上部锁紧式双层非线性扣件在南京地铁的应用效果分析

在南京地铁1号线双龙大道至南京南站地铁隧道正常运行的线路上,采用在线检测和锤击方法对比Ⅲ型减振器与上部锁紧式双层非线性减振扣件(GJ-32扣件)两种轨道结构形式下钢轨的垂向和横向频率响应特性。结果表明:GJ-32扣件相对于Ⅲ型减振器钢轨振动在200~400 Hz有较好的抑制作用;GJ-32扣件轨道结构形式具有较好的减振性能和阻尼特性;Ⅲ型减振器区间钢轨波磨发展严重,而GJ-32扣件十分有效地抑制了钢轨短波的增长。

Identification of microRNAs and messenger RNAs involved in human umbilical cord mesenchymal stem cell treatment of ischemic cerebral infarction using integrated bioinformatics analysis

In recent years,a large number of differentially expressed genes have been identified in human umbilical cord mesenchymal stem cell(hUMSC)transplants for the treatment of ischemic cerebral infarction.These genes are involved in various biochemical processes,but the role of microRNAs(miRNAs)in this process is still unclear.From the Gene Expression Omnibus(GEO)database,we downloaded two microarray datasets for GSE78731(messenger RNA(mRNA)profile)and GSE97532(miRNA profile).The differentially expressed genes screened were compared between the hUMSC group and the middle cerebral artery occlusion group.Gene ontology enrichment and pathway enrichment analyses were subsequently conducted using the online Database for Annotation,Visualization,and Integrated Discovery.Identified genes were applied to perform weighted gene co-suppression analyses,to establish a weighted co-expression network model.Furthermore,the protein-protein interaction network for differentially expressed genes from turquoise modules was built using Cytoscape(version 3.40)and the most highly correlated subnetwork was extracted from the protein-protein interaction network using the MCODE plugin.The predicted target genes for differentially expressed miRNAs were also identified using the online database starBase v3.0.A total of 3698 differentially expressed genes were identified.Gene ontology analysis demonstrated that differentially expressed genes that are related to hUMSC treatment of ischemic cerebral infarction are involved in endocytosis and inflammatory responses.We identified 12 differentially expressed miRNAs in middle cerebral artery occlusion rats after hUMSC treatment,and these differentially expressed miRNAs were mainly involved in signaling in inflammatory pathways,such as in the regulation of neutrophil migration.In conclusion,we have identified a number of differentially expressed genes and differentially expressed mRNAs,miRNA-mRNAs,and signaling pathways involved in the hUMSC treatment of ischemic cerebral infarction.Bioinformatics and interaction analyses can provide novel clues for further research into hUMSC treatment of ischemic cerebral infarction.

高架城市轨道交通车辆及桥梁振动的理论研究

为研究高架轨道交通运行时的车辆与桥梁振动,以南京地铁1号线南延线某区间列车运行出现竖向振动异常为工程背景,对列车过桥引起的车桥振动状态进行了相关的理论分析,给出了车桥共振的条件,对车桥耦合振动进行了仿真模拟计算,并结合计算结果分析了不同影响因素对车桥振动的影响。通过综合各种分析,对过桥时列车的安全性、舒适性及桥梁结构的动力特性有了全面了解,并提出了相应的振动控制措施。

