Divergence angle consideration in energy spread measurement for high-quality relativistic electron beam in laser wakefield acceleration

The thorough exploration of the transverse quality represented by divergence angle has been lacking yet in the energy spread measurement of the relativistic electron beam for laser wakefield acceleration(LWFA). In this work, we fill this gap by numerical simulations based on the experimental data, which indicate that in a C-shape magnet, magnetic field possesses the beam focusing effect, considering that the divergence angle will result in an increase in the full width at half maxima(FWHM) of the electron density distribution in a uniformly isotropic manner, while the length-to-width ratio decreases. This indicates that the energy spread obtained from the electron deflection distance is smaller than the actual value, regardless of the divergence angle. A promising and efficient way to accurately correct the value is presented by considering the divergence angle(for instance, for an electron beam with a length-to-width ratio of 1.12, the energy spread correct from 1.2% to 1.5%), providing a reference for developing the high-quality electron beam source.

Single-frequency linearly polarized Q-switched fiber laser based on Nb_(2)GeTe_(4)saturable absorber

We report a single-frequency linearly polarized Q-switched fiber laser based on an Nb_(2)GeTe_(4)saturable absorber(SA).The Nb_(2)GeTe_(4)SA triggers passive Q-switching of the laser,and an un-pumped Yb-doped fiber together with a 0.08-nmbandwidth polarization-maintaining fiber Bragg grating(FBG)acts as an ultra-narrow bandwidth filter to realize singlelongitudinal-mode(SLM)oscillation.The devices used in the laser are all kept polarized,so as to ensure linearly polarized laser output.Stable SLM linearly polarized Q-switching operation at 1064.6 nm is successfully achieved,producing a laser with a shortest pulse width of 1.36μs,a linewidth of 28.4 MHz,a repetition rate of 28.3 kHz-95.9 kHz,and a polarization extinction ratio of about 30 dB.It is believed that the single-frequency linearly polarized pulsed fiber laser studied in this paper has great application value in gravitational wave detection,beam combining,nonlinear frequency conversion,and other fields.

角膜地形图引导与波前像差优化的FS-LASIK术后高阶像差比较的Meta分析

目的:系统评价经角膜地形图引导与波前像差优化的FS-LASIK术后屈光度与高阶像差的增幅。方法:检索PubMed、the Cochrane Library、Medline、CNKI、CBM、VIP和WanFang Data数据库中的RCT与CT研究,语言限定为中文或英文,语言限定为中文或英文。对纳入的RCT与CT文献分别采用《Cochrane干预措施系统评价手册》中偏倚风险评价工具与《NOS量表》进行质量评价;对纳入文献的发表偏倚采用Egger检验进行检测;采用Review Manager 5.4软件进行Meta分析。结果:共有8篇文献符合纳入和排除标准,包含987例研究对象(角膜地形图引导组482例,波前像差优化组505例)。Meta分析结果显示:地形图引导组术后等效屈光度高于波前优化组[WMD=0.11,95%CI(0.07,0.14),P<0.00001];与波前优化组相比,地形图引导组术后能够获得更低的HOAs[WMD=-0.09,95%CI(-0.13,-0.05),P<0.0001]、球差[WMD=-0.05,95%CI(-0.09,-0.01),P=0.008]、彗差[WMD=-0.08,95%CI(-0.12,-0.05),P<0.00001]增幅。结论:经角膜地形图引导的FS-LASIK手术方式能使患者获得更高的屈光度,并有效降低术后HOAs、球差、彗差增幅。

Protective effect and mechanism of dexmedetomidine on lung injury in diabetic mice with myocardial ischemia reperfusion

