Solution of the Rovibrational Schrödinger Equation of a Molecule Using the Volterra Integral Equation

By using the Rayleigh-Schrödinger perturbation theory the rovibrational wave function is expanded in terms of the series of functions ϕ0,ϕ1,ϕ2,…ϕn, where ϕ0 is the pure vibrational wave function and ϕι are the rotational harmonics. By replacing the Schrödinger differential equation by the Volterra integral equation the two canonical functions α0 and β0 are well defined for a given potential function. These functions allow the determination of (i) the values of the functions ϕι at any points; (ii) the eigenvalues of the eigenvalue equations of the functions ϕ0,ϕ1,ϕ2,…ϕn which are, respectively, the vibrational energy Ev, the rotational constant Bv, and the large order centrifugal distortion constants Dv,Hv,Lv….. Based on these canonical functions and in the Born-Oppenheimer approximation these constants can be obtained with accurate estimates for the low and high excited electronic state and for any values of the vibrational and rotational quantum numbers v and J even near dissociation. As application, the calculations have been done for the potential energy curves: Morse, Lenard Jones, Reidberg-Klein-Rees (RKR), ab initio, Simon-Parr-Finlin, Kratzer, and Dunhum with a variable step for the empirical potentials. A program is available for these calculations free of charge with the corresponding author.

QSAR Study of (5-Nitroheteroaryl-1,3,4-Thiadiazole-2-yl) Piperazinyl Derivatives to Predict New Similar Compounds as Antileishmanial Agents

To search for newer and potent antileishmanial drugs, a series of 36 compounds of 5-(5-nitroheteroaryl-2-yl)-1,3,4-thiadiazole derivatives were subjected to a quantitative structure-activity relationship (QSAR) analysis for studying, interpreting, and predicting activities and designing new compounds using several statistical tools. The multiple linear regression (MLR), nonlinear regression (RNLM), and artificial neural network (ANN) models were developed using 30 molecules having pIC50 ranging from 3.155 to 5.046. The best generated MLR, RNLM, and ANN models show conventional correlation coefficients R of 0.750, 0.782, and 0.967 as well as their leave-one-out cross-validation correlation coefficients RCV of 0.722, 0.744, and 0.720, respectively. The predictive ability of those models was evaluated by the external validation using a test set of 6 molecules with predicted correlation coefficients Rtest of 0.840, 0.850, and 0.802, respectively. The applicability domains of MLR and MNLR transparent models were investigated using William’s plot to detect outliers and outsides compounds. We expect that this study would be of great help in lead optimization for early drug discovery of new similar compounds.

Enhancement of Electrochemical Performance of Bilirubin Oxidase Modified Gas Diffusion Biocathode by Porphyrin Precursor

Recent studies have focused on tailoring the catalytic currents of multicopper oxidase (MCO) enzymes-based biocathodes to enhance oxygen reduction. Biocathodes modified with natural substrates specific for MCO enzymes demonstrated drastic improvement for oxygen reduction. Performance of 1-pyrenebutanoic acid, succinimidyl ester (PBSE), and 2,5-dimethyl-1-phenyl-1H-pyrrole-3-carbaldehyde (Di-Carb) oriented bilirubin oxidase (BOx) modified gas diffusion biocathode has been highly improved by incorporating hematin, a porphyrin precursor as electron transfer enhancement moiety. Hematin modified electrodes demonstrated direct electron transfer reaction of BOx exhibiting larger O2 reduction in current density in phosphate buffer solution (pH 7.0) without the need of a mediator. A remarkable improvement in the catalytic currents with 2.5-fold increase compared to non-hematin modified oriented BOx electrodes was achieved. Moreover, a mediatorless and compartmentless glucose/O2 biofuel cell based on DET-type bioelectrocatalysis via the BOx cathode and the glucose dehydrogenase (GDH) anode demonstrated peak power densities of 1 mW/cm2 at pH 7.0 with 100 mM glucose/10 mM NAD fuel. The maximum current density of 1.6 mA/cm2 and the maximum power density of 0.4 mW/cm2 were achieved at 300 mV with nonmodified BOx cathode, while 3.5 mA/cm2 and 1.1 mW/cm2 of current and power density were achieved with hematin modified cathode. The performance improved 2.4 times which attributes to the hematin acting as a natural precursor and activator for BOx activity enhancement.

Organic Compounds Based on (E)-N-Aryl-2-ethene-sulfonamide as Microtubule Targeted Agents in Prostate Cancer: QSAR Study

(E)-N-Aryl-2-ethene-sulfonamide and its derivatives are potent anticancer agents; these compounds inhibit cancer cells proliferation. A study of quantitative structure-activity relationship (QSAR) has been applied on 40 compounds based on (E)-N-Aryl-2-ethene-sulfonamide, in order to predict their anticancer biological activity. The principal components analysis is used for minimizing the base matrix and the multiple linear regression (MLR) and multiple nonlinear regression have been used to design the relationships between the molecular descriptor and anticancer properties of the sulfonamide derivatives. The validation of the models MLR and MNLR has been done by dividing the dataset into training and test set, the external validation of multiple correlation coefficients was RpIC50 = 0.81 for MLR and RpIC50 = 0.91 for MNLR. The artificial neural network (ANN) showed a correlation coefficient close to 0.96, which concluded that this latter model is more effective and much better than the other models. This obtained model (ANN) has been confirmed by two methods of LOO cross-validation and scrambling (or Y-randomization). The high correlation between experimental and predicted activity values was observed, indicating the validation and the good quality of the derived QSAR model.

