Gerbi sub basin is suffered from bad water quality for the irrigation purpose. Waja Golesha sub-basin has moderate and Hormat Golena is the better sub basin in terms of water quality. The groundwater vulnerability assessment of the study area is made using the GOD rating system. It is found that the whole area is experiencing moderate to high risk of vulnerability and it is a good warning for proper management of the resource. The high risks of vulnerability are noticed in Hormat Golena and Waja Golesha sub basins. The aquifer potential of the study area is obtained using weighted overlay analysis and 73.3% of the total area is a good site for future water well development. The rest 26.7% of the area is not considered as a good site for spotting groundwater wells. Most of this area fall under Kobo-Gerbi sub basin.

Firms survival and international trade: The impact of exports and imports

Double Degree. A Work Project presented as part of the requirements for the Award of a Masters in Management from Nova School of Business and Economics and Maastricht University.

The financial system in Mozambique: Opportunities, barriers and market potential

This research is empirical and exploratory intending to analyse the attractiveness of banking in Mozambique, considering its positive outlook. To identify the opportunities and barriers, the methods adopted were elite interviews with banking executives, complemented by secondary data. The opportunities for new entrants seem to include bankarization and the emergence of micro and smallmedium enterprises; other avenues seem to include investment banking, support of mega-projects (e.g. energy, infrastructures) through syndicates and cooperation with multilaterals, and the participation in developing capital markets. Conversely, the main barriers include shortage of talent, inadequate infrastructures, poverty, unsophisticated entrepreneurial culture (e.g. informal economy, inadequate financial reporting), burdensome bureaucracy (e.g. visas), foreign exchange regulation, as well as low liquidity and high funding costs for banks. The key conclusions suggest a window of opportunity for niche markets, and new products and services in retail and investment banking.

Assessment of a novel Cu (II) complex as a potential anticancer agent

Widely used in cancer treatment, chemotherapy still faces hindering challenges, ranging from severe induced toxicity to drug resistance acquisition. As means to overcome these setbacks, newly synthetized compounds have recently come into play with the basis of improved pharmacokinetic/pharmacodynamic properties. With this mind-set, this project aimed towards the antiproliferative potential characterization of a group of metallic compounds. Additionally the incorporation of the compounds within a nanoformulation and within new combination strategies with commercial chemotherapeutic drugs was also envisaged. Cell viability assays presented copper (II) compound (K4) as the most promising, presenting an IC50 of 6.10 μM and 19.09 μM for HCT116 and A549 cell line respectively. Exposure in fibroblasts revealed a 9.18 μM IC50. Hoechst staining assays further revealed the compound’s predisposition to induce chromatin condensation and nuclear fragmentation in HCT116 upon exposure to K4 which was later demonstrated by flow cytometry and annexin V-FITC/propidium iodide double staining analysis (under 50 % cell death induction). The compound further revealed the ability to interact with major macromolecules such as DNA (Kb = 2.17x105 M-1), inducing structural brakes and retardation, and further affecting cell cycle progression revealing delay in S-phase. Moreover BSA interactions were also visible however not conclusive. Proteome profiling revealed overexpression of proteins involved in metabolic activity and underexpression of proteins involved in apoptosis thus corroborating Hoechst and apoptosis flow cytometry data. K4 nanoformulation suffered from several hindrances and was ill succeeded in part due to K4’s poor solubility in aqueous buffers. Other approaches were considered in this regard. Combined chemotherapy assays revealed high cytotoxicity for afatinib and lapatinib strategies. Lapatinib and K4 proteome profiling further revealed high apoptosis rates, high metabolic activity and activation of redundant proteins as part of compensatory mechanisms.