DCE-MRI参数联合IFIT1基因对腰椎间盘突出患者椎间盘退变程度的评估价值

探讨DCE-MRI参数及IFIT1基因对腰椎间盘突出症(LDH)患者椎间盘退变(IDD)程度的评估价值。随机选取确诊的66例LDH患者作为研究对象,根据改良Pfirrmann分级法将患者分为2组:轻中度IDD(Ⅰ~Ⅲ级)组(46例)和重度IDD(Ⅳ~Ⅴ级)组20例。通过DCE-MRI检查考察患者的K-trans值,采用日本骨科学会评分(JOA)评估腰椎功能,采用视觉模拟评分法(VAS)评估腰部疼痛,采用RT-PCR检测外周血单个核细胞(PBMC)中IFIT1的mRNA表达。轻中度IDD组的K-trans值显著低于重度IDD组。轻中度IDD组患者PBMC中的IFIT1 mRNA相对表达量显著低于重度IDD组。K-trans值与PBMC中的IFIT1 mRNA水平和VAS评分正相关,与JOA评分负相关(P<0.05)。PBMC中的IFIT1 mRNA水平与VAS评分正相关,与JOA评分负相关(P<0.05)。K-trans值和PBMC中的IFIT1 mRNA水平联合诊断重度IDD的AUC值、敏感性和特异性分别为0.991、91.3%和100.0%,AUC值和特异性均高于单独诊断。DCE-MRI检查中的K-trans值联合PBMC中的IFIT1 mRNA水平可用于LDH患者IDD程度的诊断。     

Kinetics and Mechanism of Catalytic Reduction of U(VI) with Hydrazine on Platinum Catalysts in Nitric Acid Media

The kinetics of U(IV) produced by hydrazine reduction of U(VI) with platinum as a catalyst in nitric acid media was studied to reveal the reaction mechanism and optimize the reaction process. Electron spin resonance (ESR) was used to determine the influence of nitric acid oxidation. The effects of nitric acid, hydrazine, U(VI) concentration, catalyst dosage and temperature on the reaction rate were also studied. In addition, the simulation of the reaction process was performed using density functional theory. The results show that the influence of oxidation on the main reaction is limited when the concentration of nitric acid is below 0.5 mol/L. The reaction kinetics equation below the concentration of 0.5 mol/L is found as: -dc(UO₂²⁺)/dt)=kc^0.5323(UO₂²⁺)c^0.2074(N₂H₅⁺)c^-0.2009(H⁺). When the temperature is 50 ℃, and the solid/liquid ratio r is 0.0667 g/mL, the reaction kinetics constant is k=0.00199 (mol/L)^0.4712/min. Between 20 ℃ and 80 ℃, the reaction rate gradually increases with the increase of temperature, and changes from chemically controlled to diffusion-controlled. The simulations of density functional theory give further insight into the influence of various factors on the reaction process, with which the reaction mechanisms are determined according to the reaction kinetics and the simulation results.     

A Au nanoparticle and polydopamine co-modified biosensor: A strategy for in situ and label-free surface plasmon resonance immunoassays

This article reports a surface plasmon resonance (SPR) strategy capable of label-free yet amplified in situ immunoassays for sensitive and specific detection of human IgG (hIgG), a serum marker that is important for the diagnosis of certain diseases. Primarily, a wavelength-modulated Kretschman configuration SPR analyzer was constructed, and Au film SPR biosensor chips were fabricated. Specifically, based on Au nanoparticles (AuNPs) adsorbed on the surface of the Au film, the AuNP/Au film was coated with polydopamine (PDA) to fix streptavidin (SA), and then the biotinylated antibodies were connected to the surface of the biosensor chip. The SPR analyzer was utilized for in situ real-time monitoring of hIgG. Due to the immunological recognition between the receptor and target, the surface plasmon waves produced by the attenuated total reflection were affected by the changes in the surface of the biosensor chip. The resonance wavelength (λ_R) of the output spectra gradually redshifted, and the redshift degrees were directly related to the target concentration. The biosensor can realize the in situ detection of hIgG, displaying satisfactory sensitivity, excellent specificity and stability. Briefly, by monitoring the shift in λ_R after specific binding, a new SPR immunoassay can be customized for label-free, in situ and amplified hIgG detection. The operating principle of this research could be extended as a common protocol for many other targets of interest.     

Plasmonic photoelectrochemical reactions on noble metal electrodes of nanostructures

Plasmonic noble metal nanostructures have been targeted due to their strong surface plasmon resonance at photoelectrochemical interfaces. Recently, it has been concluded that, the plasmonic noble metal nanostructures on photoexcitation permit the transfer of effective hot carriers (hot electron/hole pair) to nearby adsorbed molecules where, the transformed hot carriers can efficiently decrease the activation barrier of a reaction. In this review, our recent achievements in the plasmon-mediated chemical reactions of organic molecules such as para-aminothiophenol, substituted para-aminothiophenol and para-nitrothiophenol at nanostructures modified noble metal electrodes using surface enhanced Raman spectroscopy, electrochemical methods, and theoretical calculations will be discussed.     

