First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment.

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9 GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36 GeV/c^{2}, rejecting cross sections above 9.2×10^{-48} cm at the 90% confidence level.

Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data.

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5 GeV/c^{2} using 1.4×10^{4} kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure.

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41} cm^{2} (σ_{p}=5×10^{-40} cm^{2}) at 35 GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

First Searches for Axions and Axionlike Particles with the LUX Experiment.

The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118 kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12 eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6 eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16 keV/c^{2}. These are the most stringent constraints to date for these interactions.

Results from a Search for Dark Matter in the Complete LUX Exposure.

We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4} kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46} cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46} cm^{2} at 50 GeV c^{-2}.

Improved Limits on Scattering of Weakly Interacting Massive Particles from Reanalysis of 2013 LUX Data.

We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4×10^{4} kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium ß source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 GeV c^{-2}, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33 GeV c^{-2} WIMP mass.

Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment.

We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4×10^{4} kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=9.4×10^{-41} cm^{2} (σ_{p}=2.9×10^{-39} cm^{2}) at 33 GeV/c^{2}. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Limits on spin-dependent WIMP-nucleon cross sections from 225 live days of XENON100 data.

We present new experimental constraints on the elastic, spin-dependent WIMP-nucleon cross section using recent data from the XENON100 experiment, operated in the Laboratori Nazionali del Gran Sasso in Italy. An analysis of 224.6 live days×34 kg of exposure acquired during 2011 and 2012 revealed no excess signal due to axial-vector WIMP interactions with 129Xe and 131Xe nuclei. This leads to the most stringent upper limits on WIMP-neutron cross sections for WIMP masses above 6 GeV/c², with a minimum cross section of 3.5×10(-40) cm² at a WIMP mass of 45 GeV/c², at 90% confidence level.

Dark matter results from 225 live days of XENON100 data.

We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso for 13 months during 2011 and 2012. XENON100 features an ultralow electromagnetic background of (5.3 ± 0.6) × 10(-3) events/(keV(ee) × kg × day) in the energy region of interest. A blind analysis of 224.6 live days × 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the predefined nuclear recoil energy range of 6.6-30.5 keV(nr) are consistent with the background expectation of (1.0 ± 0.2) events. A profile likelihood analysis using a 6.6-43.3 keV(nr) energy range sets the most stringent limit on the spin-independent elastic weakly interacting massive particle-nucleon scattering cross section for weakly interacting massive particle masses above 8 GeV/c(2), with a minimum of 2 × 10(-45) cm(2) at 55 GeV/c(2) and 90% confidence level.

Myocardial tissue Doppler assessment of diastolic function in the growth-restricted fetus.

OBJECTIVES: Myocardial tissue Doppler (MTD) is a technique for the measurement of myocardial velocities in systole and diastole. This study evaluates the use of MTD in the assessment of cardiac diastolic function in fetuses with intrauterine growth restriction (IUGR) with placental insufficiency and in appropriate-for-gestational age (AGA) fetuses with hypertensive mothers. METHODS: This study included 14 IUGR fetuses with placental insufficiency (Group 1), 13 AGA fetuses with hypertensive mothers (Group 2), and 29 AGA fetuses with healthy mothers (Group 3). Patients with other diseases were excluded. All fetuses had a gestational age of at least 25 weeks. MTD assessment was performed with the sample volume placed at the basal segment of the left ventricular side wall (LV), the interventricular septum (IVS) and the right ventricular free wall (RV). E'/A' ratios were calculated for each location. Mitral and tricuspid flows were assessed by conventional spectral pulsed Doppler. RESULTS: Significant differences were found between groups for E'/A' at the IVS (P < 0.001) and LV (P = 0.009), with a higher mean (+/- SD) value in Group 1 (IVS: 0.92 +/- 0.28; LV: 0.85 +/- 0.19) than in Groups 2 (IVS: 0.62 +/- 0.09; LV: 0.68 +/- 0.14) and 3 (IVS: 0.71 +/- 0.14; LV: 0.69 +/- 0.15). In the RV, there was no statistically significant difference in the E'/A' ratio (P = 0.2). No differences were observed for mitral and tricuspid flow velocities and ratios. CONCLUSIONS: Using MTD, the ratios between early and late diastolic myocardial velocities are higher in IUGR fetuses than in AGA fetuses at the IVS and the LV, regardless of the presence of maternal hypertension. MTD may be more sensitive than atrioventricular spectral Doppler for the detection of ventricular diastolic dysfunction in IUGR fetuses.

Energetic study of the disordered solvent in the crystal structure of an isoxazole derivative. Erratum.

