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BACKGROUND: The assessment of return of function within dysfunctional myocardium after acute myocardial infarction (MI) using contractile reserve has been primarily qualitative. Magnetic resonance (MR) myocardial tagging is a novel noninvasive method that measures intramyocardial function. We hypothesized that MR tagging could be used to quantify the intramyocardial response to low-dose dobutamine and relate this response to return of function in patients after first MI. METHODS AND RESULTS: Twenty patients with a first reperfused MI (age, 53+/-12 years; 16 male; 11 inferior MIs) were studied. Patients underwent breath-hold MR-tagged short-axis imaging on day 4+/-2 after MI at baseline and during dobutamine infusion at 5 and 10 microg x kg(-1) x min(-1). At 8+/-1 weeks after MI, patients returned for a follow-up MR tagging study without dobutamine. Quantification of percent intramyocardial circumferential segment shortening (%S) was performed. Low-dose dobutamine MRI was well tolerated. Overall, mean %S was 15+/-11% at baseline (n=227 segments), increased to 16+/-10% at 5 microg x kg(-1) x min(-1) dobutamine (P=NS), 21+/-10% at peak (P<0.0001 versus baseline and 5 microg x kg(-1) x min(-1), and 18+/-10% at 8 weeks (P<0.004 versus baseline and peak). The increase in %S with peak dobutamine was greater in dysfunctional myocardium (103 segments, +9+/-10%) than in normal tissue (124 segments, +4+/-12%, P<0.0001). In dysfunctional regions, %S also increased from 6+/-7% at baseline to 14+/-10% at 8 weeks after MI (P<0.0001). In dysfunctional regions that responded normally to peak dobutamine (> or =5% increase in %S), the increase in %S from baseline to 8 weeks after MI (+9+/-9%) was greater than in those regions that did not respond normally (+5+/-9%, P<0.04). Midmyocardial and subepicardial response to dobutamine were predictive of functional recovery, but the subendocardial response was not. CONCLUSIONS: The response of intramyocardial function to low-dose dobutamine after reperfused MI can be quantified with MR tagging. Dysfunctional tissue after MI demonstrates a larger contractile response to dobutamine than normal myocardium. A normal increase in shortening elicited by dobutamine within dysfunctional midwall and subepicardium predicts greater functional recovery at 8 weeks after MI, but the response within the subendocardium is not predictive. 相似文献
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In a previous letter, a dislocation model of planar-silicon-transistor burst noise was proposed. The burst statistical parameters have been measured and their dependence on bias is in good agreement with the model. 相似文献
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This paper discusses the process of the generation of hot points in reverse biased p?n diodes. In this work we use a simple lumped thermal model of the diode. The stability of the nearly uniform distribution of the current through the junction of the diode is analysed. This analysis determines, for every diode, the maximum value of the current under which the junction will be free of current constriction, or hot points. It is concluded that, for diodes which are small enough, a hot point cannot appear. Nevertheless, if a nearly ideal voltage generator is used to drive the diode, a thermal instability of the whole junction can appear. 相似文献
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Diego?VázquezEmail author Gloria?Huertas áfrica?Luque Manuel?J.?Barragán Gildas?Leger Adoración?Rueda José?L.?Huertas 《Journal of Electronic Testing》2005,21(3):221-232
This paper presents a method for extracting, in the digital domain, the main characteristic parameters of an analog sine-wave signal. It is based on a double-modulation, square-wave and sigma-delta, together with a simple Digital Processing Algorithm. It leads to an efficient and robust approach very suitable for BIST applications. In this line, some considerations for on-chip implementation are addressed together with simulation results that validate the feasibility of the proposed approach.Diego Vázquez was born in El Coronil, Sevilla, Spain, in 1966. He received the Licenciado en Física degree in 1989 and the Doctor en Ciencias Físicas degree in 1995, both from the University of Sevilla, Spain. Since 1990, he has been with the Departamento de Electrónica y Electromagnetismo, University of Sevilla, where he is a Associate Professor, and also with the Instituto de Microelectrónica de Sevilla, Centro Nacional de Microelectrónica (IMSE-CNM-CSIC), Sevilla, Spain. He has published about 100 papers in international journals, books