[Determination of twelve halobenzoquinones in drinking water by solid phase extraction-ultra-performance liquid chromatography-tandem mass spectrometry].

OBJECTIVE: To establish a method for twelve halobenzoquinones(HBQs) in drinking water by solid phase extraction-ultra-performance liquid chromatography coupled with electrospray-tandem mass spectrometry(SPE-UPLC-MS/MS). METHODS: The drinking water was acidified with formic acid and concentrated by Bond Elut Plexa solid phase extraction column. The sample solution was separated using Waters ACQUITY HSS T3 column(100 mm×2.1 mm, 1.8 µm) with gradient elution using methanol-water containing 0.1% formic acid as mobile phase. The target compouds were detected in negtive electrospray ionization(ESI~-) and multiple reaction monitoring. RESULTS: The concentration of twelve HBQs showed good linearity in the range 5.0-150.0 ng/mL, respectively, with the correlation coefficients greater than 0.999. The limits of detection(LOD) of twelve HBQs were lower than 2.0 ng/mL, and the limits of quantification(LOQ) for twelve HBQs were lower than 5.0 ng/mL, respectively. The recoveries of three levels in the matrix were 70.0%-84.0%. The matrix effffect was 0.08-0.64. CONCLUSION: The SPE-UPLC-MS/MS method has high sensitivity, good accuracy and fast analysis speed for the detection of halobenzoquinones in drinking water.

Chemical composition and therapeutic mechanism of Xuanbai Chengqi Decoction in the treatment of COVID-19 by network pharmacology, molecular docking and molecular dynamic analysis.

Xuanbai Chengqi Decoction (XBCQD), a classic traditional Chinese medicine, has been widely used to treat COVID-19 in China with remarkable curative effect. However, the chemical composition and potential therapeutic mechanism is still unknown. Here, we used multiple open-source databases and literature mining to select compounds and potential targets for XBCQD. The COVID-19 related targets were collected from GeneCards and NCBI gene databases. After identifying putative targets of XBCQD for the treatment of COVID-19, PPI network was constructed by STRING database. The hub targets were extracted by Cytoscape 3.7.2 and MCODE analysis was carried out to extract modules in the PPI network. R 3.6.3 was used for GO enrichment and KEGG pathway analysis. The effective compounds were obtained via network pharmacology and bioinformatics analysis. Drug-likeness analysis and ADMET assessments were performed to select core compounds. Moreover, interactions between core compounds and hub targets were investigated through molecular docking, molecular dynamic (MD) simulations and MM-PBSA calculations. As a result, we collected 638 targets from 61 compounds of XBCQD and 845 COVID-19 related targets, of which 79 were putative targets. Based on the bioinformatics analysis, 10 core compounds and 34 hub targets of XBCQD for the treatment of COVID-19 were successfully screened. The enrichment analysis of GO and KEGG indicated that XBCQD mainly exerted therapeutic effects on COVID-19 by regulating signal pathways related to viral infection and inflammatory response. Meanwhile, the results of molecular docking showed that there was a stable binding between the core compounds and hub targets. Moreover, MD simulations and MM-PBSA analyses revealed that these compounds exhibited stable conformations and interacted well with hub targets during the simulations. In conclusion, our research comprehensively explained the multi-component, multi-target, and multi-pathway intervention mechanism of XBCQD in the treatment of COVID-19, which provided evidence and new insights for further research.

[Determination of beauvercin and enniatins in rice flour and wheat flour by solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry].

