Comparação entre diferentes equações antropométricas e a pletismografia para estimar o percentual de gordura de atletas masculinos de Taekwondo

TCC (Graduação) - Universidade Federal de Santa Catarina. Centro de Desportos. Educação Física - Bacharelado.O Taekwondo é um esporte de combate oriundo da Coréia, atualmente integrao quadro de esportes olímpicos, no qual tem suas lutas divididas por categorias de peso, que possui como principal característica os chutes, estes, que são definidos por fatores físicos e que correspondem a 98% dos gestos do combate. Por ser um esporte intermitente, solicita alta preparação física durante a competição, no qual uma luta tem duração aproximada de 8 min, e pelas mudanças ocorridas nos últimos anos, fez com que a antropometria dos atletas fosse um fator decisivo no resultado de uma luta. Pela falta de um protocolo qualificado, específico e válido para avaliar a composição corporal destes atletas, o presente estudo tem como objetivo verificar quais equações antropométricasapresenta maior correlação quando correlacionado com o método de pletismografia por deslocamento de ar para avaliação dopercentual de gordura de atletas masculinos de Taekwondo. Participaram da pesquisa 11 atletas de Taekwondo com idade entre 16 e 30 anos, que foram avaliados por meio de medidas antropométricas de dobras cutâneas, circunferências e perímetros e pelo método de referência pletismografiapor deslocamento de ar. Posteriormente analisou-se a correlação entre a pletismografia por deslocamento de ar e as equações antropométricas.Das nove equações utilizadas seis não apresentaram diferença significativa (p>0,05) com relação à pletismografiapor deslocamento de ar. Dentre estas, três equações apresentaram grande correlação e duas delas apresentaram correlação muito grande com r=914. Devido as características, Whiterset al. (1987) foi considerada a mais adequada para avaliar o %G de atletas masculinos de Taekwondo

Bridgehead Hydrogen Atoms Are Important: Unusual Electrochemistry and Proton Reduction at Iron Dimers with Ferrocenyl-Substituted Phosphido Bridges

The diphosphido-bridged diiron clusters <i>syn</i>-[{μ_<i>2</i>-P­(CH₂Fc)­H}₂Fe₂(CO)₆] (<b>2a</b>) and <i>anti</i>-/<i>syn</i>-[{μ_<i>2</i>-P­(CH₂Fc)­Me}₂Fe₂(CO)₆] (<b>3</b>), containing covalently linked ferrocenyl (Fc) groups, were synthesized in order to explore the effect of having a redox-active ligand bound to a Fe₂P₂ core as in the covalently linked Fe₄S₄-{μ₂-S­(Cys)}-Fe₂S₂ cofactor of [FeFe]-hydrogenases. The X-ray crystal structure of <b>2a</b> shows an Fe–Fe bond length of 2.630(1) Å and confirms that the two P–H bonds of the bridging 1°-phosphido groups are parallel and are separated by 2.683(2) Å. Cyclic voltammetry and spectroelectrochemistry studies revealed that <b>2a</b>, unusually, undergoes one-electron reduction at −2.18 V (vs Fc⁺/Fc) to give the anion [{μ_<i>2</i>-P­(CH₂Fc)}­{μ_<i>2</i>-P­(CH₂Fc)­H}­Fe₂(CO)₆]^<b>–</b> ([<b>2a</b> – H]^<b>–</b>), which was independently obtained by deprotonation of <b>2a</b> with excess 1,8-diazabicycloundec-7-ene (DBU). The reduction proceeds through the radical anion <b>2a</b>′^{<b>•–</b>} intermediate, which was detected by X-band EPR spectroscopy in situ during electrolysis. The formation of [<b>2a</b> – H]^<b>–</b> from the <b>2a</b>′^{<b>•–</b>} radical formally equates to loss of a hydrogen atom from the bridging P–H group. The result suggests that a new low-energy route for evolution of molecular hydrogen is available in Fe₂E₂ dimers with bridgehead hydrogen atomsi.e. dimers with hydrogen directly bonded to the bridging nonmetal atoms (E = P, S). In contrast to the one-electron reduction behavior of <b>2a</b>, the mixture of dimers <b>3</b> exhibited a two-electron reduction at −2.11 V (vs Fc⁺/Fc) that afforded <b>3</b>^2–. Both dimers catalyze the reduction of protons from <i>p</i>-toluenesulfonic acid, with <b>2a</b> exhibiting higher catalytic currents at lower overpotential

Bridgehead Hydrogen Atoms Are Important: Unusual Electrochemistry and Proton Reduction at Iron Dimers with Ferrocenyl-Substituted Phosphido Bridges

