PubMed · 4269941
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K Schmitz. 1973. [Extension vibrator].. https://pubmed.ncbi.nlm.nih.gov/4269941/
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The effect of hydrostatic pressure on the secondary structure of recombinant human interferon-gamma (rhIFN-gamma) and its biologically inactive truncated form rhIFN-Delta C15 has been studied using Fourier-transform IR (FTIR) spectroscopy. In situ observation of the pressure-induced changes using the diamond anvil cell shows that the alpha-helical structure is mainly transformed into disordered structure at high pressure. Increasing pressure also induces the formation of a gel. Addition of 0.5 M MgCl(2) significantly reduces the pressure stability. Releasing the pressure below 300 MPa results in the formation of intermolecular antiparallel beta-sheets, which is seldom observed. This suggests that the intermolecular beta-sheet of rhIFN-gamma is stabilized by electrostatic interactions that are disrupted at high pressure. For comparison we also studied the effect of temperature. Temperature-induced changes reflect extensive transformation of alpha-helical structure into intermolecular antiparallel beta-sheet, as is usually observed for most proteins.
OBJECTIVE: To assess the heating caused by selected pulsed Doppler and physiotherapy ultrasound beams by measurements made using thermal test objects. METHOD: Thermal test objects were used to measure temperature rises in selected ultrasound fields. These were compared with theoretical predictions based on standard exposure measurements. A separate thermocouple was used to measure heating at the transducer surface. RESULTS: Temperature rises of up to 6 degrees C were measured for Doppler fields using a thermal test object. The attenuation-corrected temperature rises that were measured generally agreed with calculated Thermal Indices. Temperature rises of up to 2 degrees C were observed for physiotherapy ultrasound fields in pulsed operation. CONCLUSION: Significant overlap between the measured temperature rises of selected pulsed Doppler and physiotherapy ultrasound fields was observed.
White Star micropulse technology is a software modification that allows extremely short bursts of ultrasound energy. Studies have shown that this decreases wound heat build-up with the retained efficiency of continuous ultrasound. Decreased energy utilization with improved corneal function and improved nuclear fragment followability appear to be additional benefits.