Measurement of quarkonium production in proton-lead and proton-proton collisions at 5.02 TeV with the ATLAS detector

The modification of the production of J / ψ , ψ ( 2 S ) , and Υ ( n S ) ( n = 1 , 2 , 3 ) in p+Pb collisions with respect to their production in pp collisions has been studied. The p+Pb and pp datasets used in this paper correspond to integrated luminosities of 28 nb - 1 and 25 pb - 1 respectively, collected in 2013 and 2015 by the ATLAS detector at the LHC, both at a centre-of-mass energy per nucleon pair of 5.02 TeV. The quarkonium states are reconstructed in the dimuon decay channel. The yields of J / ψ and ψ ( 2 S ) are separated into prompt and non-prompt sources. The measured quarkonium differential cross sections are presented as a function of rapidity and transverse momentum, as is the nuclear modification factor, R p Pb for J / ψ and Υ ( n S ) . No significant modification of the J / ψ production is observed while Υ ( n S ) production is found to be suppressed at low transverse momentum in p+Pb collisions relative to pp collisions. The production of excited charmonium and bottomonium states is found to be suppressed relative to that of the ground states in central p+Pb collisions.

Measurement of τ polarisation in Z / γ ∗ → τ τ decays in proton-proton collisions at s = 8 TeV with the ATLAS detector

This paper presents a measurement of the polarisation of τ leptons produced in Z / γ ∗ → τ τ decays which is performed with a dataset of proton-proton collisions ats = 8 TeV, corresponding to an integrated luminosity of 20.2 fb- 1 recorded with the ATLAS detector at the LHC in 2012. The Z / γ ∗ → τ τ decays are reconstructed from a hadronically decaying τ lepton with a single charged particle in the final state, accompanied by a τ lepton that decays leptonically. The τ polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic τ decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The τ polarisation extracted over the full phase space within the Z / γ ∗ mass range of 66 < m Z / γ ∗ < 116 GeV is found to beP τ = - 0.14 ± 0.02 ( stat ) ± 0.04 ( syst ) . It is in agreement with the Standard Model prediction ofP τ = - 0.1517 ± 0.0019 , which is obtained from the ALPGEN event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA τ decay library.

Search for the direct production of charginos and neutralinos in final states with tau leptons in s = 13 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 36.1 fb- 1 , recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. No significant deviation from the expected Standard Model background is observed. Limits are derived in scenarios of pair production and of and production in simplified models where the neutralinos and charginos decay solely via intermediate left-handed staus and tau sneutrinos, and the mass of theτ ~ L state is set to be halfway between the masses of the and the . Chargino masses up to 630 GeV are excluded at 95% confidence level in the scenario of direct production of for a massless . Common and masses up to 760 GeV are excluded in the case of production of and assuming a massless . Exclusion limits for additional benchmark scenarios with large and small mass-splitting between the and the are also studied by varying theτ ~ L mass between the masses of the and the .

Measurement of longitudinal flow decorrelations in Pb+Pb collisions at s NN = 2.76 and 5.02 TeV with the ATLAS detector

Measurements of longitudinal flow correlations are presented for charged particles in the pseudorapidity range | η | < 2.4 using 7 and 470 μ b - 1 of Pb+Pb collisions ats NN = 2.76 and 5.02 TeV, respectively, recorded by the ATLAS detector at the LHC. It is found that the correlation between the harmonic flow coefficients v n measured in two separated η intervals does not factorise into the product of single-particle coefficients, and this breaking of factorisation, or flow decorrelation, increases linearly with the η separation between the intervals. The flow decorrelation is stronger at 2.76 TeV than at 5.02 TeV. Higher-order moments of the correlations are also measured, and the corresponding linear coefficients for the k th -moment of the v n are found to be proportional to k for v 3 , but not for v 2 . The decorrelation effect is separated into contributions from the magnitude of v n and the event-plane orientation, each as a function of η . These two contributions are found to be comparable. The longitudinal flow correlations are also measured between v n of different order in n. The decorrelations of v 2 and v 3 are found to be independent of each other, while the decorrelations of v 4 and v 5 are found to be driven by the nonlinear contribution from v 2 2 andv 2 v 3 , respectively.

Direct top-quark decay width measurement in the t t ¯ lepton+jets channel at s = 8 TeV with the ATLAS experiment

This paper presents a direct measurement of the decay width of the top quark using t t ¯ events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb- 1 . The decay width of the top quark is measured using a template fit to distributions of kinematic observables associated with the hadronically and semileptonically decaying top quarks. The result,Γ t = 1.76 ± 0.33 ( stat. ) - 0.68 + 0.79 ( syst. ) GeV for a top-quark mass of 172.5 GeV, is consistent with the prediction of the Standard Model.

