Search Results (731)

Solid lipid nanoparticles (SLNs) are submicron colloidal systems widely investigated as drug carriers; however, their intrinsic biodistribution properties are also critical when SLNs are considered for diagnostic imaging. In the present proof-of-concept study, drug-free SLNs were evaluated exclusively as a radiolabeled imaging agent rather than as a drug delivery system. SLNs were radiolabeled with Technetium-99m (^99mTc), and their in vivo biodistribution was investigated using gamma camera imaging, ex vivo organ counting, and confocal microscopy. SLNs were prepared by a microemulsion–low-temperature solidification method and characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Radiolabeling efficiency was determined by instant thin-layer chromatography (ITLC) and exceeded 95%. Following intravenous administration in a rabbit model, dynamic scintigraphic imaging demonstrated predominant uptake in the liver and spleen. These findings were quantitatively confirmed by ex vivo biodistribution analysis at 4 h post-injection and qualitatively supported by confocal microscopy of liver and spleen tissues. The results indicate that ^99mTc-labeled SLNs behave as RES-targeting radiocolloids and may serve as potential agents for liver–spleen scintigraphy. Full article

Subjective, imprecise evaluation of lower extremity function hinders the effective treatment of gait impairments in Parkinson’s disease (PD). Markerless motion capture (MMC) offers opportunities for integrating objective biomechanical outcomes into clinical practice. However, validation of MMC biomechanical outcomes is necessary for clinical adoption of MMC technologies. This project evaluated the criterion validity of a custom MMC algorithm (CART-MMC) against gold-standard 3D motion capture (Traditional-MC) and its known-groups validity in differentiating PD from healthy controls (HC). Sixty-two individuals with PD and 29 HCs completed a stepping in place paradigm. The trials were recorded by an augmented reality headset with embedded RGB and depth cameras. The CART-MMC algorithm was used to reconstruct a 3D pose model and compute biomechanical measures of lower extremity performance. CART-MMC outcomes were statistically equivalent, within 5% of Traditional-MC, for measures of step count, cadence, duration, height, height asymmetry, and normalized path length. CART-MMC captured significant between-group differences in step height, height variability, height asymmetry, duration variability, and normalized path length. In conclusion, CART-MMC provides valid biomechanical outcomes that characterize important domains of PD lower extremity function. Validated biomechanical evaluation tools present opportunities for tracking subtle changes in disease progression, informing targeted therapy, and monitoring treatment efficacy. Full article

Underwater electrical explosions of single metallic wires driven by microsecond current pulses are investigated and compared with previously reported sub-microsecond experiments. Current and voltage waveforms, streak camera shadow imaging, and one-dimensional hydrodynamic simulations are employed to characterize how the energy density, energy density deposition rate, and the generated shock waves in water depend on the wire parameters. It was found that, similar to the sub-microsecond timescale, the solid–liquid phase transition occurs later than thermodynamic calculations predicted, while the liquid–vapor phase transition happens sooner than expected, leading to a two-phase coexistence. Additionally, most materials show a notable resistance peak (Ti, Fe, Ni, Zn, Ag, Sn, Ta, Au) compared to a quasi-plateau for Cu and Mo or a continuous increase for Al and Pt. Moreover, the specific action integral values are significantly smaller than those observed in wire explosion experiments in vacuum. Finally, the plasma formed at peak resistive voltage is non-ideal but exhibits lower electron density, ionization degree, and temperature compared to the sub-microsecond case. Full article

