Reagent storage and delivery on integrated microfluidic chips for point-of-care diagnostics.

Microfluidic-based point-of-care diagnostics offer several unique advantages over existing bioanalytical solutions, such as automation, miniaturisation, and integration of sensors to rapidly detect on-site specific biomarkers. It is important to highlight that a microfluidic POC system needs to perform a number of steps, including sample preparation, nucleic acid extraction, amplification, and detection. Each of these stages involves mixing and elution to go from sample to result. To address these complex sample preparation procedures, a vast number of different approaches have been developed to solve the problem of reagent storage and delivery. However, to date, no universal method has been proposed that can be applied as a working solution for all cases. Herein, both current self-contained (stored within the chip) and off-chip (stored in a separate device and brought together at the point of use) are reviewed, and their merits and limitations are discussed. This review focuses on reagent storage devices that could be integrated with microfluidic devices, discussing further issues or merits of these storage solutions in two different sections: direct on-chip storage and external storage with their application devices. Furthermore, the different microvalves and micropumps are considered to provide guidelines for designing appropriate integrated microfluidic point-of-care devices.

Developing the OpenFlexure Microscope towards medical use: technical and social challenges of developing globally accessible hardware for healthcare.

The OpenFlexure Microscope is an accessible, three-dimensional-printed robotic microscope, with sufficient image quality to resolve diagnostic features including parasites and cancerous cells. As access to lab-grade microscopes is a major challenge in global healthcare, the OpenFlexure Microscope has been developed to be manufactured, maintained and used in remote environments, supporting point-of-care diagnosis. The steps taken in transforming the hardware and software from an academic prototype towards an accepted medical device include addressing technical and social challenges, and are key for any innovation targeting improved effectiveness in low-resource healthcare. This article is part of the Theo Murphy meeting issue 'Open, reproducible hardware for microscopy'.

Flow cytometer for a dilution-free measurement approach with sample recollection.

Blood testing using flow cytometry is a common and rapid method for the initial screening and diagnosis of patients. Measurements are often combined with other scientific techniques, and analyzed samples are commonly diluted and discarded afterward. When the sample is recollected instead, sample dilution is a challenge when the sample is intended or needed for additional measurements. Therefore, it is advantageous to recollect the undiluted sample. In order to enable measurements of the same undiluted sample aliquot, we designed and constructed a purpose-built flow cytometer. Our instrument employs syringes, acoustic focusing, and an open fluidics system to recollect and reuse the unadulterated sample. The cytometer is compact, which reduces sample consumption. It acquires forward, sideward, and fluorescence signals, offering opportunities for diverse measurement approaches. In particular, our cytometer has been designed to be ready for additional downstream analysis of cells, e.g., applying mass spectrometry, magnetic resonance spectroscopy, or other analytical tools. This study presents results on instrument performance, a comparison with a cytometer that uses standard hydrodynamic focusing, and a proof of concept for multiple measurements.

Miniaturized preamplifier integration in ultrasound transducer design for enhanced photoacoustic imaging.

Photoacoustic imaging (PAI) utilizes the photoacoustic effect to record both vascular and functional characteristics of a biological tissue. Photoacoustic signals have typically low amplitude that cannot be read efficiently by data acquisition systems. This necessitates the use of one or more amplifiers. These amplifiers are somewhat bulky (e.g., the ZFL-500LN+, Mini-Circuits, USA, or 351A-3-50-NI, Analog Modules Inc., USA). Here, we describe the fabrication and development process of a transducer with a built-in low-noise preamplifier that is encased within the transducer housing. This new, to the best of our knowledge, design could be advantageous for applications where a compact transducer + preamplifier is required. We demonstrate the performance of this compact detection unit in a laser scanning photoacoustic microscopy system by imaging a rat ear ex vivo and a rat brain vasculature in vivo.

Use of Flow Restrictors in Congenital Heart Disease.

