1,005 research outputs found
Dietary Anthocyanins: A Review of the Exercise Performance Effects and Related Physiological Responses
Foods and supplements high in anthocyanins are gaining popularity within sports nutrition. Anthocyanins are pigments within berries and other colourful fruits and vegetables. They have anti-oxidative and anti-inflammatory actions that improve recovery from exercise. Furthermore, anthocyanins can also affect vasoactive properties, including decreasing mean arterial blood pressure and increasing vasodilation during exercise. In vitro observations have shown anthocyanin- and metabolite-induced activation of endothelial nitric oxide synthase and human vascular cell migration. However, effects of anthocyanins on exercise performance without a prior muscle-damaging or metabolically demanding bout of exercise is less clear. For example, exercise performance effects have been observed for blackcurrant, but are less apparent for cherry, therefore indicating that the benefits could be due to the specific source-dependent anthocyanins. The mechanisms by which anthocyanin intake can enhance exercise performance may include effects on blood flow, metabolic pathways, and peripheral muscle fatigue, or a combination of all. This narrative review focuses on the experimental evidence for anthocyanins to improve exercise performance in humans
Effect of New Zealand Blackcurrant Extract on Performance During the Running Based Anaerobic Sprint Test in Trained Youth and Recreationally Active Male Football Players
It was observed previously that New Zealand blackcurrant (NZBC) extract reduced slowing of the maximal 15 m sprint speed during the Loughborough Intermittent Shuttle Test. We examined the effect of NZBC extract on the performance of the Running Based Anaerobic Sprint Test (RAST, 6 × 35-m sprints with 10 seconds passive recovery) in trained youth and recreationally active football players. Fifteen recreationally active (University team) (age: 20 ± 1 years, height: 174 ± 19 cm, body mass: 80 ± 13 kg) and nine trained youth players (English professional club) (age: 17 ± 0 years, height: 178 ± 8 cm, body mass: 69 ± 9 kg, mean ± SD) participated in three testing sessions. Prior to the RASTs, participants consumed two capsules of NZBC extract (600 mg?day?1 CurraNZ®) or placebo (P) for 7 days (double blind, randomised, cross-over design, wash-out at least 14 days). Ability difference between groups was shown by sprint 1 time. In the placebo condition, trained youth players had faster times for sprint 1 (5.00 ± 0.05 s) than recreationally active players (5.42 ± 0.08 s) (p < 0.01). In trained youth players, there was a trend for an effect of NZBC extract (p = 0.10) on the slowing of the sprint 1 time. NZBC extract reduced slowing of the sprint 5 time (P: 0.56 ± 0.22 s; NZBC: 0.35 ± 0.25, p = 0.02) and this was not observed in recreationally active players (P: 0.57 ± 0.48 s; NZBC: 0.56 ± 0.33, p = 0.90). For fatigue index, expressed as a % change in fastest sprint time, there was a strong trend to be lower in both trained youth and recreationally active players combined by NZBC extract (P: ?13 ± 7%; NZBC: ?11 ± 6%, p = 0.06) with 12 participants (five trained youth) experiencing less fatigue. New Zealand blackcurrant extract seems to benefit repeated sprint performance only in trained football players
Effect of New Zealand Blackcurrant Extract on Repeated Cycling Time Trial Performance
Abstract: New Zealand blackcurrant (NZBC) extract increased 16.1 km cycling time trial performance.
