Eötvös Loránd University
Recent publications
Dioximes as ligands are used as analytical reagents and serve as models for biological systems as well as catalysts in chemical processes. A number of novel mixed complexes of the type [Fe(DioxH) 2 (amine) 2 ] have been prepared and characterised by FTIR, ⁵⁷ Fe Mössbauer and mass spectroscopy by us. We have found strong Fe–N donor acceptor interactions and iron occurred in low-spin Fe II state in all complexes. Later, we have also found that the incorporation of branching alkyl chains (isopropyl) in the complexes alters the Fe–N bond length and results in high-spin iron(II) state [1, 2]. The question arises: can the spin state of iron be manipulated generally by replacing the short alkyl chains with high volume demand ones in Fe-azomethine-amine complexes? To answer the question we have synthetized novel iron-bis-glioxime and iron-tris-gloxime complexes when long chain alkyl or aromatic ligands replaced the short alkyl ones and studied by ⁵⁷ Fe Mössbauer spectroscopy, MS, FTIR, UV-VIS, TG-DTA-DTG and XRD methods. Novel iron-bis-glyoxime and iron-tris-glyoxime type complexes, [Fe(Diethyl-Diox) 3 (BOH) 2 ], [Fe(Diethyl-Diox) 3 (BOEt) 2 ] and [Fe(phenyl-Me-Diox) 3 (BOEt) 2 ], were synthesized similarly as described in [2]. The FTIR, UV-VIS, TG-DTA-DTG and MS measurements indicated that the expected novel complexes could be successfully synthesized.
The reconstruction of the trajectories of charged particles, or track reconstruction, is a key computational challenge for particle and nuclear physics experiments. While the tuning of track reconstruction algorithms can depend strongly on details of the detector geometry, the algorithms currently in use by experiments share many common features. At the same time, the intense environment of the High-Luminosity LHC accelerator and other future experiments is expected to put even greater computational stress on track reconstruction software, motivating the development of more performant algorithms. We present here A Common Tracking Software (ACTS) toolkit, which draws on the experience with track reconstruction algorithms in the ATLAS experiment and presents them in an experiment-independent and framework-independent toolkit. It provides a set of high-level track reconstruction tools which are agnostic to the details of the detection technologies and magnetic field configuration and tested for strict thread-safety to support multi-threaded event processing. We discuss the conceptual design and technical implementation of ACTS, selected applications and performance of ACTS, and the lessons learned.
Increasing evidence points towards the key role of the epithelium in the systemic and over-activated immune response to viral infection, including SARS-CoV-2 infection. Yet, how viral infection alters epithelial–immune cell interactions regulating inflammatory responses, is not well known. Available experimental approaches are insufficient to properly analyse this complex system, and computational predictions and targeted data integration are needed as an alternative approach. In this work, we propose an integrated computational biology framework that models how infection alters intracellular signalling of epithelial cells and how this change impacts the systemic immune response through modified interactions between epithelial cells and local immune cell populations. As a proof-of-concept, we focused on the role of intestinal and upper-airway epithelial infection. To characterise the modified epithelial–immune interactome, we integrated intra- and intercellular networks with single-cell RNA-seq data from SARS-CoV-2 infected human ileal and colonic organoids as well as from infected airway ciliated epithelial cells. This integrated methodology has proven useful to point out specific epithelial–immune interactions driving inflammation during disease response, and propose relevant molecular targets to guide focused experimental analysis.
