Search Results (694)

A principled, model-agnostic framework for structural feature extraction in time series is presented, grounded in topological data analysis (TDA). The motivation stems from two gaps identified in the literature: First, compact and interpretable representations that summarise the global geometric organisation of trajectories across scales remain scarce. Second, a unified, task-agnostic protocol for evaluating structure preservation against established non-topological families is still missing. To address these gaps, time-delay embeddings are employed to reconstruct phase space, sliding windows are used to generate local point clouds, and Vietoris–Rips persistent homology (up to dimension two) is computed. The resulting persistence diagrams are summarised with three transparent descriptors—persistence entropy, maximum persistence amplitude, and feature counts—and concatenated across delays and window sizes to yield a multiscale representation designed to complement temporal and spectral features while remaining computationally tractable. A unified experimental design is specified in which heterogeneous, regularly sampled financial series are preprocessed on native calendars and contrasted with competitive baselines spanning lagged, calendar-driven, difference/change, STL-based, delay-embedding PCA, price-based statistical, signature (FRUITS), and network-derived (NetF) features. Structure preservation is assessed through complementary criteria that probe spectral similarity, variance-scaled reconstruction fidelity, and the conservation of distributional shape (location, scale, asymmetry, tails). The study is positioned as an evaluation of representations, rather than a forecasting benchmark, emphasising interpretability, comparability, and methodological transparency while outlining avenues for adaptive hyperparameter selection and alternative filtrations. Full article

The production and assembly of large engineering structures, many requiring tight tolerances, demand accurate long-distance measurements. This poses a major challenge for metrologists across industries such as energy, aviation, automotive, and machinery. Contact measurements provide high accuracy but are slow, as tactile probes must be moved over large distances. Optical methods are much faster, yet their effective range is usually limited to a few meters, and they generally offer lower accuracy. Measurements of large-scale components are further complicated by varying environmental conditions (e.g., temperature gradients) and the accumulation of different error sources, making high-accuracy measurements difficult to achieve. These challenges motivated the authors to develop hybrid measurement systems (HMS) and methods for improving their accuracy. This paper describes the steps taken to build an HMS combining a large-volume, high-accuracy coordinate measuring machine with a structured-light scanner. It also presents a dedicated method for determining measurement uncertainty in HMS, based on a multiple-measurement strategy. A series of tests were performed on material standards with various shapes, dimensions, and geometric features, using both contact and optical systems. The measurement uncertainties were then evaluated using the developed method. Finally, the method was validated through tests conducted on a selected large-scale engineering object. Full article

Background/Objectives: First row transition metal ions have recently regained attention in coordination chemistry as alternatives to gadolinium-based paramagnetic contrast agents, motivated by emerging safety concerns associated with certain Gd³⁺-based contrast agents. In this study, we report the development of a novel homoleptic diketonate Fe³⁺ complex functionalized with biocompatible indole moieties. We investigate its potential as a paramagnetic relaxation agent by evaluating its ability to modulate the T₁ and T₂ relaxation times of water proton. Methods: Iron(III) tris-1,3-(1-methylindol-3-yl)propanedionate [Fe(BIP)₃] was synthesized via a thermal method from bis(1-methylindol-3-yl)-1,3-propanedione (HBIP) using Fe(ClO₄)₃∙6 H₂O as the metal source. The complex was characterized by UV-Vis, IR and NMR spectroscopy, differential scanning calorimetry–thermogravimetric analysis, and single-crystal X-ray diffraction. Fe(BIP)₃ aggregation behavior in aqueous environment, including size and morphology of aggregates, was investigated using dynamic light scattering and scanning electron microscopy. Incorporation of the aggregates into phospholipid vesicles was evaluated by fluorescence resonance energy transfer and fluorescence correlation spectroscopy. The paramagnetic properties of monomeric Fe(BIP)₃ were probed in solution by nuclear magnetic resonance recurring to the Evans bulk magnetization method. Results: The designed synthetic procedure successfully afforded Fe(BIP)₃, which was fully characterized by UV-Vis and IR spectroscopy, as well as single-crystal X-ray diffraction. Aqueous solutions of Fe(BIP)₃ spontaneously formed rice-grain-shaped nanoscale aggregates of hydrodynamic radius ≈ 30 nm. Incorporation of these aggregates into phospholipid vesicles enhanced their stability. The longitudinal r₁ and transverse r₂ relaxivities of Fe(BIP)₃ aggregates were assessed to be 1.92 and 52.3 mM⁻¹s⁻¹, respectively, revealing their potential as paramagnetic relaxation agents. Conclusions: Fe(BIP)₃ aggregates, stabilized through incorporation into phospholipid vesicles, demonstrate promising potential as novel paramagnetic relaxation agents in aqueous environments. Full article

