Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector

This Letter presents the first study of Higgs boson production in association with a vector boson (V=W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at sqrt[s]=13  TeV and corresponding to an integrated luminosity of 137  fb^{-1}. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb[over ¯]. Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The VH production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250-450, 450-650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ=1.4_{-0.9}^{+1.0} and the corresponding cross section is 3.1±1.3(stat)_{-1.4}^{+1.8}(syst)  pb.

Measurement of the Centrality Dependence of the Dijet Yield in p+Pb Collisions at sqrt[s_{NN}]=8.16 TeV with the ATLAS Detector

ATLAS measured the centrality dependence of the dijet yield using 165  nb^{-1} of p+Pb data collected at sqrt[s_{NN}]=8.16  TeV in 2016. The event centrality, which reflects the p+Pb impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter. The central-to-peripheral ratio of the scaled dijet yields, R_{CP}, is evaluated, and the results are presented as a function of variables that reflect the kinematics of the initial hard parton scattering process. The R_{CP} shows a scaling with the Bjorken x of the parton originating from the proton, x_{p}, while no such trend is observed as a function of x_{Pb}. This analysis provides unique input to understanding the role of small proton spatial configurations in p+Pb collisions by covering parton momentum fractions from the valence region down to x_{p}∼10^{-3} and x_{Pb}∼4×10^{-4}.

The performance of large language models in intercollegiate Membership of the Royal College of Surgeons examination

INTRODUCTION

Large language models (LLM), such as Chat Generative Pre-trained Transformer (ChatGPT) and Bard utilise deep learning algorithms that have been trained on a massive data set of text and code to generate human-like responses. Several studies have demonstrated satisfactory performance on postgraduate examinations, including the United States Medical Licensing Examination. We aimed to evaluate artificial intelligence performance in Part A of the intercollegiate Membership of the Royal College of Surgeons (MRCS) examination.

METHODS

The MRCS mock examination from Pastest, a commonly used question bank for examinees, was used to assess the performance of three LLMs: GPT-3.5, GPT 4.0 and Bard. Three hundred mock questions were input into the three LLMs, and the responses provided by the LLMs were recorded and analysed. The pass mark was set at 70%.

RESULTS

The overall accuracies for GPT-3.5, GPT 4.0 and Bard were 67.33%, 71.67% and 65.67%, respectively (p = 0.27). The performances of GPT-3.5, GPT 4.0 and Bard in Applied Basic Sciences were 68.89%, 72.78% and 63.33% (p = 0.15), respectively. Furthermore, the three LLMs obtained correct answers in 65.00%, 70.00% and 69.17% of the Principles of Surgery in General questions (p = 0.67). There were no differences in performance in the overall and subcategories among the three LLMs.

CONCLUSIONS

Our findings demonstrated satisfactory performance for all three LLMs in the MRCS Part A examination, with GPT 4.0 the only LLM that achieved the pass mark set.

Search for New Phenomena in Two-Body Invariant Mass Distributions Using Unsupervised Machine Learning for Anomaly Detection at sqrt[s]=13 TeV with the ATLAS Detector

Searches for new resonances are performed using an unsupervised anomaly-detection technique. Events with at least one electron or muon are selected from 140  fb^{-1} of pp collisions at sqrt[s]=13  TeV recorded by ATLAS at the Large Hadron Collider. The approach involves training an autoencoder on data, and subsequently defining anomalous regions based on the reconstruction loss of the decoder. Studies focus on nine invariant mass spectra that contain pairs of objects consisting of one light jet or b jet and either one lepton (e,μ), photon, or second light jet or b jet in the anomalous regions. No significant deviations from the background hypotheses are observed. Limits on contributions from generic Gaussian signals with various widths of the resonance mass are obtained for nine invariant masses in the anomalous regions.

Novice learners' perspectives on obstetric airway crisis decision-making training using virtual reality simulation

BACKGROUND

Current training on managing an obstetric difficult airway crisis is likely inadequate, as real-life opportunities to practice are rare. Frequent simulation training sessions could be helpful but are resource intensive. Virtual reality (VR) simulation training may be a potential tool to complement existing simulation curricula.

METHODS

In this pilot qualitative study, a VR simulation scenario of an obstetric airway crisis was designed to test the decision-making of novice learners rotating through obstetric anesthesia training. Individual interviews were conducted pre-VR to assess learning needs and post-VR to assess perspectives on utilizing the VR teaching tool. The interviews were transcribed and thematically analyzed.

RESULTS

Twenty-one residents were recruited and participated in the study. Analysis of pre-VR interviews identified three major themes, including gaps in the current curriculum, lack of confidence in managing obstetric difficult airway crises, and recognition that simulation is resource intensive. Post-VR interview themes revealed that VR could be helpful in learning decision-making under stress. Suggested improvements included better video and audio quality, and adding haptic feedback and potential multiplayer features in the future.

