Provision of bone conduction hearing implants in England in adults and children: a review of Hospital Episode Statistics data 2012-2021

OBJECTIVE

Bone conduction hearing implants are a well-established method of hearing rehabilitation in children and adults. This study aimed to review any changes in provision in England.

METHODS

The total number of bone conduction hearing implantations performed was analysed from 2012 to 2021 utilising Hospital Episode Statistics data for England.

RESULTS

The total number of procedures has increased by 58 per cent. One-stage bone conduction hearing implantations in adults accounts for the largest proportion of this increase (93 per cent of the total). The number performed in children has remained stable and accounts for 73 per cent (n = 433) of all two-stage procedures.

CONCLUSION

The data show that bone conduction hearing implant surgery is becoming increasingly popular, particularly in adults. This has correlated with the increase in availability, national recommendations and choice of devices.

An Evaluation of Variations in the Carpal Tunnel Dimensions of Adult Subjects in a Hospital-Based Population: An Ultrasonographic Cross-Sectional Study

Background The carpal tunnel is a groove that spans the palm as a 'U.' The ulnar and radial sides of the wrist are made up of the scaphoid tubercle and trapezium while the palmar aspect is made up of carpal bones. Our study aimed to see whether there were differences in carpal tunnel size between men and women. Material and methods The study was conducted on 65 healthy adults, 13 (20%) were males and 52 (80%) were females (both non-pregnant and pregnant). Inclusion criteria were healthy adults and bilaterally symmetrical limbs. Exclusion criteria were chronic disease, diabetes, hypertension, immunological disorders, any visible abnormalities, and a history of upper extremity pain on either side. A high-resolution ultrasound machine with a linear transducer was used to perform an ultrasound scan of the carpal tunnel. The anteroposterior dimension was measured at the midline, or along the axis of the middle finger, and the transverse diameter was measured at the midpoint of the flexor retinaculum. The cross-sectional area of the tunnel was measured at its largest diameter within the carpal tunnel. All the dimensions were measured in centimeters. Results The mean transverse diameter of the right side was 1.824 ± 0.223 cm (p-value 0.002) and of the left side was 1.742 ± 0.197 cm (p-value 0.004). The mean cross-sectional area of the carpal tunnel on the right side was 1.417 ± 0.379 cm2 (p-value 0.008) and on the left side was 1.306 ± 0.303 cm2 (p-value 0.004), respectively. Age, sex, weight, and BMI were discussed. The carpal tunnels of females were found to be comparatively squarer and smaller than those of males. Conclusion The transverse diameter and cross-sectional area of the carpal tunnel and their correlation with carpal tunnel syndrome are predicted by age, sex, weight, and BMI. Both sexes had the same wrist ratio.

An Open-Source 3D-Printed Hindlimb Stabilization Apparatus for Reliable Measurement of Stimulation-Evoked Ankle Flexion in Rat

Currently there are numerous methods to evaluate peripheral nerve stimulation interfaces in rats, with stimulation-evoked ankle torque being one of the most prominent. Commercial rat ankle torque measurement systems and custom one-off solutions have been published in the literature. However, commercial systems are proprietary and costly and do not allow for customization. One-off lab-built systems have required specialized machining expertise, and building plans have previously not been made easily accessible. Here, detailed building plans are provided for a low-cost, open-source, and basic ankle torque measurement system from which additional customization can be made. A hindlimb stabilization apparatus was developed to secure and stabilize a rat's hindlimb, while allowing for simultaneous ankle-isometric torque and lower limb muscle electromyography (EMG). The design was composed mainly of adjustable 3D-printed components to accommodate anatomical differences between rat hindlimbs. Additionally, construction and calibration procedures of the rat hindlimb stabilization apparatus were demonstrated in this study. In vivo torque measurements were reliably acquired and corresponded to increasing stimulation amplitudes. Furthermore, implanted leads used for intramuscular EMG recordings complemented torque measurements and were used as an additional functional measurement in evaluating the performance of a peripheral nerve stimulation interface. In conclusion, an open-source and noninvasive platform, made primarily with 3D-printed components, was constructed for reliable data acquisition of evoked motor activity in rat models. The purpose of this apparatus is to provide researchers a versatile system with adjustable components that can be tailored to meet user-defined experimental requirements when evaluating motor function of the rat hindlimbs.

