Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ULTRASONICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2000

Position paper: sonic and ultrasonic scalers in periodontics. Research, Science and Therapy Committee of the American Academy of Periodontology.

Ultrasonic and sonic scalers appear to attain similar results as hand instruments for removing plaque, calculus, and endotoxin. Ultrasonic scalers used at medium power seem to produce less root surface damage than hand or sonic scalers. Due to instrument width, furcations may be more accessible using ultrasonic or sonic scalers than manual scalers. It is not clear whether root surface roughness is more or less pronounced following power-driven scalers or manual scalers. It is also unclear if root surface roughness affects long-term wound healing. Periodontal scaling and root planing includes thorough calculus removal, but complete cementum removal should not be a goal of periodontal therapy. Studies have established that endotoxin is weakly adsorbed to the root surface, and can be easily removed with light, overlapping strokes with an ultrasonic scaler. A significant disadvantage of power-driven scalers is the production of contaminated aerosols. Because ultrasonics and sonics produce aerosols, additional care is required to achieve and maintain good infection control when incorporating these instrumentation techniques into dental practice. Preliminary evidence suggests that the addition of certain antimicrobials to the lavage during ultrasonic instrumentation may be of minimal clinical benefit. However, more randomized controlled clinical trials need to be conducted over longer periods of time to better understand the long-term benefits of ultrasonic and sonic debridement.

Aerosols↗
PubMed2002

Accessibility of an ultrasonic furcation tip to furcation areas of mandibular first and second molars.

The purpose of this study was to compare an ultrasonic furcation tip with an ultrasonic conventional tip and a hand scaler on accessibility to furcation areas of mandibular first and second molars. The study was conducted on 360 artificial molars that were replicated from 30 mandibular first molars and 30 second molars with silicone impression material and resin. The furcation areas of each molar were coated with red nail colour for artificial calculus. The root areas from the cement-enamel junction apically were covered with silicone rubber simulating gingival tissue. Then the models were instrumented on the buccal or lingual aspects by an experienced operator with each of the following instruments: an ultrasonic furcation tip, an ultrasonic conventional tip and a hand scaler. After instrumentation the percentage of the furcation area with residual artificial calculus was assessed using a computerised imaging system. Results showed that when the horizontal pocket depth was less than 2mm, all three instruments showed good accessibility. When the horizontal pocket depth was more than 2mm, the ultrasonic conventional tip and the hand scaler showed less removal of artificial calculus than the ultrasonic furcation tip (P < 0.01). Efficiency of the ultrasonic furcation tip was fairly satisfactory for the horizontal pocket up to the ridge of the furcation roof.

Dental Calculus↗
PubMed2005

Effects of ultrasonic scaling and hand-activated scaling on tactile sensitivity in dental hygiene students.

PURPOSE: This study was conducted to determine if tactile sensitivity varies in dental hygiene students who use the ultrasonic scaler, as compared to those who scale with hand-activated instruments. METHODS: A two-group, randomized subjects, pretest-posttest design was carried out mid-semester for five weeks on 40 first-year dental hygiene students who met the inclusion criteria of this study and who agreed to participate. A convenience sample of 40 consenting, first-year dental hygiene students were randomly assigned to one of two groups (experimental or control). After establishing a baseline tactile sensitivity score with the Vibratory Sensory Analyzer (VSA), experimental group subjects used the ultrasonic scaler to remove 4 cc's of artificial calculus from a typodont in a controlled, simulated clinical setting for 45 minutes, while each control subject manually scaled 4 cc's of artificial calculus on a typodont in a controlled, simulated situation for 45 minutes. Immediately following exposure to either the ultrasonic scaler or hand-activated scaling instruments, tactile sensitivity scores were obtained using the VSA. Analysis of variance with one repeated measures factor was used to determine between group and within group differences on the pretest and posttest tactile sensitivity scores. RESULTS: Results revealed that tactile sensitivity increased after a 45-minute scaling session with the ultrasonic scaler. Pretest to posttest changes in tactile sensitivity for the ultrasonic scaling group exhibited a much larger threshold as compared to those in the hand-activated scaling group, supporting a gain in students' level of sensitivity with stimulus (vibration). Tactile sensitivity decreased in those who used hand-activated scaling instruments. The thumb, index, and middle fingers of students in both groups showed similarities in tactile sensitivity, with the index finger being the most sensitive. CONCLUSION: Tactile sensitivity decreases with hand-activated scaling and increases with ultrasonic scaling over a 45-minute period. Short-term vibration exposure from the ultrasonic scaler is insufficient to negatively affect tactile sensitivity.

