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Phytic acid, the principal storage form of phosphorus in wheat, plays both beneficial and anti-nutrient functions for human-being, and its analytical method still needs further development. In this work, we have developed a new method for the determination of phytic acid in wheat products based on derivatization with (trimethylsilyl)diazomethane in combination with liquid chromatography-mass spectrometry analysis. Methyl esterification greatly decreased the polarity and the acidity of phytic acid, and thus the corresponding derivative can be easily analyzed by liquid chromatography-mass spectrometry under common conditions. Furthermore, treatment with cation exchange resin removed the polyvalent metal ions in the solutions, and thus derivatization of phytic acid can be achieved efficiently and completely. The standard curve for phytic acid has been well established in the linear range of 0.5∼100 ng/mL with squared correlation coefficient more than 0.999, and the quantification limit of 0.25 ng/mL. The phytic acid content varies very greatly in different wheat products, ranging from 153.5 to 17299.0 μg/g. This article is protected by copyright. All rights reserved.

Differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) were used to examine the thermal decomposition of benzoyl peroxide (BPO). The interruption rescanning method was adopted to examine the effect of thermal history on the autocatalysis and thermal decomposition of BPO. Autocatalysis of BPO was verified through isothermal experiments. According to the DSC linear temperature rise data of BPO, mathematical methods were used to decouple and divide the peaks. Kinetic analysis using both the Kissinger and Friedman methods was performed. The initial decomposition temperature of the decoupled BPO ranged between 101.4 and 104.6 °C. The peak temperature was 110.9–126.2 °C, and the decomposition enthalpy was 229.7–524.2 J g–1. The apparent activation energy was higher in the coupling state than after decoupling one. The thermal history and isothermal experiments demonstrated that BPO possessed autocatalytic properties. Results revealed that initial decomposition temperature tended to decrease with the increase in interruption temperature. In addition, the apparent activation energy of BPO decreased following the thermal history analysis because of the formation of intermediate products from BPO in the thermal history experiments, which further promoted BPO’s thermal decomposition. This effect led to a decrease in BPO’s initial decomposition temperature.

Rationale Due to the ubiquity of fluorides and the small gap between a safe dose and a harmful one, it is necessary to develop a robust analytical method for determination of fluoride ions in various water samples with complex matrices. Methods Silylation of the fluoride ion was carried out by treatment with hydrochloric acid and phenyldimethylchlorosilane at room temperature. The formed phenyldimethylfluorosilane was detected by gas chromatography/mass spectrometry (GC/MS). Results Under the optimized conditions, linearity in the analytical method ranged from 0.050 to 5.0 μg/mL for the fluoride ion with R2 >0.9999. Reasonable reproducibility was obtained with the intraday relative standard deviation (RSD) (N = 5) of 2.04% and interday RSD (N = 5) of 3.75% at the concentration of 0.10 μg/mL. The developed method has been successfully applied to determine the fluoride ion in real water samples, including waste water samples, with the recovery between 81.12% and 113.04%. Conclusions A robust method for the determination of the fluoride ion has been developed by silylation with phenyldimethylchlorosilane and GC/MS analysis. The established method showed good anti-interference and precision, and it has been applied for determination of the fluoride ion in various water samples.

Thermal power generation based on coal-fired power plants has the advantages of stability and controllability and has been the largest source of electricity supply in China. Coal-fired power plants, however, are also accompanied by high carbon emissions and the release of harmful substances (mainly including sulfur dioxide, nitrogen oxides, and smoke dust), and are even regarded as the &ldquo, chief criminal&rdquo, in terms of air pollution. However, thermal power is also a pioneering industry involved in several environmental regulations and cleaner production techniques before other industries. Evidence of this is China&rsquo, s ultra-low emissions (ULE) policy on coal-fired power plants, implemented in 2015. To verify this policy&rsquo, s effect, this study treats ULE as an exogenous impact variable, examining its emissions reduction effect on SO2, NOx, and smoke dust in Eastern and Central China using the difference-in-difference method (DID). The results show that the total emissions of the three pollutants were abated by 0.133%, 0.057% and 0.036% in Eastern, and by 0.120%, 0.035% and 0.043% in Central China at every 1% rise of thermal power generated after ULE. In addition, several other factors can also argue for the promotion of thermal power. Other industries, such as steel or chemical, have proven that they can contribute significant SO2 and NOx emissions. Based on these results, we provide suggestions on synergistic emissions reduction among multiple industries, as well as a discussion on the necessity of implementing ULE in Western China.

