Net-charge fluctuations in Pb-Pb collisions at sqrt[sNN]=2.76 TeV

We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at sqrt[sNN]=2.76  TeV, measured with the ALICE detector at the CERN Large Hadron Collider. The dynamical fluctuations per unit entropy are observed to decrease when going from peripheral to central collisions. An additional reduction in the amount of fluctuations is seen in comparison to the results from lower energies. We examine the dependence of fluctuations on the pseudorapidity interval, which may account for the dilution of fluctuations during the evolution of the system. We find that the fluctuations at the LHC are smaller compared to the measurements at the BNL Relativistic Heavy Ion Collider, and as such, closer to what has been theoretically predicted for the formation of a quark-gluon plasma.

Transverse momentum distribution and nuclear modification factor of charged particles in p+Pb collisions at sqrt[s(NN)] = 5.02 TeV

The transverse momentum (p(T)) distribution of primary charged particles is measured in minimum bias (non-single-diffractive) p+Pb collisions at sqrt[s(NN)]=5.02 TeV with the ALICE detector at the LHC. The p(T) spectra measured near central rapidity in the range 0.5<p(T) <20 GeV/c exhibit a weak pseudorapidity dependence. The nuclear modification factor R(pPb) is consistent with unity for p(T) above 2 GeV/c. This measurement indicates that the strong suppression of hadron production at high p(T) observed in Pb+Pb collisions at the LHC is not due to an initial-state effect. The measurement is compared to theoretical calculations.

Pseudorapidity density of charged particles in p+Pb collisions at √(s(NN))=5.02 TeV

The charged-particle pseudorapidity density measured over four units of pseudorapidity in nonsingle-diffractive p+Pb collisions at a center-of-mass energy per nucleon pair √(s(NN))=5.02 TeV is presented. The average value at midrapidity is measured to be 16.81±0.71 (syst), which corresponds to 2.14±0.17 (syst) per participating nucleon, calculated with the Glauber model. This is 16% lower than in nonsingle-diffractive pp collisions interpolated to the same collision energy and 84% higher than in d+Au collisions at s√(s(NN))=0.2 TeV. The measured pseudorapidity density in p+Pb collisions is compared to model predictions and provides new constraints on the description of particle production in high-energy nuclear collisions.

Charge separation relative to the reaction plane in Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV

Measurements of charge-dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudorapidity range |η| < 0.8 are presented as a function of the collision centrality, particle separation in pseudorapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge-dependent azimuthal correlations observed at RHIC and LHC energies.

Pion, kaon, and proton production in central Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV

In this Letter we report the first results on π(±), K(±), p, and p production at midrapidity (|y|<0.5) in central Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV, measured by the ALICE experiment at the LHC. The p(T) distributions and yields are compared to previous results at sqrt[s(NN)] = 200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with sqrt[s(NN)], which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/π ratio is in line with predictions from the thermal model, the p/π ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood.

Measurement of the cross section for electromagnetic dissociation with neutron emission in Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV

The first measurement of neutron emission in electromagnetic dissociation of ^{208}Pb nuclei at the LHC is presented. The measurement is performed using the neutron zero degree calorimeters of the ALICE experiment, which detect neutral particles close to beam rapidity. The measured cross sections of single and mutual electromagnetic dissociation of Pb nuclei at sqrt[s(NN)]=2.76 TeV with neutron emission are σ(singleEMD)=187.4 ± 0.2(stat)(-11.2)(+13.2) (syst) b and σ(mutualEMD) = 5.7 ± 0.1(stat) ± 0.4(syst) b, respectively. The experimental results are compared to the predictions from a relativistic electromagnetic dissociation model.

Cold-nuclear-matter effects on heavy-quark production in d+Au collisions at sqrt[S(NN)]=200 GeV

The PHENIX experiment has measured electrons and positrons at midrapidity from the decays of hadrons containing charm and bottom quarks produced in d+Au and p+p collisions at sqrt[S(NN)]=200 GeV in the transverse-momentum range 0.85 ≤ p(T)(e) ≤ 8.5 GeV/c. In central d+Au collisions, the nuclear modification factor R(dA) at 1.5<p(T)<5 GeV/c displays evidence of enhancement of these electrons, relative to those produced in p+p collisions, and shows that the mass-dependent Cronin enhancement observed at the Relativistic Heavy Ion Collider extends to the heavy D meson family. A comparison with the neutral-pion data suggests that the difference in cold-nuclear-matter effects on light- and heavy-flavor mesons could contribute to the observed differences between the π(0) and heavy-flavor-electron nuclear modification factors R(AA).

