Haaningkoch7606

Chronoamperometric studies confirmed the excellent stability of the catalyst. The present work demonstrates that the electrocatalytic activity of earth-abundant amorphous metal oxides can be strongly enhanced by integrating metallic nanoparticles (NPs) and optimizing nanostructures.We report a systematic study on the variation of the physical properties of Ni3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) in the context of their influence on the capacitive behavior of this material in supercapacitor electrodes prepared using the neat MOF. We find that, for this representative material, the sample morphology has a greater impact on the measured electrode performance than differences in bulk electrical conductivity.In our study, a simple method was employed to prepare ultra-micropore-dominated carbon materials with controllable pore size. A mass of heteroatoms was introduced by surface functional group grafting, resulting in enhanced electrochemical performance the maximum specific capacity of 327.5 F g-1 was obtained at 0.5 A g-1 in 6 M KOH, while that of un-grafted original ultra-microporous carbon was only 188 F g-1, with long-term cycle stability (90.5% of the initial after 10 000 cycles), and excellent rate performance (over 82% at the current density from 0.5 A g-1 to 10 A g-1). The mechanism behind the improved performance was due to the presence of the introduced functional groups that improved the surface wettability of the material and provided additional redox active sites. Their synergistic effects promoted the enhanced electrochemical performance of the ultra-microporous carbon. This study provides a basis for the study of the energy storage mechanism of ultra-microporous carbon and the grafted modification of carbon materials with heteroatom-containing functional groups.Four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters on soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. click here PFAA concentrations were measured in soil, soil pore water, and different plant parts at harvest. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length, by a factor of 10 for each additional fluorinated carbon (nCF) for pea. Three processes were responsible for most of the variability. The first was sorption to soil; calculating whole plant concentration factors on the basis of concentration in pore water instead of soil reduced the variability from five orders of magnitude to two. Second, the journey of the PFAAs with the transpiration stream to the leaves was hindered by retention in the roots driven by sorption; root retention factors increased by a factor 1.7 for each nCF. Third, transfer of PFAAs from the leaves to the fruit via the phloem flow was also hindered - presumably by sorption; fruit/leaf concentration factors decreased by a factor 2.5 for each nCF. A simple mathematical model based on the above principles described the measured concentrations in roots, leaves, fruits and radish bulbs within a factor 4 in most cases. This indicates that the great diversity in PFAA transfer from soil to crops can be largely described with simple concepts for four markedly different species.This review reports a survey on the progress in developing highly efficient platinum nanocatalysts for the hydrolytic dehydrogenation of ammonia borane (AB). After a short prelude emphasizing the importance of increasing the atom efficiency of high cost, precious platinum nanoparticles (NPs) which are known to be one of the highest activity catalysts for hydrogen generation from the hydrolysis of AB, this article reviews all the available reports on the use of platinum-based catalysts for this hydrolysis reaction covering (i) early tested platinum catalysts, (ii) platinum(0) NPs supported on oxides, (iii) platinum(0) NPs supported on carbonaceous materials, (iv) supported platinum single-atom catalysts, (v) bimetallic- and (vi) multimetallic-platinum NP nanocatalysts, and (vii) magnetically separable platinum-based catalysts. All the reported results are tabulated along with the important parameters used in the platinum-catalyzed hydrolysis of AB. In the section "Concluding remarks and a look towards the future" a discussion is devoted to the approaches for making high cost, precious platinum catalysts as efficient as possible, ultimately lowering the cost, including the suggestions for the future research in this field.In this work, we explore the ability of newly synthesized threonine-derived surfactants to form robust, versatile and cytocompatible catanionic vesicles when mixed with gemini surfactants, as potential effective nanocarriers for biomolecules. The threonine surfactants consist of single-tailed amphiphiles with carboxylate headgroups and varying alkyl tail length, CnThr, where n is the (even) number of tail C atoms, varying from 8 to 16. After an initial characterization of the micellization behavior of the neat CnThr surfactants (at pH = 7 and 12), the dodecyl derivative, C12Thr, was selected as the optimal surfactant to investigate regions of formation of spontaneous catanionic vesicles. Phase behavior studies and microstructural characterization of mixtures involving both conventional bis-quat n-s-n gemini (where n and s are the tail and spacer number of C atoms) and biocompatible serine-derived gemini surfactants were carried out. Light and electron microscopy, dynamic light scattering and zeta potential measurements show spontaneous vesicles indeed form and exhibit versatile features in terms of average size, morphology, polydispersity, surface charge and pH. The toxicological profile of the neat surfactants and C12Thr/gemini vesicles based on MTT assays with a L929 cell line was also evaluated, showing good levels of in vitro