Floodmckay3180

Transmission of chemical signals across lipid bilayer membranes can be achieved using membrane-anchored molecules, where molecular motion across the bilayer is controlled by switching the polarity of two different head groups. An external redox signal delivered by ascorbic acid was used to trigger membrane translocation in a synthetic transduction system.A novel enhanced enzyme-linked aptamer assay (ELAA) for the detection of zearalenone (ZEN) was developed based on gold nanoparticles (AuNPs) modified with an aptamer and horseradish peroxidase (HRP). In this assay, the aptamer was used as a recognition probe to competitively bind with coated ZEN-BSA on a microplate and ZEN in samples. AuNPs with high surface areas were used as a carrier to immobilize more amounts of HRP labelled aptamer probe, which can amplify the colorimetric signal by enhancing catalysis of the HRP enzyme compared with the traditional enzyme-linked method. Under the optimal conditions, the enhanced ELAA presented a good linearity in the range of 0.1-160 ng mL-1 and the limit of detection was 0.08 ng mL-1 for ZEN detection. In addition, the enhanced ELAA had no cross reactivity with other mycotoxins and showed good recoveries in spiked corn oil samples. These results indicated that the AuNP enhanced ELAA provided a new approach with simplicity, and high sensitivity and specificity for the detection of ZEN in foodstuff.Acrylonitrile (AN) and ammonia (NH3) are two important nitrogen-containing interstellar molecules in outer space, especially on Titan. Herein, we measured infrared (IR) spectra of neutral and cationic AN-NH3 complexes by VUV single-photon ionization combined with time-of-flight mass spectrometry. On combining IR spectra with the theoretical calculations, we found that the molecules prefer to form a single-ring cyclic H-bonded structure in the neutral AN-NH3 and (AN)2-NH3 clusters. However, after ionization of AN-NH3 and (AN)2-NH3 clusters, a new C-N-covalent bond is confirmed to form directly between AN and NH3, without any energy barrier in the cationic complexes. Moreover, in the ionized (AN)2-NH3 cluster, the covalent C-N bond prefers to form between AN and NH3 rather than the two AN groups. These results provide spectroscopic evidence of AN forming a new molecule with NH3, induced by VUV radiation. The formation of the new C-N bond broadens our knowledge on the evolution of the prebiotic nitrogen-containing molecules in space.α-Alkylation of methyldiarylphosphine oxides with (hetero)arylmethyl alcohols was performed under nickel catalysis. Various arylmethyl and heteroarylmethyl alcohols can be used in this transformation. A series of methyldiarylphosphine oxides were alkylated with 30-90% yields. Functional groups on the aromatic rings of methyldiarylphosphine oxides or arylmethyl alcohols including OMe, NMe2, SMe, CF3, Cl, and F groups can be tolerated. The conditions are also suitable for the α-alkylation reaction of dialkyl methylphosphonates.Coacervates are condensed liquid-like droplets formed by liquid-liquid phase separation of molecules through multiple weak associative interactions. In recent years it has emerged that not only long polymers, but also short peptides are capable of forming simple and complex coacervates. The coacervate droplets they form act as compartments that sequester and concentrate a wide range of solutes, and their spontaneous formation make coacervates attractive protocell models. The main advantage of peptides as building blocks lies in the functional diversity of the amino acid residues, which allows for tailoring of the peptide's phase separation propensity, their selectivity in guest molecule uptake and the physicochemical and catalytic properties of the compartments. The aim of this tutorial review is to illustrate the recent developments in the field of peptide-based coacervates in a systematic way and to deduce the basic requirements for both simple and complex coacervation of peptides. We review a selection of peptide coacervates that illustrates the essentials of phase separation, the limitations, and the properties that make peptide coacervates biomimetic protocells. Finally, we provide some perspectives of this novel research field in the direction of active droplets, moving away from thermodynamic equilibrium.Optically inactive, paramagnetic Ir(iii)(ppy)3 and Ir(iii)(ppy)2(acac) (ppy 2-phenylpyridinate and acac acetylacetonate) showed nearly mirror-symmetric magnetic circularly polarised luminescence (MCPL) spectra in dilute dichloromethane and dimethyl sulfoxide under N-up and S-up geometries in a 1.6-T magnetic field. However, the MCPL signs of Ir(iii)(ppy)3 and Ir(iii)(ppy)2(acac) under the same N-up (or S-up) Faraday geometry were opposite to each other when one ppy was replaced with an acac. This ligand exchange approach provides facile control of the MCPL sign, irrespective of the Faraday geometry.Hydrated acceptor-doped barium zirconate is a well-investigated proton conductor. In the analysis of most experimental studies, an ideal defect model is applied to fit the measured hydration data and obtain corresponding enthalpies and entropies. However, the data show a distinct deviation from ideal behaviour and thus defect interactions cannot be neglected. In the present contribution, the thermodynamics of water uptake into the yttrium-doped bulk material are investigated on the microscopic level with regards to ionic defect interactions. Metropolis Monte Carlo simulations using interaction models from first-principles energy calculations are applied to obtain an estimation of the free energy of interaction. The present results indicate that the ionic defect interactions are the primary reason for the non-ideality observed in experiments with varying yttrium fraction, proton fraction, and temperature. The activity coefficient quotients for the mass action law are obtained, which