Chitosan/Poly(Dllactide-Co-Glycolide) Scaffolds for Tis- sue Engineering

Abstract Chitosan/poly(DL-lactide-co-glycolide) (Ch/DL PLG) composite scaffolds were fabricated by freeze-drying lyophilization, and were evaluated and compared for use as a bone regeneration scaffold through measurements of the compression mechanical properties of the porous scaffolds. Also, In vitro cell culture of Sprague-Dawley rat's osteoblasts were used to evaluate the phenotype expression of cells in the scaffolds, characterizing the cellular adhesion, proliferation and alkaline phosphatase activity. The gene expression of osteocalcin, sialoprotein, alkaline phosphatase, Type I collagen and TGFb1 were confirmed in the samples; moreover, it was confirmed, the mineralization by IR spectra and EDS analysis. Our results thus show that Ch/DL PLG scaffolds are suitable for biological applications

Efecto de tratamiento térmico en aleaciones feal1% at li expuestas a pruebas de oxidación en diferentes temperaturas.

The addition of lithium in intermetallic alloys based on Fe3Al improves mechanical properties and corrosion resistance. This alloys are produced by conventional induction furnance techniques, using SiC crucibles and a thermal treatment of 400º C by 144 h. Oxidation tests of high temperature were carried out in a Thermogravimetric analyzer (TGA) in a static atmosphere at 650, 800, and 900 ºC. this tests revealed a differences in the oxidation kinetic between the samples with the thermal treatment and those without the treatment. A scanning electron microscopy (SEM) analysis, revealed that the oxidation layer is more uniform when the thermal treatment is applied.La adición de Li en aleaciones intermetalicas base Fe3Al ayuda en la mejora de propiedades mecánicas y resistencia a la corrosión. Las aleaciones se producen con técnicas convencionales de vaciado usando crisoles de SiC y se someten a un tratamiento térmico de 400ºC por 144h. Se realizaron pruebas de oxidación de alta temperatura en termobalanza con atmósfera estática a temperaturas de 650, 800 y 900 ºC las cuales indicaron una diferencia en la cinética de oxidación entre las muestras con tratamiento térmico y sin el. Por análisis de Microscopía electrónica de barrido se pudo ver que la capa de oxidación es más uniforme cuando se tiene tratamiento térmico

Opuntia ficus-indica Extract as Green Corrosion Inhibitor for Carbon Steel in 1 M HCl Solution

The effect of Opuntia ficus-indica (Nopal) as green corrosion inhibitor for carbon steel in 1 M HCl solution has been investigated by using weight loss tests, potentiodynamic polarization curves, and electrochemical impedance spectroscopy measurements. Also, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) analysis were performed. The inhibitor concentrations used ranged from 0 to 300 ppm at 25, 40, and 60°C. Results indicated the inhibition efficiency increases with increasing extract concentration and decreases with the temperature, and the inhibitor acted as a cathodic-type inhibitor which is physically absorbed onto the steel surface. In fact, the adsorption of the inhibitor on the steel surface follows the Langmuir adsorption isotherm, indicating monolayer adsorption. The presence of heteroatoms such as C, N, and O and OH groups were responsible for the corrosion inhibition

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data