Metabolomics of human intestinal transplant rejection

Surveillance endoscopy with biopsy is the standard method to monitor intestinal transplant recipients but it is invasive, costly and prone to sampling error. Early noninvasive biomarkers of intestinal rejection are needed. In this pilot study we applied metabolomics to characterize the metabolomic profile of intestinal allograft rejection. Fifty-six samples of ileostomy fluid or stool from 11 rejection and 45 nonrejection episodes were analyzed by ultraperformance liquid chromatography in conjunction with Quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS). The data were acquired in duplicate for each sample in positive ionization mode and preprocessed using XCMS (Scripps) followed by multivariate data analysis. We detected a total of 2541 metabolites in the positive ionization mode (mass 50-850 Daltons). A significant interclass separation was found between rejection and nonrejection. The proinflammatory mediator leukotriene E4 was the metabolite with the highest fold change in the rejection group compared to nonrejection. Water-soluble vitamins B2, B5, B6, and taurocholate were also detected with high fold change in rejection. The metabolomic profile of rejection was more heterogeneous than nonrejection. Although larger studies are needed, metabolomics appears to be a promising tool to characterize the pathophysiologic mechanisms involved in intestinal allograft rejection and potentially to identify noninvasive biomarkers.

Evolution of π(0) suppression in Au+Au collisions from √(s(NN))=39 to 200 GeV

Neutral-pion π(0) spectra were measured at midrapidity (|y|<0.35) in Au+Au collisions at √(s(NN))=39 and 62.4 GeV and compared with earlier measurements at 200 GeV in a transverse-momentum range of 1<p(T)<10 GeV/c. The high-p(T) tail is well described by a power law in all cases, and the powers decrease significantly with decreasing center-of-mass energy. The change of powers is very similar to that observed in the corresponding spectra for p+p collisions. The nuclear modification factors (R(AA)) show significant suppression, with a distinct energy, centrality, and p(T) dependence. Above p(T)=7 GeV/c, R(AA) is similar for √(s(NN))=62.4 and 200 GeV at all centralities. Perturbative-quantum-chromodynamics calculations that describe R(AA) well at 200 GeV fail to describe the 39 GeV data, raising the possibility that, for the same p(T) region, the relative importance of initial-state effects and soft processes increases at lower energies. The p(T) range where π(0) spectra in central Au+Au collisions have the same power as in p+p collisions is ≈5 and 7 GeV/c for √(s(NN))=200 and 62.4 GeV, respectively. For the √(s(NN))=39 GeV data, it is not clear whether such a region is reached, and the x(T) dependence of the x(T)-scaling power-law exponent is very different from that observed in the √(s(NN))=62 and 200 GeV data, providing further evidence that initial-state effects and soft processes mask the in-medium suppression of hard-scattered partons to higher p(T) as the collision energy decreases.

Measurement of direct photons in Au+Au collisions at √(s(NN))=200 GeV

We report the measurement of direct photons at midrapidity in Au+Au collisions at √(s(NN))=200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c<p(T)<22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R(AA) was calculated as a function of p(T) for different Au+Au collision centralities using the measured p+p direct photon spectrum and compared to theoretical predictions. R(AA) was found to be consistent with unity for all centralities over the entire measured p(T) range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R(AA) from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement.

Observation of direct-photon collective flow in Au + Au collisions at √s(NN)] = 200 GeV

The second Fourier component v(2) of the azimuthal anisotropy with respect to the reaction plane is measured for direct photons at midrapidity and transverse momentum (p(T)) of 1-12 GeV/c in Au + Au collisions at √s(NN)] = 200 GeV. Previous measurements of this quantity for hadrons with p(T) < 6 GeV/c indicate that the medium behaves like a nearly perfect fluid, while for p(T) > 6 GeV/c a reduced anisotropy is interpreted in terms of a path-length dependence for parton energy loss. In this measurement with the PHENIX detector at the Relativistic Heavy Ion Collider we find that for p(T) > 4 GeV/c the anisotropy for direct photons is consistent with zero, which is as expected if the dominant source of direct photons is initial hard scattering. However, in the p(T) < 4 GeV/c region dominated by thermal photons, we find a substantial direct-photon v(2) comparable to that of hadrons, whereas model calculations for thermal photons in this kinematic region underpredict the observed v(2).

