油品标记简介与国内政策分析

本文对油品标记进行了介绍,包括油品标记物特点、标记方法与油品标记的功能。此外,本文着重分析了油品标记的意义,油品标记既可以实现油品的分类与精细化管理,又可以有效实现油品监管。最后,本文依据国内政策形势分析了推动实施油品标记各集团利益博弈情况。     

激光标记塑料研究进展

阐述了3种激光标记方法（浅色基体标记深色、深色基体标记浅色、标记彩色）的标记原理及不同激光标记组合物的制备方法。总结了有机和无机类激光标记添加剂的发展现状,展望了激光标记方法的发展前景。     

基于核极限学习机的快速主动学习方法及其软测量应用

为提高主动学习方法的运行效率和降低人工标记成本,提出一种基于核极限学习机的快速主动学习方法,并将其应用于软测量建模中。首先,采用核极限学习机对无标记样本进行信息评估,将无标记样本的置信度作为样本选择评价准则,选择对改善模型性能最有价值的无标记样本进行标记;其次,充分考虑每次迭代过程的运算信息,引入矩阵反演公式优化样本选择策略,提升迭代过程样本评估的运行效率;最后,应用矩阵相似度理论对迭代过程的已标记样本数据进行信息度量,并将其作为迭代终止依据,以最小的标记代价提升模型性能。将所提方法应用于硫回收过程H₂S和SO₂浓度软测量研究中,仿真结果表明:所提方法不仅标记代价小,而且提高了迭代的快速性,比较全面地提升了主动学习算法的性能。通过开展本研究工作,为少标记样本情况下的软测量技术应用提供了一种新方法。     

管道智能内检测地面标记系统研究

地面标记系统是管道智能内检测的主要设备,可以为管道缺陷的准确定位提供参考点,提高缺陷点的定位精度.传统的标记系统是通过电缆通信方式逐一对标记器进行时间标定,工作量较大,因而,提出一种基于无线通信的技术,新型的标记系统可实现同时对多个标记器进行时间标定,极大地提高了工作效率.     

黑色玻纤增强尼龙6激光标记工艺及配方设计

在建立塑料激光标记模型的基础上,以黑色玻纤增强的尼龙6为研究对象,阐明了打标工艺参数、激光标记效果、标记区域微观结构三者的内在关联。发现合适的电流、频率、扫描速率能够引发尼龙6表面均匀起泡,获得亮度较高的标记效果;能量过高,气泡破裂甚至碳化,发黄严重;能量过低,不能诱导产生气泡,无法获得较好标记效果。进而从配方设计的角度出发,分别考察了激光标记助剂433、炭黑UVU对黑色玻纤增强尼龙6浅色标记效果的影响。结果显示,炭黑含量过低,则很难通过调节打标工艺参数获得高质量的标记效果;激光标记助剂的引入,虽然有助于材料吸收能量,但是限制了浅色标记效果亮度的上限。     

碳化硅量子点荧光标记串珠镰刀菌及其活体示踪

采用SiC量子点荧光标记与示踪技术,对串珠镰刀菌活体细胞进行荧光标记并实现了长时程荧光成像示踪,结果表明,碳化硅量子点标记的串珠镰刀菌活体细胞具有可调谐的荧光颜色,这是与其光学特性所决定的,即在不同激发光波长下呈现不同的荧光颜色;SiC量子点通过网格蛋白依赖的内吞方式进入活体细胞内部,实现了对串珠镰刀菌的稳定标记;同时这种标记由于量子点表面官能团与活体细胞的化学键耦合而显示出较强的抗漂白能力.     

