Search

Polymer dielectrics for energy storage applications usually endure high electric field strength. Adjustment of the composition and structure of the dielectric bulk phase to enhance the dielectric breakdown strength has been widely studied. However, the effect of electrode–dielectric interface on the breakdown strength has received little attention, which greatly hinders further development in this field. In this work, an all-organic double-layer dielectric film consisting of poly(vinylidene fluoride) (PVDF) as the matrix and polymethyl methacrylate (PMMA) as the organic nano-interlayer was prepared. By adjusting the electrode–dielectric interface, remarkably improved electric breakdown strength (767.05 MV m−1) and discharged energy density (19.08 J cm−3) were realized concurrently without sacrificing the charge–discharge efficiency. The experimental results and computational simulations reveal that the surface morphology of dielectrics has a great effect on the electric field distribution at the electrode–dielectric interface, and further affects the leakage current and breakdown strength of the dielectric. The PMMA nano-interlayer modifies the surface defects and increases the Young's modulus at the electrode–dielectric interface, leading to the improvement of insulation performance. These findings offer a new perspective to understand the impact of the electrode–dielectric interface on the polymer dielectric breakdown strength. This work provides a novel paradigm for fabricating polymer dielectrics with high breakdown strength for energy storage.

A novel Zn(II)-based metal–organic framework {[Zn(L)](DMF)3}n (1) was prepared by using Zn(II) ions and bifunctional imidazole carboxylate ligands (5-(1H-imidazol-1-yl)isophthalic acid, H2L). Complex 1 is a fluorescent Zn-MOF sensor with high selectivity and sensitivity for the detection of nitrobenzene. KSV can reach 2.875 × 103 M−1. The protective effect of compound 1 on the hypertension was further explored. Firstly, the RT-PCR was performed to explore the influence of compound on vdr expression in vascular endothelial cells. Then, the ELISA assay was conducted to measure the renin and angiotensin II level in vivo after compound treatment. The results obtained from molecular docking and pose scoring software exhibited a possible binding mode of the compound binding to vitamin D receptor, which might provide potential regulation mechanisms for the compound.

Radix Scutellariae (RS) is a herbal medicine with various pharmacological activities to treat inflammation, respiratory and gastrointestinal infections, etc. In this study, a rapid, sensitive and selective UPLC-ESI-MS/MS method was developed for simultaneous determination of 10 flavonoids - scutellarin, scutellarein, chrysin, wogonin, baicalein, apigenin, wogonoside, oroxylin A-7-O-glucuronide, oroxylin A and baicalin - from RS aqueous extracts in rat plasma with propyl paraben as internal standard (IS). Chromatographic separation was achieved on a C18 column using gradient elution with the mobile phase consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The detection was performed in multiple reaction monitoring mode using electrospray ionization in negative mode. The validated method showed good linearity over a wide concentration range (r >0.9935). The intra- and interday assay variabilities were

Radix Aconiti Lateralis (Fuzi in Chinese, derived from the lateral roots of Aconitum Carmichaeli Debx.) is widely used for the treatment of heart failure, internal cold, arthralgia, diarrhea and edema for thousands of years. It was usually prescribed in combination with Rhizoma Zingiberis (Ganjiang in Chinese, derived from the dry rhizome of Zingiber officinale Rosc.) to decrease toxicity and increase efficacy.In order to investigate the influence of Rhizoma Zingiberis on pharmacokinetics of six Aconitum alkaloids, i.e. aconitine (AC), hypaconitine (HA), mesaconitine (MA), benzoylaconine (BAC), benzoylhypaconine (BHA) and benzoylmesaconine (BMA), in Fuzi-Ganjiang herb couple, the comparative pharmacokinetics of six Aconitum alkaloids after oral administration of Fuzi and Fuzi-Ganjiang aqueous extract was carried out.A sensitive, specific and rapid LC-MS/MS method was developed to determine the six analytes in plasma. Then the rats were randomly divided into two groups and orally administered with Fuzi and Fuzi-Ganjiang aqueous extract. At designated time points after oral administration, the concentrations of the six Aconitum alkaloids in rat plasma were determined, and main pharmacokinetic parameters were investigated using 3P97 (Practical Pharmacokinetics Program Version 1.0).Comparing with Fuzi group, both T1/2 and AUC0-t of AC and HA decreased (P0.05), while T1/2, AUC0-t and Cmax of BAC, BHA increased (P0.05) in Fuzi-Ganjiang group, which indicated that Ganjiang could promote the elimination of AC and HA and enhance the absorption of BAC, BHA and BMA.The differences of pharmacokinetics of Aconitum alkaloids in rat plasma could support those of pharmacologics and toxicity in previous reports between Fuzi and Fuzi-Ganjiang herb couple. The results might be helpful in explaining the mechanism of combination of Fuzi-Ganjiang to decrease toxicity and increase efficacy.

