Data-driven modeling on anisotropic mechanical behavior of brain tissue with internal pressure

Brain tissue is one of the softest parts of the human body,composed of white matter and grey matter.The mechanical behavior of the brain tissue plays an essential role in regulating brain morphology and brain function.Besides,traumatic brain injury(TBI)and various brain diseases are also greatly influenced by the brain's mechanical properties.Whether white matter or grey matter,brain tissue contains multiscale structures composed of neurons,glial cells,fibers,blood vessels,etc.,each with different mechanical properties.As such,brain tissue exhibits complex mechanical behavior,usually with strong nonlinearity,heterogeneity,and directional dependence.Building a constitutive law for multiscale brain tissue using traditional function-based approaches can be very challenging.Instead,this paper proposes a data-driven approach to establish the desired mechanical model of brain tissue.We focus on blood vessels with internal pressure embedded in a white or grey matter matrix material to demonstrate our approach.The matrix is described by an isotropic or anisotropic nonlinear elastic model.A representative unit cell(RUC)with blood vessels is built,which is used to generate the stress-strain data under different internal blood pressure and various proportional displacement loading paths.The generated stress-strain data is then used to train a mechanical law using artificial neural networks to predict the macroscopic mechanical response of brain tissue under different internal pressures.Finally,the trained material model is implemented into finite element software to predict the mechanical behavior of a whole brain under intracranial pressure and distributed body forces.Compared with a direct numerical simulation that employs a reference material model,our proposed approach greatly reduces the computational cost and improves modeling efficiency.The predictions made by our trained model demonstrate sufficient accuracy.Specifically,we find that the level of internal blood pressure can greatly influence stress distribution and determine the possible related damage behaviors.

一种航天器实时外测数据处理软件设计与算法

航天器外测数据是飞行状态监视的一类重要跟踪数据,针对多任务大数据量下的外测数据实时处理软件的设计实现及关键处理算法问题,在分析外测数据实时处理软件特点及处理内容的基础上,给出了一种并行化处理的软件架构设计、结果帧结构、实现思路及运行模式,并对实时处理过程中的解模糊处理算法、插值算法、拼帧方法、电波折射修正方法、多点数据平滑算法等关键性技术进行了介绍,从而系统性地给出了一种适合外测数据实时性处理的工程化解决方案。研究结果对数据处理方法及处理软件设计等方面均有一定的借鉴意义。

Taxi origin and destination demand prediction based on deep learning:a review

Taxi demand prediction is a crucial component of intelligent transportation system research.Compared to region-based demand prediction,origin-destination(OD)demand prediction has a wide range of potential applications,including real-time matching,idle vehicle allocation,ridesharing services,and dynamic pricing,among others.However,because OD demand involves complex spatiotemporal dependence,research in this area has been limited thus far.In this paper,we first review existing research from four perspectives:topology construction,temporal and spatial feature processing,and other relevant factors.We then elaborate on the advantages and limitations of OD prediction methods based on deep learning architecture theory.Next,we discuss ongoing challenges in OD prediction,such as dynamics,spatiotemporal dependence,semantic differentiation,time window selection,and data sparsity problems,and summarize and compare potential solutions to each challenge.These findings offer valuable insights for model selection in OD demand prediction.Finally,we provide public datasets and open-source code,along with suggestions for future research directions.

Overview of machine learning-based traffic flow prediction

Traffic flow prediction is an important component of intelligent transportation systems.Recently,unprecedented data availability and rapid development of machine learning techniques have led to tremendous progress in this field.This article first introduces the research on traffic flow prediction and the challenges it currently faces.It then proposes a classification method for literature,discussing and analyzing existing research on using machine learning methods to address traffic flow prediction from the perspectives of the prediction preparation process and the construction of prediction models.The article also summarizes innovative modules in these models.Finally,we provide improvement strategies for current baseline models and discuss the challenges and research directions in the field of traffic flow prediction in the future.

