Prebiotic supplementation does not affect reading and cognitive performance in children: A randomised placebo-controlled study

Based on the emerging interest in the effects of gut microbiota on cognition, this proof-of-concept study assessed how children aged 7 to 9 with low reading scores responded to the ingestion of a 3-month prebiotic supplement versus a placebo. As a secondary aim, the effects of the prebiotic on cognition, sleep, behaviour, mood, anxiety, and cortisol were assessed. In this sample, the prebiotic did not affect any of the outcome measures

Prebiotic supplementation does not affect reading and cognitive performance in children: A randomised placebo-controlled study

Based on the emerging interest in the effects of gut microbiota on cognition, this proof-of-concept study assessed how children aged 7 to 9 with low reading scores responded to the ingestion of a 3-month prebiotic supplement versus a placebo. As a secondary aim, the effects of the prebiotic on cognition, sleep, behaviour, mood, anxiety, and cortisol were assessed. In this sample, the prebiotic did not affect any of the outcome measures

Synthesis Of Azo Carbonate Monomers And Biocompatibility Study Of Poly(azo-carbonate-urethane)s

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The present work describes the synthesis of azo carbonate monomers by a clean carbonylation synthetic route using di-methylcarbonate. The kinetics study showed a conversion of similar to 98% to bis-carbonates after only six minutes of reaction using triazabicyclo[4.4.0]dec-5-ene (TBD) as the catalyst. The preparation of azo-carbonates by means of coupling aryldiazonium salts with bis-carbonate was performed. The reactivity of azo-carbonate monomers was tested in the polycondensation reaction with an aminoalcohol using TBD as a catalyst for the formation of non-isocyanate poly(azo-carbonate-urethane)s PCU 1 and PCU 2. The copolymers' structures were confirmed by FT-IR, NMR and MALDI experiments, which allow us to determine the different terminal groups of the polymer chains formed. The molecular weights and the molecular weight distribution of PCU 1 and PCU 2 were determined by size-exclusion chromatography (SEC) experiments and thermal stabilities were also studied by TG analysis. The biocompatible properties of monomers 4 and 6 and polymers PCU 1 and PCU 2 were investigated by liver, kidney and colon histological analyses.6837998779997FAPESP [2013/24487-6]CNPqCAPESFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Synthesis, Radical Reactivity, and Thermochemistry of Monomeric Cu(II) Alkoxide Complexes Relevant to Cu/Radical Alcohol Oxidation Catalysis

