Search Results (703)

Urbanization generates large quantities of arsenic-contaminated excavated soils that pose environmental risks due to arsenic volatilization during high-temperature sintering processes. While these soils have potential for recycling into construction materials, their reuse is hindered by arsenic release. This study demonstrated calcium hydroxide (Ca(OH)₂) as a highly effective additive for suppressing arsenic volatilization during soil sintering, while simultaneously improving material properties. Through comprehensive characterization using inductively coupled plasma-mass spectrometry (ICP-MS), scanning electron microscopy (SEM) and X-ray microtomography (μCT), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), results demonstrated that Ca(OH)₂ addition (0.5–2 wt.%) reduces arsenic volatilization by 57% through formation of thermally stable calcium arsenate (Ca₃(AsO₄)₂). Ca(OH)₂ acted via two mechanisms: (a) chemical immobilization through Ca-As-O compound formation, (b) physical encapsulation in a calcium-aluminosilicate matrix during liquid-phase sintering, and (c) pH buffering that maintains arsenic in less volatile forms. Optimal performance was achieved at 0.5% Ca(OH)₂, yielding 9.14 MPa compressive strength (29% increase) with minimal arsenic leaching (<110 ppb). Microstructural analysis showed Ca(OH)₂ promoted densification while higher doses increased porosity. This work provides a practical solution for safe reuse of arsenic-contaminated soils, addressing both environmental concerns and material performance requirements for construction applications. Full article

Background/Objective: The high-shear granulator is considered an effective piece of equipment for layering pelletization because it enhances drug amorphization and improves drug dissolution. This study aimed to apply a high-shear granulator to prepare layered pellets containing a combination of hydrochlorothiazide and amlodipine besylate with improved physicochemical properties. Methods: Different molar ratios (2:1, 1:1, and 1:2) of the hydrochlorothiazide and amlodipine besylate mixture were deposited on the surface of the inert spheres of the microcrystalline cellulose (MCC) core by the mechanical effect of the high impeller speed. The resulting layered pellets were characterized using X-ray powder diffractometry (XRPD) and differential scanning calorimetry (DSC) to estimate the degree of the drug amorphization, and consequently a dissolution test was performed to determine the degree of the enhancement of the percentage of release. Additionally, micro-computed tomography (micro-CT) and a texture analyzer were used to determine the morphological characteristics and hardness of the resulting pellets, and then a stability study was performed. Results: On the basis of the micro-CT images, the MCC core was successfully loaded with a uniform layer of the drug combination at the pellet surface, which exhibited higher diameters than pure cellets. Furthermore, the drug combination in layered pellets was partially amorphized with a lower crystallinity percentage, a lower intensity, a broadening of the hydrochlorothiazide melting peak, and a higher cumulative release of both drugs with good stability, except pellets with a molar ratio of 1:2 that were recrystallized with a higher crystallinity percentage of 79.9%. Conclusions: Modifying the physical form and dissolution behavior of the hydrochlorothiazide and amlodipine besylate combination was achieved by single-step layering pelletization. Full article

The long-term stability of grout-reinforced fractured rock masses in acidic groundwater environments after tunnel fires is critical for the safe operation of underground engineering. In this study, grouting reinforcement tests were performed on fractured diorite specimens using a high-strength fast-anchoring agent (HSFAA), and their mechanical degradation and microstructural evolution mechanisms were investigated under coupled high-temperature (25–1000 °C) and acidic corrosion (pH = 2) conditions. Multi-scale characterization techniques, including uniaxial compression strength (UCS) tests, X-ray computed tomography (CT), scanning electron microscopy (SEM), three-dimensional (3D) topographic scanning, and X-ray diffraction (XRD), were employed systematically. The results indicated that the synergistic thermo-acid interaction accelerated mineral dissolution and induced structural reorganization, resulting in surface whitening of specimens and decomposition of HSFAA hydration products. Increasing the prefabricated fracture angles (0–60°) amplified stress concentration at the grout–rock interface, resulting in a reduction of up to 69.46% in the peak strength of the specimens subjected to acid corrosion at 1000 °C. Acidic corrosion suppressed brittle disintegration observed in the uncorroded specimens at lower temperature (25–600 °C) by promoting energy dissipation through non-uniform notch formation, thereby shifting the failure modes from shear-dominated to tensile-shear hybrid modes. Quantitative CT analysis revealed a 34.64% reduction in crack volume (V_ca) for 1000 °C acid-corroded specimens compared to the control specimens at 25 °C. This reduction was attributed to high-temperature-induced ductility, which transformed macroscale crack propagation into microscale coalescence. These findings provide critical insights for assessing the durability of grouting reinforcement in post-fire tunnel rehabilitation and predicting the long-term stability of underground structures in chemically aggressive environments. Full article

