Authors:Jianwei Han, Wenbo Zhu, Ling Yu, Yajun Chen, Gaosong Wu, and Zhibin Wang
A rapid, sensitive and convenient method based on ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous quantification of calycosin-7-O-β-d-glucoside (CCSG), ononin, calycosin, (6aR,11aR)-9,10-dimethoxypterocarpan-3-O-β-d-glucopyanoside (DPPG), and 7,2′-dihydroxy-3′,4′-dimethoxyisoflavan-7-O-β-d-glucopyanoside (DIFG) in rat plasma after oral administration of the methanol extraction from Radix Astragali. Theophylline played the role of internal standard (IS). Preparation of plasma samples by liquid-liquid extraction method with ethyl acetate after precipitation of protein with methanol. The analytes were detected with a triple quadrupole tandem mass spectrometery (MS) in multiple reaction monitoring (MRM) mode and a positive ion electrospray ionization (ESI). The method was validated with the concentration ranges of 1.96–62.69 ng/mL for CCSG, 1.70–54.5 ng/mL for ononin, 1.85–59.06 ng/mL for calycosin, 2.14–137.24 ng/mL for DPPG and1.96–125.25 ng/mL for DIFG, respectively. The method had the lower limit of quantification (LLOQ) with 0.49, 0.21, 0.92, 1.07, and 0.98 ng/mL for CCSG, ononin, calycosin, DPPG and DIFG respectively, and the precision less than 10%. The RSD of the accuracy was in the range of −4.35–8.91%. The results may be helpful to provide more accurate references to clinical application of this herb.
Authors:Ling-Li Li, Guohua Ding, Nan Feng, Ming-Huang Wang, and Yuh-Shan Ho
In this study, we aim to evaluate the global scientific production of stem cell research for the past 16 years and provide
insights into the characteristics of the stem cell research activities and identify patterns, tendencies, or regularities
that may exist in the papers. Data are based on the online version of SCI, Web of Science from 1991 to 2006. Articles referring
to stem cell were assessed by many aspects including exponential fitting the trend of publication outputs during 1991–2006,
distribution of source title, author keyword, and keyword plus analysis. Based on the exponential fitting the yearly publicans
of the last decade, it can also be calculated that, in 2,011, the number of scientific papers on the topic of stem-cell will
be twice of the number of publications in 2006. Synthetically analyzing three kinds of keywords, it can be concluded that
application of stem cell transplantation technology to human disease therapy, especially research related on “embryonic stem
cell” and “mesenchymal stem cell” is the orientation of all the stem cell research in the 21st century. This new bibliometric method can help relevant researchers realize the panorama of global stem cell research, and
establish the further research direction.
Thermotropic phase behaviors of paeonol-encapsulated liposomes containing stigmasterol or cholesterol have been investigated by differential scanning calorimetry. We compared the thermotropic phase behavior of pure dipalmitoylphosphatidylcholine (DPPC) liposomes, sterol/DPPC liposomes, and paeonol/sterol/DPPC liposomes increasing the ratio of paeonol to sterol from 0 to 1, by analyzing the calorimetric parameters of main phase transition of liposomes including phase transition temperature (onset temperature and peak temperature) and phase transition cooperativity. The results showed that paeonol could incorporate into the hydrophobic region of DPPC, thus, decrease phase transition temperature of DPPC. Though stigmasterol interacts with DPPC less favorably than cholesterol, thermotropic phase behavior of paeonol/cholesterol/DPPC liposomes and that of paeonol/stigmasterol/DPPC liposomes are very similar. A phase separation occurred when the molar ratio of paeonol to sterol reached 1:1 in paeonol-encapsulated liposomes, where a paeonol-rich domain coexisted with a sterol-rich domain. The packing order of acyl chains of DPPC in sterol-rich domain is a little higher than that in paeonol-rich domain.