An error in printing is reported. In the paper by Pani et al. [Acta Cryst. (1998), B54, 872-876] the value of Deltarho(max) is given incorrectly in the last sentence on page 874. The sentence should read 'In the last difference Fourier map, the highest Deltarho values were found near the Cl atoms (Deltarho(max) +0.32 e Å(-3)); the final reliability indexes were R(1) = 0.072 over 1762 F(o) > 4sigma(F(o)) and wR(2) = 0.228 on 4029 F(o)(2) for 245 refined parameters, with a goodness-of-fit of 0.96.'

Randomised trial of nadolol alone or with isosorbide mononitrate for primary prophylaxis of variceal bleeding in cirrhosis. Gruppo-Triveneto per L'ipertensione portale (GTIP)

BACKGROUND: The risk of having a first cirrhosis-associated variceal bleed is lowered by about 50% by beta-blockers. Use of beta-blockers is currently recommended for patients with cirrhosis and oesophageal varices that are at risk of bleeding. We aimed to test the effectiveness of isosorbide mononitrate as an adjunct to the beta-blocker nadolol in the prophylaxis of first variceal bleeding in these patients. METHODS: We did a randomised multicentre study to compare the non-selective beta-blocker, nadolol, with nadolol plus isosorbide mononitrate in 146 relatively well (Child-Pugh score < or = 11) patients who had oesophageal varices at risk of bleeding. Patients on nadolol alone received a single oral 40 mg daily dose. Every second day the dose was titrated to achieve 20-25% decrease in resting heart rate (maximum dose 160 mg daily). Patients receiving both drugs received nadolol as above then isosorbide mononitrate was added starting with 10 mg orally twice daily, which was increased to 20 mg unless hypotension or severe headache occurred. The main endpoint was the occurrence of variceal bleeding of any severity. Patients were followed up for up to 40 months. FINDINGS: During the study period 11 of 74 patients from the nadolol alone group and four of 72 from the nadolol plus isosorbide mononitrate group had variceal bleeding (log-rank test p = 0.03). Cumulative risk of variceal bleeding was 18% in the nadolol group and 7.5% in the combined treatment group (95% CI for difference 1-25%). Two patients in each group had a non-variceal bleed related to portal hypertension. 14 patients from the nadolol only group and eight from the combined treatment group died during the study period (log-rank test p = 0.09). Four and eight patients, respectively, had to discontinue one of the drugs because of side-effects. INTERPRETATION: Nadolol plus isosorbide mononitrate is significantly more effective than nadolol alone in the primary prophylaxis of variceal bleeding in relatively well patients with cirrhosis, and has few side-effects.

Hydrolysis of inulin: a kinetic study of the reaction catalyzed by an inulinase from Aspergillus ficuum.

A kinetic study of the hydrolysis of inulin was performed by using as catalyst a commercial inulinase from Aspergillus ficuum. The reaction was studied carrying out initial rate as well as time course measurements. Both inulinase and invertase activities of the enzyme were taken into account, and the corresponding kinetic parameters were determined in the temperature range 30-50 degrees C. The activation energies of the turnover constant for inulinase and invertase activities were found to be similar (56-57 kJ x mol(-1)). The ratio S/I of invertase to inulinase activity was 1.6 regardless of temperature. The thermal degradation of the enzyme was also investigated up to 70 degrees C, and an activation energy of 350-370 kJ x mol(-1) was evaluated.

Inhibiting action of chlorophenols on biodegradation of phenol and its correlation with structural properties of inhibitors.

An activated sludge conditioned to a low concentration of phenol was used for the biodegradation of phenol in the presence of Chlorophenols, measuring the inhibiting action of all the latter compounds and expressing it as p/(50.) As a structural property to be correlated with the measured values, the lipophilicity (log P) of the Chlorophenols was reevaluated with a new apparatus. Values of p/(50)p are better correlated with the number of chloro substituents in the inhibitor, provided a specific effect of substituents ortho to the phenolic function is considered. New results are compared with previous measurements effected on a different activated sludge.

Enzymatic hydrolysis of cellulosic materials: A kinetic study.

A kinetic study of the enzymatic hydrolysis of two celluloses with different structural features was performed at various temperatures (26-50 degrees C). The enzymatic system consisted of three types of enzymes: E(1)-beta-1,4-glucan glucanohydrolase; E(2)-beta-1,4-glucan cellobiohydrolase; and E(3)-beta-glucosidase. A mathematical model for the mechanism of the hydrolysis of cellulosic materials catalyzed by a multienzymatic system was checked and a good rationalization of the experimental results was achieved. Uncompetitive and competitive glucose inhibition on E(1) and E(2), respectively, appeared to occur for both substrates. Inhibition by cellobiose was checked at 34 degrees C on one substrate. The V(max), K(m), and glucose inhibition constants were optimized and their dependence on temperature determined.