It is habitual for combat sports athletes to lose weight rapidly to get into a lower weight class. Fluid restriction, dehydration by sweating (sauna or exercise) and the use of diuretics are among ...the most recurrent means of weight cutting. Although it is difficult to dissuade athletes from this practice due to the possible negative effect of severe dehydration on their health, athletes may be receptive to avoid weight cutting if there is evidence that it could affect their muscle performance. Therefore, the purpose of the present study was to investigate if hypohydration, to reach a weight category, affects neuromuscular performance and combat sports competition results.
We tested 163 (124 men and 39 woman) combat sports athletes during the 2013 senior Spanish National Championships. Body mass and urine osmolality (UOSM) were measured at the official weigh-in (PRE) and 13-18 h later, right before competing (POST). Athletes were divided according to their USOM at PRE in euhydrated (EUH; UOSM 250-700 mOsm · kgH2O(-1)), hypohydrated (HYP; UOSM 701-1080 mOsm · kgH2O(-1)) and severely hypohydrated (S-HYP; UOSM 1081-1500 mOsm · kgH2O(-1)). Athletes' muscle strength, power output and contraction velocity were measured in upper (bench press and grip) and lower body (countermovement jump - CMJ) muscle actions at PRE and POST time-points.
At weigh-in 84 % of the participants were hypohydrated. Before competition (POST) UOSM in S-HYP and HYP decreased but did not reach euhydration levels. However, this partial rehydration increased bench press contraction velocity (2.8-7.3 %; p < 0.05) and CMJ power (2.8 %; p < 0.05) in S-HYP. Sixty-three percent of the participants competed with a body mass above their previous day's weight category and 70 of them (69 % of that sample) obtained a medal.
Hypohydration is highly prevalent among combat sports athletes at weigh-in and not fully reversed in the 13-18 h from weigh-in to competition. Nonetheless, partial rehydration recovers upper and lower body neuromuscular performance in the severely hypohydrated participants. Our data suggest that the advantage of competing in a lower weight category could compensate the declines in neuromuscular performance at the onset of competition, since 69 % of medal winners underwent marked hypohydration.
Reactivity towards methanol and formic acid electrooxidation on Pt nanoparticles with well characterised surfaces were studied and compared with the behaviour of single crystal electrodes with basal ...orientations. Polyoriented and preferential (100), (111) and (100)-(111) Pt nanoparticles were synthesised, cleaned preserving its surface structure, characterised and employed to evaluate the influence of the surface structure/shape of the Pt nanoparticles on these two relevant electrochemical reactions. The results pointed out that, in agreement with fundamental studies with Pt single crystal electrodes, the surface structure of the electrodes plays an important role on the reactivity of both oxidation processes, and thus the electrocatalytic properties strongly depend on the surface structure/shape of the nanoparticles, in particular on the presence of sites with (111) symmetry. These findings open the possibility of designing new and better electrocatalytic materials using decorated shape-controlled Pt nanoparticles as previously described with Pt single crystal electrodes.
The kinetics of O
2 reduction on novel electrocatalyst materials deposited on carbon substrates were studied in 0.5
M H
2SO
4 and in 0.1
M NaOH solutions using the rotating disk electrode (RDE) ...technique. Pt nanoparticles (PtNP) supported on single-walled (PtNP/SWCNT) and multi-walled carbon nanotubes (PtNP/MWCNT) were prepared using two different synthetic routes. Before use, the CNTs were cleaned to minimize the presence of metal impurities coming from the catalyst used in the synthesis of this material, which can interfere in the electrochemical response of the supported Pt nanoparticles. The composite catalyst samples were characterised by transmission electron microscopy (TEM) showing a good dispersion of the particles at the surface of the carbon support and an average Pt particle size of 2.4
±
0.7
nm in the case of Pt/CNTs prepared in the presence of citrate and of 3.8
±
1.1
nm for Pt/CNTs prepared in microemulsion. The values of specific activity (SA) and other kinetic parameters were determined from the Tafel plots taking into account the real electroactive area of each electrode. The electrodes exhibited a relatively high electrocatalytic activity for the four-electron oxygen reduction reaction to water.
