Cleaning of two mirrors in the first mirror unit using radiofrequency capacitively coupled plasma

First mirror(FM)cleaning,using radio frequency(RF)plasma,has been proposed to recover FM reflectivity in nuclear fusion reactors such as the International Thermonuclear Experimental Reactor(ITER).To investigate the influence of simultaneous cleaning of two mirrors on mirror cleaning efficiency and uniformity,experiments involving single-mirror cleaning and dual-mirror cleaning were conducted using RF capacitively coupled plasma in the laboratory.For the test and simultaneous cleaning of two mirrors,the FM and second mirror(SM),both measuring 110 mm×80 mm,were placed inside the first mirror unit(FMU).They were composed of 16 mirror samples,each with a dimension of 27.5 mm×20 mm.These mirror samples consist of a titanium-zirconium-molybdenum alloy substrate,a 500 nm Mo intermediate layer and a 30 nm Al_(2)O_(3) surface coating as a proxy for Be impurities.The cleaning of a single first mirror(SFM)and the simultaneous cleaning of the FM and SM(DFM and DSM)lasted for 9 h using Ar plasma at a pressure of 1 Pa.The total reflectivity of mirror samples on the DSM did not fully recover and varied with location,with a self-bias of−140 V.With a self-bias of−300 V,the total reflectivity of mirror samples on the SFM and DFM was fully recovered.The energy dispersive spectrometer results demonstrated that the Al_(2)O_(3) coating had been completely removed from these mirror samples.However,the mass loss of each mirror sample on the SFM and DFM before and after cleaning varied depending on its location,with higher mass loss observed for mirror samples located in the corners and lower loss for those in the center.Compared with SM cleaning,the simultaneous cleaning of two mirrors reduced the difference between the highest and lowest mass loss.Furthermore,this mass loss for the mirror samples of the DFM facing the DSM was increased.This indicated that mirror samples cleaned face to face in the FMU simultaneously could influence each other,highlighting the need for special attention in future studies.

Circular RNA circ_0003609 ameliorates hypertrophied ligamentum flavum by regulating the miR-155/SIRT1 axis

Background:Hypertrophy of the ligamentumflavum(HLF)is a common contributor to spinal stenosis which results in significant neurological impairments.Circular RNA(circRNA)circ_0003609 has been linked to HLF;however,the exact mechanism by which it causes this disease is unclear.Methods:Circ_0003609 expressions were regulated in HLF cells by overexpression vectors and RNA interference.Cell proliferation andfibrosis-related gene expression were checked by the Cell Counting Kit-8(CCK-8)assay and western blotting.CircBank’s prediction of the association between miR-155 and circ_0003609 was supported by a dual-luciferase reporter experiment.The function of the miR-155/sirtuin 1(SIRT1)axis in controlling HLFfibrosis was further examined.Results:Overexpression of circ_0003609 suppressed HLF cell propagation andfibrosis compared to its silencing.It was found that circ_0003609 served as the sponge for miR-155 and that the circ_0003609/miR-155 axis controlled thefibrosis of HLF cells.It was found that circ_0003609 acted as a sponge for miR-155,regulating thefibrosis of HLF cells.Further,miR-155 targets SIRT1,and the miR-155/SIRT1 axis promotes HLF cellfibrosis.Conclusion:Circ_0003609 ameliorates hypertrophied ligamentumflavum(LF)by modulating the miR-155/SIRT1 axis,indicating a potential treatment approach for HLF.

Study on plasma cleaning of the large-scale first mirror of the charge exchange recombination spectroscopy diagnostic on EAST

In the Experimental Advanced Superconducting Tokamak(EAST),the reflectivity of the charge exchange recombination spectroscopy(CXRS)first mirror(FM)was dramatically dropped down to 20%of the original value after the operation of two EAST experimental campaigns from 2014-2015,leading to degradation of the signal intensity of the CXRS diagnostic to an unacceptably low level.The radio frequency(RF)plasma cleaning of the CXRS FM with a dimension of 303×81×76 mm3 and a small curvature of 0.008 mm-1 was performed to remove deposits to recover the reflectivity.After 168 h cleaning by RF plasma,the maximum specular reflectivity of the FM could reach 92%of the original value at 532 nm,making the cleaned CXRS FM eligible to be reused for the CXRS diagnostic in the 2016 EAST campaign.Dedicated tests of sputtering polished mirror samples were performed to explore the cleaning uniformity and possible damage to the mirror surface.The specular reflectivity did not show obvious dependence on locations along the surface with the same cleaning time.The measured surface roughness gradually increased with sputtering time.The reflectivity remained almost unchanged regardless of different sputtering times and locations,indicating negligible damage to the FM surface even after 100 h sputtering.The recontaminated CXRS FM in the 2016 EAST campaign was firstly cleaned for 81 h,and the least reflectivity recovery for areas with relatively thick deposits was only 40%.After continuing cleaning to 147 h,redeposition of the sputtered residual deposits on the FM surface was observed.In the future for in situ cleaning of the FMs in EAST and ITER,deposits should be removed timely when they are very thin taking into account a very long cleaning time and presumable redeposition of thick and nonuniform deposits.

