The aim of this study was to construct a numerical model of the thiazide-sensitive Na-Cl cotransporter (TSC) that can predict kinetics of thiazide binding and substrate transport of TSC. We hypothesized that the mecha...
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The aim of this study was to construct a numerical model of the thiazide-sensitive Na-Cl cotransporter (TSC) that can predict kinetics of thiazide binding and substrate transport of TSC. We hypothesized that the mechanisms underlying these kinetic properties can be approximated by a state diagram in which the transporter has two binding sites, one for sodium and another for chloride and thiazide. On the basis of the state diagram, a system of linear equations that should be satisfied in the steady state was postulated. Numerical solution of these equations yielded model prediction of kinetics of tkiazide binding and substrate transport. Rate constants, which determine transitional rates between states, were systematically adjusted to minimize a penalty function that was devised to quantitatively estimate the difference between model predictions and experimental results. With the resultant rate constants, the model could simulate the following experimental results: 1) dissociation constant of thiazide in the absence of sodium and chloride;2) inhibitory effect of chloride on thiazide binding;3) stimulatory effect of sodium on thiazide binding;4) combined effects of sodium and chloride on thiazide binding;5) dependence of sodium influx on extracellular sodium and chloride;and 6) inhibition of sodium influx by extracellular thiazide. We conclude that known kinetic properties of TSC can be predicted by a model which is based on a state diagram.
Genetic analysis is used to map genes, including disease loci, to positions within the human genome. Linkage analysis depends on the co-segregation of a gene (locus) and a phenotype through a pedigree, while associati...
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Genetic analysis is used to map genes, including disease loci, to positions within the human genome. Linkage analysis depends on the co-segregation of a gene (locus) and a phenotype through a pedigree, while association analysis, or linkage disequilibrium mapping, depends on measuring deviation from the random occurrence of alleles in a haplotype in unrelated individuals or nuclear families. Complex computer programs may be used in both forms of analysis. In recent years most interest has focused on identifying genes involved in common, multifactorial diseases. Here I review some current and developing techniques of genetic analysis and give references to where further information can be obtained.
The demand for efficiency in OR management and increase in the necessity of surgical documentation require the use of software applications in hospitals. A client-server based OF-planning and documentation system has ...
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The demand for efficiency in OR management and increase in the necessity of surgical documentation require the use of software applications in hospitals. A client-server based OF-planning and documentation system has been in use in the department of orthopedic surgery in Giessen University since 1992 and is being continously further developed. Aside from the lawful requirements, the demands of clinical doctors have been especially considered. The main functions are management of non medical patient data, scheduling and documentation of operations with coding of diagnoses and therapy, tissue banking, implant inventory, on call scheduling, storage of medical video images, clinical word processing and e-mail. With an integrated web-server, MedXS has the capabilities to offer functions accessible over any webbrowser (Netscape(TM), Internet Explorer(TM)) in the internet or intranet. Through the usage of this application clinical procedures could be more efficiently realized and better agreeing positions with the insurance companies could be reached.
In this contribution, we present the derivation, from the strict transient phase equations of enzyme reactions, of the transient phase equations under the usual assumptions that one or more of the reversible steps inv...
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In this contribution, we present the derivation, from the strict transient phase equations of enzyme reactions, of the transient phase equations under the usual assumptions that one or more of the reversible steps involved in the mechanism of the enzyme reaction are assumed to be in rapid equilibrium. Moreover, we present the transient phase equations of all of the species in a general enzyme system model, valid for the partial or total rapid equilibrium conditions, as well as the particular case of the strict transient phase equations. In the case of the rapid equilibrium assumptions, the equations may be given either as functions of the individual rate constants in the reversible steps assumed in rapid equilibrium or as functions of the corresponding equilibrium constants. The steady state equations are easily obtained from the transient phase equations by setting the time --> infinity. We have implemented a computer program, easy to use and with a user-friendly format for the input of data and output of results, which allows the user to derive the symbolic strict transient phase equations and/or those corresponding to the assumption that one or more of the reversible reaction steps are in rapid equilibrium. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.
This paper describes the development of a computer model for simulating the transient operation of a tubular solid oxide fuel cell(SOFC). The model includes the electrochemical, thermal, and mass flow elements th;lt a...
