Publications by authors named "Balog R"

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  • Most 2D materials studied are hexagonal, but researchers have successfully created a metastable pentagonal 2D material called monolayer pentagonal PdTe.
  • This material was synthesized using symmetry-driven epitaxy and characterized through scanning tunneling microscopy and spectroscopy, showing stable low-symmetry atomic structures.
  • Theoretical analyses suggest that monolayer pentagonal PdTe is a semiconductor with a 1.05 eV indirect bandgap, paving the way for future pentagon-based 2D materials and their potential applications in nanoelectronics.
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Prenatal experiences can influence offspring physiology and behaviour through the lifespan. Various forms of prenatal stress impair adult learning and memory function and can lead to increased occurrence of anxiety and depression. Clinical work suggests that prenatal stress and maternal depression lead to similar outcomes in children and adolescents, however the long-term effects of maternal depression are less established, particularly in well controlled animal models.

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  • The study explores how hydrogenated graphene interacts with an Ir(111) substrate using advanced X-ray techniques, revealing unique absorption profiles and signal intensity changes.
  • The researchers refine C 1s X-ray photoelectron spectra to differentiate the effects of hydrogenation in various high-symmetry areas of the graphene structure.
  • Results indicate that hydrogenation mainly affects FCC regions, creating a graphane-like structure, while contributions from dimer structures in ATOP regions are minimal, challenging previous assumptions about their significance.
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Interesting electronic properties arise in vertically stacked graphene sheets, some of which can be controlled by mutual orientation of the adjacent layers. In this study, we investigate the MBE grown multilayer graphene on Ir(111) by means of STM, LEED and XPS and we examine the influence of the substrate on the geometric and electronic properties of bilayer graphene by employing XSW and ARPES measurements. We find that the MBE method does not limit the growth to two graphene layers and that the wrinkles, which arise through extended carbon deposition, play a crucial role in the multilayer growth.

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The principles and mechanisms of adsorption of Ni(ii) ions by well characterized pristine and oxidized N-doped multi-walled carbon nanotubes (N-CNTs) are described and discussed. The samples were synthesized by CCVD method using -butylamine as the carbon source and Ni(NO) + MgO as the catalyst and purified by treatment with HCl. The surface functionalization was performed using oxidation with a mixture of concentrated HSO and HNO.

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Functionalization of graphene on Ir(111) is a promising route to modify graphene by chemical means in a controlled fashion at the nanoscale. Yet, the nature of such functionalized sp3 nanodots remains unknown. Density functional theory (DFT) calculations alone cannot differentiate between two plausible structures, namely true graphane and substrate stabilized graphane-like nanodots.

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  • A new procedure was developed to create a hydrogen-intercalated graphene layer that is chemically separated from its metal substrate.
  • Using advanced techniques like x-ray photoelectron spectroscopy and scanning tunneling microscopy, it was found that this hydrogen-intercalated graphene has a p-doping level of about 0.28 eV and features interfacial hydrogen structures.
  • The study also analyzed how the decoupled graphene layer reacts with atomic and vibrationally excited molecular hydrogen, finding significant differences when compared to non-intercalated graphene and the potential formation of graphane clusters on iridium substrates.
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: In a significant nuclear event, hundreds of thousands of individuals will require rapid triage for absorbed radiation to ensure effective medical treatment and efficient use of medical resources. We are developing a rapid screening method to assess whether an individual received an absorbed dose of ≥2 Gy based on the analysis of a specific panel of blood proteins in a fingerstick blood sample.: We studied a data set of 1051 human blood samples obtained from radiotherapy patients, normal healthy individuals, and several special population groups.

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There is a need to rapidly triage individuals for absorbed radiation dose following a significant nuclear event. Since most exposed individuals will not have physical dosimeters, we are developing a method to assess exposure dose based on the analysis of a specific panel of blood proteins that can be easily obtained from a fingerstick blood sample. In three large non-human primate (NHP) studies, animals were exposed to single acute total body doses of x-ray or gamma radiation.

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  • The study shows that strengthening interactions at the graphene-metal interface can effectively prevent unwanted foreign substances from intercalating beneath graphene coatings.
  • Graphene on Ir(111) serves as the model system, with hydrogen functionalization enhancing chemical bonds at the interface.
  • Using X-ray photoelectron spectroscopy, the research finds that this enhanced interaction can protect against significantly higher pressures and fluences of carbon monoxide compared to unmodified graphene.
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The ventral hippocampus (vHPC) has been implicated in learning and memory functions that seem to differ from its dorsal counterpart. The goal of this series of experiments was to provide further insight into the functional contributions of the vHPC. Our previous work implicated the vHPC in spatial learning, inhibitory learning, and fear conditioning to context.

