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In spite of the high added value and tremendous output from duck processing industries, duck liver (DLv) is underutilized and a major factor is related to its prominent off-flavor perception which hampers the consumption and processing attributes. This work was designed to investigate the impact of low-frequency ultrasound (US) pretreatments on the headspace volatilome evolution of DLv and its isolated protein (DLvP) microstructure, aiming at exploring the potential of US technology to inhibit off-flavor perception and possible mechanisms behind. Results suggested that US pretreatment resulted in decreased lipid oxidation and off-flavor perception, simultaneously without significantly causing physicochemical influence including texture, pH and color. US induced obvious tertiary structural changes of DLvP, as revealed by the intrinsic fluorescence and surface hydrophobicity (H0), whereas the SH, S-S, secondary structure and molecular weight of DLvP remained unaffected, suggesting the presence of molten globule state (MG-state) under ultrasonic conditions. Besides, the headspace contents of flavor compounds, mainly aldehydes and alcohols, were significantly decreased whereas acids were increased. Multivariate analysis suggested an obvious US-induced effect on the volatilome evolution of DLv samples. Discriminant analysis recognized the aroma compounds including aldehydes and alkenals as the major contributors leading to the change of olfactory characteristics of DLv after ultrasonic treatment. Correlation analysis demonstrated the positive relationship between the volatile markers variation and the increased H0 values, a characteristic attribute of MG-state protein. The results obtained in this work suggested that US technology matched with suitable parameters could be a very promising approach to modulate the off-flavor perception of liver products by altering DLvP conformation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose: To demonstrate the dosimetric effects of observer variability in defining the prostate and critical organs, using Tissue Harmonic (H) ultrasound imaging mode for permanent seed implant brachytherapy., Methods: Images were acquired using a B -K medical 8848 probe with Brightness (B) and H mode for ten prostate brachytherapy patients. The prostate, rectum and urethra were contoured independently by five observers. The clinically used treatment plans based on B mode imaging fulfilling the dosimetric criteria were applied on these contours. Dosimetric parameters (prostate: D90, V100 and V200; rectum: V100; urethra: V140, V150 and V160) were computed using SPOT PRO™ planning system. Interobserver variability in dosimetric parameters was tested using standard deviations as percentages of means., Results: Two-factor analysis of variances showed significant (p<0.05) interobserver variability in all dosimetric parameters for both modes. Interobserver agreement in dosimetric parameters improves in H mode due to improved interobserver consistency in contouring these organs on H mode images compared to B mode. There is no significant difference observed (paired student t test, p>0.05) in the mean values of dosimetric parameters in H and B mode for prostate and critical organs., Conclusions: H mode due to its better image quality helped to improve the interobserver agreement in contouring the prostate and critical organs and hence better interobserver consistency in all dosimetric parameter. Because the difference in the mean value of dosimetric parameters between two imaging modes is not statistically significant, H mode does not appear to offer any clinical advantages in terms of improving the dosimetric outcome., (© 2012 American Association of Physicists in Medicine.)

Purpose: Ultrasound Doppler velocity measurements are routinely used to determine the severity of a stenosis in the carotid, renal or peripheral arteries. The objective of this study is to investigate and demonstrate the relationship between Doppler velocity measurements and transducer degradation conditions encountered in a clinical environment., Methods: Assessing transducer performance was accomplished using the First Call aPerio Test System transducer analyzer (Sonora Medical Systems, Longmont, CO). This system was used to conduct 1,145 semi-annual transducer assessments at 7 clinical sites from September 2007 to February 2012 as part of a comprehensive quality control program. The results were evaluated to determine the degree of transducer degradation encountered in the clinical environment. A Siemens Acuson S2000 (Siemens AG, Erlangen, Germany) ultrasound system was employed with the 1425A LE Doppler Flow System (Gammex, Middleton, WI) to determine Doppler velocity measurements. A transducer fixation device was fabricated to provide accurate, repeatable velocity measurements. Transducers with the most severe degradation were evaluated by comparing velocity measurements to those without defects. Using several matched transducer pairs, simulated failure modes were tested. The Doppler measured time-average mean (TAMn) and time-average maximum (TAMx) velocities were obtained and reported., Results: This investigation found that 4.5% of the transducers surveyed during this 5-year period of time failed at least one acceptance criteria. Many (346 or 30%) had at least one defect. Typical findings include dead elements, lens delamination, wire cuts, and capacitance shorts. Only the most severe transducer defects and degradation conditions resulted in a noticeable deviation in the velocity measurements. Simulated transducer degradation testing confirmed this finding., Conclusions: The relationship between Doppler velocity measurements and transducer degradation conditions is limited, becoming significant for only the most severe degradation conditions. Based on our experience, this level of transducer degradation is rarely encountered in the clinical environment., (© 2012 American Association of Physicists in Medicine.)