薄层色谱法分离菠菜色素实验的绿色改进

薄层色谱法(TLC)是一种快速分离和定性分析少量物质的常用实验技术,在原有薄层色谱法分离菠菜色素的实验中,所选择的展开剂中使用大量一类致癌物苯,实验过程中经常出现斑点拖尾、色素点分离不清晰等问题.为了避免使用致癌物苯且优化实验效果,选择非极性溶剂石油醚、正己烷、环己烷和极性溶剂乙醇、乙酸乙酯、丙酮多次组合进行薄层色谱分离菠菜色素实验,结果显示:当展开剂为正己烷-丙酮体积比为7:3时分离效果最好,胡萝卜素、脱镁叶绿素、叶绿素a、叶绿素b、叶黄素的Rf值分别为0.92,0.85,0.42,0.28,0.72,色素斑点完整、清晰度好.对该实验方法进行验证,结果显示其重现性和耐用性良好.

Numerical Studies of Magnetic Reconnection and Heating Mechanisms for the Ellerman Bomb

An Ellerman Bomb(EB)is a kind of small scale reconnection event,which is ubiquitously formed in the upper photosphere or the lower chromosphere.The low temperature(<10,000 K)and high density(~1019–1022)plasma there makes the magnetic reconnection process strongly influenced by partially ionized effects and radiative cooling.This work studies the highβmagnetic reconnection near the solar temperature minimum region based on high-resolution 2.5D magnetohydrodynamics simulations.The time-dependent ionization degree of hydrogen and helium are included to realize more realistic diffusivities,viscosity and radiative cooling in simulations.Numerical results show that the reconnection rate is smaller than 0.01 and decreases with time during the early quasi-steady stage,then sharply increases to a value above 0.05 in the later stage as the plasmoid instability takes place.Both the large value ofηen(magnetic diffusion caused by the electron-neutral collision)and the plasmoid instability contribute to the fast magnetic reconnection in the EB-like event.The interactions and coalescence of plasmoids strongly enhance the local compression heating effect,which becomes the dominant mechanism for heating in EBs after plasmoid instability appears.However,the Joule heating contributed byηen can play a major role to heat plasmas when the magnetic reconnection in EBs is during the quasi-steady stage with smaller temperature increases.The results also show that the radiative cooling effect suppresses the temperature increase to a reasonable range,and increases the reconnection rate and generation of thermal energy.

一种EtherCAT主站存取网络结构设计

针对EtherCAT主站存储和读取网络结构信息较为复杂的问题,设计一种先将网络结构信息与源代码分离,之后再将这些信息集成到可执行程序文件内部的方法。该方法在网络设计阶段通过配置软件将从站型号信息、型号索引、设备选型信息保存为文本文件;在软件构建阶段将上述文件与源代码一并处理生成程序;程序运行后通过型号索引直接寻址查询到设计方案中从站的ID,通过ID、从站数量对比实际部署的网络结构与所设计的方案是否一致。经测试验证,程序中存储的从站型号信息、型号索引及从站选型信息完整正确;在线检查网络结构功能可高效查询到方案中每个节点的型号信息并对比型号是否匹配。该方法实现简单且运行高效,有效降低主站和配套的网络结构设计工具的开发难度,同时改善了EtherCAT主站产品的用户体验和经济效益。

Effect of ephedrine hydrochloride on regulation of body fluid metabolism and AQP1 and AQP2 in a rabbit model of mechanical ventilation

Objective:Ephedrine hydrochloride(EH)is a major component from Ephedra sinica STAPF,which is used as a traditional Chinese herbal medicine.This study was designed to investigate the effect of EH on water metabolism and further explore the relevant signaling pathway of body fluid regulation in“lung governing regulation of water passage”using a rabbit model of mechanical ventilation.The molecular mechanism of the EH effect in the kidney was also investigated.Methods:Rabbits were randomly divided into a control group,model group,EH group,and dexmedetomidine hydrochloride(DH)group.Urine volume was measured by the intubation method and pathologic changes in lung and renal tissue were measured by hematoxylin and eosin staining.Nitric oxide(NO)production in lung,serum,and kidney were analyzed using chemical methods.An ELISA was used to analyze angiotensin II(Ang II),antidiuretic hormone(ADH),prostaglandin E2(PGE2),atrial natriuretic peptide(ANP),and endothelin-1(ET-1)levels in the lung,serum,and kidney.Aquaporin-1(AQP1)and aquaporin-2(AQP2)mRNA and protein expression in the kidney was determined using qRT-PCR and immunohistochemistry.Results:EH significantly inhibited the decrease in the total urine volume in the third and fourth stages,and displayed significant regulatory effects on NO,Ang II,ADH,PGE2,ANP,and ET-1 in serum,lung,and renal tissues compared with the model group.In the kidney,AQP1 and AQP2 mRNA and protein expression in the EH group were remarkably downregulated compared with the model group.Conclusion:EH exerted a regulatory effect on water metabolism by diffusing the lung and increased urine volume in the rabbit model,which was consistent with the decrease in kidney AQP1 and AQP2 expression levels that led to an increase in urine volume.EH could assist with DH to exert a protective effect on the clinical application of mechanical ventilation.

