A novel small-molecule near-infrared II fluorescence probe for orthotopic osteosarcoma imaging

Osteosarcoma is the most common primary malignant tumor of bone, particularly among children and adolescents. Advances in imaging, surgical techniques, and implants have dramatically reduced the need for amputation in the past three decades.Recently, in vivo fluorescence imaging in the second near-infrared window(NIR-II, 1,000–1,700 nm) shows impressive advantages of deeper tissue penetration and higher spatial resolution, which makes it a promising tool for the early diagnosis and post-operative observation of Osteosarcoma. To the best of our knowledge, this paper is the first time to develop a novel NIR-II fluorescence probe conjugated with an osteosarcoma targeted oligopeptide for molecular tumor imaging in a xenograft orthotopic osteosarcoma mouse model.     

Total synthesis and cytotoxicity studies of a cyclic depsipeptide with proposed structure of palau'amide

[structure: see text] Total synthesis of a cyclic depsipeptide with proposed structure of palau'amide is achieved, which features a stereoselective elaboration of its 5,7-dihydroxy-2,6-dimethyldodec-2-en-11-ynoic acid unit. The synthetic compound has potent cytotoxicity against three tumor cell lines but different rotation and NMR data compared to those reported for palau'amide, which implies that its conformation is close to that of palau'amide but that some stereochemistry in palau'amide was misassigned.     

Structural and photocatalytic properties of the new solid photocatalyst In2BiTaO7

In₂BiTaO₇ was synthesized using the solid-state reaction method and its photocatalytic properties were investigated. The results of powder X-ray diffraction (XRD) indicated that the compound crystallizes in the pyrochlore-type structure, cubic system with space group Fd-3m. The lattice parameter is 10.6972(1) ?. In addition, the compound shows strong optical absorption in the visible region (λ > 420 nm) and the band gap of In₂BiTaO₇ was estimated to be about 2.47 eV. For the photocatalytic reaction, H₂ or O₂ evolution was observed from CH₃OH/H₂O or AgNO₃ solution respectively with In₂BiTaO₇ as the photocatalyst under visible light irradiation, indicating that In₂BiTaO₇ is responsive to visible light for splitting water. Furthermore, the catalyst remained photoactive in the wavelength range up to 510 nm. Photocatalytic degradation of methylene blue (MB) dye over the compound was further investigated under visible light irradiation. The results showed that complete removal of aqueous MB could be achieved after irradiation for 135 min over In₂BiTaO₇. Furthermore, under visible light irradiation In₂BiTaO₇ showed markedly higher catalytic activity compared to P-25 for MB photocatalytic degradation.     

N—磷酰化二肽的分光光度法测定

利用双缩脲试剂，在可见光区建立了Ｎ－磷酰化二肽、二肽以及磷酰化多肽的分光光度定量分析方法。在经典的双缩脲分光光度法的实验条件下，观察到Ｎ－磷酰化二肽、二肽与双缩脲试剂的复合物的最大吸收波长均为６２０ｎｍ及Ｎ－磷酰基对二肽有很强的增色作用。     

Simultaneous determination of triterpene saponins in ginseng drugs by high-performance liquid chromatography

A HPLC method for the simultaneous determination of 11 triterpene saponins with four-type aglycones (protopanaxadiol, protopanaxatriol, ocotillol and oleanolic acid types) in Ginseng drugs was developed and validated. Using a gradient of acetonitrile and 10 mM K-phosphate buffer (pH 5.80) as the mobile phase and UV detection at 196 nm, more than 18 ginsenosides with different aglycones were separated satisfactorily within 60 min. The detection limits (signal/noise> or =3) were 0.1 microg for ginsenosides Rb1, Rc, Rd, Re and Rg1, chikusetsusaponin III, and notoginsenoside R2, 0.2 microg for gisenoside Ro and chikusetsusaponin IVa, 0.3 microg for chikusetsusaponin IV, and 3 microg for majonoside R2. The calibration curve of each saponin had a correlation coefficient close to 1. Intra- and interday precisions were less than 2.1% (n=5) and 3.3% (n=15), respectively. The recovery rates of extraction were in the range of 96.4-102.7% for all ginsenosides. By adopting this method, the determinations of 11 ginsenosides in three Ginseng drugs derived from Panax ginseng, Panax vietnamensis var. fuscidiscus and Panax japonicus (Japan) were achieved.     

Caged Thiophosphotyrosine Peptides

No Abstract     

光学活性甲苄菊酯的合成及其结构与活性关系的研究

本文改进了Goffinet方法,完成了(±)-trans菊酸的拆分;改进了Campbel?方法,只用一种拆分剂(奎宁)完成了对(±)-cis菊酸的拆分。用IR、~1HNMR、旋光度测定等方法确定了各甲苄菊酯光学异构体的结构。生物试验表明结构与活性有如下关系:1,各异构体中以1R-酯的杀虫活性为高,尤其(-)-(1R,3R)-trans甲苄菊酯对全部测试昆虫均显示较高的杀虫活性;2,昆虫不同,各异构体的活性次序也略有差异。     

一种新的库仑微水滴定仪的设计方法

在传统微库仑滴定仪原理的基础上，利用８７５１单片机和微机，采用对电解电流时间调制的方法以及测量精度为准则判断滴定终点，从而大大地提高了仪器的测量精度和重复性。     

Kinetic and thermodynamic studies on ligand substitution reactions and base-on/base-off equilibria of cyanoimidazolylcobamide, a vitamin B12 analog with an imidazole axial nucleoside

Ligand substitution reactions of the vitamin B12 analog cyanoimidazolylcobamide, CN(Im)Cbl, with cyanide were studied. Cyanide substitutes imidazole (Im) in the alpha-position more slowly than it substitutes dimethylbenzimidazole in cyanocobalamin (vitamin B12). The kinetics of the displacement of Im by CN- showed saturation behaviour at high cyanide concentration; the limiting rate constant was found to be 0.0264 s(-1) at 25 degrees C and is characterized by the activation parameters: DeltaH(not =) = 111 +/- 2 kJ mol(-1), DeltaS(not =) = +97 +/- 6 J K(-1) mol(-1), and DeltaV(not =) = +9.3 +/- 0.3 cm3 mol(-1). These parameters are interpreted in terms of an I(d) mechanism. The equilibrium constant for the reaction of CN(Im)Cbl with CN- was found to be 861 +/- 75 M(-1), which is significantly less than that obtained for the reaction of cyanocobalamin with CN- (viz. 10(4) M(-1)). pKbase-off for the base-on/base-off equilibrium was determined spectrophotometrically and found to be 0.99 +/- 0.05, which is about 0.9 pH units higher than that obtained previously in the case of cyanocobalamin. In addition, the kinetics of the base-on/base-off reaction was studied using a pH-jump technique and the data obtained revealed evidence for an acid catalyzed reaction path. The results obtained in this study are discussed in reference to those reported previously for cyanocobalamin.     

Enzymatic reaction of the immobilized enzyme on porous silicon studied by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a matrix-free technique that allows for the direct desorption/ionization of low-molecular-weight compounds with little or no fragmentation of analytes. This technique has a relatively high tolerance for contaminants commonly found in biological samples. DIOS-MS has been applied to determine the activity of immobilized enzymes on the porous silicon surface. Enzyme activities were also monitored with the addition of a competitive inhibitor in the substrate solution. It is demonstrated that this method can be applied to the screening of enzyme inhibitors. Furthermore, a method for peptide mapping analysis by in situ digestion of proteins on the porous silicon surface modified by trypsin, combined with matrix-assisted laser desorption/ionization-time of flight-MS has been developed.