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• The 1-mode and 0-mode transient voltage integrals are analyzed in the pure-fault network. • A single-end protection method using adaptive thresholds is proposed for the MMC-HVDC grid. • The proposed method is sensitive to single-pole high-resistance faults and suitableness for weak boundaries. For the bipolar modular multilevel converter-based high voltage DC (MMC-HVDC) grids, single-end protection methods suffer from low sensitivity in detecting high-resistance faults (HRF). The performance further deteriorates in a weak boundary configuration. To improve the deficiency, this paper proposes a protection method with adaptive thresholds. First, an MMC simplified circuit, an internal fault analysis network, and a DC bus fault analysis network are presented in pure-fault networks. The integral characteristics for 1-mode and 0-mode voltage fault components are studied under different locations. It is discovered that the relative size for two modal voltage integrals is different for internal faults and DC bus faults. A new form of mathematical morphology filter is proposed to select the required integral time. With 1-mode and 0-mode voltage integral, the fault identification method using adaptive threshold is proposed as well as its setting method. Simulations of a four-terminal MMC-HVDC system built in PSCAD/EMTDC verify the effectiveness of the proposed method. The method can fast detect internal single-pole HRFs of different locations and operate reliability under active power reversal, AC-side faults, and noise interference. Compared to some existing methods, the proposed method can detect high-resistance faults under weak boundary configurations. [ABSTRACT FROM AUTHOR]

Knowledge graph completion (KGC) aims to infer missing links between entities in knowledge graphs (KGs). Recently, models based on graph neural networks (GNNs) have gained widespread attention due to their effectiveness in leveraging the topological structure information of entities. Meanwhile, contrastive learning (CL) has been employed in GNNs-based models to provide more supervised signals for better entity representation in a self-supervised manner. However, existing methods overlook the potential global semantic collaboration among entities within the entire KG. And the application of CL in KGC models often adopt random graph augmentation or basic node structure contrast, leading to suboptimal performance. To tackle them, we propose a G lobal and L ocal S emantic- E nhanced C ontrastive Framework (GLSEC) for KGC. Specifically, we develop a global Attribute-aware encoder to capture the global semantic features of entities based on an entity-entity Attribute Interaction Graph (AIG). Additionally, we design a Light Graph Aggregation Network (Light-GAN) that innovatively updates the global semantic features using the AIG, combining both efficiency and a lightweight design. Furthermore, we introduce a Global-Local cross-view Contrastive Learning (GLCL) method that contrasts embeddings from global and local views, thereby improving contrastive sample quality and boosting the model's understanding of entities in various contexts. Extensive experiments show that our model outperforms state-of-the-art KGC methods on benchmark datasets FB15k-237 and WN18RR. • We consider both global attribute and local topology information of entities. • We construct a global attribute interaction graph based on entity attribute pairs. • We design a light graph aggregation network for efficient vector updates. • We develop a novel global-local cross-view contrastive learning method. [ABSTRACT FROM AUTHOR]

The snowline altitude at the end of melting season (SLA-EMS) provides a possibility to rapidly obtain a proxy for their equilibrium line altitude (ELA) which in turn is an indicator for the glacier mass balance. SLA-EMS is also an important parameter for the study of the relationships between climate and cryosphere. High Mountain Asia (HMA) hosts the largest glacier and perennial snow cover concentration outside the polar regions, but the spatial and temporal patterns of SLA-EMS are poorly understood. Here we investigate the spatial and temporal variation characteristics of SLA-EMS over the HMA on a grid-by-grid (30 km) basis, by using the cloud-removed MODIS fractional snow cover datasets from 2001 to 2016. The possible linkages between the SLA-EMS, temperature, precipitation and solar radiation changes over the HMA are also investigated. The results are as follows: (1) the proposed MODIS-based grids (30 km) SLA-EMS extracting method is efficient in monitoring the spatiotemporal patterns of the SLA-EMS for a large-scale area. (2) In the HMA, the spatial change of the SLA-EMS (from 3114 to 6907 m) exhibits a large spatial heterogeneity. The SLA-EMS decreases from the high altitude region of Himalayas and inner Tibet to surrounding low mountainous area. (3) The SLA-EMS of HMA generally shows a rising trend in the recent years (2001–2016). In total, 82.35% (26.32% with a significant increase) and 17.65% (0.74% with a significant decrease) of the study area show increasing and decreasing trends in SLA-EMS, respectively. The SLA-EMS significantly increases in east Tien Shan (5.16 m yr−1), west Tien Shan (4.64 m yr−1), Inner Tibet (3.64 m yr−1), south and east Tibet (9.18 m yr−1), east Himalaya (8.52 m yr−1) and Hengduan Shan (7.48 m yr−1). (4) The summer temperature trends to be the dominant climatic factor affecting the variations of SLA-EMS over the HMA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Influence of MILs on LRC surface wettability was analyzed. • Mechanism of coal wettability modification was explained from adsorption. • Propose salting out the separation-strong magnetic recovery process and key parameters. Three types of magnetic ionic liquids (MIL) ([C 12 mim]FeCl 4 , [C 12 mim] 2 CoCl 4 , and [C 12 mim] 2 NiCl 4) were chosen to study the enhancement of the quality and utilization of low-rank coal (LRC). The mechanism of coal wettability modification was explained from the macrocosm and microcosm points of view by contact angle, adhesion work, and adsorption studies, and the recovery of MIL was realized by salting out the separation-strong magnetic recovery (SMR). The contact angle and adhesion work results showed that [C 12 mim]FeCl 4 had the greatest effect on coal wettability. The adsorption on the LRC surface was as follows: [C 12 mim]FeCl 4 > [C 12 mim] 2 CoCl 4 > [C 12 mim] 2 NiCl 4. The adsorption thermodynamics indicated that MIL conformed to the Langmuir isotherm model, which is a spontaneous reaction of exothermic entropy minus physical adsorption. The adsorption kinetic process belong to the pseudo-second-order kinetic model and was influenced by the combined action of intraparticle and liquid film diffusion. From the contact angles and adsorption thermodynamics, it can be inferred that [C 12 mim]FeCl 4 has the highest activity and can better adsorb onto the LRC surface, covering the oxygen-containing functional groups and reducing the wettability to achieve efficient quality improvement and utilization of LRC. Through the research of salting-out separation-SMR, the most suitable salting-out reagent was found to be NaCl, and the highest recovery was obtained when the concentration reached the solubility level. As the magnetic field strength increases, the recovery rate gradually increases. The recovery of [C 12 mim]FeCl 4 was more than 90% when it reaches 1.5 T, and it could be recovered by magnetic separation. [ABSTRACT FROM AUTHOR]

Highlights • An approach to estimate the probability distribution of electrified railway traction loads using a non-parametric method. • This method accounts for both optimal bandwidth selection and boundary bias. • This method obtains more accurate results compared with parametric methods and traditional Gaussian kernel density estimator. Abstract The probabilistic modeling for traction load is one of the most basic and challenging work in the field of electrified railway. The improved diffusion-based kernel density estimator (DKDE) is used for the first time to establish the probability distribution of traction loads. Based on the diffusion partial differential equation of finite domain, DKDE can be obtained by discrete and inverse discrete cosine transform. The DKDE effectively accounts for both the optimal bandwidth selection and boundary correction. Based on the measured data (feeder currents and re/active power), four goodness-of-fit tests are applied to test the estimated probability distribution of traction loads. Compared with the parametric estimation models and Gaussian kernel density estimator (GKDE) respectively, the results show that this probability distribution of traction loads by DKDE is more accurate and suitable. Moreover, this DKDE has strong applicability and versatility for the random variation of different traction loads. [ABSTRACT FROM AUTHOR]

