Isotopic and spin selectivity of H_2 adsorbed in bundles of carbon nanotubes

Due to its large surface area and strongly attractive potential, a bundle of carbon nanotubes is an ideal substrate material for gas storage. In addition, adsorption in nanotubes can be exploited in order to separate the components of a mixture. In this paper, we investigate the preferential adsorption of D_2 versus H_2(isotope selectivity) and of ortho versus para(spin selectivity) molecules confined in the one-dimensional grooves and interstitial channels of carbon nanotube bundles. We perform selectivity calculations in the low coverage regime, neglecting interactions between adsorbate molecules. We find substantial spin selectivity for a range of temperatures up to 100 K, and even greater isotope selectivity for an extended range of temperatures,up to 300 K. This isotope selectivity is consistent with recent experimental data, which exhibit a large difference between the isosteric heats of D_2 and H_2 adsorbed in these bundles.Comment: Paper submitted to Phys.Rev. B; 17 pages, 2 tables, 6 figure

Angiotensin II involvement in the development and persistence of amphetamine-induced sensitization: Striatal dopamine reuptake implications

Impact Factor: 2023 (2024 update): 2.7Fil: Basmadjian, Osvaldo M. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacología; Argentina.Fil: Basmadjian, Osvaldo M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Farmacología Experimental de Córdoba; Argentina.Fil: Occhieppo, Victoria B. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacología; Argentina.Fil: Occhieppo, Victoria B. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Farmacología Experimental de Córdoba; Argentina.Fil: Montemerlo, Antonella E. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Montemerlo, Antonella E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-Química de Córdoba; Argentina.Fil: Rivas, Gustavo A. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Rivas, Gustavo A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-Química de Córdoba; Argentina.Fil: Rubianes, María D. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Rubianes, María D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-Química de Córdoba; Argentina.Fil: Baiardi, Gustavo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Neurofarmacología; Argentina.Fil: Baiardi, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Bregonzio, Claudia. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Bregonzio, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Farmacología Experimental de Córdoba; Argentina.Amphetamine (AMPH) exposure induces behavioural and neurochemical sensitization observed in rodents as hyperlocomotion and increased dopamine release in response to a subsequent dose. Brain Angiotensin II modulates dopaminergic neurotransmission through its AT1 receptors (AT1-R), positively regulating striatal dopamine synthesis and release. This work aims to evaluate the AT1-R role in the development and maintenance of AMPH-induced sensitization. Also, the AT1-R involvement in striatal dopamine reuptake was analysed. The sensitization protocol consisted of daily AMPH administration for 5 days and tested 21 days after withdrawal. An AT1-R antagonist, candesartan, was administered before or after AMPH exposure to evaluate the participation of AT1-R in the development and maintenance of sensitization, respectively. Sensitization was evaluated by locomotor activity and c-Fos immunostaining. Changes in dopamine reuptake kinetics were evaluated 1 day after AT1-R blockade withdrawal treatment, with or without the addition of AMPH in vitro. The social interaction test was performed as another behavioural output. Repeated AMPH exposure induced behavioural and neurochemical sensitization, which was prevented and reversed by candesartan. The AT1-R blockade increased the dopamine reuptake kinetics. Neither the AMPH administration nor the AT1-R blockade altered the performance of social interaction. Our results highlight the AT1-R's crucial role in AMPH sensitization. The enhancement of dopamine reuptake kinetics induced by the AT1-R blockade might attenuate the neuroadaptive changes that lead to AMPH sensitization and its self-perpetuation. Therefore, AT1-R is a prominent candidate as a target for pharmacological treatment of pathologies related to dopamine imbalance, including drug addiction and schizophrenia. Datos de investigación. Todos los datos en los que se basan los resultados están plenamente disponibles en https://rdu.unc.edu.ar/handle/11086/18306info:eu-repo/semantics/publishedVersionFil: Basmadjian, Osvaldo M. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacología; Argentina.Fil: Basmadjian, Osvaldo M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Farmacología Experimental de Córdoba; Argentina.Fil: Occhieppo, Victoria B. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacología; Argentina.Fil: Occhieppo, Victoria B. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Farmacología Experimental de Córdoba; Argentina.Fil: Montemerlo, Antonella E. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Montemerlo, Antonella E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-Química de Córdoba; Argentina.Fil: Rivas, Gustavo A. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Rivas, Gustavo A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-Química de Córdoba; Argentina.Fil: Rubianes, María D. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Rubianes, María D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-Química de Córdoba; Argentina.Fil: Baiardi, Gustavo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Neurofarmacología; Argentina.Fil: Baiardi, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Bregonzio, Claudia. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina.Fil: Bregonzio, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Farmacología Experimental de Córdoba; Argentina

Examination of transport equations pertaining to permeable elastic tubules such as Henle's loop

The transport equations applicable to loops of Henle and similar elastic permeable tubules were re-examined to assess the effect of radial transport resistance in the lumen and tubule geometry on solute transport. Active transport at the wall as well as external gradients equivalent to a 2--1,000-fold concentration increase per centimeter of distance were considered. Wall permeabilities and active transport constants were varied up to 2 . 10(-2) cm/s. It is shown that for conditions applicable to the loop of Henle, resistance to radial solute transfer in the lumen is negligible, both for passive and active transmural transport with concomitant water flux, and that axial dispersion further reduces that resistance. These conclusions apply equally to conical and elliptical geometries likely to arise in loop operation. The validity of Poiseuille's equation for these geometries is discussed. Ii is concluded that the one-dimensional transport equations are a valid representation of loop operation