OBJECTIVE: To develop a method for the determination of beauvercin(BEA), enniatin A(ENNA), enniatin A1(ENNA1), enniatin B(ENNB) and enniatin B1(ENNB1) in rice flour and wheat flour by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS: Samples were extracted by acetonitrile-water, purified by Oasis Prime HLB solid-phase extraction column. The sample solution was separated by waters BEH C_(18) column(2.1 mm×100 mm, 1.8 µm). The detection was performed in the electrospray positive ionization(ESI+) under multiple reaction monitoring(MRM) mode. The internal standard method and the matrix-matched calibrations were used for quantification. RESULTS: The linear relationships of BEA and 4 kinds of enniatins(ENNs) were good in the range of 0.1-50.0 ng/mL(r>0.999). The average recoveries of BEA and ENNs in rice flour and wheat flour were 96.4%-105.4% and 99.1%-109.2%, with the relative standard deviations(RSD) of 1.01%-7.42% and 1.09%-9.69%(n=6). The detection limits(LOD) of BEA and ENNs were 0.03 µg/kg. The quantitative limits(LOQ) of BEA and ENNs were 0.1µg/kg. The matrix induced suppression or enhancement effect were 72.7%-99.3% and 60.8%-100.4%, respectively. The levels of emerging BEA and ENNs in wheat flour were higher than rice flour. The detection rate of enniatin B was highest in wheat flour and rice flour, the contents were 0.03-9.57 µg/kg and 0.03-0.56 µg/kg, the positive percentage were 98.5% and 36.4%. CONCLUSION: The method is quick, easy, accurate and sensitive, which is suitable for the determination of BEA and 4 kinds of ENNs in rice flour and wheat flour.

SOSTDC1 acts as a tumor inhibitor in acute myeloid leukemia by downregulating the Wnt/ß-catenin pathway.

Sclerostin domain-containing 1 (SOSTDC1) has been documented as a key tumor-associated protein that is differentially expressed in multiple malignancies. However, the function of SOSTDC1 in acute myeloid leukemia (AML) is unexplored. The goal of this work was to assess the possible role of SOSTDC1 in AML. Our data showed decreased SOSTDC1 level in bone marrow from AML patients, and patients with low levels of SOSTDC1 had a reduced survival rate. SOSTC1 upregulation restrained the proliferative ability and promoted the apoptotic rate of AML cells. SOSTDC1 suppressed the activation of the Wnt/ß-catenin pathway in AML cells. Reactivation of the Wnt/ß-catenin pathway reversed SOSTDC1-mediated antitumor effects. SOSTDC1 upregulation weakened the tumorigenicity of AML cells in vivo. Collectively, our work demonstrates that SOSTDC1 has a tumor-inhibiting role in AML via downregulation of the Wnt/ß-catenin pathway. This work underscores a key function for the SOSTDC1/Wnt/ß-catenin pathway in AML.

LncRNA SNHG1 contributes to the regulation of acute myeloid leukemia cell growth by modulating miR-489-3p/SOX12/Wnt/ß-catenin signaling.

The long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) is a critical regulator for the development and progression of multiple tumors. Yet, the role of SNHG1 in acute myeloid leukemia (AML) is unknown. The present study demonstrated that SNHG1 expression was upregulated in AML. SNHG1 silencing markedly repressed AML cell growth, whereas SNHG1 overexpression had the opposite effect. MicroRNA-489-3p (miR-489-3p) was identified as a SNHG1-targeting miRNA. SNHG1 knockdown increased miR-489-3p expression. Low expression of miR-489-3p was correlated with high expression of SNHG1 in AML tissues. miR-489-3p overexpression restricted AML cell growth, and SRY-related high-mobility-group box 12 (SOX12) was identified as a miR-489-3p-targeting gene. SNHG1 inhibition or miR-489-3p overexpression inactivated Wnt/ß-catenin signaling through downregulation of SOX12. SOX12 overexpression partially reversed the SNHG1 knockdown- or miR-489-3p overexpression-mediated effects. Taken together, these data indicate that suppression of SNHG1 downregulates AML cell growth by inactivating SOX12/Wnt/ß-catenin signaling via upregulating miR-489-3p.

[Nutritional composition in different processed wheats from Shaanxi Province].

