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Search Results: 1 - 10 of 573323 matches for " Sandra M. F. O. Azevedo "
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Optimization of Nitrogen, Phosphorus and Salt for Lipid Accumulation of Microalgae: Towards the Viability of Microalgae Biodiesel  [PDF]
Carolina T. Miranda, Daniel V. N. de Lima, Georgia C. Atella, Paula F. de Aguiar, Sandra M. F. O. Azevedo
Natural Science (NS) , 2016, DOI: 10.4236/ns.2016.812055
In recent years, microalgae biodiesel has attracted expressive attention and investment, once it was considered a potential resource for energy. Although the wide use of microalgae biodiesel is restricted by its high production cost. For cost-efficient and sustainable production of biodiesel from microalgae, a proper understanding of the variables and their impacts on physiology of the strains is required. In this study, a simple factorial design 23 was used to find optimal conditions for the cultivation of Ankistrodesmus sp. and Chlamydomonas sp. in batch culture. The three components considered were nitrate, phosphate and sodium chloride, used to assess the metabolic versatility of the strains in brackish conditions. The results showed that culture medium with 0.04 g·L?1 nitrate, 0.01 g·L?1 phosphate and 5.0 g·L?1 sodium chloride resulted to be the most effective condition to growth and fatty acids accumulation. Using this optimal condition, Ankistrodesmus sp. and Chlamydomonas sp. increased in 2.1 and 2.4 folds their fatty acids yield, respectively. Importantly, this protocol reduced 75% of the nitrate and phosphate concentrations of the original medium (ASM-1). Additionally, fatty acids analysis found that these strains were mainly constituted of C16-C18, in accordance with the requirements for biodiesel production. The simple factorial design applied here proved to be an important tool towards a better understanding of synergistic effects of tested factors on microalgae metabolism, and the resulting information could be used effectively to improve microalgae cultivation.
Microalgae Lipid and Biodiesel Production: A Brazilian Challenge  [PDF]
Carolina T. Miranda, Roberta F. Pinto, Daniel V. N. de Lima, Carolina V. Viegas, Simone M. da Costa, Sandra M. F. O. Azevedo
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.615254
Abstract: Global increases in atmospheric CO2 and climate change are drawing considerable attention to identify sources of energy with lower environmental impact than those currently in use. Biodiesel production from microalgae lipids can, in the future, occupy a prominent place in energy generation because it represents a sustainable alternative to petroleum-based fuels. Several species of microalgae produce large amounts of lipids per biomass unit. Triacylglycerol is the fatty acid used for biodiesel production and the main source of energy reserves in microalgae. The current literature indicates that nutrient limitations can lead to triacylglycerol accumulation in different species of microalgae. Further efforts in microalgae screening for biodiesel production are needed to discover a native microalgae that will be feasible for biodiesel production in terms of biomass productivity and oil. This revision focuses in the biotechnological potential and viability of biodiesel production from microalgae. Brazil is located in a tropical region with high light rates and adequate average temperatures for the growth of microalgae. The wide availability of bodies of water and land will allow the country to produce renewable energy from microalgae.
Sublethal Microcystin Exposure and Biochemical Outcomes among Hemodialysis Patients
Elizabeth D. Hilborn, Raquel M. Soares, Jerome C. Servaites, Alvima G. Delgado, Valéria F. Magalh?es, Wayne W. Carmichael, Sandra M. F. O. Azevedo
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069518
Abstract: Cyanobacteria are commonly-occurring contaminants of surface waters worldwide. Microcystins, potent hepatotoxins, are among the best characterized cyanotoxins. During November, 2001, a group of 44 hemodialysis patients were exposed to microcystins via contaminated dialysate. Serum microcystin concentrations were quantified with enzyme-linked immunosorbent assay which measures free serum microcystin LR equivalents (ME). We describe serum ME concentrations and biochemical outcomes among a subset of patients during 8 weeks following exposure. Thirteen patients were included; 6 were males, patients’ median age was 45 years (range 16–80), one was seropositive for hepatitis B surface antigen. The median serum ME concentration was 0.33 ng/mL (range: <0.16–0.96). One hundred thirty nine blood samples were collected following exposure. Patients’ biochemical outcomes varied, but overall indicated a mixed liver injury. Linear regression evaluated each patient’s weekly mean biochemical outcome with their maximum serum ME concentration; a measure of the extrinsic pathway of clotting function, prothrombin time, was negatively and significantly associated with serum ME concentrations. This group of exposed patients’ biochemical outcomes display evidence of a mixed liver injury temporally associated with microcystin exposure. Interpretation of biochemical outcomes are complicated by the study population’s underlying chronic disease status. It is clear that dialysis patients are a distinct ‘at risk’ group for cyanotoxin exposures due to direct intravenous exposure to dialysate prepared from surface drinking water supplies. Careful monitoring and treatment of water supplies used to prepare dialysate is required to prevent future cyanotoxin exposure events.
