Microbial Diversity of a Brazilian Coastal Region Influenced by an Upwelling System and Anthropogenic Activity

BACKGROUND: Upwelling systems are characterised by an intense primary biomass production in the surface (warmest) water after the outcrop of the bottom (coldest) water, which is rich in nutrients. Although it is known that the microbial assemblage plays an important role in the food chain of marine systems and that the upwelling systems that occur in southwest Brazil drive the complex dynamics of the food chain, little is known about the microbial composition present in this region. METHODOLOGY/PRINCIPAL FINDINGS: We carried out a molecular survey based on SSU rRNA gene from the three domains of the phylogenetic tree of life present in a tropical upwelling region (Arraial do Cabo, Rio de Janeiro, Brazil). The aim was to analyse the horizontal and vertical variations of the microbial composition in two geographically close areas influenced by anthropogenic activity (sewage disposal/port activity) and upwelling phenomena, respectively. A lower estimated diversity of microorganisms of the three domains of the phylogenetic tree of life was found in the water of the area influenced by anthropogenic activity compared to the area influenced by upwelling phenomena. We observed a heterogenic distribution of the relative abundance of taxonomic groups, especially in the Archaea and Eukarya domains. The bacterial community was dominated by Proteobacteria, Cyanobacteria and Bacteroidetes phyla, whereas the microeukaryotic community was dominated by Metazoa, Fungi, Alveolata and Stramenopile. The estimated archaeal diversity was the lowest of the three domains and was dominated by uncharacterised marine Crenarchaeota that were most closely related to Marine Group I. CONCLUSIONS/SIGNIFICANCE: The variety of conditions and the presence of different microbial assemblages indicated that the area of Arraial do Cabo can be used as a model for detailed studies that contemplate the correlation between pollution-indicating parameters and the depletion of microbial diversity in areas close to anthropogenic activity; functional roles and geochemical processes; phylogeny of the uncharacterised diversity; and seasonal variations of the microbial assemblages

Endarterectomia de carótida sob anestesia local: evolução de 104 pacientes Carotid endarterectomy under regional anesthesia: follow-up of 104 patients

A estenose carotídea cervical é uma das causas mais freqüentes de acidente vascular cerebral isquêmico. A endarterectomia de carótida é um tratamento eficaz para lesões estenóticas moderadas e graves, tanto sintomáticas quanto assintom��ticas. A endarterectomia realizada sob anestesia local permite a monitorização neurológica do paciente durante o ato cirúrgico. O objetivo deste trabalho foi avaliar as complicações cirúrgicas e acompanhar a evolução dos pacientes submetidos a endarterectomia sob anestesia local em nossa instituição, comparando os resultados com outras publicações. 104 pacientes foram submetidos a 110 procedimentos no período de abril de 1996 a maio de 2002. 64 pacientes eram sintomáticos (61,54%) e 40 assintomáticos (38,46%). Todos possuíam grau de estenose carotídea igual ou superior a 70%. Os pacientes foram avaliados retrospectivamente. O tempo de evolução variou de um a 72 meses (média: 29,5). Três pacientes apresentaram hematoma cervical necessitando drenagem cirúrgica. Dois pacientes (1,92%) tiveram acidente vascular cerebral do mesmo lado da endarterectomia no pós-operatório e outros dois durante o seguimento. Dois pacientes faleceram em decorrência da cirurgia (1,92%). Os resultados desta série, comparados com a literatura, permitem concluir que a endarterectomia é uma forma segura de tratamento para as estenoses carotídeas moderadas e graves.<br>Cervical carotid stenosis is one of the main causes of ischemic stroke. Carotid endarterectomy is a safe procedure for treatment of moderate and severe symptomatic and asymptomatic carotid stenosis. Regional anesthesia allows neurological evaluation of the patient during the surgery. We reviewed the results of 104 patients operated on at our institution under regional anesthesia during the period of April 1996 and May 2002. 64 patients were symptomatic (61.54%) and 40 asymptomatic (38.46%). All patients had carotid stenosis over 70%. The patients were followed from one to 72 months (Mean: 29.5). Three patients had cervical hematoma, that required surgical drainage. Two patients had minor stroke at the same side of the endarterectomy at the post-operative period and another two during the follow-up (1.92%). Two patients died due to complications related to the surgery (1.92%). Our results, compared with the literature, show that endarterectomy is a safe procedure to treat moderate or severe carotid artery stenosis

The isotope exchange depth profiling (IEDP) technique using SIMS and LEIS

The determination of the mass transport kinetics of oxide materials for use in electrochemical systems such as fuel cells, sensors and oxygen separators is a significant challenge. Several techniques have been proposed to derive these data experimentally with only the oxygen isotope exchange depth profile technique coupled with secondary ion mass spectrometry (SIMS) providing a direct measure of these kinetic parameters. Whilst this allows kinetic information to be obtained, there is a lack of knowledge of the surface chemistry of these complex processes. The advent of low-energy ion scattering (LEIS) now offers the opportunity of correlating exchange kinetics with chemical processes at materials atomic surfaces, giving unprecedented levels of information on electrochemical systems with isotopic discrimination. Here, the challenges of these techniques, including sample preparation, are discussed and the advantages of the combined approach of SIMS and LEIS illustrated with reference to key literature data

In-situ high-temperature X-ray diffraction of thin films: chemical expansion and kinetics

This chapter reviews the use of in-situ X-ray diffraction analyses for exploring the chemical expansion produced by oxygen stoichiometry changes in thin oxide films during oxidation and reduction, as well as the kinetics of oxygen exchange at the surface of the films. This technique has demonstated to serve as a non-invasive and very selective complementary tool for fundamental studies on mixed ionic-electronic conducting materials.Peer Reviewe