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Hydration lubrication modulated by water structure at TiO2–aqueous interfaces

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Friction 2024年第4期12卷 591-605页

作者： Pingsu ma Yuan LIU ke HAN Yu TIAN Liran ma State key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The nature of solid-liquid interfaces is of great significance in lubrication.Remarkable advances have been made in lubrication based on hydration effects.However,a detailed molecular-level understanding is still lacking.Here,we investigated water molecule behaviors at the TiO2-aqueous interfaces by the sum-frequency generation vibrational spectroscopy(SFG-VS)and atomic force microscope(AFM)to elucidate the fundamental role of solid-liquid interfaces in lubrication.Combined contributions of water structures and hydration effects were revealed,where water structures played the dominant role in lubrication for TiO2 surfaces of varying hydrophilicity,while hydration effects dominated with the increasing of ion concentrations.Superior lubrication is observed on the initial TiO2 surfaces with strongly H-bonded water molecules compared to the hydrophilic TiO2 surfaces with more disordered water.The stable ordered water arrangement with strong hydrogen bonds and the shear plane occurring between the ordered water layer and subsequent water layer may play a significant role in achieving lower friction.More adsorbed hydrated molecules with the increasing ionic concentration perturb ordered water but lead to the enhancement of hydration effects,which is the main reason for the improved lubrication for both TiO2.This work provides more insights into the detailed molecular-level understanding of the mechanism of hydration lubrication.

关键词： hydration lubrication interfacial water structures hydration effects titanium dioxide(TiO2)

MODIFIED ALTERNATING POSITIVE SEMIDEFINITE SPLITTING PRECONDITIONER FOR TIME-HARMONIC EDDY CURRENT MODELS

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Journal of Computational mathematics 2021年第5期39卷 733-754页

作者： Yifen ke Changfeng ma College of mathematics and Informatics FJKLmaA Fujian Normal UniversityFuzhou 350117China

In this paper,we consider a modified alternating positive semidefinite splitting preconditioner for solving the saddle point problems arising from the finite element discretization of the hybrid formulation of the time-harmonic eddy current model.The eigenvalue distribution and an upper bound of the degree of the minimal polynomial of the preconditioned matrix are studied for both simple and general topology.Numerical results demonstrate the effectiveness of the proposed preconditioner when it is used to accelerate the convergence rate of Krylov subspace methods such as GMRES.

关键词： Time-harmonic eddy current model Saddle point problem Eigenvalue distribution Preconditioner

Buyang Huanwu Decoction Ameliorates Damage of Erectile Tissue and Function Following Bilateral Cavernous Nerve Injury

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Chinese Journal of Integrative Medicine 2023年第9期29卷 791-800页

作者： YE Miao-yong ZHAO Fan MA Ke YAO Li-juan ZHOU Kang ma Jian-xiong LYU Bo-dong XU Zeng-bao Department of Urology the First People’s Hospital of WenlingWenlingZhejiang Province317500China Department of Urology Affiliated Hospital of Nantong UniversityNantongJiangsu Province226001China The Second Clinical Medical College Zhejiang Chinese Medical UniversityHangzhou310053China Department of Urology Huzhou Hospital of Traditional Chinese MedicineHuzhouZhejiang Province313000China Andrology Laboratory on Integration of Chinese and Western Medicine Zhejiang Provincial Key Laboratory of Traditional Chinese MedicineHangzhou310053China

Objective To verify the effect of Buyang Huanwu Decoction(BHD)in ameliorating erectile dysfunction(ED)after radical prostatectomy(RP).Methods The composition of BHD was verified by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry(UPLC-QTOF-MS/MS)analysis.Bilateral cavernous nerve crush injury(BCNI)in rats was used to mimic the neurovascular injury occurring after RP.By the envelope method,forty rats were randomly divided into 4 groups as follows:sham(cavernous nerves exposed only),model(BCNI),low-dosage BHD[LBHD,12.8 g/(kg·d)],and high-dosage BHD[HBHD,51.2 g/(kg·d)]groups,10 rats in each group,feeding for 3 weeks respectively.Erectile function was evaluated by measuring intracavernosal pressure(ICP).Changes in the histopathology of corpus cavernosum(CC)were examined by hematoxylin-eosin staining.Meanwhile,the fibrosis of CC was measured by masson’s trichrome staining and Western blot was used to detect the expressions of collagen I,transforming growth factor beta 1(TGF-β1)andα-smooth muscle actin(α-Sma).Apoptosis index was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL)and Western blot for determining the expressions of B-cell lymphoma 2(Bcl-2)and Bcl-2-associated X(Bax).The oxidative stress in the CC were assessed by the superoxide dismutase(SOD),malondialdehyde(MDA)and reactive oxygen species(ROS)levels.The proteins expression of c-Jun N-terminal kinase(JNK)and c-Jun were detected by Western blot.In addition,the expression ofα-Sma and p-c-Jun in the CC was observed by double immunofluorescence staining.Results The UPLC-QTOF-MS/MS analysis showed that BHD contained calycosin-7-O-β-D-glucoside,ononin,calycosin and formononetin.Compared with the model group,LBHD and HBHD treatment improved the ICP and the circumference,area,and weight of CC(Pma and Bcl

