Jorge Luis Hernández-Piñero

Leaf biomass determination on woody shrub species in semiarid zones

Leaf biomass over 20 native species from thornscrub canopies was evaluated by five non-destructive allometric methods and compared in order to determine the most accurate estimating procedure. Indirect relationships between leaf biomass and some ecological characteristics of the plants may be found by using regression models. Ecological and morphological characteristics of these species were determined using a structural analysis. No single standard method estimated leaf biomass for all species on site due to the diversity of geometric shapes in these species. However, Adelaide, double sampling and the dimensional methods were the most precise, practical and simplest methods for measuring the forage leaf biomass of many shrub species. The linear models gave a better estimate of tree biomass than the logarithmic functions. The regression equations showed a close relationship between foliar biomass and growth parameters.

Delayed lung maturation of foetus of diabetic mother rats develop with a diminish, but without changes in the proportion of type I and II pneumocytes, and decreased expression of protein D-associated surfactant factor.

Newborn children of diabetic mothers have an increased morbidity and mortality because of respiratory distress syndrome. We study lung histogenesis during intrauterine development of offspring of diabetic Sprague‐Dawley rats at 18, 19 and 21 days of gestation (DG). Pregnant rats were grouped into diabetic (streptozotocin‐induced), citrate, and control groups; five female and five male offspring were selected randomly from each group at 18, 19 and 21 DG, and a biopsy of the lung was taken and processed in paraffin for histological examination. The biopsy for the transmission electron microscopy (TEM) analysis was taken at 21 days. A delay in alveolization of the offspring at 18, 19 and 21 days of the diabetic group was observed, which was confirmed at TEM level, and also less quantity of protein D associated to surfactant in diabetic group was detected (P < 0.001). The foetuses of the diabetic group presented a delay in lung histogenesis and in differentiation of the type II pneumocytes cells, but conserved the proportion with a decrease in 50% of pneumocytes, accompanied by a diminish of protein D associated to surfactant factor.

In vivo and In situ Digestibility of Dry Matter and Crude rotein of Honeylocust Pods (Gleditsia triacanthos L.)

Abstract Foroughbakhch, R., Dupraz, C., Hernández-Piñero, J.L., Alvarado-Vázquez, M.A., Guzmán Lucio, M.A. and Rocha Estrada, A. 2006. In vivo and in situ digestibility of dry matter and crude protein of honeylocust pods (Gleditsia triacanthos L.). J. Appl. Anim. Res., 30: 41–46. The aim of this study was to estimate the nutritional content, the rate of digestibility (in situ and in vivo) of nutrients contained in entire pods from four varieties of Gleditsia triacanthos L. Pods of each variety were hand harvested from natural vegetation around Montpellier, France. The in vivo and in sacco techniques were used to estimate degradability of dry matter (DM) and crude protein (CP) using a lot of castrated male Aries Merino sheep and rumen fistulated sheep. The mean daily ingestion value per animal varied between 57–80 g of the dry matter of pods/kg live weight0.75; the digestibility values varied considerably between individuals (44.7–71.9% of the DM). More than 55% of the DM of the pods was digested after an incubation period of 8 h. The protein digestibility showed a rate of particle disappearance (kp=0.06) in rumen inferior to that obtained by the standard diet. The animals with a higher ingestion rate had a lesser digestion. The nitrogen digestibility rate (coefficient of digestive utilization = CDU) was superior for the fistulated animals (CDUN = 50–52%) compared to non-fistulated animals (CDUN=18–30%). The nutrient content and digestion parameters for varieties Milaud and Total were higher than Super-M and Voie-Ferré-Marchandise varieties.

Synthesis and Study of Nanostructures Via Microwave Heating

This work is devoted to microwave heating of graphite, sucrose, calcined sucrose, and a mixture of graphite with sucrose to produce carbon nanotubes (CNTs). The samples were submitted to microwave radiation (power 800W, frequency 2.45 GHz) in air and high vacuum (10 −5 Torr) for 30 – 60 min. The oven temperature was approximately 1200°C. After vaporization the condensed material was collected on various fused silica targets (different morphologies were used). The samples were found to contain a significant proportion of nanotubes, nanoparticles and fibers (1-2.8 micrometers), which appeared to be highly graphitized and helical structured. After deposition, the morphology of carbon nanotubes was studied with SEM, TEM and AFM techniques. It was observed that multi-walled nanotubes (MWNTs) were produced by this method. The morphology of fused silicon based substrates (SiO 2 , SiC) was studied as an important factor for the growth of carbon nanotubes. Many aspects as the size and shape of the obtained nanotubes on different substrates (porous and non-porous fused silicon substrates) were achieved, as well as the concentration of them across the substrate and other properties.