https://nojigon.webs.upv.es/papers.htmlJournal articles from the BibTeX bibliography of Noé Jiménez.enhttps://nojigon.webs.upv.es/publications/chaplainjphysd2025.htmlhttps://nojigon.webs.upv.es/publications/chaplainjphysd2025.html2025 · G. J. Chaplain, F. Langfeldt, V. Romero-García, N. Jiménez, Y. Meng, J. Boulvert, J.P. Groby, V. Pagneux, D.B. Moore, A. P. Hibbins, J. R. Sambles, T. A. Starkey, B. Popa, Z. Zhang, J. Christensen, X. Wen, J. Li, R. Fleury, S. P. Wallen, M. R. Haberman, M. I. Hussein, G. Memoli, G. Fusaro, D. D’Orazio, L. Barbaresi, M. Garai, L. Chisari, P. Mittal, Z. Qi, S. Subramanian, S. Brûlé, S. Enoch, S. Guenneau, R. Stoakes, C. McLean, A. Gardiner Today, acoustic metamaterials (AMMs) form a core area of metamaterial research. They offer bespoke wave control, achievable through their rationally designed structure and are at the forefront of metamaterial applications and commercialisation. They find purpose across science and defence sectors in wave filtering, sensing, communications, energy harvesting, thermal emission control, and aeroacoustics, to name but a few. They enjoy success in metropolitan environments with designer audio and noise mitigation falling within their remit; AMM technologies are already penetrating the market across audio and healthcare sectors. The landscape of AMM research is continually expanding, now incorporating several wave regimes under a broader definition that we adopt here. The diversity of AMM research displays how they exist not only to translate electromagnetic phenomena, but also to provide a unique platform for exploring all metamaterial physics, and for solving key societal challenges. The aim of this Roadmap is to present a summary of the state of AMM research and innovation in 2024, with opinions on the challenges and future opportunities from a group of renowned experts, covering key interdisciplinary areas from fundamental acoustics to device implementation.https://nojigon.webs.upv.es/publications/lopezberenguertrpms2025.htmlhttps://nojigon.webs.upv.es/publications/lopezberenguertrpms2025.html2025 · Fernando Lopez-Berenguer, Andrea Gonzalez-Montoro, Marta Freire, Adolfo Gonzalez-Tamarit, Santiago Jimenez-Serrano, Luis F Vidal, Marc Gil, Francis Loignon-Houle, Irene Torres, Jennifer L Sachs, Joseph Rispoli, Nick Tustinson, Stuart S Berr, Mark B Williams, Diana Andres, Juan Jose Rodriguez-Garcia, Jose Luis Alonso-Ramos, Noé Jiménez, Alicia Carrión, Francisco Camarena, Teresa Guallart-Naval, Jose Miguel Algarin, Ruben Bosch, Eduardo Pallas, Joseba Alonso, Natasha Sheybani, Stef Maslova, Thomas Sherlock, Andrew Thede, Zhera Demir, Matt Hoch, He Jiang, Jose M Benlloch, Maria Jose Rodriguez-Alvarez, Antonio J. González Combining Positron Emission Tomography (PET) with Magnetic Resonance Imaging (MRI) and Focused Ultrasound (FUS) has emerged as a promising hybrid technique in the medical imaging field. Despite the potential benefits of using simultaneous PET and MRI acquisitions to monitor therapeutic effects and ensure precision and safety during FUS applications, no commercial or academic PET/MRI-guided FUS system (referred in the following as trimodal PET-MRI-FUS) exists. This work presents the design and evaluation of a preclinical PET insert for simultaneous operation with MRI and FUS systems. The proposed PET insert is based on monolithic LYSO crystals arranged in two octagonal rings that define inner and outer diameters of 72 mm and 114 mm, respectively, with an axial length of 67 mm. The system performance was evaluated according to the NEMA NU 4 2008 protocol. It achieves a uniform spatial resolution of ~0.9 mm along the whole PET Field of View (FOV) when enabling Depth of Interaction (DOI) capabilities. Moreover, we found a sensitivity peak of 3.8% for an energy window of 255-766 keV and a peak noise equivalent count rate peak of 80 kcps at an activity of 19 MBq. The compatibility of the PET insert with both low-and high-field MRI systems, as well as with custom and commercially available FUS devices, was studied using phantoms and in vivo experiments, respectively. The results of the trimodal tests have proven that the PET insert works simultaneously with both MRI and FUS systems.https://nojigon.webs.upv.es/publications/pi2025.htmlhttps://nojigon.webs.upv.es/publications/pi2025.html2025 · Irene Pi-Martín, Carla Vidaurre-Agut, Eva María Rivero-Buceta, Alejandro Cebrecos, Juan José García-Garrigós, Noé Jiménez, José María Benlloch, Pablo Botella, Francisco Camarena Photoacoustic imaging (PAI) is an emerging biomedical modality offering non-invasive, high-resolution imaging with molecular contrast. Its effectiveness for molecular imaging is improved by using external contrast