The diphosphido-bridged diiron clusters <i>syn</i>-[{μ_<i>2</i>-P­(CH₂Fc)­H}₂Fe₂(CO)₆] (<b>2a</b>) and <i>anti</i>-/<i>syn</i>-[{μ_<i>2</i>-P­(CH₂Fc)­Me}₂Fe₂(CO)₆] (<b>3</b>), containing covalently linked ferrocenyl (Fc) groups, were synthesized in order to explore the effect of having a redox-active ligand bound to a Fe₂P₂ core as in the covalently linked Fe₄S₄-{μ₂-S­(Cys)}-Fe₂S₂ cofactor of [FeFe]-hydrogenases. The X-ray crystal structure of <b>2a</b> shows an Fe–Fe bond length of 2.630(1) Å and confirms that the two P–H bonds of the bridging 1°-phosphido groups are parallel and are separated by 2.683(2) Å. Cyclic voltammetry and spectroelectrochemistry studies revealed that <b>2a</b>, unusually, undergoes one-electron reduction at −2.18 V (vs Fc⁺/Fc) to give the anion [{μ_<i>2</i>-P­(CH₂Fc)}­{μ_<i>2</i>-P­(CH₂Fc)­H}­Fe₂(CO)₆]^<b>–</b> ([<b>2a</b> – H]^<b>–</b>), which was independently obtained by deprotonation of <b>2a</b> with excess 1,8-diazabicycloundec-7-ene (DBU). The reduction proceeds through the radical anion <b>2a</b>′^{<b>•–</b>} intermediate, which was detected by X-band EPR spectroscopy in situ during electrolysis. The formation of [<b>2a</b> – H]^<b>–</b> from the <b>2a</b>′^{<b>•–</b>} radical formally equates to loss of a hydrogen atom from the bridging P–H group. The result suggests that a new low-energy route for evolution of molecular hydrogen is available in Fe₂E₂ dimers with bridgehead hydrogen atomsi.e. dimers with hydrogen directly bonded to the bridging nonmetal atoms (E = P, S). In contrast to the one-electron reduction behavior of <b>2a</b>, the mixture of dimers <b>3</b> exhibited a two-electron reduction at −2.11 V (vs Fc⁺/Fc) that afforded <b>3</b>^2–. Both dimers catalyze the reduction of protons from <i>p</i>-toluenesulfonic acid, with <b>2a</b> exhibiting higher catalytic currents at lower overpotential

Rhodium Complexes of a Chelating Ligand with Imidazol-2-ylidene and Pyridin-2-ylidene Donors: The Effect of <i>C</i>-Metalation of Nicotinamide Groups on Uptake of Hydride Ion

Rhodium complexes of the imidazolylidene (<i>C</i>-im) <i>N</i>-heterocyclic carbene (NHC) ligand, <i>C</i>-im-pyH⁺, bearing a nicotinamide cation substituent (pyH⁺) have been targeted for ligand-centered uptake and delivery of hydride ion. This work reveals that rhodium­(I) complexes such as [Rh­(<i>C</i>-im-pyH⁺)­(COD)­X]­[PF₆] (<b>1</b>, <b>a</b>: X = Cl, <b>b</b>: X = I) undergo facile <i>C</i>-metalation of the nicotinamide ring to afford rhodium complexes of a novel chelate ligand, <i>C,C′</i>-im-py, with coordinated imidazolylidene (C_im) and pyridylidene (C_py) NHC-donors. Seven examples were characterized and include rhodium­(III) monomers of the general formula [Rh­(<i>C,C′</i>-im-py)­L_<i>x</i>I₂]^<i>z</i>+ (<b>2</b>: <i>z</i> = 1, L = H₂O or solvent, <i>x</i> = 2; <b>3</b>, <b>5</b>, <b>7</b>: <i>z</i> = 0, L = carboxylate, <i>x</i> = 1) and novel rhodium­(II) dimers, the <i>anti/syn</i>-isomers of [Rh₂(<i>C,C′</i>-im-py)₂(μOAc)₂I₂] (<b>4-</b><i><b>anti</b></i>/<i><b>syn</b></i>). The NMR data, backed by DFT calculations, is consistent with attribution of the <i>C,C′</i>-im-py ligand as a bis­(carbene) donor. Single crystal X-ray diffraction studies are reported for <b>2</b>, <b>3</b>, <b>4-</b><i><b>anti</b></i>, <b>4-</b><i><b>syn</b></i> and <b>7</b>. Consistently, within the each complex, the Rh–C_im bond length is shorter than the Rh–C_py bond length, which is the opposite trend to that expected based on simple electronic considerations. It is proposed that intramolecular steric interactions imposed by different rings in the rigid <i>C,C′</i>-im-py chelate ligand dictate the observed Rh–C_NHC bond lengths. Attempts to add hydride to the <i>C</i>-metalated nicotinamide ring in <b>3</b> were unsuccessful. The redox behavior of <b>3</b> and <b>4</b> and, for comparison, an analogous bis­(imidazolylidene)­rhodium­(III) monomer (<b>8</b>), were characterized by cyclic voltammetry, electron paramagnetic resonance (EPR), and UV–vis spectroelectrochemistry. In <b>3</b> and <b>4</b>, the <i>C</i>-metalated nicotinamide ring is found to exhibit a one-electron reduction process at far lower potential (−2.34 V vs. Fc⁺/Fc in acetonitrile) than the two-electron nicotinamide cation-dihydronicotinamide couple found for the corresponding nonmetalated ring (−1.24 V). The <i>C,C′</i>-ligand is electrochemically silent over a large potential range (from −2.3 V to the anodic solvent limit), thus for both <b>3</b> and <b>4</b> the first reduction processes are metal-centered. For <b>4-</b><i><b>anti</b></i>, the cyclic voltammetry and UV–vis spectrochemical results are consistent with a diamagnetic [Rh­(I)­Rh­(II)]₂ tetrameric reduction product. Density functional theory (DFT) calculations were used to further probe the uptake of hydride ion by the nicotinamide ring, both before and after <i>C</i>-metalation. It is found that <i>C</i>-metalation significantly decreases the ability of the nicotinamide ring to take up hydride ion, which is attributed to the “carbene-like” character of a <i>C</i>-metalated pyridylidene ring