The white blood cell differential. Evaluation of rapid impression scanning versus the routine manual count.

A quick, one and a half-minute qualitative microscopic scan was investigated as an alternative approach to the more labor-intensive 100-cell differential white blood cell count. The scanning results of 400 randomly selected hospital cases were compared with the on-line results of the 100-cell counts. Additionally, 50 cases selected to have a high percentage of abnormal results were each scanned and manually counted by four different readers. The results indicate that the scanning differential is equivalent to the 100-cell manual count in the detection of the presence of abnormal cell types such as immature granulocytes and blasts. Its ability to properly estimate the relative proportions of normal cells, especially lymphocytes, however, does not appear as reliable as the manual count. Most importantly, the analysis demonstrates that the scanning differential count exhibits a set of advantages and disadvantages that is complementary to those of the "three-part differential" technic provided by the newer generation automated hematologic analyzers. The authors therefore propose that these two procedures used in combination offer a suitable alternative to the manual 100-cell differential count.

ELF exposure facility for human testing.

A laboratory facility specifically designed for controlled human exposure to 60-Hz electric (0 to 16 kV/m) and magnetic (0 to 32 A/m, B = 0 to 40 microT) fields has been constructed. The facility presents uniform fields under controlled temperature and humidity. Special control systems allow collection of physiological data during, as well as before and after, exposure to electric fields at strengths to 16 kV/m under verified double-blind control. Exposure to continuous or intermittent fields is possible in the facility. The capability of obtaining physiological data during actual exposure to constant or intermittent, 60-Hz fields, and of doing so without either the subject or the experimenter being aware of actual field conditions, is a critical factor in valid experimentation.

Effects of variation in physical effort on frontalis EMG activity.

The physiological mechanisms underlying forehead muscle biofeedback for stress reduction are not well understood. A common hypothesis considers the frontales to be "key muscles" uniquely indexing the degree of tension present in the general musculature. We tested this hypothesis under conditions ranging from relaxation to maximum physical effort. The hypothesis was not supported. Changes in forehead muscle activity were limited primarily to reflecting changes in head and neck muscle tension.