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Polymer-to-Monomers Chemically Recyclable Poly(imide-imine)Plastics with Extreme-Condition Resistance and Flame Retardancy

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Chinese Journal of Polymer Science 2024年第10期42卷 1525-1535,I0012页

作者： Zhen-Yu Wang xiao-kong Liu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun130012China

Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of ***,it is of great significance to develop recyclable polyimides with comparable properties to the commercial ***,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine *** PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial *** PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic ***,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame *** PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high *** recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.

关键词： Chemical recyclability Polyimides Polyimines Dynamic imine bonds Mechanical properties Chemical stability

Numerical manifold method for steady-state nonlinear heat conduction using Kirchhoff transformation

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Science China(Technological Sciences) 2024年第4期67卷 992-1006页

作者： ZHANG LiMei kong Heng ZHENG hong Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China Beijing Municipal Construction Co. Ltd.Beijing 100048China

The numerical manifold method(NMM)introduces the mathematical and physical cover to solve both continuum and discontinuum problems in a unified *** this study,the NMM for solving steady-state nonlinear heat conduction problems is presented,and heat conduction problems consider both convection and radiation boundary ***,the nonlinear governing equation of thermal conductivity,which is dependent on temperature,is transformed into the Laplace equation by introducing the Kirchhoff *** transformation reserves linearity of both the Dirichlet and the Neumann boundary conditions,but the Robin and radiation boundary conditions remain ***,the NMM is employed to solve the Laplace equation using a simple iteration procedure because the nonlinearity focuses on parts of the problem domain ***,the temperature field is retrieved through the inverse Kirchhoff *** examples are analyzed,demonstrating the advantages of the Kirchhoff transformation over the direct solution of nonlinear equations using the NewtonRaphson *** study provides a new method for calculating nonlinear heat conduction.

关键词： numerical manifold method nonlinear heat conduction temperature-dependent thermal conductivity Kirchhoff transformation convection and radiation boundary conditions

Mechanisms underlying the promotion of functional recovery by deferoxamine after spinal cord injury in rats

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Neural Regeneration Research 2017年第6期12卷 959-968页

作者： Jian Hao Bo Li Hui-quan Duan Chen-xi Zhao Yan Zhang Chao Sun Bin Pan Chang Liu xiao-hong kong Xue Yao Shi-qing Feng Department of Orthopedics Tianjin Medical University General Hospital School of Medicine Nankai University Tianjin Neurological Institute Key Laboratory of Post-Neuroinjury Neuro-Repair and Regeneration in Central Nervous System Ministry of Education

Deferoxamine, a clinically safe drug used for treating iron overload, also repairs spinal cord injury although the mechanism for this action remains unknown. Here, we determined whether deferoxamine was therapeutic in a rat model of spinal cord injury and explored potential mechanisms for this effect. Spinal cord injury was induced by impacting the spinal cord at the thoracic T10 vertebra level. One group of injured rats received deferoxamine, a second injured group received saline, and a third group was sham operated. Both 2 days and 2 weeks after spinal cord injury, total iron ion levels and protein expression levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin-1β and the pro-apoptotic protein caspase-3 in the spinal cords of the injured deferoxamine-treated rats were significantly lower than those in the injured saline-treated group. The percentage of the area positive for glial fibrillary acidic protein immunoreactivity and the number of terminal deoxynucleotidyl transferase d UTP nick end labeling-positive cells were also significantly decreased both 2 days and 2 weeks post injury, while the number of Neu N-positive cells and the percentage of the area positive for the oligodendrocyte marker CNPase were increased in the injured deferoxamine-treated rats. At 14–56 days post injury, hind limb motor function in the deferoxamine-treated rats was superior to that in the saline-treated rats. These results suggest that deferoxamine decreases total iron ion, tumor necrosis factor-α, interleukin-1β, and caspase-3 expression levels after spinal cord injury and inhibits apoptosis and glial scar formation to promote motor function recovery.

关键词： injured interleukin glial caspase saline underlying fibrillary minutes acidic neuronal

Al_(1-x)Sc_(x)Sb_(y)N_(1-y):An opportunity for ferroelectric semiconductor field effect transistor

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 133-140页

作者： Shujin Guo Xianghua kong hong Guo College of Physics and Electronic Engineering Center for Computational SciencesSichuan Normal UniversityChengdu 610068China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Physics McGill UniversityMontreal H3A 2T8Canada

