Search

The use of neonicotinoid insecticides leads to environmental problems such as accumulation and death of different insects and even bird species. In this work, we compared the SERS performance of Ag nanocubes- and nanospheres-based substrates for the analysis of thiacloprid, a neonicotinoid, reaching its detection at 1 mM using nanocubes as the active material.

La Gran Guerra, aunque enfrentó al principio a potencias europeas, comprendió un escenario mundial, tuvo un primer episodio en África y también alcanzó al océano Pacífico. Mediante una metodología de investigación en la que se recurre a fuentes documentales primarias y, cuando resultare imposible, a trabajos de autores o informaciones que testimonien una evidencia, se ha logrado analizar el papel que tuvieron (a pesar de ser neutrales) dos países iberoamericanos ribereños del océano Pacífico: Chile y México. El primero con la contienda frente al puerto de Coronel entre la flota alemana y la Royal Navy de Reino Unido en aguas territoriales chilenas. Mientras que México desempeñó un papel muy importante de forma pasiva al mantenerse neutral respecto a Alemania y Estados Unidos. La riqueza del artículo radica en examinar varios acontecimientos muy poco conocidos producidos en la cuenca del océano Pacífico durante la Primera Guerra Mundial y el papel desempeñado por estas dos naciones iberoamericanas.

Del Coso, J, Salinero, JJ, Lara, B, Gallo-Salazar, C, Areces, F, Herrero, D, and Puente, C. Polygenic profile and exercise-induced muscle damage by a competitive half-ironman. J Strength Cond Res 34(5): 1400-1408, 2020-To date, it is still unknown why some individuals develop higher levels of muscle damage than other individuals, despite participating in exercise with comparable levels of physical intensity. The aim of this investigation was to analyze 7 single-nucleotide polymorphisms (SNPs) that are candidates to explain individual variations in the level of muscle damage attained during a half-ironman competition. Using the model of Williams and Folland (2, 1, and 0 points for optimal, intermediate, and suboptimal genotype), we determined the total genotype score from the accumulated combination of 7 SNPs (ACE = 287bp Ins/Del; ACTN3 = p.R577X; creatine kinase, muscle type = NcoI; insulin-like growth factor 2 = C13790G; interleukin-6 = 174G>C; myosin light chain kinase = C37885A; and tumor necrosis factor-α = 308G>A) in 22 experienced triathletes. Before and after the race, a sample of venous blood was obtained to measure serum markers of muscle damage. Two groups of triathletes were established according to their postcompetition serum CK concentration: low CK responders (n = 10; 377 ± 86 U·L) vs. high CK responders (n = 12; 709 ± 136 U·L). At the end of the race, low CK responders had lower serum myoglobin concentrations (384 ± 243 vs. 597 ± 293 ng·ml, p = 0.04). Although the groups were similar in age, anthropometric characteristics, and training habits, total genotype score was higher in low CK responders than in high CK responders (7.7 ± 1.1 vs. 5.5 ± 1.1 point, p < 0.01). A favorable polygenic profile can contribute to reducing the level of muscle damage developed during endurance exercise.

Resumen El presente artículo expone la evolución del proceso de independencia de los territorios de las colonias del Imperio español en América Central. No solo se sugiere la influencia de las ideas liberales en Europa, procedentes de la Revolución Francesa de 1789, sino también el ejemplo de la independencia de Estados Unidos. El proceso independentista en Centroamérica fue un movimiento pacífico en contraste con los enfrentamientos militares con las tropas realistas de la monarquía española en otras regiones. Se relata la importancia de la participación de militares y políticos en la lucha por la independencia, pero también del estamento religioso más básico, es decir de los curas. Para ello, se acude a los textos de las Actas de independencia de 1821 y de 1823 y al Acta de la Anexión de Centroamérica al Imperio mexicano para valorar el papel que desempeñó la voluntad popular durante el proceso emancipador frente a la influencia de otros Estados. Una reflexión sobre la influencia de la política de Estados Unidos y, en particular, de la Doctrina Monroe, marca la diferencia entre independencia y soberanía en el proceso independentista de las provincias centroamericanas. La importancia geopolítica de la región atrajo el interés no solo de las potencias europeas, en particular de Gran Bretaña, sino también de Estados Unidos durante el período que ocupa este artículo. La inestabilidad política, económica y social que siguió al proceso de independencia fue aprovechada por el gigante estadounidense para obtener una vía que permitiera la comunicación entre las costas del Atlántico y del Pacífico, lo que contribuía con la expansión de un nuevo imperialismo. Abstract The main target of the article is to understand the evolution of the independence process of the colonies of the Spanish Empire in Central America. It is suggested not only the influence of liberal ideas from Europe after the French Revolution of 1789 but also the example of the independence of the United States. The independence process in Central America was a peaceful movement in contrast to the military confrontations with the royalist troops of the Spanish Monarchy elsewhere. The importance of the participation of the military and politicians in the struggle for independence is underlined, but the participation of the most basic religious establishment, the priests, was of great importance. The legal texts of the Independence Acts of 1821 and 1823 and the Act of the Annexation of Central America to the Mexican Empire are used to assess the role played by the popular will during the independence process against the influence of other foreign States. A reflection on the influence of the United States foreign policy and, especially, of the Monroe Doctrine marks the difference between independence and sovereignty in the independence process of the Central American provinces. The geopolitical importance of the region attracted the interest not only of the European powers, especially Great Britain, but also the United States during the period covered by this article. The political, economic, and social instability that followed the independence process was used by the North American giant to open a waterway that would allow the communication between the Atlantic and Pacific coasts, contributing to the expansion of a new kind of imperialism.

