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Summary The Institute of Higher Education, Shanghai Jiao Tong University published on the web the Academic Ranking of World Universities and attracted wide attentions worldwide. 60% of their criteria are based on the databases using scientometrics. They were aware of all possible technical problems, have gone through “clean up” processes and made necessary corrections. Highly cited researchers and articles published in Nature and Science were identified one by one and attributed to the correct institutions. They are confident that errors including human ones in their data are less than two percent. They will continue their ranking efforts, improve their ranking methodologies and provide more choices on the ranking lists.

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A new method for the analysis of four target flavonoids in two kinds of citrus samples by ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed. Main variables affecting the UHPSFC separation were optimized, and under the optimized conditions the four target compounds (tangeretin, nobiletin, hesperetin and naringenin) can be separated within 10 min. The UHPSFC method allowed the determination of the four target compounds in the diluted stock solutions with limit of detection (LOD) ranging from 1.08 to 2.28 μg mL−1, and limit of quantification (LOQ) ranging from 1.45 to 4.52 μg mL−1, respectively. The coefficients of determination (R 2) of the calibration curves were higher than 0.9950. The recoveries of the four target compounds at three different concentrations were in the range of 82.4–117.6%. The validation results demonstrated that the proposed method is simple, accurate, time-saving and environment friendly, and it is applicable to a variety of complex samples such as medicine-food dual purpose herbs and functional foods.

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Abstract  

A cellulose xanthate supported palladium(0) complex was synthesized using a simple method and characterized by XPS, TG/DTA etc. The complex has good thermal stability from room temperature to 250 °C and it was found to be an efficient catalyst for the Heck reaction of acrylic acid or styrene with aryl iodide at low temperature under atmospheric pressure, and the substituted trans-cinnamic acid or 1, 2-stilbene was obtained with high yield at 90 °C. The reaction duration is about 8 h. The cellulose xanthate supported palladium(0) complex could be separated from the reaction mixture easily and reused for several cycles. The yield of the product was up to 55.3% when the catalyst was run for 10 times. The active center in the complex is Pd metal.

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Using a collection of papers gathered from the Web of Science, and defining disciplines by the JCR classification, this paper compares the disciplinary structure of the G7 countries (representing high S&T level countries) and the BRIC countries (representing fast breaking countries in S&T) by using bibliometric methods. It discusses the similarity and the balance of their disciplinary structure. We found that: (1) High S&T level countries have a similar national disciplinary structure; (2) In recent years the disciplinary structure of the BRIC countries has become more and more similar to that of the G7 countries; (3) The disciplinary structure of the G7 countries is more balanced than that of the BRIC countries (4) In the G7 countries more emphasis goes to the life sciences, while BRIC countries focus on physics, chemistry, mathematics and engineering.

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A new crystalline microporous inorganic ion-exchanger, indium sulphide, was synthesized and characterized. Elemental analysis suggests that the probable composition of this exchanger is [In10.5S14.5]·[(H2NCH2CH2-NHCH2)2]2.5. This exchanger is stable in dilute acid (<2M) has strong binding ability with Sr2+, and a quicker exchange kinetic equilibrium taking its crystalline nature into account.

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Acta Chromatographica
Authors: Yun Wang, Jianhong Chen, Yutian Li, Puling Li, Javed Iqbal, Ying Chen, Yinlian Ma, and Cun Zhang

A reliable and rapid high-performance liquid chromatography coupled with diode array detector method (HPLC–DAD) was established and validated to determine eight gingerol simultaneously in the rhizomes of Zingiber offcinale Rosc. The separation of eight compounds (4-hydroxy-3-methoxy-benzenebutanol,3,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl) decane, 3,5-dihydroxy-1-(3,4-dimethoxyphenyl) decane, 6-gingerol, 8-gingerol, 6-shogaol, 5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1,4-decadien-3-one, and 10-gingerol) were performed on an Agilent TC(2) C18 (250 mm × 4.6 mm, 5 μm) at 30 °C using acetonitrile (A) and 1% formic acid aqueous solution (B) as the mobile phase with gradient elution (0–10 min, 20%–35% A; 10–28 min, 35%–55% A; 28–35 min, 55%–60% A; 35–55 min, 60%–70% A; 55.01–60 min, 100%–100% A). The detection wavelength was set at 280 nm, and the flow rate was 0.8 mL/min. Validation of the analytical method was performed by linearity, precision, and accuracy test. All compounds were quantified with good linear calibration curves (coefficient of determination R 2, >0.9999). The method showed good precision with overall coefficients of variation between 0.56% and 0.84%. The range of recovery was from 95.50% to 104.14% for the analytes. This method was successfully applied to quantify eight gingerols in Z. offcinale Rosc from different regions in China, so it can provide quality assessment for this medicine.

