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Abstract
Enterovirus 71 (EV71), a member of the Enterovirus genus in the Picornaviridae family, has become an emergent infectious disease worldwide, most notably in Asia. As a neurotropic virus, EV71 infection occasionally causes neurological diseases with pulmonary edema, which is fatal for children. In this review, we examine the epidemiology of EV71, with three waves of increased EV71 activity since the 1970s and discuss the genotypic changes in phylogeny between the outbreaks or epidemics. Genetic changes including mutations and recombinations as well as the diversity of antigenic properties among EV71 strains in various outbreaks are described. Furthermore, the impact of genetic changes on viral pathogenesis and vaccine candidate selection are addressed. In conclusion, these genetic and antigenic investigations of EV71 evolution have provided us with new insight into the trend of EV71 epidemiology, which may contribute to a better understanding of the viral pathogenesis and vaccine development.
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Affiliation(s)
- Sheng-Wen Huang
- The Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 701, Taiwan
| | - David Kiang
- Microbiology Section, Food and Drug Laboratory Branch, California Department of Public Health, CA 94804-6403, USA
| | - Derek J Smith
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
- Department of Virology, Erasmus Medical Centre, Rotterdam 3015 GE, Netherlands
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892-2220, USA
| | - Jen-Ren Wang
- The Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 701, Taiwan
- Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University
- Division of Infectious Diseases, National Health Research Institutes, Tainan 701, Taiwan
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Tsai HP, Huang SW, Wu FL, Kuo PH, Wang SM, Liu CC, Su IJ, Wang JR. An echovirus 18-associated outbreak of aseptic meningitis in Taiwan: epidemiology and diagnostic and genetic aspects. J Med Microbiol 2011; 60:1360-1365. [PMID: 21546563 DOI: 10.1099/jmm.0.027698-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In 2006, an outbreak of aseptic meningitis was noted in Taiwan. From January to October 2006, a total of 3283 specimens collected from patients with viral infection, including 173 cerebrospinal fluid (CSF) samples, were examined for virus isolation and identification. Overall, 339 enterovirus (EV)-positive cases were identified by virus culture: echovirus 18 (E18) formed the majority (27.4 %, 93 cases), followed by coxsackievirus B2 (13.8 %, 47 cases) and coxsackievirus A2 (10.8 %, 37 cases). The manifestations of the 93 E18 cases were aseptic meningitis (44.1 %), viral exanthema (23.6 %), acute tonsillitis (15.1 %), acute pharyngitis (14.0 %), acute gastritis (11.8 %), herpangina (7.5 %) and bronchopneumonia (5.3 %). Of 107 E18 isolates identified, 100, 62.5 and 19 % were obtained following culture in RD, MRC-5 and A549 cells, respectively. E18 was identified most frequently from throat swabs (67.2 %) and less frequently from stool samples (15.9 %) and CSF (16.8 %). The detection rate of E18 was 78.2 % from CSF, 50 % from stool samples and 22.9 % from throat swabs. Phylogenetic relationships among the E18 strains were examined. Analysis of the partial VP1 gene showed 3.7-23.8 % variation in sequence compared with sequences from GenBank and, notably, the amino acid change V152S was detected in a protruding loop within the VP1 protein. These results indicate that a genetic variant of E18 was circulating and caused an outbreak of aseptic meningitis in Taiwan in 2006.
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Affiliation(s)
- Huey-Pin Tsai
- Department of Pathology, National Cheng Kung University Medical Center, Tainan, Taiwan, ROC
| | - Sheng-Wen Huang
- Institute of Basic Medical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Feng-Ling Wu
- Department of Pathology, National Cheng Kung University Medical Center, Tainan, Taiwan, ROC
| | - Pin-Hwa Kuo
- Department of Pathology, National Cheng Kung University Medical Center, Tainan, Taiwan, ROC
| | - Shih-Min Wang
- Division of Infectious Diseases, National Health Research Institutes, Tainan, Taiwan, ROC.,Department of Emergency, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Ching-Chuan Liu
- Division of Infectious Diseases, National Health Research Institutes, Tainan, Taiwan, ROC.,Department of Pediatrics, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Ih-Jen Su
- Division of Infectious Diseases, National Health Research Institutes, Tainan, Taiwan, ROC.,Department of Pathology, National Cheng Kung University Medical Center, Tainan, Taiwan, ROC
| | - Jen-Ren Wang
- Department of Pathology, National Cheng Kung University Medical Center, Tainan, Taiwan, ROC.,Institute of Basic Medical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.,Division of Infectious Diseases, National Health Research Institutes, Tainan, Taiwan, ROC.,Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
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53
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Chen JC, Rajendran K, Chang YH, Huang SW, Chern YT. Highly transparent and organosoluble polyimides derived from 2,2′-disubstituted-4,4′-oxydianilines. J Appl Polym Sci 2011. [DOI: 10.1002/app.33520] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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54
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Huang SW, Xiang DK, Huang L, Chen BL, An BQ, Li GF, Luo ZY. Influence of GGCX genotype on warfarin dose requirements in Chinese patients. Thromb Res 2010; 127:131-4. [PMID: 21195460 DOI: 10.1016/j.thromres.2010.10.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 10/12/2010] [Accepted: 10/26/2010] [Indexed: 11/25/2022]
Abstract
INTRODUCTION It has been widely accepted that genetic factors were the major sources of the variation in warfarin dose. This study is intended to investigate whether the 3261G>A variation in GGCX gene influences stable warfarin dose in Chinese patient population. MATERIALS AND METHODS A total of 217 patients with stable warfarin dose were enrolled. Genomic DNA was extracted from each subject and the genotype of GGCX 3261G>A was determined by using of denaturing high-performance liquid chromatography (DHPLC). Least significant difference tests (LSDs) were used to compare dose with genotypes. Analysis of variance (ANVOA) was used to calculate the proportion of warfarin dose that could be explained by variation in genotype. RESULTS In the total of 217 subjects, 84 patients (38.7%) were GG homozygote, whereas 117 (53.9%) were GA heterozygote and 16 (7.4%) were AA homozygote. Patients with the GGCX 3261AA genotype had a significantly higher average daily maintenance dose (3.39 ± 1.40 mg) than those with the GG genotype (2.69 ± 1.07 mg; P=0.027), and GGCX 3261G>A explains 2.3% of the univariate warfarin dose variance. CONCLUSION GGCX 3261G>A may affect warfarin dose requirements, and showed a small but significant effect on warfarin dose in a Chinese patient population.
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Affiliation(s)
- Sheng-Wen Huang
- Department of Laboratory, Guizhou Provincial People's Hospital, No.83 East Zhongshan Road, Guiyang 550002, Guizhou, PR China.
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55
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Wang LP, Huang SW, Wang SS, Wang C, Mou TY, Zhong M. Mutation Screening of the AT-III Gene in Pregnant and Post-Partum Women With Venous Thromboembolism by DHPLC. Lab Med 2010. [DOI: 10.1309/lmwlz182fjrfyyft] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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56
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Jia C, Olafsson R, Huang SW, Kolias TJ, Kim K, Rubin JM, Xie H, O'Donnell M. Comparison of 2-D speckle tracking and tissue Doppler imaging in an isolated rabbit heart model. IEEE Trans Ultrason Ferroelectr Freq Control 2010; 57:2491-2502. [PMID: 21041136 DOI: 10.1109/tuffc.2010.1715] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Ultrasound strain imaging has been proposed to quantitatively assess myocardial contractility. Cross-correlation-based 2-D speckle tracking (ST) and auto-correlation-based tissue Doppler imaging (TDI) [often called Doppler tissue imaging (DTI)] are competitive ultrasound techniques for this application. Compared with 2-D ST, TDI, as a 1-D method, is sensitive to beam angle and suffers from low strain signal-to-noise ratio because a high pulse repetition frequency is required to avoid aliasing in velocity estimation. In addition, ST and TDI are fundamentally different in the way that physical parameters such as the mechanical strain are derived, resulting in different estimation accuracy and interpretation. In this study, we directly compared the accuracy of TDI and 2-D ST estimates of instantaneous axial normal strain and accumulated axial normal strain using a simulated heart. We then used an isolated rabbit heart model of acute ischemia produced by left descending anterior artery ligation to evaluate the performance of the two methods in detecting abnormal motion. Results showed that instantaneous axial normal strains derived using TDI (0.36% error) were less accurate with larger variance than those derived from 2-D ST (0.08% error) given the same spatial resolution. In addition to poorer accuracy, accumulated axial normal strain estimates derived using TDI suffered from bias, because the accumulation method for TDI cannot trace along the actual tissue displacement path. Finally, we demonstrated the advantage 2-D ST has over TDI to reduce dependency on beam angle for lesion detection by estimating strains based on the principal stretches and their corresponding principal axes.
