The micropolar fluid model for blood flow through a tapered artery with a stenosis

A micropolar model for axisymmetric blood flow through an axially nonsymmetreic but radially symmetric mild stenosis tapered artery is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the axial shape of the stenosis can be changed easily just by varying a parameter （referred to as the shape parameter）. The model is also used to study the effect of the taper angle Ф. Flow parameters such as the velocity, the resistance to flow （the resistance impedance）, the wall shear stress distribution in the stenotic region and its magnitude at the maximum height of the stenosis （stenosis throat） have been computed for different values of the shape parameter n, the taper angle Ф, the coupling number N and the micropolar parameter m. It is shown that the resistance to flow decreases with increasing the shape parameter n and the micropolar parameter m while it increases with increasing the coupling number N. So, the magnitude of the resistance impedance is higher for a micropolar fluid than that for a Newtonian fluid model. Finally, the velocity profile, the wall shear stress distribution in the stenotic region and its magnitude at the maximum height of the stenosis are discussed for different values of the parameters involved on the problem.

Effect of warm bladder irrigation fluid for benign prostatic hyperplasia patients on perioperative hypothermia, blood loss and shiver: A meta-analysis

Objective:To find out whether warm bladder irrigation fluid can decrease the occurrence of perioperative hypothermia,blood loss and shiver in patients treated with benign prostatic hyperplasia(BPH).Method:A comprehensive literature review and meta-analysis that included randomized controlled trials(RCTs)related to temperature of irrigation fluid in the perioperative treatment for BPH was taken by researchers.The relevant literature were searched in Chinese database,such as Retrieval Chinese Journal Full-text Database,VIP Journal Database,Wanfang database,as well as in English search engine and database,including Embase,Cochrane and Medline till January 2018.The study quality was assessed by recommended standards from Cochrane Handbook(version 5.1.0).Results:A total of 28 RCTs and 3858 patients were included.The results showed that the incidences of shiver(risk ratio[RR]Z 0.32,95%confidence interval[CI]:0.28e0.36,p<0.001,I^2 Z 0%)and hypothermia(RR Z 0.36,95%CI:0.21e0.59,p<0.001,I^2 Z 67%)in the group of warm irrigation fluid were lower than the group having room-temperature fluid.Room-temperature irrigation fluid group caused a greater drop in body temperature compared to warm irrigation fluid group(p<0.001,I^2 Z 96%).We performed a narrative descriptive statistics only because of substantial heterogeneity.Conclusions:Warm bladder irrigation fluid can decrease the drop of body temperature and the incidence of hypothermia and shiver during and after the operation for BPH.Warm irrigation fluid should be considered as a standard practice in BPH surgeries.

Flow of a biomagnetic viscoelastic fluid:application to estimation of blood flow in arteries during electromagnetic hyperthermia,a therapeutic procedure for cancer treatment

The paper deals with the theoretical investigation of a fundamental problem of biomaguetic fluid flow through a porous medium subject to a magnetic field by using the principles of biomagnetic fluid dynamics （BFD）. The study pertains to a situation where magnetization of the fluid varies with temperature. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a second-grade viscoelastic fluid. The walls of the channel are assumed to be stretchable, where the surface velocity is proportional to the longitudinal distance from the origin of coordinates. The problem is first reduced to solving a system of coupled nonlinear differential equations involving seven parameters. Considering blood as a biomagnetic fluid and using the present analysis, an attempt is made to compute some parameters of the blood flow by developing a suitable numerical method and by devising an appropriate finite difference scheme. The computational results are presented in graphical form, and thereby some theoretical predictions are made with respect to the hemodynamical flow of the blood in a hyperthermal state under the action of a magnetic field. The results clearly indicate that the presence of a magnetic dipole bears the potential so as to affect the characteristics of the blood flow in arteries to a significant extent during the therapeutic procedure of electromagnetic hyperthermia. The study will attract the attention of clinicians, to whom the results would be useful in the treatment of cancer patients by the method of electromagnetic hyperthermia.

