No description available.

No description available.

Central motor conduction was assessed as a predictor of mortality and functional outcome in a longitudinal study of 118 patients with first-ever stroke. Investigations commenced 12-72 hours after stroke and were repeated up to death or 12 months. The results were compared with normal data, validated assessments of motor function, detailed neurological examinations and CT scans. Responses were recorded in the surface electromyogram from proximal and distal muscles of both upper limbs following percutaneous electromagnetic stimulation of the motor cortex (muscles contracted) and spinal motor roots (muscles relaxed). Central Motor Conduction Time (CMCT) was estimated by subtracting the latencies of spinal root evoked responses from those of cortical evoked responses. The durations and thresholds of the responses were recorded. Investigations 12-72 hours after stroke identified patients with 1) normal CIVICT, 2) delayed CIVICT, and 3) absent responses. Sequential investigations up to 12 months after stroke revealed 1) CIVICT may remain unchanged, 2) delayed CIVICT may become normal 3) responses may reappear with shortened duration, with delayed or normal CIVICT, 4) responses were lost if the stroke extended, 5) initially high thresholds to stimulation decreased. Absent responses 12-72 hours after stroke initially correlated with reduced power, hand dexterity and functional ability, and with large infarctions, mass effect and cortical lesions on CT scans. Normal CIVICT correlated with a high probability of survival and significantly better functional recovery at 12 months. Absent responses correlated with a high probability of stroke-related death. Survivors had poor outcome for muscle power, hand dexterity, activities of daily living, functional outcome and duration of stay in hospital. Results from the thenar muscles alone provided accurate prognostic information. If results from all the muscles were considered and the test repeated seven days after the first assessment, the sensitivity of the test increased. Electromagnetic stimulation is a safe prognostic investigation that is complementary to clinical examination and imaging patients with stroke.

No description available.

Research Doctorate - Doctor of Philosophy (PhD) / Mechanical structures encounter vibration in response to environmental conditions and dynamic loads. In most circumstances, vibration contributes to mechanical fatigue which can eventually lead to catastrophic failure. Consequently, vibration control is a necessity for prolonging the operational life of structures. Piezoelectric and electromagnetic transducers have been used for control of vibration for many years. They normally sense mechanical vibration and generate an opposing vibration through another piezoelectric and electromagnetic transducer. This is usually referred to as active feedback vibration control. Another vibration control strategy senses and actuates simultaneously through an appropriately designed electrical impedance which is connected to the terminals of a single transducer. This technique requires no additional sensor, has improved robustness and stability, and a similar feedback structure compared to active feedback vibration control. The objective of this thesis is to develop new vibration control techniques by expanding on both the previously mentioned strategies. The first part of this thesis considers connecting an electrical impedance to a piezoelectric transducer to control vibration. This part reinforces that this vibration control strategy can be modelled as a variation of active feedback vibration control whereby the impedance parameterises the effective controller. A series of new vibration controllers are then presented. Applying the knowledge gained in the first part of this thesis, the second part considers replacing the piezoelectric transducer with an electromagnetic transducer. Although the underlying dynamics and physical properties of the transducers are different, the feedback structures are remarkably similar to that of active feedback vibration control. A number of new vibration control strategies are proposed for a variety of mechanical systems. Throughout the thesis, theoretical ideas and concepts are experimentally compared and validated on simple mechanical apparatuses to evaluate their vibration control performance.

Thesis (Ph. D.)--Ohio University, March, 1993. / Title from PDF t.p.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 2, 2008) Includes bibliographical references.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Dec. 3, 2007). PDF text: xi, 217 p. : ill. ; 81 Mb. UMI publication number: AAT 3263487. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.S.)--Ohio University, June, 1987. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, August, 1988. / Title from PDF t.p.