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A novel calcium phosphate-based nanocomposite for the augmentation of cement-injectable cannulated pedicle screws fixation: A cadaver and biomechanical study

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JOURNAL OF ORTHOPAEDIC TRANSLATION 2020年 20卷 56-66页

作者： Sun, Haolin liu, Chun li, xuwen liu, Huiling Zhang, Weiguang Yang, Huilin li, Chunde Yang, Lei Peking Univ Dept Orthoped Hosp 1 8 Xishiku St Beijing 100034 Peoples R China Soochow Univ Inst Orthoped Dept Orthoped Suzhou Peoples R China Peking Univ Sch Basic Med Sci Dept Human Anat 38 Xueyuan Rd Beijing 100191 Peoples R China Hebei Univ Technol Ctr Hlth Sci & Engn Sch Mat Sci & Engn Tianjin Key Lab Mat Laminating Fabricat & Interfa Tianjin Peoples R China

Background/objective: Both polymethylmethacrylate (PMMA) and traditional calcium phosphate-based cements have some deficiencies as augmentation materials for pedicle screw fixation. Here, a novel calcium phosphate-based nanocomposite (CPN) for the augmentation of pedicle screw fixation was developed based on previous study, and the handling properties, biomechanical performance, and biodegradation behaviour of CPN were evaluated and compared with clinical PMMA by means of a cadaver study and animal tests. Methods: Bone mineral density of the lumbar vertebrae was tested. Pedicle screws were placed into the lumbar vertebrae under the guidance of three dimensionally printed templates;each of which was designed based on computed tomography (CT) reconstruction of each vertebrae and augmented with either PMMA or CPN. X-ray and CT scan were used to evaluate the accuracy of screw placement and dispersion as well as interdigitation of bone cement. The axial pull-out strength and maximum torque were tested using a mechanical testing machine. Degradation behaviour of CPN was evaluated by in vitro immersion tests for 8 weeks and in vivo rabbit femur defect model for up to 6 months, respectively. Results: Standard mechanical tests revealed that PMMA was much stronger than CPN after setting (compressive strength 95 vs. 49 MPa, respectively, p < 0.001). Results of the projection area and volume distribution of cement along the distal end of the screws revealed that CPN exhibited unique dispersing and interdigitation abilities compared with PMMA. Specifically, CPN dispersed uniformly and symmetrically along the screw, while PMMA was limited to the proximal part of the screw. Axial pull-out test results showed that the axial pull-out strengths of CPN- and PMMA-augmented pedicle screws were similar (1199 +/- 225 N vs 1337 +/- 483 N, respectively) and not significantly different (p = 0.47), although CPN was an intrinsically weaker material than PMMA. Similarly, CPN showed average torq

关键词： Calcium phosphate-based cement Injectable Osteoporosis Pedicle screw PMMA

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Adaptive Temporal High-pass Infrared Non-uniformity Correction Algorithm Based on Guided Filter 2021

Adaptive Temporal High-pass Infrared Non-uniformity Correcti...

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7th International Conference on Computing and Artificial Intelligence, ICCAI 2021

作者： Zhang, Y.I. li, xuwen Zheng, Xin Wu, Qiang Beijing University of Technology Beijing China

ISBN: (纸本)9781450389501

In the scene-based infrared focal plane non-uniformity correction algorithm, the temporal high-pass filter non-uniformity correction algorithm is widely cited in various system platforms due to its low hardware platform requirements, but this algorithm is prone to "ghosting"problems and the corrected image still contains certain non-uniformity problems. To solve these problems, this paper proposes an adaptive temporal high-pass filter algorithm based on guided filter. The algorithm uses guided filter to accurately separate high-frequency components containing a large amount of fixed noise and image details, and performs image motion through adjacent frame residual images detection to determine whether to use high-frequency components for iterative operations in the temporal high-pass algorithm, and use the current image detail information to adaptively update the correction parameters of the temporal high-pass filter to avoid the accumulation of image detail information to complete the entire infrared non-uniformity correction . The algorithm in this paper uses actual infrared scene images to compare with the traditional temporal high-pass filter algorithm and bilateral filtering temporal high-pass algorithm. The results show that the algorithm proposed in this paper not only has a good correction effect, but also effectively suppresses the "ghosting"problem. © 2021 ACM.

