羟基磷灰石负载放射性18F作为分子影像纳米探针在生物医学中的应用

采用简便有效的方法,制备了生物兼容性强、放射性标记羟基磷灰石(HAp)纳米粒子的正电子发射计算机断层显像(PET)纳米探针。在合成HAp纳米粒子的过程中,放射性的~(18)F作为掺杂剂,占据HAp晶格中羟基位置,在短时间内牢固地标记到HAp上。~(18)F不仅标记在纳米粒子的表面,而且还通过强的化学键标记在纳米颗粒的内部。以达到提高标记量并防止辐射泄漏的目的。设计的高标记量的放射性纳米探针应用于动物实验并靶向到达脏器器官。     

Li＋在PC＋DMF混合溶剂中优先溶剂化的13C NMR研究

利用¹³C NMR光谱技术研究了Li^＋在碳酸丙烯酯(PC)＋N,N-二甲基甲酰胺(DMF)混合溶剂中的优先溶剂化现象. 根据溶剂分子中碳原子的化学位移随锂盐浓度的变化关系, 确定了与Li^＋发生配位的原子. 碳原子的配位位移值随混合溶剂组成的变化关系表明, 在LiClO₄＋PC＋DMF混合物中, DMF分子对Li^＋的溶剂化作用较PC分子强. 定量计算得到, 在n(PC)∶n(DMF)＝1∶1(摩尔比)的混合溶剂中, PC与DMF分子数在Li^＋第一溶剂化层中的比率为0.12, 说明Li^＋优先被DMF分子溶剂化.     

Li＋在PC＋DMF混合溶剂中优先溶剂化的13C NMR研究

利用¹³C NMR光谱技术研究了Li^＋在碳酸丙烯酯(PC)＋N,N-二甲基甲酰胺(DMF)混合溶剂中的优先溶剂化现象. 根据溶剂分子中碳原子的化学位移随锂盐浓度的变化关系, 确定了与Li^＋发生配位的原子. 碳原子的配位位移值随混合溶剂组成的变化关系表明, 在LiClO₄＋PC＋DMF混合物中, DMF分子对Li^＋的溶剂化作用较PC分子强. 定量计算得到, 在n(PC)∶n(DMF)＝1∶1(摩尔比)的混合溶剂中, PC与DMF分子数在Li^＋第一溶剂化层中的比率为0.12, 说明Li^＋优先被DMF分子溶剂化.     

游离125I与血浆蛋白的结合及其对血药浓度测定的影响

通过体内、外实验, 研究了游离125I与血浆蛋白的结合及其在三氯乙酸(TCA)沉淀后的沉淀百分率, 并与125I-RGD-Sak在SD大鼠中不同时间血药浓度的结果进行了比较. 结果表明, 游离125I能与血浆蛋白结合, 并为TCA所沉淀, 且在一定范围内, 游离125I与血浆蛋白结合后的沉淀百分率与温育时间及游离125I的活度无关. 体内、外实验中, 游离125I与血浆蛋白结合后的沉淀百分率分别为(1.26±0.14)%及(1.38±0.33)%. 沉淀物中含有吸附在沉淀物表面的游离125I, 该吸附需要用TCA沉淀2~3次才能去除. 采用125I核素示踪法进行生物类制品的药代动力学研究时, 应对游离125I的影响进行校正.     

CP/MAS 13C-NMR技术对桉木浆纤维素微观结构的研究

利用交叉极化结合魔角旋转技术13C 核磁共振法(CP/MAS ¹³C NMR)对桉木浆纤维的微观结构进行研究, 为进一步研究木质纤维素材料开发过程中反应障碍特征奠定基础. 通过对NMR光谱C1区(δ 102～108)进行洛仑兹拟合, 得到桉木浆纤维中纤维素Iα的相对含量为26.92%, 纤维素Iβ的相对含量为52.04%, 主要以纤维素Iβ晶体形式为主. 通过计算纤维素C4结晶区(δ 86～92)和非结晶区(δ 80～86)的相对含量得到桉木浆的纤维素结晶度为47%. 通过洛仑兹和高斯函数的混合模型对NMR光谱C4区(δ 80～92)进行拟合得到基原纤尺寸和微原纤横向尺寸分别为4.0与17.9 nm, 并通过计算不同形态的结晶纤维素的相对含量得到纤维素结晶度为51%, 证实了在微原纤内部次晶纤维素的存在.     

