The effects of creatine and glycerol hyperhydration on running economy in well trained endurance runners

Background

No published data is currently available that describes the dietary patterns or physiological profiles of athletes participating on the Kuwaiti national fencing team and its potential impact on health and physical performance. The purpose of this investigation was to: 1) collect baseline data on nutrient intake 2) collect, analyze and report baseline for body composition, plasma lipid and lipoprotein concentrations during the competitive season, 3) compare the results with the international norms, 4) and provide necessary health and nutritional information in order to enhance the athletes' performance and skills.

Methods

Fifteen national-class fencers 21.5 ± 2.6 years of age participated in this study. Food intake was measured using a 3-day food record. Body composition was estimated using both the BOD POD and Body Mass Index (BMI). Total blood lipid profiles and maximum oxygen consumption was measured for each of the subjects during the competitive season.

Results

The results of the present study showed significant differences in dietary consumption in comparison with the recommended dietary allowances (RDA). The blood lipids profile and body composition (BMI and % body fat) were in normal range in comparison with international norms However, the average VO_{2 max} value was less than the value of the other fencers.

Conclusion

Due to the results of the research study, a dietary regimen can be designed that would better enhance athletic performance and minimize any health risks associated with nutrition. Percent body fat and BMI will also be categorized for all players. In addition, the plasma blood tests will help to determine if any of the players have an excessive level of lipids or any blood abnormalities. The outcomes of present study will have a direct impact on the players health and therefore their skills and athletic performance.     

Influence of conjugated linoleic acids on body composition and selected serum and endocrine parameters in resistance‐trained athletes

Conjugated linoleic acids (CLA) are believed to influence body composition, blood lipids and certain endocrine parameters in animals and humans. The aim of this study was to investigate the effects of a six months dietary supplementation of 7 g CLA‐oil (containing 54% CLA) daily in two groups of male and female resistance‐trained athletes who were at a different training stage. The volunteers were matched according to their previous training: 7 beginners (3♀/4♂) and 7 advanced athletes (2♀/5♂). During the intervention period they performed a standardized training routine three times per week. Blood samples were taken and body mass index, body composition (bioelectrical impedance assessment) and nutrient intake (7‐day food record) were recorded at baseline as well as during and following dietary supplementation Results: Serum lipid concentrations, serum leptin, soluble leptin receptor and IGF‐I levels or body composition were similar in the two categories of athletes after CLA supplementation. However, despite a higher energy intake, a significant reduction of body fat (P <0.05) was observed and both groups tended to increase their body cell mass (not significant). Total body water increased in the novice athletes (P <0.05). Furthermore, total cholesterol (P = 0.049) increased over baseline levels in the novice athletes. These levels remained within the physiological range. In all athletes there was a significant correlation between percentage body fat and leptin (baseline: r² = 0.46, P = 0.01, CLA: r² = 0.49, P = 0.011), as well as between fat mass and serum leptin levels (baseline: r² = 0.35, P = 0.033, CLA: r² = 0.60, P = 0.002). Conclusions: Over a period of six months no differences were observed in the effects of a commercial CLA‐triacylglyceride (54% CLA, 7g/d) on selected endocrine parameters, blood lipids, food intake and body composition between advanced and novice resistance‐trained athletes who take part in a regular training program.     

Fat intake and injury in female runners

Background  

Our purpose was to determine the relationship between energy intake, energy availability, dietary fat and lower extremity injury in adult female runners. We hypothesized that runners who develop overuse running-related injuries have lower energy intakes, lower energy availability and lower fat intake compared to non-injured runners.     

注塑流道设计的解决案例

结晶性材料注塑件的拐角处,往往存在着缩孔和错误的圆弧角度。扩大注道和流道的尺寸可有效改善部分注塑缺陷。增大浇口尺寸可以降低机筒的加热量,也就意味着既可缩短成型周期,同时又可降低成本。     

Tuning substrate roughness to improve uniform growth and photocurrent response in anodic TiO2 nanotube arrays

Here we report on the effect of Ti substrate surface roughness on the morphology of anodized TiO₂ nanotube arrays (TNAs), as well as their crystal structure and photocurrent response measured in the backside illuminated dye-sensitized solar cells (DSSCs). TNAs grown on Ti substrates with higher roughness exhibited a non-uniform morphology, which encompassed both thick and thin-walled nanotubes. Reduction of the substrate roughness by different polishing methods causes the morphology of all of nanotubes to become uniform with thin wall thickness. Moreover, the compressive strain was reduced by decreasing the roughness according to the X-ray diffraction patterns. DSSCs fabricated using TNAs grown on the smoothest substrate showed a significantly higher conversion efficiency than that of the TNAs grown on the roughest substrate by a factor of 100%. Furthermore, TNAs grown on the smoothest substrate showed higher electron lifetime and lower recombination. Therefore, it has an enhancing effect on the photocurrent response of the anodized TNAs in backside illuminated DSSCs.     

