Portable Systems Research Articles

Multi-Resolution Wavelet Fractal Analysis and Subtask Training for Enhancing Few-Shot Noisy Brainwave Recognition.

The integration of healthcare monitoring with Internet of Things (IoT) networks radically transforms the management and monitoring of human well-being. Portable and lightweight electroencephalography (EEG) systems with fewer electrodes have improved convenience and flexibility while retaining adequate accuracy. However, challenges emerge when dealing with real-time EEG data from IoT devices due to the presence of noisy samples, which impedes improvements in brainwave detection accuracy. Moreover, high inter-subject variability and substantial variability in EEG signals present difficulties for conventional data augmentation and subtask learning techniques, leading to poor generalizability. To address these issues, we present a novel framework for enhancing EEG-based recognition through multi-resolution data analysis, capturing features at different scales using wavelet fractals. The original data can be expanded many times after continuous wavelet transform (CWT) and recombination, alleviating insufficient training samples. In the transfer stage of deep learning (DL) models, we adopt a subtask learning approach to train the recognition model to generalize efficiently. This incorporates wavelets at various scales instead of exclusively considering average prediction performance across scales and paradigms. Through extensive experiments, we demonstrate that our proposed DL-based method excels at extracting features from small-scale and noisy EEG data. This significantly improves healthcare monitoring performance by mitigating the impact of noise introduced by the external environment.

Review of Carbon Nanotube Field Effect Transistor for Nanoscale Regime

Background: The need for high performance, small size, low delay, low power consumption, and long battery backup of portable systems is increasing with the advancement of technology. Many features of portable systems can be improved using scaling methods. In the scaling process, reducing the size of devices causes serious difficulties, including the short channel effect (SCE) and leakage current, which degenerates the characteristics of the systems. Objective: In this review paper, a trending carbon nanotube field effect transistor (CNTFET) technology is discussed in detail. CNTFET can replace the conventional metal oxide semiconductor field effect transistor (MOSFET) technology to overcome the SCE problems in the nanoscale regime and also meet the requirements of portable systems. Methods: The CNTFET is an extremely good nanoscale technology due to its one-dimension band structure, high transconductance, high electron mobility, superior control over channel formation, and better threshold voltage. This technology is used to construct high-performance and low-power circuits by replacing the MOSFET technology. CNTFET in comparison to MOSFET takes the carbon nanotube (CNT) as a channel region. Results: The value of threshold voltage in CNTFET changes with the diameter of CNT. The threshold voltage of the devices controls many parameters at the circuit-level design. Hence, the detailed operation and the characteristics of CNTFET devices are presented in this review paper. The existing CNTFET-based ternary full adder (TFA) circuits are also described in this review paper for the performance evaluation of different parameters. Conclusion: CNTFET technology is the possible solution for the SCE in the nanoscale regime and is capable to design efficient logic circuits. The circuits using the CNTFET technology can provide better performance and various advantages, including fast speed, small area, and low power consumption, in comparison to the MOSFET circuits. Thus, CNTFET technology is the best choice for circuit designs at the nanoscale.

Integrated Approach to the Optimization, Synthesis, Fabrication, and Application of ZnO-Based Sensors for Portable LPG Leakage Detection Systems

Liquefied petroleum gas (LPG) is used for cooking as well as in vehicles in the form of compressed natural gas (CNG) and in industries. As gas is volatile, there is the possibility of leakage which will be turned into take explosion or fire. It is a keen need to use the detection system for gas leakage for security purposes. ZnO thick film sensor was synthesized and fabricated by using the standard screen-printing method. The XRD pattern revealed that the ZnO thick film was polycrystalline, with an average crystallite size of around 27.1174 nm. The SEM scan revealed a ZnO particle size of around 1.88�m. Additionally, electrical and thermal properties were examined. This paper discussed the synthesized ZnO thick film LPG gas leakage detector prototype using Arduino ATMEGA8.

