昆虫性信息素的研究 Ⅱ.顺-11-十六碳烯醛的合成

顺-11-十六碳烯醛(10)是鳞翅目昆虫信息素的主要组份之一,它的合成在文献上已有一些报道。本文则报道从顺-5-癸烯醇-1(3)     

Synthesis of (Z)-trisubstituted olefins with all substituents different from methylvia α,β-disubstituted (E)-acroleins

(E)-2,3-Disubstituted allyl bromides readily accessible in two steps from the corresponding enals react with dialkyl cuprates in a high regio- and stereoseiective fashion to give (Z)-trisubstituted olefins with all substituents different from methyl. This reaction was used in the synthesis of benzyl 7-methyl-3-propyldeca-(2Z,6Z)-dienyl ether, a derivative of a component of the sex pheromone of the lesser apple wormLaspeyresia pomonella L. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1381–1386, July, 1998.     

光学活性松干蚧性信息素C-8-C-13片断的合成

本文报道了从(S)-香茅醇合成化合物(2R)-3,5-dimethyl-hexan-1-o1(9), 即光学活性日本松干蚧性信息素C-8-C13片断, 共经九步反应, 总产率为57%。     

用毛细管色谱柱分离昆虫性信息素几何异构体的研究

本文叙述了七种毛细管柱对顺式和反式十二碳烯-1-醇及其乙酸酯(一系列不同双键位置的化合物)的分离效果,和这些化合物在色谱上的Kovats指数值。     

Protein quality of irradiated Brazilian beans

Beans are a major source of dietary protein in Brazil. However, high losses due to insect infestation occur after each harvest. To combat these losses, radiation processing of beans offers promise as an alternative to chemical treatment, provided the nutritional quality of beans is not impaired by the radiation treatment. Conflicting results have been published about the effect of radiation on the biological value of legume proteins. Therefore, two varieties of Brazilian beans were studied: 1) Phaseolus vulgaris L., var. carioca and 2) Vigna unguiculata (L.) Walp, var. macaçar. The beans were irradiated with doses of 0, 0.5, 1.0, 2.5, 5.0 and 10 kGy. Since irradiated beans will be consumed after appropriate storage, the beans under study were stored for 6 months at ambient temperature. Protein quality was measured by a biological assay employing the nitrogen balance approach in weanling rats. The animals were fed with optimally cooked beans, which were the only source of protein (10%). Nitrogen contents of legumes, diets, animal urine and faeces were determined by Kjeldahl analysis. The indices for apparent protein quality: net protein utilisation, digestibility and biological value were not influenced by irradiation. Thus, radiation treatment of Brazilian beans offers considerable promise as an effective insect disinfection process, without impairing the biological quality of the valuable bean protein.     

Insect Pheromones and Their Analogs. LXI. Synthesis of 4E,10Z-Tetradecadien-1-ylacetate, a Component of the Lithocolettis ringoniella Sex Pheromone

A new scheme for synthesizing 4E,10Z-tetradecadien-1-ylacetate, the principal component of the apple leaf miner(Lithocolettis ringoniella)sex pheromone, is developed using a highly stereoselective Claisen rearrangement     

基于光谱图像的森林病虫害自动检测方法

我国天然林区分布范围广,地形复杂,依靠传统的护林员巡检方式进行林木病虫害防治,效率较低,难于及时发现早期的林木病虫害,可能因此错过防治的最佳时机。针对该问题,设计了一种基于多光谱图像检测林木病虫害的深度学习网络,研发了一套检测软件,通过无人机挂飞实验,利用搭建的深度学习网络,完成林区染病区检测,对检测结果进行了分析。     

Structure and stereochemistry of products of hydroxylation of human steroid hormones by a housefly cytochrome P450 (CYP6A1)

The structure and stereochemistry of nine steroid metabolites isolated in quantities ranging from 0.15 to 1.8 mg were determined using a variety of NMR techniques, including heteronuclear multiple bond correlation (HMBC) using broadband adiabatic 13C pulses and phase-sensitive data presentation. Testosterone, androstenedione and progesterone were oxidized with housefly cytochrome P450 6A1 enzyme reconstituted in vitro with housefly NADPH cytochrome P450 reductase and cytochrome b5. NMR analysis in CD3OD using a modified HMBC sequence as well as 2D heteronuclear single quantum correlation (HSQC), COSY and nuclear Overhauser and exchange spectroscopy (NOESY), combined with a detailed analysis of J couplings showed that hydroxylation occurs exclusively on the beta-face of the steroids, at positions 2, 12, and 15.     

Global dynamics of a special class of nonlinear semelparous Leslie matrix models

ABSTRACT

This paper considers the dynamics of nonlinear semelparous Leslie matrix models. First, a class of semelparous Leslie matrix models is shown to be dynamically consistent with a certain system of Kolmogorov difference equations with cyclic symmetry. Then, the global dynamics of a special class of the latter is fully determined. Combining together, we obtain a special class of semelparous Leslie matrix models which possesses generically either a globally asymptotically stable positive equilibrium or a globally asymptotically stable cycle. The result shows that the periodic behaviour observed in periodical insects can occur as a globally stable phenomenon.