Modelling of a wastewater treatment plant using GPS-X

Dissertation to obtain the degree of Master in Chemical and Biochemical Engineering

Predictive analytical and numerical modeling for orthogonal cutting

In this thesis, a predictive analytical and numerical modeling approach for the orthogonal cutting process is proposed to calculate temperature distributions and subsequently, forces and stress distributions. The models proposed include a constitutive model for the material being cut based on the work of Weber, a model for the shear plane based on Merchants model, a model describing the contribution of friction based on Zorev���s approach, a model for the effect of wear on the tool based on the work of Waldorf, and a thermal model based on the works of Komanduri and Hou, with a fraction heat partition for a non-uniform distribution of the heat in the interfaces, but extended to encompass a set of contributions to the global temperature rise of chip, tool and work piece. The models proposed in this work, try to avoid from experimental based values or expressions, and simplifying assumptions or suppositions, as much as possible. On a thermo-physical point of view, the results were affected not only by the mechanical or cutting parameters chosen, but also by their coupling effects, instead of the simplifying way of modeling which is to contemplate only the direct effect of the variation of a parameter. The implementation of these models was performed using the MATLAB environment. Since it was possible to find in the literature all the parameters for AISI 1045 and AISI O2, these materials were used to run the simulations in order to avoid arbitrary assumption.

Prepara����o e caracteriza����o de filmes polim��ricos inteligentes incorporando grafenos para aplica����es biom��dicas

O objectivo deste trabalho foi combinar o comportamento magn��tico de micropart��culas de ��xido de grafeno (GO) modificado com Fe3O4 (GO - 0%, 0.05%, 0.1% e 0.2%) com as propriedades do pol��mero ��lcool polivin��lico (PVA), nomeadamente a sua elasticidade, de forma a obter-se materiais polim��ricos com capacidade de revers��o das suas caracter��sticas estruturais, topogr��ficas e consequentemente controlar as suas caracter��sticas de transporte por ajuste de campo magn��tico. Preparou-se e caracterizou-se filmes/membranas polim��ricas de PVA com GO na presen��a e aus��ncia de campo magn��tico. Caracterizou-se a morfologia destas membranas, atrav��s de microscopia ��ptica e de varrimento electr��nico; o efeito na superf��cie de membranas por incorpora����o de GO atrav��s de ��ngulos de contacto, a avalia����o da estabilidade estrutural e qu��mica atrav��s de estudos de inchamento e degrada����o, adsor����o de prote��nas e o impacto da presen��a de GO e o seu comportamento magn��tico na permeabilidade a gases. As membranas apresentaram boa afinidade com o GO, e um bom alinhamento das micropart��culas quando expostas a campo. A estabilidade estrutural foi avaliada durante um per��odo de imers��o de 28 dias, usando uma solu����o de PBS a 0.01M, a pH 6.9 e a 37��C. A an��lise dos espectros de UV-Vis obtidos para solu����o de imers��o ao longo do tempo n��o revelaram degrada����o das membranas. O efeito na rugosidade da superf��cie das membranas por incorpora����o de GOs obteve-se atrav��s de ensaios de ��ngulos de contacto de glicerol. Verificou-se um aumento destes com o aumento de %GO; uma diminui����o dos ��ngulos quando as membranas humidificadas foram expostas a um campo magn��tico de intensidade 0.0832T; e um aumento destes nas membranas expostas a humidade e temperatura controlada, a 50% e 17��C. Foi observado o efeito do conte��do magn��tico existente nas membranas alinhadas e n��o-alinhadas, com diferentes %GO, no desempenho da adsor����o de BSA, submetidas a campo. Verificou-se um aumento de adsor����o na membrana com menor %GO, devido provavelmente ao aumento da sua rugosidade; e a diminui����o de adsor����o com o aumento de intensidade de campo. Nos ensaios de permeabilidade, observou-se que a membrana de PVA (0% GO) �� mais perme��vel ao CO2 do que ao O2. As membranas com GOs (0.05% e 0.1%) apresentam uma maior permeabilidade ao O2 do que ao CO2, devendo-se isto a uma prov��vel altera����o topogr��fica das membranas por incorpora����o das micropart��culas j�� referidas.