• The reactor line-mode transient voltage fault component in dc grid is analyzed. • The mathematical morphology-based method to select the partition time for two parts is proposed. • The protection scheme using the ratio of the two-part voltage integral is proposed. • The high sensitivity to high impedance faults is validated in a four-terminal meshed DC grid. The fast, sensitive, and reliable primary protection method can ensure the continuous and reliable operation of the modular multilevel converter (MMC)–based HVDC grid during dc faults. This paper proposes a fault detection method based on the ratio of voltage integrals to improve the single-end method sensitivity to high-resistance faults. First, the reactor line-mode transient voltage caused by the initial traveling wave (TW) is analyzed in the fault component network. The exponential term of the voltage is independent of the fault resistance and can be reflected by the proposed voltage integral ratio. Next, the influence of subsequent TWs on the integral is analyzed. The partition time, selected by the mathematical morphology, is proposed to divide the voltage sampling data into two parts. Finally, the criterion using the ratio of the two-part voltage integral is proposed to detect internal faults. The ± 500 kV bipolar MMC-HVDC grid built on PSCAD/EMTDC validates that the proposed method can fast identify internal faults, and the protected zone covers the whole line length. Smulation cases analyze the influence of the reactor and sampling frequencies on the proposed method. Moreover, the method is sensitive to high-resistance faults and can work under white noise and different wiring modes. [ABSTRACT FROM AUTHOR]

Arsenic element refines W powders significantly during the hydrogen reduction process of tungsten oxide in our previous studies. In this paper, the nanocrystalline WC-As composite powders were prepared by carbonization of nano W-As composite powders and the effects of arsenic on the growth of WC powder were discussed in detail. The prepared samples were characterized by X-ray diffraction, differential scanning calorimetric analysis, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy and Inductively Coupled Plasma. The results showed that arsenic appropriately raised the initial temperature of carbonization, significantly accelerated carbonization reaction process and shorten the reaction time. Moreover, WC-As composite powders merged and grew up directly without particle expansion and cracking. And the nano WAs 2 particles attached to WC grain boundaries and hindered the growth of WC grain through grain boundary migration. The above two effects resulted in the WC-As composite powders prepared at 1300 °C for 2 h with the average size of about 121 nm in diameter. [ABSTRACT FROM AUTHOR]

[Display omitted] • Potassium salt has an interactive effect on the organic components of pyrolysis products. • Both potassium ions and acid ions can affect the pyrolysis products. • K 2 CO 3 has the strongest catalytic effect and its demethylation ability reaches about 57.00%. • KCl produces the highest proportion of guaiacol. • CH 3 COOK promoted the formation of acids in the product and had better fusion effect with bio-chars. There have been few investigations on the pyrolysis characteristics of furfural residue lignin in general. The effects of reaction temperature and potassium salt on the pyrolysis products of furfural residue alkali lignin were explored as a result. The char yield reduced as the pyrolysis temperature increased, whereas the gas yield increased. At 500 °C, the highest bio-oil yield was 20.88 %. The three additives then had a pattern of increasing char and gas yield while decreasing bio-oil yield. K 2 CO 3 was shown to be the greatest representation of the influence of potassium salt, with a demethylation ability that was 57.00 % greater than the other two additives. Potassium chloride, on the other hand, caused alkali lignin to create a larger amount of guaiacol. In biochar, CH 3 COOK had a good fusion effect. The effect of potassium salt additions on solid products was primarily to accelerate the condensation and cyclization of the benzene ring in char, hence increasing char yield, with little influence on gas. The cogeneration effect of various potassium salt additives on pyrolysis products was investigated, and a potential catalytic mechanism was proposed, providing a useful theoretical foundation for the high-value exploitation of furfural waste. [ABSTRACT FROM AUTHOR]

With the increased penetration of wind power into the electric grid of China, many challenges emerge due to its fluctuation and intermittence. In this context, it is crucial to achieve higher accuracy of the short-term wind power forecasting for safe and economical operation of the power system. Hence, this paper proposes a novel hybrid methodology for short-term wind power forecasting, successfully combining three individual forecasting models using the adaptive neuro-fuzzy inference system (ANFIS). The backpropagation neural network (BPNN), radial basis function neural network (RBFNN), and least squares support vector machine (LSSVM) are selected as the individual forecasting models. A new data preprocessing method based on Pearson correlation coefficient (PCC) is also applied for selecting proper inputs for three individual models. Results obtained show the advancement of the PCC based data preprocessing method. Also, the comparison studies demonstrate that the proposed hybrid methodology presents a significant improvement in accuracy with respect to three individual models. [ABSTRACT FROM AUTHOR]

• A quantitative calculation and analysis method of the correlation degree between traction load sequences based on the optimal delay is proposed. • The generalized EM algorithm combined with the normalized root mean square error (NRMSE) is proposed to solve the optimal delay model. • Considering the effects of no-load removal processing, inverse transformation, and different sampling intervals, the maximum correlation coefficient of Pearson, Spearman and Kendall and the corresponding optimal delay amount are obtained. • The proposed method provides the basic information of correlation for traction load modeling and its application. The correlation between traction load sequences is an important basic information for traction load modeling, but the correlation and time difference between traction load sequences restrict each other. The analysis method for the correlation between traction load sequences based on the optimal delay method is proposed in this paper. This method appropriately delays the sequences between different traction loads and taps the indirect correlation between traction load sequences. Firstly, the maximum correlation coefficient between the two traction load sequences after delaying is taken as the objective function to establish the optimal delay model. The delay time range and the monotonicity of sequence occurrence time constitute the constraints. Secondly, combined with the normalized root mean square error (NRMSE) index, the generalized expectation maximization (EM) algorithm is proposed to solve the optimal delay model. Finally, the traction load sequence with one and two trains at any period of time from the four traction substations of high-speed railway are taken as case examples. Considering the effects of no-load removal processing, inverse transformation, and different test intervals, the maximum correlation coefficients of Pearson, Spearman and Kendall, as well as the corresponding optimal delay amount are calculated. The analysis results show that the proposed method in this paper can dig out the potential delay correlation between traction load sequences, as well as provide basic reference information for traction load modeling and its application. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Ibrahim time domain (ITD) method is able to identify the frequencies, damping and mode shapes of the interarea modes. [•] A zero-phase low-pass filter will greatly improve the performance of the ITD method in the presence of measurement noise. [•] The ITD method is much faster than the stochastic subspace identification (SSI) method in estimating interarea modes. [•] When the input ring-downs are contaminated by ambient noise, the ITD method performs better than the SSI method. [•] The ITD method may still give quite acceptable estimation results when only limited input signals are available. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, the interaction of vanillin and human serum albumin (HSA) has been characterised by molecular modelling, fluorescence, Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopic methods. The results of molecular modelling suggested that vanillin was located within the binding pocket of subdomain IIA of HSA mainly by hydrophobic forces. The quenching of HSA fluorescence takes place with a binding constant (K) of 8.8, 7.7, 5.7, 4.2×104 M−1 at four different temperatures (288, 298, 308, 318K), respectively. Meanwhile, the number of binding site (n ≈1) was also obtained from fluorescence titration data. The enthalpy change ΔH 0 and the entropy change ΔS 0 were calculated to be −20kJmol−1 and 5.8Jmol−1 K−1 according to the Van’t Hoff equation. Furthermore, the alterations of protein secondary structure in the presence of vanillin were explored by FT-IR and CD spectra. [Copyright &y& Elsevier]

Abstract: In this study, the interaction of the endocrine disruptor bisphenol A (BPA) and human serum albumin (HSA) was investigated by molecular modelling, fluorescence, ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR) and circular dichroism spectroscopy (CD). The association constants between BPA and HSA were determined using the Scatchard equation. The thermodynamic parameters of the binding reaction (ΔG 0, ΔH 0 and ΔS 0) were measured, and they indicated the presence of hydrophobic forces in the BPA–HSA interaction, which agreed well with the results from molecular modelling. The alterations of protein secondary structure in the presence of BPA were confirmed by UV–vis, FT-IR and CD spectroscopy. Lastly, the average binding distance, r, between BPA and HSA was evaluated and found to be 1.82nm according to Förster’s theory of non-radiation energy transfer. [ABSTRACT FROM AUTHOR]