The Pacific Ocean was integrated into the global economy when it was possible to travel from the Philippines Islands to New Spain, thanks to the navigator and explorer Andres de Urdaneta. The Ocean discovered by Nunez de Balboa in 1513 and explored by the Magallanes-Elcano expedition, in its circumvallation of the Earth, between 1519-1522, focused the interest of other European powers in the 17th and 18th centuries that, until then it was just a Spanish sea. Dutch, British, Russians, Americans and finally French colonialism transformed the Ocean into the geopolitical core of their colonial disputes and their mercantilist interests. This situation was possible due to the existence of a weak Chinese Empire, where the colonial powers established their areas of influence for decades, and an isolated Japan with its medieval status, which used Western influences to become a great empire with expansionist purposes. The German Empire had little influence on the Pacific Ocean. This article shows that, at the end of the 19th century, the collapse of the Spanish Empire gave way to the new American imperialism and it was the origin of the influence of United States of America in the Pacific Ocean and transformed it into the geopolitical and geoeconomic center of gravity of the new world order.

espanolLas organizaciones constituyen un sistema socio-tecnico integrado dentro de un contexto socioeconomico y politico, el analisis de su interaccion en el tiempo es la propuesta de este articulo, enfocado en el analisis del caso de una industria en la cual en los ultimos anos ha existido una dinamica intensa. OBJETIVO. Determinar dimensiones especificas de analisis en una compania del sector de energia en el Ecuador durante un periodo. METODO. El analisis de caso como herramienta de vinculo entre la teoria y el pragmatismo organizacional. RESULTADOS. Las dimensiones al interior del espacio organizacional son: estructura organizacional, personas y cultura, procesos y sistemas de innovacion, mientras que las externas son: relaciones externas y contexto organizacional. DISCUSION Y CONCLUSIONES. La integracion cultural se ve afectada por la falta de comunicacion, especialmente cuando se dan procesos de fusiones o adquisiciones, en este sentido los procesos deben considerar sistemas estructurados de seguimiento, control y division del trabajo bajo niveles definidos de descentralizacion en funcion de la especialidad del conocimiento, con el apoyo de normativa que promueva la innovacion y la sistematizacion de la informacion. Desde el analisis endogeno el contexto debe ser establecido con una vision global y por su parte las relaciones externas se definen como un factor de sostenibilidad en el largo plazo. EnglishThe organizations constitute an integrated socio-technical system within a socioeconomic and political context, the analysis of their interaction in a period of time is the proposal of this article for an intense dynamic industry in the last years of operation. OBJECTIVE. Determine specific analytic dimensions for a company in the energy sector in Ecuador during a period of time. METHOD. The case analysis as a tool to link theory and organizational pragmatism. RESULTS The dimensions within the organizational space are: organizational structure, people and culture, processes and innovation systems, the external dimensions are: external relations and organizational context. DISCUSSION AND CONCLUSIONS. Cultural integration is affected by the lack of communication, especially when there are mergers or acquisitions, in this sense the processes must consider structured monitoring systems, control over the work task division under defined levels of decentralization depending on the knowledge specialization, with the support of the regulations could promote innovation and the information systematization. From the endogenous analysis the context must be established with a global vision and the external relations are defined as a factor of long term organizational sustainability.