Production of muons from heavy flavor decays at forward rapidity in pp and Pb-Pb collisions at sqrt[s(NN)]=2.76 TeV

The ALICE Collaboration has measured the inclusive production of muons from heavy-flavor decays at forward rapidity, 2.5<y<4, in pp and Pb-Pb collisions at sqrt[s(NN)]=2.76  TeV. The p(t)-differential inclusive cross section of muons from heavy-flavor decays in pp collisions is compared to perturbative QCD calculations. The nuclear modification factor is studied as a function of p(t) and collision centrality. A weak suppression is measured in peripheral collisions. In the most central collisions, a suppression of a factor of about 3-4 is observed in 6<p(t)<10  GeV/c. The suppression shows no significant p(t) dependence.

J/ψ suppression at forward rapidity in Pb-Pb collisions at √s(NN) = 2.76 TeV

The ALICE experiment has measured the inclusive J/ψ production in Pb-Pb collisions at √s(NN) = 2.76 TeV down to zero transverse momentum in the rapidity range 2.5 < y < 4. A suppression of the inclusive J/ψ yield in Pb-Pb is observed with respect to the one measured in pp collisions scaled by the number of binary nucleon-nucleon collisions. The nuclear modification factor, integrated over the 0%-80% most central collisions, is 0.545 ± 0.032(stat) ± 0.083(syst) and does not exhibit a significant dependence on the collision centrality. These features appear significantly different from measurements at lower collision energies. Models including J/ψ production from charm quarks in a deconfined partonic phase can describe our data.

Particle-yield modification in jetlike azimuthal dihadron correlations in Pb-Pb collisions at √s(NN)=2.76 TeV

The yield of charged particles associated with high-p(t) trigger particles (8<p(t)<15 GeV/c) is measured with the ALICE detector in Pb-Pb collisions at √s(NN)=2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jetlike correlation peaks in azimuthal dihadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta p(t)>3 GeV/c on the away side drops to about 60% of that observed in pp collisions, while on the near side a moderate enhancement of 20%-30% is found.

J/ψ polarization in pp collisions at √s=7 TeV

The ALICE Collaboration has studied J/ψ production in pp collisions at √s=7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/ψ polarization parameters λ(θ) and λ(φ) were obtained. The study was performed in the kinematic region 2.5<y<4, 2<p(t)<8 GeV/c, in the helicity and Collins-Soper reference frames. In both frames, the polarization parameters are compatible with zero, within uncertainties.

Reduction of N-tropic mutant porcine endogenous retrovirus infectivity by human tripartite motif-containing 5-isoform alpha

In cases of retroviral infection, the host cell deploys antiviral proteins as a type of innate immunity. Tripartite motif-containing 5-isoform alpha (TRIM5α) is a potent antiviral protein. TRIM5α has been reported to restrict human immunodeficiency virus (HIV) 1 infection in rhesus monkey cells by targeting the incoming viral capsid at the postentry or preintegration stage of the viral life cycle. As a consequence, virus replication and reverse transcription are interrupted. TRIM5α of human origin has also been shown to inhibit N-tropic murine leukemia virus infection. To investigate the inhibitory effect of TRIM5α on porcine endogenous retrovirus (PERV) infection in humans, we constructed a 293T cell line stably expressing human TRIM5α (293T-huTRIM5α) and tested the infectivity of vesicular stomatitis virus glycoprotein envelope pseudotyped viruses (wild-type PERV [wt-PERV], N-tropic mutant PERV, N-tropic murine leukemia virus, and MoMLV). Infectivity of N-tropic mutant PERV was reduced by 43.3% in 293T-huTRIM5α cells, a decrease in efficiency that was more than 3-fold greater than that of wt-PERV in 293T-huTRIM5α cells. Human TRIM5α exhibited inhibitory activity against N-tropic MLV and N-tropic mutant PERV, but showed no antiviral activity against Moloney murine leukemia virus or wt-PERV.

Measurements of higher order flow harmonics in Au+Au collisions at √s(NN)=200 GeV

Flow coefficients ν(n) for n=2, 3, 4, characterizing the anisotropic collective flow in Au+Au collisions at √s(NN)=200 GeV, are measured relative to event planes Ψ(n), determined at large rapidity. We report ν(n) as a function of transverse momentum and collision centrality, and study the correlations among the event planes of different order n. The ν(n) are well described by hydrodynamic models which employ a Glauber Monte Carlo initial state geometry with fluctuations, providing additional constraining power on the interplay between initial conditions and the effects of viscosity as the system evolves. This new constraint can serve to improve the precision of the extracted shear viscosity to entropy density ratio η/s.

