Endovascular repair of blunt traumatic thoracic aortic injuries: seven-year single-center experience.
ABSTRACT Thoracic endovascular aortic repair (TEVAR) for acute blunt thoracic aortic injury has good early and mid-term results.
Single-center retrospective 7-year review from January 2001 to December 2008.
Urban tertiary care hospital.
Twenty-four consecutive patients with acute blunt thoracic aortic injury treated with TEVAR.
Procedure-related mortality, stroke, or paraplegia; injury severity score; and complications.
Among the 24 treated patients (mean age, 41 years; range, 20-71 years), the mean injury severity score was 43 (range, 25-66). Thoracic endovascular aortic repair was successful in treating the aortic injury in all patients and there were no instances of procedure-related death, stroke, or paraplegia. Access to the aorta was obtained through an open femoral/iliac approach (n = 7) or an entirely percutaneous groin approach (n = 17). Systemic heparin was not used in 84% of cases. Two access complications (8%) occurred, requiring an iliofemoral bypass in one patient and a thrombectomy in another. One patient required secondary intervention for device collapse, which was treated successfully with repeat endografting. There have been no delayed device failures or complications among the entire cohort at mid-term follow-up.
Thoracic endovascular aortic repair, via a percutaneous groin approach and without systemic anticoagulation, for blunt thoracic aortic injury can be performed safely with low periprocedural mortality and morbidity.
Conference Paper: Improved COMFETs with fast switching speed and high-current capability[Show abstract] [Hide abstract]
ABSTRACT: Conventional vertical power MOSFETs are limited at high voltages (>500V) by the appreciable resistance of their epitaxial drain region. In a new MOS-gate controlled device called a COMFET (or an IGR), this limitation is overcome by modulating the conductivity of the resistive drain region, thereby reducing the on-resistance of the device by a factor of at least 10. However, the device previously described is slow in turn-off, having a fall time in the range 8 to 40 µs. The purpose of our present work has been to reduce the fall time significantly and to increase the latching current level of the COMFET, while retaining its desirable features. By modification of the epitaxial structure and addition of recombination centers, we have achieved fall times as low as 0.1 µs and latching currents as high as 50 A, while retaining on-resistance values < 0.2 ohms for a 0.09 cm<sup>2</sup>chip area. The techniques used for the introduction of recombination centers include electron, gamma-ray, and neutron irradiation, as well as heavy metal doping. For a series of COMFETs (with forward blocking voltage capabilities of 400-600V), the fall time can be reduced by more than one order of magnitude with a penalty of less than a 20% increase in on-resistance.Electron Devices Meeting, 1983 International; 02/1983
Conference Paper: A pseudomorphic GaAs/GaInAs/AlGaAs SISFET[Show abstract] [Hide abstract]
ABSTRACT: The authors report a pseudomorphic semiconductor-insulator-semiconductor field-effect transistor (PM-SISFET) that uses a thin layer of undoped GaInAs instead of GaAs as the channel-forming layer. The device consists of an undoped AlGaAs barrier layer, a heavily doped n-type GaAs gate, and an upper GaInAs contact layer. With this structure, the device has a naturally negative threshold voltage. The structures were grown by molecular beam epitaxy. The devices were fabricated using, as for conventional GaAs SISFETs, self-aligned ion implantation and rapid thermal annealing (RTA). High-resolution photoluminescence spectra at 4.2 K for both the as-grown layer and after RTA have a FWHM (full width at half-maximum) of 3.1 MeV for a 120-Å-thick GaInAs channel layer with an In content of about 12%. These measurements indicate that no structural degradation of the strained layer occurred during annealing. To compare performance, the authors also grew and processed conventional GaAs/AlGaAs/n<sup>+</sup>-GaAs SISFETs. At 300 K, the 1-μm-gate-length devices showed transconductances and drain currents in excess of 270 mS/mm and 250 mA/mm, respectively, for PM-SISFETs compared to 240 mS/mm and 200 mA/mm, respectively, for similar conventional SISFETsHigh Speed Semiconductor Devices and Circuits, 1989. Proceedings., IEEE/Cornell Conference on Advanced Concepts in; 09/1989
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ABSTRACT: We began this article with brief overview of the theoretical and methodological shortcomings that led to the decades-old myth of attentional deficit as central to mental retardation. We presented a reanalysis of the available data and suggested that no empirical evidence supports any relationship between attention deficits and mental retardation per se, although available data is certainly not definitive with regard to this question. Furthermore, we suggested that certain attentional deficits may be associated with specific etiological groups. This review of research on attention among persons with mental retardation provided the context for a review of historical landmarks and contemporary innovations and issues in the developmental approach to the study of persons with mental retardation. This framework is clearly not problem-free, but its contributions to increased precision and sophistication in theory, methodology, and interpretation are essential to the study of persons with mental retardation. As compared to other approaches, the developmental one is limiting as it generally necessitates the use of more resources in the study of smaller groups, but is necessary for increased accuracy and precision in empirical findings. Greater awareness of developmental issues will inevitably lead to an increasingly heuristic and collaborative approach to research in which studies will be designed to complement one onother. Ultimately, the products of these collaborations will provide information that is optimally helpful to persons with mental retardation, their families, and those who work with them.