Disposable Parameters Research Articles

Predicting bioequivalence and developing dissolution bioequivalence safe space in vitro for warfarin using a Physiologically-Based pharmacokinetic absorption model

ObjectiveBioequivalence (BE) studies support the approval and clinical use of both new and generic drug products. Narrow therapeutic index (NTI) drugs have relatively high costs and low success rates of BE evaluation clinical trials as high-risk drugs. A physiologically-based pharmacokinetic (PBPK) model can be used to evaluate the BE of two preparations. MethodsThis study inputs the basic physical and chemical property parameters of warfarin sodium available at the present stage into GastroPlus™ software, and combined it with the Advanced Compartmental Absorption and Transit (ACAT™) model built into the software. The PBPK model of Chinese individuals taking 2.5 mg of warfarin sodium orally while fasted condition was developed using the disposal parameters calculated from the clinically measured PK data of the reference preparations. The model was tested using the PK data of other reference preparations and tested preparations from different domestic manufacturers. ResultsThe results revealed that at least 30% of drugs are released in 30 min under a pH of 4.5 condition, and at least 80% are released in 30 min under a pH of 6.8 condition, which can be used as bioequivalent dissolution limits under fasted conditions. The risk of BE failure in the fed condition will be significantly reduced for the clinical study on the BE of warfarin sodium, which is a NTI drug if the fasted condition is bioequivalent. ConclusionThe results revealed that the PBPK models were successfully developed for 2.5 mg of warfarin sodium tablets in Chinese individuals. Developing a PBPK model for NTI drugs based on in vitro dissolution data in software is a promising method for BE evaluation, which can provide great help for developing new drugs and the clinical trial research of BE of generic drugs.

Feasibility of High-Density and Non-Segregable Niobium Ore Tailings

Tailings disposal in the form of diluted slurries has a tendency for particle size segregation, where coarse particles settle near the discharge point, and finer particles are carried by the water flux to more distant regions. This causes a loss of reservoir capacity due to voids between the coarser particles and increased water content in the deposit. This work aimed to evaluate the feasibility of reaching non-segregable high-density slurries with fine tailings from the niobium oreflotation process and measure its disposal parameters. The innovation is to achieve increased solids percentage in the settled deposit and to avoid particle size segregation along the slurry path with niobium tailings. The study involved physical, chemical, and mineralogical characterization and semi-pilot thickening tests to produce enough volume of underflow with different bed heights and solids flux rates. Slump, rheology, and flume tests were performed to evaluate underflow disposal characteristics. The results indicated that the thickener bed height did not significantly influence the underflow solids content, yield stress, or slump. The solids flux rate, on the other side, had a greater influence—the higher it was, the lower the solids content, yield stress, and disposal angle, along with a higher slump. In flume tests, a high density of non-segregable tailings slurry was achieved with 1.96 t/m3, corresponding to an underflow with 66.8% solids, 43.9 Pa of yield stress with 0.5 (t/h)/m2, and 0.5 m of bed height.

Picking Up Quantization Steps for Compressed Image Classification

The sensitivity of deep neural networks to compressed images hinders their usage in many real applications, which means classification networks may fail just after taking a screenshot and saving it as a compressed file. In this paper, we argue that neglected disposable coding parameters stored in compressed files could be picked up to reduce the sensitivity of deep neural networks to compressed images. Specifically, we resort to using one of the representative parameters, quantization steps, to facilitate image classification. Firstly, based on quantization steps, we propose a novel quantization aware confidence (QAC), which is utilized as sample weights to reduce the influence of quantization on network training. Secondly, we utilize quantization steps to alleviate the variance of feature distributions, where a quantization aware batch normalization (QABN) is proposed to replace batch normalization of classification networks. Extensive experiments show that the proposed method significantly improves the performance of classification networks on CIFAR-10, CIFAR-100, and ImageNet. The code is released on https://github.com/LiMaPKU/QSAM.git