Introduction: According to Borbély (1982) a homeostatic and a circadian process define the main aspects of sleep regulation. Although slow wave activity of the sleep EEG is a widely accepted marker of sleep homeostasis, high frequency activity is also changing throughout the night (in the opposite direction). Thus, the ratio of lower to higher frequencies in the EEG power spectrum seems to be a more accurate indicator of sleep homeostasis. In addition, sleep spindle frequency could be a suitable marker of the circadian process since it was shown to follow a U-shaped overnight dynamic and its dampening in aged subjects. Given the linear association between the logarithm of frequency and logarithm of amplitude the Fourier spectrum can be described by an approximation of the parameters of the following function: P(f) =C*f^α*PˇPeak(f), where P is power as a function of frequency, C is the constant, α is the spectral exponent which shows the ratio of different frequencies in the signal, and PˇPeak is the peak power at frequency f. We hypothesized that (i) Pˇpeak(f) values of the sleep spindle range (9-18 Hz) are higher in the last and first sleep cycles than in the middle parts of night sleep records, (ii) spindle deceleration in the middle of the night is modulated by age, while (iii) α is decreasing linearly across the night as the sleep pressure decays (spectral slope flattening). Materials and Methods: Artefact-free NREM sleep periods of successive cycles in the Budapest-Munich database of sleep records (N = 251 healthy subjects, 122 females, age range: 4–69 years) were analysed by FFT routine and power spectrum obtained for selected EEG derivations. Furthermore, the log-log power was fitted with a linear, and a peak detection was applied in the 9-18 Hz (broad sleep spindle) range at derivations O2, O1, P4, P3, C4, C3, F4, F3, Fp2, Fp1. Statistical analysis was based on general linear models. Results: The NREM sleep EEG spectral exponents (α) increased in consecutive sleep cycles (absolute values decreased), and this effect was significant at all derivations. The maximum peak frequency was significantly modulated by age at all derivations and by cycle at O2, P4, P3, C4, F4, F3, Fp1. There was a cycle x age group interaction at derivations O2 and F3. A tendency for the U-shaped dynamic throughout the sleep cycles was seen at all derivations. Conclusions: Our results show that the spectral exponent is a potent marker of the homeostatic process of sleep regulation which supports earlier findings about the associations between this exponent and sleep depth. Furthermore, the maximum spectral peak frequencies could reflect the circadian modulation of sleep. The latter index could be a useful measure in future studies, potentially substituting complicated protocols like melatonin or core body temperature measurements, with assumed applicability in retrospective investigations. Finally, the spectral exponent can serve as a link between sleep regulation and consciousness.
A necklace can be considered as a cyclic list of n red and n blue beads in an arbitrary order. In the necklace folding problem the goal is to find a large crossing-free matching of pairs of beads of different colors in such a way that there exists a “folding” of the necklace, that is a partition into two contiguous arcs, which splits the beads of any matching edge into different arcs. We give counterexamples for some conjectures about the necklace folding problem, also known as the separated matching problem. The main conjecture (given independently by three sets of authors) states that μ=23, where μ is the ratio of the maximum number of matched beads to the total number of beads. We refute this conjecture by giving a construction which proves that μ≤2−2<0.5858≪0.66. Our construction also applies to the homogeneous model when we match beads of the same color. Moreover, we also consider the problem where the two color classes do not necessarily have the same size.
In this paper we show the first polynomial-time algorithm for the problem of minimizing submodular functions on the product of diamonds of finite size. This submodular function minimization problem is reduced to the membership problem for an associated polyhedron, which is equivalent to the optimization problem over the polyhedron, based on the ellipsoid method. The latter optimization problem is a generalization of the weighted fractional matroid matching problem. We give a combinatorial polynomial-time algorithm for this optimization problem by extending the result by Gijswijt and Pap (2013) [9].
Low-temperature solid-state reactions between Ni and Si were studied using in situ transmission electron microscopy (TEM). In the experiments thin amorphous silicon (a-Si) films were laid on Ni micro-grids and heated up to 973 K. In our approach the supporting Ni-grid serves as an unlimited source of nickel to successively form the whole range of Ni-silicide phases while diffusing into amorphous silicon. Unlike other thin film experiments where Ni and Si are layered on top of each other, our arrangement enables lateral diffusion of Ni along the Si layer and therefore enables the formation and study of successive Ni-Si phases side by side. That allowed us to observe in situ α-NiSi2 as the first reaction product, in contrast to most studies that had reported either δ-Ni2Si or θ-Ni2Si as the first phase to form. α-NiSi2 was continuously present at the reaction front propagating into the a-Si film. The phase sequence followed the increasing Ni concentration from a-Si towards the Ni-grid: α-NiSi2, NiSi, Ni3Si2, δ-Ni2Si, γ-Ni31Si12 and Ni3Si. Almost all known Ni-silicide phases were found to form at relatively low temperatures except the θ-Ni2Si, β-NiSi2 and β3-Ni3Si. The dominant phase was γ-Ni31Si12 which appeared in three structural modifications, differing in lattice periodicity along the c-axis. The periodicity of the basic γ-Ni31Si12 structure along the c-axis is ~12 Å (c0 = 12.288 Å) and that of the other two modifications were ~18 Å and ~36 Å, denoted by S12, S18 and S36 respectively. Of the three, only S12 has a structural model, S18 had been previously observed by Chen, but S36 had not been documented in previous works. During our in situ heating experiments, in addition to the Ni-silicide layer formation a new phenomenon was observed, namely the appearance, growth and transformation of Ni-silicide whiskers which was attributed to the accumulation of compressive stress in the thin layer.
