Cho and Pak reply to Lamm et al. comment on "A Convergent Series for the QED Effective Action"

Cho and Pak reply to Lamm et al. [hep-th/0007108] comment on "A Convergent Series for the Effective Action of QED" [hep-th/0006057].Comment: 1 pag

Magnetic resonance spectroscopy of the frontal region in patients with metabolic syndrome : correlation with anthropometric measurement

Purpose: to demonstrate 1H-MR spectroscopy of the frontal region in patients with metabolic syndrome and to correlate the metabolic ratios with anthropometric measurement. Material and methods: A prospective study was conducted upon 20 patients with metabolic syndrome (10 male, 10 female; mean age 52 years) and 20 age- and sex-matched volunteers. Patients were mild-moderate (n = 14) and marked and morbid obesity (n = 6). Patients and volunteers underwent 1H-MR spectroscopy of the frontal region. The Ch/Cr and NAA/Cr ratio were calculated and correlated with anthropometric measurement. Results: The Cho/Cr and NAA/Cr of patients with Mets (1.03 ± 0.08 and 1.62 ± 0.08) were significantly different (p = 0.001) to those of volunteers (0.78 ± 0 and 1.71 ± 0.61, respectively). The Cho/Cr and NAA/Cr cutoffs used to differentiate patients from volunteers were 0.89 and 1.77 with areas under the curve of 0.992 and 0.867 and accuracy of 97% and 93%, respectively. There was a significant difference in Cho/Cr and NAA/Cr between patients with marked-morbid obesity and moderate-mild obesity (p = 0.001 respectively). Conclusions: We concluded that NAA/Cr and Cho/Cr ratios of the frontal region can differentiate patients with metabolic syndrome from volunteers and are well correlated with the anthropometric measurement

Carbohydrate Mouth Rinse Improves 1.5 h Run Performance: Is There a Dose-Effect?

There is a substantial body of recent evidence showing ergogenic effects of carbohydrate (CHO) mouth rinsing on endurance performance. However, there is a lack of research on the dose-effect and the aim of this study was to investigate the effect of two different concentrations (6% and 12% weight/volume, w/v) on 90 minute treadmill running performance. Seven active males took part in one familiarization trial and three experimental trials (90-minute self-paced performance trials). Solutions (placebo, 6% or 12% CHO-electrolyte solution, CHO-E) were rinsed in the mouth at the beginning, and at 15, 30 and 45 minutes during the run. The total distance covered was greater during the CHO-E trials (6%, 14.6 ± 1.7 km; 12%, 14.9 ± 1.6 km) compared to the placebo trial (13.9 ± 1.7 km, P 0.05). There were no between trial differences (P > 0.05) in ratings of perceived exertion (RPE) and feeling or arousal ratings suggesting that the same subjective ratings were associated with higher speeds in the CHO-E trials. Enhanced performance in the CHO-E trials was due to higher speeds in the last 30 minutes even though rinses were not provided during the final 45 minutes, suggesting the effects persist for at least 20-45 minutes after rinsing. In conclusion, mouth rinsing with a CHO-E solution enhanced endurance running performance but there does not appear to be a dose-response effect with the higher concentration (12%) compared to a standard 6% solution

Sensor development programs at NASA Ames Research Center

Two sensor development programs being conducted at the Fluid Mechanics Laboratory, NASA Ames Research Center are described, one in progress and the other being initiated. The ongoing program involves digital image velocimetry for velocity field measurements of time-dependent flows. The new program involves advanced acoustic sensors for wind tunnel applications

Adaptation to an MCFA-rich diet : effect on gastric tolerance, the capacity for MCFA oxidation, and performance while ingesting exogenous carbohydrate and structured oils during endurance exercise : a thesis presented in partial fulfilment of the requirements for the degree of Master of Sport Science at Massey University