Recognizing the Less Explored "Active Solid"-"Moving Liquid" Interfaces in Bio/Chemical Sensors

Bio/chemical sensors possess a plethora of advantageous features that have proven to be invaluable tools in detecting and monitoring biomolecules, facilitating advancements in healthcare, environmental monitoring, food safety, and more. However, when it comes to their routine use in continuous fluid flow conditions, an intricate web of solid-liquid interfacial phenomena emerges, which requires a deep understanding of the sensor surface and fluid interations. These interfacial phenomena encompass a broad spectrum of physical, chemical, and biological processes, other than the actual detection, that influence the sensor's response. In this context, perhaps exploring a new theme "active solid"-"moving liquid" interface will unleash the full potential of bio/chemical sensors in any flow-based application.

Transcranial 3D ultrasound localization microscopy using a large element matrix array with a multi-lens diffracting layer: anin vitrostudy

Objective. Early diagnosis and acute knowledge of cerebral disease require to map the microflows of the whole brain. Recently, ultrasound localization microscopy (ULM) was applied to map and quantify blood microflows in 2D in the brain of adult patients down to the micron scale. Whole brain 3D clinical ULM remains challenging due to the transcranial energy loss which reduces significantly the imaging sensitivity.Approach. Large aperture probes with a large surface can increase both the field of view and sensitivity. However, a large active surface implies thousands of acoustic elements, which limits clinical translation. In a previous simulation study, we developed a new probe concept combining a limited number of elements and a large aperture. It is based on large elements, to increase sensitivity, and a multi-lens diffracting layer to improve the focusing quality. In this study, a 16 elements prototype, driven at 1 MHz frequency, was made andin vitroexperiments were performed to validate the imaging capabilities of this new probe concept.Main results. First, pressure fields emitted from a large single transducer element without and with diverging lens were compared. Low directivity was measured for the large element with the diverging lens while maintaining high transmit pressure. The focusing quality of 4 × 3cm matrix arrays of 16 elements without/with lenses were compared.In vitroexperiments in a water tank and through a human skull were achieved to localize and track microbubbles in tubes.Significance.ULM was achieved demonstrating the strong potential of multi-lens diffracting layer to enable microcirculation assessment over a large field of view through the bones.

Current Update on Biomarkers for Detection of Cancer: Comprehensive Analysis

Early and effective diagnosis of cancer is decisive for its proper management. In this context biomarker-based cancer diagnosis is budding as one of the promising ways for early detection, disease progression monitoring, and effective cancer therapy. Integration of Biosensing devices with different metallic/nonmetallic nanoparticles offers amplification and multiplexing capabilities for simultaneous detection of cancer biomarkers (CB's). This study provides a comprehensive analysis of the most recent designs and fabrication methodologies designed for developing electrochemical biosensors (EB) for early detection of cancers. The role of biomarkers in cancer therapeutics is also discussed.

Use of High-Frequency Transducers in Breast Sonography

Sonography companies have recently developed high-frequency transducers (20-30 MHz) to image the skin and small joints. In this pictorial review, we present a number of settings where these probes can be usefully employed to scan the breast. These include skin abnormalities of the breast and axilla; nipple-areolar complex abnormalities; superficial breast parenchyma abnormalities; breast parenchyma abnormalities in subjects with implants; very small female breasts; peripheral areas in breasts of any size; pre-puberal breasts; male breasts; post-mastectomy chest wall; and intraoperative breast sonography. Comparatively, side-by-side images obtained with conventional breast frequencies and high frequencies are shown.

