Heavy Quarkonia Production in p+p Collisions from the PHENIX Experiment

Quarkonia provide a sensitive probe of the properties of the hot dense medium created in high energy heavy ion collisions. Hard scattering processes result in the production of heavy quark pairs that interact with the collision medium during hadronization. These in-medium interactions convey information about the fundamental properties of the medium itself and can be used to examine the modification of the QCD confining potential in the collision environment. Baseline measurements from p+p and d+Au collision systems are used to distinguish cold nuclear matter effects while measurements from heavy ion collision systems are used to quantify in-medium effects. The PHENIX experiment has the capability of detecting heavy quarkonia at $1.2<|\eta|<2.2$ via the $\mu^+\mu^-$ decay channel and at $|\eta|<0.35$ via the $e^+e^-$ decay channel. Recent runs have resulted in the collection of high statistics p+p data sets that provide an essential baseline reference for heavy ion measurements and allow for further critical evaluation of heavy quarkonia production mechanisms. The latest PHENIX results for the production of the $J/\psi$ in p+p collisions are presented and future prospects for $\psi'$, $\chi_{c}$ and $\Upsilon$ measurements are discussed.Comment: 4 pages, 2 figures, Proceedings for Quark Matter 200

Improvement of leak tightness for swellable elastomeric seals through the shape optimization

Swellable packers have been widely employed in various oil & gas applications. Downhole conditions are difficult to reproduce using physical testing environments, but can be simulated in a virtual environment using CAE software. A better understanding of packers’ mechanical behaviour in downhole conditions would provide a higher confidence and improvement in existing engineering design practices for the manufacturing of packers. The numerical simulation can be incorporated into optimisation procedures searching for an optimal shape of packers aiming to minimise the time to seal the borehole and maximise the contact pressure between the seal and borehole. Such an optimisation would facilitate the development of a packer with various designs optimised for different downhole conditions. The objective of this work is to develop a design tool integrated into Abaqus/CAE to implement parametric numerical studies using implicit and explicit FE-simulations. However, development of such a CAE plugin is associated with a number of technical challenges specific to this class of multiphysics problems, which are addressed in this research and discussed in the paper

Assessment of leak tightness for swellable elastomeric seals considering fluid-structure interaction with the CEL approach

Swellable elastomeric seal is a type of specifically engineered packer that swell upon contact with wellbore fluids. Assessment of leakage tightness is a fundamental aspect in the design of swellable packers, since they should guarantee a reliable sealing under extreme pressures of the downhole fluids. Numerical capability of the leakage pressure prediction would facilitate improvement in the packer design methodology. Previous work was focused on investigation of the non-parametric optimisation capability seeking for an optimal external shape with a goal to maximise the grip of a packer with a borehole. The verification of an optimised design was done with a dynamic FE-simulation of packer's failure by extrusion under an excessive pressure. The downside of that verification analysis was that Abaqus/Explicit solver couldn't implement a realistic adaptive pressure application due to changing packer disposition and contact conditions. This simulation challenge is addressed in this paper by application of the Coupled Eulerian-Lagrangian (CEL) approach in Abaqus/Explicit, which provides the ability to simulate a class of problems where the fluid-structure interaction (FSI) is important

Experience with Community‐Based Amphotericin B Infusion Therapy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90368/1/phco.25.5.690.63591.pd

Diels–alder reactions of alkyl 2H-azirine-3-carboxylates with furans

Methyl 2-(2,6-dichlorophenyl)-2H-azirine-3-carboxylate 1 and furan give the aziridine 2 by a Diels–Alder cycloaddition reaction. The hydrolysis of compound 2 leads to a dihydrofuranol 11 by cleavage of a C–N bond. X-Ray crystal structures of compounds 2 and 11 have been determined. Compound 2 reacts with alcohols in a similar way to give 2-alkoxy-2,5-dihydrofurans as mixtures of cis and trans isomers. The structures of these compounds have been determined from an X-ray crystal structure of one of the methyl ethers, the trans isomer 13. The reaction of the azirine 1 with 1,3-diphenylisobenzofuran leads to the formation of two isomeric 1 : 1 adducts that have been identified as the products of endo and exo cycloaddition, 3 and 4. The endo isomer 3 is converted into the exo isomer 4 by heat. Similar Diels–Alder reactions have been carried out between furans and benzyl 2H-azirine-3-carboxylate 6. Hydrolysis of the adduct 7 formed with furan again produces a dihydrofuranol 25 as the major product together with three minor products, two of which are 1-azabicyclo[4.1.0]hept-3-ene-2,5-diols 27 and 28 that result from C–O bond cleavage. Protection of the mixture of alcohols with TBS triflate gives the bis(TBS) ether 31 of the trans-1-azabicyclo[4.1.0]hept-3-ene-2,5-diol as the major product, showing that this ring system can be produced from the dihydrofuranol 25. The bis(TBS) ether 30 of the cis-2,5-diol is a minor product and its structure has been established by independent synthesis through a Diels–Alder reaction between the azirine 6 and 1,4-bis(tert-butyldimethylsilyloxy)butadiene 32.Fundação para a Ciência e Tecnologia - POCTI/32723/QUI/2000. FEDER. EPSRC

