Search Results (455)

This paper presents a comparative study of the applicability and accuracy of optimal control methods and neural-network-based estimators in the context of porkchop plots for preliminary asteroid rendezvous mission design. The scenario considered involves a deep-space CubeSat equipped with a low-thrust engine, departing from Earth and rendezvousing with a near-Earth asteroid within a three-year launch window. A low-thrust trajectory optimization model is formulated, incorporating variable specific impulse, maximum thrust, and path constraints. The optimal control problem is efficiently solved using Sequential Convex Programming (SCP) combined with a solution continuation strategy. The neural network framework consists of two models: one predicts the minimum fuel consumption ($\Delta v$), while the other estimates the minimum flight time ($\Delta t$) which is used to assess transfer feasibility. Case results demonstrate that, in simplified scenarios without path constraints, the neural network approach achieves low relative errors across most of the design space and successfully captures the main structural features of the porkchop plots. In cases where the SCP-based continuation method fails due to the presence of multiple local optima, the neural network still provides smooth and globally consistent predictions, significantly improving the efficiency of early-stage asteroid candidate screening. However, the deformation of the feasible region caused by path constraints leads to noticeable discrepancies in certain boundary regions, thereby limiting the applicability of the network in detailed mission design phases. Overall, the integration of neural networks with porkchop plot analysis offers an effective decision-making tool for mission designers and planetary scientists, with significant potential for engineering applications. Full article

Background: Sleep disturbances are common in dementia and adversely affect both the person with dementia and their caregiver. Non-pharmacological options exist but are seldom dyadic or culturally tailored, limiting their reach and relevance across diverse communities. Objective: We aimed to co-develop DREAM (Dyadic Resilience, Engagement, Awareness & Mind–body intervention)—an 8-week dyadic mind–body programme (mindfulness + gentle Tai Chi) for improving sleep and wellbeing in people with dementia and their caregivers. Methods: The process was informed by Intervention Mapping (Stages 1–4) and underpinned by established behaviour change frameworks, including the Behaviour Change Wheel (BCW), the COM-B model (Capability, Opportunity, Motivation → Behaviour), and the Theoretical Domains Framework (TDF), to systematically identify determinants of engagement. Co-design involved dementia–caregiver dyads, Patient and Public Involvement (PPI) contributors, clinicians, mind–body practitioners, and community stakeholders. Results: The intervention was co-developed and culturally grounded through engagement with White British, Caribbean, Chinese, and South Asian communities. Participants reported high cultural resonance, endorsing DREAM’s concise practices, caregiver-supported home routines, and delivery in trusted community venues. Behavioural insights highlighted the importance of motivational framing (perceived dyadic benefits, cultural meaning), practical enablement (simplified guidance, prompts/cues, environmental restructuring), and caregiver facilitation to support adherence. Conclusions: DREAM demonstrates the practicability of using Intervention Mapping to co-develop a culturally responsive, theory-informed dyadic mind–body intervention for people with dementia and their caregivers. This groundwork supports progression to a feasibility trial focused on implementation processes and preliminary sleep and wellbeing outcomes. Full article

Objectives: To develop a simplified MRI-based shorthand assessment method, referred to as the Sagittal Tibial Epi-Physis (STEP) Shorthand, for skeletal age assessment in skeletally immature patients with anterior cruciate ligament (ACL) injuries. This study aimed to elaborate a single-plane MRI-based skeletal age estimation tool and to explore its feasibility and inter-rater reliability in comparison with existing MRI-based shorthands. Methods: This prospective study included 130 knee MRIs (79% males) from 97 skeletally immature patients (overall average age of 14.0 ± 2.1 years) with ACL injuries treated between February 2022 and January 2025. A new shorthand assessment method was developed based on sagittal T1-weighted MRI evaluation of the proximal tibial epiphysis. A validation cohort of 74 MRIs was independently evaluated by four raters with different levels of expertise using the STEP, Meza, and Politzer shorthand atlases. Inter-rater reliability (ICC), intra-rater agreement (Cohen’s kappa), and association with chronological age (Spearman rho) were calculated. Results: The STEP Shorthand tool demonstrated a strong association with chronological age (rho = 0.890, p < 0.001) with consistent associations across sex subgroups. Inter-rater reliability was high and comparable to established MRI-based shorthands. The use of a focused sagittal T1-weighted evaluation allowed for a simplified and reproducible assessment across raters with varying experience levels. Conclusions: The STEP Shorthand represents a pragmatic and reliable tool for MRI-based skeletal age assessment in pediatric and adolescent patients with ACL injuries. The STEP Shorthand can support timely decision-making in surgical planning and enhance standardization across different levels of clinical expertise. Full article

