scholarly journals A mathematical model of mitochondrial calcium-phosphate dissolution as a mechanism for persistent post-CSD vasoconstriction

2019 ◽  
Author(s):  
Shixin Xu ◽  
Joshua C. Chang ◽  
Carson C. Chow ◽  
Huaxiong Huang
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Calcium Phosphate ◽  
Mitochondrial Calcium ◽  
Short Term ◽  
Pathological Conditions ◽  
Calcium Clearance ◽  
Phosphate Dissolution ◽  
Ion Shifts ◽  
Reaction Stoichiometry

AbstractCortical spreading depolarization (CSD) is the propagation of a relatively slow wave in cortical brain tissue that is linked to a number of pathological conditions such as stroke and migraine. Most of the existing literature investigates the dynamics of short term phenomena such as the depolarization and repolarization of membrane potentials or large ion shifts. Here, we focus on the clinically-relevant hour-long state of neurovascular malfunction in the wake of CSDs. This dysfunctional state involves widespread vasoconstriction and a general disruption of neurovascular coupling. We demonstrate, using a mathematical model, that dissolution of calcium that has aggregated within the mitochondria of vascular smooth muscle cells can drive an hour-long disruption. We determine the rate of calcium clearance as well as the dynamical implications on overall blood flow. Based on reaction stoichiometry, we quantify a possible impact of calcium phosphate dissolution on the maintenance of F0F1-ATP synthase activity.

EXPERIMENTAL STUDIES OF CAR PROPERTIES ON A PHYSICAL MODEL

2019 ◽  
pp. 10-16
Author(s):  
Oleksii Timkov ◽  
Dmytro Yashchenko ◽  
Volodymyr Bosenko
Keyword(s):  
Mathematical Model ◽  
Remote Control ◽  
Physical Model ◽  
Model Experiment ◽  
Experimental Studies ◽  
Electrical Energy ◽  
Short Term ◽  
Motor Current ◽  
Memory Card ◽  
The Mathematical Model

The article deals with the development of a physical model of a car equipped with measuring, recording and remote control equipment for experimental study of car properties. A detailed description of the design of the physical model and of the electronic modules used is given, links to application libraries and the code of the first part of the program for remote control of the model are given. Atmega microcontroller on the Arduino Uno platform was used to manage the model and register the parameters. When moving the car on the memory card saved such parameters as speed, voltage on the motor, current on the motor, the angle of the steered wheel, acceleration along three coordinate axes are recorded. Use of more powerful microcontrollers will allow to expand the list of the registered parameters of movement of the car. It is possible to measure the forces acting on the elements of the car and other parameters. In the future, it is planned to develop a mathematical model of motion of the car and check its adequacy in conducting experimental studies on maneuverability on the physical model. In addition, it is possible to conduct studies of stability and consumption of electrical energy. The physical model allows to quickly change geometric dimensions and mass parameters. In the study of highway trains, this approach will allow to investigate the various layout schemes of highway trains in the short term. It is possible to make two-axle road trains and saddle towed trains, three-way hitched trains of different layout. The results obtained will allow us to improve not only the mathematical model, but also the experimental physical model, and move on to further study the properties of hybrid road trains with an active trailer link. This approach allows to reduce material and time costs when researching the properties of cars and road trains. Keywords: car, physical model, experiment, road trains, sensor, remote control, maneuverability, stability.

scholarly journals WALANT–Epinephrine injection may lead to short term, reversible episodes of critical oxygen saturation in the fingertips

2021 ◽  
Vol 141 (3) ◽  
pp. 527-533
Author(s):  
P. Moog ◽  
M. Dozan ◽  
J. Betzl ◽  
I. Sukhova ◽  
H. Kükrek ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Substantial Reduction ◽  
Tissue Perfusion ◽  
Critical Levels ◽  
Short Term ◽  
Doppler Flowmetry ◽  
Epinephrine Injection ◽  
Venous Oxygen Saturation

Abstract Introduction Although the WALANT technique’s long-term safeness has been demonstrated in many studies, there are only few data investigating its short-term effects on tissue perfusion and oxygen levels. It was hypothesized that, temporarily, critical levels of tissue perfusion may occur. Methods Seventeen patients, who were scheduled for different procedures in WALANT technique, were injected with 5–7 ml of 1% Articain containing 1:200,000 epinephrine at the finger base. Capillary-venous oxygen saturation, hemoglobin volume in the capillaries, and relative blood flow in the fingertips were recorded once per second by white light spectrometry and laser Doppler flowmetry before, during and after injection for an average of 32 min. Results Clinically, no persistent tissue malperfusion was observed, and there were no postoperative complications. Capillary-venous oxygen saturation was reduced by ≥ 30% in seven patients. Critical levels of oxygen saturation were detected in four patients during 13 intervals, each lasting for 132.5 s on average. Oxygen saturation returned to noncritical values in all patients by the end of the observation period. Blood flow in the fingertips was reduced by more than 30% in nine patients, but no critical levels were observed, as with the hemoglobin. Three patients demonstrated a reactive increase in blood flow of more than 30% after injection. Conclusions Injection of tumescent local anesthesia containing epinephrine into finger base may temporarily cause a substantial reduction in blood flow and lead to critical levels of oxygen saturation in the fingertips. However, this was fully reversible within minutes and does not cause long-term complications.

scholarly journals Short-Term Tolvaptan Increases Water Intake and Effectively Decreases Urinary Calcium Oxalate, Calcium Phosphate and Uric Acid Supersaturations

2016 ◽  
Vol 195 (5) ◽  
pp. 1476-1481 ◽  
Author(s):  
Wisit Cheungpasitporn ◽  
Stephen B. Erickson ◽  
Andrew D. Rule ◽  
Felicity Enders ◽  
John C. Lieske
Keyword(s):  
Uric Acid ◽  
Calcium Phosphate ◽  
Calcium Oxalate ◽  
Water Intake ◽  
Urinary Calcium ◽  
Short Term

A MATHEMATICAL MODEL OF ANEURYSM OF CIRCLE OF WILLIS

1995 ◽  
Vol 03 (03) ◽  
pp. 653-659 ◽  
Author(s):  
J. J. NIETO ◽  
A. TORRES
Keyword(s):  
Differential Equation ◽  
Mathematical Model ◽  
Ordinary Differential Equation ◽  
Blood Flow ◽  
Nonlinear Analysis ◽  
Existence Of Solutions ◽  
Circle Of Willis ◽  
Second Order ◽  
Qualitative Properties

We introduce a new mathematical model of aneurysm of the circle of Willis. It is an ordinary differential equation of second order that regulates the velocity of blood flow inside the aneurysm. By using some recent methods of nonlinear analysis, we prove the existence of solutions with some qualitative properties that give information on the causes of rupture of the aneurysm.

Short-term treatment with hepatoselective NO donor V-PYRRO/NO improves blood flow in hepatic microcirculation in liver steatosis in mice

2018 ◽  
Vol 70 (3) ◽  
pp. 463-469 ◽  
Author(s):  
Edyta Kus ◽  
Krzysztof Jasiński ◽  
Tomasz Skórka ◽  
Izabela Czyzynska-Cichon ◽  
Stefan Chlopicki
Keyword(s):  
Blood Flow ◽  
Liver Steatosis ◽  
Term Treatment ◽  
Short Term ◽  
Short Term Treatment ◽  
Hepatic Microcirculation ◽  
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