Authors:G. Zhang, X. Li, S. Tian, J. Li, J. Wang, X. Lou, and Q. Cheng
The stability of β-cyclodextrinethyl benzoate6H2O(β-CDC6H5COOC2H56H2O) was investigated by TG and DSC. The mass loss takes place in three stages: the dehydration occurs at 50-120C; the dissociation
of β-CDC6H5COOC2H5occurs at 200-260C; the decomposition of β-CD begins at 280C. The kinetics of the dissociation of β-CDC6H5COOC2H5in a dry nitrogen flow was studied by means of thermogravimetry both at constant temperature and linearly increasing temperature.
The results show that the dissociation of β-CDC6H5COOC2H5is dominated by a three-dimensional diffusion process (D3). The activation energy E is 116.19 kJ mol-1and the pre-exponential factor A 6.5358109min-1.
Cyclodextrin is able to form inclusion complexes with a great variety of guest molecules, and the studies focus on the energy
of binding between cyclodextrin and the guest molecule. In this paper, the β-cyclodextrinethyl benzoate inclusion complex
was studied by fluorescence spectrophotometry and infrared absorption spectroscopy, and the results show that the stable energy
of inclusion complexes of β-CD with weakly polar guest molecules consists mainly of van der Waals interaction.
Authors:X. Zheng, Y. Yu, G. Xiao, Y. Xu, J. Wu, D. Tang, Y. Cheng, and Y. Zhang
Changes in microbial population, pH, sugar, organic acid, anthocyanins, total soluble phenolics, and anti-glucosidase contents were measured during fermentation of mulberry juice at 30 °C by probiotic Leuconostoc mesenteroides showing rapid growth after an approximately 1-day lag phase and reaching a maximum of 8.6 log CFU ml−1 after 4 d. During the rapid growth phase, the main mulberry juice sugars, glucose and fructose, were largely consumed, and the acidic metabolites, lactic acid and acetic acid, were produced accordingly. A slow decrease in the concentration of the main organic acid, citric acid, was also observed during fermentation. After 4 d fermentation, anthocyanin content showed a 44.4% reduction, but the total amount of soluble phenolics and α-glucosidase inhibitory activity showed no significant changes (P>0.05). This suggests that L. mesenteroides fermentation of mulberry juice is a good strategy to enhance its probiotic value and to decrease the sugar content without changing the anti-glucosidase activity, which is required to reduce postprandial rise in blood glucose.
Authors:D. Jiang, X. Li, Z. Qiu, R. Lu, Y. Li, and G. Zhang
Nuclear microprobe was used to measure single aerosol particles (SAPs) indoors from Shanghai. Every particle is characterized
with its micro-PIXE spectrum, which can be considered as the fingerprint of the SAPs. The pattern recognition technique (PR)
was applied to trace the SAPs back to their source. Results of five monitor homes at different locations in Shanghai show
that most of the measured indoor aerosol particles are derived from soil dust, cement dust, vehicle exhaust, coal boilers
and steel mill dust.
Authors:J.-H. Hong, J. Min, G.-H. Guo, and K.-L. Zhang
The Eu tris(dibenzoylmethanato)phenanthroline
complex doped xerogel has been synthesized by a catalyst-free sol-gel roure.
The non-isothermal kinetic analysis is calculated by Friedman isoconversional
method and multivariate non-linear regression method. The overall decomposition
process below 600C is fitted by an Fn model (n
order reaction), corresponding to the dehydration of the matrix, and a two-step
consecutive reaction of Cn model (n order
autocatalytic reaction), corresponding to the decomposition of organic complex.
Correlation coefficient is 0.99986. The lifetime values of xerogel, defined
as the 5% decomposition of europium organic complex, indicate that the xerogel
can find application at near room temperature.
Authors:Xiufang Zhang, G. Yang, Y. Liu, W. Yu, K. Pan, Ruixiang Li, and M. Zhu
Prorocentrum donghaiense caused large-scale red tides off Chinese coast in recent years. Expressed sequence tag (EST) analysis was carried out for this dinoflagellate in order to identify the genes involved in its proliferation and death. A cDNA library was constructed for P. donghaiense at late exponential growth phase, and 308 groups of EST were generated, which include 36 contigs and 272 singletons. Among 22 groups showed homologies with known genes, 2 matched significantly with caspase and proliferating cell nuclear antigen. Caspase and proliferating cell nuclear antigen are 2 key proteins involved in programmed cell death. Their identification evidenced preliminarily the induction of PCD in aging P. donghaiense. The identified included also calmodulin and protein phosphatase, two proteins involved in diverse cell processes including PCD by binding to or modifying others.
