Density Functional Theory based studies about the inhibition of corrosion affecting the cathode hematite surface by coverage with an methylimidazole-based ionic liquid, IL, were performed. Inhibition ...performance is tuned through the length of aliphatic chains C n attached to the imidazolium aromatic ring, where n = 1, ..., 20. Frontier molecular orbitals and energy gaps for single ILs and a pristine (11̅2) hematite surface, the energy difference between ILs and hematite-surface, Fukui indices for the ILs, and adsorption energies and charge transfers for ILs/hematite surface systems were calculated. Results show that adsorption activity is due to the donation/back-donation bonding among the imidazolium aromatic ring of the ILs and the exposed iron atoms of the hematite surface. Dispersive long-range interactions from the ILs alkyl tails allow a closer bonding of the corrosion inhibitor molecules to the hematite surface; the charge transfer between the IL and the hematite is in C18. The optimal alkyl chain size is 18 and this is in full agreement with the reported experimental alkyl chain size that produces high inhibitory properties of related vinylimidazolium ILs.
ABSTRACT
We present an analysis of the evolution of circumstellar dust and molecules in the environment of the very late thermal pulse object V4334 Sgr (Sakurai’s object) over an ∼20-yr period, ...drawing on ground-, airborne-, and space-based infrared photometry and spectroscopy. The dust emission, which started in 1997, resembles a blackbody that cooled from ∼1200 K in 1998 August to ∼180 K in 2016 July. The dust mass, assuming amorphous carbon, was ∼5 × 10−10 M⊙ in 1998 August, and we estimate that the total dust mass was ∼2 × 10−5 M⊙ by ∼2016. The appearance of a near-infrared excess in 2008 suggests that a new episode of (or renewed) mass-loss began then. We infer lower limits on the bolometric luminosity of the embedded star from that of the dust shell, which rose to ∼16 000 L⊙ before declining to ∼3000 L⊙. There is evidence for weak 6–7 μm absorption, which we attribute to hydrogenated amorphous carbon formed in material ejected by Sakurai’s object during a mass ejection phase that preceded the 1997 event. We detect small hydrocarbon and other molecules in the spectra, and trace the column densities in hydrogen cyanide (HCN) and acetylene (C2H2). We use the former to determine the 12C/13C ratio to be 6.4 ± 0.7, 14 times smaller than the Solar system value.
We have observed the massive protostar AFGL 2136 IRS 1 in multiple wavelength windows in the near- to mid-infrared at high (∼3 km s−1) spectral resolution using VLT+CRIRES, SOFIA+EXES, and Gemini ...North+TEXES. There is an abundance of H2O absorption lines from the ν 1 and ν 3 vibrational bands at 2.7 μm, from the ν 2 vibrational band at 6.1 μm, and from pure rotational transitions near 10–13 μm. Analysis of state-specific column densities derived from the resolved absorption features reveals that an isothermal absorbing slab model is incapable of explaining the relative depths of different absorption features. In particular, the strongest absorption features are much weaker than expected, indicating optical depth effects resulting from the absorbing gas being well mixed with the warm dust that serves as the “background” continuum source at all observed wavelengths. The velocity at which the strongest H2O absorption occurs coincides with the velocity centroid along the minor axis of the compact disk in Keplerian rotation recently observed in H2O emission with ALMA. We postulate that the warm regions of this dust disk dominate the continuum emission at near- to mid-infrared wavelengths, and that H2O and several other molecules observed in absorption are probing this disk. Absorption line profiles are not symmetric, possibly indicating that the warm dust in the disk that produces the infrared continuum has a nonuniform distribution similar to the substructure observed in 1.3 mm continuum emission.
