Improved polymeric medical devices for active substances delivery

The work presented in this thesis was developed in collaboration with a Portuguese company, BeyonDevices, devoted to pharmaceutical packaging, medical technology and device industry. Specifically, the composition impact and surface modification of two polymeric medical devices from the company were studied: inhalers and vaginal applicators. The polyethylene-based vaginal applicator was modified using supercritical fluid technology to acquire self-cleaning properties and prevent the transport of bacteria and yeasts to vaginal flora. For that, in-situ polymerization of 2-substituted oxazolines was performed within the polyethylene matrix using supercritical carbon dioxide. The cationic ring-opening polymerization process was followed by end-capping with N,N-dimethyldodecylamine. Furthermore, for the same propose, the polyethylene matrix was impregnated with lavender oil in supercritical medium. The obtained materials were characterized physical and morphologically and the antimicrobial activity against bacteria and yeasts was accessed. Materials modified using 2-substituted oxazolines showed an effective killing ability for all the tested microorganisms, while the materials modified with lavender oil did not show antimicrobial activity. Only materials modified with oligo(2-ethyl-2-oxazoline) maintain the activity during the long term stability. Furthermore, the cytotoxicity of the materials was tested, confirming their biocompatibilty. Regarding the inhaler, its surface was modified in order to improve powder flowability and consequently, to reduce powder retention in the inhaler´s nozzle. New dry powder inhalers (DPIs), with different needle’s diameters, were evaluated in terms of internal resistance and uniformity of the emitted dose. It was observed that they present a mean resistance of 0.06 cmH2O0.5/(L/min) and the maximum emitted dose obtained was 68.9% for the inhaler with higher needle´s diameter (2 mm). Thus, this inhaler was used as a test and modified by the coating with a commonly-used force control agent, magnesium stearate, dried with supercritical carbon dioxide (scCO2) and the uniformity of delivered dose tests were repeated. The modified inhaler showed an increase in emitted dose from 68.9% to 71.3% for lactose and from 30.0% to 33.7% for Foradil.

FPGA field oriented control of an axial flux motor-in-wheel

This paper presents the design and the prototype implementation of a three-phase power inverter developed to drive a motor-in-wheel. The control system is implemented in a FPGA (Field Programmable Gate Array) device. The paper describes the Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique that were implemented. The control platform uses a Spartan-3E FPGA board, programmed with Verilog language. Simulation and experimental results are presented to validate the developed system operation under different load conditions. Finally are presented conclusions based on the experimental results.

Field oriented control of an axial flux permanent magnet synchronous motor for traction solutions

Electric Vehicles (EVs) are increasingly used nowadays, and different powertrain solutions can be adopted. This paper describes the control system of an axial flux Permanent Magnet Synchronous Motor (PMSM) for EVs powertrain. It is described the implemented Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique. Also, the mathematical model of the PMSM is presented. Both, simulation and experimental, results with different types of mechanical load are presented. The experimental results were obtained using a laboratory test bench. The obtained results are discussed.

Predictive control of a current-source inverter for solar photovoltaic grid interface

Solar photovoltaic systems are an increasing option for electricity production, since they produce electrical energy from a clean renewable energy resource, and over the years, as a result of the research, their efficiency has been increasing. For the interface between the dc photovoltaic solar array and the ac electrical grid is necessary the use of an inverter (dc-ac converter), which should be optimized to extract the maximum power from the photovoltaic solar array. In this paper is presented a solution based on a current-source inverter (CSI) using continuous control set model predictive control (CCS-MPC). All the power circuits and respective control systems are described in detail along the paper and were tested and validated performing computer simulations. The paper shows the simulation results and are drawn several conclusions.

Control of bovine mastitis: old and recent therapeutic approaches

Mastitis is defined as the inflammatory response resulting of the infection of the udder tissue and it is reported in numerous species, namely in domestic dairy animals. This pathology is the most frequent disease of dairy cattle and can be potentially fatal. Mastitis is an economically important pathology associated with reduced milk production, changes in milk composition and quality, being considered one of the most costly to dairy industry. Therefore, the majority of research in the field has focused on control of bovine mastitis and many efforts are being made for the development of new and effective anti-mastitis drugs. Antibiotic treatment is an established component of mastitis control programs; however, the continuous search for new therapeutic alternatives, effective in the control and treatment of bovine mastitis, is urgent. This review will provide an overview of some conventional and emerging approaches in the management of bovine mastitis infections.

