Academic underachievement in Cuban university students: a cognitive perspective in the problem solving context

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Metallacycle-Catalyzed S_NAr Reaction in Water: Supramolecular Inhibition by Means of Host–Guest Complexation

The performance of a Pt^II diazapyrenium-based metallacycle as a reusable substoichiometric catalyst for the S_NAr reaction between halodinitrobenzenes and sodium azide at rt in aqueous media is reported. The results suggest that the catalytic effect is promoted by the association of the azide to the diazapyrenium cationic subunits of the catalyst. The findings demonstrate that the formation of an inclusion complex between pyrene and the metallacycle has a regulatory effect over the system, resulting in allosteric-like inhibition of the S_NAr reaction

Na–Vacancy and Charge Ordering in Na_≈2/3FePO₄

NaFePO₄ is known as a promising intercalation cathode material for sodium-ion batteries. During the electrochemical reaction, an intermediate phase forms with a composition close to Na_≈2/3­FePO₄, whose crystal structure is defined with a supercell that results from both Na/vacancy and charge ordering. In this work, we present a detailed study of this superstructure through synchrotron powder X-ray diffraction and electron microscopy studies

Obesity-Dependent Metabolic Signatures Associated with Nonalcoholic Fatty Liver Disease Progression

Our understanding of the mechanisms by which nonalcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH) is still very limited. Despite the growing number of studies linking the disease with altered serum metabolite levels, an obstacle to the development of metabolome-based NAFLD predictors has been the lack of large cohort data from biopsy-proven patients matched for key metabolic features such as obesity. We studied 467 biopsied individuals with normal liver histology (<i>n</i> = 90) or diagnosed with NAFLD (steatosis, <i>n</i> = 246; NASH, <i>n</i> = 131), randomly divided into estimation (80% of all patients) and validation (20% of all patients) groups. Qualitative determinations of 540 serum metabolite variables were performed using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC–MS). The metabolic profile was dependent on patient body-mass index (BMI), suggesting that the NAFLD pathogenesis mechanism may be quite different depending on an individual’s level of obesity. A BMI-stratified multivariate model based on the NAFLD serum metabolic profile was used to separate patients with and without NASH. The area under the receiver operating characteristic curve was 0.87 in the estimation and 0.85 in the validation group. The cutoff (0.54) corresponding to maximum average diagnostic accuracy (0.82) predicted NASH with a sensitivity of 0.71 and a specificity of 0.92 (negative/positive predictive values = 0.82/0.84). The present data, indicating that a BMI-dependent serum metabolic profile may be able to reliably distinguish NASH from steatosis patients, have significant implications for the development of NASH biomarkers and potential novel targets for therapeutic intervention