Search results for "Transit time"
showing 10 items of 13 documents
Photoplethysmography Analysis of Artery Properties in Patients with Cardiovascular Diseases
2008
In this study arterial parameters of healthy subjects were compared to those of patients with cardiovascular diseases. The photoplethysmography (PPG) measurements of blood volume pulsations have been performed. Using a novel algorithm for analysis of simultaneously measured ear and finger PPG signals, arterial parameters were evaluated in representative groups of healthy subjects and patients with cardiovascular diseases. Digital volume pulse (DVP), pulse cycle duration (T), augmentation index (AIx), reflection index (RI) and transit time of reflected wave (RTT) were evaluated in every heartbeat cycle. Correlations between the AIx and RI, T and RTT, AIx and standard deviation of AIx, RTT an…
Time Courses of Erythrocytic Oxygenation in Capillaries of the Lung: Lower and Upper Bounds on Red Cell Transit Times
1987
With the aid of a 2-dimensional computer simulation (Groebe and Thews, 1986), time courses of erythrocytic oxygen uptake in the lung were calculated.
Wearable wireless photoplethysmography sensors
2008
Wearable health monitoring sensors may support early detection of abnormal conditions and prevention of their consequences. Recent designs of three wireless photoplethysmography monitoring devices embedded in hat, glove and sock, and connected to PC or mobile phone by means of the Bluetooth technology, are described. First results of distant monitoring of heart rate and pulse wave transit time using the newly developed devices are presented.
Multimode time-dependent gyrotron equations for different time scales
2017
The work of H.K. was supported by the European Regional Development Funding of the Project No. 1.1.1.1/ 16/A/004.
On the interpretation of optical illusions.
1973
If excited by stimuli adjacent in space and time, the optical system frequently perceives illusions in the form of apparent movements. These effects may be attributed to the dynamic properties of the retinal nerve nets. On the basis of a specific psychophysical experiment the mechanism underlying the generation of optical illusions is interpreted by the methods of systems theory and its use in systems analysis is discussed. It is shown that for the perception of apparent movements the transit times of the signals in the dendrites are particularly important.
Pulse wave transit time measurements of cardiac output in septic shock patients: a comparison of the estimated continuous cardiac output system with …
2015
Pôle EAMERSCT3Hors Enjeu; Background We determined reliability of cardiac output (CO) measured by pulse wave transit time cardiac output system (esCCO system; COesCCO) vs transthoracic echocardiography (COTTE) in mechanically ventilated patients in the early phase of septic shock. A secondary objective was to assess ability of esCCO to detect change in CO after fluid infusion. Methods Mechanically ventilated patients admitted to the ICU, aged > 18 years, in sinus rhythm, in the early phase of septic shock were prospectively included. We performed fluid infusion of 500ml of crystalloid solution over 20 minutes and recorded CO by EsCCO and TTE immediately before (T0) and 5 minutes after (T1) …
Evaluation of esophageal motility and reflux in children treated for esophageal atresia with the use of combined multichannel intraluminal impedance …
2011
Abstract Background Gastroesophageal reflux (GER) and dysmotility are frequent in patients treated for esophageal atresia (EA). This aim of this study is to evaluate GER and dysmotility in young EA patients using pH–multichannel intraluminal impedance (pH-MII). Methods Fifteen patients with a mean age of 7.5 years (group 1) have been studied and compared with 15 children without congenital malformation, submitted to pH-MII for suspected GER (group 2). These latter patients serve as a control group of healthy subjects. The following impedance reflux and motility parameters have been studied on 10 standardized swallows: number of reflux episodes, mean acid clearing time, median bolus clearing…
Feasibility of cuff-free measurement of systolic and diastolic arterial blood pressure
2011
We validated a prototype cuff-free device for noninvasive estimation of blood pressure (BP). The system assumed a linear relation between BP values and the inverse of arterial blood pulse transit time, measured as time interval between the R wave on the electrocardiograph and the onset of the peripheral pulse wave on a finger plethysmogram. Thirty-three healthy subjects were analyzed at rest and during increasing stress exercise. To estimate subject-specific linear model parameters, the system was calibrated ad personam with reference to BP measures obtained by a cuff sphygmomanometer. High correlation values (R2= 0.89 and 0.78 for systolic and diastolic BP, respectively) and differences co…
Comparison of ultrasound and bone mineral density assessment of the calcaneus with different regions of interest in healthy early menopausal women.
1998
This study investigated the effect of different sized regions of interest (ROIs) on quantitative ultrasound (QUS) variables of the calcaneus. The effect on QUS of using a fixed ROI as opposed to an ROI adjusted for foot length was also assessed. Eighty Caucasian women, aged 50-57 yr (mean 53 +/- 2) who were healthy and within 0. 5-5 yr of the onset of menopause participated in this study. Using the QUS-1(trade mark) Ultrasonometer (Metra Biosystems, Mountain View, CA), we assessed broadband ultrasound attenuation ([BUA] and UBI-4, dB/MHz), the average transit time through the heel ([TTH], mus) and a multiple-factor index (UBI-4T = UBI-4/TTH, dB/[MHz. mus]). The QUS measurement results were …
The on-line isotope separation facility helios at the mainz reactor
1980
Abstract The on-line isotope separation facility HELIOS consisting of a helium-jet transport system coupled to a high transmission mass separator is described. The main characteristics of the system were determined from γ-ray measurements on neutron-rich nuclides. The transmission from the target to the skimmer is about 60%; the overall efficiency for typical fission product elements is 0.05–0.2% and the transit time for Cs is about 1.0 s.