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Cometabolism, as a complex phenomenon in microbial world, is a special mechanism for transformation of many compounds of environmental and toxicological significance. Several models have been proposed to describe the cometabolic transformations of non-growth substrates in the absence or presence of growth substrates. In this study, a model was proposed to simulate the degradation kinetics of phenol and ethanethiol (ET) by a pure culture of Ralstonia eutropha, including the effects of cell growth, endogenous cell decay, loss of transformation activity, competitive inhibition between growth and non-growth substrates, and self-inhibition of non-growth substrate. The model parameters were determined independently and were then used for evaluating the applicability of the model by comparing experimental data with model predictions. The model successfully predicted ET transformation and phenol utilization for a wide range of concentrations of ET (0 ~ 40 mg/L) and phenol (0 ~ 100 mg/L). 相似文献
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Efficient retroviral infection of mammalian cells is blocked by inhibition of poly(ADP-ribose) polymerase activity. 总被引:1,自引:4,他引:1
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Farzaneh Harraf Anil K Sharma Martin M Brown Kennedy R Lees Richard I Vass Lalit Kalra 《BMJ (Clinical research ed.)》2002,325(7354):17
ObjectiveTo investigate delays in the presentation to hospital and evaluation of patients with suspected stroke.DesignMulticentre prospective observational study.Setting22 hospitals in the United Kingdom and Dublin.Participants739 patients with suspected stroke presenting to hospital.ResultsThe median age of patients was 75 years, and 400 were women. The median delay between onset of symptoms and arrival at hospital was 6 hours (interquartile range 1 hour 48 minutes to 19 hours 12 minutes). 37% of patients arrived within 3 hours, 50% within 6 hours. The median delay for patients using the emergency service was 2 hours 3 minutes (47 minutes to 7 hours 12 minutes) compared with 7 hours 12 minutes (2 hours 5 minutes to 20 hours 37 minutes) for referrals from general practitioners (P<0.0001). Use of emergency services reduced delays to hospital (odds ratio 0.45, 95% confidence interval 0.23 to 0.61). The median time to evaluation by a senior doctor was 1 hour 9 minutes (interquartile range 33 minutes to 1 hour 50 minutes) but was undertaken in only 477 (65%) patients within 3 hours of arrival. This was not influenced by age, sex, time of presentation, mode of referral, hospital type, or the presence of a stroke unit. Computed tomography was requested within 3 hours of arrival in 166 (22%) patients but undertaken in only 60 (8%).ConclusionDelays in patients arriving at hospital with suspected stroke can be reduced by the increased use of emergency services. Over a third of patients arrive at hospital within three hours of stroke; their management can be improved by expediting medical evaluation and performing computed tomography early.