AgCuO2：制备及其在碱性溶液中的电化学行为

长期以来,由于M nO2碱性电池具有放电容量较大,比能量较高,低温性能优良,性能可靠等优点,因此传统的碱性电池一直采用M nO2作为正极活性物质,然而其容量的进一步提高受到了M nO2电极的限制[1]。随着人们对化学电源需求的日益扩大和现有电极材料资源的日益萎缩,寻求放电容量大、     

整合素αvβ3 靶向PET探针 18 F-c(RGDfK) 在Cu(Ⅰ)催化体系中的点击合成

通过2-叠氮乙基对甲苯磺酸酯的18F-亲核取代反应, 制备了[18F]2-氟叠氮乙烷, 并与丙炔酸修饰的c(RGDfK)反应, 采用常用的CuSO4/NaVc催化体系, 并尝试了CuI(s)和CuI/NH4OH 2种催化体系, 通过点击化学方法合成了整合素αvβ3靶向PET探针[18F]氟乙基-1,4-取代1,2,3-三唑c(RGDfK)[18F-c(RGDfK)]. 在CuSO4/NaVc的催化下, 18F-c(RGDfK)的总合成时间约为60 min, 总收率62%(从[18F]F-起计, 经过衰变校正). 实验结果表明, 点击化学方法高效便捷, 适于多肽的18F标记.     

Evaluation of procedures for solid-phase extraction of [125I]-methodone from serum on to discs and cartridges

Summary Biological samples must be purified before chromatography to eliminate interfering compounds. Discs have recently been developed to enhance the performance of solid-phase extraction (SPE) and reduce solvent consumption. This type of support is available in all the bonded-phases typically found in conventional packed SPE devices. The process for solid-phase extraction of [¹²⁵I]-methadone from water and serum (i.e. retention and losses of [¹²⁵I]-methadone during sample loading, washing, elution, etc.) has been studied to determine the behaviour of this compound on several extracting supports. For serum solutions we observed significant matrix effects on discs because of their low capacity. This resulted in loss of [¹²⁵I]-methadone during the loading step because the contact time between the analyte and the functional groups of the support was too short. Although mixed-mode discs, which have both hydrophobic and cation-exchange extraction mechanisms, do not perform as well as conventional cartridges, they can, nevertheless, be used before liquid chromatographic analysis because of their several mechanical and economical advantages in comparison with cartridges.     

Halide ion effect on the chloroform chemical shift in supramolecular complexation studies with tetra-n-butylammonium salts: a 1H NMR and X-ray study

A ¹H NMR spectroscopic study of tetra-n-butylammonium halides (TBAX: X = Cl^? , Br^?  or I^? ) in CDCl₃ solutions was conducted. Complexation studies of TBAX salts with different host molecules using ¹H NMR in CDCl₃ have previously revealed that the reference residual CHCl₃ proton signal had been shifted downfield. The aim of the study was to quantify the extent of these chemical shift changes with TBAX salts. Linear concentration–chemical shift relationships in each case were obtained from the resulting titration plots obtained from the addition of the TBAX salts alone to CDCl₃. Interactions in the solid state as determined by X-ray crystallography support the solution-state investigations indicating halide ion–chloroform proton interactions.     

曝光强度对卤化银微晶中载流子行为及其陷阱效应的影响

针对卤化银感光材料潜影形成过程中光作用动力学问题,分析了曝光强度对光生载流子行为和电子陷阱效应的影响,认为伴随着曝光强度的增加,影响光电子衰减的因素由电子陷阱起主要作用演化到电子陷阱和复合中心共同起作用进而演化到复合中心起主要作用.     

Influence of chemical effect on the K-shell X-ray production cross-sections and radiative Auger ratios of Zn complexes

In this study, _σK_α${\sigma }_{{\text{K}}_{\mathrm{\alpha }}}$, _σK_β${\sigma }_{{\text{K}}_{\mathrm{\beta }}}$ production cross-sections, KLM/K_α and KMM/K_β radiative Auger intensity ratios of Zn in different complexes were measured. The samples were excited by 59.5 keV γ-rays from a ²⁴¹Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The charge transfer effects on central Zn atom was investigated by using the behaviors of different ligands in these complexes.     

Influence of the vacuum on the separation efficiency in coupled (GC)2-MS

Summary The van Deemter polts for the same glass capillary column one coupled to an FID detector and once to an MS instrument are compared. With full vacuum at the capillary end the column still produces 75% of the maximum attinable separation efficiency.     

Influence of silica fillers during the electron irradiations of DGEBA/TETA epoxy resins, part I: Study of the chemical modification on model compounds

The study of the chemical modifications of model compounds of the diglycidyl ether of bisphenol A/triethylene tetramine (DGEBA/TETA) epoxy resins under electron irradiation is described. The reaction of butylamine and N,N′-diethylethylene diamine with DGEBA afforded model compounds of the DGEBA/TETA structure. Nanometric silica was used as filler for these model compounds. ¹H and ¹³C NMR analyses allowed identification of the chemical structures before and after irradiation. C-O and C-N scissions were observed with the formation of phenolic and methyl-ketone ends and of primary and secondary amines. For the model compounds containing the 1,2-diaminoethylene structure, the scission of the C-N bond is followed by the formation of an enamine end. The mechanisms of the different bond scissions are proposed. The presence of the nanometric silica fillers allows the protection of some C-N bonds. The reaction of the chemical species formed by electron irradiation with the reactive functions at the silica surface is proposed to explain the chemical modifications observed on the irradiated filled model compounds.     