Analyzing three-dimensional (3D) phenotypic parameters of maize seedlings is of significant importance for maize cultivation and selection. However, existing methods often struggle to balance cost, efficiency, and accuracy, particularly when capturing the complex morphology of seedlings characterized by slender stems. To address these issues, this study proposes a novel end-to-end automated framework for extracting phenotypes using only consumer-grade RGB cameras. The pipeline initiates with Instant-NGP to rapidly reconstruct dense point clouds, establishing the 3D data foundation for phenotypic extraction. Subsequently, we formulate a directed topological graph-based mechanism. By mathematically defining bifurcation constraints via vector analysis, this mechanism guides a depth-first traversal strategy to explicitly disentangle stem and leaf skeletons. Building upon these decoupled skeletons, organ-level point cloud segmentation is achieved through constraint-based expansion, followed by density-based spatial clustering (DBSCAN) to detect individual leaves. Algorithms combining point cloud geometry with 3D Euclidean distance are also implemented to calculate key phenotypes including plant height and stem width. Finally, single-leaf skeleton fitting is used to estimate leaf length, and principal component analysis (PCA) is adopted to determine the stem–leaf angle, realizing the comprehensive automatic extraction of maize seedling phenotypes. Experiments show that the proposed method achieves high accuracy in extracting key phenotypic parameters. The mean relative errors for plant height, stem width, leaf length, stem-leaf angle, and leaf area are 0.76%, 2.93%, 1.26%, 2.13%, and 3.33%, respectively. Compared with existing methods as far as we know, the proposed method significantly improves extraction efficiency by reducing the processing time per plant to within 5 min while maintaining such high accuracy. Full article

Accurate identification and characterization of subcutaneous tumors are essential for improving breast tumor detection and treatment. This study introduces an innovative Tactile-Sensation Imaging System (TSIS) designed, implemented, and tested to detect and characterize subcutaneous inclusions simulating breast tumors. The system employs a multilayered polydimethylsiloxane (PDMS) optical waveguide that mimics the tactile structure of the human fingertip. By introducing light at a critical angle, the design enables continuous total internal reflection (TIR) within the flexible, transparent waveguide. When external pressure is applied, deformation of the contact area causes light scattering, which is recorded using a high-definition camera and processed as tactile images. Analysis of these images allows estimation of inclusion characteristics such as size, depth, and mechanical properties, including Young’s modulus. Analytical modeling and numerical simulations validated the optical performance of the waveguide, while experimental evaluations using realistic tissue phantoms confirmed the system’s ability to accurately detect and quantify embedded inclusions. The results demonstrated reliable estimations of inclusion dimensions, depths, and stiffness, verifying the system’s sensitivity and precision. The TSIS offers a noninvasive, portable, and cost-efficient solution for quantitative breast tumor assessment, bridging the gap between manual palpation and advanced imaging, with future enhancements aimed at improving resolution and diagnostic accuracy. Full article

Background/Objectives: Lymphedema is characterized by edema; in severe cases, skin changes and ulceration significantly impair patients’ quality of life. Although several experimental rodent models for lymphedema have been established, a reproducible and practical model remains essential for evaluating new therapeutic and imaging agents. This study aimed to establish a lymphedema animal model and to evaluate the efficacy of a newly synthesized dual-mode imaging reagent as a potential alternative to indocyanine green (ICG). Methods: Eleven Sprague-Dawley rats were classified into two groups. Full-thickness skin excision was performed on the tails of nine rats to induce lymphedema; two rats served as controls. Five rats received ICG injections for 1 week postoperatively, while the remaining six rats were administered tail injections of chemically synthesized indocyanine green-methylene blue (ICG-MB) reagent. Lymphatic flow was photographed using a SPY camera. After euthanasia, tail segments were analyzed by microcomputed tomography (micro-CT) to measure volume and by hematoxylin–eosin staining for histological evaluation. Results: On postoperative day 7, lymphatic flow was confirmed in the ICG-MB group using the SPY Elite^® fluorescence imaging system. On micro-CT scans, the preoperative rat tail volume was 3992.72 ± 144.80 mm³. Rat tail volume was 5216.71 ± 1131.88 and 4614.76 ± 468.29 mm³, respectively, at 1 and 2 weeks after lymphedema was induced. Histology revealed lymphocyte infiltration, inflammatory reaction, and thickened subcutaneous adipose tissue, with no significant difference between groups. Conclusions: The rat tail lymphedema model proved valuable for studying lymphedema pathology and diagnostic agents. The ICG-MB reagents demonstrate stable performance and favorable biocompatibility. Full article

