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A Lower and Upper Bound Method for Complex System Reliability Evaluation

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Journal of Donghua university(English Edition) 2011年第5期28卷 445-450页

作者：魏展明周凡陈耀武 college of biomedical engineering & instrument science Zhejiang University

It is hard for the existing methods to obtain the expression of the system reliability for most of the practical complex systems with a large number of components and possible stales. A new regression algorithm based on the lower and upper bounds is presented in this paper, which can obtain the system reliability analytically without concerning the structure of the complex system. The method has been applied to a real system and the reliability results are compared with those acquired by the classical method and the parametric method. The effectiveness and accuracy of the proposed method have been testified.

关键词： reliability lower bound upper bound regression algorithm

Optimization of a Multi-node System Reliability Model

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Journal of Donghua university(English Edition) 2011年第5期28卷 451-455页

作者：魏展明周凡陈耀武 college of biomedical engineering & instrument science Zhejiang University

In order to improve the reliability of an electronic or a computer system, redundant components always need to be added as part of the system. When an active component falls, a standby component will be activated to guarantee the system in operation continuously. The standby component and the switching device have been usually assumed to be continuously functional duriv,g the setup of the reliability model. In fact, it is these two asstuxtptions that induce deviations during modeling and introduce variances for the system reliability design. Through modeling and optiming the dependability of the synchronous clock system that decomposed from a multi-node system, a new reliability model which takes these two elements into consideration has been developed. Simulation results demonstrate that the upgraded reliability model is closer Io the actual dependability of the real system. The capability of the system reliability design is also improved as a result.

关键词： reliability redundancy hot-spare cold standby switch

Time-dependent diffusion magnetic resonance imaging:measurement,modeling,and applications

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Journal of zhejiang university-science A(Applied Physics & engineering) 2024年第10期25卷 765-787页

作者： Ruicheng BA Liyi KANG Dan WU Key Laboratory for biomedical engineering of Ministry of Education Department of Biomedical EngineeringCollege of Biomedical Engineering&Instrument ScienceZhejiang UniversityHangzhou 310027China

Increasingly,attention is being directed towards time-dependent diffusion magnetic resonance imaging(TDDMRI),a method that reveals time-related changes in the diffusional behavior of water molecules in biological tissues,thereby enabling us to probe related microstructure *** ongoing improvements in hardware and advanced pulse sequences,significant progress has been made in applying TDDMRI to clinical *** development of accurate mathematical models and computational methods has bolstered theoretical support for TDDMRI and elevated our understanding of molecular *** this review,we introduce the concept and basic physics of TDDMRI,and then focus on the measurement strategies and modeling approaches in short-and long-diffusion-time ***,we discuss the challenges in this field,including the requirement for efficient scanning and data processing technologies,the development of more precise models depicting time-dependent molecular diffusion,and critical clinical applications.

关键词： Time-dependent diffusion Diffusion magnetic resonance imaging(dMRI) Microstructure imaging Microstructural model

Some nonlinear parameters of PP intervals of pulse main peaks

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Journal of zhejiang university-science A(Applied Physics & engineering) 2007年第8期8卷 1256-1262页

作者： HAN Qing-peng WANG Ping School of biomedical engineering and instrument science Zhejiang University Hangzhou 310027 China

The PP intervals of pulse main peaks from healthy and unhealthy people(arrhythmia) have different nonlinear char-acteristics. In this paper,the extraction of PP intervals of pulse main peaks is achieved by picking up P peaks of pulse wave with wavelet transform. Furthermore,several nonlinear parameters(correlative dimensions,maximum Lyapunov exponents,com-plexity and approximate entropy) of the PP intervals of pulse main peaks extracted from normal and unhealthy pulse signals are calculated,with the results showing that these nonlinear parameters calculated from the main wave interval signals are helpful for analyzing human's health state and diagnosing heart diseases.

关键词： PP intervals of pulse main peaks Phase space reconstruction Correlative dimension Lyapunov exponent Complexity Approximate entropy

Towards high-density recording of brain-wide neural activity

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science China Materials 2018年第3期61卷 432-434页

作者： Bo Liang Xuesong Ye college of biomedical engineering and instrument science Key Laboratory of Biomedical Engineering of Ministry of Education Biosensor National Special Laboratory Zhejiang University

Brain activity is highly structured within local microcircuits and brain-wide networks,involving exquisite coordination across multiple brain regions in both superficial and deep structures^([1]).To understand how bra... 详细信息

关键词： Towards high-density recording of brain-wide neural activity

Changes of paired-pulse evoked responses during the development of epileptic activity in the hippocampus

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Journal of zhejiang university-science B(Biomedicine & Biotechnology) 2011年第9期12卷 704-711页

作者： Zhou-yan FENG Xiao-jing ZHENG Cong TIAN Yang WANG Hao-yu XING Ministry of Education Key Lab of biomedical engineering College of Biomedical Engineering & Instrument ScienceZhejiang UniversityHangzhou 310027China