血清ADA、IL-27、TB-Ab联合检测诊断血性结核性胸腔积液的价值研究

目的探讨血清腺苷脱氨酶(ADA)、白细胞介素-27(IL-27)及结核杆菌抗体免疫球蛋白G(TB-Ab-IgG)在血性结核性胸膜炎中的诊断价值。方法选取2015年7月-2017年3月在黄冈市中心医院诊治的102例胸腔积液患者作为研究对象。根据胸腔积液病因及性状分为血性癌性胸腔积液患者36例(癌性组)、血性结核性胸腔积液患者32例(结核性组)和非血性结核性胸腔积液患者34例(非结核性组)。检测并比较3组患者血清ADA、IL-27及TB-Ab-IgG水平。绘制受试者工作特征(ROC)曲线,评价ADA、IL-27及TB-Ab-IgG诊断血性结核性胸腔积液的敏感性和特异性。结果结核性组血清ADA、IL-27水平及TB-Ab-IgG阳性率高于癌性组和非结核性组(P<0.05)。ROC曲线结果显示,ADA、IL-27、TB-Ab-IgG及3者联合检测诊断血性结核性胸膜胸腔积液的曲线下面积分别为0.884、0.842、0.867和0.926,敏感性分别为91.4%(95%CI:0.555,0.832)、79.8%(95%CI:0.451,0.612)、85.7%(95%CI:0.712,0.931)和96.8%(95%CI:0.787,0.988),特异性分别为93.7%(95%CI:0.631,0.947)、83.6%(95%CI:0.833,0.964)、88.6%(95%CI:0.787,0.998)和94.3%(95%CI:0.834,0.999)。ADA、IL-27、TB-Ab-IgG 3者联合检测优于单独检测。结论ADA、IL-27、TB-Ab-IgG 3者联合检测诊断血性结核性胸膜炎具有较高的临床价值。

航天器返回可达区域国土占比快速计算方法

文章针对航天器再入返回地面过程中可达区进入国土区域部分的面积与整个可达区面积比值的实时快速计算问题,在传统平面图形算法的基础上,给出了考虑球面形状和再入可达区凹凸特性的三种计算方法:球面网格分割算法、球面纬线扫描统计算法、球面三角划分算法,对这三种算法的原理及实现过程进行了阐述,比较了三种算法的优缺点。实验结果表明,文章采用的三种算法均是可行的,三种算法原理区别明显,都有一定的优缺点,球面网格分割算法、球面纬线扫描统计算法精度低于球面三角划分算法,但较球面三角划分算法更易理解和实现,球面纬线扫描算法可达到与网格分割算法相同的精度,而耗时与之相较大大降低。研究结果对再入可达区或落点散布区的相关计算有一定参考意义。

航天器在轨运行可视化中姿态数据的处理方法

针对航天器在轨运行三维可视化显示中姿态数据使用时的野值剔除、插值及平滑等问题,对欧拉角和四元数2类常见姿态表达形式下的姿态数据处理方法进行了探讨。基于工程实际情况分别给出了未采用卡尔曼滤波的解决方法,并采用某实测数据进行了效果检验,实验结果及可视化原型软件的应用表明该方法可行。研究结果对航天器姿态计算、可视化使用时的数据处理等均有一定参考意义。

一种航天器返回覆盖区面积快速计算方法

针对航天器再入返回过程中地面覆盖区进入国境内部分面积及面积占比的快速估计问题,给出了一种考虑球面形状的纬线分割扫描算法。通过将传统的经纬度二维方向划分算法降维处理,仅在纬线方向上进行分割,并扩展到球面上,实现了覆盖区相交部分面积及面积占比的快速估计,并对算法进行了仿真计算验证。结果表明:对给定的算例,计算耗时控制在0.4 s以内,面积占比的误差在0.2%以内,方法可行,且满足实时性要求。

制导率未知时返回弹道自适应抗差滤波计算

针对制导率未知状态下返回弹道的自适应抗差估计问题,基于工程实际情况建立了一种无迹卡尔曼滤波(Unscented Kalman Filter,UKF)算法,给出了状态模型及观测模型,并运用基于机动检测及模型切换的自适应处理方法、基于加速度模型补偿的自适应处理方法来实现对返回段机动过程的实时跟踪。仿真计算结果表明,所给出的计算方法是可行的,所提出的基于加速度模型补偿的自适应处理算法较好地实现了对返回弹道的抗差估计处理。研究结果对返回弹道实时估计有一定的参考价值。

