Masaryk University
  • Brno, Czech Republic , Czechia
Recent publications
Although the general concept of nanotechnology relies on exploitation of size-dependent properties of nanoscaled materials, the relation between the size/morphology of nanoparticles with their biological activity remains not well understood. Therefore, we aimed at investigating the biological activity of Se nanoparticles, one of the most promising candidates of nanomaterials for biomedicine, possessing the same crystal structure, but differing in morphology (nanorods vs. spherical particles) and aspect ratios (AR, 11.5 vs. 22.3 vs. 1.0) in human cells and BALB/c mice. Herein, we report that in case of nanorod-shaped Se nanomaterials, AR is a critical factor describing their cytotoxicity and biocompatibility. However, spherical nanoparticles (AR 1.0) do not fit this statement and exhibit markedly higher cytotoxicity than lower-AR Se nanorods. Beside of cytotoxicity, we also show that morphology and size substantially affect the uptake and intracellular fate of Se nanomaterials. In line with in vitro data, in vivo i.v. administration of Se nanomaterials revealed the highest toxicity for higher-AR nanorods followed by spherical nanoparticles and lower-AR nanorods. Moreover, we revealed that Se nanomaterials are able to alter intracellular redox homeostasis, and affect the acidic intracellular vesicles and cytoskeletal architecture in a size- and morphology-dependent manner. Although the tested nanoparticles were produced from the similar sources, their behavior differs markedly, since each type is promising for several various application scenarios, and the presented testing protocol could serve as a concept standardizing the biological relevance of the size and morphology of the various types of nanomaterials and nanoparticles.
Memory-like responses in innate immune cells confer nonspecific protection against secondary exposures. A number of microbial agents have been found to induce enhanced or diminished recall responses in innate cells, however, studies investigating the ability of probiotic bacteria to trigger such effects are lacking. Here, we show that priming of human monocytes with a secretome from the gut probiotic bacterium Limosilactobacillus (L.) reuteri induces a mixed secondary response phenotype in monocyte-derived dendritic cells (mo-DCs), with a strong IL-6 and IL-1β response but low TNFα, IL-23 and IL-27 secretion. Instead, blood DC priming with L. reuteri-secretome resembles a tolerant state upon secondary exposure. A similar pattern was found in conventional and gut-like (retinoic acid exposed) DCs, although retinoic acid hampered TNFα and IL-6 production and enrichment of histone modifications in L. reuteri-secretome primed mo-DC cultures. Further, we show that the memory-like phenotype of mo-DCs, induced by priming stimuli, is important for subsequent T helper (Th) cell differentiation pathways and might determine the inflammatory nature of Th cells. We also show enhanced recall responses characterized by robust inflammatory cytokines and lactate production in the gut-like mo-DCs derived from β-glucan primed monocytes. Such responses were accompanied with enriched histone modifications at the promoter of genes associated with a trained phenotype in myeloid cells. Altogether, we demonstrate that a gut commensal-derived secretome prompts recall responses in human DCs which differ from that induced by classical training agents such as β-glucan. Our results could be beneficial for future therapeutic interventions where T cell responses are needed to be modulated.
Electronic properties of selected quantum dot (QD) systems are surveyed based on the multi-band k·p method, which we benchmark by direct comparison to the empirical tight-binding algorithm, and we also discuss the newly developed “linear combination of quantum dot orbitals” method. Furthermore, we focus on two major complexes: First, the role of antimony incorporation in InGaAs/GaAs submonolayer QDs and In 1− x Ga x As y Sb 1− y /GaP QDs, and second, the theory of QD-based quantum cascade lasers and the related prospect of room temperature lasing.
