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A database of 91 chemicals with published data from both transgenic rodent mutation (TGR) and rodent comet assays has been compiled. The objective was to compare the sensitivity of the two assays for detecting genotoxicity. Critical aspects of study design and results were tabulated for each dataset. There were fewer datasets from rats than mice, particularly for the TGR assay, and therefore, results from both species were combined for further analysis. TGR and comet responses were compared in liver and bone marrow (the most commonly studied tissues), and in stomach and colon evaluated either separately or in combination with other GI tract segments. Overall positive, negative, or equivocal test results were assessed for each chemical across the tissues examined in the TGR and comet assays using two approaches: 1) overall calls based on weight of evidence (WoE) and expert judgement, and 2) curation of the data based on a priori acceptability criteria prior to deriving final tissue specific calls. Since the database contains a high prevalence of positive results, overall agreement between the assays was determined using statistics adjusted for prevalence (using AC1 and PABAK). These coefficients showed fair or moderate to good agreement for liver and the GI tract (predominantly stomach and colon data) using WoE, reduced agreement for stomach and colon evaluated separately using data curation, and poor or no agreement for bone marrow using both the WoE and data curation approaches. Confidence in these results is higher for liver than for the other tissues, for which there were less data. Our analysis finds that comet and TGR generally identify the same compounds (mainly potent mutagens) as genotoxic in liver, stomach and colon, but not in bone marrow. However, the current database content precluded drawing assay concordance conclusions for weak mutagens and non-DNA reactive chemicals.

Char structural changes occurring during gasification are normally only related to conversion and few data is published on the effect of carbon dioxide partial pressure on the extent of pore development. In this study, the char–CO2 reactivity and consequential pore development of different Highveld coal chars were investigated over a wide pressure range. Reactivity experiments were performed in a fixed bed reactor under reaction controlled conditions. The initial reaction rate was found to be solely a function of temperature and CO2 partial pressure and was well described by the Langmuir Hinshelwood rate equation. Surface analyses were performed on fresh and partially converted chars to quantify the effect of CO2 partial pressure on pore development. It was found that pores development more rapidly with conversion if the CO2 partial pressure is increased. This outcome has fundamental implications for the interpretations of gasification reaction kinetics. The term describing the total amount of active sites in the Langmuir Hinshelwood equation might not be constant at all partial pressures, and the possible impact of that is shown in this work. More work is required to further understand these effects and incorporate them appropriately into high pressure rate equations.

Pulverized fuel (pf) combustion in a boiler for power generation is by far the most common approach for the utilization of low rank coals. The properties of low rank coals (in particular, moisture and alkali content) mean that such an approach is often very inefficient, leading to very high CO2 emissions. Low rank coals, however, are inexpensive, and in some regions represent a significant energy resource. This chapter discusses some of the advanced, high efficiency technologies that are being demonstrated or which are under development, which allow low rank coals to play a role in a low-carbon energy future. The chapter discusses the role of gasification in enabling low rank coals to be used for low emissions power or the production of chemicals, fertilizers, or hydrogen. It also gives an overview of emerging technologies, such as Direct Injection Carbon Engines, and those under development, such as Direct Carbon Fuel Cells.

This chapter was originally published in the book Advances in Applied Microbiology, Vol 65, published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who know you, and providing a copy to your institution’s administrator.

The goal of the Rialto project at Microsoft Research is to build a system architecture supporting coexisting independent real-time (and non-real-time) programs. Unlike traditional embedded-systems real-time environments, where timing and resource analysis among competing tasks can be done off-line, it is our goal to allow multiple independently authored real-time applications with varying timing and resource requirements to dynamically coexist and cooperate to share the limited physical resources available to them, as well as also coexisting with non-real-time applications.This paper gives an overview of the Rialto real-time architecture as it is implemented today and reports on some of the early results obtained. In particular, it describes the use of time constraints, activities, CPU and other resource reservation, and the system resource planner, and how they work together to achieve our goal of providing a flexible, dynamic real-time computing environment.

Publisher Summary This chapter presents an interdisciplinary approach to the molecular mechanisms of calmodulin action. The VU-1 calmodulin has an amino acid sequence that is a hybrid of vertebrate and plant calmodulins. The bacterially expressed protein lacks two of the post-translational modifications common to vertebrate and some other calmodulins. These include the acetylation of the amino terminus and the trimethylation of lysine-115. Apart from the lack of acetylation, the changes in the VU-1 calmodulin structure have been observed in the naturally occurring calmodulins. The study of calmodulin-activated proceses by protein engineering requires structural information about specific target enzymes. The detailed studies have focused on the calmodulin dependent enzyme Myosin Light Chain Kinase (MLCK). The amino acid sequences of potential calmodulin binding sites have been elucidated for skeletal and smooth muscle MLCK. A new calmodulin expression vector that allows for mutagenesis, amplification, characterization and expression of mutant calmodulin genes in E. coli has been constructed. The new expression vector, pVUCH-1, is a hybrid of pVUC-1 and pUC8. The orientation of the gene relative to the tac promoter elements within the plasmid is the same as that found in pVUC-1.

Publisher Summary This chapter discusses how synthetic oligonucleotides are used in studies of calmodulin and related calcium-binding proteins. The focus is on two specific applications of synthetic oligonucleotides: site-specific mutagenesis and detection of recombinant DNA vectors containing DNA inserts coding for calmodulin-like structures. The database of information on the phylogeny and ontogeny of calmodulin provides the necessary background for the initiation of studies utilizing a direct approach to structure and function that combines recombinant DNA, comparative enzymology, and protein chemistry techniques. The synthetic calmodulin gene was designed for mutagenesis by two approaches: cassette-based and M13-based mutagenesis. Mutagenesis is performed on a construction consisting of the synthetic calmodulin gene cloned in the EcoRI and BamHI sites of pUC8. Once the mutant calmodulin gene sequence is generated and verified, an expression vector containing the mutated gene sequences is constructed. Calmodulin mutant genes are expressed by cloning on the expression plasmid pKK223-3. The final purified product is characterized by a variety of analytical techniques including SDS-polyacrylamide gel electrophoresis, amino acid composition analyses of acid hydrolysates of the whole protein and selected peptide fractions, and limited amino acid sequence analyses.