960 resultados para autotrophic respiration
Resumo:
Desde a descoberta em 1999 do primeiro vulcão de lama no Golfo de Cádis, cerca de 40 locais, de profundidade variável entre os 200 e os 3900 m, com diferentes graus de emissão de hidrocarbonetos foram localizados e amostrados dentro do programa IOC-UNESCO “Training Through Research (TTR) “ e mais recentemente dentro do projecto europeu HERMES. Neste estudo investigamos as comunidades da macrofauna dos vulcões de lama do Golfo de Cádis utilizando uma diversidade de equipamento de amostragem quantitativo e não quantitativo. Mais de 14550 espécimes foram examinados e incluídos nos diferentes grupos taxonómicos, sendo fornecida uma lista taxonómica detalhada com o menor nível taxonómico possível. A biodiversidade, distribuição dos principais taxa, as espécies quimiossintéticas e a biodiversidade regional e substituição de espécies são apresentados e discutidos. Dentro da macrofauna, os bivalves (nomeadamente super-familia Thyasiroidea, espécies quimisimbióticos e comunidade de bivalves) e os ofiurideos são estudados em pormenor. Os Thyasiroidea colhidos nos vulcões de lama do Golfo de Cádis são revistos. Das sete espécies identificadas, apenas uma Thyasira vulcolutre. sp. nov se encontra associada a um ambiente quimiossintético. Esta espécie é restrita a locais activos, mas não se verificam padrões de distribuição para as outras espécies. Os bivalves quimiosimbióticos amostrados são revistos. Das 10 espécies fortemente associadas a ambientes quimiossintéticos duas Solemyidae, Petrasma elarraichensis sp. nov. e Acharax gadirae sp. nov., uma Lucinidae, Lucinoma asapheus sp. nov., e uma Vesicomyidae, Isorropodon megadesmus sp. nov. são descritas e comparadas com similares das respectivas famílias. As comunidades de bivalves foram analisadas em detalhe e do estudo de 759 espécimes (49 espécies em 21 familias) descreve-se a diversidade e padrões de distribuição. Os Ophiuroidea amostrados nos vulcões de lama e ambientes batiais adjacentes são revistos. Treze espécies são incluídas em 4 famílias, Ophiacanthidae, Ophiactidae, Amphiuridae e Ophiuridae e são identificadas, tendo sido descrita uma nova espécie Ophiopristis cadiza sp. nov. Rácios isotópicos (δ13C, δ15N, δ34S) foram determinados em várias espécies no intuito de investigar a ecologia trófica das comunidades bênticas dos vulcões do Golfo de Cádis. Os valores de δ13C para os bivalves Solemyidae, Lucinidae e Thyasiridae estão de acordo com os valores para outros bivalves conhecidos por possuírem simbiontes tiotróficos. Por outro lado os valores de δ13C e δ34S para Bathymodiolus mauritanicus sugerem a ocorrência de metanotrofia. A análise da fauna heterotrófica indica igualmente que as espécies habitantes da cratera dos vulcões de lama derivam a sua nutrição de fontes quimiossintéticas. A indicação pela análise isotópica que as bactérias autotróficas contribuem substancialmente para a nutrição dos bivalves hospedeiros, levou-nos a investigar os endossimbiontes e as suas relações filogenéticas relativamente a outros bivalves através da análise comparativa de análises de sequências de 16S ribossomal RNS. Análises moleculares PCR-DGGE (Denaturing Gradient Gel Electrophoresis) e clonagem de genes de bacterias 16S rRNA confirmaram a presença de simbiontes oxidantes de enxofre e colocam a possibilidade de uma simbiose dupla para o B. mauritanicus. A diversidade microbiana dentro dos Frenulata foi igualmente estudada recorrendo a métodos moleculares e revelou a não existência de padrão entre espécies, vulcões, profundidade e idade do animal sugerindo assim a não procura de simbiontes específicos.
