1,581 research outputs found

    Origin and spectroscopic determination of trigonal anisotropy in a heteronuclear single-molecule magnet

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    W-band ({\nu} ca. 94 GHz) electron paramagnetic resonance (EPR) spectroscopy was used for a single-crystal study of a star-shaped Fe3Cr single-molecule magnet (SMM) with crystallographically imposed trigonal symmetry. The high resolution and sensitivity accessible with W-band EPR allowed us to determine accurately the axial zero-field splitting terms for the ground (S =6) and first two excited states (S =5 and S =4). Furthermore, spectra recorded by applying the magnetic field perpendicular to the trigonal axis showed a pi/6 angular modulation. This behavior is a signature of the presence of trigonal transverse magnetic anisotropy terms whose values had not been spectroscopically determined in any SMM prior to this work. Such in-plane anisotropy could only be justified by dropping the so-called 'giant spin approach' and by considering a complete multispin approach. From a detailed analysis of experimental data with the two models, it emerged that the observed trigonal anisotropy directly reflects the structural features of the cluster, i.e., the relative orientation of single-ion anisotropy tensors and the angular modulation of single-ion anisotropy components in the hard plane of the cluster. Finally, since high-order transverse anisotropy is pivotal in determining the spin dynamics in the quantum tunneling regime, we have compared the angular dependence of the tunnel splitting predicted by the two models upon application of a transverse field (Berry-phase interference).Comment: 13 pages, 9 figure

    From juvenile parkinsonism to encephalitis lethargica, a new phenotype of post-streptococcal disorders: case report.

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    We report the case of a 16-year-old boy presented with a mild akinetic-rigid parkinsonism shortly after a post-streptococcal infection. After stopping corticoids, he had a rapid neurological deterioration to a fatal encephalitis lethargica-like syndrome. Serum analysis demonstrated consistently elevated anti-streptolysin-O. This case illustrates a new severe phenotype in the spectrum of the post-streptococcal disorders. This etiology should be considered in the differential diagnosis of a movement disorder with a rapid detrimental evolution

    Laser assisted flow deposition: a new method to grow ZnO

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    Zinc oxide (ZnO) has been one of the most studied materials in the last decades. Either as bulk material, epilayers or nanostructures, this direct wide band gap semiconductor is known to possess great potential for fundamental science and modern technology applications

    Intrathyroidal Ectopic Thymus: A Case Series

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    A retrospective study in tumour characteristics and clinical outcomes of overweight and obese women with breast cancer

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    Introduction Obesity and breast cancer are two major pathologies closely associated with increasing incidence and mortality rates, especially amongst women. The association between both diseases have been thoroughly discussed but much is still to uncover. Aim The aim of this study is to analyse tumour characteristics and clinical outcomes of overweight and obese women to disclosure potential associations and better understand the impact of obesity in breast cancer. Materials and methods Clinicopathological information of 2246 women were extracted from the institutional database of comprehensive cancer centre in Portugal diagnosed between 2012 and 2016. Women were stratified according to body mass index as normal, overweight, and obese. Patients’ demographic information and tumour features (age, family history, topographic localization, laterality, histological type, and receptor status) were taken as independent variables and overall survival, tumour stage, differentiation grade and bilaterality were considered clinical outcomes. Results The main results reveal that overweight and obesity are predominantly associated with worse outcomes in breast cancer patients. Obese patients present larger (p-value: 0.002; OR 1.422; 95% CI 1.134–1.783) and more poorly differentiated tumours (p-value: 0.002; OR 1.480; 95% CI 1.154–1.898) and tend to have lower overall survival although without statistical significance (p-value: 0.117; OR 1.309; 95% CI 0.934–1.833). Overweighted women are more likely to have bilateral breast cancer (p-value: 0.017; OR 3.076; 95% CI 1.225–7.722) than obese women. The results also reveal that overweight women present less distant metastasis (p-value: 0.024; OR 0.525; 95%CI 0.299–0.920). Topographic localization and laterality did not achieve statistical significance.Open access funding provided by FCT|FCCN (b-on). Author C.L. has received research support by “FCT—Fundação para a Ciência e Tecnologia” (Grant number [SFRH/BD/146489/2019])
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