Electron spectroscopy of carbon materials: Experiment and theory

We present a comparative spectroscopic study of carbon as graphite, diamond and C60 using C1s K-edge electron energy-loss spectroscopy (EELS), X-ray emission spectroscopy, and theoretical modelling. The first principles calculations of these spectra are obtained in the local density approximation using a self-consistent Gaussian basis pseudo-potential method. Calculated spectra show excellent agreement with experiment and are able to discriminate not only between various carbon hybridisations but also local variation in environment. Core-hole effects on the calculated spectra are also investigated. For the first time, the EEL spectrum of carbyne is calculated

Genome resource banking in the family Felidae

Many of the extant Felidae species are endangered or vulnerable. Others being not endangered as a whole species contain endangered subspecies. Only a very few cat species, besides domestic cats, are not in the risk group. Cryopreservation of embryos and gametes is a modern approach for ex situ mammalian genetic resources conservation. Freezing of semen has been successfully applied to the domestic cat and to more than 25 wild members of this family. However, embryos/oocytes cryopreservation was successful for only a small number of felids. Domestic cat and four wild Felidae species produced offspring after cryopreservation and subsequent embryo transfer. Regarding freezing of oocytes, so far different cryopreservation methods are still being experimentally tried exclusively for domestic cat. Genome Resource Bank (GRB) containing frozen semen of Amur leopard cat, bobcat and Eurasian lynx was established at the Institute of Cytology and Genetics, Novosibirsk. As a result of this project, original methods of feline semen freezing have been developed; embryos of domestic cat have been successfully frozen as well. Approaches to freeze domestic cat’s oocytes have also been tried. During this work, we combined biological and physical methods. In particular, the process of freezing embryos and oocytes was monitored with Raman spectroscopy. Different methods of frozen-thawed spermatozoa and embryonic viability testing were used in this study, including vital staining and subsequent fluorescent and light microscopy, and heterologous in vitro fertilization

Alterations in the social-conditioned place preference and density of dopaminergic neurons in the ventral tegmental area in Clsnt2-KO mice

The incidence of autistic spectrum disorders (ASD) constantly increases in the world. Studying the mechanisms underlying ASD as well as searching for new therapeutic targets are crucial tasks. Many researchers agree that autism is a neurodevelopmental disorder. Clstn2-KO mouse strain with a knockout of calsyntenin 2 gene (Clstn2) is model for investigating ASD. This study aims to evaluate the social-conditioned place preference as well as density of dopaminergic (DA) neurons in the ventral tegmental area (VTA), which belongs to the brain reward system, in the males of the Clstn2-KO strain using wild type C57BL/6J males as controls. Social-conditioned place preference test evaluates a reward-dependent component of social behavior. The results of this test revealed differences between the Clstn2-KO and the control males, as the former did not value socializing with the familiar partner, spending equal time in the isolationand socializing-associated compartments. The Clstn2-KO group entered both compartments more frequently, but spent less time in the socializingassociated compartment compared to the controls. By contrast, the control males of the C57BL/6J strain spent more time in socializing-associated compartment and less time in the compartment that was associated with loneness. At the same time, an increased number of DA and possibly GABA neurons labeled with antibodies against the type 2 dopamine receptor as well as against tyrosine hydroxylase were detected in the VTA of the Clstn2-KO mice. Thus, a change in social-conditioned place preference in Clstn2-KO mice as well as a higher number of neurons expressing type 2 dopamine receptors and tyrosine hydroxylase in the VTA, the key structure of the mesolimbic dopaminergic pathway, were observed

Neuronal density in the brain cortex and hippocampus in Clsnt2-KO mouse strain modeling autistic spectrum disorder

Autistic spectrum disorders (ASD) represent conditions starting in childhood, which are characterized by difficulties with social interaction and communication, as well as non-typical and stereotyping models of behavior. The mechanisms and the origin of these disorders are not yet understood and thus far there is a lack of prophylactic measures for these disorders. The current study aims to estimate neuronal density in the prefrontal cortex and four hippocampal subfields, i. e. СA1, СA2, СA3, and DG in Clstn2-KO mice as a genetic model of ASD. In addition, the level of neurogenesis was measured in the DG area of the hippocampus. This mouse strain was obtained by a knockout of the calsinthenin-2 gene (Clsnt2) in C57BL/6J mice; the latter (wild type) was used as controls. To estimate neuronal density, serial sections were prepared on a cryotome for the above-mentioned brain structures with the subsequent immunohistochemical labeling and confocal microscopy; the neuronal marker (anti-NeuN) was used as the primary antibody. In addition, neurogenesis was estimated in the DG region of the hippocampus; for this purpose, a primary antibody against doublecortin (anti-DCX) was used. In all cases Goat anti-rabbit IgG was used as the secondary antibody. The density of neurons in the CA1 region of the hippocampus was lower in Clstn2-KO mice of both sexes as compared with controls. Moreover, in males of both strains, neuronal density in this region was lower as compared to females. Besides, the differences between males and females were revealed in two other hippocampal regions. In the CA2 region, a lower density of neurons was observed in males of both strains, and in the CA3 region, a lower density of neurons was also observed in males as compared to females but only in C57BL/6J mice. No difference between the studied groups was revealed in neurogenesis, nor was it in neuronal density in the prefrontal cortex or DG hippocampal region. Our new findings indicate that calsyntenin-2 regulates neuronal hippocampal density in subfield-specific manner, suggesting that the CA1 neuronal subpopulation may represent a cellular target for earlylife preventive therapy of ASD

