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Mechanical behavior of the erythrocyte in microvessel stenosis

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Science China(Life Sciences) 2011年第5期54卷 450-458页

作者： zhang zhiguo zhang XiWen State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China School of Aerospace Tsinghua University Beijing 100084 China

The passage of red blood cells （RBCs） through capillaries is essential for human blood microcirculation. This study used a moving mesh technology that incorporated leader-follower pairs to simulate the fluid-structure and structure-structure interac- tions between the RBC and a microvessel stenosis. The numerical model consisted of plasma, cytoplasm, the erythrocyte membrane, and the microvessel stenosis. Computational results showed that the rheology of the RBC is affected by the Reynolds number of the plasma flow as well as the surface-to-volume ratio of the erythroeyte. At a constant inlet flow rate, an increased plasma viscosity will improve the transit of the RBC through the microvessel stenosis. For the above reasons, we consider that the decreased hemorheology in microvessels in a pathological state may primarily be attributed to an increase in the number of white blood cells. This leads to the aggregation of RBCs and a change in the blood flow structure. The present fundamental study of hemorheology aimed at providing theoretical guidelines for clinical hemorheology.

关键词： red blood cell moving mesh leader-follower pair rheology fluid-structure interaction

Weak Graph Map Homotopy and Its Applications

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 235-252页

作者： Conglei zhang Yanying WANG zhiguo zhang Yan ZHAO School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024China Department of Basic Science Shanxi Agricultural UniversityJinzhang 030801ShanxiChina Center for Topology and Geometry based Technology School of Mathematical SciencesHebei Normal UniversityShijiazhuang 050024China School of Mathematical Sciences Hebei Normal UniversityTaiyuan 030031China School of Mathematics and Computer Science Shanxi Normal UniversityShijiazhuang 050024China School of Mathematics and Science Hebei GEO UniversityShijiazhuang 050031China

The authors introduce a notion of a weak graph map homotopy(they call it M-homotopy),discuss its properties and *** prove that the weak graph map homotopy equivalence between graphs coincides with the graph homotopy equivalence defined by Yau et al in *** difference between them is that the weak graph map homotopy transformation is defined in terms of maps,while the graph homotopy transformation is defined by means of combinatorial *** discuss its advantages over the graph homotopy *** its applications,they investigate the mapping class group of a graph and the 1-order M P-homotopy group of a pointed simple ***,they show that the 1-order M P-homotopy group of a pointed simple graph is invariant up to the weak graph map homotopy equivalence.

关键词： Weak graph map homotopy Trivial vertex Strong deformation retract Mapping class group MP-Homotopy group

Histones, histone chaperones and nucleosome assembly

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Protein & Cell 2010年第7期1卷 607-612页

作者： Rebecca J.Burgess zhiguo zhang Department of Biochemistry and Molecular Biology Mayo Clinic College of Medicine200 First Street SWRochesterMN 55905USA

Chromatin structure governs a number of cellular processes including DNA replication,transcription,and DNA *** DNA replication,chromatin structure including the basic repeating unit of chromatin,the nucleosome,is temporarily disrupted,and then reformed immediately after the passage of the replication *** coordinated process of nucleosome assembly during DNA replication is termed replication—coupled nucleosome *** of this process can lead to genome instability,a hallmark of cancer ***,addressing how replication-coupled nucleosome assembly is regulated has been of great ***,we review the current status of this growing field of interest,highlighting recent advances in understanding the regulation of this important process by the dynamic interplay of histone chaperones and histone modifications.

关键词： nucleosome chaperones assembly

A strategy to achieve high loading and high energy density Li-S batteries

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Journal of Energy Chemistry 2021年第2期30卷 340-346,I0012页

作者： Fei Yin Qi Jin Hong Gao XiTian zhang zhiguo zhang Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of ducationSchool of Physics and Electronic Engineering Harbin Normal tnivrstyHarbin 150025HeilongjiangChina Condensed Mater Science and Technology Institute Department of PhysicsHarbin lustitute of TechnologyHarbin 15001Helongiang China

