Abstract Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin present in many foods, posing a serious human health problem. Oriental high-salt fermented foods are highly susceptible to AFB1 contamination due to their production process and condition. Therefore, it is necessary to isolate microbial resources that can remove AFB1 in a high-salt condition. In the current study, forty-nine salt-tolerant microorganisms with the ability to remove AFB1 were isolated from Doubanjiang, a Chinese typical high-salt red pepper paste. Among them, Bacillus velezensis AD8 had the highest removal rate of AFB1. The AFB1 removal activity of B. velezensis AD8 was mainly attributed to culture supernatant, and it was sensitive to sodium dodecyl sulfate (SDS) or/and proteinase-K treatment, which indicated that extracellular enzyme contributed to the degradation of AFB1. The optimal incubation time, pH value and NaCl concentration of the initial medium for degradation of AFB1 by the B. velezensis AD8 were investigated. In addition, the AFB1 concentration had no significant effect on degradation activity. The addition of nitrogen source, Mg2+ and Mn2+ stimulated degradation rate, whereas addition of carbon source, Zn2+ and Fe2+ inhibited degradation. Thus, B. velezensis AD8 might be a potential candidate to degrade AFB1 in high-salt food matrices.

Abstract: Push-Pull-Mooring framework is adopted to identify the antecedents affecting users’ switching intention from Internet payment to mobile payment. Using the data obtained from 264 valid respondents, the results show that both the mooring factors (perceived switching cost and personal innovativeness) and pull factors (relative advantages of substitute information technology and critical mass) are direct antecedents affecting customer switching behavior. In addition, mooring factors could moderate the relationship between push factors (dissatisfaction on system quality and dissatisfaction on service quality) as well as pull factors and customer switching intention. Managerial implications of findings were provided to payment service providers for maintaining incumbent customers and attracting potential customers.

Abstract Vegetation coverage is an important indicator in regional ecological environment monitoring and plays a key role in its quality assessment. We consider Landsat7 ETM+ in 2000 and Landsat8 in 2016 as data sources using a different time phase partial image substitution method to eliminate cloud effects and an NDVI dimidiate pixel model to invert the vegetation coverage of the two time phases. We further classify them into five grades, provide statistics and analyse the areas of different grades at different time periods, while monitoring the spatial evolution of vegetation coverage over the past 16 years in Tongren. Experimental results showed that: (1) the different time phase partial image substitution method could reduce the influence of clouds on vegetation extraction; (2) in Tongren, the vegetation coverage area was decreased from 17,300.1 km2 to 17,224.8 km2 (i.e. decreased by 75.3 km2); (3) the areas of grade I and V increased by 0.42% and 15.08%, respectively, whereas the areas of grade II, III and IV decreased by 3.15%, 6.98% and 5.37%, respectively, which indicates that most of the area containing lower amount of vegetation gradually altered into an area containing a higher coverage of vegetation, whereas a few areas became bare land; and (4) the vegetation areas decreased due to expansion of cities and construction of dams, while vegetation increased due to the cultivation of crops and trees. Research shows that the overall evolution of vegetation coverage in Tongren is considerably good. However, while undertaking future development in the mountainous Karst region, one should be aware of the land’s intensive use and environmental protection.