Open AccessAmplifying colorectal cancer progression:impact of a PDIA4/SP1 positive feedback loop by circPDIA4 sponging miR-9-5p

Objective:Colorectal cancer(CRC)is a prevalent malignant tumor with a high fatality rate.CircPDIA4 has been shown to have a vital role in cancer development by acting as a facilitator.Nevertheless,the impact of the circPDIA4/miR-9-5p/SP1 axis on development of CRC has not been studied.Methods:Western blot,immunohistochemistry,and reverse transcription-quantitative polymerase chain reaction assays were used to analyze gene expression.The CCK-8 assay was used to assess cell growth.The Transwell assay was used to detect invasion and migration of cells.The luciferase reporter and RNA immunoprecipitation tests were used to determine if miR-9-5p and circPDIA4(or SP1)bind to one another.An in vivo assay was used to measure tumor growth.Results:It was shown that circPDIA4 expression was greater in CRC cell lines and tissues than healthy cell lines and tissues.CircPDIA4 knockdown prevented the invasion,migration,and proliferation of cells in CRC.Additionally,the combination of circPDIA4 and miR-9-5p was confirmed,as well as miR-9-5p binding to SP1.Rescue experiments also showed that the circPDIA4/miR-9-5p/SP1 axis accelerated the development of CRC.In addition,SP1 combined with the promoter region of circPDIA4 and induced circPDIA4 transcription.CircPDIA4 was shown to facilitate tumor growth in an in vivo assay.Conclusions:The circPDIA4/miR-9-5p/SP1 feedback loop was shown to aggravate CRC progression.This finding suggests that the ceRNA axis may be a promising biomarker for CRC patient treatment.

An Underwater Robot Inspection Anomaly Localization Feedback System Based on Sonar Technology

This article introduces an underwater robot inspection anomaly localization feedback system comprising a real-time water surface tracking,detection,and positioning system located on the water surface,while the underwater robot inspection anomaly feedback system is housed within the underwater robot.The system facilitates the issuance of corresponding mechanical responses based on the water surface’s real-time tracking,detection,and positioning,enabling recognition and feedback of anomaly information.Through sonar technology,the underwater robot inspection anomaly feedback system monitors the underwater robot in real-time,triggering responsive actions upon encountering anomalies.The real-time tracking,detection,and positioning system from the water surface identifies abnormal conditions of underwater robots based on changes in sonar images,subsequently notifying personnel for necessary intervention.

Controlling Chaos in a Semiconductor Laser via Weak Optical Positive Feedback and Modulating Amplitude

Numerical analysis of weak optical positive feedback （OPF） controlling chaos is studied in a semiconductor laser. The physical model of controlling chaos produced via modulating the current of semiconductor laser is presented under the condition of OPF. We find the physical mechanism that the nonlinear gain coefficient and linewidth enhance- ment factor of the laser are affected by OPF so that the dynamical behaviour of the system can be efficiently controlled. Chaos is controlled into a single-periodic state, a dual-periodic state, a tri-periodic state, a quadr-periodic state, a pentaperiodic state, and the laser emitting powers are increased by OPF in simulations. Lastly, another chaos-control method with modulating the amplitude of the feedback light is presented and numerically simulated to control chaotic laser into multi-periodic states.

Two Positive Periodic Solutions of Delay Functional Difference System with Feedback Control

By using a fixed point theorem on a cone to investigate the existence of two positive periodic solutions for the following delay difference system with feedback control argument of the form {△x（n）=-b（n）x（n）＋f（n,x（n-τ1（n））,…,x（n-τm（n））,u（n-δ（n）））,△u（n）=-η（n）u（n）＋a（n）x（n-σ（n））,n∈Z.

Experimental study of delayed positive feedback control for a flexible beam

Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing the maximal real part of characteristic roots of the system. A DSP-based experiment system is introduced. Simulation and experimental results indicate that the delayed positive feedback control may effectively reduce the beam vibration if time delay is appropriately selected.

Analysis of positive feedback in the control of movement

Over the past three decades, neurophysiologists studying the neural circuitry responsible for control of skeletal muscles have developed several different general theories of sensorimotor control. These have usually invoked one or more of the sources of proprioceptive signals (e.g. muscle spindle and Golgi tendon organ afferents) in positive or negative feed-back loops to the homonymous alpha motoneurones. In this paper we consider to analyze the role of posi-tive feedback in combination of negative feedback due to important role of them in stabilizing the neu-romuscular system.

