The experiment takes the traditional redox titration of vitamin C using iodine with starch as an indicator, and presents it to the student as a challenge in guided-inquiry format. Two versions, with ...different levels of difficulty, are provided, to accommodate students with varying levels of problem-solving skills. The "challenge" is both quantitative and qualitative: if you were an eighteenth-century sea captain packing for a voyage to the New World, would you take oranges, lemons, limes, or grapefruits to prevent your crew from getting scurvy? The challenge ties in history, nutrition, and health with chemistry, and provides students an opportunity to work with familiar food products in the laboratory.
The demonstrated benefits provided by Atomic Layer Deposition (ALD) in producing films of exceptional uniformity, and conformality, has set the stage for its use in large area, and batch processing ...applications. Two key elements which drive the adoption of ALD for these applications are the ability to scale the film processes from small to large size substrates, and for the effective throughput to be increased in a manner consistent with volume production needs. In this paper we discuss the results of scaling processes from small format substrates to large format substrates, along with a presentation of the parameters which influence throughput. Additionally we describe the basic underpinnings of batch and roll-to-roll ALD systems, and the design factors which must be considered when used in a high volume setting.
Besides its matrix metalloproteinases inhibitory activity, TIMP-1 exhibits other biological activities such as cell survival and proliferation. The intracellular signalling pathway elicited by TIMP-1 ...begins to be elucidated. We have shown previously that the caspase-3 and the p38a MAP kinase were activated during TIMP-1-induced UT-7 cells erythroid differentiation. In this study, we demonstrated that TIMP-1 differentiating effect can be extended to the IL-3-dependent myeloid murine 32D cell line and human erythroid progenitors derived from cord blood CD34 super(+) cells. By performing small interfering RNA transfection and using chemical inhibitors, we evidenced that caspase-3 was involved in TIMP-1 differentiating effect. We then identified the MEKK1 kinase as a caspase-3 substrate and demonstrated that the MEKK1/MEK6/p38a pathway was activated downstream the caspase-3 in TIMP-1-induced hematopoietic differentiation.Leukemia (2007) 21, 595-603. doi:10.1038/sj.leu.2404540; published online 15 February 2007
Besides its matrix metalloproteinases inhibitory activity, TIMP-1 exhibits other biological activities such as cell survival and proliferation. The intracellular signalling pathway elicited by TIMP-1 ...begins to be elucidated. We have shown previously that the caspase-3 and the p38alpha MAP kinase were activated during TIMP-1-induced UT-7 cells erythroid differentiation. In this study, we demonstrated that TIMP-1 differentiating effect can be extended to the IL-3-dependent myeloid murine 32D cell line and human erythroid progenitors derived from cord blood CD34(+) cells. By performing small interfering RNA transfection and using chemical inhibitors, we evidenced that caspase-3 was involved in TIMP-1 differentiating effect. We then identified the MEKK1 kinase as a caspase-3 substrate and demonstrated that the MEKK1/MEK6/p38alpha pathway was activated downstream the caspase-3 in TIMP-1-induced hematopoietic differentiation.
Fish‐habitat models for streams were developed to help explain the decline and possible replacement of smallmouth bass Micropterus dolomieu by largemouth bass M. salmoides in the Ozark Border region ...of Missouri. We identified habitat conditions associated with the distribution and abundance of both species in sympatric and allopatric situations by means of correlation analysis and multiple linear regression models. Maximum summer temperature and percent pool area explained most of the variability in total densities, adjusted densities (fish larger than 100 mm total length), and biomass for both species. Smallmouth bass were negatively associated with each variable, whereas largemouth bass were positively associated. Physical habitat that is usable as cover was not associated with the abundance of either species. Final models explained about 50% of the variation in the population characteristics of both species and showed good accuracy and precision across years. Adjusted‐density models appeared to be the most appropriate management tool and had the greatest predictive abilities across years. Results suggest that human activities have altered stream environments to favor largemouth bass populations in the Ozark Border region.
PDF
