铜-焦脱镁叶绿酸a甲酯的合成及抗肿瘤活性研究实验教学设计

本实验设计合成了铜-焦脱镁叶绿酸a甲酯(Cu-MPPa),用于活性氧(ROS)介导的癌症治疗和消耗谷胱甘肽,并通过类Fenton反应循环产氧维持细胞内高浓度氧。实验过程中考察了Cu-MPPa的活性氧产生能力、氧气产生能力和谷胱甘肽消耗能力等性能。所合成中间体的结构用质谱进行了表征。这个实验综合了有机化学合成、仪器分析化学和生物化学实验,要求由三名学生组成实验小组,大约需要24学时,旨在培养学生综合创新能力、解决复杂问题能力和培养团队合作精神。

基于烯烃碳-氢键活化的碳-碳交叉偶联反应

烯烃是一类非常重要的化合物,人们可以由烯烃通过一系列转化得到复杂的有机分子。本文主要对基于烯烃碳-氢键活化的碳-碳交叉偶联反应进行了详细介绍,基于烯烃的碳-氢键活化,利用铑、钯、钴等过渡金属催化剂,通过碳-碳交叉偶联反应,构建各类碳-碳键。对于烯烃碳-氢键活化反应的介绍,能够丰富和拓展有机化学课程中烯烃的知识点,帮助学生了解有机化学的发展前沿,提高学生学习的积极性和主动性,培养学生的科研素养。

Plutonium utilization in a small modular molten-salt reactor based on a batch fuel reprocessing scheme

A molten salt reactor(MSR)has outstanding features considering the application of thorium fuel,inherent safety,sustainability,and resistance to proliferation.However,fissile material^(233)U is significantly rare at the current stage,thus it is difficult for MSR to achieve a pure thorium-uranium fuel cycle.Therefore,using plutonium or enriched uranium as the initial fuel for MSR is more practical.In this study,we aim to verify the feasibility of a small modular MSR that utilizes plutonium as the starting fuel(SM-MSR-Pu),and highlight its advantages and disadvantages.First,the structural design and fuel management scheme of the SM-MSR-Pu were presented.Second,the neutronic characteristics,such as the graphite-irradiation lifetime,burn-up performance,and coefficient of temperature reactivity were calculated to analyze the physical characteristics of the SM-MSR-Pu.The results indicate that plutonium is a feasible and advantageous starting fuel for a SM-MSR;however,there are certain shortcomings that need to be solved.In a 250 MWth SM-MSR-Pu,approximately 288.64 kg^(233)U of plutonium with a purity of greater than 90% is produced while 978.00 kg is burned every ten years.The temperature reactivity coefficient decreases from -4.0 to -6.5 pcm K^(-1) over the 50-year operating time,which ensures a long-term safe operation.However,the amount of plutonium and accumulation of minor actinides(MAs)would increase as the burn-up time increases,and the annual production and purity of^(233)U will decrease.To achieve an optimal burn-up performance,setting the entire operation time to 30 years is advisable.Regardless,more than 3600 kg of plutonium eventually accumulate in the core.Further research is required to effectively utilize this accumulated plutonium.

Model of self-generated magnetic field generation from relativistic laser interaction with solid targets

Generation of self-generated annular magnetic fields at the rear side of a solid target driven by relativistic laser pulse is investigated by using theoretical analysis and particle-in-cell simulations.The spatial strength distribution of magnetic fields can be accurately predicted by calculating the net flow caused by the superposition of source flow and return flow of hot electrons.The theoretical model established shows good agreement with the simulation results,indicating that the magnetic-field strength scales positively to the temperature of hot electrons.This provides us a way to improve the magnetic-field generation by using a micro-structured plasma grating in front of the solid target.Compared with that for a common flat target,hot electrons can be effectively heated with the well-designed grating size,leading to a stronger magnetic field.The spatial distribution of magnetic fields can be modulated by optimizing the grating period and height as well as the incident angle of the laser pulse.

Growth of ablative Rayleigh-Taylor instability induced by time-varying heat-flux perturbation

The evolution of ablative Rayleigh–Taylor instability(ARTI)induced by single-mode stationary and time-varying perturbations in heat flux is studied numerically in two dimensions.Compared with the stationary case,time-varying heat-flux perturbation mitigates ARTI growth because of the enhanced thermal smoothing induced by the wave-like traveling heat flux.A resonance is found to form when the phase velocity of the heat-flux perturbation matches the average sound speed in the ablation region.In the resonant regime,the coherent density and temperature fluctuations enhance the electron thermal conduction in the ablation region and lead to larger ablation pressure and effective acceleration,which consequently yield higher linear growth rate and saturated bubble velocity.The enhanced effective acceleration offers increased implosion velocity but can also compromise the integrity of inertial confinement fusion shells by causing faster ARTI growth.

