scholarly journals Mathematical model reveals that heterogeneity in the number of ion transporters regulates the fraction of mouse sperm capacitation

2021 ◽  
Author(s):  
Alejandro Aguado-García ◽  
Daniel A. Priego-Espinosa ◽  
Andrés Aldana ◽  
Alberto Darszon ◽  
Gustavo Martínez-Mekler
Keyword(s):  
Mathematical Model ◽  
Experimental Verification ◽  
Intracellular Signaling ◽  
Female Genital Tract ◽  
Experimental Studies ◽  
Fertility Control ◽  
Experimental Results ◽  
Loss Of Function ◽  
Ion Transporters ◽  
Individual Number

AbstractCapacitation is a complex maturation process that mammalian sperm must undergo in the female genital tract to be able to fertilize an egg. This process involves, amongst others, physiological changes in flagellar beating pattern, membrane potential, intracellular ion concentrations and protein phosphorylation. Typically, in a capacitation medium, only a fraction of sperm achieve this state. The cause for this heterogeneous response is still not well understood and remains an open question. Here, one of our principal results is to develop a discrete regulatory network, with mostly deterministic dynamics in conjunction with some stochastic elements, for the main biochemical and biophysical processes involved in the early events of capacitation. The model criterion for capacitation requires the convergence of specific levels of a select set of nodes. Besides reproducing several experimental results and providing some insight on the network interrelations, the main contribution of the model is the suggestion that the degree of variability in the total amount and individual number of ion transporters among spermatozoa regulates the fraction of capacitated spermatozoa. This conclusion is consistent with recently reported experimental results. Based on this mathematical analysis, experimental clues are proposed for the control of capacitation levels. Furthermore, synergistic and interference traits that become apparent in the modelling among some components also call for future theoretical and experimental studies.Author SummaryFertilization is one of the fundamental processes for the preservation of life. In mammals sperms undergo a complex process during their passage through the female tract known as capacitation which enables them for fertilization. At the present time it is accepted from experimental observation, though not understood, is that only a fraction of the sperm is capacitated. In this work, by means of a network mathematical model for regulatory spermatozoa intracellular signaling processes involved in mice capacitation, we find that the variability in the distribution of the number of ion transporters intervenes in the regulation of the capacitation fraction. Experimental verification of this suggestion could open a line of research geared to the regulation of the degree of heterogeneity in the number of ion transporters as a fertility control. The model also uncovers through in silico hyperactivation, loss of function and knockout of network elements, synergetic traits which again call for experimental verification.

scholarly journals Mathematical model reveals that heterogeneity in the number of ion transporters regulates the fraction of mouse sperm capacitation

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0245816
Author(s):  
Alejandro Aguado-García ◽  
Daniel A. Priego-Espinosa ◽  
Andrés Aldana ◽  
Alberto Darszon ◽  
Gustavo Martínez-Mekler
Keyword(s):  
Female Genital Tract ◽  
Experimental Studies ◽  
Experimental Results ◽  
Ion Transporters ◽  
Mammalian Sperm ◽  
Individual Number ◽  
Biophysical Processes ◽  
Intracellular Ion Concentrations ◽  
Open Question ◽  
Female Genital

Capacitation is a complex maturation process mammalian sperm must undergo in the female genital tract to be able to fertilize an egg. This process involves, amongst others, physiological changes in flagellar beating pattern, membrane potential, intracellular ion concentrations and protein phosphorylation. Typically, in a capacitation medium, only a fraction of sperm achieve this state. The cause for this heterogeneous response is still not well understood and remains an open question. Here, one of our principal results is to develop a discrete regulatory network, with mostly deterministic dynamics in conjunction with some stochastic elements, for the main biochemical and biophysical processes involved in the early events of capacitation. The model criterion for capacitation requires the convergence of specific levels of a select set of nodes. Besides reproducing several experimental results and providing some insight on the network interrelations, the main contribution of the model is the suggestion that the degree of variability in the total amount and individual number of ion transporters among spermatozoa regulates the fraction of capacitated spermatozoa. This conclusion is consistent with recently reported experimental results. Based on this mathematical analysis, experimental clues are proposed for the control of capacitation levels. Furthermore, cooperative and interference traits that become apparent in the modelling among some components also call for future theoretical and experimental studies.

