An optimization model is proposed to analyze the optimal review revelation policies and consumer online social network management strategies of e-commerce firms.The results show that displaying friend reviews to consu...An optimization model is proposed to analyze the optimal review revelation policies and consumer online social network management strategies of e-commerce firms.The results show that displaying friend reviews to consumers does not necessarily increase firms profits.Only when positive reviews account for a large proportion of all the reviews and when the cost of showing friend reviews is not high,can showing friend reviews be more profitable than not showing such information.The distribution of social ties among consumers can affect firms profits.Even in the case that showing friend reviews to consumers is more profitable,an increase in the proportion of strong ties is not necessarily beneficial to firms.Only when the proportion of positive reviews is large enough,can firms profits increase with the increase in the proportion of strong ties among consumers.Moreover,the degree of consumer distrust in the average quality rating can also affect firms strategies for managing consumer online social networks.As the degree of consumer distrust in the average quality rating rises,firms are more likely to obtain higher profits by taking measures to increase the proportion of strong ties among consumers on their websites.展开更多
Echinops latifolius Tausch(ELT)is the traditional Mongolian medicine for the treatment of osteoporosis,and the ambiguous composition of active ingredients is an important factor in restricting the modernization and gl...Echinops latifolius Tausch(ELT)is the traditional Mongolian medicine for the treatment of osteoporosis,and the ambiguous composition of active ingredients is an important factor in restricting the modernization and globalization of this herb.Considering the traditional activity screening strategy is time-consuming and labor intensive,online HPLC active ingredient detection coupled with ESI-IT-TOF-MS^(n) strategy was employed in this study to isolate,identify and screen active compounds from the herbal medicines at the same time.The structure-activity relationship of these compounds was elucidated as well.Owing to the association of osteoporosis progression and oxidative stress,the antioxidants screening from ELT could be a good interpretive of the active substance in this herb.Meanwhile,DPPH equivalent method was an indicative of the most powerful antioxidant in ELT.Consequently,the screening and identification of the antioxidants in ELT was performed by using on-line HPLC-radical scavenging detection coupled with ESI-IT-TOF-MS^(n) strategy,and the structure-activity relationship was investigated based on DPPH equivalent method.Finally,20 constituents(including apigenin glucosides,caffeic acid,biscaffeoylquinic acids,biscaffeoylquinic acid methyl esters,ect.)were characterized in ELT extracts,and 18 components showed appreciable radical scavenging capacity.In addition,the structure-activity relationship study was carried out based on 14 compounds isolated from our laboratory,and the structural requirements of the compounds on antioxidant activity were obtained:(1)compounds with phenolic hydroxyl groups could have antioxidant activity;(2)the antioxidant activity could not be facilitated by the number of hydroxyl groups,but affected by the number of caffeoyl groups;(3)the substitution position of caffeoyl on quinic acid had a greater influence on DPPH activity;(4)methoxy groups could reduce the antioxidant activity.Collectively,this work provided the biochemical perspective to link active compounds and anti-osteoporosis action of ELT,and further explained how ELT worked in osteoporosis patients with bone loss.展开更多
基金The National Social Science Foundation of China(No.17BGL196).
文摘An optimization model is proposed to analyze the optimal review revelation policies and consumer online social network management strategies of e-commerce firms.The results show that displaying friend reviews to consumers does not necessarily increase firms profits.Only when positive reviews account for a large proportion of all the reviews and when the cost of showing friend reviews is not high,can showing friend reviews be more profitable than not showing such information.The distribution of social ties among consumers can affect firms profits.Even in the case that showing friend reviews to consumers is more profitable,an increase in the proportion of strong ties is not necessarily beneficial to firms.Only when the proportion of positive reviews is large enough,can firms profits increase with the increase in the proportion of strong ties among consumers.Moreover,the degree of consumer distrust in the average quality rating can also affect firms strategies for managing consumer online social networks.As the degree of consumer distrust in the average quality rating rises,firms are more likely to obtain higher profits by taking measures to increase the proportion of strong ties among consumers on their websites.
基金National Natural Science Foundation of China(Grant No.81860756,81960758)Natural Science Foundation of Inner Mongolia Autonomous Region(Grant No.2017MS08122,2019MS08111 and 2019MS08119)+2 种基金Inner Mongolia Science and Technology Innovation Guide Project(Grant No.02039001)Rolling Support Plan for Grassland Talents Project in Inner Mongolia Autonomous RegionInner Mongolia Autonomous Region Higher Education Science Research Project(Grant No.NJZY19099)。
文摘Echinops latifolius Tausch(ELT)is the traditional Mongolian medicine for the treatment of osteoporosis,and the ambiguous composition of active ingredients is an important factor in restricting the modernization and globalization of this herb.Considering the traditional activity screening strategy is time-consuming and labor intensive,online HPLC active ingredient detection coupled with ESI-IT-TOF-MS^(n) strategy was employed in this study to isolate,identify and screen active compounds from the herbal medicines at the same time.The structure-activity relationship of these compounds was elucidated as well.Owing to the association of osteoporosis progression and oxidative stress,the antioxidants screening from ELT could be a good interpretive of the active substance in this herb.Meanwhile,DPPH equivalent method was an indicative of the most powerful antioxidant in ELT.Consequently,the screening and identification of the antioxidants in ELT was performed by using on-line HPLC-radical scavenging detection coupled with ESI-IT-TOF-MS^(n) strategy,and the structure-activity relationship was investigated based on DPPH equivalent method.Finally,20 constituents(including apigenin glucosides,caffeic acid,biscaffeoylquinic acids,biscaffeoylquinic acid methyl esters,ect.)were characterized in ELT extracts,and 18 components showed appreciable radical scavenging capacity.In addition,the structure-activity relationship study was carried out based on 14 compounds isolated from our laboratory,and the structural requirements of the compounds on antioxidant activity were obtained:(1)compounds with phenolic hydroxyl groups could have antioxidant activity;(2)the antioxidant activity could not be facilitated by the number of hydroxyl groups,but affected by the number of caffeoyl groups;(3)the substitution position of caffeoyl on quinic acid had a greater influence on DPPH activity;(4)methoxy groups could reduce the antioxidant activity.Collectively,this work provided the biochemical perspective to link active compounds and anti-osteoporosis action of ELT,and further explained how ELT worked in osteoporosis patients with bone loss.
