The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Ala E Lew - One of the best experts on this subject based on the ideXlab platform.
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improved detection of tritrichomonas foetus in bovine diagnostic specimens using a novel probe based real time pcr assay
Veterinary Parasitology, 2006Co-Authors: Lyle Mcmillen, Ala E LewAbstract:A Tritrichomonas foetus-specific 5′ Taq nuclease assay using a 3′ minor groove binder-DNA probe (TaqMan® MGB) targeting conserved regions of the internal transcribed spacer-1 (ITS-1) was developed and compared to established diagnostic procedures. Specificity of the assay was evaluated using bovine venereal microflora and a range of related trichomonad species. Assay sensitivity was evaluated with log10 dilutions of known numbers of cells, and compared to that for microscopy following culture (InPouch™ TF test kit) and the conventional TFR3-TFR4 PCR assay. The 5′ Taq nuclease assay detected a single cell per assay from Smegma or mucus which was 2500-fold or 250-fold more sensitive than microscopy following selective culture from Smegma or mucus respectively, and 500-fold more sensitive than culture followed by conventional PCR assay. The sensitivity of the conventional PCR assay was comparable to the 5′ Taq nuclease assay when testing purified DNA extracted from clinical specimens, whereas the 5′ Taq nuclease assay sensitivity improved using crude cell lysates, which were not suitable as template for the conventional PCR assay. Urine was evaluated as a diagnostic specimen providing improved and equivalent levels of T. foetus detection in spiked urine by both microscopy following culture and direct 5′ Taq nuclease detection, respectively, compared with Smegma and mucus, however inconclusive results were obtained with urine samples from the field study. Diagnostic specimens (n = 159) were collected from herds with culture positive animals and of the 14 animals positive by 5′ Taq nuclease assay, 3 were confirmed by selective culture/microscopy detection (Fisher's exact test P < 0.001). The 5′ Taq nuclease assay described here demonstrated superior sensitivity to traditional culture/microscopy and offers advantages over the application of conventional PCR for the detection of T. foetus in clinical samples.
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comparison of culture and a novel 5 taq nuclease assay for direct detection of campylobacter fetus subsp venerealis in clinical specimens from cattle
Journal of Clinical Microbiology, 2006Co-Authors: Lyle Mcmillen, G Fordyce, V J Doogan, Ala E LewAbstract:A Campylobacter fetus subsp. venerealis-specific 5′ Taq nuclease PCR assay using a 3′ minor groove binder-DNA probe (TaqMan MGB) was developed based on a subspecies-specific fragment of unknown identity (S. Hum, K. Quinn, J. Brunner, and S. L. On, Aust. Vet. J. 75:827-831, 1997). The assay specifically detected four C. fetus subsp. venerealis strains with no observed cross-reaction with C. fetus subsp. fetus-related Campylobacter species or other bovine venereal microflora. The 5′ Taq nuclease assay detected approximately one single cell compared to 100 and 10 cells in the conventional PCR assay and 2,500 and 25,000 cells from selective culture from inoculated Smegma and mucus, respectively. The respective detection limits following the enrichments from Smegma and mucus were 5,000 and 50 cells/inoculum for the conventional PCR compared to 500 and 50 cells/inoculum for the 5′ Taq nuclease assay. Field sampling confirmed the sensitivity and the specificity of the 5′ Taq nuclease assay by detecting an additional 40 bulls that were not detected by culture. Urine-inoculated samples demonstrated comparable detection of C. fetus subsp. venerealis by both culture and the 5′ Taq nuclease assay; however, urine was found to be less effective than Smegma for bull sampling. Three infected bulls were tested repetitively to compare sampling tools, and the bull rasper proved to be the most suitable, as evidenced by the improved ease of specimen collection and the consistent detection of higher levels of C. fetus subsp. venerealis. The 5′ Taq nuclease assay demonstrates a statistically significant association with culture (χ2 = 29.8; P < 0.001) and significant improvements for the detection of C. fetus subsp. venerealis-infected animals from crude clinical extracts following prolonged transport.
Lyle Mcmillen - One of the best experts on this subject based on the ideXlab platform.
