428 research outputs found
Radiation Damage Studies of Silicon Photomultipliers
We report on the measurement of the radiation hardness of silicon
photomultipliers (SiPMs) manufactured by
Fondazione Bruno Kessler in Italy (1 mm and 6.2 mm), Center of
Perspective Technology and Apparatus in Russia (1 mm and 4.4 mm), and
Hamamatsu Corporation in Japan (1 mm). The SiPMs were irradiated using a
beam of 212 MeV protons at Massachusetts General Hospital, receiving fluences
of up to protons per cm with the SiPMs at operating
voltage. Leakage currents were read continuously during the irradiation. The
delivery of the protons was paused periodically to record scope traces in
response to calibrated light pulses to monitor the gains, photon detection
efficiencies, and dark counts of the SiPMs. The leakage current and dark noise
are found to increase with fluence. Te leakage current is found to be
proportional to the mean square deviation of the noise distribution, indicating
the dark counts are due to increased random individual pixel activation, while
SiPMs remain fully functional as photon detectors. The SiPMs are found to
anneal at room temperature with a reduction in the leakage current by a factor
of 2 in about 100 days.Comment: 35 pages, 25 figure
SiPM and front-end electronics development for Cherenkov light detection
The Italian Institute of Nuclear Physics (INFN) is involved in the
development of a demonstrator for a SiPM-based camera for the Cherenkov
Telescope Array (CTA) experiment, with a pixel size of 66 mm. The
camera houses about two thousands electronics channels and is both light and
compact. In this framework, a R&D program for the development of SiPMs suitable
for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different
photosensors have been produced at Fondazione Bruno Kessler (FBK), with
different micro-cell dimensions and fill factors, in different geometrical
arrangements. At the same time, INFN is developing front-end electronics based
on the waveform sampling technique optimized for the new NUV SiPM. Measurements
on 11 mm, 33 mm, and 66 mm NUV SiPMs
coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Verificação da capacidade de aprendizado de atividades motoras especĂficas envolvendo membros superiores e inferiores em pacientes portadores de disfunção cerebelar
Oral carcinogenesis biomarkers in Oral Chronic Mechanical Irritation-associated lesions
Previous works of our team had shown clinical data which suggest that Chronic Mechanical Irritation (CMI) could be a risk factor for Oral Cancer (OC). However, there are no known patterns of biomarkers in CMI indicative of cellular malignancy. The aim of this study was to identify a biomarker pattern of differentiation (Ck19) and cell proliferation (Ki67) in CMI-associated lesions, similar to those observed in OC. Methods: a Cross-sectional study of adult patients (n = 61), both sexes, with lesions associated with CMI according to the Piemonte et al criteria. CK19 and Ki67 Immunohistochemistry were carried out in biopsies of both types of lesions and the patterns were described according to previous publications of Safadi and Argyris. The present study was approved by Ethics Committee of the College of Dentistry, Universidad Nacional de Cordoba. Results: Ki67 overexpression and a CK19 focal pattern with strong intensity in basal and parabasal cells were observed in CMI lesions, similar to that observed in OC. Conclusion: there is no scientific literature on biomarker patterns of Oral CMI. Therefore, the described pattern, particularly Ck19, is novel and could be indicative of the relationship between the presence of CMI and oral carcinogenesis.Fil: Gilligan, Gerardo Marcelo. Universidad Nacional de CĂłrdoba. Facultad de OdontologĂa. Cátedra de EstomatologĂa A; Argentina.Fil: Piemonte, Eduardo David. Universidad Nacional de CĂłrdoba. Facultad de OdontologĂa. Cátedra de EstomatologĂa A; Argentina.Fil: Panico, RenĂ© Luis. Universidad Nacional de CĂłrdoba. Facultad de OdontologĂa. Cátedra de EstomatologĂa A; Argentina.Fil: Di Tada, Cecilia E. FundaciĂłn para el progreso de la Medicina; Argentina.Fil: Di Tada, Cecilia E.. Universidad Nacional de CĂłrdoba. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro de Investigaciones en QuĂmica BiolĂłgica; Argentina.Fil: Brunotto, Mabel. Universidad Nacional de CĂłrdoba. Facultad de OdontologĂa. Cátedra BiologĂa Celular A; Argentina.Otras Ciencias de la Salu