基于TCGA数据库角蛋白家族基因对肺腺癌病人预后的预测价值

目的:探讨角蛋白(KRT)家族基因对肺腺癌(LUAD)病人预后的预测价值。方法:RNA测序数据来自LUAD肿瘤和配对正常组织的癌症基因组图谱(TCGA)数据库。采用多变量COX比例风险回归分析评估KRT家族成员基因的预后价值。分析筛选变量以构建风险评分,时间相关ROC曲线评估预测结果。采用使用Nomogram评估个体化预后风险。结果:从差异表达基因中筛选出14个在LUAD肿瘤及癌旁组织中存在显著失衡的KRT基因。ROC曲线分析证实,该14个KRT基因可以作为LUAD诊断的潜在诊断标志物。6个KRT基因与肺癌预后相关,结果显示KRT8和KRT6A是影响LUAD预后的独立危险因素。结论:KRT8和KRT6A可作为LUAD的预后指标,KRT8和KRT6A高表达表明LUAD病人的预后较差。

吡非尼酮对新冠后肺纤维患者的抗纤维化作用研究

目的探讨吡非尼酮对新冠后肺纤维患者抗纤维化作用。方法选择2023年1—6月在本院呼吸与危重症医学科住院及门诊的60例新冠后肺纤维患者为研究对象,按照药物的不同分为观察组和对照组两组,每组各30例。口服吡非尼酮组患者作为观察组;口服乙酰半胱氨酸患者作为对照组。比较两组患者入院时、1个月后、3个月后、6个月后外周血与肺纤维化形成有关的细胞因子(血清KL-6、TGF-β1和TNF-α)、动脉血气,胸部HRCT评分、肺功能指标差异。结果(1)两组患者KL-6、TGF-β1和TNF-α在1个月后、3个月后、6个月后均呈下降趋势,同一时间段观察,与对照组相比,观察组上述指标下降更明显,均具有统计学差异(P<0.05);(2)观察组患者的PaO_(2)、用力肺活量占(FVC)、一氧化碳弥散量占预计值百分比(DLCO%pred)呈逐渐升高趋势,对照组患者的上述指标呈轻微下降趋势,同一时间点,两组比较均具有统计学差异(P<0.05);(3)不同时间点的胸部HRCT评分有差异,从入院1个月开始,两组胸部HRCT评分逐渐下降,两两比较均有统计学差异(P<0.05);两组胸部HRCT评分有差异,观察组组在1个月、3个月及6个月后胸部HRCT评分均明显高于对照组(P<0.05)。结论吡非尼酮可以抑制新冠后肺纤维化患者血中促纤维化因子、改善患者的氧合、肺功能,对新冠后肺纤维化患者具有抗纤维化作用。

大块自体骨原位椎间植骨融合技术在儿童半椎体切除术中的应用研究

目的探讨大块自体骨原位椎间植骨融合技术在儿童半椎体切除术中的应用及效果。方法回顾性分析首都医科大学附属北京儿童医院骨科2018年1月至2020年1月收治的70例因先天性半椎体畸形接受单节段半椎体切除术的患儿临床资料,按照手术方式分为对照组与观察组,对照组35例,采取传统后路半椎体切除植骨融合内固定术;观察组35例,采取后路半椎体切除、前方结构重建(大块自体骨原位椎间植骨)联合后方植骨融合固定术。收集两组患儿临床资料、手术及手术后随访情况。根据术前、术后及随访时站立位全脊柱正侧位X线片,测量相关矢状位和冠状位影像学参数,评估畸形矫正情况及治疗效果;通过随访过程中拍摄的脊柱CT片评估椎间及后方植骨融合情况。结果两组一般资料(性别、身高、年龄、体重、半椎体分布)差异无统计学意义(P>0.05);手术时间、术中出血量、住院日差异无统计学意义(P>0.05),术前冠状面参数(主弯Cobb角、近段代偿弯、远端代偿弯、冠状面平衡、骶骨倾斜角、骨盆倾斜角)及矢状面参数(节段性后凸角、胸椎后凸角、胸腰段后凸角、矢状面平衡、腰椎前凸角)差异亦无统计学意义(P>0.05)。两组术后1个月及末次随访时矢状面和冠状面参数较术前均有明显改善(P>0.05),但组间对比发现,末次随访时观察组主弯Cobb角和节段性后凸角的丢失较对照组明显要少,分别为(0.6±1.7)°比(2.7±2.9)°、(0.6±2.2)°比(3.2±3.9)°,差异均有统计学意义(P<0.05);术后12个月复查CT显示,观察组1级椎间融合率较对照组更高(68.6%比28.6%),差异有统计学意义(P<0.05);两组均无一例发生手术相关并发症。结论大块自体骨原位椎间植骨融合技术可通过前方骨块的支撑与重建,获得满意的椎间融合,矫正效果良好,尤其对于腰椎前凸角度的重建有优势。由于前方椎间的支撑与融合,从长期来看,更利于术后侧后凸角度的维持,可避免矫形角度的过多丢失。

