Microglial depletion impairs glial scar formation and aggravates inflammation partly by inhibiting STAT3 phosphorylation in astrocytes after spinal cord injury

Astrocytes and microglia play an orchestrated role following spinal cord injury;however,the molecular mechanisms through which microglia regulate astrocytes after spinal cord injury are not yet fully understood.Herein,microglia were pharmacologically depleted and the effects on the astrocytic response were examined.We further explored the potential mechanisms involving the signal transducers and activators of transcription 3(STAT3)pathway.For in vivo experiments,we constructed a contusion spinal cord injury model in C57BL/6 mice.To deplete microglia,all mice were treated with colony-stimulating factor 1 receptor inhibitor PLX3397,starting 2 weeks prior to surgery until they were sacrificed.Cell proliferation was examined by 5-ethynyl-2-deoxyuridine(EdU)and three pivotal inflammatory cytokines were detected by a specific Bio-Plex Pro^(TM) Reagent Kit.Locomotor function,neuroinflammation,astrocyte activation and phosphorylated STAT3(pSTAT3,a maker of activation of STAT3 signaling)levels were determined.For in vitro experiments,a microglia and astrocyte coculture system was established,and the small molecule STA21,which blocks STAT3 activation,was applied to investigate whether STAT3 signaling is involved in mediating astrocyte proliferation induced by microglia.PLX3397 administration disrupted glial scar formation,increased inflammatory spillover,induced diffuse tissue damage and impaired functional recovery after spinal cord injury.Microglial depletion markedly reduced EdU+proliferating cells,especially proliferating astrocytes at 7 days after spinal cord injury.RNA sequencing analysis showed that the JAK/STAT3 pathway was downregulated in mice treated with PLX3397.Double immunofluorescence staining confirmed that PLX3397 significantly decreased STAT3 expression in astrocytes.Importantly,in vitro coculture of astrocytes and microglia showed that microglia-induced astrocyte proliferation was abolished by STA21 administration.These findings suggest that microglial depletion impaired astrocyte proliferation and astrocytic scar formation,and induced inflammatory diffusion partly by inhibiting STAT3 phosphorylation in astrocytes following spinal cord injury.

Improved carrier injection and confinement in InGaN light-emitting diodes containing GaN/AlGaN/GaN triangular barriers

In this study, an InGaN lighting-emitting diode （LED） containing GaN/A1GaN/GaN triangular barriers is proposed and investigated numerically. The simulation results of output performance, carrier concentration, and radiative recombination rate indicate that the proposed LED has a higher output power and an internal quantum efficiency, and a lower efficiency droop than the LED containing conventional GaN or A1GaN barriers. These improvements mainly arise from the modified energy bands, which is evidenced by analyzing the LED energy band diagram and electrostatic field near the active region. The modified energy bands effectively improve carrier injection and confinement, which significantly reduces electron leakage and increases the rate of radiative recombination in the quantum wells.

Photodegradation of benzothiazole ionic liquids catalyzed by titanium dioxide and silver-loaded titanium dioxide

In recent years,ionic liquids(ILs)have been widely used in extraction,synthesis,electrochemistry and other fields.Meanwhile,the environmental impact of ILs has been attracting a lot of attention,and eco-friendly treatment for ILs is becoming a necessary subject.In this study,photocatalytic degradations of benzothiazole ILs catalyzed by titanium dioxide(TiO2)and silver-loaded titanium dioxide(Ag/TiO2)were studied for the first time.The degradation of benzothiazole hexafluorophosphate([C4 Bth]PF6)could reach more than 99%within 240 min with the catalysis of TiO2.To improve catalytic efficiency,Ag/TiO2 was synthesized and characterized by UV–Vis diffuse reflectance absorption spectra(DRS)and X-ray photoelectron spectroscopy(XPS).The degradation of[C4 Bth]PF6 could reach more than 99%within 120 min in the degradation catalyzed by Ag/TiO2.The photodegradation products of benzothiazole ILs are composed of inorganic substances or organic substances with simpler structures,which are easier to decompose and less toxic.The degradation system proposed by this study could provide a simple,green,safe,and economical method for the efficient treatment of benzothiazole ILs.

Exploring the Cultivation of Innovation and Entrepreneurial Abilities Among University Students Through the Construction of a Campus-based Green and Healthy Creative Workshop

This study aimed to provide a fresh approach for the cultivation of compound talents in the new era through a green and healthy creative workshop project,which is an integrated platform of innovation,entrepreneurship,learning,scientific research,and practice for both,undergraduates and postgraduates.The creative workshop was meticulously designed as an independent space,comprising of a front counter,a design area,an experience area,a physical therapy area,and an operational room.Various activities and creative products are made available within this confined space.It plays a useful role in promoting the development of a personnel training system for relevant disciplines,spreading excellent traditional medicine culture,and extending the educative and practical modes in Sichuan University.