The aim of the present study was to examine the effect of NZBC extract on 2 × 4 km time trial
performance. Ten male cyclists (age: 30 ± 12 years, body mass: 74 ± 9 kg, height: 179 ± 7 cm, body
fat: 11 ± 3%, V˙ O2max: 55 ± 7 mL·kg−1·min−1, mean ± SD) volunteered. Participants were
familiarized with the time trials. Participants consumed capsulated NZBC extract (300 mg·day−1
CurraNZâ„¢; containing 105 mg anthocyanin) or placebo for seven days (double blind, randomised,
cross-over design, wash-out at least seven days) before 2 × 4 km time trials (10 min active
self-paced recovery between trials) (SRM ergometer, SRM International, Germany). Heart rate was
recorded and blood lactate sampled immediately after each trial and 8 min into recovery between the
trials. Times over comparable one km distances in each 4 km time trial were similar. No effect was
observed for the time to complete the first (placebo: 380 ± 28 s, NZBC: 377 ± 27 s) and second 4 km
of cycling (placebo: 391 ± 32 s, NZBC: 387 ± 30 s), within both groups the second 4 km times slower
by 11 ± 8 s and 11 ± 9 s for placebo and NZBC, respectively. However, the total time of the two 4
km cycling trials was 0.82% faster with NZBC extract (placebo: 771 ± 60 s, NZBC 764 ± 56 s, p =
0.034) with seven participants having faster total times. There was no effect of NZBC on heart rate
and lactate values at identical time points. New Zealand blackcurrant extract seems to be
beneficial in repeated
short-distance cycling time trials for overall performance
Beneficial Effects on Fasting Insulin and Postprandial Responses Through 7-day Intake of New Zealand Blackcurrant Powder
Background: Blood glucose and insulin are elevated after intake of carbohydrate, with levels returning to normal in about 2-3 hours after ingestion. We examined the effects of daily New Zealand blackcurrant intake over 7 days on fasting glucose and insulin levels and the responses of glucose and insulin during an oral glucose tolerance test (i.e. OGTT). Methods: Seventeen healthy participants (9 males, 8 females, age: 24±8 years, body mass: 75.4±16.4 kg, height 172±11 cm, body mass index: 25.3±3.3) consumed 6 g·day-1 New Zealand blackcurrant (NZBC) powder for 7 days. Every 6 g of the serving contained 138.6 mg anthocyanins, 49 mg vitamin C, and 5.2 g of carbohydrates with total phenolic content 271.6 mg. A cross-over design was used. Participants completed one OGTT before starting the supplementation (day 0) and another OGTT after 7 days of the supplementation (day 7). For the OGTT, participants were seated and consumed 75 g of glucose dissolved in 250 mL water. Finger prick capillary samples were taken before and every 30 minutes for a total of 120 minutes after consuming the glucose drink. Following duplicate glucose analysis, blood samples were centrifuged and then plasma was separated and frozen (-20°C) for triplicate insulin analysis using a human 96-well insulin enzyme-linked immunosorbent assay (IBL international, Hamburg, Germany). Results: NZBC had no effect on fasting glucose (control: 4.46±0.45; NZBC: 4.41±0.44 mmol·L1, P=0.657), although there was a trend for fasting insulin to be 14.3% lower (control: 66.5±28.2; NZBC: 57.0±29.5 pmol·L-1) (P=0.091). HOMA-IR was not different between the control and NZBC (1.81±0.73 vs 1.58±0.83) (P=0.126). With NZBC during the OGTT, plasma glucose at 60 min was 8.1% lower (control: 6.68±1.13; NZBC: 6.14±1.41 mmol·L-1; P=0.016), insulin at 30 min was 18.4% lower (control: 337.1±228.3; NZBC: 275.0±136.4 pmol·L-1; P= 0.021), and insulin at 60 min was 39.2% lower (control: 297.8±154.3; NZBC: 181.2±97.4 pmol·L-1; P= 0.002). With NZBC during the OGTTs, areas-under-the-curve for plasma glucose (control: 752.6±79.4, NZBC: 709.8±93.3 mmol·L-1·120 min) and insulin (control: 28443±12816, NZBC: 20406±7985, pmol·L-1·120 min) were 5.7% (P=0.051) and 31.1% lower (P<0.001) respectively. Conclusion: A trend for lower fasting insulin with normal glucose and lower areas under the curve for glucose and insulin suggests that repeated intake of New Zealand blackcurrant powder increases insulin sensitivity. This is the first observation of a high-anthocyanin containing berry powder to increase insulin sensitivity. Regular intake of New Zealand blackcurrant powder may be beneficial for the postprandial responses in people with type 2 diabetes or metabolic syndrome
Long-term perturbations due to a disturbing body in elliptic inclined orbit
In the current study, a double-averaged analytical model including the action
of the perturbing body's inclination is developed to study third-body
perturbations. The disturbing function is expanded in the form of Legendre
polynomials truncated up to the second-order term, and then is averaged over
the periods of the spacecraft and the perturbing body. The efficiency of the
double-averaged algorithm is verified with the full elliptic restricted
three-body model. Comparisons with the previous study for a lunar satellite
perturbed by Earth are presented to measure the effect of the perturbing body's
inclination, and illustrate that the lunar obliquity with the value 6.68\degree
is important for the mean motion of a lunar satellite. The application to the
Mars-Sun system is shown to prove the validity of the double-averaged model. It
can be seen that the algorithm is effective to predict the long-term behavior
of a high-altitude Martian spacecraft perturbed by Sun. The double-averaged
model presented in this paper is also applicable to other celestial systems.Comment: 28 pages, 6 figure
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85,000-GPM, single-stage, single-suction LMFBR intermediate centrifugal pump
