Objective To develop a tool capable of early and exactly predicting various outcomes in comatose survivors who restore spontaneous circulation after cardiopulmonary resuscitation （CPR） and validate its performance. ...Objective To develop a tool capable of early and exactly predicting various outcomes in comatose survivors who restore spontaneous circulation after cardiopulmonary resuscitation （CPR） and validate its performance. Methods Variables that were both readily available and predictive of outcomes were identified by systematically reviewing published literature on resuscitation. A value was assigned to these variables. We used these variables in combination with APACHE II score to devise a multifactorial prediction score system, which we called PRCSs Prognostication Score （PRCSs-PS）. Outcomes in 115 hospitalized comatose survivors after CPR were retrospectively reviewed using PRCSs-PS. Score of patients with different outcomes was compared. The area under the receiver- operating characteristic （ROC） curve was determined to evaluate performance of this tool to identify patients with a poor outcome （CPC4 and 5） and other outcomes （CPC1, 2, and 3）. Results There were differences of PRCSs-PS score among multiple groups with five different outcomes （CPC 1-5）（F=65.91, P=0.000）. Pairwise groups with different CPC were compared： no significant difference was noted between CPC1 and CPC2 （12.41±6.49 vs 17.38±6.91,P=0.092）, but difference between other pairwise CPC groups was statistically significant （CPC2 vs CPC3：17.38±6.91 vs 24.50±5.80, P=0.041, CPC3 vs CPC4：24.50±5.80 vs 32.29±5.24, P=0.006）. The performance of PRCSs-PS to discriminate patients with a poor outcome from patients with other outcomes went as follows： it had 100% sensitivity, 78.6% specificity, and 178.6 diagnostic index at the score cut-off22.5; it had 77.8% sensitivity, 100% specificity and 176.4 diagnostic index at the score cut-off32.5. Score 23 and 33 were two key cut-offpoints. The area under the ROC curve was 0.968, showing excellent discrimination. Conclusions The final outcomes in post-resuscitation comatose survivors can be accurately predicted using PRCSs-PS Score.展开更多
AIM:To determine whether and how magnetic resonance imaging(MRI)-based total liver volume(TLV) and diffusion weighted imaging(DWI) could predict liver fibrosis.METHODS:Sixteen experimental mature mini-pigs(6 males,10 ...AIM:To determine whether and how magnetic resonance imaging(MRI)-based total liver volume(TLV) and diffusion weighted imaging(DWI) could predict liver fibrosis.METHODS:Sixteen experimental mature mini-pigs(6 males,10 females),weighing between 20.0 and 24.0 kg were prospectively used to model liver fibrosis induced by intraperitoneal injection of 40% CCl4 dissolved in fat emulsion twice a week for 16 wk,and by feeding 40% CCl4 mixed with maize flour twice daily for the subsequent 5 wk.All the survival animals underwent percutaneous liver biopsy and DWI using b = 300,500 and 800 s/mm2 followed by abdominal gadolinium-enhanced MRI at the 0,5th,9th,16th and 21st weekend after beginning of the modeling.TLV was obtained on enhanced MRI,and apparent diffusion coefficient(ADC) was obtained on DWI.Hepatic tissue specimens were stained with hematoxylin and Masson' s trichrome staining for staging liver fibrosis.Pathological specimens were scored using the human METAVIR classification system.Statistical analyses were performed to determine whether and how the TLV and ADC could be used to predict the stage of liver fibrosis.RESULTS:TLV increased from stage 0 to 2 and decreased from stage 3(r = 0.211;P < 0.001).There was a difference in TLV between stage 0-1 and 2-4(P = 0.03) whereas no difference between stage 0-2 and 3-4(P = 0.71).TLV could predict stage ≥ 2 [area under receiver operating characteristic curve(AUC) = 0.682].There was a decrease in ADC values with increasing stage of fibrosis for b = 300,500 and 800 s/mm2(r =-0.418,-0.535 and-0.622,respectively;all P < 0.001).Differences were found between stage 0-1 and 2-4 in ADC values for b = 300,500 and 800 s/mm2,and between stage 0-2 and 3-4 for b = 500 or 800 s/mm2(all P < 0.05).For predicting stage ≥ 2 and ≥ 3,AUC was 0.803 and 0.847 for b = 500 s/mm2,and 0.848 and 0.887 for b = 800 s/mm2,respectively.CONCLUSION:ADC for b = 500 or 800 s/mm2 could be better than TLV and ADC for b = 300 s/mm2 to pre-dict fibrosis stage ≥ 2 or ≥ 3.展开更多
Experimental investigation of stepped and straight-through labyrinth seals was designed to study the sealing performance of two different typical labyrinth seals.In order to facilitate dimensional analysis on the flow...Experimental investigation of stepped and straight-through labyrinth seals was designed to study the sealing performance of two different typical labyrinth seals.In order to facilitate dimensional analysis on the flow resistance characteristics of labyrinth seals,the variable cross-section of the flow channels are considered as constant cross-section flow.The mechanical energy loss of flow caused by throttle turbulence intensity is considered as caused by friction along the way.The friction coefficient of stepped labyrinth seals is bigger than that of straight-through labyrinth seals by more than 40% for the same Reynolds number and the ratio of equivalent diameter and the seal length.The expression of friction coefficient /and /Re are obtained from experimental data.The verifications indicate that the expressions are highly accurate.The contribution to the total pressure drop of each tooth cavity gradually becomes less along the flow direction.展开更多
