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René van den Berg,Jenna J. Wildeman,Olvert A. Berkhemer,Rogier V. Immink,Henk A. Marquering,Charles B.L.M. Majoie,Dagmar Verbaan,Ed T. van Bavel 대한신경중재치료의학회 2020 Neurointervention Vol.15 No.3
Purpose: In acute middle cerebral artery (MCA) occlusion, collateral vessels provide retrograde supply to the occluded territory. We hypothesized that such collateral flow reduces perfusion of the non-occluded donor region (steal effect).Materials and Methods: Patients with an MCA occlusion with opacification of both ipsi- and contralateral anterior cerebral arteries (ACA) on angiography prior to endovascular treatment were selected. Arteriovenous transit time (AVTT) for both ACA territories was compared for different grades of collateral supply to the MCA territory. In addition, the influence of diabetes and hypertension was analyzed. After successful revascularization, AVTT was re-assessed to determine reversibility.Results: Forty-one patients were analyzed. An AVTT of 8.6 seconds (standard deviation [SD] 2.4 seconds) was seen in the ACA territory of the affected hemisphere in comparison to 6.6 seconds (SD 2.1 seconds) for the contralateral side (P<0.001). A more prolonged (but not significant) AVTT was seen in cases with a higher collateral grade. No difference in AVTT was seen in patients with diabetes or hypertension. After successful MCA revascularization, AVTT delay was 7.4 seconds (SD 2.1 seconds).Conclusion: A cerebral steal effect occurs in patients with an acute MCA occlusion, probably related to augmented flow to the penumbra area.
Wolfgang G. Kunz,Peter B. Sporns,Marios N. Psychogios,Jens Fiehler,René Chapot,Franziska Dorn,Astrid Grams,Andrea Morotti,Patricia Musolino,Sarah Lee,André Kemmling,Hans Henkes,Omid Nikoubashman,Marti 대한뇌졸중학회 2022 Journal of stroke Vol.24 No.1
Background and Purpose The Save ChildS Study demonstrated that endovascular thrombectomy (EVT) is a safe treatment option for pediatric stroke patients with large vessel occlusions (LVOs) with high recanalization rates. Our aim was to determine the long-term cost, health consequences and cost-effectiveness of EVT in this patient population. Methods In this retrospective study, a decision-analytic Markov model estimated lifetime costs and quality-adjusted life years (QALYs). Early outcome parameters were based on the entire Save ChildS Study to model the EVT group. As no randomized data exist, the Save ChildS patient subgroup with unsuccessful recanalization was used to model the standard of care group. For modeling of lifetime estimates, pediatric and adult input parameters were obtained from the current literature. The analysis was conducted in a United States setting applying healthcare and societal perspectives. Probabilistic sensitivity analyses were performed. The willingness-to-pay threshold was set to $100,000 per QALY. Results The model results yielded EVT as the dominant (cost-effective as well as cost-saving) strategy for pediatric stroke patients. The incremental effectiveness for the average age of 11.3 years at first stroke in the Save ChildS Study was determined as an additional 4.02 lifetime QALYs, with lifetime cost-savings that amounted to $169,982 from a healthcare perspective and $254,110 when applying a societal perspective. Acceptability rates for EVT were 96.60% and 96.66% for the healthcare and societal perspectives. Conclusions EVT for pediatric stroke patients with LVOs resulted in added QALY and reduced lifetime costs. Based on the available data in the Save ChildS Study, EVT is very likely to be a cost-effective treatment strategy for childhood stroke.
Lotte E. de Groot-de Laat,Jackie McGhie,Ben Ren,René Frowijn,Frans B. Oei,Marcel L. Geleijnse 한국심초음파학회 2019 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.27 No.3
In this report, we provide an overview of a new, updated echocardiographic classification of mitral regurgitation mechanisms to provide a more comprehensive and detailed assessment of mitral valve disorders. This is relevant to modern mitral valve repair techniques, with special attention to the added value of 3D-echocardiography.
