Synthesis and applications of diethylstilbestrol-based molecularly imprinted polymer-coated hollow fiber tube

A novel molecularly imprinted polymer-coated polypropylene hollow fiber tube (MIP-HFT) was photoinitiated for the copolymerization of diethylstilbestrol (DES) as a template molecule, α-methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinking agent. The characteristics and applications of the MIP-HFT were investigated. In order to compare its characteristics with those of a non-imprinted polymer-immersed hollow fiber tube, the selectivity of the MIP-HFT was investigated using dienestrol and hexestrol as the structural analogues of a DES template, and phenol and methylbenzene were taken as reference compounds. The MIP-HFT was employed in the HPLC analysis of spiked milk samples. The detection limits of the method were found to be in the range 2.5-3.3 μg L⁻¹ for DES, dienestrol and hexestrol and the RSD% were in the range 6.4-8.9. The limits of quantitation were found to be in the range 8.7-9.4 μg L⁻¹ in milk for DES, dienestrol and hexestrol, and their average recoveries were 83.7-90.6% in the spiked milk samples. The experimental results revealed that the MIP-HFT provides a good carrier for the selective adsorption of DES and its chemical structure analogs, and can be used for the preconcentration of these compounds in complicated samples.     

High-resolution intermolecular zero-quantum coherence spectroscopy under inhomogeneous fields with effective solvent suppression

Intermolecular zero-quantum coherences (iZQCs) are not susceptible to magnetic field inhomogeneities significantly larger than the dipolar correlation distance and can be used to obtain 1D high-resolution spectra in an inhomogeneous field. However, with the iZQC methods proposed previously, residual conventional single-quantum coherences (SQCs) originating mainly from solvent resonance result in strong t(1) ridge noises. A modified HOMOGENIZED with an intermolecular double-quantum filter (iDQF), named iDQF-HOMOGENIZED, is presented in this work to suppress the residual conventional SQC signals as well as solvent iZQC signals. The solvent-suppression efficiency of the iDQF-HOMOGENIZED is analyzed and a thorough comparison of the new sequence with several relevant pulse sequences is made. Dramatic resolution enhancement and solvent suppression in the measurements of a piece of grape sarcocarp suggest potential applications of the method in in vivo spectroscopy.     

The impact of vertical π-extension on redox mechanisms of aromatic diimide dyes

The impact of vertical π-extension on redox mechanisms of aromatic diimides in the organic lithium-ion batteries have been carefully studied by a combined experiment and theoretical analyses.     

动物肌肉组织中甾类同化激素多组分残留的液相色谱-质谱检测方法

建立了不同动物肌肉中甾类同化激素(表睾酮、丙酸睾酮、19-去甲基睾酮、甲基睾酮、孕酮、甲羟孕酮、雌二醇、雌三醇、炔雌醇、雌酮)多残留量的LC/MS/MS确证方法。样品加醋酸缓冲溶液均质,加酶溶液酶解后,再加甲醇超声提取,用叔丁基甲醚液-液萃取至少2次,之后经反相固相萃取柱净化,以乙腈-水为流动相,经C18柱分离后进行LC/MS/MS多反应监测模式下的定性及定量分析。其中雄激素,孕激素采用正离子扫描,雌激素则采用负离子扫描。17beta-NT、MTS、ETS、MED、PG、PTS、EST、17beta-ES、EES和ESN的定量检出限为0.5~1.0μg/kg。在1.0μg/kg的定量检出限添加水平,上述10种激素的平均回收率为55%~77%;相对标准偏差为7.1%~35%。可实现样本灵敏、准确的定性定量分析。     

Degradation mechanism of green biopolyester nanocomposites with various cellulose nanocrystal based nanohybrids

Oceans and soils have been contaminated with traditional plastic due to its lack of degradability. Therefore, green biopolymer composites reinforced with cellulose nanocrystal-zinc oxide hybrids (ZnO hybrids) with good biodegradation ability provided a positive impact on reducing environmental challenges. In this work, the effect of various morphologies of ZnO hybrids on the biodegradation ability of poly(butylene adipate-co-terephthalate), PBAT) under seawater, soil burial, and UV aging conditions were investigated. Sheet-like ZnO hybrids (s-ZnO hybrid) efficiently enhanced the mechanical, UV-blocking properties and biodegradation ability of PBAT nanocomposite films. Compared to neat PBAT, the best tensile strength of PBAT nanocomposite with 2 wt% s-ZnO hybrid was increased by 15.1%, meanwhile this nanocomposite films showed the highest biodegradation rate after 80 days of soil degradation and 90 days of seawater degradation. Besides, three possible biodegradation mechanisms of green PBAT nanocomposite films were presented, hinting that such PBAT nanocomposite have great promising packaging applications.

