Towards Quantum Cosmology without Singularities

In this paper we investigate the vanishing of cosmological singularities by quantization. Starting from a 5d Kaluza--Klein approach we quantize, as a first step, the non--spherical metric part and the dilaton field. These fields which are classically singular become smooth after quantization. In addition, we argue that the incorporation of non perturbative quantum corrections form a dilaton potential. Technically, the procedure corresponds to the quantization of 2d dilaton gravity and we discuss several models. From the 4d point of view this procedure is a semiclassical approach where only the dilaton and moduli matter fields are quantized.Comment: 9 pages, 2 figures, Latex, epsfig.sty, epsf.te

Large-area functionalized CVD graphene for work function matched transparent electrodes

PublishedArticleThe efficiency of flexible photovoltaic and organic light emitting devices is heavily dependent on the availability of flexible and transparent conductors with at least a similar workfunction to that of Indium Tin Oxide. Here we present the first study of the work function of large area (up to 9 cm2) FeCl3 intercalated graphene grown by chemical vapour deposition on Nickel, and demonstrate values as large as 5.1 eV. Upon intercalation, a charge density per graphene layer of 5 ⋅ 1013 ± 5 ⋅ 1012 cm−2 is attained, making this material an attractive platform for the study of plasmonic excitations in the infrared wavelength spectrum of interest to the telecommunication industry. Finally, we demonstrate the potential of this material for flexible electronics in a transparent circuit on a polyethylene naphthalate substrate.EPSRCRoyal Society international Exchanges Schem

Editoriale/Editorial/Éditorial/Editorial

Numero specialeDi nuove e vecchie schiavitù: storie di dominio, lotte per la libertà(a cura di) Thomas Casadei e Vincenzo Russ

Polymyxin B in Combination with Rifampin and Meropenem against Polymyxin B-Resistant KPC-Producing Klebsiella pneumoniae

Safe and effective therapies are urgently needed to treat polymyxin-resistant KPC-producing K. pneumoniae and suppress the emergence of resistance. We investigated the pharmacodynamics of polymyxin B, rifampin, and meropenem alone and as polymyxin B-based double and triple combinations against KPC-producing K. pneumoniae . The rate and extent of killing with polymyxin B (1-128mg/L), rifampin (2-16mg/L), and meropenem (10-120mg/L) were evaluated against polymyxin B-susceptible (PB S ) and -resistant (PB R ) clinical isolates using 48h static time-kills. Additionally, humanized triple drug regimens of polymyxin B (C ss : 0.5, 1, 2mg/L), rifampin 600mg every 12 or 8h, and meropenem 1 or 2g every 8h dosed as an extended 3h infusion were simulated over 48h using a one-compartment in vitro dynamic infection model. Serial bacterial counts were measured to quantify pharmacodynamic effect. Population analysis profiles (PAPs) were used to assess the emergence of polymyxin B resistance. Monotherapy was ineffective against both isolates. Polymyxin B with rifampin demonstrated early bactericidal activity against the PB S isolate followed by regrowth by 48h. Bactericidal activity was sustained at all polymyxin B concentrations ≥2 mg/L in combination with meropenem. No two-drug combinations were effective against the PB R isolate, but all simulated triple-drug regimens showed early bactericidal activity by 8h that was sustained over 48h against both strains. PAPs did not reveal the emergence of resistant subpopulations. The triple drug combination of polymyxin B, rifampin, and meropenem may be a viable consideration for the treatment of PB R KPC-producing K. pneumoniae . Further investigation is warranted to optimize triple combination therapy