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.     

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.     

水相中磷钼酸催化三组分合成烯丙基胺

以磷钼酸作为催化剂，芳香醛、胺和三丁基烯丙基锡三组分在水作为溶剂，室温下高产率的得到相应的烯丙基胺。     

钯-碳/NaHCO3催化下2,4-二氯嘧啶的区域选择性脱氯反应：一种合成2-氯嘧啶的有效方法

本文报道了一种合成2-氯嘧啶的有效方法。易得原料2,4-二氯嘧啶在钯-碳/NaHCO3作用下可以区域选择性地脱除2位氯原子得到2-氯嘧啶。2-氯嘧啶可以用作多种复杂嘧啶衍生物的有效合成砌块。     

Effect of Water Vapor Absorption on Measurements of Atmospheric Nitrate Radical by LP-DOAS

利用长程差分吸收光谱技术进行大气NO3自由基测量时，水汽的强烈吸收叠加在测量光谱中，对NO3的精确反演和探测限带来较大的影响. 通过分析水汽吸收的非线性效应，建立了一种去除水汽影响的有效方法. 通过测量日间大气吸收谱，并考虑日间水汽与夜晚水汽变化量，一同参与数据拟合，结果表明该方法可以有效地去除水汽吸收的影响. 把该方法应用于在珠三角外场实验中，获得了好的效果，探测限达到3.6 ppt。