In this paper we study optimal investment when the investor can peek some time units into the future, but cannot fully take advantage of this knowledge because of quadratic transaction costs. In the Bachelier setting with exponential utility, we give an explicit solution to this control problem with intrinsically infinite-dimensional memory. This is made possible by solving the dual problem where we make use of the theory of Gaussian Volterra integral equations.
Integer-valued elements of an integral submodular flow polyhedron Q are investigated which are decreasingly minimal (dec-min) in the sense that their largest component is as small as possible, within this, the second largest component is as small as possible, and so on. As a main result, we prove that the set of dec-min integral elements of Q is the set of integral elements of another integral submodular flow polyhedron arising from Q by intersecting a face of Q with a box. Based on this description, we develop a strongly polynomial algorithm for computing not only a dec-min integer-valued submodular flow but even a cheapest one with respect to a linear cost-function. A special case is the problem of finding a strongly connected (or k-edge-connected) orientation of a mixed graph whose in-degree vector is decreasingly minimal.
After the last glacial, the Carpathian Basin was repopulated from either eastward or northward colonisation routes for various species; one of these was the emblematic member of the European megafauna, the red deer, Cervus elaphus. We analysed 303 red deer individuals from the middle of the region, in seven Hungarian game reserves, at ten microsatellite loci (C01, C229, T26, T108, T123, T156, T172, T193, T501, T507), to investigate the genetic diversity of these subpopulations. We discovered high levels of genetic diversity of red deer subpopulations; allelic richness values ranging 4.99-7.01, observed heterozygosity 0.729-0.800, polymorphic information content 0.722-0.806, and Shannon's information index 1.668-2.064. Multi-locus analyses indicated population admixtures of various degrees that corresponded to geographical location, and complex genetic structures were shown by clustering. Populations in the southwestern and the northeastern parts of the region formed two highly separated groups, and the red deer from populations in between them were highly admixed (in western Pannonia/Transdanubia, where the Danube flows into the Carpathian Basin). This pattern corresponds to the distribution of mitochondrial as well as Y-chromosome lineages. Assignment tests showed that a large fraction of individuals (29.4%) are found outside of their population of origin, indicating that the dispersal of red deer is rather common, which could be expected considering the life course of the species.
Control charts originate from industrial statistics, but are constantly seeing new areas of application, for example in health care (Thor et al. in BMJ Qual Saf 16(5):387–399, 2007. https://doi.org/10.1136/qshc.2006.022194 ; Suman and Prajapati in Int J Metrol Qual Eng, 2018. https://doi.org/10.1051/ijmqe/2018003 ). This paper is about the package, an implementation of generalised Markov chain-based control charts with health care applications in mind and with a focus on cost-effectiveness. The methods are based on Zempléni et al. (Appl Stoch Model Bus Ind 20(3):185–200, 2004. https://doi.org/10.1002/asmb.521 ), Dobi and Zempléni (Qual Reliab Eng Int 35(5):1379–1395, 2019a. https://doi.org/10.1002/qre.2518 , Ann Univ Sci Budapestinensis Rolando Eötvös Nomin Sect Comput 49:129–146, 2019b). The implemented ideas in the package were motivated by problems encountered by health care professionals and biostatisticians when assessing the effects and costs of different monitoring schemes and therapeutic regimens. However, the implemented generalisations may be useful in other (e.g., engineering) applications too, as they mainly revolve around the loosening of assumptions seen in traditional control chart theory. The package is able to model processes with random shift sizes (i.e., the degradation of the patient’s health), random repair (i.e., treatment) and random time between samplings (i.e., visits) as well. The article highlights the flexibility of the methods through the modelling of different disease progression and treatment scenarios and also through an application on real-world data of diabetic patients.
