New trends in neoadjuvant therapy of locally advanced rectal cancer from a surgeons perspective - a commentary.

BACKGROUND: Rectal cancer treatment advanced rapidly during last decades. The most important factors of this progress are new neoadjuvant therapy options, improvement in imaging (allowing for quality staging and restaging) and routine implementation of the total mesorectal excision technique. For the best outcomes, it is crucial to combine the treatment methods in the best way possible with ideal timing. It is necessary to keep in mind both advantages and complications of the individual kinds of approach. Therefore, interdisciplinary agreement is essential in the treatment of rectal cancer. Considering these new therapeutic possibilities, the debate about timing, indication and radicality of the surgical procedures is reopened. Surgical approaches are currently focused on mini-invasive methods and robotic surgery. New trend with promising potential seems to be clinical complete response achievement with watch and wait follow-up strategy. This approach, in the spirit of the organ sparing philosophy, however asks new questions about indication, timing and conception of this method. Proper answers are essential for sparing, yet radical oncotherapy of this disease.

Evaluation of Thermally Induced Degradation of Branched Polypropylene by Using Rheology and Different Constitutive Equations.

In this work, virgin as well as thermally degraded branched polypropylenes were investigated by using rotational and Sentmanat extensional rheometers, gel permeation chromatography and different constitutive equations. Based on the obtained experimental data and theoretical analysis, it has been found that even if both chain scission and branching takes place during thermal degradation of the tested polypropylene, the melt strength (quantified via the level of extensional strain hardening) can increase at short degradation times. It was found that constitutive equations such as Generalized Newtonian law, modified White-Metzner model, Yao and Extended Yao models have the capability to describe and interpret the measured steady-state rheological data of the virgin as well as thermally degraded branched polypropylenes. Specific attention has been paid to understanding molecular changes during thermal degradation of branched polypropylene by using physical parameters of utilized constitutive equations.