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Numerical simulation of pulsatile non-Newtonian flow in the carotid artery bifurcation

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Acta Mechanica Sinica 2009年第2期25卷 249-255页

作者： Yubo Fan Wentao Jiang Yuanwen Zou Jinchuan Li Junkai Chen xiaoyan deng School of Biological Science and Medical Engineering Beihang University 100191 Beijing China Biomechanical Engineering Laboratory Sichuan University610065 Chengdu China

Both clinical and post mortem studies indicate that, in humans, the carotid sinus of the carotid artery bifurcation is one of the favored sites for the genesis and development of atherosclerotic lesions. Hemodynamic factors have been suggested to be important in atherogenesis. To understand the correlation between atherogenesis and fluid dynamics in the carotid sinus, the blood flow in artery was simulated numerically. In those studies, the property of blood was treated as an incompressible, Newtonian fluid. In fact, however, the blood is a complicated non-Newtonian fluid with shear thinning and viscoelastic properties, especially when the shear rate is low. A variety of non-Newtonian models have been applied in the numerical studies. Among them, the Casson equation was widely used. However, the Casson equation agrees well only when the shear rate is less than 10 s-1. The flow field of the carotid bifurcation usually covers a wide range of shear rate. We therefore believe that it may not be sufficient to describe the property of blood only using the Casson equation in the whole flow field of the carotid bifurcation. In the present study, three different blood constitutive models, namely, the Newtonian, the Casson and the hybrid fluid constitutive models were used in the flow simulation of the human carotid bifurcation. The results were compared among the three models. The results showed that the Newtonian model and the hybrid model had verysimilar distributions of the axial velocity, secondary flow and wall shear stress, but the Casson model resulted in significant differences in these distributions from the other two models. This study suggests that it is not appropriate to only use the Casson equation to simulate the whole flow field of the carotid bifurcation, and on the other hand, Newtonian fluid is a good approximation to blood for flow simulations in the carotid artery bifurcation.

关键词： Casson equation Hybrid fluid Newtonianfluid Carotid artery bifurcation

Optimization of Sample Pretreatment for Determination of Polycyclic Aromatic Hydrocarbons in Estuarine Sediments by Gas Chromatography

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Journal of Ocean University of China 2012年第2期11卷 159-164页

作者： WANG Yan LI Xianguo PENG Xuewei TANG Xuli deng xiaoyan Key Laboratory of Marine Chemical Theory and Technology Ministry of EducationOcean University of ChinaQingdao 266100P.R.China

This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.

关键词： ultrasonic extraction thin layer chromatography estuarine sediment PAHs

Gender differences in cardiovascular disease

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Medicine in Novel Technology and Devices 2019年第4期4卷 1-6页

作者： Zujie Gao Zengsheng Chen Anqiang Sun xiaoyan deng School of Biological Science and Medical Engineering Key Laboratory for Biomechanics and Mechanobiology of Ministry of EducationBeihang UniversityBeijing100083China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing100083China

Cardiovascular disease(CVD)is one of the leading causes of death *** the incidence of CVD in women is usually lower than in men,women have a higher mortality and worse prognosis after acute cardiovascular *** gender differences exist in various CVDs,including coronary heart disease,stroke,heart failure and aortic *** gender differences have caused widespread concerns and the consideration of gender differences is of great importance for the prevention,diagnosis,treatment and management of *** review aims to provide an overview of gender-related differences in several typical CVDs and to list and to analyze the possible causes associated with the differences,in order to highlight the necessity of taking into account gender differences in determination of the cardiovascular risk *** research can focus on how to define and add gender-related indicators to current risk assessment and management strategies.

关键词： Gender differences Cardiovascular disease Coronary heart disease Stroke

Adsorption performance and physicochemical mechanism of MnO_(2)-polyethylenimine-tannic acid composites for the removal of Cu(Ⅱ) and Cr(Ⅵ) from aqueous solution

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Frontiers of Chemical Science and Engineering 2021年第3期15卷 538-551页

作者： xiaoyan deng Luxing Wang Qihui Xiu Ying Wang Hong Han Dongmei Dai Yongji Xu Hongtao Gao Xien Liu College of Environment and Safety Engineering State Key Laboratory Base of Eco-Chemical EngineeringQingdao University of Science&TechnologyQingdao 266042China College of Chemistry and Molecular Engineering State Key Laboratory Base of Eco-Chemical EngineeringQingdao University of Science&TechnologyQingdao 266042China

