Antioxidant and antimelanogenic activities of polyamine conjugates from corn bran and related hydroxycinnamic acids     

Choi SW  Lee SK  Kim EO  Oh JH  Yoon KS  Parris N  Hicks KB  Moreau RA 《Journal of agricultural and food chemistry》2007,55(10):3920-3925

The antioxidant activity of three major polyamine conjugates, N,N'-dicoumaroyl-putrescine (DCP), N-p-coumaroyl-N'-feruloylputrescine (CFP), and N,N'-diferuloyl-putrescine (DFP) isolated from corn bran, and their related hydroxycinnamic acids, p-coumaric acid and ferulic acid, were evaluated by three antioxidant in vitro assay systems, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide and hydroxyl radicals generated by enzymatic and nonenzymatic reactions. Additionally, five phenolic compounds were evaluated for melanogenesis inhibitory activity using mushroom tyrosinase and B16 melanoma cells. Most of the phenolic compounds significantly scavenged DPPH, superoxide, and hydroxyl radicals in a dose-dependent manner. Particularly, DFP showed potent DPPH (IC50 = 38.46 microM) and superoxide (IC50 = 291.62 microM) radical scavenging activities, while DCP exhibited the strongest hydroxyl radical scavenging activity (IC50 = 120.55 microM). CFP also exerted moderate DPPH, superoxide, and hydroxyl radical scavenging activities. Meanwhile, DCP (IC50 = 181.73 microM) showed potent tyrosinase inhibitory activity toward l-tyrosine as the substrate, whereas DFP (IC50 = 733.64 microM) significantly inhibited melanin synthesis in B16 melanoma cells. These current results indicate that these three polyamine conjugates from corn bran may be useful potential sources of natural antioxidants and skin-whitening agents.  相似文献   

Accounting for uncertainty in pedotransfer functions in vulnerability assessments of pesticide leaching to groundwater   总被引：1，自引：0，他引：1  

Stenemo F  Jarvis N 《Pest management science》2007,63(9):867-875

A simulation tool for site-specific vulnerability assessments of pesticide leaching to groundwater was developed, based on the pesticide fate and transport model MACRO, parameterized using pedotransfer functions and reasonable worst-case parameter values. The effects of uncertainty in the pedotransfer functions on simulation results were examined for 48 combinations of soils, pesticides and application timings, by sampling pedotransfer function regression errors and propagating them through the simulation model in a Monte Carlo analysis. An uncertainty factor, f(u), was derived, defined as the ratio between the concentration simulated with no errors, c(sim), and the 80th percentile concentration for the scenario. The pedotransfer function errors caused a large variation in simulation results, with f(u) ranging from 1.14 to 1440, with a median of 2.8. A non-linear relationship was found between f(u) and c(sim), which can be used to account for parameter uncertainty by correcting the simulated concentration, c(sim), to an estimated 80th percentile value. For fine-textured soils, the predictions were most sensitive to errors in the pedotransfer functions for two parameters regulating macropore flow (the saturated matrix hydraulic conductivity, K(b), and the effective diffusion pathlength, d) and two water retention function parameters (van Genuchten's N and alpha parameters). For coarse-textured soils, the model was also sensitive to errors in the exponent in the degradation water response function and the dispersivity, in addition to K(b), but showed little sensitivity to d. To reduce uncertainty in model predictions, improved pedotransfer functions for K(b), d, N and alpha would therefore be most useful.  相似文献   

Testing MACRO (version 5.1) for pesticide leaching in a Dutch clay soil   总被引：2，自引：0，他引：2  

Scorza Júnior RP  Jarvis NJ  Boesten JJ  van der Zee SE  Roulier S 《Pest management science》2007,63(10):1011-1025