agents such as dyes and nanostructures, which enable targeted imaging, deeper tissue penetration, and enhanced diagnostic accuracy. However, the clinical translation of these agents has been hindered by limitations in biocompatibility, biodegradability, and functionalization versatility. In this study, two porphyrin-free nanoscale covalent organic frameworks (nCOFs), TAPB-PDA and LZU-1, were evaluated as novel exogenous contrast agents for PAI. Their photoacoustic responses were systematically measured and compared with traditional contrast agents, such as gold nanoparticles (AuNPs) and ATTO532-labelled mesoporous silica nanoparticles. Experiments at 532 nm across a range of concentrations demonstrated strong photoacoustic signals from TAPB-PDA and LZU-1, with enhanced response at higher concentrations. Besides, both nCOFs also provided detectable signals at the NIR window at the lowest concentration, indicating a broad working range. A nonlinear model of the volume-integrated photoacoustic pressure is also provided. Furthermore, in vitro cytotoxicity assays indicated excellent nCOF biocompatibility, even at higher concentrations. Photostability tests under prolonged pulsed laser irradiation revealed that both nCOFs exhibit good resistance to photobleaching and partial signal recovery under intermittent excitation. Collectively, these findings highlight the potential of TAPB-PDA and LZU-1 nCOFs as biocompatible, biodegradable, and functionally versatile contrast agents for advanced photoacoustic imaging.https://nojigon.webs.upv.es/publications/gonzalezcmpb2024.htmlhttps://nojigon.webs.upv.es/publications/gonzalezcmpb2024.html2025 · Enrique González-Mateo, Francisco Camarena, Noé Jiménez Current approaches for ultrasound spectral elastography make use of block processing, resulting in long computational times. This work describes a real-time, robust, and quantitative imaging modality to map the elastic and viscoelastic properties of soft tissues using ultrasound. This elastographic technique relies on the spectral estimation of the shear-wave phase speed by combining a local phase-gradient method and angular filtering. We first apply directional filtering in the spatio-temporal frequency domain for providing one-way, smooth, and harmonic displacement maps in the frequency range of interest. Thanks to this, we can apply a simple, fast, and local phase gradient approach to obtain the axial and lateral components of the wavevector, which are linked to phase velocity and soft-tissue elasticity and viscoelasticity. The technique is validated numerically and experimentally using a 7.5 MHz ultrasound probe, tested in calibrated soft tissue phantoms and ex vivo liver tissues. The method is compared with state-of-the-art spectral methods. The technique significantly reduces the computation time, e.g., the reconstruction time for a 155x315-pixel phase-velocity map was 0.16 seconds, while local-phase velocity-imaging techniques was 156.73 s for 2D implementation and 13.56 s for the 1D version, a reduction between two and three orders of magnitude, while showing a similar accuracy and resolution than standard methods. This approach eliminates the need for block processing that may limit the spatial resolution and computational time of the velocity map. In this way, the phase gradient elastography method is revealed as an efficient and robust approach for real-time spectral elastography.https://nojigon.webs.upv.es/publications/ballesteroafm2025.htmlhttps://nojigon.webs.upv.es/publications/ballesteroafm2025.html2025 · Eric Ballestero, Josep Rodriguez-Sendra, Vicent Romero-García, Jean-Philippe Groby, Noé Jiménez Abstract Acoustic holography enables the creation of tailored spatiotemporal wavefield distributions. In this study, the design of acoustic holograms that simultaneously control both the reflected and the transmitted fields are presented. This is accomplished through the use of a bidirectional metasurface, which encodes the phase of a desired wavefront in a discrete spatial distribution of monolithic sub-elements. This approach is employed in particular to design an optimized hologram that behaves as an ideal Lambertian scatter for both reflection and transmission. The design follows a quadratic-residue sequence, with theoretical results validated both numerically and experimentally. It is observed that this kind of structure produces a uniform scattering response, with a high diffusion coefficient of approximately 0.7 and a correlation scattering coefficient of 0.98 in both transmission and reflection. The hologram demonstrates the potential to significantly reduce imaging artefacts in ultrafast ultrasound techniques in strongly reverberating