The surgical pulmonary artery band was first introduced in 1952 and, to this day, can produce challenges in regard to the ideal amount of restriction and the need for reoperations. A transcatheter option may be the ideal solution as it allows for a less-invasive approach for a better hemodynamic assessment and easier re-intervention. To date, multiple approaches have been developed with device modifications to create restrictions to flow, each with advantages and limitations. Continued experience is still necessary to determine the ideal device to use to create an adequate and modifiable level of restriction.

High-frequency harmonics suppression in high-speed railway through magnetic integrated LLCL filter.

The traction converter modulation generates switching-frequencies current harmonics. The trapped filters can eliminate these switching harmonics, reducing total inductance and filter size. Nonetheless, in comparison with the typical inductor-capacitor-inductor (LCL) filter, the trap inductor needs a larger magnetic core. Moreover, the trapped filter has not been analyzed in the traction systems. This paper proposes a magnetic integrated inductor-trap-inductor (LLCL) filter to decrease the filter's size and investigate its application in traction converters. In fact, the application range of this filter is quite broad, and it can be used in various electrical power systems, including industrial power systems, renewable energy systems, transportation systems, and building power systems. The LC-trap may be formed by connecting the equivalent trap inductor, introduced through the magnetic coupling between inverter-side and grid-side inductors, in series with the filter capacitor. Furthermore, for H-bridge unipolar pulse width modulation (PWM) traction converters, the prominent switching harmonics are concentrated at the double switching frequencies. Therefore, the stability zone is expanded by moving the resonance above the Nyquist frequency. The presented filter's features and design are thoroughly analyzed. The proposed method is finally validated by the MATLAB/Simulink simulation and hardware-in-the-loop (HIL) experimental results. Compared to the discrete windings, the integrated ones can save two magnetic cores. Furthermore, the proposed filter can meet IEEE criteria with 0.3% for all the harmonics and total harmonic distortion (THD) of 2.15% of the grid-side current.

Parapelvic Renal Cyst Treatment with Flexible Ureteroscopy: Single Centre Experience.

BACKGROUND: This study aimed to assess the feasibility, safety, and efficacy of an endoscopic parapelvic renal cyst (PRC) incision using flexible ureterorenoscopy (fURS). MATERIAL AND METHODS: We retrospectively reviewed data concerning 16 patients in whom PRC incisions had been performed using fURS between January 2016 and January 2022. Two patients were excluded from the study owing to a lack of follow-up information. The cysts of all the patients were evaluated preoperatively by computed tomography. The patients' age, gender, cyst size, presenting symptoms, postoperative complications, and pre- and post-treatment visual analogue scale (VAS) scores were evaluated. Surgical success was defined as a reduction of more than half of the cyst size in the sixth postoperative month. RESULTS: A total of 14 patients were included in this study. The patients' mean age was 52.6 ± 8.8 years, and the mean cyst size was 69.1 ± 15.5 mm. Twelve (85.7%) patients presented with flank pain. Clavien-Dindo grade 1 complications were observed in two patients (14.3%), and grade 2 complications were observed in one (7.1%). The median VAS scores were significantly lower after treatment than before in patients who presented with flank pain (2 (1-2.8) vs 8 (7-8), respectively; p = 0.002). Surgical success rate was detected in 11 patients (78.6%) six months after the treatment. CONCLUSIONS: Endoscopic incision of the PRC is a feasible treatment modality with high success rates and low complication rates. However, multicentre studies with larger populations and longer follow-ups are needed to evaluate the lasting effects.

Design and Stability Analysis of an Adaptive Neuro-Fuzzy Inference System (ANFIS)-Based Pacemaker Controller in MATLAB Simulink.