•Biodegradable potato starch/PVA/rosin blends were developed.•Addition of rosin to the blends improves mechanical properties substantially.•Mechanical properties are comparable to those offered by ...polymers such as LDPE.•Starch/PVA/rosin blends could be interesting materials for packaging applications.
Biodegradable potato starch/PVA samples containing different concentrations of rosin were prepared by melt-mixing in order to study the enhancement of the properties of native starch films. Glycerol and polyvinyl alcohol (PVA) are commonly used as plasticizers of starch. Their relatively low molecular weight (compared with starch) contributes to a good processability. Rosin is a renewable product whose incorporation in the starch/PVA matrix induces processing aid and reinforcing effects. Its relatively high molecular weight might prevent its migration to the surface of the final product. Water content, solubility in water, mechanical properties, microstructure and dynamic mechanical analysis of the samples were studied. The addition of 8% rosin to starch/PVA blends led to tensile strength values higher than 10 MPa and elongation at break values close to 2000%, values comparable to those offered by conventional polymers used in food packaging, for example LDPE. Furthermore, starch compounds have low cost and high biodegradability.
OBJECTIVESTo determine the prevalence of sarcopenia, frailty and cognitive impairment in elderly patients with nonvalvular atrial fibrillation (NVAF) and the factors' influence on survival. ...METHODSProspective, multicentre cohort study of patients older than 75 years with NVAF hospitalised in internal medicine departments in Spain. For each patient, we recorded the creatinine, haemoglobin and platelet levels, the scores on the CHA2DS2-VASc and HAS-BLED scales and Charlson index, as well as the use of oral anticoagulants. We measured sarcopenia with the SARC-F scale, frailty with the FRAIL scale and cognitive impairment with the Short Portable Mental State Questionnaire. We also conducted a 1-year follow-up. RESULTSThe study included 596 patients with NVAF, with a mean age of 84.9 (SD: 5.2) years. Of these, 295 (49.5%) presented sarcopenia, 305 (51.2%) presented frailty, and 251 (42.1%) presented cognitive impairment. At the end of 1year, 226 (37.9%) patients had died. Mortality was greater for the patients with sarcopenia, frailty and cognitive impairment. In the multivariate analysis, sarcopenia (HR: 1.775; 95%CI: 1.270-2.481), age, comorbidity and a history of peripheral embolism were associated with increased mortality, and the use of oral anticoagulants at discharge (HR: 0.415; 95%CI: 0.307-0.560) was associated with lower mortality. CONCLUSIONSSarcopenia, frailty and cognitive impairment are very common in elderly patients with NVAF and are frequently associated. Sarcopenia was associated with increased mortality.
García Pallarés, J, López-Gullón, JM, Torres-Bonete, MD, and Izquierdo, M. Physical fitness factors to predict female Olympic wrestling performance and sex differences. J Strength Cond Res ...26(3)794–803, 2012—To determine differences in anthropometric, body composition, physiological and neuromuscular markers between elite and amateur female wrestlers, 35 female wrestlers were assigned into 4 groups according to their body mass (light and middle weight) and their competitive level (elite and amateur)light weight (between 49 and 58 kg) in elite (n = 6) and amateur (n = 12) levels, and middle weight (between 58 and 67 kg) in elite (n = 7) and amateur (n = 10) levels. A binary logistic regression analysis was performed to identify which variables better predict female wrestling success. Elite female wrestlers were older (8–10%), had more training experience (27–29%), fat-free mass (3%), maximum strength in absolute and allometrically scaled values (13–33%), maximal muscle power (16–34%), mean and peak power during an arm crank Wingate testing in absolute and allometrically scaled values (17–23%), jumping height (2–9%) and grip (5–13%), and back isometric strength (10–13%) compared with amateur wrestlers (p < 0.05). When the results of the present research and those of a recent study performed in our laboratory with elite male wrestlers were compared, elite women presented lower (p < 0.05) maximum isometric and dynamic strength, muscle power output, and anaerobic metabolism values even when these data were normalized using allometric methods.
