Authors:Yalan Liu, Liyong Yuan, Yali Yuan, Jianhui Lan, Zijie Li, Yixiao Feng, Yuliang Zhao, Zhifang Chai, and Weiqun Shi
Uranium is one of the most hazardous heavy metal due to its long half-life radioactivity, high toxicity and mobility as aqueous
uranyl ion (UO22+) under ordinary environmental conditions. Herein, amino functionalized SBA-15 (APSS) was developed as a rapid and efficient
sorbent for removal of U(VI) from the environment. The APSS sample was synthesized by grafting method and was characterized
by SEM, NMR, SAXS, and N2 sorption/desorption isothermal experiments. The sorption of U(VI) by APSS was investigated under different conditions of
pH, contact time, initial U(VI) concentration, ionic strength and solid–liquid ratio. The results show that the sorption of
U(VI) by APSS is strongly dependent on pH but independent of ionic strength and solid–liquid ratios (m/V). The sorption is ultrafast with an equilibrium time of less than 30 min, and the sorption capacity is as large as 409 mg/g
at pH 5.3 ± 0.1. Besides, the U(VI) sorption by APSS from extremely diluted solution and the desorption of U(VI) from APSS
were also studied. It is found that 100 mg of APSS can almost completely remove the U(VI) ions from 4 L aqueous solution with
the U(VI) concentration as low as 4.2 ppb and the sorbed U(VI) can be completely desorbed by 0.1 mol/L nitric acid. The results
strongly reveal the high performance of the APSS material in the removal and preconcentration of U(VI) from the aqueous solution.
Authors:Jian-Hua Yi, Feng-Qi Zhao, Ying-Hui Ren, Si-Yu Xu, Hai-Xia Ma, and Rong-Zu Hu
The thermal decomposition mechanism of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) compound was studied by means of differential
scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG-DTG), and the coupled simultaneous techniques
of in situ thermolysis cell with rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR). The thermal
decomposition mechanism is proposed. The quantum chemical calculation on HNTO was carried out at B3LYP level with 6-31G+(d)
basis set. The results show that HNTO has two exothermic decomposition reaction stages: nitryl group break first away from
HNTO molecule, then hydrazine group break almost simultaneously away with carbonyl group, accompanying azole ring breaking
in the first stage, and the reciprocity of fragments generated from the decomposition reaction is appeared in the second one.
The C–N bond strength sequence in the pentabasic ring (shown in Scheme 1) can be obtained from the quantum chemical calculation as: C3–N4 > N2–C3 > N4–C5 > N1–C5. The weakest bond in NTO− is N7–C3. N11–N4 bond strength is almost equal to N4–C5. The theoretic calculation is in agreement with that of the thermal
Authors:Kang-Zhen Xu, Yong-Shun Chen, Min Wang, Jin-An Luo, Ji-Rong Song, Feng-Qi Zhao, and Rong-Zu Hu
A novel energetic material, 4,5-dihydroxyl-2-(dinitromethylene)-imidazolidine (DDNI), was synthesized by the reaction of FOX-7 and glyoxal in water at 70 °C. Thermal behavior of DDNI was studied with DSC and TG-DTG methods, and presents only an intense exothermic decomposition process. The apparent activation energy and pre-exponential factor of the decomposition reaction were 286.0 kJ mol−1 and 1031.16 s−1, respectively. The critical temperature of thermal explosion of DDNI is 183.78 °C. Specific heat capacity of DDNI was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is 217.76 J mol−1 K−1 at 298.15 K. The adiabatic time-to-explosion was also calculated to be a certain value between 14.54 and 16.34 s. DDNI presents lower thermal stability, for its two ortho-hydroxyl groups, and its thermal decomposition process becomes quite intense.