A specific and sensitive high performance liquid chromatography–mass spectrometric (HPLC–MS) method has been developed and validated for simultaneous determination of three anthraquinones of rhein, aloe-emodin and emodin in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang. The analytes were separated on a Kromaisl ® C 18 column within a total running time of 12 min with a mobile phase of methanol:ammonium acetate (3 mM) (75:25, v/v). The calibration curves for all the anthraquinones showed good linearity in the measured range with correlation coefficient ( r ) higher than 0.9978. The precision, accuracy, recovery and stability were deemed acceptable. The method was successfully applied to the comparative pharmacokinetics study of the anthraquinones in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang.

Using reversed-phase high performance liquid chromatography, nine ginsenosides were simultaneously separated on an UltimateC₁₈ column with high-resolution and high purity of each chromatographic peak. Adopting the QAMS quality evaluation model for traditional Chinese medicines, ginsenoside Rb₁ was used as the internal reference substance, and the relative correction factors (RCFs) and the relative retention values (RTRs) of ginsenosides Rg₁, Re, Rf, Rb₁, Rc, Rb₂, Rb₃, Rd and 20 (S)-ginsenoside Rg₃ to ginsenoside Rb₁ were calculated individually. Through a series of methodology evaluations, and positioned by the red ginseng reference chromatograph and RTVs, nine ginsenosides in red ginseng were simultaneously assayed only by quantitative determined ginsenoside Rb₁.

This paper aims to investigate the correlation between the antioxidant activity of Prunella vulgaris and its total phenolic acids content by measuring the antioxidant activity of different sources and different organs of P. vulgaris and the total contents of protocatechuic acid, protocatechuic aldehyde, caffeic acid, salviaflaside and rosmarinic acid in these samples. Using the 50% methanol extract of P. vulgaris samples as the research object, DPPH method and HPLC method were used respectively to determine the antioxidant activities and the total contents of the above-mentioned five analytes in P. vulgaris samples. 0.5 mL of 50% methanol extract of P. vulgaris reacts with 0.1 mmol•L⁻¹ DPPH ethanol solution for 60 min, then the absorbance of the reaction solution was measured at 517 nm, scavenging rate and IC₅₀ values were calculated by the absorbance and the sample concentration for evaluating the antioxidant activity. HPLC analysis was made on a C₁₈ Epic column, with acetonitrile-0.1% formic acid aqueous solution as mobile phase (gradient elution), and the detection wavelength was set at 280 nm. The correlation between the antioxidant capacity of different habitats and different organs of P. vulgaris and the total contents of five kinds of phenolic acids was analyzed by partial least squares method. The reaction dose-response range of 50% methanol extract of P. vulgaris with 0.1 mmol•L⁻¹ DPPH ethanol solution was 0.300-1.65 g•L⁻¹. When the quantities of potocatechuic acid, protocatechuic aldehyde, caffeic acid, salviaflaside and rosmarinic acid were respectively in 0.007 84-0.980, 0.011 5-1.44, 0.008 64-1.08, 0.080 0-1.00 and 0.079 8-0.998 μg range, their quantities were in good linear relationship with the corresponding peak areas. The average recovery of 5 components were 97.76%, 96.88%, 100.3%, 102.1%, 104.5%, with RSD of 1.8%, 1.6%, 1.7%, 1.6% and 1.7%, respectively. In a certain range of crude drug quantity, the antioxidant activity of each organ of P. vulgaris and total phenolic acids content inside has a good linear correlation. Therefore, in certain quality range of crude drug, DPPH bioassay combined with HPLC content determination can be used for the quality control of P. vulgaris, as is a new method for the quality control of P. vulgaris.