对流层臭氧卫星遥感反演综述

臭氧是地球大气中最重要的痕量气体之一,在气候变化和生态环境中均扮演着至关重要的角色。对流层臭氧作为光化学烟雾的重要成分之一,其浓度变化与人类活动息息相关。基于卫星遥感技术监测对流层臭氧浓度可以帮助我们更好地发现和定量解释对流层臭氧在不同季节、不同时刻以及不同区域的变化特征,探讨臭氧在对流层中的成因机制。随着卫星遥感技术的全面发展,臭氧遥感产品(例如臭氧总量、廓线等)无论在产品精度或是时空分辨率方面均取得了显著进步,然而,由于受较弱卫星信号与复杂下垫面的影响,对流层臭氧遥感产品精度仍无法满足目前对流层大气成分的精细化科学应用研究。主要围绕对流层臭氧卫星遥感,回顾和分析了臭氧卫星遥感载荷的发展历程和现状,结果表明国内外已基于不同谱段(紫外—可见光、热红外和太赫兹)实现了全球及区域臭氧的时空分布探测;讨论了基于不同技术遥感反演算法(直接与间接反演、多波段联合反演、天底—临边协同反演、基于机器学习技术的创新算法等)的特点及适用性,分析表明算法精度的提升包括从复杂大气背景下的辐射传输模拟、基于地面观测的先验信息优化以及仪器定标与信噪比等多方面的工作;展望了卫星遥感在全球和区域尺度提供可靠对流层臭氧观测数据的应用前景,为对流层臭氧污染的形成机理、人类活动与气候变化如何影响对流层臭氧浓度变化等方面的研究提供关键数据支撑。

Oxidative stress-triggered Wnt signaling perturbation characterizes the tipping point of lung adeno-to-squamous transdifferentiation

Lkb1 deficiency confers the Kras-mutant lung cancer with strong plasticity and the potential for adeno-to-squamous transdifferentiation(AST).However,it remains largely unknown how Lkb1 deficiency dynamically regulates AST.Using the classical AST mouse model(Kras LSL-G12D/+;Lkb1flox/flox,KL),we here comprehensively analyze the temporal transcriptomic dynamics of lung tumors at different stages by dynamic network biomarker(DNB)and identify the tipping point at which the Wnt signaling is abruptly suppressed by the excessive accumulation of reactive oxygen species(ROS)through its downstream effector FOXO3A.Bidirectional genetic perturbation of the Wnt pathway using two different Ctnnb1 conditional knockout mouse strains confirms its essential role in the negative regulation of AST.Importantly,pharmacological activation of the Wnt pathway before but not after the tipping point inhibits squamous transdifferentiation,highlighting the irreversibility of AST after crossing the tipping point.Through comparative transcriptomic analyses of mouse and human tumors,we find that the lineage-specific transcription factors(TFs)of adenocarcinoma and squamous cell carcinoma form a“Yin-Yang”counteracting network.Interestingly,inactivation of the Wnt pathway preferentially suppresses the adenomatous lineage TF network and thus disrupts the“Yin-Yang”homeostasis to lean towards the squamous lineage,whereas ectopic expression of NKX2-1,an adenomatous lineage TF,significantly dampens such phenotypic transition accelerated by the Wnt pathway inactivation.The negative correlation between the Wnt pathway and AST is further observed in a large cohort of human lung adenosquamous carcinoma.Collectively,our study identifies the tipping point of AST and highlights an essential role of the ROS-Wnt axis in dynamically orchestrating the homeostasis between adeno-and squamous-specific TF networks at the AST tipping point.

Mo/Si原子高能量沉积中反射和再溅射的研究

使用分子动力学方法计算了Mo、Si原子发生反射和再溅射的概率,以及原子的反射、再溅射角度和能量分布。考虑了四种碰撞:Mo原子与Mo基底碰撞、Mo原子与Si基底碰撞、Si原子与Si基底碰撞、Si原子与Mo基底碰撞。模拟发现,当沉积原子传递给基底的能量降低时,发生反射的概率增加,但是发生再溅射的概率降低。此外,入射角度对反射概率、再溅射概率的影响与沉积原子和基底原子的种类有关;然而,入射能量越高越容易发生反射、再溅射。最后,进行了磁控溅射实验,在具有不同倾斜角度的基底上制备了Mo/Si多层膜样片,实验结论验证了仿真结果。研究结果可以用于模拟磁控溅射镀膜过程,优化镀膜工艺。

Enhancement of the mechanical properties of polylactic acid/basalt fiber composites via in-situ assembling silica nanospheres on the interface