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improved detection of tritrichomonas foetus in bovine diagnostic specimens using a novel probe based real time pcr assay
Veterinary Parasitology, 2006Co-Authors: Lyle Mcmillen, Ala E LewAbstract:A Tritrichomonas foetus-specific 5′ Taq nuclease assay using a 3′ minor groove binder-DNA probe (TaqMan® MGB) targeting conserved regions of the internal transcribed spacer-1 (ITS-1) was developed and compared to established diagnostic procedures. Specificity of the assay was evaluated using bovine venereal microflora and a range of related trichomonad species. Assay sensitivity was evaluated with log10 dilutions of known numbers of cells, and compared to that for microscopy following culture (InPouch™ TF test kit) and the conventional TFR3-TFR4 PCR assay. The 5′ Taq nuclease assay detected a single cell per assay from Smegma or mucus which was 2500-fold or 250-fold more sensitive than microscopy following selective culture from Smegma or mucus respectively, and 500-fold more sensitive than culture followed by conventional PCR assay. The sensitivity of the conventional PCR assay was comparable to the 5′ Taq nuclease assay when testing purified DNA extracted from clinical specimens, whereas the 5′ Taq nuclease assay sensitivity improved using crude cell lysates, which were not suitable as template for the conventional PCR assay. Urine was evaluated as a diagnostic specimen providing improved and equivalent levels of T. foetus detection in spiked urine by both microscopy following culture and direct 5′ Taq nuclease detection, respectively, compared with Smegma and mucus, however inconclusive results were obtained with urine samples from the field study. Diagnostic specimens (n = 159) were collected from herds with culture positive animals and of the 14 animals positive by 5′ Taq nuclease assay, 3 were confirmed by selective culture/microscopy detection (Fisher's exact test P < 0.001). The 5′ Taq nuclease assay described here demonstrated superior sensitivity to traditional culture/microscopy and offers advantages over the application of conventional PCR for the detection of T. foetus in clinical samples.
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comparison of culture and a novel 5 taq nuclease assay for direct detection of campylobacter fetus subsp venerealis in clinical specimens from cattle
Journal of Clinical Microbiology, 2006Co-Authors: Lyle Mcmillen, G Fordyce, V J Doogan, Ala E LewAbstract:A Campylobacter fetus subsp. venerealis-specific 5′ Taq nuclease PCR assay using a 3′ minor groove binder-DNA probe (TaqMan MGB) was developed based on a subspecies-specific fragment of unknown identity (S. Hum, K. Quinn, J. Brunner, and S. L. On, Aust. Vet. J. 75:827-831, 1997). The assay specifically detected four C. fetus subsp. venerealis strains with no observed cross-reaction with C. fetus subsp. fetus-related Campylobacter species or other bovine venereal microflora. The 5′ Taq nuclease assay detected approximately one single cell compared to 100 and 10 cells in the conventional PCR assay and 2,500 and 25,000 cells from selective culture from inoculated Smegma and mucus, respectively. The respective detection limits following the enrichments from Smegma and mucus were 5,000 and 50 cells/inoculum for the conventional PCR compared to 500 and 50 cells/inoculum for the 5′ Taq nuclease assay. Field sampling confirmed the sensitivity and the specificity of the 5′ Taq nuclease assay by detecting an additional 40 bulls that were not detected by culture. Urine-inoculated samples demonstrated comparable detection of C. fetus subsp. venerealis by both culture and the 5′ Taq nuclease assay; however, urine was found to be less effective than Smegma for bull sampling. Three infected bulls were tested repetitively to compare sampling tools, and the bull rasper proved to be the most suitable, as evidenced by the improved ease of specimen collection and the consistent detection of higher levels of C. fetus subsp. venerealis. The 5′ Taq nuclease assay demonstrates a statistically significant association with culture (χ2 = 29.8; P < 0.001) and significant improvements for the detection of C. fetus subsp. venerealis-infected animals from crude clinical extracts following prolonged transport.
Massimo Vellante - One of the best experts on this subject based on the ideXlab platform.
