77 research outputs found

    Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

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    A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

    A Design Checking Tool Based on Aesthetic Properties from Design Theories of Architecture: Focused on Musical Harmony in Architecture

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    This paper proposes a way how a semantic aesthetic property from architectural theories in the Western world can be integrated into a computer-aided architectural design (CAAD) system. It starts from the premise that computer-aided design tools are mostly aimed at serving as drawing tools which are used only after a design formal solution has already been established by the architect. To support an early design solution in a computer-based environment, a design checking tool was developed and tested in a real building project. This tool gives various design alternatives from the early design phase to the final stage of design details, according to musical harmony. Finally, this paper shows that an aesthetic property from architectural theories can be calculated with the aid of a computerbased design tool, and the used tool played its role as a design assistant in supporting the architectural design

    Developmental changes in rat cardiac DNA, RNA and protein tissue base: implications for the interpretation of changes in gene expression

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    During cardiac development the expression levels of many genes change as determined by Northern blot, dot blot, RNase protection, quantitative RT-PCR. Western blot or immunoprecipitation analyses. It is not always realized that the total amount of RNA or protein per gram of heart, dubbed tissue base, may change significantly during development as well. If this would be the case, this has to be taken into account. So far, the (changing) tissue base has not been established during cardiac development. To this end developmental profiles of cardiac DNA, RNA and protein concentration were determined in rats ranging in age from embryonic day 13 until neonatal day 121. The profiles show significant development changes in each parameter, that closely match the distinct growth phases of the developing heart and provide the parameters that are essential for an adequate interpretation of changes in the amount of a distinct mRNA and/or protein. In a comparison between in situ hybridization and Northern blot analysis it is demonstrated that the same developmental profile leads to an almost opposite conclusion depending on whether or not the changing tissue base is taken into account. These findings are of great interest for studies aimed at unravelling the molecular mechanisms underlying the regulation of gene expression during cardiac developmen

    Uncoupling of S phase and mitosis in cardiomyocytes and hepatocytes lacking the winged-helix transcription factor Trident

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    In order to maintain a stable karyotype, the eukaryotic cell cycle is coordinated such that only one round of S phase precedes each mitosis, and mitosis is not initiated until DNA replication is completed. Several checkpoints and regulatory proteins have been defined in lower eukaryotes that govern this coordination, but little is known about the proteins that are involved in mammalian cells. Previously, we have shown that the winged-helix transcription factor Trident - also known as HFH-11, FKL16 and WIN [1] [2] [3] - is exclusively expressed in cycling cells and is phosphorylated during mitosis [1] [4]. The cellular function of Trident has yet to be described, however. Here, we have shown that disruption of the Trident gene in mice resulted in postnatal death, most probably because of circulatory failure. Histological analysis of Trident -/- embryos from embryonic day 10 (E10) onwards revealed a specific, characteristic defect in the developing myocardium. The orientation of the myocytes was highly irregular and the nuclei of these disorganized cardiomyocytes were clearly polyploid with up to a 50-fold increase in DNA content. Polyploidy was also observed in embryonic hepatocytes. Our results indicate that expression of Trident is required to prevent multiple rounds of S phase in the heart and the liver. Trident therefore appears to have a role in preventing DNA re-replication during the G2 and M phases
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