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PubMed1990

Formulation, nutritive value and sensory evaluation of a new weaning food based on sweet corn (Nutrimaiz) dehydrated pulp.

The objective of the present work was to develop a formulation for complementary infant and child feeding employing linear programing as a mathematical model for optimization. High lysine/high tryptophan sweet corn pulp in the dehydrated form was used as the main ingredient. The restrictions imposed on the model were nutrient requirements, adequate protein/energy ratio and minimum cost. The formula derived by the computer (FC) matched the amino acid requirements, the protein/energy ratio (NDPCal%) and was rated high in laboratory tests in terms of sensory qualities. The cost determined for this formula was competitive in relation to commercial products used for the same purpose. Formula A, which contained 5% more sweet corn pulp and 10% less whole powdered milk, did not differ in nutritional, sensorial and functional properties from the formula FC and was chosen for the field acceptability trial because of its lower cost. Formula A had protein efficiency ratio and Biological Value similar to casein for the rat but protein digestibility and net protein utilization were statistically lower (p less than 0.05) for formula A than for casein. Acceptability tested on children who were 8-18 months of age ranged from 80-90%, average value 87%.

Amino Acids↗
PubMed1989

Indirect calorimetry evaluation of dietary protein and animal fat effects on energy utilization of laying hens.

A multichamber indirect calorimeter was constructed and used to measure energy utilization of laying hens. Four basic diets were formulated by a least cost linear program for use in this study. The first diet was formulated to meet the 1984 National Research Council (NRC) recommendations and contained by analysis 14.5% protein, .58% TSAA, and .68% lysine (designated NRC). The second diet (NRCAA) was formulated to the same amino acid specifications without a protein restriction and contained 12.9% protein, .57% TSAA, and .69% lysine. Another pair of diets was formulated with higher protein (HP) and amino acid restrictions. The HP diet contained 16% protein, .67% TSAA, and .85% lysine; whereas the HPAA diet had 14% protein, .68% TSAA, and .86% lysine. Four additional diets were formulated with the inclusion of 3% animal fat, using the same protein and amino acid restrictions as were used to formulate the first four diets. Animal fat supplementation significantly (P less than .05) improved energy balance (retention) of birds fed all formulations compared with the diets without added fat. Formulation of a diet based on amino acid restrictions significantly increased net energetic efficiency of birds fed amino acid levels higher than those recommended by the NRC (79.2 for HPAA vs. 62.1% for HP), but did not significantly affect net efficiency of birds fed the lower amino acid levels (NRC and NRCAA).

Animal Feed↗
PubMed1976

Adrenodoxin reductase-adrenodexin complex.

Adrenodoxin reductase and adrenodoxin have been shown (Chu, J.-W., and Kimura, T. (1973) J. Biol. Chem. 248, 5183-5187) to form a low dissociation constant, 1:1 complex when both proteins are in the oxidized form. We have found that when adrenodoxin: adrenodoxin reductase ratios are varied by increasing the adrenodoxin concentration, with adrenodoxin reductase held constant, an increasing rate of cytochrome c reduction, with NADPH as reductant, is seen up to a ratio of 1:1, indicating that cytochrome c reduction occurs via the protein-protein complex. Spectra observed during titration of this protein-protein complex with NADH were resolved into components by the linear programming method, using a computer program written in Fortran IV. Analysis of the data has shown that the flavoprotein is reduced prior to the iron sulfur protein, and that the midpoint oxidation-reduction potentials (pH 7.5) of the two proteins are -295 and -331 mV, respectively, when both are present in the complex. Complex formation does not alter the potential of adrenodoxin reductase, but changes that of adrenodoxin by -40 mV. Equilibrium constants derived from potential measurements show that the strength of the protein-protein interaction in the complex is unaltered by reduction of adrenodoxin reductase, but is decreased by about 1 kcal due to reduction of adrenodoxin. The low dissociation constants for both oxidized reduced forms of the adrenodoxin reductase-adrenodoxin complex indicate that the complex must remain associated throughout its catalytic cycle. Titration of the adrenodoxin reductase-adrenodoxin complex with the physiologic reductant, NADPH, was followed by EPR and visible spectra, and yielded an order of reduction of the components identical with that seen when NADH was used as reductant. Reduction of the protein-protein complex with NADPH yielded a ternary complex between NADP+, flavoprotein, and iron sulfur protein, with the two electrons located in a "charge transfer" complex between flavoprotein and pyridine nucleotide.

Adrenal Cortex↗
PubMed1990

[The optimization of the dosimetric plan in the intracavity radiotherapy of patients with cancer of the corpus uteri].

The potentialities of mathematical optimization were investigated with respect to dosimetric design of radiation therapy of endometrial cancer patients using AGAT-V and AGAT-VU [correction of Agat-B and Agat-Y] apparatus. The effectiveness of linear programming for creating in a pathological focus and in normal tissues of a dose distribution, meeting clinical requirements to the maximum, was shown.

Brachytherapy↗
PubMed1988

Quantitative management techniques in dietetics: improving practice through technology transfer.