A valid strategy to tailor the properties of polylactic acid for more extensive applications was introducing filler.In this work,basalt fiber assembled with in-situ SiO_(2) nanoparticles on the surface was successfully prepared via hydrothermal method and it was further treated with coupling agent KH-550 to improve interfacial interaction between polylactic acid(PLA)and basalt fibers(BF).It was demonstrated that the introduction of BFS could increase the crystallization of PLA and resulted in forming trans-crystallization based on TG and DSC results.The tensile strength of PLA/BF composites raised from 39 MPa to 62.5 MPa with increasing the fiber loading from 1 wt%to 10 wt%.Furthermore,the interfacial interaction could be effectively improved by assembling SiO_(2)(especially with 250 nm in diameter)on BF surface to build mechanical locking,which could keep the PLA matrix in place during the mechanical deformation with the tensile strength value raised from 62.5 MPa to 74.0 MPa.It is noticeable that the impact and flexural properties were effectively increased with the incorporation of in-situ SiO_(2) nanoparticles.The further KH-550 treatment made a positive impact as well.For instance,the impact strength and flexural strength of the sample with SiO_(2) and KH-550 modification were improved to 22.49 k J/m^(2) and 146.83 MPa and it enhanced about 42.16%and 41.04%than those of neat PLA,respectively.Therefore,an efficient enhancement of mechanical performance was achieved and this concept of assembling in-situ SiO_(2) on silica-based fiber as a modifier was a novel and simple path to design the interfacial construction and properties of the polymer composites.

Effect of cross-section shape of rotating chute on particle movement and distribution at the throat of a bell-less top blast furnace

Rotating chutes are widely used to control the burden distribution and enhance the gas distribution in a blast furnace.The chute cross-section shape has a significant effect on the particle movement and distribution.Therefore,this study developed a three-dimensional model of a blast furnace top with rotating chute using the discrete element method.The effect of different chute shapes on the particle movement and radial burden distribution was then investigated.The results showed that the burden stream height at the chute discharge agrees well with the burden stream thickness at the burden surface.A semicircular chute had the largest main striking point,where the chute discharge joins the burden surface,and trapezoidal and rectangular chutes had successively smaller MSPs.The semicircular chute helped to obtain a uniform radial size distribution.The trapezoidal chute helped form an aggregated burden stream at low rotating speeds,while the rectangular shape chute achieved this at higher rotating speeds and different chute angles.

Influence of annealing temperatures on microstructure evolution and mechanical properties in a low-carbon steel

Quenching and partitioning (Q&P) heat treatments with different annealing temperatures and fixed initial quenching tem-peratures were applied to cold-rolled low-carbon steel with the initial microstructure of ferrite and pearlite, aiming to gain the same amount of austenite (preset value) before the partitioning stage. The chemical compositions of the material have been specially designed, containing 1.6 wt.% silicon and 0.8 wt.% aluminum to avoid the precipitation of carbides. The micro-structure evolution of the investigated steel was characterized using a dilatometer, an optical microscope, a scanning electron microscope (SEM), an X-ray diffractometer, an electron backscattered diffraction and transmission electron microscope. Consequently, the microstructure of all samples looks quite similar. At the same time, according to SEM micrographs and dilatometer data, there are competitive reactions in Q&P process, such as the precipitation of carbides, the transformation of bainite and the formation of secondary martensite. Thus, the measured austenite is less than the preset values. Mechanical properties of the material were detected by uniaxial tensile tests. The results indicate that the ultimate tensile strength of the four groups of samples is similar, but the total elongation has a significant downward tendency with the increase in annealing temperatures. After annealing at 840 ℃, the steel possesses great ultimate tensile strength of about 1200 MPa and optimum total elongation of about 20.37% with favorable products of strength and elongation of about 24.35 GPa%.

Effect of Jiaji electroacupuncture in transected rat spinal cord

We evaluated the effect of Jiaji electroacupuncture on cell proliferation and the expression of markers of endogenous neural stem cell activation after complete spinal cord transection. Female Wistar rats were assigned to 4 groups (n = 24 each): a sham-operated group, a control group, a Jiaji electroacupuncture group, and a Jiaji electroacupuncture preconditioning group. Motor function was significantly improved in the acupuncture groups compared to the control group at 7 and 14 d. Numbers of bromodeoxyuridine (BrdU)-, nestin-, and glial fibrillary acidic protein (GFAP)-positive cells were significantly greater in the acupuncture groups than in the controls at each time point. Expression of nestin and GFAP mRNA was significantly higher in the acupuncture groups than in the controls at each time point. Thus, Jiaji electroacupuncture and preconditioning may promote the proliferation of endogenous neural stem cells after spinal cord transection.

