Search for muon-neutrino to electron-neutrino transitions in MINOS.

This Letter reports on a search for nu(mu) --> nu(e) transitions by the MINOS experiment based on a 3.14x10(20) protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 27+/-5(stat)+/-2(syst) events predicted by the measurements in the Near Detector. If interpreted in terms of nu(mu) --> nu(e) oscillations, this 1.5sigma excess of events is consistent with sin2(2theta(13)) comparable to the CHOOZ limit when |Delta m2|=2.43x10(-3) eV2 and sin2(2theta(23))=1.0 are assumed.

Search for active neutrino disappearance using neutral-current interactions in the MINOS long-baseline experiment.

We report the first detailed comparisons of the rates and spectra of neutral-current neutrino interactions at two widely separated locations. A depletion in the rate at the far site would indicate mixing between nu(mu) and a sterile particle. No anomalous depletion in the reconstructed energy spectrum is observed. Assuming oscillations occur at a single mass-squared splitting, a fit to the neutral- and charged-current energy spectra limits the fraction of nu(mu) oscillating to a sterile neutrino to be below 0.68 at 90% confidence level. A less stringent limit due to a possible contribution to the measured neutral-current event rate at the far site from nu(e) appearance at the current experimental limit is also presented.

Testing Lorentz invariance and CPT conservation with NuMI neutrinos in the MINOS near detector.

A search for a sidereal modulation in the MINOS near detector neutrino data was performed. If present, this signature could be a consequence of Lorentz and CPT violation as predicted by the effective field theory called the standard-model extension. No evidence for a sidereal signal in the data set was found, implying that there is no significant change in neutrino propagation that depends on the direction of the neutrino beam in a sun-centered inertial frame. Upper limits on the magnitudes of the Lorentz and CPT violating terms in the standard-model extension lie between 10(-4) and 10(-2) of the maximum expected, assuming a suppression of these signatures by a factor of 10(-17).

Measurement of neutrino oscillations with the MINOS detectors in the NuMI beam.

This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |Deltam2| = (2.43+/-0.13) x 10(-3) eV2 (68% C.L.) and mixing angle sin2(2theta) > 0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively.

Reduction of 4-nitroquinoline 1-oxide to 4-hydroxyaminoquinoline 1-oxide in lysates of cytomegalovirus-infected cells.

The rates of virus inactivation by 4-nitroquinoline 1-oxide (NQO) and 4-hydroxyaminoquinoline 1-oxide (HAQO) were compared and samples of cytomegalovirus (CMV)-infected cell lysates to which NQO had been added were examined for the presence of HAQO. These experiments demonstrated that (i) CMV inactivation by HAQO was more rapid than with NQO, (ii) virus inactivation by either NQO or HAQO failed to demonstrate a photodynamic component, and (iii) NQO-treated stocks contained HAQO, indicating reduction of NQO to HAQO. The results support the concept that metabolism of NQO to HAQO enhances the genotoxic effect of NQO.

beta-Endorphin and its metabolites stimulate motility of the dog small intestine.

Previous studies have demonstrated that beta-endorphin and enkephalins are released into the systemic circulation by the pituitary and adrenal medulla, respectively. To determine whether the small intestine could be a target for circulating beta-endorphin, segments of small intestine were removed from anesthetized dogs and perfused with Krebs-bicarbonate buffer containing beta-endorphin (1 microgram/ml), while motility was recorded and venous effluent collected in 1-min fractions (23 ml). beta-Endorphin significantly (P less than .002) increased motility of intestinal segments. High-performance liquid chromatographic analysis of the venous effluent identified, among others, several alpha- and gamma-type endorphins. Several of the identified peptide fragments were then perfused through intestinal segments to determine their motility effects. alpha-Endorphin, gamma-endorphin, des-tyrosine-alpha-endorphin and des-tyrosine-gamma-endorphin, significantly increased motility at doses of 1 microgram/ml. These responses were characterized by an increase in phasic contractions of constant amplitude and frequency. To determine regional specificity and site of beta-endorphin metabolism during perfusion, we studied time course processing of beta-endorphin in mucosal and muscularis homogenates in vitro. The mucosa was much more enzymatically active than the muscularis and produced 3-fold more gamma-endorphin than alpha-endorphin, whereas the reverse was found in the muscularis. These studies demonstrate that the small intestine can metabolize beta-endorphin into a number of active fragments which increase motility and suggest a regional specificity of enzymatic processing of beta-endorphin in the dog intestine.