292 research outputs found
Cold endoscopic mucosal resection of large sessile serrated polyps at colonoscopy (with video)
The optimal technique for the resection of sessile serrated polyps (SSPs) is unknown, with established limitations and risks with conventional polypectomy. Although cold snare polypectomy is safe, the efficacy of piecemeal resection for large lesions is untested. In this study, we evaluate the safety and efficacy of cold endoscopic mucosal resection (EMR) for large SSPs.Patients presenting for elective colonoscopy at an academic endoscopy center with 1 or more SSPs ≥10mm in size were enrolled, excluding those on anticoagulants or antiplatelets other than aspirin. Lesions were resected with a cold EMR technique comprising submucosal injection of succinylated gelatin and dilute methylene blue before piecemeal cold snare resection of all visible polyp with a margin of normal tissue. Outcomes were the presence of residual serrated neoplasia in biopsies from the defect margin, and findings on surveillance colonoscopy.Cold EMR was performed on 163 SSPs during 105 procedures in 99 patients (97% female; median age 57 years). The mean size was 17.5 mm: 61 SSPs were ≥20 mm, 13 SSPs ≥30 mm, and 97.5% were in the proximal colon. Cytological dysplasia was present in 2 (1.2%). Margin biopsies were positive in 2 (1.2%) lesions. Surveillance colonoscopy for 82% of lesions (median 5 months) showed residual serrated tissue in 1, treated with cold snare, but no evidence of recurrence in the remainder. Minor adverse events were seen in 3 patients; no delayed bleeding was observed.Cold EMR is a safe and effective method for the removal of large SSPs
N-Terminal sequence of creatine kinase from skeletal muscle of rabbit and rhesus monkey
1. 1. The first 20 amino acids from the N-terminus of skeletal muscle (MM) creatine kinase from both rabbit and rhesus monkey have been identified and these sequences show considerable homology.2. 2. Contrary to an earlier report, the N-terminus was not found to be blocked.3. 3. Both of these sequences show much less homology with the N-terminal sequence of heart muscle (MM) creatine kinase and no homology with that of the heart muscle mitochondrial (MiMi) isozyme.4. 4. No homology was found between the N-terminal sequence of the mitochondrial isozyme and the URF (unidentified reading frame) proteins of the human mitochondrial genome, indicating that the mitochondrial enzyme is encoded by nuclear genes. This suggests the possibility that an N-terminal peptide may be cleaved from the mitochondrial isozyme on its translocation across the mitochondrial membrane.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25924/1/0000487.pd
What Precision Electroweak Physics Says About the SU(6)/Sp(6) Little Higgs
We study precision electroweak constraints on the close cousin of the
Littlest Higgs, the SU(6)/Sp(6) model. We identify a near-oblique limit in
which the heavy W' and B' decouple from the light fermions, and then calculate
oblique corrections, including one-loop contributions from the extended top
sector and the two Higgs doublets. We find regions of parameter space that give
acceptably small precision electroweak corrections and only mild fine tuning in
the Higgs potential, and also find that the mass of the lightest Higgs boson is
relatively unconstrained by precision electroweak data. The fermions from the
extended top sector can be as light as 1 TeV, and the W' can be as light as 1.8
TeV. We include an independent breaking scale for the B', which can still have
a mass as low as a few hundred GeV.Comment: 52 pages, 16 figure
The Diboson Excess: Experimental Situation and Classification of Explanations; A Les Houches Pre-Proceeding
We examine the `diboson' excess at TeV seen by the LHC experiments
in various channels. We provide a comparison of the excess significances as a
function of the mass of the tentative resonance and give the signal cross
sections needed to explain the excesses. We also present a survey of available
theoretical explanations of the resonance, classified in three main approaches.
