Deanhurst6198

The heavy metal pollution induced by agricultural land use change has attracted great attention. In this study, the divergent response of the bioavailability of heavy metals in rhizosphere soil to different agricultural land uses was analyzed using sequential extraction, and possible influence paths were constructed. The results show that land use change can affect the heavy metal bioavailability by influencing the soil organic matter and redox potential (Eh). The average concentrations of N, P, K, Ca, Mg, S, and Fe in the soil showed no significant differences. However, the conversion direction and extent of chemical speciation of heavy metals were different across land use changes from paddy fields to various drylands. After conversion from paddy to wheat field, the bioavailability of heavy metals decreased due to an increase in permanganate oxidizable carbon (KMnO4-C) and a decrease in Eh. The transformation from paddy to celery soil is accompanied by a change in the soil's KMnO4-C content, increasing the proportion of the bioavailable states of heavy metals. However, the response of bioavailability to changes in the soil KMnO4-C varied among heavy metals. In contrast, when land use changed to grapevine culture, the bioavailability of heavy metals increased due to a change in the KMnO4-C content. Moreover, the dissolved organic carbon (DOC) content increased, which positively affected the Eh and, in turn, increased the bioavailability of heavy metals. This research is of great significance for understanding the impact of land use change on the heavy metal migration and activity in the rhizosphere microenvironment of soil.α,β-Unsaturated acyl ammonium species are versatile intermediates that have been applied in a variety of transformations including Michael additions, domino reactions and cycloadditions. Many of these transformations are promoted by chiral Lewis base catalysts, enabling the rapid generation of molecular complexity with high stereochemical control. This review highlights recent developments in the generation and application of α,β-unsaturated acyl ammonium intermediates reported since a previous review of this area in 2016. Particular emphasis will be placed on reports providing mechanistic insight into catalytic transformations and observed selectivities. A perspective on current challenges and potential future developments in the field of α,β-unsaturated acyl ammonium catalysis is also provided.The effect of charges and hydrogen bonding on viscosity in solutions containing polyelectrolyte-grafted nanoparticles (PENP) has been investigated using molecular dynamics (MD) simulations. The electrostatic interaction between the charged monomers on the grafted chains, which increases with the degree of ionization, causes the grafted polymers to stretch and increases the hydrodynamic size of the nanoparticles. The viscosity of the solution is partially governed by the balance between the entanglement of grafted chains and the electrostatic repulsion. Moreover, the charge-assisted hydrogen bonds between the monomers of different particles further enhance the viscosity of the solution. For shorter grafted chains, a majority of hydrogen bonds are formed within the same particle and thus show no significant enhancement in viscosity. The addition of polymer chains with hydrogen bonding sites has been shown to bridge multiple nanoparticles, creating a network structure, that increases viscosity. The chain stiffness has been shown to have a direct correlation with bridging and thus the viscosity of the solution.We report the colloidal synthesis of quaternary kesterite CZTS-CZTSe heterostructures via anion exchange reactions on a kesterite CZTS template. The crystal phase selectivity during the synthesis (kesterite vs. wurtzite) is due to the initial nucleation of cubic Cu9S5 seeds, followed by incorporation of Zn and Sn. Upon injection of Se-precursor, which triggered simultaneous anion exchange and overgrowth of the pristine CZTS template, sandwich CZTS-CZTSe (core-tip) nanoheterostructures were obtained. X-ray photoelectron spectroscopy (XPS) and optical band gap measurement results suggest a change of intrinsic electronic structure of CZTS by Se-treatment. Our study not only provides insight into mechanisms of formation of kesterite CZTS nanocrystals (NCs) and subsequent anion exchange reactions, but also opens doors to access novel CZTSSe nanostructures for potential applications.The electrocatalytic hydrogen evolution reaction (HER) for H2 production is essential for future renewable and clean energy technology. Screening energy-saving, low-cost, and highly active catalysts efficiently, however, is still a grand challenge due to the sluggish kinetics of the oxygen evolution reaction (OER) in electrolyzing water. Herein, we present a single atomic Mn site anchored on a boron nitrogen co-doped carbon nanotube array (Mn-SA/BNC), which is perfectly combined with the hydrazine electrooxidation reaction (HzOR) boosted water electrolysis concept. The obtained catalyst achieves 51 mV overpotential at the current density of -10 mA cm-2 for the cathodic HER and 132 mV versus the reversible hydrogen electrode for HzOR, respectively. Besides, in a two-electrode overall hydrazine splitting (OHzS) system, the Mn-SA/BNC catalyst only needs a cell voltage of only 0.41 V to output 10 mA cm-1, with strong durability and nearly 100% faradaic efficiency for H2 production. This work highlights a low-cost and high-efficiency energy-saving H2 production pathway.The dissolution of polysulfides in an electrolyte is a thermodynamically favorable process, which in theory means that the shuttle effect in lithium-sulfur batteries (LSBs) cannot be completely suppressed. So, it