Patrones dinámicos de abundancia y dispersión de una plaga en un paisaje heterogéneo. Dynamic patterns of abundance and dispersion of a pest in a heterogeneous landscape.

El desarrollo de conocimiento empírico sobre cómo la heterogeneidad espacial de un paisaje afecta los patrones de movimiento de una especie animal es considerado una prioridad para el manejo y la conservación de las especies y sus hábitats. En el caso de los insectos plaga, estos estudios resultan importantes ya que aportan las bases teóricas y empíricas fundamentales para su manejo. La persistencia de éstas especies en un paisaje modificado depende de la interrelación entre procesos ecológicos y la estructura del paisaje, tales como la interacción entre especies, la disponibilidad de parches hábitat y la influencia de las prácticas de manejo. El análisis de éstos procesos en un agroecosistema permite simplificar los modelos de heterogeneidad espacial, debido a que los lotes de cultivo son internamente homogéneos y los disturbios antropogénicos generalmente ocurren a la escala de parche, permitiendo determinar las respuestas de los insectos a dicha escala. La alfalfa (Medicago sativa) es un recurso fundamental para la producción agropecuaria y en Argentina, es el recurso forrajero más importante, constituyendo la base de la producción ganadera del país. Actualmente se cultivan alrededor de 5 millones de hectáreas, de las cuales un millón se siembran en la provincia de Córdoba. Además, cumple un rol importante en la sustentabilidad de los sistemas de producción por su función de recuperación de la fertilidad y estabilidad edáfica. La isoca de la alfalfa (Colias lesbia) es la plaga principal del cultivo, produciendo en promedio la pérdida de un corte por año. La hipótesis principal de nuestro trabajo es que los patrones de abundancia y movilidad de la isoca de la alfalfa son afectados por la estructura del paisaje y las prácticas de manejo. Los objetivos específicos del proyecto son: (a) Establecer el efecto de la estructura del paisaje y y el manejo del cultivo en la abundancia de los distintos estadios de Colias lesbia. (b) Determinar los patrones de dispersión de Colias lesbia en relación a la heterogeneidad espacial del paisaje (c) Generar un modelo predictivo de la abundancia de Colias lesbia según la estructura espacial del paisaje, el clima y el manejo del cultivo. (d) Desarrollar un conjunto de recomendaciones de manejo a escala regional para el control de la isoca de la alfalfa. Para ello se elegirán lotes de alfalfa en la región este de la provincia de Córdoba, en el departamento de San Justo, donde se realizará un relevamiento inicial del área de estudio y se dialogará con los productores. Paralelamente, se realizará una clasificación supervisada del área de estudio a partir de escenas de imágenes Landsat TM. En los parches seleccionados, durante 3 años y durante los meses de verano, se muestrearán quincenalmente los distintos estadios de Colias lesbia. Se realizarán análisis de correlación y regresión entre las variables independientes (métricas de la configuración y dinámica del paisaje) y las variables dependientes, (abundancia media de los diferentes estadios de las poblaciones). Asimismo, se realizarán experimentos de marcado-liberación-recaptura para determinar cómo el movimiento de la especie depende de la estructura del paisaje. Para modelar el movimiento inherente de la especie se combinará la información obtenida en el campo con un modelo de difusión utilizando métodos bayesianos. Se espera obtener modelos que permitan comprender los mecanismos que generan los patrones observados. Con esta información se propondrán lineamientos generales y específicos para un manejo de la isoca de la alfalfa a escala regional. En tal sentido, se espera aportar información para restringir la dispersión de la plaga, y reducir los costos y perjuicios del control químico que podrían evitarse con la aplicación de prácticas de manejo integrado y de "manejo de área" que minimicen el impacto de la plaga como también contribuir al conocimiento general de la ecología de insectos.

A comparison of environmental licensing systems in operation in the wood panel manufacturing industry in the Northern Hemisphere

