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Hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect neurons from cardiac arrest-induced pyroptosis
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作者 Xiahong Tang Nan Zheng +8 位作者 Qingming Lin Yan You Zheng Gong Yangping Zhuang Jiali Wu Yu Wang Hanlin Huang Jun Ke Feng Chen 《Neural Regeneration Research》 SCIE CAS 2025年第4期1103-1123,共21页
Cardiac arrest can lead to severe neurological impairment as a result of inflammation,mitochondrial dysfunction,and post-cardiopulmonary resuscitation neurological damage.Hypoxic preconditioning has been shown to impr... Cardiac arrest can lead to severe neurological impairment as a result of inflammation,mitochondrial dysfunction,and post-cardiopulmonary resuscitation neurological damage.Hypoxic preconditioning has been shown to improve migration and survival of bone marrow–derived mesenchymal stem cells and reduce pyroptosis after cardiac arrest,but the specific mechanisms by which hypoxia-preconditioned bone marrow–derived mesenchymal stem cells protect against brain injury after cardiac arrest are unknown.To this end,we established an in vitro co-culture model of bone marrow–derived mesenchymal stem cells and oxygen–glucose deprived primary neurons and found that hypoxic preconditioning enhanced the protective effect of bone marrow stromal stem cells against neuronal pyroptosis,possibly through inhibition of the MAPK and nuclear factor κB pathways.Subsequently,we transplanted hypoxia-preconditioned bone marrow–derived mesenchymal stem cells into the lateral ventricle after the return of spontaneous circulation in an 8-minute cardiac arrest rat model induced by asphyxia.The results showed that hypoxia-preconditioned bone marrow–derived mesenchymal stem cells significantly reduced cardiac arrest–induced neuronal pyroptosis,oxidative stress,and mitochondrial damage,whereas knockdown of the liver isoform of phosphofructokinase in bone marrow–derived mesenchymal stem cells inhibited these effects.To conclude,hypoxia-preconditioned bone marrow–derived mesenchymal stem cells offer a promising therapeutic approach for neuronal injury following cardiac arrest,and their beneficial effects are potentially associated with increased expression of the liver isoform of phosphofructokinase following hypoxic preconditioning. 展开更多
关键词 bone marrow–derived mesenchymal stem cells cardiac arrest cardiac resuscitation hypoxic preconditioning liver isoform of phosphofructokinase mitochondria NEUROINFLAMMATION oxidative stress PYROPTOSIS reactive oxygen species
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Small extracellular vesicles from hypoxia-preconditioned bone marrow mesenchymal stem cells attenuate spinal cord injury via miR-146a-5p-mediated regulation of macrophage polarization 被引量:1
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作者 Zeyan Liang Zhelun Yang +5 位作者 Haishu Xie Jian Rao Xiongjie Xu Yike Lin Chunhua Wang Chunmei Chen 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第10期2259-2269,共11页
Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)... Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury. 展开更多
关键词 bone marrow mesenchymal stem cells hypoxia preconditioning interleukin-1 receptor-associated kinase 1 MACROPHAGES mesenchymal stem cells small extracellular vesicles spinal cord injury
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8周运动预适应增强脂肪干细胞治疗心肌梗死大鼠的效果
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作者 娄国 张敏 付常喜 《中国组织工程研究》 CAS 北大核心 2025年第7期1363-1370,共8页
