Effects of activity-rest schedules on physiological strain and spinal load in hospital-based porters

Workers in physically demanding occupations require rest breaks to recover from physiological stress and biomechanical loading. Physiological stress can increase the risk of developing musculoskeletal disorders and repeated loading of the spine may increase the potential for incurring back pain. The aim of the study was to assess the impact of an altered activity-rest schedule on physiological and spinal loading in hospital-based porters. An existing 4-h activity-rest schedule was obtained from observations on eight male porters. This schedule formed the normal trial, which included two 5- and one 15-min breaks. An alternative 4-h schedule was proposed (experimental condition) that had two breaks each of 12.5 min. It was hypothesized that the experimental trial is more effective in promoting recovery from physiological strain and spinal shrinkage than the normal trial, due to the 5-min breaks being insufficient to allow physiological variables to return to resting levels or the intervertebral discs to reabsorb fluid. Ten males performed both test conditions and oxygen uptake VO2, heart rate, minute ventilation VE, perceived exertion and spinal shrinkage were recorded. There were no significant differences in any of the measured variables between the two trials (p > 0.05). Median heart rates were 78 (range 71-93) and 82 (71-90) beats.min(-1) for the normal trial and the experimental trial respectively, indicating that the activity was of low intensity. The light intensity was corroborated by the oxygen uptakes (0.75, range 0.65-0.94 1.min(-1)). Spinal shrinkage occurred to the same extent in the two trials (2.12 +/- 3.16 mm and 2.88 +/- 2.92 mm in the normal trial and the experimental trial respectively). Varying the length and positioning of the rest breaks did not significantly affect the physiological responses or magnitude of spinal shrinkage between the two trials. More physically demanding work than the porters' schedule should induce greater physiological fatigue and spinal shrinkage. The ratio between activity and rest breaks would then become more important.     

128 line photonic switching system using LiNbO3 switchmatrices and semiconductor traveling wave amplifiers

The possibility of a 128-line photonic space division switching system incorporating LiNbO₃ switch matrices and semiconductor traveling wave amplifiers (TWAs) is discussed. System design is considered in terms of the most suitable location for the TWA devices that gives the most practical power margin. Design requirements for a 128-line photonic switching system suitable for a small-sized private branch exchange requirement are presented along with experimental results. It has been shown that a five-stage switch cascade, suitable for such a high-capacity switching system with a power margin of greater than 5 dB in the highest switch loss situation is possible, using low-facet-reflection TWAs. Such TWA devices have been developed in the 1.3-μm wavelength region with maximum fiber-to-fiber gain values of 15 dB. With maximum gain-polarization dependencies of 3 dB, switch losses can be compensated even under TM mode operation     

Experience with reduction mammaplasty following breast conservation surgery and radiation therapy

Little is known about the outcome of breast reduction in the previously radiated breast. With the increased popularity of breast conservation in the management of breast cancer, it is inevitable that more women with breast cancer who have had a breast radiated will be seeking breast reduction. Although it would be expected that reduction of the radiated breast would be more challenging and would yield less-pleasing results, it has been unclear whether reduction in the radiated breast could be safely performed without interfering with mammography and cancer surveillance. Our experience using different techniques in three patients demonstrates that such reductions can be effectively and safely done if certain principles are followed. Pedicles should be designed to be broader and shorter than usual, and breast flaps should be undermined or elevated either minimally or not at all.     

Prolonged neuromuscular blockade with mivacurium in a newborn

Recent reports have demonstrated that puerperal psychosis is preceded by prodromic signs. These signs must be recognized in a multidisciplinary context, opening the way to improved diagnosis, therapy and prognosis. On the basis of our clinical experience, we stress the important of early management in women who present prodromic signs of puerperal psychosis. Specific management relies on intensive psychotherapy with daily sessions centered on filiation. With this approach, the emergence of delusions can generally be prevented, usually allowing an uninterrupted mother-infant relationship. We hypothesize that this approach has a favorable influence on later mother-child interactions and cause profound changes in the mother's psychic organization, resulting in a better long-term prognosis. We illustrate our point with a case report.     

Balance retraining in a hemiparetic patient using center of gravity biofeedback: a single-case study

A single-subject experimental design was used to evaluate the effects of center of gravity biofeedback on retraining balance control in a 72-yr.-old male hemiparetic patient. For both assessment and training the subject stood on dual force-plates enclosed on three sides by a visual surround. A 4-wk. training period consisted of subject-initiated shifts in body weight to control movement of a real-time computer display of the subject's center of gravity. A Sensory Organization Test and evaluation of weight distribution indicated that biofeedback retraining positively affected balance control during dynamic conditions and when the ground support moved forward.