39 research outputs found

    Serum IL-6 Is Increased During Performance Cycling After Energy Drink Consumption

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    Energy Drinks (ED) have become popular preexercise supplements due to the stimulant effects of their ingredients such as caffeine. Other ingredients including carbohydrate (CHO), glucuronolactone and taurine may also contribute to performance enhancement. Purpose: The purpose of this study was to investigate the influence of energy drink consumption on cycling performance, substrate oxidation and immune-related variables. Methods: This study was a blinded, randomized, cross-over design with 3 experimental conditions. Eleven trained male cyclists (mean age 33.4±8.9 yr, body mass 81±7.6 kg, VO2max 51.72±3.4 ml*kg-1*min-1) consumed 3 different 500 ml beverages: 1) Energy Drink (ED1- 2.0g taurine, 1.2 g glucoronolactone, 160 mg caffeine, 54 g CHO, 40 mg niacin, 10 mg pantothenic acid, 10 mg vitamin B6, and 10 μg vitamin B12), 2) cola matched for caffeine and CHO (ED2), or 3) non-caloric sparkling water (ED3) 55 min prior to racing. Performance was measured as time to complete a 25-mile simulated road race. Blood was collected pre-drink (PrD), 30 minutes after drink (pre-exercise, PrEx), during exercise at mile 5 (M5), mile 15 (M15), and immediately (PoEx) & 30 min post-exercise (30min). Results: Performance time was not different among trials (ED1 4117±161, ED2 4132±230, ED3 4173±225 s). PrEx IL-6 was not different among ED1, 2 or 3 (0.61±0.09, 0.78±0.1, 0.56±0.07 pg*mL-1, respectively). PoEx IL-6 was greatest after ED1 while ED2 IL-6 response was greater than ED3 (10.2±1.6, 6.7±0.6, 4.8±0.7 pg*ml-1, p\u3c0.001). IL-6 declined after ED1 & ED2 by 30min, but remained significantly greater than baseline after all trials (5.3±1, 4.1±0.5, 3.6±0.7, at 30min, ED1, 2 and 3, respectively, p\u3c0.001). Cycling increased leukocyte number in all conditions with ED1 leukocyte number greater than that of ED3 at M15 (9.8±0.6, 8.5±0.3 x10^6 cells/mL, p=0.012). Mean fat oxidation was greater in ED3 compared to ED2 (0.43±0.06, 0.28±0.04 g*min-1, p=0.033) but did not differ between ED1 (0.32±0.06) and ED3. Fat oxidation was increased in all trials from M5 (0.27±0.06, 0.28±0.05, 0.40±0.07, ED1, 2, 3 respectively) to M15 (0.46±0.08, 0.42±0.06, 0.61±0.06, ED1, 2, 3 respectively, p\u3c0.001). Conclusion: Coingestion of caffeine and CHO prior to endurance cycling significantly increased the IL-6 response to exercise, and the additional ingredients of ED1 appear to have further augmented this response. ED1 also appears to have increased leukocyte number compared to ED3 and fat oxidation so that it was similar to that observed during ED3. The observed results may be consequent to SNS stimulation via caffeine or other ingredients in ED1

    Multidisciplinary Applications of Detached-Eddy Simulation to Separated Flows at High Reynolds Numbers

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    We focus on multidisciplinary applications of detached-eddy simulation (DES), principally flight mechanics and aeroelasticity. Specifically, the lateral instability (known as abrupt wing stall) of the preproduction F/A-18E is reproduced using DES, including the unsteady shock motion. The presence of low frequency pressure oscillations due to shock motion in the current simulations and the experiments motivated a full aircraft calculation, which showed low frequency high-magnitude rolling moments that could be a significant contributor to the abrupt wing stall phenomenon. DES is also applied to the F-18 high angle of attack research vehicle (HARV) at a moderate angle of attack to reproduce the vortex breakdown leading to vertical stabilizer buffet. Unsteady tail loads are compared to flight test data. This work lays the foundation for future deforming grid calculations to reproduce the aero-elastic tail buffet seen in flight test. Solution based grid adaption is used on unstructured grids in both cases to improve the resolution in the separated region. Previous DoD Challenge work has demonstrated the unique ability of the DES turbulence treatment to accurately and efficiently predict flows with massive separation at flight Reynolds numbers. DES calculations have been performed using the Cobalt code and on unstructured grids, an approach that can deal with complete configurations with very few compromises. A broad range of flows has been examined in previous Challenge work, including aircraft forebodies, airfoil sections, a missile afterbody, vortex breakdown on a delta wing, and the F-16 and F-15E at high angles-of-attack. All DES predictions exhibited a moderate to significant improvement over results obtained using traditional Reynolds-averaged models and often excellent agreement with experimental/flight-test data. DES combines the efficiency of a Reynolds-averaged turbulence model near the wall with the fidelity of Large-Eddy Simulation (LES) in separated regions. Since it uses Large-Eddy Simulation in the separated regions, it is capable of predicting the unsteady motions associated with separated flows. The development and demonstration of improved methods for the prediction of flight mechanics and aeroelasticity in this Challenge is expected to reduce the acquisition cost of future military aircraft

    Energetic signatures of single base bulges: thermodynamic consequences and biological implications

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    DNA bulges are biologically consequential defects that can arise from template-primer misalignments during replication and pose challenges to the cellular DNA repair machinery. Calorimetric and spectroscopic characterizations of defect-containing duplexes reveal systematic patterns of sequence-context dependent bulge-induced destabilizations. These distinguishing energetic signatures are manifest in three coupled characteristics, namely: the magnitude of the bulge-induced duplex destabilization (ΔΔGBulge); the thermodynamic origins of ΔΔGBulge (i.e. enthalpic versus entropic); and, the cooperativity of the duplex melting transition (i.e. two-state versus non-two state). We find moderately destabilized duplexes undergo two-state dissociation and exhibit ΔΔGBulge values consistent with localized, nearest neighbor perturbations arising from unfavorable entropic contributions. Conversely, strongly destabilized duplexes melt in a non-two-state manner and exhibit ΔΔGBulge values consistent with perturbations exceeding nearest-neighbor expectations that are enthalpic in origin. Significantly, our data reveal an intriguing correlation in which the energetic impact of a single bulge base centered in one strand portends the impact of the corresponding complementary bulge base embedded in the opposite strand. We discuss potential correlations between these bulge-specific differential energetic profiles and their overall biological implications in terms of DNA recognition, repair and replication

    Simplicity in Visual Representation: A Semiotic Approach

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    Simplicity, as an ideal in the design of visual representations, has not received systematic attention. High-level guidelines are too general, and low-level guidelines too ad hoc, too numerous, and too often incompatible, to serve in a particular design situation. This paper reviews notions of visual simplicity in the literature within the analytical framework provided by Charles Morris' communication model, specifically, his trichotomy of communication levels—the syntactic, the semantic, and the pragmatic. Simplicity is ultimate ly shown to entail the adjudication of incompatibilities both within, and between, levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68281/2/10.1177_105065198700100103.pd

    School Experiences and Cannabis Blunt Use Among African American Youth

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