Prediction of steady-state plasma concentrations of olanzapine in Chinese Han in patients based on a retrospective population pharmacokinetic model

Purpose: To develop robust methods of establishing a population pharmacokinetics (Pop-PK) model of olanzapine, using existing hospital in-patient information, in order to predict the steady-state plasma concentration of olanzapine tablets in Chinese Han inpatients, thus providing guidance for individualized therapy for mental disorders.Methods: A retrospective study analyzing and predicting the steady-state plasma olanzapineconcentration was performed using nonlinear mixed-effect modeling (Phoenix® NLME8). The effects of ten potential covariates, including age, gender, Body Mass Index, fasting lipid, family history, alcohol and smoking status in 107 Chinese Han patients with steady-state plasma olanzapine concentration were collected from the hospital information system (HIS) in Wuhan Mental Health Center from Feb 2017 to Jul 2019.Results: The final model was validated using bootstrap and visual predictive check (VPC) and was found to fit the one-compartment mixed error model. Smoking status was found to be the only factor affecting olanzapine tablets clearance. The standard Pop-PK parameters apparent volume of distribution (VL/F) and clearance (CL/F) were 223 L and 12.4 Lꞏh-1, respectively.Conclusion: The Pop-PK model for olanzapine established with the data from HIS is effective inpredicting the plasma olanzapine tablets concentration of individual Chinese in-patients. This Pop-PK model approach can now be adapted to optimize other antipsychotic drugs.

Observations of a Quickly Flapping Interplanetary Magnetic Reconnection Exhaust

On the basis of the Petschek reconnection model and the characteristics of reconnection, hundreds of reconnection exhausts were reported in the solar wind. Many multi-spacecraft observations also indicated that interplanetary magnetic reconnection is a quasi–steady-state plasma process and the reconnection X-line can extend hundreds of Earth radii. In this study, we report an interplanetary flapping reconnection exhaust observed by Wind on April 1, 2003 at one AU. The magnetic reconnection event has two adjacent accelerated flows. We compared the plasma and magnetic characteristics of the two accelerated flows and found that the second accelerated flow was due to the back-and-forth movement of the reconnection exhaust. Our observations reveal that not all interplanetary reconnections operate in a quasi–steady-state manner; some reconnection current sheets can move rapidly back and forth.

Eigenwave spectra of a solid-state plasma cylinder in a strong longitudinal magnetic field

Subject and Purpose. Eigenwave studies of various bounded structures make a prolific line of investigation in both modern radiophysics and solid-state and functional electronics. Conducting solids demonstrating plasma (semiconductor) properties attract particular attention. Owing to the high conductivity of semiconductors (as it is inversely proportional to the charge carrier effective mass that is smaller than the free electron mass), interest exists in propagation features of slow elliptical-polarization electromagnetic waves – helicons – in magnetized semiconductor waveguides. The present work aims to determine eigenwave spectra of a solid-state plasma cylinder in a strong constant concentric magnetic field. Methods and Methodology. The eigenwave theoretical study of a magnetoplasma cylinder in the free space is conducted in terms of Maxwell's equations. The motion equation of conduction electrons of a solid-state plasma is adopted with quasi-stationarity electromagnetic field conditions satisfied. The collision frequency of majority charge carriers is assumed substantially less than their cyclotron frequency. Results. The dispersion equation of a cylindrical solid-state plasma (semiconductor) waveguide has been obtained. It has been shown that a collisionless magnetoplasma waveguide supports propagation of bulk and surface helicons. The propagation is accompanied by the surface current flowing lengthways cylinder components. Charged particle collisions destroy the surface current and initiate additional (to helicons) H-type hybrid waves such that their phase velocities coincide with phase velocities of the helicons. It has been found that the nonreciprocity effect holds for the waveguide eigenwaves having identical field distribution structures but different azimuthal propagation directions, and it also does as soon as the external magnetic field changes its sense. Conclusion. The research results have deepened our understanding of physical properties of bounded structures with plasma-like filling media. More systematization has been added to the knowledge of eigenwave behavior of these structures in a quasi-stationarity electromagnetic field.