稳定同位素标记氨基酸细胞培养联合质谱绝对定量技术在5、7、55型腺病毒鉴定中的应用

利用稳定同位素标记肽段的质谱绝对定量(AQUA)技术，实现了对5、7和55型人腺病毒的准确鉴定。采用细胞培养条件下稳定同位素代谢标记(SILAC)技术培养细胞至大肠杆菌生长至对数生长期，1 mmol/L异丙基硫代-β-D-半乳糖苷(IPTG)低温诱导蛋白表达，提取并利用谷胱甘肽S转移酶(GST)纯化富集相应标记的腺病毒六邻体蛋白。通过胶消化分别消化三种不同标记策略(非标记、中度标记和重度标记)的纯化蛋白，消化肽段等量混合脱盐后经纳流液相色谱-串联质谱(Nano HPLC-MS/MS)进行定量蛋白分析。通过SILAC实现大肠杆菌的完整代谢标记，诱导表达腺病毒六邻体蛋白，通过AQUA技术实现对非标记、中度标记、重度标记六邻体蛋白标志性肽段鉴定。成功实现SILAC三种不同标记策略条件下大肠杆菌中5、7、55型人腺病毒六邻体蛋白的完整标记，为5、7、55型人腺病毒感染的快速分型检测提供了新的鉴定策略。     

BrdU标记家兔成纤维细胞的体外及体内实验观察

目的用5-溴脱氧尿嘧啶核苷(BrdU)标记家兔皮肤成纤维细胞,确定最佳标记方法,探讨其作为成纤维细胞示踪方法的可行性。方法取12～16周龄健康中国大耳白兔颈部皮肤,胶原酶消化,分离并培养成纤维细胞。取第3代细胞,加入终浓度分别为2.5、5、10和15μg/ml的BrdU共培养,MTT法检测细胞的生长情况。分别用2.5、5、10和15μg/ml的BrdU标记第3代细胞,标记6、12、24和48h后,采用免疫荧光法检测各组细胞的标记阳性率。以最佳剂量及时间标记家兔成纤维细胞,与壳聚糖-甘油磷酸钠水凝胶混合后,注入兔颈内动脉,1周后,免疫荧光法观察植入细胞。结果加入BrdU48h内,各浓度的BrdU对家兔成纤维细胞生长的影响均不明显。标记剂量及标记时间均可影响标记率,但标记时间的影响更大。5μg/ml剂量标记24h,标记率可达(94.50±2.08)%,再加大标记剂量或延长标记时间,标记率提高不明显。以该方法标记的家兔成纤维细胞注入家兔颈内动脉1周后,可在兔颈内动脉观察到大量标记细胞。结论BrdU对家兔成纤维细胞的最佳标记方法为5μg/ml标记24h,该方法对细胞影响小,标记率高,适用于成纤维细胞体内示踪。     

橡胶制品用标记胶

本工作主要是为在目前广泛应用于工业、农业、国防和其他方面的、具有很好的耐介质和耐高温性能的丁腈胶、氟橡胶制品上作标记而进行的。对标记的颜色、形状、大小、数量以及每个标记所表示的具体内容等提出了要求。还提供了这两种橡胶制品用标记胶料的配方、胺液的制造方法和作标记的方     

可激光标记的聚酰胺6研究

研究了激光助剂的种类、含量等对聚酰胺6(PA6)激光标记性能的影响。结果表明,在PA6中加入珠光颜料或激光助剂,PA6的激光标记性能得到提高;同时,加入一定量的丙烯酸酯粉末橡胶提高了PA6的激光标记性能。     

质谱分析导向的稳定同位素标记技术进展

介绍了近年来发展的一系列具有代表性的质谱分析导向的低残留稳定同位素标记技术:二甲氧基甲砜基嘧啶衍生化、低残留稳定同位素标记季铵化衍生化、新型胍剂化合物的衍生化等技术与方法。一些在常规电喷雾或基质辅助激光解吸电离条件下无法有效离子化的目标分子,在衍生化后产生新的正电荷中心或成为容易被电离物种而被质谱检测,从而提高了这类化合物的质谱学检测灵敏度。该类研究显著优势在于所开发的衍生化试剂本身不是离子型化合物,新产生的电荷中心或易于离子化的基团由衍生化反应引入。过量的衍生化试剂易于除去,不会对随后的质谱分析产生明显干扰。这一系列研究成果在代谢组学、食品安全分析、质谱成像以及单细胞分析等方面具有广泛的应用价值。     

Tuning a Protein‐Labeling Reaction to Achieve Highly Site Selective Lysine Conjugation

