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Foodborne diseases are indisputable risks to human health, as they are directly affected by the consumption of food and beverages exposed to spoiling and pathogenic microorganisms. A commonly confronted issue by the food industry is the use of synthetic additives to control microbial growth on food products. Alternatively, plant essential oils (EOs) are natural compounds with antimicrobial effects against pathogens in edible and drinkable products. Based on bacteriostatic and bactericidal activities, this review describes the antimicrobial effects of plant EOs on Listeria monocytogenes, also indicating their potential applicability in different food products. Conclusively, it is determined that the Gram-positive bacteria have more susceptibilities to the EOs. In addition, the antibacterial efficacy of the EOs reported in the literature varied according to several parameters, including the seasonal harvest of plants, well-settled methodologies for extraction of EOs, experimental conditions for testing the antibacterial effect on L. monocytogenes, and matrix effects considering several types of foodstuffs. This later represents the main challenge to be addressed in future research aiming at specific applications of EOs in food products.

Harmonic motion imaging (HMI) is an ultrasound-based elasticity imaging technique that utilizes oscillatory acoustic radiation force to estimate the mechanical properties of tissues, as well as monitor high-intensity focused ultrasound (HIFU) treatment. Conventionally, in HMI, a focused ultrasound (FUS) transducer generates oscillatory tissue displacements, and an imaging transducer acquires channel data for displacement estimation, with each transducer being driven with a separate system. The fixed position of the FUS focal spot requires mechanical translation of the transducers, which can be a time-consuming and challenging procedure. In this study, we develop and characterize a new HMI system with a multi-element FUS transducer with the capability of electronic focal steering of ±5 mm and ±2 mm from the geometric focus in the axial and lateral directions, respectively. A pulse sequence was developed to drive both the FUS and imaging transducers using a single ultrasound data acquisition (DAQ) system. The setup was validated on a tissue-mimicking phantom with embedded inclusions. Integrating beam steering with the mechanical translation of the transducers resulted in a consistent high contrast to noise ratio (CNR) for the inclusions with Young's moduli of 22 and 44 kPa within a 5-kPa background while the data acquisition speed is increased by 4.5-5.2-fold compared to the case when only mechanical movements were applied. The feasibility of simultaneous generation of multiple foci and tracking the induced displacements is demonstrated in phantoms for applications where imaging or treatment of a larger region is needed. Moreover, preliminary feasibility is shown in a human subject with a breast tumor, where the mean HMI displacement within the tumor was about 4 times lower than that within perilesional tissues. The proposed HMI system facilitates data acquisition in terms of flexibility and speed and can be potentially used in the clinic for breast cancer imaging and treatment.

An emerging approach with potential in improving the treatment of neurodegenerative diseases and brain tumors is the use of focused ultrasound (FUS) to bypass the blood–brain barrier (BBB) in a non-invasive and localized manner. A large body of pre-clinical work has paved the way for the gradual clinical implementation of FUS-induced BBB opening. Even though the safety profile of FUS treatments in rodents has been extensively studied, the histological and behavioral effects of clinically relevant BBB opening in large animals are relatively understudied. Here, we examine the histological and behavioral safety profile following localized BBB opening in non-human primates (NHPs), using a neuronavigation-guided clinical system prototype. We show that FUS treatment triggers a short-lived immune response within the targeted region without exacerbating the touch accuracy or reaction time in visual-motor cognitive tasks. Our experiments were designed using a multiple-case-study approach, in order to maximize the acquired data and support translation of the FUS system into human studies. Four NHPs underwent a single session of FUS-mediated BBB opening in the prefrontal cortex. Two NHPs were treated bilaterally at different pressures, sacrificed on day 2 and 18 post-FUS, respectively, and their brains were histologically processed. In separate experiments, two NHPs that were earlier trained in a behavioral task were exposed to FUS unilaterally, and their performance was tracked for at least 3 weeks after BBB opening. An increased microglia density around blood vessels was detected on day 2, but was resolved by day 18. We also detected signs of enhanced immature neuron presence within areas that underwent BBB opening, compared to regions with an intact BBB, confirming previous rodent studies. Logistic regression analysis showed that the NHP cognitive performance did not deteriorate following BBB opening. These preliminary results demonstrate that neuronavigation-guided FUS with a single-element transducer is a non-invasive method capable of reversibly opening the BBB, without substantial histological or behavioral impact in an animal model closely resembling humans. Future work should confirm the observations of this multiple-case-study work across animals, species and tasks.

Focused ultrasound (FUS)-based viscoelastic imaging techniques using high frame rate (HFR) ultrasound to track tissue displacement can be used for mechanistic monitoring of FUS neuromodulation. However, a majority of techniques avoid imaging during the active push transmit (interleaved or postpush acquisitions) to mitigate ultrasound interference, which leads to missing temporal information of ultrasound effects when FUS is being applied. Furthermore, critical for clinical translation, use of both axial steering and real-time (1 s) capabilities for optimizing acoustic parameters for tissue engagement are largely missing. In this study, we describe a method of noninterleaved, single Vantage imaging displacement within an active FUS push with simultaneous axial steering and real-time capabilities using a single ultrasound acquisition machine. Results show that the pulse sequence can track micron-sized displacements using frame rates determined by the calculated time-of-flight (TOF), without interleaving the FUS pulses and imaging acquisition. Decimation by 3-7 frames increases signal-to-noise ratio (SNR) by 15.09±7.03 dB. Benchmarking tests of CUDA-optimized code show increase in processing speed of 35- and 300-fold in comparison with MATLAB parallel processing GPU and CPU functions, respectively, and we can estimate displacement from steered push beams ±10 mm from the geometric focus. Preliminary validation of displacement imaging in humans shows that the same driving pressures led to variable nerve engagement, demonstrating important feedback to improve transducer coupling, FUS incident angle, and targeting. Regarding the use of our technique for neuromodulation, we found that FUS altered thermal perception of thermal pain by 0.9643 units of pain ratings in a single trial. Additionally, 5 [Formula: see text] of nerve displacement was shown in on-target versus off-target sonications. The initial feasibility in healthy volunteers warrants further study for potential clinical translation of FUS for pain suppression.

