Exactly solvable charged dilaton gravity theories in two dimensions

We find exactly solvable dilaton gravity theories containing a U(1) gauge field in two dimensional space-time. The classical general solutions for the gravity sector (the metric plus the dilaton field) of the theories coupled to a massless complex scalar field are obtained in terms of the stress-energy tensor and the U(1) current of the scalar field. We discuss issues that arise when we attempt to use these models for the study of the gravitational back-reaction.Comment: The introductory part is changed. a version to appear in Class. Quant. Grav. 6 pages, RevTe

Mercury and Water Quality Study. Impact of Gold Mining in Song Bung 4 Project Area, Central Vietnam

Årsliste 2006The aim of this study is to elucidate any impact that the mining activity in the catchment of Song Bung River has on the water quality, sediment quality, as well as for the fish and the fish flesh quality in the mainstream river and in some tributaries in the Song Bung 4 hydropower development project area. In Song Bung mainstream enhanced concentrations of mercury were found both in the water and in the sediments in the river stretch where gold dredging activity was carried out. The concentrations were however low, much lower than problem levels both in national and internationally recognized environmental quality guidelines. This also applied for the tributaries. For arsenic and all other heavy metals normally confined with mining activity, observed concentrations were all lower than levels known to give environmental or consumption concerns. In the downstream part of the tributaries no traces of cyanide pollution were detected. The concentrations of mercury and other heavy metals in fish flesh were all low, and well below the WHO standards for consumption. The sediment dredging had only moderate impact on river water turbidity. However, the dredging made large physical disturbances of river habitats in the dredged sections of the rivers. Otherwise the water quality of Song Bung River was good and was to a low degree impacted by human activities. The mercury pollution of river sediments from the gold mining was so small that it will not create problems in the planned reservoir of Song Bung 4 Hydropower plant.Asian Development Ban

Infinite Lorentz boost along the M-theory circle and non-asymptotically flat solutions in supergravities

Certain non-asymptotically flat but supersymmetric classical solution of the type IIA supergravity can be interpreted as the infinitely-boosted version of the D-particle solution along the M-theory circle. By a chain of T-dual transformations, this analysis also applies to yield non-asymptotically flat solutions from the asymptotically flat and (non)-extremal solutions with intersecting D-strings and D five-branes of the type IIB supergravity compactified on a five-torus. Under S-duality, the non-asymptotically flat solutions in this context can in particular be used to describe the (1+1)-dimensional CGHS type black holes via spontaneous compactifications.Comment: 14 pages, Revte

Dose-adapted post-transplant cyclophosphamide for HLA-haploidentical transplantation in Fanconi anemia.

We developed a haploidentical transplantation protocol with post-transplant cyclophosphamide (CY) for in vivo T-cell depletion (TCD) using a novel adapted-dosing schedule (25 mg/kg on days +3 and +4) for Fanconi anemia (FA). With median follow-up of 3 years (range, 37 days to 6.2 years), all six patients engrafted. Two patients with multiple pre-transplant comorbidities died, one from sepsis and one from sepsis with associated chronic GVHD. Four patients without preexisting comorbidities and early transplant referrals are alive with 100% donor chimerism and excellent performance status. We conclude that adjusted-dosing post-transplant CY is effective in in vivo TCD to promote full donor engraftment in patients with FA

Invasion of the central nervous system by Cryptococcus neoformans requires a secreted fungal metalloprotease.

UnlabelledCryptococcus spp. cause life-threatening fungal infection of the central nervous system (CNS), predominantly in patients with a compromised immune system. Why Cryptococcus neoformans has this remarkable tropism for the CNS is not clear. Recent research on cerebral pathogenesis of C. neoformans revealed a predominantly transcellular migration of cryptococci across the brain endothelium; however, the identities of key fungal virulence factors that function specifically to invade the CNS remain unresolved. Here we found that a novel, secreted metalloprotease (Mpr1) that we identified in the extracellular proteome of C. neoformans (CnMpr1) is required for establishing fungal disease in the CNS. Mpr1 belongs to a poorly characterized M36 class of fungalysins that are expressed in only some fungal species. A strain of C. neoformans lacking the gene encoding Mpr1 (mpr1Δ) failed to breach the endothelium in an in vitro model of the human blood-brain barrier (BBB). A mammalian host infected with the mpr1Δ null strain demonstrated significant improvement in survival due to a reduced brain fungal burden and lacked the brain pathology commonly associated with cryptococcal disease. The in vivo studies further indicate that Mpr1 is not required for fungal dissemination and Mpr1 likely targets the brain endothelium specifically. Remarkably, the sole expression of CnMPR1 in Saccharomyces cerevisiae resulted in a robust migration of yeast cells across the brain endothelium, demonstrating Mpr1's specific activity in breaching the BBB and suggesting that Mpr1 may function independently of the hyaluronic acid-CD44 pathway. This distinct role for Mpr1 may develop into innovative treatment options and facilitate a brain-specific drug delivery platform.ImportanceCryptococcus neoformans is a medically relevant fungal pathogen causing significant morbidity and mortality, particularly in immunocompromised individuals. An intriguing feature is its strong neurotropism, and consequently the hallmark of cryptococcal disease is a brain infection, cryptococcal meningoencephalitis. For C. neoformans to penetrate the central nervous system (CNS), it first breaches the blood-brain barrier via a transcellular pathway; however, the identities of fungal factors required for this transmigration remain largely unknown. In an effort to identify extracellular fungal proteins that could mediate interactions with the brain endothelium, we undertook a proteomic analysis of the extracellular proteome and identified a secreted metalloprotease (Mpr1) belonging to the M36 class of fungalysins. Here we found that Mpr1 promotes migration of C. neoformans across the brain endothelium and into the CNS by facilitating attachment of cryptococci to the endothelium surface, thus underscoring the critical role of M36 proteases in fungal pathogenesis