Molecular chaperones and hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy（HIE） is a disease that occurs when the brain is subjected to hypoxia,resulting in neuronal death and neurological deficits,with a poor prognosis.The mechanisms underlying hypoxic-ischemic brain injury include excitatory amino acid release,cellular proteolysis,reactive oxygen species generation,nitric oxide synthesis,and inflammation.The molecular and cellular changes in HIE include protein misfolding,aggregation,and destruction of organelles.The apoptotic pathways activated by ischemia and hypoxia include the mitochondrial pathway,the extrinsic Fas receptor pathway,and the endoplasmic reticulum stress-induced pathway.Numerous treatments for hypoxic-ischemic brain injury caused by HIE have been developed over the last half century.Hypothermia,xenon gas treatment,the use of melatonin and erythropoietin,and hypoxic-ischemic preconditioning have proven effective in HIE patients.Molecular chaperones are proteins ubiquitously present in both prokaryotes and eukaryotes.A large number of molecular chaperones are induced after brain ischemia and hypoxia,among which the heat shock proteins are the most important.Heat shock proteins not only maintain protein homeostasis; they also exert anti-apoptotic effects.Heat shock proteins maintain protein homeostasis by helping to transport proteins to their target destinations,assisting in the proper folding of newly synthesized polypeptides,regulating the degradation of misfolded proteins,inhibiting the aggregation of proteins,and by controlling the refolding of misfolded proteins.In addition,heat shock proteins exert anti-apoptotic effects by interacting with various signaling pathways to block the activation of downstream effectors in numerous apoptotic pathways,including the intrinsic pathway,the endoplasmic reticulum-stress mediated pathway and the extrinsic Fas receptor pathway.Molecular chaperones play a key role in neuroprotection in HIE.In this review,we provide an overview of the mechanisms of HIE and discuss the various treatment strategies.Given their critical role in the disease,molecular chaperones are promising therapeutic targets for HIE.

Probing surface interactions of underwater oleophobic polyelectrolyte multilayers

In the present work,the interaction mechanism of specific polyelectrolyte multilayers(PEMs),fabricated by layer-by-layer deposition of polydiallyldimethylammonium chloride(PDDA)and poly(sodium 4-styrenesulfonate)(PSS),is studied using atomic force microscopy.The underwater oil-repellency of PS S-capped PEMs was further explored by measuring the interaction forces between tetradecane droplets and PEMs-coated silica substrates under various salinities.The force curves were analyzed following the Stokes-Reynolds-Young-Laplace theoretical model.Desirable consistency was achieved between the experimental and theoretical calculations at low NaCl concentrations(0.1 mM and 1 mM);however,underestimation of the attractive force was found as the NaCl concentration increases to moderate(10 mM)and high(100 mM)levels.Discrepancy analyses and incorporated features toward a reduced surface charge density were considered based on the previous findings of the orientation of anionic benzenesulfonate moieties(Liu et al.in Angew Chem Int Ed 54(16):4851-4856,2015.https://doi.org/10.1002/anie.201411992).Short-range steric hindrance interactions were further introduced to simulate"brush"effect stemming from nanoscale surface roughness.It is demonstrated in our work that the PSS-capped PEMs remains a stable underwater lipophobicity against high salinity,which renders it potential application in surface wetting modification and anti-fouling.

扣件刚度对钢轨振动特性的影响研究

准确合理的扣件刚度参数对轨道结构设计至关重要,目前的研究尚未明确扣件刚度和钢轨振动特性之间的关系。依据单自由度隔振系统的计算公式,结合国内某地铁线路实测数据,重点研究现场钢轨垂向和横向的固有频率、振型和振动传递特性,有限元仿真和现场锤击测试充分验证了理论计算。在此基础上,通过钢轨整体的共振频率反演得到现场扣件的动刚度。该研究可为轨道减振器的仿真计算和优化设计提供依据。

Anti-inflammatory and Anti-oxidative Effects of the Ethanol Extract of Cryptocarya densiflora Blume in Lipopolysaccharide-Stimulated RAW264,7 Mouse Macrophages

CD （Cryptocarya densiflora） Blume has traditionally been used as an herbal medicine. In this study, the effects of CDEE （CD ethanol extract） on inflammation were investigated in LPS （lipopolysaccharide）-stimulated mouse RAW264.7 macrophages. We investigated the effects of CDEE on the production of NO, PGE2 interleukin （IL）-6, IL-1β, and tumor necrosis factor （TNF）-α in LPS-stimulated RAW264.7 cells. We measured the mRNA or protein expression of the pro-inflammatory mediators induced by CDEE in LPS-stimulated RAW264.7 cells. We explored the expression of Nrf-2, heme oxygenase （HO）-I and NADPH-quinone oxidoreductase （NQO）-I to elucidate the antioxidative mechanisms. CDEE significantly inhibited the production of NO, PGE2, IL-6, IL-1β and TNF-α in LPS-stimulated RAW264.7 cells. CDEE suppressed the mRNA or protein expression of iNOS, COX-2, and the MAPKs with a reduction in the translocation of NF-κB in LPS-stimulated RAW264.7 cells. In addition, CDEE significantly increased the expression of HO-I and NQO-1 with an increase in the translocation of Nrf-2 into the nucleus. These results indicate that CDEE inhibits the LPS-induced inflammatory and oxidative responses via suppression of NF-κB activation and the enhancement of Nrf2 activation. We suggest that CDEE may be therapeutic for treating inflammatory diseases.