Characterization of dust collected in EAST after 2019 campaign

Dust presented in experimental advanced superconducting tokamak(EAST)with mixed plasmafacing materials has been collected and characterized for the first time.Dust at different positions in the vessel was collected by vacuum cleaner after the first experimental campaign in 2019.The shape,composition,and size of dust particles have been analyzed using different methods.About 80%of the total number of dust particles have size between 20 and 80μm,and most of dust particles are spherical,while schistose shape,columnar and irregular shape were also found.With the help of energy-dispersive x-ray spectroscopy different elements of dust have been identified,which is generally consistent with the different plasma-facing components in EAST.Both x-ray fluorescence and inductively coupled plasma emission spectrometer are complementary methods for measuring the dust composition quantitatively.It was found that the major components of dust were lithium dust in the form of lithium carbonate and lithium hydroxide,which is due to the routine lithium wall conditioning during EAST operation.

Thermal analysis on the EAST tungsten plasma facing components with shaping structure counteracting the misalignment issues

Tungsten monoblock type tiles with ITER dimensions along with supporting cassette components were installed at EAST＇s upper diverter during 2014 and EAST＇s lower diverter will also be upgraded in the future. These cassette structures pose critical issues on the high cumulative incident heat flux due to the leading edges and misalignments （0 ～ 1.5 mm）, which may result in the destruction or even melting of the tungsten tile. The present work summarizes the thermal analysis using ANSYS multiphysics software 15.0 performed on the actively cooled W tiles to evaluate the shaping effect on surface temperature. In the current heat flux conditions （Q11 ～ 100 MW m-2）, the adopted chamfer shaping （1 ×1 mm） can only reduce the maximum temperature by about 14%, but it also has a melting risk at the maximum misalignment of 1.5 mm. The candidate shaping solutions elliptical （round） edge, dome and fish-scale are analyzed for comparison and are identified not as good as the dual chamfer structure. A relatively good dual chamfer （2 ×13 mm） shaping forming a symmetrical sloping roof structure can effectively counteract the 1.5 mm misalignment, reducing the maximum temperature by up to 50%. However, in the future heat flux conditions （Q11 ～287 MW m-2）, it may only endure about 0.5 mm misalignment. Moreover, no proper shaping solution has been found that can avoid melting at the maximum misalignment of 1.5 mm. Thus, the engineering misalignment has to be limited to an acceptable level.

Super-resolution imaging in glycoscience: New developments and challenges

Carbohydrates on cell surfaces play a crucial role in a wide variety of biological processes,including cell adhesion,recognition and signaling,viral and bacterial infection,in°ammation and metastasis.However,owing to the large diversity and complexity of carbohydrate structure and nongenetically synthesis,glycoscience is the least understood¯eld compared with genomics and proteomics.Although the structures and functions of carbohydrates have been investigated by various conventional analysis methods,the distribution and role of carbohydrates in cell membranes remain elusive.This review focuses on the developments and challenges of super-resolution imaging in glycoscience through introduction of imaging principle and the available°uorescent probes for super-resolution imaging,the labeling strategies of carbohydrates,and the recent applications of super-resolution imaging in glycoscience,which will promote the super-resolution imaging technology as a promising tool to provide new insights into the study of glycoscience.

Repetitive cleaning of a stainless steel first mirror using radio frequency plasma

First mirrors（FMs） are crucial components of optical diagnostic systems in present-day tokamaks and future fusion reactors. Their lifetimes should be extremely limited due to their proximity to burning plasma, greatly influencing the safe operation of corresponding diagnostics.Repetitive cleaning is expected to provide a solution to the frequent replacement of contaminated FMs, thus prolonging their lifetimes. Three repetitive cleaning cycles using radio frequency plasma were applied to stainless steel（SS） FM samples, to evaluate the change of the mirrors＇ optical properties and morphology during each cycle. Amorphous carbon films were deposited on mirror surfaces under identical conditions in three cycles. In three cycles with identical cleaning parameters, the total reflectivity was restored at up to 95%. Nevertheless, with successive cleaning cycles, the FM surfaces gradually appeared to roughen due to damage to the grain boundaries. Correspondingly, the diffuse reflectivity increased from a few percent to 20%and 27% after the second and third cycles. After optimizing the cleaning parameters of the second and third cycles, the roughness showed a significant decrease, and simultaneously the increase of diffuse reflectivity was remarkably improved.

