The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Andrew D. M. Hart - One of the best experts on this subject based on the ideXlab platform.
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Effects of food restriction on food avoidance and risk of acute poisoning of captive feral pigeons from Fonofos-treated seeds
Archives of environmental contamination and toxicology, 1999Co-Authors: Juan A. Pascual, S. L. Fryday, Andrew D. M. HartAbstract:Fonofos is a highly toxic insecticide to birds that, when used as a cereal seed treatment, has caused mortality of free-living feral pigeons (Columba livia). Pigeons kept individually under ad libitum feeding conditions in the laboratory do not suffer lethal poisoning because they develop a strong avoidance response to Fonofos-treated seed, which restricts consumption to below lethal levels. Two laboratory experiments were conducted to assess the role of avoidance in reducing the risk of acute poisoning of captive birds under food stress. In the first experiment, pigeons acclimatized to feed on untreated wheat seeds for 6 h/day were presented with Fonofos-treated seeds for 6 h on a testing day, following normal food surplus in one experimental group (eight birds) and 6 days of deprivation in another (eight birds). In the second experiment, different pigeons were acclimatized to a feeding regime of 2 h/day and treated seeds were offered without previous restriction (eight birds) or after 6 days of food restriction in which birds were given 15% of normal intake (eight birds). In the second experiment, six birds in each experimental group were videotaped to study their feeding behavior. Survivors at the end of the testing day were killed, and all birds were dissected and analyzed to determine carcass and pectoral muscle composition. Food-stressed birds lost ∼11% of their initial body weight during 6 days of total or partial food restriction, but they still had visible fat deposits and a high body fat content, indicating that they were in good body condition in terms of energy reserves. Consumption of treated seeds on the testing day was reduced in comparison with normal intake of untreated seed in all birds, but there were differences between experimental groups. In ad libitum–fed birds, consumption of treated seed in each experiment averaged 12% and 19% of normal levels, exposure to Fonofos was below lethal levels, and no bird died. In food-stressed birds, consumption was higher (34% or 56% of normal levels for the first and second experiments, respectively) and led to the ingestion of seed containing lethal doses of pesticide. Two birds in the first experiment and three in the second died of acute poisoning within around 2 h of initial exposure. The avoidance response developed quickly in both ad libitum–fed and food-stressed birds. Feeding took place in most birds almost exclusively in the first 9 min of the testing day. Within this interval, birds of the two experimental groups stopped ingesting treated seeds around 6 min after the onset of feeding. The differences between experimental groups in consumption of treated seed were due to the higher feeding rate and effective feeding time in food-stressed birds. It is concluded that although feral pigeons under severe food stress develop an early and strong conditioned food aversion to Fonofos-treated seeds, avoidance does not always prevent mortality. The need for including hunger stress as a factor in avian dietary toxicity tests to make testing conditions more representative of those experienced by wild birds is discussed.
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exposure of captive feral pigeons to Fonofos treated seed in a semifield experiment
Environmental Toxicology and Chemistry, 1997Co-Authors: Juan A. Pascual, Andrew D. M. HartAbstract:This study aimed to investigate factors affecting risks to birds from toxic seed treatments under typical field use. Fetal pigeons (Columba livia) were exposed for 2 d to Fonofos-treated wheat seeds by holding them in pens in plots sown at two depths following standard husbandry in winter sowings in English fenland. In the shallow plots, seeds were readily available to pigeons on the soil surface (8.20 seeds/0.25 m 2 ) while in the deep plots little seed was left uncovered (0.20 seeds/0.25 m 2 ). Serum butyrylcholinesterase analysis revealed negligible exposure to Fonofos of birds from deep plots but significant exposure of those in shallow plots. Data on body weight and the availability of exposed seed showed that pigeons in the shallow plots stopped eating treated seeds without depleting those exposed on the soil even though the seed consumed was less than 26% of birds' daily food requirements. Neither mortality nor signs of poisoning were observed. Though seeds were treated at the approved rate (1,080 mg a.i./kg seed), Fonofos concentration in seeds from the hopper (586.5 mg/kg) and from plots during testing (260.2 and 201.7 mg/kg for days +1 and +2 after sowing, respectively) was substantially lower. In this experiment, the avoidance of Fonofos-treated seeds together with the low concentration of Fonofos in seeds prevented pigeons from ingesting a lethal dose. In the wild, however, pigeons are poisoned occasionally by Fonofos, and it has yet to be determined under what conditions this occurs.