Introduction: Gestational diabetes (GD) screening remains limited in many low- and middle-income countries (LMICs) due to resource constraints, limited training, and low community awareness. Although community-centered approaches may improve access to screening in rural and Indigenous settings, the implementation processes through which such approaches are designed and operationalized are rarely documented. Methods: This study presents a community-based implementation process report describing the development, adaptation, and early implementation of a GD screening program in rural Guatemala, guided by the Exploration, Preparation, Implementation, and Sustainment (EPIS) implementation science framework. Using a participatory approach, international screening guidelines were systematically adapted to the local context through iterative protocol refinement, structured stakeholder engagement, and ongoing feedback from community health educators and partner institutions. Aggregate program data were used descriptively to characterize early screening uptake and feasibility. Results: Key implementation challenges included patient no-shows, community skepticism, and difficulties among health educators in interpreting screening procedures. Iterative adaptations were introduced to simplify protocols, reduce loss to follow-up, and strengthen community engagement. Over time, the program expanded from point-of-care screening to more comprehensive prenatal services and increased collaboration with the Ministry of Health and local community outlets. A total of 103 Indigenous Mayan Tz’utujil women were screened (mean age: 26.9 years; range: 15–46), of whom, 12 were diagnosed with GD. Conclusions: This implementation process report demonstrates the scientific value of systematically documenting real-world adaptation, feasibility, and stakeholder engagement when introducing GD screening in rural Indigenous LMIC settings. The implementation lessons described may inform similar maternal health initiatives in comparable contexts. Full article

Background/Objectives: Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has become the standard for diagnosing solid pancreatic masses (SPMs). However, in the absence of rapid on-site cytopathologic evaluation (ROSE), the optimal number of needle passes remains uncertain. This study aimed to evaluate the diagnostic performance of EUS-FNB using a gross-eyed evaluation with the fanning technique in patients with pancreatic malignancy. Methods: This retrospective single-center study included 140 patients with confirmed pancreatic malignancy who underwent EUS-FNB with at least three needle passes between January 2022 and December 2025. Gross-eyed visual inspection for whitish core tissue was used to assess the specimen adequacy. The primary outcome was the diagnostic rate of malignancy. The secondary outcomes included the tissue adequacy and yield rate of malignancy. Results: The diagnostic rate of malignancy improved with additional passes, 72.1% for one pass, 82.9% for two, and 90.7% for three. However, the gain beyond two passes was marginal. The tissue adequacy was high across all passes (≥94.3%), with most samples deemed adequate within two passes. The yield rate of malignancy similarly improved from 82.1% (one pass) to 91.4% (three passes). No adverse events were reported. Gross-eyed evaluation was feasible in all cases and guided effective sampling. Conclusions: EUS-FNB with two puncture numbers and the fanning technique achieves high diagnostic performance for pancreatic malignancy without the need for ROSE and MOSE. Two passes appear sufficient in most cases, supporting a simplified and safe approach that minimizes unnecessary needle passes. Full article

The reliability of high-strength bolted connections is critical to the safety of large-scale engineering structures. This study proposes a non-contact quantitative method for detecting bolt loosening based on the self-magnetic flux leakage (SMFL) effect. Systematic experiments were carried out on M14-12.9 bolts, using nine independent specimens tested under six torque levels, to reveal the intrinsic relationship between bolt preload and the “magnetic valley” feature of the surface leakage field. For quantitative evaluation, the absolute value of the differential peak magnetic field, |ΔPMF|, is defined as the core feature parameter. The results show that, in the reference specimen group, |ΔPMF| exhibits a pronounced linear relationship with the applied torque (R² > 0.96), and the corresponding linear regression parameters display good consistency across the nine specimens (RSD ≈ 4%). Comparative tests on two additional bolt specifications clarify how bolt strength grade and geometric size influence the detection sensitivity and linearity. To address lift-off effects, measurements on a representative specimen at four lift-off heights were used to construct a simplified bivariate linear compensation model, which significantly reduces lift-off-induced bias within the working range h = 10–16 mm. Finally, a hierarchical diagnostic scheme for bolt loosening that incorporates lift-off compensation is established on the basis of |ΔPMF|, providing a feasible approach for rapid assessment of bolt loosening under complex service conditions. Full article

