scholarly journals Patient Specific Numerical Modeling for Renal Blood Monitoring Using Electrical Bio-Impedance

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 606
Author(s):  
Mugeb Al-harosh ◽  
Egor Chernikov ◽  
Sergey Shchukin
Keyword(s):  
Numerical Modelling ◽  
Blood Circulation ◽  
Electrical Impedance ◽  
Experimental Studies ◽  
Skin Surface ◽  
Electrode System ◽  
Patient Specific ◽  
Impedance Change ◽  
Blood Distribution ◽  
Hemodynamic Characteristics

Knowledge of renal blood circulation is considered as an important physiological value, particularly for fast detection of acute allograft rejection as well as the management of critically ill patients with acute renal failure. The electrical impedance signal obtained from kidney with an appropriate electrode system and optimal electrode system position regarding to the kidney projection on skin surface reflects the nature of renal blood circulation and tone of renal blood vessels. This paper proposes a specific numerical modelling based on prior information from MRI-data. The numerical modelling was conducted for electrical impedance change estimation due to renal blood distribution. The proposed model takes into the account the geometrical and electrophysiological parameters of tissues around the kidney as well as the actual blood distribution within the kidney. The numerical modelling had shown that it is possible to register the electrical impedance signal caused by renal blood circulation with an electrode system commensurate with the size of kidney, which makes it possible to reduce the influence of surrounding tissues and organs. Experimental studies were obtained to prove the numerical modelling and the effectiveness of developed electrode systems based on the obtained simulation results. The obtained electrical impedance signal with the appropriate electrode system shows very good agreement with the renal blood change estimated using Doppler ultrasound. For the measured electrical impedance signal, it is possible to obtain the amplitude-time parameters, which reflect the hemodynamic characteristics of the kidneys and used in diagnostics, which is the subject of further research.

scholarly journals Smart Bio-Impedance-Based Sensor for Guiding Standard Needle Insertion

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 665
Author(s):  
Ivan Kudashov ◽  
Sergey Shchukin ◽  
Mugeb Al-harosh ◽  
Andrew Shcherbachev
Keyword(s):  
Electrical Impedance ◽  
Experimental Studies ◽  
Needle Insertion ◽  
Electrode System ◽  
Medical Procedure ◽  
Peripheral Vascular ◽  
Non Invasive ◽  
Invasive Medical Procedure ◽  
Time Parameters ◽  
Tip Position

A venipuncture is the most common non-invasive medical procedure, and is frequently used with patients; however, a high probability of post-injection complications accompanies intravenous injection. The most common complication is a hematoma, which is associated with puncture of the uppermost and lowermost walls. To simplify and reduce complications of the venipuncture procedure, and as well as automation of this process, a device that can provide information of the needle tip position into patient’s tissues needs to be developed. This paper presents a peripheral vascular puncture control system based on electrical impedance measurements. A special electrode system was designed to achieve the maximum sensitivity for puncture identification using a traditional needle, which is usually used in clinical practice. An experimental study on subjects showed that the electrical impedance signal changed significantly once the standard needle entered the blood vessel. On basis of theoretical and experimental studies, a decision rule of puncture identification based on the analysis of amplitude-time parameters of experimental signals was proposed. The proposed method was tested on 15 test and 9 control samples, with the results showing that 97% accuracy was obtained.

scholarly journals Computational and experimental mechanical performance of a new everolimus-eluting stent purpose-built for left main interventions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saurabhi Samant ◽  
Wei Wu ◽  
Shijia Zhao ◽  
Behram Khan ◽  
Mohammadali Sharzehee ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Patient Specific ◽  
Wall Structure ◽  
Left Main ◽  
Element Analysis ◽  
Stent Expansion ◽  
Radial Strength ◽  
Different Diameters

