Relative Handgrip Strength as a Simple Tool to Evaluate Impaired Heart Rate Recovery and a Low Chronotropic Index in Obese Older Women.

The aim of the present study was to compare differences in heart rate response following a treadmill exercise test in elderly obese women categorized into groups based on relative handgrip strength. Eighty-eight obese elderly women who were between the ages of 60 and 87 participated in the study and were categorized and enrolled to one of two groups based on lower (< 1.51 m2) or higher (≥ 1.51 m2) relative handgrip strength, respectively. The heart rate recovery in the first and second minutes following the treadmill exercise test and the chronotropic index were compared between groups. The higher relative handgrip strength group presented a significantly higher peak heart rate during exercise and a quicker heart rate recovery following exercise versus the lower relative handgrip strength group (p<0.05). Furthermore, there was a tendency (p=0.059) toward a significantly greater chronotropic index in the higher versus the lower relative handgrip strength group. In conclusion, elderly women with greater relative handgrip strength also demonstrated a better heart rate response during and following exercise, possibly indicating better autonomic balance. The relative handgrip strength might be an important and inexpensive tool for the elderly obese women to indirect assess cardiovascular health.

Estimation of solubility effect on the herbicide controlled-release kinetics from lignin-based formulations.

Understanding the main phenomena involved in the controlled-release kinetics of herbicides in a water bath is a very important requisite for diffusive- parameter estimation, because, some mathematical models based on Fick's second law for diffusion have been developed to describe the controlled-release kinetic data. However, the validity of these models is restricted to the following assumptions: (1) the formulation is an isothermal slab; (2) the release occurs through the two faces of the slab; (3) the herbicide is dissolved in the water contained in the slab pores at a concentration less than the saturation concentration (cis); (4) the total sum of the individual volumes of the pores is epsilonAL (epsilon is the slab porosity, A is the slab area, and L is the slab thickness); and (5) the initial concentration of herbicide in the pores is M0/epsilonAL (M0 is the initial amount of herbicide in the matrix). The fourth assumption may be invalid for mathematical description of systems in which the herbicide concentration in the slab may be above the saturation concentration. If this were true, the final assumption would also be invalid, because the initial concentration of herbicide in the pores is cis in this case. This work presents a study of the solubility effect on the controlled-release kinetics of herbicides from lignin matrices.

Alternative approach for utilization of pentose stream from sugarcane bagasse by an induced flocculent Pichia stipitis.

A new approach for the utilization of hemicellulosic hydrolysate from sugarcane bagasse is described. This approach consists of using the hydrolysate to dilute the conventional feedstock (sugarcane juice) to the usual sugar concentration (150 g/L) employed for the industrial production of ethanol. The resulting sugar mixture was used as the substrate to evaluate the performance of a continuous reactor incorporating a cell recycle module, operated at several dilution rates. An induced flocculent pentose-fermenting yeast strain was used for this bioconversion. Under the conditions used, the reactor performance was satisfactory at substrate feed rates of 30 g/(L h) or less, corresponding to an ethanol productivity of about 11.0 g/(L h) and an overall sugar conversion >95%. These results show real advantages over the existing alternatives for a better exploitation of surplus bagasse to increase industrial alcohol production.

Modeling of 2,4-dichlorophenoxyacetic acid controlled-release kinetics from lignin-based formulations.

The second Fick's law of diffusion, considering boundary conditions that at both slab faces the concentration of herbicide is equal to zero (sink conditions), has been adequate to describe our kinetic data obtained from experiments on 2,4 -dichlorophenoxyacetic acid, (2,4 - D) released from lignin-based formulations in a water static bath system. However, the same model proved to be invalid in describing the experimental data obtained with ametryn (2-ethylamino-4-isopropylamino-6-methylthio-1,3,5-triazine) and diuron (3-[3,4-dichlorophenyl]-1,1-dimethylurea) formulations in a water dynamic bath system. For ametryn and diuron formulations, because of the lower aqueous solubility of these herbicides, it was necessary to model a stagnant film at the formulation surface to describe better the release kinetics because the model incorporating sink conditions is insufficient. This study presents a new mathematical modeling of experimental data obtained with 2,4-D formulations in a water static bath system. The new model incorporates a stagnant film as the boundary condition at the formulation surface, and its diffusion coefficient value is more precise than the one estimated by the model employing sink conditions.