Objective: To assess the effectiveness of a fixed contrast injection protocol—75 mL of contrast followed by 40 mL saline at 5 mL/s with an injection duration of 23 s—in achieving diagnostic enhancement in coronary CT angiography (CCTA) using 64-slice detector CT scanner. Materials and Methods: 456 consecutive patients with suspected coronary disease who underwent CCTA on a 64-slice detector CT scanner between January 2023 and December 2024 and were retrospectively enrolled. Each patient received 75 mL of contrast medium followed by 40 mL of saline at a flow rate of 5 mL/s, with a total injection duration of 23 s. Two radiologists, blinded to patient information, independently measured the contrast enhancement (HU) values in the coronary segments, ascending and descending aorta, and left ventricle. Attenuation levels ≥250 HU were considered diagnostic. Patients were grouped by body weight into two categories: Group 1 (≤75 kg) and Group 2 (>75 kg). The independent t-test and Mann–Whitney U test were used to compare HU values in each vessel between the two groups, while the Chi-square test was applied to compare enhancement success rates (HU ≥ 250) between the groups per vessel. Results: A total of 281 patients (mean age: 51.88 years ± 11.15 [SD]; 167 male, 114 female), were included. Statistically significant differences in the HU enhancement measurements were found between groups (p < 0.001–0.007). However, all segments showed mean and median HU values above 250 HU. Enhancement success rates were significantly higher in Group 1 (p = 0.005–0.04), except in the ascending aorta, descending aorta, left main coronary artery, middle right coronary, distal right coronary artery, and middle left circumflex artery, where the rates were statistically comparable between the groups (p = 0.054–0.61). Conclusions: A fixed contrast protocol (75 mL of contrast medium followed by 40 mL of saline at a 5 mL/s flow rate with a total injection duration of 23 s) appears to be feasible for achieving diagnostic contrast enhancement in CCTA using a 64-slice multidetector CT scanner. This protocol may offer a simplified alternative to individualized, weight-based contrast dosing strategies. Full article

Accurate brightness temperature (TB) measurements and microwave emissivity retrieval in passive microwave sensing conventionally rely on absolute radiometric calibration, which often requires additional hardware and complex procedures. Under well-defined geometric and environmental conditions, this study proposes a mirror-reflection-based method for measuring the microwave emissivity of flat scenes using ground-based radiometers without conventional absolute calibration. The method employs a simplified four-step observation sequence, in which the radiometer measures the pure flat scene, the flat scene with mirror reflection, the reference wall, and the cold sky. A geometric model is developed to determine the effective incidence-angle range, and an analytical framework is developed to evaluate retrieval accuracy. Numerical simulations are conducted to examine the effects of scene material, reference-wall property, operating frequency, polarization, and radiometric sensitivity. Outdoor experiments are further performed to assess feasibility under practical measurement conditions. The results show that, within moderate incidence-angle ranges and under stable radiometric conditions, the retrieved emissivities of flat scenes agree well with theoretical predictions. These findings indicate that the proposed mirror-reflection-based approach provides a feasible supplementary or alternative solution for emissivity estimation of flat targets in ground-based measurements when absolute calibration is unavailable or impractical, rather than a replacement for conventional calibration techniques. Full article

Background: Rate-dependent depression of the Hoffmann reflex (RDD-HR) is a neurophysiological marker of spinal inhibition altered in several neurological conditions, yet no consensus exists on optimal stimulation frequency, number of stimuli, or the feasibility of upper limb recordings. This study aimed to define practical, standardized parameters for reliable RDD-HR assessment in upper and lower limbs of healthy adults, as a first step toward clinical application. Methods: In this observational study, bilateral Hoffmann reflexes were recorded from the flexor carpi radialis and soleus muscles in 21 healthy adults. Stimulation was delivered using three 10-pulse trains at seven frequencies (0.1–5 Hz). RDD-HR was quantified as the median H-reflex area, expressed as a percentage of the first response (lower values indicate greater depression). Optimal frequencies and minimal stimuli were identified by sigmoid fitting and confidence analyses, with train and stimulus effects tested by two-way ANOVA. Results: RDD-HR displayed a sigmoidal frequency–response across all limbs. Maximal depression occurred at 1–5 Hz, with no significant differences between these frequencies, supporting 1 Hz as optimal. Depression was greater in lower limbs (~30%) than upper limbs (~47%). Reliable estimates were obtained using a single train of seven stimuli, with no benefit from averaging across trains. Upper limb recordings required lower stimulation intensities. Conclusions: RDD-HR can be reliably assessed using a simplified protocol based on a single seven-pulse train at two key frequencies. This standardized approach provides a methodological foundation for future clinical validation of RDD-HR as a biomarker of spinal inhibitory dysfunction. Full article

