Search results for "Cone"
showing 10 items of 772 documents
Initial results of NEXT-DEMO, a large-scale prototype of the NEXT-100 experiment
2013
NEXT-DEMO is a large-scale prototype of the NEXT-100 detector, an electroluminescent time projection chamber that will search for the neutrinoless double beta decay of Xe-136 using 100-150 kg of enriched xenon gas. NEXT-DEMO was built to prove the expected performance of NEXT-100, namely, energy resolution better than 1% FWHM at 2.5MeV and event topological reconstruction. In this paper we describe the prototype and its initial results. A resolution of 1.75% FWHM at 511 keV (which extrapolates to 0.8% FWHM at 2.5 MeV) was obtained at 10 bar pressure using a gamma-ray calibration source. Also, a basic study of the event topology along the longitudinal coordinate is presented, proving that it…
Relativistic MHD simulations of extragalactic jets
2005
We have performed a comprehensive parameter study of the morphology and dynamics of axisymmetric, magnetized, relativistic jets by means of numerical simulations. The simulations have been performed with an upgraded version of the GENESIS code which is based on a second-order accurate finite volume method involving an approximate Riemann solver suitable for relativistic ideal magnetohydrodynamic flows, and a method of lines. Starting from pure hydrodynamic models we consider the effect of a magnetic field of increasing strength (up to β ≡ |b|2/2p ≈ 3.3 times the equipartition value) and different topology (purely toroidal or poloidal). We computed several series of models investigating the …
Dal martire al cacciatore. Traduzioni intersemiotiche dell’eroismo antimafia
2022
Questo contributo muove da un'analisi comparativa tra la biografia di Alfonso Sabella "Cacciatore di mafiosi" (Mondadori, 2008) e le prime due stagioni della fiction Rai "Il Cacciatore" (2018-2020), tratte dal libro. L'obbiettivo è problematizzare questo processo di traduzione intersemiotica alla luce dell'evoluzione dei modelli d'eroismo dei personaggi. Nel saggio, ricolleghiamo questa evoluzione a una riflessione più generale sulla natura transmediale della memoria collettiva, sempre più legata allo spettacolo del passato costruito dai media, che ibridano tra loro generi diversi. Per situare le tendenze contemporanee della memoria dell'eroismo antimafia all'interno di una genealogia pià a…
Preferred dimerization of tetra-tolyl- and tetra-tosylurea derivatives of flexible and rigidified calix[4]arenes
2004
The dimerization of tetratolyl- and tetratosyl-urea derivatives 1 and 2, derived from a tetrapentoxy calix[4]arene in the cone conformation and of the corresponding tetra-urea derivatives 3 and 4, in which the cone conformation is rigidified by the two crown-3 tethers, have been studied. All six possible equimolar mixtures were examined by 1H NMR using CDCl3 and CD2Cl2 as solvents. While no heterodimers are found for the combinations 1/3 and 2/4 in either solvent, all remaining combinations lead to the (exclusive) formation of heterodimers in CD2Cl2. In CDCl3 heterodimers are only observed for the combinations of 3 with 2 or 4. These results are discussed in terms of entropic and enthalpic …
A combined NMR, DFT, and X-ray investigation of some cinchona alkaloid O-ethers.
2008
Structures and conformational behavior of several cinchona alkaloid O-ethers in the solid state (X-ray), in solution (NMR and DFT), and in the gas phase (DFT) were investigated. In the crystal, O-phenylcinchonidine adopts the Open(3) conformation similar to cinchonidine, whereas the O-methyl ether derivatives of both cinchonidine and cinchonine are packed in the Closed(1) conformation. Dynamic equilibria in solutions of the alkaloids were revealed by combined experimental-theoretical spin simulation/iteration techniques for the first time. In the (1)H NMR spectra in CDCl3 and toluene-d8 at room temperature, Closed(1) conformation was observed for the O-silyl ethers as a separate set of sign…
Synthesis and Anti-Tumor Activity of Novel Aminomethylated Derivatives of Isoliquiritigenin
2014
A series of new aminomethylated derivatives of isoliquiritigenin was synthesized. The structures of the compounds were confirmed by IR, MS, NMR, 13C-NMR and elemental analyses. Cytotoxic activities of these derivatives towards the human prostatic cell line PC-3, human mammary cancer cell line MCF-7 and human oophoroma cell line HO-8910 in vitro were tested. The IC50 values showed cytotoxic activities of some of these new derivatives were relatively strong. Furthermore, tumor growth inhibition in vivo of aminomethylated derivatives of isoliquiritigenin 15 was superior to that of isoliquritigenin and reached inhibition rates of 71.68%. The detailed synthesis, spectroscopic data, biological an…
El modelo de Ausubel en la didáctica de la física : una aproximanción experimental al proceso de E/A de contenidos que presentan constructos poco ela…
1993
Resumen basado en el de la publicación Resumen en inglés Se muestran los resultados de una investigación sobre educación física sobre «Magnetismo» en la escuela secundaria. Se investiga un enfoque constructivista para el diseño instruccional basado en el modelo de Ausubel en el tratamiento de temas en el cual los alumnos tienen representaciones conceptuales pobres y marcos alternativos. Se muestran los primeros resultados con respecto al aprendizaje inmediato y duradero. ESP
The desert gerbil Psammomys obesus as a model for metformin-sensitive nutritional type 2 diabetes to protect hepatocellular metabolic damage: Impact …
2017
Introduction While metformin (MET) is the most widely prescribed antidiabetic drug worldwide, its beneficial effects in Psammomys obesus (P. obesus), a rodent model that mimics most of the metabolic features of human diabetes, have not been explored thoroughly. Here, we sought to investigate whether MET might improve insulin sensitivity, glucose homeostasis, lipid profile as well as cellular redox and energy balance in P. obesus maintained on a high energy diet (HED). Materials and methods P. obesus gerbils were randomly assigned to receive either a natural diet (ND) consisting of halophytic plants (control group) or a HED (diabetic group) for a period of 24 weeks. MET (50 mg/kg per os) was…
Improved method for cannula fixation for long-term intracerebral brain infusion
2017
Abstract Background Implanted osmotic minipumps are commonly used for long-term, brain-targeted delivery of a wide range of experimental agents by being connected to a catheter and a cannula. During the stereotactical surgery procedure, the cannula has to be placed correctly in the x-y directions and also with respect to the injection point in the z-direction (deepness). However, the flat fixation base of available cannula holders doesn’t allow an easy, secure fixation onto the curve-shaped skull. New method We have developed a modified method for a better fixation of the cannula holder by using an easy-to-produce, skull-shaped silicone spacer as fixation adapter. Results We describe the ap…
Effect of metal ion catalyzed oxidation of rifamycin SV on cell viability and metabolic performance of isolated rat hepatocytes.
1991
The effect of rifamycin SV on metabolic performance and cell viability was studied using isolated hepatocytes from fed, starved and glutathione (GSH) depleted rats. The relationships between GSH depletion, nutritional status of the cells, glucose metabolism, lactate dehydrogenase (LDH) leakage and malondialdehyde (MDA) production in the presence of rifamycin SV and transition metal ions was investigated. Glucose metabolism was impaired in isolated hepatocytes from both fed and starved animals, the effect is dependent on the rifamycin SV concentration and is enhanced by copper (II). Oxygen consumption by isolated hepatocytes from starved rats was also increased by copper (II) and a partial i…