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Multi-point ground-based ULF magnetic field observations in Europe during seismic active periods in 2004 and 2005
Natural Hazards and Earth System Sciences, 2008Co-Authors: G. Prattes, Konrad Schwingenschuh, H. U. Eichelberger, Werner Magnes, M. Boudjada, M. Stachel, Massimo Vellante, Viktor Wesztergom, P. NenovskiAbstract:Abstract. We present the results of ground-based Ultra Low Frequency (ULF) magnetic field measurements observed from June to August 2004 during the Bovec earthquake on 12 July 2004. Further we give information about the seismic activity in the local observatory region for an extended time span 2004 and 2005. ULF magnetic field data are provided by the South European Geomagnetic Array (SEGMA) where the experience and heritage from the CHInese MAGnetometer (CHIMAG) fluxgate magnetometer comes to application. The intensities of the horizontal H and vertical Z magnetic field and the polarization ratio R of the vertical and horizontal magnetic field intensity are analyzed taking into consideration three SEGMA observatories located at different close distances and directions from the earthquake epicenter. We observed a significant increase of high polarization ratios during strong seismic activity at the observatory nearest to the Bovec earthquake epicenter. Apart from indirect ionospheric effects electromagnetic noise could be emitted in the lithosphere due to tectonic effects in the earthquake focus region causing anomalies of the vertical magnetic field intensity. Assuming that the measured vertical magnetic field intensities are of lithospheric origin, we roughly estimate the amplitude of electromagnetic noise in the Earths crust considering an average electrical conductivity of <σ>=10−3 S/m and a certain distance of the observatory to the earthquake epicenter.
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ground satellite signatures of field line resonance a test of theoretical predictions
Journal of Geophysical Research, 2004Co-Authors: Massimo Vellante, Konrad Schwingenschuh, Viktor Wesztergom, H Luhr, T L Zhang, U Villante, M De Lauretis, A Piancatelli, M Rother, W KorenAbstract:[1] During June–July 2002 the low-altitude (h ∼ 400 km) Challenging Minisatellite Payload (CHAMP) satellite passed approximately every 2nd day close to the South European Geomagnetic Array (SEGMA, 1.56 < L < 1.88) during daytime hours. We present here the analysis of a Pc3 geomagnetic pulsation event observed simultaneously in space and at the ground array during the conjunction of 6 July 2002. Both compressional and transverse oscillations were identified in CHAMP magnetic measurements. A close correspondence between the compressional component and the ground signals is observed. The behavior of the CHAMP azimuthal component shows evidence for the occurrence of a field line resonance at L ≅ 1.6. The frequency of these azimuthal oscillations is ∼20% higher than the frequency of both the compressional oscillation and the ground pulsations. Such a difference is explained in terms of a sort of Doppler shift caused by the fast movement of the satellite across the resonance region where the phase signal changes rapidly. A further analysis verifies for the first time by space measurements the theoretical pattern of the wave polarization sense in the resonance region. The comparison with corresponding SEGMA measurements also provides an unprecedented direct confirmation of the well-known 90° rotation of the ULF wave polarization ellipse through the ionosphere.
Viktor Wesztergom - One of the best experts on this subject based on the ideXlab platform.
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Multi-point ground-based ULF magnetic field observations in Europe during seismic active periods in 2004 and 2005
Natural Hazards and Earth System Sciences, 2008Co-Authors: G. Prattes, Konrad Schwingenschuh, H. U. Eichelberger, Werner Magnes, M. Boudjada, M. Stachel, Massimo Vellante, Viktor Wesztergom, P. NenovskiAbstract:Abstract. We present the results of ground-based Ultra Low Frequency (ULF) magnetic field measurements observed from June to August 2004 during the Bovec earthquake on 12 July 2004. Further we give information about the seismic activity in the local observatory region for an extended time span 2004 and 2005. ULF magnetic field data are provided by the South European Geomagnetic Array (SEGMA) where the experience and heritage from the CHInese MAGnetometer (CHIMAG) fluxgate magnetometer comes to application. The intensities of the horizontal H and vertical Z magnetic field and the polarization ratio R of the vertical and horizontal magnetic field intensity are analyzed taking into consideration three SEGMA observatories located at different close distances and directions from the earthquake epicenter. We observed a significant increase of high polarization ratios during strong seismic activity at the observatory nearest to the Bovec earthquake epicenter. Apart from indirect ionospheric effects electromagnetic noise could be emitted in the lithosphere due to tectonic effects in the earthquake focus region causing anomalies of the vertical magnetic field intensity. Assuming that the measured vertical magnetic field intensities are of lithospheric origin, we roughly estimate the amplitude of electromagnetic noise in the Earths crust considering an average electrical conductivity of <σ>=10−3 S/m and a certain distance of the observatory to the earthquake epicenter.
