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Search Results: 1 - 10 of 557599 matches for " Claudia A. F. Aiub "
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Preliminary Study by Environmental Indicator Measurements of Sediments in a Mangrove Forest in Ilha Grande Bay, Rio de Janeiro, Southeastern Brazil  [PDF]
Ana Maria A. Velho, Claudia A. F. Aiub, José L. Mazzei, Sérgio M. Corrêa, Mário L.G. Soares, Israel Felzenszwalb
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.38087
Abstract: Mangroves perform essential functions in biological cycles and are protected by law in Brazil. However, they are being degraded above their support limit, leading to a reduction in the areas around the world. The area investigated in the present study is a potentially unpolluted mangrove ecosystem in the south of Rio de Janeiro state, Brazil. The aim of this work was to investigate the presence of metals and polycyclic aromatic hydrocarbons (PAHs) in mangrove sediment and to correlate them with mutagenic and genotoxic activity. Four seasonal samplings undertaken between 2009 and 2010 at five sites were analyzed. Dichloromethane extracts were obtained under sonication and subjected to mutagenicity assays using Salmonella microsuspension. Metal (Cd, Cr, Cu, Ni and Pb) contents were determined by atomic absorption spectrometry, while the quantification of PAHs was performed by gas chromatography-mass spectrometry. Goniopsis cruentata hemocytes were used to assess potential genotoxic damage (Micronucleus assay). The absence of mutagenicity was observed for all samples using Salmonella typhimurium strains TA97, TA98, TA100 and TA102, in the absence and presence of an exogenous mammalian metabolizing system. Among the metals, Cd and Cu were detected in autumn at values exceeding the threshold effect level and below the probable effect level. Benzo[a] pyrene was detected at levels above the threshold at one site, where small effects could be observed in the biota. Significant differences in the micronucleated cells observed suggest DNA damage had been induced by the PAHs identified.
Ability of Allium cepa L. root tips and Tradescantia pallida var. purpurea in N-nitrosodiethylamine genotoxicity and mutagenicity evaluation
Rainho, Claudia R. de;Kaezer, Andréa;Aiub, Claudia A.F.;Felzenszwalb, Israel;
Anais da Academia Brasileira de Ciências , 2010, DOI: 10.1590/S0001-37652010000400015
Abstract: n-nitroso compounds, such as n-nitrosodiethylamine (ndea), can be formed by the reaction of secundary amines with nitrosating agents, and are suspected to be involved in tumors in humans. ndea has been considered a weak carcinogen in genotoxic assays probably due to the inefficient nitrosamine activation system that is used and/or to the efficient repair system. in this work, we evaluated the sensibility of allium cepa l. root tips and tradescantia stamen hair mutation assay (trad-sh) using tradescantia pallida var. purpurea for ndea (0.1; 0.5; 5 and 25mm) genotoxicity and mutagenicity induction. allium cepa l. was treated with different ndea concentrations for 3h, for 3 consecutive days, including negative control (distilled water) and positive control maleic hydrazide (mh 30mg/ml). after treatment, the roots were hydrolyzed, squashed, and the mitotic index (mi) and cytological abnormalities were scored. the results revealed a cytostatic effect of ndea (0.5 and 5mm), showing a significant reduction in the mi. chromosome stickiness suggests a ndea toxic effect. t. pallida purpurea did not respond to mutagens with a dose-dependent pattern. in conclusion, our study indicates that the root tips of allium cepa l. have sensibility to detect ndea genotoxicity, but not for trad-sh test.
N–nitrosodiethylamine cytochrome P450 induction and cytotoxicity evaluation in primary cultures of rat hepatocytes  [PDF]
Claudia Alessandra Fortes Aiub, Gabriele Gadermaier, Fátima Ferreira, Israel Felzenszwalb, Peter Eckl, Luis Felipe Ribeiro Pinto
American Journal of Molecular Biology (AJMB) , 2011, DOI: 10.4236/ajmb.2011.12009
Abstract: The primary routes of potential human exposure to N-nitrosodiethylamine (NDEA) are ingestion, inhalation, and dermal contact. Air, diet and smoking contribute to potential human exposure at levels of a few µg of NDEA/day. Potential exposure depends on the ability of the nitrosamines to migrate from the product into the body. The first step in the metabolic degradation of NDEA by cytochrome oxidase (CYPs) enzymes is the introduction of a hydroxyl group and in human esophage and liver CYP2A3 and CYP2E1 participate on this metabolism. Measuring cytotoxicity in female rat primary hepatocytes cultures, were used to understand the CYP induction and metaboli-zation correlated with low NDEA concentrations. We observed that NDEA at different concentrations in the absence of CYPs inducers, was able to induce CYP2B1, CYP2B2, CYP2E1, CYP3A1 and CYP4A3. A positive NDEA synergistic effect on the levels of mRNA, was observed in the presence of pyrazole (300 µM) for CYP2B1 and CYP2B2 and for pregnenolone 16- carbonitrile (0.15 µM) for CYP2E1. Negative NDEA synergistic effects were observed for ethanol (0.3%) for CYP3A1, pyrazol (300 µM) for CYP2A1 and CYP2E1, and phenobarbital (1 mM) for CYP2A1. These facts are extremally important once that these metabolites can be directly related to the primary DNA lesions. We consider that studies to elucidate the biological factors that determine the shape of the dose-response curve are crucial for low-dose extrapolations of risk.
