Gas sensors based on the multi-sensor platform MSP 632, with thin nanocomposite films based on tin dioxide with a low content of zinc oxide (0.5–5 mol.%), were synthesized using a solid-phase ...low-temperature pyrolysis technique. The resulting gas-sensitive ZnO-SnO2 films were comprehensively studied by atomic force microscopy, Kelvin probe force microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. The obtained films are up to 200 nm thick and consist of ZnO-SnO2 nanocomposites, with ZnO and SnO2 crystallite sizes of 4–30 nm. Measurements of ZnO-SnO2 films containing 0.5 mol.% ZnO showed the existence of large values of surface potential, up to 1800 mV, leading to the formation of a strong surface electric field with a strength of up to 2 × 107 V/cm. The presence of a strong surface electric field leads to the best gas-sensitive properties: the sensor’s responsivity is between two and nine times higher than that of sensors based on ZnO-SnO2 films of other compositions. A study of characteristics sensitive to NO2 (0.1–50 ppm) showed that gas sensors based on the ZnO-SnO2 film demonstrated a high sensitivity to NO2 with a concentration of 0.1 ppm at an operating temperature of 200 °C.
Heat capacity of dispersed rocks Galkin, A F; Yu Pankov, V
Journal of physics. Conference series,
12/2021, Letnik:
2131, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Abstract
Protection of automobile roads from negative cryogenic processes is a current issue to which significant attention is devoted in both scientific and engineering communities. In many cases ...important for practice, the the thermal factor determines the reliability and security of the use of the road in the cryolithic zone. The heat capacity of dispersed rocks is among the most important indicators of the physical properties determining the intensity of thermal processes in the road surfaces and road foundations. The precision of determination of the total heat capacity of the rocks in thawed and frozen state largely determines the precision of the forecast of the thermal regime of roads in the cryolithic zone. A complex assessment of the impact of ice content of the dispersed rocks on the value of total heat capacity was done. 2D and 3D charts which allow to assess the possible range of change in the heat capacity of the dispersed rocks in thawed and frozen state, in both a wide range and in the typical range of values, were produced. Among the main criteria determining the extent of the seasonal freezing and thawing of the soils of the active layer is the Stefan number, a dimensionless criterion. An overall assessment of the impact of ice content on the ground (rock) foundations of the roads and of the air temperature in the warm period of the year on the quantitative values of the Stefan number was done. Charts allowing to determine in both a wide and typical range the changes of values of the Stefan numbers, permitting to assess the possible range of changes of the Stefan number, were made. It was determined, in particular, that for the typical dispersed rocks of the road foundations in the cryolithic zone the range of change in the Stefan numbers is 2.1-6.5.
The evolutionary history of tumor cell populations can be reconstructed from patterns of genetic alterations. In contrast to stable genetic events, epigenetic states are reversible and sensitive to ...the microenvironment, prompting the question whether epigenetic information can similarly be used to discover tumor phylogeny. We examined the spatial and temporal dynamics of DNA methylation in a cohort of low-grade gliomas and their patient-matched recurrences. Genes transcriptionally upregulated through promoter hypomethylation during malignant progression to high-grade glioblastoma were enriched in cell cycle function, evolving in parallel with genetic alterations that deregulate the G1/S cell cycle checkpoint. Moreover, phyloepigenetic relationships robustly recapitulated phylogenetic patterns inferred from somatic mutations. These findings highlight widespread co-dependency of genetic and epigenetic events throughout brain tumor evolution.
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•Dramatic loss of DNA methylation during the progression of low-grade gliomas to GBM•Phenotypic convergence of genomic and epigenomic evolution on cell cycle defects•Phyloepigenetics recapitulates the phylogenetics of tumor evolution•Robust model of gliomagenesis from tumor initiation through malignant progression
Mazor et al. show that spatial and temporal patterns of DNA methylation and somatic mutations during the progression of low-grade gliomas to high-grade tumors produce remarkably similar evolutionary histories and both converge to deregulate the cell cycle.
An important feature of this research is the investigation of the de-alloyed catalysts based on the nanoparticles with a simple structure (alloy) and a complex structure (gradient). The resulting ...samples exhibit the 2–4 times higher mass activity in the ORR compared with the commercial Pt/C. The novelty of this study is due to the application of the express-electrochemical experiment to register the trend of changes in the ORR activity caused by rearranging the structure of bimetallic nanoparticles. The state-of-the-art protocol makes it possible to establish the dependence of properties of the de-alloyed catalysts on the nanoparticles’ structure obtained at the stage of the material’s synthesis. The study shows the possibility of determining the rate of the ongoing reorganization of bimetallic nanoparticles with different architectures. The PtCu/C electrocatalysts for proton-exchange membrane fuel cells presented in this work are commercially promising in terms of both the high functional characteristics and the production by facile one-pot methods.