Authors:Haiying Wang, Yucheng Yang, Jianhong Wei, Ling Le, Yang Liu, Chunxu Pan, Pengfei Fang, Rui Xiong, and Jing Shi
Nitrogen-doped titanium dioxide (TiO2) nanotube arrays were synthesized by anodization in ethylene glycol electrolyte and annealing in ammonia at 500 °C. Detailed analysis showed that the nitrogen-doped titania nanotubes were pure anatase of ordered structure, with a crystallite size of 8.5 nm. The doping nitrogen atoms were induced on the interstitial sites and substitutional sites and the ratio of oxygen vacancies increased to 27.15 %, resulting in an add-on peak in the absorption spectrum and extended the absorption from 387 to 618 nm. The photocatalytic activity of the nitrogen-doped TiO2 nanotubes was evaluated by photocatalytic degradation of methyl blue under visible light irradiation. Significant improvement of photocatalytic activity under visible light irradiation was observed. We assumed the nitrogen doping induced the effect produced by nitrogen atoms, Ti3+ cations and oxygen vacancies and the size effect of the TiO2 crystallite should be responsible for the effective photocatalytic activity.
Authors:Yan-Ling Zhao, Jia-Bo Wang, Dan Yan, Li-Mei Shan, Ping Zhang, Rui-Sheng Li, and Xiao-He Xiao
In this study, the activities of four ginsenosides Rc, Re, Rd, and Rf on splenic lymphocytes growth were studied by microcalorimetry. Some qualitative and quantitative information, such as the metabolic power–time curves, growth rate constant k, maximum heat-output power of the exponential phase Pmax and the corresponding appearance peak time tmax, total heat output Qt, and promotion rate Rp of splenic lymphocytes growth affected by the four ginsenosides were calculated. In accordance with thermo-kinetic model, the corresponding quantitative relationships of k, Pmax, tmax, Qt, Rp, and c were established. Also, the median effective concentration (EC50) was obtained by quantitative analysis. Based on both the quantitative quantity–activity relationships (QQAR) and EC50, the sequence of promotion activity was Rc > Re > Rd > Rf. The analysis of structure–activity relationships showed that the number, type, and position of sugar moieties on the gonane steroid nucleus had important influences on the promotion activity of Rc, Re, Rd, and Rf on splenic lymphocytes growth. Microcalorimetry can be used as a useful tool for determining the activity and studying the quantity–activity relationship of drugs on cell.
Splenic lymphocytes play an important role in host acute or chronic diseases. The abnormality of these cells in the spleens of humans might lead to some riskful diseases for human. Hence, in this study, the effects of two ginsenosides Rg1 and Rb1 on splenic lymphocytes growth were studied by microcalorimetry. Some qualitative and quantitative information, such as the metabolic power-time curves, growth rate constant k, maximum heat-output power of the exponential phase Pmax, total heat output Qt of splenic lymphocytes were obtained to present the effects of Rg1 and Rb1 on these cells. The values of k, Pmax, and Qt from the thermogenic growth curves of splenic lymphocytes were found to increase in the presence of Rg1, while the change was adverse for Rb1, illustrating that Rg1 had promotion effect and Rb1 had inhibitory effect on splenic lymphocytes growth and these promotion or inhibitory effects were enhanced with increasing the concentration of the two compounds, respectively. The microcalorimetric results were confirmed by MTT assay for determining the MTT optical density (OD) value and [3H] Thymidine incorporation assay ([3H]-TdR) for determining the count per minute (cpm) value: Rg1 could increase the MTT OD value and the cpm value of [3H]-TdR incorporation into splenic lymphocytes, and these values were increased with increasing the concentration of this compound, while Rb1 had the adverse results. The structure–activity relationships showed that the glucopyranoside and hydroxyl groups at the dammarane-type mother nucleus skeleton might play a crucial role for the opposing effects of the two ginsenosides on splenic lymphocytes. Compared with the other two assay methods, the microcalorimetric method provided more useful and reliable information for quickly and objectively evaluating the effects of drugs or compounds on the living cells, which would be a highly promising analytical tool for the characterization of the biological process and the estimation of the drugs’ efficiency.
