Search Results (35,627)

Piezoelectric thin films have been widely used in micro-electromechanical systems (MEMSs), such as sensors, actuators, and resonant devices. Electromechanically driven fractures can severely degrade device performance and reliability. In this work, a phase-field damage model is developed for MEMS piezoelectric thin films under coupled electromechanical loading, incorporating pre-existing defects via an equivalent local fracture toughness. Microcracks and micro-voids arising from manufacturing defects are integrated into the model through an effective local fracture toughness, enabling a unified description of their roles in crack initiation and propagation. The proposed model is implemented in ABAQUS by means of a user-defined element (UEL) subroutine and solved using a staggered scheme. Numerical results show that the level of pre-existing defects, the applied electric potential, and the polarization direction all exert significant effects on fracture behavior. As the defect parameter D_c increases from 0 to 0.10, the reaction force decreases from 87.8 N to 86.3 N, indicating reduced fracture resistance due to manufacturing-induced defects. In addition, the reaction force changes from 90.3 N at −500 V to 86.3 N at +500 V, while it decreases from 102.9 N to 87.1 N as the polarization angle β increases from 0° to 90°. These results demonstrate that pre-existing defects and electromechanical loading jointly govern crack evolution in MEMS piezoelectric thin films. The present study provides a useful numerical tool for fracture analysis, reliability assessment, and structural design of MEMS piezoelectric devices containing manufacturing defects. Full article

Butyrate, a short-chain fatty acid produced by the fermentation of soluble dietary fiber by gut bacteria, also functions as a histone deacetylase inhibitor known to induce apoptosis and promote differentiation in colon tumor cells. During tumorigenesis, cancer cells undergo metabolic reprogramming to meet energetic and biosynthetic demands, increasing glycolytic metabolism and reducing oxidative metabolism—a phenomenon known as the Warburg effect. This study aimed to evaluate the impact of butyrate on the aggressiveness-related metabolic phenotype of three colon cancer cell lines (LS1034, C2BBe1, and WiDr). Butyrate’s effects were assessed through fluorine-18 fluorodeoxyglucose ([¹⁸F]FDG) uptake, flow cytometry analysis of cytoplasmic and membrane expression of glucose transporters (GLUT1, GLUT3, GLUT5, and GLUT12), lactate production, and analysis of Krebs cycle turnover and glycolysis–Krebs cycle coupling using nuclear magnetic resonance isotopomer profiling. [¹⁸F]FDG uptake decreased in C2BBe1 and WiDr cells, whereas an opposite response was observed in LS1034 cells, which also exhibited reduced GLUT5 expression. These uptake patterns were consistent with lactate production measurements, and an enhancement of oxidative metabolism was detected in C2BBe1 and WiDr cells. Although butyrate was consumed by all three cell lines, its metabolic handling appeared to differ in LS1034 cells, possibly reflecting cytotoxic stress and/or distinct metabolic regulation mechanisms. Overall, these findings indicate that butyrate exerts cell-line-dependent metabolic effects in colorectal cancer cells. In C2BBe1 and WiDr cells, butyrate exposure was broadly consistent with the attenuation of glycolytic/Warburg-associated features, whereas LS1034 cells displayed a divergent response and were interpreted separately. These data support further investigation of butyrate as a modulator of colorectal cancer cell metabolism, while highlighting the heterogeneity of metabolic responses across tumor models. Full article

Background/Objectives: Adolescent lumbar disc herniation (ALDH) is rare. Evidence on long-term surgical outcomes remains limited. The objective of this study was to evaluate mid- and long-term clinical outcomes following lumbar microdiscectomy in adolescents with lumbar disc herniation (LDH). Methods: A single-institution retrospective cohort study of patients under 19 years who underwent lumbar microdiscectomy over a ten-year period. Baseline clinical and radiological data were obtained from electronic patient records (EPR) and Magnetic Resonance Imaging (MRI). Patient-reported outcomes were collected at follow-up using the Oswestry Disability Index (ODI) as the primary outcome and Numeric Rating Scales (NRS) for back and leg pain and Global Perceived Effect (GPE) as secondary outcomes. Descriptive statistics were used to summarize results. Results: Seventeen of 27 patients (63%) participated. Mean age at surgery was 16.9 years, and mean symptom duration prior to surgery was 11.3 months. All patients underwent disc-preserving microdiscectomy. At a mean follow-up of 67.7 months, mean ODI was 9.5, mean NRS back pain was 2.8, and mean NRS leg pain was 2.3. Fourteen patients (82%) reported being completely recovered or much improved. Conclusions: Lumbar microdiscectomy in adolescents with LDH showed acceptable mid- to long-term outcomes, low disability, and low pain levels at more than five years of follow-up. Clinical and imaging findings resembled those seen in adults, though symptom duration before surgery was prolonged. Full article

