PPAR-γactivation promotes xenogenic bioroot regeneration by attenuating the xenograft induced-oxidative stress

Xenogenic organ transplantation has been considered the most promising strategy in providing possible substitutes with the physiological function of the failing organs as well as solving the problem of insufficient donor sources.However,the xenograft,suffered from immune rejection and ischemia-reperfusion injury(IRI),causes massive reactive oxygen species(ROS)expression and the subsequent cell apoptosis,leading to the xenograft failure.Our previous study found a positive role of PPAR-γ in antiinflammation through its immunomodulation effects,which inspires us to apply PPAR-γ agonist rosiglitazone(RSG)to address survival issue of xenograft with the potential to eliminate the excessive ROS.In this study,xenogenic bioroot was constructed by wrapping the dental follicle cells(DFC)with porcine extracellular matrix(p ECM).The hydrogen peroxide(H_(2)O_(2))-induced DFC was pretreated with RSG to observe its protection on the damaged biological function.Immunoflourescence staining and transmission electron microscope were used to detect the intracellular ROS level.SD rat orthotopic transplantation model and superoxide dismutase 1(SOD1)knockout mice subcutaneous transplantation model were applied to explore the regenerative outcome of the xenograft.It showed that RSG pretreatment significantly reduced the adverse effects of H2O2on DFC with decreased intracellular ROS expression and alleviated mitochondrial damage.In vivo results confirmed RSG administration substantially enhanced the host’s antioxidant capacity with reduced osteoclasts formation and increased periodontal ligament-like tissue regeneration efficiency,maximumly maintaining the xenograft function.We considered that RSG preconditioning could preserve the biological properties of the transplanted stem cells under oxidative stress(OS)microenvironment and promote organ regeneration by attenuating the inflammatory reaction and OS injury.

Optimal design of nanofiltration system for surface water treatment

Both reverse osmosis(RO) and nanofiltration(NF) membranes have been increasingly used for water purification and desalination. However, the salt rejection of NF membranes is quite different from that of RO membranes,which makes a significant distinction in their process designs. This work started from the performance investigation of a single NF membrane element and then focused on the process design of the NF system for surface water treatment. In experimental tests, it was found that the observed rejection of the NF element becomes nearly constant when the concentrate flow is large enough, while the membrane flux of the NF element is quite stable regardless of the water flow across the membrane surface. These findings can be used to instruct the process design of the NF system for surface water treatment. In process design, a two-stage arrangement is sufficient for the NF system to reach the highest water recovery, while the RO system requires a three-stage arrangement.

当代美国教育中的批判种族理论研究

美国当代批判种族理论萌发于二十世纪八十年代的批判法学领域,旨在打破研究中的“色盲主义”倾向,以维护少数族群权利,促进族际公平正义。批判种族理论由进步学者引入教育领域后,为揭露、解释和挑战教育系统中的种族主义和针对少数族群的教育不公提供了一套概念工具、分析框架和教学策略,主要围绕课程内容、教学方法、成就评估、学校拨款等方面提出教育主张。当代美国教育中批判种族理论的重要影响主要体现在对种族压迫话语的理论化,对欧洲中心认识论的挑战和反故事等方法的应用。其主要局限性包括未能打破二元对立的中心话语范式,忽视差异复杂性的本质主义,反主流叙事分析缺乏客观性与可信度。未来教育中的批判种族理论需要更加紧密联系批判行动,更新批判方法,结成更广泛的联盟,从而在对抗种族主义和教育不公的斗争中发挥更加积极的作用。