Performance Evaluation of an Ultrasonic Imaging System Using Tissue-Mimicking Phantoms for Quality Assurance

Diagnostic ultrasound or sonography is an image that can provide valuable information for diagnosing and treating a variety of diseases and conditions. The aim of this research study is to examine the performance and accuracy of the ultrasonic imaging system for the guarantee of diagnosis quality assurance, and to adjust the penetration settings to minimize the time of repeat scans and maintenance duration during research experiments. Measurements in this experiment included the resolution (axial and lateral) and focal zones. Moreover, the evaluation was done by completing all the measurements at different depths on a multipurpose phantom model 539. The phantom was bought from the market and was not fabricated by the author. The measurements were achieved by applying two different transducers: curved and linear (flat). The ultrasound images were obtained and tested by using calipers (electronic), and the estimations and observations were read by using all the taken measurements and images. As a result, because the phantom depths were different, the penetration settings were different too, indicating that the depth impacted the penetrations of the created ultrasound image. Moreover, after the comparison of the recorded measurements and results, it was found that all measurements were within the accepted (standard) value and that the true value was specified by the production of the phantom.

Transducer Technologies for Biosensors and Their Wearable Applications

The development of new biosensor technologies and their active use as wearable devices have offered mobility and flexibility to conventional western medicine and personal fitness tracking. In the development of biosensors, transducers stand out as the main elements converting the signals sourced from a biological event into a detectable output. Combined with the suitable bio-receptors and the miniaturization of readout electronics, the functionality and design of the transducers play a key role in the construction of wearable devices for personal health control. Ever-growing research and industrial interest in new transducer technologies for point-of-care (POC) and wearable bio-detection have gained tremendous acceleration by the pandemic-induced digital health transformation. In this article, we provide a comprehensive review of transducers for biosensors and their wearable applications that empower users for the active tracking of biomarkers and personal health parameters.

Intraarterial papaverine for relief of catheter-induced peripheral arterial vasospasm during pediatric cardiac surgery: A randomized double-blind controlled trial

BACKGROUND

Maintaining the patency of peripheral arterial lines in pediatric patients during surgery can be challenging due to multiple factors, and catheter-related arterial vasospasm is a potentially modifiable cause. Papaverine, a potent vasodilator, improves arterial line patency when used as a continuous infusion in the pediatric intensive care setting, but this method is not convenient during surgery.

AIM

Extrapolating from the benefit seen in the intensive care unit, the authors hypothesize that a small-volume intraarterial bolus of papaverine immediately after arterial line placement will reduce vasospasm-related arterial line malfunction.

METHODS

This was a prospective, randomized, double-blind study. Patients less than 17 years of age undergoing cardiac surgery were enrolled. Patients were randomized into the heparin or papaverine groups. Immediately after arterial line insertion, an intraarterial bolus of heparin (2 units/ml, 1 ml) or papaverine (0.12 mg/ml, 1 ml) was administered (T1, Figure 1). An optimal waveform was defined as the ease of aspirating a standardized blood sample within 30 s, absence of cavitation when sampling, absence of color change at the catheter site during injection, and presence of a dicrotic notch. The primary outcome evaluated was the presence of an optimal arterial waveform at 5 min after the first randomized dose (T1 + 5 min). The secondary outcomes were the presence of optimal arterial waveform an hour after the first dose and the ability of papaverine to rescue suboptimal waveforms.

RESULTS

A total of 100 patients were enrolled in the study. Twelve patients were excluded from the analysis. Complete datasets after randomization were available in 88 patients (heparin group, n = 46; papaverine group, n = 42). At baseline, groups were similar for age, weight, arterial vessel size, and arterial line patency. At T1 + 5 min, an improvement in the waveform characteristics was observed in the papaverine group (heparin,39% [8/46] vs. papaverine, 64% [27/42]; p = .02; odds ratio, 2.8; 95% CI, 1.2 to 6.6, Figure 3, Table 2). At the end of 1 h, both groups showed continued improvement in arterial line patency. After the second dose, a higher number of patients in the heparin group had suboptimal waveforms and were treated with papaverine (heparin,37% [17/46] vs. papaverine,17% [7/42], p = .05). Patients in the heparin group treated with papaverine showed significant improvement in patency (13/17 vs. 3/7, p = .01). No serious adverse events were reported.

CONCLUSIONS

In pediatric patients, papaverine injection immediately after peripheral arterial catheter placement was associated with relief of vasospasm and improved initial arterial line patency. Further, papaverine can be used as a rescue to improve and maintain arterial line patency.

