نشریه شیمی کاربردی روز
پیاپی 21 (زمستان 1390)

In this work, adsorption of O on Ni(111) surface with p(2×2) configuration and coverage value of 0.25 ML is investigated using Density Functional Theory (DFT). First, using structural optimization gives 1.87 Ǻ and 1.17 Ǻ, respectively for Ni-O bond length and distance of O from the surface. In order to obtain harmonic and anharmonic frequencies of adsorptive bond, distance of O from the surface was statically changed around its minimum value and energy differences are fitted by harmonic and Morse potential models. The results for frequency calculations are in good agreement with experimental data. Also, the Fermi energy of Ni surface is increased by O adsorption which exhibits the charge transfer from O to surface. However, the large electron negativity of O atom reduces its partial positive charge which leads to decrease of mechanical anharmonicity.

Biocompatible and biodegradable pH-responsive hydrogels based on acrylic acid and acrylamide onto chitosan were prepared for controlled drug delivery of the drug acyclovir (ACV), which can be used for treatment of Herpes simplex and Varicella Zoster. These interpolymeric hydrogels were synthesized by a free radical polymerization technique using ammonium persulfate (APS) as initiator and methylene bisacrylamide (MBA) as a crosslinker.The synthesized hydrogels were subjected to equilibrium swelling studies in simulated gastric and intestinal fluids (SGF and SIF). Hydrogels containing drug ACV, at different drug-to-polymer ratios, were prepared by direct adsorption method. The loading yield was found to depend on both the impregnation time and the amount of encapsulated drug. In vitro drug-release studies in different buffer solutions showed that the most important parameter affecting the drug-release behavior of hydrogels is the pH of the solution. More than 50% of the entrapped drugs were released in the first 2h at gastric pH and the rest of the drug release was slower.

Quantitative structure-activity relationship (QSAR) study for prediction of medicinal activity of pyrazole derivatives is developed using structural descriptors and multiple linear regression (MLR) method. Molecular descriptors are selected by genetic algorithm. Then a simple, strong, descriptive and interpretable model with low error and high correlation coefficient is construct. The results illustrated that the linear techniques such as MLR combined with a successful variable selection procedure are capable to generate an efficient QSAR model for predicting the activity of different compounds. This model was used for the prediction of activity values of some medicinal compounds which were not used in the modeling procedure.

Areas where the soil and groundwater containing large quantities of sulfate and where structures are built in marine environments, must be designed of a kind of concrete that have sufficient resistance about sulfate attacks. Sulfate salts in the solid state are unable to harm the concrete, but when they are in the solution state, can reaction with materials created from the operation of the Cement Hydration i.e. calcium hydroxide, calcium aluminate and silicate hydrate, that these reactions lead to the failure and collapse of concrete. In this study, extraction rate and optimal conditions for utilization of sodium sulfate in Urmia lake water using minimal energy and climate zone and using non-evaporating method has been investigated. Due to the high amounts of sodium sulfate deposits in Iran and also the lack of chemical reaction in the process of processing, consequently easy equipments, tips and technical operating conditions studied in this case is very important. In addition, economic investment was performed on the extraction of sodium sulfate and a plan to create semi-industrial and industrial units for the extraction of sodium sulfate with the lowest energy and money spent has been proposed. Due to abundant amounts of sulfate ion in Urmia lake water, concrete structures of causeway bridge on Shahid Kalantari Highway between Urmia and Tabriz are not safe from corrosion damage resulting from sulfate. In this scheme corrosion causes by sulfate ion and Results of the study was obtained.

The essential oil of Fumaria Vaillantii Loisel was isolated by hydrodistillation using a Clevenger-type apparatus. In order to, identification of chemical composition, the obtained essential oil was injected to GC/MS instrument. Thirty six components were identified, the major components more than 1 percent include: trans anethole (14.97%), 1,8-cineole (13.01%), menthole (9.34 %), menthone (5.18%), beta-inone (5.02%), cyclopentadecanolide (4.53%), myristicine (3.67%), alpha-pinene (3.58%), thymole (3.19 %) and isomenthone(3.14%). In this study also we evaluated the antibacterial activity of essential oil of Fumaria vaillantii Loisel against the growth of clinical isolates of Staphylococcus aureus and Escherichia coli using agar disc diffusion method. The results showed that the antibacterial activity of the essential oil was well.

In the present study, the adsorption of crystal violet in aqueous solution by nettle leaf was studied. Variables such as pH, concentration of crystal violet dye, adsorbent dose and contact time were optimized. Results showed that the optimum pH range to remove crystal violet dye was 2-6 and contact time 180 min. The Langmuir and Freundlich and Tempkin’s equation for adsorption process were also studied and the experimental data fitted well to the Langmuir isotherm.

The Taguchi method, a robust experimental design, was used for optimization of synthesis of a ZnO nanoparticle. The Taguchi method was applied for the experimental and standard 9 orthogonal arrays (OA) with four factors and three levels for each factor. In the synthesis of the ZnO nanoparticle, zinc acetate, reaction temperature, reaction time and monomer ratio (AA/AAm) were used as important factors. After analyzing with analysis of variance (ANOVA) results showed that minimum particle size for optimizing final product was found to be 30 nm. Synthesized ZnO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques.