551 research outputs found

    Нанохайку и нанохайга, или как нанотехнологиите се срещат с изкуството

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    The present work combines science and arts in an innovative and intriguing way. Using Electron Beam Lithography (EBL) and Directed Self-Assembly (DSA) of Block Co-Polymers (BCP) in conjunction with the shortest poetic form, haiku, the paper attractively demonstrate the capabilities of these nanofabrication techniques and explores the interaction between the top-down EBL process and the bottom-up DSA approach. Silicon (Si) substrates and EBL with the hydrogen silsesquioxane (HSQ) negative tone resist were used for capturing examples of the tiniest haiku poems written and translated into six languages having four different character styles. Subsequently, the haiku nanostructures (“nanohaiku”) were used as guiding features between which the poly(styrene)-blockpoly(ethylene oxide) (PS-b-PEO) diblock copolymer is spin coated to create self-organised nanopatterns. The annealing was done in toluene solvent vapours at 50°C for 1.5 hours and then the samples were immersed in ethanol for 15 hours at 40°C to dissolve the PEO copolymer. In areas within and in-between the individual characters and syllables of the poems, unusual patterns were observed. We interpret them as self-assembled “nanohaiga” directed by the morphology and the linguistic geometry of the nanohaiku. Moreover, we demonstrate how the BCP pattern changes when interacting with the same verse translated into different languages. Thus we add to the haiku poem's own nanostructure and meaning a new visual identity, nanohaiga, combining for the first time poetry, visual art and advanced nanofabrication technologies

    High-temperature oxidation of nickel-based alloys and estimation of the adhesion strength of resulting oxide layers

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    The kinetics of isothermal oxidation (1100°C) of commercial nickel-based alloys with different content of sulfur (0.22–3.2 wt ppm) is studied. The adhesion strength in a metal/oxide system is estimated as a function of sulfur content and duration of high-temperature exposure. The scratch-test technique is proposed to quantitatively estimate the work of adhesion of resulting oxide films. It is found that the film microstructure is composed of an inner α-Al2O3 layer and an outer NiAl2O4 spinel layer, which are separated by discrete inclusions of TiO2. Residual stresses in the oxide film are experimentally determined by X-ray diffraction. spinel layer, which are separated by discrete inclusions of TiO2. Residual stresses in the oxide film are experimentally determined by X-ray diffractio

    Magnetic phase transition in the itinerant helimagnet MnSi: Thermodynamic and transport properties

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    A careful study of thermodynamic and transport properties of a high-quality single crystal of MnSi at ambient pressure suggests that its transition to a helical magnetic state near 29 K is weakly first order. The heat capacity, temperature derivative of resistivity, thermal expansion, and magnetic susceptibility exhibit a specific structure around the phase transition point, interpreted as a combination of first- and second-order features. Striking mirror symmetry between the temperature derivative of resistivity and the thermal expansion coefficient is observed. Conclusions drawn from these experiments question prevailing views on the phase diagram of MnSi

    Infant colic: where is the line between norm and pathology, the role of disruption of the intestinal microbiome

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    Infant colic is one of the most common functional disorders of the gastrointestinal tract in children of the first year of life, worsening the condition of both the child himself and the psychological climate in the family. Infant intestinal colic is a multifactorial symptom complex that requires differential diagnosis between norm and pathology. Until now, there is no clear understanding of the criteria for the need for dietary and drug correction of this condition. The article presents an analysis of the modern literature on the problem of intestinal colic in infants The pathogenesis of functional intestinal colic is determined by a combination of reasons, including the immaturity of the central nervous system, hypothalamic-pituitary system, regulation of the intestinal innervation and the enzymatic system, a certain dependence on psychosocial factors has also been identified, the intestinal microflora has a great influence. H. Kianifar et al. (2014) in the findings of a study noted that a multiprobiotic (seven strains of probiotics and fructooligosaccharides) significantly improved colic symptoms, in particular a reduction in crying time, (82.6%) compared with placebo (35.7%) on day 7 of intake (p < 0.005). On day 30, treatment success was 87% and 46% in the synbiotics and placebo groups, respectively (p < 0.01). The results of a domestic study by I.N. Zakharova et al. (2016) multiprobiotic, which showed that after the use of a multistrain probiotic, intestinal colic remained in 3 (10%) children of the main group and in all children in the placebo group. After taking the probiotic, 80% of children showed normalization of stool, and in the placebo group, stool disorders (loose, watery stools or no stool with the need to empty after an enema) were recorded in 87% of children. Cases from clinical practice with experience of using a multistrain probiotic for colic are shown

    Problematic mobile phone use and smartphone addiction across generations: the roles of psychopathological symptoms and smartphone use