A Review on the Applications of Graphene in Mechanical Transduction

A pressing need to develop low-cost, environmentally friendly, and sensitive sensors has arisen with the advent of the always-connected paradigm of the internet-of-things (IoT). In particular, mechanical sensors have been widely studied in recent years for applications ranging from health monitoring, through mechanical biosignals, to structure integrity analysis. On the other hand, innovative ways to implement mechanical actuation have also been the focus of intense research in an attempt to close the circle of human-machine interaction, and move toward applications in flexible electronics. Due to its potential scalability, disposability, and outstanding properties, graphene has been thoroughly studied in the field of mechanical transduction. The applications of graphene in mechanical transduction are reviewed here. An overview of sensor and actuator applications is provided, covering different transduction mechanisms such as piezoresistivity, capacitive sensing, optically interrogated displacement, piezoelectricity, triboelectricity, electrostatic actuation, chemomechanical and thermomechanical actuation, as well as thermoacoustic emission. A critical review of the main approaches is presented within the scope of a wider discussion on the future of this so-called wonder material in the field of mechanical transduction.

Influence of the type of acoustic transducer in pure-tone audiometry

PURPOSE

To compare the air-conduction hearing thresholds obtained with different acoustic transducers and verify the users' preferences regarding them.

METHODS

This is a cross-sectional, analytical, observational study with 26 participants aged 18 to 30 years, with normal hearing and no history of exposure to high sound pressure levels or complaints of tinnitus at the time of the assessment. We surveyed their medical history and performed meatoscopy, pure-tone threshold audiometry, speech audiometry, and acoustic immittance. The auditory thresholds were surveyed twice, each time with a different type of acoustic transducer: insert (E-A-RTONE) and circumaural earphones (HDA200). The assessments were performed in a random order, with 5-minute intervals. In the end, we asked the participants which earphones they found more comfortable in the tests. The data were submitted to nonparametric statistical analysis.

RESULTS

Assessing the medians in the auditory threshold survey, the circumaural earphones obtained better results at 250, 500, 2000, and 6000 Hz, while the insert earphones were better at 3000 and 4000 Hz; there were no statistical differences at 1000 and 8000 Hz. The circumaural was elected the most comfortable earphone.

CONCLUSION

The circumaural earphones had better auditory thresholds at 250, 500, 2000, and 6000 Hz than the insert earphones and were reported by the patients as the most comfortable type of transducer.

Diagnostic and therapeutic value of ultrasonography in the detection of paralabral ganglion cysts with a curved array transducer: A case report

BACKGROUND

Paralabral cysts are a rare cause of shoulder pain. Linear ultrasound transducers are often used for musculoskeletal evaluation and intervention. However, the use of linear transducer is limited when the target structure is located deep and blocked by bony barriers, as is the case of paralabral ganglion cysts.

OBJECTIVE

This case report aims to describe a beneficial role of using a convex transducer on the evaluation and ultrasonography-guided intervention of paralabral cysts below the acromion.

CASE DESCRIPTION

Two patients visiting the outpatient clinic of Physical Medicine and Rehabilitation complained of severe pain during shoulder movement. Ultrasound scans with linear transducer detected rotator cuff lesions. Shoulder magnetic resonance imaging was done because of the persistent pain despite therapeutic interventions for the rotator cuff lesion, and confirmed paralabral cysts. Although a linear array transducer could not visualize the cystic lesion but could only perform suprascapular nerve block and intra-articular injection, the use of a convex array transducer improved the visualization of the cystic lesion which we treated using ultrasound-guided aspiration and intra-cystic injection. Visual analog scale and Shoulder Pain and Disability Index were checked to assess the treatment effect of each intervention. The intra-cystic injection with aspiration and intra-articular injection showed minimal to moderate improvement of pain score.

CONCLUSION

In pain related to shoulder movement, especially pain that continues despite appropriate treatment for rotator cuff lesions, ultrasound diagnosis of paralabral ganglion cysts using convex transducers will improve the diagnostic value and accuracy of intervention.