This paper presents a dual four-port circularly polarized (CP) MIMO antenna based on substrate integrated waveguide (SIW) technology for sub-6 GHz applications. The design consists of two identical four-port SIW-based CP-MIMO antennas arranged in a mirror-symmetric configuration with an air gap of 15 mm. Each antenna employs four symmetrically arranged cross-shaped SIW patches excited by coaxial probes. Bidirectional radiation is achieved by applying a 180° phase difference between corresponding ports of the mirror symmetric configuration, referred to as the Backward-Radiating Unit (BRU) and the Forward-Radiating Unit (FRU). The bidirectional radiation mechanism is supported by array-factor-based theoretical modelling, which explains the constructive and destructive interference under phase-controlled excitation. To ensure high isolation and stable polarization performance, the antenna design incorporates defected ground structures, inter-element decoupling strips, and vertical metallic vias. Simulations indicate an operating band from 5.1 to 5.4 GHz. Measurements show a −10 dB bandwidth from 5.25 to 5.55 GHz, with the frequency shift attributed to fabrication tolerances and measurement uncertainties. The antenna achieves inter-port isolation better than −15 dB. A 3 dB axial-ratio bandwidth is maintained across the operating band. Measured axial-ratio values remain below 3 dB from 5.25 to 5.55 GHz, while simulations predict a corresponding range from 5.1 to 5.4 GHz. The proposed configuration achieves a peak gain exceeding 4 dBi and maintains an envelope correlation coefficient below 0.05. These results confirm its suitability for CP-MIMO systems with controlled spatial coverage. With a physical size of 0.733λ₀ × 0.733λ₀ per array, the proposed antenna is well-suited for vehicular and space-constrained wireless systems requiring bidirectional CP-MIMO coverage. Full article

The integration of complementary metal–oxide–semiconductor (CMOS) and micro-electromechanical systems (MEMSs) technologies for miniaturized biosensor fabrication enables unprecedented spatiotemporal resolution in monitoring the bioelectrical activity of the nervous system. Wafer-level CMOS technology incurs high costs, but multi-project wafer (MPW) runs mitigate this by allowing multiple users to share a single wafer. Still, monolithic CMOS biosensors require specialized surface materials or device geometries incompatible with standard CMOS processes. Performing MEMS post-processing on the few square millimeters available in MPW dies remains a significant challenge. In this paper, we present a MEMS post-processing workflow tailored for CMOS dies that supports both surface material modification and layout shaping for intracortical biosensing applications. To address lithographic limitations on small substrates, we optimized spray-coating photolithography methods that suppress edge effects and enable reliable patterning and lift-off of diverse materials. We fabricated a needle-like, 512-channel simultaneous neural recording active pixel sensor (SiNAPS) technology based neural probe designed for integration with optical fibers for optogenetic studies. To mitigate photoelectric effects induced by light stimulation, we incorporated a photoelectric shield through simple modifications to the photolithography mask. Optical bench testing demonstrated >96% light-shielding effectiveness at 3 mW of light power applied directly to the probe electrodes. In vivo experiments confirmed the probe’s capability for high-resolution electrophysiological measurements. Full article

