15 resultados para concentration profile
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1st European IAHR Congress, 6-4 May, Edinburgh, Scotland
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River Flow, Vol. 2
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Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina
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Dissertation for the degree of Doctor of Philosophy in Physics
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RESUMO: O efluxo de compostos antimicrobianos é um mecanismo importante na multirresistência em bactérias. Bombas de efluxo codificadas em plasmídeos, como a QacA e a Smr, estão implicadas na susceptibilidade reduzida a biocidas, geralmente utilizados na prevenção e controlo de infecções nosocomiais, incluindo as causadas por estirpes de Staphylococcus aureus resistentes à meticilina (MRSA). Neste trabalho pretendeu-se avaliar a relevância de QacA e Smr no perfil de susceptibilidade dos isolados clínicos MRSA SM39 e SM52, que transportam os plasmídeos pSM39 e pSM52 com os determinantes qacA e smr, respectivamente. A actividade de efluxo das estirpes SM39 e SM39 curada (sem pSM39) e das estirpes SM52 e RN4220:pSM52 (estirpe susceptível RN4220 transformada com pSM52) foi caracterizada por: (1) determinação da concentração mínima inibitória (CMI) de biocidas, corantes e antibióticos, na ausência e presença dos inibidores de efluxo tioridazina, clorpromazina, verapamil e reserpina; e (2) fluorometria em tempo-real. A determinação de CMIs demonstrou que a actividade de efluxo mediada por QacA e Smr está envolvida na susceptibilidade reduzida aos biocidas e corantes testados, que incluíram o brometo de hexadeciltrimetilamónio, a cetrimida, o cloreto de benzalcónio, a berberina, o cloreto de dequalínio, a pentamidina e o brometo de etídeo. Os ensaios fluorométricos confirmaram a elevada actividade de efluxo presente nas estirpes com os genes qacA ou smr. A determinação de CMIs para antibióticos β-lactâmicos em conjunto com o teste da nitrocefina revelou a presença simultânea do gene qacA e de uma β-lactamase no plasmídeo pSM39. Este trabalho evidencia a importância das bombas de efluxo QacA e Smr na resistência a biocidas em estirpes MRSA e na sobrevivência destas estirpes em ambiente hospitalar e na comunidade, para além de destacar a questão da potencial co-resistência entre biocidas e antibióticos.--------------- ABSTRACT: Drug efflux has become an important cause of multidrug resistance (MDR) in bacteria. Plasmid-encoded MDR efflux pumps, such as QacA and Smr, are implicated in reduced susceptibility to biocides, generally used in the prevention and control of nosocomial infections, including the ones caused by methicillin-resistant Staphylococcus aureus (MRSA). In this work, we aimed to evaluate the relevance of QacA and Smr to the susceptibility profile of the clinical MRSA isolates SM39 and SM52, which harbor the plasmids pSM39 and pSM52 that carry the determinants qacA and smr, respectively. Efflux activity of strain SM39 and its plasmid-free counterpart, SM39 cured, SM52 and RN4220:pSM52 (susceptible strain RN4220 transformed with pSM52) was characterized by: (1) determination of minimum inhibitory concentration (MIC) of biocides, dyes and antibiotics, in the absence and presence of the efflux inhibitors thioridazine, chlorpromazine, verapamil and reserpine; and (2) real-time fluorometry. MIC determination showed that QacA and Smr mediated efflux was involved in the reduced susceptibility profile to the biocides and dyes tested, which included hexadecyltrymethylammonium bromide, cetrimide, benzalkonium chloride, berberine, dequalinium chloride, pentamidine and ethidium bromide. Fluorometric assays confirmed the higher efflux activity present in strains harboring qacA or smr genes. Moreover, MIC determination for β-lactam antibiotics together with the nitrocefin test confirmed the presence of a β-lactamase in the plasmid carried by SM39 strain, pSM39. This work highlights the relevance of QacA and Smr to the biocide resistance in MRSA strains, and consequently to their survival and maintenance in the hospital environment and in the community. Furthermore, the presence of a β-lactamase and qacA determinants in the the same plasmid reinforces the question of the potencial biocide/antibiotic co-resistance in MRSA strains.