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ground satellite signatures of field line resonance a test of theoretical predictions
Journal of Geophysical Research, 2004Co-Authors: Massimo Vellante, Konrad Schwingenschuh, Viktor Wesztergom, H Luhr, T L Zhang, U Villante, M De Lauretis, A Piancatelli, M Rother, W KorenAbstract:[1] During June–July 2002 the low-altitude (h ∼ 400 km) Challenging Minisatellite Payload (CHAMP) satellite passed approximately every 2nd day close to the South European Geomagnetic Array (SEGMA, 1.56 < L < 1.88) during daytime hours. We present here the analysis of a Pc3 geomagnetic pulsation event observed simultaneously in space and at the ground array during the conjunction of 6 July 2002. Both compressional and transverse oscillations were identified in CHAMP magnetic measurements. A close correspondence between the compressional component and the ground signals is observed. The behavior of the CHAMP azimuthal component shows evidence for the occurrence of a field line resonance at L ≅ 1.6. The frequency of these azimuthal oscillations is ∼20% higher than the frequency of both the compressional oscillation and the ground pulsations. Such a difference is explained in terms of a sort of Doppler shift caused by the fast movement of the satellite across the resonance region where the phase signal changes rapidly. A further analysis verifies for the first time by space measurements the theoretical pattern of the wave polarization sense in the resonance region. The comparison with corresponding SEGMA measurements also provides an unprecedented direct confirmation of the well-known 90° rotation of the ULF wave polarization ellipse through the ionosphere.
Konrad Schwingenschuh - One of the best experts on this subject based on the ideXlab platform.
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Multi-point ground-based ULF magnetic field observations in Europe during seismic active periods in 2004 and 2005
Natural Hazards and Earth System Sciences, 2008Co-Authors: G. Prattes, Konrad Schwingenschuh, H. U. Eichelberger, Werner Magnes, M. Boudjada, M. Stachel, Massimo Vellante, Viktor Wesztergom, P. NenovskiAbstract:Abstract. We present the results of ground-based Ultra Low Frequency (ULF) magnetic field measurements observed from June to August 2004 during the Bovec earthquake on 12 July 2004. Further we give information about the seismic activity in the local observatory region for an extended time span 2004 and 2005. ULF magnetic field data are provided by the South European Geomagnetic Array (SEGMA) where the experience and heritage from the CHInese MAGnetometer (CHIMAG) fluxgate magnetometer comes to application. The intensities of the horizontal H and vertical Z magnetic field and the polarization ratio R of the vertical and horizontal magnetic field intensity are analyzed taking into consideration three SEGMA observatories located at different close distances and directions from the earthquake epicenter. We observed a significant increase of high polarization ratios during strong seismic activity at the observatory nearest to the Bovec earthquake epicenter. Apart from indirect ionospheric effects electromagnetic noise could be emitted in the lithosphere due to tectonic effects in the earthquake focus region causing anomalies of the vertical magnetic field intensity. Assuming that the measured vertical magnetic field intensities are of lithospheric origin, we roughly estimate the amplitude of electromagnetic noise in the Earths crust considering an average electrical conductivity of <σ>=10−3 S/m and a certain distance of the observatory to the earthquake epicenter.
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ground satellite signatures of field line resonance a test of theoretical predictions
Journal of Geophysical Research, 2004Co-Authors: Massimo Vellante, Konrad Schwingenschuh, Viktor Wesztergom, H Luhr, T L Zhang, U Villante, M De Lauretis, A Piancatelli, M Rother, W KorenAbstract:[1] During June–July 2002 the low-altitude (h ∼ 400 km) Challenging Minisatellite Payload (CHAMP) satellite passed approximately every 2nd day close to the South European Geomagnetic Array (SEGMA, 1.56 < L < 1.88) during daytime hours. We present here the analysis of a Pc3 geomagnetic pulsation event observed simultaneously in space and at the ground array during the conjunction of 6 July 2002. Both compressional and transverse oscillations were identified in CHAMP magnetic measurements. A close correspondence between the compressional component and the ground signals is observed. The behavior of the CHAMP azimuthal component shows evidence for the occurrence of a field line resonance at L ≅ 1.6. The frequency of these azimuthal oscillations is ∼20% higher than the frequency of both the compressional oscillation and the ground pulsations. Such a difference is explained in terms of a sort of Doppler shift caused by the fast movement of the satellite across the resonance region where the phase signal changes rapidly. A further analysis verifies for the first time by space measurements the theoretical pattern of the wave polarization sense in the resonance region. The comparison with corresponding SEGMA measurements also provides an unprecedented direct confirmation of the well-known 90° rotation of the ULF wave polarization ellipse through the ionosphere.
