T. A. Armstrong, K. N. Barish, S. Batsouli, S. J. Bennett, M. Bertaina, A. Chikanian, S. D. Coe, T. M. Cormier, R. Davies, C. B. Dover, P. Fachini, B. Fadem, L. E. Finch, N. K. George, S. V. Greene, P. Haridas, J. C. Hill, A. S. Hirsch, R. Hoversten, H. Z. Huang, H. Jaradat, B. S. Kumar, T. Lainis, J. G. Lajoie, R. A. Lewis, Q. Li, B. Libby, R. D. Majka, T. E. Miller, M. G. Munhoz, J. L. Nagle, I. A. Pless, J. K. Pope, N. T. Porile, C. A. Pruneau, M. S. Z. Rabin, J. D. Reid, A. Rimai, A. Rose, F. S. Rotondo, J. Sandweiss, R. P. Scharenberg, A. J. Slaughter, G. A. Smith, X. M. L. Tincknell, W. S. Toothacker, G. Van Buren, F. K. Wohn, and Z. Xu

Using an in vivo arterio-venous loop-containing tissue-engineering chamber, we have created a variety of vascularized tissue blocks, including functional myocardium. The viability of the transplanted cells is limited by the rate of neovascularization in the chamber. A Nox2-containing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is thought to have a critical role in ischaemic angiogenesis. In this study we investigated whether NADPH oxidase is involved in the neovascularization process in the tissue-engineering chamber. New blood vessels originating from the venous and the arterial ends of the loop could be identified after 3 days, and the vessel density (by lectin staining) peaked after 7 days and was maintained for at least 14 days. This was accompanied by granulation tissue formation and concomitant increase in the mRNA level of Nox4 NADPH oxidase. Although the total level of Nox2 mRNA in the chamber tissue decreased from day 3 to day 7, immunohistochemistry identified a strong expression of Nox2 in the endothelial cells of the new vessels. In human microvascular endothelial cells, the NADPH oxidase inhibitor apocynin reduced NADPH oxidase activity and inhibited the angiogenic responses in vitro. Local treatment with the NADPH oxidase inhibitors apocynin or gp91ds-tat peptide significantly suppressed the vessel growth in the chamber. In conclusion, NADPH oxidase-dependent redox signalling is important for neovascularization in this novel tissue-engineering chamber in vivo, and boosting this signalling might be a new approach to extending vascularization and tissue growth.

We present measurements from BNL AGS Experiment E864 of the $^{3}_{\Lambda}H$ invariant multiplicity and of the 90% Confidence Level upper limit on the $^{4}_{\Lambda}H$ yield in central 11.5 A GeV/c Au + Pt collisions. The measurements span a rapidity range from center of mass, $y_{cm}$, to $y_{cm}$+1 and a transverse momentum range of $0.<p_{T}\le 1.5$ GeV/c. We compare these results with E864 measurements of stable light nuclei and particle unstable nuclei yields of the same baryon number. The implications of these results for the coalescence of strange clusters are discussed.

We present measurements from BNL AGS Experiment 864 of the $_{\\ensuremath{\\Lambda}}^{3}\\mathrm{H}$ yield and of an upper limit on the $_{\\ensuremath{\\Lambda}}^{4}\\mathrm{H}$ yield in central $11.5A\\phantom{\\rule{0.3em}{0ex}}\\text{GeV}∕c\\phantom{\\rule{0.3em}{0ex}}\\text{Au}+\\text{Pt}$ collisions. The measurements span a rapidity range from center of mass, ${y}_{\\mathrm{c.m.}}$, to ${y}_{\\mathrm{c.m.}}+1$ and a transverse momentum range of $0l{p}_{t}\\ensuremath{\\leqslant}1.5\\phantom{\\rule{0.3em}{0ex}}\\text{GeV}∕c$. We compare these results with E864 measurements of stable light nuclei and particle unstable nuclei yields of the same baryon number. The implications of these results for the coalescence of strange clusters are discussed.

