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Global Existence of Periodic Solutions in a Physiological Model with Delay

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Acta Mathematicae Applicatae Sinica 2015年第4期31卷 1043-1048页

作者： xiu-ling li College of Applied Mathematics Jilin University of Finance and Economics

A physiological model with delay is considered. The time delay being regarded as a parameter, a group of conditions that guarantee the model have multiple periodic solutions is obtained by the global Hopf bifurcation theorem for FDE and Bendixson＇s criterion for high-dimensional ODE. The results are illustrated by some numerical simulations.

关键词： time delay physiological model periodic solutions

Stability and Bifurcation Analysis in a System of Four Coupled Neurons with Multiple Delays

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Acta Mathematicae Applicatae Sinica 2013年第2期29卷 425-448页

作者： xiu-ling li Jun-jie WEI College of Applied Mathematics Jilin University of Finance and Economics Department of Mathematics Harbin Institute of Technology

A system of delay differential equations is studied which represent a model for four neurons with time delayed connections between the neurons and time delayed feedback from each neuron to itself. The linear stability and bifurcation of the system are studied in a parameter space consisting of the sum of the time delays between the elements and the product of the strengths of the connections between the elements. Meanwhile, the bifurcation set are drawn in the parameter space.

关键词： stability bifurcation multiple delays

Expanded Porphyrin Nanosheet for Metal-Free Photocatalytic Water Splitting Using Visible light

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Chinese Journal of Chemical Physics 2021年第3期34卷 350-355,I0046,I0048页

作者： xiu-ling li Bao-di Zhang School of Physics and Technology Nanjing Normal UniversityNanjing 210023China

Photocatalytic water splitting to generate hydrogen gas is an ideal solution for environmental pollution and unsustainable energy *** the past few decades,many efforts have been made to increase the efficiency of hydrogen *** of the most important ways is to achieve light absorption in the visible range to improve the conversion efficiency of solar energy into chemical energy,but it still presents great *** here predicted a novel organic film,which can be obtained by polymerizing HTAP molecules,as an ideal material for photocatalytic water *** on firstprinciples calculations and Born-Oppenheimer quantum molecular dynamic simulations,the metal-free two-dimensional nanomaterial has been proven to be structurally stable,with a direct band gap of 2.12 e V,which satisfies the requirement of light absorption in the visible *** importantly,the conduction bands and valence bands completely engulf the redox potentials of water,making the film be a promising photocatalyst for water *** construction method through the topological periodicity of organic molecules provides a design scheme for the photocatalyst for water splitting.

关键词： Expanded porphyrin Metal-free photocatalytic Hydrogen evolution Density functional theory

Transplantation of bone marrow-derived endothelial progenitor cells and hepatocyte stem cells from liver fibrosis rats ameliorates liver fibrosis

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World Journal of Gastroenterology 2018年第2期24卷 237-247页

作者： ling Lan Ran liu ling-Yun Qin Peng Cheng Bo-Wei liu Bing-Yong Zhang Song-Ze Ding xiu-ling li Department of Gastroenterology and Hepatology the People's Hospital of Zhengzhou University(the Henan Provincial People’s Hospital) Department of Oncology Henan Provincial Rongjun Hospital Department of Gastroenterology and Hepatology the Children’s Hospital of Zhengzhou Intensive Care Unit the Second Affiliated Hospitalof Luohe Medical College

