3,136 research outputs found
Exploratory radiomic features from integrated 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging are associated with contemporaneous metastases in oesophageal/gastroesophageal cancer
No full textPurpose: To determine if 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) features are associated with contemporaneous metastases in patients with oesophageal/gastroesophageal cancer.
Methods: Following IRB approval and informed consent, patients underwent a staging PET/MRI following 18F-FDG injection (326±28 MBq) and 156 ± 23 minutes uptake time. First- order histogram and second-order grey level co-occurrence matrix features were computed for PET standardized uptake value (SUV) and MRI T1-W, T2-W, diffusion weighted (DWI) and apparent diffusion coefficient (ADC) images for the whole tumour volume. K-means clustering assessed the correlation of feature-pairs with metastases. Multivariate analysis of variance (MANOVA) was performed to assess the statistical separability of the groups identified by feature-pairs. Sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) were calculated for these features and compared with SUVmax, ADCmean and maximum diameter alone for predicting contemporaneous metastases.
Results: 20 patients (18 males, 2 female; median 67 years, range: 52-86) comprised the final study cohort; 10 patients had metastases. Lower second-order SUV entropy combined with higher second-order ADC entropy were the best feature-pair for discriminating metastatic patients, MANOVA p-value <0.001 (SN=80%, SP=80%, PPV=80%, NPV=80%, ACC=80%). SUVmax (SN=30%, SP=80%, PPV=60%, NPV=53%, ACC=55%), ADCmean (SN = 20%, SP = 70%, PPV = 40%, NPV = 47%, ACC = 45%) and tumour maximum diameter (SN=10%, SP=90%, PPV=50%, NPV=50%, ACC=50%) had poorer sensitivity and accuracy.
Conclusion: High ADC entropy combined with low SUV entropy is associated with a higher prevalence of metastases and a promising initial signature for future study
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Effects of calcium channel blockers on pharmacologically induced contractions of rainbow trout (Oncorhynchus mykiss) intestine
No full textPT: J; CR: BERRIDGE MJ, 1988, P R SOC LONDON B, V234, P359 BRINK C, 1981, J PHARMACOL EXP THER, V217, P592 BURKA JF, 1989, ANIMAL DRUGS FOOD SA, P110 BURKA JF, 1989, CAN J PHYSIOL PHARM, V67, P477 BURKA JF, 1990, IN PRESS CAN J PHYSL, V68 BURNSTOCK G, 1958, BRIT J PHARMACOL CHE, V13, P216 BURNSTOCK G, 1959, Q J MICROSC SCI, V100, P199 CARPENTER JR, 1986, J PHARMACOL METHOD, V15, P283 COOK DA, 1977, FED PROC, V36, P2584 HOAR WS, 1967, LABORATORY COMPANION ISHIKAWA S, 1985, BRIT J PHARMACOL, V86, P789 JANIS RA, 1983, BIOCHEM PHARMACOL, V32, P3499 JANIS RA, 1983, J MED CHEM, V26, P775 KARAKI H, 1988, LIFE SCI, V42, P111 KITCHEN I, 1984, TXB INVITRO PRACTICA LEFF P, 1987, J PHARMACOL EXP THER, V240, P284 SAIDA K, 1983, BLOOD VESSELS, V20, P105 SCHWARTZ A, 1984, ANNU REV MED, V35, P325 SMALL RC, 1982, BRIT J PHARMACOL, V77, P45 SPEDDING M, 1988, ANN NY ACAD SCI, V522, P248 VANBREEMEN C, 1979, PHARMACOL REV, V30, P167 WOLOWYK MW, 1987, J THERM BIOL, V12, P87; NR: 22; TC: 2; J9: FISH PHYSIOL BIOCHEM; PG: 7; GA: EG368Source type: Electronic(1
Adaptive sampling in two-phase designs: a biomarker study for progression in arthritis
No full textResponse‐dependent two‐phase designs are used increasingly often in epidemiological studies to ensure sampling strategies offer good statistical efficiency while working within resource constraints. Optimal response‐dependent two‐phase designs are difficult to implement, however, as they require specification of unknown parameters. We propose adaptive two‐phase designs that exploit information from an internal pilot study to approximate the optimal sampling scheme for an analysis based on mean score estimating equations. The frequency properties of estimators arising from this design are assessed through simulation, and they are shown to be similar to those from optimal designs. The design procedure is then illustrated through application to a motivating biomarker study in an ongoing rheumatology research program.
This is the peer-reviewed version of the following article: McIsaac, M. A., & Cook, R. J. (2015). Adaptive sampling in two-phase designs: a biomarker study for progression in arthritis. Statistics In Medicine, 34(21), 2899-2912. doi:10.1002/sim.6523, which has been published in final form at https://doi.org/10.1002/sim.6523. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Version
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
No full textThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
Observation of J/ψ-pair production in pp collisions at √s=7 TeV
No full textThe production of J/ψ pairs in proton–proton collisions at a centre-of-mass energy of 7 TeV has been observed using an integrated luminosity of 37.5 pb−1 collected with the LHCb detector. The production cross-section for pairs with both J/ψ in the rapidity range 2 < yJ/ψ < 4.5 and transverse momentum pJ/ψ T <10 GeV/c is σJ/ψJ/ψ =5.1±1.0±1.1 nb, where the first uncertainty is statistical and the second systematic
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