Barriers to integrating portable Magnetic Resonance Imaging systems in emergency medical service ambulances for stroke care

This study examines the barriers to integrating portable Magnetic Resonance Imaging (MRI) systems into ambulance services to enable effective triaging of patients to the appropriate hospitals for timely stroke care and potentially reduce door-to-needle time for thrombolytic administration. The study employs a qualitative methodology using a digital twin of the patient handling process developed and demonstrated through semi-structured interviews with 18 participants, including 11 paramedics from an Emergency Medical Services system and seven neurologists from a tertiary stroke care centre. The interview transcripts were thematically analysed to determine the barriers based on the Systems Engineering Initiative for Patient Safety framework. Key barriers include the need for MRI operation skills, procedural complexities in patient handling, space constraints, and the need for training and policy development. Potential solutions are suggested to mitigate these barriers. The findings can facilitate implementing MRI systems in ambulances to expedite stroke treatment.

Outcomes of endovascular therapy for Stanford type B aortic dissection in patients with sleep apnea syndrome

ObjectiveThis study aimed to determine the influences of varying severity of sleep apnea syndrome (SAS) on the outcomes after thoracic endovascular aorta repair (TEVAR) in patients with Stanford type B aortic dissection (TBAD). MethodsThis observational study focused on individuals with TBAD plus SAS who received TEVAR between January 2018 and December 2022. Patients were divided into groups according to the results of the portable sleep-breathing monitoring systems: mild SAS (MSAS) and moderate-to-severe SAS (MSSAS). Clinical profiles were collected and analyzed. ResultsA total of 121 cases with TBAD plus SAS who underwent TEVAR were enrolled in this study. Two groups were formed by stratifying these cases: MSAS (74 cases) and MSSAS (47 cases). The MSSAS cases were found to be older relative to MSAS cases (51.7 ± 8.3 years vs 57.1 ± 12.8 years; P = .012) and had a higher body mass index (BMI; 25.7 ± 2.3 kg/m2vs 27.0 ± 2.3 kg/m2; P = .038). The investigation did not find any appreciable differences between the MSAS and MSSAS groups in terms of complications (endoleak, P = .403; stent-induced new entry, P >.999; and stent displacement: P >.999). However, the MSSAS group exhibited a significantly higher overall mortality rate compared with the MSAS group (log-rank P = .027). The tendency continued when examining cases with Marfan syndrome combined with MSSAS, where the overall mortality rate was significantly greater compared with Marfan syndrome cases with MSAS (log-rank P = .037). The absence of a significant difference was noteworthy in the freedom from reintervention between the MSAS and MSSAS groups (log-rank P = .278). The overall mortality rate was significantly higher in MSSAS group even after adjusting for varying potential confounders in the multivariate cox regression analysis (hazard ratio [HR], 1.875; 95% confidence interval [CI], 1.238-2.586; P = .012). A markedly higher rate of distal stent dilation in the MSSAS group was also observed compared with the MSAS group (HR, 2.5 mm/year [95% CI, 2-3 mm/year] vs HR, 4 mm/year [95% CI, 2.0-5.5 mm/year]; P = .029). ConclusionsMSSAS is associated with a significantly higher risk of overall mortality and dilation rate of the distal stent after TEVAR for TBAD patients. Hence, aggressive efforts to reverse the severity of SAS in time in these individuals seem to be necessary.

Impact of diesel/renewable fuels blend on gaseous and particle emissions of a light-duty vehicle under real driving emissions

In this study, the environmental impact of Bio-butanol (BB) and Hydrotreated Vegetable Oil (HVO) use, each blended with diesel fuel, was investigated. To this aim, pollutant emissions were measured at the exhaust of an Euro 5 commercial light-duty vehicle, fueled with diesel, BB/diesel blend (10 %v BB) and HVO/diesel blend (15 %v HVO). The experimental activity was realized by performing Real Driving Emission (RDE) tests in Napoli (Italy), which allowed to measure total hydrocarbons (THC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOX), and particle emissions during the real use of vehicle by using a portable emission measurement systems (PEMS). The results show that the differences between fuels are small and not statistically significant for all emission parameters. CO and THC emissions increase with the renewable fuel blends, mainly with the BB blend in the urban environment due to the increasing of cold start contribution. NOX emissions increased with BB (by approximately 4 %) and decreased with the HVO (by approximately 13 %). With both renewable fuel blends, particle emissions at engine output were reduced by 25 %–41 % and fuel consumption by 6 %–10 % compared with diesel.

