Biomedical subjects

D D Chavis

Publications and source records attributed to D D Chavis.

3 recordsLinked to original sources

PubMed1993

Computer-generated slide graphics: an exciting advancement or a problem?

Computer-generated slide graphics have significantly altered the face of audiovisual presentations. However, it remains to be determined if dramatic effects enhance presentation clarity and increase information retrieval. This study compared color combination and print type graphics. Ninety medical students were shown a 29-minute, 45-slide presentation addressing aspects of plastic surgery. Each slide represented one of 15 color combinations and one of 3 fonts. The students studied each slide for 10 seconds and then in 25 seconds recorded all information they could recall. Statistical analysis (using ANOVA) revealed a significant difference in information retrieval among slides and a significant interaction between color and font. The "best" was orange block print on a raspberry background. The "worst" was yellow cursive print on a black background. This study demonstrated that (1) color influences information gleaned from a slide presentation and (2) font type simplicity may result in improved retention.

Audiovisual Aids↗

PubMed1988

Viability maintenance of mammary epithelial cells in vitro.

Mammary epithelial cells were isolated from mice lactating for 6 to 10 days and incubated in plastic culture dishes for 10 days. Viability of the cells was tested daily for 8 different treatment regimens including control (Minimum Essential Medium and antibiotics). Tested in cultures were horse serum, a collagen gel matrix, the lactogenic hormones prolactin, insulin, cortisol and all combinations of the above. Effectiveness of treatment was compared each day using the Duncan's New Multiple Range Test (DNMRT) and over the entire 10 day experimental period using regression analysis. After 1 day the collagen gel matrix was the most effective treatment followed by lactogenic hormones and horse serum. On days 2, 4 and 5, horse serum alone was the best treatment while day 3 demonstrated a slight superiority for hormones only. By day 6, and until day 10, a combination of horse serum and hormones maintained viability most successfully. The second and third most effective treatments during this portion of the experimental period were a combination of all three components and hormones alone, respectively. These data support the concept of complex support for mammary epithelial cell viability by a collagen gel matrix accompanied by three known hormones and unknown factors in horse serum.

Animals↗

PubMed1986

Changes in macroingredients of guinea pig milk through lactation.

Milk samples were collected daily from English short-hair albino guinea pigs for 21 d. Analyses included protein, fat, lactose, ash, calories, and specific gravity. All components except lactose increased in concentration gradually from the beginning to end of lactation. Protein percentage began at 6% on d 1 and was 14% on d 21. The pattern of increase was either quadratic or exponential but not rectilinear. Patterns were similar for fat, ash, and calories. Fat on d 1 was 5.6% and 9.0% on d 20. Ash was .97% on d 1 and 1.4% on d 19. Calories per gram milk were 939 on d 1, increasing gradually to 1874 on d 21. Lactose dropped from 5.5% on d 1 to 5.0% on d 2. It remained at 5% until d 6, when it began a gradual decline to .5% on d 20. Thickening of milk and increasing concentrations of protein, fat, ash, and calories, as well as a marked drop in milk volume, resulted from the precipitous decline in lactose concentration of .27%/d from d 6 to 21. Because lactose is the primary controller of osmotic equilibrium and, therefore, the primary regulator of the water content of milk, its decrease in concentration explains the decline in milk volume and the concomitant increases in fat, protein, and solids from d 6 to the end of lactation.

Animals↗