Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

More improvement than progression of liver fibrosis following antiretroviral therapy in a longitudinal cohort of HIV-infected patients with or without HBV and HCV co-infections

We examined the effect of combination antiretroviral therapy (cART) on liver fibrosis among HIV-infected patients with or without hepatitis B (HBV) or C virus (HCV) co-infection. This was a retrospective cohort study of HIV-infected patients receiving cART during 2004-2016. Liver fibrosis was assessed using Fibrosis-4 (FIB-4) score with three classifications: Class 1, <1.45; Class 2, 1.45-3.25; Class 3, >3.25. Of 3900 participants, 68.6% were HIV mono-infected, 5.3% were HIV/HBV co-infected, 23.8% were HIV/HCV co-infected and 2.3% were HIV/HBV/HCV co-infected. Participants received follow-up treatment (median was 3.3 years). Improvement to a lower class was observed in Class 2 (52.6%) and Class 3 (74.2%), respectively. Progression to a higher class was observed in 12.8% and 5.0% in Class 1 and Class 2, respectively, and with a median time of 5.7 months. For improvement to lower classes, older age, male, Dai ethnicity, injection drug use, HCV co-infection and tenofovir for treatment were negative predictors, but in Class 3 of FIB-4 and time-updated increases in CD4 count from baseline were positive predictors. For progression to higher classes, older age, male, Jingpo ethnicity and HCV co-infection were positive predictors, while baseline CD4 count and in Class 2 of FIB-4 were negative predictors. Improvement to lower class linked with decreased mortality risk among patients in Class 3. Early cART initiation for HIV-infected patients with and without hepatitis co-infections may mitigate or slow down some of liver fibrosis, but special attention should be given to those who are older, male, co-infected with HCV.

Noninvasive Assessment of IDH Mutational Status in World Health Organization Grade II and III Astrocytomas Using DWI and DSC-PWI Combined with Conventional MR Imaging

BACKGROUND AND PURPOSE

Isocitrate dehydrogenase (IDH) has been shown to have both diagnostic and prognostic implications in gliomas. The purpose of this study was to examine whether DWI and DSC-PWI combined with conventional MR imaging could noninvasively predict IDH mutational status in World Health Organization grade II and III astrocytomas.

MATERIALS AND METHODS

We retrospectively reviewed DWI, DSC-PWI, and conventional MR imaging in 42 patients with World Health Organization grade II and III astrocytomas. Minimum ADC, relative ADC, and relative maximum CBV values were compared between IDH-mutant and wild-type tumors by using the Mann-Whitney U test. Receiver operating characteristic curve and logistic regression were used to assess their diagnostic performances.

RESULTS

Minimum ADC and relative ADC were significantly higher in IDH-mutated grade II and III astrocytomas than in IDH wild-type tumors (P < .05). Minimum ADC with the cutoff value of ≥1.01 × 10^-3 mm²/s could differentiate the mutational status with a sensitivity, specificity, positive predictive value, and negative predictive value of 76.9%, 82.6%, 91.2%, and 60.5%, respectively. The threshold value of <2.35 for relative maximum CBV in the prediction of IDH mutation provided a sensitivity, specificity, positive predictive value, and negative predictive value of 100.0%, 60.9%, 85.6%, and 100.0%, respectively. A combination of DWI, DSC-PWI, and conventional MR imaging for the identification of IDH mutations resulted in a sensitivity, specificity, positive predictive value, and negative predictive value of 92.3%, 91.3%, 96.1%, and 83.6%.

CONCLUSIONS

A combination of conventional MR imaging, DWI, and DSC-PWI techniques produces a high sensitivity, specificity, positive predictive value, and negative predictive value for predicting IDH mutations in grade II and III astrocytomas. The strategy of using advanced, semiquantitative MR imaging techniques may provide an important, noninvasive, surrogate marker that should be studied further in larger, prospective trials.

Protection of resveratrol on acute kidney injury in septic rats

AIM

The aim of the study is to investigate protective effect of resveratrol (Res) on acute kidney injury (AKI) in sepsis.

METHODS

Rats in sham group received sham operation; in sham + Res received sham operation and Res (3 mg/kg); in cecal ligation and puncture (CLP) established as sepsis; in CLP + Res (3 mg/kg) with sepsis and Res (3 mg/kg); and in CLP + Res (10 mg/kg) with sepsis and Res (10 mg/kg). Survival rate, serum indexes, inflammatory factors, NF-κB-P65, and SIRT1 were detected. Lipopolysaccharide (LPS) mesangial cell was with Res and SIRT1 silencing.

RESULTS

(1) Res intervention improved survival rate of CLP rat. (2) Compared to sham, serum creatinine, blood urine nitrogen, serum cystatin C, neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, tumor necrosis factor-α, interleukin-1β, IL-6, and renal injury index increased in CLP group, while decreased in CLP + Res (3 mg/kg) and CLP + Res (10 mg/kg), significantly, as dose-dependent ( p < 0.05). (3) With Res, NF-κB-P65 and de-acetylated SIRT1 decreased, while SIRT1 and de-acetylated Nuclear factor kB-p65 9 NF-κB-P65) increased, significantly ( p < 0.05). (4) SIRT1 and de-acetylated NF-κB-P65 decreased in LPS cells, while SIRT1 increased after Res intervention, significantly ( p < 0.05). After silencing SIRT1, de-acetylated NF-κB-P65 increased, significantly ( p < 0.05).

