Search

Patients with drug resistant epilepsy are potential candidates for surgery. The pre surgical study of these patients involves a multidisciplinary approach.We included patients who had been submitted to EEG video monitoring in our centre (a tertiary university hospital) between April 1995 and May 2000. The evaluation protocol included magnetic resonance (MR) brain scan (according to a specific protocol), neuropsychological and psychiatric evaluation, and ictal/interictal SPECT, when possible. Patients who underwent surgery were followed up at regular intervals until at least two years after surgery.Of the 299 patients with EEG video monitoring, 87 had been submitted to surgery up to June 2000. Nine of these patients required invasive subdural studies or studies of the foramen ovale using electrodes. Of the patients who underwent surgery, 44.8% had sclerosis of the hippocampus in the MR and in 10% it was found to be normal. The results of pathological anatomy revealed: 49.3% with sclerosis of the hippocampus, 15.1% with benign tumours, 13.7% with gliosis, 4.1% heterotopias and 4.1% cavernomas. Just one patient has been submitted to surgery again because of badly controlled seizures. Eight patients have presented post surgical complications (four with permanent morbidity). Of the 73 patients who were followed up for at least a year, 83.6% are in Engel class I, 9.6% in class II, 2.7% in class III and 4.1% in class IV. Among patients who underwent a temporal resection, 88.7% were in class I and 0% in class IV.Epilepsy surgery, in selected patients, has a very low morbidity/mortality rate and the chances that seizures will disappear or greatly improve are high.

Natural and anthropogenic gas radionuclides such as radon, xenon, hydrogen and krypton isotopes must be monitored to be managed as pathogenic agents, radioactive diagnostic agents or nuclear activity indicators. State-of-the-art detectors based on liquid scintillators suffer from laborious preparation and limited solubility for gases, which affect the accuracy of the measurements. The actual challenge is to find solid scintillating materials simultaneously capable of concentrating radioactive gases and efficiently producing visible light revealed with high sensitivity. The high porosity, combined with the use of scintillating building blocks in metal–organic frameworks (MOFs), offers the possibility to satisfy these requisites. We demonstrate the capability of a hafnium-based MOF incorporating dicarboxy-9,10-diphenylanthracene as a scintillating conjugated ligand to detect gas radionuclides. Metal–organic frameworks show fast scintillation, a fluorescence yield of ∼40%, and accessible porosity suitable for hosting noble gas atoms and ions. Adsorption and detection of 85Kr, 222Rn and 3H radionuclides are explored through a newly developed device that is based on a time coincidence technique. Metal–organic framework crystalline powder demonstrated an improved sensitivity, showing a linear response down to a radioactivity value below 1 kBq m−3 for 85Kr, which outperforms commercial devices. These results support the possible use of scintillating porous MOFs to fabricate sensitive detectors of natural and anthropogenic radionuclides.

Achieving sophisticated juxtaposition of geared molecular rotors with negligible energy-requirements in solids enables fast yet controllable and correlated rotary motion to construct switches and motors. Our endeavor was to realize multiple rotors operating in a MOF architecture capable of supporting fast motional regimes, even at extremely cold temperatures. Two distinct ligands, 4,4′-bipyridine (bipy) and bicyclo[1.1.1]pentanedicarboxylate (BCP), coordinated to Zn clusters fabricated a pillar-and-layer 3D array of orthogonal rotors. Variable temperature XRD, 2H solid-echo, and 1H T1 relaxation NMR, collected down to a temperature of 2 K revealed the hyperfast mobility of BCP and an unprecedented cascade mechanism modulated by distinct energy barriers starting from values as low as 100 J mol–1 (24 cal mol–1), a real benchmark for complex arrays of rotors. These rotors explored multiple configurations of conrotary and disrotary relationships, switched on and off by thermal energy, a scenario supported by DFT modeling. Furthermore, the collective bipy-ring rotation was concerted with the framework, which underwent controllable swinging between two arrangements in a dynamical structure. A second way to manipulate rotors by external stimuli was the use of CO2, which diffused through the open pores, dramatically changing the global rotation mechanism. Collectively, the intriguing gymnastics of multiple rotors, devised cooperatively and integrated into the same framework, gave the opportunity to engineer hypermobile rotors (107 Hz at 4 K) in machine-like double ligand MOF crystals.

An anionic mechanism is used to create polymers and copolymers as confined to, or anchored to, high-surface-area porous nanoparticles. Linear polymers with soft and glassy chains, such as polyisoprene and polymethylmethacrylate, were produced by confined anionic polymerization in 3D networks of porous aromatic frameworks. Alternatively, multiple anions were generated on the designed frameworks which bear removal protons at selected positions, and initiate chain propagation, resulting in chains covalently connected to the 3D network. Such growth can continue outside the pores to produce polymer-matrix nanoparticles coated with anchored chains. Sequential reactions were promoted by the living character of this anionic propagation, yielding nanoparticles that were covered by a second polymer anchored by anionic block copolymerization. The intimacy of the matrix and the grown-in polymers was demonstrated by magnetization transfer across the interfaces in 2D 1 H-13 C-HETCOR NMR spectra.