Explosive synchronization in a mobile network in the presence of a positive feedback mechanism

Synchronization is a process that describes the coherent dynamics of a large ensemble of interacting units.The study of explosive synchronization transition attracts considerable attention.Here,I report the explosive transition within the framework of a mobile network,while each oscillator is controlled by global-order parameters of the system.Using numerical simulation,I find that the explosive synchronization(ES)transition behavior can be controlled by simply adjusting the fraction of controlled oscillators.The influences of some parameters on explosive synchronization are studied.Moreover,due to the presence of the positive feedback mechanism,I prevent the occurrence of the synchronization of continuous-phase transition and make phase transition of the system a first-order phase transition accompanied by a hysteresis loop.

Hopf Bifurcation of a Positive Feedback Delay Differential Equation

Under some minor technical hypotheses, for each T larger than a certain rS > 0, Krisztin, Walther and Wu showed the existence of a periodic orbit for the positive feedback delay differential equation x(t) = -rμx(t) + rf(x(t-1)), where r and μ are positive constants and f : R → R satisfies f(0) = 0 and f' > 0. Combining this with a unique result of Krisztin and Walther, we know that this periodic orbit is the one branched out from 0 through Hopf bifurcation. Using the normal form theory for delay differential equations, we show the same result under the condition that f ∈ C3(R,R) is such that f''(0) = 0 and f'''(0) < 0, which is weaker than those of Krisztin and Walther.

基于相似度加速的自适应聚类联邦学习

为了解决联邦学习过程中数据异质性导致模型性能下降的问题,考虑对联邦模型个性化,提出了一种新的基于相似度加速的自适应聚类联邦学习(ACFL)算法,基于客户端本地更新的几何特性和客户端联邦时的正向反馈实现自适应加速聚类,将客户端划分到不同任务簇,同簇中数据分布相似的客户端协同实现聚类联邦学习(CFL),从而提升模型性能。该算法不需要先验确定类簇数量和迭代划分客户端,在避免现有基于聚类的联邦算法计算成本过高、收敛速度慢等问题的同时保证了模型性能。在常用数据集上使用深度卷积神经网络验证了ACFL的有效性。结果表明,所提算法性能与聚类联邦学习算法相当,优于传统的迭代联邦聚类算法(IFCA),且具有更快的收敛速度。

一维光学位置传感器融合的非接触多自由度位姿测量系统

为实现机器人末端位姿多自由度实时测量反馈,融合一维光学位置传感器(Position Sensitive Detector,PSD)建立了平面3自由度非接触测量系统,对其测量原理,信号处理电路,环境光干扰去除和非线性标定算法等进行研究。根据PSD传感器测量特性和平面3自由度测量要求设计了4-PSD测量系统,并建立测量系统数学模型。研究了PSD传感器的信号处理电路,通过运放和除法器实现了单个PSD的信号处理,结合单片机与A/DC采样电路,实现了上位机的高频率信号采集。对4-PSD测量系统进行预实验,为消除环境光干扰,通过激光调制和数字滤波等方法进行验证。最后,通过激光位移传感器标定4-PSD测量系统,介绍了4-PSD的标定步骤(原点、转角、长度和二阶非线性标定),测定了系统标定后的误差分布。该测量系统具有较高的测量频率(50 Hz)。标定实验结果表明:标定后的4-PSD测量系统在70 mm×70 mm内,测量精度平均为0.49 mm,比标定前降低了90%的误差,能满足大部分高速、高精度机器人末端的非接触式实时测量反馈需求。

白果内酯调控AMPK-SIRT3正反馈环路介导的线粒体生物发生改善ATDC5软骨细胞炎性损伤

旨在以AMPK-SIRT3正反馈环路为切入点,探讨白果内酯改善白介素1β(IL-1β)诱导的ATDC5软骨细胞炎性损伤的作用机制。采用IL-1β(10 ng·mL^(-1))诱导ATDC5软骨细胞炎性损伤来构建体外骨关节炎模型,随机分为对照组,IL-1β组,IL-1β和白果内酯共同处理组,其中,共同处理组按照白果内酯的应用浓度又分为低、中和高(15、30和60μmol·L^(-1))3个不同剂量组。免疫印迹法(Western blot)和实时荧光定量PCR(qRT-PCR)方法检测各组软骨细胞中ADAMTS4、PGC-1a、Collagen Type II、MMP-3、NRF-1和Fis1的蛋白与mRNA表达情况。试剂盒检测各组ATP含量,并通过免疫荧光方法检测SIRT3表达水平。Western blot检测AMPK-SIRT3正反馈环路相关蛋白p-AMPK、AMPK和SIRT3表达水平。使用Compound C和3-TYP处理ATDC5软骨细胞,构建AMPK-SIRT3信号通路阻断模型,检测下游PGC-1a、NRF-1和Fis1蛋白变化。结果显示,白果内酯通过下调ADAMTS4和MMP-3表达(P<0.05),促进Type II collagen表达(P<0.05)来调节ECM代谢平衡,并促进ATP合成。在机制上,白果内酯干预软骨细胞后p-AMPK、SITR3、PGC-1a和NRF-1水平显著升高(P<0.05),而Fis1蛋白水平显著降低(P<0.05),并且使用Compound C和3-TYP预处理软骨细胞后,PGC-1a、NRF-1和Fis1蛋白水平被不同程度抑制。综上所述,白果内酯通过AMPK-SIRT3正反馈环路激活PGC-1a,调节线粒体生物发生改善ATDC5软骨细胞炎性损伤。

