Search Results (66)

Addressing the challenges of bulky, low-efficiency sound-insulation materials at low frequencies, this work proposes an acoustic metamaterial based on curve fractal channels. Each unit cell comprises a concentric circular-ring channel recursively iterated: as the fractal order increases, the channel path length grows exponentially, enabling outstanding sound-insulation performance within a deep-subwavelength thickness. Finite-element and transfer-matrix analyses show that increasing the fractal order from one to three raises the number of bandgaps from three to five and expands total stop-band coverage from 17% to over 40% within a deep-subwavelength thickness. Four-microphone impedance-tube measurements on the third-order sample validate a peak transmission loss of 75 dB at 495 Hz, in excellent agreement with simulations. Compared to conventional zigzag and Hilbert-maze designs, this curve fractal architecture delivers enhanced low-frequency broadband insulation, structural lightweighting, and ease of fabrication, making it a promising solution for noise control in machine rooms, ducting systems, and traffic environments. The method proposed in this paper can be applied to noise reduction of transmission parts for ceramic automation production. Full article

This study proposes a novel hybrid connection method for precast concrete shear walls, where the edge walls are connected using grouting splice sleeves and the middle walls are connected using grouted corrugated metallic ducts. To investigate the effects of connection type and axial compression ratio on structural performance, five shear wall specimens were tested under low-cycle reversed loading, with detailed analysis of their failure modes and hysteretic behavior. Based on experimental results and theoretical derivation, a restoring force model incorporating connection type was developed. The results demonstrate that hybrid-connected specimens exhibit significantly improved load-bearing capacity, ductility, and seismic performance compared to those with only grouted corrugated metallic duct connections. A higher axial compression ratio enhances structural strength but also accelerates damage progression, particularly after peak loading. A three-line skeleton curve model was established to describe the load, displacement, and stiffness relationships at key characteristic points, and unloading stiffness expressions for different loading stages were proposed. The calculated skeleton and hysteresis curves align well with the experimental results, accurately capturing the cyclic behavior of the hybrid-connected precast shear walls. Full article

Accurate loss prediction since the preliminary design steps is crucial to improve the development process and the aerodynamic performance of turbines. Initial design phases typically employ reduced-order models in which the different loss-generating mechanisms are assessed through correlations. These correlations are often based on the hypothesis of loss linearity, which assumes that losses from different sources can be summed to obtain the total losses. However, this assumption could constitute an oversimplification, as losses occur concurrently and can interact with each other, potentially impacting overall performance, all the more in low aspect ratio turbomachinery. The aim of this paper is to investigate the role of interactions between different phenomena in the generation of loss. 3D RANS simulations are run on two simplified representations of a turbine blade channel, a curved duct and a linear cascade, and on a real turbine vane. Several inlet and wall boundary conditions are employed to examine loss-generating phenomena both separately and simultaneously. This approach enables the analysis of where and how interactions occur and quantifies their influence on the overall losses. Losses caused by boundary layer–vortex interactions are found to be highly sensitive to the relative positions of these two phenomena. It was observed that the loss linearity assumption may be acceptable in certain cases, but it is generally inadequate for off-design conditions and twisted annular configurations. Full article

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) prediction in high-risk individuals is essential for early detection and improved outcome. While prior studies have utilized pancreatic radiomics for PDAC prediction, the added value of main pancreatic duct (MPD) features remains unclear. This study aims to assess the additional value of features of the main pancreatic duct (MPD) for predicting PDAC occurrence across different timeframes in advance. Methods: In total, 321 contrast-enhanced CT scans of the MPD and pancreas carried out across control, pre-diagnostic, and diagnostic cohorts were segmented, and radiomics were extracted. A support vector machine (SVM) classifier was used to classify the control and pre-diagnostic cohorts, with model performance assessed using area under the receiver operating characteristic (ROC) curves (AUCs) Results: The MPD diameter and volume significantly increased from the control to the pre-diagnostic and diagnostic CT scans (p < 0.05). The addition of features of the MPD to the pancreas improved the PDAC prediction AUC from 0.83 to 0.96 for subjects 6 months to 3 years in advance, from 0.81 to 0.94 for 3–6 years in advance, and 0.75 to 0.84 for 6–10 years in advance of diagnosis. Additionally, integrating MPD radiomics with diameter and volume significantly improved the AUC from 0.81 to 0.88 for subjects 6 months to 3 years in advance. Conclusions: Radiomic features from abdominal CT scans allow PDAC prediction up to 10 years in advance. Integrating MPD features, including diameter and volume, significantly improves PDAC prediction compared to using radiomics of the pancreas alone. Full article

