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.

Halo structure of the island of inversion nucleus 31Ne

The cross sections for single-neutron removal from the very neutron-rich nucleus 31Ne on Pb and C targets have been measured at 230 MeV/nucleon using the RIBF facility at RIKEN. The deduced large Coulomb breakup cross section of 540(70) mb is indicative of a soft E1 excitation. Comparison with direct-breakup model calculations suggests that the valence neutron of 31Ne occupies a low-l orbital (most probably 2p(3/2)) with a small separation energy (S(n) approximately < 0.8 MeV), instead of being predominantly in the 1f(7/2) orbital as expected from the conventional shell ordering. These findings suggest that 31Ne is the heaviest halo system known.

A Retrospective Analysis of Risk Factors of Central Nervous System Metastases in Operable Breast Cancer: Different Survival by Biological Subtype and Ki67 Overexpression

Background: New agents have improved systemic disease control, but the control of central nervous system (CNS) metastases is still insufficient. The identification of factors that may predispose to CNS metastases may help lead to earlier detection possibly to improvement in disease management.Methods: Patients (pts) with metastatic who were diagnosed with clinical stage I-III primary breast cancer at National Cancer Center Hospital East from January 2003 to December 2005 were screened. All pts with CNS metastases were identified by CT or MRI. Cox proportional hazards models were fitted to find risk factors of CNS metastases. Factors included age, menopausal status, clinical stage, T stage, histological grade, lymphovascular invasion, hormone and HER2 status, and Ki67 (at least 30% tumor cells positive). Survival was calculated by the Kaplan-Meier method.Results: Median follow-up from operation was 53.5 months. Of 591 breast cancer pts, 76 pts (12.9%) relapsed. Seventeen pts (2.9%) developed CNS metastases; 5 pts developed as the first recurrence site. Multivariable analysis indicated the higher risk for developing CNS metastases were triple negative (TN) tumors (HR 5.532, 95% CI 1.445-21.180, p=0.013) and Ki67 overexpression (HR 3.906, 95% CI 1.179-12.939, p=0.026). There were no statistically significant differences in other factors. CNS metastasesCumulative incidence of CNS metastases (4 yrs)Median duration to CNS metastases (Months)Overall survival (4 yrs)Disease free survival (4 yrs)TN9.7% (9/93 pts)9.4%11.378.5%73.3%HER2 positive3.7% (4/107 pts)4.4%20.391.0%84.9%Others1.0% (4/391 pts)0.8% (p&lt;0.0001)24.197.5% (p&lt;0.0001)92.4% (p&lt;0.0001)      Ki67 ≥30%8.6% (12/140 pts)9.4%12.382.4%75.0%Ki67 &lt;30%1.1% (5/446 pts)0.7% (p&lt;0.0001)23.996.7% (p&lt;0.0001)92.0% (p&lt;0.0001) Discussion: In our analysis, TN or Ki67 overexpression breast cancer showed earlier CNS metastases and shorter overall survival. In case of these tumors, there is higher probability for early detection of limited CNS metastatic involvement.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6053.

Charged Kaon interferometric probes of space-time evolution in Au+Au collisions at sqrt[S(NN)]=200 GeV

Bose-Einstein correlations of charged kaons are used to probe Au+Au collisions at sqrt[S(NN)]=200 GeV and are compared to charged pion probes, which have a larger hadronic scattering cross section. Three-dimensional Gaussian source radii are extracted, along with a one-dimensional kaon emission source function. The centrality dependences of the three Gaussian radii are well described by a single linear function of N(part)1/3 with a zero intercept. Imaging analysis shows a deviation from a Gaussian tail at r greater than or approximately equal to 10 fm, although the bulk emission at lower radius is well described by a Gaussian. The presence of a non-Gaussian tail in the kaon source reaffirms that the particle emission region in a heavy-ion collision is extended, and that similar measurements with pions are not solely due to the decay of long-lived resonances.

Measurement of bottom versus charm as a function of transverse momentum with electron-hadron correlations in p + p collisions at square root of s = 200 GeV

The momentum distribution of electrons from semileptonic decays of charm and bottom quarks for midrapidity |y|<0.35 in p+p collisions at square root of s=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range 2<pT<7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D-->e(+/-)K(-/+)X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in pT. A fixed-order-plus-next-to-leading-log perturbative quantum chromodynamics calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is sigma(bb)=3.2(-1.1)(+1.2)(stat)(-1.3)(+1.4)(syst)mub.