and major conferences. In 1992 he won the Best Paper Award of the 10th IEEE VLSI Test Symposium. His research interests are in the fields of design, fault tolerance, test, and design for testability of analog and mixed-signal circuits.Gloria Huertas was born in Sevilla, Spain, in 1974. She received the Licenciado en Física degree in 1997 and the Ph.D. in 2004, both from the University of Sevilla, Spain. Since then, she has been with the Departamento de Electrónica y Electromagnetismo, University of Sevilla, where she is Assistant Professor, and also with the Instituto de Microelectrónica de Sevilla, Centro Nacional de Microelectrónica (IMSE-CNM-CSIC), Sevilla, Spain. Her research focuses on designing electronic mixed-signal circuits and systems including techniques for testability.África Luque was born in Zamora (Spain) in 1977. She received the Licenciado en Física degree in 2000 from the University of Sevilla, Sevilla, Spain. She is with the Departamento de Electrónica y Electromagnetismo, University of Sevilla, and also with the Instituto de Microelectrónica de Sevilla, Centro Nacional de Microelectrónica (IMSE-CNM-CSIC), Sevilla, Spain, where she is currently pursuing the Ph.D. degree. Her research focuses on the design and test of mixed-signal circuits including Silicon-On-Insulator technologies.Manuel J. Barragan was born in Sevilla, Spain, in 1980. He received the Licenciado en Física degree in 2003 from the University of Sevilla, Sevilla, Spain. He is currently pursuing the Ph.D. degree from the Instituto de Microelectrónica de Sevilla (IMSE, CNM) on the topics of test and design for testability of analog and mixed-signal circuits.Gildas Leger was born in St. Brieuc, Côtes dArmor, France, in 1976. He received the Ingénieur en Physique degree in 1999 from the National Institute of Applied Sciences (INSA) of Rennes, France.He is currently pursuing the Ph.D. degree from the Instituto de Microelectrónica de Sevilla (IMSE, CNM). His research focuses on designing electronic mixed-signal circuits and systems including techniques for testability, specially in the domain of analog to digital conversion.Adoración Rueda joined the Department of Electronics and Electromagnetism at the University of Seville in 1976 as Assistant Professor, and obtained the Ph.D. degree in 1982. From 1984 to 1996 she was Associate Professor in that Department, where now holds the position of Full Professor in Electronics. In 1989 she became researcher at the Department of Analog Design of the National Microelectronics Center (CNM), now Institute of Microelectronics at Seville (IMSE).She has participated in several research projects financed by the Spanish CICYT and by different programs of the European Community. She has published about 135 papers in international journals, books and major conferences. In 1992 she won the Best Paper Award of the 10th IEEE VLSI Test Symposium. Her research interests are currently focused on the topics of Design and Test of Analog and Mixed-signal Circuits, Behavioral Modeling of Mixed-signal Circuits, and development of CAD tools.Jose Luis Huertas received the Licenciado en Física degree nd the Doctor en Ciencias Físicas degrees in 1969 and 1973, respectively, both from the University of Sevilla, Spain.From 1970 to 1971, he was with the Philips International Institute, Eindhoven, The Netherlands, as a postgraduate student. Since 1971, he has been with the Departamento de Electrónica y Electromagnetismo, University of Sevilla, Spain, where he is a Full Professor. He is also the Director of the Instituto de Microelectrónica de Sevilla, Centro Nacional de Microelectrónica de Sevilla, Seville, Spain. His current interests include the design and testing of analog/digital integrated circuits, computer-aided IC analysis and design, fuzzy logic, nonlinear microelectronics, and neural networks. 相似文献
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Tania Castaño Dr. Huanchen Wang Dr. Nuria E. Campillo Dr. Sara Ballester Dr. Coral González‐García Javier Hernández Concepción Pérez Dr. Jimena Cuenca Dr. Ana Pérez‐Castillo Prof. Ana Martínez Prof. Oscar Huertas José Luis Gelpí Prof. F. Javier Luque Prof. Hengming Ke Prof. Carmen Gil Dr. 《ChemMedChem》2009,4(5):866-876
PDE7 inhibitors regulate pro‐inflammatory and immune T‐cell functions, and are a potentially novel class of drugs particularly useful for treatment of a wide variety of immune and inflammatory disorders. Structural optimization of thioxoquinazoline derivatives led to new compounds with very interesting profiles as PDE7 or PDE7/PDE4 dual inhibitors, which may be further developed as new drugs for inflammatory and neurological diseases.