自由基正离子引发的多取代四氢呋喃类化合物的合成

五元氧杂环是非常重要的合成目标化合物.它们大量存在于天然产物中[1],大多具有生物活性[2],而且也是应用广泛的有机中间体[3].因此,有关此类化合物的合成方法学研究一直为人们所重视.文献中大多采用[3原子+2原子]的方式来构建此类杂环,近年来,自由基或过渡金属成为诱导此类反应的强有力的工具[4].     

CYTOPLASMIC EFFECT ON GENE FUNCTION IN Xenopus laevis

The pigmentation gene of Xenopus laevis is dominant and that of albino a~p mutant recessive. Hete-rologous haploid hybrids are produced by UV inactivation of the egg nuclei during second polar body for-mation in the mutant sperm-fertilized Xenopus eggs. During development of these hybrids, melanin ap-peared in the eye and melanophores in the skin at stages comparable to those of the wild type, but muchearlier than in the albino mutant. The number and intensity of pigment cells are interinediate betweenthe black Xenopus and albino mutant. While a number of pigment cells remain in the hybrids, thosein the albino eventually degenerate. Therefore, the development and maintenance of pigmentation in hete-rologous hybrids are contributed by Xenopus cytoplasm. Tadpole tail-tips were squashed and stained for chromosome counting. The results show thatXenopus and mutants are diploid (36 chromosomes) and heterologous haploid hybrids have 18 chromosomes.     

Detection of Tumor Necrosis Factor Gene by Piezoelectric Nucleic Acid Senosr

A piezoelectric nucleic acid sensor was constructed ofr detection of tumor necrosis factor gene.Two methods were employed for immobilization of nucleic acid probe on gold electrode of piezoelectric crystal.The results show that polyethyleneimine adbesion and glutaraldehyde cross-linking method has higher sensitivity,stability and selectivity than protein A method.The solid-phase nucleic acid hybridization of oligo unclecotides and tumor necrosis factor target gene sequence were monitorde using this sensor.Tumor necrosis factor gene sequence(580bp) was detected by this nucleic acid sensor for the first time.     

Dislocation Analysis for Large-sized Sapphire Single Crystal Grown by SAPMAC Method

In this paper,large-sized sapphire (230×210 mm,27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at the cooled center). Dislocation peculiarity in large sapphire boule (0001) basal plane was investigated by chemical etching,scanning electron microscopy and X-ray topography method. The triangular dislocation etch pit measured is 7.6×101～8.0×102 cm-2,in which relative high-density dislocations were generated at both initial and final stages of crystal growth. The analysis of single-crystal X-ray topography shows that there are no apparent sub-grain boundaries; the dislocation lines are isolated and straight. Finally,the origins of low-density dislocation in sapphire crystal are discussed by numerical analysis method.     

痤疮患者血清中微量元素含量的变化

测定了52例痤疮患者血清Ca,Mg,Zn,Cu,Fe五种元素的含量。结果表明，痤疮患者血清Zn水平显著低于正常人（P＜0．001），血清Ca,Mg,Cu,Fe水平则与正常人无差别（P＞0．05）。部分病人口服补充锌剂后痤疮症状有所好转。提示痤疮患者应重视体内微量元素含量的变化，并做适当的补充。     

Detection of Tumor Necrosis Factor Gene by Piezoelectric Nucleic Acid Sensor

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甲烷氧化偶联W-Mn/SiO2催化剂上O2-脉冲频率效应(PFE)的研究

采用频率脉冲反应方法,以Mn-Na2WO4/S iO2催化剂上甲烷氧化偶联为探针反应,通过实时、原位的四极质谱检测手段,研究氧物种对甲烷C-H键选择性活化的微观历程.首次发现了Mn-Na2WO4/S iO2催化剂上O2-脉冲频率效应,即脉冲反应产物量随氧脉冲注入频率的增加而增加.研究结果表明,在反应条件下,Mn-Na2WO4/S iO2催化剂上有两种活化甲烷的氧物种同时存在,它们活化甲烷的方式不同。     

Chemical Constituents of Ailanthus triphysa

Two new compounds,8(14),15-isopimaradiene-2α，３α，19-triol(1),and 6α，７β－dihydroxy-17(20)-cis-5α－pregna-16-one(2),together with four known copounds,a oxygenated rare phyllocladane,phyllocladan-16α，19-diol(3),kaempferol-3-0-β－Ｄ-galactopyranosied,kaempferol-3-0-α－Ｌ－rhamnopyranoside and scopoletin, were isolated from the leaves of Ailanthus tripysa.Structures of 1-3 were elucidated on the basis of spectroscopic data as compared with related compounds.     

流动注射分光光度法测定水体总磷

提出了一种单通道紫外消解流动注射比色分析法，能快速测定水样中总磷。实验采用了微量恒流混合泵、新型的细长型高灵敏度流通池及紫外消解器、液流分配阀、恒流瓶等FIA装置，并使用工业编程控制器和智能触摸屏进行控制和计算，使操作更为方便。此法分析时间短，测量范围宽，精度高，适合于各种水体的测定。     

A MATHEMATICAL STUDY OF THE SEVEN GRAPTOLITE BIOZONES OF THE LOWER SILURIAN LONGMAXIAN STAGE IN CHINA

With the aid of matrix theory and computer a series of data can be obtained such as the total number of localities in which r species of graptolites appears, the common number of localities in which both i and j species of graptolites appear, the total number of species of graptolites in one locality, the common number of species of graptolites found in both i and j localities, the total number of zones in which r species of graptolites appears, the common number of zones in which both i and j species appear, the total number of species of graptolites found in one zone, the common number of species of graptolites found in both i and j zones. Based on these data a common problem in biostratigraphy may be solved, that is, in the absence of the zonal graptolite which species of graptolites can be chosen to replace the zonal graptolite, or how to detect the zonal graptolite of a graptolite biozone. The result of matrix treatment not only detects the graptolite biozone but is useful to infer the paleo-biogeo