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ObjectiveTo establish a non-targeted screening method for emerging contaminants in drinking water based on high-resolution mass spectrometry and apply it to actual water samples. MethodsA total of 9 drinking water samples collected from 3 reservoirs in Shanghai were purified and concentrated by HLB solid phase extraction column， then separated and analyzed by liquid chromatography high-resolution mass spectrometer and gas chromatography high⁃resolution mass spectrometer. The acquired data were analyzed by Thermo Tracefinder， Excel and other software combined with mzCloud and NIST databases. The methodology was verified with representative compound standards. Pesticide and perfluorinated compounds were taken as examples to analyze their pollution status. ResultsA non-targeted analysis strategy based on liquid chromatography and gas chromatography tandem high-resolution mass spectrometry was established. The pollution level of 20 kinds of pesticides and 4 kinds of perfluorinated compounds identified in 9 drinking water samples were higher in the Huangpu River than in the Yangtze River estuary. ConclusionThe established non-targeted screening method by high-resolution mass spectrometry can detect potential emerging contaminants in drinking water without relying on the standards， which provides a powerful technical means for water quality monitoring and risk assessment.
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Per- and polyfluoroalkyl substances （PFASs） are a new type of persistent organic pollutants with global attention. They have shown multiple toxic effects due to their persistent accumulation in human body through exposure to environmental media such as drinking water， food， atmosphere， and soil. However， the bone toxicity of PFASs has not attracted enough attention. It is believed that the exposure and accumulation of PFASs in human have a significant impact on the bone health， especially hindering the healthy bone development in infants and adolescents， and aggravating the occurrence of bone loss and fracture in the elder populations. This paper will review the research progress of the effects of PFASs exposure on bone health indicators such as bone mineral density， and discuss the mechanisms of PFAS in bone toxicity. This review will provide references for revealing the effects of PFASs exposure on bone health and their toxic mechanisms.
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Background The production and consumption of high polar pesticides in China are the largest in the world. Therefore, it is urgent to develop a method with fast analysis, large flux, and high accuracy to determine the residues of these pesticides in food. Objective To establish a method for the determination of eight highly polar pesticides [chlormequat, paraquat, difenzoquat, cyromazine, propamocarb, glyphosate, (aminomethyl)-phosphonic acid, and glufosinate] in vegetables and fruits by ultra-performance liquid chromatography-tandem mass spectrometry. Methods After comparing various types of hydrophilic interaction liquid chromatography (HILIC) columns, and optimizing pH value and buffer concentration of mobile phase, effective chromatographic retention and separation of selected eight pesticides were achieved. Based on the optimization of mass spectrometry under chromatographic conditions, a multiple reaction monitoring (MRM) channel of target compounds was established. In the sample pretreatment, through optimization of water content, extraction solvent, and purification method, a final MRM mode of ultra-performance liquid chromatography-tandem mass spectrometry was used for detection, and the isotope internal standard method was used for quantification. The accuracy and the precision of the method were evaluated using recovery and relative standard deviation. The established method was applied to detect 57 samples of retail vegetables and fruits to investigate the adaptability of the proposed method and the residual levels of selected high polar pesticides. Results For positive ion electrospray ionization (ESI+) detection, we chose Sielc Obelisc R as chromatographic column, and 20 mmol·L−1 ammonium formate solution (pH=3±0.05) and acetonitrile as mobile phase; for negative ion electrospray ionization (ESI−) detection, we chose Shodex Asahipak NH2P-50 2D as chromatographic column, and 5 mmol·L−1 ammonium acetate solution (pH=11±0.05) and acetonitrile as mobile phase to obtain good chromatographic separation and peak shape. Under the optimal conditions of sample water content standardization, using 2% acidified methanol as extraction solvent, and C18 dispersed solid phase extraction purification, the linearity ranges of five analytes (chlormequat, paraquat, difenzoquat, cyromazine, and propamocarb) and three analytes [glyphosate, (aminomethyl)phosphonic acid, and glufosinate] were 1.00-100 μg·L−1 and 5.00-500 μg·L−1 (both correlation coefficients>0.999) respectively, the detection limits were 0.002-0.010 mg·kg−1, and the limits of quantification (LOQ) were 0.005-0.025 mg·kg−1. At three spiked levels (LOQ, 2LOQ, and 5LOQ), the recoveries were in the range of 85.3%–113.2%, and the relative standard deviations were 1.5%–9.5% (n=6). Three target pesticides (chlormequat, cyromazine, and propamocarb) were detected in 57 samples of retail vegetables and fruits, and the residue of chlormequat in cowpea exceeded the maximum residue limit. Conclusion The established method of HILIC combined with ultra-performance liquid chromatography-tandem mass spectrometry and isotopic internal standard quantification has the characteristics of simplicity, stability, and easy operation, which is suitable for rapid screening and quantitative detection of selected eight high polar pesticide residues in large quantities of vegetables and fruits, and provides technical support for monitoring and risk assessment of high polar pesticide residues.
