84 research outputs found
Rapid malignant progression of an intraparenchymal choroid plexus papillomas
Background: Choroid plexus tumors (CPTs) are rare neoplasms accounting for only 0.3-0.6% of all brain tumors in adults and 2-5% in children. The World Health Organization (WHO) classification describes three histological grades: grade I is choroid plexus papilloma (CPP), grade II is atypical papilloma, and grade III is the malignant form of carcinoma. In adults, CPTs rarely have a supratentorial localization. Case Description: Here we report a very rare case of an intraparenchymal parietal CPP with a rapid histological transition from grade I to grade III WHO in a 67-year-old man, in <7 months. Conclusion: Because of the rarity of these oncotypes, descriptions of each new case are useful, mostly to consider this diagnostic entity in extraventricular brain tumors of adults, despite an unusual location
Nuclear moments for the neutrinoless double beta decay II
The recently developed formalism for the evaluation of nuclear form factors
in neutrinoless double beta decay is applied to , ,
, , and nuclei. Explicit analytical
expressions that follows from this theoretical development, in the single mode
model for the decay of , have been worked out. They are useful both
for testing the full numerical calculations, and for analytically checking the
consistency with other formalisms. Large configuration space calculations are
compared with previous studies, where alternative formulations were used. Yet,
besides using the G-matrix as residual interaction, we here use a simple
-force. Attention is paid to the connected effects of the short range
nuclear correlations and the finite nucleon size. Constraints on lepton number
violating terms in the weak Hamiltonian (effective neutrino Majorana mass and
effective right-handed current coupling strengths) are deduced.Comment: 18 pages, latex, minor changes, to appear in Nucl. Phys.
A Cryogenic Underground Observatory for Rare Events: Cuore, an Update
CUORE is a proposed tightly packed array of 1000 TeO_{2} bolometers, each
being a cube 5 cm on a side with a mass of 750 gms. The array consists of 25
vertical towers, arranged in a square, of 5 towers by 5 towers, each containing
10 layers of 4 crystals. The design of the detector is optimized for ultralow-
background searches for neutrinoless double beta decay of ^{130}Te (33.8%
abundance), cold dark matter, solar axions, and rare nuclear decays. A
preliminary experiment involving 20 crystals of various sizes (MIBETA) has been
completed, and a single CUORE tower is being constructed as a smaller scale
experiment called CUORICINO. The expected performance and sensitivity, based on
Monte Carlo simulations and extrapolations of present results, are reported.Comment: in press: Nucl. Phys. of Russian Academy of Sc
Measurement of the response of heat-and-ionization germanium detectors to nuclear recoils
The heat quenching factor Q' (the ratio of the heat signals produced by
nuclear and electron recoils of equal energy) of the heat-and-ionization
germanium bolometers used by the EDELWEISS collaboration has been measured. It
is explained how this factor affects the energy scale and the effective
quenching factor observed in calibrations with neutron sources. This effective
quenching effect is found to be equal to Q/Q', where Q is the quenching factor
of the ionization yield. To measure Q', a precise EDELWEISS measurement of Q/Q'
is combined with values of Q obtained from a review of all available
measurements of this quantity in tagged neutron beam experiments. The
systematic uncertainties associated with this method to evaluate Q' are
discussed in detail. For recoil energies between 20 and 100 keV, the resulting
heat quenching factor is Q' = 0.91+-0.03+-0.04, where the two errors are the
contributions from the Q and Q/Q' measurements, respectively. The present
compilation of Q values and evaluation of Q' represent one of the most precise
determinations of the absolute energy scale for any detector used in direct
searches for dark matter.Comment: 28 pages, 7 figures. Submitted to Phys. Rev.
Aqueous Humor Analysis in Overlapping Clinical Diagnosis of Cytomegalovirus and Rubella Virus Anterior Uveitis
Background and Objectives: A cross-sectional single-center study was conducted to investigate the etiology in hypertensive anterior uveitis whose clinical features are not fully distinctive from cytomegalovirus or from rubella virus and to demonstrate the possible coexistence of both these viruses in causing anterior uveitis. Materials and Methods: The clinical charts of a cohort of patients with hypertensive viral anterior uveitis of uncertain origin consecutively seen in a single center from 2019 to 2022 were retrospectively reviewed; data on the clinical features, aqueous polymerase chain reaction, and antibody response to cytomegalovirus and rubella virus were collected. Results: Forty-three eyes of as many subjects with viral anterior uveitis of uncertain origin were included. Thirty-two patients had an aqueous polymerase chain reaction or antibody index positive to cytomegalovirus only, while 11 cases had an aqueous antibody response to both cytomegalovirus and rubella virus. This latter overlapping group had a statistically significant higher rate of hypochromia and anterior vitritis (p-value: 0.02 and < 0.001, respectively). Conclusions: The simultaneous presence of intraocular antibodies against cytomegalovirus and rubella virus could redefine the differential diagnosis of hypertensive viral anterior uveitis, demonstrating a possible "converged" immune pathway consisting in a variety of stimuli
Peripheral facial palsy following ventriculoperitoneal shunt. The lesson we have learned
The most frequent complications after shunt surgery are infective and obstructive. Other types are less common, and eventually occur due to technical errors during brain ventricular puncture, opening the intraperitoneal cavity or the tunnelling of the catheter between the two points. Although rare, there are well-reported complications related to the poor positioning of the distal catheter, with perforation of organs and tissues. We report a very rare case of a male patient with normal pressure hydrocephalus submitted to ventriculoperitoneal shunt. During tunnelling of the shunt stylet, a peripheral facial palsy due to injury to the extra cranial segment of the facial nerve occurred. To the best of our knowledge this is the second case described in Literature. The patient and the surgeon should be aware of this very rare but possible complication in shunt surgery being careful to the course of the facial nerve in the mastoid region
ZnMoO4: a promising bolometer for neutrinoless double beta decay searches
We investigate the performances of two ZnMoO4 scintillating crystals operated
as bolometers, in view of a next generation experiment to search the
neutrinoless double beta decay of Mo-100. We present the results of the alpha
vs beta/gamma discrimination, obtained through the scintillation light as well
as through the study of the shape of the thermal signal alone. The
discrimination capability obtained at the 2615 keV line of Tl-208 is 8 sigma,
using the heat-light scatter plot, while it exceeds 20 sigma using the shape of
the thermal pulse alone. The achieved FWHM energy resolution ranges from 2.4
keV (at 238 keV) to 5.7 keV (at 2615 keV). The internal radioactive
contaminations of the ZnMoO4 crystals were evaluated through a 407 hours
background measurement. The obtained limit is < 32 microBq/kg for Th-228 and
Ra-226. These values were used for a Monte Carlo simulation aimed at evaluating
the achievable background level of a possible, future array of enriched ZnMoO4
crystals.Comment: 9 pages, 8 figure
Neutrinoless Double Beta Decay within QRPA with Proton-Neutron Pairing
We have investigated the role of proton-neutron pairing in the context of the
Quasiparticle Random Phase approximation formalism. This way the neutrinoless
double beta decay matrix elements of the experimentally interesting A= 48, 76,
82, 96, 100, 116, 128, 130 and 136 systems have been calculated. We have found
that the inclusion of proton-neutron pairing influences the neutrinoless double
beta decay rates significantly, in all cases allowing for larger values of the
expectation value of light neutrino masses. Using the best presently available
experimental limits on the half life-time of neutrinoless double beta decay we
have extracted the limits on lepton number violating parameters.Comment: 16 RevTex page
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