Publications by authors named "Artem Ivanov"

Immunotherapy has proven to be a boon for patients battling metastatic melanoma, significantly improving their clinical condition and overall quality of life. A compelling link between the composition of the gut microbiome and the efficacy of immunotherapy has been established in both animal models and human patients. However, the precise biological mechanisms by which gut microbes influence treatment outcomes remain poorly understood.

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A unique nanomaterial has been developed for sweat analysis, including glucose level monitoring. Simple resusable low-cost sensors from composite materials based on graphene, hexagonal boron nitride, and conductive PEDOT:PSS (poly(3,4-ethylenedioxythiophene)polystyrene sulfonate) polymer have been developed and fabricated 2D printing on flexible substrates. The sensors were tested as biosensors using different water-based solutions.

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Prospective composites, based on graphene (G) and hexagonal boron nitride (h-BN) nanoparticles, synthesized using a plasma jet and conducting polymer PEDOT:PSS, were used to create and study a set of sensors in the current study. The composites used were G:PEDOT:PSS (GPP) and G:h-BN:PEDOT:PSS (GBNPP). The PEDOT:PSS content in the composites was 10 wt%, and the ratio of G : h-BN was 1 : 1 in GBNPP.

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Article Synopsis
  • The study investigates the properties of vanadium oxide (VO) films created using plasma-enhanced atomic layer deposition for potential use in memristors on p-Si and fluorinated graphene substrates.
  • Samples of VO films were produced with varying thicknesses (1.0-10.0 nm), with surface analysis revealing initial island growth patterns and unique phase characteristics evident in Raman spectra for thicker films.
  • Memristive behavior was observed in films with thicknesses between 1.0-3.6 nm, showcasing a significant ON/OFF ratio, while thicker films (over 5.0 nm) showed reduced memristive switching abilities.
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A growing body of evidence links gut microbiota changes with inflammatory bowel disease (IBD), raising the potential benefit of exploiting metagenomics data for non-invasive IBD diagnostics. The sbv IMPROVER metagenomics diagnosis for inflammatory bowel disease challenge investigated computational metagenomics methods for discriminating IBD and nonIBD subjects. Participants in this challenge were given independent training and test metagenomics data from IBD and nonIBD subjects, which could be wither either raw read data (sub-challenge 1, SC1) or processed Taxonomy- and Function-based profiles (sub-challenge 2, SC2).

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The human gut microbiome plays an important role in both health and disease. Recent studies have demonstrated a strong influence of the gut microbiome composition on the efficacy of cancer immunotherapy. However, available studies have not yet succeeded in finding reliable and consistent metagenomic markers that are associated with the response to immunotherapy.

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During the pyrolysis of hydrocarbons in helium plasma jets in a plasma-chemical reactor, graphene flakes of a different structure and resistance were obtained. The presence of hydrogen in these structures was established by physicochemical methods, and its content depends on the pressure in the plasma-chemical reactor and the composition of a plasma-forming system. In addition to hydrogen, a relatively low concentration of oxygen atoms is present in the graphene flakes.

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  • NEC is a serious condition mostly affecting premature babies, influenced by gut bacteria imbalances and other factors, with term infants at risk due to heart-related issues.
  • A case involving a male neonate with CHD highlighted how surgery and persistent blood flow problems led to NEC episodes and notable changes in gut microbiome composition.
  • The findings suggest that both the gut microbiome and ongoing mesenteric hypoperfusion were significant factors in the development of NEC in the studied infant.
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  • The study explored the creation of 5G antennas using layers of graphene, which were printed with varying thicknesses on flexible materials like photographic paper.
  • Researchers examined how the thickness of graphene affects its sheet resistance to determine the optimal thickness needed for effective antenna performance.
  • The findings showed that using graphene allowed for the suppression of the first harmonic at 2.45 GHz while enabling radiation at the second harmonic of 5.75 GHz, indicating the potential to adjust antenna properties by altering the graphene layer thickness.
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The structure and electric properties of hexagonal boron nitride (h-BN):graphene composite with additives of the conductive polymer PEDOT:PSS and ethylene glycol were examined. The graphene and h-BN flakes synthesized in plasma with nanometer sizes were used for experiments. It was found that the addition of more than 10 mass% of PEDOT:PSS to the graphene suspension or h-BN:graphene composite in combination with ethylene glycol leads to a strong decrease (4-5 orders of magnitude, in our case) in the resistance of the films created from these suspensions.

