1,597 research outputs found
Intravital FRAP imaging using an E-cadherin-GFP mouse reveals disease- and drug-dependent dynamic regulation of cell-cell junctions in live tissue
E-cadherin-mediated cell-cell junctions play a prominent role in maintaining the epithelial architecture. The disruption or deregulation of these adhesions in cancer can lead to the collapse of tumor epithelia that precedes invasion and subsequent metastasis. Here we generated an E-cadherin-GFP mouse that enables intravital photobleaching and
quantification of E-cadherin mobility in live tissue without affecting normal biology. We demonstrate the broad applications of this mouse by examining
E-cadherin regulation in multiple tissues, including mammary, brain, liver, and kidney tissue, while specifically monitoring E-cadherin mobility during
disease progression in the pancreas. We assess E-cadherin stability in native pancreatic tissue upon genetic manipulation involving Kras and p53
or in response to anti-invasive drug treatment and gain insights into the dynamic remodeling of E-cadherin during in situ cancer progression. FRAP in the E-cadherin-GFP mouse, therefore, promises to be a valuable tool to fundamentally expand our understanding of E-cadherin-mediated events in native microenvironments
First Observation of the Doubly Charmed Baryon Xi_cc^+
We observe a signal for the doubly charmed baryon Xi_cc^+ in the charged
decay mode Xi_cc^+ --> Lambda_c^+ K- pi+ in data from SELEX, the charm
hadro-production experiment at Fermilab. We observe an excess of 15.9 events
over an expected background of 6.1 +/- 0.5 events, a statistical significance
of 6.3sigma. The observed mass of this state is (3519 +/- 1) MeV/c^2. The
Gaussian mass width of this state is 3MeV/c^2, consistent with resolution; its
lifetime is less than 33fsec at 90% confidence.Comment: 5 pages, 3 figures, accepted for publication in Physical Review
Letter
First Measurement of pi e -> pi e gamma Pion Virtual Compton Scattering
Pion Virtual Compton Scattering (VCS) via the reaction pi e --> pi e gamma
was observed in the Fermilab E781 SELEX experiment. SELEX used a 600 GeV/c pi-
beam incident on target atomic electrons, detecting the incident pi- and the
final state pi-, electron and gamma. Theoretical predictions based on chiral
perturbation theory are incorporated into a Monte Carlo simulation of the
experiment and are compared to the data. The number of reconstructed events (9)
and their distribution with respect to the kinematic variables (for the
kinematic region studied) are in reasonable accord with the predictions. The
corresponding pi- VCS experimental cross section is sigma=38.8+-13 nb, in
agreement with the theoretical expectation sigma=34.7 nb.Comment: 10 pages, 12 figures, 4 tables, 25 references, SELEX home page is
http://fn781a.fnal.gov/, revised July 21, 2002 in response to journal referee
Comment
Observation of the Cabibbo-suppressed decay Xi_c+ -> p K- pi+
We report the first observation of the Cabibbo-suppressed charm baryon decay
Xi_c+ -> p K- pi+. We observe 150 +- 22 events for the signal. The data were
accumulated using the SELEX spectrometer during the 1996-1997 fixed target run
at Fermilab, chiefly from a 600 GeV/c Sigma- beam. The branching fractions of
the decay relative to the Cabibbo-favored Xi_c+ -> Sigma+ K- pi+ and Xi_c+ ->
X- pi+ pi+ are measured to be B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> Sigma+ K- pi+) =
0.22 +- 0.06 +- 0.03 and B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> X- pi+ pi+) = 0.20 +-
0.04 +- 0.02, respectively.Comment: 5 pages, RevTeX, 3 figures (postscript), Submitted to Phys. Rev. Let
First observation of a narrow charm-strange meson DsJ(2632) -> Ds eta and D0 K+
We report the first observation of a charm-strange meson DsJ(2632) at a mass
of 2632.6+/-1.6 MeV/c^2 in data from SELEX, the charm hadro-production
experiment E781 at Fermilab. This state is seen in two decay modes, Ds eta and
D0 K+. In the Ds eta decay mode we observe an excess of 49.3 events with a
significance of 7.2sigma at a mass of 2635.9+/-2.9 MeV/c^2. There is a
