The glass transition dynamics and conductivity relaxation are studied for a series of non-stoichiometric protic ionic liquids (PILs) based on 2-aminoethyl hydrogen sulfate and triflic acid with varying molar ratios (denoted as AT-55, AT-46, AT-37, AT-28, and AT-19) by broadband dielectric spectroscopy in a wide frequency (10-1-107 Hz) and temperature range (173-353 K). The results indicate that the addition of acid lowers the glass transition temperature, as confirmed by the activation energy fine structure analysis and a crossover in the conductivity relaxation time. Notably, samples with higher acid content deliver markedly increased conductivity.
View Article and Find Full Text PDFBackground: Alzheimer's disease (AD) can be optimally managed from a healthcare point of view if detected at a prodromal stage. Amnestic mild cognitive impairment (MCI) is known as prodromal AD, has attracted extensive attention and research.
Objective: To identify the differences in cognitive function and structural magnetic resonance imaging (MRI) features between men and women with MCI on the basis of A/T/N classification system ("A" means amyloid-β biomarker, "T" means tau biomarker, and "N" means neurodegeneration biomarker as determined by clinical imaging (e.
Highly acidic protic ionic liquids (PILs) are promising materials for potential electrochemical applications due to their high proton conductivity and excellent thermal stability. Still, little is known about the correlation between charge transport and structural dynamics as well as the proton transport mechanism despite the large body of literature on this topic. Here, we have examined the charge transport and structural dynamics by employing broadband dielectric spectroscopy in two highly acidic PILs in their supercooled liquid and glassy states, which included the same anion [TfO]- and different cations, [Tau]+ vs [Ahs]+.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2023
Sulfur(VI)-fluoride exchange (SuFEx) chemistry, an all-encompassing term for substitution events that replace fluoride at an electrophilic sulfur(VI), enables the rapid and flexible assembly of linkages around a S core. Although a myriad of nucleophiles and applications works very well with the SuFEx concept, the electrophile design has remained largely SO -based. Here, we introduce S≡N-based fluorosulfur(VI) reagents to the realm of SuFEx chemistry.
View Article and Find Full Text PDFPentafluorosulfanyl (SF )-containing compounds and corresponding analogs are a highly valuable class of fluorine-containing building blocks owing to their unique properties. The reason for that is the set of peculiar and tremendously beneficial characteristics they can impart on molecules once introduced onto them. Despite this, their application in distinct scientific fields remains modest, given the extremely harsh reaction conditions needed to access such compounds.
View Article and Find Full Text PDFJ Phys Condens Matter
June 2022
The calcium hydrides and lanthanum hydrides under high pressures have been reported to have good superconducting properties with high-. In this work, the structures and superconductivities of Ca-La-H ternary hydrides have been studied by genetic algorithm and density functional theory calculations. Our results show that at the pressure range of 100-300 GPa, the most stable structure of CaLaHhas asymmetry, in which there is a Hhydrogen cage.
View Article and Find Full Text PDFSulfur(vi) Fluoride Exchange (SuFEx) chemistry has emerged as a next-generation click reaction, designed to assemble functional molecules quickly and modularly. Here, we report the generation of trifluoromethanesulfonyl fluoride (CFSOF) gas in a two chamber system, and its use as a new SuFEx handle to efficiently synthesize triflates and triflamides. This broadly tolerated protocol lends itself to peptide modification or to telescoping into coupling reactions.
View Article and Find Full Text PDFDiabetic brains are more vulnerable to ischemia-reperfusion injury. Previous studies have proved that melatonin could protect against cerebral ischemia-reperfusion (CIR) injury in non-diabetic stroke models; however, its roles and the underlying mechanisms against CIR injury in diabetic mice remain unknown. Streptozotocin-induced diabetic mice and high-glucose-cultured HT22 cells were exposed to melatonin, with or without administration of the autophagy inhibitor 3-methyladenine (3-MA) and the specifically silent information regulator 1 (SIRT1) inhibitor EX527, and then subjected to CIR or oxygen-glucose deprivation/reperfusion operation.
View Article and Find Full Text PDFCadmium (Cd) is easily enriched in rice, resulting in an excessive Cd content in the grain, which seriously threatens human health. Manganese (Mn) is an essential element of plants. In a field experiment on Cd-contaminated acid soils, we investigated the effectiveness and mechanism of Mn in minimizing Cd accumulation in rice via foliar spraying using 0.