Non-invasive diagnosis of breast cancer is still challenging due to the low specificity of the imaging modalities that calls for unnecessary biopsies. The diagnostic accuracy can be improved by assessing the breast tissue mechanical properties associated with pathological changes. Harmonic motion imaging (HMI) is an elasticity imaging technique that uses acoustic radiation force to evaluate the localized mechanical properties of the underlying tissue. Herein, we studied the in vivo feasibility of a clinical HMI system to differentiate breast tumors based on their relative HMI displacements, in human subjects. We performed HMI scans in 10 female subjects with breast masses: five benign and five malignant masses. Results revealed that both benign and malignant masses were stiffer than the surrounding tissues. However, malignant tumors underwent lower mean HMI displacement (1.1 ± 0.5 µm) compared to benign tumors (3.6 ± 1.5 µm) and the adjacent non-cancerous tissue (6.4 ± 2.5 µm), which allowed to differentiate between tumor types. Additionally, the excised breast specimens of the same patients (n = 5) were imaged post-surgically, where there was an excellent agreement between the in vivo and ex vivo findings, confirmed with histology. Higher displacement contrast between cancerous and non-cancerous tissue was found ex vivo, potentially due to the lower nonlinearity in the elastic properties of ex vivo tissue. This preliminary study lays the foundation for the potential complementary application of HMI in clinical practice in conjunction with the B-mode to classify suspicious breast masses.

Temperature measurements with thin thermocouples embedded in ultrasound fields are strongly subjected to a viscous heating artifact (VHA). The artifact contribution decays over time; therefore, it can be minimized at late temperature readings. However, previous studies have failed to demonstrate a rigorous method for determining the optimal time point at which the artifact contribution is negligible. In this study, we present an iterative processing method based on successive curve fittings using an artifact-independent model. The fitting starting point moves at each iteration until the maximum $R^{2}$ indicates where the viscous heating is minimum. A solution of the bioheat transfer equation is used to account for blood perfusion, thus enabling in vivo measurements. Three T-type thermocouples with different diameters and sensitivities were assessed in an excised canine liver and in the mouse brain in vivo . We found that the artifact constitutes up to 81% ± 5% of wire thermocouple readings. The best-fit time varied in the liver samples ( $n = 3$ ) from 0 to 3.335 ± 0.979 s and in the mouse brain ( $n = 5$ ) from 0 to 0.498 ± 0.457 s at variable experimental conditions, which clearly demonstrates the need of the method for finding the appropriate starting time point of the fit. This study introduces a statistical method to determine the best time to fit a curve that can back-estimate temperature in tissues under ultrasound exposure using thermocouples. This method allows temperature evaluation in vivo and in vitro during a validation and safety assessment of a wide range of therapeutic and diagnostic ultrasound modalities.

Harmonic Motion Imaging (HMI) is an acoustic radiation-force (RF) based elasticity imaging technique which can be used to monitor focused ultrasound (FUS) induced ablation without interruption. Our group has previously demonstrated frequency domain filtering in removing FUS interference from imaging data. However, FUS interference becomes more pronounced at increased intensities and durations, and various imaging and tracking transducer configurations may cause an overlap in frequency spectra between the FUS and imaging pulse, making frequency domain filtering unsuitable. FUS-net, a CNN-based UNET autoencoder developed by our group, was previously shown to be able to reduce FUS artifacts in RF data acquired with single acoustic radiation force (ARF) pulses with a duration of 1 to 2 ms. In this study, FUS-net was applied to reduce FUS artifacts in an RF dataset acquired during HMI, with continuous wave oscillating pulses for a duration of 6s. The FUS-net model was trained and tested on beamformed RF data acquired from an in vivo breast cancer mouse model (N=3) and ex vivo human fibroadenoma breast tissue (N=1). Notch filtered beamformed RF data was used as ground truth. Displacement estimated from FUS-net processed data was compared to displacement estimated from notch filtered RF data. We showed less noise in the focal area of HMI displacement maps in the FUS-net filtered dataset as compared with frequency-based filtering, with a median coefficient of variation of 0.7 and 0.2 in displacement calculated from notch filtered RF data and FUS-net filtered data respectively.

Focused ultrasound (FUS) has been used to non-invasively elicit or inhibit motor neuronal activity in the mouse peripheral nervous system in vivo. However, less is known about whether FUS elicits immune system responses associated with peripheral sensory neuronal activity. In this study, we sought to determine that non-invasive ultrasound image-guided FUS can elicit the neurogenic axon reflex of peripheral nerves in the mouse sciatic nerve. The local vasodilation in the plantar view of the hind paw detected with a high-resolution laser Doppler imager indicated neurogenic flare responses after FUS stimulation. The effects of FUS were compared with control groups, where a distinct pattern of blood flow changes was observed only in FUS-elicited neurogenic flare responses. The findings indicate that image-guided FUS elicits local axon reflexes in vivo with a high degree of specificity and penetration depth.