Objectives: To investigate the diagnostic value of various lymphatic imaging techniques for thoracic duct (TD) outlet obstruction in patients with chylous leakage. Methods: A retrospective analysis was conducted on 23 patients with chylous leakage who were radiologically diagnosed with a TD outlet obstruction and underwent a TD exploration and reconstruction between January 2022 and February 2025. Non-enhanced magnetic resonance lymphangiography (MRL), ⁹⁹Tc^m-DX lymphoscintigraphy, and intranodal lymphangiography were employed to detect abnormalities in the central lymphatic vessels. The Receiver Operating Characteristic (ROC) curve was utilized to analyze the diagnostic performance of these imaging methods for TD outlet obstruction in lymphatic disorders. Results: Twenty-three patients (fifteen males and eight females) with chylous leakage were included in this study, with an average age of 59.78 ± 13.08 years. Non-enhanced MRL, ⁹⁹Tc^m-DX lymphoscintigraphy, and intranodal lymphangiography revealed TD outlet obstructions in 13, 17, and 18 patients, respectively. Twenty patients exhibited findings consistent with preoperative imaging during TD explorations; the intraoperative microscopic visualization demonstrated the difficulty of white chyle entering the bloodstream for these patients. The ROC curve analysis indicated that “at least two imaging modalities were positive” and had the highest Area Under the Curve (AUC) value (0.90); “intranodal lymphangiography” and “non-enhanced magnetic resonance lymphangiography” followed closely with respective AUC values of 0.76 and 0.73, and ⁹⁹Tc^m-DX lymphoscintigraphy exhibited a lower AUC value 0.63. Conclusions: The combined utilization of multimodal lymphatic imaging techniques demonstrated a high diagnostic accuracy in identifying TD outlet obstruction in patients with chylous leakage. Full article

Background/Objectives: Intrahepatic cholangiocarcinoma (ICC) is subclassified into small and large duct types. Although these subclassifications may help determine the appropriate treatment strategy, subclassification diagnosis currently depends on postoperative pathological examinations. This study aimed to establish a nomogram to predict ICC subclassifications. Methods: This study included 126 patients with ICC who underwent liver resection. The participants were divided into small and large duct-type ICC groups. A nomogram to predict large duct-type ICC was developed using four diagnostic imaging findings: rim-type enhancement in the early phase, an absence of tumor enhancement in the early phase, the presence of peripheral biliary dilatation due to tumor invasion, the presence of penetrating Glisson’s vessels in the tumor, and two laboratory test results: serum gamma-glutamyl transpeptidase and carbohydrate antigen 19-9 levels. Nomogram performance was also assessed. Moreover, the bootstrap method and calibration plots were used to assess nomogram validity. Results: Seventy and fifty-six patients were pathologically diagnosed with small and large duct-type ICCs, respectively. The area under the curve of the established nomogram was 0.93 and remained 0.91 after Harrell’s bias correction. The sensitivity and specificity of the nomogram developed using the Youden index were higher than those of any of the characteristic imaging findings. Calibration plots demonstrated a strong association between the nomogram and the actual data. Conclusions: We developed a novel preoperative nomogram to predict large duct-type ICC. This nomogram can be clinically useful for predicting the subclassifications of ICCs and may contribute to the establishment of a more appropriate treatment strategy for ICC. Full article

