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At least 1,081 records · Page 60Linked to original sources

PubMed1978

Relation between 22-kHz ultrasonic signals and sociosexual behavior in rats.

The copulatory performance of male rats, tested in a large seminaturalistic environment, was assessed to determine the relation between 22-kHz ultrasonic vocalizations and a range of sociosexual behaviors. The male rats were tested until sexual exhaustion. Such ultrasonic signals were shown to occur in a wider range of sociosexual circumstances than previously reported; for example, the calls occcurred in particular social circumstances during the preejaculatory period as well as during the postejaculatory interval. There was no consistent evidence that the emission of this call during the postejaculatory period consistently functions to keep the female away from the male. The nature and occurrence of postejaculatory ultrasonic signals showed increasing variability in successive ejaculatory series. The results of this and previous studies are interpreted within a semiotic theory of communication. The 22-kHz call is described as a message that makes available the information that the sender is in a socially depressed and withdrawn state.

Aggression↗

PubMed1998

Clarification of small volume microbial suspensions in an ultrasonic standing wave.

The removal of Saccharomyces cerevisiae and Escherichia coli from 2.5 ml suspensions in ultrasonic standing wave formed at 1 or 3 MHz has been characterized. The standing wave was set up by a plane transducer and reflector mounted in the vertical plane. Cells in the ultrasonic field first concentrated in vertical planes at half wavelength separations. The ultrasound was then pulsed to allow clumps of concentrated cells to sediment in a controlled way during the short 'off' intervals. Yeast removal from suspension at a concentration of 3 x 10(9) ml-1 (14% volume v/v) was 99.5% in a total time of 4.5 min. Almost total (99.5%) clarification of prokaryote (E. coli) suspension was achieved here for the first time in a standing wave field. The clarification of a 1.3 x 10(11) ml-1 (16% v/v) E. coli suspension occurred over 11.5 min. The period decreased to 7 min in the presence of a polycationic flocculant, polyethyleneimine. The implications of the results for design of systems to further reduce clarification times are discussed. Removal efficiency for both S. cerevisiae and E. coli decreased with decrease in cell concentration. This concentration dependence is shown not to be simply a consequence of acoustic interaction between single cells. Flow cytometry of stained cells detected no loss of cell viability arising from the ultrasonic procedure.

Bacteriological Techniques↗

PubMed1975

[The diagnosis of gall-stones by ultrasonics (author's transl)].

Ultrasonic and radiological tests were compared in 267 patients suspected of having gall-stones. Radiological diagnosis was not possible in 20, because of lack of opacification, while in nine a gall-bladder was not demonstrable by ultrasound. In 226 the two tests coincided (positively or negatively), with 21 negative cholecystograms being interpreted as proof of stone. Seven of twelve discordant results were proven at operation: in three the ultrasonic, in four the radiological diagnosis was confirmed. Because of its accuracy, simplicity and absence of any risk ultrasonics is recommended as the first test to be performed if cholelithiasis is suspected.

Cholecystography↗

PubMed2000

Ultrasonic contact microprobe: experimental results.

At the Department of Neurosurgery, School of Medicine, University of Zagreb, the original ultrasonic contact microprobe (UCM) was designed. The efficacy of the instrument was tested on 120 brains of Wistar strain rats. The authors have been investigating the possibility of transferring high-energy ultrasound through the titanium wire probe of the device and the efficacy of UCM in controlled punctiform destruction of brain tissue. Light and electron microscope assessed the lesions made in the brains of experimental rats. Histological findings in the preparations showed the zone of thermal injuries from 100 to 200 microm and the zone of ultrastructural changes from 200 to 300 microm, indicating the sparing effect of the microprobe with regard to the adjacent neurovascular structures. The small dimensions of the ultrasonic contact microprobe (1.6 mm) enable its introduction through the operating canal of a ventriculoscope. Further research is expected to show the efficacy of the ultrasonic contact microprobe in endoscopic neurosurgery.

Animals↗

PubMed2003

[Preliminary results for superficial parotidectomy using the ultrasonically activated scalpel (Ultracision Harmonic Scalpel)].

