Ontogenetic foraging activity and feeding selectivity of the Brazilian endemic parrotfishScarus zelindae

Parrotfish are fundamental species in controlling algal phase-shifts and ensuring the resilience of coral reefs. Nevertheless, little is known on their ecological role in the south-western Atlantic Ocean. The present study analysed the ontogenetic foraging activity and feeding selectivity of the Brazilian endemic parrotfish Scarus zelindae using behavioural observation and benthic composition analyses. We found a significant negative relationship between fish size and feeding rates for S. zelindae individuals. Thus, terminal phase individuals forage with lower feeding rates compared to juveniles and initial phase individuals. The highest relative foraging frequency of S. zelindae was on epilithic algae matrix (EAM) with similar values for juveniles (86.6%), initial phase (88.1%) and terminal phase (88.6%) individuals. The second preferred benthos for juveniles was sponge (11.6%) compared with initial (4.5%) and terminal life phases (1.3%). Different life phases of S. zelindae foraged on different benthos according to their availability. Based on Ivlev's electivity index, juveniles selected EAM and sponge, while initial phase and terminal phase individuals only selected EAM. Our findings demonstrate that the foraging frequency of the endemic parrotfish S. zelindae is reduced according to body size and that there is a slight ontogenetic change in feeding selectivity. Therefore, ecological knowledge of ontogenetic variations on resource use is critical for the remaining parrotfish populations which have been dramatically reduced in the Southwestern Atlantic Ocean

EVALUATION OF HUMAN EXPOSURE TO HEXACHLOROBENZENE AT SAMARITÁ, SÃO VICENTE, SÃO PAULO, BRAZIL

Na área de Samaritá, cidade de São Vicente, São Paulo, Brasil, resíduos químicos industriais foram descartados por vários anos, sem proteção ambiental, contendo 55 a 85% de hexaclorobenzeno (HCB) e outros produtos em menores quantidades. Para avaliar o impacto à saúde foram analisados soro sangüíneo de 234 pessoas de diversos bairros da região, com mais de 2 anos de residência, subdivididos em 6 setores: A - Quarentenário e vizinhança do lixo industrial a 67 km; B - Jardim Rio Branco; C - Parque das Bandeiras; D - Gleba II; E - Vila Samaritá; F - Vila Ema, Vila Iolanda, Vila Mathias. Dez amostras de soro sangüíneo de habitantes de Itanhaém, área considerada não exposta, foram coletados para fornecer dados de referência. HCB não foi encontrado em nenhuma destas amostras. Resíduos de HCB foram analisados por cromatografia a gás com detetor de captura de elétrons e limite de determinação de 0,02 µg/dL. Os níveis médios de HCB no soro sanguíneo dos moradores mostraram-se significativamente diferentes (p < 0.001) entre o setor A (0.41µg/dL) e os demais setores: B (0.04 µg/dL); C (0.04 µg/ dL); D (0.03 µg/dL); E (0.04 µg/dL): F (0.04 µg/dL). Ainda que não seja possível estabelecer correlações com doenças encontradas na população, este estudo demonstra que os resíduos de HCB constituem problema para a saúde, pois além de contaminar o meio ambiente são encontrados em seres vivos, inclusive no ser humano. Abstract In the Samaritá area of São Vicente city, São Paulo State, Brazil, a chemical industry discarded for several years, with no environmental protection, a mixture of residues containing 55 to 85% of hexachlorobenzene (HCB) and others in smaller quantities. In order to evaluate the impact of these residues on the health of the local population, blood serum samples taken from 234 people dwelling at several quarters of this area for over two years were analyzed, divided into 6 sectors: A - Quarentenário and neighborhood of the industrial wastes dump at 67-km; B - Jardim Rio Branco; C - Parque das Bandeiras; D - Gleba II; E -Vila Samaritá; F -Vila Ema, Vila Iolanda, Vila Mathias. Ten blood samples from residents of an area considered no exposed from Itanhaém city were collected to provide baseline information and HCB was not found in any of the samples. HCB residues were analysed by gas chromatography with an electron capture detector, with a determination limit of 0.02 µg/dL. The mean of HCB in blood serum for the inhabitants of the affected area presented significant differences (p < 0.001) between sector A (0.41 µg/dL) and all the others sectors: B (0.04 µg/dL); C (0.04 µg/ dL); D (0.03 µg/dL); E (0.04 µg/dL): F (0.04 µg/dL). Although it has not yet been possible to correlate such findings with the presence of diseases among the area inhabitants, this study indicates that the HCB residues are a health risk, as they not only contaminate the environment, but are also present at the biota, including humans

ASPECTOS REPRODUTIVOS DO PEIXE-ZEBRA, Danio rerio, EXPOSTO A DOSES SUBLETAIS DE DELTAMETRINA

The deltamethrin is listed by the Environmental Protection Agency of the United States (USEPA) as a possible endocrine disruptor, being able to interfere in the reproductive system. It is a synthetic pyrethroid, with potent insecticide action, relatively low toxicity in mammals and limited persistence in the environment, but high toxic to aquatic organisms. It is also used in the human and veterinary medicines for prophylaxis and treatment of parasitic diseases. The aim of this study was to evaluate possible endocrine alterations in the reproduction of the zebrafish (Danio rerio) following the protocol of USEPA (2002). The fish were exposed to sublethal concentrations of deltamethrin (6 µg/L and 10 µg/L of the technical deltamethrin) and acetone, used as solvent, during 14 days. Parameters as number of eggs, hatching, size and histology of the gonads were evaluated. It was not observed any significant difference of the evaluated parameters among the groups. The deltamethrin didnt alter the reproduction of the zebrafish. In the present study the progeny was not evaluated, because was not included in the used protocol. However, endocrine disruptor substances can affect the neuroendocrine reproductive system and the alterations can appear in the progenitors or in the progeny in different stages of the development.A deltametrina está listada pela Agência de Proteção Ambiental dos Estados Unidos (USEPA) como possível desregulador endócrino, podendo, portanto, interferir no sistema reprodutivo. É um piretróide sintético, com ação inseticida, toxicidade relativamente baixa para mamíferos e persistência limitada no meio ambiente, mas de alta toxicidade para organismos aquáticos. É também empregada nas medicinas humana e veterinária para profilaxia e tratamento de doenças parasitárias. O objetivo deste estudo foi avaliar possíveis alterações na reprodução do peixe zebra (Danio rerio) seguindo o protocolo da USEPA (2002). Os peixes foram expostos a concentrações subletais de deltametrina (6 µg/L e 10 µg/L) e à acetona (solvente), durante 14 dias. Parâmetros como número de ovos, eclosão, índice gônado-somático e histologia de gônadas foram avaliados. Não foi possível observar nenhuma diferença significativa dos parâmetros avaliados entre os grupos, concluindo-se que a deltametrina não alterou a reprodução da espécie estudada. Neste trabalho a progênie não foi avaliada, pois não fazia parte do protocolo proposto. Porém, as substâncias desreguladoras endócrinas podem atuar afetando o sistema neuroendócrino reprodutivo e estas alterações podem apresentar-se tanto nos progenitores como na progênie em diferentes etapas do desenvolvimento

Microstructure and mechanical behavior of similar butt-joints of ZK60 and ZK60–1.5RE magnesium alloys produced by linear friction stir welding

The microstructure and mechanical properties of butt-joints produced by linear friction stir welding of similar plates of as-cast ZK60 and modified ZK60 with 1.5 wt.% RE (ZK60–1.5RE) are investigated. The thermomechanical affected zone is investigated in both advancing and retrieving sides, and the microstructure is compared to the base metal and the stirred zone. Electron backscattered diffraction measurements provide the average microstructural features of the transformed microstructure. The mechanical properties are assessed using hardness, tensile testing, and surface residual stress measured using X-ray diffraction. Higher torque and heat input are obtained for the ZK60–1.5RE compared to the ZK60. The thermomechanical affected zone is notably larger for the ZK60 compared to the ZK60–1.5RE. A gradient microstructure is formed in thermomechanical affected zones where deformed grains are progressively more recrystallised towards the stirred zone. There is no visible interface between the thermomechanical affected zone and the stirred zone. A fine and partially recrystallised microstructure is formed in the stirred zone. The retrieving side of the ZK60–1.5RE has a slightly more refined microstructure compared to the other investigated zones. Anisotropy measured with increment in the maximum intensity of the (0001) increases towards to stirred zone. The formed microstructure is correlated with the role of twinning, recovery, static, and dynamic recrystallisation that can occur during friction stir welding. Twinning and grains with large misorientation spread are more pronounced in the thermomechanical affected zone and regions towards the base metal. Sharp low angle grain boundaries are observed towards the stirred zone. From refined recrystallised grains decorating the grain in the thermomechanical affected zone, a mosaic-like of low and high angle grain boundaries are observed in the stirred zone. The joints have comparable surface residual stresses. The friction stir welding improved the ductility and strength of the as-cast ZK60–1.5RE alloy since the tensile samples fractured in the BM

Design of a nanostructured mucoadhesive system containing curcumin for buccal application : from physicochemical to biological aspects

