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A Cifuentes

Publications and source records attributed to A Cifuentes.

43 records · Page 3Linked to original sources
PubMed1994

Simulation and optimization of peptide separation by capillary electrophoresis.

The different mobility equations that have appeared in the literature for predicting peptide mobility were compared. A modified equation that relates the mobility of individual proteolytic species of a peptide to its composition has been obtained: mu = 1758 log(1 + 0.297q)/M0.411, where mu is the electrophoretic mobility in 10(-9) m2/s.V, q is the integral value of the charge of the species and M its molecular mass. Also, a rough estimation of the set of pKa values for a peptide was developed. The usefulness of this equation together with a computer program for predicting separations of compounds by capillary zone electrophoresis is demonstrated, employing real electropherograms of peptides from the literature or from experiments.

Amino Acid Sequence↗
PubMed1992

Rapid analysis of whey proteins from different animal species by reversed-phase high-performance liquid chromatography.

This paper explores the possibilities of reversed-phase high performance liquid chromatography (RP-HPLC) for analysing whey proteins from the milk of cows and other animal species. An RP-HPLC method is proposed to separate and quantify bovine whey proteins. Using this method, bovine serum albumin, alpha-lactalbumin, beta-lactoglobulin A and beta-lactoglobulin B were separated in less than 7 min. It is demonstrated that irreversible adsorption of bovine whey proteins occurs on unused columns (i.e. those not previously used to separate proteins). Therefore, prior conditioning of the column with whey proteins is required for valid protein quantification. Conditioning can be achieved by eluting a large amount of at least one of the bovine whey proteins through the unused column. The calibration curve (peak area vs. protein concentration) for the main bovine whey proteins was linear. This method also allowed good separation of caprine and ovine whey proteins and separation of some homologous whey proteins of different animal species. Detection of milk mixtures from different animal species was carried out using this method.

Animals↗
PubMed1980

Comparative evaluation of two methods of natural family planning in Columbia.

Results of a comparative study of the ovulation method (OM) and symptothermal method (STM) of natural family planning in Colombia are presented. Recruitment of volunteer couples began in August, 1976, and continued through December, 1978, during which time 566 couples were randomly assigned to one or the other of the two methods. The study included 3 to 5 months of training in the method assigned, after which the couples entered the follow-up phase of the study. They remained in follow-up until (1) they dropped out or (2) the study closed in June, 1979. Total dropout rates were high for both methods of natural family planning. One year after entry into the follow-up phase of the study, net pregnancy rates were 24.2% for OM users and 19.8% for STM users. Gross pregnancy rates were 29.2% for OM and 26.1% for STM. Differences in pregnancy rates between the two methods were not statistically significant.

Adolescent↗