Removal of textile pollutants from aqueous medium using biosynthesized CuO nanoparticles: Theoretical comparative investigation via analytical model.

The work deals with the removal of two dyes, namely methylene blue (MB) and methyl orange (MO), from polluted water by adsorption onto CuO nanoparticles synthesized with a green synthesis procedure, starting from plant resources. Adsorption isotherms are determined at different temperatures aiming at investigating the adsorption mechanisms of the two dyes. The experimental results indicate that, for both MB and MO, the adsorption capacity increases with increasing temperature, with slight differences in the case of MO. Comparatively, the CuO nanoparticles show a higher MB adsorption capacity with respect to MO. A modelling analysis is carried out with a multilayer model derived from statistical physics, selected among a group of models, each hypothesizing a different number of adsorbed molecules layers. The analysis of model parameters allows determining that the adsorbate molecules exhibit a non-parallel orientation on the surface of biosynthesized CuO nanoparticles and each functional group of the adsorbent binds multiple molecules, simultaneously.The model also allows determining the number of dye molecule layers formed on adsorbent surface, in all the cases resulting higher than three, also confirming the effect of temperature on the maximum adsorption capacity.Specifically, the total number of dye layers formed on biosynthesized CuO nanoparticles surface exhibited a range of 4.17-4.55 for MB dye and of 3.01-3.51 for MO dye.Finally, the adsorption energies reveal that adsorption likely involves physical forces (all resulting all below 22 kJ/mol), i.e. hydrogen bonding and van der Waals forces. The adsorption energies for the interactions between dye molecules are lower than those calculated for the interactions between the dye molecules and the adsorbent surface.

Investigation of olfactory perception by a putative adsorption process of sotolone and abhexone on human olfactory receptor OR8D1: Statistical physics modeling and molecular docking.

In the present paper, a double layer advanced model was used to investigate the adsorption process putatively involved in the olfactory perception of sotolone and abhexone molecules on the human olfactory receptor OR8D1. The number of adsorbed molecules or the fraction of adsorbed molecule per site, n, informed that the two odorants molecules are docked on OR8D1 binding sites with mixed parallel and nonparallel anchorages. Furthermore, the estimated molar adsorption energy (-ΔE1 and -ΔE2) were inferior to 40 kJ/mol for the two adsorption systems, which confirmed the physical nature and the exothermic character of the adsorption process. In addition, stereographic characterizations of the receptor sites surface were carried out through the determination of the receptor site size distribution (RSDs) via Kelvin equation, which spread out from 0.05 to 1.5 nm. The adsorption energy distributions (AEDs) via Polayni equation show an adsorption band spectrum localized between 17 kJ/mol and 22.5 kJ/mol for sotolone and abhexone molecules respectively. A molecular docking calculation was performed. The results indicate that the binding affinities are belonging to the spectrum of the energy band of the molecules sotolone and abhexone, with values 19.66 kJ/mol and 19.24 kJ/mol.

Quantitative investigations of Zebrafish olfactory receptor ORA1 responsiveness to three pheromones: Microscopic and macroscopic characterizations via an advanced statistical physics treatment.

In this work, an adsorption phenomenon putatively involved in the olfactory sense of phenylacetic acid, 4-chlorophenylacetic acid, and 4-methoxyphenylacetic acid pheromones in the Zebrafish olfactory receptor ORA1 was a helpful mechanism in interpreting and characterizing the olfaction process at a molecular level. Hence, the experimental dose-olfactory response curves were fitted by applying the one-layer adsorption model with a single energy (1LM1E). On one hand, the different parameters introduced in the selected model were used to microscopically study the three olfactory systems. Indeed, the fitting results showed that phenylacetic acid displayed the greatest maximum olfactory response at saturation, due to the effect of functional groups at the R4 position. The three pheromones were docked via a non-parallel orientation and the adsorption process was a multi-molecular mechanism. The sizes of different binding pockets of ORA1 were determined through the estimation of the olfactory receptor site size distributions (stereographic characterization). The estimated adsorption energies, ranging from 17.340 to 21.332 kJ/mol, can be used to describe the energetic interactions between the studied pheromones and the Zebrafish ORA1 binding pockets. The spectrums of the adsorption energy distributions of phenylacetic acid, 4-chlorophenylacetic acid, and 4-methoxyphenylacetic acid, which were spread out from 10 to 32.5 kJ/mol, 5 to 30 kJ/mol, and 10 to 32.5 kJ/mol, respectively, was determined to estimate the corresponding olfactory bands (energetic characterization). On the other hand, three thermodynamic functions were estimated in order to macroscopically study the three olfactory systems.