For the in-memory computation architecture,a ferroelectric semiconductor field-effect transistor(FeSFET)incorporates ferroelectric material into the FET channel to realize logic and memory in a single *** emerging groupⅢnitride material Al_(1-x)Sc_(x)N provides an excellent platform to explore FeSFET,as this material has significant electric polarization,ferroelectric switching,and high carrier ***,steps need to be taken to reduce the large band gap of~5 eV of Al_(1-x)Sc_(x)N to improve its transport property for in-memory logic *** state-of-the-art first principles analysis,here we predict that alloying a relatively small amount(less than~5%)of Sb impurities into Al_(1-x)Sc_(x)N very effectively reduces the band gap while maintaining excellent *** show that the co-doped Sb and Sc act cooperatively to give a significant band bowing leading to a small band gap of~1.76 eV and a large polarization parameter~0.87 C/m^(2),in the quaternary Al_(1-x)Sc_(x)Sb_(y)N_(1-y)*** Sb impurity states become more continuous as a result of interactions with Sc and can be used for impurity-mediated *** on the Landau-Khalatnikov model,the Landau parameters and the corresponding ferroelectric hysteresis loops are obtained for the quaternary *** findings indicate that Al_(1-x)Sc_(x)Sb_(y)N_(1-y)is an excellent candidate as the channel material of FeSFET.

关键词： ferroelectricity Al_(1-x)Sc_(x)N FeSFET

The Role of HIV Replicative Fitness in Perinatal Transmission of HIV

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Virologica Sinica 2011年第3期26卷 147-155页

作者： Xue-qing Chen Chang Liu xiao-hong kong （Laboratory of Medical Molecular Virology School of Medicine Nankai University Tianjin 300071 China）

Perinatal transmission of Human immunodeficiency virus(HIV),also called mother-to-child transmission(MTCT),accounts for 90% of infections in infants worldwide and occurs in 30%-45% of children born to untreated HIV-1 infected *** HIV-1 infected mothers,some viruses are transmitted from mothers to their infants while others are *** relationship between virologic properties and the pathogenesis caused by HIV-1 remains *** studies have demonstrated that one obvious source of selective pressure in the perinatal transmission of HIV-1 is maternal neutralizing *** studies have shown that viruses which are successfully transmitted to the child have growth advantages over those not transmitted,when those two viruses are grown ***,the higher fitness is determined by the gp120 protein of the virus *** suggests that the selective transmission of viruses with higher fitness occurred exclusively,regardless of transmission *** are many factors contributing to the selective transmission and HIV replicative fitness is an important one that should not be *** review summarizes current knowledge of the role of HIV replicative fitness in HIV MTCT transmission and the determinants of viral fitness upon MTCT.

关键词： Human immunodeficiency virus(HIV) Acquired immune deficiency syndrome(AIDS) Mother-to-child transmission(MTCT) Replicative fitness Gp120

Liproxstatin-1 is an effective inhibitor of oligodendrocyte ferroptosis induced by inhibition of glutathione peroxidase 4

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Neural Regeneration Research 2021年第3期16卷 561-566页

作者： Bao-You Fan Yi-Lin Pang Wen-Xiang Li Chen-Xi Zhao Yan Zhang Xu Wang Guang-Zhi Ning xiao-hong kong Chang Liu Xue Yao Shi-Qing Feng International Cooperation Base of Spinal Cord Injury Tianjin Key Laboratory of Spine and Spinal CordDepartment of OrthopedicsTianjin Medical University General HospitalTianjinChina School of Medicine Nankai UniversityTianjinChina

Our previous studies showed that ferroptosis plays an important role in the acute and subacute stages of spinal cord *** intracellular iron levels and low glutathione levels make oligodendrocytes vulnerable to cell death after central nervous system *** this study,we established an oligodendrocyte(OLN-93 cell line)model of ferroptosis induced by RSL-3,an inhibitor of glutathione peroxidase 4(GPX4).RSL-3 significantly increased intracellular concentrations of reactive oxygen species and ***-3 also inhibited the main antiferroptosis pathway,i.e.,SLC7A11/glutathione/glutathione peroxidase 4(xCT/GSH/GPX4),and downregulated acyl-coenzyme A synthetase long chain family member ***,we evaluated the ability of several compounds to rescue oligodendrocytes from ***-1 was more potent than edaravone or ***-1 not only inhibited mitochondrial lipid peroxidation,but also restored the expression of GSH,GPX4 and ferroptosis suppressor protein *** findings suggest that GPX4 inhibition induces ferroptosis in oligodendrocytes,and that liproxstatin-1 is a potent inhibitor of ***,liproxstatin-1 may be a promising drug for the treatment of central nervous system diseases.

