Elliptic and triangular flow in p-Pb and peripheral Pb-Pb collisions from Parton scatterings.

Using a multiphase transport model (AMPT) we calculate the elliptic v_{2} and triangular v_{3} Fourier coefficients of the two-particle azimuthal correlation function in proton-nucleus (p-Pb) and peripheral nucleus-nucleus (Pb-Pb) collisions. Our results for v_{3} are in a good agreement with the CMS data collected at the Large Hadron Collider. The v_{2} coefficient is very well described in p-Pb collisions and is underestimated for higher transverse momenta in Pb-Pb interactions. The characteristic mass ordering of v_{2} in p-Pb is reproduced, whereas for v_{3}, this effect is not observed. We further predict the pseudorapidity dependence of v_{2} and v_{3} in p-Pb and observe that both are increasing when going from a proton side to a Pb-nucleus side. Predictions for the higher-order Fourier coefficients, v_{4} and v_{5}, in p-Pb are also presented.

Serum YKL-40 independently predicts outcome after transcatheter arterial chemoembolization of hepatocellular carcinoma.

BACKGROUND: Transcatheter arterial chemoembolization (TACE) is the most widely used treatment option for unresectable hepatocellular carcinoma (HCC). Elevated serum YKL-40 level has been shown to predict poor prognosis in HCC patients undergoing resection. This study was designed to validate the prognostic significance of serum YKL-40 in patients with HCC undergoing TACE treatment. METHODS: Serum YKL-40 level was determined by enzyme-linked immunosorbent assay. Overall survival (OS) was evaluated with the Kaplan-Meier method and compared by the log-rank test. Multivariate study with Cox proportional hazard model was used to evaluate independent prognostic variables of OS. RESULTS: The median pretreatment serum YKL-40 in HCC patients with was significantly higher than that in healthy controls (P<0.001). The YKL-40 could predict survival precisely either in a dichotomized or continuous fashion (P<0.001 and P = 0.001, respectively). Multivariate Cox regression analysis indicated that serum YKL-40 was an independent prognostic factor for OS in HCC patients (P = 0.001). In further stratified analyses, YKL-40 could discriminate the outcomes of patients with low and high alpha-fetoprotein (AFP) level (P = 0.006 and 0.016, respectively). Furthermore, the combination of serum YKL-40 and AFP had more capacity to predict patients' outcomes. CONCLUSIONS: Serum YKL-40 was demonstrated to be an independent prognostic biomarker in HCC patients treated with TACE. Our results need confirmation in an independent study.

Elevated serum YKL-40 level predicts poor prognosis in hepatocellular carcinoma after surgery.

BACKGROUND: YKL-40 is a member of the mammalian chitinase-like proteins. Elevated serum YKL-40 levels in patients with gastrointestinal cancer at time of diagnosis are associated with poor prognosis. The aim of this study is to evaluate the prognostic value of serum YKL-40 before surgery and during follow-up in hepatocellular carcinoma (HCC) patients receiving curative resection. METHODS: Serum YKL-40 levels were determined by enzyme-linked immunosorbent assay. Overall and recurrence-free survival (RFS) curves were constructed using the Kaplan-Meier method and compared by the log-rank test. A Cox proportional-hazards regression model was performed to identify independent prognostic factors. Median follow-up time was 35 months. RESULTS: Baseline serum YKL-40 was elevated in 56% of patients with HCC receiving curative resection. Patients with elevated serum YKL-40 had significantly shorter overall and RFS than patients with normal serum YKL-40 (P = 0.003 and P = 0.001, respectively). Multivariate Cox regression analyses indicated that baseline serum YKL-40 was an independent prognostic variable for overall and RFS [hazard ratio (HR) = 1.968, 95% confidence interval (CI): 1.093-3.543, P = 0.024; HR = 1.891, 95% CI: 1.106-3.232, P = 0.020; respectively]. After curative resection, high serum YKL-40 (log-transformed continuous variable) within 6 months predicted significantly poorer overall survival (HR = 3.003, 95% CI: 1.323-6.817, P = 0.009). CONCLUSIONS: This study indicated that serum YKL-40 was an independent prognostic factor for overall and RFS in HCC patients receiving curative resection. Serial monitoring of serum YKL-40 after curative resection may provide prognostic information.

Jets, Mach cones, hot spots, ridges, harmonic flow, dihadron, and γ-hadron correlations in high-energy heavy-ion collisions.

Within the AMPT Monte Carlo model, fluctuations in the initial transverse parton density are shown to lead to harmonic flows. The net back-to-back dihadron azimuthal correlation after subtraction of contributions from harmonic flows still has a double peak that is independent of the initial geometric triangularity and unique to the jet-induced Mach cone and expanding hot spots distorted by radial flow. The longitudinal structure of hot spots also leads to a nearside ridge in dihadron correlation with a large rapidity gap. By successively randomizing the azimuthal angle of the transverse momenta and positions of initial partons, one can isolate the effects of jet-induced medium excitation and expanding hot spots on the dihadron azimuthal correlation. The double peaks in the net dihadron and γ-hadron correlation are quantitatively different since the later is caused only by jet-induced Mach cone.

Mach cone induced by γ-triggered jets in high-energy heavy-ion collisions.

Medium excitation by jet shower propagation inside a quark-gluon plasma is studied within a linear Boltzmann transport and a multiphase transport model. Contrary to the naive expectation, it is the deflection of both the jet shower and the Mach-cone-like excitation in an expanding medium that is found to give rise to a double-peak azimuthal particle distribution with respect to the initial jet direction. Such a deflection is the strongest for hadron-triggered jets which are often produced close to the surface of a dense medium due to trigger bias and travel against or tangential to the radial flow. Without such trigger bias, the effect of deflection on γ-jet showers and their medium excitation is weaker. Comparative study of hadron and γ-triggered particle correlations can therefore reveal the dynamics of jet-induced medium excitation in high-energy heavy-ion collisions.