Expert systems in histopathology. IV. The management of uncertainty.

Expert systems deal with data that are categorical and conceptual, that represent elements of fuzzy sets and that often, by themselves, do not allow an unequivocal decision. The management of uncertainty in expert systems thus becomes a crucial issue. It involves defining measures of uncertainty and procedures for combining accumulating evidence in a manner that properly considers the dependence structure of diagnostic clues. Probability theory offers valuable procedures for uncertainty assessment; however, their practical application in the domain of quantitative histopathology and histopathologic diagnosis can be problematic.     

The tetrazolium-formazan system: design and histochemistry.

Our increasing knowledge about the chemistry and the correlations between chemical structure and histochemical properties of the tetrazolium/formazan system is resulting in: a better understanding of existing histochemical tetrazolium techniques; the selection of optimal tetrazolium salts for qualified use in histochemistry, cytochemistry and biochemistry; both qualitative and quantitative improvements in histochemical techniques for purposes demonstrating the activities of various dehydrogenating enzymes; an extended insight into the "state" of the tested biological object by means of tetrazolium indicators with special properties; and the combination of histochemical enzyme determination with further morphological techniques. This article has attempted to illustrate the progress in the use of the tetrazolium/formazan-system for histochemical purposes.     

Limiting sedimentation and diffusion coefficients of polyelectrolytes. The charge effect

General expressions relating the sedimentation and diffusion constants of polyelectrolytes to the friction properties of ionic components in multicomponent systems have been derived. A quantitative explanation of the charge effect with respect to the addition of a low-molecular-weight salt is given; special attention is laid on limiting laws according to the salt-to-polymer concentration ratio. The theory is applied to a simple model, the infinitely long rod-like model, to illustrate the peculiar aspect of the charge effect in presence of salt.     

The energetics of embryonic growth and development. I. Oxygen consumption, biomass growth, and heat production.

A quantitative phenomenological model to describe the relationships between biomass growth rate, oxygen consumption, and heat production in developing embryos has been developed and tested using a wide range of experimental data. The model employs generalized material and energy balances, principles of enzyme kinetics, and an overall metabolic model scheme based on known biochemical principles. The phosphorylation concentration ratio of ATP and ADP occurs naturally and becomes a significant parameter in the analysis. The model is applied to the growth of Escherichia coli, Oryzias latipes, chick spinal cord, and whole chicken eggs. Excellent agreement between the model and the experimental data is obtained. In a succeeding paper (Part II) environmental effects and growth efficiency are discussed.     

Linkage between quantitative and marker loci. V. Joint analysis of various marker and quantitative traits

New versions are suggested to analyse marker and quantitative characters combinations. Possible modes of application of the algorithms developed for recombination analysis are discussed, including: 1) the estimation of crossing-over frequency between markers with incomplete penetrance, 2) the quantitative character variability account to analyse genetic interference, 3) search for genetic factors affecting a set of quantitative characters, 4) the evaluation of differences between male and female meiosis at the crossingover level etc.     

The balance between adaptability and adaptation.

In his 1983 book, Adaptability, Michael Conrad explored the quantitative relationship between adaptability and adaptation using the conditional 'entropy' of information theory as his primary tool. The conditional entropy can be used to estimate the connectivity of the network of system exchanges, a key indicator of system stability. In fact, the May-Wigner criterion for the stability of linear dynamical systems can be recast using the conditional entropy to help identify the boundary along which adaptability and adaptation are exactly in balance-the 'edge of chaos' as it is popularly known. Real data on networks of ecosystem flows indicate that in general these systems do not exist nigh upon the edge of chaos, but rather they populate a much wider 'window of vitality' that exists between the realms of chaotic and deterministic dynamics. It appears that the magnitudes of network flows within this region are distributed in power law fashion. The theory also suggests that an absolute limit to the connectivity of natural self-organizing systems exists, at approximately 3.015 effective connections per node.     

The assay of dipeptides using fluorescamine and its application to determining dipeptidase activity.

The differing effect of pH on the reaction of fluorescamine with amino acids and peptides has been utilized to develop a method for the quantitative estimation of peptides in the presence of amino acids. This method has been applied to the measurement of dipeptidase activities in human jejunal aspirates.     

The structure-activity relationship of skin carcinogenicity of aromatic hydrocarbons and heterocycles.

From a study of 239 aromatic and heteroaromatic compounds causing skin cancer in mice, a quantitative structure-activity relationship has been derived. Carcinogenicity depends heavily on the relative hydrophobicity of the chemicals as defined by octanol/water partition coefficients (log P). It is also correlated with the energy of the highest occupied molecular orbital and the presence of substituents on the L and K regions of the carcinogen. The results are discussed in terms of the bay region concept for carcinogenic activity.     