The objective of this thesis is to compare and contrast environmental licensing systems, for the wood panel industry, in a number of countries in order to determine which system is the best from an environmental and economic point of view. The thesis also examines the impact which government can have on industry and the type of licensing system in operation in a country. Initially, the thesis investigates the origins of the various environmental licensing systems which are in operation in Ireland, Scotland, Wales, France, USA and Canada. It then examines the Environmental Agencies which control and supervise industry in these countries. The impact which the type of government (i.e. unitary or federal) in charge in any particular country has on industry and the Regulatory Agency in that country is then described. Most of the mills in the thesis make a product called OSB (Oriented Strand Board) and the manufacturing process is briefly described in order to understand where the various emissions are generated. The main body of the thesis examines a number of environmental parameters which have emission limit values in the licenses examined, although not all of these parameters have emission limit values in all of the licenses. All of these parameters are used as indicators of the potential impact which the mill can have on the environment. They have been set at specific levels by the Environmental Agencies in the individual countries to control the impact of the mill. Following on from this, the two main types of air pollution control equipment (WESPs and RTOs) are described in regard to their function and capabilities. The mill licenses are then presented in the form of results tables which compare air results and water results separately. This is due to the fact that the most significant emission from this type of industry is to air. A matrix system is used to compare the licenses so that the comparison can be as objective as possible. The discussion examines all of the elements previously described and from this it was concluded that the IPC licensing system is the best from an environmental and economic point of view. It is a much more expensive system to operate than the other systems examined, but it is much more comprehensive and looks at the mill as a whole rather than fragmenting it. It was also seen that the type of environmental licensing system which is in place in a country can play a role in the locating of an industry as certain systems were seen to have more stringent standards attached to them. The type of standard in place in a country is in turn influenced by the type of government which is in place in that country.

Artificial diets for the production of natural enemies (predators and parasitoids) of greenhouse pest insects

The aim of this contract was to finalise in vitro rearing on artificial diets of entomophagous insects useful to control insect pests mainly in greenhouses through an analytical and rational approach. The work focuses on the development and optimisation of artificial diets for one coccinellid (Harmonia axyridis), two heteropteran predators (Orius laevigatus, Dicyphus tamaninii), and a braconid parasitoid of aphids (Aphidius ervi). The definition of the artificial diets was based on biochemical analyses of their natural food (aphids) or substitution food for the predators (Ephestia kuehniella eggs). Reliable quality control parameters of the entomophages produced were used in order to adjust dietary composition and formulation of the different diets tested.

How much does industry matter in an emerging market economy?

Theories of firm profitability make different predictions about the relative importance of firm, industry and time specific factors. We assess, empirically, the relevance of these effects over a sixteen year period in India, as a regime of control and regulation, pre 1985, gave way to partial liberalisation between 1985 and 1991 and to more decisive liberalisation after 1991. We find that firm effects are important throughout, when rent seeking opportunities proliferated, as well as when competitive forces were enhanced by institutional change. In contrast, industry effects significantly increased after liberalisation, suggesting that industry structure matters more within competitive markets. These findings help understand the relevance of different models over different stages of liberalisation, and have important implications for both theory and policy.

Oral insecticidal activity of root colonizing Pseudomonas fluorescens CHA0: a biocontrol agent with potential to control plant pests and diseases

The application of microbial biocontrol agents for the control of fungal plant diseases and plant insect pests is a promising approach in the development of environmentally benign pest management strategies. The ideal biocontrol organism would be a bacterium or a fungus with activity against both, insect pests and fungal pathogens. Here we demonstrate the oral insecticidal activity of the root colonizing Pseudomonas fluorescens CHA0, which is so far known for its capacity to efficiently suppress fungal plant pathogens. Feeding assays with CHA0-sprayed leaves showed that this strain displays oral insecticidal activity and is able to efficiently kill larvae of three important insect pests. We further show data indicating that the Fit insect toxin produced by CHA0 and also metabolites controlled by the global regulator GacA contribute to oral insect toxicity.

Implementation of IPM programs on European greenhouse tomato production areas: Tools and constraints

