423 research outputs found

    A Potential Alternative Orodispersible Formulation to Prednisolone Sodium Phosphate Orally Disintegrating Tablets

    Get PDF
    The orally disintegrating tablet (ODT) has shown vast potential as an alternative oral dosage form to conventional tablets wherein they can disintegrate rapidly (≤30 s) upon contact with saliva fluid and should have an acceptable mouthfeel as long as their weight doesn’t exceed 500 mg. However, owing to the bitterness of several active ingredients, there is a need to find a suitable alternative to ODTs that maintains their features and can be taste-masked more simply and inexpensively. Therefore, electrospun nanofibers and solvent-cast oral dispersible films (ODFs) are used in this study as potential OD formulations for prednisolone sodium phosphate (PSP) that is commercially available as ODTs. The encapsulation efficiency (EE%) of the ODFs was higher (≈100%) compared to the nanofibers (≈87%), while the disintegration time was considerably faster for the electrospun nanofibers (≈30 s) than the solvent-cast ODFs (≈700 s). Hence, accelerated release rate of PSP from the nanofibers was obtained, due to their higher surface area and characteristic surface morphology that permitted higher wettability and thus, faster erosion. Taste-assessment study using the electronic-tongue quantified the bitterness threshold of the drug and its aversiveness concentration (2.79 mM). Therefore, a taste-masking strategy would be useful when further formulating PSP as an OD formulation

    Properties of hot and dense matter from relativistic heavy ion collisions

    Full text link
    We review the progress achieved in extracting the properties of hot and dense matter from relativistic heavy ion collisions at the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory and the large hadron collider (LHC) at CERN. We focus on bulk properties of the medium, in particular the evidence for thermalization, aspects of the equation of state, transport properties, as well as fluctuations and correlations. We also discuss the in-medium properties of hadrons with light and heavy quarks, and measurements of dileptons and quarkonia. This review is dedicated to the memory of Gerald E. Brown

    Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and ϕ\phi meson in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

    Full text link
    We present high precision measurements of elliptic flow near midrapidity (y<1.0|y|<1.0) for multi-strange hadrons and ϕ\phi meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy sNN=\sqrt{s_{NN}}= 200 GeV. We observe that the transverse momentum dependence of ϕ\phi and Ω\Omega v2v_{2} is similar to that of π\pi and pp, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30%\% and 30-80%\% collision centrality. There is an indication of the breakdown of previously observed mass ordering between ϕ\phi and proton v2v_{2} at low transverse momentum in the 0-30%\% centrality range, possibly indicating late hadronic interactions affecting the proton v2v_{2}.Comment: 7 pages and 4 figures, Accepted for publication in Physical Review Letter

    Energy dependence of acceptance-corrected dielectron excess mass spectrum at mid-rapidity in Au+Au collisions at sNN=19.6\sqrt{s_{NN}} = 19.6 and 200 GeV

    Get PDF
    The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity yee<1|y_{ee}|<1 in minimum-bias Au+Au collisions at sNN\sqrt{s_{NN}} = 19.6 and 200 GeV. The excess mass spectra are consistently described by a model calculation with a broadened ρ\rho spectral function for Mee<1.1M_{ee}<1.1 GeV/c2c^{2}. The integrated dielectron excess yield at sNN\sqrt{s_{NN}} = 19.6 GeV for 0.4<Mee<0.750.4<M_{ee}<0.75 GeV/c2c^2, normalized to the charged particle multiplicity at mid-rapidity, has a value similar to that in In+In collisions at sNN\sqrt{s_{NN}} = 17.3 GeV. For sNN\sqrt{s_{NN}} = 200 GeV, the normalized excess yield in central collisions is higher than that at sNN\sqrt{s_{NN}} = 17.3 GeV and increases from peripheral to central collisions. These measurements indicate that the lifetime of the hot, dense medium created in central Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV is longer than those in peripheral collisions and at lower energies.Comment: 9 pages, 6 figure

    Elliptic flow of electrons from heavy-flavor hadron decays in Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200, 62.4, and 39 GeV