In this paper, we present a greener synthesis of silver and gold nanoparticles using an aqueous extract of Ficus benjamina leaves. The metal nanoparticles were synthesized via conventional heating and microwave-assisted methods using the aqueous extract as reducing and capping agent. It was observed that the use of a Ficus benjamina leaf aqueous extract via microwave-assisted heating represent a faster, greener and easier method than a conventional heating procedure for the synthesis of silver and gold nanospheres , also leading to narrower nanoparticle size. The sensing characteristics of the microwave-assisted silver nanoparticles were evaluated for the specific determination and semiquantification of Zn(II) ions. The colorimetric semiquantification of Zn(II) ions was achieved by UV–vis spectroscopy, using an empirical model in a concentration range between 0.2 and 2.0 mM, reaching total precipitation at concentrations higher than 2.0 mM.

The plasmonic nanomaterials consist of coinage materials with at least one dimension at the nanometric scale. Silver and gold are the most used plasmonic materials; however, nanoparticles based on copper, aluminum, and even carbon can show a plasmonic behavior. Nevertheless, the common use of silver and gold resides on their chemical stability, their ease of obtainment, and the fact that their optical properties occur at ultraviolet-visible-near infrared wavelengths. To obtain nanoparticle dispersions with uniform and reproducible properties, the study of different synthesis methods became a research area that must be highlighted. This opens the door for the research of bottom-up syntheses, mainly including chemical reactions. The dispersity of the chemically obtained dispersions is balanced with the reaction cost; but with a new solution, old and new problems arise: the use of expensive reagents and the environment pollution due to undesired products treatment and disposal. The new challenge of obtaining nanoparticles with less or no environmental impact and a high monodispersity rapidly became the concern of nanomaterial researchers, and one of the potential alternatives were the biological synthesis methods. Among the different ways to obtain nanomaterials by taking advantage of the biology, the plant-mediated procedures offer a great alternative. One of the main advantages of these techniques is the capability of using any part of the plant as a reagent and being able to obtain different morphologies. In this chapter, the chemistry behind the plant-mediated synthesis of plasmonic nanomaterials, the different plant tissues and products that can be used, the formation and growth of different nanomorphologies, and some of the works achieved in this area, will be reviewed to give the reader a tool for a greener obtainment of plasmonic nanostructures.

Las fusiones entre competidores son una práctica empresarial común que genera importantes consecuencias para el mercado, una de ellas es la concentración económica, que puede perjudicar la libre competencia a corto, mediano y largo plazo. En Ecuador el mercado cervecero es un interesante eje de estudio, pues constituye un mercado altamente concentrado, con pocos participantes y en él, la Superintendencia de Control de Poder de Mercado estableció las condiciones para la fusión entre dos de sus participantes más relevantes: Cervecería Nacional (SABMiller) y Ambev (Anheuser-Busch Inbev). Este artículo analiza la concentración económica del sector cervecero ecuatoriano y los efectos de la fusión entre éstos dos competidores. Es un estudio cuali - cuantitativo en el cual se evaluaron las características del sector cervecero ecuatoriano y las condiciones de la fusión efectuada, para determinar, a través de indicadores de concentración y datos de volúmenes de venta del sector entre 2013 y 2015- cuáles son los niveles de concentración y posibles tendencias en cuanto a la oferta y comportamiento de dicho sector; demostrándose que existe un mercado altamente concentrado, con un índice de Herfindahl superior a 9000, y con condiciones que nublan la posibilidad de competencia en el mercado a corto plazo. AbstractMergers between competitors are a common business practice that generates important consequences for the market, one of them is economic concentration, which can affect the free competition in the short, medium and long term. In Ecuador, the beer market is an interesting area of study, since it represents a highly concentrated market, with few participants in which the Superintendence of Market Power Control has established the conditions for the merger between two of its most relevant participants: National Brewery (SABMiller) and Ambev (Anheuser-Busch Inbev). This article analyzes the economic concentration of the Ecuadorian beer sector and the effects of the merger between these two competitors. This research is a qualitative-quantitative study in which the characteristics of the Ecuadorian beer sector and the conditions of the merger were evaluated, to determine the levels of concentration and possible trends in the supply and behavior of this sector by using concentration indicators and data of sales volumes between 2013 and 2015. That showed that there is a highly concentrated market, with a Herfindahl index above 9000, and with conditions that null the possibility of short-term market competition.

