A review of ^(17)O isotopic labeling techniques for solid-state NMR structural studies of metal oxides in lithium-ion batteries

Recent advances in utilizing ^(17)O isotopic labeling methods for solid-state nuclear magnetic resonance(NMR)investigations of metal oxides for lithium-ion batteries have yielded extensive insights into their structural and dynamic details.Herein,we commence with a brief introduction to recent research on lithium-ion battery oxide materials studied using ^(17)O solid-state NMR spectroscopy.Then we delve into a review of ^(17)O isotopic labeling methods for tagging oxygen sites in both the bulk and surfaces of metal oxides.At last,the unresolved problems and the future research directions for advancing the ^(17)O labeling technique are discussed.

High-temperature thermal stability of C/C−ZrC−SiC composites via region labeling method

To investigate the thermal stability of ceramic-matrix composites,three kinds of C/C−ZrC−SiC composites with different Zr/Si molar ratios were synthesized by reactive melt infiltration.Employing region labeling method,the high-temperature thermal stability of the composites was systematically studied by changing the temperature and holding time of thermal treatment.Results show that the mass loss rate of low Si composites has a growth trend with increasing temperature,and a crystal transformation from β-SiC toα-SiC occurs in the composites.In the calibrated area,SiC phase experiences Ostwald ripening and volume change with location migration,while ZrC phase experiences a re-sintering process with diffusion.Moreover,it is found that increasing temperature has a more obvious effect on the thermal stability than extending holding time,which is mainly attributed to the faster diffusion rate of atoms.

First-Arrival Picking Method for Active Source Data with Ocean Bottom Seismometers Based on Spatial Waveform Variation Characteristics

The precision and reliability of first-arrival picking are crucial for determining the accuracy of geological structure inversion using active source ocean bottom seismometer(OBS)refraction data.Traditional methods for first-arrival picking based on sample points are characterized by theoretical errors,especially in low-sampling-frequency OBS data because the travel time of seismic waves is not an integer multiple of the sampling interval.In this paper,a first-arrival picking method that utilizes the spatial waveform variation characteristics of active source OBS data is presented.First,the distribution law of theoretical error is examined;adjacent traces exhibit variation characteristics in their waveforms.Second,a label cross-correlation superposition method for extracting highfrequency signals is presented to enhance the first-arrival picking precision.Results from synthetic and field data verify that the proposed approach is robust,successfully overcomes the limitations of low sampling frequency,and achieves precise outcomes that are comparable with those of high-sampling-frequency data.

THE DIVERGENT PROJECTIONS OF PERIPHERAL PROCESSES OF SUBSTANCE P-CONTAINING SPINAL GANGLIONIC NEURONS——Tri-labeled method of combining fluorescein tracing and immunocytochemistry

The development of fluorescien double labeling method in recent years,has identified the peripheral processes of spinal ganglionic neurons project divergently to the somatic and visceral areas,but the chemical nature of these neurons remains unknown.For this reason,we developed a tri-labeled method of combining fluorescein tracing and immunocytochemistry to clarify this problem.

Syntheses of Fe-Ni Magnetic Nanoparticles and Their Applications on Biologic Labeling

In this study,we compared FeNi alloy magnetic nanoparticles(MNPs) prepared by either combustion or chemical precipitation methods.We found that the FeNi MNPs generated by combustion method have a rather high saturation magnetization Ms of ～180 emu/g and a coercivity field Hc of near zero.However,the alloy nanoparticles are easily aggregated and are not well dispersive such that size distribution of the nanoparticle clusters is wide and clusters are rather big(around 50～700 nm).To prepare a better quality and well dispersed Fe-Ni MNPs,we also developed a thermal reflux chemical precipitation method to synthesize FeNi3 alloy MNPs.The precursor chemicals of Fe(acac)3 and Ni(acac)2 in a molecular ratio of 1:3 reacted in octyl ether solvent at the boiling point of solvent(～300 ℃) by the thermal reflux process.The 1,2-hexadecandiol and tri-n-octylphosphine oxide(TOPO) were used as reducer and surfactant,respectively.The chemically precipitated FeNi3 MNPs are well dispersed and have well-controlled particle sizes around 10～20 nm with a very narrow size distribution(±1.2 nm).The highly monodispersive FeNi3 MNPs present good uniformity in particle shape and crystallinity on particle surfaces.The MNPs exhibit well soft magnetism with saturation magnetization of ～61 emu/g and Hc～0.The biomedically compatible FeNi MNPs which were coated with biocompatible polyethyleneimine(PEI) polymer were also synthesized.We demonstrated that the PEI coated FeNi MNPs can enter the mammalian cells in vitro and can be used as a magnetic resonance imagine(MRI) contrast agent.The results demonstrated that FeNi MNPs potentially could be applied in the biomedical field.The functionalized magnetic beads with biocompatible polymer coated on MNPs are also completed for biomedical applications.

