21 research outputs found

    Loop Quantum Gravity and the The Planck Regime of Cosmology

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    The very early universe provides the best arena we currently have to test quantum gravity theories. The success of the inflationary paradigm in accounting for the observed inhomogeneities in the cosmic microwave background already illustrates this point to a certain extent because the paradigm is based on quantum field theory on the curved cosmological space-times. However, this analysis excludes the Planck era because the background space-time satisfies Einstein's equations all the way back to the big bang singularity. Using techniques from loop quantum gravity, the paradigm has now been extended to a self-consistent theory from the Planck regime to the onset of inflation, covering some 11 orders of magnitude in curvature. In addition, for a narrow window of initial conditions, there are departures from the standard paradigm, with novel effects, such as a modification of the consistency relation involving the scalar and tensor power spectra and a new source for non-Gaussianities. Thus, the genesis of the large scale structure of the universe can be traced back to quantum gravity fluctuations \emph{in the Planck regime}. This report provides a bird's eye view of these developments for the general relativity community.Comment: 23 pages, 4 figures. Plenary talk at the Conference: Relativity and Gravitation: 100 Years after Einstein in Prague. To appear in the Proceedings to be published by Edition Open Access. Summarizes results that appeared in journal articles [2-13

    Development of a Multivalent Subunit Vaccine against Tularemia Using Tobacco Mosaic Virus (TMV) Based Delivery System

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    Francisella tularensisis a facultative intracellular pathogen, and is the causative agent of a fatal human disease known as tularemia. F. tularensis is classified as a Category A Biothreat agent by the CDC based on its use in bioweapon programs by several countries in the past and its potential to be used as an agent of bioterrorism. No licensed vaccine is currently available for prevention of tularemia. In this study, we used a novel approach for development of a multivalent subunit vaccine against tularemia by using an efficient tobacco mosaic virus (TMV) based delivery platform. The multivalent subunit vaccine was formulated to contain a combination of F. tularensis protective antigens: OmpA-like protein (OmpA), chaperone protein DnaK and lipoprotein Tul4 from the highly virulent F. tularensisSchuS4 strain. Two different vaccine formulations and immunization schedules were used. The immunized mice were challenged with lethal (10xLD100) doses of F. tularensisLVS on day 28 of the primary immunization and observed daily for morbidity and mortality. Results from this study demonstrate that TMV can be used as a carrier for effective delivery of multiple F. tularensisantigens. TMV-conjugate vaccine formulations are safe and multiple doses can be administered without causing any adverse reactions in immunized mice. Immunization with TMV-conjugated F. tularensisproteins induced a strong humoral immune response and protected mice against respiratory challenges with very high doses of F. tularensis LVS. This study provides a proof-of-concept that TMV can serve as a suitable platform for simultaneous delivery of multiple protective antigens of F. tularensis. Refinement of vaccine formulations coupled with TMV-targeting strategies developed in this study will provide a platform for development of an effective tularemia subunit vaccine as well as a vaccination approach that may broadly be applicable to many other bacterial pathogens

    Exploring new physics frontiers through numerical relativity

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    The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

    Prevention of Neutrophil Migration Ameliorates Rat Lung Allograft Rejection

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    Chemokines activate and recruit specific leukocyte subpopulations. We sought to determine whether neutrophil migration, which can contribute to the development of ischemia-reperfusion injury, correlates with lung allograft rejection. Orthotopic left lung allotransplantation was performed from Brown Norway (donor) to Fisher 344 (recipient) rats. Because the role of activated neutrophils in the development of allograft rejection is believed to be biphasic, we used specific CXC receptor inhibition with antileukinate in 2 dosing regimens. Recipients were allocated into 4 groups; A (early administration) received 2 doses of antileukinate (10.0 mg/kg) intramuscularly 24 h before and immediately after transplantation; B (continuous administration) continuously received antileukinate intraperitoneally (10.0 mg/kg/day) for 7 days after surgery. Groups A or B were compared with individual controls that received PBS alone. The progression of rejection was assessed radiographically. Histologic evaluation of allograft rejection based on pathologic rejection grade, performed on day 7, demonstrated significantly lower histologic rejection in group B compared with the control group (2.1 ± 1.0 vs. 3.3 ± 0.5; P = 0.018), whereas there was no significant difference in group A compared with the control group. There were no significant differences between the aeration scores of groups A or B compared with their control groups. Our data suggest that neutrophils may play a promoting role in the development of allograft rejection, and blockage of neutrophil migration may suppress acute lung allograft rejection
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