股票市场正反馈交易的空间溢出效应——基于新冠疫情冲击的计量检验

利用空间自相关正反馈交易模型,对新冠疫情爆发前后国际股票市场的正反馈交易进行了检验.结果表明,新冠疫情爆发后国际股票市场正反馈交易显著增强并呈现空间相关特征.相关国家反危机的调控措施,虽然一度抑制了股票市场下行,但同时强化了投资者非理性的外推性预期,加剧了股票市场正反馈交易的空间溢出效应.因此,在新冠疫情不断持续的情况下,监管当局应充分考虑反危机调控措施对投资者心理账户和市场预期的影响,防范疫情冲击下股票市场正反馈交易空间溢出的风险联动效应.

有求必应,还是相“机”而动?员工反馈寻求行为对上级发展性反馈的影响机制研究

员工反馈寻求行为逐渐成为学者们研究的热点话题。已有研究主要从反馈寻求主体的视角探究其对员工自身的影响,但对该行为如何影响领导反馈结果关注不够。基于归因理论和情绪评价理论,本文探讨了员工反馈寻求行为影响上级发展性反馈的过程机制和边界条件。基于310份2时点领导-员工配对数据,本研究采用多水平路径分析和蒙特卡洛模拟的方法对研究假设进行了检验,结果显示:第一,当领导绩效改进动机归因高时,员工反馈寻求行为与积极情绪的正向关系更强;当领导绩效改进动机归因低时,员工反馈寻求行为与消极情绪的正向关系更强。第二,积极情绪对上级发展性反馈具有正向影响;消极情绪对上级发展性反馈具有负向影响。第三,积极情绪和消极情绪在员工反馈寻求行为和绩效改进动机归因的交互上对上级发展性反馈的影响起中介作用,从而表现出有中介的调节作用。研究结果深化了员工反馈寻求行为的作用机制研究,也为企业促进员工反馈寻求行为和上级发展性反馈提供了实践启示。

基于单因子抗差估计的SINS/DR高速列车组合导航定位研究

为了有效抑制列车长时间运行下SINS系统定位误差的快速积累,并解决GNSS/SINS组合导航系统在卫星信号故障时不能正常工作的问题,提出了一种基于单因子抗差估计的SINS/DR组合导航定位算法,在SINS系统基础上,引入车载里程仪,作为一种提供列车航位推算数据的设备,通过卡尔曼滤波器的反馈校正获得列车导航参数的最优估计值。在传统卡尔曼滤波器的基础上引入一种自适应调节因子,强化了卡尔曼滤波器的反馈校正效果,保证了在系统建模不准确时仍可获得列车导航参数的最优估计值。计算机仿真结果表明,设计的组合导航定位算法不仅可以保证高速列车长时间运行的定位精度和稳定性,而且在高速列车紧急制动的情况下仍具备较强的抗干扰能力,可以满足列车定位的基本要求。

一种新型3-RRPU并联机构的运动学及鲁棒控制研究

针对现有的三平移并联机构大多正解不唯一、较难实现精确稳定运动控制的问题,提出了一种新的3-RRPU型三平移并联机构,同时研究了机构的运动学、动力学及轨迹跟踪控制方法。首先,运用螺旋理论分析了该机构三平移的原理,进行了驱动输入的选取与论证,对机构平台奇异性、驱动奇异性和支链奇异性进行了分析;其次,运用运动学理论建立了运动学模型,推导了位置正、逆解析解;再次,运用拉格朗日动力学理论建立了机构操作空间的刚体动力学模型;最后,提出了一种基于非线性反馈解耦的自适应滑模轨迹跟踪控制方法,以证明其控制稳定性,并基于动力学模型对空间轨迹跟踪精度和控制力矩进行了仿真分析。研究结果表明:3-RRPU并联机构的位置正解在一般位形下具有唯一性,机构的平台奇异位形和驱动奇异位形少且无支链奇异。该轨迹控制方法可使机构在载荷20 kg、速度0.18 m/s、加速度0.12 m/s 2下,实现0.002 m以内的高精度复杂轨迹跟踪;基于Sigmoid函数的轨迹控制方法还能有效削弱控制力矩的抖振,为实现工业领域高速、高精度、高性能的三平移运动提供了新方法。

