Flow-mediated dilation (FMD) is used as a surrogate marker for endothelial function, a subclinical indicator of coronary artery disease (CAD) and for that reason; FMD is commonly used to compare endothelial function across groups differing in age and number and/or type of CAD risk factors. The traditional calculation of FMD involves arterial diameter prior to cuff inflation and then peak arterial diameter following cuff release. Generally, arterial response during cuff inflation is not taken into consideration. The aims of the present study were to determine 1) if there were differences in brachial artery response, more specifically vasoconstriction, during cuff inflation in a diverse population of subjects, 2) if variability existed, the resulting impact on the calculation of traditional FMD, and 3) if arterial stiffness was a physiological determinant in this process. A total of 84 subjects, varying in age (18-62 years) and CAD risk factor profiles were studied. Low flow-mediated constriction (L-FMC), during cuff inflation, traditional FMD, and modified FMD, which accounts for L-FMC, were calculated to investigate brachial artery response during all three stages of the FMD measurement. Subjects ≥ 50 years old had lower FMD response compared with those ≤ 35 years old but only the modified FMD was statistically significant. The same effect was seen when comparing healthy subjects to those with multiple risk factors for CAD; there was an attenuated FMD response that only reached statistical significance with modified FMD. L-FMC was modestly but significantly associated with FMD. L-FMC was weakly but positively correlated with brachial pulse wave velocity (PWV). Our results indicate that modified FMD, which takes into consideration brachial response to cuff inflation, may be a more sensitive indicator of endothelial dysfunction and that arterial stiffening may be a physiological determinant in this process. / text

In the present work we develop a unified way of looking at normed spaces of analytic functions (NSAF's) and their embedding into the Frechet space of analytic functions on a general domain, by requiring only that the embedding map is bounded. This is a succinct definition of NSAF and derive from it a list of interesting properties. For example Proposition 4.4 describes the behavior of point evaluations and Proposition 4.6 part (i) gives a general sufficient condition for a NSAF to be a Banach space, which as far as we know, are new results. Also, Proposition 4.5, parts (ii) and (iii) of Proposition 4.6 and Proposition 4.7 are results, which are slight generalizations of fairly standard results, which show up elsewhere in a more specific setting. Some of the facts about NSAF's are stated and proven in a more general context. In particular, a significant part of the material is dedicated to the normed space of continuous functions on a metric space. On the other hand, we provide the necessary background on differential geometry and complex analysis, which further determine the peculiarities in the context of spaces of analytic functions. At the end we illustrate our results on two specific examples of NSAF's, namely the Bergman and the Bloch Spaces over a general domain in Cd. We give a new proof of the reflexivity of the Bergman Space Ap(G, μ) for the case p>1 and of the Schur property of A1(G, μ). We also give new proofs for the equivalences of some of the definitions of the Bloch functions.

The vascular endothelium is a single layer of cells that lines the interior surface of our blood vessels. The endothelium plays a key role in vasoprotection and vasoregulation and its proper function is therefore essential to the maintenance of vascular health. The endothelial cells respond to the frictional force (shear stress (SS)) that occurs with an increase in blood flow. As a response, vasoactive substances are released, causing the artery to dilate, this is termed flow-mediated dilation (FMD). Endothelial cell function can be assessed by measuring the vasodilatory response to an increase in SS. Currently however, our ability to interpret the results of FMD assessment in order to make accurate judgements regarding arterial health is hindered by an incomplete understanding of the “dose-response” relationship between SS and FMD. The dose-response relationship is characterized by 1) the SS stimulus required to elicit an FMD response (threshold), 2) the magnitude of dilation for a given increase in SS (the slope of the SS-FMD relationship), and 3) the point at which further increases in SS no longer elicit dilation (the ceiling). The primary purpose of the current study was to characterize the magnitude and day-to-day variability of the parameters described above. N=20 males (mean 22-years). Brachial artery diameter (BAD) and blood velocity (BV) were assessed with echo and Doppler ultrasound. SS was estimated as shear rate (SR=BV/BAD). Subjects performed 2 incremental handgrip exercise trials on two separate visits (V1 and V2). CV=co-efficient of variation. The SS-FMD relationship was characterized by a shallow slope followed by an inflection point (threshold (T1)) and a steeper slope (pre vs. post T1 slope p=0.002). There was no difference between V1 vs. V2 in the SR-FMD slope or threshold (p>0.05), but there was considerable within-subject variability in the SR-FMD parameters: pre-T1 slope CV = 47.0 ± 33.1%; post-T1 slope CV = 55.3 ± 40.7%; T1 CV = 25.6 ± 6.3%. In conclusion, %FMD did not plateau with increasing SR, therefore no ceiling was identified. The inflection in slope may indicate the involvement of different or additional vasodilator mechanisms post-threshold. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2011-09-15 20:17:11.582