Background: The anatomical variability of the nasal cavity affects intranasal drug delivery, especially to the olfactory region for nose-to-brain treatments. While previous studies used average models or 2D measurements to account for inter-individual variability, 3D shape variation of the region crossed by drug particles that target the olfactory area, namely the region of interest (ROI), remains unexplored to our knowledge. Methods: A geometric morphometric analysis was performed on the ROI of 151 unilateral nasal cavities from the CT scans of 78 patients. Ten fixed landmarks and 200 sliding semi-landmarks were digitized, using Viewbox 4.0, and standardized via Generalized Procrustes Analysis. Shape variability was analyzed through Principal Component Analysis. Morphological clusters were identified using Hierarchical Clustering on Principal Components, and characterized with MANOVA, ANOVA, and Tukey tests. Results: Validation tests confirmed the method’s reliability. Three morphological clusters were identified. Variations were significant in the X and Y axes, and minimal in Z. Cluster 1 had a broader anterior cavity with shallower turbinate onset, likely improving olfactory accessibility. Cluster 3 was narrower with deeper turbinates, potentially limiting olfactory accessibility. Cluster 2 was intermediate. Notably, 31.5% of patients had at least one cavity in cluster 1. Conclusions: Three distinct morphotypes of the region of the nasal cavity that potentially influence accessibility were identified. These findings will guide future computational fluid dynamics studies for optimizing nasal drug targeting and represent a practical step toward tailoring nose-to-brain drug delivery strategies in alignment with the principles of personalized medicine. Full article

Background/Objectives: In emergency departments (EDs), choosing imaging modalities for adolescents with abdominal pain requires balancing diagnostic accuracy and minimizing radiation exposure. This retrospective study compared imaging modalities in adolescents (16–18 years) presenting with non-traumatic acute abdominal pain between the pediatric ED (PED) and adult ED (AED) in the same institution. Methods: We conducted a retrospective study in patients aged 16–18 years who presented to AED or PED in the same tertiary university-affiliated hospital due to non-traumatic acute abdominal pain between January 2019 and July 2023 (study period = 55 months). The patient freely decided on the emergency department (ED) to be admitted. Results: This study analyzed 950 patients (683 in AED and 267 in PED). Actionable and surgical emergencies were comparable between both EDs (p = 0.617 and 0.245, respectively). PED physicians used fewer CT scans (28.5% vs. 37.9%, p = 0.006) and fewer CT phases (mean, 0.49 vs. 0.76, p < 0.001). Despite more patients undergoing X-rays in PED (77.9% vs. 61.6%, p < 0.001), the number of X-ray images was lower than in AED (mean, 0.9 vs. 1.1, p < 0.001). PED performed more point-of-care US (POCUS) than AED (28.0% vs. 0.1%, p < 0.001). Both EDs had comparable safety outcomes (revisits and missed surgical emergencies). Conclusions: PED physicians utilize POCUS more frequently and employ fewer CT scans, X-ray images, and CT phases than AED physicians in adolescents presenting with non-traumatic acute abdominal pain. Despite lower radiation exposure, the PED achieved safety outcomes comparable to the AED’s, indicating that a PED-style imaging strategy may be safely applied to adolescent abdominal pain evaluation. Full article

This study presents the development and evaluation of an Augmented Reality (AR)-based training system aimed at improving patient setup accuracy in radiation therapy. Leveraging Microsoft HoloLens 2, the system provides an immersive environment for medical staff to enhance their understanding of patient setup procedures. High-resolution 3D anatomical models were reconstructed from CT scans using 3D Slicer, while Luma AI was employed to rapidly capture complete body surface models. Due to limitations in each method—such as missing extremities or back surfaces—Blender was used to merge the models, improving completeness and anatomical fidelity. The AR application was developed in Unity, employing spatial anchors and 125 × 125 mm² QR code markers to stabilize and align virtual models in real space. System accuracy testing demonstrated that QR code tracking achieved millimeter-level variation, with an expanded uncertainty of ±2.74 mm. Training trials for setup showed larger deviations in the X (left–right), Y (up-down), and Z (front-back) axes at the centimeter scale. This meant that we were able to quantify the user’s patient setup skills. While QR code positioning was relatively stable, manual placement of markers and the absence of real-time verification contributed to these errors. The system offers a radiation-free and interactive platform for training, enhancing spatial awareness and procedural skills. Future work will focus on improving tracking stability, optimizing the workflow, and integrating real-time feedback to move toward clinical applicability. Full article