Schungite for improving the durability of the refractory lining in blast furnace runners

A technology for manufacturing refractory ramming mixtures for the runners of blast furnaces is proposed based on the use of schungite in place of the conventional coke. The resistance of the lining to attack by molten metal and slag and its service life improved significantly using silicon carbide produced from schungite. __________ Translated from Novye Ogneupory, No. 5, pp. 29–31, May, 2006.     

A model for the transient flow of thermoplastics in annular hot runners

Annular hot runner systems, in which the inner surface is heated and the outer surface cooled, are being used increasingly in the injection molding of thermoplastics. In this paper a computer model which has been developed to calculate transient pressure, temperature, and velocity fields is described. Using the properties of acrylonitrile-butadiene-styrene for illustration, some detailed temperature and velocity profiles computed with the model are presented for atypical hot runner section. The effects of a number of design and operating variables on the pressure drop are also presented.     

Role of the substrate state in electrochemical nucleation

The possibility to obtain information about the substrate state and the energetic characteristics of small clusters is discussed in the case of electrochemical nucleation on a foreign substrate. Conclusions are drawn about the character of the supercritical clusters location on the electrode surface.     

Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists

Background

It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat.

Purpose

To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala).

Methods

22 healthy endurance trained cyclists were randomly assigned to receive either 20?g/day (4?×?5?g/day) of Cr, 2?g ^.kg^-1 BM per day (4?×?0.5?g ^.kg^-1 BM per day) of Gly and 150?g/day (4?×?37.5?g/day) of Glu or 20?g/day (4?×?5?g/day) of Cr monohydrate, 2?g ^.kg^-1 BM per day (4?×?0.5?g ^.kg^-1 BM per day) of Gly (100?g/day (4?×?25?g/day) of Glu and 1000?mg/day (4?×?250?mg/day) of Ala for 7?days for 7?days. Exercise trials were conducted pre- and post-supplementation and involved 40?min of constant-load cycling exercise at 70% O₂ max by a self-paced 16.1?km time trial at 30°C and 70% relative humidity.

Results

Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P?=?0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P?=?0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3?±?2.1 beats/min and by 4.8?±?3.3 beats/min (mean ± SD) and Tcore by 0.2?±?0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups.

Conclusions

In comparison to the established hyper hydrating Cr/Gly/Glu supplement, supplement containing Cr/Gly/Ala and decreased amount of Glu provides equal improvements in thermoregulatory and cardiovascular responses during exercise in the heat.     

Role of membranes and activated carbon in the removal of endocrine disruptors and pharmaceuticals

Endocrine disrupting chemicals and pharmaceuticals represent two classes of emerging contaminants that are ubiquitously present in municipal wastewater effluents. Some of these contaminants have been shown to impact aquatic organisms at trace concentrations (i.e., ng/L). Moreover, the public has expressed human health concerns regarding the presence of emerging contaminants in water reuse projects. The primary objective of this investigation was to determine the efficacy of various membranes and activated carbons for the removal of endocrine disruptors, pharmaceuticals, and personal care products. A suite of structurally diverse target compounds was selected for evaluation based largely upon occurrence and molecular structure. Several membrane types and applications were evaluated at pilot- and/or full-scale, including: microfiltration, ultrafiltration, nanofiltration, reverse osmosis, electrodialysis reversal, membrane bioreactors, and combinations of membranes in series. Granular activated carbon was evaluated at bench-scale using rapid small scale column tests and at two full-scale utilities. Microfiltration and ultrafiltration were found to reject very few target compounds; however, some loss of steroidal type compounds was observed. Nanofiltration and reverse osmosis were capable of significant rejection of nearly all target compounds, though compounds were detectable at trace levels in permeates. Granular activated carbon was highly effective at removing all target chemicals. However, break-through curves clearly demonstrated that compounds with greater hydrophilicity breach activated carbon faster than hydrophobic compounds. In full-scale applications, the impact of regeneration was observed as activated carbon filters that received regular regeneration had minimal breakthrough of organic contaminants, while non-regenerated filters displayed no removal of target compounds. Findings confirm that membrane and carbon processes are capable of greatly reducing the concentrations of emerging contaminants; however, several compounds are detectable in membrane permeate and carbon effluent.     

