39 results match your criteria: "Institute of Physical Chemistry "Rostislaw Kaischew"[Affiliation]"
Materials (Basel)
November 2024
Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia, Bulgaria.
In this work, atmospheric pulsed laser deposition was used to prepare photosensitive elements. This technology is a practical and relatively inexpensive way of obtaining highly porous nanostructures composed of nanoparticles or nanoaggregates characterized by a large surface-to-volume ratio. Samples were produced via laser nanosecond or picosecond laser ablation of pure ZnO or mixed ZnO-TiO targets on quartz substrates with pre-deposited gold electrodes.
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August 2024
School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
A surfactant's equilibrium spreading pressure (ESP) is the maximum decrease in surface tension achievable at equilibrium below the Krafft point. Difficulties in measuring the ESP have been noted previously but no well-established experimental protocols to overcome them exist. We present a case study of three solid amphiphiles with different propensities to spread on the air-water interface.
View Article and Find Full Text PDFLangmuir
August 2024
Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
The article summarizes the results of our research on the behavior of ions at uncharged fluid interfaces, with a focus on moderately to highly concentrated aqueous electrolytes. The ion-specific properties of such interfaces have been analyzed. The ion-specificity series are different for water|air and water|oil; different for surface tension , surface Δ potential and electrolyte adsorption, and they change with concentration.
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May 2024
Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Preparing high-performance oxygen evolution reaction (OER) catalysts with low precious metal loadings for water electrolysis applications (e.g., for green hydrogen production) is challenging and requires electrically conductive, high-surface-area, and stable support materials.
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March 2024
School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
Amphiphilic fluorocarbon substances are a trending topic of research due to their wide range of applications accompanied by an alarming environmental and health impact. In order to predict their fate in the environment, use them more economically, develop new water treatment methods, etc., a better understanding of their physicochemical behavior is required.
View Article and Find Full Text PDFInt J Mol Sci
November 2023
Division of Systems Medicine, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, UK.
Currently, X-ray crystallography, which typically uses synchrotron sources, remains the dominant method for structural determination of proteins and other biomolecules. However, small protein crystals do not provide sufficiently high-resolution diffraction patterns and suffer radiation damage; therefore, conventional X-ray crystallography needs larger protein crystals. The burgeoning method of serial crystallography using X-ray free-electron lasers (XFELs) avoids these challenges: it affords excellent structural data from weakly diffracting objects, including tiny crystals.
View Article and Find Full Text PDFMaterials (Basel)
November 2023
Institute of Optical Materials and Technologies "Acad. Jordan Malinowski", Bulgarian Academy of Sciences, "Acad. G. Bonchev" Str., bl. 109, 1113 Sofia, Bulgaria.
BaMoO was obtained via facile mechanochemical synthesis at room temperature and a solid-state reaction. An evaluation of the phase composition and structural and optical properties of BaMoO was conducted. The influence of different milling speeds on the preparation of BaMoO was explored.
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October 2023
Laboratory on Structure and Properties of Polymers, Faculty of Chemistry and Pharmacy, University of Sofia, 1, James Bourchier Blvd., 1164 Sofia, Bulgaria.
Biomacromolecules control mineral formation during the biomineralization process, but the effects of the organic components' functionality on the type of mineral phase is still unclear. The biomimetic precipitation of calcium phosphates in a physiological medium containing either polycarboxybetaine (PCB) or polysulfobetaine (PSB) was investigated in this study. Amorphous calcium phosphate (ACP) or a mixture of octacalcium phosphate (OCP) and dicalcium phosphate dihydrate (DCPD) in different ratios were identified depending on the sequence of initial solution mixing and on the type of the negative functional group of the polymer used.
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September 2023
"Rostislaw Kaischew" Institute of Physical Chemistry, Bulgarian Academy of Sciences, "Acad. G. Bonchev" Street, bl. 11, 1113 Sofia, Bulgaria.
The corrosion-protective influence of eco-friendly ceria conversion coatings deposited on Al-1050 alloy, additionally treated in mixed NaHPO and Ca(NO) solution, was studied. The main aim of this work was to investigate how the obtained mixed systems of coatings eliminates the negative role of cracks and pores on the surface formed after deposition only of ceria coating. For this purpose, the growth structure, main components and corrosion resistance of the so formed protective systems were investigated by SEM, EDS, XRD, XPS and electrochemical (PDP, Rp, etc.
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September 2023
Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia, Bulgaria.
In this study, we present a physical method for the fabrication of oriented nanowires composed of mixed metal oxides. Pulsed laser deposition carried out in the air under atmospheric pressure was used for the production of samples. Two sets of experiments were performed by applying nanosecond and picosecond laser ablation, respectively.
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September 2023
Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia, Bulgaria.
In this work, we present the fabrication of thin films/nanostructures of metals and metal oxides using picosecond laser ablation. Two sets of experiments were performed: the depositions were carried out in vacuum and in air at atmospheric pressure. The subjects of investigation were the noble metals Au and Pt and the metal oxides ZnO and TiO.
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September 2023
Institute of Physical Chemistry 'Acad. Rostislaw. Kaischew', 1113 Sofia, Bulgaria.
Negatively charged carbon dots (Cdots) were successfully impregnated into chitosan/alginate film formed on model colloidal particles as a result of the attractive interactions with the chitosan molecules. The electrical properties of the produced films were studied by electrokinetic spectroscopy. In this study, the electric light scattering method was applied for first the time for the investigation of suspensions of carbon-based structures.
View Article and Find Full Text PDFJ Phys Chem Lett
May 2023
Queen Mary University of London, School of Engineering and Materials Science, Mile End Road, London E1 4NS, United Kingdom.
