scholarly journals A New Model for Thermodynamic Characterization of Hemoglobin

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 135 ◽  
Author(s):  
Francesco Farsaci ◽  
Ester Tellone ◽  
Antonio Galtieri ◽  
Silvana Ficarra

In this paper, we formulate a thermodynamic model of hemoglobin that describes, by a physical point of view, phenomena favoring the binding of oxygen to the protein. Our study is based on theoretical methods extrapolated by experimental data. After some remarks on the non-equilibrium thermodynamic theory with internal variables, some thermodynamic functions are determined by the value of the complex dielectric constant. In previous papers, we determined the explicit expression of a dielectric constant as a function of a complex dielectric modulus and frequency. The knowledge of these functions allows a new characterization of the material and leads to the study of new phenomena that has yet to be studied. In detail, we introduce the concept of “hemoglobe”, a model that considers the hemoglobin molecule as a plane capacitor, the dielectric of which is almost entirely constituted by the quaternary structure of the protein. This model is suggested by considering a phenomenological coefficient of the non-equilibrium thermodynamic theory related to the displacement polarization current. The comparison of the capacity determined by the mean of this coefficient, and determined by geometrical considerations, gives similar results; although more thermodynamic information is derived by the capacity determined considering the aforementioned coefficient. This was applied to the normal human hemoglobin, homozygous sickle hemoglobin, and sickle cell hemoglobin C disease. Moreover, the energy of the capacitor of the three hemoglobin was determined. Through the identification of displacement currents, the introduction of this model presents new perspectives and helps to explain hemoglobin functionality through a physical point of view.

2020 ◽  
Vol 46 (2) ◽  
pp. 121-137
Author(s):  
Francesco Farsaci ◽  
Ester Tellone ◽  
Annamaria Russo ◽  
Antonio Galtieri ◽  
Silvana Ficarra

Abstract The importance of studying storage alterations in erythrocytes is highlighted by the need to understand changes that could potentially serve to optimize the storage system. With this aim, the non-equilibrium thermodynamic theory with internal variables was introduced, and perturbing the erythrocyte samples with a harmonic electric field some functions of the theory have been determined varying in the perturbation frequency. A frequency has been noted that acts as a separator element between two states showing a different entropy production above and below this frequency. In stored red blood cells compared to fresh ones, the increase in entropy production measured shows a greater state of disorder in the latter. Further alterations have been highlighted on the surface charge density of the stored erythrocyte membrane and on the speed of anionic kinetics. All these observations highlight the image of membrane structural and functional alterations of the stored erythrocytes and lead to the elaboration of a technique able to correlate a specific perturbation frequency with the aging time of red blood cells.


2009 ◽  
Vol 50 (2) ◽  
pp. 236-244
Author(s):  
Kenichiro Suetsugu ◽  
Atsushi Yamaguchi ◽  
Kazumi Matsushige ◽  
Toshihisa Horiuchi

Soft Matter ◽  
2020 ◽  
Vol 16 (24) ◽  
pp. 5740-5749
Author(s):  
Yu Zhou ◽  
Lihua Jin

A non-equilibrium thermodynamic theory is developed to predict hydrolysis-induced large swelling of polyacrylamide hydrogels.


2015 ◽  
Vol 481 (1) ◽  
pp. 166-188 ◽  
Author(s):  
Shu-Tao Ai ◽  
Hui-Ping Bo ◽  
Shao-Yin Zhang ◽  
Yuan-Zhen Cai

2020 ◽  
Vol 10 (16) ◽  
pp. 5668
Author(s):  
Guangchang Yang ◽  
Yang Liu ◽  
Peipei Chen

A new hydro-mechanical model for unsaturated geotechnical materials based on the non-equilibrium thermodynamic theory is presented in this paper. Common concepts, such as yield criterion and flow rules, are not involved in the constitutive relationships, and are replaced with the thermodynamic concepts of granular temperature, granular entropy, migration coefficients, and energy functions. The dissipation system and the migration coefficient relationships are theoretically determined, and the constitutive relations of non-elastic deformation and granular temperature are obtained by dissipation relations and thermodynamic identity. Thus, the relationship between dissipation mechanism and macro mechanical behavior can be established by migration coefficients and energy functions. The model can reflect the complex hydro-mechanical coupling behavior of unsaturated geotechnical materials subjected to various mechanical paths. The validity of the model is verified by comparing the modeling results with experimental data, and reasonable agreement is achieved.


2007 ◽  
Vol 556-557 ◽  
pp. 13-16 ◽  
Author(s):  
Yeon Suk Jang ◽  
Sakwe Aloysius Sakwe ◽  
Peter J. Wellmann ◽  
Sandrine Juillaguet ◽  
Hervé Peyre ◽  
...  

We have carried out the growth and basic characterization of isotopically enriched 4HSi 13C crystals. In recent years the growth of 13C enriched 6H-SiC has been performed in order to carry out fundamental materials studies (e.g. determination of phonon energies, fundamental bandgap shift, carbon interstitial defect study, analysis of the physical vapor transport (PVT) growth process). For electronic device applications, however, the 4H-SiC polytype is the favored material, because it offers greater electron mobility. In this paper we present the growth of 4H-Si13C single crystals with up to 60% of 13C concentration. From a physical point of view we present first results on phonons as well as the fundamental bandgap energy shift due to 13C incorporation into the SiC lattice.


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