This study was designed to determine the effect of collaborative learning on student attitudes and performance in an introductory chemistry laboratory. Two sections per semester for three semesters were randomly designated as either a control section or an experimental section. Students in the control section performed most labs individually, while those in the experimental section performed all labs in groups of four. Both quantitative and qualitative measures were used to evaluate the impact of collaborative learning on student achievement and attitudes. Grades did not differ between the two sections, indicating that collaborative learning did not affect short-term student achievement. Students seemed to develop a more positive attitude about the laboratory and about chemistry in the collaborative learning sections as judged from their classroom evaluations of the teacher, the course, and the collaborative learning experience. The use of collaborative learning in the laboratory as described in this paper therefore may provide a means of improving student attitudes toward chemistry.

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General Chemistry I historically had one of the highest failure and withdrawal rates at Penn State Berks, a four-year college within the Penn State system. The course was completely redesigned to incorporate more group work, the use of classroom response systems, peer mentors, and a stronger online presence via the learning management system (ANGEL). Five years of data about the redesigned course were compared with the previous five years. The redesigned course significantly improved student success as measured by the average GPA and lower withdrawal rates. Student achievement in the subsequent course, General Chemistry II, has also improved, suggesting that not only are more students completing the first course, but they are also completing the course with better preparation for the next course. Student ratings have improved for the course, showing increased satisfaction with both the course and the instructor. The findings from 10 years of data suggest significant improvements in student success are possible for General Chemistry I.

The patterns of Glut1 and Glut3 glucose transporter protein and mRNA expression were assessed during embryogenesis of chicken brain and skeletal muscle, Glut4 protein levels were also evaluated in skeletal muscle and heart, and Glut1 was examined in the developing heart and liver. Glut1 protein expression was detectable throughout brain ontogeny but was highest during early development. Glut1 mRNA levels in the brain remained very high throughout development. Glut3 protein was highest very early and very late and mRNA was highest during the last half of development. In embryonic skeletal muscle, the levels of Glut1 and Glut3 proteins and mRNA were highest very early, and declined severely by mid-development. Glut1 protein and mRNA in the heart also peaked early and then decreased steadily. Although Glut1 mRNA levels were consistently high in the embryonic liver, Glut1 protein expression was not detected. These results suggest that (1) Glut1 is developmentally regulated in chick brain, skeletal muscle, and heart, (2) Glut1 mRNA is present in liver but does not appear to be translated, (3) Glut3 in brain increases developmentally but is virtually absent in muscle, and (4) Glut4 protein and mRNA appear to be absent from chick heart and skeletal muscle.

This study investigated the teratogenicity of ethanol in several different strains of chickens. The chick embryo provides a useful model for studying the fetal alcohol syndrome. Two broad classifications of chicks, each containing many strains, are commercially available for use: broilers and layers. Teratogenicity of ethanol in broilers and layers was studied by examining three different parameters: embryo weight, ratio of torso weight to head weight, and embryo viability. Broilers and layers experienced similar ethanol-induced reductions in embryo weight, Broiler embryos experienced a preferential ethanol-induced suppression of head growth. Differences in viability between different strains were found, but no clear pattern between broilers or layers could be determined, possibly due to environmental conditions. The data presented here suggest that the strain of chick and the handling of the eggs are important considerations when studying the teratogenicity of ethanol. An ethanol dose-response test should be periodically performed as a check on environmental conditions affecting the eggs--conditions that are beyond the control of the researcher.

A substantial writing assignment in an organic chemistry course provides a means of allowing students to direct their own learning about a specific application of organic chemistry. The use of peer review provided additional benefits: students learned organic chemistry from reading each others' papers and learned more about how classmates write about chemistry. Recommendations about how best to collaborate with a librarian in the design of a writing assignment that involves substantial library research are presented. One of the main features of effective assignments is the statement of clear expectations about assessment of the writing. The explicit criteria used to grade the papers are described. A substantial writing assignment such as this one can provide a means of moving an organic course from instructor-centered to student-centered.

An extraordinarily diverse literature describes the cellular/tissue systems in which the molecular effects of both acute and chronic alcohol exposure seem to be mediated by changes in polyamine levels and/or ornithine decarboxylase (ODC) activity. The single unifying factor that links most of these studies is that they all, in some way, involve tissues that are undergoing relatively rapid cell division. Non-dividing cells expressing the NMDA receptor are a notable exception in that ethanol and the polyamines seem to act via discrete regions of that receptor. Under most cellular conditions, ODC activity is a reflection of the relative tissue polyamine content, and an increase in ODC activity and polyamine content seems to be one of the early events in the progression of quiescent cells toward cell division. Thus, it is not surprising that ethanol, which has been widely reported to delay cell division, should be found to interact with the ODC/polyamine pathway. Perhaps the most unique aspect of these studies is the fact that, with rare exception, both acute and chronic ethanol exposure have been found to slow growth and to lower tissue polyamine (putrescine) content. Furthermore, in most studies, the ethanol-induced suppression of cell division could be overcome by the administration of exogenous putrescine. These data suggest that the ethanol-induced suppression of cell division resulted from the loss of putrescine. In addition, because the cells were able to respond to the exogenous putrescine, the studies suggest that the signaling pathway remained intact beyond the polyamine synthesis step.(ABSTRACT TRUNCATED AT 250 WORDS)

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