4,947 research outputs found
Experimental observation of optical rotation generated in vacuum by a magnetic field
We report the experimental observation of a light polarization rotation in
vacuum in the presence of a transverse magnetic field. Assuming that data
distribution is Gaussian, the average measured rotation is (3.9+/-0.5)e-12
rad/pass, at 5 T with 44000 passes through a 1m long magnet, with lambda = 1064
nm. The relevance of this result in terms of the existence of a light, neutral,
spin-zero particle is discussed.Comment: 11 pages, 4 figures, submitted to Physical Review Letters Comment to
version 2: minor changes to abstract and final discussion. Added 2 references
Comment to version 3: corrected minor typographical errors, eliminated the
distinction between scalar and pseudoscalar in the particle interpretation of
the resul
Towards a direct measurement of vacuum magnetic birefringence: PVLAS achievements
Nonlinear effects in vacuum have been predicted but never observed yet
directly. The PVLAS collaboration has long been working on an apparatus aimed
at detecting such effects by measuring vacuum magnetic birefringence.
Unfortunately the sensitivity has been affected by unaccounted noise and
systematics since the beginning. A new small prototype ellipsometer has been
designed and characterized at the Department of Physics of the University of
Ferrara, Italy entirely mounted on a single seismically isolated optical bench.
With a finesse F = 414000 and a cavity length L = 0.5 m we have reached the
predicted sensitivity of psi = 2x10^-8 1/sqrt(Hz) given the laser power at the
output of the ellipsomenter of P = 24 mW. This record result demonstrates the
feasibility of reaching such sensitivities and opens the way to designing a
dedicated apparatus for a first detection of vacuum magnetic birefringence
A real-time RT-PCR assay for molecular identiïŹcation and quantitation of feline morbillivirus RNA from biological specimens.
The aim of this study was to develop a real-time RT-PCR to detect and quantitate feline
morbillivirus (FeMV) RNA in biological samples. Primers and probe were targeted on a conserved
region of FeMV P/V/C gene. To validate the assay with field samples, a total number of specimens
of cats have been recruited including 264 urine and blood samples and compared with a generic
RT-PCR targeting the L protein encoding gene of morbilliviruses. In addition, 385 tissue samples
from 35 carcasses of cats have been also employed. RNA titres were low in all tested samples.
Results also indicated the absence of cross-reaction with related morbilliviruses and existing
pathogens of cats. However, in tissues with low levels of FeMV RNA, the presence of viral antigen
was confirmed by immunohistochemistry targeting the N viral protein. This newly described assay
allows for a rapid, accurate and reliable quantitative detection of FeMV RNA that can be applied
for diagnostics and research studies
Efficacy and safety profile of a novel technique, ThuLEP (Thulium laser enucleation of the prostate) for the treatment of benign prostate hypertrophy. Our experience on 148 patients.
BACKGROUND: Over the past years laser technology has played a predominant role in prostate surgery, for the treatment of benign prostate hypertrophy (BPH). Various laser devices have been introduced in clinical practice, showing good results in terms of complications and urodynamic outcomes efficacy compared with TURP and Open Prostatectomy. In this study we describe the efficacy and the safety profile of a novel laser technique, ThuLEP (Thulium Laser Enucleation of Prostate) that permits a complete anatomical endoscopic enucleation of prostatic adenoma independently to prostate size. METHODS: 148 patients with a mean age of 68.2 years were enrolled between September 2009 and March 2012 (36 months), and treated for BPH with ThuLEP. Every patient was evaluated at base line according to: Digital Rectal Examination (DRE), prostate volume, Post-Voided volume (PVR), International Prostate Symptoms Score (I-PSS), International Index of Erectile Function-5 (IIEF-5), Quality of Life (QoL), PSA values, urine analysis and urine culture, uroflowmetry. The same evaluation was conducted after a 12 month follow-up. ThuLEP was performed by 2 expert surgeons. RESULTS: Our data showed a better post-operative outcome in terms of catheter removal, blood loss, TURP syndrome, clot retention and residual tissue compared to large series of TURP and OP. Only 1.3% of patients had bladder wall injury during morcellation. I-PSS, Qmax, Prostate Volume, QoL and PVR showed a highly significant improvement at 12 month follow-up in comparison to preoperative assessment. CONCLUSION: ThuLEP represent an innovative option in patients with BPH. It is a size independent surgical endoscopic technique and it can be considered the real alternative, at this time, to TURP and even more to Open Prostatectomy for large prostate, with a complete removal of adenoma and with a low complication rate