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 Asker��d, 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.

Effects of an exercise program on the functional capacity of patients with chronic Chagas' heart disease, evaluated by cardiopulmonary testing

INTRODUCTION: Despite all efforts to restrict its transmission, Chagas' disease remains a severe public health problem in Latin America, affecting 8-12 million individuals. Chronic Chagas' heart disease, the chief factor in the high mortality rate associated with the illness, affects more than half a million Brazilians. Its evolution may result in severe heart failure associated with loss of functional capacity and quality of life, with important social and medical/labor consequences. Many studies have shown the beneficial effect of regular exercise on cardiac patients, but few of them have focused on chronic Chagas' heart disease. METHODS: This study evaluated the effects of an exercise program on the functional capacity of patients with chronic Chagas' disease who were treated in outpatient clinics at the Evandro Chagas Institute of Clinical Research and the National Institute of Cardiology, Rio de Janeiro, Brazil. The exercises were performed 3 times a week for 1 h (30 min of aerobic activity and 30 min of resistance exercises and extension) over 6 months in 2010. Functional capacity was evaluated by comparing the direct measurement of the O2 uptake volume (VO2) obtained by a cardiopulmonary exercise test before and after the program (p < 0.05). RESULTS: Eighteen patients (13 females) were followed, with minimum and maximum ages of 30 and 72 years, respectively. We observed an average increase of VO2peak &gt; 10% (p = 0.01949). CONCLUSIONS: The results suggest a statistically significant improvement in functional capacity with regular exercise of the right intensity.

Efeito do teor em Y2O3 nos catalisadores suportados de 8%Ni/��-Al2O3 durante a rea����o de oxida����o parcial do Metano para produ����o de Hidrog��nio

Neste trabalho avaliou-se o desempenho de cinco catalisadores de N��quel suportados em ��-Alumina, com diferentes teores em ��tria, durante a rea����o de Oxida����o Parcial do Metano para a produ����o de Hidrog��nio: 8%Ni/��-Al2O3, 8%Ni/2%Y2O3.��-Al2O3, 8%Ni/2,5%Y2O3.��-Al2O3, 8%Ni/5%Y2O3.��-Al2O3 e 8%Ni/Y2O3. Foram realizados testes catal��ticos numa Unidade de Rea����o acoplada a um equipamento de an��lise, microGC. A rea����o decorreu �� temperatura de 800 ��C, num reator laboratorial de quartzo, durante 18 horas, com uma mistura pura de CH4 e O2 (Condi����o Concentrada). Os resultados demonstraram um aumento de atividade para os catalisadores de suporte misto com maior teor em Y2O3. Usando o mesmo procedimento, a rea����o de OPM foi realizada tamb��m para outra mistura reacional de CH4 e O2, mas agora dilu��da em H��lio (Condi����o Dilu��da). Estes resultados permitiram avaliar a velocidade de rea����o e a atividade dos catalisadores (TOF), para diferentes valores de temperatura, numa situa����o inicial de aus��ncia de coque. Numa segunda etapa, avaliou-se o desempenho dos mesmos materiais durante 2 horas de rea����o �� temperatura constante de 800 ���. Finalmente, atrav��s da t��cnica de carateriza����o de XPS, identificaram-se as esp��cies presentes na superf��cie dos catalisadores. Os resultados sugerem que h�� forma����o de um composto intermedi��rio NiYO3 formado entre o metal e o promotor Y2O3, conferindo atividade e estabilidade aos catalisadores e reduzindo a deposi����o de coque. O catalisador com maior teor em Y2O3 (8%Ni/5%Y2O3.��-Al2O3) foi o mais beneficiado com a adi����o do promotor, demonstrando melhor desempenho para a produ����o de H2 na Rea����o de Oxida����o Parcial do Metano.