AIM To explore the effectiveness for treating liver fibrosisby combined transplantation of bone marrow-derived endothelial progenitor cells(BM-EPCs) and bone marrow-derived hepatocyte stem cells(BDHSCs) from the liver fibrosis *** The liver fibrosis rat models were induced with carbon tetrachloride injections for 6 wk. BM-EPCs from rats with liver fibrosis were obtained by different rates of adherence and culture induction. BDHSCs from rats with liver fibrosis were isolated by magnetic bead cell sorting. Tracing analysis was conducted by labeling EPCs with PKH26 in vitro to show EPC location in the liver. Finally, BM-EPCs and/or BDHSCs transplantation into rats with liver fibrosis were performed to evaluate the effectiveness of BM-EPCs and/or BDHSCs on liver *** Normal functional BM-EPCs from liver fibrosis rats were successfully obtained. The co-expression level of CD133 and VEGFR2 was 63.9% ± 2.15%. Transplanted BM-EPCs were located primarily in/near hepatic sinusoids. The combined transplantation of BM-EPCs and BDHSCs promoted hepatic neovascularization, liver regeneration and liver function, and decreased collagen formation and liver fibrosis degree. The VEGF levels were increased in the BM-EPCs(707.10 ± 54.32) and BM-EPCs/BDHSCs group(615.42 ± 42.96), compared with those in the model group and BDHSCs group(P lirubin(TBIL), prothrombin time(PT) and activated partial thromboplastin time in the BMEPCs/BDHSCs group were significantly improved, to be equivalent to normal levels(P > 0.05) compared with those in the BDHSC(AST, TBIL and PT, P liver fibrosis(staging score of 1.75 ± 0.25 vs BDHSCs 2.88 ± 0.23 or

关键词： Bone marrow Endothelial progenitor cells liver stem cell Cell transplantation liver fibrosis

Cone-beam computed tomography noise reduction method based on U-Net with convolutional block attention module in proton therapy

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Nuclear Science and Techniques 2024年第7期35卷 89-100页

作者： Xing-Yue Ruan xiu-Fang li Meng-Ya Guo Mei Chen Ming Lv Rui li Zhi-ling Chen Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai201800China University of Chinese Academy of Sciences Beijing100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China Department of Radiation Oncology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China Shanghai Key Laboratory of Proton therapy Shanghai201801China

Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.

关键词： Proton therapy Cone-beam CT CBAM-U-Net γ-index

F-doped orthorhombic Nb_(2)O_(5) exposed with 97% (100) facet for fast reversible liþ-Intercalation

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Green Energy & Environment 2024年第4期9卷 723-731页

作者： Xiaodi liu Yufeng Tang Dan Zhang Guangyin liu Xinwei Luo Yi Shang xiu li Jianmin Ma College of Chemistry and Pharmaceutical Engineering Nanyang Normal UniversityNanyang473061China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu611731China

Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for li-ion ***,F-doped T-Nb_(2)O_(5) microﬂowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic ***,F-Nb_(2)O_(5) are assembled by single-crystal nanoﬂakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the li^(+)-intercalation ***,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical *** synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).

关键词： Exposed facets Orthorhombic Nb_(2)O_(5) F-doping Pseudocapacitive intercalation anode li-ion storage

Dynamic recrystallization mechanism, texture evolution development and mechanical characteristics of a Mg–8.7Gd–4.18Y–0.42Zr magnesium alloy by ECAP

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Progress in Natural Science:Materials International 2024年第02期34卷 376-388页

作者： ling Zhang Yinglong li School of Materials Science and Engineering Northeastern University School of Mechanical and Engineering Ningxia Institute of Science and Technology

Equal channel angle pressing is recognized for its ability to refine alloy grains and alter grain orientation, thereby achieve better mechanical performance of the magnesium alloy. This study investigates the microstructures,dynamic recrystallization mechanism, texture development, and mechanical performance of GW94K(Mg–8.7Gd–4.18Y–0.42Zr wt. %) Mg alloy following ECAP-4 passes at 400°C and 3 mm/min. Results show that when high-temperature deformation is undertaken, twin formation is suppressed while dislocation slip is facilitated, increasing dislocation density during deformation. Following ECAP deformation, the sample displayed higher fracture elongation, TYS, and UTS than the as-solutioned GW94K alloy. In particular, the GW94K alloy performed well mechanically after ECAP-4 passes, with an ultimate TYS of 231 MPa, an UTS of 290 MPa, and an elongation of 14.8 %. DDRX and shear bands induce CDRX, both of which are important in plastic deformation. as well as in modifying microstructure and grain orientation during ECAP deformation.

