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Concentration gradients are often used in separations based on chromatographic, electrophoretic and centrifugal methods. In this report, a BASIC computer program for calculating and graphically representing gradients is described. This GRADIENT program is intended to be run on IBM-compatible computers.
A PC-based computer program for quality assessment (QAS) of results obtained by neutron activation analysis (NAA) is described. Program QAS is designed for the quality assurance system based on a routine use of certified reference materials (CRMs) with similar matrix composition as the samples analyzed together with each sample batch. The results obtained for CRMs samples are then compared with certified (true) values and with the results obtained for particular CRM in previous analysis runs. Five various tests are applied to check the quality of NAA results (for CRM and, consequently, for real samples) obtained for a particular analysis run. Control charts for elemental concentrations found in CRM and ranges of results for duplicate aliquots of CRM are displayed to visualize possible discrepancies. The program accepts files transported from gamma-ray spectrometric system ND 683 (based on a PDP 11 computer), extracts and stores reference material results, and prepares a work spreadsheet for each set of results to avoid typist and other kinds of errors.
The paper describes a computer program that retrieves ISTAT codes increasing the efficiency of the retrieving time spent with traditional methods storing the obtained information in a suitable data-base, which may be lately explored by means of commercial programs. To increase the detail of the stored data, many of the official codes have been expanded with an extra character. Some results obtained from an experience conducted at the Pediatric Division of Crema Hospital are also reported.
The use of a computer program for diagnosing acute abdominal pain in children using Bayes' theorem is described and the results of a one-year trial are analysed in order to qualify and quantify the accuracy of the system and to suggest some of the educational benefits that might be obtained. A means of feedback to medical students is described which can localise their weaknesses based on their experiences of real patients and could be used by educators to measure the effectiveness of their courses and the major areas of difficulty being encountered by the students. The computer has in this instance achieved a remarkable degree of accuracy in view of several factors acting against it. Such experience is very encouraging for further endeavour in this area.
A computer program was developed to simplify the conventional method for determining the maximal contractile element shortening velocity at zero load (Vmax) by analysis of pressure-velocity graphs during the isovolumic contraction period. From an uncalibrated left ventricular (LV) pressure signal and its first derivative (dP/dt), the graph relating developed LV pressure (Pd) to the corresponding instantaneous value of (dP/dt)/28 Pd was constructed by the computer. The segment of the graph that encompassed approximately the second half of the isovolumic contraction period, as determined by analysis of the dP/dt waveform, was then extrapolated to provide V'max on the ordinate. This V'max was compared with the conventional Vmax obtained from calibrated LV and aortic pressure signals. In 5 dogs both in the control state and during inotropic (epinephrine, propranolol) and noninotropic interventions (phenylephrine or dextran infusion), a high degree of correlation was found relating V'max and Vmax both derived by either linear (Vmax = 0.91 V'max + 0.14; r = 0.933; P less than 0.001) or exponential (Vmax = 0.99 V'max - 0.06; r = 0.959; P less than 0.001) extrapolation of the pressure-velocity graph to zero load. By use of this program, Vmax can be easily and reliably estimated from the uncalibrated LV pressure signal and its first derivative.
This paper describes the basic principles underlying the development of a computer program for the analyses of dental caries data. A data structure is described which is based on a definition of each tooth or tooth surface in the dentition, using a multi-dimensional co-ordinate system. The basic process for the computer to perform is to count the number of locations which fulfill certain predefined criteria. Programs developed according to these principles will yield exactly the output the individual user is asking for, no more and no less.
We describe a short computer program, which is written in Pascal language, to measure the diameter of circular and elliptical profiles in sections. Coordinate pairs on the microscope stage, corresponding to two or three points of a profile, are input to obtain its diameter. The program enables one to take measurements directly on the microscope, thereby reducing photographic work and caliper measurement. While the program is largely designed for electron microscopy, it also may be useful for light microscopy morphometry.
A new computer program is described, which positions small molecules into clefts of protein structures (e.g. an active site of an enzyme) in such a way that hydrogen bonds can be formed with the enzyme and hydrophobic pockets are filled with hydrophobic groups. The program works in three steps. First it calculates interaction sites, which are discrete positions in space suitable to form hydrogen bonds or to fill a hydrophobic pocket. The interaction sites are derived from distributions of nonbonded contacts generated by a search through the Cambridge Structural Database. An alternative route to generate the interaction sites is the use of rules. The second step is the fit of molecular fragments onto the interaction sites. Currently we use a library of 600 fragments for the fitting. The final step in the present program is the connection of some or all of the fitted fragments to a single molecule. This is done by bridge fragments. Applications are presented for the crystal packing of benzoic acid and the enzymes dihydrofolate reductase and trypsin.
A 1H NMR database computer program has been developed to determine the primary structure of complex carbohydrates. The database contains carbohydrate structures, their corresponding 1H NMR data, and literature references. From an input list of chemical shift values, the program generates an output list of partially or completely matching carbohydrate structures. In order to facilitate the recognition of the matching part of the selected carbohydrate structures, these structures are displayed with the matching structural elements highlighted. This new 1H NMR database, together with the search program described, now provides a fast access to the published 1H NMR data of complex carbohydrates and furnishes easy links to carbohydrate structures. The performance of the program is demonstrated by the analysis of five carbohydrate fractions prepared from a pool of horse serum glycoproteins.
This paper presents a computer program for analyzing disease prevalence data from animal survival experiments in which there may also be some serial sacrifice. The method has been described in Biometrics 35 (1979) 221-234. The user is interrogated about the details of particular models he wishes to fit. Then a generalized EM algorithm is used to compute maximum likelihood estimates of various quantities of interest concerning the effects of treatment, time and presence of other diseases on the prevalences and lethalities of specific diseases of interest.