• A new pair of estimate points with only first three-order moments are added for additional calculation to improve the calculation accuracy of 3PEM. • It avoids the calculation of higher order center moments and the non-real number solutions that may occur with normalized center distances. • Taking into account the different coefficients of variation and the results of MCS method as a reference, the results have been compared with those obtained by the existing 2PEM and 3PEM in the presence of Normal distribution inputs, correlated inputs and non-normal inputs. • The performance and applicability to system size of the improved three point-estimate method scheme are discussed and compared. An improved three point-estimate method (I3PEM) scheme is proposed to estimate the probability moments of probabilistic power flow (PLF) in this paper. I3PEM is obtained by the existing three point-estimate method (3PEM), two point-estimate method (2PEM) and Chebyshev inequality. With only first three order moments (mean, standard deviation and skewness) of input random variables, the additional calculations in I3PEM are performed by a newly added pair of estimate points to improve the accuracy of estimated moments for output random variables. It is avoided the calculation of higher order center moments and the non-real number solutions that may occur with normalized center distances. The case studies of IEEE 14-bus and 118-bus system are employed to verify the performance of I3PEM in the presence of Normal distribution inputs, correlated inputs and non-normal inputs. Under the different coefficient of variation (CV) conditions, the results of MCS are used as benchmark. The accuracy of results obtained by I3PEM have been validated by comparing with those obtained from the basic 3PEM and 2PEM. Further, the advantages and applicability of I3PEM are compared. [ABSTRACT FROM AUTHOR]

In recent years, few-shot knowledge graph completion (FKGC) has gained popularity as a solution to the long-tail distribution problem of real-world knowledge graphs (KGs). The previous knowledge graph completion (KGC) models obtain triple representation merely relying on the structure view, ignoring the valuable semantic knowledge. In this paper, we propose a multi-view framework for few-shot relation learning to address the issue. Specifically, based the structural information of the graph obtained using the structure view, we add the text view and the commonsense view. The text view employs text descriptions of entities and relations to obtain a richer semantic representation. The commonsense view performs high-quality negative sampling based on complex relations. Moreover, commonsense semantic constraints are invoked to suppress the overfitting caused by the complexity of the relation matrix. Extensive experiments show that our model outperforms state-of-the-art FKGC methods on the frequently-used benchmark datasets FB15k237-One and NELL-One. • We design a multi-view joint encoder to learn semantic information. • Commonsense semantic constraints are introduced to explore semantic relations. • We leverage the commonsense view to generate high-quality negative triples. • We identify candidate entities that match commonsense in the prediction process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Use quantum chemistry predict MIL structure and properties. • MIL break hydrogen bond in coal and cause coal swelling by simulation methods. • Pretreatment of coal reduces the loss of weight temperature and improves tar yield. Since direct combustion of low-rank coal is inefficient, expansion and dissolution are essential for better use of coal as an energy source. In this study, [C 8 mim]FeCl 4 molecular configuration was synthesized by quantum chemical simulation method, and Magnetic ionic liquid (MIL) was used to modify coal to improve its swelling efficiency. The FT-IR and Raman properties of MIL were measured by simulation combined with practical methods. Dmol3 was used to study the hydrogen bond changes of coal molecules induced by MIL. When MIL interacts violently with organic matter in coal, the cross-linking network structure generated by non-covalent bonds is destroyed, resulting in the break of covalent bonds such as hydrogen bonds. Further experimental study shows that the pore structure and surface morphology of modified coal samples will be damaged, indicating that the MIL has the ability to dissolve hydrogen bonds and pretreat low-rank coal. It was found by TGA that MIL treatment can increase the tar yield of coal by up to 4.79% and reduce ash content by 3.51%. Through the integration of molecular modeling and experimental analysis, this study elucidates the fundamental principles underlying MIL pretreatment of coal, thereby providing a viable strategy for efficient quality improvement utilization of low-rank coal. [ABSTRACT FROM AUTHOR]

• The time sequence probabilistic model of traction station load of high-speed railway considering the spatial correlation is proposed by applying the diffusion-based kernel density estimator (DKDE). • The model of time sequence three-phase probabilistic power flow (3PPF) calculation for power system connected with traction load is proposed through the port transformation of traction power supply system (TPSS). • The algorithm of time sequence 3PPF calculation model based on the three-point estimation method (3PEM) owned both the accuracy and the computational efficiency. • The time sequence probability density curves of voltage amplitude and three phase voltage unbalance degree of grid are obtained under the impact of the asymmetry and spatiotemporal of traction load of high-speed railway. The increasing traction station load of high-speed railway with single-phase, high-power, spatiotemporal mobility, and uncertainty has brought major impacts and challenges to the power system. The non-negligible characteristics are the spatial distribution of traction stations on high-speed railway lines, the time sequence of traction load moving with EMUs, as well as the nonparametric probabilistic features and correlation of traction load. A method of time sequence three-phase probabilistic power flow (3PPF) calculation for power system including traction station load of high-speed railway is proposed in this paper. Firstly, through the port transformation of traction power supply system (TPSS), the three-phase equivalent model of TPSS is established to construct an unbalanced three-phase power flow calculation model of grid with traction station load. Secondly, considering the spatial correlation, time sequence and non-parametric probabilistic feature of traction load, the time sequence probabilistic models of multiple traction station loads are built based on diffusion-based kernel density estimator (DKDE). Then, the algorithm of time sequence 3PPF calculation based on three-point estimation method (3PEM) is applied to deal with the computational efficiency and accuracy problems of 3PPF considering correlation and timing. Finally, the two modified three-phase power systems are employed for case studies in combination with the measured data of traction station of a high-speed railway. The validity and computing efficiency of the proposed method are verified. [ABSTRACT FROM AUTHOR]

Two novel Bacillus glycoside hydrolase family 53 (GH53) endo-1,4-β-galactanases (Bs936 and Bs4828) were identified. The recombinant Bs936 and Bs4828 displayed maximal activities at pH 5.5/55 °C and pH 6.5/65 °C, respectively. Stability analyses revealed that the enzymes were stable between pH 4.5–10, retaining over 80% activities after 12 h incubation at 25 °C. Moreover, Bs936 maintained about 75% activity after being treated at 45 °C for 2 h, while Bs4828 kept full activity after 4 h of incubation at 50 °C. Importantly, Bs936 and Bs4828 exhibited good activity towards β-1,4-galactan, showing specific activities of 1859.46- and 3110.79 U/mg towards potato galactan, respectively. The corresponding K m and k cat /K m were 4.93 mg/mL and 296.35 mL/mg/s for Bs936, and 6.60 mg/mL and 707.12 mL/mg/s for Bs4828. Extensive synergy assays revealed that each endo-1,4-β-galactanase acted synergistically with the other β-galactosidase (Bs937 or Bs4829), endo-1,5-α-L-arabinosidase (BsAbn2) and an endoxylanase/endoglucanase+cellulase mixture (BaXynA + LsCel) towards the hydrolysis of galactan, debranched arabinan/arabinan, and pretreated corn stover, respectively. The corresponding degrees of synergy were 1.28, 1.17/1.09, and 1.15 for Bs486 and 1.55, 1.04/1.08, and 1.11 for Bs4828, respectively. This study expands the repertoire of GH53 enzymes, and demonstrates the role of two highly active endo-1,4-β-galactanases in polysaccharides hydrolysis. [ABSTRACT FROM AUTHOR]

An accurate awareness of the properties of the interarea electromechanical oscillation modes is essential for the secure operation of the power systems. Previously, the Ibrahim time domain (ITD) method has been applied to estimate the interarea oscillation modes using ring-down signals caused by major disturbances (such as three phase faults). In this paper, through the combination of the random decrement technique (RDT) and the ITD method, the RDT–ITD method is proposed to estimate the interarea modes during ambient operation of the power systems, using random responses caused by random changes of the loads. The estimated parameters include the frequencies, damping ratios and mode shapes. Considering the fact that both the ambient excitations and the measurement noise are stochastic in nature, Monte Carlo simulations were conducted to evaluate the performances of the RDT–ITD method in a statistical way. Simulation results in the 16 machine nonlinear power system model, as well as comparison results with the RDT-Prony method, the NExT-ERA method and the Subspace method realized by N4SID (Numerical algorithm for Subspace State Space System Identification) show that the RDT–ITD method is promising in estimating the interarea modes during ambient operation conditions. The RDT–ITD method was also validated using real PMU measurements from Sichuan power grid of China. [ABSTRACT FROM AUTHOR]

