RESUMO
The structural, vibrational, and electronic properties of new inorganic X-phosphide nanotubes (ch-XPNT), with X = Al, Ga, or In and chirality of (5,5), are investigated. These new NTs display cap-hole ends, with the cap-hole features induced by the nonpassivated ends. Studies are based on density functional theory (DFT) using the M06-2X, PBE, and B3LYP functionals together with the LanL2DZ basis set. All nanostructures have been relaxed by minimizing the total energy, assuming a nonmagnetic nature and a total neutral charge. Note that the cap-hole NTs are terminated by a 10-atom ring, which in turn favors the geometrical ordering and yields stable structures. The (5,5) ch-XPNT are highly electrophilic and nonpolar, in addition to having high solvation energy values. Let us remark that solvation energies are produced by the intermolecular forces that involve the induced dipoles. Structural and vibrational results show that the X-P bonds are single bonds. Finally, results suggest that the inorganic nanotubes are structurally stable with semiconductor features, which means that their functionalization may yield interesting future applications.
RESUMO
Based on density functional theory (DFT) and the semiempirical method PM7, we analyze the encapsulation process of polluting gases and/or their adsorption on different sites, viz., on the inner wall, the outer wall, and on the boron nitride (BN) nanotube ends, with chirality (7,7) armchair. DFT calculations are performed using the Perdew-Burke-Ernzerhof (PBE) functional and the M06-2X method through the 6-31G(d) divided valence orbitals as an atomic basis. Various geometrical configurations were optimized by minimizing the total energy for all analyzed systems, including the calculation of vibrational frequencies, which were assumed to be of a nonmagnetic nature, and where the total charge was kept neutral. Results are interpreted in terms of adsorption energy and electronic force, as well as on the analysis of quantum molecular descriptors for all systems considered. The study of six molecules, namely, CCl4, CS2, CO2, CH4, C4H10, and C6H12, in gas phase is addressed. Our results show that C4H10, C6H12, and CCl4 are chemisorbed on the inner surfaces (encapsulation) and on the nanotube ends. In contrast, the other molecules CS2, CO2, and CH4 show weak interaction with the nanotube surface, leading thereby to physisorption. Our findings thus suggest that this kind of polluting gases can be transported within nanotubes by encapsulation.
RESUMO
Snake venoms are known to have different venom compositions and toxicity, but differences can also be found within populations of the same species contributing to the complexity of treatment of envenomated victims. One of the first well-documented intraspecies venom variations comes from the Mohave rattlesnake (Crotalus scutulatus scutulatus). Initially, three types of venoms were described; type A venom is the most toxic as a result of ~45% Mojave toxin in the venom composition, type B lacks the Mojave toxin but contains over 50% of snake venom metalloproteases (SVMPs). Also, type A+B venom contains a combination of Mojave toxin and SVMP. The use of an anti-disintegrin antibody in a simple Enzyme-Linked Immunosorbent Assay (ELISA) can be used to identify the difference between the venoms of the type A, B, and A+B Mohave rattlesnakes. This study implements the use of an anti-recombinant disintegrin polyclonal antibody (ARDPA) for the detection of disintegrins and ADAMs (a disintegrin and metalloproteases) in individual crude snake venoms of Mohave rattlesnakes (Crotalus scutulatus scutulatus) of varying geographical locations. After correlation with Western blots, coagulation activity and LD50 data, it was determined that the antibody allows for a quick and cost-efficient identification of venom types.
