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Multiple positive periodic solutions for a generalized delayed population model with an exploited term

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Science China Mathematics 2007年第1期50卷 27-34页

作者： zheng-qiu zhang Zhi-cheng WANG College of Mathematics and Econometrics Hunan UniversityChangsha 410082China

In this paper, the existence of two positive periodic solutions for a generalized delayed population model with an exploited term is established by using the continuation theorem of the coincidence degree theory.

关键词： two positive periodic solutions generalized delayed population model continuation theorem of coincidence degree theory exploited term 34K13

An integrated environmental improvement of marshlands:impact on control and elimination of schistosomiasis in marshland regions along the Yangtze River,China

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Infectious Diseases of Poverty 2017年第1期6卷 624-633页

作者： Le-Ping Sun Wei Wang Yin-Ping Zuo zheng-qiu zhang Qing-Biao Hong Guo-Jing Yang Hong-Ru Zhu You-Sheng Liang Hai-Tao Yang Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention No.117 YangxiangMeiyuanWuxi CityJiangsu Province 214064China Jiangsu Provincial Key Laboratory on Parasites and Vector Control Technology No.117 YangxiangMeiyuanWuxi CityJiangsu Province 214064China Jiangsu Institute of Parasitic Diseases No.117 YangxiangMeiyuanWuxi CityJiangsu Province 214064China Yangzhou Municipal Center for Disease Control and Prevention No.36 Yanfu East RoadYangzhou CityJiangsu Province 225000China Yizheng County Center for Disease Control and Prevention NO.1 Jiankang RoadYangzhou CityJiangsu Province 211440China

Background:Schistosomiasis is a global snail-transmitted infectious disease of *** control had been achieved in China in 2015 after the control efforts for over 60 ***,the remaining core regions endemic for Schistosoma japonicum are mainly located in the marshland and lake regions along the Yangtze River ***:During the period from 2001 through 2015,an integrated environmental improvement of the marshlands was carried out through the implementation of industrial,agricultural and resources development projects in Yizheng County along the Yangtze *** infection in humans,livestock and snails was estimated by serology,stool examination,hatching technique and microscopy during the 15-year study period to evaluate the effect of the integrated environmental improvement on control and elimination of ***:A 0.05%overall rate of *** infection was observed in snails during the 15-year study period,and no infected snails were detected since *** overall prevalence of *** infection was 0.09%in humans during the study period,and no human infection was found since *** addition,only 13 bovines were identified with *** infection in 2003 during the 15-year study period,and since 2004,no infection was found in ***:The results of the present study demonstrate that the implementation of industrial,agricultural and water resources development projects,not only alters snail habitats in marshland regions,and promotes local economic development,which appears a win-to-win strategy to block the transmission of *** and accelerate socio-economic development along the Yangtze River.

关键词： Schistosomiasis Oncomelania hupensis Environmental improvement Marshland regions Yangtze River basin China

Microstructure and mechanical properties of dissimilar Al-Cu joints by friction stir welding

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Transactions of Nonferrous Metals Society of China 2015年第6期25卷 1779-1786页

作者：张秋征宫文彪刘威长春工业大学先进结构材料教育部重点实验室长春130012

Dissimilar friction stir welding between 1060 aluminum alloy and annealed pure copper sheet with a thickness of 3 mm was investigated. Sound weld was obtained at a rotational speed of 1050 r/min and a welding speed of 30 mm/min. Intercalation structure formed at the crown and Cu/weld nugget （WN） area promotes interracial diffusion and metallurgical bonding of aluminum and copper. However, corrosion morphology reveals the weak bonding mechanism of internal interface, which causes the joint failing across the interface with a brittle-ductile mixed fracture mode. The tensile strength of the joint is 148 MPa, which is higher than that of the aluminum matrix. Crystal defects and grain refinement by severely plastic deformation during friction stir welding facilitate short circuit diffusion and thus accelerate the formation of A14Cu9 and A12Cu intermetallic compounds （IMCs）. XRD results show that A14Cu9 is mainly in Cu/WN transition zone. The high dislocation density and formation of dislocation loops are the major reasons of hardness increase in the WN.