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Affiliation(s)
- Congxian Jia
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
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57
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Jin Y, Jia C, Huang SW, O'Donnell M, Gao X. Multifunctional nanoparticles as coupled contrast agents. Nat Commun 2010; 1:41. [PMID: 20975706 DOI: 10.1038/ncomms1042] [Citation(s) in RCA: 420] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 06/29/2010] [Indexed: 11/09/2022] Open
Abstract
Engineering compact imaging probes with highly integrated modalities is a key focus in bionanotechnology and will have profound impact on molecular diagnostics, imaging and therapeutics. However, combining multiple components on a nanometre scale to create new imaging modalities unavailable from individual components has proven to be challenging. In this paper, we demonstrate iron oxide and gold-coupled core-shell nanoparticles (NPs) with well-defined structural characteristics (for example, size, shell thickness and core-shell separation) and physical properties (for example, electronic, magnetic, optical, thermal and acoustic). The resulting multifunctional nanoprobes not only offer contrast for electron microscopy, magnetic resonance imaging and scattering-based imaging but, more importantly, enable a new imaging mode, magnetomotive photoacoustic imaging, with remarkable contrast enhancement compared with photoacoustic images using conventional NP contrast agents.
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Affiliation(s)
- Yongdong Jin
- Department of Bioengineering, University of Washington, William H Foege Building N530M, Seattle, Washington 98195, USA
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58
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Abstract
A photoacoustic correlation technique, inspired by its optical counterpart-the fluorescence correlation spectroscopy (FCS)-was tested for the first time, to our knowledge, to demonstrate the feasibility of low-speed flow measurement based on photoacoustic signal detection. A pulsed laser was used to probe the flow of light-absorbing beads. A photoacoustic correlation system of 0.8 s temporal resolution was built and flow speeds ranging from 249 to 14.9 microm/s with corresponding flow times from 4.42 to 74.1 s were measured. The experiment serves as a proof of concept for photoacoustic correlation spectroscopy, which may have many potential applications similar to the FCS.
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Affiliation(s)
- Sung-Liang Chen
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109
| | - Tao Ling
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109
| | - Sheng-Wen Huang
- Department of Bioengineering, University of Washington, Seattle, WA 98195
| | - Hyoung Won Baac
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109
| | - L. Jay Guo
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109
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59
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Chen SL, Ling T, Huang SW, Baac HW, Chang YC, Guo LJ. Photoacoustic correlation technique for low-speed flow measurement. Proc SPIE Int Soc Opt Eng 2010; 7564:75642I. [PMID: 20689645 DOI: 10.1117/12.840123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
A photoacoustic correlation spectroscopy (PACS) technique was proposed for the first time. This technique is inspired by its optical counterpart-the fluorescence correlation spectroscopy (FCS), which is widely used in the characterization of the dynamics of fluorescent species. The fluorescence intensity is measured in FCS while the acoustic signals are detected in PACS. To proof of concept, we demonstrated the flow measurement of light-absorbing beads probed by a pulsed laser. A PACS system with temporal resolution of 0.8 sec was built. Polymer microring resonators were used to detect the photoacoustic signals, which were then signal processed and used to obtain the autocorrelation curves. Flow speeds ranging from 249 to 15.1 μm/s with corresponding flow time from 4.42 to 72.5 sec were measured. The capability of low-speed flow measurement can potentially be used for detecting blood flow in relatively deep capillaries in biological tissues. Moreover, similar to FCS, PACS may have many potential applications in studying the dynamics of photoacoustic beads.
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Affiliation(s)
- Sung-Liang Chen
- Dept. of Electrical Engineering and Computer Science, Univ. of Michigan, Ann Arbor, MI USA 48109
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60
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Baac HW, Ling T, Ashkenazi S, Huang SW, Guo LJ. Photo-acoustic concave transmitter for generating high frequency focused ultrasound. Proc SPIE Int Soc Opt Eng 2010; 7564:75642M. [PMID: 20689643 DOI: 10.1117/12.841089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We present a photo-acoustic concave transmitter to generate and subsequently focus high frequency ultrasound. Owing to a short time-duration of pulse laser beam, high frequency acoustic waves and tight focusing can be easily achieved. The transmitter consists of a light-absorbing film coated on a concave spherical structure. For detection, we used an optical microring ultrasound detector capable of covering a broadband and high frequency spectrum of photo-acoustic source. A spot width of ∼44 μm was obtained at the focal plane. As the finite size and the specific shape of the microring cause a geometrical effect on the detection process, especially for high frequency components, we performed a 2-D spatial signal processing to remove this effect and extract a pure pressure distribution. The aperture for acoustic focusing could be optically controlled by changing the size of pulse laser beam.
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Affiliation(s)
- Hyoung Won Baac
- Dept. of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109 USA
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61
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Chen SL, Huang SW, Ling T, Ashkenazi S, Guo LJ. Polymer microring resonators for high-sensitivity and wideband photoacoustic imaging. IEEE Trans Ultrason Ferroelectr Freq Control 2009; 56:2482-91. [PMID: 19942534 PMCID: PMC2848162 DOI: 10.1109/tuffc.2009.1335] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Polymer microring resonators have been exploited for high-sensitivity and wideband photoacoustic imaging. To demonstrate high-sensitivity ultrasound detection, highfrequency photoacoustic imaging of a 49-microm-diameter black bead at an imaging depth of 5 mm was imaged photoacoustically using a synthetic 2-D array with 249 elements and a low laser fluence of 0.35 mJ/cm(2). A bandpass filter with a center frequency of 28 MHz and a bandwidth of 16 MHz was applied to all element data but without signal averaging, and a signal-to-noise ratio of 16.4 dB was obtained. A wideband detector response is essential for imaging reconstruction of multiscale objects, e.g., various sizes of tissues, by using a range of characteristic acoustic wavelengths. A simulation of photoacoustic tomography of beads shows that objects with their boundaries characteristic of high spatial frequencies and the inner structure primarily of low spatial frequency components can be faithfully reconstructed using such a detector. Photoacoustic tomography experiments of 49- and 301-microm-diameter beads were presented. A high resolution of 12.5 microm was obtained. The boundary of a 301-microm bead was imaged clearly. The results demonstrated that the high sensitivity and broadband response of polymer microring resonators have potential for high resolution and high-fidelity photoacoustic imaging.
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Affiliation(s)
- Sung-Liang Chen
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI
| | - Sheng-Wen Huang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI; Bioengineering Department, University of Washington, Seattle, WA
| | - Tao Ling
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI
| | - Shai Ashkenazi
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI; Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN
| | - L. Jay Guo
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI
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62
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Won Baac H, Ling T, Huang SW, Ashkenazi S, Guo LJ. Characterization of optical microring ultrasound detector by using a high frequency focused photoacoustic transmitter. Appl Phys Lett 2009; 95:144105. [PMID: 19902003 PMCID: PMC2774348 DOI: 10.1063/1.3243337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 08/26/2009] [Indexed: 05/28/2023]
Abstract
We characterize a response of optical microring resonator to high frequency focused ultrasound. To properly evaluate the response over high frequency and broadband spectrum, we use a photoacoustic concave transmitter generating and subsequently focusing the ultrasound. A detected focused profile reveals two types of spatial peaks due to the special ring-shaped detector geometry interacting with the high frequency focused ultrasound. Spectral analysis shows that those peaks are contributed by the main and the side lobes of focused ultrasound, respectively. Experimental focal widths agree with theoretical values within +/-2 mum error, which can be attributed to the narrow width of waveguide.
