Determination of total amitraz residue in honey by electron capture capillary gas chroma tography–a simplified method     

Maria Barbina Taccheo  Mauro De Paoli  Claudio Spessotto 《Pest management science》1988,23(1):59-64

A gas chromatographic method using a capillary column is described for the determination of total amitraz residue in honey samples. The method consists of a preliminary extraction of the sample, an alkaline hydrolysis, an extraction of the 2, 4-dimethylaniline formed, without the aid of steam distillation/continuous extraction, its derivatisation with heptafluorobutyric anhydride and a gas chromatographic determination using an electron capture detector. The method is very rapid and can be carried out in a test tube. The detection limit is 0.020 mg kg^?1 and recoveries are of the order of 85%.  相似文献   

Uptake and metabolism as mechanisms of selective herbicidal activity of the 1,2,4-triazolo[1,5-a] pyrimidines     

Craig C. Hodges  Gerrit J. De Boer  Javier Avalos 《Pest management science》1990,29(3):365-378

In order to identify the factors providing the triazolopyrimidines with a wide range of selectivity amongst agriculturally important plant species, studies were made on the uptake and metabolism of a representative compound, N-(2,6-dichlorophenyl)-5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine- 2-sulfonamide. This compound is much more phytotoxic to dicots than to monocots. Experiments showed that variations in leaf morphologies and geometries relative to spray applications resulted in different herbicide dosages applied to plant species used in selectivity evaluations. However, this parameter did not have a statistically significant correlation to herbicide selectivity measurements. Characterization of the metabolic pathways showed that the major herbicide metabolites involved methyl hydroxylation or hydroxylation of the aniline ring followed by glucose conjugation. Since these metabolites were not exclusive to either monocots or dicots, herbicide selectivity does not appear dependent on the pathway of metabolism. Studies on the kinetics of metabolism suggest instead that metabolic rate was important. Monocots metabolized the herbicide rapidly and generally were tolerant while the opposite was true of dicots.  相似文献   

Modelling the escape of Chondrostereum purpureum spores from a larch forest with biological control of Prunus serotina     

Meindert D. De Jong  Patricia S. Wagenmakers  J. Goudriaan 《European journal of plant pathology / European Foundation for Plant Pathology》1991,97(1):55-61

Chondrostereum purpureum is being developed as a microbial herbicide to controlPrunus serotina in coniferous forests. After biological control, the fungus produces basidiospores that may reach and infect non-target plants. As part of a risk analysis, spore escape from a forest was quantified. For this purpose, a stratified model was developed for a forest of 250 m with 250 m. A turbulent diffusion equation was used to describe spore fluxes for each layer.In a simple calculation procedure, the spore fluxes for the different layers were calculated simultaneously. The downwind escape fraction was found to vary from 0.19 to 0.45, and the upward escapte fraction from 0.07 to 0.23. These escape fractions increased with increasing wind speed.Number of spores released from basidiocarps, and escape fractions could be used as inputs for a Gaussian plume model to calculate spore immission into orchards.  相似文献   

Comparative purification methods for determination of triadimenol residues in plant material     

Patricia V. Reynaud  Sylvaine D. Rolle  Louis De Cormis 《Pest management science》1991,32(1):121-131

Two procedures are described for the determination of residues of triadimenol and compared on cereal material. After extraction, purification is carried out by Florisil column chromatography in method I and by semi-preparative High-Performance Liquid Chromatography in method II. Triadimenol residues are quantified by gas chromatography with a thermoionic detector. With method I, interference was observed but not with method II. This specific procedure has been tested on other plant materials. Recoveries in the range of 90–98% indicate that this procedure is suitable for residue analysis of this fungicide with detection limits of 0·008 mg kg^?1 in wheat grains, 0·03 mg kg^?1 in wheat straw and 0·004–0·008 mg kg^?1 in other plants. Maximum residue limits in France are: 0·1 mg kg^?1 in grain, 2·0 mg kg^?1 in straw and 1·0 mg kg^?1 in other vegetables and fruit.  相似文献   

Contaminant and formulation analysis of MSMA using high-pressure liquid chromatography — graphite furnace atomic absorption spectrophotometry     

Frans E. Pick  Pieter R. De Beer  Susan M. Prinsloo  Louis P. Van Dyk 《Pest management science》1987,21(1):45-49

High-pressure liquid chromatography with an ion-exchange column combined with graphite furnace atomic absorption spectrometry was used to analyse commercial formulations of sodium hydrogen methylarsonate (MSMA). No arsenite or arsenate salts or dimethylarsinic acid were detected as contaminants in the formulations, and the MSMA concentrations were found to be in accordance with the concentrations given on the containers.  相似文献   

Development of a functional scoring system in dogs with acute spinal cord injuries     

Olby NJ  De Risio L  Muñana KR  Wosar MA  Skeen TM  Sharp NJ  Keene BW 《American journal of veterinary research》2001,62(10):1624-1628

