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UFFC-S Latin America Webinar Series

4 months 1 week ago
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We are excited to continue our UFFC-S Latin America Webinar Series. Each webinar will feature a short early career talk and a main talk followed by a 10-minute Q&A session. Each webinar will also have translated captions in English, Spanish, and Portuguese. Registration is free and will be limited to the first 300 registrants per event. For more information and registration details, please see below.


Upcoming Webinars

1 September 2022 at 3 PM EDT (UTC -4:00)

Short Early Career Talk (10 Minutes): 
Optically-guided Transcranial Ultrasound Stimulation in Mice

Héctor Estrada 
 ETH Zürich

Main Talk (30 Minutes): 
Acoustic Levitation Methods for Suspending and Manipulating Objects in Mid-Air

Marco A. B. Andrade 
Institute of Physics of the University of São Paulo, Brazil 

Q&A Sesssion (10 Minutes):
Moderator: Dr. Karen Volke-Sepúlveda

Register Here

Short Early Career Talk: 

Optically-guided Transcranial Ultrasound Stimulation in Mice
Transcranial ultrasound neuromodulation is a promising technique with the potential to help us treat and better understand the brain. Current methods of transcranial ultrasound delivery and functional brain imaging in humans cannot provide a detailed account of brain activity under ultrasonic stimulation. In order to know how ultrasound affects the neurons in a living brain, we combined the optical tools developed to image calcium dynamics in mice with precise ultrasound delivery (FLUS). Using a fluoro-thermal tag, we are able to visualize in real-time the position and relative intensity of the ultrasound focus. We hope the FLUS system and our methods can help clarify how ultrasound waves can be exploited in brain therapy and neuroscience.

Héctor Estrada
Héctor Estrada studied Acoustical Engineering in Chile and obtained his Ph.D. on physical acoustics from the Universidad Politecnica de Valencia, Spain, in 2011 investigating the ultrasound propagation through phononic plates. In 2012 he joined the Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München as a postdoctoral fellow developing hybrid optoacoustic-ultrasound neuroimaging system and studying the acoustic properties of the skull using lasers. He currently works at the University and ETH Zurich developing models and techniques for transcranial ultrasound and optoacoustics. His research interests include optoacoustic and ultrasound imaging, guided ultrasonic wave propagation in bone, and ultrasound neuromodulation.

Main Talk:

Acoustic Levitation Methods for Suspending and Manipulating Objects in Mid-Air
Acoustic levitation uses the acoustic radiation force to counteract gravity and suspend objects in the air medium. In this talk, different acoustic levitation approaches will be presented, including the use of standing waves for levitating objects much smaller than the acoustic wavelength, the inverted near-field acoustic levitation method, far-field acoustic levitation method, and the use of single beams generated by arrays of low power transducers. We will also present potential applications, including the manipulation of fragile objects and the contactless manipulation of multiple liquid drops as a tool for liquid processing of small volumes of liquids.

Marco A. B. Andrade
Marco A. B. Andrade is a lecturer at the Institute of Physics of the University of São Paulo, Brazil, and his main research interest is to develop new strategies to levitate and manipulate objects with sound. He received a bachelor’s degree in physics from the Institute of Physics, University of São Paulo, Brazil in 2004, and M.S. and D.Sc. degrees in Mechanical Engineering from Polytechnic School, the University of São Paulo in 2006 and 2010, respectively.  

Moderator:
Dr. Karen Volke-Sepúlveda

Dr. Karen Volke-Sepúlveda got her Ph.D. in Optics in 2003 and she is currently an Associate Professor at the Institute of Physics of the National Autonomous Universidad Nacional Autonoma de Mexico (UNAM). There she established the Optical Micromanipulation Laboratory in 2004, which nowadays has an active research group with two main researchers, postdoctoral fellows, and students of different levels. She lectures at the Faculty of Sciences and in the Physical Sciences Postgraduate Program at UNAM. Her main research topics include optical and acoustical trapping, topological and dynamical properties of structured wavefields, analogies among different wave systems, and nonlinear optical phenomena in colloidal media. Dr. Volke-Sepúlveda has been awarded several recognitions for her research, among them the European Optics Prize 2003 for a paper in which she is the first author. 


Previous Webinars

23 June 2022 at 3 PM EDT (UTC -4:00)

Short Early Career Talk (10 Minutes): 
Pulsed photoacoustics: a powerful non-invasive and non-contact ultrasonic technique for agroindustry applications

David Alejandro Collazos-Burbano
Universidad del Valle, Cali, Colombia

Main Talk (30 Minutes): 
Recent advances in skeletal muscle elastography in the LAU

Nicolás Benech
Physics Institute of the Science School, Universidad de la República (UdelaR) in Montevideo, Uruguay

Q&A Sesssion (10 Minutes):
Moderator: Stefan Catheline

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Short Early Career Talk: 

Pulsed photoacoustics: a powerful non-invasive and non-contact ultrasonic technique for agroindustry applications
Pulsed photoacoustics is a technique which allows for the generation of acoustic waves at ultrasonic frequencies in several materials. It has a huge potential for agroindustry applications, e.g. remote sensing, non-contact and non-destructive characterization, massive data generation and IoT compatibility, among others. This talk presents how this technique can be used to extract elastic properties of plant leaves and to obtain acoustic vegetal indices to determine the water content in the samples under study. The presentation will cover the setting of the experimental apparatus, the determination of the dispersive behavior of the medium and the corresponding extraction of the elastic properties of the samples. This talk will conclude with a discussion about the potential applications in plant hydraulics studies and the assessment of complex biological samples, e.g. plant phenotyping.