Cerebrospinal fluid and blood biomarkers in Alzheimer’s disease

Due to an ever aging society and growing prevalence of Alzheimer’s disease(AD),the challenge to meet social and health care system needs will become increasingly difficult.Unfortunately,a definite ante mortem diagnosis is not possible.Thus,an early diagnosis and identification of AD patients is critical for promising,early pharmacological interventions as well as addressing health care needs.The most advanced and most reliable markers areβ-amyloid,total tau and phosphorylated tau in cerebrospinal fluid(CSF).In blood,no single biomarker has been identified despite an intense search over the last decade.The most promising approaches consist of a combination of several bloodbased markers increasing the reliability,sensitivity and specificity of the AD diagnosis.However,contradictory data make standardized testing methods in longitudinal and multi-center studies extremely difficult.In this review,we summarize a range of the most promising CSF and blood biomarkers for diagnosing AD.

Computational Fluid Dynamics Analysis of Shroud Design on Hemodynamic Performance and Blood Damage in a Centrifugal Blood Pump

Patients with extracorporeal membrane oxygenation still suffer from high rates of complication that linked to the flow field within the blood pump.So it is essential to optimise the geometry of the pump.The specification of shroud design is arguably the necessary design parameter in the centrifugal pump.However,the hemodynamic performances of the different shroud designs have not been studied extensively.In this study,ten different shroud designs were made and divided into two groups as the different covering locations(A:Covering the blade leading edge,B:Covering the blade trailing edge).In every group,six shroud designs with the covering proportions of 0,1/5,2/5,3/5,4/5,1 were made.Detailed computational fluid dynamics(CFD)analyses were performed to investigate their effects on hemodynamics and hydraulic performance at the constant flow condition(4000 rpm,5 L/min).The percentage volumes of the scalar shear stress in specific threshold(τ<1 Pa:Thrombosis,τ>9 Pa:the destruction of von Willebrand factor,τ>50 Pa:Platelet activation,τ>150 Pa:Break of red blood)were used to compare the blood damage of the different shroud designs.Also,the modified index of hemolysis(MIH)were calculated based on a Eulerian approach for different pumps.CFD simulations predicted an increase in the pump head,hydraulic efficiency,a fraction of fluid volume with scalar shear stress values above a threshold(9 Pa,50 Pa,150 Pa)and MIH with increasing shroud covering proportions from 0 to 1 in the same covering location.Also,these above results were higher in group B than group A.This means that the risks of the hemolysis,thrombosis and bleeding increased as the rise of the covering proportion and they were higher in the pump whose shroud covers the blade trailing edge.

A Novel Blood Coagulation Measuring Method Based on the Viscoelasticity of Non-Newtonian Fluid

There are complex and perfect coagulation, anticoagulation and fibrinolysis systems in the human body and their fine regulatory mechanisms. Once the coagulation system and its regulatory mechanisms are destroyed, bleeding or thrombosis will occur very soon. In the blood coagulation, the blood viscoelasticity changes. Therefore, the thrombus elasticity measurement technology can be used to continuously monitor the changing blood viscoelasticity in order to study the process of coagulation. The results of the interaction among the various components of the blood can be obtained from coagulation to fibrinolysis by bedside detection. The traditional electromagnetic induction sensors, based on conventional coil inductance, are manufactured complexly, high cost and non-linear. Therefore, this paper proposes a non-Newtonian fluid viscoelasticity measurement method based on the piezoelectric effect. We use the piezoelectric bimorphs with the diameter of 21 mm and the total thickness of 0.38 mm and DSM coupling probes with the length of 3 mm, 5 mm and 7 mm to design the piezoelectric bimorphs driver. The viscoelasticity of different non-Newtonian fluids is tested. The vibration amplitudes of the piezoelectric bimorphs and liquid surfaces range from 0.43 μm to 3.52 μm. Consequently, the feasibility of in vitro detection of thrombus is confirmed in principle and the above scheme is validated theoretically and experimentally, which provides the basis for the measurement of blood viscoelasticity, the in vitro detection of thrombus and the manufacture of blood coagulation instrument.