Analysis of Variance↗
PubMed2007

Types and functions of ultrasonic vocalizations in laboratory rats and mice.

Many laboratory rodents emit ultrasonic vocalizations. The purpose of this review is to highlight the types and functions of ultrasonic vocalizations emitted by laboratory rats and mice. Rats emit 3 types of ultrasonic vocalizations, depending on the animal's age, its environmental conditions, and its affective state. Rat pups emit a 40-kHz vocalization when they are separated from their mothers. Adult rats emit a 22-kHz vocalization in anticipation of inescapable aversive stimuli. These two types of vocalizations reflect a negative affective state of the animal. Rats produce a 50-kHz vocalization under nonaversive conditions, and these vocalizations reflect a positive affective state of the animal. Adult mice produce several different types of ultrasonic calls that can be classified as different syllables. Mice produce ultrasonic vocalizations during nonaggressive interactions, particularly during mating behaviors, but these vocalizations are not indicators of negative or positive affect. Therefore, the function of ultrasonic vocalizations in adult mice is likely only to facilitate or inhibit social interactions. Understanding the types and functions of ultrasonic vocalizations emitted by laboratory rodents may enable researchers and animal care personnel to use vocalizations as an indicator of an animal's behavior and affect.

Age Factors↗
PubMed1997

Comparison of jet and ultrasonic nebulizer pulmonary aerosol deposition during mechanical ventilation.

Increased delivery of aerosol to a model lung (attached to a mechanical ventilator) has been demonstrated with an ultrasonic nebulizer as compared to a jet nebulizer. This study examined whether the increased aerosol deposition with an ultrasonic nebulizer could also be demonstrated in vivo. Seven patients (6 male and 1 female) were studied during mechanical ventilalion (Siemens Servo 900C, Middlesex, UK) after open heart surgery. Two studies were performed in each patient. In the first study, aerosol was delivered via a Siemens Servo 945 nebulizer system (high setting) driving a System 22 Acorn jet nebulizer (Medic-Aid, Sussex, UK) containing 3 mL (99m)technetium-labelled human serum albumin (99mTc-HSA) (50 microg; activity 74 MBq). In the second study, a DP100 ultrasonic nebulizer (DP Medical, Meylan, France) containing 12 mL 99mTc-HSA (50 microg; activity 185 MBq) was used. Pulmonary deposition was quantified using a gamma camera. The humidification of the circuit and the ventilator settings were kept constant according to the patient's clinical requirements. The total lung aerosol deposition (mean+/-SD), as a percentage of initial nebulizer activity, was greater using the ultrasonic nebulizer than using the jet nebulizer (53+/-1.4 vs 2.3+/-0.9%; p<0.002). The ultrasonic nebulizer was also associated with a reduction in the time required to complete nebulization (9 vs 21 min, respectively) (p<0.0001). Use of the DP100 ultrasonic nebulizer more than doubled lung deposition compared with the System 22 jet nebulizers in mechanically-ventilated patients. Their efficiency, speed of drug delivery, and compatibility with mechanical ventilator circuits make ultrasonic nebulizers potentially attractive for use during mechanical ventilation.

Administration, Inhalation↗
PubMed1996

Clinical use of an aerosol-reduction device with an ultrasonic scaler.

