2 results
Low-frequency rTMS inhibits the anti-depressive effect of ECT. A pilot study
- Poul Erik Buchholtz, Mahmoud Ashkanian, Simon Hjerrild, Line Kirstine Hauptmann, Torben Albert Devantier, Paulina Jensen, Sanne Wissing, Mette Viller Thorgaard, Laerke Bjerager, Julie Lund, Anja Johnsen Alrø, Maria Simonsen Speed, Rene Børge Korsgaard Brund, Poul Videbech
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- Journal:
- Acta Neuropsychiatrica / Volume 32 / Issue 6 / December 2020
- Published online by Cambridge University Press:
- 27 July 2020, pp. 328-338
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- Article
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Objective:
Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has been shown to have a statistically and clinically significant anti-depressant effect. The present pilot study was carried out to investigate if right prefrontal low-frequency rTMS as an add-on to electroconvulsive therapy (ECT) accelerates the anti-depressant effect and reduces cognitive side effects.
Methods:In this randomised, controlled, double-blind study, thirty-five patients with major depression were allocated to ECT+placebo or ECT+low-frequency right prefrontal rTMS. The severity of depression was evaluated during the course using the Hamilton scale for depression (the 17-item as well as the 6-item scale) and the major depression inventory (MDI). Furthermore, neuropsychological assessment of cognitive function was carried out.
Results:The study revealed no significant difference between the two groups for any of the outcomes, but with a visible trend to lower scores for MDI after treatment in the placebo group. The negative impact of ECT on neurocognitive functions was short-lived, and scores on logical memory were significantly improved compared to baseline 4 weeks after last treatment. The ECT-rTMS group revealed generally less impairment of cognitive functions than the ECT-placebo group.
Conclusion:The addition of low-frequency rTMS as an add-on to ECT treatment did not result in an accelerated response. On the contrary, the results suggest that low-frequency rTMS could inhibit the anti-depressant effect of ECT.
Hydrogen Sorption in Magnesium Nanoparticles: Size- and Surface-related Phenomena
- Luca Pasquini, Elsa Callini, Emanuela Piscopiello, Amelia Montone, Torben René Jensen, Marco Vittori Antisari, Ennio Bonetti
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1216 / 2009
- Published online by Cambridge University Press:
- 31 January 2011, 1216-W05-04
- Print publication:
- 2009
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- Article
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The aim of this work is the investigation of the metal-hydride transformation in magnesium (Mg) nanoparticles both as a function of particle size and in response to surface functionalization by clusters of transition metals (TM): Pd, Ni, Ti.
Mg nanoparticles were synthesized by the inert-gas condensation technique, which yields single crystals with six-fold symmetry whose average size can be controlled by tuning the inert gas pressure. After the synthesis the nanoparticles were passivated by slow exposure to oxygen, obtaining a core-shell morphology where a metallic core is coated by a MgO shell of about 5 nm thickness.
The material structure was investigated by Transmission Electron Microscopy (TEM), also in High Resolution (HRTEM) mode, and by X-Ray Diffraction (XRD). The sorption kinetics were analysed by a volumetric Sievert apparatus, which also allowed for a determination of the activation energies.
Small nanoparticles (≈35 nm) display interesting kinetics with gravimetric capacity of 4.5 wt.% at saturation, limited by the oxide fraction. Hydride formation proceeds by one-dimensional growth controlled by diffusion through the hydride, while the reverse transformation to metal involves interface-controlled three-dimensional growth of nuclei formed at constant rate.
On the contrary, large nanoparticles (≈450 nm) exhibit very low reactivity due to reduced probability of hydrogen dissociation/recombination and nucleation at the particle surface. For this reason, large nanoparticles were surface-decorated by TM through in situ evaporation in the inert-gas condensation chamber. This procedure results in clusters of 3-4 nm located over a portion of the MgO shell, as shown by XRD and HRTEM on Pd-decorated sample. This treatment results in dramatically improved hydrogen sorption behavior. In fact, previously inert nanoparticles now exhibit of up to 5.6 wt.%.
Real-time diffraction studies using Synchrotron Radiation were carried out during hydrogen desorption on the Pd-decorated nanoparticles. We clearly show that a Mg-Pd intermetallic phase is formed after the first heating treatment and takes active part in the transformation.