Background: Pulmonary infarction (PI) is the result of the occlusion of distal pulmonary arteries resulting in damage to downstream lung areas that become ischemic, hemorrhagic, or necrotic, and it is often a complication of an underlying condition such as pulmonary embolism (PE). Since in most of cases it is located peripherally, lung ultrasound (LUS) can be a good evaluation tool. The typical radiological features of PI are well-known; however, there are limited data on its sonographic characteristics and its evolution. Methods: The aim of this study is to evaluate, using LUS, a convenience sample of patients with acute PE with computed tomography (CT) consolidation findings consistent with PI. Patients’ clinical characteristics were collected and LUS findings at baseline and their short-term progression was assessed. LUS was performed within 72 h of PE diagnosis (T0) and repeated after one (T1) and four weeks (T2). Each procedure started with a focused examination of the areas of lesions based on CT findings, followed by an exploration of the other posterior and lateral lung fields. The convex probe was used for initial evaluation integrating LUS evaluation with the linear one was employed for smaller and more superficial lesions and when appropriate. Color Doppler mode was added to study vascularization. Results: From June to October 2023, 14 consecutive patients were enrolled at the Respiratory Unit of the University Hospital of Pisa. The main population characteristics included the absence of respiratory failure and prognostic high-risk PE (100%), the absence of significant comorbidities (79%), and the presence of typical symptoms, such as chest pain (57%) and dyspnea (50%). The average number of consolidations per patient was 1.4 ± 0.6. Follow-up LUS showed the disappearance of some consolidations and some morphological changes in the remaining lesions: the presence of hypoechoic consolidation with a central hyperechoic area (“bubbly consolidation”) was more typical at T1 while the presence of a small pleural effusion often persisted both at T1 and T2. A decrease in wedge/triangular-shaped consolidations was observed (82% at T0, 67% at T1, 24% at T2), as was an increase in elongated shapes, representing a residual pleural thickening over time (9% at T0, 13% at T1, 44% at T2). A reduction in size was also observed by comparing the mean diameter, long axis, and short axis measurements of each consolidation at the three different studied time points: the average of the short axes and the median of the mean diameters showed a statistically significant reduction after four weeks. Additionally, a correlation between lesion size and pleuritic pain was described, although it did not achieve statistical significance. Conclusions: Patients’ clinical characteristics and ultrasound features are consistent with previous studies studying PI at PE diagnosis. Most consolidations detected by LUS change over time regarding size and form, but a minority of them do not differ. LUS is a safe and non-invasive exam that could help to improve patients’ clinical approach in emergency rooms as well as medical and pulmonology settings, clinically contextualized for cases of chest pain and dyspnea. Future studies could expand the morphological study of PI. Full article

Background: Intrachromosomal rearrangements in birds play a subtle but important role in shaping genomic evolution, phenotypic diversity and speciation. However, the avian sex chromosome system (homogametic ZZ males; heterogametic ZW females) remains relatively understudied, and evolutionary rearrangements of the Z chromosome have not been mapped in most species. To address this, we employed universally hybridizing avian Z chromosome probes to metaphases of 11 avian species from South America. Methods: Chromosome preparations were obtained from fibroblast cell cultures of 11 birds representing nine different orders; four bacterial artificial chromosome (BAC) probes were used in our interspecies fluorescence in situ hybridization (FISH) experiments. We identified chromosomal rearrangements in the species investigated, tracing the evolution of the Z chromosome in these species through comparison with reptiles from Southeast Asia (three snake species used as an outgroup), along with two reference species: chicken (Galliformes) and zebra finch (Passeriformes). Results: We observed high rates of intrachromosomal rearrangements in the avian Z chromosome, with most species showing different patterns from chicken and zebra finch. Nannopterum brasilianum (Suliformes) and Jacana jacana (Charadriiformes) showed the same BAC order as chicken, but centromere repositioning was evident. Apart from Piciformes, all other species exhibited a conserved Z chromosome size. The corresponding Z chromosome sequences were homologous to regions of the long arms of Chromosome 2 and W in snakes but not on the Z chromosomes. Conclusions: Comparative analysis of the Z chromosome across avian orders provides important insights into the dynamics of avian sex chromosomes and the evolution of sex chromosome systems in general. Full article