Resumo:
Coral reefs are of utmost ecological and economical importance but are currently in global decline due to climate change and anthropogenic disturbances. Corals, as well as other cnidarian species, live in symbiosis with photosynthetic dinoflagellates of the genus Symbiodinium. This relationship provides the cnidarian host with alternative metabolic pathways, as the symbionts translocate photosynthetic carbon to the animal. Besides this autotrophic nutrition mode, symbiotic cnidarians also take up organic matter from the environment (heterotrophy). The nutritional balance between auto- and heterotrophy is critical for the functioning, fitness and resilience of the cnidariandinoflagellate symbiosis. New methodological approaches were developed to better understand the role of auto- and heterotrophy in the ecophysiology of cnidarians associated with Symbiodinium, and the ecological implications of this trophic plasticity. Specifically, the new approaches were developed to assess photophysiology, biomass production of the model organism Aiptasia sp. and molecular tools to investigate heterotrophy in the cnidarian-dinoflagellate symbiosis. Using these approaches, we were able to non-invasively assess the photophysiological spatial heterogeneity of symbiotic cnidarians and identify spatial patterns between chlorophyll fluorescence and relative content of chlorophyll a and green-fluorescent proteins. Optimal culture conditions to maximize the biomass production of Aiptasia pallida were identified, as well as their implications on the fatty acid composition of the anemones. Molecular trophic markers were used to determine prey digestion times in symbiotic cnidarians, which vary between 1-3 days depending on prey species, predator species and the feeding history of the predator. This method was also used to demonstrate that microalgae is a potential food source for symbiotic corals. By using a stable isotope approach to assess the trophic ecology of the facultative symbiotic Oculina arbuscula in situ, it was possible to demonstrate the importance of pico- and nanoplanktonic organisms, particularly autotrophic, in the nutrition of symbiotic corals. Finally, we showed the effects of functional diversity of Symbiodinium on the nutritional plasticity of the cnidarian-dinoflagellate symbiosis. Symbiont identity defines this plasticity through its individual metabolic requirements, capacity to fix carbon, quantity of translocated carbon and the host’s capacity to feed and digest prey.
Resumo:
The aim of this study was to record experiences of three meditation conditions: Ratio Breathing, Transcendental Meditation and Zazen, with special reference to sport, health, neuro-physiology and sense of coherence. The participants (N=9), seven males and two females were all British, actively competing across a range of individual and team sports, with no experience of using meditation techniques or practices in their sporting or daily lives. Their mean age was 31.56 years with an age range of 22 to 44 years. The study employed a within-subjects, repeated measures design, with each participant practising each meditation condition in a randomly counterbalanced order. Integrative findings support the value of all three meditation conditions for health and to a lesser extent for sport, especially with regard to their effect on focus. All three meditation conditions were associated with a decrease in respiration. The differential effect of the meditations was apparent. Participants valued Ratio breathing for its effect on concentration, Transcendental Meditation for its depth of meditation and Zazen for its effect on self and removal of external distractions. These qualitative findings were associated with differentially significant quantitative effects on lowered respiration rate in the Ratio Breathing group, increased physical relaxation and alpha activity in the Transcendental Meditation group, and increases in both alpha and theta activity in the Zazen group.
Resumo:
Dissertação mest., Gestão da Água e da Costa, Universidade do Algarve, 2007
Resumo:
Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2007
Resumo:
Tese de Doutoramento, Ecologia, Especialidade de Ecofisiologia, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2007
Resumo:
Microplankton community, production, and respiration were studied alongside physical and chemical conditions at Sagres (SW Portugal) during the upwelling season, from May to September 2001. The sampling station was 5 km east of the upwelling center off Cabo S. Vicente, and 2 km of an offshore installation for bivalve aquaculture.
