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Abstract  

The TRPO process has been developed in China for removing transuranium (TRU) elements from the high-level liquid waste (HLLW) since 1980s. In order to meet the requirements of the TRPO process tests, a series of annular centrifugal contactors have also been developed at the Institute of Nuclear and New Energy Technology (INET), Tsinghua University, China. In particular, the Ø10 mm annular centrifugal contactor has been applied successfully in laboratory scale tests of the TRPO process. The Ø70 mm annular centrifugal contactor for semi-industry scale tests of the TRPO process has good performance and two design characteristics, namely a modular design and an overflow structure.

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Abstract  

Non-isothermal crystallization kinetics and subsequent melting behavior for three kinds of ethylene-acrylic acid copolymer (EAA) are investigated via differential scanning calorimetry (DSC). From the Jeziorny method, the crystallization rate of the primary stage is significantly influenced by the competitive mobility of chains. While the crystallization rate in the secondary stage decreases in order of acrylic acid (AA) content in copolymers. Mo’s method can also provide a good fitting. Difference between the Jeziorny method and Mo’s method analysis is because of a higher effect of non-crystallizable chain ends. The effective activation energy is also determined via Kissinger’s method.

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Abstract  

Non-isothermal crystallization kinetics of the ethylene–acrylic acid copolymer (EAA) in diluents during thermally induced phase separation (TIPS) process was investigated via differential scanning calorimetry (DSC). Dioctyl phthalate (DOP), diphenyl ester (DPE), and peanut oil were used as diluents. Kinetic models, such as Jeziorny theory, Ozawa theory, and Mo’s approach, were utilized for description. The effective activation energy of EAA component in mixture was calculated by Friedman’s method. In the results, the Jeziorny theory and Mo’s approach could obtain good linear fitting relationship with the primary crystallization behavior of EAA, but the Ozawa theory failed to get a suitable result. The homogeneous nucleation of EAA proceeded at the end of liquid–liquid phase separation, while the non-isothermal crystallization developed within a solid–liquid phase separation environment. In the mixtures, the molecular weight, polar groups, and conformation of the diluent molecules would affect the nucleation of EAA, and its growth rate. Comparing with the non-isothermal crystallization of neat EAA, EAA in diluents obtained a higher Avrami index n, and comparatively lower crystallization rate. Peanut oil facilitated the homogeneous nucleation of EAA, leading to a higher melting peak temperature of EAA in the subsequent melting endotherms. The largest EAA’s Avrami index obtained in peanut oil also indicated a higher crystal growth dimensional geometry. The crystallization rate and crystallinity of EAA during the non-isothermal process decreased in the sequence: EAA/DPE > EAA/DOP > EAA/peanut oil.

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Abstract  

The sorption of Co(II) on Na-attapulgite as a function of contact time, solid content, pH, ionic strength, foreign ions, fulvic acid (FA) and temperature under ambient conditions was studied. The kinetic of Co(II) sorption on Na-attapulgite was described well by pseudo-second-order model. The sorption of Co(II) on Na-attapulgite was strongly dependent on pH and ionic strength. The sorption of Co(II) was mainly dominated by outer-sphere surface complexation and/or ion exchange at low pH, whereas inner-sphere surface complexation or surface precipitation was the main sorption mechanism at high pH values. The presence of FA did not affect Co(II) sorption obviously at pH <7, and a negative effect was observed at pH >7. The Langmuir and Freundlich models were used to simulate the sorption data at different temperatures, and the results indicated that the Langmuir model simulated the data better than the Freundlich isotherm model. The thermodynamic parameters (∆G°, ∆S°, ∆H°) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on Na-attapulgite was an endothermic and spontaneous process. The results suggest that the attapulgite sample is a suitable material in the preconcentration and solidification of radiocobalt from large volumes of aqueous solutions.

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Acta Chromatographica
Authors:
Peiwu Geng
,
Jing Zhang
,
Bingbao Chen
,
Qianqian Wang
,
Shuanghu Wang
, and
Congcong Wen

Dauricine is the major bioactive component isolated from the roots of Menispermum dauricum D.C., a bisbenzylisoquinoline alkaloid derivative, and has shown multiple pharmacological properties. In this work, a sensitive and selective ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed for determination of dauricine in rat plasma and its application to pharmacokinetic study of dauricine after intravenous and oral administration in rats. After addition of daurisoline as an internal standard (IS), protein precipitation by acetonitrile was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification. Calibration plots were linear throughout the range 2–600 ng mL−1 for dauricine in rat plasma. Relative standard deviation (RSD) of intra-day and inter-day precision was less than 13%. The accuracy of the method was between 95.8% and 105.9%. Matrix effect of dauricine in rat plasma ranged from 88.0% to 90.3%. Mean recoveries of dauricine in rat plasma ranged from 91.5% to 95.1%. The method was successfully applied to pharmacokinetic study of dauricine after intravenous and oral administration in rats. The bioavailability of dauricine was found to be 55.4% for the first time.