Beyond that, we discuss methods to verify the anomaly, determining the major
properties of the various surpluses and exploring how different models can be
discriminated. Finally, we give a tabular summary of the numerous explanations,
presenting their main phenomenological features.Comment: 37 pages, 9 Figures, 1 Tabl
A Survey of Computational Tools in Solar Physics
The SunPy Project developed a 13-question survey to understand the software
and hardware usage of the solar physics community. 364 members of the solar
physics community, across 35 countries, responded to our survey. We found that
990.5% of respondents use software in their research and 66% use the
Python scientific software stack. Students are twice as likely as faculty,
staff scientists, and researchers to use Python rather than Interactive Data
Language (IDL). In this respect, the astrophysics and solar physics communities
differ widely: 78% of solar physics faculty, staff scientists, and researchers
in our sample uses IDL, compared with 44% of astrophysics faculty and
scientists sampled by Momcheva and Tollerud (2015). 634% of respondents
have not taken any computer-science courses at an undergraduate or graduate
level. We also found that most respondents utilize consumer hardware to run
software for solar-physics research. Although 82% of respondents work with data
from space-based or ground-based missions, some of which (e.g. the Solar
Dynamics Observatory and Daniel K. Inouye Solar Telescope) produce terabytes of
data a day, 14% use a regional or national cluster, 5% use a commercial cloud
provider, and 29% use exclusively a laptop or desktop. Finally, we found that
734% of respondents cite scientific software in their research, although
only 423% do so routinely
Graviton Production By Two Photon and Electron-Photon Processes In Kaluza-Klein Theories With Large Extra Dimensions
We consider the production of gravitons via two photon and electron-photon
fusion in Kaluza-Klein theories which allow TeV scale gravitational
interactions. We show that at electron-positron colliders, the processes l+l-
-> l+ l- graviton, with l=e, mu, can lead to a new signal of low energy gravity
of the form l+l- -> l+l- + missing energy which is well above the Standard
Model background. For example, with two extra dimensions at the Next Linear
Collider with a center of mass energy of 500 or 1000 GeV, hundreds to thousands
such l+ l- graviton events may be produced if the scale of the gravitational
interactions, M_D, is around a few TeV. At a gamma-electron collider, more
stringent bounds may be placed on M_D via the related reaction e^-\gamma -> e^-
graviton. For instance, if a 1TeV electron positron collider is converted to an
electron-photon collider, a bound of ~10TeV may be placed on the scale M_D if
the number of extra dimensions delta=2 while a bound of ~4TeV may be placed if
delta=4.Comment: 25 pages 6 figures, minor changes made in the text and changes in
reference
The Little Higgs from a Simple Group
We present a model of electroweak symmetry breaking in which the Higgs boson
is a pseudo-Nambu-Goldstone boson. By embedding the standard model SU(2) x U(1)
into an SU(4) x U(1) gauge group, one-loop quadratic divergences to the Higgs
mass from gauge and top loops are canceled automatically with the minimal
particle content. The potential contains a Higgs quartic coupling which does
not introduce one-loop quadratic divergences. Our theory is weakly coupled at
the electroweak scale, it has new weakly coupled particles at the TeV scale and
a cutoff above 10 TeV, all without fine tuning. We discuss the spectrum of the
model and estimate the constraints from electroweak precision measurements.Comment: 29 pages, referencing error corrected after death threats, dude
remove
Gauge Boson - Gauge Boson Scattering in Theories with Large Extra Dimensions
We consider the scattering amplitudes of the form V_1 V_2 -> V_3 V_4, where
V_i=\gamma, Z, W or g(=gluon) are the Standard Model gauge bosons, due to
graviton exchange in Kaluza-Klein theories with large extra dimensions. This
leads to a number of experimentally viable signatures at high energy leptonic
and hadronic colliders. We discuss the observability or future limits on the
scale of the gravitational interactions (m_D), that may be obtained at an e+e-
Next Linear Collider (NLC) and at the LHC, by studying some of these type of
gauge boson scattering processes. We find that the attainable limits through
these type of processes are: m_D > 3 TeV at the NLC and m_D > 6 TeV at the LHC.Comment: 27 pages, plain latex, 7 figures embadded in the text using epsfi
Dijet Production at Hadron Colliders in Theories with Large Extra Dimensions
We consider the production of high invariant mass jet pairs at hadron
colliders as a test for TeV scale gravitational effects. We find that this
signal can probe effective Planck masses of about 10 TeV at the LHC with center
of mass energy of 14 TeV and 1.5 TeV at the Tevatron with center of mass energy
of 2 TeV. These results are compared to analogous scattering processes at
leptonic colliders.Comment: 15 pages with 3 figure
The Discovery Potential of a Super B Factory
The Proceedings of the 2003 SLAC Workshops on flavor physics with a high
luminosity asymmetric e+e- collider. The sensitivity of flavor physics to
physics beyond the Standard Model is addressed in detail, in the context of the
improvement of experimental measurements and theoretical calculations.Comment: 476 pages. Printed copies may be obtained by request to
[email protected] . arXiv admin note: v2 appears to be identical to v
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