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Porous MAX compound combines the advantages of metals and ceramics, and has great filtration application prospects in harsh environments. In this work, porous Ti3(Si,Al)C2 was prepared by reaction synthesis of elemental powders, and its cyclic oxidation resistance at 800 °C for 100 h was studied. The synthesized Ti3(Si,Al)C2 has the MAX phase purity above 99 vol% with the maximum aperture, open porosity and permeability of 5.3 μm, 42.9% and 16.27 m3·m−2·kPa−1·h−1, respectively. The oxidation kinetics of porous Ti3(Si,Al)C2 is divided into two stages, which includes the linear law for the initial period within the first 10 h and the parabolic law for the subsequent stable period with their oxidation rate constants of 1.37 × 10−2 h−1 and 4.76 × 10−4 h−1, respectively. The final oxide layer is composed of rutile TiO2 and Al3Ti5O2 phases. In the stable stage, the maximum aperture and open porosity remain nearly constant with slight linear reduction rates of 4.32 × 10−3 μm·h−1 and 5.58 × 10−2%·h−1, which are 2.1% and 3.6% of those in the initial stage, respectively. In the last oxidation procedure of 40 h, the permeability decreases by 2.8%, showing a high stability. The high-temperature oxidation process for porous Ti3(Si,Al)C2 maintains a high and stable permeability and enhances the filtration accuracy by 96.3%, which improves the filtration performance.

Background Gastric lavage (GL) is one of the most critical early therapies for acute paraquat (PQ) poisoning; however, details of the treatment protocol remain to be established. Methods A rapid quantitative method involving sodium dithionite testing was developed. It was validated for the determination of the PQ concentrations in gastric juice and eluate samples from a swine acute PQ poisoning model with early or delay GL, or without. The vital signs, laboratory testing, and PQ plasma concentrations were collected for therapeutic effect evaluation. Results The reaction conditions of the test were optimized for two types of samples. Early GL at one hour (H1) could improve the signs and symptoms after acute PQ poisoning at 24 hours (H24). In contrast, GL at 6 hours (H6) could only partially relieve the vital signs. The H1 GL group effectively reduced the peak of the plasma PQ concentration. In addition, the PQ concentrations in the plasma and the gastric juice were significantly decreased in both the GL groups as compared to the untreated group at H24. Moreover, there was no significant difference in the washing efficiencies calculated from the total eluates between the two GL groups. However, the washing efficiency of the first 10 L eluate is superior to that of the additional 10 L eluate. Conclusion GL only at early stage may it benefit PQ poisoning in an animal model. The currently used 20 L GL volume may need to be reduced in view of the low washing efficiency in the later 10 L eluate. The rapid quantitative method can be used for gastric juice sample and has a certain value for clinical GL practices.

Perinatal exposure to bisphenol A (BPA) contributes to neurological disorders in offspring, but the underlying mechanisms are still poorly understood. The abnormal release of neuroactive metabolites in the tryptophan (TRP) and dopamine (DA) pathways is considered to be closely associated with some disorders. Thus, in this study, TRP and DA pathways in adult female mouse offspring were investigated when the pregnant mice were given either vehicle or BPA (2, 10, or 100 μg/kg/d) from day 6 of gestation until weaning. Then, the serum and brain samples of offspring were collected at 3, 6 and 9 months, and 12 neuroactive metabolites in the TRP and DA pathways were detected. The results showed that, in the TRP pathway, TRP levels decreased, whereas kynurenine (KYN) levels and TRP turnover increased in the brain. In the serum, TRP, KYN and 5-hydroxytryptamine (5-HT) levels decreased significantly. For the DA pathway, DA and DA metabolites, including 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3-MT) and homovanillic acid (HVA), reduced significantly in the brain and serum. DA turnover decreased dramatically in the brain but enhanced in the serum. The disturbance of these two metabolic pathways might be one of the potential mechanisms of BPA-induced neuropsychiatric disorders.

Tryptophan (TRP) and dopamine (DA) pathways are of great importance for their related pathology and physiology. In the present study, a new reliable and sensitive analytical method was developed and validated for 12 neuroactive metabolites in TRP and DA pathways in mouse serum and brain by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS). The method exhibited good sensitivity as the lower limit of detections ranged from 0.10 to 0.50 ng/ml and the lower limit of quantifications ranged from 0.20 to 2.00 ng/ml by derivatization with dansyl chloride (DNS-Cl) following solid phase extraction (SPE) on C18 cartridges. Good linearity (R2 > 0.99), intra-day precision (

High-purity porous Ti3SiC2 with a porosity of 54.3% was prepared by reactive synthesis and its oxidation behavior was evaluated under air in the temperature range from 400 to 1000 °C. Thermogravimetric analysis and differential scanning calorimetry (TG-DSC), scanning electron microscope (SEM), X-ray diffractometometry (XRD), energy dispersive spectrometer (EDS), Raman spectrum, BET surface area analysis, and pore-parameter testing were applied to the studies of the oxidation kinetics, phase composition, micro morphology, and porous structure parameters of porous Ti3SiC2 before and after oxidation. The results showed that the formation of TiO2 oxidized products with different modifications was the primary factor influencing the oxidation resistance and structural stability of porous Ti3SiC2. Cracks were observed in the samples oxidized in the full temperature range of 400-1000 °C because of the growth stress and thermal stress. At 400-600 °C, anomalous oxidation with higher kinetics and the aberrant decrement in pore size and permeability were attributed to the occurrence of severe cracking caused by the formation of anatase TiO2. At raised temperatures over 600 °C, the cracking phenomena were alleviated by the formation of rutile TiO2, but the outward growth of the oxide scales detrimentally decreased the connectivity of porous Ti3SiC2.

