692 research outputs found
Using Polymeric Ionic Liquids as an Active Binder in Supercapacitors
Electrodes in batteries and supercapacitors generally contain inert binders to maintain their structural integrity during operation but do not participate in the storage of energy. In this paper, we demonstrate that poly ionic liquids can function as structural binders while simultaneously improving the energy storage capability of supercapacitors. Specifically, we show that when the ionic liquid N-butyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide is used as electrolyte and poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide is employed as electrode binder the permissible operating voltage of the device is enhanced to 4.0 V. This results in a substantially increased overall specific energy (80% greater) and represents a step toward the development of devices with long cycle lives and high energy densities
Four Phosphonium-based Ionic Liquids. Synthesis, Characterization and Electrochemical Performance as Electrolytes for Silicon Anodes
Herein, we describe the synthesis, characterization and electrochemical performance of four phosphonium-based ionic liquids (ILs) as electrolytes, Physicochemical properties such as viscosity, density, ionic conductivity, and thermal stability of ILs and conventional organic solvent ethylene carbonate (EC)/diethyl carbonate (DEC) were experimentally determined at different temperatures. All ILs showed thermal stability greater than 300 degrees C, surpassing the stability of the conventional organic solvent, whose flash points were 145 and 23 degrees C for EC and DEC, respectively. Nevertheless, at room temperature, all ILs are much more viscous than EC/DEC. The composite Si -[P-2224][FSI] (triethyl-n-butylphosphonium bis(fluoromethylsulfonyl)imide) and Si-EC/DEC anodes exhibit initial specific capacities at 0.15 A/g of 2409 and 2631 mAh/g, respectively. This demonstrates that despite the inferior transport properties of ILs, short alkyl-substituted phosphonium ILs like [P-2224][FSI] are potentially competitive for the new generation of electrolytes for LIBs. NMR, DSC, TGA, and galvanostatic discharged/charged were used as characterization techniques.Peer reviewe
Development of magnetoelectric CoFe2O4 /poly(vinylidene fluoride) microspheres
Magnetoelectric microspheres based on piezoelectric poly(vinylidene fluoride) (PVDF) and magnetostrictive CoFe2O4 (CFO), a novel morphology for polymer-based ME materials, have been developed by an electrospray process. The CFO nanoparticle content in the (3-7 mm diameter) microspheres reaches values up to 27 wt%, despite their concentration in the starting solution reaching values up to 70 wt%. Additionally, the inclusion of magnetostrictive nanoparticles into the polymer spheres has no relevant effect on the piezoelectric b-phase content (z60%), crystallinity (40%) and the onset degradation temperature (460-465 C) of the polymer matrix. The multiferroic microspheres show a maximum piezoelectric response |d33| z 30 pC N1, leading to a magnetoelectric response of D|d33| z 5 pC N1 obtained when a 220 mT DC magnetic field was applied. It is also shown that the interface between CFO nanoparticles and PVDF (from 0 to 55%) has a strong influence on the ME response of the microspheres. The simplicity and the scalability of the processing method suggest a large application potential of this novel magnetoelectric geometry in areas such as tissue engineering, sensors and actuators
Heat treatment and wounding as abiotic stresses to enhance the bioactive composition of pineapple by-products
Abiotic stress, like heat treatment and wounding, applied to pineapple by-products induce the accumulation of new compounds and add value. In this work the effect of the individual or combined application of wounding and heat treatment stresses on total phenolic content, antioxidant activity through complementary methods (DPPH, FRAP, and ABTS) and enzymatic activity (bromelain, phenylalanine ammonia lyase (PAL) and polyphenol oxidase) were evaluated. Whole and wounded pineapple shell and core were dipped in a hot water bath at 30 ± 1 °C or 40 ± 1 °C for 10 min and stored under refrigeration conditions (4 ± 1 °C) for 24 h or 48 h. Results allowed that pineapple by-products reacted differently to the tested stresses. For the core, the application of