Active coating of a water drop by an oil film using a MHz-frequency surface acoustic wave

We employ a millimeter-scale piezoelectric acoustic actuator, which generates MHz-frequency surface acoustic waves (SAWs) in a solid substrate, to actively coat a drop of water by a macroscopic film of silicon oil as a paradigm for a small scale and low power coating system. We build upon previous studies on SAW induced dynamic wetting of a solid substrate, also known as the acoustowetting phenomena, to actively drive a model low surface-energy liquid -- silicon oil -- coat a model liquid object -- a sessile drop of water. The oil film spreads along the path of the propagating SAW and comes in contact with the drop, which is placed in its path. The intensity of the SAW determines the rate and the extent to which a macroscopically thick film of oil will climb over the drop to partially or fully cover its surface. The dynamic wetting of the drop by the oil film is governed by a balance between acoustic, capillary, and gravitational contributions. Introducing a water drop as an object to be coated indicates the opportunity to coat liquid phase objects by employing SAWs and demonstrates that oil films which are actuated by SAWs may traverse curved objects and liquid surfaces

Lack of the serum and glucocorticoid-inducible kinase SGK1 attenuates the volume retention after treatment with the PPARγ agonist pioglitazone

PPARgamma-agonists enhance insulin sensitivity and improve glucose utilization in diabetic patients. Adverse effects of PPARgamma-agonists include volume retention and edema formation. Recent observations pointed to the ability of PPARgamma agonists to enhance transcription of the serum and glucocorticoid-inducible kinase SGK1, a kinase that is genomically upregulated by mineralocorticoids and stimulates various renal channels and transporters including the renal epithelial Na+ channel ENaC. SGK1 has been proposed to mediate the volume retention after treatment with PPARgamma agonists. To test this hypothesis, food containing the PPARgamma agonist pioglitazone (0.02%, i.e., approximately 25 mg/kg bw/day) was administered to gene-targeted mice lacking SGK1 (sgk1-/-, n=12) and their wild-type littermates (sgk1+/+), n=12). According to in situ hybridization, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence, treatment with pioglitazone significantly increased renal SGK1 mRNA and protein expression in sgk1+/+ mice. The treatment increased body weight significantly in both, sgk1+/+ mice (+2.2+/-0.3 g) and sgk-/- mice (+1.3+/-0.2 g), and decreased hematocrit significantly in sgk1+/+ mice (-6.5+/-1.0%) and sgk1-/- mice (-3.1+/-0.6%). Both effects were significantly (p<0.05) more pronounced in sgk1+/+ mice. According to Evans Blue distribution, pioglitazone increased plasma volume only in sgk1+/+ mice (from 50.9+/-3.9 to 63.7+/-2.5 microl/g bw) but not in sgk-/- mice (from 46.8+/-3.8 to 48.3+/-5.2 microl/g bw). Pioglitazone decreased aldosterone plasma levels and blood pressure and increased leptin plasma levels in both genotypes. We conclude that SGK1 contributes to but does not fully account for the volume retention during treatment with the PPARgamma agonist pioglitazone

Titanium dioxide nanoparticles oral exposure to pregnant rats and its distribution

Background: Titanium dioxide (TiO2) nanoparticles are among the most manufactured nanomaterials in the industry, and are used in food products, toothpastes, cosmetics and paints. Pregnant women as well as their conceptuses may be exposed to TiO2 nanoparticles; however, the potential effects of these nanoparticles during pregnancy are controversial, and their internal distribution has not been investigated. Therefore, in this study, we investigated the potential effects of oral exposure to TiO2 nanoparticles and their distribution during pregnancy. TiO2 nanoparticles were orally administered to pregnant Sprague-Dawley rats (12 females per group) from gestation days (GDs) 6 to 19 at dosage levels of 0, 100, 300 and 1000 mg/kg/day, and then cesarean sections were conducted on GD 20. Results: In the maternal and embryo-fetal examinations, there were no marked toxicities in terms of general clinical signs, body weight, food consumption, organ weights, macroscopic findings, cesarean section parameters and fetal morphological examinations. In the distribution analysis, titanium contents were increased in the maternal liver, maternal brain and placenta after exposure to high doses of TiO2 nanoparticles. Conclusion: Oral exposure to TiO2 during pregnancy increased the titanium concentrations in the maternal liver, maternal brain and placenta, but these levels did not induce marked toxicities in maternal animals or affect embryo-fetal development. These results could be used to evaluate the human risk assessment of TiO2 nanoparticle oral exposure during pregnancy, and additional comprehensive toxicity studies are deemed necessary considering the possibility of complex exposure scenarios and the various sizes of TiO2 nanoparticles

Good days, bad days: wind as a driver of foraging success in a flightless seabird, the southern Rockhopper Penguin