Effect of mechanical ventilation on urine volume and expression of aquaporins in rabbits

Objective:To explore biological mechanisms underlying the traditional Chinese medicine theory of 'lung governing the regulation of water passage' by observing effects of mechanical ventilation on urine volume and related bioactive substances.Methods:A total of 16 male rabbits were randomly divided into control and lung expansion model groups (n =8 per group),which were examined during the following four respiratory intervention stages (10 minutes each):(1) free breathing without any respiratory intervention;(2) lung expansion induced by mechanical ventilator;(3) free breathing without ventilator intervention;(4) cutting of bilateral sympathetic,vagus,and depressor nerves with mechanical ventilation.Data for breathing rate,blood pressure,and urine drops were recorded with a Medlab data acquisition system.Levels of nitric oxide (NO),antidiuretic hormone (ADH),endothelin 1 (ET-1),angiotensin Ⅱ (AngⅡ),prostaglandin E2 (PGE2),and atrial natriuretic peptide (ANP) were detected in lung tissue,kidney tissue,and serum by enzyme-linked immunosorbent assay.Protein expression of aquaporins 1 and 2 (AQP1 and AQP2) was detected in kidney tissue by immunohistochemistry,while Aqp1 mRNA and Aqp2 mRNA levels in kidney tissue were detected by real-time quantitative polymerase chain reaction.Histopathological changes in lung and kidney tissues were examined by hematoxylin and eosin staining.Results:Compared with the control group,number of urine drops during the second and fourth stages is significantly decreased in the model group (P <.05).In addition,NO and PGE2 content in lung and kidney tissues was significantly decreased in the model group (P <.05).ANP content in model group lung and kidney tissues was significantly increased (P <.05),while ET-1 content in these tissues was significantly decreased (P <.05).AngⅡ content in kidney tissue was significantly decreased in the model group (P <.05),while serum AngⅡ content of the animals was significantly increased (P <.05).Expression of AQP1 and AQP2 proteins in kidney tissue was significantly higher in the model group than in the control group (P <.05).No obvious histopathological changes were observed in lung or kidney tissues of animals in either group.Conclusions:Mechanical ventilation reduced urine volume,increased expression of AQP1 and AQP2 in kidney tissue,and altered levels of NO,ADH,ET-1,AngⅡ,PGE2,and ANP in lung tissue,kidney tissue,and serum.These results provide an experimental basis for preliminary studies of mechanisms under pinning the theory of 'lung governing the regulation of water passage'.

Thermal hazard and mechanism study of 5-(4-Pyridyl)tetrazolate(H4-PTZ)

Thermal decomposition experiment of 5-(4-Pyridyl)tetrazolate(H4-PTZ)was carried out.The heat flow curve and reaction rate data under different heating rates were obtained.The characteristic parameters were obtained.The apparent activation energy for each individual reaction was calculated by applying different methods.On this basis,the Malek method was used to predict the most probable mechanism function of thermal decomposition reaction of H4-PTZ.The thermal safety parameters,including self-accelerating decomposition temperature,hot spot fire temperature and thermal explosion critical temperature were also predicted.The activation enthalpy,activation entropy,and activation Gibbs free energy of H4-PTZ are calculated.Gaussian16 program was used to optimize the molecular structure,search the transition state and calculate the intrinsic reaction coordinates of H4-PTZ.The most probable decomposition path of H4-PTZ was found,and the activation energy calculated by experiment was compared with that calculated by the theory.

