1,723 research outputs found

    Contributions of each of the four swimming strokes to elite 200-400 individual medley swimming performance in short and long course competitions

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    OBJECTIVES: The relative contribution of each of the four strokes to performance, and whether these contributions differ substantially between short course and long course competitions is unclear. To clarify these issues the aim of this study was to assess the strokes that have more influence on the performance in the 200 and 400 m IM swimming performances of elite male and female swimmers, participating in major events: Olympic Games (OG) and World Championship (WC) in short-course and long-course from 2012 to 2021.METHODS: Data from 1,095 swimmers (501 women and 594 men) who competed in 200 and 400-m IM were obtained with a minimum level of 800 FINA points. Linear regression modelling and classification trees were employed to quantify differences between strokes and short/long course swimming.RESULTS: Regression analysis indicated that breaststroke ( β = - 0.191; p &lt; 0.000) and backstroke ( β = - 0.185; p &lt; 0.000) had a bigger effect on IM performance, with butterfly ( β = - 0.101; p &lt; 0.000) having a lesser impact. The classification trees showed threshold performance standards in terms of 50-m times in form-stroke events must be fulfilled to attain medal-winning performances. CONCLUSIONS: These form-stroke standards represent important milestones for designing medal-oriented training strategies for both 200 IM and 400 m IM. Achieving a medallist position in 200 and 400 m IM requires obtaining specified lap times in butterfly, breaststroke and backstroke for males and females in long-course competitions, and breaststroke and backstroke for short-course competitions. The OG presents more exigent demands of lap times in butterfly, crawl and backstroke for IM swimmers.</p

    A metabolite profile reveals the presence of neurodegenerative conditions according to severity of hydrocephalus

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    Introduction: In obstructive congenital hydrocephalus, cerebrospinal fluid accumulation is associated with high intracranial pressure (ICP), ischemia/hypoxia, metabolic impairment, neuronal damage and astrocytic reaction. The hyh mutant mice exhibit two different forms of hydrocephalus evolution: severe and moderate. A study was carried out in hyh mice to detect a metabolite profile that define the tissue response in each hydrocephalus form. Methods: Metabolites levels in brain cortex were analyzed with 1H High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (1H HR-MAS) spectroscopy. The study was complemented with ICP recording and histopathological analysis. Results: Mice with severe hydrocephalus were found to have higher ICP and stronger astrocytic reaction. Several metabolites including glutamate and glutamine were found to correlate with the severity of hydrocephalus. The whole metabolite profile may be explained based in differential astrocyte reactions, neurodegenerative and ischemic conditions. The glutamate transporter EAAT2 and the metabolite taurine were found as key histopathological markers for the damaged parenchyma. Conclusions: Spectroscopy allowed the detection of a metabolite profile related to intracranial pressure and hydrocephalus severity, and therefore can be useful to monitor the efficacy of experimental therapies. Supported by Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech, and PI15/0619 (ISCIII/FEDER).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Supported by Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech, and PI15/0619 (ISCIII/FEDER)

    Long-time effects of an experimental therapy with mesenchymal stem cells in congenital hydrocephalus

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    Introduction: Bone marrow-derived mesenchymal stem cells (BM-MSC) are a potential therapeutic tool due to their ability for migrating and producing neuroprotector factors when they are transplanted in other neurodegenerative diseases. Moreover, some investigations have shown that BM-MSC are able to modulate astrocyte activation and neuroprotector factor production. The aim of this study was to evaluate the long-time effects of a BM-MSC experimental therapy in the hyh mouse model of congenital hydrocephalus. Methods: BM-MSC were characterized in vitro and then transplanted into the ventricles of young hydrocephalic hyh mice, before they develop the severe hydrocephalus. Non-hydrocephalic normal mice (wt) and hydrocephalic hyh mice sham-injected (sterile saline serum) were used as controls. Samples were studied by analyzing and comparing mRNA, protein level expressions and immunoreaction related with the progression and severity of hydrocephalus. Results: Fourteen days after transplantation, hydrocephalic hyh mice with BM-MSC showed lower ventriculomegaly. In these animals, BM-MSC were found undifferentiated and spread into the periventricular astrocyte reaction. There, BM-MSC were detected producing several neuroprotector factors (BDNF, GDNF, NGF, VEGF), in the same way as reactive astrocytes. Total neocortical levels of NGF, TGF-β and VEGF were found increased in hydrocephalic hyh mice transplanted with BM-MSC. Furthermore, astrocytes showed increased expressions of aquaporin-4 (water channel protein) and Slit-2 (neuroprotective and anti-inflammatory molecule). Conclusions: BM-MSC seem to lead to recovery of the severe neurodegenerative conditions associated to congenital hydrocephalus mediated by reactive astrocytes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. PI15/0619 (ISCIII/FEDER

    Continuous Positive Airway Pressure Treatment in Patients with Alzheimer's Disease: A Systematic Review