背景:干细胞移植是心肌梗死的崭新疗法,然而梗死区域极其恶劣的微环境造成干细胞存活率低下并导致远期疗效甚微。运动预适应是一种通过运动诱导机体产生内源性保护效应的方式,可作为心脏康复预防与治疗的新策略。目的:评估运动预适应是... 背景:干细胞移植是心肌梗死的崭新疗法,然而梗死区域极其恶劣的微环境造成干细胞存活率低下并导致远期疗效甚微。运动预适应是一种通过运动诱导机体产生内源性保护效应的方式,可作为心脏康复预防与治疗的新策略。目的:评估运动预适应是否能够增强大鼠心肌梗死后脂肪干细胞移植的心脏保护效应,探讨血管生成在其中的作用机制。方法:6周龄雄性SD大鼠随机分为对照组、造模组、干细胞组以及干细胞运动组。利用冠状动脉闭塞术制作急性心肌梗死模型,对照组同期行假手术;干细胞运动组于造模前进行8周有氧运动,造模后30 min进行脂肪干细胞移植;干细胞组仅进行脂肪干细胞移植。干细胞移植后1 d和7 d,利用免疫印迹法测定心肌总Akt(t-Akt)、磷酸化Akt(p-Akt)、血管内皮生长因子(VEGF)、总内皮型一氧化氮合酶(t-eNOS)和磷酸化内皮型一氧化氮合酶(p-eNOS)蛋白表达量,计算p-Akt/t-Akt和p-eNOS/t-eNOS比值;4周后利用彩色多普勒超声诊断系统检测心脏结构与功能以及心肌血流量,TTC染色法检测心肌梗死面积,Masson染色法检测心肌间质胶原沉积,免疫荧光染色法测定心肌毛细血管密度,TUNEL染色法评估心肌细胞凋亡。结果与结论:(1)干细胞移植后4周:与对照组比较,造模组左心室缩短分数、左心室射血分数、心肌毛细血管密度和心肌血流量下降(P<0.05),心肌梗死面积、胶原容积分数和细胞凋亡增加(P<0.05);与造模组比较,干细胞组上述指标(除左心室缩短分数和左心室射血分数外)得到改善(P<0.05);与干细胞组比较,干细胞运动组以上各参数进一步改善(P<0.05)。(2)干细胞移植后1 d:与对照组比较,造模组t-Akt、p-Akt、VEGF、t-eNOS、p-eNOS蛋白表达量以及p-Akt/t-Akt、p-eNOS/t-eNOS比值均无显著性变化(P>0.05);与造模组比较,干细胞组上述指标均无显著性变化(P>0.05),干细胞运动组磷酸化p-Akt蛋白表达量以及p-Akt/t-Akt比值上调(P<0.05)。(3)干细胞移植后7 d:与对照组比较,造模组p-Akt、VEGF、p-eNOS蛋白表达量以及p-Akt/t-Akt、p-eNOS/t-eNOS比值下降(P<0.05);与造模组比较,干细胞组各参数均无显著性变化(P>0.05),干细胞运动组p-Akt、VEGF、p-eNOS蛋白表达量以及p-Akt/t-Akt、p-eNOS/t-eNOS比值升高(P<0.05)。结果表明:运动预适应可增强脂肪干细胞对心肌梗死大鼠心脏重塑的治疗效果,其机制与促进心肌血管生成并增加血流灌注有关。 展开更多
关键词 干细胞 脂肪干细胞 运动预适应 心肌梗死 血管生成 心脏重塑 血流灌注
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miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow-derived neural crest cells 被引量:1
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作者 Meng Cong Jing-Jing Hu +9 位作者 Yan Yu Xiao-Li Li Xiao-Ting Sun Li-Ting Wang Xia Wu Ling-Jie Zhu Xiao-Jia Yang Qian-Ru He Fei Ding Hai-Yan Shi 《Neural Regeneration Research》 SCIE CAS 2025年第1期277-290,共14页
Our previous study found that rat bone marrow–derived neural crest cells(acting as Schwann cell progenitors)have the potential to promote long-distance nerve repair.Cell-based therapy can enhance peripheral nerve rep... Our previous study found that rat bone marrow–derived neural crest cells(acting as Schwann cell progenitors)have the potential to promote long-distance nerve repair.Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication.Nevertheless,the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear.To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves,we collected conditioned culture medium from hypoxia-pretreated neural crest cells,and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation.The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells.We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells.Subsequently,to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons,we used a microfluidic axonal dissociation model of sensory neurons in vitro,and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons,which was greatly dependent on loaded miR-21-5p.Finally,we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb,as well as muscle tissue morphology of the hind limbs,were obviously restored.These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p.miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome.This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves,and also promotes the application of miR-21-5p in tissue engineering regeneration medicine. 展开更多
关键词 AXOTOMY cell-free therapy conditioned medium extracellular vesicles hypoxic preconditioning microRNA oxygen-glucose deprivation peripheral nerve injury Schwann cell precursors
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运动预处理联合骨髓间充质干细胞移植治疗大鼠心肌梗死 被引量:1
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作者 王治坤 白少玄 +1 位作者 赵伟 王晨宇 《中国组织工程研究》 CAS 北大核心 2025年第1期65-73,共9页
背景:干细胞疗法在改善心肌梗死后心脏重构方面具有广阔前景,但心肌微环境改变影响干细胞疗效。运动预处理类似于缺血预处理,能够对心肌产生保护作用。然而,运动预处理与干细胞移植联合作用的效果与机制鲜有关注。目的:观察运动预处理... 背景:干细胞疗法在改善心肌梗死后心脏重构方面具有广阔前景,但心肌微环境改变影响干细胞疗效。运动预处理类似于缺血预处理,能够对心肌产生保护作用。然而,运动预处理与干细胞移植联合作用的效果与机制鲜有关注。目的:观察运动预处理对心肌梗死大鼠骨髓间充质干细胞移植效果的影响,探讨局部炎症微环境在其中的作用机制。方法:80只雌性SD大鼠随机分为假手术组、模型组、移植组和联合组,每组20只。利用结扎冠状动脉左前降支的方法制作心肌梗死大鼠模型,假手术组仅穿线不结扎。移植组和联合组造模后于心肌内注射雄性大鼠来源骨髓间充质干细胞,此外,联合组在造模前还需进行8周跑台运动(即运动预处理)。干细胞移植后4周,采用递增负荷运动力竭实验测定运动能力,超声心动术测定心脏结构与功能,压力容积导管法检测左心室血液动力学,原位染色法进行心肌组织病理学观察并获取心肌胶原容积分数。干细胞移植后1,7 d和4周,采用定量反转录聚合酶链反应检测左心室促炎症因子(白细胞介素1β、白细胞介素6、肿瘤坏死因子α)、抗炎症因子(白细胞介素10)、Y染色体性别决定区和胚胎基因(心房钠尿肽、脑钠肽、β-肌球蛋白重链)m RNA表达量。结果与结论:(1)干细胞移植后4周:与假手术组比较,模型组运动能力、左心室射血分数降低(P <0.05);心肌梗死面积、心肌细胞横截面积、胶原容积分数增加(P <0.05);胚胎基因以及促炎因子m RNA表达量上调(P <0.05),白细胞介素10 m RNA表达量下调(P <0.05)。与模型组比较,移植组运动能力、左心室射血分数增加(P <0.05);心肌梗死面积、心肌细胞横截面积、胶原容积分数下降(P <0.05);胚胎基因以及促炎因子m RNA表达量下调(P <0.05),白细胞介素10 m RNA表达量无显著性变化(P> 0.05)。与移植组比较,联合组上述各指标均进一步改善(P<0.05)。(2)干细胞移植后1,7d:与移植组比较,联合组Y染色体性别决定区m RNA表达量升高(P<0.05)。(3)相关分析显示,白细胞介素1β、白细胞介素6(除移植后1 d)、肿瘤坏死因子α与Y染色体性别决定区m RNA表达量呈负相关(P <0.05),白细胞介素10与Y染色体性别决定区m RNA表达量呈正相关(P <0.05)。结果表明:运动预处理能够增强骨髓间充质干细胞移植治疗心肌梗死大鼠的效果,表现为心脏重构得到抑制、心功能进一步提升,其机制与心肌炎症微环境改善促进骨髓间充质干细胞滞留和存活有关。 展开更多
