399 research outputs found
A simplified sars-cov-2 pseudovirus neutralization assay
COVID-19 is an ongoing pandemic caused by the highly infectious coronavirus SARS-CoV-2 that is engaging worldwide scientific research to find a timely and effective eradication strategy. Great efforts have been put into anti-COVID-19 vaccine generation in an effort to protect the world population and block SARS-CoV-2 spread. To validate the protective efficacy of the vaccination campaign and effectively control the pandemic, it is necessary to quantify the induction of neutralizing antibodies by vaccination, as they have been established to be a correlate of protection. In this work, a SARS-CoV-2 pseudovirus neutralization assay, based on a replication-incompetent lentivirus expressing an adapted form of CoV-2 S protein and an ACE2/TMPRSS2 stably expressing cell line, has been minimized in terms of protocol steps without loss of accuracy. The goal of the present simplified neutralization system is to improve SARS-CoV-2 vaccination campaign by means of an easy and accessible approach to be performed in any medical laboratory, maintaining the sensitivity and quantitative reliability of classical serum neutralization assays. Further, this assay can be easily adapted to different coronavirus variants by simply modifying the pseudotyping vector
Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter
This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered
Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up
Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated
Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV
A search for new physics is presented based on an event signature of at least
three jets accompanied by large missing transverse momentum, using a data
sample corresponding to an integrated luminosity of 36 inverse picobarns
collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector
at the LHC. No excess of events is observed above the expected standard model
backgrounds, which are all estimated from the data. Exclusion limits are
presented for the constrained minimal supersymmetric extension of the standard
model. Cross section limits are also presented using simplified models with new
particles decaying to an undetected particle and one or two jets
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
Performance and Operation of the CMS Electromagnetic Calorimeter
The operation and general performance of the CMS electromagnetic calorimeter
using cosmic-ray muons are described. These muons were recorded after the
closure of the CMS detector in late 2008. The calorimeter is made of lead
tungstate crystals and the overall status of the 75848 channels corresponding
to the barrel and endcap detectors is reported. The stability of crucial
operational parameters, such as high voltage, temperature and electronic noise,
is summarised and the performance of the light monitoring system is presented
IL21R expressing CD14+CD16+ monocytes expand in multiple myeloma patients leading to increased osteoclasts
Bone marrow monocytes are primarily committed to osteoclast formation. It is, however, unknown whether potential primary alterations are specifically present in bone marrow monocytes of multiple myeloma patients, smoldering myeloma or monoclonal gammopathy of uncertain significance. Herein, we analyzed the immunophenotypic and transcriptional profiles of bone marrow CD14+ monocytes in a cohort of patients with different types of monoclonal gammopathies to identify alterations involved in myeloma-enhanced osteoclastogenesis. A higher number of bone marrow CD14+CD16+ cells was found in patients with active myeloma as compared to those with smoldering myeloma and monoclonal gammopathy of uncertain significance. Interestingly, sorted bone marrow CD14+CD16+ cells from myeloma patients were more pro-osteoclastogenic than CD14+CD16- cells in cultures ex vivo. Moreover, transcriptional analysis demonstrated that bone marrow multiple myeloma (but neither monoclonal gammopathy of uncertain significance nor smoldering myeloma) CD14+ cells significantly upregulated genes involved in osteoclast formation, including IL21R. IL21R mRNA over-expression by bone marrow CD14+ cells was independent from the presence of IL-21. Consistently, IL-21 production by T cells as well as IL-21 bone marrow levels were not significantly different among monoclonal gammopathies. Thereafter, we showed that IL21R over-expression in CD14+ cells increased osteoclast formation. Consistently, IL-21R signaling inhibition by Janex 1 suppressed osteoclast differentiation from bone marrow CD14+ cells of myeloma patients. Our results indicated that multiple myeloma patients showed distinct bone marrow monocyte features compared to those with indolent monoclonal gammopathies, supporting the role of IL21R over-expression by bone marrow CD14+ cells in enhanced osteoclast formation
Search for three-jet resonances in pp Collisions at âs=7ââTeV
This article is published Open Access at sciencedirect.com. It is distributed under the terms of the Creative Commons Attribution License 3.0.-- et al.Results are reported from a search for the production of three-jet resonances in pp collisions at a center-of-mass energy âs=7ââTeV. The study uses the data sample collected by the CMS experiment at the LHC in 2011, corresponding to an integrated luminosity of 5.0fb -1. Events with high jet multiplicity and a large scalar sum of jet transverse momenta are analyzed for the presence of resonances in the three-jet invariant mass spectrum. No evidence for a narrow resonance is found in the data, and limits are set on the cross section for gluino pair production in an R-parity-violating supersymmetry model, for gluino masses greater than 280 GeV. Assuming a branching fraction for gluino decay into three jets of 100%, gluino masses below 460 GeV are excluded at 95% confidence level. These results significantly extend the range of previous limits. Š 2012 CERN.European Commission; Federal Ministry of Science, Research and Economy (Austria); ); Agency for Innovation by Science and Technology (Belgium); Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (Brasil); Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (Brasil); Fundação Carlos Chagas Filho de Amparo Ă Pesquisa do Estado do Rio de Janeiro; Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo; Ministry of Science and Technology of the People's Republic of China; National Natural Science Foundation of China; Colciencias (Colombia); Ministry of Science, Education and Sports of the Republic of Croatia; Research Promotion Foundation (Cyprus); Centre National de la Recherche Scientifique (France); Bundesministerium fĂźr Bildung und Forschung (Deutschland); Deutsche Forschungsgemeinschaft; General Secretariat of Research and Technology (Greece); Helsinki Institute of Physics; National Office for Research and Technology (Hungary); Institute for Research in Fundamental Sciences (Iran); Science Foundation Ireland; Istituto Nazionale di Fisica Nucleare (Italia); Compagnia di San Paolo (Italia); National Research Foundation of Korea; Centro de InvestigaciĂłn y de Estudios Avanzados del Instituto PolitĂŠcnico Nacional (MĂŠxico); Consejo Nacional de Ciencia y TecnologĂa (MĂŠxico); SecretarĂa de EducaciĂłn PĂşblica (MĂŠxico); Universidad AutĂłnoma de San Luis PotosĂ; Ministry of Science and Innovation (New Zealand); Pakistan Atomic Energy Commission; National Science Center (Poland); Fundação para a CiĂŞncia e a Tecnologia (Portugal); Joint Institute for Nuclear Research (Russia); Russian Foundation for Basic Research; Ministry of Education, Science and Technological Development (Serbia); Ministerio de Ciencia e InnovaciĂłn (EspaĂąa); Swiss National Science Foundation.Peer Reviewe
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