CONCLUSION

We identified the advantages of VR simulation and its potential as an intervention to address gaps in our curriculum. Areas of improvement were identified for more effective future implementation.

Observation of WZγ Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter reports the observation of WZγ production and a measurement of its cross section using 140.1±1.2  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The WZγ production cross section, with both the W and Z bosons decaying leptonically, pp→WZγ→ℓ^{'}^{±}νℓ^{+}ℓ^{-}γ (ℓ^{(^{'})}=e, μ), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01±0.30(stat)±0.16(syst)  fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06  fb. The observed significance of the WZγ signal is 6.3σ, compared with an expected significance of 5.0σ.

Combined Measurement of the Higgs Boson Mass from the H→γγ and H→ZZ^{*}→4ℓ Decay Channels with the ATLAS Detector Using sqrt[s]=7, 8, and 13 TeV pp Collision Data

A measurement of the mass of the Higgs boson combining the H→ZZ^{*}→4ℓ and H→γγ decay channels is presented. The result is based on 140  fb^{-1} of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11±0.09(stat)±0.06(syst)=125.11±0.11  GeV. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics.

Search for Dark Photons in Rare Z Boson Decays with the ATLAS Detector

A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139  fb^{-1} of sqrt[s]=13  TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}ϵ^{2}, in the dark photon mass range of [5, 40] GeV except for the ϒ mass window [8.8, 11.1] GeV. This search explores new parameter space not previously excluded by other experiments.

Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector

This Letter reports the observation of single top quarks produced together with a photon, which directly probes the electroweak coupling of the top quark. The analysis uses 139  fb^{-1} of 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. Requiring a photon with transverse momentum larger than 20 GeV and within the detector acceptance, the fiducial cross section is measured to be 688±23(stat) _{-71}^{+75}(syst)  fb, to be compared with the standard model prediction of 515_{-42}^{+36}  fb at next-to-leading order in QCD.

Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02 TeV with the ATLAS Detector

This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02  TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72  nb^{-1} and 257  pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158 Collapse

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Measurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings

A key open question in the study of multiparticle production in high-energy pp collisions is the relationship between the "ridge"-i.e., the observed azimuthal correlations between particles in the underlying event that extend over all rapidities-and hard or semihard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To address this question, two-particle correlations are measured in pp collisions at sqrt[s]=13  TeV using data collected by the ATLAS experiment at the LHC, with an integrated luminosity of 15.8  pb^{-1}, in two different configurations. In the first case, charged particles associated with jets are excluded from the correlation analysis, while in the second case, correlations are measured between particles within jets and charged particles from the underlying event. Second-order flow coefficients, v_{2}, are presented as a function of event multiplicity and transverse momentum. These measurements show that excluding particles associated with jets does not affect the measured correlations. Moreover, particles associated with jets do not exhibit any significant azimuthal correlations with the underlying event, ruling out hard processes contributing to the ridge.

Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector

A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 140  fb^{-1} recorded by the ATLAS experiment at LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds are estimated based on a hybrid approach involving Monte Carlo simulations and data-driven methods. Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-J/ψ channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the J/ψ+ψ(2S) channel. The fitted masses and decay widths of the structures are reported.

Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector

This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44  nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057 Collapse

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Acute and Late Toxicities in Patients with Collagen Vascular Disease Receiving Curative-Intent Intensity-Modulated Radiotherapy to the Head and Neck Region

PURPOSE/OBJECTIVE(S)

Historically, collagen vascular disease (CVD) was considered at least a relative contraindication to radiotherapy (RT). However, more recent meta-analyses suggest that for patients with certain CVDs such as rheumatoid arthritis (RA), there may not be an increased risk for severe toxicities, while for patients with CVDs such as systemic lupus erythematosus (SLE), dermatomyositis (DM) and scleroderma, there may be as high as a 2- to 4-fold risk for severe toxicities compared to patients without CVD. There are also data to suggest that patients with head and neck cancer (HNC) and comorbid CVD are at especially high risk of severe toxicities from RT. This study evaluated the hypothesis that among patients with HNC treated with curative-intent intensity-modulated radiation therapy (IMRT), patients with SLE or DM were more likely to have had late grade ≥3 toxicity rates compared to patients with other CVDs.

MATERIALS/METHODS

A total of 23 patients who had HNC with comorbid CVD and received IMRT between 2005-2022 were included. Acute (≤90 days after completion of RT) and late (>90 days) toxicities were retrospectively classified using CTCAE v5.0. Toxicity rates were compared across CVD groups using Chi-squared tests.