Modeling by statistical physics and interpretation of the olfactory process of the two enantiomers 3-mercapto-2-methylbutan-1-ol and 3-mercapto-2-methylpentan-1-ol on the OR2M3 human olfactory receptor.

In the present paper, a putative adsorption process of two odorants thiols (3-mercapto-2-methylbutan-1-ol and 3-mercapto-2-methylpentan-1-ol) on the human olfactory receptor OR2M3 has been investigated via advanced models developed by a grand canonical formalism of statistical physics. For the two olfactory systems, a monolayer model with two types of energy (ML2E) has been selected to correlate with the experimental data. The physicochemical analysis of the statistical physics modeling results showed that the adsorption system of the two odorants was multimolecular. Furthermore, the molar adsorption energies were inferior to 22.7 kJ/mol, which confirmed the physisorption process of the adsorption of the two odorant thiols on OR2M3. In addition, quantitative characterizations of both odorants were determined via the olfactory receptor pore size distribution (RPSD) and the adsorption energy distribution (AED), which were spread out from 0.25 to 1.25 nm and from 5 to 35 kJ/mol, respectively. For thermodynamic characterization of the olfactory process, the adsorption entropy indicated the disorder of the adsorption systems of 3-mercapto-2-methylbutan-1-ol and 3-mercapto-2-methylpentan-1-ol on the human olfactory receptor OR2M3. Besides, the used model showed that the presence of copper ions increases the efficacy (olfactory response at saturation) of 3-mercapt-2-methylpentan-1-ol odorant activating OR2M3. The docking molecular simulation indicated that the 3-mercapto-2-methylpentan-1-ol molecule presented more binding affinities (17.15 kJ/mol) with olfactory receptor OR2M3 than 3-mercapto-2-methylbutan-1-ol (14.64 kJ/mol). On the other hand, the two estimated binding affinities of the two odorants belonged to the adsorption energies spectrum (AED) to confirm the physisorption nature of the olfactory adsorption process.

Elimination of aspirin and paracetamol from aqueous media using Fe/N-CNT/ß-cyclodextrin nanocomposite polymers: theoretical comparative survey via advanced physical models.

The main purpose of this research is to theoretically investigate the adsorption of two pharmaceutical molecules, i.e. aspirin and paracetamol, using two composite adsorbents, i.e. N-CNT/ß-CD and Fe/N-CNT/ß-CD nanocomposite polymers. A multilayer model developed by statistical physics is implemented to explain the experimental adsorption isotherms at the molecular scale, so as to overpass some limitations of the classical adsorption models. The modelling results indicate that the adsorption of these molecules is almost accomplished by the formation of 3 to 5 adsorbate layers, depending on the operating temperature. A general survey of the number of adsorbate molecules captured by the adsorption site (npm) suggested that the adsorption process of pharmaceutical pollutants is multimolecular and that each adsorption site can capture several molecules simultaneously. Furthermore, the npm values demonstrated the presence of aggregation phenomena of aspirin and paracetamol molecules during adsorption. The evolution of the adsorbed quantity at saturation confirmed that the presence of Fe in the adsorbent enhanced the removal performance of the investigated pharmaceutical molecules. In addition, the adsorption of the pharmaceutical molecules aspirin and paracetamol on the N-CNT/ß-CD and Fe/N-CNT/ß-CD nanocomposite polymer surface involved weak physical type interactions, since the interaction energies do not overcome the threshold of 25 000 J mol-1.

New insights on the adsorption of floral odorants on Apis cerana cerana olfactory receptor AcerOr1: Theoretical modeling and thermodynamic study.

