Effect of betaine supplementation on power performance and fatigue

Background  

The purpose of this study was to examine the efficacy of 15 days of betaine supplementation on muscle endurance, power performance and rate of fatigue in active college-aged men.     

Effect of betaine supplementation on plasma nitrate/nitrite in exercise-trained men

Background  

Betaine, beetroot juice, and supplemental nitrate have recently been reported to improve certain aspects of exercise performance, which may be mechanistically linked to increased nitric oxide. The purpose of the present study was to investigate the effect of betaine supplementation on plasma nitrate/nitrite, a surrogate marker or nitric oxide, in exercise-trained men.     

Effect of SiC whiskers on thermal cycling performance of YSZ-Based sealing coating

Two types of Y₂O₃ partially stabilized ZrO₂(YSZ)-based agglomerated powders with and without SiC whiskers were prepared by spray granulation, and the flow ability, apparent density and particle size distribution of them were investigated. The thermal cycling performance and failure mechanism of conventional high temperature sealing coating and modified one with additional layer with whiskers, which were sprayed by air plasma spraying (APS), were comparatively analyzed. The results showed that, compared to the powder without whiskers, the flow ability of that with whiskers reduced by 2.32%, and the apparent density and the proportion of 45–150 μm agglomerated powder increased by 1.53% and 2.29%, respectively. The thermal cycling failure mode of conventional high temperature sealing coating was the overall spalling of ceramic coating, and the spalling position originated from the interface of thermally grown oxide (TGO)/ceramic coating. Microstructure observation indicated that the structure integrity of SiC whiskers in the additional layer sprayed by APS was still retained. The whiskers were uniformly distributed and theinterface between bonding coating and ceramic coating exhibited excellent bonding. With the additional layer containing whiskers, the thermal cycling life of the coating was increased by 102.53%. In the thermal cycling process, the “bridging” and “pulling-out” effects of whiskers located at the additional layer consumed considerable energy, which could reduce the driving force of crack growth. Besides, a porous structure of the additional layer after thermal cycling was formed due to “bridging” and “pulling-out” of whiskers, further improving the thermal cycling life of coating with the additional layer.     

椰油酰胺丙基甜菜碱的结构及其性能分析

选用洗发露中的配料椰油酰胺丙基甜菜碱作为描述对象,从椰油酰胺丙基甜菜碱的分子结构出发,分析其性能特点,采用结构特征参数辛醇-水分配系数作为理化参数,通过数学模型计算,从生物积累和生物降解两方面来预测其环境行为,并采用QASR法判断了其安全性。     

The effect of chronic soluble keratin supplementation in physically active individuals on body composition,blood parameters and cycling performance

Background

Keratins are structural, thiol-rich proteins, which comprise 90% of total poultry feather weight. Their favourable amino acid profile suggests the potential for use as a protein source and ergogenic aid for endurance athletes, following treatment to increase digestibility. This study investigated whether 4 weeks of soluble keratin (KER) consumption (0.8 g/kg bodyweight/day) by 15 endurance-trained males would have favourable effects on body composition, blood and cardiorespiratory variables, and cycling performance, compared to casein protein (CAS).

Methods

Supplementation was randomized, blinded and balanced, with a minimum eight-week washout period between trials. An exercise test to measure oxygen consumption during submaximal and maximal cycling exercise was completed at the start at and end of each intervention. Anthropometric (DEXA) and blood measures were made prior to and following each intervention period.

Results

Total body mass and percentage body fat did not change significantly (p?>?0.05). However, a significantly greater increase in bone-free lean mass (LM) occurred with KER compared to CAS (0.88 kg vs 0.07 kg; p?<?0.05). While no change in LM was evident for the trunk and arms, leg LM increased (0.45?±?0.54 kg; p?=?0.006) from baseline with KER. KER was not associated with changes in blood parameters, oxygen consumption, or exercise performance (p?>?0.05).

Conclusions

These data suggest that KER is not useful as an ergogenic aid for endurance athletes but may be a suitable protein supplement for maximizing increases in lean body mass.