environments, as evidenced by examples.https://nojigon.webs.upv.es/publications/burstlowpmb2025.htmlhttps://nojigon.webs.upv.es/publications/burstlowpmb2025.html2025 · Rachel Burstow, Diana Andrés, Noé Jiménez, Francisco Camarena, Maya Thanou, Antonios N. Pouliopoulos Acoustic holography can be used to construct an arbitrary wavefront at a desired 2D plane or 3D volume by beam shaping an emitted field and is a relatively new technique in the field of biomedical applications. Acoustic holography was first theorized in 1985 following Gabor’s work in creating optical holograms in the 1940s. Recent developments in 3D printing have led to an easier and faster way to manufacture monolithic acoustic holographic lenses that can be attached to single-element transducers. As ultrasound passes through the lens material, a phase shift is applied to the waves, causing an interference pattern at the 2D image plane or 3D volume, which forms the desired pressure field. This technology has many applications already in use and has become of increasing interest for the biomedical community, particularly for treating regions that are notoriously difficult to operate on, such as the brain. Acoustic holograms could provide a non-invasive, precise, and patient specific way to deliver drugs, induce hyperthermia, or create tissue cell patterns. However, there are still limitations in acoustic holography, such as the difficulties in creating 3D holograms and the passivity of monolithic lenses. This review aims to outline the biomedical applications of acoustic holograms reported to date and discuss their current limitations and the future work that is needed for them to reach their full potential in the biomedical community.https://nojigon.webs.upv.es/publications/lamotheappliedacoustics2024.htmlhttps://nojigon.webs.upv.es/publications/lamotheappliedacoustics2024.html2024 · Nathalie Lamothe, Diana Andrés, Alicia Carrión, Francisco Camarena, José A. Pineda-Pardo, Noé Jiménez Acoustic holograms can generate cavitation patterns of complex spatial distribution by shaping and steering the focal spot of therapeutic ultrasound systems. However, when monitoring these systems by passive cavitation detection, off-axis therapeutical targets and the receiver directivity may not be aligned. In this paper, we present passive cavitation beamforming to monitor a therapeutical ultrasound system using holograms targeted to arbitrary locations, in which both therapeutic and passive cavitation monitoring systems use 3D-printed acoustic lenses. The therapeutic system uses an acoustic hologram to focus the ultrasound beam on the target, which is off-axis. Then, a second lens is designed to beamform the cavitation signals which emerge from the therapeutic target, steering the directivity of the passive cavitation detector in the direction of the therapeutic focus and, in addition, compensating for skull aberrations. The system is experimentally tested with an ex-vivo macaque skull and a blood vessel phantom with microbubbles. In addition, results are compared with a standard confocal configuration and an off-axis configuration in the absence of the monitor lens. A parametric study is performed by varying the amplitude of the emitted signal and the impact on the behaviour of the microbubbles is analysed based on the cavitation index values. Results show that monitoring holograms align the passive cavitation detector response with the focal spot of the targeted therapeutic transducer. These holograms encode a fixed beamformer for cavitation signals in reception, increasing the sensitivity of cavitation emission at the target. In this way, cavitation doses can be used to locally monitor the cavitation activity of microbubbles, thus opening a new path to low-cost monitoring of therapeutic ultrasound systems.https://nojigon.webs.upv.es/publications/pimartinphotoacoustics2023.htmlhttps://nojigon.webs.upv.es/publications/pimartinphotoacoustics2023.html2023 · Irene Pi-Martín, Alejandro Cebrecos, Juan J. García-Garrigós, Noé Jiménez, Francisco Camarena Limitations associated with linear-array probes in photoacoustic tomography are partially compensated by using advanced beamformers that exploit the temporal and spatial coherence of the recorded signals, such as Delay Multiply and Sum (DMAS), Minimum Variance (MV) or coherence factor (CF), among others. However, their associated signal processing leads to an overestimation of the spatial resolution, as well as alterations in the reconstructed object size. Numerical and experimental results reported here support this hypothesis. First, we show that the Rayleigh criterion (RC) is the most suitable choice to characterize the spatial resolution instead of the