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Maple Syrup Urine Disease (MSUD) is an autosomal recessive inherited disorder, caused by a deficiency on branched chain α-ketoacid dehydrogenase complex activity, resulting in accumulation of branched-chain amino acids (BCAA) (e.g. leucine). The treatment of MSDU patients increases survival time and quality of life. Thus, nowadays there are a crescent number of adolescents and adults with MSUD. Relevant studies have been reported behavioral alterations in these patients, i.e. high risk of chronic neuropsychiatric problems, such as attention deficit disorder, depression and anxiety. Moreover, MSUD is associated to neurotransmitters deficiency. Herein, we aimed to investigate whether the toxicity of leucine is associated to anxiety-like behavioral, using zebrafish acutely exposed to leucine as experimental model of MSUD. In addition, we evaluated the effects of high levels of leucine in the acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities, components of cholinergic neurotransmission system. Young zebrafish were exposed to 2 mM and 5 mM concentration of leucine for 24 h. After that, the animals were submitted to the Novel Tank test, having the brain collected to enzymatic determination. The exposure to both concentrations of leucine caused behavioral and brain cholinergic activity alterations in young zebrafish, indicating an anxiety-like behavior and cholinergic dysfunction. Therefore, this animal could be considered a promising organism to study the BCAA neurotoxic effects, which could help to a better comprehension of the behavioral and neurochemical alterations present in patients with MSUD.

Using atomistic simulations based on lattice energy minimization, rare earth doping and co‐doping in Li2SrSiO4 (LSSO) are investigated in terms of energetics. The doping effects are determined by the calculation of atomistic energetics, using potential parameters developed from an empirical potential by fitting. The potential parameters obtained in this way allowed us to reproduce the structural parameters, and the results showed good agreement with the experimental data. The results of these calculations indicate that the Li Frenkel and Li2O Schottky defects are the most favorable intrinsic defects, and also reveal that RE3+ = Ce, Pr, Sm, Eu, Dy, Er and RE2+ = Eu ions are most energetically favorable for incorporation at the Sr site. Charge compensation by VLi′ vacancy defects is the most probable route for RE3+ ion incorporation. The reduction–doping processes (Eu reduction) in a H2 reducing atmosphere were considered, and the effects of co‐doping on Eu reduction were also investigated.

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