Novel Method Employing Accelerated-Oscillated Wave Saline Solutions to Unblock Blood Vessels—Physics and Fluid Dynamics Perspectives and Simulations

This research assesses the speed of blood flow across blood vessels and more specifically the veins in terms of Reynold’s number (laminar flow vs. turbulence flow) and in terms of overall speed of the blood when being injected with high-speed saline particles. The authors propose a novel technique to generate accelerated-waved particles built from saline solution to enable the unblocking of partially-blocked healthy-walled veins, and to restore normal operations of these veins. The novel technique encompasses a pump that accelerates saline solutions into the blood stream of the vein and these oscillated waves break down the fats or deposits inside the veins in order to help the blood to flow freely without any obstruction. This research simulated the vein with blood stream using characteristics of the vein in terms of vein diameter, blood density, venous blood flow, and the viscosity of the blood at the normal body temperature. The speed of the overall blood flow after the injection of the accelerated saline droplet solution was determined as well as the depth of penetration of the accelerated particles in order to cleanse the inside of the vein. Results are promising in terms of not altering significantly the overall speed of the bloodstream and also in terms of efficacy of the length of the vein which is being cleaned using this accelerated particle method.

Simulation of Variable Viscosity and Jeffrey Fluid Model for Blood Flow Through a Tapered Artery with a Stenosis

Non-Newtonian fluid model for blood flow through a tapered artery with a stenosis and variable viscosity by modeling blood as Jeffrey fluid has been studied in this paper.The Jeffrey fluid has two parameters,the relaxation time λ1 and retardation time λ2.The governing equations are simplified using the case of mild stenosis.Perturbation method is used to solve the resulting equations.The effects of non-Newtonian nature of blood on velocity profile,temperature profile,wall shear stress,shearing stress at the stenotsis throat and impedance of the artery are discussed.The results for Newtonian fluid are obtained as special case from this model.

Acrylamide exposure impairs blood-cerebrospinal fluid barrier function

Previous studies show that chronic acrylamide exposure leads to central and peripheral neu- ropathy. However, the underlying mechanisms remained unclear. In this study, we examined the permeability of the blood-cerebrospinal fluid barrier, and its ability to secrete transthyretin and transport leptin of rats exposed to acrylamide for 7, 14, 21 or 28 days. Transthyretin levels in cerebrospinal fluid began to decline on day 7 after acrylamide exposure. The sodium fluorescein level in cerebrospinal fluid was increased on day 14 after exposure. Evans blue concentration in cerebrospinal fluid was increased and the cerebrospinal fluid/serum leptin ratio was decreased on days 21 and 28 after exposure. In comparison, the cerebrospinal fluid/serum albumin ratio was increased on day 28 after exposure. Our findings show that acrylamide exposure damages the blood-cerebrospinal fluid barrier and impairs secretory and transport functions. These changes may underlie acrylamide-induced neurotoxicity.

THERAPEUTIC EFFECTS OF EAR ACUPUNCTURE IN 52 CASES WITH REACTION TO BLOOD TRANSFUSION OR FLUID INFUSION

The author used ear acupuncture to treat 52 cases with reaction to blood transfu-sion or fluid infusion and obtained a good and quick therapeutic effect, 50 cases (96. 2％) were curedand 2 cases (3. 8％) improved.

Relationship between leptin levels in maternal blood,amniotic fluid,arterial and venous cord blood and fetal growth

Objective:To study the relationship between leptin concentration and fetal growth.Methods: Levels of leptin in maternal serum, amniotic fluid, arterial and venouscord blood of 65 normal parturients (gestational age 37-42weeks) were measured by ra-dioimmunoassay (RIA) method. At the same time, maternal blood lipids were detected.Neonates were divided into three groups: small for gestational age (SGA) group (n=10), appropriate for gestational age (AGA) group (n=45), large for gestational age(LGA) group (n= 10). Statistical analysis was performed by t test, variance analysisand correlation analysis.Results: (1) There was no obvious correlation between leptin concentrations in ma-ternal serum and arterial/ venous cord blood, amniotic fluid, and also no correlationwith birth weight and placental weight (P＞0.05). Maternal body mass index signifi-cantly correlated with birth weight and neonatal length and leptin levels in arterial andvenous cord blood (P＜0.01). Leptin levels in arterial and venous cord blood positivelycorrelated significantly with placental and neonatal weight and body length (P＜0.01)and negatively correlated with high density lipoprotein (P＜0. 01). There was no obvi-ous correlation between fetal gender and leptin concentrations in maternal serum, arteri-al and venous cord blood and amniotic fluid; (2) Leptin levels in arterial and venouscord blood , placental weight in LGA group were significantly higher than those in SGAand AGA group (P＜0.05). Among three groups, leptin concentrations in maternalblood were significantly higher than those in arterial and venous cord blood (P＜0.05).Conclusions: (1)Fetal leptin is synthesized in uterus, born of itself and placenta.Leptin levels in arterial and venous cord blood are related to the intrauterine growthpattern. It might positively regulate birth weight and body fat content. (2)Either mater-nal or fetal leptin was not correlated with fetal gender. There is no gender difference infetal leptin concentrations.