To explore the effect of hydrogen bonding on organic semiconductors, four novel benzo[b]thiophene-benzo[b]furan analogues with contorted configuration were synthesized and exhibited good solubility in normal solvents. The optical, electrochemical characteristics and DFT simulated calculations demonstrates that the configuration feature of molecule plays an important role in modulating the π-conjugated delocalized degree. The X-ray crystallography further revealed the significant effect of hydrogen bonding on the planarity and aggregation mode of the molecular solid-state structure. The single-crystalline field effect transistor (FET) devices were fabricated and both compounds exhibit excellent FET performance with mobility over 0.8 cm2V−1s−1. All the results suggest that it would be an effective method to balance the solubility and electrical properties of organic π-conjugated compounds through regulating the molecular configuration by introduction of the hydrogen bonds.

RATIONALE Carcinogenic o-methylaniline is one of the banned aromatic amines in azo dyes, but it is very difficult to distinguish it from its noncarcinogenic isomers due to their identical retention time on chromatography and similar mass spectra. METHODS Imidization of the isomeric methylanilines was carried out by treatment with benzaldehyde under mild conditions. The formed derivatives were analyzed by gas chromatography/mass spectrometry (GC/MS). Theoretical calculations were carried out on the Gaussian 03 program by using the density functional theory method at the B3LYP/6-311+G(d,p) level. RESULTS Imidization of methylanilines occurred easily and gave rise to the corresponding N-methylbenzylidene benzenamines. The isomeric derivatives were completely separated by GC, and thus the three isomeric methylanilines could be determined simultaneously. Due to the ortho effect, the derivative from o-methylaniline has a characteristic fragment ion at m/z 118 with a stable bicyclic structure, and it could be easily differentiated from the meta- and para-isomers in electron ionization mass spectrometry. CONCLUSIONS These results provided a promising solution for simultaneous determination of isomeric methylanilines.

To explore how the different intermolecular non-covalent interactions synergistically affect the molecular packing and properties when they existed at the same molecules. A series of new pyrene derivatives with chalcogen atoms as bridges were designed and synthesized. The single crystal structures of the compounds revealed the significant effect of different intermolecular non-covalent interactions on the molecular packing. The thin film transistor devices were fabricated and exhibit high mobility over 0.04 cm2 V−1 s−1. The distinct difference of the OFETs performance suggests that the intermolecular non-covalent interactions have very important effect on gearing the molecular packing and properties.

In this paper, the notion of derivation on partially ordered sets is introduced and studied. Several characterization theorems on derivations are presented. The properties of the fixed points based on the derivations are investigated. Finally, the properties of ideals and operations related with derivations are studied.

Rationale m-Cresol is listed as a priority controlled contaminant in many countries, but it is very difficult to accurately determine isomeric cresols due to their incomplete chromatographic separation on commercially available chromatographic columns and their nearly identical mass spectra. Methods Silylation of isomeric cresols was carried out by treatment with N-methyl-N-(trimethylsilyl)trifluoroacetamide. The formed trimethyl(tolyloxy)silanes were analyzed by gas chromatography/mass spectrometry (GC/MS). Theoretical calculations were carried out with the Gaussian 03 program using the density functional theory (DFT) method at the B3LYP/6-311 + G(2d,p) level. Results The derivatives of three isomeric cresols and six isomeric xylenols have been completely separated on an HP-5MS capillary column within a GC run of only 10 minutes. In addition, the derivative o-cresol can be very easily differentiated from its isomers due to its characteristic base peak ion at m/z 91 in electron ionization (EI)-MS. DFT calculation results indicated that the formation of the abundant fragment ion at m/z 91 is attributed to a facile dissociation pathway involving the shift of a neighboring phenylmethyl hydrogen atom in EI-MS of trimethyl(o-tolyloxy)silane. Conclusions Silylation provides a promising solution for simultaneous determination of isomeric cresols and isomeric xylenols.

Al and F co-doped ZnO (FAZO) films with low doping ratios were deposited on glass substrates via radiofrequency magnetron sputtering. The effects of the sputtering power on the structural, morphological, electrical, and optical properties of the deposited films were systematically investigated. Good performance of the FAZO film, including a carrier concentration of 4.15 × 1020 cm−3, mobility of 37.35 cm2 V−1 s−1, resistivity of 4.03 × 10−4 Ω cm, and nearly 90 % average transmittance in the 400–1200 nm region, was obtained at 180 W. After annealing treatment, the photoelectric properties of the film were significantly improved, the mobility was enhanced to >50 cm2 V−1 s−1, the resistivity was reduced to ∼3.8 × 10−4 Ω cm, and the average transmittance between 400–1200 nm was increased to >91 %. The excellent electrical conductivity and wide-spectrum transparency indicated that the FAZO films have broad application prospects in wide-spectrum thin-film solar cells.