We present the design and stability analysis of an adaptive neuro-fuzzy inference system (ANFIS)-based controller of a pacemaker in MATLAB Simulink. ANFIS uses learning and speed properties of fuzzy and neural networks. Based on body states and preprogrammed situations of patients (age and sex, etc.), heart rate and amplitude of pacing pulse are changed. Output signal that is fed backed from heart is compared to the reference fuzzy bases ANFIS signals. After designing ANFIS based controller, the stability of the proposed system has been tested in both the time (step response) and trequency (Bode diagram and Nichols chart) domains. In our previous study, the step response analyzed and compared with other works. For frequency domain, all the possible frequency analysis methods have been tested but because of nonlinear properties of ANFIS, after linearization, just the Bode diagram achieved good results. The step response results in time domain is compared with previous work's results including optimum heart pulse rate for each particular patient. In the frequency domain, the Bode diagram stability analysis showed gain and phase margin as follows: GM (dB) = 42.1 and PM (deg) = 100.

[Design and application of a multiple combination portable auxiliary device for infusion].

Intravenous infusion is an important route of drug therapy, and infusion safety is an important issue for medical staff. Long-term and multiple infusion routes at the same time bring inconvenience to patients. Multiple three-way switches in parallel infusion may lead to interruption of the liquid route, which can seriously endanger the life of patients. To address these clinical issues, medical staff from the School of Basic Medical Sciences of Hebei Medical University and the Emergency Department of the Second Hospital of Hebei Medical University designed a multiple combination portable infusion assistance device and obtained the National Utility Model Patent of China (ZL 2022 2 0226073.2). The device is mainly composed of adhesive tape sticker, fixed slots and pipelines, and also includes a three-way valve and a mixing chamber, and different modes of infusion assist devices can be selected according to clinical needs. The device is simple and convenient to operate, solves the problem of multiple liquid infusion blockages, improves the safety and comfort of infusion, and can meet the needs of liquid infusion in various clinical situations.

A novel functional electrical stimulation sleeve based on textile-embedded dry electrodes.

BACKGROUND: Functional electrical stimulation (FES) is a rehabilitation technique that enables functional improvements in patients with motor control impairments. This study presents an original design and prototyping method for a smart sleeve for FES applications. The article explains how to integrate a carbon-based dry electrode into a textile structure and ensure an electrical connection between the electrodes and the stimulator for effective delivery of the FES. It also describes the materials and the step-by-step manufacturing processes. RESULTS: The carbon-based dry electrode is integrated into the textile substrate by a thermal compression molding process on an embroidered conductive matrix. This matrix is composed of textile silver-plated conductive yarns and is linked to the stimulator. Besides ensuring the electrical connection, the matrix improves the fixation between the textile substrate and the electrode. The stimulation intensity, the perceived comfort and the muscle torque generated by the smart FES sleeve were compared to hydrogel electrodes. The results show a better average comfort and a higher average stimulation intensity with the smart FES sleeve, while there were no significant differences for the muscle torque generated. CONCLUSIONS: The integration of the proposed dry electrodes into a textile is a viable solution. The wearable FES system does not negatively impact the electrodes' performance, and tends to improve it. Additionally, the proposed prototyping method is applicable to an entire garment in order to target all muscles. Moreover, the process is feasible for industrial production and commercialization since all materials and processes used are already available on the market.

In-situ Audiometry Compared to Conventional Audiometry for Hearing Aid Fitting.

The use of in-situ audiometry for hearing aid fitting is appealing due to its reduced resource and equipment requirements compared to standard approaches employing conventional audiometry alongside real-ear measures. However, its validity has been a subject of debate, as previous studies noted differences between hearing thresholds measured using conventional and in-situ audiometry. The differences were particularly notable for open-fit hearing aids, attributed to low-frequency leakage caused by the vent. Here, in-situ audiometry was investigated for six receiver-in-canal hearing aids from different manufacturers through three experiments. In Experiment I, the hearing aid gain was measured to investigate whether corrections were implemented to the prescribed target gain. In Experiment II, the in-situ stimuli were recorded to investigate if corrections were directly incorporated to the delivered in-situ stimulus. Finally, in Experiment III, hearing thresholds using in-situ and conventional audiometry were measured with real patients wearing open-fit hearing aids. Results indicated that (1) the hearing aid gain remained unaffected when measured with in-situ or conventional audiometry for all open-fit measurements, (2) the in-situ stimuli were adjusted for up to 30 dB at frequencies below 1000 Hz for all open-fit hearing aids except one, which also recommends the use of closed domes for all in-situ measurements, and (3) the mean interparticipant threshold difference fell within 5 dB for frequencies between 250 and 6000 Hz. The results clearly indicated that modern measured in-situ thresholds align (within 5 dB) with conventional thresholds measured, indicating the potential of in-situ audiometry for remote hearing care.