Apis cerana cerana counted on its sensitive olfactory system to make survival activities in the surrounding environment and the olfactory receptors can be considered as a primary requirement of odorant detection, recognition and coding. Indeed, the exploitation of the olfactory system of insects in particular the Asian honeybee "Apis cerana cerana" can be the best experimental model to investigate the essentials of the chemosensitivity and may help to better understand the olfactory perception in insects. Hence, an advanced statistical physics modeling via the monolayer model with single energy (n ≠ 1) of the three dose-olfactory responses curves indicated that undecanoic acid, 1-octyl alcohol and 1-nonanol were docked with a mixed parallel and non-parallel orientation on AcerOr1. Furthermore, in the present work, the Apis cerana cerana olfactory receptor AcerOr1 showed high sensitivity and discrimination power to detect undecanoic acid, 1-octyl alcohol and 1-nonanol with concentrations at half saturations values of 10-7 mol/L and the molar adsorption energy values obtained from data fitting results, which were ranged from 17.91 to 24.00 kJ/mol, confirmed the exothermic and the physisorption nature of the adsorption of the studied floral odorants on AcerOr1. The studied experimental dose-response curves of undecanoic acid, 1-octyl alcohol and 1-nonanol provided access to quantitative (i.e., stereographic and energetic) characterizations of AcerOr1 via the determination of the olfactory receptor site size distributions (RSDs) and the adsorption energy distributions (AEDs). The stereographic characterization showed RSDs spread out from 0.20 to 8 nm presenting average values corresponding to the maximum of the peaks at 1.50 nm, at 1.10 nm and at 1.04 nm for undecanoic acid, 1-octyl alcohol and 1-nonanol, respectively. The energetic characterization presented AEDs ranged from 0 to 40 kJ/mol showing an approximate adsorption energy bands defined between 7.50 and 27.50 kJ/mol, between 15 and 33 kJ/mol and between 13.50 and 34.50 kJ/mol for undecanoic acid, 1-octyl alcohol and 1-nonanol, respectively. The utilization of the analytical expression of the olfactory threshold allowed giving important and helpful informations about the occupation rate of AcerOr1 binding sites that fired a minimal olfactory response at a honeybee olfactory receptor. Hence, the olfactory response can be detected only when 1.97 %, 1.13 % and 2.00 % of AcerOr1 binding sites were occupied by undecanoic acid, 1-octyl alcohol and 1-nonanol, respectively. Lastly, by means of the selected model, the thermodynamic potentials, such as the adsorption entropy, the Gibbs free enthalpy and the internal energy could be calculated and interpreted.

Quantitative characterizations of mOR-EG activated by vanilla odorants using advanced statistical physics modeling.

An advanced monolayer adsorption model of an ideal gas was successfully employed to investigate the adsorption of vanillin, vanillin methyl ether, vanillin ethyl ether, and vanillin acetate odorants on mouse eugenol olfactory receptor mOR-EG. In order to understand the adsorption process putatively introduced in olfactory perception, model parameters were analyzed. Hence, fitting results showed that the studied vanilla odorants were linked in mOR-EG binding pockets with a non-parallel orientation, and their adsorption was a multi-molecular process (n > 1). The adsorption energy values that ranged from 14.021 to 19.193 kJ/mol suggested that the four vanilla odorants were physisorbed on mOR-EG (ΔEa < 40 kJ/mol) and the adsorption mechanism may be considered as an exothermic mechanism (ΔEa > 0). The estimated parameters may also be utilized for the quantitative characterization of the interactions of the studied odorants with mOR-EG to determine the corresponding olfactory bands ranging from 8 to 24.5 kJ/mol.

Advanced investigation of a putative adsorption process of nine non key food odorants (non-KFOs) on the broadly tuned human olfactory receptor OR2W1: Statistical physics modeling and molecular docking study.