Due to their restricted foraging range, flightless seabirds are ideal models to study the short-term variability in foraging success in response to environmentally driven food availability. Wind can be a driver of upwelling and food abundance in marine ecosystems such as the Southern Ocean, where wind regime changes due to global warming may have important ecological consequences. Southern rockhopper penguins ( Eudyptes chrysocome ) have undergone a dramatic population decline in the past decades, potentially due to changing environmental conditions. We used a weighbridge system to record daily foraging mass gain (the difference in mean mass of adults leaving the colony in the morning and returning to the colony in the evening) of adult penguins during the chick rearing in two breeding seasons. We related the day-to-day variability in foraging mass gain to ocean wind conditions (wind direction and wind speed) and tested for a relationship between wind speed and sea surface temperature anomaly (SSTA). Foraging mass gain was highly variable among days, but did not differ between breeding seasons, chick rearing stages (guard and crèche) and sexes. It was strongly correlated between males and females, indicating synchronous changes among days. There was a significant interaction of wind direction and wind speed on daily foraging mass gain. Foraging mass gain was highest under moderate to strong winds from westerly directions and under weak winds from easterly directions, while decreasing under stronger easterly winds and storm conditions. Ocean wind speed showed a negative correlation with daily SSTA, suggesting that winds particularly from westerly directions might enhance upwelling and consequently the prey availability in the penguins' foraging areas. Our data emphasize the importance of small-scale, wind-induced patterns in prey availability on foraging success, a widely neglected aspect in seabird foraging studies, which might become more important with increasing changes in climatic variability

Integrando abordagens de pesquisa e extensão pesqueira para envolver pescadores artesanais na avaliação e no uso voluntário de dispositivos de redução da fauna acompanhante

Orientador: Prof. Dr. Rodrigo Pereira MedeirosDissertação (mestrado) - Universidade Federal do Paraná, Campus Pontal do Paraná - Centro de Estudos do Mar, Programa de Pós-Graduação em Sistemas Costeiros e Oceânicos. Defesa : Pontal do Paraná, 09/09/2022Inclui referênciasResumo: A principal estratégia para reduzir o descarte na pesca de arrasto de camarão tem sido o desenvolvimento e utilização de dispositivos de redução da fauna acompanhante (BRDs). Pesquisas têm-se concentrado no desempenho dos BRD em termos biológicos e tecnológicos, não reconhecendo a importância das dimensões humanas, tais como as percepções dos pescadores. Por outro lado, é necessária uma melhor compreensão da abordagem metodológica que permite aos pescadores a adoção voluntária dos BRDs. Este documento analisou o desempenho dos BRD através de uma combinação de atividades de interação e experiências científicas convencionais. Foram realizadas quatro atividades de interação com pescadores de arrasto de camarão de 12 localidades pesqueiras no litoral do Paraná, sul do Brasil. Adaptado de pesquisas anteriores e após sugestão dos pescadores nas atividades de extensão, foi testada uma grelha Nordmored para avaliar as diferenças de uma rede comum no peso do camarão (Xiphopenaeus kroyeri) e das capturas acessórias, e o comprimento total de X. kroyeri. As atividades de interação enfatizaram a importância do diálogo e da participação e mostraram que a percepção dos pescadores envolvia uma diversidade de parâmetros, expandindo a compreensão do desempenho do BRD. Além disso, a abordagem metodológica proporcionou espaço para a aprendizagem coletiva e o envolvimento dos pescadores, com registros de iniciativas voluntárias para reduzir os descartes. Os resultados mostraram que o diálogo é melhorado com a diversificação e integração dos métodos de comunicação, bem como o tempo é crucial para os pescadores processarem informação e construírem conhecimentos. Uma análise da abordagem metodológica utilizada no presente documento fornece informações sobre a forma de aumentar a adoção voluntária de BRD, bem como de envolver os pescadores de forma mais consistente como protagonistas da gestão para uma pesca responsável.Abstract: The main strategy for reducing discards in shrimp trawl fisheries has been the development and use of bycatch reduction devices (BRDs). Research has focused on the performance of BRD in biological and technological terms, undermining the importance of the human dimensions, such as fishers' perceptions. On the other hand, a better comprehension of which methodological approach enables fishers volunteer adoption of BRDs is required. This paper analyzed the performance of BRD through a combination of interaction activities and conventional scientific experiments. Four interaction activities were conducted with shrimp trawlers from 12 fishing sites at the coast of Paraná, South Brazil. Adapted from previous research and after fishers' suggestion in the interaction activities, a Nordmored grid was tested against a control net to evaluate differences in shrimp (Xiphopenaeus kroyeri) and bycatch weight, and total length of X. Kroyeri. Interaction activities stressed the importance of dialogue and participation and showed that fishers perceived a high diversity of parameters, expanding the understanding of BRD performance. Also, the methodological approach provided room for collective learning and fishers' engagement, with reports of voluntary initiatives to reduce bycatch. The results showed that the dialog is improved with diversification and integration of communication methods, as well as timing is crucial for fishers to process information and to build knowledge. An analysis of the methodological approach used in this paper provide insights on how to increase voluntary BRD adoption as well as to engage fishers more consistently in being stewards for the responsible fishing