View Article and Find Full Text PDFBackground And Objectives: Aging and deterioration mark a new phase in many older adults' life, highlighting the importance of creativity and imagination. This article introduces the implementation of an innovative program, Play Intervention for Dementia, at a nursing home in Hong Kong, with emphasis on its contribution to the conceptual framework for understanding the selfhood of older adults with dementia.
Research Design And Methods: As a community-based participatory action research project, this study democratized knowledge production by integrating voices of practitioners with diverse backgrounds through video-based methods.
Environ Sci Pollut Res Int
December 2020
In order to unravel the cadmium (Cd) enrichment patterns in rice (Oryza sativa L.) grown under different exogenous exposure pathways, the pot experiment was conducted in a greenhouse. Cd was added to the soil-rice system via mixing soil with Cd-containing solution, irrigating the pots with Cd-containing water and leaf-spraying with Cd solution to simulate soil pollution (SPS), irrigation water pollution (IPS), and atmospheric deposit pollution sources (APS), respectively.
View Article and Find Full Text PDFTwo periodic two-dimensional lattices overlap with each other with a twisted angle can result in moiré patterns (MPs). In this in silico study, we show that by using amphiphilic Janus nanoparticles (JNPs) as a building block, the MPs of JNPs emerge spontaneously via direct self-assembly in dilute solution additional complicated operation. The formation of MPs is attributed to the hydrophobicity of the nanoparticles (and the so-induced "force strings" at the membrane rim) together with suitable grafted hydrophilic and hydrophobic chain lengths.
View Article and Find Full Text PDFThe dynamic process of synthesizing Janus nanoparticles (JNPs) at a water/oil two-phase interface using a grafting-from reaction is investigated via dissipative particle dynamics simulations. We find that the interfacial tension, the initial monomer concentration, and the reaction probability can greatly influence the microscopic characteristics of JNP structure. It is difficult to synthesize a symmetric JNP with an equal volume ratio between hydrophilic and hydrophobic parts by grafting-from methods unless the physical chemical conditions in the two phases are strictly symmetric, and there is always a disordered domain on the JNP at a two immiscible solvents interface.
View Article and Find Full Text PDF3-Fluorooxindoles and the dibenzo[,][1,4]oxazepane scaffolds are important pharmacophores that have important application in medicinal chemistry. An organocatalyzed asymmetric Mannich reaction of 3-fluorooxindoles with dibenzo[,][1,4]oxazepines affording various seven-member cyclic amines containing chiral tetrasubstituted C-F stereocenters was developed. These reactions which were catalyzed by a bifunctional alkaloid-derived thiourea catalyst afforded a wide range of substrates in moderate to high yields with excellent diastereo- and enantioselectivities (up to 88% yield, >20:1 dr and >99% ee).
View Article and Find Full Text PDFAn enantioselective Mannich reaction between 3-fluorooxindoles and pyrazolinone ketimines has been developed for the construction of amino-pyrazolone-oxindoles containing stereogenic C-F units. Based on this new protocol that allows for the generation of two adjacent tetrasubstituted stereocenters, a variety of structurally diverse fluorinated amino-pyrazolone-oxindoles were obtained in good to excellent yields with excellent diastereoselectivities and enantioselectivities (up to 98% yield, >20 : 1 dr and >99% ee). What's more, good yield and high stereoselectivities were obtained in the gram-scale reaction.
View Article and Find Full Text PDFA field experiment was carried out in a six-year old 'Fuji3'/M26/Malus hupehensis Rehd. apple with N and C labeled tracers, to understand C assimilation capability and the characteristics of translocation and distribution of C-photosynthate and N to fruit under different nitrogen application levels (urea 0%, 0.6%, 1.
View Article and Find Full Text PDFWe built a tethered nanoparticle (TNP) model that is composed of a nanoparticle with a hydrophobic tethered polymer chain. The shape of the nanoparticle can be tuned from a pure rigid cube to a soft sphere, mimicking the increase of grafting density on the nanocube surfaces. With this model, we study the self-assembly of TNPs in dilute solution using a dissipative particle dynamics simulation technique, and especially focus on the influence of particle shape, tethered chain length, and grafting density on the self-assembly structures.
View Article and Find Full Text PDFMacrolides have been reported to modify the host immune and inflammatory responses both in vivo and in vitro. We examined the in vitro effect of the macrolides tilmicosin and tylosin, which are only used in the veterinary clinic, on the production of nitric oxide (NO), prostaglandin E(2) (PGE(2)) and cytokines by lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and mouse peripheral blood mononuclear cells (PBMCs).
View Article and Find Full Text PDF