We report on the detection of hot CO
in the O-rich AGB star R Leo based on high spectral resolution observations in the range 12.8 - 14.3
m carried out with the Echelon-cross-Echelle Spectrograph ...(EXES) mounted on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We have found ≃ 240 CO
emission lines in several vibrational bands. These detections were possible thanks to a favorable Doppler shift that allowed us to avoid contamination by telluric CO
features. The highest excitation lines involve levels at an energy of ≃ 7000 K. The detected lines are narrow (average deconvolved width ≃ 2.5 km s
) and weak (usually ≲ 10% the continuum). A ro-vibrational diagram shows that there are three different populations, warm, hot, and very hot, with rotational temperatures of ≃ 550, 1150, and 1600 K, respectively. From this diagram, we derive a lower limit for the column density of ≃ 2.2 × 10
cm
. Further calculations based on a model of the R Leo envelope suggest that the total column density can be as large as 7 × 10
cm
and the abundance with respect to H
- 2.5 × 10
. The detected lines are probably formed due to de-excitation of CO
molecules from high energy vibrational states, which are essentially populated by the strong R Leo continuum at 2.7 and 4.2
m.
The presence of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) was analysed in air particulate matter ≤ 2.5 μm (PM2.5) and ≤10 μm (PM10) collected in the Metropolitan ...Zone of Mexico Valley (MZMV), during 2013 and 2014, respectively. Spatial and seasonal distributions of PM and their organic content named solvent extracted organic matter (SEOM) were determined. PM mass concentration and SEOM/PM ratios were compared with previous studies in 2006 in Mexico City. PM2.5 concentration was like found in 2006, however, PM10 decreased ∼43%. The SEOM/PM10 ratio was kept constant, suggesting a decrease in SEOM as well as PM10 emitted from natural sources, probably as a result of changes in the land use due to urban growth. A decrease ∼50% SEOM/PM2.5 ratio was observed in the same period, linked to adequate strategies and public policies applied by the local and federal governments to control the organic matter emitted from anthropogenic sources.
Seven out of sixteen OCPs and five out of six PBDEs were found. The most common POPs were endosulfan I, endosulfan II, endosulfan sulfate, BDE-47 and BDE-99, present on >90% of the sampling days. OCPs in PM2.5 and PBDEs in PM10 showed seasonal variability. Higher PBDEs concentration in both particle sizes were observed at east and southeast of the MZMV, where one of the biggest landfills and wastewater treatment plants are located. OCPs in PM10 were mainly emitted from agricultural areas located to the southwest, southeast and east of the MZMV. OCPs in PM2.5 showed a regional contribution from the north and introduced into the valley. OCP degradation products were dominant over native OCPs, indicating no fresh OCP use. POPs comparison with other cities was made. Agreements and commissions created by the Mexican government reduced OCPs emissions, however, more effort must be made to control PBDE emission sources.
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•OCPs and PBDEs were analysed in the organic matter of PM2.5 and PM10 in Mexico Valley.•Adequate strategies and programs have been applied by the Governments to reduce the use of OCPs, as well as the organic matter emitted by combustion sources by Adequate public policies reduced the use of OCPs, as well as the organic matter emitted by combustion sources.•Endosulfan I, endosulfan II, endosulfan sulfate, BDE-47 and BDE-99, were present in >90% of the sampling days.•PBDEs were mainly emitted by landfill and WWTP, while OCPs by agricultural areas and regional contribution.•OCPs degradation products were dominant over native OCPs, indicating no fresh OCPs use.
PBDEs and OCPs in PM2.5 and PM10 in an urban area. Adequate public policies to increase air quality related to unregulated organic air pollutants.
Footwear comfort is one of the determinant factors in a buyout decision. The understanding of which brain patterns are involved in the comfort perception of footwear could be an important element to ...develop the consumer neuroscience field, and could even help during the development phase of new products. The present paper studies the comfort perception through the electroencephalography analysis of the brain signals of ten subjects during walking. For the analysis, different features were extracted from the subject's biosignals based on power spectral density attributes and temporal and statistical parameters of the data under analysis. The research compared the features when the subjects were wearing a comfortable and a uncomfortable shoe by size on a treadmill. The results indicate that both kind of shoes could be classified with average accuracies of 84,3% and that an influence of parietal, tempo-parietal and in a minor way frontal lobes was detected. Despite the subject's dependency on the results, the research demonstrates that a common electrode and feature configuration could be applied keeping the results in an average accuracy of 83,7% and that a reduction to a 12 electrode setup maintains the accuracy at a 78,0% value.