一锅法可控合成金属有机框架材料Mn-荧光素用于核磁共振/荧光成像

通过一锅法,首次将核磁共振成像试剂Mn²⁺和荧光成像试剂荧光素（FSD）自组装于一个简单的金属有机框架材料（Mn-FSD）上。实验结果表明,Mn-FSD的粒径可被控制在微纳米水平内并进行生物成像。体外和体内实验结果证实,Mn-FSD可在细胞和裸鼠中显示强绿色荧光。同时,Mn-FSD表现出较高的弛豫值（r₁=4.95 L·mmol^-1·s^-1）。     

Expanding the Ligand Classes Used for Mn(II) Complexation: Oxa-aza Macrocycles Make the Difference

We report two macrocyclic ligands based on a 1,7-diaza-12-crown-4 platform functionalized with acetate (tO2DO2A²⁻) or piperidineacetamide (tO2DO2AM^Pip) pendant arms and a detailed characterization of the corresponding Mn(II) complexes. The X−ray structure of [Mn(tO2DO2A)(H₂O)]·2H₂O shows that the metal ion is coordinated by six donor atoms of the macrocyclic ligand and one water molecule, to result in seven-coordination. The Cu(II) analogue presents a distorted octahedral coordination environment. The protonation constants of the ligands and the stability constants of the complexes formed with Mn(II) and other biologically relevant metal ions (Mg(II), Ca(II), Cu(II) and Zn(II)) were determined using potentiometric titrations (I = 0.15 M NaCl, T = 25 °C). The conditional stabilities of Mn(II) complexes at pH 7.4 are comparable to those reported for the cyclen-based tDO2A²⁻ ligand. The dissociation of the Mn(II) chelates were investigated by evaluating the rate constants of metal exchange reactions with Cu(II) under acidic conditions (I = 0.15 M NaCl, T = 25 °C). Dissociation of the [Mn(tO2DO2A)(H₂O)] complex occurs through both proton− and metal−assisted pathways, while the [Mn(tO2DO2AM^Pip)(H₂O)] analogue dissociates through spontaneous and proton-assisted mechanisms. The Mn(II) complex of tO2DO2A²⁻ is remarkably inert with respect to its dissociation, while the amide analogue is significantly more labile. The presence of a water molecule coordinated to Mn(II) imparts relatively high relaxivities to the complexes. The parameters determining this key property were investigated using ¹⁷O NMR (Nuclear Magnetic Resonance) transverse relaxation rates and ¹H nuclear magnetic relaxation dispersion (NMRD) profiles.     

Ag@AgI/Ni薄膜的制备及其模拟太阳光催化性能

采用电化学方法制备Ag@AgI/Ni表面等离子体薄膜催化剂,使用扫描电镜(SEM),X射线衍射(XRD)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶体结构、光谱特性以及能带结构进行分析表征,在模拟太阳光照射下,把罗丹明B作为模拟污染物对薄膜的光催化活性与稳定性进行评价,采用向反应体系中加入活性物种捕获剂的方法对薄膜光催化机理进行探究。结果表明:最佳工艺下制备的Ag@AgI/Ni薄膜表面是由附着少量Ag粒子的AgI纳米晶构成。薄膜具有显著的表面等离子共振作用、优异的光催化活性和突出的光催化稳定性。光催化反应60 min,薄膜对罗丹明B的降解率(81.1%)是AgI/Ni薄膜的1.35倍,是TiO_2(P25)/ITO薄膜的1.61倍。在薄膜光催化活性基本保持不变的前提下可循环使用5次。薄膜表面纳米Ag的等离子共振对光阴极反应的活化是光催化性能提高的重要原因。提出了薄膜光催化降解罗丹明B的反应机理。     

Naphthalimide-rhodamine based fluorescent probe for ratiometric sensing of cellular pH

The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe(hereafter referred to as RBN) with a pK_a of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer(FRET), which can respond to different pH precisely through ratiometric fluorescence intensity(Ⅰ_(577)/Ⅰ_(540)). RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.     

LF-NMR结合化学模式识别鉴别油脂种类及餐饮废弃油脂

应用主成分分析(Principal component analysis,PCA)和聚类分析法(Cluster analysis,CA)对9种(27个)常见食用植物油及100个餐饮废油的低场核磁共振(Low-field nuclear magnetic resonance,LF-NMR)(T2)弛豫特性数据进行分析。结果表明:在正常食用油种类区分方面,主成分分析的效果较优,9种食用油在主成分分布图上按种类正确分组,边界清晰。而在正常食用油与餐饮废油的区分方面,聚类分析效果较优,引入30个待测样本后,聚类分析(127个样品,欧式距离=5)的正确率为94.49%,分析误判率为5.51%,分组效果良好。LF-NMR结合化学模式识别可实现对油脂种类及餐饮废弃油脂的鉴别。     

渤海稠油及其组分中杂原子化合物的负离子电喷雾-高分辨质谱分析

采用沉淀法和色谱分离法将渤海某油田稠油分离成沥青质、胶质、剩余分3个组分。采用负离子电喷雾技术(ESI)结合高分辨傅立叶变换离子回旋共振质谱仪(FT-ICR MS)研究了该稠油及各组分的分子组成。结果表明,剩余分中有较少的极性杂原子化合物能被负离子ESI电离,如N_1,N_1O_1,O_1和O_2类,其等效双键数(DBE)较小。胶质和原油中极性化合物有相同的杂原子类型,包括N_1,N_1O_1,N_1O_2,N_2,N_2O_2S_1,O_1,O_2,其中胶质和原油中N_1,O_1,O_2类化合物的DBE-碳数分布图相似。沥青质中富集高缩合度且多杂原子的酸性化合物,如含杂原子N_,S的氧化程度高的化合物(N_2O_1,N_1O_3,S_1O_3)及O_3类化合物,这些物质具有较高的界面活性,易吸附在界面上促进界面张力降低和增强界面膜强度,从而有利于乳状液稳定存在。N_1O_1,N_1O_2,N_1O_3类化合物,N_2O_1类化合物可能分别是N_1化合物,N_2化合物的氧化降解产物;随着氧化降解程度增加,降解产物的极性明显增强。