关键词： Dynamic recrystallization mechanism Equal channel angular pressing Magnesium alloy Mechanical performance Mg-Gd-Y-Zr alloy Texture development

Changes in the Non-targeted Metabolomic Profile of Three-year-old Toddlers with Elevated Exposure to Polycyclic Aromatic Hydrocarbons

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Biomedical and Environmental Sciences 2024年第5期37卷 479-493页

作者： li Yang liN Dan ZHANG xiu Qin JU Guang xiu SU Ya ZHANG Qian DUAN Hai Ping YU Wei Sen WANG Bing ling PANG Shu Tao Department of Epidemiology and Health Statistics School of Public HealthQingdao UniversityQingdao 266021ShandongChina Department of Environmental Health Qingdao Municipal Center for Disease Control and PreventionQingdao Institute of Preventive MedicineQingdao 266033ShandongChina Physicochemical Laboratory Qingdao Municipal Center for Disease Control and PreventionQingdao Institute of Preventive MedicineQingdao 266033ShandongChina Section of Child Health Care Huangdao Maternity and Child Health Care Hospital of QingdaoQingdao 266499ShandongChina Qingdao Blood Center Qingdao 266071ShandongChina

Objective To investigate changes in the urinary metabolite profiles of children exposed to polycyclic aromatic hydrocarbons(PAHs)during critical brain development and explore their potential link with the intestinal *** liquid chromatography-tandem mass spectrometry was used to determine ten hydroxyl metabolites of PAHs(OH-PAHs)in 36-month-old ***,37 children were categorized into low-and high-exposure groups based on the sum of the ten ***-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to identify non-targeted metabolites in the urine ***,fecal flora abundance was assessed by 16S rRNA gene sequencing using Illumina *** The concentrations of 21 metabolites were significantly higher in the high exposure group than in the low exposure group(variable importance for projection>1,Plites were positively correlated with the hydroxyl metabolites of naphthalene,fluorine,and phenanthrene(r=0.336–0.531).The identified differential metabolites primarily belonged to pathways associated with inflammation or proinflammatory states,including amino acid,lipid,and nucleotide ***,these distinct metabolites were significantly associated with specific intestinal flora abundances(r=0.34–0.55),which were mainly involved in *** Higher PAH exposure in young children affected metabolic homeostasis,particularly that of certain gut microbiota-derived *** investigation is needed to explore the potential influence of PAHs on the gut microbiota and their possible association with neurodevelopmental outcomes.

关键词： Child Gut microbiota Non-targeted metabolomics Polycyclic aromatic hydrocarbons Urinary metabolite profile

Triceps skinfold thickness trajectories and the risk of all-cause mortality:A prospective cohort study

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World Journal of Clinical Cases 2024年第15期12卷 2568-2577页

作者： Na Yang li-Yun He Zi-Yi li Yu-Cheng Yang Fan Ping ling-ling Xu Wei li Hua-Bing Zhang Yu-xiu li Department of Endocrinology Key Laboratory of Endocrinology of National Health CommissionPeking Union Medical College HospitalChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China

BACKGROUND The measurement of triceps skinfold(TSF)thickness serves as a noninvasive metric for evaluating subcutaneous fat *** its clinical utility,the TSF thickness trajectories and their correlation with overall mortality have not been thoroughly *** To explore TSF thickness trajectories of Chinese adults and to examine their associations with all-cause *** This study encompassed a cohort of 14747 adults sourced from the China Health and Nutrition *** class trajectory modeling was employed to identify distinct trajectories of TSF *** were classified into subgroups reflective of their respective TSF thickness *** utilized multivariate Cox regression analyses and mediation examinations to explore the link between TSF thickness trajectory and overall mortality,including contributory *** Upon adjustment for multiple confounding factors,we discerned that males in the‘Class 2:Thin-stable’and‘Class 3:Thin-moderate’TSF thickness trajectories exhibited a markedly reduced risk of mortality from all causes in comparison to the‘Class 1:Extremely thin’*** the mediation analyses,the Geriatric Nutritional Risk Index was found to be a partial intermediary in the relationship between TSF thickness trajectories and *** females,a lower TSF thickness pattern was significantly predictive of elevated all-cause mortality risk exclusively within the non-elderly *** In males and non-elderly females,lower TSF thickness trajectories are significantly predictive of heightened mortality risk,independent of single-point TSF thickness,body mass index,and waist circumference.

关键词： Triceps skinfold thickness Trajectory All-cause mortality Body mass index Geriatric Nutritional Risk Index