In the present paper, statistical physics formalism was used to understand the olfactory perception via the investigation of dose-olfactory response curves of a putative adsorption process of nine non key food odorants (non-KFOs) on the broadly tuned human olfactory receptor OR2W1, in order to quantitative characterize the interactions between the nine studied non-KFOs, i. e., furfuryl sulfide, furfuryl disulfide, benzyl methyl disulfide, furfuryl methyl disulfide, benzyl methyl sulfide, 1-phenylethanethiol, benzyl mercaptan, furfuryl methyl sulfide and 3-phenylpropanol molecules and OR2W1 binding sites at a molecular level. Two advanced adsorption models have been proposed: the advanced monolayer monoenergy model (monolayer model with identical and independent olfactory receptor binding sites) (Model 1) and the advanced monolayer model with two independent types of olfactory receptor binding sites (Model 2). It was concluded that the monolayer monoenergy model was selected as the most adequate model to fit the experimental dose-olfactory response curves tabulated in literature. Actually, the numerical values of the three fitted physico-chemical parameters (RM1, n and C1) were obtained by a non-linear regression. Indeed, modeling results suggested that the number of docked non-KFOs per OR2W1 binding site n values (1.24 < n < 1.94) was always superior to 1, which indicated the non-parallel orientation of the studied odorants on the olfactory receptor and the multi-molecular adsorption mechanism. The estimated molar adsorption energy ΔEa values (ranged from 6.07 to 12.16 kJ/mol) for the nine olfactory systems confirmed the physical the exothermic characters of the adsorption process since ΔEa values were lower than 40 kJ/mol and positive. Furthermore, these estimated parameters were applied to characterize stereographically and energetically the interaction between the nine non-KFOs and OR2W1 through the determination of the human receptor binding site size distributions (RSDs) and the adsorption energy distributions (AEDs), which were spread out from 0.25 to 6.50 nm and from 0 to 22.50 kJ/mol, respectively. The docking computation between these nine non-KFOs and OR2W1 proved that the estimated binding affinities were belonged to the adsorption energies spectrum in general and the specific adsorption energy band or the molecular vibration modes limited spectrum (between 2.50 kJ/mol and 17 kJ/mol) (approximate olfactory band).

Advanced investigation of the olfactory perception of semiochemical TMT on OR5K1 and Olfr175 by statistical physics approach.

The adsorption of the trimethylthiazoline (TMT) on the human olfactory receptor OR5K1 and the mouse olfactory receptor Olfr175 was the object of the present paper. The main contribution of this work was to characterize stereographically and energetically OR5K1 and Olfr175 activated by trimethylthiazoline molecules docked on the human and the mouse olfactory binding pockets using the grand canonical ensemble in statistical physics. The experimental data and the advanced statistical physics models revealed that the adsorption of the trimethylthiazoline on the human olfactory receptor OR5K1 can be interpreted using the monolayer model with single energy, while the monolayer model with two energies described the interaction between the trimethylthiazoline molecules and the mouse olfactory receptor Olfr175. In fact, the investigated odorant was shown to be docked by a multi-docking process and non parallel orientation on OR5K1 and Olfr175 since the values of the number of TMT molecules per binding site n were superior to 1. The proposed models were applied to calculate the human and the mouse olfactory receptor binding site size distributions relative to TMT, which were spread out from 0.30 to 20 nm with a maximum at about 1.75 nm for OR5K1 and from 1 to 25 nm with a peak at about 4.25 nm for Olfr175. Furthermore, it was found from the calculated molar adsorption energies, which were lower than 11 kJ/mol, that physical adsorption process was occurred in the two olfactory systems. The adsorption energy distributions relative to TMT can be also calculated in order to understand of olfaction process in general through the determination of olfactory bands (i. e., adsorption energy distribution bands), which were situated between 0 and 10.50 kJ/mol and between 3 and 12.50 kJ/mol for OR5K1 and Olfr175, respectively. Referring to the investigation of thermodynamic functions governing the adsorption process such as the adsorption entropy, the Gibbs free enthalpy and the internal energy, it may be noted that the disorder peak of the two olfactory systems was reached when the equilibrium concentration was equal to the concentration at half saturation. In addition, the Gibbs free enthalpy and the internal energy were calculated and their negative values indicated that the adsorption process involved in the olfactory mechanism was exothermic and spontaneous nature.

