Qualitative analysis of chemical constituents in traditional Chinese medicine analogous formula cheng‐Qi decoctions by liquid chromatography–mass spectrometry

Cheng‐Qi decoctions (CQs), a group of analogous formulas, are well‐known traditional Chinese preparations used as purgative remedies to treat ‘internal heat’‐induced symptoms, which manifest as a bloated and painful abdomen, hard stools, fever and other clinical observations. In this study, HPLC‐ESI‐MS/MS and UPLC‐TOF‐MS were employed for separation and structural identification of constituents in CQs. As a result, a total of 90 compounds, including seven anthraquinones, 39 flavones, 21 glycosides, 11 stilbene glycosides, six organic acids, five coumarins and one lignans, were detected and tentatively identified in CQs extracts. The characterization results shed some light on the scientific foundation for clinical application of the CQ analogous formulas. Our results also indicate that the HPLC‐MS method is useful for the systemic identification of major constituents in traditional Chinese medicine formulas. Copyright © 2015 John Wiley & Sons, Ltd.     

Studying Systematic Errors on Estimation Decision, Detection, and Quantification Limit on Micro-TLC

The decision limit (CCα), capability of detection (CCβ) and quantification limit (QL) are importance performance characteristics in method validation. The TLC-Scanner 3 from Camag provides the possibility to choose the slit dimension of light to determine the peak chromatogram of a substance. The influence of the slit dimension for determination of CCα, CCβ and QL of paracetamol has been carried out. Paracetamol was spotted onto plates of AL-TLC Si G 60 F254 by linomat 4 in the range of 50–400 ng/spot and 10–400 ng/band, then on twin chambers eluted with TAEA (toluene:acetone-ethanol:conc.ammonia, 45 + 45 + 7 + 3 v/v) for 45 mm. Eluted spots were scanned in different slit dimensions at 248 nm. The CCα, CCβ and QL of paracetamol were estimated through the linear regression (LRM) and signal-to-noise (S/N) methods. Slit lengths between 50 and 133 % of the band width of the spots, and with the noise factor of the slit under 2.6, produced good precision measurements of TLC-densitometry between plates, while slit lengths between 50 and 83 % of the band width of the spots introduced a higher sensitivity response of the detector. The estimated CCα, CCβ and QL were determined by how the data were collected, the analytical optical setting, and the usage method for the estimation of both validation parameters.     

Polymeric piezoelectric cantilever and tubular actuators

Electroactive polymers (EAPs) have attracted a great deal of attention in the last decade due to their unique properties that are applicable to many advanced applications. The present work aims to study the materials–property relationship of this class of materials, and thus facilitate the implementation of EAPs in more applications. The present work investigated the feasibility of adapting cantilever and tubular configurations to the polymeric piezoelectric actuators. The polarization and displacement of samples (fabricated from Poly(Vinyldene fluoride‐trifluroethylene) [P(VDF‐TrFE)] thin film) were measured under both dynamic and static driving conditions. The polarization loops for all the samples exhibit little hysteresis under weak field and the polarization changes linearly with voltage for most samples. The frequency‐dependent polarization behavior is consistent with the previous reported work. The displacements for both cantilever and tubular samples are also noted to be in agreement with the theoretical prediction. Significant displacement (1079 µm) was achieved for samples, even under weak field (60 MV/m). In summary, the results have suggested that the relationship between geometric variables and the performance is also applicable to polymeric materials. Thus, the constitutive relationship can also be applied as a guideline for designing and optimizing the polymeric actuators beyond P(VDF‐TrFE) copolymer materials. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis, cure kinetics, and thermal properties of a novel boron–silicon hybrid polymer

A novel boron–silicon hybrid polymer (PASB) was synthesized from polycondensation between phenylboron dichloride and dichloromethylsilane with Grignard reagent. The structure of PASB was characterized using fourier transform infrared spectra, ¹H-NMR, ¹³C-NMR, and gel permeation chromatography. The curing behavior of PASB was investigated by means of non-isothermal differential scanning calorimetry and the kinetic parameters were determined by the Kissinger’s and Ozawa’s methods, respectively. The results showed that both the methods for calculating the activation energy value gave fairly close results of 104.4 and 107.7 kJ mol^?1, respectively. A reasonable curing cycle for the resin system was also established, which suggested that it was reasonable to choose a curing temperature between T _i0 (452.0 K) and T _f0 (554.0 K). These results can provide theoretical guidance reference for determining the curing of the resin system. The thermal stability of cured PASB resin was studied by means of thermogravimetric analysis under nitrogen atmosphere and the temperature of 5 % mass loss (Td₅) was 610.1 °C, the residue at 1,000 °C was 87.8 %, which showed that the cured PASB resin exhibited excellent thermal properties and made it potentially useful as high performance matrix resin and precursor for ceramics.     

Finite Groups with Few TI-Subgroups

A subgroup A of a finite group G is called a TI-subgroup if either A ∩ A ^x  = 1 or A ∩ A ^x  = A holds for all x ∈ G. In this paper, finite group all of whose meta-cyclic subgroups are TI-subgroups are classified completely. In particular, such groups are solvable.