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A simple colorimetric device for rapid detection of Hg(2+) in water

A 'turn-on' fluorescent colorimetric device for Hg(2+) sensing was built using a dual light-emitting diode system. Fluorescence generated from a rhodamine derivative (RHD), an indicator for Hg(2+) sensing, was combined with a background red light, and the complex light was captured by a commercial charge coupled device camera or by the naked eye.     

High-resolution NMR spectroscopy in unstable and inhomogeneous fields via stroboscopic acquisition

In this paper, we demonstrated that despite the insensitivity of intermolecular zero-quantum coherences (iZQCs) to B(0) variations, the influence of unstable fields on the observable single-quantum coherence signals causes strong t(1) noises in the high-resolution iZQC projection spectra. Stroboscopic acquisition was then proposed for noise suppression. The feasibility of the modified sequences with the proposed acquisition scheme was verified by computer simulations and experiments in different unstable fields generated by the Z0 and Z1 coil current oscillations, which mimic the unstable fields of NMR using externally powered magnets and MRS in the presence of physiological motions, respectively.     

常见蔬菜醇提物对黄嘌呤氧化酶的抑制作用

体内尿酸浓度过高将导致高尿酸血症,会引起痛风的发作。黄嘌呤氧化酶既能催化次黄嘌呤生成黄嘌呤,又能催化黄嘌呤生成尿酸。为了提供健康的饮食依据,减少或预防痛风疾病的发生,文中研究了40种常见蔬菜的乙醇提取物对黄嘌呤氧化酶活性的体外抑制作用,结果表明在500mg·L-1用量下,24种蔬菜醇提物对黄嘌呤氧化酶有不同程度抑制作用;醇提物抑制效果最好的4种蔬菜分别是藜蒿、香菜、荷兰豆、红辣椒,抑制率依次为(65.7±0.26)%、(44.2±0.1)%、(40.1±0.12)%、(36.6±0.35)%。体内动物实验表明此4种醇提物在由氧嗪酸钾引起的高尿酸血症模型小鼠体内均具有较强降尿酸作用,并能抑制肝脏黄嘌呤氧化酶的活性,其中藜蒿醇提物效果最显著。     

联吡啶钌-草酸体系电致化学发光猝灭法检测苯胺和联苯胺

利用苯胺和联苯胺对联吡啶钌 草酸体系电致化学发光的强猝灭作用 ,建立了电致化学发光猝灭的流动注射检测苯胺和联苯胺的方法。该方法具有良好的重现性和稳定性。在所选定的实验条件下 ,苯胺和联苯胺的检出限分别为 5 .0× 10 -7mol/L和 2 .0× 10 -7mol/L。对 1.0× 10 -5mol/L的苯胺和联苯胺 ,测定的标准偏差分别为 3%和 2 .5 % (n =6 )。对苯胺和联苯胺对联吡啶钌 草酸体系电致化学发光的猝灭机理进行了初步的探讨。     

Kinetic release of triptolide after injection of renal-targeting 14-succinyl triptolide-lysozyme in a rat kidney study by liquid chromatography/mass spectrometry

Triptolide (TP) is one of the most important biologically active components of the Chinese herb Tripterygium wilfordii Hook f (TWHf). A novel high-performance liquid chromatography/mass spectrometry (LC/MS) method was developed to study the kinetic release of TP after intravenous injection of the newly synthesized 14-succinyl triptolide-lysozyme (TPS-LZM). The method was validated in terms of selectivity, linearity, precision, accuracy, stability, limit of detection (LOD) and limit of quantification (LOQ). The calibration curve was linear over the concentration range 0.5-400.0 ng/g. The mean recovery of triptolide from spiked samples, in a concentration range of 0.5-400.0 ng/g, was 91.84% (RSD = 3.69%, n = 3). The intra- and inter-assay coefficients of variation were less than 6.38%. The method with simple sample pretreatment and being highly specific and precise, can be used for analysis of triptolide release in rat kidney after intravenous injection of renal-targeting TPS-LZM conjugate. The results showed that, as compared with free TP, TPS-LZM could significantly increase the concentration and prolong the action time of TP in the kidney.