Predicted defect induced vortex core switching in thin magnetic nanodisks

We investigate the influence of artificial defects (small holes) inserted into magnetic nanodisks on the vortex core dynamics. One and two holes (antidots) are considered. In general, the core falls into the hole but, in particular, we would like to remark an interesting phenomenon not yet observed, which is the vortex core switching induced by the vortex-hole interactions. It occurs for the case with only one hole and for very special conditions involving the hole size and position as well as the disk size. Any small deformation in the disk geometry such as the presence of a second antidot changes completely the vortex dynamics and the vortex core eventually falls into one of the defects. After trapped, the vortex center still oscillates with a very high frequency and small amplitude around the defect center.Comment: 11pages, Revtex format, 17 figure

Extração de taninos de Acacia sp. com potencial uso na coagulação: um contributo para a bioeconomia

Coagulation-flocculation is one of the most important steps in water treatment. In Water Treatment Plants, pre-polymerized inorganic coagulants are traditionally used; however, recent studies have shown the potential of condensed tannins for the production of natural coagulants as an alternative to chemical coagulants. In this context, the present work intends to highlight the importance of the development of nature-based solutions that can be alternative to conventional processes, due to the environmental, social and economic benefits they can provide. The study focused on optimizing condensed tannin extraction process from Acacia dealbata barks, as a strategy for valuing forest residues, promoting the territory bioeconomy and sustainability. In the tested extraction conditions, the best yield was obtained at a temperature of 40 oC, using 50% ethanol (v/v) as the solvent, without stirring and an extraction time of 30 min. The highest concentrations of condensed tannins and phenolic compounds were observed in samples of Acacia sp. with higher vegetative development (trunk perimeter of 20 cm), corresponding to 246,2 ± 9,4 miligrams per gram of dry extract (mg ges-1) and 706,2 ± 27,2 mg ges-1, respectively.Este trabalho foi desenvolvido no âmbito do projeto TECH - Tecnologia, Ambiente, Criatividade e Saúde, Norte-01-0145-FEDER-000043, cofinanciado pelo Programa Operacional Regional do Norte (NORTE 2020), através do Portugal 2020 e do Fundo Europeu de Desenvolvimento Regional (FEDER). Leonel Nunes foi apoiado pela proMetheus - Unidade de Investigação & Desenvolvimento em Materiais, Energia e Ambiente para a Sustentabilidade- UIDP/05975/2020, financiado por fundos nacionais através de FCT — Fundação para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

The precuneal interhemispheric, trans-tentorial corridor to the pineal region and brainstem, surgical anatomy, and case illustration

Background The pineal region and dorsal midbrain are among the most challenging surgical targets. To approach lesions in this region that harbor a superior to inferior long axis, we describe the basic steps of the precuneal, interhemispheric, trans-tentorial approach and illustrate anatomical landmarks of this established, but not so popular, surgical trajectory.Method To study the anatomical landmarks and safety of this approach, the neurovascular anatomy was studied on 22 sides of 11 formalin-fixed latex-injected anatomical specimens. A step-by-step dissection of the precuneal interhemispheric trans-tentorial approach and study of the key anatomical landmarks was performed. An illustrative clinical case of a pontomesencephalic cavernous malformation (CM) resected through this approach is also detailed.Results The mean distance from the transverse sinus to the most posterior cortical vein draining into the superior sagittal sinus was 6.4 cm. The mean distance from the calcarine sulcus to the most posterior cortical vein was 5.3 cm. Key steps of the dissection are as follows: craniotomy exposing the posterior aspect of the superior sagittal sinus (SSS), durotomy and gentle retraction of the SSS edge, dissection of the interhemispheric fissure, linear incision of the tentorium that extends anteriorly to the incisura and lateral reflection of the tentorium, and arachnoidal dissection and exposure of the cerebellomesencephalic fissure.Conclusion The precuneal, interhemispheric, trans-tentorial approach affords excellent access to the falcotentorial junction, splenium, pineal region, quadrigeminal cistern, and dorsal pons once the cerebellomesencephalic fissure has been dissected