The interactions between ions and lipid monolayers have captivated the attention of biologists and chemists alike for almost a century. In the absence of experimentally accessible concentration profiles, the electrolyte adsorption remains the most informative quantitative characteristic of the ion-lipid interactions. However, there is no established procedure to obtain the electrolyte adsorption on spread lipid monolayers.
View Article and Find Full Text PDFInt J Mol Sci
September 2022
Section of Biomolecular Medicine, Division of Systems Medicine, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, UK.
Well-diffracting protein crystals are indispensable for X-ray diffraction analysis, which is still the most powerful method for structure-function studies of biomolecules. A promising approach to growing such crystals is the use of porous nucleation-inducing materials. However, while protein crystal nucleation in pores has been thoroughly considered, little attention has been paid to the subsequent growth of crystals.
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February 2022
School of Engineering-PPGEMN, Mackenzie Presbyterian University, Rua da Consolação, 930, São Paulo 01302-907, SP, Brazil.
Hexagonal boron-nitride nanoparticle coating was deposited on AISI 1045 steel surface. The deposition process included a transformation of B-containing thin organic film into nanocrystalline BN using two methods: thermal annealing at 450-850 °C and reactive ion etching in Ar/N plasma. The film structure, phases, and film morphology of deposited nanoparticles of boron nitride on AISI 1045 steel were characterized by XPS, XRD, and EDS.
View Article and Find Full Text PDFIUCrJ
March 2021
Division of Systems Medicine, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom.
The nucleation ability of pores is explained using the equilibration between the cohesive energy maintaining the integrity of a crystalline cluster and the destructive energy tending to tear it up. It is shown that to get 3D crystals it is vital to have 2D crystals nucleating in the pores first. By filling the pore orifice, the 2D crystal nuclei are more stable because their peripheries are protected from the destructive action of water molecules.
View Article and Find Full Text PDFBiophys Chem
March 2021
Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
Elucidating electrokinetic stability by which surface charges regulate toxins interaction with erythrocytes is crucial for understanding the cell functionality. Electrokinetic properties of human erythrocytes upon treatment of Vipoxin, phospholipase A (PLA) and Vipoxin acidic component (VAC), isolated from Vipera ammodytes meridionalis venom were studied using particle microelectrophoresis. PLA and Vipoxin treatments alter the osmotic fragility of erythrocyte membranes.
View Article and Find Full Text PDFJ Biol Phys
December 2020
Institute of Physical Chemistry "Rostislaw Kaischew", Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 11, 1113, Sofia, Bulgaria.
Here we provide an analysis of primary results obtained from a study of apoferritin crystal nucleation in compositionally invariant bulk solution at constant supersaturation ratio of the protein. The temperature dependence of the stationary crystal nucleation rate in the protein bulk solution is obtained with the help of experimentally determined probability for detection of at least one crystal per solution volume until a given time. The stationary crystal nucleation rate demonstrates unusual behavior with temperature.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2019
Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine , Imperial College London, London SW7 2AZ , U.K.
Macromolecular crystallization is crucial to a large number of scientific fields, including structural biology; drug design, formulation, and delivery; manufacture of biomaterials; and preparation of foodstuffs. The purpose of this study is to facilitate control of crystallization, by investigating hydrophobic interface-assisted protein crystallization both theoretically and experimentally. The application of hydrophobic liquids as nucleation promoters or suppressors has rarely been investigated, and provides an underused avenue to explore in protein crystallization.
View Article and Find Full Text PDFRSC Adv
January 2019
Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences Sofia 1113 Bulgaria
The electrocatalytic production of hydrogen from methanol dehydrogenation successfully uses platinum catalysts. However, they are expensive and Pt has the tendency to be poisoned from the intermediate compounds, formed during the methanol oxidation reaction (MOR). For these two reasons, there has been active research for alternative bi- and tri-component Pt-based catalysts.
View Article and Find Full Text PDFJ Mol Model
February 2018
Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria.
Abiogenic aluminum has been implicated in some health disorders in humans. Protein binding sites containing essential metals (mostly magnesium) have been detected as targets for the "alien" Al. However, the acute toxicity of aluminum is very low.
View Article and Find Full Text PDFBeilstein J Nanotechnol
November 2017
Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Sofia 1784, Bulgaria.
We present a fast and flexible method for the fabrication of Au nanocolumns. Au nanostructures were produced by pulsed laser deposition in air at atmospheric pressure. No impurities or Au compounds were detected in the resulting samples.
View Article and Find Full Text PDFJ Mol Model
February 2017
Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria.
The effect of the extra methylene group on the ligation properties of glutamic (Glu) vs. aspartic (Asp) acid, and glutamine (Gln) vs. asparagine (Asn) amino acids-two pairs of protein building blocks differing by the length of their side chains-has been studied by employing DFT calculations combined with polarizable continuum model (PCM) computations.
View Article and Find Full Text PDFSci Rep
January 2017
Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
The most powerful method for protein structure determination is X-ray crystallography which relies on the availability of high quality crystals. Obtaining protein crystals is a major bottleneck, and inducing their nucleation is of crucial importance in this field. An effective method to form crystals is to introduce nucleation-inducing heterologous materials into the crystallization solution.
View Article and Find Full Text PDFJ Biol Phys
September 2015
Department of Phase Formation, Crystalline and Amorphous Materials, Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 11, Sofia, 1113, Bulgaria,
Nucleation of lysozyme crystals in quiescent solutions at a regime of progressive nucleation is investigated under an optical microscope at conditions of constant supersaturation. A method based on the stochastic nature of crystal nucleation and using discrete time sampling of small solution volumes for the presence or absence of detectable crystals is developed. It allows probabilities for crystal detection to be experimentally estimated.
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