Search for New Physics in Electronic Recoil Data from XENONnT

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to (15.8±1.3)  events/(ton×year×keV), the lowest ever achieved in a dark matter detector and ∼5 times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

Material radiopurity control in the XENONnT experiment

The selection of low-radioactive construction materials is of the utmost importance for rare-event searches and thus critical to the XENONnT experiment. Results of an extensive radioassay program are reported, in which material samples have been screened with gamma-ray spectroscopy, mass spectrometry, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn emanation measurements. Furthermore, the cleanliness procedures applied to remove or mitigate surface contamination of detector materials are described. Screening results, used as inputs for a XENONnT Monte Carlo simulation, predict a reduction of materials background (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼17%) with respect to its predecessor XENON1T. Through radon emanation measurements, the expected \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn activity concentration in XENONnT is determined to be 4.2 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{+0.5}_{-0.7}$$\end{document}-0.7+0.5) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu $$\end{document}μBq/kg, a factor three lower with respect to XENON1T. This radon concentration will be further suppressed by means of the novel radon distillation system.

Probing local chromatin dynamics by tracking telomeres

Chromatin dynamics is key for cell viability and replication. In interphase, chromatin is decondensed, allowing the transcription machinery to access a plethora of DNA loci. Yet, decondensed chromatin occupies almost the entire nucleus, suggesting that DNA molecules can hardly move. Recent reports have even indicated that interphase chromatin behaves like a solid body on mesoscopic scales. To explore the local chromatin dynamics, we have performed single-particle tracking on telomeres under varying conditions. We find that mobile telomeres feature in all conditions a strongly subdiffusive, anti-persistent motion that is consistent with the monomer motion of a Rouse polymer in viscoelastic media. In addition, telomere trajectories show intermittent accumulations in local niches at physiological conditions, suggesting the surrounding chromatin to reorganize on these time scales. Reducing the temperature or exposing cells to osmotic stress resulted in a significant reduction of mobile telomeres and the number of visited niches. Altogether, our data indicate a vivid local chromatin dynamics, akin to a semi-dilute polymer solution, unless perturbations enforce a more rigid or entangled state of chromatin.

Conduction system pacing in paediatric patients: a single centre experience

Funding Acknowledgements

Type of funding sources: None.

Background

Paediatric patients with conduction abnormalities are generally exposed to life-long dyssynchronous pacing from a very early age. Thus, preservation of cardiac function during chronic ventricular pacing is important. Conduction system pacing (CSP) with His bundle pacing (HBP) or left bundle branch pacing (LBBP) is an alternative method to standard right ventricular (RV) pacing that may preserve physiological ventricular activation and avoid potential pacing-induced cardiomyopathy (1). However, data on feasibility and safety of various CSP approaches in paediatric patients with or without congenital heart disease (CHD) is scarce and mainly relies on case studies (2-4).

Purpose

To assess feasibility and outcomes of different CSP techniques in paediatric patients.

Methods

Consecutive paediatric patients in whom CSP was attempted in our centre between November 2019 and December 2021 were analysed. Acute implant success rate, complications, fluoroscopy times, and CSP pacing parameters during follow-up were assessed.

To reduce radiation exposure, minimal fluoroscopy technique with three-dimensional (3D) electro-anatomical mapping (EAM) was also used in some cases. Geometry of right atrium and RV, along with mapping of His signal for HBP and potential LBBP sites in the RV septum were created using a decapolar catheter from the right femoral vein. Once relevant anatomy was obtained, HBP or LBBP was attempted using commercially available CSP tools. The pacing lead tip was visualised using the 3D EAM system. Transient fluoroscopy was used only for perpendicular placement of the sheath to the RV septum during LBBP, sheath removal, lead loop assessment to allow linear growth, and atrial lead placement.

Results

Six patients (100% female, age 9.3 ± 3.9 years, weight 41.8 ± 22.9 kg, baseline QRS 111.5 ± 6.3ms, CHD 50%, previous device 33%) with congenital complete AV block received CSP. One patient received HBP and 5 LBBP. The procedure was acutely successful in all patients (100%), pacing thresholds were low (0.56 ± 0.18V at 0.5ms) and there were no perioperative complications. During mean follow-up of 11.8 ± 7.8 months pacing parameters remained stable. However, significant rise of the pacing threshold (> 2.5V) was registered in the HBP patient, in whom lead revision was performed. Three-dimensional EAM was utilised in 3 patients (1 HBP, 2 LBBP). The use of minimal fluoroscopy technique with 3D EAM reduced fluoroscopy time (4.0, 3.2, 4.5 min vs. 9.5, 11.0, 8.0 min) without increasing procedural time (80, 70, 50 min vs. 110, 60, 75 min) compared to standard fluoroscopy technique.