Ultrasound attenuation through soft tissues can produce an acoustic radiation force (ARF) and heating. The ARF-induced displacements and temperature evaluations can reveal tissue properties and provide insights into focused ultrasound (FUS) bio-effects. In this study, we describe an interleaving pulse sequence tested in a tissue-mimicking phantom that alternates FUS and plane-wave imaging pulses at a 1 kHz frame rate. The FUS is amplitude modulated, enabling the simultaneous evaluation of tissue-mimicking phantom displacement using harmonic motion imaging (HMI) and temperature rise using thermal strain imaging (TSI). The parameters were varied with a spatial peak temporal average acoustic intensity (I(spta)) ranging from 1.5 to 311 W.cm(−2), mechanical index (MI) from 0.43 to 4.0, and total energy (E) from 0.24 to 83 J.cm(−2). The HMI and TSI processing could estimate displacement and temperature independently for temperatures below 1.80°C and displacements up to ~117 μm (I(spta)

International audience; The blood-brain barrier is the primary obstacle to efficient intracerebral drug delivery. Focused ultrasound, in conjunction with microbubbles, is a targeted and non-invasive way to disrupt the blood-brain barrier. Many commercially available ultrasound contrast agents and agents specifically designed for therapeutic purposes have been investigated in ultrasound-mediated blood-brain barrier opening studies. The new generation of sono-sensitive agents, such as liquid-core droplets, can also potentially disrupt the blood-brain barrier after their ultrasound-induced vaporization. In this review, we describe the different compositions of agents used for ultrasound-mediated blood-brain barrier opening in recent studies, and we discuss the challenges of the past five years related to the optimal formulation of agents.

International audience; Since its discovery in 2001, the interest in the low-intensity focused ultrasound (FUS)-mediated blood-brain barrier (BBB) disruption to deliver genes and drugs to brain tissue has increased steadily. Increasingly sophisticated sonication protocols and dedicated hardware are being developed to efficiently and safely permeabilize the BBB, and novel magnetic resonance (MR)-based technologies have been designed to guide FUS-induced BBB opening protocols. MR imaging (MRI) allows not only to more precisely target brain regions and evaluate the outcome of sonication in terms of enhanced BBB permeability but also to control the effects of ultrasound on brain structure and function. This review summarizes the state of the art in current MRI hardware and methods used in BBB opening protocols both in pre-clinical and clinical settings.

Harmonic motion imaging (HMI) is an elasticity imaging method that employs an amplitude modulated (AM) acoustic radiation force to generate oscillations within the tissue. Recently, the capability of HMI in characterizing tumors with different geometries and pathologies was demonstrated in murine and human subjects using an AM frequency of 25 Hz. However, there is still a need to optimize the technique to reconstruct small lesions and improve image contrast. In this study, we investigated the role of the AM frequency in HMI and how it can detect and characterize inclusions with different sizes and stiffnesses in experimental tissue-mimicking phantoms.

Current treatments for neuropathic pain, such as pharmaceuticals and electrical stimulation, have large trade-offs in specificity and the need for surgical interventions. Moreover, these treatments have variable effectiveness and may only work in select populations of patients. Here we explore the use of focused ultrasound (FUS) for mitigating pain in healthy subjects. Nociceptive pain was induced using a custom heating probe and FUS was applied upstream to the median nerve. Our results show that pain ratings were reduced by a maximum of 1.4 units of pain from FUS vs sham stimuli. Moreover, a minimum amount of displacement was observed for pain the reduction. These findings lay the groundwork for reduction of pain using FUS neuromodulation.

Focused ultrasound (FUS) is an emerging technique for neuromodulation due to its noninvasive application and high depth penetration. Recent studies have reported success in modulation of brain circuits, peripheral nerves, ion channels, and organ structures. In particular, neuromodulation of peripheral nerves and the underlying mechanisms remain comparatively unexplored in vivo . Lack of methodologies for FUS targeting and monitoring impede further research in in vivo studies. Thus, we developed a method that non-invasively measures nerve engagement, via tissue displacement, during FUS neuromodulation of in vivo nerves using simultaneous high frame-rate ultrasound imaging. Using this system, we can validate, in real-time, FUS targeting of the nerve and characterize subsequent compound muscle action potentials (CMAPs) elicited from sciatic nerve activation in mice using 0.5 to 5 ms pulse durations and 22 - 28 MPa peak positive stimulus pressures at 4 MHz. Interestingly, successful motor excitation from FUS neuromodulation required a minimum interframe nerve displacement of $18~\mu m$ without any displacement incurred at the skin or muscle levels. Moreover, CMAPs detected in mice monotonically increased with interframe nerve displacements within the range of 18 to $300~\mu m$ . Thus, correlation between nerve displacement and motor activation constitutes strong evidence FUS neuromodulation is driven by a mechanical effect given that tissue deflection is a result of highly focused acoustic radiation force.

Ultrasound can modulate activity in the central nervous system, including the induction of motor responses in rodents. Recent studies investigating ultrasound-induced motor movements have described mostly bilateral limb responses, but quantitative evaluations have failed to reveal lateralization or differences in response characteristics between separate limbs or how specific brain targets dictate distinct limb responses. This study uses high-resolution focused ultrasound (FUS) to elicit motor responses in anesthetized mice in vivo and four-limb electromyography (EMG) to evaluate the latency, duration and power of paired motor responses (n = 1768). The results indicate that FUS generates target-specific differences in electromyographic characteristics and that brain targets separated by as little as 1 mm can modulate the responses in individual limbs differentially. Exploiting these differences may provide a tool for quantifying the susceptibility of underlying neural volumes to FUS, understanding the functioning of the targeted neuroanatomy and aiding in mechanistic studies of this non-invasive neuromodulation technique.

