Search Results (4,570)

In this study, composite aerogels based on graphene oxide (GO) and melamine (MM), obtained by freeze-drying of hydrogels after ultrasonic treatment of aqueous suspensions, have been systematically studied for the first time. It was shown that the addition of melamine leads to an increase in the aerogel density from 12 to 22 mg/cm³, a change in its color, and the formation of a structure reminiscent of nacre. Using IR spectroscopy, Raman scattering, TGA, and DSC, it was established that during synthesis, partial reduction of GO, hydrolysis of sulfate groups, and strong intermolecular (including possible covalent) interactions between the components occur. The exothermic peak for GO aerogel (ΔH ~1480 J/g, ~220 °C) shifts to a lower temperature region in the composite. MM/GO composite aerogels demonstrate record sorption capacity for organic solvents (up to 86 g/g) and mineral-oil (66 g/g), significantly surpassing known analogs. A key limitation was identified—the leaching of melamine by water, which reduces water sorption by 15 times after the first cycle. The obtained materials can be considered promising for eliminating spills of organic liquids and petroleum products. Full article

Early detection of lung cancer remains challenging due to the extremely low concentrations of disease-specific biomarkers, which limit the development of highly sensitive and reliable point-of-care (PoC) diagnostic devices. Electrochemical biosensors integrating graphene oxide (GO) and gold nanoparticles (AuNPs) have emerged as promising platforms for the rapid, sensitive, and selective detection of lung cancer biomarkers, enabling more timely diagnosis. Biomarkers such as carcinoembryonic antigen (CEA), cytokeratin-19 fragments (CYFRA 21-1), neuron-specific enolase (NSE), and circulating tumour DNA are increasingly investigated for PoC applications since they can be detected in various biological fluids associated with lung cancer. Nanocomposite materials, particularly GO/AuNP hybrids, provide synergistic advantages by combining the large surface area and abundant functional groups of GO for stable immobilization of biorecognition elements with the excellent conductivity and bioconjugation capability of AuNPs that enhance signal transduction. This review critically discusses key biomarker targets for lung cancer, the properties of GO and Au in biosensing, and the role of AuNP/GO nanocomposites in improving biosensor performance. It further examines the application of electrochemical biosensors for lung cancer biomarker detection, highlighting recent developments. Additionally, the review outlines current challenges limiting clinical translation and PoC implementation, provides recommendations to address these barriers, and discusses future perspectives for improving the detection of low-abundance biomarkers for early lung cancer diagnosis. Ultimately, these technologies seem promising for the development of rapid diagnostic tools equivalent to established platforms such as lateral-flow immunoassays. Full article

This paper proposes a three-dimensional prescribed-time hierarchical cooperative guidance law (3-D PTHCGL) for rapid and reliable head-on encirclement in cooperative interception of high-speed targets under incomplete directed communication topology, target maneuvers, and limited terminal engagement time. The proposed method consists of a distributed estimator layer (DEL) and a local controller layer (LCL), addressing three key issues in head-on encirclement formation: information acquisition, rapid convergence, and geometric configuration. In the DEL, a distributed prescribed-time estimator (DPTE) is developed to enable followers without direct communication with the leader to estimate the leader’s states from neighborhood information within a prescribed time. In the LCL, a prescribed-time extended state observer (PTESO) and a three-dimensional prescribed-time cooperative guidance law (3-D PTCGL) are designed to estimate target-maneuver-induced disturbances and unknown states, and to guarantee prescribed-time convergence of estimation and cooperative tracking errors. Furthermore, virtual line-of-sight (LOS) angles are introduced based on a three-dimensional head-on interception kinematic model to characterize the head-on encirclement configuration, and range-to-go together with radial relative velocity are adopted instead of time-to-go to reduce sensitivity to time-estimation errors. Simulation results demonstrate the effectiveness and robustness of the proposed method in achieving prescribed-time head-on encirclement and simultaneous attack without a speed advantage. Full article

