Abstract

Mutators are cells with a higher rate of mutations than normalcells. These mutations are base pair substitutions – errors that creep inwhen the genome is being copied during cell division. Mutator cells arepresent in small amounts in natural populations of some bacteria. Some kindsof cancer cells are also known to be mutators. A high mutation rate isusually a disadvantage but sometimes can also be an advantage to thespecies. In this talk, I will present my results on a simple model thattries to capture the evolutionary dynamics of mutator and normal cells. Ourmodel incorporates the conversion of normal cells to mutators and thereduction of fitness due to mutation. The mutators have a higher selectionpressure since a high mutation rate reduces fitness. The interplay ofconversion and the reduced fitness leads to an interesting phase diagram. Wehave predicted a new, all-mutator phase and calculated the phase transitionpoint analytically.

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Abstract

The modern device concepts have triggered an interesting scientific searchfor new multifunctional materials with novel set of physical properties.One of the scientifically challenging and technologically rewardingapproaches is to explore the possibilities of inducing new novelfunctionalities by incorporating foreign elements either via energeticions or chemically, thereby harnessing the benefits of both intrinsic andextrinsic properties. Alloying, interface, imperfection and dimensionalityplay critical roles in the manipulation process leading to unexpectedcatalysis processes inside solids, magnetic properties without anymagnetic element, thermal conductivities, electronic phase separation andtransports. In this talk, I will summarize and discuss the results of anumber of studies carried out on different elemental semiconductors, wideband gap oxides and layered structure materials.

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