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At least 181 records · Page 10Linked to original sources
PubMed1980

Analog computer monitoring and evaluation of a dosing nomogram for gentamicin based on the c'min-method: Part I.

Present methods for dosing gentamicin are based on usual doses or desired peak concentrations. The effective range is believed to be between 3 and 10 micrograms/ml. A method is proposed to maintain the minimum steady state concentration at a desired MIC with peak concentrations not exceeding 10 microgram/ml. After determination of the log serum creatinine-log creatinine clearance relationship in a specific population group (Peruvian mestizos), a nomogram for dosing gentamicin was developed. The applicability of the nomogram or the corresponding equation upon which the nomogram was based was tested in patients for desired MIC of 0.5, 1.0, 1.5 and 2.0 microgram/ml, and the actual c'min values obtained were compared with predicted levels. Using a correction factor, the nomogram is applicable for the United State and European population. The importance of drug level monitoring is emphasized.

Computers, Analog↗
PubMedDate not supplied

Can a shuttlebox computer analog be used to condition human avoidance behavior?

Freedman (1990) introduced a computer analog of the shuttlebox paradigm and presented results to show that this analog could be used for studying human avoidance conditioning. In the present study, a first experimental phase was conducted to test how the fact that the tone was considered aversive in the instructions and the intensity of this tone affect avoidance behavior. In a transfer-of-control test phase, it was tested as to whether the warning stimulus presented as a cue to the aversive stimulus had acquired either aversive or informative quality. An effect of instructions was observed for both levels of the auditive stimulus, and a stimulus effect was found for those groups that were given the instructions that described the tone as aversive. In the case of subjects who in the first phase achieved a certain learning criterion, it was recorded how often they in the second phase selected a condition in which the warning signal of the first phase was not presented. No transfer of control was observed. Thus, no positive evidence was found indicating that Freedman's computer analog could be used for studying human avoidance conditioning.

Adult↗
PubMed2002

Glow discharge in microfluidic chips for visible analog computing.

Here we present a novel visible analog computing approach for solving a wide class of shortest path problems. Using a microfluidic chip for computation, based on the lighting up of a glow discharge, the solution to maze search problems, the solution of a network shortest path and k-shortest paths problems and the practical application of finding the shortest paths between several landmarks from a street map are presented. The solution and visible display (in real time) for these problems shows only a small difference in practical problem solving time among problems with varying differences in size.

Journal Article↗
PubMed1975

Calcium movements controlling mammalian myocardial contractility: analog computation of contractile behavior assuming a multicompartmented model.

We present a model to be displayed on a medium scale analog computer, which describes excitation-contraction (E-C) coupling of the mammalian myocardium in terms of calcium movements occurring, on a sarcomere level, in a multicompartment system, Despite the fact that its mathematical formulations are oversimplifications of the mechanism involved, because the number of differential equations had to be limited, the model predicts with fair accuracy a large variety of inotropic phenomena thought to be the result of factors influencing cardiac E-C coupling in one way or another. Therefore, in its basic assumption, the overall concept might be correct, and if so, it should be possible to use the model in order to make predictions which can be tested experimentally and can help in understanding results which are otherwise difficult to interpret.

Action Potentials↗
PubMed1978

Problems in the kinetic evaluation of capacity-limited processes by means of the analog computer MEDA 82 T.

A method for the calculation of dose-dependent pharmaco-kinetics by means of a combined zero and first-order model at the analog computer is presented. The results of the combined model can be converted into Michaelis-Menten parameters using simple equations. The method is usable for i.v. injection and for e.v. modes of application in the case of cmax greater than c = co/e.

Computers, Analog↗
PubMed1976

Analog computer assisted beat-by-beat measurement of stroke volume and related variables in man.

A technique for the beat-by-beat measurement of stroke volume is described. Aortic blood velocity signals are obtained from a catheter-mounted electromagnetic velocity transducer and analysed by a purpose-built analog computer. The stroke volume is computed by integration of each period of systolic forward flow using the velocity signal as its sole input. Automatic compensation of flowmeter drift is incorporated and inappropriate triggering of integration by diastolic artefact is prevented by applying both amplitude and duration criteria for the recognition of systolic forward flow. Early diastolic reverse flow is excluded from integration. The cardiac output, mean aortic flow per beat, and interbeat interval are also computed from the velocity signal. With aortic pressure as an additional input signal the mean arterial pressure per beat and systemic vascular resistance can be computed. The computer outputs are calibrated by a manual method. Preliminary studies comparing values for the cardiac output measured by this system and the direct Fick technique have indicated an excellent correlation between the two methods.

Aorta↗
PubMed1978

Age-dependent disposition of amobarbital: analog computer evaluation.

Previously published observations on 4-hour and 24-hour amobarbital blood levels in two groups of subjects (ages 20--40 and over-65) were analyzed with use of an analog computer and literature data for the rate constants of absorption, distribution and metabolism. It was found that the volume of distribution did not change with age, and the increase in biologic half-life from 22.8 hours in the young subjects to 86.62 in the elderly subjects was due to a decreased rate of metabolism. When the one-point method is used, the size of the nightly dose of amobarbital should be reduced in elderly subjects from 200 mg to 50 mg in order to maintain the same steady-state blood levels found in younger subjects.

Adult↗
PubMed1976

The effect of various stains on quantitative agarose-gel electrophoresis: evaluation of the results with the aid of an analog computer.

The effect of dyes of varying purity and with different binding mechanisms on quantitative electrophoresis was examined with the aid of agarose-gel electrophoresis, the phoretogram curves being evaluated with an analog computer. Concurrent quantitative results were obtained with the three dyes tested, viz. Amido Black 10 B, Ponceau Red S and Procion Brilliant Blue. It is concluded that no falsification of electrophoresis results will be caused by dyes with colour-producing secondary components.

Amido Black↗
PubMed2000

A model for fast analog computation based on unreliable synapses.

We investigate through theoretical analysis and computer simulations the consequences of unreliable synapses for fast analog computations in networks of spiking neurons, with analog variables encoded by the current firing activities of pools of spiking neurons. Our results suggest a possible functional role for the well-established unreliability of synaptic transmission on the network level. We also investigate computations on time series and Hebbian learning in this context of space-rate coding in networks of spiking neurons with unreliable synapses.

Action Potentials↗