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State-sensitive convolutional sparse coding for potential biomarker identification in brain signals

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Science China(Information Sciences) 2024年第5期67卷 270-286页

作者： Puli WANG yu QI Gang pan College of Computer Science and Technology Zhejiang University State Key Laboratory of Brain-Machine Intelligence Zhejiang University MOE Frontier Science Center for Brain Science and Brain-machine Integration Zhejiang University Affiliated Mental Health Center & Hangzhou Seventh People's Hospital Zhejiang University School of Medicine

The identification of prototypical waveforms, such as sleep spindles and epileptic spikes, is crucial for the diagnosis of neurological disorders. These prototypical waveforms are usually recurrently presented in certain brain states, serving as potential biomarkers for clinical evaluations. Convolutional sparse coding(CSC) approaches have demonstrated strength in identifying recurrent patterns in time-series. However,existing CSC approaches do not explicitly explore state-specific patterns, making it difficult to identify state-related biomarkers. To address this problem, we propose state-sensitive CSC to learn state-specific prototypical waveforms. Specifically, we model signals of a certain state with specific waveforms that only appear frequently in this state and background waveforms that are independent of states. Based on this,state-sensitive CSC separates state-specific waveforms from background ones explicitly by incorporating incoherence constraints into optimizations. Experiments with epilepsy brain signals demonstrate that our approach can effectively identify prototypical waveforms in pre-ictal states, providing potential biomarkers for seizure prediction. Our approach provides a promising tool for automatic biomarker candidate identification.

关键词： convolutional sparse coding prototypical waveforms state-specific dictionary biomarker identification neural signal processing

Ciphertext-Only Attacks Against Compact-LWE Submitted to NIST PQC Project

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Journal of Systems Science & Complexity 2022年第3期35卷 1173-1190页

作者： LI Haoyu LIU Renzhang LIU zhen pan Yanbin XIE Tianyuan Key Laboratory of Mathematics Mechanization NCMISAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China State Key Laboratory of Cryptology Beijing 100878China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Westone Cryptologic Research Center Westone Information Industry INC.Beijing 100070China

As a candidate of the standard of post-quantum cryptography for NIST,Liu,et *** a new public-key encryption scheme Compact-LWE,whose structure is similar to LWE,but with different distribution of *** thought that the special error distribution would protect Compact-LWE from known lattice-based ***,they recommended a set of small parameters to improve the efficiency of Compact-LWE and claimed it can offer 192-bit ***,in this paper,the authors show that Compact-LWE is not secure under recommended parameters by presenting two ciphertext-only ***,the authors show that the message can be recovered efficiently from the *** the authors go further to recover an equivalent private key efficiently from the public key by exploiting the special structure of Compact-LWE.

关键词： Ciphertext-only attack Compact-LWE NIST post-quantum cryptography

Mechanism and control factors of hydrate plugging in multiphase liquid-rich pipeline flow systems: a review

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Frontiers in Energy 2022年第5期16卷 747-773页

作者： Shuwei ZHANG Liyan SHANG zhen pan Li ZHOU You GUO College of Petroleum Engineering Liaoning Petrochemical UniversityFushun 113001China College of Environmental and Safety Engineering Liaoning Petrochemical UniversityFushun 113001China College of Petrochemical Technology Liaoning Petrochemical UniversityFushun 113001China Fushun City Special Equipment Supervision and Inspection Institute Fushun 113001China

There is nothing illogical in the concept that hydrates are easily formed in oil and gas pipelines owing to the low-temperature and high-pressure environment,although requiring the cooperation of flow rate,water content,gas-liquid ratio,and other specific ***,hydrate plugging is a major concern for the hydrate slurry pipeline transportation *** order to further examine potential mechanisms underlying these processes,the present paper listed and analyzed the significant research efforts specializing in the mechanisms of hydrate blockages in the liquid-rich system,including oil-based,water-based,and partially dispersed systems(PD systems),in gathering and transportation *** addition,it summarized the influences of fluid flow and water content on the risk of hydrate blockage and *** general,flow rate was implicated in the regulation of blockage risk through its characteristic to affect sedimentation tendencies and flow *** water content can potentiate the growth of hydrates and change the oil-water dispersion degree,which causes a transition from completely dispersed systems to PD systems with a higher risk of *** of diversity of hydrate plugging mechanism in oil-based system ought to be studied in-depth by combining the discrepancy of water content and the microscopic characteristics of hydrate *** present,it is increasingly necessary to expand the application of the hydrate blockage formation prediction model in order to ensure that hydrate slurry mixed transportation technology can be more maturely applied to the natural gas industry transportation field.