connect the ideal and real model and are of relevance to data evaluation and theoretical calculations.The coordination connection of organic linkers to the metal clusters leads to the formation of metal-organic frameworks (MOFs), where the metal clusters and ligands are spatially entangled in a periodic manner. The immense availability of tuneable ligands of different length and functionalities gives rise to robust molecular porosity ranging from several angstroms to nanometres. Among the large family of MOFs, hafnium (Hf) based MOFs have been demonstrated to be highly promising for practical applications due to their unique and outstanding characteristics such as chemical, thermal, and mechanical stability, and acidic nature. Since the report of UiO-66(Hf) and DUT-51(Hf) in 2012, less than 200 Hf-MOFs (ca. 50 types of structures) have been reported. Besides, tetravalent cerium [Ce(iv)] has been proven to be capable of forming similar topological MOF structures to Zr and Hf since its first discovery in 2015. So far, ca. 40 Ce(iv) MOFs with 60% having UiO-66-type structure have been reported. This review will offer a holistic summary of the chemistry, uniqueness, synthesis, and applications of Hf/Ce(iv)-MOFs with a focus on presenting the development in the Hf/Ce(iv)-clusters, topologies, ligand structures, synthetic strategies, and practical applications of Hf/Ce(iv)-MOFs. In the end, we will present the research outlook for the development of Hf/Ce(iv)-MOFs in the future, including fundamental design of Hf/Ce(iv)-clusters, defect engineering, and various applications including membrane development, diversified types of catalytic reactions, irradiation absorption in nuclear waste treatment, water production and wastewater treatment, etc. We will also present the emerging computational approaches coupled with machine-learning algorithms that can be applied in screening Hf and Ce(iv) based MOF structures and identifying the best-performing MOFs for tailor-made applications in future practice.Perillae Folium is a well-known traditional Chinese medicine, and it possesses anti-inflammatory, anti-oxidant, and hypolipidemic effects. read more The pharmacological properties of Perillae Folium are based on its main functional compositions, such as phenolic acids, flavonoids, and volatile oils. In this study, seven polyphenols, including three phenolic acids and four flavonoid glycosides, were successfully isolated from Perillae Folium by pH-zone-refining counter-current chromatography (pH-ZRCCC) combined with traditional high-speed counter-current chromatography (HSCCC). First, the crude sample was separated by pH-ZRCCC using a biphasic solvent system composed of pet ether-ethyl acetate-acetonitrile-water (1  3  1  5, v/v). The upper phase of the biphasic solvent system added trifluoroacetic acid (10 mM) as the stationary phase, and the lower phase added ammonia water (30 mM) as the mobile phase. In this separation, one compound, rosemary acid (I), with high purity and a mixture were obtained. The mixture was further separated using HSCCC with a ethyl acetate-n-butanol-water (4.8  0.2  5, v/v) solvent system to obtain apigenin-7-O-[β-d-glucuronopyranosyl (1→2)-O-β-d-glucuronopyranoside] (II), luteolin-7-O-β-d-glucuronide (III), 4-hydroxycinnamic acid (IV), scutellarin (V), caffeic acid (VI), and apigenin-7-O-β-d-glucuronide (VII). The purities of the obtained compounds were above 92.7%. The study demonstrated that the combination of pH-ZRCCC and HSCCC is an effective method for the preparation and separation of polyphenols, particularly the complex mixture of phenolic acids and flavonoids from natural products.A microfluidics-based three-dimensional skin-on-chip (SoC) model is developed in this study to enable quantitative studies of transendothelial and transepithelial migration of human T lymphocytes in mimicked skin inflammatory microenvironments and to test new drug candidates. The keys results include 1) CCL20-dependent T cell transmigration is significantly inhibited by an engineered CCL20 locked dimer (CCL20LD), supporting the potential immunotherapeutic use of CCL20LD for treating skin diseases such as psoriasis; 2) transepithelial migration of T cells in response to a CXCL12 gradient mimicking T cell egress from the skin is significantly reduced by a sphingosine-1-phosphate (S1P) background, suggesting the role of S1P for T cell retention in inflamed skin tissues; and 3) T cell transmigration is induced by inflammatory cytokine stimulated epithelial cells in the SoC model. Collectively, the developed SoC model recreates a dynamic multi-cellular micro-environment that enables quantitative studies of T cell transmigration at a single cell level in response to physiological cutaneous inflammatory mediators and potential drugs.The results of He atom scattering experiments on KTa0.48Nb0.52O3(001) surfaces are presented and compared with similar experiments on mixed potassium tantalate/niobate perovskites with lower concentrations of Nb. The results are puzzling, unique and intriguing. Angular distributions of the He scattering intensities (the He surface diffraction pattern) are found to be very similar to those obtained from targets with lower Nb fractions. However, drift spectra (the intensity of the He specular reflection as a function of the He wave vector) are not. Whereas the drift spectra in the 〈10〉 azimuth do resemble those of the 0, 6 and 10% Nb fraction targets, in the 〈11〉 azimuth they are more similar to the strange drift spectra found from the 30% Nb-doped targets. Most intriguing are the surface temperature scans (the He specular intensity as a function of the target surface temperature); for they are quite distinct from those with lower Nb fractions. Finally, the inelastic He scattering experiments provide phonon dispersion results that are similar in most respects to those found for the lower Nb level samples.