一种检测CO32-比率荧光探针的合成及其在细胞成像中的应用

本文设计开发了一种以2,6-二甲酰基对甲苯酚为母体的新型荧光探针HMI,可用于高效识别EtOH-H₂O (8/2, v/v, HEPES 10 mM, pH =7.4)体系中的CO_3^2-。HMI在660 nm处显示发射带,加入CO_3^2-后,在600 nm的等吸收点激发时,原来在660 nm处的荧光淬灭,而以540 nm为中心的新发射带荧光显着增加,为比率型荧光探针。HMI对CO_3^2-表现出高选择性且具有较强的抗干扰能力。此外,荧光探针HMI对CO_3^2-荧光响应的检测限较低,可达到3.938×10^_-6 M。更具有意义的是,HMI探针对CO_3^2-的检测能够在实际水样中起到很好的应用,而且细胞成像研究表明,HMI可用于活体MCF-7细胞中CO_3^2-的成像。     

Cytotoxic and NF-κB inhibitory sesquiterpene lactones from Piptocoma rufescens

Six new (1-6) and eight known germacranolide-type sesquiterpene lactones, along with several known phenylpropanol coumarates and methylated flavonoids, were isolated from the leaves of Piptocoma rufescens, collected in the Dominican Republic. The new compounds were identified by analysis of their spectroscopic data, with the molecular structure of 3 being established by single-crystal X-ray diffraction. The absolute configurations of the sesquiterpene lactones isolated were determined from their CD and NOESY NMR spectra, together with the analysis of Mosher ester reactions. Bioassay screening results showed the majority of the sesquiterpene lactones isolated (1-13) to be highly cytotoxic toward the HT-29 human colon cancer cell line, with the most potent compound being 15-deoxygoyazensolide (10, IC(50), 0.26 μM). In addition, several of the sesquiterpene lactones exhibited NF-κB (p65) inhibitory activity.     

Fe_3O_4 nano-whiskers by ultrasonic-aided reduction in concentrated NaOH solution

Fe 3 O 4 nano-whiskers were synthesized via ultrasonic-aided reduction of FeCl 2 ·4H 2 O with N 2 H 4 ·H 2 O in concentrated NaOH solution. Phase identification and morphology observation were conducted by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM). Face scanning energy dispersive spectrum (face scanning EDS) and two-dimensional fast Fourier transform (2DFFT) for element distribution were carried out for confirming compos...     

Effects of oxidation pretreatment temperature on Kovar used as CO_2 reforming catalyst

The effect of oxidation pretreatment temperature(500 ~ 1 000 ℃) on the catalytic activity of Kovar applied on hydrocarbon CO2reforming was examined. Catalytic performance evaluation using tetradecane at 800 ℃ with 70 μmol/s CO2revealed 700 and 1 000 ℃ as the best pre-oxidation temperature in producing CO and H2,respectively. XRD and SEM-EDX analyses showed that a separate metal oxide layer composed of iron oxide(Fe2O3and F3O4),nickel,cobalt,and possibly their respective oxides started to form when oxidation was conducted at 700 ℃ or higher.The presence of iron enhanced the stability of nickel in the structure while the compact structure of Fe3O4resulted into the formation of a thick and rigid metal oxide layer on the surface of the Kovar tube. The strong physical bond between the metal oxide layer and Kovar tube provided the catalyst good mechanical strength and consequently good catalytic activity.     