Made available in DSpace on 2018-11-26T17:42:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-10-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Our study aimed to evaluate crack cocaine effects in different life stages of the marine mussel Perna perm. For this purpose, fertilization rate, embryo-larval development, lysosomal membrane stability and DNA strand breaks were assessed. Effect concentrations in gametes and in larval development were found after 1 h (IC50 = 23.53 mg.L-1) and 48 h (IC50 = 16.31 mg.L-1),respectively. The highest tested concentration showing no acute toxicity (NOEC) was 10 mg.L-1, while the lowest observed effect concentration (LOEC) was 20 mg.L-1. NOEC concerning embryo-larval development was 0.625 mg.L-1, while the LOEC was 1.25 mg.L-1. Cyto-genotoxic effects were evidenced in mussels exposed to crack cocaine concentrations ranging from 5 to 500 mu g.L-1. Our results report the first data on effects of an illicit drug to marine organisms and should encourage further ecotoxicological studies of these contaminants of emerging concern in coastal ecosystems. Univ Fed Sao Paulo, Dept Ciencias Mar, Rua Dr Carvalho Mendonga 144, BR-11070102 Santos, Brazil Univ Santa Cecilia, Lab Ecotoxicol, Rua Oswaldo Cruz 266, BR-11045907 Santos, Brazil CIETEC IPEN, CEMSA Ctr Espectrometria Massas Aplicada, Ave Prof Lineu Prestes 2242,Salas 112 & 113, BR-05508000 Sao Paulo, Brazil Univ Estadual Paulista, Campus Litoral Paulista, Inst Biociencias, Infante Dom Henrique S-N, BR-11330900 Sao Vicente, Brazil Univ Fed Sao Paulo, Dept Biociencias, Av Ana Costa 95, BR-11060001 Santos, Brazil Univ Estadual Paulista, Campus Litoral Paulista, Inst Biociencias, Infante Dom Henrique S-N, BR-11330900 Sao Vicente, Brazil FAPESP: 2015/17329-0 CNPq: 402931/2015-7

Chronic pain can be alleviated using paresthesia caused by electrical stimulation of peripheral nerves. However, the implantation of electrodes is necessary to increase the specificity and efficacy of the treatment. Alternatively, focused ultrasound (FUS) can noninvasively and selectively modulate nerve function, which could potentially be an alternative to inducing paresthesia. Here, we show initial feasibility of FUS stimulation in the peripheral nerve of healthy human subjects. Somatosensory evoked potential (SSEP) elicited by electrical stimulation of the median nerve is demonstrated to decrease in amplitude while FUS is concurrently applied on the median nerve. The suppression of SSEP signals indicates the modulation of sensory signaling to the brain, which can potentially be used to reduce pain.

Focused ultrasound (FUS), being non-invasive and non-ionizing, has been postulated as a possible therapeutic for peripheral nerve modulation. Recently, the ability to use high intensity, short pulse FUS has been demonstrated in rodents. In order to adapt this technology for clinical translation, a technique for real-time imaging and validation of FUS neuromodulation is needed. In this study, we developed a technique to image FUS using a two probes, connected to a single Vantage research ultrasound machine for real-time elastography during FUS delivery without interleaved transmits. Using a custom transmit sequence, we can image displacements around 1 μm. Validation of FUS delivery to the median nerve was performed in humans (n = 5). This technique allows for greater accuracy and confidence in applying neuromodulation to human peripheral nerves.

Focused ultrasound (FUS)-mediated blood-brain barrier (BBB) opening is currently being investigated in clinical trials. Here, we describe a portable clinical system with a therapeutic transducer suitable for humans, which eliminates the need for in-line magnetic resonance imaging (MRI) guidance. A neuronavigation-guided 0.25-MHz single-element FUS transducer was developed for non-invasive clinical BBB opening. Numerical simulations and experiments were performed to determine the characteristics of the FUS beam within a human skull. We also validated the feasibility of BBB opening obtained with this system in two non-human primates using U.S. Food and Drug Administration (FDA)-approved treatment parameters. Ultrasound propagation through a human skull fragment caused 44.4 ± 1% pressure attenuation at a normal incidence angle, while the focal size decreased by 3.3 ± 1.4% and 3.9 ± 1.8% along the lateral and axial dimension, respectively. Measured lateral and axial shifts were 0.5 ± 0.4 mm and 2.1 ± 1.1 mm, while simulated shifts were 0.1 ± 0.2 mm and 6.1 ± 2.4 mm, respectively. A 1.5-MHz passive cavitation detector transcranially detected cavitation signals of Definity microbubbles flowing through a vessel-mimicking phantom. T1-weighted MRI confirmed a 153 ± 5.5 mm3 BBB opening in two non-human primates at a mechanical index of 0.4, using Definity microbubbles at the FDA-approved dose for imaging applications, without edema or hemorrhage. In conclusion, we developed a portable system for non-invasive BBB opening in humans, which can be achieved at clinically relevant ultrasound exposures without the need for in-line MRI guidance. The proposed FUS system may accelerate the adoption of non-invasive FUS-mediated therapies due to its fast application, low cost and portability.