Abstract This study presents new ionanofluids (INF) composed of 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) and graphene oxide (GO) nanoparticles which have been assessed for the first time ...in an experimental flat plate solar thermal collector (FPSC). For this purpose, four types of INFs were synthesized, maintaining a constant concentration of GO nanoparticles dispersed in different base fluids: ionic liquid (IL/GO), a mixture of ionic liquid and water in varying concentrations (IL-water (75–25)%/GO and IL-water (50–50)%/GO), and water (Water/GO). These four INFs were characterized and their thermophysical and physicochemical properties were determined. The results indicated a 37.4% improvement in efficiency and up to a 2.5-fold increase in temperature within the collector when the IL was applied exclusively as the base fluid, compared to water. Furthermore, IL/GO demonstrated excellent stability, showing no signs of deterioration or nanoparticle precipitation two years after preparation and testing. These findings suggest that INFs based on IL and GO nanoparticles significantly enhance the efficiency of FPSC, presenting a promising option for solar energy applications and opening a new research avenue for INFs in the production of domestic hot water.
Starch films are gaining attention as substitutes of synthetic polymers due to their biodegradability and low cost. Some ionic liquids have been postulated as alternatives to glycerol, one of the ...best starch plasticizers, due to their great capacity to form hydrogen bonds with starch and hence great ability of preventing starch retrogradation and increasing film stability. In this work, emim+Ac−-plasticized starch films were prepared from potato, corn and wheat starch. The effect of starch molecular structure in terms of granular composition (amylose and phosphate monoester contents) and molecular weight (Mw) on film properties was evaluated. Potato starch films were the most amorphous because of the higher Mw and phosphate monoester content of potato starch, both contributing to a lower rearrangement of the starch chains making the crystallization process difficult. In contrast, corn and wheat starches lead to more crystalline films because of their lower Mw, which may imply higher mobility and crystal growth rate, and lower phosphate monoester content. This more crystalline structure could be the responsible of their better mechanical properties. emim+Ac− can be considered suitable for manufacturing starch films showing corn and wheat starch films similar properties to synthetic low-density polyethylene, but involving a simple and environmentally-friendly process.
OBJECTIVETo determine the prognostic value of myocardial perfusion scintigraphy-gated SPECT in patients with diabetes mellitus and without obstructive coronary artery disease. MATERIALS AND ...METHODSThis retrospective study included consecutive patients undergoing adenosine stress-rest myocardial perfusion imaging (MPI) by 99mTc-tetrofosmin between 2009 and 2011. The patients had diabetes mellitus and coronary angiography without significant coronary lesions. In total, 37 diabetic patients (female/male: 20/17; mean age: 65.2 (range: 40-78). 29 non-diabetic patients were included wich are matched with the group of diabetic patients with positive MPI. The group of non-diabetic patients had scintigraphy with myocardial ischemia and without angiographic lesions. A 36-month clinical follow-up was performed, and major cardiac events were recorded. RESULTSIn 78.3% (29/37) of diabetic patients the scintigraphic study showed myocardial ischemia, while it was negative in the 21.7%. The cardiac event rate in both groups was 6%. In diabetics with a myocardial perfusion study with myocardial ischemia, there were 3 major cardiac events. In diabetic patients with negative study had no cardiac event. In the non-diabetic control group the cardiac events rate was 3.4% (1/29). CONCLUSIONIn diabetic patients without obstructive coronary disease, myocardial perfusion study can be predictor of cardiac events. A negative study can be an indicator of a better cardiovascular prognosis.
The search for food resources is a constant in human history. Nowadays, the search for natural and safe food supplies is of foremost importance. Accordingly, there is a renewed interest in ...eco-friendly and natural products for substitution of synthetic additives. In addition, microbial contamination of food products during their obtaining and distribution processes is still a sanitary issue, and an important target for the food industry is to avoid food contamination and its related foodborne illnesses. These diseases are fundamentally caused by certain microorganisms listed in this review and classified according to their Gram negative or positive character. Algae have proven to possess high nutritional value and a wide variety of biological properties due to their content in active compounds. Among these capabilities, macroalgae are recognized for having antimicrobial properties. Thus, the present paper revises the actual knowledge of microbial contaminants in the food industry and proposes antimicrobial algal compounds against those pathogenic bacteria responsible for food contamination as valuable molecules for its growth inhibition. The capacity of algae extracts to inhibit some major food pathogen growth was assessed. Moreover, the main applications of these compounds in the food industry were discussed while considering their favorable effects in terms of food safety and quality control.
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