The mechanical and hydraulic design features of the 85,000-gpm, single-stage, single-suction pump test article, which is designed to circulate liquid-sodium coolant in the intermediate heat-transport system of a Large-Scale Liquid Metal Fast Breeder Reactor (LS-LMFBR), are described. The design and analytical considerations used to satisfy the pump performance and operability requirements are presented. The validation of pump hydraulic performance using a hydraulic scale-model pump is discussed, as is the featute test for the mechanical-shaft seal system
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Internal fluid flow management analysis for Clinch River Breeder Reactor Plant sodium pumps
The Clinch River Breeder Reactor Plant (CRBRP) sodium pumps are currently being designed and the prototype unit is being fabricated. In the design of these large-scale pumps for elevated temperature Liquid Metal Fast Breeder Reactor (LMFBR) service, one major design consideration is the response of the critical parts to severe thermal transients. A detailed internal fluid flow distribution analysis has been performed using a computer code HAFMAT, which solves a network of fluid flow paths. The results of the analytical approach are then compared to the test data obtained on a half-scale pump model which was tested in water. The details are presented of pump internal hydraulic analysis, and test and evaluation of the half-scale model test results
Effect of New Zealand Blackcurrant Extract on Cycling Performance and Substrate Oxidation in Normobaric Hypoxia in Trained Cyclists
This study explored New Zealand blackcurrant (NZBC) extract for enhanced exercise-induced fat oxidation and 16.1 km cycling time trial (TT) performance in normobaric normoxia. The effect of NZBC extract on physiological and metabolic responses was examined during steady state cycling and a 16.1 km TT in normobaric hypoxia. This study used a randomized, double-blind, crossover design. Eleven healthy male cyclists (age: 38 ± 11 y, height: 179 ± 4 cm, body mass: 76 ± 8 kg, V ˙ O2max: 47 ± 5 mL·kg−1·min−1, mean ± SD) ingested NZBC extract (600 mg·day−1 CurraNZ® containing 210 mg anthocyanins) or a placebo (600 mg microcrystalline cellulose M102) for seven days (washout 14 days) and performed a steady state cycling test (3 × 10 min at 45%, 55% and 65% V ˙ O2max) followed by a 16.1 km TT at a simulated altitude of ~2500 meters (~15% of O2). Indirect calorimetry was used to measure substrate oxidation during steady state cycling. Intake of NZBC extract had no effect on blood glucose and lactate, heart rate, substrate oxidation, and respiratory exchange ratio during steady state cycling at 45%, 55% and 65% V ˙ O2max, and on 16.1 km TT performance (placebo: 1685 ± 92 s, NZBC extract: 1685 ± 99 s, P = 0.97). Seven days intake of New Zealand blackcurrant extract does not change exercise-induced metabolic responses and 16.1 km cycling time trial performance for moderately endurance-trained men in normobaric hypoxia
Microbial genomics amidst the Arctic crisis
The Arctic is warming – fast. Microbes in the Arctic play pivotal roles in feedbacks that magnify the impacts of Arctic change. Understanding the genome evolution, diversity and dynamics of Arctic microbes can provide insights relevant for both fundamental microbiology and interdisciplinary Arctic science. Within this synthesis, we highlight four key areas where genomic insights to the microbial dimensions of Arctic change are urgently required: the changing Arctic Ocean, greenhouse gas release from the thawing permafrost, 'biological darkening' of glacial surfaces, and human activities within the Arctic. Furthermore, we identify four principal challenges that provide opportunities for timely innovation in Arctic microbial genomics. These range from insufficient genomic data to develop unifying concepts or model organisms for Arctic microbiology to challenges in gaining authentic insights to the structure and function of low-biomass microbiota and integration of data on the causes and consequences of microbial feedbacks across scales. We contend that our insights to date on the genomics of Arctic microbes are limited in these key areas, and we identify priorities and new ways of working to help ensure microbial genomics is in the vanguard of the scientific response to the Arctic crisis
Numerically generated quasi-equilibrium orbits of black holes: Circular or eccentric?
We make a comparison between results from numerically generated,
quasi-equilibrium configurations of compact binary systems of black holes in
close orbits, and results from the post-Newtonian approximation. The
post-Newtonian results are accurate through third PN order (O(v/c)^6 beyond
Newtonian gravity), and include rotational and spin-orbit effects, but are
generalized to permit orbits of non-zero eccentricity. Both treatments ignore
gravitational radiation reaction. The energy E and angular momentum J of a
given configuration are compared between the two methods as a function of the
orbital angular frequency \Omega. For small \Omega, corresponding to orbital
separations a factor of two larger than that of the innermost stable orbit, we
find that, if the orbit is permitted to be slightly eccentric, with e ranging
from \approx 0.03 to \approx 0.05, and with the two objects initially located
at the orbital apocenter (maximum separation), our PN formulae give much better
fits to the numerically generated data than do any circular-orbit PN methods,
including various ``effective one-body'' resummation techniques. We speculate
that the approximations made in solving the initial value equations of general
relativity numerically may introduce a spurious eccentricity into the orbits.Comment: 6 pages, 4 figures, to be submitted to Phys. Rev.
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