文摘Objective To develop a tool capable of early and exactly predicting various outcomes in comatose survivors who restore spontaneous circulation after cardiopulmonary resuscitation （CPR） and validate its performance. Methods Variables that were both readily available and predictive of outcomes were identified by systematically reviewing published literature on resuscitation. A value was assigned to these variables. We used these variables in combination with APACHE II score to devise a multifactorial prediction score system, which we called PRCSs Prognostication Score （PRCSs-PS）. Outcomes in 115 hospitalized comatose survivors after CPR were retrospectively reviewed using PRCSs-PS. Score of patients with different outcomes was compared. The area under the receiver- operating characteristic （ROC） curve was determined to evaluate performance of this tool to identify patients with a poor outcome （CPC4 and 5） and other outcomes （CPC1, 2, and 3）. Results There were differences of PRCSs-PS score among multiple groups with five different outcomes （CPC 1-5）（F=65.91, P=0.000）. Pairwise groups with different CPC were compared： no significant difference was noted between CPC1 and CPC2 （12.41±6.49 vs 17.38±6.91,P=0.092）, but difference between other pairwise CPC groups was statistically significant （CPC2 vs CPC3：17.38±6.91 vs 24.50±5.80, P=0.041, CPC3 vs CPC4：24.50±5.80 vs 32.29±5.24, P=0.006）. The performance of PRCSs-PS to discriminate patients with a poor outcome from patients with other outcomes went as follows： it had 100% sensitivity, 78.6% specificity, and 178.6 diagnostic index at the score cut-off22.5; it had 77.8% sensitivity, 100% specificity and 176.4 diagnostic index at the score cut-off32.5. Score 23 and 33 were two key cut-offpoints. The area under the ROC curve was 0.968, showing excellent discrimination. Conclusions The final outcomes in post-resuscitation comatose survivors can be accurately predicted using PRCSs-PS Score.
基金Supported by National Natural Science Foundation of China,No. 81050033Key Projects in the Sichuan Province Science and Technology Pillar Program,No. 2011SZ0237the Science Fund for Distinguished Young Scholars of Sichuan Province,China,No. 2010JQ0039
文摘AIM:To determine whether and how magnetic resonance imaging(MRI)-based total liver volume(TLV) and diffusion weighted imaging(DWI) could predict liver fibrosis.METHODS:Sixteen experimental mature mini-pigs(6 males,10 females),weighing between 20.0 and 24.0 kg were prospectively used to model liver fibrosis induced by intraperitoneal injection of 40% CCl4 dissolved in fat emulsion twice a week for 16 wk,and by feeding 40% CCl4 mixed with maize flour twice daily for the subsequent 5 wk.All the survival animals underwent percutaneous liver biopsy and DWI using b = 300,500 and 800 s/mm2 followed by abdominal gadolinium-enhanced MRI at the 0,5th,9th,16th and 21st weekend after beginning of the modeling.TLV was obtained on enhanced MRI,and apparent diffusion coefficient(ADC) was obtained on DWI.Hepatic tissue specimens were stained with hematoxylin and Masson' s trichrome staining for staging liver fibrosis.Pathological specimens were scored using the human METAVIR classification system.Statistical analyses were performed to determine whether and how the TLV and ADC could be used to predict the stage of liver fibrosis.RESULTS:TLV increased from stage 0 to 2 and decreased from stage 3(r = 0.211;P < 0.001).There was a difference in TLV between stage 0-1 and 2-4(P = 0.03) whereas no difference between stage 0-2 and 3-4(P = 0.71).TLV could predict stage ≥ 2 [area under receiver operating characteristic curve(AUC) = 0.682].There was a decrease in ADC values with increasing stage of fibrosis for b = 300,500 and 800 s/mm2(r =-0.418,-0.535 and-0.622,respectively;all P < 0.001).Differences were found between stage 0-1 and 2-4 in ADC values for b = 300,500 and 800 s/mm2,and between stage 0-2 and 3-4 for b = 500 or 800 s/mm2(all P < 0.05).For predicting stage ≥ 2 and ≥ 3,AUC was 0.803 and 0.847 for b = 500 s/mm2,and 0.848 and 0.887 for b = 800 s/mm2,respectively.CONCLUSION:ADC for b = 500 or 800 s/mm2 could be better than TLV and ADC for b = 300 s/mm2 to pre-dict fibrosis stage ≥ 2 or ≥ 3.
基金supported by National Key Technology R&D Program(2012BAB12B02)
文摘Experimental investigation of stepped and straight-through labyrinth seals was designed to study the sealing performance of two different typical labyrinth seals.In order to facilitate dimensional analysis on the flow resistance characteristics of labyrinth seals,the variable cross-section of the flow channels are considered as constant cross-section flow.The mechanical energy loss of flow caused by throttle turbulence intensity is considered as caused by friction along the way.The friction coefficient of stepped labyrinth seals is bigger than that of straight-through labyrinth seals by more than 40% for the same Reynolds number and the ratio of equivalent diameter and the seal length.The expression of friction coefficient /and /Re are obtained from experimental data.The verifications indicate that the expressions are highly accurate.The contribution to the total pressure drop of each tooth cavity gradually becomes less along the flow direction.