Suppression of back-to-back hadron pairs at forward rapidity in d+Au collisions at √s(NN)=200 GeV

Back-to-back hadron pair yields in d+Au and p+p collisions at √s(NN)=200 GeV were measured with the PHENIX detector at the Relativistic Heavy Ion Collider. Rapidity separated hadron pairs were detected with the trigger hadron at pseudorapidity |η|<0.35 and the associated hadron at forward rapidity (deuteron direction, 3.0<η<3.8). Pairs were also detected with both hadrons measured at forward rapidity; in this case, the yield of back-to-back hadron pairs in d+Au collisions with small impact parameters is observed to be suppressed by a factor of 10 relative to p+p collisions. The kinematics of these pairs is expected to probe partons in the Au nucleus with a low fraction x of the nucleon momenta, where the gluon densities rise sharply. The observed suppression as a function of nuclear thickness, p(T), and η points to cold nuclear matter effects arising at high parton densities.

Cold nuclear matter effects on J/ψ yields as a function of rapidity and nuclear geometry in d+A collisions at sqrt[s(NN)]=200 GeV

We present measurements of J/ψ yields in d+Au collisions at sqrt[s(NN)]=200  GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/ψ rapidity (-2.2<y<2.4) with high statistical precision and are compared with two theoretical models: one with nuclear shadowing combined with final state breakup and one with coherent gluon saturation effects. In order to remove model dependent systematic uncertainties we also compare the data to a simple geometric model. The forward rapidity data are inconsistent with nuclear modifications that are linear or exponential in the density weighted longitudinal thickness, such as those from the final state breakup of the bound state.

Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at sqrt(s(NN)) = 2.76 TeV

We report on the first measurement of the triangular v3, quadrangular v4, and pentagonal v5 charged particle flow in Pb-Pb collisions at sqrt(s(NN)) = 2.76  TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flow v2 and v3 have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients.

Wafer Bonding Using Dielectric Polymer Thin Films in 3D Integration

A key process in our approach to monolithic three-dimensional (3D) integration is the bonding of 200-mm wafers using dielectric polymer thin films as bonding glues. After discussing the desired properties of polymer thin films, we describe how bonding protocols are evaluated using silicon and glass wafers. After bonding, the fraction of bonded area was inspected optically and a razor blade method was used to indicate bonding strength. Thermal stability and bonding integrity were evaluated using thermal cycling and backside grinding and polishing. To date, we have studied benzocyclobutene (BCB), Flare™, and methylsilsesquioxane (MSSQ) and Parylene-N as bonding glues. Wafer pairs bonded using BCB showed a larger fraction of bonded area, and those using Flare indicated higher thermal stability. Both BCB and Flare glues provided good bonding integrity after backside grinding tests. Changes in the chemical structures of BCB and Flare glue during bonding were analyzed using FTIR in order to understand the bonding mechanism and to improve the bonding process.

Evaluation of Thin Dielectric-Glue Wafer-Bonding for Three Dimensional Integrated Circuit-Applications

The critical adhesion energy of benzocyclobutene (BCB)-bonded wafers is quantitatively investigated with focus on BCB thickness, material stack and thermal cycling. The critical adhesion energy depends linearly on BCB thickness, increasing from 19 J/m2 to 31 J/m2 as the BCB thickness increases from 0.4 μm to 2.6 μm, when bonding silicon wafers coated with plasma enhanced chemical vapor deposited (PECVD) silicon dioxide (SiO2). In thermal cycling performed with 350 and 400 oC peak temperatures, the significant increase in critical adhesion energy at the interface between BCB and PECVD SiO2 during the first thermal cycle is attributed to relaxation of residual stress in the PECVD SiO2 layer. On the other hand, the critical adhesion energy at the interface between BCB and PECVD silicon nitride (SiNx) decreases due to the increase of residual stress in the PECVD SiNx layer during the first thermal cycle.

Cross section and parity-violating spin asymmetries of W± boson production in polarized p + p collisions at sqrt[s] = 500 GeV

Large parity-violating longitudinal single-spin asymmetries A(L)(e+) = -0.86(-0.14) (+0.30) and A(L)(e-) = 0.88(-0.71) (+0.12) are observed for inclusive high transverse momentum electrons and positrons in polarized p+p collisions at a center-of-mass energy of sqrt[s] = 500 GeV with the PHENIX detector at RHIC. These e± come mainly from the decay of W± and Z0 bosons, and their asymmetries directly demonstrate parity violation in the couplings of the W± to the light quarks. The observed electron and positron yields were used to estimate W± boson production cross sections for the e± channels of σ(pp → W+ X) × BR(W+ → e+ ν(e)) = 144.1 ± 21.2(stat)(-10.3) (+3.4) (syst) ± 21.6(norm)  pb, and σ(pp → W- X) × BR(W- → e- ν[over ¯](e)) = 31.7 ± 12.1(stat)(-8.2) (+10.1) (syst) ± 4.8(norm)  pb.