Point Spread Function (PSF) when considering advanced beamformers. Then, we observe that several advanced beamformers fail to properly reconstruct target sizes slightly above the spatial resolution, underestimating their size. This work sheds light on the suitability of this type of beamformers combined with linear probes for determining sizes and morphology in photoacoustic images.https://nojigon.webs.upv.es/publications/andresprapp2023.htmlhttps://nojigon.webs.upv.es/publications/andresprapp2023.html2023 · Diana Andrés, Alicia Carrión, Francisco Camarena, Noé Jiménez Ultrasonic three-dimensional printed holograms are getting increasing interest for transcranial therapies since they can correct skull aberrations and, simultaneously, adapt the acoustic field to particular brain targets. However, evaluating the targeting performance of these systems requires the measurement of complex volumetric acoustic fields, which in many practical situations cannot be estimated by direct hydrophone measurements. In this work, we apply single-plane holographic measurement techniques to experimentally calibrate and measure the full volumetric field produced by holographic lenses. Two ex vivo test cases are presented, a four-foci lens and a preclinical case, both targeting through a macaque skull for potential applications in blood–brain barrier opening (BBBO) studies. Time-reversal and angular spectrum projection methods are compared to direct experimental measurements. Results show that holographic projection methods can reconstruct the complex acoustic images produced by holographic lenses, matching direct measurements in all test cases. However, while direct measurements are restricted to transverse-field cross sections, holographic projection allows estimating the field on the whole targeting volume. In this way, the location and the full three-dimensional shape of all acoustic foci can be obtained. Furthermore, these techniques can provide the field at the surface of the lens to compare it to the design phase distribution. Using this procedure, complex volumetric acoustic fields can be reconstructed, saving significant measurement time and computational resources, and enabling an accurate characterization of phase plates and other holographic lens topologies.https://nojigon.webs.upv.es/publications/gonzalezmateosea2023.htmlhttps://nojigon.webs.upv.es/publications/gonzalezmateosea2023.html2023 · Enrique M. González-Mateo, Josep Rodríguez-Sendra, Francisco Camarena, Noé Jiménez Ultrasound elastography is a medical imaging technique that assesses and maps the elasticity of soft tissues. Elastography provides qualitative and quantitative diagnostic information using specialized imaging modes that measure stiffness in response to mechanical forces. This modality presents high sensitivity and specificity because many pathologies result in large changes in tissue stiffness, being particularly useful in liver fibrosis and detection and quantification of tumors such as breast, thyroid, or prostate. In this summary we present the basic principles of ultrasound elastography, its clinical relevance, and review the new elasticity mapping imaging techniques.https://nojigon.webs.upv.es/publications/pisea2023.htmlhttps://nojigon.webs.upv.es/publications/pisea2023.html2023 · Irene Pi-Martín, Carla M. Vidaurre-Agut, Alejandro Cebrecos, Juan J. García-Garrigós, Noé Jiménez, Pablo Botella, Francisco Camarena Photoacoustic imaging allows obtaining molecular and functional images in any biological medium. Using endogenous contrasts is possible to study natural processes and using exogenous chromophores, typically gold nanoparticles, it is possible to improve the quality of the images obtained or even use them as markers of specific pathophysiological targets. In this work we explored the wide range of chromophores used in photoacoustic imaging, especially delving into the feasibility of using nanoparticles of covalent organic networks (nCOFs) as biocompatible and completely harmless exogenous contrast agents. For this purpose, the response of two types of nCOFs has been compared with the current standard. The results obtained point to both types of nCOFs as very promising contrast agents for photoacoustic imaging due to their satisfactory response and biocompatibility. The use of biocompatible nCOFs will make it possible to obtain high quality molecular images using high contrast doses and minimizing side effects.https://nojigon.webs.upv.es/publications/andrescancers2023.htmlhttps://nojigon.webs.upv.es/publications/andrescancers2023.html2023 · Diana Andrés, Ian Rivens, Petros Mouratidis, Noé Jiménez, Francisco Camarena, Gail Ter Haar Hyperthermia is currently used to treat