The effect of internal pressure on the tetragonal to monoclinic structural phase transition in ReOFeAs: the case of NdOFeAs

We report the temperature dependent x-ray powder diffraction of the quaternary compound NdOFeAs (also called NdFeAsO) in the range between 300 K and 95 K. We have detected the structural phase transition from the tetragonal phase, with P4/nmm space group, to the orthorhombic or monoclinic phase, with Cmma or P112/a1 (or P2/c) space group, over a broad temperature range from 150 K to 120 K, centered at T0 ~137 K. Therefore the temperature of this structural phase transition is strongly reduced, by about ~30K, by increasing the internal chemical pressure going from LaOFeAs to NdOFeAs. In contrast the superconducting critical temperature increases from 27 K to 51 K going from LaOFeAs to NdOFeAs doped samples. This result shows that the normal striped orthorhombic Cmma phase competes with the superconducting tetragonal phase. Therefore by controlling the internal chemical pressure in new materials it should be possible to push toward zero the critical temperature T0 of the structural phase transition, giving the striped phase, in order to get superconductors with higher Tc.Comment: 9 pages, 3 figure

Improving the Characterization of Radiologically Isolated Syndrome Suggestive of Multiple Sclerosis

OBJECTIVE: To improve the characterization of asymptomatic subjects with brain magnetic resonance imaging (MRI) abnormalities highly suggestive of multiple sclerosis (MS), a condition named as "radiologically isolated syndrome" (RIS). METHODS: Quantitative MRI metrics such as brain volumes and magnetization transfer (MT) were assessed in 19 subjects previously classified as RIS, 20 demographically-matched relapsing-remitting MS (RRMS) patients and 20 healthy controls (HC). Specific measures were: white matter (WM) lesion volumes (LV), total and regional brain volumes, and MT ratio (MTr) in lesions, normal-appearing WM (NAWM) and cortex. RESULTS: LV was similar in RIS and RRMS, without differences in distribution and frequency at lesion mapping. Brain volumes were similarly lower in RRMS and RIS than in HC (p<0.001). Lesional-MTr was lower in RRMS than in RIS (p = 0.048); NAWM-MTr and cortical-MTr were similar in RIS and HC and lower (p<0.01) in RRMS. These values were particularly lower in RRMS than in RIS in the sensorimotor and memory networks. A multivariate logistic regression analysis showed that 13/19 RIS had ≥70% probability of being classified as RRMS on the basis of their brain volume and lesional-MTr values. CONCLUSIONS: Macroscopic brain damage was similar in RIS and RRMS. However, the subtle tissue damage detected by MTr was milder in RIS than in RRMS in clinically relevant brain regions, suggesting an explanation for the lack of clinical manifestations of subjects with RIS. This new approach could be useful for narrowing down the RIS individuals with a high risk of progression to MS

The new european regulation on personal data protection: Significant aspects for data processing for scientific research purposes

Aim The paper investigates the new European Data Protection Regulation released in 2016. It highlights the data protection principles inspiring the Regulation and outlines its main innovative as well as critical aspects as regards the use of personal data for research purposes. Results: As far as scientific research is concerned, the new Regulation provides some interesting novelties in relation to informed consent and to use of personal data without consent. Conclusion: It is still early for the consideration of the new Regulation, in relation to which the transition period before it definitively comes into force in 2018 will be useful for making a complete and detailed assessment of its adequacy. However, it is precisely with reference to the collection of retrospective personal data that the greatest innovations are seen. It will therefore be interesting to follow the interpretative evolution of the principle of compatibility of purposes which renders - in fact - personal data already collected usable, even in the absence of consent from the data subject

Tumour necrosis factor alpha in segmental colitis associated with diverticula

The pathogenesis of segmental colitis associated with diverticula (SCAD) is unclear, but tumour necrosis factor alpha (TNF-alpha) has been shown to play a pivotal role in the pathogenesis of inflammatory bowel diseases. The aim of this study was to assess TNF-alpha levels in patients with SCAD. In a post hoc analysis of a prospective multicenter study, tissue samples from 13 patients diagnosed with SCAD were subjected to histological analyses. The severity of the inflammation was assessed by means of a histological score and histomorphometry (number of inflammatory cells/mm2). Immunohistochemical staining with an antibody against TNF-alpha was performed on all biopsies and the degree of staining expressed as the percentage of positive stromal cells/1000 counted (TNF-alpha score). Matched patients with irritable bowel syndrome (IBS) were used as controls. Over-expression of TNF-alpha was found in all SCAD patients (38.6 +/- 10.4%), and it was associated with a high histological score (2.5 +/- 0.5) and neutrophil cell count (16.3 +/- 3/mm2). These values were distinctly higher than those found in the IBS controls. Our data suggest that TNF-alpha activity is involved in SCAD pathogenesis, similarly to what occurs in Crohn's disease and ulcerative colitis

MRI in sarcoglycanopathies: a large international cohort study

OBJECTIVES: To characterise the pattern and spectrum of involvement on muscle MRI in a large cohort of patients with sarcoglycanopathies, which are limb-girdle muscular dystrophies (LGMD2C-2F) caused by mutations in one of the four genes coding for muscle sarcoglycans. METHODS: Lower limb MRI scans of patients with LGMD2C-2F, ranging from severe childhood variants to milder adult-onset forms, were collected in 17 neuromuscular referral centres in Europe and USA. Muscle involvement was evaluated semiquantitatively on T1-weighted images according to a visual score, and the global pattern was assessed as well. RESULTS: Scans from 69 patients were examined (38 LGMD2D, 18 LGMD2C, 12 LGMD2E and 1 LGMD2F). A common pattern of involvement was found in all the analysed scans irrespective of the mutated gene. The most and earliest affected muscles were the thigh adductors, glutei and posterior thigh groups, while lower leg muscles were relatively spared even in advanced disease. A proximodistal gradient of involvement of vasti muscles was a consistent finding in these patients, including the most severe ones. CONCLUSIONS: Muscle involvement on MRI is consistent in patients with LGMD2C-F and can be helpful in distinguishing sarcoglycanopathies from other LGMDs or dystrophinopathies, which represent the most common differential diagnoses. Our data provide evidence about selective susceptibility or resistance to degeneration of specific muscles when one of the sarcoglycans is deficient, as well as preliminary information about progressive involvement of the different muscles over time