Preparation and characterization of the inclusion complex of Ofloxacin with ��-CD and HP-��-CD

The formation of the inclusion complexes of Ofloxacin with cyclodextrins (CDs) including ??-cyclodextrin (??-CD), and hydroxypropyl-??-cyclodextrin (HP-??-CD) were studied by Fluorescence, UV?CVis absorption spectroscopy and nuclear magnetic resonance spectroscopy (NMR) in solution. Experimental conditions including the concentration of various CDs and media acidity were investigated in detail at room temperature. The results suggested that in different pH solutions, CDs have different inclusive capacity to different forms Ofloxacin. ??-CD was most suitable for inclusion of neutral form and HP-??-CD was suitable for acidic form. The binding constant (K) of the inclusion complex was determined by fluorescence measurement, and the complexation ratio was determined as 1:1 in the concentration range used in this study. A mechanism was proposed to explain the inclusion process based on the experimental NMR data.     

Synthesis, Crystal Structure and Fluorescence Property of a Binuclear Zn(II) Complex: [Zn2(μ-N3)2(N3)2(L)2] [L?=?1-(1,10-phenanthrolin-2-yl)-2-pyridone]

Abstract  Hydrated zinc perchlorate reacted with sodium azide and 1-(1,10-phenanthrolin-2-yl)-2-pyridone (L) in methanol solution and resulted in the formation of a new binuclear complex: [Zn₂(μ-N₃)₂(N₃)₂(L)₂]. The complex has been characterized by elemental analysis and IR spectrum, and its crystal structure determined by X-ray crystallography and the complex crystallizes in the monoclinic system with space group P2₁/c and a = 11.409(2), b = 8.0733(15), c = 18.163(3) Ǻ, β = 99.095(3)°. In the complex two azide anions act as bridge ligand and another two azide anion and two 1-(1,10-phenanthrolin-2-yl)-2-pyridone function as terminal ligands, and Zn(II) ion lies in a distorted triangle bipyramid geometry. Index Abstract  The title binuclear Zn(II) complex was synthesized by zinc perchlorate, sodium azide and 1-(1,10-phenanthrolin-2-yl)-2-pyridone and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that azide anion function as both bridge ligand and terminal ligand, and 1-(1,10-phenanthrolin-2-yl)-2-pyridone only acts as a terminal ligand.      

铋膜电极溶出伏安法测定苍耳子中锌的含量

采用电位溶出法,用铋膜电极替代汞膜电极对中药苍耳子中微量元素锌的测定作了研究,考察了同位镀铋膜及测定微量元素锌的条件。实验结果表明：锌在以KSCN为支持电解质的铋膜电极上可得到灵敏的电位溶出峰,线性方程为：为I=2.0062C＋0.0069,相关系数为r=0.9967,检出限为6.0×10-8g/L线性范围为0.5×10-6—2.8×10-6mol/L,RSD=2.24%。该法简单快速,准确度和精密度均符合要求,回收率为89.5%—100.3%。     

扇贝多肽经由aSMase-JNK通路抑制UVA诱导HaCaT细胞凋亡

建立紫外线A(UVA)辐射损伤HaCaT细胞的病理模型, 从酸性鞘磷脂酶-JNK信号通路的角度研究扇贝多肽(Polypeptide from Chlamys farreri, PCF)抑制UVA诱导HaCaT细胞凋亡的分子机制. 采用Hoechst 33258染色结合琼脂糖凝胶电泳分析细胞凋亡; 用RT-PCR法和细胞免疫荧光染色检测胞内酸性鞘磷脂酶(acid sphingomyelinase, aSMase)的表达; 蛋白印迹法检测细胞内JNK及磷酸化JNK的蛋白水平. 结果表明, PCF可明显地抑制UVA诱导的HaCaT细胞凋亡; aSMase抑制剂Desipramine和JNK抑制剂SP600125均可阻断UVA引起的细胞凋亡; PCF的浓度在1.42~5.68 mmol/L范围内可依赖性地抑制UVA辐射后细胞内aSMase的表达量以及JNK蛋白的磷酸化; 预先加入Desipramine则抑制UVA引起的JNK蛋白的磷酸化. 表明PCF通过阻断aSMase-JNK通路来抑制UVA诱导HaCaT细胞凋亡.     