Measuring temperature during focused ultrasound (FUS) procedures is critical for characterization, calibration, and monitoring to ultimately ensure safety and efficacy. Despite the low cost and the high spatial and temporal resolutions of temperature measurements using thermocouples, the viscous heating (VH) artifact at the thermocouple-tissue interface requires reading corrections for correct thermometric analysis. In this study, a simulation pipeline is proposed to correct the VH artifact arising from temperature measurements using thermocouples in FUS fields. The numerical model consists of simulating a primary source of heating due to ultrasound absorption and a secondary source of heating from viscous forces generated by the thermocouple in the FUS field. Our numerical validation found that up to 90% of the measured temperature rise was due to VH effects. Experimental temperature measurements were performed using thermocouples embedded in fresh chicken breast samples. Temperature corrections were demonstrated for single high-intensity FUS pulses at 3.1 MHz and for multiple pulses (3.1 MHz, 100 Hz, and 500 Hz pulse repetition frequency). The VH accumulated during sonications and produced a temperature increase of 3.1 °C and 15.3 °C for the single and multiple pulse sequences, respectively. The methodology presented here enables the decoupling of the temperature increase generated by absorption and VH. Thus, more reliable temperature measurements can be extracted from thermocouple measurements by correcting for VH.

The blood-brain barrier (BBB) prevents most drugs from gaining access to the brain parenchyma, which is a recognized impediment to the treatment of neurodegenerative disorders like Parkinson's disease (PD). Focused ultrasound (FUS), in conjunction with systemically administered microbubbles, opens the BBB locally, reversibly and non-invasively. Herein, we show that neither FUS applied over both the striatum and the ventral midbrain, without neurotrophic factors, nor intravenous administration of neurotrophic factors (either through protein or gene delivery) without FUS, ameliorates the damage to the nigrostriatal dopaminergic pathway in the sub-acute MPTP mouse model of early-stage PD. Conversely, the combination of FUS and intravenous neurotrophic (protein or gene) delivery attenuates the damage to the nigrostriatal dopaminergic pathway, by allowing the entry of these agents into the brain parenchyma. Our findings provide evidence that the application of FUS at the early stages of PD facilitates critical neurotrophic delivery that can curb the rapid progression of neurodegeneration while improving the neuronal function, seemingly opening new therapeutic avenues for the early treatment of diseases of the central nervous system.

Purpose: Ultrasound neuromodulation is a promising noninvasive technique for controlling neural activity. Previous small animal studies suffered from low targeting specificity because of the low ultrasound frequencies (

Objective. Focused ultrasound (FUS) has recently been demonstrated capable of exciting motor neuronal activity. However, comprehensive understanding of elucidated excitatory and inhibitory effects is required to better assess FUS-mediated modulation. In this study, we demonstrate that image-guided FUS can selectively modulate motor neuron activity in the mouse sciatic nerve in vivo and attribute motor responses to thermal effects. Approach. FUS was applied on the sciatic nerve of anesthetized mice in vivo through the intact skin and muscle using ultrasound imaging for targeting. Both excitatory and inhibitory effects were recorded using electromyography (EMG) along with muscle response of the hind limb. The effects of FUS modulation vs heating by invasive alternative heating source (AHS) on electrically evoked EMG responses in the sciatic nerve in vivo were also investigated. The safety and reversibility of the technique were validated using histology and EMG recovery. Main results. The FUS was capable of eliciting motor neuronal activity comparable to electrical stimulation, and facilitating motor neuronal response on electrically evoked potentials with temperature elevation up to 11.5 ± 0.3 oC (PRF ≤ 40 Hz). On the other hand, FUS-induced temperature elevations above 15.1 ± 1.6 oC (PRF ≥ 100 Hz) resulted in the suppression of electrically-evoked motor neuronal activity along with a decrease in EMG latency and area under the curve (AUC), which was validated against the invasive AHS with temperature elevation of 18.1 ± 8.5 oC instead of FUS modulation. Histological findings along with EMG responses after FUS modulation demonstrated a reversible or irreversible modulation. Significance. The findings reported herein indicate that image-guided FUS (PRF ≤ 100 Hz) induces safe and controllable modulation of involuntarily evoked motor neuron activity in vivo.

Conventional treatments of neuropathic pain are commonly invasive or non-localized. Focused ultrasound (FUS) is a promising neuromodulation technique that has been shown effective in various animal models. There have been numerous advances in the field of ultrasound neuromodulation with the technology already being applied to humans without a clear understanding of the underlying mechanism. Here, we present a method capable of targeting and monitoring of focused ultrasound (FUS) neuromodulation of the mouse sciatic nerve using high frame-rate displacement and cavitation imaging. Our technique is capable of detecting micron displacements and cavitation activity at the focus. Displacement and cavitation were measured with excitation of the sciatic nerve, indicating that radiation force and cavitation play in parts of the underlying mechanism. Taken together, our imaging technique is a powerful in vivo tool for real-time targeting of deep structures and investigation of the FUS neuromodulation mechanism.

Focused ultrasound (FUS) has demonstrated the ability to modulate nervous system activity in animals. Recently, higher frequency focused transducers have been used to successfully elicit motor responses in mice in vivo. Despite this success, quantitative analyses of the temporal and magnitude-related characteristics of FUS elicited motor responses measured with electromyography (EMG) and the spatial specificity of those responses have been poorly described. In this study, we use a focused transducer with high spatial resolution (1mm lateral focal diameter) and EMG to evaluate six quantitative EMG response characteristics. Results demonstrate that these responses are highly specific to the brain volume acted upon by the FUS

Brain diseases including neurological disorders and tumors remain under treated due to the challenge to access the brain, and blood-brain barrier (BBB) restricting drug delivery which, also profoundly limits the development of pharmacological treatment. Focused ultrasound (FUS) with microbubbles is the sole method to open the BBB noninvasively, locally, and transiently and facilitate drug delivery, while translation to the clinic is challenging due to long procedure, targeting limitations, or invasiveness of current systems. In order to provide rapid, flexible yet precise applications, we have designed a noninvasive FUS and monitoring system with the protocol tested in monkeys (from in silico preplanning and simulation, real-time targeting and acoustic mapping, to post-treatment assessment). With a short procedure (30 min) similar to current clinical imaging duration or radiation therapy, the achieved targeting (both cerebral cortex and subcortical structures) and monitoring accuracy was close to the predicted 2-mm lower limit. This system would enable rapid clinical transcranial FUS applications outside of the MRI system without a stereotactic frame, thereby benefiting patients especially in the elderly population.