Architecture design and advanced manufacturing of heart-on-a-chip:scaffolds,stimulation and sensors

Heart-on-a-chip(HoC)has emerged as a highly efficient,cost-effective device for the development of engineered cardiac tissue,facilitating high-throughput testing in drug development and clinical treatment.HoC is primarily used to create a biomimetic microphysiological environment conducive to fostering the maturation of cardiac tissue and to gather information regarding the real-time condition of cardiac tissue.The development of architectural design and advanced manufacturing for these“3S”components,scaffolds,stimulation,and sensors is essential for improving the maturity of cardiac tissue cultivated on-chip,as well as the precision and accuracy of tissue states.In this review,the typical structures and manufacturing technologies of the“3S”components are summarized.The design and manufacturing suggestions for each component are proposed.Furthermore,key challenges and future perspectives of HoC platforms with integrated“3S”components are discussed.

Increased globulin and its association with hemorrhagic transformation in patients receiving intra-arterial thrombolysis therapy

Previous studies have identified a diverse set of predisposing factors for the occurrence of hemorrhagic transformation （HT）, but the independent clinical predictors of HT after intra- arterial thrombolysis have not been determined. In this retrospective study, we investigated the characteristics of patients with or without HT who had received intra-arterial thrombolysis therapy, using biochemical analysis, renal function test, routine blood test, blood lipid test, coagulation blood test, liver function test, random blood glucose test, time- window for intra-arterial thrombolysis, recanalization, National Institutes of Health Stroke Scale （NIHSS） score and systolic blood pressure before intra-artedal thrombolysis. The mortality rates were similar in the HT and non-HT groups （P = 0.944）. In the single- factor analysis, patients with a higher globulin level （P 〈0.002）, prothrombin time activity percentage （PTA; P = 0.026）, and NIHSS score （P = 0.002）, had a significantly increased risk of developing HT. In the multifactor logistic regression model involving globulin level, PTA, white blood cell count, and NIHSS score, the globulin level （P 〈0.001; OR, 1.185; 95% confidence interval [CI], 1.090-1.288）, PTA （P = 0.018; OR, 1.016; 95% CI, 1.003-1.029）, white blood cell count （P = 0.025; OR, 1.097; 95% CI, 1.012-1.190） and NIHSS score （P = 0.003; OR, 1.097; 95% CI, 1.031-1.166） were significantly increased in the HT group. The increase in globulin level is an independent risk factor for HT in patients receiving intra-arterial thrombolysis. The possible mechanisms may involve inflammatory cytokines, matrix metalloproteinase 9, and positive acute-phase reactants synthesized by the liver.

具有高光热转化率和环境pH响应的载药硫化铜纳米粒子

采用铜离子与硫离子在溶液中直接反应制备粒径为50~60 nm的硫化铜纳米颗粒(CuS NPs).在CuS NPs表面修饰了聚多巴胺层,并利用聚多巴胺(PDA)的非共价键自聚在聚多巴胺层表面负载DOX,从而得到一种核壳结构纳米粒子——DOX@CuS/PDA(其核为CuS NPs,壳为担载阿霉素的聚多巴胺).研究表明,该硫化铜纳米颗粒具备光热敏感特性,在功率为1 W/cm^2的808 nm近红外光照射下,光热转化率高达34.2%.在不同pH下释放的研究结果表明,在酸性条件下经过72 h体外释放后,DOX@CuS/PDA累积DOX的释放量是其在碱性环境中的6倍,证明了DOX@CuS/PDA拥有明显的pH刺激响应释放机制.在体外癌细胞实验结果中,DOX@CuS/PDA可以将光热治疗与化学药物治疗相互结合,癌细胞存活率仅有27%~33%,有效地提升了肿瘤细胞灭杀效果.本研究对于光热治疗和化学治疗相结合提供了研究方案,并且对于吸附载药以及pH响应药物释放研究提供了新认识.

