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Biomedical subjects

I Goñi

Publications and source records attributed to I Goñi.

30 records · Page 2Linked to original sources
PubMed1997

pH-sensitive hydrogels based on non-ionic acrylic copolymers.

Hydrogels based on ethoxytriethyleneglycol monomethacrylate/methyl methacrylate copolymers were prepared by free radical polymerization at 70 degrees C in bulk with 2,2'-azobisisobutyronitrile as initiator. The swelling behaviour of the hydrogels was studied by immersion of the films in water and in buffered solutions at various pHs. The hydration process was followed gravimetrically measuring the water uptake of the films with the time of treatment. The kinetics fit adequately a Fickian law for reduced sorption coefficients, Mt/M infinity, lower than 0.6. The values of the diffusion coefficient were lower at neutral pH than at acidic or alkaline pHs, and they seemed to be independent of the copolymer composition. The results obtained were consistent with the stress relaxation model of polymer chains predicted for a relatively fast hydration process. The swelling process is reversible and the polymeric films are stable after repeating cycles of hydration and desorption promoted by the change of pH in appropriate buffered solutions.

Biopolymers↗
PubMed1996

New aspects of the effect of size and size distribution on the setting parameters and mechanical properties of acrylic bone cements.

The effect of the size and the size distribution of poly(methyl methacrylate) (PMMA) beads on the classical kinetic parameters, peak temperature and setting time, for acrylic bone cement formulations prepared with PMMA particles in the range 10-60 microns of average diameter and a relatively wide size distribution is analysed. In addition, the combined effects of the concentration of the free radical initiator benzoyl peroxide and the activator N, N-dimethyl-4-toluidine for the different particle sizes are studied and compared with those commercially available formulations like CMW or Rostal. The results obtained indicated that the use of PMMA particles with average diameter of 50-60 microns, and a relatively wide size distribution (10-140 microns diameter), significantly changes the curing parameters (peak temperature and setting time) of the cement formulations in comparison with the classical behaviour of the commercial systems of CMW and Rostal, without any noticeable loss in the mechanical properties, such as tensile strength, elastic moduli, and compressive strength and plastic strain.

Benzoyl Peroxide↗
PubMed1992

Formation of resistant starch in deproteinized and non-deproteinized beans.

Resistant starch (RS) was determined in deproteinized and non-deproteinized whole and milled beans (Phaseolus vulgaris) after cooking and freezing. The highest RS values were obtained in the whole bean preparations (3.7-8.7%). Milled and milled and deproteinized beans presented lower RS contents (1.64% and 0.91%, respectively). The results suggest that the presence of protein and the particle size are the main factors affecting the formation of RS.

Dietary Fiber↗
PubMed1986

[Anthropometric study of the body composition of a childhood population in Madrid].

Results of some anthropometric variables related to body composition of school children, in Madrid, aged 6 to 14, are reported. Measures were taken by a well-trained staff with accurate instruments and following international proceedings. Data directly obtained were: arm circumference and skinfolds thickness: bicipital, tricipital and subscapular. Results deduced from the former ones, show the composition of an hypothetic mid-arm section and they are: total surface, fat surface, % fat, fat free surface and % fat free substance. These values obtained from a population with an adequate feeding under control, are a data contribution for future studies on collectivities with similar characteristics.

Adolescent↗
PubMed1985

[Use of the calculation of anthropometric values with microprocessors for nutritional diagnosis].

The purpose of this work was to determine the possibility of establishing the most accurate nutritional diagnosis based on anthropometric information in school boys and girls (6 to 14 years), from Madrid (Spain). To carry out this work two well-trained anthropometrists obtained data of total and kneeling height, cephalic and thoracic circumference, and weight from an aleatory sample of 333 boys and girls who study at a national school in Madrid. The collected data presented and analyzed, served as a basis to calculate the fitting equations of each anthropometric variable according to age and sex, as well as some relation among them. Their use simplifies the obtention of the biometric reference values, and allows precise interpolations for concrete ages. All of these algorithms have been translated into BASIC sentences to facilitate its incorporation into any microprocessor. A first diagnostic pattern of the past and present nutritional history of children according to their age and sex, total and kneeling height and weight of each one of them is also presented. The BASIC program, necessary to incorporate it into computers, is included as well.

Adolescent↗
PubMed1985

[Method for calculation in personal computers of expected values of anthropometric variables on body composition].

A program to incorporate in any personal computer (microprocessor) with BASIC language, is herein proposed. This enables calculation of the expected values (50 percentile), and the range of "allowable" variables (3 and 97 percentiles) of the bicipital, tricipital and subscapular cutaneous skinfold thickness, and of the arm's circumference in 6 to 14-year-old boys and girls. It is easily modifiable so as to apply it to other population sectors, and also makes an anthropometric diagnosis. The program facilitates the handling and interpretation of some current biometric variables related to body composition, which are necessary for the full analysis of the actual nutritional status, both of individuals and of population groups.

Adolescent↗