David F Leggett - Academia.edu (original) (raw)

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Papers by David F Leggett

Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences, 2018

A healthy 51-year-old female presented with a spontaneous direct carotid-cavernous sinus fistula ... more A healthy 51-year-old female presented with a spontaneous direct carotid-cavernous sinus fistula associated with a persistent primitive trigeminal artery. She had no history of connective tissue or cerebrovascular disorders or significant head trauma. This is a rare lesion with only 18 previously reported cases. It had similar clinical presentation and imaging appearance to a high-flow direct carotid-cavernous fistula and was uncovered after successful trans-venous coil embolisation of the fistula. It therefore needs to be considered in cases of direct carotid-cavernous fistula without history of trauma. Knowledge of types of persistent primitive trigeminal artery is also important for their critical treatment implications.

The New England journal of medicine, Apr 26, 2018

Intravenous infusion of alteplase is used for thrombolysis before endovascular thrombectomy for i... more Intravenous infusion of alteplase is used for thrombolysis before endovascular thrombectomy for ischemic stroke. Tenecteplase, which is more fibrin-specific and has longer activity than alteplase, is given as a bolus and may increase the incidence of vascular reperfusion. We randomly assigned patients with ischemic stroke who had occlusion of the internal carotid, basilar, or middle cerebral artery and who were eligible to undergo thrombectomy to receive tenecteplase (at a dose of 0.25 mg per kilogram of body weight; maximum dose, 25 mg) or alteplase (at a dose of 0.9 mg per kilogram; maximum dose, 90 mg) within 4.5 hours after symptom onset. The primary outcome was reperfusion of greater than 50% of the involved ischemic territory or an absence of retrievable thrombus at the time of the initial angiographic assessment. Noninferiority of tenecteplase was tested, followed by superiority. Secondary outcomes included the modified Rankin scale score (on a scale from 0 [no neurologic def...

International journal of stroke : official journal of the International Stroke Society, Apr 1, 2017

Background and hypothesis Intravenous thrombolysis with alteplase remains standard care prior to ... more Background and hypothesis Intravenous thrombolysis with alteplase remains standard care prior to thrombectomy for eligible patients within 4.5 h of ischemic stroke onset. However, alteplase only succeeds in reperfusing large vessel arterial occlusion prior to thrombectomy in a minority of patients. We hypothesized that tenecteplase is non-inferior to alteplase in achieving reperfusion at initial angiogram, when administered within 4.5 h of ischemic stroke onset, in patients planned to undergo endovascular therapy. Study design EXTEND-IA TNK is an investigator-initiated, phase II, multicenter, prospective, randomized, open-label, blinded-endpoint non-inferiority study. Eligibility requires a diagnosis of ischemic stroke within 4.5 h of stroke onset, pre-stroke modified Rankin Scale≤3 (no upper age limit), large vessel occlusion (internal carotid, basilar, or middle cerebral artery) on multimodal computed tomography and absence of contraindications to intravenous thrombolysis. Patient...

Public Money Manage, 1995

Chemical Engineering, 2000

17th Atmospheric Flight Mechanics Conference, 1990

16th Atmospheric Flight Mechanics Conference, 1989

Biennial Flight Test Conference, 1994

Proceedings of the IEEE 1991 National Aerospace and Electronics Conference NAECON 1991, 1991

The Variable Stability In-Flight Simulator Test Aircraft (VISTA) is the next generation US in-fli... more The Variable Stability In-Flight Simulator Test Aircraft (VISTA) is the next generation US in-flight simulator for high-performance aircraft currently being developed by the US Air Force. VISTA is an F-16D in which the cockpit environment, feel, and flying characteristics can be changed to match a wide array of aircraft. While VISTA can simulate a wide range of dynamics, its capabilities are subject to certain practical limitations due to aircraft mass and inertia, available control power, actuator bandwidth, computational delays, structural modes, etc.

AIAA Guidance, Navigation, and Control Conference and Exhibit, 2000

A quaternion-based attitude control system is developed for the X-33 in the ascent flight phase. ... more A quaternion-based attitude control system is developed for the X-33 in the ascent flight phase. A nonlinear control law commands body-axis rotation rates that align the angular velocity vector with an Euler-axis defining the axis of rotation that takes the body-axis system into ...

Modeling and Simulation Technologies Conference, 1997

Journal of Guidance, Control, and Dynamics, 2002

Journal of Guidance, Control, and Dynamics, 2004

ABSTRACT The need for good aircraft handling qualities has been apparent since the days of the Wr... more ABSTRACT The need for good aircraft handling qualities has been apparent since the days of the Wright Flyer. In the past decade, there has been a perception that this need has lessened as advanced concepts have evolved, in parallel with acquisition reform. The former has led those who are unfamiliar with the field of handling qualities to conclude that quantitative requirements are not necessary, as the latter has resulted in the elimination of the military specifications for handling qualities. This paper reviews the evolution of handling qualities and their specifications. It presents some ongoing challenges in the field to illustrate that handling qualities are still a critical issue for future aircraft.

IEEE Aerospace and Electronic Systems Magazine, 2000

The STOL maneuver technology demonstrator (S/MTD) simulation is a high-fidelity, pilot-in-the-loo... more The STOL maneuver technology demonstrator (S/MTD) simulation is a high-fidelity, pilot-in-the-loop motion base simulation. The simulation was used to evaluate takeoff, landing, and air-to-air tasks before the first flight of the S/MTD aircraft to improve aircraft flying qualities, conduct engineering research, and ensure safety of flight. 208 hours of pilot-in-the-loop evaluations were conducted. A description is given of the simulation

Thermochim Acta, 1996

Carbon beds containing organics, in contact with air, exhibit potential for thermal runaway. To a... more Carbon beds containing organics, in contact with air, exhibit potential for thermal runaway. To accurately define the spontaneous oxidative thermokinetics, appropriate calorimetric techniques are required. A stopped-flow heat-flux calorimetry for oxidative heat-rate measurement is presented in conjunction with the results generated by accelerating rate calorimetry. The stopped-flow method eliminates many experimental uncertainties encountered with the conventional continuous gassparging method, and generates accurate and reproducible heat-rate data in a single test run. This technique is particularly useful in solid oxidation systems containing volatile organics.