Neutron powder-profile study of chlorofluoromethane.
The crystal structure of chlorofluoromethane, CH(2)ClF, has been determined at 100 and 30 K using indexing, packing considerations and Rietveld refinement of neutron powder profiles. There is only one phase, in monoclinic space group P2(1) and with two molecules in the unit cell occupying general positions. The structure has close packing in several directions and there are weak hydrogen bonds forming zigzag chains.
The adsorption of bromochlorodifluoromethane on pristine and Ge-doped silicon carbide nanotube: a PBC-DFT, NBO, and QTAIM study
In the present investigation, the feasibility of detecting the bromochlorodifluoromethane (BCF) gas molecule onto the outer surface of pristine single-wall silicon carbide nanotube (SiCNT), as well as its germanium-doped structures (SiCGeNT), was carefully evaluated. For achieving this goal, a density functional theory level of study using the Perdew, Burke, and Ernzerhof exchange-correlation (PBEPBE) functional together with a 6-311G(d) basis set has been used. Subsequently, the B3LYP, CAM-B3LYP, ωB97XD, and M06-2X functionals with a 6-311G(d) basis set were also employed to consider the single-point energies. Natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) were implemented by using the PBEPBE/6-311G(d) method, and the results were compatible with the electronic properties. In this regard, the total density of states (TDOSs), the Wiberg bond index (WBI), natural charge, natural electron configuration, donor-acceptor natural bond orbital interactions, and the second-order perturbation energies are performed to explore the nature of the intermolecular interactions. All of the energy calculations and population analyses denote that by adsorping of the gas molecule onto the surface of the considered nanostructures, the intermolecular interactions are of the type of strong physical adsorption. The doped nanotubes have a very high adsorption energy compared with pristine nanotube. Generally, it was revealed that the sensitivity of the adsorption will be increased when the gas molecule interacts with decorated nanotubes and decrease the HOMO-LUMO band gap; therefore, the change of electronic properties can be used to design suitable nanosensors to detect BCF gas.
Stereoselective disposition of ibuprofen enantiomers in infants.
The pharmacokinetics of the enantiomers of ibuprofen were investigated after oral administration of a single 7.6 +/- 0.3 mg kg-1 dose of the racemate in 11 infants. Mean (+/- s.d.) half-lives were 1.6 +/- 0.5 h for S(+) and 1.5 +/- 0.5 h for R(-) and mean (+/- s.d.) AUC values were 31.5 +/- 14.3 mg l-1 h for S(+) and 36.6 +/- 13.8 mg l-1 h for R(-). Since plasma concentrations of the active S(+)-isomer were lower than those reported in adults, a higher dosage might be required in infants.