Experimental study on enhancing single-pass air disinfection efficacy for portable disinfection systems with different Far-UVC sources

Two single-pass air disinfection systems utilizing different form factors of Far-UVC sources were designed to achieve indoor air disinfection. The first system, namely the external-module-equipped (EME) system, featured a rectangular UV source module attached to the envelope of the disinfection box chamber. The second system, known as the internal-tube-equipped (ITE) system, incorporated a centrally positioned UV tube within the chamber. To assess their air disinfection efficacy, two bacteria, Salmonella enterica and Staphylococcus epidermidis, and one bacteriophage, MS2 were selected as challenges for the systems operating at a flow rate over 100 m3/h. The baseline EME system inactivated the microbes with the efficacies of 81.4 %, 16.9 %, and 25.1 % for S. enterica, S. epidermidis, and MS2, respectively. In comparison, the baseline ITE system demonstrated higher inactivation efficacies due to a wider irradiated area, with respective efficacies of 94.4 %, 25.8 %, and 37.8 % for the tested microorganisms. Two enhancement measures were implemented by redirecting airflow to the areas with high UV irradiance and enhancing UV reflectance, increasing the inactivation efficacy of the systems by up to 207.0 %. When tested against Staphylococcus epidermidis, compared with an upper-room Far-UVC, the modified EME and ITE systems presented an increase in inactivation rate by 23.0 % and 29.2 % respectively. These results demonstrated the potential of the systems to efficiently and sustainably inactivate a broad spectrum of microbes in future practical applications.

A Comparison of Hearing Thresholds, and the Resulting Prescribed Gain and Hearing Aid Outputs, Using Gold Standard Audiometry and the TympaHealth Hearing Assessment Tool.

Phone- and tablet-based hearing testing systems are now widely available. Here, we evaluated one such system from TympaHealth by comparing air conduction thresholds and resultant hearing aid targets and output, measured with the TympaHealth system with those measured using standard audiometry. The hearing thresholds of 35 adults were measured using standard audiometry and the TympaHealth system. Each set of thresholds was used to generate NAL-NL2 targets and program a hearing aid. The data from each system were compared. Bland-Altman analyses showed overall mean differences between thresholds measured with each system to be small, with 85% of TympaHealth thresholds being within ±5 dB of the standard audiometric thresholds, although TympaHealth thresholds were higher (poorer) than the standard audiometric thresholds. The hearing aid targets and gains generated from the standard audiometric thresholds were lower (less amplification) than those generated from the TympaHealth thresholds but again, mean differences at each frequency were small and likely imperceptible. These findings support the possibility that valid hearing testing can take place outside of a clinical booth using portable systems like that from TympaHealth, opening up the possibility of testing hearing and fitting hearing aids through pharmacies, opticians, and in care homes.

