磁场效应下分子发光行为的研究 Ⅰ.用磁场效应抑制溶剂散射光的波动

△同步荧光法可使荧光谱带窄化而达到提高荧光分析法的选择性。通常在进行同步扫描时采用较小的△λ值(λ_(em)-λ_(ex)),这时溶剂散射光的干扰严重。广义地,散射光可分为两部分:一是散射光的总水平;一是散射光的波动。二者抑制其一均可提高同步荧光法的检测灵敏度。我们曾用偏振技术抑制散射光总水平。但散时光波动的抑制技术尚未见报道。本文提出用磁场效应(Magnctic field Effects.MFE)抑制共振同步荧光扫描(△λ=0)中溶剂散射光波动。结果表明,该技术简便可行。如对乙醇散射光的波动可抑制到原来的2％

Suppressing the Undulation of Solvent Scattering Light by Constant Magnetic Field

Synchronous fluorometry can cause a band-narrowing effect to improving the fluorometric selectivity (Fig. 1). However, since the △λ value selected is usually small (generally about 0—5 nm) in synchronous scanning, the interference of solvents scattering light (mainly Rayleigh scattering light) is so serious that the sensitivity and the detection limit are harmed greatly. Generall

恒磁场效应对溶剂散射光波动的抑制

同步荧光法可使荧光谱带窄化,因而可大大提高荧光分析法的选择性(见图1).通常在进行同步扫描时所采用的发射与激发波长差△λ值较小(一般为0—5nm),导致溶剂散射光(主要是瑞利散射)对同步荧光信号的严重干扰,从而大大损害了分析灵敏度与检测限.广义地说,溶剂的散射光可分为两部分:一是散射光的总水平;另一是散射光的波动.二者抑制其一均可提高方法的检测灵敏度.我们曾报道,根据散射光与荧光的偏振性质的差异采用偏

Dimer coverings on random multiple chains of planar honeycomb lattices

We study dimer coverings on random multiple chains. A multiple chain is a planar honeycomb lattice constructed by successively fusing copies of a 'straight' condensed hexagonal chain at the bottom of the previous one in two possible ways. A random multiple chain is then generated by admitting the Bernoulli distribution on the two types of fusing, which describes a zeroth-order Markov process. We determine the expectation of the number of the pure dimer coverings (perfect matchings) over the ensemble of random multiple chains by the transfer matrix approach. Our result shows that, with only two exceptions, the average of the logarithm of this expectation (i.e., the annealed entropy per dimer) is asymptotically nonzero when the fusing process goes to infinity and the length of the hexagonal chain is fixed, though it is zero when the fusing process and the length of the hexagonal chain go to infinity simultaneously. Some numerical results are provided to support our conclusion, from which we can see that the asymptotic behavior fits well to the theoretical results. We also apply the transfer matrix approach to the quenched entropy and reveal that the quenched entropy of random multiple chains has a close connection with the well-known Lyapunov exponent of random matrices. Using the theory of Lyapunov exponents we show that, for some random multiple chains, the quenched entropy per dimer is strictly smaller than the annealed one when the fusing process goes to infinity. Finally, we determine the expectation of the free energy per dimer over the ensemble of the random multiple chains in which the three types of dimers in different orientations are distinguished, and specify a series of non-random multiple chains whose free energy per dimer is asymptotically equal to this expectation.NSFC [10831001, 11061027

Chiral Separation of Rosiglitazone Sodium by Aqueous/Nonaqueous Capillary Electrophoresis

以环糊精及其衍生物为手性选择剂,通过优化缓冲液的浓度、酸度以及采用环糊精的种类和浓度等,建立了罗格列酮钠对映体的水介质和非水介质两种毛细管电泳拆分方法。最佳条件为:150 mmol/LTris-H3PO4缓冲液,pH=2.0,含有1 mmol/Lβ_CD或DM_β_CD,10%(φ)甲醇的运行液,分离电压为25 kV,检测波长215 nm。也可以使用含有9 mmol/L HDMS_β_CD,20 mmol/L磷酸和10 mmol/L NaOH的甲醇电泳液。两种拆分体系均实现了罗格列酮钠对映体的基线分离,而且拆分效率基本相当。方法简便、快速,可作为罗格列酮钠的手性分离方法。HPCE methods for separating and determining the rosiglitazone sodium enantiomers were estabˉlished.The effects of buffer concentration,pH,and the type and concentrations of CDs in the chiral separaˉtion of rosiglitazone sodium were investigated.The buffer solution used in aqueous capillary electrophoresis(ACE)was150mmol/L Tris-H 3 PO 4 solution,pH=2.0,containing1mmol/Lβ-CD or DM-β-CD,and10%(φ)methanol.The voltage applied was25kV,and the detective wavelength was215nm.In addiˉtion,a simple method for the separation of rosiglitazone sodiumenantiomers was described by nonaqueous capˉillary electrophoresis(NACE)after establishing suitable separation conditions.Under the experiment condiˉtions adopted,the baseline separation of rosiglitazone sodium enantiomers was obtained by the two methods.The proposed methods were simple,rapid and accurate,and could be used for the chiral separation of rosiglitaˉzone sodium

异基因造血干细胞移植患者发生口腔黏膜炎的危险因素分析

目的】探讨进行异基因造血干细胞移植（allo-HSCT）患者口腔黏膜炎（OM）的发生及其危险因素。【方法】回顾分析1996年5月至2007年3月在我院治疗的75例恶性血液病患者allo-HSCT的临床资料,分析相关因素与口腔黏膜炎发生的关系。【结果】49例（65.0%）患者发生口腔黏膜炎,其中13例（26.5%）发生Ⅲ度,14例（28.6%）发生Ⅳ度,中位发生时间移植后第5（3～8）天。单因素分析显示,患者年龄、疾病种类、移植方式与口腔黏膜炎的发生无相关性（P〉0.05）,TBI/CY（全身照射＋环磷酰胺）预处理的患者口腔黏膜炎发生率高于BU/CY（白消安＋环磷酰胺）方案（78.3%vs 59.6%,P〈0.05）,口服剂型白消安口腔黏膜炎发生率高于静脉剂型（91.2%vs 11.1%,P〈0.001）,无四氢叶酸钙（CF）解救甲氨蝶呤（MTX）口腔黏膜炎明显高于CF解救（87.0%vs 9.5%,P〈0.001）。多因素回归分析结果表明,只有含TBI预处理方案（OR=3.6,P〈0.05）、口服剂型白消安（OR=2.9,P〈0.01）、无CF解救MTX（OR=17.1,P〈0.001）是all-HSCT患者口腔黏膜炎发生的独立影响因素。【结论】使用静脉剂型BU联合CY预处理方案、CF解救MTX的患者allo-HSCT后口腔黏膜炎发生率明显减少