wounding and heat treatment (40 °C) before storage (24 h) induced a synergistic effect on the accumulation of phenols (increased 17%) and antioxidant activity (422%). For the shell samples, the treatment that most increased the content of phenols (14%) and antioxidant activity (3845%) was heat treatment at 30 °C and storage for 48 h. Treatments that positively influenced the content of phenols and antioxidant activity of the samples did not affect the activity of bromelain or PAL. This study showed that proper abiotic stresses could increase the functional value of by-products.The first author acknowledges the financial support from Fundação para a Ciência e
a Tecnologia (FCT), Portugal, through Doctoral fellowship (SFRH/BD/109124/2015). This work
was supported by the national funding of FCT, under the scope of the strategic funding to the
research units LEAF, Linking Landscape, Environment, Agriculture, and Food, School of Agriculture,
University of Lisbon, 1349-017 Lisbon (UIDP/04129/2020), Associate Laboratory LAQV-REQUIMTE,
Department of Chemistry, University of Aveiro, 3810-193 Aveiro (UIDB/50006/2020) and CEB, Centre
of Biological Engineering, Department of Biological Engineering, University of Minho, 4710–057
Braga (UIDP/04469/2020) through national funds and where applicable co-financed by the FEDER,
within the PT2020 Partnership Agreement.info:eu-repo/semantics/publishedVersio
One-year timeline kinetics of cytokine-mediated cellular immunity in dogs vaccinated against visceral leishmaniasis
BACKGROUND: The main control strategy for visceral leishmaniasis in Brazil has been based on the elimination of seropositive dogs, although this is not widely accepted. In this context, the use of a long-lasting protective vaccine against canine visceral leishmaniasis (CVL) has been highly expected. The aim of this work was to determine the timeline kinetics of the cytokine microenvironment derived from circulating leukocytes as supportive immunological biomarkers triggered by Leishmune® vaccine. Cross-sectional kinetic analysis of cellular immunity cytokines was carried out at three times (1, 6 and 12 months) after primovaccination with Leishmune®. In vitro short-term whole blood cultures were stimulated with Leishmania infantum soluble antigen (SLAg). The secreted cytokine signatures and their major sources were determined. RESULTS: At six months after vaccination, Leishmune® induced an increase in IL-8, IFN-γ, IL-17a and TNF-α levels and a decrease in IL-10. Cytokine signature analysis revealed a shift in the microenvironment towards a pro-inflammatory profile mediated by IL-8 and IFN-γ. Both, CD4(+) (↑TNF-α(+) and ↑IFN-γ (+)) and CD8(+) (↑IL-17a and ↓IL-4) T-cells contributed to the acquired immune responses observed after stimulation with SLAg. CONCLUSIONS: The changes observed in the cytokine profile suggested that Leishmune® was able to induce an effective response at six months after primovaccination. After one year, it returned to baseline suggesting the need of additional boosting
Seleção de genótipos de mandioca (Manihot esculenta Crantz) tolerantes à seca.
O objetivo deste estudo foi avaliar a produtividade de raízes de genótipos de mandioca (Manihot esculenta Crantz) para a seleção de materiais tolerantes à seca com a finalidade da disponibilização para programas de melhoramento genético
Clinical and genetic analysis of 29 Brazilian patients with Huntington’s disease-like phenotype
Huntington’s disease (HD) is a neurodegenerative disorder characterized by chorea,
behavioral disturbances and dementia, caused by a pathological expansion of the CAG
trinucleotide in the HTT gene. Several patients have been recognized with the typical HD
phenotype without the expected mutation. The objective of this study was to assess the
occurrence of diseases such as Huntington’s disease-like 2 (HDL2), spinocerebellar ataxia
(SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and choreaacanthocytosis
(ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group
analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not
reached in 79.3% of the patients. HDL2 was the main cause of the HD-like phenotype in
the group analyzed, and is attributable to the African ancestry of this population. However,
the etiology of the disease remains undetermined in the majority of the HD negative
patients with HD-like phenotype.