OBJECTIVE: To study the content of nutritive ingredients of 11 kinds of different processed wheats planted in Shaanxi Province, and assess their nutritional value. METHODS: The macronutrients, moisture, ash and vitamins in 11 different wheat were determined. The index of nutritional quality(INQ) method was used to evaluate the different nutrients in 11 kinds of wheat and the fuzzy membership function method was used to evaluate the nutritional value comprehensively. RESULTS: The contents of water and carbohydrate in 11 kinds of whole wheat flour were lower than those of special flour and wheat core flour. The contents of ash, fat, protein and total dietary fiber were significantly higher than those of special flour and wheat core flour. The wheat flour contained high levels of vitamin B_1, certain vitamin B_2 and trace amount of ß-carotene. Under the parameters selected in this article, the comprehensive evaluation shows that Jinmai 54 had the highest nutritive value among 11 kinds of wheat, while Zhoumai 26 had the lowest nutritive value. CONCLUSION: 11 kinds of wheat is rich in protein, vitamins and other nutrients, peeling can cause a large loss of vitamin B and vitamin E in wheat flour. The comprehensive nutritional value of whole wheat flour is higher than the special flour and wheat core powder.

Comparison of Soil Total Nitrogen Content Prediction Models Based on Vis-NIR Spectroscopy.

Visible-near-infrared spectrum (Vis-NIR) spectroscopy technology is one of the most important methods for non-destructive and rapid detection of soil total nitrogen (STN) content. In order to find a practical way to build STN content prediction model, three conventional machine learning methods and one deep learning approach are investigated and their predictive performances are compared and analyzed by using a public dataset called LUCAS Soil (19,019 samples). The three conventional machine learning methods include ordinary least square estimation (OLSE), random forest (RF), and extreme learning machine (ELM), while for the deep learning method, three different structures of convolutional neural network (CNN) incorporated Inception module are constructed and investigated. In order to clarify effectiveness of different pre-treatments on predicting STN content, the three conventional machine learning methods are combined with four pre-processing approaches (including baseline correction, smoothing, dimensional reduction, and feature selection) are investigated, compared, and analyzed. The results indicate that the baseline-corrected and smoothed ELM model reaches practical precision (coefficient of determination (R2) = 0.89, root mean square error of prediction (RMSEP) = 1.60 g/kg, and residual prediction deviation (RPD) = 2.34). While among three different structured CNN models, the one with more 1 × 1 convolutions preforms better (R2 = 0.93; RMSEP = 0.95 g/kg; and RPD = 3.85 in optimal case). In addition, in order to evaluate the influence of data set characteristics on the model, the LUCAS data set was divided into different data subsets according to dataset size, organic carbon (OC) content and countries, and the results show that the deep learning method is more effective and practical than conventional machine learning methods and, on the premise of enough data samples, it can be used to build a robust STN content prediction model with high accuracy for the same type of soil with similar agricultural treatment.

Combination of Multivariate Standard Addition Technique and Deep Kernel Learning Model for Determining Multi-Ion in Hydroponic Nutrient Solution.

Ion-selective electrodes (ISEs) have recently become the most attractive tools for the development of efficient hydroponic systems. Nevertheless, some inherent shortcomings such as signal drifts, secondary ion interferences, and effected high ionic strength make them difficult to apply in a hydroponic system. To minimize these deficiencies, we combined the multivariate standard addition (MSAM) sampling technique with the deep kernel learning (DKL) model for a six ISEs array to increase the prediction accuracy and precision of eight ions, including NO3-, NH4+, K+, Ca2+, Na+, Cl-, H2PO4-, and Mg2+. The enhanced data feature based on feature enrichment (FE) of the MSAM technique provided more useful information to DKL for improving the prediction reliability of the available ISE ions and enhanced the detection of unavailable ISE ions (phosphate and magnesium). The results showed that the combined MSAM-feature enrichment (FE)-DKL sensing structure for validating ten real hydroponic samples achieved low root mean square errors (RMSE) of 63.8, 8.3, 29.2, 18.5, 11.8, and 8.8 mg·L-1 with below 8% coefficients of variation (CVs) for predicting nitrate, ammonium, potassium, calcium, sodium, and chloride, respectively. Moreover, the prediction of phosphate and magnesium in the ranges of 5-275 mg·L-1 and 10-80 mg·L-1 had RMSEs of 29.6 and 8.7 mg·L-1 respectively. The results prove that the proposed approach can be applied successfully to improve the accuracy and feasibility of ISEs in a closed hydroponic system.

