Variety of scaling laws for DNA thermal denaturation

We discuss possible mechanisms that may impact the order of transition between denaturated and bound DNA states lead to changes in scaling laws govern conformational properties strands. To this end, we re-consider Poland-Scheraga model apply a polymer field theory approach calculate entropic exponents associated with loop distribution. particular variants occur due solution affect self- mutual interaction both single double find effects studied significantly influence strength first transition. This is manifest by strand As quantitative measure these present values corresponding exponents. For $d=4-\varepsilon$ case get $\varepsilon^4$ expansions evaluate perturbation at space dimension $d=3$ means resummation technique.