102,897 research outputs found
Notule: 2143. Gagea apulica (Liliaceae). In: Bartolucci F., Nepi C., Domina G., Peruzzi L. (eds.), Notulae alla checklist della flora vascolare italiana: 20
No full textAbstract non disponibil
Introduzione. Fenomeni di generazione e media nell'età contemporanea
No full textIntroduction to the special issu
Antagonism of ethanol effects by Ro 15-4513: an electrophysiological analysis
No full textEthanol (ETH) and general anesthetics have been reported to facilitate the chloride channel opening, possibly, or at least partly, through an interaction with the GABA-benzodiazepine (BZ) receptor-gated chloride ionophore "supramolecular complex". Recently Ro 15-4513, a novel BZ ligand, has been indicated as a potent and selective antagonist of various ETH-induced behavioral and biochemical effects. However, since its precise characterization is still a matter of debate, we have tested and compared the effect of Ro 15-4513, as well as its antagonism against ETH, in two objective electrophysiological parameters, i.e., the electroencephalograph (EEG) pattern in freely moving rats and single unit activity of reticulata neurons. Ro 15-4513 produced an EEG state of alertness and antagonized the behavioral impairment and the EEG deterioration by ETH. However, while its protective action was consistent against moderate doses (2 g/kg) of ETH, it was much less evident versus higher doses (4 and 8 g/kg). On reticulata cells, Ro 15-4513 potently stimulated their spontaneous firing and reversed the depression by both ETH and Na-pentobarbital. Moreover, the beta-carboline DMCM also had similar effects. The "pure" BZ antagonist Ro 15-1788 was completely inefective against ETH, yet fully cancelled the reversing actions of Ro 15-4513 and DMCM upon ETH or Na-pentobarbital effects. It is concluded that Ro 15-4513 behaves as a BZ inverse agonist, so that its opposition to ETH and Na-pentobarbital is probably the result of its "negative" coupling with the BZ recognition site that triggers the closing of chloride channels. It suggests that BZ inverse agonists might constitute, in the near future, a new class of analeptic drugs
Le interfacce della sintassi o la sintassi delle interfacce?
No full textIn this paper data from both argument structure and information structure are discussed to show that in both cases the interplay between syntax, semantics and pragmatics is needed to account for argument interpretation and word order phenomena in the languages of the world. This leads us to conclude that there is neither an autonomous level of syntax nor its centrality to interpret the data under discussion
(-)Sulpiride activates the firing rate and tyrosine hydroxylase activity of dopaminergic neurons in unanesthetized rats
No full textNumerical investigation of film thickness and wave statistics in gas-liquid downwards annular flows
No full textTwo-phase gas-liquid annular flows are observed in a broad range of industrial processes, such as production and pipeline systems for oil and gas distribution, steam generators, boiling water reactors, and emergency core cooling facilities to protect nuclear reactors.
Although the global flow characteristics of annular gas-liquid flows have been studied experimentally for more than 50 years, their numerical modelling is still immature.
We present a computational fluid dynamics model based on the volume of fluid method for simulating annular gas-liquid flows, focusing on the regular wave flow regime. We performed transient simulations on a 3-D domain using a commercial code (ANSYS Fluent 2021 R1). The mesh sensitivity analysis indicates that a very fine mesh must be used near the pipe wall to capture the liquid-gas interface correctly (Fig. 1).
The code is validated through available experimental data [1] regarding topological flow properties. In particular, we considered mean film thickness, film roughness, base film thickness, and wave film thickness. We studied two operating conditions. The first is characterized by liquid and gas Reynolds numbers of 1 250 and 25 000, respectively. The second has the same liquid Reynolds number as the first, but the gas Reynolds number is increased to 30 000.
A post-processing procedure is implemented to obtain the time traces of film thickness at 12 circumferential positions to capture the asymmetries in the flow.
The numerical values of the quantities analyzed are in good agreement with the experimental findings, with a maximum error of 21.02% concerning the wave film thickness. The errors regarding the mean film thickness and film roughness are less than 10% for both the case studies.
Considering the film thickness of time traces at different circumferential positions, we calculated the cross-correlation coefficients between them. The high values of the cross-correlation coefficients indicate that waves are coherent over the circumference of the pipe, following the experimental findings.
Finally, to better understand wave activities, we generated the power spectral density functions for the two cases studied. They are characterized by a quasi-linear power decay, similar to that of the Kolmogorov spectrum for homogeneous and isotropic turbulence, which becomes slightly steeper for the case characterized by a higher gas Reynolds number, in accordance with the experimental data
Reduction of reticulata neuronal activity by zolpidem and alpidem, two imidazopyridines with high affinity for type I benzodiazepine receptors
No full textZolpidem and alpidem, two imidazopyridines with high affinity for the type I benzodiazepine recognition site, have recently been proposed as preferential hypnotic (zolpidem) and anxiolytic (alpidem) drugs notable for the minor incidence of side-effects. To further characterize the molecular mechanism involved in the action of these drugs, we studied their effects in comparison with those of diazepam on the spontaneous electrical activity of substantia nigra pars reticulata (SNR) neurons. These cells have been shown to be extremely sensitive to various positive and negative modulators of GABAergic transmission. All three drugs consistently produced a dose-dependent (0.03-8.0 mg/kg i.v.) inhibition of the firing of SNR cells when administered as a single bolus. However, zolpidem was more potent and efficacious than diazepam or alpidem. The ID50s were 0.076, 0.492 and 0.821 mg/kg, respectively. When the drugs were injected in exponentially (ratio 2) increasing doses up to 8.0 mg/kg, the rank order for tachyphylaxis was zolpidem much greater than diazepam greater than alpidem. Since the effects of the drugs were abolished and prevented by a small dose (0.5 mg/kg i.v.) of flumazenil (Ro 15-1788), it is likely that the effects were mediated through activation of benzodiazepine receptors. The results indicate that the hypnotic, zolpidem, has a more potent inhibitory action on SNR cell activity than the anxiolytics, alpidem and diazepam
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