Puente, C, Abián-Vicén, J, Areces, F, López, R, and Del Coso, J. Physical and physiological demands of experienced male basketball players during a competitive game. J Strength Cond Res 31(4): 956-962, 2017-The aim of this investigation was to analyze the physical and physiological demands of experienced basketball players during a real and competitive game. Twenty-five well-trained basketball players (8 guards, 8 forwards, and 9 centers) played a competitive game on an outdoor court. Instantaneous running speeds, the number of body impacts above 5 g, and the number of accelerations and decelerations were assessed by means of a 15-Hz global Positioning System accelerometer unit. Individual heart rate was also recorded using heart rate monitors. As a group mean, the basketball players covered 82.6 ± 7.8 m·min during the game with a mean heart rate of 89.8 ± 4.4% of maximal heart rate. Players covered 3 ± 3% of the total distance running at above 18 km·h and performed 0.17 ± 0.13 sprints per minute. The number of body impacts was 8.2 ± 1.8 per minute of play. The running pace of forwards was higher than that of centers (86.8 ± 6.2 vs. 76.6 ± 6.0 m·min; p ≤ 0.05). The maximal speed obtained during the game was significantly higher for guards than that for centers (24.0 ± 1.6 km·h vs. 21.3 ± 1.6 km·h; p ≤ 0.05). Centers performed a lower number of accelerations/decelerations than guards and forwards (p ≤ 0.05). In conclusion, the extraordinary rates of specific movements performed by these experienced basketball players indicate the high physiological demands necessary to be able to compete in this sport. The centers were the basketball players who showed lower physiological demands during a game, whereas there were no differences between guards and forwards. These results can be used by coaches to adapt basketball training programs to the specific demands of each playing position.

In this study, silver nanoparticles (NP) were synthesized by two methods: using an aqueous extract of Mentha spicata leaves and using citrate ions as stabilizing agent, and the cytotoxicity and anticancer activity of both NP were evaluated in vitro. The particles synthesized with the aqueous extract were spherical with a size ranging from 15 to 45 nm. These NP decreased cell viability in all of the cells studied; however, the IC50 could only be estimated in the Chang liver cells (IC50 = 21.37 µg/mL). These particles also decreased the generation of reactive oxygen species in Chang and SiHa cells. Additionally, the dispersions decreased the activity of caspase-3. There was no significant difference between the biological activities of the NP obtained with the aqueous extract and the NP synthesized using citrate ions. This study showed that an aqueous extract of M. spicata is an excellent alternative for the synthesis of silver NP. These NP showed cytotoxicity and anticancer activity in vitro. Although more experiments are required, the cell death occurs probably through a mechanism different from apoptosis.

Success rate in replantation/revascularization digital surgery is one of the challenges of reconstructive surgery. For this reason, investigating prognostic factors for survival and improvement of outcomes is highly relevant. The goal of this study was to establish predictive factors of survival in replantation/revascularization digital surgery. A descriptive, retrospective study was performed in patients who underwent urgent replantation/revascularization digital surgery in our center between January 2007 and July 2017. A total of 116 patients and 157 digits were included. Outcome (survival) factors evaluated were: preoperatively: age, sex, body mass index (BMI), ASA anesthesia score, comorbidities (smoking status, diabetes mellitus, hypertension), coagulation, type of lesion, number of affected digits, position of affected digits, injury mechanism, ischemia time; time between accident and the surgery; intraoperatively: anesthetic technique, fluid therapy (administered volume), length of surgery; and postoperatively: post-surgical complications, re-intervention requirements, surgical success rate. Statistical analysis was performed to evaluate outcome and elicit predictive factors. 157 digits from a total of 116 patients were included. Statistically significant differences regarding predictors of survival of replantation were found in ischemia time (0 0.003), length of surgery (p 0.004), post-surgical complications (p 0.000) and replantation need (p 0.000). The rest of analyzed variables were not statistically significant (p > 0.05). Revascularization surgery had a greater success rate than replantation (p 0.001). Success rate in traumatic digital surgery is greater when revascularization surgery is performed, rather than replantation. Preoperative ischemia time, length of surgery, postoperative complications and re-intervention requirement are the factors that affect survival rate.