Testing of pesticide leaching models against comprehensive field-scale measurements is necessary to increase confidence in their predictive ability when used as regulatory tools. Version 5.1 of the MACRO model was tested against measurements of water flow and the behaviour of bromide, bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide] and imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] in a cracked clay soil. In keeping with EU (FOCUS) procedures, the model was first calibrated against the measured moisture profiles and bromide concentrations in soil and in drain water. Uncalibrated pesticide simulations based on laboratory measurements of sorption and degradation were then compared with field data on the leaching of bentazone and imidacloprid. Calibrated parameter values indicated that a high degree of physical non-equilibrium (i.e. strong macropore flow) was necessary to describe solute transport in this soil. Comparison of measured and simulated bentazone concentration profiles revealed that the bulk of the bentazone movement in this soil was underestimated by MACRO. Nevertheless, the model simulated the dynamics of the bentazone breakthrough in drain water rather well and, in particular, accurately simulated the timing and the concentration level of the early bentazone breakthrough in drain water. The imidacloprid concentration profiles and its persistence in soil were simulated well. Moreover, the timing of the early imidacloprid breakthrough in the drain water was simulated well, although the simulated concentrations were about 2-3 times larger than measured. Deep groundwater concentrations for all substances were underestimated by MACRO, although it simulated concentrations in the shallow groundwater reasonably well. It is concluded that, in the context of ecotoxicological risk assessments for surface water, MACRO can give reasonably good simulations of pesticide concentrations in water draining from cracking clay soils, but that prior calibration against hydrologic and tracer data is desirable to reduce uncertainty and improve accuracy.  相似文献   

Witnessed Cardiac Arrest in a Hypothermic Avalanche Victim Completely Buried for 2 Hours     

Nicholas Daniel  Nicholas Weinberg  Frank Carus  Benjamin Church  Ken Zafren 《The Forestry Chronicle》2021,32(1):92-97

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PROGRESS ON IMPROVING AGRICULTURAL NITROGEN USE EFFICIENCY: UK-CHINA VIRTUAL JOINT CENTERS ON NITROGEN AGRONOM     

Tom MISSELBROOK  Zhaohai BAI  Zejiang CAI  Weidong CAO  Alison CARSWELL  Nicholas COWAN  Zhenling CUI  David CHADWICK  Bridget EMMETT  Keith GOULDING  Rui JIANG  Davey JONES  Xiaotang JU  Hongbin LIU  Yuelai LU  Lin MA  David POWLSON  Robert M. REES  Ute SKIBA  Pete SMITH  Roger SYLVESTER-BRADLEY  John WILLIAMS  Lianhai WU  Minggang XU  Wen XU  Fusuo ZHANG  Junling ZHANG  Jianbin ZHOU  Xuejun LIU 《农业科学与工程前沿(英文版)》2022,9(3):475

● Virtual joint centers on N agronomy were established between UK and China. ● Key themes were improving NUE for fertilizers, utilizing livestock manures, and soil health. ● Improved management practices and technologies were identified and assessed. ● Fertilizer emissions and improved manure management are key targets for mitigation. Two virtual joint centers for nitrogen agronomy were established between the UK and China to facilitate collaborative research aimed at improving nitrogen use efficiency (NUE) in agricultural production systems and reducing losses of reactive N to the environment. Major focus areas were improving fertilizer NUE, use of livestock manures, soil health, and policy development and knowledge exchange. Improvements to fertilizer NUE included attention to application rate in the context of yield potential and economic considerations and the potential of improved practices including enhanced efficiency fertilizers, plastic film mulching and cropping design. Improved utilization of livestock manures requires knowledge of the available nutrient content, appropriate manure processing technologies and integrated nutrient management practices. Soil carbon, acidification and biodiversity were considered as important aspects of soil health. Both centers identified a range of potential actions that could be taken to improve N management, and the research conducted has highlighted the importance of developing a systems-level approach to assessing improvement in the overall efficiency of N management and avoiding unintended secondary effects from individual interventions. Within this context, the management of fertilizer emissions and livestock manure at the farm and regional scales appear to be particularly important targets for mitigation.  相似文献   

