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A simple continuous flow microreactor was successfully constructed for the N-oxidation of pyridine. The continuous flow microreactor used titanium silicalite (TS-1) in a packed-bed microreactor and H2O2 (in methanol as solvent) as the catalytic oxidation system for the formation of various pyridine N-oxides in up to 99% yields. This process is a safer, greener, and more highly efficiency process than using a batch reactor. The device was used for over 800 hours of continuous operation with the catalyst maintaining great activity thus providing great potential for large-scale production.

A novel reaction of propargylamines with aryl azides is designed for the synthesis of 5-amino-1,2,3-triazoles employing a one-pot strategy. In this process, base-mediated isomerization of propargylamines generates allenamine intermediates, which participate in a cyclization reaction with azides. Optimization of the reaction conditions revealed that t-BuOK as the base and DMF as the solvent gave the best yields. This protocol is expanded to different propargylamines and azides, with the results showing that 3-aryl propargylamines and aryl azides are tolerated to produce the corresponding 1,2,3-triazoles. This procedure provides a simple and efficient method to access a series of 5-amino-1,2,3-triazoles possessing a wide spectrum of functional groups.

Nitrogen-containing heterocycles are ubiquitous fragments of numerous natural products, pharmaceuticals, designed bioactive drug candidates and agrochemicals. During the past few decades, these compounds have received considerable attention from the synthetic chemistry community, and great efforts have been focused on the development of concise and efficient methods for the synthesis of these heterocyclic skeletons. In this review, we summarize a diverse range of synthetic methods employing β-aminovinyl esters(ketones) as key CC-N-synthons to furnish useful bioactive heterocyclic frameworks, such as quinolines, pyridines, pyrazines, pyrroles, indoles, oxazoles, imidazoles, thiazoles, isothiazoles, pyrazoles, triazoles, and azepines, thus offering new opportunities and expanding the toolbox of synthetic chemistry reactions.

Succinoglycan is an industrially important exopolysaccharide biosynthesized by bacteria. In this study, mutant strain 18052 N-11 was obtained from the wild type strain Rhizobium radiobacter ATCC 19358 by NTG mutagenesis. It has a high yield succinoglycan of 32.5 g/L cultured in a 15 L-fementer for 72 h. Succinoglycan SG-A from the wild type strain has two components, and the molecular weights were 1.55 × 107 Da and 1.26 × 106 Da, respectively. While, succinoglycan SG-N from the mutant strain was a homogeneous polysaccharide, and the molecular weight was 1.01 × 107 Da. The molecular weight of both succinoglycan was higher than those reported in literatures. DSC thermogram of SG-A showed a higher endothermic peak than that of SG-N due to the higher crystallinity of SG-A. The dynamic frequency sweep test of SG-A and SG-N showed that the elastic modulus G' and viscosity modulus G" curves intersected at 65 °C, indicating the thermally induced order-disorder conformation. The results of effect of concentrations (2.5–15%) and temperatures (25–75 °C) on apparent viscosity of SG-A and SG-N showed that the succinoglycan solutions exhibited non-Newtonian, shear-thinning behavior. Both SG-A and SG-N showed an excellent emulsification activity. The characterizations and rheological properties make SG-A and SG-N prominent candidates in food, cosmetics, pharmaceutical and petroleum industries.

Curdlan is a neutral linear exopolysaccharide produced by Agrobacterium spp. under nitrogen-limiting conditions. In this study, we explored the role of glnA in curdlan biosynthesis in Agrobacterium sp. CGMCC 11546. The curdlan production of the ΔglnA strain was impaired, decreasing by 93% compared with that of the wild-type strain after 96 h fermentation. Analysis of fermentation profiles revealed that cell growth and utilization of carbon and nitrogen sources were impaired in the ΔglnA strain. Transcriptome analysis indicated that various of genes involved in curdlan biosynthesis were downregulated after 24 h fermentation in the ΔglnA strain, particularly genes involved in heme synthesis and the electron transport chain, which are essential for energy generation. Metabolomics analysis revealed flavin adenine dinucleotide (FAD) and adenosine diphosphate (ADP) accumulation in the ΔglnA strain, suggesting insufficient energy supply. Furthermore, glnA overexpression led to an 18% increase in the curdlan yield of the ΔglnA mutant compared with that of the wild-type strain after 96 h fermentation. Taken together, the findings demonstrate that glnA plays a vital role in curdlan biosynthesis by supplying ATP via regulating the expression of genes involved in heme synthesis and the electron transport chain.