RESULTS

Median follow-up was 56.3 months. The most common CVDs were RA (9 patients, 39%), SLE (4 patients, 17%), and DM (4 patients, 17%). Median total RT dose was 66 Gy (range: 48-70 Gy), in 1.8-2.4 Gy fractions. Nine (39%) patients received concurrent chemotherapy. 14 (61%) patients had mucosal squamous cell carcinoma (SCC), 3 (13%) had cutaneous SCC, 2 (9%) had nasal cavity/paranasal sinus tumors, 2 (9%) had salivary gland tumors, 1 (4%) had cutaneous melanoma, and 1 (4%) had mucosal melanoma. Eight (35%) patients experienced acute grade ≥3 toxicities, and 3 (13%) patients experienced late grade ≥3 toxicities (Table 1). No patients had grade≥4 toxicities. Patients with SLE or DM did not have significantly higher risk of late grade ≥3 toxicities compared to those with other CVDs (25% vs. 7%, p = 0.21).

CONCLUSION

In this small sample size of patients with HNC and comorbid CVD, definitive or post-operative IMRT was associated with approximately 35% acute and 15% late severe toxicity rates. While SLE/DM were associated with >3-fold late grade ≥3 toxicities, this association needs to be confirmed with larger data sets.

Quantifying the Dosimetric Impact of Tissue Hounsfield Unit Assignment in Deep Learning-based Synthetic CT Images For MRI-Only Radiation Therapy of The Head and Neck

PURPOSE/OBJECTIVE(S)

MRI-only simulation for head and neck (HN) radiotherapy (RT) could allow for single-image modality planning with excellent soft tissue contrast. In the MRI-only simulation workflow, synthetic CTs (sCTs) are generated from MRI to provide electron density information for dose calculation. Bone/air regions produce little MRI signal which could lead to electron density misclassification in sCTs. Establishing the dosimetric impact of this error could inform quality assurance (QA) procedures using MRI-only RT planning. In this study we quantify differences in Hounsfield Unit (HU) values between paired CT/ sCTs of HN cancer patients and investigate the dosimetric impact on clinical treatment plans.

MATERIALS/METHODS

Fourteen patients with head and neck cancer undergoing same-day CT and 3T MRI simulation were retrospectively identified. MRIs were deformed to the CT using multimodal deformable image registration. SCTs were generated from T1w DIXON MRI using a commercially available deep learning-based generator (MRIplanner, Spectronics). Tissue voxel assignment was quantified by creating a CT-derived HU threshold contour. CT/sCT HU differences for anatomical/target contours and tissue classification regions including air (<-250HU), adipose tissue (-250HU to -51HU), soft tissue (-50HU to 199HU), spongy (200HU to 499HU) and cortical bone (> 500HU) were quantified. T-test was used to determine if sCT/CT HU differences were significant. The frequency of structures that had a HU difference >70HU (the CT window-width setting for intra-cranial structures) was computed to establish structure classification accuracy. Clinical IMRT treatment plans created on CTs were retrospectively recalculated on sCT images using compared using the gamma metric.

RESULTS

The mean ratio of sCT HUs relative to CT for air, adipose tissue, soft tissue, spongy and cortical bone were 1.7±0.3, 1.1±0.1, 1.0±0.1, 0.9±0.1 and 0.8±0.1 (value of 1 indicates perfect agreement). T-tests (significance set at t = 0.05) identified differences in HU values for air, spongy and cortical bone in sCT images compared to CT. The structures with sCT/CT HU differences > 70HU were the L/R cochlea and mandible, occurring in >78% of the tested cohort. These structures contain dense bone/air interfaces. Plans recalculated on sCTs yielded global/local gamma pass rates of 98.7%±1.2% (3mm,3%) and 95.5%±2.5% (1mm,1%). Mean differences in D95, D50, D10 and D2 dose volume histogram (DVH) metrics for organ-at-risk (OAR) and planning tumor volumes (PTV) were 0.8%±1.5% and 2.1% ± 1.2% respectively.

CONCLUSION

In this cohort, HU differences in sCTs were observed but did not translate into a reduction in gamma pass rates and OAR/PTV DVH metrics. The acquisition of additional training data such as ultrashort echo time MRI could improve bone/air contrast and reduce bone/air sCT misclassifications. Further studies will establish the variation in sCT dosimetric accuracy using a larger retrospective cohort to inform QA limits on clinical sCT usage.

Toxicity and Dosimetric Analysis of Reirradiation of Head and Neck Cancers with High Dose Rate Brachytherapy

PURPOSE/OBJECTIVE(S)

Reirradiation (reRT) of recurrent or second primary head and neck cancers (HNC) after prior curative-intent external beam radiotherapy (EBRT) has historically achieved local control (LC) rates of 40-50% and been associated with high grade toxicity rates estimated at 25-50%. This study evaluated the hypothesis that patients with small reRT target volumes could be selected for high dose rate brachytherapy (HDR-BT) reRT and achieve similar LC without excess toxicity.