Functions of Small Organic Compounds that Mimic the HNK-1 Glycan.

Because of the importance of the HNK-1 carbohydrate for preferential motor reinnervation after injury of the femoral nerve in mammals, we screened NIH Clinical Collection 1 and 2 Libraries and a Natural Product library comprising small organic compounds for identification of pharmacologically useful reagents. The reason for this attempt was to obviate the difficult chemical synthesis of the HNK-1 carbohydrate and its isolation from natural sources, with the hope to render such compounds clinically useful. We identified six compounds that enhanced neurite outgrowth from cultured spinal motor neurons at nM concentrations and increased their neurite diameter, but not their neurite branch points. Axons of dorsal root ganglion neurons did not respond to these compounds, a feature that is in agreement with their biological role after injury. We refer to the positive functions of some of these compounds in animal models of injury and delineate the intracellular signaling responses elicited by application of compounds to cultured murine central nervous system neurons. Altogether, these results point to the potential of the HNK-1 carbohydrate mimetics in clinically-oriented settings.

[Simultaneous determination of 6 cyclohexanedione herbicides residues in potatoes by ultra-performance liquid chromatography-tandem mass spectrometry].

OBJECTIVE: To establish a method for analysis of 6 cyclohexanedione herbicides residues in potatoes by ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry( UPLC-MS/MS). METHODS: The target compounds in samples were extracted ultrasonically with acetonitrile. After centrifugation, the supernatant was cleaned up with Envi-carb column. The sample solution was separated on an Dionex C_(18) column( 2. 1 mm × 100 mm, 2. 2 µm) with gradient elution using acetonitrile -5 mmol/L ammonium acetate and 0. 1% formic acid in water as mobile phase. The identification was performed with tandem mass spectrometer, with electrospray ionization( ESI) in positive mode under multiple reaction monitoring. The quantification was based on external standard curves. RESULTS: The method showed good linearity in the range of 2-100 µg/L( r ≥ 0. 9923). The limit of quantitation were 2. 0 µg/kg. The detection limits of the method were 0. 6 µg/kg. The recoveries were within 67. 5%-95. 8% at the spiked levels of 2. 0-10. 0 µg/kg, and the relative standard deviations were all less than 8. 5%. Six cyclohexanedione herbicides residues were detected in 6. 7% of 30 potatoes samples which was determined by the method. CONCLUSION: The method is rapid, specific, accurate, and it is suitable for detection of quinolone and tetracycline residues.

[Analysis of pesticides residues in food samples in Shaanxi Province during 2013-2015].

OBJECTIVE: To investigate the status of pesticides residues in vegetables, fruits, edible mushrooms and tea bags in Shaanxi Province. METHODS: Ten cities in Shaanxi Province were selected as monitoring area, pesticides residues in food were detected by gas chromatograph-mass spectrometry. RESULTS: The total detection rate of pesticide residues was 15. 60%( 159/1019). The detection rate of pesticides in vegetables, fruits, edible mushrooms and tea bag was 18. 64%, 15. 00%, 4. 68% and23. 63%, respectively. The detection rate of organophosphorus, carbamate, pyrethroid and organochlorine was 7. 36%, 6. 48%, 8. 34% and 5. 79%, respectively. Methyl parathion, parathion, omethoate, cyhalothrin, cyhalothrin and cypermethrin were still overused in the vegetables, and the total exceeding rate was 1. 51%. CONCLUSION: The pesticides in food were detected in Shaanxi Province, but the total of exceeding standard is below the national level.

