55 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
The Bergen proton CT system
The Bergen proton Computed Tomography (pCT) is a prototype detector under construction. It aims to have the capability to track and measure ionsâ energy deposition to minimize uncertainty in proton treatment planning. It is a high granularity digital tracking calorimeter, where the first two layers will act as tracking layers to obtain positional information of the incoming particle. The remainder of the detector will act as a calorimeter. Beam tests have been performed with multiple beams. These tests have shown that the ALPIDE chip sensor can measure the deposited energy, making it possible for the sensors to distinguish between the tracks in the Digital Tracking Calorimeter (DTC)
Esters of (Hydroxymethyl)diorganylsllanes: Synthesis and Thermally Induced Rearrangement
Twenty silanes of the type RRSi(H)CHOR (A) were syn- and entropy of activation) of these reactions were studied by thesized {R, R = Me, Ph, 1-naphthyl, PhCH, MeSiCH; OR means of dĂŒferential scanning calorimetry (DSC). In addition, = OC(O)Me, OC(O)Ph, OC(O)CF , OS(0)CF, OP(O)Ph, the kinetics of all reactions were investigated by 1H-NMR OC(O)Cl, and studied for their thermal behaviour. The silanes spectroscopy. The transition state of the rearrangement was A undergo a thermally induced rearrangement to give the investigated by an ab initio study based on the model comcorresponding silanes RRSi(OR)Me (B). For compounds with pound HSiCHOC(O)H (-> MeHSiOC(O)H]. The theoretical OR3 = OC(O)Cl, an additional decarboxylation takes place to data and the experimentally obtained energetic and kinetic yield the chlorosilanes R1R2Si(Cl)Me. Except for the deriva- data are discussed in terms of mechanistic aspects of the retives with OR = OC(O)Cl, the energetic (reaction enthalpy) arrangement reaction A -> B. and kinetic data (reaction order, frequency factor, enthalpy ..
Soft sensor for monitoring biomass subpopulations in mammalian cell culture processes
ObjectivesBiomass subpopulations in mammalian cell culture processes cause impurities and influence productivity, which requires this critical process parameter to be monitored in real-time.ResultsFor this reason, a novel soft sensor concept for estimating viable, dead and lysed cell concentration was developed, based on the robust and cheap in situ measurements of permittivity and turbidity in combination with a simple model. It could be shown that the turbidity measurements contain information about all investigated biomass subpopulations. The novelty of the developed soft sensor is the real-time estimation of lysed cell concentration, which is directly correlated to process-related impurities such as DNA and host cell protein in the supernatant. Based on data generated by two fed-batch processes the developed soft sensor is described and discussed.ConclusionsThe presented soft sensor concept provides a tool for viable, dead and lysed cell concentration estimation in real-time with adequate accuracy and enables further applications with respect to process optimization and control
A test facility for fritted spargers of production-scale-bioreactors
The production of therapeutic proteins requires qualification of equipment components and appropriate validation procedures for all operations. Since protein productions are typically performed in bioreactors using aerobic cultivation processes air sparging is an essential factor. As recorded in literature, besides ring spargers and open pipe, sinter frits are often used as sparging elements in large scale bioreactors. Due to the manufacturing process these frits have a high lot-to-lot product variability. Experience shows this is a practical problem for use in production processes of therapeutic proteins, hence frits must be tested before they can be employed. The circumstance of checking quality and performance of frits as sparging elements was investigated and various possibilities have been compared. Criteria have been developed in order to evaluate the sparging performance under conditions comparable to those in production bioreactors. The oxygen mass transfer coefficient (kLa) was chosen as the evaluation criterion. It is well known as an essential performance measure for fermenters in the monoclonal antibody production. Therefore a test rig was constructed able to automatically test frit-spargers with respect to their kLa-values at various gas throughputs. Performance differences in the percent range could be detected
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 Optisonâą microbubbles. At extracellular
[Ca2+]o of 0.9 mM, ultrasound application generated both non-oscillating and oscillating (periods
12â30 s) transients (changes of [Ca2+]i in time) with durations of 100â180 s. Immediate [Ca2+]i
transients after ultrasound application were induced by ultrasound-mediated microbubbleâcell
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 7â20 ÎŒm/s over a distance greater than 200 ÎŒm, 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 Optisonâą 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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