Exercise-induced muscle damage has been identified as one of the main causes of the progressive decrease in running and muscular performance in marathoners. The aim of this investigation was to determine the influence of the ACTN3 genotype on exercise-induced muscle damage produced during a marathon. Seventy-one experienced runners competed in a marathon race. Before and after the race, a sample of venous blood was obtained and maximal voluntary leg muscle power was measured during a countermovement jump. In the blood samples, the ACTN3 genotype (R577X) and the changes in serum creatine kinase and myoglobin concentrations were measured. Data from RX heterozygotes and XX mutant homozygotes were grouped as X allele carriers and compared to RR homozygotes. At the end of the race, X allele carriers presented higher serum myoglobin (774 ± 852 vs 487 ± 367 U L−1; P = 0.02) and creatine kinase concentrations (508 ± 346 vs 359 ± 170 ng mL−1; P = 0.04) than RR homozygotes. Pre-to-post-race maximal voluntary leg muscle power reduction was more pronounced in X allele carriers than RR homozygotes (−34.4 ± 16.1 vs −27.3 ± 15.4%; P = 0.05). X allele carriers self-reported higher levels of lower limb muscle pain (7 ± 2 vs 6 ± 2 cm; P = 0.02) than RR homozygotes at the end of the race. In comparison to RR homozygotes, X allele carriers for the R577X polymorphism of the ACTN3 gene presented higher values for typical markers of exercise-induced muscle damage during a competitive marathon. Thus, the absence of a functional α-actinin-3 produced by the X allele might induce higher levels of muscle breakdown during prolonged running events. Universidad Camilo José Cela (Proyecto DAMUS) 2.401 JCR (2017) Q2, 27/81 Sport sciences; Q3, 45/83 Physiology 1.186 SJR (2017) Q1, 435/2878 Medicine (miscellaneous), 37/285 Orthopedics and Sports Medicine, 80/554 Public Health, Environmental and Occupational Health, 29/127 Sports Science; Q2, 36/107 Physiology (medical) No data IDR 2017 UEM

The search for cost-effective methods for the fabrication of sensitive and selective surface-enhanced Raman spectroscopy (SERS) substrates has led to recent studies exploring the incorporation of biopolymers as the supporting scaffold or nanostructure stabilizer. In this paper, we report on the effect of the enhancing nanostructure morphology on the SERS performance of chitosan-containing substrates. For this work, silver nanospheres, silver nanocubes, gold nanospheres, and gold nanorods were synthesized and fully characterized; then, SERS substrates were prepared using all of the morphologies and chitosan with varying concentrations and molecular weight to also test the effect of the biopolymer on the SERS effect. This work showed that the chitosan film allows for trapping of analyte molecules and thus, higher Raman intensities. It was found that the chitosan concentration plays an important role in this effect. The fabricated substrates showed minimum values of detected concentration between 10−4 and 10−9 M using p-ATP as probe molecule, depending on the nanostructure morphology used, showing that the silver nanocubes lead to a higher sensitivity and Raman intensities enhancement compared to the other dispersions studied.

2D printing is a commonly used technology based on the addition of dots onto a flat surface with X and Y axis. 3D printing, on the other hand, is related to additive manufacturing by adding layer by layer of the raw material fed into it to create a final product; in other words, it adds another dimension of depth, that is to say, a Z axis. 3D printing applications are revolutionary when compared to 2D because it is possible to create a complex object in numerous possible materials. Recently, the use of nanomaterials in 3D printing technology has gained attention, especially the synthesis of nanostructured dispersions also called nanoinks, which are used as building material in the additive manufacture process. The incorporation of nanomaterials in 3D printing techniques has allowed the introduction of materials for new generation devices with specific electrical, optical, and mechanical properties. 3D printing has been used to create nanoengineering prototypes; they have the potential to optimize the resources in fields like reconstructive medicine, electronic circuits, and scaffolds fabrication, among others. 3D printing technology has already been proved as a viable alternative in several medical applications including the manufacture of custom prosthetic devices, dental implants, and even the first steps in organs and tissues printing. In circuit fabrication, printable conducting inks, such as metals and conductive polymers, have been widely studied allowing the fabrication of flexible electric circuits and chemical sensors. Furthermore, the use of 3D printing technology is often supported in scaffolds, which provides, mainly, mechanical and electrical properties to the final composite. The development of new inks based on nanomaterials often encounters different obstacles, such as controlling the ink viscosity and surface tension, which are important parameters in the printing process.