Background Barley has been bred for more than a century in the Nordic countries, with dramatic improvements of yield traits. In this study we investigate if this has come at the cost of lower grain protein and micronutrient (iron, zinc) content, by analysing 80 accessions representing four different improvement stages. We further re-sequenced the two grain protein content associated genes HvNAM-1 and HvNAM-2 in full and performed expression analyses of the same genes to search for genetic associations with nutrient content. Results We found higher thousand grain weight in barley landraces and in accessions from the late improvement group compared to accessions from the mid of the twentieth century. Straw length was much reduced in late stage accessions. No significant temporal decrease in grain protein, iron or zinc content during twentieth century Nordic crop improvement could be detected. Out of the 80 accessions only two deviant HvNAM-1 sequences were found, represented by one accession each. These do not appear to be correlated to grain protein content. The sequence of HvNAM-2 was invariable in all accessions and no correlations between expression levels of HvNAM-1 and HvNAM-2 and with grain protein content was found. Conclusions In contrast to studies in wheat, where a strong negative correlation between straw length and grain protein and micronutrient content has been found, we do not see this relationship in Nordic barley. The last 60 years of breeding has reduced straw length but, contrary to expectations, not protein and micronutrient content. Variation in grain protein and micronutrient content was found among the Nordic barley accessions, but it is not explained by variation of HvNAM genes. This means that HvNAM is an unexploited source of genetic variation for nutrient content in Nordic barley.
The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science–policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science–policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science–policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.
Localized morphological discontinuities are essential features in topographic maps and aid in reading terrain from a map. The present study proposes specific procedures for cartographic generalization of discontinuities on medium-scale topographic maps. Localized morphological discontinuity is defined as a location where the grade of the terrain changes discontinuously. Localized morphological discontinuity is indicated by a contour line which contains small, consecutive lines extending to its right side. Approximately 5% of localized morphological discontinuities do not collide with other elements. After performing our generalization procedures, a significant number of discontinuities conformed with constraints consisting of localized morphological discontinuity parallel to or aligned with other line features (roads, tracks, rivers, or outlines of land-use boundaries). The procedure employs two components: a database and a plugin. The database was implemented in PL/pgSQL and C, and the plugin (ArcGIS Pro plugin) was implemented in C# using.NET. Processing resolved 70% of discontinuities which were in collision. The article discusses various aspects of this generalization procedure.
Background: Providing palliative care at the end of life (EOL) in intensive care units (ICUs) seems to be modified during the COVID-19 pandemic with potential burden of moral distress to health care providers (HCPs). We seek to assess the practice of EOL care during the COVID-19 pandemic in ICUs in the Czech Republic focusing on the level of moral distress and its possible modifiable factors. Methods: Between 16 June 2021 and 16 September 2021, a national, cross-sectional study in intensive care units (ICUs) in Czech Republic was performed. All physicians and nurses working in ICUs during the COVID-19 pandemic were included in the study. For questionnaire development ACADEMY and CHERRIES guide and checklist were used. A multivariate logistic regression model was used to analyse possible modifiable factors of moral distress. Results: In total, 313 HCPs (14.5% out of all HCPs who opened the questionnaire) fully completed the survey. Results showed that 51.8% (n = 162) of respondents were exposed to moral distress during the COVID-19 pandemic. 63.1% (n = 113) of nurses and 71.6% of (n = 96) physicians had experience with the perception of inappropriate care. If inappropriate care was perceived, a higher chance for the occurrence of moral distress for HCPs (OR, 1.854; CI, 1.057-3.252; p = 0.0312) was found. When patients died with dignity, the chance for moral distress was lower (OR, 0.235; CI, 0.128-0.430; p < 0.001). The three most often reported differences in palliative care practice during pandemic were health system congestion, personnel factors, and characteristics of COVID-19 infection. Conclusions: HCPs working at ICUs experienced significant moral distress during the COVID-19 pandemic in the Czech Republic. The major sources were perceiving inappropriate care and dying of patients without dignity. Improvement of the decision-making process and communication at the end of life could lead to a better ethical and safety climate. Trial registration: NCT04910243 .