Sun, G.A.,Wang, X.L.,Wang, Y.D.,Woo, W.C.,Wang, H.,Liu, X.P.,Chen, B.,Fu, Y.Q.,Sheng, L.S.,Ren, Y. Elsevier Sequoia 2013 Materials science & engineering. properties, micro Vol.560 No.-
High-energy synchrotron X-ray diffraction technique was used to in-situ characterize microstructure, lattice strain, and phase transition behavior of a Ni<SUB>47</SUB>Ti<SUB>44</SUB>Nb<SUB>9</SUB> shape memory alloy. Phase transformation kinetics and deformation mechanisms were studied under a uniaxial tension at three testing temperatures, i.e., -70<SUP>o</SUP>C, 25<SUP>o</SUP>C, and 150<SUP>o</SUP>C. At a testing temperature of -70<SUP>o</SUP>C, a complicated phase transformation with four stages of micromechanical deformation was identified which is associated with changes of martensite substructures. At room temperature of 25<SUP>o</SUP>C, there was no stress-induced selection process of variants of B19' phases observed. Whereas at a testing temperature of 150<SUP>o</SUP>C, there was no any phase transformation observed. It is verified that β-Nb phase, an effective stabilizer for the austenite, delays the process of martensitic transformation and relaxes the strain energy without strengthening the matrix. This new finding is important to understand the relationship between the micromechanical deformation behavior and phase transformations in the Ni<SUB>47</SUB>Ti<SUB>44</SUB>Nb<SUB>9</SUB> SMA.
Band offsets in ITO/Ga<sub>2</sub>O<sub>3</sub> heterostructures
Carey IV, Patrick H.,Ren IV, F.,Hays IV, David C.,Gila IV, B.P,Pearton IV, S.J.,Jang IV, Soohwan,Kuramata IV, Akito Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.422 No.-
<P><B>Abstract</B></P> <P>The valence band offsets in rf-sputtered Indium Tin Oxide (ITO)/single crystal β-Ga<SUB>2</SUB>O<SUB>3</SUB> (ITO/Ga<SUB>2</SUB>O<SUB>3</SUB>) heterostructures were measured with X-Ray Photoelectron Spectroscopy using the Kraut method. The bandgaps of the component materials in the heterostructure were determined by Reflection Electron Energy Loss Spectroscopy as 4.6eV for Ga<SUB>2</SUB>O<SUB>3</SUB> and 3.5eV for ITO. The valence band offset was determined to be −0.78±0.30eV, while the conduction band offset was determined to be −0.32±0.13eV. The ITO/Ga<SUB>2</SUB>O<SUB>3</SUB> system has a nested gap (type I) alignment. The use of a thin layer of ITO between a metal and the Ga<SUB>2</SUB>O<SUB>3</SUB> is an attractive approach for reducing contact resistance on Ga<SUB>2</SUB>O<SUB>3</SUB>-based power electronic devices and solar-blind photodetectors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We measured the band offsets of ITO on Ga<SUB>2</SUB>O<SUB>3</SUB>, a promising wide bandgap semiconductor for solar-blind detectors and power electronics. </LI> <LI> The band alignment is nested (type I), with a valence band offset of −0.78eV </LI> <LI> The results show the use of ITO interlayers will be beneficial to improving Ohmic contacts on Ga<SUB>2</SUB>O<SUB>3</SUB>. </LI> </UL> </P>
Removal of tar component over cracking catalysts from high temperature fuel gas
Dou, B.,Pan, W.,Ren, J.,Chen, B.,Hwang, J.,Yu, T.U. Pergamon ; Elsevier Science Ltd 2008 Energy conversion and management Vol.49 No.8
Five catalysts were evaluated for removal of tar components in high temperature fuel gas cleaning. 1-Methylnaphthalene was chosen as a model of the tar components. The NiMo catalyst having the highest surface area exhibited the highest activity of tar removal among the five catalysts. The effects of reaction temperature and space velocity on tar removal were studied in the range of 250-650<SUP>o</SUP>C and 3000-9000h<SUP>-1</SUP>, respectively. A lumped kinetic model was developed to describe the removal process. A sequential method to estimate the rate constants in the lumped kinetic model was adopted, which greatly simplifies the data treatments. Kinetic constants and activation energies were determined by a nonlinear regression program. The results showed that the predicted yields were very close to the experimental ones.