关键词 运动预处理 心肌梗死 骨髓间充质干细胞 心脏重构 炎症反应 微环境
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基于非结构四面体网格的三维模型瞬变电磁大尺度正演模拟
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作者 鲁凯亮 岳建华 +3 位作者 樊亚楠 李貅 周建美 齐彦福 《地球物理学报》 北大核心 2025年第1期327-341,共15页
大尺度瞬变电磁三维正演生成的系数矩阵阶数往往高达百万乃至千万级,使用传统数值方法几乎无法同时兼顾计算效率和内存消耗.本文使用重启多项式Krylov子空间技术,结合预处理共轭梯度法,实现了高效的大尺度瞬变电磁三维正演模拟.采用非... 大尺度瞬变电磁三维正演生成的系数矩阵阶数往往高达百万乃至千万级,使用传统数值方法几乎无法同时兼顾计算效率和内存消耗.本文使用重启多项式Krylov子空间技术,结合预处理共轭梯度法,实现了高效的大尺度瞬变电磁三维正演模拟.采用非结构四面体网格对空间离散,使用矢量有限元方法离散控制方程,将瞬变电磁法的阶跃响应表示为矩阵指数函数和一个列向量的乘积.采用重启多项式Krylov子空间技术求解矩阵指数函数,对于给定的重启Krylov子空间维度,利用残差停止准则可以计算任意时刻指定精度的电磁响应.本文方法不需要求解线性方程组,通过GPU(Graphic Processing Unit)并行技术与优化重启多项式Krylov子空间参数,可以显著提高计算效率.通过与其他数值方法对比,验证了本文算法的优势和准确性.最后通过数值算例,表明本文提出的方法完全可以实现超百万级的大尺度三维正演模拟. 展开更多
关键词 瞬变电磁 大尺度三维正演 非结构四面体 重启多项式Krylov子空间 预处理共轭梯度法
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Preconditioned BiCGSTAB algorithm and its applications to eddy current solutions 被引量:1
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作者 朱发熙 余海涛 胡敏强 《Journal of Southeast University(English Edition)》 EI CAS 2009年第3期362-366,共5页
A new favorable iterative algorithm named as PBiCGSTAB (preconditioned bi-conjugate gradient stabilized) algorithm is presented for solving large sparse complex systems. Based on the orthogonal list, the special tec... A new favorable iterative algorithm named as PBiCGSTAB (preconditioned bi-conjugate gradient stabilized) algorithm is presented for solving large sparse complex systems. Based on the orthogonal list, the special technique of only storing non-zero elements is carried out. The incomplete LU factorization without fill-ins is adopted to reduce the condition number of the coefficient matrix. The BiCGSTAB algorithm is extended from the real system to the complex system and it is used to solve the preconditioned complex linear equations. The locked-rotor state of a single-sided linear induction machine is simulated by the software programmed with the finite element method and the PBiCGSTAB algorithm. Then the results are compared with those from the commercial software ANSYS, showing the validation of the proposed software. The iterative steps required for the proposed algorithm are reduced to about one-third, when compared to the BiCG method, therefore the algorithm is fast. 展开更多
关键词 preconditioned bi-conjugate gradient stabilized BiCGSTAB algorithm incomplete LU decomposition orthogonal list finite dement method(FEM) eddy current
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A Preconditioned Multigrid Method for Efficient Simulation of Three-dimensional Compressible and Incompressible Flows 被引量:14
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作者 Han Zhonghua He Fei Song Wenping Qiao Zhide 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2007年第4期289-296,共8页
To develop an efficient and robust aerodynamic analysis method for numerical optimization designs of wing and complex configuration, a combination of matrix preconditioning and multigrid method is presented and invest... To develop an efficient and robust aerodynamic analysis method for numerical optimization designs of wing and complex configuration, a combination of matrix preconditioning and multigrid method is presented and investigated. The time derivatives of three-dimensional Navier-Stokes equations are preconditioned by Choi-Merkle preconditioning matrix that is originally designed for two-dimensional low Mach number viscous flows. An extension to three-dimensional viscous flow is implemented, and a method improving the convergence for transonic flow is proposed. The space discretizaition is performed by employing a finite-volume cell-centered scheme and using a central difference. The time marching is based on an explicit Rtmge-Kutta scheme proposed by Jameson. An efficient FAS multigrid method is used to accelerate the convergence to steady-state solutions. Viscous flows over ONERA M6 wing and M100 wing are numerically simulated with Mach numbers ranging from 0.010 to 0.839. The inviscid flow over the DLR-F4 wing-body configuration is also calculated to preliminarily examine the performance of the presented method for complex configuration. The computed results are compared with the experimental data and good agreement is achieved. It is shown that the presented method is efficient and robust for both compressible and incompressible flows and is very attractive for aerodynamic optimization designs of wing and complex configuration. 展开更多