Gluon-spin contribution to the proton spin from the double-helicity asymmetry in inclusive pi0 production in polarized p+p collisions at [sqrt]s=200 GeV

The double helicity asymmetry in neutral pion production for pT=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DeltaG, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of micro2=4 GeV2 a next to leading order QCD analysis gives DeltaG[0.02,0.3]=0.2, with a constraint of -0.7<DeltaG[0.02,0.3]<0.5 at Deltachi2=9 (approximately 3sigma) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the DeltaG constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.

Long-term prognosis of late spontaneous reperfusion after failed thrombolysis for acute myocardial infarction

BACKGROUND

Early reperfusion improves left ventricular (LV) function and survival after acute myocardial infarction (MI). Thrombolytic therapy achieves early patency of the infarct artery in about two-thirds of patients. In nearly half of the remaining patients, in whom early reperfusion was not achieved with thrombolytic therapy, the infarct artery might reopen by the time of predischarge angiography. However, the impact of such late spontaneous reperfusion after failed thrombolytic therapy on LV function and long-term survival remained unclear.

HYPOTHESIS

This study was undertaken to assess implication of late spontaneous reperfusion after failed thrombolytic therapy on LV function and long-term survival after acute MI.

METHODS

The study consisted of 198 patients with anterior acute MI who underwent thrombolytic therapy and predischarge angiography: 160 patients with infarct artery patent early and late after therapy (persistent patency), 17 patients with infarct artery occluded early after therapy but patent at predischarge angiography (late spontaneous reperfusion), and 21 patients with infarct artery occluded early and late after therapy (persistent occlusion).

RESULTS

Persistent patency was associated with enhanced improvement in LV ejection fraction (7.7 +/- 11.8%) compared with late spontaneous reperfusion (0.0 +/- 9.6%, p = 0.03) and persistent occlusion (-1.4 +/- 9.7%, p = 0.003). Persistent patency was associated with better long-term survival than with late spontaneous reperfusion (p < 0.001) and persistent occlusion (p < 0.001). Multivariate analysis comparing persistent patency and late spontaneous reperfusion showed that early reperfusion was an independent predictor of long-term survival.

CONCLUSION

Late spontaneous reperfusion after failed thrombolytic therapy was associated with poor LV function and long-term survival, emphasizing the importance of early reperfusion.

Development of large deformation in 62Cr

The structure of neutron-rich isotopes 60Cr and 62Cr was studied via proton inelastic scattering in inverse kinematics. The deformation lengths (delta) for 60Cr and 62Cr were extracted as 1.12(16) and 1.36(14) fm, respectively, providing evidence for enhanced collectivity in these nuclei. An excited state at 1180(10) keV in 62Cr was identified for the first time. We adopted 4;{+} as its spin and parity, leading to the rapid increase of the Ex(4;{+})/E_{x}(2;{+}) ratio, which indicates the development of large deformation in 62Cr near N=40. Importance of the admixture of the gd-shell component above N=40 is also discussed by comparing with a modern shell model calculation.

Experimental evaluation of photocrosslinkable chitosan hydrogel as injection solution for endoscopic resection

BACKGROUND AND STUDY AIMS

Saline as an injection solution for endoscopic resection techniques has several disadvantages such as a short-lasting effect leading to a potentially higher risk of bleeding and perforation. The new substance of photocrosslinkable chitosan hydrogel in a DMEM/F12 medium (PCH) can be converted into an insoluble hydrogel by ultraviolet irradiation for 30 s, and was evaluated in two sets of animal experiments.

METHODS

18 pigs were used in the two parts of the study. First, mucosal resections were done with either PCH or hypertonic saline; the effects of both agents on wound healing were examined endoscopically and histologically. Second, in vivo degradation of PCH was examined using six pig stomachs.

RESULT

PCH injection led to a longer-lasting elevation with clearer margins, compared with hypertonic saline, thus enabling precise endoscopic submucosal dissection (ESD) along the margins of the elevated mucosa. The endoscopic appearance after ESD was similar in both groups. PCH biodegradation was completed within 8 weeks according to endoscopic and histologic analyses.

CONCLUSION

PCH is a promising agent for submucosal injection prior to various techniques of endoresection. It should be evaluated in clinical trials after biocompatibility testing for PCH is completed.

