The influence of the radiative non-symmetric ion-atom collisions on the stellar atmospheres in VUV region

The aim of this work is to draw attention to the processes of radiative charge exchange in non-symmetric ion-atom collisions as a factor of influence on the opacity of stellar atmospheres in VUV region. For that purpose calculations of the spectral absorption coefficients for several ion-atom systems, namely: He + H$^{+}$ and H + X$^{+}$, where X = Na and Li have been performed. On chosen examples it has been established that the examined processes generate rather wide molecular absorption bands in the VUV region, which should be taken into account for the interpretation of data obtained from laboratory measurements or astrophysical observations. In this paper the potential significance is discussed of the considered radiative processes for DB white dwarfs and solar atmospheres, as well as for the atmospheres of the so-called lithium stars

The ion-atom absorption processes as one of the factors of the influence on the sunspot opacity

As a continuation of the previous investigations of the symmetric and strongly non-symmetric ion-atom absorption processes in the far UV region within the models of the quiet Sun photosphere, these processes are studied here within a model of the sunspot. Here we mean the absorption processes in the H$(1s)$+H$^{+}$ and H$(1s)+X^{+}$ collisions and the processes of the photo-dissociation of the H$_{2}^{+}$ and H$X^{+}$ molecular ions, where $X$ is one of the metal atoms: $X=$Na, Ca, Mg, Si and Al. Obtained results show that the influence of the considered ion-atom absorption processes on the opacity of sunspots in the considered spectral region (110 nm $\lesssim \lambda \lesssim$ 230 nm) is not less and in some parts even larger than the influence of the referent electron-atom processes. In such a way, it is shown that the considered ion-atom absorption processes should be included \emph{ab initio} in the corresponding models of sunspots of solar-type and near solar-type stars. Apart of that, the spectral characteristics of the considered non-symmetric ion-atom absorption processes (including here the case $X$ = Li), which can be used in some further applications, have been determined and presented within this work.Comment: Accepted in Monthly Notices of the Royal Astronomical Societ

Excitation and deexcitation processes in atom-Rydberg atom collisions in helium-rich white dwarf atmospheres

We aim to show the importance of non-elastic excitation and deexcitation processes in $\textrm{He}^{*}(n)+ \textrm{He}(1s^{2})$ collisions with the principal quantum number $n \ge 3$ for helium-rich white dwarf atmospheres. We compare the efficiencies of these processes with those of the known non-elastic electron-$\textrm{He}^{*}(n)$ atom processes in the atmospheres of some DB white dwarfs. We show that in significant parts of the considered atmospheres, which contain weakly ionized layers (the ionization degree $\lesssim 10^{-3}$), the influence of the studied atom-Rydberg atom processes on excited helium atom populations is dominant or at least comparable to the influence of the concurrent electron-$\textrm{He}^{*}(n)$-atom processes.Comment: Astronomy & Astrophysics, Accepted: 14 February 201

Ion-atom radiative processes in the solar atmosphere: quiet Sun and sunspots

In the previous works the significance of the symmetric and non-symmetric ion-atom absorption processes in far UV and EUV regions within a model of the quiet Sun atmosphere, has been studied. The considered processes were the processes of the photo-dissociation of the molecular ions H$_{2}^{+}$ and H$X^{+}$ and absorption processes in H+H$^{+}$ and H$+X^{+}$ collisions, where $X$ denotes the metal atom. As the continuation of the previous investigation, these processes are considered also within the corresponding sunspot model. In this work the non-symmetric ion-atom absorption processes are considered with $X=$ Mg, Si, etc. It was analyzed the significance of such processes in far UV and EUV regions in comparison with the concurrent absorption processes, especially with the processes of the photo-ionization of the metal atoms (Na, Mg, Ca, etc.) which were not included in the consideration in the case of the quiet Sun atmosphere. From our analysis it follows that the non-symmetric ion-atom absorption processes considered here, are significant not only for quiet Sun modeling but also for sunspots and should be included {\it ab initio} in both cases.Comment: accepted in Advances in Space Researc

Serum N-acetyl-beta-D-glucosaminidase profiles in type 1 diabetes secondary complications: Causes of changes and significance of determination