航天器陨落落点计算偏差分析

航天器陨落落点计算的精度受多种影响因素制约,基于工程实际情况,从各类摄动力的对比、大气阻力参数的影响及初始位置速度误差影响等方面对主要影响因素产生的原因和影响量级进行了分析。同时,为分析落点在飞行弹道、飞行方向的偏离情况,对飞行弹道径切法各方向上加速度值进行了对比。结果表明,地球阻力和大气作用都会在法向产生分量,使落点偏离原弹道方向。研究结果对航天器陨落及返回落点的计算及分析有一定的参考价值。

大角度机动下火箭欧拉角姿态计算相关问题探讨

针对大角度机动条件下的火箭欧拉角姿态解算、连续性要求下的姿态角计算、星箭分离姿态计算等火箭飞行姿态相关问题,基于工程实际情况给出相应的解决办法,分析计算中存在的问题及应对措施,给出计算结果、对比情况及经验总结。研究结果对火箭姿态计算、卫星姿态分析等均有一定的参考价值。

基于星光角距/激光测距的卫星组合导航方法

为了进一步提高卫星天文自主导航精度,提出了一种利用激光测距辅助的天文组合导航方法。激光测距能够直接获取卫星到地面参考信标的高精度距离信息,在以星光角距为观测量的天文导航系统中引入激光测距辅助数据,可以拓展滤波器观测量的维度,从而改善滤波效果。由于组合导航系统为非线性系统,为避免泰勒展开线性化引起的二阶截断误差,采用UKF滤波方法进行组合导航系统信息融合。仿真结果表明,所提出的组合导航方法能够明显提升导航精度,改善滤波性能。

Expression of NF-κ B and osteopontin of synovial fluid of patients with knee osteoarthritis

Objective:To explore the significance of osteopontin and nuclear factorκB(NF-κB) expression in patients with knee osteoarthritis.Methods:RT-PCR and enzyme-linked immunosorbent assay were used to measure the Osteopontin(OPN) and NF-κB concentration of knee joint synovial fluid of patients with knee osteoarthritis and trauma fractures,and analyze the relationship between the expressiones of them.Results:OPN and NF-κB expression at the mRNA and protein levels of patients with knee osteoarthritis were significantly higher than the control group, the result showed statistical significance(P【0.05).There was a positive correlation between the OPN levels in synovial fluid of patients with knee osteoarthritis and NF-κB expression levels (P【0.05).Conclusions:The high expression of OPN and NF-κB are closely related to occurrence and development of knee osteoarthritis.

再入覆盖区域面积计算的一种球面矢量方法

针对航天器升力式再入返回地球过程中地面再入区域面积及其进入目标区域部分面积计算的实际工程需求,将平面多边形面积计算中常用的有向面积概念扩充到球面之上,给出了一种考虑球面形状的面积计算方法,计算结果表明该方法是可行的,并归纳出了该方法的优缺点及使用建议。研究结果对航天器再入区域相关计算有一定的参考意义。

基于外测观测的再入飞行转弯方向辨识方法

针对航天器再入返回过程中无遥测数据、仅外测观测下的飞行转弯方向实时辨识问题,分析了航天器再入飞行时的主要受力情况,给出了一种采用非动力学建模及UKF滤波框架的航天器再入飞行速度估计算法。在此基础上提出了一种使用前后时刻速度或速度增量在轨道面的法线分量判断单点转弯方向的方法,并通过多点滑窗统计方法实时给出了转弯方向的辨识结果,减少了误判的几率。实验结果表明此转弯方向辨识算法是可行的,研究结果对再入飞行弹道计算及转弯方向估计有一定的参考意义。

Key Role of CD151-integrin Complex in Lung Cancer Metastasis and Mechanisms Involved