关键词： High pass filters

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Facile approach for surfactant-free synthesis of Au@ginsenoside Rh2 nanoparticles and researches on anticancer activity

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CANCER NANOTECHNOLOGY 2022年第1期13卷 1-18页

作者： Yao, Hua Mu, Xupeng Wei, Zhenhong li, Xiuying Wu, liya Jin, Yongri li, xuwen li, Jing Jiang, Jinlan Jilin Univ Sci Res Ctr China Japan Union Hosp Changchun 130033 Peoples R China Jilin Univ Coll Chem Changchun 130021 Peoples R China

Background Inorganic nanocomposites especially Au nanostructures have exhibited outstanding physicochemical properties in biomedical fields. For further clinical applications on theranostics, especially drug delivery, numerous explorations of green and facile synthesis methods combining with pharmacoactive natural components have been investigated to construct safe and multifunctional bioactive Au nanoparticles (NPs). Ginsenoside Rh-2 is protopanaxadiol type compound isolated from plants of genus Panax, with excellent anticancer effect and antioxidant activity. In this research, we prepared the novel Au nanoparticles using ginsenoside Rh-2 as both reducing and stabilizing agents. Results The synthesized Au@ginsenoside Rh-2 NPs were proved to exhibit desirable inhibitory effect on different cancer cell lines, which benefited from the inherent anticancer effect of the ginsenoside Rh-2. Investigations in vitro indicated that Au@ginsenoside Rh-2 NPs inhibited cell proliferation, cell migration and invasion, induced cell cycle arrest, enhanced the reactive oxygen species (ROS) generation, and regulated the protein expressions of caspase-3, 8, 9 to trigger cell apoptosis as well. Conclusions Because of the absence of toxic chemical surfactants, the eco-friendly synthesis method of Au NPs modified by natural phytochemicals avoided tedious separation and modification processes. On the other hand, Au@ginsenoside Rh-2 NPs also improved water solubility and bioavailability of the hydrophobic drug ginsenoside Rh-2. It broadened minds for preparation and application of traditional Chinese medicines (TCMs) modified metal nanoparticles and deserved further study.

关键词： Ginsenoside Rh-2 Au nanoparticles Drug-modified nanocomposite Facile synthesis Anticancer activity

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A graphene modified anode to improve the performance of microbial fuel cells

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JOURNAL OF POWER SOURCES 2011年第13期196卷 5402-5407页

作者： Zhang, Yezhen Mo, Guangquan li, xuwen Zhang, Weide Zhang, Jiaqi Ye, Jianshan Huang, Xiaodan Yu, Chengzhong S China Univ Technol Sch Chem & Chem Engn Guangzhou 510641 Peoples R China Tianjin Univ Technol Sch Environm Sci & Safety Engn Tianjin 300071 Peoples R China Fudan Univ Dept Chem Shanghai 200433 Peoples R China Fudan Univ Shanghai Key Lab Mol Catalysis & Innovat Mat Shanghai 200433 Peoples R China Univ Queensland ARC Ctr Excellence Funct Nanomat Brisbane Qld 4072 Australia Univ Queensland Australian Inst Bioengn & Nanotechnol Brisbane Qld 4072 Australia

Graphene with a Brunauer similar to Emmett-Teller (BET) specific surface area of 264 m(2) g(-1) has been used as anodic catalyst of microbial fuel cells (MFCs) based on Escherichia coli (ATCC 25922). The electrochemical activities of plain stainless steel mesh (SSM), polytetrafluoroethylene (PTFE) modified SSM (PMS) and graphene modified SSM (GMS) have been investigated by cyclic voltammetry (CV), discharge experiment and polarization curve measurement. The GMS shows better electrochemical performance than those of SSM and PMS. The MFC equipped with GMS anode delivers a maximum power density of 2668 mW m(-2), which is 18 times larger than that obtained from the MFC with the SSM anode and is 17 times larger than that obtained from the MFC with the PMS anode. Scanning electron microscopy (SEM) results indicate that the increase in power generation could be attributed to the high surface area of anode and an increase in the number of bacteria attached to anode. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Graphene Biocatalyst Microbial fuel cells

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企业战略变革过程中的冲突影响研究——基于认知的视角

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系统工程理论与实践 2019年第5期39卷 1246-1255页

作者：李旭文齐中英哈尔滨工业大学管理学院哈尔滨150001 中国航天科技集团有限公司北京100048

本研究基于认知的视角,从理论上分析了企业战略变革过程中冲突的形成与影响,提出了战略变革知觉、战略变革响应与冲突关系假设模型,并开展了实证分析.研究表明,战略变革知觉与战略变革响应正相关,冲突在两者之间起到中介作用.

