Fabrication of inorganic-organic hybrid based on polyoxometalate SiW10Fe2 and folate as peroxidases for colorimetric immunoassay of cancer cells

Fabrication of folate and iron-substituted polyoxometalate(（FeOH₂）₂SiW₁₀O₃₆]to form nanoparticles （FA-SiWFe₂） has been achieved.This inorganic-organic hybrid possesses intrinsic peroxidase-like activity,which could be used in detection of cancer cells in colorimetric multiplexed immunoassay.     

Cytotoxic metabolites from the soil-derived fungus Exophiala pisciphila

A new polyketide compound 1 and a new naturally occurring chromone derivative 2, along with two known indole alkaloids 3-4 were characterized from the ethyl acetate extract of a soil-derived fungal strain, Exophiala pisciphila PHF-9. The structures of compounds 1-4 were established by detailed spectroscopic analysis and comparison with literature data. The absolute configuration of 1 was determined by a modified Mosher's method. Compound 1 exhibited moderate cytotoxicity against A-549, Hela, PANC-28 and BEL-7402 cell lines.     

低硼富含有机质的河/雨水正热电离硼同位素的测定

对低硼富含有机质的河/雨水样品硼的分离方法及硼同位素组成的测定进行了研究.采用硼特效树脂富集河/雨水样品,结合微升华技术去除有机质;采用正热离子质谱法进行硼同位素组成的测定.全流程回收率在97.50%～101.17%之间,测试数据和多接受电感耦合等离子体质谱比较接近,测试精度小于0.05‰.经本方法处理后的样品能满足同...     

脉冲熔融-飞行时间质谱法测定金属材料中氧、氮、氢和氩

采用自主研制的脉冲熔融飞行时间质谱法可以固时测定金属中O,N,H和Ar.重点讨论质谱谱线的选择,信号获得以及数据处理和校准,并给出O,N,H和Ar 4种的检出限分别为0.021,0.060,0.002和0.002 μg/g,线性范围分别为0.070～500 μg/g,0.200～400 μg/g,0.006～40 μg...     

Competition between weak localization and antilocalization in topological surface states

A magnetoconductivity formula is presented for the surface states of a magnetically doped topological insulator. It reveals a competing effect of weak localization and weak antilocalization in quantum transport when an energy gap is opened at the Dirac point by magnetic doping. It is found that, while random magnetic scattering always drives the system from the symplectic to the unitary class, the gap could induce a crossover from weak antilocalization to weak localization, tunable by the Fermi energy or the gap. This crossover presents a unique feature characterizing the surface states of a topological insulator with the gap opened at the Dirac point in the quantum diffusion regime.     

菠萝蛋白酶催化大豆蛋白水解反应的热动力学

利用热活性检测仪测定了菠萝蛋白酶催化大豆蛋白水解反应的热功率-时间曲线,按照热动力学理论和对比进度法解析出不同温度、酸度时菠萝蛋白酶催化大豆蛋白水解反应的米凯利斯常数（K_m）和最大速率（V_max）,并建立了K_m与温度和酸度的关系式,从而获得酶催化反应的最适温度（314.63 K）和最适pH（6.99）. 在最适温度和最适pH条件下,测定了金属离子可逆竞争时菠萝蛋白酶催化大豆蛋白水解反应的热功率-时间曲线,对曲线进行处理,得到了酶催化反应的米凯利斯常数（K_m’）和最大速率（V_max’）. 建立了K_m’与金属离子浓度间的关系式,比较了金属离子对酶催化反应的激活或抑制效果.     

环丙烷基三甲基硅醚类化合物的脱硅基及酯化反应的研究

环丙烷基硅醚在卤化锌的作用下能够与硅胶反庆生成环丙基醇。研究了环丙烷基硅醚在卤化锌作用下与酰氯发生的酯化反应,发现在配位性较弱的溶剂二氯甲烷中,可得到比在乙醚中更高的产率。此外,采用一锅煮的方法,从烯醇硅醚出发,经过环丙化反应、酯化反应,以较好的产率合成了环丙基酯。     

新型含吲哚环酯类化合物的合成、抑藻活性及构效关系研究

从苔藓虫Zoobotryon pellucidum中提取的2,5,6-三溴-1-甲基芦竹碱(TBG)能较好地抑制海洋生物藤壶的附着. 为提高该类化合物在防污涂料中的复配性能, 合成了4个新型的不同卤素取代和N-取代且具有较好亲脂性能的TBG类似物. 通过1H NMR, 13C NMR, IR和元素分析对目标化合物6a～6d进行了结构表征. 生物实验结果表明, 化合物5～6对海藻Nitzschia closterium均具有较好的生长抑制活性, 其中以亲脂性较强的6b和6d抑制作用最为显著, LC50分别可达1.33 µg/mL和1.06 µg/mL. 对化合物的定量构效关系进行了初步探讨.     

Three new flavans in dragon's blood from Daemonorops draco

Three new flavans were isolated from chloroform extracts of dragon's blood from Daemonorops draco, together with eight known compounds. The structures of the new flavans were determined by 1D and 2D NMR spectroscopic analysis. These compounds are the first examples of 2-methoxyflavans from D. draco and regarded as derivatives of biogenetic intermediates from flavans to chalcones, which are characteristic of the dragon's blood.     

Nearly noninvasive readout and manipulation of spin in double quantum dot using spin bias

Dynamics of two quantum dots coupled to electrodes with spin bias is investigated theoretically by means of the master equations. The two dots are coupled via exchange interaction. When the exchange interaction is much smaller than the lead-dot 2 coupling and dot 2 is under a symmetric spin bias, an initially fully polarized electron spin in dot 1 undergoes an oscillation with ignorable attenuation. Meanwhile, the direction of charge current flowing through dot 2 oscillates in the same period as that of the spin in dot 1. This allows to reverse or nearly noninvasively read out the spin in dot 1, by switching on and off the exchange interaction for a duration of half-integer or integer periods of the oscillation, respectively.