Indirect characterizations of mOR-EG: Modeling analysis of five concentration-olfactory response curves via an advanced monolayer adsorption model.

The investigation of the adsorption process putatively involved in the olfactory perception of apocynin, guaiacylacetone, homovanillyl alcohol, 4-ethylguaiacol and homoguaiacol molecules on the mouse eugenol olfactory receptor mOR-EG was a very useful tool for comprising olfaction process at a molecular level. Indeed, the experimental data were correlated by using an advanced monolayer adsorption model with identical and independent binding sites. Thanks to the grand canonical ensemble in statistical physics formalism, the physico-chemical interpretations of modeling results indicated that the five odorants were adsorbed via a multi-molecular mechanism. Hence, the calculation of adsorption energies, that described the interaction between the odorant molecules and the olfactory receptor binding cavities, indicated that weak bonds were made between apocynin, guaiacylacetone, homovanillyl alcohol, 4-ethylguaiacol and homoguaiacol molecules and mOR-EG binding pockets amino acid residues. In addition, theoretical stereographic and energetic characterizations of mOR-EG were made via the determination of the olfactory receptor site size distributions (RSDs) and the adsorption energy distributions (AEDs) relative to apocynin, guaiacylacetone, homovanillyl alcohol, 4-ethylguaiacol, homoguaiacol molecules. The RSD provided the size of different binding cavities of mOR-EG. Indeed, the five RSDs spectrums situated between 0.5 and 10 nm were spread out around an average size each one. The mean values obtained from the peaks of the distributions were 2.14 nm, 2.20 nm, 2 nm, 2.10 nm and 1.83 nm for apocynin, guaiacylacetone, homovanillyl alcohol, 4-ethylguaiacol and homoguaiacol molecules, respectively. The AED gave a whole spectrum of adsorption energies that was activated by the odorant molecule. Thus, the apocynin, guaiacylacetone, homovanillyl alcohol, 4-ethylguaiacol and homoguaiacol AEDs were spread out from 5 to 27.5 kJ/mol, from 5 to 30 kJ/mol, from 5 to 35 kJ/mol, from 0 to 22.5 kJ/mol, 5 to 25 kJ/mol, respectively. The thermodynamic study, via the establishment of the adsorption entropy, indicated that the peak of the disorder was obtained when half of the binding sites were occupied. In addition, the Gibbs free enthalpy and the internal energy were determined and their negative values indicated that the adsorption phenomenon involved in the olfactory perception was spontaneous and exothermic physisorption phenomenon.

Theoretical study of the olfactory perception of floral odorant on OR10J5 and Olfr16 using the grand canonical ensemble in statistical physics approach.

In this work, two experimental dose-response curves of lyral molecules on the OR10J5 and the Olfr16 were employed in order to examine the evolution of physico-chemical parameters involved in the selected statistical physics model(s) to investigate the human and the mouse smelling of a floral scent. Indeed, one layer adsorption model on one type of sites with one energy (1LAM1T1E) and one layer adsorption model on two types of sites with two energies (1LAM2T2E), considered as appropriate models for the adsorption of lyral molecules on the OR10J5 and Olfr16, respectively, have been applied to fit the experimental data. Stereographic and energetic physico-chemical parameters, namely: the maximum response(s) at saturation, the number of docked molecules per olfactory receptor binding site and the concentration(s) at half saturation, were investigated to retrieve helpful information to describe the adsorption process putatively introduced in the olfaction perception. Thus, the advanced modeling results indicated that the studied molecules were docked with a non-parallel orientation (n > 1). Furthermore, for the two olfactory systems, the molar adsorption energies estimated from curves modeling were inferior to 11 kJ/mol, which showed the physisorption process of the adsorption of lyral molecules on OR10J5 and Olfr16. The 1LAM2T2E and the 1LAM1T1E were applied to estimate the OR10J5 and the Olfr175 RSDs, respectively. Hence, lyral RSDs were spread out from 0.7 to 20 nm with maximums at about 4 nm for OR10J5 and at about 3.65 nm for Olfr16. In addition, by using the two advanced models, the olfactory responses of lyral on OR10J5 and Olfr16 can be used for the energetic characterization of the lyral-OR10J5/Olfr16 binding sites interactions and allowed access to the adsorption energy distributions (AEDs). Then, two approximate olfactory bands can be determined for lyral molecules docked on OR10J5 and Olfr16, which are defined between 3 and 15.5 kJ/mol and between 3.5 and 13.5 kJ/mol, respectively. Lastly, thanks to the proposed models the adsorption entropy of the studied systems can be calculated to describe the disorder and the order on OR10J5 and Olfr16 surfaces (disorder peak of the two olfactory systems was attained when the equilibrium concentration was equal to the concentration at half saturation). Furthermore, the Gibbs free enthalpy and the internal energy were estimated and their negative values indicated that the adsorption phenomenon involved in the olfactory perception was spontaneous and exothermic nature.

