Effect of pelvic-femoral position on vertebral separation produced by lumbar traction

The purpose of this study was to determine the relationship between hip position and the amount of vertebral separation produced by intermittent lumbar traction. Ten subjects received intermittent lumbar traction at a force of 31.8 kg (70 lb) for 15 minutes in each of three positions of hip flexion (supine): 0 degrees, 45 degrees, and 90 degrees. Vertebral separation was measured on lateral roentgenograms by outlining and marking the vertebral bodies and measuring interspaces with fine-point calipers. Except for the T12-L1 interspace, traction produced greater posterior interspace separation as the angle of hip flexion increased from 0 to 90 degrees. These differences were statistically significant at interspaces L4-5 and L5-S1. We found no systematic changes in anterior interspace distance. To produce maximal posterior vertebral interspace separation, pelvic traction should be applied with the hip flexed 90 degrees.

Intracavity dye laser spectroscopy studies of the Ba + N(2)O, Ca + N(2)O + CO, and Sr + N(2)O + CO reactions

A search for gain or absorption on several candidate visible chemical laser transitions has been carried out using the intracavity dye laser probe technique. Absorption was found on the following v'' ? v' bands of the BaO(A(1)Sigma ? X(1)Sigma) bands in the Ba + N(2)O reaction: 0 ? 1; 0 ? 4; 1 ? 1; 1 ? 2, and 5 ? 1. No gain or absorption could be detected on the 7 ? 1, 6 ? 0, and 4 ? 0 bands (sensitivity ~10(-4)/cm). In Ca, Sr + N(2)O + CO flames, absorption was found in the green arc bands of CaO and the red arc bands of SrO. Several new bandhead wavelengths are reported. Our results support assignment of the arc bands to the diatomic metal oxides. Absorptions and enhancements were found on various Sr, Ba, and Ba(+) transitions.

Intracavity dye laser spectroscopy as a gain probing technique

A He-Ne discharge tube with gain at 6328 A , a flashed ruby rod with gain at 6943 A, and a brightly fluorescing flame were each inserted into the cavity of a flashlamp-pumped dye laser. The influence of the two gain media on the dye laser differs significantly, apparently due to their dissimilar saturation characteristics. Refractive index effects were also observed. The flame experiment demonstrates the efficacy of the intracavity technique as a simple relative population probe.

Off-axis unstable laser resonator: operation

An experimental investigation of a novel unstable laser resonator configuration is reported. The purpose of the novel configuration is to maximize the area that can be illuminated with uniform intense flux by a given laser device. This is accomplished by displacing the optical axis of the resonator to one edge of the optical cavity. The results indicate that the change causes no loss of device output power and has little effect on the beam quality. Additional experimental results are presented indicating the sensitivity of resonator performance to misalignment of the off-axis resonator.