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63
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Jia C, Olafsson R, Kim K, Kolias TJ, Rubin JM, Weitzel WF, Witte RS, Huang SW, Richards MS, Deng CX, O'Donnell M. Two-dimensional strain imaging of controlled rabbit hearts. Ultrasound Med Biol 2009; 35:1488-501. [PMID: 19616362 PMCID: PMC2731831 DOI: 10.1016/j.ultrasmedbio.2009.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 03/20/2009] [Accepted: 04/08/2009] [Indexed: 05/04/2023]
Abstract
Ultrasound strain imaging using 2-D speckle tracking has been proposed to quantitatively assess changes in myocardial contractility caused by ischemia. Its performance must be demonstrated in a controlled model system as a step toward routine clinical application. In this study, a well-controlled 2-D cardiac elasticity imaging technique was developed using two coplanar and orthogonal linear probes simultaneously imaging an isolated retroperfused rabbit heart. Acute ischemia was generated by left anterior descending (LAD) artery ligation. An excitation-contraction decoupler, 2,3-butanedione monoxime, was applied at a 4-mM concentration to reversibly reduce myocardial contractility. Results using a single probe demonstrate that directional changes in the in-plane principal deformation axes can help locate the bulging area as a result of LAD ligation, which matched well with corresponding Evans Blue staining, and strains or strain magnitude, based on principal stretches, can characterize heart muscle contractility. These two findings using asymmetric displacement accuracy (i.e., normal single-probe measurements with good axial but poor lateral estimates) were further validated using symmetric displacement accuracy (i.e., dual-probe measurements using only accurate axial tracking estimates from each). However, the accuracy of 2-D cardiac strain imaging using a single probe depends on the probe's orientation because of the large variance in lateral displacement estimates.
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Affiliation(s)
- Congxian Jia
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, 48109-2099, USA.
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64
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Abstract
We present differential-absorption photoacoustic imaging, which detects the difference between transient and ground-state absorption, for contrast enhancement based on suppressing undesired objects. Two tubes were imaged. One contains a Pt(II) octaethylporphine (PtOEP) dye solution and serves as an object of interest, while the other contains an IR-783 (from Sigma-Aldrich) dye solution and serves as an object to suppress. Although the IR-783 tube dominates the conventional photoacoustic image, it is suppressed by 43 dB and consequently significantly overwhelmed by the PtOEP tube in the differential-absorption photoacoustic image. Imaging depth in this mode is also discussed.
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Affiliation(s)
- Sheng-Wen Huang
- Department of Bioengineering, University of Washington, 1705 NE Pacific Street, Seattle, Washington 98195, USA.
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65
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Huang L, Petrank Y, Huang SW, Jia C, O'Donnell M. Phase rotation methods in filtering correlation coefficients for ultrasound speckle tracking. IEEE Trans Ultrason Ferroelectr Freq Control 2009; 56:1368-82. [PMID: 19574148 PMCID: PMC3889145 DOI: 10.1109/tuffc.2009.1193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In speckle-tracking-based myocardial strain imaging, large interframe/volume peak-systolic strains cause peak hopping artifacts separating the highest correlation coefficient peak from the true peak. A correlation coefficient filter was previously designed to minimize peak hopping artifacts. For large strains, however, the correlation coefficient filter must follow the strain distribution to remove peak hopping effectively. This processing usually means interpolation and high computational load. To reduce the computational burden, a narrow band approximation using phase rotation is developed in this paper to facilitate correlation coefficient filtering. Correlation coefficients are first phase rotated to increase coherence, then filtered. Rotated phase angles are determined by the local strain and spatial position. This form of correlation coefficient filtering enhances true correlation coefficient peaks in large strain applications if decorrelation due to deformation does not completely destroy the coherence among neighboring correlation coefficients. The assumed strain used in the filter can also deviate from the true strain and still be effective. Further improvement in displacement estimation can be expected by combining correlation coefficient filtering with a new Viterbi-based displacement estimator.
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Affiliation(s)
- Lingyun Huang
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
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66
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Olafsson R, Witte RS, Jia C, Huang SW, Kim K, O'Donnell M. Cardiac activation mapping using ultrasound current source density imaging (UCSDI). IEEE Trans Ultrason Ferroelectr Freq Control 2009; 56:565-74. [PMID: 19411215 PMCID: PMC2823813 DOI: 10.1109/tuffc.2009.1073] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We describe the first mapping of biological current in a live heart using ultrasound current source density imaging (UCSDI). Ablation procedures that treat severe heart arrhythmias require detailed maps of the cardiac activation wave. The conventional procedure is time-consuming and limited by its poor spatial resolution (5-10 mm). UCSDI can potentially improve on existing mapping procedures. It is based on a pressure-induced change in resistivity known as the acousto-electric (AE) effect, which is spatially confined to the ultrasound focus. Data from 2 experiments are presented. A 540 kHz ultrasonic transducer (f/# = 1, focal length = 90 mm, pulse repetition frequency = 1600 Hz) was scanned over an isolated rabbit heart perfused with an excitation-contraction decoupler to reduce motion significantly while retaining electric function. Tungsten electrodes inserted in the left ventricle recorded simultaneously the AE signal and the low-frequency electrocardiogram (ECG). UCSDI displayed spatial and temporal patterns consistent with the spreading activation wave. The propagation velocity estimated from UCSDI was 0.25 +/- 0.05 mm/ms, comparable to the values obtained with the ECG signals. The maximum AE signal-to-noise ratio after filtering was 18 dB, with an equivalent detection threshold of 0.1 mA/ cm(2). This study demonstrates that UCSDI is a potentially powerful technique for mapping current flow and biopotentials in the heart.
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Affiliation(s)
- Ragnar Olafsson
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, USA
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67
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Abstract
We currently present a design concept for a photoacoustic imaging endoscope as well as some preliminary experimental results. The device is based on the generation of acoustic waves in tissue by short laser pulses and the sensing of these waves with a thin, optical Fabry-Pérot etalon. The entire device is designed to be mounted on the tip of a needle to deliver high-resolution photoacoustic imaging for minimally-invasive clinical applications such as diagnosing kidney disease and guiding laparoscopic surgery.
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Affiliation(s)
- C Sheaff
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455 USA
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Abstract
Legionella is a bacterium that is ubiquitous in natural and artificial aquatic environments. Some species of Legionella are recognized as opportunistic potential human pathogens. We investigated the distribution of Legionella at seventeen WWTPs throughout Taiwan. Legionella were detected in 10 of the 17 WWTPs (58.8%) and 25 of 41 samples (61.0%). In the integrated, hospital, industrial and domestic wastewater systems were 13/18 (72.2%), 7/12 (58.3%), 2/7 (28.6%) and 3/4 (75.0%) of the samples were positive for Legionella, respectively. The most frequently encountered species were L. donaldsonii and uncultured L. spp., which were both found in 10 samples (24.4% of all samples), then followed by L. lytica (4.9%) and L. pneumophila (4.9%). L. anisa was detected in one sample (2.4%). The results of this survey confirm that Legionella are ubiquitous in WWTPs in Taiwan. Therefore, long-term investigations should be conducted to evaluate the overall occurrence of Legionella in WWTPs in Taiwan.
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Affiliation(s)
- S W Huang
- Department of Earth and Environmental Sciences, National Chung Cheng University, Minhsiung Township, Chiayi County, Chinese Taiwan
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Huang SW, Li Q, Zhu SY, Li L, Xiong F, Jia YK, Xu XM. SYBR Green-based real-time PCR assay for detection of VKORC1 and CYP2C9 polymorphisms that modulate warfarin dose requirement. Clin Chem Lab Med 2009; 47:26-31. [PMID: 19117406 DOI: 10.1515/cclm.2009.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Sheng-Wen Huang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, PR China
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70
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Hou Y, Ashkenazi S, Huang SW, O'Donnell M. An integrated optoacoustic transducer combining etalon and black PDMS structures. IEEE Trans Ultrason Ferroelectr Freq Control 2008; 55:2719-25. [PMID: 19126497 PMCID: PMC2771400 DOI: 10.1109/tuffc.2008.988] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An integrated optoacoustic transducer combining etalon and black polydimethylsiloxane (PDMS) structures has been designed and developed. The device consists of an 11-μm-thick black PDMS film confined to a 2-mm-diameter circular region acting as an optoacoustic transmitter, surrounded by a 5.9-μm Fabry-Perot polymer etalon structure serving as an optoacoustic detector array. A pulsed laser is focused onto a 30-μm spot on the black PDMS film, defining the transmit element, while a CW laser probes a 20-μm spot on the etalon for ultrasound detection. Pulse-echo signals display center frequencies of above 30 MHz with bandwidths of at least 40 MHz. A theta-array is formed for 3-D ultrasound imaging by mechanically scanning the generation laser along a 1-D array and the detection laser around an annular array. Preliminary images with 3 metal wires as imaging targets are presented. Characterization of the device’s acoustical properties, as well as preliminary imaging results, suggest that all-optical ultrasound transducers are potential alternatives to piezoelectric techniques for high-frequency 2-D arrays enabling 3-D high-resolution ultrasound imaging.