Conclusion

Conduction system pacing is feasible and safe in paediatric patients with or without CHD. Additional utilisation of 3D EAM could reduce radiation exposure, without increasing procedural time. Future long-term studies should be considered to provide the ground for wider clinical adoption of CSP in paediatric population.

Examining allostatic load, neighborhood socioeconomic status, symptom burden and mortality in multiple myeloma patients

The objective of this study is to examine the association between neighborhood socioeconomic status (nSES) and baseline allostatic load (AL) and clinical trial endpoints in patients enrolled in the E1A11 therapeutic trial in multiple myeloma (MM). Study endpoints were symptom burden (pain, fatigue, and bother) at baseline and 5.5 months, non-completion of induction therapy, overall survival (OS) and progression-free survival (PFS). Multivariable logistic and Cox regression examined associations between nSES, AL and patient outcomes. A 1-unit increase in baseline AL was associated with greater odds of high fatigue at baseline (adjusted OR [95% CI] = 1.21 [1.08–1.36]) and a worse OS (adjusted hazard ratio, [95% CI] = 1.21 [1.06–1.37]). High nSES was associated with worse baseline bother (middle OR = 4.22 [1.11–16.09] and high 4.49 [1.16–17.43]) compared to low nSES. There was no association between AL or nSES and symptom burden at 5.5 months, non-completion of induction therapy or PFS. Additionally, there was no association between nSES and OS. AL may have utility as a predictive marker for OS among patients with MM and may allow individualization of treatment. Future studies should standardize and validate AL patients with MM.

Patients recently treated for B-lymphoid malignancies show increased risk of severe COVID-19: a CCC19 registry analysis

Patients with B-lymphoid malignancies have been consistently identified as a population at high risk of severe COVID-19. Whether this is exclusively due to cancer-related deficits in humoral and cellular immunity, or whether risk of severe COVID-19 is increased by anti-cancer therapy, is uncertain. Using data derived from the COVID-19 and Cancer Consortium (CCC19), we show that patients treated for B-lymphoid malignancies have an increased risk of severe COVID-19 compared to control populations of patients with non-B-lymphoid hematologic malignancies. Among patients with B-lymphoid malignancies, those who received anti-cancer therapy within 12 months of COVID-19 diagnosis experienced increased COVID-19 severity compared to patients with B-lymphoid malignancies off therapy, after adjustment for cancer status and several other prognostic factors. Our findings suggest that patients recently treated for a B-lymphoid malignancy are at uniquely high risk for severe COVID-19.

Outcomes on anti-VEGFR-2/paclitaxel treatment after progression on immune checkpoint inhibition in patients with metastatic gastroesophageal adenocarcinoma

Through our involvement in KEYNOTE-059, we unexpectedly observed durable responses in two patients with metastatic gastroesophageal adenocarcinoma (mGEA) who received ramucirumab (anti-VEGFR-2)/paclitaxel after immune checkpoint inhibition (ICI). To assess the reproducibility of this observation, we piloted an approach to administer ramucirumab/paclitaxel after ICI in more patients, and explored changes in the immune microenvironment. Nineteen consecutive patients with mGEA received ICI followed by ramucirumab/paclitaxel. Most (95%) did not respond to ICI, yet after irRECIST-defined progression on ICI, all patients experienced tumor size reduction on ramucirumab/paclitaxel. The objective response rate (ORR) and progression-free survival (PFS) on ramucirumab/paclitaxel after ICI were higher than on the last chemotherapy before ICI in the same group of patients (ORR, 58.8% vs 11.8%; PFS 12.2 vs 3.0 months; respectively). Paired tumor biopsies examined by imaging mass cytometry showed a median 5.5-fold (range 4-121) lower frequency of immunosuppressive forkhead box P3+ regulatory T cells with relatively preserved CD8+ T cells, post-treatment versus pre-treatment (n = 5 pairs). We then compared the outcomes of these 19 patients with a separate group who received ramucirumab/paclitaxel without preceding ICI (n = 68). Median overall survival on ramucirumab/paclitaxel was longer with (vs without) immediately preceding ICI (14.8 vs 7.4 months) including after multivariate analysis, as was PFS. In our small clinical series, outcomes appeared improved on anti-VEGFR-2/paclitaxel treatment when preceded by ICI, in association with alterations in the immune microenvironment. However, further investigation is needed to determine the generalizability of these data. Prospective clinical trials to evaluate sequential treatment with ICI followed by anti-VEGF(R)/taxane are underway.