The aim of this study is to investigate the importance of family cohesion and self-esteem regarding test anxiety among emerging adults. The study’s hypothesis is that cohesion experienced in a university student’s family of origin predicts test anxiety. The mediating role of self-esteem was tested considering both global self-esteem and contingent self-esteem based on one’s perceived competence. The study also examines whether these associations differ across groups based on gender or residential status. The research questions were investigated using students’ self-reported measures of test anxiety, global self-esteem, contingent self-esteem, and family cohesion. The results, based on data gathered from 487 university students, revealed that global self-esteem was a negative predictor of test anxiety and contingent self-esteem was a positive predictor of test anxiety. These findings indicate that the level and source of self-esteem must be considered regarding test anxiety. Further, adaptive family cohesion impacted test anxiety by increasing global self-esteem and decreasing contingent self-esteem. Although these indirect associations were rather weak, they highlight the impact of the family of origin during emerging adulthood. The pattern of interrelations was similar among men and women, as well as among those living together or apart from their family of origin.
Mate choice appears to be driven by a set of mate preferences. It is, however, unclear how preferences for individual characteristics are integrated into actual mate choice decisions. According to the Additive model, the most desirable partner is the one with the highest overall sum of relevant characteristics. In contrast, the Threshold model predicts that only partners who meet a certain threshold value in all characteristics will be considered. We conducted two studies (Pilot: N = 522, and Main Study: N = 1873) to compare the two models using vignettes describing potential partners. Each vignette was predicted to be preferred either by the Additive or by the Threshold model. Overall, participants preferred the vignettes following the Threshold model, except if the violated characteristic had low importance. Our results indicate that in mate choice, decisions are directed by thresholds in preferences but take also into account the overall sum of the relevant characteristics.
We consider a natural generalization of Turán's forbidden subgraph problem and the Ruzsa-Szemerédi problem by studying the maximum number exF(n,G) of edge-disjoint copies of a fixed graph F can be placed on an n-vertex ground set without forming a subgraph G whose edges are from different F-copies. We determine the pairs {F,G} for which the order of magnitude of exF(n,G) is quadratic and prove several asymptotic results using various tools from the regularity lemma and supersaturation to graph packing results.
Growing incidence of nonsuicidal self-injury (NSSI) and a lack of intensive examination of NSSI variability among adolescents justify identification of latent classes based on the endorsement of different NSSI behaviors. Latent class analysis was used to detect the heterogeneity of past month NSSI among 322 high school students (73.2% female). Two interpretable latent classes emerged. The Severe/Multimethod NSSI class (39%) engaged in almost all forms of NSSI with high intensity and motivated mainly for intrapersonal reasons. The results imply that compared to Mild/Moderate NSSI group (61%), the Severe class is at greater risk for poor mental health, which can exacerbate further NSSI acts. In school settings, identifying adolescents who are vulnerable for more severe NSSI can help to interrupt NSSI trajectories to emerging adulthood.
A conjecture of Erdős from 1967 asserts that any graph on n vertices which does not contain a fixed r-degenerate bipartite graph F has at most Cn2−1/r edges, where C is a constant depending only on F. We show that this bound holds for a large family of r-degenerate bipartite graphs, including all r-degenerate blow-ups of trees. Our results generalise many previously proven cases of the Erdős conjecture, including the related results of Füredi and Alon, Krivelevich and Sudakov. Our proof uses supersaturation and a random walk on an auxiliary graph.