Millimeter-wave (mm-wave) near-field imaging using frequency-modulated continuous wave (FMCW) radar has emerged as a pivotal technology for high-resolution applications, including security screening, non-destructive testing, and medical diagnostics. This review evaluates the performance and evolution of key imaging algorithms, categorized into spatial-domain and frequency-domain frameworks. We analyze the delay-and-sum (DAS) beamformer for its real-time utility and the back-projection algorithm (BPA) for its baseline phase precision and robust adaptability to irregular scanning trajectories. To address the high computational demands of standard spatial-domain processing, we examine fast alternatives such as the range migration algorithm (RMA). The exact RMA leverages Fourier-domain operations and Stolt coordinate mapping to achieve optimal computational scaling on uniform grids while preserving diffraction-limited spatial resolutions. Concurrently, we evaluate fast spatial-domain approximations, including Fast Back-Projection (Fast-BPA), which introduces localized Taylor-series expansions to linearize near-field range paths within sub-apertures, accelerating voxel reconstruction times at a reduced computational cost. Furthermore, this study explores advanced modifications designed to overcome physical and operational constraints, such as motion-compensated matched filtering (MF) to eliminate the “stop-and-go” assumption in continuous scanning, and sparse multiple-input multiple-output (MIMO) configurations to mitigate aliasing in undersampled environments. Comparative analysis reveals that while spatial-domain methods (DAS/BPA) generally offer higher robustness to non-uniform aperture perturbations, frequency-domain migration pathways (RMA) maximize the computational throughput required for large-volume three-dimensional (3D) reconstructions. The findings demonstrate that achievable resolution is primarily governed by signal bandwidth and aperture synthesis, though practical performance is often limited by calibration errors and computational overhead. Collectively, these advancements validate the potential of mm-wave FMCW systems to achieve sub-millimeter 3D imaging, bridging the gap between theoretical diffraction limits and real-world indoor sensing challenges. Full article

Background/Objectives: The aim of this study was to assess the association between physical activity (PA), in accordance with the WHO recommendations for weekly activities, and the occurrence of falls over a one-year period. The study was conducted among 150 individuals aged 48 to 88 years living in the Polish city of Łódź during the Community Festive event. Methods: Data from 150 participants (131 women and 19 men) were assessed using the Tinetti scale, Time Up & Go (TUG), Hand Grip Strength (HGS), and a structured face-to-face interview regarding retrospective fall incidents over the past 12 months and the weekly volume of PA. Results: A total of 29 participants experienced a fall (all of whom were women) while 121 individuals reported no fall. In the non-fall group, higher percentage of individuals met the WHO physical activity guidelines compared to the fall group (74% vs. 61.1% to 48.3%). Furthermore, individuals without the history of falls achieved better results in the RHGS (p = 0.02) and Tinetti tests (p = 0.04). Notably, individuals in the fall group reported engaging in more aerobic activity on average than those in the non-fall group. Conclusions: The study demonstrated that older adults and middle-aged individuals without a history of falls reported a higher compliance with weekly resistance training. While multivariable models show that raw physical activity volume is not an independent predictor of fall risk, training compliance aligns with superior objective neuromuscular performance, showing positive associations with RHGS and Tinetti scores. Full article

Traditional methane sensors based on metal oxide semiconductors typically require high operating temperatures (200–400 °C), which not only leads to high power consumption but also often results in detection limits that struggle to fall below 5 ppm. To achieve room-temperature operation with lower detection limit, this work proposed a surface acoustic wave (SAW) methane sensor using monolayer graphene oxide (GO) film. The GO material was prepared by a modified Hummers method combined with liquid-phase exfoliation and characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The sensor was constructed by drop-casting the GO dispersion onto the delay line region of a Y-cut quartz SAW device. Results showed that the GO sensor exhibited a low detection limit of 1 ppm and a sensitivity of 0.046 mV/ppm in the range of 100–1000 ppm, which was 2.2 times higher than that of multilayer graphite (0.021 mV/ppm). The response and recovery times for 500 ppm methane were 16.7 s and 66.4 s, respectively. Good repeatability and selectivity were also demonstrated. This work presents a simple and effective approach for room-temperature methane detection using monolayer GO on SAW devices. Full article