Activated esters are widely used to label proteins at lysine side chains and N termini. These reagents are useful for labeling virtually any protein, but robust reactivity toward primary amines generally precludes site‐selective modification. In a unique case, fluorophenyl esters are shown to preferentially label human kappa antibodies at a single lysine (Lys188) within the light‐chain constant domain. Neighboring residues His189 and Asp151 contribute to the accelerated rate of labeling at Lys188 relative to the ≈40 other lysine sites. Enriched Lys188 labeling can be enhanced from 50–70 % to >95 % by any of these approaches: lowering reaction temperature, applying flow chemistry, or mutagenesis of specific residues in the surrounding protein environment. Our results demonstrated that activated esters with fluoro‐substituted aromatic leaving groups, including a fluoronaphthyl ester, can be generally useful reagents for site‐selective lysine labeling of antibodies and other immunoglobulin‐type proteins.     

Labeling DNA for single-molecule experiments: methods of labeling internal specific sequences on double-stranded DNA

This review is a practical guide for experimentalists interested in specifically labeling internal sequences on double-stranded (ds) DNA molecules for single-molecule experiments. We describe six labeling approaches demonstrated in a single-molecule context and discuss the merits and drawbacks of each approach with particular attention to the amount of specialized training and reagents required. By evaluating each approach according to criteria relevant to single-molecule experiments, including labeling yield and compatibility with cofactors such as Mg(2+), we provide a simple reference for selecting a labeling method for given experimental constraints. Intended for non-specialists seeking accessible solutions to DNA labeling challenges, the approaches outlined emphasize simplicity, robustness, suitability for use by non-biologists, and utility in diverse single-molecule experiments.     

Site‐Specific Incorporation of Chemical Fluorescence on Live Enterovirus‐71 Virion by Using an Organometallic Palladium Reagent To Monitor Virus Entry

Imaging live virus to monitor the viral entry process is essential to understand virus–host interactions during pathogen infection. However, methods for efficient labeling of live viruses, in particular labeling non‐enveloped viruses and tracing virus entry processes, remain limited. Recently, labeling by using organometallic palladium reagents has provided a highly efficient and selective way to bioconjugate cysteines of virus proteins. Here, site‐specific bioorthogonal labeling mediated by an organometallic palladium reagent on the surface of live enterovirus‐71 (EV71) was used to visualize its entry into live cells. In contrast to currently used immunofluorescence and membrane‐anchored dyes, this site‐specific and quantitative labeling of live EV71 allows temporal imaging of its entry into host cell membranes on the timescale of seconds with little negative impact on its virulence. This method revealed details of EV71 virus entry and has broad applicability for monitoring virus entry that is difficult to assess by using conventional protein‐labeling approaches.     

Isoindoline-Based Nitroxides as Bioresistant Spin Labels for Protein Labeling through Cysteines and Alkyne-Bearing Noncanonical Amino Acids

Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling (SDSL) is a powerful tool in protein structural research. Nitroxides are highly suitable spin labeling reagents, but suffer from limited stability, particularly in the cellular environment. Herein we present the synthesis of a maleimide- and an azide-modified tetraethyl-shielded isoindoline-based nitroxide (M- and Az-TEIO) for labeling of cysteines or the noncanonical amino acid para-ethynyl-l -phenylalanine (pENF). We demonstrate the high stability of TEIO site-specifically attached to the protein thioredoxin (TRX) against reduction in prokaryotic and eukaryotic environments, and conduct double electron–electron resonance (DEER) measurements. We further generate a rotamer library for the new residue pENF-Az-TEIO that affords a distance distribution that is in agreement with the measured distribution.     

Expanding the Strain-Promoted 1,3-Dipolar Cycloaddition Arsenal for a More Selective Bioorthogonal Labeling in Living Cells

The advent of bioorthogonal chemistry, more importantly the strain-promoted 1,3-dipolar cycloaddition of cyclooctynes with azides to give stable triazoles, has opened new avenues for the study of biomolecules in their native environment. While much effort has been focused on improving the kinetics of these reactions, very little attention has been given to their bioselectivity. In this review, we will take you on our journey that led us to develop new cyclooctyne probes with enhanced physical attributes, including water solubility, cell-surface labeling selectivity and fluorogenic capabilities. We then went on to expand the bioorthogonal chemistry toolbox by focusing on the development of new chemical reporters. Here you will read about our work investigating the use of other 1,3-dipoles, including nitrile oxides and diazo reagents, for the labeling of biomolecules, and more recently highly biostable sydnones that can be exploited to selectively influence glycan-processing enzymes.     