INDIDO: A novel low-power approach for domino logic circuits

Power dissipation in Nanoelectronic circuits at advanced technology nodes is dominated by leakage power dissipation. This is due to an increase in short channel effects in the scaled transistors.The VLSI industry is seeking alternative options to enhance the performance of portable electronic systems by ensuring higher speed and reduced power dissipation. In the ultra-deep submicron (DSM) regime, a new device called the fin-shaped field effect transistor (FinFET) was developed to replace CMOS technology. FinFET, a multi-gate device, significantly reduces power dissipation compared to planer MOS (Metal Oxide Semiconductor ) transistor, but it doesn’t entirely resolve the issue. To further reduce power dissipation in the ultra DSM regime, low power approaches are required. Domino logic, a widely-used dynamic logic, is commonly utilized in high-speed VLSI architectures. In this research work, a novel INput Dependent Inverter DOmino (INDIDO) logic approach for low-power domino logic circuits using FinFET devices is proposed. A comparative analysis between the proposed INDIDO method and the existing approaches is performed for domino logic circuits for various performance metrics at the 16 nm technology node. In this research, various circuits like domino buffer, domino OR, domino AND, domino XOR and domino half adder are designed using the proposed INDIDO approach.The proposed INDIDO FinFET buffer circuit offers significant improvement in energy efficiency and FOM (Figure of Merit) by 53.18% and 82% respectively as compared to conventional FinFET footed domino buffer circuit. Beside this, proposed circuits like INDIDO OR, INDIDO AND, INDIDO XOR and INDIDO Half adder circuit follow the same trend as INDIDO buffer circuit and show better performance parametres in comparison to the existing low power domino approaches as well. In addition to this, the proposed INDIDO buffer circuits are also analyzed for PVT(process voltage and temperature) variability.This whole analysis makes us to conclude that proposed INDIDO approach reduces power dissipation and delay penalty, have high noise tolerance capacity, more immunity against PVT variations and high energy efficiency in comparison to the already existing techniques.

Repeatability of image quality in very low-field MRI.

Very low-field MR has emerged as a promising complementary device to high-field MRI scanners, offering several advantages. One of the key benefits is that very low-field scanners are generally more portable and affordable to purchase and maintain, making them an attractive option for medical facilities looking to reduce costs. Very low-field MRI systems also have lower RF power deposition, making them safer and less likely to cause tissue heating or other safety concerns. They are also simpler to maintain, as they do not require cooling agents such as liquid helium. However, these portable MR scanners are impacted by temperature, lower magnetic field strength, and inhomogeneity, resulting in images with lower signal-to-noise ratio (SNR) and higher geometric distortions. It is essential to investigate and tabulate the variations in these parameters to establish bounds so that subsequent in vivo studies and deployment of these portable systems can be well informed. The aim of this work is to investigate the repeatability of image quality metrics such as SNR and geometrical distortion at 0.05 T over 10 days and three sessions per day. We acquired repeatability data over 10 days with three sessions per day. The measurements included temperature, humidity, transmit frequency, off-resonance maps, and 3D turbo spin echo (TSE) images of an in vitro phantom. This resulted in a protocol with 11 sequences. We also acquired a 3 T data set for reference. The image quality metrics included computing SNR and eccentricity (to assess geometrical distortion) to investigate the repeatability of 0.05 T image quality. The image reconstruction included drift correction, k-space filtering, and off-resonance correction. We computed the experimental parameters' coefficient of variation (CV) and the resulting image quality metrics to assess repeatability. We have explored the impact of electromagnetic interference (EMI) on image quality in very low-field MRI. The investigation involved varying both the distance and amplitude of the EMI-producing coil from the signal generator to analyze their effects on image quality. The range of temperature measured during the study was within 1.5 °C. The off-resonance maps acquired before and after the 3D TSE showed similar hotspots and were changed mainly by a global constant. The SNR measurements were highly repeatable across sessions and over the 10 days, quantified by a CV of 6.7%. The magnetic field inhomogeneity effects quantified by eccentricity showed a CV of 13.7%, but less than 5.1% in two of the three sessions over 10 days. The use of conjugate phase reconstruction mitigated geometrical distortion artifacts. Temperature and humidity did not significantly affect SNR or mean frequency drift within the ranges of these environmental factors investigated. The EMI experiment showed that as the amplitude increased the SNR decreased, and concurrently the root mean square of the background increased with a rise in EMI amplitude or a reduction in distance. We found that humidity and temperature in the range investigated did not impact SNR or frequency. Based on the CV values computed session-wise and for the overall study, our findings indicate high repeatability for SNR and magnetic field homogeneity.

