Background: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound(TTUS) perivascular flow probe technology is widely used in clini...Background: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound(TTUS) perivascular flow probe technology is widely used in clinical practice to evaluate the hepatic inflow, yet invasive. The phase-contrast-MRI(PC-MRI) is not invasive and potentially applicable in assessing the hepatic blood flow. In the present study, we compared the hepatic inflow rates using the PC-MRI and the TTUS probe, and evaluated their predictive value of post-hepatectomy adverse events. Methods: Eighteen large white pigs were anaesthetized for PC-MRI and approximately 75% hepatic resection was performed under a unified protocol. The blood flow was measured in the hepatic artery(Qha), the portal vein(Qpv), and the aorta above the celiac trunk(Qca) using PC-MRI, and was compared to the TTUS probe. The Bland-Altman method was conducted and a partial least squares regression(PLS) model was implemented. Results: The mean Qpv measured in PC-MRI was 0.55 ± 0.12 L/min, and in the TTUS probe was 0.74 ± 0.17 L/min. Qca was 1.40 ± 0.47 L/min in the PC-MRI and 2.00 ± 0.60 L/min in the TTUS probe. Qha was 0.17 ± 0.10 L/min in the PC-MRI, and 0.13 ± 0.06 L/min in the TTUS probe. The Bland-Altman method revealed that the estimated bias of Qca in the PC-MRI was 32%(95% CI:-49% to 15%); Qha 17%(95% CI:-15% to 51%); and Qpv 40%(95% CI:-62% to 18%). The TTUS probe had a higher weight in predicting adverse outcomes after 75% resection compared to the PC-MRI( β= 0.35 and 0.43 vs β = 0.22 and 0.07, for tissue changes and premature death, respectively). Conclusions: There is a tendency of the PC-MRI to underestimate the flow measured by the TTUS probes. The TTUS probe measures are more predictive of relevant post-hepatectomy outcomes.展开更多
In this paper,we propose a novel probe to identify phases in any two-phase flows where one phase is conductive and the other nonconductive.We can further obtain many parameters such as void fraction,bubble velocity,an...In this paper,we propose a novel probe to identify phases in any two-phase flows where one phase is conductive and the other nonconductive.We can further obtain many parameters such as void fraction,bubble velocity,and interfacial area concentration.Compared with the traditional probe,the novel probe has unique advantages that it is less dependent on water conductance or distance between the electrodes,and that the amplitude is bigger between high and low levels.Theoretical analyses showed that the measurement error became higher when water conductance decreases or distance increases,which is consistent with the theoretical analyses.Experimental results showed that the output signal kept constant with salt content of 0-5% and electrode distance of 0-30 mm in tap water.The level difference was up to 6.4 V,resulting in identifying two phases easily.Time traces of phase identification were completely consistent with the flow structures.展开更多
Zonal flows have been measured with several novel Langmuir probe array on the HT-7 tokamak since 2002. The forked probe and its improved generation, the farmer forked probe were designed based on the original idea of ...Zonal flows have been measured with several novel Langmuir probe array on the HT-7 tokamak since 2002. The forked probe and its improved generation, the farmer forked probe were designed based on the original idea of the Reynolds stress triple tips array. In order to measure the radial shearing rate of zonal flows, the pyramid probe was also designed. This paper addresses the technical aspects regarding this new application. Since the zonal flows dynamics is now widely believed crucial to plasma confinement physics, an important application field of Langmuir probe was opened up.展开更多
To identify flow patterns in horizontal gas-liquid flows,a single-wire capacitance probe was used for voltage output for the first time.Regardless of the measurement accuracy of water layer height,the statistic parame...To identify flow patterns in horizontal gas-liquid flows,a single-wire capacitance probe was used for voltage output for the first time.Regardless of the measurement accuracy of water layer height,the statistic parameters of the voltage-time traces were compared within the same sampling time of 5s under different flow patterns,including maximum,minimum,range,and average.The results show that most of flow pattens were accurately identified except for some transition lines.展开更多
Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2...Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2005. Specific aspects of the design and the mission of IRDT are briefly outlined. The preliminary results of the recent flight of IRDT and the methodology followed at ESTEC for the assessment of radiative fluxes for Huygens are summarised.展开更多
基金supported mainly by the “Agence de la Biomedecine” through its program of Research(AOR 2009)BM,AC,BP,WM,VCI and VE acknowledged funding of project ANR-13-TECS-0006 by the Agence Nationale de la Recherche
文摘Background: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound(TTUS) perivascular flow probe technology is widely used in clinical practice to evaluate the hepatic inflow, yet invasive. The phase-contrast-MRI(PC-MRI) is not invasive and potentially applicable in assessing the hepatic blood flow. In the present study, we compared the hepatic inflow rates using the PC-MRI and the TTUS probe, and evaluated their predictive value of post-hepatectomy adverse events. Methods: Eighteen large white pigs were anaesthetized for PC-MRI and approximately 75% hepatic resection was performed under a unified protocol. The blood flow was measured in the hepatic artery(Qha), the portal vein(Qpv), and the aorta above the celiac trunk(Qca) using PC-MRI, and was compared to the TTUS probe. The Bland-Altman method was conducted and a partial least squares regression(PLS) model was implemented. Results: The mean Qpv measured in PC-MRI was 0.55 ± 0.12 L/min, and in the TTUS probe was 0.74 ± 0.17 L/min. Qca was 1.40 ± 0.47 L/min in the PC-MRI and 2.00 ± 0.60 L/min in the TTUS probe. Qha was 0.17 ± 0.10 L/min in the PC-MRI, and 0.13 ± 0.06 L/min in the TTUS probe. The Bland-Altman method revealed that the estimated bias of Qca in the PC-MRI was 32%(95% CI:-49% to 15%); Qha 17%(95% CI:-15% to 51%); and Qpv 40%(95% CI:-62% to 18%). The TTUS probe had a higher weight in predicting adverse outcomes after 75% resection compared to the PC-MRI( β= 0.35 and 0.43 vs β = 0.22 and 0.07, for tissue changes and premature death, respectively). Conclusions: There is a tendency of the PC-MRI to underestimate the flow measured by the TTUS probes. The TTUS probe measures are more predictive of relevant post-hepatectomy outcomes.
基金Support by the National Natural Science Foundation of China (No. 51006068)
文摘In this paper,we propose a novel probe to identify phases in any two-phase flows where one phase is conductive and the other nonconductive.We can further obtain many parameters such as void fraction,bubble velocity,and interfacial area concentration.Compared with the traditional probe,the novel probe has unique advantages that it is less dependent on water conductance or distance between the electrodes,and that the amplitude is bigger between high and low levels.Theoretical analyses showed that the measurement error became higher when water conductance decreases or distance increases,which is consistent with the theoretical analyses.Experimental results showed that the output signal kept constant with salt content of 0-5% and electrode distance of 0-30 mm in tap water.The level difference was up to 6.4 V,resulting in identifying two phases easily.Time traces of phase identification were completely consistent with the flow structures.
基金supported by National Natural Science Foundation of China(No.10235010)
文摘Zonal flows have been measured with several novel Langmuir probe array on the HT-7 tokamak since 2002. The forked probe and its improved generation, the farmer forked probe were designed based on the original idea of the Reynolds stress triple tips array. In order to measure the radial shearing rate of zonal flows, the pyramid probe was also designed. This paper addresses the technical aspects regarding this new application. Since the zonal flows dynamics is now widely believed crucial to plasma confinement physics, an important application field of Langmuir probe was opened up.
基金Supported by Postdoctoral Foundation of P R China(Grant No:20080440619)
文摘To identify flow patterns in horizontal gas-liquid flows,a single-wire capacitance probe was used for voltage output for the first time.Regardless of the measurement accuracy of water layer height,the statistic parameters of the voltage-time traces were compared within the same sampling time of 5s under different flow patterns,including maximum,minimum,range,and average.The results show that most of flow pattens were accurately identified except for some transition lines.
文摘Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2005. Specific aspects of the design and the mission of IRDT are briefly outlined. The preliminary results of the recent flight of IRDT and the methodology followed at ESTEC for the assessment of radiative fluxes for Huygens are summarised.
