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Objective: Thirty percent of the patients for whom code stroke is activated have stroke mimics, the most common being epilepsy. Our purpose was to evaluate the usefulness of multiparametric CT for differentiating between seizure-related symptoms and vascular events. Material and methods: We conducted a retrospective observational study; data were gathered prospectively during one year. We studied multiparametric CT images of patients admitted following code stroke activation and finally diagnosed with epilepsy. Results: The study included a total of 11 patients; 36% were men and mean age was 74.5 years. Three patients had right hemisphere syndrome, 4 displayed left hemisphere syndrome, and the remaining 4 had isolated aphasia. Maximum time from symptom onset to multiparametric CT study was 8.16 hours. Perfusion CT results were normal in 2 patients. Nine patients showed longer or shorter times to peak (Tmax); cerebral blood volume (CBV) and cerebral blood flow (CBF) maps varied. EEG was performed a maximum of 47.6 hours after symptom onset. Four patients showed findings compatible with status epilepticus, 2 displayed focal epileptiform activity, and 5 showed post-ictal slowing ipsilateral to perfusion CT abnormalities. Conclusion: The most sensitive parameter for differentiating between stroke and epilepsy in our series was increased time to peak in multilobar cortical locations in the absence of large-vessel occlusion and basal ganglia involvement. Multiparametric CT is a fast, readily available, and useful tool for the differential diagnosis of acute-onset neurological signs of epileptic origin in patients initially attended after code stroke activation. Resumen: Objetivo: Tras la activación del código ictus, hasta un 30% de los pacientes presentan cuadros imitadores del ictus, siendo la epilepsia el más frecuente. Evaluamos la utilidad de la TC cerebral multiparamétrica para la diferenciación de los déficit de origen comicial versus vascular. Material y métodos: Estudio observacional retrospectivo con recogida prospectiva de datos. Se revisan imágenes de TC multiparamétrica de pacientes atendidos como código ictus durante un año que finalmente fueron diagnosticados de etiología comicial. Resultados: N = 11 (varones 36%, edad media 74,5 años). Tres pacientes presentaban focalidad neurológica derecha, 4 focalidad izquierda y 4 afasia aislada. El tiempo máximo desde el inicio de la clínica hasta la realización de la TC multiparamétrica fue de 8,16 h. La TC perfusión fue normal en 2 pacientes. Nueve pacientes mostraron alargamiento/acortamiento del tiempo al pico (Tmáx), siendo los mapas de flujo y volumen variables. El electroencefalograma se realizó con un tiempo máximo de evolución desde el inicio de la clínica de 47,6 h. Cuatro registros mostraron hallazgos compatibles con estatus epiléptico, 2 actividad epileptiforme focal y los 5 restantes lentificación poscrítica ipsolateral a las anomalías de la TC perfusión. Conclusión: El alargamiento del tiempo al pico en una distribución cortical multilobar en ausencia de oclusión de gran vaso y con respeto de ganglios de la base ha resultado el parámetro más sensible para la diferenciación de estas entidades en nuestra serie. Consideramos que la TC cerebral multiparamétrica es una herramienta rápida, disponible y útil para el diagnóstico diferencial de síntomas neurológicos deficitarios de inicio brusco debidos a etiología comicial que son atendidos como código ictus. Keywords: Stroke mimics, Cerebral perfusion computerised tomography, Multiparametric computerised tomography, Epilepsy, Stroke, Palabras clave: Stroke mimics, Tomografía computarizada perfusión, Tomografía computarizada multiparamétrica, Epilepsia, Ictus

Hysteresis and magnetic relaxation curves were performed on double well potential systems with quantum tunneling possibility via stochastic simulations. Simulation results are compared with experimental ones using the Mn12 single-molecule magnet, allowing us to introduce time dependence in the model. Despite being a simple simulation model, it adequately reproduces the phenomenology of a thermally activated quantum tunneling and can be extended to other systems with different parameters. Assuming competition between the reversal modes, thermal (over) and tunneling (across) the anisotropy barrier, a separation of classical and quantum contributions to relaxation time can be obtained.

Heating efficiency of multifunctional Ag@Fe 3 O 4 brick-like nanoparticles under alternating magnetic field was investigated by means of specific absorption rate (SAR) measurements, and compared with equivalent measurements for plain magnetite and dimer heteroparticles. The samples were synthesized by thermal decomposition reactions and present narrow size polydispersity and high degree of crystallinity. The SAR values are analyzed using the superparamagnetic theory, in which the basic morphology, size and dispersion of sizes play key roles. The results suggest that these novel brick-like nanoparticles are good candidates for hyperthermia applications, displaying heating efficiencies comparable with the most efficient plain nanoparticles.

Teriflunomide is an oral first-line disease modifying treatment (DMT) for patients with relapsing-remitting multiple sclerosis (RRMS). It can take up to two years to achieve systemic clearance of teriflunomide to an acceptable level, but this washout period may be accelerated by administration of cholestyramine. Relapse of multiple sclerosis (MS) during washout of teriflunomide or other first-line DMT is not as common. We report two patients with RRMS who experienced a relapse after the accelerated elimination period (AEP) of teriflunomide and confirmation of negative plasmatic levels (

We review recent studies, experimental and theoretical, of the nonlinear magnetic response of Mn12 single-molecule magnets. Compared with the linear ac susceptibility, which has become the standard tool to ascertain whether a molecular cluster possesses magnetic memory (i.e. whether it behaves as a “single-molecule magnet”), the nonlinear susceptibility provides additional information on the relaxation process at a little cost in terms of experimental time and complexity. The nonlinear dynamic susceptibility depends not only on the relaxation times, as the linear susceptibility does, but also on how sensitive the relaxation process is to external magnetic fields. We show that the presence of spin quantum tunneling, and its strong dependence on external bias that detune the tunneling levels, gives rise to a very large contribution to the nonlinear response of Mn12 clusters. Just like tunneling itself, this “quantum nonlinearity” can be “switched off and on” by external magnetic fields. By studying the orientational dependence of the nonlinear susceptibility, we estimate a bound for the decoherence time due to the coupling to the phonon bath. We find that, for tunneling via thermally activated states of Mn12 acetate, decoherence is not limited by the lifetime of the excited states, but by a much shorter timescale of order 10−11 s.