AIM:To investigate short-and long-term intraocular pressure(IOP)fluctuations and fur ther ocular and demographic parameters as predictors for normal tension glaucoma(NTG)progression.METHODS:This retrospective,longitud...AIM:To investigate short-and long-term intraocular pressure(IOP)fluctuations and fur ther ocular and demographic parameters as predictors for normal tension glaucoma(NTG)progression.METHODS:This retrospective,longitudinal cohort study included 137 eyes of 75 patients with NTG,defined by glaucomatous optic disc or visual field defect with normal IOP(<21 mm Hg),independently from therapy regimen.IOP fluctuation,mean,and maximum were inspected with a mean follow-up of 38 mo[standard deviation(SD)18 mo].Inclusion criteria were the performance of minimum two 48-hour profiles including perimetry,Heidelberg retina tomograph(HRT)imaging,and optic disc photographs.The impact of IOP parameters,myopia,sex,cup-to-disc-ratio,and visual field results on progression of NTG were analyzed using Cox regression models.A sub-group analysis with results from optical coherence tomography(OCT)was performed.RESULTS:IOP fluctuations,average,and maximum were not risk factors for progression in NTG patients,although maximum IOP at the initial IOP profile was higher in eyes with progression than in eyes without progression(P=0.054).The 46/137(33.5%)eyes progressed over the followup period.Overall progression(at least three progression confirmations)occurred in 28/137 eyes(20.4%).Most progressions were detected by perimetry(36/46).Longterm IOP mean over all pressure profiles was 12.8 mm Hg(SD 1.3 mm Hg);IOP fluctuation was 1.4 mm Hg(SD 0.8 mm Hg).The progression-free five-year rate was 58.2%(SD 6.5%).CONCLUSION:Short-and long-term IOP fluctuations do not result in progression of NTG.As functional changes are most likely to happen,NTG should be monitored with visual field testing more often than with other devices.展开更多
To improve the separation efficiency of air dense medium fluidized beds tor dry coal preparation, a gasvibro fluidized bed has been proposed in which magnetic powder is used as the heavy medium. Pressure fluctuations ...To improve the separation efficiency of air dense medium fluidized beds tor dry coal preparation, a gasvibro fluidized bed has been proposed in which magnetic powder is used as the heavy medium. Pressure fluctuations in the gas-vibro fluidized bed were investigated using time- and frequency-domain analysis methods. The relationship between pressure fluctuations, bubble behavior, and separation efficiency was established. The low amplitude of the standard deviation, the power spectral density （PSD）, the incoherent-output PSD, and the high amplitude of the coherent-output PSD, which corresponds to the bubble behavior in the bed, were improved for coal preparation. The coal ash content was reduced from 42.5570 to 16.54% by using the gas-vibro fluidized bed.展开更多
Experimental observations show that the random process of two phase flow behind an aerator is an ergodic process and its amplitude distribution is similar to a normal distribution. The maximum pressure fluctuation is ...Experimental observations show that the random process of two phase flow behind an aerator is an ergodic process and its amplitude distribution is similar to a normal distribution. The maximum pressure fluctuation is at the re attachment point where the jet trajectory flow over the aerator re attaches to bottom of the channel, and its amplitude is 2 3 times larger than when there is no aerator. There is a dominant frequency of 1 24 Hz in the model, but the coherence in the frequency domain is not obvious for other frequencies beside the dominant frequency. There is a large vortex at the re attachment point behind the aerator but correlation among the measurement points is not obvious in the time domain.展开更多
基金a DFG(German Research Foundation)Grant(HO 3277/2-1)。
文摘AIM:To investigate short-and long-term intraocular pressure(IOP)fluctuations and fur ther ocular and demographic parameters as predictors for normal tension glaucoma(NTG)progression.METHODS:This retrospective,longitudinal cohort study included 137 eyes of 75 patients with NTG,defined by glaucomatous optic disc or visual field defect with normal IOP(<21 mm Hg),independently from therapy regimen.IOP fluctuation,mean,and maximum were inspected with a mean follow-up of 38 mo[standard deviation(SD)18 mo].Inclusion criteria were the performance of minimum two 48-hour profiles including perimetry,Heidelberg retina tomograph(HRT)imaging,and optic disc photographs.The impact of IOP parameters,myopia,sex,cup-to-disc-ratio,and visual field results on progression of NTG were analyzed using Cox regression models.A sub-group analysis with results from optical coherence tomography(OCT)was performed.RESULTS:IOP fluctuations,average,and maximum were not risk factors for progression in NTG patients,although maximum IOP at the initial IOP profile was higher in eyes with progression than in eyes without progression(P=0.054).The 46/137(33.5%)eyes progressed over the followup period.Overall progression(at least three progression confirmations)occurred in 28/137 eyes(20.4%).Most progressions were detected by perimetry(36/46).Longterm IOP mean over all pressure profiles was 12.8 mm Hg(SD 1.3 mm Hg);IOP fluctuation was 1.4 mm Hg(SD 0.8 mm Hg).The progression-free five-year rate was 58.2%(SD 6.5%).CONCLUSION:Short-and long-term IOP fluctuations do not result in progression of NTG.As functional changes are most likely to happen,NTG should be monitored with visual field testing more often than with other devices.
基金supported financially by the National Key Basic Research Program of China(973 Program,No.2012CB214904)the National Natural Science Foundation of China(Nos.51221462,51134022,51304196,and 91434133)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education(No.20120095130001)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘To improve the separation efficiency of air dense medium fluidized beds tor dry coal preparation, a gasvibro fluidized bed has been proposed in which magnetic powder is used as the heavy medium. Pressure fluctuations in the gas-vibro fluidized bed were investigated using time- and frequency-domain analysis methods. The relationship between pressure fluctuations, bubble behavior, and separation efficiency was established. The low amplitude of the standard deviation, the power spectral density （PSD）, the incoherent-output PSD, and the high amplitude of the coherent-output PSD, which corresponds to the bubble behavior in the bed, were improved for coal preparation. The coal ash content was reduced from 42.5570 to 16.54% by using the gas-vibro fluidized bed.
文摘Experimental observations show that the random process of two phase flow behind an aerator is an ergodic process and its amplitude distribution is similar to a normal distribution. The maximum pressure fluctuation is at the re attachment point where the jet trajectory flow over the aerator re attaches to bottom of the channel, and its amplitude is 2 3 times larger than when there is no aerator. There is a dominant frequency of 1 24 Hz in the model, but the coherence in the frequency domain is not obvious for other frequencies beside the dominant frequency. There is a large vortex at the re attachment point behind the aerator but correlation among the measurement points is not obvious in the time domain.