Coating method significantly influences how graphene derivatives perform on textile fibers, especially blended substrates where fiber chemistry varies. Graphene oxide (GO) and GO/fullerene composites were deposited on a blended fabric (45% PET, 25% viscose, 8% elastane, 22% recycled PET) using doctor blade and dip coating, followed by chemical reduction to rGO. Three thickness levels were applied for each method: blade gap settings of 50, 100, and 150 µm for doctor blade coating, and immersion times of 30 s, 2 min, and 5 min for dip coating. A more concentrated, higher-viscosity GO dispersion was prepared for doctor blade coating. FTIR spectra showed spectral changes consistent with chemical reduction in GO, including attenuation of hydroxyl-related absorption bands. Electrical resistivity and mechanical properties were determined via conductivity measurements and tensile testing. Doctor blade coatings achieved 0.81 kΩ/sq for rGO/fullerene at the highest thickness, 27 to 70 times lower than dip-coated samples (22.1–56.9 kΩ/sq), depending on coating material and level. The difference reflects uniform blade deposition on hydrophobic polyester fibers, whereas immersion leads to uneven particle distribution. Fullerene addition reduced sheet resistance by approximately fivefold. Mechanical testing showed that coating did not degrade fabric integrity; elongation values remained above 70% across all samples, with most exceeding 80%. These results suggest that, under the present processing conditions, the lower sheet resistance was mainly related to the more continuous coating morphology obtained by doctor blade coating. Full article

Executive functions (EFs) are foundational for early learning and school readiness. Interventions that couple motor engagement with explicit cognitive demands may offer an efficient approach to support EFs during preschool years. This exploratory randomized controlled trial examined the preliminary effects of an 8-week Playful Physical Activities (PPA) program on EF and school readiness. Preschool children were randomized to (i) PPA, a structured program integrating executive challenges (response inhibition, working memory, and planning) into movement games, or (ii) an active control receiving the regular physical education curriculum (3 sessions/week, 60 min/session, 8 weeks). Outcomes were assessed before and after the intervention and included Go/No-Go error rate, BVMT-R immediate and delayed recall, RCFT copy score, and school readiness domains (mathematical, linguistic, and social competence). Group × Time effects were tested using mixed ANOVA and summarized with partial eta squared (η²p). Between-group post-test differences were quantified using Hedges’ g. PPA was associated with greater pre-to-post improvements relative to control in attentional control/inhibition (Go/No-Go errors: η²p = 0.134; g = −1.78) and visuospatial organization/planning (RCFT copy: η²p = 0.307; g = 1.36). Visuospatial memory outcomes showed very large interaction effects (BVMT-R immediate η²p = 0.937, g = 5.14; delayed η²p = 0.854, g = 4.10), but these values are exploratory and should not be emphasized as the primary evidence for cognitive improvement because the BVMT-R was used as a non-normed raw-score index outside its validated age range in this preschool sample. School readiness indicators showed favorable changes across mathematical, linguistic, and social competence (η²p = 0.514, 0.385, and 0.337; g = 1.95, 2.05, and 1.31, respectively). Overall, these preliminary findings suggest that cognitively enriched movement may support EF-related performance and school-readiness indicators, but they should not be interpreted as definitive proof of efficacy. Larger prospectively registered trials with balanced groups, age-appropriate outcome measures, and stronger fidelity documentation are needed before firm recommendations can be made. Full article

Railway transport management has changed dramatically over the past 50 years. The advent of computer technology and the capacity for information transmission brought greater safety and the ability to remotely control interlocking devices. These enable the centralisation of railway transport management, leading to higher operational efficiency and reduced staffing costs. At the same time, this technological progress has enabled the development of additional automation functions, which we can abbreviate as ARS (Automated Route Setting). The international designation Automatic Route Setting (ARS) includes actions that enable the automation tool to execute instructions to the signal box without the intervention of operating personnel (the dispatcher). Their importance increases with line speed and the size of the remotely controlled area. Thanks to them, the dispatcher gains time because the ARS can automatically resolve some operational situations or allow the dispatcher to address them in advance, thereby distributing the workload over a wider time window. However, the interlocking system itself remains the primary safety mechanism and will prevent ARS if any element of the infrastructure is occupied. At the same time, it is not possible to automate safety-critical functions that require direct assistance from the operating personnel. In the article, the authors analysed functions in which ARS is currently widely used. In the next part, they focused on the possible expansion of the palette of these functions that could be included in the ARS regime using multi-criteria analysis. The WSA method was applied using data obtained from routine users of the system. This approach enabled the incorporation of practical operational experience into the evaluation process and provided an empirical basis for assessing and prioritising the analysed functions. The next step was a safety-critical analysis and determination of the conditions under which they could be included in the ARS regime. The safety-critical functions are left aside. It is assumed that these will still have to be performed by the operator, not by the ARS. Detailed implementations and quantification of their impacts on the dispatcher’s activities are then carried out for selected ARS functions. The analysis therefore yields a prioritised ranking of ARS functions, indicating the order in which their implementation would be most appropriate from an operational perspective. This ranking provides a systematic basis for the phased deployment of ARS functionalities, considering their expected operational benefits and practical applicability in railway traffic management. The last part of the article is a look into the future, because the development in the field of safe communication between the train and the infrastructure (V2I) and the transmission of valid information provides many new challenges not only in the field of ARS itself, but also in the optimisation of the entire process of managing and organising rail transport. If we can use the ARS functions today, it is only a matter of technical development to be able, for example, to guide trains to the exact time when a train route will be built for this train. This will also enable optimising the train’s energy consumption and tracking capacity use. The ideal state is when the infrastructure fully communicates with the train in GoA4 mode and optimises both the train’s ride and the use of the infrastructure. Full article