Resumo:
Senior thesis written for Oceanography 444
Resumo:
Senior thesis written for Oceanography 445
Resumo:
Resumo Uma estratégia de avaliação e prevenção de riscos na exposição a agentes químicos deve ter sempre em conta que a vigilância do ambiente de trabalho e a da saúde dos trabalhadores são aspectos complementares de uma mesma realidade – os riscos resultantes da interacção entre um agente químico e os trabalhadores a ele expostos. Se à Vigilância Ambiental compete apreciar o risco, pela caracterização do agente no ambiente de trabalho, a Vigilância Biológica pronuncia-se sobre a interacção entre o tóxico e o organismo, avaliando a resposta à agressão química e a evolução das reacções de adaptação ou de desajuste face à absorção do tóxico. Os Indicadores Biológicos, deste modo, assumem um estatuto de instrumento privilegiado na vigilância da saúde dos trabalhadores expostos, na medida em que medem a quantidade de tóxico que efectivamente penetrou e foi absorvido, ou o resultado (efeito) determinado por essa mesma dose. O presente estudo procura contribuir para a definição de um quadro metodológico de utilização dos Indicadores Biológicos na avaliação/gestão da exposição profissional ao chumbo, designadamente apreciando a variação da protoporfirina-zinco (PPZ), indicador até ao presente ainda não utilizado em Portugal. O chumbo é um metal de ocorrência natural, cujos níveis nos diversos ecossistemas resultam, principalmente, das actividades antropogénicas de natureza doméstica e industrial. A sua capacidade poluente é assinalável, representando uma fonte de exposição permanente para o homem, demonstrável pela sua constante presença no organismo apesar de não desempenhar qualquer tipo de função fisiológica. São actualmente inúmeras as suas aplicações, tornando a exposição profissional ao chumbo uma realidade vasta: indústrias de acumuladores eléctricos, de vidros, de plásticos e de munições, construção civil, manutenção e reparação automóvel e de navios, fabrico de tintas, indústrias electrónicas, fundições e actividades de soldadura são, entre outras, situações onde é uma realidade a ter em conta. A penetração dos compostos inorgânicos de chumbo no organismo efectua-se principalmente por via respiratória, não sendo, no entanto, desprezável, a sua penetração por via digestiva. As partículas absorvidas são transportadas pelo sangue principalmente ligadas aos eritrocitos (95%), distribuem-se pelos tecidos moles e depositam-se essencialmente no tecido ósseo, onde representam mais de 90% da carga corporal do total absorvido e tendo aí um elevado tempo de semi-vida (mais de 20 anos). Não é metabolizado no organismo e a sua eliminação efectua-se essencialmente por via renal,sendo igualmente excretado, em menor escala, através das fezes, do suor, da saliva, das faneras e do leite materno. O conhecimento científico evidencia que concentrações sanguíneas de chumbo entre 20 e 50 mg/dL são susceptíveis de determinar efeitos adversos no homem, podendo ser afectados o sistema hematopoiético, o sistema nervoso, o sistema cardiovascular, o sistema reprodutor e o sistema imunitário. Contudo, ainda muito há a clarificar no âmbito da toxicidade do chumbo. Os níveis de exposição a que correspondem as alterações nos diversos órgãos e sistemas continuam a ser motivo de alguma controvérsia. As características carcinogénicas e mutagénicas do chumbo são, ainda, um campo de vasta exigência de investigação. A intoxicação por chumbo e seus sais (Saturnismo) de origem ocupacional é reconhecida em Portugal como doença profissional (grupo 1 - Doenças Provocadas por Agentes Químicos, da Lista das Doenças Profissionais). É uma intoxicação do tipo crónico, fruto da absorção contínua de doses relativamente pequenas durante longo período, evidenciando-se no seu início por sinais e sintomas vagos e difusos de grande inespecificidade, que podem incluir, nomeadamente, perda de apetite, sabor metálico na boca, palidez, mal-estar e fadiga, cefaleias, mialgias e artralgias, irritabilidade, tremores finos, obstipação, cólicas abdominais, insónias, déficit da memória de curto prazo e da capacidade de concentração. Um importante conjunto de indicadores biológicos pode ser utilizado na vigilância periódica da saúde de trabalhadores nestas condições de exposição. Tais indicadores (de dose ou de efeito), encerram diferentes significados e comportam distintas exigências, competindo ao Médico do Trabalho, no âmbito dos programas de prevenção dos efeitos adversos relacionados com a exposição profissional a chumbo, seleccionar a sua utilização e interpretar a sua informação, de modo a avaliar a interacção do tóxico com o organismo numa fase de reversibilidade. O presente estudo envolveu 180 trabalhadores dos quais 110 apresentavam plumbémias (Pb-S) iguais ou superiores a 40 mg/dL. Além da Pb-S, a todos foi doseada a protoporfirina-zinco (PPZ) e efectuado o Hemograma e a cerca