The traditional use of ultrasonic scalers has been to remove heavy deposits of calculus. Today, there is an increasing use of ultrasonic scalers in all areas of periodontal treatment, including periodontal maintenance and root planing. Coolant liquid must be used with an ultrasonic scaler because of heat buildup in the ultrasonic handpiece and scaler tip. The coolant liquid causes an infection control problem because of contaminated aerosols and a patient management problem because of water buildup in the patient's mouth. Data demonstrating the presence of blood in ultrasonic aerosols are presented. The clinical use of an aerosol reduction device that fits on an ultrasonic scaler is detailed. This device reduces the aerosol produced by more than 93%. Research that shows a reduction in water buildup in the patient's mouth of more than 76% (P < .01) is presented. The aerosol reduction device appears to greatly reduce many of the problems associated with the coolant liquid used during ultrasonic scaling.

Aerosols↗
PubMed1997

Incorporation of ultrasonic imaging in an optically coupled frameless stereotactic system.

Frameless stereotactic interactive tracking systems relate a point in the surgical field to a corresponding point on the patients MR or CT scans in multiple planes. A basic weakness with these systems is that they cannot compensate for movement of target points due to brain shift caused by CSF drainage or lesion removal. Real time images can be obtained using ultrasonic techniques but the poor quality and definition and the ill-defined scan plane make interpretation difficult and reduce the usefulness of this modality. The authors have combined these two modalities by mounting light emitting diodes (LEDs) on the ultrasonic probe, thus allowing a "virtual tip" to be developed in the centre of the ultrasonic beam, and tracked via an optically coupled frameless stereotactic system (Radionics, OTS). This has allowed a direct correlation between pre-operative MR and the per-operative ultrasonic images using reformatted MR images. Ultrasound images are obtained through a separate skull opening and the image plane is determined by the position of the virtual tip. The ultrasonic and MR images are presented side by side for visual comparison. Minimally invasive tumour resection or haematoma removal could be carried out under ultrasonic guidance with direct interactive relation to the preoperative MR scans. Alternatively interactive image directed surgical procedures can be up-dated in real time by dynamic ultrasonic images taken in clearly defined scan planes.

Brain Mapping↗
PubMed1977

The anatomy of the heart in the sonogram. A comparison between anatomic and ultrasonic cross-section.

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 and ultrasonic cross-sections best promotes the understanding of the latter: such a comparison shows certain gaps of information in the ultrasonic display, mostly due to the physical prerequisites of the technique. Morphological details, therefore, should be interpreted with great care. In spite of these disadvantages, sonography is the only non-invasive method that provides an exact analysis of the heart's structure. In addition to this, the real-time-motion technique allows observation of the movements of cardiac structures.

Child↗
PubMed1996

Cannabinoid modulation of rat pup ultrasonic vocalizations.

The present study investigated the effects of the cannabinoid receptor agonist CP 55,940 (1-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl) phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol) and the cannabinoid receptor antagonist SR 141716A (N-(piperidin-l-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-me thyl-1 H-pyrazole-3-carboxamide hydrochloride) on ultrasonic vocalizations, body temperature and activity in 11-13-day-old rat pups. Testing occurred in a 5-min session 30 min following drug administration. CP 55,940 produced a dose-dependent decrease in ultrasonic vocalizations, with a 1000-micrograms/kg dose causing an almost complete inhibition of calls. Doses of 100 and 1000 micrograms/kg of CP 55,940, but not 10 micrograms/kg, caused significant hypothermia in the pups and the 1000 micrograms/kg dose also inhibited activity. The cannabinoid receptor antagonist SR 141716A (20 mg/kg) reversed the effects of 1000 micrograms/kg CP 55,940 on ultrasonic vocalizations and body temperature, but the benzodiazepine receptor antagonist flumazenil (20 mg/kg), the dopamine D1 receptor antagonist SCH 23390 (0.5 mg/kg) and the opioid receptor antagonist naloxone (1 mg/kg) did not. When administered alone, SR 141716A (20 mg/kg) increased pup ultrasonic vocalizations without affecting body temperature or activity. These results indicate that cannabinoids modulate ultrasonic vocalization production in rat pups in a manner that is independent of hypothermia. The increase in ultrasonic vocalizations produced by SR 141716A is one of the first reported behavioural effects of this drug and suggests that the endogenous cannabinoid ligand anandamide may be involved in the regulation of ultrasonic vocalizations.

