Water contamination is a major environmental problem in many cities of the world. Most water contamination results from industry and human activities that generate toxic substances (e.g., metals). Rheophilic and aquatic mosses are found in lotic ecosystems, and their morphological and physiological traits are responsive to ecological and pollution gradients. Here we hypothesized that the native rheophilic moss Platyhypnidium aquaticum (A. Jaeger) M. Fleisch exposed to polluted waters can bioaccumulate greater amounts of metals, and a metalloid, than P. aquaticum exposed to pollution-free water. To this aim, we tested the bioindicator capacity of the aquatic P. aquaticum for 15 metals (Cd, Pb, Zn, Fe, K, Ca, Na, Mn, V, Co, Ba, Cr, Al, Sr, and Mg) and one metalloid (As), in twelve river samples coming from three urban and one control zone along the Zamora river in the city of Loja. When compared to the control, our results showed that P. aquaticum in the Southern, Central, and Northern zones of the city bioaccumulated higher concentrations of Ba, Cd, Co, Fe, Mg, Mn, Na, Sr, Zn, and the metalloid As. On the other hand, concentrations of Al, Ca, Cr, Pb, and V in P. aquaticum tended to be lower in the control zone, but these differences were not significant. We suggest that the presence of these contaminants may be related to water pollution (e.g., residual discharges and a lack of treatment systems) along urban zones of the river. We report for the first time the utility of P. aquaticum as a model species for development of long-term biomonitoring programs of water contamination in South America. Passive biomonitoring with P. aquaticum can be a simple and low-cost method to obtain reliable data of the current state of water contamination with metals and metalloids in tropical regions.
The delivery of bioactive compounds is often improved by their encapsulation within systems based on different materials such as polymers and phospholipids. In this regard, one of the most attractive vehicles are liposomes, which can be produced by the self-assembly of phospholipids in aqueous buffered systems. Encapsulation of therapeutic magnetite nanoparticles (MNPs) within liposomes can be accomplished by direct translocation of their lipid bilayer by surface conjugation of potent translocating peptides (and proteins) such as Buforin-II and OmpA. Here, we put forward the notion that to achieve reproducibility and optimize this process, it is possible to develop microfluidic systems that use flow-focusing methods to manipulate the interaction of suspended MNPs (ferrofluids) with the liposomes. With that in mind, we have developed an in silico approach to predict the performance of microfluidic devices specifically designed for the encapsulation process. This was done by running multiphysics simulations in COMSOL to evaluate the macroscopic flow of liposomes and suspended MNPs via a multiphase mixture model. Moreover, we estimated the corresponding interaction using a chemical reaction model based on embedding the Michaelis-Menten equation within the diluted species module's transport. In this case, the enzymes-substrate interaction was considered similar to that of the MNPs-liposome. As a result, we were able to approach saturation kinetics that resembles that obtained experimentally for the uptake of functionalized MNPs. Future work will be directed towards refining the model by considering more details on the possible stages during the interaction of the involved intermediates.
O tabagismo é um dos principais problemas de saúde pública, causando expressivos números de morbidade e mortalidade, estando associado a diversas doenças que acometem tanto o sistema cardiovascular como o respiratório. Desse modo, o marketing de alternativas supostamente mais saudáveis ao tabagismo disparou nos últimos anos, mais especificamente com o advento dos cigarros eletrônicos desde a primeira década do século XXI, também chamados sistemas eletrônicos de liberação de nicotina. Entretanto, é extremamente questionável até que ponto essas alternativas tecnológicas são realmente mais saudáveis que qualquer outra droga baseada em nicotina. Dessa forma, o presente estudo, tem como objetivo analisar e comparar as respostas cardiovasculares e respiratórias após o uso de cigarro eletrônico e cigarro convencional e identificar a possibilidade de afirmar que um dos dispositivos é menos prejudicial à saúde do que o outro. O desenvolvimento desta revisão bibliográfica foi realizado por meio de um levantamento de testes clínicos na base de dados PubMED. Os resultados sugerem que há diferenças no efeito fisiológico de cada tipo de dispositivo, mas ao mesmo tempo evidencia a necessidade de realização de mais ensaios clínicos e estudos para analisar e confirmar os seus efeitos a médio e longo prazo.
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