de 25% foi determinada a concentração do ácido d-aminolevulínico urinário (ALA-U). Os doseamentos da PPZ efectuados em amostra de sangue capilar através de um hematofluorímetro portátil revelaram-se de total fiabilidade, dando significado a uma técnica de fácil execução e baixo custo. A avaliação do tipo de colheita urinária para doseamento do ALA-U concluiu pela necessidade de recurso a urinas de 24 horas.Os resultados do estudo evidenciaram uma elevada associação entre a PPZ e a Pb-S, com uma maior magnitude e de início mais precoce do que o que registado na associação da Pb-S com o ALA-U. Revelaram, ainda, fracos níveis de associação da hemoglobina (e outros parâmetros hematológicos) com a Pb-S. E demonstraram para um cut-off de 100 mg/ dL de PPZ, taxa de falsos negativos e falsos positivos, para plumbémias a partir de 70 mg/dL, inferiores a 20%. Assim, concluiu-se que, nos protocolos de vigilância de saúde de trabalhadores expostos a chumbo, o doseamento da PPZ por hematofluorímetro, em sangue de colheita capilar, é adequado, fiável e de realização preferencial em relação ao do ALA-U. Concluiu-se, também, que a realização do hemograma apenas se justifica em situações individuais que clinicamente o tornem aconselhável. E que estes protocolos devem incluir a realização da Pb-S e da PPZ, podendo, em situações de controlo rigoroso (ambiental, biológico e clínico), basear-se apenas na determinação da PPZ reservando os outros indicadores para aprofundar a investigação médica nos casos de taxas elevadas desta ou de situações limitantes. ■ Résumée Une stratégie d’évaluation et de prévention des risques d’exposition aux agents chimiques doit toujours tenir en considération que la vigilance du lieu de travail et de la santé des travailleurs sont des aspects complémentaires d’une même réalité – les risques résultant d’une interaction entre l’agent chimique et les travailleurs exposés. Si c’est à la Vigilance Ambiantale de juger le risque, par la caractérisation de l’agent dans le lieu de travail, la Vigilance Biologique, elle, se prononce sur l’interaction entre le toxique et l’organisme, évaluant la réponse à l’agression chimique et l’évolution des réactions d’adaptation ou de rupture face à l’absorption du toxique. Les Indicateurs Biologiques assument ainsi un statut d’instrument privilégié de vigilance de la santé des travailleurs exposés, dans la mesure où ils déterminent la quantité de toxique qui a effectivement été pénétré et absorbé, ou le résultat (effet) déterminé par cette dose. Cette étude-ci cherche à contribuer à la définition d’un cadre méthodologique d’utilisation des Indicateurs Biologiques dans l’évaluation/ gestion de l’exposition professionnelle au plomb inorganique, évaluant spécialement le comportement de la protoporphirine-zinc (PPZ), indicateur pas encore utilisé au Portugal.Le plomb est un métal d’occurrence naturelle dont les niveaux dans les différents écosystèmes en résultent, principalement, des activités anthropogéniques de nature domestique et industrielle. Sa capacité polluante peut être signalée, représentant une source d’exposition permanente pour l’homme, celle-ci démontrable par sa présence continue dans l’organisme, même si elle n’y accomplit aucune fonction physiologique. Actuellement ses applications sont innombrables, faisant de l’exposition professionnelle au plomb une réalité de grande ampleur : industries d’accumulateurs électriques, de verre, de plastique et de munitions, bâtiments, manutention et réparation automobile et navale, fabrication d’encres, industries électroniques, fontes et activités de soudure sont, entre autres, des situations réelles a en tenir compte. La pénétration du plomb inorganique dans l’organisme se fait principalement par voie respiratoire, pouvant se faire également par voie digestive. Les particules absorbées sont transportées par le sang, surtout liées aux érythrocytes (95%), se repartent à travers les tissus mous et se déposent essentiellement dans le tissu osseux, où elles représentent plus de 90% de la charge corporelle de ce qui a été absorbé et ont un temps de demi-vie élevé (plus de 20 ans). Le plomb n’est pas métabolisé dans l’organisme et son élimination se fait essentiellement par voie rénale, pouvant tout de même, à une moindre échelle, être excrété dans les fèces, de la sueur, de la salive, des ongles, des cheveux et du lait maternel. La connaissance scientifique met en évidence que des concentrations sanguines de plomb entre 20 et 50 mg/dL sont susceptibles de déterminer des effets adverses dans l’homme, pouvant les systèmes hématopoïétique, nerveux, cardiovasculaire, reproducteur et immunitaire en être affectés. Cependant, il en reste beaucoup à éclaircir dans le domaine de la toxicité du plomb. Les niveaux d’exposition auxquels correspondent les modifications des divers organes et systèmes, demeurent toujours sujet de quelque controverse. Les