Custom Software Research Articles

Modular shadowgraph imaging for zooplankton ecological studies in diverse field and mesocosm settings

AbstractVarious iterations of shadowgraph imaging have been used to quantify zooplankton in situ with high spatial resolution. Because these systems can image relatively large volumes of water, they are especially useful for resolving less common meso‐ or macrozooplankton taxa (< 50 ind. m−3), such as larval fishes and gelatinous animals. However, larger volume imagers are typically integrated with heavy towed vehicles and deployed from research vessels, which introduces high costs and limits sampling approaches. Here we demonstrate that versatile configurations of shadowgraph imaging, including modular benchtop, handheld, and towed, compact vehicle systems (along with customizable software), allow for tailoring sampling to a variety of marine and freshwater settings (including mesocosms). These systems encompass a suite of possible architectures, designed for adapting the imaging depth of field, acquisition rates, sensor configuration, and deployment method to fit a wide range of sampling protocols, with high vertical resolution (~ 5 cm) and adequate taxonomic capabilities for > 0.5 mm organisms. The benchtop system facilitates an interactive approach to observe and quantify zooplankton behaviors and optical properties. Video footage from the benchtop system generates thousands of regions of interest min−1 for target organisms with variable orientations and swimming postures. When used in conjunction with in situ imaging, the benchtop system can build large machine learning training libraries targeted toward rare or morphologically diverse zooplankton, which often includes the larval stages of economically valuable taxa. These modular hardware and software components increase affordability and versatility while broadening the scope of scientific questions addressed by plankton imaging systems.

Mechanical wave velocities by clutter filter wave imaging detects myocardial dysfunction in acute coronary syndrome

Abstract Background/introduction Mechanical waves within the myocardium arising from physiologic events in the cardiac cycle such as the atrial kick (AK), mitral valve closure (MVC) and aortic valve closure (AVC) offer insight to tissue stiffness and can be measured by high frame rate echocardiography. Purpose To investigate the feasibility of measuring mechanical wave velocities in the left ventricle by clutter filter wave imaging (CFWI) and its potential for detecting regional myocardial dysfunction in patients with acute coronary syndrome. Methods We examined 60 patients (66±9 years of age, 72% male) with acute coronary syndrome by high frame rate echocardiography after revascularisation, imaging the left ventricle from the parasternal long axis view and three apical projections. Intrinsic mechanical waves generated by the AK, MVC and AVC were analysed off-line by CFWI of all walls using custom software (PyMWI) on 2000 frames of in-phase and quadrature component data per view extracted from a Vivid E95 scanner. Results We analysed a total number of 2372 waves recorded with a frame rate of 1180 (1134-1199) frames per second. The feasibility for measuring AK waves was high in all regions (mean 89%), but lower for the MVC and AVC waves with significant variability between regions (mean 44% and 46%, respectively; p<0.001). Feasibility declined from basal to apical segments for all waves (p=0.0001). Mean mechanical wave velocity was slowest for the AK wave at 2.5 (2.0-3.0) m/s, faster for the AVC wave at 5.1 (3.5-6.3) m/s and fastest for the MVC wave at 6.6 (4.9-8.6) m/s (p=0.0001). Basal AK wave velocity was faster in patients with basal wall motion abnormalities compared to those without (2.7 vs. 2.0 m/s, p=0.0004) and could detect the presence of wall motion abnormalities adjusting for age, gender and parameters of diastolic function (univariable OR 3.4, 95% CI 1.5-7.7, p<0.01; multivariable OR 4.4, 95% CI 1.4-14.1, p=0.01). Basal AK wave velocity detected wall motion abnormalities with an AUC of 0.78 with cut-off speeds of 2.3 m/s and 3.0 m/s, both correctly classifying 73% of cases (sensitivity/specificity 81%/68% and 43%/89%, respectively). Mechanical wave velocities of other waves and in other regions were not consistently and only weakly associated with echocardiographic parameters of systolic and diastolic function. Conclusion(s) Mechanical wave velocities by CFWI detects myocardial dysfunction in acute coronary syndrome. Elevated basal AK wave velocity was independently associated with myocardial dysfunction where AK wave velocity ≥2.3 m/s provided a good sensitivity and ≥3.0 m/s a good specificity for detecting regional wall motion abnormalities. The feasibility of measuring the AK wave was good, whereas MVC and AVC waves had lower feasibility and were inadequate for assessment of myocardial function. Feasibility variations between AK and MVC/AVC waves suggest differences in wave propagation dynamics or intrinsic wave properties.Illustration Clutter Filter Wave ImagingRisk of myocardial dysfunction