Background/Objectives: Gluteal medius tendon tears (GTT) are a common cause of greater trochanteric pain and functional impairment. Accurate preoperative imaging is critical for diagnosis and surgical decision-making. This study aimed to evaluate and compare the diagnostic accuracy of four imaging modalities—X-ray, ultrasound (US), magnetic resonance imaging (MRI), and bone scan (BS)/SPECT/CT—in detecting and grading GTT, using perioperative findings as the reference standard. Methods: In this prospective study, a cohort of 45 patients (41 women, 4 men; mean age 62.9) with suspected GTT and failed conservative treatment had open surgical treatment by augmentation of the gluteus medius tendon. All patients underwent preoperative imaging with X-ray, US, MRI, and BS. Imaging results were compared with intraoperative findings. Results: MRI demonstrated the highest sensitivity (98%) and strong PPV (91.1%), correctly identifying nearly all true positives. Ultrasound showed similar sensitivity (95%) but yielded more false positives. X-ray and BS exhibited perfect specificity and PPV (100%) but poor sensitivity (21% and 38%, respectively), limiting their utility in ruling out GTT. Conclusions: MRI is the most sensitive and reliable single modality for diagnosing GTT, though false positives remain a concern in surgical decision-making. Ultrasound, while sensitive, lacks specificity and should not be used in isolation for surgical decision-making. A multimodal imaging approach, particularly combining MRI with X-ray and BS, may offer high diagnostic certainty and help prevent unnecessary surgical interventions. Full article

This review provides a comprehensive examination of porosity and permeability as key parameters governing the durability and performance of construction materials, including natural stone, mortar, concrete, and other cementitious composites. It highlights the pivotal role of pore structure in transport phenomena and degradation mechanisms, examining how the variations in pore architecture, encompassing total vs. effective porosity, pore size distribution, and pore connectivity, dictate a material’s response to environmental stressors. A comparative evaluation of advanced pore characterization techniques is presented, including helium pycnometry, mercury intrusion porosimetry (MIP), nitrogen adsorption (BET/BJH), nuclear magnetic resonance (NMR) relaxometry, and imaging methods such as optical microscopy, scanning electron microscopy (SEM), and X-ray micro-computed tomography (micro-CT). Furthermore, it assesses how these porosity and permeability characteristics influence durability-related processes like freeze–thaw cycling, chloride ingress, sulphate attack, and carbonation. Case studies are discussed in which various additives have been employed to refine the pore structure of cement-based materials, and pervious concrete is highlighted as an example where deliberately high porosity and permeability confer functional benefits (e.g., enhanced drainage). Overall, these insights underscore the importance of tailoring porosity and permeability in material design to enhance durability and sustainability in construction engineering. Full article

Background and Clinical Significance: Bladder neoplasms often present with coexisting thrombi and hematuria, appearing as complex intraluminal masses on imaging, and posing a key diagnostic challenge in distinguishing neoplastic tissue from thrombus, to prevent harmful overstaging. Case Presentation: An 82-year-old man with recurrent gross hematuria and urinary disturbances was evaluated by ultrasound, which identified a large endoluminal lesion in the anterior bladder wall. The patient subsequently underwent contrast-enhanced CT using a second-generation dual-layer spectral CT system, which utilizes a dual-layer detector to simultaneously acquire high- and low-energy X-ray data. Conventional CT images confirmed a multifocal, bulky hyperdense lesion along the bladder wall, protruding into the lumen and raising suspicion for a heterogeneous mass, though further characterization was not possible. Spectral imaging enabled the reconstruction of additional maps—such as iodine density, effective atomic number (Z-effective), and electron density—which were used to further characterize these findings. The combination of these techniques clearly demonstrated differences in iodine uptake and tissue composition within the parietal lesions, allowing for a reliable differentiation between neoplastic tissue and intraluminal thrombus. Conclusions: The integration of conventional CT imaging with spectral-derived maps generated in post-processing allowed for accurate and reliable tissue differentiation between bladder neoplasm and thrombus. Spectral imaging holds the potential to prevent tumor overstaging, thereby supporting more appropriate clinical management. The dual-layer technology enables the generation of these maps from every acquisition without altering the scan protocol, thereby having minimal impact on the daily clinical workflow. Full article

