No abstract

No abstract

Bisphenol A (BPA), a typical endocrine disruptor, is widely used as a key monomer in the packaging industry. Residual monomer can transfer from the package material to the food and thereby pose a risk to the health of the consumer, so determination of BPA migration is highly important for food safety control. In this study, a simple but sensitive electrochemiluminescence (ECL) biosensor, which combines the characteristics of high selectivity of an aptamer and high sensitivity of ECL, has been developed to detect BPA from package materials. The aptamer was immobilized on a gold electrode surface through Au-S interaction. The aptamer was then hybridized with complementary DNA (CDNA) to form double-stranded DNA (dsDNA). Ru(phen) can intercalate into the grooves of dsDNA and acts as an ECL indicator; high ECL intensity can therefore be detected from the electrode surface. In the presence of BPA, which can competitively bind with the aptamer owing to their high affinity, Ru(phen) is released from the electrode surface and the ECL of the system is decreased. The decreasing ECL signal has a linear relationship with BPA in the range of 0.1-100 pM with a detection limit of 0.076 pM. The developed biosensor has been applied to detect migration of BPA from different categories of canned drink with satisfactory results.

A three-dimensional multicomponent multiphase lattice Boltzmann model (LBM) is established to model the coupled two-phase and reactive transport phenomena in the cathode electrode of proton exchange membrane fuel cells. The gas diffusion layer (GDL) and microporous layer (MPL) are stochastically reconstructed with the inside dynamic distribution of oxygen and liquid water resolved, and the catalyst layer is simplified as a superthin layer to address the electrochemical reaction, which provides a clear description of the flooding effect on mass transport and performance. Different kinds of electrodes are reconstructed to determine the optimum porosity and structure design of the GDL and MPL by comparing the transport resistance and performance under the flooding condition. The simulation results show that gradient porosity GDL helps to increase the reactive area and average concentration under flooding. The presence of the MPL ensures the oxygen transport space and reaction area because liquid water cannot transport through micropores. Moreover, the MPL helps in the uniform distribution of oxygen for an efficient in-plane transport capacity. Crack and perforation structures can accelerate the water transport in the assembly. The systematic perforation design yields the best performance under flooding by separating the transport of liquid water and oxygen.

Losartan and tripterygium glucoside tablet (TGT) are often simultaneously used for reducing urine protein excretion in clinic. However, it is unknown whether there is potential herb-drug interaction between losartan and TGT. The aim of this study was to investigate their potential herb-drug interaction, and clarify the mechanism of the effect of TGT on the pharmacokinetics of losartan and its metabolite EXP3174 in rats. The plasma concentrations of losartan and EXP3174 were determined by LC-MS, and the main pharmacokinetic parameters were calculated. The C , t and AUC of losartan became larger after co-administration, while the C and AUC of EXP3174 became smaller, suggesting that TGT could influence the pharmacokinetics of losartan and EXP3174. The effects of TGT and its main components on the metabolic rate of losartan were further investigated in rat liver microsomes. Results indicated that TGT and its two main ingredients could decrease the metabolic rate of losartan. Therefore, it was speculated that TGT might increase the plasma concentration of losartan and decrease the concentration of EXP3174 by inhibiting the metabolism of losartan. The results could provide references for clinical medication guidance of losartan and TGT to avoid the occurrence of adverse reactions.