Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Combined Analysis of Neutrino and Antineutrino Oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135  μ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66  μ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

Kinetic model-based factor analysis of dynamic sequences for 82-rubidium cardiac positron emission tomography

PURPOSE

Factor analysis has been pursued as a means to decompose dynamic cardiac PET images into different tissue types based on their unique temporal signatures to improve quantification of physiological function. In this work, the authors present a novel kinetic model-based (MB) method that includes physiological models of factor relationships within the decomposition process. The physiological accuracy of MB decomposed (82)Rb cardiac PET images is evaluated using simulated and experimental data. Precision of myocardial blood flow (MBF) measurement is also evaluated.

METHODS

A gamma-variate model was used to describe the transport of (82)Rb in arterial blood from the right to left ventricle, and a one-compartment model to describe the exchange between blood and myocardium. Simulations of canine and rat heart imaging were performed to evaluate parameter estimation errors. Arterial blood sampling in rats and (11)CO blood pool imaging in dogs were used to evaluate factor and structure accuracy. Variable infusion duration studies in canine were used to evaluate MB structure and global MBF reproducibility. All results were compared to a previously published minimal structure overlap (MSO) method.

RESULTS

Canine heart simulations demonstrated that MB has lower root-mean-square error (RMSE) than MSO for both factor (0.2% vs 0.5%, p < 0.001 MB vs MSO, respectively) and structure (3.0% vs 4.7%, p < 0.001) estimations, as with rat heart simulations (factors: 0.2% vs 0.9%, p < 0.001 and structures: 3.0% vs 6.7%, p < 0.001). MB blood factors compared to arterial blood samples in rats had lower RMSE than MSO (1.6% vs 2.2%, p =0.025). There was no difference in the RMSE of blood structures compared to a (11)CO blood pool image in dogs (8.5% vs 8.8%, p =0.23). Myocardial structures were more reproducible with MB than with MSO (RMSE=3.9% vs 6.2%, p < 0.001), as were blood structures (RMSE=4.9% vs 5.6%, p =0.006). Finally, MBF values tended to be more reproducible with MB compared to MSO (CV= 10% vs 18%, p =0.16). The execution time of MB was, on average, 2.4 times shorter than MSO (p < 0.001) due to fewer free parameters.

CONCLUSIONS

Kinetic model-based factor analysis can be used to provide physiologically accurate decomposition of (82)Rb dynamic PET images, and may improve the precision of MBF quantification.

Chromosome aberrations and cell inactivation induced in mammalian cells by ultrasoft X‐rays: correlation with the core ionizations in DNA

PURPOSE

To study the frequency of chromosome aberrations induced by soft X-rays. To see if the core ionization of DNA atoms is involved in this end-point as much as it appears to be in cell killing.

MATERIALS AND METHODS

V79 hamster cells were irradiated by synchrotron radiation photons iso-attenuated in the cell (250, 350, 810eV). The morphological chromosome aberrations detected in the first post-irradiation cell division (dicentrics and centric rings) were studied by Giemsa staining.

RESULTS

The chromosome aberrations at 350eV were, respectively, 2.6 +/- 0.8 and 2.1 +/- 0.8 times more numerous than at 250 and 810eV for the same average dose absorbed by the nucleus. These relative effectivenesses are comparable with the ones already measured for cell killing. Moreover, they roughly vary such as the relative numbers of core ionizations (including in the phosphorus L-shell) produced in DNA and its bound water (water being involved only at 810eV through the oxygen atoms). In particular, they reproduce the characteristic twofold enhancement at 350eV, above the carbon K threshold.

CONCLUSIONS

Correlations suggest that the core ionization process is likely a common and essential mechanism initiating both chromosome aberration and cell killing end-points at these photon energies.

Immunomodulatory effects of probiotics in the intestinal tract

The intestinal microbiota is the largest source of microbial stimulation that exerts both harmful and beneficial effects on human health. The interaction between probiotic and enterocytes is the initiating event in immunomodulation and merits particular attention. The effects of probiotic is strain dependent and for each new probiotic strain, profiles of cytokines secreted by lymphocytes, enterocytes or dendritic cells that come in contact with the strain should be systematically established. To evaluate the effects of probiotics on the immune system, models that mimic the mucosa, and thus the physiological reality, should be preferred whenever it is possible. Then, the in vitro observed effects should be backed up by properly conducted randomized double bind clinical studies. More detailed studies are needed to determine the precise action mode of probiotics on both mucosal and systemic immunity.