An optimal derivative-free King's family for multiple zeros and its dynamics

PurposeThe purpose of this article is to develop and analyze a new derivative-free class of higher-order iterative methods for locating multiple roots numerically.Design/methodology/approachThe scheme is generated by using King-type iterative methods. By employing the Traub-Steffensen technique, the proposed class is designed into the derivative-free family.FindingsThe proposed class requires three functional evaluations at each stage of computation to attain fourth-order convergency. Moreover, it can be observed that the theoretical convergency results of family are symmetrical for particular cases of multiplicity of zeros. This further motivates the authors to present the result in general, which confirms the convergency order of the methods. It is also worth mentioning that the authors can obtain already existing methods as particular cases of the family for some suitable choice of free disposable parameters. Finally, the authors include a wide variety of benchmark problems like van der Waals's equation, Planck's radiation law and clustered root problem. The numerical comparisons are included with several existing algorithms to confirm the applicability and effectiveness of the proposed methods.Originality/valueThe numerical results demonstrate that the proposed scheme performs better than the existing methods in terms of CPU timing and absolute residual errors.

Intrinsic viscuit probability distribution functions for transport coefficients of liquids and solids.

A reformulation of the Green-Kubo expressions for the transport coefficients of liquids in terms of a probability distribution function (PDF) of short trajectory contributions, which were named "viscuits," has been explored in a number of recent publications. The viscuit PDF, P, is asymmetric on the two sides of the distribution. It is shown here using equilibrium 3D and 2D molecular dynamics simulations that the viscuit PDF of a range of simple molecular single component and mixture liquid and solid systems can be expressed in terms of the same intrinsic PDF (P0), which is derived from P with the viscuit normalized by the standard deviation separately on each side of the distribution. P0 is symmetric between the two sides and can be represented for not very small viscuit values by the same gamma distribution formulated in terms of a single disposable parameter. P0 tends to an exponential in the large viscuit wings. Scattergrams of the viscuits and their associated single trajectory correlation functions are shown to distinguish effectively between liquids, solids, and glassy systems. The so-called viscuit square root method for obtaining the transport coefficients is shown to be a useful probe of small and statistically zero self-diffusion coefficients of molecules in the liquid and solid states, respectively. The results of this work suggest that the transport coefficients have a common underlying physical origin, reflecting at a coarse-grained level the traversal statistics of the system through its high-dimensioned potential energy landscape.

Tertiary treatment (Chlorella sp.) of a mixed effluent from two secondary treatments (immobilized recombinant P. pastori and rPOXA 1B concentrate) of coloured laboratory wastewater (CLWW).

Industrial development has increased wastewater (WW) volume; generating contamination and disturbing ecosystems, because of breeching disposal parameters. In this work, Coloured Laboratory Wastewater (CLWW), (1500.00 colour units, CU) was separately submitted to two secondary treatments. For the first one CLWW was treated for three cycles C1, C2 and C3 with P. pastoris X33/pGAPZαA-LaccPost-Stop producing rPOXA 1B laccase, immobilized in calcium alginate beads. For the second-one, rPOXA 1B enzyme concentrate was used (three processes: P1, P2, and P3). Both treatments were carried out in a 15 L reactor with 10 L effective work volume (EWV) with 72h hydraulic retention time. C1, C2, and C3 effluents were flocculated and filtered through quartzite sand, while P1, P2, and P3 effluents were only filtered through quartzite sand. The mixture of secondary effluents was submitted to a tertiary treatment with Chlorella sp. For C1, C2, C3, P1, P2, and P3, CU removal was of 99.16, 99.58, 99.53, 96.72, 97.05 and 96.47%, respectively. Discharge parameters, total organic carbon (TOC), inorganic carbon (IC), chemical oxygen demand (COD) and biological oxygen demand (BOD5) decreased, although they reached different final values. After the tertiary treatment (144h) effluent discharge parameters were reduced to 34 ± 4 CU, TOC to 6.6 ± 0.9mg L-1 and COD to 155 ± 4mg L-1. It was demonstrated that secondary treatments (immobilized recombined cells or recombinant enzyme concentrate) combined with Chlorella sp., (tertiary treatment) attained a considerable removal of discharge parameters, demonstrating a promissory alternative for CLWW sequential treatment.