Design and Analysis of a High-Gain, Low-Noise, and Low-Power Analog Front End for Electrocardiogram Acquisition in 45 nm Technology Using gm/ID Method

In this work, an analog front-end (AFE) circuit for an electrocardiogram (ECG) detection system has been designed, implemented, and investigated in an industry-standard Cadence simulation framework using an advanced technology node of 45 nm. The AFE consists of an instrumentation amplifier, a Butterworth band-pass filter (with fifth-order low-pass and second-order high-pass sections), and a second-order notch filter—all are based on two-stage, Miller-compensated operational transconductance amplifiers (OTA). The OTAs have been designed employing the gm/ID methodology. Both the pre-layout and post-layout simulation are carried out. The layout consumes an area of 0.00628 mm2 without the resistors and capacitors. Analysis of various simulation results are carried out for the proposed AFE. The circuit demonstrates a post-layout bandwidth of 239 Hz, with a variable gain between 44 and 58 dB, a notch depth of −56.4 dB at 50.1 Hz, a total harmonic distortion (THD) of −59.65 dB (less than 1%), an input-referred noise spectral density of <34 μVrms/Hz at the pass-band, a dynamic range of 52.71 dB, and a total power consumption of 10.88 μW with a supply of ±0.6 V. Hence, the AFE exhibits the promise of high-quality signal acquisition capability required for portable ECG detection systems in modern healthcare.

Criticality of Spray Solvent Choice on the Performance of Next Generation, Spray-Based Ambient Mass Spectrometric Ionization Sources: A Case Study Based on Synthetic Cannabinoid Forensic Evidence

Mass spectrometry (MS) is a highly selective and sensitive analytical tool with a myriad of applications, but such techniques are typically used in laboratory settings due to the handling and preparations that are necessary. The merging of two streams of robust research, portable MS systems and next-generation ambient ionization methods, now provides the ability to perform high-performance chemical screening in an on-site and on-demand manner, with natural applications in disciplines such as forensic science, where samples of interest are typically found in field environments (i.e., traffic stops, crime scenes, etc.). Correspondingly, investigations regarding the suitability and robustness of these methodologies when they are utilized for authentic forensic evidence processing are prudent. This work reports critical insights into the role that choice of spray solvent system plays regarding analytical performance of two spray-based ambient ionization sources, paper spray ionization (PSI) and filter cone spray ionization (FCSI), when employed for evidence types containing emerging synthetic cannabinoids. The systematic characterization studies reported herein show that the applied spray solvent can dramatically affect both spectral intensity and signal duration, and in some circumstances, yield deleterious false negative responses. Overall, acetonitrile-based systems are shown to strike a balance between analyte solubility concerns and spray ionization dynamics of the novel ion sources employed on portable MS systems.

An EEG channel selection method for motor imagery based on Fisher score and local optimization

Objective. Multi-channel electroencephalogram (EEG) technology in brain–computer interface (BCI) research offers the advantage of enhanced spatial resolution and system performance. However, this also implies that more time is needed in the data processing stage, which is not conducive to the rapid response of BCI. Hence, it is a necessary and challenging task to reduce the number of EEG channels while maintaining decoding effectiveness. Approach. In this paper, we propose a local optimization method based on the Fisher score for within-subject EEG channel selection. Initially, we extract the common spatial pattern characteristics of EEG signals in different bands, calculate Fisher scores for each channel based on these characteristics, and rank them accordingly. Subsequently, we employ a local optimization method to finalize the channel selection. Main results. On the BCI Competition IV Dataset IIa, our method selects an average of 11 channels across four bands, achieving an average accuracy of 79.37%. This represents a 6.52% improvement compared to using the full set of 22 channels. On our self-collected dataset, our method similarly achieves a significant improvement of 24.20% with less than half of the channels, resulting in an average accuracy of 76.95%. Significance. This research explores the importance of channel combinations in channel selection tasks and reveals that appropriately combining channels can further enhance the quality of channel selection. The results indicate that the model selected a small number of channels with higher accuracy in two-class motor imagery EEG classification tasks. Additionally, it improves the portability of BCI systems through channel selection and combinations, offering the potential for the development of portable BCI systems.

