On the Synthesis of the Astronomically Elusive 1-Ethynyl-3-Silacyclopropenylidene (c-SiC4H2) Molecule in Circumstellar Envelopes of Carbon-rich Asymptotic Giant Branch Stars and Its Potential Role in the Formation of the Silicon Tetracarbide Chain (SiC4)

Organosilicon molecules such as silicon carbide (SiC), silicon dicarbide (c-SiC2), silicon tricarbide (c-SiC3), and silicon tetracarbide (SiC4) represent basic molecular building blocks connected to the growth of silicon-carbide dust grains in the outflow of circumstellar envelopes of carbon-rich asymptotic giant branch (AGB) stars. Yet, the fundamental mechanisms of the formation of silicon carbides and of the early processes that initiate the coupling of silicon-carbon bonds in circumstellar envelopes have remained obscure. Here, we reveal in a crossed molecular beam experiment contemplated with ab initio electronic calculations that the astronomically elusive 1-ethynyl-3-silacyclopropenylidene molecule (c-SiC4H2, Cs, X1A′) can be synthesized via a single-collision event through the barrierless reaction of the silylidyne radical (SiH) with diacetylene (C4H2). This system represents a benchmark of a previously overlooked class of reactions, in which the silicon-carbon bond coupling can be initiated by a barrierless and overall exoergic reaction between the simplest silicon-bearing radical (silylidyne) and a highly hydrogen-deficient hydrocarbon (diacetylene) in the inner circumstellar envelopes of evolved carbon-rich stars such as IRC+10216. Considering that organosilicon molecules like 1-ethynyl-3-silacyclopropenylidene might be ultimately photolyzed to bare carbon-silicon clusters like the linear silicon tetracarbide (SiC4), hydrogenated silicon-carbon clusters might represent the missing link eventually connecting simple molecular precursors such as silane (SiH4) to the population of silicon-carbide based interstellar grains ejected from carbon-rich AGB stars into the interstellar medium

METHODOLOGICAL AND TECHNOLOGICAL ASPECTS OF THE FUTURE TEACHER'S COMPETENCE FORMATION PROCESS MANAGEMENT

In the presentation materials of the article, being the result of many years of scientific studies of authors, the ideology of efficient and effective management of the future teacher's formation is reflected

OBJECTIVE CONTROL IN CONDITIONS OF PERSONALLY FOCUSED TRAINING PROCESS

On the example of tracking the mastering procedure (cognitive task) peculiarities the possibility to implement the technological scheme of objective control in education as the most important mechanism ensuring the efficiency of this process is revealed in the article through such parameter as awareness

Typical and Atypical Antipsychotic Drugs Increase Extracellular Histamine Levels in the Rat Medial Prefrontal Cortex: Contribution of Histamine H1 Receptor Blockade

Atypical antipsychotics such as clozapine and olanzapine have been shown to enhance histamine turnover and this effect has been hypothesized to contribute to their improved therapeutic profile compared to typical antipsychotics. In the present study, we examined the effects of antipsychotic drugs on histamine (HA) efflux in the mPFC of the rat by means of in vivo microdialysis and sought to differentiate the receptor mechanisms which underlie such effects. Olanzapine and clozapine increased mPFC HA efflux in a dose related manner. Increased HA efflux was also observed after quetiapine, chlorpromazine, and perphenazine treatment. We found no effect of the selective 5-HT2A antagonist MDL100907, 5-HT2c antagonist SB242084, or the 5-HT6 antagonist Ro 04-6790 on mPFC HA efflux. HA efflux was increased following treatment with selective H1 receptor antagonists pyrilamine, diphenhydramine, and triprolidine, the H3 receptor antagonist ciproxifan and the mixed 5-HT2A/H1 receptor antagonist ketanserin. The potential novel antipsychotic drug FMPD, which has a lower affinity at H1 receptors than olanzapine, did not affect HA efflux. Similarly, other antipsychotics with lower H1 receptor affinity (risperidone, aripiprazole, and haloperidol) were also without effect on HA efflux. Finally, HA efflux after antipsychotic treatment was significantly correlated with affinity at H1 receptors whereas nine other receptors, including 5-HT2A, were not. These results demonstrate that both typical and atypical antipsychotics increase mPFC histamine efflux and this effect may be mediated via antagonism of histamine H1 receptors