In this work,an adsorbent,which we call MnPT,was prepared by combining MnO_(2),polyethylenimine and tannic acid,and exhibited efficient performance for Cu(Ⅱ) and Cr(VI) removal from aqueous *** oxygen/nitrogen-containing functional groups on the surface of MnPT might increase the enrichment of metal ions by *** maximum adsorption capacities of MnPT for Cu(Ⅱ) and Cr(Ⅵ) were 121.5 and 790.2 mg·g^(-1),*** surface complexation formation model was used to elucidate the physicochemical interplay in the process of Cu(Ⅱ) and Cr(Ⅵ) co-adsorption on *** force,solvation action,adsorbate-adsorbate lateral interaction,and complexation were involved in the spontaneous adsorption *** electrostatic action was dominant in the initial stage,whereas chemical action was the driving force leading to adsorption *** should be noted that after adsorption on the surface of MnPT,Cr(Ⅵ) reacted with some reducing functional groups(hydroxylamine-NH_(2))and was converted into Cr(Ⅲ).The adsorption capacity declined by 12% after recycling five *** the adsorption mechanism might provide a technical basis for the procedural design of heavy metal *** MnPT nanocomposite has been proven to be a low-cost,efficient,and promising adsorbent for removing heavy metal ions from wastewater.

关键词： MnO_(2)-polyethylenimine-tannic acid composite surface complexation formation model Cu(Ⅱ) Cr(Ⅵ) physicochemical mechanism

Microfluidic chips for the endothelial biomechanics and mechanobiology of the vascular system

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BIOCELL 2021年第4期45卷 797-811页

作者： HAORAN SU KEXIN LI XIAO LIU JING DU LI WANG xiaoyan deng YUBO FAN Beijing Advanced Innovation Centre for Biomedical Engineering Key Laboratory for Biomechanics and Mechanobiology of Chinese Education MinistrySchool of Biological Science and Medical EngineeringBeihang UniversityBeijingChina100083 School of Engineering Medicine Beihang UniversityBeijingChina100083 Artificial Intelligence Key Laboratory of Sichuan Province School of Automation and Information EngineeringSichuan University of Science and EngineeringZigongChina643000 Beijing Research Center of Urban System Engineering BeijingChina

Endothelial cells arranged on the vessel lumen are constantly stimulated by blood flow,blood pressure and pressureinduced cyclic *** stimuli are sensed through mechanical sensory structures and converted into a series of functional responses through mechanotransduction *** process will eventually affect vascular ***,there has been an urgent need to establish in vitro endothelial biomechanics and mechanobiology of models,which reproduce three-dimensional structure vascular *** recent years,the rapid development in microfluidic technology makes it possible to replicate the key structural and functionally biomechanical characteristics of ***,we summarized the progress of microfluidic chips used for the investigation of endothelial biomechanics and mechanobiology of the vascular ***,we elucidated the contribution of shear stress and circumferential stress,to vascular ***,we reviewed some applications using microfluidic technology in angiogenesis and vasculogenesis,endothelial permeability and mechanotransduction,as well as the blood-brain barrier under these physical ***,we discussed the future obstacles in terms of the development and application of microfluidic vascular chips.

关键词： Endothelial cells Vascular system Mechanotransduction Microfluidic chip

The role of hemoglobin in nitric oxide transport in vascular system

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Medicine in Novel Technology and Devices 2020年第1期5卷 1-6页

作者： Haoran Su Xiao Liu Jing Du xiaoyan deng Yubo Fan Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education Institute of Nanotechnology for Single Cell AnalysisBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China

Nitric oxide(NO)plays a pivotal role in vascular homeostasis and its functions practice in a dose-dependent manner in which too high and too low NO concentration may both induce the development of cardiovascular diseases,which indicates the balance between NO formation and scavenging is *** presented over the last two decades has indicated hemoglobin(Hb)can affect NO dynamic *** role of Hb was once thought to play in NO signaling as inhibiting NO transport,but now several mechanisms have found that Hb may preserve and even regulate NO *** the tremendous amount of work devoted to this field,major questions concerning precise mechanisms of NO activity preservation as well as if and how Hb creates NO activity remain *** this review,we discuss the role of hemoglobin in NO formation,transport and *** also discuss how these mechanisms of the imbalance between NO and hemoglobin induce related diseases,which may serve as the basis for novel therapeutics.