Post-earthquake structural inspections are critical for public safety and recovery, yet traditional manual assessments are slow, hazardous, and resource-intensive. This paper proposes a novel system that integrates a quadrupedal robot with a deep learning (DL) vision model to rapidly detect structural cracks and damage in the aftermath of earthquakes. A Unitree Go2 quadruped robot, equipped with cameras and sensors, is paired with a YOLOv8 instance segmentation network for near-real-time crack detection and localization. The approach addresses key limitations of manual post-disaster inspections by enabling operator-supervised, near-real-time visual crack screening in hazardous or hard-to-reach areas. The YOLOv8 model is trained on a curated dataset of crack and damage images to support crack detection and segmentation performance, and its advanced segmentation capabilities allow precise delineation of damaged regions. The integrated system is validated on a laboratory-scale concrete–steel frame with simulated damage. Preliminary results demonstrate that the Unitree Go2 quadruped robot can navigate and inspect structural elements while the AI model identifies and segments cracks and surface damage under near-real-time laboratory operating conditions. This work highlights the potential of combining advanced legged robotics and state-of-the-art DL for structural health monitoring (SHM), offering a preliminary visual screening tool that can support operator awareness and help prioritize areas requiring expert structural inspection. Full article

Geosynchronous spaceborne–airborne frequency-modulated continuous-wave bistatic synthetic aperture radar (GEO SA FMCW BiSAR) offers cost-effective and persistent target monitoring. However, both the maneuvers of the receiver during the signal propagation delay and the continuous movements of the radar platforms within the sweep complicate the received echo signal. These factors invalidate the “stop-and-go” assumption, which presumes constant-velocity motion. This paper proposes an echo model that simultaneously considers intra-pulse motion and accelerated motion of the high-maneuvering receiver. The introduction of receiver acceleration leads to nonlinear range terms in the bistatic range history, which will degrade the focusing performance if not properly compensated. Since the acceleration term is a small second-order quantity relative to the time delay, it is approximated by segmenting the aperture and applying the “stop-and-go” assumption within each sub-aperture. After dechirp, the two-dimensional (2-D) spectrum for imaging is derived by applying the principle of stationary phase and determining the azimuth stationary phase point via series reversion. Finally, imaging is achieved by azimuth compression, range cell migration correction, and secondary range compression. Simulation results demonstrate that the proposed algorithm achieves well-focused images while maintaining computational efficiency. Full article