Authors:L.-M. Zhang, W.-G. Xie, T.-T. Wen, and X. Zhao
The thermal behavior of five free anthraquinones (chrysophanol, emodin, physcion, aloe-emodin, and rhein) from rhubarb had
been investigated using TG, DTG and DTA technique. The results show that all the free anthraquinones have the similar TG and
DTG curve shapes, however, due to the substituted groups attached on the skeleton of 1,8-dihydroxy anthraquinone are different,
every anthraquinone has different mass loss features. Moreover, all the DTA curves of these free anthraquinones have two obviously
characteristic peaks, but with special curvilinear types, peak location and peak values. Therefore, thermal analysis (TA)
characteristics of anthraquinones above mentioned could be established, and it is possible to easily distinguish these anthraquinones
by using TA technique.
Authors:J. Zhou, Z. Yang, J. Feng, X. Zhang, G. Li, and Z. Ren
plays an important role in wheat improvement. Here we report a new triticale, named Fenzhi-1, derived from the wide cross MY11
after the in vitro rye pollen has been irradiated by He-Ne laser. Morphologically, Fenzhi-1 is characterized by branched-spikes. Genetically, Fenzhi-1 displays stable fertility and immunity to wheat powdery mildew and stripe rust. In situ hybridization (FISH) and seed storage protein electrophoresis revealed that Fenzhi-1 is a new primary hexaploid triticale (AABBRR). The present study not only provides a new method to synthesize an artificial species, but also shows that Fenzhi-1 could be a valuable source for wheat improvement.
Authors:J. Li, W. Dai, G. Xiao, H. Wang, Z. Zhang, and T. Wu
99Tc is an important radionuclides related to repository safety assessment. The mobility pertechnetate (TcO4−) can be reduced to immobility technetium(IV) hydrous oxides (TcO2·nH2O) by Fe(II)-bearing minerals. In China, Gaomiaozi (GMZ) bentonite is regarded as the favorable candidate backfilling material
for the HLW repository, which is contained some FeO. The diffusion behavior of 99Tc was investigated in GMZ bentonite by through- and out-diffusion methods. The effective diffusion coefficient (De), the accessible porosity (εacc), apparent diffusion coefficient (Da) and distribution coefficient (Kd) were decreased with the increasing of dry density. The De values were (2.8 ± 0.2) × 10−11 m2/s and (3.5 ± 0.2) × 10−12 m2/s at dry density of 1,600 and 1,800 kg/m3, respectively. It was indicated that the dominating species was TcO4− during the diffusion processing. While, out-diffusion results showed that part of TcO4− may be reduced by Fe(II). The relationship of De and εacc could be described by Archie’s law with exponent n = 2.4 for 99Tc diffusion in GMZ bentonite. Furthermore, the relationship between Da and dry density (ρ) was exponential.
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.
Authors:W. Zhou, X. Y. Zhang, Y. P. Lv, X. D. Liu, C. Xu, and G. L. Duan
Radix Isatidis has widely useful activities including anti-virus, anti-bacterial. Tryptanthrin, indigo, and indirubin are active ingredients in R. Isatidis. Response surface methodology (RSM)-optimized infrared-assisted extraction (IRAE) was developed and combined with HPLC for simultaneous determination of tryptanthrin, indigo, and indirubin from R. Isatidis. IRAE were investigated through extraction yields of the three components and optimized by RSM. The optimum conditions were as follows: infrared power of 129 W, solid/liquid ratio of 1:40 g/mL, and irradiation time of 22.5 min. IRAE conditions obtained by RSM were not only accurate, but also had practical value reflecting the expected optimization. Subsequently, this novel IRAE method was evaluated by extraction yield of the components of R. Isatidis samples from different regions. Compared with common extraction methods including maceration extraction (ME), reflux extraction (RE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), IRAE showed higher yield with advantages of no limitation of solvent selection, low cost, convenience under optimum extraction conditions. These results suggested the potential of RSM-optimized IRAE for extraction and analysis of the water-/fat-soluble compositions of Chinese herbal medicine. A simple chromatographic separation for simultaneous determination of tryptanthrin, indigo, and indirubin from Chinese herbal medicine R. Isatidis was performed on a C18 column (Diamonsil 150 mm × 4.6 mm i.d., 5 μm) with a mobile phase isocratic consisting of methanol and water at a flow-rate of 0.8 mL min−1. The retention times of tryptanthrin, indigo, and indirubin were 15.4, 31.9, and 58.6 min, respectively. The linear equations were obtained as follows: y = −3094.5744 + 21208.792x for tryptanthrin (R = 0.9998, 0.9–18.0 μg mL−1), y = 4730.0448 + 30180.567x for indigo (R = 0.9997, 0.5–10.0 μg mL−1) and y = −6582.9045 + 67069.312x for indirubin (R = 0.9997, 0.4–8.0 μg mL−1). The result showed that RSM-optimized IRAE was a simple, efficient pretreatment method for the analysis of complex matrix.