269 results match your criteria: "Institute of Physics Belgrade[Affiliation]"

This study integrates proteome analysis of human breast milk (HBM) from a homogeneous group of mothers who are of similar age and live in the same geographical area, along with an analysis of essential and potentially toxic elements in HBM in relation to lifestyle and environmental factors. This preliminary proteomic study, which examined 11 samples of HBM from lactating women, identified a total of 1619 proteins across all samples, revealing significant differences in proteomes influenced by lactation stages, parity, and exposure to tobacco smoke. The pilot study aimed to explore the feasibility of correlating certain proteins with several elements, considered as indicators of tobacco smoke and environmental influences on HBM.

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In this study, we investigated the cytotoxic effect of highly soluble dextran-coated CeO nanoparticles on human fetal lung fibroblasts MRC-5. We examined individual nanoparticle-treated cells by Raman spectroscopy and analyzed Raman spectra using non-negative principal component analysis and k-means clustering. In this way, we determined dose-dependent differences between treated cells, which were reflected through the intensity change of lipid, phospholipid and RNA-related Raman modes.

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Type II restriction-modification (R-M) systems play a pivotal role in bacterial defense against invading DNA, influencing the spread of pathogenic traits. These systems often involve coordinated expression of a regulatory protein (C) with restriction (R) enzymes, employing complex feedback loops for regulation. Recent studies highlight the crucial balance between R and M enzymes in controlling horizontal gene transfer (HGT).

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Low-energy light ion beams are an essential resource in lithography for nanopatterning magnetic materials and interfaces due to their ability to modify the structure and properties of metamaterials. Here we create ferromagnetic/non-ferromagnetic heterostructures with a controlled layer thickness and nanometer-scale precision. For this, hydrogen ion (H) irradiation is used to reduce the antiferromagnetic nickel oxide (NiO) layer into ferromagnetic Ni with lower fluence than in the case of helium ion (He) irradiation.

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Photonic Bose-Einstein Condensation in the Continuum Limit.

Phys Rev Lett

November 2024

Institut für Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany.

We investigate the properties of the photon Bose-Einstein condensate in the limit of small mode spacing. Alongside the well-known threshold of the phase transition at large mode spacings, we find an emergence of a second threshold for sufficiently small mode spacings, defining the crossover to a fully condensed state. Furthermore, we present our findings for the mode occupations in the precondensate or supercooling region towards the continuum limit.

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We present the development of a custom-built structured illumination microscope (SIM) featuring a specially designed transmission diffraction grating. Employing the analog microfilming method, we fabricated transmission diffraction gratings suited to the specific requirements of our system. This robust and cost-effective method allows for the fabrication of diffraction gratings with customized constants, ensuring excellent transmission in both the visible and near-infrared spectra.

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Regime switching, the process where complex systems undergo transitions between qualitatively different dynamical states due to changes in their conditions, is a widespread phenomenon, from climate and ocean circulation, to ecosystems, power grids, and the brain. Capturing the mechanisms that give rise to isolated or sequential switching dynamics, as well as developing generic and robust methods for forecasting, detecting, and controlling them is essential for maintaining optimal performance and preventing dysfunctions or even collapses in complex systems. This Focus Issue provides new insights into regime switching, covering the recent advances in theoretical analysis harnessing the reduction approaches, as well as data-driven detection methods and non-feedback control strategies.

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Background/objectives: The aims of the presented study were the development of four types of silibinin-loaded liposomes (multilamellar liposomes-MLVs, sonicated small unilamellar liposomes-SUVs, UV-irradiated liposomes, and lyophilized liposomes) and their physicochemical characterization and biological potential related to skin health benefits.

Methods: The characterization was performed via the determination of the encapsulation efficiency (EE), particle size, polydispersity index, zeta potential, conductivity, mobility, storage stability, density, surface tension, viscosity, FT-IR, and Raman spectra. In addition, cytotoxicity on the keratinocytes and antioxidant and anti-inflammatory potential were also determined.

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Self-consistent approach to the dynamics of excitation energy transfer in multichromophoric systems.

J Chem Phys

November 2024

Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic.

Article Synopsis
  • Researchers have developed approximate methods to study exciton transport in molecular aggregates influenced by structured environments, moving beyond basic models that often become complex and hard to manage.
  • They introduced a self-consistent Born approximation to better accommodate exciton-environment interactions and improve calculations of energy transfer dynamics in these systems.
  • Their findings indicate that this new approach aligns well with more comprehensive models across various conditions, suggesting it effectively describes exciton behavior even in complex scenarios like the Fenna-Matthews-Olson complex.
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Naltrexone blocks alcohol-induced effects on kappa-opioid receptors in the plasma membrane.