Analysis of Variance↗
PubMed2004

Effects of ultrasonic energy on the wash fastness of reactive dyes.

The field of ultrasonic is still making strides towards perfection, but already many applications of ultrasonic energy have been found in science and technology. There is also a field called sonochemistry where ultrasonic energy is used to create some chemical and mechanical effects on matter immersed or solved in liquids. It was presumed that ultrasonic textile washing could be a competitive alternative to conventional textile washing techniques; and as such the following experiments were conducted. In this study, the effects of ultrasonic energy on the wash fastness of reactive dyes, which have three different reactive groups, were investigated. After dyeing with the conventional method, the samples were applied with three types of washing processes simultaneously (conventional, ultrasonic probe and ultrasonic bath) and comparisons were made. Three different fixing agents were used in the washing processes. Colourfastness, staining fastness, magnitude of total colour difference (DeltaE) and lightness difference of the colour (DeltaL) values of dyed samples were measured.

Journal Article↗
PubMed2005

Load characteristics of high power sandwich piezoelectric ultrasonic transducers.

Based on the equivalent circuit theory, the load characteristics of high power piezoelectric ultrasonic sandwich transducers are studied. Two types of loads are studied. One is liquid load as in ultrasonic cleaning, and the other is solid load as in ultrasonic drilling and machining. The effect of load and structure of the transducer on the resonance frequency of the transducer is analyzed. It is shown that the effect of load on the resonance frequency of sandwich transducers with different structures is different. For liquid load as in ultrasonic cleaning, the effect of the load on the resonance frequency of the sandwich transducer with symmetrical structure is the largest. It is the smallest for the transducer with its displacement node in the back metal cylinder. For solid load as in ultrasonic drilling and machining, the effect of the load on the resonance frequency of the sandwich transducer with its displacement node in the front metal cylinder is the largest. It is also the smallest for the transducer with its displacement node in the back metal cylinder. On the other hand, for some applications, such as ultrasonic drilling, when the lateral dimension of the tool is much less than that of the transducer, its effect on the resonance frequency of the transducer is small. The conclusions are useful in designing vibrating systems for different ultrasonic applications.

Journal Article↗
PubMed2006

A traveling wave ultrasonic motor of high torque.

A traveling wave ultrasonic motor of high torque with a new configuration is proposed in this paper. In the new design, a part of the motor serves as the stator. The rotor is the vibrator consisting of a toothed metal ring with piezoelectric ceramic bonded, which generates ultrasonic vibration. The rotor is in contact with the shell of motor and is driven by the friction between the rotor and the stator. This configuration not only removes the rotor in a conventional type of traveling wave ultrasonic motor but also changes the interaction between the rotor and the stator of the motor so that it improves the output performance of the motor. Although an electric brush is added to the ultrasonic motor, it is easy to be fabricated because of the low speed of motor. The finite element method was used to compute the vibration modes of an ultrasonic motor with a diameter of 100mm to optimize the design of the motor. A 9th mode was chosen as the operation mode with a resonance frequency about 25 kHz. According to the design, a prototype was fabricated. Its performance was measured. The rotation speed-torque curves for various frequencies were obtained. The result shows that its stall torque is greater than 4 Nm within a range of 400 Hz. This ultrasonic motor was used to drive the window glass of a mobile car and the result was satisfactory. In the further the research on the friction material between the stator and the rotor is under way to improve the efficiency of the ultrasonic motor.

Journal Article↗
PubMed2006

Ultrasonic drying of foodstuff in a fluidized bed: Parametric study.

