We present an improved search for neutrinoless double-beta (0νββ) decay of ^{136}Xe in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a ...significant reduction of the ^{110m}Ag contaminant identified in previous searches. Combining the results from the first and second phase, we obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>1.07×10^{26} yr at 90% C.L., an almost sixfold improvement over previous limits. Using commonly adopted nuclear matrix element calculations, the corresponding upper limits on the effective Majorana neutrino mass are in the range 61-165 meV. For the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.
The Anterior Cruciate Ligament (ACL)-deficient model helps to clarify the mechanism of knee osteoarthritis (OA); however, the conventional ACL injury model could have included concurrent onset ...factors such as direct compression stress to cartilage and subchondral bone. In this study, we established a novel Non-invasive ACL-Ruptured mouse model without concurrent injuries and elucidated the relationship between OA progression and joint instability.
We induced the ACL-Rupture non-invasively in twelve-week-old C57BL/6 male mice and evaluated histological, macroscopical, and morphological analysis at 0 days. Next, we created the ACL-R, controlled abnormal tibial translation (CATT), and Sham groups. Then, the joint stability and OA pathophysiology were analyzed at 2, 4, and 8 weeks.
No intra-articular injuries, except for ACL rupture, were observed in the ACL-R model. ACL-R mice increased anterior tibial displacement compared to the Sham group (P < 0.001, 95% CI −1.509 to −0.966) and CATT group (P < 0.001, 95% CI −0.841 to −0.298) at 8 weeks. All mice in the ACL-R group caused cartilage degeneration. The degree of cartilage degeneration in the ACL-R group was higher than in the CATT group (P = 0.006) at 8 weeks. The MMP-3-positive cell rate of chondrocytes increased in the ACL-R group than CATT group from 4 weeks (P = 0.043; 95% CI −28.32 to −0.364) while that of synovial cells increased at 8 weeks (P = 0.031; 95% CI −23.398 to −1.021).
We successfully established a Non-invasive ACL-R model without intra-articular damage. Our model revealed that chondrocytes might react to abnormal mechanical stress prior to synovial cells while the knee OA onset.
It has been debated whether the onset of knee osteoarthritis is initiated in cartilage or subchondral bone. The purpose of this study was to clarify the effects of increasing or decreasing joint ...instability on cartilage degeneration and subchondral bone changes in knee OA by comparing different models of joint instability.
We used the anterior cruciate ligament transection (ACL-T) model and the destabilization of the medial meniscus (DMM) model. In addition, we created a controlled abnormal tibial translation (CATT) model and a controlled abnormal tibial rotation (CATR) model. We performed joint instability analysis, micro-computed tomography analysis, histological and immunohistological analysis in 4 and 6 weeks.
The CATT group suppressed joint instability in the ACL-T group (6 weeks; P = 0.032), and the CATR group suppressed joint instability in the DMM group (6 weeks; P = 0.032). Chondrocyte hypertrophy in the ACL-T and DMM groups was increased compared to the Sham group (6 weeks; ACL-T vs Sham, P = 0.002, 95%CI 5.983–33.025; DMM vs Sham, P = 0.022, 95%CI 1.691–28.733). In the subchondral bone, the BV/TV in the DMM and CATR groups was increased compared to the ACL-T and CATT groups (6 weeks; DMM vs ACL-T, P = 0.002, 95%CI 7.404–37.582; DMM vs CATT, P = 0.014, 95%CI 2.881–33.059; CATR vs ACL-T, P = 0.006, 95%CI 4.615–34.793; CATR vs CATT, P = 0.048, 95%CI 0.092–30.270).
This study showed that joint instability promotes chondrocyte hypertrophy, but subchondral bone changes were influenced by differences in ACL and meniscus function.
We measured a set of π±Σ∓, π0Σ0, and π−Σ0 invariant mass spectra below and above the K¯N mass threshold in K−-induced reactions on deuteron. The measured πΣ mass spectral shape is well reproduced via ...the two-step mechanism, i.e., a neutron knocked out at a forward angle from a deuteron by an incident K−, with the K¯ recoiled backward reacting with the residual nucleon to produce π and Σ. We deduced the S-wave K¯N→πΣ and K¯N→K¯N scattering amplitudes in the isospin 0 channel in the framework of a K¯N and πΣ coupled channel. We find that a resonance pole corresponding to Λ(1405) is located at 1417.7−7.4+6.0 (fitting errors)−1.0+1.1 (systematic errors) + −26.1−7.9+6.0 (fitting errors)−2.0+1.7 (systematic errors) i MeV/c2, closer to the K¯N mass threshold than the value determined by the Particle Data Group.
In this work we present a keV-scale sterile-neutrino search with a low-tritium-activity data set of the KATRIN experiment, acquired in a commissioning run in 2018. KATRIN performs a spectroscopic ...measurement of the tritium
β
-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the measurement of a wider part of the tritium spectrum and thus the search for sterile neutrinos with a mass of up to
1.6
keV
. We do not find a signal and set an exclusion limit on the sterile-to-active mixing amplitude of
sin
2
θ
<
5
×
10
-
4
(
95
%
C.L.) at a mass of 0.3 keV. This result improves current laboratory-based bounds in the sterile-neutrino mass range between 0.1 and 1.0 keV.