Efficient irrigation planning in data-scarce regions remains challenging due to limited access to localized meteorological data, reliance on complex computer-based models, and the technical knowledge required to deploy them at the field scale. Hence, the need for accessible, smartphone-based tools that simplify soil water balance calculations using public data to support practical decision-making in resource-limited contexts. This smartphone-based application estimates Net and Gross Irrigation Requirements using a Soil Water Balance (SWB) framework. The app combines region-specific empirical formulations for Effective Rainfall (Pe) calculation. The application utilizes user-supplied crop and irrigation parameters and meteorological data available in the public domain and operates at multiple temporal scales (daily, 10-day, weekly, and monthly), thereby supporting flexible irrigation schedules. The performance of app was evaluated through simulation-based benchmarking against FAO-CROPWAT 8.0 using harmonized inputs across five representatives agro-climatic region: Central India, Southern Vietnam, Northern Thailand, Western Bangladesh, and Central Sri Lanka. Quantitative comparison showed deviations within ±5% for Effective Rainfall, crop evapotranspiration, Net Irrigation, and Gross Irrigation, and low mean bias values (−2.8% to +3.3%) show the absence of systematic over- or under-estimation compared to CROPWAT model. The application also demonstrated responsiveness to climatic variability. Although the validation is limited to few representative locations and assumed minimal runoff conditions, the results suggest that the proposed method is technically consistent and feasible in practice. This study demonstrates smartphone-based application as a decision support for field-level irrigation planning and water resource management, particularly in data-limited agricultural contexts. Full article

With the cost-saving benefits of reusable launch vehicles (RLVs), South Korea is pursuing the application of reusability technologies to KSLV-III. While SpaceX currently reuses only the first stage of Falcon 9, the Starship program aims for full-stage recovery, motivating further examination of second-stage reuse. This study extends the scope of the analysis to medium-class launch vehicles and evaluates the feasibility of second-stage reuse for two vehicle scales. The performance losses associated with three recovery methods—vertical landing, parachute, and fly-back—are quantitatively assessed using conceptual-level recovery system design and simplified mass modeling. For KSLV-III, a conceptual expendable medium-class launch vehicle capable of delivering a 10-ton payload to a 200 km low Earth orbit (LEO) was designed using an algebraic modeling approach. Based on this reference design, the recovery methods were evaluated for both medium-class and super-heavy-class vehicles. Results of the present order-of-magnitude conceptual trade study show that, for medium-class vehicles, the parachute provides the highest performance, followed by fly-back, while vertical landing yields the lowest. For super-heavy vehicles, the parachute remains the most effective, but vertical landing becomes the second-best option, with fly-back exhibiting the lowest performance. As the vehicle scale increases, parachute effectiveness declines, fly-back performance improves, and vertical landing shows the greatest performance gains. However, parachute becomes impractical for super-heavy vehicles due to structural limitations, making vertical landing the most viable option. In contrast, medium-class vehicles do not necessarily require vertical landing, and the optimal recovery strategy should be chosen based on vehicle structural characteristics and mission objectives. This study provides insights that support the selection of efficient recovery strategies during the early design phase of RLVs. Full article

Background/Objectives: Balloon eustachian tuboplasty (BET) is an effective surgical option for obstructive eustachian tube dysfunction (OETD). However, the feasibility of performing BET under local anesthesia (LA) using simplified analgesic protocols remains underexplored. We examined the feasibility of a streamlined LA-BET protocol. Methods: Fifty patients (sixty-four ears) diagnosed with primary OETD between March 2024 and December 2025 were enrolled. All patients underwent BET under LA using intramuscular ketorolac and topical lidocaine gel without sedation or nerve blocks. Pain scores, blood pressure changes, and patient acceptance were analyzed for each patient; Eustachian Tube Dysfunction Questionnaire-7 (ETDQ-7) scores, tympanogram types, and Valsalva results were analyzed for each ear. All outcome measures were assessed 3 months postoperatively. Results: The mean ETDQ-7 score significantly improved from 24.9 ± 7.4 to 11.9 ± 5.4 (p < 0.001). The minimal clinically important difference (MCID ≥ 3.7) was achieved in 90.6% of ears, and normalization (ETDQ-7 ≤ 14.5) in 75.0%. The proportion of ears with positive Valsalva maneuvers increased from 39.1 to 76.6% (p < 0.01), and type A tympanograms improved from 64.1 to 84.4% (p = 0.018). Mean pain scores were 3.5 during insertion, 2.1 during balloon inflation, and 0.6 after deflation. All patients completed the procedure, and 96% would undergo LA again. Conclusions: LA-BET performed using intramuscular ketorolac and topical lidocaine gel is safe, tolerable, and effective. This protocol provides symptom relief and functional improvement without sedation or nerve block and offers a practical outpatient alternative for chronic OETD management. Full article