Tapes are widely utilized across various industries, offering versatile solutions for bonding, sealing, and packaging applications. Their ease of use, strength, and adaptability make them essential in manufacturing, construction, and consumer markets. However, the effectiveness of tapes depends heavily on their adhesive performance, which is influenced by factors such as the adhesive layer composition, material compatibility, environmental conditions, and contact parameters. Quantifying adhesive performance through standardized testing is critical to ensuring reliability, optimizing functionality, and meeting industry-specific requirements. Traditional methods, such as peel and shear tests, are commonly used to evaluate the adhesive and shear strength of tapes. However, these methods typically operate at macro-load scales and often use complex sample geometries and significant material quantities. Recently, precision indentation–retraction testing has emerged as a promising technique for accurately quantifying the adhesion and cohesion forces of viscoelastic fluids. This study adapts this method to evaluate and compare the adhesive strength of various commercially available adhesive tapes. The adhesion force and separation energy of five commercial tapes, namely paper masking tape, high-temperature tape, insulation tape, duct tape, box wrapping tape, and double-sided tape, were measured using a Falex Tackiness Adhesion Analyser (TAA) tester, under controlled conditions (approach speed: 0.01 mm/s, retraction speed: 0.1 mm/s, and load: 50 mN). The results indicated that the adhesion force and separation energy varied significantly among the tapes, whereas a different pattern in the indentation–retraction curves was obtained for these tapes. In addition, the significance of difference among the adhesive properties of the tapes was assessed with the use of analysis of variance (ANOVA). This innovative approach not only enhances the precision of adhesive strength measurements but also provides valuable insights into adhesive layer properties, offering a novel tool for research, development, and quality control in tape production. Full article

Savonius turbines are widely used in energy recovery applications, including urban-integrated wind energy systems and Oscillating Water Column (OWC) setups for wave energy conversion. This study explores the use of a ducted Savonius turbine. Experimental tests were conducted on a scaled turbine to evaluate its performance. A Computational Fluid Dynamics (CFDs) model, incorporating Sliding Mesh and Dynamic Fluid Body Interaction (DFBI) techniques, was developed to replicate the experimental conditions. The accuracy of the model was confirmed through validation against experimental data. In total, four conditions were studied: one without a Power Augmenter, one with the Bell-Metha Power Augmenter, and two custom ones obtained by increasing the slope at the end of the Power Augmenters. To facilitate rapid turbine characterization, a fast computational method was developed, allowing the derivation of characteristic curves using only three CFD simulations per configuration. The reliability of this approach was assessed by comparing predictions with experimental results. Developing such a model is crucial, as it enables seamless integration with Reduced-Order Models (ROMs), significantly improving efficiency in evaluating multiple operating points. Compared to traditional experimental testing, this approach provides a faster and more efficient way to obtain performance insights, paving the way for enhanced turbine optimization and real-world deployment. Full article

Background/Objectives: Golgi protein 73 (GP73) is a transmembrane protein expressed by epithelial cells of the bile duct in the normal liver. High serum levels of GP73 have been detected in patients with acute or chronic liver diseases, MASLD, and its measurement has been suggested as a potential biomarker for liver fibrosis staging. We evaluated the utility of GP73 in the diagnosis of MASLD, MASH, and for liver fibrosis staging. Methods: We performed a literature scoping review to map the current evidence about the accuracy of GP73 in patients with MASLD. We searched in Medline and EMBASE for English studies reporting an AUC value of GP73 in diagnosing MASLD and MASH and evaluating GP73 for fibrosis staging. A narrative synthesis of the evidence was conducted. Moreover, we performed an observational study including 84 patients with MASLD, of which 60 were biopsy-confirmed MASH, and different liver fibrosis stages, and 15 healthy controls. Serum GP73 levels were determined using a chemiluminescent assay and reported as mean and standard deviation (SD). Sensitivity (SE), specificity (SP), the area under the receiver operating characteristic (AUROC) curve, and the optimal cut-off value were calculated. Data were considered statistically significant when p < 0.05. Results: Available studies evaluating GP73 in MASLD reported the ability to discriminate MASH from simple steatosis and distinguish patients at different fibrotic stages, but the evidence is still scarce. Our experimental study showed that the serum levels of GP73 were 30 ± 12 ng/mL in MASLD and 32 ± 12 ng/mL in MASH patients and were statistically higher than those of the control group (19 ± 30 ng/mL), increasing from liver fibrosis stage F0 to F4. GP73 levels were significantly higher in patients with significant and advanced fibrosis than controls and no significant fibrosis (p > 0.05). ROC analysis demonstrated that serum GP73 had a good diagnostic potential for MASLD (AUROC 0.85; SE 90%; SP 73%), MASH (AUROC 0.75; SE 82%; SP64%), and significant fibrosis (AUROC 0.7; SE 56%; SP 79%) and was better than other biomarkers for chronic liver diseases. Conclusions: Serum GP73 could support clinicians in the evaluation of patients with MASH and significant fibrosis. Full article