Key words: Huntington’s disease, Huntington’s disease-like, chorea-acanthocytosis,
Huntington’s disease-like 2
Sustainable practices in logistics systems: An overview of companies in Brazil
© 2019 by the authors. The main purpose of this article is to present an overview of the applications of sustainable practices in logistic operations performed by Brazilian companies. To reach this objective, the following steps were carried out: (1) a review of the literature on logistics systems and sustainability in logistics activities; (2) the collection of sustainability reports published by companies that perform logistics operations, which are recognized in Brazil; (3) a content analysis of the reports collected and (4) a discussion of the results, cross-checked with the literature and the extrapolation of conclusions. It was possible to identify 22 sustainable practices, and these practices were grouped into five macro areas. The authors of this paper believe that the findings presented here can be useful for professionals and researchers in the implementation of sustainability practices in logistics systems
Genomic signatures of introgression between commercial and native bumblebees, <i>Bombus terrestris</i>, in western Iberian Peninsula:implications for conservation and trade regulation
Original ArticleHuman‐mediated introductions of species may have profound impacts on native ecosystems.
One potential impact with largely unforeseen consequences is the potential
admixture of introduced with autochthonous species through hybridization.
Throughout the world, bumblebees have been deliberately introduced for crop pollination
with known negative impacts on native pollinators. Given the likely allochthonous
origin of commercial bumblebees used in Portugal (subspecies Bombus
terrestris terrestris and B. t. dalmatinus), our aim was to assess their putative introgression
with the native Iberian subspecies B. terrestris lusitanicus. We analysed one mitochondrial
gene, cytochrome c oxidase subunit I (COX1) and genomic data involving
thousands of genome‐wide restriction‐site‐associated DNA markers (RAD‐seq). In
the mitochondrial COX1 analyses, we detected one relatively common haplotype in
commercial bumblebees, also present in wild samples collected nearby the greenhouses
where the commercial hives are used. In the RAD‐seq analysis, we found a
clear genetic differentiation between native and commercial lineages. Furthermore,
we detected candidate hybrids in the wild, as well as putatively escaped commercial
bumblebees, some of which being potentially fertile males. Although we cannot assess
directly the fitness effects of introgressed alleles, there is a risk of maladaptive
allele introgression to the local bumblebee subspecies, which can negatively impact
autochthon populations. One immediate recommendation to farmers is for the
proper disposal of hive boxes, after their use in greenhouses, so as to minimize the
risk of escapees contaminating native populations. On the other hand, the feasibility
of using local subspecies B. t. lusitanicus, preferably with local production, should be
evaluatedinfo:eu-repo/semantics/publishedVersio
Ionic liquids containing tricyanomethanide anions: physicochemical characterisation and performance as electrochemical double-layer capacitor electrolytes
We investigated the use of fluorine free ionic liquids (ILs) containing the tricyanomethanide anion ([C(CN)3]) as an electrolyte in electrochemical double-layer capacitors (EDLCs). Three cations were used; 1-butyl-3-methylimidazolium ([Im1,4]), N-butyl-N-methylpyrrolidinium ([Pyr1,4]) and N-butyl-N-methylpiperidinium ([Pip1,4]). Their physicochemical properties are discussed alongside with their performance as electrolytes. We found that the cyano-based ILs present higher ionic conductivity (9.4, 8.7 and 4.2 mS cm−1 at 25 °C for [Im1,4], [Pyr1,4] and [Pip1,4], respectively) than the widely studied IL containing the bis(trifluoromethylsulfonyl)imide anion, namely [Pyr1,4][Tf2N] (2.7 mS cm−1 at 25 °C). Of the three ILs investigated, [Pip1,4][C(CN)3] presents the widest electrochemical stability window, 3.0 V, while [Pyr1,4][C(CN)3] is stable up to 2.9 V and its [Tf2N] analogue can operate at 3.5 V. Despite operating at a lower voltage, [Pyr1,4][C(CN)3] EDLC is capable of delivering up to 4.5 W h kg−1 when operating at high specific power of 7.2 kW kg−1, while its [Pyr1,4][Tf2N] counterpart only delivered 3.0 W h kg−1 when operated at similar power
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