Search results for "Sound"
showing 10 items of 1845 documents
84 Enhanced Characterization of the Thickness and Bone Mineral Density of the Radius and Tibia by Low-Frequency Guided-Wave Ultrasound
2009
Comparison of ultrasound and bone mineral density assessment of the calcaneus with different regions of interest in healthy early menopausal women.
1998
This study investigated the effect of different sized regions of interest (ROIs) on quantitative ultrasound (QUS) variables of the calcaneus. The effect on QUS of using a fixed ROI as opposed to an ROI adjusted for foot length was also assessed. Eighty Caucasian women, aged 50-57 yr (mean 53 +/- 2) who were healthy and within 0. 5-5 yr of the onset of menopause participated in this study. Using the QUS-1(trade mark) Ultrasonometer (Metra Biosystems, Mountain View, CA), we assessed broadband ultrasound attenuation ([BUA] and UBI-4, dB/MHz), the average transit time through the heel ([TTH], mus) and a multiple-factor index (UBI-4T = UBI-4/TTH, dB/[MHz. mus]). The QUS measurement results were …
Quantitative ultrasound predicts bone mineral density and failure load in human lumbar vertebrae
2006
Quantitative ultrasound is in widespread clinical use for assessment of bone quality at peripheral skeletal sites, but has not yet been applied to those sites in the axial skeleton, such as the spine and hip, where osteoporotic fractures are common.Ultrasound measurements were made in 11 cadaveric vertebrae and relationships with bone mineral density and failure load were investigated. An ultrasonic imaging system was used to measure speed of sound, broadband ultrasonic attenuation, and attenuation at a single frequency, through the vertebral body in the sagittal plane. Ultrasonic measurements were averaged over a region of interest centrally within the vertebral body, and were calculated w…
Noise risk assessment in a bottling plant of a modern Italian winery
2014
In the wine industry, bottling is a phase of the production cycle characterized by high levels of noise, mostly owing to repeated collisions between the bottles. In Italy, the Law Decree 81/2008 defined the requirements for assessing and managing noise risk, identifying a number of procedures to be adopted at different noise levels to limit worker exposure. This study was aimed at evaluating the equivalent and peak noise level inside the bottling plant area of a modern Italian winery. In particular, the influence of the working capacity (number of bottles produced per hour) on noise levels was evaluated. Three test conditions were considered: T1 with a working capacity of 4000 bottles/h; T2…
An efficient functional magnetic resonance imaging data reduction strategy using neighborhood preserving embedding algorithm
2021
High dimensionality data have become common in neuroimaging fields, especially group-level functional magnetic resonance imaging (fMRI) datasets. fMRI connectivity analysis is a widely used, powerful technique for studying functional brain networks to probe underlying mechanisms of brain function and neuropsychological disorders. However, data-driven technique like independent components analysis (ICA), can yield unstable and inconsistent results, confounding the true effects of interest and hindering the understanding of brain functionality and connectivity. A key contributing factor to this instability is the information loss that occurs during fMRI data reduction. Data reduction of high …
Influence of the scalp thickness on the intracranial contribution to rheoencephalography
2004
In spite of the great efforts made by the scientific community, up to now there is no agreement about the rheoencephalography (REG) capability to reflect cerebral blood flow (CBF). Moreover, a standard procedure and the optimal electrode arrangement have not been established yet. In a previous study, we found, using a classical four-shell spherical model of the head and solving it by numerical methods that, theoretically, there could exist an electrode arrangement to register an REG II free of extracranial contribution. In this paper, we have studied the influence of scalp thickness on the intracranial contribution to REG II. The study has been performed by solving the head model, using in …
RUOLO DI S-DETECT, SISTEMA DI SUPPORTO DECISIONALE COMPUTER-ASSISTITO, NELLA CLASSIFICAZIONE BI-RADS DELLE LESIONI FOCALI MAMMARIE: PERFORMANCE DIAGN…
2018
Progressi nella caratterizzazione ecografica bi-rads computer-guidata delle lesioni focali mammarie (LFM)
2018
Confrontare la versione 2.0 (V2) con la versione 1.0 (V1) di un software dedicato di supporto decisionale computer-assistito (S-Detect) nella caratterizzazione delle lesioni focali mammarie (LFM))
Vergleich von Malignitätskriterien in B-Scan- und Farbduplexsonographie mit dem histologischen Erscheinungsbild am Beispiel des experimentell induzie…
2005
BACKGROUND Malignant tumours of the head and the neck are characterised by typical signs of malignancy in greyscale- and colour-coded sonography. Sometimes, such criteria cannot be verified, and in such cases it remains unclear whether typical changes do not exist or whether we just cannot detect them with our high-end ultrasound units. We therefore compared our sonographical findings with the histology obtained in experimentally induced tumours. METHODS Experimental squamous cell carcinoma was induced subcutaneously in nude mice (n = 18), using four different cell lines. Ultrasound examination of the tumours was performed after 98 and 112 days, respectively, Central necrosis, rupture of th…