Constraints on Axionlike Particles from a Hard X-Ray Observation of Betelgeuse.

We use the first observation of Betelgeuse in hard x rays to perform a novel search for axionlike particles (ALPs). Betelgeuse is not expected to be a standard source of x rays, but light ALPs produced in the stellar core could be converted back into photons in the Galactic magnetic field, producing a detectable flux that peaks in the hard x-ray band (E_{γ}>10 keV). Using a 50 ks observation of Betelgeuse by the NuSTAR satellite telescope, we find no significant excess of events above the expected background. Using models of the regular Galactic magnetic field in the direction of Betelgeuse, we set a 95% C.L. upper limit on the ALP-photon coupling of g_{aγ}<(0.5-1.8)×10^{-11} GeV^{-1} (depending on magnetic field model) for ALP masses m_{a}<(5.5-3.5)×10^{-11} eV.

Expression profile of Fc receptor-like molecules in patients with IgA nephropathy.

BACKGROUND: Fc receptor-like (FCRL) molecules were considered to play a role in the pathogenesis of certain autoimmune diseases. Nonetheless, the clinical significance of FCRLs in IgA nephropathy (IgAN) remains unclear. OBJECTIVE: This study is aimed at investigating the expression levels of FCRLs molecules in IgAN patients and determining its relevance to disease activity. METHODS: The mRNA expression levels of FCRLs were determined in peripheral blood mononuclear cells (PBMCs) of 42 IgAN patients and 48 healthy controls by quantitative real-time PCR (qRT-PCR). FCRLs proteins expression in B cells of 25 IgAN patients, 14 patients with non-IgAN glomerulonephritis, and 29 healthy controls were detected by Flow cytometry. The Spearman correlation test was used to assess the correlation of FCRLs expression with clinical parameters of IgAN patients. RESULTS: Our results indicated significant down-regulation of FCRL2 and FCRL3 mRNA levels in IgAN patients compared to healthy subjects. Surface protein expression of FCRLs molecules confirmed the qRT-PCR results. But FCRL2 and FCRL3 protein levels did not correlate with clinicopathologic phenotypes of IgAN patients. However, we found a significant positively correlation of FCRL2 and FCRL3 mRNA expression with the core 1 ß1,3-galactosyltransferase (C1GALT1) and its molecular chaperone (Cosmc) mRNA levels in IgAN patients. CONCLUSIONS: FCRL2 and FCRL3 expression levels in IgAN patients are significantly decreased and correlated with CIGALT1 and Cosmc mRNA expression.

Serum lipoprotein(a) and risk of mortality in patients on peritoneal dialysis.

BACKGROUND: Elevated serum lipoprotein(a) [Lp(a)] level is an independent risk factor for atherosclerotic diseases in the general population and hemodialysis patients. However, the association between Lp(a) levels and mortality has received little attention in peritoneal dialysis (PD) patients. OBJECTIVE: The objective of the study was to evaluate the association of Lp(a) levels with all-cause and cardiovascular (CV) mortality in PD patients. METHODS: This retrospective cohort study was conducted in PD patients enrolled from January 1, 2006 to December 31, 2015, and followed until December 31, 2018. Cox regression models were performed to assess the association of serum Lp(a) levels with all-cause and CV mortality in PD patients. RESULTS: In total, 1492 incident PD patients were eligible for the study. During a median follow-up period of 45.1 months, 402 all-cause and 210 CV deaths occurred. Multivariate Cox regression analysis revealed that the first and third tertiles of Lp(a) levels were significantly associated with increased risk for all-cause mortality [hazard ratio (HR) = 1.33, 95% confidence interval (95% CI) = 1.01-1.75, P = .041; HR = 1.53, 95% CI = 1.18-1.98, P = .001, respectively] when compared with the second tertile, and the third tertile of Lp(a) level was independently associated with an 80% increased risk of CV mortality (HR = 1.80, 95% CI = 1.26-2.56, P = .001). Moreover, our results showed that the HRs per log unit higher Lp(a) level for all-cause and CV mortality were 1.53 (95% CI = 1.05-2.22, P = .027) and 2.41 (95% CI = 1.44-4.03, P < .001), respectively. CONCLUSIONS: Our results suggest that both low and high serum Lp(a) levels are risk markers for all-cause death, but only a higher baseline serum Lp(a) level is an independent risk factor for CV mortality in PD patients.