Kisspeptin (KISS1) and its receptor (KISS1R) are important regulators of the reproductive function, along with gonadoliberin (GnRH), gonadotropins (luteinizing hormone (LH) and follicle-stimulating ...hormone (FSH)), and sex steroid hormones. Mutations of their genes alter sexual maturation. The p.P74S, p.H90D, and p.P110T missense mutations of
KISS1
are associated with central precocious puberty (CPP); and the p.G35S, p.C53R, and p.F117L mutations, with delayed puberty and isolated hypogonadotropic hypogonadism (IHH). The p.P196H and p.R386P mutations of
KISS1R
are also associated with CPP. However, a greater number of
KISS1R
mutations are associated with IHH, as is the case with p.L102P, p.L148S, p.E232Q, p.R297L, p.Y313H, pX399R, and more complex mutations, such as the 155-bp deletion that removes the acceptor splice site of intron 4 and part of exon 5, a deletion of the GCA triplet in position–2…–4 of intron 2, and an ACCGGCT insertion in the same site. The heterozygous compound mutations p.C223R/p.R297L and p.R331X/X399R and the 1-bp insertion 1001_1002insC of
KISS1R
are similarly associated with IHH. Leptin-dependent activation of
KISS1
in hypothalamic neurons was observed in mice and sheep, being especially evident after puberty. Leptin exerts a permissive effect in regulating fertility and facilitate the induction of puberty by hypothalamic KISS1 and GnRH and pituitary LH and FSH, which support the reproductive function during further life.
In this paper, we prove coercive a priori estimates of solutions of a Dirichlet-type boundary-value problem in a strip for a certain higher-order degenerate elliptic equation containing weighted ...derivatives of a special form up to the order 2
m
and ordinary partial derivatives up to the order 2
k−
1 under the condition 2
m >
2
k −
1. At the boundary of the strip, Dirichlet-type conditions are imposed. A coercive a priori estimate for solutions of the problem considered in special weighted Sobolev-type spaces is obtained.
Extra neutral gauge bosons, Z′s, are predicted by many theoretical scenarios of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future ...high energy colliders. It is quite possible that Z′s are heavy enough to lie beyond the discovery reach expected at the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z′ exchanges may occur at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We here discuss in this context the expected sensitivity to Z′ parameters of fermion-pair production cross sections at the planned International Linear Collider (ILC), especially as regards the potential of distinguishing different Z′ models once such deviations are observed. Specifically, we evaluate the discovery and identification reaches on Z′ gauge bosons pertinent to the E6, LR, ALR, and SSM classes of models at the ILC.
New heavy neutral gauge bosons
Z
′ are predicted by many models of physics beyond the Standard Model. It is quite possible that
Z
′s are heavy enough to lie beyond the discovery reach of the CERN ...Large Hadron Collider LHC, in which case only indirect signatures of
Z
′ exchanges may emerge at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We discuss in this context the foreseeable sensitivity to
Z
′s of
W
±
-pair production cross sections at the
e
+
e
−
International Linear Collider (ILC), especially as regards the potential of distinguishing observable effects of the
Z
′ from analogous ones due to competitor models with anomalous trilinear gauge couplings (AGC) that can lead to the same or similar new physics experimental signatures at the ILC. The sensitivity of the ILC for probing the
Z
–
Z
′ mixing and its capability to distinguish these two new physics scenarios is substantially enhanced when the polarization of the initial beams and the produced
W
±
bosons are considered. A model-independent analysis of the
Z
′ effects in the process
e
+
e
−
→
W
+
W
−
allows to differentiate the full class of vector
Z
′ models from those with anomalous trilinear gauge couplings, with one notable exception: the sequential SM (SSM)-like models can in this process not be distinguished from anomalous gauge couplings. Results of model-dependent analysis of a specific
Z
′ are expressed in terms of discovery and identification reaches on the
Z
–
Z
′ mixing angle and the
Z
′ mass.
The authors discuss feasibility of high-tonnage direct inclusion of overburden in composites for the construction of road layers at mines. It is found that overburden has a strength as per State ...Standard GOST 23558-94 and the prolonged dedusting effect. The optimal contents of the binder and fly ash are 8 and 10% by mass, respectively. Mechanical activation of fly ash for 1 min enlarges its specific surface by 2 times. The frost-resistant composites modified with mechanically activated fly ash and stabilizer (1% by mass) have the strength grades M20–M40.
Optical characteristics of germanium telluride (GeTe) thin films in multilayer structures are calculated. A model of a multilayer optical coating with a four-level transmission coefficient is ...developed. Based on the calculated data, thickness values are determined at which the transmittance change is greatest for 1550-nm modulated optical radiation. Experimental samples coated with antireflection GeTe films are synthesized and their optical transmission characteristics are investigated. Combinations of parameters of the multilayer structures for the implementation of contrast transmittance levels are determined. The results of the study represent the implementation of a multilevel artificial optical synapse for neuromorphic processors.
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