The left ventricular strain-volume loop in a healthy Dutch population: age- and sex related differences

Abstract Introduction By combining left ventricular (LV) global longitudinal strain (GLS) with LV volume during the cardiac cycle, LV strain-volume loops can be generated. LV SV-loop derived parameters provide new insights into the interaction between cardiac contraction and volume in a variety of cardiac diseases (1,2) and may even have prognostic value. (3,4) Reference values for healthy individuals with attention to sex- and age-related differences have not been established yet. Therefore, the aim of this study is to provide reference ranges in a healthy adult population and investigate potential sex- and age-related differences of LV SV-loop characteristics. Methods In 125 healthy volunteers aged 18-72 years, apical 2-, 3- and 4-chamber views were acquired to measure GLS. Custom software was used to combine strain and volume data to construct SV-loops. Different parameters were derived: (i)linear slope of systolic strain-volume relation (S-Slope); (ii) early linear slope of systolic strain-volume relation (ES-Slope); (iii) early linear slope of diastolic strain-volume relation (ED-Slope); and (iv) uncoupling between systolic and diastolic strain-volume relation (UNCOUP). Results For the systolic strain-volume relation higher values were observed in females as compared with males with S-Slope values of 0.19 [0.17-0.22] %/mL m-² and 0.13 [0.11-0.15] %/mL m-² respectively. ED-Slope was higher in females as compared with males with values of 0.18 [0.09-0.28] %/mL m-² and 0.12 [0.06-0.18] %/mL m-² respectively. Relative coupling of the systolic and diastolic strain-volume relation was observed with a mean value of 0.34 ± 1.1. UNCOUP was correlated with age with a value for r of 0.4. Conclusion Higher values for the systolic and early-diastolic strain-volume relation in females can be reflective of different cardiomechanics as LV contraction is not only comprised of longitudinal but also circumferential and radial deformation. In line with current literature our custom software found relative coupling of the systolic and diastolic strain-volume relation in our cohort of healthy subjects. Towards older age relative uncoupling of the systolic and diastolic strain-volume relation was found.Figure 1.Strain-volume loop

Interventricular abnormal septum displacement as contributory mechanism for impaired peak oxygen consumption and exercise cardiac output response in heart failure

Abstract Background In Heart failure (HF), the role of septum position and abnormal right ventricular (RV) geometry in determining exercise performance is unknown. Especially an abnormal interventricular septal (IVS) position is a well-known sign of RV pressure overload which affects left ventricular filling and output due to interdependence. Aim We postulated that an abnormal septum displacement during exercise and RV geometry alteration would affect peak exercise oxygen consumption (VO2) and cardiac output (CO) increase. Methods 17 HF patients with reduced ejection fraction (HFrEF) (mean age 71±12) underwent a cardiopulmonary exercise testing imaging (iCPET) with RV 3D-imaging analysis and were compared with a control population (mean age 67±14). 3D imaging of the RV chamber was examined off-line using the 4D RV TomTec software and obtained 3D mesh of the RV model using custom software to obtain the mean curvature value of IVS in 4 regions of: inflow tract (RVIT), outflow tract (RVOT), apical and body.We acquired measurements of curvature during end-diastole (ED) and at end systole (ES) phases and obtained a parametric curvature map. Results HF patients typically exhibited an abnormal of septal curve, with a more leftward configuration either at rest and under exercise (rest =−0.01±0.004 at ED, and −0.01±0.006 at ES; peak exercise= −0.01±0.004 at ED, and −0.01±0.004 at ES, Figure) compared to controls (rest=−0.02±0.003 at ED, and −0.02±0.005 at ES; peak exercise −0.02±0.008 at ED, and −0.03±0.006 at ES, Figure). Notably, the degree of the IVS curvature was found to linearly correlate with an impaired gas exchange performance as lower peak VO2 and a limited CO in HF (respectively r=0.62, p<0.001 and r=0.5, p<0.001 at ED during exercise; r=0.34, p<0.001 at ES during exercise, Figure). Conclusions In HF, the RV geometrical alterations reflected by an abnormal IVS displacement appear as novel contributory factors to a reduced exercise performance, impaired oxygen uptake and decreased CO.