     

烷基碳链对N-烷基二甲基甜菜碱性能的影响

甜菜碱表面活性剂的烷基碳链的长度对其表面活性及其它性质有不同程度的影响。通过实验测定碳链长度对泡沫力、洗涤力等的影响情况,为不同使用目的选择合适长度碳链的烷基甜菜碱提供依据。结果表明:十四烷基甜菜碱的起泡力较强,十二烷基的次之;十四、十六烷基甜菜碱的洗涤力较强,十四烷基的洗涤力更强;相对碳链长的甜菜碱活性剂具有较好的加溶作用和钙皂分散力。     

Improved cycling performance with ingestion of hydrolyzed marine protein depends on performance level

Background

The effect on performance of protein ingestion during or after exercise is not clear. This has largely been attributed to the utilization of different scientific protocols and the neglection of accounting for factors such as differences in physical and chemical properties of protein supplements and differences in athletic performance level.

Methods

We hypothesized that ingestion of unprocessed whey protein (15.3 g·h^-1) together with carbohydrate (60 g·h^-1), would provide no ergogenic effect on 5-min mean-power performance following 120 min cycling at 50% of maximal aerobic power (2.8 ± 0.2 W·kg^-1, corresponding to 60 ± 4% of VO_2max), compared to CHO alone (60 g·h^-1). Conversely, we hypothesized that ingestion of the hydrolyzed marine protein supplement NutriPeptin? (Np, 2.7 g·h^-1), a processed protein supplement with potentially beneficial amino acid composition, together with a PROCHO beverage (12.4 g·h^-1 and 60 g·h^-1, respectively) would provide an ergogenic effect on mean-power performance. We also hypothesized that the magnitude of the ergogenic effect of NpPROCHO would be dependent on athletic performance. As for the latter analysis, performance level was defined according to a performance factor, calculated from individual pre values of W_max, VO_2max and 5-min mean-power performance, wherein the performance of each subject was ranked relative to the superior cyclist whos performance was set to one. Twelve trained male cyclists (VO_2max = 65 ± 4 ml·kg^-1·min^-1) participated in a randomized double-blinded cross-over study.

Results and conclusions

Overall, no differences were found in 5-min mean-power performance between either of the beverages (CHO 5.4 ± 0.5 W·kg^-1; PROCHO 5.3 ± 0.5 W·kg^-1; NpPROCHO 5.4 ± 0.3 W·kg^-1) (P = 0.29). A negative correlation was found between NpPROCHO mean-power performance and athletic performance level (using CHO-performance as reference; Pearson R = -0.74, P = 0.006). Moreover, ingestion of NpPROCHO resulted in improved 5-min mean-power performance relative to ingestion of CHO in the six lesser performing subjects compared to the six superior performing subjects (P < 0.05). This suggests that with the current protocol, NpPROCHO provided an ergogenic effect on 5-min mean-power performance in athletes with a lower performance level.     

Recovery from a cycling time trial is enhanced with carbohydrate-protein supplementation vs. isoenergetic carbohydrate supplementation

Background

In this study we assessed whether a liquid carbohydrate-protein (C+P) supplement (0.8 g/kg C; 0.4 g/kg P) ingested early during recovery from a cycling time trial could enhance a subsequent 60 min effort on the same day vs. an isoenergetic liquid carbohydrate (CHO) supplement (1.2 g/kg).

Methods

Two hours after a standardized breakfast, 15 trained male cyclists completed a time trial in which they cycled as far as they could in 60 min (AM_ex) using a Computrainer indoor trainer. Following AM_ex, subjects ingested either C+P, or CHO at 10, 60 and 120 min, followed by a standardized meal at 4 h post exercise. At 6 h post AM_ex subjects repeated the time trial (PM_ex).

Results

There was a significant reduction in performance for both groups in PM_ex versus AM_ex. However, performance and power decreases between PM_ex and AM_ex were significantly greater (p ≤ 0.05) with CHO (-1.05 ± 0.44 km and -16.50 ± 6.74 W) vs C+P (-0.30 ± 0.50 km and -3.86 ± 6.47 W). Fat oxidation estimated from RER values was significantly greater (p ≤ 0.05) in the C+P vs CHO during the PM_ex, despite a higher average workload in the C+P group.

