Polystyrene (PS) is one of the main synthetic polymers produced around the world, and it is present in the composition of a wide variety of single-use objects. When released into the environment, ...these materials are degraded by environmental factors, resulting in microplastics. We investigated the ability of Chironomus sancticaroli (Diptera, Chironomidae) to promote the fragmentation of PS microspheres (24.5 ± 2.9 μm) and the toxic effects associated with exposure to this polymer. C. sancticaroli larvae were exposed to 3 different concentrations of PS (67.5, 135, and 270 particles g–1 of dry sediment) for 144 h. Significant lethality was observed only at the highest concentration. A significant reduction in PS particle size as well as evidence of deterioration on the surface of the spheres, such as grooves and cracks, was observed. In addition, changes in oxidative stress biomarkers (SOD, CAT, MDA, and GST) were also observed. This is the first study to report the ability of Chironomus sp. to promote the biofragmentation of microplastics. The information obtained demonstrates that the macroinvertebrate community can play a key role in the degradation of plastic particles present in the sediment of freshwater environments and can also be threatened by such particle pollution.
HVDC has been chosen as an economical and technical solution for power transmission through long distances, asynchronous interconnections and long submarine cables crossing. Despite DC transmission ...benefits to power systems, the converters non-linearity produces undesirable effects to the converter transformer in service, mainly listed in the technical standard IEC/IEEE 60076-57-129. However, additional discussions and complementary information can be found in a plurality of references, which are brought in the article under a comprehensive overview perspective. Some design solutions deal with these effects increasing the technical margins, which have direct influence on manufacturing costs and transformer reliability and availability levels. This article goes through the main topics pointed by the standard and the references, investigating their consequences in the converter transformer operation, in order to provide a comprehensive tutorial on design solutions and considerations to deal with those undesirable effects.
Online learning has grown in recent years and has become popular with Massive Open Online Courses (MOOCs). The advent of the pandemic has undoubtedly made more teachers and students experience the ...online learning experience. Distance learning is going to grow even more in the coming years. In this article, we present our computational thinking and programming course focused on life science students. We introduce our approach for analyzing how students interact with didactic resources regarding their probability of completing the course. We discussed several insights this strategy brought us and how we can leverage the teaching of programming skills to life science students through learning analytics. We suggest that machine learning techniques will be increasingly essential for better monitoring and supporting students and for online courses improvements.
Abstract The Nobel Prize in Chemistry 2019 recognized the importance of Li-ion batteries and the revolution they allowed to happen during the past three decades. They are part of a broader class of ...electrochemical energy storage devices, which are employed where electrical energy is needed on demand and so, the electrochemical energy is converted into electrical energy as required by the application. This opens a variety of possibilities on the utilization of energy storage devices, beyond the well-known mobile applications, assisting on the decarbonization of energy production and distribution. In this series of reviews in two parts, two main types of energy storage devices will be explored: electrochemical capacitors (part I) and rechargeable batteries (part II). More specifically, we will discuss about the materials used in each type of device, their main role in the energy storage process, their advantages and drawbacks and, especially, strategies to improve their performance. In the present part, electrochemical capacitors will be addressed. Their fundamental difference to batteries is explained considering the process at the electrode/electrolyte surface and the impact in performance. Materials used in electrochemical capacitors, including double layer capacitors and pseudocapacitive materials will be reviewed, highlighting the importance of electrolytes. As an important part of these strategies, synthetic routes for the production of nanoparticles will also be approached (part I).
The initiation of translation in eukaryotes is supported by the action of several eukaryotic Initiation Factors (eIFs). The largest of these is eIF3, comprising of up to thirteen polypeptides (eIF3a ...through eIF3m), involved in multiple stages of the initiation process. eIF3 has been better characterized from model organisms, but is poorly known from more diverged groups, including unicellular lineages represented by known human pathogens. These include the trypanosomatids (Trypanosoma and Leishmania) and other protists belonging to the taxonomic supergroup Excavata (Trichomonas and Giardia sp.).
An in depth bioinformatic search was carried out to recover the full content of eIF3 subunits from the available genomes of L. major, T. brucei, T. vaginalis and G. duodenalis. The protein sequences recovered were then submitted to homology analysis and alignments comparing them with orthologues from representative eukaryotes. Eleven putative eIF3 subunits were found from both trypanosomatids whilst only five and four subunits were identified from T. vaginalis and G. duodenalis, respectively. Only three subunits were found in all eukaryotes investigated, eIF3b, eIF3c and eIF3i. The single subunit found to have a related Archaean homologue was eIF3i, the most conserved of the eIF3 subunits. The sequence alignments revealed several strongly conserved residues/region within various eIF3 subunits of possible functional relevance. Subsequent biochemical characterization of the Leishmania eIF3 complex validated the bioinformatic search and yielded a twelfth eIF3 subunit in trypanosomatids, eIF3f (the single unidentified subunit in trypanosomatids was then eIF3m). The biochemical data indicates a lack of association of the eIF3j subunit to the complex whilst highlighting the strong interaction between eIF3 and eIF1.