CONCLUSIONS

Res increases the survival rate of septic rats by inhibiting inflammatory factors to ease AKI and promotes NF-κB-P65 de-acetylation by upregulating SIRT1.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

Buccally impacted maxillary canines increase the likelihood of root separation in adjacent first premolars

OBJECTIVE

To investigate the influence of maxillary impacted canines on the root morphology of adjacent premolars in a Chinese population.

SUBJECTS AND METHODS

A sample of 370 Chinese subjects with maxillary canine impaction and 370 control subjects were collected in this study. CBCT data of all subjects were collected and analyzed. The prevalence of separate-rooted maxillary premolars was compared between subjects with and without impacted canines. Then, the prevalence of separate-rooted maxillary premolars was compared between subjects with buccal canine impaction (BIC) and those with palatal impaction (PIC).

RESULTS

The prevalence of separate-rooted first premolars was significantly higher in the canine impaction group (P = 0.046), but the prevalence of separate-rooted second premolars was not different (P = 0.780). Furthermore, a significant higher prevalence of first premolar root separation was found on the impacted site in the BIC subgroup (P < 0.001), but not in the PIC subgroup (P = 0.508). Also, the prevalence of separate-rooted first premolars in the BIC subgroup was significantly higher than that of the control group (P = 0.008), but not so for the PIC subgroup (P = 0.097).

CONCLUSIONS

Buccally impacted maxillary canines are associated with an increased prevalence of root separation in the adjacent maxillary first premolars. This is likely because that buccally impacted canines encroach on the space needed for root development of the first premolars.

Publisher's Note: Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA [Phys. Rev. Lett. 117, 025001 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.117.025001.

Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA

A record fuel hot-spot pressure P_{hs}=56±7  Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium-tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ∼60% of the value required for ignition [A. Bose et al., Phys. Rev. E 93, 011201(R) (2016)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure is approximately 40% lower. Three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.

Differentiating Hemangioblastomas from Brain Metastases Using Diffusion-Weighted Imaging and Dynamic Susceptibility Contrast-Enhanced Perfusion-Weighted MR Imaging

BACKGROUND AND PURPOSE

On DWI and DSC-PWI, hemangioblastomas and brain metastases may exhibit different signal intensities depending on their cellularity and angiogenesis. The purpose of this study was to evaluate whether a hemangioblastoma can be differentiated from a single brain metastasis with DWI and DSC-PWI.

MATERIALS AND METHODS

We retrospectively reviewed DWI, DSC-PWI, and conventional MR imaging of 21 patients with hemangioblastomas and 30 patients with a single brain metastasis. Variables of minimum ADC and relative ADC were acquired by DWI and the parameter of relative maximum CBV, by DSC-PWI. Minimum ADC, relative ADC, and relative maximum CBV values were compared between hemangioblastomas and brain metastases by using the nonparametric Mann-Whitney test. The sensitivity, specificity, positive and negative predictive values, accuracy, and the area under the receiver operating characteristic curve were determined.

RESULTS

Both the minimum ADC values and relative ADC ratios were significantly higher in hemangioblastomas compared with brain metastases (P < .001 for both minimum ADC values and relative ADC ratios). The same was true for the relative maximum CBV ratio (P < .002). The threshold value of ≥6.59 for relative maximum CBV provided sensitivity, specificity, and accuracy of 95.24%, 53.33%, and 70.59%, respectively, for differentiating hemangioblastomas from brain metastases. Compared with relative maximum CBV, relative ADC had high sensitivity (95.24%), specificity (96.67%), and accuracy (96.08%) using the threshold value of ≥1.54. The optimal threshold value for minimum ADC was ≥1.1 × 10^-3 mm²/s.

CONCLUSIONS

DWI and DSC-PWI are helpful in the characterization and differentiation of hemangioblastomas from brain metastases. DWI appears to be the most efficient MR imaging technique for providing a distinct differentiation of the 2 tumor types.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Long-Range Plasmon-Assisted Energy Transfer between Fluorescent Emitters

We demonstrate plasmon-assisted energy transfer between fluorophores located at distances up to 7  μm on the top of a thin silver film. Thanks to the strong confinement and large propagation length of surface plasmon polaritons, the range of the energy transfer is almost 2 orders of magnitude larger than the values reported in the literature so far. The parameters driving the energy transfer range are thoroughly characterized and are in very good agreement with theoretically expected values.

IL-17A and IL-17F polymorphisms and gastric cancer risk: a meta-analysis

We conducted a meta-analysis of eligible studies to estimate the association between gastric cancer risk and rs2275913G>A IL-17A and rs763780T>C IL-17F polymorphisms. We searched the relevant studies in both Chinese and English through PubMed, the Web of Science, the Cochrane Library, and EMBASE up to January 1, 2014, including 3939 cases and 5407 controls. Seven eligible case-control studies were selected, including seven studies on rs2275913G>A IL-17A and four studies on rs763780T>C IL-17F. The rs2275913 AG [odds ratio (OR) = 1.50, 95% confidence interval (95%CI) = 1.04-2.15] and GG (OR = 1.40, 95%CI = 1.00-1.96) genotypes were significantly associated with increased risk of gastric cancer compared with the AA genotype. The rs763780 TC (OR = 1.47, 95%CI = 1.32-1.64) and TT (OR = 1.49, 95%CI = 1.11-1.99) gen-otypes can influence gastric cancer risk. Subgroup analysis showed that rs2275913 GG (OR = 1.35, 95%CI = 1.05-1.73) and rs763780 TC (OR= 1.44, 95%CI = 1.20-1.75) genotypes were not significantly associated with increased risk of gastric cancer in Japanese populations. Our meta-analysis is the first to indicate that the rs2275913G>A and rs763780T>C polymor-phisms are risk factors for gastric cancer development.