关键词： hydrate flow rate water content mechanism of pipeline blockage rich liquid phase system

In vitro and in vivo studies on biodegradable magnesium alloy

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Progress in Natural Science:Materials International 2014年第5期24卷 466-471页

作者： Lida Hou zhen Li yu pan Li Du Xinlin Li yufeng zheng Li Li Center for Biomedical Materials and Engineering Harbin Engineering University Department of Materials Science and Engineering College of Engineering Peking University

The microstructure, mechanical property, electrochemical behavior and biocompatibility of magnesium alloy(Bio De MSM;) were studied in the present work. The experimental results demonstrated that grain refining induced by extrusion improves the alloy strength significantly from162 MPa for the as-cast alloy to 241 MPa for the as-extruded one. The anticorrosion properties of the as-extruded alloy also ***, the hemolysis ratio was decreased from 4.7% for the as-cast alloy to 2.9% for the as-extruded one, both below 5%. Bio De MSM;alloy shows good biocompatibility after being implanted into the dorsal muscle and the femoral shaft of the New Zealand rabbit, respectively, and there are no abnormalities after short-term implantation. In vivo observation indicated that the corrosion rate of this alloy varies with different implantation positions, with higher degradation rate in the femur than in the muscle.

关键词： Magnesium alloy Extrusion Performance Biocompatibility

First Passage Density of Brownian Motion with Two-sided Piecewise Linear Boundaries

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1505-1520页

作者： zhen yu Mao Zai TIAN Center for Applied Statistics School of StatisticsRenmin University of ChinaBeijing 100872P.R.China School of Mathematics and Data Science Changji UniversityChangji 831100P.R.China

The first passage time has many applications in fields like finance,econometrics,statistics,and ***,explicit formulas for the first passage density have only been obtained for a few *** paper derives an explicit formula for the first passage density of Brownian motion with twosided piecewise continuous boundaries which may have some points of *** are used to obtain a simplified formula for estimating the first passage ***,the results are also generalized to the case of two-sided general nonlinear *** can be easily carried out with Monte Carlo method and it is demonstrated for several typical two-sided boundaries that the proposed approximation method offers a highly accurate approximation of first passage density.

关键词： Boundary non-crossing probability first density passage density two-sided piecewise continuous boundaries Brownian motion

Effects of conductive agent type on lithium extraction from salt lake brine with LiFePO_(4) electrodes

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 678-687页

作者： zhen Zhang pan Luo Yan Zhang yuhan Wang Li Liao Bo yu Mingshan Wang Junchen Chen Bingshu Guo Xing Li School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500China Energy Storage Research Institute Southwest Petroleum UniversityChengdu 610500China

Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low ***,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines give rise to challenges,such as prolonged lithium extraction periods,diminished lithium extraction efficiency,and considerable environmental *** this work,Li FePO4(LFP)served as the electrode material for electrochemical lithium *** conductive network in the LFP electrode was optimized by adjusting the type of conductive *** approach resulted in high lithium extraction efficiency and extended cycle *** the single conductive agent of acetylene black(AB)or multiwalled carbon nanotubes(MWCNTs)was replaced with the mixed conductive agent of AB/MWCNTs,the average diffusion coefficient of Li+in the electrode increased from 2.35×10^(-9)or 1.77×10^(-9)to 4.21×10^(-9)cm^(2)·s^(-1).At the current density of 20 mA·g^(-1),the average lithium extraction capacity per gram of LFP electrode increased from 30.36 mg with the single conductive agent(AB)to 35.62 mg with the mixed conductive agent(AB/MWCNTs).When the mixed conductive agent was used,the capacity retention of the electrode after 30 cycles reached 82.9%,which was considerably higher than the capacity retention of 65.8%obtained when the single AB was ***,the electrode with mixed conductive agent of AB/MWCNTs provided good cycling *** the conductive agent content decreased or the loading capacity increased,the electrode containing the mixed conductive agent continued to show excellent electrochemical ***,a self-designed,highly efficient,continuous lithium extraction device was *** electrode utilizing the AB/MWCNT mixed conductive agent maintained excellent adsorption capacity and cycling performance in this *** work provides a new perspective for the electrochemical extraction of lithium using LFP electrodes.

