Morteza Hosseini

Interaction study of pioglitazone with albumin by fluorescence spectroscopy and molecular docking.

Pioglitazone is a medicine of thiazolidinedione (TZD) class with hypoglycemic (antihyperglycemic, antidiabetic) action. Pioglitazone binding to human serum albumin (HSA) was investigated at different temperatures (290, 300 and 310 K) by fluorescence spectroscopic method. Molecular docking study was also carried out besides the experiments. Experimental results revealed that pioglitazone have an ability to quench the intrinsic fluorescence of HSA tryptophan through a static quenching procedure. The binding constant was determined using Stern-Volmer modified equation and energy transfer mechanisms of quenching were discussed. Thermodynamic parameters were also calculated according to enthalpy changes dependence on different temperatures. According to the theoretical and experimental results, hydrogen bonding was found to play a major role in the interaction of pioglitazone with HSA.

Thermal investigation of Cu–water nanofluid between two vertical planes

In this paper, the natural convection of a non-Newtonian Cu–water nanofluid between two infinite parallel vertical flat plates is investigated. The basic partial differential equations are reduced to ordinary differential equations which are solved analytically using homotopy perturbation method. The comparison between the results from homotopy perturbation and numerical methods are in good agreement which proves the capability of this method for solving this problem. The effects of the nanoparticle volume fraction, dimensionless non-Newtonian viscosity and Eckert number on flow and heat transfer characteristics are examined. The results show that as nanoparticle volume fraction increases, the momentum boundary layer thickness increases with the decrease in the thermal boundary layer thickness.

Determination of Hg(II) ions in water samples by a novel Hg(II) sensor, based on calix[4]arene derivative

A PVC membrane electrode for Hg(II) ions, based on a new cone shaped calix[4]arene (L) as a suitable ionophore was constructed. The sensor exhibits a linear dynamic in the range of 1.0 × 10−6–1.0 × 10−1 M, with a Nernstian slope of 29.4 ± 0.4 mV decade−1, and a detection limit of 4.0 × 10−7 M. The response time is quick (less than 10 s), it can be used in the pH range of 1.5–4, and the electrode response and selectivity remained almost unchanged for about 2 months. The sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, and some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Hg2+ ions with potassium iodide, and the direct determination of mercury content of amalgam alloy and water samples.

A study of quenching and enhancing effects of some amino acids on peroxyoxalate chemiluminescence of rhodamine 6G

The quenching effect of l-cysteine, l-methionine on strong chemiluminescence of bis(2,4,6-trichlorophenyl)oxalate-H(2)O(2) system in the presence of rhodamine 6G was studied. The chemiluminescence parameters were evaluated from computer fitting of the resulting intensity-time plots. These systems resulted in Stern-Volmer plots in the quencher concentration range of 4.0 x 10(-6) to 4.0 x 10(-5)M, with K(Q) values of 1.64 x 10(4) and 8.0 x 10(4)M(-1) for l-metionine and l-cysteine, respectively. Also, this study describes the employment of l-histidine as a highly potent signal enhancer in peroxyoxalate chemiluminescence in the presence of rhodamine 6G.