Abstract P1-09-08: BCL2L1 (BCL-XL) expression and MYC super-enhancer positivity predict sensitivity to the covalent CDK7 inhibitor SY-1365 in triple negative breast cancer (TNBC) cell lines

Effective therapies for TNBC remain elusive. As such, TNBCs are associated with a high risk of relapse and short progression free- and overall-survival. Recent studies showed that TNBC cells are highly dependent on the transcriptional regulator CDK7, and suggest that the mitochondrial apoptosis pathway is important in mediating cell survival in CDK7-dependent cells. Further, TNBC has been shown to have a distinct epigenetic and transcriptional program, with super-enhancers (SE) mediating the expression of key oncogenic drivers such as MYC. SY-1365, a covalent and selective inhibitor of CDK7, was developed to exploit dysregulated programs thought to drive SE-mediated transcriptional-dependencies in TNBC and other cancers. To identify potential biomarkers predictive of sensitivity to SY-1365, we evaluated SY-1365 inhibitory activity in a large panel of human tumor cell lines, including TNBC lines, and correlated sensitivity with RNA expression and epigenetic profiles.

SY-1365 dose-response curves were measured using the ATP-lite assay in a panel of 406 human tumor cell lines, including 19 TNBC cell lines. Clustering of growth-rate adjusted dose response curves of cell-lines treated with SY-1365 allowed the classification of cell-lines into low and high response groups. An unbiased genome wide approach was used to compare response classification to RNA expression data across all cell lines to identify gene expression markers predictive of sensitivity to SY-1365. Furthermore, a hypothesis driven approach was followed to interrogate whether the MYC SE predicted sensitivity to SY-1365.

Twenty-five genes were differentially expressed between SY-1365-sensitive and -insensitive tumor lines (FDR&lt;0.05). Lower expression of BCL2L1, which encodes the mitochondrial apoptosis regulator BCL-XL, was identified as the most predictive expression biomarker of sensitivity across all profiled cell lines, strongly separating the two classes of sensitivity (Accuracy=70%, FDR&lt;0.005). Further, this predictive power of lower BCL2L1 expression was maintained in an analysis restricted to the subset of TNBC cell-lines (Accuracy=73%).

Expanding beyond expression analysis, we also found that the strength of the MYC SE (as defined by H3K27Ac) was predictive of response to SY-1365 in TNBC (Accuracy=86%, FDR&lt;0.05).

In this study, we show for the first time that SY-1365 induced differential responses across a large panel of human tumor cell lines derived from multiple indications. We also show that in this panel of cell lines the response could be predicted in an “indication agnostic” manner by the level of expression of BCL2L1. Finally, in line with prior reports, in TNBC cell lines, MYC SE was significantly associated with sensitivity to SY-1365. These observations have generated strong hypotheses for selection strategies aimed at identifying patients with tumors particularly sensitive to CDK7 inhibition with SY-1365, and warrant further investigation with respect to predictive biomarkers of response in patients. SY-1365 is currently being assessed in a phase 1 trial in adult patients with advanced solid tumors, including a planned expansion cohort enriching for patients with TNBC (NCT03134638).

Citation Format: Rajagopal N, Hodgson G, Hu S, McKeown M, Bush A, Fritz C, Orlando D, Olson E, di Tomaso E. BCL2L1 (BCL-XL) expression and MYC super-enhancer positivity predict sensitivity to the covalent CDK7 inhibitor SY-1365 in triple negative breast cancer (TNBC) cell lines [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-09-08.

The localization and function of p38α mitogen-activated protein kinase in rat oocytes

P38α mitogen-activated protein kinase (MAPK), which is a member of the canonical MAPK family, is activated in response to various extracellular stresses and plays a role in multiple cellular processes. In this study, we investigated the expression, subcellular localization and functional roles of p38α MAPK during the meiotic maturation of rat oocytes. We found that p38α MAPK phosphorylation (p-p38α MAPK, indicative of p38α MAPK activation) was low at the germinal vesicle (GV) stage, increased 3 hr after germinal vesicle breakdown (GVBD) and maintained its maximum at metaphase I (MI) or metaphase II (MII). The p-p38α MAPK mainly accumulated in the GV and had no obvious expression in the nucleus. From GVBD to MII, p-p38α MAPK was distributed in the cytoplasm around either the chromosomes or the spindle. We used SB203580, an inhibitor of p38α MAPK, to investigate the possible functional role of p38α MAPK during rat oocyte meiotic maturation. Treatment of GV stage oocytes with 20 μM SB203580 blocked p-p38α MAPK activity, and the spindles appeared abnormal. Additionally, the rate of GVBD after 3 hr of culture with 20 μM SB203580 (58.8%) was significantly inhibited compared with the control (82.5%, p < .05), and the polar body extrusion rate after 12 hr of culture with SB203580 was also significantly decreased compared with the control (40.1% vs 73.3%, p < .05). Taken together, these data indicate that p38α MAPK may play a vital role in rat oocyte meiotic maturation.

