PubMed · 6877330
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1983-09-01. Computer-predicted theophylline kinetics.. https://doi.org/10.1056/nejm198309013090915
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Computerized polysomnographic systems have came into common use in sleep laboratories around the world. Despite potential advantages over standard paper polysomnography, these computerized systems have been minimally evaluated as to accuracy, analysis time, or cost effectiveness when compared to paper. We evaluated the Healthdyne ALICE 3 system for comparability to paper polysomnography in sleep quantification and technician analysis time. Fifty patients were recorded simultaneously both on paper and on the ALICE 3 system and analyzed blindly with summary data from these records being quantified and compared. Five additional patients were studied for epoch-by-epoch analysis. Score-rescore assessments were accomplished for both groups. The results indicate that when allowed to autoscore, this computerized system produced substantial errors in sleep staging (REM sleep time 56.4 + 4.9 minutes vs 73.2 + 8.4 minutes for paper versus computer). This was the case for respiratory (AHI of 26.5 + 4.3 vs 15.3 + 2.6 for paper vs computer) and arousal assessment as well. However, with editing, similar results to those obtained with paper were achieved (REM sleep time -56.4 + 4.9 vs 59.0 + 4.6; AHI -26.5 + 4.3 vs 26.1 + 4.7 for paper and computer respectively), with differences rarely exceeding score-rescore discrepancies. Analysis time was substantially reduced by use of the computer (172.6 + 9.9 vs 79.7 + 4.8 minutes for paper vs computer). Epoch-by-epoch analysis revealed a trend to score toward wakefulness or lighter sleep on computer compared to paper although the differences were small. Respiratory, arousal and PLM scoring were quite similar. In conclusion, this study suggests that the ALICE 3 system with editing can produce results similar to those obtained with paper.
In the past few years two fascinating and new scientific fields, the science of DNA-structure and topology and the theory of molecular computers have been growing independently. The main goal of this paper is to establish an interesting connection between them and to propose a novel paradigm for the future construction of DNA-computing devices based on supercoil energetics. The basic principle of the proposed model can also be applied to describe the communication between topologically closed segments in real genomes, which is believed to take part in the complex process of gene regulation. An implementation of the recent model is proposed by which polynomials of one real variable can be evaluated in a simple in vitro recombination assay.
The growth of yeast cells to high densities at low, but constant, oxygen concentrations is difficult because the cells themselves respire oxygen; hence, as cell mass increases, so does oxygen consumption. To circumvent this problem, we have designed a system consisting of a computer-controlled gas flow train that adjusts oxygen concentration in the gas flow to match cellular demand. It does this by using a proportional-integral-differential algorithm in conjunction with a three-way valve to mix two gases, adjusting their proportions to maintain the desired oxygen concentration. By modeling yeast cell yields at intermediate to low oxygen concentrations, we have found that cellular respiration declines with oxygen concentration, most likely because of a decrease in the expression of genes for respiratory proteins. These lowered rates of oxygen consumption, together with the gas flow system described here, allow the growth of yeast cells to high densities at low oxygen concentrations. This system can also be used to grow cells at any desired oxygen concentration and for regulated shifts between oxygen concentrations.