Synthesis and Antibacterial Activity of New Tetracyclic Triazolo-thiadiazino Fluoroquinolones

Since nalidixic acid1 was first clinically used as a potent antibacterial agent, many analogues, such as bicyclic ciprofloxacin2, tricyclic ofloxacin3, have become an important class of therapeutical compounds. Recently, novel tetracyclic fluoroquinolones having a thiazolooxazine ring with potent antibacterial activity against both G+ and G- have been reported4. In order to find better antibacterial agents for our urgent research of the multidrug resistant (MDR)5, we herein describe a facil…     

Synthesis of Tetrahydropyridinyltriazolothiadiazines as Possible Muscarinic Agonists

4-Amino-5-(pyridin-3-yl)-4H-l,2,4-triazole-3-thiol 1 were condensed with 2-bromo-l-(substituted phenyl)ethanone to give pyridinyltriazolothiadiazines 2a-c, which were quaternarized with methyl iodide and oxidized with 30 % hydrogen peroxide to afford the corresponding methyl pyridinium salts 3a-c and pyridine- 1 -oxides 4a-c, respectively. The redtiction of compounds 3 and 4 with NaBH4 in methanol produced the target compounds 1-methyl- 1.2.5.6-tetrahydropyridin-3-yl)-6-aryl-s-triazolothiadiazines 5a-c and 3-( l-hydroxyl- 1, 2, 5, 6-tetrahydropyridin -3-yl)-6-aryl-s-triazolothiadiazines 6a-c, respectively. The endothelium vascular relaxing activity of the target compounds was screened.     

Synthesis and antitumor activity of water-soluble poly(aminoheterocyclic amine)s (I): N,N,N'''',N''''-tetra[2-(4-amino-5-substituted-s-triazol-3-yl sulfanyl)ethyl] -1,4-benzyldiamine salts

Five water-soluble poly(aminoheterocyclic amine)s containing s-triazole ring were synthesized as respective HC1 salts (5a-5e). Biological activities in L1210 (murine leukemia) and Chinese hamster ovary (CHO) cell lines were investigated via IC50 cytotoxicity determinations. The tide compounds represented moderate cytotoxicity (low IC50 values between 15 and 68μmol/L) in L1210 but high cytotoxicity (lower IC50 values: 0.25,0.018,0.014μmol/L for Sa-5e, respectively) in CHO cell lines, while the corresponding HC1 salts of the intermediates (3a-3e) without polyamine tether and starting materials amino-s-triazoles (1a-1e) showed poor or no activities against the above cell lines.     

全光纤多模速度干涉仪的研究

针对传统全光纤单模速度干涉仪在爆炸冲击试验中,前端的单模准直器对高速运动的物体的漫反射光难以有效收集,提出了全光纤多模速度干涉仪的装置。利用超辐射发光二极管作为光源,初步验证了全光纤多模速度干涉仪的可行性。主要阐述了全光纤多模速度干涉仪的原理和结构,并将其与全光纤单模速度干涉仪在喇叭振动速度的实验中进行比较,取得了一致的结果,最后还进行霍普金森压杆撞击实验,实测的速度最大值为10.49 m/s,与理论值10 m/s符合较好。     

基于载流子选择性接触的N型晶硅电池钝化特性研究

为了研究载流子选择性接触结构在N型晶硅电池钝化特性,本文设计了专门的材料结构.分析对比了不同掺杂浓度分布的材料结构在退火后、沉积SiNx:H薄膜后及烧结后隐开路电压值的变化,并对其钝化机理进行了分析.研究结果表明隐开路电压值对掺杂浓度分布非常敏感.随着掺杂浓度分布进入硅基体的"穿透"深度增加,相对应地退火后、SiNx:H薄膜沉积后及烧结后隐开路电压值均呈现先增加后减小的趋势,且样片沉积SiNx:H薄膜后隐开路电压的增加幅度也逐渐减小,而样片烧结后隐开路电压值又出现不同幅度的下降,且隐开路电压值的下降幅度逐渐减小.通过适当的掺杂工艺,可以使得烧结后的隐开路电压均值达到738 mV.     

