733 research outputs found
Maximizing the physics potential of B±âϱΌ+ÎŒâ decays
We present a method that maximizes the experimental sensitivity to new physics contributions in ±â±âą+âąâ decays. This method relies on performing an unbinned maximum likelihood fit to both the measured dimuon 2 distribution of ±â±âą+âąâ decays, and theory calculations at spacelike 2, where QCD predictions are most reliable. Using known properties of the decay amplitude we employ a dispersion relation to describe the nonlocal hadronic contributions across spacelike and time like 2 regions. The fit stability and the sensitivity to new physics couplings and new sources of âą-violation are studied for current and future data-taking scenarios, with the LHCb experiment as an example. The proposed method offers a precise and reliable way to search for new physics in these decays
c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis
Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1, are essential for the reduction of U(VI) and formation of extracelluar UO (2) nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC (metal reduction), previously implicated in Mn(IV) and Fe(III) reduction, directly transferred electrons to U(VI). Additionally, deletions of mtrC and/or omcA significantly affected the in vivo U(VI) reduction rate relative to wild-type MR-1. Similar to the wild-type, the mutants accumulated UO (2) nanoparticles extracellularly to high densities in association with an extracellular polymeric substance (EPS). In wild-type cells, this UO (2)-EPS matrix exhibited glycocalyx-like properties and contained multiple elements of the OM, polysaccharide, and heme-containing proteins. Using a novel combination of methods including synchrotron-based X-ray fluorescence microscopy and high-resolution immune-electron microscopy, we demonstrate a close association of the extracellular UO (2) nanoparticles with MtrC and OmcA (outer membrane cytochrome). This is the first study to our knowledge to directly localize the OM-associated cytochromes with EPS, which contains biogenic UO (2) nanoparticles. In the environment, such association of UO (2) nanoparticles with biopolymers may exert a strong influence on subsequent behavior including susceptibility to oxidation by O (2) or transport in soils and sediments
Epigenetic remodelling licences adult cholangiocytes for organoid formation and liver regeneration.
Following severe or chronic liver injury, adult ductal cells (cholangiocytes) contribute to regeneration by restoring both hepatocytes and cholangiocytes. We recently showed that ductal cells clonally expand as self-renewing liver organoids that retain their differentiation capacity into both hepatocytes and ductal cells. However, the molecular mechanisms by which adult ductal-committed cells acquire cellular plasticity, initiate organoids and regenerate the damaged tissue remain largely unknown. Here, we describe that ductal cells undergo a transient, genome-wide, remodelling of their transcriptome and epigenome during organoid initiation and in vivo following tissue damage. TET1-mediated hydroxymethylation licences differentiated ductal cells to initiate organoids and activate the regenerative programme through the transcriptional regulation of stem-cell genes and regenerative pathways including the YAP-Hippo signalling. Our results argue in favour of the remodelling of genomic methylome/hydroxymethylome landscapes as a general mechanism by which differentiated cells exit a committed state in response to tissue damage.RCUK
Cancer Research UK
ERC
H2020
Wellcome Trus
Testing innovative strategies to reduce the social gradient in the uptake of bowel cancer screening: a programme of four qualitatively enhanced randomised controlled trial
Background: Bowel cancer screening reduces cancer-specific mortality. There is a socioeconomic gradient in the uptake of the English NHS Bowel Cancer Screening Programme (BCSP), which may lead to inequalities in cancer outcomes. Objective: To reduce socioeconomic inequalities in uptake of the NHS BCSPâs guaiac faecal occult blood test (gFOBt) without compromising uptake in any socioeconomic group. Design: Workstream 1 explored psychosocial determinants of non-uptake of gFOBt in focus groups and interviews. Workstream 2 developed and tested four theoretically based interventions: (1) âgistâ information, (2) a ânarrativeâ leaflet, (3) âgeneral practice endorsementâ (GPE) and (4) an âenhanced reminderâ (ER). Workstream 3 comprised four national cluster randomised controlled trials (RCTs) of the cost-effectiveness of each intervention. Methods: Interventions were co-designed with user panels, user tested using interviews and focus groups, and piloted with postal questionnaires. RCTs compared âusual careâ (existing NHS BCSP invitations) with usual care plus each intervention. The four trials tested: (1) âgistâ leaflet (nâ=â163,525), (2) ânarrativeâ leaflet (nâ=â150,417), (3) GPE on the invitation letter (nâ=â265,434) and (4) ER (nâ=â168,480). Randomisation was based on day of mailing of the screening invitation. The Index of Multiple Deprivation (IMD) score associated with each individualâs home address was used as the marker of socioeconomic circumstances (SECs). Change in the socioeconomic gradient in uptake (interaction between treatment group and IMD quintile) was the primary outcome. Screening uptake was defined as the return of a gFOBt kit within 18 weeks of the invitation that led to a âdefinitiveâ test result of either ânormalâ (i.e. no further investigation required) or âabnormalâ (i.e. requiring referral for further testing). Difference in overall uptake was the secondary outcome. Results: The gist and narrative trials showed no effect on the SECs gradient or overall uptake (57.6% and 56.7%, respectively, compared with 57.3% and 58.5%, respectively, for usual care; all p-values >â0.05). GPE showed no effect on the gradient (pâ=â0.5) but increased overall uptake [58.2% vs. 57.5% in usual care, odds ratio (OR)â=â1.07, 95% confidence interval (CI) 1.04 to 1.10; pâ<â0.0001]. ER showed a significant interaction with SECs (pâ=â0.005), with a stronger effect in the most deprived IMD quintile (14.1% vs. 13.3% in usual care, ORâ=â1.11, 95% CI 1.04 to 1.20; pâ=â0.003) than the least deprived (34.7% vs. 34.9% in usual care ORâ=â1.00, 95% CI 0.94 to 1.06; pâ=â0.98), and higher overall uptake (25.8% vs. 25.1% in usual care, ORâ=â1.07, 95% CI 1.03 to 1.11; pâ=â0.001). All interventions were inexpensive to provide. Limitations: In line with NHS policy, the gist and narrative leaflets supplemented rather than replaced existing NHS BCSP information. This may have undermined their effect. Conclusions: Enhanced reminder reduced the gradient and modestly increased overall uptake, whereas GPE increased overall uptake but did not reduce the gradient. Therefore, given their effectiveness and very low cost, the findings suggest that implementation of both by the NHS BCSP would be beneficial. The gist and narrative results highlight the challenge of achieving equitable delivery of the screening offer when all communication is written; the format is universal and informed decision-making mandates extensive medical information. Future work: Socioculturally tailored research to promote communication about screening with family and friends should be developed and evaluated. Trial registration: Current Controlled Trials ISRCTN74121020. Funding: This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 5, No. 8. See the NIHR Journals Library website for further project information
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
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