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Natural biomolecules have been used extensively as chiral scaffolds that bind/surround metal complexes to achieve stereoselectivity in catalytic reactions. ATP is ubiquitously found in nature as an energy-storing molecule and can complex diverse metal cations. However, in biotic reactions ATP-metal complexes are thought to function mostly as co-substrates undergoing phosphoanhydride bond cleavage reactions rather than participating in catalytic mechanisms. Here, we report that a specific Cu(II)-ATP complex (Cu 2+ ·ATP) efficiently catalyses Diels-Alder reactions with high reactivity and enantioselectivity. We investigate the substrates and stereoselectivity of the reaction, characterise the catalyst by a range of physicochemical experiments and propose the reaction mechanism based on density functional theory (DFT) calculations. It is found that three key residues (N7, β-phosphate and γ-phosphate) in ATP are important for the efficient catalytic activity and stereocontrol via complexation of the Cu(II) ion. In addition to the potential technological uses, these findings could have general implications for the chemical selection of complex mixtures in prebiotic scenarios. ATP acts as a co-substrate in enzyme catalysed reactions, but can also specifically bind metal ions. Here, the authors show that ATP interacts with copper ions and forms a Cu(II)-ATP complex that efficiently catalyses Diels-Alder reactions, and determine ATP residues that are essential for this activity.

The performance of foaming agent plays a key role in the forming quality of foamed concrete. In order to overcome the limitation of single composition of traditional foaming agent, this paper adopts the research method of multicomponent composite combined with the foaming theory and preparation technology of foaming agent, a new protein composite foaming agent was prepared using a mixture of anionic surfactant (SCA), nonionic surfactant (APG), and foam stabilizer (AR), and then, the effects of different surfactant mass ratios and foam stabilizer concentrations on the properties of composite foaming agent were studied by a series of tests. The results show that the optimal mass ratio of surfactants is mAPG: mSCA = 2 : 1, and the optimal concentration of foam stabilizer is 0.5 g/L, which verified that the self-made composite foaming agent system in this paper has the advantages of strong foaming ability, excellent foam stability, and low cost. In addition, foamed concrete was prepared on the basis of the optimized composite foaming agent system, and the influence rules of different foaming agent solution volumes, water-cement ratios, and diatomite dosages on the performance of foamed concrete were revealed through laboratory tests and SEM images. At the same time, the optimal ratio of each component required for the preparation of high-quality foamed concrete was further obtained by using the response surface analysis of compressive strength. The research results provide an important reference for the preparation of high-performance foamed concrete and corresponding foaming agent, which is beneficial for solving the disadvantages of poor foam stability in the existing foaming agents and improving the application level of foamed concrete in engineering construction.

Solid dispersion (SD) is a useful approach to improve the dissolution rate and bioavailability of poorly water-soluble drugs. This work investigated the effects of carrier material lipophilicity and preparation method on the properties of andrographolide (AG)–SD. The SDs of AG and the carrier materials, polyethylene glycol (PEG) and PEG grafted with carbon chains of different length (grafted PEG), have been prepared by spray-drying and vacuum-drying methods. In AG–SDs prepared by the different preparation methods with the same polymer as carrier material, the intermolecular interaction, 5% weight-loss temperature, the melting temperature (Tm), surface morphology, crystallinity, and dissolution behavior have significant differences. In the AG–SDs prepared by the same spray-drying method with different grafted PEG as carrier material, Tm, surface morphology, crystallinity, and dissolution behavior had little difference. In the AG–SDs prepared by the same vacuum-drying method with different grafted PEG as carrier material, the crystallinity and Tm decreased, and the dissolution rate of AG increased with the increase of grafted PEG lipophilicity. The preparation method has an important effect on the properties of SD. The increase of carrier material lipophilicity is beneficial to the thermal stability of SD, the decrease of crystallinity and the increase of dissolution rate of a poorly water-soluble drug in the SD.

The ratio between the reactivity of HC and NOx, i.e., φ = ∑kOH＋HC, [HCi] / （kOH＋No[NO] ＋ kOH＋NO2 [NO2]）, is used to study the chemistry of HOx radicals （HOE and OH） in the marine boundary layer （MBL）. Data analysis shows that HOx production and OH/HO2 ratio strongly depend on φ. The OH radical concentration presents an ascending tendency in low φ region but a de- clining one in high ∞ region, while HO2 radical increases with increasing φ under low φ conditions but appears to be nearly constant with the variation of ∞ under high φ conditions. The observed OH/HO2 ratio shows a continuous decrease with the increase of φ. Model studies are conducted to illuminate the behavior of HOx radicals in different φ regions, and the results represent general agreement with the observed variations of HOx radicals and can well explain the observed behavior of HOx radicals. This study demonstrates that φ could be used as an efficient parameter to ascertain the behavior of HOx radicals in the clean marine boundary layer.