MATERIALS/METHODS

Included were all patients with HNC squamous cell carcinoma treated with HDR-BT after having previously received curative-intent EBRT for primary HNC from 2000-2021. Patients were selected by a multidisciplinary tumor board to be appropriate candidates for HDR-BT reRT without EBRT generally for definitive or adjuvant treatment of small primary tumors without neck nodal metastases. Univariate analysis was performed using the logistic regression model. Survival outcomes were estimated with the Kaplan Meier method.

RESULTS

Twenty-three patients were evaluated. Median follow up time was 19mo. Median age at time of HDR-BT was 64 years. Thirteen patients (57%) were treated for recurrent HNC, of which 7 were in the oral cavity (OC) and 6 were the oropharynx (OPX). Ten patients (43%) were treated for a second primary HNC, of which 5 were in the OC and 5 were in the OPX. Median time from completion of EBRT to HDR-BT was 41 (IQR 14-73) mo. Within their reRT course, 11 patients (48%) were treated with HDR-BT after resection, 9 patients (39%) received concurrent hyperthermia, and 7 patients (30%) received chemotherapy. HDR-BT regimens included 600cGy x5 (N = 11), 600cGy x6 (N = 6), 450cGy x8 (N = 1), 1500cGy x1 (N = 1),1000cGy x1 (N = 1), 500cGy x8 (N = 1), and 700cGy x5 (N = 1). One patient who was treated with two implants received 450cGy x 3 followed by 475cGy x5. A median of 5 brachytherapy catheters were used. Actuarial 2-year LC and overall survival rate was 68% and 62%, respectively. Of the 17 HDR-BT reRT plans available for review, median (IQR) target volume was 15.8 (10.6-34.9) cc. Median (IQR) target V100% was 90.6 (89.4-90.0)%, V150% was 50.5 (49.7-54.4)%, and V200% was 25.4 (23.8-29.0)%. Median (IQR) target D90% was 30.1 (29.8-35.5) Gy, and median D1cc was 116.4 (100.5-171.4) Gy. The mandible dose [median (IQR)] was D2cc:15.1(9.48-18.9) Gy; D1cc:16.9(11.1-21.3) Gy; and D1%:18.8(13.4-22.7) Gy. Nine of the 23 patients (39%) experienced ≥G3 toxicity including fistula, soft tissue necrosis, osteoradionecrosis, ulcer, hemorrhage, and dysphagia requiring a chronic feeding tube. Target D90% was associated with ≥G3 toxicity (p = 0.045). For D90% greater than the median of 30Gy, 45% ≥G3 toxicity was observed.

CONCLUSION

This study suggests that HDR-BT for reRT of small recurrent or second primary HNC can provide similar LC without excess high-grade toxicities as compared to historical outcomes with EBRT reRT. Delivery of equivalent doses higher than 30Gy in 5 fractions should be approached with caution.

Identifying Common Topics in Patient Portal Messages with Unsupervised Natural Language Processing

PURPOSE/OBJECTIVE(S)

Patient portal messaging is an increasingly important form of communication between patients and medical providers. This has become particularly relevant in oncology, where patients undergo intense longitudinal treatments that require frequent communication regarding symptoms, appointments, and diagnostic results. The rise in the volume of these messages has significantly increased the workload of medical providers and consequent physician burn-out. Natural language processing (NLP), particularly transformer-based models, may offer an automated approach to characterize the content of patient messages and improve message triage and routing. In this study, we employed a state-of-the-art language model (Bidirectional Encoder Representations from Transformers; BERT) to identify data-derived categories of representative topics from real-world data thereby providing basic information to build an appropriate routing system.

MATERIALS/METHODS

Patient-generated portal messages sent to a messaging pool for a single institution radiation oncology department from 2014 to 2023 were extracted. BERTopic, an NLP-based topic modeling technique based on BERT was optimized for topic modeling of patient messages. Uniform Manifold Approximation and Projection (UMAP) was used to reduce dimensionality and visualize topic relationships across messages. The BERTopic-identified topic categories were subsequently labeled manually by one of the physician investigators. Differences of number of messages over time were assessed using t-tests.

RESULTS

A total of 47,492 messages were retrieved. The average number of messages per month from a single patient ranged from 1 to 18 (median 1.67, interquartile range 1.0-2.4). The total volume of patient messages showed a ten-fold increase over the study period, with 101 messages per month sent in 2014 and 999 messages per month in 2022 (p<0.001). BERTopic initially identified 35 topics whose relationships and degrees of overlap were visualized by UMAP. Due to physician-identified similarities, these topics were reduced into 13 categories. The most frequent topic category was messages about laboratory tests or imaging studies: 24.3%, followed by messages expressing appreciation: 18.9%, scheduling discussions: 15.6%, symptom-related messages: 11%, and treatment-related messages: 10.7%.

