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Objective: Field trials were conducted in 13 citrus production regions including Hunan and Hubei provinces to evaluate the safety of the application of acetamiprid and pyriproxyfen on citrus. The residue, dissipation dynamics and dietary risk assessment of acetamiprid and pyriproxyfen in citrus fruit were investigated. Methods: The samples were extracted with 1% acetic acid in acetonitrile, purified using a mixture of primary secondary amine and graphitized carbon black, and detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Results: Excellent linearity (R2 > 0.99) was observed between the response peak area and the concentration of acetamiprid and pyriproxyfen in the range of 0.001–0.5 mg/L. In whole citrus fruit and flesh spiked at 0.01, 0.5 and 2.5 mg/kg, the recoveries of acetamiprid and pyriproxyfen ranged from 83.0% to 104.3% and from 74.8% to 98.7% with relative standard deviation (RSDs) of 3.8% to 10.0% and 2.0 to 6.0%, respectively. The limits of quantification (LOQs) for the analytes were both 0.01 mg/kg. The dissipation dynamics of acetamiprid and pyriproxyfen in whole citrus fruit was fitted to a first-order kinetics model. The degradation half-lives of acetamiprid and pyriproxyfen in whole citrus fruit were 5.1–15.8 days and 4.5–21.2 days, respectively. Twenty-seven percent acetamiprid-pyriproxyfen dispersible concentrate was sprayed twice on citrus at the recommended dosage of 500 g/hm2 (2 000 × dilution). At a 7-day safety interval, the residues of acetamiprid and pyriproxyfen in citrus fruit ranged from less than 0.01 mg/kg to 0.45 mg/kg and to 0.68 mg/kg, respectively. At a 10-day safety interval, the residues of acetamiprid and pyriproxyfen in citrus fruit ranged from less than 0.01 mg/kg to 0.40 mg/kg and to 0.56 mg/kg, respectively and were both lower than the maximum residue limits (MRLs) for acetamiprid (0.5 mg/kg) and pyriproxyfen (2.0 mg/kg) according to the Chinese national standard. The risk assessment results showed that the acute and chronic dietary exposure risk of acetamiprid and pyriproxyfen ranged from 0.0% to 53.0% (much lower than 100%) for people in different age groups, which was at an acceptable level. Conclusion: This study can provide guidance for the safety evaluation and rational application of acetamiprid and pyriproxyfen in citrus.

The expression pattern, functions, and detailed regulatory mechanisms of miR‐379 in laryngeal carcinoma remain unknown. In the present study, we aimed to uncover novel potential miR‐379 targets and shed light on its roles in laryngeal carcinoma. The expression level of miR‐379 was measured based on the data obtained from the TCGA database and the cell lines. After miR‐379 mimic transfection, cell proliferation, invasion and migration assay, and wound‐healing assay in HEp‐2 cell line were implemented to evaluate the effects of miR‐379 on laryngeal carcinoma in vitro. The target genes for miR‐379 in silico were predicted and validated using luciferase reporter assay. The miR‐379 expression level was reduced in laryngeal carcinoma tissues and cell lines. Moreover, miR‐379 overexpression inhibited the cell proliferation, migration, and invasion of laryngeal carcinoma cells. TCF‐4 was detected as a direct target of miR‐379 in laryngeal carcinoma. Furthermore, restored TCF‐4 expression rescued the inhibitory roles of miR‐379 overexpression on cell proliferation, migration, and invasion.Our study for the first time demonstrated that miR‐379/TCF‐4 might involve in the progression of laryngeal carcinoma, and miR‐379 appears to serve as a novel tumor suppressor in laryngeal carcinoma. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the hydrogenation and dehydrogenation behavior of Mg2Co nanoparticles and carbon nanotube (CNT) composites using temperature-programmed deposition, Raman spectroscopy, and X-ray diffraction (XRD). We used the mechanical alloying method to prepare nanosized Mg2Co particles on CNTs with three loadings of alloys. The introduction of CNTs showed dehydrogenation, hydrogen desorption starting at 370°C, with the majority of hydrogen being below 500°C. This can be explained by the fact that Mg2Co alloy deposited on CNT surface induced the dissociation of hydrogen into two atoms, which were spilt over and then intercalated into the interlayer of CNT. Accordingly, the atomic intercalation enabled the reduction of the hydrogen desorption activation barrier. The spillover mechanism of hydrogen storage can be confirmed by XRD and Raman spectroscopy because of larger interspacing (d 002) and weaker graphite degree (I D/I G) of CNTs after hydrogenation. [Copyright &y& Elsevier]

Abstract: This work investigates the synthesis of multilayered carbon nanotubes (CNTs) using the catalytic decomposition of acetylene at 700–850 °C over Fe- and Ni-supported Al2O3 catalysts in a fluidized bed reactor. Thermogravimetric analysis showed that the CNTs grown in a fluidized bed reactor have better thermal stability and higher production yield, compared to that in a fixed bed reactor. The CNT production yield increased with the growth temperature, and Fe-catalyst exhibited greater activity than Ni-catalyst in the formation of CNTs. According to Arrhenius plots, the apparent activation energies for the growth of CNTs were estimated to be 25.6 kJ/mol for Fe-catalyst and 65.6 kJ/mol for Ni-catalyst. The as-grown CNT products were characterized by high-resolution transmission electron spectroscopy, N2 physisorption, Raman spectroscopy, and X-ray diffraction. After purification, the CNT products were of the multilayered type, which were composed of perfect graphene layers. The results of this study demonstrate that the fluidized bed technology favors the large-scale production of CNTs with uniformity and at low cost. [Copyright &y& Elsevier]