Open access

The newly emerged chromatographic fngerprint analysis represents a rational approach assessment of Traditional Chinese Medicine (TCM) and its preparations. In the present paper, a quick and reliable analytical method was developed for the quality assessment of QiYi capsules (QY) using high-performance thin-layer chromatography (HPTLC) with the reference of Tripterygium wilfordii. The unique properties of the HPTLC fngerprint were validated by analyzing 10 batches of QY samples. The 9 common peaks of the HPTLC images of QY and the different RF and peak area ratios of the chemical distribution could directly discern the stability by comparison of 10 samples, and also, the 9 common peaks were selected to evaluate the similarities of QY; the similarities of 10 batches of QY were more than 0.960, which indicated a standardized consistency and reliable quality of QY. Therefore, the newly developed HPTLC fngerprint method provided an easy way for sample characterization and differentiation; it allowed for the quality assessment of QY capsules with the reference of T. wilfordii.

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Abstract  

A new bifunctional extractant named phenyl-N,N-dibutylcarbamoylmethyl sulfoxide (PCMSO) is synthesized and characterized in order to investigate its selectivity and capability in the extraction from acidic nitrate media in nuclear reprocessing. The extraction of uranium (VI) with PCMSO in toluene has been studied at various concentrations of nitric acid, extractant and salting-out agent (LiNO3). The mechanism of extraction is discussed in the light of the results obtained. The extracted species has also been investigated using FT-IR spectrometry. The related thermodynamic functions were calculated. The IR spectral study was also made of the extracted species.

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Studia Scientiarum Mathematicarum Hungarica
Authors:
Jing Quan Chong
,
Xing Chen Huang
,
Tuo Yeong Lee
,
Jing Tao Li
,
Hui Xiang Sim
,
Jing Ren Soh
,
Gabriel Jiaxu Tan
, and
Jay Kin Heng Tai

We prove that

k = 1 n sin  k θ k π θ π o π sin t t d t + 1 2 sin θ + 1 2 1 π 0 π sin t t d t 1 2 sin 2 θ

for all integers n ≥ 1 and ɵ ≤ 8 ≤ π. This result refines inequalities due to Jackson (1911) and Turán (1938).

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Acta Chromatographica
Authors:
Hao-ran Dai
,
Ya-hui Hu
,
Jia-yi Long
,
Ying Xia
,
Hong-li Guo
,
Jing Xu
,
Xuan-sheng Ding
,
Jing Chen
,
Xiao-peng Lu
, and
Feng Chen

Abstract

Perampanel (PER) is the first clinically available selective antagonist of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor approved globally for the treatment of epilepsy. Studies have recently underlined the significant association between dose-exposure-effect-adverse events of PER in patients with epilepsy, so the therapeutic drug monitoring (TDM) of PER is critical in clinical practices, especially for pediatric patients with drug-resistant epilepsy. Due to several limits in previous published analytical methods, herein, we describe the development and validation of a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) method for monitoring PER in human plasma samples. Protein precipitation method by acetonitrile containing PER-d5 as internal standard was applied for the sample clean-up. Formic acid (FA, 0.2 mM) in both aqueous water and acetonitrile were used as the mobile phases and the analyte was separated by an isocratic elution. Qualification and quantification were performed under positive electrospray ionization (ESI) mode using the m/z 350.3 → 219.1 and 355.3 → 220.0 ions pairs transitions for PER and PER-d5, respectively. Potential co-medicated anti-seizure medications (ASMs) have no interference to the analysis. Calibration curves were linear in the concentration range of 1.00–2,000 ng mL−1 for PER. The intra- and inter-batch precision, accuracy, recovery, dilution integrity, and stability of the method were all within the acceptable criteria and no matrix effect or carryover was found. This method was then successfully implemented on the TDM of PER in Chinese children with drug-resistant epilepsy. We firstly confirmed the apparent inter- and intra-individual PER concentration variabilities and potential drug-drug interactions between PER and several concomitant ASMs occurred in Chinese pediatric patients, which were also in line with previous studies in patients of other race.

Open access

Abstract

Letrozole is one of the third generation aromatase inhibitors. It is suitable for the treatment of postmenopausal patients with advanced breast cancer and early treatment of breast cancer. It is necessary to develop a rapid, reliable, selective and sensitive LC–MS/MS assay to determine letrozole in human plasma to evaluate the clinical efficacy and adverse reactions with clinical pharmacokinetic and therapeutic drug monitoring. Separation was carried out on a Kromasil-C18 column using acetonitrile-water (55: 45, v/v) as mobile phase. Detection was carried out by multiple reaction monitoring on a 3200Qtrap mass spectrometry. The method needed one-step protein precipitation procedure only, and the cycle time was 2.5 min allowing 500–550 samples per day. It was linear within 0.30–50.00 ng/mL for plasma with the limit of detection (LOD) of 0.030 ng/mL. The intra- and inter-day RSD were 5.51–8.63%, 2.28–9.95% and the RE was 0.18–1.65%. The recovery rates of letrozole and internal standard for plasma were 89.30–98.55%. Letrozole was stable under all the conditions in the study. The method was sensitive enough to quantitate letrozole over a period of 288 h after giving a single oral dose of 2.5 mg–24 Chinese healthy volunteers. The absorption of letrozole was rapid with small individual difference, the tissue distribution of letrozole was more than that in blood, and the clearance was slow. Letrozole was similar to three-compartment model in vivo. Due to metabolism and excretion, the AUCs of letrozole varied greatly among individuals.

Open access