44 research outputs found
Performance of the electromagnetic and hadronic prototype segments of the ALICE Forward Calorimeter
We present the performance of a full-length prototype of the ALICE Forward
Calorimeter (FoCal). The detector is composed of a silicon-tungsten
electromagnetic sampling calorimeter with longitudinal and transverse
segmentation (FoCal-E) of about 20 and a hadronic
copper-scintillating-fiber calorimeter (FoCal-H) of about 5.
The data were taken between 2021 and 2023 at the CERN PS and SPS beam lines
with hadron (electron) beams up to energies of 350 (300) GeV. Regarding
FoCal-E, we report a comprehensive analysis of its response to minimum ionizing
particles across all pad layers. The longitudinal shower profile of
electromagnetic showers is measured with a layer-wise segmentation of 1.
As a projection to the performance of the final detector in electromagnetic
showers, we demonstrate linearity in the full energy range, and show that the
energy resolution fulfills the requirements for the physics needs.
Additionally, the performance to separate two-showers events was studied by
quantifying the transverse shower width. Regarding FoCal-H, we report a
detailed analysis of the response to hadron beams between 60 and 350 GeV. The
results are compared to simulations obtained with a Geant4 model of the test
beam setup, which in particular for FoCal-E are in good agreement with the
data. The energy resolution of FoCal-E was found to be lower than 3% at
energies larger than 100 GeV. The response of FoCal-H to hadron beams was found
to be linear, albeit with a significant intercept that is about factor 2 larger
than in simulations. Its resolution, which is non-Gaussian and generally larger
than in simulations, was quantified using the FWHM, and decreases from about
16% at 100 GeV to about 11% at 350 GeV. The discrepancy to simulations, which
is particularly evident at low hadron energies, needs to be further
investigated.Comment: 55 pages (without acronyms), 45 captioned figure
Spatiotemporal Effects of Sonoporation Measured by Real-Time Calcium Imaging
Published in PubMed Central on 01 March 2010To investigate the effects of sonoporation, spatiotemporal evolution of ultrasound-induced changes
in intracellular calcium ion concentration ([Ca2+]i) was determined using real time fura-2AM
fluorescence imaging. Monolayers of Chinese hamster ovary (CHO) cells were exposed to 1-MHz
ultrasound tone burst (0.2 s, 0.45 MPa) in the presence of Optison™ microbubbles. At extracellular
[Ca2+]o of 0.9 mM, ultrasound application generated both non-oscillating and oscillating (periods
12–30 s) transients (changes of [Ca2+]i in time) with durations of 100–180 s. Immediate [Ca2+]i
transients after ultrasound application were induced by ultrasound-mediated microbubble–cell
interactions. In some cases, the immediately-affected cells did not return to pre-ultrasound
equilibrium [Ca2+]i levels, thereby indicating irreversible membrane damage. Spatial evolution of
[Ca2+]i in different cells formed a calcium wave and was observed to propagate outward from the
immediately-affected cells at 7–20 μm/s over a distance greater than 200 μm, causing delayed
transients in cells to occur sometimes 60 s or more after ultrasound application. In calcium-free
solution, ultrasound-affected cells did not recover, consistent with the requirement of extracellular
Ca2+ for cell membrane recovery subsequent to sonoporation. In summary, ultrasound application
in the presence of Optison™ microbubbles can generate transient [Ca2+]i changes and oscillations at
a focal site and in surrounding cells via calcium waves that last longer than the ultrasound duration
and spread beyond the focal site. These results demonstrate the complexity of downstream effects
of sonoporation beyond the initial pore formation and subsequent diffusion-related transport through
the cellular membraneNational Institutes of Health R01CA116592Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84355/1/nihms99796.pd
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Purified phenolics from hydrothermal treatments of biomass: ability to protect sunflower bulk oil and model food emulsions from oxidation
The phenolic fractions released during hydrothermal treatment of selected feedstocks (corn cobs, eucalypt wood chips, almond shells, chestnut burs, and white grape pomace) were selectively recovered by extraction with ethyl acetate and washed with ethanol/water solutions. The crude extracts were purified by a relatively simple adsorption technique using a commercial polymeric, nonionic resin. Utilization of 96% ethanol as eluting agent resulted in 47.0-72.6% phenolic desorption, yielding refined products containing 49-60% w/w phenolics (corresponding to 30-58% enrichment with respect to the crude extracts). The refined extracts produced from grape pomace and from chestnut burs were suitable for protecting bulk oil and oil-in-water and water-in-oil emulsions. A synergistic action with bovine serum albumin in the emulsions was observed