RESUMO
Spin-transport and current-induced torques in ferromagnet heterostructures given by a ferromagnetic domain wall are investigated. Furthermore, the continuum spin conductivity is studied in a frustrated spin system given by the Heisenberg model with ferromagnetic in-chain interaction [Formula: see text] between nearest neighbors and antiferromagnetic next-nearest-neighbor in-chain interaction [Formula: see text] with aim to investigate the effect of the phase diagram of the critical ion single anisotropy [Formula: see text] as a function of [Formula: see text] on conductivity. We consider the model with the moderate strength of the frustrating parameter such that in-chain spin-spin correlations that are predominantly ferromagnetic. In addition, we consider two inter-chain couplings [Formula: see text] and [Formula: see text], corresponding to the two axes perpendicular to chain where ferromagnetic as well as antiferromagnetic interactions are taken into account.
RESUMO
The estuarine channel of Vitória Bay was evaluated regarding bioaccumulation of metals (Al, Ba, Mn, Fe, Zn, Cu, Cr, Pb, Ni, Cd, Hg) and As in mollusks. Mussels from an aquaculture farm and transplanted into the estuary, whereas oysters were collected in situ in the same area. Concentrations of Al, Mn, Fe, Cr and As were higher in P. perna, whereas C. rhizophorae bioaccumulated more Ba, Zn and Cu. Arsenic concentrations in P. perna exceeded the limit of the Brazilian legislation in the outer estuary. Salinity seemed to influence metal uptake differently for each bivalve, with P. perna absorbing more metal at higher salinities and C. rhizophorae in areas of lower salinity. Hazard index (HI) >1 revealed risk for both bivalves for high level consumers. Target Cancer Risk (TCR) for As revealed threat for human health associated with the consumption of mussels and oysters from the study area.
Assuntos
Arsênio , Crassostrea , Metais Pesados , Perna (Organismo) , Poluentes Químicos da Água , Animais , Baías , Brasil , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análiseRESUMO
Amyloid-ß peptide (Aß) has been shown to cause synaptic dysfunction and can render neurons vulnerable to excitotoxicity and oxidative stress. Na,K-ATPase plays an important role to maintain cell ionic equilibrium and it can be modulated by N-methyl-D-aspartate (NMDA)-nitric oxide (NO)-cyclic GMP pathway. Disruption of NO synthase (NOS) activity and reactive oxygen species (ROS) production could lead to changes in Na,K-ATPase isoforms' activities that may be detrimental to the cells. Our aim was to evaluate the signaling pathways of Aß in relation to NMDA-NOS-cyclic GMP versus oxidative stress on α1-/α2,3-Na,K-ATPase activities in rat hippocampal slices. Aß1-40 induced a concentration-dependent increase of NOS activity and increased cyclic guanosine monophosphate (cGMP), TBARS (thiobarbituric acid reactive substances), and 3-Nitrotyrosine (3-NT)-modified protein levels in rat hippocampal slices. The increase in NOS activity and cyclic GMP levels induced by Aß1-40 was completely blocked by MK-801 (inhibitor of NMDA receptor) and L-NAME (inhibitor of NOS) pre-treatment but changes in TBARS levels were only partially blocked by both compounds. The Aß treatment also decreased Na,K-ATPase activity which was reverted by N-nitro-L-arginine methyl ester hydrochloride (L-NAME) but not by MK-801 pre-treatment. The decrease in enzyme activity induced by Aß was isoform-specific since only α1-Na,K-ATPase was affected. These findings suggest that the activation of NMDA-NOS signaling cascade linked to α2,3-Na,K-ATPase activity may mediate an adaptive, neuroprotective response to Aß in rat hippocampus.
Assuntos
Hipocampo , Estresse Oxidativo , Animais , GMP Cíclico , Maleato de Dizocilpina , N-Metilaspartato , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico , Peptídeos , Ratos , ATPase Trocadora de Sódio-Potássio , Substâncias Reativas com Ácido TiobarbitúricoRESUMO
The three-dimensional Ising model in an external field is used as a mathematical model for price dynamics of financials market. The model allows us to test within the same framework the comparative explanatory power of rational agents versus irrational agents with respect to the stylized facts of the financial markets. We obtain the price dynamics in terms of the strength of the field that reinforces the sensitivity of the agent's sentiment to external news. The exponent of long-tail cumulative probability density is determined and satisfies the inverse of the cubic law. Furthermore, the long range memory of the model is studied using different methods to determine the Hurst index of the model. The results obtained display that the model does serve as a mathematical model for financial markets.