Biological effects induced by K photo-ionisation in and near constituent atoms of DNA

In order to assess the lethal efficiency and other biological effects of inner shell ionisations of constituent atoms of DNA ('K' events), experiments were developed at the LURE synchrotron facility using ultrasoft X rays as a probe of K events. The lethal efficiency of ultrasoft X rays above the carbon K threshold was especially investigated using V79 cells and compared with their efficiency to induce double strand breaks in dry plasmid-DNA. A correlation between the K event efficiencies for these processes is shown. Beams at 340 eV were found to be twice as efficient at killing cells than were beams at 250 eV. In addition, a rough two-fold increase of the relative biological effectiveness for dicentric + ring induction has also been observed between 250 and 340 eV radiations.

X-ray emission from a compact hot plasma: applications to radiology and mammography

Hot electrons confined in a compact magnetized plasma (in a 1 litre chamber) and heated by electron cyclotron resonance were used to provide an intense reproducible x-ray emission. Since electrons were generated in situ, the use of filaments and high voltages at the base of the x-ray tubes was avoided. The source can be pulsed or operated in a highly stable continuous mode. The spatial and energetic characteristics of the hot electrons were determined via their bremsstrahlung by comparison with theoretical calculations. In this test x-ray source the average energy of the hot electron flux was in the range 10-40 keV, depending on the operating parameters: intermagnet distance (6-9 cm), power of the 2.45 GHz microwave (200-1000 W), chamber pressure (4 x 10(-5)-9 x 10(-5) Torr). The insertion of solid targets into the electron flux leads to various focal spot sizes, enabling application in radiology and mammography. The images of a mammographic phantom were obtained in a few seconds with good contrast (microcalcifications being successfully detected).

Effect of denture cleansers, surface finish, and temperature on Molloplast B resilient liner color, hardness, and texture

PURPOSE

The purpose of this study was to compare color, texture, and Shore A hardness of a resilient silicone denture liner with as-polymerized, roughened, or pumiced surfaces after treatment with perborate-, persulfate-, or hypochlorite-containing denture cleansers at 25 degrees or 55 degrees.

MATERIALS AND METHODS

Fifty-eight specimens that each exhibited an as-polymerized, a roughened, and a pumiced area were exposed to 5 different commercially available perborate-, persulfate-, or hypochlorite-containing denture cleansers at 25 degrees or 55 degrees continuously for 4 (1/2) months. The solutions were replaced twice a day. Control specimens were soaked in water with no cleanser. Before and after the 4 (1/2) -month cleaning regimen, the color, hardness, and texture of resilient liner surfaces were evaluated using a color densitometer, a Shore A durometer (Shore Instrument & Mfg Co, Freeport, NY), and a surface profilometer, respectively. Differences among groups after the cleanser treatment were determined using a repeated measures analysis of variance (alpha = 0.05) and a Tukey's Honestly Significant Difference post hoc test.

RESULTS

Roughened specimen surfaces after 25 degrees or 55 degrees cleanser treatment exhibited significant color loss with some perborate-containing cleansers compared with the control. Roughened specimens treated at 55 degrees with perborate-containing cleansers also exhibited significantly greater color loss than those treated with the persulfate-containing cleanser. With roughened surfaces, significantly greater hardness was found with some perborate-containing cleanser compared with a hypochlorite-containing cleanser after treatment at 25 degrees. No differences were observed in surface texture based upon cleanser treatment.

CONCLUSION

After silicone resilient denture liner treatment with certain perborate-containing denture cleansers, a greater amount of components could leach from the liner leading to a loss of color if the liner surface is rough.

Bremsstrahlung from thick targets and a diagnostic for electron energy distributions

The bremsstrahlung from solid material caused by runaway electrons may blur severely the bremsstrahlung that is recorded from gases or plasmas in order to determine the energy distribution of their hot electrons. The expressions for these emissions are presented in order to compare their characteristics. Explanations are then given for an irregular feature observed at the tip of the spectrum for solid targets. More importantly, a type of diagnostics of energy distribution functions is proposed, based on analysis of the bremsstrahlung emissivity from thick targets. It can be implemented on experimental setups by purposely inserting a well-defined solid target into the electron trajectories, and it is applied as an example to the electron beam of microwave tubes. These diagnostics could also be taken advantage of to study runaway electrons hitting vessel walls.