Risk Factors Associated with Misuse of Soft Mist Inhaler in Patients with Chronic Obstructive Pulmonary Disease.

Purpose: The use of inhaled bronchodilators is the mainstay of treatment for patients with chronic obstructive pulmonary disease (COPD). Although the soft mist inhaler (SMI) was developed to overcome the disadvantages of pressurized metered dose and drug powder inhalers, misuse during handling has been frequently observed in many studies. However, few studies have focused on SMI misuse among patients with COPD. Thus, we aimed to assess and identify the risk factors associated with SMI misuse among patients with COPD. Patient and Methods: In this prospective, observational, cross-sectional study, we enrolled patients with COPD who were undergoing SMI treatment between January 2018 and March 2020. An advanced nurse practitioner assessed the participants' handling of the device by using a check list. Results: Among 159 participants, 136 (85.5%) reported inhaler misuse. Duration of COPD and COPD assessment test (CAT) scores were positively associated with inhaler misuse; adherence and education level were negatively associated with inhaler misuse. In the multivariable analysis, a low educational level (less than high school), high CAT score (≥ 10), and short duration of COPD (≤ 2 years) were identified as risk factors for SMI misuse. Conclusion: SMI misuse remains common among patients with COPD. Therefore, clinicians should pay close attention to their patients using SMIs, especially in the early period after the diagnosis of COPD.

Skin-inspired, sensory robots for electronic implants.

Drawing inspiration from cohesive integration of skeletal muscles and sensory skins in vertebrate animals, we present a design strategy of soft robots, primarily consisting of an electronic skin (e-skin) and an artificial muscle. These robots integrate multifunctional sensing and on-demand actuation into a biocompatible platform using an in-situ solution-based method. They feature biomimetic designs that enable adaptive motions and stress-free contact with tissues, supported by a battery-free wireless module for untethered operation. Demonstrations range from a robotic cuff for detecting blood pressure, to a robotic gripper for tracking bladder volume, an ingestible robot for pH sensing and on-site drug delivery, and a robotic patch for quantifying cardiac function and delivering electrotherapy, highlighting the application versatilities and potentials of the bio-inspired soft robots. Our designs establish a universal strategy with a broad range of sensing and responsive materials, to form integrated soft robots for medical technology and beyond.

Compact and cost-effective laser-powered speckle contrast optical spectroscopy fiber-free device for measuring cerebral blood flow.

Significance: In the realm of cerebrovascular monitoring, primary metrics typically include blood pressure, which influences cerebral blood flow (CBF) and is contingent upon vessel radius. Measuring CBF noninvasively poses a persistent challenge, primarily attributed to the difficulty of accessing and obtaining signal from the brain. Aim: Our study aims to introduce a compact speckle contrast optical spectroscopy device for noninvasive CBF measurements at long source-to-detector distances, offering cost-effectiveness, and scalability while tracking blood flow (BF) with remarkable sensitivity and temporal resolution. Approach: The wearable sensor module consists solely of a laser diode and a board camera. It can be easily placed on a subject's head to measure BF at a sampling rate of 80 Hz. Results: Compared to the single-fiber-based version, the proposed device achieved a signal gain of about 70 times, showed superior stability, reproducibility, and signal-to-noise ratio for measuring BF at long source-to-detector distances. The device can be distributed in multiple configurations around the head. Conclusions: Given its cost-effectiveness, scalability, and simplicity, this laser-centric tool offers significant potential in advancing noninvasive cerebral monitoring technologies.