Dielectric GlueWafer Bonding For 3D ICs

A process to bond 200 mm wafers for wafer-level three-dimensional integrated circuit (3D-IC) applications is discussed. Four-point bending is used to quantify the bonding strength and identify the weak interface. Using benzocylcobutene (BCB) glue, the bonding strength depends on (1) glue thickness, (2) glue film preparation, and (3) materials and structures on the wafer(s). A seamless BCB-to-BCB bond interface provides the highest bonding strength compared to other interfaces in these structures (> 34 J/m2). Mechanical and electrical properties of a wafer with copper interconnect structures are preserved after wafer bonding and wafer thinning, confirming the potential of the bonding process for 3D ICs.

Bonding Characterization of Oxidized PDMS Thin Films

This paper reports on the use of poly(dimethylsiloxane) (PDMS) thin films to bond pairs of glass slides, borosilicate glass, and silicon substrates, with an emphasis on application for wafer-level three-dimensional (3D) heterogeneous integration technology platforms. PDMS films were spin-cast and cured, surface modified using low power oxygen plasma, and then bonded to various materials. These bonds were destructively tested using a four point bending technique. The critical adhesion energy obtained using surface modified PDMS to bond glass slides is 3.0 J/m2. Adhesion energies obtained using unmodified PDMS are 2.8, 1.8, and 1.6 J/m2 for bonded silicon, glass slides, and borosilicate glass, respectively. Correlation of these results to material surface and interface properties indicates that although PDMS has process advantages as a bonding material for heterogeneous integration, its adhesion strength is lower than that of other dielectric bonding glues.

Centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV

The centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV is presented. The charged-particle density normalized per participating nucleon pair increases by about a factor of 2 from peripheral (70%-80%) to central (0%-5%) collisions. The centrality dependence is found to be similar to that observed at lower collision energies. The data are compared with models based on different mechanisms for particle production in nuclear collisions.

Elliptic flow of charged particles in Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at sqrt[S(NN)] =2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η|<0.8) and transverse momentum range 0.2<p t<5.0 GeV/c. The elliptic flow signal v₂, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ± 0.002(stat) ± 0.003(syst) in the 40%-50% centrality class. The differential elliptic flow v₂ p t reaches a maximum of 0.2 near p t =3 GeV/c. Compared to RHIC Au-Au collisions at sqrt[S(NN)] 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.

Charged-particle multiplicity density at midrapidity in central Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair √ S NN = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584 ± 4(stat) ± 76(syst), which corresponds to 8.3 ± 0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at √ S NN = 2.76 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

Abstract P4-09-14: Invasive Lobular Carcinoma Is a Prototype of Luminal A Breast Cancer Subtype and Rare in Korea

Purpose Invasive lobular carcinoma (ILC) is known to be the second most frequent histologic subtype, occupying 10% of invasive breast cancer in the Western countries. The present study was designed to assess the clinical characteristics and outcomes of ILC compared to general invasive ductal carcinoma (IDC) and the luminal A subtype (LA-IDC).

Methods The study population included d 2916 patients with invasive breast cancer consecutively diagnosed at the National Cancer Center, Korea between 2001 and 2008. The clinicopathological characteristics and clinical outcomes were retrospectively reviewed.

Results There were 83 pts (2.8%) diagnosed with ILC and 1,088 pts (37.3%) with LA-IDC. Mean age was 48.2 years of all patients, 48.3 years of ILC group and 47.9 years of LA-IDC group. The ILC patients presented with a larger tumor size (≥T2, 59.8% vs. 38.8%, P=0.001), lower histologic grade (HG 1 or 2, 90.4% vs 64.4%, P&lt;0.001), more often estrogen receptor (ER) and progesterone receptor (PgR) positivity (ER+, 90.4% vs. 64.4%, P&lt;0.001; PgR+, 71.1% vs. 50.1%, P&lt;0.001), HER2 negativity (97.5% vs. 74.9%, P&lt;0.001), lower Ki-67 expression (10.3% ± 10.6% vs. 20.6% ± 19.8%, P&lt;0.001), and luminal A subtypes (91.4% vs. 51.2%, P&lt;0.001) compared to the IDC group. Six (7.2%) ILC patients and 359 (12.7%) IDC patients developed disease recurrence with a median follow-up of 56.4 months (range 4.9-136.6 months). Although ILC showed similar prognosis to IDC in general (5-year DFS rate, 91.7% in ILC vs. 87.4% in IDC, P=0.31; 5-year OS rate, 93.6% in ILC vs. 92.5% in IDC, P=0.38), its outcome was closer to LA-IDC, and better than non LA-IDC (LA-IDC (ref); ILC, HR 0.77 in recurrence, 95% CI 0.31-1.90, P=0.57; HR 0.75 in death, 95% CI 0.18-3.09, P=0.70; non LA-IDC, HR 1.69 in recurrence, 95% CI 1.23-2.33, P=0.001; HR 1.50 in death, 95% CI 0.97-2.33, P=0.07) in univariate and multivariate analysis.