Methods in fluctuation (noise) spectroscopy and continuous analysis for high-throughput measurements

Abstract Fluctuation (noise) spectroscopy is widely used to investigate the low-frequency dynamics of charge carriers in condensed-matter systems, aiming to (i) improve the performance of micro- and nanoscale electronic devices and sensors, and (ii) use ‘noise as a signal’ in order to fundamentally investigate the microscopic motion and transitions of charge carriers coupled to the low-lying excitations in solids. Here, we focus on measurements of the ubiquitous 1 / f -type fluctuations, often composed by a superposition of (independent or correlated) two-level systems each giving rise to a Lorentzian spectrum, denoted random telegraph noise in the time domain. We briefly review the basic concepts of noise and fluctuations and give a comprehensive overview of state-of-the-art measuring techniques, using both commercially available signal analyzers and custom software in order to perform the spectral analysis of the recorded time signals, and critically evaluate their advantages and drawbacks. We describe how to use fast data acquisition devices in a cross-correlation setup providing additional quantitative information on the magnitude of uncorrelated instrument noise, and demonstrate the mathematical intricacies of extracting the noise spectra. We introduce a new method for high-throughput measurements by automated spectral analysis based on the concept of Continuous Analysis. We demonstrate the potential of this technique, working towards a FAIR data workflow, by measurements of magnetic flux noise within the hysteresis loop of ferromagnetic nanostructures.

Feasibility of Low-Code Development Platforms in Precision Agriculture: Opportunities, Challenges, and Future Directions

Low-Code Development Platforms (LCDPs) empower users to create and deploy custom software with little to no programming. These platforms streamline development, offering benefits like faster time-to-market, reduced technical barriers, and broader participation in software creation, even for those without traditional coding skills. This study explores the application of LCDPs in Precision Agriculture (PA) through a systematic literature review (SLR). By analyzing the general characteristics and challenges of LCDPs, alongside insights from existing PA research, we assess their feasibility and potential impact in agricultural contexts. Our findings suggest that LCDPs can enable farmers and agricultural professionals to create tailored applications for real-time monitoring, data analysis, and automation, enhancing farming efficiency. However, challenges such as scalability, extensibility, data security, and integration with complex IoT systems must be addressed to fully realize the benefits of LCDPs in PA. This study contributes to the growing knowledge base in agricultural technology, offering valuable insights for researchers, practitioners, and policymakers looking to leverage LCDPs for sustainable and efficient farming practices.

Trimodal Watch-Type Wearable Health Monitoring Device

In the domain of healthcare, wearable health monitoring devices have emerged as essential tools for the advancement of patient health tracking. These devices facilitate the provision of real-time medical data to clinicians, enabling early diagnosis, timely intervention, and enhanced management of individual health. This study introduces an innovative trimodal wearable health monitoring device in the form of a wristwatch. The device integrates a breath analyzer for the assessment of gaseous phase biomarkers, a sweat analyzer for the evaluation of aqueous-phase biomarkers, and an infrared sensor for the measurement of body temperature in the optical phase. Engineered on a compact 3 cm × 3 cm printed circuit board, the device has been optimized for wearability, power efficiency, and seamless integration with both wired and wireless charging and communication systems. Furthermore, custom software applications, designed for both Windows and Android platforms, have been developed to facilitate intuitive data visualization and storage on personal computers and smartphones. Empirical results from real-time chemical testing substantiate the device’s efficacy and potential as an advanced solution for wearable health monitoring.