CONCLUSION

Patient portal messages sent to a single institution radiation oncology department have increased dramatically in volume since implementation, corresponding to a broader national trend. NLP successfully identified common subject themes across patient messages, many of which are related to scheduling. This presents potential opportunities to apply NLP to automate message routing in the future.

RAPid SimPLE (RAPPLE) Targeted Radiation Treatment vs. Whole Brain Radiotherapy: A Retrospective Study of Matched Patients with Brain Metastases and Poor Prognosis

PURPOSE/OBJECTIVE(S)

Patients with brain metastases and poor prognosis are often treated with whole brain radiotherapy (WBRT) which can cause a variety of side effects. Our institution devised a new brain-sparing radiotherapy technique to treat multiple brain metastasis for patients whose poor prognosis does not warrant SRS. This study compares the oncologic outcomes of matched patients treated with RAPPLE and WBRT.

MATERIALS/METHODS

RAPPLE uses single-isocenter, coplanar volumetric modulated arc therapy and a non-stereotactic head-shell with IntegraBite™. Brain metastasis were contoured in a single gross tumor volume and expanded by 3 mm to create a planning target volume, of which 99.5% was covered with 95-110% of 20 Gy in 5 fractions. Patients treated with a first course of RAPPLE from January 2017 to December 2021 were identified in an institutional database. Using age, cancer diagnosis, and treatment date, we identified a matched cohort of patients receiving a first course of WBRT with 20 Gy in 5 fractions. Overall survival (OS) was calculated using the Kaplan-Meier method, and intracranial progression was calculated using cumulative incidence with a competing risk of death. Log-rank, Cox regression and Fine-Gray analyses were used for comparisons. Paired t-tests were used to compare patient-reported fatigue measured using 5-level Likert scales before and 2-6 weeks after radiotherapy.

RESULTS

The RAPPLE and WBRT cohorts each had 137 patients. The matched median age was 69 years. Primary diagnoses were lung cancer (72%) and other cancers (28%). The minimum, median, and maximum numbers of metastases treated with RAPPLE were 1, 3, and 18, respectively. The median Karnofsky Performance Score (KPS) was 70 in both cohorts. The median survival was 4.1 months for RAPPLE and 4.2 months for WBRT, and the 18-month OS was 11% for RAPPLE and 12% for WBRT (log-rank p = 0.8). On multivariable analysis, KPS, diagnosis, extracranial disease, and use of systemic therapy before and after RT were predictive of OS, but use of RAPPLE vs. WBRT was not (HR = 0.97, 95% CI: 0.75-1.25, p = 0.8). The 18-month cumulative incidence of intracranial progression was 0.49 for RAPPLE and 0.37 for WBRT (p = 0.04). After RAPPLE, 17% required more focal RT and 4% required salvage WBRT, while after WBRT, 3% required focal RT and 4% required repeat WBRT. After RAPPLE, mean patient-reported fatigue remained stable from baseline to first follow-up (2.18 vs. 2.27, p = 0.9), but, after WBRT, it worsened from baseline to first follow-up (1.95 vs. 2.63, p = 0.002).

CONCLUSION

As expected, after RAPPLE, more targeted radiotherapy was required for intracranial progression, but there was no difference in OS between the RAPPLE and WBRT cohorts. Patients reported significantly worse fatigue after WBRT. Almost all patients (96%) treated with RAPPLE avoided WBRT.

Strong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02 TeV from ATLAS

Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including pp and p+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36  nb^{-1} of p+Pb and 3.6  pb^{-1} of pp collisions at 5.02 TeV. The yields of charged hadrons with p_{T}^{ch}>0.5  GeV near and opposite in azimuth to jets with p_{T}^{jet}>30 or 60 GeV, and the ratios of these yields between p+Pb and pp collisions, I_{pPb}, are reported. The collision centrality of p+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The I_{pPb} values are consistent with unity within a few percent for hadrons with p_{T}^{ch}>4  GeV at all centralities. These data provide new, strong constraints that preclude almost any parton energy loss in central p+Pb collisions.