A BGK model for mixtures of monoatomic and polyatomic gases with discrete internal energy

We generalize the BGK model proposed in Bisi and Cáceres (2016) to a mixture constituted by both monoatomic and polyatomic gas species with each polyatomic one being characterized by its own number of discrete internal energy levels, to model its non-translational degrees of freedom. We prove that all disposable parameters appearing in the Maxwellian attractors may be determined in terms of the actual macroscopic fields in such a way that correct Maxwellian equilibria and collision invariants are preserved, as well as the validity of the H-theorem. Evolution equations for species densities, velocities and temperatures are also derived, and some numerical examples are shown in space homogeneous conditions.

Second virial coefficient of bounded repulsive potentials

Exact series expansion formulas are derived for the second virial coefficient, SVC, of a wide range of purely repulsive bounded potentials. The focus is on the consequences of the functional form, choice of disposable parameters, and temperature on the SVC characteristics. These include compressed and stretched exponential forms, and bounded inverse power (BIP) potentials, which are an extension of the inverse power system. The BIP have a quite different SVC temperature dependence to the exponential cases, characteristics which could be used to represent polymer based dispersed particles which are not accounted for by a gaussian. A new algebraic form of bounded potential is proposed whose SVC at high temperature tends to the Penetrable Sphere, but at low temperature to the BIP class.

Some higher-order iteration functions for solving nonlinear models

In this paper, we present a new efficient sixth-order family of Jarratt type methods for solving scalar equations. Then, we extend this family to the multidimensional case preserving the same order of convergence. We also discuss the theoretical convergence properties of the proposed scheme in the case of scalar as well as multidimensional case. The derivation of these schemes are based on weight function approach and free disposable parameters. We also demonstrate the applicability of them on total six number of problems: first five are real life problems namely, continuous stirred tank reactor (CSTR), chemical engineering, the trajectory of an electron in the air gap between two parallel plates, Hammerstein integration and boundary value problems; last one is the standard academic test problem. In addition, numerical comparisons are made to show the performance of the proposed iterative techniques with the existing techniques of the same order in the scalar as well as multi-dimensional case. Finally on the basis of numerical results, we conclude that our techniques perform better in terms of residual error, error between the two consecutive iterations, asymptotic error constant term and approximated root as compared to the existing ones of same order in scalar as well as multidimensional case.

Mass Entrainment Rate of an Ideal Momentum Turbulent Round Jet

We propose a two-phase-fluid model for a full-cone turbulent round jet that describes its dynamics in a simple but comprehensive manner with only the apex angle of the cone being a disposable parameter. The basic assumptions are that (i) the jet is statistically stationary and that (ii) it can be approximated by a mixture of two fluids with their phases in dynamic equilibrium. To derive the model, we impose conservation of the initial volume and total momentum fluxes. Our model equations admit analytical solutions for the composite density and velocity of the two-phase fluid, both as functions of the distance from the nozzle, from which the dynamic pressure and the mass entrainment rate are calculated. Assuming a far-field approximation, we theoretically derive a constant entrainment rate coefficient solely in terms of the cone angle. Moreover, we carry out experiments for a single-phase turbulent air jet and show that the predictions of our model compare well with this and other experimental data of atomizing liquid jets.

Improved Chebyshev–Halley family of methods with seventh and eighth order of convergence for simple roots

The principle aim of this manuscript is to introduce a new highly efficient improved modification of Chebyshev–Halley family with increasing order of convergence. The idea is based on the schemes proposed by Li et al. (Appl Math Comput 235:221–225, 2014) and Sharma (Appl Math Comput 256:119–124, 2015). The proposed scheme has at least seventh-order of convergence and also posses an optimal eighth-order of convergence for a particular value of the disposable parameter. Each member of the proposed scheme is free from second-order derivative and requires only four functional evaluations (viz. three evaluations of function f and one of first-order derivative $$f'$$ ) per full iteration. A variety of concrete numerical examples demonstrates that our proposed scheme performs better than the existing schemes proposed by Li et al. (Appl Math Comput 235:221–225, 2014) and Sharma (Appl Math Comput 256:119–124, 2015). Dynamical study of our methods also confirms the above conclusions to a great extent. Moreover, the local convergence of these methods is given using hypotheses only on the first derivative and Lipschitz constants.