Previous research has repeatedly shown a positive association between the need for relationship security and the appeal of benevolent sexism. Possibly, no studies to date had investigated the role of the need to belong with respect to a preference for the ideal partner to endorse benevolently sexist attitudes. Attachment security is considered to attenuate the need for relationship security and to divert the focus from the need to belong. Study 1 therefore investigated potential associations among attachment anxiety, the need to belong, and the appeal of benevolent sexism. It also examined whether the association between the need to belong and a preference for the ideal partner to hold benevolently sexist attitudes is moderated by attachment anxiety. In Study 2, we used a causal design to confirm the findings from Study 1 through the activation of attachment security schema. A moderated regression analysis showed significant interactive effects between the need to belong and attachment anxiety—that is, a positive association between the need to belong and the appeal of benevolent sexism was found only among people high in attachment anxiety. Secure-base scripts attenuated the need to belong as well as the appeal of benevolent sexism. The present findings suggest the importance of attachment schemas in influencing preference for specific partner attitudes through the need to belong and relationship security.
In the present study, the bacterial community structure of enrichment cultures degrading benzene under microaerobic conditions was investigated through culturing and 16S rRNA gene Illumina amplicon sequencing. Enrichments were dominated by members of the genus Rhodoferax followed by Pseudomonas and Acidovorax . Additionally, a pale amber-coloured, motile, Gram-stain-negative bacterium, designated B7 T was isolated from the microaerobic benzene-degrading enrichment cultures and characterized using a polyphasic approach to determine its taxonomic position. The 16S rRNA gene and whole genome-based phylogenetic analyses revealed that strain B7 T formed a lineage within the family Comamonadaceae, clustered as a member of the genus Ideonella and most closely related to Ideonella dechloratans CCUG 30977 T . The sole respiratory quinone is ubiquinone-8. The major fatty acids are C 16:0 and summed feature 3 (C 16:1 ω 7c/iso-C 15:0 2-OH). The DNA G + C content of the type strain is 68.8 mol%. The orthologous average nucleotide identity (OrthoANI) and in silico DNA–DNA hybridization (dDDH) relatedness values between strain B7 T and closest relatives were below the threshold values for species demarcation. The genome of strain B7 T , which is approximately 4.5 Mb, contains a phenol degradation gene cluster, encoding a multicomponent phenol hydroxylase (mPH) together with a complete meta -cleavage pathway including a I.2.C-type catechol 2,3-dioxygenase ( C23O ) gene. As predicted by the genome, the type strain is involved in aromatic hydrocarbon-degradation: benzene, toluene and ethylbenzene are degraded aerobically and also microaerobically as sole source of carbon and energy. Based on phenotypic characteristics and phylogenetic analysis, strain B7 T is a member of the genus Ideonella and represents a novel species for which the name Ideonella benzenivorans sp. nov. is proposed. The type strain of the species is strain B7 T (= LMG 32,345 T = NCAIM B.02664 T ).
The stability of target compounds under migration conditions is scarcely investigated. To provide data for better regulations and guidelines, the stability of 24 primary aromatic amines (PAAs) was investigated under several storage conditions in all aqueous food simulants of Commission Regulation No. 10/2011. Eleven carcinogenic PAAs appeared to be less stable under at least one of the investigated conditions. PAAs appeared to be the least stable in 3% (m/V) acetic acid. This is highly problematic because this food simulant represents the worst-case scenario regarding PAA migration testing. Since 3 mmolL⁻¹ HCl solution with similar pH showed that PAAs were more stable in this medium we suggest its consideration as an alternative food simulant. In ethanol containing food simulants, most PAAs proved to be stable. Decreased temperature improved PAA stability, whereas shortened storage time improved PAA recovery.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
7,471 members
Gábor Timár
  • Department of Geophysics and Space Sciences
Bálint Halpern
  • Department of Systematic Zoology and Ecology
Ildiko Pap
  • Department of Biological Anthropology
Agnes N. TOTH
  • Faculty of Education and Psychology
Peter Simor
  • Department of Affective Psychology
Egyetem tér 1-3, H-1053, Budapest, Hungary
Head of institution
prof. László Borhy, rector
+36 1 4116500