Single-crystalline hole-transporting layers for efficient and stable organic light-emitting devices

Efficient charge-carrier injection and transport in organic light-emitting devices(OLEDs)are essential to simultaneously achieving their high efficiency and long-term stability.However,the charge-transporting layers(CTLs)deposited by various vapor or solution processes are usually in amorphous forms,and their low charge-carrier mobilities,defectinduced high trap densities and inhomogeneous thickness with rough surface morphologies have been obstacles towards high-performance devices.Here,organic single-crystalline(SC)films were employed as the hole-transporting layers(HTLs)instead of the conventional amorphous films to fabricate highly efficient and stable OLEDs.The highmobility and ultrasmooth morphology of the SC-HTLs facilitate superior interfacial characteristics of both HTL/electrode and HTL/emissive layer interfaces,resulting in a high Haacke’s figure of merit(FoM)of the ultrathin top electrode and low series-resistance joule-heat loss ratio of the SC-OLEDs.Moreover,the thick and compact SC-HTL can function as a barrier layer against moisture and oxygen permeation.As a result,the SC-OLEDs show much improved efficiency and stability compared to the OLEDs based on amorphous or polycrystalline HTLs,suggesting a new strategy to developing advanced OLEDs with high efficiency and high stability.

微波消解-原子吸收光谱法测定儿童牙刷刷毛中重金属元素的含量

重金属元素对人体的新陈代谢有严重的危害作用[1],影响人体的正常生理过程,尤其是在儿童成长发育阶段,摄入过量的重金属元素会影响儿童的智力和身体发育[2],降低儿童的免疫力,因此人们对儿童用品中重金属元素的含量越来越重视。儿童牙刷是儿童重要的生活用品,刷毛中通常含有铬、镉、铅、铜、铁等重金属元素,因此建立一种准确测定儿童牙刷刷毛中重金属元素含量的方法具有重要意义[3]。

基于CDIO模式的实践教学改革——以“原子吸收光谱分析实验”为例

以学生综合能力培养为目的,基于CDIO工程教学模式,重新构建原子吸收光谱分析实验课程教学体系。该体系立足于学生为主体,以实验项目的构思、设计、实施、运行四大板块为依托,对原子吸收光谱分析实验课程教学进行改革,培养学生的理论知识、个人能力、团队协作能力、工程实践能力等多种能力。

基于双dq变换正负序提取及锁相环的FPGA实现

对于并网型电能质量治理设备,如有源电力滤波器(APF),为了实现对电能质量的检测与治理功能,需要对三相电压基波的正负序进行快速准确提取。当电网电压发生不对称、畸变等情况时,能否快速准确获得基波电压的频率和相位信息将会大大影响电能质量治理设备运行性能。文中依据同步旋转坐标变换理论,采用双dq变换方法,通过低通滤波器(LPF)处理,实现对基波电压的正负序提取,在此基础上引入负反馈控制理论实现锁相环功能。依据此理论使用FPGA实现基波电压正负序提取及锁相环功能,经测试表明文中所设计的系统能够在三相电压出现不对称、畸变等情况时,快速准确实现基波电压正负序提取、以及基波频率和相位的锁定,能够满足有源电力滤波器对于电压频率、相位实时检测与设备控制保护的使用需求。

Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM: To investigate the signaling pathways implicated in phosphatidylethanolamine (PE)-induced apoptosis of human hepatoma HepG2 cells. METHODS: Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle, apoptosis and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE. RESULTS: PE inhibited the growth of HepG2 cells in a doseand timedependent manner. It did notaffect the cell cycle, but induced apoptosis. PE significantly decreased ΔΨm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a doseand time-dependent manner. CONCLUSION: Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.

Apoptosis of pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid in combination with horseradish peroxidase

AIM： To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid （IAA） in combination with horseradish peroxidase （HRP）. METHODS： BXPC-3 cells derived from human pancreatic cancer were exposed to 40 or 80 μmol/L IAA and 1.2 μg/mL HRP at different times. Then, Mn- assay was used to detect the cell proliferation. Flow cytometry was performed to analyze cell cycle. Terminal deoxynucleotidyl transferasemediated dUTP nick end labeling assay was used to detect apoptosis. 2,7-Dichlorofluorescin diacetate uptake was measured by confocal microscopy to determine free radicals. Level of malondialdehyde （MDA） and activity of superoxide dismutase （SOD） were measured by biochemical methods. RESULTS： IAA/HRP initiated growth inhibition of BXPC-3 cells in a dose- and time-dependent manner. Flow cytometry revealed that the cells treated for 48 h were arrested at G1/G0. After exposure to 80 μmol/L IAA plus 1.2 μg/mL HRP for 72 h, the apoptosis rate increased to 72.5‰, which was nine times that of control. Content of MDA and activity of SOD increased respectively after treatment compared to control. Meanwhile, IAA/HRP stimulated the formation of free radicals. CONCLUSION： The combination of IAA and HRP can inhibit the growth of human pancreatic cancer BXPC-3 cells in vitro by inducing apoptosis.