The gamma-ray burst monitor for Lobster-ISS
Lobster-ISS is an X-ray all-sky monitor experiment selected by ESA two years
ago for a Phase A study (now almost completed) for a future flight (2009)
aboard the Columbus Exposed Payload Facility of the International Space
Station. The main instrument, based on MCP optics with Lobster-eye geometry,
has an energy passband from 0.1 to 3.5 keV, an unprecedented daily sensitivity
of 2x10^{-12} erg cm^{-2}s$^{-1}, and it is capable to scan, during each orbit,
the entire sky with an angular resolution of 4--6 arcmin. This X-ray telescope
is flanked by a Gamma Ray Burst Monitor, with the minimum requirement of
recognizing true GRBs from other transient events. In this paper we describe
the GRBM. In addition to the minimum requirement, the instrument proposed is
capable to roughly localize GRBs which occur in the Lobster FOV (162x22.5
degrees) and to significantly extend the scientific capabilities of the main
instrument for the study of GRBs and X-ray transients. The combination of the
two instruments will allow an unprecedented spectral coverage (from 0.1 up to
300/700 keV) for a sensitive study of the GRB prompt emission in the passband
where GRBs and X-Ray Flashes emit most of their energy. The low-energy spectral
band (0.1-10 keV) is of key importance for the study of the GRB environment and
the search of transient absorption and emission features from GRBs, both goals
being crucial for unveiling the GRB phenomenon. The entire energy band of
Lobster-ISS is not covered by either the Swift satellite or other GRB missions
foreseen in the next decade.Comment: 6 pages, 4 figures. Paper presented at the COSPAR 2004 General
Assembly (Paris), accepted for publication in Advances in Space Research in
June 2005 and available on-line at the Journal site
(http://www.sciencedirect.com/science/journal/02731177), section "Articles in
press
Testosterone deficiency causes penile fibrosis and organic erectile dysfunction in aging men. Evaluating association among Age, TDS and ED.
INTRODUCTION: We studied the possible correlation between age, testosterone deficiency, cavernosal fibrosis and erectile dysfunction (ED). METHODS: 47 patients with ED were enrolled between September 2010 and October 2011. IIEF-EF score, NPTR test using the Rigiscan method, total and free testosterone levels, and cavernosum biopsy were carried out on all patients. Patients aged 65 or over were defined as Old Age (OA) while patients under 65 were defined Young age (YA). The strength of the relationships found was estimated by Odds Ratio. RESULTS: 74% of patients with values of over 52% collagen fibers in the corpora cavernosa were found to have organic ED. A significant difference was found in age, percentage of collagen fibers, testosterone levels between patients with Positive Rigiscan (PR) and Negative Rigiscan (NR). Hypotestosteronaemia increased the risk of ED with PR (OR: 21.4, 95% CI: 20.2-22.6) and in both young age patients (OR: 4.3, 95% CI: 2.4-6.2) and old age patients (OR: 15.5, 95% CI: 13.4-17.6). Moreover cavernosal fibrosis increased the risk of ED with PR in both young age patients (OR: 8.2, 95% CI: 6.4-10.0 and old age patients (OR: 24.6, 95% CI: 20.8-28.4). CONCLUSIONS: This study demonstrates a strong association among age, testosterone deficiency, cavernosal fibrosis and ED with PR. Age, testosterone deficiency and cavernosal fibrosis are potentially correctable factors of cavernosal fibrosis and organic ED. Further, prospective studies are needed to evaluate if testosterone treatment, alone or in association with PDE5 inhibitors, may lower the risk of cavernosal fibrosis or decrease the severity the fibrosis in ED patients
Limits on Low Energy Photon-Photon Scattering from an Experiment on Magnetic Vacuum Birefringence
Experimental bounds on induced vacuum magnetic birefringence can be used to
improve present photon-photon scattering limits in the electronvolt energy
range. Measurements with the PVLAS apparatus (E. Zavattini {\it et al.}, Phys.
