Enhancing cognitive functions through noninvasive brain stimulation is of enormous public interest, particularly for the aging population in whom processes such as working memory are known to ...decline. In a randomized double-blind crossover study, we investigated the acute behavioral and neural aftereffects of bifrontal and frontoparietal transcranial direct current stimulation (tDCS) combined with visual working memory (VWM) training on 25 highly educated older adults. Resting-state functional connectivity (rs-FC) analysis was performed prior to and after each stimulation session with a focus on the frontoparietal control network (FPCN). The bifrontal montage with anode over the left dorsolateral prefrontal cortex enhanced VWM accuracy as compared to the sham stimulation. With the rs-FC within the FPCN, we observed significant stimulation×time interaction using bifrontal tDCS. We found no cognitive aftereffects of the frontoparietal tDCS compared to sham stimulation. Our study shows that a single bifrontal tDCS combined with cognitive training may enhance VWM performance and rs-FC within the relevant brain network even in highly educated older adults.
The authors in this article are discussing about different problematic areasin terms of patriotism, including legal environment, forms and ways ofeducation, as well as about the negative ...manifestations and consequencesof misunderstanding principles in patriotism from the individuals point ofview. The main aim of the article is the assessment of the basic features ofpatriotism via analyses the mentioned areas and spheres of patriotismmainly in the conditions of Slovak Republic. In the publication process theauthors consulted the given facts with a lot of experts, not only fromacademic environment but as well as from the environment of publicauthorities and institutions, for example Matica Slovenská and SlovakUnion of Anti-Fascist Fighters.
The electrical conductivity of molten K3AlF6, Rb3AlF6, Cs3AlF6, and CsF was measured at various temperatures using a pyrolytic boron nitride tube, platinum–rhodium alloy electrode, and alternating ...current impedance method. The electrical conductivity of molten K3AlF6 was found to be 2.64 S·cm–1 at 1273 K. The electrical conductivity of molten Rb3AlF6 was found to be 2.06 S·cm–1 at 1273 K. The conductivity of molten Cs3AlF6 at the same temperature is 1.36 S·cm–1 because the conductivity of CsF at 1273 K was found to be 2.57 S·cm–1. The electrical conductivity values steadily drop from lithium fluoride/fluoroaluminate through sodium and potassium to cesium fluoride/fluoroaluminate. This fall in conductivity is probably because of the increase in the size and mass of the cations (activation energy increases with decreasing conductivity).
Prosodic features are important in achieving intelligibility, comprehensibility, and fluency in a second or foreign language (L2). However, research on the assessment of prosody as part of oral ...proficiency remains scarce. Moreover, the acoustic analysis of L2 prosody has often focused on fluency-related temporal measures, neglecting language-dependent stress features that can be quantified in terms of syllable prominence. Introducing the evaluation of prominence-related measures can be of use in developing both teaching and assessment of L2 speaking skills. In this study we compare temporal measures and syllable prominence estimates as predictors of prosodic proficiency in non-native speakers of English with respect to the speaker’s native language (L1).
The predictive power of temporal and prominence measures was evaluated for utterance-sized samples produced by language learners from four different L1 backgrounds: Czech, Slovak, Polish, and Hungarian. Firstly, the speech samples were assessed using the revised Common European Framework of Reference scale for prosodic features. The assessed speech samples were then analyzed to derive articulation rate and three fluency measures. Syllable-level prominence was estimated by a continuous wavelet transform analysis using combinations of F0, energy, and syllable duration.
The results show that the temporal measures serve as reliable predictors of prosodic proficiency in the L2, with prominence measures providing a small but significant improvement to prosodic proficiency predictions. The predictive power of the individual measures varies both quantitatively and qualitatively depending on the L1 of the speaker. We conclude that the possible effects of the speaker’s L1 on the production of L2 prosody in terms of temporal features as well as syllable prominence deserve more attention in applied research and developing teaching and assessment methods for spoken L2.