Suppose that R (red) and B (blue) are two graphs on the same vertex set of size n, and H is some graph with a red-blue coloring of its edges. How large can R and B be if R∪B does not contain a copy of H? Call the largest such integer mex(n,H). This problem was introduced by Diwan and Mubayi, who conjectured that (except for a few specific exceptions) when H is a complete graph on k+1 vertices with any coloring of its edges mex(n,H)=ex(n,Kk+1). This conjecture generalizes Turán's theorem. Diwan and Mubayi also asked for an analogue of Erdős-Stone-Simonovits theorem in this context. We prove the following upper bound on the extremal threshold in terms of the chromatic number χ(H) and the reduced maximum matching number M(H) of H.mex(n,H)≤(1−12(χ(H)−1)−M(H)9χ(H)2)n22. M(H) is, among the set of proper χ(H)-colorings of H, the largest set of disjoint pairs of color classes where each pair is connected by edges of just a single color. The result is also proved for more than 2 colors and is tight up to the implied constant factor. We also study mex(n,H) when H is a cycle with a red-blue coloring of its edges, and we show that mex(n,H)≲12(n2), which is tight.
Several important loess sections containing marine isotope stage 3 palaeosols have been discovered in the area of the Bohunice district of the city of Brno. Most of them were previously examined mainly from an archaeological point of view in relation to the Middle/Upper Palaeolithic transition, and their palaeopedological records were not studied in detail. The term ‘Bohunician soil’ was introduced during the initial archaeological research of the Brno-Bohunice site and has since been used to refer to palaeosols containing Bohunician artefacts in the surrounding region without any clear definition of what the term actually means. A newly exposed loess section (Brno-Bohunice 2018) and a preserved section from the last archaeological research (Brno-Bohunice 2002) provide an opportunity to revise the Brno-Bohunice palaeosol record and to assess the reasonability of the term ‘Bohunician soil’. We present a comprehensive multiproxy evaluation of soil development over the period of 60–30 ka BP, based on a combination of soil micromorphology and physical and geochemical proxies. The oldest recorded soil horizon was identified below the originally recognized ‘Lower palaeosol’ in the 2002 section whereas in the 2018 section the oldest horizon is of colluvial origin. We newly classify the ‘Lower palaeosol’ as a Cambisol and Tundra gley and interpret the ‘Upper palaeosol’ as a Regosol. Our new division and reassessment of dating results shows that the majority of the Bohunician artefacts found mostly at the transition between the Cambisol and Tundra gley were not in their original stratigraphic position. They were probably lifted by freezing-thawing processes from an earlier position between the soliflucted soil horizon and the Cambisol. It is likely that even in the first excavated contexts of so-called Bohunician soil, artefacts were not necessarily found in their original position. The term therefore appears to have no relevance.
2-nondegenerate real hypersurfaces in complex manifolds play an important role in CR-geometry and the theory of Hermitian Symmetric Domains. In this paper, we obtain a complete convergent normal form for everywhere 2-nondegenerate real-analytic hypersurfaces in complex 3-space. We do so by entirely reproducing the Chern-Moser theory in the 2-nondegenerate setting. This seems to be the first such construction for hypersurfaces of infinite Catlin multitype. We in particular discover chains in an everywhere 2-nondegenerate hypersurface, the tangent lines to which at a point form the so-called canonical cone. Our approach is based on using a rational (nonpolynomial) model for everywhere 2-nondegenerate hypersurfaces, which is the local realization due to Fels-Kaup of the well known tube over the light cone. For the convergence of the normal form, we use an argument due to Zaitsev, based on building a canonical direction field in an appropriate bundle over a hypersurface. As an application, we obtain, in the spirit of Chern-Moser theory, a criterion for the local sphericity (i.e. local equivalence to the model) for a 2-nondegenerate hypersurface in terms of its normal form. As another application, we obtain an explicit description of the moduli space of everywhere 2-nondegenerate hypersurfaces.
The linear homotopy theory for codifferential operator on Riemannian manifolds is developed in analogy to a similar idea for exterior derivative. The main object is the cohomotopy operator, which singles out a module of anticoexact forms from the module of differential forms defined on a star-shaped open subset of a manifold. It is shown that there is a direct sum decomposition of a differential form into coexact and anticoexat parts. This decomposition gives a new way of solving exterior differential systems. The method is applied to equations of fundamental physics, including vacuum Dirac-Kähler equation, coupled Maxwell-Kalb-Ramond system of equations occurring in a bosonic string theory and its reduction to the Dirac equation.
