113 research outputs found

    Synthesizing polypropylene with percolation network catalyzed by inorganic nanoparticles-functionalized Ziegler-Natta catalyst

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    Polypropylene is one of the most widely used synthetic resins, which is mainly synthesized with Ziegler-Natta catalysts. In this paper, the functionalized Ziegler-Natta catalyst is applied to prepare high-performance polypropylene. A new way to synthesize functionalized Ziegler-Natta catalysts is to dope with inorganic nanoparticles. The MgCl2/TiCl4/BMMF catalysts doped with halloysite nanotubes were prepared and applied to synthesize polypropylene containing less than 200ppm halloysite nanotubes. It is found that doping nanotubes in Ziegler-Natta catalyst has little impact on the structure, composition and activity of the catalyst, and polypropylene with high isotactic degree and molecular weight was synthesized with the functionalized Ziegler-Natta catalyst. Halloysite nanotubes are found to be dispersed in polypropylene in the form of individual nanotube, forming percolated network in the polymer melt effectively. Moreover, the polypropylene containing halloysite nanotubes exhibited better mechanical and thermal resistance properties as compared with conventional polypropylene, and the thermo-oxidative properties of which do not deteriorate as the introduction of nanotubes. This research provides a facile way to relieve the contradiction between the high activity of catalyst and high content of nanoparticles during the preparation of polyolefin nanocomposites by in-situ polymerization, and a new idea to prepare polyolefin nanocomposites by in-situ polymerization

    Quench of a Single-Layer ReBCO CORC Cable with Non-Uniform Terminal Contact Resistance

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    ReBCO conductor-on-round-core (CORC) cable has become a promising candidate for high temperature superconducting (HTS) power applications, due to its great mechanical strength, high current carrying capacity, high flexibility, and low ac losses. However, ReBCO coated conductors are at risk of quenching, which significantly affects the thermal stability and reliability of the CORC cable. Three-dimensional (3-D) numerical study on the quench behavior of the CORC cable remains a challenge, for its complex geometry is difficult to cope with. In this paper, a 3-D time-dependent multi-physics quench model based on the T-A formulation has been developed. Three modules are coupled in this model; the T-A formulation model, a heat transfer model, and an equivalent circuit model. The quench behavior of a single-layer ReBCO CORC cable with non-uniform terminal contact resistances has been studied, when a hotspot is imposed on one of the tapes to induce a local quench. Results show that, the CORC cable has the highest MQE; in other words, it is the most stable situation, when the hotspot-induced quench occurs on the tape with the middle value of terminal contact resistance

    Clinical efficacy of Osteoking in knee osteoarthritis therapy: a prospective, multicenter, non-randomized controlled study in China

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    BackgroundOsteoking has been extensively used for the treatment of knee osteoarthritis (KOA). However, it is lack of high-quality evidence on the clinical efficacy of Osteoking against KOA and the comparison with that of nonsteroidal anti-inflammatory drugs (NSAIDs).AimsTo evaluate the efficacy and safety of Osteoking in treating KOA.MethodsIn the current study, a total of 501 subjects were recruited from 20 medical centers, and were divided into the Osteoking treatment group (n = 428) and the NSAIDs treatment group (n = 73). The Propensity Score Matching method was used to balance baseline data of different groups. Then, the therapeutic effects of Osteoking and NSAIDs against KOA were evaluated using VAS score, WOMAC score, EQ-5D-3L and EQ-VAS, while the safety of the two treatment were both assessed based on dry mouth, dizziness, diarrhea, etc.ResultsAfter 8 weeks of treatment, the Osteoking group was compared with the NSAIDs group, the VAS score [2.00 (1.00, 3.00) vs. 3.00 (2.00, 4.00)], WOMAC pain score [10.00 (8.00, 13.00) vs. 11.00 (8.00, 16.00) ], WOMAC physical function score [32.00 (23.00, 39.00) vs. 39.07 ± 16.45], WOMAC total score [44.00 (31.00, 55.00) vs. 53.31 ± 22.47) ], EQ-5D-3L score [0.91 (0.73, 0.91) vs. 0.73 (0.63, 0.83) ] and EQ-VAS score [80.00 (79.00, 90.00) vs. 80.00 (70.00, 84.00) ] were improved by the treatment of Osteoking for 8 weeks more effectively than that by the treatment of NSAIDs. After 8 weeks of treatment with Osteoking, the VAS scores of KOA patients with the treatment of Osteoking for 8 weeks were reduced from 6.00 (5.00, 7.00) to 2.00 (1.00, 3.00) (p < 0.05), which was better than those with the treatment of NSAIDs starting from 2 weeks during this clinical observation. Importantly, further subgroup analysis revealed that the treatment of Osteoking was more suitable for alleviating various clinical symptoms of KOA patients over 65 years old, with female, KL II-III grade and VAS 4-7 scores, while the clinical efficacy of NSAIDs was better in KOA patients under 65 years old and with VAS 8–10 scores. Of note, there were no differences in adverse events and adverse reactions between the treatment groups of the two drugs.ConclusionOsteoking may exert a satisfying efficacy in relieving joint pain and improving life quality of KOA patients without any adverse reactions, especially for patients with KL II-III grades and VAS 4–7 scores.Clinical Trial Registration:https://www.chictr.org.cn/showproj.html?proj=55387, Identifier ChiCTR200003447