Conclusions ILC is a very rare histologic subtype of breast cancer in Korea compared to the Western countries and has distinctive clinicopathological characteristics similar to those of LA-IDC. Acknowledgement: supported by NCC grant #0910320

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-09-14.

Abstract P2-09-01: Serial [18F] FDG-PET after the 2nd Cycle of Preoperative Chemotherapy Is Predictive for Pathological Complete Response in Stage II/III Breast Cancer

Purpose: One of substudies of the prospective trials aimed to evaluate the usefulness of serial [18F] 2-fluoro-2-deoxy-D-glucose-positron emission tomography ([18F] FDG-PET) for predicting pathological complete response (pCR) in stage II/III breast cancer with preoperative chemotherapy (PST).

Methods: Serial PET was undertaken in 57 breast cancer patients enrolled in three different neoadjuvant trials: 35 patients from a phase II study with paclitaxel/gemcitabine/trastuzumab with ClinicalTrial.gov NCT 00532857, 9 patients from a phase Ib study with paclitaxel/gemcitabine/lapatinib with ClinicalTrial.gov NCT 01133912, and 13 patients from a phase Ib with paclitaxel/gemcitabine/sunitinib with ClinicalTrial.gov NCT0 1070706. All patients received 6 cycles of PST followed by surgery and radiotherapy. We assessed the peak standardized uptake value (SUVp) in the primary tumor at the baseline and after the 2nd cycle (37 patients) or after completion (20 patients) of 6 cycles of PST, and calculated the reduction rate (RR) of the SUVp. Pathological response was classified into pCR and non-pCR. To compare the mean of SUVp and RR of SUVp between different response groups, two-way tables and chi-square tests were used

Results: Fifteen (40.6%) of 37 patients who took repeat PET after the 2nd PST and 15 (75%) of 20 patients after completion of PST achieved a pCR with overall pCR rate of 52.6% in the primary tumor. In patients with repeat PET after the 2nd PST, post-treatment SUVp and RR of the SUVp in primary tumors were significantly different by the pathological response (post-treatment SUVp, 1.54 ± 0.63 in pCR vs 2.54 ± 1.06 in non-pCR, P=0.002; RR of the SUVp, 79.2% ± 11.9% in pCR vs 68.9% ± 15.4% in non-pCR, P=0.03). However, in patients with repeat PET after completion of PST, there were no statistical differences of these values (post-treatment SUVp, 1.09 ± 0.63 in pCR vs 1.29 ± 0.36 in non-pCR, P=0.42; RR of the SUVp, 83.7% ± 14.0% in pCR vs 67.5% ± 21.1% in non-pCR, P=0.17)

Conclusions: This study demonstrated that repeat PET after the 2nd cycle of PST, not after completion of PST could predict pCR in stage II/III breast cancer with preoperative chemotherapy. Acknowledgement NCC Grant #0910320.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-01.

Is the Cassie-Baxter formula relevant?

The utility of the Cassie-Baxter formula to predict the apparent contact angle of a drop on rough hydrophobic surfaces has been questioned recently. To resolve this issue, experimental and numerical data for advancing and receding contact angles are reported. In all cases considered it is seen that contact angles follow the overall trend of the Cassie-Baxter formula, except for the advancing front on pillar type roughness. It is shown that deviations from the Cassie-Baxter angle have a one-to-one correlation with microscopic distortions of the contact line with respect to its configuration in the Cassie-Baxter state.