is very important to modify the separator to prevent the migration of polysulfides to the lithium anode. The traditional coating modification process of the separator is cumbersome and uses a solvent that is harmful to the environment, and too many inactive components affect the overall energy density of the battery. It is thus imperative to find a simple and environmentally friendly modification process of the separator. Zamaporvint nmr In this study, a fast chemical film-forming method is proposed to modify the separator of a lithium-sulfur battery using tannic acid (TA) and cobalt ions (Co2+). This method requires only simple steps and environmentally friendly raw materials to obtain a thin coating (only 5.83 nm) that can effectively inhibit the shuttle effect. The lithium-sulfur battery with the TA-Co separator shows superior long cycle performance. After 500 cycles at 0.5 C, the capacity decay rate of each cycle is only 0.065%. link2 On the other hand, the TA-Co separator can inhibit the growth of lithium dendrites and help to build a stable lithium anode, which can exhibit minimal polarization (56 mV) in a lithium-lithium symmetrical battery at the current density of 2 mA cm-2. The rapid and simple modification method proposed in this study has a certain reference value for the future large-scale application of lithium sulfur batteries.Mitochondria are the main sites for the production of hypochlorite (OCl-). The protein adenine nucleotide translocase (ANT) is located in the inner mitochondria membrane, which is mainly participated in the transportation of ions and metabolites. At the cellular organelle level, overexpression of ANT is associated with enhanced production of OCl-, however, abnormal levels of OCl- cause redox imbalance and loss of function of mitochondria. Herein, a novel mitochondria-targeted ratiometric fluorescent probe Mi-OCl-RP has been developed. Molecular docking calculation suggested a potential molecular target for the probe in the ANT, and the high binding energy (-8.58 kcal mol-1) may explain the high mitochondria selectivity of Mi-OCl-RP. The unique probe exhibits excellent spectral properties including ratiometric fluorescence response signals to OCl- (within 7 s), high selectivity and sensitivity, and a large Stokes shift (278 nm). In addition, the colocalization coefficient confirms that Mi-OCl-RP can effectively target mitochondria. Furthermore, Mi-OCl-RP has low toxicity and good permeability, and was successfully employed in ratiometric imaging of OCl-in vivo, affording a robust molecular tool for investigating the biological functions of OCl- in living systems.Incorporation of nanoparticles has been considered as an efficient method for enhancing the adsorption performance of metal-organic frameworks (MOFs). Alkali metal compounds possess outstanding affinity to acidic CO2. In this study, a robust self-conversion strategy is reported for improving the carbon capture performance of MOFs, through directly transforming partial metal centers to basic carbonate (BC) nanoparticles. Based on the hydrolysis of coordination bonds induced by water impurity in solvents and the decarboxylation of linkers under thermal and alkaline conditions, the self-loading of BC in MOFs can be realized by solvent vapor-assisted thermal treatment. Since water impurity causes limited self-conversion and excess organic solvent can purify MOFs, the BC-MOF materials maintain good crystallinity and even show superior porosity. link3 Owing to the increased specific surface areas, open metal sites, and alkalinity of BC, the prepared MOF composites exhibit substantially improved CO2 capture performance with good balance between capacity and selectivity. For example, after self-conversion with ethanol solvent, the CO2 adsorption capacity and CO2/N2 (15  85) selectivity at 298 K and 100 kPa increase from 3.7 mmol g-1 and 11.4 to 5.8 mmol g-1 and 29.2, respectively.The suitability as FRET probes of two bichromophoric 1-deoxydihydroceramides containing a labelled spisulosine derivative as a sphingoid base and two differently ω-labelled fluorescent palmitic acids has been evaluated. The ceramide synthase (CerS) catalyzed metabolic incorporation of ω-azido palmitic acid into the above labeled spisulosine to render the corresponding ω-azido 1-deoxyceramide has been studied in several cell lines. In addition, the strain-promoted click reaction between this ω-azido 1-deoxyceramide and suitable fluorophores has been optimized to render the target bichromophoric 1-deoxydihydroceramides. These results pave the way for the development of FRET-based assays as a new tool to study sphingolipid metabolism.Ensemble modeling has gained increasing attention for improving the performance of quantitative models in near infrared (NIR) spectral analysis. Based on Monte Carlo (MC) resampling, least absolute shrinkage and selection operator (LASSO) and partial least squares (PLS), a new ensemble strategy named MC-LASSO-PLS is proposed for NIR spectral multivariate calibration. In this method, the training subsets for building the sub-models are generated by sampling from both samples and variables to ensure the diversity of the models. In detail, a certain number of samples as sample subsets are randomly selected from training set. Then, LASSO is used to shrink the variables of the sample subset to form the training subset, which is used to build the PLS sub-model. This process is repeated N times and N sub-models are obtained. Finally, the predictions of these sub-models are used to produce the final prediction by simple average. The prediction ability of the proposed method was compared with those of LASSO-PLS, MC-PLS and PLS models on the NIR spectra of corn, blend oil and orange juice samples.