The electrolytic oxidation of a metal anode in a solvent containing the ligand of interest is a single-step process for the synthesis of metal complexes. This method allows the formation of both coordination complexes and organometallic compounds. The direct electrochemical synthesis of metal complexes is a simple technique, often carried out at room temperature, which allows us to choose from a variety of ligands. The electrolytic oxidation of the metal avoids the use of oxidizing agents; therefore there are no species that could compete with the ligand to coordinate with the metal ion. The electrosynthesis can be kinetically controlled by adjusting the intensity of the current through the cell, if the reduced metal ions are generated slowly.

The aim of this study was to determine the effect of caffeine intake on overall basketball performance in experienced players. A double-blind, placebo-controlled, randomized experimental design was used for this investigation. In two different sessions separated by one week, 20 experienced basketball players ingested 3 mg of caffeine/kg of body mass or a placebo. After 60 min, participants performed 10 repetitions of the following sequence: Abalakov jump, Change-of-Direction and Acceleration Test (CODAT) and two free throws. Later, heart rate, body impacts and game statistics were recorded during a 20-min simulated basketball game. In comparison to the placebo, the ingestion of caffeine increased mean jump height (37.3 ± 6.8 vs. 38.2 ± 7.4 cm; p = 0.012), but did not change mean time in the CODAT test or accuracy in free throws. During the simulated game, caffeine increased the number of body impacts (396 ± 43 vs. 410 ± 41 impacts/min; p < 0.001) without modifying mean or peak heart rate. Caffeine also increased the performance index rating (7.2 ± 8.6 vs. 10.6 ± 7.1; p = 0.037) during the game. Nevertheless, players showed a higher prevalence of insomnia (19.0 vs. 54.4%; p = 0.041) after the game. Three mg of caffeine per kg of body mass could be an effective ergogenic substance to increase physical performance and overall success in experienced basketball players.

Previous investigations have determined that some individuals have minimal or even ergolytic performance effects after caffeine ingestion. The aim of this study was to analyze the influence of the genetic variations of the CYP1A2 gene on the performance enhancement effects of ingesting a moderate dose of caffeine. In a double-blind randomized experimental design, 21 healthy active participants (29.3 ± 7.7 years) ingested 3 mg of caffeine per kg of body mass or a placebo in testing sessions separated by one week. Performance in the 30 s Wingate test, visual attention, and side effects were evaluated. DNA was obtained from whole blood samples and the CYP1A2 polymorphism was analyzed (rs762551). We obtained two groups: AA homozygotes (n = 5) and C-allele carriers (n = 16). Caffeine ingestion increased peak power (682 ± 140 vs. 667 ± 137 W; p = 0.008) and mean power during the Wingate test (527 ± 111 vs. 518 ± 111 W; p < 0.001) with no differences between AA homozygotes and C-allele carriers (p > 0.05). Reaction times were similar between caffeine and placebo conditions (276 ± 31 vs. 269 ± 71 milliseconds; p = 0.681) with no differences between AA homozygotes and C-allele carriers. However, 31.3% of the C-allele carriers reported increased nervousness after caffeine ingestion, while none of the AA homozygotes perceived this side effect. Genetic variations of the CYP1A2 polymorphism did not affect the ergogenic effects and drawbacks derived from the ingestion of a moderate dose of caffeine.

Alpha-actinin-3, encoded by the ACTN3 gene, is an actin-binding protein with an important role in myofibril contraction and muscle force output. In humans, there is a relatively common deficiency of the α-actinin-3 due to homozygosity in a polymorphism of the ACTN3 gene (R577X, rs1815739), that has been related to decreased resistance to strain during voluntary muscle contractions. The purpose of this study was to investigate the influence of the ACTN3 genotype on the level of exercise-induced muscle damage attained by 23 experienced triathletes during an official half-ironman competition. Before and after the race, a sample of venous blood was obtained and jump height was measured during a countermovement jump. The changes in serum creatine kinase (CK-MM isoform) were measured in the blood samples and muscle pain was measured with a visual analogue scale (0–10 cm). Data from RX heterozygotes and XX mutant homozygotes were grouped as X-allele carriers (n = 13) and compared to RR homozygotes (n = 10). Race time was very similar between groups (313 ± 31 vs. 313 ± 25 min; P = 0.45); however, pre-to-post-competition reduction in jump height was greater in X-allele carriers than RR homozygotes (−18.4 ± 11.4 vs. −8.2 ± 6.9%; P = 0.04). At the end of the race, X-allele carriers presented higher serum CK-MM concentrations (682 ± 144 vs. 472 ± 269 U/L; P = 0.03), and there was also a tendency for higher self-reported values of lower limb muscle pain (7.7 ± 1.1 vs. 6.3 ± 2.3 cm; P = 0.06). X-allele triathletes in the ACTN3 R577X polymorphism presented greater signs of exercise-induced muscle damage during a half-ironman race than RR homozygotes.