Focused ultrasound (FUS) can noninvasively and reversibly modulate brain activity. Observed motor activity or behavioral changes are commonly used to infer neuromodulatory effects. Changes in autonomic nervous system regulation such as heart and respiratory function can potentially be used for studying the effects of FUS neuromodulation that do not produce outwardly observable motor or behavioral activity. In this study, low pressure (850 kPa), long duration (120 s) continuous-wave (CW) FUS at 2 MHz was targeted such that the focus spanned the visual cortex, hippocampus, and thalamus. These parameters were shown to reversibly depress heart rate in in vivo mice anesthetized with sodium pentobarbital by an average of 8.1 ± 3.7%. Following stimulus offset, heart rate either increased or varied in trend. Higher pressure (2 MPa), short duration (0.3 s) pulses at the same frequency resulted in either small, transient increases in heart rate or no change. Thermocouple measurements show the peak temperature elevation in the dura to be approximately 2 °C. Thermal simulations predict a peak temperature increase in the brain of 2.3 °C. These results indicate that CW FUS can alter autonomic nervous system regulation through very low heating and show that cardiorespiratory responses can be altered as a result of FUS neuromodulation.

Chirp- and random-based coded excitation methods have been proposed to reduce standing wave formation and improve focusing of transcranial ultrasound. However, no clear evidence has been shown to support the benefits of these ultrasonic excitation sequences in vivo. This study evaluates the chirp and periodic selection of random frequency (PSRF) coded-excitation methods for opening the blood-brain barrier (BBB) in mice. Three groups of mice (n=15) were injected with polydisperse microbubbles and sonicated in the caudate putamen using the chirp/PSRF coded (bandwidth: 1.5-1.9 MHz, peak negative pressure: 0.52 MPa, duration: 30 s) or standard ultrasound (frequency: 1.5 MHz, pressure: 0.52 MPa, burst duration: 20 ms, duration: 5 min) sequences. T1-weighted contrast-enhanced MRI scans were performed to quantitatively analyze focused ultrasound induced BBB opening. The mean opening volumes evaluated from the MRI were 9.38±5.71 mm3, 8.91±3.91 mm3 and 35.47 ± 5.10 mm3 for the chirp, random and regular sonications, respectively. The mean cavitation levels were 55.40±28.43 V.s, 63.87±29.97 V.s and 356.52±257.15 V.s for the chirp, random and regular sonications, respectively. The chirp and PSRF coded pulsing sequences improved the BBB opening localization by inducing lower cavitation levels and smaller opening volumes compared to results of the regular sonication technique. Larger bandwidths were associated with more focused targeting but were limited by the frequency response of the transducer, the skull attenuation and the microbubbles optimal frequency range. The coded methods could therefore facilitate highly localized drug delivery as well as benefit other transcranial ultrasound techniques that use higher pressure levels and higher precision to induce the necessary bioeffects in a brain region while avoiding damage to the surrounding healthy tissue.

Background: Vibro-acoustography (VA) uses two co-focused ultrasound beams with slightly different frequencies. The beams interact and generate a low-frequency focus to excite an object. Methods: A two-element confocal ultrasound transducer with central frequency at 3.2 MHz was used to generate the low-frequency excitation (30 kHz) and the response of the bone to that excitation was acquired by a dedicated hydrophone. The face of the confocal transducer was positioned parallel to the surface of the bone at a focal length of 7 cm. The hydrophone was fixed to the side of the transducer, out of the path of the ultrasonic beam. Results: The resulting image clearly showed the bone fracture with resolution of 0.25 mm and high contrast with well-defined borders. Conclusions: In this paper, we present preliminary results of VA imaging of bone surface and of bone fracture using an experimental set-up. Our results encourage future studies using VA to evaluate bone fractures.

Despite the progress of focused ultrasound (FUS)-mediated blood-brain barrier (BBB) disruption, neuro-inflammatory responses and the high variability of the FUS transmission through the human skull make the control of the acoustic parameters challenging. In this study, we developed a high-field (7-T) magnetic resonance (MR)-guided FUS system with a feedback control based on passive cavitation detection (PCD) to explore BBB opening in non-human primates (NHP). The sonication parameters were: 2 min duration, 500-kHz frequency, pulse length of 10 ms, and pulse repetition frequency of 5 Hz. T1-weighted MR images acquired every 5 min revealed a maximum contrast enhancement of 67% ± 15% relative to muscle after 30 min of sonication. Safe sonications were achieved in the 3 sessions using real-time PCD-based feedback control of the acoustic pressure. The high resolution anatomical images and the high temporal/spatial resolution of contrast agent diffusion provide a unique tool for studying the mechanisms of BBB disruption and drug delivery in NHP. Furthermore, the PCD-based feedback control allows repeatable safe sonication regardless of the variation of skull attenuation, allowing comparisons across animals and experimental sessions.