基于VxWorks的全数字通讯接口直流输电极控系统设计

为实现对基于电网换相换流器(LCC)拓扑结构的直流输电换流站的有效控制和监视,文中设计了一种基于VxWorks嵌入式平台开发的全数字化通讯接口直流输电极控系统。该系统采用Vx Works嵌入式实时操作系统开发应用程序,并实现了PIC闭环控制算法和自动控制选择功能,可实现对换流站进行百微秒级周期的实时控制和监视。此外,该系统采用Profibus、IEC 60044-8—2002及GOOSE等数字通讯协议,实现了对外接口完全数字化的高可靠性控制设备。该控制系统可应用于中低压直流输配电领域,经过±20 k V/50 A背靠背直流输电系统模型的性能试验验证,满足数据传输实时性、可靠性需求和控制规范要求。

酒石酸布托啡诺在无痛胃镜中的应用

目的观察布托啡诺联合丙泊酚和依托咪酯在无痛胃镜中的应用效果及不良反应。方法选取2019年1-4月西部战区总医院内镜中心行无痛胃镜检查的成人患者100例,随机分为对照组和试验组,每组各50例。对照组注射舒芬太尼5μg、丙泊酚1 mg/kg和依托咪酯0.2 mg/kg;试验组注射布托啡诺0.3 mg、丙泊酚1 mg/kg和依托咪酯0.2 mg/kg。观察患者呛咳、术中体动发生率,术中氧饱和度低于90%的发生率;患者内镜检查时间、术后睁眼时间及离室时间;患者术后不良反应发生情况:恶心、呕吐、头晕、嗜睡;以及患者诱导前(T0)、术中(T1)、苏醒时(T2)和离室时(T3)的平均动脉压(MAP)、心率(HR)、脉搏血氧饱和度(SpO2)。结果两组患者术中丙泊酚、依托咪酯用量以及在T0、T1、T2、T3相同时间点MAP、HR、SpO2比较,差异无统计学意义(P>0.05);两组患者组内在T1、T2、T3与T0的MAP比较差异有统计学意义(P<0.05),两组患者组内的HR在T3与T0比较差异有统计学意义(P<0.05);两组患者检查时间、术后睁眼时间、离室时间及术后总的不良反应发生率比较,差异无统计学意义(P>0.05);对照组患者术后恶心呕吐发生率明显高于试验组(P<0.05)。结论布托啡诺联合丙泊酚和依托咪酯能够安全用于无痛胃镜检查,可替代舒芬太尼,减少患者术后恶心呕吐的发生率,便于麻醉药品管理。

基于模块化风冷换流阀的中压直流输电系统

为探索中国国内中压直流输电(MVDC)市场的未来,文中通过已经建成的德国亚琛大学的10 kV直流配电工程案例,重点介绍了中国西电集团完全自主化制造、具有全部自主知识产权的一个中压直流输电系统。该系统采用了完全自主化设计的模块化风冷光触发晶闸管(LTT)换流阀、箔绕干式换流变压器及完全数字化接口的控制保护系统。整个系统紧凑简洁、可靠性高、便于维护,已经具备了进行示范工程应用的条件。此外,还对中压直流输电的技术经济性进行了初步分析,结果说明针对交流配网增容受限的城市负荷中心、远距离电缆输电区域、具有分布电源或大容量直流负载的负荷区域以及中压直流输电都具有相当的竞争力。

胰岛素鼻内给药与术后谵妄的进展

术后谵妄(POD)是常见的术后并发症,主要表现为思维紊乱、定向力障碍、注意力不集中、昼夜颠倒、意识改变等症状,可导致术后并发症增多,围术期死亡率增高。目前,POD的发病原因尚未明确,也无安全有效的防治方法。胰岛素鼻内给药是与脑能量代谢异常相关的认知障碍的重要治疗方法,近年来得到广泛关注。脑中胰岛素浓度增高可改善学习记忆功能,特别是海马依赖性(陈述性)记忆,鼻内给药是增加脑中胰岛素的主要方式。基于POD现有的病理生理机制,鼻内给予胰岛素可能通过增加脑部血流量、减轻炎症反应、改善睡眠-觉醒周期的紊乱、降低τ蛋白过度磷酸化、减少Aβ的沉积等途径预防和减少POD的发生。