Interaction of legionella pneumophila and helicobacter pylori with bacterial species isolated from drinking water biofilms
Maria S Gi?o, Nuno F Azevedo, Sandra A Wilks, Maria J Vieira, Charles W Keevil
BMC Microbiology , 2011, DOI: 10.1186/1471-2180-11-57
Abstract: Firstly, both pathogens were studied for auto- and co-aggregation with the species isolated from drinking water; subsequently the formation of mono and dual-species biofilms by L. pneumophila or H. pylori with the same microorganisms was investigated. Neither auto- nor co-aggregation was observed between the microorganisms tested. For biofilm studies, sessile cells were quantified in terms of total cells by SYTO 9 staining, viable L. pneumophila or H. pylori cells were quantified using 16 S rRNA-specific peptide nucleic acid (PNA) probes and cultivable cells by standard culture techniques. Acidovorax sp. and Sphingomonas sp. appeared to have an antagonistic effect on L. pneumophila cultivability but not on the viability (as assessed by rRNA content using the PNA probe), possibly leading to the formation of viable but noncultivable (VBNC) cells, whereas Mycobacterium chelonae increased the cultivability of this pathogen. The results obtained for H. pylori showed that M. chelonae and Sphingomonas sp. help this pathogen to maintain cultivability for at least 24 hours.It appears that M. chelonae may have an important role in the survival of both pathogens in drinking water. This work also suggests that the presence of some microorganisms can decrease the cultivability of L. pneumophila but not the viability which indicates that the presence of autochthonous microorganisms can lead to misleading results when the safety of water is assessed by cultivable methods alone.In natural environments, bacteria can adhere to surfaces forming a complex structure called a biofilm. When embedded in biofilms, microorganisms can be protected from several adverse factors such as temperature, low nutrients and the presence of biocides [1-6]. Therefore, understanding the ecology of microorganisms in this structure is fundamental in order to obtain a comprehensive knowledge of real systems. In nature, biofilms typically consist of many species of microorganisms that can interact with each o
Caracteriza o por FT-IR de agentes de cura utilizados em resinas epoxídicas-II-polimercaptana, poliaminoamida e amina modificada
Rom?o Benedita M. V.,Diniz Milton F.,Azevedo Margarete F. P.,Louren?o Vera L.
Polímeros , 2003,
Abstract: Amostras de resina epoxídica (EP) curadas com compostos à base depolimercaptana (SH), SH na presen a de poliamino amida, e amina modificada, constituindo, respectivamente, os sistemas epoxídicos (SE) 1, 2 e 3, foram preparadas segundo condi es estabelecidas pelas curvas de calorimetria exploratória diferencial (DSC) de EP e agentes de cura, ou endurecedores (AC) e analisadas, antes e após prepara o do SE, por espectroscopia no infravermelho com transformada de Fourier (FT-IR) por meio de técnicas de transmiss o (pastilha de KBr, pirólise por bico de Bunsen, e pirólisecontrolada (CONTROLPIR/FT-IR) dentro da faixa de temperatura fornecida pela análise termogravimétrica (TG) dos SE 1, 2 e 3, para a caracteriza o de cada AC. Para tal fim, as absor es FT-IR do pirolisado líquido obtido pela metodologia CONTROLPIR/FT-IR foram avaliadas, em compara o ao espectro do AC de referência. A caracteriza o dos agentes de cura foi feita com a técnica TG/FT-IR do gás liberado de cada SE, em compara o ao espectro de referência do produto de degrada o do respectivo AC.
Idade materna e síndrome de Down no Nordeste do Brasil
Gusm?o, Fábio A. F.;Tavares, Eraldo J. M.;Moreira, Lília Maria de Azevedo;
Cadernos de Saúde Pública , 2003, DOI: 10.1590/S0102-311X2003000400020
Abstract: this study analyzes the association between advanced maternal age and increased incidence of down syndrome in neonates, based on a population sample from the state of bahia in northeast brazil. age of the mothers of 220 down syndrome subjects was investigated, and age distribution was compared to that of the population control group, 220 mothers of subjects without down syndrome. the proportion of down syndrome infants dependent on advanced maternal age was estimated at 43.6%, thus showing a high correlation (r = 0.95) between advanced maternal age and down syndrome incidence. however, this component was significantly lower than the 75% reported in the literature. the component independent of maternal age was estimated at 56.4%, indicating the action of other factors on meiotic non-disjunction associated with 21 trisomy. the results also indicate that despite the regional characteristics of northeast brazil, factors both dependent and independent of maternal age show the same distribution observed in southeast brazil, where extensive studies have been performed.
