270 research outputs found
Late Relapse and Follow-up Protocols in Testicular Germ Cell Tumours: The Edinburgh Cancer Centre Experience and Review of the Literature
Aims To identify clinicopathological features and outcomes in patients with late relapse (LR) of testicular germ cell tumours (GCTs) in order to guide follow-up policy. Materials and Methods The Edinburgh Cancer Centre (ECC) database identified all patients diagnosed with testicular GCT between 1988 and 2002. Of 703 patients, six relapsed more than 24 months after their initial treatment. A retrospective casenote review was performed to extract clinical, pathological, treatment and outcome data. Results Six patients (0.85%) underwent late relapse. All patients presented initially with stage I disease and five were classified as good risk (International Germ Cell Consensus Classification, IGCCC). Median time to LR was 31 months. Two patients had previously relapsed less than 24 months from initial diagnosis. Markers at the time of relapse were normal in all patients. In all cases of late relapse disease was confined to axial lymphadenopathy. Three patients were treated with chemotherapy alone, two patients underwent surgical resection and one patient received combined treatment. All patients obtained a complete response and all remain disease free with a median follow-up of 52 months. Conclusions The incidence of late relapse in this series is low. Chemo-naive patients with LR were successfully salvaged with chemotherapy alone and patients previously exposed to cisplatin-based chemotherapy were salvaged with complete surgical excision. The optimal length of follow-up in patients with testicular germ cell tumours is not known and practice varies widely. In this cohort of 703 patients, only one patient who relapsed was picked up by additional clinic follow-up between 5 and 10 years. Thus, on the basis of this small series, the authors suggest that follow-up after five years may not be justified
Factorizing the hard and soft spectator scattering contributions for the nucleon form factor F_1 at large Q^2
We investigate the soft spectator scattering contribution for the FF .
We focus our attention on factorization of the hard-collinear scale corresponding to transition from SCET-I to SCET-II. We compute the
leading order jet functions and find that the convolution integrals over the
soft fractions are logarithmically divergent. This divergency is the
consequence of the boost invariance and does not depend on the model of the
soft correlation function describing the soft spectator quarks. Using as
example a two-loop diagram we demonstrated that such a divergency corresponds
to the overlap of the soft and collinear regions. As a result one obtains large
rapidity logarithm which must be included in the correct factorization
formalism. We conclude that a consistent description of the factorization for
implies the end-point collinear divergencies in the hard and soft
spectator contributions, i.e. convolution integrals with respect to collinear
fractions are not well-defined. Such scenario can only be realized when the
twist-3 nucleon distribution amplitude has specific end-point behavior which
differs from one expected from the evolution of the nucleon distribution
amplitude. Such behavior leads to the violation of the collinear factorization
for the hard spectator scattering contribution. We suggest that the soft
spectator scattering and chiral symmetry breaking provide the mechanism
responsible for the violation of collinear factorization in case of form factor
.Comment: 25 pages, 6 figures, text is improved, few typos corrected, one
figure added, statement about end-point behavior of the nucleon DA is
formulated more accuratel
Dimeric FcÎłR ectodomains detect pathogenic anti-platelet factor 4-heparin antibodies in heparin-induced thromobocytopenia
Background
Heparinâinduced thrombocytopenia (HIT) is a major and potentially fatal consequence of antibodies produced against platelet factor 4 (PF4)âheparin complexes following heparin exposure. Not all antiâPF4âheparin antibodies are pathogenic, so overdiagnosis can occur, with resulting inappropriate use of alternative anticoagulation therapies that have associated risks of bleeding. However, definitive platelet functional assays are not widely available for routine analysis.
Objectives
To assess the utility of dimeric recombinant soluble FcÎłRIIa (rsFcÎłRIIa) ectodomains for detecting HIT antibodies.
Patients/Methods
Plasma from 27 suspected HIT patients were tested for pathogenic antiâPF4âheparin antibodies by binding of a novel dimeric FcÎłRIIa ectodomain probe. Plasmas were also tested by the use of PF4âheparin IgG ELISA, the HemosIL AcuStar HIT IgGâspecific assay, and a serotonin release assay (SRA).
Results
The dimeric rsFcÎłRIIa test produced no false positives and excluded four samples that were positive by IgG ELISA. In this small patient cohort, the novel assay correctly assigned 93% of the suspected HIT patients, with two of the HIT patients being scored as false negatives. The improved discrimination of the novel assay over the IgG ELISA, which scored four false positives, supports the mechanistic interpretation that binding of dimeric rsFcÎłRIIa detects pairs of closely spaced IgG antibodies in PF4âheparin immune complexes.