cancer due to its ability to radio- and chemo-sensitize and to stimulate the immune response. While ultrasound is non-ionizing and can induce hyperthermia deep within the body non-invasively, achieving uniform and volumetric hyperthermia is challenging. This work presents a novel focused ultrasound hyperthermia system based on 3D-printed acoustic holograms combined with a high-intensity focused ultrasound (HIFU) transducer to produce a uniform iso-thermal dose in multiple targets. The system is designed with the aim of treating several 3D cell aggregates contained in an International Electrotechnical Commission (IEC) tissue-mimicking phantom with multiple wells, each holding a single tumor spheroid, with real-time temperature and thermal dose monitoring. System performance was validated using acoustic and thermal methods, ultimately yielding thermal doses in three wells that differed by less than 4%. The system was tested in vitro for delivery of thermal doses of 0–120 cumulative equivalent minutes at 43 °C (CEM43) to spheroids of U87-MG glioma cells. The effects of ultrasound-induced heating on the growth of these spheroids were compared with heating using a polymerase chain reaction (PCR) thermocycler. Results showed that exposing U87-MG spheroids to an ultrasound-induced thermal dose of 120 CEM43 shrank them by 15% and decreased their growth and metabolic activity more than seen in those exposed to a thermocycler-induced heating. This low-cost approach of modifying a HIFU transducer to deliver ultrasound hyperthermia opens new avenues for accurately controlling thermal dose delivery to complex therapeutic targets using tailored acoustic holograms. Spheroid data show that thermal and non-thermal mechanisms are implicated in the response of cancer cells to non-ablative ultrasound heating.https://nojigon.webs.upv.es/publications/krushynska2023.htmlhttps://nojigon.webs.upv.es/publications/krushynska2023.html2023 · Anastasiia O. Krushynska, Daniel Torrent, Alejandro M. Aragón, Raffaele Ardito, Osama R. Bilal, Bernard Bonello, Federico Bosia, Yi Chen, Johan Christensen, Andrea Colombi, Steven A. Cummer, Bahram Djafari-Rouhani, Fernando Fraternali, Pavel I. Galich, Pedro David Garcia, Jean-Philippe Groby, Sebastien Guenneau, Michael R. Haberman, Mahmoud I. Hussein, Shahram Janbaz, Noé Jiménez, Abdelkrim Khelif, Vincent Laude, Mohammad J. Mirzaali, Pawel Packo, Antonio Palermo, Yan Pennec, Rubén Picó, María Rosendo López, Stephan Rudykh, Marc Serra-Garcia, Clivia M. Sotomayor Torres, Timothy A. Starkey, Vincent Tournat, Oliver B. Wright This broad review summarizes recent advances and "hot" research topics in nanophononics and elastic, acoustic, and mechanical metamaterials based on results presented by the authors at the EUROMECH 610 Colloquium held on April 25–27, 2022 in Benicássim, Spain. The key goal of the colloquium was to highlight important developments in these areas, particularly new results that emerged during the last two years. This work thus presents a "snapshot" of the state-of-the-art of different nanophononics- and metamaterial-related topics rather than a historical view on these subjects, in contrast to a conventional review article. The introduction of basic definitions for each topic is followed by an outline of design strategies for the media under consideration, recently developed analysis and implementation techniques, and discussions of current challenges and promising applications. This review, while not comprehensive, will be helpful especially for early-career researchers, among others, as it offers a broad view of the current state-of-the-art and highlights some unique and flourishing research in the mentioned fields, providing insight into multiple exciting research directions.https://nojigon.webs.upv.es/publications/andresmsel2022.htmlhttps://nojigon.webs.upv.es/publications/andresmsel2022.html2022 · Diana Andrés, Francisco Camarena, Noé Jiménez When a surface vibrates compressing the medium on its front, it generates acoustic waves. This is the case of loudspeakers, which generate acoustic waves at audible frequencies by means of a moving surface. In this paper we present a tutorial to model the acoustic radiation of vibrating surfaces, differentiating between flat and curved circular geometries. First, we derive the models describing the radiation of moving surfaces, and we will obtain analytical solutions for the simplest cases. For the complex ones, the model will be integrated numerically. Both solutions have been incorporated into a simple graphical interface, with which the acoustic field generated by the different surfaces can be visualized by varying their radiation characteristics. The proposed methodology