Acupuncture, the most important nonpharmacological therapy in traditional Chinese medicine, has attracted significant attention since its introduction to the Western world. This study employs bibliometric analysis to examine the profile of publication activity related to it. The data are retrieved from the database of Science Citation Index Expanded during 1980–2009, and 7,592 papers are identified for analysis. This study finds that almost 20 % of papers are published in CAM journals, and the average cited times per acupuncture paper is 8.69. While the most cited article has been cited 2,109 times, however, 38.15 % of total publications have never been cited. Europe has the largest amount of authored papers with high h-index values; the USA has the largest number of publications on and citations of acupuncture based on country distribution, and this has continued as a significant rising trend. The proportion of collaborative papers shows this upward trend on the worldwide scale while the percentage shares of national collaborations are the highest. The USA produces the most international collaborative documents, although South Korea occupies the highest percentage figure for international collaborative papers. International collaborative papers are the most frequently cited. The average number of authors per paper is 3.69 in the top eight countries/regions. Papers contributed by South Korea are authored by the most people. International collaboration papers are authored by more people, except in Taiwan. South Korea's Kyung Hee University is ranked first in terms of number of papers while Harvard University in the USA accounts for the largest proportion of citations. The University of Exeter, Harvard University and Karolinska Institute have the highest h-index values.
Authors:Feng Wu, Xiuli Zhao, Shumin Wang, Hui Zhou, Shaojie Guo, Siyang Ni, Bo Yang, Lihua Zhang, and Xinde Xu
The aim of this study was to develop and validate a HPLC-MS/MS assay to determine the lutein concentration in plasma samples of human and SD rats. Organic solvent was used for lutein extraction. The extract was injected into a HPLC-MS/MS system. Reversed phase chromatography was performed on a C18 column in gradient mode. Lutein and internal standard (phenytoin sodium) were identified in atmospheric pressure chemical ionization mode using ion transitions of m/z 567.5>549.4 and 205.2>110.8, respectively. The lutein quantification assay was linear over concentrations ranging from 4 to 500 ng/mL. The lower limit of quantification was 4 ng/mL with satisfactory precision and accuracy. The assay presented acceptable intra and inter-batch precision (RSD%) and accuracy (RE%) <8.16% in SD rat plasma and <12.80% in human plasma. The extraction recovery ranged from 50.94 to 60.90% in SD rat plasma and 68.73% in human plasma. The matrix effect for lutein was acceptable and had minimal influence on the results. The method was then applied to determine the lutein concentrations in human plasma after a single oral dose of 20mg lutein. The method described is rapid, selective, sensitive and reproducible. This method can be used for both pharmacokinetic studies and therapeutic drug monitoring purposes.
Authors:Kit-leong Cheong, Ding-tao Wu, De-jun Hu, Jing Zhao, Kai-yue Cao, Chun-feng Qiao, Bang-xing Han, and Shao-ping Li
Multiple species of ginseng are well-known Chinese medicinal herbs. The glycome of Panax species has various beneficial effects; however, studies related to their systematic profiling are very limited. Therefore, the systematic profiling of the glycome of Panax species was investigated in this study. The sugars from different locations and different species of Panax (Panax ginseng, Panax quinquefolium, and Panax notoginseng) were prepared by microwave-assisted extraction. Free mono- and oligo-saccharides were identified by high-performance thin-layer chromatography (HPTLC). Furthermore, polysaccharides were compared and characterized by using saccharide mapping based on HPTLC analysis. The results showed that the mono- and oligo-saccharide in Panax species were similar, including the glucan and pectin type of polysaccharides in different locations and different species of Panax, respectively. The data are helpful to better understand the glycome of different species of Panax and may contribute to rational usage of polysaccharides from Panax species.
Authors:L. Feng, H. Xiao, X. He, Z. Li, F. Li, N. Liu, Z. Chai, Y. Zhao, Y. Huang, W. He, and Z. Zhang
To investigate the effects of lanthanum exposure on regional distribution of inorganic elements in rat brain. Wistar rats
were exposed to lanthanum chloride through oral administration at 0, 0.1, 2, and 40 mg/kg concentration for 6 months. The
elements such as Cl, K, Ca, Fe, Cu, and Zn were identified in the brain slices by synchrotron radiation X-ray fluorescence
(SRXRF) analysis. Differences of brain elemental distributions were noticed. Cl, Ca, and Zn were primarily concentrated in
hippocampus of the controls. With the increase of the lanthanum dosage, the Ca and Zn levels significantly decreased, while
the Cu levels significantly elevated in cortex, hippocampus and thalamus. Our results suggest that subchronic lanthanum exposure
in rats appears to change elemental distributions in brain.