Rev. D {\bf77} (2008) 032006) at both nm and 532 nm lead to
bounds on the parameter {\it A}, describing non linear effects in QED, of
T @ 1064 nm and T @ 532 nm, respectively, at 95% confidence level,
compared to the predicted value of T. The
total photon-photon scattering cross section may also be expressed in terms of
, setting bounds for unpolarized light of m and m. Compared to the expected QED scattering cross
section these results are a factor of higher and represent
an improvement of a factor about 500 on previous bounds based on ellipticity
measurements and of a factor of about on bounds based on direct
stimulated scattering measurements
Charged particle's flux measurement from PMMA irradiated by 80 MeV/u carbon ion beam
Hadrontherapy is an emerging technique in cancer therapy that uses beams of
charged particles. To meet the improved capability of hadrontherapy in matching
the dose release with the cancer position, new dose monitoring techniques need
to be developed and introduced into clinical use. The measurement of the fluxes
of the secondary particles produced by the hadron beam is of fundamental
importance in the design of any dose monitoring device and is eagerly needed to
tune Monte Carlo simulations. We report the measurements done with charged
secondary particles produced from the interaction of a 80 MeV/u fully stripped
carbon ion beam at the INFN Laboratori Nazionali del Sud, Catania, with a
Poly-methyl methacrylate target. Charged secondary particles, produced at
90 with respect to the beam axis, have been tracked with a drift
chamber, while their energy and time of flight has been measured by means of a
LYSO scintillator. Secondary protons have been identified exploiting the energy
and time of flight information, and their emission region has been
reconstructed backtracking from the drift chamber to the target. Moreover a
position scan of the target indicates that the reconstructed emission region
follows the movement of the expected Bragg peak position. Exploting the
reconstruction of the emission region, an accuracy on the Bragg peak
determination in the submillimeter range has been obtained. The measured
differential production rate for protons produced with 83 MeV and emitted at 90 with respect to the beam line is: .Comment: 13 pages, 9 figure
New PVLAS results and limits on magnetically induced optical rotation and ellipticity in vacuum
IIn 2006 the PVLAS collaboration reported the observation of an optical
rotation generated in vacuum by a magnetic field. To further check against
possible instrumental artifacts several upgrades to the PVLAS apparatus have
been made during the last year. Two data taking runs, at the wavelength of 1064
nm, have been performed in the new configuration with magnetic field strengths
of 2.3 T and 5 T. The 2.3 T field value was chosen in order to avoid stray
fields. The new observations do not show the presence of a rotation signal down
to the levels of rad at 5 T and rad at
2.3 T (at 95% c.l.) with 45000 passes in the magnetic field zone. In the same
conditions no ellipticity signal was detected down to at 2.3
T (at 95% c.l.), whereas at 5 T a signal is still present. The physical nature
of this ellipticity as due to an effect depending on can be excluded by
the measurement at 2.3 T. These new results completely exclude the previously
published magnetically induced vacuum dichroism results, indicating that they
were instrumental artifacts. These new results therefore also exclude the
particle interpretation of the previous PVLAS results as due to a spin zero
boson. The background ellipticity at 2.3 T can be used to determine a new limit
on the total photon-photon scattering cross section of barn at 95% c.l..Comment: 25 pages, 7 figures Main changes rel. to v.2: minor changes to
abstract, replaced Figures 4,5,6, corrected typographical errors. Paper
submitted to Physical Review
Mechanical and electrical noise in the PVLAS experiment
PVLAS is an experiment which aims at the direct detection of photon-field
scattering: it employs optical methods and a large rotating superconducting
magnet, and its large, compact structure is affected by both mechanical and
electrical noises. This paper introduces briefly the data analysis methods used
in the experiment and summarizes the mechanical and electrical noise situation.Comment: 8 pages, 14 figures, PDF only, talk given by E. Milotti at the QNDE
2002 conference, Bellingham (WA), July 14-19 200
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