Through a series of methodology investigations, we established a new method for simultaneous analysis of epimedins A, B, C, icariin and baohuoside I in Epimedii Folium by using high performance liquid chromatography (HPLC). Meanwhile, using Icariin as an internal reference substance to establish the relative correct factors and relative retention values of Epimedins A, B, C and Baohuoside I to Icariin, then using the quantitative analysis of multi-components by single-marker (QAMS) model, the five analytes can be quantitatively determined in Epimedii Folium and its processed products as well as Kanggu Zengsheng capsule only by measuring the content of icariin in the corresponding samples. All these analysis are completed in the same chromatorgraphic conditions. This paper played the part of demonstration role in the popularization and application of QAMS method established in a single herb to the proprietary Chinese medicines containing this herb.

Three chiral pyridinylmethyl pyrrolidinemethanol derivatives have been synthesized from N -alkylation of ( S )-α,α-diphenyl-2-pyrrolidinemethanol and N -carbonylation of l -proline methyl ester. The catalytic asymmetric borane reduction of prochiral ketones was examined in the presence of chiral oxazaborolidine catalysts prepared in situ from chiral pyridinylmethyl pyrrolidinemethanol derivatives. The corresponding chiral secondary alcohols were obtained with good to excellent enantiomeric excesses (up to 98% ee) using ( S )-2-(diphenylmethanol)-l-(2-pyridylmethyl)pyrrolidine 1 in THF at reflux and moderate to good enantiomeric excesses using C 2 -symmetric compound 2 (up to 86% ee) in THF.

Large-area patterned films of boron nanowires (BNWs) are fabricated at various densities by chemical vapor deposition (CVD). Different widths of unit-cell of Mo masks are used as templates. The widths of unit-cell of Mo masks are 100 μm, 150 μm, and 200 μm, respectively. The distance between unit cells is 50 μm. The BNWs have an average diameter of about 20 nm and lengths of 10 μm–20 μm. High-resolution transmission electron microscopy analysis shows that each nanowire has a β-tetragonal structure with good crystallization. Field emission measurements of the BNW films show that their turn-on electric fields decrease with width of unit-cell increasing.

Large-area boron nanowire (BNW) films were fabricated on the Si(111) substrate by chemical vapor deposition (CVD). The average diameter of the BNWs is about 20 nm, with lengths of 5–10 μm. Then, graphene-capped boron nanowires (GC-BNWs) were obtained by microwave plasma chemical vapor deposition (MPCVD). Characterization by scanning electron microscopy indicates that few-layer graphene covers the surface of the boron nanowires. Field emission measurements of the BNWs and GC-BNW films show that the GC-BNW films have a lower turn-on electric field than the BNW films.

OBJECTIVE To develop a GC-MS method for the determination of methyl nonyl ketone in the volatile oil from the herbs of Houttuynia cordata. METHOD The sample was split in the 240 degrees C injection port, with 20:1 split ratio, and separated on a DB-5 (30 m x 0.25 mm, 0.25 microm film thickness) fused silica column with helium as the carrier gas. The temperature program was as follows: 100 degrees C for 2 min, the 5 degrees C x min(-1) to 150 degrees C, then 15 degrees C x min(-1) to 200 degrees C, and kept for 10 min. The MS transfer line temperature was set to 250 degrees C, the MS source temperature was set to 200 degrees C. The ionization mode was electron ionization (EI) and the selective ion monitor mode was used. RESULT A good linear relationship was constructed over the injection amount range of 5.5-110 ng of methyl nonyl ketone. The average recovery was 98.9%, and RSD was 2. 2%. CONCLUSION The developed method was sensitive, accurate, and can be used for the determination of methyl nonyl ketone in the volatile oil and for the quality control of H. cordata.

Background Invasive pulmonary aspergillosis (IPA) is a rapid, progressive, fatal disease that occurs mostly in immunocompromised patients. Patients with severe liver disease are at a heightened risk for infections. Little is known about the clinical presentation including predisposing factors and treatment of IPA in patients with hepatic failure. Methods Medical records of patients with hepatic failure between November 2005 and February 2007 were reviewed for lung infection. Nine medical records of definitive diagnosis of IPA and three of probable IPA were identified. Results The main predisposing factors were found to be prolonged antibiotic therapy and steroid exposure. Clinical signs and radiological findings were non-specific and atypical. Timely use of caspofungin was found to reduce the mortality due to the disease. Conclusion A high index of suspicion is required for early IPA diagnosis in patients with hepatic failure.