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  • Comparative Studies. Non-European Languages/Literatures  (13)
  • 1
    Online Resource
    Online Resource
    Determination of tissue injury thresholds from ultrasound in a porcine kidney model
    Acoustical Society of America (ASA) ; 2013
    In:  The Journal of the Acoustical Society of America Vol. 133, No. 5_Supplement ( 2013-05-01), p. 3411-3411
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 133, No. 5_Supplement ( 2013-05-01), p. 3411-3411
    Abstract: Therapeutic ultrasound has an increasing number of applications in urology, including shockwave lithotripsy, stone propulsion, tissue ablation, and hemostasis. However, the threshold of renal injury using ultrasound is unknown. The goal of this study was to determine kidney injury thresholds for a range of intensities between diagnostic and ablative therapeutic ultrasound. A 2 MHz annular array generating spatial peak pulse average intensities (ISPPA) up to 30,000 W/cm2 in water was placed on the surface of in vivo porcine kidneys and focused on the adjacent parenchyma. Treatments consisted of pulses of 100 μs duration triggered every 3 ms for 10 min at various intensities. The perfusion-fixed tissue was scored by three blinded independent experts. Above a threshold of 20,000 W/cm2, the majority of injury observed included emulsification, necrosis, and hemorrhage. Below this threshold, almost all injury presented as focal cell and tubular swelling and/or degeneration. These findings provide evidence for a wide range of potentially therapeutic ultrasound intensities that has a low probability of causing injury. While this study did not examine all combinations of treatment parameters of therapeutic ultrasound, tissue injury appears dose-dependent. [Work supported by NIH DK43881, DK092197, and NSBRI through NASA NCC 9-58.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4805956
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2013
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 2
    Online Resource
    Online Resource
    Acoustic radiation force to reposition kidney stones
    Acoustical Society of America (ASA) ; 2013
    In:  The Journal of the Acoustical Society of America Vol. 133, No. 5_Supplement ( 2013-05-01), p. 3279-3279
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 133, No. 5_Supplement ( 2013-05-01), p. 3279-3279
    Abstract: Our group has introduced transcutaneous ultrasound to move kidney stones in order to expel small stones or relocate an obstructing stone to a nonobstructing location. Human stones and metalized beads (2–8 mm) were implanted ureteroscopically in kidneys of eight domestic swine. Ultrasonic propulsion was performed using a diagnostic imaging transducer and a Verasonics ultrasound platform. Stone propulsion was visualized using fluoroscopy, ultrasound, and the ureteroscope. Successful stone movement was defined as relocating a stone to the renal pelvis, ureteropelvic junction (UPJ), or proximal ureter. Three blinded experts evaluated for histologic injury in control and treatment arms. All stones were moved. 65% (17/26) of stones/beads were moved the entire distance to the renal pelvis (3), UPJ (2), or ureter (12). Average successful procedure per stone required 14±8 min and 23±16 pushes. Each push averaged 0.9 s in duration. Mean interval between pushes was 41±13 s. No gross or histologic kidney damage was identified in six kidneys from exposure to 20 1-s pushes spaced by 33 s. Ultrasonic propulsion is effective with most stones being relocated to the renal pelvis, UPJ, or ureter. The procedure appears safe without evidence of injury. [Work supported by NIH DK43881, DK092197, and NSBRI through NASA NCC 9-58.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4805345
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2013
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 3
    Online Resource
    Online Resource
    Investigation on the effect of specular reflections from stone surface on twinkling artifact
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2538-2538
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2538-2538
    Abstract: The twinkling artifact can highlight kidney stones during ultrasound color Doppler imaging with high sensitivity for stone detection. The mechanism of the twinkling artifact is still under debate. It was reported previously that twinkling appeared distal to the echogenic reflection from the stone surface in cases with no signal saturation. [Lu etal., JASA 129(4), p. 2376]. In this report, the effect of specular reflections on twinkling was investigated. Human kidney stones (5-9 mm in length) were embedded in a polyacrylamide gel phantom. Radio-frequency (RF) data were recorded from pulse-echo ensembles using a software-programmable ultrasound system. The variability within the beamformed Doppler ensemble, which is responsible for twinkling, was traced back to the unbeamformed RF channel data to identify whether variability arose disproportionately on channels receiving the specular reflection. The results showed that the specular reflection did not saturate individual channels and that the variability was observed on most channels with similar magnitude, which indicates that the appearance of twinkling does not rely on the specular reflection from the stone surface. Instead in the beamformer, the varying signals have the appearance of arising from a point source within the stone. [Work supported by NIH DK43881, DK086371, DK092197, and NSBRI through NASA NCC 9-58.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3655140
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 4
    Online Resource
    Online Resource
    Investigation of the effect of signal amplitude on twinkling artifact.