关键词 Navier-Stokes equations preconditioning method multigrid method numerical simulation
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间断缺氧暴露提高急性高空缺氧小鼠缺氧耐力的初步研究
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作者 徐佳伶 毛国赟 +6 位作者 胡明睿 李林霞 吉耀轩 智娜 白雁清 白云刚 王云英 《空军军医大学学报》 2025年第1期52-56,共5页
目的探讨间断缺氧暴露对急性缺氧条件下动物的运动行为能力等方面的影响。方法选用40只6周龄雄性C57BL/6J小鼠,随机分为4组(n=10):C0组、CH组、H1组、H2组。7 d预适应后,对CH、H1、H2组进行2 h 5000 m急性缺氧暴露,检测焦虑、运动能力... 目的探讨间断缺氧暴露对急性缺氧条件下动物的运动行为能力等方面的影响。方法选用40只6周龄雄性C57BL/6J小鼠,随机分为4组(n=10):C0组、CH组、H1组、H2组。7 d预适应后,对CH、H1、H2组进行2 h 5000 m急性缺氧暴露,检测焦虑、运动能力及肌酸激酶(CK)与乳酸脱氢酶(LDH)活性。结果与C0组相比,急性高空缺氧导致CH组动物焦虑水平升高(P<0.05),运动的时间与距离下降(P<0.05),CK与LDH活性升高(P<0.05);与未进行预适应的CH组相比,缺氧预适应降低急性高空缺氧时小鼠焦虑程度,增加运动的时间与距离,CK与LDH活性下降(P<0.05)。结论缺氧预处理对急性高空缺氧在焦虑情绪的形成、运动耐力和心肌损伤等方面均有改善作用。 展开更多
关键词 缺氧预适应 急性缺氧 心肌 运动耐力 焦虑
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PRECONDITIONED GAUSS-SEIDEL TYPE ITERATIVE METHOD FOR SOLVING LINEAR SYSTEMS 被引量:3
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作者 程光辉 黄廷祝 成孝予 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第9期1275-1279,共5页
The preconditioned Gauss-Seidel type iterative method for solving linear systems, with the proper choice of the preconditioner, is presented. Convergence of the preconditioned method applied to Z-matrices is discussed... The preconditioned Gauss-Seidel type iterative method for solving linear systems, with the proper choice of the preconditioner, is presented. Convergence of the preconditioned method applied to Z-matrices is discussed. Also the optimal parameter is presented. Numerical results show that the proper choice of the preconditioner can lead to effective by the preconditioned Gauss-Seidel type iterative methods for solving linear systems. 展开更多
关键词 Gauss-Seidel method preconditioned iterative method Z-MATRIX
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Umbilical cord-derived mesenchymal stem cells preconditioned with isorhamnetin:potential therapy for burn wounds 被引量:3
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作者 Shazmeen Aslam Irfan Khan +2 位作者 Fatima Jameel Midhat Batool Zaidi Asmat Salim 《World Journal of Stem Cells》 SCIE 2020年第12期1652-1666,共15页
BACKGROUND Impaired wound healing can be associated with different pathological states.Burn wounds are the most common and detrimental injuries and remain a major health issue worldwide.Mesenchymal stem cells(MSCs)pos... BACKGROUND Impaired wound healing can be associated with different pathological states.Burn wounds are the most common and detrimental injuries and remain a major health issue worldwide.Mesenchymal stem cells(MSCs)possess the ability to regenerate tissues by secreting factors involved in promoting cell migration,proliferation and differentiation,while suppressing immune reactions.Preconditioning of MSCs with small molecules having cytoprotective properties can enhance the potential of these cells for their use in cell-based therapeutics.AIM To enhance the therapeutic potential of MSCs by preconditioning them with isorhamnetin for second degree burn wounds in rats.METHODS Human umbilical cord MSCs(hU-MSCs)were isolated and characterized by surface markers,CD105,vimentin and CD90.For preconditioning,hU-MSCs were treated with isorhamnetin after selection of the optimized concentration(5μmol/L)by cytotoxicity analysis.The migration potential of these MSCs was analyzed by the in vitro scratch assay.The healing potential of normal,and preconditioned hU-MSCs was compared by transplanting