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71
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Wang HC, Huang SW, Wang SW, Tsai HP, Kiang D, Wang SM, Liu CC, Su IJ, Wang JR. Co-circulating genetically divergent A2 human metapneumovirus strains among children in southern Taiwan. Arch Virol 2008; 153:2207-13. [PMID: 19002556 PMCID: PMC7087237 DOI: 10.1007/s00705-008-0242-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 10/08/2008] [Indexed: 11/27/2022]
Abstract
An outbreak of human metapneumovirus (hMPV) among children in southern Taiwan in 2004 prompted the investigation of the molecular epidemiology of hMPV from September 2003 to August 2005. Respiratory specimens that were culture negative for a panel of respiratory viruses were examined for the presence of hMPV by RT-PCR. The results indicated that 59 out of 546 (10.8%) children were hMPV-positive. The majority of these hMPV-positive children were less than 2 years old (59.4%), females (61%), and inpatients (67.8%). Infections occurred throughout the year, but peaked during the spring and/or summer months. Sequence analysis of the fusion gene from the isolates revealed two phylogenetic groups with five possible lineages (A1, A2a/A2b, B1, and B2). Among these co-circulating strains, A2 strains were most frequently observed and demonstrated the greatest divergence. Deduced amino acid sequence analysis identified several variant amino acids specific to the A2 lineage. Lineage-specific amino acid substitutions were noted at aa233, aa286, aa312, aa348, and aa296. This study indicated that genetically divergent strains of hMPV which caused respiratory disease and hospitalization were circulating among children in Taiwan.
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Affiliation(s)
- Hsuan-Chen Wang
- Division of Clinical Research, National Health Research Institutes, No. 137, Shengli Rd., Tainan, Taiwan
| | - Sheng-Wen Huang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, No. 1 University Road, Tainan, 70101 Taiwan
| | - Shainn-Wei Wang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, No. 1 University Road, Tainan, Taiwan
| | - Huey-Pin Tsai
- Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan
| | - David Kiang
- Viral and Rickettsial Disease Laboratories, California Department of Public Health, Richmond, CA USA
| | - Shih-Min Wang
- Department of Emergency Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Ching-Chuan Liu
- Department of Pediatrics, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Ih-Jen Su
- Division of Clinical Research, National Health Research Institutes, No. 137, Shengli Rd., Tainan, Taiwan
| | - Jen-Ren Wang
- Division of Clinical Research, National Health Research Institutes, No. 137, Shengli Rd., Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, No. 1 University Road, Tainan, 70101 Taiwan
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, No. 1 University Road, Tainan, 70101 Taiwan
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72
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Huang SW, Rubin JM, Xie H, Witte RS, Jia C, Olafsson R, O'Donnell M. Analysis of correlation coefficient filtering in elasticity imaging. IEEE Trans Ultrason Ferroelectr Freq Control 2008; 55:2426-41. [PMID: 19049922 DOI: 10.1109/tuffc.950] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Correlation-based speckle tracking methods are commonly used in elasticity imaging to estimate displacements. In the presence of local strain, a larger window size results in larger displacement error. To reduce tracking error, we proposed a short correlation window followed by a correlation coefficient filter. Although simulation and experimental results demonstrated the efficacy of the method, it was not clear why correlation coefficient filtering reduces tracking error since tracking error increases if normalization before filtering is not applied. In this paper, we analyzed tracking errors by estimating phase variances of the cross-correlation function and the correlation coefficient at the true time lag based on statistical properties of these functions' real and imaginary parts. The role of normalization is clarified by identifying the effect of the cross-correlation function's amplitude fluctuation on the function's imaginary part. Furthermore, we present analytic forms for predicting axial displacement error as a function of strain, system parameters (signal-to-noise ratio, center frequency, and signal and noise bandwidths), and tracking parameters (window and filter sizes) for cases with and without normalization before filtering. Simulation results correspond to theory well for both noise-free cases and general cases with an empirical correction term included for strains up to 4%.
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Affiliation(s)
- Sheng-Wen Huang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
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73
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Abstract
Thin polymer etalons are demonstrated as high-frequency ultrasound sensors for three-dimensional (3-D) high-resolution photoacoustic imaging. The etalon, a Fabry-Perot optical resonator, consists of a thin polymer slab sandwiched between two gold layers. It is probed with a scanning continuous-wave (CW) laser for ultrasound array detection. Detection bandwidth of a 20-microm-diam array element exceeds 50 MHz, and the ultrasound sensitivity is comparable to polyvinylidene fluoride (PVDF) equivalents of similar size. In a typical photoacoustic imaging setup, a pulsed laser beam illuminates the imaging target, where optical energy is absorbed and acoustic waves are generated through the thermoelastic effect. An ultrasound detection array is formed by scanning the probing laser beam on the etalon surface in either a 1-D or a 2-D configuration, which produces 2-D or 3-D images, respectively. Axial and lateral resolutions have been demonstrated to be better than 20 microm. Detailed characterizations of the optical and acoustical properties of the etalon, as well as photoacoustic imaging results, suggest that thin polymer etalon arrays can be used as ultrasound detectors for 3-D high-resolution photoacoustic imaging applications.
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Affiliation(s)
- Yang Hou
- University of Michigan, Department of Electrical Engineering and Computer Science, 1107 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109, USA.
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74
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Yang HC, Chang CH, Huang SW, Chou YH, Li PC. Correlations among acoustic, texture and morphological features for breast ultrasound CAD. Ultrason Imaging 2008; 30:228-236. [PMID: 19507676 DOI: 10.1177/016173460803000404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Acoustic, textural and morphological features of the breast in ultrasound imaging were extracted for computer-aided diagnosis. In addition, correlations among different categories of features were analyzed. Clinical data from 14 patients (7 malignant and 7 benign samples) were acquired. A custom-made experimental apparatus was used for simultaneous data acquisition of B-mode ultrasound and limited-angle tomography images. Textural features were extracted from B-mode images, including five parameters derived from the gray-level concurrence matrix and five parameters derived from a nonseparable wavelet transform. Morphological features were also extracted from B-mode images, including the depth-to-width ratio and normalized radial gradient. Acoustic features were estimated using limited-angle tomography, including the sound velocity and attenuation coefficient. Generally, the correlation coefficients for features within the textural feature group were relatively high (0.48-0.79), whereas those between different feature categories were relatively low (0.17-0.40). This suggests that combining different sets of features would improve the computer-aided diagnosis of breast cancer.
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Affiliation(s)
- Hsin-Chia Yang
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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75
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Huang SW, Hou Y, Ashkenazi S, O'Donnell M. High-resolution ultrasonic imaging using an etalon detector array. Appl Phys Lett 2008; 93:113501. [PMID: 19529842 PMCID: PMC2682750 DOI: 10.1063/1.2982584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Accepted: 08/26/2008] [Indexed: 05/10/2023]
Abstract
A photoacoustic imaging system was built and tested to demonstrate the feasibility of high-resolution low-noise ultrasonic imaging based on parallel detection using polymer etalons. Its capability of detecting ultrasound at different elements simultaneously in the optical end was verified by imaging three 49 mum beads. An average noise-equivalent pressure of 3.6 kPa over 50 MHz for 50 mum diameter detection elements in a two-dimensional array with a diameter of 1.35 mm and a detection bandwidth of 75 MHz at -3 dB was measured. These results demonstrate the potential of polymer etalons for high-frame-rate high-resolution three-dimensional photoacoustic and ultrasound pulse-echo imaging.
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76
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Abstract
Surgery to correct severe heart arrhythmias usually requires detailed maps of the cardiac activation wave prior to ablation. The pinpoint electrical mapping procedure is laborious and limited by its spatial resolution (5-10 mm). We propose ultrasound current source density imaging (UCSDI), a direct 3-D imaging technique that potentially facilitates existing mapping procedures with superior spatial resolution. The technique is based on a pressure-induced change in resistivity known as the acoustoelectric (AE) effect, which is spatially confined to the ultrasound focus. AE-modulated voltage recordings are used to map and reconstruct current densities. In this preliminary study, we tested UCSDI under controlled conditions and compared it with conventional electrical mapping techniques. A 2-D dipole field was produced by a pair of electrodes in a bath of 0.9% NaCl solution. Boundary electrodes detected the AE signal while a 7.5-MHz focused ultrasound transducer was scanned across the bath. UCSDI located the current source and sink to within 1 mm of their actual positions. A future UCSDI system potentially provides real-time 3-D images of the cardiac activation wave coregistered with anatomical ultrasound and would greatly facilitate corrective procedures for heart abnormalities.
