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ObjectiveTo investigate the levels of seven organophosphorus esters （OPEs） and six indicator polychlorinated biphenyls （PCBs） in pig liver from Hubei Province， the risk of exposure to OPEs and PCBs in Hubei residents through dietary intake of pig liver were assessed.MethodsA total of 51 pig liver samples were collected from Hubei Province in 2022. By isotope dilution method， OPEs and PCBs in pig liver samples were determined by ultra-high performance liquid chromatography tandem mass spectrometry （UPLC-MS/MS） and high resolution gas chromatography high resolution magnetic mass spectrometry （HRGC-HRMS）， respectively. The source of pollution was explored by analyzing the fingerprint characteristics. Based on the estimation dietary intake （EDI） and hazard index （HI） of Hubei residents， the risk of exposure to OPEs and PCBs through dietary intake of pig liver was assessed.ResultsThe levels of seven OPEs （∑7OPEs） in pig liver ranged from 15.6 to 262 ng/g， with an average of 89.7 ng/g （P50=88.4 ng/g）. The levels of six PCBs （∑6PCBs） ranged from 3.67 to 19.5 pg/g， with an average of 9.02 pg/g （P50=8.21 pg/g）. Tris （1，3-Dichloro-2-Propyl） Phosphate （TDCPP） and PCB 52 was the main characteristic pollutant of OPEs and PCBs in pig liver， respectively. Some OPEs were positively correlated with each other （r=0.278-0.841， P

ObjectiveTo investigate the contamination levels of indicator polychlorinated biphenyls （PCBs） in pork in China and the dietary exposure and risks of Chinese residents.MethodsThe concentration of seven indicator PCBs （PCB 28， PCB 52， PCB 101， PCB 118， PCB 138， PCB 153， and PCB 180） in 203 pork samples from 13 provinces （autonomous regions， centrally administered municipality） in China in 2020 as monitoring sites were analyzed by combined isotope dilution-gas chromatography-high resolution mass spectrometry. The health risk of the population exposure of indicator PCBs through pork was assessed in conjunction with date on pork consumption in each province.ResultsThe mean concentrations of the seven indicator PCBs （∑7PCBs） in pork ranged from 0.053 （Guangxi） to 0.826 ng/g fat （Zhejiang）， and P95 concentrations ranged from 0.091 （Guangxi） to 2.702 ng/g fat （Zhejiang）. PCB 28 and PCB 52 were the main fingerprint features. The mean and P95 levels of ∑7PCBs ingested daily by Chinese residents through pork consumption were 0.062±0.076 （ng/kg·BW） and 0.158±0.207 （ng/kg·BW）， respectively， and the exposure risk index （ERI） was less than 1.ConclusionThe contamination level of ∑7PCBs in pork in China， as well as the health risk of residents exposed to indicator PCBs through a pork diet was low.

Clinically, pentothal sodium has been widely used for primary and general anesthesia induction. Also, it has been used to effectively inhibit convulsion. Pentothal sodium has a strong inhibitory effect on the respiratory center, excessive drug administration, and rapid dose rate that cause death of experimental animals on the respiratory depression. This study used a modified pentothal sodium solution to investigate its anesthetic effect. The pentothal sodium solution was modified based on pentothal sodium upon additions of magnesium sulfate, propylene glycol, and pure ethanol. The anesthetic effect of the modified pentothal sodium on Sprague–Dawley (SD) rats was investigated by comparing traditional pentothal sodium and ketamine; 60 SD rats were randomly divided into three groups. Each group was treated with traditional pentothal sodium, modified pentothal sodium, or ketamine, respectively, via intraperitoneal injection. The symptoms of experimental rats were observed, and onset time and anesthetic time were both recorded. The data were analyzed using statistical software. There were no significant differences in onset time and anesthetic time between the three groups. The variation of onset time and anesthetic time of the group treated with modified pentothal sodium was shorter than that of the other two groups. Furthermore, the number of anesthetic rats after the first injection was significantly higher than that of the other two groups. The modified pentothal sodium is capable of providing a stable anesthetic effect. The function and effect are much better than traditional pentothal sodium and ketamine.

