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In this study, the silver-exchanged heteropolyacids were prepared by a simple and environmentally friendly ion exchange method, were found to be active in the esterification of oleic acid with methanol to produce biodiesel. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), separately. The effect of various factors was investigated to optimize the reaction conditions. The results showed that the oleic acid conversion can reach 91.3% after reacting for 3 h at 70°C, with oleic acid to methanol ratio of 1:10 and the amount of catalyst of 5 wt.%. Moreover, the catalyst could be easily separated from the reaction mixture and used repeatedly for five cycles with the oleic acid conversion over 50.1%, due to its relative stability. In particular, this catalyst can also catalyze other esterification of fatty acids with different chain length of carboxylic acid and high acid value non-edible oils, which may provide significant benefits for developing an environmentally benign and continuous process for synthesizing biodiesel in the future. [ABSTRACT FROM AUTHOR]

A solid-state mechanochemical route for rapid synthesis of MgAl layered double hydroxide (LDH) nanosheets large in surface area and decorated with abundant hydroxyl groups was developed for catalytic elimination of carbonyl sulfide and H2S, showing activity superior to those of commercial LDHs and porous metal oxides. [ABSTRACT FROM AUTHOR]

GdAlO3:Er3+, Yb3+ phosphors doped with Lu3+, Ga3+ ions were prepared via coprecipitation. The influences of substituting Ga3+ for Al3+ and substituting Lu3+ for Gd3+ on the structure and upconversion photoluminescence (UCPL) of the phosphors were studied. The experimental results show that the crystal textures did not change but the lattice parameters changed slightly via Lu3+, Ga3+ doping. This results in a decrease in the host phonon energy and a marked improvement in the green emission spectrum at 546nm. Moreover, the amounts of surface CO2, CO32-, and OH- species gradually decreased with Lu3+, Ga3+ doping. The combined effects led to an improvement in the UCPL efficiency with Ga3+, Lu3+ doping. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1), with the strong toxicity and carcinogenicity, has been reported to great toxicity to the liver and other organs of animals. It cause huge economic losses to breeding industry, including the aquaculture industry. Chinese mitten crabs (Eriocheir sinensis), as one of important species of freshwater aquaculture in China, are deeply disturbed by it. However, the molecular and metabolic mechanisms of hepatopancreas and ovary in crabs underlying coping ability are still unclear. Hence, we conducted targeted injection experiment with or without AFB1, and comprehensively analyzed transcriptome and metabolomics of hepatopancreas and ovary. As a result, 210 and 250 DEGs were identified in the L-C vs. L-30 m and L-C vs. L-60 m comparison, among which 14 common DEGs were related to six major functional categories, including antibacterial and detoxification, ATP energy reaction, redox reaction, nerve reaction, liver injury repair and immune reaction. A total of 228 and 401 DAMs in the ML-C vs. ML-30 m and ML-C vs. ML-60 m comparison both enriched 12 pathways, with clear functions of cutin, suberine and wax biosynthesis, tyrosine metabolism, purine metabolism, nucleotide metabolism, glycine, serine and threonine metabolism, ABC transporters and tryptophan metabolism. Integrated analysis of metabolomics and transcriptome in hepatopancreas discovered three Co-enriched pathways, including steroid biosynthesis, glycine, serine and threonine metabolism, and sphingolipid metabolism. In summary, the expression levels and functions of related genes and metabolites reveal the regulatory mechanism of Chinese mitten crab (Eriocheir sinensis) adaptability to the Aflatoxin B1, and the findings contribute to a new perspective for understanding Aflatoxin B1 and provide some ideas for dealing with it. [ABSTRACT FROM AUTHOR]

TCP Vegas performance can be improved since its rate-based congestion control mechanism could proactively avoid possible congestion and packet losses in multi-hop ad hoc networks. Nevertheless, Vegas cannot make full advantage of available bandwidth to transmit packets since incorrect bandwidth estimates may occur due to frequent topology changes caused by node mobility. This paper proposes an improved TCP Vegas based on the grey prediction theory, named TCP-Gvegas, for multi-hop ad hoc networks, which has the capability of prediction and self-adaption, as well as three enhanced aspects in the phase of congestion avoidance. The lower layers' parameters are considered in the throughput model to improve the accuracy of theoretical throughput. The prediction of future throughput based on grey prediction is used to promote the online control. The optimal exploration method based on Q- Learning and Round Trip Time quantizer are applied to search for the more reasonable changing size of congestion window. Besides, the convergence analysis of grey prediction by using the Lyapunov's second method proves that a shorter input data length of prediction implies a faster convergence rate. The simulation results show that the TCP-Gvegas achieves a substantially higher throughput and lower delay than Vegas in multi-hop ad hoc networks. [ABSTRACT FROM AUTHOR]

There is limited study to simultaneously determine the relative bioavailability of heavy metals such as Cd, Pb, Cu, Cr(VI), and Ni in soil samples. In the present study, the bioaccessibility of heavy metals using in vitro assay was compared with the relative bioavailability of heavy metals using in vivo mouse model. The bioaccessibility of heavy metals ranged from 9.05 ± 0.97 % (Cr) to 42.8 ± 3.52 % (Cd). The uptake profile of heavy metals in soil and solution samples in mouse revealed that the uptake kinetics could be fitted to a two-compartment model. The relative bioavailability of heavy meals ranged from 34.8 ± 7.0 % (Ni) to 131 ± 20.3 % (Cu). Poor correlation between bioaccessibility and relative bioavailability of heavy metals was observed ( r = 0.11, p > 0.05). The relative bioavailability of heavy metals was significantly higher than the bioaccessibility of heavy metals ( p < 0.05). The present study indicated that the in vitro digestion method should be carefully employed in risk assessment. [ABSTRACT FROM AUTHOR]