Electronic, mechanical, and thermal properties of zirconium dioxide nanotube interacting with poly lactic-co-glycolic acid and chitosan as potential agents in bone tissue engineering: insights from computational approaches.

For the first time, the interaction of the Poly lactic-co-glycolic acid (PLGA) and Chitosan (CH) with Zirconium dioxide (ZrO2) nanotube was studied using density functional theory (DFT). The binding energies of the most stable configurations of PLGA and CH monomers absorbed on ZrO2 were calculated using density functional theory (DFT) methods. The obtained results indicate that both CH and PLGA monomers were chemisorbed on the surface of ZrO2. The interaction between PLGA and ZrO2 is stronger than that of CH due to its shorter equilibrium interval and higher binding energy. In addition, the electronic density of states (DOS) of the most stable configuration was computed to estimate the electronic properties of the PLGA/CH absorbed on ZrO2. Also, the molecular dynamics (MD) simulations were computed to investigate the mechanical properties of all studied compounds in individual and nanocomposite phases. MD simulation revealed that the shear and bulk moduli of PLGA, CH as well as Young's modulus increase upon interacting with the ZrO2 surface. As a result, the mechanical properties of PLGA and CH are improved by adding ZrO2 to the polymer matrix. The results showed that the elastic modulus of PLGA and CH nanocomposites decreased with increasing temperature. These findings indicate that PLGA-ZrO2 nanocomposites have mechanical and thermal properties, suggesting that they could be exploited as potential agents in biomedical sectors such as bone tissue engineering and drug delivery.Communicated by Ramaswamy H. Sarma.

Boron nitride nanoclusters, nanoparticles and nanotubes as a drug carrier for isoniazid anti-tuberculosis drug, computational chemistry approaches.

In this work, the ability of B12N12 fullerene-like nanoclusters as a drug carrier for isoniazid anti-tuberculosis drug has been studied by DFT methods. Binding energies in both gas and water phases are reported. The formed bonds between B12N12-FLN and Iso drug are studied and computed using QMAIM method. NPA is computed to obtain the total charges transferred in the B12N12-FLN-Iso drug complexes, NPA obtained values suggested that the cluster may oxidize the coordinated of Iso drug. The charge-transfer energy values are also computed and confirmed that the charges were transferred from the non-bonding lone-pair (n) of N and O atoms orbitals to the σ* orbitals of B and N atoms of B12N12-FLN. Also, the adsorption of Iso drug on BN nanoparticles surface (different sizes and shapes) and BN nanotubes was studied by Monte Carlo simulation. We found that increasing the BN size did not affect significantly on the adsorption energies of Iso drug for all various BN nanoparticles shapes. All adsorption energies obtained by MC calculations are negative values which revealed that the adsorption of the Iso drug molecule on BN surfaces is exothermic, spontaneous and energetically favourable. Also, the stability of B12N12-FLN-Iso drug complex in water explicitly was studied by MD simulations. MD simulation confirmed that iso-B12N12-FLN complexes are stable in the presence of water molecules. So, finally, we deduced that B12N12 fullerene-like nanoclusters can be acted as a drug carrier for isoniazid anti-tuberculosis drug. Communicated by Ramaswamy H. Sarma.

Clinical features, tissue smear and competitive enzyme linked immunosorbent assay as dignostic and prognostic procedures for visceral leishmaniasis in Yemen.

Twenty six Yemeni patients with clinically visceral leishmaniasis (VL) and laboratory abnormalities were subjected to L. donovani species-specific monoclonal antibody (D2) and a competitive enzyme-linked immunosorbent assay (C-ELISA). The results were compared with those obtained by microscopy Giemsa stained tissue smears of bone marrow or splenic aspiration. Of the patients, 51 (82.3%) were positive and 3 (4.8%) were negative by both microscopy and C-ELISA. An additional 8 (12.9%) who were negative by microscopy were positive by C-ELISA. 59 patients were treated with sodium antimony gluconate, 45 (76.3%) were drug responsive and 14 (23.7%) were drug resistant. The C-ELISA of 17 patients before and after chemotherapy showed a significant decrease in percent inhibition of monoclonal antibodies D2 in drug responsive patients. In drug-unresponsive patients the percent inhibition of D2 was unchanged or slightly increased. The results indicate that C- ELISA is more sensitive and specific than microscopy, especially for early diagnosis of VL and to evaluate the success of drug treatment.