基于可视化荷载路径的结构混凝土拉-压杆模型

通过荷载路径可以直观地了解结构实现其功能的方式。本文首先根据荷载路径的定义，介绍一种基于平衡原理，将有限元方法和流线追踪算法结合，确定二维线弹性结构中荷载路径的方法。采用这种方法结合商用有限元软件Algor13和商用数据处理软件Tecplot9．0，把前者得到的结构应力计算结果及对应的有限元网格信息通过数据文件输入后者，以得到结构内连续的可视化荷载路径。最后，本文将这种方法用于确定牛腿结构中的可视化荷载路径，并在此基础上建立该结构的拉杆-压杆模型。     

Side-chain H and C resonance assignment in protonated/partially deuterated proteins using an improved 3D(13)C-detected HCC-TOCSY

We propose the use of (13)C-detected 3D HCC-TOCSY experiments for assignment of (1)H and (13)C resonances in protonated and partially deuterated proteins. The experiments extend 2D C-13-start and C-13-observe TOCSY type experiments proposed earlier. Introduction of the third (1)H dimension to 2D TOCSY: (i) reduces the peak overlap and (ii) increases the sensitivity per unit time, even for highly deuterated (>85%) protein samples, which makes this improved method an attractive tool for the side-chain H and C assignment of average sized proteins with natural isotope abundance as well as large partially deuterated proteins. The experiments are demonstrated with a 16 kDa (15)N, (13)C-labeled non-deuterated apo-CcmE and a 48 kDa uniformly (15)N, (13)C-labeled and fractionally ( approximately 90%) deuterated dimeric sFkpA. It is predicted that this method should be suitable for the assignment of methyl (13)C and (1)H chemical shifts of methyl protonated, highly deuterated and (13)C-labeled proteins with even higher molecular weight.     

Simultaneous quantification and identification of individual chemicals in metabolite mixtures by two-dimensional extrapolated time-zero (1)H-(13)C HSQC (HSQC(0))

Quantitative one-dimensional (1D) (1)H NMR spectroscopy is a useful tool for determining metabolite concentrations because of the direct proportionality of signal intensity to the quantity of analyte. However, severe signal overlap in 1D (1)H NMR spectra of complex metabolite mixtures hinders accurate quantification. Extension of 1D (1)H to 2D (1)H-(13)C HSQC leads to the dispersion of peaks along the (13)C dimension and greatly alleviates peak overlapping. Although peaks are better resolved in 2D (1)H-(13)C HSQC than in 1D (1)H NMR spectra, the simple proportionality of cross peaks to the quantity of individual metabolites is lost by resonance-specific signal attenuation during the coherence transfer periods. As a result, peaks for individual metabolites usually are quantified by reference to calibration data collected from samples of known concentration. We show here that data from a series of HSQC spectra acquired with incremented repetition times (the time between the end of the first (1)H excitation pulse to the beginning of data acquisition) can be extrapolated back to zero time to yield a time-zero 2D (1)H-(13)C HSQC spectrum (HSQC(0)) in which signal intensities are proportional to concentrations of individual metabolites. Relative concentrations determined from cross peak intensities can be converted to absolute concentrations by reference to an internal standard of known concentration. Clustering of the HSQC(0) cross peaks by their normalized intensities identifies those corresponding to metabolites present at a given concentration, and this information can assist in assigning these peaks to specific compounds. The concentration measurement for an individual metabolite can be improved by averaging the intensities of multiple, nonoverlapping cross peaks assigned to that metabolite.     

t-ZrO2/α-Al2O3超细晶复合粉体的低温燃烧合成

以Al(NO3)3*9H2O、ZrO(NO3)2*2H2O和Y(NO3)3*6H2O为原料,采用低温燃烧合成(LCS)法制备了多种不同ZrO2/Al2O3比的复合粉体,对其物相和形貌进行了表征.实验结果表明,采用LCS法在400℃合成的t-ZrO2/α-Al2O3复合粉体晶粒超细,其结晶程度随ZrO2/Al2O3比的增加逐渐降低,晶粒大小也随ZrO2/Al2O3比的变化而有规律地变化.     

Reason for the loss of hydrophilicity of TiO_2 film and its photocatalytic regeneration

TiO2 film was prepared on soda-lime glass by sol-gel method. The water contact angle (θ) of the fresh TiO2 film is 0°. During storage in air, the surface of TiO2 film is gradually converted to the hydrophobic state. XPS and ITD results reveal that it is due to the adsorption of organic contaminants on TiO2 surface in air ambience. The lost hydrophilicity of TiO2 film can be regenerated by UV illumination.