Detection in liquid chromatography.
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Carbohydrates↗
Biomedical subjects
J Mazzeo
Publications and source records attributed to J Mazzeo.
Determination of peptide 520 in human plasma using post-column photolysis with electrochemical detection in liquid chromatography.
A simple LC method for the determination of peptide 520 in human plasma was developed. Based on micellar chromatography, sodium octyl sulphate (SOS) was added into the mobile phase in order to separate the peptide from human plasma components. The procedure was fast and sensitive for the determination of the peptide in untreated human plasma. The electrochemical (EC) detection limit for peptide 520 in human plasma was 0.5 microgram ml-1. Linearity of the calibration plot for peptide 520 in human plasma was 0.999. This approach represents a direct injection technique for the potential detection and analysis of numerous peptides in biofluids, besides just plasma, with absolute quantification.
Chromatography, Liquid↗
Children's solution strategies and mental rotation: evidence for a developmental shift.
We examined children's ability to anticipate the appearance of transformed multicomponents using visual stimuli with variations of a mental rotation task. We hypothesized that (a) performance would depend on the presence, location, and spatial relationship of specific stimulus features, and that (b) younger children would use a single component to make their predictions, whereas older children would be more likely to use multiple components. In Study 1, 40 first-, and fifth-grade subjects were presented with 32 rotation problems consisting of varied stimulus characteristics; subjects selected the correct option from a field where foils were indicative of the strategy used. Analyses of variance and log linear analyses revealed the hypothesized stimulus effect differentially associated with the children's ages. In Study 2, sixty 5-, 7-, and 9-year olds confronted 64 mental rotation problems with multicomponent stimuli and a construction task. Results and implications confirmed those of Study 1.
Attention↗
Radiologic total lung capacity measurement. Development and evaluation of a computer-based system.
The development of a computer-based radiologic total lung capacity (TLC) measurement system designed to be used by non-physician personnel is detailed. Four operators tested the reliability and validity of the system by measuring inspiratory PA and lateral pediatric chest radiographs with a Graf spark pen interfaced to a DEC VAX 11/780 computer. First results suggest that the ultimate goal of developing an accurate and easy to use TLC measurement system for non-physician personnel is attainable.
Adult↗
Visual perspective taking in children: further ramifications of an information-processing model.
Forty children between ages 6 and 8 were administered a set of spatial perspective tasks. On half of the items, children responded by rotating a duplicate of the target display; on the remainder, children reconstructed the displays to correspond to a perspective view. The displays differed as to whether they contained marked or unmarked objects. On the basis of an information-processing analysis of these tasks, we predicted that the response-type variables and stimulus variables would interact in known ways. Analysis of variance results revealed a good fit with the hypothesized outcomes. Main effects were detected for age, which favored older children, and for display, which favored unmarked objects; the rotation task proved easier. Significant interactions revealed that task demands increasing task difficulty were more problematic in the construction task than in the rotation task, as predicted.
Child↗
A general framework for evaluating the reliability of medical measurement systems.
Measurements of physical and social phenomena are often used in the decision-making process despite the error introduced by human and context variation. It would be advantageous to a decision maker to know the sources and magnitudes of such errors in using a measurement system or in choosing among alternative measurement systems. This paper describes an approach to determining the reliability of a measurement procedure called generalizability (G) theory. G theory uses the results of a random-effects analysis of variance to estimate the magnitude of error variability associated with each of several potential sources. These estimates can then be used to calculate a number of indices which typify the amount of precision provided by a measurement system in a particular context of usage. The major concepts of G theory are described and illustrated in the context of evaluating a radiologic total lung capacity measurement system.
Analysis of Variance↗
Comprehension of Euclidean space in young children: the early emergence of understanding and its limits.
In two studies Ss (N = 114) aged 3-5 years of age were assessed as to their ability to reconstruct or recognize spatial displays depicting Euclidean geometric features. The Ss responded either with the standard display present or in its absence, a memory condition. Items differed as to whether the objects located in the plane required attention to either one axis, the horizontal or vertical, or to both. In Study I Ss constructed their matches with an open-ended assessment device, while in Study II, they selected the match from a field of four distractors. Results from both studies were convergent despite differences in assessment technique and specifics of data analysis, and indicated an effect for age and condition, and that children do less well when dealing with double-axis displays in the memory condition. In addition, it appears that males were less attentive to display orientation cues than were females. Results are discussed in terms of Piagetian theoretical formulations about children's spatial development, their sensitivity to Euclidean spatial features, and the lack of synchrony between perceptual abilities and memory.
Attention↗
Attitudes of pediatricians toward maternal employment.
The largest number of women in history is employed outside the home including 55% of mothers with children less than 18 years of age. The attitudes of pediatricians toward employed mothers were assessed by a mail survey to the entire membership of the American Academy of Pediatrics. Usable responses were received from 5,758 pediatricians (31%). Adequacy of child care and economic necessity were ranked as the most important factors considered by responding pediatricians when advising a mother inquiring whether she should work outside the home. One third of the respondents stated the child can be any age when the mother becomes employed. The majority of respondents did not feel there was a difference between children of employed mothers and homemaker mothers. Special considerations for employed mothers were provided by half of the respondents, more frequently by female than male pediatricians. Most respondents are supportive of mothers working outside the home, but bias against employed mothers does exist. Pediatricians whose spouses do not work outside the home, those in older age groups, and male pediatricians tended to hold more traditional attitudes toward maternal employment.
Age Factors↗