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This paper describes the development of a computer model for simulating the transient operation of a tubular solid oxide fuel cell(SOFC). The model includes the electrochemical, thermal, and mass flow elements th;lt affect SOFC electrical output. The electrochemical and thermal parts of the model were developed and verified separately before they were combined to form the transient model. The results of model verification tests are presented. Transient simulations were conducted with constant reactant flows and constant inlet temperatures. The transient electrical response of the cell to a load change is described.
The moduli and flow diagram of the program SIR99 are described. New phasing algorithms are proposed working both in direct and in reciprocal space. Their cooperative work is able to solve the structures of both small ...
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The moduli and flow diagram of the program SIR99 are described. New phasing algorithms are proposed working both in direct and in reciprocal space. Their cooperative work is able to solve the structures of both small and large molecules. In particular, small proteins can be solved ab initio without any use of prior information and any user intervention. The efficiency of the various algorithms employed by SIR99 has been tested, and the role of the tangent formula clarified. The user is also provided with some practical information concerning the computer power needed.
Step approximations for circular inductive posts in rectangular waveguides are calculated by conformal mapping, for use in mode matching computer programs which cannot handle curved surfaces. 300 parts per million acc...
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Step approximations for circular inductive posts in rectangular waveguides are calculated by conformal mapping, for use in mode matching computer programs which cannot handle curved surfaces. 300 parts per million accuracy is typical for resonant frequencies, requiring only two steps per 90 degrees are for large-radius posts.
To devise a simple and accurate formula for calculating the basal energy needs of individuals in various age groups, an attempt was made to simplify and optimize Harris & Benedict's method along with the WHO/F...
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To devise a simple and accurate formula for calculating the basal energy needs of individuals in various age groups, an attempt was made to simplify and optimize Harris & Benedict's method along with the WHO/FAO/UNU formula using a computer program. Initially, a preliminary structure was determined for the proposed simplified formula. Subsequently, the coefficients of this formula were determined by simulating two million individuals using a computer program and analyzing their basal energy requirements using the Harris-Benedict and WHO/FAO/UNU formulas. The formula was subsequently tested on 452 real male and female subjects aged 3-80 years. Results showed no significant difference in the values calculated by the old and new methods, and therefore confirmed the accuracy of the new formula. (C) 1999 Elsevier Science Inc.
Xfit is a model-building and map viewing program in XtalView that is used by the structural biology community including researchers in the fields of crystallography, molecular modeling, and electron microscopy. Among ...
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Xfit is a model-building and map viewing program in XtalView that is used by the structural biology community including researchers in the fields of crystallography, molecular modeling, and electron microscopy. Among its distinguishing features are built-in fast Fourier transforms that allow users flexibility in map calculations including the creation of OMIT maps and the updating of structure factors to reflect model changes from within the program. Written in C and using the freely available XView toolkit, it is highly portable to almost any X-windows based workstation including Intel-based LINUX systems. Its user interface is designed to aid in facile model-building and contains a semiautomated fitting system that allows the user to interactively and rapidly build chain de novo into an electron density map, The program is highly optimized to allow such features as interactive contour levels and map calculations to be completed within a few seconds. Features in the latest version including phase-combination, solvent-flattening, automated water addition, and small-probe dot contact surfaces, as well as basic design features, are discussed. (C) 1999 Academic Press.
Locating quantitative trait loci (QTL) in mammalian systems has proven difficult due to the lack of genetic control and reproducibility, as well as the expense of maintaining sufficiently large populations for genotyp...
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Locating quantitative trait loci (QTL) in mammalian systems has proven difficult due to the lack of genetic control and reproducibility, as well as the expense of maintaining sufficiently large populations for genotyping and phenotyping. In plants, populations of recombinant inbred lines (progeny bred to homozygosity from a single cross) do not have these problems, Methods developed to identify QTL in a recombinant inbred soybean population provide a basis for analysis of a suitable mammalian population, such as Portuguese water dogs in the United States. The more than 6,000 dogs have accurate pedigrees, available phenotypic data and samples for genotyping, as well as interesting quantitative trait variation, The computer program Georgie allows us to choose large subpopulations with desirable characteristics such as high degrees of consanguinity that capture some of the benefits of recombinant inbred lines in plants, computer simulations extending methods developed for simpler plant populations indicate that QTL with realistic effects can be identified from such subpopulations. Currently we are developing markers and collecting phenotypic and genotypic data from this population to begin the process of unraveling the genetic basis of quantitative traits in dogs.
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