Objective:To evaluate the protective effect of dexmedetomidine and its mechanism on the lung after myocardial ischemia reperfusion in diabetic mice.Methods:Adult diabetic db/db mice aged 15 weeks were selected.The sham operation group(S group),ischemic reperfusion group(IR group),dexmedetomidine post-treatment group(POST-D)and dexmedetomidine pre-treatment group(PRE-D)were set respectively.The IR group of mice underwent ligation of anterior descending branch of left coronary artery for 30min and readministration for 120min.The post-D group and the pre-D group were intraperitoneally injected with 50 ug/kg DEX before surgery and during reperfusion,respectively.Orbital blood was extracted at 120min of reperfusion,serum levels of creatine kinase isoenzyme MB and inflammatory cytokines IL-6,IFN-γand IL-10 were detected,then mice were sacrificed and lung tissue was taken,the ratio of wet and dry weight(W/D)was determined,lung histopathological morphology was observed under light microscope,superoxide dismutase(SOD)and malondialdehyde(MDA)contents were determined,Western Blot was used to detect the expressions of Sirt1,GRP78 and CHOP in lung tissue.Results:Compared with the S group,the IR group rats had severe lung injury,including increased lung W/D value,increased serum CK-MB、IL-6 and IFN-γlevels,decreased serum IL-10,increased serum MDA content,decreased SOD activity,down-regulated Sirt1 expression,up-regulated GRP78 and CHOP expression.Compared with IR group,lung histopathological injury was reduced in post-D group and pre-D group,lung W/D value was decreased,serum CK-MB、IL-6 and IFN-γlevels were decreased,serum IL-10 was increased,serum MDA content was reduced,SOD activity was rised,the expression of Sirt1 was up-regulated,and GRP78 and CHOP were down-regulated.Compared with the post-D group,the degree of lung tissue injury in the pre-D group was reduced,but the differences in various indicators were not statistically significant.Conclusion:Dexmedetomidine can alleviate acute lung injury after myocardial ischemia reperfusion in diabetic mice,and the mechanism may be related to the up-regulation of Sirt1 and the inhibition of endoplasmic reticulum stress.

The changes and clinical significance of CD4+CD25+ and CD4+CD28-T cells in peripheral blood of patients with stroke

Objective:To study the changes of CD4+CD25+ and CD4+CD28-T cells in peripheral blood of patients with stroke and their correlation with neuronal damage markers, inflammatory cytokines and plaque stability indicators.Methods: The patients who were diagnosed with acute ischemic stroke in our hospital between June 2014 and December 2017 were selected as the stroke group of the research, and healthy volunteers who received physical examination during the same period were selected as the control group. Peripheral blood was collected to determine the contents of CD4+CD25+ and CD4+CD28-T cells, and serum was collected to determine the contents of neuron damage markers, inflammatory cytokines and plaque stability indicators.Results: Peripheral blood CD4+CD25+ cell content as well as serum BDNF, IGF-1, IL-10, TGF-β1, TIMP2 and Vaspin contents of stroke group was lower than those of control group whereas peripheral blood CD4+CD28-T cell content as well as serum NSE, VILIP-1, ET-1, IL-6, CXCL12, VCAM-1, P-selectin, ox-LDL, CatS, ICTP and VEGF contents was higher than those of control group;peripheral blood CD4+CD25+ cell content of stroke group was positively correlated with serum BDNF, IGF-1, IL-10, TGF-β1, TIMP2 and Vaspin contents, and negatively correlated with NSE, VILIP-1, ET-1, IL-6, CXCL12, VCAM-1, P-selectin, ox-LDL, CatS, ICTP and VEGF contents;peripheral blood CD4+CD28-T cell content was negatively correlated with serum BDNF, IGF-1, IL-10, TGF-β1, TIMP2 and Vaspin contents, and positively correlated with NSE, VILIP-1, ET-1, IL-6, CXCL12, VCAM-1, P-selectin, ox-LDL, CatS, ICTP and VEGF contents.Conclusion: The changes of CD4+CD25+ and CD4+CD28-T cells in peripheral blood of patients with stroke can aggravate the neuron damage and promote the inflammatory response activation and plaque stability decline.

Effect of ticagrelor sequential therapy after PCI on platelet function and cytokine secretion in patients with ACS

Objective:To explore the effect of ticagrelor sequential therapy after PCI on platelet function and cytokine secretion in patients with ACS.Methods: 176 patients with ACS who underwent PCI in our hospital between January 2015 and January 2018 were divided into the control group (n=92) who received conventional therapy and the ticagrelor group (n=84) who received ticagrelor sequential therapy based on the different therapies after PCI. The differences in serum platelet activation function indexes, myocardial injury indexes and chemokines were compared between the two groups of patients immediately after admission and 1 week after PCI.Results: Immediately after admission, serum platelet activation function indexes, myocardial injury indexes and chemokines were not significantly different between the two groups;1 week after PCI, serum platelet activation function indexes CD62p and CD63 levels of ticagrelor group were lower than those of control group;serum myocardial injury indexes hs-cTnⅠ, IMA, H-FABP and CK-MB contents were lower than those of control group;serum chemokines CXCL16, RANTES and MCP-1 contents were lower than those of control group.Conclusion: ticagrelor sequential therapy after PCI can effectively inhibit the excessive activation of platelets, reduce the postoperative myocardial injury and suppress the systemic inflammatory response in patients with ACS.