Methylene Blue Photocatalytic Degradation under Visible Irradiation on In2S3 Synthesized by Chemical Bath Deposition

In this work, we synthesized In2S3 powder through chemical bath deposition method (CBD) in acid medium; we used thioacetamide as sulphide source and InCl3 as indium ion source. X-ray diffraction, diffuse reflection, and Raman spectroscopy measurements were used for In2S3 powder physicochemical characterization. Optical analysis indicated that In2S3 was active in the visible region of electromagnetic spectrum; it had a band gap of 2.47 eV; the diffraction patterns and Raman spectroscopy suggested that powder had polycrystalline structure. Furthermore, we also studied the adsorption process of methylene blue (MB) on In2S3 powder; adsorption studies indicated that the Langmuir model describes experimental data. Finally, photocatalytic degradation of MB was studied under visible irradiation in aqueous solution; besides, pseudo-first-order model was used to obtain kinetic information about photocatalytic degradation; results indicated that the powder catalyst reduces 26% concentration of MB under visible irradiation.

Synthesis and Characterization of System In(O,OH)S/i-ZnO/n+-ZnO

In this work, we fabricated system In(O,OH)S/i-ZnO/n+-ZnO to be used as potential optical window in thin films solar cells. i-ZnO/n+-ZnO thin films were synthesized by reactive evaporation (RE) method and In(O,OH)S thin films were synthesized by chemical bath deposition (CBD) method; all thin films were deposited on soda lime glass substrates. Thin films were characterized through X-ray diffraction (XRD), atomic force microscopy (AFM), and spectral transmittance measurements. Structural results indicated that both thin films were polycrystalline; furthermore, morphological results indicated that both thin films coated uniformly soda lime glass substrate; besides, optical characterization indicated that system had more than 80% of visible radiation transmittance.

The Effect of Concentration of Lawsonia inermis as a Corrosion Inhibitor for Aluminum Alloy in Seawater

Lawsonia inermis also known as henna was studied as a corrosion inhibitor for aluminum alloy in seawater. The inhibitor has been characterized by optical study via Fourier transform infrared spectroscopy (FTIR). The FTIR proves the existence of hydroxyl and carbonyl functional groups in Lawsonia inermis. Aluminum alloy 5083 immersed in seawater in the absence and presence of Lawsonia inermis was tested using electrochemistry method, namely, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). EIS and PP measurements suggest that the addition of Lawsonia inermis has caused the adsorption of inhibitor on the aluminum surface. The adsorption behavior of the inhibitor follow Langmuir adsorption model where the value of free energy of adsorption, -ΔG, is less than 40 kJ/mol indicates that it is a physical adsorption. Finally, it was inferred that Lawsonia inermis has a real potential to act as a corrosion inhibitor for aluminum alloy in seawater.

Superparamagnetic Iron Oxide (Fe3O4) Nanoparticles Coated with PEG/PEI for Biomedical Applications: A Facile and Scalable Preparation Route Based on the Cathodic Electrochemical Deposition Method

Cathodic electrochemical deposition (CED) is introduced as an efficient and effective method for synthesis and surface coating of superparamagnetic iron oxide nanoparticles (SPIONs). In this way, bare Fe3O4 nanoparticles were electrosynthesized through CED method from aqueous solution Fe3+ : Fe2+ chloride (molar ratio of 2 : 1). In the next step, the surface of NPs was coated with polyethyleneimine (PEI) and polyethylene glycol (PEG) during the CED procedure, and PEG/PEI coated SPIONs were obtained. The prepared NPs were evaluated by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), and field-emission scanning electron microscopy (FE-SEM). The pure magnetite phase and nanosize (about 15 nm) of the prepared NPs were confirmed by XRD and FE-SEM. The presence of two coats (i.e., PEG and PEI) on the surface of electrosynthesized NPs was proved via FTIR results. The percentage of polymer coat (37.5%) on the NPs surface was provided by TGA analysis. The high magnetization value, negligible coercivity, and remanence measured by VSM indicate the superparamagnetic nature of both prepared NPs. The obtained results confirmed that the prepared Fe3O4 nanoparticles have suitable physicochemical and magnetic properties for biomedical applications.

Corrosion Inhibition of Mild Steel in 1 mol L−1 HCl Using Gum Exudates of Azadirachta indica

The ability of gum exudates of Azadirachta indica (GAI) to inhibit corrosion on mild steel in 1 mol L−1 HCl has been studied using mass loss, polarization, and impedence measurements. The effect of temperature (303–323 K) and immersion time of 1, 2, 4, 6, and 12 hours on corrosion behavior of mild steel was examined. Gum exudates decrease the corrosion rate up to a concentration of 80 ppm and at 323 K temperature. GAI adsorb chemically onto the surface of the mild steel while it obeys Langmuir adsorption isotherms. Polarization studies show GAI as mixed mode inhibitor. Surface studies ascertain that a shielding layer was formed on the mild steel surface.

New Homologues Series of Heterocyclic Schiff Base Ester: Synthesis and Characterization

A homologous series of liquid crystal bearing with heterocyclic thiophene Schiff base ester with alkanoyloxy chain (CH3(CH2)nCOO–, where n=4, 6, 8, 10, 12, 14, 16) was successfully synthesized through the modification of some reported methods. The structural information of these compounds was isolated and characterized through some spectroscopic techniques, such as FTIR, 1H, and 13C NMR and elemental analysis. Textural observation was carried out using a polarizing optical microscope (POM) over heating and cooling cycles. It was found that all synthesized compounds (3a–g) exhibited an enantiotropic nematic phase upon the heating and cooling cycle with high thermal stability. Moreover, a characteristic bar transition texture was observed for compounds 3f and 3g which have shown transition of nematic-to-smectic C phase. This has been further confirmed by obtaining relative phase transition temperature using the differential scanning calorimetry (DSC).