[Determination of four phenolic endocrine-disrupting chemicals in water by dispersive solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry based on metal-organic skeleton porous carbon materials].

Phenolic endocrine-disrupting chemicals (EDCs) are exogenous substances that interfere with the endocrine system and disrupt normal cell functions upon entering a living organism, leading to reproductive and developmental toxicity. Therefore, the development of a rapid and efficient analytical method for detecting phenolic EDCs in environmental waters is crucial. Owing to the low concentration of phenolic EDCs in environmental water, appropriate sample pretreatment methods are necessary to remove interferences caused by the sample matrix and enrich the target analytes before instrumental analysis. Dispersive solid-phase extraction (DSPE) has gained considerable attention as a simple and rapid sample pretreatment method for environmental-sample analysis. In this method, an adsorbent material is uniformly dispersed in a sample solution and the target analytes are extracted through processes such as vortexing. Compared with traditional solid-phase extraction (SPE), DSPE increases the contact area between the adsorbent and sample solution, reduces the required amounts of adsorbent and organic solvents, and improves the extraction efficiency. The adsorbent material plays a critical role in DSPE because it determines the extraction efficiency of the method. Metal-organic frameworks (MOFs) are porous framework materials composed of metal clusters and multifunctional organic ligands. They possess many excellent properties such as tunable pore sizes, large surface areas, and good thermal and chemical stability, rendering them ideal adsorbent materials for sample pretreatment. MOF-derived porous carbon materials obtained through high-temperature carbonization not only increase the density of MOF materials for better separation but also retain the advantages of a large surface area, highly ordered porous structure, and high porosity. In this study, a porous carbon material derived from an MOF, named as University of Oslo-66-carbon (UiO-66-C), was synthesized using a solvothermal method and applied as an adsorbent to enrich four phenolic EDCs (bisphenol A, 4-tert-octylphenol, 4-nonylphenol, and nonylphenol) in water. A method combining DSPE with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established to analyze these phenolic EDCs in water. The UiO-66-C dosage, pH of water sample, adsorption time, eluent type and volume, elution time, and ion strength were optimized. Gradient elution was performed using methanol-water as the mobile phase. The target analytes were separated on an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm), and multiple reaction monitoring (MRM) was conducted in negative electrospray ionization mode. The method exhibited a linear correlation within the range of 0.5-100 µg/L for the four phenolic EDCs. The limits of detection (LODs) and quantification (LOQs) of the four phenolic EDCs were 0.01-0.13 µg/L and 0.03-0.42 µg/L, respectively. The precision of the method was evaluated through intra- and inter-day relative standard deviations (RSDs), with values ranging from 1.5% to 10.6% and from 6.1% to 13.2%, respectively. When applied to the detection of phenolic EDCs in tap and surface water, the spiked recoveries of the four phenolic EDCs were 77.1%-116.6%. Trace levels of 4-nonylphenol and nonylphenol were detected in surface water at levels of 1.38 and 0.26 µg/L, respectively. The proposed method exhibits good accuracy and precision; thus, it provides a new rapid, efficient, and sensitive approach for the detection of phenolic EDCs in environmental water.

Signaling pathways in brain ischemia: Mechanisms and therapeutic implications.

Ischemic stroke occurs when the arteries supplying blood to the brain are narrowed or blocked, inducing damage to brain tissue due to a lack of blood supply. One effective way to reduce brain damage and alleviate symptoms is to reopen blocked blood vessels in a timely manner and reduce neuronal damage. To achieve this, researchers have focused on identifying key cellular signaling pathways that can be targeted with drugs. These pathways include oxidative/nitrosative stress, excitatory amino acids and their receptors, inflammatory signaling molecules, metabolic pathways, ion channels, and other molecular events involved in stroke pathology. However, evidence suggests that solely focusing on protecting neurons may not yield satisfactory clinical results. Instead, researchers should consider the multifactorial and complex mechanisms underlying stroke pathology, including the interactions between different components of the neurovascular unit. Such an approach is more representative of the actual pathological process observed in clinical settings. This review summarizes recent research on the multiple molecular mechanisms and drug targets in ischemic stroke, as well as recent advances in novel therapeutic strategies. Finally, we discuss the challenges and future prospects of new strategies based on the biological characteristics of stroke.