Tricalcium silicate Ca3SiO5 superstructure analysis: a route towards the structure of the M1 polymorph

International audienceIn this paper, we present a structural model for the M1 polymorph of tricalcium silicate Ca3SiO5 from Powder X-Ray Diffraction (XRD) data, including weak intensity superstructure Bragg lines. As no single crystal is available, this structural model has been deduced using the structural relationships found between the previously known triclinic and monoclinic M3 polymorphs. We find that the better starting set of atomic positions for Rietveld refinement is the triclinic set and not the monoclinic set. A key observation is that the monoclinic M1 structure is closer to the low temperature triclinic T3 structure (within the Golovastikov model) than to the higher temperature monoclinic M3 structure. The unit cell and the set of atomic positions of the two best models, called 3Pc and 3Pn models, are provided. We prefer the 3Pc model for it better reproduces the weak characteristic Bragg lines of the superstructure

Long-Term Factors Associated With Falls and Fractures Poststroke

Background: Risk factors for poststroke falls and fractures remain poorly understood. This study aimed to evaluate which factors increased risk of these events after stroke. Methods: Data from 7,267 hospitalized stroke patients were acquired from the Norfolk and Norwich University Hospital Stroke Register from 2003–2015. The impacts of multiple patient level and stroke characteristics and comorbidities on post-discharge falls and fractures were assessed. Univariate and multivariable models were constructed, adjusting for multiple confounders, using binary logistic regression for short-term analysis (up to 1-year post-discharge) and Cox-proportional hazard models for longer term analysis (1–3, 3–5, and 0–10 years follow-up). Results: The mean age (SD) was 76.3 ± 12.1 years at baseline. 1,138 (15.7%) participants had an incident fall; and 666 (9.2%) an incident fracture during the 10-year follow-up (total person years = 64,447.99 for falls and 67,726.70 for fractures). Half of the sample population were females (50.6%) and the majority had an ischemic stroke (89.8%). After adjusting for confounders: age, sex, previous history of falls, and atrial fibrillation were associated with an increased risk of both falls and fractures during follow-up. Furthermore, chronic kidney disease and hyperlipidemia were associated with an increased risk of falls, while previous stroke/transient ischemic attack increased fracture risk. Total anterior circulation stroke and a prestroke modified Rankin Scale score of 3–5 were associated with decreased risk of both events, with hypertension and cancer decreasing risk of falls only. Conclusion: We identified demographic, stroke-related, and comorbid factors associated with poststroke falls and fracture incidence. Further studies are required to examine and establish the relationship between reversible factors and further explore the role of preventative measures to prevent poststroke falls and fractures

Brainstem infarction in a patient with internal carotid dissection and persistent trigeminal artery: a case report

<p>Abstract</p> <p>Background</p> <p>The primitive trigeminal artery (PTA) is the most commonly described fetal anastomosis between the carotid and vertebrobasilar circulations.</p> <p>Case presentation</p> <p>We report a 42-year-old patient presenting with internal carotid dissection, and imaging features of brainstem infarction.</p> <p>Conclusion</p> <p>Based on the imaging studies we presume occlusive carotid dissection with extensive thrombosis within a persistent trigeminal artery as the cause of this brainstem ischemia.</p

10Kin1day: a bottom-up neuroimaging initiative

We organized 10Kin1day, a pop-up scientific event with the goal to bring together neuroimaging groups from around the world to jointly analyze 10,000+ existing MRI connectivity datasets during a 3-day workshop. In this report, we describe the motivation and principles of 10Kin1day, together with a public release of 8,000+ MRI connectome maps of the human brain

Historical Neurology and Neurosurgery On the Names of Babiński

ABSTRACT:The 100th anniversary of the discovery of the extensor plantar response will be celebrated in 1996. It was Joseph François Félix Babinski who became known worldwide for the sign that bears his name. In order to help Joseph in establishing his career, brother Henri gave up his aspirations and abandoned engineering. Clovis Vincent, ‘father’ of French neurosurgery and pupil of Joseph, stated: “Joseph Babinski lived for science, and Henri lived for his brother; without Henri Babinski, Joseph would not have accomplished that much”. However, Henri’s name became famous in all Paris for a cookbook Gastronomie Pratique written under the pseudonym of ‘Ali-Bab.’ Throughout Joseph’s career his surname remained distorted despite his own efforts to spell and pronounce it correctly. Several people can claim the name Babinski, but in neurology and neurosurgery there is only one, Joseph.</jats:p