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2376-2376
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2376-2376
    Abstract: Twinkling artifact on color Doppler ultrasound is the color labeling of hard objects, such as kidney stones, in the image. The origin of the artifact is unknown, but clinical studies have shown that twinkling artifact can improve the sensitivity of detection of stones by ultrasound. Although Doppler detection normally correlates changes in phase with moving blood, here the effect of amplitude on the artifact is investigated. Radio-frequency and in-phase and quadrature (IQ) data were recorded by pulse-echo ensembles using a software-programmable ultrasound system. Various hard targets in water and in tissue were insonified with a linear probe, and rectilinear pixel-based imaging was used to minimize beam-forming complexity. In addition, synthesized radio-frequency signals were sent directly into the ultrasound system to separate acoustic and signal processing effects. Artifact was observed both in onscreen and post-processed images, and as high statistical variance within the ensemble IQ data. Results showed that twinkling artifact could be obtained from most solid objects by changing the Doppler gain, yet signal amplitude did not have to be sufficiently high to saturate the receive circuits. In addition, low signal but high time gain compensation created the largest variance. [Work supported by NIH DK43881, DK086371, and NSBRI through NASA NCC 9-58.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3587698
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 5
    Online Resource
    Online Resource
    Autoregressive ultrasound imaging method to enhance kidney stone twinkling and suppress blood flow.
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2376-2376
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2376-2376
    Abstract: “Twinkling” is a widely reported ultrasound artifact whereby kidney stones and other similar calcified, strongly reflective objects appear as turbulent, flowing blood in color and power Doppler. The twinkling artifact has been shown to improve kidney stone detection over B-mode imaging alone, but its use has several limitations. Principally, twinkling can be confused with blood flow, potentially leading to an incorrect diagnosis. Here a new method is reported for explicitly suppressing the display of color from blood flow to enhance and/or isolate the twinkle signal. The method applies an autoregressive model to standard Doppler pulses in order to differentiate tissue, blood flow, and twinkling. The algorithm was implemented on a software-based, open architecture ultrasound system and tested by a sonographer on phantoms and on stones implanted in a live porcine kidney. Stones of 3–10 mm were detected reproducibly while suppressing blood flow in the image. In conclusion, a new algorithm designed to specifically detect stones has been tested and has potential clinical utility especially as efforts are made to reduce radiation exposure on diagnosis and monitoring. [This work was supported by the National Institutes of Health (NIH Grant No. DK43881) and the National Space Biomedical Research Institute through Grant No. NASA NCC 9-58.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3587699
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 6
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    Importance of cochlear health for cochlear-implant function
    Acoustical Society of America (ASA) ; 2015
    In:  Journal of the Acoustical Society of America Vol. 137, No. 4_Supplement ( 2015-04-01), p. 2297-2297
    Details
    In: Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 137, No. 4_Supplement ( 2015-04-01), p. 2297-2297