Background/Objectives: Multimodal large language models (LLMs) may directly interpret medical images, including thyroid ultrasounds (USs). Whether these models can reliably assess thyroid nodules—where subtle echogenic and morphological details are critical—remains uncertain. The American College of Radiology (ACR) TI-RADS system provides a structured framework for benchmarking artificial intelligence. This study evaluates GPT-5.0’s ability to interpret thyroid US images according to TI-RADS criteria and contextualizes its performance relative to expert radiologist assessment, using FNA cytology as the reference standard. Methods: This retrospective study included 100 patients (mean age 49.8 ± 12.6 years; 72 women) with cytology-confirmed diagnoses: Bethesda II (benign) or Bethesda V–VI (malignant). Each nodule had longitudinal and transverse US images acquired with high-frequency linear probes. A board-certified radiologist (>10 years’ experience) and GPT-5.0 independently assessed TI-RADS features (composition, echogenicity, shape, margin, echogenic foci) and assigned final categories. Agreement was analyzed using Cohen’s κ, and diagnostic performance was calculated using TR4–TR5 as positive for malignancy. Results: Agreement was substantial for composition (κ = 0.62), shape (κ = 0.70), and margin (κ = 0.68); moderate for echogenicity (κ = 0.48); and poor for echogenic foci (κ = 0.12). GPT-5.0 demonstrated a systematic, risk-averse tendency to up-classify nodules, leading to increased TR4–TR5 assignments. Overall, the TI-RADS agreement was 58% (κ = 0.31). The radiologist showed superior diagnostic performance (sensitivity 89%, specificity 85%) compared with GPT-5.0 (sensitivity 67%, specificity 49%), largely driven by false-positive TR4 classifications among benign nodules. Conclusions: GPT-5.0 recognizes several high-level TI-RADS features but struggles with microcalcifications and tends to overestimate malignancy risk within a risk-stratification framework, limiting its standalone clinical use. Ultrasound-specific training and domain adaptation may enable meaningful adjunctive roles in thyroid nodule assessment. Full article

Understanding how primary structural features and secondary material properties adapt to functional loads is essential to determining their effect on changes in joint biomechanics over time. The objective of this study was to map and correlate spatiotemporal changes in primary structural features, secondary material properties, and dentoalveolar joint (DAJ) stiffness with age in rats subjected to prolonged chewing of soft foods versus hard foods. To probe how loading history shapes the balance between the primary and secondary features, four-week-old rats were fed either a hard-food (HF, N = 25) or soft-food (SF, N = 25) diet for 4, 12, 16, and 20 weeks, and functional imaging of intact mandibular DAJs was performed at 8, 12, 16, 20, and 24 weeks. Across this time course, the primary structural determinants of joint function (periodontal ligament (PDL) space, contact area, and alveolar bone socket morphology) and secondary material and microstructural determinants (tissue-level stiffness encoded by bone and cementum volume fractions, pore architecture, and bone microarchitecture) were quantified. As the joints matured, bone and cementum volume fractions increased in both the HF and SF groups but along significantly different trajectories, and these changes correlated with a pronounced decrease in PDL-space from 12 to 16 weeks in both diets. With further aging, older HF rats maintained significantly wider PDL-spaces than SF rats. These evolving physical features were accompanied by an age-dependent significant increase in the contact ratio in the SF group. The DAJ stiffness was significantly greater in SF than HF animals at younger ages, indicating that food hardness-dependent remodeling alters the relative contribution of structural versus material factors to joint function across the life course. At the tissue level, volumetric strains, representing overall volume changes, and von Mises bone strains, representing shape changes, increased with age in HF and SF joints, with volumetric strain rising rapidly from 16 to 20 weeks and von Mises strain increasing sharply from 12 to 16 weeks. Bone in SF animals exhibited higher and more variable strain values than age-matched HF bone, and changes in joint space, degrees of freedom, contact area, and bone strain correlated with joint biomechanics, demonstrating that multiscale functional biomechanics, including bone strain in intact DAJs, are colocalized with anatomy-specific physical effectors. Together, these spatiotemporal shifts in primary (structure/form), and secondary features (material properties and microarchitecture) define divergent mechanobiological pathways for the DAJ and suggest that altered loading histories can bias joints toward early maladaptation and potential degeneration. Full article