    Full text link
    We present measurements of elliptic flow (v2v_2) of electrons from the decays of heavy-flavor hadrons (eHFe_{HF}) by the STAR experiment. For Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200 GeV we report v2v_2, for transverse momentum (pTp_T) between 0.2 and 7 GeV/c using three methods: the event plane method (v2v_{2}{EP}), two-particle correlations (v2v_2{2}), and four-particle correlations (v2v_2{4}). For Au+Au collisions at sNN\sqrt{s_{\rm NN}} = 62.4 and 39 GeV we report v2v_2{2} for pT<2p_T< 2 GeV/c. v2v_2{2} and v2v_2{4} are non-zero at low and intermediate pTp_T at 200 GeV, and v2v_2{2} is consistent with zero at low pTp_T at other energies. The v2v_2{2} at the two lower beam energies is systematically lower than at sNN=\sqrt{s_{\rm NN}} = 200 GeV for pT<1p_T < 1 GeV/c. This difference may suggest that charm quarks interact less strongly with the surrounding nuclear matter at those two lower energies compared to sNN=200\sqrt{s_{\rm NN}} = 200 GeV.Comment: Version accepted by PR

    Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions

    Get PDF
    We present measurements of π\pi^- and π+\pi^+ elliptic flow, v2v_2, at midrapidity in Au+Au collisions at sNN=\sqrt{s_{_{\rm NN}}} = 200, 62.4, 39, 27, 19.6, 11.5 and 7.7 GeV, as a function of event-by-event charge asymmetry, AchA_{ch}, based on data from the STAR experiment at RHIC. We find that π\pi^- (π+\pi^+) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at sNN=27 GeV\sqrt{s_{_{\rm NN}}} = \text{27 GeV} and higher. At sNN=200 GeV\sqrt{s_{_{\rm NN}}} = \text{200 GeV}, the slope of the difference of v2v_2 between π\pi^- and π+\pi^+ as a function of AchA_{ch} exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.Comment: 6 pages, 4 figure

    Azimuthal anisotropy in U+U and Au+Au collisions at RHIC

    Full text link
    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2}v_2\{2\} and v2{4}v_2\{4\}, for charged hadrons from U+U collisions at sNN\sqrt{s_{\rm NN}} = 193 GeV and Au+Au collisions at sNN\sqrt{s_{\rm NN}} = 200 GeV. Nearly fully overlapping collisions are selected based on the amount of energy deposited by spectators in the STAR Zero Degree Calorimeters (ZDCs). Within this sample, the observed dependence of v2{2}v_2\{2\} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. An initial-state model with gluon saturation describes the slope of v2{2}v_2\{2\} as a function of multiplicity in central collisions better than one based on Glauber with a two-component multiplicity model.Comment: Final paper version accepted for publication in Phys. Rev. Lett. New version includes comparisons to a constituent quark glauber mode

    Observation of Transverse Spin-Dependent Azimuthal Correlations of Charged Pion Pairs in p+pp^\uparrow+p at s=200\sqrt{s}=200 GeV

    Full text link
    We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p+pp^\uparrow+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of five standard deviations at high transverse momenta, at high pseudorapidities eta>0.5, and for pair masses around the mass of the rho-meson. This is the first direct transversity measurement in p+p collisions. Comparing the results to data from lepton-nucleon scattering will test the universality of these spin-dependent quantities.Comment: 11 pages, 5 figures, 15 tables. Submitted to PR

    Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at sqrt(s)= 7.7--62.4 GeV

    Full text link
    Elliptic flow (v_2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at sqrt{s_{NN}}= 7.7--62.4 GeV are presented for three centrality classes. The centrality dependence and the data at sqrt{s_{NN}}= 14.5 GeV are new. Except at the lowest beam energies we observe a similar relative v_2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v_2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with A Multiphase Transport Model and fit with a Blast Wave model.Comment: 14 pages, 12 figures, Phys. Rev. C, to be published. Data tables available at https://drupal.star.bnl.gov/STAR/publications/centrality-dependence-identified-particle-elliptic-flow-relativistic-heavy-ion-collisi

    Long-range pseudorapidity dihadron correlations in dd+Au collisions at sNN=200\sqrt{s_{\rm NN}}=200 GeV

    Get PDF
    Dihadron angular correlations in dd+Au collisions at sNN=200\sqrt{s_{\rm NN}}=200 GeV are reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (Δη\Delta\eta) on the near side (i.e. relative azimuth Δϕ0\Delta\phi\sim0). This correlated yield as a function of Δη\Delta\eta appears to scale with the dominant, primarily jet-related, away-side (Δϕπ\Delta\phi\sim\pi) yield. The Fourier coefficients of the Δϕ\Delta\phi correlation, Vn=cosnΔϕV_{n}=\langle\cos n\Delta\phi\rangle, have a strong Δη\Delta\eta dependence. In addition, it is found that V1V_{1} is approximately inversely proportional to the mid-rapidity event multiplicity, while V2V_{2} is independent of it with similar magnitude in the forward (dd-going) and backward (Au-going) directions.Comment: 8 pages, 4 figure
    corecore