Search results for "Ultrasonic sensor"
showing 9 items of 139 documents
Tailoring the excitation of fundamental flexural guide waves in coated bone by phase-delayed array: Two-dimensional simulations
2015
The fundamental flexural guided wave (FFGW) enables ultrasonic assessment of cortical bone thickness. In vivo, it is challenging to detect this mode, as its power ratio with respect to disturbing ultrasound is reduced by soft tissue covering the bone. A phase-delayed ultrasound source is proposed to tailor the FFGW excitation in order to improve its power ratio. This situation is analyzed by 2D finite-element simulations. The soft tissue coating (7-mm thick) was simulated as a fluid covering an elastic plate (bone, 2–6 mm thick). A six-element array of emitters on top of the coating was excited by 50-kHz tone bursts so that each emitter was appropriately delayed from the previous one. Respo…
Endoluminal ultrasonic examination of sessile polyps and early carcinomas of the rectum
1989
The results of conventional endosonographic techniques in the assessment of early carcinomas and sessile polyps of the rectum have been unsatisfactory. We therefore developed a new technique in which the rectal cavity is filled directly with water. Using this technique, the anatomy of small rectal tumors is preserved and the layers of the rectal wall are easier to differentiate, especially with a 10-MHz scanner. The clinical results in 66 patients demonstrate that this new technique is very accurate in the preoperative staging of adenomas and T1-carcinomas of the rectum.
Effects of ultrasonically activated irrigants with or without surfactant on smear layer removal after post space preparation
2012
The aim of this study was to compare the effects of different NaOCl and EDTA formulations with/without ultrasonic use on smear layer removal and root canal surface characteristics after post space preparation. Study design: After post space preparations, forty-six teeth were subjected to different post space irrigation regimes; G1, 17% EDTA; G2, 17% EDTA+Ultrasonic activation; G3, EDTA-T; G4, EDTA-T+Ultrasonic activation; G5, NaOCl; G6, NaOCl+Ultrasonic activation. Specimens were examined under scanning electron microscope and scored for debris and smear layer removal and dentinal tubule opening and statistically analyzed with Kruskal Wallis and Dunn's test. Significance value was set at p<…
Variations in acoustical beam properties of intracoronary Doppler catheters.
1993
The limitations of coronary angiography in assessing the functional significance of coronary obstructions is well known. While the critical variable of coronary blood flow cannot be readily measured, intraluminal Doppler sonography offers useful related functional information on blood flow velocity. In order to fully evaluate Doppler signals it is essential to have exact knowledge of the transducer transmission characteristics and of the ultrasound beam topology. In an experimental set-up, the transmitter-receiver characteristics of five commonly used Doppler catheters were investigated. In comparing the beam characteristics we found inhomogeneities in the lateral beam spread. At a penetrat…
<title>Ultrasound detection of cavitation as a phenomenon common to intervention devices causing tissue ablation</title>
1992
Cavitation previously has been observed in association with ultrasonic angioplasty and high- frequency rotational atherectomy. This study evaluates the production of cavitation accompanying the use of several catheter-based devices under development or in current use in the practice of interventional cardiology. Catheters were examined in an in vitro model, and cavitation was evaluated using standard ultrasound imaging equipment. Cavitation was detected with each of the devices that effects tissue ablation, but not tissue resection. Devices produced characteristic patterns of cavitation dependent on the mode of energy release of the device. The size, but not the intensity, of the cavitation…
The anatomy of the heart in the sonogram. A comparison between anatomic and ultrasonic cross-section.
1977
Cardiac sonography has only recently been introduced as a diagnostic procedure. In order to facilitate the interpretation and evaluation of the ultrasonic cardiac cross-section displayed by this two-dimensional technique, we performed anatomic cross-sections corresponding to ultrasonic cross-sections. The ultrasonic cross-sectional images were taken from children with a real-time-motion scanner. The anatomic cross-sections were taken from adult hearts. Two ultrasonic transverse cross-sections are compared with the two corresponding anatomic cross-sections and three ultrasonic longitudinal cross-sections with one corresponding anatomic cross-section. The direct comparison between anatomic an…
Review of ultrasonic irrigation in endodontics: increasing action of irrigating solutions
2011
Introduction: Effective irrigant delivery and agitation are prerequisites for successful endodontic treatment. Ultrasonic irrigation can be performed with or without simultaneous ultrasonic instrumentation. Existing literature reveals that ultrasonic irrigation may have a very positive effect on chemical, biological and physical debridement of the root canal system as investigated in many in vitro studies. Objective: The purpose of this review article was to summarize and discuss the available information concerning ultrasonic irrigation in endodontics. Methods: This article presents an overview of ultrasonic irrigation methods and their debridement efficacy. In this paper the relevant lite…
Assessment of the tibia using ultrasonic guided waves in pubertal girls
2002
The purpose of this study was to compare low frequency ultrasonic guided wave measurements with established ultrasound and bone density measurements in terms of their ability to characterize the tibia in pubertal girls. Subjects were 12-14-year-old girls ( n=106) who were participating in a calcium and vitamin D intervention study. A prototype low frequency pulse transmission device consisting of a uniaxial scanning mechanism and low frequency transducers orientated perpendicularly to the limb was used to measure two ultrasound velocities in the tibia. The first velocity, V1, was that of the first arriving signal, similar to that measured by existing commercial tibial ultrasound devices. Th…
Advances in Nanoliposomes Production for Ferrous Sulfate Delivery
2020
In this study, a continuous bench scale apparatus based on microfluidic fluid dynamic principles was used in the production of ferrous sulfate-nanoliposomes for pharmaceutical/nutraceutical applications, optimizing their formulation with respect to the products already present on the market. After an evaluation of its fluid dynamic nature, the simil-microfluidic (SMF) apparatus was first used to study the effects of the adopted process parameters on vesicles dimensional features by using ultrasonic energy to enhance liposomes homogenization. Subsequently, iron-nanoliposomes were produced at different weight ratios of ferrous sulfate to the total formulation components (0.06, 0.035, 0.02, an…