Constraining Dark Matter Models with a Light Mediator at the PandaX-II Experiment.

We search for nuclear recoil signals of dark matter models with a light mediator in PandaX-II, a direct detection experiment in the China Jinping underground laboratory. Using data collected in 2016 and 2017 runs, corresponding to a total exposure of 54 ton day, we set upper limits on the zero-momentum dark matter-nucleon cross section. These limits have a strong dependence on the mediator mass when it is comparable to or below the typical momentum transfer. We apply our results to constrain self-interacting dark matter models with a light mediator mixing with standard model particles, and set strong limits on the model parameter space for the dark matter mass ranging from 5 GeV to 10 TeV.

Limits on Axion Couplings from the First 80 Days of Data of the PandaX-II Experiment.

We report new searches for solar axions and galactic axionlike dark matter particles, using the first low-background data from the PandaX-II experiment at China Jinping Underground Laboratory, corresponding to a total exposure of about 2.7×10^{4} kg day. No solar axion or galactic axionlike dark matter particle candidate has been identified. The upper limit on the axion-electron coupling (g_{Ae}) from the solar flux is found to be about 4.35×10^{-12} in the mass range from 10^{-5} to 1 keV/c^{2} with 90% confidence level, similar to the recent LUX result. We also report a new best limit from the ^{57}Fe deexcitation. On the other hand, the upper limit from the galactic axions is on the order of 10^{-13} in the mass range from 1 to 10 keV/c^{2} with 90% confidence level, slightly improved compared with the LUX.

Dark Matter Results from 54-Ton-Day Exposure of PandaX-II Experiment.

We report a new search for weakly interacting massive particles (WIMPs) using the combined low background data sets acquired in 2016 and 2017 from the PandaX-II experiment in China. The latest data set contains a new exposure of 77.1 live days, with the background reduced to a level of 0.8×10^{-3} evt/kg/day, improved by a factor of 2.5 in comparison to the previous run in 2016. No excess events are found above the expected background. With a total exposure of 5.4×10^{4} kg day, the most stringent upper limit on the spin-independent WIMP-nucleon cross section is set for a WIMP with mass larger than 100 GeV/c^{2}, with the lowest 90% C.L. exclusion at 8.6×10^{-47} cm^{2} at 40 GeV/c^{2}.

Spin-Dependent Weakly-Interacting-Massive-Particle-Nucleon Cross Section Limits from First Data of PandaX-II Experiment.

New constraints are presented on the spin-dependent weakly-interacting-massive-particle–- (WIMP-)nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10^{4} kg day. Assuming a standard axial-vector spin-dependent WIMP interaction with ^{129}Xe and ^{131}Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c^{2} are set in all dark matter direct detection experiments. The minimum upper limit of 4.1×10^{-41} cm^{2} at 90% confidence level is obtained for a WIMP mass of 40 GeV/c^{2}. This represents more than a factor of 2 improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

Dark Matter Results from First 98.7 Days of Data from the PandaX-II Experiment.

We report the weakly interacting massive particle (WIMP) dark matter search results using the first physics-run data of the PandaX-II 500 kg liquid xenon dual-phase time-projection chamber, operating at the China JinPing underground laboratory. No dark matter candidate is identified above background. In combination with the data set during the commissioning run, with a total exposure of 3.3×10^{4} kg day, the most stringent limit to the spin-independent interaction between the ordinary and WIMP dark matter is set for a range of dark matter mass between 5 and 1000 GeV/c^{2}. The best upper limit on the scattering cross section is found 2.5×10^{-46} cm^{2} for the WIMP mass 40 GeV/c^{2} at 90% confidence level.