一种半监督金融事件多标签分类方法

随着数字金融服务业的不断发展,互联网和金融服务系统积累了海量文本数据,对金融文本中描述的金融事件自动分类是金融科技的现实需求,也是自然语言处理和机器学习领域广泛关注的方向。目前,深度学习方法已在文本分类中广泛应用,针对文本数据中的金融事件多标签分类中存在的已标注数据缺少、已有深度学习方法消耗资源大以及现有方法未利用金融事件文本的具体特点等问题,通过采用ALBERT和TextCNN等表示工具,引入主体词注意力机制,提出了一种半监督金融事件多标签分类方法。首先,通过无监督数据增强(Unsupervised data augmentation,UDA)方法缓解标注数据量不足的问题;其次,引入了主体词注意力机制,使用ALBERT动态词向量表征方法对文本中的词进行表示;然后,利用TextCNN对文本进行综合语义表示;最后,分别采用交叉熵和KL散度度量标记数据和无标记数据的损失来训练模型。在金融文本数据集上验证了本文所提方法的有效性。

基于一致性正则化的深度偏标记半监督学习方法

大部分偏标记学习方法假设所有训练样本都具有候选标记集,然而在许多现实场景下存在大量无标记样本.如何同时利用偏标记和无标记样本所隐含的信息构建学习模型,是偏标记半监督学习研究的关键问题.针对只含有少量标记样本、偏标记样本和大量无标记样本的图像分类问题,运用一致性正则化方法和伪标记方法建立深度学习模型.对于偏标记和无标记样本,基于其弱增强的输出结果生成伪标记,且偏标记样本的伪标记限制于其候选标记集中.研究设计了新的损失函数,包含3个损失项,可以同时利用数据中的监督信息、弱监督信息和无监督信息.为了提高参与训练过程样本的可靠性,只选择高置信度伪标记的样本来计算两种增强后的输出交叉熵损失.实验结果说明,该方法(CR-SSPL)比现有半监督学习SOTA方法FlexMatch和偏标记学习代表方法具有更高的精度和稳定性,收敛速度也有明显提升.

基于^(13)C同位素标记法探究连作对丹参生长及光合碳分配的影响

以1年龄盆栽丹参为研究对象,设置^(13)C脉冲标记处理与^(12)C正常处理,应用^(13)C脉冲标记法研究连作与非连作丹参光合碳分配规律,比较植株标记40 d后的形态学与理化指标差异,分析丹参地上部、根部以及根际土壤碳的^(13)C丰度、碳同位素比率、^(13)C原子百分比以及单位干重样品的^(13)C总量,以明确连作对丹参生长与光合作用的影响机理。结果表明,连作条件下,丹参各部分生物量与叶绿素含量明显下降,抗氧化酶活性升高;有效成分中的丹参酮Ⅰ、丹参酮Ⅱ_(A)、二氢丹参酮Ⅰ以及迷迭香酸含量均降低;连作显著影响^(13)C-光合碳分配比例,非连作丹参地上部、根部以及根际土壤中^(13)C-光合碳比率分别为27.14%、72.80%和0.06%,连作丹参为59.38%、40.59%和0.03%。综上,连作后,丹参生长发育与次生代谢受到明显影响;光合产物向地下部的转移能力降低,导致连作丹参根部生长发育受到明显抑制;丹参光合作用的强弱是反映丹参生长状况的重要指标。

激励谱形对包装标签表面油墨振动磨损的影响

围绕运输过程中箱装瓶形产品表面标签的摩擦损伤,建立标签油墨振动磨损定量评价方法,研究振动激励谱形对包装系统响应及标签油墨振动磨损的影响,并分析导致标签油墨振动磨损差异的影响因素。结果表明:标签磨损程度可通过油墨转移量的单位像素平均灰度值定量评价;由于包装系统的非线性振动传递特性,垂直振动激励会引起侧向振动响应,使包装内产品与包装侧壁间相互挤压,在振动条件下会发生相互摩擦从而导致标签磨损;由于包装系统的窄带滤波响应特性,在振动总激励Grms值相同的情况下,不同激励谱形会引起包装内部产品与包装间的侧向动压力变化,且与激励谱在包装系统共振频段内的Grms值大小有关,这进一步导致标签磨损量的差异。该研究成果为基于物流运输的瓶形包装品表面标签油墨振动磨损评价及测试方法的建立提供思路。

