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Akhbari S.,University of California at Berkeley | Voie A.,BURL Concepts Inc. | Li Z.,University of California at Berkeley | Li Z.,Xian University of Science and Technology | And 2 more authors.
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) | Year: 2016

A CMOS-compatible, aluminum nitride (AlN) based, dual-electrode bimorph piezoelectric micromachined ultrasonic transducer (pMUT) array has been developed. Under an input 5Vac driving voltage, a high acoustic intensity of 30-70mW/cm2 up to 2.5mm deep into tissues can be generated for therapeutic medical applications. The low driving voltage is readily applicable for battery-powered low intensity pulsed ultrasound (LIPUS) medical devices for fracture and tissue healing applications. The fabrication also introduces a novel method using PECVD SiO2 as the barrier layer between AlN films to increase the breakdown voltage and manufacturing yield. Results on a prototype array have shown the highest intensity per voltage squared, per number of pMUTs squared, per piezoelectric constant squared (i.e. I=I/(VNd31)2) among all reported pMUT arrays. © 2016 IEEE.

BURL Concepts Inc. | Date: 2015-09-09

Medical ultrasound apparatus, namely, portable, battery-powered ultrasound device designed for the non-invasive, transcranial diagnosis of strokes.

BURL Concepts Inc. | Date: 2016-05-26

Medical ultrasound apparatus, namely, portable, battery-powered ultrasound device designed for the non-invasive, transcranial diagnosis of strokes.

Lapchak P.A.,Cedars Sinai Medical Center | Boitano P.D.,Cedars Sinai Medical Center | Butte P.V.,Cedars Sinai Medical Center | Fisher D.J.,BURL Concepts Inc. | And 5 more authors.
PLoS ONE | Year: 2015

Background and Purpose Transcranial near-infrared laser therapy (TLT) is a promising and novel method to promote neuroprotection and clinical improvement in both acute and chronic neurodegenerative diseases such as acute ischemic stroke (AIS), traumatic brain injury (TBI), and Alzheimer's disease (AD) patients based upon efficacy in translational animal models. However, there is limited information in the peer-reviewed literature pertaining to transcranial near-infrared laser transmission (NILT) profiles in various species. Thus, in the present study we systematically evaluated NILT characteristics through the skull of 4 different species: mouse, rat, rabbit and human. Results Using dehydrated skulls from 3 animal species, using a wavelength of 800nm and a surface power density of 700 mW/cm2, NILT decreased from 40.10% (mouse) to 21.24% (rat) to 11.36% (rabbit) as skull thickness measured at bregma increased from 0.44 mm in mouse to 0.83 mm in rat and then 2.11 mm in rabbit. NILT also significantly increased (p<0.05) when animal skulls were hydrated (i.e. compared to dehydrated); but there was no measurable change in thickness due to hydration. In human calvaria, where mean thickness ranged from 7.19 mm at bregma to 5.91 mm in the parietal skull, only 4.18% and 4.24% of applied near-infrared light was transmitted through the skull. There was a slight (9.2-13.4%), but insignificant effect of hydration state on NILT transmission of human skulls, but there was a significant positive correlation between NILT and thickness at bregma and parietal skull, in both hydrated and dehydrated states. Conclusion This is the first systematic study to demonstrate differential NILT through the skulls of 4 different species; with an inverse relationship between NILT and skull thickness. With animal skulls, transmission profiles are dependent upon the hydration state of the skull, with significantly greater penetration through hydrated skulls compared to dehydrated skulls. Using human skulls, we demonstrate a significant correlation between thickness and penetration, but there was no correlation with skull density. The results suggest that TLT should be optimized in animals using novel approaches incorporating human skull characteristics, because of significant variance of NILT profiles directly related to skull thickness. © 2015 Lapchak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Voie A.,BURL Concepts Inc. | Dirnbacher M.,BURL Concepts Inc. | Fisher D.,BURL Concepts Inc. | Holscher T.,BURL Concepts Inc. | Holscher T.,University of California at San Diego
Computerized Medical Imaging and Graphics | Year: 2014

In this paper we report how thickness and density vary over the calvarium region of a collection of human skulls. Most previous reports involved a limited number of skulls, with a limited number of measurement sites per skull, so data in the literature are sparse. We collected computer tomography (CT) scans of 51 ex vivo human calvaria, and analyzed these in silico using over 2000 measurement sites per skull. Thickness and density were calculated at these sites, for the three skull layers separately and combined, and were mapped parametrically onto the skull surfaces to examine the spatial variations per skull. These were found to be highly variable, and unique descriptors of the individual skulls. Of the three skull layers, the thickness of the inner cortical layer was found to be the most variable, while the least variable was the outer cortical density. © 2014 Elsevier Ltd.

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