RESUMO
The mussel Perna perna is one of the most used bioindicators of coastal areas and the most economically exploited species in Brazil through mariculture. In the present study, P. perna was used to investigate metal pollution in the estuarine area of Vitória Bay. Four sampling sites were located along an estuarine branch of Vitória Bay and stations were sampled during three campaigns. Trace metals in the tissues of P. perna were evaluated as well as dissolved trace metals and other ancillary variables in the water column. Dissolved Cd, Pb, Cu, Ni, and Fe concentrations surpassed the tolerance limits stablished by legislation in all the sampling campaigns. P. perna exhibited concentrations in disagreement with the Brazilian legislation for Cr and As. A general trend of higher concentrations in outer stations was observed for most metals, what suggested the occurrence of flocculation process in the lower estuary, reducing the concentrations of dissolved elements and increasing their bioavailability for the biota through the particulate form. Cd was highlighted with elevated concentrations in dissolved fraction but not detected in P. perna, probably due to chlor-complex formation under influence of more saline waters. Al, Ba, Mn, Fe, Cu, Zn, Ni, Cr, Pb, and As were considered bioavailable, once they were accumulated in the mussels' tissues. Hazard index (HI) and target cancer risk (TCR) showed that the consumption of mussels from the study area offers health risk issues, being iron and arsenic the main contributors for the high indexes.
Assuntos
Metais Pesados , Poluentes Químicos da Água , Animais , Disponibilidade Biológica , Brasil , Biomarcadores Ambientais , Monitoramento Ambiental , Estuários , Metais Pesados/análise , Poluentes Químicos da Água/análiseRESUMO
A adoção de práticas fraudulentas é comum na cadeia produtiva do mel e está associada à popularidade desse alimento e a dificuldade de detecção da adulteração do produto a olho nu ou por degustação. O objetivo deste trabalho foi verificar se práticas fraudulentas são adotadas em méis comercializados no estado do Pará. Para a realização da pesquisa, 14 amostras comerciais de méis provenientes de 06 (seis) municípios, no estado do Pará foram submetidas às análises Lund, Fiehe, Lugol e melissopalinologia. Os resultados obtidos demostraram que 57,14% das amostras apresentaram alteração do precipitado para reação de Lund, indicando alteração no teor proteico. A coloração o azul intenso na reação de Lugol foi observada em 64,28% das amostras, indicando possível adição de amido. Ainda, 85,71% das amostras analisadas apresentaram mudança de coloração para a reação de Fiehe, indicando alteração no teor de hidroximetilfurfural. O conteúdo polínico foi observado em somente 35,71% das amostras e apenas 2,42% do total das amostras analisadas foram consideradas autenticas mediante as análises realizadas. Concluímos que os testes de autenticidade, quando aplicados em conjunto, foram capazes de detectar fraudes nas mostras de mel comercializadas no estado do Pará e que adulterações nos méis comercialmente disponíveis na região alvo do estudo são uma realidade.
The adoption of fraudulents practices is common in the honey production chain and is associated with the popularity of this food and the difficulty of detecting adulteration of the honey with the naked eye or by tasting. The objective of this work was to verify if fraudulent practices are adopted in honeys sold in the state of Pará. To carry out the research, 14 commercial samples of honeys from 06 (six) municipalities, in the state of Pará, were submitted to Lund, Fiehe, Lugol and melissopalinology. The results obtained showed 57.14% of the samples showed a change in the precipitate for Lund's reaction, indicating a change in protein content. The intense blue staining in the Lugol reaction was observed in 64.28% of the samples, indicating a possible addition of starch. In addition, 85.71% of the samples showed a color change for the Fiehe reaction, indicating a change in the hydroxymethylfurfural content. Pollen content was observed in only 35.71% of the samples and only 21.42% of the total samples analyzed were considered authentic through the analyzes performe. We conclude that the authenticity tests, when applied together, were able to detect fraud in honey samples marketed in the state of Pará and that adulterations in the honey commercially available in the target region of the study are a reality.
Assuntos
Contaminação de Alimentos , Fraude , MelRESUMO
A adoção de práticas fraudulentas é comum na cadeia produtiva do mel e está associada à popularidade desse alimento e a dificuldade de detecção da adulteração do produto a olho nu ou por degustação. O objetivo deste trabalho foi verificar se práticas fraudulentas são adotadas em méis comercializados no estado do Pará. Para a realização da pesquisa, 14 amostras comerciais de méis provenientes de 06 (seis) municípios, no estado do Pará foram submetidas às análises Lund, Fiehe, Lugol e melissopalinologia. Os resultados obtidos demostraram que 57,14% das amostras apresentaram alteração do precipitado para reação de Lund, indicando alteração no teor proteico. A coloração o azul intenso na reação de Lugol foi observada em 64,28% das amostras, indicando possível adição de amido. Ainda, 85,71% das amostras analisadas apresentaram mudança de coloração para a reação de Fiehe, indicando alteração no teor de hidroximetilfurfural. O conteúdo polínico foi observado em somente 35,71% das amostras e apenas 2,42% do total das amostras analisadas foram consideradas autenticas mediante as análises realizadas. Concluímos que os testes de autenticidade, quando aplicados em conjunto, foram capazes de detectar fraudes nas mostras de mel comercializadas no estado do Pará e que adulterações nos méis comercialmente disponíveis na região alvo do estudo são uma realidade.