Characterization of a SiPM-based monolithic neutron scatter camera using dark counts

The Single Volume Scatter Camera (SVSC) Collaboration aims to develop portable neutron imaging systems for a variety of applications in nuclear non-proliferation. Conventional double-scatter neutron imagers are composed of several separate detector volumes organized in at least two planes. A neutron must scatter in two of these detector volumes for its initial trajectory to be reconstructed. As such, these systems typically have a large footprint and poor geometric efficiency. We report on the design and characterization of a prototype monolithic neutron scatter camera that is intended to significantly improve upon the geometrical shortcomings of conventional neutron cameras. The detector consists of a 50 mm×56 mm× 60 mm monolithic block of EJ-204 plastic scintillator instrumented on two faces with arrays of 64 Hamamatsu S13360-6075PE silicon photomultipliers (SiPMs). The electronic crosstalk is limited to < 5% between adjacent channels and < 0.1% between all other channel pairs. SiPMs introduce a significantly elevated dark count rate over PMTs, as well as correlated noise from after-pulsing and optical crosstalk. In this article, we characterize the dark count rate and optical crosstalk and present a modified event reconstruction likelihood function that accounts for them. We find that the average dark count rate per SiPM is 4.3 MHz with a standard deviation of 1.5 MHz among devices. The analysis method we employ to measure internal optical crosstalk also naturally yields the mean and width of the single-electron pulse height. We calculate separate contributions to the width of the single-electron pulse-height from electronic noise and avalanche fluctuations. We demonstrate a timing resolution for a single-photon pulse to be (128 ± 4) ps. Finally, coincidence analysis is employed to measure external (pixel-to-pixel) optical crosstalk. We present a map of the average external crosstalk probability between 2×4 groups of SiPMs, as well as the in-situ timing characteristics extracted from the coincidence analysis. Further work is needed to characterize the performance of the camera at reconstructing single- and double-site interactions, as well as image reconstruction.

Health monitoring system using ECG and PPG techniques

The demand for portable health monitoring systems has grown rapidly in recent years due to the increasing prevalence of chronic diseases and the need for continuous health monitoring. This article introduces the development and implementation of a portable health monitoring system using photo plethysmography (PPG) and electrocardiogram (ECG) technologies. The system integrates the Node MCU ESP8266 microcontroller, AD8232 ECG sensor, and MAX30100 sensor to measure vital signs such as heart rate and blood oxygen saturation level. The proposed system provides a cost-effective and efficient solution for real-time health monitoring, enabling early detection of abnormalities and timely intervention. The feasibility and performance of the system were proven through experimental tests.

Embedded Machine Learning System for Muscle Patterns Detection in a Patient with Shoulder Disarticulation.

The integration of artificial intelligence (AI) models in the classification of electromyographic (EMG) signals represents a significant advancement in the design of control systems for prostheses. This study explores the development of a portable system that classifies the electrical activity of three shoulder muscles in real time for actuator control, marking a milestone in the autonomy of prosthetic devices. Utilizing low-power microcontrollers, the system ensures continuous EMG signal recording, enhancing user mobility. Focusing on a case study-a 42-year-old man with left shoulder disarticulation-EMG activity was recorded over two days using a specifically designed electronic board. Data processing was performed using the Edge Impulse platform, renowned for its effectiveness in implementing AI on edge devices. The first day was dedicated to a training session with 150 repetitions spread across 30 trials and three different movements. Based on these data, the second day tested the AI model's ability to classify EMG signals in new movement executions in real time. The results demonstrate the potential of portable AI-based systems for prosthetic control, offering accurate and swift EMG signal classification that enhances prosthetic user functionality and experience. This study not only underscores the feasibility of real-time EMG signal classification but also paves the way for future research on practical applications and improvements in the quality of life for prosthetic users.

A novel imageless accelerometer-based navigation system improves acetabular cup placement accuracy during total hip arthroplasty in the lateral decubitus position.

