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Plumb RS Stumpf CL Gorenstein MV Castro-Perez JM Dear GJ Anthony M Sweatman BC Connor SC Haselden JN 《Rapid communications in mass spectrometry : RCM》2002,16(20):1991-1996
The application of liquid chromatography/mass spectrometry (LC/MS) followed by principal components analysis (PCA) has been successfully applied to the screening of rat urine following the administration of three candidate pharmaceuticals. With this methodology it was possible to differentiate the control samples from the dosed samples and to identify the components of the mass spectrum responsible for the separation. These data clearly show that LC/MS is a viable alternative, or complementary, technique to proton NMR for metabonomics applications in drug discovery and development. 相似文献
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G. J. Dear D. N. Mallett D. M. Higton A. D. Roberts S. A. Bird H. Young R. S. Plumb I. M. Ismail 《Chromatographia》2002,55(3-4):177-184
Summary In this paper we investigate the potential of alkyl-bonded silica monolithic columns for the isolation and identification
of drug-related components in biological fluids. Up to 6 columns have been connected in series to produce a chromatographic
system with up to 40,000 plates. This high-resolution chromatography system has been coupled to both MS and NMR to enable
efficient detection and characterisation of drug-related components in biological fluids. The use of six coupled columns has
been shown to give enhanced resolution over a high quality silica particulate column packed with 3 μm material which exhibits
the same back pressure. The effect of volume and mass load on the performance of monolithic columns for semi-preparative chromatography
of biological fluids has also been investigated. In these studies it was possible to inject up to 100 mL of neat urine with
no loss of chromatographic performance. Furthermore, upon re-testing, the columns showed similar chromatographic performance.
Again several columns were serially connected, producing enhanced resolution in the semi-preparative mode. 相似文献
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Zheng J. Maharaj C. Liu J. Chai H. Liu H. Dear J. P. 《Mechanics of Composite Materials》2022,58(1):125-140
Mechanics of Composite Materials - In this research, the maximum stress, Hashin, Puck, LaRC03, and Northwestern University (NU) criteria are analyzed based literature data, analytical results... 相似文献
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Validation of Sun Exposure Reported Annually Against Interim Self‐report and Daily Sun Diaries 下载免费PDF全文
Laura King Fan Xiang Ashwin Swaminathan Keith Dear Simone L. Harrison Ingrid van der Mei Michael G. Kimlin Catherine D'Este Robyn M. Lucas 《Photochemistry and photobiology》2017,93(5):1294-1302
Data on personal sun exposure over a period exceeding the immediate past days or weeks are typically self‐reported in brief questionnaire items. The validity of such self‐reporting of longer term personal sun exposure, for example over a year, including detail on variation across seasons, has not previously been investigated. In a volunteer sample (n = 331) of Australian adults aged 18 years and over, we assessed the 12‐month reliability of sun exposure reported separately for each season, and its accuracy compared to a daily sun diary in the same season. Seasonal time outdoors displayed fair‐to‐good reliability between baseline and end of study (12 months), with responses showing higher agreement at lower levels of time outdoors. There was good agreement for ranking of individuals' time outdoors with the daily sun diary data, although the actual diary time outdoors was typically considerably lower than the self‐reported questionnaire data. Place of residence, education, being a smoker, day of the week (i.e. working day vs nonworking day) and working mainly outdoors were significant predictors of agreement. While participants overestimated their actual time outdoors, the self‐report questionnaire provided a valid ranking of long‐term sun exposure against others in the study that was reliable over time. 相似文献
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Finneran JJ Schlundt CE Dear R Carder DA Ridgway SH 《The Journal of the Acoustical Society of America》2002,111(6):2929-2940
A behavioral response paradigm was used to measure masked underwater hearing thresholds in a bottlenose dolphin (Tursiops truncatus) and a white whale (Delphinapterus leucas) before and after exposure to single underwater impulsive sounds produced from a seismic watergun. Pre- and postexposure thresholds were compared to determine if a temporary shift in masked hearing thresholds (MTTS), defined as a 6-dB or larger increase in postexposure thresholds, occurred. Hearing thresholds were measured at 0.4, 4, and 30 kHz. MTTSs of 7 and 6 dB were observed in the white whale at 0.4 and 30 kHz, respectively, approximately 2 min following exposure to single impulses with peak pressures of 160 kPa, peak-to-peak pressures of 226 dB re 1 microPa, and total energy fluxes of 186 dB re 1 microPa2 x s. Thresholds returned to within 2 dB of the preexposure value approximately 4 min after exposure. No MTTS was observed in the dolphin at the highest exposure conditions: 207 kPa peak pressure, 228 dB re 1 microPa peak-to-peak pressure, and 188 dB re 1 microPa2 x s total energy flux. 相似文献
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Schlundt CE Dear RL Houser DS Bowles AE Reidarson T Finneran JJ 《The Journal of the Acoustical Society of America》2011,129(2):1111-1116
The hearing sensitivities of two short-finned pilot whales (Globicephala macrorhynchus) were investigated by measuring auditory evoked potentials generated in response to clicks and sinusoidal amplitude modulated (SAM) tones. The first whale tested, an adult female, was a long-time resident at SeaWorld San Diego with a known health history. Click-evoked responses in this animal were similar to those measured in other echolocating odontocetes. Auditory thresholds were comparable to dolphins of similar age determined with similar evoked potential methods. The region of best sensitivity was near 40 kHz and the upper limit of functional hearing was between 80 and 100 kHz. The second whale tested, a juvenile male, was recently stranded and deemed non-releasable. Click-evoked potentials were not detected in this animal and testing with SAM tones suggested severe hearing loss above 10 kHz. 相似文献
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Finneran JJ Schlundt CE Branstetter B Dear RL 《The Journal of the Acoustical Society of America》2007,122(2):1249-1264
Hearing sensitivity was measured in a bottlenose dolphin before and after exposure to an intense 20-kHz fatiguing tone in three different experiments. In each experiment, hearing was characterized using both the auditory steady-state response (ASSR) and behavioral methods. In experiments 1 and 2, ASSR stimuli consisted of seven frequency-modulated tones, each with a unique carrier and modulation frequency. The tones were simultaneously presented to the subject and the ASSR at each modulation rate measured to determine the effects of the sound exposure at the corresponding carrier frequency. In experiment 3 behavioral thresholds and ASSR input-output functions were measured at a single frequency before and after three exposures. Hearing loss was frequency-dependent, with the largest temporary threshold shifts occurring (in order) at 30, 40, and 20 kHz. ASSR threshold shifts reached 40-45 dB and were always larger than behavioral shifts (19-33 dB). The ASSR input-output functions were represented as the sum of two processes: a low threshold, saturating process and a higher threshold, linear process, that react and recover to fatigue at different rates. The loss of the near-threshold saturating process after exposure may explain the discrepancies between the ASSR and behavioral threshold shifts. 相似文献
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The coupling of ultra-performance liquid chromatography, operating at elevated pressures, to a linear ion trap mass spectrometer provides a high-performance system suitable for drug metabolite characterisation. This system demonstrates improved chromatographic efficiency and sensitivity and at the same time provides diagnostic MSn data often critical for metabolite structural assignment. The linear ion trap was capable of dealing with the high chromatographic efficiencies and hence narrow peak widths associated with 1.7 microm particle-packed column separations. Polarity switching and data-dependent MSn data were generated with ease, and applied to the identification of metabolites found in human plasma. 相似文献