    Arsenic trioxide exerts synergistic effects with cisplatin on non-small cell lung cancer cells via apoptosis induction

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    <p>Abstract</p> <p>Background</p> <p>Despite multidisciplinary treatment, lung cancer remains a highly lethal disease due to poor response to chemotherapy. The identification of therapeutic agents with synergistic effects with traditional drugs is an alternative for lung cancer therapy. In this study, the synergistic effects of arsenic trioxide (As<sub>2</sub>O<sub>3</sub>) with cisplatin (DDP) on A549 and H460 non-small cell lung cancer (NSCLC) cells were explored.</p> <p>Methods</p> <p>A549 and H460 human lung cancer cells were treated with As<sub>2</sub>O<sub>3 </sub>and/or DDP. Cell growth curves, cell proliferation, cell cycle, and apoptosis of human cancer cell lines were determined by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) method, clonogenic assay, and flow cytometry (FCM). Apoptosis was further assessed by TUNEL staining. Cell cycle and apoptosis related protein p21, cyclin D1, Bcl-2, bax, clusterin, and caspase-3 were detected by western blot.</p> <p>Results</p> <p>MTT and clonogenic assay showed As<sub>2</sub>O<sub>3 </sub>within 10<sup>-2 </sup>μM to 10 μM exerted inhibition on the proliferation of NSCLC cells, and 2.5 μM As<sub>2</sub>O<sub>3 </sub>exerted synergistic inhibition on proliferation with 3 μg/ml DDP. The combination indices (CI) for A549 and H460 were 0.5 and 0.6, respectively, as confirmed by the synergism of As<sub>2</sub>O<sub>3 </sub>with DDP. FCM showed As<sub>2</sub>O<sub>3 </sub>did not affect the cell cycle. The G0/G1 fraction ranged from 57% to 62% for controlled A549 cells and cells treated with As<sub>2</sub>O<sub>3 </sub>and/or DDP. The G0/G1 fraction ranged from 37% to 42% for controlled H460 cells and cells treated with As<sub>2</sub>O<sub>3 </sub>and/or DDP. FCM and TUNEL staining illustrated that the combination of As<sub>2</sub>O<sub>3 </sub>and DDP provoked synergistic effects on apoptosis induction based on the analysis of the apoptosis index. Western blotting revealed that the expression of cell cycle related protein p21 and cyclin D1 were not affected by the treatments, whereas apoptosis related protein bax, Bcl-2, and clusterin were significantly regulated by As<sub>2</sub>O<sub>3 </sub>and/or DDP treatments compared with controls. The expression of caspase-3 in cells treated with the combination of As<sub>2</sub>O<sub>3 </sub>and DDP did not differ from that in cells treated with a single agent.</p> <p>Conclusion</p> <p>As<sub>2</sub>O<sub>3 </sub>exerted synergistic effects with DDP on NSCLC cells, and the synergistic effects were partly due to the induction of caspase-independent apoptosis.</p

    Low temperature and temperature decline increase acute aortic dissection risk and burden: A nationwide case crossover analysis at hourly level among 40,270 patients.

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    Background: Acute aortic dissection (AAD) is a life-threatening cardiovascular emergency with high mortality, so identifying modifiable risk factors of AAD is of great public health significance. The associations of non-optimal temperature and temperature variability with AAD onset and the disease burden have not been fully understood. Methods: We conducted a time-stratified case-crossover study using a nationwide registry dataset from 1,868 hospitals in 313 Chinese cities. Conditional logistic regression and distributed lag models were used to investigate associations of temperature and temperature changes between neighboring days (TCN) with the hourly AAD onset and calculate the attributable fractions. We also evaluated the heterogeneity of the associations. Findings: A total of 40,270 eligible AAD cases were included. The exposure-response curves for temperature and TCN with AAD onset risk were both inverse and approximately linear. The risks were present on the concurrent hour (for temperature) or day (for TCN) and lasted for almost 1 day. The cumulative relative risks of AAD were 1.027 and 1.026 per 1°C lower temperature and temperature decline between neighboring days, respectively. The associations were significant during the non-heating period, but were not present during the heating period in cities with central heating. 23.13% of AAD cases nationwide were attributable to low temperature and 1.58% were attributable to temperature decline from the previous day. Interpretation: This is the largest nationwide study demonstrating robust associations of low temperature and temperature decline with AAD onset. We, for the first time, calculated the corresponding disease burden and further showed that central heating may be a modifier for temperature-related AAD risk and burden. Funding: This work was supported by the National Natural Science Foundation of China (92043301 and 92143301), Shanghai International Science and Technology Partnership Project (No. 21230780200), the Medical Research Council-UK (MR/R013349/1), and the Natural Environment Research Council UK (NE/R009384/1)
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