Efficient and mild cyclization procedures for the synthesis of novel 2-amino-4H-pyran derivatives with potential antitumor activity

A series of novel 2-amino-4H-pyran derivatives have been synthesized via a three-component reaction of α,β-unsaturated ketone derivatives, malononitrile, aldehydes in excellent yields, using DBU as a catalyst and ethanol as a cheap, safe, and environmentally benign solvent under mild conditions. Their antitumor activity was evaluated in three human tumor cell lines, including human colon cancer （HCT116）, human cervical cancer （Hela）. and non-small cell lung cancer （H1975）.

Engineered microneedles arrays for wound healing

Wound healing is the regenerative process of original skin structure after destructing by different damage sources.Due to their transdermal delivery capability and high specific surface area,microneedles arrays(MAs)have been recognized as encouraging biomaterials for wound healing.In this review,we have outlined the engineered MAs used for tissue regeneration and wound healing.Engineered MAs were first classified by design methodologies such as bionic design,intelligent-responsive design,actively-triggered design,matrix materials innovation,and composite smart design.Then,the MAs were divided into two categories based on the different loading substances:drug-loaded MAs and living component-loaded MAs.Finally,we have summed up the important elements of the preceding discussions and forecasted their future evolution.

Discrete element method study of solid descending and residence properties in COREX shaft furnace with center gas supply device

Solid descending and residence properties in COREX shaft furnace with a center gas supply device (CGSD) were studied using the discrete element method. Solid flow pattern, residence time distribution, and local solid residence time (SRT) were analyzed. Moreover, the effects of the rotation speed of screws, the radius, and height of CGSD were investigated. The results show that the solid flow is dominantly a plug flow in the shaft furnace with the CGSD. In the upper region of the shaft furnace for gas-solid reduction, uniform distribution of local SRT is observed, which is preferable to match the even gas distribution expected due to the CGSD and slots. For different rotation speeds of the screws, the distribution of solid flow patterns is similar. The averaged residence time, dispersed plug volume fraction, and dead volume fraction decrease with increasing the rotation speed of the screws. The radius of the CGSD affects the solid residence in the shaft furnace. Local SRT above the CGSD increases with the increase in the radius of CGSD, possibly leading to the formation of more agglomerates. Hence, the radius of CGSD should be chosen carefully. The height of CGSD has a minor effect on solid residence in the shaft furnace.

Particles migration behavior during laser keyhole welding of ZL101/TiB_2 composites

Particle redistribution occurred with the flow of pool fluid in laser welding aluminum composites. In order to investigate particle migration behavior, a numerical model was established on laser welding of ZL101-TiB2 composite. TiB2 migration coupling with fluid was realized. The volume-of-fluid （VOF） method was employed to track free fluid surfaces. The travel heat source was realized utilizing the workpiece mo- tion in place of heat source motion, which made the heat load stable. Melting and evaporation enthalpy, recoil force, surface tension and buoyancy were considered in this model. Through the calculation it showed that the simulated weld cross section shape and particle distribution were in good agreement with experimental results.

The complete mitochondrial genome of Oreta fuscopurpurea(Lepidoptera: Drepanidae) and its phylogenetic implications

In this study, the first complete mitochondrial genome（mitogenome） of lepidopteran family Drepanidae（superfamily Drepanoidea） was reported with the notes about its phylogenetic implications. The Oreta fuscopurpurea mitogenome is 15,564 bp in length, including 13 protein-coding genes, two ribosomal RNAs（lrRNA and srRNA）, 22 transfer RNAs and a non-coding control region（AT-rich region）, with a 79.6% A＋T content. The gene orientation and arrangement of the mitogenome are the same as other sequenced lepidopterans. All protein-coding genes usually start with the common ATN codon except for COI gene, which used CGA as the initial codon; eight PCGs use a typical stop codon of TAA, whereas the remaining PCGs use incomplete stop codon of T or TA. All tRNAs have the typical clover-leaf structure with the exception of t RNA^（Ser）（AGN）. The lrRNA and sr RNA genes are 1,409 bp and 778 bp in size respectively, with the former harboring one（TA）_（13） microsatellite-like repeat and an 17 bp insertion. The 20 intergenic spacers totaling of 184 bp and 8 overlapping sequences totaling of 25 bp are scattered throughout the whole mitogenome. The 526 bp AT-rich region contains some structures characteristic of lepidopterans, such as the motif ATAGA preceded by an 19 bp poly-T stretch, a tRNA-like and a sterm-loop structures. Phylogenetic analysis of the Oreta fuscopurpurea with other 47 insect species covering 20 lepidopteran families were conducted based on the sequence data of the 13 mitogenomic protein coding genes with maximum likelihood（ML） and Bayesian inference（BI） methods, and the results showed distinctly that the superfamily Drepanoidea was sister to the clade of（Bombycoidea, Lasiocampoidea） ＋（Noctuoidea, Geometroidea）.