Air-purifying powered respirator pack utilizing a miniature two-stage air mover

Design and construction of a moderate-weight, battery-powered, positive-pressure respirator pack is described. Design detail of a two-stage air mover is given, along with its adaptation for use as a portable air sampler.     

Diverticulation of the cerebral ventricles: a cause of progressive focal encephalopathy

Diverticulation of the lateral ventricles of the brain has received little attention in the literature on hydrocephalus. From clinical observations on one child and one adult with diverticulation, it is apparent that force of CSF within the diverticulum is greater than that against the normal parts of the ventricular wall. In both cases, regression of focal symptoms occurred after insertion of a shunt.     

Carboxyhemoglobin trend in Chicago blood donors, 1970-1974

An 18% reduction in the carboxyhemoglobin (HbCO) saturation in nonsmoking Chicago blood donors occurred between 1970 and 1974, indicating that current donors are being exposed to a lower average carbon monoxide (CO) concentration than had been experienced by 1970 donors. In contrast to the situation in 1970, when it was discovered that 74% of the nonsmokers in Chicago were being exposed to CO in excess of the amount permitted by the federal air quality standards, in 1974 only 41% of the nonsmokers were being overexposed. The observed reduction in HbCO correlates well with both the ambient CO levels recorded at the air monitoring stations and the reduction in CO emission from automobiles. If the current trend continues, Chicago should reach compliance with air quality standards for CO by 1985. The measurement of HbCO in a representative urban population is an accurate index of actual CO exposure and supplements the air pollution data provided by air monitoring stations.     

Serial carcinoembryonic antigen assays in patients with metastatic carcinoma of prostate being treated with chemotherapy

Serial carcinoembryonic antigen (CEA) assays were conducted in patients with endocrine-unresponsive prostatic adenocarcinoma who were being treated with multidrug chemotherapy. Changes in CEA correlated with the clinical status of the patient in 70 per cent of the determinations and were more accurate than acid phosphatase in monitoring the response to treatment.     

Transplanted neural tissue develops connections with host rat brain

Superior collicular fragments transplanted from fetal to newborn rat brains develop complex internal organization and receive visual afferents from the host providing they lie sufficiently close to the host visual pathways. This system allows investigation in vivo of special affinities between cells of the mammalian central nervous system.     

Numerical techniques for the inverse optimal control problem in limited state feedback systems

The numerical problem of finding the performance index parameters {Q}, for which a given control {u = fx} is optimal, is studied. Two successful algorithms are described for the single input case. Both apply to systems which are optimal within the constraint of limited state availability. The structure of Q must be prespecified to allow only r free parameters (where r is the dimension of the feedback vector). This ensures that the solution is unique. Numerical examples and program listings are included.