Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Incubation: Subthreshold ablation of poly-(methyl methacrylate) and the nature of the decomposition pathways

Abstract: A study of the decomposition of poly-(methyl methacrylate) (PMMA) by pulsed UV laser ablation in the incubation regime is presented here. We propose that incubation proceeds via the photoinduced formation of defects centers; while ablation following incubation, at subthreshold fluences, is a thermally driven phenomena. The light scattering data, in the incubation regime, is consistent with molecular weight reduction via backbone cleavage. The defect centers, C=C at chain ends following backbone cleavage, increase the UV absorption coefficient thereby lowering the ablation threshold. Similarities between the mass spectra of ablative PMMA following incubation and pyrolysis suggest that ablation following incubation is thermally driven. The implications of these results in an extensive and contradictory body of available data are discussed.

Influence of enrichment incubation time on the isolation of Salmonella.

Abstract: The optimum incubation times for Salmonella enrichment cultures were determined by inoculation of enrichment broths onto plating media after 24 hours at 37 C, after 48 hours at 37 C, after a 3-day delayed secondary enrichment (DSE), and after a 5-day DSE procedure. The results showed a step-wise increase in Salmonella isolations with the longer incubation times. Inoculation of the enrichment broths onto plating media after 24 hours incubation followed by a 5-day DSE made possible the detection of 96% to 98% of the Salmonella-positive samples and was the best combination of conditions.

Field study of sex determination in podocnemis expansa from colombian amazonia

Abstract: We studied the relationship between fluctuating temperatures in the field and sex ratios of the giant river turtle (Podocnernis expansa) obtained from nests incubated in seminatural conditions using a stepwise logistic regression model. The number of hours above 31 C and mean temperature above 31 C during day 2930 were the two parameters that best explained sex ratios. We also monitored incubation temperatures of natural nests. Mean incubation temperature and the combination of mean and variance were not predictors of sex ratio. We found a beach effect on sex ratios and incubation time. Natural nests hatched earlier than seminatural nests. Length of the incubation period was negatively correlated with degree days and mean incubation temperature in seminatural nests but not in natural nests. \Ve found no evidence of an influence of length of the incubation period on sex ratio. Our results support current conservation practices in the study region.

Antibody penetration into living cells. IV. Different effects of anti-native DNA and anti-ribonucleoprotein IgG on the cell cycle of activated T gamma cells.

Abstract: Normal T cells bearing receptors for the Fc portion of IgG that were incubated in anti-RNP or anti-DNA at the time of activation with phytohaemagglutinin showed different effects on this activation as determined by flow cytometric analysis of acridine orange stained cells. Incubation in anti-RNP caused an arrest in the progression from the G0 + G1 to the S + G2 phases of the cell cycle. Incubation in anti-native DNA caused activated cells to have an increase in their RNA content without a concomitant increase in their DNA content (DNA block). These effects were not seen in T cells that were depleted of T gamma cells by means of their property of forming rosettes with high affinity for sheep erythrocytes. Use of F(ab')2 fragments of either autoantibody, pre-incubation with aggregated IgG, or incubation with the respective autoantibodies in the cold effectively prevented their effect on the nucleic acid content of T gamma cells. Despite their different effect on the cell cycle both antibodies caused similar increase of 51Cr release of low affinity T cells 6 h after incubation in them. Our findings show that different anti-nuclear antibodies seem to cause different effects upon the cells they penetrate. These differences may have pathogenetic significance in the diseases where these antibodies occur.

Apoptosis induced by progesterone in human ovarian cancer cell line SNU-840

Abstract: Progesterone has been used as an ingredient of anticancer drug for patients with ovarian carcinoma. However, the mechanism of anticancer effects by progesterone has not been understood. In this study, the effects of progesterone on ovarian cancer cells, SNU-840, were investigated. After the incubation with progesterone, the viability of the cells was evaluated by MTT assay. As a result, 45% of the cells were viable after 48 h of incubation with 100 microM progesterone. In addition, [(3)H]thymidine incorporation assay showed that the proliferation of the cells was completely inhibited by progesterone after 48 h of incubation at 100 microM concentration. Colorimetric TUNEL assay revealed the fragmentation of the chromosomal DNA, suggesting that the process of the cell death was apoptosis. The level of the p53 mRNA was determined by northern blotting assay, since many apoptosis processes are mediated by up-regulation of the p53 expression. The level of the p53 mRNA reached its maximum at 12 h and decreased after 24 h of incubation with progesterone. In conclusion, progesterone inhibits the proliferation and elicits apoptosis of SNU-840 cells. Also, it up-regulates the p53 mRNA transiently.