COVID-19 detection from exhaled breath

The SARS-CoV-2 coronavirus emerged in 2019 causing a COVID-19 pandemic that resulted in 7 million deaths out of 770 million reported cases over the next 4 years. The global health emergency called for unprecedented efforts to monitor and reduce the rate of infection, pushing the study of new diagnostic methods. In this paper, we introduce a cheap, fast, and non-invasive COVID-19 detection system, which exploits only exhaled breath. Specifically, provided an air sample, the mass spectra in the 10–351 mass-to-charge range are measured using an original micro and nano-sampling device coupled with a high-precision spectrometer; then, the raw spectra are processed by custom software algorithms; the clean and augmented data are eventually classified using state-of-the-art machine-learning algorithms. An uncontrolled clinical trial was conducted between 2021 and 2022 on 302 subjects who were concerned about being infected, either due to exhibiting symptoms or having recently recovered from illness. Despite the simplicity of use, our system showed a performance comparable to the traditional polymerase-chain-reaction and antigen testing in identifying cases of COVID-19 (that is, 95% accuracy, 94% recall, 96% specificity, and 92% \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$F_1$$\\end{document}-score). In light of these outcomes, we think that the proposed system holds the potential for substantial contributions to routine screenings and expedited responses during future epidemics, as it yields results comparable to state-of-the-art methods, providing them in a more rapid and less invasive manner.

Evaluation of the performance of a machine learning based atrial fibrillation screening algorithm using an oscillometric blood pressure monitor

Blood pressure monitors (BPMs) with atrial fibrillation (AFib) detection function can be used to detect AFib early. However, conventional algorithms require multiple BP measurements. Here, the feasibility of a machine-learning-based approach for AFib detection through single BP measurement was evaluated. First, a custom AdaBoost-based software, which analyzes the pulse-to-pulse interval (PPI) pattern and classifies it based on AFib detection, was created. Then, its classification performance was validated. For the validation study, PPI and standard 12-lead electrocardiogram (ECG) datasets were collected from 79 and 92 Japanese participants with and without AFib, respectively. PPI data were obtained using two different BPMs. All ECG results were interpreted by cardiologists. The custom software output for the PPI dataset and ECG interpreted results was compared, and the sensitivity and specificity were calculated. A sensitivity and specificity for PPI from main device were 97.5% (95% confidence interval [CI] 91.2–99.3%) and 98.9 (95% CI 94.1–99.8), respectively. No significant differences in sensitivity and specificity were observed in the subgroup analysis between different devices, age groups, and arm size groups. These results reflect the high accuracy and robustness of this AFib algorithm using a single BP measurement and supports its use for widespread AFib screening.

Support Personas: A Concept for Tailored Support of Users of Privacy-Enhancing Technologies

In many applications and websites people use in their everyday life, their privacy and data are threatened, e.g., by script tracking during browsing. Although researchers and companies have developed privacy-enhancing technologies (PETs), they are often difficult to use for lay users. In this paper, we conducted a literature review to classify users into different extit{support personas} based on their privacy competence and privacy concern. With developers of PETs in mind, support personas were envisioned to facilitate the customization of software according to the support needs of different users. In order to demonstrate the usefulness of support personas and based on workshop sessions with 15 participants, we designed a browser extension that supports users with the issue of script tracking by providing different user interfaces for different support personas. The following qualitative evaluation with 31 participants showed that the developed UI elements worked as intended for the different support personas. Therefore, we conclude the concept of support personas is useful in the development process of usable applications that enhance the privacy of the users while also educating them and thus potentially increasing their privacy literacy.