A periodate lithium-oxidized difunctionalisation of aryl alkenes with thiols and electron-rich aromatics was achieved, selectively affording more than thirty carbosulphenylated products. Both experiments and quantum chemical calculations demonstrated the radical-polar nature of the processes, and that 1,2-dithioethane and thiiranium ions might play the role of intermediates.

Curdlan is a water-insoluble exopolysaccharide produced by Agrobacterium species under nitrogen starvation. The curdlan production in the ΔmdeA, ΔmetA, ΔmetH, and ΔmetZ mutants of methionine biosynthesis pathway of Agrobacterium sp. CGMCC 11546 were significantly impaired. Fermentation profiles of four mutants showed that the consumption of ammonia and sucrose was impaired. Transcriptome analysis of the ΔmetH and ΔmetZ mutants showed that numerous differentially expressed genes involved in the electron transfer chain (ETC) were significantly down-regulated, suggesting that methionine biosynthesis pathway affected the production of energy ATP during the curdlan biosynthesis. Furthermore, metabolomics analysis of the ΔmetH and ΔmetZ mutants showed that ADP and FAD were significantly accumulated, while acetyl-CoA was diminished, suggesting that the impaired curdlan production in the ΔmetH and ΔmetZ mutants might be caused by the insufficient supply of energy ATP. Finally, the addition of both dibasic sodium succinate as a substrate of FAD recycling and methionine significantly restored the curdlan production of four mutants. In conclusion, methionine biosynthesis pathway plays an important role in curdlan biosynthesis in Agrobacterium sp. CGMCC 11546, which affected the sufficient supply of energy ATP from the ETC during the curdlan biosynthesis.

A general procedure of 1,2-dibromination of vicinal sp

A formal hydroxylation/cyclization of cyclopropanemethanols with DMSO is described, which involves isomerization and cyclization under Tf

Using NaClO2 pretreated Calotropis gigantea fiber (CGF) as the bio-template, three N-polymer functionalized fibers were fabricated by in-situ growth of polydopamine (PDA), polyaniline (PAN) and poly(m-phenylenediamine) (PmPD) along the fiber. The resulting adsorbents were applied to remove perfluorooctanoic acid (PFOA) from water. The adsorption process reached equilibrium within 3 h, and the maximum adsorption capacity was 207.3–232.8 mg/g. Electrostatic attraction, hydrogen bond and hydrophobic interaction participated in the adsorption process. Three adsorbents could be well regenerated, and the recovered adsorbents maintained higher adsorption percentage (≥80%) after five adsorption-desorption cycles. Among three adsorbents, PAN-CGF displayed remarkable adsorption performance on perfluorochemicals removal.

The Reshian area lies in the Lesser Himalayas (LH) in Jhelum valley, Azad Kashmir. The present study is carried out to investigate detailed petrological, geochemical, and geochronological characterization of granitic gneiss. Petrological investigation exhibits that the protoliths of Rashian granitic gneiss (RGG) are syenogranite to monzogranite. Geochronological study infers the protoliths formed in the Neoproterozoic (823 ± 14 Ma and 843 ± 12 Ma), representing the crystallization age of early granitic magma. Petrographical and geochemical study suggests the characteristics of the RGG are S-type, less Si, rich K, depletion in rare earth element (REE), the enrichment of light rare earth element (LREE), negative Eu anomaly, alkali to alkali-calcic, and peraluminous to slightly metaluminous granite. Meanwhile, the study implies the source of the RGG was derived mainly from partial melting of greywacke. Moreover, they have initial 87Sr/86Sr ratios ranging from 0.705823 to 0.714078, and initial eNd values varying from − 34.3079 to − 15.1398, revealing that the magma of the RGG was sourced from the fractional melting of the crustal material. Additionally, the RGG was emplaced in the post-collisional setting with the nature of syn-collisional granites and volcanic arc granites, implied probably due to the thermal perturbation associated with the breakup of the Rodinian supercontinent.