caractéristiques carcinogèniques et mutagèniques du plomb restent toujours un champ d’investigation d’une grande exigence. L’intoxication par le plomb et ses sels (Saturnisme) d’origine occupationnelle est reconnue, au Portugal, comme une maladie professionnelle (groupe 1- Maladies Provoquées par des Agents Chimiques, de la Liste des Maladies Professionnelles). C’est une intoxication du tipe chronique, due à l’absorption continue de doses relativement petites pendant une longue période, mise en évidence à travers des signes et des symptômes vagues et diffus sans grande spécificité, lesquels peuvent inclure, particulièrement, le manque d’appétit, goût métallique dans la bouche, pâleur, malaise et fatigue, céphalées, myalgies et arthralgies, irritabilité, tremblements fins, constipation, coliques abdominales, insomnies, déficit de la mémoire à court terme et de la capacité de concentration.Un ensemble important d’indicateurs biologiques peut être employé dans la vigilance périodique de la santé des travailleurs dans ces conditions d’exposition. Ces indicateurs (de dose ou d’effet) renferment différentes significations et comportent diverses exigences, devant le Médecin de Travail, dans le domaine des programmes de prévention des effets adverses qui sont en relation avec l’exposition professionnelle au plomb, sélectionner son utilisation et interpréter son information de façon à évaluer l’interaction de l’élément toxique avec l’organisme à un stade de réversibilité. L’étude ci-présent engloba 180 travailleurs desquels 110 présentaient des plombémies (Pb-S) égales ou supérieures à 40 mg/dL. À part la Pb-S, la protoporphyrine-zinc (PPZ) leur a été prise en dosage et un Hémogramme fut effectué et fut déterminé l’acide d- aminolévulinique urinaire (ALA-U) sur environ 25% des travailleurs. Le dosage de la PPZ efectué en échantillon de sang capillaire par un fluorimètre portable, s’est accomplit d’une fiabilité total, donnant du sgnificat à une téchnique de facile execution et bas prix. L’évaluation de la prise urinaire par dosage du ALA-U conclut au besoin d’un recours aux urines de 24 heures Les résultats de l’étude ont mis en évidence une association élevée entre la PPZ et la Pb- S, avec une intensité majeure et de début plus précoce par rapport à celui qui fut registré lors de l’association de la Pb-S avec la ALA-U. Ces résultats ont également montré de faibles niveaux d’association entre l’hémoglobine (et autres paramètres hématologiques) et la Pb-S. Ils ont démontré aussi, une valeur de cut-off de 100 mg/dL de PPZ, des taux de faux négatifs et faux positifs, pour des plombémies de 70 mg/dL, inférieurs à 20%. On peut donc conclure que dans les protocoles de vigilance de la santé des travailleurs exposés au plomb, le dosage de la PPZ par fluorimetrie dans le sang capillaire est adéquat, fiable et de réalisation préférentielle par rapport à celui du ALA-U. On peut également conclure que la réalisation de l’hémogramme ne se justifie que dans les cas individuels où, cliniquement, celui-ci est conseillé. De plus, ces protocoles doivent inclure la réalisation de la Pb-S et de la PPZ, pouvant, en cas de contrôle rigoureux (ambiantal, biologique et clinique), s’appuyer que dans la détermination de la PPZ réservant les autres indicateurs pour approfondir l’investigation médicale dans les cas où les taux de celle-ci sont élevés ou dans les cas de situations limitantes. ■ Summary Any strategy to evaluate and prevent the risks of chemical agents exposure must always regard the work environment and workers health as complementary aspects of one reality - the resulting risks from the interaction between the chemical agent and the exposed workers. It is the responsibility of Environmental Monitoring to evaluate the risks of exposure by the characterization of the chemical agent in the work environment. Biological Monitoring, on the other hand, pronounces itself over the toxin and body interaction, evaluating human response to the chemical aggression and the body adaptations to the toxic absorption. Biological Exposure Indices (BEI) assume, therefore, a privileged status among exposed workers' health monitoring instruments, as they measure the actual penetrated and absorbed toxic quantity and the effect it produces. This research study aims to contribute to the definition of a methodological strategy on the utilization of BEI’s in evaluating inorganic lead's occupational exposure, more specifically appreciating the zinc protoporphyrin (ZPP) variation, an index that has never been taken under consideration in Portugal until now. Lead is a natural metal whose ecosystem’s levels are mainly due to domestic and industrial anthropogenic activities. Its pollutant capacity is notable, representing a permanent exposure risk shown by its constant presence in the human body, although it has no physiologic function. Nowadays, lead's applications are countless, turning