The decay of the primordial isotopes 238U, 235U, 232Th, and 40K has contributed to the terrestrial heat budget throughout the Earth's history. Hence, the individual abundance of those isotopes are ...key parameters in reconstructing contemporary Earth models. The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid‐Scintillator Antineutrino Detector (KamLAND). Those measurements have been improved with more than 18‐year observation time, and improvement in detector background levels mainly with an 8‐year nearly reactor‐free period, which now permit spectroscopy with geoneutrinos. Our results yield the first constraint on both uranium and thorium heat contributions. The KamLAND result is consistent with geochemical estimations based on elemental abundances of chondritic meteorites and mantle peridotites. The High‐Q model is disfavored at 99.76% C.L. and a fully radiogenic model is excluded at 5.2σ assuming a homogeneous heat producing element distribution in the mantle.
Plain Language Summary
The energy to drive the Earth's engine comes from two different sources: primordial and radiogenic. Primordial energy comes from the added heat by collisions of accreting material and less so by the energy accompanying the sinking of metal to form the core. The radioactive decays of heat producing elements (i.e., potassium, thorium, and uranium) also generate energy and some of these decaying elements produce antineutrinos (geoneutrinos). Geoneutrino measurements provide the Earth's fuel gauge for its radiogenic power supply and insights into the planet's cooling history. The measurement accuracy of the KamLAND experiment has been improved by an 18‐year long‐term observation and a reduction of the significant background generated by commercial reactors. Consequently, modern geoneutrino measurements have entered an era of distinct spectroscopic contributions coming from uranium and thorium. The KamLAND result is consistent with compositional models for the bulk silicate Earth (the crust plus the mantle) predicting low to medium radiogenic heat (10–20 TW (1012 W)) and disfavor high concentration models (30 TW). This constraint sets the best limit on the permissible radiogenic energy budget in the Earth. Geoneutrino observations now begin to make significant contributions to the understanding of fundamental driving forces powering the Earth dynamic behavior.
Key Points
Geoneutrino measurement with low reactor neutrino backgrounds improves the distinct spectroscopic contributions of U and Th
Radiogenic power in the Earth estimated from this geoneutrino measurement is consistent with a range of models and disfavors the higher power model
Identifying the Earth's mantle contribution to the total geoneutrino flux strongly depends on an accurate estimation of the crustal contribution
Particle dark matter could belong to a multiplet that includes an electrically charged state. WIMP dark matter (χ0) accompanied by a negatively charged excited state (χ−) with a small mass difference ...(e.g. < 20 MeV) can form a bound-state with a nucleus such as xenon. This bound-state formation is rare and the released energy is O(1−10) MeV depending on the nucleus, making large liquid scintillator detectors suitable for detection. We searched for bound-state formation events with xenon in two experimental phases of the KamLAND-Zen experiment, a xenon-doped liquid scintillator detector. No statistically significant events were observed. For a benchmark parameter set of WIMP mass mχ0=1 TeV and mass difference Δm=17 MeV, we set the most stringent upper limits on the recombination cross section times velocity 〈σv〉 and the decay-width of χ− to 9.2×10−30cm3/s and 8.7×10−14 GeV, respectively at 90% confidence level.
Tumor-suppressor genes on chromosome X can be inactivated by a single hit, any of the point mutations, chromosomal loss and aberrant DNA methylation. As aberrant DNA methylation can be induced ...frequently, we here aimed to identify a tumor-suppressor gene on chromosome X inactivated by promoter DNA methylation. Of 69 genes on chromosome X upregulated by treatment of a gastric cancer cell line with a DNA-demethylating agent, 5-aza-2'-deoxycytidine, 11 genes had low or no expression in the cell line and abundant expression in normal gastric mucosae. Among them, FHL1 was frequently methylation-silenced in gastric and colon cancer cell lines, and methylated in primary gastric (21/80) and colon (5/50) cancers. Knockdown of the endogenous FHL1 in two cell lines by two kinds of shRNAs significantly increased cell growth in vitro and sizes of xenografts in nude mice. Expression of exogenous FHL1 in a non-expressing cell line significantly reduced its migration, invasion and growth. Notably, a somatic mutation (G642T; Lys214Asn) was identified in one of 144 colon cancer specimens, and the mutant FHL1 was shown to lack its inhibitory effects on migration, invasion and growth. FHL1 methylation was associated with Helicobacter pylori infection and accumulated in normal-appearing gastric mucosae of gastric cancer patients. These data showed that FHL1 is a methylation-silenced tumor-suppressor gene on chromosome X in gastrointestinal cancers, and that its silencing contributes to the formation of an epigenetic field for cancerization.
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