Effect of magnetic field on the impurity binding energy of the excited states in spherical quantum dot

The effect of external magnetic field on the excited state energies in a spherical quantum dot was studied. The impurity energy and binding energy were calculated using the variational method within the effective mass approximation and finite barrier potential. The results showed that by increasing the magnetic field, the energy would be increased. The results obtained by this method were compared with the previous investigations.     

Production of cationic 198Au3+ and nonionic 198Au0 for radionuclide therapy applications via the natAu(n,γ)198Au reaction

¹⁹⁸Au (??_max?=?0.96?MeV (98.6?%), ??_max?=?0.412?MeV (95.5?%) and T _1/2 ?=?2.7?days) is a radionuclide with very appealing characteristics. ¹⁹⁸Au has been widely used to treat the uterus, bladder, cervix, prostate, melanoma, breast, skin and other cancers. In the present study, cationic ¹⁹⁸Au⁺³ and nonionic ¹⁹⁸Au⁰ are prepared following thermal neutron irradiation of commercially available natural gold compounds in Tehran Research Reactor via the ^natAu(n,??)¹⁹⁸Au reaction. The prospects in the production of pure ¹⁹⁸Au⁰ and ¹⁹⁸Au⁺³ for radionuclide therapy are discussed and effect of reduction on the activity of radioactive gold is evaluated. Au⁰ particles were synthesized via NaBH₄ reduction of aqueous solutions of hydrogen tetrachloroaurate trihydrate. Then two quartz tubes were charged with cationic ¹⁹⁸Au³⁺ and nonionic ¹⁹⁸Au⁰. After irradiation by thermal neutrons, the samples were analyzed for a period of 1?month by liquid scintillation counter and high purity germanium detector. As a result, ^natAu³⁺ reduction process had no significant effect on the activity of the ¹⁹⁸Au sample. In conclusions, natural gold thermal neutron activation cross section is reasonably high for medical application.     

Inelastic transport through double quantum dot systems

Inelastic transport through double quantum dot systems with coupling between electronic and vibrational degrees of freedom is examined by means of a master equation approach. The current and the conductance are analyzed for both weak and strong interdot couplings. The results show that an asymmetry in the current-voltage characteristic and appearance of negative differential conductance due to electron-phonon interaction. The influence of temperature on the current is studied and found that increasing temperature gives rise to eliminating the current blockade and, thus, removing the Coulomb diamonds in the conductance spectra.     

A Łoś type theorem for linear metric formulas

We define an ultraproduct of metric structures based on a maximal probability charge and prove a variant of ?o? theorem for linear metric formulas. We also consider iterated ultraproducts (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Calculating the jet-quenching parameter in STU background

In this paper we use the AdS/CFT correspondence to compute the jet-quenching parameter in a N=2\mathcal{N}=2 thermal plasma. We consider the general three-charged black hole and discuss several special cases. We add a constant electric field to the background and find the effect of the electric field on the jet-quenching parameter. Also, we add higher derivative terms and obtain the first-order correction of the jet-quenching parameter.     

Gas permeation properties of ethylene vinyl acetate–silica nanocomposite membranes

The effect of silica nanoparticles on the gas separation properties of ethylene vinyl acetate (EVA) copolymer containing 28% vinyl acetate has been investigated. The EVA and hybrid EVA–silica membranes were prepared via thermal phase inversion method. Silica nanoparticles prepared by hydrolysis of tetraethylorthosilicate (TEOS), through the sol–gel mechanism. The prepared membranes were characterized using FT-IR, SEM, DSC and XRD methods. FT-IR and SEM results indicated the nanoscale dispersion of silica particles in polymer matrix. As confirmed by XRD and DSC analyses, increasing the silica content enhances the amorphous regions significantly. Gas permeation of EVA–silica nanocomposite membranes with silica contents of 5, 6 and 10 wt.% was studied for N₂, O₂, CO₂ and CH₄ single gases at pressures of 4, 6 and 8 bar. The obtained results suggest a significant increase in permeability of all gases and an increase in CO₂/N₂ and CO₂/CH₄ gases selectivities upon increasing the silica content. The possible reasons for such behavior were stated and discussed. The pressure dependence of the gas permeabilities of the membranes was also investigated.     

A Thermodynamic Study on the Binding of Human Serum Albumin with New Synthesized Anti Cancer Pd (II) Complex

The thermodynamics of the interaction between new synthesized anti-cancer drug (2,2′-bipyridin n-butyl dithiocarbamato Pd (II), ButPd), and HSA was investigated at pH=7 by isothermal titration calorimetry. A new solvation model was used to reproduce the enthalpies of HSA interaction by ButPd within a broad range of complex concentrations. The solvation parameters attained from the new model were attributed to the structural change and biological activity of HSA. The binding parameters for the interaction of ButPd and HSA indicated that the considerable conformational changes in HSA were not observed after being bound with ButPd. It was found that HSA has three identical and cooperative binding sites for ButPd.     

Non-minimal Maxwell-modified Gauss–Bonnet cosmologies: inflation and dark energy

In this paper we show that power-law inflation can be realized in non-minimal gravitational coupling of electromagnetic field with a general function of the Gauss–Bonnet invariant. Such a non-minimal coupling may appear due to quantum corrections. We also consider modified Maxwell-F(G) gravity in which non-minimal coupling between electromagnetic field and f(G) occurs in the framework of modified Gauss–Bonnet gravity. It is shown that inflationary cosmology and late-time accelerated expansion of the universe are possible in such a theory.     

Electrocatalytic Activity of Immobilized Co(II) on Porous Graphene Aerogels

The highly‐porous graphene aerogel (GA) with BET surface area of 810 m² g^?1 and three‐dimensional structure has been successfully fabricated using the hydrothermal technique. The modified glassy carbon electrode was then prepared by casting the graphene aerogel solution followed by immersing the GA/GCE in Co⁺² solution. The results showed that graphene aerogels improved the adsorption ability of the Co (II) ions. The electrocatalysis of oxygen evolution reaction (OER) at the Co‐GA modified glassy carbon elec‐ trode (Co‐GA/GCE) has been investigated using linear sweep voltammetry (LSV) in alkaline solution. The OER was noticeably enhanced at Co‐GA/GCE, representing a negative shift in the LSV curve at the Co‐GA/GCE compared to that obtained at the bare GCE. The high electrocatalytic activity, good reproducibility and low cost of proposed electrode provides desired characteristics of a potential candi‐ date in the industrial water electrolysis process.     

The salting-out effect and phase separation in aqueous solutions of sodium phosphate salts and poly(propylene glycol)

Phase diagrams and liquid–liquid equilibrium (LLE) data of the aqueous poly(propylene glycol) (PPG) + di-sodium hydrogen phosphate and PPG + tri-sodium phosphate two-phase systems have been determined experimentally at 298.15, 303.15, 308.15, 313.15 and 318.15 K. The effects of temperature and charge on the anion of electrolyte on the binodal curves and tie-lines have been studied and it was found that an increasing in temperature and charge on the anion caused the expansion of two-phase region. The results show that the effect of charge on the anion of electrolyte on the binodal curves becomes smaller by increasing temperatures. It was also found that the concentration of salt, which is in equilibrium with a certain concentration of PPG, decreases by increasing temperature. Based on cloud point values, the energetics of the clouding process has been estimated and it was found that entropy increase is the driving force for biphasic formation.