Upper tract urothelial carcinoma (UTUC) is a rare and aggressive malignancy, accounting for only 5–10% of all urothelial carcinomas (UCs). Lung, bone, liver, and distant lymph nodes are common sites of metastasis, while gastrointestinal metastasis is extremely rare. We present a case of a 63-year-old female who developed a descending colon lesion 19 months after left radical nephroureterectomy for high-grade ureteral UC. The diagnosis was established by computed tomography (CT), magnetic resonance imaging (MRI), colonoscopy, and biopsy, which excluded primary colorectal malignancy. First-line therapy consisted of six 21-day cycles of gemcitabine plus cisplatin, followed by two cycles of tislelizumab maintenance immunotherapy. Restaging with contrast-enhanced CT and positron emission tomography/computed tomography (PET/CT) demonstrated disease progression. Despite switching to second-line nab-paclitaxel, the patient rapidly deteriorated from tumor cachexia and ultimately succumbed to septic shock secondary to severe pulmonary infection. This represents the first reported case of descending colon metastasis from primary ureteral UC. It highlights the colon as a potential metastatic site where biopsy is essential for definitive diagnosis. Notably, although the patient initially responded to platinum-based therapy, the subsequent rapid progression underscores the need for vigilant monitoring and timely adjustment of therapeutic strategies in managing such high-risk presentations. Full article

Silicon carbide (SiC) has emerged as a highly attractive material for microelectromechanical systems (MEMS) operating in harsh environments, owing to its outstanding mechanical, thermal, and chemical properties. This review provides a comprehensive overview of the advantages and limitations of SiC-based MEMS, with particular emphasis on the strong interdependence between material structure, mechanical properties, and epitaxial growth processes. The role of defects, residual stress, and crystal quality is discussed in relation to device performance and reliability. Special attention is devoted to cubic SiC grown on silicon substrates, highlighting how growth-induced features influence the mechanical response of micromachined structures. Furthermore, a detailed analysis of the quality factor (Q-factor) is presented for 3C-SiC (111)/Si resonators, including the development of analytical models and their validation through numerical simulations performed using COMSOL Multiphysics (Version 6.1). The necessity of incorporating anisotropic loss factors in numerical modeling is demonstrated to be essential for accurately describing the experimentally observed behavior. This review aims to provide design guidelines and modeling strategies for the optimization of SiC MEMS, supporting their further development for high-performance and extreme-environment applications, including pressure sensors, mechanical resonators and high-stress-tolerant sensors. Full article

This study introduces a switchable and tunable multimodal, multi-peak, perfect terahertz absorber, utilizing a composite structure of graphene and double concentric metal rings. From bottom to top, the absorber consists of a gold substrate, a SiO₂ dielectric layer, a patterned graphene layer, another SiO₂ dielectric layer, and double concentric metal rings on the top. The structure achieves three high-absorption resonance peaks in the far-infrared band: a relatively broad peak with 99.05% absorptance at 38.128 THz, and two extremely narrow peaks with 99.56% and 97.23% absorptance at 47.909 THz and 49.873 THz, respectively. Analysis of the absorption spectra and electric field distributions reveals that the generation mechanism of Peak I is Fabry–Pérot cavity resonance, while Peaks II and III result from the coupling between the high-order localized surface plasmons in the outer ring and the graphene surface plasmon polaritons. Benefiting from graphene’s excellent electrical tunability, the absorption peaks’ positions and intensities can be dynamically tuned by varying the Fermi level. The core innovation of this work lies in the high-level integration of multiple functionalities. By leveraging the sensitive response of Peak III to variations in the Fermi level, a four-input AND logic gate is embedded within the metamaterial absorber in this frequency band. The Fermi levels of four independent graphene regions serve as the binary inputs, while the absorption state of Peak III is defined as the logical output. Additionally, the two narrow peaks display high sensitivity to the surrounding refractive index, with sensitivities of 30.1 THz/RIU and 62.5 THz/RIU, demonstrating significant potential for sensing. This multifunctional integrated device combines tunable absorption, a logic gate, and sensing capabilities, making it promising for terahertz communication systems, intelligent sensing networks, and reconfigurable platforms. Full article

Polyaniline-cadmium sulfide-gold (PANI-CdS-Au) nanocomposites were synthesized with varying Au loadings (0.023, 0.046, 0.092 wt%) to enhance antibacterial performance. Structural (FTIR, XRD) and morphological (FESEM) analyses confirmed successful formation, with nearly homogeneous nanoparticle distribution (27–53 nm) and slight XRD peak shifts indicating interfacial interactions between PANI, CdS, and Au. UV–Vis spectra revealed gold surface plasmon resonance and polaronic transitions consistent with PANI emeraldine base. XRD results showed the expected wurtzite CdS and fcc Au phases. Agar well diffusion tests against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) demonstrated that the 0.092 wt% of Au composite produced the largest inhibition zones at 100 µg mL⁻¹ (E. coli: 36 mm; S. aureus: 24 mm), with the same trend at 25 µg mL⁻¹. The results indicate that PANI–CdS/Au nanocomposites are promising antibacterial materials; however, the presence of CdS necessitates additional cytotoxicity assays to confirm their suitability for medical applications. Full article

Seismic-induced torsional response remains a significant barrier to achieving resilient and sustainable building foundations, as traditional passive isolation systems often fail to regulate rotational motion effectively. This study examines an adaptive gyroscopic feedback-based foundation control system designed to provide automated torsional seismic mitigation. The proposed system integrates real-time angular velocity sensing using MEMS gyroscopes, Kalman filter state estimation, and an adaptive Linear Quadratic Regulator to modulate damping in response to changing ground motion. A single-degree-of-freedom torsional foundation model was developed and evaluated in GNU Octave 8.4.0/MATLAB R2024a Simulink using the recorded El Centro 1940 NS earthquake input. The adaptive controller achieved notable improvements, reducing total vibration energy by 69%, peak angular displacement by 47.6%, and RMS angular velocity by 39.5% relative to the uncontrolled case, while keeping control energy below 19% of the seismic input. These results demonstrate that gyroscopic feedback enhances damping, limits torsional resonance, and stabilises foundation behaviour under actual earthquake excitation. The system’s low energy requirement, compatibility with embedded hardware, and automated response characteristics underscore its potential for integration into sustainable and intelligent foundation designs. While results are demonstrated using the El Centro 1940 record as a benchmark, broader generalisation will be established through multi-record suites and uncertainty quantification in future work. The study highlights a feasible pathway for advancing automated seismic protection in buildings through active, sensor-driven torsional control. Full article

To address the low accuracy of faulty feeder detection methods based on single-fault characteristics, we propose a faulty feeder detection method for resonant grounding systems that fuses multiple transient characteristics. First, we analyze the transient zero-sequence current fault characteristics of both faulty and healthy feeders during single-phase-to-ground (SPG) faults. Then, the transient zero-sequence current of each feeder is decomposed into intrinsic mode functions (IMFs) using variational mode decomposition (VMD), and a new signal was constructed by combining IMF1 and IMF2. Subsequently, transient energy and waveform similarity fault characteristics are extracted from the constructed signal, and a faulty feeder detection criterion based on multiple transient characteristics fusion is developed. Finally, extensive simulations and field data verify the proposed faulty feeder detection method. The results demonstrate that the method is robust against fault resistance, fault inception angle, fault location, and noise, achieving high accuracy in faulty feeder detection. This method can be widely applied to detect faulty feeders in resonant grounding systems. Full article