Evaluation of Brazilian medical devices using agar diffusion cytotoxicity assay
Vidal, Mirian N. P.;Aiub, Claudia;Abrantes, Shirley;Zamith, Helena P. S.;
Revista Brasileira de Hematologia e Hemoterapia , 2009, DOI: 10.1590/S1516-84842009000200009
Abstract: over the last decades, governmental actions and mechanisms created to protect consumer rights have been linked to a growing effort to guarantee the quality and reliability of products. samples of condoms (latex), medical devices and blood bags (pvc - polyvinyl chloride) have been tested using the agar diffusion assay. this assay evaluates the cytotoxicity induced by biomaterials by measuring the biological reactivity of mammalian cell cultures in contact with these materials. pvc is used in the production of medical devices because of its specific properties, such as flexibility, obtained after the addition of plasticizers (phthalates), which can cause toxicity even at low doses. latex is a natural elastomer used for surgical gloves and condoms with a formulation that includes dispersion of liquid latex and chemicals, such as antioxidants and a vulcanizing accelerator, both of which are able to induce cytotoxicity. samples were analyzed by the national institute of quality control in health - incqs of the oswaldo cruz foundation (fiocruz) in accordance with the governmental sanitary surveillance actions on respect to the quality control. we observed an increase in the quality of the products in relation to the results of the agar diffusion assay during the period between 2000 and 2007. this situation, together with other actions, reflects in an improvement in the quality of products that can be translated in the health of the population.
Bustos,Claudia A; Landaeta,Mauricio F;
Gayana (Concepción) , 2005, DOI: 10.4067/S0717-65382005000200016
Abstract: the embryonic and early larval development of the southern hake, merluccius australis, is described for the first time using laboratory reared specimens. the eggs are pelagic, measure 0.9-1.1 mm diameter, have smooth chorion, unsegmented yolk and one 0.19-0.27 mm diameter oil globule. at a temperature of 11.5 oc the larvae hatch 7 days after fertilization, at an average size of 2.8 mm nl (notochord length); yolk reserves are exhausted in 9 days. yolk-sac larvae grow at a linear rate of 0.15 mm/day. growth rate is reduced to 0.08 mm/day from first feeding to 45 days (multiple slope test, p < 0.001)
Blindagem eletromagnética, aterramento e prote??o contra surtos de tens?o em equipamentos para monitoramento automático do teor de água no solo
Teixeira, Claudia F. A.;Moraes, Sergio O.;
Engenharia Agrícola , 2004, DOI: 10.1590/S0100-69162004000100027
Abstract: the objective of this paper was to implement an electromagnetic shielding, grounding and voltage surge protection in equipments for automatic soil water monitoring. the experiment was carried out in piracicaba, s?o paulo state, brazil, using a tektronix cable tester (model 1502 b) that operates by time domain reflectometry (tdr) and a datalogger (cr10x, campbell scientific inc., csi) to control and analyze the waveforms produced by the cable tester. the water content was indirectly obtained by measuring the dielectric constant through probes inserted in the soil. for electromagnetic shielding the energy and signal cables were inserted in galvanized pipes, linked together by means of copper wire fixed in the pipes by bimetallic conectors. for the grounding, the copper wire was linked to copperweld stems, making a good contact bettween system and soil. to complete the electro-electronic protection, the powering of the tdr and datalogger was carried out by independent circuit with a proper disruptor, surge protection and no-break unity. the proposed system layout, which made use of preexisting materials as much as possible, presented an effective protection.
