Galactose-Functionalized PolyHIPE Scaffolds for Use in Routine Three Dimensional Culture of Mammalian Hepatocytes

Three-dimensional (3D) cell culture is regarded as a more physiologically relevant method of growing cells in the laboratory compared to traditional monolayer cultures. Recently, the application of polystyrene-based scaffolds produced using polyHIPE technology (porous polymers derived from high internal phase emulsions) for routine 3D cell culture applications has generated very promising results in terms of improved replication of native cellular function in the laboratory. These materials, which are now available as commercial scaffolds, are superior to many other 3D cell substrates due to their high porosity, controllable morphology, and suitable mechanical strength. However, until now there have been no reports describing the surface-modification of these materials for enhanced cell adhesion and function. This study, therefore, describes the surface functionalization of these materials with galactose, a carbohydrate known to specifically bind to hepatocytes via the asialoglycoprotein receptor (ASGPR), to further improve hepatocyte adhesion and function when growing on the scaffold. We first modify a typical polystyrene-based polyHIPE to produce a cell culture scaffold carrying pendent activated-ester functionality. This was achieved via the incorporation of pentafluorophenyl acrylate (PFPA) into the initial styrene (STY) emulsion, which upon polymerization formed a polyHIPE with a porosity of 92% and an average void diameter of 33 μm. Histological analysis showed that this polyHIPE was a suitable 3D scaffold for hepatocyte cell culture. Galactose-functionalized scaffolds were then prepared by attaching 2′-aminoethyl-β-D-galactopyranoside to this PFPA functionalized polyHIPE via displacement of the labile pentafluorophenyl group, to yield scaffolds with approximately ca. 7−9% surface carbohydrate. Experiments with primary rat hepatocytes showed that cellular albumin synthesis was greatly enhanced during the initial adhesion/settlement period of cells on the galactose-functionalized material, suggesting that the surface carbohydrates are accessible and selective to cells entering the scaffold. This porous polymer scaffold could, therefore, have important application as a 3D scaffold that offers enhanced hepatocyte adhesion and functionality

Four-point correlator constraints on electromagnetic chiral parameters and resonance effective Lagrangians

We pursue the analysis of a set of generalized DGMLY sum rules for the electromagnetic chiral parameters at order $e^2p^2$ and discuss implications for effective Lagrangians with resonances. We exploit a formalism in which charge spurions are introduced and treated as sources. We show that no inconsistency arises from anomalies up to quadratic order in the spurions. We focus on the sum rules associated with QCD 4-point correlators which were not analyzed in detail before. Convergence properties of the sum rules are deduced from a general analysis of the form of the counterterms in the presence of electromagnetic spurions. Following the approach in which vector and axial-vector resonances are described with antisymmetric tensor fields and have a chiral order, we show that the convergence constraints are violated at chiral order four and can be satisfied by introducing a set of terms of order six. The relevant couplings get completely and uniquely determined from a set of generalized Weinberg sum-rule relations. An update on the corrections to Dashen's low-energy theorem is given.Comment: 42 pages, 1 figure. v2: references adde

Physics Opportunities with the 12 GeV Upgrade at Jefferson Lab

This white paper summarizes the scientific opportunities for utilization of the upgraded 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF) and associated experimental equipment at Jefferson Lab. It is based on the 52 proposals recommended for approval by the Jefferson Lab Program Advisory Committee.The upgraded facility will enable a new experimental program with substantial discovery potential to address important topics in nuclear, hadronic, and electroweak physics.Comment: 64 page

The 2009 World Average of αs\alpha_s

Measurements of $\alpha_s$, the coupling strength of the Strong Interaction between quarks and gluons, are summarised and an updated value of the world average of $\alpha_s (M_Z)$ is derived. Building up on previous reviews, special emphasis is laid on the most recent determinations of $\alpha_s$. These are obtained from $\tau$-decays, from global fits of electroweak precision data and from measurements of the proton structure function \F_2, which are based on perturbative QCD calculations up to $O(\alpha_s^4)$; from hadronic event shapes and jet production in \epem annihilation, based on $O(\alpha_s^3)$ QCD; from jet production in deep inelastic scattering and from $\Upsilon$ decays, based on $O(\alpha_s^2)$ QCD; and from heavy quarkonia based on unquenched QCD lattice calculations. Applying pragmatic methods to deal with possibly underestimated errors and/or unknown correlations, the world average value of $\alpha_s (M_Z)$ results in $\alpha_s (M_Z) = 0.1184 \pm 0.0007$. The measured values of $\alpha_s (Q)$, covering energy scales from Q \equiv \mtau = 1.78 GeV to 209 GeV, exactly follow the energy dependence predicted by QCD and therefore significantly test the concept af Asymptotic Freedom.Comment: 14 pages, 7 figure

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Observation of a cusp-like structure in the pizero-pizero invariant mass distribution from K+- ==> pi+- pizero pizero decay and determination of the pi-pi scattering lengths

We report the results from a study of ~23 Million K+- ==> pi+- pizero pizero decays recorded by the NA48/2 experiment at the CERN SPS, showing an anomaly in the pizero pizero invariant mass distribution in the region around 2m+, where m+ is the charged pion mass. This anomaly, never observed in previous experiments, can be interpreted as an effect due mainly to the final state charge exchange scattering process pi+ pi- ==> pizero pizero in K+- ==> pi+- pi+ pi- decay. It provides a precise determination of a0 - a2, the difference between the pi-pi scattering lengths in the isospin I=0 and I=2 states.Comment: 16 pages, 7 figures Accepted for publication in Physics Letters

Prospects for e+e- physics at Frascati between the phi and the psi

We present a detailed study, done in the framework of the INFN 2006 Roadmap, of the prospects for e+e- physics at the Frascati National Laboratories. The physics case for an e+e- collider running at high luminosity at the phi resonance energy and also reaching a maximum center of mass energy of 2.5 GeV is discussed, together with the specific aspects of a very high luminosity tau-charm factory. Subjects connected to Kaon decay physics are not discussed here, being part of another INFN Roadmap working group. The significance of the project and the impact on INFN are also discussed. All the documentation related to the activities of the working group can be found in http://www.roma1.infn.it/people/bini/roadmap.html.Comment: INFN Roadmap Report: 86 pages, 25 figures, 9 table

The nuclear collective motion

Current developments in nuclear structure are discussed from a theoretical perspective. First, the progress in theoretical modeling of nuclei is reviewed. This is followed by the discussion of nuclear time scales, nuclear collective modes, and nuclear deformations. Some perspectives on nuclear structure research far from stability are given. Finally, interdisciplinary aspects of the nuclear many-body problem are outlined