History of Spinal Neurosurgery and Spine Societies

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Scientific Assessment and Innovation in Neurosurgical Treatment Strategie

Cation-Dependent Intrinsic Electrical Conductivity in Isostructural Tetrathiafulvalene-Based Microporous Metal-Organic Frameworks

Isostructural metal–organic frameworks (MOFs) M[subscript 2](TTFTB) (M = Mn, Co, Zn, and Cd; H[subscript 4]TTFTB = tetrathiafulvalene tetrabenzoate) exhibit a striking correlation between their single-crystal conductivities and the shortest S···S interaction defined by neighboring TTF cores, which inversely correlates with the ionic radius of the metal ions. The larger cations cause a pinching of the S···S contact, which is responsible for better orbital overlap between pz orbitals on neighboring S and C atoms. Density functional theory calculations show that these orbitals are critically involved in the valence band of these materials, such that modulation of the S···S distance has an important effect on band dispersion and, implicitly, on the conductivity. The Cd analogue, with the largest cation and shortest S···S contact, shows the largest electrical conductivity, σ = 2.86 (±0.53) × 10[subscript –4] S/cm, which is also among the highest in microporous MOFs. These results describe the first demonstration of tunable intrinsic electrical conductivity in this class of materials and serve as a blueprint for controlling charge transport in MOFs with π-stacked motifs.United States. Department of Energy. Office of Basic Energy Sciences (Award DE-SC0006937)National Science Foundation (U.S.). Graduate Research Fellowship Program (Award 1122374)David & Lucile Packard Foundation (Fellowship

Les méningiomes intrâcraniens en milieu ivoirien. Étude d\'une serie chirurgicale

Objective To report our experience in the management of intracranial meningiomas. Methods Ninety-six (96) patients were treated for intracranial meningiomas in Abidjan between 1991 and 2001, confirmed by neuropathological examination. Results Meningiomas represented 33.43% of intracranial tumors. The average age of our patients was 43 years, from 7 to 72 years-old with a predominance of women: sex ratio 3/2. Headaches were the most frequent sign. Post operative mortality was 12. 63%. Meningothelial meningioma was the most frequent (55.78%) histopathological entity. Conclusion Meningioma represented the most frequent intracranial tumor in Ivory Coast. Our patients were young. More prospective studies - clinical, biology, neuroimaging - are request in order to appreciate all the features of this pathology. Objectif Présenter les particularités épidémiologiques, cliniques et thérapeutiques des méningiomes intracrâniens en milieu sous médicalisé, à travers l\'expérience ivoirienne. Matériel et Méthode Il s\'agit d\'une étude rétrospective d\'une série de 96 cas de méningiomes intracrâniens traités au service de neurochirurgie d\'Abidjan de 1991 à 2001.Le diagnostic pré chirurgical ou avant la biopsie fait par le scanner était confirmé par l\'examen neuro-pathologique. Le suivi postopératoire a été clinique et quelquefois un examen tomodensitométrique a été réalisé. Résultats Les méningiomes ont représenté 33,43% des tumeurs intracrâniennes. La moyenne d\'âge au moment du diagnostic était de 43 ans avec des extrêmes de 07 à 72 ans. Le sexe féminin a prédominé avec un sex-ratio de 3/2. Le tableau clinique était dominé par les céphalées. Le délai précédant le diagnostic était d\'environ 22 mois. Les méningiomes de la convexité étaient les plus fréquents (47,36%). Dans la majorité des cas le diamètre tumoral se situait entre 3 cm et 6 cm. L\'exérèse chirurgicale a constitué l\'essentiel du traitement avec une mortalité opératoire de 12,63%. Les méningiomes usuels de type méningothélial ont prédominé (55,78%). Conclusion Les méningiomes ont représenté les plus fréquents des tumeurs intracrâniennes en milieu ivoirien. Des études ultérieures africaines épidémiologiques permettront de le vérifier. Les méningiomes ont été diagnostiqués chez des patients relativement plus jeunes (43 ans) que ceux des pays occidentaux (58 ans). Depuis l\'avènement du scanner des services de neurochirurgie et de neuropathologie, les méningiomes ne posent moins de problème de diagnostic. Les unités de recherche sur l\'oncogenèse et sur les thérapeutiques complémentaires à la chirurgie sont encore inexistantes Keywords: intracranial Meningioma / cerebral Tumor / Abidjan.African Journal of Neurological Sciences Vol. 27 (1) 2008: pp. 31-3

Halogenation of a twisted non-polar π-system as a tool to modulate phosphorescence at room temperature

Halogenation of a twisted three-fold symmetric hydrocarbon with F, Cl or Br leads to strong modulation of triplet–triplet annihilation and dual phosphorescence, one thermally activated and the other very persistent and visible by eye, with different relative contributions depending on the halide. The room temperature phosphorescence is highly unusual given the absence of lone-pair-contributing heteroatoms. The interplay between the spin–orbit coupling matrix elements and the spatial configuration of the triplet state induces efficient intersystem crossing and thus room temperature phosphorescence even without relying on heteroatomic electron lone pairs. A ninefold increase of the ISC rate after introduction of three bromine atoms is accompanied by a much higher 34-fold increase of phosphorescence rate

Rational design of an unusual 2D-MOF based on Cu(I) and 4-hydroxypyrimidine-5-carbonitrile as linker with conductive capabilities: a theoretical approach based on high-pressure XRD

Herein, we present, for the first time, a 2D-MOF based on copper and 4-hydroxypyrimidine-5-carbonitrile as the linker. Each MOF layer is perfectly flat and neutral, as is the case for graphene. High pressure X-ray diffraction measurements reveal that this layered structure can be modulated between 3.01 to 2.78 Å interlayer separation, with an evident piezochromism and varying conductive properties. An analysis of the band structure indicates that this material is conductive along different directions depending on the application of pressure or H doping. These results pave the way for the development of novel layered materials with tunable and efficient properties for pressure-based sensors.European Union (EU) 604391Swiss National Science Foundation (SNSF) 200020_162861Spanish Government CEX2018-000805-M CTQ2015-69163-CO2R1 PGC2018-102052-B-C21 PGC2018-102052-A-C22 PGC2018102047-B-I00 FIS2016-80434-P PID2019-109539GB-C43Junta de Andalucia FQM-394Comunidad Autonoma de Madrid through the Nanomag COST-CM Program S2018/NMT-4321University of SevilleNational Council for Scientific and Technological Development (CNPq) 405107/2017-

Helicenes from Diarylmaleimides

Perkin condensations of arylglyoxylic acids with arylacetic acids, followed by the addition of alkylamine, yield diarylmaleimides in a one-pot procedure. The arylglyoxylic acids are obtained by arene acylation with ClCOCO2Et and reduced with NaI and hypophosphorous acid to the arylacetic acids. With 2,7-di-tert-butyl-pyren-4-yl or chrysen-6-yl as the aryl, photocyclodehydrogenation of the diarylmaleimides yields substituted helicenes which can be reduced to stable anions. The helicenes combine bathochromically shifted absorption with hypsochromically shifted fluorescence with respect to their precursors

Palladium-catalyzed multicomponent synthesis of 2-aryl-2-imidazolines from aryl halides and diamines

An efficient palladium-catalyzed three-component reaction that combines aryl halides, isocyanides, and diamines provides access to 2-aryl-2-imidazolines in yields up to 96%. Through variation of the diamine component, the reaction can be extended to the synthesis of 2-aryl-1H-benzimidazoles and 2-aryl-1,4,5,6-tetrahydropyrimidines