Suppression pattern of neutral pions at high transverse momentum in Au + Au collisions at sqrt[sNN]=200 GeV and constraints on medium transport coefficients

For Au + Au collisions at 200 GeV, we measure neutral pion production with good statistics for transverse momentum, pT, up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5 < pT < 20 GeV/c. Experimental uncertainties are small enough to constrain any model-dependent parametrization for the transport coefficient of the medium, e.g., q in the parton quenching model. The spectral shape is similar for all collision classes, and the suppression does not saturate in Au + Au collisions.

Onset of pi(0) suppression studied in Cu+Cu collisions at sqrt S NN=22.4, 62.4, and 200 GeV

Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or approximately 0.35) were measured in Cu+Cu collisions at sqrt[s(NN)]=22.4, 62.4, and 200 GeV. Relative to pi_(0) yields in p+p collisions scaled by the number of inelastic nucleon-nucleon collisions (N(coll) the pi_(0) yields for p(T) more than or approximately 2 GeV/c in central Cu+Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu+Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone.

J/psi production in sqrt s_NN=200 GeV Cu+Cu collisions

Yields for J/psi production in Cu+Cu collisions at sqrt s_NN=200 GeV have been measured over the rapidity range |y|<2.2 and compared with results in p+p and Au+Au collisions at the same energy. The Cu+Cu data offer greatly improved precision over existing Au+Au data for J/psi production in collisions with small to intermediate numbers of participants, in the range where the quark-gluon plasma transition threshold is predicted to lie. Cold nuclear matter estimates based on ad hoc fits to d+Au data describe the Cu+Cu data up to N_part approximately 50, corresponding to a Bjorken energy density of at least 1.5 GeV/fm(3).

Particle-species dependent modification of jet-induced correlations in Au+Au collisions at sqrt[s_{NN}]=200 GeV

Measurements in Au+Au collisions at sqrt[s_{NN}]=200 GeV of jet correlations for a trigger hadron at intermediate transverse momentum (p_{T,trig}) with associated mesons or baryons at lower p_{T,assoc} indicate strong modification of the away-side jet. The ratio of jet-associated baryons to mesons increases with centrality and p_{T,assoc}. For the most central collisions, the ratio is similar to that for inclusive measurements. This trend is incompatible with in-vacuum fragmentation but could be due to jetlike contributions from correlated soft partons, which recombine upon hadronization.

Source breakup dynamics in Au + Au collisions at sqrt[s(NN)]=200 GeV via three-dimensional two-pion source imaging

A three-dimensional correlation function obtained from midrapidity, low p(T), pion pairs in central Au+Au collisions at sqrt[s(NN)]=200 GeV is studied. The extracted model-independent source function indicates a long range tail in the directions of the pion pair transverse momentum (out) and the beam (long). A proper breakup time tau(0) ~ 9 fm/c and a mean proper emission duration Delta tau ~ 2 fm/c, leading to sizable emission time differences ({|Delta t(LCM)|} approximately 12 fm/c), are required to allow models to be successfully matched to these tails. The model comparisons also suggest an outside-in "burning" of the emission source reminiscent of many hydrodynamical models.

Mutation screening of the CARD15 gene in sarcoidosis

CARD15 was first identified as a susceptibility gene for Crohn's disease. More recently, CARD15 mutations were shown to be associated with the pediatric granulomatous inflammatory diseases, Blau syndrome and early-onset sarcoidosis (EOS). The aim of the present study was to evaluate whether CARD15 variants also play a role in patients with ordinary sarcoidosis other than EOS. We enrolled 135 Japanese sarcoidosis patients with uveitis as well as 95 healthy individuals and performed mutation analysis by direct sequencing of CARD15 exon 4. Direct DNA sequencing in the sarcoidosis patients showed eight CARD15 variants, including five novel mutations (13402C>T, 13543C>T, 13775C>A, 13937G>A, and 14079C>T). Compared with healthy individuals, CARD15 mutations are not common in the Japanese patients with sarcoidosis. Based on the results, we examined the clinical manifestations in patients with sarcoidosis according to their CARD15 mutations. Sarcoidosis patients with these mutations have no specific clinical features with regard to course of the disease or disease severity. Our results indicate that in general, CARD15 mutations may not contribute to the risk of sarcoidosis.

Elliptic flow for phi mesons and (anti)deuterons in Au+Au collisions at square root of sNN=200 GeV

Differential elliptic flow (v(2)) for phi mesons and (anti)deuterons (d)d is measured for Au+Au collisions at square root of sNN=200 GeV. The v(2) for phi mesons follows the trend of lighter pi+/- and K+/- mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v(2) values for (d)d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v(2) per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics.

