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Ruin Probabilities for a Two-Dimensional Perturbed Risk Model with Stochastic Premiums

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Acta Mathematicae Applicatae Sinica 2016年第4期32卷 1053-1066页

作者： Jian-hua cheng De-hui WANG School of Mathematics Jilin University

In this paper, we consider a two-dimensional perturbed risk model with stochastic premiums and certain dependence between the two marginal surplus processes. We obtain the Lundberg-type upper bound for the infinite-time ruin probability by martingale approach, discuss how the dependence affects the obtained upper bound and give some numerical examples to illustrate our results. For the heavy-tailed claims case, we derive an explicit asymptotic estimation for the finite-time ruin probability.

关键词： two-dimensional risk model ruin probability upper bound dependent risk asymptotic estimate

Hemodynamic effects of stenting on wide-necked intracranial aneurysms

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Chinese Medical Journal 2010年第15期123卷 1999-2003页

作者： ZHANG Yi-sen YANG Xin-jian WANG Sheng-zhang QIAO Ai-ke CHEN Jia-liang ZHANG Kun-ya LIU Zhi-cheng ZHAO Yu-jing ZHANG Ying LUO bin LI Chuan-hui Department of Interventional Neuroradiology Beijing Neurosurgical Institute Capital Medical University Beijing 100050 China Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China College of Life Science and Bioengineering Beijing University of Technology Beijing 100024 China Department of Biomedical Engineering Capital Medical University Beijing 100050 China Department of Biomedical Engineering Capital Medical University Beijing 100050 China

Background Stent placement has been widely used to assist coiling in cerebral aneurysm treatments. The present study aimed to investigate the hemodynamic effects of stenting on wide-necked intracranial *** Three idealized plexiglass aneudsmal models with different geometries before and after stenting were created, and their three-dimensional computational models were constructed. Flow dynamics in stented and unstented aneurismal models were studied using in vitro flow visualization and computational fluid dynamics （CFD） simulations. In addition, effects of stenting on flow dynamics in a patient-specific aneurysm model were also analyzed by *** The results of flow visualization were consistent with those obtained with CFD simulations. Stent deployment reduced vortex inside the aneurysm and its impact on the aneurysm sac, and decreased wall shear stress on the *** aneurysm geometries dictated fundamentally different hemodynamic patterns and outcomes of *** Stenting across the neck of aneurysms improves local blood flow profiles. This may facilitate thrombus formation in aneurysms and decrease the chance of recanalization.

关键词： intracranial aneurysm stents hemodynamics computational fluid dynamics

Association of time-varying changes in physical activity with cardiac death and all-cause mortality after ICD or CRT-D implantation

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Journal of Geriatric Cardiology 2022年第3期19卷 177-188页

作者： Xue-Rong SUN Chen-Di cheng bin ZHOU Shuang ZHAO Ke-Ping CHEN Wei HUA Yan-Gang SU Wei XU Fang WANG Xiao-Han FAN Yan DAI Zhi-Min LIU Shu ZHANG Arrhythmia Center State Key Laboratory of Cardiovascular DiseaseFuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Department of Cardiology Laboratory of Heart CenterZhujiang HospitalSouthern Medical UniversityGuangzhouChina Department of Cardiology Shanghai Institute of Cardiovascular DiseasesZhongshan HospitalFudan UniversityShanghaiChina Department of Cardiology Nanjing Drum Tower HospitalNanjingChina Department of Cardiology Shanghai First People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

OBJECTIVE To evaluate the association of longitudinal changes in physical activity(PA)with long-term outcomes after im-plantable cardioverter-defibrillator(ICD)or cardiac resynchronization therapy defibrillator(CRT-D)*** Patients with ICD/CRT-D implantation from SUMMIT registry were retrospectively ***-de-rived PA changes over 12 months post implantation were obtained from the archived home monitoring *** primary end-points were cardiac death and all-cause *** secondary endpoints were the first ventricular arrthymia(VA)and first ap-propriate ICD *** In 705 patients,446(63.3%)patients showed improved PA over 12 months after *** a mean 61.5-month follow-up duration,99 cardiac deaths(14.0%)and 153 all-cause deaths(21.7%)*** to reduced/un-changed PA,improved PA over 12 months could result in significantly reduced risks of cardiac death(improved PA≤30 min:hazard ratio(HR)=0.494,95%CI:0.288−0.848;>30 min:HR=0.390,95%CI:0.235−0.648)and all-cause mortality(improved PA≤30 min:HR=0.467,95%CI:0.299−0.728;>30 min:HR=0.451,95%CI:0.304−0.669).No differences in the VAs or ICD shocks were observed across different groups of PA *** changes can predict the risks of cardiac death only in the low baseline PA group,but improved PA was associated with 56.7%,57.4%,and 62.3%reduced risks of all-cause mortality in the low,moderate,and high baseline PA groups,respectively,than reduced/unchanged *** Improved PA could protect aganist cardiac death and all-cause mortality,probably reflecting better clinical efficacy after ICD/CRT-D ***-intensity exercise training might be encouraged among patients with different baseline PA levels.

