2000 Vol.11 No.8 P.Preparation of AChE Inhibitors From Jujubogenin

A dammarane derivative dihydrojujubogenin-2-en-1-one, which possesses a skeleton and pharmacophore partially similar to those of Territrem B, a potent AChE inhibitor, was synthesized via three different paths. The anti-AChE activity of this compound and related analogue was measured.     

噻吩基和呋喃基四硫富瓦烯的合成及电化学性质

提供了一种合成噻吩基和呋喃基四硫富有瓦烯（ＴＴＦ）的方法，并用其合成了３种未见文献报道的噻吩基ＴＴＦ（Ⅶａ，Ⅷｂ，Ⅶｃ）和２种呋喃基ＴＴＦ（Ⅶｄ１，Ⅶｄ２）研究这些化合物的循环伏安行为及有关电化学性质，制得了一种Ⅶｂ与ＴＣＮＱ反应生成的电荷转移络合物，讨论了噻吩基ＴＴＦ和呋喃基ＴＴＦ在产物构型和电化学性质方面的差别。     

湖北十堰绿松石中杂质矿物自然硒的谱学研究

近期在湖北绿松石市场上出现一种带有肉眼可见的灰黑色异形杂质的绿松石,于此种绿松石的研究甚少。故选取来自湖北省十堰的一块该种绿松石原石,蓝色绿松石基底上布满形态各异、大小不一的灰黑色杂质,放大观察可见灰黑色杂质矿物呈金属光泽。对灰黑色杂质采用激光剥蚀电感耦合等离子体质谱仪进行原位微区微量元素测试、背散射电子图像物相观察、主量化学成分测试采用能谱仪进行半定量测试和电子探针定量测试以及显微激光拉曼光谱仪测试。灰黑色杂质矿物的LA-ICP-MS测试激光剥蚀束斑直径及深度的影响,测试结果表现为灰黑色杂质矿物和少量绿松石的混合物的化学成分含量,灰黑色杂质矿物处Se含量为95 927～221 394 μg·g-1明显高于蓝色基底绿松石中Se的含量（146～212 μg·g-1）,灰黑色杂质处的测试结果中CuO含量为7.47%～9.28%、Al₂O₃含量为28.1%～35.7%,P₂O₅含量为30.1%～37.8%为少量绿松石混杂产生;背散射电子图像表明杂质矿物结晶颗粒细小,细小的杂质矿物与绿松石混杂在一起,他形的杂质矿物为多个晶体集合在一起形成的集合体,能谱测试结果表明杂质矿物主要含有Al,P,Fe,Cu和Se,电子探针主量化学成分定量测试结果表明杂质矿物主要含有Se,含量为79.34%～87.97%,此外,由于杂质矿物结晶颗粒细小,杂质矿物集合体中可见杂质矿物与绿松石混杂,因此化学成分定量测试结果中还呈现有绿松石中的Al,P,Fe,Cu和Al含量约为0.93%～4.13%,Cu含量约为1.30%～2.04%,P含量约为0.66%～2.40%,Fe含量约为0.31%;杂质矿物的显微激光拉曼光谱峰为位于144和235 cm-1处的尖锐拉曼谱峰,结合化学成分谱学测试结果可鉴别该杂质矿物主要为自然硒。硒矿物是绿松石中新发现的杂质矿物,绿松石中杂质矿物自然硒的发现可以为珠宝从业者鉴别绿松石提供有效的鉴定依据。     

Effect of laser intensity on fast-electron-beam divergence in solid-density plasmas

Metal foil targets were irradiated with 1 mum wavelength (lambda) laser pulses of 5 ps duration and focused intensities (I) of up to 4x10;{19} W cm;{-2}, giving values of both Ilambda;{2} and pulse duration comparable to those required for fast ignition inertial fusion. The divergence of the electrons accelerated into the target was determined from spatially resolved measurements of x-ray K_{alpha} emission and from transverse probing of the plasma formed on the back of the foils. Comparison of the divergence with other published data shows that it increases with Ilambda;{2} and is independent of pulse duration. Two-dimensional particle-in-cell simulations reproduce these results, indicating that it is a fundamental property of the laser-plasma interaction.     

Thermal Decomposition and Dehydration Kinetics of Tetra(piperidinium) Octamolybdate Tetrahydrate in Air

Thermal decomposition of tetra(piperidinium) octamolybdate tetrahydrate, [C₅H₁₀NH₂]₄[Mo₈O₂₆]·4H₂O, was investigated in air by means of TG‐DTG/DTA, DSC, TG‐IR and SEM. TG‐DTG/DTA curves showed that the decomposition proceeded through three well‐defined steps with DTA peaks closely corresponding to mass loss obtained. Kinetics analysis of its dehydration step was performed under non‐isothermal conditions. The dehydration activation energy was calculated through Friedman and Flynn‐Wall‐Ozawa (FWO) methods, and the best‐fit dehydration kinetic model function was estimated through the multiple linear regression method. The activation energy for the dehydration step of [C₅H₁₀NH₂]₄[Mo₈O₂₆]·4H₂O was 139.7 kJ/mol. The solid particles became smaller accompanied by the thermal decomposition of the title compound.     