System size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at square root sNN=200 and 62.4 GeV

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.

J/psi production versus transverse momentum and rapidity in p+p collisions at square root s=200 GeV

J/psi production in p+p collisions at square root s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over a rapidity range of -2.2<y<2.2 and a transverse momentum range of 0<pT<9 GeV/c. The size of the present data set allows a detailed measurement of both the pT and the rapidity distributions and is sufficient to constrain production models. The total cross section times the branching ratio is Bll sigma pp J/psi=178+/-3stat+/-53sys+/-18norm nb.

J/psi production versus centrality, transverse momentum, and rapidity in Au+Au collisions at square root sNN=200 GeV

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2<y<2.2 in Au+Au collisions at square root sNN=200 GeV. The J/psi invariant yield and nuclear modification factor RAA as a function of centrality, transverse momentum, and rapidity are reported. A suppression of J/psi relative to binary collision scaling of proton-proton reaction yields is observed. Models which describe the lower energy J/psi data at the CERN Super Proton Synchrotron invoking only J/psi destruction based on the local medium density predict a significantly larger suppression at RHIC and more suppression at midrapidity than at forward rapidity. Both trends are contradicted by our data.

Cultured articular chondrocytes sheets for partial thickness cartilage defects utilizing temperature-responsive culture dishes

The extracellular matrix (ECM) of articular cartilage has several functions that are unique to joints. Although a technique for transplanting cultured chondrocytes has already been introduced, it is difficult to collect intact ECM when using enzymes to harvest samples. Temperature-responsive culture dishes have already been clinically applied in the fields of myocardial and corneal transplantation. Earlier studies have shown that a sheet of cultured cells with intact ECM and adhesive factors can be harvested using such culture dishes, which allow the surface properties of the dish to be reversibly altered by changing the temperature. Human chondrocytes were subjected to enzymatic digestion and then were seeded in temperature-responsive culture dishes. A sheet of chondrocytes was harvested by only reducing the temperature after the cultured cells reached confluency. A real-time PCR analysis of the chondrocyte sheets confirmed that type II collagen, aggrecan, and fibronectin were present. These results suggested that, although chondrocytes undergo dedifferentiation in a monolayer culture, multilayer chondrocyte sheets grown in a similar environment to that of three-dimensional culture may be able to maintain a normal phenotype. A histological examination suggested that multilayer chondrocyte sheets could thus prevent the loss of proteoglycans because the area covered by the sheets was well stained by safranin-O. The present experiments suggested that temperature-responsive culture dishes are useful for obtaining cultured chondrocytes, which may then be clinically employed as a substitute for periosteal patches because such sheets can be applied without a scaffold.

Submucosal injection, for endoscopic mucosal resection, of photocrosslinkable chitosan hydrogel in DMEM/F12 medium

BACKGROUND AND STUDY AIMS

We studied the ability of a photocrosslinkable chitosan in DMEM/F12 medium to maintain submucosal thickness and to reduce bleeding after mucosal resection. We also investigated the behavior of chitosan hydrogels with regard to wound healing.

METHODS

The gastric submucosal layer of heparinized rats was injected with the photocrosslinkable chitosan in medium (which was then irradiated with ultraviolet light to form a hydrogel), or with sodium hyaluronate, or hypertonic saline, and three investigations were done, using three different sets of rats. The first and second were measurement of the thickness of the layer, and of the amount of bleeding induced by mucosal resection, respectively. Thirdly, the effects of the chitosan hydrogel on wound healing were examined histologically.

RESULTS

Gastric submucosal layers of chitosan hydrogel-treated animals remained significantly thicker than those of other groups for at least 6 h after injection. The total amount of bleeding 20 min after mechanical mucosal resection was 170.0 +/- 20.0 mg, 678.3 +/- 226.3 mg, and 1020.0 +/- 104.1 mg in the chitosan hydrogel, sodium hyaluronate, and hypertonic saline groups, respectively. Histological study revealed that the focus of bleeding was surrounded by chitosan hydrogel and that almost all the hydrogel was biodegraded within 4 weeks. Furthermore, a discernible, but not statistically significant effect of the chitosan hydrogel on wound healing was observed.

CONCLUSIONS

The chitosan hydrogel produced mucosal elevation after submucosal injection with ultraviolet irradiation, and it significantly reduced bleeding after mucosal resection. Our newly developed chitosan hydrogel in medium might be a promising submucosal agent for endoscopic mucosal resection.