关键词： cardiac mortality implantation

Breast Cancer Resistance Protein Expression and 5-Fluorouracil Resistance

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Biomedical and Environmental Sciences 2008年第4期21卷 290-295页

作者： JIAN-HUI YUAN JIN-QUAN cheng LONG-YUAN JIANG WEI-DONG JI liang-FENG GUO JIAN-JUN LIU XING-YUN XU JING-SONG HE XIAN-MING WANG ZHI-XIONG ZHUANG Faculty of Preventive Medicine School of Public Health Sun Yat-Sen University Guangzhou 510080Guangdong China Toxicology Laboratory Municipal Center for Disease Control and PreventionShenzhen 518020 Guangdong China Department of Emergency The Second Affiliated Hospital of Sun Yat-Sen University Guangzhou 510120 Guangdong China Department of General Surgery Shenzhen Second People＇s Hospital Shenzhen 518035 Guangdong China

Objective To filtrate breast cancer resistance protein （BCRP）-mediated resistant agents and to investigate clinical relationship between BCRP expression and drug resistance. Methods MTT assay was performed to filtrate BCRP-mediated resistant agents with BCRP expression cell model and to detect chemosensitivity of breast cancer tissue specimens to these agents. A high performance liquid chromatography （HPLC） assay was established, and was used to measure the relative dose of intracellular retention resistant agents. RT-PCR and immunohistochemistry （IHC） were employed to investigate the BCRP expression in breast cancer tissue specimens. Results MTT assay showed that the expression of BCRP increased with the increasing resistance of 5-fluorouracil （5-Fu）（P〈0.05, n=3） in the cell model, while HPLC assay indicated that the intracellular retention dose of 5-Fu was significantly correlated with the expression of BCRP （t=-0.897, P〈0.05, n=3）. A total of 140 breast cancer tissue specimens were collected. BCRP-positive expression was detected in forty-seven specimens by both RT-PCR and IHC. As shown by MTT assay subsequently, the resistance index （RI） of 47 BCRP-positive breast cancer tissue specimens to 5-Fu was 7-12 times as high as that of adjacent normal tissue samples. BCRP expression was related to 5-Fu resistance （R2=0.8124, P〈0.01）. Conclusion Resistance to 5-Fu can be mediated by BCRR Clinical chemotherapy for breast cancer patients can be optimized based on BCRP-positive expression.

关键词： Breast cancer resistance protein 5-fluorouracil Breast cancer Resistance Chemotherapy

Manganese molybdate nanodots with dual amplification of STING activation for“cycle”treatment of metalloimmunotherapy

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Bioactive Materials 2024年第1期31卷 53-62页

作者： Huali Lei Quguang Li Guangqiang Li Tianyi Wang Xinjing Lv Zifan Pei Xiang Gao Nailin Yang Fei Gong Yuqi Yang Guanghui Hou Minjiang Chen Jiansong Ji Zhuang Liu liang cheng Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhou215123China Department of Neurosurgery The First Affiliated Hospital of Soochow UniversitySuzhou215000China Children’s Hospital of Soochow University Pediatric Research Institute of Soochow UniversitySuzhou215123China Department of Orthopedics The Second Affiliated Hospital of Soochow UniversitySuzhouJiangsu215004China Key Laboratory of Imaging Diagnosis and Minimally Invasive Intervention Research Fifth Affiliated Hospital of Wenzhou Medical UniversityLishui323000ZhejiangChina

Certain types of cationic metal ions,such as Mn^(2+)are able to activate immune functions via the stimulator of interferon genes(STING)pathway,showing potential applications in eliciting antitumor *** anionic ions interact with immune cells remains largely ***,selecting from a range of cationic and anionic ions,we were excited to discover that MoO_(4)^(2-)could act as a cGAS-STING agonist and further confirmed the capability of Mn^(2+)to activate the cGAS-STING *** by such findings,we synthesized manganese molybdate nanoparticles with polyethylene glycol modification(MMP NDs)for cancer ***,MMP NDs could consume glutathione(GSH)over-expressed in tumors and induce ferroptosis owing to high-valence Mo and Mn to elicit tumor-specific immune responses,which was further amplified by MMP-triggered the cGAS-STING *** turn,activated CD8+T cells to secrete high levels of interferonγ(IFN-γ)and reduced GPX4 expression in tumor cells to trigger ferroptosis-specific lipid peroxidation,which constituted a“cycle”of *** a result,the metalloimmunotherapy with systemic administration of MMP NDs offered a remarkable tumor inhibition effect for a variety of tumor *** work for the first time discovered the ability of anionic metal ions to activate the immune system and rationally designed bimetallic oxide nanostructures as a multifunctional therapeutic nanoplatform for tumor immunotherapy.

