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.
Mobile phone addiction (MPA) is frequently reported to be correlated with anxiety, depression, stress, impulsivity, and sleep quality among college students. However, to date, there is no consensus on the extent to which those factors are correlated with MPA among college students. We thus performed a meta-analysis to quantitatively synthesize the previous findings.
A systematic review and meta-analysis was conducted by searching PubMed, Embase, Cochrane Library, Wanfang, Chinese National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and Chinese Biological Medicine (CBM) databases from inception to August 1, 2020. Pooled Pearson's correlation coefficients between MPA and anxiety, depression, impulsivity, and sleep quality were calculated by R software using random effects model.
Forty studies involving a total of 33, 650 college students were identified. Weak-to-moderate positive correlations were found between MPA and anxiety, depression, impulsivity and sleep quality (anxiety: summary r = 0.39, 95% CI = 0.34–0.45, P < 0.001, I2 = 84.9%; depression: summary r = 0.36, 95% CI = 0.32–0.40, P < 0.001, I2 = 84.2%; impulsivity: summary r = 0.38, 95% CI = 0.28–0.47, P < 0.001, I2 = 94.7%; sleep quality: summary r = 0.28, 95% CI = 0.22–0.33, P < 0.001, I2 = 85.6%). The pooled correlations revealed some discrepancies when stratified by some moderators. The robustness of our findings was further confirmed by sensitivity analyses.
The current meta-analysis provided solid evidence that MPA was positively correlated with anxiety, depression, impulsivity, and sleep quality. This indicated that college students with MPA were more likely to develop high levels of anxiety, depression, and impulsivity and suffer from poor sleep quality. More studies, especially large prospective studies, are warranted to verify our findings.
Authors:Li Ying Yang, Ting Yue, Jie Lan Ding and Tao Han
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.
Authors:Ying Xu, Man Xue, Jinjin Li, Liujie Zhang and Yuanchen Cui
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.
Authors:Xueli Li, Xiaoyi Yang, Ying Yang and Jianguang Li
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.
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 R2, >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.
Authors:Ying Lan, Zhe Su, Xingliang Li, Zhaoqun Jiang, Jun Jin, Jiali Xie and Shoujian Li
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.
Authors:He Zhang, Mei Meng, Li Chen, Fang Wang, Jing Zhang, Ying Jiang and Wen Wang
The newly emerged chromatographic fngerprint analysis represents a rational approach assessment of Traditional Chinese Medicine (TCM) and its preparations. In the present paper, a quick and reliable analytical method was developed for the quality assessment of QiYi capsules (QY) using high-performance thin-layer chromatography (HPTLC) with the reference of Tripterygium wilfordii. The unique properties of the HPTLC fngerprint were validated by analyzing 10 batches of QY samples. The 9 common peaks of the HPTLC images of QY and the different RF and peak area ratios of the chemical distribution could directly discern the stability by comparison of 10 samples, and also, the 9 common peaks were selected to evaluate the similarities of QY; the similarities of 10 batches of QY were more than 0.960, which indicated a standardized consistency and reliable quality of QY. Therefore, the newly developed HPTLC fngerprint method provided an easy way for sample characterization and differentiation; it allowed for the quality assessment of QY capsules with the reference of T. wilfordii.
This article describes the synthesis of a liquid crystalline curing agent 4,4′-bis-(4-amine-butyloxy)-biphenyl (BABB), and its application as a curing agent for the epoxy resin (DGEBA) in comparison with normal curing agent, 4,4′-diaminobiphenyl (DABP). BABB was investigated with polarized optical microscopy, differential scanning calorimetry, and small-angle X-ray scatting, and the results showed that BABB displayed smectic liquid crystalline phase. The curing behaviors of DGEBA cured with BABB and DABP were studied by using differential scanning calorimetry (DSC), polarized optical microscopy (POM), and dynamic mechanical analysis (DMA). The results indicated that BABB showed a higher chemical reactivity than DABP. The kinetics was studied under isothermal conditions using an isoconversional method, and the isothermal DSC data can be fitted reasonably by an autocatalytic curing model. The nematic droplet texture was observed for the resulting polymer network of DGEBA/BABB system, while the DGEBA/DABP system showed an isotropic state. The storage modulus of DGEBA/BABB system was enhanced in comparison with DGEBA/DABP system because of the formation of LC phase, whereas the glass transition temperatures decreased because of the introduction of flexible spacer group.