Conclusion

Under these experimental conditions, liquid C+P ingestion immediately after exercise increases fat oxidation, increases recovery, and improves subsequent same day, 60 min efforts relative to isoenergetic CHO ingestion.     

Effect of artificial weathering and temperature cycling on the performance of coating systems used for wooden windows

The effects of ultraviolet light irradiation and water spray and temperature cycling on the color stability of waterborne coating systems on spruce were investigated. The test samples were treated with three coating systems (white and brown pigmented acrylate waterborne coatings systems with different layering) from six producers. The artificial weathering was carried out based on standardized (504 h) and increased weathering parameters (504 h). Thirty cycles of temperature changes were performed. Discoloration suggesting the rate of degradation process and color stability was measured by a spectrophotometer in L*a*b* color space. The results showed greater color stability of white coating systems during both experiments. The producer of acrylate coatings with iodopropynyl butyl carbamate and permethrin as biocides and benzotriazole, silicon dioxide and methylsiloxane as additives was characterized by the best coatings performance. The most sensitive color parameter to describe the surface quality as a result of irradiation and water spray has proven to be a change of lightness. A tendency towards degradation with increasing lightness was observed during weathering. The effect of temperature itself on color change was minimal. Scanning electron microscopy and energy dispersive spectroscopy revealed microscopic changes of coatings caused by artificial weathering.     

甜菜碱对溶菌酶去折叠热力学和复性动力学的影响

应用荧光分析技术考察了甜菜碱对溶菌酶在盐酸胍溶液中稳定性的影响;并提出将甜菜碱作为添加剂应用于彻底变性还原溶菌酶的复性;同时应用表观竞争反应动力学模型分析了不同浓度甜菜碱对溶菌酶复性动力学的影响特性。结果表明,甜菜碱对溶菌酶具有稳定作用,可以作为添加剂促进变性还原溶菌酶的复性。甜菜碱可以抑制复性过程溶菌酶分子间的聚集,同时提高溶菌酶的复性速率,从而提高溶菌酶的复性收率。     

Effect of 28 days of creatine ingestion on muscle metabolism and performance of a simulated cycling road race

Purpose

The effects of creatine supplementation on muscle metabolism and exercise performance during a simulated endurance road race was investigated.

Methods

Twelve adult male (27.3 ± 1.0 yr, 178.6 ± 1.4 cm, 78.0 ± 2.5 kg, 8.9 ± 1.1 %fat) endurance-trained (53.3 ± 2.0 ml* kg^-1* min^-1, cycling ~160 km/wk) cyclists completed a simulated road race on a cycle ergometer (Lode), consisting of a two-hour cycling bout at 60% of peak aerobic capacity (VO_2peak) with three 10-second sprints performed at 110% VO_{2 peak} every 15 minutes. Cyclists completed the 2-hr cycling bout before and after dietary creatine monohydrate or placebo supplementation (3 g/day for 28 days). Muscle biopsies were taken at rest and five minutes before the end of the two-hour ride.

Results

There was a 24.5 ± 10.0% increase in resting muscle total creatine and 38.4 ± 23.9% increase in muscle creatine phosphate in the creatine group (P < 0.05). Plasma glucose, blood lactate, and respiratory exchange ratio during the 2-hour ride, as well as VO_{2 peak}, were not affected by creatine supplementation. Submaximal oxygen consumption near the end of the two-hour ride was decreased by approximately 10% by creatine supplementation (P < 0.05). Changes in plasma volume from pre- to post-supplementation were significantly greater in the creatine group (⁺14.0 ± 6.3%) than the placebo group (^-10.4 ± 4.4%; P < 0.05) at 90 minutes of exercise. The time of the final sprint to exhaustion at the end of the 2-hour cycling bout was not affected by creatine supplementation (creatine pre, 64.4 ± 13.5s; creatine post, 88.8 ± 24.6s; placebo pre, 69.0 ± 24.8s; placebo post 92.8 ± 31.2s: creatine vs. placebo not significant). Power output for the final sprint was increased by ~33% in both groups (creatine vs. placebo not significant).

Conclusions

It can be concluded that although creatine supplementation may increase resting muscle total creatine, muscle creatine phosphate, and plasma volume, and may lead to a reduction in oxygen consumption during submaximal exercise, creatine supplementation does not improve sprint performance at the end of endurance cycling exercise.     