关键词：战略变革冲突认知

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A novel storage and extraction method using solid-phase adsorption and ultrasonic-assisted nebulization extraction coupled to solid phase extraction

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ANALYTICAL METHODS 2017年第33期9卷 4863-4872页

作者： Zhang, Peixu li, xuwen Cui, li Chen, Jiafeng Qu, Yan Wang, Xiaozhong Wu, Qian liu, Ying Zhou, Chunkui Jin, Yongri Jilin Univ Hosp 1 Dept Neurol Changchun 130031 Jilin Peoples R China Jilin Univ Coll Chem Changchun 130021 Jilin Peoples R China Jilin Women & Children Hlth Hosp Blood Bank Changchun 130021 Jilin Peoples R China

A novel storage and extraction method was developed for biofluids. Plasma spiked with four types of minor ginsenosides (Rg(2), Rg(3), Rh-1 and Rh-2) was used as a model biofluid to evaluate this method. The method was based on solid-phase adsorption and ultrasonic-assisted nebulization coupled with solid phase extraction (SPA-UANE-SPE). Diatomaceous earth was used as an adsorbent to store the plasma for long periods of time at room temperature. Ultrasonic-assisted nebulization system-solid phase extraction was used to extract the four minor ginsenosides from the plasma. Some experimental parameters, such as the type and amount of the adsorbent, the ultrasonic-assisted nebulization extraction time, the pH of the extraction solution, the concentration of ZnSO4, the amount of C-18, and the type and volume of the eluent were investigated and optimized. Under the optimized conditions, the recoveries of four minor ginsenosides were in the range of 78.5-91.4%, and the RSDs are in the range of 3.5-4.4%. For the storage stability test, the stability of the method was better than that of 4 degrees C storage and was similar to that of -20 degrees C storage. Compared with other methods, the proposed method had a better extraction performance and was advantageous in terms of ease of operation, stable long term storage, and minimal requirements for storage conditions. Thus, this method may be effective for sample preparation in biofluid analysis.

关键词： Extraction

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Selective Frustrated/Nonfrustrated Anion-Migrated Ring-Opening Polymerization of 1-Cyclopropylvinylbenzene

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MACROMOLECULES 2022年第12期55卷 5140-5148页

作者： Bai, Hongyuan Wang, Yinran Han, li Wang, Xuefei Yan, Hong li, xuwen Chen, Siwei Leng, Haitao Yao, Zijing Ma, Hongwei Dalian Univ Technol Sch Chem Engn Dept Polymer Sci & Engn Dalian 116024 Peoples R China

Exploring novel polymerization mechanisms for the preparation of switchable isomers in chains from homopolymerization with only monomers is undoubtedly an exhilarating and challenging pursuit in polymer chemistry. Therefore, this work presents a novel strategy for realizing reversible cycle anion migrated ring-opening polymerization (AMROP) and general anionic polymerization (thermodynamics limits the further ring-opening reaction of the 1-cyclopropylvinylbenzene (CPVB) unit, and this process is defined as frustrated AMROP). By employing alkali metal alkoxides (potassium tert-butoxide (t-BuOK) and sodium 2,3-dimethylpentan-3-olate (NaODP)) as additives, the opening of the cyclopropyl group in CPVB can be controlled during homopolymerization. Additionally, the structure and sequence distribution of inserted CPVB units are determined by distinct selective polymerization mechanisms. Thus, the synthetic polymer includes two structural units, i.e., ring-opened CPVB (ro), which is generated from AMROP, and nonopened CPVB (ga), which results from frustrated AMROP (F-AMROP). Furthermore, in view of steric hindrance from the penultimate-unit effect during chain growth of CPVB, the process of F-AMROP cannot continuously occur and requires the AMRO process of CPVB to decrease the steric hindrance around active centers. Therefor;under the influence of steric hindrance from the penultimate unit, AMRO, and thermodynamics, a reversible cycle of frustrated and nonfrustrated AMROP can be activated during the polymerization process, which further realizes a single monomer to prepare an alternating polymer with different isomers. Ultimately, the mechanisms for AMROP and F-AMROP are explored deeply with density functional theory calculations. This intriguing mechanistic finding will become a pioneering and innovative strategy for development of polymerization mechanisms and unprecedented polymer structures in polymer synthesis.