OBJECTIVES: To develop and compare the reliability of 2 methods of scoring pelvic limb gait in dogs recovering from thoracolumbar spinal cord injuries and to use this scoring system to determine the rate and level of functional recovery of dogs with acute thoracolumbar intervertebral disk herniations. ANIMALS: 46 dogs with spinal cord injuries resulting from intervertebral disk herniations. PROCEDURE: Dogs' gaits were videotaped at different time intervals after injury. In phase 1 of the study, the stages of recovery of pelvic limb function were identified, and a numeric scoring system was devised to reflect that recovery. In phase 2, pelvic limb gait was scored by different observers, using a numeric and a visual analog scale. Intra- and interobserver coefficients of variability of both methods were compared. In phase 3, pelvic limb function was scored, using the numeric scale at various intervals after acute thoracolumbar disk herniations. RESULTS: The numeric scale was significantly more reliable than the visual analog scale when both intra- and interobserver coefficients of variability were evaluated. Dogs that were paraplegic with no deep pain sensation recovered at different rates during the first 3 months, whereas dogs that were paraplegic with deep pain sensation typically recovered within 1 month of injury. CONCLUSIONS: Pelvic limb gait of dogs recovering from thoracolumbar spinal cord injuries can be reliably quantified, using a numeric scale. This scale will facilitate the performance of clinical trials aimed at improving the outcome of acute spinal cord injuries.  相似文献   

Infectious bronchitis serology in broilers and broiler breeders: correlations between antibody titers and performance in vaccinated flocks     

De Herdt P  Ducatelle AR  Uyttebroek AE  Sneep A  Torbeyns R 《Avian diseases》2001,45(3):612-619

In this study, a follow-up was made between 1993 and 1997 from broiler breeders at birth down to offspring broilers at processing, through vertically integrated registration of infectious bronchitis virus (IBV) antibody titers and performance data. All measurements were used two by two in a simple correlation study to calculate the degree to which they were linearly correlated. The antibody patterns in the broiler breeders indicated frequent field infections breaking through vaccinal immunity. Significant correlations measured between antibody titers and production parameters within and between the generations strongly suggested negative effects of IBV infections on laying percentage in the breeders and on mortality and daily weight gain in the broilers. Economic losses associated with IBV infections in the broilers occurred predominantly in flocks hatched with low and erratic maternal antibody titers. We concluded that IBV vaccination strategies should aim at high and uniform antibody titers in the broiler breeders.  相似文献   

Epidemiology and significance of chicken infectious anemia virus infections in broilers and broiler parents under nonvaccinated European circumstances   总被引：3，自引：0，他引：3  

De Herdt P  Van den Bosch G  Ducatelle R  Uyttebroek E  Schrier C 《Avian diseases》2001,45(3):706-708

A serologic survey in unvaccinated broiler parent and broiler progeny flocks demonstrated seroconversion against chicken infecrious anemia virus (CIAV) in all parent flocks before or around point of lay and in 38% of the broiler flocks examined at slaughter age. The presence of CIAV antibodies at slaughter of broilers was positively correlated with slaughterhouse condemnation rates. Results indicate that CIAV infections are highly prevalent in both broiler parent and broiler flocks and that CIAV infections in broilers are associated with increased slaughterhouse condemnation.  相似文献   

Pharmacokinetics and bioavailability of sulfadiazine and trimethoprim (trimazin 30%) after oral administration in non-fasted young pigs     

Baert K  De Baere S  Croubels S  Gasthuys F  De Backer P 《Journal of veterinary pharmacology and therapeutics》2001,24(4):295-298

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Hepatozoon canis infection associated with dog ticks of rural areas of Rio de Janeiro State, Brazil     

O'Dwyer LH  Massard CL  Pereira de Souza JC 《Veterinary parasitology》2001,94(3):143-150

Hepatozoon canis is a tick-borne protozoan that infects dogs and has been reported throughout the world. Manifestation of H. canis infection varies from being sub-clinical in apparently healthy dogs to severe illness. The main vector of the infection is the dog tick, Rhipicephalus sanguineus although other species may also transmit this agent. H. canis has been reported previously in Brazil, but mostly as an occasional finding during laboratory exams and always associated with other diseases. The prevalence of H. canis in dogs of rural areas of Brazil has been little studied. For this study, 250 dogs from seven counties of Rio de Janeiro state were examined. All the dogs were from rural areas, near forest. Of the dogs examined, 26 dogs were from Seropédica, 82 from Itaguaí, 41 from Paracambi, 26 from Mangaratiba, 32 from Barra do Piraí, 32 from Piraí and 11 from Miguel Pereira. Blood smears from the peripheral blood of the ear were taken and ticks found on the dogs were collected for identification in the laboratory. Using blood smear evaluation, H. canis was identified in 39.2% of the animals examined. Other hemoparasites identified were Babesia canis (5.2%) and Ehrlichia canis (4.8%). Four tick species were found parasitizing the dogs: Amblyomma cajennense (23.6%), R. sanguineus (12.4%), Amblyomma aureolatum (2.8%) and Amblyomma ovale (2.0%). There was a positive correlation between the presence of A. cajennense and H. canis infection.  相似文献