The Ellerman bomb and ultraviolet burst triggered successively by an emerging magnetic flux rope

Ellerman bombs(EBs)and ultraviolet(UV)bursts are common brightening phenomena,which are usually generated in the low solar atmosphere of emerging flux regions.In this paper,we have investigated the emergence of an initial un-twisted magnetic flux rope based on three-dimensional(3 D)magneto-hydrodynamic(MHD)simulations.The EB-like and UV burst-like activities successively appear in the U-shaped part of the undulating magnetic fields triggered by the Parker instability.The EB-like activity starts to appear earlier and lasts for about 80 seconds.Six minutes later,a much hotter UV burstlike event starts to appear and lasts for about 60 seconds.Along the direction vertical to the solar surface,both the EB and UV burst start in the low chromosphere,but the UV burst extends to a higher altitude in the up chromosphere.The regions with apparent temperature increase in the EB and UV burst are both located inside the small twisted flux ropes generated in magnetic reconnection processes,which are consistent with the previous 2 D simulations that most hot regions are usually located inside the magnetic islands.However,the twisted flux rope corresponding to the EB is only strongly heated after it floats up to an altitude much higher than the reconnection site during that period.Our analyses show that the EB is heated by the shocks driven by the strong horizontal flows at two sides of the U-shaped magnetic fields.The twisted flux rope corresponding to the UV burst is heated by the driven magnetic reconnection process.

Numerical studies of the Kelvin-Hemholtz instability in a coronal jet

Kelvin-Hemholtz（K-H）instability in a coronal EUV jet is studied via 2.5D MHD numerical simulations.The jet results from magnetic reconnection due to the interaction of the newly emerging magnetic field and the pre-existing magnetic field in the corona.Our results show that the Alfv e′n Mach number along the jet is about 5–14 just before the instability occurs,and it is even higher than 14 at some local areas.During the K-H instability process,several vortex-like plasma blobs with high temperature and high density appear along the jet,and magnetic fields have also been rolled up and the magnetic configuration including anti-parallel magnetic fields forms,which leads to magnetic reconnection at many X-points and current sheet fragments inside the vortex-like blob.After magnetic islands appear inside the main current sheet,the total kinetic energy of the reconnection outflows decreases,and cannot support the formation of the vortex-like blob along the jet any longer,then the K-H instability eventually disappears.We also present the results about how the guide field and flux emerging speed affect the K-H instability.We find that a strong guide field inhibits shock formation in the reconnecting upward outflow regions but helps secondary magnetic islands appear earlier in the main current sheet,and then apparently suppresses the K-H instability.As the speed of the emerging magnetic field decreases,the K-H instability appears later,the highest temperature inside the vortex blob gets lower and the vortex structure gets smaller.

GroupNet:Learning to group corner for object detection in remote sensing imagery

Due to the attractive potential in avoiding the elaborate definition of anchor attributes,anchor-free-based deep learning approaches are promising for object detection in remote sensing imagery.Corner Net is one of the most representative methods in anchor-free-based deep learning approaches.However,it can be observed distinctly from the visual inspection that the Corner Net is limited in grouping keypoints,which significantly impacts the detection performance.To address the above problem,a novel and effective approach,called Group Net,is presented in this paper,which adaptively groups corner specific to the objects based on corner embedding vector and corner grouping network.Compared with the Corner Net,the proposed approach is more effective in learning the semantic relationship between corners and improving remarkably the detection performance.On NWPU dataset,experiments demonstrate that our Group Net not only outperforms the Corner Net with an AP of 12.8%,but also achieves comparable performance to considerable approaches with 83.4%AP.

HR部门顾客关系管理与企业可持续经营绩效关系研究

以山东、上海等地35家企业内的245对员工一中高层管理者配对样本为调研对象,研究HR部门顾客关系管理与企业可持续经营绩效的关系。结果表明,HR部门的战略应变能力和可持续经营理念均与经济绩效正相关;HR部门的战略应变能力、雇主吸引力、监管机制以及可持续经营理念均与文化绩效正相关;HR部门的内部营销组合、战略应变能力和监管机制均与社会绩效呈正相关关系;HR部门的战略应变能力和可持续经营理念均与生态绩效呈正相关关系。