199 research outputs found
Strong correlation between the antifungal effect of amphotericin B and its inhibitory action on germ-tube formation in a Candida albicans URA+ strain
The hypothetical capacity of amphotericin B to suppress the formation of germ-tubes, which is the first step of yeast-to-hypha conversion in Candida albicans, has been investigated in the wild-type strain CEY.1 (CAI.4-URA+). Exponential cells exposed to concentrations of amphotericin B below or around the MIC90, exhibited a weak reduction in the percentage of human serum-induced germ-tube formation at 37ºC compared with a non-exposed control. However, the dimorphic transition was drastically suppressed after addition of potentially lethal doses of amphotericin B, which also caused severe cell killing. In contrast, an identical experimental approach carried out with the fungistatic compound 5-fluorocytosine had no significant effect on the level of the germ-tube formation. Together, these results strongly point to a close correlation between the fungicidal action of amphotericin B and its ability to impair morphogenetic conversion in C. albicans. [Int Microbiol 2015; 18(1):25-31]Keywords: Candida albicans · amphotericin B · 5-fluorocytosine · germ-tube · cell killin
Trehalose accumulation induced during the oxidative stress response is independent of TPS1 mRNA levels in Candida albicans
Growing cells of the Candida albicans trehalose- deficient mutant tps1/tps1 were extremely sensitive to severe oxidative stress exposure (H2O2). However, their viability was not affected after saline stress or heatshock treatments, being roughly equivalent to that of the parental strain. In wild-type cells, these adverse conditions induced the intracellular accumulation of trehalose together with activation of trehalose-6P synthase, whereas the endogenous trehalose content and the corresponding biosynthetic activity were barely detectable in the tps1/tps1 mutant. The addition of cycloheximide did not prevent the marked induction of trehalose-6P synthase activity. Furthermore, the presence of H2O2 decreased the level of TPS1 mRNA expression. Hence, the conspicuous trehalose accumulation in response to oxidative stress is not induced by increased transcription of TPS1. Our results are consistent with a specific requirement of trehalose in order to withstand a severe oxidative stress in C. albicans, and suggest that trehalose accumulation observed under these conditions is a complex process that most probably involves post-translational modifications of the trehalose synthase complex
Metal mobility assessment in semiarid mine tailings amended with biochar and urban compost: results of a bioassay employing a pioneer plant species
[SPA] El fitomanejo permite reducir el riesgo ambiental de balsas mineras abandonadas. El objetivo del trabajo fue evaluar la movilidad de metales en balsas mineras enmendadas con biochar y/o compost urbano y la efectividad de las enmiendas reduciendo la toxicidad de la solución edáfica para una planta pionera (Zygophyllum fabago). Se llevó a cabo un experimento en mesocosmos (20 meses) con residuo minero con y sin enmienda. Los mesocosmos se mantuvieron a capacidad de campo con agua de la red y se drenaron en diferentes momentos. Se monitorizó la solución edáfica regularmente (pH, conductividad eléctrica, carbono orgánico soluble –COS--, nitrógeno total soluble –NTS- y metales -Mn, Zn-), al igual que el drenaje. Se realizó un bioensayo con semillas de Z. fabago con la solución edáfica de mitad del experimento (germinación de semillas, crecimiento de plántulas). Los tratamientos con compost urbano mostraron mayor concentración inicial de COS y metales en solución. Se observó un descenso temporal de la concentración de DOC y metales en la solución edáfica debido a su lixiviación en el drenaje. A pesar del mayor contenido de metales, el compost urbano favoreció la elongación de la raíz debido al mayor contenido de COS y NTS en solución.
[ENG] Phytomanagement allows to reduce the environmental risks of abandoned mine tailings. The aim of this work was to assess metal mobility in mine tailings amended with biochar and/or urban compost and the effectiveness of these amendments for reducing the toxicity of soil solution to a pioneer plant species (Zygophyllum fabago). A mesocosm experiment was performed (20 months) with mine wastes with and without amendment. Mesocosms were maintained at field capacity with tap water and drained at different times. Soil solution was regularly monitored (pH, electrical conductivity, dissolved organic carbon –DOC-, dissolved total nitrogen –TDN- and metals -Mn, Zn-), as well as drainage. A bioassay with seeds of Z. fabago was performed with midterm soil solution (seed germination, seedling performance). Treatments containing urban compost showed higher initial DOC and metal concentrations in solution. A decrease of DOC and metal concentrations in soil solution with time occurred due to their lixiviation in the drainage water. In spite of the higher metal pool, urban compost favoured root length due to its greater content of DOC and TDN in soil solution.Financial support for this research was provided by the Ministerio de Economía y Competitividad of Spain and FEDER (Project CTM2014-54029-R) and Fundación Séneca de CARM (19248/PI/14). Obdulia Martínez holds a FPI contract from the Ministerio de Economía y Competitividad of Spain (BES-2015-075838). Dr. González-Alcaraz holds a Marie Skłodowska-Curie contract (H2020-MSCA-IF-2015, Project ID 704332)
Changes in rearfoot strike patterns over childhood: A 3-year prospective longitudinal cohort study.
