Subsolidus phase equilibria of Fe-Ni-X-O (X = Mg, Al) systems in air

The phase equilibria of Fe-Ni-X-O (X = Mg, Al) systems, including their lower-order systems, at temperatures between 1200 C and 1600 C in air in the subsolidus region, have been experimentally studied. In the present study, the ‘Fe2O3’-MgO, ‘Fe2O3’-Al2O3, and NiO-Al2O3 binary phase diagrams, as well as the ternary phase diagrams in the Fe-Ni-Mg-O and Fe-Ni-Al-O systems projected onto the Fe-Mg-Ni and Fe-Al-Ni planes, have been constructed. Differences have been found between the present measurements, the previously published data, and the FactSage predictions, especially in the lower-order systems. It is suggested that the improved experimental techniques used in the present study, which involve carefully planned equilibration procedures followed by electron probe X-ray microanalyses (EPMA), provide more accurate and precise measurements of the phase boundaries and phase compositions

DNA-damage-induced checkpoint pathways in the nematode Caenorhabditis elegans.

Genomic instability is believed to be an enabling characteristic of cancer (Hanahan and Weinberg 2000).Therefore, it is not surprising that sophisticated mechanisms exist to maintain the integrity of the genome. Damage to DNA triggers checkpoint controls that result in cellcycle arrest and repair of the lesion (Nurse 1997, 2000;Weinert 1998). In multicellular organisms, when DNAdamage is extensive, these potentially harmful cells areeliminated by apoptosis (Enoch and Norbury 1995; Evanand Littlewood 1998). Defects in communications between DNA damage and the apoptotic program leads tothe survival of cells with unstable genomes vulnerable tooncogene activation, ultimately leading to tumor development (Morgan and Kastan 1997; Orr-Weaver andWeinberg 1998; Hanahan and Weinberg 2000). Geneticwork in yeast has greatly improved our understanding ofthe molecular mechanisms of DNA-damage-inducedcheckpoint arrest and repair. On the other hand, DNAdamage-induced apoptosis cannot be studied in yeasts, asthe apoptotic program is missing in both Saccharomycescerevisiae and Schizosaccharomyces pombe (Fraser andJames 1998)..