Lithium-sulfur(Li-S) batteries are one of the most promising rechargeable storage devices due to the high theoretical energy ***,the low areal sulfur loading impedes their commercial ***,a 3 D free-standing sulfur cathode scaffold is rationally designed and fabricated by coaxially coating polar Ti_3 C_2 T_x flakes on sulfur-impregnated carbon cloth(Ti_3 C_2 T_x@S/CC) to achieve high loading and high energy density Li-S batteries,in which,the flexible CC substrate with highly porous structure can accommodate large amounts of sulfur and ensure fast electron transfer,while the outer-coated Ti_3 C_2 T_x can serve as a polar and conductive protective layer to further promote the conductivity of the whole electrode,achieve physical blocking and chemical anchoring of lithium-polysulfides as well as catalyze their *** to these advantages,at a sulfur loading of 4 mg cm^(-2),Li-S cells with Ti_3 C_2 T_x@S/CC cathodes can deliver outstanding cycling stability(746.1 mAh g^(-1) after 200 cycles at1 C),superb rate performance(866.8 mAh g^(-1) up to 2 C) and a high specific energy density(564.2 Wh kg^(-1) after 100 cycles at 0.5 C).More significantly,they also show the commercial potential that can compete with current lithium-ion batteries due to the high areal capacity of 6.7 mAh cm^(-2) at the increased loading of 8 mg cm^(-2).

关键词： Lithium-sulfur batteries High energy density Ti_(3)C_(2)T_(x) High sulfur loading 3D free-standing sulfur cathode

Kinetics process of room temperature phosphorescence and fluorescence of gadolinium porphyrin in aqueous solution

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Journal of Rare Earths 2021年第10期39卷 1187-1193,I0001页

作者： Ting Liu Xiyu zhang Honglin zhang Hua Zhao zhiguo zhang Ye Tian Condensed Matter Science and Technology Institute Harbin Institute of TechnologyHarbin 150001 China School of Materials and Engineering Harbin Institute of TechnologyHarbin 150001China Division of Cardiology The First Affiliated HospitalHarbin Medical UniversityHarbin 150001China

The behavior of room temperature phosphorescence quenching and fluorescence enhancing of gadolinium labeled sinoporphyrin sodium(Gd-DVDMS) in the aqueous solution were ***-DVDMS was characterized by various techniques including mass spectra,Fourier transform infrared spectra and transmission electron *** optical behavior was monitored through UV-vis absorption spectra and photoluminescence *** result shows that the phosphorescence intensity gradually quenches,almost disappears after dissolved 120 min,meanwhile the fluorescence intensity enhances 5 *** above behavior is attributed to the decreased population of Gd-DVDMS as first excited triplet state(T1),Based on the time-invariant of both absorption spectra and phosphorescence decay curves at710 nm of Gd-DVDMS in different dissolution time,the reason for the decreased population of GdDVDMS in T1 state is that the intersystem crossing from first excited state(S1) to T1 is *** addition,the fluorescent decay curves of Gd-DVDMS initially dissolved in the aqueous solution and dissolved for 120 min were also measured for *** big change in fluorescent lifetime further proves the conclusion that intersystem crossing is prevented,meanwhile,the increase in fluorescence intensity is *** this work,the possibility of decomposition of Gd-DVDMS is excluded because the phosphorescence decay curve in Gd-DVDMS aqueous solution is sensible to DVDMS.

关键词： Gd-DVDMS Phosphorescence Fluorescence Aqueous solution Intersystem crossing Rare earths

In-situ growth of nanowire WO_(2.72) on carbon cloth as a binder-free electrode for flexible asymmetric supercapacitors with high performance

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Journal of Energy Chemistry 2019年第2期28卷 58-64页

作者： Xiao Huang zhiguo zhang Huan Li Hongxia Wang Tingli Ma Department of Life Science and System Engineering Kyushu Institute of Technology School of Chemistry Physics and Mechanical EngineeringQueensland University of Technology School of Petroleum and Chemical Engineering Dalian University of Technology

For the first time,WO_(2.72) nanowires were in-situ grown on carbon cloth by a simple solvothermal *** nanowire WO_(2.72)/carbon cloth(NW WO_(2.72)/CC) electrode showed good electrochemical performance with specific capacitance(C_s) reaching up to 398 F g^(-1) at a current density of 2 A g^(-1).The capacitance of 240 F g^(-1) was retained at a high current density of 16 A g^(-1).To further evaluate the energy storage performance,flexible asymmetric supercapacitors(FASC_s) were fabricated using the activated carbon/carbon cloth(AC/CC) as negative electrode and NW WO_(2.72)/CC as positive electrode,*** FASC_s delivered a high energy density of 28 Wh kg^(-1) at a power density of 745 W kg^(-1) and 13 Wh kg^(-1) even at a high power density of 22.5 k W kg^(-1).More impressively,81% of the specific capacitance of the FASC_s was retained after 10,000 cycles,indicating excellent cycle *** work indicates the NW WO_(2.72)/CC holds a great potential for application in energy storage devices.

