Preparation of Three Decadeoxyribonucleotides Containing an Uncommon or Modified Base

Three decadeoxyribonucleotides (d-C-C-A-A-I-A-T-T-G-G, d-C-^brC-A-A-G-A-T-T-G-G and d-C-C-A-A-^mG-A-T-T-G-G) involving inosine (I), 5-bromocytidine (^brC) and 6-O-methylguanosine (^mG) were chemically synthesized based on the phosphotriester approach in milligram quantities. The procedures of full protection reaction of these uncommon or modified bases are given in detail. The phosphotriester method was then employed to synthesize all the decamers. It seems the phosphotriester method is applicable to the synthesis of oligodeoxyribonucleotide with these three odd-bases. However, slightly different procedures have to be used while deblocking the fully protected oligodeoxyribonucleotides depending upon the nature of the uncommon or modified base.     

Total synthesis of kukoamine A,an antihypertensive constituent of lycium chinense

The active constituent of “jikoppi,” a clinically effective Oriental medicine for hypertension, has been synthesized from spermine using new methodology for polyamine alkylation.     

Optical focusing feature of single element in 128×128 elements electrically controllable cylindrical liquid crystal lens array

<正>A 128×128 elements cylindrical liquid crystal(LC) lens array with electrically controllable focal length is proposed.The cylindrical LC lens array uses transparent indium tin oxide(ITO) films as electrode,avoiding to affect the optical path operating in the voltage-off status.As the top electrode of the cylindrical LC lens array contacts with LC,the operation voltage root-mean-square(RMS) amplitude can be as low as 1.4 V and the response time is about 20-30 ms.The special optical focusing feature of the cylindrical LC lens array is got.And the focal length of this array is about 60-450μm.     

基于室温脉冲量子级联激光器的NO气体检测中的光谱处理方法研究

报导了采用基于室温脉冲量子级联激光器的脉内光谱检测技术,利用中心波长为1904 cm^-1的量子级联激光器,在实验室对NO气体样品进行检测的研究结果. 针对单线直接吸收光谱反演算法进行了研究,介绍了基线拟合的最小二乘算法以获取其吸光度,根据HITRAN数据库中相应吸收谱线的吸收线强,采用扫描积分实现了气体浓度的反演,避免了标气标定造成的误差及污染;通过拟合残差分析得到了系统的检测限,达到34×10^-6 m.     

Studies on oxidopyrylium [5+2] cycloadditions: toward a general synthetic route to the C12-hydroxydaphnetoxins

[Structure: see text] 12-hydroxydaphnetoxins, members of the structurally fascinating daphnane diterpene family, exhibit a wide range of significant biological activities. A general route to the BC-ring system of 12-hydroxy daphnetoxins is reported based on D-ribose. Depending on the choice of protecting groups and solvent, the oxidopyrylium-alkene [5+2] cycloaddition originating from A provides cycloadduct diastereomer B or C with good to excellent selectivity.     

Surface-enhanced Raman scattering from silver nanostructures with different morphologies

Scanning electron microscopy and X-ray diffraction reveal that four different types of crystalline silver nanostructures including nanoparticles, nanowires, nanocubes, and bipyramids are synthesized by a solvothermal method by reducing silver nitrate with ethylene glycol using poly(vinylpyrrolidone) as an adsorption agent and adding different quantities of sodium chloride to the solution. These nanostructures which exhibit different surface plasma resonance properties in the ultraviolet–visible region are shown to be good surface-enhanced Raman scattering (SERS) substrates using rhodamine 6G molecules. Our results demonstrate that the silver nanocubes, bipyramids with sharp corners and edges, and aggregated silver nanoparticles possess better SERS properties than the silver nanowires, indicating that they can serve as high-sensitivity substrates in SERS-based measurements.     

Bias dependence of apparent layer thickness and Moiré pattern on NaCl/Cu(001)

Bias-dependent features of the insulating NaCl layer grown on Cu(001) have been investigated by scanning tunneling microscopy/spectroscopy (STM/STS). The apparent layer thickness of the NaCl film is variable at bias voltages ranging from 2.8 to 3.2 V as well as from 4.0 to 5.0 V, and the Moiré pattern induced by NaCl–Cu lattice mismatch also shows bias dependence. The z–V (dz/dV–V) curves and dI/dV mapping measurements reveal that the resonant tunneling between the image potential states (IPSs) on Cu(001) and the Fermi level of the STM tip leads to drastic variations of these features.     

Linear Congruences in Continued Fractions on Finite Alphabets

Mathematical Notes - A linear homogeneous congruence ay ≡ bY (mod q) is considered and an order-sharp upper bound for the number of its solutions is proved. Here a, b, and q are given jointly...