Physico-chemical investigations of human olfactory receptors OR10G4 and OR2B11 activated by vanillin, ethyl vanillin, coumarin and quinoline molecules using statistical physics method.

This research work is a contribution to understand the olfaction mechanism at a molecular level of vanillin, ethyl vanillin, coumarin and quinoline molecules using a modeling of a putative adsorption process by analytical model established by statistical physics formalism. A statistical physics modeling using the monolayer model with identical and independent binding sites of the responses of the two human olfactory receptors OR10G4 and OR2B11 showed that vanillin and quinoline were adsorbed with a mixed non-parallel and parallel orientation on OR10G4 and on OR2B11, respectively. However, ethyl vanillin and coumarin were anchored with a total non-parallel orientation. The adsorption energy values collected from data analysis, which were ranged from 12.51 to 20.91 kJ/mol, confirmed that the adsorption of vanillin and ethyl vanillin on OR10G4 and the adsorption of coumarin and quinoline on OR2B11were exothermic and were based on physical interactions. Furthermore, the dose-olfactory response curves of vanillin, ethyl vanillin, coumarin and quinoline provided access to OR10G4 and OR2B11 steric characterization via the calculation of the studied olfactory receptors site size distributions (RSDs). Indeed, vanillin, ethyl vanillin, coumarin and quinoline RSDs are spread from 0.3 to 12 nm, from 0.5 to 12 nm, from 0.40 to 12 nm and from 0.14 to 12 nm, respectively, with a maximum at 1.55 nm, 2.11 nm, 2.50 and 1.13 nm, respectively. Lastly, the physico-chemical model parameters can be used for the energetic characterization to confirm the physical nature of the vanillin/ethyl vanillin-OR10G4 and the coumarin/quinoline-OR2B11 interactions and to determine an olfactory band of order of 12 kJ/mol [11-23 kJ/mol], 10 kJ/mol [14-24 kJ/mol], 7 kJ/mol [9-16 kJ/mol], 15 kJ/mol [13-28 kJ/mol] for vanillin, ethyl vanillin, coumarin and quinoline, respectively, through the determination of the adsorption energy distributions (AEDs).

Steric and energetic characterizations of mouse and human musk receptors activated by nitro musk smelling compounds at molecular level: Statistical physics treatment and molecular docking analysis.

Understanding olfaction process at a microscopic or molecular level needs more elucidation of the multiple stages involved in the olfaction mechanism. A worth full elucidation and a better understanding of this molecular mechanism, a necessary preamble should be achieved. The content of this work is a preamble for that. A study of the mouse and human olfactory receptors activation in response to two nitro musks stimuli, which are the musk xylol and the musk ketone, are considered here, first, for their wide expanded use in perfumery, but also to show some particular aspects of this process in the case of these two stimuli, which could help to deduce more details and more general aspects in the global olfactory mechanism. A statistical physics modeling using the monolayer model with two independent types of receptor binding sites of the response of the mouse olfactory receptor MOR215-1 and the human olfactory receptor OR5AN1, which are identified as specifically responding to musk compounds, is used to characterize the interaction between the two nitro musk molecules, the mouse and the human olfactory receptors and to determine the olfactory band of these two odorants through the determination of the molar adsorption energies and the adsorption energy distributions. The physico-chemical model parameters can be used for the steric characterization via the calculation of the receptor site size distributions. The docking computation between these two nitro musks and the human olfactory receptor OR5AN1 is performed demonstrating a large similarity in receptor-ligand detection process. Thus, docking finding results prove that the calculated binding affinities were belonging to the spectrum of adsorption energies.