Single-Particle Tracking Reveals Anti-Persistent Subdiffusion in Cell Extracts

Single-particle tracking (SPT) has become a powerful tool to quantify transport phenomena in complex media with unprecedented detail. Based on the reconstruction of individual trajectories, a wealth of informative measures become available for each particle, allowing for a detailed comparison with theoretical predictions. While SPT has been used frequently to explore diffusive transport in artificial fluids and inside living cells, intermediate systems, i.e., biochemically active cell extracts, have been studied only sparsely. Extracts derived from the eggs of the clawfrog Xenopus laevis, for example, are known for their ability to support and mimic vital processes of cells, emphasizing the need to explore also the transport phenomena of nano-sized particles in such extracts. Here, we have performed extensive SPT on beads with 20 nm radius in native and chemically treated Xenopus extracts. By analyzing a variety of distinct measures, we show that these beads feature an anti-persistent subdiffusion that is consistent with fractional Brownian motion. Chemical treatments did not grossly alter this finding, suggesting that the high degree of macromolecular crowding in Xenopus extracts equips the fluid with a viscoelastic modulus, hence enforcing particles to perform random walks with a significant anti-persistent memory kernel.

Association of clinical factors and recent anticancer therapy with COVID-19 severity among patients with cancer: a report from the COVID-19 and Cancer Consortium

BACKGROUND

Patients with cancer may be at high risk of adverse outcomes from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We analyzed a cohort of patients with cancer and coronavirus 2019 (COVID-19) reported to the COVID-19 and Cancer Consortium (CCC19) to identify prognostic clinical factors, including laboratory measurements and anticancer therapies.

PATIENTS AND METHODS

Patients with active or historical cancer and a laboratory-confirmed SARS-CoV-2 diagnosis recorded between 17 March and 18 November 2020 were included. The primary outcome was COVID-19 severity measured on an ordinal scale (uncomplicated, hospitalized, admitted to intensive care unit, mechanically ventilated, died within 30 days). Multivariable regression models included demographics, cancer status, anticancer therapy and timing, COVID-19-directed therapies, and laboratory measurements (among hospitalized patients).

RESULTS

A total of 4966 patients were included (median age 66 years, 51% female, 50% non-Hispanic white); 2872 (58%) were hospitalized and 695 (14%) died; 61% had cancer that was present, diagnosed, or treated within the year prior to COVID-19 diagnosis. Older age, male sex, obesity, cardiovascular and pulmonary comorbidities, renal disease, diabetes mellitus, non-Hispanic black race, Hispanic ethnicity, worse Eastern Cooperative Oncology Group performance status, recent cytotoxic chemotherapy, and hematologic malignancy were associated with higher COVID-19 severity. Among hospitalized patients, low or high absolute lymphocyte count; high absolute neutrophil count; low platelet count; abnormal creatinine; troponin; lactate dehydrogenase; and C-reactive protein were associated with higher COVID-19 severity. Patients diagnosed early in the COVID-19 pandemic (January-April 2020) had worse outcomes than those diagnosed later. Specific anticancer therapies (e.g. R-CHOP, platinum combined with etoposide, and DNA methyltransferase inhibitors) were associated with high 30-day all-cause mortality.

CONCLUSIONS

Clinical factors (e.g. older age, hematological malignancy, recent chemotherapy) and laboratory measurements were associated with poor outcomes among patients with cancer and COVID-19. Although further studies are needed, caution may be required in utilizing particular anticancer therapies.

CLINICAL TRIAL IDENTIFIER

NCT04354701.

ECOG-ACRIN EAA181: Effective quadruplet utilization after treatment evaluation (EQUATE)—a randomized phase 3 trial for newly diagnosed multiple myeloma (NDMM) not intended for early autologous transplantation

TPS8052

Background: The monoclonal antibody (MoAb) daratumumab (dara) has been approved for treatment of newly diagnosed Multiple Myeloma (NDMM) in combination with lenalidomide (len) and dexamethasone (DRd) in patients who are not eligible to undergo stem cell transplantation (SCT). Ongoing trials are examining the role of adding bortezomib (Btz) to DRd, but it remains unclear if all patients benefit from a quadruplet regimen. Availability of sensitive assays to detect measurable/minimal residual disease (MRD) in MM and emerging data demonstrating significant prognostic value for attaining MRD negativity, offers an unprecedented opportunity to develop individualized treatment approaches. An important question is to identify who benefits from adding a fourth drug to the MoAb-IMiD triplet, thus individualizing therapy based on depth of response. We hypothesize that prolonged intensive therapy with the addition of Btz for consolidation and maintenance after DRd induction therapy for NDMM will improve survival outcomes with a more pronounced effect when used in MRD positive patients. Methods: Patients with NDMM, R-ISS Stage I or II, who are not eligible to undergo SCT or those willing to defer SCT to first relapse and have not received more than 1 cycle of any NDMM therapy will be enrolled, provided they have measurable disease, adequate organ and marrow function, have received no more than once cycle of therapy for MM and significant peripheral neuropathy or chronic obstructive pulmonary disease. Importantly, a dominant clone should be identified by lymphotrack assay for future MRD monitoring. Once enrolled, induction therapy will be in 28 day cycles consisting of daraSC (1800 mg) weekly for 2 cycles, every other week for cycles 3-6 and then every 4 weeks for 9 cycles, along with len 25 mg days 1-21 of each cycle and dex 40 mg (20 mg for those > 75 years) weekly. At end of 9 cycles (induction), patients will undergo MRD testing by next generation sequencing and will be classified into MRD positive or negative subgroups. Using MRD as an integral biomarker, the trial employs a randomized biomarker-stratified design as proposed by Freidlin et al. to determine efficacy for each MRD subgroup. Patients will be stratified by MRD status and R-ISS stage and randomized to receive 9 cycles of consolidation with DRd, without (control arm) or with (experimental arm) Btz (1.3 mg/m2 weekly for 3 of 4 weeks), followed by DR maintenance until progression The primary endpoint is consolidation OS. Sample size considerations rest on estimates of MRD subgroup prevalence at the end of induction and operating characteristics establishing the treatment effect within the MRD positive subgroup as primary and MRD negative subgroup as key secondary. The total accrual goal is 1450 patients. Clinical trial information: NCT04566328.