Characteristics of structural loess strength and preliminary framework for joint strength formula

The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests： the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural loess comprehensively and reasonably, a joint strength formula for structural loess was established. This formula comprehensively considers tensile and shear properties. Studies have shown that the tensile strength exhibits a decreasing trend with increasing water content. When the water content is constant, the tensile strength of the structurally intact soil is greater than that ofremolded soil. In the studies, no loss of the originally cured cohesion in the structurally intact soil samples was observed, given that the soil samples did not experience loading disturbance during the uniaxial compressive strength test, meaning there is a high initial structural strength. The results of the conventional triaxial shear strength test show that the water content is correlated with the strength of the structural loess. When the water content is low, the structural properties are strong, and when the water content is high, the structural properties are weak, which means that the water content and the ambient pressure have significant effects on the stress-strain relationship of structural loess. The established joint strength formula of structural loess effectively avoids overestimating the role of soil tensile strength in the traditional theory of Mohr-Coulomb strength.

4例艾滋病患者皮肤卡波氏肉瘤的研究

目的:为了探讨艾滋病皮肤卡波氏肉瘤的临床特征.方法:以南阳医学高等专科学校历年来确诊并搜集到的4例HIV/AIDS合并皮肤卡波氏肉瘤患者为研究对象,从体视学、血液指标、病理学分析病人的临床特征.结果:4例艾滋病皮肤卡波氏肉瘤患者血液CD^(4+)细胞数量显著减少,皮肤呈现红色丘疹、紫色隆起、圆形和卵圆形紫色斑块,真皮层大量梭形细胞增生.结论:艾滋病皮肤卡波氏肉瘤发病症状多种多样,多种检测手段融合有助于深入认识该并发症.

Application of Monte Carlo method to calculate the effective delayed neutron fraction in molten salt reactor

Delayed neutron loss is an important parameter in the safety analysis of molten salt reactors. In this study,to obtain the effective delayed neutron fraction under flow condition, a delayed neutron precursor transport was implemented in the Monte Carlo code MCNP. The moltensalt reactor experiment(MSRE) model was used to analyze the reliability of this method. The obtained flow losses of reactivity for 235 U and 233 U fuels in the MSRE are223 pcm and 100.8 pcm, respectively, which are in good agreement with the experimental values(212 pcm and100.5 pcm, respectively). Then, six groups of effective delayed neutron fractions in a small molten salt reactor were calculated under different mass flow rates. The flow loss of reactivity at full power operation is approximately105.6 pcm, which is significantly lower than that of the MSRE due to the longer residence time inside the active core. The sensitivity of the reactivity loss to other factors,such as the residence time inside or outside the core and flow distribution, was evaluated as well. As a conclusion,the sensitivity of the reactivity loss to the residence time inside the core is greater than to other parameters.

Study on dynamic characteristics of fission products in 2 MW molten salt reactor

In this study,a numerical flow model of the fission products(FPs)in the primary loop system of a molten salt reactor(MSR)was established and solved using Mathematica 7.0.The simulation results were compared with those of the ORIGEN-S program in the static burnup mode,and the deviation was found to be less than 10%,which indicates that the results are in good agreement.Furthermore,the FPs distribution in the primary loop system under normal operating conditions of the 2 MW MSR was quantitatively analyzed.In addition,the distribution phenomenon of the FPs under different flow rate conditions was studied.At the end of life,the FPs activity in the core region(including active region,and upper and lower plenum regions)accounted for 77.3%,and that in the hot leg #1,main pump,hot leg #2,heat exchanger,and cold leg region accounted for 1.2%,16.15%,0.99%,2.5%,and 1.9%,respectively,of the total FPs in the primary loop under normal operating conditions.The proportion of FPs in the core decreased with the increase in flow rate in the range of 2.24-22,400 cm^3 s^-1.The established analytical method and conclusions of this study can provide an important basis for radiation safety design of the primary loop,radioactive source management design,thermal-hydraulic safety analysis,and radiochemical analysis of FPs of 2 MW MSRs.