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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Dissertação para obtenção do Grau de Doutor em Química Sustentável
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RESUMO: Em 2006, foi aprovada uma nova política governamental para a saúde mental intitulada “Uma Visão para a Mudança”, a qual está neste momento no sétimo ano de implementação. A política descreve um enquadramento para o desenvolvimento e promoção da saúde mental positiva para toda a Comunidade e para a prestação de serviços acessíveis, baseados na comunidade, serviços especializados para pessoas com doença mental. A implementação da política e o tornar a “Vision for Change” uma realidade têm sido problemáticos, com críticas consideráveis por parte dos intervenientes, relativas à lenta e desconexa implementação. Este estudo fornece informação sobre as características dos serviços de três importantes tipos de instituições de saúde mental comunitária a nível nacional, nomeadamente Hospitais de Dia, Centros de Dia e residências comunitárias operantes 24 horas. A pesquisa analisa objetivos e funções, perfis dos pacientes, atividades terapêuticas, a eficácia das redes de comunicação e beneficia da perspectiva dos funcionários sobre o que mudou no terreno ao longo dos últimos sete anos. As questões identificadas a partir das características dos três serviços dizem respeito a todos. Os participantes indicaram que o ethos da recuperação parece ter alcançado um papel mais central no tratamento do paciente na comunidade mas reconheceram que o desafio de integrar os princípios de recuperação na prática clínica se mantém presente. Parece ser reconhecida a importância da planificação do cuidado individual nos serviços comunitários e os entrevistados indicaram que existe um empenho para garantir o envolvimento do usuário do serviço. Há diferenças entre os „pontos de vista do pessoal‟ e os „pontos de vista dos representantes‟ sobre uma série de aspetos da prestação de serviços. Este é o primeiro estudo irlandês deste género a examinar a prestação de serviços das três principais instituições comunitárias de saúde mental num só estudo. Estes serviços representam um enorme investimento em recursos, quer a nível monetário, quer humano. O estudo examinou os desafios e as questões fundamentais que lhe são aplicáveis e que têm impacto nestes três tipos de prestação de serviços. Também forneceu informações sobre os elementos de mudança positiva, os quais se começam a focar lentamente na prestação do serviço, assim como na importância da centralidade do utilizador do serviço e na promoção de um ethos da recuperação.----------ABSTRACT: In 2006, a new Government policy for mental health “A Vision for Change” was endorsed and is currently in the seventh year of implementation. The policy describes a comprehensive framework for building and fostering positive mental health across the entire community and for providing accessible, community based, specialist services for people with mental illness. The implementation of the policy and turning “Vision for Change” into reality has been problematic with considerable criticism from stakeholders concerning slow and disjointed implementation. This study provides information on three key community mental health service settings, namely Day Hospitals, Day Centres and 24 Hour Community Residences at a national level. The research looks at aims and functions, patient profiles, therapeutic activities, effectiveness of key communication networks and gains an insight from staff on what has changed on the ground over the past seven years. Issues identified from the three service settings pertain to all. Participants indicated that the recovery ethos appears to have moved to a more central role in patient care in the community but acknowledged that the challenge of integrating recovery principles in clinical practice remains present. The importance of individual care planning appears to be recognised in community services and respondents indicated that efforts are being made to ensure service user involvement. There were differences between „staff views‟ and „advocate views‟ on a number of aspects of service provision. This is the first Irish study of its kind to examine service provision across the three main community mental health settings in one study. These services represent a huge investment in resources both on a monetary and human level. This study has examined the challenges and key issues which are applicable and impacting on all three types of service provision. It has also provided information on the elements of positive change, which are slowly embedding themselves in service provision such as the importance of the centricity of the service user and the promotion of a recovery ethos.
