RF-thermal-structural-RF coupled analysis on the travelling wave disk-loaded accelerating structure

Travelling wave (TW) disk-loaded accelerating structure is one of the key components in normal conducting (NC) linear accelerators, and has been studied for many years. In the design process, usually after the dimensions of each cell and the two couplers are finalized, the structure is fabricated and tuned, and then the whole structure characteristics can be measured by the vector network analyzer. Before the structure fabrication, the whole structure characteristics are less simulated limited by the available computer capability. In this paper, we described the method to do the RF-thermal-structural-RF coupled analysis on the TW disk-loaded structure with one single PC. In order to validate our method, we first analyzed and compared our RF simulation results on the 3m long BEPCII structure with the corresponding experimental results, which shows very good consistency. Finally, the RF-thermal-structure-RF coupled analysis results on the 1.35m long NSC KIPT linac accelerating structure are presented.Comment: 5 pages, 16 figures, Submitted to the Chinese Physics C (Formerly High Energy Physics and Nuclear Physics

Calcium Ions Stimulate the Hyperphosphorylation of Tau by Activating Microsomal Prostaglandin E Synthase 1

Alzheimer’s disease (AD) is reportedly associated with the accumulation of calcium ions (Ca2+), and this accumulation is responsible for the phosphorylation of tau. Although several lines of evidence demonstrate the above phenomenon, the inherent mechanisms remain unknown. Using APP/PS1 Tg mice and neuroblastoma (N)2a cells as in vivo and in vitro experimental models, we observed that Ca2+ stimulated the phosphorylation of tau by activating microsomal PGE synthase 1 (mPGES1) in a prostaglandin (PG) E2-dependent EP receptor-activating manner. Specifically, the highly accumulated Ca2+ stimulated the expression of mPGES1 and the synthesis of PGE2. Treatment with the inhibitor of Ca2+ transporter, NMDAR, attenuated the expression of mPGES1 and the production of PGE2 were attenuated in S(+)-ketamine-treated APP/PS1 Tg mice. Elevated levels of PGE2 were responsible for the hyperphosphorylation of tau in an EP-1-, EP-2-, and EP-3-dependent but not EP4-dependent cyclin-dependent kinase (Cdk) 5-activating manner. Reciprocally, the knockdown of the expression of mPGES1 ameliorated the expected cognitive decline by inhibiting the phosphorylation of tau in APP/PS1 Tg mice. Moreover, CDK5 was found to be located downstream of EP1-3 to regulate the phosphorylation of tau though the cleavage of p35 to p25. Finally, the phosphorylation of tau by Ca2+ contributed to the cognitive decline of APP/PS1 Tg mice

Green synthesis of CuO nanoparticles using Cassia auriculata leaf extract and in vitro evaluation of their biocompatibility with rheumatoid arthritis macrophages (RAW 264.7)

Purpose: To undertake green synthesis of copper oxide nanoparticles (CuO NPs) using Cassia auriculata leaf extract and evaluate their biocompatibility with rheumatoid arthritis macrophages (RAW 264.7 cell line).Methods: CuO NPs were prepared by heating a mixture of 10 mL of 0.01 M CuSO4 solution and 30 mL of C. auriculata extract at 80 °C for 1 h. The synthesized CuO NPs were characterized by x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UVVis), energy-dispersive x-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The cytotoxicity of the NPs against RAW 264.7 cells was studied using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Results: The gradual change in color of the reaction solution from brownish yellow to dark brown indicated CuO NP formation. TEM images revealed spherical, polydispersed NPs (mean particle size, 23 nm). FTIR results indicated capping of polyphenols on the surface of the NPs. Most RAW 264.7 cells (> 95 %) remained alive following exposure to CuO NPs at concentrations of up to 200 μg/mL, indicating biocompatible with the cells.Conclusion: An eco-friendly, low-cost, biosynthetic method for CuO NP preparation has been successfully developed using C. auriculata leaf extract. Furthermore, the nanoparticles are biocompatible with RAW 264.7 cell line.Keywords: Cassia auriculata extract, Copper oxide nanoparticles, RAW 264.7 cell line, Rheumatoid arthriti

The four-step total synthesis of (-)-chaetominine

National Basic Research Program (973 Program) of China [2010CB833200]; NSF of China [21332007, 21072160]; Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT) of Ministry of Education, ChinaThe total synthesis of the alkaloid (-)-chaetominine (1) has been achieved in four steps with an overall yield of 33.4%. Key features of our strategy include a one-pot cascade indole epoxidation - epoxide ring-opening cyclization - lactamization reaction sequence, and the use of a nitro group as a latent amino group for the one-pot construction of the quinazolinone ring. This constitutes a step economical, redox economical and protecting group-free total synthesis