Bacterially Derived Antibody Binders as Small Adapters for DNA-PAINT Microscopy

Current optical super-resolution implementations are capable of resolving features spaced just a few nanometers apart. However, translating this spatial resolution to cellular targets is limited by the large size of traditionally employed primary and secondary antibody reagents. Recent advancements in small and efficient protein binders for super-resolution microscopy, such as nanobodies or aptamers, provide an exciting avenue for the future; however, their widespread availability is still limited. To address this issue, here we report the combination of bacterial-derived binders commonly used in antibody purification with DNA-based point accumulation for imaging in nanoscale topography (DNA-PAINT) microscopy. The small sizes of these protein binders, relative to secondary antibodies, make them an attractive labeling alternative for emerging superresolution techniques. We present here a labeling protocol for DNA conjugation of bacterially derived proteins A and G for DNA-PAINT, having assayed their intracellular performance by targeting primary antibodies against tubulin, TOM20, and the epidermal growth factor receptor (EGFR) and quantified the increases in obtainable resolution.     

新型吖啶-二氧化硅荧光纳米颗粒的合成及表征

利用油包水的反相微乳液法,运用TritonX-100（曲拉通X-100）/正己醇/环己烷微乳液自组装体系,分别以吖啶、9-氨基吖啶、9-（2-氨基苯胺基）吖啶为核包覆SiO2,制备得到核壳型荧光氧化硅纳米颗粒。该方法克服了传统方法荧光试剂泄露的问题。透射电子显微镜检测和荧光光谱分析表明,所制得的纳米颗粒荧光强度高,荧光性质稳定,具有潜在生物亲和性,可望作为新型的荧光标记物。     

Platinum(II)‐Catalyzed Allylation of CO and CN Bonds under Hydrogenation Conditions

The nucleophilic addition of allylplatinum to a range of electrophiles including carbonyls, oximes, and hydrazones was examined. Platinum(II) catalysts and allene substrates were subject to hydrogenation conditions to generate nucleophilic allylplatinum complexes without using a stoichiometric amount of toxic and sensitive organometallic reagents. The allylplatinum intermediates reacted with CO and CN bonds to produce the corresponding homoallylic alcohol and amine derivatives in good yield. The Pt‐catalyzed allylation of CN bonds is the first example performed under hydrogenation conditions. A reaction mechanism initiated with the hydrometalation of allenes by Pt H species is proposed based on deuterium labeling studies.     

A flexible method for the conjugation of aminooxy ligands to preformed complexes of nucleic acids and lipids

Attachment of targeted ligands to nonviral DNA or RNA delivery systems is a promising strategy that seeks to overcome the poor target selectivity generally observed in systemic delivery applications. Several methods have been developed for the conjugation of ligands to lipids or polymers, however, direct conjugation of ligands onto lipid- or polymer-nucleic acid complexes is not as straightforward. Here, we examine an oximation approach to directly label a lipoplex formulation. Specifically, we report the synthesis of a cationic diketo lipid DMDK, and its use as a convenient ligation tool for attachment of aminooxy-functionalized reagents after its complexation with DNA. We demonstrate the feasibility of direct lipoplex labeling by attaching an aminooxy-functionalized fluorescent probe onto pre-formed plasmid DNA-DMDK lipoplexes (luciferase, GFP). The results reveal that DMDK protects DNA from degradation on exposure to either DNase or human cerebral spinal fluid, and that simple mixing of DMDK lipoplexes with the aminooxy probe labels the complexes without sacrificing transfection efficiency. The biocompatibility and selectivity of this method, as well as the ease of bioconjugation, make this labeling approach ideal for biological applications.