allows to deepen in the analysis of acoustic wave radiation, and to present an example of modeling for Acoustics students, from modeling to obtaining analytical and numerical solutions.https://nojigon.webs.upv.es/publications/pisea2022.htmlhttps://nojigon.webs.upv.es/publications/pisea2022.html2022 · Irene Pi-Martín, Juan J. García-Garrigós, Alejandro Cebrecos, Noé Jiménez, Francisco Camarena Photoacoustic tomography (PAT) is an emerging biomedical imaging modality with great clinical potential that combines the use of optical and acoustic techniques for high-resolution imaging of biological tissues. The technique consists in illuminating a tissue using a pulsed laser beam causing local heating of the tissue. Due to the photoacoustic effect, in which optical energy is absorbed and converted into acoustic energy by thermoelastic expansion of the tissue, the rarefaction of the tissue produces a pulsed ultrasonic signal that can be measured with a phased array transducer and converted into images using reconstruction algorithms. To reconstruct the images, beamforming algorithms such as the delay and sum beamformer are used, which is computationally efficient and simple to implement, although it offers low image resolution and contrast. To overcome these limitations, improvements have been made to obtain better image quality. These improvements are based on combining the signals from the different elements, windowing the signal, or even calculating the optimal apodization for each pixel based on the signals received by the ultrasonic elements. This work is a numerical and experimental study that uses lateral and axial resolution and signal-to-noise ratio to evaluate the performance of the main reconstruction algorithms used in PAT. The results show how the adaptive algorithms allow to improve the axial and lateral resolution with respect to the delay and sum beamformer, but in certain situations the size of the objects in the image does not correspond to their real size, which can limit their effectiveness in the quantification of the size of biological structures.https://nojigon.webs.upv.es/publications/andres2022.htmlhttps://nojigon.webs.upv.es/publications/andres2022.html2022 · Diana Andrés, Noé Jiménez, José M. Benlloch, Francisco Camarena Acoustic holograms can encode complex wavefronts to compensate the aberrations of a therapeutical ultrasound beam propagating through heterogeneous tissues such as the skull and, simultaneously, they can generate diffraction-limited acoustic images, i.e., arbitrary shaped focal spots. In this work, we numerically study the performance of acoustic holograms focusing at the thalamic nuclei when the source is located at the temporal bone window. The temporal window is the thinnest area of the lateral skull and it is mainly hairless, so it is a desirable area to transmit ultrasonic waves to the deep brain. However, targeting from this area the bilateral thalamic nuclei are not aligned with the elongated focal spots of conventional focused transducers and, in addition, skull aberrations can distort the focal spot. We found that using holographic lenses coupled to a single-element 650-kHz frequency 65-mm aperture source, the focal spot can be sharply adapted to the thalamic nuclei in a bilateral way while skull aberrations are mitigated. Furthermore, it was studied the performance of these holograms under misalignment errors between the source and the skull, concluding that for misalignments up to 5 degrees acoustic images are correctly restored. This work paves the way to design clinical applications of transcranial ultrasound such as blood-brain barrier opening for drug delivery or deep-brain neuromodulation using this low-cost technology, presenting desirable aspects for long-term treatments because the patient head does not need to be shaved completely.https://nojigon.webs.upv.es/publications/gambin2021.htmlhttps://nojigon.webs.upv.es/publications/gambin2021.html2022 · Sergio Jiménez-Gambín, Noé Jiménez, Antonios N. Pouliopoulos, José M. Benlloch, Elisa E. Konofagou, Francisco Camarena Transcranial focused ultrasound (FUS) in conjunction with circulating microbubbles injection is the sole non-invasive technique that temporally and locally opens the blood-brain barrier (BBB), allowing targeted drug delivery into the central nervous system (CNS). However, single-element FUS technologies do not allow the simultaneous targeting of several brain structures with high-resolution, and multi-element devices are required to compensate the aberrations introduced by the skull. In this work, we present the first preclinical application of acoustic holograms to perform a bilateral BBB opening in two mirrored regions in