Cerebrospinal fluid and blood biomarkers in the diagnostic assays of Alzheimer's disease

The anti-amyloid-j(anti-Aβ)fibrils and soluble oligomers antibody aducanumab were approved to effectively slow down the progression of A lzheimer's disease(AD)at higher doses in 2019,reaffirming the therapeutic effects of targeting the core pathology of AD.A timely and accurate diagnosis in the prodromal or pre-dementia stage of AD is essential for patient recruitment,stratifcation,and monitoring of treat ment effects.A D core biomarkers amyloid-B(Aβ1-42),total tau(t-tau),and phosphorylated tau(p-tau)have been clinically validated to reflect AD-type pathological changes through cerebrospinal fuid(CSF)measurement or positron-emission to-mography(PET)and found to have high diagnostic performance for AD identification in the stage of mild cognitive impairment.The development of ultrasensitive immunoassay technology enables AD pathological proteins such as tau and neurofilament light(NFL)to be measured in blood samples.However,combined biomarker detection or targeting multiple biomarkers in immunoassays will increase detection sensitivity and specifcity and improve diagnostic accuracy..This review summarizes and analyzes the performance of current detection methods for early diagnosis of AD,and provides a concept of detection method based on multiple biomarkers instead of a single target,which may become a potential tool for early diagnosis of AD in the future.

Occupational exposures to blood and body fluids (BBF): Assessment of knowledge, attitude and practice among health care workers in general hospitals in Lebanon

Healthcare workers (HCWs) who are employed in traditional health care workplaces face a serious danger that may threaten their life;it is their exposure to blood and body fluids (BBF). In Lebanon, the introduction of a hospital accreditation system has put a particular emphasis on staff safety, and on the evaluation of professional practice (EPP) programs. Methods: A cross-sectional survey was conducted amongst 277 HCWs working in 4 general hospitals in South Lebanon. Objective: 1) describe the prevalence and the risk factors for occupational exposure to BBF among HCWs;2) evaluate knowledge, attitude, and practices of HCW concerning blood-borne pathogens and adherence to universal safety precautions. Results: The mean age of the respondents was 32.14 years (SD = 10.33), 57.4% were females. 43.3% of HCWs expressed that they use gloves all the time for every activeity of care. 67.1% were aware that needles should not be recapped after use;registered nurses and nursing students were more aware than physicians and nursing assistants (nurse) in this subject. 30% of HCWs declared having had at least one occupational exposure to BBF;62.7% of all accidental exposure was reported to the department responsible for managing exposures. Percutaneous injuries were the most frequently reported. Vaccination coverage was 88.4% for hepatitis B, and 48.4% against influenza. The source patient was tested in 43.4% of reported BBF exposures. Accidental exposure to BBF was more frequent in older people (OR = 3.42;p = 0.03) and the more experienced. Subjects working in intensive care unit ward reported more exposure to BBF (OR = 3;p = 0.04). Participants incurring exposure to BBF resorted to different measures after the injury suggesting a lack of a uniform policy for post-exposure prophylaxis. Conclusion: Exposure to BBF represents an important and frequently preventable occupational hazard for HCWs in Lebanon that requires continuous EPP of HCWs, and a comprehensive approach for prevention and management.

