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排序方式: 共有545条查询结果,搜索用时 15 毫秒
541.
Heather Troxell Aldrich Karen Salandanan Patricia Kendall Marisa Bunning Frank Stonaker Oktay Külen Cecil Stushnoff 《Journal of the science of food and agriculture》2010,90(15):2548-2555
BACKGROUND: Tomatoes (Solanum lycopersicum L.) are widely consumed and well known for their health benefits, many of which have been associated with the high levels of antioxidants present in tomatoes. With a growing interest in local and organic foods, it would be helpful to determine whether farmers could naturally improve the quality and antioxidant content of tomatoes for sale in local markets. This study evaluated antioxidant properties, quality attributes, and yield for 10 tomato cultivars grown for 2 years using certified organic and conventional practices. RESULTS: Cultivar and year effects impacted (P < 0.05) all tests conducted, while growing method influenced (P < 0.05) yield, soluble solids content, ascorbic acid, and antioxidant radical scavenging capacity. Even when accounting for year‐to‐year variability, cultivars in the highest groups had 1.35‐ to 1.67‐fold higher antioxidant levels than cultivars in the lowest groups. ‘New Girl’, ‘Jet Star’, ‘Fantastic’, and ‘First Lady’ were always in the highest groups, while ‘Roma’ and ‘Early Girl’ consistently had the lowest antioxidant content. CONCLUSION: Compared to production practices and environmental effects of years that are generally beyond the control of small‐scale producers, choice of cultivar provides the simplest and most effective means of increasing antioxidant properties. Knowledge of tomato cultivars with naturally higher antioxidant levels could assist smaller‐scale producers to grow fruit that may provide a competitive advantage and the opportunity to capitalize on the increasing popularity of locally grown, high‐quality fresh produce. Copyright © 2010 Society of Chemical Industry 相似文献
542.
Red tide detection and tracing using MODIS fluorescence data: A regional example in SW Florida coastal waters 总被引:3,自引:0,他引:3
Chuanmin Hu Frank E. Muller-Karger Kendall L. Carder Elizabeth Johns 《Remote sensing of environment》2005,97(3):311-321
Near real-time data from the MODIS satellite sensor was used to detect and trace a harmful algal bloom (HAB), or red tide, in SW Florida coastal waters from October to December 2004. MODIS fluorescence line height (FLH in W m− 2 μm− 1 sr− 1) data showed the highest correlation with near-concurrent in situ chlorophyll-a concentration (Chl in mg m− 3). For Chl ranging between 0.4 to 4 mg m− 3 the ratio between MODIS FLH and in situ Chl is about 0.1 W m− 2 μm− 1 sr− 1 per mg m− 3 chlorophyll (Chl = 1.255 (FLH × 10)0.86, r = 0.92, n = 77). In contrast, the band-ratio chlorophyll product of either MODIS or SeaWiFS in this complex coastal environment provided false information. Errors in the satellite Chl data can be both negative and positive (3-15 times higher than in situ Chl) and these data are often inconsistent either spatially or temporally, due to interferences of other water constituents. The red tide that formed from November to December 2004 off SW Florida was revealed by MODIS FLH imagery, and was confirmed by field sampling to contain medium (104 to 105 cells L− 1) to high (> 105 cells L− 1) concentrations of the toxic dinoflagellate Karenia brevis. The FLH imagery also showed that the bloom started in mid-October south of Charlotte Harbor, and that it developed and moved to the south and southwest in the subsequent weeks. Despite some artifacts in the data and uncertainty caused by factors such as unknown fluorescence efficiency, our results show that the MODIS FLH data provide an unprecedented tool for research and managers to study and monitor algal blooms in coastal environments. 相似文献
543.
544.
Dr. Simanga R. Gama Toda Stankovic Kendall Hupp Dr. Ahmed Al Hejami Mimi McClean Alysa Evans Prof. Dr. Diane Beauchemin Prof. Dr. Friedrich Hammerschmidt Dr. Katharina Pallitsch Prof. Dr. David L. Zechel 《Chembiochem : a European journal of chemical biology》2022,23(2):e202100352
The fungal metabolite Fosfonochlorin features a chloroacetyl moiety that is unusual within known phosphonate natural product biochemistry. Putative biosynthetic genes encoding Fosfonochlorin in Fusarium and Talaromyces spp. were investigated through reactions of encoded enzymes with synthetic substrates and isotope labelling studies. We show that the early biosynthetic steps for Fosfonochlorin involve the reduction of phosphonoacetaldehyde to form 2-hydroxyethylphosphonic acid, followed by oxidative intramolecular cyclization of the resulting alcohol to form (S)-epoxyethylphosphonic acid. The latter reaction is catalyzed by FfnD, a rare example of a non-heme iron/2-(oxo)glutarate dependent oxacyclase. In contrast, FfnD behaves as a more typical oxygenase with ethylphosphonic acid, producing (S)-1-hydroxyethylphosphonic acid. FfnD thus represents a new example of a ferryl generating enzyme that can suppress the typical oxygen rebound reaction that follows abstraction of a substrate hydrogen by a ferryl oxygen, thereby directing the substrate radical towards a fate other than hydroxylation. 相似文献
545.
Keri K. Stephens Courtney J. Powers Brett W. Robertson Lauryn A. Spearing John C. Collier Kendall P. Tich William R. Smith 《突发事故与危机管理杂志》2023,31(1):26-38
When a wildfire strikes, it impacts entire communities. Yet it can be challenging to get communities to take the lead in becoming more prepared, and thus build lasting resilience. Guided by theoretical preparedness models, and using a case study design, this study examines the planning, execution, and subsequent sensemaking around one of the first community-led wildfire evacuation drills in the United States. Findings illustrate the interplay between individual preparedness, communication, and community involvement as the neighbourhood studied conducted their drill in partnership with multiple emergency response organizations. Our model explains 39% of the variance in individuals' preparedness, finding that people with higher self-efficacy, more involved with the community, and who felt strong social norms around preparedness had more items prepared for a wildfire. The community's desire to share the preparedness organizing process with external audiences is a unique and important contribution in understanding how communication can be used to sustain community resilience. 相似文献