Visečestične korelacije sivih čestica emitiranih u sudarima jezgra–jezgra

The short range correlation among emitted knock on nucleons from heavy ion collisions is used to reveal the dynamic characteristics of the reactions at high energy. Two- and three-particle correlations are considered in angular space to explain the emission of gray particles from collectively excited states of the nucleus as a Fermi liquid drop. Positive correlation is detected only among particles emitted in the extreme backward direction which is the coldest domain. It is interpreted as direct non-statistical emission (splashing) of nucleons via the dynamical distortion of the Fermi surface accompanying the collective motion.Proučavamo korelacije kratkog dosega izbijenih nukleona u sudarima teških iona radi upoznavanja dinamičkih značajki tih reakcija na visokim energijama. Razmatramo dvo- i tro-čestične kutne korelacije emitiranih sivih čestica iz kolektivnih uzbudnih stanja jezgre promatrane kao Fermijeva kapljica tekućine. Pozitivna se korelacija opaža samo u smjeru prema natrag što odgovara najhladnijem području jezgre. To se tumači kao izravna nestatistička emisija (zapljuskivanje) nukleona putem dinamičkog izobličenja Fermijeve površine pri kolektivnom gibanju u jezgri

Visečestične korelacije sivih čestica emitiranih u sudarima jezgra–jezgra

The short range correlation among emitted knock on nucleons from heavy ion collisions is used to reveal the dynamic characteristics of the reactions at high energy. Two- and three-particle correlations are considered in angular space to explain the emission of gray particles from collectively excited states of the nucleus as a Fermi liquid drop. Positive correlation is detected only among particles emitted in the extreme backward direction which is the coldest domain. It is interpreted as direct non-statistical emission (splashing) of nucleons via the dynamical distortion of the Fermi surface accompanying the collective motion.Proučavamo korelacije kratkog dosega izbijenih nukleona u sudarima teških iona radi upoznavanja dinamičkih značajki tih reakcija na visokim energijama. Razmatramo dvo- i tro-čestične kutne korelacije emitiranih sivih čestica iz kolektivnih uzbudnih stanja jezgre promatrane kao Fermijeva kapljica tekućine. Pozitivna se korelacija opaža samo u smjeru prema natrag što odgovara najhladnijem području jezgre. To se tumači kao izravna nestatistička emisija (zapljuskivanje) nukleona putem dinamičkog izobličenja Fermijeve površine pri kolektivnom gibanju u jezgri

Facile Synthesis Of Reduced Graphene Oxide-supported Pd/Cuo Nanoparticles As An Efficient Catalyst For Cross-coupling Reactions

The present communication reports a scientific investigation of a simple and versatile synthetic route for the synthesis of palladium nanoparticles decorated with copper oxide and supported on reduced graphene oxide (rGO). They are used as a highly active catalyst of Suzuki, Heck, and Sonogashira cross coupling reactions with a remarkable turnover number of 7000 and a turnover frequency of 85000 h-1. The Pd-CuO nanoparticles supported on reduced graphene oxide nanosheets (Pd-CuO/rGO) exhibit an outstanding performance through a high catalytic activity towards cross coupling reactions. A simple, reproducible, and reliable method is used to prepare this efficient catalyst using microwave irradiation synthetic conditions. The synthesis approach requires a simultaneous reduction of palladium and copper nitrates in presence of graphene oxide (GO) nanosheets using hydrazine hydrate as a strong reducing agent. The highly active and recyclable catalyst has many advantages including mild reaction conditions and short reaction durations in an environmentally benign solvent system. Moreover, the catalyst prepared can be recycled for up to five times with nearly identical high catalytic activity. Furthermore, the high catalytic activity and the recyclability of the catalyst prepared are due to the strong catalyst-support interaction. The defect sites of the reduced graphene oxide (rGO) act as nucleation centers that enable anchoring of both Pd and CuO nanoparticles and hence, minimize the possibility of agglomeration which leads to a severe decrease of the catalytic activity

Microwave-assisted Synthesis Of Palladium Nanoparticles Supported On Copper Oxide In Aqueous Medium As An Efficient Catalyst For Suzuki Cross-coupling Reaction