scholarly journals Modeling of Pressure Drop During Refrigerant Condensation in Pipe Minichannels

2017 ◽  
Vol 38 (4) ◽  
pp. 15-28 ◽  
Author(s):  
Małgorzata Sikora ◽  
Tadeusz Bohdal
Keyword(s):  
Mathematical Model ◽  
Pressure Drop ◽  
Computer Modeling ◽  
Experimental Verification ◽  
Flow Resistance ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Flow Conditions ◽  
Conservation Equations ◽  
Mathematical And Computer Modeling

Abstract Investigations of refrigerant condensation in pipe minichannels are very challenging and complicated issue. Due to the multitude of influences very important is mathematical and computer modeling. Its allows for performing calculations for many different refrigerants under different flow conditions. A large number of experimental results published in the literature allows for experimental verification of correctness of the models. In this work is presented a mathematical model for calculation of flow resistance during condensation of refrigerants in the pipe minichannel. The model was developed in environment based on conservation equations. The results of calculations were verified by authors own experimental investigations results.

Emission Control Through Cu-Exchanged X-Zeolite Catalysts: Experimental Studies and Theoretical Modeling

1999 ◽  
Vol 122 (1) ◽  
pp. 106-111
Author(s):  
S. Bhattacharyya ◽  
R. K. Das
Keyword(s):  
Mathematical Model ◽  
Noble Metals ◽  
Copper Ions ◽  
Nox Reduction ◽  
Experimental Studies ◽  
Back Pressure ◽  
Experimental Results ◽  
Zeolite Catalysts ◽  
Average Deviation ◽  
X Zeolite

Catalysts based on X-zeolite have been developed by exchanging its Na+ ion with Copper ions and its effectiveness in reducing NOx in an actual SI engine exhaust has been tested. Unlike noble metals, the doped X-zeolite catalysts, studied here, exhibit significant NOx reduction for a wide λ range and exhibit a slow rate of decrease with increase in λ ratio. Back pressure developed across the catalyst bed was found to be well-affordable and power loss due to back pressure is only minimal. During 30 hours of testing of the catalyst, no significant deactivation was observed. Additionally a mathematical model has been developed to predict the performance of the catalyst and to validate that against experimental results. Results predicted by the mathematical model agree well with the experimental results and absolute average deviation of experimental conversion efficiency is found to be less than 5 percent of the predicted value. [S0742-4795(00)01601-X]

Experimental verification of a mathematical model of a computer effusion decreasing discharge pressure gas density analyzer

2020 ◽  
pp. 57-63
Author(s):  
Stanislav Yu. Zhigulin ◽  
Leonid V. Iliasov
Keyword(s):  
Mathematical Model ◽  
Model Test ◽  
Experimental Verification ◽  
Experimental Studies ◽  
Calculated Data ◽  
Effect Of Temperature ◽  
Experimental Setup ◽  
Gas Density ◽  
Discharge Pressure ◽  
The Mathematical Model

The article presents the results of checking mathematical model of the created decreasing pressure effusion computer gas density analyzer. Operating principle of a decreasing pressure effusion gas density analyzers is based on measuring the outflow time of the analyzed gas certain volume through a microdiaphragm. A generalized scheme of such analyzers and their operation are described in article. Initial equations of the mathematical model, the assumptions and the results of the development of the mathematical model are presented. The created experimental setup for testing the developed mathematical model and its operation also are described. The mathematical model was tested in the course of numerous experiments on this facility for a number of gases. Studies have also been performed to assess the effect of temperature on the measurement result. The results of the mathematical model test are presented in the article. The results of experimental studies were compared with the calculated data obtained on the basis of a mathematical model. As a result, the error of the mathematical model of the decreasing pressure effusion gas density analyzers was determined and conclusions were made about its adequacy and possible further use for designing and calculating decreasing pressure effusion gas density analyzers.

