Automatic Segmentation of Brachial Artery based on Fuzzy C-Means Pixel Clustering from Ultrasound Images

Automatic extraction of brachial artery and measuring associated indices such as flow-mediated dilatation and Intima-media thickness are important for early detection of cardiovascular disease and other vascular endothelial malfunctions. In this paper, we propose the basic but important component of such decision-assisting medical software development – noise tolerant fully automatic segmentation of brachial artery from ultrasound images. Pixel clustering with Fuzzy C-Means algorithm in the quantization process is the key component of that segmentation with various image processing algorithms involved. This algorithm could be an alternative choice of segmentation process that can replace speckle noise-suffering edge detection procedures in this application domain

Effects of Grape Seed Extract Supplementation on Endothelial Function and Endurance Performance in Basketball Players

While dietary polyphenols supplements can improve endothelial function and blood flow to exercise, the effects of chronic supplementation with grape seed extract (GSE) containing a high dose of polyphenols on endurance performance are not known. Accordingly, in 12 elite athletes, we compared the effects of both GSE and placebo (PL) on submaximal VO2, time to exhaustion performance, and endothelial function during progressive cycling exercise for 14 days. Endothelial function was evaluated from the brachial artery via flow-mediated dilation (FMD). Compared to PL, GSE decreased submaximal VO2 at 80% and 120% of VO2peak and increased the time to exhaustion (p < 0.05). GSE also resulted in FMD-induced increase in brachial artery diameter (14.4 ± 5.2% vs. 17.6 ± 4.5%, p = 0.035). We demonstrated that chronic supplementation with GSE improved endurance performance and these effects may partially be due to vasodilation in active skeletal muscle mediated by enhanced endothelial function. Thus, our results suggest that GSE appears to be an ergogenic nutraceutical that can improve exercise performance in elite athletes

Augmented Hemodynamic Responses in Obese Young Men during Dynamic Exercise: Role of the Muscle Metaboreflex

Studies found that cardiovascular responses to exercise are enhanced in individuals with obesity and are associated with a greater cardiac output (CO) response compared to normal weight controls. However, the mechanisms underlying these altered responses during dynamic exercise are not clear. We investigated whether the cardiovascular responses mediated by the muscle metaboreflex (MMR) activation are augmented in obese men during both static and dynamic exercise. Twenty males (10 obese (OG) and 10 non-obese (NOG)) were studied. Changes in CO, mean arterial pressure (MAP), and total vascular conductance (TVC) were compared between the two groups during dynamic handgrip exercise (DHE), post-exercise muscular ischemia (PEMI), and dynamic exercise corresponding to 40%, 60% and 80% workloads. Subjects completed 2 min of DHE at 30% of MVC, followed by 2 min of PEMI. MAP, CO, and TVC responses to DHE and dynamic exercise were significantly higher in OG, whereas there were no differences during PEMI. Increases in CO and MAP during mild to heavy dynamic exercise were seen in both groups, but the changes in these variables were greater in the OG. There were no significant differences in TVC between the two groups. Compared to NOG, the augmented blood pressure response to DHE and dynamic exercise in OG was associated with a greater increase in CO. Thus, the augmented CO and MAP responses were not associated with the activation of the MMR. Consequently, additional factors specific to obesity, such as the mechanoreflex, may have been involved

Effect of a Taekwondo Academy’s Technology-Based Self-Service on Perceived Value and Intention to Use Continuously in the Interaction between Humans and Technology

As the competition among businesses intensifies and customer needs become increasingly diverse and complex, the need for personalized service has emerged. This study examines the effect of technology-based self-service (TBSS) characteristics of a Taekwondo academy on perceived value and intention to use continuously. The study sample consisted of masters managing a Taekwondo academy who had prior experience with TBSS. A total of 188 responses were collected using an online questionnaire. The collected data were analyzed using SPSS 23.0 and AMOS 23.0. The results demonstrated the following: first, among the sub-factors of TBSS characteristics, reliability, usefulness, and enjoyment were found to affect the perceived value positively; second, among the sub-factors of TBSS characteristics, usefulness and ease of use positively affected the intention to use continuously; and finally, the perceived value was found to affect the intention to use continuously positively. This study provides practical implications for more efficient use of the TBSS provided by a Taekwondo academy by discovering the relationship between the TBSS configuration of the Taekwondo academy, perceived value, and intention to use continuously

