Search results for "Sound"

Lymphoscintigraphy with peritumoral injection versus lymphoscintigraphy with subdermal periareolar injection of technetium-labeled human albumin to i…

2014

Background Preoperative lymphoscintigraphy is without doubt a valid method for the detection of the sentinel lymph node (SLN). There has been considerable debate regarding the optimal site for the introduction of the tracer; various sites include peritumoral (PT), periareolar (PA), subdermal, and intradermal injection. Purpose To evaluate retrospectively the lymphoscintigraphic identification rate of peritumoral (PT) injection versus subdermal periareolar (PA) injection in the detection of SLNs in breast cancer. Material and Methods Between October 2002 and December 2011, a cohort of 906 consecutive patients with biopsy proven breast cancer underwent 914 SLN biopsy procedures. A total of 33…

Brain reacts to occasional changes in duration of elements in a continuous sound

1995

In order to study the event-related potential correlates of human ability to detect temporal changes within a continuous sound a sound consisting of two alternating pitches of the same constant duration, with infrequent shortenings of one of the tones, was presented to the subjects. The infrequent shortenings were found to elicit a negative component of the auditory event related potential, called the mismatch negativity (MMN). The experimental parameters were chosen to produce a MMN with a minimal contamination of N1, the main negative deflection of an evoked response with the same latency range as MMN and with a short experimental time. The duration of the whole experiment with three diff…

Fetus acardius: two- and three-dimensional ultrasonographic diagnoses.

2001

Objective. To determine whether ultrasonographic detection of acardiac fetuses and diagnostic accuracy of related malformations improve with complementary use of two-dimensional ultrasonography, three-dimensional ultrasonography, and Doppler scanning. Methods. Three pregnant women with multifetal gestations who were found to have discordant fetuses on initial two-dimensional ultrasonographic scanning were subsequently scanned with three-dimensional ultrasonography and color Doppler ultrasonography. Results. Although the possibility of acardiac fetuses was entertained in all cases after two-dimensional ultrasonographic scanning, the diagnosis was confirmed, and the accuracy and extent of fet…

Involvement of Jugular Valve Insufficiency in Cerebral Venous Air Embolism

2007

Background. Cerebral venous air entrapment is a rare finding on cranial computed tomography (CT) scan. Peripheral air embolism is discussed as a potential cause. However, the mechanism of retrograde passage through internal jugular valves and veins is unclear. Case Report. The case of a patient is reported, who had air entrapment in the left cavernous sinus. Prior to CT scanning, a peripheral intravenous line had been placed. Ultrasound revealed excessive insufficiency of the left internal jugular valve. To further study the mechanism of embolism, an echo contrast agent was injected into the cubital vein. A Valsalva maneuver resulted in retrograde transition of microbubbles across the insuf…

Assessment of endometrial volume by three-dimensional ultrasound prior to embryo transfer: clues to endometrial receptivity

1999

The aim of the present prospective study was to obtain quantitative data on endometrial volume by three-dimensional (3D) ultrasound at the time of embryo transfer in an in-vitro fertilization programme and to assess its value in predicting endometrial receptivity. The cycles (n = 72) were classified according to endometrial volume: group A2 ml, group B 2-4 ml, and group C4 ml. Comparisons of the groups showed that pregnancy and implantation rates were significantly lower (P0.05) in the group of patients with an endometrial volume2 ml. Furthermore, no pregnancy was achieved with an endometrial volume1 ml. It is concluded that endometrial volume by 3D transvaginal ultrasound may become a new …

Uterine effects of metformin administration in anovulatory women with polycystic ovary sindrome

2006

Background Metformin has been shown to improve fertility in anovulatory patients with polycystic ovary syndrome (PCOS), inducing not only a high ovulation and pregnancy rate but also reducing the incidence of miscarriages. The aim of the present study was to evaluate the uterine effects of metformin in patients with PCOS who ovulated under metformin. Methods Thirty-seven non-obese primary infertile anovulatory patients with PCOS and another 30 age- and body mass index-matched healthy women (control group) were studied. PCOS patients were treated with metformin (850 mg twice daily) for 6 months, whereas the control group did not receive any treatment. In these PCOS patients who ovulated whil…

Ultrasound-guided lumbar puncture for nusinersen administration in spinal muscular atrophy patients.

2020

Background and purpose The purpose was to report the results of ultrasound-guided lumbar puncture for the administration of nusinersen in spinal muscular atrophy (SMA) patients with complex spines. Methods Eighteen SMA patients (five children, five adolescents and eight adults) with either severe scoliosis or spondylodesis were evaluated for ultrasound-guided lumbar puncture. Ultrasound was performed with a 3.5 MHz transducer to guide a 22 gauge × 15 mm needle, which was placed in the posterior lumbar space following a parasagittal interlaminar approach. Results Twelve patients had undergone spinal instrumentation (nine growing rods and three spinal fusion) whilst the other six showed sever…

A NUMERICAL APPROACH FOR THE PREDICTION OF SOUND GENERATED BY A MISTUNED ROTOR CASCADE

2012

A numerical investigation on the effects of blade frequency mistuning on the acoustic emission of a rotor cascade in subsonic flow is shown. A numerical method has been developed and implementd to obtain the mistuned rotor aeroelastic response and the associated acoustic waves. Both the aeroelastic and acoustic models are based on a linear unsteady small perturbations theory. The dynamic aeroelastic coupling between bending and torsional responses of each blade and the aerodynamic coupling among the blades are included in the formulation.

PRODROMI SULLE STIME CATASTALI

2012

Comparative analysis of acoustic emission signals generated by electrical discharges measured by the hydrophone and the wideband contact transducer

2005

The paper presents a comparative analysis of the acoustic emission (AE) pulses and signals generated by PDs. For this purpose the measurements of the acoustic emission signals generated by PDs were taken in the multipoint-plane system using a hydrophone placed directly in the area of discharge generation, and the AE pulses using a piezoelectric contact transducer which was on a side wall of a power transformer tub. Next, time runs and amplitude density spectra were drawn. Also the descriptors describing signals in the frequency domain were determined and the time-frequency analysis was carried out, which determined spectrograms for the energy density spectrum.