Spinodal Decomposition in Binary Gases

We carried out three-dimensional simulations, with about 1.4 million particles, of phase segregation in a low density binary fluid mixture, described mesoscopically by energy and momentum conserving Boltzmann-Vlasov equations. Using a combination of Direct Simulation Monte Carlo(DSMC) for the short range collisions and a version of Particle-In-Cell(PIC) evolution for the smooth long range interaction, we found dynamical scaling after the ratio of the interface thickness(whose shape is described approximately by a hyperbolic tangent profile) to the domain size is less than ~0.1. The scaling length R(t) grows at late times like t^alpha, with alpha=1 for critical quenches and alpha=1/3 for off-critical ones. We also measured the variation of temperature, total particle density and hydrodynamic velocity during the segregation process.Comment: 11 pages, Revtex, 4 Postscript figures, submitted to PR

Molecular Dynamics Simulation of Spinodal Decomposition in Three-Dimensional Binary Fluids

Using large-scale molecular dynamics simulations of a two-component Lennard-Jones model in three dimensions, we show that the late-time dynamics of spinodal decomposition in concentrated binary fluids reaches a viscous scaling regime with a growth exponent $n=1$, in agreement with experiments and a theoretical analysis for viscous growth.Comment: 4 pages, 3 figure

Metabolomics analysis of metabolic effects of nicotinamide phosphoribosyltransferase (NAMPT) inhibition on human cancer cells.

Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in cellular bioenergetics. It is responsible for converting nicotinamide to nicotinamide adenine dinucleotide, an essential molecule in cellular metabolism. NAMPT has been extensively studied over the past decade due to its role as a key regulator of nicotinamide adenine dinucleotide-consuming enzymes. NAMPT is also known as a potential target for therapeutic intervention due to its involvement in disease. In the current study, we used a global mass spectrometry-based metabolomic approach to investigate the effects of FK866, a small molecule inhibitor of NAMPT currently in clinical trials, on metabolic perturbations in human cancer cells. We treated A2780 (ovarian cancer) and HCT-116 (colorectal cancer) cell lines with FK866 in the presence and absence of nicotinic acid. Significant changes were observed in the amino acids metabolism and the purine and pyrimidine metabolism. We also observed metabolic alterations in glycolysis, the citric acid cycle (TCA), and the pentose phosphate pathway. To expand the range of the detected polar metabolites and improve data confidence, we applied a global metabolomics profiling platform by using both non-targeted and targeted hydrophilic (HILIC)-LC-MS and GC-MS analysis. We used Ingenuity Knowledge Base to facilitate the projection of metabolomics data onto metabolic pathways. Several metabolic pathways showed differential responses to FK866 based on several matches to the list of annotated metabolites. This study suggests that global metabolomics can be a useful tool in pharmacological studies of the mechanism of action of drugs at a cellular level

Purine metabolism scheme.

<p>ADA, adenosine deaminase; AICAR, 5-aminoimidazole-4-carboxamide ribonucleotide; AMP, adenosine monophosphate; GMP, guanosine monophosphate; GSK, inosine kinase; IMP, inosine monophosphate; IMPDH, inosine 5′-monophosphate dehydrogenase; PNase, purine 5′-nucleotidase; PNPase, purine-nucleoside phosphorylase; PRPP, 5-phospho-α-ribosyl-1-pyrophosphate; S-AMP, succinyl adenosine monophosphate.</p

One-way analysis of variance box plots illustrating the observed changes in the levels of aspartate, alanine, and N-carbamoyl-L-aspartate when treated with FK866 at 50 and 5 nM concentrations in A2780 (left panels) and HCT-116 (right panels) cells, respectively, with (+NA) and without (−NA) nicotinic acid addition.

<p>Grand mean is shown as a horizontal line located within panel. The y-axis illustrates normalized, log transformed, and scaled peak area. Dots represent samples. Group mean shown as a horizontal line within the box.</p

Unsupervised hierarchical clustering analysis of the metabolite levels in A2780 (left panels) and HCT-116 (right panels) cells after FK866 treatment at 50 and 5 nM concentrations, respectively, with (+NA) and without (−NA) nicotinic acid addition.

<p>Elevated metabolite levels are red and depressed ones are green. Each square represents the Pearson correlation coefficient between the metabolite in the row with the group in the column.</p