Magnetic resonance imaging in the prenatal diagnosis of neural tube defects

OBJECTIVE: To assess the role of magnetic resonance imaging (MRI) in the prenatal diagnosis of neural tube defects (NTDs). BACKGROUND: NTDs comprise a heterogeneous group of congenital anomalies that derive from the failure of the neural tube to close. Advances in ultrasonography and MRI have considerably improved the diagnosis and treatment of NTDs both before and after birth. Ultrasonography is the first technique in the morphological study of the fetus, and it often makes it possible to detect or suspect NTDs. Fetal MRI is a complementary technique that makes it possible to clear up uncertain ultrasonographic findings and to detect associated anomalies that might go undetected at ultrasonography. The progressive incorporation of intrauterine treatments makes an accurate diagnosis of NTDs essential to ensure optimal perinatal management. The ability of fetal MRI to detect complex anomalies that affect different organs has been widely reported, and it can be undertaken whenever NTDs are suspected. CONCLUSION: We describe the normal appearance of fetal neural tube on MRI, and we discuss the most common anomalies involving the structures and the role of fetal MRI in their assessment. KEY POINTS: • To learn about the normal anatomy of the neural tube on MRI • To recognise the MR appearance of neural tube defects • To understand the value of MRI in assessing NTD

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Real-Time PCR Improves Helicobacter pylori Detection in Patients with Peptic Ulcer Bleeding

Background and aims: Histological and rapid urease tests to detect H. pylori in biopsy specimens obtained during peptic ulcer bleeding episodes (PUB) often produce false-negative results. We aimed to examine whether immunohistochemistry and real-time PCR can improve the sensitivity of these biopsies. Patients and Methods: We selected 52 histology-negative formalin-fixed paraffin-embedded biopsy specimens obtained during PUB episodes. Additional tests showed 10 were true negatives and 42 were false negatives. We also selected 17 histology-positive biopsy specimens obtained during PUB to use as controls. We performed immunohistochemistry staining and real-time PCR for 16S rRNA, ureA, and 23S rRNA for H. pylori genes on all specimens. Results: All controls were positive for H. pylori on all PCR assays and immunohistochemical staining. Regarding the 52 initially negative biopsies, all PCR tests were significantly more sensitive than immunohistochemical staining (p<0.01). Sensitivity and specificity were 55% and 80% for 16S rRNA PCR, 43% and 90% for ureA PCR, 41% and 80% for 23S rRNA PCR, and 7% and 100% for immunohistochemical staining, respectively. Combined analysis of PCR assays for two genes were significantly more sensitive than ureA or 23S rRNA PCR tests alone (p<0.05) and marginally better than 16S rRNA PCR alone. The best combination was 16S rRNA+ureA, with a sensitivity of 64% and a specificity of 80%. Conclusions: Real-time PCR improves the detection of H. pylori infection in histology-negative formalin-fixed paraffin-embedded biopsy samples obtained during PUB episodes. The low reported prevalence of H. pylori in PUB may be due to the failure of conventional tests to detect infection

Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for pp collisions at √s=5.02 and 13 TeV and p+Pb collisions at √sNN=5.02 TeV with the ATLAS detector

ATLAS measurements of two-particle correlations are presented for √s=5.02 and 13 TeV ppcollisions and for √sNN=5.02 TeV p+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δϕ, and pseudorapidity separation Δη, using charged particles detected within the pseudorapidity interval |η|2, is studied using a template fitting procedure to remove a “back-to-back” contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos (2Δϕ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos (3Δϕ) and cos (4Δϕ) modulation. The Fourier coefficients vn, n associated with the cos (nΔϕ) modulation of the correlation functions for n=2–4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos (nϕ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2–4. The integrated luminosities used in this analysis are, 64nb−1 for the √s=13 TeV pp data, 170 nb−1 for the √ s = 5.02 TeV pp data, and 28 nb−1 for the √sNN = 5.02 TeV p+Pb data

Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in pp collisions at √s=13 TeV with the ATLAS detector

A search for new particles decaying into a pair of top quarks is performed using proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of √s=13  TeV corresponding to an integrated luminosity of 36.1  fb−1. Events consistent with top-quark pair production and the fully hadronic decay mode of the top quarks are selected by requiring multiple high transverse momentum jets including those containing b-hadrons. Two analysis techniques, exploiting dedicated top-quark pair reconstruction in different kinematic regimes, are used to optimize the search sensitivity to new hypothetical particles over a wide mass range. The invariant mass distribution of the two reconstructed top-quark candidates is examined for resonant production of new particles with various spins and decay widths. No significant deviation from the Standard Model prediction is observed and limits are set on the production cross-section times branching fraction for new hypothetical Z′ bosons, dark-matter mediators, Kaluza-Klein gravitons and Kaluza-Klein gluons. By comparing with the predicted production cross sections, the Z′ boson in the topcolor-assisted-technicolor model is excluded for masses up to 3.1–3.6 TeV, the dark-matter mediators in a simplified framework are excluded in the mass ranges from 0.8 to 0.9 TeV and from 2.0 to 2.2 TeV, and the Kaluza-Klein gluon is excluded for masses up to 3.4 TeV, depending on the decay widths of the particles

Search for Higgs bosons produced via vector-boson fusion and decaying into bottom quark pairs in √s =13 TeV pp collisions with the ATLAS detector

A search for the bb ¯ decay of the Standard Model Higgs boson produced through vector-boson fusion is presented. Three mutually exclusive channels are considered: two all-hadronic channels and a photon-associated channel. Results are reported from the analysis of up to 30.6 fb −1 of pp data at s √ =13 TeV collected with the ATLAS detector at the LHC. The measured signal strength relative to the Standard Model prediction from the combined analysis is 2.5 +1.4 −1.3 for inclusive Higgs boson production and 3.0 +1.7 −1.6 for vector-boson fusion production only

Search for heavy charged long-lived particles in the ATLAS detector in 36.1 fb− 1 of proton-proton collision data at √s =13 TeV

A search for heavy charged long-lived particles is performed using a data sample of 36.1 fb−1 of proton-proton collisions at √s =13 TeV collected by the ATLAS experiment at the Large Hadron Collider. The search is based on observables related to ionization energy loss and time of flight, which are sensitive to the velocity of heavy charged particles traveling significantly slower than the speed of light. Multiple search strategies for a wide range of lifetimes, corresponding to path lengths of a few meters, are defined as model independently as possible, by referencing several representative physics cases that yield long-lived particles within supersymmetric models, such as gluinos/squarks (R-hadrons), charginos and staus. No significant deviations from the expected Standard Model background are observed. Upper limits at 95% confidence level are provided on the production cross sections of long-lived R-hadrons as well as directly pair produced staus and charginos. These results translate into lower limits on the masses of long-lived gluino, sbottom and stop R-hadrons, as well as staus and charginos of 2000, 1250, 1340, 430, and 1090 GeV, respectively