Optimization of multilayer electromagnetic shields: A genetic algorithm approach

Composites filled with carbon nanoplatelets designed as multi‐layer electromagnetic shields are considered because of their interesting electromagnetic characteristics, such as high electrical conductivity and excellent microwave absorption and shielding behaviour. Layers disposal, their composition and electrical parameters, number and thicknesses are optimized through a real‐coded genetic algorithm to achieve the minimization of the transmitted waves and minimization of reflection loss of the absorbing composites as coating on metal surface. Numerical design of wide frequency band radar absorbing multi‐layer composite structures and highly shielding structures are presented and compared with experimental results.

Lattice dynamical properties of MnTe, HgTe and their mixed semiconductor Mn x Hg1−x Te

In the present paper, the phonon dispersion relations, phonon density of states and Debye characteristics of mixed semiconductor Mn x Hg 1−x Te and the end members MnTe and HgTe using three-body shell model were studied. The model involves 11 disposable parameters and incorporates the effect of the short-range repulsive interactions up to and including the second nearest neighbours, in addition to the long-range Coulombic interactions in the framework of the rigid-shell model with both the ions polarizable. The comparisons of the theoretical results with the available experimental results were in good agreement.

Photon-assisted capacitance–voltage study of organic metal–insulator–semiconductor capacitors

The results are reported of a detailed investigation into the photoinduced changes that occur in the capacitance–voltage (C–V) response of an organic metal–insulator–semiconductor (MIS) capacitor based on the organic semiconductor poly(3-hexylthiophene), P3HT. During the forward voltage sweep, the device is driven into deep depletion but stabilizes at a voltage-independent minimum capacitance, Cmin, whose value depends on photon energy, light intensity and voltage ramp rate. On reversing the voltage sweep, strong hysteresis is observed owing to a positive shift in the flatband voltage, VFB, of the device. A theoretical quasi-static model is developed in which it is assumed that electrons photogenerated in the semiconductor depletion region escape geminate recombination following the Onsager model. These electrons then drift to the P3HT/insulator interface where they become deeply trapped thus effecting a positive shift in VFB. By choosing appropriate values for the only disposable parameter in the model, an excellent fit is obtained to the experimental Cmin, from which we extract values for the zero-field quantum yield of photoelectrons in P3HT that are of similar magnitude, 10−5 to 10−3, to those previously deduced for π-conjugated polymers from photoconduction measurements. From the observed hysteresis we deduce that the interfacial electron trap density probably exceeds 1016m−2. Evidence is presented suggesting that the ratio of free to trapped electrons at the interface depends on the insulator used for fabricating the device.

Lattice dynamics of II–VI mixed semiconductor ZnS 1− xSe x

Lattice dynamical properties of II–VI compounds having zinc-blende structure have been calculated by three-body shell model. This model incorporates the effect of the short-range repulsive interactions up to and including the second nearest neighbours, in addition to the long-range Coulombic interactions in the frame work of the rigid-shell model with both the ions are polarizable. The model involves in total eleven disposable parameters. Using the above proposed model the phonon dispersion relations for mixed II–VI semiconductor ZnS 1− x Se x are plotted. We find an overall good agreement with the experimental results. The application of the present model has been made to calculate the phonon dispersion relations of ZnS, ZnSe and mixed semiconductor ZnS 1− x Se x . The comparison of the theoretical results with the available experimental has been made along high symmetry directions. A reasonably good agreement is observed between theory and experiments.