Unscrambling exit site patterns on the endoplasmic reticulum as a quenched demixing process

The endoplasmic reticulum (ER) is a vital organelle in mammalian cells with a complex morphology. Consisting of sheet-like cisternae in the cell center, the peripheral ER forms a vast tubular network on which a dispersed pattern of a few hundred specialized domains (ER exit sites (ERESs)) is maintained. Molecular details of cargo sorting and vesicle formation at individual ERESs, fueling the early secretory pathway, have been studied in some detail. The emergence of spatially extended ERES patterns, however, has remained poorly understood. Here, we show that these patterns are determined by the underlying ER morphology, suggesting ERESs to emerge from a demixing process that is quenched by the ER network topology. In particular, we observed fewer but larger ERESs when transforming the ER network to more sheet-like morphologies. In contrast, little to no changes with respect to native ERES patterns were observed when fragmenting the ER, indicating that hampering the diffusion-mediated coarse graining of domains is key for native ERES patterns. Model simulations support the notion of effective diffusion barriers impeding the coarse graining and maturation of ERES patterns. We speculate that tuning a simple demixing mechanism by the ER topology allows for a robust but flexible adaption of ERES patterns, ensuring a properly working early secretory pathway in a variety of conditions.

222 Rn emanation measurements for the XENON1T experiment

The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the 222 Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a 222 Rn activity concentration of 10 μ Bq / kg in 3.2 t of xenon. The knowledge of the distribution of the 222 Rn sources allowed us to selectively eliminate problematic components in the course of the experiment. The predictions from the emanation measurements were compared to data of the 222 Rn activity concentration in XENON1T. The final 222 Rn activity concentration of ( 4.5 ± 0.1 ) μ Bq / kg in the target of XENON1T is the lowest ever achieved in a xenon dark matter experiment.

Search for Coherent Elastic Scattering of Solar ^{8}B Neutrinos in the XENON1T Dark Matter Experiment

We report on a search for nuclear recoil signals from solar ^{8}B neutrinos elastically scattering off xenon nuclei in XENON1T data, lowering the energy threshold from 2.6 to 1.6  keV. We develop a variety of novel techniques to limit the resulting increase in backgrounds near the threshold. No significant ^{8}B neutrinolike excess is found in an exposure of 0.6  t×y. For the first time, we use the nondetection of solar neutrinos to constrain the light yield from 1-2 keV nuclear recoils in liquid xenon, as well as nonstandard neutrino-quark interactions. Finally, we improve upon world-leading constraints on dark matter-nucleus interactions for dark matter masses between 3 and 11  GeV c^{-2} by as much as an order of magnitude.

Quantifying active diffusion in an agitated fluid

Mixing of reactants in microdroplets predominantly relies on diffusional motion due to small Reynolds numbers and the resulting absence of turbulent flows. Enhancing diffusion in microdroplets by an auxiliary noise source is therefore a topical problem. Here we report on how the diffusional motion of tracer beads is enhanced upon agitating the surrounding aqueous fluid with miniaturized magnetic stir bars that are compatible with microdroplets and microfluidic devices. Using single-particle tracking, we demonstrate via a broad palette of measures that local stirring of the fluid at different frequencies leads to an enhanced but apparently normal and homogenous diffusion process, i.e. diffusional steps follow the anticipated Gaussian distribution and no ballistic motion is observed whereas diffusion coefficients are significantly increased. The signature of stirring is, however, visible in the power-spectral density and in the velocity autocorrelation function of trajectories. Our data therefore demonstrate that diffusive mixing can be locally enhanced with miniaturized stir bars while only moderately affecting the ambient noise properties. The latter may also facilitate the controlled addition of nonequilibrium noise to complex fluids in future applications.