Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"Blood flow velocity"”.
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Effect of head elevation on intracranial blood flow velocity following acute ischemic stroke
… elevation on middle cerebral artery (MCA) mean flow velocity (MFV) in a convenience sample of 20 patients presenting with acute ischemic stroke. Transcranial Doppler (TCD) sonography mounted by head frame was used to measure MCA MFV. Patients were on average 59.5 years of age (SD = 15.4), with a …
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The use of a neural network to recognize placental insufficiency from blood flow velocity waveforms in the umbilical cord
… is based on measuring the umbilical arterial blood flow velocity waveforms from one site of the cord. There is an ongoing debate on the predictive value of Doppler measurements in the evaluation of the foetal condition. The aim of this thesis is to investigate the use ofa neural network to …
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Doppler ultrasound technique used to determine the blood flow viscosity in the middle cerebral artery of a canine animal model
The cerebral blood flow velocity in the middle cerebral artery of an canine animal model was measured using the Doppler Ultrasound technique. A transducer was designed with a 20 MHz piezoelectric crystal and used for the application. An in vitro calibration system was designed and machined for the …
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Mathematical modeling of foetal arterial blood flow
… various haemodynamic viriables on common Doppler blood flow velocity waveform indices. The foetal model consists of an number of vascular compartments, cascaded together using electrical transmission line analogies.
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Transcranial Doppler sonography: a new noninvasive method for measuring toxicant-induced alterations in cerebral blood flow
… dog to noninvasively measure changes in cerebral blood flow (CBF) resulting from a low-level exposure to the commonly used pyrethroid insecticide deltamethrin. Deltamethrin has previously been shown to increase CBF in rats as determined by other techniques. In this experiment, deltamethrin was …
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An embedded device for real-time noninvasive intracranial pressure estimation
… to noninvasive ICP estimation from cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) waveforms, I have implemented the algorithm on an embedded device (LPC4337 microcontroller) that can produce real-time estimates of ICP from noninvasively-obtained ABP and CBFV …
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Arterial blood pressure estimation using ultrasound technology and transmission line arterial model
… disease. This work details how to obtain the blood flow and pulse pressure waveforms using ultrasound transducers. Two transducers, one for imaging and one for Doppler, can be used together to derive these waveforms from distension and blood flow velocity measurements. Unfortunately, the only …
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Pressure, Compliance, and Autoregulation Studies in Intracranial Dynamics
… between intracranial pressure and cerebral blood flow velocity pulse amplitudes. Finally, a dependency between craniospinal compliance and the frequency at which it is calculated was discovered, and deep learning models showed potential for predicting intracranial pressure non-invasively. …
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An electronically steered, wearable transcranial doppler ultrasound system
… (TCD) ultrasound system to measure cerebral blood flow velocity (CBFV) at the middle cerebral artery (MCA). TCD sonography has been clinically indicated in a variety of neurovascular diagnostic applications. Acceptance of conventional TCD methods, however, has been primarily impeded by …
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A pseudo-Bayesian model-based approach for noninvasive intracranial pressure estimation
… of the cerebral vasculature relates arterial blood pressure with cerebral blood flow velocity. The model is solved for a range of physiologically plausible ICP values, and the resulting residual errors are transformed into likelihoods for each candidate ICP. The likelihoods are combined with a …
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Machine Learning Applications for Time Series Data: Motor Anomaly Detection and Mean Arterial Blood Pressure Estimation
… Detection, and (2) Estimation of Mean Arterial Blood Pressure (MAP) from ultrasound measurements. In the first application, we explore different algorithms for detecting anomalous fan motor operation on a small microcontroller unit (MCU). Results show that a CNN model can maintain 99% accuracy …
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Modeling the Arterial System to Improve Ultrasound Measurements of Hemodynamic Parameters
… disease (CVD) risk is one’s Arterial Blood Pressure (ABP). Clinicians use a radial arterial catheter to measure ABP in an intensive care unit (ICU). Although this method is considered the gold standard, its invasive nature makes it undesirable and inaccessible outside an ICU. One …
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Mechanisms of Control of Blood Flow in the Forelimb of Sheep
… about the factors involved in the control of blood flow, the cellular mechanisms of their action are poorly understood. This study investigated the mechanisms of norepinephrine, epinephrine, isoproterenol, and acetylcholine.</p> <p>First, in a constant pressure/variable flow preparation we …
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A spectral approach for noninvasive estimation of intracranial pressure
… spectral approach to estimate ICP from arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) measurements. To support such ICP estimation, we developed a data acquisition system to archive high quality, high resolution waveforms from various bedside monitoring devices along a …
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Effect of nicotine and alcohol exposure in utero on vascular intima medial thickness, endothelial function, and the development of cardiometabolic risk factors in children in a low-income setting.
… subscapular and triceps skinfold thickness, blood pressure, lipid profiles and non-fasting blood glucose concentrations were measured. Mothers were interviewed to obtain data regarding maternal smoking and alcohol use, health status, and demographic characteristics. In phase II, subclinical …
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Do abnormalities in dynamic cerebral auto-regulation underlie the pathophysiological processes behind syncope in older people?
… for cardiac BRS, arterial stiffness, cerebral blood flow velocity (CBFV) or dCA in either study. HUT both studies: falls in BP, CO2 and CBFV, increases in HR, and fall in ARI amongst symptomatic subjects prior to the end of HUT (maximum duration or symptom onset) compared to pre-HUT values. PPH …
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The Effect of Compression Stockings and Foot Exercises on Venous Blood Velocity
… stockings and foot exercise on venous blood velocity, an exploratory pilot study was conducted. An additional purpose of the investigation was to evaluate the noninvasive doppler ultrasonic flowmeter as a data collecting tool.</p> <p>Fourteen volunteer female subjects, ages 40 to 80, …
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