热失控状态气液两相的锂离子电池建模及修正方法研究

锂离子电池在应用过程中因滥用而发生热失控现象,导致电池内部产生大量气体,传统的固液两相模型难以准确描述热失控机理。针对以上问题,以18650电池组为研究对象,构建气液两相的锂离子电池模组的电化学-热耦合模型,研究了热失控气体对锂离子电池内部应力、温度、电解液浓度的影响规律,同时利用COMSOL Multiphysics 5.5软件进行了有效性验证和理论模型修正。研究结果表明,锂离子电池热失控气体对电池内部应力、温度、电解液浓度有着明显的正反馈影响规律。内部应力的理论修正值与仿真值峰值均在相近时刻出现,且误差为0.04 MPa,计算精确率提高了80%。电池内部温度到60℃左右时发生热失控,产生的热失控气体在内部温度升高到160℃时被点燃,640 s时达到最高仿真温度,修正温度分别为177、172℃,热失控气体产生的热点现象是影响电池包内部的温度分布不均的主要原因。电解液浓度理论修正值和仿真值从1 200 mol/m3同步下降至837 mol/m3,形成气液两相流,电解液与电极材料反应和分解造成了电解液浓度降低。

数据要素乘数效应的内涵与实现逻辑

数据是数字经济时代的关键生产要素,国家高度重视发挥数据要素乘数效应、赋能经济社会发展。基于凯恩斯主义经济学框架分析数据要素乘数效应的内涵,结合数据要素乘数效应的有利条件和制约因素分析其实现逻辑。研究发现,数据要素乘数效应的内涵包括溢出效应和反馈效应两方面,数据要素的开发利用可以提升投资水平、消费水平、供需匹配效率和政府调控能力等,从而实现溢出效应。研究还发现,数据要素开发利用过程中,可以通过干中学不断提高原始数据积累水平、畅通数据流通渠道、提高数据分析能力,从而实现反馈效应。数据要素乘数效应的实现逻辑包括:非竞争性可以使数据要素实现报酬递增和正反馈循环,是数据要素可以发挥乘数效应的根本原因;规模经济、正外部性、干中学效应和生产力跃迁是数据要素发挥乘数效应的有利条件;低数据质量、隐私负外部性、数据共享机会成本、数据安全保护成本等可能制约数据要素发挥乘数效应。研究表明,要促进企业数字化转型,构建跨界融合的数据要素应用生态;加强数商生态体系培育,畅通数据要素流通渠道;完善数据要素安全保护制度和公共服务,培育数据安全风险管理产业生态;以效率和公平为目标,完善数据要素收益分配机制。

基于自适应分数阶正位置反馈的垂尾振动主动控制

针对自适应正位置反馈(Adaptive Positive Position Feedback,APPF)控制器在控制效果与分数阶正位置反馈(Fractional Order Positive Position Feedback,FOPPF)控制器在针对摄动区间小的不足,提出一种分数阶APPF(Fractional Order Adaptive Positive Position Feedback,FOAPPF)控制器,使得控制器在控制效果提升的同时兼具强鲁棒性。基于不同参数对FOPPF控制器的影响,推导参数的最佳范围,将系统多个摄动模型的正弦扫频响应进行综合加权处理,并考虑系统远离共振频段的控制性能,构建附带约束条件的控制设计的目标函数。以粘有宏纤维复合材料(Macro Fiber Composites,MFC)的垂尾模型及其摄动模型为被控对象,设计相应的FOAPPF控制器。研究结果表明:相比FOPPF控制器,FOAPPF控制器闭环极点对参数摄动不敏感;相比APPF控制器,FOAPPF控制器的相频曲线在摄动频带内变化平缓,其控制效果受固有频率在线估计误差的影响更小;多种试验工况表明,FOAPPF控制器在不同摄动模型下均具有较好的控制效果,垂尾抖振响应均方根值至少降低了55%,且具有较好的鲁棒性,因此该控制器对垂尾结构的振动主动控制具有良好应用潜力。

基于反馈变换与积分反演PMSLM强鲁棒位置控制

为提高永磁同步直线电机位置控制系统的鲁棒性能,设计基于反馈线性化变换解耦系统的积分反演控制器。首先定义新的中间状态变量,通过状态反馈将永磁同步直线电机系统线性化解耦变换为带有非线性扰动状态的串联积分系统,避免常规反馈解耦时未知系数扰动状态无法补偿的问题;其次依据Lyapunov稳定条件设计反演控制器,在各级子系统的中间虚拟控制量的设计中加入积分环节,提高系统控制精度,并利用稳定条件设计扰动自适应律,估计并补偿系统扰动,提高永磁同步直线电机控制系统的鲁棒性能。最后搭建基于半实物仿真控制系统的试验平台,通过试验验证所提方法的正确性和有效性。