Biomedical subjects

Somendra M Bhattacharjee

Publications and source records attributed to Somendra M Bhattacharjee.

4 recordsLinked to original sources

PubMed2005

Unzipping an adsorbed polymer in a dirty or random environment.

The phase diagram of unzipping of an adsorbed directed polymer in two dimensions in a random medium has been determined. Both the hard-wall and the soft-wall cases are considered. Exact solutions for the pure problem with different affinities on the two sides are given. The results obtained by the numerical procedure adopted here are shown to agree with the exact results for the pure case. The characteristic exponents for unzipping for the random problem are different from the pure case. The distribution functions for the unzipped length, first bubble, and the spacer are determined.

Journal Article↗

PubMed2005

Force-induced triple point for interacting polymers.

We show the existence of a force induced triple point in an interacting polymer problem that allows two zero-force thermal phase transitions. The phase diagrams for two different models of mutually attracting but self-avoiding polymers are presented. One of these models has an intermediate phase and it shows a triple point. A general phase diagram with multicritical points in an extended parameter space is also discussed.

Journal Article↗

PubMed2004

Complete phase diagram of DNA unzipping: eye, Y fork, and triple point.

We study the unzipping of double stranded DNA by applying a pulling force at a fraction s (0< or =s < or =1) from the anchored end. From exact analytical and numerical results, the complete phase diagram is presented. The phase diagram shows a strong ensemble dependence for various values of s. In addition, we show the existence of an eye phase and a triple point.

DNA↗

PubMed2001

Dynamical scaling of the DNA unzipping transition.

We report studies of the dynamics of a set of exactly solvable lattice models for the force-induced DNA unzipping transition. Besides yielding the whole equilibrium phase diagram, which reveals a reentrance, these models enable us to characterize the dynamics of the process starting from a nonequilibrium initial condition. The thermal melting of DNA displays a model dependent time evolution. On the contrary, the dynamical mechanism for the unzipping by force is very robust and the scaling behavior is independent of the details of the description and, hence, superuniversal.

DNA↗