We prove a conjecture by Garbe et al. [arXiv:2010.07854] by showing that a Latin square is quasirandom if and only if the density of every pattern is . This result is the best possible in the sense that cannot be replaced with or for any n.
Objective This systematic review and meta-analysis aimed to analyze and synthesize the evidence on the effectiveness of virtual reality (VR) interventions in the prevention of pain, fear and anxiety during burn wound care procedures. Methods In September and October 2021, PubMed, Scopus, Cochrane Library and Web of Science were searched for relevant randomized controlled and crossover studies. Two independent authors described the following inclusion criteria for the search: patients undergoing burn wound care with applied VR treatment compared to any other or non-VR intervention. From a total of 1171 records, 25 met the inclusion criteria. After full-text screening, seven publications were excluded. The risk of bias was assessed for 18 studies by two independent authors. RevMan 5.4 was used for the statistical analysis, meta-analysis and visual presentation of the results. Results The meta-analysis showed a significant difference between VR treatment and standard care when analyzing pain outcome during wound care procedures (SMD = −0.49; 95% CI [−0.78, −0.15]; I² = 41%) and in subgroup analysis when immersive VR was incorporated (SMD = −0.71; 95% CI [−1.07, −0.36]; I² = 0%). No significant differences were found between VR treatment and standard care for range of motion outcome (SMD = 0.44; 95% CI [−0.23, 1.11]; I² = 50%). Conclusions VR seems to be an effective therapeutic support in burn wound care procedures for reducing pain. However, this systematic review and meta-analysis highlights the need for more research into the use of VR as a distraction method. Studies on larger groups using similar conditions can provide unequivocal evidence of the effectiveness of VR and enable the inclusion of such intervention in standard medical procedures.
We study the infinitesimal CR automorphisms of polynomial model hypersurfaces of finite multitype, which violates 2-jet determination. We give an exposition of some recent results, which provide explicit description of such “exotic” symmetries in complex dimension three. The results are illustrated by numerous examples.
Social voles of the genus Microtus consist of at least eight nominal species occurring in the Western Palearctic. Despite the significant influence of Middle Eastern Geo-climatic heterogeneity on small mammal diversification, this area remains largely unexplored. In this study, we considered mitochondrial cytochrome b phylogeny and chromosomal data to assess taxonomy and intraspecific variability within two closely related social voles, Microtus irani and Microtus schidlovskii in the Middle East. We also performed univariate and multivariate analyses to elucidate the craniodental variations between the studied voles. We confirmed the close relationship of the “irani-schidlovskii” complex while providing pieces of evidence for their distinct species’ status. In addition, our new material from Iran outlines a novel view on the distribution of the taxonomically obscure Iranian vole M. irani with an undescribed subspecies from Chahar-Mahal & Bakhtiari Province in southwestern Iran.
We analyzed per- and polyfluoroalkyl substances (PFAS) in aqueous film-forming foams (AFFFs) used to extinguish a major fire in a petrochemical terminal from the Port of Santos (Brazil). Eight AFFFs from seven known commercial brands and one unknown sample (AFFF-1 to AFFF-8) were evaluated. 17 PFAS were identified and quantified using high performance liquid chromatography (LC/MS). The concentrations of Σ17 PFAS in the AFFFs ranged from 500 to 9000 ng/g, with prevalence of short chain PFAS (~85 %), followed by long chain PFAS. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), included in the global treaty of the Stockholm Convention, were also detected. We estimated that at least 635.96 g of PFAS were introduced in the estuary, representing a massive input of these substances. This investigation reports the PFAS composition of AFFFs used in firefighting in the GRULAC Region (Group of Latin American and Caribbean countries).
