scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels and arterioles in the human microcirculation

2014 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Microfluidic Channel ◽  
Simulation Software ◽  
Time Dependent ◽  
Permeable Membrane ◽  
Micro Channels ◽  
Free Region ◽  
Channel Tube ◽  
The Right

The governing nonlinear equations for oxygen transport and ATP concentration in a microfluidic channel and tube are solved with the aid of Maple and COMSOL Multiphysics simulation software. Considering a cell-rich and cell free region with RBCs and blood plasma, we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed midway on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. Finally the corresponding time-dependent oxygen transport problem for plug flow in a channel, which has not been simulated in previous models in the literature, is analyzed and different starting times are shown for ATP release at different points in the channel. The FE modelling is very accurate: The time evolution problem is modelled and solved in it`s entirety with exact parameters used in the literature for blood flow and oxygen transport in the microcirculation. A comparison is made between the steady state and time dependent solutions in order to validate the results. The implications of the time dependent model for biological systems such as the human microcirculation requires exact information on release of energy as ATP is released from blood cells and the present work is important in providing this information.

scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels and arterioles in the human microcirculation

2014 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Microfluidic Channel ◽  
Simulation Software ◽  
Time Dependent ◽  
Permeable Membrane ◽  
Micro Channels ◽  
Free Region ◽  
Channel Tube ◽  
The Right

The governing nonlinear equations for oxygen transport and ATP concentration in a microfluidic channel and tube are solved with the aid of Maple and COMSOL Multiphysics simulation software. Considering a cell-rich and cell free region with RBCs and blood plasma, we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed midway on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. Finally the corresponding time-dependent oxygen transport problem for plug flow in a channel, which has not been simulated in previous models in the literature, is analyzed and different starting times are shown for ATP release at different points in the channel. The FE modelling is very accurate: The time evolution problem is modelled and solved in it`s entirety with exact parameters used in the literature for blood flow and oxygen transport in the microcirculation. A comparison is made between the steady state and time dependent solutions in order to validate the results. The implications of the time dependent model for biological systems such as the human microcirculation requires exact information on release of energy as ATP is released from blood cells and the present work is important in providing this information.

scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels

2015 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Microfluidic Channel ◽  
Permeable Membrane ◽  
Micro Channels ◽  
Free Region ◽  
Method Of Solution ◽  
Channel Tube ◽  
A Cell ◽  
The Right

The governing nonlinear steady equations for oxygen transport in a microfluidic channel are solved analytically. The Lagrange inversion theorem is used which admits complete integrable solutions in the channel. Considering a cell-rich and cell free region with RBCs and blood plasma, we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. The method of solution is compared to numerical results. The analytical results obtained could prove useful for the corresponding time dependent problem in future studies.

scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels

2015 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Microfluidic Channel ◽  
Permeable Membrane ◽  
Micro Channels ◽  
Free Region ◽  
Method Of Solution ◽  
Channel Tube ◽  
A Cell ◽  
The Right

The governing nonlinear steady equations for oxygen transport in a microfluidic channel are solved analytically. The Lagrange inversion theorem is used which admits complete integrable solutions in the channel. Considering a cell-rich and cell free region with RBCs and blood plasma, we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. The method of solution is compared to numerical results. The analytical results obtained could prove useful for the corresponding time dependent problem in future studies.

scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels and arterioles in the human microcirculation

2014 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Simulation Software ◽  
Time Dependent ◽  
Optimal Size ◽  
Permeable Membrane ◽  
Atp Concentration ◽  
Micro Channels ◽  
Channel Tube ◽  
The Right

The governing nonlinear equations for oxygen transport and ATP concentration in a microfluidic channel and tube are solved in a novel way with the aid of Maple and COMSOL Multiphysics simulation software. Considering a model which assumes a larger plasma velocity near the wall of a channel/tube in comparison to RBC velocity near the centerline we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed midway on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. It is shown that for smaller arterioles there is an optimal size for which greater amounts of ATP can be released. Finally the corresponding time-dependent oxygen transport problem for plug flow in a channel, which has not been simulated in previous models in the literature, is analyzed and different starting times are shown for ATP release at different points in the channel. The FE modelling is very accurate: The time evolution problem is modelled and solved in it`s entirety with exact parameters used in the literature for blood flow and oxygen transport in the microcirculation. A comparison is made between the steady state and time dependent solutions in order to validate the results. The implications of the time dependent model for biological systems such as the human microcirculation requires exact information on release of energy as ATP is released from blood cells and the present work is important in providing this information. In particular, the time varying problem for ATP concentration and it’s temporal dynamics, as calculated in this paper is crucial in determining the ADP/ATP concentration pair which is an oscillating pair in the biochemical oscillations that occur in glycolysis in anaerobic yeast cultures.

scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels and arterioles in the human microcirculation

2014 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Simulation Software ◽  
Time Dependent ◽  
Optimal Size ◽  
Permeable Membrane ◽  
Atp Concentration ◽  
Micro Channels ◽  
Channel Tube ◽  
The Right

The governing nonlinear equations for oxygen transport and ATP concentration in a microfluidic channel and tube are solved in a novel way with the aid of Maple and COMSOL Multiphysics simulation software. Considering a model which assumes a larger plasma velocity near the wall of a channel/tube in comparison to RBC velocity near the centerline we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed midway on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. It is shown that for smaller arterioles there is an optimal size for which greater amounts of ATP can be released. Finally the corresponding time-dependent oxygen transport problem for plug flow in a channel, which has not been simulated in previous models in the literature, is analyzed and different starting times are shown for ATP release at different points in the channel. The FE modelling is very accurate: The time evolution problem is modelled and solved in it`s entirety with exact parameters used in the literature for blood flow and oxygen transport in the microcirculation. A comparison is made between the steady state and time dependent solutions in order to validate the results. The implications of the time dependent model for biological systems such as the human microcirculation requires exact information on release of energy as ATP is released from blood cells and the present work is important in providing this information. In particular, the time varying problem for ATP concentration and it’s temporal dynamics, as calculated in this paper is crucial in determining the ADP/ATP concentration pair which is an oscillating pair in the biochemical oscillations that occur in glycolysis in anaerobic yeast cultures.

Symmetrizable Difference Dchemes

2005 ◽  
Vol 5 (1) ◽  
pp. 3-50 ◽  
Author(s):  
Alexei A. Gulin
Keyword(s):  
Initial Data ◽  
Difference Scheme ◽  
Difference Schemes ◽  
Time Dependent ◽  
Stability Boundaries ◽  
Typical Representative ◽  
Variable Weight ◽  
The Stability ◽  
Conditions Of Stability ◽  
The Right

AbstractA review of the stability theory of symmetrizable time-dependent difference schemes is represented. The notion of the operator-difference scheme is introduced and general ideas about stability in the sense of the initial data and in the sense of the right hand side are formulated. Further, the so-called symmetrizable difference schemes are considered in detail for which we manage to formulate the unimprovable necessary and su±cient conditions of stability in the sense of the initial data. The schemes with variable weight multipliers are a typical representative of symmetrizable difference schemes. For such schemes a numerical algorithm is proposed and realized for constructing stability boundaries.

scholarly journals Right-sided Bochdalek hernia in an adult with hepatic malformation and intestinal malrotation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Naoki Enomoto ◽  
Kazuhiko Yamada ◽  
Daiki Kato ◽  
Shusuke Yagi ◽  
Hitomi Wake ◽  
...  
Keyword(s):  
Elective Surgery ◽  
Abdominal Cavity ◽  
Three Dimensional ◽  
Simulation Software ◽  
3D Simulation ◽  
Diaphragmatic Defect ◽  
Intestinal Malrotation ◽  
Intestinal Loop ◽  
Bochdalek Hernia ◽  
The Right

Abstract Background Bochdalek hernia is a common congenital diaphragmatic defect that usually manifests with cardiopulmonary insufficiency in neonates. It is very rare in adults, and symptomatic cases are mostly left-sided. Diaphragmatic defects generally warrant immediate surgical intervention to reduce the risk of incarceration or strangulation of the displaced viscera. Case presentation A 47-year-old woman presented with dyspnea on exertion. Computed tomography revealed that a large part of the intestinal loop with superior mesenteric vessels and the right kidney were displaced into the right thoracic cavity. Preoperative three-dimensional (3D) simulation software visualized detailed anatomy of displaced viscera and the precise location and size of the diaphragmatic defect. She underwent elective surgery after concomitant pulmonary hypertension was stabilized preoperatively. The laparotomic approach was adopted. Malformation of the liver and the presence of intestinal malrotation were confirmed during the operation. The distal part of the duodenum, jejunum, ileum, colon, and right kidney were reduced into the abdominal cavity consecutively. A large-sized oval defect was closed with monofilament polypropylene mesh. No complications occurred postoperatively. Conclusion Symptomatic right-sided Bochdalek hernia in adults is exceedingly rare and is frequently accompanied by various visceral anomalies. Accurate diagnosis and appropriate surgical repair are crucial to prevent possible incarceration or strangulation. The preoperative 3D simulation provided comprehensive information on anatomy and concomitant anomalies and helped surgeons plan the operation meticulously and perform procedures safely.