T. remus is an important egg parasitoid of S. frugiperda, serving as a significant role in its biological control. This study systematically examined the host discrimination behavior of T. remus. The parasitic process comprises several distinct behavioral stages: host searching, antennal tapping and examination, ovipositor probing, “8”-shaped marking, and grooming. Following successful oviposition, females perform a characteristic “8”-shaped marking on the host egg surface with their ovipositor, which deters conspecific females from parasitizing the same host. T. remus exhibited a pronounced ability to discriminate parasitized hosts, utilizing both antennae and ovipositor to avoid superparasitism. As host density increased, the searching time of T. remus decreased while the parasitism rate increased, eventually stabilizing. Parasitic discrimination was significantly influenced by oviposition experience: experienced females effectively recognized marked host eggs across a temperature range of 16 to 36 °C and time intervals of 0 to 12 h post oviposition. In contrast, naive females exhibited discrimination ability only at lower temperature (16 °C) and immediately following oviposition (0 h). These findings deepen the understanding of the behavioral ecology of T. remus and provide a crucial theoretical basis for its efficient application in the biological control of S. frugiperda. Full article

Eyeblink conditioning (EBC), a form of Pavlovian learning that relies on cerebellar circuits, offers a translationally relevant assay of adaptive learning and cerebellar integrity. In delay EBC, a conditioned stimulus (CS), such as a tone, overlaps with and co-terminates with the unconditioned stimulus (US), typically a brief air puff to the cornea. Trace EBC introduces a stimulus-free interval between CS offset and US onset, engaging additional brain structures such as the hippocampus. Acquisition of conditioned responses (CRs), their timing, and resistance to extinction have all been linked to cerebellar function. While EBC is a well-established paradigm in the experimental analysis of behavior and neuroscience, human studies applying it to ADHD populations remain limited and show inconsistent findings. One potential explanation for this variability lies in procedural differences across studies, particularly in the temporal structure of conditioning trials. A key parameter in Pavlovian learning is the ratio of the inter-US interval (C; time between USs) to the CS–US interval (T; time between CS onset and US onset). Known as the C/T ratio, this value indexes the informational value of the CS in predicting the US and has been shown to influence acquisition speed and response strength. Despite its theoretical importance, the C/T ratio is rarely reported or standardized in human EBC studies involving ADHD. The present review aims to characterize procedural features—especially C/T ratios—used in EBC research with ADHD populations or models, with a focus on how such parameters may shape performance and interpretability in studies probing cerebellar function. Full article

Microfluidic paper-based analytical devices (µPADs) convert ordinary cellulose into an active analytical platform where capillary gradients shape transport, surface chemistry guides recognition, and embedded electrodes or optical probes translate biochemical events into readable signals. Progress in fabrication—from wax and stencil barriers to laser-defined grooves, inkjet-printed conductive lattices, and 3D-structured multilayers—has expanded reaction capacity while preserving portability. Detection strategies span colorimetric fields that respond within porous fibers, fluorescence and ratiometric architectures tuned for low abundance biomarkers, and electrochemical interfaces resilient to turbidity, salinity, and biological noise. Applications now include diagnosing human body fluids, checking food safety, monitoring the environment, and testing for pesticides and illegal drugs, often in places with limited resources. Researchers are now using learning algorithms to read minute gradients or currents imperceptible to the human eye, effectively enhancing and assisting the measurement process. This perspective article focuses on the newest advancements in the design, fabrication, material selection, testing methods, and applications of µPADs, and it explains how they work, where they can be used, and what their future might hold. Full article