Preclinical correction of human Fanconi anemia complementation group A bone marrow cells using a safety-modified lentiviral vector.

One of the major hurdles for the development of gene therapy for Fanconi anemia (FA) is the increased sensitivity of FA stem cells to free radical-induced DNA damage during ex vivo culture and manipulation. To minimize this damage, we have developed a brief transduction procedure for lentivirus vector-mediated transduction of hematopoietic progenitor cells from patients with Fanconi anemia complementation group A (FANCA). The lentiviral vector FancA-sW contains the phosphoglycerate kinase promoter, the FANCA cDNA, and a synthetic, safety-modified woodchuck post transcriptional regulatory element (sW). Bone marrow mononuclear cells or purified CD34(+) cells from patients with FANCA were transduced in an overnight culture on recombinant fibronectin peptide CH-296, in low (5%) oxygen, with the reducing agent, N-acetyl-L-cysteine (NAC), and a combination of growth factors, granulocyte colony-stimulating factor (G-CSF), Flt3 ligand, stem cell factor, and thrombopoietin. Transduced cells plated in methylcellulose in hypoxia with NAC showed increased colony formation compared with 21% oxygen without NAC (P<0.03), showed increased resistance to mitomycin C compared with green fluorescent protein (GFP) vector-transduced controls (P<0.007), and increased survival. Thus, combining short transduction and reducing oxidative stress may enhance the viability and engraftment of gene-corrected cells in patients with FANCA

Superstrings and D-branes in A Plane Wave

We carefully analyze the supersymmetry algebra of closed strings and open strings in a type IIB plane wave background. We use eight component chiral spinors, SO(8) Majorana-Weyl spinors, in light-cone gauge to provide a useful basis of string field theory calculation in the plane wave. We consider the two classes of D-branes, $D_\pm$-branes, and give a worldsheet derivation of conserved supercurrents for all half BPS D-branes preserving 16 supersymmetries in the type IIB plane wave background. We exhaustively provide the supersymmetry algebra of the half BPS branes as well. We also point out that the supersymmetry algebra distinguishes the two SO(4) directions with relative sign which is consistent with the Z_2 symmetry of the string action.Comment: v4: 28 pages, Latex, Worldsheet derivation of conserved supercurrents for all half BPS D-branes newly added, improved presentation and typo

Relating Quantum Information to Charged Black Holes

Quantum non-cloning theorem and a thought experiment are discussed for charged black holes whose global structure exhibits an event and a Cauchy horizon. We take Reissner-Norstr\"{o}m black holes and two-dimensional dilaton black holes as concrete examples. The results show that the quantum non-cloning theorem and the black hole complementarity are far from consistent inside the inner horizon. The relevance of this work to non-local measurements is briefly discussed.Comment: 14 pages, 2 figure

Quantum metric fluctuations and Hawking radiation

In this Letter we study the gravitational interactions between outgoing configurations giving rise to Hawking radiation and in-falling configurations. When the latter are in their ground state, the near horizon interactions lead to collective effects which express themselves as metric fluctuations and which induce dissipation, as in Brownian motion. This dissipation prevents the appearance of trans-Planckian frequencies and leads to a description of Hawking radiation which is very similar to that obtained from sound propagation in condensed matter models.Comment: 4 pages, revte

Hawking Radiation from Feynman Diagrams

The aim of this letter is to clarify the relationships between Hawking radiation and the scattering of light by matter falling into a black hole. To this end we analyze the S-matrix elements of a model composed of a massive infalling particle (described by a quantized field) and the radiation field. These fields are coupled by current-current interactions and propagate in the Schwarzschild geometry. As long as the photons energy is much smaller than the mass of the infalling particle, one recovers Hawking radiation since our S-matrix elements identically reproduce the Bogoliubov coefficients obtained by treating the trajectory of the infalling particle classically. But after a brief period, the energy of the `partners' of Hawking photons reaches this mass and the production of thermal photons through these interactions stops. The implications of this result are discussed.Comment: 12 pages, revtex, no figure