Measurement of the W-boson mass in pp collisions at s = 7 TeV with the ATLAS detector

A measurement of the mass of the W boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb - 1 of integrated luminosity. The selected data sample consists of 7.8 × 10 6 candidates in the W → μ ν channel and 5.9 × 10 6 candidates in the W → e ν channel. The W-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the W boson transverse mass in the electron and muon decay channels, yielding m W = 80370 ± 7 ( stat. ) ± 11 ( exp. syst. ) ± 14 ( mod. syst. ) MeV = 80370 ± 19 MeV , where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the W + and W - bosons yields m W + - m W - = - 29 ± 28  MeV.

Measurement of the W-boson mass in pp collisions at s = 7 TeV with the ATLAS detector

A measurement of the mass of the W boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb - 1 of integrated luminosity. The selected data sample consists of 7.8 × 10 6 candidates in the W → μ ν channel and 5.9 × 10 6 candidates in the W → e ν channel. The W-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the W boson transverse mass in the electron and muon decay channels, yieldingm W = 80370 ± 7 ( stat. ) ± 11 ( exp. syst. ) ± 14 ( mod. syst. ) MeV = 80370 ± 19 MeV , where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the W + and W - bosons yieldsm W + - m W - = - 29 ± 28  MeV.

Search for new phenomena in high-mass final states with a photon and a jet from pp collisions at s = 13 TeV with the ATLAS detector

A search is performed for new phenomena in events having a photon with high transverse momentum and a jet collected in 36.7 fb - 1 of proton-proton collisions at a centre-of-mass energy of s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The invariant mass distribution of the leading photon and jet is examined to look for the resonant production of new particles or the presence of new high-mass states beyond the Standard Model. No significant deviation from the background-only hypothesis is observed and cross-section limits for generic Gaussian-shaped resonances are extracted. Excited quarks hypothesized in quark compositeness models and high-mass states predicted in quantum black hole models with extra dimensions are also examined in the analysis. The observed data exclude, at 95% confidence level, the mass range below 5.3 TeV for excited quarks and 7.1 TeV (4.4 TeV) for quantum black holes in the Arkani-Hamed-Dimopoulos-Dvali (Randall-Sundrum) model with six (one) extra dimensions.

Search for heavy resonances decaying into WW in the e ν μ ν final state in pp collisions at s = 13 TeV with the ATLAS detector

A search for neutral heavy resonances is performed in the W W → e ν μ ν decay channel using pp collision data corresponding to an integrated luminosity of 36.1 fb - 1 , collected at a centre-of-mass energy of 13TeV by the ATLAS detector at the Large Hadron Collider. No evidence of such heavy resonances is found. In the search for production via the quark-antiquark annihilation or gluon-gluon fusion process, upper limits onσ X × B ( X → W W ) as a function of the resonance mass are obtained in the mass range between 200GeV and up to 5TeV for various benchmark models: a Higgs-like scalar in different width scenarios, a two-Higgs-doublet model, a heavy vector triplet model, and a warped extra dimensions model. In the vector-boson fusion process, constraints are also obtained on these resonances, as well as on a Higgs boson in the Georgi-Machacek model and a heavy tensor particle coupling only to gauge bosons.

Search for dark matter produced in association with bottom or top quarks in s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive dark-matter particles produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and missing transverse momentum are considered. The analysis uses 36.1 fb - 1 of proton-proton collision data recorded by the ATLAS experiment ats = 13  TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are interpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour-neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross-section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour-charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV , mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements.

[Applied research of "quadri-low" combined with automatic tube current modulation and iterative model reconstruction technology in head and neck CT angiography]

Objective: To investigate the feasibility of low tube voltage, low contrast medium concentration, injection rate and volume (quadri-low) combined with automatic tube current modulation (ATCM) and iterative model reconstruction (IMR) technology in head and neck CT angiography (CTA). Methods: A total of 70 patients whose body mass index (BMI)<25 kg/m(2) underwent head and neck CTA and digital subtraction angiography (DSA) from January to July 2017 were enrolled in this prospective study. According to random number table, patients were divided into two groups: group A (n=35) was scanned according to the protocol of 120 kV, 150 mAs, 50 ml and 5 ml/s iopromide (370 mg/ml) and filtered back projection (FBP) reconstruction; group B (n=35) was scanned with 80 kV, ATCM with mean tube current of 100 mAs, 30 ml and 3 ml/s iohexol (300 mg/ml) and IMR; the other parameters kept consistent between the two groups. The maximum transverse neck diameter at the level of the hyoid bone, artery CT value and image noise were measured, signal to noise ratio (SNR), contrast to noise ratio (CNR) and figure of merit (FOM) were calculated, and the image quality was evaluated subjectively and compared with those reconstructed by DSA. Scan length, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded, and the effective dose (ED) was calculated. The chi-square and independent-sample t tests were used to compare the inter-group differences in these aforementioned data. Resutls: No significant difference was found in general information between the two groups. No significant difference existed in artery CT value, image noise, SNR and CNR between the two groups (t=-1.170-1.365, all P>0.05); however, the FOM of group B (74±40) was significantly higher than that in group A (12±4) (Z=-7.195, P=0.000). The image quality of the two groups met the requirement of clinical diagnosis[(4.1±0.7) vs (4.2±0.8) points, Z=-0.592, P>0.05], no significant difference was found in subjective evaluation and diagnostic efficacy. The CTDIvol, DLP and ED in group B were all significantly lower than those in group A (Z=-7.728, -7.202, -7.206, all P<0.05). The iodine load and iodine delivery rate (IDR) of group B was lower than that of group A (18.5 g vs 9.0 g, 1.85 mg/s vs 0.90 mg/s), and they were reduced for 51.4% in group B. Conclusions: For patients of BMI <25 kg/m(2,) low tube voltage, low contrast medium concentration, injection rate and volume combined with ATCM and IMR technology can significantly decrease radiation dose, iodine load and IDR while maintain the image quality in head and neck CTA examination.

