幕上脑实质内神经鞘瘤的临床病理分析

目的:探讨幕上脑实质内神经鞘瘤的临床病理学特征。方法:回顾性分析2011年11月至2019年5月首都医科大学宣武医院诊断为幕上脑实质内神经鞘瘤的7例患者资料,分析其影像学特征、病理学和免疫组织化学特点,并复习相关文献。结果:幕上脑实质内神经鞘瘤7例患者中,男性4例,女性3例,年龄8~74岁,平均年龄30.6(8.0~74.0)岁。影像学及术中所见提示病变主要位于脑实质内,以大脑半球的单发病灶为主,2例位于脑室内并累及脑实质;CT、MRI均显示囊实性占位,MRI增强显示不均匀强化信号。组织病理学显示7例均表现为典型的神经鞘瘤,具有Antoni A区和Antoni B区,4例伴出血、囊性变及钙化,此外2例病例可见灶状坏死。7例(100%)均表达S-100、SOX-10和Vimentin,分别有1例表达GFAP及EMA;Ki-67增殖指数为3%~10%。7例患者术后均未接受化疗或放疗;除2例失访外,均未发现肿瘤复发。结论:脑实质内神经鞘瘤患者预后较好,但术前准确诊断是难点,病理学分析在脑实质内神经鞘瘤的诊断方面具有重要意义,关于脑实质内神经鞘瘤的发生发展机制尚需进一步研究。

Overexpression of ACE2 ameliorates Aβ-induced blood–brain barrier damage and angiogenesis by inhibiting NF-κB/VEGF/VEGFR2 pathway

Background:Pathological angiogenesis and blood–brain barrier damage may play an important role in Alzheimer's disease(AD).ACE2 is mainly expressed on the surface of endothelial cells in brain.Recent studies have shown that the expression of ACE2 in AD is reduced,but its role in AD is still unclear.Method:We induced AD damage in endothelial cells using Aβ25-35 and overexpressed ACE2 in bEend.3 cells through lentiviral transfection.We detected the effect of Aβ25-35 on cell viability using the CCK-8 assay and examined the effect of overexpressing ACE2 on angiogenesis using an angiogenesis assay.We used western blot and cell immunofluorescence to detect changes in the expression of the VEGF/VEGFR2 pathway,tight junction protein,and NF-κB pathway.Results:Aβ25-35 treatment significantly decreased the expression of ACE2 and reduced cell viability.ACE2 overexpression(1)reduced the number of branches and junctions in tube formation,(2)inhibited the activation of the VEGF/VEGFR2 pathway induced by Aβ25-35,(3)increased the expression of TJPs,including ZO-1 and claudin-5,and(4)restored Aβ25-35-induced activation of the NF-κB pathway.Conclusion:Overexpression of ACE2 can improve pathological angiogenesis and blood–brain barrier damage in AD models in vitro by inhibiting NF-κB/VEGF/VEGFR2 pathway activity.ACE2 may therefore represent a therapeutic target for endothelial cell dysfunction in AD.

Extracting Lotus Fields Using the Spectral Characteristics of GF-1 Satellite Data

The lotus(Nelumbo nucifera Gaertn.)is an aquatic plant that grows in shallow water and has long been cultivated in South China.It can improve the incomes of farmers and plays an important role in alleviating poverty in rural China.However,a modern method is required to accurately estimate the area of lotus fields.Lotus has spectral characteristics similar to those of rice,grassland,and shrubs.The features surrounding areas where it is grown are complex,small,and fragmented.Few studies have examined the remote sensing extraction of lotus fields,and automatic extraction and mapping are still challenging methods.Here,we compared the spectral characteristics of lotus fields and other ground objects and devised a remote sensing method for the rapid extraction of lotus fields.Using this method,the extraction accuracy of lotus was 96.3%.The Kappa coefficient was 0.926,which is higher than those of the unsupervised K-means classification,Mahalanobis distance,and support vector machine supervised classification,and demonstrates the potential of this method for extracting and mapping lotus fields by remote sensing.