In vibro-acoustography imaging systems, two ultrasound beams of distinct frequencies are employed to form an image of biological tissue at the difference-frequency. Three mechanisms contribute to the difference-frequency pressure, namely induced acoustic emission by a time-modulated radiation force, parametric array signal due to the superposition the beams along the propagation direction, and interaction of sound-with-sound effects. We analyze the strength of parametric array signal generated by a vibro-acoustography system composed of a two-element confocal transducer driven by two sinusoidal signals with center frequency 3.2 MHz. A 1-mm diameter tungsten sphere, placed at the transducer’s focus, is used as the target object. We measure the difference-frequency pressure in water at room temperature with a calibrated hydrophone. The measurements are taken along the beam’s axis in the farfield. In this configuration, the difference-frequency signal is mostly due to the parametric array phenomenon. Additionally, the acoustic emission and interaction of sound-with-sound signal levels are theoretically estimated. They are, respectively, 33 and 20 dB below the parametric array signal.

OBJECTIVES: This paper proposes imaging with 3-dimensional vibroacoustography for postoperatively assessing the uncovered cup area after total hip arthroplasty as a quantitative criterion to evaluate implant fixation. METHODS: A phantom with a bone-like structure covered by a tissue-mimicking material was used to simulate a total hip arthroplasty case. Vibroacoustography images of the uncovered cup region were generated using a two-element confocal ultrasound transducer and a hydrophone inside a water tank. Topological correction based on the geometry of the implant was performed to generate a 3-dimensional representation of the vibroacoustography image and to accurately evaluate the surface. The 3-dimensional area obtained by the vibroacoustography approach was compared to the area evaluated by a 3-dimensional motion capture system. RESULTS: The vibroacoustography technique provided high-resolution, high-contrast, and speckle-free images with less sensitivity to the beam incidence. Using a 3-dimensional-topology correction of the image, we accurately estimated the uncovered area of the implant with a relative error of 8.1% in comparison with the motion capture system measurements. CONCLUSION: Measurement of the cup coverage after total hip arthroplasty has not been well established; however, the covered surface area of the acetabular component is one of the most important prognostic factors. The preliminary results of this study show that vibroacoustography is a 3-dimensional approach that can be used to postoperatively evaluate total hip arthroplasty. The favorable results also provide an impetus for exploring vibroacoustography in other bone or implant surface imaging applications.

Lipases are enzymes produced from innumerous microorganisms, plants and animal cells. They catalyze reactions of different lipid sources. The Geotrichum fungi are good producers of lipases with high hydrolytic activity and specificity for unsaturated fatty acids. A great number of studies have reported the importance of lipase from this genus and described important fermentation parameters for the enzyme production, such as nutrients, temperature, pH, inoculum, time of fermentation and others. Furthermore, different strategies have been used to purify and immobilize lipases from Geotrichum and innumerous applications are cited in different processes as polyunsaturated fatty acids enrichment, hydrolysis and esterification of fat and oils, synthesis of aromas, biodiesel, and many others. This review highlights fundamental aspects of the production, purification, characterization, immobilization, and the applications of lipases produced by the genus Geotrichum.

In this work, we present a numerical study of the use of reconfigurable arrays (RCA) for vibro-acoustography (VA) beam formation. A parametric study of the aperture selection, number of channels, number of elements, focal distance, and steering parameters is presented in order to show the feasibility and evaluate the performance of VA imaging based on RCA. The transducer aperture was based on two concentric arrays driven by two continuous-wave or toneburst signals at slightly different frequencies. The mathematical model considers a homogeneous, isotropic, inviscid medium. The point-spread function of the system is calculated based on angular spectrum methods using the Fresnel approximation for rectangular sources. Simulations considering arrays with 50 × 50 to 200 × 200 elements with number of channels varying in the range of 32 to 128 are evaluated to identify the best configuration for VA. Advantages of two dimensional and RCA arrays and aspects related to clinical importance of the RCA implementation in VA such as spatial resolution, image frame-rate, and commercial machine implementation are discussed. It is concluded that RCA transducers can produce spatial resolution similar to confocal transducers, steering is possible in elevation and azimuthal planes, and optimal settings for number of elements, number of channels, maximum steering, and focal distance are suggested for VA clinical application. Furthermore, an optimization for beam steering based on the channel assignment is proposed for balancing the contribution of the two waves in the steered focus.

A vibroacustografia (VA) é uma técnica de imagem de alta resolução lateral (

Beam distortions of focused ultrasound (FUS) caused by skull may compromise accurate targeting of transcranial therapeutic ultrasound applications. Although, the efficacy of the random and chirp modulations in improving targeting have been proven in simulations, ex-vivo and in phantom studies, many other parameters that can be observed in vivo are disregarded such as the heterogeneity of the soft tissue, the variability of the drug uptake and clearance among subjects. In this study, the capability of the chirp- and random-based coded ultrasonic excitation in improving the targeting is investigated using a FUS-mediated blood-brain barrier (BBB) opening protocol in mice. The coded ultrasonic excitation signals were generated with frequency bandwidth: 1.5–1.9 MHz, pressure: 0.52 MPa, and duration: 30 s. Fifteen mice were divided in three groups (n=5 each). One group was sonicated in the right caudate putamen with chirp-based signal (frequency varying linearly), the other group was sonicated with random-based coded signal (randomly varying frequency) and they were compared with a third group sonicated with standard mono-frequency ultrasound (1.5 MHz, 0.52 MPa, burst duration: 20 ms, total duration: 5 min). The mean BBB opening volumes assessed by contrast enhanced magnetic resonance imaging were 9.38 ± 5.71 mm3, 8.91 ± 3.91 mm3 and 35.47 ± 5.10 mm3 for the chirp, random and standard sonication, respectively. The mean cavitation levels assessed by passive cavitation detection were 55.40 ± 28.43 V.s, 63.87 ± 29.97 V.s and 356.52 ± 257.15 V.s for the same groups. The coded excitation methods improved the targeting precision, generating lower cavitation levels and more confined opening volumes than the conventional sonication. The coded excitation methods may thus enable more precise drug delivery and it may benefit other FUS applications that use higher-pressure levels and require precision to ablate or stimulate the targeted region.