3D T1-weighted black blood sequence at 3.0 Tesla for the diagnosis of cervical artery dissection

Objective:We aimed to investigate the value of threedimensional(3D)T1 volumetric isotropic turbo spin echo acquisition(VISTA)in the diagnosis of cervical artery dissection(CAD).Methods:We prospectively included patients who were suspected as having a CAD within 1 month of onset.For T1 VISTA,the diagnosis of the dissection was based on the presence of intramural high-signal,intimal flap,double lumen and aneurysmal dilation.The final diagnosis of dissection was based on the clinical history,physical examination,and all of the imaging tests.Results:A total of 46 patients were included in this study.The final diagnosis of CAD was made for 21 patients.Diagnosis of dissection was made for 20 of the 21 patients after assessing T1 VISTA.A definitive diagnosis of dissection was not made for 5 patients(including 3 patients with digital subtraction angiography)before the T1 VISTA examination.The sensitivity and specificity for T1 VISTA were 95.2%(95%CI,76.2%to 99.9%)and 100%(95%CI,86.3%to 100%),respectively.The agreement between the two researchers for T1 VISTA for diagnosis of CAD was very good(k=0.91).For patients without acute artery occlusion,all of them had a definite conclusion with or without dissection by T1 VISTA(n=29).However,for 17 patients with acute artery occlusion,the possibility of dissection could not be excluded for 6 of them by T1 VISTA(p=0.001).Conclusions:3D T1 VISTA at 3.0 Tesla was useful in the diagnosis of acute CAD.However,for some patients with total occlusion of the artery without typical imaging features of dissection,the unequivocal distinction between intramural haematoma and intraluminal thrombus may be not adequate by T1 VISTA alone.Future studies should investigate whether a follow-up scan,a contrast-enhanced imaging or an optimal VISTA technique could be useful.

Nanofiber self-consistent additive manufacturing process for 3D microfluidics

3D microfluidic devices have emerged as powerful platforms for analytical chemistry,biomedical sensors,and microscale fluid manipulation.3D printing technology,owing to its structural fabrication flexibility,has drawn extensive attention in the field of 3D microfluidics fabrication.However,the collapse of suspended structures and residues of sacrificial materials greatly restrict the application of this technology,especially for extremely narrow channel fabrication.In this paper,a 3D printing strategy named nanofiber self-consistent additive manufacturing(NSCAM)is proposed for integrated 3D microfluidic chip fabrication with porous nanofibers as supporting structures,which avoids the sacrificial layer release process.In the NSCAM process,electrospinning and electrohydrodynamic jet(E-jet)writing are alternately employed.The porous polyimide nanofiber mats formed by electrospinning are ingeniously applied as both supporting structures for the suspended layer and percolating media for liquid flow,while the polydimethylsiloxane E-jet writing ink printed on the nanofiber mats(named construction fluid in this paper)controllably permeates through the porous mats.After curing,the resultant construction fluid–nanofiber composites are formed as 3D channel walls.As a proof of concept,a microfluidic pressure-gain valve,which contains typical features of narrow channels and movable membranes,was fabricated,and the printed valve was totally closed under a control pressure of 45 kPa with a fast dynamic response of 52.6 ms,indicating the feasibility of NSCAM.Therefore,we believe NSCAM is a promising technique for manufacturing microdevices that include movable membrane cavities,pillar cavities,and porous scaffolds,showing broad applications in 3D microfluidics,soft robot drivers or sensors,and organ-on-a-chip systems.