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Author

Osama M. Mukdadi

Bio: Osama M. Mukdadi is an academic researcher from West Virginia University. The author has contributed to research in topics: Ultrasonic sensor & Dispersion (water waves). The author has an hindex of 14, co-authored 58 publications receiving 690 citations. Previous affiliations of Osama M. Mukdadi include Khalifa University & Office of Technology Transfer.


Papers
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Proceedings ArticleDOI
23 Aug 2004
TL;DR: In this paper, a novel process, incorporating atomic layer deposition (ALD) and diffusion bonding, for the fabrication of CMUTs with ultra-thin membranes is introduced, which facilitates the development of miniature capacitive micromachined ultrasonic transducers, which have great potential in biomedical imaging applications.
Abstract: Production of ultra-thin membranes facilitates the development of miniature capacitive micromachined ultrasonic transducers (CMUTs), which have great potential in biomedical imaging applications. We introduce a novel process, incorporating atomic layer deposition (ALD) and diffusion bonding, for the fabrication of CMUTs with ultra-thin membranes. First, an Al/sub 2/O/sub 3/ layer is deposited on an upper silicon wafer by ALD. Next, a gold layer is deposited on the Al/sub 2/O/sub 3/ layer and patterned to create circular cavities. Then the whole structure is transferred to a bottom wafer by diffusion bonding and the upper silicon wafer is etched away to release the Al/sub 2/O/sub 3/ membrane. Finally, another gold layer is deposited on the membrane for wiring and membrane excitation. Initial results show high quality membranes can be produced using this process with highly conformal surface qualities and extremely thin dimensions (<300 nm). Based on the dimensional characteristics created by this process, we simulate the performance of these transducers using equivalent circuit analysis. The results show that this new fabrication method provides another avenue for optimizing CMUT performance, especially in power savings, sensitivity and potentially increased reliability. Work to test the fabricated elements is currently under way.

11 citations

Proceedings ArticleDOI
15 Apr 2004
TL;DR: Results show that these systems have the potential for excellent sensitivity and decreased power requirements, and a first-order mechanical and equivalent circuit analysis along with a fabrication process to create and characterize CMUTs using ALD.
Abstract: In this paper, we examine the utility of a new method for fabricating capacitive micromachined ultrasonic transducers (CMUTs). The method is based on atomic layer deposition (ALD) technology, which uses a self-limiting binary reaction process to produce ultra-thin membranes. Advantages of ALD include precise control of dimensions including gap-width between the capacitor plates, membrane thickness and radius, lower cost due to a reduction in the number of fabrication steps, the potential to use a large variety of materials, and increased reliability due to the enhanced surface quality of the membranes. These capabilities promise fabrication of transducers with superior operating characteristics. However, no study has yet documented sensitivity and power requirements for CMUTs created using ALD. We present here a first-order mechanical and equivalent circuit analysis along with a fabrication process to create and characterize CMUTs using ALD. Results show that these systems have the potential for excellent sensitivity and decreased power requirements. Work to test the fabricated elements is currently underway.

10 citations

Journal Article
TL;DR: Results show that the rectangular wave is effective in improving the visibility of microbubbles with ultrasound backscattered efficiency significantly higher than the widely used Gaussian waveform.
Abstract: We have recently developed an ultrasound based velocimetry technique, termed echo particle image velocimetry (echo PIV). This method takes advantage of the non-linear backscatter characteristics of ultrasound contrast microbubbles when exposed to certain ultrasonic field. Preliminary in vitro, animal and clinical studies have shown significant promise of this method for measuring multiple velocity components with good temporal and spatial resolution. However, there is still difficulty in maximizing the non-linearity of bubble backscatter using conventional Gaussian-pulse excitation techniques because significant harmonic components may not be produced at modest pressure amplitudes and the higher incident pressure amplitudes required to induce non-linear behavior may cause bubble destruction. We present here a potential solution to this problem through the use of multi-frequency excitation. A rectangular pulse with multiple harmonics is used to drive the bubble. The backscatter process is studied through a modified Rayleigh-Plesset equation. Results show that the rectangular wave is effective in improving the visibility of microbubbles with ultrasound backscattered efficiency significantly higher than the widely used Gaussian waveform. Use of rectangular pulses with 4 and 2 harmonics showed no significant difference in bubble backscatter behavior, indicating that a two-frequency excitation may be sufficient to induce non-linear behavior of the microbubbles practically at modest incident pressures.