Idade materna e síndrome de Down no Nordeste do Brasil
Gusm?o Fábio A. F.,Tavares Eraldo J. M.,Moreira Lília Maria de Azevedo
Cadernos de Saúde Pública , 2003,
Abstract: Analisa-se, aqui, a associa o entre idade materna avan ada para procria o e aumento da incidência de progênie com síndrome de Down em amostra populacional do Estado da Bahia. Compararam-se as idades das m es de 220 portadores de síndrome de Down ao grupo-controle composto por m es de mesmo número de nascidos vivos, sem a síndrome de Down. Estimou-se em 43,6% o percentual de síndrome de Down dependente da idade materna indicando uma alta correla o (r = 0,95) entre idade materna e síndrome de Down. Este componente foi, entretanto, significantemente menor do que o percentual de 75% referido na literatura. Estimou-se o componente independente da idade materna em 56,4%, evidenciando a importancia de outros fatores, no processo de n o-disjun o meiótica associada à trissomia 21. Os resultados encontrados mostram também que, n o obstante as características próprias da Regi o Nordeste, os fatores dependentes e independentes da idade materna apresentam a mesma tendência de distribui o observada na Regi o Sudeste do Brasil, onde extensivos estudos têm sido realizados.
First record of Histiotus laephotis Thomas (Chiroptera, Vespertilionidae) from Brazil
Miranda, Jo?o M. D.;Azevedo-Barros, Maria F. M.;Passos, Fernando C.;
Revista Brasileira de Zoologia , 2007, DOI: 10.1590/S0101-81752007000400040
Abstract: the first record of histiotus laephotis thomas, 1916 from brazil is reported here. an adult male was caught with a mist net in a barn located within an araucaria pine forest in the municipality of passos maia, state of santa catarina, southern brazil (26o46'48"s and 52o03'34"w). this record extends the distribution of this species in south america. morphological and taxonomic notes of this species are described as well.
The surface electromyography analysis of the non-plegic upper limb of hemiplegic subjects
Kuriki, Heloyse U;Azevedo, Raquel N. de;Carvalho, Augusto C. de;Azevedo, Fábio Mícolis de;Negr?o-Filho, Rúben F;Alves, Neri;
Arquivos de Neuro-Psiquiatria , 2010, DOI: 10.1590/S0004-282X2010000400016
Abstract: many authors have studied physical and functional changes in individuals post-stroke, but there are few studies that assess changes in the non-plegic side of hemiplegic subjects. this study aimed to compare the electromyographic activity in the forearm muscles of spastic patients and clinically healthy individuals, to determine if there is difference between the non-plegic side of hemiplegics and the dominant member of normal individuals. 22 hemiplegic subjects and 15 clinically healthy subjects were submitted to electromyography of the flexor and extensor carpi ulnaris muscles during wrist flexion and extension. the flexor muscles activation of stroke group (average 464.6 u.n) was significantly higher than the same muscles in control group (mean: 106.3 u.n.) during the wrist flexion, what shows that the non affected side does not present activation in the standart of normality found in the control group.
Avalia??o de um dispositivo portátil para biópsia vácuo-assistida de microcalcifica??es mamárias
Camargo Júnior, Hélio Sebasti?o Amancio de;Camargo, Márcia Martos Amancio de;Teixeira, Sandra Regina Campos;Azevedo, Juliana;Arruda, Maurício de Souza;
Radiologia Brasileira , 2010, DOI: 10.1590/S0100-39842010000200011
Abstract: objective: vacuum-assisted biopsy is the percutaneous technique of breast biopsy with the lowest underestimation rate. however, the cost of such procedure is high and currently there is a considerable interest in developing less expensive techniques. the present study was aimed at testing a less expensive device for vacuum-assisted biopsy of breast microcalcifications. materials and methods: thirty-five patients with clustered microcalcifications classified as bi-rads? 4 or 5 were submitted to biopsy. collected specimen appropriateness, difficulties in the reinsertion of the cannula and number of biopsy passes were evaluated. results: successful specimens collection was achieved in all of the patients. histo-radiological disagreement, difficulties in the cannula reinsertion or severe complications were not observed. conclusion: the authors conclude that the method is effective in terms of specimens appropriateness and cost-benefit ratio as compared with of biopsy techniques for breast microcalcifications. such findings are compatible with data reported in the literature.
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