Desempenho ambiental do transporte rodovi��rio ligeiro de passageiros em Portugal

O sector autom��vel tem um papel importante na sociedade actual, sendo um dos motores do crescimento econ��mico de v��rios pa��ses. Mas aliado ao seu desenvolvimento, est��o problemas ambientais com grande relev��ncia actual, como as emiss��es de poluentes atmosf��ricos pelo uso dos ve��culos. Contudo, n��o �� apenas a fase de uso do autom��vel que est�� ligada a impactos ambientais, sendo importante avaliar as restantes fases do ciclo de vida. Para o panorama nacional, os estudos neste sector n��o se encontram muito desenvolvidos. O objectivo da presente disserta����o passa pela avalia����o do desempenho ambiental do sector dos ve��culos ligeiros de passageiros em Portugal, estabelecendo uma compara����o entre as v��rias tecnologias autom��veis que o comp��em, mediante o uso da metodologia de an��lise de ciclo de vida (ACV). O desempenho ambiental dos ve��culos foi traduzido segundo a metodologia de avalia����o de impactes EcoBlok. Para o ano de 2013 um ve��culo m��dio portugu��s consumiu 11,8 m3 de ��gua, utilizou 2,8 t eq. de recursos, ocupou 54 m2 eq. de solo, emitiu 3,4 t de CO2 eq e 150 kg de NOx eq para a atmosfera, emitiu 600 kg de N eq. para a ��gua e o solo, e gerou 3,5 mg de dioxinas e furanos. Com a introdu����o de mais ve��culos el��ctricos a baterias na frota perspectivam-se redu����es ao n��vel do consumo de recursos, de emiss��es de gases com efeito de estufa e de polui����o do ar. No entanto, para o consumo de ��gua, uso do solo, emiss��es para o solo e ��gua e forma����o de dioxinas e furanos prev��em-se aumentos. A fase de manufactura, que �� dilu��da ao longo da vida ��til do ve��culo, �� respons��vel por mais de metade dos impactos ambientais gerados ao n��vel do uso do solo, da polui����o da ��gua e do solo e da forma����o de dioxinas e furanos. Por sua vez, a fase de uso do ve��culo �� determinante nos impactes sobre a polui����o do ar e emiss��es de gases com efeito de estufa, sendo respons��vel por mais de 80% dos resultados. As conclus��es retiradas com a realiza����o desta disserta����o s��o ��teis, na medida em que podem auxiliar o desenvolvimento de pol��ticas de incentivos para a mudan��a de comportamentos da popula����o face aos transportes. Por outro lado, permite perceber que as tecnologias menos poluentes t��m ainda um longo caminho a percorrer para que se tornem, globalmente, a melhor alternativa de mobilidade face ��s tecnologias convencionais.