Characterization of mesophilic mixed starter cultures used for the manufacture of aged cheddar cheese

Seventy-one different Lactococcus lactis subsp. cremoris strains were isolated from seven mesophilic mixed starters used in the manufacture of aged Cheddar cheese in Canada. Based on plasmid profiles and growth in milk (with or without glucose, Casamino Acids or both), two mixed starters were highly heterogeneous, containing at least 18 to 24 distinct L. lactis strains. Three mixed starters were comprised of seven to nine strains, whereas two starters were relatively homogeneous, containing two or three strains. Many strains with similar plasmid profiles behaved differently during growth in milk, indicating variability in the phenotypes. Only 20% of the strains could grow in plain milk, whereas 30% could not grow in milk supplemented with glucose and Casamino Acids. Twenty-five lactococcal bacteriophages were also isolated from whey samples with single strains as hosts. Eighteen phages belonged to the 936 species and seven to the c2 species. Thirteen strains were insensitive to all 25 phages. Almost all sensitive strains were phage species-specific. The 936-like phages had a broader host range.

Studies on small (<350 microm) alginate-poly-L-lysine microcapsules. III. Biocompatibility Of smaller versus standard microcapsules

Microencapsulation of islets of Langerhans has been proposed as a means of preventing their immune destruction following transplantation. Microcapsules of diameters <350 microm made with an electrostatic pulse system present many advantages relative to standard microcapsules (700-1500 microm), including smaller total implant volume, better insulin kinetics, better cell oxygenation, and accessibility to new implantation sites. To evaluate their biocompatibility, 200, 1000, 1120, 1340, or 3000 of these smaller microcapsules (<350 microm) or 20 standard microcapsules (1247+/-120 microm) were implanted into rat epididymal fat pads, retrieved after 2 weeks, and evaluated histologically. The average pericapsular reaction increased with the number of small microcapsules implanted (p<0.05; 3000 vs. 200, 3000 vs. 1000, and 1000 vs. 200 microcapsules). At equal volume and alginate content, standard microcapsules caused a more intense fibrosis reaction than smaller microcapsules (p<0.05). In addition, 20 standard microcapsules elicited a stronger pericapsular reaction than 200 and 1000 smaller microcapsules (p<0.05) although the latter represented a 3.4-fold larger total implant surface exposed. We conclude that microcapsules of diameters <350 microm made with an electrostatic pulse system are more biocompatible than standard microcapsules.

Detection of Campylobacter jejuni in food and poultry viscera using immunomagnetic separation and microtitre hybridization

Thermophillic Campylobacter and Camp. jejuni were detected from samples of chicken liver, gall bladder, muscle and contaminated milk and chicken meat after an enrichment step by using immunomagnetic capture of cells with monoclonal antibody against a specific outer membrane protein of thermophilic Campylobacter. The detection of captured cells was achieved using two different hybridization methods. In one of the methods, the captured cells were lysed by guanidine isothiocyanate and the 23S rRNA was reacted with a microtitre plate-immobilized rDNA probe specific for thermophilic Campylobacter. In the other method, the captured cells were subjected to lysis by ultrasonication and the genomic DNA reacted with a microtitre plate-immobilized RNA probe specific for Camp.jejuni. Detection of the RNA-DNA hybrids formed in the wells was carried out using a monoclonal anti-RNA-DNA hybrid antibody.

Microtitre plate hybridization system for detection of thermophilic Campylobacter rRNA

A microtitre plate nucleic acid probe hybridization system was developed for the detection of ribosomal RNA from thermophilic Campylobacter (Camp. jejuni, Camp. coli, Camp. lari and Camp. upsaliensis). A specific DNA probe obtained by amplification of 23S rRNA sequences using the polymerase chain reaction technique was immobilized on a microtitre plate, and used for hybridization with target 23S rRNA from cell lysates. The RNA-DNA hybrids thus formed in the wells were detected by an immunoenzymatic assay using a monoclonal antiRNA-DNA hybrid antibody. The sensitivity of this system was 2.7 x 10(4) cells ml(-1). This simple, sensitive and inexpensive hybridization and immunoenzymatic assay system should facilitate the detection of Campylobacter in food and clinical samples.

Microtitre plate riboprobe system for detection of ultrasonicated Campylobacter jejuni genomic DNA

Microtitre plate nucleic acid probe hybridization systems were developed for the detection of thermophilic Campylobacter and Campylobacter jejuni. Specific RNA probes obtained by in vitro transcription of DNA templates synthesized by polymerase chain reaction using two sets of specific primers incorporating bacteriophage T7 promoter sequences were immobilized on a microtitre plate. The hybridizations were carried out on samples of genomic DNA sheared by ultrasonication. Optimum conditions for the ultrasonic treatment were determined in order to obtain the highest degree of hybridization with immobilized RNA probe. Finally, detection of RNA-DNA hybrids in the wells was accomplished by an immunoenzymatic assay using a monoclonal anti-RNA-DNA hybrid antibody. This rapid, simple hybridization and immunoenzymatic assay system will facilitate the detection of Campylobacter in foods and clinical samples.