Azimuthal anisotropy of π⁰ production in Au+Au collisions at sqrt((s)NN)=200 GeV: path-length dependence of jet quenching and the role of initial geometry

We have measured the azimuthal anisotropy of π⁰ production for 1<p(T)<18  GeV/c for Au+Au collisions at sqrt((s)NN)=200  GeV. The observed anisotropy shows a gradual decrease for 3≲p(T)≲7-10  GeV/c, but remains positive beyond 10  GeV/c. The magnitude of this anisotropy is underpredicted, up to at least ∼10  GeV/c, by current perturbative QCD (PQCD) energy-loss model calculations. An estimate of the increase in anisotropy expected from initial-geometry modification due to gluon saturation effects and fluctuations is insufficient to account for this discrepancy. Calculations that implement a path-length dependence steeper than what is implied by current PQCD energy-loss models show reasonable agreement with the data.

Midrapidity antiproton-to-proton ratio in pp collisons at sqrt[s]=0.9 and 7 TeV measured by the ALICE experiment

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at sqrt[s]=0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45<p_{t}<1.05  GeV/c and rapidity |y|<0.5. The ratio is measured to be R_{|y|<0.5}=0.957±0.006(stat)±0.014(syst) at 0.9 TeV and R_{|y|<0.5}=0.991±0.005(stat)±0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.

Elliptic and hexadecapole flow of charged hadrons in Au+Au collisions at sq.rt(s(NN))=200 GeV

Differential measurements of the elliptic (v(2)) and hexadecapole (v(4)) Fourier flow coefficients are reported for charged hadrons as a function of transverse momentum (p(T)) and collision centrality or number of participant nucleons (N(part)) for Au+Au collisions at sq.rt(s(NN))=200  GeV. The v(2,4) measurements at pseudorapidity |η|≤0.35, obtained with four separate reaction-plane detectors positioned in the range 1.0<|η|<3.9, show good agreement, indicating the absence of significant Δη-dependent nonflow correlations. Sizable values for v(4)(p(T)) are observed with a ratio v(4)(p(T),N(part))/v(2)(2)(p(T),N(part))≈0.8 for 50≲N(part)≲200, which is compatible with the combined effects of a finite viscosity and initial eccentricity fluctuations. For N(part)≳200 this ratio increases up to 1.7 in the most central collisions.

Transition in yield and azimuthal shape modification in dihadron correlations in relativistic heavy ion collisions

Hard-scattered parton probes produced in collisions of large nuclei indicate large partonic energy loss, possibly with collective produced-medium response to the lost energy. We present measurements of π^{0} trigger particles at transverse momenta p{T}{t}=4-12  GeV/c and associated charged hadrons (p{T}{a}=0.5-7  GeV/c) vs relative azimuthal angle Δϕ in Au+Au and p+p collisions at sqrt[s{NN}]=200  GeV. The Au+Au distribution at low p{T}{a}, whose shape has been interpreted as a medium effect, is modified for p{T}{t}<7  GeV/c. At higher p{T}{t}, the data are consistent with unmodified or very weakly modified shapes, even for the lowest measured p{T}{a}, which quantitatively challenges some medium response models. The associated yield of hadrons opposing the trigger particle in Au+Au relative to p+p (I{AA}) is suppressed at high p{T} (I{AA}≈0.35-0.5), but less than for inclusive suppression (R{AA}≈0.2).

Enhanced production of direct photons in Au + Au collisions at square root(S(NN)) = 200 GeV and implications for the initial temperature

The production of e+ e- pairs for m(e+ e-)<0.3 GeV/c2 and 1<p(T)<5 GeV/c is measured in p+p and Au+Au collisions at square root(S(NN))=200 GeV. An enhanced yield above hadronic sources is observed. Treating the excess as photon internal conversions, the invariant yield of direct photons is deduced. In central Au+Au collisions, the excess of the direct photon yield over p+p is exponential in transverse momentum, with an inverse slope T=221+/-19(stat)+/-19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T(init) approximately 300-600 MeV at times of approximately 0.6-0.15 fm/c after the collision are in qualitative agreement with the data. Lattice QCD predicts a phase transition to quark gluon plasma at approximately 170 MeV.

Prognostic Factors for Locoregional Recurrence in Operable Breast Cancer Patients Treated with Preoperative Systemic Chemotherapy