关键词： Metalloimmunotherapy Manganese molybdate nanoparticles cGAS-STING pathway DCs maturation Ferroptosis

On the dynamics and control of the Sun-Earth L_(2) tetrahedral formation

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Astrodynamics 2021年第4期5卷 331-346页

作者： Yijun Lian Zhuoxi Huo Yu cheng College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China School of Automation Beijing University of Posts and TelecommunicationsBeijing 100876China

The dynamics and control of a tetrahedral spacecraft formation flying in the Sun-Earth L2 region is initiatively studied,based on the circular restricted three-body problem(CR3BP).Driven by the science goal of identifying extra-solar terrestrial planets and the requirement of imaging optics,a conceptional four-spacecraft triangular pyramid configuration has been proposed for the Multiple-spacecraft Exoplanet Aperture sYnthetic INterferometer(MEAYIN)project,China’s first mid-infrared interferometric imaging *** it looked promising from an optical perspective,the configuration has not been verified *** formation is required to be virtually“rigid”,because its mutual distances and inertial pointing direction must be maintained with very high accuracy during each *** this study,the spatial geometrical relationship between the four spacecraft was established by introducing the parameters of lengths,angles,and a reference *** first contribution is that a compact set of normalized factors and critical time indices are defined,which can provide a complete description of the drift of the shape and pointing direction of the configuration,caused by the unstable dynamical *** design variables are isolated and analyzed,and their individual impacts on the uncontrolled evolution of the formation are *** main results obtained reveal that the dimensions of the rigid configuration allow a free drift for a time period on the order of tens of hours,while the inertial pointing direction will be lost within merely tens of ***,to form a rigid configuration,the control challenge lies in the fact that control efforts are frequently required for each spacecraft in the fleet,owing to the diverging *** a second contribution,a simple and feasible control algorithm is proposed to maintain the rigidity of the formation *** results indicate that the associated energy cost is merely 0.05 m/s per obser

关键词： tetrahedron configuration Multiple-spacecraft Exoplanet Aperture sYnthetic INterferometer(MEAYIN) formation flying dynamics and control interferometry libration point orbit

On Conformally Flat(α,β)-metrics with Special Curvature Properties

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Acta Mathematica Sinica,English Series 2015年第5期31卷 879-892页

作者： Min Gao YUAN Xin Yue cheng Department of Mathematical Sciences Indiana University Purdue University Indianapolis School of Mathematics and Statistics Chongqing University of Technology

In this paper, we study a significant non-Riemannian quantity E-curvature, which is defined by S-curvature. Firstly, we obtain the formula of E-curvature for （α,β）-metrics. Based on it, we show that the E-curvature vanishes for a class of （α,β）-metrics. In the end, we get the relation of E-curvature for conformally related Finsler metrics, and classify conformally flat （α,β）-metries with almost vanishing E-curvature.

关键词： (α,β)-metrics conformaliy fiat curvature

A Game-Theoretic Approach to Elastic Control in Software-Defined Networking

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China Communications 2016年第5期13卷 103-109页

作者： Hongchang Chen Guozhen cheng Zhiming Wang National Digital Switching System Engineering&Technological R&D Center Zhengzhou 450002China

Elastic control could balance the distributed control plane in Software-Defined Networking(SDN). Dynamic switch migration has been proposed to achieve it. However, existing schemes mainly focus on how to execute migration operation, but not why. This paper designs a decision-making mechanism based on zero-sum game theory to reelect a new controller as the master for migrated switches. It first chooses a switch for migration in the heavy controller which invites its neighbors as the game players to compete for the master role of this switch in the game-playing field(GPF) which is an occasional and loose domain for game-playing. Second, based on the concept of GPF, we design a decentralized strategy to play the game and determine which player as the final master. We implement it by extending the Open Flow protocol. Finally, numerical results demonstrate that our distributed strategy can approach elastic control plane with better performance.

关键词： software-defined networking master election game theory OpenFlow

Model Updating for High Speed Aircraft in Thermal Environment Using Adaptive Weighted-Sum Methods

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第3期33卷 362-369页

作者： He Huan He cheng Chen Guoping The State Key Lab of Mechanics and Control for Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 P.R. China Research Institute of Pilotless Aircraft Nanjing University of Aeronautics and Astronautics Nanjing 210016 P.R. China

Model updating for aircraft in a high temperature environment(HTE)is proposed based on the hierarchical *** this method,the problem can be decomposed into temperature field updating and dynamic structural *** order to improve the estimation accuracy,the model updating problem is turned into a multi-objective optimization problem by constructing the objective function which combined with residues of modal frequency and effective modal *** the metamodeling,support vector regression(SVR)is introduced to improve the optimization efficiency,and the solution can be determined by adaptive weighted-sum method(AWS).Finally,the proposed method is tested on a finite element(FE)model of a reentry vehicle *** results show that the multi-objective model updating method in HTE can identify the input parameters of the temperature field and structure with good accuracy.

关键词： hierarchical high temperature environment(HTE) support vector regression(SVR) multi-objective optimization model updating