its professional exposure a huge reality: storage batteries industries, glass industries, plasterers and munitions industries, building construction, ships and motor car maintenance and repairing, ink manufacture, electronics industries, foundries and other soldering activities are, among so many other, realities to attend to. Respiration is the main cause of human body's inorganic lead absorption, although digestive pathway must not to be ignored. The absorbed particles are transported by blood, essentially bounded to erythrocytes (95%). It is distributed by soft tissues and settled mainly on bone tissues, where it represents approximately 90% of the total body charge and has a high half-life time (more than 20 years). It is not metabolized by the organism, its elimination being effectuated by renal activity and, in smaller scale, through lees, sweat, saliva, nails, hair and maternal milk.Scientific knowledge shows that concentrations of lead in blood between 20 e 50 mg/dL are susceptible to determine adverse effects in man and able to affect the hematopoietic system, the nervous system, the cardiovascular system, the reproductive system and the immunological system. Nevertheless, there's still much to be learned and clarified about lead's toxicity. The correlation between exposure levels and human's systems and organs alteration levels continues to be a centre of controversies. Still, lead's carcinogenic and mutagenic characteristics continue to be a high demanding research field. Intoxication by lead and its compounds (saturnism), from occupational origin, is recognized in Portugal as an occupational disease, included in Group 1 - Chemical Agents Caused Diseases, on the Occupational Diseases List. It is a chronic intoxication caused by a continuous absorption of small doses, throughout a long period of time. Its signs and symptoms are diffuse and imprecise, of great unspecificity, such as loss of appetite, metallic flavor in the mouth, paleness, ailment and fatigue, headaches, myalgia and arthralgia, irritability, thin tremors, constipation, abdominal pain, insomnias, short memory loses and inability to concentrate. A considered number of BEI’s can be used in Periodic Health Monitoring of workers in such exposure conditions. Such BEI (dose indices or effect indices) provide different meanings and imply different procedures, being Occupational Doctors responsibility, in the context of lead related adverse effects preventive programmes, to select and interpret its information, in order to evaluate the interaction between toxic and organism in a reversible phase of the toxic action. The present research study involved 180 workers, 110 of which presented blood lead levels (PbB) above or equal to 40 mg/dL. Besides PbB, all workers has been evaluated for zinc protoporphyrin levels (PPZ) and submitted to a haemogram. About 25% of the workers were selected for d-aminolevulinic urinary acid (ALA-U) determination. The evaluation of PPZ, by a portable hematofluorometer using capillary blood samples, turned out to be an easy procedure with low costs and total warrantability. As in regard for ALA- U procedure, it was concluded the necessity of 24 hours urine samples. This research results underlined a strong connection between ZPP and PbB, which was found to to be stringer and to begin earlier than it was registered for PbB and ALA-U association. The same study also revealed a low association level between PbB and hemoglobin or other hematological indices. It was also verified less than 20% of false negatives and false positives cases when admitted a ZPP 100 mg/dL cut off value for PbB³ 70 mg/dL. As in result it was concluded that in Health Monit
Resumo:
The effects of swine wastewater-derived biogas on microalgae productivity were determined. Experiments were conducted in a closed photobioreactor containing digestate effluent as culturing media and biogas in the headspaceas source of CO2. Experiments were carried out under mixothrophic and autothrophic conditions. Results showed that autotrophic growth rate (0.6 d-1)was twofoldfaster than mixotrophic. Frequent reinjections of biogas containing up to 2,000 ppm of hydrogen sulfide was not inhibitory to microalgae growth. The rapid removal of H2S in the system suggests photobioreactors can be an interesting alternative to biogas purification. A model to estimate microalgae productivity based on the amount of available CO2, inorganic and organic carbon was developedand showed good data fit correlation (r²= 0.99).
Resumo:
Energy conservation in chemotrophic anaerobic bacteria is achieved by two possible processes, substrate level phosphorylation (SLP) and electron transfer phosphorylation (ETP). This second mechanism, also known as respiration, involves chemiosmotic coupling. However, a third mechanism for energy coupling was recently proposed: the flavin-based electron bifurcation (FBEB). (...)
