Validation of functional state of coronary tandem lesions using computational flow dynamics

Functional lesion assessment for coronary tandem lesions and its clinical applications have not been thoroughly studied. The aim of this study was to test the hypothesis that the fractional flow reserve (FFR) gradient across an individual stenosis (ΔFFR) during pressure-wire pullback is a surrogate of the relative functional severity of each stenosis in coronary tandem lesions. For in vitro validation, computational flow dynamic modeling of coronary tandem lesion with various degree of stenosis was constructed. For clinical validation, a total of 52 patients (104 lesions) with coronary tandem lesions (2 stenoses along 1 coronary artery) were consecutively enrolled, and tailored stent procedures based on ΔFFR was performed, at first treating the lesion with large ΔFFR and then subsequently reassessing the FFR for the remaining lesion. The coronary stenosis was considered functionally significant and stenting was performed when the FFR of a lesion was ≤0.80. Using in vitro computational flow dynamic modeling, the lesion with the large ΔFFR of the coronary tandem lesion was indicated as the lesion with the greater degree of simulated diameter stenosis. In the clinical cohort, 28 patients (53.8%) had only single-lesion treatment, and stent implantation for 28 lesions (26.9%) was deferred according to the proposed strategy. During the 9-month follow-up period, only 1 repeat revascularization occurred among the deferred lesions. In conclusion, for the treatment of coronary tandem lesions, ΔFFR may be a useful index for prioritizing the treatment sequence and optimizing the stenting procedure. In this way, unnecessary stent implantation can be avoided, with the achievement of favorable functional and clinical outcomes

Production of charged pions, kaons and protons at large transverse momenta in pp and Pb–Pb collisions at sNN=2.76\sqrt{s_{NN}}=2.76 TeV

Transverse momentum spectra of pi(+/-), K-+/- and p((p) over bar) up to p(T) = 20 GeV/c at mid-rapidity in pp, peripheral (60-80%) and central (0-5%) Pb-Pb collisions at v root s(NN) = 2.76 TeV have been measured using the ALICE detector at the Large Hadron Collider. The proton-to-pion and the kaon-to-pionratios both show a distinct peak at p(T) approximate to 3 GeV/c in central Pb-Pb collisions. Below the peak, p(T) 10 GeV/c particle ratios in pp and Pb-Pb collisions are in agreement and the nuclear modification factors for pi(+/-), K-+/- and p((p) over bar) indicate that, within the systematic and statistical uncertainties, the suppression is the same. This suggests that the chemical composition of leading particles from jets in the medium is similar to that of vacuum jets

Centrality dependence of the pseudorapidity density distribution for charged particles in Pb\u2013Pb collisions at 1asNN = 2.76 TeV

We present the first wide-range measurement of the charged-particle pseudorapidity density distribution, for different centralities (the 0\u20135%, 5\u201310%, 10\u201320%, and 20\u201330% most central events) in Pb\u2013Pb collisions at 1asNN = 2.76 TeV at the LHC. The measurement is performed using the full coverage of the ALICE detectors, 125.0 < \u3b7 < 5.5, and employing a special analysis technique based on collisions arising from LHC \u2018satellite\u2019 bunches. We present the pseudorapidity density as a function of the number of participating nucleons as well as an extrapolation to the total number of produced charged particles (Nch = 17 165 \ub1 772 for the 0\u20135% most central collisions). From the measured dNch/d\u3b7 distribution we derive the rapidity density distribution, dNch/dy, under simple assumptions. The rapidity density distribution is found to be significantly wider than the predictions of the Landau model. We assess the validity of longitudinal scaling by comparing to lower energy results from RHIC. Finally the mechanisms of the underlying particle production are discussed based on a comparison with various theoretical models

Centrality, rapidity and transverse momentum dependence of J/\u3c8 suppression in Pb-Pb collisions at 1asNN= 2.76TeV

The inclusive J/.nuclear modification factor (R-AA) in Pb-Pb collisions at root(NN)-N-S = 2.76TeVhas been measured by ALICE as a function of centrality in the e+ e-decay channel at mid-rapidity (| y| < 0.8) and as a function of centrality, transverse momentum and rapidity in the + -decay channel at forward-rapidity (2.5 < y < 4). The J/.yields measured in Pb-Pb are suppressed compared to those in ppcollisions scaled by the number of binary collisions. The RAAintegrated over a centrality range corresponding to 90% of the inelastic Pb-Pb cross section is 0.72 - 0.06(stat.) - 0.10(syst.) at mid-rapidity and 0.58 - 0.01(stat.) - 0.09(syst.) at forward-rapidity. At low transverse momentum, significantly larger values of RAAare measured at forward-rapidity compared to measurements at lower energy. These features suggest that a contribution to the J/.yield originates from charm quark (re) combination in the deconfined partonic medium