关键词： Buyang Huanwu Decoction erectile dysfunction cavernous nerve injury Chinese medicine Jun N-terminal kinase

macrophages’M1 or M2 by tumor microparticles:lysosome makes decision

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Cellular & Molecular Immunology 2022年第10期19卷 1196-1197页

作者： ke Tang Jingwei ma Bo Huang Department of Biochemistry and Molecular Biology Tongji Medical CollegeHuazhong University of Science and Technology430030WuhanChina Cell Architecture Research Center Huazhong University of Science and Technology430030WuhanChina Department of Immunology Tongji Medical CollegeHuazhong University of Science and Technology430030WuhanChina Department of Immunology&National key Laboratory of Medical Molecular Biology Institute of Basic Medical SciencesChinese Academy of Medical Sciences(CAMS)&Peking Union Medical College100005BeijingChina

Cells deliver messages to their surroundings or distant cells by secreting signaling molecules or releasing extracellular microvesicles(EVs)[1,2].Two types of EVs have been identified:exosomes and microparticles(MPs),which are also termed microvesicles(MVs).Exosomes are endosome-derived EVs(30-100 nm)that deliver information about proteins,mRNAs,and microRNAs to recipient cells[3].MPs are plasma membrane-derived shedding vesicles with sizes ranging from 0.1 to 1μm[4].

关键词： releasing sizes deliver

The combination of EGCG with warfarin reduces deep vein thrombosis in rabbits through modulating HIF-1αand VEGF via the PI3K/AKT and ERK1/2 signaling pathways

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Chinese Journal of Natural Medicines 2022年第9期20卷 679-690页

作者： LI Yan GE Jing-Ping MA Ke YIN Yuan-Yuan HE Juan GU Jian-Ping Department of Vascular and Interventional Radiology Nanjing First HospitalNanjing Medical UniversityNanjing 210006China Department of Acupuncture Qinhuai District Hospital of Traditional Chinese MedicineNanjing 210000China

Deep venous thrombosis(DVT)poses a major challenge to public health worldwide.Endothelial cell injury evokes inflammatory and oxidative responses that contribute to thrombus formation.Tea polyphenol(TP)in the form of epigallocatechin-3-gallate(EGCG)has anti-inflammatory and oxidative effect that may ameliorate DVT.However,the precise mechanism remains incompletely understood.The current study was designed to investigate the anti-DVT mechanism of EGCG in combination with warfarin(an oral anticoagulant).Rabbits were randomly divided into five groups.A DVT model of rats was established through ligation of the inferior vena cava(IVC)and left common iliac vein,and the animals were orally administered with EGCG,warfarin,or vehicle for seven days.In vitro studies included pretreatment of human umbilical vein endothelial cells(HUVECs)with different concentrations of EGCG for 2 h before exposure to hydrogen peroxide.Thrombus weight and length were examined.Histopathological changes were observed by hematoxylin-eosin staining.Blood samples were collected for detecting coagulation function,including thrombin and prothrombin times,activated partial thromboplastin time,and fibrinogen levels.Protein expression in thrombosed IVCs and HUVECs was evaluated by Western blot,immunohistochemical analysis,and/or immunofluorescence staining.RT-qPCR was used to determine the levels of AGTR-1 and VEGF mRNA in IVCs and HUVECs.The viability of HUVECs was examined by CCK-8 assay.Flow cytometry was performed to detect cell apoptosis and ROS generation was assessed by 2′,7ʹ-dichlorofluorescein diacetate reagent.In vitro and in vivo studies showed that EGCG combined with warfarin significantly reduced thrombus weight and length,and apoptosis in HUVECs.Our findings indicated that the combination of EGCG and warfarin protects HUVECs from oxidative stress and prevents apoptosis.However,HIF-1αsilencing weakened these effects,which indicated that HIF-1αmay participate in DVT.Furthermore,HIF-1αsilencing significantly up-regulated cell apoptosis and

关键词： Deep vein thrombosis EGCG Warfarin HIF-1α VEGF PI3K/AKT ERK1/2

Role of bimodal-grained structure with random texture on mechanical and corrosion properties of a Mg-Zn-Nd alloy

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Journal of magnesium and Alloys 2022年第8期10卷 2147-2157页

作者： Ming Gao ke Yang Lili Tan Zheng ma School of materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Shi-changxu Innovation Center for advanced materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

Fine grained ZN20 alloy was obtained by combining equal-channel angular pressing(ECAP)with extrusion.Microstructural observation showed an obvious grain refinement with an average grain size of 10μm after ECAP.The original bimodal-grained structure composed of coarse grains with strong basal texture and fine grains with random texture was substituted by a new kind of bimodal-grained structure with finer grains and more random texture after 4 passes ECAP at 300℃.The combination of grain refinement and texture weakening caused the ductility can be increased by 40%compared with the as-extruded alloy.Immersion test in simulated intestinal fluid revealed an improvement of corrosion resistance after ECAP.Grain refinement can stable the corrosion product layer and basal texture is more beneficial for the corrosion resistance than the non-basal texture.