Search for direct top squark pair production in final states with two leptons in s = 13 TeV pp collisions with the ATLAS detector

The results of a search for direct pair production of top squarks in events with two opposite-charge leptons (electrons or muons) are reported, using 36.1 fb - 1 of integrated luminosity from proton-proton collisions ats = 13 TeV collected by the ATLAS detector at the Large Hadron Collider. To cover a range of mass differences between the top squark t ~ and lighter supersymmetric particles, four possible decay modes of the top squark are targeted with dedicated selections: the decayt ~ → b χ ~ 1 ± into a b-quark and the lightest chargino withχ ~ 1 ± → W χ ~ 1 0 , the decayt ~ → t χ ~ 1 0 into an on-shell top quark and the lightest neutralino, the three-body decayt ~ → b W χ ~ 1 0 and the four-body decayt ~ → b ℓ ν χ ~ 1 0 . No significant excess of events is observed above the Standard Model background for any selection, and limits on top squarks are set as a function of the t ~ andχ ~ 1 0 masses. The results exclude at 95% confidence level t ~ masses up to about 720 GeV, extending the exclusion region of supersymmetric parameter space covered by previous searches.

Determination of the strong coupling constant α s from transverse energy-energy correlations in multijet events at s = 8 TeV using the ATLAS detector

Measurements of transverse energy-energy correlations and their associated asymmetries in multi-jet events using the ATLAS detector at the LHC are presented. The data used correspond tos = 8 TeV proton-proton collisions with an integrated luminosity of 20.2fb - 1 . The results are presented in bins of the scalar sum of the transverse momenta of the two leading jets, unfolded to the particle level and compared to the predictions from Monte Carlo simulations. A comparison with next-to-leading-order perturbative QCD is also performed, showing excellent agreement within the uncertainties. From this comparison, the value of the strong coupling constant is extracted for different energy regimes, thus testing the running ofα s ( μ ) predicted in QCD up to scales over 1 TeV . A global fit to the transverse energy-energy correlation distributions yieldsα s ( m Z ) = 0.1162 ± 0.0011 (exp.) - 0.0070 + 0.0084 (theo.) , while a global fit to the asymmetry distributions yields a value ofα s ( m Z ) = 0.1196 ± 0.0013 (exp.) - 0.0045 + 0.0075 (theo.) .

Measurement of lepton differential distributions and the top quark mass in t t ¯ production in pp collisions at s = 8 TeV with the ATLAS detector

This paper presents single lepton and dilepton kinematic distributions measured in dileptonic t t ¯ events produced in 20.2 fb - 1 ofs = 8  TeV pp collisions recorded by the ATLAS experiment at the LHC. Both absolute and normalised differential cross-sections are measured, using events with an opposite-charge e μ pair and one or two b-tagged jets. The cross-sections are measured in a fiducial region corresponding to the detector acceptance for leptons, and are compared to the predictions from a variety of Monte Carlo event generators, as well as fixed-order QCD calculations, exploring the sensitivity of the cross-sections to the gluon parton distribution function. Some of the distributions are also sensitive to the top quark pole mass; a combined fit of NLO fixed-order predictions to all the measured distributions yields a top quark mass value ofm t pole = 173.2 ± 0.9 ± 0.8 ± 1.2  GeV, where the three uncertainties arise from data statistics, experimental systematics, and theoretical sources.

Experimental study of peripheral-blood pro-surfactant protein B for screening non-small cell lung cancer

Purpose:

To evaluate the possibility of using peripheral-blood presurfactant protein B (Pro-SFTPB) for screening non-small cell lung cancer (NSCLC).

Methods:

A total of 873 healthy volunteers and 165 lung cancer patients hospitalized in the Fifth People's Hospital of Dalian were tested Pro-SFTPB once every half year from January 2014 to September 2015. The healthy volunteers were also conducted spiral computed tomography (CT) examination once every year. The data were then com-pared and statistically analyzed.

Results:

The positive expression rate of Pro-SFTPB in NSCLC was significantly higher than that in healthy volunteers, and significantly higher in lung adenocarcinoma than in squamous cell carcinoma; additionally, the expression rate was increased with the in-crease of smoking index, and the intergroup differences showed statistical signifi-cance (p≤0.05). The positive rate of newly diagnosed lung cancer was 29.55%, higher than healthy volunteers (22.34%), but there was no significant difference (p>0.05).

