炎症因子TNF-α对人体皮肤细胞的影响以及有效提取物的筛选

本文首先以炎症因子TNF-α为刺激物作用于人体皮肤细胞,探究炎症因子对人体皮肤的影响。结果表明炎症因子TNF-α使得皮肤细胞内胶原蛋白含量表达异常,打破氧化还原系统影响人体皮肤,具有一定的加快皮肤老化作用,同时TNF-α可以作为刺激物建立慢性炎性皮肤衰老模型。后续实验通过TNF-α建立慢性炎性衰老模型,分别考察与比较维生素C、龙血竭提取物、铁皮石斛提取物对炎性衰老的抑制作用。结果表明,维生素C作为公认的抗衰老物质同样具有抑制炎性衰老功效;其次龙血竭提取物、铁皮石斛提取物同样具有一定的抑制炎性衰老功效。

Relationship between Shanghai Sand Junk Culture and the Development of Shanghai International Shipping Center

From the three aspects of material culture,institutional culture and spiritual culture,the connotation and development of Shanghai sand junk culture and the position in Shanghai shipping culture were analyzed,and the relationship between Shanghai sand junk culture and the development of Shanghai International Shipping Center was studied according to the construction target and the soft power demand of Shanghai International Shipping Center.

Research progress on preparation of cerium-based oxide catalysts with specific morphology and their application for purification of diesel engine exhaust

The elimination of pollutants from diesel exhaust has received widespread research attention as they cause serious air pollution and pose a threat to human health.Catalytic post-treatment technology is one of the most effective and universal technologies to treat diesel exhaust pollutants.The design and development of efficient and low-cost catalysts is the key factor to realize the wide application of catalytic post-treatment technology.Cerium(Ce)-based oxides with specific morphologies are widely used to eliminate pollutants in diesel vehicle exhaust due to their unique physical and chemical properties,such as high catalytic activity,low cost and non-toxicity.In this review,the preparation methods of Cebased oxide materials with specific morphologies,such as nanoparticles,nanocubes,nanorods,nanofibers,and multi-stage pores,are introduced in detail,and the research progress on using these catalysts for the removal of carbon monoxide,hydrocarbons,soot particles,nitrogen oxides,and other pollutants from diesel exhaust is reviewed in detail.Finally,the unresolved issues associated with using Ce-based oxide catalysts with a specific morphology to catalytically remove pollutants from diesel exhaust are highlighted,and future application prospects and development directions are discussed.

民族地区义务教育政策一致性量化评估与优化策略研究——以凉山彝族自治州为例

民族地区地方政府在公共政策制定中时常具备行使政策自由裁量权和充分落实中央重大战略决策的双重属性,其政策的“垂直化”和“弹性化”特质在我国中央和地方权力运行中具有特殊作用。本文以凉山彝族自治州义务教育政策为例,借助政策扩散理论的类型学分析框架详细考察了该地区义务教育政策文本的形成过程,并构建涵盖中央—省—州—市(县)四级行政体系的PMC指数模型,对该地区纵向义务教育政策文本的一致性水平进行了量化评价。研究发现:我国民族地区义务教育政策文本自上而下内部一致性分化明显,中央政策完备性明显强于地方;已出台的义务教育政策在促进义务教育质量方面积极效应不足,上下级政策间协同作用较弱。同时,民族自治州以下地方政府的政策透明性相对较弱,市县政府的义务教育政策层层照搬上级政策的现象较为明显。下一步应从政策细化、政策公开、政策协同、政策评价等方面进一步完善优化现行义务教育政策,及时构建政策清退机制。

Finding predictive models for singlet fission by machine learning

Singlet fission(SF),the conversion of one singlet exciton into two triplet excitons,could significantly enhance solar cell efficiency.Molecular crystals that undergo SF are scarce.Computational exploration may accelerate the discovery of SF materials.However,many-body perturbation theory(MBPT)calculations of the excitonic properties of molecular crystals are impractical for large-scale materials screening.We use the sure-independence-screening-and-sparsifying-operator(SISSO)machine-learning algorithm to generate computationally efficient models that can predict the MBPT thermodynamic driving force for SF for a dataset of 101 polycyclic aromatic hydrocarbons(PAH101).SISSO generates models by iteratively combining physical primary features.The best models are selected by linear regression with cross-validation.The SISSO models successfully predict the SF driving force with errors below 0.2 eV.Based on the cost,accuracy,and classification performance of SISSO models,we propose a hierarchical materials screening workflow.Three potential SF candidates are found in the PAH101 set.

Investigation of incipient faults in 66 kV oil-filled cable sealing ends

This paper reports on the investigation of incipient fault mechanisms of a widely used family of Cable Sealing Ends(CSEs)which use an earthed metallic clip on top of the stress cone to fasten the cable termination stress grading.Finite element simulations indicate that the clip is causing localised electric field enhancement which could also cause impurities in the oil to move towards the clip under the influence of the dielectrophoretic force.Accelerated ageing tests of stress cones in the laboratory have corroborated the simulation results,with the high electric field causing degradation of the semi-conducting tape underneath the clip as well as initiation of tracking on the surface of the stress cone originating from the edges of the clip.Partial discharge(PD)testing using a bespoke test rig in the high voltage laboratory has shown that incipient faults originating from the ageing of the solid CSE materials can only be detected after surface tracking has pro-gressed substantially.Even then,the intermittent nature of PD activity can pose a risk to the accurate condition assessment of CSEs if continuous monitoring is not employed and if the ultra-high frequency method is used on its own.