AbstractLeft main (LM) coronary artery bifurcation stenting is a challenging topic due to the distinct anatomy and wall structure of LM. In this work, we investigated computationally and experimentally the mechanical performance of a novel everolimus-eluting stent (SYNERGY MEGATRON) purpose-built for interventions to large proximal coronary segments, including LM. MEGATRON stent has been purposefully designed to sustain its structural integrity at higher expansion diameters and to provide optimal lumen coverage. Four patient-specific LM geometries were 3D reconstructed and stented computationally with finite element analysis in a well-validated computational stent simulation platform under different homogeneous and heterogeneous plaque conditions. Four different everolimus-eluting stent designs (9-peak prototype MEGATRON, 10-peak prototype MEGATRON, 12-peak MEGATRON, and SYNERGY) were deployed computationally in all bifurcation geometries at three different diameters (i.e., 3.5, 4.5, and 5.0 mm). The stent designs were also expanded experimentally from 3.5 to 5.0 mm (blind analysis). Stent morphometric and biomechanical indices were calculated in the computational and experimental studies. In the computational studies the 12-peak MEGATRON exhibited significantly greater expansion, better scaffolding, smaller vessel prolapse, and greater radial strength (expressed as normalized hoop force) than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY (p < 0.05). Larger stent expansion diameters had significantly better radial strength and worse scaffolding than smaller stent diameters (p < 0.001). Computational stenting showed comparable scaffolding and radial strength with experimental stenting. 12-peak MEGATRON exhibited better mechanical performance than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY. Patient-specific computational LM stenting simulations can accurately reproduce experimental stent testing, providing an attractive framework for cost- and time-effective stent research and development.

Medicinal correction of cerebrovascular reactivity — a necessary component of the treatment of cerebral blood circulation disorders

1999 ◽  
Vol 80 (2) ◽  
pp. 94-96
Author(s):  
V. I. Danilov
Keyword(s):  
Blood Circulation ◽  
Organic Phosphorus ◽  
Experimental Studies ◽  
Cerebrovascular Reactivity ◽  
Cerebral Vessels ◽  
Regulatory Mechanisms ◽  
Phosphorus Compounds ◽  
Low Toxic ◽  
The Brain ◽  
Cerebral Blood Circulation

The results of experimental studies made it possible to draw a conclusion on the reality of cerebral vessels reactivity recovery using drugs with primary neurometabolic activity, in particular, dimephosphone, sermion and pyracetam. The advantages of low-toxic nonauticholinesterasic organic phosphorus compounds among the correctors of regulatory mechanisms of circular provision of the brain are shown.

scholarly journals Experimental studies and numerical modelling of heat and mass transfer process in shell-and-tube heat exchangers with compact arrangements of tube bundles

2018 ◽  
Vol 240 ◽  
pp. 02006 ◽  
Author(s):  
Valery Gorobets ◽  
Yurii Bohdan ◽  
Viktor Trokhaniak ◽  
Ievgen Antypov
Keyword(s):  
Mass Transfer ◽  
Numerical Modelling ◽  
Heat And Mass Transfer ◽  
Heat Exchangers ◽  
Experimental Studies ◽  
Mass Transfer Process ◽  
Experimental Investigations ◽  
Transfer Processes ◽  
Tube Bundles ◽  
Shell And Tube

Shall-and-tube heat exchangers based on the bundles with in-line or staggered arrangements have been widely used in industry and power engineering. A large number of theoretical and experimental works are devoted to study of hydrodynamic and heat transfer processes in such bundles. In that, works the basic studies of heat and mass transfer for these bundles are found. However, heat exchangers of this type can have big dimensions and mass. One of the ways to improve the weight and dimensions of the shell-and-tube heat exchangers is to use compact arrangement of tube bundles. A new design of heat exchanger is proposed, in which there are no gaps between adjacent tubes that touch each other. Different geometry of these tube bundles with displacement of adjacent tubes in the direction of transverse to the flow is considered. Numerical modelling and experimental investigations of hydrodynamic, heat and mass transfer processes in such tube bundles has been carried out. The distribution of velocities, temperatures, and pressure in inter-tube channels have been obtained.

scholarly journals Numerical simulations of patient-specific models with multiple plaques in human peripheral artery: a fluid-structure interaction analysis

2020 ◽  
Author(s):  
Danyang Wang ◽  
Ferdinand Serracino-Inglott ◽  
Jiling Feng
Keyword(s):  
Interaction Analysis ◽  
Experimental Studies ◽  
Specific Model ◽  
Patient Specific ◽  
Peripheral Artery ◽  
Fluid Structure ◽  
Femoral Arteries ◽  
Risk Of Rupture ◽  
Artery Disease ◽  
Hemodynamic Performance

