Diverse outcomes of photodynamic antimicrobial chemotherapy on five Enterococcus faecalis strains

Objectives In the present study, the effectiveness of Photodynamic Antimicrobial Chemotherapy (PACT) was evaluated on planktonic cells and biofilms of five Enterococcus faecalis clinical isolates. Methods Planktonic cells and biofilms of E. faecalis E2, E3, ER3/2s, OS16 and AA-OR34 were grown in SDMY medium plus 0.4% glucose. Approximately 5.0 × 107 CFU planktonic cells and 24 h biofilms were subjected to PACT using the combination of Light Emitting Diodes (LEDs, Biotable®) and Photogem®. The metabolic activity of bacterial cells was evaluated by a resazurin assay. Biomass values of the biofilms were determined by a crystal violet assay. Results Compared to the water-treated control group, gradual increases of light energy led to greater reduction of metabolic activity of planktonic cells and biofilms of E. faecalis when the combination of LEDs and Photogem® was applied. Photogem® alone significantly reduced the metabolic activity of planktonic cells, whereas LEDs or Photogem® alone did not result in biofilm viability changes. PACT yielded similar antimicrobial outcomes on planktonic cells of all tested E. faecalis strains, whereas biofilms of E. faecalis E3, ER3/2s and OS16 were more resistant to PACT than biofilms of E. faecalis E2 and AA-OR34. Conclusions The efficacy of PACT on E. faecalis biofilms was strain dependent. PACT demonstrated its potential as an adjuvant antimicrobial treatment by killing of E. faecalis planktonic and biofilm cells

Sistema de AVAC para um oceanário com aproveitamento da água do mar

Trabalho final de mestrado para obtenção do grau de Mestre em Engenharia MecânicaEste trabalho aborda a temática do aproveitamento da água do mar nos sistemas de Aquecimento, Ventilação e Ar Condicionado. Esta utilização é pouco usual no nosso país e nesse sentido pretende-se com este trabalho apresentar um estudo comparativo utilizando uma solução tradicional com água corrente no sistema de produção, com uma solução com aproveitamento a água do mar. Esta comparação será aplicada num edifício com localização perto do mar, mais propriamente a um Oceanário, com localização prevista no porto do Funchal. De forma a chegar à solução proposta de climatização foi necessário determinar as cargas térmicas do edifício e efetuar o seu dimensionamento. Posteriormente foi realizada a escolha de equipamentos e materiais adequados tendo em conta a utilização de água do mar para o sistema de climatização, bem como para a solução tradicional com água corrente. A seleção dos equipamentos foi sempre realizada com o intuito de reduzir os consumos energéticos e de exploração para ambas as soluções. A comparação entre os dois sistemas de climatização é efetuada com os mesmos pressupostos. As ferramentas utilizadas durante a realização deste trabalho foram o Autocad, o software de simulação térmica Hourly Analys Program (HAP) da Carrier e softwares de seleção de alguns equipamentos que foram aplicados nas soluções. Os sistemas de produção que foram alvo de estudo e comparação, foram os chillers com condensação a água do mar e chillers com condensação a ar, para a solução tradicional. A potência de arrefecimento obtida para a instalação foi 390 kW e 47 kW para o aquecimento. A solução com aproveitamento de água do mar requer um investimento inicial em equipamentos de 179.039,60 Euros (sem IVA), enquanto que a solução tradicional custa 142.346,47 Euros (sem IVA). No entanto, a estes valores acrescenta-se o custo com a infraestrutura para a captação de água do mar de 900.000 Euros (que são diluídos ao longo do tempo) e na solução tradicional o custo anual com a aquisição de sal (para os tanques) de 130.000 Euros. Constatou-se, através de uma análise económico-financeira, que o sistema de produção através de chillers com condensação a água do mar apresenta maior vantagem em termos de investimento, eficiência, rentabilidade, manutenção, e com menor impacto ambiental, uma vez que apresenta um custo anual inferior em 16,3% face ao da solução tradicional e porque em 8 anos o investimento fica pago.This paper addresses the usage of sea water in Heating, Ventilation and Air Conditioning systems. This usage is not usual in our Country, reason why in this paper it is intended to elaborate a comparative study between using the traditional solution (with current water) in the production system, and a solution of using sea water. This comparison is done using a building located near the sea, more specifically an Oceanarium located in the port of Funchal. In order to achieve the proposed air conditioning solution, it was necessary to determine the thermal loads of the building and to calculate its sizing. Subsequently, the choice of suitable equipment and materials was made, taking into account the usage of sea water for the air conditioning system, as well as for the traditional solution the usage of current water. The selection of equipment was always carried out in order to reduce energy and exploration consumption for both solutions. The comparison between the two air conditioning systems was made considering the same assumptions. The tools used during the elaboration of this paper were Autocad, Carrier's Hourly Analyzes Program (HAP) thermal simulation software, as well as a software for selecting some of the equipment that was applied to the solutions. The production systems object of this study and under comparison were the chillers with condensation through sea water, and chillers with condensation through for the traditional solution. The cooling power required for the installation is of 390 kW and for the heating is of 47 kW. The solution using sea water requires an initial investment in equipment of 179,039.60 Euros (without IVA), while the traditional solution costs 142,346.47 Euros (without IVA). However, to the previous amounts must be added the cost of infrastructure for the capture of sea water, equivalent to 900,000 Euros (which are diluted over time), and for the traditional solution the annual cost of acquiring salt (for tanks), equivalent to 130,000 Euros. It was concluded, through the economic-financial analysis performed, that the production system through chillers with sea water condensation, which presents the greatest advantage in terms of investment, efficiency, profitability, maintenance, and with less environmental impact, once it has a 16.3% lower annual cost than the traditional solution and because in 8 years the investment is paid.N/