Publications by authors named "Elena Shevchenko"

In this study, we conducted a high-pressure investigation of CuSe nanostructures with pyramid- and plate-like morphologies, created through cation exchange from zinc-blende CdSe nanocrystals and wurtzite CdSe nanoplatelets respectively. Using a diamond anvil cell setup at the APS synchrotron, we observed the phase transitions in the CuSe nanostructures up to 40 GPa, identifying a novel CsCl-type lattice with 3̅ symmetry above 4 GPa. This CsCl-type structure, previously unreported in copper selenides, was partially retained after decompression.

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Article Synopsis
  • Researchers developed a highly porous TiO coating that exhibits self-cleaning properties and high water affinity, useful for applications like solar panels and mirrors.
  • The coating was created using a method called swelling-assisted sequential infiltration synthesis (SIS) combined with polymer removal, resulting in a smooth, interconnected pore structure.
  • Tests showed that the coating significantly improved its ability to repel water and effectively degraded about 92% of methylene blue dye when exposed to UV light for 180 minutes, indicating strong photocatalytic activity.
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The conformal nanoporous inorganic coatings with accessible pores that are stable under applied thermal and mechanical stresses represent an important class of materials used in the design of sensors, optical coatings, and biomedical systems. Here, we synthesize porous AlO and ZnO coatings by the sequential infiltration synthesis (SIS) of two types of polymers that enable the design of porous conformal coatings-polymers of intrinsic microporosity (PIM) and block co-polymer (BCP) templates. Using quartz crystal microbalance (QCM), we show that alumina precursors infiltrate both polymer templates four times more efficiently than zinc oxide precursors.

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Li-O batteries (LOB) performance degradation ultimately occurs through the accumulation of discharge products and irreversible clogging of the porous electrode during the cycling. Electrode binder degradation in the presence of reduced oxygen species can result in additional coating of the conductive surface, exacerbating capacity fading. Herein, a facile method to fabricate free-standing is established, binder-free electrodes for LOBs in which multi-wall carbon nanotubes form cross-linked networks exhibiting high porosity, conductivity, and flexibility.

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  • Researchers developed solid lubricant coatings using TiCT-Graphene Oxide blends, which were spray-coated on bearing steel surfaces to enhance performance in industrial applications.
  • Testing revealed these coatings significantly reduced friction to 0.065 at high pressures while also protecting against wear better than traditional single-component coatings.
  • The performance was linked to the creation of a robust tribolayer during operation, as shown through various advanced microscopy and spectroscopy techniques, emphasizing the connection between the material's structure, properties, and processing.
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The two-dimensional CsPbBr nanoplatelets have a quantum well electronic structure with a band gap tunable with sample thicknesses in discreet steps based upon the number of monolayers. The polarized optical properties of CsPbBr nanoplatelets are studied using fluorescence anisotropy and polarized transient absorption spectroscopies. Polarized spectroscopy shows that they have absorption and emission transitions which are strongly plane-polarized.

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Article Synopsis
  • Researchers are working towards achieving superlubricity, or nearly zero friction, by applying a blend of TiCT and MoS as a lubricant on rough steel surfaces.
  • Tests revealed that these nanocomposites could create superlubricious states, which had not previously been observed in either material alone under similar conditions.
  • Advanced techniques like Raman spectroscopy and electron microscopy helped identify a robust tribolayer that contributed to impressive lubrication performance at high pressure and sliding speeds.
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An introduction to the themed collection on CO capture and conversion, featuring exciting research on advanced nanoscale materials and reactions.

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Here, we introduce polymer of intrinsic microporosity 1 (PIM-1) to design single-layer and multilayered all-inorganic antireflective coatings (ARCs) with excellent mechanical properties. Using PIM-1 as a template in sequential infiltration synthesis (SIS), we can fabricate highly uniform, mechanically stable conformal coatings of AlO with porosities of ∼50% and a refractive index of 1.41 compared to 1.

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In this study, we update the evaluation of the Russian GPT3 model presented in our previous paper in predicting the length of stay (LOS) in neurosurgery. We aimed to assess the performance the Russian GPT-3 (ruGPT-3) language model in LOS prediction using narrative medical records in neurosurgery compared to doctors' and patients' expectations. Doctors appeared to have the most realistic LOS expectations (MAE = 2.

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Patients, relatives, doctors, and healthcare providers anticipate the evidence-based length of stay (LOS) prediction in neurosurgery. This study aimed to assess the quality of LOS prediction with the GPT3 language model upon the narrative medical records in neurosurgery comparing to doctors' and patients' expectations. We found no significant difference (p = 0.

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The construction of functional nano-/micro-architectures through self-assembly and self-organization of organic molecules and polymeric materials plays an important role in the development of many technologies. In this study, we report the spontaneous formation of uniform polymer microrods with lengths of up to a few tens of micrometers from paraffin wax. Through a solvent attrition approach, colloidal structures of paraffin wax are introduced into water.

