87 research outputs found
A broader role for AmyR in Aspergillus niger: regulation of the utilisation of d-glucose or d-galactose containing oligo- and polysaccharides
AmyR is commonly considered a regulator of starch degradation whose activity is induced by the presence of maltose, the disaccharide building block of starch. In this study, we demonstrate that the role of AmyR extends beyond starch degradation. Enzyme activity assays, genes expression analysis and growth profiling on d-glucose- and d-galactose-containing oligo- and polysaccharides showed that AmyR regulates the expression of some of the Aspergillus niger genes encoding α- and β-glucosidases, α- and β- galactosidases, as well as genes encoding α-amlyases and glucoamylases. In addition, we provide evidence that d-glucose or a metabolic product thereof may be the inducer of the AmyR system in A. niger and not maltose, as is commonly assumed
Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV
We present limits on anomalous WWZ and WW-gamma couplings from a search for
WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p
-> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron
Collider during the 1992-1995 run. The data sample corresponds to an integrated
luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling
parameters, the 95% CL limits on the CP-conserving couplings are
-0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a
form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also
presented.Comment: 11 pages, 2 figures, 2 table
Search For Heavy Pointlike Dirac Monopoles
We have searched for central production of a pair of photons with high
transverse energies in collisions at TeV using of data collected with the D\O detector at the Fermilab Tevatron in
1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could
rescatter pairs of nearly real photons into this final state via a box diagram.
We observe no excess of events above background, and set lower 95% C.L. limits
of on the mass of a spin 0, 1/2, or 1 Dirac
monopole.Comment: 12 pages, 4 figure
The Dijet Mass Spectrum and a Search for Quark Compositeness in bar{p}p Collisions at sqrt{s} = 1.8 TeV
Using the DZero detector at the 1.8 TeV pbarp Fermilab Tevatron collider, we
have measured the inclusive dijet mass spectrum in the central pseudorapidity
region |eta_jet| < 1.0 for dijet masses greater than 200 Gev/c^2. We have also
measured the ratio of spectra sigma(|eta_jet| < 0.5)/sigma(0.5 < |eta_jet| <
1.0). The order alpha_s^3 QCD predictions are in good agreement with the data
and we rule out models of quark compositeness with a contact interaction scale
< 2.4 TeV at the 95% confidence level.Comment: 11 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
Search for High Mass Photon Pairs in p-pbar --> gamma-gamma-jet-jet Events at sqrt(s)=1.8 TeV
A search has been carried out for events in the channel p-barp --> gamma
gamma jet jet. Such a signature can characterize the production of a
non-standard Higgs boson together with a W or Z boson. We refer to this
non-standard Higgs, having standard model couplings to vector bosons but no
coupling to fermions, as a "bosonic Higgs." With the requirement of two high
transverse energy photons and two jets, the diphoton mass (m(gamma gamma))
distribution is consistent with expected background. A 90(95)% C.L. upper limit
on the cross section as a function of mass is calculated, ranging from
0.60(0.80) pb for m(gamma gamma) = 65 GeV/c^2 to 0.26(0.34) pb for m(gamma
gamma) = 150 GeV/c^2, corresponding to a 95% C.L. lower limit on the mass of a
bosonic Higgs of 78.5 GeV/c^2.Comment: 9 pages, 3 figures. Replacement has new H->gamma gamma branching
ratios and corresponding new mass limit
Zgamma Production in pbarp Collisions at sqrt(s)=1.8 TeV and Limits on Anomalous ZZgamma and Zgammagamma Couplings
We present a study of Z +gamma + X production in p-bar p collisions at
sqrt{S}=1.8 TeV from 97 (87) pb^{-1} of data collected in the eegamma
(mumugamma) decay channel with the D0 detector at Fermilab. The event yield and
kinematic characteristics are consistent with the Standard Model predictions.