Endoscopes are widely used in medicine, making objective evaluation of imaging performance essential for device development and quality assurance. Image resolution is commonly characterized by the modulation transfer function (MTF); however, its interpretation depends critically on how spatial frequency is defined and reported. Because spatial frequency is directly tied to sampling, it can be expressed in different units across the imaging chain, including the object plane, image sensor plane, and digital image domain. Inconsistent conversion between these spaces and domains can mislead comparisons and even alter the apparent ranking of regions of interest (ROIs) or imaging systems. This work presents a systematic analysis of spatial-frequency relationships along the endoscopic imaging chain and provides a practical conversion and interpretation workflow for MTF analysis. The framework accounts for sensor sampling, in-camera processing, resampling or scaling, and geometric distortion. Because geometric distortion introduces position-dependent sampling across the field of view, ROI-specific local-magnification measurements are incorporated to convert measured MTFs to a consistent object space spatial-frequency axis. Two case studies illustrate the implications. First, an off-axis ROI may appear to outperform the image center when MTF is expressed in digital image domain cycles per pixel, but this conclusion reverses after conversion to object space cycles per millimeter using local magnification. Second, resampled image outputs can yield inflated MTF curves unless scaling differences between formats are explicitly incorporated into the spatial-frequency axis. Overall, the proposed conversion and reporting workflow enables consistent and physically meaningful MTF comparison across devices, ROIs, and acquisition configurations when geometric distortion, sampling, or resampling differs, clarifying how optics, sensor characteristics, and image processing jointly determine reported MTF results. Full article

FLASH radiotherapy requires real-time, non-invasive beam monitoring systems capable of operating under ultra-high dose rate (UHDR) conditions without perturbing the therapeutic beam. In this work, we characterized the extraction system of Supersonic Gas Curtain-based Ionization Profile Monitor (SGC-IPM) for its capabilities as a transverse beam profile and position monitor for FLASH protons. The monitor utilizes a tilted gas curtain intersected by the incident beam, leading to the generation of ions that are extracted through a tailored electrostatic field, and detected using a two stage microchannel plate (MCP) coupled to a phosphor screen and CMOS camera. CST Studio Suite was employed to conduct electrostatic and particle tracking simulations evaluating the ability of the extraction system to measure both beam profile and position. The ion interface, at the interaction region of proton beam and gas curtain, was modeled with realistic proton beam parameters and uniform gas curtain density distributions. The ion trajectory was tracked to evaluate the performance across multiple beam sizes. The simulations suggest that the extraction system can reconstruct transverse beam profiles for different proton beam sizes. Simulations also supported the system’s capability as a beam position monitor within the boundary defined by the beam size, the dimensions of the extraction system, and the height of the gas curtain. Some simulation results were benchmarked against experimental data of 28 MeV proton beam with 70 nA average beam current. This study will further help to optimize the design of the extraction system to facilitate the integration of SGC-IPM in medical accelerators. Full article

Compound meta-optics, characterized by the unprecedented complex optical architectures containing single or multiple meta-optics elements, has emerged as a powerful paradigm for overcoming the physical limitations of single-layer metasurfaces. This review systematically examines the recent progress in this burgeoning field, primarily focusing on the development of high-performance optical systems for imaging, display, sensing, and computing. We first focus on the design of compound metalens architectures that integrate metalenses with additional elements such as iris, refractive optics, or other meta-optics elements. These configurations effectively succeed in providing multiple high-quality image quality metrics simultaneously by correcting monochromatic and chromatic aberrations, expanding the field of view, enhancing overall efficiency, and so on. Thus, the compound approach enables practical applications in next-generation cameras and sensors. Furthermore, we explore the advancement of cascaded metasurfaces in the realm of wave-optics, specifically for advanced meta-holography and optical computing. These multi-layered systems facilitate complex wavefront engineering, leading to significant increases in information capacity and functionality for security and analog optical computing applications. By providing a comprehensive overview of fundamental principles, design strategies, and emerging applications, this review aims to offer a clear perspective on the pivotal role of compound meta-optics in devising and optimizing compact, multifunctional optical systems to optics engineers with a variety of professional knowledge backgrounds and techniques. Full article