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Affiliation(s)
- Ragnar Olafsson
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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77
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Huang SW, Huang DJ, Okamoto J, Mou CY, Wu WB, Yeh KW, Chen CL, Wu MK, Hsu HC, Chou FC, Chen CT. Magnetic ground state and transition of a quantum multiferroic LiCu2O2. Phys Rev Lett 2008; 101:077205. [PMID: 18764576 DOI: 10.1103/physrevlett.101.077205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Indexed: 05/26/2023]
Abstract
Based on resonant soft x-ray magnetic scattering, we report that LiCu2O2 exhibits a large interchain coupling which suppresses quantum fluctuations along spin chains, and a quasi-2D short-range magnetic order prevails at temperatures above the magnetic transition. These observations unravel the fact that the ground state of LiCu2O2 possesses long-range 2D-like incommensurate magnetic order rather than being a gapped spin liquid as expected from the nature of quantum spin-1/2 chains. In addition, the spin coupling along the c axis is found to be essential for inducing electric polarization.
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Affiliation(s)
- S W Huang
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
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78
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Hou Y, Kim JS, Huang SW, Ashkenazi S, Guo LJ, O'Donnell M. Characterization of a broadband all-optical ultrasound transducer-from optical and acoustical properties to imaging. IEEE Trans Ultrason Ferroelectr Freq Control 2008; 55:1867-77. [PMID: 18986929 PMCID: PMC2760086 DOI: 10.1109/tuffc.2008.870] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A broadband all-optical ultrasound transducer has been designed, fabricated, and evaluated for high- frequency ultrasound imaging. The device consists of a 2-D gold nanostructure imprinted on top of a glass substrate, followed by a 3 microm PDMS layer and a 30 nm gold layer. A laser pulse at the resonance wavelength of the gold nanostructure is focused onto the surface for ultrasound generation, while the gold nanostructure, together with the 30 nm thick gold layer and the PDMS layer in between, forms an etalon for ultrasound detection, which uses a CW laser at a wavelength far from resonance as the probing beam. The center frequency of a pulse-echo signal recorded in the far field of the transducer is 40 MHz with -6 dB bandwidth of 57 MHz. The signal to noise ratio (SNR) from a 70 microm diameter transmit element combined with a 20 microm diameter receive element probing a near perfect reflector positioned 1.5 mm from the transducer surface is more than 10 dB and has the potential to be improved by at least another 40 dB. A high-frequency ultrasound array has been emulated using multiple measurements from the transducer while mechanically scanning an imaging target. Characterization of the device's optical and acoustical properties, as well as preliminary imaging results, strongly suggest that all-optical ultrasound transducers can be used to build high-frequency arrays for real-time high-resolution ultrasound imaging.
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Affiliation(s)
- Yang Hou
- Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI, USA.
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79
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Huang SW, Chen SL, Ling T, Maxwell A, O'Donnell M, Guo LJ, Ashkenazi S. Low-noise wideband ultrasound detection using polymer microring resonators. Appl Phys Lett 2008; 92:193509-1935093. [PMID: 19479044 PMCID: PMC2682739 DOI: 10.1063/1.2929379] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 04/24/2008] [Indexed: 05/04/2023]
Abstract
Polymer microring resonators for low-noise, wideband ultrasound detection are presented. Using a nanoimprinting technique, we fabricated polymer microring resonators with a quality factor of 6000 resulting in high sensitivity to ultrasound. A noise-equivalent pressure of 0.23 kPa over 1-75 MHz and a detection bandwidth of over 90 MHz at -3 dB were measured. These results demonstrate the potential of polymer microring resonators for high-frequency ultrasound and photoacoustic imaging. For a typical photoacoustic imaging test case, the high sensitivity demonstrated in these devices would increase imaging depth by a factor of 3 compared to state-of-the-art polyvinylidene fluoride detectors.
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80
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Li Q, Li LY, Huang SW, Li L, Chen XW, Zhou WJ, Xu XM. Rapid genotyping of known mutations and polymorphisms in beta-globin gene based on the DHPLC profile patterns of homoduplexes and heteroduplexes. Clin Biochem 2008; 41:681-7. [PMID: 18339318 DOI: 10.1016/j.clinbiochem.2008.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2007] [Revised: 12/24/2007] [Accepted: 02/05/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND Beta-thalassemia represents a great heterogeneity as over 200 mutations have been identified for the beta-globin gene responsible for this disease. A rapid genotyping test with high accuracy, selectivity, and reproducibility suitable for the determination of known mutations is needed for prenatal screening and post-natal diagnosis of this disease in clinical setting. DESIGN AND METHODS We have performed the validation of a DHPLC assay for direct genotyping of known causative mutations in beta-globin gene using the chromatographic pattern-based strategy under partially-denaturing conditions. RESULTS DHPLC assay was established based on the analysis of 795 DNA samples from a group of various genotypes for the 20 mutations and 8 polymorphisms in beta-globin gene then validated on 319 tests in a blind study. The results obtained with this assay were in concordance with the results obtained by DNA sequence analysis. CONCLUSION This simple method can meet the requirements of direct genotyping of known beta-thalassemia mutations and/or polymorphisms in the clinical setting for Chinese and in general as a model for other populations.
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Affiliation(s)
- Qiang Li
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, PR China
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81
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Huang SC, Hsu YW, Wang HC, Huang SW, Kiang D, Tsai HP, Wang SM, Liu CC, Lin KH, Su IJ, Wang JR. Appearance of intratypic recombination of enterovirus 71 in Taiwan from 2002 to 2005. Virus Res 2008; 131:250-9. [DOI: 10.1016/j.virusres.2007.10.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 10/03/2007] [Accepted: 10/08/2007] [Indexed: 10/22/2022]
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82
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Maxwell A, Huang SW, Ling T, Kim JS, Ashkenazi S, Guo LJ. Polymer Microring Resonators for High-Frequency Ultrasound Detection and Imaging. IEEE J Sel Top Quantum Electron 2008; 14:191-197. [PMID: 20700482 PMCID: PMC2917845 DOI: 10.1109/jstqe.2007.914047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Polymer microring resonators fabricated by nanoimprinting are presented as a means of ultrasound detection. Acoustic waves impinging on a ring-shaped optical resonator cause strain in the ring dimensions, modulating optical output. Basic acoustic and optical characteristics of the microring sensor are presented. Measurements at several frequencies show a high sensitivity and low noise-equivalent pressure. The angular response is determined by sensing the optoacoustic excitation of a 49 μm polyester microsphere and shows wide-angle sensitivity. A 1-D array consisting of 4 microrings is demonstrated using wavelength multiplexing for addressing each element. The high sensitivity, bandwidth, and angular response make it a potentially useful sensor platform for many applications including high-frequency ultrasonic and photoacoustic imaging.
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Affiliation(s)
- Adam Maxwell
- A. Maxwell, T. Ling, J.-S. Kim and L. J. Guo are with the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor, MI 48109 USA ( )
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83
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Witte RS, Hall T, Olafsson R, Huang SW, O'Donnell M. Inexpensive Acoustoelectric Hydrophone For Mapping High Intensity Ultrasonic Fields. J Appl Phys 2008; 104:54701. [PMID: 19079752 PMCID: PMC2600872 DOI: 10.1063/1.2974622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We describe an inexpensive alternative to conventional hydrophones for measuring ultrasonic fields. The hydrophone, composed of common laboratory supplies, depends on the acoustoelectric (AE) effect, a well-known interaction between electrical current and pressure. Beam patterns of a 540 kHz annular transducer captured using a bowtie graphite hydrophone were consistent with patterns obtained using conventional, more expensive hydrophones. The AE signal was proportional to both the applied bias current (1.83 µV/mA) and pressure (13.3 µV/MPa) with sensitivity better than 50 kPa. Disposable AE hydrophones may be an attractive alternative for clinical applications that require close monitoring of high intensity acoustic fields.