Mutations of phenylalanine-193 in the putative substrate access channel alter the substrate specificity of cytochrome P450cam

The Phe-193 residue on the surface of cytochrome P450_cam is part of a cluster of residues proposed to undergo dynamic fluctuations to permit the entry of substrates into the active site pocket. The role of this residue in the activity of P450_cam has been investigated. The F193A, F193V, F193I, and F193L mutations were introduced into the Y96F mutant, which had been shown to oxidize a wider range of molecules at faster rates than the wild-type enzyme. The F193L mutation had very little effect, while the F193A and F193I mutations reduced the camphor oxidation rate and almost abolished the styrene and naphthalene oxidation activity of the Y96F mutant. In contrast, the high activity of the Y96F mutant for the oxidation of adamantane, hexane, and 3-methylpentane was largely retained, although the product distributions were significantly altered. This dramatic difference between the F193L and F193I mutations warrants further investigation. The turnover rates of the Y96F–F193I with all the substrates showed the same dependence on the Pd:P450_cam concentration ratio as for the Y96F mutant, clearly indicating that if the F193 mutations had affected substrate access, substrate entry was still fast compared to the first electron transfer, which remained the rate-limiting step for the overall reaction. We concluded that the F193A and F193I mutations shifted the substrate specificity of P450_cam by causing structural changes that were relayed from their surface position down to the vicinity of the heme. The altered substrate binding resulted in differential electron transfer kinetics between classes of compounds.     

Theory of the substrate length in polymer crystallization: Surface roughening as an inhibitor for substrate completion

A model is proposed for the physical origin of the substrate length L that appears in the customary treatment of the regime I→II growth rate transitions which occur in certain polymers during crystallization from the melt. (A previous analysis of growth rate measurements showed that L ≈ 0.77 μm at the I→II transition in polyethylene). L is treated as a ‘persistence length’ between defects that have the capacity to inhibit substrate completion. The defects are pictured as resembling the Greek letter Ω (omega) in their most extended state; in their normal state they are represented as hemispherical or disc-like amorphous patches that are pinned onto the substrate. The omega defect can form on the substrate by drawing in a portion of one of the cilia, loose loops, or interlamellar links that are characteristic of the ‘variable cluster’ representation of the molecular morphology of lamellar semicrystalline polymers. The formulation relates L to the equilibrium free energy of formation of the omega defect, which is viewed as being principally entropic. Thus we derive $\text{L∝(}\text{stem width}\text{) ×}\text{exp}\text{(?}\text{ΔS}\text{R}\text{)}$. From the known value of L for polyethylene, it is determined that the experimental entropy of formation of the defect is ΔS_expt. = ? 12.6±1.5 cal mole^?1 deg^?1. This is justified on basic grounds by first applying nucleation theory to estimate the number of chain units $\text{n}{}_{\mathrm{\Omega }}$ in the defect of critical size. Then from partition functions for once- and twice-pinned polymer chains on a surface, which gives $\text{ΔS = ?fR}\text{ln}\text{n}{}_{\mathrm{\Omega }}$ with f～ 2.0 to 2.5 depending on defect shape, one arrives at a theoretical estimate of ΔS for the omega defect in polyethylene that is in good agreement with the experimental value. This indicates that the omega defect model for L is reasonable on energetic grounds. It is shown further that the model is consistent in a number of respects with what is known about the I→II transition and L. Criteria for the occurrence of I→II transitions are presented, and the range of validity of the theory is discussed. It is noted that the I→II transition may be diffuse or absent in many cases, either because the equilibrium distribution is not attained or because the lifetime of the defects is too short in comparison with the residence time. Thus in many polymers, regime I may be missing so that regime II (with its locally rough growth front) will persist up to quite high temperatures, i.e., up to the practical limit of slow growth.     

Prediction of gas flow directions in gas assisted injection molding when cavities and runners are involved

In the prediction of gas flow-direction for gas-assisted injection molding (GAIM), the statement“Gas goes to the direction of the last area to fill with resin”, has been accepted as a correct one. When there exists more than one area to fill with resin, a mold design engineer for GAIM technologies has to determine to which direction gas goes that commercial software for GAIM (e.g., Moldflow) may be utilized for its mold design. However commercial software is generally expensive and is sometimes hard to become familiar with. As a rule of thumb, it is suggested that the resistance to the initial velocity of melt polymer at the nearest geometry to a gas injection point should be used as its criterion since gas goes in the direction of least resistance to initial resin-velocity. Neither the flow rate nor the resistance to flow rate can be a criterion in the prediction. Thus the statement“Gas goes to the direction of the least resistance to flow rates”, should be corrected to“More flow rate goes to the direction of the least resistance to flow rates.”, The rule of thumb suggested in this paper was verified by using commercial software, Moldflow, in the prediction of gas flow directions in GAIM under geometries where cavities and runners were involved. When the ratio of initial resin-velocity is so close to unity it is proposed as the adapted rule of thumb to calculate new emerging resin-velocities and resistances to resin-velocity at the first coming change of diameters in series of pipes and to compare those for upper and lower sides each other to predict the gas direction. Thus the judgment as to which point is the point where gas starts to choose a preferred direction is very important in the prediction.