Conclusions
This study found the cellâfree, functionâbased dimeric rsFcÎłRIIa assay to be convenient, simple, and potentially predictive of HIT. The assay had improved specificity over the IgG ELISA, and correlated strongly with the AcuStar HIT IgGâspecific assay, warranting further evaluation of its potential to identify HIT in larger patient cohorts
External Electromagnetic Fields of a Slowly Rotating Magnetized Star with Gravitomagnetic Charge
We study Maxwell equations in the external background spacetime of a slowly
rotating magnetized NUT star and find analytical solutions for the exterior
electric fields after separating the equations of electric field into angular
and radial parts in the lowest order approximation. The star is considered
isolated and in vacuum, with dipolar magnetic field aligned with the axis of
rotation. The contribution to the external electric field of star from the NUT
charge is considered in detail.Comment: 6 pages, 2 figures, accepted for publication in Astrophysics and
Space Scienc
Searching for chiral logs in the static-light decay constant
Using the clover fermion action in unquenched QCD with pion masses as low as
420 MeV, we look for evidence for chiral logs in the static-light decay
constant. There is some evidence for a chiral log term, if the original static
theory of Eichten and Hill is used. However, the more precise data from the
static action of the ALPHA collaboration do not show any evidence for
non-linear dependence of the static-light decay constant on the light quark
mass. We make some comments on the connection between chiral perturbation
theory for decay constants of the pion and static-light meson
A wider Europe? The view from Russia, Belarus and Ukraine
On the evidence of national surveys conducted between 2000 and 2006, there is a declining sense of European self-identity in the three Slavic post-Soviet republics of Russia, Belarus and Ukraine. Attitudes towards the European Union and the possibility of membership are broadly supportive, but with a substantial proportion who find it difficult to express a view, and substantial proportions are poorly informed in comparison with the general public in EU member or prospective member countries. Those who are better informed are more likely to favour EU membership and vice versa. Generally, socioeconomic characteristics (except for age and region) are relatively poor predictors of support for EU membership as compared with attitudinal variables. But âEuropeannessâ should not be seen as a given, and much will depend on whether EU member countries emphasize what is common to east and west or establish ânew dividing linesâ in place of those of the cold war
Adjoint "quarks" on coarse anisotropic lattices: Implications for string breaking in full QCD
A detailed study is made of four dimensional SU(2) gauge theory with static
adjoint ``quarks'' in the context of string breaking. A tadpole-improved action
is used to do simulations on lattices with coarse spatial spacings ,
allowing the static potential to be probed at large separations at a
dramatically reduced computational cost. Highly anisotropic lattices are used,
with fine temporal spacings , in order to assess the behavior of the
time-dependent effective potentials. The lattice spacings are determined from
the potentials for quarks in the fundamental representation. Simulations of the
Wilson loop in the adjoint representation are done, and the energies of
magnetic and electric ``gluelumps'' (adjoint quark-gluon bound states) are
calculated, which set the energy scale for string breaking. Correlators of
gauge-fixed static quark propagators, without a connecting string of spatial
links, are analyzed. Correlation functions of gluelump pairs are also
considered; similar correlators have recently been proposed for observing
string breaking in full QCD and other models. A thorough discussion of the
relevance of Wilson loops over other operators for studies of string breaking
is presented, using the simulation results presented here to support a number
of new arguments.Comment: 22 pages, 14 figure
Pulsar kicks from a dark-matter sterile neutrino
We show that a sterile neutrino with mass in the 1-20 keV range and a small
mixing with the electron neutrino can simultaneously explain the origin of the
pulsar motions and the dark matter in the universe. An asymmetric neutrino
emission from a hot nascent neutron star can be the explanation of the observed
pulsar velocities. In addition to the pulsar kick mechanism based on resonant
neutrino transitions, we point out a new possibility: an asymmetric
off-resonant emission of sterile neutrinos. The two cases correspond to
different values of the masses and mixing angles. In both cases we identify the
ranges of parameters consistent with the pulsar kick, as well as cosmological
constraints.Comment: 5 pages, 2 figures; final version; discussion and references adde
Matter degrees of freedom and string breaking in Abelian projected quenched SU(2) QCD
In the Abelian projection the Yang--Mills theory contains Abelian gauge
fields (diagonal degrees of freedom) and the Abelian matter fields
(off-diagonal degrees) described by a complicated action. The matter fields are
essential for the breaking of the adjoint string. We obtain numerically the
effective action of the Abelian gauge and the Abelian matter fields in quenched
SU(2) QCD and show that the Abelian matter fields provide an essential
contribution to the total action even in the infrared region. We also observe
the breaking of an Abelian analog of the adjoint string using Abelian
operators. We show that the adjoint string tension is dominated by the Abelian
and the monopole contributions similarly to the case of the fundamental
particles. We conclude that the adjoint string breaking can successfully be
described in the Abelian projection formalism.Comment: 16 pages, 10 figures, 2 table
Lattice QCD Simulations in External Background Fields
We discuss recent results and future prospects regarding the investigation,
by lattice simulations, of the non-perturbative properties of QCD and of its
phase diagram in presence of magnetic or chromomagnetic background fields.
After a brief introduction to the formulation of lattice QCD in presence of
external fields, we focus on studies regarding the effects of external fields
on chiral symmetry breaking, on its restoration at finite temperature and on
deconfinement. We conclude with a few comments regarding the effects of
electromagnetic background fields on gluodynamics.Comment: 31 pages, 10 figures, minor changes and references added. To appear
in Lect. Notes Phys. "Strongly interacting matter in magnetic fields"
(Springer), edited by D. Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Ye
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