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84
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Han YH, Zhang ZH, Liu JH, Lu JY, Huang SW, Jin WW. Distribution of the tandem repeat sequences and karyotyping in cucumber ( Cucumis sativus L.) by fluorescence in situ hybridization. Cytogenet Genome Res 2008; 122:80-8. [PMID: 18931490 DOI: 10.1159/000151320] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2008] [Indexed: 11/19/2022] Open
Affiliation(s)
- Y H Han
- National Maize Improvement Center of China, Key Laboratory of Crop Genetic Improvement and Genome Ministry of Agriculture, China Agricultural University, Beijing, China
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85
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Chang CH, Huang SW, Yang HC, Chou YH, Li PC. Reconstruction of ultrasonic sound velocity and attenuation coefficient using linear arrays: clinical assessment. Ultrasound Med Biol 2007; 33:1681-7. [PMID: 17629607 DOI: 10.1016/j.ultrasmedbio.2007.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 05/11/2007] [Accepted: 05/16/2007] [Indexed: 05/14/2023]
Abstract
The aim of this study was to determine the efficacy of using sound velocity and tissue attenuation to clinically discriminate breast cancer from healthy tissues. The methods for reconstructing the sound-velocity and attenuation-coefficient distributions were previously proposed and tested on tissue-mimicking phantoms. The methods require only raw channel data acquired by a linear transducer array and can therefore be implemented on existing clinical systems. In this paper, these methods are tested on clinical data. A total of 19 biopsy-proven cases, consisting of five carcinomas (CAs), seven fibroadenomas (FAs), six adipose tissue (fat) and one oil cyst, were evaluated. A single imaging setup consisting of a 5-MHz, 128-channel linear array was used to simultaneously obtain B-mode image data, time-of-flight data and attenuation data. The sound velocity and attenuation coefficient can be reconstructed inside and outside a region of interest manually selected in the B-mode image. To reduce distortion caused by tissue inhomogeneities, an optimal filter derived from pulse-echo data-with water replacing the breast tissue-is applied. We found that the sound velocities in CA, FA and fat tissues relative to those in the surrounding tissues were 49.8 +/- 35.2, 2.6 +/- 27.3 and -25.1 +/- 44.9 m/s (mean +/- SD), respectively, whereas the relative attenuation coefficients were 0.21 +/- 0.58, 0.27 +/- 0.62 and -0.02 +/- 0.59 dB/cm/MHz. These results indicate that CA can be discriminated from FA and fat by choosing an appropriate threshold for the relative sound velocity (i.e., 18.5 m/s). However, the large variations in the attenuation within the same type of tissue make simple thresholding ineffective. Nevertheless, the method described in this paper has the potential to reduce negative biopsies and to improve the accuracy of breast cancer detection in clinics.
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Affiliation(s)
- Chen-Han Chang
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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86
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Abstract
A quantitative flow measurement method that utilizes a sequence of photoacoustic images is described. The method is based on the use of gold nanorods as a contrast agent for photoacoustic imaging. The peak optical absorption wavelength of a gold nanorod depends on its aspect ratio, which can be altered by laser irradiation (we establish a wash-in flow estimation method of this process). The concentration of nanorods with a particular aspect ratio inside a region of interest is affected by both laser-induced shape changes and replenishment of nanorods at a rate determined by the flow velocity. In this study, the concentration is monitored using a custom-designed, high-frame-rate photoacoustic imaging system. This imaging system consists of fiber bundles for wide area laser irradiation, a laser ultrasonic transducer array, and an ultrasound front-end subsystem that allows acoustic data to be acquired simultaneously from 64 transducer elements. Currently, the frame rate of this system is limited by the pulse-repetition frequency of the laser (i.e., 15 Hz). With this system, experimental results from a chicken breast tissue show that flow velocities from 0.125 to 2 mms can be measured with an average error of 31.3%.
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Affiliation(s)
- Chao-Kang Liao
- National Taiwan University, Department of Electrical Engineering, Taipei 106, Taiwan
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87
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Huang SW, Kim K, Witte RS, Olafsson R, O'Donnell M. Inducing and imaging thermal strain using a single ultrasound linear array. IEEE Trans Ultrason Ferroelectr Freq Control 2007; 54:1718-1720. [PMID: 17941376 DOI: 10.1109/tuffc.2007.454] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
For the first time, the feasibility of inducing and imaging thermal strain using an ultrasound imaging array is demonstrated. A commercial ultrasound scanner was used to heat and image a gelatin phantom with a cylindrical rubber inclusion. The inclusion was successfully characterized as an oil-bearing material using thermal strain imaging.
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88
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Kim G, Huang SW, Day KC, O'Donnell M, Agayan RR, Day MA, Kopelman R, Ashkenazi S. Indocyanine-green-embedded PEBBLEs as a contrast agent for photoacoustic imaging. J Biomed Opt 2007; 12:044020. [PMID: 17867824 DOI: 10.1117/1.2771530] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nanoparticles 100 nm in diameter containing indocyanine green (ICG) have been developed as a contrast agent for photoacoustic (PA) imaging based on (photonic explorers for biomedical use by biologically localized embedding PEBBLE) technology using organically modified silicate (ormosil) as a matrix. ICG is an FDA-approved dye with strong optical absorption in the near-infrared (NIR) region, where light can penetrate deepest into biological tissue. A photoacoustic imaging system was used to study image contrast as a function of PEBBLE concentration in phantom objects. ICG-embedded ormosil PEBBLEs showed improved stability in aqueous solution compared with free ICG dye. The particles were conjugated with HER-2 antibody for breast cancer and prostate cancer cell targeting. Initial in vitro characterization shows high contrast and high efficiency for binding to prostate cancer cells. ICG can also be used as a photosensitizer (generating toxic oxygen by illumination) for photodynamic therapy. We have measured the photosensitization capability of ICG-embedded ormosil nanoparticles. This feature can be utilized to combine detection and therapeutic functions in a single agent.
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Affiliation(s)
- Gwangseong Kim
- University of Michigan, Department of Chemistry, Ann Arbor, Michigan 48109, USA
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89
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Wei CW, Huang SW, Wang CRC, Li PC. Photoacoustic flow measurements based on wash-in analysis of gold nanorods. IEEE Trans Ultrason Ferroelectr Freq Control 2007; 54:1131-41. [PMID: 17571812 DOI: 10.1109/tuffc.2007.367] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this study, photoacoustic flow measurement methods based on wash-in analysis are presented. These methods use the rod-to-sphere shape transformations of gold nanorods induced by pulsed-laser irradiation. Due to the shape dependence of the optical absorption of the gold nanorods, these shape transitions are associated with a change in the peak optical absorption wavelength. Pulsed-laser irradiation at the wavelength corresponding to the peak optical absorption of the original gold nanorods allows the particles that undergo shape changes to be viewed as "being destructed" by the laser irradiation at that wavelength, hence, flow information can be derived from the change in ultrasound intensity that is directly related to the wash-in rate of the gold nanorods and the laser intensity. Two flow estimation methods based on the wash-in analysis are described. The first method first applies high-energy laser pulses that induce shape changes in all the nanorods. A series of low-energy pulses then are applied to monitor the acoustic signal change as new nanorods flow into the region of interest. The second method uses single-energy laser pulses such that the "destruction" and "detection" are performed simultaneously. The simulation results show that it is valid to fit the time-intensity curves by exponential models. To demonstrate the validity of the proposed methods, an Nd:YAG pulsed laser operating at 1064 nm was used for optical irradiation, and a 1-MHz ultrasonic transducer was used for acoustic detection. Gold nanorods with a peak optical absorption at 1018 nm and a concentration of 0.26 nM were used to estimate flow velocities ranging from 0.35 to 2.83 mm/s. The linear regression results show that the correlation coefficients between the measured velocities and the true values are close to unity (> or = 0.94), thus demonstrating the feasibility of the proposed photoacoustic techniques for relative flow estimation.