Near QED regime of laser interaction with overdense plasmas

Interaction of laser plulses with intensities up to 10²⁵?W/cm² with overdense plasma targets is investigated via three-dimensional particle-in-cell simulations. At these intensities, radiation of electrons in the laser field becomes important. Electrons transfer a significant fraction of their energy to γ-photons and obtain strong feedbacks due to radiation reaction (RR) force. The RR effect on the distribution of laser energies among three main species: electrons, ions and photons is studied. The RR and electron-positron pair creation are implemented by a QED model. As the laser intensity inreases, the ratio of laser energy coupled to electrons drops while the one for γ-photons reaches up to 35%. Two distinctive plasma density regimes of the high-density carbon target and low-density solid hydrogen target are identified from the laser energy partitions and angular distributions of photons. The power-laws of absorption efficiency versus laser intensity and the transition of photon divergence are revealed. These show enhanced generation of γ-photon beams with improved collimation in the relativistically transparent regime. A new effect of transverse trapping of electrons inside the laser field caused by the RR force is observed: electrons can be unexpectedly confined by the intense laser field when the RR force is comparable to the Lorentz force. Finally, the RR effect and different regions of photon emission in laser-foil interactions are clarified.     

铜取代Dawson结构杂多钨磷酸电荷转移配合物的合成与性质研究

Two new charge-transfer complexes, (DMAH)₁₀［CuP₂W₁₇O₆₂］·DMF·2H₂O and (DMAH)₁₄［Cu₂P₂W₁₆O₆₂］ have been prepared in aqueous solution from N,N′-dimethylaniline(DMA) and copper substituted polyoxotungstates with Dawson Structure, and characterized by elemental analysis, ICP, TG, IR, diffusion reflectance electronic spectra, polarography, and CV. The results indicate that the structure of anion has little change after the charge-transfer complexes are formed, but the characteristic vibrational bands have some red shift or blue shift. The charge transfer takes place under sunlight. There is a new absorption band at 625 nm in the solid reflectance electronic spectra of the complexes, it is ascribed to the IVCT (W(V)→W(Ⅵ) band of the reduced anion ［CuP₂W₁₇O₆₂］^10-. The conductivities at room temperature of title complexes are 3.6×10^-9 S·cm^-1 and 5.4×10^-9 S·cm^-1, respectively. Both of them are weak semiconductors.     

超细均分散稀土化合物胶体粒子制备

利用尿素分解法制得轻、中、重稀土化合物的超细均分散胶体粒子,详细探讨了浓度、pH值、陈化温度、陈化时间及共存阴离子等因素对制备过程的影响,获得了各种粒子的最佳制备条件.     

Cyclodextrin knowledgebase a web-based service managing CD-ligand complexation data

Cyclodextrins are cyclic oligosaccharides that are able to form water-soluble inclusion complexes with small molecules. Because of their complexing ability, they are widely applied in food, pharmaceutical and chemical industries. In this paper we describe the development of a free web-service, Cyclodextrin KnowledgeBase: (http://www.cyclodextrin.net). The database contains four modules: the Publication, Interaction, Chirality and Analysis Modules. In the Publication Module, almost 50,000 publication details are collected that can be retrieved by text search. In the Interaction and Chirality Modules relevant literature data on cyclodextrin complexation and chiral recognition are collected that can be retrieved by both text and structural searches. Moreover, in the Analysis Module, the geometries of small molecule-cyclodextrin complexes can be predicted using molecular docking tools in order to explore the structures and interaction energies of the inclusion complexes. Complex geometry prediction is made possible by the built-in database of 95 cyclodextrin derivatives, where the 3D structures as well as the partial charges are calculated and stored for further utilization. The use of the database is demonstrated by several examples.     

Microcalorimetric Investigation of Influence of Fungicide SYP-L190 on Growth Metabolism of Tetrahyrnena therrnophila and Bacillus thuringiensis

Flumorph (SYP‐L190) is a new systemic fungicide with good protective, curative and antisporulant activities but no phytotoxicity to certain plants. Its performance on the environmental ecosystem is unknown. Tetrahymena thermophila and Bacillus thuringiensis are two of biological indicators for the aquatic and soil environmental ecosystem respectively. Microcalorimetric technique based on the heat output was applied to evaluate the influence of fungicide flumorph (SYP‐L190) on the two microorganisms. The thermogenic curves and corresponding thermodynamic and thermokinetic parameters were obtained. SYP‐L190 at a concentration of 50–100 µg·mL^?1 had 5% –10% inhibitory ratios aganist Tetrahymena thermophila and was used as a protection reagent, while at a concentration of 100–200 µg·mL^?1 SYP‐L190 had 10% –20% inhibitory ratios and was used as a therapy reagent. The metabolic thermogenic curves of Bacillus thuringiensis contained bacterial growth phase and sporulation phase. The SYP‐L190 at a concentration of 0–200 µg·mL^?1 had no influence on bacterial growth phase, but led to a little lag of the sporulation phase with a constant heat output. Hormesis was obviously observed in present study.