A content analysis of articles appearing chronologically in the Journal of The American Dietetic Association since its inception in 1925 reveals the breadth and depth of management practice in the dietetic profession. This historical review highlights the introduction, demonstration, and adoption of management tools and techniques in the profession, with particular emphasis on quantitative management science techniques. Seven classifications of management science techniques were used for the content analysis. Although applications of forecasting, simulation, linear programming, and queuing models have been reported in the Journal, a gap is evident between the demonstration of management science techniques and operational use of these techniques in dietetic practice. Dietetic researchers, practitioners, and educators have vital roles in facilitating the transfer of quantitative management science technology into operational dietetic practice. Assessment of the state-of-the-art of dietetic management practice relative to proven quantitative management science techniques reveals the need for improved technology transfer to enhance professional ability in both tactical and strategic decision making.

Dietetics↗
PubMed1986

Are larger dental practices more efficient? An analysis of dental services production.

Whether cost-efficiency in dental services production increases with firm size is investigated through application of an activity analysis production function methodology to data from a national survey of dental practices. Under this approach, service delivery in a dental practice is modeled as a linear programming problem that acknowledges distinct input-output relationships for each service. These service-specific relationships are then combined to yield projections of overall dental practice productivity, subject to technical and organizational constraints. The activity analysis reported here represents arguably the most detailed evaluation yet of the relationship between dental practice size and cost-efficiency, controlling for such confounding factors as fee and service-mix differences across firms. We conclude that cost-efficiency does increase with practice size, over the range from solo to four-dentist practices. Largely because of data limitations, we were unable to test satisfactorily for scale economies in practices with five or more dentists. Within their limits, our findings are generally consistent with results from the neoclassical production function literature. From the standpoint of consumer welfare, the critical question raised (but not resolved) here is whether these apparent production efficiencies of group practice are ultimately translated by the market into lower fees, shorter queues, or other nonprice benefits.

Cost-Benefit Analysis↗
PubMed1986

A model to assess the quality-cost tradeoff in nursing homes.

We develop a model for assessing quality-cost tradeoffs as they arise in nurse staffing and task assignment decisions commonly faced by nursing home administrators and industry regulators. As prospective reimbursement schemes and resource utilization groups (RUGs) are implemented, we expect that tradeoffs such as these will become even more critical than they are now. The model permits the inclusion of quality-related considerations, such as restricting tasks to personnel at specified skill levels, requiring minimum staff levels at each skill level, and selective raising of wage rates. The model is also sensitive to changes in patient needs, labor availability, and technological innovations, permitting its use for general staffing purposes. Because it utilizes linear programming techniques, standard computer software can be used to find solutions very quickly, even on a small personal computer. We describe the application of this model to a nursing home in upstate New York, but the procedure is widely applicable to other health care facilities.

Aged↗
PubMed1985

[Results of radiotherapy of lung cancer in women].

Radiation therapy was provided to 38 (11.5%) of 331 lung cancer female patients at the N. N. Petrov Research Institute of Oncology, USSR Ministry of Health. The combination of radiation- and chemotherapy was used in 9 patients. The Rokus, Rad gamma-therapeutic units or a linear accelerator were used for radiation therapy. Daily single focal doses were 1.2-2.0 Gy, the summary dose was 40-60 Gy. Two-five irradiation fields with the choice of optimum conditions on a computer using the linear programming method were used. The lymph outflow tracts were irradiated from isolated fields and in central lung cancer the tumor and mediastinal region (the root, bifurcation and paratracheal lymph nodes on the affected side) were incorporated in the irradiated zone. Five women received split course irradiation. An analysis of the long-term results of conservative therapy of lung cancer in women has shown that radiation therapy or its combination with chemotherapy is the most effective. These results were slightly better than those in men.

Adenocarcinoma↗
PubMed1992

Use of a spreadsheet program for Deming's linear regression analysis.

A spreadsheet program for Deming's linear regression analysis suitable for use with popular software packages such as Lotus 1-2-3 or Quattro is described. The program is controlled by an autoexecuting simple menu of operations allowing use by those with only limited experience of spreadsheet operation. Regression coefficients, identification of suspect outlying data values and confidence limits and graphical displays of fitted regression lines are provided.

Confidence Intervals↗
PubMed1986

A BASIC program for deriving linear regression formulas for intraocular lens power prediction.

We present an original BASIC program written specifically for the ophthalmologist that allows calculation of linear regression formulas for prediction of emmetropic lens power from the surgeon's own data. The program features ongoing data storage, options for analyzing specific ranges (such as longer axial lengths), and calculation of residuals. The program is user-friendly and may be used with minimal computer knowledge. The authors will copy the program at no charge on a user's initialized diskette.

Computers↗
PubMed1985

A general purpose non-linear curve fitting program for the British Broadcasting Corporation Microcomputer.

Software for non-linear curve fitting has been written in BASIC to execute on the British Broadcasting Corporation Microcomputer. The program uses the direct search algorithm Pattern-search, a robust algorithm that has the additional advantage of needing specification of the function without inclusion of the partial derivatives. Although less efficient than gradient methods, the program can be readily configured to solve low-dimensional optimization problems that are normally encountered in life sciences. In writing the software, emphasis has been placed upon the 'user interface' and making the most efficient use of the facilities provided by the minimal configuration of this system.