mice. The system consisted of a single-element focused transducer working at 1.68 MHz, coupled to a 3D-printed acoustic hologram designed to produce two symmetric foci in anesthetized mice in vivo and, simultaneously, compensate the aberrations of the wavefront caused by the skull bones. T1-weighed MR images showed gadolinium extravasation at two symmetric quasi-spherical focal spots. By encoding time-reversed fields, holograms are capable of focusing acoustic energy with a resolution near the diffraction limit at multiple spots inside the skull of small preclinical animals. This work demonstrates the feasibility of hologram-assisted BBB opening for low-cost and highly-localized targeted drug delivery in the CNS in symmetric regions of separate hemispheres.https://nojigon.webs.upv.es/publications/kontenis2022.htmlhttps://nojigon.webs.upv.es/publications/kontenis2022.html2022 · Gabrielius Kontenis, Darius Gailevicius, Noé Jimenéz, and Kestutis Staliunas One of the key trends in laser material processing is the usage of structured laser beams. Collimated and focused Gaussian beams are the most common tools; however, more exotic beams can be beneficial too. For instance, Bessel beams with elongated focal area and self-healing properties, or vortex beams with helical wave fronts and a dark area along the optical axis are being increasingly used. Here, we propose and experimentally demonstrate dynamical "optical drill" beams presenting nonstationary intensity distributions that resemble a spinning mechanical drill. Optical drills appear as the spatiotemporal interference of two Bessel-vortex beams of different topological charges and different carrier frequencies. By mixing a pair of high-order Bessel beams, synthesized using a liquid crystal spatial light modulator, optical drills of tuned helicities are experimentally observed, and the simplest cases of matter processing (fluorescence) with such beams are demonstrated. Optical drill beams are expected to be useful in material processing by light or in cell and particle manipulation in biomedical applications.https://nojigon.webs.upv.es/publications/andresapl2022.htmlhttps://nojigon.webs.upv.es/publications/andresapl2022.html2022 · Diana Andrés, Jonathan Vappou, Noé Jiménez, Francisco Camarena Holograms can shape wavefronts to produce arbitrary acoustic images. In this work, we experimentally demonstrate how acoustic holograms can produce controlled thermal patterns in absorbing media at ultrasonic frequencies. Magnetic resonance imaging (MRI)-compatible holographic ultrasound lenses were designed by time-reversal methods and manufactured using 3D-printing. Several thermal holographic patterns were measured using MRI thermometry and a thermographic camera in gelatin-milk phantoms and in an ex vivo liver tissue. The results show that acoustic holograms enable spatially controlled heating in arbitrary regions. Increasing the temperature using low-cost and MRI-compatible holographic transducers might be of great interest for many biomedical applications, such as ultrasound hyperthermia, where the control of specific thermal patterns is needed.https://nojigon.webs.upv.es/publications/ballestero2021b.htmlhttps://nojigon.webs.upv.es/publications/ballestero2021b.html2021 · Eric Ballestero, Brian Hamilton, Noé Jimenez, Vicent Romero-García, Jean-Philippe Groby, Haydar Aygün, Stephen Dance Most simulations involving metamaterials often require complex physics to be solved through refined meshing grids. However, it can prove challenging to simulate the effect of local physical conditions created by said metamaterials into much wider computing sceneries due to the increased meshing load. We thus present in this work a framework for simulating complex structures with detailed geometries, such as metamaterials, into large Finite-Difference Time-Domain (FDTD) computing environments by reducing them to their equivalent surface impedance represented by a parallel-series RLC circuit. This reduction helps to simplify the physics involved as well as drastically reducing the meshing load of the model and the implicit calculation time. Here, an emphasis is made on scattering comparisons between an acoustic metamaterial and its equivalent surface impedance through analytical and numerical methods. Additionally, the problem of fitting RLC parameters to complex impedance data obtained from transfer matrix models is herein solved using a novel approach based on zero crossings of admittance phase derivatives. Despite the simplification process, the proposed framework achieves good overall results with respect to the original acoustic scatterer while ensuring relatively short simulation times over a vast range of frequencies