Background/Objectives: Squamous cell metaplastic breast carcinoma (SCMBC) is a rare and aggressive breast cancer subtype with limited imaging and prognostic data. This study aimed to characterize the multimodal imaging features, clinicopathological profiles, and prognostic outcomes of SCMBC in a single-center cohort. Methods: We retrospectively analyzed 22 patients with histopathologically confirmed SCMBC treated between January 2012 and May 2025. Clinicopathological profiles, multimodal imaging features, and prognostic outcomes were collected and evaluated. Results: All patients were female (median age 64.5 years; range, 34–82). The majority (59.1%) presented with clinical stage II disease. Axillary lymph node metastasis was present in eight (36.4%) patients at diagnosis, with one case of distant lung metastasis. The mean tumor diameter was 4.24 cm (range, 2.1–11.8). MRI findings (n = 13) included heterogeneous internal structure, a low mean apparent diffusion coefficient (ADC) value of 0.98 × 10⁻³ mm²/s, and frequent necrosis (92.3%). Pathologically, 54.5% of tumors were high-grade, and 81.8% exhibited a triple-negative phenotype. After a median follow-up of 34 months, the 5-year overall survival (OS) rate was 64.3%, while the 3-year disease-free survival (DFS) rate was 42.1%. The recurrence/metastasis rate was 22.7% (5/22), and all five deaths occurred in this subgroup. Conclusions: SCMBC is characterized by suggestive multimodal imaging features, a predominant triple-negative phenotype, and a high risk of early recurrence. Given the exploratory nature of this single-center study with a limited sample size, these findings require validation in larger, prospective cohorts. Early radiological identification and aggressive personalized treatment strategies may improve outcomes for patients with this aggressive disease. Full article

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is increasingly recognized as a contributor to cognitive decline and a potential risk factor for neurodegeneration. Previous studies have also identified various associated comorbidities such as vascular dysfunction, metabolic alterations, and neuroinflammatory changes. Positive airway pressure (PAP) therapy has been associated with cognitive improvement in some studies, but its long-term effects on cognitive function remain uncertain. This study employs a prospective, observational, longitudinal cohort design to examine longitudinal associations between disease severity, PAP therapy and cognition. Additionally, we aim to examine the relationships between cognitive dysfunction, brain structure and associated OSA-related risk factors. A total of 100 eligible participants with mild to severe OSA will be recruited. All participants will undergo comprehensive assessments at baseline and after 12 months, including neurological, pulmonary, and ear, nose and throat clinical examinations, polysomnography, neuropsychological testing, brain magnetic resonance imaging with volumetry, anthropometric measurements, blood and saliva sampling for the assessment of the selected laboratory parameters, gut microbiome analysis, and evaluation of endothelial function and baroreflex sensitivity. This study may improve understanding of how PAP therapy and OSA-related pathophysiological processes influence cognitive outcomes. Full article

A terahertz multifunctional metasurface based on vanadium dioxide (VO₂) and graphene that can switch between waveplate and absorber functionalities is proposed. As the temperature is below 300 K, by electrically controlling the Femi energy of the graphene it can realize half-wave plate (HWP) and quarter-wave plate (QWP) functionalities in the operating bandwidths of both 1.39–2.34 THz and 0.92–2.68 THz, respectively. While the temperature is above 340 K, the dipole resonance between VO₂ and a gold reflector induces absorption. Furthermore, by applying the voltage to graphene, dual-parameter modulation of the amplitude of the transverse electric (TE) waves and the resonance frequency of the transverse magnetic (TM) waves is achieved, the absorption bandwidths of which are 3.65–3.78 THz and 1.41–3.12 THz, respectively. The operating frequencies for HWP, QWP, TE and TM waves can be tuned by changing the electrical field and working temperature. In addition, the incident angles are not sensitive to the performance of the metasurface, confirming its effectiveness even under large-angle incidence. The metasurface with simplicity in design, mature fabrication processes, and comprehensive functionality, has certain promising applications in terahertz optical switches, terahertz spectroscopy systems, modulators, and communication systems. Full article