Algorithms↗
PubMed1987

ISMOD: an all-subsets regression program for generalized linear models. I. Statistical and computational background.

This paper describes a system written to carry out regression analyses under certain generalized linear models that are widely used in biomedical research. These include continuous response models such as the Weibull, log-logistic, log-normal and Cox proportional hazards models used in survival analysis, and also discrete Poisson, binomial and multinomial response regression models. The system fits models, generates residuals and other diagnostic output, and has an all-subsets regression feature. This paper describes the models implemented and gives statistical background; Part II describes the ISMOD system and presents examples of its application.

Biometry↗
PubMed1976

A computer program suitable for fitting linear models when the dependent variable is dichotomous, polichotomous or censored survival and non-linear models when the dependent variable is quantitative.

Given a set of measurements of s explanatory variables corresponding to each experimental unit, a computer program, whose methodological background can be found in [2] has been written in FORTRAN IV language in order to perform regression analyses when the dependent variable is: (i) dichotomous; (ii) polichotomous; (iii) censored survival. In the two former the Cox's [6] linear logistic models are used while in the third one it has been resorted to the models suggested by Feigl and Zelen [8]. The statistical estimation procedure is maximum likelihood and among the different algorithms developed to reach this goal, the one published by Van der Voort and Dorpema [3], has been utilized. Furthermore, when the dependent variable is quantitative, the program is suitable to fit any function non-linear in the parameters; the pertinent function and its first and second derivatives must be provided by the user. In the present version, implemented on a Univac 1106 machine, the program fits directly the Gompertz function.

Computers↗
PubMed1988

A mechanistic and kinetic analysis of the interactions of the diastereoisomers of adenosine 3',5'-(cyclic)phosphorothioate with purified cyclic AMP-dependent protein kinase.

The binding affinities of the diastereoisomers of adenosine 3',5'-(cyclic)phosphorothioate, Sp-cAMP[S] and Rp-cAMP[S], for the cyclic AMP- (cAMP-)binding sites on purified and reconstituted pig heart type II cAMP-dependent protein kinase holoenzyme were determined by measuring the ability of these compounds to displace [3H]cAMP from this enzyme. Sp-cAMP[S], a cAMP agonist, displaced 50% of the [3H]cAMP bound to the holoenzyme at a concentration 10-fold higher than that of cAMP; Rp-cAMP[S], a cAMP antagonist, required a 100-fold higher concentration relative to cAMP. Activation of the isolated holoenzyme, determined as phosphotransferase activity, was measured in the presence of the agonist and in the absence and in the presence of increasing concentrations of the antagonist. The results of fitting the activation data to sigmoid curves with a non-linear-regression program and to Hill plots by using a linear-regression program showed that Rp-cAMP[S] had no effect on Vmax, increased the EC50 values for agonist activation and had no effect on the co-operativity of activation (h). A Ki value of 11 microM was determined for Rp-cAMP[S] inhibition of cAMP-induced activation of purified type II cAMP-dependent protein kinase. Electrophoresis of the holoenzyme on polyacrylamide gels under non-denaturing conditions in the presence of saturating concentrations of the diastereoisomers resulted in 100% dissociation of the subunits with Sp-cAMP[S] and 0% dissociation with Rp-cAMP[S]. Sp-cAMP[S], the isomer with an axial exocyclic sulphur atom, binds to the holoenzyme, releases the catalytic subunit and activates the phosphotransferase activity. Rp-cAMP[S], the isomer with an equatorial exocyclic sulphur atom, binds to the holoenzyme but does not result in dissociation, and thus acts as a competitive inhibitor of phosphotransferase activity.

Animals↗
PubMed1978

BANDSCAN--a computer program for on-line linear scanning of human banded chromosomes.

BANDSCAN, an interactive program for on-line linear scanning of human G-banded chromosomes quantitative analysis is described. This program was written for a Wang 720 C programmable desk calculator associated to the Zeiss scanning photometer MP01. The system can detect up to a maximum of 24 densitometric band peaks found along banded chromosome arms or chromatids, estimate the total arm length and localize bands in terms of their relative positions. The scanning stage under control is always returned to the pre-fixed scanning starting point (centromere) which allows a user to scan the specimen repeatedly at different sensitivities and thus to reject minor bands or suspected chromosome artifacts. This facilitates a better visualization of major bands and chromosome landmarks. A fully formated print-out on band localizations and their relative positions is obtained at the end of each scanning. The possibilities of the application of this program to band mapping of human chromosomes and to the study of small chromosome band aberrations is discussed.

Animals↗
PubMed1985

Multifit: a flexible non-linear least squares regression program in BASIC.

MULTIFIT, a program in BASIC for implementation on microcomputers, has been developed for non-linear least squares regression fitting of enzyme kinetic, pharmacokinetic and other data to specific models. The program contains a simple procedure for insertion of model equations with up to five parameters (to be fitted) up to 3 independent variables and 1 dependent variable, and can be used to generate a family of programs with pre-set model functions.

Computers↗