Development of an ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry method for determination of xanthopurpurin in rat plasma and its application to pharmacokinetic study

A rapid and sensitive method was developed and validated for the quantitative determination of xanthopurpurin (XPP) in rat plasma using ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry. XPP inhibits IgE production and prevents peanut-induced anaphylaxis. The XPP and emodin (internal standard) were determined in negative ion mode with m/z 239.0350 → 211.0400 and 269.0455 → 241.0507, respectively. The separation process was achieved using an ACQUITY UPLC HSS T₃ column with acetonitrile and 0.1% formic acid in water (85:15). The linear range was 0.5–100 ng/mL, and the correlation coefficient (r²) was > 0.993. The inter-day and intra-day precision was within an acceptable range of 15%. The extraction recovery and matrix effect were 78.9–87.2% and 94.3–98.5%, respectively. Under different conditions, the XPP was stable in the range of 5.6–10.6%. This method was successfully applied to study the pharmacokinetics of XPP with an oral dose of 10.0 mg/kg and intravenous dose of 2.0 mg/kg in rats. The absolute oral bioavailability of XPP was 4.6%.     

A hybrid composite of rhenium complexes covalently grafted on reduced graphene oxide/hydrogenated TiO2 as an efficient catalyst for CO2 reduction under visible light

Research on Chemical Intermediates - The photocatalytic conversion of CO2 to fuels by light is of research interest owing to its relevance to environment and energy concerns. In this work, a hybrid...     

Efficient removal of oil pollutant via simultaneous adsorption and photocatalysis using La–N–TiO2–cellulose/SiO2 difunctional aerogel composite

Research on Chemical Intermediates - Nano-TiO2 photocatalysts doped with La–N(La–N–TiO2) were prepared by solgel method. The La–N–TiO2 was loaded on the cellulose/SiO2...     

Zn–Co Sulfide Microflowers Anchored on Three-Dimensional Graphene: A High-Capacitance and Long-Cycle-Life Electrode for Asymmetric Supercapacitors

Zinc–cobalt double-metal sulfides (ZCS) as Faradic electrode materials with high energy density have great potential for supercapacitors, but their poor transfer efficiency for electrons and ions hinders their electrochemical response. Herein, ZnCo₂(CO₃)_1.5(OH)₃@ZCS microflower hybrid arrays consisting of thin nanolayer petals were anchored on three-dimensional graphene (ZnCo₂(CO₃)_1.5(OH)₃@ZCS/3DG) by a simple hydrothermal method and additional ion-exchange process. A ZnCo₂(CO₃)_1.5(OH)₃@ZCS/3DG electrode delivered high capacitance (2228 F g⁻¹ at 1 A g⁻¹) and long cycling life (85.7 % retention after 17 000 cycles), which are ascribed to the multicomponent structural design. The 3DG conductive substrate improves the electron-transfer dynamics of the electrode material. Meanwhile, the microflowers consisting of thin nanolayer petals could not only provide many active sites for ions to improve the capacitance, but also alleviate the volume expansion to ensure the structural stability. Furthermore, an all-solid-state asymmetric supercapacitor based on a ZnCo₂(CO₃)_1.5(OH)₃@ZCS/3DG electrode achieved a high energy density of 27 W h kg⁻¹ at 528.3 W kg⁻¹ and exhibits exceptional cyclic stability for 23 000 cycles. Its ability to light a blue LED for 9 min verified the feasibility of its application for energy storage devices.     

Redox-Active Two-Dimensional Covalent Organic Frameworks (COFs) for Selective Reductive Separation of Valence-Variable,Redox-Sensitive and Long-Lived Radionuclides

We report the first example of 2D covalent organic framework nanosheets (Redox-COF1) for the selective reduction and in situ loading of valence-variable, redox-sensitive and long-lived radionuclides (abbreviated as VRL nuclides). Compared with sorbents based on chemical adsorption and physical adsorption, the redox adsorption mechanism of Redox-COF1 can effectively reduce the impact of functional group protonation under the usual high-acidity conditions in chemisorption, and raise the adsorption efficiency from the monotonous capture by pores in physisorption. The adsorption selectivity for UO₂²⁺ reaches up to unprecedented ca. 97 % at pH 3, more than for any analogous adsorbing material.     

光纤布拉格光栅传感器应变传递双向耦合分析

粘贴于受弯基体表面的光纤布拉格光栅传感器测量应变与基体真实应变之间存在误差,因此研究光纤布拉格光栅传感器的变形机理、分析测量应变与真实应变之间的关系是目前的研究热点.首先研究光纤布拉格光栅传感器与基体之间的相互作用机理,然后,利用有限元解、实验值和理论解进行对比验证,并分析产生误差的原因.最后,通过参数分析研究弹性模量、厚度、粘结长度等参数对光纤布拉格光栅传感器测量效果的影响.结果表明有限元解、实验值和理论解具有相同的变化趋势,有限元解与理论解的误差在2%以内,测量值与理论解的误差在7%以内.平均应变传递率随着基体弹性模量的增大、粘结长度的增长而逐渐增大,随粘结层弹性模量的减小、粘结层厚度的增大而逐渐减小.该理论对应用于受弯基体应变测量的光纤布拉格光栅传感器的设计具有一定的指导意义.     

Harmonically pump a femtosecond optical parametric oscillator to 1.13 GHz by a femtosecond 515 nm laser

We demonstrate a harmonically pumped femtosecond optical parametric oscillator(OPO)laser using a frequency-doubled mode-locked Yb:KGW laser at a repetition rate of 75.5 MHz as the pump laser.Based on a bismuth borate nonlinear crystal,repetition rates up to 1.13 GHz are realized,which is 15 times that of the pump laser.The signal wavelength is tunable from 700 nm to 887 nm.The maximum power of the signal is 207 m W at the central wavelength of 750 nm and the shortest pulse duration is 117 fs at 780 nm.The beam quality(M^2 factor)in the horizontal and vertical directions of the output beam are 1.077 and 1.141,respectively.     

Dynamic modeling,simulation and design of smart membrane systems driven by soft actuators of multilayer dielectric elastomers

Nonlinear Dynamics - A multilayer membrane element of absolute nodal coordinate formulation is proposed for dynamic modeling of multilayer dielectric elastomer actuators (DEAs). The coupled...     

A new strategy for synthesis of branched cyclic peptide by Asn side-chain hydrazide ligation

Here, we report a new strategy for rapid synthesis of branched peptide by side-chain hydrazide ligation at Asn. The hydrazide was converted to thioester at Asn side chain by NaNO₂ and thiol reagent, and sequential ligation with an N-terminus Cys-peptide efficiently afforded the branched peptide. A branched cyclic peptide was successfully synthesized by side-chain ligation with a two-Cys-peptide and formation of a disulfide bond. This approach provides a new way for expeditious synthesis of branched peptides and facilitates the design of neopeptides as functional bio-mimics.