1,024 research outputs found
Substrate induction and glucose repression of maltose utilization by Streptomyces coelicolor A3(2) is controlled by malR, a member of the lacI-galR family of regulatory genes
malR of Strepomyces coelicolor A3(2) encodes a homologue of the Lacl/Galr family of repressor proteins, and is divergently transcribed from the malEFG gene cluster, which encodes components of an ATP-dependent transport system that is required for maltose utilization. Transcription of malE was induced by maltose and repressed by glucose. Disruption or deletion of malR resulted in constitutive, glucose-insensitive malE transcription at a level markedly above that observed in the parental malR+ strain, and overproduction of MalR prevented growth on maltose as carbon source. Consequently, MalR plays a crucial role in both substrate induction and glucose repression of maltose utilization. MalR is expressed from a single promoter with transcription initiating at the first G of the predicted GTG translataion start codon
Chiral Extrapolation of Lattice Data for Heavy Baryons
The masses of heavy baryons containing a b quark have been calculated
numerically in lattice QCD with pion masses which are much larger than its
physical value. In the present work we extrapolate these lattice data to the
physical mass of the pion by applying the effective chiral Lagrangian for heavy
baryons, which is invariant under chiral symmetry when the light quark masses
go to zero and heavy quark symmetry when the heavy quark masses go to infinity.
A phenomenological functional form with three parameters, which has the correct
behavior in the chiral limit and appropriate behavior when the pion mass is
large, is proposed to extrapolate the lattice data. It is found that the
extrapolation deviates noticably from the naive linear extrapolation when the
pion mass is smaller than about 500MeV. The mass differences between Sigma_b
and Sigma_b^* and between Sigma_b^{(*)} and Lambda_b are also presented.
Uncertainties arising from both lattice data and our model parameters are
discussed in detail. We also give a comparision of the results in our model
with those obtained in the naive linear extrapolations.Comment: 29 pages, 9 figure
Health utility assessments in individuals undergoing diagnostic and surveillance colonoscopy: improved discrimination with a cancer-specific scale
Purpose
To compare the sensitivity and discriminant validity of generic and cancer-specific measures for assessing health-related quality of life (HRQoL) for individuals undergoing diagnostic or surveillance colonoscopy for colorectal cancer.
Methods
HRQoL was assessed using EQ-5D-5L (generic), and EORTC QLQ-C30 (cancer-specific) scales, 14 days after (baseline) and one-year following colonoscopy (follow-up). Utility scores were calculated by mapping EORTC-QLQ-C30 onto QLU-C10D. Differences between participants with different indications for colonoscopy (positive faecal occult blood test (FOBT), surveillance, or symptoms) and colonoscopy findings (no polyps, polyps, or cancer) were tested using Wilcoxon-Mann–Whitney and Kruskal–Wallis H tests. Sensitivity was assessed by calculating the ceiling effects (proportion reporting the best possible level).
Results
246 adults completed the survey, including those undergoing colonoscopy for symptoms (n = 87), positive FOBT (n = 92) or surveillance (n = 67). Those with symptoms had the lowest HRQoL at both baseline and follow-up, with differences observed within the HRQoL domains/areas of role function, appetite loss and bowel function on the QLU-C10D. No differences were found in HRQoL when stratified by findings at colonoscopy with both measures or when comparing baseline and follow-up responses. Participants reporting full health with EQ-5D-5L (21% at baseline and 16% at follow-up) still had problems on the QLU-C10D, with fatigue and sleep at baseline and with role function and fatigue at follow-up.
