Oxygen Diffusion and Surface Exchange Coefficients of Porous La0.6Sr0.4Co0.2Fe0.8O3-δ Decorated with Co3O4 Nanoparticles

This work presents a comparative study of the diffusion (Dchem) and surface exchange coefficients (kchem) of porous La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and Co3O4 nanoparticles decorated LSCF electrodes. The study was carried out using the 3DT-EIS method, which combines Electrochemical Impedance Spectroscopy experiments with FIB-SEM tomography data through an adapted Transmission Line - Adler Lane Steele electrochemical model. A reduction of the polarization resistance of about 60% was measured for the Co3O4 decorated LSCF respect to the reference LSCF cathode, in air at 700 °C. The Co3O4 decoration was found to modify the ORR surface reaction limiting mechanism from O2 dissociation to O-ion incorporation, whereas the diffusion coefficient was not modified by the decoration, which represents a surface diffusion process for both electrodes. After the EIS measurements, the Co3O4 particles were almost no longer visible by Field-Emission SEM on the surface of the decorated sample, but signs that these particles play an active role in Sr Segregation were observed by STEM-EDS, in particular by concentrating the segregated SrO in the surroundings of the decorated particles.

Therapeutic Challenge in a Case of Recent Onset Refractory Cluster Seizures

A dilemma exists in context to the timing of surgery in a case presenting with explosive onset seizures secondary to a focal cortical dysplasia (FCD). This case report highlights the challenges faced in the management of a 4-year-old child with recent onset cluster seizures refractory to anti-epileptic drugs. A 4-year-old girl presented with an acute onset of cluster seizures (up to 32 in a day), semiologically characterized by tonic upper limb extension and laughter lasting for few seconds with no response to multiple anti-epileptic drugs. The clinical, electrographic, neuroimaging and interictal positron emission tomography data were concordant and consistent with a left middle frontal gyrus dysplasia which was successfully resected under electrocorticographic guidance. Patient is seizure free at 2 months of follow up. (Engel Class 1). Surgical resection is feasible and potentially more effective in the early phase of clinical presentation of FCD.

A comparative study of promising filter materials for neutron imaging facilities

The effect of sapphire and bismuth single-crystal filters and their combinations on the quality of neutron radiographic images and neutron tomography data has been studied. The parameters of the contrast of the neutron image were analyzed depending on the monocrystalline filters. Neutron transmission spectra were obtained for sapphire and bismuth single crystals. Additionally, the effect of filters on the overall intensity of the thermal neutron beam and the background of gamma-rays was investigated. Based on the obtained data, we assume that a single-crystal sapphire filter can be most effectively used for radiographic and tomographic installations using thermal neutrons.

Role of Radiology Methods in Differential Diagnosis of Fibrous Dysplasia of Base of the Skull

Purpose: Improvement of the differential diagnosis of fibrous dysplasia of the of the base of the skull on the basis of X-ray computed tomography data, taking into account clinical and medical data.Material and methods: The results of examination of 24 patients with lesions of the base of the skull were analyzed. Group 1: 15 patients with fibrous dysplasia, directed to examination with a diagnosis of osteoplastic metastases of the base of the skull. Group 2: 9 patients with metastases to the base of the skull. All patients underwent computer tomography and SPECT/CT.Results: Comparison of clinical and radiological symptoms in patients with metastatic lesions of the base of the skull (group 2) and patients with fibrous dysplasia of the base of the skull (group 1) allows us to state that errors in the differential diagnosis of bone metastases and fibrous dysplasia of the base of the skull in a number of cases are associated with a lack of awareness of radiologists.Conclusion: The presented data will help to improve the diagnosis of fibrous dysplasia of the base of the skull.

Genetic factors affecting dopaminergic deterioration during the premotor stage of Parkinson disease

To estimate dopaminergic dysfunction in patients with Parkinson disease (PD) during the premotor stage and to investigate the effect of genetic factors on the trajectories. Using longitudinal dopamine transporter single-photon emission computed tomography data from 367 sporadic PD (sPD), 72 LRRK2 (G2019S), and 39 GBA (N370S) PD patients in the Parkinson’s Progression Markers Initiative (PPMI) study, we estimated the temporal trajectories of putaminal-specific binding ratios using an integrating function between baseline values and their annual change rates. In order to test reproducibility, we computed another trajectory for sPD using positron emission tomography data of 38 sPD patients at Gangnam Severance Hospital (GSH). Temporal trajectories of sPD were compared between the groups separated by age at onset (AAO) and polygenic load for common PD risk variants, and also compared with genetic PD. sPD patients in both the PPMI and GSH cohorts showed similar onset of dopaminergic degeneration around 10 years before motor onset. Early-onset PD patients exhibited later onset of degeneration and a faster decline in dopaminergic activity during the premotor period than late-onset patients. sPD patients with high polygenic load were associated with earlier onset and slower progression of dopaminergic dysfunction. Compared to the sPD and LRRK2 PD groups, GBA PD patients exhibited faster deterioration of dopaminergic function during the premotor stage. Dopaminergic dysfunction in PD appears to start about 10 years before motor onset. Genetic factors may be contributing to the heterogeneity of dopaminergic deterioration during the premotor stage.