子宫内膜异位症患者冻融胚胎移植周期应用来曲唑行内膜准备方案有效性的随机对照研究

目的探讨子宫内膜异位症患者冻融胚胎移植周期应用来曲唑行内膜准备方案的临床有效性。方法采用随机对照研究,收集2019年1月至2020年12月期间在上海集爱遗传与不育诊疗中心进行冻融胚胎移植的143例子宫内膜异位症患者,根据内膜准备方案,计算机数字随机将患者分为来曲唑组(69例)和促性腺激素释放激素激动剂-激素替代(gonadotropin-releasing hormone agonist-hormone replacement therapy,GnRH-a-HRT)组(74例),主要观察指标为临床妊娠率。结果两组患者的移植胚胎数、囊胚移植比例、优质胚胎率、内膜准备时间差异均无统计学意义(均P>0.05)。GnRH-a-HRT组的雌二醇峰值[(417.8±102.7)ng/L]、移植日子宫内膜厚度[(10.2±1.6)mm]和移植周期药物费用[(3259.2±134.3)元]均高于来曲唑组[(188.5±44.8)ng/L,P<0.001;(8.9±1.4)mm,P=0.007;(356.9±79.9)元,P<0.001]。来曲唑组的超声检查次数[(3.8±0.9)次]和静脉抽血次数[(2.8±0.9)次]多于GnRH-a-HRT组[(2.4±0.4)次,P=0.041;(1.4±0.4)次,P=0.022]。两组的胚胎种植率、临床妊娠率、双胎妊娠率和异位妊娠率差异均无统计学意义(均P>0.05)。GnRH-a-HRT组的流产率相对来曲唑组有升高趋势,但差异无统计学意义(P>0.05)。结论子宫内膜异位症患者冻融胚胎移植周期应用来曲唑行内膜准备方案可获得与GnRH-a-HRT方案相同的胚胎种植率和临床妊娠率,并且来曲唑方案的药物费用低于GnRH-a-HRT方案。

狄尔斯-阿尔德反应催化剂

狄尔斯-阿尔德(Diels-Alder)可以构建结构丰富的有机化合物,被认为是现代有机化学中的基石反应之一。自1928年被发现以来,Diels-Alder(D-A)反应得到了深入发展,这主要是由于该反应能够产生六元环结构,可以一步反应得到具有四个立体中心的产物,从而大大增加分子的复杂性。这种特殊的转化已广泛应用于复杂天然产物的合成、药物化学以及材料科学等领域。近十年,大量天然生物酶(如SpnF、MaDA等)被发现可用于体外单独催化D-A反应,同时,大量的非酶催化剂(如路易斯酸、过渡金属与配体复合物等)也被应用于催化D-A反应。本文主要从D-A反应催化剂的类型分类,对近年来天然酶、酸、过渡金属、电催化等参与的D-A反应进行简要概述,同时对催化剂所存在的问题和局限性进行总结,并对今后发展做了展望。

Enhanced dSTORM imaging using fluorophores interacting with cucurbituril

Advanced fluorescence microscopy including single-molecule localization-based super-resolution imaging techniques requires bright and photostable dyes orproteins asfluorophores.The photophysical properties of fluorophores have been proven to be crucial for super-resolution microscopy's localization precision and imaging resolution.Fluorophores TAMRA and Atto Rho6 G,which can interact with macrocyclic host cucurbit[7]uril(CB7) to form host-guest compounds,were found to improve the fluorescence intensity and lifetimes of these dyes.We enhanced the localization precision of direct stochastic optical reconstruction microscopy(dSTORM) by introducing CB7 into the imaging buffer,and showed that the number of photons as well as localizations of both TAMRA and Atto Rho6 G increase over 2 times.

A Familial Phenotypic and Genetic Study of Mutations in PFN1 Associated with Amyotrophic Lateral Sclerosis

Dear Editor,Amyotrophic lateral sclerosis(ALS)is a progressive and fatal neurodegenerative disease that prominently affects both upper and lower motor neurons.The prevalence of ALS has been estimated at 2.6-3.0 per 100,000 in Europe,5.2 per 100,000 in the USA,and 1.9-9.9 per 100,000 in Asia[1-3].ALS is classified as sporadic(sALS)or familial(fALS),but only 5%-10% of cases are identified as familial[4,5].