Abstract: Undoped TiO2 exhibited deterioration in microwave (MW) dielectric loss as it reached its maximum density due to the reduction of Ti4+ to Ti3+ causing oxygen vacancies at high sintering temperatures. By adding small amounts of acceptor dopants with ionic radii between 0.5 and 0.95Å, reduction during sintering was suppressed. The upper limit of ionic radius was discrete with almost no observed effect using dopants >0.96Å ionic radius. In addition, the microwave dielectric loss of undoped TiO2 could be improved by annealing at 1500°C for 10h in air, presumably as a result of re-oxidation. High loss samples exhibited a dark ‘core’ to the naked eye which was absent in low loss ceramics. Transmission electron microscopy revealed that grains in the dark core contained planar defects attributed to the condensation of O vacancies onto specific crystallographic planes, in a manner similar to that observed in Magnelli phases. [Copyright &y& Elsevier]

Abstract: Dissolved organic matter (DOM) is a complex and poorly understood mixture of natural polymeric organic material, and plays an important role in material transport and carbon balance in aquatic ecosystems. Fluorescent dissolved organic matter (FDOM) represents a major portion of the total DOM and has often been used as a tracer to identify the source or track the movement of DOM in aquatic environment. In this work, we have applied Excitation/Emission Matrix spectroscopy (EEMs) to study the distribution and characteristics of FDOM in seawater of Bohai Sea in Northern China. Hierarchical Cluster method has been used to assess the similarities and dissimilarities of the entire EEMs data sets of seawater samples collected from different regions of the Bohai Sea. The distribution of different seawater samples as revealed by multivariate results has been used to track the movement of DOM material in the Bay, and the results from such analysis are in good agreement with those obtained from seawater circulation and dynamics models. [Copyright &y& Elsevier]

Abstract: Camellia oil is often the target for adulteration or mislabeling in China because of it is a high priced product with high nutritional and medical values. In this study, the use of attenuated total reflectance infrared spectroscopy (MIR-ATR) and fiber optic diffuse reflectance near infrared spectroscopy (FODR-NIR) as rapid and cost-efficient classification and quantification techniques for the authentication of camellia oils have been preliminarily investigated. MIR spectra in the range of 4000–650cm−1 and NIR spectra in the range of 10,000–4000cm−1 were recorded for pure camellia oils and camellia oil samples adulterated with varying concentrations of soybean oil (5–25% adulterations in the weight of camellia oil). Identifications is successfully made base on the slightly difference in raw spectra in the MIR ranges of 1132–885cm−1 and NIR ranges of 6200–5400cm−1 between the pure camellia oil and those adulterated with soybean oil with soft independent modeling of class analogy (SIMCA) pattern recognition technique. Such differences reflect the compositional difference between the two oils with oleic acid being the main ingredient in camellia oil and linoleic acid in the soybean oil. Furthermore, a partial least squares (PLS) model was established to predict the concentration of the adulterant. Models constructed using first derivative by combination of standard normal variate (SNV), variance scaling (VS), mean centering (MC) and Norris derivative (ND) smoothing pretreatments yielded the best prediction results With MIR techniques. The R value for PLS model is 0.994.The root mean standard error of the calibration set (RMSEC) is 0.645, the root mean standard error of prediction set (RMSEP) and the root mean standard error of cross validation (RMSECV) are 0.667 and 0.85, respectively. While with NIR techniques, NIR data without derivative gave the best quantification results. The R value for NIR PLS model is 0.992. The RMSEC, RMSEP and RMSECV are 0.70, 1.78 and 1.79, respectively. Overall, either of the spectral method is easy to perform and expedient, avoiding problems associated with sample handling and pretreatment than the conventional technique. [Copyright &y& Elsevier]

Abstract: High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been applied to isolate and purify bioactive flavone compounds from the ethanol extract of Glycyrrhiza inflata Bat., a particular plant species of licorice. HSCCC separation was performed with a two-phase solvent system composed of n-hexane–chloroform–methanol–water (5:6:3:2, v/v) by eluting the lower mobile phase at a flow rate of 1.8ml/min and a revolution speed of 800rpm. Purification was performed with a two-phase solvent system composed of n-hexane–chloroform–methanol–water (1.5:6:3:2, v/v) by eluting the lower mobile phase at a flow-rate of 1.5ml/min and a revolution speed of 800rpm. Two major flavone peaks: inflacoumarin A and licochalcone A were collected and the respective yields of the peaks amount to 6mg (8.6%, w/w) and 8mg (11.4%, w/w) from 70mg of the crude extract sample. The purities of inflacoumarin A and licochalcone A reached 99.6% and 99.1%, respectively, after a sequential purification run. The structures of inflacoumarin A and licochalcone A were positively confirmed by 1H NMR and 13C NMR, 1H–13C-COSY, UV, FT-IR and electron ionization MS analyses. [Copyright &y& Elsevier]

In this study, novel multicore-shell ZnO microspheres were synthesized via a simple solvothermal method based on the coordination of salicylic acid under the protection of polyvinylpyrrolidone (PVP). In this process, as an organic acid, salicylic acid with a benzene ring structure rich in hydroxyl and carboxyl functional groups can not only play a structure-oriented role, but also can etch materials to form a hollow structure. Compared with traditional basic synthesis methods, the diversity of coordination forms makes the structure more abundant. The multicore-shell ZnO was annealed at 450, 600, and 750 °C respectively. Under the driving force of reducing the surface free energy, part of the multi-nucleus inside the microspheres aggregated to form large particles, and the other part adhered to the shell layer to grow. The crystallinity, morphology and surface composition of the ZnO microspheres were characterized by XRD, SEM, TEM, XPS, BET and FT-IR analyses. The multicore-shell ZnO-based sensor that exhibited excellent sensitivity to acetone (2 ppm, S Ra/Rg = 8.6) at an optimal working temperature of 240 °C, with a low limit of detection of 100 ppb with a S Ra/Rg = 2.9. The annealed ZnO-based sensors also performed well, among them, the product annealed at 750 °C (ZnO-750) is the best, with a response of 6.4 to 2 ppm acetone. The sensors exhibited satisfactory selectivity and can detect acetone in the presence of other interfering gases, including NO, CO, NH 3 , HCHO, CH 3 OH and C 2 H 5 OH. The outstanding sensitivity of the multicore-shell ZnO sensor to acetone can be attributed to its large specific surface area and pore volume, which favors gas adsorption, penetration and diffusion. For the annealed ZnO, we speculated that the specific exposed crystal plane (002) plays a decisive role in the good adsorption and reaction of acetone. [ABSTRACT FROM AUTHOR]

As an opportunistic causative pathogen of "Visceral White Spot Disease" in several kinds of teleost, Pseudomonas plecoglossicida has caused huge economic losses to aquaculture. Flagella is the motility organ of bacteria as well as a vital virulence factor. The protein encoded by the fliP gene is involved in the formation of the flagellar type III secretion export apparatus, which plays a crucial role in flagellar assembly. In this study, the Δ fliP and C-Δ fliP strains of P. plecoglossicida were constructed to explore the biological profiles mediated by the fliP gene and its effects on the virulence of this organism. Compared to the wild type strain (NZBD9) of P. plecoglossicida , the deletion strain Δ fliP exhibited a significant impairment in swimming motility, chemotaxis, adhesion, and biofilm formation abilities. The transcriptomic analysis of the NZBD9, Δ fliP and C-Δ fliP strains revealed that the fliP gene may affect the biological profiles of P. plecoglossicida by down-regulating the expression of flagellar assembly, type 6 secretion system and bacterial chemotaxis related genes. Furthermore, the results of artificial infection showed that the virulence of Δ fliP strain to hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) was attenuated, with a LD 50 value of 2.5 × 104 CFU/fish. These findings demonstrate that the fliP gene contributes to the virulence of P. plecoglossicida by regulating its motility. • Δ fliP strain was constructed by a two-step allelic exchange from P. plecogerossicida NZBD9 strain. • Deletion of fliP significantly reduced pathogenicity of P. plecoglossicida to hybrid grouper. • Δ fliP exhibited a significant impairment in swimming motility, chemotaxis, adhesion, and biofilm formation abilities. • Δ fliP down-regulated the expression of flagellar assembly, type 6 secretion system and bacterial chemotaxis related genes. [ABSTRACT FROM AUTHOR]