Desempenho ambiental do transporte rodovi��rio pesado em Portugal

Os transportes rodovi��rios s��o essenciais para a sociedade actual. Deles depende directamente a mobilidade de milh��es de pessoas diariamente, assim como o funcionamento de diversos sectores econ��mico em Portugal e no mundo. Existem diversos estudos focados na press��o ambiental associada �� opera����o de ve��culos pesados. Todavia, o estudo de press��es inerentes ��s restantes fases do ciclo de vida permanece pouco desenvolvido carecendo de informa����o compar��vel. O objectivo da presente tese passa por avaliar o desempenho ambiental do transporte pesado rodovi��rio a n��vel nacional, atrav��s da aplica����o da metodologia de an��lise de ciclo de vida (ACV). Na fase de quantifica����o do desempenho ambiental foi utilizada a metodologia EcoBlok considerando o uso de recursos e emiss��es de poluentes. No ano de 2013 o transporte pesado de mercadorias consumiu 12,8 hm3 eq. de ��gua e 3 097 kt eq. de recursos; ocupou 119 km2.ano eq. de solos; emitiu 3 253 kt CO2 eq. de GEE; 121 kt NOx eq. de poluentes atmosf��ricos; 197 kt N eq. de poluentes para o solo e meios h��dricos e 1,3 kg TCDD eq. de dioxinas e furanos. A fase de opera����o �� a que mais contribui para o total de press��es contabilizadas no subsector mencionado. O transporte de passageiros registou, para o total da frota activa em 2013 um total de 1,7 hm3 eq. de ��gua extra��da; 221 kt eq. de recursos consumidos; 14,6 km2.ano eq. de solos usados; 234 kt CO2 eq. de GEE; 10,4 kt NOx eq. de poluentes atmosf��ricos; 16,9 kt N eq. de emiss��es para o solo e meios h��dricos e 0,1 kg TCDD eq. de dioxinas e furanos emitidos. O destaque vai igualmente, para a fase de opera����o, a que mais contribui para a press��o total averiguada. Os resultados e conclus��es obtidas ao longo do estudo podem revelar-se ��teis para a concep����o de pol��ticas de transporte e tomada de decis��o, na medida em que permitem a compara����o com o desempenho ambiental de outros modos e sistemas de transporte.

Desenvolvimento piloto de novas tipologias de fibras sint��ticas

O presente trabalho, desenvolvido nas instala����es da FISIPE, teve como objectivo a caracteriza����o de fibra oxidada (FOX),actualmente em desenvolvimento, com vista ao controlo de processo e de qualidade, e centrou-se em quatro par��metros: i. Densidade; ii. ��ndice de Aromaticidade; iii. ��ndice de Oxig��nio Limitante; iv. Grupos funcionais. No estudo da densidade realizou-se: a. Consolida����o do m��todo actualmente usado na empresa, observando-se uma redu����o da incerteza para metade (��0,005 gcm-3). b. An��lise de diferentes amostras de FOX que apresentaram valores entre 1,348-1,387 gcm-3, que atendendo �� incerteza do m��todo, se encontram dentro dos valores de refer��ncia (1,35-1,39 gcm-3). c. Previs��o de densidades ao longo da etapa de estabiliza����o oxidativa. Confirmou-se ser apenas poss��vel pela express��o apresentada numa das fontes consultada. Para o ��ndice de Aromaticidade (AI) efectuou-se: a. Estudo de quatro m��todos de integra����o de curvas de DSC para determina����o do calor de combust��o que permite determinar o AI. Verificou-se que o mais indicado seria o uso da temperatura de on-set como limite inferior �� linha de base de integra����o. b. An��lise de diferentes amostras de FOX, observando-se valores de AI entre os 66% e 81%. Na determina����o do ��ndice de Oxig��nio Limitante, par��metro exclusivo de qualidade, analisaram-se amostras de cabo pela adapta����o da norma ASTM D 2863-06a. Obtiveram-se valores acima dos 40%O2 para a fibra oxidada. Para a verifica����o dos grupos funcionais realizou-se: a. An��lise de FTIR, confirmando-se o desaparecimento de grupos nitrilo em fun����o do tempo de oxida����o, e a forma����o de bandas conjugadas e sobrepostas, indicando a presen��a de estruturas ciclizadas e aromatizadas. b. Proposta de um mecanismo reaccional para a reac����o de oxida����o de uma determinada fibra precursora. Com o intuito de minimizar o tempo de caracteriza����o das FOX, procurou-se ainda encontrar uma correla����o entre a densidade e o ��ndice de Aromaticidade, tanto ao longo da etapa de oxida����o, como da fibra oxidada final. Conclui-se que n��o �� poss��vel estabelecer uma rela����o matem��tica para as amostras analisadas.