The satellitome of the beetle
Linneo, 1758 has been characterized through chromosomal analysis, genomic sequencing, and bioinformatics tools. C-banding reveals the presence of constitutive ...heterochromatin blocks enriched in A+T content, primarily located in pericentromeric regions. Furthermore, a comprehensive satellitome analysis unveils the extensive diversity of satellite DNA families within the genome of
. Using fluorescence in situ hybridization techniques and the innovative CHRISMAPP approach, we precisely map the localization of satDNA families on assembled chromosomes, providing insights into their organization and distribution patterns. Among the 165 identified satDNA families, only three of them exhibit a remarkable amplification and accumulation, forming large blocks predominantly in pericentromeric regions. In contrast, the remaining, less abundant satDNA families are dispersed throughout euchromatic regions, challenging the traditional association of satDNA with heterochromatin. Overall, our findings underscore the complexity of repetitive DNA elements in the genome of
and emphasize the need for further exploration to elucidate their functional significance and evolutionary implications.
Abstract
In this paper, we experimentally demonstrate generation of diverse structures of robust optical pulses obtained with a ring cavity passively mode-locked fiber laser based on a double-clad ...erbium-ytterbium doped fiber, and operating at net-anomalous cavity dispersion. A half-wave and a quarter-wave retarder plates allow adjustable saturable absorbing action by the nonlinear polarization rotation technique. Pulsed laser operation in quasi- continuous wave, molecules of solitons, and single-wavelength noise-like pulses (NLPs) regimes is obtained by properly adjusting the wave retarders. In the soliton and NLPs operating regimes, the central laser wavelength lies in the 1540 nm region. The obtained NLPs exhibit narrow peak coherence of ∼231 fs.
In the genus
a new species, named
, has been recently described. Only cytogenetic data are available for the nuclear genome of this species. In this work, we characterize the satellitome of the
...genome that presents 16 different families, including telomeric sequences, and they represent 1.24% of the genome. The first satellite DNA family (TaquSat1-183) represents 0.558%, and six more abundant families, including TaquSat1-183, comprise 1.13%, while the remaining 11 sat-DNAs represent only 0.11%. The average A + T content of the SatDNA families was 50.43% and the median monomer length was 289.24 bp. The analysis of these SatDNAs indicated that they have different grades of clusterization, homogenization, and degeneration. Most of the satDNA families are present in the genomes of the other
species analyzed, while in the genomes of other more distant species of Talpidae, only some of them are present, in accordance with the library hypothesis. Moreover, chromosomal localization by FISH revealed that some satDNAs are localized preferentially on centromeric and non-centromeric heterochromatin in
and also in the sister species
karyotype. The differences observed between
and the close relative
and
suggested that the satellitome is a very dynamic component of the genomes and that the satDNAs could be responsible for chromosomal differences between the species. Finally, in a broad context, these data contribute to the understanding of the evolution of satellitomes on mammals.
In this study, we report the complete mitochondrial genome or mitogenome of the blister beetle Hycleus scutellatus, one endemic species from the Iberian Peninsula. The mitogenome was 16,035 base ...pairs in length, with an A + T content of 71.7%. It has 37 genes including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. To analyze the evolutionary position of H. scutellatus, we constructed a phylogenetic tree using all available mitogenomes from species of the family Meloidae. The results show that Hycleus species are very close to the genus Mylabris. We present here the mitogenome of H. scutellatus as a new resource to elucidate the phylogenetic relations among the Meloidea family, being this source very useful for future evolutionary analyses of blister beetles.
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