Identification of the Mass and Stability Interval of Strong Potential in Heavy Mesons

In this paper, we have calculated the masses of mesons containing t-quark and their spins’ coupling coefficients. This was achieved by solving Lippmann-Schwinger equation for the quark-antiquark bound state of heavy mesons in configuration space. Heavy meson masses submitted criteria for the strong nuclear interactive potential between two quarks. We investigated the stability of a few suitable potentials and offered the best of these potentials for heavy mesons.     

Sustained release drug delivery using supramolecular hydrogels of the triblock copolymer PCL–PEG–PCL and α-cyclodextrin

Supramolecular hydrogels (SMGel) have attracted much attention as a drug and gene delivery system in recent years. In this study, SMGels based on the tri-block copolymer of poly-ε-caprolactone–polyethylene glycol–poly-ε-caprolactone (PCL–PEG–PCL) and α-cyclodextrin (α-CD) were prepared and evaluated for the delivery of two model drugs, naltrexone hydrochloride and vitamin B₁₂. Tri-block copolymers were synthesized easily in 15 min by ring-opening polymerization using the microwave irradiation technique, and their structures were determined by gel permeation chromatography and nuclear magnetic resonance methods. SMGels composed of various concentrations of the copolymer and α-CD were prepared and characterized for their rheological behaviour, their gel formation time and in vitro drug release profile. The results indicated that copolymers with a PCL to PEG ratio of 1:4 are suitable for SMGel preparation. The most viscose system with good syringeability was prepared by mixing 12 % wt α-CD and 10 % wt of copolymer. The gelation was found to occur within a minute after mixing. The viscosity of the hydrogel systems was determined as a function of shear rate. Finally, in vitro B₁₂ release through the hydrogel systems was studied. Up to 80 % of Vitamin B₁₂ was released through this system during a period of 20 days. Rheological evaluation revealed that the hydrogel has shear thinning properties, and the system regained its ground rheological state in a time dependent manner. Polymer concentration did not affect the drug release profiles. Finally, it was concluded that such systems are appropriate drug delivery systems due to their ability to provide a controlled drug release profile and their shear thinning thixotropic behaviour, which makes them syringeable and injectable.     

A mixed integer nonlinear programming model for the optimal repair–replacement in the firm

Optimal repair–replacement problem is an important aspect of economic decision making at the firm and aggregate levels. In this paper, we extend the continuous time optimal replacement model in the firm under technological progress by considering the possibility of repairing/replacing the machines during their lifetime period. In our model, two possible decisions can be recognized by the managers in which the machines are repaired under the efficiency condition or replaced under the availability of technological progress in the firm. As a special case, we restrict the model to the more real case in which all the growth, purchase price and repair cost functions are assumed to be in the exponential form. The solvability of the model in this case is also discussed.     

Tjon Lines and Scaling Limit in Four-Body Systems

The fixed-slope correlation between tetramer and trimer binding energies, observed by Tjon in the context of nuclear physics, is mainly a manifestation of the dominance of the two-nucleon force in the nuclear potential, which makes the four-body scale on the order of the three-body one. In a more general four-boson case, the correlation between tetramer and trimer binding energies has a non-fixed slope, which expresses the dependence on the new scale. The associated scaling function generates a family of Tjon lines. This conclusion relies on a recent study with weakly-bound four identical bosons, within a renormalized zero-range Faddeev-Yakubovsky formalism.     

Heavy Mesons Spectroscopy

In this paper, Lippmann-Schwinger equation is solved by using Martin and Cornel potentials to calculate $b\bar{c}$ energy levels. The results for some energy levels which are not observable, such as those of $t\bar{t}$ in its short half-life are also predicted. Our calculated energy levels are in good agreement with results of other groups. The stability interval for Yukawa-Linear potential is also studied by investigating the spectrum of eigenvalues.     

Momentum space calculations of the binding energies of argon dimer

The binding energies of argon dimer are calculated by solving the homogeneous Lippmann-Schwinger integral equation in momentum space. Our numerical analysis using two models of argon-argon interaction developed by Patkowski et al. not only confirms the eight argon dimer vibrational levels of the ground state of argon dimer (ie, for j = 0) predicted by other groups but also provides a very precise means for determining the binding energy of the ninth state which its value is a matter of discussion. Our calculations have been also extended to states with higher rotational quantum number j and we have calculated the energy of all 174 bound states for both potential models. Our numerical results for vibrational levels of the ground state of argon dimer are in excellent agreement with other theoretical calculations and available experimental data.     

Range Corrections to Universal Tetramer Properties

The universal properties of weakly-bound tetramers close to the scaling limit are investigated by solving a subtracted set of Faddeev–Yakubovsky (FY) equations for identical bosons with a zero-range interaction. The solution demands a four-body scale independent of the trimer properties. Furthermore, the effect of a finite effective range is introduced in the FY equations, which we show produces results that are distinct from the scale variation. In particular range effects to two universal scaling functions for the tetramers are investigated. The correlation between successive tetramer energies corresponding to states within two Efimov trimer energies, proposed before and studied close to the unitary limit; and the correlation between the position of the four-atom recombination peaks. In this case, we found a shift in the scaling function due to the range, which can be associated to the shift of the data found for caesium atoms, with respect to zero-range calculations, due to a nonvanishing range in the actual experimental setups.     

Author Correction to: In silico studies of novel scaffold of thiazolidin-4-one derivatives as anti-Toxoplasma gondii agents by 2D/3D-QSAR,molecular docking,and molecular dynamics simulations

Structural Chemistry - The authors regret that the Acknowledgments of the original version of this article was incorrect.     

A realistic three-dimensional calculation of the 3H binding energy

Recently developed three-dimensional Faddeev integral equations for the three-nucleon bound state with two-nucleon interactions have been solved in momentum space for the Bonn-B potential.     

Sono-synthesis of imidazolidine-2-thione as a base compound of some pharmaceutical products

This work describes the results of investigations carried out to investigate the synthesis of imidazolidine-2-thione as a heterocyclic compound in the presence of ultrasound (sono-synthesis) and in the absence of ultrasound (conventional method). Instead of reflux in the conventional method, the mixture was sonicated indirectly in sono-synthetic method with 500 kHz at different temperatures. Some experiments were also carried out without catalyst with 500 and 900 kHz. In the conventional method, the yield of the reaction was increased by increasing the temperature but in sono-synthetic method, the thermal dependence was different in the range of temperature studied (10-50 degrees C). In the presence of ultrasound, the yield was reached to more than 93% after 1h but in the conventional method it reached only 27% under the same conditions. Comparison was carried out with and without catalyst. It is also possible to achieve a high yield of product under sonication without the use of a catalyst.