corresponding peak of 14 events with a significance of 5.3sigma at 2631.5+/-1.9
MeV/c^2 in the decay mode D0 K+. The decay width of this state is <17 MeV/c^2
at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(Dseta)
is 0.16+/-0.06. The mechanism which keeps this state narrow is unclear. Its
decay pattern is also unusual, being dominated by the Ds eta decay mode.Comment: 5 pages, 3 included eps figures. v2 as accepted for publication by
PR
Measurement of Semileptonic Branching Fractions of B Mesons to Narrow D** States
Using the data accumulated in 2002-2004 with the DO detector in
proton-antiproton collisions at the Fermilab Tevatron collider with
centre-of-mass energy 1.96 TeV, the branching fractions of the decays B ->
\bar{D}_1^0(2420) \mu^+ \nu_\mu X and B -> \bar{D}_2^{*0}(2460) \mu^+ \nu_\mu X
and their ratio have been measured: BR(\bar{b}->B) \cdot BR(B-> \bar{D}_1^0
\mu^+ \nu_\mu X) \cdot BR(\bar{D}_1^0 -> D*- pi+) =
(0.087+-0.007(stat)+-0.014(syst))%; BR(\bar{b}->B)\cdot BR(B->D_2^{*0} \mu^+
\nu_\mu X) \cdot BR(\bar{D}_2^{*0} -> D*- \pi^+) =
(0.035+-0.007(stat)+-0.008(syst))%; and (BR(B -> \bar{D}_2^{*0} \mu^+ \nu_\mu
X)BR(D2*0->D*- pi+)) / (BR(B -> \bar{D}_1^{0} \mu^+ \nu_\mu X)\cdot
BR(\bar{D}_1^{0}->D*- \pi^+)) = 0.39+-0.09(stat)+-0.12(syst), where the charge
conjugated states are always implied.Comment: submitted to Phys. Rev. Let
Measurement of the Lifetime Difference in the B_s^0 System
We present a study of the decay B_s^0 -> J/psi phi We obtain the CP-odd
fraction in the final state at time zero, R_perp = 0.16 +/- 0.10 (stat) +/-
0.02 (syst), the average lifetime of the (B_s, B_sbar) system, tau (B_s^0)
=1.39^{+0.13}_{-0.16} (stat) ^{+0.01}_{-0.02} (syst) ps, and the relative width
difference between the heavy and light mass eigenstates, Delta Gamma/Gamma =
(Gamma_L - Gamma_H)/Gamma =0.24^{+0.28}_{-0.38} (stat) ^{+0.03}_{-0.04} (syst).
With the additional constraint from the world average of the B_s^0$lifetime
measurements using semileptonic decays, we find tau (B_s^0)= 1.39 +/- 0.06 ~ps
and Delta Gamma/\Gamma = 0.25^{+0.14}_{-0.15}. For the ratio of the B_s^0 and
B^0 lifetimes we obtain tau(B_s^0)/tau(B^0)} = 0.91 +/- 0.09 (stat) +/- 0.003
(syst).Comment: submitted to Phys. Rev. Lett. FERMILAB-PUB-05-324-
Search for R-parity violating supersymmetry via the LLE couplings lambda_{121}, lambda_{122} or lambda_{133} in ppbar collisions at sqrt(s)=1.96 TeV
A search for gaugino pair production with a trilepton signature in the
framework of R-parity violating supersymmetry via the couplings lambda_121,
lambda_122, or lambda_133 is presented. The data, corresponding to an
integrated luminosity of L~360/pb, were collected from April 2002 to August
2004 with the D0 detector at the Fermilab Tevatron Collider, at a
center-of-mass energy of sqrt(s)=1.96 TeV. This analysis considers final states
with three charged leptons with the flavor combinations eel, mumul, and eetau
(l=e or mu). No evidence for supersymmetry is found and limits at the 95%
confidence level are set on the gaugino pair production cross section and lower
bounds on the masses of the lightest neutralino and chargino are derived in two
supersymmetric models.Comment: 9 pages, 4 figures (fig2 includes 3 subfigures
Search for Large Extra Spatial Dimensions in Dimuon Production with the D0 Detector
We present the results of a search for the effects of large extra spatial
dimensions in collisions at 1.96 TeV in events
containing a pair of energetic muons. The data correspond to 246 \ipb of
integrated luminosity collected by the \D0 experiment at the Fermilab Tevatron
Collider. Good agreement with the expected background was found, yielding no
evidence for large extra dimensions. We set 95% C.L. lower limits on the
fundamental Planck scale between 0.85 TeV and 1.27 TeV within several
formalisms. These are the most stringent limits achieved in the dimuon channel
to date.Comment: 8 pages, 3 figures, 1 table. Published in Phys. Rev. Lett. Minor
changes in v2 to match the published versio
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