@article{suo_govind_gu_dayton_jing_2019, title={Dynamic assessment of dual-frequency microbubble-mediated sonothrombolysis in vitro}, volume={125}, ISSN={["1089-7550"]}, DOI={10.1063/1.5083908}, abstractNote={Optimizing the use of high intensity focused ultrasound (HIFU) for recanalization of occluded blood vessels is an actively researched area. This yields an alternative therapy to the use of thrombolytic drugs in the treatment of ischemic stroke. HIFU treatment, used in conjunction with microbubbles (MBs) in the fluid stream, serves to augment the dissipation of the blood clot. In this study, using an in vitro approach, we implement a flow system to simulate the dynamic dispersion of blood clots using single-frequency focused ultrasound (SFFU) and dual-frequency focused ultrasound (DFFU). The effects of permutations of acoustic power and driving frequency (SFFU vs. DFFU) on the rate of disintegration and site-specific lytic action are quantified under the influence of fluid akin to that in a blood vessel, for specific microbubble concentrations. It is found that dual-frequency excitation in general produces a faster rate of clot dissipation in comparison to single-frequency excitation, and this observation is corroborated by cavitation signal detection. Our observations indicate that accelerated thrombolysis may be realized by the inertial cavitation threshold of DFFU being lower than that of SFFU. Furthermore, the thrombolytic effect with variance in microbubble concentration is studied for a fixed acoustic power. The efficacy of DFFU is not found to vary appreciably with an increase in microbubble concentration from 108 MBs/ml to 109 MBs/ml, possibly due to acoustic shadowing induced at increased concentrations.}, number={8}, journal={JOURNAL OF APPLIED PHYSICS}, author={Suo, Dingjie and Govind, Bala and Gu, Juanjuan and Dayton, Paul A. and Jing, Yun}, year={2019}, month={Feb} }
 @article{li_duan_semenov_kim_2017, title={Electrical switching of antiferromagnets via strongly spin-orbit coupled materials}, volume={121}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4974027}, DOI={10.1063/1.4974027}, abstractNote={Electrically controlled ultra-fast switching of an antiferromagnet (AFM) is shown to be realizable by interfacing it with a material of strong spin-orbit coupling. The proximity interaction between the sublattice magnetic moments of a layered AFM and the spin-polarized free electrons at the interface offers an efficient way to manipulate antiferromagnetic states. A quantitative analysis, using the combination with a topological insulator as an example, demonstrates highly reliable 90° and 180° rotations of AFM magnetic states under two different mechanisms of effective torque generation at the interface. The estimated switching speed and energy requirement are in the ps and aJ ranges, respectively, which are about two-three orders of magnitude better than the ferromagnetic counterparts. The observed differences in the magnetization dynamics may explain the disparate characteristic responses. Unlike the usual precessional/chiral motions in the ferromagnets, those of the AFMs can essentially be described as a damped oscillator with a more direct path. The impact of random thermal fluctuations is also examined.}, number={2}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Li, Xi-Lai and Duan, Xiaopeng and Semenov, Yuriy G. and Kim, Ki Wook}, year={2017}, month={Jan}, pages={023907} }
 @article{suo_govind_zhang_jing_2018, title={Numerical investigation of the inertial cavitation threshold under multi-frequency ultrasound}, volume={41}, ISSN={["1873-2828"]}, DOI={10.1016/j.ultsonch.2017.10.004}, abstractNote={Through the introduction of multi-frequency sonication in High Intensity Focused Ultrasound (HIFU), enhancement of efficiency has been noted in several applications including thrombolysis, tissue ablation, sonochemistry, and sonoluminescence. One key experimental observation is that multi-frequency ultrasound can help lower the inertial cavitation threshold, thereby improving the power efficiency. However, this has not been well corroborated by the theory. In this paper, a numerical investigation on the inertial cavitation threshold of microbubbles (MBs) under multi-frequency ultrasound irradiation is conducted. The relationships between the cavitation threshold and MB size at various frequencies and in different media are investigated. The results of single-, dual and triple frequency sonication show reduced inertial cavitation thresholds by introducing additional frequencies which is consistent with previous experimental work. In addition, no significant difference is observed between dual frequency sonication with various frequency differences. This study, not only reaffirms the benefit of using multi-frequency ultrasound for various applications, but also provides a possible route for optimizing ultrasound excitations for initiating inertial cavitation.}, journal={ULTRASONICS SONOCHEMISTRY}, author={Suo, Dingjie and Govind, Bala and Zhang, Shengqi and Jing, Yun}, year={2018}, month={Mar}, pages={419–426} }