Carbon Emission Effect of Land Use in Nanchang City and Its Optimization Countermeasures

Land use/coverage change(LUCC)exerts a profound influence on global carbon emission through changing structure and functions of ecosystem.Taking Nanchang City as an example,this study determined organic carbon emission of land ecosystem by ecosystem type method.In 2005,total carbon emission of Nanchang City was 4.826 2 Tg.In 2010,it became 5.535 9 Tg,showing a growth trend of carbon emission from land use change.The carbon emission of cropland and grassland decreased in 2005-2010,that of garden land and construction land had increase,and carbon absorption function of water land and other unused land was weakened.Due to difference of land use structure,the carbon emission of Nanchang City is varied.In 2005-2010,the rank of carbon emission from high to low is as follows:Nanchang County,Xinjian County,Jinxian County and Qingshanhu District.In combination with land use change and development plan of Nanchang City,Nanchang City should take carbon emission reduction measures,including conceding the land to forestry,returning the land to water,limiting excessive expansion of construction land,optimizing distribution of urban land use,flexibly regulating land supply policies,and establishing carbon trading legal system,to reach the objective of combining land use plan with ecological construction.

Mesoporous molecular sieve confined phase change materials with high absorption,enhanced thermal conductivity,and cooling energy charging/discharging capacity

The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition process.This is crucial for expanding their applications in the more demanding cold storage field.In this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the PCM.Owing to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling cycles.In comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal conductivity.Specifically,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane alone.All these highlight its significant potential for applications in the area of cold energy storage.

超大跨度异型钢连桥动态成型施工关键技术研究与应用

为重塑西安成为“一带一路”文化核心区,扩大文化交流在西安市内的开展面和贯入度,西安市政府建立“三中心”重点配套公共服务类建设项目———“一带一路”文化交流中心系列公建项目。“一带一路”文化交流中心系列公建项目北地块为400 m超长非对称双塔连体结构,其中150 m空中连桥是国内最大跨度的钢连桥单体。钢连桥重约42000 kN,与两端塔楼焊接连接,桥身主体由片式桁架、弧形三角桁架及其之间的水平梁撑组成。在连桥一端下部加设有36 m长、4500 kN重的下加腋结构。连桥投影下方为单、双层地下室的多标高顶板,施工条件复杂。现阶段提升施工的研究,多停留在跨度小、重量轻的连体结构整体提升的理论及实践分析上,而对于包含有上述非常规自身结构特点及各类外部复杂环境的超长超重连桥施工,未有成套的关键技术研究和应用成果。经过对钢连桥施工重、难点的全面分析,结合行业内提升施工的现有案例,创新研发了一套超大跨度异型钢连桥动态成型施工关键技术,包含超大跨度异型钢连桥动态成型线形控制技术、超大跨度异型钢连桥结构内力控制与应力监测技术、复杂工况下大体量钢连桥拼装施工危险源管控技术。异型钢连桥在动态成型过程中,加腋结构分步安装使得结构重心持续变动,对于结构成型线形控制提出了更大挑战。150 m大跨度连桥由多节段厚板钢材构件拼装成整体,经分阶段提升动态成型。成型过程中,内力不断重分布,因此施工过程的内力控制与实时监测至关重要。此外,连桥体量大,多数构件单重达300 kN,其拼装施工对于大型起重设备的需求与其投影下方地下室顶板相对较弱的承载能力之间的矛盾,对施工安全危险源管控技术提出了更高要求。该技术提出了非对称预拱技术、优化了焊接顺序优化、应用循环预拼装及虚拟预拼装,解决了非对称超长连桥线形控制控制难题;应用全周期仿真模拟,研发了“多吊点分布、主被动力结合”的提升体系,开发了“差值法”应力判别标准,解决了施工过程中结构内力与应力监测难题;提出了“钢支撑+后浇承台”楼板加固,研发了多标高拼装平台体系,确保施工安全性。

Co-Frequency Interference Analysis Between Ultra-Large-Scale NGSO Constellations and GSO Systems

The rejuvenation of non-geostationary orbit(NGSO)satellite communication holds the promise of seamless and ubiquitous broadband access from the space.However,the NGSO constellations must share the scarce radio spectrum resources with geostationary orbit(GSO)satellite systems,which results in dynamically changing and unevenly distributed interference to GSO systems.In this context,the ultra-large-scale NGSO constellation incurs a more complicated interference environment with GSO systems,which raises urgent demands on inter-system interference evaluation.In this case,we investigate the inter-system downlink interference from a NGSO satellite mega-constellation to a GSO earth station.Specifically,we consider the scenario where the NGSO and GSO earth stations are co-located,and apply a novel visibility analysis method in the interference modeling to reduce computation redundancy.The interference evaluation is then performed through comprehensive simulations,in which the Starlink constellation with more than 4000 satellites is examined for the first time.The simulation results demonstrate various states of interference on the GSO earth station at different deployment locations.It reveals that the number of visible satellites could influence the angle between the main lobe directions of NGSO satellites and the GSO earth station antenna,which further affects the interference level.