Relationship between plasma creatinine concentration and glomerular filtration in preterm newborn infants

Fluid management and dosage regimens of drugs in preterm infants should be based on the glomerular filtration rate. The current methods to determine glomerular flitration rate are invasive, time-consuming, and expensive. In contrast, creatinine clearance can be easy obtained and quickly determined. The purpose of this study was to compare plasma creatinine on the third and seventh day of life in preterm newborn infants, to evaluate the influence of maternal creatinine, and to demonstrate creatinine clearance can be used as a reliable indicator of glomerular filtration rate. We developed a prospective study (1994) including 40 preterm newborns (gestational age &lt; 37 weeks), average = 34 weeks; birth weight (average) = 1840 g, in the first week of life. Inclusion criteria consisted of: absence of renal and urinary tract anomalies; O2 saturation 3 92%; adequate urine output (&gt;1ml/kg/hr); normal blood pressure; absence of infections and no sympathomimetic amines in use. A blood sample was collected to determine plasma creatinine (enzymatic method) on the third and seventh day of life and creatinine clearance (CrCl) was obtained using the following equation: <IMG SRC="http:/img/fbpe/rhc/v54n4/1065e1.gif" WIDTH=287 HEIGHT=96>, k = 0.33 in preterm infant All plasma creatinine determinations showed normal values [third day: 0.78 mg/dl �� 0.24 (mean �� SD)and seventh day: 0.67 mg/dl �� 0.31 - (p&gt;0.05)&#093;. Also all creatinine clearance at third and seventh day of life were normal [third day: 19.5 ml/min �� 5.2 (mean �� SD) and seventh day: 23.8 ml/min �� 7.3 - (p&gt;0,05)&#093;. All preterm infants developed adequate renal function for their respective gestational age. In summary, our results indicate that, for clinical practice, the creatinine clearance, using newborn length, can be used to estimate glomerular filtration rate in preterm newborn infants.

Observations of air composition in Brazil between the Equator and 20��s during the dry season.

Field measurement programs in Brazil during the dry season months of August and September in 1979 and 1980 have demonstrated the great importance of the continental tropics in global air chemistry. Especially in the mixed layer, the air composition over land is much different from that over the ocean and the land areas are clearly longe scale sources of many inportant trace gases. During the dry season much biomass, burning takes place especially in the cerrado regions leading to substantial emission of air pollutants, such as CO, NOx, N2O, CH4 and other hydrocarbons. Ozone concentrations are alsoenhanced due to photochemical reactions. Biogenic organic emissions from tropical forests play likewise an important role in the photochemistry of the atmosphere. Carbon monoxide was found to be present in high concentrations in the boundary layer of the tropical forest, but ozone concentrations were much lower than in the cerrado.

Avalia����o da implementa����o da fase III da zona de emiss��es reduzidas de Lisboa

Os efeitos de uma qualidade do ar reduzida s��o sentidos principalmente em centros urbanos, como Lisboa, onde persistem situa����es de concentra����es elevadas de di��xido de azoto (NO2) e mat��ria particulada (PM10), originadas pelo tr��fego autom��vel. Para diminuir a concentra����o desses poluentes foi implementada uma Zona de Emiss��es Reduzidas (ZER) em Lisboa, que entrou na fase III em janeiro de 2015. Avaliou-se a evolu����o da qualidade do ar nos ��ltimos cinco anos em Lisboa, nomeadamente as exced��ncias aos valores limite legais de curto prazo para NO2 e PM10, bem como a influ��ncia da meteorologia na sua ocorr��ncia. A qualidade do ar, em geral, melhorou, registando-se a maioria das exced��ncias no outono e inverno, em dias ��teis e final da tarde e in��cio da manh��, per��odos coincidentes com a maior intensidade de tr��fego rodovi��rio. A altura da base da invers��o t��rmica e a velocidade do vento s��o mais reduzidas em dias com exced��ncias, o que indicia um papel relevante da meteorologia. A avalia����o do impacte da fase II da ZER nas exced��ncias aos valores limite revelou que o n��mero de exced��ncias e a dura����o dos epis��dios de polui����o diminu��ram, mas mais significativamente em esta����es fora da ZER. Analisou-se a influ��ncia da fase III da ZER na composi����o da frota autom��vel e nas emiss��es associadas de NOX e PM na Avenida da Liberdade, com base nos dados obtidos antes (2014) e depois (2015) da fase III. Verificou-se uma melhoria na frota em toda a cidade, mais acentuada na zona 2 que na zona 1. Concluiu-se que o impacte da fase III foi reduzido, principalmente na zona 1, possivelmente relacionado com a escassa fiscaliza����o. Caso o n��mero de ve��culos se tivesse mantido igual entre 2014 e 2015, teria sido poss��vel uma redu����o de 23% nas emiss��es de NOX e de 8% nas de PM.