Dysfunction of inhibitory synaptic transmission can destroy the balance between excitatory and inhibitory synaptic inputs in neurons,thereby inducing epileptic *** aim of the paper is to investigate the effects of successive excitatory inputs on the epileptic activity induced in the absence of ***-pulse orthodromic and antidromic stimulations were used to test the changes in the evoked responses in the ***(PTX),γ-aminobutyric acid(GABA) type A(GABA A) receptor antagonist,was added to block the inhibitory synaptic transmission and to establish the epileptic *** evoked population spike(PS) was recorded in the CA1 region of the *** results showed that the application of PTX induced a biphasic change in the paired-pulse ratio of PS amplitude.A short latency increase of the second PS(PS2) was later followed by a reappearance of PS2 *** type of depression was observed in both orthodromic and antidromic paired-pulse responses,whereas the GABAergic PS2 depression [called paired-pulse depression(PPD)] during baseline recordings only appeared in orthodromic-evoked *** addition,the depression duration at approximately 100 ms was consistent with a relative silent period observed within spontaneous burst discharges induced by prolonged application of *** conclusion,the neurons may ignore the excitatory inputs and intrinsically generate bursts during epileptic *** depolarization block could be the mechanisms underlying the PPD in the absence of GABA A *** distinct neuronal responses to stimulations during different epileptic stages may implicate the different antiepileptic effects of electrical stimulation.

关键词： Epilepsy Paired-pulse depression γ-Aminobutyric acid(GABA) Picrotoxin(PTX) CA1 region In-vivo

A bidirectional brain-computer interface for effective epilepsy control

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Journal of zhejiang university-science C(Computers and Electronics) 2014年第10期15卷 839-847页

作者： Yu QI Fei-qiang MA Ting-ting GE Yue-ming WANG Jun-ming ZHU Jian-min ZHANG Xiao-xiang ZHENG Zhao-hui WU Qiushi Academy for Advanced Studies Zhejiang University Department of Computer science Zhejiang University Second Affiliated Hospital of zhejiang university college of Medicine college of biomedical engineering and instrument science Zhejiang University

Brain-computer interfaces(BCIs) can provide direct bidirectional communication between the brain and a machine. Recently, the BCI technique has been used in seizure control. Usually, a closed-loop system based on BCI is set up which delivers a therapic electrical stimulus only in response to seizure onsets. In this way, the side effects of neurostimulation can be greatly reduced. In this paper, a new BCI-based responsive stimulation system is proposed. With an efficient morphology-based seizure detector, seizure events can be identified in the early stages which trigger electrical stimulations to be sent to the cortex of the brain. The proposed system was tested on rats with penicillin-induced epileptic seizures. Online experiments show that 83% of the seizures could be detected successfully with a short average time delay of 3.11 s. With the therapy of the BCI-based seizure control system, most seizures were suppressed within 10 s. Compared with the control group, the average seizure duration was reduced by 30.7%. Therefore, the proposed system can control epileptic seizures effectively and has potential in clinical applications.

关键词： Brain-computer interface Epilepsy Seizure detection Responsive neurostimulation

A mini-review and perspective on ferroptosis-inducing strategies in cancer therapy

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Chinese Chemical Letters 2019年第4期30卷 847-852页

作者： Shuaifei Wang Hongwei Liao Fangyuan Li Daishun Ling Institute of Pharmaceutics College of Pharmaceutical Sciences Zhejiang University Hangzhou Institute of Innovative Medicine College of Pharmaceutical Sciences Zhejiang University Key Laboratory of biomedical engineering of the Ministry of Education College of Biomedical Engineering & Instrument Science Zhejiang University

Ferroptosis, as a new type of cell death caused by lipid peroxidation, has attracted much attention since it was first identified in 2012. A lot of progress has been made in unraveling its mechanisms and therapeutic potential as a target for cancer therapy. Hitherto, there are mainly two strategies widely adopted for designing ferroptosis-inducing agents, which include increasing the intracellular reactive oxygen species(ROS) level by Fenton reaction, and inactivating the glutathione peroxidase 4(GPX4). In this mini-review,we summarize the recent advances in ferroptosis-based anticancer treatments with a highlight on nanomaterials, and discuss the current challenges faced by those agents from the perspective of in vivo applications. Moreover, by generalizing ferroptosis induced by excess iron ions to cell death caused by the polyvalent metal-mediated oxidative burden, we introduce a new paradigm of cancer treatment by exploiting various polyvalent metals to disrupt the vulnerable redox balance in cancer cells, which may greatly diversify our arsenal to combat cancer.

关键词： Ferroptosis Fenton reaction Reactive oxygen species Lipid peroxidation Glutathione peroxidase 4

A Memetic Algorithm Based Feature Weighting for Metabolomics Data Classification

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Chinese Journal of Electronics 2014年第4期23卷 706-711页

作者： ZHOU Jiarui ZHU Zexuan JI Zhen college of biomedical engineering and instrument science Zhejiang University Shenzhen City Key Laboratory of Embedded System Design College of Computer Science and Software EngineeringShenzhen University

A metaheuristic chain based memetic algorithm namely MCMA is proposed for the classification of metabolomics data. MCMA regards both global evolution and local search as equivalent elemental metaheuristics,and searches with a chain of metaheuristics performed alternatively on the target problem. A hidden Markov model based scheduling mechanism is employed in MCMA for the selection of metaheuristics. By using MCMA for optimizing the linkage weight vector, a feature weighting algorithm for metabolomics data is formed to identify relevant metabolite features and reveal their exact relationships with the given physiological states. An extreme learning machine based classifier is utilized in predicting the physiological states according to the weighted metabolite features. Experimental results on real metabolomics data of clinical liver transplantation demonstrate that the proposed feature weighting and classification method obtains better performance than the other compared algorithms.

关键词： Metabolomics Feature weighting Memetic algorithm