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This study aims at establishing a thin-layer chromatographic (TLC) scanning method for the determination of three alkaloids in Sophora alopecuroides and preliminary screening of antioxidant active components in S. alopecuroides with TLC—bioautography technology. The alkaloids in S. alopecuroides were identified by silica gel thin-layer chromatography; the expansion agent was toluene— acetone—methanol—ammonia—water (8:3:0.2:0.5:8), and the chromogenic agent was modified bismuth potassium iodide solution, sophoridine, matrine, and sophocarpine in S. alopecuroides by TLC scanning at 500 nm. The linear ranges were 0.4152–2.4912 μg for sophordine, 0.4245–2.5470 μg for matrine, and 0.4101– 2.4606 μg for sophocarpine, with correlation coefficients of 0.9939, 0.9956, and 0.9975. Ultraviolet (UV) method was used to determine the total scavenging activity of the 2,2-diphenyl-1-picrylhdrazyl (DPPH) free radical. The best TLC identification condition was selected, and the antioxidant activity of DPPH was screened with the color. DPPH tests indicated that IC50 of S. alopecuroides was 0.40 mg mL−1. The TLC—bioautography technology showed the alkaloids in the purple background, and a white spot was not evident. Precision, accuracy, and repeatability of the TLC scanning method were evaluated, and the results were in accordance with the requirements of methodology validation. S. alopecuroides exhibits certain antioxidant activity, but the three alkaloids do not exhibit an evident antioxidant effect, and the unknown components of S. alopecuroides show weak antioxidant effect. The specific components need further studies.

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Abstract  

The heat capacities of Ln(Me2dtc)3(C12H8N2) (Ln = La, Pr, Nd, Sm, Me2dtc = dimethyldithiocarbamate) have been measured by the adiabatic method within the temperature range 78–404 K. The temperature dependencies of the heat capacities, C p,m[La(Me2dtc)3(C12H8N2)] = 542.097 + 229.576 X − 27.169 X 2 + 14.596 X 3 − 7.135 X 4 (J K−1 mol−1), C p,m[Pr(Me2dtc)3(C12H8N2)] = 500.252 + 314.114 X − 17.596 X 2 − 0.131 X 3 + 16.627 X 4 (J K−1 mol−1), C p,m[Nd(Me2dtc)3(C12H8N2)] = 543.586 + 213.876 X − 68.040 X 2 + 1.173 X 3 + 2.563 X 4 (J K−1 mol−1) and C p,m[Sm(Me2dtc)3(C12H8N2)] = 528.650 + 216.408 X − 16.492 X 2 + 12.076 X 3 + 4.912 X 4 (J K−1 mol−1), were derived by the least-squares method from the experimental data. The heat capacities of Ce(Me2dtc)3(C12H8N2) and Pm(Me2dtc)3(C12H8N2) at 298.15 K were evaluated to be 617.99 and 610.09 J K−1 mol−1, respectively. Furthermore, the thermodynamic functions (entropy, enthalpy and Gibbs free energy) have been calculated using the obtained experimental heat capacity data.

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Abstract

A new homologous series of curing agents (LCECAn) containing 4,4′-biphenyl and n-methylene units (n = 2, 4, 6) were successfully synthesized. The curing behaviors of a commercial diglycidyl ether of bisphenol-A epoxy (E-51) and 4,4′-bis(2,3-epoxypropoxy)biphenyl (LCE) by using LCECAn as the curing agent have been investigated by differential scanning calorimetry (DSC), respectively. The Ozawa equation was applied to the curing kinetics based upon the dynamic DSC data, and the isothermal DSC data were fitted using an autocatalytic curing model. The glass transition temperatures (T g) of the cured epoxy systems were determined by DSC upon the second heating, and the thermal decomposition temperatures (T d) were obtained by thermogravimetric (TG) analyses. The results show that the number of methylene units in LCECAn has little influence on the curing temperatures of E-51/LCECAn and LCE/LCECAn systems. In addition, the activation energies obtained by the dynamic method proved to be larger than those by the isothermal method. Furthermore, both the T g and T d of the cured E-51/LCECAn systems and LCE/LCECAn systems decreased with the increase in the number of methylene units in LCECAn.

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