Global time evolution of an axisymmetric vortex ring at low Reynolds numbers

An initial-value problem of the Navier–Stokes equation is solved, at small Reynolds numbers, for evolution of an axisymmetric vortex ring. The traveling speed is written down in closed form over the whole time range, in terms of the generalized hypergeometric functions, for a vortex ring starting with infinitely thin core. We make a thorough asymptotic analysis of this solution. Three stages are identified, namely, initial, matured, and decaying stages. At the initial stage when the core is very thin, correction terms are found to Saffman’s early-time formula [Stud. Appl. Math. 449, 371 (1970)]. The augmented formula establishes a lower bound on traveling speed of vortex rings starting from delta-function cores and exhibits an excellent agreement with the numerical simulation, at a small Reynolds number, conducted by Stanaway et al. (NASA Technical Memorandum No. 101041, 1988). At the matured and decaying stages, the traveling speed is found to be closely fitted by Saffman’s matured-stage formula, over a very wide time range, by an adjustment of disposable parameters in his formula. The traveling distance as a function of time is also deduced in closed form, and a simple relation of the maximum distance traversed during the whole life, being finite, is found with the viscosity, the initial circulation, and the initial ring radius. The formation number for an optimal vortex ring, estimated based on our solution, compares well with the experiments and numerical simulations.

Qualitative analysis of the generalized Burnett equations and applications to half--space problems

The Generalized Burnett Equations, very recently introduced by Bobylev [3,4], are tested versus Fluid--Dynamic applications, considering the classical steady evaporation/condensation problem. By means of the methods of the qualitative theory of dynamical systems, comparison is made to other kinetic and hydrodynamic models, and indications on an appropriate choice of the disposable parameters are obtained.

Model of Inception and Growth of Damage from Microvoids in Polyethylene-based Materials for HVDC Cables. 1. Theoretical Approach

A comprehensive physical aging and life model is presented for damage inception and growth in polymeric insulation, starting at the level of microscopic cavities, that are known to be one of the most severe factors limiting design electric field and life of cable insulation. Degradation within a polyethylene-based material for HVDC cables is considered as a hot-electron induced bond-breaking process that cumulates with time into the polymer matrix at microvoid-polymer interface, fed by subsequent electron avalanches generated in microvoids. By this way, a conductive pit is formed, that may exceed eventually a critical size for the start-up of a rapid failure mechanism, thereby leading ultimately to electrical breakdown. The model, essentially based on the physical and microstructural characteristics of the insulation, is virtually free from disposable parameters. It is shown to reproduce qualitatively the dependence of insulation time to failure on applied field, temperature and cavity size and to fit quantitatively experimental times-to-failure relevant to PE-based materials in typical working conditions for HVDC cables. The first part of this paper presents the theoretical background and the derivation of model equations, as well as their discussion. The second part deals with parametric investigation and data fitting.

KINEMATIC VISCOSITIES OF POLYETHYLENE GLYCOL + DEXTRAN + WATER SOLUTIONS

ABSTRACT The kinematic viscosities of aqueous polyethylene glycol and dextran and polyethylene glycol + dextran + water were measured at temperatures of 30, 50, and 70°C. Polyethylene glycol with relative molecular masses of 200 and 1000 and dextran samples with nominal molecular masses of 37 500 and 2 000 000 were used. A one-parameter Grunberg-like equation proposed earlier by one of the present authors was used for estimating the values of viscosity of polyethylene glycol + dextran + water. A disposable parameter for the temperature range was calculated as 0.96 and 1.05 for PEG 200 + dextran 37 500 + water and PEG 1000 + dextran 37 500 + water, respectively, and as 2.74 and 2.80 for PEG 200 + dextran 2 000 000 + water, and PEG 1000 + dextran 2 000 000 + water, respectively. In view of our results, the proposed model works well for systems containing polyethylene glycol and dextran with different molecular masses.

Evaluation of viscosities of aqueous two-phase systems containing protein

The dynamic viscosities of aqueous polyethylene glycol, aqueous bovine serum albumin, and polyethylene glycol–bovine serum albumin–water solutions were measured at temperatures of 15, 20, 25, 30 and 35 °C. To estimate the viscosity values of polyethylene glycol–bovine serum albumin–water solutions, a one parameter Grunberg-like model which was satisfactorily used earlier by the present author for polyethylene glycol-dextran–water solutions was employed. The disposable parameter a for our temperature range was estimated as 3.71. The relative errors varying from 0.29 to 18.98 in absolute value indicates that the Grunberg-like model works perfectly for polymer-protein solutions as well.