Histamine H2 Receptor Blockade Augments Blood Pressure Responses to Acute Submaximal Exercise in Males

Histamine is a potent vasodilator that has been found to increase during exercise. We tested the hypothesis that histamine attenuates blood pressure, cardiac output (CO) and vascular resistance responses to short term, submaximal dynamic exercise during H2 receptor blockade. Fourteen healthy men (20-29 yr) were studied. Systolic (SBP), diastolic (DBP) and mean (MAP) arterial blood pressure and heart rate (HR) were assessed at rest and during the last min of 10 min of submaximal cycling exercise (60% of V02peak) in the absence and presence of histamine H2 receptor blockade (ranitidine, 300 mg). Stroke volume (SV) (impedance cardiography) and plasma norepinephrine (NE) were measured and CO, rate x pressure product (RPP) and total peripheral resistance (TPR) were calculated. Plasma levels of histamine were also measured. H2 blockade had no effects on any variables at rest. During exercise, SBP (184± 3 vs. 166±2 mmHg), MAP (121±2 vs. 112±5 mmHg), RPP (25.9±0.8 x 103 vs. 23.5±0.8.0 x 103 mmHg • beats/min) were greater during blocked conditions (PThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Effect of a Taekwondo Academy’s Technology-Based Self-Service on Perceived Value and Intention to Use Continuously in the Interaction between Humans and Technology

As the competition among businesses intensifies and customer needs become increasingly diverse and complex, the need for personalized service has emerged. This study examines the effect of technology-based self-service (TBSS) characteristics of a Taekwondo academy on perceived value and intention to use continuously. The study sample consisted of masters managing a Taekwondo academy who had prior experience with TBSS. A total of 188 responses were collected using an online questionnaire. The collected data were analyzed using SPSS 23.0 and AMOS 23.0. The results demonstrated the following: first, among the sub-factors of TBSS characteristics, reliability, usefulness, and enjoyment were found to affect the perceived value positively; second, among the sub-factors of TBSS characteristics, usefulness and ease of use positively affected the intention to use continuously; and finally, the perceived value was found to affect the intention to use continuously positively. This study provides practical implications for more efficient use of the TBSS provided by a Taekwondo academy by discovering the relationship between the TBSS configuration of the Taekwondo academy, perceived value, and intention to use continuously

Dietary Nitrate Supplementation Attenuates Blood Pressure in Young Prehypertensive Men during Exercise

Background: Acute dietary nitrate (NO3-) supplementation with beetroot juice (BRJ) can lower blood pressure (BP) at rest and during exercise in healthy individuals; however, the effects on endothelial function and BP response to dynamic exercise are not known in prehypertensive individuals. We compared the effects of 15 days BRJ supplementation on hemodynamic responses during progressive dynamic exercise. Methods: In a double-blind, randomized, crossover design, 11 healthy, prehypertensive men were supplemented with either BRJ (5.6 mmol, 70 ml BRJ) or a placebo (PL)(70 ml control drink) every day for 15 days. Participants completed two bouts of cycling exercise at each of the two workout intensities, corresponding to 30% and 60% of their predetermined VO2peak values. Flowmediated dilation (FMD) of the brachial artery and plasma concentration of NOx (NO3- and NO2-) were measured, and the mean arterial pressure (MAP), cardiac output (CO), and total vascular conductance (TVC) were assessed at rest and during exercise before and after each treatment. Results: BRJ supplementation significantly increased resting plasma NOx concentrations (123.0±11.3 vs. 181.9±19.5 μM) and the brachial artery FMD (9.8±1.0 vs. 13.5±1.4%) compared to no change after ingestion of the PL. Compared with the PL, BRJ supplementation reduced the MAP (101±1 vs. 99±1 mmHg) at rest and this reduction occurred across workloads, while the TVC was increased only during exercise (p<0.05). There was no difference in CO. Conclusions: 15 days of dietary nitrate supplementation could improve endothelial function and contribute to attenuation of an exaggerated exercise BP resulting mainly from a failure to reduce peripheral resistance during exercise