cytocompatibility. Overall, the assortment of developed catanionic vesicles offers very attractive physicochemical and biological features to be explored for delivery purposes.It remains a great challenge to control the morphology and size of self-assembled homopolypeptide aggregates. In this work, rod-like micelles including spindles and cylinders were prepared by a solution self-assembly of poly(γ-benzyl-l-glutamate) (PBLG) homopolypeptides with different degrees of polymerization, in which their size was controlled precisely by tuning the ratio of water/methanol in selective cosolvents. The length of the rod-like micelles increased with an increasing amount of methanol in the selective cosolvents, which was confirmed using the combination of SEM, TEM and AFM. The self-assembly mechanism of PBLG in selective cosolvents was investigated by using complementary Fourier transform infrared (FT-IR), circular dichroism (CD) and low-field NMR analyses. It was found that the shrinkage and swelling of PBLG chains play important roles in the self-assembly process. The obtained results may provide a guideline for the study of regulating the assembled aggregate sizes.The impact of two nonionic surfactants, namely Span 20 and Span 85, on the electrorheological response and colloidal stability of urea-coated barium titanyl oxalate (BTRU)/silicone oil suspensions is investigated. We quantitatively analyze the surfactant effect on modified ER performance through the measurements of yield stress and current density, as well as the tuned suspension stability through calculation of the Turbiscan stability index (TSI) and naked-eye observations of sedimentation phenomena. The surfactant effect on particle-oil interactions and agglomeration effects is examined by measuring the permeability of silicone oil when mixed with the Span surfactant and the cluster size of particles in dispersing medium, respectively. Our results indicate that with the presence of a Span surfactant, the yield stress of the suspension exhibits a local maximum at certain Span concentrations. We hypothesize that below the optimal Span concentration, the ER properties are enhanced by the increase of the electrostatic interaction between particles. Above the limiting concentration, the ER activity is weakened by the formation of a double-layer surfactant structure that generates a steric hindrance effect. We discover that the addition of the Span surfactant favors the improvement of the particle agglomeration phenomenon, thereby promoting colloidal stability of the suspension. Consequently, in the consideration of both ER properties and suspension stability, an optimal ER fluid with the addition of 0.4 wt% Span 85 is acquired with remarkable integrated ER properties.To improve in vivo osseointegration of pure titanium implant, Sr-Ga clavate double hydroxide (CDH) coating was grown in situ on a titanium (Ti) substrate with simple hydrothermal and calcination treatments at 500 °C. The obtained coating on the Ti substrate (Ti-CDH and Ti-CDH500) was researched by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Ti-CDH exhibited a sustained release profile of metal ions and maintained a slightly alkaline environment. The CDH coating was beneficial for osteogenic differentiation of mesenchymal stem cells (MSCs), which were reflected by the results of cellular assays, including alkaline phosphatase activity (ALP), cell mineralization capability (ARS), and osteogenesis-related gene expression. Besides, Ti-CDH could effectively improve the autophagic levels in MSCs, which further promoted osteogenic differentiation of MSCs. Hence, the Ti surface with Sr-Ga CDH modification supplied a simple and effective strategy to design biomaterials for bone generation.The Rouse model with internal friction (RIF), a widely used theoretical framework to interpret the effects of internal friction on conformational transitions in biomolecules, is shown to be an approximate treatment that is based on preaveraging internal friction. By comparison with Brownian dynamics simulations of an exact coarse-grained model that incorporates fluctuations in internal friction, the accuracy of the preaveraged model predictions is examined both at and away from equilibrium. While the two models predict intrachain autocorrelations that approach each other for long enough chain segments, they differ in their predictions for shorter segments. Furthermore, the two models differ qualitatively in their predictions for the chain extension and viscosity in shear flow, which is taken to represent a prototypical out-of-equilibrium condition.We report an ion concentration polarization (CP) system that exceeds ohmic scaling, a barrier that has stood for more than four decades, by more than one order of magnitude. CP is used in many important applications, including the enrichment of trace analytes in microfluidic systems and water purification by electrodialysis. The mechanisms that control the current through these systems have been largely discovered, but the reduced currents and loss of efficiency imparted by the high resistance of the CP ion depleted zone have not been overcome. To obtain high currents, an ion permselective element with a microscale cross-section is interfaced with a macroscale reservoir. Confocal fluorescence microscopy and microparticle tracking velocimetry (μ-PTV) are used to characterize the depleted zone that emanates vertically from the CP inducing nanoporous gel into the macroscale reservoir. The shape and growth of the depleted zone and velocity in the surrounding bulk solution are consistent with natural convection being the driver of the depleted zone morphology and eliminating the high resistance created by the depleted zone in 1D and 2D systems.