The chemical constituents from red alga Gymnogongrus flabelliformis Harv.

Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and 1D NMR spectroscopic data, their structures were determined as: stigmast-4-en-3-one (I), cholest-4-en-3-one (II), cholesterol (III), uracil (IV), uridine (V), adenosine (VI), succinic acid (VII), and 5-hydroxy-4-methyl-5-pentyl-2,5-dihydro-furan-2-on (VIII). All of them were obtained from this species for the first time. Cytotoxicity of these compounds was screened using standard MTT method, but all the compounds were inactive (IC50 > 10 mu g/ml).

品牌表现评价反应时与关注特性的关系

The decision making of customers has been a great concern in the field of customer research. Although China has entered the era of brand consumption and development, due to the different understanding of the regarded attributes between companies and customers, the phenomenon of “The awarded products don’t sell well, but the products which sell well can’t get the award.” appears. At the same time there is little research on the relationship between the brand and the customers has been conducted in China now. Traditional research on customer psychology employ questionnaires, depth interview and group discussions as the major methods. In cognitive psychology, the limitation of explicit memory has been revealed by implicit memory; moreover, unconscious cognition and implicit memory can also influence customers' remark of the brand. Therefore, the traditional methods are not accurate enough. Reaction time is an effective way to reveal testing equality, and it can also reveal implicit cognition. Based on the researches intends to investigate the validity of attention attributes in the method of reaction time by questionnaires and time reaction testing of 360 customers in 3 cities, which may, probably, overcomes the limitation of the traditional research methods. The 352 valid samples were analyzed by SPSS. The results showed there was no distinct corresponding relationship between the product attributes and reaction time. The different key attributes from questionnaire importance rating and the shortest reaction time standards were used to regressively analyze the results of customers’ overall rating (such as overall satisfaction,objective quality, recommend intention).The results indicated that the coefficiency of regression of the special attributes chosen from reaction time to overall rating was distinct, while the coefficiency of the special attributes chosen from importance rating to overall rating was not. The main conclusions are: 1. Regarded attributes can be obtained by the reaction time of brand performance rating. 2. Regarded attributes obtained by the reaction time of brand performance rating are more accurate than those by importance rating questionnaires. 3. The brand’s core attributes should includes regarded attributes during the decision making process.

Titanium species in titanium silicalite TS-1 prepared by hydrothermal method

The titanium species existing in titanium silicalite TS-1, which is prepared by hydrothermal method, were investigated using chemical analysis, XRD, FT-IR, Si-29 MAS NMR, UV-VIS, ESR. It has been observed that several kinds of titanium species may exist in titanium silicalite. The form that titanium atoms incorporate into the framework of titanium silicalite synthesized using tetrapropylammonium bromide (TPABr) as template differs from that using the classical method. But, the symmetry of titanium silicalite, changes from monoclinic to orthorhombic with the increase of titanium content in both methods. The Ti-O-2(-) originated from framework titanium and H2O2 has the moderate stability and may be active site in oxidation reaction. TS-1 synthesized using TPABr as template does not contain anatase, but contains a kind of partly condensed titanium species with six-fold coordination. The titanium species may correspond to 270-280 mn band in UV-VIS spectra and also can form Ti-O-2(-). But, this kind of Ti-O-2(-) is very stable and cannot be catalytic active site. So, the six-fold coordination titanium species may be inactive in both the oxidation reaction and the decomposition of H2O2. The hypothesis has been further proved by the phenomena that the titanium species is easily washed off using acid, and acid treating will not influence the catalytic performance of TS-1. (C) 2001 Elsevier Science B.V. All rights reserved.