Search for Heavy Neutral Leptons in Decays of W Bosons Using a Dilepton Displaced Vertex in sqrt[s]=13 TeV pp Collisions with the ATLAS Detector

A search for a long-lived, heavy neutral lepton (N) in 139  fb^{-1} of sqrt[s]=13  TeV pp collision data collected by the ATLAS detector at the Large Hadron Collider is reported. The N is produced via W→Nμ or W→Ne and decays into two charged leptons and a neutrino, forming a displaced vertex. The N mass is used to discriminate between signal and background. No signal is observed, and limits are set on the squared mixing parameters of the N with the left-handed neutrino states for the N mass range 3  GeV Collapse

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Test of CP Invariance in Higgs Boson Vector-Boson-Fusion Production Using the H→γγ Channel with the ATLAS Detector

A test of CP invariance in Higgs boson production via vector-boson fusion has been performed in the H→γγ channel using 139  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS detector at the LHC. The optimal observable method is used to probe the CP structure of interactions between the Higgs boson and electroweak gauge bosons, as described by an effective field theory. No sign of CP violation is observed in the data. Constraints are set on the parameters describing the strength of the CP-odd component in the coupling between the Higgs boson and the electroweak gauge bosons in two effective field theory bases: d[over ˜] in the HISZ basis and c_{HW[over ˜]} in the Warsaw basis. The results presented are the most stringent constraints on CP violation in the coupling between Higgs and weak bosons. The 95% C.L. constraint on d[over ˜] is derived for the first time and the 95% C.L. constraint on c_{HW[over ˜]} has been improved by a factor of 5 compared to the previous measurement.

Microsecond Isomer at the N=20 Island of Shape Inversion Observed at FRIB

Excited-state spectroscopy from the first experiment at the Facility for Rare Isotope Beams (FRIB) is reported. A 24(2)-μs isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV γ rays in coincidence with ^{32}Na nuclei. This is the only known microsecond isomer (1  μs≤T_{1/2}<1  ms) in the region. This nucleus is at the heart of the N=20 island of shape inversion and is at the crossroads of the spherical shell-model, deformed shell-model, and ab initio theories. It can be represented as the coupling of a proton hole and neutron particle to ^{32}Mg, ^{32}Mg+π^{-1}+ν^{+1}. This odd-odd coupling and isomer formation provides a sensitive measure of the underlying shape degrees of freedom of ^{32}Mg, where the onset of spherical-to-deformed shape inversion begins with a low-lying deformed 2^{+} state at 885 keV and a low-lying shape-coexisting 0_{2}^{+} state at 1058 keV. We suggest two possible explanations for the 625-keV isomer in ^{32}Na: a 6^{-} spherical shape isomer that decays by E2 or a 0^{+} deformed spin isomer that decays by M2. The present results and calculations are most consistent with the latter, indicating that the low-lying states are dominated by deformation.

COVID-19 vaccination-related exacerbation of seizures in persons with epilepsy

Although vaccines are generally safe in persons with epilepsy (PWE), seizures can be associated with vaccination, including COVID-19. This study assessed the occurrence of COVID-19 vaccination-related seizure exacerbations in PWE. Adult PWE who had received a COVID-19 vaccine were consecutively recruited at a tertiary epilepsy clinic between June 2021 and April 2022. Patient demographics, including epilepsy history, vaccination details, and reported adverse effects were recorded. Seizure exacerbation, defined as occurring within one week of vaccination, was assessed. Five hundred and thirty PWE received the COVID-19 vaccine. 75 % received the Comirnaty (Pfizer) vaccine as their initial dose. Most patients (72 %) were taking ≥ 2 antiseizure medications (ASM) and had focal epilepsy (73 %). One-third were 12 months seizure free at their first vaccination. 13 patients (2.5 %) reported a seizure exacerbation following their first vaccination, three of whom required admission. None were seizure-free at baseline. Six of these patients (46 %) had a further exacerbation of seizures with their second vaccine. An additional four patients reported increased seizures only with the second vaccine dose. Seizure exacerbations are infrequently associated with COVID-19 vaccination, mainly in patients with ongoing seizures. The likelihood of COVID-19 infection complications in PWE outweighs the risk of vaccination-related seizure exacerbations.

Crossing N=28 Toward the Neutron Drip Line: First Measurement of Half-Lives at FRIB

New half-lives for exotic isotopes approaching the neutron drip-line in the vicinity of N∼28 for Z=12-15 were measured at the Facility for Rare Isotope Beams (FRIB) with the FRIB decay station initiator. The first experimental results are compared to the latest quasiparticle random phase approximation and shell-model calculations. Overall, the measured half-lives are consistent with the available theoretical descriptions and suggest a well-developed region of deformation below ^{48}Ca in the N=28 isotones. The erosion of the Z=14 subshell closure in Si is experimentally confirmed at N=28, and a reduction in the ^{38}Mg half-life is observed as compared with its isotopic neighbors, which does not seem to be predicted well based on the decay energy and deformation trends. This highlights the need for both additional data in this very exotic region, and for more advanced theoretical efforts.

National audit of non-melanoma skin cancer excisions performed by plastic surgery in the UK

A national, multi-centre audit of non-melanoma skin cancer excisions by plastic surgery.

