Simultaneous determination of paeoniflorin from total glucosides of paeony in Sprague–Dawley rats and spontaneously hypertensive rats by high‐performance liquid chromatography–tandem mass spectrometry: in vivo and in vitro studies

Paeoniflorin is a well‐known monoterpene glucoside in the herbal drug that exhibits a number of biological activities. The pharmacokinetic characteristics of paeoniflorin from total glucosides of paeony in spontaneously hypertensive rats (SHR) are still unclear. It is essential to investigate the in vivo and in vitro pharmacokinetic differences of paeoniflorin from total glucosides of paeony in Sprague–Dawley (SD) and SHR. The in vivo pharmacokinetic data were analyzed using DAS 2.0 software and the in vitro metabolic characteristics were measured using rat hepatic microsomes. The concentration of paeoniflorin in biological samples was determined using high‐performance liquid chromatography–electrospray ionization tandem mass spectrometry method, which showed good precision and stability. The plasma concentration–time profiles of paeoniflorin following oral administration of total glucosides of paeony showed a single peak and there were significant differences in the mean values of AUC_(0–t), AUC_(0–∞), CL_z/F and T_max between SD and SHR (p < 0.05). The metabolic rate of paeoniflorin from total glucosides of paeony was slower in SHR than in SD rats (p < 0.05). The results might be useful in further applications of paeoniflorin and total glucosides of paeony. Copyright © 2016 John Wiley & Sons, Ltd.     

Preparation of hydrophilic poly(vinylidene fluoride) membrane by in-situ grafting of N-vinyl pyrrolidone via a reactive vapor induced phase separation procedure

Increasing hydrophilicity of hydrophobic membrane is one of the strategies to improve its antifouling performance. Herein we report a procedure of reactive-vapor induced phase separation to prepare an N-vinyl pyrrolidone (NVP) modified poly(vinylidene fluoride) (PVDF) membrane to improve its hydrophilicity. PVDF solution containing NVP monomer was cast in ammonia water vapor atmosphere to prepare the modified membrane. During the process, PVDF was dehydrofluorinated by the reactive vapor of ammonia water to generate double bond of FC═CH, and then NVP was grafted. The degree of grafting modification and the microstructure evolution of the membrane were studied by adjusting the amount of NVP addition. A possible mechanism of membrane formation from crystallization gelling to non-crystallization gelling has been proposed to understand the morphology change from nodular sphere to bi-continuous microstructure with fibril matrix. It has been found that rising the degree of modification has changed the polymorph of PVDF from β to α crystalline phase, as well as turned the hydrophobic PVDF membrane into hydrophilic. Moreover, the modified membrane displayed obvious reduction in bovine serum albumin adsorption, suggesting improvement in anti-fouling performance. Therefore, our work provides an easy strategy to prepare hydrophilic PVDF membrane, which may have promising potential applications.     

Pharmacokinetic analysis of plasma bicyclol by liquid chromatography–tandem mass spectrometry

Bicyclol is a synthetic drug widely used to treat chronic hepatitis B. This study aimed to develop a selective, sensitive and high‐throughput liquid chromatography–tandem mass spectrometric method for the detection of bicyclol in human plasma. Bicyclol was detected using a multiple reaction monitoring mode, with ammonium adduct ions (m/z 408.2) as the precursor ion and the [M‐CH₃]⁺ ion (m/z 373.1) subjected to demethylation as the product ion. Chromatographic separation was achieved using a Zobax Eclipse XDB‐C₁₈ column with a gradient elution and a mobile phase of 2 mm ammonium formate and acetonitrile. Bicyclol was extracted from plasma matrix by precipitation. A linear detection response was obtained for bicyclol ranging from 0.500 to 240 ng/mL, and the lower limit of quantification was 0.500 ng/mL. The intra‐ and inter‐day precisions were all ≤7.4%, and the accuracies were within ±6.0%. The extraction recovery was >95.9%, and the matrix effects were between 96.0% and 108%. Bicyclol was found to be unstable in human plasma at room temperature, but the degradation was minimized by conducting sample collection and preparation in an ice bath. The validated method was successfully applied to investigate the pharmacokinetics of bicyclol tablets in six healthy Chinese volunteers.     

Directed partial orders on the field of generalized complex numbers with $$1\not >0$$ 1 ≯ 0

Positivity - Let F be a non-archimedean o-field and $$C=F(i)$$ be the field of generalized complex numbers over F. In Ma et al. (Order 35:461–466, 2018), all directed partial orders on C with...     