Background: The robotic approach is an appealing way to perform minimally invasive pancreaticoduodenectomy. We compare robotic cases’ short-term and oncological outcomes to a historical cohort of open cases. Methods: Data were collected in a prospective database between 2016 and 2024; complications were graded using the ISGPS definition for the specific pancreas-related complications and the Clavien–Dindo classification for overall complications. Furthermore, the Comprehensive Complication Index was calculated. All patients undergoing pancreaticoduodenectomy were included, except those with acute or chronic pancreatitis, vascular tumour involvement or multi-visceral resections. Only the subset of patients with malignancy was regarded for the oncologic outcome. Results: In total, 100 robotic and 102 open pancreaticoduodenectomy cases are included. Equal proportions of patients have a main pancreatic duct ≤3 mm (p = 1.00) and soft consistency of the pancreatic remnant (p = 0.78). Surgical time is longer for robotic pancreaticoduodenectomy (p < 0.01), and more patients have delayed gastric emptying (44% and 28.4%, p = 0.03). In the robotic group, the number of patients without any postoperative complications is higher (p = 0.02), and there is less chyle leak (p < 0.01). Ninety-day mortality, postoperative pancreatic fistula, and postpancreatectomy haemorrhage are similar. The lymph node retrieval and R0 resection rates are comparable. Conclusions: In conclusion, after robotic pancreaticoduodenectomy, remembering all cases during the learning curve are included, less chyle leak is observed, the proportion of patients without any complication is significantly larger, the surgical duration is longer, and more patients have delayed gastric emptying. Oncological results, i.e., lymph node yield and R0 resection rate, are comparable to open pancreaticoduodenectomy. Full article

Background/Objective: Congenital nasolacrimal duct obstruction (CNLDO) is commonly treated by probing, but recurrence remains a clinical issue. This study investigates the potential role of inflammatory biomarkers, such as the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR), in predicting recurrence after probing in children with CNLDO. Methods: This retrospective cohort study included 172 patients who underwent initial probing for unilateral CNLDO. The patients were then categorized into two groups: those who experienced the complete resolution of symptoms after primary probing, and those who required Ritleng tube intubation due to recurrence following primary probing. Blood samples for calculating inflammatory biomarkers in all subjects were collected during general anesthesia preparation prior to initial probing. NLR, MLR, and PLR values were compared between the groups using the independent samples t-test. The predictive performance of the inflammatory biomarkers for recurrence was assessed using Receiver Operating Characteristic (ROC) curve analysis. Results: A total of 110 patients were included in the probing group, while 62 patients were in the recurrence group. The mean age at the time of the initial probing procedure was 15 ± 4.06 months in the probing group and 15.83 ± 4.02 months in the recurrence group. There was no difference in the duration of the probing procedure between the groups. The mean age at the time of Ritleng tube intubation in the recurrence group was 37.80 ± 13.34 months. The recurrence group exhibited significantly higher values in all analyzed inflammatory markers compared to the probing group, including the NLR (1.12 ± 0.56 vs. 0.86 ± 0.39, p = 0.002), MLR (0.16 ± 0.06 vs. 0.14 ± 0.06, p = 0.005), and PLR (95.13 ± 24.34 vs. 82.23 ± 22.77, p < 0.001). ROC curve analysis indicated that these inflammatory biomarkers demonstrated moderate performance in predicting recurrence. Conclusions: Recurrence following probing in children with CNLDO was associated with complete blood cell count-derived inflammatory biomarkers. The preoperative assessment of these biomarkers may aid in the individualization of disease management and inform the development of new therapeutic strategies. Full article

Background and Objectives: Biliary fistulas (BFs) occur in approximately 3–8% of patients undergoing pancreaticoduodenectomy (PD), and the bile duct diameter ≤ 5 mm is the most important risk factor. The aim of this study was to evaluate the efficacy of biodegradable biliary stents (BSs) in reducing complications in patients undergoing robotic pancreaticoduodenectomy (RPD) with a bile duct diameter of ≤5 mm. Materials and Methods: A retrospective single-centre observational study was conducted. Patients undergoing RPD after the completion of the robotic biliary anastomosis learning curve were included in this study. Only patients with a bile duct diameter ≤ 5 mm were included in the analysis. A prospectively held database was used. The intraoperative time for biliary anastomosis was extracted from surgical videos. Results: Of 30 patients, 20 received no biliary stent (nBS) and 10 received a biodegradable stent (BS). The decision to use a stent was based on product availability. The median operative time for biliary anastomosis was significantly shorter in the BS group compared to the nBS group, at 15 min versus 24 min (p < 0.001). Three patients in the nBS group developed a BF, whereas none were observed in the BS group. No stent migration was observed in any of the patients. Conclusions: The use of biodegradable biliary stents in high-risk biliary anastomosis in RPD appears to effectively reduce the incidence of BFs and may serve as a viable strategy to mitigate early biliary complications. The use of biodegradable stents facilitates a faster and easier biliary anastomosis. These findings suggest a potential benefit of using biodegradable stents in complex biliary reconstruction. However, larger studies are needed to confirm these results. Full article