RESUMO
A adoção de práticas fraudulentas é comum na cadeia produtiva do mel e está associada à popularidade desse alimento e a dificuldade de detecção da adulteração do produto a olho nu ou por degustação. O objetivo deste trabalho foi verificar se práticas fraudulentas são adotadas em méis comercializados no estado do Pará. Para a realização da pesquisa, 14 amostras comerciais de méis provenientes de 06 (seis) municípios, no estado do Pará foram submetidas às análises Lund, Fiehe, Lugol e melissopalinologia. Os resultados obtidos demostraram que 57,14% das amostras apresentaram alteração do precipitado para reação de Lund, indicando alteração no teor proteico. A coloração o azul intenso na reação de Lugol foi observada em 64,28% das amostras, indicando possível adição de amido. Ainda, 85,71% das amostras analisadas apresentaram mudança de coloração para a reação de Fiehe, indicando alteração no teor de hidroximetilfurfural. O conteúdo polínico foi observado em somente 35,71% das amostras e apenas 2,42% do total das amostras analisadas foram consideradas autenticas mediante as análises realizadas. Concluímos que os testes de autenticidade, quando aplicados em conjunto, foram capazes de detectar fraudes nas mostras de mel comercializadas no estado do Pará e que adulterações nos méis comercialmente disponíveis na região alvo do estudo são uma realidade.(AU)
The adoption of fraudulents practices is common in the honey production chain and is associated with the popularity of this food and the difficulty of detecting adulteration of the honey with the naked eye or by tasting. The objective of this work was to verify if fraudulent practices are adopted in honeys sold in the state of Pará. To carry out the research, 14 commercial samples of honeys from 06 (six) municipalities, in the state of Pará, were submitted to Lund, Fiehe, Lugol and melissopalinology. The results obtained showed 57.14% of the samples showed a change in the precipitate for Lund's reaction, indicating a change in protein content. The intense blue staining in the Lugol reaction was observed in 64.28% of the samples, indicating a possible addition of starch. In addition, 85.71% of the samples showed a color change for the Fiehe reaction, indicating a change in the hydroxymethylfurfural content. Pollen content was observed in only 35.71% of the samples and only 21.42% of the total samples analyzed were considered authentic through the analyzes performe. We conclude that the authenticity tests, when applied together, were able to detect fraud in honey samples marketed in the state of Pará and that adulterations in the honey commercially available in the target region of the study are a reality.(AU)
Assuntos
Mel , Contaminação de Alimentos , FraudeRESUMO
For more than three decades, Brazilian Clinical Embryologists have been working without specific regulations and following the standards adopted by other healthcare professionals. This document aims to guide behavior and decision-making, while providing directions to embryologist with the purpose of aiding professionals involved with assisted reproduction procedures and their patients. The Code of Ethics and Conduct is an important breakthrough and the first step toward regulating Clinical Embryology as a profession.
Assuntos
Códigos de Ética , Embriologia , Técnicas de Reprodução Assistida , Embriologia/ética , Embriologia/organização & administração , Embriologia/normas , Humanos , Técnicas de Reprodução Assistida/ética , Técnicas de Reprodução Assistida/normasRESUMO
The aim of the study was to use the comet assay (single-cell gel electrophoresis) and micronucleus test to assess the extent of genomic damage in the whole blood of Dendropsophus minutus from agroecosystems with great use of agrochemicals and to compare the results to those obtained from animals living in unpolluted areas. Our results indicated that specimens of D. minutus collected in perturbed areas exhibited higher amounts of DNA damage in blood cells in comparison to animals from areas free of agricultural activities. The average and standard deviation of all comet assay parameters (tail length, percentage of DNA in the tail, and olive tail moment) and micronuclei frequency were significantly higher in specimens collected in perturbed areas than in the animals from preserved areas. Our study showed that animals from perturbed areas, such as agroecosystems, tend to have higher amounts of DNA damage than animals from reference areas. Moreover, we can conclude that D. minutus tadpoles could be included as a model organism in biomonitoring studies.