Polyanionic Ligand Platforms for Methyl- and Dimethylaluminum Arrays

Trimethylaluminum finds widespread applications in chemical and materials synthesis, most prominently in its partially hydrolyzed form of methylalumoxane (MAO), which is used as a cocatalyst in the polymerization of olefins. This work investigates the sequential reactions of trimethylaluminum with hexaprotic phosphazenes (RNH)6P3N3 (=XH6) equipped with substituents R of varied steric bulk including tert-butyl (1H6), cyclohexyl (2H6), isopropyl (3H6), isobutyl (4H6), ethyl (5H6), propyl (6H6), methyl (7H6), and benzyl (8H6). Similar to MAO, the resulting complexes of polyanionic phosphazenates [XHn]n−6 accommodate multinuclear arrays of [AlMe2]+ and [AlMe]2+. Reactions were monitored by 31P NMR spectroscopy, and structures were determined by single-crystal X-ray diffraction. They included 1H4(AlMe2)2, 1H3(AlMe2)3, 2H3(AlMe2)3, 3(AlMe2)4AlMe, 4H­(AlMe2)5, 4(AlMe2)6, {5H­(AlMe2)4}2AlMe, 5(AlMe2)6, 6(AlMe2)6, {7(AlMe2)4AlMe}2, and 8(AlMe2)6. The study shows that subtle variations of the steric properties of the R groups influence the reaction pathways, levels of aggregation, and fluxional behavior. While [AlMe2]+ is the primary product of the metalation, [AlMe]2+ is utilized to alleviate overcrowding or to aid aggregation. At the later stages of metalation, [AlMe2]+ groups start to scramble around congested sites. The ligands proved to be very robust and extremely flexible, offering a unique platform to study complex multinuclear metal arrangements

Bioavailability and kidney responses to Diclofenac in the fathead minnow (Pimephales promelas)

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Diclofenac is one of the most widely prescribed nonsteroidal anti-inflammatory drugs worldwide. It is frequently detected in surface waters; however, whether this pharmaceutical poses a risk to aquatic organisms is debated. Here we quantified the uptake of diclofenac by the fathead minnow (Pimephales promelas) following aqueous exposure (0.2-25.0 μg L(-1)) for 21 days, and evaluated the tissue and biomolecular responses in the kidney. Diclofenac accumulated in a concentration- and time-dependent manner in the plasma of exposed fish. The highest plasma concentration observed (for fish exposed to 25 μg L(-1) diclofenac) was within the therapeutic range for humans. There was a strong positive correlation between exposure concentration and the number of developing nephrons observed in the posterior kidney. Diclofenac was not found to modulate the expression of genes in the kidney associated with its primary mode of action in mammals (prostaglandin-endoperoxide synthases) but modulated genes associated with kidney repair and regeneration. There were no significant adverse effects following 21 days exposure to concentrations typical of surface waters. The combination of diclofenac's uptake potential, effects on kidney nephrons and relatively small safety margin for some surface waters may warrant a longer term chronic health effects analysis for diclofenac in fish.This work was funded by Knowledge Transfer Partnership (KTP): Use of ‘omic’ technologies in the environmental risk assessment of pharmaceuticals (KTP007650) and AstraZeneca’s Safety, Health and Environment (SHE) Research Programme. We thank Lina Gunnarsson, Matt Winter and James Cresswell (Exeter University), and former members of the Brixham Environmental Laboratory for their advice and assistance. Authors declare no competing financial interest

MRI channel flows and their parasites

Local simulations of the magnetorotational instability (MRI) in accretion disks can exhibit recurrent coherent structures called channel flows. The formation and destruction of these structures may play a role in the development and saturation of MRI-induced turbulence, and consequently help us understand the time-dependent accretion behaviour of certain astrophysical objects. Previous investigations have revealed that channel solutions are attacked by various parasitic modes, foremost of which is an analogue of the Kelvin-Helmholtz instability. We revisit these instabilities and show how they relate to the classical instabilities of plasma physics, the kink and pinch modes. However, we argue that in most cases channels emerge from developed turbulence and are eventually destroyed by turbulent mixing, not by the parasites. The exceptions are the clean isolated channels which appear in systems near criticality or which emerge from low amplitude initial conditions. These structures inevitably achieve large amplitudes and are only then destroyed, giving rise to eruptive behaviour.Comment: 17 pages, 17 figures, accepted by MNRA

Transverse Spin at PHENIX: Results and Prospects

The Relativistic Heavy Ion Collider (RHIC), as the world's first and only polarized proton collider, offers a unique environment in which to study the spin structure of the proton. In order to study the proton's transverse spin structure, the PHENIX experiment at RHIC took data with transversely polarized beams in 2001-02 and 2005, and it has plans for further running with transverse polarization in 2006 and beyond. Results from early running as well as prospective measurements for the future will be discussed.Comment: 6 pages, 2 figures, presented at Transversity 2005, Como, Ital

Collision geometry scaling of Au+Au pseudorapidity density from sqrt(s_NN) = 19.6 to 200 GeV

The centrality dependence of the midrapidity charged particle multiplicity in Au+Au collisions at sqrt(s_NN) = 19.6 and 200 GeV is presented. Within a simple model, the fraction of hard (scaling with number of binary collisions) to soft (scaling with number of participant pairs) interactions is consistent with a value of x = 0.13 +/- 0.01(stat) +/- 0.05(syst) at both energies. The experimental results at both energies, scaled by inelastic p(pbar)+p collision data, agree within systematic errors. The ratio of the data was found not to depend on centrality over the studied range and yields a simple linear scale factor of R_(200/19.6) = 2.03 +/- 0.02(stat) +/- 0.05(syst).Comment: 5 pages, 4 figures, submitted to PRC-R