In this study, the surface tension and the structure of hydrated reline are investigated by using diverse methods. Initially, the surface tension displays a nonlinear pattern as water content increases, decreasing until reaching 45 wt %, then gradually matching that of pure water. This fluctuation is associated with strong electrostatic correlations present in pure reline, which decrease as more water is added.
View Article and Find Full Text PDFObjectives: Humor is essential to social relationships. Its use and understanding appear to be impaired in people with Autism Spectrum Disorder (ASD). The main objective was to review the existing literature on the detection, understanding and use of humor in persons with ASD.
View Article and Find Full Text PDFAs a new generation of green solvents, deep eutectic solvents (DESs) are considered a promising alternative to current harsh organic solvents and find application in many chemical processing methods such as extraction and synthesis. DESs, normally formed by two or more components via various hydrogen bond interactions, offer high potential as medium for biocatalysis reactions where they can improve efficiency by enhancing substrate solubility and the activity and stability of the enzymes. In the current study, the stabilization of Humicola insolens cutinase (HiC) in natural deep eutectic solvents (NADESs) was assessed.
View Article and Find Full Text PDFMetallic bismuth and Bi-oxyfluoride nanoparticles (NPs) are successfully synthesized by non-reactive and reactive sputtering of a Bi target onto 1-butyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)imide ([BMIM][TFSI]) ionic liquid (IL). Non-reactive sputtering is realized in pure Ar plasma, where isotropic, well crystallized and dispersed Bi NPs of 3-7 nm are obtained. The diameter and the size distribution of these NPs do not significantly vary with the power, gas pressure, and sputtering time; but these sputtering parameters seem to influence the NP concentration.
View Article and Find Full Text PDFTire and road wear particles (TRWP) are polymer-based microparticles that are emitted into the environment during tire usage. Growing efforts are currently being made to quantify these emissions, characterize the leachates and assess their environmental impact. This study aimed to investigate the effect of aging on TRWP composition.
View Article and Find Full Text PDFIn recent years, natural deep eutectic solvents (NADESs) have gained increasing attention as promising nontoxic solvents for biotechnological applications, due to their compatibility with enzymes and ability to enhance their activity. Betaine-based NADESs at a concentration of 25 wt % in a buffered aqueous solution were used as media to inhibit thermal inactivation of POXA1b laccase and its five variants when incubated at 70 and 90 °C. All the tested laccases showed higher residual activity when incubated in NADES solutions, with a further enhancement achieved also for the most thermostable variant.
View Article and Find Full Text PDFInt J Biol Macromol
November 2020
The wide-spread use of laccases in industry is often limited due to the enzyme inactivation over time at conditions which exceeds the operating conditions of the enzymes, which are neutral pH and ambient temperatures (30-40 °C). Natural Deep Eutectic Solvents (NADESs) have attracted considerable attention as reaction media in biocatalysis due to their promising compatibility with enzymes and sustainable derivation. In this contribution we demonstrate the possibility of applying aqueous NADESs as incubation media to alter the activity and inhibit thermal inactivation of laccase T.
View Article and Find Full Text PDFThe liquid-phase exfoliation of graphite is one of the most promising methods to increase production and commercial availability of graphene. Because ionic liquids can be easily obtained with chosen molecular structures and tuneable physicochemical properties, they can be use as media to optimize the exfoliation of graphite. The understanding of the interactions involved between graphite and various chemical functions in the solvent ions will be helpful to find liquids capable of dissociating and stabilizing important quantities of large graphene layers.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2017
Several mixtures of butyl acetate (BA) and an ionic liquid (1-methyl-3-octylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [CCPyrro][NTf], 1-octyl-pyridinium bis(trifluoromethylsulfonyl)imide, [CPyr][NTf], 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide, [CCIm][NTf] or 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide, [CCIm][NTf]) have been characterized by measuring density, viscosity and conductivity, from pure BA to pure ILs at 298.15 K. The ionicity of these mixtures has been determined on the basis of electrical conductivity and NMR spectroscopy.
View Article and Find Full Text PDFThe aim of this work is to understand the details of the interactions of ionic liquids with carbon nanomaterials (graphene and nanotubes) using polyaromatic compounds as model solutes. We have combined the measurements of thermodynamic quantities of solvation with molecular dynamics simulations to provide a microscopic view. The solubility of five polycyclic aromatic hydrocarbons (naphthalene, anthracene, phenanthrene, pyrene and coronene) was determined in seven ionic liquids ([CCim][C(CN)], [CCpyrr][Ntf], [CCim][Ntf], [CCim][C(CN)], [CCim][Ntf], [CCpyrr][N(CN)] and [CCim][N(CN)]) at 298 K.
View Article and Find Full Text PDFTwenty ionic liquids based on tetraalkylammonium cations and carboxylate anions have been synthesized, characterized, and tested for cellulose dissolution. The amount of cellulose dissolved in these ionic liquids depends strongly on the size of the ions: from 0 to 22 wt % cellulose can be dissolved at 90 °C. The best ionic liquids are less viscous and ammonium carboxylate based ionic liquids can dissolve as much as imidazolium-based ones.