BACKGROUND: The high density of blood vessels in the parotid gland, the direct vicinity to the facial nerve and the narrow surgical situs require efficient intra- and postoperative hemostasis. The ultrasonic scalpel (US) accomplishes both tissue dissection and vessel coagulation simultaneously by an ultrasonically activated shear movement of 55 500 Hz. The combination of hemostasis and tissue dissection particularly qualifies US for use in surgery of the parotid gland. Until now, there have been no published studies about application of US in surgery of the parotid gland. METHOD: 20 patients with benign parotid tumors treated with a conventional technique of superficial parotidectomy and 20 patients with a superficial parotidectomy using the ultrasonically activated scalpel were examined in regard to intra- and postoperative hemostasis, wound healing and postoperative pain. Also, the quality of the histopathological specimen obtained by US was evaluated. RESULTS: In 85 % (17/20) of superficial parotidectomy efficient intraoperative hemostasis did not require electrocoagulation. In 15 % (3/20) of parotid tumors additional bipolar electrocoagulation were required because of venous bleeding from vessels exceeding 2.0 mm in diameter. Postoperative bleeding did not occur at all. Wound healing was uneventful in all cases. Surgery-related postoperative pain was not intensified. Time of operation was shortened. Histopathological evaluation, especially in the margin area, was not impaired. CONCLUSION: The US offers tissue dissection with effective intra- and postoperative hemostasis. The combination of simultaneous tissue dissection and hemostasis enables a good overall view and control of the surgical site. In addition, based on the mechanical function the US has only a minimal thermal effect on neighboring tissues and enables controlled tumor resection without damaging the facial nerve.

Adult↗

PubMed1992

Preliminary experience using an ultrasonic aspirator for laparoscopic cholecystectomy.

An ultrasonic aspirator (Olympus) specially designed for laparoscopic surgery, which also includes cautery and suction-irrigation systems, was evaluated in 40 patients undergoing laparoscopic cholecystectomy. The generating power of each system is controlled by hand or foot switches, and most operating procedures could easily be performed through a 10 mm trocar inserted through the abdominal wall. The ultrasonic aspirator successfully fragmented and aspirated soft tissue, allowing a precise differentiation between the cystic duct and artery, small vessels, lymphatics and fibrous tissue. Removal of the gallbladder could be performed successfully using the cautery and ultrasonic aspirator, whereby parts of cauterization or division could easily be identified. Identification of the cystic duct and artery, course of the cystic duct and Hartmann's pouch in the same field of vision was possible which is important for avoiding major complications such as injury of the common bile duct. No complications were seen during or after surgery in any of the patients.

Cholecystectomy, Laparoscopic↗

PubMed1981

[Ultrasonic modelling of bone cement - (reoperation of total hip endoprosthesis) (author's transl)].

In medicine ultrasound is very common in diagnostic and therapeutic applications, in surgery especially as so-called ultrasonic lithotripsy. Up to now experiences in bone surgery are not very successful. Bone cement (PMMA) is a thermoplastic material. Therefore results of ultrasonic lithotripsy cannot be simply transmitted. Investigations show that, because of their thermoplastic quality, the ultrasonic method may be helpful in modelling bone cement, for example in changing endoprosthesis. The preconditions for the use of high frequent oscillating probes are examined experimentally. The necessary visual distinction of bone cement and natural bone may be intensified by fluorochrome labelling of cement.

Bone Cements↗

PubMed1999

Experience with an ultrasonic aspirator in neuroendoscopy.

This report describes the clinical application of an ultrasonic aspirator for endoscopic neurosurgery. Eight patients with intraventricular hematoma with complete tamponade of the ventricular system and marked hydrocephalus were treated with the ultrasonic aspirator for endoscopic neurosurgery. Clinical evaluation and neuroimaging studies were obtained for one month. Removal of hematoma was confirmed on follow-up imaging. The ultrasonic aspirator is operated by electrostriction transducer on low generating power (15-30 watts). Its tube has an outer diameter of 1.8 mm. This aspirator is designed to fragment and aspirate the cattle-liver. On observing the adjacent neural and vascular structures with the neuroendoscope, the massive hematoma within the ventricles is removed with the use of this aspirator. Subtotal removal (> 90% of hematoma volume) was achieved in all patients. All patients tolerated the procedure well. However, postoperative re-rupture occurred in two patients prior to aneurysm clipping following an immediate interval. Three patients with hypertension, two patients with head trauma, and one patient after aneurysm clipping were discharged home within one month after treatment. Preliminary experience with this aspirator has demonstrated its feasibility and safety. Clinical application of this technique is expected in other fields of neurosurgery.

