Decoupling of non-strange, strange and multi-strange particles from the system in Cu-Cu, Au-Au and Pb-Pb collisions at high energies

Transverse momentum spectra of the non-strange, strange and multi-strange particles in central and peripheral Copper-Copper, Gold-Gold and Lead-Lead collisions are analyzed by the blast wave model with Boltzmann Gibbs statistics. The model results are approximately in agreement with the experimental data measured by BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations in special transverse momentum ranges. Bulk properties in terms of kinetic freeze out temperature, transverse flow velocity and freezeout volume are extracted from the transverse momentum spectra of the particles. Separate freeze out temperatures are observed for the non-strange, strange and multi-strange particles which maybe due to different reaction cross-sections of the interacting particles and it reveals the triple kinetic freezeout scenario in collisions at BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations, however the transverse flow velocity and freezeout volume are mass dependent and they decrease with the increasing the rest mass of the particles. Furthermore, the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume in central nucleus-nucleus collisions are larger than those in peripheral collisions. Besides, the larger kinetic freezeout temperature and freezeout volume are observed in the most heaviest nuclei collisions, indicating their dependence on the size of interacting syste

Histological study on the effect of transplanted human umbilical cord blood CD34+ stem cells on albino rats subjected to myocardial infarction

Background: Heart failure is a significant burden to health care systems in the world. One of its major causes is myocardial infarction (MI). Recent developments in stem cells may offer ways to manage heart failure by replacing damaged cardiac muscle with healthy tissue. This study aimed at examining the regenerative effect of intravenously transplanted human umbilical cord blood CD34+ stem cell in a rat model of acute MI. Methods: Forty adult female rats were equally randomized into 5 groups. Groups I and II received saline alone or saline followed by isolation buffer respectively to serve as control groups. The other 3 groups were subjected to induction of acute MI using subcutaneous injection of isoprenaline hydrochloride. In groups III and IV, animals were sacrificed after one week and four weeks respectively. One week after induction of MI, animals in group V received intravenous injection of 4 x 106 CD34+ stem cells separated from the human umbilical cord blood of male fetuses, and were sacrificed after 3 weeks from cell injection. At the end of the experiment, heart tissue was processed for both light and electron microscopic histological studies, and for PCR analysis of the male-specific SRY gene. Results: Light microscopic results of group III revealed increased diameter and necrosis of cardiomyocytes, decreased cross-striations, vascular congestion and mononuclear cellular infiltration. Group IV revealed multiple extensive fibrotic areas. Group V revealed smaller fibrotic areas compared to Group IV. Ultrastructural results confirmed findings of the light microscope. PCR analysis revealed that 63% of heart samples were positive for the presence of SRY gene. Conclusion: CD34+ stem cells can transdifferentiate into cardiomyocyte and regenerate the injured heart subjected to MI.Keywords: HUCB, CD34+ stem cells, myocardial infarction, transdifferentiatio

Search for a Signal on QCD Critical Point in Central Nucleus-Nucleus Collisions

We discuss that the QCD critical point could appear in central collisions in percolation cluster. We suggest using the nuclear transparency effect and the one of the light nuclear production to identify the critical point.Comment: To appear in the proceedings of the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2008), Jaipur, India, February 4-10, 200