Authors:L. Xiao, Y. Zhang, Q. Li, Q. Zhang, and K. Wang
Fingernails of pathologically diagnosed normal people, light esophageal epitheliosis patients, severe esophageal epitheliosis patients and esophageal cancer patients were irradiated and their elemental contents were determined by INAA. Multivariate statistical treatment of Ca, Cl, K. Mg, Se and Zn data shows that esophageal cancer patients are distinguishable from non-cancer patients. The accuracy computed by neural networks is greater than 80%.
A reversed-phase high-performance liquid chromatographic method was developed for the first time to simultaneously determine salicin and eight flavonoids in leaves of Salix matsudana, that is salicin, luteolin-7-O-glucoside, myricetin, apigenin-3′-oxyethyl-7-O-glucoside, rutin, quercetin, luteolin, kaempferol and apigenin. The separation of these compounds was achieved on a reversed phase C18 column (250 × 4.6 mm, 5 μm), with linear gradient of methanol in 0.2% phosphoric acid solution with a flow rate of 1.0 mL/min with UV detection at 246 nm. The calibration curves for the determination of all analytes showed good linearity over the investigated ranges (r > 0.999). The % relative standard deviation (% RSD) values were less than 0.34%, and the recoveries were between 95.79% and 99.94%. The values of luteolin-7-O-glucoside, salicin, myricetin, apigenin-3′-oxyethyl-7-O-glucoside, rutin, quercetin, luteolin, kaempferol, and apigenin were 1.0 μg g−1, 20.0 μg g−1, 32.9 μg g−1, 2.0 μg g−1, 29.5 μg g−1, 6.0 μg g−1, 1.0 μg g−1, 3.5 μg g−1, and apigenin was not found in the sample. This developed method can be used for evaluating the quality of different plant materials.
Authors:B. Lin, L. Yang, H. Dai, Q. Hou, and L. Zhang
Soybean oil based polyols (5-OH polyol, 10-OH polyol and 15-OH polyol) were synthetised from epoxidized soybean oil. The melting
peak of polyols and the relationship between melting peak and the number-average functionality of hydroxyl in polyols were
investigated by differential scanning calorimetry (DSC). The thermal decomposition of polyols and some of their thermal properties
by thermogravimetry (TG) and derivative thermogravimetry (DTG) were also studied. The thermal stability of polyols in a nitrogen
atmosphere was very close hence they had a same baseplate of triglyceride for polyols. The extrapolated onset temperature
of polyols in their thermal mass loss, first step had a decreasing order: 5-OH polyol>10-OH polyol>15-OH polyol due to the
difficulty in forming multiple elements ring of them had the same order.
The thermal behavior of polyols under non-isothermal conditions using Friedman’s differential isoconversional method with
different heating rates indicated that the 5-OH polyol had the lowest activation energy in thermal decomposition amongst these
polyols according to the same fractional mass loss because of the weakest intramolecular oligomerization. The 15-OH polyol
was prior to reach the mass loss region because the six-member ring is more stable than the three-member ring from 10-OH polyol
and more easily formed.
Authors:S. Dong, X. Shi, Q. Liu, Z. Zhang, and L. Zhao
A simple hydrolysis method has been developed for determination of phenylethanoid glycosides in Lamiophlomis rotata (L.R.). Different kinds of phenylethanoid glycosides were hydrolyzed in hydrochloric acid solution to produce corresponding phenethyl alcohols and cinnamic acids, mainly containing hydroxytyrosol, homovanillyl alcohol, 3,4-dimethoxyphenethyl alcohol, caffeic acid, fumalic acid and 3,4-dimethoxycinnamic acid. The six analytes could be determined simultaneously by high-performance liquid chromatography (HPLC). The effects of mobile phase, pH and concentration of running buffer, detection wavelength, flow rate and injection volume were also investigated. Under the optimum conditions, the six hydrolyzates could be perfectly separated within 45 min. The response was linear over four orders of magnitude with detection limits (S/N = 3) ranging from 1 × 10−8 to 1.5 × 10−4 mol L−1 for the analytes. The method has been successfully applied to the analysis of real sample Du-Yi-Wei capsule and Qi-Zheng-Yan-Tong patch, with satisfactory results.
Authors:B. Hu, Y. Song, L. Wang, Q. Zhang, J. Li, K. Wei, Y. Chen, and L. Zhang
Electronic stopping power of 19F in Ni, Pd and Gd was measured and compared to Mstar and SRIM calculation as well as experimental results published in literature.