关键词： salt lake brine lithium extraction electrochemical lithium extraction conductive agent extraction efficiency adsorption capacity

Synthesis and Crystal Structure of Methyl 12-Bromo-13,14-furoxan-deisopropyldehydroabietate

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Chinese Journal of Structural Chemistry 2006年第10期25卷 1209-1212页

作者： pan Ying-Ming ZHANG Ye WANG Heng-Shan CHEN zhen-Feng WU Qiang GE Chun-yu ZHANG Yong College of Chemistry and Chemical Engineering Guangxi Normal University Guilin 541004 China College of Chemistry and Chemical Engineering Suzhou University Suzhou 215006 China

Methyl 12-bromo-13,14-furoxan-deisopropyldehydroabietate, C18H22BrN2O4, has been synthesized and characterized by IR,^1H NMR, ^13C NMR and single-crystal X-ray diffraction method. It crystallizes in orthorhombic, space group P212121 with a = 6.652（2）, b = 12.832（4）, c = 20.483（6）°A, V = 1748.5（9） °A^3, Z = 4, Mr = 410.29, D, = 1.559 g/cm^3, λ= 0.71070°A, μ（MoKα） = 2.377 mm^-1, F（000） = 844, the final R = 0.0243 and wR = 0.0533 for 3780 observed reflections with I〉 2σ（I）. The C-H and bromine atom are involved in intermolecular hydrogen bonds which link the molecules into a one-dimensional chain.

关键词： methyl 12-bromo-13,14-furoxan-deisopropyldehydroabietate furoxan synthesis crystal structure

Gold nanoparticles for cancer theranostics:Abrief update

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Journal of Innovative Optical Health Sciences 2016年第4期9卷 1-10页

作者： Ning Zhao Yongxu pan zhen Cheng Hongguang Liu College of Life and Health Sciences Northeastern University ShenYangLiaoningP.R.China Department of Radiology and Bio-X Program School of Medicine Stanford UniversityStanfordCAUSA

Gold nanoparticles(AuNPs)exhibit superior optical and physical properties for more effective treatment of cancer through incorporating both diagnostic and ther apeutic functions into one single plat *** ability to passively accumulate on tumor cells provides AuNPs the oppor-tunity to become an attractive contrast agent for X-ray based computed tomography(CT)imaging in *** of facile surface modification,various size and shape of AuNPs have been extensively funct ionalized and applied as active nanoprobes and drug carriers for cancer targeted ***,their capabilities on producing photoacoustic(PA)signals and photothermal ffects have been used to image and treat tumor progression,***,we review the developments of AuNPs as cancer diagnostics and chemotherapeutic drug vector,summarizing strategies for tumor targeting and their applications in vritro and in vrivo.

关键词： Gold nanoparticles multimodal imaging phototherapy gene therapy drug delivery

Structure and flow calculation of cake layer on microfiltration membranes

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Journal of Environmental Sciences 2017年第6期29卷 95-101页

作者： Yadong yu zhen Yang yuanyuan Duan Key Laboratory for Thermal Science and Power Engineering of MOE Beijing Key Laboratory for CO2 Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

Submerged membrane bioreactors （SMBR） are widely used in wastewater treatment. The permeability of a membrane declines rapidly because of the formation of a cake layer on the membrane surface. In this paper, a multiple staining protocol was conducted to probe the four major foulants in the cake layer formed on a filtration membrane. Fluorescent images of the foulants were obtained using a confocal laser scanning microscope （CLSM）. The three dimensional structure of the cake layer was reconstructed, and the internal flow was calculated using computational fluid dynamics （CFD）. Simulation results agreed well with the experimental data on the permeability of the cake layer during filtration and showed better accuracy than the calculation by Kozeny-Carman method. B-D-Glucopyranose polysaccharides and proteins are the two main foulants with relatively large volume fractions, while a-D-glucopyranose polysaccharides and nucleic acids have relatively large specific surface areas. The fast growth of B-D-glucopyranose polysaccharides in the volume fraction is mainly responsible for the increase in cake volume fraction and the decrease in permeability. The specific area, or the aggregation/dispersion of foulants, is less important to its permeability compared to its volume fraction.

关键词： Membrane fouling CLSM Cake layer CFD Permeability