Conclusion
Patients undergoing colonoscopy for symptoms had lower HRQoL compared to surveillance or positive FOBT. The cancer-specific QLU-C10D was more sensitive and had greater discriminant ability between patients undergoing colonoscopy for different indications
The Effects of Atmospheric Dispersion on High-Resolution Solar Spectroscopy
We investigate the effects of atmospheric dispersion on observations of the
Sun at the ever-higher spatial resolutions afforded by increased apertures and
improved techniques. The problems induced by atmospheric refraction are
particularly significant for solar physics because the Sun is often best
observed at low elevations, and the effect of the image displacement is not
merely a loss of efficiency, but the mixing of information originating from
different points on the solar surface. We calculate the magnitude of the
atmospheric dispersion for the Sun during the year and examine the problems
produced by this dispersion in both spectrographic and filter observations. We
describe an observing technique for scanning spectrograph observations that
minimizes the effects of the atmospheric dispersion while maintaining a regular
scanning geometry. Such an approach could be useful for the new class of
high-resolution solar spectrographs, such as SPINOR, POLIS, TRIPPEL, and ViSP
Masses of ground and excited-state hadrons
We present the first Dyson-Schwinger equation calculation of the light hadron
spectrum that simultaneously correlates the masses of meson and baryon ground-
and excited-states within a single framework. At the core of our analysis is a
symmetry-preserving treatment of a vector-vector contact interaction. In
comparison with relevant quantities the
root-mean-square-relative-error/degree-of freedom is 13%. Notable amongst our
results is agreement between the computed baryon masses and the bare masses
employed in modern dynamical coupled-channels models of pion-nucleon reactions.
Our analysis provides insight into numerous aspects of baryon structure; e.g.,
relationships between the nucleon and Delta masses and those of the
dressed-quark and diquark correlations they contain.Comment: 25 pages, 7 figures, 4 table
FIT for purpose: study protocol for a randomized controlled trial to personalize surveillance colonoscopy for individuals at elevated risk of colorectal cancer
PURPOSE: There is increasing demand for colorectal cancer (CRC) surveillance, but healthcare capacity is limited. The burden on colonoscopy resources could be reduced by personalizing surveillance frequency using the fecal immunochemical test (FIT). This study will determine the safety, cost-effectiveness, and patient acceptance of using FIT to extend surveillance colonoscopy intervals for individuals at elevated risk of CRC. METHODS: This multicenter, prospective, randomized controlled trial will invite participants who are scheduled for surveillance colonoscopy (due to a personal history of adenomas or a family history of CRC) and who have returned a low fecal hemoglobin (< 2 μg Hb/g feces; F-Hb) using a two-sample FIT (OC Sensor, Eiken Chemical Company) in the prior 3 years. A total of 1344 individuals will be randomized to either surveillance colonoscopy as scheduled or delayed by 1 or 2 years for individuals originally recommended a 3- or 5-year surveillance interval, respectively. The primary endpoint is incidence of advanced neoplasia (advanced adenoma and/or CRC). Secondary endpoints include cost-effectiveness and consumer acceptability of extending surveillance intervals, determined using surveys and discrete choice experiments. CONCLUSION: This study will establish the safety, cost-effectiveness, and acceptability of utilizing a low FIT Hb result to extend colonoscopy surveillance intervals in a cohort at elevated risk for CRC. This personalized approach to CRC surveillance will lead to a reduction in unnecessary colonoscopies, increases in healthcare savings, and a better patient experience. TRIAL REGISTRATION: Registration was approved on December 9, 2019 with the Australian New Zealand Clinical Trials Registry ANZCTR 12619001743156.Jean M. Winter, Kathryn J. Cornthwaite, Graeme P. Young, Carlene Wilson, Gang Chen, Richard Woodman, Michelle Coats, Robert Fraser, Charles Cock, Peter Bampton, Erin L. Symond
Physics Opportunities with the 12 GeV Upgrade at Jefferson Lab
This white paper summarizes the scientific opportunities for utilization of
the upgraded 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF) and
associated experimental equipment at Jefferson Lab. It is based on the 52
proposals recommended for approval by the Jefferson Lab Program Advisory
Committee.The upgraded facility will enable a new experimental program with
substantial discovery potential to address important topics in nuclear,
hadronic, and electroweak physics.Comment: 64 page
Natural product proteomining, a quantitative proteomics platform, allows rapid discovery of biosynthetic gene clusters for different classes of natural products
Microbial Biotechnolog
Corrigendum to “Carbonate delta drift: A new sediment drift type” [Mar. Geol. 401 (2018) 98–111]
The authors regret the mistake in the drawing of the delta drift architecture in figure 11. The authors would like to apologise for any inconvenience caused. [Figure presented
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
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