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    Background: Epidemiological studies have suggested a pathophysiological relationship between obstructive sleep apnea syndrome (OSAS) and Alzheimer's disease (AD). The aim of this study is to evaluate the treatment of obstructive sleep apnea with continuous positive airway pressure (CPAP) in AD and its relationship with neurocognitive function improvement. Methods: Systematic review conducted following PRISMA's statements. Relevant studies were searched in MEDLINE, PEDro, SCOPUS, PsycINFO, Web of Science, CINAHL and SportDicus. Original studies in which CPAP treatment was developel in AD patients have been included. Results: 5 studies, 3 RCTs (Randomized controlled trials) and 2 pilot studies. In all RCTs the CPAP intervention was six weeks; 3 weeks of therapeutic CPAP vs. 3 weeks placebo CPAP (pCPAP) followed by 3 weeks tCPAP in patients with AD and OSA. The two pilot studies conducted a follow-up in which the impact on cognitive impairment was measured. Conclusions: CPAP treatment in AD patients decreases excessive daytime sleepiness and improves sleep quality. There are indications that cognitive deterioration function measured with the Mini Mental Scale decreases or evolves to a lesser extent in Alzheimer's patients treated with CPAP. Caregivers observe stabilization in disease progression with integration of CPAP. More research is needed on the topic presented

    Non-enzymatic glucose sensor using mesoporous carbon screen-printed electrodes modified with cobalt phthalocyanine by phase inversion

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    The development of non-enzymatic glucose electrochemical sensors is still required to be used for the determination of glucose in complex biological media. This study presents a straightforward and remarkably efficient tool for the preparation of highly stable and sensitive glucose electrochemical sensors based on the deposition of cobalt phthalocyanine (CoPc) onto mesoporous carbon screen-printed electrodes (MCs). Results show that the MC electrochemical activation (aMC) followed by phase inversion (PI), which consisted of drop casting of CoPc in dimethylformamide onto a wetting electrolyte leading to the electrode aMC-CoPc/PI, enhanced sensitivity towards glucose determination in complex media. The beneficial need for MC surface activation and PI has been explored by scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The aMC-CoPc/PI electrode exhibited the highest electrocatalytic activity of the series (namely, MC-CoPc, MC-CoPc/PI and aMC-CoPc) towards glucose oxidation. By using square wave voltammetry technique, the aMC-CoPc/PI glucose electrochemical sensor demonstrated a sensitivity of 22.3 µA mM−1 and a low detection limit of 27.4 µM (S/N = 3) in a linear dynamic range of 0.1 to 3.5 mM. Additionally, it also displayed high selectivity, robust stability, repeatability and reproducibility toward the quantification of glucose concentration in complex samples such as horse serum, intravenous glucose saline solution and culture medium for sperm cells.This work was partially supported by the research project TED2021-129921B-C21 funded by MCIN/AEI/https://doi.org/10.13039/501100011033 and by the European Union NextGeneration EU/PRTR, and grant No. 2022-GRIN-34199 funded by the own research plan of the UCLM for applied research projects, co-financed by the European Fund for Regional Development (FEDER). The authors also want to acknowledge Ministerio de Ciencia, Innovación y Universidades (Spain) for the support through ELECTROBIONET (RED2022-134120-T) from MCIN/AEI/https://doi.org/10.13039/501100011033. MIGS is a postdoctoral researcher of the own research plan of the UCLM funded from the EU through the European Social Fund Plus (ESF+) (Ref. PI001523). RJP is the beneficiary of a postdoctoral contract associated with the indicated project from the MCIN/AEI. HK received a grant from Laboratoire of Physics of Materials: structure and properties (LR01ES15), University of Carthage (Tunisia), to perform a scientific internship at the UCLM

    Highly activated screen-printed carbon electrodes by electrochemical treatment with hydrogen peroxide

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    An easy effective method for the activation of commercial screen-printed carbon electrodes (SPCEs) using H2O2 is presented to enhance sensing performances of carbon ink. Electrochemical activation consists of 25 repetitive voltammetric cycles at 10 mV s−1 using 10 mM H2O2 in phosphate buffer (pH 7). This treatment allowed us to reach a sensitivity of 0.24 ± 0.01 μA μM−1 cm−2 for the electroanalysis of H2O2, which is 140-fold higher than that of untreated SPCEs and 6-fold more than screen-printed platinum electrodes (SPPtEs). Electrode surface properties were characterized by SEM, EIS and XPS. The results revealed atomic level changes at the electrode surface, with the introduction of new carbon‑oxygen groups being responsible for improved electro-transfer properties and sensitivity. Our method was compared with other previously described ones. The methodology is promising for the activation of commercial carbon inks-based electrodes for sensor applications.This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO, http://www.mineco.gob.es/portal/site/mineco/idi), Projects No. BFU2016-75609-P (cofunded with FEDER funds, EU) and CTQ2016-76231-C2-2-R. BGM is a post-doctoral research fellow of the Youth Employment Initiative (JCCM, Spain, cofounded with ESF funds, EU)

    Electrochemical performance of activated screen printed carbon electrodes for hydrogen peroxide and phenol derivatives sensing