In order to find a suitable size of sheath duct and a reliable construction method for precast walls, a cast-in-place and five 1/2 scale precast drift-hardening concrete walls reinforced with weakly bonded ultra-high strength SBPDN rebars were fabricated and tested under reserved lateral load and constant compression. The experimental variables were the diameter of sheath ducts (45 mm, 100 mm, and 120 mm), embedded length (20d and 35d; d is the nominal diameter of SBPDN rebars), axial load ratio (0.075 and 0.15), and the construction method. The experimental observations, hysteresis behaviors, envelope curves, residual deformation, crack propagation, and energy dissipation were compared in the study. Moreover, a formula was applied to calculate the bond strength of the sheath duct. The experimental and calculated results revealed that increasing the axial load ratio and embedment length could not enhance the bond strength of the sheath ducts, and increasing the diameter decreased the bond strength significantly. Anchored the SBPDN rebars in smaller sheath ducts separately was a more stable connection method for precast concrete shear walls and provided sufficient drift-hardening capability, even at a large drift level (over 3%). Full article

Background: Cholangiocarcinoma (CCA) is a highly aggressive cancer of the bile ducts with a poor prognosis and limited diagnostic markers. This study aims to investigate the potential of miR-18a and miR-532 as biomarkers for CCA by exploring their correlations with clinical parameters and traditional tumor markers such as CA19.9, CEA, and AFP. Methods: This study involved a cohort of patients diagnosed with CCA. Serum levels of miR-18a and miR-532 were measured and analyzed in relation to various clinical parameters, including age, tumor markers, and histological features. Results: Serum levels of miR-18a and miR-532 were upregulated in patients with extrahepatic cholangiocarcinoma (eCCA) compared to healthy controls (p < 0.05). MiR-18a and miR-532 levels were correlated with each other (p = 0.011, Spearman’s rho = 0.482) but showed no significant correlation with age or traditional tumor markers (CA19.9, CEA, AFP). No significant differences in miR-18a and miR-532 levels were observed concerning tumor localization or histological grading. For predicting tumor resectability, miR-532 at a cut-off point of 2.12 showed a sensitivity of 72.73%, specificity of 81.25%, and an AUC of 71.3%, while miR-18a, at a cut-off of 1.83, had a sensitivity of 63.64%, specificity of 75%, and an AUC of 59.7%. ROC curve analysis suggested moderate diagnostic potential for miR-18a and miR-532, with AUC values of 0.64 and 0.689, respectively. Conclusions: Although miR-18a and miR-532 showed significant upregulation in eCCA patients compared to healthy controls, they did not demonstrate significant associations with key clinical parameters, limiting their effectiveness as standalone diagnostic biomarkers. Further research involving larger, multi-center cohorts and additional molecular markers is necessary to validate these findings and explore the broader diagnostic potential of miRNAs in CCA. Full article

Malignant hilar biliary obstruction (MHBO) can cause obstructive jaundice and/or cholangitis necessitating appropriate biliary drainage. Endoscopic biliary stenting is the first-choice treatment, especially in unresectable cases, owing to its minimally invasive nature and utility. However, the hilar region is complex because of the branching and curving of bile ducts, making strictures in this area more complicated. Therefore, MHBO stenting is challenging, and treatment strategies have yet to be established. Furthermore, recent advances in antitumor therapies have altered the background surrounding the development of stenting strategies. Therefore, it is necessary to understand and grasp the current evidence well and to accumulate additional evidence reflecting the current situation. This study reviews the current status, issues, and prospects of endoscopic stenting for MHBO, especially in unresectable cases. Full article