By invading Ukraine and weaponizing its gas supplies to Europe, Russia has made natural gas what renewable energy used to be: unreliable and expensive. In this perspective, we use the paradigm shift concept developed by Florian Kern et al. to unpack the possible implications of the war for the European energy politics. We argue that the war and the uncertainty around natural gas it has produced will play a major role in the future development of the European energy transition. Reducing energy vulnerability and faster decarbonization will be pursued as the main policy goals, probably at the expense of the further development of the EU integrated energy market under its current design. We may also see more Europe and more state in the energy affairs as solutions to the crisis require levels of coordination and resource mobilization that individual member states or private actors cannot provide. We conclude that the EU has the resources, knowledge base, and determination to turn the crisis into an opportunity. If uncoordinated or mismanaged, however, the European response might make the matters even worse, triggering a political crisis and eventually also a crisis of legitimacy.
Methylglyoxal (MG) production after myocardial infarction (MI) leads to advanced glycation end‐product formation, adverse remodeling, and loss of cardiac function. The extracellular matrix (ECM) is a main target for MG glycation. This suggests that ECM‐mimicking biomaterial therapies may protect the post‐MI environment by removing MG. In this study, mechanisms by which a recombinant human collagen type I hydrogel therapy confers cardioprotection are investigated. One‐week post‐MI, mice receive intramyocardial injection of hydrogel or PBS. The hydrogel improves border zone contractility after 2 days, which is maintained for 28 days. RNA sequencing shows that hydrogel treatment decreases the expression of erythroid differentiation regulator 1, a factor associated with apoptosis. Hydrogel treatment reduces cardiomyocyte apoptosis and oxidative stress at 2 days with greater myocardial salvage seen at 28 days. The hydrogel located at the epicardial surface is modified by MG, and less MG‐modified proteins are observed in the underlying myocardium of hydrogel‐treated mice. Biomaterials that can be a target for MG glycation may act as a sponge to remove MG from the myocardium post‐MI. This leads to less oxidative stress, greater survival and contractility of cardiomyocytes, which altogether suggests a novel mechanism by which biomaterials improve function of the infarcted heart.
Background Melissiodon is a rare cricetid genus endemic to Europe, known from the Early Oligoceneto the Early Miocene. It is usually a very rare find, and even in the few localities where Melissiodon remains are found, those are scarce and fragmentary. Only a few Central European localities have yielded rich remains of the genus. Currently, two species are known from the Early Miocene: Melissiodon schlosseri, which is based on two teeth from the MN2 German locality of Haslach and only found in two other sites of similar age (Ulm-Uniklinik and La Chaux, from Germany and Switzerland respectively); and Melissiodon dominans, found in MN3 and MN4 localities across Europe, even though the scarce and fragmentary remains make some of these attributions dubious. For that reason, Melissiodon dominans has become a catch-all species. However, Mokrá-Quarry represents one of the best documented findings of Melissiodon remains from MN4 localities of Europe. Methods The Melissiodon assemblage from Mokrá-Quarry has been studied thoroughly, providing metrics and detailed descriptions of all teeth positions, as well as complete comparisons with other MN3 and MN4 localities bearing Melissiodon remains. Results In this work, new remains of Melissiodon have been identified as a new morphotype that clearly differs from Melissiodon dominans by its unique m1 morphology but still shows some resemblance with Melissiodon schlosseri. Based on that, we here propose the hypothesis of an evolutionary lineage starting from Melissiodon schlosseri , diverging from the lineage leading towards Melissiodon dominans. With this finding, there are at least two different taxa of Melissiodon known during the Early Miocene, prior to the genus extinction. This study arises the certainty that the evolution history of the genus is more complex than previously thought and that more studies are necessary to elucidate it, including a complete revision of the type material of Melissiodon dominans and Melissiodon schlosseri in the light of current knowledge of the genus, which will help to elucidate the attribution of the populations from Mokrá-Quarry. For the time being, the assemblage presented here is referred as Melissiodon aff. schlosseri.
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14,226 members
Martin Guzi
  • Department of Public Economics
Miroslav Kralik
  • Department of Anthropology
Frantisek Zedek
  • Department of Botany and Zoology
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