Here, the synthesis of holey carbonylated (C-ny) graphene derivative and its application for gas sensing is demonstrated. The carbonylation of graphene oxide leads to the 3-fold increase in the ...concentration of carbonyl groups’ up to 9 at.% with a substantial elimination of other oxygen functionalities. Such a chemical modification is accompanied by the perforation of the graphene layer with the appearance of matrices of nanoscale holes, leading to corrugation of the layer and its sectioning into localized domains of the π-conjugated network. Combined with the predominant presence of carbonyls, granting the specificity in gas molecules adsorption, these features result in the enhanced gas sensing properties of C-ny graphene at room temperature with a selective response to NH3. Opposite chemiresistive response towards ammonia when compared to other analytes, such as ethanol, acetone, CO2, is demonstrated for the C-ny graphene layer both in humid and dry air background. Moreover, a selective discrimination of all of the studied analytes is further approached by employing a vector signal generated by C-ny multielectrode chip. Comparing the experimental results with the calculations performed in framework of density functional theory, we clarify the effect of partial charge transfer caused by water and ammonia adsorption on the chemiresistive response.
Display omitted
•GO can be converted to the carbonylated graphene containing up to 9 at.% of carbonyls.•Carbonylation leads to holey and corrugated structure of graphene layer.•Holey-matrixed structure and carbonyls enhance graphene gas sensing properties.•Carbonylated graphene exhibits an exceptional selectivity regarding the NH3 detection.
The estimate of the change rate of the solar gravitational parameter d(
GM
⊙
)∕d
t
is obtained from processing modern positional observations of planets and spacecraft. Observations were processed ...and parameters were determined basing on the numerical planetary ephemeris EPM2019. The obtained annual decrease in solar mass
M
⊙
accounts for the loss through radiation
Ṁ
⊙rad
, through the outgoing solar wind
Ṁ
⊙wind
, and for the material falling on the Sun
Ṁ
⊙fall
. The estimated relative value is within −13.4×10
−14
< (
Ṁ
⊙
/
Ṁ
⊙
)
rad+wind+fall
< −8.7×10
−14
per year. The following range for the change rate of the gravitational constant
G
was obtained: −2.9 × 10
−14
<
Ġ
∕
G
< + 4.6 × 10
−14
per year (3
σ
). The new result reduces the interval for the change in
G
and narrows the limits of possible deviations for alternative gravitational theories from general relativity.
Specific features of using luminescent sensors with transducers based on a sensitive layer containing quantum dots immobilized in polymer matrixes of some fluorinated copolymers are described. ...Features of the formation of an analytical signal in time are studied. It is found that, in the analysis of some iodinated organic compounds, damped fluctuations of the luminescence intensity of the sensitive layer around a steady-state value can occur. Modern ideas of nonlinear and wave diffusion in polymer layers are attracted to explain the observed effects. Study of the kinetics of sorption by an independent method confirmed the fluctuations of sorption near its equilibrium value. The results obtained were used for the development of luminescent sensors based on quantum dots.
The feeding-related skull structures are described and occluding elements of the upper and lower regions of the buccopharyngeal cavity are analyzed in climbing perch. At each side of the ...neurocranium, the transverse process of the parasphenoid with four or five large conical teeth oppose the hypobranchial 3, and the medial teeth of the parasphenoid oppose the medial joints between paired hypobranchials 3 and ceratobranchials 4. As in the majority of other advanced Teleostei, the pharyngeal bite is carried out by the lower pharyngeal jaw (fused ceratobranchials 5) and upper pharyngeal jaws (left and right plates of pharyngobranchials 3–4). The latter jaws are articulated with paired pharyngeal processes of the basioccipital. At both sides of the skull, the strong elongated Baudelot’s ligament joins the basioccipital and supracleithrum. The hypothesis on the occurrence of the unique lower pharyngeal jaw–parasphenoid bite in climbing perch is rejected.
Display omitted
Vaterite particles are prospective biocompatible carriers for PDT.The proposed carriers are capable of cellular uptake.Encapsulation increases local PS concentration inside cells ...improving phototoxicity.Vaterite particles encourage reduction of PS therapeutic dose.