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Exposure of captive feral pigeons to Fonofos‐treated seed in a semifield experiment
Environmental Toxicology and Chemistry, 1997Co-Authors: Juan A. Pascual, Andrew D. M. HartAbstract:This study aimed to investigate factors affecting risks to birds from toxic seed treatments under typical field use. Fetal pigeons (Columba livia) were exposed for 2 d to Fonofos-treated wheat seeds by holding them in pens in plots sown at two depths following standard husbandry in winter sowings in English fenland. In the shallow plots, seeds were readily available to pigeons on the soil surface (8.20 seeds/0.25 m 2 ) while in the deep plots little seed was left uncovered (0.20 seeds/0.25 m 2 ). Serum butyrylcholinesterase analysis revealed negligible exposure to Fonofos of birds from deep plots but significant exposure of those in shallow plots. Data on body weight and the availability of exposed seed showed that pigeons in the shallow plots stopped eating treated seeds without depleting those exposed on the soil even though the seed consumed was less than 26% of birds' daily food requirements. Neither mortality nor signs of poisoning were observed. Though seeds were treated at the approved rate (1,080 mg a.i./kg seed), Fonofos concentration in seeds from the hopper (586.5 mg/kg) and from plots during testing (260.2 and 201.7 mg/kg for days +1 and +2 after sowing, respectively) was substantially lower. In this experiment, the avoidance of Fonofos-treated seeds together with the low concentration of Fonofos in seeds prevented pigeons from ingesting a lethal dose. In the wild, however, pigeons are poisoned occasionally by Fonofos, and it has yet to be determined under what conditions this occurs.
Zhiyun Zhang - One of the best experts on this subject based on the ideXlab platform.
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Combining Headspace Solid-Phase Microextraction and Surface-Enhanced Raman Spectroscopy To Detect the Pesticide Fonofos in Apple Juice.
Journal of food protection, 2018Co-Authors: Haoxin Chen, Chunrong Wang, Zhiyun ZhangAbstract:ABSTRACT We developed an innovative approach that couples headspace solid-phase microextraction (SPME) with surface-enhanced Raman spectroscopy (SERS) to detect a volatile pesticide (i.e., Fonofos) in a liquid complex matrix (i.e., apple juice). A gold nanoparticles–coated fiber was fabricated by reducing gold(III) on a chemically etched stainless steel wire to extract pesticide, using SPME. The fabricated fibers were then tested by a headspace-SPME method and a dip-SPME method, followed by SERS detection of Fonofos in water and apple juice samples. Using the headspace-SPME method, we can detect as low as 5 ppb of Fonofos in water and apple juice, compared with the dip-SPME method, which cannot detect lower than 10 ppb in water and 50 ppb in apple juice. This study demonstrated the potential capability of the headspace-SPME-SERS method for rapid (within 30 min) and sensitive detection of volatile and vaporizable compounds in complex matrices. The developed method could be a potential alternative approach ...
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A facile solvent mediated self-assembly silver nanoparticle mirror substrate for quantitatively improved surface enhanced Raman scattering.
The Analyst, 2017Co-Authors: Chen Tan, Zhiyun ZhangAbstract:Herein, a facile solvent mediated silver nanoparticle (AgNP) mirror was introduced as a reproducible and sensitive surface-enhanced Raman scattering (SERS) substrate. The AgNP mirror was fabricated based on commercially available citrate coated AgNPs via a facile and unique water-solvent interface assembly method without using any electrical equipment. By adding 0.2 mg ml-1 citrate coated AgNPs dropwise into a mediating solvent, self-assembled AgNP mirrors were formed instantly and gradually settled down at the bottom. The mediating solvent is the key for this fabrication, which should contain a mixture of a non-polar (e.g. hexane, cyclohexane, and iso-octane) and a polar (e.g., acetonitrile, acetone, methanol, and ethanol) organic solvents that have a lower density than water. The fabricated AgNP mirror showed a uniform monolayer arrangement which produced highly reproducible and sensitive signals. The coefficient of variance (i.e., percentage relative standard deviation) for AgNP mirrors was 7.3% compared to 33.0% for AgNP aggregates. A lower limit of detection (0.008 ppm) and a higher coefficient of determination (0.9981) for the detection of the Fonofos pesticide were also obtained from the AgNP mirror compared to that from the AgNP aggregates. The practical application of this nanoscale AgNP mirror sensing substrate was also confirmed by its accurate quantification of 0.5 ppm Fonofos in apple juice and green tea (i.e., 105.06% and 106.16% recovery value, respectively).
Juan A. Pascual - One of the best experts on this subject based on the ideXlab platform.