• PtCo nanocrosses (PtCo CNCs) with concave structure were easily synthesized. • Iminodiacetic acid plays a key role in regulating the concave cross-like structure. • Concave cross-like structure can provide more under-coordinated atoms as active sites. • PtCo CNCs shows great enhanced MOR performance than commercial Pt/C. Concave nanostructures with the high-index facets and highly exposed active sites are desirable in energy conversion technology, whereas the current synthetic strategies still remain challenging. Herein, we report a facile and effective strategy for the synthesis of concave PtCo nanocrosses (PtCo CNCs) with the assist of iminodiacetic acid (IDA). Owing to strong chelation of IDA with metal ions through carboxyl and imino groups, the IDA molecule plays a key role as the structure-directing agent in regulating the cross-like structure. The as-prepared PtCo CNCs are constructed by six arms in three-dimensional space and each protruding arm has concave surface bounded by high-index facets. As an electrocatalyst towards methanol oxidation reaction (MOR), the developed PtCo CNCs exhibit much enhanced specific and mass activity of 3.04 mA cm Pt −2 and 692 mA mg Pt −1 that are 3.1 and 2.6 times greater than those of commercial Pt black, respectively. The excellent electrocatalytic stability and improved tolerance toward CO ads are also demonstrated on PtCo CNCs catalyst. The remarkable electrocatalytic performance of PtCo CNCs towards MOR is highly related with their concave surface and high-index facets, as well as synergistic effect between Pt and Co atoms. The facile synthetic strategy and outstanding MOR performance endow PtCo CNCs with great application potential in fuel cells as an anode catalyst. [ABSTRACT FROM AUTHOR]

Effect of calcium on tungsten oxide, tungsten, tungsten carbide and WC-Co cemented carbides, and the evolution of Ca during the preparation of cemented carbides were investigated studied by the liquid-solid doping method. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to analyze the phase compositions, particle sizes and morphologies of them, respectively. The results showed that 1% Ca-doped tungsten oxide consisted of WO 3 and CaWO 4 phases. After hydrogen reduction, the size of Ca-doped tungsten decreased slightly. During carbonization, most of the CaWO 4 and Ca 4.26 W 10 O 30 transformed to CaC 2 . After that, the majority rest of the CaWO 4 and Ca 4.26 W 10 O 30 both reduced to CaO in the sintering process. The microhardness, flexural strength and fracture toughness of 1%Ca-doped WC-6wt.%Co cemented carbide were 14.83 GPa, 1456 MPa and 9.98 MPa m 1/2 , decrement of 10.12%, 29.53%, and 10.57%, respectively. A refining mechanism for tungsten and a weakening mechanism for WC-Co cemented carbides were proposed. [ABSTRACT FROM AUTHOR]

A surface-enhanced Raman scattering (SERS) sensor based on the folding and assembly characteristics of the three-dimensional structure of paper fibers, the skeleton controllability of metal-organic framework materials (MOFs), and the morphology designability of plasmonic noble metal materials has been established for rapid on-site determination of ethephon in food. HKUST-1(Cu) was assembled onto a carbon-treated chromatographic paper matrix by electrodeposition, and its skeleton respiration and sponge effect were used to overcome the bottleneck problem of poor affinity of SERS substrate for target molecules. Further coupled with the targeted recognition specificity of biomimetic antibodies, a paper-based interface with high specificity of molecular sensitivity was constructed. A sandwich multi-stage progressive enhancement structure was designed to couple plasma pine branch-shaped silver material in situ at the interface to realize superposition and collaborative amplification of SERS signals. When the paper-based strip sensor was used to monitor ethephon, it demonstrated a linear range of 10−3 to 10 mg kg−1 and a detection limit of around 1.39 × 10−4 mg kg−1. The construction and application of the paper-based HKUST-1(Cu)/biomimetic antibodies/pine branch-shaped silver material sensor will provide technical means and theoretical support for the rapid and efficient identification of biological ripening agent residues in food with multi-level signal enhancement. [Display omitted] • A three-dimensional SERS sensor was developed for the detection of plant growth regulator residues. • Innovative preparation of three-dimensional polyhedral metal-organic frame materials. • A reusable SERS paper scrip which with multiple signal amplification strategies. [ABSTRACT FROM AUTHOR]

For the first time, the composition, concentration and distribution characteristics of typical lipophilic marine algal toxins (LMATs) are investigated in surface seawater, suspended particulate matter (SPM) and sediments from the Yellow Sea and the Bohai Sea, China. Pectenotoxin-2 (PTX2) and okadaic acid (OA) were detected in offshore surface seawater samples ( n = 67) of the Yellow and Bohai Seas, and PTX2 was found in higher concentrations than OA. The concentrations of PTX2 were between 0.49 and 14.14 ng/L. OA, dinophysistoxin-1(DTX1), PTX2 and gymnodimine (GYM) were detected in the nearshore surface seawater samples ( n = 20) of the Haizhou Bay of the Yellow Sea. OA concentrations were between 11.47 and 55.85 ng/L. There was a large degree of variation in the concentrations of DTX1, from < limit of quantification (LOQ) up to 143.14 ng/L. The nearshore surface seawater samples ( n = 13) obtained from the Longdao area of the Bohai Sea mainly contain OA (5.00–24.14 ng/L) and DTX1 (1.52–49.39 ng/L), with PTX2 concentrations being less than the LOQ. Several LMATs were also detected both in the SPM and sediment samples of each study area. In summary, the LMAT composition and concentration levels in the surface seawater found in nearshore samples were substantially different from those of samples from the distant shore, which indicated the obvious regional characteristics of LMATs according to their spatial distribution in the Yellow Sea and the Bohai Sea. [ABSTRACT FROM AUTHOR]

This study aimed to develop an exact mass suspect screening approach to perform finding of multiple lipophilic marine toxins (LMTs) in seawater, suspended particulate matter (SPM), and marine sediment from marine aquaculture area using liquid chromatography-time of flight mass spectrometry (LC-TOF/MS). The method was validated and proven to be reliable for the screening of various LMTs. Then, the method was applied to screen LMTs in marine environmental samples collected from mariculture area of Jiaozhou Bay, China. Okadaic acid (OA), pectenotoxin 2 (PTX2), etc were detected and tentatively identified. Positive detection results were confirmed by liquid chromatography-tandem mass spectrometry (LC–MS/MS), and contents of OA and PTX2 in seawater, SPM and marine sediment were also quantified. The mean concentration of OA ranged from 2.71 to 14.06 ng L −1 in seawater and from 0.78 to 3.34 ng g −1 dry weight in marine sediment. The mean concentration of PTX2 ranged from 0.86 to 7.90 ng L −1 in seawater, from 1.56 to 10.67 ng in SPM obtained from 1 L seawater sample and from 0.95 to 2.23 ng g −1 dry weight in marine sediment. The above results suggested that the proposed method was convenient and reliable for the screening of LMTs in different marine environmental samples. In addition, typical LMTs exist in different marine environmental media of the mariculture area of Jiaozhou Bay, China. Follow-up studies should focus on improving current understanding on the environmental behavior of these LMTs in the marine aquaculture environment. [ABSTRACT FROM AUTHOR]

