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231224s2015 xx |||||o 00| ||eng c |
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|a pubmed25n0828.xml
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|a (DE-627)NLM248640062
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|a (NLM)25935932
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|a DE-627
|b ger
|c DE-627
|e rakwb
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|a eng
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| 100 |
1 |
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|a Koppolu, Sujeethraj
|e verfasserin
|4 aut
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| 245 |
1 |
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|a Correlation of rupture dynamics to the nonlinear backscatter response from polymer-shelled ultrasound contrast agents
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|c 2015
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|a Text
|b txt
|2 rdacontent
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| 337 |
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|a ƒaComputermedien
|b c
|2 rdamedia
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| 338 |
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|a ƒa Online-Ressource
|b cr
|2 rdacarrier
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| 500 |
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|a Date Completed 17.11.2015
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|a Date Revised 18.09.2019
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|a published: Print
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|a Citation Status MEDLINE
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|a Polymer-shelled ultrasound contrast agents (UCAs) may expel their encapsulated gas subject to ultrasound-induced shell buckling or rupture. Nonlinear oscillations of this gas bubble can produce a subharmonic component in the ultrasound backscatter. This study investigated the relationship between this gas-release mechanism and shell-thickness-to-radius ratios (STRRs) of polymer-shelled UCAs. Three types of polylactide-shelled UCAs with STRRs of 7.5, 40, and 100 nm/μm were studied. Each UCA population had a nominal mean diameter of 2 μm. UCAs were subjected to increasing static overpressure ranging from 2 to 330 kPa over a duration of 2 h in a custom-designed test chamber while being imaged using a 200× magnification video microscope at a frame rate of 5 frames/s. Digitized video images were binarized and processed to obtain the cross-sectional area of individual UCAs. Integration of the normalized cross-sectional area over normalized time, defined as buckling factor (Bf), provided a dimensionless parameter for quantifying and comparing the degree of pre-rupture buckling exhibited by the UCAs of different STRRs in response to overpressure. The UCAs with an STRR of 7.5 nm/μm exhibited a distinct shell-buckling phase before shell rupture (Bf < 1), whereas the UCAs with higher STRRs (40 and 100 nm/μm) did not undergo significant prerupture buckling (Bf ≈ 1). The difference in the overpressure response was correlated with the subharmonic response produced by these UCAs. When excited using 20-MHz ultrasound, individual UCAs (N = 3000) in populations that did not exhibit a buckling phase produced a subharmonic response that was an order of magnitude greater than the UCA population with a prominent pre-rupture buckling phase. These results indicate the mechanism of gas expulsion from these UCAs might be a relevant factor in determining the level of subharmonic response in response to high-frequency ultrasound
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|a Journal Article
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|a Research Support, N.I.H., Extramural
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| 650 |
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|a Contrast Media
|2 NLM
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|a Polymers
|2 NLM
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| 700 |
1 |
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|a Chitnis, Parag V
|e verfasserin
|4 aut
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| 700 |
1 |
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|a Mamou, Jonathan
|e verfasserin
|4 aut
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| 700 |
1 |
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|a Allen, John S
|e verfasserin
|4 aut
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| 700 |
1 |
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|a Ketterling, Jeffrey A
|e verfasserin
|4 aut
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| 773 |
0 |
8 |
|i Enthalten in
|t IEEE transactions on ultrasonics, ferroelectrics, and frequency control
|d 1986
|g 62(2015), 3 vom: 02. März, Seite 494-501
|w (DE-627)NLM098181017
|x 1525-8955
|7 nnns
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| 773 |
1 |
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|g volume:62
|g year:2015
|g number:3
|g day:02
|g month:03
|g pages:494-501
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|a GBV_USEFLAG_A
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|a GBV_ILN_350
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|a AR
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| 952 |
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|d 62
|j 2015
|e 3
|b 02
|c 03
|h 494-501
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