Identification of potential inhibitors of coronavirus hemagglutinin-esterase using molecular docking,molecular dynamics simulation and binding free energy calculation

Molecular Diversity - The pandemic outbreak of the Corona viral infection has become a critical global health issue. Biophysical and structural evidence shows that spike protein possesses a high...     

Ni(II) complexation to amorphous hydrous ferric oxide: an X-ray absorption spectroscopy study

Ni(II) sorption onto iron oxides and in particular hydrous ferric oxide (HFO) is among the important processes impacting its distribution, mobility, and bioavailability in environment. To develop mechanistic models for Ni, extended X-ray absorption fine structure (EXAFS) analysis has been conducted on Ni(II) sorbed to HFO. Coprecipitation revealed the formation of the metastable alpha-Ni(OH)(2) at a Ni(II) loading of 3.5 x 10(-3) molg(-1). On the other hand, Ni(II) formed inner-sphere mononuclear bidentate complexes along edges of FeO(6) octahedra when sorbed to HFO surfaces with Ni-O distances of 2.05-2.07 A and Ni-Fe distances of 3.07-3.11 A. This surface complex was observed by EXAFS study over 2.8 x 10(-3) to 10(-1) ionic strength, pH from 6 to 7, a Ni(II) loading of 8 x 10(-4) to 8.1 x 10(-3) molg(-1) HFO, and reaction times from 4 hours to 8 months. The short- and long-range structure analyses suggest that the presence of Ni(II) inhibited transformation of the amorphous iron oxide into a more crystalline form. However, Ni(2+) was not observed to substitute for Fe(3+) in the oxide structure. This study systematically addresses Ni(II) adsorption mechanisms to amorphous iron oxide. The experimentally defined surface complexes can be used to constrain surface complexation modeling for improved prediction of metal distribution at the iron oxide/aqueous interface.     

Elastic scattering of electrons from He, Ne and Ar atoms at 35 keV

The eikonal Born series (EBS) method is applied to the elastic scattering of electrons by He, Ne and Ar atoms at 35 keV. The differential cross-sections are compared with the numerical results obtained by the partial-wave analysis. A simple analytical Dirac-Hartree-Fock-Slater (DHFS) field is used for these atoms. The results are also obtained by Wallace, Das and modified Das method. An oscillatory nature and a strong forward peak in the cross-section are not found at 35 keV. The results are nearer to the experimental data of Coffmann and M. Fink as well as numerical results based on relativistic partial-wave treatment.     

Growth and Dislocation Etching of InBi0.8Sb0.2 Single Crystal

InBi_0.8Sb_0.2 single crystals have been grown by zone melting method. The freezing interface temperature gradient of 3 °C/cm has been found to yield the best quality crystals obtainable at growth velocity 1.0 cm/hr. Traingular features have been obtained on the free surface of the as grown crystal. A new dislocation etchant based on nitric acid has been found to give reproducible etch-pitting on the cleavage surface. Standard tests for a dislocation etchant have been carried out and results are reported.     

Generation of sub wavelength super long dark channel using azimuthally polarized annular multi-Gaussian beam

We investigate the interesting focal properties of phase modulation azimuthally polarized annular multi Gaussian beam employing a high numerical aperture (NA) lens on the basis of vector diffraction theory. We observe that our proposed system generates a sub wavelength focal hole of \(0.43 \uplambda \) having large uniform focal depth of \(84 \uplambda \) . This kind of nondiffracting focal hole is called dark channel, which may have applications in atom optical experiments, such as with atomic lenses, atom traps, and atom switches.     

Incorporation and controlled release of silyl ether prodrugs from PRINT nanoparticles

Asymmetric bifunctional silyl ether (ABS) prodrugs of chemotherapeutics were synthesized and incorporated within 200 nm × 200 nm particles. ABS prodrugs of gemcitabine were selected as model compounds because of the difficulty to encapsulate a water-soluble drug within a hydrogel. The resulting drug delivery systems were degraded under acidic conditions and were found to release only the parent or active drug. Furthermore, changing the steric bulk of the alkyl substituents on the silicon atom could regulate the rate of drug release and, therefore, the intracellular toxicity of the gemcitabine-loaded particles. This yielded a family of novel nanoparticles that could be tuned to release drug over the course of hours, days, or months.