Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test

Background

Dietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20?g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1?±?5.8?years old) immediately before and 5 and 60?min after the exhaustive Wingate test.

Results

Maximum anaerobic power was improved by acute creatine supplementation (10.5?%), but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP), leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects.

Conclusions

Our data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent) and inherent antioxidant activity of creatine.     

Large‐scale heat exchanger networks synthesis using simulated annealing and the novel rocket fireworks optimization

Heat Exchanger Network (HEN) synthesis is an important field of study in process engineering. However, obtaining optimal HEN design is a complex task. When mathematically formulated, it may require sophisticated methods to achieve good solutions. The complexity increases even more for large‐scale HEN. In this work, a hybrid meta‐heuristic method is presented. A rather simple Simulated Annealing approach is used for the combinatorial level, while a strategy named rocket fireworks optimization is developed and applied to the continuous domain. An advantage over other approaches is that the algorithm was written in C++, which is free and faster when compared to many other languages. The developed method was able to provide the lowest costs solutions reported so far to six cases well studied in the literature. An important feature of the approach here proposed is that, differently from other approaches, it does not split HEN into smaller problems during the optimization. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1582–1601, 2017     

The silicon neighborhood across the a-Si:H to μc-Si transition by X-ray absorption spectroscopy (XAS)

We report a synchrotron X-ray absorption spectroscopy study of the average neighborhood of Si near the transition from a-Si:H to μc-Si on wedge-shaped samples prepared by hot-wire CVD in a chamber using a movable shutter. The thickness of the wedge varies from 30 to 160 nm. Nucleation of μc-Si occurs at a critical thickness of approximately 100 nm. X-Ray absorption was measured at the Si K-edge (1.84 keV) by total electron photoemission yield. The absorption oscillations in the EXAFS region are very similar to all along the wedge. Analysis indicates an average tetrahedral first neighbor shell with radial disorder decreasing with crystallization. In the near-edge (XANES) region multiple scattering effects appear at the onset of crystallinity. Unlike single crystal silicon, these effects involve only double scattering within the first neighbor shell, indicating an ill-formed second shell in μc-Si.     

Efficient annotation of vesicle dynamics video microscopy

We describe an algorithm for the efficient annotation of events of interest in video microscopy. The specific application involves the detection and tracking of multiple p ossibly overlapping vesicles in total internal reflection fluorescent microscopy images. A st atistical model for the dynamic image data of vesicle configurations allows us to properly weight various hypotheses online. The goal is to find the most likely trajectories given a sequence of images. The computational challenge is addressed by defining a sequence of coarse-to-fine tests, derived from the statistical model, to quickly eliminate most candidate positions at each time frame. The computational load of the tests is initially very low and gradually in creases as the false positives become more difficult to eliminate. Only at the last step, state variables are estimated from a complete time- dependent model. Processing time thus mainly depends on the number of vesicles in the image and not on image size.     

Intrasphincteric injection of botulinum toxin is effective in long-term treatment of esophageal achalasia

We investigated the long-term efficacy and safety of intrasphincteric injections of botulinum toxin (100 U) in 57 patients with esophageal achalasia. One month after treatment, 50 patients had improved (88%); both symptom score and LES pressure were significantly reduced (P < 0.001). After a mean follow-up of 24+/-15 months (range 6-48), 43 patients (75%) are still in remission, although repeat injections of toxin were needed to achieve a stable effect on symptoms.     

Formation of new stable pigments from condensation reaction between malvidin 3-glucoside and (−)-epicatechin mediated by acetaldehyde: Effect of tartaric acid concentration

The objective of this work was to study the effect of tartaric acid concentration on the condensation reaction between malvidin 3-glucoside (Mv-glc) and flavanols mediated by acetaldehyde in the model solution. The model wine solutions were prepared by 12% ethanol in water (v/v) with two different l-tartaric acid concentrations (5 g/l and 25 g/l, respectively) and at two different pH values (3.2 and 1.7, respectively). Four new pigments were detected in model wine solutions containing Mv-glc, (−)-epicatechin and acetaldehyde. By reverse-phase HPLC-DAD, ESI-MS and MSⁿ fragmentation analysis, the four new pigments were tentatively identified as four isomers of hydroxyethyl malvidin-3-glucoside-ethyl-flavanol. The decrease in the concentration of Mv-glc and (−)-epicatechin and the increase in the concentration of the new identified pigments were more pronounced at higher tartaric acid concentration. At pH 1.7, although the two well-recognized ethyl-linked Mv-glc-flavanol isomers were quantitatively the major pigmented products in the reaction solution throughout the assay period, they appeared less stable than the four new pigments. At pH 3.2, the rate of formation of ethyl-linked Mv-glc-flavanol pigments was much slower than at pH 1.7, whereas the four new pigments were quantitatively the predominant pigmented products at the latter stage of the reaction.     

Spurious results of the component mode synthesis

The natural frequencies and mode shapes of a bentbeam in flexure-torsion oscillation are examined using the modal synthesis technique. The problem involves six boundary constraint conditions and the effect of ignoring a number of these conditions are examined. The choice of generalized coordinates offer other variations in the problem. In all, 50 different cases are studied on the digital computer. These are compared with the exact solution and also with experimental results obtained in the laboratory.     

Development of Non-reactive F-Free Mold Fluxes for High Aluminum Steels: Non-isothermal Crystallization Kinetics for Devitrification

Metallurgical and Materials Transactions B - It is necessary to study crystallization from glass (devitrification) for non-reactive F-free CaO-Al2O3 based mold fluxes; this is especially important...     

New insight about the relationship between the main characteristics of precursor materials and activated carbon properties using multivariate analysis

Agro-industrial wastes are used as carbon precursors in the production of activated carbon because they are rich in lignocellulosic materials. This study aimed to investigate the relationship between the main characteristics of precursor materials and activated carbons by multivariate analysis. After characterization of the precursor materials and their respective carbons, the principal component analysis and canonical correlation analysis were performed. Materials with cellulose/lignin ratio > 3.0 led to the production of carbons with a higher pore diameter, while materials with a cellulose/lignin ratio ≤ 1.0 led to a low pore volume. Using the mathematical models obtained, it is possible to predict the carbon characteristics using only the composition data of the lignocellulosic materials.