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Affiliation(s)
- Chen-Wei Wei
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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90
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Huang SW, Li PC. Binary code design for high-frequency ultrasound. IEEE Trans Ultrason Ferroelectr Freq Control 2007; 54:947-56. [PMID: 17523559 DOI: 10.1109/tuffc.2007.340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This paper proposes an approach to designing binary codes suitable for high-frequency applications of coded excitation in medical ultrasound. For a high-frequency ultrasound system, transmitting well-designed binary codes with a low sampling ratio (i.e., the bit rate divided by the transducer center frequency) is a practical way to improve the signal-to-noise ratio (SNR) because the challenge of implementing arbitrary-waveform generators for transmitting nonbinary codes increases with the frequency and the switching speed of square-wave pulsers are limited. One conventional approach designs codes using a base sequence that modulates wideband sequences up to the transducer passband. Because a major portion of codes is excluded as a candidate, codes designed using this approach typically need long compression filters for restoring the axial resolution, and they do not improve the SNR efficiently. In contrast, the approach proposed here searches all the codes that match the transducer passband; hence, the resultant codes exhibit better performance. The technique was tested using a bit rate of 50 MHz and a sampling ratio of 2. For a transducer with an ideal Gaussian frequency response with a center frequency of 25 MHz and a -6 dB bandwidth of 15 MHz, the SNR for the same side-lobe extent was 1 to 6 dB higher for the codes designed using the proposed approach compared with those designed using the conventional approach. When a real transducer response with a center frequency of 26.4 MHz and a one-way -6 dB bandwidth of 20.7 MHz was considered, the codes designed using the proposed approach were superior by 0.5 to 5 dB. Therefore, our approach is better than the conventional approach for designing binary codes for high-frequency ultrasound, with the results indicating that the moderate bit rate of 50 MHz will suffice when the ultrasonic center frequency is 25 MHz.
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Affiliation(s)
- Sheng-Wen Huang
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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91
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Chao CY, Ashkenazi S, Huang SW, O'Donnell M, Guo LJ. High-frequency ultrasound sensors using polymer microring resonators. IEEE Trans Ultrason Ferroelectr Freq Control 2007; 54:957-65. [PMID: 17523560 DOI: 10.1109/tuffc.2007.341] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Polymer microring resonators are demonstrated as high-frequency, ultrasound detectors. An optical microring resonator consists of a ring waveguide closely coupled to a straight bus waveguide, serving as light input and output. Acoustic waves irradiating the ring induce strain, deforming the waveguide dimensions and changing the refractive index of the waveguide via the elasto-optic effect. These effects modify the effective refractive index of the guided mode inside the waveguide. The sharp wavelength dependence of the microring resonance can enhance the optical response to acoustic strain. Such polymer microring resonators are experimentally demonstrated in detecting broadband ultrasound pulses from a 50 MHz transducer. Measured frequency response shows that these devices have potential in high-frequency, ultrasound detection. Design guidelines for polymer microring resonators forming an ultrasound detector array are discussed.
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Affiliation(s)
- Chung-Yen Chao
- Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor, MI 48109, USA
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92
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Hou Y, Ashkenazi S, Huang SW, O'Donnell M. Improvements in optical generation of high-frequency ultrasound. IEEE Trans Ultrason Ferroelectr Freq Control 2007; 54:682-6. [PMID: 17375838 DOI: 10.1109/tuffc.2007.292] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The thermoelastic effect in a black polydimethylsiloxane (PDMS) film is used to produce high-frequency, high-intensity ultrasound for applications in water and soft tissue. We show that the optoacoustic transduction efficiency is improved by about 10 dB by decreasing the thickness of the black PDMS film from 25 microm to 11 microm. The center frequency of the generated ultrasound is 60 MHz, with a -6 dB bandwidth of 80%. When a 5 ns laser pulse with energy of 50 microJ is delivered to a spot size of 25 microm, the acoustic pressure 10 mm away from the film surface is about 800 kPa. Furthermore, we demonstrate that the center frequency and bandwidth of the generated ultrasound is mainly determined by the temporal profile of the input optical pulse, and it has the potential to be easily improved to above 100 MHz.
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93
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Juan CC, Chang CL, Chuang TY, Huang SW, Kwok CF, Ho LT. Insulin sensitivity and resistin expression in nitric oxide-deficient rats. Diabetologia 2006; 49:3017-26. [PMID: 17063326 DOI: 10.1007/s00125-006-0403-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Accepted: 07/03/2006] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to investigate changes in insulin sensitivity and expression of the gene encoding resistin (Retn) in adipocytes from long-term nitric oxide (NO)-deficient rats. METHODS Male Sprague-Dawley rats received [Formula: see text]-nitro-L: -arginine methyl ester (L-NAME 0.5 mg/ml) in their drinking water for 4 weeks, while control rats received plain drinking water. During the experimental period, changes in plasma glucose, insulin and C-peptide levels were measured. After administration of L-NAME for 4 weeks, insulin sensitivity was evaluated in vivo and in vitro. An insulin binding assay was also performed to determine the number and binding affinity of insulin receptors in adipocytes. Adipocyte Retn mRNA levels were examined using northern blotting. RESULTS Successful induction of NO deficiency was demonstrated by an increase in systemic blood pressure. No difference in plasma glucose levels was found between the two groups. Compared with the control rats, plasma insulin and C-peptide levels were significantly decreased in the NO-deficient rats, and insulin sensitivity was significantly increased. Insulin-stimulated glucose uptake and insulin binding capacity, but not binding affinity, were significantly increased in adipocytes isolated from NO-deficient rats. In addition, adipocyte Retn mRNA levels, but not plasma resistin levels, were significantly decreased in NO-deficient rats, and the Retn mRNA levels were negatively correlated with insulin sensitivity. CONCLUSIONS/INTERPRETATION Insulin sensitivity was increased in NO-deficient rats and this was associated with insulin binding capacity and downregulated Retn expression. These findings suggest that NO plays a regulatory role in metabolism. Dysregulation of NO production may result in the development of metabolic disorders.
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Affiliation(s)
- C C Juan
- Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
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94
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Tsai HP, Wang HC, Kiang D, Huang SW, Kuo PH, Liu CC, Su IJ, Wang JR. Increasing appearance of reassortant influenza B virus in Taiwan from 2002 to 2005. J Clin Microbiol 2006; 44:2705-13. [PMID: 16891481 PMCID: PMC1594622 DOI: 10.1128/jcm.02694-05] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic and antigenic analyses of influenza B virus field strains isolated in Taiwan from 1998 to 2005 were performed. To investigate the molecular evolution of influenza B viruses, sequence analysis of the hemagglutinin (HA1 subunit) and neuraminidase genes was performed. All influenza B viruses isolated between 1998 and 2000 belonged to the B/Yamagata/16/88 lineage. The B/Victoria/2/87 lineage, which was cocirculating with the Yamagata lineage, was identified in Taiwan in March 2001. Concurrently, there was an increasing prevalence of this lineage in many parts of the world, including North America and Europe, during the 2001-2002 season. Since 2002, genetic reassortants of influenza B virus with the Victoria lineage of hemagglutinin and the Yamagata lineage of neuraminidase have been found at a rate of 46%. Therefore, in 2002, at least three sublineages of influenza B virus strains, the B/Shanghai/361/2002-like strain (Yamagata lineage), the B/Hong Kong/330/01-like strain (Victoria lineage), and the B/Hong Kong/1351/02-like strain (B reassortant lineage), were identified in Taiwan. The results showed that genetically distinct lineages can cocirculate in the population and that the reassortment among these strains plays a role in generating the genetic diversity of influenza B viruses. Interestingly, from January to April 2005, B reassortant viruses became dominant (73%) in Taiwan, which indicated that a mismatch had occurred between the influenza B vaccine strain recommended for the 2004-2005 season in the Northern hemisphere by the World Health Organization and the epidemic strain.
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Affiliation(s)
- Huey-Pin Tsai
- Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan
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95
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Abstract
Pulse-inversion (PI) fundamental imaging exhibits significantly better contrast detection than linear and second-harmonic imaging. PI fundamental imaging involves two firings with inverted waveforms. When the returning echoes from the two firings are summed, the residual signal related to tissue is limited to even-order harmonics, whereas for microbubbles, the fundamental signal is not completely canceled due to the echo under compression differing from that under rarefaction. The efficacy of PI fundamental imaging has been reported previously. In this study, we investigated the performance of PI fundamental imaging using both simulations and in vitro experiments with various transmit waveforms, including coded excitation and asymmetrical waveforms (i.e., asymmetrical between compression and rarefaction). For coded excitation, a longer waveform was found to increase the similarity in the responses to positive and negative pulses, thus lowering the contrast between microbubbles and tissue. In addition, imperfect pulse compression also decreases the contrast because it increases the residue fundamental signal emanating from tissue. Using asymmetrical waveforms noticeably increased the residual microbubble signal in the fundamental band but the nonzero DC component that is inherent in such waveforms also increases the tissue fundamental signal. The combination of these two effects decreases the contrast. From these results, it is concluded that the use of coded excitation is undesirable in PI fundamental imaging and that the waveforms should contain no DC component. Furthermore, the transmit waveform needs to be appropriately windowed in order to reduce spectral leakage. Therefore, a Gaussian pulse with the pulse length determined by the signal-to-noise ratio of the imaging system is generally optimal for PI fundamental imaging.