Two new monomeric Cu­(II) alkoxide complexes were prepared and fully characterized as models for intermediates in copper/radical mediated alcohol oxidation catalysis: Tp^<i>t</i>BuRCu^IIOCH₂CF₃ with Tp^<i>t</i>Bu = hydro-tris­(3-<i>tert</i>-butyl-pyrazol-1-yl)­borate <b>1</b> or Tp^<i>t</i>BuMe = hydro-tris­(3-<i>tert</i>-butyl-5-methyl-pyrazol-1-yl)­borate <b>2</b>. These complexes were made as models for potential intermediates in enzymatic and synthetic catalytic cycles for alcohol oxidation. However, the alkoxide ligands are not readily oxidized by loss of H; instead, these complexes were found to be hydrogen atom <i>acceptors</i>. They oxidize the hydroxylamine TEMPOH, 2,4,6-tri-<i>t</i>-butylphenol, and 1,4-cyclohexadiene to the nitroxyl radical, phenoxyl radical, and benzene, with formation of HOCH₂CF₃ (TFE) and the Cu­(I) complexes Tp^<i>t</i>BuRCu^I-MeCN in dichloromethane/1% MeCN or 1/2 [Tp^<i>t</i>BuRCu^I]₂ in toluene. On the basis of thermodynamics and kinetics arguments, these reactions likely proceed through concerted proton–electron transfer mechanisms. Thermochemical analyses give lower limits for the “effective bond dissociation free energies (BDFE)” of the O–H bonds in 1/2­[Tp^<i>t</i>BuRCu^I]₂ + TFE and upper limits for the free energies associated with alkoxide oxidations via hydrogen atom transfer (<i>effective</i> alkoxide α-C–H BDFEs). These values are summations of the free energies of multiple chemical steps, which include the energetically favorable formation of 1/2­[Tp^<i>t</i>BuRCu^I]₂. The <i>effective</i> alkoxide α-C–H bonds are very weak, BDFE ≤ 38 ± 4 kcal mol^–1 for <b>1</b> and ≤44 ± 5 kcal mol^–1 for <b>2</b> (gas-phase estimates), because C–H homolysis is thermodynamically coupled to one electron transfer to Cu­(II) as well as the favorable formation of the 1/2­[Tp^<i>t</i>BuRCu^I]₂ dimer. Treating <b>1</b> with the H atom acceptor ^<i>t</i>Bu₃ArO^• did not result in the expected alkoxide oxidation to an aldehyde, but rather net 2,2,2-trifluoroethoxyl radical transfer occurred to generate an unusual 2-substituted dienone–ether product. Treating <b>2</b> with ^<i>t</i>Bu₃ArO^• gives no reaction, despite evidence that overall ligand oxidation and formation of 1/2­[Tp^<i>t</i>BuMeCu^I]₂ is significantly exoergic. The origin of this lack of reactivity may be due to insufficient weakening of the alcohol α-C–H bond upon complexation to copper

Synthesis, Radical Reactivity, and Thermochemistry of Monomeric Cu(II) Alkoxide Complexes Relevant to Cu/Radical Alcohol Oxidation Catalysis

Two new monomeric Cu­(II) alkoxide complexes were prepared and fully characterized as models for intermediates in copper/radical mediated alcohol oxidation catalysis: Tp^<i>t</i>BuRCu^IIOCH₂CF₃ with Tp^<i>t</i>Bu = hydro-tris­(3-<i>tert</i>-butyl-pyrazol-1-yl)­borate <b>1</b> or Tp^<i>t</i>BuMe = hydro-tris­(3-<i>tert</i>-butyl-5-methyl-pyrazol-1-yl)­borate <b>2</b>. These complexes were made as models for potential intermediates in enzymatic and synthetic catalytic cycles for alcohol oxidation. However, the alkoxide ligands are not readily oxidized by loss of H; instead, these complexes were found to be hydrogen atom <i>acceptors</i>. They oxidize the hydroxylamine TEMPOH, 2,4,6-tri-<i>t</i>-butylphenol, and 1,4-cyclohexadiene to the nitroxyl radical, phenoxyl radical, and benzene, with formation of HOCH₂CF₃ (TFE) and the Cu­(I) complexes Tp^<i>t</i>BuRCu^I-MeCN in dichloromethane/1% MeCN or 1/2 [Tp^<i>t</i>BuRCu^I]₂ in toluene. On the basis of thermodynamics and kinetics arguments, these reactions likely proceed through concerted proton–electron transfer mechanisms. Thermochemical analyses give lower limits for the “effective bond dissociation free energies (BDFE)” of the O–H bonds in 1/2­[Tp^<i>t</i>BuRCu^I]₂ + TFE and upper limits for the free energies associated with alkoxide oxidations via hydrogen atom transfer (<i>effective</i> alkoxide α-C–H BDFEs). These values are summations of the free energies of multiple chemical steps, which include the energetically favorable formation of 1/2­[Tp^<i>t</i>BuRCu^I]₂. The <i>effective</i> alkoxide α-C–H bonds are very weak, BDFE ≤ 38 ± 4 kcal mol^–1 for <b>1</b> and ≤44 ± 5 kcal mol^–1 for <b>2</b> (gas-phase estimates), because C–H homolysis is thermodynamically coupled to one electron transfer to Cu­(II) as well as the favorable formation of the 1/2­[Tp^<i>t</i>BuRCu^I]₂ dimer. Treating <b>1</b> with the H atom acceptor ^<i>t</i>Bu₃ArO^• did not result in the expected alkoxide oxidation to an aldehyde, but rather net 2,2,2-trifluoroethoxyl radical transfer occurred to generate an unusual 2-substituted dienone–ether product. Treating <b>2</b> with ^<i>t</i>Bu₃ArO^• gives no reaction, despite evidence that overall ligand oxidation and formation of 1/2­[Tp^<i>t</i>BuMeCu^I]₂ is significantly exoergic. The origin of this lack of reactivity may be due to insufficient weakening of the alcohol α-C–H bond upon complexation to copper

