131 research outputs found
Effects of three current provisional restoration materials on fibroblast viability
Poster presented at the First international Congress of CiiEM - From Basic Sciences to Clinical Research. Egas Moniz, Caparica, Portugal, 27-28 November 2015Egas Moniz Cooperativa de Ensino Superior CR
Cytotoxic and genotoxic effects of three cements used in fixed prosthesis
Poster presented at the First international Congress of CiiEM - From Basic Sciences to Clinical Research. Egas MOniz, Caparica, Portugal, 27-28 November 2015Egas Moniz - Cooperativa de Ensino Superior CR
Impact of massive neutrinos on the Higgs self-coupling and electroweak vacuum stability
The presence of right-handed neutrinos in the type I seesaw mechanism may
lead to significant corrections to the RG evolution of the Higgs self-coupling.
Compared to the Standard Model case, the Higgs mass window can become narrower,
and the cutoff scale become lower. Naively, these effects decrease with
decreasing right-handed neutrino mass. However, we point out that the unknown
Dirac Yukawa matrix may impact the vacuum stability constraints even in the low
scale seesaw case not far away from the electroweak scale, hence much below the
canonical seesaw scale of 10^15 GeV. This includes situations in which
production of right-handed neutrinos at colliders is possible. We illustrate
this within a particular parametrization of the Dirac Yukawas and with explicit
low scale seesaw models. We also note the effect of massive neutrinos on the
top quark Yukawa coupling, whose high energy value can be increased with
respect to the Standard Model case.Comment: 17 pages, 7 figures, minor revisions, version to appear in JHE
Measurement of the muon decay spectrum with the ICARUS liquid Argon TPC
Examples are given which prove the ICARUS detector quality through relevant
physics measurements. We study the muon decay energy spectrum from a sample of
stopping muon events acquired during the test run of the ICARUS T600 detector.
This detector allows the spatial reconstruction of the events with fine
granularity, hence, the precise measurement of the range and dE/dx of the muon
with high sampling rate. This information is used to compute the calibration
factors needed for the full calorimetric reconstruction of the events. The
Michel rho parameter is then measured by comparison of the experimental and
Monte Carlo simulated muon decay spectra, obtaining rho = 0.72 +/- 0.06(stat.)
+/- 0.08(syst.). The energy resolution for electrons below ~50 MeV is finally
extracted from the simulated sample, obtaining (Emeas-Emc)/Emc =
11%/sqrt(E[MeV]) + 2%.Comment: 16 pages, 8 figures, LaTex, A4. Some text and 1 figure added. Final
version as accepted for publication in The European Physical Journal
No supra-additive effects of goserelin and radiotherapy on clonogenic survival of prostate carcinoma cells in vitro
<p>Abstract</p> <p>Background</p> <p>Oncological results of radiotherapy for locally advanced prostate cancer (PC) are significantly improved by simultaneous application of LHRH analoga (e.g. goserelin). As 85% of PC express LHRH receptors, we investigated the interaction of goserelin incubation with radiotherapy under androgen-deprived conditions in vitro.</p> <p>Methods</p> <p>LNCaP and PC-3 cells were stained for LHRH receptors. Downstream the LHRH receptor, changes in protein expression of c-fos, phosphorylated p38 and phosphorylated ERK1/2 were analyzed by means of Western blotting after incubation with goserelin and irradiation with 4 Gy. Both cell lines were incubated with different concentrations of goserelin in hormone-free medium. 12 h later cells were irradiated (0 – 4 Gy) and after 12 h goserelin was withdrawn. Endpoints were clonogenic survival and cell viability (12 h, 36 h and 60 h after irradiation).</p> <p>Results</p> <p>Both tested cell lines expressed LHRH-receptors. Changes in protein expression demonstrated the functional activity of goserelin in the tested cell lines. Neither in LNCaP nor in PC-3 any significant effects of additional goserelin incubation on clonogenic survival or cell viability for all tested concentrations in comparison to radiation alone were seen.</p> <p>Conclusion</p> <p>The clinically observed increase in tumor control after combination of goserelin with radiotherapy in PC cannot be attributed to an increase in radiosensitivity of PC cells by goserelin in vitro.</p
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Yields and production rates of cosmogenic <sup>9</sup>Li and <sup>8</sup>He measured with the Double Chooz near and far detectors