View Article and Find Full Text PDFChem Commun (Camb)
March 2015
The heat of dissolution of cellulose in one imidazolium acetate ionic liquid was determined experimentally. The value of -132 ± 8 J g(-1) indicates that the dissolution is exothermal thus confirming energetically favourable cellulose-ionic liquid interactions but indicating that an increase in temperature does not thermodynamically favour the dissolution process.
View Article and Find Full Text PDFBackground: During recent years, fictions featuring a character with Asperger syndrome have been increasingly produced in literature, cinema and TV. Thus, the public has gradually discovered the existence of this specific category of autism spectrum, which is far removed from old popular representations of autistic disorders, often associated with mental retardation.
Objectives: To describe the reactions generated by these characters in order to identify their major functions and also to try to explain their recent increase in fictions.
Poly(vinylpyrrolidone) (PVP)-stabilized Pd nanocubes were synthesized, deposited on a carbon-based support, and subsequently treated with UV-ozone (UVO) in order to eliminate the traces of PVP still present on the surface. Cubes, being a thermodynamically unfavorable shape, are very prone to restructuring to minimize the interfacial free energy and thus allow the assessment of their morphological stability during UVO cleaning. The process of PVP removal was monitored by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and in situ attenuated total reflection infrared spectroscopy (ATR-IR).
View Article and Find Full Text PDFBackground: First described in 1944 by Hans Asperger, Asperger syndrome (AS) is now considered in international diagnostic classifications as one of the pervasive developmental disorders (PDD) or autism spectrum disorders (ASD). The main symptoms of AS are severe impairment in social interaction and communication, and restricted interests, without significant delay in cognitive and language development. Its prevalence is not clearly established but might be around 0.
View Article and Find Full Text PDFIn situ attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy has gained considerable attention as a powerful tool for exploring processes occurring at solid/liquid and solid/liquid/gas interfaces as encountered in heterogeneous catalysis and electrochemistry. Understanding of the molecular interactions occurring at the surface of a catalyst is not only of fundamental interest but constitutes the basis for a rational design of heterogeneous catalytic systems. Infrared spectroscopy has the exceptional advantage to provide information about structure and environment of molecules.
View Article and Find Full Text PDFAttenuated total reflection (ATR) Fourier transform infrared (FT-IR) in situ measurements were performed during the catalytic hydrogenation of acetophenone under high pressure (5.0 MPa). The catalyst used was a suspension of rhodium nanoparticles in an ionic liquid.
View Article and Find Full Text PDFTwo commonly used ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]), as well as binary and ternary mixtures of them with water and/or supercritical CO(2) (scCO(2)) were investigated by means of infrared spectroscopy at high pressure. The experiments were performed using attenuated total reflection (ATR) infrared spectroscopy on dry and wet ILs at 40 degrees C and pressures up to 150 bar of scCO(2). The studies indicate that the content of water does not change significantly the solubility of CO(2) in the ionic liquids tested.
View Article and Find Full Text PDFThe CO(2)-catalyzed acetalization is regarded as a promising alternative to the conventional acid-catalyzed method from a viewpoint of green chemistry (C. A. Eckert et al.
View Article and Find Full Text PDFInfrared (IR) spectroscopy has been successfully applied to study the solubility of supercritical (sc) CO2 in an ionic liquid (IL), the swelling of the IL under scCO2, the diffusion of CO2 in the IL, and the molecular interaction between the IL and scCO2 using a single defined experimental setup. The study has been performed using 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] and scCO2 with a pressure of up to 150 bar at 313 K. The solubility of scCO2 in the IL was calculated via the intensity of the CO2 antisymmetric stretching mode, which was measured using the attenuated total reflection (ATR) method.
View Article and Find Full Text PDFInfrared (IR) spectroscopy is one of the most chemically specific analytical methods that gives information about composition, structure, and interactions in a material. IR spectroscopy has been successfully applied to study the permeation of xenobiotics through the skin. Combining IR spectroscopy with an IR array detector led to the development of Fourier transform infrared (FTIR) spectroscopic imaging, which generates chemical information from different areas of a sample at the microscopic level.
View Article and Find Full Text PDFInfrared (IR) spectroscopy has been successfully applied to study the permeation of substances through human skin in a high-throughput manner. The sample of skin was placed on the measuring surface of an attenuated total reflection (ATR) crystal and was divided into several areas. These areas were separated using a specially designed grid created on the surface of the skin and each area was subjected to a different combination of permeant and enhancer.
View Article and Find Full Text PDFIn the context of trans-dermal drug delivery it is very important to have mechanistic insight into the barrier function of the skin's stratum corneum and the diffusion mechanisms of topically applied drugs. Currently spectroscopic imaging techniques are evolving which enable a spatial examination of various types of samples in a dynamic way. ATR-FTIR imaging opens up the possibility to monitor spatial diffusion profiles across the stratum corneum of a skin sample.
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