The presence of toxins in harmful algal blooms (HABs) poses considerable concerns because of their potential adverse effects on ecological environments and human health. When marine HABs occur, efficient screening and identification of toxins in different kinds of HAB algae remains a challenge. In this study, the applicability of serial coupling of reversed-phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC) combined with high resolution mass spectrometry (HR-MS) for the simultaneous screening and identification of various kinds of known lipophilic and hydrophilic toxins in HAB algae was investigated for the first time. Ultrasound-assisted extraction (UAE) was explored to extract both lipophilic and hydrophilic toxins in algae simultaneously. As in most cases, toxin standards were not available; therefore, an identification procedure based on accurate mass data and chromatographic behavior was proposed. According to this procedure, eight known lipophilic toxins and 11 hydrophilic toxins were successfully detected in a single injection, and the proposed method was validated. Satisfactory sensitivity, repeatability (RSD <14.87%) and recovery (89.4–105.8%) of the method were achieved. A major advantage of the proposed method is that it can almost detect members of all eight groups of marine algal toxins in a single run. Using this method, several known toxins in different marine toxigenic algae including Alexandrium tamarense , Alexandrium minutum and Prorocentrum lima were successfully observed and identified. This work demonstrates that RPLC/HILIC-HR-MS combined with an accurate mass list of known marine algal toxins may be used as a powerful tool for screening of different classes of known toxins in marine harmful algae. [ABSTRACT FROM AUTHOR]

Summary The terminal stages of pulmonary development, called sacculation and alveologenesis, involve both differentiation of distal lung endoderm progenitors and extensive cellular remodeling of the resultant epithelial lineages. These processes are coupled with dramatic expansion of distal airspace and surface area. Despite the importance of these late developmental processes and their relation to neonatal respiratory diseases, little is understood about the molecular and cellular pathways critical for their successful completion. We show that a histone deacetylase 3 (Hdac3)-mediated epigenetic pathway is critical for the proper remodeling and expansion of the distal lung saccules into primitive alveoli. Loss of Hdac3 in the developing lung epithelium leads to a reduction of alveolar type 1 cell spreading and a disruption of lung sacculation. Hdac3 represses miR-17-92 expression, a microRNA cluster that regulates transforming growth factor β (TGF-β) signaling. De-repression of miR-17-92 in Hdac3-deficient lung epithelium results in decreased TGF-β signaling activity. Importantly, inhibition of TGF-β signaling and overexpression of miR-17-92 can phenocopy the defects observed in Hdac3 null lungs. Conversely, loss of miR-17-92 expression rescues many of the defects caused by loss of Hdac3 in the lung. These studies reveal an intricate epigenetic pathway where Hdac3 is required to repress miR-17-92 expression to allow for proper TGF-β signaling during lung sacculation. [ABSTRACT FROM AUTHOR]

Wide-area measurement systems enable the wide-area damping controller (WADC) to use remote signals to enhance the small signal stability of large scale interconnected power systems. System operating condition variations and signal transmission time delays are the major factors to worsen the damping effect and even deteriorate the system stability. This paper proposes a novel measurement-based adaptive wide-area damping control scheme using oscillation mode prediction and system identification techniques. These techniques adjust the parameters of WADC as well as the time delay compensation in an online environment. To achieve fast online implementation, an identified high order multi-input multi-output (MIMO) model is deformed into a low order single-input single-output (SISO) model according to the residue of MIMO model. The SISO model can accurately represent the power system dynamics in the form of a transfer function, capturing the dominant oscillatory behaviors in the frequency range of interest. Moreover, the WADC has been implemented on a hardware test-bed (HTB) by adding its output signal to the excitation system of a selected generator. The effectiveness of the proposed measurement-based adaptive WADC has been demonstrated in a two-area four-machine system on the HTB under various disturbance scenarios. [ABSTRACT FROM AUTHOR]

Abstract: Ziziphus jujube leaf tea (ZJLT 1 [1] ZJLT is the abbreviation of Ziziphus jujube leaf tea. ) is a new type of plant tea that has recently gained popularity in China. ZJLT is often advertised by its manufacturer for its special capacity to improve sleep. However, the suitability of drinking ZJLT at night still lacks scientific basis. This work aims to identify the typical phytochemical components in ZJLT infusion and try providing a scientific basis for drinking at night. An efficient liquid chromatography–diode array detector with time-of-flight mass spectrometry (LC–DAD–TOF/MS) method and online 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay were performed to clarify the principal bioactive compounds of ZJLT. First, caffeine and theophylline, which have important functions in refreshing the human body, were not detected in the ZJLT infusion. Second, the ZJLT infusion contains rich flavonoids, mainly flavonol glycosides, with possible sedative and hypnotic activities. Finally, a number of free radical scavengers were screened out in the ZJLT infusion. In this research, the comprehensive bioactive component information showed that ZJLT does not contain refreshing components; rather, ZJLT contains rich possibly sedative flavonoids and antioxidants. Hence, based exclusively on its chemical composition, ZJLT may be suitable for drinking at night. [Copyright &y& Elsevier]

Abstract: Cell adhesion and spreading require integrins-mediated cell–extracellular matrix interaction. Integrins function through binding to extracellular matrix and subsequent clustering to initiate focal adhesion formation and actin cytoskeleton rearrangement. Lipid raft, a liquid ordered plasma membrane microdomain, has been reported to play major roles in membrane motility by regulating cell surface receptor function. Here, we identified that lipid raft integrity was required for β1 integrin-mediated initial spreading of melanoma A375 cells on fibronectin. We found that lipid raft disruption with methyl-β-cyclodextrin led to the inability of focal adhesion formation and actin cytoskeleton rearrangement by preventing β1 integrin clustering. Furthermore, we explored the possible mechanism by which lipid raft regulates β1 integrin clustering and demonstrated that intact lipid raft could recruit and modify some adaptor proteins, such as talin, α-actinin, vinculin, paxillin and FAK. Lipid raft could regulate the location of these proteins in lipid raft fractions and facilitate their binding to β1 integrin, which may be crucial for β1 integrin clustering. We also showed that lipid raft disruption impaired A375 cell migration in both transwell and wound healing models. Together, these findings provide a new insight for the relationship between lipid raft and the regulation of integrins. [Copyright &y& Elsevier]

Abstract: Phthalate esters (PAEs) are globally pervasive contaminants that are considered to be endocrine disruptor chemicals and toxic environmental priority pollutants. In this paper, the interactions between PAEs and human serum albumin (HSA) were examined by molecular modelling, steady state and time-resolved fluorescence, ultraviolet–visible spectroscopy (UV–vis) and circular dichroism spectroscopy (CD). The association constants between PAEs and HSA were determined using the Stern–Volmer and Scatchard equations. The binding of dimethyl phthalate (DMP) to HSA has a single class of binding site and its binding constants (K) are 4.08×103, 3.97×103, 3.45×103, and 3.20×103 Lmol−1 at 289, 296, 303, and 310K, respectively. The Stern–Volmer and Scatchard plots both had two regression curves for HSA–butylbenzyl phthalate (BBP) and HSA–di-2-ethylhexyl phthalate (DEHP), which indicated that these bindings were via two types of binding sites: the numbers of binding site for the first type were lower than for the second type. The binding constants of the first type binding site were higher than those of the second type binding site at corresponding temperatures, the results suggesting that the first type of binding site had high affinity and the second binding site involved other sites with lower binding affinity and selectivity. The thermodynamic parameters of the binding reactions (ΔG°, ΔH° and ΔS°) were measured, and they indicated the presences of hydrophobic forces and hydrogen interactions in the PAEs–HSA interactions, which agreed well with the results from molecular modelling. The alterations of protein secondary structure in the presence of PAEs were confirmed by UV–vis and CD spectroscopy. The time-resolved fluorescence study showed that the lifetime of Trp residue of HSA decreased after the addition of PAEs, which implied that the Trp residue of HSA was the main binding site. [Copyright &y& Elsevier]