Inc��ndios na Amaz��nia Brasileira: estimativa da emiss��o de gases do efeito estufa pela queima de diferentes ecossistemas de Roraima na passagem do evento &#8220;El Nino&#8221; (1997/98)

Foi estimada a &#225;rea queimada, a biomassa vegetal total acima e abaixo do solo, a forma&#231;&#227;o de carv&#227;o, a efici&#234;ncia de queimada e a concentra&#231;&#227;o de carbono de diferentes paisagens naturais e agroecossistemas que foram atingidos pelos inc&#234;ndios ocorridos durante a passagem do &#8220;El Ni&#241;o&#8221; em 1997/98 no Estado de Roraima, extremo norte da Amaz&#244;nia Brasileira. O objetivo foi o de calcular a emiss&#227;o bruta de gases do efeito estufa liberados por combust&#227;o das diversas classes de biomassa que comp&#245;em cada tipo fitofision&#244;mico atingido. A &#225;rea total efetivamente queimada foi estimada entre 38.144-40.678 km2, sendo 11.394-13.928 km2 de florestas prim&#225;rias (intactas, em p&#233;) e, o restante, de savanas (22.583 km2), campinas / campinaranas (1.388 km2) e ambientes florestais j&#225; transformados como pastagens, &#225;rea agr&#237;colas e florestas secund&#225;rias (2.780 km2). O total de carbono afetado pelos inc&#234;ndios foi de 42,558 milh&#245;es de toneladas, sendo que 19,73 milh&#245;es foram liberados por combust&#227;o, 22,33 milh&#245;es seguiram para a classe de decomposi&#231;&#227;o e 0,52 milh&#245;es foram depositados nos sistemas na forma de carv&#227;o (estoque de longo prazo). A emiss&#227;o bruta de gases do efeito estufa, em milh&#245;es de toneladas do g&#225;s, considerando apenas o emitido por combust&#227;o foi de 17,3 de CO2, 0,21-0,35 de CH4, 1,99-3,68 de CO, 0,001-0,003 de N,O, 0,06-0,09 de NOx e 0,25 de hidrocarbonetos n&#227;o-met&#226;nicos (HCNM). O total de carbono equivalente a CO2 emitido por combust&#227;o, quando considerado o potencial de aquecimento global de cada g&#225;s em um horizonte de tempo de 100 anos utilizado pelo IPCC, foi de 6,1-7,0 milh&#245;es de toneladas.

Respiratory characteristics of Hoplostenum littorale (Siluriformes, Callichthyidae)

Hematological parameters, intraerythrocytic phosphates, hemoglobin, and whole blood Bohr effect of the South American armored catfish Hoplostenum littorale were studied during different seasons of the year. In addition, the degree of dependence on air breathing was determined for this species. The hematological parameters presented seasonal variations, which were not correlated to oxygen, temperature, and water level oscillations. Five anodic hemoglobin fractions were detected in starch gel electrophoresis. In addition to ATP, GTP and Fe-GTP being detected, 2,3-DPG was also detected in red blood cells of H. littorale. The latter is an intraerythrocytic phosphate characteristic to red blood cells of mammalians. The increased production of 2,3-DPG could be associated with decreasing Hb-O2 affinity and both features could be related to environmental temperature increase. Whole blood Bohr effect was influenced by water temperature. This study confirms H. littorale to be continuous and not obligate air breather, under all dissolved oxygen level conditions.