Conclusion:

Pro-SFTPB is over expressed in non-small cell lung cancer, especially in lung adeno-carcinoma, but it can't be used as a clinical screening tool for lung cancer.

Measurement of detector-corrected observables sensitive to the anomalous production of events with jets and large missing transverse momentum in p p collisions at s = 13 TeV using the ATLAS detector

Observables sensitive to the anomalous production of events containing hadronic jets and missing momentum in the plane transverse to the proton beams at the Large Hadron Collider are presented. The observables are defined as a ratio of cross sections, for events containing jets and large missing transverse momentum to events containing jets and a pair of charged leptons from the decay of a Z / γ ∗ boson. This definition minimises experimental and theoretical systematic uncertainties in the measurements. This ratio is measured differentially with respect to a number of kinematic properties of the hadronic system in two phase-space regions; one inclusive single-jet region and one region sensitive to vector-boson-fusion topologies. The data are found to be in agreement with the Standard Model predictions and used to constrain a variety of theoretical models for dark-matter production, including simplified models, effective field theory models, and invisible decays of the Higgs boson. The measurements use 3.2 fb- 1 of proton-proton collision data recorded by the ATLAS experiment at a centre-of-mass energy of 13  TeV and are fully corrected for detector effects, meaning that the data can be used to constrain new-physics models beyond those shown in this paper.

Search for Heavy Higgs Bosons A/H Decaying to a Top Quark Pair in pp Collisions at sqrt[s]=8 TeV with the ATLAS Detector

A search for heavy pseudoscalar (A) and scalar (H) Higgs bosons decaying into a top quark pair (tt[over ¯]) has been performed with 20.3  fb^{-1} of proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider at a center-of-mass energy sqrt[s]=8  TeV. Interference effects between the signal process and standard model tt[over ¯] production, which are expected to distort the signal shape from a single peak to a peak-dip structure, are taken into account. No significant deviation from the standard model prediction is observed in the tt[over ¯] invariant mass spectrum in final states with an electron or muon, large missing transverse momentum, and at least four jets. The results are interpreted within the context of a type-II two-Higgs-doublet model. Exclusion limits on the signal strength are derived as a function of the mass m_{A/H} and the ratio of the vacuum expectation values of the two Higgs fields, tanβ, for m_{A/H}>500  GeV.

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to bb[over ¯] Using 36 fb^{-1} of pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

Several extensions of the standard model predict associated production of dark-matter particles with a Higgs boson. Such processes are searched for in final states with missing transverse momentum and a Higgs boson decaying to a bb[over ¯] pair with the ATLAS detector using 36.1  fb^{-1} of pp collisions at a center-of-mass energy of 13 TeV at the LHC. The observed data are in agreement with the standard model predictions and limits are placed on the associated production of dark-matter particles and a Higgs boson.

Feasibility study of iterative model reconstruction combined with low tube voltage, low iodine load, and low iodine delivery rate in craniocervical CT angiography

AIM

To investigate the feasibility of iterative model reconstruction (IMR) combined with low tube voltage, low iodine load, and low iodine deliver rate in craniocervical computed tomography angiography (CTA).

MATERIALS AND METHODS

Sixty patients were randomly divided into two groups (n=30 for each): group A: 120 kVp, 50 ml of iopromide at a flow rate of 5 ml/s; filtered back projection (FBP) reconstruction; group B: 80 kVp, 30 ml of iohexol at 4.5 ml/s; hybrid iterative reconstruction (HIR) for group B1 and IMR for group B2. CT attenuation values, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective image quality, effective dose (ED), iodine load, and iodine delivery rate (IDR) were compared.

RESULTS

CT attenuation values of the arteries were higher in groups B1 and B2 than group A. The SNR and CNR were higher, while image noise was lower, for group B2 compared with groups B1 and A. The best subjective image quality was obtained with group B2. ED, iodine load, and IDR reduction of 69.6%, 51.4%, 27%, respectively, was obtained in group B compared with group A.

CONCLUSION

IMR combined with 80 kVp and 30 ml of iohexol at a flow rate of 4.5 ml/s for craniocervical CTA can reduce ED, iodine load, and IDR, while improving image quality.

Performance of the ATLAS track reconstruction algorithms in dense environments in LHC Run 2

With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13 [Formula: see text] for Run 2, events with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking detectors sensor granularity. Basic track quantities are compared between 3.2 fb[Formula: see text] of data collected by the ATLAS experiment and simulation of proton-proton collisions producing high-transverse-momentum jets at a centre-of-mass energy of 13 [Formula: see text]. The impact of charged-particle separations and multiplicities on the track reconstruction performance is discussed. The track reconstruction efficiency in the cores of jets with transverse momenta between 200 and 1600 [Formula: see text] is quantified using a novel, data-driven, method. The method uses the energy loss, [Formula: see text], to identify pixel clusters originating from two charged particles. Of the charged particles creating these clusters, the measured fraction that fail to be reconstructed is [Formula: see text] and [Formula: see text] for jet transverse momenta of 200-400 [Formula: see text] and 1400-1600 [Formula: see text], respectively.