Background: Diagnosing peanut allergy (PA) in children without known exposure remains challenging due to the need to distinguish true clinical allergy from asymptomatic sensitization. This study aimed to evaluate the diagnostic performance of individual and combined in vitro markers, particularly sIgE to Ara h 2, and to develop a multistage decision pathway that may reduce reliance on oral food challenge (OFC). Methods: Eighty children with suspected peanut allergy were prospectively enrolled. All participants, including healthy controls, underwent skin prick testing (SPT), measurement of sIgE to peanut and Ara h 2, and basophil activation testing (BAT). A multistage diagnostic algorithm incorporating these markers was constructed, and its performance was assessed using ROC analysis, predictive values, and likelihood ratios. A secondary analysis evaluated a simplified decision pathway excluding BAT. Results: sIgE to Ara h 2 demonstrated excellent individual performance (AUC 0.889), with 96.6% PPV at the optimal cut-off. The full multistage decision pathway (SPT + sIgE + BAT when interpretable) achieved 100% specificity and avoided OFC in 28.6% of children. However, BAT feasibility was limited; over 25% of results were uninterpretable. The simplified decision pathway (SPT + sIgE to Ara h 2) preserved 100% specificity and enabled the avoidance of OFC in 27.5% of cases, with slightly lower sensitivity. Conclusions: A structured in vitro diagnostic approach using sIgE to Ara h 2 and SPT can reliably identify peanut allergy in selected pediatric patients, particularly those without a reliable peanut exposure history. BAT enhances specificity but should be considered a confirmatory tool due to feasibility limitations. Full article

Cardiovascular disease (CVD) remains the leading cause of death worldwide, accounting for nearly one-third of global mortality. Arterial stiffening, particularly in the central elastic arteries, impairs the Windkessel (cushioning and pumping) function and contributes to cardiovascular risk beyond traditional factors. Carotid–femoral pulse wave velocity (cfPWV) is established as the gold standard for assessing aortic stiffness and predicting cardiovascular and all-cause mortality; however, its technical complexity and requirement for trained personnel limit its use in routine clinical and community settings. These challenges have driven the development of simplified techniques for population screening, such as brachial–ankle PWV (baPWV). More recently, single-cuff oscillometric devices have emerged as practical alternatives. These methods are simple enough to be implemented in daily healthcare at home, thereby greatly enhancing accessibility, although their accuracy depends on model assumptions and calibration. In this perspective article, we highlight the pathophysiological significance of preserving the central arterial Windkessel function and emphasize the need for its practical assessment. Recent innovations mark a paradigm shift from complex laboratory-based measurements toward simplified, data-driven, and socially feasible screening tools for the early detection and prevention of CVD. Full article

Circuit implementation is a widely accepted method for validating theoretical insights observed in chaotic systems. It also serves as a basis for numerous chaos-based engineering applications, including data encryption, random number generation, secure communication, neuromorphic computing, and so forth. To get feasible, compact, and cost-effective circuit implementations of chaotic systems, the underlying mathematical model may be simplified while preserving all rich nonlinear behaviors. In this framework, this manuscript presents a simplified Hopfield Neural Network (HNN) capable of generating a broad spectrum of complex behaviors using a minimal number of electronic elements. Based on Shil’nikov’s theorem for heteroclinic orbits, the number of non-zero synaptic connections in the matrix weights is reduced, while simultaneously using only one nonlinear activation function. As a result of these simplifications, we obtain the most compact electronic implementation of a tri-neuron HNN with the lowest component count but retaining complex dynamics. Comprehensive theoretical and numerical analyses by equilibrium points, density-colored continuation diagrams, basin of attraction, and Lyapunov exponents, confirm the presence of periodic oscillations, spiking, bursting, and chaos. Such chaotic dynamics range from single-scroll chaotic attractors to double-scroll chaotic attractors, as well as coexisting attractors to transient chaos. A brief security application of an S-Box utilizing the presented HNN is also given. Finally, a physical implementation of the HNN is given to confirm the proposed approach. Experimental observations are in good agreement with numerical results, demonstrating the usefulness of the proposed approach. Full article