these MSCs in a rat model of a second degree burn wound.Normal,and preconditioned MSCs(IH+MSCs)were transplanted after 72 h of burn injury and observed for 2 wk.Histological and gene expression analyses were performed on day 7 and 14 after cell transplantation to determine complete wound healing.RESULTS The scratch assay analysis showed a significant reduction in the scratch area in the case of IH+MSCs compared to the normal untreated MSCs at 24 h,while complete closure of the scratch area was observed at 48 h.Histological analysis showed reduced inflammation,completely remodeled epidermis and dermis without scar formation and regeneration of hair follicles in the group that received IH+MSCs.Gene expression analysis was time dependent and more pronounced in the case of IH+MSCs.Interleukin(IL)-1β,IL-6 and Bcl-2 associated X genes showed significant downregulation,while transforming growth factorβ,vascular endothelial growth factor,Bcl-2 and matrix metallopeptidase 9 showed significant upregulation compared to the burn wound,showing increased angiogenesis and reduced inflammation and apoptosis.CONCLUSION Preconditioning of hU-MSCs with isorhamnetin decreases wound progression by reducing inflammation,and improving tissue architecture and wound healing.The study outcome is expected to lead to an improved cell-based therapeutic approach for burn wounds. 展开更多
关键词 Burn wound ISORHAMNETIN Mesenchymal stem cells PRECONDITIONING Wound healing Small molecule
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Extracellular vesicles from hypoxia-preconditioned mesenchymal stem cells alleviates myocardial injury by targeting thioredoxininteracting protein-mediated hypoxia-inducible factor-1αpathway 被引量:3
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作者 Cheng-Yu Mao Tian-Tian Zhang +5 位作者 Dong-Jiu Li En Zhou Yu-Qi Fan Qing He Chang-Qian Wang Jun-Feng Zhang 《World Journal of Stem Cells》 SCIE 2022年第2期183-199,共17页
BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from ... BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from normoxic(NC)-MSCs.However,the cardioprotective mechanisms of HP-EVs are not fully understood.AIM To explore the cardioprotective mechanism of EVs derived from HP MSCs.METHODS We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs(ADSCs)following hypoxia in vitro or MI in vivo,in order to improve the survival of cardiomyocytes(CMs)and restore cardiac function.The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays.MicroRNA(miRNA)sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs.The molecular mechanism of EVs in mediating thioredoxin-interacting protein(TXNIP)was verified by the dual-luciferase reporter assay.Co-immunoprecipitation,western blotting,and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha(HIF-1α)ubiquitination and degradation via the chromosomal region maintenance-1(CRM-1)-dependent nuclear transport pathway.RESULTS HP-EVs derived from MSCs reduced both infarct size(necrosis area)and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo.Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP,an oxidative stress-associated protein.We showed miRNA224-5p,the most upregulated miRNA in HP-EVs,directly combined the 3’untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury.Our results demonstrated that MI triggered TXNIP-mediated HIF-1αubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs,which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.CONCLUSION The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP. 展开更多
关键词 Extracellular vesicles Myocardial infarction Mesenchymal stem cells Hypoxia preconditioning Thioredoxin-interacting protein Hypoxia-inducible factor 1 alpha
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Researches on preconditioned wire arrayZpinches in Xi’an Jiaotong University 被引量:2
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作者 Jian Wu Yihan Lu +5 位作者 Fengju Sun Xiaofeng Jiang Zhiguo Wang Daoyuan Zhang Xingwen Li Aici Qiu 《Matter and Radiation at Extremes》 SCIE CAS 2019年第3期32-41,共10页