An efficient [3+3] tandem reaction between 1-phenyl-3-methyl-5-pyrazolones and 2-(1-alkynyl)-2-alken-1-ones over a tertiary amine–squaramide catalyst is described. The pyran fused pyrazolone derivatives were successfully obtained in 53–88% yields and with 62–84% ee by this synthetic methodology. This methodology involves easily accessible starting material, mild condition, satisfied yields and ee values. Additionally, when enynes were used as the substrates for the [3+3] cascade reaction, isomerized target products could be obtained directly.

Porous FeSi intermetallic compound was prepared by reactive synthesis of elemental powders. The evolutions of phase composition, microstructure and pore structure of Fe–Si compacts during the synthesis procedure were investigated, as well as the corrosion resistivity of the porous material against sulfuric acid solution. The results show that the major phases are generated in the order of α-Fe, Fe3Si, η-Fe5Si3 and e-FeSi during the sintering process. The skeletons of Fe5Si3 and FeSi phases are formed successively, resulting in a large number of connected pores in the compact. The final synthesized porous compound has the FeSi phase purity of 95.4 wt%. The open porosity, maximum pore size and gas permeability of porous FeSi are 53.8%, 14.1 μm and 92.20 m3 m−2 kPa−1·h−1, respectively. The radial dimension variation ratio, pore size and permeability show the linear change regulation with the sintering temperature with the change rate constants being 1.51 × 10−2%·°C−1, 5.3 × 10−2 μm·°C−1, 1.45 × 10−1 m3·m−2·kPa−1·h−1·°C−1, respectively. The pore size and permeability show the linear change law with the initial Fe powder size with the change rate constants being 5.4 × 10−2 μm·μm−1 and 3.05 × 10−1 m3·m−2·kPa−1·h−1·μm−1, respectively. The corrosion kinetics of the synthesized porous FeSi compound in 160 g·L−1 sulfuric acid solution shows a characteristic of two stages with the average corrosion rates being 2.11 × 10−3%·h−1 and 1.18 × 10−4%·h−1, respectively, in which porous FeSi shows good pore structure and microstructure stability.

A method for the identification and quantification of bisphenol A and 12 bisphenol analogues in river water and sediment samples combining liquid-liquid extraction, precolumn derivatization, and ultra high-performance liquid chromatography coupled with tandem mass spectrometry was developed and validated. Analytes were extracted from the river water sample using a liquid-liquid extraction method. Dansyl chloride was selected as a derivatization reagent. Derivatization reaction conditions affecting production of the dansyl derivatives were tested and optimized. All the derivatized target compounds were well separated and eluted in 10 min. Dansyl chloride labeled compounds were analyzed using a high-resolution mass spectrometer with electrospray ionization in the positive mode, and the results were confirmed and quantified in the parallel reaction monitoring mode. The method validation results showed a satisfactory level of sensitivity. Linearity was assessed using matrix-matched standard calibration, and good correlation coefficients were obtained. The limits of quantification for the analytes ranged from 0.005 to 0.02 ng/mL in river water and from 0.15 to 0.80 ng/g in sediment. Good reproducibility of the method in terms of intra- and interday precision was achieved, yielding relative standard deviations of less than 10.1 and 11.6%, respectively. Finally, this method was successfully applied to the analysis of real samples.

Excessive metal exposure has been recognized as one of the detrimental factors for brain damage. However, the potential adverse effects induced by heavy metals on monoamine neurotransmitter pathways remains poorly understood. Our study aimed to investigate the possible association between metal exposure and neurotransmitter metabolism. By a cross-sectional investigation, 224 electroplating workers and 213 non-electroplating exposure workers were recruited in the exposure and control groups. Metal exposure levels were analyzed using inductively-coupled plasma mass spectrometry and monoamine neurotransmitter pathway metabolites were measured by ultra-performance liquid chromatography tandem mass spectrometry in human urine samples. Multivariate linear regression model was used to assess the dose-response relationships of urinary metals and neurotransmitter pathway metabolites. Significant dose-dependent trends of urinary vanadium quartiles with all metabolites were observed, and the trends demonstrated significance after multiple testing correction. It also showed that urinary chromium levels were significantly associated with decreased serotonin level and cadmium was positively associated with norepinephrine and epinephrine. In addition, arsenic was positively associated with tryptophan, serotonin, dopamine and norepinephrine. Iron was positively associated with increased homovanillic acid (HVA) and epinephrine while nickel was negatively associated with increased epinephrine levels. Zinc was positively related to tryptophan, kynurenin (KYN), 5-hydroxyindole acetic acid (5-HIAA), dopamine, HVA and norepinephrine. There was no significant association between urinary copper with any other metabolites after adjusting of multiple metal models. Metal exposure may be associated with neurotransmitter metabolism disturbances. The present work is expected to provide some support in the prevention and management of metal-associated neurological diseases.