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Michael Mayersohn - One of the best experts on this subject based on the ideXlab platform.

  • Mayersohn M (2005) Accuracy of allometrically predicted pharmacokinetic Parameters in humans: role of species selection. Drug Metab Dispos 33:1288–1293
    2020
    Co-Authors: Huadong Tang, Michael Mayersohn
    Abstract:

    ABSTRACT: A general equation was derived, which directly describes the mathematical relationship between the allometrically predicted pharmacokinetic (PK) Parameters in humans and the body weights of animal species (along with their corresponding measured PK Parameters). It was shown, with use of the derived equation, that the predicted values in humans, based on combinations of animal species commonly used in allometry, are heavily dependent on certain species, for example, the dog. In Contrast, Parameter values from the rat made no contribution to the predicted human values, as long as the rat was not the smallest species used. Monte Carlo simulations were further performed to examine the species or weight dependence. The cost-effective combinations of animal species, in terms of number and species type, were theoretically examined through simulations. Finally, literature data demonstrated the species or weight dependence predicted from the equation and as illustrated through the Monte Carlo simulations. Appreciation of this species or weight dependence should guide researchers in selecting animal species and designing optimal experiments in the application of allometric scaling

  • accuracy of allometrically predicted pharmacokinetic Parameters in humans role of species selection
    Drug Metabolism and Disposition, 2005
    Co-Authors: Huadong Tang, Michael Mayersohn
    Abstract:

    A general equation was derived, which directly describes the mathematical relationship between the allometrically predicted pharmacokinetic (PK) Parameters in humans and the body weights of animal species (along with their corresponding measured PK Parameters). It was shown, with use of the derived equation, that the predicted values in humans, based on combinations of animal species commonly used in allometry, are heavily dependent on certain species, for example, the dog. In Contrast, Parameter values from the rat made no contribution to the predicted human values, as long as the rat was not the smallest species used. Monte Carlo simulations were further performed to examine the species or weight dependence. The cost-effective combinations of animal species, in terms of number and species type, were theoretically examined through simulations. Finally, literature data demonstrated the species or weight dependence predicted from the equation and as illustrated through the Monte Carlo simulations. Appreciation of this species or weight dependence should guide researchers in selecting animal species and designing optimal experiments in the application of allometric scaling.

Huadong Tang - One of the best experts on this subject based on the ideXlab platform.

  • Mayersohn M (2005) Accuracy of allometrically predicted pharmacokinetic Parameters in humans: role of species selection. Drug Metab Dispos 33:1288–1293
    2020
    Co-Authors: Huadong Tang, Michael Mayersohn
    Abstract:

    ABSTRACT: A general equation was derived, which directly describes the mathematical relationship between the allometrically predicted pharmacokinetic (PK) Parameters in humans and the body weights of animal species (along with their corresponding measured PK Parameters). It was shown, with use of the derived equation, that the predicted values in humans, based on combinations of animal species commonly used in allometry, are heavily dependent on certain species, for example, the dog. In Contrast, Parameter values from the rat made no contribution to the predicted human values, as long as the rat was not the smallest species used. Monte Carlo simulations were further performed to examine the species or weight dependence. The cost-effective combinations of animal species, in terms of number and species type, were theoretically examined through simulations. Finally, literature data demonstrated the species or weight dependence predicted from the equation and as illustrated through the Monte Carlo simulations. Appreciation of this species or weight dependence should guide researchers in selecting animal species and designing optimal experiments in the application of allometric scaling

  • accuracy of allometrically predicted pharmacokinetic Parameters in humans role of species selection
    Drug Metabolism and Disposition, 2005
    Co-Authors: Huadong Tang, Michael Mayersohn
    Abstract:

    A general equation was derived, which directly describes the mathematical relationship between the allometrically predicted pharmacokinetic (PK) Parameters in humans and the body weights of animal species (along with their corresponding measured PK Parameters). It was shown, with use of the derived equation, that the predicted values in humans, based on combinations of animal species commonly used in allometry, are heavily dependent on certain species, for example, the dog. In Contrast, Parameter values from the rat made no contribution to the predicted human values, as long as the rat was not the smallest species used. Monte Carlo simulations were further performed to examine the species or weight dependence. The cost-effective combinations of animal species, in terms of number and species type, were theoretically examined through simulations. Finally, literature data demonstrated the species or weight dependence predicted from the equation and as illustrated through the Monte Carlo simulations. Appreciation of this species or weight dependence should guide researchers in selecting animal species and designing optimal experiments in the application of allometric scaling.

Trevor W Dawson - One of the best experts on this subject based on the ideXlab platform.