Adult↗

PubMed1983

Ultrasonic absorption evidence for structural fluctuations in frog virus 3 and its subparticles.

The structural fluctuations specific to self-assemblies of biological molecules have been investigated further with ultrasonic techniques by using frog virus 3 (FV3). We compared the ultrasonic properties of complete FV3 virions and of several subparticles that may be obtained from this DNA virus: (i) the central nucleoprotein core versus its component DNA and proteins in a dissociated state; (ii) the core versus the capsidless subparticle, consisting of the core surrounded by the lipid membrane; and (iii) the complete virus versus the capsidless subparticle. The ultrasonic absorption by the core particle was quite large compared with the absorption by other nucleoprotein assemblies, suggesting that the core contains some organized structure. Both the core and the complete virus absorbed ultrasound more than did the capsidless subparticle. The difference spectrum for the virion relative to the capsidless subparticle may represent a single relaxation and is analyzed, by using a recent model, in terms of volume fluctuations due to radial movements in the virion. These fluctuations are much smaller than can be detected in virus crystals with present-day x-ray techniques.

Animals↗

PubMed2000

Ultrasonic surgical system (SONOPET) for microsurgical removal of brain tumors.

We use the ultrasonic surgical system in the treatment of brain tumors such as meningioma, neurinoma, glioma, etc. SONOPET is a useful and safe ultrasonic surgical system for microsurgery. The outer diameter of the tip of ultrasonic surgical systems is usually 2.5 mm and the inner diameter 2.0 mm. However, the outer diameter of the SONOPET is 1.9 mm and the inner diameter 1.5 mm. Even in a deep site, because of the small diameter tip, the operation can be done easily. Further, the very thin outer diameter of the tip flue, 5 mm, makes it easy to operate in the deep site. The maximum amplitude of the distal end tip, which can be an important factor in tissue fragmentation, is 240 microns. It is said that the thinner tip breaks down easily, but by reducing metal fatigue the lifetime of the tip is longer and a larger amplitude can be obtained. As a result, hard tissue fragmentation becomes available even with a thinner tip. The handpiece is very light in weight, approximately 110 g, helping to reduce operator fatigue when in long term use. The weight is approximately one-half of conventional types. Because of the high efficiency of the electricity/vibration energy conversion rate, the handpiece does not heat up during the operation. Also, since water cooling is not necessary, the procedures before and after use are simple. Changing the handpiece during the operation is also easy.

Brain Neoplasms↗

PubMedDate not supplied

Effect of ultrasonication on the stability of oligonucleotides adsorbed on nanoparticles and liposomes.

In the present study, oligonucleotides were adsorbed onto the surface of cationic liposomes and nanoparticles at different ratios. As a result, the surface charges of the colloidal carriers were decreased with increasing oligonucleotide concentration. At a certain oligonucleotide concentration, complete charge neutralization led to the aggregation of the carrier systems. Further increasing oligonucleotide concentrations reversed the surface charge of liposomes and nanoparticles to a negative one. Ultrasonication was investigated as a possible means for the homogenization of the formed aggregates. However, the use of ultrasonication led to a time-dependent damage of oligonucleotides adsorbed onto AH-Chol liposomes and MMAEMC-nanoparticles, as well as of unbound oligonucleotides. Nearly 60% of the oligonucleotides adsorbed to MMAEMC-nanoparticles and 65% of ODNs adsorbed to the liposomes were degraded by the effect of cavitation produced by ultrasonication within 10 min. In contrast, the oligonucleotides were protected from degradation when DEAE-stabilized PHCA-nanoparticles were employed as ODN carriers. More than 80% of the oligonucleotides entangled in the surface matrix of these nanoparticles remained intact.

Cyanoacrylates↗

PubMed1980

On the problem of milling and ultrasonic treatment of asbestos and glass fibers in biological and analytical applications.

