A influência de um programa de treinamento de força muscular, nas fases neurogênica e miogênica, sobre os níveis de IGF-1 em idosas sedentárias

El presente estudio tuvo como objetivo evaluar los efectos del fortalecimiento muscular, en las fases neurogénica y miogénica, sobre el nivel de fuerza muscular y la autonomía funcional de una población de mujeres mayores sanas y sedentarias. La muestra quedó constituida por 40 mujeres, subdivididas de manera aleatoria en: grupo experimental (GE, n = 12; 65,62±5,36 años) y grupo control (GC, n = 11; 71,45±5,72 años). Se utilizó el protocolo de una repetición máxima (1RM) para la evaluación de la fuerza muscular y la batería de test del protocolo del Grupo de Desarrollo Latino Americano para la Madurez (GDLAM) para evaluar la autonomía funcional. Para el análisis estadístico fueron utilizadas las siguientes pruebas: Friedman (GE, en relación a los 3 momentos) seguido de las comparaciones múltiples de Wilcoxon (GC, en relación a los 2 momentos) y Mann-Whitney por el ∆% (comparación inter-grupos). Los resultados en los niveles de fuerza muscular del GE, en la fase miogénica, revelaron ganancias significativas cuando fueron comparados con el pre-test (valores de p: EJ = 0,0001; FJD y FJE = 0,0001; SUP = 0,0001; ET = 0,0001) y en la fase neurogénica (valores de p: EJ = 0,0008; FJD y FJE = 0,0031; SUP = 0,0005; ET = 0,0073). Los tests de autonomía funcional obtuvieron mejoras significativas en el GE: Fase neurogénica (valores de p: IG = 0,0089; C10m = 0,0106; LPS = 0,0005; LPDV = 0,0061; LCLC = 0,0072; VTC = 0,0104) y fase miogénica (valores de p: IG = 0,0001; C10m = 0,0005; LPS = 0,0000; LPDV = 0,004; LCLC = 0,0059; VTC = 0,0003). Así, se pudo concluir que el entrenamiento de la fuerza presentó variaciones estadísticamente significativas en esta variable, sólo en la fase miogénica; además se constataron también disminuciones estadísticamente significativas respecto al tiempo de ejecución de los test de autonomía funcional en la fase neurogénica

Rh-Catalyzed Reactions of 1,4-Benzoquinones with Electrophiles:C-H Iodination, Bromination, and Phenylselenation

Under Rh-catalyzed conditions, typically electrophilic 1,4-benzoquinones exhibit nucleophilic reactivity, such that exposure to appropriate electrophiles generates products of C-H iodination, bromination, and phenylselenation. This provides a mild and general method for direct halofunctionalization, and the first method that can achieve direct C-H phenylselenation of this compound class. The scope and limitations of the new protocols are outlined, and representative derivatizations are highlighted.</p

Determining the Absolute Configuration of Small Molecules by Diffusion NMR Experiments

Enantiomers are ubiquitous in many areas of science, such as pharmaceuticals, agriculture, and food. Nuclear magnetic resonance (NMR) alone is not able to differentiate enantiomers as their spectra are identical. However, these can be distinguished using chiral auxiliaries (such as chiral complexing agents) that form diastereomeric complexes, but absolute identification is still troublesome, usually requiring a chemical reaction with a chiral derivatizing agent. Here, we propose a new method that uses a hybrid mixture of solvating agents in a simple comparison of diffusion NMR experiments, which can discriminate enantiomers in both frequency and diffusion domains, dubbed CHIMERA (CHIral Micelle Enantiomer Resolving Agent). The new method was assessed for twenty-three small chiral molecules using a combination of BINOL and (-)-DMEB, a chiral surfactant, and initial results indicate that absolute configuration can be obtained from a simple experiment

Study of the vertical transport in p-doped superlattices based on group III-V semiconductors

The electrical conductivity σ has been calculated for p-doped GaAs/Al0.3Ga0.7As and cubic GaN/Al0.3Ga0.7N thin superlattices (SLs). The calculations are done within a self-consistent approach to the k→⋅p→ theory by means of a full six-band Luttinger-Kohn Hamiltonian, together with the Poisson equation in a plane wave representation, including exchange correlation effects within the local density approximation. It was also assumed that transport in the SL occurs through extended minibands states for each carrier, and the conductivity is calculated at zero temperature and in low-field ohmic limits by the quasi-chemical Boltzmann kinetic equation. It was shown that the particular minibands structure of the p-doped SLs leads to a plateau-like behavior in the conductivity as a function of the donor concentration and/or the Fermi level energy. In addition, it is shown that the Coulomb and exchange-correlation effects play an important role in these systems, since they determine the bending potential

Drug release mechanisms of chemically cross-linked albumin microparticles: effect of the matrix erosion

Albumin (BSA) microparticles were developed as a biotechnological alternative for drug delivery. Vitamin B12 (Vit-B12) was used as a model drug. The microparticles were obtained from maleic anhydride-functionalized BSA and N′,N′-dimethylacrylamide (DMAAm) in a W/O emulsion without and with PVA. The microparticles produced at 15 min of stirring without PVA showed the best results in terms of size, homogeneity, and sphericity. In such a case, BSA played a role as a surface active agent, replacing PVA. For longer stirring times, BSA was unable to act as an emulsifier. These microparticles showed an uncommon release profile, consisting of a two-step release mechanism, at the pH range studied. Considering that a two-step release mechanism is occurring, the experimental data were adjusted by applying modified power law and Weibull equations in order to describe release mechanism n and release rate constant k, respectively. Each one of the release stages was related to a specific value of n and k. The second stage was driven by a super case II transport mechanism, as a result of diffusion, macromolecular relaxation, and erosion. A third model, described by Hixson–Crowell, confirmed the erosion mechanism. Vit-B12 diffusion kinetics in aqueous solutions (i.e., without the microparticles) follows a one-step process, being k dependent on the pH, confirming that the two-step release mechanism is a characteristic profile of the developed microparticles. The microparticles released only 2.70% of their initial drug load at pH 2, and 58.53% at pH 10