Slag entrainment within the mold is a significant cause of surface defects in continuously cast slabs. As a key component for controlling molten steel flow, the structure of the submerged entry nozzle directly influences the flow field characteristics and slag entrainment behavior within the mold. This paper employs a 1:4-scale water–oil physical model combined with numerical simulation to investigate the effects of elliptical and circular submerged entry nozzles on slag entrainment behavior in a wide slab mold under different casting speeds and immersion depths. High-speed cameras were used to visualize meniscus fluctuations and oil droplet entrainment processes. An alternating control variable method was employed to quantitatively delineate a slag-free “safe zone” and a “slag entrainment zone” where oil droplets fall, determining the critical casting speed and critical immersion depth under different operating conditions. The results show that, given the nozzle immersion depth and slag viscosity, the maximum permissible casting speed range without slag entrainment can be obtained, providing a reference for industrial production parameter control. The root mean square (RMS) of surface fluctuations was introduced to characterize the activity of the meniscus flow. It was found that the RMS value decreases with increasing nozzle immersion depth and increases with increasing casting speed, showing a good correlation with the frequency of slag entrainment. Numerical simulation results show that compared with elliptical nozzles, circular nozzles form a more symmetrical flow field structure in the upper recirculation zone, with a left–right vortex center deviation of less than 5%, resulting in higher flow stability near the meniscus and thus reducing the risk of slag entrainment. Full article

Background and Objectives: Keratoconus is a bilateral but often asymmetric ectatic corneal disease characterized by progressive thinning, increased curvature, and conical shape of the cornea. Previous studies have reported that the use of swimming goggles in patients with keratoconus can lead to increased intraocular pressure (IOP) and a transient reduction in anterior chamber volume (ACV), potentially affecting anterior segment morphology. This study aimed to evaluate the short-term effects of periorbital pressure induced by swimming goggles on corneal parameters in keratoconic eyes. Materials and Methods: A total of 44 eyes of 44 patients (mean age: 26.1 ± 5.1 years) diagnosed with keratoconus Stage 1–4 according to the Amsler–Krumeich classification were included. Measurements were taken using a Pentacam^® Scheimpflug camera before swimming goggle application and immediately after 20 min of wear. The parameters assessed included keratometry values (K1, K2, Km, Kmax), central and thinnest corneal thickness, corneal volume within the 10 mm zone (CV10), ACV, anterior chamber depth (ACD), iridocorneal angle (ICA), and pupil diameter (PD). Results: No statistically significant changes were observed in keratometric values, central and thinnest corneal thickness, ACV, ACD, ICA, PD, or IOP (all p > 0.05). CV10 showed a small reduction following goggle wear (Δ = −0.18 mm³, corresponding to a 0.3% decrease), which was statistically significant in the unadjusted analysis (p = 0.008) but did not remain significant after correction for multiple comparisons (p for false discovery rate [FDR] = 0.10). Conclusions: Short-term swimming goggle use may induce subtle reductions in CV10 in keratoconic eyes, suggesting a potential biomechanical sensitivity to transient periocular pressure. Although the observed change in CV10 did not retain statistical significance after multiple-comparison correction, it may reflect an early physiological response in structurally compromised corneas. CV measurements could serve as exploratory indicators of mechanical responsiveness in keratoconus, warranting further investigation in larger controlled studies. Full article