9 citations

Journal ArticleDOI
TL;DR: In this article , five designs of axial and radial functionally graded materials (FGM) implants besides the conventional implant and conical and cylindrical shapes were simulated with five different bone densities.

7 citations

Journal ArticleDOI
TL;DR: The feasibility of a high-resolution hybrid imaging technique to diagnose atherosclerosis and characterize plaque components in mouse is demonstrated and can be easily implemented on commercial ultrasound systems and eventually translated into clinics as a screening tool for atheros sclerosis and the assessment of vulnerable plaques.

7 citations


Cited by
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Journal ArticleDOI
TL;DR: The results of the analyses suggest that disease progression to distant sites does not occur exclusively via the axillary lymph nodes, but rather that lymph node status serves as an indicator of the tumor's ability to spread.
Abstract: Two of the most important prognostic indicators for breast cancer are tumor size and extent of axillary lymph node involvement. Data on 24,740 cases recorded in the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute were used to evaluate the breast cancer survival experience in a representative sample of women from the United States. Actuarial (life table) methods were used to investigate the 5-year relative survival rates in cases with known operative/pathologic axillary lymph node status and primary tumor diameter. Survival rates varied from 45.5% for tumor diameters equal to or greater than 5 cm with positive axillary nodes to 96.3% for tumors less than 2 cm and with no involved nodes. The relation between tumor size and lymph node status was investigated in detail. Tumor diameter and lymph node status were found to act as independent but additive prognostic indicators. As tumor size increased, survival decreased regardless of lymph node status; and as lymph node involvement increased, survival status also decreased regardless of tumor size. A linear relation was found between tumor diameter and the percent of cases with positive lymph node involvement. The results of our analyses suggest that disease progression to distant sites does not occur exclusively via the axillary lymph nodes, but rather that lymph node status serves as an indicator of the tumor's ability to spread.

960 citations

Journal ArticleDOI
B.B. Bauer1
01 Apr 1963

897 citations

Proceedings ArticleDOI
TL;DR: In this article, a semi-analytical finite element (SAFE) method for modeling wave propagation in waveguides of arbitrary cross-section is proposed, and the dispersive solutions are obtained in terms of phase velocity, group velocity, energy velocity, attenuation and cross-sectional mode shapes.

534 citations

Journal ArticleDOI
TL;DR: This manuscript reviews the development and application of nanoparticles and their future potential to advance current and emerging clinical bioimaging techniques, with a focus on solid, phase-separated materials, for example metals and metal oxides.
Abstract: Nanoparticle-based contrast agents are quickly becoming valuable and potentially transformative tools for enhancing medical diagnostics for a wide range of in-vivo imaging modalities. Compared with conventional molecular-scale contrast agents, nanoparticles (NPs) promise improved abilities for in-vivo detection and potentially enhanced targeting efficiencies through longer engineered circulation times, designed clearance pathways, and multimeric binding capacities. However, NP contrast agents are not without issues. Difficulties in minimizing batch-to-batch variations and problems with identifying and characterizing key physicochemical properties that define the in-vivo fate and transport of NPs are significant barriers to the introduction of new NP materials as clinical contrast agents. This manuscript reviews the development and application of nanoparticles and their future potential to advance current and emerging clinical bioimaging techniques. A focus is placed on the application of solid, phase-separated materials, for example metals and metal oxides, and their specific application as contrast agents for in-vivo near-infrared fluorescence (NIRF) imaging, magnetic resonance imaging (MRI), positron emission tomography (PET), computed tomography (CT), ultrasound (US), and photoacoustic imaging (PAI). Clinical and preclinical applications of NPs are identified for a broad spectrum of imaging applications, with commentaries on the future promise of these materials. Emerging technologies, for example multifunctional and theranostic NPs, and their potential for clinical advances are also discussed.

441 citations