Mechanochemical preparation of a modified NiAl2O4 structure.

Mechanochemical synthesis routes offer a sustainable, simple method for preparing materials. In this work, NiAl2O4 was synthesised by a mechanically activated method using a high-energy planetary mill and a calcination step. This study aims to identify the effect of different milling energies on the phases, chemical environments and surface composition of the material. In addition, it explores the thermal impact on the decomposition and structure of the materials. The materials were characterised by X-ray phosphorescence (XPS), solid-state UV-VIS (SS-UV-VIS), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), high-resolution transmission electron microscopy (HR-TEM) and thermal gravimetry differential scanning calorimetry (TGA-DSC). A co-precipitated material is used as a reference along with the ground reagents which were used as a baseline. From this in-depth analysis of the material, a good understanding of the disordered partially inverse spinel structure is provided. This study has found that with calcination temperatures of 750 °C and 900 °C a mixed NiAl2O4 : NiO phase is produced with a Ni enriched surface. The surface is found to be relatively stable with the increase from 750 °C to 900 °C.

The electronic structure, surface properties, and in situ N2O decomposition of mechanochemically synthesised LaMnO3.

The use of mechanochemistry to prepare catalytic materials is of significant interest; it offers an environmentally beneficial, solvent-free, route and produces highly complex structures of mixed amorphous and crystalline phases. This study reports on the effect of milling atmosphere, either air or argon, on mechanochemically prepared LaMnO3 and the catalytic performance towards N2O decomposition (deN2O). In this work, high energy resolution fluorescence detection (HERFD), X-ray absorption near edge structure (XANES), X-ray emission, and X-ray photoelectron spectroscopy (XPS) have been used to probe the electronic structural properties of the mechanochemically prepared materials. Moreover, in situ studies using near ambient pressure (NAP)-XPS, to follow the materials during catalysis, and high pressure energy dispersive EXAFS studies, to mimic the preparation conditions, have also been performed. The studies show that there are clear differences between the air and argon milled samples, with the most pronounced changes observed using NAP-XPS. The XPS results find increased levels of active adsorbed oxygen species, linked to the presence of surface oxide vacancies, for the sample prepared in argon. Furthermore, the argon milled LaMnO3 shows improved catalytic activity towards deN2O at lower temperatures compared to the air milled and sol-gel synthesised LaMnO3. Assessing this improved catalytic behaviour during deN2O of argon milled LaMnO3 by in situ NAP-XPS suggests increased interaction of N2O at room temperature within the O 1s region. This study further demonstrates the complexity of mechanochemically prepared materials and through careful choice of characterisation methods how their properties can be understood.

Effectiveness and safety of perampanel as early add-on treatment in patients with epilepsy and focal seizures in the routine clinical practice: Spain prospective study (PERADON).

OBJECTIVE: Perampanel (PER) has been shown to be effective as an adjunctive therapy for controlling refractory focal-onset seizures (FOS). However, the information as early add-on for the treatment of FOS in the clinical practice is still scarce and must be further assessed. METHODS: An observational prospective study was conducted to evaluate the effectiveness of early add-on PER, assessed as 50% responders (seizure frequency reduced by at least 50% during the last 3 months as compared with baseline) rate at 6 and 12 months, in patients with FOS in the routine clinical practice of Spain. RESULTS: One hundred and thirteen patients (mean age: 40.3 years, 51.3% male) with FOS received PER as early add-on (1st add-on: 37.2% and 2nd: 62.8%) for a mean exposure of 11 months (mean PER dose: 6.3 mg/day at month 12). At 6 months, 50.4% and 20.4% of the patients were responders and seizure-free (respectively) relative to baseline (3 months prior to PER initiation), and at 12 months, 68.1% and 26.5% of the patients were responders and seizure-free (respectively), relative to baseline (3 months prior to PER initiation). The retention rate at 6 and 12 months was 83.2% and 80.5%, respectively. The percentage of seizure-free patients at 12 months was significantly (p = 0.033) higher when PER was added as first vs. second add-on. The number of concomitant antiepileptic drugs (AEDs) was significantly reduced from baseline to 6 and 12 months (p = 0.001). Treatment was simplified in 23.9% of patients at the end of the observation period. Drug-related adverse events (AEs), most mild or moderate, were reported in 30.1% of patients, with irritability (8%) and dizziness (7.1%) as the most frequent ones. CONCLUSIONS: This is the first observational, prospective study to evaluate efficacy and safety of early adjunctive treatment with PER in patients with focal epilepsy at 12 months. Perampanel demonstrated a good efficacy and safety profile when used at a median dose of 6 mg/day, regardless of the combination with other AEDs. Adverse events were mild or moderate, with dizziness being the most frequent one.

Understanding the mechanochemical synthesis of the perovskite LaMnO3 and its catalytic behaviour.

Mechanochemistry offers a solventless, 'waste free' route to preparing metal oxide catalysts, however, there is limited information on the chemical steps involved. In this work, the perovskite LaMnO3 has been successfully synthesized via mechanochemistry from metal oxide powders, La2O3 and Mn2O3, at room temperature, using a planetary ball mill. Separate ex situ'time slices' were taken during the milling procedure to provide insights into the underlying chemistry. The crystalline material was assessed using XRD, which identified 100% perovskite phase after 3 h of milling. Conversely, characterization by X-ray absorption spectroscopy (XAS) at both the Mn K-edge and La L3-edge provides a very different picture. The XAS data shows that there are significant structural alterations as early as 30 min of milling, with the La precursor dispersed over Mn2O3. Increasing milling time then allows for mechanical activation of both precursors and the formation of powdered LaMnO3, with no calcination step required. The XAS highlights that there is a significant amount of amorphous, oxygen deficient, content even when XRD has identified 100% perovskite phase. The samples were tested for the decomposition of the environmental pollutant N2O; at a milling time of 3 h, the LaMnO3 catalyst displays a much early onset production of N2 compared to a traditional sol-gel synthesized LaMnO3, resulting from increased oxygen deficiency at the surface, confirmed by XPS and STEM-EELS. This is an encouraging sign that mechanochemical routes can be harnessed to provide a sustainable route to preparing mixed metal oxide catalysts with enhanced catalytic performance.