Synthesis, Radical Reactivity, and Thermochemistry of Monomeric Cu(II) Alkoxide Complexes Relevant to Cu/Radical Alcohol Oxidation Catalysis

Two new monomeric Cu­(II) alkoxide complexes were prepared and fully characterized as models for intermediates in copper/radical mediated alcohol oxidation catalysis: Tp^<i>t</i>BuRCu^IIOCH₂CF₃ with Tp^<i>t</i>Bu = hydro-tris­(3-<i>tert</i>-butyl-pyrazol-1-yl)­borate <b>1</b> or Tp^<i>t</i>BuMe = hydro-tris­(3-<i>tert</i>-butyl-5-methyl-pyrazol-1-yl)­borate <b>2</b>. These complexes were made as models for potential intermediates in enzymatic and synthetic catalytic cycles for alcohol oxidation. However, the alkoxide ligands are not readily oxidized by loss of H; instead, these complexes were found to be hydrogen atom <i>acceptors</i>. They oxidize the hydroxylamine TEMPOH, 2,4,6-tri-<i>t</i>-butylphenol, and 1,4-cyclohexadiene to the nitroxyl radical, phenoxyl radical, and benzene, with formation of HOCH₂CF₃ (TFE) and the Cu­(I) complexes Tp^<i>t</i>BuRCu^I-MeCN in dichloromethane/1% MeCN or 1/2 [Tp^<i>t</i>BuRCu^I]₂ in toluene. On the basis of thermodynamics and kinetics arguments, these reactions likely proceed through concerted proton–electron transfer mechanisms. Thermochemical analyses give lower limits for the “effective bond dissociation free energies (BDFE)” of the O–H bonds in 1/2­[Tp^<i>t</i>BuRCu^I]₂ + TFE and upper limits for the free energies associated with alkoxide oxidations via hydrogen atom transfer (<i>effective</i> alkoxide α-C–H BDFEs). These values are summations of the free energies of multiple chemical steps, which include the energetically favorable formation of 1/2­[Tp^<i>t</i>BuRCu^I]₂. The <i>effective</i> alkoxide α-C–H bonds are very weak, BDFE ≤ 38 ± 4 kcal mol^–1 for <b>1</b> and ≤44 ± 5 kcal mol^–1 for <b>2</b> (gas-phase estimates), because C–H homolysis is thermodynamically coupled to one electron transfer to Cu­(II) as well as the favorable formation of the 1/2­[Tp^<i>t</i>BuRCu^I]₂ dimer. Treating <b>1</b> with the H atom acceptor ^<i>t</i>Bu₃ArO^• did not result in the expected alkoxide oxidation to an aldehyde, but rather net 2,2,2-trifluoroethoxyl radical transfer occurred to generate an unusual 2-substituted dienone–ether product. Treating <b>2</b> with ^<i>t</i>Bu₃ArO^• gives no reaction, despite evidence that overall ligand oxidation and formation of 1/2­[Tp^<i>t</i>BuMeCu^I]₂ is significantly exoergic. The origin of this lack of reactivity may be due to insufficient weakening of the alcohol α-C–H bond upon complexation to copper