David Alejandro Collazos-Burbano
I was born in Dagua, Valle del Cauca, Colombia, in 1988. I received my B. Eng. degree in electronics engineering, and my M. Eng. from the Universidad del Valle, Cali, Colombia. Currently, I am a Ph.D. candidate at the same University. I had a Young Researcher fellowship from COLCIENCIAS, Colombia, in 2013. I took part in a youth stay of excellence at the Research Center in Optics (CIO), León, Guanajuato, Mexico, in 2016. Also, I received the best student paper award at the 2021 IEEE Latin America Ultrasonic Symposium (LAUS).

Since 2017 I have been a researcher at the Center for Bioinformatics and Photonics (CIBioFi), Cali, Colombia. Currently, I am working with guided and non-guided acoustic waves to extract elastic properties of plant leaves in a contactless way. My research interests include digital signal processing, air-coupled ultrasound, pulsed photoacoustics, ultrasound applications in agroindustry, and modeling of the interaction between acoustic waves and plant tissues.
 

Main Talk:

Recent advances in skeletal muscle elastography in the LAU 
In this talk, I will review the most recent work related to elastography applied to skeletal muscle, developed at the Laboratorio de Acústica Ultrasonora (LAU) in Montevideo, Uruguay. Elastography in muscles is challenging because of anisotropy and viscosity. The simplest case to deal with is the SH propagation mode where polarization of the shear wave (SW) is perpendicular to the fibers. For such mode, the shear wave velocity (SWV) depends on the angle between the propagation direction and the fibers’ direction. In US elastography, a push beam (PB) generates the SW and ultrafast imaging is used to track its propagation. The SW attenuates with distance due to diffraction and viscosity. We are working on a diffraction model for the PB, based on Green’s function for transversely isotropic solids, to discriminate those effects in the experimental data and be able to estimate the tissue viscosity. 

The SW can also be generated by using external sources. For superficial muscles, most parts of the energy propagate as a surface wave. Thus, the shear elasticity can be estimated if a relationship between the velocity of surface waves and the SWV can be established. This relationship depends on the geometry of the tissue but also on near-field effects. These effects generate a dispersion curve even in a semi-infinite solid and thus, must be considered to retrieve the SWV. I will show examples of the application of surface waves in beef samples (ex vivo) as well as in biceps branchii (in vivo).  

Finally, I will show the results of 3D shear elasticity imaging using an RCA probe and a Vantage Verasonics System, based in a passive elastography approach. We conducted experiments in a CIRS phantom and in the forearm muscles of a healthy volunteer. Results are encouraging but there are still some issues to be addressed.   

Nicolás Benech
Nicolás Benech is Professor at the Physics Institute of the Science School, Universidad de la República (UdelaR) in Montevideo, Uruguay. He teaches wave physics to undergraduate and graduate students, including Ph.D. His research interest areas include physical acoustics, wave propagation in soft solids, and ultrasound elastography. He holds one patent related to surface wave elastography applied in the beef industry.  Currently, he is the head of the physics area of the “Programa para el Desarrollo de las Ciencias Básicas, (PEDECIBA)”, a government program that funds researchers and graduate students in physics. 
 

Moderator:
Stefan Catheline 

Stefan Catheline received the Diplome d’Etudes Approfondies (M.Sc. degree) in physics and acoustics (1994), his PhD degree in physics (1998) from University of Paris VII (Denis Diderot) for his work on transient elastography and his “Habilitation de Recherche” in 2006. 
After a post doc at the University of California, San Diego, he become an assistant Professor at University of Paris VII in 1999 and joined the laboratory Ondes et Acoustique (now Institut Langevin) at the Ecole Supérieure de Physique et de Chimie Industrielle de la Ville de Paris (ESPCI). From 2005, he has been working for a two years mission at the University of Montevideo (Uruguay) and was assistant Professor at University of Grenoble at Isterre until 2012. He is now Director of research at INSERM unit 1032, in the Laboratory of Therapeutic Applications of Ultrasound (LabTAU) directed by Cyril Lafon in Lyon. His current research activities at the head of the team “Ondes et instrumentation” include acoustic topics such as elastography, time reversal, seismology, reverberant cavities, nonlinear elasticity, tactile interface, source localization as well as HIFU. He holds 8 patents in the field of ultrasound and seismology and wrote more than 100 articles. He has been co-founder of two companies: Sensitive Object in the field of acoustic interactivity and SEISME in the field of elastography. He is a member of the technical program committee of the IEEE International Ultrasonics Symposium.