Review of Thoracic Endovascular Aneurysm Repair (TEVAR), Spinal Cord Ischemia (SCI), Cerebrospinal Fluid (CSF) Drainage and Blood Pressure (BP) Augmentation

The object of this review is to examine the role of TEVAR in causing SCI. The anatomy and physiology of blood flow to the spinal cord is examined. The role of auto regulation of blood flow within the spinal cord is also examined. This review examines the reported results from the scientific literature of the effect of thoracic aortic aneurysm repair on spinal cord blood flow. In the light of the-se findings several conclusions can reasonably be reached. These conclusions are that the development of SCI can reasonably be predicted based on complexity and extent of the TEVAR procedure performed and BP augmentation and CSF drainage can significantly reduce the impact of SCI.

The Effect of Glucose Added to the Dialysis Fluid on Blood Pressure, Vasoactive Hormones and Energy Transfer during Hemodialysis in Chronic Renal Failure

Background: Previous studies showed that blood pressure was reduced in patients with chronic renal failure during hemodialysis with glucose added to the dialysis fluid. We wanted to test the hypotheses that blood pressure is reduced in non-diabetic and diabetic dialysis patients, when glucose is added to the dialysis fluid, and that blood pressure changes are caused by changes in plasma concentrations of vasoactive hormones or to vasodilation secondary to an increase in body temperature. Methods: The effect of dialysis with glucose added to the dialysis fluid was measured in three randomized, placebo-controlled, un-blinded and cross-over studies with periods of one week duration. In non-diabetic nephropathy (Study 1, n = 19) and diabetic nephropathy (Study 2, n = 15), we measured blood pressure (BP) and pulse rate (PR), plasma concentrations of glucose (p-Glucose), renin (PRC), angiotensin II (p-AngII), endothelin (p-Endot), insulin (p-Ins), glucagon (p-Glu), and human growth hormone (p-hGH). In non-diabetic nephropathy (Study 3, n = 24), we measured the effect of dialysis with glucose added to the dialysis fluid on energy transport from form the body using body temperature control. Results: Study 1 and 2 showed that BP, PRC, p-AngII, and p-Ins were unchanged, whereas P-Endot increased and P-hGH decreased, in dialysis patients with or without glucose added to the dialysis fluid. In diabetics, a marginal increase in p-Glu was measured during dialysis with glucose, but not without glucose. Study 3 showed that SBP increased significantly using dialysis with temperature control of dialysis fluid compared with no temperature control (145 versus 138 mm Hg). In parallel with the increase in SBP, the energy flux from the patients was significantly higher with temperature control than without. Conclusion: In non-diabetics and diabetics, blood pressure was unchanged during dialysis with glucose added to the dialysis fluid in a short-term study. Vasoactive hormones in plasma were changed in the same way independently of glucose in the dialysis fluid. Systolic blood pressure increased using dialysis with temperature control of dialysis fluid, presumably due to vasoconstriction to prevent or antagonize a fall in body temperature.

An Experimental Investigation on Rheological Properties of Aqueous Xanthan Gum as a Blood Analog Fluid

Developing a shear thinning non-Newtonian fluid to substitute blood is desirable in studies of biomedicine engineering since blood is a shear thinning non-Newtonian fluid that exhibits both viscous and elastic properties, and generally not available in large volume. The rheological properties of aqueous Xanthan gum with different concentrations and temperatures were studied in present paper. The results show that aqueous Xanthan gum is a non-Newtonian fluid which displays remarkable shear thinning behaviour and is a suitable blood analog fluid. There is a power law distribution relationship between shear stress and shear rate, and the higher the solution concentration is, the more strongly it displays shear thinning behaviours. Viscosity values of aqueous Xanthan gum increase with the solution temperature decrease or with the solution concentration increase in linearity. Moreover at the temperature of 37℃, aqueous Xanthan gum with concentration of 0.4‰ and 0.6‰ matches human blood best in rheological properties. According to the results, the viscosity expression varied with temperature and concentrition is obtained, and the stability of Xanthan gum solution is discussed.