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Hydrogen functionalization of graphene by exposure to vibrationally excited H molecules is investigated by combined scanning tunneling microscopy, high-resolution electron energy loss spectroscopy, X-ray photoelectron spectroscopy measurements, and density functional theory calculations. The measurements reveal that vibrationally excited H molecules dissociatively adsorb on graphene on Ir(111) resulting in nanopatterned hydrogen functionalization structures. Calculations demonstrate that the presence of the Ir surface below the graphene lowers the H dissociative adsorption barrier and allows for the adsorption reaction at energies well below the dissociation threshold of the H-H bond.

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The ability to fabricate nanoscale domains of uniform size in two-dimensional materials could potentially enable new applications in nanoelectronics and the development of innovative metamaterials. However, achieving even minimal control over the growth of two-dimensional lateral heterostructures at such extreme dimensions has proven exceptionally challenging. Here we show the spontaneous formation of ordered arrays of graphene nano-domains (dots), epitaxially embedded in a two-dimensional boron-carbon-nitrogen alloy.

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Bottom-up chemical reactions of selected molecular precursors on a gold surface can produce high quality graphene nanoribbons (GNRs). Here, we report on the formation of quantum dots embedded in an armchair GNR by substitutional inclusion of pairs of boron atoms into the GNR backbone. The boron inclusion is achieved through the addition of a small amount of boron substituted precursors during the formation of pristine GNRs.

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Band gap engineering in hydrogen functionalized graphene is demonstrated by changing the symmetry of the functionalization structures. Small differences in hydrogen adsorbate binding energies on graphene on Ir(111) allow tailoring of highly periodic functionalization structures favoring one distinct region of the moiré supercell. Scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements show that a highly periodic hydrogen functionalized graphene sheet can thus be prepared by controlling the sample temperature (T) during hydrogen functionalization.

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Alzheimer's disease (AD) is a disease of complex etiology, involving multiple risk factors. When these risk factors are presented concomitantly, cognition and brain pathology are more severely compromised than if those risk factors were presented in isolation. Reduced cholinergic tone and elevated amyloid-beta (Aβ) load are pathological hallmarks of AD.

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The recent discovery of a new class of solids displaying bulk spontaneous electric fields as high as 10(8) V m(-1), so-called 'spontelectrics', poses fundamental and unresolved problems in solid state physics. The purpose of the present work is to delve more deeply into the nature of the interactions which give rise to the spontelectric effect in films of nitrous oxide (N2O), by observing the variation of the spontaneous field as the N2O molecules are physically removed from one another by dilution in Xe. Data, obtained using the ASTRID storage ring, are presented for films diluted by factors ξ = Xe/N2O of 0.

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Purpose: To identify a panel of radiation-responsive plasma proteins that could be used in a point-of-care biologic dosimeter to detect clinically significant levels of ionizing radiation exposure.

Methods And Materials: Patients undergoing preparation for hematopoietic cell transplantation using radiation therapy (RT) with either total lymphoid irradiation or fractionated total body irradiation were eligible. Plasma was examined from patients with potentially confounding conditions and from normal individuals.

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A newly discovered class of molecular materials, so-called "spontelectrics", display spontaneous electric fields. Here we show that the novel properties of spontelectrics can be used to create composite spontelectrics, illustrating how electric fields in solid films may be structured on the nanoscale by combining layers of different spontelectric materials. This is demonstrated using the spontelectric materials nitrous oxide, toluene, isoprene, isopentane, and CF2Cl2.

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Angle-resolved photoemission spectroscopy reveals pronounced kinks in the dispersion of the σ band of graphene. Such kinks are usually caused by the combination of a strong electron-boson interaction and the cutoff in the Fermi-Dirac distribution. They are therefore not expected for the σ band of graphene that has a binding energy of more than ≈3.

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Article Synopsis
  • The introduced protocol utilizes a reconfigurable filter system to establish non-overlapping loops in smart power grids, aiming for a secure key distribution method based on Kirchhoff-Law-Johnson-(like)-Noise.
  • The focus is on one-dimensional radial networks, which resemble the chain-like structure of electricity distribution from utilities to customers.
  • The analysis of the protocol assesses its efficiency in terms of the number of steps required as the grid size increases, indicating its potential for universal security in key distribution across various smart grid geometries.
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Combined fast X-ray photoelectron spectroscopy and density functional theory calculations reveal the presence of two types of hydrogen adsorbate structures at the graphene/Ir(111) interface, namely, graphane-like islands and hydrogen dimer structures. While the former give rise to a periodic pattern, dimers tend to destroy the periodicity. Our data reveal distinctive growth rates and stability of both types of structures, thereby allowing one to obtain well-defined patterns of hydrogen clusters.

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Data are presented showing the spontaneous formation of electric fields within solid films of the chlorofluorocarbons (CFCs) CF(3)Cl, CF(2)Cl(2) and CFCl(3) as a function of film deposition temperature from 40 K and above. Electric fields, which arise through dipole alignment and lie in the range of a few times 10(7) V m(-1) to a few times 10(6) V m(-1), decrease as the degree of chlorination increases. Maximum deposition temperatures for display of an electric field lie at ~50 K, ~65 K and ~52 K for CF(3)Cl, CF(2)Cl(2) and CFCl(3) respectively.

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