Claudia A Bustos,Mauricio F Landaeta
Gayana (Concepción) , 2005,
Abstract: Se describe por primera vez el desarrollo embrionario y larval temprano de la merluza del sur, Merluccius australis, utilizando ejemplares cultivados en el laboratorio. Los huevos miden 0,9-1,1 mm de diámetro, tienen corion liso, vitelo no segmentado y presentan 1 gota oleosa de 0,19-0,27 mm de diámetro. Las larvas mantenidas a 11,5 oC eclosionan 7 días después de la fertilización con un tama o promedio 2,8 mm LN (longitud notocordal); el vitelo se absorbe completamente en 9 días. Las larvas con saco vitelino crecen a una tasa lineal de 0,15 mm/día. El crecimiento se reduce significativamente (test de pendientes múltiples, p < 0,001) a 0,08 mm/día, desde la primera alimentación hasta los 45 días de vida The embryonic and early larval development of the southern hake, Merluccius australis, is described for the first time using laboratory reared specimens. The eggs are pelagic, measure 0.9-1.1 mm diameter, have smooth chorion, unsegmented yolk and one 0.19-0.27 mm diameter oil globule. At a temperature of 11.5 oC the larvae hatch 7 days after fertilization, at an average size of 2.8 mm NL (notochord length); yolk reserves are exhausted in 9 days. Yolk-sac larvae grow at a linear rate of 0.15 mm/day. Growth rate is reduced to 0.08 mm/day from first feeding to 45 days (multiple slope test, p < 0.001)
Behavioral Responses to Inequity in Reward Distribution and Working Effort in Crows and Ravens
Claudia A. F. Wascher, Thomas Bugnyar
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056885
Abstract: Sensitivity to inequity is considered to be a crucial cognitive tool in the evolution of human cooperation. The ability has recently been shown also in primates and dogs, raising the question of an evolutionary basis of inequity aversion. We present first evidence that two bird species are sensitive to other individuals' efforts and payoffs. In a token exchange task we tested both behavioral responses to inequity in the quality of reward (preferred versus non-preferred food) and to the absence of reward in the presence of a rewarded partner, in 5 pairs of corvids (6 crows, 4 ravens). Birds decreased their exchange performance when the experimental partner received the reward as a gift, which indicates that they are sensitive to other individuals' working effort. They also decreased their exchange performance in the inequity compared with the equity condition. Notably, corvids refused to take the reward after a successful exchange more often in the inequity compared with the other conditions. Our findings indicate that awareness to other individuals' efforts and payoffs may evolve independently of phylogeny in systems with a given degree of social complexity.
Heart Rate during Conflicts Predicts Post-Conflict Stress-Related Behavior in Greylag Geese
Claudia A. F. Wascher,Orlaith N. Fraser,Kurt Kotrschal
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015751
Abstract: Social stressors are known to be among the most potent stressors in group-living animals. This is not only manifested in individual physiology (heart rate, glucocorticoids), but also in how individuals behave directly after a conflict. Certain ‘stress-related behaviors’ such as autopreening, body shaking, scratching and vigilance have been suggested to indicate an individual's emotional state. Such behaviors may also alleviate stress, but the behavioral context and physiological basis of those behaviors is still poorly understood.
Efectos ambientales sobre la variabilidad espacial del ictioplancton de Chile austral durante noviembre de 2005
Revista chilena de historia natural , 2008, DOI: 10.4067/S0716-078X2008000200005
Abstract: the distribution and abundance of ichthyoplankton from southern chile (41-45°s) during november 2005 were analyzed, in relation to the oceanographic features of the water column (temperature, salinity, stratification). during the sampling period, 44.606 fish eggs and 2.016 fish larvae were collected, belonging to 28 taxa. early life stages of small pelagic fishes dominated the plankton samples, with mean densities of ~ 14,000 eggs 10 m-2 of anchovy (engraulis ringens) and > 100 larvae 10 m-2of clupleids. multivariate analysis showed the conformation of two groups of stations, one associated to deeper fjord áreas, with strong vertical gradients of temperature and salinity, and higher stratification. the other group was associated to the shallow and well-mixed eastern border of chiloé island. in áreas with strong stratification (le., higher brunt-váisála frequency, n2), significant higher densities of pelagic and mesopelagic fish eggs and larvae were collected (le., strangomera bentincki, maurolicus parvipinnis). comparing these results with an oceanographic cruise carried out 10 years before in the same área (october 1995), changes in the ichthyoplankton composition were detected; this may be caused by potential differences in the marine fish species which utilize fjords and channels of southern chile as spawning and early nursery zone.
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