Claudia Hernández-Aguilar

Study of Thermal and Structural Properties of Starch Granules from Different Maize Genotypes

The thermal and structural properties of starch granules of four maize genotypes (Palomero Toluqueño native maize, HS-2 commercial hybrid, L3-Q2 M09 experimental hybrid and Cacahuacintle native maize) were studied. By using adiabatic scanning calorimetry (ASC), the specific heat capacity (cp(T)) of these samples was obtained. Also, by integration of the area under the cp(T) curves, the enthalpy for the starch gelatinization was determined, from which the percentage of gelatinized starch granules was obtained as a function of the temperature. From the X-ray diffraction patterns of the starch granules, the degree of crystallinity of the samples was derived. The average size of the starch granules, for the different maize genotypes, was calculated from the images obtained by Scanning Electron Microscopy (SEM). We found a correlation between the enthalpy of gelatinization and the average size of starch granules, and also between the degree of crystallinity and the average size of the starch granules.

Quantum mechanical model for the anticarcinogenic effect of extremely-low-frequency electromagnetic fields on early chemical hepatocarcinogenesis

Using the conventional Haberkorn approach, it is evaluated the recombination of the radical pair (RP) singlet spin state to study theoretically the cytoprotective effect of an extremely-low-frequency electromagnetic field (ELF-EMF) on early stages of hepatic cancer chemically induced in rats. The proposal is that ELF-EMF modulates the interconversion rate of singlet and triplet spin states of the RP populations modifying the products from the metabolization of carcinogens. Previously, we found that the daily treatment with ELF-EMF 120 Hz inhibited the number and area of preneoplastic lesions in chemical carcinogenesis. The singlet spin population is evaluated diagonalizing the spin density matrix through the Lanczos method in a radical pair mechanism (RPM). Using four values of the interchange energy, we have studied the variations over the singlet population. The low magnetic field effect as a test of the influence over the enzymatic chemical reaction is evaluated calculating the quantum yield. Through a bootstrap technique the range is found for the singlet decay rate for the process. Applying the quantum measurements concept, we addressed the impact toward hepatic cells. The result contributes to improving our understanding of the chemical carcinogenesis process affected by charged particles that damage the DNA.

Sustainability assessment of traditional maize (Zea mays L.) agroecosystem in Sierra Norte of Puebla, Mexico

ABSTRACT The sustainability of the traditional maize agroecosystem in Ahuazotepec, Mexico, was evaluated using a cluster analysis for the typification of the producers and the Framework for Assessing the Sustainability of Natural Resource Management Systems approach for the sustainability assessment. Results revealed three groups within the agroecosystem: low-traditional, medium-traditional, and transition. Clusters differed in grain yield, income, age, education, organization, production practices, and complementary economic activities. Sustainability evaluation showed that productivity was the most influential attribute as the grain yield determined how efficiently the production resources are utilized, which in turn influences some environmental and social attributes. Information obtained allows the generation of a baseline and specific suggestions for improving sustainability of the clusters.