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Dissertação para obtenção do Grau de Doutor em Engenharia do Ambiente
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Using a green methodology, 17 different poly(2-oxazolines) were synthesized starting from four different oxazoline monomers. The polymerization reactions were conducted in supercritical carbon dioxide under a cationic ring-opening polymerization (CROP) mechanism using boron trifluoride diethyl etherate as the catalyst. The obtained living polymers were then end-capped with different types of amines, in order to confer them antimicrobial activity. For comparison, four polyoxazolines were end-capped with water, and by their hydrolysis the linear poly(ethyleneimine) (LPEI) was also produced. After functionalization the obtained polymers were isolated, purified and characterized by standard techniques (FT-IR, NMR, MALDI-TOF and GPC). The synthesized poly(2-oxazolines) revealed an unusual intrinsic blue photoluminescence. High concentration of carbonyl groups in the polymer backbone is appointed as a key structural factor for the presence of fluorescence and enlarges polyoxazolines’ potential applications. Microbiological assays were also performed in order to evaluate their antimicrobial profile against gram-positive Staphylococcus aureus NCTC8325-4 and gram-negative Escherichia coli AB1157 strains, two well known and difficult to control pathogens. The minimum inhibitory concentrations (MIC)s and killing rates of three synthesized polymers against both strains were determined. The end-capping with N,N-dimethyldodecylamine of living poly(2- methyl-2-oxazoline) and poly(bisoxazoline) led to materials with higher MIC values but fast killing rates (less than 5 minutes to achieve 100% killing for both bacterial species) than LPEI, a polymer which had a lower MIC value, but took a longer time to kill both E.coli and S.aureus cells. LPEI achieved 100% killing after 45 minutes in contact with E. coli and after 4 hours in contact with S.aureus. Such huge differences in the biocidal behavior of the different polymers can possibly underlie different mechanisms of action. In the future, studies to elucidate the obtained data will be performed to better understand the killing mechanisms of the polymers through the use of microbial cell biology techniques.
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Deep-eutectic solvents (DES) are considered novel renewable and biodegradable solvents, with a cheap and easy synthesis, without waste production. Later it was discovered a new subclass of DES that even can be biocompatible, since their synthesis uses primary metabolites such as amino acids, organic acids and sugars, from organisms. This subclass was named natural deep-eutectic solvents (NADES). Due to their properties it was tried to study the interaction between these solvents and biopolymers, in order to produce functionalized fibers for biomedical applications. In this way, fibers were produced by using the electrospinning technique. However, it was first necessary to study some physical properties of NADES, as well as the influence of water in their properties. It has been concluded that the water has a high influence on NADES properties, which can be seen on the results obtained from the rheology and viscosity studies. The fluid dynamics had changed, as well as the viscosity. Afterwards, it was tested the viability of using a starch blend. First it was tested the dissolution of these biopolymers into NADES, in order to study the viability of their application in electrospinning. However the results obtained were not satisfactory, since the starch polymers studied did not presented any dissolution in any NADES, or even in organic solvents. In this way it was changed the approach, and it was used other biocompatible polymers. Poly(ethylene oxide), poly(vinyl alcohol) and gelatin were the others biopolymers tested for the electrospinning, with NADES. All polymers show good results, since it was possible to obtain fibers. However for gelatin it was used only eutectic mixtures, containing active pharmaceutical ingredients (API’s), instead of NADES. For this case it was used mandelic acid (antimicrobial properties), choline chloride, ibuprofen (anti-inflammatory properties) and menthol (analgesic properties). The polymers and the produced fibers were characterized by scanning electron microscope (SEM), Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). With the help of these techniques it was possible to conclude that it was possible to encapsulate NADES within the fibers. Rheology it was also study for poly(ethylene oxide) and poly(vinyl alcohol), in a way to understand the influence of polymer concentration, on the electrospinning technique. For the gelatin, among the characterization techniques, it was also performed cytotoxicity and drug release studies. The gelatin membranes did not show any toxicity for the cells, since their viability was maintained. Regarding the controlled release profile experiment no conclusion could be drawn from the experiments, due to the rapid and complete dissolution of the gelatin in the buffer solution. However it was possible to quantify the mixture of choline chloride with mandelic acid, allowing thus to complete, and confirm, the information already obtained for the others characterization technique.
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Double Degree. A Work Project, presented as part of the requirements for the Award of a Master’s Degree in Finance from NOVA – School of Business and Economics and a Masters Degree in Management from Louvain School of Management
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The paper studies the relationship between four differently rated bank’s financial profile and their standalone credit rating issued by Moody’s. The comparative analysis shows an example that despite their pricing power and geographical coverage, larger banks do not necessarily have better credit ratings. Instead, business model and risk appetite seem to be the defining factors of banks’ vulnerability to shocks, such as the Spanish real estate crisis. The risk-return relationship is also identified in the banks’ fundamentals meaning that while expansionary strategy in riskier asset classes enhances margins, it also potentially distorts the credit risk profile.