Switchable Transducers in GaN MEMS Resonators: Performance Comparison and Analysis

This work presents a comprehensive comparison of switchable electromechanical transducers in an AlN/GaN heterostructure toward the goal of reconfigurable RF building blocks in next-generation ad hoc radios. The transducers’ inherent switching was achieved by depleting a 2D electron gas (2DEG) channel, allowing an RF signal launched by interdigital transducers (IDTs) to effectively excite the symmetric (S_o) Lamb mode of vibration in the piezoelectric membrane. Different configurations for applying DC bias to the channel for electromechanical actuation in the piezoelectric are discussed. Complete suppression of the mechanical mode was achieved with the transducers in the OFF state. Equivalent circuit models were developed to extract parameters from measurements by fitting in both ON and OFF states. This is the first time that an extensive comparative study of the performance of different switchable transducers in their ON/OFF state is presented along with frequency scaling of the resonant mode. The switchable transducer with Ohmic IDTs and a Schottky control gate showed superior performance among the designs under consideration.

Two-Dimensional Material-Based Biosensors for Virus Detection

Viral infections are one of the major causes of mortality and economic losses worldwide. Consequently, efficient virus detection methods are crucial to determine the infection prevalence. However, most detection methods face challenges related to false-negative or false-positive results, long response times, high costs, and/or the need for specialized equipment and staff. Such issues can be overcome by access to low-cost and fast response point-of-care detection systems, and two-dimensional materials (2DMs) can play a critical role in this regard. Indeed, the unique and tunable physicochemical properties of 2DMs provide many advantages for developing biosensors for viral infections with high sensitivity and selectivity. Fast, accurate, and reliable detection, even at early infection stages by the virus, can be potentially enabled by highly accessible surface interactions between the 2DMs and the analytes. High selectivity can be obtained by functionalization of the 2DMs with antibodies, nucleic acids, proteins, peptides, or aptamers, allowing for specific binding to a particular virus, viral fingerprints, or proteins released by the host organism. Multiplexed detection and discrimination between different virus strains are also feasible. In this Review, we present a comprehensive overview of the major advances of 2DM-based biosensors for the detection of viruses. We describe the main factors governing the efficient interactions between viruses and 2DMs, making them ideal candidates for the detection of viral infections. We also critically detail their advantages and drawbacks, providing insights for the development of future biosensors for virus detection. Lastly, we provide suggestions to stimulate research in the fast expanding field of 2DMs that could help in designing advanced systems for preventing virus-related pandemics.

Identification and Analysis of Bacterial Contamination of Ultrasound Transducers and Multiuse Ultrasound Transmission Gel Bottle Tips Before and After the Aseptic Cleansing Technique

OBJECTIVES

To provide a descriptive analysis for species identification of culture and Gram stain results from ultrasound transducers and multiuse ultrasound transmission gel bottle tips in active clinical use and to compare bacterial cultures from ultrasound transducers before and after aseptic cleansing.

METHODS

A prospective blinded descriptive analytic study of 18 distinct clinical care sites within a single primary clinical institution was conducted. Before and after a disinfectant towel cleanse, transducers were pressed against tryptic soy agar contact plates. Plates were deidentified and submitted for blind incubation, Gram staining, and species identification with microsequencing. Results were classified as clinically relevant (CR) or non-clinically relevant. In total, 188 samples were analyzed: 80 from ultrasound transducers before and cleansing, 13 from multiuse gel bottle tips before and after cleansing, and 2 precleansing samples from the data collector's pen and badge.

RESULTS

Fifty-nine precleansing samples (73.8%) grew cultures with CR bacteria, and 21 samples (26.3%) did not. Staphylococcus simulans represented 31.0% of all positive culture samples. Thirteen postcleansing samples (16.3%) grew cultures with CR bacteria, equating to a 78.0% reduction of CR bacterial growth (likelihood ratio, 57.10; P < .001).

CONCLUSIONS

Ultrasound transducers have a notable CR bacterial burden and may serve as potential infective vectors. Aseptic cleansing effectively eliminates most of the bacterial load from ultrasound transducers, but some bacteria persist, presenting a risk of nosocomial infection with ultrasound-guided interventions. These findings support American Institute of Ultrasound in Medicine 2018 guidelines intended to ensure an appropriate level of transducer preparation based on the examination type while emphasizing rational infection control measures to minimize the risk of potential patient harm.