Development and validation of non-invasive endothelial shear stress (ESS) estimations of coronary artery haemodynamics using computational modelling

Background

Vascular remodelling is influenced by various biomechanical forces such as endothelial shear stress (ESS) and is associated with development and progression of coronary artery disease (CAD). ESS is the parallel frictional force exerted by blood flow on the endothelial luminal surface of the arterial wall. While ESS may not be the only cause of atherosclerosis, it is postulated that low ESS creates a pro-atherogenic environment and high ESS is athero-protective. Computational fluid dynamics (CFD) is an engineering method used to analyse fluid flow and has been increasingly applied to simulate ESS in cardiovascular research. However, current CFD-derived ESS estimates have never been validated and can display significant variability between research groups.

Purpose

This study aims to provide a comparative analysis of coronary flow using in-silico modelling of coronary flow and particle image velocimetry (PIV).

Methods

A proximal left anterior descending (pLAD) coronary phantom model was constructed from a patient who had received same day cardiac computed tomography angiography (CTCA) and invasive coronary haemodynamic (Combowire XT) assessment. Patient-specific coronary flow data was applied to CFD boundary conditions and a mock circulatory loop. CFD was validated using PIV under steady flow in a 4-times-scaled model. Same plane velocity field and flow patterns (at mid-luminal of pLAD) from both in-silico and in-vivo data were compared and analysed.

Results

Mean velocity contours and magnitude were analysed from CFD and PIV. Patient specific average peak velocity obtained from invasive assessment was 0.21m/s. Patient-specific velocity average from CFD was 0.22m/s. The approximated magnitude difference is 4.7%. Both same-axial average cross-sectional velocity estimated by CFD-pLAD and PIV-pLAD are 0.087m/s. Velocity contours and flow patterns simulated in the CFD were also comparable with the PIV results.

Conclusion

Simulation data from CFD correlate well with experimental PIV results. This early data allows for a non-invasive approach to determine patient-specific coronary haemodynamics (such as velocity profiling and ESS) and form the basis of personalising cardiovascular risk. Insights from this work may aid future development of a novel tool that incorporates CFD-derived ESS estimates with patient-specific risk factors to better predict rapid CAD progression.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Cardiac Society of Australia and New Zealand Monash Institute of Medical Engineering

Predictive value of neutrophil-to-lymphocyte ratio for atrial fibrillation and stroke in type 2 diabetes mellitus: a population-based cohort study

Introduction

Neutrophil-to-lymphocyte ratio (NLR) is a routinely available biomarker that reflects systemic inflammation. The study evaluated the predictive value of NLR for ischemic stroke and atrial fibrillation (AF) in patients with type 2 diabetes mellitus.

Methods

This was a population-based cohort study of patients with type 2 diabetes mellitus and complete blood count tests at baseline between January 1st, 2009 to December 31st, 2009 at government-funded hospitals/clinics in Hong Kong. Follow-up was until December 31st, 2019 or death.

Results

A total of 85351 patients (age=67.6±13.2 years old, male=48.8%, follow-up=3101±1441 days) were included. Univariable Cox regression found that increased NLR at quartiles 2, 3 and 4 was significantly associated with higher risks of new onset ischemic stroke (HR: 1.28 [1.20–1.37], P&lt;0.001, HR: 1.41 [1.32–1.51], P&lt;0.001 and HR: 1.38 [1.29–1.47], P&lt;0.001) and AF (hazard ratio [HR]: 1.09 [1.02–1.17], P&lt;0.015; HR: 1.28 [1.20–1.37], P&lt;0.001; HR: 1.39 [1.31–1.49], P&lt;0.001) compared to quartile 1. On multivariable analysis, NLR remained a significant predictor of ischemic stroke risk for quartiles 2 and 3 (quartile 2: HR: 1.14 [1.05, 1.22], p=0.001; quartile 3: HR: 1.14 [1.06, 1.23], p&lt;0.001) but not quartile 4 (HR: 1.08 [0.994, 1.17], p=0.070). By contrast, NLR was not predictive of AF after adjusting for confounders (quartile 2: HR: 0.966 [0.874, 1.07], p=0.499; quartile 3: HR: 0.978 [0.884, 1.08], p=0.661; quartile 4: HR: 1.05 [0.935, 1.16], p=0.462).

Conclusion

NLR is a significant predictor of new onset ischaemic stroke but not AF after adjusting for significant confounders.

Funding Acknowledgement

Type of funding sources: None.

Observation of WWW Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter reports the observation of WWW production and a measurement of its cross section using 139  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWW production cross section is measured to be 820±100 (stat)±80 (syst)  fb, approximately 2.6 standard deviations from the predicted cross section of 511±18  fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy.