    Abstract: In humans with cochlear implants, functional measures show considerable variation from one stimulation site to another along the electrode array. Our research has demonstrated that (1) the across-site patterns of the functional data are stable over time but differ across subjects; and (2) the across-site patterns are measure specific. These observations are consistent with the hypotheses that implant performance at a given stimulation site is dependent on specific conditions near the site, and that the various functional measures do not all depend on the same conditions. However, we lack direct evidence as to the specific conditions leading to the site-specific differences in performance in humans. Studies in our guinea pig laboratory and elsewhere have demonstrated highly significant correlations between psychophysical or electrophysiological measures of implant function and anatomical measures of cochlear health. Furthermore, the correlated anatomical features differ across functional measures. Finally, some functional measures that are correlated with anatomical measures of cochlear health in animals are predictive of speech recognition ability in human implant users. The data support efforts to preserve and/or restore the health of the implanted cochlea. [This work was supported by NIH/NIDCD grants R01 DC010786, R01 DC010412, and P30 DC05188, and a contract from MED-EL.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4920384
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2015
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 7
    Online Resource
    Online Resource
    Color-Doppler ultrasound imaging of in situ human kidney stones in a hyperbaric chamber
    Acoustical Society of America (ASA) ; 2016
    In:  Journal of the Acoustical Society of America Vol. 140, No. 4_Supplement ( 2016-10-01), p. 2983-2984
    Details
    In: Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 140, No. 4_Supplement ( 2016-10-01), p. 2983-2984
    Abstract: Overpressure has been shown to reduce the color-Doppler ultrasound twinkling artifact on ex vivo human kidney stones, leading to the hypothesis that surface crevice microbubbles cause twinkling. For the first time, we investigate the effect of overpressure on in situ human kidney stones. Thus far, five human subjects with kidney stones known to twinkle have been imaged with a Philips/ATL P4-2 transducer and Verasonics ultrasound system for 45 minutes in a hyperbaric chamber. Subjects breathed ambient air while exposed to a maximum pressure of 4 atmospheres absolute (ATA), except for a scheduled decompression stop at 1.6 ATA where subjects breathed pure oxygen. Twinkling was quantified in terms of Doppler power over 2 min intervals before pressurization (baseline), at 4 ATA, and at 1.6 ATA. Preliminary results (averaged over 3 of the 5 subjects) indicate no change in twinkling at 4 ATA compared to baseline levels (ratio of Doppler powers = 1.09±0.27). Twinkling almost doubled, though, during the pure oxygen stage at 1.6 ATA compared to baseline levels (ratio of Doppler powers = 1.85±0.58). The increase in twinkling associated with breathing pure oxygen continues to support the crevice microbubble hypothesis. Higher pressures than explored in this study may be needed to reduce twinkling on in situ stones, as was often the case in studies using ex vivo human kidney stones. [Work supported by the National Space Biomedical Research Institute through NASA NCC 9-58 and NIH grants DK043881 and DK092197.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4969238
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2016
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 8
    Online Resource
    Online Resource
    The effect of ambient pressure on the color Doppler ultrasound twinkling artifact
    Acoustical Society of America (ASA) ; 2015
    In:  The Journal of the Acoustical Society of America Vol. 138, No. 3_Supplement ( 2015-09-01), p. 1746-1746
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 138, No. 3_Supplement ( 2015-09-01), p. 1746-1746
    Abstract: Recently, our group discovered that overpressure suppressed the color Doppler ultrasound twinkling artifact on ex vivo calcium oxalate monohydrate (COM) kidney stones, suggesting that trapped microbubbles on the stone surface cause twinkling (Lu et al. 2013). Yet the hypothesis is not fully accepted, partly because bubbles were not observed. Here, we extend the overpressure results to include under-pressure and use high-speed photography to visualize the bubbles. A programmable ultrasound system with Philips/ATL P4-2 transducer was used. Ex vivo COM stones were placed in a hydraulic pressure chamber and imaged acoustically through an acrylic window. The overpressure threshold to diminish twinkling was found to vary significantly, with twinkling eliminated at pressures of 3 ATA (atmospheres absolute) up to & gt;8 ATA, even within the same stone. When the stones were exposed to 0.2 ATA (under-pressure), twinkling increased. High-speed photography during Doppler ultrasound revealed only one instance of an oscillating bubble. However, when stones were exposed repeatedly to a pre-focal, off-axis lithotripter pulse (p+ = 1.5 MPa, p- = 2.5 MPa), stones that twinkled had bubbles emerge from the same location with each pulse whereas stones that did not twinkle had a random bubble distribution. [Work supported by NSBRI through NASA NCC 9-58 and NIH DK043881, DK092197.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4933510