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    Contemporary technological advances have led to a significant increase in using mobile technologies. Recent research has pointed to potential problems as a consequence of mobile overuse, including addiction, financial problems, dangerous use (i.e. whilst driving) and prohibited use (i.e. use in forbidden areas). The aim of this study is to extend previous findings regarding the predictive power of psychopathological symptoms (depression, anxiety and stress), mobile phone use (i.e. calls, SMS, time spent on the phone, as well as the engagement in specific smartphone activities) across Generations X and Y on problematic mobile phone use in a sample of 273 adults. Findings revealed prohibited use and dependence were predicted by calls/day, time on the phone and using social media. Only for dependent mobile phone use (rather than prohibited), stress appeared as significant. Using social media and anxiety significantly predicted belonging to Generation Y, with calls per day predicted belonging to Generation X. This finding suggests Generation Y are more likely to use asynchronous social media-based communication, whereas Generation X engage more in synchronous communication. The findings have implications for prevention and awareness-raising efforts of possibly problematic mobile phone use for educators, parents and individuals, particularly including dependence and prohibited use

    What explains rare and conspicuous colours in a snail? A test of time-series data against models of drift, migration or selection

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    It is intriguing that conspicuous colour morphs of a prey species may be maintained at low frequencies alongside cryptic morphs. Negative frequency-dependent selection by predators using search images ('apostatic selection') is often suggested without rejecting alternative explanations. Using a maximum likelihood approach we fitted predictions from models of genetic drift, migration, constant selection, heterozygote advantage or negative frequency-dependent selection to time-series data of colour frequencies in isolated populations of a marine snail (Littorina saxatilis), re-established with perturbed colour morph frequencies and followed for >20 generations. Snails of conspicuous colours (white, red, banded) are naturally rare in the study area (usually <10%) but frequencies were manipulated to levels of ~50% (one colour per population) in 8 populations at the start of the experiment in 1992. In 2013, frequencies had declined to ~15-45%. Drift alone could not explain these changes. Migration could not be rejected in any population, but required rates much higher than those recorded. Directional selection was rejected in three populations in favour of balancing selection. Heterozygote advantage and negative frequency-dependent selection could not be distinguished statistically, although overall the results favoured the latter. Populations varied idiosyncratically as mild or variable colour selection (3-11%) interacted with demographic stochasticity, and the overall conclusion was that multiple mechanisms may contribute to maintaining the polymorphisms.Heredity advance online publication, 21 September 2016; doi:10.1038/hdy.2016.77

    Prospects for Creation of Cardioprotective and Antiarrhythmic Drugs Based on Opioid Receptor Agonists

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    It has now been demonstrated that the μ, δ(1), δ(2), and κ(1) opioid receptor (OR) agonists represent the most promising group of opioids for the creation of drugs enhancing cardiac tolerance to the detrimental effects of ischemia/reperfusion (I/R). Opioids are able to prevent necrosis and apoptosis of cardiomyocytes during I/R and improve cardiac contractility in the reperfusion period. The OR agonists exert an infarct‐reducing effect with prophylactic administration and prevent reperfusion‐induced cardiomyocyte death when ischemic injury of heart has already occurred; that is, opioids can mimic preconditioning and postconditioning phenomena. Furthermore, opioids are also effective in preventing ischemia‐induced arrhythmias

    Phylogeographic history of flat periwinkles, Littorina fabalis and L. obtusata

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    Background The flat periwinkles, Littorina fabalis and L. obtusata, are two sister species widely distributed throughout the Northern Atlantic shores with high potential to inform us about the process of ecological speciation in the intertidal. However, whether gene flow has occurred during their divergence is still a matter of debate. A comprehensive assessment of the genetic diversity of these species is also lacking and their main glacial refugia and dispersal barriers remain largely unknown. In order to fill these gaps, we sequenced two mitochondrial genes and two nuclear fragments to perform a phylogeographic analysis of flat periwinkles across their distribution range. Results We identified two main clades largely composed by species-specific haplotypes corresponding to L. obtusata and L. fabalis, with moderate to strong support, respectively. Importantly, a model of divergence with gene flow between the two species (from L. obtusata to L. fabalis) was better supported, both in Iberia and in northern-central Europe. Three mitochondrial clades were detected within L. fabalis and two within L. obtusata, with strong divergence between Iberia and the remaining populations. The largest component of the genetic variance within each species was explained by differences between geographic regions associated with these clades. Our data suggests that overall intraspecific genetic diversity is similar between the two flat periwinkle species and that populations from Iberia tend to be less diverse than populations from northern-central Europe. Conclusions The phylogeographic analysis of this sister-species pair supports divergence with gene flow. This system thus provides us with the opportunity to study the contribution of gene flow and natural selection during diversification. The distribution of the different clades suggests the existence of glacial refugia in Iberia and northern-central Europe for both species, with a main phylogeographic break between these regions. Although the genetic diversity results are not fully conclusive, the lower diversity observed in Iberia could reflect marginal conditions at the southern limit of their distribution range during the current interglacial period
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