The dynamics of wire array Z pinches are greatly affected by the initial state of the wires,which can be preconditioned by a prepulse current.Recent advances in experimental research on preconditioned wire array Z pin... The dynamics of wire array Z pinches are greatly affected by the initial state of the wires,which can be preconditioned by a prepulse current.Recent advances in experimental research on preconditioned wire array Z pinches at Xi’an Jiaotong University are presented in this paper.Single-wire explosion experiments were carried out to check the state of the preconditioning and to obtain the current parameters needed for wire gasification.Double-wire explosion experiments were conducted to investigate the temporal evolution of the density distribution of the two gasified wires.Based on the results of these experiments,a double-pulse Z-pinch facility,Qin-1,in which a 10 kA prepulse current was coupled with the 0.8 MA main current was designed and constructed.Wire arrays of different wire materials,including silver and tungsten,can be preconditioned by the prepulse current to a gaseous state.Implosion of the two preconditioned aluminum wires exhibited no ablation and little trailing mass. 展开更多
关键词 state. preconditioned SILVER
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High-efciency improved symmetric successive over-relaxation preconditioned conjugate gradient method for solving large-scale finite element linear equations 被引量:1
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作者 李根 唐春安 李连崇 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2013年第10期1225-1236,共12页
Fast solving large-scale linear equations in the finite element analysis is a classical subject in computational mechanics. It is a key technique in computer aided engineering (CAE) and computer aided manufacturing ... Fast solving large-scale linear equations in the finite element analysis is a classical subject in computational mechanics. It is a key technique in computer aided engineering (CAE) and computer aided manufacturing (CAM). This paper presents a high-efficiency improved symmetric successive over-relaxation (ISSOR) preconditioned conjugate gradient (PCG) method, which maintains lelism consistent with the original form. Ideally, the by 50% as compared with the original algorithm. the convergence and inherent paralcomputation can It is suitable for be reduced nearly high-performance computing with its inherent basic high-efficiency operations. By comparing with the numerical results, it is shown that the proposed method has the best performance. 展开更多
关键词 improved preconditioned conjugate gradient (PCG) method conjugate gradient method large-scale linear equation finite element method
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Neurophenotyping of Zebrafish Larvae that Are Preconditioned with Anesthetic Agent 被引量:1
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作者 Julie L. Mustard Matthew A. Strope +2 位作者 Christopher S. Havey Lucy S. Wang Norbert W. Seidler 《Journal of Behavioral and Brain Science》 2016年第2期99-106,共8页
Anesthetics evoke a stress-response, upregulating heat shock genes. This neuroprotective response to proteotoxic stress represents preconditioning, a process by which neuronal tissue, previously exposed to anesthetics... Anesthetics evoke a stress-response, upregulating heat shock genes. This neuroprotective response to proteotoxic stress represents preconditioning, a process by which neuronal tissue, previously exposed to anesthetics, is protected against future insult. It presumes a sub-lethal injury, affecting protein unfolding. Our hypothesis is: preconditioning evokes molecular events that result in downstream changes that offer a selective advantage in terms of neuronal function. We focused on the neurobehavioral aspects which we neurophenotyped. Larval zebrafish were exposed to trifluoroethanol (TFE), an anesthetic mimetic, and tested for both individual and group behavioral markers of neuronal function. In bright/dark tests, we observed that TFE-exposed larvae spent more time in