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Studies of a lattice model of water confined in a slit pore

Proposed for publication in an invited special edition of the Journal of Physical Chemistry.

Van Swol, Frank

We describe an extension of the Bell-Salt lattice model of water to the study of water confined in a slit pore. Wall-fluid interactions are chosen to be qualitatively representative of water interacting with a graphite surface. We have calculated the bulk vapor-liquid phase coexistence for the model through direct Monte Carlo simulations of the vapor-liquid interface. Adsorption and desorption isotherms in the slit pore were calculated using grand canonical ensemble Monte Carlo simulations. In addition, the thermodynamic conditions of vapor-liquid equilibrium for the confined fluid were determined. Our results are consistent with recent calculations for off-lattice models of confined water that show metastable vapor states of confined water persisting beyond the bulk saturation conditions, except for the narrowest pores. The results are similarly consistent with recent experiments on water adsorption in graphitized carbon black.

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Characterization of differentiated quiescent and nonquiescent cells in yeast stationary-phase cultures

Molecular Biology of the Cell

Aragon, Anthony D.; Rodriguez, Angelina L.; Meirelles, Osorio; Roy, Sushmita; Davidson, George S.; Tapia, Phillip H.; Allen, Chris; Joe, Ray; Benn, Don; Werner-Washburne, Margaret

Cells in glucose-limited Saccharomyces cerevisiae cultures differentiate into quiescent (Q) and nonquiescent (NQ) fractions before entering stationary phase. To understand this differentiation, Q and NQ cells from 101 deletion-mutant strains were tested for viability and reproductive capacity. Eleven mutants that affected one or both phenotypes in Q or NQ fractions were identified. NQ fractions exhibit a high level of petite colonies, and nine mutants affecting this phenotype were identified. Microarray analysis revealed >1300 mRNAs distinguished Q from NQ fractions. Q cell-specific mRNAs encode proteins involved in membrane maintenance, oxidative stress response, and signal transduction. NQ-cell mRNAs, consistent with apoptosis in these cells, encode proteins involved in Ty-element transposition and DNA recombination. More than 2000 protease-released mRNAs were identified only in Q cells, consistent with these cells being physiologically poised to respond to environmental changes. Our results indicate that Q and NQ cells differentiate significantly, with Q cells providing genomic stability and NQ cells providing nutrients to Q cells and a regular source of genetic diversity through mutation and transposition. These studies are relevant to chronological aging, cell cycle, and genome evolution, and they provide insight into complex responses that even simple organisms have to starvation. © 2008 by The American Society for Cell Biology.

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Results 77051–77075 of 96,771
Results 77051–77075 of 96,771