Promoting the formation and stabilization of G-quadruplex by dinuclear RuII complex Ru2(obip)L4

The remarkable ability of a new dinuclear Ru (II) complex Ru 2(obip)L 4 [obip = 2-(2-pyridyl)imidazo[4,5- f][1,10]-phenanthroline; L = 2,2'-bipyridine] to promote the formation and stabilization of the human telomeric repeat AG3(T2AG3)3 quadruplex was reported. The experimental results indicated that Ru 2(obip)L 4 could induce the formation of an antiparallel G-quadruplex structure in the absence of metal cations. It could induce positive T m shifts of +9.4 and +5.8 degrees C in Na (+) and K (+) buffers, respectively, in which an increase in the melting temperature of the quadruplex indicated a stabilizing effect. Binding stoichiometry with the quadruplex was investigated through a luminescence-based Job plot. The major inflection point for Ru 2(obip)L 4 at x = 0.48 was observed. The data were consistent with a 1:1 [quadruplex]/[complex] binding mode, which was suggestive of a specific Ru 2(obip)L 4-quadruplex interaction with a single guanine tetrad.     

PP/LDPE共混体系的辐射效应

研究了在多官能团单体—三烯丙基异氰脲酸酯存在下ＰＰ／ＬＤＰＥ共混体系接受γ－辐射的效果。用溶解度参数和ＴＥＭ技术评估了共混体系的相容性与多官能团单体在共混体系中的分布，并用ＳＥＭ、ＤＳＣ、动态力学等方法对共混体系相容性进行了表征。结果表明，ＰＰ／ＬＤＰＥ是不相容的共混体系，三烯丙基异氰脲酸酯主要分布在共混体系的相界面区域，辐照强化了共混体系的相间结合，增加了界面厚度，改善了共混体系的相容性。     

Highly stereoselective synthesis of (Z)-3-methoxy-1-methyleneisoindoles via DMAP catalyzed cyclization of methyl 2-alkynylbenzimidates

A DMAP (4-dimethylaminopyridine) catalyzed cyclization of methyl 2-alkynylbenzimidates has been developed, which affords 3-methoxy-1-methyleneisoindoles with excellent Z-stereoselectivity under mild and transition-metal-free conditions. The (Z)-3-methoxy-1-methyleneisoindole products can be converted to corresponding 3-amino-1-methyleneisoindoles, 3-methoxy-isoindoles, 3-methyleneisoindolinones and isoindolinones with high efficiency.     

Total synthesis of methyl protodioscin: a potent agent with antitumor activity

Methyl protodioscin (1), otherwise known as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22-methoxy-25(R)-furost-5-ene-3 beta,26-diol, has been synthesized for the first time from diosgenin through nine steps in an overall yield of 7.8%.     

高效液相色谱法检测人肝组织中黄曲霉毒素

以人肝癌组织为研究材料,丙酮、氯仿为主要抽提溶剂,建立了用高效液相色谱技术检测肝组织中黄曲霉毒素Ｂ＿１的方法。采用μ－Ｐｏｒａｓｉｌ色谱往,氯仿、环己烷、乙腈、异丙醇为流动相,荧光检测器检测,激发波长３６５ｎｍ,发射波长４３５ｎｍ。方法的平均回收率为９６．８５％,变异系数为４．５２％,最低检测限为０．０５ｎｇ。１０例肝癌组织中有７例检出５。４９～７３．７０ｎｇ／ｇ不等的黄曲霉毒素Ｂ＿１。方法快速、准确、灵敏度高。     

Large-signal results for degenerate four-wave mixing and phase conjugate resonators

A numerical calculation procedure and various large-signal numerical solutions are presented for degenerate four-wave mixing in optical Kerr media, and for phase conjugate resonators using degenerate four-wave mixing. The solutions presented take full account of nonlinear refractive index changes, pump depletion, signal saturation, distributed losses, and possible external mirrors with laser gain. We find that including the nonlinear index change generally causes little change in the reflectivity or power output of degenerate four-wave mixing devices, at least with symmetric pumping. The optimum power output from a phase conjugate resonator with and without a laser gain medium is calculated. The results provide some theoretical guidance for designing phase conjugate resonators.     

聚酰亚胺薄膜表面粗糙度的影响因素

 采用热蒸发气相沉积聚合方法（VDP）制备了聚酰亚胺(PI)薄膜,研究了设备、衬底温度、升温过程和单体配比因素对PI薄膜表面形貌的影响。利用干涉显微镜和扫描电镜对薄膜表面形貌进行了分析;利用原子力显微镜测定了薄膜表面粗糙度。结果表明：设定蒸发源-衬底距离为74 cm时可成连续膜;蒸发源采用一段升温和多段升温时,膜表面均方根粗糙度分别为291.23 nm和61.99 nm;采用细筛网可防止原料的喷溅;均苯四甲酸二酐和4,4′-二氨基二苯醚（PMDA和ODA）单体沉积速率比值为0.9∶1时,膜表面均方根粗糙度值可减小至3.30 nm;沉积衬底温度保持30 ℃左右时,膜表面均方根粗糙度为4.01 nm, 随温度的上升,膜表面质量会逐渐变差。     

高功率准连续激光二极管抽运的Nd：YVO4激光器

对高功率准连续激光二极管端面抽运的Nd:YVO4固体激光器进行了实验研究。研究了抽运功率、温度、重复率及输出镜的透过率对激光器输出功率的影响。当激光二极管重复率达到720Hz、抽动功率33.2W时,激光输出最大平均功率为11W。     

3.6-W cryogenic Tm,Ho:YLF laser pumped by fiber-coupled diodes module

In this paper, we report a high power cryogenic cooling Tm(6 at.-%),Ho(0.5 at.-%):YLF laser end-pumped by a 19-fiber-coupled-diodes module with the central wavelength of 792 nm at 20°. The highest continuouswave power of 3.6 W at 2.051 μm is attained under pumping power of 13.6 W, corresponding to opticaloptical conversion efficiency of 26%, and the slope efficiency is larger than 30%. The threshold power is only about 0.16 W because of the long lifetime, large effective emission cross section, and low re-absorption in Tm,Ho:YLF crystal.     

Dynamical properties of the Haldane chain with bond disorder

By using Lanczos exact diagonalization and quantum Monte Carlo combined with stochastic analytic continuation, we study the dynamical properties of the S = 1 antiferromagnetic Heisenberg chain with different strengths of bond disorder. In the weak disorder region, we find weakly coupled bonds which can induce additional low-energy excitation below the one-magnon mode. As the disorder increases, the average Haldane gap closes at δ_∆ ~ 0.5 with more and more low-energy excitations coming out. After the critical disorder strength δ_c ~ 1, the system reaches a random-singlet phase with prominent sharp peak at ω = 0 and broad continuum at ω > 0 of the dynamic spin structure factor. In addition, we analyze the distribution of random spin domains and numerically find three kinds of domains hosting effective spin-1/2 quanta or spin-1 sites in between. These “spins” can form the weakly coupled longrange singlets due to quantum fluctuation which contribute to the sharp peak at ω = 0.