No abstract

Two (2-hydroxypropyl) trimethyl ammonium and/or imidazole-based quaternary ammonium chitosan derivatives (NHT-chitosan and Im-OHT-chitosan) were synthesized by using nucleophilic substitution reaction. These two synthesized chitosan derivatives were characterized by Fourier transform infrared spectroscopy, NMR spectra, and UV-visible spectra. The applications as antioxidant agents and cathepsin D inhibitors were further investigated. Both of quaternary ammonium chitosan derivatives exhibited good antioxidant activity upon scavenging against hydroxyl radical and hydrogen peroxide as well as the lipid peroxidation inhibition in the linoleic acid emulsion system. They also exhibited good inhibition activity of cathepsin D protease. NHT-chitosan and Im-OHT-chitosan are potential the natural, healthy and safe preservatives in food industry.

Relationship between space image and tourists' path selection patterns plays a very important role in landscape planning and design in scenic areas. Based on research of West Lake scenic area in Hang Zhou, this article studies the small scale space scenic images and big scale spatial structure images through questionnaire surveys, image recognition, image sketch, factor analysis, dynamic observation and other methods. The results indicate that there are four main types of space activities among the West Lake tourists, namely (1) the general activity type in the Bai Causeway and Su Causeway, (2) the general activity type in the Sunset Glow at Leifeng Pagoda, (3) the surrounding activity type in the Evening Bell at Nanping Hill, and (4) the surrounding activity type in the Music Fountain Square; and the proportion score has it in order from high to low. The score results of tourists' identifying picture and frequency of the five elements of space image in image maps are consistent with four main types of space activities observed by dynamic lines. Therefore, tourists' perception results of space image can directly affect the route choice behavior. And the more image elements can be perceived, the more reasonable path choices can be made. Finally, the research puts forward some suggestions tentatively on the planning and design of the West Lake area.