Rearfoot strike (RFS) in children running produces impact forces that give rise to a transient stress wave traveling through the body. It could contribute to the development of injuries. The purpose of this study was to determine RFS prevalence during childhood while running at a self-selected velocity in a prospective longitudinal cohort study. A total of 175 children (68 girls), aged 6 to 14 years, participated in this study. The sample was divided into three age groups (age in 2016): 6-8 years, 9-11 years, and 12-14 years, which were analysed again three years later (2019). A 2D video-based analysis was used to record the RFS. Taking into account all samples, in the jogging trial the prevalence of RFS (an average of both feet) was 86.9% in 2016 and 94.7% three years later; in the running trial the prevalence was 82.6 and 94.4%, respectively. In all samples a significant increase of RFS prevalence was found in both the jogging and running trials for both feet over three years (jogging, left foot, p=.011, right foot, p=.023; running, left foot, p=.001, right foot, p<.001). In girls, there were no significant differences in any conditions. In boys, a significant increase of RFS prevalence was found after three years in both feet (p<.01) in the running trial. This study shows that RFS prevalence in children increases with age and the results may be used to characterize typical running development in children population
Testing alternative theoretical accounts of code-switching: Insights from comparative judgments of adjective–noun order
Objectives:Spanish and English contrast in adjective–noun word order: for example, brown dress (English) vs. vestido marrón (‘dress brown’, Spanish). According to the Matrix Language model ( MLF) word order in code-switched sentences must be compatible with the word order of the matrix language, but working within the minimalist program (MP), Cantone and MacSwan arrived at the descriptive generalization that the position of the noun phrase relative to the adjective is determined by the adjective’s language. Our aim is to evaluate the predictions derived from these two models regarding adjective–noun order in Spanish–English code-switched sentences.Methodology:We contrasted the predictions from both models regarding the acceptability of code-switched sentences with different adjective–noun orders that were compatible with the MP, the MLF, both, or none. Acceptability was assessed in Experiment 1 with a 5-point Likert and in Experiment 2 with a 2-Alternative Forced Choice (2AFC) task.Data and analysis:Data from both experiments were subjected to linear mixed model analyses. Results from the 2AFC task were also analyzed using Thurstone’s law of comparative judgment.Conclusions:We found an additive effect in which both the language of the verb and the language of the adjective determine word order.Originality:Both experiments examine adjective–noun word order in English–Spanish code-switched sentences. Experiment 2 represents a novel application of Thurstone’s law of comparative judgements to the study of linguistic acceptability which yielded clearer results than Likert scales. We found convincing evidence that neither the MLF nor the MP can fully account for the acceptability of adjective–noun switches.Implications:We suggest that advances in our understanding of grammaticality in code-switching will be achieved by combining the insights of the two frameworks instead of considering them in isolation, or by espousing a probabilistic model of code-switching.Theoretical and Experimental Linguistic
Pacing profiles, variability and progression in 400, 800 and 1500-m freestyle swimming events at the 2021 European Championship
Performance intra-variability has not been studied in long-distance swimming. The aims were to describe the pacing profile in 400-, 800- and 1500-m freestyle events and to analyse the variability (coefficient of variation[CV]) and performance progression (%Δ) within and between rounds. A total of 256 swims of 130 eliteswimmers (70 males and 60 females) were analysed at the 2021 European Championship (indoor long-course). Linear mixed-effect models were applied for each swimmer and race time performances to obtain the CV and %Δ between each lap and rounds (i.e. heats and final). T-test was conducted to compare the CV between medallist and non-medallist. First and last laps were the fastest (p < 0.001) in all events compared to the intermediate laps which showed an evenly-pace. Parabolic pacing profile was adopted in all events. Male swimmers obtained a CV-average of 0.52 ± 0.49% between rounds (−0.64 ± 0.8%Δ) and females, a CVaverage of 0.70 ± 0.45 (−0.71 ± 0.92%Δ). Medallist swimmers obtained higher CV between rounds (1.00–1.08%) compared to non-medallist finalist (0.22–0.47%). Parabolic pacing profiles were adopted in 400-, 800-, and 1500-m races. The best swimmers adopt conservative strategies in heats to improve their performance in final, obtaining higher CV and %Δ between rounds.This study was supported by grants awarded by the Ministry of Science, Innovation and Universities (Spanish Agency of Research) and the European Regional Development Fund (ERDF); PGC2018–102116–B–I00 ‘SWIM II: Specific Water Innovative Measurements: Applied to the performance improvement’ and the Spanish Ministry of Education, Culture and Sport: FPU19/02477, FPU 16/02629, and FPU17/02761 grants
Culturas digitales: ¿en qué contexto producimos?