Abstract: In this paper, we proposed an approach using a multi-walled carbon nanotubes (MWCNTs)/Nafion composite coating as a working electrode for the electrochemically enhanced solid-phase microextraction (EE-SPME) of charged compounds. Suitable negative and positive potentials were applied to enhance the extraction of cationic (protonated amines) and anionic compounds (deprotonated carboxylic acids) in aqueous solutions, respectively. Compared to the direct SPME mode (DI-SPME) (without applying potential), the EE-SPME presented more effective and selective extraction of charged analytes primarily via electrophoresis and complementary charge interaction. The experimental parameters relating to extraction efficiency of the EE-SPME such as applied potentials, extraction time, ionic strength, sample pH were studied and optimized. The linear dynamic range of developed EE-SPME-GC for the selected amines spanned three orders of magnitude (0.005–1μgmL−1) with R 2 larger than 0.9933, and the limits of detection were in the range of 0.048–0.070ngmL−1. All of these characteristics demonstrate that the proposed MWCNTs/Nafion EE-SPME is an efficient, flexible and versatile sampling and extraction tool which is ideally suited for use with chromatographic methods. [Copyright &y& Elsevier]

Abstract: A sequential extraction procedure followed by HPLC–ICP-MS analysis was developed for the speciation and quantization of arsenic species in dry seafood products (DSPs). The extraction process involved three major steps, which produced respectively three As fractions: non-polar (Asnonpolar), polar (Aspolar) and inorganic arsenic species (Asinorganic). The extraction efficiency (EE%) is in the range of 87–115%. Asnonpolar is 0.6–10.2% of total arsenic in DSPs, which is served as the index of level of arsenolipid. For Aspolar and Asinorganic, a hyphenated HPLC–ICP-MS technique was established for the separation and quantification of six arsenic species including arsenobetaine (AsB), arsenocholine (AsC), arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The results indicate that AsB and AsV are the two dominate species in DSPs, while all other species are present in relatively low concentrations. The recovery efficiency of 77–02.8% could be obtained with spike recovery test in this two-steps extraction. [Copyright &y& Elsevier]

Abstract: A versatile, relatively selective, chemically and mechanically robust solid-phase microextraction (SPME) fiber based on methacrylic acid–trimethylolpropanetrimethacrylate (MAA/TRIM) co-polymers was developed in a simple way and directly coupled with gas chromatography. Thus, using a glass capillary as a “mold”, MAA/TRIM co-polymers were immobilized on a stainless steel wire base as a novel coating for SPME. The extraction performance of the MAA/TRIM-coated fiber was evaluated in detail using four triazines as model compounds, and several typical and important species of chemical compounds including opioids, xanthic alkaloids and phenoxyacetic acid herbicides were selected as additional examples to further illustrate the extraction mechanism and applicability of the fiber. The fiber showed high extraction efficiency for highly functionalized molecules (typically containing multiple amino, hydroxy, carbonyl and carboxy groups) via a hydrogen-bonding extraction mechanism. The maximum extraction ability and selectivity of the fiber could be obtained only in non-polar (aprotic) organic solvents, which are effective for the hydrogen-bonding interaction. The inherent chemical stability of MAA/TRIM co-polymers and the mechanical strength of the stainless steel wire as the fiber support made the MAA/TRIM-coated fiber highly durable in practical use. [Copyright &y& Elsevier]

Abstract: An approach to the synthesis of hydroxyl-terminated polymethylphenylsiloxane (PMPS-OH) was proposed and the synthesized PMPS-OH was successfully applied as a precursor to prepare a novel coating for solid-phase microextraction (SPME) via the sol–gel process. The thickness and length of the prepared coating was 70μm and 1.5cm, respectively. The extraction efficiency of the PMPS-coated fiber for selected pesticides was higher than that of commercial fibers including 100μm polydimethylsiloxane (PDMS), 85μm polyacrylate (PA) and 65μm polydimethylsiloxane/divinylbenzene (PDMS/DVB). The influence of the extraction process, extraction temperature, extraction time, stirring rate, ionic strength, GC inlet conditions, desorption temperature and time for PMPS-coated fiber application was studied and optimized. Several experiments were carried out to evaluate the analytical characteristics of the proposed SPME–GC-ECD method under optimized conditions. The linearity was from 0.5 to 100ngg−1 for p,p′-DDE, p,p′-DDD and bifenthrin, and from 2 to 100ngg−1 for o,p′-DDT, p,p′-DDT, fenpropathrin, beta-cyfluthrin and cyhalothrin. The detection limits of these pesticides were between 0.13 and 1.45ngg−1. The recovery of the pesticides spiked in various vegetables at 4ngg−1 ranged from 42.9% to 105.3%, and the relative standard deviations were less than 16.2%. [Copyright &y& Elsevier]

Abstract: A new method based on accelerated solvent extraction (ASE) followed by ultra performance liquid chromatography (UPLC) analysis has been developed for the identification and quantification of major alkaloids in extracts of Coptis chinensis Franch. The UPLC system consisted of a dual detection system of photodiode array detector (PDA) and positive ion electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in sequential configuration. The operational parameters of ASE including extraction solvent, extraction temperature, static extraction time and extraction cycles were optimized. UPLC analysis was performed on an ACQUITY UPLC BEH C18 column eluted by a mobile phase of acetonitrile spiked with a buffer solution consisting of 0.50% acetic acid and 20mmolL−1 ammonium acetate. A tandem quadrupole spectrometer operating in either full scan mode or in MS/MS mode for multiple reaction monitoring (MRM) was used for the identification and quantitative analysis of eight major alkaloids in C. chinensis Franch extracts. The samples were also analyzed on a high-performance liquid chromatography–electrospray ionization-time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) system to confirm the identification results. Three of the eight major alkaloids, berberine, palmatine and jatrorrhizine were quantified by UPLC–PDA and UPLC–MS/MS. The results indicated that both UPLC–PDA and UPLC–MS/MS methods were simple, sensitive and reliable for the determination of alkaloids in C. chinensis Franch. Seven Huanglian samples from different locations were analyzed using the established methods. UPLC fingerprints based on the distribution of the eight major alkaloids can serve as a rapid and reliable method for the authentication and quality evaluation of traditional Chinese medicine (TCM) herbs. [Copyright &y& Elsevier]

Abstract: A ceramic/carbon composite was developed and applied as a novel coating for solid-phase microextraction (SPME). The ceramic/carbon coating exhibited several good properties for SPME, such as high extraction quantities and enhanced thermal and organic solvent stability. Under scanning electron microscopy (SEM), the tightly attached coating layer on stainless steel wire revealed excellent mechanical characteristics. Single fiber and fiber-to-fiber reproducibility were less than 6.9 and 9.5%, respectively. The effects of extraction and desorption parameters such as extraction time, stirring rate, ionic strength, and desorption temperature and desorption time on the extraction/desorption efficiency were investigated and optimized. Coupled to gas chromatography with a flame thermionic detector, the optimized SPME method was applied to the analysis of organophosphorus pesticides (OPPs) in aqueous samples. The calibration curves were linear from 0.05 to 200ngmL−1 for fenchlorphos, pirimiphos-methyl, chlorpyrifos, ethion and from 0.2 to 200ngmL−1 for quinalphos, and the limits of detection were between 5.2 and 34.6ngL−1. The recovery of the OPPs spiked in real water samples at 5ngmL−1 ranged from 86.2 to 103.4% and the relative standard deviations were less than 8.5%. [Copyright &y& Elsevier]

Abstract: Amino acids with different chemical structures have different abilities in terms of increasing the intensity of chemiluminescence (CL) of tris(2,2′-bipyridine)ruthenium(II) [Ru(bpy)3 2+]. In a flow system, CL caused by the reaction between Ru(bpy)3 3+ and 15 amino acids was observed, but only tryptophan (Trp) and histidine (His) enhanced the intensity obviously, and so the CL of Trp and His and their molecular groups was studied. A calculation of the ionization potentials (IPs) of their N atom indicated that the CL intensities of these compounds depended on their IPs. In addition, the flow system was used for the determination of Trp and His, and the detection limits were 3×10−8 molL−1 for His and 2.5×10−9 molL−1 for Trp. The calibration curves for the two amino acids were 1.0×10−7 to 5.0×10−3 molL−1 for His and 1.0×10−8 to 1.0×10−4 molL−1 for Trp. The proposed approach was applied to the determination of His in Ganoderma. [Copyright &y& Elsevier]