基于MapGIS的Label点法农业地质样点布置方法

以海南省东部某典型地区市县级农业地质普查为例,介绍了基于Map GIS的Lable点法样点布置方法。该方法首先将海南省第二次土地利用调查的26个土地利用小类归并成水田、旱地、果园、其他园地、林地、建设用地、滩涂、交通用地、水面、其他土地共10大类,图斑总数由9 932个归并为4 257个;然后将归并后的图斑按照面积大小划分为代表性依次降低的A、B、C三个级别;样点布置过程中,A级图斑采用传统500 m×500 m网格化方法布置样点,B级图斑采用基于Map GIS的Lable点法布置样点,C级图斑不布置样点。软件自动布置样点后,经必要的人工调整,在174 km^2的工作区共布置1 610个采样点,样点密度达9.25个/km^2,符合农业地质调查相关规范要求。方法有效性验证显示:与传统单一的333 m×333 m网格化样点布置方法相比,该方法布置的样点在可采性、代表性、准确性、合理性四方面都有显著优势,值得推广应用。

Influence of ear tags on the results of body composition analysis in mice

Background:The aim of this study was to investigate the influence of marking meth-ods on the outcomes of body composition analysis and provide guidance for the se-lection of marking methods in mouse body composition analysis.Methods:Male C57BL/6J mice aged 6 weeks were randomly assigned for pre-and post-ear tagging measurements.The body composition of the mice was measured using a small animal body composition analyzer,which provided measurements of the mass of fat,lean,and free fluid.Then,the mass of fat,lean and free fluid to body weight ratio was gained.Further data analysis was conducted to obtain the range and coeffi-cient of variation in body composition measurements for each mouse.The distribution of fat and lean tissue in the mice was also analyzed by comparing the fat-to-lean ratio.Results:(1)The mass of all body composition components in the ear tagging group was significantly lower than that in the control group.(2)There was a significant in-crease in the range and coefficient of variation of body composition measurements between the ear tagging group and the control group.(3)The fat-to-lean ratio in the ear tagging group was significantly lower than that in the control group.Conclusions:Ear tagging significantly lowered the results of body composition analy-sis in mice and higher the results of measurement error.Therefore,ear tagging should be avoided as much as possible when conducting body composition analysis experi-ments in mice.

酶介导的邻近细胞标记方法探究细胞间相互作用

细胞-细胞相互作用(cell-cell interactions,CCIs)可以通过细胞表面蛋白质、聚糖、脂质等介导的细胞间突触形成而发生,以维持机体稳态和调控生理功能。这些CCIs是复杂的,涉及许多不同的细胞表面和细胞内分子的参与。随着基础研究和转化医学的不断发展,如何准确识别细胞间相互作用并对其进行表征和定量,引起了广泛关注。近年来,研究CCIs的技术手段不断推陈出新,而邻近标记是一种十分有前景的研究细胞间相互作用的化学生物学方法。目前,主要有两种类型的标记策略。一种是依赖基因工程操作,在“诱饵”细胞表面表达外源酶,通过其与相邻细胞上的受体底物的直接结合,以便发生细胞间邻近标记。另一种是使用酶或小分子催化剂(例如光催化剂),通过基因工程重组表达或借助化学(化学酶)方法将它们偶联在“诱饵”细胞表面,在适当的刺激或激活后,靶向递送感兴趣的标记分子,实现邻近标记。其中,酶介导的邻近细胞标记方法在检测和表征CCIs上具有重要的应用价值。该综述将标记过程中涉及有酶参与的方法定义为酶介导的邻近细胞标记方法,这种方法的一个明显优势是,由于酶和受体底物之间直接的物理接触或酶催化产生高反应活性标记分子而实现小的标记半径范围。该综述旨在归纳与总结近年来开发的酶介导的邻近细胞标记方法的原理、优缺点及现有应用。

TSFC四步培训+GLO GERM标记评价模式应用效果研究

目的:探讨三级医院开展TSFC四步培训结合GLO GERM标记评价新模式在医院感染控制的应用效果。方法:2023年2月1日-8月31日医院开展感控知识技能培训考核,实验组的病房医护和勤工参加TSFC四步培训,对照组的病房医护和勤工参加常规培训,联合GLO GERM标记法考核各项操作。结果:穿脱防护用品考核结果对比,实验组总分和9项指标分数高于对照组,结合GLO GERM标记实验组暴露点数和暴露率低于对照组,差异具有显著统计学意义(P<0.005)。床单元消毒清洁考核,实验组勤工总分和5项指标分数高于对照组,结合GLO GERM标记实验组清除点数和清除率高于对照组,差异具有显著统计学意义(P<0.005)。不同性别、年龄段、职业、职称人员培训效果均有显著性差异。结论:TSFC四步培训结合GLO GERM标记评价模式在医院感染控制工作中更具有针对性和实用性,应用效果显著。