Elaboração de um programa de acompanhamento fisioterápico para pacientes portadores de esclerose lateral amiotrófica
Beam test results of the irradiated Silicon Drift Detector for ALICE
The Silicon Drift Detectors will equip two of the six cylindrical layers of
high precision position sensitive detectors in the ITS of the ALICE experiment
at LHC. In this paper we report the beam test results of a SDD irradiated with
1 GeV electrons. The aim of this test was to verify the radiation tolerance of
the device under an electron fluence equivalent to twice particle fluence
expected during 10 years of ALICE operation.Comment: 6 pages,6 figures, to appear in the proceedings of International
Workshop In high Multiplicity Environments (TIME'05), 3-7 October 2005,
Zurich,Switzerlan
Nuclear factor erythroid 2-related factor 2 activation might mitigate clinical symptoms in Friedreich’s ataxia: clues of an “out-brain origin” of the disease from a family study
Friedreich’s ataxia (FRDA) is the most frequent autosomal recessive ataxia in western countries, with a mean age of onset at 10–15 years. Patients manifest progressive cerebellar and sensory ataxia, dysarthria, lower limb pyramidal weakness, and other systemic manifestations. Previously, we described a family displaying two expanded GAA alleles not only in the proband affected by late-onset FRDA but also in the two asymptomatic family members: the mother and the younger sister. Both of them showed a significant reduction of frataxin levels, without any disease manifestation. Here, we analyzed if a protective mechanism might contribute to modulate the phenotype in this family. We particularly focused on the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), the first line of antioxidant defense in cells, and on the glutathione (GSH) system, an index of reactive oxygen species (ROS) detoxification ability. Our findings show a great reactivity of the GSH system to the frataxin deficiency, particularly in the asymptomatic mother, where the genes of GSH synthesis [glutamate–cysteine ligase (GCL)] and GSSG detoxification [GSH S-reductase (GSR)] were highly responsive. The GSR was activated even in the asymptomatic sister and in the proband, reflecting the need of buffering the GSSG increase. Furthermore, and contrasting the NRF2 expression documented in FRDA tissues, NRF2 was highly activated in the mother and in the younger sister, while it was constitutively low in the proband. This suggests that, also under frataxin depletion, the endogenous stimulation of NRF2 in asymptomatic FRDA subjects may contribute to protect against the progressive oxidative damage, helping to prevent the onset of neurological symptoms and highlighting an “out-brain origin” of the disease
Measurements and tests on FBK silicon sensors with an optimized electronic design for a CTA camera
In October 2013, the Italian Ministry approved the funding of a Research &
Development (R&D) study, within the "Progetto Premiale TElescopi CHErenkov made
in Italy (TECHE)", devoted to the development of a demonstrator for a camera
for the Cherenkov Telescope Array (CTA) consortium. The demonstrator consists
of a sensor plane based on the Silicon Photomultiplier (SiPM) technology and on
an electronics designed for signal sampling. Preliminary tests on a matrix of
sensors produced by the Fondazione Bruno Kessler (FBK-Trento, Italy) and on
electronic prototypes produced by SITAEL S.p.A. will be presented. In
particular, we used different designs of the electronics in order to optimize
the output signals in terms of tail cancellation. This is crucial for
applications where a high background is expected, as for the CTA experiment.Comment: 5 pages, 6 figures; Proceedings of the 10th Workshop on Science with
the New Generation of High-Energy Gamma-ray experiments (SciNeGHE) -
PoS(Scineghe2014)00
Perioperative Care in Colorectal Cancer Surgery before a Structured Implementation Program of the ERAS Protocol in a Regional Network. The Piemonte EASY-NET Project
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