Search

As a result of antibiotic overuse, bacterial antibiotic resistance has become a severe threat to worldwide public health. The development of more effective antimicrobial therapies and alternative antibiotic strategies is urgently required. The role played by bacterial membrane vesicles (BMVs) in antibiotic resistance has become a current focus of research. BMVs are nanoparticles derived from the membrane components of Gram-negative and Gram-positive bacteria and contain diverse components originating from the cell envelope and cytoplasm. Antibiotic stress stimulates the secretion of BMVs. BMVs promote and mediate antibiotic resistance by multiple mechanisms. BMVs have been investigated as conceptually new antibiotics and drug-delivery vehicles. In this article, we outline the research related to BMVs and antibiotic resistance as a reference for the intentional use of BMVs to combat antibiotic resistance. [ABSTRACT FROM AUTHOR]

Herein, cobalt-reduced graphene oxide (rGO) catalyst was synthesized with a practical impregnation–calcination approach for the selective hydrodeoxygenation (HDO) of guaiacol to cyclohexanol. The synthesized Co/rGO was characterized by transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), and H2 temperature-programmed reduction (H2-TPR) analysis. According to the comprehensive characterization results, the catalyst contains single Co atoms in the graphene matrix and Co oxide nanoparticles (CoOx) on the graphene surface. The isolated Co atoms embedded in the rGO matrix form stable metal carbides (CoCx), which constitute catalytically active sites for hydrogenation. The rGO material with proper amounts of N heteroatoms and lattice defects becomes a suitable graphene material for fabricating the catalyst. The Co/rGO catalyst without prereduction treatment leads to the complete conversion of guaiacol with 93.2% selectivity to cyclohexanol under mild conditions. The remarkable HDO capability of the Co/rGO catalyst is attributed to the unique metal–acid synergy between the CoCx sites and the acid sites of the CoOx nanoparticles. The CoCx sites provide H while the acid sites of CoOx nanoparticles bind the C-O group of reactants to the surface, allowing easier C-O scission. The reaction pathways were characterized based on the observed reaction–product distributions. The effects of the process parameters on catalyst preparation and the HDO reaction, as well as the reusability of the catalyst, were systematically investigated. [ABSTRACT FROM AUTHOR]

Although port-city interaction and sustainability are becoming increasingly essential, prospering regional economy and facilitating international shipping trade, problems of their mismatch and incoordination have also been aroused. Thus, research on their relationship is necessary to generate profound enlightenment on how to achieve healthy and benign development for ports and cities. In this paper, a typical Chinese port-city group, six ports and their corresponding port cities in Liaoning are selected as research objects. Firstly, a grey relative relational model and a coupling coordination degree model based on entropy weight method are applied to analyse the port-city interactive trend and degree as well as exploring the relative impacts among internal factors in port and city subsystems. Then, a sustainability analysis box of correlation–coordination is constructed to further investigate the sustainable development status. Finally, strategies for the port-city sustainable development are proposed. The results indicate the six port-city systems have not strongly correlated and are in the stage of coordinated development. Only Dalian and Yingkou have realized sustainable development. Thus, there is still much room for improvement. Measures such as resources integration and dislocation development should be taken into account to optimize the sustainable and coordinated development of the port-city systems. [ABSTRACT FROM AUTHOR]

In this work, the reaction mechanism for the conversion of CO2 and H2 to methanol has been researched by density functional theory (DFT). The production of methanol from CO2 and H2 is catalyzed by a univocal bifunctional pincer-type complex trans-RuH2(CO)(dpa) (dpa = bis-(2-diphenylphosphinoethyl)amine). The reaction mechanism includes three continuous catalytic processes: (1) CO2 is converted to formic acid; (2) formic acid is converted to formaldehyde and water; (3) formaldehyde is converted to methanol. By computing the catalytic processes, we have shown that the rate-limiting step in the whole process is the direct cleavage of H2. The calculated largest free energy barrier is 21.6 kcal/mol. However, with the help of water, the free energy barrier can be lowered to 12.7 kcal/mol, which suggests viability of trans-RuH2(CO)(dpa) as a catalyst for the direct conversion of CO2 and H2 to methanol. [ABSTRACT FROM AUTHOR]