All-metal self-supported cathodes, especially porous noble metals, are attractive alternatives for settling the issue of carbon- and binder-decomposition in Li–O2 batteries. However, the high cost of noble metals hinders their practical application. In the present study, nanoporous Ti foam is prepared using a molten Mg corrosion method for the first time. Electron microscope images demonstrate that, nanoporous Ti foam is obtained by treating Ti-Mo alloy plates in molten Mg at 650 °C for 3 hours. Then, the foam is coated with a layer of Au nanoparticles by cool-sputtering and used as self-supported Li–O2 battery cathodes. The nanoporous foam can decrease the consumption of gold markedly compared with traditional porous Au foam. Benefiting from the high stability, conductivity, and porosity of Ti foam, the Li–O2 batteries exhibit good durability (cycling 118 rounds at 1C rate within a 1000 mAh g−1 capacity limitation).

Ti nanowire arrays vertically standing on Ti foam prepared by a facile corrosion method were used as self-supported Li–O2 battery cathodes. The batteries exhibited enhanced durability at high rate current densities (e.g. cycling 640 times at 5 A g−1).

MoO3 nanoparticles were electrodeposited on Ti nanorod arrays. The “sea cucumber”-like Ti@MoO3 nanorod arrays showed enhanced rate capability (300 mA h g−1 at 100 A g−1) and excellent durability (retaining 300 mA h g−1 after 1500 cycles at 20 A g−1) as self-supported Li ion battery anodes.

RuO2 modified TiO2 nanotube arrays, growing on Ti foams, are used as carbon and binder free cathodes for Li–O2 batteries. The micrometer pores in Ti foams and nanometer pores in TiO2 nanotubes supply facilitated transport channels for oxygen diffusing into/out of the catalysts in discharge and charge processes. The RuO2 catalyst exhibits outstanding catalytic active toward oxygen evolution reaction (OER), which leads the charge voltage maintaining around 3.7 V all through the battery cycling. The stability of TiO2/Ti support, abundant oxygen transport path and favorable catalytic activity of RuO2 toward OER enable the Li–O2 batteries exhibiting 130 cycle discharge/charge.

The hypothesis that the joint effects of predation and cyanobacteria favor the performance of small-bodied cladocerans relative to large-bodied species was tested using three competition experiments in a two-factor full-factorial design. The largebodied Daphnia pulex outcompeted the medium-bodied Simocephalus vetulus when fed a green alga Chlorella pyrenoidosa. However, the presence of the toxic cyanobacterium Microcystis aeruginosa and the coelenterate predator Hydra oligactis reversed the competitive outcome. Their joint effect was significant and contributed to the strongest dominance of S. vetulus. Similar dominance shifts were also observed in the competition between D. pulex and the small-bodied Bosmina longirostris, and in the competition between S. vetulus and B. longirostris. Life table and predation experiments showed that the order of sensitivity of three cladoceran species to Microcystis and to Hydra was the same as the order of competitive superiority in the absence of cyanobacteria. Therefore, cyanobacteria, predation and their joint effects are important drivers for competitive outcomes among cladocerans, potentially creating new opportunities for small-bodied species to dominate in a community. The present study underscores the importance of considering the combined effects of dietary palatability and predation on competitive dominance among herbivores, when predicting zooplankton responses to frequent cyanobacterial blooms.

A novel and efficient I2-catalyzed oxidative tandem cyclization of simple vinyl azides and benzylamines has been developed for the synthesis of substituted imidazoles. In this reaction, various substituted groups on vinyl azides and benzylamines proceed smoothly and the desired imidazoles are obtained in moderate to good yields.

The traffic matrix (TM) is essential in network planning and traffic engineering tasks. Lots of models and methods are proposed to estimate the network overall traffic matrix from link measurements. However because of the limits of the link measurements, the estimation on overall traffic matrix from link measurements based on these prior model assumptions do not perform well for large-scale networks. It has been proved the probability model can reconstruct the traffic matrix from limited link measurements with small bias. The probability model-based estimation is also extended to large-scale networks. We compare the probability model with the classical gravity model using real data of the Abilene network. It demonstrates the probability model is applicable in real networks. Finally we propose a model that combines the probability model and the gravity model. It is proved the performance of TM estimation based on this model is better than that based on two sole models separately.

186m Ta and 186 Ta have been produced by irradiation of nat W with 14 MeV neutrons. The unreported tantalum isomer 186m Ta has been identified by means of measuring known γ rays from 186 Ta β-decay. The half-life of 186m Ta has been determined to be 1.54±0.05 min.