Effects of a high-fat diet on the lipid profile of oocytes in mice

There are evidences that obese women exhibit a detrimental oocyte quality. However, it remains unclear how this change is associated with obesity, indirectly – or directly through a change in the content and/or composition of lipids in oocytes. The aim of this work was to study effects of a high-fat diet applied to female donor mice on the amount and qualitative composition of lipids of immature and in vivo matured oocytes. A high-fat diet caused larger body weight in female mice compared with the control (p < 0.001; 44.77±1.46 and 35.22±1.57, respectively), and increased the blood levels of cholesterol (p < 0.05; 2.06±0.10 and 1.78±0.10, respectively) and triglycerides (p < 0.05; 2.13±0.23 and 1.49±0.21, respectively). At the same time, this diet does not affect the level of unsaturation of lipids in immature (0.207±0.004 in the experiment and 0.206±0.002 in the control) and matured oocytes (0.212±0.005 in the experiment and 0.211±0.003 in the control). Total lipid content increased during in vivo maturation of mouse oocytes. The amount of lipids was greater in mature oocytes in the experimental group compared to the control (p < 0.01; 8.15±0.37 and 5.83±0.14, respectively). An increase in intracellular lipid amount during oocyte maturation was revealed both after a standard diet (p < 0.05; 4.72±0.48 and 5.83±0.14, respectively) and after a fat-rich diet (p < 0.001; 3.45±0.62 and 8.15±0.37, respectively). Thus, during in vivo oocyte maturation in mice the content of intracellular lipids enhanced, the high-fat diet aggravated this dynamics of lipid increase during in vivo maturation of oocytes

USE OF HIGH SURFACE NANOFIBROUS MATERIALS IN MEDICINE

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Bromination of double-walled carbon nanotubes

Double-walled carbon nanotubes (DWCNTs) synthesized by catalytic chemical vapor deposition (CCVD) have been functionalized by bromine vapor at room temperature. At least two different bromine species were detected in the product using X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis. The primary form is negatively charged Br2 molecules exhibiting an intense resonance at ∼238 cm−1 in the Raman spectrum. The electron transfer from the nanotubes to the adsorbed molecules is detected from C 1s XPS and near-edge X-ray absorption fine structure spectra. The optical absorption spectra reveal that although the metallic nanotubes are more reactive to Br2, the outer semiconducting nanotubes also readily interact with Br2 adsorbates. The secondary bromine form is attributed to covalent C-Br bonding, and its possible sources are discussed in the light of quantum-chemical calculations. Analysis of the XPS, Raman, and optical absorption spectra of the Br-DWCNTs annealed at 100-170 ° C indicates preservation of a part of bromine molecules in samples that affects the electronic and vibration properties of nanotubes

Thermal Decomposition of Co-Doped Calcium Tartrate and Use of the Products for Catalytic Chemical Vapor Deposition Synthesis of Carbon Nanotubes.

Thermal decomposition of Co-doped calcium tartrate in an inert atmosphere or air was studied using thermogravimetric analysis and X-ray absorption fine structure (XAFS) spectroscopy. It was shown that the powder substance containing 4 at.% of cobalt completely decomposes within 650-730 °C, depending on the environment, and the formation of Co clusters does not proceed before 470 °C. The products of decomposition were characterized by transmission electron microscopy, XAFS, and X-ray photoelectron spectroscopy. Surfaceoxidized Co metal nanoparticles as large as ∼5.6 ( 1.2 nm were found to form in an inert atmosphere, while the annealing in air led to a wide distribution of diameters of the nanoparticles, with the largest nanoparticles (30-50 nm) mainly present as a Co3O4 phase. It was found that the former nanoparticles catalyze the growth of CNTs from alcohol while a reducing atmosphere is required for activation of the latter nanoparticles. We propose the scheme of formation of CaO-supported catalyst from Co-doped tartrate, depending on the thermal decomposition conditions