Understanding the fatigue behavior of materials is essential for designing components capable of enduring prolonged use under varying stress conditions. This study investigates the high-cycle fatigue and fatigue crack growth characteristics of X17CrNi15-2 stainless steel. Very high-cycle fatigue (VHCF) and fatigue crack growth tests were conducted on conventional fatigue and compact tension (CT) specimens fabricated from X17CrNi15-2 stainless steel. The fatigue crack growth behavior of the CT specimens was analyzed using Paris’ law. A revised version of Paris’ law was suggested based on the fatigue crack growth rate plotted against the stress intensity factor range, expanding on prior research utilizing three-point single-edge notch bend specimens. Scanning electron microscopy (SEM) was employed to examine the fracture mechanisms of both fatigue specimen types. The results indicated that the fatigue specimens failed in the VHCF regime under stress amplitudes ranging from 100 to 450 MPa. A power law correlation between stress amplitude and fatigue life was established, with material constants of 7670.3954 and −0.1663. These findings offer valuable insights into the material’s performance and are crucial for enhancing its suitability in engineering applications where high-cycle fatigue is a critical factor. Full article

Background and Clinical Significance: Mycotic aortic aneurysm is a rare but life-threatening vascular condition characterized by infection-induced dilation or pseudoaneurysm formation in the aorta. The condition carries a high risk of rupture and mortality, especially in individuals with underlying cardiovascular disease, who have undergone recent vascular procedures, or with immunocompromising comorbidities such as diabetes. Its diagnosis is challenging due to its non-specific symptoms and often requires a high index of suspicion, especially in patients presenting with persistent fever and negative initial imaging. Early recognition and intervention are critical, as delayed treatment significantly worsens outcomes. Case Presentation: A 68-year-old male with a history of coronary artery disease, recent stent placement, and hypertension presented with two days of fever, chills, rigors, and a mild nonproductive cough. The laboratory findings were only significant for leukocytosis. The initial chest X-ray and non-contrast CT scans were unremarkable. He was admitted for presumed pneumonia and started on intravenous antibiotics. Persistent fever prompted further investigation with contrast-enhanced CT, which revealed a distal-aortic-arch pseudoaneurysm and mild mediastinal stranding. Blood cultures grew methicillin-sensitive Staphylococcus aureus (MSSA). Transthoracic echocardiogram was negative for endocarditis. The patient was transferred to a tertiary center, where repeat imaging confirmed a 1.5 cm pseudoaneurysm and a 4 mm penetrating atherosclerotic ulcer. After multidisciplinary assessment, he underwent thoracic endovascular aortic repair (TEVAR) and completed four weeks of intravenous cefazolin. Follow-up imaging showed successful aneurysm repair with no complications. Conclusions: Thoracic mycotic aneurysm is a rapidly fatal entity despite intervention. High clinical suspicion is necessary given its non-specific presentation. It is diagnosed most practically using CTA. In addition to antibiotics, TEVAR is gaining traction as a feasible and a safe alternative to open surgical repair (OSR). Full article

Leopold Blaschka (1822–1895) and his son Rudolf (1857–1939) created scientifically accurate glass models of marine invertebrates that reshaped natural history education in the 19th century. Their work overcame the limitations of traditional preservation techniques, allowing for detailed and lifelike representations of soft-bodied sea creatures and botanic species. Today, their models are preserved in prestigious collections worldwide. This paper examines not only the historical and artistic significance of the Blaschka models but also presents the findings of recent material analyses, including computed tomography (CT), scanning electron microscopy combined with energy dispersive X-ray analysis (SEM-EDS), visible ultraviolet fluorescence (UVF), and Fourier-transform infrared spectroscopy (FTIR). The multi-analytical approach allowed for the characterization of the chemical composition of the glass and adhesives used, shedding light on the Blaschkas’ unique manufacturing processes and material choices. Data from this study demonstrate how the combination of a multi-analytical approach with knowledge of historical glassmaking practices can provide a solid foundation for both conservation efforts and further academic investigation into these composite objects. The study underscores the models’ value not only as artistic masterpieces but also as technological artifacts, offering insights into 19th-century scientific craftsmanship at the intersection of art and biology. Furthermore, the study presents a conservation intervention based on scientific evidence and a skilfully tailored solution, chosen piece-by-piece, part-by-part of the intricate glass models. Full article