高阶中立型微分方程的周期解

本文采用Ｆｏｕｒｉｅｒ级数理论,获得了任意阶常系数中立型微分方程周期解存在性和唯一性的充分必要条件     

Eventually positive solutions of odd order neutral differential equations

The odd order neutral differential equations are considered. New necessary and sufficient conditions, and comparison theorems of existence of eventually positive solutions are obtained. Nonexistence criteria of eventually positive solutions are also established.     

串联双柱固相萃取-气相色谱-串联质谱法检测茶叶中拟除虫菊酯

建立了气相色谱-串联质谱定量检测花茶、绿茶、红茶和黑茶4类茶叶中氟氯氰菊酯、氯氰菊酯和氰戊菊酯3种拟除虫菊酯农药残留量的方法。样品采用乙腈进行提取,优化洗脱液配比,选择Carb/NH2和SLH双柱串联净化富集。采用外标法定量,30 min内完成农药残留检测。3种拟除虫菊酯的检出限分别为0.4、1.0和0.3μg/kg,在0.05~2.00 mg/kg内线性关系良好,相关系数均大于0.999。在0.10、0.50和2.00 mg/L 3个添加水平下,空白加标样品的回收率为80.6%~116.3%。茶叶实际样品检测结果的日内相对标准偏差(RSD)为1.3%~12.6%,日间RSD为2.7%~12.1%。该法操作简单,重现性好,适用于茶叶中拟除虫菊酯类农药残留的检测。     

OSCILLATION THEOREMS FOR SECOND ORDER NEUTRAL DIFFERENCE EQUATIONS

The aim of this paper is to study the oscillation of second order neutral difference equations.Our results are based on the new comparison theorems,that reduce the problem of the oscillation of the second order equation to that of the first order equation.The comparison principles obtained essentially simplify the examination of the equations.     

Crystal Structure and Superoxide Dismutase Activity of [Cu(ethylenediamine) 2Cl][PF 6]

The preparation, spectroscopic properties, and crystal structure of chlorobis(ethylenediamine)copper(II) hexafluorophosphate [Cu(en)₂Cl][PF₆], (en=ethylendiamine) are reported. The complex crystallizes in the monoclinic system, space group P2₁/c, with cell constants a=6.1488(9) Å, b=12.696(2) Å, c=17.7424(17) Å, =97.265(12)°, and Z=4. The copper(II) ion is coordinated to two bidentate en molecules, to one chlorine ion, and to a more distant fluorine atom of the PF₆ group, leaving the copper ion in a distorted octahedral coordination geometry. The superoxide dismutase mimetic activity of the complex was investigated using the indirect xanthine-xanthine oxidase- nitroblue tetrazolium method and compared to that of the native enzyme.     

Synthesis and Crystal Structure a Two-Dimensional Coordination Polymer: [Cd( μ -N3)( μ -HL)(H2O)]n [HL?=?Monodeprotonated 2,2′-bypyridine-3,3′-diol]

Abstract  Hydrated cadmium perchlorate reacted with sodium azide and 2,2′-bypyridine-3,3′-diol (H₂L) in ethanol solution and resulted in the formation of a two-dimensional coordination polymer: [Cd(μ-N₃)(μ-HL)(H₂O)]_n. The complex has been characterized by elemental analysis and IR spectrum, and its crystal structure determined by X-ray crystallography and the complex crystallizes in the monoclinic system with space group P2₁/c and a = 7.2849(14), b = 9.9568(19), c = 17.058(3) Ǻ, β = 102.254(2)°. In the complex both azide anion and monodepronated 2,2′-bypyridine-3,3′-diol anion (HL) act as bridge ligands and led to the formation of a two-dimensional sheet structure on (100) plane, and the O–H⋯N hydrogen bond made the sheets pile up along [100] direction, which forms a supramolecular three-dimensional structure. Graphical Abstract  The title two-dimensional Cd(II) coordination polymer was synthesized by cadmium perchlorate, sodium azide and 2,2′-bypyridine-3,3′-diol and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that the two-dimensional coordination polymer was fabricated with azide anion and monodeprotonated 2,2′-bypyridine-3,3′-diol as mixed bridge ligands.