REFORMULANDO O JOGO TRIBUTÁRIO: DESAFIOS E SOLUÇÕES NAS TRANSAÇÕES DE GAMES ON-LINE

In recent years, computer games have gained widespread popularity, driven by technological advancements and internet expansion, leading to the prevalence of on-line gaming and the decline of physical media. The taxation of these games has become a debated issue, particularly regarding the differentiation between off-the-shelf and custom software. In 2021, the Brazilian Supreme Federal Court deemed software taxable as services. Uncertainties have arisen regarding in-game transactions, encompassing the acquisition of goods, rights, or financial operations. This article aims to understand whether transactions in on-line games qualify as the acquisition of goods or services, determining the applicable taxes, considering the Brazilian legal landscape post-Tax Reform. Specific objectives include grasping technical distinctions between goods, commodities, and services; conceptualizing and distinguishing software and on-line games from a technological perspective; outlining types of transactions in on-line games to support their legal classification; understanding the Supreme Court's rationale on software as services; and analyzing the impact of the Tax Reform on the taxation of in-game transactions. The research, characterized as pure and explanatory, employs a qualitative approach, deductive method, and bibliographic/documentary procedures. It concludes that the accurate taxation of on-line gaming transactions is a significant source of legal uncertainty, stemming from the classification and legality of tax incidence. The Tax Reform, by instituting a single tax for operations involving goods, services, and rights, holds the potential to resolve these uncertainties, rendering unnecessary the determination of the nature of operations for tax purposes.

Augmented reality for point-of-care ultrasound-guided vascular access in pediatric patients using Microsoft HoloLens 2: a preliminary evaluation.

Conventional ultrasound-guided vascular access procedures are challenging due to the need for anatomical understanding, precise needle manipulation, and hand-eye coordination. Recently, augmented reality (AR)-based guidance has emerged as an aid to improve procedural efficiency and potential outcomes. However, its application in pediatric vascular access has not been comprehensively evaluated. We developed an AR ultrasound application, HoloUS, using the Microsoft HoloLens 2 to display live ultrasound images directly in the proceduralist's field of view. We presented our evaluation of the effect of using the Microsoft HoloLens 2 for point-of-care ultrasound (POCUS)-guided vascular access in 30 pediatric patients. A custom software module was developed on a tablet capable of capturing the moving ultrasound image from any ultrasound machine's screen. The captured image was compressed and sent to the HoloLens 2 via a hotspot without needing Internet access. On the HoloLens 2, we developed a custom software module to receive, decompress, and display the live ultrasound image. Hand gesture and voice command features were implemented for the user to reposition, resize, and change the gain and the contrast of the image. We evaluated 30 (15 successful control and 12 successful interventional) cases completed in a single-center, prospective, randomized study. The mean overall rendering latency and the rendering frame rate of the HoloUS application were 139.30ms and 30 frames per second, respectively. The average procedure completion time was 17.3% shorter using AR guidance. The numbers of puncture attempts and needle redirections were similar between the two groups, and the number of head adjustments was minimal in the interventional group. We presented our evaluation of the results from the first study using the Microsoft HoloLens 2 that investigates AR-based POCUS-guided vascular access in pediatric patients. Our evaluation confirmed clinical feasibility and potential improvement in procedural efficiency.

Large scale massively parallel numerical simulation for blast effects on structures

An efficient large-scale parallel computing program for blast effects on structures is developed based on software platform mode, which adopts component-based three-layer software architecture to achieve disciplinary hierarchy. The parallel layer encapsulates high-performance data structures and shields large-scale parallel computing technology, enabling efficient mesh adaptivity. The common numerical algorithm layer encapsulates fluid, structural, and coupling algorithm processes providing standardized interfaces for extending numerical schemes. The physical model layer provides extension interfaces for state equations, source terms, initial boundary values, etc, to facilitate quick customization of large-scale parallel software for blast effects on structures. Typical examples verify the correctness, effectiveness and high precision of the proposed program in fluid-structure coupling problems. The parallel efficiency of 300,000 processor cores with hundreds of millions of grids reach 60.84% for the shock wave transmission. Finally, the dynamic behavior of multi-storey buildings under blast waves is simulated to reveal the damage model of the overall collapse. These results show that the software has a broad application prospect in the field of explosion. The results suggest that the software holds significant potential for application in the field of explosion, particularly in intricate and large-scale scenarios.