Mirtogenol® supplementation in association with dorzolamide-timolol or latanoprost improves the retinal microcirculation in asymptomatic patients with increased ocular pressure

OBJECTIVE

Supplementation with Mirtogenol® improves the retinal microcirculation and reduces intraocular pressure (IOP) in ocular hypertension, when administrated either alone or in association with an ophthalmic solution (latanoprost). In this study, microcirculatory parameters (perfusion of the circle of Zinn-Haller and retinal circulation) and oxidative stress were tested to assess the effects of Mirtogenol® plus traditional antihypertensive drugs in patients with elevated IOP.

PATIENTS AND METHODS

88 otherwise healthy patients with increased IOP were followed-up in a supplement registry for 12 weeks. Three groups received; (a) dorzolamide-timolol plus Mirtogenol®; (b) latanoprost drops plus Mirtogenol® or (c) latanoprost only. Oral supplementation consisted of two tablets/day of Mirtogenol® (80 mg of bilberry extract, Mirtoselect® plus 40 mg of Pycnogenol®). IOP, retinal blood flow, perfusion of the circle of Zinn-Haller, and oxidative stress were measured during the registry period.

RESULTS

The three study groups were comparable; IOP and ocular blood flow velocity at inclusion were also comparable. Over the study period the decrease in IOP and the improvements in retinal microcirculation were statistically significant for all management groups, with a marginally more evident benefit in Mirtogenol®+latanosprost-treated patients. At 12 weeks, the altered perfusion at the circle of Zinn-Haller was improved in all groups; patients using Mirtogenol® showed a better perfusional pattern compared with subjects using only latanoprost. A reduction in oxidative stress was observed in supplemented subjects at the end of the study period; no significant change was seen in non-supplemented patients. All managements were well-tolerated without side effects.

CONCLUSIONS

Supplementation with Mirtogenol®, in addition to local ophthalmic treatments, is safe and may contribute as a supplementary management to reach a normal IOP and ocular microcirculatory parameters.

Study of W W γ and W Z γ production in p p collisions at s = 8 TeV and search for anomalous quartic gauge couplings with the ATLAS experiment

This paper presents a study of W W γ and W Z γ triboson production using events from proton-proton collisions at a centre-of-mass energy ofs = 8 TeV recorded with the ATLAS detector at the LHC and corresponding to an integrated luminosity of 20.2 fb- 1 . The W W γ production cross-section is determined using a final state containing an electron, a muon, a photon, and neutrinos ( e ν μ ν γ ). Upper limits on the production cross-section of the e ν μ ν γ final state and the W W γ and W Z γ final states containing an electron or a muon, two jets, a photon, and a neutrino ( e ν j j γ or μ ν j j γ ) are also derived. The results are compared to the cross-sections predicted by the Standard Model at next-to-leading order in the strong-coupling constant. In addition, upper limits on the production cross-sections are derived in a fiducial region optimised for a search for new physics beyond the Standard Model. The results are interpreted in the context of anomalous quartic gauge couplings using an effective field theory. Confidence intervals at 95% confidence level are derived for the 14 coupling coefficients to which W W γ and W Z γ production are sensitive.

[Value of spectral CT-based quantitative analysis in differential diagnosis of liver cancer and liver abscess]

Objective: To investigate the value of spectral CT-based quantitative analysis in the differential diagnosis of liver cancer and liver abscess. Methods: A total of 70 patients with space-occupying lesions in the liver(45 with liver cancer and 25 with liver abscess)underwent spectral CT scans to obtain spectral images in the arterial phase and portal venous phase. The solid constituents of lesions and the iodine and water concentrations in necrotic or cystic parts of lesions, normal hepatic tissue, and abdominal aorta in the arterial phase and portal venous phase were measured, and the normalized iodine concentration(NIC)and lesion-to-normal hepatic tissue ratio(LNR)of iodine concentration were calculated. The two samples t-test and the receiver operating characteristic(ROC)curve analysis were performed for the quantitative indices above. Results: The patients with liver cancer had higher NIC and LNR in solid constituents in the arterial phase than those with liver abscess(NIC: 0.15±0.06 mg/ml vs 0.14±0.02 mg/ml, P > 0.05; LNR: 2.78±0.65 vs 1.45±0.88, P < 0.001). The patients with liver abscess had significantly higher NIC and LNR in solid constituents in the portal venous phase than those with liver cancer(NIC: 0.65±0.08 mg/ml vs 0.52±0.08 mg/ml, P≤0.001; LNR: 1.22±0.23 vs 0.95±0.15, P≤0.001). There were no significant differences in NIC in the arterial phase or NIC and LNR in the portal venous phase in necrotic or cystic parts of lesions between the patients with liver cancer and liver abscess(P > 0.05). The optimal quantitative value for the differential diagnosis of liver cancer and liver abscess was LNR in arterial phase, and the cut-off value of 1.53 had a sensitivity of 100% and a specificity of 92%. Conclusion: Quantitative iodine concentration analysis in spectral CT imaging has a certain value in the differential diagnosis of liver cancer and liver abscess and can improve the accuracy of diagnosis.

Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector

The rejection of forward jets originating from additional proton-proton interactions (pile-up) is crucial for a variety of physics analyses at the LHC, including Standard Model measurements and searches for physics beyond the Standard Model. The identification of such jets is challenging due to the lack of track and vertex information in the pseudorapidity range | η | > 2.5 . This paper presents a novel strategy for forward pile-up jet tagging that exploits jet shapes and topological jet correlations in pile-up interactions. Measurements of the per-jet tagging efficiency are presented using a data set of 3.2 fb- 1 of proton-proton collisions at a centre-of-mass energy of 13TeV collected with the ATLAS detector. The fraction of pile-up jets rejected in the range 2.5 < | η | < 4.5 is estimated in simulated events with an average of 22 interactions per bunch-crossing. It increases with jet transverse momentum and, for jets with transverse momentum between 20 and 50 GeV, it ranges between 49% and 67% with an efficiency of 85% for selecting hard-scatter jets. A case study is performed in Higgs boson production via the vector-boson fusion process, showing that these techniques mitigate the background growth due to additional proton-proton interactions, thus enhancing the reach for such signatures.

Measurement of W W / W Z → ℓ ν q q ' production with the hadronically decaying boson reconstructed as one or two jets in pp collisions at s = 8 TeV with ATLAS, and constraints on anomalous gauge couplings

This paper presents a study of the production of WW or WZ boson pairs, with one W boson decaying to e ν or μ ν and one W or Z boson decaying hadronically. The analysis uses 20.2 fb - 1 ofs = 8 TeV pp collision data, collected by the ATLAS detector at the Large Hadron Collider. Cross-sections for WW / WZ production are measured in high- p T fiducial regions defined close to the experimental event selection. The cross-section is measured for the case where the hadronically decaying boson is reconstructed as two resolved jets, and the case where it is reconstructed as a single jet. The transverse momentum distribution of the hadronically decaying boson is used to search for new physics. Observations are consistent with the Standard Model predictions, and 95% confidence intervals are calculated for parameters describing anomalous triple gauge-boson couplings.

Fiducial, total and differential cross-section measurements of t-channel single top-quark production in pp collisions at 8 TeV using data collected by the ATLAS detector

Detailed measurements of t-channel single top-quark production are presented. They use 20.2 fb[Formula: see text] of data collected by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of 8 TeV at the LHC. Total, fiducial and differential cross-sections are measured for both top-quark and top-antiquark production. The fiducial cross-section is measured with a precision of 5.8% (top quark) and 7.8% (top antiquark), respectively. The total cross-sections are measured to be [Formula: see text] for top-quark production and [Formula: see text] for top-antiquark production, in agreement with the Standard Model prediction. In addition, the ratio of top-quark to top-antiquark production cross-sections is determined to be [Formula: see text]. The differential cross-sections as a function of the transverse momentum and rapidity of both the top quark and the top antiquark are measured at both the parton and particle levels. The transverse momentum and rapidity differential cross-sections of the accompanying jet from the t-channel scattering are measured at particle level. All measurements are compared to various Monte Carlo predictions as well as to fixed-order QCD calculations where available.

Search for the Dimuon Decay of the Higgs Boson in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

A search for the dimuon decay of the Higgs boson was performed using data corresponding to an integrated luminosity of 36.1  fb^{-1} collected with the ATLAS detector in pp collisions at sqrt[s]=13  TeV at the Large Hadron Collider. No significant excess is observed above the expected background. The observed (expected) upper limit on the cross section times branching ratio is 3.0 (3.1) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125 GeV. When combined with the pp collision data at sqrt[s]=7  TeV and sqrt[s]=8  TeV, the observed (expected) upper limit is 2.8 (2.9) times the Standard Model prediction.

Measurements of electroweak [Formula: see text] production and constraints on anomalous gauge couplings with the ATLAS detector

Measurements of the electroweak production of a W boson in association with two jets at high dijet invariant mass are performed using [Formula: see text] 7 and 8 [Formula: see text] proton-proton collision data produced by the Large Hadron Collider, corresponding respectively to 4.7 and 20.2 fb[Formula: see text] of integrated luminosity collected by the ATLAS detector. The measurements are sensitive to the production of a W boson via a triple-gauge-boson vertex and include both the fiducial and differential cross sections of the electroweak process.