Transl Psychiatry

November 2024

Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, SE-17176, Sweden.

Naltrexone (NTX), a homolog of the opiate antidote naloxone, is an orally active long-acting general opioid receptor antagonist used in the treatment of opiate dependence. NTX is also found to relieve craving for alcohol and is one of few FDA-approved medications for treatment of alcohol use disorder (AUD). While it was early on established that NTX acts by blocking the binding of endogenous opioid peptide ligands released by alcohol, experimental evidence emerged that could not be fully accounted for by this explanation alone, suggesting that NTX may have additional modes of action.

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Light on abnormal red blood cell subpopulations: Label-free optics-based approach for studying in vitro rigidified blood cells.

Spectrochim Acta A Mol Biomol Spectrosc

February 2025

Institute for Medical Research, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia. Electronic address:

RBCs deformability plays a crucial role in maintaining proper blood flow and oxygen delivery throughout the body. Conventional ektacytometry fails to differentiate between variations in deformability of RBC subpopulations as the averaging measurement process obscures these differences. In this study, we introduced an approach that integrates label-free optics-based techniques (flow cytometry, phase-contrast, and two-photon excitation fluorescent microscopy) with ektacytometry to evaluate subpopulations that exhibit decreased RBCs deformability upon an in vitro oxidation using 0.

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In contrast to electromagnetic fields, static magnetic fields (SMFs) have not been extensively studied in terms of their potential health consequences. Although upward- and downward-oriented magnetic poles may cause various biological effects, only the pole with the upward orientation has been mainly investigated. Considering that the interaction of antigen-presenting cells (APCs) and T lymphocytes is crucial to trigger an immune response, we assessed the effect of long-term exposure of human T lymphocytes and dendritic cells (DCs) to moderate strength SMFs of different orientations focusing on the cytokine profile of activated T cells.

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Integrating Newton's equations of motion in the reciprocal space.

J Chem Phys

August 2024

Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 16627 Prague, Czech Republic.

We here present the normal dynamics technique, which recasts the Newton's equations of motion in terms of phonon normal modes by exploiting a proper sampling of the reciprocal space. After introducing the theoretical background, we discuss how the reciprocal space sampling enables us to (i) obtain a computational speedup by selecting which and how many wave vectors of the Brillouin zone will be considered and (ii) account for distortions realized across large atomic distances without the use of large simulation cells. We implemented the approach into an open-source code, which we used to present three case studies: in the first one, we elucidate the general strategy for the sampling of the reciprocal space; in the second one, we illustrate the potential of the approach by studying the stabilization effect of temperature in α-uranium; and in the last one, we investigate the characterization of Raman spectra at different temperatures in MoS2/MX2 transition metal dichalcogenide heterostructures.

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Role of Trapped Molecules at Sliding Contacts in Lattice-Resolved Friction.

ACS Appl Mater Interfaces

August 2024

Scientific Computing Laboratory, Center for the Study of Complex Systems, Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, Belgrade 11080, Serbia.

Understanding atomic friction within a liquid environment is crucial for engineering friction mechanisms and characterizing surfaces. It has been suggested that the lattice resolution of friction force microscope in liquid environments stems from a dry contact state, with all liquid molecules expelled from the area of closest approach between the tip and substrate. Here, we revisit this assertion by performing in-depth friction force microscopy experiments and molecular dynamics simulations of the influence of surrounding water molecules on the dynamic behavior of the nanotribological contact between an amorphous SiO probe and a monolayer MoS substrate.

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Article Synopsis
  • Ground beetles have pygidial glands that produce secretions for defense against predators, and their structure and chemical makeup were studied in four species.
  • The morphological analysis was conducted for the first time using advanced microscopy techniques, capturing detailed measurements and images of the glands.
  • Gas chromatography-mass spectrometry revealed 30 compounds in the secretions, with unique findings such as 1-Undecanol and dodecyl butyrate, previously unreported in ground beetles.
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The selection of the appropriate biomonitor species is a crucial criterion for biomonitoring on a broad spatial scale. Mosses Hypnum cupressiforme and Brachythecium spp. and lichen Evernia prunastri were sampled at 22 remote sites over Serbia aiming interspecies comparison of their bioconcentration capacities.