[Assessment on exposure of dietary aluminium among residents in Shaanxi Province during 2013-2015].

OBJECTIVE: To investigate the contamination condition of the aluminium in commercial foods in Shaanxi Province, and evaluate aluminium dietary intake level in Shaanxi population and its potential health risks. METHODS: 1331 samples in Shaanxi Province were collected from 2013 to 2015. The aluminium contents were detected by National Food Contamination and Harmful Factors in Risk Monitoring Manual, and data of total diet study in Shaanxi Province in 2007, to calculate dietary intake of aluminium in Shaanxi population. RESULTS: Average dietary intake of aluminium was 0. 358 mg/( kg·d), accounted for 125% of PTWI. The dietary intake of aluminium in children aged 2 to7 years old was highest, followed children aged 8 to 12 years old and men aged 13 to 19 years old. Grain products and potato products were the main sources of aluminium exposure compared with others. CONCLUSION: The dietary intake of aluminium in Shaanxi population is more than the PTWI. The children aged 2 to 7 years old, children aged 8 to12 years old and men aged 13 to 19 years old is high. Grain products and potato products are the main sources of aluminium exposure in Shaanxi population. The effective measureto control the intake of aluminium is to normalize and rationalize the use of additives containing aluminium.

[Analysis on contamination of zearalenone and dietary exposure assessment in food samples of Shaanxi Province in 2013-2016].

OBJECTIVE: To investigate the contamination of zearalenone in food in Shaanxi Province, and to assess the dietary zearalenone exposure and the health risk of intaking zearalenone from corn products for Shaanxi residents. METHODS: In 2013-2016, samples of five kinds of food including grains, vegetable oil, liquor and infants' food were collected randomly from ten cities, and determined with ultra-performance liquid chromatography. Dietary intake assessment of human exposure to zearalenone was carried out in combination of food consumption data with concentration of zearalenone. RESULTS: 1193 samples were detected zearalenone and the total detection rate was 17. 27%, with the mean value of 13. 5 µg/kg. Among all food samples, oil products were more seriously polluted than other kinds of foods, its detection rate was 79. 37%. And 12 samples of grain products exceed the standard, the exceeding standard rate was 1. 64%, which were all corn products. The level of zearalenone detected in wheat flour, rice, millet, beer and bakery products was low. CONCLUSION: The overall level of zearalenone contamination inmarket food is common, but corn products may be the severely contaminated foods with zearalenone in Shaanxi Province. The risk assessmentresult suggests that the current dietary intake of zearalenone from corn products in Shaanxi Province has no appreciable effect on health, however, the concentrations of zearalenone in corn products are relatively high, and need to be monitored in the future.

Tunable spiral Bragg gratings in 60-nm-thick silicon-on-insulator strip waveguides.

We demonstrate spiral integrated Bragg gratings (IBGs) in 60-nm-thick strip waveguides on the silicon-on-insulator (SOI) platform. The length of the spiral IBG is 2 mm, occupying an area of 147 × 141 µm2 with a minimum bending radius of 20 µm. Experiments show that the spiral IBGs exhibit a single narrow transparent peak with a Q-factor of 1 × 105 in a broad stopband, induced by the phase shift of the S-junction at the spiral center. This phenomenon is analogous to the electromagnetically induced transparency (EIT) effect. The transparent peak can periodically shift in the stopband upon heating of the S-junction using a TiN-based heater on top. The peak transmittance and Q-factor are dependent on the reflectivity of the spiral IBG. The transparent peak can be completely eliminated under a certain tuning power, and the spiral IBG hence behaves as a bandstop optical filter. The bandwidth is 0.94 nm and the extinction ratio is as high as 43 dB. The stopband can also be shifted by heating the Bragg gratings using a separate TiN heater. The experimental results agree well with the modeling results based on the transfer matrix method.

