诱导作用及其对复合调剖剂延缓胶凝的作用机理研究

介绍了诱导作用的基本概念及其存在与否的判断模式 .复合调剖剂由水解聚丙烯酰胺 (HPAM)、木质素磺酸钙 (Ca -LS)、重铬酸钠、硫脲等药剂共同组成 ,具有成胶时间可调 (5～ 30h)、凝胶强度高 [(10～ 40 )× 10 4 mPa·s]等特点 ,在某油田使用后经济效益显著 ,投入产出比为 1∶6 .33.室内对比评价实验结果表明 ,单独以重铬酸钠/木钙或重铬酸钠 /硫脲氧化还原体系为交联剂时 ,调剖剂存在交联过速或交联过缓以及凝胶强度过低的问题 ,均无法满足调剖剂成胶性能的要求 ;而以重铬酸钠 /木钙 /硫脲复合体系为交联剂时 ,调剖剂成胶时间可调、凝胶强度较高 ,满足性能要求 .通过实验判断模式及机理判断模式两种判断模式分析 ,均证实诱导作用是复合调剖剂起延缓成胶作用的关键     

Progress on Detection of Metals Ions by Functional Nucleic Acids Biosensor

Functional nucleic acids are natural or artificial nucleic acid sequences with specific functions and special structures. A part of metal ions are essential trace elements of human health, but excessive metal ions will be harmful to human health. The functional nucleic acids are widely used for detection of metal ions because of its advantages such as easy modification, low price, high stability and strong specificity. This paper detailed the interaction between functional nucleic acids and metal ions, mainly including cutting type, link type, metal ion-mediated base pairing, click chemistry type, conformational change type, and other types. The biosensors based on the combination of functional nucleic acid with different signal output were then introduced. Finally, the research significance and existing problems of functional nucleic acid for metal ion detection were discussed. The future development trends and applications of functional nucleic acid biosensor were prospected.     

N-alkylation of 2,3-dihydroimidazo[2,1-b]quinazolin-1(10)H-5-one. On the cryptoanionic mechanism of N-substitution

Quantum chemical methods involving studies of transition states of the reaction showed that the main products of N-alkylation of prototropic 2,3-dihydroimidazo[2,1-b]quinazolin-1(10)H-5-one (1) in the gas phase and under neutral conditions in solution occurring via the S_N2 mechanism should be N(10)-alkyl-substituted derivatives formed from the 1H-tautomer. Minor N(1)-substituted derivatives in solution can be produced from both tautomers. For the alkylation of the free N-anion of compound 1, position 1 is attacked first. Validity of conclusions concerning the overall regioselectivity of the reaction was confirmed experimentally. In the absence of solvent, the alkylation proceeds abnormally with a sharp increase in the content of the 1-substituted isomers up to inversion of the regioselectivity of the reaction, which is explained by the participation in the process of the H-bonded dimer of the substrate (1a)₂, which undergoes alkylation via the cryptoanionic mechanism. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 876–887, May, 2006.     

4-Hydroxy-2-quinolones 144. Alkyl-, arylalkyl-, and arylamides of 2-hydroxy-4-oxo-4H-pyrido[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine-3-carboxylic acid and their diuretic properties

Alkyl-, arylalkyl-, and arylamides of 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acid were prepared with a view to establishing a structure-biological activity relationship. A comparative analysis has been made of their diuretic properties and those of the structurally similar 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxamides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 718–729, May, 2008.     

Structural and biological behaviors of some nonionic Schiff-base amphiphiles and their Cu(II) and Fe(III) metal complexes

Novel series of nonionic Schiff bases was synthesized and characterized using microelemental analysis, FTIR and (1)H NMR spectra. These Schiff bases and their complexes with Cu and Fe have been evaluated for their antibacterial activity against bacterial species such as Staphylococcus aureus, Pseudomonas aureus, Candida albi, Bacillus subtilis and Escherichia coli and their fungicidal activity against Aspcrgillus niger and Aspcrgillus flavus. The results of the biocidal activities showed high potent action of the synthesized Schiff bases towards both bacteria and fungi. Furthermore, complexation of these Schiff bases by Cu(II) and Fe(III) show the metal complexes to be more antibacterial and antifungal than the Schiff bases. The results were correlated to the surface activity and the transition metal type. The mode of action of these complexes was discussed.     

Repeatability analysis of the Tetrahymena pyriformis population growth impairment assay

Assessments necessary to ensure the safety of both humans and the environment are challenged by the sheer number of chemicals in use today. Chemical legislation, such as REACH, aims to use alternative methods to reduce the reliance on in vivo animal testing. Consequently, databases such as the TETRATOX database, containing data from the Tetrahymena pyriformis population growth impairment assay, have been used extensively to develop computational models which aid in priority setting and initial hazard assessments. To use any toxicological data, an assessment of quality is required. One important aspect of quality is the repeatability of the assay. This study considered TETRATOX assay data for 85 structurally and mechanistically diverse compounds. The repeatability of replicate determinations was assessed and factors relating to repeatability are discussed. Despite the majority of compounds demonstrating excellent repeatability, it was found that the mechanism of action is likely to be a modulating factor, with compounds acting via electrophilic mechanisms being more likely to exhibit reduced repeatability than those acting via narcotic mechanisms. It is evident from this study that the TETRATOX assay is a robust and highly repeatable assay, suitable for use in toxicological modelling studies and priority setting.