http://ieeexplore.ieee.org/iel5/5/31047/01444179.pdf

Fundamentals of acoustics

The objective of this review is to discuss the ultrasound-assisted extraction (UAE) of various compounds using clean, green solvents. We also outline fundamental mechanisms and factors associated with the design and the development of clean, green UAE systems. Growing consumer demands for greener alternatives and natural ingredients that do not involve toxic chemicals and the environmental and health risk associated with the use of chemical solvents have attracted the interest of industries to sustainable, non-toxic routes of extraction. UAE can benefit the chemical industry in multiple ways: • enhancing extraction yield; • enhancing aqueous extraction processes without using solvents; • providing the opportunity to use alternative clean and/or green solvents by improving their extraction performance; and, • enhancing extraction of heat-sensitive components under conditions that would otherwise have low or unacceptable yields.

Ultrasound: A clean, green extraction technology

Ultrasound treatment is an alternative affordable, effective and reproducible method for the improved recovery of bioactive compounds from various processing streams. The objective of this review is to discuss the impact of ultrasound-assisted extraction on the recovery of polyphenols, carotenoids and chlorophylls from vegetal and algae matters. Optimization strategies will need to focus on appropriate equipment design and configuration of ultrasonic components, and extrinsic and intrinsic control parameters including ultrasonic power, temperature and extraction time to maximize the yield and biological activity of the extract. Modeling strategies to characterize and optimize ultrasound processes are also be highlighted in the manuscript.

Clean recovery of antioxidant compounds from plant foods, by-products and algae assisted by ultrasounds processing. Modeling approaches to optimize processing conditions

Ultrasound is widely used for medical diagnosis and increasingly for therapeutic purposes. An understanding of the bio-effects of sonography is important for clinicians and scientists working in the field because permanent damage to biological tissues can occur at high levels of exposure. Here the underlying principles of thermal mechanisms and the physical interactions of ultrasound with biological tissues are reviewed. Adverse health effects derived from cellular studies, animal studies and clinical reports are reviewed to provide insight into the in vitro and in vivo bio-effects of ultrasound.

Mechanical and Biological Effects of Ultrasound: A Review of Present Knowledge.

Phenolic compounds are broadly represented in plant kingdom, and their occurrence in easily accessible low-cost sources like wastes from agri-food processing have led in the last decade to an increase of interest in their recovery and further exploitation. Indeed, most of these compounds are endowed with beneficial properties to human health (e.g., in the prevention of cancer and cardiovascular diseases), that may be largely ascribed to their potent antioxidant and scavenging activity against reactive oxygen species generated in settings of oxidative stress and responsible for the onset of several inflammatory and degenerative diseases. Apart from their use as food supplements or as additives in functional foods, natural phenolic compounds have become increasingly attractive also from a technological point of view, due to their possible exploitation in materials science. Several extraction methodologies have been reported for the recovery of phenolic compounds from agri-food wastes mostly based on the use of organic solvents such as methanol, ethanol, or acetone. However, there is an increasing need for green and sustainable approaches leading to phenolic-rich extracts with low environmental impact. This review addresses the most promising and innovative methodologies for the recovery of functional phenolic compounds from waste materials that have appeared in the recent literature. In particular, extraction procedures based on the use of green technologies (supercritical fluid, microwaves, ultrasounds) as well as of green solvents such as deep eutectic solvents (DES) are surveyed.

/pdf/bioactive-phenolic-compounds-from-agri-food-wastes-an-update-2mv78rlf9d.pdf

Bioactive Phenolic Compounds From Agri-Food Wastes: An Update on Green and Sustainable Extraction Methodologies.

Ultrasound can penetrate deep into tissues and interact with human tissue via thermal and mechanical mechanisms. The ability to focus an ultrasound beam and its energy onto millimeter-size targets was a significant milestone in the development of therapeutic applications of focused ultrasound. Focused ultrasound can be used as a non-invasive thermal ablation technique for tumor treatment and is being developed as an option to standard oncologic therapies. High-intensity focused ultrasound has now been used for clinical treatment of a variety of solid malignant tumors, including those in the pancreas, liver, kidney, bone, prostate, and breast, as well as uterine fibroids and soft-tissue sarcomas. Magnetic resonance imaging and Ultrasound imaging can be combined with high intensity focused ultrasound to provide real-time imaging during ablation. Magnetic resonance guided focused ultrasound represents a novel non-invasive method of treatment that may play an important role as an alternative to open neurosurgical procedures for treatment of a number of brain disorders. This paper briefly reviews the underlying principles of HIFU and presents current applications, outcomes, and complications after treatment. Recent applications of Focused ultrasound for tumor treatment, drug delivery, vessel occlusion, histotripsy, movement disorders, and vascular, oncologic, and psychiatric applications are reviewed, along with clinical challenges and potential future clinical applications of HIFU.

https://www.mdpi.com/2077-0383/9/2/460/pdf

An Introduction to High Intensity Focused Ultrasound: Systematic Review on Principles, Devices, and Clinical Applications.