In cold-region lakes, high organic matter concentrations with low bioavailability are common, yet the underlying causes and stabilisation mechanisms remain unclear. This study conducted a 60-day microbial treatment experiment in Hulun Lake using algae (DOMa), grass (DOMg), and manure (DOMm) as DOM sources. Fourier transform ion cyclotron resonance mass spectrometry and 16S rRNA analysis were employed to characterise DOM composition and bacterial communities. The bioavailability of DOMa, DOMg, and DOMm was 86.1%, 84.08%, and 70.9%, respectively. Differences in degradation cycles were mainly associated with the slowly biodegradable fraction; the half-lives of DOMa, DOMg, and DOMm were 49.51 days, 77.02 days, and 198.04 days, respectively. At the molecular level, proteins and lipids were rapidly utilised by microorganisms, leading to the generation of lignin, condensed aromatic hydrocarbons, and tannins, with many new molecules falling within the carboxylic acid-rich alicyclic molecule (CRAM) region. The overall community succession patterns of different DOM sources were highly similar, with initial DOM composition differences leading to variations in microbial communities during intermediate degradation stages (5~10 days). Moreover, microbiological processes facilitated the convergence of DOM source compositions and the accumulation of refractory organic matter. It is hypothesised that the regional climatic characteristics of the freeze–thaw cycle exacerbate organic matter accumulation by compressing the “effective degradation time”. These findings elucidate the causes of high organic matter and low bioavailability in cold-region lakes. Full article

TC4DT (ELI) is a damage-tolerant titanium alloy characterized by high fracture toughness and slow crack propagation rates, and is, therefore, considered one of the standard materials for model fasteners in modern equipment. However, its high yield strength leads to excessive tool wear and forming defects. This paper presents a complete FE simulation framework to investigate the thread-rolling process of TC4DT(ELI) bolts M16 × 1.5. Using the actual geometries of the workpiece and rollers, an elasto-plastic three-dimensional finite element model was built in ABAQUS/Explicit to perform verification simulations, with the theoretical blank diameter and forming force as the reference benchmarks. The simulation results agreed well with the actual industrial data. This study carried out single-factor analyses of the effect of three important process parameters—the roll speed, friction coefficient, and initial temperature—on the resulting stress–strain distribution, forming force, and thread formation depth. A modal analysis was performed in ANSYS Workbench to check the structural integrity and avoid resonance while operating. According to the results, the optimized parameters decreased the maximum forming force by 14.8% and improved thread filling. Compared with experimental data, the simulation error in the blank diameter was controlled within 1.2%. The present work, a reliable numerical underpinning for replacing expensive and time-consuming trial-and-error processes, forms a basis for high-performance titanium alloy fasteners and assists in the wider application of such fasteners in modern equipment and any advanced manufacturing industries. Full article

Zinner syndrome is a rare congenital anomaly of the male genitourinary tract, characterized by the triad of unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ejaculatory duct obstruction. Owing to its low prevalence and nonspecific clinical presentation, diagnosis is often delayed or incidental, with imaging playing a central role in detection and characterization. This study presents a narrative review with an illustrative case report, aiming to summarize the imaging features of Zinner syndrome, outline the main radiologic differential diagnoses of seminal vesicle cysts, and highlight common diagnostic pitfalls, with emphasis on cross-sectional imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI). The narrative review of the literature highlights that CT and MRI are essential for accurate anatomical localization, characterization of cystic content, and identification of associated genitourinary anomalies. MRI, in particular, provides superior soft-tissue contrast and is considered the reference modality for diagnosis and differential evaluation of male pelvic cystic lesions. Key differential diagnoses include Müllerian duct cysts, prostatic utricle cysts, and ejaculatory duct cysts. As an illustrative example, we report the case of a young adult male presenting with pelvic discomfort, infertility, and mild lower urinary tract symptoms. Imaging findings, including ultrasound and cross-sectional studies, demonstrated a seminal vesicle cyst associated with ipsilateral renal agenesis, consistent with Zinner syndrome. Zinner syndrome should be considered in the evaluation of male pelvic cystic lesions, particularly in the presence of unilateral renal agenesis. Awareness of its characteristic imaging features is essential for accurate diagnosis and appropriate management, with MRI playing a pivotal role in confirming the diagnosis and distinguishing it from other pelvic cystic entities. Full article