To track the illegal pangolin trade from Africa to Asia, we analyzed 1800 DNA samples from 30 seizures of African pangolin scales in Hong Kong during the period 2012–2016. We concluded that all four African pangolin species were present in trade, and that the white-bellied pangolin (Phataginus tricuspis) appeared most frequently (88.5%) in our samples. All six previously described phylogeographic lineages originating from the entire distribution range of P. tricuspis were found in the seizures, and the western central African lineage alone accounted for 67.1% of the samples of this species. Confirmed by modelling data, high DNA haplotype richness was present in most of the pangolin scale seizures, including those contained in small air parcels and large-volume sea shipments. Results suggest that African pangolins were hunted across large areas of their natural range and then delivered to a small number of trade transit hubs. Our study illustrates the utility of genetic analysis for characterizing the illegal pangolin trade and identifying the geographic origin of poaching hotspots.

For use as front electrodes in high-efficiency thin-film solar cells, ZnO transparent conductive films must have both broad spectral transmission and high conductivity. However, these characteristics are difficult to achieve simultaneously. In this work, F, Al, and Mg co-doped ZnO (FAMZO) films with superior electrical and optical properties were fabricated by RF magnetron sputtering and rapid thermal annealing (RTA). F and Al co-doping enables the film to maintain low resistivity and high transmittance in the visible and near-infrared regions, while Mg doping widens the optical band gap. Morphological characterization shows that the FAMZO films undergo recrystallization and growth during RTA, which further improves their electrical and optical properties. Our FAMZO films achieved a resistivity of 4.07 × 10−4 Ω cm, a mobility of 47.85 cm2/V, a carrier concentration of 3.21 × 1020 cm−3, and 90.54% average transmittance between 400 and 1400 nm. The excellent performance of our ZnO films makes them suitable for a broad range of applications in high-efficiency thin-film solar cells.

International audience; Despite being protected by both international and national regulations, pangolins are threatened by illegal trade. Here we report mitochondrial DNA identification and haplotype richness estimation, using 239 pangolin scale samples from two confiscations in Hong Kong. We found a total of 13 genetically distinct cytochrome c oxidase I (COI) haplotypes in two confiscations (13 and ten haplotypes respectively, with ten shared haplotypes between confiscations). These haplotypes clustered in two distinct clades with one clade representing the Sunda pangolin (Manis javanica). The other clade did not match with any known Asian pangolin sequences, and likely represented a cryptic pangolin lineage in Asia. By fitting sample coverage and rarefaction/regression models to our sample data, we predicted that the total number of COI haplotypes in two confiscations were 14.86 and 11.06 respectively, suggesting that our sampling caught the majority of haplotypes and that we had adequately characterized each confiscation. We detected substantial sequence divergence among the seized scales, likely evidencing that the Sunda pangolins were harvested over wide geographical areas across Southeast Asia. Our study illustrates the value of applying DNA forensics for illegal wildlife trade monitoring.

The inclusion complexes of four ligands binding to cyclodextrins (CDs) were studied by electrospray ionization mass spectrometry (ESI-MS) and the dissociation constants of the complexes were obtained. The 1:1 stoichiometric inclusion complex was found in the system of CD and fenbufen or aspirin. The obtained K D values of the inclusion complexes of fenbufen binding to α-CD and to β-CD are 4.38 × 10−4 mol L−1 and 2.12 × 10−4 mol L−1, respectively. The K D values of the inclusion complexes of α-CD-aspirin and β-CD-aspirin are 3.33 × 10−4 mol L−1 and 1.83 × 10−4 mol L−1, respectively. A non-linear least squares regression method was applied to validate the results which were consistent with each other. For the system of tetracycline hydrochloride and CD, the 1:1 and 1:2 stoichiometric inclusion complexes were found in the mass spectra. The K D,1 and K D,2 values of the 1:1 and 1:2 stoichiometric inclusion complexes of α-CD and tetracycline hydrochloride are 4.47 × 10−4 mol L−1 and 6.51 × 10−4 mol L−1, respectively, and those of β-CD and tetracycline hydrochloride are 2.26 × 10−4 mol L−1 and 8.57 × 10−4 mol L−1, respectively. For the system of norfloxacin and CD, besides the 1:1 and 1:2 inclusion complexes, the 1:3 stoichiometric inclusion complex was also found. The K D,1, K D,2 and K D,3 of α-CD and norfloxacin inclusion complexes are 4.61 × 10−4 mol L−1, 6.05 × 10−4 mol L−1 and 1.45 × 10−3 mol L−1, respectively. The three K D values of β-CD and norfloxacin are 1.96 × 10−4 mol L−1, 4.93 × 10−4 mol L−1 and 1.15 × 10−3 mol L−1, respectively.