Showing papers by "Roya Ahmadi published in 2019"

Adsorption of melphalan anticancer drug on the surface of fullerene (C24): a comprehensive DFT study

Abstract: Objective (s): The present study aimed to assess the adsorption of fullerene C24 with Melphalan anticancer agent in a solvent phase (water) at the B3LYP/6-31G (d) theoretical level.Materials and Methods: Initially, the structures of Melphalan and fullerene complexes were optimized in four configurations. Afterwards, IR calculations and molecular orbital analysis were performed. In addition, some important parameters were assessed, including the adsorption energy, Gibbs free energy changes (ΔGad), enthalpy (ΔHad) variations, thermodynamic equilibrium constant, specific heat capacity, chemical hardness, energy gap, and electrophilicity. Results: According to the results, Gibbs free energy changes (ΔGad), enthalpy (ΔHad) variations, III-Isomer, and IV-Isomer were negatives at various temperatures, while for I-Isomer and II-Isomer were positives throughout the temperature range of 298.15-310.15 K.Conclusion: Since according to the obtained results for adsorption of Melphalan on the C24 in , III-Isomer, and IV-Isomer were spontaneous at various temperatures, while I-Isomer and II-Isomer were not spontaneous throughout the temperature range of 298.15-310.15 K.Conclusion: Since the adsorption of Melphalan with fullerene C24 is spontaneous. Moreover, the effects of temperature on thermodynamic parameters were investigated, and the calculated specific heat capacity values indicated that C24 could be utilized as a sensing material in the construction of thermal biosensors for Melphalan determination.

Investigating the Influence of Doping Graphene with Silicon and Germanium on the Adsorption of Silver (I)

Abstract: In this study, the impact of doping graphene with silicon and germanium on the adsorption of Ag+ was evaluated by density functional theory. At the outset, the structures of silver, adsorbents and their derived products at ten different configurations were optimized geometrically. Then, IR and frontier molecular orbital calculations were implemented on them and some important parameters such as adsorption energy, Gibbs free energy changes, enthalpy variations, the thermodynamic equilibrium constant, specific heat capacity, chemical hardness, energy gap and electrophilicity were obtained and inspected. The achieved results indicate that by doping graphene with silicon and germanium the adsorption process has become more spontaneous, exothermic and experimentally feasible. The influence of temperature on the adsorption procedure was also checked out and the results indicate that 298.15 K is the optimum temperature for the desired process at all of the evaluated configurations. The HOMO-LUMO related parameters reveal that the pure and also doped nano-adsorbents are not appropriate sensing material in the construction of conductometric sensors but they can act as an eminent neutral ion carrier in the development of a potentiometric ion selective electrode for determination of silver (I) cations.

Effect of nonsurgical periodontal therapy on the level of salivary antioxidants in patients with generalized moderate-to-severe chronic periodontitis

Abstract: Background. In the course of periodontal diseases, polymorphonuclear leukocytes (PMNs) produce oxidative agents and free radicals, thus triggering oxidant-antioxidant disequilibrium in the saliva. Due to the reduction of antioxidant protective effect, oxidative stress is induced, destroying periodontal tissues. This study aimed to investigate the consequences of the non-surgical phase of periodontal therapy on the level ofsalivary antioxidantsin patients with generalized moderate-to-severe chronic periodontitis. Methods. Un-stimulated salivary samples were collected from 43 patients with generalized moderate-to-severe chronic periodontitis for 5 minutes. Clinical parameters, including clinical attachment loss (CAL), bleeding on probing (BoP) and pocket depth (PD), were recorded in each tooth and subsequently, scaling and root planing (SRP) was carried out. After four weeks, salivary samples were collected once again, and the above-mentioned clinical parameters were recorded. Following centrifugation and freezing at a temperature of -80°C, salivary samples were examined simultaneously in a single day, and the level of their antioxidants was measured with ferric reducing ability of plasma (FRAP) method using a spectrophotometer. Results. The concentration of salivary antioxidants significantly increased four weeks following the non-surgical periodontal therapy (P<0.0001). Moreover, the clinical parameters of CAL, BoP and PD showed a significant decrease in 4 weeks as well (P<0.0001). Conclusion. The level of salivary antioxidants in patients with generalized moderate to severe chronic periodontitis significantly increased after etiotropic periodontal therapy, indicating the possible beneficial influence of periodontal therapy on the level of salivary antioxidants in patients suffering from periodontitis.

Effect of B12N12 junction on the energetic and chemical features of PATO: A density functional theory investigation

Abstract: In this study, the reaction of 3-Picrylamino-1, 2, 4-Triazole (PATO) with B12N12 was investigated by density functional theory in the B3LYP/6-31G(d) level of theory. There were two possible isomers for reaction of PATO with B12N12 via carbon and nitrogen atoms of triazole ring to the Born atom of B12N12 (I and II-isomers). Thermodynamic parameters of these reactions including formation Enthalpy changes (ΔHf), Gibbs free energy alterations (ΔGf) and Heat capacity (Cv) were calculated in the temperature range of 300-400K. Variations of density and dipole moment values of PATO after interaction were studied. Also, the frontier orbital energies, HOMO-LUMO gap, chemical hardness (η), electrophilicity index (ω), charge transferred (∆Nmax) and chemical potential (μ) were computed.