Structural differences between the free and bound states of the DNA-bisintercalating peptide YSPTSPSY

The YSPTSPSY peptide is a DNA-bisintercalator that can adopt nonrandom conformations in solution. Strategies based on random conformational search and energy minimizations have been applied to generate populations of conformers characterizing YSPTSPSY. Subsequent analysis based on statistical methods and clustering allowed to determine the existence of four classes of conformers containing beta- and/or gamma-turns. NMR spectra of YSPTSPSY in solution provide evidence for such structures. Employing a Monte Carlo-based docking procedure, the YSPTSPSY peptide was docked in a DNA double-helical fragment with the sequence [d(GACGTC)]2. The peptide binds on the minor groove of DNA stacking the central CG base pairs, in a manner similar to that observed in complexes of triostin A with DNA. Upon binding, the structure of the C-terminal segment is modified into a type I beta-turn. Five intermolecular hydrogen bonds are observed, but the van der Waals interactions constitute the major stabilization factor for the complex. NMR chemical shifts, coupling constants, and NOESY connectivities are in agreement with the molecular model.

Recognition of Leuconostoc oenos strains by the use of DNA restriction profiles

The chromosome of 41 Leuconostoc oenos strains obtained from collections in different countries was analysed with the aim of differentiating the strains. Pulsed field electrophoresis (TAFE) was used to separate large DNA fragments created by the restriction enzymes NotI, SfiI and ApaI, which specifically recognize guanines or cytosines. The genomic DNA of 11 strains was analysed initially with NotI and only four different restriction profiles were observed. The genome size ranged from 1.8 to 2.1 megabase pairs (Mbp). Constant field electrophoresis applied to DNA treatment with 19 different restriction enzymes showed that the size of the fragments obtained increased proportionally to the percentage G + C present at the site of restriction. EcoRI and HindIII profiles revealed that the zone between 9 and 23 kbp allowed differentiation of the strains tested. Thus, the 41 strains fell into 30 restriction groups using only two enzymes. Hybridization with a non-radioactive DNA probe coding for 16S rRNA revealed that there were two 16S genes on the chromosome.

Language in right-handers with right-hemisphere lesions: a preliminary study including anatomical, genetic, and social factors

A comprehensive test battery was devised to study the effects of right hemisphere lesions on the speech and language of "nonaphasic" dextrals. Data were thus obtained for 62 subjects, 20 of them neurologically healthy and 42 with a focal right hemisphere lesion resulting from a cerebro-vascular accident. A preliminary global analysis of these data is reported. Anomalies were observed in 33 brain-damaged subjects. Although discreet in all cases, these anomalies were shown to have various degrees of severity. Given the population submitted to this study, the subject most likely to show such anomalies was defined, genetically, as a right-handed adult with a family history of ambidextrality or left-handedness and, socially, as one with a relatively limited education. The implications of these findings are discussed together with the problem of the anatomo-clinical correlations of language disorders resulting from right hemisphere lesions in "nonaphasic" dextrals.

Principal component analysis of four health indicators and construction of a global health index in the aged

The health status of 1025 urban senior citizens in a Montreal metropolitan area was determined by a questionnaire based on the subjects' view of physical, mental, and general well-being, and of dependence (indicators of Belloc et al., Berkman, Grogono and Woodgate, and Linn). A principal component analysis was made of these health indicators and two factors were retained. The first factor, which can be called a global health index, was used to compare the sexes and the age strata; it was thus found that men (those who survive) are generally healthier than the women, and that subjects from the lower-age strata are healthier than their older counterparts. The second factor is described as opposing physical health and dependence to mental health, the results of which were similar for both sexes, bur differed according to the various age strata compared.

[Relationship between some health indicators of physical, mental well-being and handicaps in the aged (author's transl)]

The health status of 1,025 senior urban citizens was determined by a questionnaire based on the subjects' view of physical, mental and global well-being and of dependency (indicators of Belloc and all., Berkman, Grogono and Woodgate, Linn). The significant correlation was observed between different health indicators. However, these correlations are not strong enough to allow the explanation of one indicator by the others. The mental well-being is most independent of all other health measurements under study. The valuable information on the prevalence of some health limitations in the population is given by the constituents of the health indexes used. On the contrary, a more complete view of the health of the population should be obtained by the non correlated methods of measurement. The situation may vary following the epidemiological characteristics of the population studied.