Resumo:
At an intermediate or advanced stage, i.e. stage B or C, based on the Barcelona Clinic Liver Cancer classification of hepatocellular carcinoma (HCC), transarterial chemoembolization (TACE) may be offered as a treatment of palliative intent. We report the case of a patient suffering from acute respiratory distress syndrome after TACE with drug-eluting beads loaded with doxorubicin for HCC. To our knowledge, this is the first case described where a bronchoalveolar lavage was performed, and where significant levels of alveolar eosinophilia and neutrophilia were evident, attributed to a pulmonary toxicity of doxorubicin following liver chemoembolization. © 2014 S. Karger AG, Basel.
Resumo:
The metabolic and respiratory effects of intravenous 0.5 M sodium acetate (at a rate of 2.5 mmol/min during 120 min) were studied in nine normal human subjects. O2 consumption (VO2) and CO2 production (VCO2) were measured continuously by open-circuit indirect calorimetry. VO2 increased from 251 +/- 9 to 281 +/- 9 ml/min (P < 0.001), energy expenditure increased from 4.95 +/- 0.17 kJ/min baseline to 5.58 +/- 0.16 kJ/min (P < 0.001), and VCO2 decreased nonsignificantly (211 +/- 7 ml/min vs. 202 +/- 7 ml/min, NS). The extrapulmonary CO2 loss (i.e., bicarbonate generation and excretion) was estimated at 48 +/- 5 ml/min. This observation is consistent with 1 mol of bicarbonate generated from 1 mol of acetate metabolized. Alveolar ventilation decreased from 3.5 +/- 0.2 l/min basal to 3.1 +/- 0.2 l/min (P < 0.001). The minute ventilation (VE) to VO2 ratio decreased from 22.9 +/- 1.3 to 17.6 +/- 0.9 l/l (P < 0.005), arterial PO2 decreased from 93.2 +/- 1.9 to 78.7 +/- 1.6 mmHg (P < 0.0001), arterial PCO2 increased from 39.2 +/- 0.7 to 42.1 +/- 1.1 mmHg (P < 0.0001), pH from 7.40 +/- 0.005 to 7.50 +/- 0.007 (P < 0.005), and arterial bicarbonate concentration from 24.2 +/- 0.7 to 32.9 +/- 1.1 (P < 0.0001). These observations indicate that sodium acetate infusion results in substantial extrapulmonary CO2 loss, which leads to a relative decrease of total and alveolar ventilation.
Resumo:
Empirical evidence supports the hypothesis that emotional states might contribute to cardiovascular disease and health through multiple pathways. To the extent that the acute cardiovascular response to emotional events plays a role in cardiovascular health and disease, an essential step in order to understand this possible link is to define the hemodynamic response to affective challenges. This was the aim of the present study. We assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output, and total peripheral resistance (TPR) in response to 13 picture series in 18 men and 19 women (mean age 26) in order to investigate their hemodynamic responses associated with activation of the appetitive and defensive motivational systems underlying emotional experience. The hemodynamic parameters were recorded by finger-cuff photoplethysmography with Finometer™ (FMS Finapres Medical Systems, Amsterdam) and electrocardiography with the Lifeshirt system (VivoMetrics Inc., Ventura, California). Participants rated self-perceived pleasantness and arousal for each series. In men, BP and SV, but not TPR, increased with increasing self-rated arousal both for appetitive and defensive activation, whereas in women these relationships were almost absent, especially, for defensive activation. HR decelerated more in response to negative than positive and neutral pictures, and more so in men than women. These findings indicate striking sex differences. In particular, it is suggested that the sympathetic inotropic effect to the heart increases with increasing self-rated arousal strongly in men but only weakly in women. Regardless of sex differences, the modulation of the cardiovascular response to affective pictures along the dimensions of pleasantness and arousal is primarily myocardial, and the pattern of cardiovascular response is consistent with a configuration of cardiac sympathetic-parasympathetic coactivation. One possible implication of the observed sex differences concerns the link between affective states and cardiovascular health and disease. Men have a higher incidence of cardiovascular diseases than premenopausal women, and exaggerated sympathetic reactivity to emotional events is a potential pathophysiological mechanism. These findings extend current knowledge showing that under several acute behavioral challenges men demonstrate stronger cardiovascular reactivity than women.