In preparing fiber suspensions for biological applications, as well as in many analytical procedures, the fibers--e.g. asbestos and glass--often have to be mechanically diminished and ultrasonically treated. Such treatments may sometimes produce changes in the physical and chemical properties of the original fiber samples. Measurements have been made to estimate the changes in fiber shape, size, and structure after milling and ultrasonic treatment. The results have shown that milling procedures not only change the size distribution, but also the particle shape and crystal structure of asbestos fibers. Ultrasonic energy (50 kHz) had practically no influence on the crystal structure, but in long-term applications it produces changes in fiber size and fiber concentration.

Asbestos↗

PubMed1998

Ultrasonic extraction and field-portable anodic stripping voltammetry for the determination of lead in workplace air samples.

An on-site, field-portable analytical method for the determination of lead in workplace air samples, based on the use of ultrasonic extraction and anodic stripping voltammetry (ASV), was evaluated. Workplace air samples were obtained using a standard method involving particulate collection onto mixed cellulose ester membrane filters. Samples were collected at work sites where airborne particulates were generated from the abrasive blasting of lead-containing paint on highway bridges. Ultrasonic extraction (UE) of air filter samples in diluted nitric acid, followed by portable ASV, was used for the determination of lead. Also, performance evaluation samples consisting of reference materials of known lead concentration were subjected to the UE-ASV procedure for lead determination. Confirmatory analyses of the air filters and performance evaluation samples subjected to the UE-ASV lead measurement method were conducted by hotplate digestion in concentrated nitric acid and 30% hydrogen peroxide, followed by inductively coupled plasma-atomic emission spectrometric (ICP-AES) determination of lead. Recoveries of lead from performance evaluation materials (when using the UE-ASV method) were found to be quantitative. The performance of the UE-ASV method for lead in air filters was found to be acceptable, as evaluated by comparison with results from hotplate strong acid digestion followed by ICP-AES analysis. Based on the results of this study, the ultrasonic extraction/portable ASV procedure demonstrates potential for the on-site determination of lead in personal breathing zone and area air samples.

Air Pollutants, Occupational↗

PubMed2005

Gas chromatography-mass spectroscopy analysis of emissions from cement when using ultrasonically driven tools.

BACKGROUND: Ultrasonically driven tools have been used to reduce the incidence of complications during cement removal at revision hip replacement operations. These have been shown to be safe and effective in various ways, but produce fumes. METHODS: Using gas chromatography-mass spectroscopy, we analyzed the fumes produced during the use of these ultrasonic tools for the removal of bone cement, both in the laboratory and during actual surgery. RESULTS: Benzene, styrene, methylmethacrylate, xylene, toluene, isopropyl alcohol and dichlorobenzene were some of the substances isolated from the fumes in the laboratory. Styrene and methylmethacrylate were the main components. Concentrations of all the above components taken from the breathing zone of the operating staff during actual surgery were well below the safety limits. INTERPRETATION: The use of ultrasonic tools for cement removal appears to be safe.

Air Pollutants, Occupational↗

PubMed2002

The effect of ultrasonic vibration on the compaction characteristics of ibuprofen.