The connection between changes in the activity of serum N-acetyl-beta-D-glucosaminidase (NAG, E.C.3.2.1.30) and iso-enzymes and degree of secondary complications was analyzed in four groups of type 1 diabetic patients (n=69): without complications (n=22); with retinopathy (n=16); with retinopathy and polyneuropathy (n= 13), and with retinopathy, neuropathy, and nephropathy (n=18). In all groups statistically significant higher (P lt 0.001) percent fraction of A form (83.84 +/- 6.09, 84.37 +/- 5.74, 81.76 +/- 6.02, 76.37 +/- 7.38%, resp.) and lower (P lt 0.001, P lt 0.01) fraction of B form (15.87 +/- 5.65, 15.66 +/- 5.74, 18.33 +/- 5.98, 23.63 +/- 7.38, resp.) in total NAG compared with the control (A = 69.38 +/- 4.79%, B = 30.61 +/- 4.78%) were found. The differences in A as well as B forms between diabetic groups were not statistically significant. Significant strong positive correlations between total NAG and glycemia (0.494-0.623), total NAG and A form (0.934-0.966), and A form and glycemia (0.512-0.638) were found in all groups. No correlation was found between the fractions of B and A forms, except in the fourth group. The A form of diabetic patients in the fourth group was more acidic compared with the control and other diabetic groups. It was concluded that the changes in serum NAG and isoenzymic profiles in diabetes are the consequence of its increased exocytose, especially of the A form, in hyperglycemia and posttranslational modifications of iso-enzymes. The total activity of serum NAG and iso-enzymic profiles cannot be used for monitoring the development and distinction of type 1 diabetes secondary complications

The MOL-D database VAMDC node for molecular collisional and radiative processes

International audienceThe MOL-D database is a collection of collisional data and a web service within the Virtual Atomic and Molecular Data Centre (VAMDC, http://www.vamdc.eu). In this paper we report on the current stage of MOL-D development. This database and web service/interface is intended for modeling stellar atmospheres, laboratory plasmas, technological plasmas etc. For example, the data for hydrogen are important for elaboration of atmosphere models of solar and near solar type stars and for radiative transport consideration as well as for the kinetics of stellar and other astrophysical plasmas. The helium data are of interest particularly for investigation of helium-rich white dwarf atmospheres. Stage 1 of the development was done at the end of 2014 when all the existing calculated data for photodissociation cross-sections of hydrogen H <SUB>2</SUB> and helium He <SUB>2</SUB> molecular ions and the corresponding averaged thermal photodissociation cross-sections had been processed and integrated into the database. We are now beginning Stage 2 of the development of MOL-D. At the moment we are including new cross-sections and rate coefficients for processes which involve species such as HeH<SUP> </SUP>, LiH<SUP> </SUP>, NaH<SUP> </SUP>, SiH<SUP> </SUP> that are important for exploring the interstellar medium as well as for the early universe chemistry and for modeling stellar and solar atmospheres

HF electric properties of the astrophysical plasmas

International audienceThe HF characteristics of astrophysical plasmas was determined on the basis of numerically calculated values for the dense plasma conductivity in an external HF electric field. The examined range of plasma frequencies covers the IR, visible and UV regions and considers electronic number density and temperature important for different stellar models. The results presented here are important for the investigation of atmosphere plasmas of astrophysical objects, for example, white dwarfs with different atmospheric compositions (DA, DC etc.), and for the investigation of some other stars (M-type red dwarfs, Sun etc.) as well as for laboratory plasma research

Comparison of the dietary habits of normal subjects among five Mediterranean countries and with the traditional Mediterranean diet

abstrac

Application potential of biogenically synthesized silver nanoparticles using: Lythrum salicaria L. extracts as pharmaceuticals and catalysts for organic pollutant degradation

This study was designed to evaluate the optimal conditions for the eco-friendly synthesis of silver nanoparticles (AgNPs) using Lythrum salicaria L. (Lythraceae) aqueous extracts and their potential application and safe use. AgNPs synthesized using L. salicaria aerial parts (LSA-AgNPs) and root extract (LSR-AgNPs) were characterized by UV-Vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM/EDS), and X-ray powder diffraction (XRPD). Dynamic light scattering (DLS) was used for the determination of the size distribution profiles of the obtained nanoparticles. Both L. salicaria extracts showed high phenolic content, while the flavone C-glucosides orientin, vitexin, and isovitexin were detected in extracts using HPLC. The synthesized AgNPs displayed growth inhibition of the tested bacteria and fungi in concentrations between 0.156 and 1.25 mg mL-1. The studied nanoparticles also showed antioxidant potential and gained selectivity at different concentrations on different cancer cell lines. Concentrations of LSA-AgNPs were found to be 20.5 and 12 μg mL-1 towards A431 and SVT2, respectively, while LSR-AgNPs were effective only against A431 cancer cells (62 μg mL-1). The hemolytic activity of LSA-AgNPs in concentrations up to 150 μg mL-1 was not observed, while LSR-AgNPs in the highest applied concentration hemolyzed 2.8% of erythrocytes. The degradation possibility of Congo red and 4-nitrophenol using LSA-AgNPs and LSR-AgNPs as catalysts was also proven. The results indicate that L. salicaria may be used for the eco-friendly synthesis of AgNPs with possible applications as antimicrobial and selective cytotoxic agents towards cancer cell lines, as well as in catalytic degradation of pollutants