Stereotactic Radiosurgery and Fracture Fixation in 6 Dogs With Appendicular Osteosarcoma     

Jennifer L. Covey DVM  Diplomate ACVS  James P. Farese DVM  Diplomate ACVS  Nicholas J. Bacon Vet MB  Diplomate ACVS & ECVS  Pierre Amsellem DVM  Diplomate ACVS  Ryan P. Cavanaugh DVM  Diplomate ACVS  Rowan J. Milner BVSc  MMed Vet  Diplomate ACVIM 《Veterinary surgery : VS》2014,43(2):174-181

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Use of the Thomas Splint and Cast Combination,Walker Splint,and Spica Bandage with an Over the Shoulder Splint for the Treatment of Fractures of the Upper Limbs in Cattle     

Aubrey Nicholas Baird  Stephen B. Adams  DVM  MS 《Veterinary Clinics of North America: Food Animal Practice》2014

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Active habitat selection by pre-settlement reef fishes   总被引：10，自引：0，他引：10  

John Charles Montgomery  Nicholas Tolimieri  & Olivia Sophie Haine 《Fish and Fisheries》2001,2(3):261-277

Our understanding of habitat selection by reef fish larvae has changed dramatically in the last 10 years. Fish larvae have long been considered passive particles at the mercy of ocean currents, tides and weather events. For reef fishes, ecological evidence has shown that passive dispersal alone often cannot explain larval distributions, suggesting active behaviour by reef fish larvae. While behaviourally modified passive transport may be important, recent work demonstrates that some reef fish larvae have the capability to actively swim to settlement habitat. They can orientate to reefs from distances of at least 1 km and can swim at speeds of 13.5 cm s^?1 for several days. The question then becomes, what are the cues that fish larvae use to orientate to reefs? Ambient reef sound has been shown to be attractive to reef fish larvae, and current research aims to understand better the nature and use of these acoustic cues. Other potential cues include chemoreception/olfaction, wave cues and visual location of reefs. A better understanding of active habitat selection and the underlying sensory and behavioural mechanisms will improve our knowledge of recruitment processes in reef fish ecology, and may have implications for active management of reef fish populations.  相似文献   

Methods of assessing extinction risk in marine fishes   总被引：1，自引：0，他引：1  

Nicholas K Dulvy  Jim R Ellis  Nicholas B Goodwin  Alastair Grant  John D Reynolds  & Simon Jennings 《Fish and Fisheries》2004,5(3):255-276

The decline and disappearance of species from large parts of their former geographical range has become an important issue in fisheries ecology. There is a need to identify which species are at risk of extinction. The available approaches have been subject to considerable debate – particularly when applied to commercially exploited species. Here we have compiled methods that have been used or may be used for assessing threat status of marine organisms. We organize the methods according to the availability of data on the natural history, ecology and population biology of species. There are three general approaches to inferring or assessing extinction risk: (i) correlative approaches based on knowledge of life histories and ecology; (ii) time‐series approaches that examine changes in abundance; and (iii) demographic approaches based on age‐ or stage‐based schedules of vital rates and fisheries reference points. Many methods are well suited to species that are highly catchable and/or have relatively low productivity, but theory is less well developed for assessing extinction risk in species exhibiting narrow geographical distributions or ecological specialization. There is considerable variation in both definitions of extinction risk and the precision and defensibility of the available risk assessment methods, so we suggest a two‐tiered approach for defining and assessing extinction risk. First, simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species. Second, the populations and species identified as vulnerable by this process can then be subject to more detailed and rigorous population analysis explicitly considering sources of error and uncertainty.  相似文献   

Nearshore fish assemblages associated with introduced predatory fishes in lakes     

Justin Trumpickas  Nicholas E. Mandrak  Anthony Ricciardi 《水产资源保护:海洋与淡水生态系统》2011,21(4):338-347