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2015
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 9
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    Online Resource
    Acoustic radiation force applied to the treatment of lower pole kidney stones
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2423-2423
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2423-2423
    Abstract: Lower pole kidney stones have lower rates of clearance after shock wave lithotripsy or ureteroscopy compared to other stone locations. Residual stone fragments, post treatment, often lead to additional morbidity and secondary surgery. We describe the use of acoustic radiation force created by transcutaneous focused ultrasound to manipulate the location of stone fragments within the collecting system in order to facilitate their passage. Artificial and human stones were placed in the lower pole of kidneys of a porcine animal model. An open architecture, software based diagnostic ultrasound system and scanhead were modified to produce roughly 100 μs pulses of up to 16 MPa peak positive pressure in water. Stone motion was observed in real-time with simultaneous imaging through the same scanhead and with fluoroscopy. All stones were seen to move. Stone velocities were on the order of 1 cm/s. Stone displacement distance was up to 3 cm, and operators could generally control the direction of stone movement. No evidence of thermal necrosis or mechanical damage of renal tissue was observed. Thus acoustic radiation force can be used to facilitate lower pole stone fragment clearance. [Work supported by NIH DK43881, DK086371, DK092197, and NSBRI through NASA NCC 9-58.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3654710
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
    detail.hit.zdb_id: 219231-7
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  • 10
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    Online Resource
    SYNTACTIC AND PROSODIC COMPUTATIONS IN THE RESOLUTION OF RELATIVE CLAUSE ATTACHMENT AMBIGUITY BY ENGLISH-FRENCH LEARNERS
    Cambridge University Press (CUP) ; 2008
    In:  Studies in Second Language Acquisition Vol. 30, No. 4 ( 2008-12), p. 453-480
    Details
    In: Studies in Second Language Acquisition, Cambridge University Press (CUP), Vol. 30, No. 4 ( 2008-12), p. 453-480
    Abstract: This study investigates the manner in which syntax, prosody, and context interact when second- and fourth-semester college-level English-French learners process relative clause (RC) attachment to either the first noun phrase (NP1) or the second noun phrase (NP2) in complex nominal expressions such as le secrétaire du psychologue qui se promène (au centre ville) “the secretary of the psychologist who takes a walk (downtown).” Learners' interpretations were affected by the length of the RC, specifically its phonological weight. Effects of intonation contour were found only in a subset of learners. In a response time (RT) experiment that manipulated contexts, fourth-semester learners showed a final bias for NP1 attachment in interpretation but an initial RT bias for NP2 attachment. Second-semester learners also produced a NP2 attachment bias in RTs, but no asymmetry in interpretation was found. We argue that the processing of RC attachment by English-French learners requires a task-specific algorithm that implicates autonomous syntactic and prosodic computations and specific interactions among them.
    Type of Medium: Online Resource
    ISSN: 0272-2631 , 1470-1545
    URL: Article
    DOI: 10.1017/S0272263108080728
    RVK:
    EQ 1000
    RVK:
    HC 1000
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2008
    detail.hit.zdb_id: 435303-1
    detail.hit.zdb_id: 2002746-1
    SSG: 7,11
    SSG: 5,3
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