Background: We aimed to evaluate the clinicopathologic factors affecting locoregional recurrence (LRR) in potentially operable breast cancer patients receiving preoperative systemic chemotherapy (PST).Methods: We reviewed the records of 316 breast cancer patients treated with PST (doxorubicin/cyclophosphamide, 101; docetaxel /capecitabine, 103; paclitaxel/gemcitabine, 43; doxorubicin/docetaxel, 69) followed by surgery and adjuvant radiotherapy between 2002 and 2006. The majority of patients had clinical positive axillary lymph nodes. To define the prognostic factors for LRR, age, clinical stage, hormone receptor (HR) and HER2 status, clinical and pathologic response, type of operation, pathological characteristics including tumor size, tumor grade, nodal status, number of positive axillary nodes, size of metastatic lymph node and status of resection margin and tumor multiplicity before and after PST were analyzed.Results: Overall 52 patients (16.5%) in the primary tumor and 87 patients (27.5%) in the axillary nodes achieved a pathologic complete response (pCR), and 206 patients (65.2%) underwent breast conserving surgery (BCS). With a median follow-up of 52.4 month (range: 4.7 - 89.4), total 18 (5.7%) patients developed LRR; 2 of 110 (1.8%) patients with mastectomy vs. 16 of 206 (7.7%) patients with BCS (p=0.04). Other significant factors in the univariate analysis were clinical T stage, HR status, clinical response and tumor multiplicity. A pCR in the primary tumor or node was not a prognostic factor for LRR in this study. In multivariate analysis, clinical T stage (T3/4, HR 7.8; 95% CI, 2.33-26.24; P=0.001), hormone receptor status (negative, HR 6.2; 95% CI, 1.91-20.22; P=0.002) and type of surgery (BCS, HR 9.5; 95% CI, 1.97-46.37; P=0.005) were independent prognostic factors. Among patients with BCS, advanced clinical T stage (HR 12.4; 95% CI, 3.45-44.56; P&lt;0.001), negative hormone receptor (HR 4.74; 95% CI, 1.33-16.96; P=0.02), non-responding disease (HR 6.54; 95% CI, 1.07-40.12; P=0.04) and multiple tumors (HR 4.36; 95% CI, 1.06-17.90; P=0.04) developed more frequent LRR.Conclusions: Significantly more patients with advanced clinical T stage, negative HR status and BCS developed LRR in operable breast cancer treated with PST. Moreover, in patients with BCS after PST, clinically non-responding disease and multiple tumors showed unfavorable prognosis besides the larger tumors and negative hormone receptor.Partly supported by NCC Grant No 0610240

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1095.

New HER2 Assay Using Trastuzumab for the Selection of Trastuzumab Responding Breast Cancer: The Positivity Is Significantly Associated with Pathologic Complete Response after Preoperative Chemotherapy

Background:The evaluation of HER2 status is required for trastuzumab therapy in breast cancer. Although there are a few methods for an evaluation of HER2 status, theoretically the better method would be to check trastuzumab uptake itself in the tumor after trastuzumab administration. Therefore, we developed a different HER2 test (QHerceptest) using trastuzumab to improve an accuracy in the selection of patient for trastuzumab therapy.Patients and Methods:31 patients with HER2 positive (IHC 3+: 19 and IHC 2+ with FISH positive: 12) early breast cancer who were enrolled in a phase II preoperative paclitaxel, gemcitabin and trastuzumab (PGH) combination chemotherapy trial were evaluated. The pre-chemotherapy tumor specimens were obtained from the breast mass (n=24) or metastatic lymph nodes (n=7). After completing 6 cycles of PGH therapy, all patients underwent breast conserving surgery or mastectomy. We applied trastuzumab and Quantum dot conjugated goat anti-human IgG (QD-IgG, 655nm, Invitrogen) in the process of immunuhistochemistry for HER2 using formalin-fixed paraffin embedded specimen. After antigen retrieval, trastuzuamb was applied followed by QD-IgG. The result of QHerceptest was scored as negative, weak positive, moderate positive, or strong positive, and its relative uptake (RU) were quantified by imaging analysis program (Q-IHC, http://www.bio-miblab.org).Results:The uptake of trastuzumab by QHerceptest was heterogenous, varying between 1.3% to 193.7%. Twenty one of 31 (67.7%) patients achieved pathologic complete response (pCR): 11 of 12 patients (91.7%) with QHerceptest strong positive tumors, 6 of 9 patients (66.7%) with QHerceptest moderate positive tumors, and 4 of 7 patients (57.1%) with QHerceptest weak positive tumors, and none of 3 patients (9.4%) with QHerceptest negative tumors (p=0.0203). Besides, RU was significantly different between non-pCR and pCR groups (43.9±38.3, 80.8±47.1, p=0.0396)Conclusion:We developed a new HER2 assay using trastuzumab and applied to clinical specimen. This assay showed heterogenous trastuzumab uptake in this patient population. Although the data need to be verified by further study, the assay could possibly eliminate patients among HER2 positive breast cancer who will not get benefit by trastuzumab .This study was supported by NCC Grant No 0710292-2 and NCC Grant No 0610240.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6050.