Enhanced Oxygen Mobility in Undoped ZrO2–CeO2 Heterostructure Petrov, Andrey V.; Ivanov-Schitz, Alexey K.; Murin, Igor V.
Physica status solidi. A, Applications and materials science,
January 2023, 20230101, Letnik:
220, Številka:
1
Journal Article
Recenzirano
The structural and ionic transport properties of the low‐index undoped ZrO2/CeO2 interfaces are simulated within the framework of density functional theory (DFT). These results show partial “melting” ...of the oxygen subsystem with significant disordering of the oxygen layers located between the layers of zirconium and cerium atoms. This leads to the existence of anomalously high ionic diffusion in simple undoped oxide phases with the fluorite structure.
The structural and ionic transport properties of the low‐index undoped ZrO2/CeO2 interfaces are simulated within the framework of density functional theory (DFT). The partial “melting” of the oxygen subsystem with significant disordering of the oxygen layers located between the layers of cubic zirconia and ceria leads to anomalously high ionic diffusion.
A 15‐year (2004–2018) record of mooring observations from the upper 50 m ocean in the eastern Eurasian Basin reveals increased current speeds and shear, associated with an increasing coupling between ...wind, ice, and oceanic currents and their vertical shear over 2004–2018, particularly in summer. Substantial increases in both current speeds and shears in the upper 50 m are dominated by a two times amplification of currents in the semidiurnal band, which includes tides and wind‐forced near‐inertial oscillations. For the first time the strengthened upper ocean currents and shear are observed to coincide with weakening stratification. This coupling links the Atlantic Water heat to the sea ice, a consequence of which would be reducing regional sea ice volume. These results point to a new positive feedback mechanism in which reduced sea ice extent facilitates more energetic inertial oscillations and associated upper‐ocean shear, thus leading in enhanced ventilation of the Atlantic water.
Plain Language Summary
Previous studies demonstrated that in recent years density gradients above the warm and salty intermediate (~150–900 m) water of Atlantic origin in the eastern Arctic Ocean have weakened, allowing stronger upward transport heat to the bottom of the sea ice. Using mooring observations, we show that this weakening of stratification has been accompanied by stronger upper‐ocean currents and their vertical shear and by increasing coupling between the wind and sea ice with upper ocean currents and shear. Most of this enhanced energy and shear is in the semidiurnal band, which includes baroclinic tides and wind‐driven inertial oscillations. The increased shear together with the weakening stratification indicate a greater potential for shear‐driven turbulent mixing. We propose a new process, the ice/ocean‐heat positive feedback, that can accelerate current sea ice loss and impede the rate of recovery of eastern Arctic sea ice even if large‐scale climate warming conditions relax.
Key Points
Currents and associated shear in the upper 50 m in the eastern Eurasian Basin are increased in the 2010s
Increased currents and shear are dominated by accelerating currents in the semidiurnal (inertial and tidal) band
There was an increasing coupling between wind, ice, and oceanic currents in the eastern Eurasian Basin over 2004–2018
The evidence is now overwhelming that partially assembled nucleosome states (PANS) are as important as the canonical nucleosome structure for the understanding of how accessibility to genomic DNA is ...regulated in cells. We use a combination of molecular dynamics simulation and atomic force microscopy to deliver, in atomic detail, structural models of three key PANS: the hexasome (H2A·H2B)·(H3·H4)2, the tetrasome (H3·H4)2, and the disome (H3·H4). Despite fluctuations of the conformation of the free DNA in these structures, regions of protected DNA in close contact with the histone core remain stable, thus establishing the basis for the understanding of the role of PANS in DNA accessibility regulation. On average, the length of protected DNA in each structure is roughly 18 basepairs per histone protein. Atomistically detailed PANS are used to explain experimental observations; specifically, we discuss interpretation of atomic force microscopy, Förster resonance energy transfer, and small-angle x-ray scattering data obtained under conditions when PANS are expected to exist. Further, we suggest an alternative interpretation of a recent genome-wide study of DNA protection in active chromatin of fruit fly, leading to a conclusion that the three PANS are present in actively transcribing regions in a substantial amount. The presence of PANS may not only be a consequence, but also a prerequisite for fast transcription in vivo.
Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells ...and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50 °C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1-5 W/cm(2)). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy.
Over the past decades, the problem of bacterial resistance to most antibiotics has become a serious threat to patients’ survival. Nevertheless, antibiotics of a novel class have not been approved ...since the 1980s. The development of antibiotic potentiators is an appealing alternative to the challenging process of searching for new antimicrobials. Production of H2S—one of the leading defense mechanisms crucial for bacterial survival—can be influenced by the inhibition of relevant enzymes: bacterial cystathionine γ-lyase (bCSE), bacterial cystathionine β-synthase (bCBS), or 3-mercaptopyruvate sulfurtransferase (MST). The first one makes the main contribution to H2S generation. Herein, we present data on the synthesis, in silico analyses, and enzymatic and microbiological assays of novel bCSE inhibitors. Combined molecular docking and molecular dynamics analyses revealed a novel binding mode of these ligands to bCSE. Lead compound 2a manifested strong potentiating activity when applied in combination with some commonly used antibiotics against multidrug-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus. The compound was found to have favorable in vitro absorption, distribution, metabolism, excretion, and toxicity parameters. The high effectiveness and safety of compound 2a makes it a promising candidate for enhancing the activity of antibiotics against high-priority pathogens.
