Authors:Binbin Chen, Haiyan Lyu, Xiangzhen Xu, and Chen Wang
Cortisol and cortisone are 2 important glucocorticoids produced in the human hypothalamus–pituitary–adrenal (HPA) axis that respond to stress. An analytical method to determinate cortisol and cortisone in serum and saliva using high-performance liquid chromatography–tandem mass spectrometry following a supported liquid extraction (SLE) was developed. Serum and saliva samples of 0.2 mL were extracted by SLE three times using 0.4 mL of methyl tert-butyl ether each time. The chromatographic separation was obtained on an Agilent Poroshell column using a 0.01% formic acid buffer and acetonitrile (60:40, v/v) as the solvent with a flow rate of 0.3 mL/min. Optimized quantitative mass transitions for cortisol, cortisone, and cortisone d-4 were 363.2/121.0 (m/z), 361.2/163.1 (m/z), and 367.1/270.7 (m/z), respectively. The method validation was achieved according to regulatory guidance. The lower limit of quantification (LLOQ) in serum were 2 ng/mL for cortisol and 1 ng/mL for cortisone, and the LLOQ in saliva were 0.1 ng/mL for cortisol and 0.2 ng/mL for cortisone. The developed method showed convenient and efficient extraction, a lower LLOQ, and a short running time. Modest correlations between serum and saliva cortisol and cortisone concentrations were found. The method was successfully applied in assessing the HPA condition of patients with depressive disorders.
Authors:Jian Zheng, W. Goessler, A. Geiszinger, W. Kosmus, Baolin Chen, Guisun Zhuang, Kai Xu, and Guoping Sui
Earthworms were collected from agricultural fields in Admont, Graz, Piber and Gumpenstein, Austria. Six earthworm samples were investigated with INAA and with ICP-MS in parallel for the element concentrations of As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Pb, Rb, Sb, Se and Zn. With both techniques 14 elements were analysed in a wide concentration range (ng/g to mg/g) GF-AAS and HG-AAS were used for verification of some element concentrations. A comparison of analytical results between INAA and ICP-MS was discussed. In general, good agreement between ICP-MS and INAA was obtained, the relative difference values of most of the elements are within ±20% range, however, a methodical error for the determination of Hg by ICP-MS was found.
The sorption of radiocadmium on Ca-montmorillonite as a function of contact time, pH, ionic strength, foreign ions, humic
acid (HA) and fulvic acid (FA) was studied using batch technique. The results demonstrated that the sorption of Cd(II) was
dependent on ionic strength at pH < 9, and was independent of ionic strength at pH > 9. Outer-sphere surface complexation
and/or ion exchange were the main mechanism of Cd(II) sorption on Ca-montmorillonite at low pH, whereas the sorption at high
pH was mainly dominated via inner-sphere surface complexation. The sorption of Cd(II) on Ca-montmorillonite was dependent
on foreign ions at low pH values, but was independent of foreign ions at high pH values. A positive effect of HA/FA on Cd(II)
sorption was found at low pH values, whereas a negative effect was observed at high pH values. The thermodynamic parameters
(i.e., ΔH0, ΔS0, ΔG0) were calculated from the temperature dependent sorption isotherms, and the results indicated that the sorption process of
Cd(II) on Ca-montmorillonite was spontaneous and endothermic.
A novel adsorbent, TiO2/eggshell composite, was synthesized by sol–gel method, and characterized by XRD and FTIR. The removal of 60Co(II) from aqueous solution by TiO2/eggshell was studied as a function of contact time, pH, ionic strength, foreign ions, humic substances and temperature. The
results indicated that the sorption of 60Co(II) on TiO2/eggshell was strongly dependent on pH and ionic strength. The Langmuir, Freundlich and D-R models were applied to simulate
the sorption of 60Co(II) at temperatures of 303.15, 323.15 and 343.15 K. The thermodynamic parameters (ΔH0, ΔS0, ΔG0) calculated from the temperature dependent sorption isotherms indicated that the sorption process of 60Co(II) on TiO2/eggshell was endothermic and spontaneous. At low pH, the sorption of 60Co(II) was dominated by outer-sphere surface complexation or ion exchange, whereas inner-sphere surface complexation was the
main sorption mechanism at high pH. TiO2/eggshell composites have good potentialities for cost-effective disposal of 60Co(II) bearing wastewaters.
Authors:Youjiu Zhang, Yujie Xu, Ran Zhu, Mingjiang Hu, Jianxiang Li, Yuejin Chen, Daojin Wang, and Wo Fan
This study examined the tissues distribution and pharmacokinetics of rhTNT-IL2, a fusion protein, in rats and macaques after
iv. injection. The rhTNT-IL2 was labeled with 125I. The 125I-rhTNT-IL2 was administered into rats and macaques at a dose of 250 μg·kg−1 and 125 μg·kg−1, respectively. Upon administration, rhTNT-IL2 declined in tri-exponentially with the half-lives of 1.78 h (T1/2α), 25.06 h (T1/2β), 114.19 h (T1/2γ) for rats and 1.87 h (T1/2α), 9.82 h (T1/2β), 43.17 h (T1/2γ) for macaques. The fraction of 125I-rhTNT-IL2 excreted in feces was low (about 1%), while the majority of 125I-rhTN-IL2 was excreted in urine. The tissue distributions showed that the liver, spleen and heart were major organs for deposition
of the fusion protein in rats and macaques in 48-hour post-injection, and the fusion protein could not penetrate through blood
Authors:Longshan Zhao, Qing Li, Yan Cui, Jie Wang, Shanshan Xu, Xiaohui Chen, and Kaishun Bi
The thermal decomposition of a new antibiotic agent, cefuroxime lysine, was investigated by thermogravimetry analysis/derivative thermogravimetry and differential scanning calorimetry (DSC) methods in anoxic and oxidative environments. The influence of heating rates (including 5, 10, 15, and 20 °C/min) on the thermal behavior of cefuroxime lysine was revealed. By the methods of Kissinger and Flynn–Wall–Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.
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.
Authors:Z. Chen, S. Wang, J. Tang, X. Li, C. Liu, X. Xu, and G. Cao
To provide a convenient and facile method to evaluate the radiochemical purity (RCP) of 99mTc-TRODAT-1 in quality control of routine clinical application, a simplified method of single-strip thin layer chromatography
(TLC) was developed and validated by high performance liquid chromatography (HPLC). The RCP data of TLC correlated well with
Authors:Huang Wei, Jie Xiong, Xiaojun Chen, Xiaoling Gao, Yunshu Xu, and Yibei Fu
Polyether-urethane samples were irradiated at the dose range from 10 to 2000 kGy by 2 MeV electron beams. Volatile species
from the polymer degradation were analyzed quantitatively and qualitatively with GC/MS. Thermal properties and micro-phase
separation of the samples were examined by TG and the morphology was studied by TEM and SEM. The results show that the irradiated
polyether-polyurethane evolves CO2, H2, CH4 and C2H6, etc. The thermal stabilities between the hard and soft segments in the irradiated samples are different. At high doses,
the phase separation in the sample is predominant and the hard segment of sample is more stable. The dose rate affects the
soft segment of the irradiated sample much more.