关键词： Solvothermal reaction Asymmetric supercapacitors High energy density Flexibility

Determining the Critical Fracture Stress of Al Dendrites near the Melting Point via Synchrotron X-ray Imaging

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Acta Metallurgica Sinica(English Letters) 2023年第5期36卷 857-864页

作者： Ling Qin zhiguo zhang Baisong Guo Wei Li Jiawei Mi Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou510632China Department of Engineering University of HullEast YorkshireHU67RXUK Center of Innovation for Flow Through Porous Media Department of Petroleum EngineeringUniversity of WyomingLaramieWY82071USA Department of Materials University of OxfordOxfordOX13PHUK

Dendrites are the most common microstructural features in the cast metals,significantly affecting the structure integrity and mechanical properties of the *** this study,the in situ synchrotron X-ray radiographic and tomographic imaging techniques were combined to evaluate the critical fracture stress of the growing dendrite tip during the solidification of an Al-15 wt%Cu alloy under an external electromagnetic *** dendritic 3D models have been proposed to simulate the dendrite 3D morphologic characteristics and thus revealed that the critical fracture stresses of the Al dendrites at temperatures close to its melting point were in the range of 0.5 kPa–0.05 *** present results demonstrate the feasibility of measuring the high-temperature mechanical properties of the metallic dendrites.

关键词： Synchrotron X-ray radiography Tomography Al dendrite Fragmentation Critical fracture stress

Flavonoids of Rosa rugosa *** tumor proliferation and metastasis in human hepatocellular carcinoma HepG2 cells

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Food Science and Human Wellness 2022年第2期11卷 374-382页

作者： zhiguo zhang Meilin Wang Shu Xing Chen zhang School of Food Science and Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China School of Chemistry and Pharmaceutical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China School of Science The Hong Kong University of Science and TechnologyHong KongChina

Rosa rugosa *** recognized as both medicine and edible in *** article investigated the antitumor activity of rose ***-extracted rose flavonoids(RFW)and ethanol-extracted rose flavonoids(RFE)were achieved by extracting with distilled water and 70%ethanol,*** effects of the two extracts on proliferation inhibition,apoptosis inducement and metastasis prevention of human HepG2 hepatocellular carcinoma cell lines were tested,via optical/fluorescence microscopy,MTT detection,Transwell assay,flow cytometry and Western blot,*** results indicated that rose flavonoids at low concentration(10-40μg/mL)had a better inhibitory effect on migration and invasion of HepG2 cells in a dose-dependent manner,while rose flavonoids at high concentration(80-160μg/mL)could induce apoptosis of HepG2 cells by up-regulating the expression of pro-apoptotic proteins p53 and Bax,and down-regulating the expression of anti-apoptotic proteins Bcl-2,leading to the functioning of caspase-3 and *** effect of RFE at the same concentration was significantly better than that of ***,this study found that rose flavonoids had a certain inhibitory effect on proliferation and metastasis of human liver cancer cells HepG2,indicating the application of rose flavonoids in preventing and treating of liver cancer.

关键词： Rose flavonoids Tumor metastasis Apoptosis Human liver cancer

Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

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China Foundry 2013年第6期10卷 374-379页

作者： zhang Peng Zeng Shaolian zhang zhiguo Li Wei Department of Materials Science and Engineering Jinan University Engineering Research Center of Wear Resistant Materials Jinan University

In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry(EDS), electron probe microanalysis(EPMA), scanning electron microscope(SEM) and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle volumetric fraction of ～38%. During solidification, interface reaction takes place between WC-Co particles and high chromium cast iron. Melting and dissolving of prefabricated particles are also found, suggesting that local Co melting and diffusion play an important role in promoting interface metallurgical bonding. The composite layer is composed of ferrite and a series of carbides, such as(Cr, W, Fe)23C6, WC, W2C, M6C and M12C. The inhomogeneous hardness in the obtained composite material shows a gradient decrease from the particle reinforced metal matrix composite layer to the matrix layer. The maximum hardness of 86.3 HRA(69.5 HRC) is obtained on the particle reinforced surface, strongly indicating that the composite can be used as wear resistant material.

关键词： particle reinforcement infiltration casting composite material high Cr cast iron hardness