主动脉穿刺型轴流血泵折边结构叶轮的数值模拟及溶血分析

为解决血泵因叶顶间隙泄漏而造成溶血和血栓等问题,引入了一种折边不等间距叶轮,采用计算流体力学(computational fluid dynamics, CFD)进行内部流场的数值模拟,并与非折边不等间距叶轮及折边等间距叶轮进行对比分析,研究了它们的内流场动力学特性和血液相容性.结果表明:折边叶片结构血泵避免了叶顶间隙泄漏流的产生,同时折边不等间距叶轮减少了叶轮入口和出口处的回流和涡流,流道内整体切应力低于其他2种叶轮;3种叶轮的溶血指数HI均满足血泵的溶血设计指标,其中,折边不等间距叶轮血泵壁面切应力在0~150 Pa的占比达96.84%,曝光时间相对集中且满足人工血泵设计要求,溶血指数较非折边不等间距叶轮血泵下降了3.50%,较折边等间距叶轮血泵下降了12.50%,溶血性能最优.提出的折边不等间距叶轮血泵可有效降低红细胞破损概率,减少溶血和血栓的发生,可为轴流血泵的结构设计和优化提供一定参考.

NFAT3在充血性心力衰竭气虚血瘀证患者舌苔液中的表达及意义

目的研究活化T细胞核因子3(nuclear factor of activated T-cells 3,NFAT3)在充血性心力衰竭(congestive heart failure,CHF)气虚血瘀证患者舌苔液中的表达及与临床指标相关性,初步拟定该证候的诊断界值。方法收集CHF气虚血瘀证患者及健康对照者各30例,酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)检测舌苔液中NFAT3的含量。结果NFAT3在CHF气虚血瘀证患者舌苔液的含量为(481.40±103.00)pg/mL,明显高于健康对照者舌苔液的含量[(237.90±156.50)pg/mL](P<0.01);且随着美国纽约心脏协会(New York Heart Association,NYHA)心功能分级的增加,CHF气虚血瘀证患者舌苔液中NFAT3含量不断升高(P<0.01);CHF气虚血瘀证患者舌苔液NFAT3与NYHA心功能分级呈正相关性(r=0.927,P<0.01),与B型脑钠肽(brain natriuretic peptide,BNP)(r=0.806,P<0.01)呈正相关性,与左室射血分数(left ventricular ejection fraction,LVEF)呈负相关性(r=-0.739,P<0.01)。绘制受试者操作特性曲线(receive operating characteristic,ROC)初步拟定舌苔液清中NFAT3诊断CHF气滞血瘀证的界值为363.37 pg/mL,曲线下面积为0.91。结论NFAT3能够反映CHF病情轻重程度,可为CHF气虚血瘀证提供客观化、量化的参考和依据。

基于表面增强拉曼光谱的肾结石患者体液代谢谱特点及应用价值

目的分析基于表面增强拉曼光谱(SERS)的肾结石患者体液代谢谱特点,探讨其应用价值,为肾结石患者的筛查工作提供参考。方法纳入福建省立医院泌尿外科确诊的25例肾结石患者(结石组)和25例健康体检者(对照组),采集其血液、尿液样本,利用SERS测量样本光谱,再进行平均谱和差异谱绘制。采用主成分分析结合线性判别分析(PCA-LDA)对归一化数据进行处理。最后采用受试者工作特征(ROC)曲线评估PCA-LDA方法的效能。结果结石组患者的体液(血液、尿液)拉曼光谱与对照组之间存在差异。根据既往报道的拉曼峰暂定分配,推测血浆和尿液中各有11种代谢物与肾结石有关,其中结石组尿液中的磷脂酰肌醇、苯丙氨酸、棕榈酸/脂肪酸等含量高于对照组,而尿嘧啶、糖原等成分的含量低于对照组。结石组患者血浆中的甲基带含量高于对照组,而糖原、磷脂酰肌醇、蛋白质-酪氨酸、苯丙氨酸、棕榈酸/脂肪酸、羟脯氨酸/酪氨酸和脂类的含量低于对照组。结论采用SERS检测可发现肾结石患者的尿液和血液代谢成分与健康体检者存在差异,结合PCA-LDA与ROC分析法可能有助于肾结石患者的筛查。