The application of high power ultrasound for dehydration of porous materials may be very effective in processes in which heat-sensitive materials such as foodstuffs have to be treated. In fact, high-intensity ultrasonic vibrations are capable of increasing heat and mass transfer processes in materials. The application of ultrasonic energy can be made alone or in combination with other kind of energy such as hot-air. In this case, ultrasound helps in reducing temperature or treatment time. The aim of this work is to study the effect of air flow rate, ultrasonic power and mass loading on hot-air drying assisted by a new power ultrasonic system. The drying chamber is an aluminium vibrating cylinder, which is able to create a high intensity ultrasonic field in the gas medium. To that purpose the chamber is driven at its centre by a power ultrasonic vibrator at 21.8 kHz. Drying kinetics of carrot cubes and lemon peel cylinders were carried out at 40 degrees C for different air velocities, with and without ultrasound. The results show that the effect of ultrasound on drying rate is affected by air flow rate, ultrasonic power and mass loading. In fact, at high air velocities the acoustic field inside the chamber is disturbed and the effect of ultrasound on drying kinetics diminishes.

Computer Simulation↗
PubMed2006

Effect of sparse basis selection on ultrasonic signal representation.

Recently, adaptive sparse representations of ultrasonic signals have been utilized to improve the performance of scanning acoustic microscopy (SAM), a common nondestructive tool for failure analysis of microelectronic packages. The adaptive sparse representation of an ultrasonic signal is generated by decomposing it in a learned overcomplete dictionary using a sparse basis selection algorithm. Detection and location of ultrasonic echoes are then performed on the basis of the resulting redundant representation. This paper investigates the effect of sparse basis selection algorithms on ultrasonic signal representation. The overcomplete independent component analysis, focal underdetermined system solver (FOCUSS), and sparse Bayesian learning algorithms are examined. Numerical simulations are performed to quantitatively analyze the efficiency of ultrasonic signal representations. Experiments with ultrasonic A-scans acquired from flip-chip packages are also carried out in the study. The efficiency of ultrasonic signal representations are evaluated in terms of the different criteria that can be used to measure its performance for different SAM applications, such as waveform estimation, echo detection, echo location and C-scan imaging. The results show that the FOCUSS algorithm performs best overall.

Algorithms↗
PubMed2004

Precipitation of calcium carbonate by ultrasonic irradiation.

Supersaturated solution of calcium carbonate ([Ca2+] = 1.2 mmol/L, [HCO3-] = 3.2 mmol/L, pH = 8.8, T = 30 +/- 0.5 degrees C), a scale forming component, was irradiated by an ultrasonic homogenizer (24 kHz, 15-250 W/cm2) to study the factors that affect its precipitation rate. The factors of (1) depth of horn immersion, (2) ultrasonic intensity and horn tip size and (3) cavitation, which can affect the precipitation rate were investigated in this study. Ultrasonic irradiation was observed to accelerate the precipitation of calcium carbonate and it was found that there exists an optimum range of horn immersion depth for maximizing the precipitation rate. The experimental data also established that the precipitation rate was proportional to ultrasonic intensity and diameter of horn tip. These findings were correlated to the effects of physical mixing, that arises due to ultrasonic irradiation. However, the effect of cavitation in accelerating the precipitation rate was found to be small. Thus it is forwarded that the physical mixing effect, especially macrostreaming is the main factor that accelerates the precipitation rate of calcium carbonate during ultrasonic treatment. Further, neither the morphology nor the size of the calcium carbonate crystals formed were found to be affected by the ultrasonic irradiation.

Journal Article↗
PubMed2005

Enhancement of saccharin removal from aqueous solution by activated carbon adsorption with ultrasonic treatment.