Abstract Atherosclerotic plaque in the femoral is the leading cause of peripheral artery disease (PAD), the worse consequence of which may lead to ulceration and gangrene of the feet. Numerical studies on fluid-structure interactions (FSI) of atherosclerotic femoral arteries enable quantitative analysis of biomechanical features in arteries. This study aims to investigate the hemodynamic performance and its interaction with femoral arterial wall based on the patient-specific model with multiple plaques (calcified and lipid plaques). Three types of models, calcification-only, lipid-only and calcification-lipid models, are established. Hyperelastic material coefficients of the human femoral arteries obtained from experimental studies are employed for all simulations. Oscillation of WSS is observed in the healthy downstream region in the lipid-only model. The pressure around the plaques in the two-plaque model is lower than that in the corresponding one-plaque models due to the reduction of blood flow domain, which consequently diminishes the loading forces on both plaques. Therefore, we found that stress acting on the plaques in the two-plaque model is lower than that in the corresponding one-plaque models. This finding implies that the lipid plaque, accompanied by the calcified plaque around, might reduce its risk of rupture due to the reduced the stress acting on it.

Determination of reactional cutting forces on a circular sawblade machine by using experimental studies and numerical modelling

2011 ◽  
Vol 226 (3) ◽  
pp. 775-784 ◽  
Author(s):  
N E Yasitli ◽  
F Bayram ◽  
B Unver ◽  
Y Ozcelik
Keyword(s):  
Numerical Modelling ◽  
Cutting Forces ◽  
Numerical Models ◽  
Experimental Studies ◽  
Cutting Parameters ◽  
Element Model ◽  
Natural Stone ◽  
Processing Plants ◽  
Cutting Operation ◽  
Stone Cutting

Slab/strip production from blocks in natural stone processing plants is mostly carried out by using circular sawblade cutting machines. An efficient sawing operation can only be maintained by selecting proper cutting parameters. Experimental studies and numerical modelling methods are significant in terms of identifying the effective forces occurring during natural stone cutting with circular sawblades. In this study, experimental investigation was performed on real marble, known as Afyon White Marble, using a fully automatic circular sawblade stone cutting machine. Then, numerical modelling of circular sawing was performed with commercially available software called PFC3D. A discrete-element model of the sawing process was developed, and various numerical models were performed for different peripheral speeds and advance rates in compliance with the actual cutting operation being carried out in the laboratory. Finally, data obtained from the experimental studies were compared with the modelling data. A comparison indicates that the reactional cutting forces obtained by means of the numerical modelling are in good agreement with the results of the laboratory measurements. Consequently, the cutting operation can be determined quickly and economically. A literature review showed that, through this study, numerical modelling of the circular sawblade stone cutting process was successfully performed for the first time. It was envisaged that this would dynamically help in the examination of distinct factors in the area of natural stone processing by numerical modelling and in the illustration of the sawing mechanism.

scholarly journals Improved system for identifying biological tissue temperature using electrical impedance tomography

2018 ◽  
Vol 158 ◽  
pp. 01019 ◽  
Author(s):  
Evgeniy Korolyuk ◽  
Konstantin Brazovskii
Keyword(s):  
Electrical Impedance ◽  
Saline Water ◽  
Broad Band ◽  
Experimental Studies ◽  
Impedance Spectrum ◽  
Target Object ◽  
Tissue Temperature ◽  
Band Spectrum ◽  
Measuring Chamber ◽  
Impedance Tomography

This paper proposes a cheap and compact medical system that determines the temperature of an object using broadband impedance tomography. This system can be used in medicine to visualize ice structure in tissue during cryosurgical operations, as well as for fault diagnosis and location in studied industrial objects. These effects are achieved by measuring electrical impedance between electrode pairs in the measuring chamber. The assembled prototype is compact, consumes little power, and allows to non-invasively determine the impedance of a target object in real time. The research included experimental studies to determine the dependence of the impedance spectrum of saline water and muscle tissue on temperature in broad band spectrum, which allowed to obtain the dependence of total electrical impedance of target objects on temperature.

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