Search results for "VELOCITY"
showing 10 items of 881 documents
Effect of hyperthermia on tumor blood flow.
1984
Differences in blood perfusion rates between tumors and normal tissue can be utilized to selectively heat many solid tumors. Blood flow in normal tissues is considerably increased at temperatures commonly applied during localized hyperthermia. In contrast, tumor blood flow may respond to localized heat typically in two different blood flow patterns: Flow may either decrease continuously with increasing exposure time and/or temperature or flow may exhibit a transient increase followed by a decline. A decrease in blood flow at high thermal doses can be observed in most of the tumors, whereas an increase in flow at low thermal doses seems to occur less frequently. The inhibition of blood flow …
Analyzing the electrophysiological effects of local epicardial temperature in experimental studies with isolated hearts
2008
As a result of their modulating effects upon myocardial electrophysiology, both hypo- and hyperthermia can be used to study the mechanisms that generate or sustain cardiac arrhythmias. The present study describes an original electrode developed with thick-film technology and capable of controlling regional temperature variations in the epicardium while simultaneously registering its electrical activity. In this way, it is possible to measure electrophysiological parameters of the heart at different temperatures. The results obtained with this device in a study with isolated and perfused rabbit hearts are reported. An exploration has been made of the effects of local temperature changes upon…
Probing the low-temperature chemistry of ethanol via the addition of dimethyl ether
2018
Considering the importance of ethanol (EtOH) as an engine fuel and a key component of surrogate fuels, the further understanding of its auto-ignition and oxidation characteristics at engine-relevant conditions (high pressures and low temperatures) is still necessary. However, it remains difficult to measure ignition delay times for ethanol at temperatures below 850 K with currently available facilities including shock tube and rapid compression machine due to its low reactivity. Considering the success of our recent study of toluene oxidation under similar conditions [38], dimethyl ether (DME) has been selected as a radical initiator to explore the low-temperature reactivity of ethanol. In …
An Analysis of the Time-Varying Behavior of the Equilibrium Velocity of Money in the Euro Area
2020
Recent developments in inflation and M3 velocity in the euro area have raised serious doubts about the reliability of M3 growth as a pillar of the ECB’s monetary policy strategy. We develop a very flexible and comprehensive state-space framework for modeling the velocity of circulation. Our specification allows for the estimation of different autoregressive alternatives and includes control instruments, whose coefficients can be set up either common or idiosyncratic. This is particularly useful to detect asymmetries in the reaction among countries to common shocks. Our findings first suggest that the downward trend of M3 velocity is mainly explained by the evolution of permanent income, pro…
Physiological responses of running intermittent exercises
2012
The aims of the present work were to analyze the physiological responses during intermittent exercise and to determine; i) an field test to assess the maximal aerobic velocity (MAV) for intermittent exercise; ii) the type of intermittent exercise could elicit maximal oxygen uptake (VO2max); iii) the physiological and neuromuscular factors that could limit intermittent exercise duration.The first study demonstrated that the MAV (MAV45-15) reached at the end of an incremental intermittent (45s run/ 15s rest) field test (45-15FIT) was relevant to elicit a high percentage of VO2max during a 30s-30s intermittent training session. The second and third studies demonstrated that intermittent exerci…
Transcranial Doppler and Cortical Microcirculation at Increased Intracranial Pressure and during the Cushing Response
1995
The effect of increased intracranial pressure on the flow velocity of the basilar artery was measured with transcranial ultrasonic Doppler in New Zealand White rabbits under alpha-chloralose anesthesia and artificial respiration. Laser Doppler flowmetry served to study changes of the cortical microcirculation. The results confirm a high inverse correlation of the diastolic flow velocity, the pulsatility index, and the resistance index with the cerebral perfusion pressure (CPP). During acute intracranial hypertension, however, these parameters do not show a good correlation with the local cortical blood flow. The absence of a correlation was evident over a wide CPP range down to values of 35…
Update on topical carbonic anhydrase inhibitors
2001
Topical carbonic anhydrase inhibitors are a novel addition to the armamentarium of medical glaucoma treatment; dorzolamide has been available since 1995 and brinzolamide since 1998. They lower intraocular pressure by inhibiting carbonic anhydrase, a key enzyme for aqueous humor formation. Intraocular pressure-lowering activity of the substances appears to be the same and is similar to that of most other agents, but it does not reach the activity of the unselective beta-blocker timolol or the prostaglandin latanoprost. On concomitant treatment, additivity is reached with all other topical agents. A possible improvement of blood flow may offer an additional benefit, but its significance for t…
Does transvaginal color Doppler sonography differentiate between developing and involuting ectopic pregnancies?
1995
The objective of this study was to assess the addition of transvaginal color Doppler imaging to transvaginal ultrasonography and beta-human chorionic gonadotropin values to differentiate between developin and involuting ectopic pregnancies. Forty surgically confirmed ectopic pregnancies were classified into developing or involuting according to histopathologic findings. Results were compared retrospectively with the plasma beta-human chorionic gonadotropin values as well as the resistive index and pulsatility index obtained in corpora lutea and peritrophoblastic flow in serial examinations. Student's t-test was used for comparison of means. Logistic regression analysis was applied to predic…
Effect of pistachio on brachial artery diameter and flow-mediated dilatation: A systematic review and meta-analysis of randomized, controlled-feeding…
2017
Background: Results of previous clinical trials evaluating the effect of pistachio supplementation on endothelial reactivity (ER) are controversial. Aims: We aimed to assess the impact of pistachio on ER through systematic review of literature and meta-analysis of available randomized, controlled-feeding clinical studies (RCTs). Methods: The literature search included SCOPUS, PubMed-Medline, ISI Web of Science and Google Scholar databases up to 1st August 2017 to identify RCTs investigating the impact of pistachio on ER. Two independent reviewers extracted data on study characteristics, methods and outcomes. Overall, the impact of pistachio on ER was reported in 4 trials. Results: The meta-…
Three-Dimensional Kinematics during the Take-Off Phase in Competitive Long Jumping
2013
The purpose of the present study was to identify the relationships among selected kinematic variables that affect the take-off phase and performance in elite jumpers. The jump distance was found to be related to: I) the athlete's approach speed before the instant of touch down; and ii) the exchange in spatial velocity components at take-off, which results in a gain in maximum vertical velocity of the centre of mass (CM), favoured by the use of an optimum touch-down angle of the take-off leg, an active landing of the foot at touch-down, and a motion of the take-off leg during the compression phase that helps to manage the loss of horizontal velocity. Nonetheless, the results show that an ad…