关键词： aluminum alloy copper friction stir welding dissimilar material microstructure mechanical properties

基于拉曼光谱技术的枇杷果实β-胡萝卜素含量无损测定研究

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光谱学与光谱分析 2016年第11期36卷 3572-3577页

作者：王涛裘正军张卫正赵艳茹何勇浙江大学生物系统工程与食品科学学院浙江杭州310058

β-胡萝卜素作为一种重要的营养元素,其在果蔬活体内的测定方法通常必须对样品进行破坏,并且耗时、费力。采用拉曼光谱技术预测活体枇杷果实内β-胡萝卜素含量,以高效液相色谱法(HPLC)检测值作为参考值,采用高斯平滑对光谱数据进行预处... 详细信息

β-胡萝卜素作为一种重要的营养元素,其在果蔬活体内的测定方法通常必须对样品进行破坏,并且耗时、费力。采用拉曼光谱技术预测活体枇杷果实内β-胡萝卜素含量,以高效液相色谱法(HPLC)检测值作为参考值,采用高斯平滑对光谱数据进行预处理,同时使用多项式拟合(PF)的方法对光谱数据进行背景荧光扣除,以标准β-胡萝卜素的拉曼图谱为基础,选取了三个特征频移,以特征频移和截取的光谱建立了MLR模型、PLSR模型以及LS-SVM模型,取得了比较好的预测精度。其中LS-SVM模型的预测精度最高,其预测相关系数R_p^2达到了0.91,表明通过拉曼光谱对活体枇杷内β-胡萝卜素的含量检测是实际可行的。

关键词： β-胡萝卜素枇杷拉曼光谱 HPLC

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一个具有阶段结构的捕食者食饵系统的周期解

数学学报（中文版） 2005年第3期48卷 541-548页

作者：张正球王志成湖南大学数学与计量经济学院长沙410082

本文研究一类捕食者具有阶段结构的捕食者食饵系统,利用重合度理论建立了这类系统正周期解的存在性结果.

关键词：周期解阶段结构拓扑度理论

Influence of introducing Zr,Ti,Nb and Ce elements on externally solidified crystals and mechanical properties of high-pressure die-casting Al–Si alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 147-153页

作者： Junjie Li Wenbo Yu Zhenyu Sun Weichen zheng Liangwei zhang Yanling Xue Wenning Liu Shoumei Xiong Center of Materials Science and Engineering School of Mechanical and Electronic Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Traffic&Transportation Engineering Central South UniversityChangsha 410075China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile *** can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated ***,the development of non-heat treatment Al alloys is becoming the hot *** addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of *** achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and *** influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic *** results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased ***,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical *** introduction of Ce resulted in the poisoning effect and reduced mechanical properties.

关键词： aluminium alloy high-pressure die-casting externally solidified crystals non-heat treatment

Exercise preconditioning alleviates ischemia-induced memory deficits by increasing circulating adiponectin

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Neural Regeneration Research 2025年第5期20卷 1445-1454页

作者： Meifeng zheng Borui zhang Sonata S Y Yau Kwok-Fai So Li zhang Haining Ou Department of Rehabilitation Medicine Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina Department of Rehabilitation Medicine The Fifth Clinical College of Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina Key Laboratory of CNS Regeneration(Ministry of Education) Guangdong-Hong Kong-Macao Institute of CNS RegenerationJinan UniversityGuangzhouGuangdong ProvinceChina Department of Rehabilitation Sciences The Hong Kong Polytechnic UniversityHong Kong Special Administrative RegionChina State Key Laboratory of Brain and Cognitive Science Li Ka Shing Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina Center for Exercise and Brain Science School of PsychologyShanghai University of SportShanghaiChina Neuroscience and Neurorehabilitation Institute University of Health and Rehabilitation SciencesQingdaoShandong ProvinceChina

Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug *** exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after *** this study,we determined whether exercise training before disease onset can alleviate the severity of cerebral *** also examined the role of exercise-induced circulating factors in these *** mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery *** found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory *** analysis showed that circulating adiponectin plays a critical role in these preventive effects of *** activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise *** summary,our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise.