Over the past decades, different techniques have been investigated for detecting microbubbles. The purpose of this work is to review the state-of-the-art of medical microbubble detection along with therapeutic, monitoring, and diagnostic applications. The presence of microbubbles in the human body can be induced either through cavitation or exogenous introduction of bubbles. One of the effects of ultrasound is cavitation, or microbubble formation and collapse. Cavitation produces high pressures and temperatures, and microbubble expansion and then collapse close to cells can lead to cellular damage or hemorrhage in biological tissues. Cavitation is, in most cases, an undesired event in clinical diagnostic imaging. Considering that cavitation microbubble formation is largely unpredictable, ultrasound imaging may present a rare or yet unknown risk, particularly to fetuses and embryos. Although most therapeutic ultrasound modalities work based on physical and thermal effects of cavitation, the safety of treatment strongly depends on accurate knowledge of the location of the cavitation inception point. Cavitation detection is an important factor with respect to improving the safety of ultrasound imaging and therapy. It is essential to recognize the existence and location of cavitation inception points. In addition, the use of encapsulated microbubbles as contrast agents for diagnostic imaging, as vehicles for local drug or gene delivery, and as tools for microbubble and ultrasound therapy in thrombolysis has increased the demand for an accurate deep tissue microbubble detection technique. There have been many attempts to detect cavitation bubbles, but each contains its own limitations. There is no doubt that continuous discoveries and developments in microbubble detection modalities will lead to safer and more efficient therapeutic and diagnostic equipment.

Ultrasound Cavitation/Microbubble Detection and Medical Applications

Ultrasound pretreatment of wheat dried distiller's grain (DDG) for extraction of phenolic compounds.

The observation of ultrasound generated cavitation bubbles deep in tissue is very difficult. The development of an imaging method capable of investigating cavitation bubbles in tissue would improve the efficiency and application of ultrasound in the clinic. Among the previous imaging modalities capable of detecting cavitation bubbles in vivo, the acoustic detection technique has the positive aspect of in vivo application. However the size of the initial cavitation bubble and the amplitude of the ultrasound that produced the cavitation bubbles, affect the timing and amplitude of the cavitation bubbles’ emissions. The spatial distribution of cavitation bubbles, driven by 0.8835 MHz therapeutic ultrasound system at output power of 14 Watt, was studied in water using a synchrotron X-ray imaging technique, Analyzer Based Imaging (ABI). The cavitation bubble distribution was investigated by repeated application of the ultrasound and imaging the water tank. The spatial frequency of the cavitation bubble pattern was evaluated by Fourier analysis. Acoustic cavitation was imaged at four different locations through the acoustic beam in water at a fixed power level. The pattern of cavitation bubbles in water was detected by synchrotron X-ray ABI. The spatial distribution of cavitation bubbles driven by the therapeutic ultrasound system was observed using ABI X-ray imaging technique. It was observed that the cavitation bubbles appeared in a periodic pattern. The calculated distance between intervals revealed that the distance of frequent cavitation lines (intervals) is one-half of the acoustic wave length consistent with standing waves. This set of experiments demonstrates the utility of synchrotron ABI for visualizing cavitation bubbles formed in water by clinical ultrasound systems working at high frequency and output powers as low as a therapeutic system.

/pdf/application-of-analyzer-based-x-ray-imaging-technique-for-26dpun8cdw.pdf

Zahra Izadifar

Papers

Mechanical and Biological Effects of Ultrasound: A Review of Present Knowledge.

An Introduction to High Intensity Focused Ultrasound: Systematic Review on Principles, Devices, and Clinical Applications.

Ultrasound Cavitation/Microbubble Detection and Medical Applications

Ultrasound pretreatment of wheat dried distiller's grain (DDG) for extraction of phenolic compounds.

Application of analyzer based X-ray imaging technique for detection of ultrasound induced cavitation bubbles from a physical therapy unit.