An ultrasonic (US) compaction rig has been developed, capable of providing compaction pressure together with high-power ultrasonic vibrations of 20 kHz to a powder or granular material in a die. The rig has been used to investigate the effect of ultrasound on the compaction properties of ibuprofen, a drug with poor compaction properties which produces tablets that are weak and frequently exhibit capping. It was found that coherent ibuprofen tablets could be prepared by ultrasound-assisted compaction at pressures as low as 20-30 MPa. Application of ultrasound before and after compaction was found not to be as effective as ultrasound applied during compaction. The breaking forces of the tablets produced with ultrasound applied during compaction were found to be consistently significantly higher than when compaction was performed conventionally, or with ultrasound applied before or after compaction. Application of ultrasound during compaction made it possible to increase tablet mechanical strength, typically by a factor of 2-5. It was concluded that pressure should be applied together with ultrasound in order to achieve a better acoustical contact, which is required to transmit vibrations from the horn to the material, and also to bond the surfaces of the particles. Ultrasound application during ibuprofen compaction also resulted in an increase in the apparent density, in relation to the apparent density of conventionally prepared tablets, of up to 14.4%. Ultrasound appears to improve particle rearrangement and provides energy for partial melting of particle asperities and subsequent fusion of particle surfaces, so as to increase interparticulate bonding. Solid bridge formation was thought to result in a reduction of void space, which in turn reduced the rate of water penetration into the compacts and consequently increased disintegration and dissolution times. It was found that the results of ultrasound-assisted compaction are influenced by formulation and US time. When ibuprofen was mixed with a second material, such as dibasic calcium phosphate dihydrate (DCP) or microcrystalline cellulose (MCC), stronger tablets were prepared by ultrasound-assisted compaction compared to the compacts containing no filler. Positive interactions were considered to have occurred due to ultrasound-induced bonding between the two materials. With an increase in DCP and MCC concentration in ibuprofen formulations, disintegration and drug dissolution rates of the tablets produced with ultrasound significantly increased. Using temperature-sensitive labels it was found that thermal changes occurred in powdered solids undergoing ultrasound-assisted compaction. Increases in the temperature of tablets were related to US amplitude and US time. With an increase in US amplitude from 5 to 13 microns, the temperature of the DCP tablet surface increased from 40 to 99 degrees C. With an increase in US time from 1 to 5 sec, the temperature of the surface of ibuprofen tablets increased from 43 to 60 degrees C. Increased tablet temperature was thought to be due to ultrasonic energy dissipation turned into heat. X-ray powder diffraction (XRD) studies of ibuprofen tablets prepared by ultrasound-assisted compaction at 32 MPa revealed that no changes in chemical or/and crystalline structure of the material occurred when ultrasound was applied for up to 5 sec (US amplitude 7 microns). An XRD study of DCP tablets produced by ultrasound-assisted compaction at 32 MPa with ultrasound of different amplitudes (5, 7, 13 microns) applied for 2 sec indicated that no material deterioration occurred in all the tested samples.

Compressive Strength↗

PubMed1978

Effect of ultrasonic irradiation on mammalian cells and chromosomes in vitro.

Human peripheral blood and HeLa cells were irradiated in vitro at the ultrasonic frequency of 65 kHz. The whole blood and HeLa cell suspensions were exposed to continuous and pulsed ultrasonic power levels of 0.12, 0.16, 0.72, 1.12 and 2.24 W for a period of one minute. The method of ultrasonic irradiation was carried out with the whole blood or HeLa cell suspensions coupled directly to a cylindrical transducer while heating of the cell suspensions in excess of 41 degrees c was avoided. Irradiated and unirradiated peripheral blood lymphocyte chromosome cultures were prepared and scored for selected numerical and morphological abberrations. There was no significant difference in the frequency of chromosomal aberrations between irradiated and unirradiated cells. The fraction of cells S surviving after an exposure to an ultrasound dose of D can be represented by S = exp (-D/Do). Further, Do is shown to depend on the time after exposure at which survival is assayed.

Cell Survival↗

PubMed2003

Measurement of ultrasonic attenuation coefficient in polymer gel dosimeters.

A technique is described for investigation of the ultrasonic attenuation coefficient for evaluation of absorbed dose in polymer gel dosimeters. Using this technique the attenuation coefficient as a function of absorbed dose in PAG and MAGIC polymer gel dosimeters was measured. The ultrasonic attenuation coefficient dose sensitivity for PAG was found to be 2.9 +/- 0.3 dB m(-1) Gy(-1) and for MAGIC gel 4.2 +/- 0.3 dB m(-1) Gy(-1). Unlike previous studies of ultrasonic attenuation in polymer gel dosimeters this technique enables a direct measure of the attenuation coefficient.

Densitometry↗

PubMed2004

Ultrasonic device for the noninvasive diagnosis of compartment syndrome.

An ultrasonic device for the diagnosis of acute compartment syndrome is described and results on six human cadaveric legs are presented. The ultrasonic device uses a pulsed phase locked loop (PPLL) to measure sub-micrometer displacements of the fascia wall. These displacements occur as a result of volume expansion of the muscle compartment of the lower leg and are related to changes in intramuscular pressure (IMP). In the cadaveric tests, the PPLL detected changes in compartment diameter resulting from IMP changes of 1 mmHg and from infusions of 0.25 ml saline increments. Based on these results, the ultrasonic PPLL appears to have the potential to become a low-cost, portable and noninvasive alternative to current methods for diagnosing acute compartment syndrome.

Acute Disease↗