金属配位聚合物衍生的MoS_(2)在锂硫电池多硫化物催化转化中的应用

锂硫电池在充放电过程中存在多硫化物的氧化还原反应动力学缓慢的现象,导致多硫化锂穿梭效应严重、电池容量衰减等问题。因此,需要高性能的电催化剂来加速锂硫电池中多硫化物的可逆转化。文中以金属配位聚合物为前驱体合成了多孔碳球负载的钴掺杂二硫化钼(pcs-Co@MoS_(2))材料作为多硫化物催化转化的催化剂,极大地提升了锂硫电池的循环性能。以pcs-Co@MoS_(2)为电极材料的电池在充电和放电过程都展现了较低的Tafel斜率(55.47 mV/dec和27.57 mV/dec),表明其较快的反应动力学。恒压放电测试表明,pcs-Co@MoS_(2)组装的电池具有较高的Li_(2)S沉积容量(155.07 mAh/g),体现出其更高的硫利用率。0.5 C倍率下的充放电测试时,pcs-Co@MoS_(2)的初始放电比容量达到了796 mAh/g;在1 C高倍率的循环测试中,电池容量在200圈后保持率为80%,每圈衰减率仅为0.09%。

Analysis of burnup performance and temperature coefficient for a small modular molten‑salt reactor started with plutonium

In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched uranium or plutonium as the starting fuel.By exploiting plutonium as the starting fuel and thorium as the fertile fuel,the high-purity^(233)U produced can be separated from the spent fuel by fluorination volatilization.Therefore,the molten salt reactor started with plutonium can be designed as a^(233)U breeder with the burning plutonium extracted from a pressurized water reactor(PWR).Combining these advantages,the study of the physical properties of plutonium-activated salt reactors is attractive.This study mainly focused on the burnup performance and temperature reactivity coefficient of a small modular molten-salt reactor started with plutonium(SM-MSR-Pu).The neutron spectra,^(233)U production,plutonium incineration,minor actinide(MA)residues,and temperature reactivity coefficients for different fuel salt volume fractions(VF)and hexagon pitch(P)sizes were calculated to analyze the burnup behavior in the SM-SMR-Pu.Based on the comparative analysis results of the burn-up calculation,a lower VF and larger P size are more beneficial for improving the burnup performance.However,from a passive safety perspective,a higher fuel volume fraction and smaller hexagon pitch size are necessary to achieve a deep negative feedback coefficient.Therefore,an excellent burnup performance and a deep negative temperature feedback coefficient are incompatible,and the optimal design range is relatively narrow in the optimized design of an SM-MSR-Pu.In a comprehensive consideration,P=20 cm and VF=20%are considered to be relatively balanced design parameters.Based on the fuel off-line batching scheme,a 250 MWth SM-MSR-Pu can produce approximately 29.83 kg of ^(233)U,incinerate 98.29 kg of plutonium,and accumulate 14.70 kg of MAs per year,and the temperature reactivity coefficient can always be lower than−4.0pcm/K.

Application system and data description of the China Seismo-Electromagnetic Satellite

The China Seismo-Electromagnetic Satellite, launched into orbit from Jiuquan Satellite Launch Centre on February 2 nd, 2018, is China's first space satellite dedicated to geophysical exporation. The satellite carries eight scientific payloads including high-precision magnetometers to detect electromagnetic changes in space, in particular changes associated with global earthquake disasters. In order to encourage and facilitate use by geophysical scientists of data from the satellite's payloads, this paper introduces the application systems developed for the China Seismo-Electromagnetic Satellite by the Institute of Crustal Dynamics, China Earthquake Administration;these include platform construction, data classification, data storage, data format, and data access and acquisition.

Study on neutronics design of ordered-pebble-bed fluoride-salt- cooled high-temperature experimental reactor

This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements.Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means(-6980 to -3651 pcm) and negative temperature coefficient(-6.32 to -3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient,have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including ~6Li depletion and tritium production.