the dark area (typically an adult-like response) than control larvae. The response of TFE larvae to noise startle was directly opposite to that of controls. TFE larvae swam towards the source of the startle (into the bright zone), whereas control larvae swam away from the source of the startle (into the dark), typical of fear-response. The larvae also exhibited several differences in social behaviors, including synchronized schooling and shoaling behaviors. The TFE-group showed a greater number of synchronized events versus controls. The TFE-group also exhibited more shoaling events compared with controls. While the long-term effects have yet to be determined, these results shed light on the mechanism of anesthetic preconditioning. These complex zebrafish behaviors normally develop with age and therefore represent, in the TFE-exposed group, a pattern of accelerated maturation of neuronal function, which is the neurophenotype attributed to preconditioning. 展开更多
关键词 ZEBRAFISH ANESTHETICS PRECONDITIONING Neurophenotype TRIFLUOROETHANOL
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Preconditioned Iterative Methods for Algebraic Systems from Multiplicative Half-Quadratic Regularization Image Restorations 被引量:1
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作者 Michael K.Ng 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2010年第4期461-474,共14页
Image restoration is often solved by minimizing an energy function consisting of a data-fidelity term and a regularization term.A regularized convex term can usually preserve the image edges well in the restored image... Image restoration is often solved by minimizing an energy function consisting of a data-fidelity term and a regularization term.A regularized convex term can usually preserve the image edges well in the restored image.In this paper,we consider a class of convex and edge-preserving regularization functions,i.e.,multiplicative half-quadratic regularizations,and we use the Newton method to solve the correspondingly reduced systems of nonlinear equations.At each Newton iterate,the preconditioned conjugate gradient method,incorporated with a constraint preconditioner,is employed to solve the structured Newton equation that has a symmetric positive definite coefficient matrix. The eigenvalue bounds of the preconditioned matrix are deliberately derived,which can be used to estimate the convergence speed of the preconditioned conjugate gradient method.We use experimental results to demonstrate that this new approach is efficient, and the effect of image restoration is reasonably well. 展开更多
关键词 Edge-preserving image restoration multiplicative half-quadratic regularization Newton method preconditioned conjugate gradient method constraint preconditioner eigenvalue bounds
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The preconditioned conjugate gradient deconvolution method and its application
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作者 Xi Xiaoyu Liu Hong 《Applied Geophysics》 SCIE CSCD 2006年第3期156-162,共7页
The preconditioned conjugate gradient deconvolution method combines the realization of sparse deconvolution and the optimal preconditioned conjugate gradient method to invert to reflection coefficients. This method ca... The preconditioned conjugate gradient deconvolution method combines the realization of sparse deconvolution and the optimal preconditioned conjugate gradient method to invert to reflection coefficients. This method can enhance the frequency of seismic data processing and widen the valid frequency bandwidth. Considering the time-varying nature of seismic signals, we replace the constant wavelet with a multi-scale time-varying wavelet during deconvolution. Numerical tests show that this method can obtain good application results. 展开更多
关键词 preconditioned conjugate gradient DECONVOLUTION multi-scale time-varying wavelet and high frequency restoration
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Preconditioned method in parallel computation