16 × 16 non-blocking silicon optical switch based on electro-optic Mach-Zehnder interferometers.

We experimentally demonstrate a 16 × 16 non-blocking optical switch fabric with a footprint of 10.7 × 4.4 mm2. The switch fabric is composed of 56 2 × 2 silicon Mach-Zehnder interferometers (MZIs), with each integrated with a pair of TiN resistive micro-heaters and a p-i-n diode. The average on-chip insertion loss at 1560 nm wavelength is ~6.7 dB and ~14 dB for the "all-cross" and "all-bar" states, respectively, with a loss variation of ± 1 dB over all routing paths. The measured rise/fall time of the switch upon electrical tuning is 3.2/2.5 ns. The switching functionality is verified by transmission of 20 Gb/s on-off keying (OOK) and 50 Gb/s quadrature phase-shift keying (QPSK) optical signals.

[Analysis on contamination of aflatoxins in food samples in Shaanxi Province from 2012-2015].

OBJECTIVE: To investigate the contamination of aflatoxins in food in Shaanxi Province, and provide the basic data of dietary intakes of aflatoxins for food safety assessment. METHODS: In year 2012- 2015, 1007 food samples of eight kinds of food including grains, beans, vegetable oil, nuts and seeds, condiment, liquor, tea and infants' food were collected randomly from ten cities, and determined with UPLC. RESULTS: 1007 samples were detected aflatoxins and the total detection rate was 10. 7%. The detection range was 0. 070- 323 µg / kg, with the mean value of 2. 34 µg / kg. Among all food samples, only peanut products were more seriously polluted than other kinds of foods. CONCLUSION: The overall level of aflatoxins contamination in market food is low, but peanut products might be the contaminated foods with aflatoxins in Shaanxi Province, and should be given more attention.

Effects of different elevated CO2 concentrations on chlorophyll contents, gas exchange, water use efficiency, and PSII activity on C3 and C4 cereal crops in a closed artificial ecosystem.

Although terrestrial CO2 concentrations [CO2] are not expected to reach 1000 µmol mol(-1) (or ppm) for many decades, CO2 levels in closed systems such as growth chambers and greenhouses can easily exceed this concentration. CO2 levels in life support systems (LSS) in space can exceed 10,000 ppm (1 %). In order to understand how photosynthesis in C4 plants may respond to elevated CO2, it is necessary to determine if leaves of closed artificial ecosystem grown plants have a fully developed C4 photosynthetic apparatus, and whether or not photosynthesis in these leaves is more responsive to elevated [CO2] than leaves of C3 plants. To address this issue, we evaluated the response of gas exchange, water use efficiency, and photosynthetic efficiency of PSII by soybean (Glycine max (L.) Merr., 'Heihe35') of a typical C3 plant and maize (Zea mays L., 'Susheng') of C4 plant under four CO2 concentrations (500, 1000, 3000, and 5000 ppm), which were grown under controlled environmental conditions of Lunar Palace 1. The results showed that photosynthetic pigment by the C3 plants of soybean was more sensitive to elevated [CO2] below 3000 ppm than the C4 plants of maize. Elevated [CO2] to 1000 ppm induced a higher initial photosynthetic rate, while super-elevated [CO2] appeared to negate such initial growth promotion for C3 plants. The C4 plant had the highest ETR, φPSII, and qP under 500-3000 ppm [CO2], but then decreased substantially at 5000 ppm [CO2] for both species. Therefore, photosynthetic down-regulation and a decrease in photosynthetic electron transport occurred by both species in response to super-elevated [CO2] at 3000 and 5000 ppm. Accordingly, plants can be selected for and adapt to the efficient use of elevated CO2 concentration in LSS.