Antibacterial properties of fibrous stents coated with silver oxide nanocoatings

Stents are rigid and perforated tubular structures, which are inserted into blood vessels in order to prevent or inhibit the constriction of blood flow, restoring the normal blood flow, when blood vessels are clogged, being used in 70% of angioplasties. These medical devices assume great importance in the treatment of cardiovascular diseases (CVD) which are the leading cause of death worldwide. In the European Union CVD account for 40% of deaths and assume an estimated annual cost of 196 billion euros[1]. Stents must possess certain requirements, in order to, adequately, perform its function, such as biocompatibility (so that its use does not c ause damage on the health of its user), mechanical strength, radiopacity (so that it is easy to view), longitudinal flexibility, ease of handling, corrosion resistance and having high strength and high radial expansion ability to recover. Stents can be made of different materials, but metals, particularly stainless steel, are the most common. However, metallic stents present several dRawbacks such as corrosion and restenosis, leading to health complications for the patient, or even death. In order to minimize these disadvantages, new materials, like fibrous materials, have been used [2]. Monofilaments present high potential for stents development because, in addition to its biocompatibility, these materials allow the application of various surface treatments, such as antibacterial coatings. Furthermore, monofilament exhibit excellent mechanical properties, like greater stiffness and good results when subjected to compression, tensile and bending forces, since these forces will be directly supported by the monofilament [3]. To minimize the reaction of the human body and Limit the adhesion of microorganisms to the stent surface, some coatings have been developed, including the use of novel metals with antimicrobial properties, like silver. The main objective of this study was the development of fibrous stents, incorporation of silver oxide nanocoating. For the development of the stent, polyester monofilaments with 0.27mm of diameter were used in braiding technology, with a mandrel diameter of 6mm and a braiding angle of 35���. The mechanical behaviour of the stent were evaluated by mechanical testing under longitudinal and radial compression, bending. The results of compressive strength tests are according with value from literature: 1.13 to 2.9 N for radial compression and 0. 16-5.28N to longitudinal compression. From literature is also possible to verify that stents must present 75% of unchanged diameter during the bending test and must possess a porosity between 70% and 80% [4]. The produced polyester stent presents values of 1.29N for radial compression, 0.23N for longitudinal compression, 80% of porosity and 85.5% of unchanged diameter, during bending tests. For the antibacterial functionalization, silver oxide nanocoatings were prepared, through reactive magnetron g, with an Ag target in an Ar +O2 atmosphere. In order to evaluate the nanostructure and morphology of the coatings, d ifferent technique s like X-ray diffraction (XRD), scanning electron microscopy (SEM) and and X- ray photoelectron spectroscopy (XPS were used. From the analyses of XRD it is possible to verify that the peaks corresponds to planes of Ag2 O and MATERIAIS 2015 Porto, 21-23 June, 2015 characterize a cubic phase. The presence of Ag2 O is corroborated by XPS spectrum, where it is possible to observe silver, not only, in oxide state, but a lso in mettalic state, and it is possible to verify the presence of silver clusters, confirmed by SEM analysis. Films��� roughness and topography, parameters influencing the wettability of the surface and microorganism adhesion, were measured by Atomic Force Microscopy (AFM), and it was observed that the roughness is very low (under 10 nm). Coatings��� hydrophobicity and surface tension parameters were determined by contact angle measurement, and it was verified the hydrophobic behavior of the coatings. For antibacterial tests were used Staphylococcus epidermidis strain (IE186) and Staphylococcus aureus(ATCC 6538), and halo inhibition zone tests were realized. Ag+release rates were studied by means of inductively coupled plasma mass spectrometry (ICP -MS). The obtained results suggest that silver oxide coatings do not modify significantly surface properties of the substrate, like hydrophobicity and roughness, and present antimicrobial properties for both bacteria used.