To elucidate the multi-performance evolution mechanisms of basalt fiber-reinforced lightweight expanded polystyrene geopolymer concrete (LEGC), a two-tiered investigation was conducted. In the first part, a series of LEGC mixtures with varying volume fractions of EPS (10–40%) and basalt fiber (BF) (0.4–0.8%) were designed. Experimental tests were carried out to evaluate density, flowability, compressive strength, flexural strength, and splitting tensile strength. Crack propagation behavior was monitored using DIC-3D speckle imaging. Additionally, X-ray CT scanning revealed the internal clustering of EPS particles, porosity distribution, and crack connectivity within LEGC specimens, while SEM analysis confirmed the bridging effect of basalt fibers and the presence of dense matrix regions. These microstructural observations verified the consistency between the synergistic effects of EPS weakening and fiber reinforcement at the microscale and the macroscopic failure behavior. The results indicated that increasing EPS content led to reduced mechanical strength, whereas the reinforcing effect of basalt fiber followed a rising-then-falling trend. Among all specimens, LEGC20BF06 exhibited the best comprehensive performance, achieving a compressive strength of 40.87 MPa and a density of 1747.6 kg/m³, thus meeting the criteria for structural lightweight concrete. In the second part, based on the experimental data, predictive models were developed for splitting tensile and flexural strengths using compressive strength as a reference, as well as a dual-factor model incorporating EPS and fiber contents. Both models were validated and demonstrated high predictive accuracy. Furthermore, a splitting tensile elasto-plastic damage constitutive model was proposed based on composite mechanics and energy dissipation theory. The model showed excellent agreement with experimental stress–strain curves, with all fitting coefficients of determination (R²) exceeding 0.95. These findings offer robust theoretical support for the performance optimization of LEGC and its application in green construction and prefabricated structural systems. Full article

This article describes research on two encapsulated phase change materials (PCMs) from the alkane group (n-hexadecane and n-octadecane) with phase transition temperatures of 18.2 °C and 28.2 °C, respectively. The main goal of the study was to determine the internal structure and basic thermal properties of both types of macrocapsules in terms of their potential applications. The internal structure of the macrocapsules was characterized using non-destructive statistical quantitative analysis performed using X-ray microtomography (micro-CT). Differential scanning calorimetry (DSC) was used to determine the phase transition temperatures, thermal cycling stability, and phase transition enthalpies of both PCMs. The macrocapsules were tested in two experiments, simulating the conditions of their potential application by exposing them to contact heat and radiant heat. Structural analysis showed that the macrocapsules differ significantly in PCM content (77% n-hexadecane and 88% n-octadecane) and porosity (19% and 10%, respectively). According to the DSC results, the macrocapsules with n-octadecane exhibited a significantly wider phase transition range and a greater ability to store latent heat indicated by its higher enthalpy by about 30 J·g⁻¹ than those with n-hexadecane. The results of experiments involving PCM exposure to contact heat and radiant heat demonstrated the potential applications of the macrocapsules in thermal packaging, building, and protective clothing. Full article

The global outbreak and prolonged presence of Coronavirus Disease 2019 (COVID-19) have resulted in a substantial accumulation of discarded masks, posing serious environmental challenges. This study proposes an eco-friendly and low-carbon strategy to repurpose discarded DMFM fibers as a key component in fiber-reinforced self-compacting recycled aggregate concrete (FRSCRAC). The mechanical and environmental performance of FRSCRAC was systematically evaluated by investigating the effects of recycled coarse aggregate (RCA) replacement ratios (0%, 50%, 100%), discarded DMFM fiber material (DMFM) contents (0%, 0.1%, 0.2%, 0.3%), and fiber lengths (2 cm, 3 cm, 4 cm) on axial compression failure mode and stress–strain behavior. The results demonstrated that DMFM fibers significantly enhanced concrete ductility and peak stress via the fiber-bridging effect. Based on fiber influence, modified stress–strain and shrinkage models for SCRAC were established. To further understand the fiber fixation mechanism, X-ray computed tomography (X-CT) and scanning electron microscopy (SEM) analyses were conducted. The findings revealed a stable random distribution of fibers and strong interfacial bonding between fibers. These improvements contributed to enhanced mechanical performance and the effective immobilization of polypropylene microfibers, preventing further microplastics release into the air. This innovative approach provides a sustainable solution for recycling and effectively immobilizing discarded DMFM fibers in concrete over long curing periods, while also enhancing its properties. Full article