氘标记西布特罗合成方法研究与结构表征

同位素稀释质谱法为快速准确地检测动物源食品中β_(2)-受体激动剂西布特罗的含量提供了可能,也对稳定同位素标记西布特罗内标物的合成提出了需求。本文报道了一种氘标记西布特罗的新型合成方法,以2-硝基-5-溴苯甲腈为起始原料,经偶联、环氧化、取代、还原四步常规化学反应制备西布特罗-D_(9),具有路线短、操作简便、收率高等优点。该产物经核磁共振氢谱(^(1)HNMR)和质谱(HRMS)表征确认,化学纯度和同位素丰度均高于99.0%,可作为质谱检测内标使用。该方法也可用于其他苯乙醇胺类β_(2)-受体激动剂的合成。

体外法研究三肽-1铜的经皮吸收

研究通过拉曼光谱法和经皮吸收荧光标记法,探究三肽-1铜从表皮层到真皮浅层的经皮吸收规律。实验结果显示,通过拉曼光谱法的检测,与空白皮肤相比较,三肽-1铜在1560~1600 cm^(-1)为特征信号峰,三肽-1铜在皮肤作用4 h后,在皮肤0~100μm处均有经皮吸收,经皮吸收相对总量1.0403 a.u.。通过经皮吸收荧光标记法的检测结果表明,三肽-1铜在皮肤上分别作用1,4,24 h后,相对荧光强度分别为2.84×10^(6)、3.99×10^(6)、8.87×10^(6),随着作用时间的增加,相对经皮吸收量与经皮吸收深度均在逐渐增加,并且确定了三肽-1铜能够达到真皮层。该研究表明,三肽-1铜可以经由角质层和毛孔进入活性表皮层直至真皮浅层,从而具备发挥功效的基础,明确了三肽-1铜的经皮吸收方式,以及在更深层皮肤的经皮吸收规律,为其功效研究和配方应用提供了参考。

酶联免疫法和金标法对HIV抗体的检测结果比较

目的 探讨酶联免疫法和金标法对HIV抗体的检测结果,明确针对艾滋病更为有效的临床筛查手段。方法选取264例疑似艾滋病患者,采集入组患者静脉血并进行酶联免疫法与金标法检测HIV抗体。以临床诊断结果为准,比较酶联免疫法和金标法与临床检查结果的一致性;比较酶联免疫法和金标法对艾滋病的诊断效能。结果 264例疑似艾滋病患者中,经临床筛查试验和确证试验确诊225例。κ检验分析结果显示,酶联免疫法检查结果与临床诊断结果具有高度一致性(κ=0.897, P <0.05);金标法检查结果与临床诊断结果具有高度一致性(κ=0.902, P <0.05)。酶联免疫法与金标法诊断艾滋病的灵敏度、特异性与准确率比较,差异均无统计学意义(P>0.05)。结论 酶联免疫法和金标法对HIV抗体均具有较好的检出效果,可为艾滋病临床诊断提供较为准确的数据参考,临床检测中可根据患者自身情况选择相应的检测方法,必要时还可进行联合检测。

基于SRKDA的系统故障演化过程分解方法研究

为研究系统故障演化过程中可能蕴含的多种演化特征,对演化过程的分解进行研究,提出基于谱回归核判别分析(SRKDA)的演化过程分解方法。首先介绍演化过程的特点和分解原理,其次论证对象集合对演化过程的可表示性,给出分解方法流程,最后进行实例分析。研究结果表明:分解演化过程本质上是对象与系统功能状态对应关系的确定,各对象集合都对应了各自的子演化过程;线性和非线性条件下对象可表示各种功能状态;对象标签矩阵须满足标签值的均匀分布特征;使用SRKDA算法可以确定最大准确度和最优对象标签集合,实现演化过程的分解;实例分析得到在20000次迭代后最大准确度为0.85,3个子演化过程分别包含41,33,26个对象。研究结果可为系统故障过程的特征分析提供参考方法。

液相色谱-质谱/质谱法测定植物源性产品中强极性杀菌剂三乙膦酸铝残留

采用液相色谱-质谱/质谱法结合同位素内标法测定番茄、甘蓝、葡萄、金针菇、大米、花生等植物源性产品中强极性农药三乙膦酸铝。通过对色谱、质谱条件和前处理优化,确定了最佳的实验条件。样品用乙腈进行提取,经HLB固相萃取小柱净化,采用AQ C18柱色谱柱分离,以甲醇和0.15%甲酸溶液为流动相进行梯度洗脱,流速为0.1~0.2 mL/min。质谱采用多反应监测负离子扫描模式,同位素内标标准曲线法定量。三乙膦酸铝在20.0~800.0 ng/mL范围内线性良好,决定系数为0.9904。三乙膦酸铝定量限为100.0μg/kg。对6种植物源性产品进行3个水平加标回收试验,平均回收率范围为69.6%~112.3%,相对标准偏差为1.0%~9.8%。该方法前处理简便,灵敏度高,能满足国内外标准法规对植物源性产品中三乙膦酸铝残留限量的要求。