Internet constituye hoy un espacio en el cual habitamos durante largas horas de nuestras vidas. Nos cuesta imaginarnos por fuera de la Red, se nos dificulta pensar nuestros trabajos, nuestros modos de vincularnos, nuestros consumos culturales, entre otras cosas. Internet no solo aparece en nuestras vidas en los momentos de ocio, sino que también es fundamental para nuestra productividad cotidiana. Entonces, resulta indispensable comprender de qué se trata. Natalia Zuazo (2015) dice que no es casual que nos hayamos hecho la imagen de Internet como una “nube”, como una representación sin cables, intangible, blanca y luminosa. Muy por el contrario, “Internet es ese mundo lleno de tubos, cables, tierra, agua, arena y centros de datos aburridos con luces que se quedan solas de noche titilando sin fiestas ni plazas soleadas alrededor” (p. 15). Comprender la materialidad de Internet nos ayuda a visualizar a la Red como un espacio que también está atravesado por las lógicas del poder, con dueños, precios y disputas en el mercado. En ese sentido, debemos “pensar las tecnologías en su espesor cultural, político y social” (Racioppe, 2012, p. 112) y no detenernos en realizar una mirada meramente instrumental de las mismas. De ese modo, nuestro análisis partirá de comprender a las tecnologías como instituciones sociales ya que, como plantea Raymond Williams (1992), no se puede pensar a los inventos técnicos por fuera de las sociedades.Facultad de Periodismo y Comunicación Socia
Load that maximizes power output in countermovement jump
Introduction:
One of the main problems faced by strength and conditioning coaches is the issue of how to objectively quantify and monitor the actual training load undertaken by athletes in order to maximize performance. It is well known that performance of explosive sports activities is largely determined by mechanical power.
Objective:
This study analysed the height at which maximal power output is generated and the corresponding load with which is achieved in a group of male-trained track and field athletes in the test of countermovement jump (CMJ) with extra loads (CMJEL).
Methods:
Fifty national level male athletes in sprinting and jumping performed a CMJ test with increasing loads up to a height of 16 cm. The relative load that maximized the mechanical power output (Pmax) was determined using a force platform and lineal encoder synchronization and estimating the power by peak power, average power and flight time in CMJ.
Results:
The load at which the power output no longer existed was at a height of 19.9 ± 2.35, referring to a 99.1 ± 1% of the maximum power output. The load that maximizes power output in all cases has been the load with which an athlete jump a height of approximately 20 cm.
Conclusion:
These results highlight the importance of considering the height achieved in CMJ with extra load instead of power because maximum power is always attained with the same height. We advise for the preferential use of the height achieved in CMJEL test, since it seems to be a valid indicative of an individual's actual neuromuscular potential providing a valid information for coaches and trainers when assessing the performance status of our athletes and to quantify and monitor training loads, measuring only the height of the jump in the exercise of CMJEL.Actividad Física y Deport
Guía de requisitos de arquitectura bioclimática para el cantón Portoviejo
The research tries to make a conceptual analysis of the bioclimatic architecture, preserving its importance for achieving a sustainable society through the appropriate use of indigenous resources, where high comfort and high constructive aesthetics is ensured. It briefly explains the concept of housing and synthetically analyzes the housing problem and the solutions adopted by man since the emergence of the human species until now. Cultural penetration of the major industrialized powers in constructive art of Latin American countries analyzed, where the overwhelming passage of modernity and penetration of technological development, threatens to erase any vestige of constructive cultural tradition, creating more dependency and inequality at the level of the society. The role of architecture as social work and responsibility to be assumed to environmental protection of the planet, seeking consideration of the environmental conditions, and exploitation at all costs the natural resources available in terms of environmental sustainability stands. It is offered as a result of the study, a group of technical recommendations set out so early, focused on ensuring the bioclimatic design of homes in the Canton Portoviejo.
Index Terms— green architecture, local resources, renewable energy, hygrothermal comfort
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