Focused ultrasound (FUS) neuromodulation has been previously proposed as a promising technique to drive neuronal activity. Here, we explored motor- and cognitive-related brain regions of mice by targeting specific brain structures using FUS neuromodulation in the mega-Hz range under a specific type of anesthesia. Contralateral motor responses were observed showing successful target specificity of the FUS neuromodulation achieved with 1.9 MHz. Higher acoustic pressures increased the success rate from 20% (at the threshold, 1.45 MPa) to 70% (1.79 MPa). The estimated latency measured by electromyography was 266 ± 37 ms. Pupil dilation was observed when neuromodulating regions in the brain covering the superior colliculus and other anxiety-related structures such as hippocampus and locus coeruleus. This study demonstrated the capability of FUS to modulate target specific regions in the brain including pupil dilation induced by FUS for the first time. Furthermore, evoked responses by cognitive regions demonstrated the capability of FUS to modulate deeper structures in the brain.

Embryonic and fetal mortality reduce reproductive performance of lactating dairy cows. The objectives of this study were to reduce pregnancy loss by administering a deslorelin implant (GnRH agonist) during the late embryonic period, to reduce follicular growth, induce accessory corpora lutea, and increase plasma progesterone concentrations. Lactating dairy cows received an implant containing 2.1 mg of deslorelin (Deslorelin group; n = 89) or no treatment (Control group; n = 92) on Day 27 of pregnancy. Pregnancy, ovarian structures and plasma progesterone concentrations were determined on Days 27 and 45, and pregnancy was re-confirmed on Day 90. On Day 45, mean +/- S.E.M. numbers of class 2 (6-9 mm; 0.72+/-0.19) and class 3 (or = 10 mm; 0.86 +/- 0.12) follicles for cows in the Deslorelin group were lower (P0.01) than the numbers of class 2 (1.90 +/- 0.18) and class 3 (1.92 +/- 0.12) follicles for cows in the Control group. On Day 45, the number of accessory corpora lutea for cows in the Deslorelin group (1.80 +/- 0.07) were greater (P0.01) than for cows in the Control group (1.31 +/- 0.07). On Day 45, plasma progesterone concentration was increased (P0.01) for cows in the Deslorelin group (8.03 +/- 0.33 ng/mL) compared to cows in the Control group (6.40 +/- 0.31 ng/mL). Pregnancy losses did not differ between Days 27 and 45 and Days 45 and 90 for cows in the Control (15.2 and 11.0%, respectively) and Deslorelin groups (20.2 and 10.5%, respectively). However, in the Deslorelin group, pregnancy loss between Days 45 and 90 was lower (P0.05) for cows that formed an accessory CL (0%) compared to cows that did not form an accessory CL (16.1%).

The objective was to compare pregnancy rates to resynchronization and timed AI (TAI) protocols in lactating dairy cows that received GnRH at 23d and were diagnosed not pregnant at 30d after the pre-enrollment AI. Nonpregnant cows (624) at ultrasonography on day 30 (study day 0) were classified as diestrus (74.8%), metestrus (5.6%) and without a CL (19.5%). Cows in diestrus were assigned either to the GnRH group (PGF 2α on day 0, GnRH on day 2 and TAI 16h later, n = 238) or the estradiol cypionate (ECP) group (PGF 2α on day 0, ECP on day 1, and TAI 36h later, n = 229). Cows in metestrus were assigned to the Modified Heatsynch Group (GnRH on day 0, PGF 2α on day 7, ECP on day 8 and TAI on day 9, n = 35). Cows without a CL ( n = 122) were classified either as proestrus (10.6%), ovarian cysts (7.5%) or anestrus (1.4%), and assigned to factorial treatments (i.e., use of GnRH versus CIDR) to either the GnRH group (GnRH on day 0, PGF 2α on day 7, GnRH on day 9 and TAI 16h later, n = 28), the CIDR group (CIDR insert from days 0 to 7, PGF 2α on day 7, GnRH on day 9 and TAI 16h later, n = 34), the GnRH + CIDR group (GnRH on day 0, CIDR insert from days 0 to 7, PGF 2α on day 7, GnRH on day 9 and TAI 16h later, n = 32), and the control group (PGF 2α on day 7, GnRH on day 9 and TAI 16h later, n = 28). For cows without a CL, plasma P 4 concentrations were determined on days 0, 7, 10 and 17 and ovarian structures determined on days 0, 7 and 17. Pregnancy rates were evaluated at 30, 55 and 90d after the resynchronized AI. For cows in diestrus, there were no differences in pregnancy rates on days 30, 55 and 90 for cows in the GnRH (27.5, 26.5 and 24.2%) or ECP (29.1, 25.5 and 24.1%) groups. In addition, there were no differences in pregnancy losses between days 30 and 55 and 55 and 90 between the GnRH (7.0 and 8.6%) and ECP (9.8 and 5.4%) groups. For cows without a CL, GnRH on day 0 increased the proportion of cows with a CL on days 7 and 17 and plasma P 4 concentration on day 17 in cows with ovarian cysts but not for cows in proestrus. The CIDR insert increased pregnancy rate in cows with ovarian cysts but reduced pregnancy rate for cows in proestrus.