1,296 research outputs found
Performance of the PADME calorimeter prototype at the DANE BTF
The PADME experiment at the DANE Beam-Test Facility (BTF) aims at
searching for invisible decays of the dark photon by measuring the final state
missing mass in the process , with undetected. The
measurement requires the determination of the 4-momentum of the recoil photon,
performed using a homogeneous, highly segmented BGO crystals calorimeter. We
report the results of the test of a 55 crystals prototype performed
with an electron beam at the BTF in July 2016
Effects of plasma transfusion on hepcidin production in human congenital hypotransferrinemia
Hepcidin is the key regulator of systemic iron homeostasis. We describe the modulation of hepcidin production induced by plasma transfusions in a patient with congenital hypotransferrinemia that offers a unique model in which to study the mechanism of hepcidin regulation by iron and erythropoiesis. Urinary hepcidin increased from zero at baseline, when hemoglobin and serum transferrin was low, to a maximum of 98 ng/mg creatinine on day 60, and subsequently decreased. Time-course of urinary hepcidin and serum transferrin concentration suggests that hepcidin production is regulated by the combination of marrow iron requirements and iron supply by transferrin
Screening of respiratory pathogens by Respiratory Multi Well System (MWS) r-gene™ assay in hospitalized patients
Novel respiratory viruses have been identified as possible agents of upper and lower respiratory tract infections. Multiplex real-time PCRs have been developed to identify clinically relevant respiratory pathogens. In this study, 178 respiratory samples already screened for influenza virus types A and B by Flu A/B ASR real-time PCR kit were retrospectively analyzed with the Respiratory Multi Well System (MWS) r-gene™ real-time PCR kit which detects a wide spectrum of respiratory pathogens. The goal was to demonstrate the importance of a wide spectrum screening compared to a single diagnostic request. The Flu A/B ASR kit detected influenza B virus in 1.7% of the samples (3/178) and no influenza A virus. The MWS r-gene™ kit detected influenza virus in 6.7% (12/178) of samples (0.6% influenza A, and 6.2% influenza B), while the overall detection rate for respiratory pathogens was 54% (96/178). Co-infections were detected in 8/178 (4.5%) samples. Adenovirus was the infectious agent detected most frequently, followed by respiratory syncytial virus. The risk of being infected by respiratory syncytial virus is almost threefold higher in patients older than 65 years compared to the younger age group (OR:2.7, 95% CI: 1.2-6.2). Wide spectrum screening of respiratory pathogens by real-time PCR is an effective means of detecting clinically relevant viral pathogens
Development of a Li2MoO4 scintillating bolometer for low background physics
We present the performance of a 33 g Li2MoO4 crystal working as a
scintillating bolometer. The crystal was tested for more than 400 h in a
dilution refrigerator installed in the underground laboratory of Laboratori
Nazionali del Gran Sasso (Italy). This compound shows promising features in the
frame of neutron detection, dark matter search (solar axions) and neutrinoless
double-beta decay physics. Low temperature scintillating properties were
investigated by means of different alpha, beta/gamma and neutron sources, and
for the first time the Light Yield for different types of interacting particle
is estimated. The detector shows great ability of tagging fast neutron
interactions and high intrinsic radiopurity levels (< 90 \muBq/kg for 238-U and
< 110 \muBq/kg for 232-Th).Comment: revised versio
Characterization and Performance of PADME's Cherenkov-Based Small-Angle Calorimeter
The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in
Italy, will search for invisible decays of the hypothetical dark photon via the
process , where the escapes detection. The
dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We
report here on measurement and simulation studies of the performance of the
Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting
2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of
less than 200 ps, which is satisfied by the choice of PbF crystals and the
newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a
timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns)
and a single-crystal energy resolution of 5.7%/ with light yield of
2.07 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test
Facility of LNF. We also propose the investigation of a two-PMT solution
coupled to a single PbF crystal for higher-energy applications, which has
potentially attractive features.Comment: 12 pages, 19 figures. v2: added section on radiation damage studie
Prognostic significance of tyrosinase expression in sentinel lymph node biopsy for ultra-thin, thin, and thick melanomas
Abstract. – BACKGROUND: Investigate if the tyrosinase mRNA expression may be predictive of the outcome on ultra-thin, thin, and thick melanoma patients.