Introduction: Community-based day center programs may support healthy ageing by promoting functional ability, mental well-being, and social participation among older adults, but real-world evidence from Latin America remains limited. Objective: We aimed to examine changes in functional status, mental health, and quality of life among older adults participating in the CEDIAM program in the Maule Region of Chile in 2022 and 2023. Methods: Pre–post observational study using routinely collected data from 15 CEDIAM centers. The 2022 and 2023 datasets were analyzed as independent cohorts. Functional status was assessed with the Barthel Index, the Lawton and Brody scale, and the Timed Up and Go test; mental health with the Mini-Mental State Examination and the 15-item Geriatric Depression Scale; and quality of life with the EuroQol-5D visual analogue scale. Paired comparisons, category-transition analyses, and multivariable logistic regression models of improvement were performed. Results: Baseline samples included 894 participants in 2022 and 897 in 2023. In 2022, all continuous outcomes improved significantly (all p ≤ 0.001). In 2023, the Barthel Index, the Timed Up and Go test, and the Geriatric Depression Scale improved (all p < 0.0001), and the EuroQol-5D visual analogue scale also improved (p < 0.01), whereas the Lawton and Brody scale (p = 0.204) and the Mini-Mental State Examination (p = 0.725) did not. Category-transition analyses showed significant improvements in basic activities of daily living and mobility in both cohorts (both p < 0.001), while significant categorical changes in instrumental activities of daily living, global cognition, depressive symptoms, and self-rated quality of life were observed only in 2022 (all p ≤ 0.01). Rural residence was associated with higher odds of improvement in basic activities of daily living (OR 1.62, 95% CI 1.17–2.25; p = 0.004), whereas age ≥75 years was associated with lower odds of improvement in depressive symptoms (OR 0.56, 95% CI 0.41–0.76; p < 0.001) and self-rated quality of life (OR 0.65, 95% CI 0.45–0.94; p = 0.023). Conclusions: Participation in CEDIAM was associated with favorable changes, particularly in basic functional status and mobility, although responses varied across outcomes and participant subgroups. Full article

Objectives: Human milk composition changes across lactation, but paired within-subject proteomic analyses comparing longitudinal trajectories in term and preterm milk remain limited. We aimed to characterize stage-associated proteomic changes within each cohort and determine whether longitudinal remodeling is shared or divergent between term and preterm lactation. Methods: In this single-center prospective study conducted at the Neonatal Intensive Care Unit, Jagiellonian University Medical College, Kraków, Poland (October 2020–November 2021), 40 lactating mothers (20 preterm, <32 weeks’ gestation, mean age 29.4 ± 6.1 years; 20 term, 37–42 weeks, mean age 30.2 ± 5.5 years) provided paired milk samples at ≤10 days postpartum and week 5. Milk serum proteomes were analyzed by quantitative data-independent acquisition mass spectrometry; differential abundance was assessed using two-sample t-tests with Storey false discovery rate correction (q < 0.05) and fold-change >1.5, followed by ClueGO pathway enrichment. Results: Stage-associated differential abundance was identified for 108 proteins in term milk (58 increased, 50 decreased) and 103 in preterm milk (64 increased, 39 decreased). Of these, 87 were shared between cohorts (80.6% of term, 84.5% of preterm set) with concordant directionality. Shared upregulated pathways included oxidative stress response and glycolysis (e.g., PRDX5, fold change 2.49, q = 0.044); shared downregulated pathways related to mucosal immunity (e.g., tenascin, fold change 9.61–11.41, q < 0.0001). Cohort-specific pathway signals were limited relative to shared remodeling. Conclusions: The human milk serum proteome undergoes substantial longitudinal remodeling in both term and preterm lactation, with most changes following a common temporal pattern; prematurity-related differences appear selective rather than global. These findings support lactation stage as a key determinant of milk proteomic composition and underscore the value of longitudinal, stage-aware study designs, although formal time-by-group interaction testing was not performed. Full article

Falls among older adults are a major public health concern due to their association with functional decline and increased healthcare utilization. This study investigated factors associated with fall occurrence by comparing older adults enrolled in a community-based physical activity program with sedentary older adults. This observational cross-sectional study included 67 older adults: 35 participants enrolled in the Niterói 60 Up program (G60UP; 68 ± 4 years) and 32 sedentary older adults in a sedentary comparison group (SCG; 70 ± 7 years). Assessments included anthropometric measurements, medication use, Timed Up and Go (TUG), Tinetti Performance-Oriented Mobility Assessment, Mini-Mental State Examination (MMSE), Pittsburgh Sleep Quality Index (PSQI), and orthostatic testing. Compared with the SCG, G60UP participants reported fewer falls during the previous year (0.26 ± 0.51 vs. 0.78 ± 0.83; p = 0.005), higher Tinetti scores (24.51 ± 2.54 vs. 18.28 ± 5.94; p < 0.001), shorter TUG times (8.66 ± 1.63 vs. 13.00 ± 4.31; p < 0.001), higher MMSE scores, better sleep quality (lower PSQI scores), and lower blood pressure and abdominal adiposity indicators. In the total sample, fall occurrence was associated with lower Tinetti scores (ρ = −0.416; p < 0.001), longer TUG times (ρ = 0.321; p = 0.008), older age (ρ = 0.328; p = 0.007), higher Conicity Index (ρ = 0.281; p = 0.021), and poorer sleep quality (ρ = 0.243; p = 0.047). No variable remained independently associated with falls in the exploratory multivariable logistic regression model. Participants enrolled in the 60 Up program presented more favorable functional, cognitive, sleep-related, and health-related profiles than those in the SCG. Due to the cross-sectional design, these findings should be interpreted as associations rather than causal relationships. Full article

