119 research outputs found
High Yield Production Process for Shigella Outer Membrane Particles
Gram-negative bacteria naturally shed particles that consist of outer membrane lipids, outer membrane proteins, and soluble periplasmic components. These particles have been proposed for use as vaccines but the yield has been problematic. We developed a high yielding production process of genetically derived outer membrane particles from the human pathogen Shigella sonnei. Yields of approximately 100 milligrams of membrane-associated proteins per liter of fermentation were obtained from cultures of S. sonnei ÎtolR ÎgalU at optical densities of 30â45 in a 5 L fermenter. Proteomic analysis of the purified particles showed the preparation to primarily contain predicted outer membrane and periplasmic proteins. These were highly immunogenic in mice. The production of these outer membrane particles from high density cultivation of bacteria supports the feasibility of scaling up this approach as an affordable manufacturing process. Furthermore, we demonstrate the feasibility of using this process with other genetic manipulations e.g. abolition of O antigen synthesis and modification of the lipopolysaccharide structure in order to modify the immunogenicity or reactogenicity of the particles. This work provides the basis for a large scale manufacturing process of Generalized Modules of Membrane Antigens (GMMA) for production of vaccines from Gram-negative bacteria
Measurement of neutral current single production on argon with the MicroBooNE detector
We report the first measurement of production in neutral current (NC)
interactions on argon with average neutrino energy of ~GeV. We use
data from the MicroBooNE detector's 85-tonne active volume liquid argon time
projection chamber situated in Fermilab's Booster Neutrino Beam and exposed to
protons on target for this measurement. Measurements of NC
events are reported for two exclusive event topologies without charged
pions. Those include a topology with two photons from the decay of the
and one proton and a topology with two photons and zero protons. Flux-averaged
cross-sections for each exclusive topology and for their semi-inclusive
combination are extracted (efficiency-correcting for two-plus proton final
states), and the results are compared to predictions from the \textsc{genie},
\textsc{neut}, and \textsc{NuWro} neutrino event generators. We measure cross
sections of (syst) (stat), ,
and for the
semi-inclusive NC, exclusive NC+1p, and exclusive NC+0p
processes, respectively.Comment: 16 pages, 14 figures, 2 table
New CC0\pi\ GENIE Model Tune for MicroBooNE
A novel tune has been made for the MicroBooNE experiment. The fit uses 4 new
parameters within the GENIE v3.0.6 Monte Carlo program. Charged current
pionless data from the T2K experiment was used. New uncertainties were
obtained. These results will be used in future MicroBooNE analyses.Comment: 24 pages, 14 figure
Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment
The Deep Underground Neutrino Experiment (DUNE) will produce world-leading
neutrino oscillation measurements over the lifetime of the experiment. In this
work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in
the neutrino sector, and to resolve the mass ordering, for exposures of up to
100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed
uncertainties on the flux prediction, the neutrino interaction model, and
detector effects. We demonstrate that DUNE will be able to unambiguously
resolve the neutrino mass ordering at a 3 (5) level, with a 66
(100) kt-MW-yr far detector exposure, and has the ability to make strong
statements at significantly shorter exposures depending on the true value of
other oscillation parameters. We also show that DUNE has the potential to make
a robust measurement of CPV at a 3 level with a 100 kt-MW-yr exposure
for the maximally CP-violating values \delta_{\rm CP}} = \pm\pi/2.
Additionally, the dependence of DUNE's sensitivity on the exposure taken in
neutrino-enhanced and antineutrino-enhanced running is discussed. An equal
fraction of exposure taken in each beam mode is found to be close to optimal
when considered over the entire space of interest
Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC
DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6Â Ă Â 6Â Ă Â 6Â m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7Â m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties
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