关键词： Additives Chemical structure Molecular structure Polymerization Polymers

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Metabolic Nanoregulators Induce Ferroptosis and Change Metabolite Flow to Reverse Immunosuppressive Tumor Microenvironment

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ACS NANO 2024年第51期18卷 34996-35012页

作者： Wang, Yu Chen, Qinjun Luo, Yifan Qu, Yangqi li, xuwen Song, Haolin li, Chufeng Zhang, Yiwen Sun, Tao Jiang, Chen Fudan Univ Key Lab Smart Drug Delivery State Key Lab Med Neurobiol Dept PharmaceutSch PharmInst Brain SciMinist Ed Shanghai 201203 Peoples R China MOE Frontiers Ctr Brain Sci Shanghai 201203 Peoples R China Fujian Med Univ Affiliated Hosp 1 Natl Reg Med Ctr Dept Digest Dis Binhai Campus Fuzhou 350212 Peoples R China

Aberrant energy and substance metabolic pathways of tumor cells critically support tumor cell proliferation by hijacking the resources from nonmalignant cells, thereby establishing a metabolite flow favorable to tumor progression. This metabolic adaptation of tumor cells further modulates the immune landscape, ultimately creating a tumor microenvironment characterized by drug resistance and immunosuppression. The synergistic regulation of energy and substance metabolic pathways might be a good antitumor therapeutic paradigm. However, due to the metabolic convergence, it is crucial to selectively modulate the aberrant metabolism of tumor cells without compromising the functionality of other cells. Small-molecule drugs have the ability to target a wide range of biomolecules for antitumor therapy, but their application is limited by undesirable toxicities. Constructing nanodrug delivery systems can improve their properties and allow for the inclusion of multiple drugs, thereby exerting synergistic antitumor effects. In this study, we developed a two-drug codelivery system using drugs-conjugated multibranched polymers to modulate tumor cell metabolism by exploiting synthetic lethal pathways for safe and effective antitumor therapy. By delivery of adapalene and erastin simultaneously through nanoparticles, the material and energy metabolism of tumor cells can be regulated. This nanoparticle construction achieves tumor tissue targeting and responsive drug release, alters metabolite flow within tumor cells, and effectively kills tumor cells. Additionally, the nanoparticles can reverse the tumor immunosuppressive microenvironment, starting from single-cell regulation to whole-lesion control.

关键词： metabolic nanoregulators metabolite flow ferroptosis immunosuppression multibranched polymers

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AN IMPROVED INTER-PREDICTION MOTION ESTIMATION ALGORITHM OF AVS

AN IMPROVED INTER-PREDICTION MOTION ESTIMATION ALGORITHM OF ...

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2nd IEEE International Conference on Broadband Network and Multimedia Technology

作者： Wu Qiang Xu Ying Jia Kebin li xuwen Beijing Univ Technol Coll Elect & Control Engn Beijing Peoples R China

ISBN: (纸本)9781424450053

Research on inter-prediction algorithms is an important respect in the real-time video codec technology. In the regarded studies, the prediction error can be reduced by incorporating high accuracy estimation and compensation algorithms. So the performance of compressed video can be improved. However, this brings a considerable cost for the complexity of encoder. The computation complexity is mainly due to the complexity of motion estimation. The paper presents an improved algorithm with the initialized searching point prediction, half-stop principle, beforehand skip mode decision, reduced search window and optional search model. This algorithm for the integer-pixel motion estimation is provided to reduce computation complexity in the block-matching process. Experimental results show that the proposed algorithm can reduce about 64%-73% of computation complexity compared to full search but only with little PSNR degradation.

关键词： AVS inter-prediction motion estimation motion vector block matching

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The Pulse Waveform and Parameters Analysis of Various Athletes Based on Radial Pulse

The Pulse Waveform and Parameters Analysis of Various Athlet...

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IEEE Workshop on Electronics, Computer and Applications (IWECA)

作者： Wang, Anran li, xuwen Yang, lin Yang, Xingxing Meng, Lanxi Su, Jun Zhang, Song Beijing Univ Technol Coll Life Sci & Bioengn Beijing 100124 Peoples R China Beijing Muxiyuan Sports Tech Sch Beijing 100075 Peoples R China

ISBN: (纸本)9781479945658

Classify the sports events by the maximal oxygen uptake (MaxO(2)) and the maximal muscular voluntary contraction (MVC). Collect the radial pulse wave of different sports events and discuss the pulse waveform and characteristic parameters. Radial pulse waveform on 304 subjects was collected, by using PowerLab and its bundled software LabChart 7, developed by ADInstrument. Normalize each radial pulse waveform and let the waveform cycle and amplitude distribute in the range of 0.100. Analyze the relative time of the maximum point Tm, the abscissa X and ordinate Y of dicrotic notch, the pulse waveform area K and the pulse wave age index SDPTG. The pulse waveform changing trend of MVC (<50%) group and MVC (>50%) group are different while the sports have the same MaxO(2). And the pulse waveform changing trend of MaxO(2) (<40%) group, MaxO(2) (40%-70%) group and MaxO(2) (>70%) group are as well as different while the sports have the same MVC.

关键词： Athlete Pulse wave Radial artery Waveform parameter

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