The accuracy of acetabular cup placement using conventional portable imageless navigation systems in total hip arthroplasty (THA) in the lateral decubitus position remains challenging. Several novel portable imageless navigation systems have been developed recently to improve cup placement accuracy in THA. This study compared the accuracy of acetabular cup placement using a conventional accelerometer-based portable navigation (c-APN) system and a novel accelerometer-based portable navigation (n-APN) system during THA in the lateral decubitus position. This retrospective cohort study compared 45 THAs using the c-APN and 45 THAs using the n-APN system. The primary outcomes were the absolute errors between the intraoperative and postoperative values of acetabular cup radiographic inclination and anteversion angles and the percentage of cases with absolute errors within 5°. Intraoperative values were shown on navigation systems, and postoperative measurements were conducted using computed tomography images. The median absolute errors of the cup inclination angles were significantly smaller in the n-APN group than in the c-APN group (3.9° [interquartile range 2.2°-6.0°] versus 2.2° [interquartile range 1.0°-3.3°]; P = 0.002). Additionally, the median absolute errors of the cup anteversion angles were significantly smaller in the n-APN group than in the c-APN group (4.4° [interquartile range 2.4°-6.5°] versus 1.9° [interquartile range 0.8°-2.7°]; P < 0.001). Significant differences were observed in the percentage of cases with absolute errors within 5° of inclination (c-APN group 67% versus n-APN group 84%; P = 0.049) and anteversion angles (c-APN group 62% versus n-APN group 91%; P = 0.001). The n-APN system improved the accuracy of the cup placement compared to the c-APN system for THA in the lateral decubitus position.

Imaging performance of portable and conventional ultrasound imaging technologies for ophthalmic applications.

The aim of this study was to evaluate the imaging capabilities of Butterfly iQ with conventional ophthalmic (piezoelectric) ultrasound (COU) for ophthalmic imaging. Custom phantom molds were designed and imaged with Butterfly iQ and COU to compare spatial resolution capabilities. To evaluate the clinical imaging performance of Butterfly iQ and COU, a survey containing pathological conditions from human subjects, imaged with both Butterfly iQ and COU probes, was given to three retina specialists and graded on image detail, resolution, quality, and diagnostic confidence on a ten-point Likert scale. Kruskal-Wallis analysis was performed for survey responses. Butterfly iQ and COU had comparable capabilities for imaging small axial and lateral phantom features (down to 0.1 mm) of high and low acoustic reflectivity. One of three retina specialists demonstrated a statistically significant preference for COU related to resolution, detail, and diagnostic confidence, but the remaining graders showed no significant preference for Butterfly iQ or COU across all sample images presented. The emergence of portable ultrasound probes offers an affordable alternative to COU technologies with comparable qualitative imaging resolution down to 0.1 mm. These findings suggest the value to further study the use of portable ultrasound systems and their utility in routine eye care.

A Single-Output-Filter Double Dual Ćuk Converter

This study introduces an innovative version of a recently studied converter. A Double Dual Ćuk Converter was recently studied with advantages like the possibility of designing it for achieving a low-input current ripple. The proposed converter, called the Improved Double Dual Ćuk Converter, maintains the advantages of the former one, and it is characterized by requiring one less capacitor and inductor than its predecessor. This allows addressing the challenge of optimizing the topology to reduce component count without compromising the operation; this work proposes an efficient design methodology based on theoretical analysis and experimental validation. Results demonstrate that the improved topology not only retains the advantages of the previous version, including high efficiency and robustness, but also enhances power density by reducing the number of components. These advancements open new possibilities for applications requiring compact and efficient power converters, such as renewable energy systems, electric vehicles, and portable power supply systems. This work underscores the importance of continuous innovation in power converter design and lays the groundwork for future research aimed at optimizing converter topologies. A detailed discussion of the operating principles and modeling of the converter is provided. Furthermore, simulation outcomes highlighting differences in steady-state duration, output voltage, input current ripple, and operational efficiency are shared. The results from an experimental test bench are also presented to corroborate the efficacy of the improved converter.

Biosignature detection from amino acid enantiomers with portable GC systems

Biosignature detection from amino acid enantiomers with portable GC systems