Carbon Nanomaterials as Versatile Platforms for Biosensing Applications

A biosensor is defined as a measuring system that includes a biological receptor unit with distinctive specificities toward target analytes. Such analytes include a wide range of biological origins such as DNAs of bacteria or viruses, or proteins generated from an immune system of infected or contaminated living organisms. They further include simple molecules such as glucose, ions, and vitamins. One of the major challenges in biosensor development is achieving efficient signal capture of biological recognition-transduction events. Carbon nanomaterials (CNs) are promising candidates to improve the sensitivity of biosensors while attaining low detection limits owing to their capability of immobilizing large quantities of bioreceptor units at a reduced volume, and they can also act as a transduction element. In addition, CNs can be adapted to functionalization and conjugation with organic compounds or metallic nanoparticles; the creation of surface functional groups offers new properties (e.g., physical, chemical, mechanical, electrical, and optical properties) to the nanomaterials. Because of these intriguing features, CNs have been extensively employed in biosensor applications. In particular, carbon nanotubes (CNTs), nanodiamonds, graphene, and fullerenes serve as scaffolds for the immobilization of biomolecules at their surface and are also used as transducers for the conversion of signals associated with the recognition of biological analytes. Herein, we provide a comprehensive review on the synthesis of CNs and their potential application to biosensors. In addition, we discuss the efforts to improve the mechanical and electrical properties of biosensors by combining different CNs.

Optical Bioelectronic Device Based on a Screen-Printed Electroluminescent Transducer

A new class of biosensing transducer based on alternating-current electroluminescent (ACEL) display is demonstrated. Unlike conventional ACEL displays where they have been rigidly used in flexible screens and advertising applications, here, the display is integrated with immunoassay and functioned as an optical transducer. Taking advantage of the reversed ACEL architecture, the display can be simply fabricated on an unconventional paper material without requiring the transparent indium tin oxide (ITO) electrode. The sensing mechanism relies on the promoted electronic conduction from the immunocomplex formation between immobilized antibody, antigen, and nanoparticle labeled antibody. As a result, the electroluminescence could be triggered off instantaneously. To demonstrate the device effectiveness, C-reactive protein (CRP), a particular biomarker of an inflammatory process and cardiovascular disease, is chosen as a model analyte in this work. Additionally, the applicability of the proposed platform is proved efficacious in human serums, showing negligible interference from nontargeting proteins. The sensing display is also capable of performing multiple assays (up to 8) within a single device. This bio-optoelectronic device represents a straightforward yet highly sensitive approach. This ACEL transducer is believed to explore new possibilities for biosensing and exploit in point-of-care testing.

Piezoelectricity and Biocompatibility of Flexible ScxAl(1-x)N Thin Films for Compliant MEMS Transducers

There is huge research activity in the development of flexible and biocompatible piezoelectric materials for next-generation compliant micro electro-mechanical systems (MEMS) transducers to be exploited in wearable devices and implants. This work reports for the first time on the development of flexible Sc_xAl_(1-x)N films deposited by sputtering technique onto polyimide substrates, assessing their piezoelectricity and biocompatibility. Flexible Sc_xAl_(1-x)N films have been analyzed in terms of morphological, structural, and piezoelectric properties. Sc_xAl_(1-x)N layer exhibits a good surface roughness of 4.40 nm and moderate piezoelectricity with an extracted effective piezoelectric coefficient (d₃₃^eff) value of 1.87 ± 0.06 pm/V, in good agreement with the diffraction pattern analysis results. Cell viability assay, performed to study the interaction of the Sc_xAl_(1-x)N films with human cell lines, shows that this material does not have significant effects on tested cells. Furthermore, the Sc_xAl_(1-x)N layer, integrated onto a flexible device and analyzed by bending/unbending measurements, shows a peak-to-peak open-circuit voltage (V_OC) of 0.32 V and a short-circuit current (I_SC) of 0.27 μA, with a generated power of 19.28 nW under optimal resistive load, thus demonstrating the potential of flexible Sc_xAl_(1-x)N films as active layers for next-generation wearable/implantable piezoelectrics.