NCIPLOT: a program for plotting non-covalent interaction regions

Non-covalent interactions hold the key to understanding many chemical, biological, and technological problems. Describing these non-covalent interactions accurately, including their positions in real space, constitutes a first step in the process of decoupling the complex balance of forces that define non-covalent interactions. Because of the size of macromolecules, the most common approach has been to assign van der Waals interactions (vdW), steric clashes (SC), and hydrogen bonds (HBs) based on pairwise distances between atoms according to their van der Waals radii. We recently developed an alternative perspective, derived from the electronic density: the Non-Covalent Interactions (NCI) index [J. Am. Chem. Soc. 2010, 132, 6498]. This index has the dual advantages of being generally transferable to diverse chemical applications and being very fast to compute, since it can be calculated from promolecular densities. Thus, NCI analysis is applicable to large systems, including proteins and DNA, where analysis of non-covalent interactions is of great potential value. Here, we describe the NCI computational algorithms and their implementation for the analysis and visualization of weak interactions, using both self-consistent fully quantum-mechanical, as well as promolecular, densities. A wide range of options for tuning the range of interactions to be plotted is also presented. To demonstrate the capabilities of our approach, several examples are given from organic, inorganic, solid state, and macromolecular chemistry, including cases where NCI analysis gives insight into unconventional chemical bonding. The NCI code and its manual are available for download at http://www.chem.duke.edu/~yang/software.htm.     

基于2-苯基-4-喹啉酸及双咪唑类配体的钴(Ⅱ)配合物的合成、表征、磁性和电化学性质

利用2-苯基-4-喹啉酸、苯-1,4-双(咪唑基-1-甲基)和乙酸钴在二甲基甲酰胺和水的混合溶剂中反应,得到配合物[Co(pqba)2(biyb)](1)(Hpqba=2-苯基-4-喹啉酸,biyb=苯-1,4-双(咪唑基-1-甲基))。采用元素分析、红外光谱、X单晶衍射结构分析、热重分析等方法对配合物进行了表征和结构测定。配合物1属单斜晶系,C2/c空间群。配合物1中的biyb配体采用双齿桥链模式连接金属钴离子首先形成一维"之"字链,通过π…π堆积作用,进一步拓展为二维超分子结构。循环伏安法测试结果说明配合物1的电解过程为准可逆过程。磁化率测量表明,配合物1具有反铁磁性质。     

基于2-苯基-4-喹啉酸及双咪唑类配体的钴(Ⅱ)配合物的合成、表征、磁性和电化学性质

利用2-苯基-4-喹啉酸、苯-1, 4-双(咪唑基-1-甲基)和乙酸钴在二甲基甲酰胺和水的混合溶剂中反应, 得到配合物[Co(pqba)₂(biyb)](1) (Hpqba=2-苯基-4-喹啉酸, biyb=苯-1, 4-双(咪唑基-1-甲基))。采用元素分析、红外光谱、X单晶衍射结构分析、热重分析等方法对配合物进行了表征和结构测定。配合物1属单斜晶系, C2/c空间群。配合物1中的Biyb配体采用双齿桥链模式连接金属钴离子首先形成一维“之”字链, 通过π…π堆积作用, 进一步拓展为二维超分子结构。循环伏安法测试结果说明配合物1的电解过程为准可逆过程。磁化率测量表明, 配合物1具有反铁磁性质。     

MOF-1和Tb@MOF-1荧光探针的设计、 合成及对痕量Cr2O72-、 S2O82-离子的识别

采用5-((4-吡啶基)甲氧基)-异烟酸(H₂PLIA)、1,3,5-三(1-咪唑基)-苯(TIB)合成了金属有机骨架[Cd(PLIA)(TIB)]_n (MOF-1),MOF-1是具有理想一维孔道的二维结构化合物,其一维孔道由柔性三角形PLIA^2-配体和刚性三角形TIB配体间隔形成。利用MOF-1 易掺杂的优势,采用后修饰合成策略制备了Tb@MOF-1。对MOF-1 和Tb@MOF-1 进行了基本表征及荧光探针性能研究。2种探针材料具有相同的结构。MOF-1和Tb@MOF-1分别对水溶液中的Cr₂O₇^2-和S₂O₈^2-离子具有较强荧光识别能力,均有响应时间快,稳定性、选择性、灵敏度高的特点。研究了MOF-1和Tb@MOF-1对Cr₂O₇^2-和S₂O₈^2-的荧光识别机理,其不同可能与Tb³⁺离子掺杂有关。     

Erratum to "Aerosol pollution in China: Present and future impact on environment"

PARTICUOLOGY regrets that the above paper was mistakenly classified as a ‘Review’ rather than an ‘Invited paper’ when originally published in volume 7, issue 6, 426–431.