面向集成电路产业的电子电镀研究方法

电子电镀是集成电路等高端电子制造产业的核心技术之一,其技术特点和难点在于在微纳米尺度通孔、盲孔、沟槽等限域空间内部实现金属镀层的均匀增厚或致密填充.然而,我国针对面向集成电路制造产业的微纳尺度电子电镀过程中的金属电沉积的表界面反应过程、添加剂的分子作用机制及其协同作用、以及镀层的理化结构与电学性能之间的构效关系的基础研究十分薄弱,缺乏系统和成熟的理论体系和研究方法.结合厦门大学电镀学科多年的科研工作,本文拟归纳微纳米尺度电子电镀的关键科学问题和技术难点,介绍电子电镀镀液体系的发展,梳理电子电镀的经典电化学研究方法和电化学原位先进研究方法,展望电子电镀工况研究方法的必要性和紧迫性,希望助力发展先进的电子电镀研究方法,推动电子电镀基础理论和工艺技术研究的进步.

Meplazumab in hospitalized adults with severe COVID-19(DEFLECT):a multicenter,seamless phase 2/3,randomized,third-party double-blind clinical trial

Meplazumab,a humanized CD147 antibody,has shown favourable safety and efficacy in our previous clinical studies.In DEFLECT(NCT04586153),167 patients with severe COVID-19 were enroled and randomized to receive three dosages of meplazumab and a placebo.Meplazumab at 0.12 mg/kg,compared to the placebo group,showed clinical benefits in significantly reducing mortality by 83.6%(2.4%vs.14.6%,p=0.0150),increasing the proportion of patients alive and discharged without supplemental oxygen(82.9%vs.70.7%,p=0.0337)and increasing the proportion of patients who achieved sustained clinical improvement(41.5%vs.31.7%).The response rate in the 0.2 mg/kg group was relatively increased by 16.0%compared with the placebo group(53.7%vs.46.3%).Meplazumab also reduced the viral loads and multiple cytokine levels.Compare with the placebo group,the 0.3 mg/kg significantly increased the virus negative rate by 40.6%(p=0.0363)and reduced IL-8 level(p=0.0460);the 0.2 mg/kg increased the negative conversion rate by 36.9%,and reduced IL-4(p=0.0365)and IL-8 levels(p=0.0484).In this study,the adverse events occurred at a comparable rate across the four groups,with no unexpected safety findings observed.In conclusion,meplazumab promoted COVID-19 convalescence and reduced mortality,viral load,and cytokine levels in severe COVID-19 population with good safety profile.

Janus Poly(Vinylidene Fluoride)Membranes with Penetrative Pores for Photothermal Desalination

Solar-driven desalination has been considered as a promising technology for producing clean water through an abundant and pollution-free energy source.It is a critical challenge to reasonably design the porous morphology and the thermal management of photothermal membranes for enabling efficient energy conversion and water production.In this work,a Janus poly(vinylidene fluoride)membrane was fabricated in combination of penetrative pore structure,asymmetric surface wettability with proper thermal management for high-efficiency solar desalination.Highly open and directly penetrative pores achieved by the two-dimensional solvent freezing strategy are considered to provide direct pathways for water and vapor transportation.The unique feature of hydrophobic upper layer/hydrophilic lower layer enables the photothermal membranes to self-float on the water surface and rapidly pump water from the bulk to the surface.The resulting Janus membrane exhibits a satisfactory light absorbance as high as 97%and a photothermal conversion efficiency of 62.8%under one-sun irradiation in a direct contact mode.The solar-to-vapor efficiency rises up to 90.2%with the assistance of a thermal insulator adopted beneath.Both the Janus membrane and the composite setup are able to work efficiently with a high stability in seawater desalination,and the concentration of ion in condensed water is reduced to below 1 ppm.Therefore,Janus membranes with directly penetrative pores and photothermal surfaces shine a light on the development of high-performance solar evaporators for the practical application in solar seawater desalination.

A Novel Missense Mutation in the Spectrin Beta Nonerythrocytic 2 Gene Likely Associated with Spinocerebellar Ataxia Type 5

To the Editor：Spinocerebellar ataxia type 5 （SCA5） is a rare autosomal dominant spinocerebellar ataxia.Mutations in the spectrin beta nonerythrocytic 2 gene （SPTBN2） are known to cause SCA5,six of which have been reported,including three missense mutations and three deletion mutations.