scholarly journals Taking into account of natural and technological aspects of sustainable development of the forest complex when choosing a harvester manipulator

2020 ◽  
Vol 208 ◽  
pp. 01006
Author(s):  
Sergey Karpachev ◽  
Maksim Bykovskiy
Keyword(s):  
Mathematical Model ◽  
Sustainable Development ◽  
Experimental Studies ◽  
Experimental Results ◽  
Wood Volume ◽  
Technological Factors ◽  
Machine Base ◽  
Base Machine

The article presents theoretical and experimental studies for choosing a manipulator for a harvester taking into account of natural and technological aspects of sustainable development of the forest complex. A mathematical model of the harvester operation is developed based on natural and technological factors, as well as the characteristics of the machine base and the harvester head. Experimental results allow us to determine the rational characteristics of the manipulator for Siberia region of Russia, in particular, the permissible overturn and load moments of the manipulator for the specified characteristics of the base machine and the selected harvesting head. The maximum outreach of the manipulator’s boom in the range from 8000 to 11000 mm has little effect on the volume and number of harvested trees. The percentage of harvested wood volume almost does not depend on the maximum manipulator boom outreach and remains within at least 85%.

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 Maturation of the Na,K-ATPase in the Endoplasmic Reticulum in Health and Disease

2021 ◽  
Author(s):  
Vitalii Kryvenko ◽  
Olga Vagin ◽  
Laura A. Dada ◽  
Jacob I. Sznajder ◽  
István Vadász
Keyword(s):  
Endoplasmic Reticulum ◽  
Intracellular Signaling ◽  
Loss Of Function ◽  
Α Subunit ◽  
Rate Limiting Step ◽  
Atpase Subunits ◽  
A Cell ◽  
Health And Disease ◽  
And Function ◽  
Rate Limiting

Abstract The Na,K-ATPase establishes the electrochemical gradient of cells by driving an active exchange of Na+ and K+ ions while consuming ATP. The minimal functional transporter consists of a catalytic α-subunit and a β-subunit with chaperon activity. The Na,K-ATPase also functions as a cell adhesion molecule and participates in various intracellular signaling pathways. The maturation and trafficking of the Na,K-ATPase include co- and post-translational processing of the enzyme in the endoplasmic reticulum (ER) and the Golgi apparatus and subsequent delivery to the plasma membrane (PM). The ER folding of the enzyme is considered as the rate-limiting step in the membrane delivery of the protein. It has been demonstrated that only assembled Na,K-ATPase α:β-complexes may exit the organelle, whereas unassembled, misfolded or unfolded subunits are retained in the ER and are subsequently degraded. Loss of function of the Na,K-ATPase has been associated with lung, heart, kidney and neurological disorders. Recently, it has been shown that ER dysfunction, in particular, alterations in the homeostasis of the organelle, as well as impaired ER-resident chaperone activity may impede folding of Na,K-ATPase subunits, thus decreasing the abundance and function of the enzyme at the PM. Here, we summarize our current understanding on maturation and subsequent processing of the Na,K-ATPase in the ER under physiological and pathophysiological conditions. Graphic Abstract

Structural Response and Remaining Life of Damaged Composites

2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman
Keyword(s):  
Hybrid Approach ◽  
Experimental Studies ◽  
Structural Response ◽  
Material Behavior ◽  
Experimental Results ◽  
Life Assessment ◽  
Nonlinear Material ◽  
Remaining Life ◽  
Design Effectiveness ◽  
Remaining Life Assessment

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.

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