Development and Application of Unmanned Aerial High-Resolution Convex Grating Dispersion Hyperspectral Imager.

This study presents the design and development of a high-resolution convex grating dispersion hyperspectral imaging system tailored for unmanned aerial vehicle (UAV) remote sensing applications. The system operates within a spectral range of 400 to 1000 nm, encompassing over 150 channels, and achieves an average spectral resolution of less than 4 nm. It features a field of view of 30°, a focal length of 20 mm, a compact volume of only 200 mm × 167 mm × 78 mm, and a total weight of less than 1.5 kg. Based on the design specifications, the system was meticulously adjusted, calibrated, and tested. Additionally, custom software for the hyperspectral system was independently developed to facilitate functions such as control parameter adjustments, real-time display, and data preprocessing of the hyperspectral camera. Subsequently, the prototype was integrated onto a drone for remote sensing observations of Spartina alterniflora at Yangkou Beach in Shouguang City, Shandong Province. Various algorithms were employed for data classification and comparison, with support vector machine (SVM) and neural network algorithms demonstrating superior classification accuracy. The experimental results indicate that the UAV-based hyperspectral imaging system exhibits high imaging quality, minimal distortion, excellent resolution, an expansive camera field of view, a broad detection range, high experimental efficiency, and remarkable capabilities for remote sensing detection.

Comparison of long-term changes in the effective optical zone following SMILE and FS-LASIK for moderate and high myopia

BackgroundVisual quality after corneal refractive surgery is linked to the postoperative effective optical zone (EOZ). This study aims to compare long-term changes in the EOZ following small incision lenticule extraction (SMILE) and femtosecond laser-assisted in-situ keratomileusis (FS-LASIK) for moderate and high myopia.MethodsThis study included 42 patients (72 eyes) who underwent either SMILE (36 eyes) or FS-LASIK (36 eyes). A custom software program based on the tangential curvature difference map of the Pentacam HR (Oculus Optikgeräte GmbH) was used to define the EOZ at 3 and 7 years postoperatively. The EOZ, its chronological changes compared to the programmed optical zone (POZ), and the corneal wavefront aberrations following SMILE and FS-LASIK were analyzed. Correlations between the EOZ changes and relevant parameters were evaluated.ResultsThree years postoperatively, EOZ following SMILE and FS-LASIK were 5.13 ± 0.27 mm and 4.70 ± 0.24 mm (P < 0.001), respectively. Seven years postoperatively, EOZ following SMILE and FS-LASIK decreased to 5.03 ± 0.28 mm and 4.63 ± 0.23 mm (P < 0.001), respectively. At postoperative 7 years, the percentages of EOZ/POZ were negatively correlated with Q-value changes (β = -5.120, P = 0.009) following SMILE and positively correlated with the cylinder correction (β = 1.184, P = 0.004) following FS-LASIK. The induced spherical aberrations in the SMILE group were less than those in the FS-LASIK group (P < 0.05) and were negatively correlated with the EOZ/POZ (β = -16.653, P < 0.001).ConclusionsThe EOZ following SMILE was larger than that following FS-LASIK in the long postoperative term for moderate and high myopia. Furthermore, a continual reduction in the EOZ was noted after both surgical modalities.