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The paper presents a new algorithm for object alignment in digital holography with multiple spherical reference waves. The algorithm was applied to polarization sensing with two orthogonally polarized reference waves. A novel holographic setup was built using a diffraction grating to generate two symmetric reference waves, keeping the setup simple and highly adjustable.

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We report application of the knife-edge technique at the sharp edges of WS2 and MoS2 monolayer flakes for lateral and axial resolution assessment in all three modalities of nonlinear laser scanning microscopy: two-photon excited fluorescence (TPEF), second- and third-harmonic generation (SHG, THG) imaging. This technique provides a high signal-to-noise ratio, no photobleaching effect and shows good agreement with standard resolution measurement techniques. Furthermore, we assessed both the lateral resolution in TPEF imaging modality and the axial resolution in SHG and THG imaging modality directly via the full-width at half maximum parameter of the corresponding Gaussian distribution.

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Liver phospholipid fatty acid composition depends on the dietary lipid intake and the efficiency of hepatic enzymatic activity. Our study aimed to simultaneously investigate the liver phospholipid fatty acid composition in response to chronic linseed, palm, or sunflower oil diets. We used adult female C57/BL6 mice and randomly divided them into control and three groups treated with 25 % dietary oils.

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Velocity Map Imaging Photoelectron Spectroscopy of Silver Iodide Aerosol Particles.

Chemphyschem

September 2024

Center of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences - National Institute of Republic of Serbia, University of Belgrade, P.O. Box 522, 11001, Belgrade, Serbia.

The valence band electronic structure of isolated silver iodide nanoparticles (AgI NP) was investigated by vacuum-ultraviolet aerosol photoelectron spectroscopy using the velocity map imaging technique (VUV VMI-PES). The VUV VMI-PES results were obtained for polydisperse aerosol produced by aggregation of hydrocolloid of silver iodide particles 8-15 nm in size. The ionization energy of the AgI particles was found to be 6.

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Understanding the competing processes that govern far ultraviolet photodissociation (FUV-PD) of biopolymers such as proteins is a challenge. Here, we report a combined experimental and theoretical investigation of FUV-PD of protonated leucine-enkephalin pentapeptide ([YGGFL + H]) in the gas-phase. Time-dependent density functional theory (TD-DFT) calculations in combination with experiments and previous results for amino acids and shorter peptides help in rationalizing the evolution of the excited states.

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We consider a heterogeneous, globally coupled population of excitatory quadratic integrate-and-fire neurons with excitability adaptation due to a metabolic feedback associated with ketogenic diet, a form of therapy for epilepsy. Bifurcation analysis of a three-dimensional mean-field system derived in the framework of next-generation neural mass models allows us to explain the scenarios and suggest control strategies for the transitions between the neurophysiologically desired asynchronous states and the synchronous, seizure-like states featuring collective oscillations. We reveal two qualitatively different scenarios for the onset of synchrony.

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Breastfeeding provides numerous health benefits for both infants and mothers, promoting optimal growth and development while offering protection against various illnesses and diseases. This study investigated the levels of polychlorinated biphenyls (PCB), organochlorine pesticides (OCP) and polycyclic aromatic hydrocarbons (PAH) in human milk sampled in Zadar (Croatia). The primary objectives were twofold: firstly, to evaluate the individual impact of each compound on the total antioxidant capacity (TAC) value, and secondly, to assess associated health risks.

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Short-Term l-arginine Treatment Mitigates Early Damage of Dermal Collagen Induced by Diabetes.

Bioengineering (Basel)

April 2024

Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia.

Changes in the structural properties of the skin due to collagen alterations are an important factor in diabetic skin complications. Using a combination of photonic methods as an optic diagnostic tool, we investigated the structural alteration in rat dermal collagen I in diabetes, and after short-term l-arginine treatment. The multiplex approach shows that in the early phase of diabetes, collagen fibers are partially damaged, resulting in the heterogeneity of fibers, e.

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We present a numerical investigation of the influence of water content on the dynamic properties of a family of phosphonium-based room-temperature ionic liquids. The study presents a compelling correlation between structural changes in water-ionic liquid solutions and thermodynamic and transport properties across diverse systems. The results for phosphonium ionic liquids are compared with 1-butyl-3-methylimidazolium hexaphosphate ([bmim]PF) as a reference.

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