We report here a reliable green method for the synthesis of palladium nanoparticles supported on copper oxide as a highly active and efficient catalyst for Suzuki cross-coupling reaction. The experimental synthetic approach is based on microwave-assisted chemical reduction of an aqueous mixture of palladium and copper salt simultaneously using hydrazine hydrate as reducing agent. The catalyst was fully characterized using various techniques showing well-dispersed palladium nanoparticles. The catalytic activity and recyclability of the prepared catalyst were experimentally explored in the ligand-free Suzuki cross-coupling reaction with a diverse series of functionalized substrates. The synthesized Pd/CuO catalyst shows many advantages beside its high catalytic efficiency such as the recyclability of up to five times with negligible loss of catalytic activity, short reaction times, use of environmentally benign solvent systems, and mild reaction conditions

Congenital coronary artery anomalies in adult population detected using dual source ECG-gated CTA in a single institution

Background: Congenital anomalies of the coronary arteries (CAs) are rare and are often diagnosed incidentally during a conventional coronary angiography. Recently, the incidence of these congenital defects is on the rise particularly after the introduction of the electrocardiography (ECG) gated coronary computed tomographic angiography (CCTA). This innovative radiological screening modality has led to the most precise mapping of the course of the CAs on computed tomographic scan. The aim of the study is to determine the prevalence and describe the CAs congenital anomalies and their variations in Kuwaiti population at a single institution experience. Materials and methods: We analysed the CCTA data obtained consecutively from 842 patients (2013–2014), retrospectively. The inclusion criteria for patients’ selection were: atypical chest pain, equivocal ECG, assessment of patency of coronary stents or grafts and pre-operative screening. Information was acquiesced using a dual-source CT scanner with ECG gating. Results: Data analysis revealed that 22 (2.61%) patients were found to have CA anomalies out of the 842 patients who underwent CCTA. Out of these CA anomalies, 13 cases showed more than two ostia, 7 cases showed the ectopic origin of a CA from opposite sinus or non-aortic sinus, 2 cases showed single coronary ostium and 1 case showed coronary artery with pulmonary fistula. Also, myocardial bridging was identified in 78 (9.26%) patients whereas ramus intermedius branch was identified in 160 (19%) patients. Conclusions: The prevalence of CA anomalies in Kuwait was 2.6%, which is relatively higher than previously reported studies from different countries

Redox Regulation of Heart Regeneration: An Evolutionary Tradeoff

Heart failure is a costly and deadly disease, affecting over 23 million patients worldwide, half of which die within 5 years of diagnosis. The pathophysiological basis of heart failure is the inability of the adult heart to regenerate lost or damaged myocardium. Although limited myocyte turnover does occur in the adult heart, it is insufficient for restoration of contractile function1-6. In contrast to lower vertebrates which can regenerate their myocardium through cardiomyocyte proliferation,7-13, adult mammalian heart cardiomyogenesis very limited1-5. Studies in the late 90s elegantly demonstrated that mammalian cardiomyocytes continue to divide for a few days after birth 14-16, only to undergo permanent cell cycle arrest shortly thereafter. Recently, we demonstrated that resection of up to 15% of the apex of the left ventricle of postnatal day 1 (P1) mice results in complete regeneration within 21 days following injury, without significant fibrosis and cardiac dysfunction17. Moreover, we described a similar regenerative response following ischemic myocardial infarction 18. This response was well characterized by robust cardiomyocyte proliferation, with gradual restoration of normal cardiac morphology and function. In addition to the histological evidence of proliferating myocytes, genetic fate-mapping studies confirmed that the majority of newly formed cardiomyocytes are derived from proliferation of preexisting cardiomyocytes17. Intriguingly, this regenerative capacity is lost by P7, after which injury results in the cardiomyocyte hypertrophy and scar-formation, which coincides with binucleation and cell cycle exit of cardiomyocytes 14, 19. An important approach to understanding the loss of regenerative ability of the mammalian heart is to first consider why, and not only how, this happens. The regenerative ability of the early postnatal heart following resection or ischemic infarction involves regeneration of the lost myocardium and vasculature with restoration of normal myocardial thickness and architecture, and long-term functional recovery. Why would the heart permanently forego such a remarkable regenerative program shortly after birth? The answer may lie in within the fundamental principal of evolutionary tradeoff

Mass Hierarchies and the Seesaw Neutrino Mixing

We give a general analysis of neutrino mixing in the seesaw mechanism with three flavors. Assuming that the Dirac and u-quark mass matrices are similar, we establish simple relations between the neutrino parameters and individual Majorana masses. They are shown to depend rather strongly on the physical neutrino mixing angles. We calculate explicitly the implied Majorana mass hierarchies for parameter sets corresponding to different solutions to the solar neutrino problem.Comment: 11 pages, no figures, replaced with final version. Minor corrections and one typo corrected. Added one referenc