ObjectiveTo measure perfluoroalkyl and polyfluoroalkyl substances （PFASs） in cord blood of newborns in Henan province and explore influencing factors of PFASs exposure.MethodsThe present study was based on the birth cohort established in Henan Province from 2013 to 2015. The levels of 11 PFASs in cord blood samples （n＝336） were detected. Generalized linear regression was used to analyze the effects of maternal socio­demographic characteristics， life style and dietary intake on the level of PFASs in umbilical blood of newborns.ResultsThe newborns of older mothers （GM ratio 1.03-1.05）， higher average monthly family income （GM ratio 1.30-1.63）， pregnancy smoking （GM ratio 2.90， 95% CI：1.11， 7.56） and passive smoking （GM ratio 1.84， 95%CI： 1.02， 3.32） tend to show higher PFAS exposure in cord blood. Newborns whose mothers worked during pregnancy （GM ratio 0.82， 95%CI：0.67，1.00）， and with multiparous mothers （GM ratio 0.65， 95% CI： 0.51， 0.82） had lower concentrations of PFASs. Mothers who had higher intake frequency of beef or mutton， pumpkin， garlic seedlings and pickles during pregnancy tend to have increased concentrations of PFASs in cord blood （GM ratio was 1.33-1.80）， while the concentration was lower during mothers who consumed more oranges， milk， cabbage and eggplant during pregnancy （GM ratio was 0.68-0.82）.ConclusionMaternal age， family income， history of smoke and passively smoke during pregnancy， parity， frequency of beef or mutton， and plant­based foods intake may affect PFASs exposure of newborns.

ObjectiveTo prepare reference materials of dioxins and dioxin-like polychlorinated biphenyls in fish powder matrix.MethodsUsing fly ash to feed grass carp, the fish samples were peeled, homogenized, dried, packed and sterilized. After homogeneity and stability studies, coordinated values were determined by 8 laboratories, and the uncertainty was evaluated.ResultsThe reference material had good uniformity and the stability was more than 12 months. The characteristic values of PCDD/Fs were 0.017-1.4 pg/g, the expanded uncertainty were 0.02-0.6 pg/g and the characteristic values of DL-PCBs were 0.54-16 pg/g, expanded uncertainty were 0.28-6 pg/g. The matrix reference material was approved by the evaluation committee(GBW(E)100741).ConclusionThe matrix reference material has good homogeneity and stability, which can be used in the quality control for analyzing, laboratory ability verification, analytical instrument calibration, analysis method accuracy evaluation and verification, etc.

Hydrodynamic regulation is an important measure to control black and malodorous water bodies and create a good water environment and water ecology.For tidal river network areas,the key to the treatment of water environment problems is to control the hydrodynamics of gates and pumping stations to achieve running water circulation.This paper simulates the hydrodynamic dispatching of the water quality maintenance of the water system in the tidal river network area of Fuzhou.A hydrodynamic water quality model based on the Environmental Fluid Dynamics Code (EFDC) is constructed for the complex river network of Fuzhou to simulate the influence of gate and pump dispatching under different water quality goals and diversion conditions in the study area on changes in water quality of river channels.According to the simulations of the model,it is concluded that the use of tidal range for diversion can reduce the operation and maintenance costs but cannot maintain the water quality at an excellent level.The use of pumping stations for diversion can rapidly restore the water quality of river channels,but pumping stations in different locations can lead to different effects on the water quality,and thus adjustment is required according to the actual operation and maintenance goals.The simultaneous opening of the gates on the south side of the water system and the pumping stations can easily cause reciprocating flow of water in the central area of the river network and result in water body turbulence,which is not conducive to the restoration and maintenance of water quality.Therefore,they should not be opened at the same time during operation.The conclusions of this paper can provide references for the implementation of water quality maintenance and hydrodynamic control in tidal river network areas.

A nano-composite coating was developed by adding nano-SiO2 to a home-made Waterborne fluorine-containing epoxy resin. The surface hydrophlicity of the coating was investigated by the contact angle with water. As the particle sizes of SiO2 changed from 7-18nm, the water contact angle of the films changed from 62.8° to 85.6°. The surface energy of the coating was calculated out through measuring the contact angles of the coating with water and 1-bromonaphthalene. The presence of SiO2 significantly enhanced the corrosion resistance of the composite coatings, which showed two times than that of the neat waterborne fluorine-containing epoxy coatings. And the thermos dynamic stability of the composite coatings has been significantly improved. When the silica content is 2.0%, the coating has the largest contact angle. Other performance of the coating was investigated in terms of their thickness, flexibility, pencil hardness, impact resistance.

The expression and properties of Green's function for a class of nonlinear fractional differential equations with integral boundary conditions are studied and employed to obtain some results on the existence of positive solutions by using fixed point theorem in cones. The proofs are based on the reduction of the problem considered to the equivalent Fredholm integral equation of the second kind. The results significantly extend and improve many known results even for integer-order cases.