A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

The standard model of particle physics1-4 describes the known fundamental particles and forces that make up our Universe, with the exception of gravity. One of the central features of the standard model is a field that permeates all of space and interacts with fundamental particles5-9. The quantum excitation of this field, known as the Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the standard model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN10,11. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and W and Z bosons-the carriers of the strong, electromagnetic and weak forces-are studied in detail. Interactions with three third-generation matter particles (bottom (b) and top (t) quarks, and tau leptons (τ)) are well measured and indications of interactions with a second-generation particle (muons, μ) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model.

1078 AUDIT TO IMPROVE APPLICATION OF THE MENTAL CAPACITY ACT ON GERIATRIC WARDS

Introduction

The Mental Capacity Act 2005 (MCA) and Deprivation of Liberty Safeguards (DoLS) are put in place to protect the rights of capacitous patients to make decisions, and in those not deemed to have capacity, the latter ensures that any restrictions are in the patient’s best interests, are appropriate and proportionate. The objective of this audit was to assess whether these tools were being appropriately employed across the four Complex Medical Units (CMU) in the John Radcliffe Hospital, in a patient population in which dementia and delirium are prevalent.

Method

Audit of patient records on CMU wards (first cycle on 15/8/21 n = 74, second cycle on 31/10/21 (n = 74) before and after presentation of the initial audit results. All inpatients were assessed for: AMTS, completion of a MCA (for those with AMTS&lt;8, or an AMTS not done as too unwell), DoLs applications if indicated. Across the wards, baseline patient characteristics and demographics were equal. In the first audit, there were only 16% patients (6) with an MCA out of a possible 38 patients who fulfilled the criteria and out of these, and 2 had a DOLS (5%). After training, involving a presentation given by us about the findings of our audit, together with high level discussions between consultants and registrars, there were 43% patients with an MCA (15 patients), and 14% had appropriate DOLS (5 patients), out of 35 patients. This therefore shows clear improvement in the situation on our wards.

Conclusion

This audit has improved the recognition of patients in whom a capacity assessment is required and the documentation of a MCA being done. Going forward, we suggest all geriatric medicine wards should discuss and audit MCA and DOLS to ensure patients’ rights are suitably protected.

The long term prognostic value of peak left atrial strain in cardiac transplant patients

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial (LA) dysfunction is associated with poorer outcomes in many disease processes. Left atrial strain (LAS) is a novel two-dimensional (2D) quantitative analysis of LA function. Cardiac transplantation directly involves the LA during implantation of the donor heart. Traditional echocardiographic indices after transplantation have demonstrated value in correlating with acute cellular rejection (ACR), morbidity and mortality over short- and long-term follow-up. The prognostic value of LA strain has not been previously investigated in this cohort.

Purpose

We hypothesized that incrementally impaired LA strain in post cardiac transplant patients with varying degrees of ACR may be prognostic of poorer outcomes on long term follow-up.

Methods

87 Heart transplant patients, assessed between 2009 and 2015, underwent transthoracic echocardiography and endomyocardial biopsy. 2D strain analysis on the LV and LA were performed along with traditional echocardiographic parameters. Patients were grouped according to peak LAS (PALS) tertiles and rejection burden history was assessed and grouped according to ACR burden at a median of 12 (±5.4) months post transplantation. The primary endpoint was all-cause mortality at follow-up.

Results

12 patients met the primary endpoint over a median follow-up of 66 ± 51 months. The mean LA PALS was significantly different across the tertiles (lowest tertile 12.29 ± 2.5% vs middle tertile 17.89 ± 1.1% vs highest tertile 24.54 ± 4.2%; p &lt;0.0001). LA strain dispersion was also significantly different between the tertiles (61.03 ± 25.8ms vs 41.8 ± 15.8ms vs 44.8 ± 18.8ms; p &lt;0.001). All other clinical and echocardiographic parameters were non-significant between the tertiles however, there was a trend towards a lower PALS in the higher rejection burden group. Kaplan Meier curves demonstrated that survival over follow-up was significantly worse in the lower tertile LA PALS group compared to the highest tertiles LA PALS group (Log-rank test = p &lt; 0.0001). The lowest LA PALS tertile had a significantly higher risk of reaching the primary endpoint compared with patients in the highest LA PALS tertile (hazard ratio [HR] 9.802; 95% CI 1.832-52.45; p &lt;0.008). Higher LA PALS and LV GLS (LA PALS HR 0.610 95% CI 0.401-0.926; p 0.02; LV GLS HR 0.638 95% CI 0.418-0.972; p 0.037) were significantly associated with a reduction in reaching the primary endpoint in a multi-variate regression model including clinically relevant traditional and strain-based echocardiographic parameters.

Conclusions

Lower LA PALS is significantly associated with poorer long-term outcomes in cardiac transplant patients with ACR. Non-invasive LA PALS may be a useful predictor of long-term outcome in patients post cardiac transplantation. Abstract Figure. Survival curves for LA PALS tertiles