Mucoadhesive nanostructured systems comprising poloxamer 407 and Carbopol 974P® have already demonstrated good mucoadhesion, as well as improved mechanical and rheological properties. Curcumin displays excellent biological activity, mainly in oral squamous cancer; however, its physicochemical characteristics hinder its application. Therefore, the aim of this study was to develop nanostructured formulations containing curcumin for oral cancer therapy. The photophysical interactions between curcumin and the formulations were elucidated by incorporation kinetics and location studies. They revealed that the drug was quickly incorporated and located in the hydrophobic portion of nanometer-sized polymeric micelles. Moreover, the systems displayed plastic behavior with rheopexy characteristics at 37 °C, viscoelastic properties and a gelation temperature of 36 °C, which ensures increased retention after application in the oral cavity. The mucoadhesion results confirmed the previous findings with the nanostructured systems showing a residence time of 20 min in porcine oral mucosa under flow system conditions. Curcumin was released after 8 h and could permeate through the porcine oral mucosa. Cytotoxicity testing revealed that the formulations were selective to cancer cells over healthy cells. Therefore, these systems could improve the physicochemical characteristics of curcumin by providing improved release and permeation, while selectivity targeting cancer cells

Effect of Ce-base mischmetal addition on the microstructure and mechanical properties of hot-rolled ZK60 alloy

Mg-Zn-Zr (ZK) alloys exhibit notably high mechanical strength amongst all magnesium alloy grades. However, due to the formation of low melting point Mg3Zn7-precipitates, these alloys are susceptible to hot cracking, thus compromising their metallurgical processing. The addition of rare earths to ZK alloys is an alternative to form higher melting point intermetallic compounds, speed up dynamic recrystallization, refine grain size, enhance corrosion resistance and extend the service temperature due to improved creep resistance. This work deals with the effect of Ce-base mischmetal addition on the hot rolling behaviour of as-cast ZK60 alloy. The microstructure investigation conducted using electron microscopy and X-Ray diffraction shows that precipitation of Mg7Zn3 intermetallics occur during hot rolling, whereas no further precipitation is observed for the ZK60-Mm alloys. The fragmentation of the intermetallic compounds occur during hot rolling and finer particles of Mg7Zn3 are observed for the ZK60, whereas Mg7Zn3 and MgZn2Ce intermetallics are formed in the alloy modified with mischmetal addition. A higher fraction of dynamically recrystallized grains is observed for the ZK60-Mm in comparison to the ZK60. Continuous recrystallization takes place in ZK60 with the formation of sub-grains near to the intermetallics and the addition of mischmetal promotes the occurrence of discontinuous recrystallization with the nucleation of new grains close to the precipitates. The mechanical strength and, in particular, the ductility of the hot-rolled alloys are notably improved when compared to the same alloys in the as-cast condition. The mechanical strength is, however, higher for the ZK60 alloy. Less solid solution strengthening, softer MgZn2Ce intermetallics and more extensive recrystallization contribute to reduce the mechanical strength of ZK60-Mm. Failure in both alloys are initiated at coarse intermetallics and propagate through intermetallic-rich regions

Evaluation of cardiovascular risk factors in the Wistar Audiogenic Rat (WAR) Strain

Introduction: Risk factors for life-threatening cardiovascular events were evaluated in an experimental model of epilepsy, the Wistar Audiogenic Rat (WAR) strain. Methods: We used long-term ECG recordings in conscious, one year old, WAR and Wistar control counterparts to evaluate spontaneous arrhythmias and heart rate variability, a tool to assess autonomic cardiac control. Ventricular function was also evaluated using the pressure-volume conductance system in anesthetized rats. Results: Basal RR interval (RRi) was similar between WAR and Wistar rats (188\ub15 vs 199\ub16 ms). RRi variability strongly suggests that WAR present an autonomic imbalance with sympathetic overactivity, which is an isolated risk factor for cardiovascular events. Anesthetized WAR showed lower arterial pressure (92\ub13 vs 115\ub15 mmHg) and exhibited indices of systolic dysfunction, such as higher ventricle end-diastolic pressure (9.2\ub10.6 vs 5.6\ub11 mmHg) and volume (137\ub19 vs 68\ub19 \u3bcL) as well as lower rate of increase in ventricular pressure (5266\ub1602 vs 7320\ub1538 mmHg.s-1). Indices of diastolic cardiac function, such as lower rate of decrease in ventricular pressure (-5014\ub1780 vs -7766\ub1998 mmHg.s-1) and a higher slope of the linear relationship between end-diastolic pressure and volume (0.078\ub10.011 vs 0.036\ub10.011 mmHg.\u3bcL), were also found in WAR as compared to Wistar control rats. Moreover, Wistar rats had 3 to 6 ventricular ectopic beats, whereas WAR showed 15 to 30 ectopic beats out of the 20,000 beats analyzed in each rat. Conclusions: The autonomic imbalance observed previously at younger age is also present in aged WAR and, additionally, a cardiac dysfunction was also observed in the rats. These findings make this experimental model of epilepsy a valuable tool to study risk factors for cardiovascular events in epilepsy