This paper presents a relatively simple computer program for Scatchard plot analysis of binding data in steroid hormone receptor determination. The program is written in BASIC and adapted to a low-cost desktop calculator. The program is designed to permit data input without demanding extensive technical knowledge of either computer systems or mathematical background of receptor binding assays.
This paper presents the operation of a digital computer program, VECTAN II, for the spatial analysis of the vectorcardiogram (VCG). The program incorporates a unique waveform recognition algorithm based on the spatial vector length which has been shown to perform better than previous algorithms. The waveform analysis employed by the program considers the vectorcardiogram as a three dimensional entity rather than as scalar or planar representations. VECTAN II is designed chiefly to measure and quantify the VCG response of normal subjects to a controlled stress by analyzing one VCG complex every five seconds throughout a long experiment. The program has been used to analyzeom the NASA Johnson Space Center Cardiovascular Laboratory, from the pre- and postflight medical examinations of the Apollo 15, 16 and 17 crewmen, and from onboard Skylab experiments.
This paper presents a computer program for estimating transition probabilities between states in a stochastic model for an illness-death process which incorporates time-dependent covariates. Parameters are estimated by the method of maximum likelihood using the Newton-Raphson iterative procedure. The program provides the standard normal deviate statistics as well as the value of the maximum of the likelihood function which can be used on repeated applications to test hypotheses concerning coefficients associated with covariates. Although this program is demonstrated by using a model with two 'illness' states and two 'death' states, it is also suitable for analyzing data with models involving fewer states, such as the analysis of survival time with covariates assuming a proportional hazard model.
This paper describes a computer program which calculates all possible empirical formulas for each accurately measured mass in a high resolution mass spectrum. The program, MASSFORM, incorporates a novel mechanism for classifying the empirical formulas generated according to their empirical formula. This mechanism makes it possible to use a set of general empirical formulas to aid in the analysis of complex mixtures in much less time than most other such programs. The program is being used as an important aid to environmental studies.
The study of synaptic biopotentials at the neuromuscular junction has proven to be an invaluable tool in understanding the pre- and post-synaptic mechanisms underlying chemical synaptic transmission and exploring the pathogenesis of neuromuscular disorders. Computer technology has become an important part of these experiments as it increases accuracy and automates the process, allowing more data to be collected and quantitatively analysed. This paper presents a computer program for IBM PC compatible computers capable of recording and analysing the spontaneously occurring miniature end-plate potentials (MEPPs), neurally evoked end-plate potentials (EPPs) and muscle fiber action potentials (APs). The program performs its basic analysis immediately following the sampling of biopotentials from a muscle fiber, thus providing the user with immediate feedback on the status of the experiment; 45 parameters of neuromuscular transmission are computed on-line and displayed on the monitor along with the signal-averaged waveforms. After a series of fibers has been recorded, the program will compile the data into summary tables. The program is designed to provide an experimenter with an easy-to-use, comprehensive method of performing electrophysiological measurements and analysis at the neuromuscular junction.
We have written a computer program, BIGPROBE, which facilitates the design of long nucleic acid probes from the partial or complete amino acid sequence of a protein. BIGPROBE relies upon information on codon usage, intercodon dinucleotide frequency, and potential probe self-complementarity. We have examined the accuracy with which the program predicts coding sequences using sample human and rat genes and probe lengths of 30-60 nucleotides. Rat probe sequences selected by BIGPROBE using either codon usage or dinucleotide frequency data alone averaged 86-92% homology with the known exons of the corresponding gene sequences. Predictive accuracy with rat gene probes could be improved to 89-94%, depending upon probe length, by applying codon usage and dinucleotide frequency data in combination. Similar accuracy was achieved for human genes.
PARCAT is a computer program which implements alternative tests for average partial association in three-way contingency tables within the framework of the product multiple hypergeometric probability model. Primary attention is directed at the relationship between two of the variables, controlling for the effects of a covariable. This approach is essentially a multivariate extension of the Cochran/Mantel-Haenszel test to sets of (s x r) tables. A set of scores such as uniform, ridits, or probits can be assigned to categories which are ordinally scaled. In particular, if ridit scores with midranks assigned for ties are utilized, this procedure is equivalent to a partial Kruskal-Wallis test when one variable is ordinally scaled, and is equivalent to a partial Spearman rank correlation test when both variables are ordinally scaled.
Computer programs in FORTRAN IV have been designed to calculate regional blood flow values from injections of gamma radiation-emitting radioactive microspheres. The first program PRSO constitutes a file containing the names of organs, organ groups and systemic haemodynamic variables and data about the isotopes in use. The second program PRSI transfers the data of the particular experiment concerning protocol, systemic haemodynamic variables, organ weights, number of vials belonging to each organ and the radioactivity from each vial into a data file that is subsequently analyzed by the third program PRSII. One of 5 data conditions which later directs calculations in PRSII is determined by PRSI. PRSII deducts background radioactivity, decomposes the spectrum from the mixture of up to 6 nuclides using the "stripping' method, and corrects for isotope decay during the counting period. Depending upon the data condition, PRSII calculates one or more of the following variables: (i) cardiac output (CO); (ii) the distribution of CO; (iii) regional blood flow values and tissue vascular resistances; (iv) the distribution of blood flow within an arterial bed; (v) arteriovenous anastomotic blood flow; (vi) some specified systemic haemodynamic variables; and (vii) blood flow ratios. The systemic and regional haemodynamic data belonging to experiments are saved for later statistical analyses (e.g., mean, standard error of the variables, changes from the base line, comparison between two groups of experiments) by other programs. PRSO, PRSI and PRSII can be operated by investigators with little or no special training in computer use.