Authors:Genquan Yan, Lu Yu, Xu Chen, Triet Tran, Lam Nguyen, Zhijun Wang, and Ling Wang
A rapid and sensitive High-Performance Liquid Chromatography-tandem Mass Spectrometry (HPLC/MS/MS) method for determining apremilast in beagle dog plasma and urine samples was developed and validated using clopidogrel as the internal standard (IS). Apremilast was extracted from the plasma and urine samples by liquid–liquid extraction using methyl tert-butyl ether. Chromatographic separation was performed using a C8 column with gradient elution and a mobile phase containing methanol and 0.1% formic acid. Quantification was achieved in multiple reaction monitoring (MRM) mode with a transition of m/z 461.3→178.2 for apremilast and m/z 322.2→184.1 for clopidogrel (IS). This method was validated regarding its specificity, linearity, precision, accuracy, and stability. The lower limit of quantification (LLOQ) for this method was 5 ng/mL, and the calibration curve was linear over 5–1,000 ng/mL. The intra- and inter-run coefficients of variance (CV) of aprelimast in plasma samples were less than 12.92% and 10.64%, respectively, while in urine samples, the CV were less than 11.84% and 10.20%, respectively. The samples were stable under the tested conditions. This method was successfully applied to a pharmacokinetic study in beagle dogs following oral administration of 10 mg of apremilast.
Authors:Zhang Yan-Ling, Li Xue-Liang, Wang Fang-Ding, Guo Jing-Ru, Tang Pei-Jia, Liu Da-Ming, Cui An-Zhi, and Su Shu-Xin
The fractional cumulative yields (FCY) of133mTe and133gTe in the spontaneous fission of252Cf were measured for the first time by a radiochemical method. The values ofFCY are 0.533±0.014 and 0.291±0.042 for133mTe and133gTe, respectively. The isomeric state to ground state fractional independent yield (FIY) ratio of133Te,R, was found to be 3.5. The root-mean-square angular momentum of the primary fragment corresponding to the fission product133Te, Jr.m.s.=8.8h, was estimated according to a simple one-parameter statistical model. The fractional cumulative yields from this work together with other literature data in the mass region A=131–141 are compared with the normal yields given by the empiricalZp model by Whhl. It suggests that both theN=82 neutrons shell and nucleus pairing effects are not apparent for the spontaneous fission of252Cf.
Authors:Liang Xue, Feng-Qi Zhao, Xiao-Ling Xing, Zhi-Ming Zhou, Kai Wang, Hong-Xu Gao, Jian-Hua Yi, and Rong-Zu Hu
The thermal decomposition behavior of 3,4,5-triamino-1,2,4-triazole dinitramide was measured using a C-500 type Calvet microcalorimeter at four different temperatures under atmospheric pressure. The apparent activation energy and pre-exponential factor of the exothermic decomposition reaction are 165.57 kJ mol−1 and 1018.04s−1, respectively. The critical temperature of thermal explosion is 431.71 K. The entropy of activation (ΔS≠), enthalpy of activation (ΔH≠), and free energy of activation (ΔG≠) are 97.19 J mol−1K−1, 161.90 kJ mol−1, and 118.98 kJ mol−1, respectively. The self-accelerating decomposition temperature (TSADT) is 422.28 K. The specific heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide was determined with a micro-DSC method and a theoretical calculation method. Specific heat capacity (J g−1K−1) equation is Cp = 0.252 + 3.131 × 10−3T (283.1 K < T < 353.2 K). The molar heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide is 264.52 J mol−1 K−1 at 298.15 K. The adiabatic time-to-explosion of 3,4,5-triamino-1,2,4-triazole dinitramide is calculated to be a certain value between 123.36 and 128.56 s.