The presence of most eIF3 subunits in trypanosomatids is consistent with an early evolution of a fully functional complex. Simplified versions in other excavates might indicate a primordial complex or secondary loss of selected subunits, as seen for some fungal lineages. The conservation in eIF3i sequence might indicate critical functions within eIF3 which have been overlooked. The identification of eIF3 subunits from distantly related eukaryotes provides then a basis for the study of conserved/divergent aspects of eIF3 function, leading to a better understanding of eukaryotic translation initiation.
Abstract In the second part of the review on electrochemical energy storage, the devolvement of batteries is explored. First, fundamental aspects of battery operation will be given, then, different ...materials and chemistry of rechargeable batteries will be explored, including each component of the cell. In negative electrodes, metallic, intercalation and transformation materials will be addressed. Examples are Li or Na metal batteries, graphite and other carbonaceous materials (such as graphene) for intercalation of metal-ions and transition metal oxides and silicon for transformation. In the positive electrode section, materials for intercalation and transformation will be reviewed. The state-of-the-art on intercalation as lithium cobalt oxide and nickel containing oxides will be approached for intercalation materials, whereas sulfur and metal-air will also be explored for transformation. Alongside, the role of electrolyte will be discussed concerning performance and safety, with examples for the next generation devices. Finally, a general future perspective will address both electrochemical capacitors and batteries.
The aim of this work was to establish a modified pre-diagnostic
polymerase chain reaction (PCR) protocol using a single primer set that
enables successful amplification of a highly conserved ...mammalian
sequence in order to determine overall sample DNA quality for multiple
mammalian species that inhabit areas endemic for leishmaniasis. The
gene encoding interphotoreceptor retinoid-binding protein (IRBP), but
not other conserved genes, was efficiently amplified in DNA samples
from tail skin, ear skin, bone marrow, liver and spleen from all of the
species tested. In tissue samples that were PCR-positive for
Leishmania, we found that DNA from 100%, 55% and 22% of the samples
tested resulted in a positive PCR reaction for the IRBP, beta-actin and
beta-globin genes, respectively. Nucleotide sequencing of an IRBP
amplicon resolved any questions regarding the taxonomical
classification of a rodent, which was previously based simply on the
morphological features of the animal. Therefore, PCR amplification and
analysis of the IRBP amplicon are suitable for pre-diagnostically
assessing DNA quality and identifying mammalian species living in areas
endemic to leishmaniasis and other diseases.
•Forest residue removal decreases almost 40% of Eucalyptus wood productivity.•More than 16years are required for the site to recover after residue removal.•Burning forest residues decreased wood ...productivity in the 2nd rotation.•Less than 40% of aboveground macronutrients is in the stem wood compartment.
Forest residue (i.e., litter layer, slash and bark), when used as biomass for energy production, represents an important strategy for use as a renewable energy source in many countries. However, these residues can also have importance as sources of nutrients for trees and soil conservation. The objectives of the present study were to assess the effects of forest residue management on soil, wood production and nutrient accumulation dynamics during two crop rotations in a Eucalyptus grandis plantation. Thus, we set up an experimental site with different intensities of removal, burning and incorporation of forest residues (first crop rotation of study – R1). The stands of all treatments were harvested after eight years, and the trial was re-established with all forest residues maintained on the soil across all treatments (second crop rotation of study – R2). R2 was conducted for eight more years. The growth and nutritional status, biomass and nutrient accumulation of the trees were assessed. The forest residue burn increased the initial nutrient availability in the soil; however, this availability returned to initial levels in a short period of time. Wood productivity decreased by approximately 40% with the removal of all forest residues in R1. In R2, wood productivity after the removal or burning of forest residues was 6% lower than when all forest residues were maintained on the soil.
To assess the prevalence and clustering patterns of cardiometabolic risk factors among low-income, female adolescents.
Cross-sectional study involving 196 students of public schools (11-19 years ...old). The following risk factors were considered in the analysis: excess weight, central obesity, dyslipidemia, high blood pressure, and high fasting glucose. The ratio between observed and expected prevalence and its confidence interval were used to identify clustering of risk factors that exceeded expected prevalence in the population.
The most prevalent risk factors were dyslipidemia (70.9%), and central obesity (39.8%), followed by excess weight (29.6%), and high blood pressure (12.8%). A total of 42.9% of adolescents had two or more risk factors, and 24% had three or more. Excess weight, central obesity, and dyslipidemia were common risk factors in the clustering patterns that showed higher-than-expected prevalence.
Clustering of risk factors (≥ two factors) among the adolescents showed considerable prevalence, and there was a non-casual coexistence of excess weight, central obesity, and dyslipidemia (mainly low HDL-cholesterol).
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