scholarly journals Non-Stationary Model of Cerebral Oxygen Transport with Unknown Sources

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 910
Author(s):  
Andrey Kovtanyuk ◽  
Alexander Chebotarev ◽  
Varvara Turova ◽  
Irina Sidorenko ◽  
Renée Lampe
Keyword(s):  
Inverse Problem ◽  
Oxygen Transport ◽  
Model Parameters ◽  
Cerebral Oxygen ◽  
System Of Equations ◽  
Blood Oxygen ◽  
Stationary Model ◽  
Average Oxygen Concentration ◽  
The Right ◽  
The Brain

An inverse problem for a system of equations modeling oxygen transport in the brain is studied. The problem consists of finding the right-hand side of the equation for the blood oxygen transport, which is a linear combination of given functionals describing the average oxygen concentration in the neighborhoods of the ends of arterioles and venules. The overdetermination condition is determined by the values of these functionals evaluated on the solution. The unique solvability of the problem is proven without any smallness assumptions on the model parameters.

La recherche appliquée: le cas du « Katholiek Sociaal Kerkelijk Instituut (KASKI) » aux Pays-Bas

1971 ◽  
Vol 18 (4) ◽  
pp. 621-637 ◽  
Author(s):  
Adolf Holl ◽  
Hyacinthe Crépin
Keyword(s):  
Professional Competence ◽  
Rapid Change ◽  
Religious Life ◽  
Religious Practice ◽  
The Political ◽  
Religious Groups ◽  
The People ◽  
Pastoral Planning ◽  
Senior Research ◽  
The Right

Following Vatican II changes are rapidly taking place within Dutch Catholicism — the bishops no longer make decisions in an authoritarian way: religious practice is de clining ; priests and religious are decreasing in numbers and many religious and pastoral experiments have come into being. KASKI has the responsibility of keeping pace with the Church during this process of change. In order to do this it makes use of several modes of work — the production of statistics relating to the position of religion in Society, the planning of religious and pastoral institutions and the study of new forms of the religious life in orders and congregations. For the first task it has used the same instruments for twenty- five years and the censuses thus produced yield valuable infor mation. As far as pastoral planning is concerned, it works in the field, playing the role of catalyst for those who have to make decisions and the people who have to carry out these decisions. This was the case, for instance, in the pastoral planning of the town of Eindhoven. Finally, when dealing with the new forms of communal religious life it adopts the method of studying through participation so that two of its researchers working in this sector are themselves members of religious groups. Applied research poses important problems, both from the methodological and from the political points of view. Amongst them may be noted the difficulty of determining precisely what constitutes rapid change in religious life, and the political choice of the persons for whom the research is being con ducted; the latter inevitably imposes a certain degree of conformity upon the perspectives of the work. (For example, the choice of the Dutch hierarchy which was to follow the general lines given by a large majority of Catholic opinion when it was tested particularly on questions like the liturgical and parochial changes). The fact, also, that the director of KASKI himself has a personal commitment to what may be described as the « right of centre » position in Dutch Catho licism poses problems for the work of the Institute. Political and religious radicalism is not a strong characteristic of the more senior research workers. KASKI is a rare example of a centre which brings socio logists together and uses their professional competence to accompany change in religious institutions.

scholarly journals COMPARISON OF BASIC MAINTENANCE CONCEPTS USING WITNESS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5435-5440
Author(s):  
VLADIMIRA SCHINDLEROVA ◽  
◽  
IVANA SAJDLEROVA ◽  
Keyword(s):  
21St Century ◽  
Simulation Software ◽  
Predictive Maintenance ◽  
Maintenance Management ◽  
Practical Application ◽  
Manufactured Products ◽  
The Right ◽  
Positive Effect ◽  
Production Facilities

Maintenance is a complex, extensive and important issue in terms of its impact on the quality of manufactured products or services provided in all areas of industry. The importance of predictive maintenance for the industry in the 21st century is crucial. However, the right approach to maintenance management is often underestimated in many companies today, although it can have a very positive effect on the company’s efficiency. Using the example of a practical application, the paper includes a comparison of three main maintenance concepts – classical (reactive), planned, predictive through the simulation software Witness. Maintenance concepts are compared in terms of their ability to solve and eliminate failures that occur in production facilities during operation.

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