Search results for "STELLA"
showing 10 items of 1995 documents
A stellar flare-coronal mass ejection event revealed by X-ray plasma motions
2019
Coronal mass ejections (CMEs), often associated with flares, are the most powerful magnetic phenomena occurring on the Sun. Stars show magnetic activity levels up to 10^4 times higher, and CME effects on stellar physics and circumstellar environments are predicted to be significant. However, stellar CMEs remain observationally unexplored. Using time-resolved high-resolution X-ray spectroscopy of a stellar flare on the active star HR 9024 observed with Chandra/HETGS, we distinctly detected Doppler shifts in S XVI, Si XIV, and Mg XII lines that indicate upward and downward motions of hot plasmas (~10-25 MK) within the flaring loop, with velocity v~100-400 km/s, in agreement with a model of fl…
Evolutionary paths of binaries with a neutron star - I. The case of SAX J1808.4 - 3658
2018
The evolutionary status of the low mass X-ray binary SAX J1808.4-3658 is simulated by following the binary evolution of its possible progenitor system through mass transfer, starting at a period of $\sim$6.6 hr. The evolution includes angular momentum losses via magnetic braking and gravitational radiation. It also takes into account the effects of illumination of the donor by both the X-ray emission and the spin down luminosity of the pulsar. The system goes through stages of mass transfer and stages during which it is detached, where only the rotationally powered pulsar irradiates the donor. We show that the pulsar irradiation is a necessary ingredient to reach SAX J1808.4-3658 orbital pe…
Dexamethasone modulates α2-macroglobulin and apolipoprotein E gene expression in cultured rat liver fat-storing (Ito) cells
1991
Fat-storing (Ito) cells are perisinusoidal liver cells thought to play a central role in vitamin A metabolism and fibrogenesis. Glucocorticoids have been shown to be beneficial in the treatment of certain types of liver diseases by delaying the development of cirrhosis. To study the regulatory effects of dexamethasone on Ito cell gene expression, Ito cells were isolated from normal rat liver and primary cultures were established. The effect of dexamethasone on the synthesis of α2-macroglobulin, apolipoprotein E, fibronectin and actin was examined. Protein synthesis was studied both at the protein level and at the RNA level by means of biosynthetic labeling, immunoprecipitation followed by s…
A novel compound of triphenyltin(IV) with N-tert-butoxycarbonyl-L-ornithine causes cancer cell death by inducing a p53-dependent activation of the mi…
2017
The triphenyltin(IV) compound with N-tert-butoxycarbonyl-L-ornithine (Boc-Orn-OH), [Ph3Sn(Boc-Orn-O)], was synthesized and characterized by elemental analysis, FT-IR, solution1H,13C and119Sn NMR and ESI mass spectrometry. The organotin(IV) compound inhibited at very low micromolar concentrations the growth of human tumor cell lines HepG2 (hepatocarcinoma cells), MCF-7 (mammary cancer) and HCT116 (colorectal carcinoma) while it did not affect the viability of non-malignant human-derived hepatic cells Chang. The mechanism of the antiproliferative effect of Ph3Sn(Boc-Orn-O), investigated on human hepatoma HepG2 cells, was pro-apoptotic, being associated with externalization of plasma membrane …
Gramatica arabigo-española, vulgar, y literal : Con un diccionario arabigo-español, en que se ponen las voces mas usuales para una conversacion fam…
1775
Sig. [calderó]-2[calderó]4, [ ]1, A-Z4, Aa-Ll4, A-B4, C1 Ornament xil. a la port. Alguna nota a peu de p. - Reclams
High resolution Fourier transform infrared spectroscopy and analysis of the ν 6 band of jet-cooled Mo(CO) 6
2000
Abstract Rovibrational FTIR spectra of Mo(CO) 6 have been recorded in supersonic argon expansions at 0.004 cm −1 resolution. Rotational constants have been determined for the ν 6 fundamental band of Mo( 12 CO) 6 and for the parallel band of the symmetric top isotopomer Mo( 13 CO)( 12 CO) 5 . From these results, a precise estimate of the Coriolis parameter for the ν 6 band of the main isotopomer Mo( 12 CO) 6 is derived, necessary for the analysis of the ν 6 spectrum. The observation of an octahedral splitting clearly resolved for the highest J-lines in the R branch prompted the use of a specific treatment based on the tensorial formalism developed by J.P. Champion, M. Loete, G. Pierre (Spher…
Modeling And Measurements Of The Arc Plasma In A Mixture Of Gases
2006
Radial distributions of Ar mass fractions and temperatures in plasmas produced in a wall-stabilized arc have been calculated. Modeling have been performed for many different mixtures of Ar+N2 and three different arc currents. The obtained results show that the radial distributions of Ar mass fractions strongly depend on the chemical composition of the plasma. In plasmas containing large amount of Ar the distributions have local minima at the arc axis (in high temperature plasma regions), whereas in plasmas consisting mainly of nitrogen the distributions reveal maxima on the discharge axis. Those features seem to be connected with the dissociation of the nitrogen.
Temperature dependence of the rate constant of hydrogen isotope interactions with a lithium capillary-porous system under reactor irradiation
2013
Abstract Experiments with a sample of a lithium capillary-porous system (CPS) were performed at the reactor IVG-1.M of the Institute of Atomic Energy NNC RK to study the effects of neutron irradiation on the parameters of hydrogen isotope interactions with a lithium CPS. The absorption technique was used during the experiments, and this technique allowed the temperature dependences of the hydrogen isotope interaction rate constants with the lithium CPS to be obtained under various reactor powers. The obtained dependencies were used to determine the main interaction parameters: the activation energies and the pre-exponents of the Arrhenius dependence of the hydrogen interaction rate constant…
Introducción al conocimiento de las Bellas Artes, ó Diccionario manual de Pintura, Escultura, Arquitectura, Grabado, &c. ... : Dispuesto y recogido…
1788
Port. amb ornaments tip. Caplletres ornades i fris Sign.: [ ]1, *4, A-Fff4, Ggg2 Reclams
Contrafiguras de la Anunciación en los primeros libros de caballerías: del 'thalamus Virginis' a los avisos angélicos de nacimientos extraordinarios
2022
El artículo examina el papel decisivo que tuvieron que ejercer las Anunciaciones pintadas durante los siglos XIV y XV sobre escenas de alcoba descritas y, a veces, iluminadas en textos de ficción, doctrinales o científicos. Entre los enseres pintados de la habitación de la Virgen María destaca el lecho (thalamus Virginis) por su significado mariológico y cristológico. De manera que la imagen del anuncio de Gabriel a María, con el trasfondo de ese thalamus, sirvió también como modelo para imaginar e ilustrar anuncios o avisos de concepción extraordinaria efectuados por espíritus, ángeles o demonios. Se examinan algunos de los casos más destacados de estos textos e imágenes en los primeros im…