The elaboration of biocompatible and biodegradable carriers for photosensitizer targeted delivery is one of the most promising approaches in a modern photodynamic therapy (PDT). This approach is aimed at reducing sides effects connected with incidental toxicity in healthy tissue whilst also enhancing drug accumulation in the tumour area. In the present work, Photosens-loaded calcium carbonate (CaCO3) submicron particles in vaterite modification are proposed as a novel platform for anticancer PDT. Fast penetration of the carriers (0.9±0.2μm in diameter) containing 0.12% (w/w) of the photosensitizer into NIH3T3/EGFP cells is demonstrated. The captured particles provide the dye localization inside the cell increasing its local concentration, compared with ⿿free⿿ Photosens solution which is uniformly distributed throughout the cell. The effect of photosensitizer encapsulation into vaterite submicron particles on cell viability under laser irradiation (670nm, 19mW/cm2, 10min) is discussed in the work. As determined by a viability assay, the encapsulation renders Photosens more phototoxic. By this means, CaCO3 carriers allow improvement of the photosensitizer effectiveness supposing, therefore, the reduction of therapeutic dose. Summation of these effects with the simplicity, upscalability and cheapness of fabrication, biocompatibility and high payload ability of the vaterite particles hold out the prospect of a novel PDT platform.
—
The population structure and features of sexual maturity of gibel carp
Carassius gibelio
and crucian carp
C. carassius
are studied in a small (588 m
2
) natural pond. The abundance of the former ...species is 2.4 times larger than that of the latter species. The sex ratio (females : males) is 80 : 1 (
n
= 674) and 0.8 : 1 (
n
= 128), respectively. The gibel carp is represented by gynogenetic form. The populations of both species are characterized by similar age structure, reach sexual maturity at the age of 2–3 years, but the growth rate of the gibel carp is notably higher in comparison with that of the crucian carp; the latter species is represented by a small (on average, 55 mm
FL
) pedomorphic form. In the pond, individuals of both species inhabit mainly different ecological niches leading to a weak interspecific competition.
The morphology of asteriscus, lapillus, and (partly) sagitta is described in gibel and crucian carps from a small natural pond located in Nizhny Novgorod oblast, Russia. The otolith shape analysis ...was conducted to assess the interspecific differences. A comparison of otolith structure shows that the lapillus is more rounded in the latter species, and the asteriscus length (in anteroposterior direction) is larger than its width (in dorsoventral direction) in gibel carp vs. smaller than its width in crucian carp. Bilateral directional asymmetry is registered for some otolith measurements. The two species are significantly different by six shape indices of the asteriscus and lapillus. A distinct separation between three groups (mainly immature
C. gibelio
< 70 mm
FL
, mainly adult
C. gibelio
> 100 mm
FL
, and
C. carassius
37–86 mm
FL
) is observed based on Fourier and wavelet analyses of asteriscus and lapillus shapes. Otolith morphology can be used as an additional diagnostic character for the identification of
Carassius
species and possible hybrid individuals.
We give a constructive description of Hölder function classes on a compact subset of a chord-arc curve in ℝ
3
in terms of the rate of approximation by harmonic functions.
In this paper, the class of Hölder functions in the sense of the
L
p
norm on certain compacts in
(
m
3) is analyzed, and theorems of the approximation by functions being harmonic in the neighborhoods ...of these compacts are proved. These compacts represent a generalization of the concept of a chord-arc curve in
to higher dimensions. The neighborhood size decreases along with an increase in the approximation accuracy. Estimates of the approximation rate as well as the gradient of the approximation functions are made in the same
L
p
norm.
—
The mutual arrangement of the inner ear structures (membranous labyrinth) and their localization in the neurocranium are studied in gibel carp
Carassius gibelio
. The upper anterior part of the ...labyrinth (pars superior) is located at a substantial distance from its lower posterior part (pars inferior). The ventral region of the pars superior is freely located in the depression of the upper part of the prootic. The pars inferior including the sacculus and lagena is enclosed in a bone capsule of the basioccipital and bounded from above by a thin bony membrane (tectum basioccipital). The pars inferior structures that participated into the reception of vibrations of the swim bladder wall are located at the same level as the elements of the Weberian apparatus. The crus communis of the pars superior transits into the elongated ductus utriculus-sacculus, which enters the bony capsule through the medial opening in the tectum basioccipital. An updated scheme of the gibel carp inner ear is illustrated. The morphological and functional properties of the membranous labyrinth of the representatives of the group Otophysi are discussed.
PDF