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Affiliation(s)
- Pai-Chi Li
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
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96
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Huang SW, Li PC. Arbitrary waveform coded excitation using bipolar square wave pulsers in medical ultrasound. IEEE Trans Ultrason Ferroelectr Freq Control 2006; 53:106-16. [PMID: 16471437 DOI: 10.1109/tuffc.2006.1588396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This paper presents a new coded excitation scheme that efficiently synthesizes codes for arbitrary waveforms using a bipolar square wave pulser. In a coded excitation system, pulse compression is performed to restore the axial resolution. In order to maintain low range sidelobes, the system needs to transmit signals that have smooth spectra. However, such a transmitter requires the generation of arbitrary waveforms and, therefore, is more expensive. In other words, a trade-off is necessary between the compression performance and the transmitter cost. Here we propose a method that preserves the low-cost advantage of a bipolar pulser while achieving approximately the same compression performance as an arbitrary waveform generator. The key idea of the proposed method is the conversion of a nonbinary code (i.e., requiring an arbitrary waveform generator) with good compression performance into a binary code (i.e., requiring only a bipolar pulser) by code translation and code tuning. The code translation is implemented by sending the nonbinary code into a virtual one-bit, sigma-delta modulator, and the code tuning involves minimizing the root-mean-square error between the resultant binary code and the original nonbinary code by sequential and iterative tuning while taking the transducer response into account. Tukey-windowed chirps are known to have good compression performance. Such chirps of different durations (16, 20, and 24 micros), all with a taper ratio of 0.15, a center frequency of 2.5 MHz, and an equivalent bandwidth of 1.5 MHz, were converted into binary Tukey-windowed chirps that were compared with pseudochirps (i.e., direct binary approximations of the original chirp) over the same spectral band. The bit rate was 40 MHz. Simulation results show that the use of binary Tukey-windowed chirps can reduce the code duration by 20.6% or the peak sidelobe level by 6 dB compared to the commonly used pseudochirps. Experimental results obtained under the same settings were in agreement with the simulations. Our results demonstrate that arbitrary waveform coded excitation can be realized using bipolar square wave pulsers for applications in medical ultrasound.
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Affiliation(s)
- Sheng-Wen Huang
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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97
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Li PC, Huang SW, Wei CW, Chiou YC, Chen CD, Wang CRC. Photoacoustic flow measurements by use of laser-induced shape transitions of gold nanorods. Opt Lett 2005; 30:3341-3. [PMID: 16389825 DOI: 10.1364/ol.30.003341] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A quantitative technique for flow measurements based on a wash-in analysis is proposed. The technique makes use of the shape dependence of the optical absorption of gold nanorods and the transitions in their shape induced by pulsed laser irradiation. The photon-induced shape transition of gold nanorods involves mainly a rod-to-sphere conversion and a shift in the peak optical absorption wavelength. The application of a series of laser pulses will induce shape changes in gold nanorods as they flow through a region of interest, with quantitative flow information being derived from the photoacoustic signals from the irradiated gold nanorods measured as a function of time. To demonstrate the feasibility of the technique, a Nd:YAG laser operating at 1064 nm was used for irradiation and a 1 MHz ultrasonic transducer was used for acoustic detection. The flow velocity ranged from 0.35 to 2.83 mm/s. Excellent agreement between the measured velocities and the actual velocities was demonstrated, with a linear regression correlation coefficient of 0.93. This study is a pioneer work on wash-in flow estimation in photoacoustic imaging.
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Affiliation(s)
- Pai-Chi Li
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
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98
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Huang SW, Li PC. Ultrasonic computed tomography reconstruction of the attenuation coefficient using a linear array. IEEE Trans Ultrason Ferroelectr Freq Control 2005; 52:2011-22. [PMID: 16422413 DOI: 10.1109/tuffc.2005.1561670] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The attenuation coefficient distribution and sound velocity distribution in the breast can be used to complement B-mode ultrasound imaging in the detection of breast cancer. This study investigated an approach for reconstructing the attenuation coefficient distribution in the breast using a linear array. The imaging setup was identical to that for conventional B-mode breast imaging, and the same setup has been used for reconstruction of sound velocity distributions in previous studies. In this study, we further developed a reconstruction method for the attenuation coefficient distribution. In particular, the proposed method incorporates the segmentation information from B-mode images and uses the sound velocity distribution to compensate for refraction effects. Experiments were conducted with a setup consisting of a 5-MHz, 128-channel linear array, a programmable digital array system, a phantom, and a computer. The constructed phantom contained materials mimicking the following breast tissues: glandular tissue, fat, cysts, high-attenuation tumors, and irregular tumors. Application of the proposed technique resulted in all the cysts and tumors (including high-attenuation and irregular tumors) being distinguished by thresholding the reconstructed attenuation coefficients. We have demonstrated that it is possible to use the same imaging setup to acquire data for B-mode image, sound velocity distribution, and attenuation coefficient distribution simultaneously. Moreover, the experimental data indicate its potential in improving the detection of breast cancer.
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Affiliation(s)
- Sheng-Wen Huang
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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99
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Lin KH, Chern GW, Yu CT, Liu TM, Pan CC, Chen GT, Chyi JI, Huang SW, Li PC, Sun CK. Optical piezoelectric transducer for nano-ultrasonics. IEEE Trans Ultrason Ferroelectr Freq Control 2005; 52:1404-14. [PMID: 16245610 DOI: 10.1109/tuffc.2005.1509800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Piezoelectric semiconductor strained layers can be treated as piezoelectric transducers to generate nanometer-wavelength and THz-frequency acoustic waves. The mechanism of nano-acoustic wave (NAW) generation in strained piezoelectric layers, induced by femtosecond optical pulses, can be modeled by a macroscopic elastic continuum theory. The optical absorption change of the strained layers modulated by NAW through quantum-confined Franz-Keldysh (QCFK) effects allows optical detection of the propagating NAW. Based on these piezoelectric-based optical principles, we have designed an optical piezoelectric transducer (OPT) to generate NAW. The optically generated NAW is then applied to one-dimensional (1-D) ultrasonic scan for thickness measurement, which is the first step toward multidimensional nano-ultrasonic imaging. By launching a NAW pulse and resolving the returned acoustic echo signal with femtosecond optical pulses, the thickness of the studied layer can be measured with <1 nm resolution. This nano-structured OPT technique will provide the key toward the realization of nano-ultrasonics, which is analogous to the typical ultrasonic techniques but in a nanometer scale.
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Affiliation(s)
- Kung-Hsuan Lin
- Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei 10617, Taiwan
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100
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Li ML, Huang SW, Ustüner K, Li PC. Adaptive imaging using an optimal receive aperture size. Ultrason Imaging 2005; 27:111-27. [PMID: 16231840 DOI: 10.1177/016173460502700205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Sidelobe contribution from off-axis targets degrades image quality in a coherent array imaging system. In ultrasound imaging, focusing errors resulting from sound-velocity inhomogeneities in human tissue--also known as phase aberrations reduce the coherence of the received signals and elevate the sidelobe level. This paper proposes an adaptive receive-aperture technique based on thresholding of the coherence factor (CF). The CF describes the coherence of the received array signals and can be used as an index of focusing quality. This paper demonstrates that thresholding of the CF allows the mainlobe-dominated signals to be distinguished from the sidelobe-dominated signals, after which the receive-aperture size at each imaging position can be optimally determined so as to enhance the mainlobe-dominated signals and suppress the sidelobe-dominated signals. Thus, image quality degradation resulting from sound-velocity inhomogeneities can be reduced. Simulations and measured ultrasound data are used to evaluate the efficacy of the proposed technique. The characteristics of the proposed technique including the effects of the signal-to-noise ratio (SNR) and the transmit focal depth, and speckle reduction are discussed. The proposed technique is also compared with the parallel adaptive receive compensation algorithm and shown to produce a better improvement in image quality.
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Affiliation(s)
- Meng-Lin Li
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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