Designing a Smartphone-Based Pulse Oximeter for Children in South Africa (Phefumla Project): Qualitative Analysis of Human-Centered Design Workshops With Health Care Workers.

Background: Pulse oximeters noninvasively measure blood oxygen levels, but these devices have rarely been designed for low-resource settings and are inconsistently available at outpatient clinics. Objective: The Phefumla project aims to develop and validate a pediatric smartphone-based pulse oximeter designed specifically for this context. We present the process of human-centered oximeter design with health care workers in South Africa. Methods: We purposively sampled 19 health care workers from 5 clinics in Khayelitsha, Cape Town. Using a human-centered design approach, we conducted participatory workshops with four activities with health care workers: (1) they received 3D-printed prototypes of potential oximeter designs to provide feedback; (2) we demonstrated on dolls how they would use the novel oximeter; (3) they used pile sorting to rank design features and suggest additional features they desired; and (4) they designed their preferred user interface using a whiteboard, marker, and magnetized features that could be repositioned. We audio recorded the workshops, photographed outputs, and took detailed field notes. Analysis involved iterative review of these data to describe preferences, identify key design updates, and provide modifications. Results: Participants expressed a positive sentiment toward the idea of a smartphone pulse oximeter and suggested that a pediatric device would address an important gap in outpatient care. Specifically, participants expressed a preference for the prototype that they felt enabled more diversity in the way it could be used. There was a strong tendency to prioritize pragmatic design features, such as robustness, which was largely dictated by health care worker context. They also added features that would allow the oximeter device to serve other clinical functions in addition to oxygen saturation measurement, such as temperature and respiratory rate measurements. Conclusions: Our end user-centered rapid participatory approach led to tangible design changes and prompted design discussions that the team had not previously considered. Overall, health care workers prioritized pragmatism for pediatric pulse oximeter device design.

Metasurface-based dual-sense circularly polarized antenna for MIMO/full-duplex applications.

This paper introduces a two-element antenna array with dual-sense circular polarization, wideband operation, and high isolation characteristics. The antenna consists of two conventional truncated corner patches and an extra layer of metasurface (MS) located above the radiating patches. The overall dimensions of the proposed antenna are 0.92 λ0 × 0.73 λ0 × 0.05 λ0 and the element spacings are 0.02 λ0 and 0.39 λ0 with respect to edge-to-edge and center-to-center spacings. For validation, measurements on a fabricated antenna prototype are carried out. The measured data demonstrate that the presented MS-based antenna has a wide operating bandwidth of 14.5% with high isolation of better than 26 dB. The excellent performance could be concluded from the results of the investigation, which indicates that the proposed MS-based antenna could be a good candidate for multiple-input multiple-output (MIMO) and full-duplex applications.

Modeling the Intelligibility Benefit of Active Noise Cancelation in Hearing Devices That Improve Signal-to-Noise Ratio.

The extent to which active noise cancelation (ANC), when combined with hearing assistance, can improve speech intelligibility in noise is not well understood. One possible source of benefit is ANC's ability to reduce the sound level of the direct (i.e., vent-transmitted) path. This reduction lowers the "floor" imposed by the direct path, thereby allowing any increases to the signal-to-noise ratio (SNR) created in the amplified path to be "realized" at the eardrum. Here we used a modeling approach to estimate this benefit. We compared pairs of simulated hearing aids that differ only in terms of their ability to provide ANC and computed intelligibility metrics on their outputs. The difference in metric scores between simulated devices is termed the "ANC Benefit." These simulations show that ANC Benefit increases as (1) the environmental sound level increases, (2) the ability of the hearing aid to improve SNR increases, (3) the strength of the ANC increases, and (4) the hearing loss severity decreases. The predicted size of the ANC Benefit can be substantial. For a moderate hearing loss, the model predicts improvement in intelligibility metrics of >30% when environments are moderately loud (>70 dB SPL) and devices are moderately capable of increasing SNR (by >4 dB). It appears that ANC can be a critical ingredient in hearing devices that attempt to improve SNR in loud environments. ANC will become more and more important as advanced SNR-improving algorithms (e.g., artificial intelligence speech enhancement) are included in hearing devices.

