Theoretical treatment of IO-X (X = N2, CO, CO2, H2O) complexes.

Iodine monoxide (IO) is an important component of the biogeochemical cycle of iodine. For instance, it is present in the troposphere, where it plays a crucial role in the physical chemical processes involving iodine containing compounds. Here, we present a theoretical study on a series of atmospherically relevant complexes of IO with N2, CO, CO2 and H2O, where their structural and spectroscopic properties and their interaction energies are computed. Calculations are carried out by means of ab initio post Hartree-Fock (RCCSD(T) and RMP2) methods and density functional theory DFT (PBE0 and M05-2X) based approaches with and without the inclusion of dispersion correction. After comparison to RCCSD(T), we highlight the good performance of M05-2X(+D3) DFT in describing the bonding between IO and X (X = N2, CO, CO2, H2O). Moreover, we found that the IO-X (X = N2, CO, CO2, H2O) complexes are formed by non-covalent interactions between the two monomers. In sum, we characterized two types of complexes: I-bonded and O-bonded, where the former is more stable. The atmospheric implications of the present findings are also discussed such as in the formation of the iodine oxide particles (IOPs).

Analysis of spinal and muscular activity during flexion/extension and free lifts.

Detailed measurements of the relative contributions of spine motion and pelvic motion during flexion-extension and free lifts (squat-type) are examined. The results are consistent with the conclusion that passive stretching of the ligamentous tissues transmits significant extensor moment in these activities, the power being supplied by the hip extensor complex acting on the pelvis. In addition, certain injuries result in measurable changes in the kinematic parameters that determine the ligamentous involvement, and these changes can be used to help evaluate spinal condition.

The importance of pelvic tilt in reducing compressive stress in the spine during flexion-extension exercises.

An explanation for the importance of pelvic tilt exercises is proposed. This explanation derives from a mathematical model that predicts the existence of a relationship between lordosis (pelvic tilt) and the distribution of stresses within the spine. The model predicts that, for every angle of forward flexion, there is a unique degree of lordosis that will minimize and equalize the compressive stress within the spine. This stress-minimizing posture also is associated with the minimum muscular activity; the balance of the moment is supported by passive stretching of the connective tissues. These predictions were tested by comparing them with empirical values of spinal geometry and muscular activity, as measured simultaneously by an opto-electronic motion analysis and electromyographic (EMG) data collection system.