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Here, we report a swelling-assisted sequential infiltration synthesis (SIS) approach for the design of highly porous zinc oxide (ZnO) films by infiltration of block copolymer templates such as polystyrene--polyvinyl pyridine with inorganic precursors followed by UV ozone-assisted removal of the polymer template. We show that porous ZnO coatings with the thickness in the range between 140 and 420 nm can be obtained using only five cycles of SIS. The pores in ZnO fabricated via swelling-assisted SIS are highly accessible, and up to 98% of pores are available for solvent penetration.

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Polymer templates play an essential role in the robust infiltration-based synthesis of functional multicomponent heterostructures with controlled structure, porosity, and composition. Such heterostructures are be used as hybrid organic-inorganic composites or as all-inorganic systems once the polymer templates are removed. Using iron oxide/alumina heterostructures formed by two-step infiltration of polystyrene-block-polyvinyl pyridine block copolymer with iron and aluminum precursors from the solution and vapor-phases, respectively, we show that the phase and morphology of iron oxide nanoparticles dramatically depend on the approach used to remove the polymer.

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We show that the self-assembly of monodisperse CdSe nanocrystals synthesized at lower temperature (∼310 °C) into three-dimensional supercrystals results in the formation of separate regions within the supercrystals that display photoluminescence at two distinctly different wavelengths. Specifically, the central portions of the supercrystals display photoluminescence and absorption in the orange region of the spectrum, around 585 nm, compared to the 575 nm photoluminescence maximum for the nanocrystals dispersed in toluene. Distinct domains on the surfaces and edges of the supercrystals, by contrast, display photoluminescence and absorption in the green region of the spectrum, around 570 nm.

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When nanoparticles (NPs) are assembled from solution, a common assembly method of choice is either solution destabilization or solvent evaporation technique. The destabilization of the NP solution by non-solvents results in the formation of faceted supercrystals (SCs) while periodic film-like assemblies are typically formed by solvent evaporation. Here, we reveal the effect of non-solvents in washing, dispersing, and crystallizing NPs.

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While a large number of studies deal with biomedical applications of various types of nanoparticles synthesized using wet chemistry, we propose the concept of targeted biosynthesis of nanoparticles in the living brain. Here we demonstrate that the pathological biochemical process of accumulation of reduced pyridine nucleotides under deleterious conditions of brain hypoxia can be redirected to drive the biosynthesis of biocompatible Au nanoparticles from a precursor salt in situ in the immediate vicinity of the hypoxia site, thereby restoring the redox status of the brain.

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Context: Physiological insights into blood flow alterations in cortical vessels after superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery are important for the prognosis of bypass sustainability and hemodynamic patency.

Aims: This study aims to assess the impact of STA-MCA bypass on local hemodynamics for patients with symptomatic carotid occlusions and Moyamoya disease.

Settings And Design: This article presents a prospective nonrandomized study of intraoperative blood flow measurements in cortical branches of MCA and donor vessel before and after cerebral revascularization.

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Article Synopsis
  • The study introduces a method for creating porous multicomponent structures using block-co-polymer templates, involving infiltration with inorganic materials and thermal processing.
  • This method produces materials like coatings and membranes with well-distributed metal or metal oxide nanoparticles, specifically highlighting catalytic PdO nanoparticles that resist high temperatures and enhance mass transport through their porous framework.
  • The versatility of this approach allows for the synthesis of various nanoparticles within the same porous support, showing promise for scalable and robust applications in catalysis.
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Precise engineering of nanoparticle superlattices (NPSLs) for energy applications requires a molecular-level understanding of the physical factors governing their morphology, periodicity, mechanics, and response to external stimuli. Such knowledge, particularly the impact of ligand dynamics on physical behavior of NPSLs, is still in its infancy. Here, we combine coarse-grained molecular dynamics simulations, and small angle X-ray scattering experiments in a diamond anvil cell to demonstrate that coverage density of capping ligands (i.

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Infiltration of the polymer templates with inorganic precursors using the selective vapor-phase infiltration approach, or sequential infiltration synthesis (SIS), allows the design of materials with advanced properties. Swelling of the block co-polymer (BCP) templates enables the additional control of the structure, porosity, and thickness of the composite or inorganic materials. Here, we use the highly precise quartz crystal microbalance (QCM) technique to investigate quantitatively the effect of the micelle opening by swelling and inorganic precursor infiltrating on the evolution of porosity in amphiphilic BCPs.

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Inorganic nanoporous materials with highly accessible pores are of great interest for the design of efficient catalytic, purification and detection systems. Limited access to the pores is a common problem associated with traditional approaches for the synthesis of porous materials, affecting the functionality of the low-density structure. Recently, infiltration of a nanoporous polymer template with inorganic precursors followed by oxidative annealing was proposed as a new and efficient approach to creating porous inorganic structures with controlled thickness, composition and pore sizes.

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Low-cost transition metal oxides are actively explored as alternative materials to precious metal-based electrocatalysts for the challenging multistep oxygen evolution reaction (OER). We utilized the Kirkendall effect allowing the formation of hollow polycrystalline, highly disordered nanoparticles (NPs) to synthesize highly active binary metal oxide OER electrocatalysts in alkali media. Two synthetic strategies were applied to achieve compositional control in binary transition metal oxide hollow NPs.

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