Authors:Jian-Hua Yi, Feng-Qi Zhao, Ying-Hui Ren, Bo-Zhou Wang, Cheng Zhou, Xiao-Ning Ren, Si-Yu Xu, Hai-Xia Hao, and Rong-Zu Hu
The high-pressure thermal properties and their correlation with burning rates of the composite modified double base (CMDB) propellants containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz), a substitute of hexogen (RDX), were investigated using the high-pressure differential scanning calorimetry (PDSC). The results show that there is a main exothermal decomposition process with the heating of each propellant. High pressure can restrain the volatilization of NG, accelerate the main decomposition reaction, and make the reaction occur easily. High pressure can change the main decomposition reaction mechanism function and kinetics, and the control process obeys the rule of Avrami–Erofeev equation at high pressure and chemical reaction at normal pressure. However, the mechanism function can not be changed by the ballistic modifier. The correlation between PDSC characteristic values and burning rates was carried out and found that u and keep a good linear relation, ku keeps a similar changing trend with u, and it can be used to study the effect of the ballistic modifier or the other component on the burning rates.
Authors:Liang Xue, Feng-Qi Zhao, Xiao-Ling Xing, Zhi-Ming Zhou, Kai Wang, Hong-Xu Gao, Jian-Hua Yi, Si-Yu Xu, and Rong-Zu Hu
The thermal decomposition behaviors of 1,2,3-triazole nitrate were studied using a Calvet Microcalorimeter at four different heating rates. Its apparent activation energy and pre-exponential factor of exothermic decomposition reaction are 133.77 kJ mol−1 and 1014.58 s−1, respectively. The critical temperature of thermal explosion is 374.97 K. The entropy of activation (ΔS≠), the enthalpy of activation (ΔH≠), and the free energy of activation (ΔG≠) of the decomposition reaction are 23.88 J mol−1 K−1, 130.62 kJ mol−1, and 121.55 kJ mol−1, respectively. The self-accelerating decomposition temperature (TSADT) is 368.65 K. The specific heat capacity was determined by a Micro-DSC method and a theoretical calculation method. Specific heat capacity equation is (283.1 K < T < 353.2 K). The adiabatic time-to-explosion is calculated to be a certain value between 98.82 and 100.00 s. The critical temperature of hot-spot initiation is 637.14 K, and the characteristic drop height of impact sensitivity (H50) is 9.16 cm.
Authors:Kang-Zhen Xu, Xian-Gang Zuo, Hang Zhang, Biao Yan, Jie Huang, Hai-Xia Ma, Bo-Zhou Wang, and Feng-Qi Zhao
A new high-energy organic potassium salt, 1-amino-1-hydrazino-2,2-dinitroethylene potassium salt [K(AHDNE)], was synthesized by reacting of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE) and potassium hydroxide in methanol aqueous solution. The thermal behavior of K(AHDNE) was studied using DSC and TG/DTG methods and can be divided into three obvious exothermic decomposition processes. The decomposition enthalpy, apparent activation energy and pre-exponential factor of the first decomposition process were −2662.5 J g−1, 185.2 kJ mol−1 and 1019.63 s−1, respectively. The critical temperature of thermal explosion of K(AHDNE) is 171.38 °C. The specific heat capacity of K(AHDNE) was determined using a micro-DSC method, and the molar heat capacity is 208.57 J mol−1 K−1 at 298.15 K. Adiabatic time-to-explosion of K(AHDNE) was also calculated. K(AHDNE) presents higher thermal stability than AHDNE.