The gut microbiome:implications for neurogenesis and neurological diseases

There is an increasing recognition of the strong links between the gut microbiome and the brain,and there is persuasive evidence that the gut microbiome plays a role in a variety of physiological processes in the central nervous system.This review summarizes findings that gut microbial composition alterations are linked to hippocampal neurogenesis,as well as the possible mechanisms of action;the existing literature suggests that microbiota influence neurogenic processes,which can result in neurological disorders.We consider this evidence from the perspectives of neuroinflammation,microbial-derived metabolites,neurotrophins,and neurotransmitters.Based on the existing research,we propose that the administration of probiotics can normalize the gut microbiome.This could therefore also represent a promising treatment strategy to counteract neurological impairment.

Research on the solid particle erosion wear of pipe steel for hydraulic fracturing based on experiments and numerical simulations

Erosion wear is a common failure mode in the oil and gas industry.In the hydraulic fracturing,the fracturing pipes are not only in high-pressure working environment,but also suffer from the impact of the high-speed solid particles in the fracturing fluid.Beneath such complex conditions,the vulnerable components of the pipe system are prone to perforation or even burst accidents,which has become one of the most serious risks at the fracturing site.Unfortunately,it is not yet fully understood the erosion mechanism of pipe steel for hydraulic fracturing.Therefore,this article provides a detailed analysis of the erosion behavior of fracturing pipes under complex working conditions based on experiments and numerical simulations.Firstly,we conducted erosion experiments on AISI 4135 steel for fracturing pipes to investigate the erosion characteristics of the material.The effects of impact angle,flow velocity and applied stress on erosion wear were comprehensively considered.Then a particle impact dynamic model of erosion wear was developed based on the experimental parameters,and the evolution process of particle erosion under different impact angles,impact velocities and applied stress was analyzed.By combining the erosion characteristics,the micro-structure of the eroded area,and the micro-mechanics of erosion damage,the erosion mechanism of pipe steel under fracturing conditions was studied in detail for the first time.Under high-pressure operating conditions,it was demonstrated through experiments and numerical simulations that the size of the micro-defects in the eroded area increased as the applied stress increased,resulting in more severe erosion wear of fracturing pipes.