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Effects of food restriction on food avoidance and risk of acute poisoning of captive feral pigeons from Fonofos-treated seeds
Archives of environmental contamination and toxicology, 1999Co-Authors: Juan A. Pascual, S. L. Fryday, Andrew D. M. HartAbstract:Fonofos is a highly toxic insecticide to birds that, when used as a cereal seed treatment, has caused mortality of free-living feral pigeons (Columba livia). Pigeons kept individually under ad libitum feeding conditions in the laboratory do not suffer lethal poisoning because they develop a strong avoidance response to Fonofos-treated seed, which restricts consumption to below lethal levels. Two laboratory experiments were conducted to assess the role of avoidance in reducing the risk of acute poisoning of captive birds under food stress. In the first experiment, pigeons acclimatized to feed on untreated wheat seeds for 6 h/day were presented with Fonofos-treated seeds for 6 h on a testing day, following normal food surplus in one experimental group (eight birds) and 6 days of deprivation in another (eight birds). In the second experiment, different pigeons were acclimatized to a feeding regime of 2 h/day and treated seeds were offered without previous restriction (eight birds) or after 6 days of food restriction in which birds were given 15% of normal intake (eight birds). In the second experiment, six birds in each experimental group were videotaped to study their feeding behavior. Survivors at the end of the testing day were killed, and all birds were dissected and analyzed to determine carcass and pectoral muscle composition. Food-stressed birds lost ∼11% of their initial body weight during 6 days of total or partial food restriction, but they still had visible fat deposits and a high body fat content, indicating that they were in good body condition in terms of energy reserves. Consumption of treated seeds on the testing day was reduced in comparison with normal intake of untreated seed in all birds, but there were differences between experimental groups. In ad libitum–fed birds, consumption of treated seed in each experiment averaged 12% and 19% of normal levels, exposure to Fonofos was below lethal levels, and no bird died. In food-stressed birds, consumption was higher (34% or 56% of normal levels for the first and second experiments, respectively) and led to the ingestion of seed containing lethal doses of pesticide. Two birds in the first experiment and three in the second died of acute poisoning within around 2 h of initial exposure. The avoidance response developed quickly in both ad libitum–fed and food-stressed birds. Feeding took place in most birds almost exclusively in the first 9 min of the testing day. Within this interval, birds of the two experimental groups stopped ingesting treated seeds around 6 min after the onset of feeding. The differences between experimental groups in consumption of treated seed were due to the higher feeding rate and effective feeding time in food-stressed birds. It is concluded that although feral pigeons under severe food stress develop an early and strong conditioned food aversion to Fonofos-treated seeds, avoidance does not always prevent mortality. The need for including hunger stress as a factor in avian dietary toxicity tests to make testing conditions more representative of those experienced by wild birds is discussed.
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exposure of captive feral pigeons to Fonofos treated seed in a semifield experiment
Environmental Toxicology and Chemistry, 1997Co-Authors: Juan A. Pascual, Andrew D. M. HartAbstract:This study aimed to investigate factors affecting risks to birds from toxic seed treatments under typical field use. Fetal pigeons (Columba livia) were exposed for 2 d to Fonofos-treated wheat seeds by holding them in pens in plots sown at two depths following standard husbandry in winter sowings in English fenland. In the shallow plots, seeds were readily available to pigeons on the soil surface (8.20 seeds/0.25 m 2 ) while in the deep plots little seed was left uncovered (0.20 seeds/0.25 m 2 ). Serum butyrylcholinesterase analysis revealed negligible exposure to Fonofos of birds from deep plots but significant exposure of those in shallow plots. Data on body weight and the availability of exposed seed showed that pigeons in the shallow plots stopped eating treated seeds without depleting those exposed on the soil even though the seed consumed was less than 26% of birds' daily food requirements. Neither mortality nor signs of poisoning were observed. Though seeds were treated at the approved rate (1,080 mg a.i./kg seed), Fonofos concentration in seeds from the hopper (586.5 mg/kg) and from plots during testing (260.2 and 201.7 mg/kg for days +1 and +2 after sowing, respectively) was substantially lower. In this experiment, the avoidance of Fonofos-treated seeds together with the low concentration of Fonofos in seeds prevented pigeons from ingesting a lethal dose. In the wild, however, pigeons are poisoned occasionally by Fonofos, and it has yet to be determined under what conditions this occurs.
