Cardiomyocyte generation from somatic sources — current status and future directions

Transdifferentiation of one cell type to another has garnered significant research efforts in recent years. As cardiomyocyte loss following myocardial infarction becomes debilitating for cardiac patients, the option of an autologous source of cardiomyocytes not derived from multi/pluripotent stem cell sources is an attractive option. Such direct programming has been clearly realized with the use of transcription factors, microRNAs and more recently small molecule delivery to enhance epigenetic modifications, all albeit with low efficiencies in vitro. In this review, we aim to present a brief overview of the current in vitro and in vivo transdifferentiation strategies in the generation of cardiomyocytes from somatic sources. The interdisciplinary fields of tissue, cell, material and regenerative engineering offer many opportunities to synergistically achieve directly programmed cardiac tissue in vitro and enhance transdifferentiation in vivo. This review aims to present a concise outlook on this topic with these fields in mind

Memory effects in radiative jet energy loss

In heavy-ion collisions the created quark-gluon plasma forms a quickly evolving background, leading to a time dependent radiative behavior of high momentum partons traversing the medium. We use the Schwinger Keldysh formalism to describe the jet evolution as a non-equilibrium process including the Landau-Pomeranschuk-Migdal effect. Concentrating on photon emission, a comparison of our results to a quasistatic calculation shows good agreement, leading to the conclusion that the radiative behavior follows the changes in the medium almost instantaneously

Angular-ordered parton showers with medium-modified splitting functions

Modified Altarelli-Parisi splitting functions were recenty proposed to model multi-parton radiation in a dense medium and describe jet quenching, one of most striking features of heavy-ion collisions. We implement medium-modified splitting functions in the HERWIG parton shower algorithm, which satisfies the angular ordering prescription, and present a few parton-level results, such as transverse momentum, angle and energy-fraction distributions, which exhibit remarkable medium-induced effects. We also comment on the comparison with respect to the results yielded by other implementations of medium-modified splitting functions in the framework of virtuality-ordered parton cascades.Comment: 19 pages, 8 figures, 1 table. Minor changes after referee repor

VISHNU hybrid model for viscous QCD matter at RHIC and LHC energies

In this proceeding, we briefly describe the viscous hydrodynamics + hadron cascade hybrid model VISHNU for relativistic heavy ion collisions and report the current status on extracting the QGP viscosity from elliptic flow data.Comment: 4 pages, 1 figure, the proceedings of 7th International Workshop on Critical Point and Onset of Deconfinement, Wuhan, China, Nov. 7-11, 201

What does the rho-meson do? In-medium mass shift scenarios versus hadronic model calculations

The NA60 experiment has studied low-mass muon pair production in In-In collisions at $158 {\rm AGeV}$ with unprecedented precision. With these results there is hope that the in-medium modifications of the vector meson spectral function can be constrained more thoroughly than before. We investigate in particular what can be learned about collisional broadening by a hot and dense medium and what constrains the experimental results put on in-medium mass shift scenarios. The data show a clear indication of considerable in-medium broadening effects but disfavor mass shift scenarios where the $\rho$-meson mass scales with the square root of the chiral condensate. Scaling scenarios which predict at finite density a dropping of the $\rho$-meson mass that is stronger than that of the quark condensate are clearly ruled out since they are also accompanied by a sharpening of the spectral function.Comment: Proceeding contribution, Talk given by J. Ruppert at Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions (Hot Quarks 2006), Villasimius, Sardinia, Italy, 15-20 May 2006. To appear in EPJ