关键词： magnesium ECAP Bimodal-grained structure Corrosion resistance Mechanical property

An adaptive sequential experiment design method for model validation

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Chinese Journal of Aeronautics 2020年第6期33卷 1661-1672页

作者： ke FANG Yuchen ZHOU Ping ma Control and Simulation Center Harbin Institute of TechnologyHarbin 150080China

Efficient experiment design is of great significance for the validation of simulation model with high nonlinearity and large input space.Excessive validation experiment raises the cost while insufficient test increases the risks of accepting an invalid model.In this paper,an adaptive sequential experiment design method combining global exploration criterion and local exploitation criterion is proposed.The exploration criterion utilizes discrepancy metric to improve the space-filling property of the design points while the exploitation criterion employs the leave one out error to discover informative points.To avoid the clustering of samples in the local region,an adaptive weight updating approach is provided to maintain the balance between exploration and exploitation.Besides,the credibility distribution function characterizing the relationship between the input and result credibility is introduced to support the model validation experiment design.Finally,six benchmark problems and an engineering case are applied to examine the performance of the proposed method.The experiments indicate that the proposed method achieves satisfactory performance for function approximation in accuracy and convergence.

关键词： Adaptive sequential experiment design Credibility distribution function Gaussian process model Metamodeling Model validation

Are public‒private partnerships still an answer for social infrastructure?A systematic literature review

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工程管理前沿:英文版 2023年第3期10卷 467-482页

作者： Liang ma Yangyang HU Liuying ZHU Yongjian ke School of management Shanghai UniversityShanghai 200444China Institute of Regional and Urban Development of Shanghai University Shanghai 200444China School of Built Environment University of Technology SydneySydney 2007Australia

Social infrastructure has become an important element for measuring national economic development and social benefits that are usually financed in the form of government grants,private investment,and public‒private partnerships(PPPs).However,social infrastructure PPPs have attracted considerable public debate due to their low profitability and complex operational demands.This study aims to answer the question,“are PPPs still an answer for social infrastructure?”,from the perspectives of the body of knowledge,application status,and prospects.Initially,an iterative search and review procedure and a scientometric analysis were performed to systematically screen the literature and to structure the body of knowledge of the social infrastructure PPPs literature.Furthermore,the application status and trends were analyzed to further explore the studied countries/regions,application sectors,and research topics.Results show that PPPs still have valuable application potential for delivering social infrastructure despite their mixed results across different topics.Six main research themes and the corresponding research trends were also identified,namely,financing and economics viability,risk management,performance management,contract and relationship management,governance and regulation,and facilitating and hindering factors.These findings offer practitioners and researchers a comprehensive overview and constructive guidance on social infrastructure PPPs.

关键词： public‒private partnerships social infrastructure scientometric analysis systematic review

Iridium single-atom catalyst for highly efficient NO electroreduction to NH_(3)

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Nano Research 2023年第7期16卷 8737-8742页

作者： Kai Chen Guohui Wang Yali Guo Dongwei ma ke Chu School of materials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China key Laboratory for Special Functional materials of Ministry of Education School of Materials Science and EngineeringHenan UniversityKaifeng 475004China

Atomically dispersed Ir confined in amorphous MoO_(3)(Ir1/a-MoO_(3))was designed as a high-efficiency catalyst for electrochemical reduction reaction of NO to NH_(3)(NORR).Atomic precise characterizations reveal that isolated Ir atoms are immobilized in Ovacancies of amorphous MoO_(3) to form Ir_(1)-O_(5) moieties.Theoretical computations demonstrate that single-site Ir1-O5 can not only powerfully activate and hydrogenate NO with a near-zero energy barrier,but also exhibit a higher affinity to NO over H adatoms to suppress the competing hydrogen evolution and promote both NORR activity and selectivity.Consequently,Ir_(1)/a-MoO_(3) shows the maximum NH_(3)yield rate of 438.8μmol·h^(-1)·cm^(-2) and NH_(3)-Faradaic efficiency of 93.2%,representing one of the most efficient NORR catalysts to date.

关键词： electrochemical reduction of NO to NH_(3) single-atom catalysts amorphous materials theoretical calculations