Jet reconstruction and performance using particle flow with the ATLAS Detector

This paper describes the implementation and performance of a particle flow algorithm applied to 20.2 fb[Formula: see text] of ATLAS data from 8 TeV proton-proton collisions in Run 1 of the LHC. The algorithm removes calorimeter energy deposits due to charged hadrons from consideration during jet reconstruction, instead using measurements of their momenta from the inner tracker. This improves the accuracy of the charged-hadron measurement, while retaining the calorimeter measurements of neutral-particle energies. The paper places emphasis on how this is achieved, while minimising double-counting of charged-hadron signals between the inner tracker and calorimeter. The performance of particle flow jets, formed from the ensemble of signals from the calorimeter and the inner tracker, is compared to that of jets reconstructed from calorimeter energy deposits alone, demonstrating improvements in resolution and pile-up stability.

Identification of OAT1/OAT3 as Contributors to Cisplatin Toxicity

Cisplatin is among the most widely used anticancer drugs and known to cause a dose‐limiting nephrotoxicity, which is partially dependent on the renal uptake carrier OCT2. We here report a previously unrecognized, OCT2‐independent pathway of cisplatin‐induced renal injury that is mediated by the organic anion transporters OAT1 and OAT3. Using transporter‐deficient mouse models, we found that this mechanism regulates renal uptake of a mercapturic acid metabolite of cisplatin that acts as a precursor of a potent nephrotoxin. The function of these two transport systems can be simultaneously inhibited by the tyrosine kinase inhibitor nilotinib through noncompetitive mechanisms, without compromising the anticancer properties of cisplatin. Collectively, our findings reveal a novel pathway that explains the fundamental basis of cisplatin‐induced nephrotoxicity, with potential implications for its therapeutic management.

Search for dark matter at [Formula: see text] in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector

Results of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb[Formula: see text]  of proton-proton collisions at a centre-of-mass energy of [Formula: see text], is in agreement with the Standard Model expectations, model-independent limits are set on the fiducial cross section for the production of events in this final state. Exclusion limits are also placed in models where dark-matter candidates are pair-produced. For dark-matter production via an axial-vector or a vector mediator in the s-channel, this search excludes mediator masses below 750-[Formula: see text] for dark-matter candidate masses below 230-[Formula: see text] at 95% confidence level, depending on the couplings. In an effective theory of dark-matter production, the limits restrict the value of the suppression scale [Formula: see text] to be above [Formula: see text] at 95% confidence level. A limit is also reported on the production of a high-mass scalar resonance by processes beyond the Standard Model, in which the resonance decays to [Formula: see text] and the Z boson subsequently decays into neutrinos.

Measurement of jet fragmentation in Pb+Pb and pp collisions at sNN=2.76 TeV with the ATLAS detector at the LHC

The distributions of transverse momentum and longitudinal momentum fraction of charged particles in jets are measured in Pb+Pb and pp collisions with the ATLAS detector at the LHC. The distributions are measured as a function of jet transverse momentum and rapidity. The analysis utilises an integrated luminosity of 0.14 nb - 1 of Pb+Pb data and 4.0 pb - 1 of pp data collected in 2011 and 2013, respectively, at the same centre-of-mass energy of 2.76 TeV per colliding nucleon pair. The distributions measured in pp collisions are used as a reference for those measured in Pb+Pb collisions in order to evaluate the impact on the internal structure of jets from the jet energy loss of fast partons propagating through the hot, dense medium created in heavy-ion collisions. Modest but significant centrality-dependent modifications of fragmentation functions in Pb+Pb collisions with respect to those in pp collisions are seen. No significant dependence of modifications on jet p T and rapidity selections is observed except for the fragments with the highest transverse momenta for which some reduction of yields is observed for more forward jets.

[Research on the effect of iodinate contrast agent on the DNA radiation damage at CT]

Objective: To evaluate the effect of iodinate contrast agent (ICA) on the formation of DNA double-stand breaks (DSBs) in human peripheral blood lymphocytes during computed tomography (CT) examinations. Methods: Peripheral venous blood (16 ml/person) of 36 volunteers were collected during the period of February to May 2016. Each blood sample was divided into 8 tubes and 4 groups on average, which were marked as groups of A, B, C, D randomly. 25 μl ICA was respectively added into one tube of each group and the groups of B, C, D accepted the same CT scan for once, twice and three times. The lymphocytes in these blood samples were separated by using density-gradient centrifugation, fixed and immunostained with γH2AX antibody. The average number of phosphorylated histone H2AX (γH2AX) foci per lymphocyte was counted under a fluorescence microscopy. Results: The numbers of γH2AX foci were increased approximately 82.9% ((0.064±0.025) vs (0.035±0.010) foci/cell) if ICA was simply added into the blood. With the increase of CT radiation, the foci numbers of the groups of B, C, D would increase and the samples containing ICA could have a more amount of foci numbers than those without ICA (B: (1.217±0.158) vs (0.774±0.258); C: (2.128±0.185) vs (1.569±0.201); D: (3.812±0.490) vs (2.938±0.480) foci/cell). The more radiation it had, the more significant the difference of foci numbers would be ((0.489±0.323), (0.549±0.278), (0.692±0.462) foci/cell). Conclusion: The ICA itself can lead to an increase of the DSBs level and the application of ICA can amplify the DNA damage as assessed with γH2AX foci formation during diagnostic X-ray procedures.