Background: Sodium (Na+) intake during exercise aims to replace the Na+ lost by sweat to avoid electrolyteimbalances, especially in endurance disciplines. However, Na+ needs can be very different among individuals because of the great inter-individual variability in sweat electrolyte concentration. The aim of this investigation was to determine sweat electrolyte concentration in a large group of marathoners. Methods: A total of 157 experienced runners (141 men and 16 women) completed a marathon race (24.4 ± 3.6 °C and 27.7 ± 4.8 % of humidity). During the race, sweat samples were collected by using sweat patches placed on the runners’ forearms. Sweat electrolyte concentration was measured by using photoelectric flame photometry. Results: As a group, sweat Na+ concentration was 42.9 ± 18.7 mmol·L−1 (minimal-maximal value = 7.0–95.5 mmol·L−1), sweat Cl− concentration was 32.2 ± 15.6 mmol·L−1 (7.3–90.6 mmol·L−1) and sweat K+ concentration was 6.0 ± 0.9 mmol·L−1 (3.1–8.0 mmol·L−1). Women presented lower sweat Na+ (33.9 ± 12.1 vs 44.0 ± 19.1 mmol·L−1; P = 0.04) andsweat Cl− concentrations (22.9 ± 10.5 vs 33.2 ± 15.8 mmol·L−1; P = 0.01) than men. A 20 % of individuals presented asweat Na+ concentration higher than 60 mmol·L−1 while this threshold was not surpassed by any female marathoner. Sweat electrolyte concentration did not correlate to sweat rate, age, body characteristics, experience or training. Although there was a significant correlation between sweat Na+ concentration and running pace (r = 0.18; P = 0.03), this association was weak to interpret that sweat Na+ concentration increased with running pace. Conclusions: The inter-individual variability in sweat electrolyte concentration was not explained by any individual characteristics except for individual running pace and sex. An important portion (20 %) of marathoners might need special sodium intake recommendations due to their high sweat salt losses.

P-Synephrine is a protoalkaloid widely used as an ergogenic aid in sports. This substance has been included in the World Anti-Doping Agency monitoring program, although scientific information about its effects on performance and athletes’ well-being is scarce. The purpose of this investigation was to determine the effectiveness of p-synephrine to increase performance in sprint athletes. In a randomized and counterbalanced order, 13 experienced sprinters performed 2 acute experimental trials after the ingestion of p-synephrine (3 mg·kg−1) or after the ingestion of a placebo (control trial). Forty-five minutes after the ingestion of the substances, the sprinters performed a squat jump, a countermovement jump, a 15-s repeated jump test, and subsequently performed 60-m and 100-m simulated sprint competitions. Self-reported questionnaires were used to assess side-effect prevalence. In comparison with the control trial, the ingestion of p-synephrine did not change countermovement jump height (37.4 ± 4.2 vs 36.7 ± 3.3 cm, respectively; P = 0.52), squat jump height (34.4 ± 3.6 vs 33.9 ± 3.7 cm; P = 0.34), or average 15-s repeated jumps height (31.8 ± 4.1 vs 32.2 ± 3.6 cm; P = 0.18). P-Synephrine did not modify maximal running speed during the 60-m (9.0 ± 0.5 vs 9.0 ± 0.4 m·s−1, respectively; P = 0.55) and 100-m sprint competitions (8.8 ± 0.5 vs 8.8 ± 0.5 m·s−1, respectively; P = 0.92). The ingestion of p-synephrine did not alter the prevalence of headache, gastrointestinal discomforts, muscle pain, or insomnia during the hours following the tests. Acute consumption of 3 mg·kg−1 of p-synephrine was ineffective to increase performance in competitive sprint athletes. Moreover, p-synephrine did not increase the occurrence of side effects after the competition.