Introduction: Elevating the availability of fatty-acids to the muscle can potentially benefit endurance exercise performance by reducing intramuscular-glycogen utilisation. Digestion of triglycerides containing long-chain fatty acids (LCFAs) is slow, and fatty acids must pass through the carnitine palmityl transferase (CPT) transport system to enter the mitochondria, which potentially limits fat oxidation during prolonged-heavy exercise. Conversely, medium-chain triglycerides (MCTs) are rapidly digested and their constituent fatty acids (MCFAs) by-pass the CPT transport system. Ingestion of MCFAs may therefore supply mitochondrial acetyl-CoA, potentially reducing the requirement for glycolytic flux during exercise. However, studies comparing carbohydrate (CHO) with CHO-containing MCFA-rich exercise supplements have revealed inconsistent results, probably because of the variation in gastrointestinal (GI) distress suffered by participants associated with MCT ingestion. Purpose: To investigate whether 2-weeks of dietary adaptation to MCFA-rich supplements reduces the severity of gastrointestinal (Gl) distress, or increases the rate of MCFA oxidation during endurance exercise. A decrease in ratings of GI distress, or an increase in MCFA oxidation was anticipated to lead to performance benefits. Method: Nine well-trained male endurance cyclists participated in a double-blind, pseudo-randomised. triple-crossover protocol. Participants were 37 ± 7.26 years, 81.36 ± 7.67 kg. training at least 8-10 h per week and riding competitively. Mean VO2 max and peak power output (PPO) were 4.84 ± 0.46 L-min-1 and 357.33 ± 20.55 W respectively. The effects of a 2-week MCFA-rich diet +13 C-enriched MCFA+CHO exercise supplement (MC-MC) on GI distress, MCFA-oxidation rate and sprint performance variables were compared against a 2-week LCFA-rich diet with either: (a) a13 C-enriched MCFA+CHO exercise supplement (LC-MC), or (b) a CMO-only supplement (LC-CHO). Dietary and exercise MCFA-rich supplements were consumed in the form of randomised-structured triacylglycerols made with a 3:1 molar ratio of MC- and LCFAs randomly esterified to glycerol backbones. Participants followed a controlled training regime whilst on the diets. The performance test consisted of a 3-h ride at 50% PPO followed by 10 maximal sprints. At rest and every 20-min throughout the ride, participant ratings of GI and exertion sensations were recorded, followed by external respiratory-gas analysis, collection of a breath sample for breathl3 C-enrichment analysis, a venous blood sample and ingestion of a supplement. Similarly, after sprints 1, 4, 7 and 10 participants recorded their GI ratings followed by a blood sample. Results: Peak MCFA-oxidation rates were 0.38 g-min-1(95% Cl 0.31-0.47) and 0.43 g-min-1(0.30-0.61, p-value = 0.21) in the MC-MC and LC-MC conditions respectively, but there was no evidence for CHO sparing following MCFA adaptation. Participant ratings of GI distress decreased slightly during exercise with 2-weeks of a diet high in MCFAs relative to LCFAs. Ratings of reflux, bloatedness, nausea, and urge to vomit were, respectively, 1.34 (0.88-3.14), 1.03 (0.74-2.27), 0.81 (0.62-1.69) and 0.93 (0.64-245) scale units lower in the MC-MC condition relative to LC-MC. The attenuation in GI distress corresponded with a tendency toward increased sprint mean power, which was 3.4% (± 5.9%, 0.25) higher in the MC-MC condition relative to LC-MC. However, sprint mean power was still lower in both the MC-MC (6.8% ± 2.8%, <0.0001) and LC-MC (10.4% ± 5.5%, 0.0004) conditions relative to LC-CHO. Mechanism covariate analysis illustrated a negative effect of the GI distress marker nausea on sprint performance. For every 1 unit increase in nausea for the MC-MC and LC- MC conditions, sprint power decreased by 6 W (± 3.8,0.004) relative to LC-CHO. Conclusion: No clear metabolic adaptation was evident with high dietary MCFA relative to LCFA. In addition, MCFA-rich exercise supplements caused a decrement in performance relative to CHO ingestion in both MC-MC and LC-MC conditions, suggesting that light- moderate GI distress still causes substantial performance detriments. There was little evidence to support the ingestion of randomised structured triglycerides high in MCFA with the intention of enhancing endurance performance

Effects of Dietary Cholesterol and its Oxidation Products on Pathological Lesions and Cholesterol and Lipid Oxidation in the Rabbit Liver

The effects of dietary cholesterol (CHO) and cholesterol oxidation productions (COPs) on the induction of pathological lesions in rabbit liver tissues were determined. Rabbits were fed with a chow containing no additives or added with 1 g CHO, 2 g CHO, 0.9 g CHO + 0.1 COPs, 0.8 g CHO + 0.2 g COPs, 0.5 g CHO + 0.5 g COPs, 1.6 g CHO + 0.4 g COPs, or 1.2 g CHO + 0.8 g COPs per kg diet. Liver lesions were induced only when the levels of CHO and COPs in the diet were very high. The amount of CHO in the liver increased when dietary CHO was increased; by comparison, dietary COPs affected liver CHO amounts to a lesser extent. The TBARS (thiobarbituric acid reactive substances) value of the liver samples also increased when dietary CHO and COP levels were elevated, and the TBARS value was more strongly affected by the amount of COPs in the diet than by the amount of CHO. At 6 and 12 weeks, COP levels were highest in the group that received 1.2 g CHO + 0.8 g COPs, followed by the 0.5 g CHO + 0.5 g COPs and 1.6 g CHO + 0.4 g COPs groups; the control (0 g) group showed the lowest COP levels among all groups. This indicated that not only dietary CHO but also COPs were involved in hypercholesterolemia-induced liver lesions when the amount of CHO and COPs was high

Observation of confined propagation in Bragg waveguides

A new type of waveguiding in a slab dielectric bounded on one side by air and on the other by a periodic layered medium (grown by molecular beam epitaxy) has been demonstrated