Abstracts
Nº 23
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Abstracts |
Nº 23
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Technical and Natural Sciencies
Development of biomaterials for odontoestomatologic implants |
Oscar Deccó, Omar Giorgi, Diego Amaya et al. |
| Key Words: biomaterials - odontological implants - osseous integration |
| IThis project was aimed to find biomaterials suitable for implants in animals for experimentation, and to assess osseous integration in the interaction between the specimens used and the biological environment, considering that one of the important factors for osseous integration is given by the physical and chemical features that the implants' surface can present. In titanium implants, the surface treatment conducted on them is an influential factor over osseous integration; it is essential to create an oxide layer in their surface for them to behave as ceramics, with a dielectric coefficient similar to bone, thus allowing the specimen an osseous integration to the host. The research was addressed to the study of osseous growth, regarding quality and quantity, in animals for experimentation (rabbits and pigs), using grade II titanium implants, the surface of which was treated with electrochemical methods, achieving layers with a thickness between 50 - 500 Å. The studies carried out macroscopically and microscopically have shown that the implants treated electrochemically have an osseous growth regarding quality and quantity above titanium implants with surface treatment through their mechanization. This kind of treatment could allow the manufacturing of dental implants with the properties of those covered by hydroxyapatite, and in turn to maintain the properties of pure titanium implants. |
Human synovial joints lubrication. Computacional biomechanics |
José Di Paolo, Diego M. Campana, Sebastián Ubal, Carlos M. Corvalán |
| Key Words: synovial joints - lubrication - poroelastic material - finite element |
| Computacional results of a simple mechanical model having common characteristics with synovial joints are presented. The model describes the lubrication phenomenon taking place between two cylindrical surfaces covered by elasto-porous materials. Deformations, pressures and exudations on the lubricated surfaces are locally calculated as well as the amount of lubricating liquid between them. For that purpose the employed F.E.M. is coupled with suitable techniques to parameterize the unknown location of the outflow boundary with zero pressure gradient. Several conclusions are presented regarding the self-lubricating and low friction characteristics of synovial joints and their connections with the liquid exuded by the porous surfaces. |
Relationship between the structure of a natural arboreal system, and the hydric, and nutritional balance of the soil. |
José Casermiero, Antonio De Petre, estela Spahn, Ricardo Valenti |
| Key Words: forest environments - natural pastures - forest soils. |
| The general objective of this work was to evaluate the existing relationships between the herbaceous-arboreal system, and the hydrologic and nutritional characteristics of the soils that support them in an area of the native woodland located in the North Center of the Province of Entre Ríos (Argentina), 23 km from Bovril (31º 22' SL, 59º 30' WL) Department of La Paz. Phytogeographically, it corresponds to the Province of the Espinal, Ñandubay district, with humid, mild climate, and average rainfall around 1100 mm per year, annual average temperature 18ºC, with hydric deficit in summer and winter, with clayish, compact, and likely-to-become-flooded soil. The ignorance of the relationships from the holistic point of view between native men, livestock, pastures, and forest determined the loss of balance, of the system's structure, productivity, and stability. The main use is related to livestock and forests, and to a lesser extent, agriculture. The species of the Prosopis genus (locust tree, and "ñandubay") , and Acacia ("brea", and "espinillo") are important compounds of this ecosystem, providing indirect and direct forage, they regulate the hydric and nutritional balance, and they also improve pastures, and meadows. The methodology used allowed to characterize the vegetation, climate, the hydric relationship, and the edaphic variables. |
Study of isolated bioactive compounds of plants native from Entre Ríos used in popular medicine. |
Eduardo Vivot , Juan de D. Muñoz, María del Carmen Cruañes; María J. Cruañes. |
| Key Words: Medicinal plants - bioactive compounds - popular medicine. |
| The vegetable species Polygonum punctatum Elliot var. aquatile (Martius) Fasset, Lithrea molleoides (Vell.) Engl., Myrcianthes cisplatensis (Camb.) Berg, Sebastiania brasiliensis Spreng., and Sebastiania klotzschiana (Muell. Arg.) Muell. Arg., autochthonous from the province of Entre Ríos (Argentine), which are used in popular medicine, were studied trying to validate the potential therapeutic antimicrobial, and antiviral effects. The dichloromethanic, methanolic, hydroalcoholic extracts, and infusion in water were tested through the Diffusion Test in solid medium, using eight strains of bacteria, and standardized fungi. The tested extracts displayed antimicrobial activity in all the cases, at least, before one of the tested strains. The bioguided fractionation of the ethanol extract at a 50% of S. brasiliensis provided an active fraction against Staphylococcus aureus, Micrococcus luteus, and Mucor sp., which under the spectroscopic analyses (IR, UV, MS), allowed to detect a phenolic compound of PM=410, whose structural elucidation is being studied. The antiviral activity tested with the watery infusion extracts was observed in the Polygonum punctatum, Lithrea molleoides, Sebastiana brasiliensis, and Sebastiana klotzschiana species, proving inhibition at a 99%, at least against one of the viruses, Herpes Simplex Virus (HSV-1)G, Syncitial Respiratory Virus (SRV), and Serotype 7 Adenovirus (ADV-7). |
Foliar anatomy of some species of the Schinus L. (Anacardiaceae) genus. |
Magda Schneeberger, María E. Moya, María E. Carriello |
| Key Words: Schinus - epidermis - stomas - main sheaf - mesophyll. |
| The systematic works carried out in relation to the Anacardiaceae family have had difficulties as regards the location of some species, as happened with Schinopsis heterophylla Ragonese et J.A. Castigl. Carrying out different types of studies, among them, the one of foliar anatomy, allowed to conclude that this must be considered as one species, and not as a synonym of Schinopsis lorentzii (Griseb) Engler. The Schinus L. genus, which belongs to the Anacardiaceae family, presents among some of its species certain systematic doubts. With the aim of contributing to solve them, it was proposed as objective to study the foliar anatomy of 8 species, and 10 varieties of this genus, using fresh material coming from herbarium. The transections were carried out in free hand at the half third level of the widest part of the leaf, or the foliole, decolorized with sodium hypochlorite at a 50%, colored with safranin, and mounted with glycerin gelatin. The observation was carried out with an optic, and scanning electron microscope (SEM), drawn in free hand, and with camera lucida. The epidermis (adaxial, and abaxial), sub-epidermis (hypodermis, and collenchyma), mesophyll, main sheaf, and crystals were characterized. Differences at epidermic level were found: between forms, and types of stomas, between contours of anticlinal walls, and in the thickness of the cuticle among species, and varieties. Differences were found at the level of transections, between the main sheaf, and the mesophyll. According to this, differences between the varieties of each species, and between the species themselves were established. |