We report measurements from experiment E864 at the BNL-AGS of the yields of particle unstable light nuclei in central collisions of Au-197 with beam momentum of 11.5A GeV/c on Pt-197. Yields are reported as a function of rapidity for the nuclei H-4, Li-4, He-5, and Li-5 in the rapidity range from y(c.m.) to y(c.m.)+0.8 and in the transverse momentum range of approximately 0.1 less than or equal to p(T)/A less than or equal to 0.4 GeV/c. The yields are compared to previously reported yields and trends for the production of stable light nuclei. The nonobservation of two excited states He-5(16.75 MeV)* and Li-5(16.66 MeV)* is used to set an upper limit on the yields of these states.

We present the final results from Experiment 864 of a search for charged and neutral strange quark matter produced in interactions of 11.5 GeV/c per nucleon Au beams with Pt or Pb targets. Searches were made for strange quark matter with A>4. Approximately 30 billion 10% most central collisions were sampled and no strangelet states with A<100 were observed. We find 90% confidence level upper limits of approximately 10^{-8} per central collision for both charged and neutral strangelets. These limits are for strangelets with proper lifetimes greater than 50 ns. Also limits for H^{0}-d and pineut production are given. The above limits are compared with the predictions of various models. The yields of light nuclei from coalescence are measured and a penalty factor for the addition of one nucleon to the coalescing nucleus is determined. This is useful in gauging the significance of our upper limits and also in planning future searches for strange quark matter.

We report on measurements by the E864 experiment at the BNL-AGS of the yields of light nuclei in collisions of Au(197) with beam momentum of 11.5 A GeV/c on targets of Pb(208) and Pt(197). The yields are reported for nuclei with baryon number A=1 up to A=7, and typically cover a rapidity range from y(cm) to y(cm)+1 and a transverse momentum range of approximately 0.1 < p(T)/A < 0.5 GeV/c. We calculate coalescence scale factors B(A) from which we extract model dependent source dimensions and collective flow velocities. We also examine the dependences of the yields on baryon number, spin, and isospin of the produced nuclei.

We present results of a search for neutral strange quark matter (strangelets) in 11.6A GeV/c Aut-Pb reactions from the 1995 run of experiment E864 at the Brookhaven Alternating Gradient Synchrotron. We have sampled approximately 1.3 billion 10% most central Au+Pb interactions and have observed no statistically significant signal for neutral strangelet states with baryon number in the range 620 GeV/c(2) These limits are the first limits reported on the production of heavy neutral strangelets. They complement searches for positively and negatively charged strangelets also conducted by our collaboration. We discuss the implications of these results on strangelet production mechanisms and the stability of strange quark matter. [S0556-2813(99)50504-9].

We present results from Experiment 864 for antiproton production and antideuteron limits in Au + Pb collisions at 11.5 GeV/c per nucleon. We have measured invariant multiplicities for antiprotons for rapidities 1.4

Light nuclei can be produced in the central reaction zone via coalescence in relativistic heavy ion collisions. E864 at BNL has measured the production of ten light nuclei with nuclear number of A=1 to A=7 at rapidity $y\simeq1.9$ and $p_{T}/A\leq300MeV/c$. Data were taken with a Au beam of momentum of 11.5 A $GeV/c$ on a Pb or Pt target with different experimental settings. The invariant yields show a striking exponential dependence on nuclear number with a penalty factor of about 50 per additional nucleon. Detailed analysis reveals that the production may depend on the spin factor of the nucleus and the nuclear binding energy as well.

Experiment E864 at the Brookhaven AGS accelerator uses a high sensitivity, large acceptance spectrometer, designed to search for strangelets and other novel forms of matter produced in high-energy heavy ion collisions. The spectrometer has excellent acceptance and rate capabilities for measuring the production properties of known particles and nuclei such as p̄, d̄ and 6He. The experiment uses a magnetic spectrometer and employs redundant time of flight and position detectors and a hadronic calorimeter. In this paper we describe the design and performance of the spectrometer.