Force/position tracking control of fracture reduction robot based on nonlinear disturbance observer and neural network.

BACKGROUND: For the fracture reduction robot, the position tracking accuracy and compliance are affected by dynamic loads from muscle stretching, uncertainties in robot dynamics models, and various internal and external disturbances. METHODS: A control method that integrates a Radial Basis Function Neural Network (RBFNN) with Nonlinear Disturbance Observer is proposed to enhance position tracking accuracy. Additionally, an admittance control is employed for force tracking to enhance the robot's compliance, thereby improving the safety. RESULTS: Experiments are conducted on a long bone fracture model with simulated muscle forces and the results demonstrate that the position tracking error is less than ±0.2 mm, the angular displacement error is less than ±0.3°, and the maximum force tracking error is 26.28 N. This result can meet surgery requirements. CONCLUSIONS: The control method shows promising outcomes in enhancing the safety and accuracy of long bone fracture reduction with robotic assistance.

Investigating visual preferences of clinical mechanical anesthetic vibration: a cross-sectional image survey.

While mechanical vibration lessens discomfort associated with injection site pain (ISP), many local anesthetic injectors (LAIs) do not use vibratory anesthetic devices (VADs). Injector preference of vibration device is influenced by functional concerns, but qualitatively there is an element of adoption that is driven by visual feedback. We sought to capture operator preferences of vibration device design elements to further understand why injectors do not use these devices. We conducted a survey of image preferences among nurses and medical assistants employed at 8 dermatological clinics to investigate barriers to VAD use. Images were electronically modified with features distinct from the original device (a VAD commonly used in clinical practice). Participants rated their likelihood and comfort of use of each VAD represented in the images. Two-sample t-tests were used to compare the rating of the unmodified VAD to each modified VAD within participants. A response rate of 100% was achieved with 35 participants (average age, 38.5 years; 6 (17.1%) male, 29 (82.9%) female). Despite 28 (80%) participants knowing that mechanical vibration reduces ISP, only 16 (45.7%) endorsed ever using mechanical vibration as topical anesthetic. Images modified by pattern, color, and sterility covering were rated significantly lower than the original, unmodified VAD image (plain white VAD), confirming that visual feedback does impact adoption. Through independent comment categorization, aesthetics were found to be important to LAIs. Aesthetic preferences opposing functional concerns may factor into the lack of VAD use. Defining these visual preference barriers to adoption may help promote VAD use during dermatologic procedures.

Australia II: A Case Study in Engineering Ethics.

Australia II became the first foreign yacht to win the America's Cup in 1983. The boat had a revolutionary wing keel and a better underwater hull form. In official documents, Ben Lexcen is credited with the design. He is also listed as the sole inventor of the wing keel in a patent application submitted on February 5, 1982. However, as reported in New York Times, Sydney Morning Herald, and Professional Boatbuilder, the wing keel was in fact designed by engineer Peter van Oossanen at the Netherlands Ship Model Basin in Wageningen, assisted by Dr. Joop Slooff at the National Aerospace Laboratory in Amsterdam. Based on telexes, letters, drawings, and other documents preserved in his personal archive, this paper presents van Oossanen's account of how the revolutionary wing keel was designed. This is followed by an ethical analysis by Martin Peterson, in which he applies the American NSPE and Dutch KIVI codes of ethics to the information provided by van Oossanen. The NSPE and KIVI codes give conflicting advice about the case, and it is not obvious which document is most relevant. This impasse is resolved by applying a method of applied ethics in which similarity-based reasoning is extended to cases that are not fully similar. The key idea, presented in Peterson's book The Ethics of Technology (Peterson, The ethics of technology: A geometric analysis of five moral principles, Oxford University Press, 2017), is to use moral paradigm cases as reference points for constructing a "moral map".