  • analytic solution for low frequency electric induction in an equatorially stratified sphere
    Radio Science, 1998
    Co-Authors: Trevor W Dawson
    Abstract:

    This paper considers the analytical solution to the problem of low-frequency induction, by quasi-uniform electric fields, in an equatorially stratified sphere having the particular conductivity distribution σ(ϕ) = σ0e−λcos(pϕ) where p ∈ {1,2} is a periodicity factor, σ0 is a conductivity amplitude factor, and λ > 0 is a dimensionless conductivity Contrast Parameter. This distribution has p conductivity maxima and minima as a function of equatorial angle. The resulting induced electric and current density fields are fully three-dimensional and exhibit interesting, yet physically reasonable, behavior. Most noticeable are the deviations from the straight current paths that would be present in the absence of any conductivity gradient. This solution for electric excitation is supplementary to ones previously published for the quasi-static magnetic excitation and so completes the solution for induction in the sphere by quasi-uniform electromagnetic sources. The nature of the solution is illustrated for the case of both singly and doubly periodic conductivity distributions, for the three canonical source directions.

  • analytic solution for low frequency magnetic induction in an equatorially stratified sphere horizontal excitation
    Radio Science, 1997
    Co-Authors: Trevor W Dawson
    Abstract:

    This paper considers the analytical solution to the problem of low-frequency induction, by quasi-uniform magnetic fields parallel to the equatorial plane, in an equatorially stratified sphere having the particular conductivity distribution σ(ϕ) = σ0e−λ cos(ρϕ), where ρ ∈ {1,2} is a periodicity factor, σ0 is a conductivity amplitude factor, and λ > 0 is a dimensionless conductivity Contrast Parameter. This distribution has ρ conductivity maxima and minima as a function of equatorial angle. The resulting induced electric and current density fields are fully three-dimensional and exhibit interesting, yet physically reasonable, behavior. Most noticeable are current vortices associated with each conductivity maximum. These solutions are supplementary to one previously published for the magnetic source vector perpendicular to the equatorial plane and so complete the solution for induction in the sphere by quasi-uniform magnetic sources. The nature of the solution is illustrated for the case of both singly and doubly periodic conductivity distributions, for two orthogonal source directions.

  • an analytic solution for verification of computer models for low frequency magnetic induction
    Radio Science, 1997
    Co-Authors: Trevor W Dawson, M A Stuchly
    Abstract:

    This paper considers the analytical solution to the problem of low-frequency induction by an applied axial uniform magnetic field, in an equatorially stratified sphere having the conductivity distribution σ (ϕ) = σ0e−λcos(pϕ), where p ∈ {1, 2} is a periodicity factor, λ > 0 is a conductivity Contrast Parameter, σ0 is a conductivity scale factor, and ϕ is the equatorial angle. The resulting induced electric and current density fields are fully three-dimensional. While of interest in its own right, the model should prove useful in the validation of low-frequency electromagnetic computer modeling codes. The development includes a full discussion of the underlying Green's function, which can also be used for modeling induction by alternative excitation fields.

M A Stuchly - One of the best experts on this subject based on the ideXlab platform.

  • an analytic solution for verification of computer models for low frequency magnetic induction
    Radio Science, 1997
    Co-Authors: Trevor W Dawson, M A Stuchly
    Abstract:

    This paper considers the analytical solution to the problem of low-frequency induction by an applied axial uniform magnetic field, in an equatorially stratified sphere having the conductivity distribution σ (ϕ) = σ0e−λcos(pϕ), where p ∈ {1, 2} is a periodicity factor, λ > 0 is a conductivity Contrast Parameter, σ0 is a conductivity scale factor, and ϕ is the equatorial angle. The resulting induced electric and current density fields are fully three-dimensional. While of interest in its own right, the model should prove useful in the validation of low-frequency electromagnetic computer modeling codes. The development includes a full discussion of the underlying Green's function, which can also be used for modeling induction by alternative excitation fields.

Claudiu Filip - One of the best experts on this subject based on the ideXlab platform.

  • spin lattice relaxation in multiple pulse experiments as Contrast Parameter in nmr imaging of solids
    Applied Magnetic Resonance, 1997
    Co-Authors: D E Demco, F Wiegand, C Fulber, Xenia Filip, Claudiu Filip
    Abstract:

    The molecular motion Contrast Parameter for NMR imaging of solids and quasi-solids based on the spin-lattice relaxation (T leff) in multiple-pulse experiments is discussed. For Ostroff-Waugh multiple-pulse sequence theT leff Contrast Parameter is evaluated in slow and fast molecular motion regime and compared with spin-lattice relaxation in the rotating frame Contrast Parameter. It is shown thatT leff is offering a good molecular motion Contrast in NMR imaging of polymer systems. The radio-frequency pulse scheme forT leff-imaging using magic-echo phase-encoding procedure for recording spatial distribution in solids is introduced. A method forT leff-weighted imaging using gradient spin-echo valid for weak dipolar solids is also discussed. The one-dimensional protonT leff image using Ostroff-Waugh pulse sequence in combination with frequency-encoding imaging procedure is presented for a phantom of poly(ethyleneoxide) and poly(methylmethacrylate). The distribution of mechanical stresses in a acrylate film on glass is investigated by protonT leff-imaging. A proton spin-density image weighted byT leff, for a mixture of two elastomers with different crosslink density is also shown.