Statistical physics modeling and interpretation of the adsorption of enantiomeric terpenes onto the human olfactory receptor OR1A1.

The statistical physics approach has been well studied by our research team for liquid and gaseous adsorption systems. This treatment is based on the grand canonical partition function to give new interpretations of the adsorption process at molecular level for chemical senses: olfaction and taste. This work represents a contribution to understand the olfaction mechanism of four of enantiomeric terpenes by applying a statistical physics treatment that allows giving a physico-chemical meaning to parameters involved in the analytical model. It is possible to estimate the number of adsorbed molecules per site, the anchorage number, the receptor density, the concentration at half saturation and the molar adsorption energy. Through this selection of the best fitting model and through fitted values of these parameters, we showed that the adsorption of carvone and limonene enantiomers is not a multilayer process but a monolayer monosite process (monolayer adsorption model with identical and independent sites (n ≠ 1)). The physico-chemical model parameters can be used for the energetic characterization of the interactions between the carvone and the limonene enantiomers and the human olfactory receptor OR1A1 and the determination of an olfactory band of order of 14 kJ/mol, 7 kJ/mol, 9 kJ/mol, 8 kJ/mol for (R)-(-)-carvone, (S)-(+)-carvone, (R)-(+)-limonene and (S)-(-)-limonene, respectively, through the determination of the adsorption energy values and the adsorption energy distributions (AEDs). Thanks to the grand canonical formalism in statistical physics, the negative values of the Gibbs free enthalpy indicate that the adsorption process of the four enantiomeric terpenes onto the human olfactory receptor OR1A1 was spontaneous. The exothermic adsorption mechanism involved in the olfactory perception was explained via the negative values of the internal energy.

Absorption and desorption of hydrogen in Ti1.02Cr1.1Mn0.3Fe0.6RE0.03: experiments, characterization and analytical interpretation using statistical physics treatment.

In this work, the absorption and desorption isotherms of hydrogen on Ti1.02Cr1.1Mn0.3Fe0.6RE0.03 (RE = La, Ce, Ho) metals were collected at three temperatures under the same experimental conditions. This was carried out in order to determine the rare earth effect on the hydrogen storage performance of the Ti1.02Cr1.1Mn0.3Fe0.6 metal. The equilibrium data showing the hydrogen absorbed/released amounts per unit of absorbent mass have provided useful details to describe the absorption/desorption processes. Indeed, statistical physics formalism is appealing to ascribe advanced interpretations to the complexation mechanism. The physico-chemical parameters included in the model analytical expression are numerically determined from the experimental data fitting. We have found that the model can describe the complexation process through steric parameters such as the site densities (N 1m and N 2m), the numbers of atoms per site (n 1 and n 2) and energetic parameters (P 1 and P 2). The behavior of each parameter is examined in relation to the sorption mechanism. Overall, the energetic interpretation reveals that the desorption and absorption of H-gas in the Ti1.02Cr1.1Mn0.3Fe0.6RE0.03 alloys can be characterized by chemical interactions. In addition, the expression of the appropriate model is exploited to determine the thermodynamic potential functions that describe the absorption phenomenon.

Modeling the removal of Reactive Red 120 dye from aqueous effluents by activated carbon.