Patterns of osteoarthritis in long finger joints: an observational cadaveric study with potential biomechanical considerations

PurposeTo explore the distribution and prevalence of osteoarthritis in metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints in long fingers in a cadaveric study, and to discuss potential biomechanical influences on these patterns. MethodsThis cadaveric study evaluated 144 metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints from 12 embalmed cadaver hands. A dorsal dissection approach was used to expose the joints, which were then marked with color-coded pegs for consistent orientation during imaging. High-resolution digital images of the distal articular surfaces were captured for analysis. The images were analyzed using custom software to quantify osteoarthritic areas, distinguishing between radial and ulnar aspects. Percentage affected joint surface was calculated using pixel-based measurements. Statistical analysis was used the Student t-test and ANOVA, with the significance threshold set at p < 0.05 and 95% confidence intervals ResultsThe ulnar side of the proximal interphalangeal joint in digits 2 and 3 showed higher prevalence of osteoarthritis (59.31% ± 15.48%) than the radial side (40.68% ± 15.48%), p = 0.007; in contrast, for digits 4 and 5, prevalence was greater on the radial (54.3% ± 10.99%) than the ulnar side (45.7% ± 10.99%), p = 0.007. No significant differences were noted in osteoarthritis distribution between the radial and ulnar aspects of the metacarpophalangeal and distal interphalangeal joints. ConclusionsThis study identified distinct patterns of osteoarthritis distribution in long-finger joints, with greater prevalence in the proximal interphalangeal joints. Although there were differences between stable (digits 2 and 3) and mobile (digits 4 and 5) fingers, further research is necessary to conclusively determine the role of biomechanical forces in the development of osteoarthritis. These findings lay the groundwork for future studies of the pathophysiology of osteoarthritis in the hand, and could guide the development of preventive and therapeutic interventions.

Menthyl acetate powered self-propelled Janus sponge Marangoni motors with self-maintaining surface tension gradients and active mixing

HypothesisSmall scale Marangoni motors, which self-generate motion by inducing surface tension gradients on water interfaces through release of surface-active “fuels”, have recently been proposed as self-powered mixing devices for low volume fluids. Such devices however, often show self-limiting lifespans due to the rapid saturation of surface-active agents. A potential solution to this is the use volatile surface-active agents which do not persist in their environment. Here we investigate menthyl acetate (MA) as a safe, inexpensive and non-persistent fuel for Marangoni motors. ExperimentsMA was loaded asymmetrically into millimeter scale silicone sponges. Menthyl acetate reacts slowly with water to produce the volatile surface-active menthol, which induces surface tension gradients across the sponge to drive motion by the Marangoni effect. Videos were taken and trajectories determined by custom software. Mixing was assessed by the ability of Marangoni motors to homogenize milliliter scale aqueous solutions containing colloidal sediments. FindingsMarangoni motors, loaded with asymmetric “Janus” distributions of menthyl acetate show velocities and rotational speeds up to 30 mm s−1 and 500 RPM respectively, with their functional lifetimes scaling linearly with fuel volume. We show these devices are capable of enhanced mixing of solutions at orders of magnitude greater rates than diffusion alone.

CyberUnits Bricks: An Implementation Study of a Class Library for Simulating Nonlinear Biological Feedback Loops

Feedback loops and other types of information processing structures play a pivotal role in maintaining the internal milieu of living organisms. Although methods of biomedical cybernetics and systems biology help to translate between the structure and function of processing structures, computer simulations are necessary for studying nonlinear systems and the full range of dynamic responses of feedback control systems. Currently, available approaches for modelling and simulation comprise basically domain-specific environments, toolkits for computer algebra systems and custom software written in universal programming languages for a specific purpose, respectively. All of these approaches are faced with certain weaknesses. We therefore developed a cross-platform class library that provides versatile building bricks for writing computer simulations in a universal programming language (CyberUnits Bricks). It supports the definition of models, the simulative analysis of linear and nonlinear systems in the time and frequency domain and the plotting of block diagrams. We compared several programming languages that are commonly used in biomedical research (S in the R implementation and Python) or that are optimized for speed (Swift, C++ and Object Pascal). In benchmarking experiments with two prototypical feedback loops, we found the implementations in Object Pascal to deliver the fastest results. CyberUnits Bricks is available as open-source software that has been optimised for Embarcadero Delphi and the Lazarus IDE for Free Pascal.