In the present work we develop a unified way of looking at normed spaces of analytic functions (NSAF's) and their embedding into the Frechet space of analytic functions on a general domain, by requiring only that the embedding map is bounded. This is a succinct definition of NSAF and derive from it a list of interesting properties. For example Proposition 4.4 describes the behavior of point evaluations and Proposition 4.6 part (i) gives a general sufficient condition for a NSAF to be a Banach space, which as far as we know, are new results. Also, Proposition 4.5, parts (ii) and (iii) of Proposition 4.6 and Proposition 4.7 are results, which are slight generalizations of fairly standard results, which show up elsewhere in a more specific setting. Some of the facts about NSAF's are stated and proven in a more general context. In particular, a significant part of the material is dedicated to the normed space of continuous functions on a metric space. On the other hand, we provide the necessary background on differential geometry and complex analysis, which further determine the peculiarities in the context of spaces of analytic functions. At the end we illustrate our results on two specific examples of NSAF's, namely the Bergman and the Bloch Spaces over a general domain in Cd. We give a new proof of the reflexivity of the Bergman Space Ap(G, μ) for the case p>1 and of the Schur property of A1(G, μ). We also give new proofs for the equivalences of some of the definitions of the Bloch functions.

abstract: ABSTRACT Despite significant advancements in drug therapy, cardiovascular disease (CVD) is still the leading cause of death in the United States. Given this, research has begun to seek out alternative approaches to reduce CVD risk. One of these alternative approaches is Vitamin D supplementation. Current research has shown a link between Vitamin D status and CVD risk in both healthy and diseased populations. Among the possible mechanisms is a positive effect of Vitamin D on vascular endothelial function, which can be measured with noninvasive techniques such as flow-mediated dilation (FMD) of conduit vessels using high-resolution ultrasound. This dissertation is comprised of two studies. The first examines whether Vitamin D supplementation can improve FMD in older adults within a time period (two weeks) associated with peak increases in plasma Vitamin D concentrations after a single-dose supplementation. The second examines the effect of Vitamin D supplementation in people with Rheumatoid Arthritis (RA). The reason for looking at an RA population is that CVD is the leading cause of early mortality in people with RA. In the first study 29 Post-Menopausal Women received either 100,000 IU of Vitamin D3 or a Placebo. Their FMD was measured at baseline and 2 weeks after supplementation. After 2 weeks there was a significant increase in FMD in the Vitamin D group (6.19 + 4.87 % to 10.69 + 5.18 %) as compared to the Placebo group (p=.03). In the second study, 11 older adults with RA were given 100,000 IU of Vitamin D or a Placebo. At baseline and one month later their FMD was examined as well as plasma concentrations of Vitamin D and tumor necrosis factor-alpha; (TNF-alpha;). They also filled out a Quality of Life Questionnaire and underwent a submaximal exercise test on the treadmill for estimation of maximum oxygen uptake (VO2max). There was no significant change in FMD in Vitamin D group as compared to the Placebo group (p=.721). Additionally, there was no significant improvement in either plasma Vitamin D or TNF-alpha; in the Vitamin D group. There was however a significant improvement in predicted VO2max from the submaximal exercise test in the group receiving Vitamin D (p=.003). The results of these studies suggest that a single 100,000 IU dose of Vitamin D can enhance FMD within two week in older adults, but that a similar dose may not be sufficient to increase FMD or plasma Vitamin D levels in older adults with RA. A more aggressive supplementation regimen may be required in this patient population. / Dissertation/Thesis / Ph.D. Exercise and Wellness 2012

Semigroups of completely positive maps arise naturally both in noncommutative stochastic processes and in the dynamics of open quantum systems. Since its inception in the 1970's, the study of completely positive semigroups has included among its central topics the dilation of a completely positive semigroup to an endomorphism semigroup. In quantum dynamics, this amounts to embedding a given open system inside some closed system, while in noncommutative probability, it corresponds to the construction of a Markov process from its transition probabilities. In addition to the existence of dilations, one is interested in what properties of the original semigroup (unitality, various kinds of continuity) are preserved. Several authors have proved the existence of dilations, but in general, the dilation achieved has been non-unital; that is, the unit of the original algebra is embedded as a proper projection in the dilation algebra. A unique approach due to Jean-Luc Sauvageot overcomes this problem, but leaves unclear the continuity of the dilation semigroup. The major purpose of this thesis, therefore, is to further develop Sauvageot's theory in order to prove the existence of continuous unital dilations. This existence is proved in Theorem 6.4.9, the central result of the thesis. The dilation depends on a modification of free probability theory, and in particular on a combinatorial property akin to free independence. This property is implicit in some Sauvageot's original calculations, but a secondary goal of this thesis is to present it as its own object of study, which we do in chapter 3.

No description available.

Novel sounds in the auditory oddball paradigm elicit a biphasic dilation of the pupil (PDR) and P3a as well as novelty P3 event-related potentials (ERPs). The biphasic PDR has been hypothesized to reflect the relaxation of the iris sphincter muscle due to parasympathetic inhibition and the constriction of the iris dilator muscle due to sympathetic activation. We measured the PDR and the P3 to neutral and to emotionally arousing negative novels in dark and moderate lighting conditions. By means of principal component analysis (PCA) of the PDR data we extracted two components: the early one was absent in darkness and, thus, presumably reflects parasympathetic inhibition, whereas the late component occurred in darkness and light and presumably reflects sympathetic activation. Importantly, only this sympathetic late component was enhanced for emotionally arousing (as compared to neutral) sounds supporting the hypothesis that emotional arousal specifically activates the sympathetic nervous system. In the ERPs we observed P3a and novelty P3 in response to novel sounds. Both components were enhanced for emotionally arousing (as compared to neutral) novels. Our results demonstrate that sympathetic and parasympathetic contributions to the PDR can be separated and link emotional arousal to sympathetic nervous system activation.

No description available.

No description available.