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Exposure of captive feral pigeons to Fonofos‐treated seed in a semifield experiment
Environmental Toxicology and Chemistry, 1997Co-Authors: Juan A. Pascual, Andrew D. M. HartAbstract:This study aimed to investigate factors affecting risks to birds from toxic seed treatments under typical field use. Fetal pigeons (Columba livia) were exposed for 2 d to Fonofos-treated wheat seeds by holding them in pens in plots sown at two depths following standard husbandry in winter sowings in English fenland. In the shallow plots, seeds were readily available to pigeons on the soil surface (8.20 seeds/0.25 m 2 ) while in the deep plots little seed was left uncovered (0.20 seeds/0.25 m 2 ). Serum butyrylcholinesterase analysis revealed negligible exposure to Fonofos of birds from deep plots but significant exposure of those in shallow plots. Data on body weight and the availability of exposed seed showed that pigeons in the shallow plots stopped eating treated seeds without depleting those exposed on the soil even though the seed consumed was less than 26% of birds' daily food requirements. Neither mortality nor signs of poisoning were observed. Though seeds were treated at the approved rate (1,080 mg a.i./kg seed), Fonofos concentration in seeds from the hopper (586.5 mg/kg) and from plots during testing (260.2 and 201.7 mg/kg for days +1 and +2 after sowing, respectively) was substantially lower. In this experiment, the avoidance of Fonofos-treated seeds together with the low concentration of Fonofos in seeds prevented pigeons from ingesting a lethal dose. In the wild, however, pigeons are poisoned occasionally by Fonofos, and it has yet to be determined under what conditions this occurs.
Donald Mcnaughton - One of the best experts on this subject based on the ideXlab platform.
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Surface-enhanced Raman spectroscopic analysis of Fonofos pesticide adsorbed on silver and gold nanoparticles
Journal of Raman Spectroscopy, 2010Co-Authors: Jitraporn Vongsvivut, Evan G. Robertson, Donald McnaughtonAbstract:Surface-enhanced Raman scattering (SERS) spectra of Fonofos, an organophosphorous pesticide (OPP), were recorded using citrate-reducedsilver(Ag)andgold(Au)colloidalnanoparticlesintheformofdriedfilms.Inthisstudy,significantenhancements wereachievedwithFonofosconcentrationsdownto ∼10 ppmwiththeAgcolloids,demonstratingapotentialforthetechnique in the analysis of Fonofos residues. Successful formation of the SERS-active metal aggregates was indicated by the presence of a plasmon band at longer wavelengths in the UV‐visible spectrum. Transmission electron microscopy (TEM) images revealed distinctively different morphologies of the aggregates formed by the two metals, while the observed SERS spectral features of Fonofos were also found to be different for molecules adsorbed on Ag and Au colloidal surfaces. This evidence suggests metal-induced changes in adsorption behavior of the Fonofos analyte, leading to the different binding structures onto the different metal surfaces. Comparisons between the most prominent SERS-enhanced bands and the precise mode descriptions predictedthroughdensityfunctionaltheory(DFT)simulationsattheB3LYP/6-311+G(d,p)levelallowedanin-depthorientation analysisoftheadsorbedspeciesonmetalsurfaces.Nevertheless,theringvibrationswerefoundtopossessamajorcontribution in the observed SERS enhancementsfor both metal nanoparticles. Copyright c � 2010 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this article.
S. D. Miller - One of the best experts on this subject based on the ideXlab platform.
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Insecticide placement interactions with preplant herbicides in sugarbeets
Journal of Sugarbeet Research, 1995Co-Authors: K. J. Fornstrom, S. D. MillerAbstract:Pesticides are required to obtain an adequate stand of weed-free sugarbeets, but they often cause sugarbeet injury and/or stand loss. The objective of this research was to evaluate the interactive effects of insecticides, insecticide placement, and preplant herbicides on sugarbeet stand establishment and injury. No interactions or insecticide effects were found in three experiments when insecticides and preplant herbicides were band-applied and rotary incorporated ahead of the sugarbeet planter. Severe injury (25 percent) and stand reductions (76 percent) resulted with Fonofos applied prior to the planter press wheel with all herbicide treatments, as compared to applying Fonofos prior to the rotary incorporator or behind the planter press wheel. Results from a study at four locations with three insecticide placements, four insecticide treatments and four herbicide treatments indicated an insecticide placement x herbicide interaction for sugarbeet injury, but the differences were small. The largest sugarbeet population differences were due to preplant herbicide treatment. It appears that if insecticides are incorporated ahead of the planter or behind the planter press wheel, there was not much additional sugarbeet stand loss or injury than from preplant herbicides applied alone.