Examining the relative contribution of slow-burning inflammation and chronic demyelination to axonal damage in chronic multiple sclerosis lesions

Background and ObjectivesSlow-burning inflammation at the edge, and chronic demyelination at the core, of established multiple sclerosis (MS) lesions are potential mediators of disease progression. However, their relative contribution to progressive axonal damage has not been explored. Therefore, in this study, we investigated the comparative contribution of slow-burning inflammation and chronic demyelination to axonal attrition within MS lesions by measuring progressive tissue rarefaction. In addition, we use the visual system as a model to investigate the effect of chronic demyelination on the acceleration of axonal death in a sub-group of patients with unilateral optic neuritis. MethodsPre- and post-gadolinium 3D-T1, 3D FLAIR, diffusion tensor images, Optical Coherence tomography and multifocal visual evoked potentials were acquired from 52 relapsing-remitting MS patients who completed at least 5 years follow-up.Lesion expansion was measured using custom software, and the rate of tissue rarefication inside lesion core was assessed by measuring increase of normalized mean diffusivity (nMD). Axonal loss was also examined in eyes with severe optic nerve demyelination. ResultsAmong the 361 lesions analyzed, 104 were expanding (a minimum of 4 % expansion per year) and 257 were stable. Expanding lesions showed a significantly higher rate of progressive tissue rarefication inside lesion (1.12 % per year) core compared to stable lesions (0.21 % per year, p = 0.01). The magnitude of nMD change was significantly correlated with the rate of lesion expansion (r = 0.4, p < 0.001). Analysis of retinal ganglion cells in eyes with severe optic nerve demyelination (Inter-eye latency delay of >10 ms) revealed a similar rate of axonal loss (0.19 %) to the degree of tissue rarefaction observed in stable lesions (0.21 %). DiscussionThe results of the study suggest that the slow-burning inflammation at the lesion's edge (as measured by lesion expansion), is likely to have a greater impact on tissue damage (as measured by nMD change), when compared to stable chronically demyelinated lesions. The similar modest degree of tissue damage was also observed in chronically demyelinated fibers of the optic nerve.

Design and Development of a Powered Myoelectric Elbow Orthosis for Neuromuscular Injuries.

Recovering from neuromuscular injuries or conditions can be a challenging journey that involves complex surgeries and extensive physical rehabilitation. During this process, individuals often rely on orthotic devices to support and enable movement of the affected limb. However, users have criticized current commercially available powered orthotic devices for their bulky and heavy design. To address these limitations, we developed a novel powered myoelectric elbow orthosis. The orthosis incorporates 3 mechanisms: a solenoid brake, a Bowden cable-powered constant torque elbow mechanism, and an extension limiter. The device controller and battery are in a backpack to reduce the weight on the affected arm. We performed extensive calculations and testing to ensure that the orthosis could withstand at least 15 Nm of elbow torque. We developed a custom software effectively control the orthosis, enhancing its usability and functionality. A certified orthotist fitted a subject who had undergone a gracilis free functioning muscle transfer surgery with the device. We studied the subject under Mayo clinic IRB no. 20-006849 and obtained objective measurements to assess the orthosis's impact on upper extremity functionality during daily activities. The results are promising since the orthosis significantly improved elbow flexion range of motion by 40° and reduced compensatory movements at the shoulder (humerothoracic joint) by 50°. Additionally, the subject was able to perform tasks which were not possible before, such as carrying a basket with weights, highlighting the enhanced functionality provided by the orthosis. In brief, by addressing the limitations of existing devices, this novel powered myoelectric elbow orthosis offers individuals with neuromuscular injuries/conditions improved quality of life. Further research will expand the patient population and control mechanisms.