We obtain limits on anomalous ZZgamma and Zgammagamma couplings for form factor
scales Lambda = 500 GeV and Lambda = 750 GeV. Combining this analysis with our
previous results yields 95% CL limits |h{Z}_{30}| < 0.36, |h{Z}_{40}| < 0.05,
|h{gamma}_{30}| < 0.37, and |h{gamma}_{40}| < 0.05 for a form factor scale
Lambda=750 GeV.Comment: 17 Pages including 2 Figures. Submitted to PR
A Measurement of the W Boson Mass
We report a measurement of the W boson mass based on an integrated luminosity
of 82 pb from \ppbar collisions at TeV recorded in
1994--1995 by the \Dzero detector at the Fermilab Tevatron. We identify W
bosons by their decays to and extract the mass by fitting the transverse
mass spectrum from 28,323 W boson candidates. A sample of 3,563 dielectron
events, mostly due to Z to ee decays, constrains models of W boson production
and the detector. We measure \mw=80.44\pm0.10(stat)\pm0.07(syst)~GeV. By
combining this measurement with our result from the 1992--1993 data set, we
obtain \mw=80.43\pm0.11 GeV.Comment: 11 pages, 5 figure
Probing Hard Color-Singlet Exchange in ppbar Collisions at root-s=630 GeV and 1800 GeV
We present results on dijet production via hard color-singlet exchange in
proton-antiproton collisions at root-s = 630 GeV and 1800 GeV using the DZero
detector. The fraction of dijet events produced via color-singlet exchange is
measured as a function of jet transverse energy, separation in pseudorapidity
between the two highest transverse energy jets, and proton-antiproton
center-of-mass energy. The results are consistent with a color-singlet fraction
that increases with an increasing fraction of quark-initiated processes and
inconsistent with two-gluon models for the hard color-singlet.Comment: 16 pages, 6 figure
131I-metaiodobenzylguanidine (131I-MIBG) therapy for residual neuroblastoma: a mono-institutional experience with 43 patients
Incomplete response to therapy may compromise the outcome of children with advanced neuroblastoma. In an attempt to improve tumour response we incorporated 131I-metaiodobenzylguanidine (131I-MIBG) in the treatment regimens of selected stage 3 and stage 4 patients. Between 1986 and 1997, 43 neuroblastoma patients older than 1 year at diagnosis, 13 with stage 3 (group A) and 30 with stage 4 disease (group B) who had completed the first-line protocol without achieving complete response entered in this study. 131I-MIBG dose/course ranged from 2.5 to 5.5 Gbq (median, 3.7). The number of courses ranged from 1 to 5 (median 3) depending on the tumour response and toxicity. The most common acute side-effect was thrombocytopenia. Later side-effects included severe interstitial pneumonia in one patient, acute myeloid leukaemia in two, reduced thyroid reserve in 21. Complete response was documented in one stage 4 patient, partial response in 12 (two stage 3, 10 stage 4), mixed or no response in 25 (ten stage 3, 15 stage 4) and disease progression in five (one stage 3, four stage 4) Twenty-four patients (12/13 stage 3, 12/30 stage 4) are alive at 22–153 months (median, 59) from diagnosis. 131I-MIBG therapy may increase the cure rate of stage 3 and improve the response of stage 4 neuroblastoma patients with residual disease after first-line therapy. A larger number of patients should be treated to confirm these results but logistic problems hamper prospective and coordinated studies. Long-term toxicity can be severe. © 1999 Cancer Research Campaig
A novel formulation technology for baculoviruses protects biopesticide from degradation by ultraviolet radiation
Biopesticides are biological pest control agents that are viewed as safer alternatives to the synthetic chemicals that dominate the global insecticide market. A major constraint on the wider adoption of biopesticides is their susceptibility to the ultraviolet (UV: 290–400 nm) radiation in sunlight, which limits their persistence and efficacy. Here, we describe a novel formulation technology for biopesticides in which the active ingredient (baculovirus) is micro-encapsulated in an ENTOSTAT wax combined with a UV absorbant (titanium dioxide, TiO2). Importantly, this capsule protects the sensitive viral DNA from degrading in sunlight, but dissolves in the alkaline insect gut to release the virus, which then infects and kills the pest. We show, using simulated sunlight, in both laboratory bioassays and trials on cabbage and tomato plants, that this can extend the efficacy of the biopesticide well beyond the few hours of existing virus formulations, potentially increasing the spray interval and/or reducing the need for high application rates. The new formulation has a shelf-life at 30 °C of at least 6 months, which is comparable to standard commercial biopesticides and has no phytotoxic effect on the host plants. Taken together, these findings suggest that the new formulation technology could reduce the costs and increase the efficacy of baculovirus biopesticides, with the potential to make them commercially competitive alternatives to synthetic chemicals
- …