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Objective To investigate the protective effect of menatetrenone (MK4) on the osteoblasts in oxidative stress, and to clarify the anti-osteoporosis mechanism of MK4. Methods Mouse osteoblasts (MC3T3-E1) induced by hydrogen peroxide (H2O2) was used. Cell viability, ALP activity and the area of bone nodule were observed. The level of ROS was detected by DCFH-DA, mitochondrial membrane potential by JC-1, apoptosis rate by annexin V-FITC/PI, and the expression of FoxO1, FoxO3, SOD, bcl-2 and bax by RT-PCR. Results Menatetrenone at 10 μmol/L significantly increased the proliferation of osteoblasts stimulated by H2O2, ALP activity, bone nodule formation area, cell membrane potential, the antioxidant SOD and transcription factors FoxO1 and FoxO3 mRNA expression. In the meantime, the elevated malondialdehyde and reactive oxygen species level in cells induced by H2O2, the apoptosis rate and the mRNA expression level of bax/Bcl-2 were significantly reduced. Conclusion menatetrenone can protect osteoblasts from oxidative damage by regulating FoxO pathway and reduce osteoblasts apoptosis by up regulating the proportion of Bcl-2/bax.
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Objective To compare the effects of vitamin K1 (VK1), vitamin K2 (MK4), vitamin K2 (MK7) and vitamin K3 (VK3) on bone formation and bone absorption. Methods Osteoblasts were isolated from calvaria of newborn rats and osteoclasts were induced by receptor activator of nuclear factor-κ B ligand (RANKL). ALP and TRAP activity were measured by diphenyl phosphate method. Osteoclast metabolic activity was measured by Celltiter kit. The inhibition of cathepsin K (CTSK) was measured by Z-FR-MCA fluorescent substrate and collagen substrate degradation. Results MK4 and MK7 at 0.1~1 μmol/L significantly increased the proliferation of osteoblasts (P<0.05) and at 1 μmol/L increased ALP activity and bone nodule formation area. VK3 inhibited bone nodule formation (P<0.05). VK1,VK3,MK4 and MK7 at 1 μmol/L had no effect on osteoclastic bone absorption. MK4 and MK7 significantly inhibited TRAP activity at 0.1~1 μmol/L (P<0.05), while VK1 and VK3 did not show the inhibitory effect. The inhibition of MK4 at 25 μmol/L on CTSK binding to Z-FR-MCA substrate activity is 58.9% and the inhibition of MK4 at 100 μmol/L on collagen degradation of CTSK activity is 73.2%. Conclusion Compared with VK1 and VK3, MK7 and MK4 significantly increase osteoblast activity and inhibit osteoclast bone absorption, MK4 inhibits osteoclast CTSK enzyme activity.
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Objective] To discuss the applicability of internal standard in determination of cycla-mate in wine by HPLC-tandem mass spectrometry . [ Methods] After dilution wine sample was deter-mined by HPLC-tandem mass spectrometry and quantified by external and internal standard methods respec-tively. [Results] The results by the 2 quantitation methods differed 11.2%in average, and the maxi-mum relative deviation was 16.2%.And the result by external standard quantitation method proved to be consistent with that by the international standard GB/T 5009.97-2003. [ Conclusion] The difference in results is thought to originate from matrix effect in HPLC-tandem mass spectrometry and the improper in-ternal standard compound applied .
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Objective To explore the biological functions of retinoic acid-inducible gene-I(RIG-I) in vivo through phenotype analysis of RIG-I knockout mice. Methods The gene expression of RIG-Ⅰ in various tissues of mice was examined with Northern blotting and semi-quantitative RT-PCR.The phenotypes observed included body weight measurement,differential count of peripheral blood cells,metabolic parameters measurement and histopathologic examination. ResultsRIG-Ⅰ expressed in various tissues of mice with different levels.No gross developmental abnormalities and expected maturation arrest in granulocytic differentiation were observed in RIG-Ⅰ knockout mice.However,RIG-Ⅰ knockout mice exhibited an unexpected increase in the ratios of neutrophiles to lymphocytes in peripheral blood and increased susceptibility to bacteria infection. Conclusion RIG-Ⅰ may play an important role in immune regulation in mice.
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Objective To analyze the stability of chromosome variant ratio of three available transformed corneal cell lines. Methods Chromosome specimens of transformed cells including human corneal epithelial cells(HCE),bovine corneal endothelial cells(BCE) and rabbit corneal epithelial cells(RCE) were prepared by a direct method using regular Giemsa staining. Chromosomes of cells in metaphase were counted under the microscope. Then, the variant ratio of chromosomes and their nuclear types were analyzed. Results The chromosome numbers were 56 to 65, 27 to 34 and 74 to 88 for HCE, BCE and RCE, respectively. Chromosome numbers in the three commonly used and transformed corneal cell lines were changed in comparison to their parent tissues. Conclusion Genotyping study may provide important information for using HCE、BCE、RCE in functional studies.