The production of the pineal hormone melatonin is synchronized with day-night cycle via multisynaptic pathway including suprachiasmatic nucleus linking several physiological functions to diurnal ...cycle. The recent data indicate that impaired melatonin production is involved in several cardiovascular pathologies including hypertension and ischemic heart disease. However, the mechanisms of melatonin effect on cardiovascular system are still not completely understood. The activation of melatonin receptors on endothelial and vascular smooth muscle cells and antioxidant properties of melatonin could be responsible for the melatonin effects on vascular tone. However, the data from in vitro studies are controversial making the explanation of the melatonin effect on blood pressure in vivo difficult. In vivo, melatonin also attenuates sympathetic tone by direct activation of melatonin receptors, scavenging free radicals or increasing NO availability in the central nervous system. The central and peripheral antiadrenergic action of chronic melatonin treatment might eliminate the mechanisms counter-regulating decreased blood pressure, providing thus additional cardioprotective mechanism. The extraordinary antioxidant activity and antilipidemic effects of melatonin may enhance the modulation of blood pressure by melatonin and probably play the most important role in the amelioration of target organ damage by chronic melatonin treatment. Further investigation of these mechanisms should provide novel knowledge about pathophysiological mechanisms of cardiovascular diseases, additional explanation for their circadian and seasonal variability and potentially generate new impulses for the development of therapeutic arsenal.
Genetic and genomic studies provide valuable insight into the inheritance, structure, organization, and function of genes. The knowledge gained from the analysis of plant genes is beneficial to all ...aspects of plant research, including crop improvement. New methods and tools are continually being developed to facilitate rapid and accurate mapping, sequencing, and analyzing of genes. Here, I review the recent progress in the application of high-resolution melting (HRM) analysis of DNA, a method that allows detecting polymorphism in double-stranded DNA by comparing profiles of melting curves. Use of HRM has expanded considerably in the past few years as the method was successfully applied for high-throughput genotyping, mapping genes, testing food products and seeds, and other areas of plant research.
DNA is subject to mutations that change the information that is contained in the genome.
The detection and study of spontaneous and induced mutations is essential for the understanding of changes in phenotypic variation and evolution of species.
High-resolution DNA melting analysis (HRM) allows for the systematic screening of mutants by the way of analyzing differences in melting curves of amplicons.
This approach does not require previous knowledge of the possible haplotypes, does not need fluorescent labels, and multiple alleles can be detected in a single amplicon.
HRM has recently been applied to identify induced mutations as well as natural variants in numerous plant species.
The method can be used for high-throughput genotyping, mapping genes, testing food products, and in other areas of plant research.
5-hydroxymethyl-2-furaldehyde (HMF) is not only indicator of food freshness and quality, but also contaminant forming during Maillard reaction, or by dehydratation of saccharides, respectively. While ...data about presence of HMF in white and brown sugar are scarce, 13 kinds of white sugar and 25 kinds of brown sugar were analysed. Sugar was dissolved in deionised water, clarified with Carrez solutions, filtered and content of HMF was determined using high performance liquid chromatography with diode array detector (HPLC-DAD) with detection at 284 nm when separation run on Poroshel 120 EC C18 at 32 °C. Elution was performed under isocratic conditions using 95:5 water/acetonitrile mobile phase at a flow rate of 0.9 mL/min and analysis run 5 min. Method was validated in in house regime and its parameters such as limit of detection – (LOD = 0.05 mg/kg), limit of quantification (LOQ = 0.15 mg/kg), specificity, repeatability and recovery enabled its application for sugar analysis. While white sugar was free of HMF, all kinds of brown sugar exhibited presence of HMF, when content in 15 kinds varied between 0.17 and 6.45 mg/kg, content in other 10 kinds was under LOQ. On the base of obtained results was postulated that brown sugar contains HMF either due to absence of refining processes, or it is re-contaminated by treacle adding to white sugar during production of brown sugar.
•HMF content in white and brown sugar available on Slovakian market was analysed.•For these purposes, simply and rapid HPLC method for determination was elaborated and validated in in house regime.•While all 13 kinds of white sugar was free of HMF, all 25 kinds of brown sugar contained HMF.
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