Wireless Monitoring Using a Stretchable and Transparent Sensor Sheet Containing Metal Nanowires

Mechanically and visually imperceptible sensor sheets integrated with lightweight wireless loggers are employed in ultimate flexible hybrid electronics (FHE) to reduce vital stress/nervousness and monitor natural biosignal responses. The key technologies and applications for conceptual sensor system fabrication are reported, as exemplified by the use of a stretchable sensor sheet completely conforming to an individual's body surface to realize a low-noise wireless monitoring system (<1 µV) that can be attached to the human forehead for recording electroencephalograms. The above system can discriminate between Alzheimer's disease and the healthy state, thus offering a rapid in-home brain diagnosis possibility. Moreover, the introduction of metal nanowires to improve the transparency of the biocompatible sensor sheet allows one to wirelessly acquire electrocorticograms of nonhuman primates and simultaneously offers optogenetic stimulation such as toward-the-brain-machine interface under free movement. Also discussed are effective methods of improving electrical reliability, biocompatibility, miniaturization, etc., for metal nanowire based tracks and exploring the use of an organic amplifier as an important component to realize a flexible active probe with a high signal-to-noise ratio. Overall, ultimate FHE technologies are demonstrated to achieve efficient closed-loop systems for healthcare management, medical diagnostics, and preclinical studies in neuroscience and neuroengineering.

Advances in Ultrasound Mediated Transdermal Drug Delivery

Low frequency ultrasound-assisted drug delivery has been widely investigated as a non-invasive method to enhance the transdermal penetration of drugs. Using this technique, a brief application of ultrasound is used to permeabilize skin for a prolonged time. In this review, an overview on ultrasound is detailed to help explain the parameters that could be modulated to obtain the desired ultrasound parameters for enhanced transdermal drug delivery. The mechanisms of enhancement and the latest developments in the area of ultrasound-assisted transdermal drug delivery are discussed. Special emphasis is placed on the effects of ultrasound when used in combination with microneedles, electroporation and iontophoresis, and penetration enhancers. Further, this review summarizes the effect of ultrasound on skin integrity and the regulatory requirements for commercialization of the ultrasound based transdermal delivery instruments.

What are the Main Sensor Methods for Quantifying Pesticides in Agricultural Activities? A Review

In recent years, there has been an increase in pesticide use to improve crop production due to the growth of agricultural activities. Consequently, various pesticides have been present in the environment for an extended period of time. This review presents a general description of recent advances in the development of methods for the quantification of pesticides used in agricultural activities. Current advances focus on improving sensitivity and selectivity through the use of nanomaterials in both sensor assemblies and new biosensors. In this study, we summarize the electrochemical, optical, nano-colorimetric, piezoelectric, chemo-luminescent and fluorescent techniques related to the determination of agricultural pesticides. A brief description of each method and its applications, detection limit, purpose—which is to efficiently determine pesticides—cost and precision are considered. The main crops that are assessed in this study are bananas, although other fruits and vegetables contaminated with pesticides are also mentioned. While many studies have assessed biosensors for the determination of pesticides, the research in this area needs to be expanded to allow for a balance between agricultural activities and environmental protection.

Integrated Histotripsy and Bubble Coalescence Transducer for Rapid Tissue Ablation

Residual bubbles produced after collapse of a cavitation cloud provide cavitation nuclei for subsequent cavitation events, causing cavitation to occur repeatedly at the same discrete set of sites. This effect, referred to as cavitation memory, limits the efficiency of histotripsy soft tissue fractionation. Besides passively mitigating cavitation memory by using a low pulse repetition frequency (~1 Hz), an active strategy was developed by our group. In this strategy, low-amplitude ultrasound sequences were used to stimulate coalescence of residual bubbles. The goal of this work is to remove cavitation memory and achieve rapid, homogeneous lesion formation using a single phased array transducer. A 1-MHz integrated histotripsy and bubble coalescing (BC) transducer system with a specialized electronic driving system was built in house. High-amplitude ( MPa) histotripsy pulses and subsequent low-amplitude (~1-2 MPa) BC sequences were applied to a red blood cell tissue-mimicking phantom at a single focal site. Significant reduction of the cavitation memory effect and increase in the fractionation rate were observed by introducing BC sequence. Effects of BC pulsing parameters were further studied. The optimal BC parameters were then utilized to homogenize a mm² region at high rate.