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    Screen-printed carbon electrodes (SPCEs) are widely used for the electroanalysis of a plethora of organic and inorganic compounds. These devices offer unique properties to address electroanalytical chemistry challenges and can successfully compete in numerous aspects with conventional carbon-based electrodes. However, heterogeneous kinetics on SPCEs surfaces is comparatively sluggish, which is why the electrochemical activation of inks is sometimes required to improve electron transfer rates and to enhance sensing performance. In this work, SPCEs were subjected to different electrochemical activation methods and the response to H2O2 electroanalysis was used as a testing probe. Changes in topology, surface chemistry and electrochemical behavior to H2O2 oxidation were performed by SEM, XPS, cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The combination of electrochemical activation methods using H2SO4 and H2O2 proved particularly effective. A reduction in charge transfer resistance, together with functionalization with some carbon‑oxygen groups on carbon ink surfaces, were likely responsible for such electrochemical improvement. The use of a two-step protocol with 0.5 M H2SO4 and 10 mM H2O2 under potential cycling conditions was the most effective activation procedure investigated herein, and gave rise to 518-fold higher sensitivity than that obtained for the untreated SPCEs upon H2O2 electrooxidation. The electrochemical behavior of acetaminophen, hydroquinone and dopamine is also shown, as a proof of concept upon the optimum activated SPCEs.This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO, http://www.mineco.gob.es/portal/site/mineco/idi), Projects No. BFU2016-75609-P (AEI/FEDER, UE) and CTQ2016-76231-C2-2-R, and by the Junta de Comunidades de Castilla-La Mancha (Spain), Project No. SBPLY/17/180501/000276/2 (cofunded with FEDER funds, EU). BGM is a post-doctoral research fellow of the Youth Employment Initiative (JCCM, Spain, cofunded with ESF funds, EU)

    Learning To Be Teachers In Transforming Schools

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    El trabajo que se presenta refleja parte de la investigación que se lleva a cabo en la Facultad de Ciencias de la Educación sobre voluntariado, aprendizaje y comunidades de aprendizaje y como parte del Proyecto de I+D+I: Ecologías del desarrollo y aprendizaje expandido.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Glucose Biosensor Based on Disposable Activated Carbon Electrodes Modified with Platinum Nanoparticles Electrodeposited on Poly(Azure A)

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    Herein, a novel electrochemical glucose biosensor based on glucose oxidase (GOx) immobilized on a surface containing platinum nanoparticles (PtNPs) electrodeposited on poly(Azure A) (PAA) previously electropolymerized on activated screen-printed carbon electrodes (GOx-PtNPs-PAA-aSPCEs) is reported. The resulting electrochemical biosensor was validated towards glucose oxidation in real samples and further electrochemical measurement associated with the generated H2O2. The electrochemical biosensor showed an excellent sensitivity (42.7 μA mM−1 cm−2), limit of detection (7.6 μM), linear range (20 μM–2.3 mM), and good selectivity towards glucose determination. Furthermore, and most importantly, the detection of glucose was performed at a low potential (0.2 V vs. Ag). The high performance of the electrochemical biosensor was explained through surface exploration using field emission SEM, XPS, and impedance measurements. The electrochemical biosensor was successfully applied to glucose quantification in several real samples (commercial juices and a plant cell culture medium), exhibiting a high accuracy when compared with a classical spectrophotometric method. This electrochemical biosensor can be easily prepared and opens up a good alternative in the development of new sensitive glucose sensors.This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO, http://www.mineco.gob.es/portal/site/mineco/idi), projects Nos. BFU2016-75609-P (AEI/FEDER, UE) and CTQ2016-76231-C2-2-R; the Spanish Ministry of Science, Innovation, and Universities, project No. PID2019-106468RB-I00; and by the Junta de Comunidades de Castilla-La Mancha (Spain), project No. SBPLY/17/180501/000276/2 (cofunded with FEDER funds, EU)

    Stenotrophomonas goyi sp. nov., a novel bacterium associated with the alga Chlamydomonas reinhardtii [version 2; peer review: 2 approved]

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    Background: A culture of the green algae Chlamydomonas reinhardtii was accidentally contaminated with three different bacteria in our laboratory facilities. This contaminated alga culture showed increased algal biohydrogen production. These three bacteria were independently isolated. Methods: The chromosomic DNA of one of the isolated bacteria was extracted and sequenced using PacBio technology. Tentative genome annotation (RAST server) and phylogenetic trees analysis (TYGS server) were conducted. Diverse growth tests were assayed for the bacterium and for the alga-bacterium consortium. Results: Phylogenetic analysis indicates that the bacterium is a novel member of the Stenotrophomonas genus that has been termed in this work as S. goyi sp. nov. A fully sequenced genome (4,487,389 base pairs) and its tentative annotation (4,147 genes) are provided. The genome information suggests that S. goyi sp. nov. is unable to use sulfate and nitrate as sulfur and nitrogen sources, respectively. Growth tests have confirmed the dependence on the sulfur-containing amino acids methionine and cysteine. S. goyi sp. nov. and Chlamydomonas reinhardtii can establish a mutualistic relationship when cocultured together. Conclusions: S. goyi sp. nov. could be of interest for the design of biotechnological approaches based on the use of artificial microalgae-bacteria multispecies consortia that take advantage of the complementary metabolic capacities of their different microorganisms
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