An efficient method for the synthesis of pharmaceutically prospective pyrrole-aminopyrimidine ensembles (in up to 91% yield) by the cyclocondensation of easily available acylethynylpyrroles with ...guanidine nitrate has been developed. The reaction proceeds under heating (110-115 °C, 4 h) in the KOH/DMSO system. In the case of 2-benzoylethynylpyrrole, the unexpected addition of the formed pyrrole-aminopyrimidine as N- (NH moiety of the pyrrole ring) and C- (CH of aminopyrimidine) nucleophiles to the triple bond is observed.
This article shows that two extremely important families of fused heterocyclic assemblies, namely 6-methylbenzo4,5imidazo1,2-
pyrrolo2,1-
pyrazine and 5a-methyl-5a,6-dihydro-5
,12
...-benzo4,5imidazo1,2-
pyrrolo1,2-
pyrazine, can be synthesized from only two available building blocks (
-allenylpyrrole-2-carbaldehyde and
-phenylenediamine) by controlling only one reaction parameter (water content of the medium). It should be emphasized that the latter class of compounds (with an
arrangement) is previously unknown. If the allene group is introduced not into the starting compound, but during the reaction (in superbase media), a heterocyclic ensemble, 5-methylbenzo4,5imidazo1,2-
pyrrolo2,1-
pyrazines, with a different position of the methyl group is formed.
This work demonstrates the use of a modified mica to concentrate proteins, which is required for proteomic profiling of blood plasma by mass spectrometry (MS). The surface of mica substrates, which ...are routinely used in atomic force microscopy (AFM), was modified with a photocrosslinker to allow "irreversible" binding of proteins via covalent bond formation. This modified substrate was called the AFM chip. This study aimed to determine the role of the surface and crosslinker in the efficient concentration of various types of proteins in plasma over a wide concentration range. The substrate surface was modified with a 4-benzoylbenzoic acid N-succinimidyl ester (SuccBB) photocrosslinker, activated by UV irradiation. AFM chips were incubated with plasma samples from a healthy volunteer at various dilution ratios (10
X, 10
X, and 10
X). Control experiments were performed without UV irradiation to evaluate the contribution of physical protein adsorption to the concentration efficiency. AFM imaging confirmed the presence of protein layers on the chip surface after incubation with the samples. MS analysis of different samples indicated that the proteomic profile of the AFM-visualized layers contained common and unique proteins. In the working series of experiments, 228 proteins were identified on the chip surface for all samples, and 21 proteins were not identified in the control series. In the control series, a total of 220 proteins were identified on the chip surface, seven of which were not found in the working series. In plasma samples at various dilution ratios, a total of 146 proteins were identified without the concentration step, while 17 proteins were not detected in the series using AFM chips. The introduction of a concentration step using AFM chips allowed us to identify more proteins than in plasma samples without this step. We found that AFM chips with a modified surface facilitate the efficient concentration of proteins owing to the adsorption factor and the formation of covalent bonds between the proteins and the chip surface. The results of our study can be applied in the development of highly sensitive analytical systems for determining the complete composition of the plasma proteome.
Abstract
Progress in RNA metabolism and function studies relies largely on molecular imaging systems, including those comprising a fluorogenic dye and an aptamer-based fluorescence-activating tag. G4 ...aptamers of the Mango family, typically combined with a duplex/hairpin scaffold, activate the fluorescence of a green light-emitting dye TO1-biotin and hold great promise for intracellular RNA tracking. Here, we report a new Mango-based imaging platform. Its key advantages are the tunability of spectral properties and applicability for visualization of small RNA molecules that require minimal tag size. The former advantage is due to an expanded (green-to-red-emitting) palette of TO1-inspired fluorogenic dyes, and the truncated duplex scaffold ensures the latter. To illustrate the applicability of the improved platform, we tagged Mycobacterium tuberculosis sncRNA with the shortened aptamer-scaffold tag. Then, we visualized it in bacteria and bacteria-infected macrophages using the new red light-emitting Mango-activated dye.
Graphical Abstract
Graphical Abstract
Tag-activated fluorogenic dyes with tunable spectral properties were obtained by a new synthetic approach. A very short aptamer-based tag for labeling short RNA was constructed. The developed fluorogenic dye-tag system was used to visualize target RNA in bacteria internalized by macrophages.
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► A highly sensitive immunoassay for detection of cardiac myoglobin was designed. ► A gold nanoparticles were used for SPR signal amplification. ► The limit of detection of cMb in a ...serum sample was found to be as low as 10pM.
A highly sensitive reverse sandwich immunoassay for the detection of human cardiac myoglobin (cMb) in serum was designed utilizing a gold nanoparticle (AuNP)-enhanced surface plasmon resonance (SPR) biosensor. First, a monoclonal anti-cMb antibody (Mab1) was covalently immobilized on the sensor surface. AuNPs were covalently conjugated to the second monoclonal anti-cMb antibody (Mab2) to form an immuno-gold reagent (Mab2-AuNP). The reverse sandwich immunoassay consists of two steps: (1) mixing the serum sample with Mab2-AuNP and incubation for the formation of cMb/Mab2-AuNP complexes and (2) sample injection over the sensor surface and evaluation of the Mab1/cMb/Mab2-AuNP complex formation, with the subsequent calculation of the cMb concentration in the serum. The biosensor signal was amplified approximately 30-fold compared with the direct reaction of cMb with Mab1 on the sensor surface. The limit of detection of cMb in a human blood serum sample was found to be as low as 10pM (approx. 0.18ngmL−1), and the inter-assay coefficient of variation was less than 3%. Thus, the developed SPR-based reverse sandwich immunoassay has a sensitivity that is sufficient to measure cMb across a wide range of normal and pathological concentrations, allowing an adequate estimation of the disease severity and the monitoring of treatment.
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