This study investigates the use of ultrasonication as a pretreatment process and its effect on the adsorption characteristics of saccharin onto activated carbon (AC). Ultrasonic decomposition of saccharin was performed at a frequency of 500 kHz under argon and O2/N2 (20/80 vol%) atmospheres. Adsorption was carried out using a commercial activated carbon. The behavior of total organic carbon (TOC) during ultrasonication was investigated. Saccharin removal after 180 min of ultrasonication under Ar and O2/N2 atmospheres are 38% and 26%, respectively, while the amount of saccharin removed by activated carbon adsorption without US pretreatment is 40% after 16 h. After 16 h of AC adsorption with 180 min of ultrasonic pretreatment under Ar and O2/N2 atmospheres, both removal ratios increased to 75%. These results indicated that the pretreatment of sonication under O2/N2 leads to the increase in the amount of saccharin adsorbed on AC. On the other hand, the TOC removal by decomposition by ultrasound is not more than 5% in both Ar and O2/N2 atmospheres after 180 min ultrasonication. However, the TOC removal increased to 54% and 69% after 16 h of adsorption of saccharin pretreated by ultrasonication for 180 min under Ar and O2/N2 atmospheres, respectively. About 13% and 16% TOC removal in Ar and in O2/N2, respectively, were achieved due to adsorption of the by-products. It is considered that the improvement in TOC removal is also brought about by the formation of the by-products that were adsorbed onto AC.

Adsorption↗
PubMed2001

Ultrasonic vocalizations of preweanling rats: involvement of both alpha(2)-adrenoceptor and kappa-opioid receptor systems.

Stimulation of alpha(2)-adrenoceptors and kappa-opioid receptors increases the ultrasonic vocalizations of preweanling rats. The purpose of the present study was to determine whether alpha(2)-adrenoceptors and kappa-opioid receptors modulate ultrasonic vocalization production via a common mechanism. To that end, 11-day-old rats were injected with the alpha(2)-adrenoceptor antagonist yohimbine (0, 0.5, or 1.0 mg/kg, i.p.) or the kappa-opioid receptor antagonist nor-binaltorphimine (0, 5, or 10 mg/kg, i.p.). After 15 min, the same rats were injected with saline, the alpha(2)-adrenoceptor agonist clonidine (0.25 mg/kg, i.p.), or the kappa-opioid receptor agonist trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide methanesulfonate (U-50,488; 2.5 mg/kg, i.p.). Results showed that both clonidine and U-50,488 increased the ultrasonic vocalizations of preweanling rats. Not surprisingly, clonidine-induced ultrasonic vocalizations were blocked by yohimbine, while U-50,488-induced vocalizations were blocked by nor-binaltorphimine. Importantly, yohimbine also attenuated the vocalizations produced by U-50,488, whereas nor-binaltorphimine did not alter clonidine-induced ultrasonic vocalizations. Thus, it appears that alpha(2)-adrenoceptor and kappa-opioid receptor stimulation increases ultrasonic vocalization production via a common mechanism. It is likely that the kappa-opioid receptors responsible for modulating ultrasonic vocalizations are located "upstream" from the alpha(2)-adrenoceptors.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed2002

Ultrasonic measurement of gas flow using electrostatic transducers.

Ultrasonic gas flowmeters typically use narrowband piezoelectric transducer arrangements for interrogating the flow of gas in a pipe. In this work, the suitability of broadband electrostatic transducers operating at frequencies of up to 1 MHz for ultrasonic measurement of gas flow has been investigated. The transit time method of ultrasonic gas flow measurement was adopted and experiments were carried out using a laboratory test rig capable of producing a range of gas flowrates up to 17.5 m/s. The test rig also allowed easy interchange of different prototype flowmetering sections. Times of flight of ultrasonic waves interrogating the gas flow were measured using separate send/receive electrostatic transducer arrangements. Two flowmeter configurations were considered. The first interrogated the flow at 45 degrees in contra-propagating upstream and downstream directions. The second consisted of an up-stream interrogation at 45 degrees to the gas flow and an interrogation made normal to the flow direction. k factors correlating the fluid velocity along the ultrasonic path with the mean fluid velocity in the pipe were calculated using experimental ultrasonic data and anemometer measurements. All transducer configurations were numerically modelled using the computational fluid dynamics software package FLOTRAN (ANSYS Inc.). Theoretical gas flow velocities for both transducer arrangements were subsequently compared with experimental values and found to be in excellent agreement. A flow-dependent frequency shift of the received ultrasonic signals was also observed simultaneously with the transit time measurement.

Journal Article↗