Th–U cycle performance analysis based on molten chloride salt and molten fluoride salt fast reactors

The recent development of molten salt fast reactors has generated a renewed interest in them. As compared to traditional solid fuel fast neutron systems, it has many unique advantages, e.g., lower fissile inventory,no initial criticality reserve, waste reduction, and a simplified fuel cycle. It has been recognized as an ideal reactor for achieving a closed Th–U cycle. Based on the carrier salt, molten salt fast reactors could be divided into either a molten chloride salt fast reactor(MCFR) or a molten fluoride salt fast reactor(MFFR);to compare their Th–U cycle performance, the neutronic parameters in a breeding and burning(B&B) transition scenario were studied based on similar core geometry and power. The results demonstrated that the required reprocessing rate for an MCFR to achieve self-breeding was lower than that of an MFFR.Moreover, the breeding capability of an MCFR was better than that of an MFFR;at a reprocessing rate of 40 L/day,using LEU and Pu as start-up fissile materials, the doubling time(DT) of an MFFR and MCFR were 88.0 years and 48.0 years, and 16.5 years and 16.2 years, respectively.Besides, an MCFR has lower radio-toxicity due to lower buildup of fission products(FPs) and transuranium(TRU),while an MFFR has a larger, delayed neutron fraction with smaller changes during the entire operation.

Examples of unusual ionospheric observations by the CSES prior to earthquakes

The CSES(China seismic electromagnetic satellite) was launched on February 2, 2018 in a circular polar orbit at an altitude of～507 km. One of the main objectives of CSES is to search for and characterize ionospheric perturbations that can be associated with seismic activities, to better understand the generation mechanism of such perturbations. Its scientific payload can measure a broad frequency range of electromagnetic waves and some important plasma parameters. This paper is a first-hand study of unusual observations recorded by the CSES over seismic regions prior to four earthquakes with M >7.0 since the satellite's launch. CSES detectors measured irregularities near the epicenter of these four earthquakes. It is already clear that data from instruments onboard the CSES will be of significant help in studies of characteristics of ionospheric perturbations related to earthquakes and their generation mechanisms.

The Langmuir Probe onboard CSES: data inversion analysis method and first results

The Langmuir Probe(LAP), onboard the China Seismo-Electromagnetic Satellite(CSES), has been designed for in situ measurements of bulk parameters of the ionosphere plasma, the first Chinese application of in-situ measurement technology in the field of space exploration. The two main parameters measured by LAP are electron density and temperature. In this paper, a brief description of the LAP and its work mode are provided. Based on characteristics of the LAP, and assuming an ideal plasma environment, we introduce in detail a method used to invert the I-V curve; the data products that can be accessed by users are shown. Based on the LAP data available, this paper reports that events such as earthquakes and magnetic storms are preceded and followed by obvious abnormal changes. We suggest that LAP could provide a valuable data set for studies of space weather, seismic events, and the ionospheric environment.

Study on the production characteristics of(131)^I and(90)^Sr isotopes in a molten salt reactor

The production of radionuclides(90)^Sr and(131)^I in molten salt reactors is an attractive option to address the global shortage of radionuclides.This study evaluated the production characteristics of(90)^Sr and(131)^I in a modular molten salt reactor,such as equilibrium time,yield,and cooling time of isotopic impurities.The fuel burn-up of a small modular molten salt reactor was analyzed by the Triton module of the scale program,and the variation in the fission yields of the two nuclides and their precursors with burn-up time.The yield of(131)^I and~(131)Te has been increasing during the lifetime.131 I has an equilibrium time of about 40 days,a saturation activity of about 40,300 TBq,and while~(131)Te takes 250 min to reach equilibrium,the equilibrium activity was about 38,000 TBq.The yields of90 Sr and~(90)Kr decreased gradually,the equilibrium time of90 Kr was short,and(90)^Sr could not reach equilibrium.Based on the experimental data of molten salt reactor experiment,the amount of nuclide migration to the tail gas and the corresponding cooling time of the isotope impurities under different extraction methods were estimated.Using the HF-H_2 bubbling method,3.49×10^(5)TBq of(131)^I can be extracted from molten salt every year,and after13 days of cooling,the impurity content meets the medical requirements.Using the electric field method,1296 TBq of(131)^I can be extracted from the off-gas system(its cooling time is 11 days)and 109 TBq of(90)^Sr.The yields per unit power for(131)^I and(90)^Sr is approximately 1350 TBq/MW and 530 TBq/MW,respectively,which shows that molten salt reactors have a high economic value.