To address the bottlenecks of traditional jaw crusher liner wear detection—high safety risks, insufficient precision, and limited full-range analysis—this paper proposes a non-contact, high-precision wear analysis method based on binocular vision and deep learning. At its core is the integration of the state-of-the-art FoundationStereo zero-shot stereo matching algorithm, following scenario-specific adaptations, into the 3D reconstruction of industrial liners for wear analysis. A novel wear quantification methodology and corresponding indicator system are also proposed. After calibrating the ZED2 binocular camera and fine-tuning the algorithm, FoundationStereo achieves an Endpoint Error (EPE) of 0.09, significantly outperforming traditional algorithms. To meet on-site efficiency requirements, a “single-view rapid acquisition + CUDA engineering acceleration” strategy is implemented, reducing point cloud generation latency from 165 ms to 120 ms by rewriting kernel functions and optimizing memory access patterns. Geometric accuracy verification shows a Mean Absolute Error (MAE) ≤ 0.128 mm, fully meeting industrial measurement standards. A complete process of “3D reconstruction–model registration–quantitative analysis” is constructed, utilizing three core indicators (maximum wear depth, average wear depth, and wear area ratio) to characterize liner wear. Statistical results—such as an average maximum wear depth of 55.05 mm—are highly consistent with manual inspection data, providing a safe, efficient, and precise digital solution for the predictive maintenance and intelligent operation and maintenance (O&M) of liners. Full article

This paper presents the procedures employed for experimental functional and performance characterization of a 2 × 2 pixel prototype detection system tailored specifically for the X and Gamma-ray Imaging Spectrometer (XGIS) instrument onboard the THESEUS mission. The XGIS system comprises of two coded masked wide field cameras integrated with monolithic SDDs (Silicon Drift Detectors) and CsI:Tl (Thallium doped-Cesium Iodide) scintillators, contributing to its broad X and $\gamma$-ray detection range. Given the space instrumentation complexity, thorough requirement qualification and testing procedures are essential. This work focuses on working principle, the testing setup utilized, and observed performance for the small scale four-pixel XGIS prototype. Furthermore, the alignment of light output performance of the four-pixel SDD and scintillator prototype detection system with the XGIS instrument requirements is emphasized. Full article

Using additive manufacturing for the design of inserts in injection moulding (IM) offers advantages in product development and customization. However, challenges related to operating temperature and mechanical resistance remain. This article presents a systematic screening methodology to evaluate the suitability of materials for specific applications. Ten commercial Material Extrusion (MEX) filaments were selected to produce test samples. Moldex3D simulation software was employed to model the IM process using two thermoplastics and to determine the temperature and pressure conditions that the printed inserts must withstand. Simulation results were critically interpreted and cross-referenced with the experimental material characterisations to evaluate material suitability. Nine of the ten MEX materials were suitable for IM with LDPE, and five with PP. Dimensional assessments revealed that six insert solutions required further post-processing for assembly, while three did not. All of the selected materials successfully survived 10 injection cycles without encountering any significant issues. The simulation results were validated by comparing temperature data from a thermal imaging camera during IM, revealing only minor deviations. The study concludes that combining targeted material characterization with CAE simulation provides an effective and low-cost strategy for selecting MEX filaments for injection moulding inserts, supporting rapid tooling applications in niche production. Full article

This study characterizes the chemical defense system of the invasive longhorn beetle Aromia bungii, a destructive pest of Prunus trees, addressing the limited understanding of chemical defensive mechanisms in Cerambycidae. High-speed cameras, environmental scanning electron microscopy (ESEM), dissection, and micro-CT imaging were used to investigate defensive behavior, and the structure of the defense system, in this beetle. Both sexes of A. bungii possess a pair of triangular, sac-like defensive glands symmetrically located in the metathorax, attached to the metasternum. Upon mechanical stimulation, white liquid defensive substances are rapidly ejected through a pair of slit-shaped openings (~200 µm) at the metasternum corners, without gland eversion, reaching over 50 cm. The average weight of substances ejected in first sprays was 7.95 ± 0.79 mg for females and 8.62 ± 2.13 mg for males (mean ± se), with no significant difference between sexes. However, the weight in second sprays after 10 days was significantly lower, at 2.93 ± 0.54 mg for females and 2.22 ± 0.40 mg for males (mean ± se), suggesting that the beetles cannot re-synthesize the substances soon after spray. The weight of ejected substances had no correlation with beetle body weight. Our findings represent the first detailed morphological and functional description of a chemical defense system in Cerambycidae, revealing a specialized metasternal gland and spray mechanism. The substantial but likely non-renewable defensive substances reflect an adaptive trade-off in energy allocation between reproduction and defense in this species that exhibits high fecundity but a short lifespan at the adult stage. Full article