Abstract: High-performance liquid chromatographic (HPLC) was developed for fingerprint analysis of Pseudostellaria heterophylla (Miq.) Pax. Liquid chromatography–electrospray ionization-time-of-flight mass spectrometry (LC–TOF-MS) technique was first employed to identify the components of the fingerprint. Twelve major peaks in chromatographic fingerprint were analyzed by on-line LC–TOF-MS analysis; one cyclic peptide was unequivocally identified and five cyclic peptides were tentatively assigned based on their MS data. These cyclic peptides served as the marker peaks in the HPLC fingerprints. The chromatographic fingerprints have been analyzed by similarity index calculations and hierarchical clustering analysis (HCA). The result showed that the HPLC fingerprints could be used to determine the optimal harvest time for P. heterophylla (Miq.) Pax and to authenticate the species of the herb. [Copyright &y& Elsevier]

Abstract: Intestinal mucus (foregut mucus and hindgut mucus) extracted from large yellow croakers was used as a model of investigating the adhesion of pathogenic Vibrio alginolyticus by the method of isotope tracer. The results showed that pathogenic V. alginolyticus could adhere to the intestinal mucus of large yellow croaker strongly. The bacterial adhesion to foregut mucus and hindgut mucus reached equilibrium after incubated at 25 °C for 150 min and 180 min, respectively. The bacterial adhesion was influenced remarkably by environmental factors such as temperature, pH and salinity, and the maximal adhesion was achieved at 30 °C, acidic condition and the normal values of salinity of marine environment (35). Starved bacteria had no adhesive capacity. Lactic acid could inhibit the bacterial adhesion. In addition, the adhesion of V. alginolyticus depended on Na+, while Ca2+ or Mg2+ played an auxiliary role in bacterial adhesion. Results obtained from adhesion assaying under various conditions (heat treatment, protease and periodic acid treatment) indicated that the main components involved in the adherence process of V. alginolyticus to the intestinal mucus might be glycoproteins. The results of adhesion assay after the mucus was roughly fractionated by gel filtration chromatography showed that the components with highest affinity might be the higher molecular mass. Our results indicated that the bacterial adhesion was governable, which might be useful for the epidemic control in fish culture. [Copyright &y& Elsevier]

Abstract: A new method based on accelerated solvent extraction (ASE) followed by a reliable high-performance liquid chromatography-diode array detector (HPLC-DAD) and positive ion electrospray-time of flight mass spectrometry (ESI-TOF/MS) analysis has been developed for the characterization and quantification of four major saponins in extracts of the seeds of Aesculus chinensis Bunge (Semen Aesculi). The saponins escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted from seeds of A. chinesis Bunge via ASE, and the operational parameters of ASE were optimized, such as extraction solvent, extraction temperature, static extraction time and extraction cycles. The optimized procedure employed 70% MeOH as extraction solvent, 120°C of extraction temperature, 7min of static extraction time, 60% flush volume and the extraction recoveries of the four compounds were nearly to 100% for two cycles. The HPLC conditions are as follows: SinoChrom ODS BP C18 (4.6mm×200mm, 5μm) column, acetonitrile and 0.10% phosphoric acid solution as mobile phase, flow rate is 1.0mLmin−1, detection length of UV is 203nm, injection volume is 10μL. The results indicated that the developed HPLC method is simple, sensitive and reliable for the determination of four major saponins in seeds of A. chinesis Bunge with a good linearity (r 2 >0.9994), precision (relative standard deviation (R.S.D.) <1.5%) and the recovery ranges of 95.2–97.3%. The limits of detection (LOD) of the four compounds were in the range of 0.40–0.75μgmL−1. This assay can be readily utilized as a quality control method for Semen Aesculi and other related medicinal plants. [Copyright &y& Elsevier]

Abstract: A solid-phase microextraction (SPME) method has been developed for the determination of 3 chloroacetanilide herbicides in both fresh and seawater samples. The extracted sample was analyzed by gas chromatography with mass spectrometry detection (GC–MS), and parameters affecting SPME operation including fibre type, sample pH, sample temperature, mixing speed and extraction time have been evaluated and optimized. The amount of dissolved organic matter (DOM) and the salt content both affected SPME extraction efficiency, but the presence of other competitive extractants such as organochlorine pesticides (OCPs) in the matrix showed no insignificance interference. The limit of detection (LOD) for acetochlor, metolachlor and butachlor were 1.2, 1.6 and 2.7ngL−1, respectively. The recoveries for the herbicides ranged from 79 to 102%, and the linear dynamic range was from 10 to 1000ngL−1. The developed method has been used to monitor herbicides contaminations in coastal water samples collected around Laizhou bay and Jiaozhou bay in Shandong peninsula, China. The concentrations of acetochlor and metolachlor ranged from undetectable to 78.5ngL−1 and undetectable to 35.6ngL−1, respectively. Butachlor was not observed but in only one sample and the concentration is lower than the limit of quantification (LOQ). The concentrations of the three herbicides in this study are low compared to most of the other places reported. [Copyright &y& Elsevier]

The extent of organochlorine pesticides (OCPs) contamination in coastal waters around LaiZhou Bay and JiaoZhou Bay in Shandong Peninsula, northern China, was investigated. The areas around the two bays are both densely populated, thrived with intensive agriculture and industrial activities. Multi-techniques including GC–MS, GC–μECD coupled with chemical peak confirmation and strict QC procedures were used for the quantitative determination of 15 OCPs including alpha, beta, gamma and delta isomers of hexachlorocyclohexane (HCH), pentachloronitrobenzene (PCNB), heptachlor, aldrin, endosulfan, p,p′-DDE, dieldrin, endrin, p,p′-DDD, o,p′-DDT, p,p′-DDT and methoxychlor. The survey results show that contaminations by OCP residues remain widespread in the areas, but the averaged concentration levels are all below the regulatory limits, e.g., CMC limits (acute criterion values) specified in US Environmental Protection Agency (USEPA) and China national standards. Average concentration of OCPs in water samples were from undetectable to 3. 8ngl−1 in LaiZhou Bay and from 0. 1 to 3. 9ngl−1 in JiaoZhou Bay, respectively. A comparison between the current and historical data shows a rapidly decreasing trend of OCPs over the past twenty years in the study areas. [Copyright &y& Elsevier]

Abstract: Oxygen sensors prepared from tetramethyl orthosilicate and dimethoxy dimethylsilane with tris(4,7-diphenyl-1,10-phenanthroline)ruthenium (II) as the sensing dye were coated onto the well bottom surface of a 96-well polystyrene microtiter plate to give a high-throughput system for dissolved oxygen measurement. The oxygen sensors give linear Stern–Volmer calibration plots, and produce reliable and reproducible results in the determination of IC50 values of drugs on a yeast model. [Copyright &y& Elsevier]

Abstract: A HPLC fingerprinting method based on the distribution and contents of seven major ginsenosides has been developed for the quality evaluation of Panax quinquefolium. L roots cultivated in China, Singapore and Canada. The method is ideally suited for the fingerprinting of P. quinquefolium. L samples or its derived products for sample authentication or quality control, e.g. pharmaceutical stability studies. Different extraction methods have been evaluated and a protocol established to maximize the gensinosides yields in routine operations. Hierarchical clustering analysis of the fingerprints demonstrates that the distribution and contents of ginsenosides in P. quinquefolium. L root vary depending on geographic location; and the quality of Jilin-cultivated P. quinquefolium. L roots is similar in composition to Canada-cultivated ones, which are generally considered among the best quality in P. quinquefolium. L. [Copyright &y& Elsevier]