AIM: In our study, we sought to correlate tyrosinase mRNA expression to the outcome in a group of 71 patients with thick, thin and ultra-thin melanomas.
MATERIALS AND METHODS: 71 patients with melanomas underwent a SLNB (sentinel lymph node biopsy) at the “Sapienza” University of Rome. Among these, 38 patients had thin melanomas, while the other 33 patients had thick melanomas. In every patient’s sample histology, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) was completed. We then correlated tyrosinase mRNA expression to the statistical analysis of the outcome of patients.
RESULTS: Positivity of histology was found in one patient (1.4%), immunohistochemistry in five patients (7%), and tyrosinase in 52/71 (73.2%). Thickness and tyrosinase positivity were predictive for disease progression (p < 0.05). The median follow-up was 58.24 months. There were recurrences and/or deaths in both groups of patients.
CONCLUSIONS: Nodal metastasis in melanoma is uncommon, especially in patients with thin melanomas. In this study, histology and immunohistochemistry were found to be non predictive
for the risk of nodal metastases, while instead, tyrosinase m-RNA expression appeared to play a role in highlighting those patients with a risk of disease progression. Moreover, no differences
among the thin melanoma groups of patients (0.30-0.75 mm and 0.76-1.00 mm) were observed
Grains of truth or transparent blindfolds?:A review of current debates in archaeological phytolith analysis
The SNARE VAMP7 Regulates Exocytic Trafficking of Interleukin-12 in Dendritic Cells
Interleukin-12 (IL-12), produced by dendritic cells in response to activation, is central to pathogen eradication and tumor rejection. The trafficking pathways controlling spatial distribution and intracellular transport of IL-12 vesicles to the cell surface are still unknown. Here, we show that intracellular IL-12 localizes in late endocytic vesicles marked by the SNARE VAMP7. Dendritic cells (DCs) from VAMP7-deficient mice are partially impaired in the multidirectional release of IL-12. Upon encounter with antigen-specific T cells, IL-12-containing vesicles rapidly redistribute at the immune synapse and release IL-12 in a process entirely dependent on VAMP7 expression. Consistently, acquisition of effector functions is reduced in T cells stimulated by VAMP7-null DCs. These results provide insights into IL-12 intracellular trafficking pathways and show that VAMP7-mediated release of IL-12 at the immune synapse is a mechanism to transmit innate signals to T cells
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Pre-Columbian land use in the ring-ditch region of the Bolivian Amazon
The nature and extent of pre-Columbian (pre-1492 AD) human impact in Amazonia is a contentious issue. The Bolivian Amazon has yielded some of the most impressive evidence for large and complex pre-Columbian societies in the Amazon basin, yet there remains relatively little data concerning the land use of these societies over time. Palaeoecology, when integrated with archaeological
data, has the potential to fill these gaps in our knowledge. We present a 6,000-year record of anthropogenic burning, agriculture and vegetation change, from an oxbow lake located adjacent to a pre-Columbian ring-ditch in north-east Bolivia (13°15’44” S, 63°42’37” W). Human occupation around the lake site is inferred from pollen and phytoliths of maize (Zea mays L.) and macroscopic charcoal evidence of anthropogenic burning. First occupation around the lake was radiocarbon dated to ~2500 years BP. The persistence of maize in the record from ~1850 BP suggests that it was an important crop grown in the ringditch region in pre-Columbian times, and abundant macroscopic charcoal suggests that pre-Columbian land management entailed more extensive burning of the landscape than the slash-and-burn agriculture practised around the site today. The site was occupied continuously until near-modern times, although there is evidence for a decline in agricultural intensity or change in land use strategy, and possible population decline, from ~600-500 BP. The long and continuous occupation, which predates the establishment of rainforest in the region, suggests that pre-Columbian land use may have had a significant
influence on ecosystem development at this site over the last ~2000 years
Mesh adaptation strategies using wall functions and low-Reynolds models
International audienceThe scope of this paper is to determine an optimal mesh adaptation strategy to compute turbulent flows in presence of solid bodies using RANS models. To this end we propose to use additionally model specific wall functions when the low-Reynolds turbulence model is not sufficiently resolved. Such wall functions degenerate to the low-Reynolds turbulence model they mimic when the mesh size tends to 0. This significantly improves solutions on coarse initial grids and fasten computations toward the final solution
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