The yields and production rates of the radioisotopes 9Li and 8He created by cosmic muon spallation on 12C, have been measured by the two detectors of the Double Chooz experiment. The identical detectors are located at separate sites and depths, which means that they are subject to different muon spectra. The near (far) detector has an overburden of ∼120 m.w.e. (∼300 m.w.e.) corresponding to a mean muon energy of 32.1 ± 2.0 GeV (63.7 ± 5.5 GeV). Comparing the data to a detailed simulation of the 9Li and 8He decays, the contribution of the 8He radioisotope at both detectors is found to be compatible with zero. The observed 9Li yields in the near and far detectors are 5.51 ± 0.51 and 7.90 ± 0.51, respectively, in units of 10−8μ−1g−1cm2. The shallow overburdens of the near and far detectors give a unique insight when combined with measurements by KamLAND and Borexino to give the first multi-experiment, data driven relationship between the 9Li yield and the mean muon energy according to the power law Y=Y0(〈Eμ〉/1GeV)α¯, giving α¯=0.72±0.06 and Y0 = (0.43 ± 0.11) × 10−8μ−1g−1cm2. This relationship gives future liquid scintillator based experiments the ability to predict their cosmogenic 9Li background rates
Spin decoherence and off-resonance behavior of radiofrequency-driven spin rotations in storage rings
Radiofrequency-driven resonant spin rotators are routinely used as standard
instruments in polarization experiments in particle and nuclear physics.
Maintaining the continuous exact parametric spin-resonance condition of the
equality of the spin rotator and the spin precession frequency during operation
constitutes one of the challenges. We present a detailed analytic description
of the impact of detuning the exact spin resonance on the vertical and the
in-plane precessing components of the polarization. An important part of the
formalism presented here is the consideration of experimentally relevant
spin-decoherence effects. We discuss applications of the developed formalism to
the interpretation of the experimental data on the novel pilot bunch approach
to control the spin-resonance condition during the operation of the
radiofrequency-driven Wien filter that is used as a spin rotator in the first
direct deuteron electric dipole moment measurement at COSY. We emphasize the
potential importance of the hitherto unexplored phase of the envelope of the
horizontal polarization as an indicator of the stability of the
radiofrequency-driven spin rotations in storage rings. The work presented here
serves as a satellite publication to the work published concurrently on the
proof of principle experiment about the so-called pilot bunch approach that was
developed to provide co-magnetometry for the deuteron electric dipole moment
experiment at COSY.Comment: 31 pages, 10 figures, 5 table
Pilot bunch and co-magnetometry of polarized particles stored in a ring
In polarization experiments at storage rings, one of the challenges is to
maintain the spin-resonance condition of a radio-frequency spin rotator with
the spin-precessions of the orbiting particles. Time-dependent variations of
the magnetic fields of ring elements lead to unwanted variations of the spin
precession frequency. We report here on a solution to this problem by shielding
(or masking) one of the bunches stored in the ring from the high-frequency
fields of the spin rotator, so that the masked pilot bunch acts as a
co-magnetometer for the other signal bunch, tracking fluctuations in the ring
on a time scale of about one second. While the new method was developed
primarily for searches of electric dipole moments of charged particles, it may
have far-reaching implications for future spin physics facilities, such as the
EIC and NICA.Comment: 5 pages, 3 figures + references + supplemental material (6 pages, 2
figures, 6 tables + references
Novel event classification based on spectral analysis of scintillation waveforms in Double Chooz
Liquid scintillators are a common choice for neutrino physics experiments, but their capabilities to perform background rejection by scintillation pulse shape discrimination is generally limited in large detectors. This paper describes a novel approach for a pulse shape based event classification developed in the context of the Double Chooz reactor antineutrino experiment. Unlike previous implementations, this method uses the Fourier power spectra of the scintillation pulse shapes to obtain event-wise information. A classification variable built from spectral information was able to achieve an unprecedented performance, despite the lack of optimization at the detector design level. Several examples of event classification are provided, ranging from differentiation between the detector volumes and an efficient rejection of instrumental light noise, to some sensitivity to the particle type, such as stopping muons, ortho-positronium formation, alpha particles as well as electrons and positrons. In combination with other techniques the method is expected to allow for a versatile and more efficient background rejection in the future, especially if detector optimization is taken into account at the design level
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