It turns out that the present electronic stopping power agrees reasonably well with them.
Authors:Q. Du, L. Zhang, H. Cui, K. Wang, L. Xiu, and L. Sheng
Cleavage of glucosinolates with myrosinase yields thioglycosidic compounds which have cancer chemoprevention activity. In this paper, glucosinolates in an extract (2.0 g) of broccoli seeds (Brassica oleracea var. italica) were separated by high-speed countercurrent chromatography (HSCCC) with the solvent system n-butanol-acetonitrile-10% ammonium sulfate solution 1:0.5:2.2 (v/v) to yield five glucosinolate compounds after desalting and decolorizing by MCI column chromatography. The five compounds, 7-methylsulfinylheptyl glucosinolate (22.4 mg), 4-pentenyl glucosinolate (33.6 mg), 3-butenyl glucosinolate (24.0 mg), 4-methylsulfinylbutyl glucosinolate (161.4 mg), and 3-methylsulfinylpropyl glucosinolate (29.6 mg), were identified by ESI-MS, 1H NMR and 13C NMR. The purity of the products was >98%, and 7-methylsulfinylheptyl glucosinolate was obtained from broccoli seeds for the first time.
Authors:B. Liu, X. Lv, Z. Tan, Z. Zhang, Q. Shi, L. Yang, J. Xing, L. Sun, and T. Zhang
The molar heat capacity, Cp,m, of a complex of holmium chloride coordinated with L-aspartic acid, Ho(Asp)Cl2·6H2O, was measured from 80 to 397 K with an automated adiabatic calorimeter. The thermodynamic functions HT-H298.15 and ST-S298.15 were derived from 80 to 395 K with temperature interval of 5 K. The thermal stability of the complex was investigated by
differential scanning calorimeter (DSC) and thermogravimetric (TG) technique, and the mechanism of thermal decomposing of
the complex was determined based on the structure and the thermal analysis experiment.
Authors:M.-H. Wang, Z.-C. Tan, Q. Shi, L.-X. Sun, and T. Zhang
heat capacities of 2-benzoylpyridine were measured with an automated adiabatic
calorimeter over the temperature range from 80 to 340 K. The melting point,
molar enthalpy, ΔfusHm,
and entropy, ΔfusSm,
of fusion of this compound were determined to be 316.49±0.04 K, 20.91±0.03
kJ mol–1 and 66.07±0.05 J mol–1
K–1, respectively. The purity of the compound
was calculated to be 99.60 mol% by using the fractional melting technique.
The thermodynamic functions (HT–H298.15) and (ST–S298.15) were calculated based
on the heat capacity measurements in the temperature range of 80–340
K with an interval of 5 K. The thermal properties of the compound were further
investigated by differential scanning calorimetry (DSC). From the DSC curve,
the temperature corresponding to the maximum evaporation rate, the molar enthalpy
and entropy of evaporation were determined to be 556.3±0.1 K, 51.3±0.2
kJ mol–1 and 92.2±0.4 J K–1
mol–1, respectively, under the experimental
Authors:Y. Q. Cheng, Y. X. Zhang, S. D. Qi, H. L. Chen, and X. G. Chen
1,7-Dihydroxy-3,8-dimethoxyxanthone (X1) and 1,8-dihydroxy-3,7-dimethoxyxanthone (X2) are two important xanthones of the Tibetan medicinal plant Gentianopsis paludosa (Hook. f.) Ma. They are very similar in structure, the only difference being exchange of OH and OCH3 at the 7 and 8 positions. By calculations based on the geometry of the molecules using the MM+ force field, the different distances between the hydroxyl groups of the two xanthones were obtained (4.64774 Å for X2 and 7.19412 Å for X1), therefore, the two hydroxyl groups of X1 should freely interact with more water molecules than those of X2 in aqueous solution. In other words, X2 is more hydrophobic than X1. Micellar electrokinetic capillary chromatography (MEKC) was therefore chosen for separation of the compounds. The optimum separation conditions were: 20 mm borate + 20 mm SDS (pH 9.8) as running buffer, 17.5 kV applied potential, and detection wavelength 260 nm. The two xanthones were well separated in 9.0 min, with Gaussian peak shapes. The repeatability of the MEKC method (expressed as RSD) for X1 and X2 was 0.9 and 1.1%, respectively, for migration time, and 3.1 and 1.4% for peak area. The limits of detection (S/N = 3) were 0.41 μg mL−1 for X1 and 0.82 μg mL−1 for X2. The recovery of the MEKC method for the two xanthones was also satisfactory.