关键词： cell death central nervous system factor ferroptosis oligodendrocyte oxidation pathway repair spinal cord injury

Identification of key genes involved in recovery from spinal cord injury in adult zebrafish

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Neural Regeneration Research 2022年第6期17卷 1334-1342页

作者： Wen-Yuan Shen Xuan-Hao Fu Jun Cai Wen-Chang Li Bao-You Fan Yi-Lin Pang Chen-Xi Zhao Muhtidir Abula xiao-hong kong Xue Yao Shi-Qing Feng International Science and Technology Cooperation Base of Spinal Cord Injury Tianjin Key Laboratory of Spine and Spinal CordDepartment of OrthopedicsTianjin Medical University General HospitalTianjinChina Tianjin Medicine and Health Research Center Tianjin Institute of Medical&Pharmaceutical SciencesTianjinChina School of Medicine Nankai UniversityTianjinChina

Zebrafish are an effective vertebrate model to study the mechanisms underlying recovery after spinal cord *** subacute phase after spinal cord injury is critical to the recovery of neurological function,which involves tissue bridging and axon *** this study,we found that zebrafish spontaneously recovered 44%of their swimming ability within the subacute phase(2 weeks)after spinal cord *** this period,we identified 7762 differentially expressed genes in spinal cord tissue:2950 were up-regulated and 4812 were *** differentially expressed genes were primarily concentrated in the biological processes of the respiratory chain,axon regeneration,and cell-component *** genes were also mostly involved in the regulation of metabolic pathways,the cell cycle,and gene-regulation *** verified the gene expression of two differentially expressed genes,clasp2 up-regulation and h1m down-regulation,in zebrafish spinal cord tissue in *** enrichment analysis revealed that up-regulated clasp2 functions similarly to microtubule-associated protein,which is responsible for axon extension regulated by ***-regulated h1m controls endogenous stem cell differentiation after spinal cord *** study provides new candidate genes,clasp2 and h1m,as potential therapeutic intervention targets for spinal cord injury repair by *** experimental procedures and protocols were approved by the Animal Ethics Committee of Tianjin Institute of Medical&Pharmaceutical Sciences(approval ***-EAEP-Q-2019-02)on September 24,2019.

关键词： axon regeneration clasp2 endogenous neural stem cells h1m microtubule nanog neural regeneration neurogenesis spinal cord injury subacute phase

Unconventional Fluorescent and Multi-responsive Polysiloxane:Synthesis,Characterization and Biological Applications

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Chinese Journal of Polymer Science 2024年第5期42卷 579-590,I0006页

作者： xiao-Di Li Shu-Sheng Li Xu-Bao Jiang xiao-Li Zhu Xiang Zheng kong College of Chemistry and Chemical Engineering University of JinanJinan250022China College of Chemical Engineering Tianjin UniversityTianjin300072China Foshan(Southern China)Institute for New Materials Foshan528200China

Owing to their high significance in fundamental study and diverse applications,stimuli-responsive and fluorescent polymers,particularly those with cluster-triggered emission(CTE)featured by non-conjugated chromophores,have drawn tremendous attention in recent *** this work,fluorescent and multi-responsive polysiloxane(FRPS)was synthesized by hydrolytic condensation polymerization of 3-aminopropyl methyl diethoxysilane(APMS)with 3-(N-isopropyl propionamide)iminopropyl methyl diethoxysilane(APMS-NIP),which was formed in situ through aza-Michael addition between APMS and N-isopropyl *** was not only highly sensitive to temperature,pH and CO_(2) in water,but also showed an enhanced and stimuli-adjustable fluorescence *** effects of monomer feeding,pH and CO_(2) on its lower critical solution temperature and fluorescent property were *** fluorescence emission was ascribed to CTE *** addition,FRPS was shown to be highly potential as physiological indicator for cell imaging,and for controlled release and trace detection of *** study provides therefore a type of stimuli-responsive and fluorescent material for potential applications in biomedical fields,and it is also of great significance for understanding of the fluorescence mechanism of polysiloxane-based stimuli-responsive polymers.

关键词： Polysiloxane Multi-responsiveness Cluster-triggered emission Cell imaging Controlled drug release

MONOTONICITY CORRECTIONS FOR NINE-POINT SCHEME OF DIFFUSION EQUATIONS

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Journal of Computational Mathematics 2024年第5期42卷 1305-1327页

作者： Wang kong Zhenying hong Guangwei Yuan Zhiqiang Sheng School of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA) MIITNanjing 211106China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China

In this paper,we present a nonlinear correction technique to modify the nine-point scheme proposed in[SIAM ***.,30:3(2008),1341-1361]such that the resulted scheme preserves the *** first express the flux by the cell-centered unknowns and edge unknowns based on the stencil of the nine-point ***,we use a nonlinear combination technique to get a monotone *** order to obtain a cell-centered finite volume scheme,we need to use the cell-centered unknowns to locally approximate the auxiliary *** present a new method to approximate the auxiliary unknowns by using the idea of an improved multi-points flux *** numerical results show that the new proposed scheme is robust,can handle some distorted grids that some existing finite volume schemes could not handle,and has higher numerical accuracy than some existing positivity-preserving finite volume schemes.

关键词： Monotonicity corrections Diffusion equation Improved MPFA Distorted meshes