Introduction: Coronary artery bypass grafting (CABG) in patients with chronic kidney disease/chronic renal failure (CKD/CRF) poses additional surgical risk, both perioperatively and beyond, compared to their non-renal failure counterparts. Patients with end-stage renal disease (ESRD) are at particularly high risk for complications with prognoses limited by cardiovascular (e.g., myocardial infarction, heart failure, stroke) and non-cardiovascular (e.g., infection) conditions associated with the disease itself and the treatment of it (i.e., dialysis). For decades, cardiac surgeons have continued to offer CABG to patients with ESRD on dialysis with variable success. The purpose of this report is to describe a relatively contemporary analysis of CABG surgery in ESRD patients utilizing a pump-assisted beating-heart technique with the analysis of and comparison to outcomes reported by other investigators as well as predictions generated by the Society of Thoracic Surgery outcome tool. We report both short- and intermediate-term outcomes. Methods: From 1 January 2019 through 31 May 2025, the data from all consecutive patients undergoing BH-CABG at a single institution by a single surgeon were collected. Demographic information as well as a preoperative risk assessment was performed using the Society of Thoracic Surgeon (STS) Risk Assessment tool. The BH-CABG was performed via median sternotomy with maintenance of normothermia and ventilation throughout the case. Postoperative outcomes were recorded including mortality, major morbidity, and length of stay (LOS). Hospital/operative results were compared to the STS risk calculations. On-going intermediate-term follow-up beyond the index hospitalization was completed using direct or indirect methods (i.e., clinic, telephone, email). Results: There were 439 BH-CABG patients during the study period. Fifty-nine patients (13.4%) had ESRD on HD. There were 39 men and 20 women with a mean age of 61 years (41–76 years). Fifty-one (86%) underwent pump-assisted BH-CABG (PADCAB) and eight patients underwent complete off-pump BH-CABG (OPCAB). The mean ejection fraction (EF) was 48% (15–70%). The mean number of grafts was 2.3 (1 to 4) and the mean cardiopulmonary bypass (CPB) time for the PADCAB cases was 80 min (34 to 118 min). Patient presentation consisted of the following: one with cardiogenic shock, one with cardiac arrest, two with STEMI, 18 with NSTEMIs, 10 with CHF, five with NSTEMI/CHF, six with unstable angina (USA), and 16 with a positive stress test in preparation for renal transplant consideration. There was one operative mortality (1.7%), one stroke (1.7%), no reoperation for bleeding, no deep sternal wound infection, one prolonged ventilation (1.7%), and one prolonged length of stay (1.7%); overall mortality/morbidity was 5.1%. Comparatively, the STS-predicted mortality was 5.7%, stroke 2.2%, reoperation for bleeding 3.5%, deep sternal wound infection 0.6%, prolonged ventilation 17.8%, prolonged LOS 14.8%, and combined mortality/morbidity 26.8%. Thirty-six of the 59 patients remained alive (61%) in the follow-up period. Twenty-three patients expired (39%) in the follow-up: 11 of cardiac issues, eight of sepsis, two of stroke, one of gastrointestinal issues, and one of cancer. The average duration of survival for expired patients was 2.28 years (13 days to 5 years and 4 months). Nine patients (15%) underwent renal transplantation and six of them remained alive (67%). Conclusions: CABG surgery in patients with ESRD is complicated with historically high mortality and morbidity. The results of this study demonstrate significant improvement in the reduction in hospital mortality and morbidity. However, intermediate-term outcomes remain poor with a preponderance of cardiovascular and infectious deaths. A trend toward improved intermediate-term outcomes appears in patients in whom CABG surgery was performed for purposes of renal transplantation. Full article