We present measurements from Brookhaven AGS Experiment 864 of neutron invariant multiplicity in 11.5A GeV/c Au+Pb collisions. The measurements span a rapidity range from center of mass to beam rapidity (y(beam) = 3.2) and are presented as a function of event centrality. The results are compared with E864 measurements of proton invariant multiplicity and an average n/p ratio at hadronic freeze-out of 1.19 +/- .08 is determined for the rapidity range y = 1.6 to y = 2.4. We discuss briefly the implications of this ratio within a simple equilibrium model of the collision system. [S0556-2813(99)02112-3].

A large hadronic lead scintillating fiber calorimeter has been built and integrated into the AGS experiment E864 [C. Pruneau et al., E864 Collaboration, Proc. 6th Internal. Conf. on Calorimetry in High Energy Physics, 1996, Frascati, Italy; F. Rotondo et al., E864 Collaboration, Proc. Quark Matter'96, Heidelberg, Germany, 20 May 1996] spectrometer to provide an independent measurement of the mass of particles produced in heavy ion collisions. The "spaghetti-type" calorimeter design and construction techniques are described in detail. Results from a prototype and the full implementation of the calorimeter are reported. The hadronic energy resolution of the calorimeter is found to be 6E/E = 0.035(± 0.005) + 0.344(± 0.008)/trE/GeV, in very good agreement with a FLUKA calculation. The hadronic time resolution is measured to be better than 400 ps. The combined calorimeter energy and time signals provide for a mass determination with good resolution. The mass resolution scales as δm/m = 0.026 + 0.347/√E(GeV) for velocities v/c < 0.98.

We have measured the yields of protons and A=2-4 nuclei in collisions between 10.8 A GeV/ c Au beams and targets of Al, Cu, and Au. The data, which cover a broad rapidity range at low transverse momenta, were measured as a function of collision centrality using a focusing beam line spectrometer and a high-rate centrality detector. We investigate the dependence of coalescence parameters on event geometry. The data are compared with the predictions of an RQMD+coalescence model. {copyright} {ital 1998} {ital The American Physical Society}

Experiment E878 at the BNL-AGS has measured the invariant cross sections of antiprotons produced near p(t)=0 in interactions of 10.8 GeV/c Au beams with targets of Al, Cu, and Au. The data were measured for a wide range of centralities and rapidities using a focusing beamline spectrometer and a high-rate centrality detector. We compare our data with the predictions of simple models and sophisticated transport models to explore the physics of antiproton production and annihilation.

We report on a search for metastable positively and negatively charged states of strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864. We have sampled approximately six billion 10% most central Au+Pb interactions and have observed no strangelet states (baryon number A < 100 droplets of strange quark matter). We thus set upper limits on the production of these exotic states at the level of 1-6 x 10^{-8} per central collision. These limits are the best and most model independent for this colliding system. We discuss the implications of our results on strangelet production mechanisms, and also on the stability question of strange quark matter.

The production of pions, protons and deuterons is studied at a laboratory angle of 144° in 28Si+Pb collisions at 14.6 GeV/c per nucleon. The centrality dependence of the pion yields is studied over the full impact parameter range using a zero degree calorimeter. The results are compared with the hadronic cascade model RQMD. These calculations are generally in agreement with the experimental results. According to these calculations, the pion yield in our acceptance is completely dominated by Δ-decay at freeze-out. Our measurements thus support the importance of baryon resonance production as one of the central features of relativistic heavy ion collisions at AGS energies. Although the strength of the pion spectrum is adequately described for kinetic energies above 50 MeV, an additional very soft component is observed in the pion spectra which is not predicted by RQMD. This very soft component accounts for a significant fraction of the total pion yield in this rapidity range but remains unexplained.

We present the first results from the E864 collaboration on the production of antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the Brookhaven AGS. We report invariant multiplicities for antiproton production in the kinematic region 1.4<y<2.2 and 50<p_T<300 MeV/c, and compare our data with a first collision scaling model and previously published results from the E878 collaboration. The differences between the E864 and E878 antiproton measurements and the implications for antihyperon production are discussed.