Whiteflies and whitefly-transmitted viruses are some of the major constraints on European tomato production. The main objectives of this study were to: identify where and why whiteflies are a major limitation on tomato crops; collect information about whiteflies and associated viruses; determine the available management tools; and identify key knowledge gaps and research priorities. This study was conducted within the framework of ENDURE (European Network for Durable Exploitation of Crop Protection Strategies). Two whitefly species are the main pests of tomato in Europe: Bemisia tabaci and Trialeurodes vaporariorum. Trialeurodes vaporariorum is widespread to all areas where greenhouse industry is present, and B. tabaci has invaded, since the early 1990’s, all the subtropical and tropical areas. Biotypes B and Q of B. tabaci are widespread and especially problematic. Other key tomato pests are Aculops lycopersici, Helicoverpa armigera, Frankliniella occidentalis, and leaf miners. Tomato crops are particularly susceptible to viruses causingTomato yellow leaf curl disease (TYLCD). High incidences of this disease are associated to high pressure of its vector, B. tabaci. The ranked importance of B. tabaci established in this study correlates with the levels of insecticide use, showing B. tabaci as one of the principal drivers behind chemical control. Confirmed cases of resistance to almost all insecticides have been reported. Integrated Pest Management based on biological control (IPM-BC) is applied in all the surveyed regions and identified as the strategy using fewer insecticides. Other IPM components include greenhouse netting and TYLCD-tolerant tomato cultivars. Sampling techniques differ between regions, where decisions are generally based upon whitefly densities and do not relate to control strategies or growing cycles. For population monitoring and control, whitefly species are always identified. In Europe IPM-BC is the recommended strategy for a sustainable tomato production. The IPM-BC approach is mainly based on inoculative releases of the parasitoids Eretmocerus mundus and Encarsia formosa and/or the polyphagous predators Macrolophus caliginosus and Nesidiocoris tenuis. However, some limitations for a wider implementation have been identified: lack of biological solutions for some pests, costs of beneficials, low farmer confidence, costs of technical advice, and low pest injury thresholds. Research priorities to promote and improve IPM-BC are proposed on the following domains: (i) emergence and invasion of new whitefly-transmitted viruses; (ii) relevance of B. tabaci biotypes regarding insecticide resistance; (iii) biochemistry and genetics of plant resistance; (iv) economic thresholds and sampling techniques of whiteflies for decision making; and (v) conservation and management of native whitefly natural enemies and improvement of biological control of other tomato pests.

Control biològic del Rhynchophorus ferrugineus a partir de diferents soques de nematodes entomopatògens i la seva problemàtica a Catalunya

En el present treball s’ha avaluat el potencial dels nemàtodes entomopatògens per a controlar la plaga de R. ferrugineus. Per fer-ho, s’ha determinat la susceptibilitat d’aquesta a 4 espècies diferents de nemàtodes: Steinernema carpocasae (soca B14, IDEBIO, BIOVERD), Steinernema feltiae (soca D114), Steinernema sp. (D122) i Heterorhabditis bacteriophora (soca DG46). D’altra banda, s’ha determinat la predació de Steinernema carpocapsae per part de l’àcar Centroupeda almerodai (Acari: Acaridae) per comprovar si aquest pot influir negativament en l’efectivitat de S. carpocapsae com agent de control biològic. S’ha vist que el morrut de les palmeres és molt susceptible als nemàtodes entomopatògens en especial una soca comercial (S. carpocapsae), la qual produeix mortalitats del 91,67%. Hi ha evidències de que l’àcar C. almerodai depreda les formes infectives de S. carpocapsae encara que no és suficient important com perquè es vegi compromès l’efectivitat com a bioinsecticida. L’ús de nemàtodes entomopatògens com a control biològic és una alternativa viable als mètodes químics de eficàcia similar però menys respectuosos amb el medi ambient.

Technology, business models and network structure in the airline industry

Network airlines have been increasingly focusing their operations on hub airports through the exploitation of connecting traffic, allowing them to take advantage of economies of traffic density, which are unequivocal in the airline industry. Less attention has been devoted to airlines? decisions on point-to-point thin routes, which could be served using different aircraft technologies and different business models. This paper examines, both theoretically and empirically, the impact on airlines ?networks of the two major innovations in the airline industry in the last two decades: the regional jet technology and the low-cost business model. We show that, under certain circumstances, direct services on point-to-point thin routes can be viable and thus airlines may be interested in deviating passengers out of the hub.

Technology, business models and network structure in the airline industry

Network airlines have been increasingly focusing their operations on hub airports through the exploitation of connecting traffic, allowing them to take advantage of economies of traffic density, which are unequivocal in the airline industry. Less attention has been devoted to airlines' decisions on point-to-point thin routes, which could be served using different aircraft technologies and different business models. This paper examines, both theoretically and empirically, the impact on airlines' networks of the two major innovations in the airline industry in the last two decades: the regional jet technology and the low-cost business model. We show that, under certain circumstances, direct services on point-to-point thin routes can be viable and thus airlines may be interested in deviating passengers out of the hub. Keywords: regional jet technology; low-cost business model; point-to-point network; hub-and-spoke network JEL Classi…fication Numbers: L13; L2; L93

Price policies and Price dispersion in the private healthcare insurance industry: The Catalan case

We present an overlapping generations model that explains price dispersion among Catalonian healthcare insurance firms. The model shows that firms with different premium policies can coexist. Furthermore, if interest rates are low, firms that apply equal premium to all insureds can charge higher average prices than insurers that set premiums according to the risk of insured. Economic theory, health insurance, health economics.