The solid state is typically not well suited to sustaining fast molecular motion, but in recent years a variety of molecular machines, switches and rotors have been successfully engineered within porous crystals and on surfaces. Here we show a fast-rotating molecular rotor within the bicyclopentane–dicarboxylate struts of a zinc-based metal–organic framework—the carboxylate groups anchored to the metal clusters act as an axle while the bicyclic unit is free to rotate. The three-fold bipyramidal symmetry of the rotator conflicts with the four-fold symmetry of the struts within the cubic crystal cell of the zinc metal–organic framework. This frustrates the formation of stable conformations, allowing for the continuous, unidirectional, hyperfast rotation of the bicyclic units with an energy barrier of 6.2 cal mol−1 and a high frequency persistent for several turns even at very low temperatures (1010 Hz below 2 K). Using zirconium instead of zinc led to a different metal cluster–carboxylate coordination arrangement in the resulting metal–organic framework, and much slower rotation of the bicyclic units. Molecular rotors have been engineered within the bicyclopentane–dicarboxylate struts of a metal–organic framework—the bicyclic unit is the rotator and the carboxylate groups serve as the stator. In a zinc-based metal–organic framework, the crossed conformation of the strut–metal nodes enables fast rotation of the bicyclic moiety, but in the corresponding zirconium metal–organic framework a change in the conformation results in much slower rotation.

The realization of tunable and functionalized MOFs is a winning strategy for CO2 capture. Here we report on a series of robust Fe-MOFs with triangular channels constructed by rod-like fluorinated pyrazolate ligands, comprising an increasing number of fluorine atoms on the central p-phenylene core (F = 1, 2, and 4). This yielded a series of isoreticular frameworks, engineered with orientational flexibility of the fluorinated aryl rings pivoted on ethynyl groups with an sp2–sp soft rotary barrier, providing a stable axel, which supported reorientable C–F dipoles. A combined approach, including powder X-ray diffraction, multinuclear solid-state NMR (2D 1H–13C, 19F, hyperpolarized 129Xe NMR and distance measurements by paramagnetic shift), gas-adsorption and microcalorimetry, enabled the exhaustive description of the fluorinated ring arrangement and the organization of functionalized sites for accommodating CO2. In the tetrafluoro-aryl-derivative MOF, protrusion of perfluorinated rings towards the channel space plays a major role in CO2 capture. Partially fluorinated aryl rings of mono- and di-fluoro MOFs turn to retract into the channel-walls to form continuous ribbons of inter-strut supramolecular interactions, contributing to the robustness of the overall architecture. Detailed computational models obtained using GCMC and DFT of CO2 diffusion and interactions in MOFs showed how the gas molecules approach the channel walls. The highly occupied sites are aligned at the corners of the triangular channels, wherein fluorine atoms participate in host–CO2 interactions. A CO2–matrix adsorption enthalpy of 33 kJ mol−1, suitable for capture/delivery cycles, was accurately measured in situ by simultaneous acquisition of microcalorimetric and volumetric-isotherm data. Thus, the designed advantages of rotationally flexible fluorinated moieties were successfully explored.

Porous aromatic frameworks (PAFs) were engineered to generate solid-state upconverting materials that emit higher energy photons under a suitable light stimulus [1]. Fluorescent PAFs were generated by the inclusion of diphenylanthracene moieties in a low-density 3D porous frameworks that maintained the optical properties of the emitting chromophores in the solid-state. Upon inclusion of a suitable sensitizer (a metallo-porphyrin) inside the nanometer-sized pores, the copolymer displayed sensitized photon upconversion with a quantum yield as high as 15%, a record value for solid-state materials. Moreover, it was possible to tether the sensitizer to the porous matrix through a stable covalent bond, generating self-standing upconverting nanoparticles that can be possibly applied in photovoltaics and bio-imaging. PAFs can also be engineered as light-responsive materials. The co-polymerization of a photoswitch with tetraphenylmethane generated porous networks that provided the free volume for the photoisomerization of the overcrowded alkene [2]. Under UV light irradiation, the quantitative photoisomerization led to structural changes and modulated the CO2 adsorptive properties of the material. The process is reversible by irradiation or heating leading to a cyclable material.

Hybrid mesoporous organosilica exhibiting crystal-like order in the walls provided an ideal channel reaction vessel for the confined polymerization of acrylonitrile (PAN). The resulting high-molecular-mass PAN fills the channels at high yield and forms an ordered nanostructure of polymer nanobundles enclosed into the hybrid matrix. The in situ thermal transformation of PAN into rigid polyconjugated and, eventually, into condensed polyaromatic carbon nanofibers, retains the periodic architecture. Simultaneously, the matrix evolves showing the fusion of the p-phenylene rings and the cleavage of carbon-silicon bonds: this gives rise to graphitic-carbon/silica nanocomposites containing hyper-oxydrylated silica nanophases. Interestingly, the 3D hexagonal mesostructure survives in the carbonaceous material. The exploitation of porous materials of high capacity and a hybrid nature, for polymerization in the confined state, followed by high temperature treatments, allowed us to achieve unique and precisely fabricated nanostructures, thus paving the way for the construction of fine-tuned electronic and light-harvesting materials.