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作者 Wu Ruichan Wei Jianing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第1期220-222,共3页
The grid equations in decomposed domain by parallel computation are soled, and a method of local orthogonalization to solve the large-scaled numerical computation is presented. It constructs preconditioned iteration m... The grid equations in decomposed domain by parallel computation are soled, and a method of local orthogonalization to solve the large-scaled numerical computation is presented. It constructs preconditioned iteration matrix by the combination of predigesting LU decomposition and local orthogonalization, and the convergence of solution is proved. Indicated from the example, this algorithm can increase the rate of computation efficiently and it is quite stable. 展开更多
关键词 grid equations parallel computation PRECONDITION LU decomposition local orthogonalization.
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A Preconditioned Gridless Method for Solving Euler Equations at Low Mach Numbers
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作者 曹骋 陈红全 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2015年第4期399-407,共9页
A preconditioned gridless method is developed for solving the Euler equations at low Mach numbers.The preconditioned system in a conservation form is obtained by multiplying apreconditioning matrix of the type of Weis... A preconditioned gridless method is developed for solving the Euler equations at low Mach numbers.The preconditioned system in a conservation form is obtained by multiplying apreconditioning matrix of the type of Weiss and Smith to the time derivative of the Euler equations,which are discretized using agridless technique wherein the physical domain is distributed by clouds of points.The implementation of the preconditioned gridless method is mainly based on the frame of the traditional gridless method without preconditioning,which may fail to converge for low Mach number simulations.Therefore,the modifications corresponding to the affected terms of preconditioning are mainly addressed.The numerical results show that the preconditioned gridless method still functions for compressible transonic flow simulations and additionally,for nearly incompressible flow simulations at low Mach numbers as well.The paper ends with the nearly incompressible flow over a multi-element airfoil,which demonstrates the ability of the method presented for treating flows over complicated geometries. 展开更多
关键词 gridless method PRECONDITIONING Euler equations cloud of points
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IMPROVED PRECONDITIONED CONJUGATE GRADIENT METHOD AND ITS APPLICATION IN F.E.A.FOR ENGINEERING
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作者 郑宏 葛修润 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1993年第4期371-380,共10页
In this paper two theorems with theoretical and practical significance are given in respect to the preconditioned conjugate gradient method (PCCG). The theorems discuss respectively the qualitative property of the ite... In this paper two theorems with theoretical and practical significance are given in respect to the preconditioned conjugate gradient method (PCCG). The theorems discuss respectively the qualitative property of the iterative solution and the construction principle of the iterative matrix. The authors put forward a new incompletely LU factorizing technique for non-M-matrix and the method of constructing the iterative matrix. This improved PCCG is used to calculate the ill-conditioned problems and large-scale three-dimensional finite element problems, and simultaneously contrasted with other methods. The abnormal phenomenon is analyzed when PCCG is used to solve the system of ill-conditioned equations, ft is shown that the method proposed in this paper is quite effective in solving the system of large-scale finite element equations and the system of ill-conditioned equations. 展开更多
关键词 preconditioned conjugate gradient method finite element ill-conditioned problems
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