 @article{xie_shen_wang_li_suo_popa_jing_cummer_2016, title={Acoustic Holographic Rendering with Two-dimensional Metamaterial-based Passive Phased Array}, volume={6}, ISSN={["2045-2322"]}, DOI={10.1038/srep35437}, abstractNote={AbstractAcoustic holographic rendering in complete analogy with optical holography are useful for various applications, ranging from multi-focal lensing, multiplexed sensing and synthesizing three-dimensional complex sound fields. Conventional approaches rely on a large number of active transducers and phase shifting circuits. In this paper we show that by using passive metamaterials as subwavelength pixels, holographic rendering can be achieved without cumbersome circuitry and with only a single transducer, thus significantly reducing system complexity. Such metamaterial-based holograms can serve as versatile platforms for various advanced acoustic wave manipulation and signal modulation, leading to new possibilities in acoustic sensing, energy deposition and medical diagnostic imaging.}, journal={SCIENTIFIC REPORTS}, author={Xie, Yangbo and Shen, Chen and Wang, Wenqi and Li, Junfei and Suo, Dingjie and Popa, Bogdan-Ioan and Jing, Yun and Cummer, Steven A.}, year={2016}, month={Oct} }
 @article{suo_guo_lin_jiang_jing_2015, title={Thrombolysis using multi-frequency high intensity focused ultrasound at MHz range: an in vitro study}, volume={60}, ISSN={["1361-6560"]}, DOI={10.1088/0031-9155/60/18/7403}, abstractNote={High intensity focused ultrasound (HIFU) based thrombolysis has emerged as a promising drug-free treatment approach for ischemic stroke. The large amount of acoustic power required by this approach, however, poses a critical challenge to the future clinical translation. In this study, multi-frequency acoustic waves at MHz range (near 1.5 MHz) were introduced as HIFU excitations to reduce the required power for treatment as well as the treatment time. In vitro bovine blood clots weighing around 150 mg were treated by single-frequency and multi-frequency HIFU. The pulse length was 2 ms for all experiments except the ones where the duty cycle was changed. It was found that dual-frequency thrombolysis efficiency was statistically better than single-frequency under the same acoustic power and excitation condition. When varying the acoustic power but fixing the duty cycle at 5%, it was found that dual-frequency ultrasound can save almost 30% power in order to achieve the same thrombolysis efficiency. In the experiment where the duty cycle was increased from 0.5% to 10%, it was shown that dual-frequency ultrasound can achieve the same thrombolysis efficiency with only half of the duty cycle of single-frequency. Dual-frequency ultrasound could also accelerate the thrombolysis by a factor of 2–4 as demonstrated in this study. No significant differences were found between dual-frequencies with different frequency differences (0.025, 0.05, and 0.1 MHz) and between dual-frequency and triple-frequency. The measured cavitation doses of dual-frequency and triple-frequency excitations were at about the same level but both were significantly higher than that of single-frequency.}, number={18}, journal={PHYSICS IN MEDICINE AND BIOLOGY}, author={Suo, Dingjie and Guo, Sijia and Lin, Weili and Jiang, Xiaoning and Jing, Yun}, year={2015}, month={Sep}, pages={7403–7418} }
 @article{guo_suo_jing_jiang_frank_lin_2014, title={Thrombolysis enhanced by dual-frequency high-intensity focused ultrasound}, ISSN={["1948-5719"]}, DOI={10.1109/ultsym.2014.0541}, abstractNote={It has been demonstrated that high-intensity focused ultrasound can be an efficient method to induce thrombolysis. Excessive thermal effect on neighboring tissue is however a concern. The goal of this work is to test the efficacy of dual-frequency ultrasound-induced thrombolysis, with the aim to reduce the acoustic power required to achieve the same lysis rate (mass loss of blood clots over time) as single-frequency ultrasound. In vitro clots of mouse blood were prepared and placed at the focus of two piezoelectric ultrasound transducers (center frequencies were 0.95 MHz and 1.5 MHz, respectively). 0.65 W ultrasound waves with 10% duty cycle were employed in both single- and dual-frequency ultrasound exposures. The mass losses of the clots were recorded to obtain the lysis rate after each test. It was found that dual-frequency results in more efficient thrombolysis. Cavitation bubble modeling was also conducted for both single- and dual-frequency ultrasound to explain the experimental founding.}, journal={2014 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS)}, author={Guo, Sijia and Suo, Dingjie and Jing, Yun and Jiang, Xiaoning and Frank, Jonathan and Lin, Weili}, year={2014}, pages={2173–2176} }