关键词： adiponectin cerebral ischemia exercise pre-conditioning hippocampus memory function middle cerebral artery occlusion prefrontal cortex synaptic proteins treadmill exercise

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World Journal of Clinical Cases 2025年第6期13卷 24-29页

作者： Wen-Jin Yuan Yi-Juan zheng Bing-Rong zhang Yi-Jie Lin You Li Yan-Yan qiu Xue-Ping Yu Department of Infection Disease Clinical Medical Research Center for Bacterial and Fungal Infectious Diseases of Fujian provinceFujian Medical University Affiliated First Quanzhou HospitalQuanzhou 362000Fujian ProvinceChina

BACKGROUND Hydroxyurea,an antimetabolite,is frequently prescribed for various hemato-logical disorders,and its common side effects include gastrointestinal problems,cutaneous or mucosal lesions and pyrexia/*** SUMMARY This study reports the case of a 67-year-old woman who developed recurrent abdominal pain after 10 years of continuous hydroxyurea therapy for primary *** revealed an ileocecal *** discontinuing hydroxyurea therapy for 6 months,follow-up colonoscopy showed a significant reduction in the *** We consider cecal ulcers as a rare complication of hydroxyurea therapy which typically resolves upon stopping the drug.

关键词： Hydroxyurea Ulcer Abdominal pain Thrombocythemia Colonoscopy Case report

Small extracellular vesicles derived from cerebral endothelial cells with elevated microRNA 27a promote ischemic stroke recovery

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Neural Regeneration Research 2025年第1期20卷 224-233页

作者： Yi zhang Zhongwu Liu Michael Chopp Michael Millman Yanfeng Li Pasquale Cepparulo Amy Kemper Chao Li Li zhang zheng Gang zhang Department of Neurology Henry Ford HospitalDetroitMIUSA Department of Physics Oakland UniversityRochesterMIUSA Department of Pathology Henry Ford HospitalDetroitMIUSA Division of Pharmacology Department of NeuroscienceReproductive and Dentistry SciencesSchool of MedicineUniversity of Naples“Federico Ⅱ”NaplesItaly

Axonal remodeling is a critical aspect of ischemic brain repair processes and contributes to spontaneous functional *** previous in vitro study demonstrated that exosomes/small extracellular vesicles(sEVs)isolated from cerebral endothelial cells(CEC-sEVs)of ischemic brain promote axonal growth of embryonic cortical neurons and that microRNA 27a(miR-27a)is an elevated miRNA in ischemic *** the present study,we investigated whether normal CEC-sEVs engineered to enrich their levels of miR-27a(27a-sEVs)further enhance axonal growth and improve neurological outcomes after ischemic stroke when compared with treatment with non-engineered CEC-sEVs.27a-sEVs were isolated from the conditioned medium of healthy mouse CECs transfected with a lentiviral miR-27a expression *** EVs isolated from CECs transfected with a scramble vector(Scra-sEVs)were used as a *** male mice were subjected to permanent middle cerebral artery occlusion and then were randomly treated with 27a-sEVs or *** array of behavior assays was used to measure neurological *** with treatment of ischemic stroke with Scra-sEVs,treatment with 27a-sEVs significantly augmented axons and spines in the peri-infarct zone and in the corticospinal tract of the spinal grey matter of the denervated side,and significantly improved neurological *** vitro studies demonstrated that CEC-sEVs carrying reduced miR-27a abolished 27a-sEV-augmented axonal *** analysis revealed that 27a-sEVs systemically administered preferentially localized to the pre-synaptic active zone,while quantitative reverse transcription-polymerase chain reaction and Western Blot analysis showed elevated miR-27a,and reduced axonal inhibitory proteins Semaphorin 6A and Ras Homolog Family Member A in the peri-infarct *** of the Clathrin-dependent endocytosis pathway substantially reduced neuronal internalization of *** data provide evidence that 27a-sEVs have

关键词： axonal remodeling cerebral endothelial cells exosomes miR-27a mitochondria Semaphorin 6A small extracellular vesicles stroke