Effect of hydrogen bonding and moisture cycling on the compressive performance of poly-pyridobisimidazole (M5) fiber

A clear correlation between the degree of intermolecular hydrogen bonding (H-bonding) and axial compressive strength of pyridobisimidazole (M5) as-spun fiber specimens subjected to varying annealing conditions has been established by means of Fourier transform infrared microspectroscopy and single fiber elastica loop testing. As the water initially contained in the as-spun fiber is removed by heat treatment, improvements in polymer chain orientation promote the formation of intermolecular H-bonds, leading to enhanced fiber compressive strength values. M5 fiber specimens with the highest degree of intermolecular H-bonding of 96 ± 1% are found to have a compressive strength of 1.72 ± 0.09 GPa. Moisture cycling experiments of M5 annealed specimens have provided direct evidence of partial H-bond reversibility in this material, as saturation of M5 annealed fiber resulted in the reduction of the degree of intermolecular H-bonding from 93 to 64%. Upon drying the fiber at 120 °C in an inert atmosphere, the degree of H-bonding returned to the original value of 93%. However, repeated fiber moisture cycling resulted in a monotonic reduction in the degree of H-bonding in both the saturated condition (53%) and dry state (62%). The compressive strength of saturated and dried specimens after moisture cycling was found to be statistically equivalent at a reduced level of 1.29 GPa. The original degree of H-bonding and compressive strength could be recovered by re-annealing the fiber under tension.     

磷酸铁锂高温循环性能的改善

磷酸铁锂结构稳定、循环性能优异,但是随着主机厂家对质保要求的不断提升,磷酸铁锂仍面临着高温循环性能不能满足客户要求的情况。以磷酸铁锂正极锂离子电池为研究对象,分别对比了基础电解液体系和改善电解液体系[在基础电解液中添加二氟二草酸硼酸锂（LiODFB）]对电池高温循环性能的影响。对循环后的电池采用直流内阻（DCIR）、电化学交流阻抗谱（EIS）、d Q/d U（恒定的电压间隔内电池容量的变化）曲线等无损分析方式进行数据对比,结果表明改善电解液体系电池的电荷转移阻抗进一步降低。通过对电池进行解剖,对两种电解液体系的电池极片进行了厚度分析、X射线衍射（XRD）分析、扫描电镜（SEM）分析、电感耦合等离子体发射光谱（ICP）元素分析等,结果表明改善电解液体系的电池在抑制负极表面副反应、减少正极铁溶出方面具有明显的效果,因此电池的高温循环性能更好。     

Effect of chloride salt, freeze–thaw cycling and externally applied load on the performance of the concrete

The effect of sodium chloride solution, freeze–thaw cycling and externally applied load on the performance of concrete was experimentally investigated. The results show that the concrete specimens subjected to freeze–thaw cycling scaled more severely in chloride salt solution than those in water, and weight losses of the specimens tested in chloride salt solution were twice as much as those tested in water. However, dynamic modulus of elasticity of the concrete specimens decreased more slowly in chloride salt solution than in water due to the decline in the freezing point of the chloride salt solution compared with water. It is also shown that the performance deterioration in the concrete subjected to multidamaging processes was significantly accelerated. The larger the stress ratios, the fewer freeze–thaw cycles the concrete could bear. When steel fiber is incorporated, performance degradation in the steel fiber-reinforced concrete exposed to the multidamaging processes could be considerably retarded.     

Effect of 1-butyl-1-methylpyrrolidinium hexafluorophosphate as a flame-retarding additive on the cycling performance and thermal properties of lithium-ion batteries

1-Butyl-1-methylpyrrolidinium hexafluorophosphate (BMP-PF₆) was used as a flame-retarding additive in the liquid electrolyte, and the influence of BMP-PF₆ content on cycling performance and thermal properties of lithium-ion batteries was investigated. Self-extinguishing time and DSC studies demonstrated that the addition of BMP-PF₆ to the electrolyte provided a significant suppression in the flammability of the electrolyte and an improvement in the thermal stability of the cell. The optimum BMP-PF₆ content in the electrolyte was found to be 10 wt.% for improving safety without degrading cycling performance of the cell.