Insights on the Behavior of Imidazolium Ionic Liquids as Electrolytes in Carbon-Based Supercapacitors: An Applied Electrochemical Approach

This study aims to increase the knowledge on the interactions that occur at the electrode/electrolyte interface in carbon-based electric double-layer capacitors (EDLCs) when solvent-free ionic liquids are used as electrolytes. Many previous studies found in the literature are conducted using theoretical approaches, and they are unable to model all the variables and the complexity of an actual device with a complex carbon surface and an ionic liquid (IL). Here, the compatibility between imidazolium ionic liquids and different carbon materials-an activated carbon (AC), a mesoporous carbon (MES), multiwalled carbon nanotubes (MWCNTs), and reduced graphene oxide (RGO)-is empirically investigated applying synchronous chronopotentiometric tests to various symmetrical EDLCs. The study of the simultaneous evolution of the cell and electrode potentials of the various carbon/ILs cells, monitoring the evolution of specific capacitances and electrical resistances for each independent electrode, allows inferring about the ion-electrode compatibility, the limiting factors for charge accumulation, and its impacts on the performance of the global cell. The results indicate that the sp2 structures of MWCNTs and RGO favor interactions with the EMI+ cation on the negative electrode. In the positive electrodes, MES and AC favor interactions with the BF4- and TFSI- anions, respectively, yielding a higher specific capacitance and lower resistance.The authors thank the Conselho Nacional de Desenvolvimento Cienti ico e Tecnoló gico (CNPq)−Brazil for the financial support (PVE 2014, process number 400714/2014- 0), the Spanish Government and European Union (AEI/ FEDER, EU; project MAT2016-77114-R), N.Q.’s predoctoral contract (BES2017-082038), and Principado de Asturias (FEDER: IDI/2018/000121). The work was partially supported by the Brazilian Institute of Science and Technology (INCT) in Carbon Nanomaterials. P.F.R.O. acknowledges the Fundaca̧ o de Amparo a ̃ ̀Pesquisa do Estado de Minas Gerais (FAPEMIG)−Brazil (DOF no. 2720262/2018). P.F.R.O. and G. A.d.S. also acknowledge the scholarships received from CNPq. R.L.L. is a recipient of a fellowship from CNPq (grant number 313304/2017-3). P.F.R.O, G.G.S., and R.L.L. are members of the Rede Mineira de Quimica (RQ-MG) ́ −Brazil

Qualidade de mudas de eucalipto produzidas sob diferentes lâminas de irrigação e dois tipos de substrato Quality of eucalyptus seedlings under different depths of irrigation and two substrastes

Este trabalho teve por objetivo avaliar lâminas de irrigação na produção de mudas de Eucalyptus grandis, produzidas em dois substratos comerciais à base de cascas de árvores (CPV e CATV). O experimento foi conduzido na Camará - Mudas Florestais, em Ibaté, SP, na estação inverno/primavera/2003, constituindo-se de um delineamento de blocos ao acaso com quatro repetições, sendo cinco lâminas de irrigação diárias (6, 8, 10, 12 e 14 mm), aplicadas através de uma barra de irrigação em diferentes horários (10, 13 e 16 h). Aos 108 dias após a aplicação foram realizadas avaliações da altura de parte aérea, diâmetro de colo, relação altura da parte aérea/diâmetro de colo, número de pares de folhas, matéria seca da parte aérea e das raízes e área foliar. Com relação às características morfológicas, verificou-se a influência das lâminas em todas as variáveis. Dessa maneira, concluiu-se que as lâminas de irrigação de 12 e de 14 mm dia-1 foram as que mais contribuíram para o desenvolvimento das mudas, com qualidade ótima aos 108 dias após a semeadura.<br>The objective of this work was to evaluate irrigation depths in the production of Eucalyptus grandis seedlings, produced in two commercial substrates containing tree bark (CPV and CATV). The experiments took place in Camará- Mudas Florestais, in Ibaté - São Paulo, from winter to spring/2003, consisting of a randomized blocks design with four replicates, with 5 daily watering (6, 8, 10, 12 and 14 mm), applied several times during the day (at 10 am, 13 pm and 16 pm). At 108 days after sowing, the following parameters were assessed: height of aerial part, neck diameter, relation height of aerial part / neck diameter, number of leaf pairs, dry matter of the aerial part and roots, and leaf area. Depths of 6 and 8 mm per day reduced drastically seedling growth. The irrigation depths also influenced all the parameters of morphological characteristics. It was concluded that the water depths as high as 12 and 14 mm day-1 helped the development of the seedlings, with excellent quality at 108 days after sowing

Heat and exercise acclimation increases intracellular levels of Hsp72 and inhibits exercise-induced increase in intracellular and plasma Hsp72 in humans

In order to verify the effects of heat and exercise acclimation (HA) on resting and exercise-induced expression of plasma and leukocyte heat shock protein 72 (Hsp72) in humans, nine healthy young male volunteers (25.0 ± 0.7 years; 80.5 ± 2.0 kg; 180 ± 2 cm, mean ± SE) exercised for 60 min in a hot, dry environment (40 ± 0°C and 45 ± 0% relative humidity) for 11 days. The protocol consisted of running on a treadmill using a controlled hyperthermia technique in which the work rate was adjusted to elevate the rectal temperature by 1°C in 30 min and maintain it elevated for another 30 min. Before and after the HA, the volunteers performed a heat stress test (HST) at 50% of their individual maximal power output for 90 min in the same environment. Blood was drawn before (REST), immediately after (POST) and 1 h after (1 h POST) HST, and plasma and leukocytes were separated and stored. Subjects showed expected adaptations to HA: reduced exercise rectal and mean skin temperatures and heart rate, and augmented sweat rate and exercise tolerance. In HST1, plasma Hsp72 increased from REST to POST and then returned to resting values 1 h POST (REST: 1.11 ± 0.07, POST: 1.48 ± 0.10, 1 h POST: 1.22 ± 0.11 ng mL−1; p < 0.05). In HST2, there was no change in plasma Hsp72 (REST: 0.94 ± 0.08, POST: 1.20 ± 0.15, 1 h POST: 1.17 ± 0.16 ng mL−1; p > 0.05). HA increased resting levels of intracellular Hsp72 (HST1: 1 ± 0.02 and HST2: 4.2 ± 1.2 density units, p < 0.05). Exercise-induced increased intracellular Hsp72 expression was observed on HST1 (HST1: REST, 1 ± 0.02 vs. POST, 2.9 ± 0.9 density units, mean ± SE, p < 0.05) but was inhibited on HST2 (HST2: REST, 4.2 ± 1.2 vs. POST, 4.4 ± 1.1 density units, p > 0.05). Regression analysis showed that the lower the pre-exercise expression of intracellular Hsp72, the higher the exercise-induced increase (R = −0.85, p < 0.05). In conclusion, HA increased resting leukocyte Hsp72 levels and inhibited exercise-induced expression. This intracellular adaptation probably induces thermotolerance. In addition, the non-increase in plasma Hsp72 after HA may be related to lower stress at the cellular level in the acclimated individuals