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A new approach based on the irradiation by heavy high energy ions (Xe ions with 26 and 167 MeV) was used for the creation of graphene quantum dots in the fluorinated matrix and the formation of the memristors in double-layer structures consisting of fluorinated graphene (FG) on polyvinyl alcohol (PVA). As a result, memristive switchings with an ON/OFF current relation ~2-4 orders of magnitude were observed in 2D printed crossbar structures with the active layer consisting of dielectric FG films on PVA after ion irradiation. All used ion energies and fluences (3 × 10 and 3 × 10 cm) led to the appearance of memristive switchings.

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Gut microbiome in critically ill patients shows profound dysbiosis. The most vulnerable is the subgroup of chronically critically ill (CCI) patients - those suffering from long-term dependence on support systems in intensive care units. It is important to investigate their microbiome as a potential reservoir of opportunistic taxa causing co-infections and a morbidity factor.

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Article Synopsis
  • Memristors are promising components for neuromorphic electronics due to the unique properties of transition metal oxides, particularly vanadium oxide (VO).
  • Recent research focused on 2 to 10 nm VO nanoparticles encapsulated in fluorinated graphene (FG), demonstrating reliable bipolar resistive switching across 10 cycles with a notable ON/OFF current ratio.
  • The study highlights that the thickness of FG shells influences the switching voltage (2-4 V), while the encapsulation increases stability and prevents water loss, contributing to the development of bipolar nanoswitches.
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Fecal microbiota transplantation (FMT) is currently used in medicine to treat recurrent clostridial colitis and other intestinal diseases. However, neither the therapeutic mechanism of FMT nor the mechanism that allows the donor bacteria to colonize the intestine of the recipient has yet been clearly described. From a biological point of view, FMT can be considered a useful model for studying the ecology of host-associated microbial communities.

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Photoinduced intra- and interlayer electron transfer (ET) of doubly bridged donor-acceptor molecule, porphyrin-fullerene dyad (PF), was studied in single- and multi-layered Langmuir-Schäfer (LS) films and in LS films, where PF and an efficient electron donating polymer polyhexyltiophene (PHT) formed a bilayer PHT/PF and multi-layered PHT/PF structures. The ET through layers were investigated by a method, which measures the photovoltaic (PV) response proportional to the number of charge-separated (CS) states and to the CS distance between the electrons and holes formed in pulsed photo-excitation. Primary conclusions were, that ET starts as formations of CS dyads (PF) in single-layers, continues as long-range intra-layer charge migrations following interlayer CS between two adjacent monolayers.

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The possibility of graphene synthesis (the bottom-up approach) in plasma and the effective control of the morphology and electrical properties of graphene-based layers were demonstrated. Graphene flakes were grown in a plasma jet generated by a direct current plasma torch with helium and argon as the plasma-forming gases. In the case of argon plasma, the synthesized graphene flakes were relatively thick (2-6 nm) and non-conductive.

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BACKGROUND Pancreaticopleural fistula is a rare complication of chronic pancreatitis. Its formation is associated with local disruption of the pancreatic duct or pseudocyst communicating with the ductal system. Rarely, other intrathoracic complications may develop such as mediastinitis, pericarditis, hemothorax, and pleural empyema.

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A new approach to creating a new and locally nanostructured graphene-based material is reported. We studied the electric and structural properties of partially fluorinated graphene (FG) films obtained from an FG-suspension and nanostructured by high-energy Xe ions. Local shock heating in ion tracks is suggested to be the main force driving the changes.

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The resistivity of different films and structures containing fluorinated graphene (FG) flakes and chemical vapor deposition (CVD)-grown graphene of various fluorination degrees under tensile and compressive strains due to bending deformations was studied. Graphene and multilayer graphene films grown by means of the chemical vapor deposition (CVD) method were transferred onto the flexible substrate by laminating and were subjected to fluorination. They demonstrated a weak fluorination degree (F/C lower 20%).

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Two-layer films of partially fluorinated graphene (PFG) with graphene quantum dots and polyvinyl alcohol (PVA) were prepared by means of 2D printing technology. A stable resistive switching effect with the ON/OFF current ratio amounting from one to 4-5 orders of magnitude is found. The decrease in the PVA thickness leads to a change of the unipolar threshold switchings to the bipolar resistive switchings.

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