Ceramides are central to stratum corneum barrier organization and hydration. Beyond topical replenishment, ceramide-stimulating strategies increasingly aim to enhance endogenous ceramide biosynthesis, processing, and homeostatic remodeling in coordination with keratinocyte differentiation. In this review, we summarize the three major metabolic routes that shape epidermal ceramide output—de novo synthesis, salvage, and sphingomyelin hydrolysis—and organize representative bioactive ingredients by their primary molecular targets rather than by origin. Specifically, we map ingredients to tractable regulatory nodes, including transcriptional “liposensors” (PPAR/LXR), the induction of biosynthetic/elongation and processing enzymes (e.g., SPT, CerS3, ELOVL4), the provision of structural substrates and precursors (e.g., linoleate-rich lipids and glycosylceramides), salvage-pathway sphingoid bases that can reshape ceramide subclass output, and metabolic sensing/stress-response pathways centered on AMPK–mTOR–SIRT1/autophagy. Across these mechanisms, agents spanning botanical and fermented extracts, vitamins, sphingoid intermediates, lipid precursors, and pathway modulators (including autophagy-focused probes) have been reported to increase ceramide abundance and, in some contexts, favor barrier-relevant ultra-long-chain species and ω-O-acylceramides that support lamellar organization and the corneocyte lipid envelope. Translational and clinical studies in dry, sensitive, and aged skin generally associate such interventions with improved barrier function and reduced dryness. Aligning ingredient selection with defined biosynthetic and processing checkpoints—and verifying outcomes with lipidomics alongside clinical endpoints—may accelerate the development of evidence-based, ceramide-stimulating cosmetics. Full article

Biosynthetic gas vesicles (GVs), as novel nanoscale ultrasound contrast agents, exhibit unique potential in biomedical ultrasound imaging. For example, they are expected to have better tissue penetration through the tumor vasculature for detecting tumor cells by the design of GV-based acoustic probes. Of all these GVs, GVs from Halobacterium sp. NRC-1 possess the largest size (over 200 nm) and are nearly spherical in shape, endowing them with stronger acoustic signals and better tumor penetration. However, their genetic manipulation is relatively difficult due to the requirement of a high-salt cytoplasmic environment for their expression and assembly, limiting the application of biosynthetic technology for modulating their structural features in heterologous host cells. In this study, we cloned the gene cluster encoding GVs from Halobacterium sp. NRC-1 and transformed it into Haloferax volcanii, an archaeal species naturally incapable of producing GVs. The genetically engineered Haloferax volcanii successfully synthesized functional GVs (GV_vol) with a similar size and shape to naturally synthesized GVs from Halobacterium sp. NRC-1 (GV_halo). The ultrasound imaging properties of GV_vol heterologously synthesized in Haloferax volcanii were compared with naturally synthesized GV_halo in vitro and in vivo, showing that GV_vol could achieve a mean signal intensity of 113.6 ± 0.9 a.u. in vitro and a peak intensity of 121.5 ± 0.8 a.u. in vivo in the kidney, compared with 115.7 ± 0.5 a.u. and 119.0 ± 0.5 a.u. for GV_halo, respectively. These findings confirm the functional integrity of heterologously synthesized GV_vol and its potential for biomedical applications. Our study provides a solid experimental foundation for genetically tailoring Halobacterium GV properties to optimize biomedical imaging performance. Full article

In this research, we assess the feasibility of employing hybrid friction stir channeling (HFSC) to produce composite panels that combined an 8 mm thick AA6082-T6 aluminum alloy and 5 mm thick glass-fiber-reinforced Noryl GFN2. HFSC is an innovative solid-state technology that combines both friction stir joining and channeling characteristics, which enable the generation of integral internal channels while joining different components. A parametric study was outlined to explore the effects of the travel speed, probe length, and tool plunging on the resulting composite panels. The resulting composite panels were subsequently subjected to a comprehensive analysis encompassing exterior ceiling quality, internal channel, and joining interface morphology. Depending on the processing parameters, the geometry of the channels was found to be quasi-rectangular or quasi-trapezoidal, with significant variability on cross-sectional area, resulting in hydraulic diameters ranging from 1.2 to 2.9 mm. The joining interface was characterized by a concavity of aluminum that was extruded downwards into the polymeric molten pool, which was clinched after polymeric re-solidification. The experimental results prove the ability to join metals and polymers while creating an integral channel in a single process step using HFSC. Despite the positive effect of irregular shaped channels on heat exchange, the numerical models evidenced a detrimental effect of 14.3 and 16.3% on ultimate tensile and flexural loads, respectively. This way, this fabrication technology evidenced promising characteristics that are suitable for manufacturing thermal management systems such as conformal cooling for plastic injection molding or battery trays for EVs. Full article