252 research outputs found
Molecular Cytogenetic Analysis of Spitz Nevi Shows Clear Differences to Melanoma
Spitz nevus is a benign neoplasm of melanocytes that can be difficult or impossible to distinguish from melanoma by clinical and histopathologic examination. We studied genomic DNA from 17 Spitz nevi by comparative genomic hybridization (CGH). Thirteen lesions showed no chromosomal aberrations, three cases had a gain involving the entire p-arm of chromosome 11, and one case showed a gain of chromosome 7q21-qter. Fluorescence in situ hybridization (FISH) on lesional tissue with a probe for the p-arm of chromosome 11 showed 6–10 p-arm signals per nucleus in those cases with a CGH-detected gain of chromosome 11p. One case with a normal CGH profile also showed increased copy number of 11p by FISH. Thus, the majority of Spitz nevi have a normal chromosomal complement at the level of CGH resolution; however some may contain gains, with 11p apparently being the most frequently involved location. These findings differ significantly from the previously reported changes in primary cutaneous melanoma, which show frequent deletions of chromosomes 9p (82%), 10q (63%), 6q (28%), and 8p (22%), as well as gains of chromosomes 7 (50%), 8 (34%), 6p (28%), 1q (25%) by CGH analysis. These clear differences in the location and frequencies of chromosomal aberrations in Spitz nevi and primary cutaneous melanomas could represent a basis for developing adjunctive techniques for refining accuracy in the difficult differential diagnosis of spitzoid melanocytic neoplasms
How to Read a Visualization Research Paper: Extracting the Essentials
Introduction. Women's sexual pain disorders include dyspareunia and vaginismus and there is need for state-of-the-art information in this area. Aim. To update the scientific evidence published in 2004, from the 2nd International Consultation on Sexual Medicine pertaining to the diagnosis and treatment of women's sexual pain disorders. Methods. An expert committee, invited from six countries by the 3rd International Consultation, was comprised of eight researchers and clinicians from biological and social science disciplines, for the purpose of reviewing and grading the scientific evidence on nosology, etiology, diagnosis, and treatment of women's sexual pain disorders. Main Outcome Measure. Expert opinion was based on grading of evidence-based medical literature, extensive internal committee discussion, public presentation, and debate. Results. A comprehensive assessment of medical, sexual, and psychosocial history is recommended for diagnosis and management. Indications for general and focused pelvic genital examination are identified. Evidence-based recommendations for assessment of women's sexual pain disorders are reviewed. An evidence-based approach to management of these disorders is provided. Conclusions. Continued efforts are warranted to conduct research and scientific reporting on the optimal assessment and management of women's sexual pain disorders, including multidisciplinary approaches. van Lankveld JJDM, Granot M, Weijmar Schultz WCM, Binik YM, Wesselmann U, Pukall CF, Bohm-Starke N, and Achtrari C. Women's sexual pain disorders. J Sex Med 2010;7:615-631
Fluorescence in situ hybridization, a diagnostic aid in ambiguous melanocytic tumors: European study of 113 cases.
Nuclear transparency and effective kaon-nucleon cross section from the A(e, e'K+) reaction
We have determined the transparency of the nuclear medium to kaons from
measurements on C, Cu, and Au targets.
The measurements were performed at the Jefferson Laboratory and span a range in
four-momentum-transfer squared Q=1.1 -- 3.0 GeV. The nuclear
transparency was defined as the ratio of measured kaon electroproduction cross
sections with respect to deuterium, (). We further
extracted the atomic number () dependence of the transparency as
parametrized by and, within a simple model assumption,
the in-medium effective kaon-nucleon cross sections. The effective cross
sections extracted from the electroproduction data are found to be smaller than
the free cross sections determined from kaon-nucleon scattering experiments,
and the parameter was found to be significantly larger than those
obtained from kaon-nucleus scattering. We have included similar comparisons
between pion- and proton-nucleon effective cross sections as determined from
electron scattering experiments, and pion-nucleus and proton-nucleus scattering
data.Comment: 7 pages, 5 figure
Scaling study of the pion electroproduction cross sections and the pion form factor
The H()n cross section was measured for a range of
four-momentum transfer up to =3.91 GeV at values of the invariant
mass, , above the resonance region. The -dependence of the longitudinal
component is consistent with the -scaling prediction for hard exclusive
processes. This suggests that perturbative QCD concepts are applicable at
rather low values of . Pion form factor results, while consistent with the
-scaling prediction, are inconsistent in magnitude with perturbative QCD
calculations. The extraction of Generalized Parton Distributions from hard
exclusive processes assumes the dominance of the longitudinal term. However,
transverse contributions to the cross section are still significant at
=3.91 GeV.Comment: 6 pages, 3 figure
A precise extraction of the induced polarization in the 4He(e,e'p)3H reaction
We measured with unprecedented precision the induced polarization Py in
4He(e,e'p)3H at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2. The induced polarization
is indicative of reaction-mechanism effects beyond the impulse approximation.
Our results are in agreement with a relativistic distorted-wave impulse
approximation calculation but are over-estimated by a calculation with strong
charge-exchange effects. Our data are used to constrain the strength of the
spin independent charge-exchange term in the latter calculation.Comment: submitted to Physical Review Letter
Measurement of Nuclear Transparency for the A(e,e' pi^+) Reaction
We have measured the nuclear transparency of the A(e,e' pi^+) process in
^{2}H,^{12}C, ^{27}Al, ^{63}Cu and ^{197}Au targets. These measurements were
performed at the Jefferson Laboratory over a four momentum transfer squared
range Q^2 = 1.1 - 4.7 (GeV/c)^2. The nuclear transparency was extracted as the
super-ratio of from data to a model of
pion-electroproduction from nuclei without pi-N final state interactions. The
Q^2 and atomic number dependence of the nuclear transparency both show
deviations from traditional nuclear physics expectations, and are consistent
with calculations that include the quantum chromodynamical phenomenon of color
transparency.Comment: 5 pages, 3 figs Changes to figure 2 and 3 (error band updated and
theory curves updated
Probing Quark-Gluon Interactions with Transverse Polarized Scattering
We have extracted QCD matrix elements from our data on double polarized
inelastic scattering of electrons on nuclei. We find the higher twist matrix
element \tilde{d_2}, which arises strictly from quark- gluon interactions, to
be unambiguously non zero. The data also reveal an isospin dependence of higher
twist effects if we assume that the Burkhardt-Cottingham Sum rule is valid. The
fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied
at our low momentum transfer.Comment: formerly "Nachtmann Moments of the Proton and Deuteron Spin Structure
Functions
Proton Spin Structure in the Resonance Region
We have examined the spin structure of the proton in the region of the
nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum
transfer of Q^2 = 1.3 GeV^2. Using the Jefferson Lab polarized electron beam, a
spectrometer, and a polarized solid target, we measured the asymmetries
A_parallel and A_perp to high precision, and extracted the asymmetries A_1 and
A_2, and the spin structure functions g_1 and g_2. We found a notably non-zero
A_perp, significant contributions from higher-twist effects, and only weak
support for polarized quark--hadron duality.Comment: 6 pages, 4 figures, REVTeX4, similar to PRL submission, plots
colorized and appenix added, v3: minor edit, matches PR
Polarization transfer in wide-angle Compton scattering and single-pion photoproduction from the proton
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θpcm=70°. The longitudinal transfer KLL, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ∼3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude
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