A Back-Propagation Neural Network (BPNN) was established to predict the daytime variations of HO 2 radical concentration observed in the field campaign RISFEX 2003 (RIShiri Fall Experiment 2003) conducted in September 2003 at Rishiri Island (45.07 N, 141.12 E, and 35m asl) in the Sea of Japan. The initial weight matrices and bias vectors for the network were optimized by a bee evolutionary genetic algorithm (BEGA). It was found that the input variables sensitive to HO 2 variation were photolysis frequency of O 3 to O( 1 D) ( J (O 1 D)), a composite parameter defined as the ratio of HC to NO x reactivity towards OH radicals ( Φ ), and the total aerosol surface area ( A ). The predicted results are closely correlated with the experimental data with the coefficient of determination ( R 2 ) close to 1. In addition, the means and ranges of the predicted HO 2 concentration agree with the observed data with the correlation coefficient ( R ), the index of agreement (IA) and the fractional bias (FB) in the range of 0.84–0.93, 0.88–0.95 and −14%–7%, respectively. This study demonstrates that BPNN is a potential tool to predict the daytime variations of HO 2 radical concentrations in the marine boundary layer (MBL).

Novel polyurethane (PU) scaffold materials were designed and prepared on the basis of a coupling reaction between tetra-hydroxyl-terminated poly(butadiene-co-acrylonitrile) prepolymer (THTPBA) and poly(ethylene glycol) (PEG) via 1,6-hexamethylene diisocyanate as anchor molecule. The hydrophilicity, degradability, mechanical, and biomedical properties of the THTPBA/PEG PU materials were scrutinized by swelling and goniometry, FTIR and gravimetry methods, tensile stress–strain measurements and hemolysis, platelet activation, dynamic (erythrocyte aggregation) and static coagulation as well as MTT assays. The experimental results indicated that the hydrophilicity and mass loss were enhanced with increased concentrations and molecular weight (MW) of PEG. The degradation may be attributable to the cleavage of urethane or ester bonds in polymer chains. The in vitro blood compatibility and MTT cytotoxicity investigations elicited that the MW of PEG and mass ratios of THTPBA to PEG had important influence on the biomedical properties. The tensile stress–strain investigations showed that the highly crosslinked architecture offered high elastic modulus and mechanical strength. The PU scaffolds with proper component ratios and MW of PEG exhibited improved mechanical properties and biocompatibility as well as low toxicity, and can be employed as potential candidates for blood-contacting applications.

Ce/Nd-containing UiO-7 molecular sieves were ionothermally synthesized in imidazole–tetramethylammonium chloride eutectic mixture. The reaction conditions were systematically investigated. It is concluded that the crystallinity of products changes with Ce(Nd)/Al ratios and crystallization temperature. The morphologies and properties of Me-UiO-7 (Me = Ce, Nd) were characterized through X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV-Vis), Brunauer–Emmett–Teller (BET) and thermogravimetric analysis (TG). The results indicate that hetero atom Ce and Nd occupy the sites of Al in crystal lattice of molecular sieves by isomorphous replacement and partially entered the framework of UiO-7 molecular sieve. The morphology of Ce-UiO-7 is rectangular columnar with smooth surface, and the morphology of Nd-UiO-7 leaf-like with rough surface. The thermal stability of Ce-UiO-7 and Nd-UiO-7 are both superior to UiO-7. The BET surface areas of Ce-UiO-7 and Nd-UiO-7 are also larger than that of UiO-7.

The development process and characteristic analysis of precipitation cloud system is an important issue in the field of cloud precipitation physics. Here, the 700 hPa Cloud Water Content (CWC) and the 1h value of airflow velocity (omega, OMG) in the vertical direction of the atmosphere are used to measure the chaos degree of CWC distribution via the information entropy and judge the cloud development via OMG time series, hence a combined prediction model is proposed based on hybrid multi-scale decomposition, Holt model, Autoregressive Integrated Moving Average model (ARIMA) and Lagrange Multiplier. The results show that, the CWC entropy has nonlinear and non-stationary characteristics; the clouds over the north have smaller means of the CWC entropy sequence and larger variance compared with those over the south regardless of the cloud development stage; a good temporal corresponding relationship is found between the regional average OMG and the extreme point reconstructed by the wavelet low-frequency of the C