Tetraspanin CD151 was found to be upregulated in malignant cell types and has been identified as a tumor metastasis promoter.In this study,we aimed to examine the role of the CD151-integrin complex in lung cancer metastasis and the underlying mechanisms.CD151 QRD194–196→AAA194–196 mutant was generated and used to transfect A549 human lung adenocarcinoma cells.We found that there was no significant difference in CD151 protein expression between CD151 and CD151-AAA mutant groups.In vitro,CD151-AAA mutant delivery abrogated the migration and invasion of A549 cells,which was promoted by CD151 gene transfer.Furthermore,CD151-AAA delivery failed to activate FAK and p130Cas signaling pathways.Western blot and immunohistochemical staining showed strong CD151 expression in lung cancerous tissues but not in adjacent normal tissues.Increased level of CD151 protein was observed in 20 of the patients and the positive rate of CD151 protein in specimens was 62.5%(20/32).In addition,CD151 was co-localized withα3 integrin at the cell-cell contact site in carcinoma tissues.These results suggested that the disruption of the CD151-α3 integrin complex may impair the metastasis-promoting effects and signaling events induced by CD151 in lung cancer.Our findings identified a key role for CD151-α3 integrin complex as a promoter in the lung cancer.

IgG4-Related Disease:A Retrospective Chinese Study of Features and Treatment Response of 98 Patients Including 4 Rare Cases

The features and treatment of 98 Chinese patients with immunoglobulin G4 (IgG4)-related disease (IgG4-RD) referred to a single tertiary referring centre were reviewed. Patientsdiagnosed with IgG4-RD according to the comprehensive diagnostic criteria (CDC) were includedin the retrospective study from May 2012 to March 2019. We collcted data on clinical, laboratory,imaging, histological features and treatment. Totally, 98 patients with IgG4-RD were enrolled.The common clinical manifestations included abdominal pain, salivary gland swelling andlymphadenopathy. 51% of the patients had multiple organs involvement. Lymph nodes, pancreasand salivary glands were most commonly involved. Four rare sites including ulna, cerebellum,scalp, and mammary gland were found. The serum IgG4 level was increased by 85.7%. The serumIgG4 level was positively correlated with the number of involved organs, IgG and IgG4/IgG. LowC3 and C4 levels were observed in 37.5% and 12.2% patients respectively, and all patients withkidney involvement had hypocomplementemia. A total of 54 patients underwent tissue biopsies,and 55.6%, 31.5% and 11.1% cases were diagnosed as definite, probable and possible IgG4-RD,respectively. Eighty-eight patients received glucocorticoids (GCs) therapy. Five patients underwentradical surgery to remove the lesion. 73% of them presented a complete or partial remission. IgG4-RD is a systemic fibroinflammatory disease with involvement of multiple organs throughout thebody including some rare sites. Most IgG4-RD patients had increased serum IgG4 levels andpatients with kidney involvement showed bypocomplementermia. GCs therapy is effective. Moreresearch is needed to provide a more reliable basis for the diagnosis and treatment of patients.

Delay-dependent exponential stability criteria for stochastic systems with polytopic-type uncertainties

This paper considers the problem of delay-dependent exponential stability in mean square for stochastic systems with polytopic-type uncertainties and time-varying delay. Applying the descriptor model transformation and introducing free weighting matrices, a new type of Lyapunov-Krasovskii functional is constructed based on linear matrix inequalities （LMIs）, and some new delay-dependent criteria are obtained. These criteria include the delay-independent/rate- dependent and delay-dependent/rate-independent exponential stability criteria. These new criteria are less conservative than existing ones. Numerical examples demonstrate that these new criteria are effective and are an improvement over existing ones.

航天器地面实时飞行计算软件质量保证方法

航天器地面实时飞行计算软件是地面测控软件系统的重要组成部分。针对该类软件的质量控制目标,在分析实时飞行计算软件特点的基础上,结合实际出现的问题及经验教训,对提高该类软件的可靠性、降低软件风险的方法进行了探讨,并对该类软件工程化实施的各环节进行了分析,给出了一些与工程实际相适应的具体建议,为航天器地面实时飞行计算软件的质量控制提供了有益参考。

机床造型设计中的人机尺寸应用研究

为提升数控机床软实力,增加产品的隐性价值,从整体到局部分析归纳机床造型设计中涉及的人机数据,以此建立人机尺寸表与隐性价值链图。将人机数据应用在滚刀复合磨床的造型设计中,针对设计过程中发现的易被忽视的人机要点,提出了对应的优化方案,完善了该机床的人机设计。该研究成果可为机床人机工程设计提供参考,提升机床用户操作的舒适性。