New insight into the catalytic mechanism of ester hydrogenation over the Cu/ZnO catalyst: the contribution of hydrogen spillover.

The dimethyl maleate hydrogenation activity of Cu, ZnO-X and physically mixed Cu+ZnO-X samples was systematically investigated to probe the essential role of ZnO in ester hydrogenation processes. Cu samples exhibited high CC bond hydrogenation ability with dimethyl succinate as the main product. Comparatively, ZnO was inactive in hydrogenation due to its weak ability to dissociate hydrogen while the CO group could be activated and adsorbed on the ZnO surface. Interestingly, physical mixing with ZnO significantly improved the CO hydrogenation activity of Cu samples. The H2-TPD results reveal the origin of "Cu-ZnO synergy": hydrogen atoms formed on the copper surface can spill over to the ZnO surface and react with the adsorbed CO group.

Effects of Compound Probiotics on Cecal Microbiota and Metabolome of Swine.

Complex probiotics are made from various single probiotics mixed in scientific formula. The long-term intake of different probiotics is beneficial to maintain the intestinal microecological balance, inhibiting harmful pathogenic flora and facilitating organism health. Based on the limited research on intestinal flora and related metabolites after the long-term intake of the probiotic complex, in this study, 16S rRNA gene sequencing and untargeted metabolomics were used to further investigate the effects of the probiotic complex on the intestinal flora and metabolome of pigs. The results demonstrated that the content of flora in the intestinal tract or metabolites of pigs varied greatly and was related to cellular metabolic pathways after the long-term feeding of complex probiotics. This study provides a valuable theoretical basis for farmers to raise pigs scientifically and healthily.

An Efficient Way to Model Complex Iron Carbides: A Benchmark Study of DFTB2 against DFT.

Iron carbides have attracted increasing attention in recent years due to their enormous potential in catalytic fields, such as Fischer-Tropsch synthesis and the growth of carbon nanotubes. Theoretical calculations can provide a more thorough understanding of these reactions at the atomic scale. However, due to the extreme complexity of the active phases and surface structures of iron carbides at the operando conditions, calculations based on density functional theory (DFT) are too costly for realistically large models of iron carbide particles. Therefore, a cheap and efficient quantum mechanical simulation method with accuracy comparable to DFT is desired. In this work, we adopt the spin-polarized self-consistent charge density functional tight-binding (DFTB2) method for iron carbides by reparametrization of the repulsive part of the Fe-C interactions. To assess the performance of the improved parameters, the structural and electronic properties of iron carbide bulks and clusters obtained with DFTB2 method are compared with the previous experimental values and the results obtained with DFT approach. Calculated lattice parameters and density of states are close to DFT predictions. The benchmark results show that the proposed parametrization of Fe-C interactions provides transferable and balanced description of iron carbide systems. Therefore, spin-polarized DFTB2 is valued as an efficient and reliable method for the description of iron carbide systems.

Exploring the Protective Effects and Mechanism of Huaji Jianpi Decoction against Nonalcoholic Fatty Liver Disease by Network Pharmacology and Experimental Validation.

This paper was designed to predict the mechanisms of the active components of Huaji Jianpi Decoction (HJJPD) against nonalcoholic fatty liver disease (NAFLD) based on network pharmacology-combined animal experiments. The candidate compounds of HJJPD and its relative targets were obtained from TCMSP and PharmMapper web server, and the intersection genes for NAFLD were discerned using OMIM, GeneCards, and DisGeNET. Then, the target protein-protein interaction (PPI) and component-target-pathway networks were constructed. Moreover, gene function annotation (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed to study the potential signaling pathways associated with HJJPD's effect on NAFLD. Molecular docking simulation was preformed to validate the binding affinity between potential core components and key targets. Eventually, the candidate targets, the possible pathway, and the mechanism of HJJPD were predicted by the network pharmacology-based strategy, followed by experimental validation in the NAFLD mice model treated with HJJPD. A total of 55 candidate compounds and 36 corresponding genes were identified from HJJPD that are associated with activity against NAFLD, and then the network of them was constructed. Inflammatory response and lipid metabolism-related signaling pathways were identified as the critical signaling pathways mediating the therapeutic effect of the active bioactive ingredients on NAFLD. Compared with the model group, the liver wet weight, liver/body ratio, the levels of total cholesterol (TC), triglyceride (TG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and high-density lipoprotein (HDL) in serum in the HJJPD low-dose (17.52 g/kg·d), medium-dose (35.04 g/kg·d), and high-dose (70.07 g/kg·d) groups significantly decreased (P < 0.05). Light microscope observation shows that HJJPD could control the degree of lipid denaturation of the mouse liver tissue to a great extent. RT-qPCR results show that the mRNA expression levels of peroxisome proliferative activated receptor gamma (PPARG), tumor necrosis factor-α (TNF-α), antiserine/threonine protein kinase 1 (AKT1), and prostaglandin-endoperoxide synthase (PTGS2) in the liver tissues of the three HJJPD groups (17.52 g/kg·d, 35.04 g/kg·d, and 70.07 g/kg·d) were significantly lower than those in the model group (P < 0.05). HJJPD can exert its effect by inhibiting hepatic steatosis and related mRNA expression and decreasing the levels of other liver-related indexes. This study suggested that HJJPD exerted its effect on NAFLD by modulating multitargets with multicompounds through multipathways. It also demonstrated that the network pharmacology-based approach might provide insights for understanding the interrelationship between complex diseases and interventions of HJJPD.