Avian prey-dropping behavior. I. The effects of prey characteristics and prey loss

Numerous species of birds break hard-shelled prey items by droppingthem from a height. This intriguing prey-extraction method providesan excellent opportunity for studying foraging behavior becausea single, easily measurable quantity—height of drop—maybe influenced by a wide variety of identifiable characteristicsof the prey (e.g., breakability, weight) and social environment(e.g., alone or in the presence of kleptoparasites). Using adynamic, state variable modeling approach, this paper presentsthe first theoretical framework for avian prey-dropping systemsthat incorporates the diversity of prey characteristics andsocial situations. The model yielded a series of qualitativepredictions about prey-dropping behavior that can be testedreadily in any prey-dropping system. In particular, the results indicatedthat quantitative and qualitative differences in item breakability andpotential kleptoparasitism should have a significant effecton the height and pattern of prey dropping.     

The mechanisms of defense and dreaming.

This study examined the degree to which the phenomenological experience of dream intensity and its components are correlated with repression, splitting, and other defense mechanisms. The Dream Intensity Scale, Marlowe-Crowne Social Desirability Scale, Splitting Scale, Defense Style Questionnaire-40, and other related measures were administered to 583 subjects. It is demonstrated that repression as a personality trait is inversely and moderately related to the quantitative aspect of dream intensity (i.e., frequencies of dream awareness, nightmares, and multiple dreams in a single night) but does not influence qualitative sensory experiences in dreams (e.g., hearing sounds in dreams). Moreover, the present findings indicate that the more repressed people are, the less likely they are to report splitting and immature defenses, and the less frequently they experience dreams, with the effect of repression on defenses being greater than that on dream intensity. Accordingly, if both dreams and defense mechanisms are the critical materials to work through in a treatment, then starting with the former may be conducive to the therapeutic progress by provoking less resistance from the client. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Fluxes and metabolic pools as model traits for quantitative genetics. I. The L-shaped distribution of gene effects

The fluxes through metabolic pathways can be considered as model quantitative traits, whose QTL are the polymorphic loci controlling the activity or quantity of the enzymes. Relying on metabolic control theory, we investigated the relationships between the variations of enzyme activity along metabolic pathways and the variations of the flux in a population with biallelic QTL. Two kinds of variations were taken into account, the variation of the average enzyme activity across the loci, and the variation of the activity of each enzyme of the pathway among the individuals of the population. We proposed analytical approximations for the flux mean and variance in the population as well as for the additive and dominance variances of the individual QTL. Monte Carlo simulations based on these approximations showed that an L-shaped distribution of the contributions of individual QTL to the flux variance (R(2)) is consistently expected in an F(2) progeny. This result could partly account for the classically observed L-shaped distribution of QTL effects for quantitative traits. The high correlation we found between R(2) value and flux control coefficients variance suggests that such a distribution is an intrinsic property of metabolic pathways due to the summation property of control coefficients.     

The density of microflora in the oral and pharyngeal cavities.

A method for quantitative assessment of the microbial density on the mucous membranes in the oral and pharyngeal cavities is described. The results of the assessment are in agreement with the theoretical assumption based on the existence of a natural electrostatic filter. The highest density of microbes is on the tonsils where the positive pole of the filter is situated, so that a synergism between the defensive immunological role of the tonsils and the bioelectric potential pattern is obvious. The microbial densities in the oral cavity are more or less interdependent whereas the findings on the pharynx rear wall are isolated being probably perturbed by repeated swallowing.     

Genetic studies of human apolipoproteins. XI. The effect of the apolipoprotein C-II polymorphism on lipoprotein levels in Nigerian blacks

The human apolipoprotein C-II locus exhibits genetically determined structural polymorphism in United States and African blacks. In the present study, we have investigated the effect of the apoC-II polymorphism on quantitative serum levels of total cholesterol, total high density lipoprotein (HDL) cholesterol, cholesterol in high density lipoprotein subfractions, low density lipoprotein (LDL) cholesterol, and triglycerides (TG) in a sample of 368 unrelated Nigerian blacks. The frequencies of the APOC-II*1 and APOC-II*2 alleles in the samples were 0.947 and 0.053, respectively. In males, the effect of the APOC-II*2 allele was to lower the total serum cholesterol and LDL-cholesterol levels by 13.28 mg/dl and 10.55 mg/dl, respectively, relative to the common allele, APOC-II*1. In females, the effect was to lower total plasma cholesterol by 4.49 mg/dl and LDL-cholesterol by 3.21 mg/dl. The effect of apoC-II on quantitative lipoprotein levels is shown to be independent of variation at the linked apoE locus, but the products of the two loci interact in determining overall quantitative phenotypes.     

The function of hemocyanin in respiration of the blue crab Callinectes sapidus.

Blood PO2 in the blue crab Callinectes sapidus, a very active species of tropical origin, is lower at 22 degrees C than that of larger crabs in colder waters. These low oxygen levels permit its hemocyanin to be highly oxygenated at the gill, and to deliver almost half of its oxygen to the tissues in resting animals. Sustained muscular activity results in conspicuous decreases in blood PO2, pH and hemocyanin oxygenation. Although the venous reserve is fully utilized, hemocyanin oxygenation at the gill decreases so much that there is no change in its total quantitative function. The large Bohr shift becomes functional during activity, but its quantitative importance is not clear.