Influence of the crystallinity on the Li+ intercalation process in Nb2O5 films

Nb₂O₅ thin films were prepared by the Pechini method. The effect of the film crystallinity on the electrochemical and electrochromic properties was investigated. A relationship between the crystalline structure and the Li⁺ intercalation/extraction process, stability and kinetics was observed. A significant decrease in the electrochemical response was observed as a function of the number of cycles for films treated at 400 and 450 °C. However, as the calcination temperature increases this effect disappears. XRD studies shown that at 400 °C, the material is amorphous, evolving to orthorhombic phase. The transmittance variation as well as the coloration efficiency increases as the temperature is increased. In the initial cycles the intercalation charge is higher for the amorphous oxide than for the orthorhombic phase. However, the variation in the optical density is small. On the other hand, the charge of the orthorhombic phase oxide does not change. These results suggest that there are two different processes associated with Li⁺ intercalation, but only one of them leads to the coloration process.     

制备条件影响碳酸羟基磷灰石晶格的计算分析

在碳酸羟基磷灰石(CHA)结构分析中,对A型取代(CO₃^2-取代OH^-)和B型取代(CO₃^2-取代PO₄^3-)2种取代的稳定性仍存有争议。为了研究碳酸取代的可能位置和2种取代稳定性,本文利用计算机辅助手段详细研究了不同反应顺序和不同反应试剂对碳酸羟基磷灰石晶体结构的影响。本实验分别采用含Na和不含Na 2种不同的反应试剂,分别在HA生成过程中和HA生成以后加入CO₃^2-,通过离子共沉淀法制备了4种碳酸羟基磷灰石。通过X射线衍射(XRD)、红外光谱(IR)对他们的结构和基团进行了表征,并用Jade 6.5, Materials Studio 4.0以及Origin 7.0进行了精修、计算和拟合。结果表明,无论工艺过程如何变化,均主要生成晶体能量较低、晶格结构稳定的B型取代碳酸羟基磷灰石;与普通磷灰石相比,由于存在晶格畸变,因此碳酸取代磷灰石的结晶度下降;碳酸根在反应溶液中的浓度影响CHA的晶格畸变程度,较高游离碳酸浓度引起的晶格畸变大;Na⁺的引入,可以降低碳酸羟基磷灰石中的晶格畸变,从而提高结晶度;含Na的B型取代主要是取代Ca(Ⅱ)位置的Ca离子。IR分析结果表明四种碳酸羟基磷灰石中的CO₃^2-均以B型取代为主,通过对870 cm^-1附近峰的拟合,计算出材料中A型取代和B型取代的比值。     

Influence of several factors on potential-modulated DNA cleavage by the Cu(en)2 and Cu(EDTA) complexes

Potential-modulated DNA cleavage in the presence of copper–ethylenediamine (en) and –ethylenediamine tetraacetic acid (EDTA) complexes was investigated at a gold electrode in a thin layer cell. DNA can be efficiently cleaved through production of active oxygen species at −0.50 V (vs. Ag/AgCl/KCl(sat)) by reducing Cu(en)₂²⁺ to Cu(en)₂⁺ or Cu(EDTA)²⁻ to Cu(EDTA)³⁻. The extent of DNA cleavage increased as the working potential was shifted more negative and the electrolysis time was increased in air-saturated solution. When a small flow of O₂ was passed through the solution during electrolysis, the extent of DNA cleavage was dramatically enhanced. In the absence of Cu(en)₂²⁺ or Cu(EDTA)²⁻ complex, slight DNA cleavage was observed at a more negative working potential due to the reduction of oxygen at the electrode. This observation suggests that potential-modulated DNA cleavage was caused mainly by electrochemical reduction of the Cu(en)₂²⁺ or Cu(EDTA)²⁻ complex in the presence of oxygen. The cleaved DNA fragments were separated by high performance liquid chromatography (HPLC). The experimental results proved that this method of potential-modulated DNA cleavage by Cu(en)₂²⁺ and Cu(EDTA)²⁻ complexes is simple, mild and highly efficient.     

Influence of the central metal on the crystal structures and electronic structures of biferrocene trinuclear complexes

Five metal-bridged biferrocene complexes of the Schiff-base ligand (HL = S-benzyl-N-(ferrocenyl-1-methyl-methylidene)dithiocarbazate) have been studied by single crystal X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy. The crystal structures of the complexes show that the central metal ions are tetra-coordinated by two ligands in two modes: the central d⁸ transition metal ions (Ni²⁺, Pd²⁺, and Pt²⁺) are nearly square-planar coordinated and the d¹⁰ transition metal ions (Zn²⁺ and Cd²⁺) are tetrahedrally coordinated. Interestingly, the isomer shifts in ⁵⁷Fe Mössbauer spectroscopy are also of two kinds: d⁸ transition metal ions (0.097-0.247 mm/s) and d¹⁰ transition metal ions (0.416-0.435 mm/s).