The adsorption isotherms of Reactive Red 120 (RR-120) on Brazilian pine-fruit shell activated carbon, at six temperatures (298, 303, 308, 313, 318 and 323 K) and pH = 6, were determined and interpreted using a double layer model with one energy. A statistical physics treatment established the formulation of this model. Steric and energetic parameters related to the adsorption process, such as the number of adsorbed molecules per site, the receptor sites density and the concentration at half-saturation, have been considered. Thermodynamic potential functions such as entropy, internal energy and Gibbs free enthalpy are analyzed, and the choice of the models is based on assumptions in correlation with experimental conditions. By numerical fitting, the investigated parameters were deduced. The theoretical expressions provide a good understanding and interpretation of the adsorption isotherms at the microscopic level. We believe that our work contributes to new theoretical insights on the dye adsorption in order to know the physical nature of the adsorption process.

Investigation of mouse eugenol olfactory receptor activated by eugenol, vanillin and ethyl vanillin: Steric and energetic characterizations.

Steric and energetic characterizations were performed for the adsorption of eugenol (EG), vanillin and ethyl vanillin (EV) onto the mouse eugenol olfactory receptor mOR-EG by using a proposed model expression established by statistical physics methods. We started with a modeling of dose-response curves. The calculated curves fit well the experimental data and the physico-chemical model parameters can be used for the characterization of the interactions between the eugenol, vanillin and ethyl vanillin molecules and the mouse eugenol receptor and the determination of the olfactory band for these three odorant molecules through the determination of the adsorption energy values and the adsorption energy distributions. Furthermore, thermodynamic functions of the odorant adsorption such as the configurational entropy, Gibbs free enthalpy and internal energy were calculated and their negative values indicate that the adsorption process included in the olfaction mechanism was exothermic and spontaneous nature.

A microscopic and macroscopic investigation of the adsorption of N719 dye on ZnO nanopowders (ZNP) and ZnO nanorods (ZNR) for dye sensitized solar cells using statistical physics treatment and DFT simulation.

In this paper, three adsorption isotherms of N719 dye on two different adsorbents, ZnO nanopowder and ZnO nanorods, at three different thicknesses have been fitted using a monolayer model with three types of receptor sites treated by statistical physics. The model involved parameters are: three coefficients (n 1, n 2 and n 3) indicating the numbers of adsorbed dye molecules per site, three parameters (N m1, N m2 and N m3) indicating the receptor site densities and three adsorption energies ((-ε 1), (-ε 2) and (-ε 3)). The evolution of these parameters in relation with thickness of ZnO was discussed. The pore size distribution (PSD) of ZnO nanopowder and ZnO nanorods as a function of the thickness has been studied using the chosen adequate model. The molecular electrostatic potential (MEP) has been investigated to optimize the different adsorbed geometries of the complex N719 dye@ZnO. The intermolecular interactions between the N719 dye and the ZnO surface have been studied by using the quantum theory of atoms in molecules (AIM) and reduced density gradient RDG. The results of the MEP, topological AIM and RDG are in agreement with the results of statistical physics.

Investigation of caffeine taste mechanism through a statistical physics modeling of caffeine dose-taste response curve by a biological putative caffeine adsorption process in electrophysiological response.

This work is a contribution to understand the taste mechanism of caffeine molecule using a modeling of a putative adsorption process by model expressions established by a statistical physics treatment. A physicochemical and a gustative parts are the main constituents of this work. We start with a physicochemical investigation of the adsorption process of caffeine molecule, as adsorbate in liquid phase, onto ß-cyclodextrin as adsorbent. Experimental adsorption isotherm curves of caffeine onto ß-cyclodextrin coated onto Quartz crystal are carried out at three different temperatures. The Hill model expression with three parameters n, NM and C1/2, established by statistical physics formalism investigated in part I, is the best fitting model of the experimental data. Thermodynamic potential functions that govern the adsorption process, such as entropy, internal energy and Gibbs free enthalpy are investigated. PSD and AED are derived by a steric and energetic derivatives of the Hill model. In part II the same method of fitting is applied to the taste electrophysiological dose-response curve by a caffeine putative adsorption on gustative nerve in caterpillar. All the physicochemical parameters introduced in the fitting Hill model expression, serve first, to analyze the taste mechanism of the bitter caffeine taste. Secondly, all these stereographic and energetic parameters will be considered henceforward for an objective characterization of caffeine molecule taste in both its two aspects, intensive and qualitative aspects of caffeine taste.