关键词： Hemoglobin Nitric oxide Transport Balance Diseases

Interaction of arterial proteoglycans with low density lipoproteins(LDLs):From theory to promising therapeutic approaches

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Medicine in Novel Technology and Devices 2019年第3期3卷 1-8页

作者： Hongyan Kang Jinyan Lu Jiali Yang Yubo Fan xiaoyan deng Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China Beijing Advanced Innovation Centre for Biomedical Engineering Beihang UniversityBeijing100083China

Although atherosclerosis is a multifactorial process,proteoglycans mediated lipoprotein(LDL)retention at the subendothelial space is a necessary and sufficient event in provoking lesion ***(PGs)are usually composed of one core protein backbone with one or more glycosaminoglycan chains(GAGs)covalently linked,mainly include perlecan,biglycan,versican,and *** interaction between LDL and proteoglycans is apparently mediated by the basic amino acids in apoB-100,the moiety of LDL,electrostatic interacting with the negatively charged GAGs(sulfate or carbohydrate groups)of proteoglycans or though some bridge molecules like sphingomyelinase(SMase)or lipoprotein lipase(LpL).In the later section,we collate the promising therapeutic approaches that have been proposed up to now,targeting LDL-PGs *** should be concluded that previous studies on interaction between LDL and PGs mainly focused on perlecan,biglycan,decorin,and versican that all located in the extracellular matrix(ECM),future studies should pay more attention to the endothelial surface glycocalyx and its interaction with LDLs,seeking promising therapeutic targets more specifically.

关键词： Proteoglycans Low-density lipoprotein Atherosclerosis Endothelial glycocalyx

A proposed design of flow diverter and it’s hemodynamic validation

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Medicine in Novel Technology and Devices 2021年第1期9卷 37-44页

作者： Anqiang Sun Chengcheng Zhao Zujie Gao xiaoyan deng Hancheng Qiu School of Biological Science and Medical Engineering Beijing Advanced Innovation Centre for Biomedical EngineeringKey Laboratory for Biomechanics and Mechanobiology of Ministry of EducationBeihang UniversityBeijing100083China State Key Laboratory of Tribology Tsinghua UniversityBeijing100084China Department of Neurosurgery Beijing Tiantan HospitalCapital Medical UniversityBeijing100070China

Flow diverter intervention is a cutting-edge treatment for intracranial aneurysms by altering the flow field and reducing the pressure in the aneurysm ***,the rupture rate and complications rate are still *** this study,a new design of flow diverter based on Bernoulli’s equation was proposed and hemodynamics evaluation of it was *** numerical model of a patient specific internal carotid aneurysm was established based on computed tomography scan images(Model C).The aneurysm models with normal diverter(ND)and local stenosed diverter(LSD)were modified from the patient-specific *** blood flow characteristics were obtained and analyzed by numerical simulation while the in vitro experiments were conducted using three-dimensional printed silicone models and pressure measurement *** both ND and LSD models,the blood flow into the aneurysm have been significantly blocked by the diverters and the pressure in the aneurysm sac have been *** pressure drop and the wall shear stress on the aneurysm wall in the LSD model are higher than that in the ND *** oscillatory shear index and relative residence time in the aneurysm wall of LSD are lower than that in the ND *** pressure measurement in the vitro experiment also qualitatively verified the results of pressure comparison in the numerical *** conclusion,the simulation results and in vitro experiments verified that diverter can certainly reduce the pressure in the aneurysm,and the newly design diverter with local stenosis can strengthening this effect.

关键词： Intracranial aneurysm Diverter Hemodynamics Local stenosed diverter Pressure

Non-physiological shear stress-induced blood damage in ventricular assist device

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Medicine in Novel Technology and Devices 2019年第3期3卷 9-15页

作者： Zengsheng Chen Anqiang Sun Hongyu Wang Yubo Fan xiaoyan deng Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing100083China School of Biological Science and Medical Engineering Beihang UniversityBeijing100083China

Ventricular assist devices(VADs)have been used for treating the end-stage heart failure(HF)patients in the past few decades,which had improved survival *** parallel,clinical applications of VADs are accompanied with endangered complications,such as thrombosis,bleeding and infection,which hamper the patient *** shear stress(NPSS)is inevitably created during VAD *** HF patients implanted with VADs,this high level NPSS can induce damage on blood components including blood cells(red blood cells,platelets,leukocytes et al.)and protein(von Willebrand Factor(VWF)).The damage of these blood cells and proteins may lead to the dysfunction of coagulation and immune systems,contributing to complications in VAD *** understand how VADs-created NPSS induces blood damage,and find the link between NPSS-induced blood damage and VAD related complications would potentially help to guide the VAD optimization and to find the effect way for treating VAD associated *** we provide a review to investigate what is currently known about NPSS-induced blood damage within VADs and how the NPSS-induced blood damage links to complications(thrombosis,bleeding and infection)in VAD patients.

关键词： Ventricular assist device Non-physiological shear stress Blood damage Thrombosis Bleeding