Enhanced nitrogen removal from low C/N wastewater using biodegradable and inert carriers: Performance and microbial shift.

This work aims at investigating the enhancing effect of biodegradable and inert carriers on nitrogen removal from low C/N wastewater and revealing temporal changes in community succession. Natural corncobs and commercial fibers were used as biodegradable and inert carriers, respectively. Results showed that the TN removal efficiency was enhanced by 24% and 8.98% using biodegradable and inert carriers, respectively. For corncob carriers, denitrifiers achieved an obvious enrichment and reached a peak on the 30th day. On contrast, inert carriers were more favorable for the enrichment of nitirifiers. Additionally, the dominant denitrifying genus in the corncob system had changed to Dechloromonas, while it remained as Thauera at inert carriers. Finally, the potential coupling pattern of corncob conversion with denitrification in the corncob system was proposed based on the relevant functional enzymes. This work promotes a comprehensive understanding about carrier-enhanced nitrogen removal systems.

Solid Base Bi24 O31 Br10 (OH)δ with Active Lattice Oxygen for the Efficient Photo-Oxidation of Primary Alcohols to Aldehydes.

The selective oxidation of primary alcohols to aldehydes by O2 instead of stoichiometric oxidants (for example, MnVII , CrVI , and OsIV ) is an important but challenging process. Most heterogeneous catalytic systems (thermal and photocatalysis) require noble metals or harsh reaction conditions. Here we show that the Bi24 O31 Br10 (OH)δ photocatalyst is very efficient in the selective oxidation of a series of aliphatic (carbon chain from C1 to C10 ) and aromatic alcohols to their corresponding aldehydes/ketones under visible-light irradiation in air at room temperature, which would be challenging for conventional thermal and light-driven processes. High quantum efficiencies (71 % and 55 % under 410 and 450 nm irradiation) are reached in a representative reaction, the oxidation of isopropanol. We propose that the outstanding performance of the Bi24 O31 Br10 (OH)δ photocatalyst is associated with basic surface sites and active lattice oxygen that boost the dehydrogenation step in the photo-oxidation of alcohols.

High coverage adsorption and co-adsorption of CO and H2 on Ru(0001) from DFT and thermodynamics.

The adsorption and co-adsorption of CO and H2 at different coverages on p(4 × 4) Ru(0001) have been computed using periodic density functional theory (GGA-RPBE) and atomistic thermodynamics. Only molecular CO adsorption is possible and the saturation coverage is 0.75 ML (nCO = 12) with CO molecules co-adsorbed at different sites and has a hexagonal adsorption pattern as found by low energy electron diffraction. Only dissociative H2 adsorption is possible and the saturation coverage is 1 ML (nH = 16) with H atoms at face-centered cubic sites. The computed CO and H2 desorption patterns and temperatures agree reasonably with the experiments under ultrahigh vacuum conditions. For CO and H2 co-adsorption (nCO + mH2; n = 1-6 and m = 7, 6, 5, 5, 3, 1), CO pre-coverage affects H adsorption strongly, and each pre-adsorbed CO molecule blocks 2H adsorption sites and H2 does not adsorb on the surface with CO pre-coverage larger than 0.44 ML (nCO = 7); all these are in full agreement with the experiments under ultrahigh vacuum conditions. Our results provide the basis for exploring the mechanisms of catalytic conversion of synthesis gas.

Effect of pressure on the selectivity for the esterification of ethylene glycol with propionic acid in supercritical CO2.

The esterification of ethylene glycol with propionic acid was investigated in supercritical CO2 at 50.0 degrees C. The effect of pressure on equilibrium conversion and selectivity of ethylene glycol monopropionate (monoester) and ethylene glycol dipropinonate (diester) was studied systematically. It was shown that the equilibrium conversion and selectivity was nearly independent of pressure as pressure was lower than 9 MPa. At higher pressure, however, the yield and selectivity of the diester increased considerably, while those of the monoester decreased with increasing pressure. The main reason was that reactants and products distributed between the vapor phase and liquid phase at higher pressures. The solvent power of CO2 for the diester is stronger than that for the monoester. More diester molecules in the liquid phase were extracted into the vapor at higher pressures, which shifted equilibrium of the consecutive reversible reactions.

[Analysis of oxygenates from fischer-Tropsch synthesis oil using column liquid chromatography and gas chromatography-mass spectrography].

A liquid chromatographic column filled with silica gel of 100 - 200 mesh was used to separate cold trap oil from Fischer-Tropsch synthesis with dimethylsulfoxide (DMSO) as eluent. With this pretreatment method, the cold trap oil was separated into two major classes, namely, hydrocarbons and oxygenates. Minor components were also enriched and determined, and small peaks adjacent to big peaks and tailings were also well solved. The oxygenates were then analyzed with gas chromatography-mass spectrometry (GC-MS), and 139 components were identified.

A novel route for synthesis of gamma-butyrolactone through the coupling of hydrogenation and dehydrogenation.

A coupling process of the hydrogenation of maleic anhydride and the dehydrogenation of 1,4-butanediol has been invented for the synthesis of gamma-butyrolactone over a Cu-Zn catalyst, realizing optimal hydrogen utilization and better energy efficiency.