High‐TC Ferromagnetic Semiconductor‐Like Behavior and Unusual Electrical Properties in Compounds with a 2×2×2 Superstructure of the Half‐Heusler Phase

Heusler phases, including the full‐ and half‐Heusler families, represent an outstanding class of multifunctional materials on account of their great tunability in compositions, valence electron counts (VEC), and properties. Here we demonstrate a systematic design of a series of new compounds with a 2×2×2 superstructure of the half‐Heusler unit cell in X–Y–Z (X=Fe, Ru, Co, Rh, Ir; Y=Zn, Mn; Z=Sn, Sb) systems. Their structures were solved by using both powder and single‐crystal X‐ray diffraction, and also directly observed by using high‐angle annular dark‐field imaging in a scanning transmission electron microscope (HAADF‐STEM). The VEC values of these new compounds span a wide and continuous range comparable to those for the full‐ and half‐Heusler families, thereby implying tunability in compositions and physical properties in the superstructure. In fact, we observed abnormal electrical properties and a ferromagnetic semiconductor‐like behavior with a high and tunable Curie temperature in these superstructures.     

Development and validation of an LC/MS/MS method for simultaneous determination of shionone and epi‐friedelinol in rat plasma for pharmacokinetic study after oral administration of Aster tataricus extract

A rapid and sensitive liquid chromatography tandem mass spectrometry (LC/MS/MS) method was developed and validated using spinasterol as the internal standard (IS) for the simultaneous determination of shionone and epi‐friedelinol in rat plasma. Plasma samples were pretreated using liquid–liquid extraction with ethyl ether. Chromatographic separation was achieved on a C₁₈ column (100 × 2.1 mm, 5 μm) with an isocratic elution consisting of acetonitrile–0.1% formic acid water (75:25, v/v) at a flow rate of 0.30 mL/min. Detection was performed under the selected reaction monitoring scan using an electrospray ionization in the positive ion mode. The mass transitions were as follows: m/z 427.4 → 95.1 for shionone, m/z 411.4 → 205.2 for epi‐friedelinol and m/z 395.3 → 105.2 for IS. All calibration curves exhibited good linearity (r > 0.995) over the concentration range for both components. The intra‐ and inter‐day precisions at three QC and lower limit of quantitation levels were both <10.21% in terms of relative standard deviation, and the accuracy ranged from ?7.13 to 8.02% in terms of relative error. The extraction recoveries of the compounds ranged from 82.07 to 89.81%. The developed method was successfully applied to the pharmacokinetic study of shionone and epi‐friedelinol after oral administration of Aster tataricus extract to rats. Copyright © 2015 John Wiley & Sons, Ltd.     

The Synthesis and Biological Activities of [5-(4-Substituted Phenylsulfinyl/Sulfonyl)-1,3-Dimethyl-1H-Pyrazol-4-Yl]-Arylmethanones

Abstract

A novel series of pyrazole derivatives containing substituted phenylsulfinyl/sulfonyl group have been synthesized via the oxidation of intermediate pyrazole sulfoether with H₂O₂ in acetic acid. The novel compounds were characterized by melting point, ¹H NMR, FT-IR, MS, and elemental analysis or HRMS. The biological activity results showed that most of the title compounds exhibit significant fungicidal activities against Alternaria solani Sorauer, Phytophthora capsici, and Corynespora cassiicola.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Construction of Dual Pore 3-D Digital Cores with a Hybrid Method Combined with Physical Experiment Method and Numerical Reconstruction Method

In order to further improve the accuracy of digital core modeling, a new hybrid method was proposed to construct the dual pore 3-D digital core with high precision. First of all, 3-D macro-pore digital cores were constructed by micro-CT. Secondly, based on the high-resolution 2-D scanning electron microscopy images of rock cores, micro-pore digital cores were constructed by simulated annealing method. And then, a superposition method was used to construct the digital core which could describe different pore characteristics. Finally, pore structures of digital cores were compared, and lattice Boltzmann method was used to analyze the percolation properties. The results show that the carbonate dual pore digital core constructed by the new hybrid method has a high accuracy, which can capture the pore properties of both macro-pore and micro-pore, and whose permeability simulation results are in good agreement with the experimental measurements. In addition, the new hybrid method is not only accurate and reliable, but also high efficient and economic, and can be applied to all kinds of reservoir modeling.