Tuning the switching behavior of binary oxide-based resistive memory devices by inserting an ultra-thin chemically active metal nanolayer: a case study on the Ta2O5-Ta system.

The common nonpolar switching behavior of binary oxide-based resistive random access memory devices (RRAMs) has several drawbacks in future application, such as the requirements for a high forming voltage, a large reset current, and an additional access device to settle the sneak-path issue. Herein, we propose the tuning of the switching behavior of binary oxide-based RRAMs by inserting an ultra-thin chemically active metal nanolayer, and a case study on Ta2O5-Ta systems is provided. The devices are designed to be Pt/Ta2O5(5 - x/2)/Ta(x)/Ta2O5(5 - x/2)/Pt with x = 0, 2, or 4 nm. The reference devices without the Ta nanolayer exhibit an expected nonpolar switching behavior with a high forming voltage of ∼-4.5 V and a large reset current of >10 mA. In contrast, a self-compliance bipolar switching behavior with a low forming voltage of ∼-2 V and a small reset current of <1 mA is observed after inserting a 2 nm Ta nanolayer. When the Ta nanolayer is increased to 4 nm, a complementary resistive switching (CRS) behavior is found, which can effectively settle the sneak-path issue. The appearance of CRS behavior suggests that a thin Ta nanolayer of 4 nm is robust enough to act as an inner electrode. Besides, the behind switching mechanisms are thoroughly discussed with the help of a transmission electron microscope and temperature-dependent electrical measurements. All these results demonstrate the feasibility of tuning switching behavior of binary oxide-based RRAMs by inserting an ultra-thin chemically active metal nanolayer and might help to advance the commercialization of binary oxide-based RRAMs.

[Survey and evaluation of heavy metal in the major vegetables in Shaanxi Province].

OBJECTIVE: To evaluate the contamination condition of the Pb, Cd, Hg and As in ten kinds of vegetables in Shaanxi Province. METHODS: The Pb and Cd contents were determined by inductively coupled plasma mass spectrometry, and the As contents were determined by hydride generation-atomic fluorescence spectrometry, and the Hg contents were determined by mercury vapourmeter. One factor contamination index was employed to evaluate the metal pollution situation of different types of vegetables. Moreover, the health risk after intake of those heavy metals through vegetables were described. RESULTS: In ten kinds of vegetables of Shaanxi Province, the Pb contents in cowpea reached the alertness level, while the contents of Cd, Hg and As were below the safety level. What' s more, the contents of the Pb, Cd, Hg and As were below the safety level in other nine vegetables, and the over standard rate of were Hg > Pb > Cd > As. CONCLUSION: The contamination extents of Pb, Cd, Hg and As in ten kinds of vegetables in Shaanxi Province were low.

[Investigation on contamination situation of malachite green in freshwater fish and its dietary exposure assessment of Shaanxi Province].

OBJECTIVE: To investigate the residue levels of malachite green (MG) in freshwater fish and assess the dietary MG exposure of Shaanxi residents. The second aim was to assess the health risk of intaking MG from freshwater fish for Shaanxi residents. METHODS: The samples were determined by UPLC-MS/MS after purified by neutral alumina SPE cartridges and separated by waters-BEH C18 column (2.1 mm x 100 mm, 2.5 µm). The MOE method was used to assess the risk of intaking MG from freshwater fish for Shaanxi residents. RESULTS: The average detection rate of MG in freshwater fish in Shaanxi province was 7.32% and the highest residue level was 428 µg/kg. The detection rate was quite different in different fish species. The catfish devoted the highest detection rate which was 28.57%. In ten cities of Shaanxi, the highest detection rate was obtained from Yulin which was 33.33%. CONCLUSION: The health risk of intaking MG from freshwater fish is quite low for Shaanxi residents, however the contamination of illegal use of MG in freshwater fish was severe in Shaanxi Province. Supervision and inspection of MG should be strengthened in fish farming.