Faddeev–Jackiw canonical path integral quantization for a general scenario,its proper vertices and generating functionals

We generalize the Faddeev–Jackiw canonical path integral quantization for the scenario of a Jacobian with J=1 to that for the general scenario of non-unit Jacobian, give the representation of the quantum transition amplitude with symplectic variables and obtain the generating functionals of the Green function and connected Green function. We deduce the unified expression of the symplectic field variable functions in terms of the Green function or the connected Green function with external sources. Furthermore, we generally get generating functionals of the general proper vertices of any n-points cases under the conditions of considering and not considering Grassmann variables, respectively; they are regular and are the simplest forms relative to the usual field theory.     

Direct infusion electrospray ionization–ion mobility–mass spectrometry for comparative profiling of fatty acids based on stable isotope labeling

A rapid method for fatty acids (FAs) comparative profiling based on carboxyl-specific stable isotope labeling (SIL) and direct infusion electrospray ionization–ion mobility–mass spectrometry (ESI–IM–MS) is established. The design of the method takes advantage of the three-dimensional characteristics of IM–MS including drift time, m/z and ion intensity, for comparison of d0-/d6-2,4-dimethoxy-6-piperazin-1-yl pyrimidine (DMPP)-labeled FAs. In particular, without chromatographic separation, the method allowed direct FAs profiling in complex samples due to the advantageous priority of DMPP in signal enhancement as well as the extra resolution that IM–MS offered. Additionally, the d0-/d6-DMPP-labeled FAs showed expected features, including very similar drift times, 6 Da mass deviations, specific reporter ions, similar MS responses, and adherence to the drift time rule regarding the influence of carbon chain length and unsaturation on relative drift times. Therefore, the introduction of isotope analogs minimized the matrix effect and variations in quantification and ensured accurate identification of non-targeted FAs by those typical features. Peak intensity ratios between d0-/d6-DMPP-labeled ions were subsequently used in relative quantification for the detected FAs. The established strategy has been applied successfully in the rapid profiling of trace free FAs between normal and cancerous human thyroid tissues. Sixteen free FAs were found with the increased level with a statistically significant difference (p < 0.05) compared to the normal tissue samples. The integrated SIL technique and ESI–IM–MS are expected to serve as an alternative tool for high-throughput analysis of FAs in complex samples.     

Pressure-dependent terahertz optical characterization of heptafluoropropane

Heptafluoropropane(HFP), as the best alternative to halon fire-suppression agents, is now a widely used fire extinguishing agent. The current studies of HFP, concentrating on the extinguishing mechanisms of flames and decomposition products, in general deal with the destructive and high temperature cases. In this paper, terahertz time-domain spectra are used to characterize HFP at different pressures. Optical parameters of HFP, such as absorption coefficient, refractive index, and relative permittivity, and their relationship with concentration of samples, are discussed. The absorption peak of HFP at 0.3 THz depends strongly on the applied pressure, and the corresponding parameters increase almost linearly with increasing HFP concentration. The present study lays a foundation for future extensive applications.     

Hepatic,gastric and intestinal first‐pass effects of vitexin‐2′′‐O‐rhamnoside in rats by ultra‐high‐performance liquid chromatography

Previous research in our laboratory found that the absolute bioavailability of vitexin‐2′′‐O‐rhamnoside (VR) was quite low at 4.89%. A rapid and sensitive UHPLC method using hesperidin as an internal standard was therefore developed and validated to investigate the reasons for this by determining VR in rat plasma after administering intravenously, intraportally (5 mg/kg), intraduodenally and intragastrically (40 mg/kg) to the rat model of the hepatic, gastric and intestinal first‐pass effects. As only a high intestinal first‐pass effect of VR was found, that is, there existed a low bioavailability of VR (2.40%), inhibitors of P‐glycoprotein (P‐gp) and cytochrome P450 3A (CYP3A), including verapamil, cyclosporin A and midazolam, and absorption enhancers, including bile salts and borneol, combined with VR, were instilled into duodenum to evaluate the effects on bioavailability of VR. The results demonstrated that area under the concentration–time curve (AUC) values of VR slightly increased after administration of verapamil, cyclosporin A and midazolam, indicating that CYP3A and P‐gp do not play an important role in the first‐pass effect in the intestine. AUC values of VR significantly increased after administering bile salts or borneol, indicating that the low bioavailability of VR was mainly related to its poor absorption in the intestine. Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous determination and pharmacokinetics of four triterpenoids by ultra high performance liquid chromatography with tandem mass spectrometry after the oral administration of Acanthopanax sessiliflorus (Rupr. et Maxim) Seem extract

A specific, simple, and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method utilizing the Triple Quad system has been developed and validated for the simultaneous determination and pharmacokinetic study of four triterpenoid components of Acanthopanax sessiliflorus in rat plasma. The components are 22‐α‐hydroxychiisanogenin, chiisanogenin, (1R,11α)1,4‐epoxy‐11‐hrdroxy‐3,4‐secolupane‐20(30)‐ene‐3,28‐dioic acid, and 22‐α‐hydroxychiisanoside. Sample preparation involved a liquid–liquid extraction of the analytes with ethyl acetate. Chromatographic separation was accomplished using an Agilent SB‐C₁₈ column (1.8 μm, 2.1 mm × 50 mm) with 2.0 min isocratic elution. The compounds were detected with a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode and an ESI source in negative mode. The method was linear for all analytes over the investigated range, with all determined correlation coefficients exceeding 0.9906. The limit of quantification of each analyte was lower than 1 ng/mL. The intraday and interday precisions were less than 14.9%, and the accuracy ranged from –10.2 to 11.8%. The mean recoveries of the analytes were higher than 80.0%, and the matrix effects were between 100.4 and 107.1%. These results may contribute to determining the mechanism of action and guiding the clinical application of Acanthopanax sessiliflorus.     

Ethanol-assisted ablation of silicon and germanium by temporally shaped femtosecond pulses

A surprising phenomenon can be discovered by using femtosecond double-pulse ablation of silicon and germanium in ethanol. The ablation areas present an oscillation increase phenomenon when the pulse delay increases from 200 fs to 1 ps in the fluence range of 0.5–0.6 J∕cm2. In contrast, the ablation areas exhibit an oscillation decrease phenomenon as the pulse delay increases when the laser fluence F 0.5 J∕cm2, which is consistent with the results of the experiment in air. It is considered that the adjustment of the photon–electron coupling efficiency by pulse train technology plays an important role in the ablation process.     

Facile and robust strategy to antireflective photo-curing coating through self-wrinkling

We reported a facile and bio-inspired strategy for obtaining antireflective(AR) coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-crosslinking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5%～8%, with an efficiency antireflection of 4%～7% compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4%～8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern.Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle