Search Results (1,338)

Background: Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative to conventional pacing, offering improved ventricular synchrony and clinical outcomes. However, extraction of deeply implanted LBBAP leads remains challenging, particularly in the context of device-related infections. Case Summary: We report two cases of successful extraction of chronically implanted LBBAP leads using a novel technique based on femoral countertraction with pigtail catheters. In the first case, a deep septal implanted 3830 lead was extracted in a patient with persistent bacteremia and suspected device-related endocarditis. Continuous traction was applied to the mid-portion of the lead using a pigtail catheter introduced via femoral access, facilitating safe removal without the use of powered sheaths proximal to the distal tip of the lead. In the second case, three leads (RA, RV, LBBAP) from a cardiac resynchronization therapy with deffibrilation support (CRT-D) system were completely removed in a patient with device extrusion and pocket erosion, using a dual pigtail approach anchored to the atrial and septal leads. Results: In both cases, the technique enabled successful extraction without complications. Procedural times were approximately 70 and 65 min, respectively. In vitro testing suggested that the pigtail catheter applied a sustained moderate traction force (~0.06 kgf), translating to an estimated pressure of 0.85–1.91 kgf/cm² at the septal lead interface. Conclusions: This case series demonstrates that LBBAP lead extraction is feasible using a novel femoral countertraction technique with pigtail catheters. Steady, moderate traction over time may provide a safer alternative to forceful subclavicular extraction, especially in chronically implanted deep septal leads. Further studies are warranted to evaluate the reproducibility, safety, and clinical applicability of this approach. Full article

Deep learning models have demonstrated remarkable success in recognising tipping points and providing early warning signals. However, there has been limited exploration of their application to dynamical systems governed by coloured noise, which characterizes many real-world systems. In this study, we show that it is possible to leverage the normal forms of three primary types of bifurcations (fold, transcritical, and Hopf) to construct a training set that enables deep learning architectures to perform effectively. Furthermore, we showed that this approach could accommodate coloured noise by replacing white noise with red noise during the training process. To evaluate the classifier trained on red noise compared to one trained on white noise, we tested their performance on mathematical models using Receiver Operating Characteristic (ROC) curves and Area Under the Curve (AUC) scores. Our findings reveal that the deep learning architecture can be effectively trained on coloured noise inputs, as evidenced by high validation accuracy and minimal sensitivity to redness (ranging from 0.83 to 0.85). However, classifiers trained on white noise also demonstrate impressive performance in identifying tipping points in coloured time series. This is further supported by high AUC scores (ranging from 0.9 to 1) for both classifiers across different coloured stochastic time series. Full article

Blade tip timing (BTT) is a core technique for investigating the blade vibration of large-scale centrifugal compressors, and identifying the parameters of blade asynchronous vibration is crucial for implementing blade condition monitoring based on the BTT technique. In this study, the multiple signal classification (MUSIC) algorithm and the estimating signal parameters via rotational invariance techniques (ESPRIT) algorithm were first applied separately to identify the asynchronous vibration parameters of centrifugal compressor blades, with their advantages and disadvantages discussed. Subsequently, based on the frequency distribution characteristics in the ESPRIT results, the concept of “frequency distribution rate” was proposed. Finally, the results of the MUSIC algorithm were weighted by the frequency distribution rate, and an improved MUSIC algorithm was proposed. This enhanced confidence in the real frequency in the MUSIC algorithm results. Compared with the strain gauge method, the maximum relative error of the improved algorithm is 0.23%. The improved MUSIC algorithm improves the accuracy of parameter identification for blade asynchronous vibration, which holds great significance for the industrial application of the BTT technique. Full article

The implementation of efficient free-space channels is fundamental for both classical and quantum free-space optical (FSO) communication. This can be challenging for fiber-coupled receivers, due to the time variant inhomogeneity of the refractive index that can cause strong fluctuations in the power coupled into the single-mode fiber (SMF), and requires the use of adaptive optics (AO) systems to correct the atmospheric-induced aberrations. In this work, we present two adaptive optic systems, one using a fast-steering prism (FSP) for the correction of tip-tilt and a second one based on a multi-actuator deformable lens (MAL), capable of correcting up to the third order of Zernike’s polynomials. We test both systems at telecom wavelength both with artificial turbulence in the laboratory and on a free-space channel, demonstrating their effectiveness in increasing the fiber coupling efficiency. Full article

Background/Objectives: Femoral neck and proximal femur fractures in the elderly can result from low-energy trauma due to osteoporotic changes and contribute significantly to increased morbidity and mortality. Despite various treatment options, closed reduction and internal fixation (CRIF) with intramedullary nails has become the predominant approach. While a minimally invasive approach reduces complications and speeds recovery, this outcome is not always feasible in practice. The primary surgical goal remains achieving a stable and precise fracture reduction, favoring CRIF when possible. Our study aims to evaluate the clinical, radiological, and functional outcomes of patients operated on using the Wide-Awake Local Anesthesia No Tourniquet (WALANT) technique. Methods: Patients who underwent surgery for intertrochanteric femur fractures between June 2019 and June 2021 were analyzed. Patients who were between 75 and 90 years old and had undergone surgery with a proximal femoral nail (PFN) were included in the study. Patients were excluded if they required general anesthesia, if an acceptable reduction could not be achieved with the PFN, if they did not attend the last follow-up examination, or if the follow-up period was <4 years. Patients were functionally assessed using the Harris hip score at the 6th month and at the last follow-up and using the visual analog scale at the surgery, at the 4th hour after surgery, and at the time of discharge. For radiological assessment, the classification of reduction quality and the measurement of the tip–apex distance were used. Results: Forty patients (22F/18M) were included in the study. Their mean age was 83.0 ± 2.9 years. The mean time from trauma to surgery was 6.8 ± 2.3 h. Patients were mobilized on average 1.53 ± 0.8 h after surgery, and the mean hospitalization time was 27.4 ± 8.1 h. No statistically significant decrease in hemoglobin value was observed before or after surgery (p = 0.476). The Harris hip score was 73.3 ± 3.2 at the 6th month postoperatively and 74.9 ± 2.5 at the last follow-up (p = 0.296). The reduction quality was found to be poor in only two patients. Conclusions: The WALANT technique’s promising results in terms of pain management, blood loss control, and early mobilization show that it is a viable alternative to conventional anesthesia methods in geriatric hip fractures. Full article

To investigate the damage degradation of recycled concrete under mesoscale morphology and the critical expansion force of concrete cracking following sulfate wet–dry cycles, an experimental sulfate wet–dry cycle was designed. In situ scanning of recycled concrete was conducted using X-ray computed tomography (CT). Analysis of the CT images revealed the relationship between the gray scale changes and the sulfate salt wet–dry cycle, along with pore alterations and crack propagation in recycled concrete. A CT image analysis method based on grayscale inversion for crack propagation was developed. By integrating sulfate attack with fracture mechanics, this study explored the phenomenon of pore expansion in recycled concrete subjected to dry–wet cycling tests. The concrete fracture criterion provided the basis for determining the critical expansion force of recycled concrete after the wet–dry cycles. Results indicated that as the duration of sulfate wet–dry cycles increased, the gray scale first increased and then decreased. On the 40th day of the cycling test, the average grayscale value increased by 10.4%. The number of pores in recycled concrete continuously decreased, pore size diminished, and cracks appeared on the specimen’s weak surface. The use of gray scale changes to reveal the degradation of recycled concrete after sulfate wet–dry cycles proved to be both feasible and effective. As the length of the interface crack increased, the stress intensity factor at the crack tip also increased, while the critical expansion force decreased. Additionally, as the pore diameter increased, the stress intensity factor at the crack tip rose. The critical expansion force of a symmetric crack at the edge of a pore was 53 times greater than that of a single crack. Full article

Quercus petraea subsp. pinnatiloba is a narrowly distributed oak taxon in southeastern Türkiye, and its taxonomic position has long remained uncertain. This study aims to clarify its distinctiveness by integrating morphological, molecular, and biogeographical evidence. Principal Component Analysis (PCA) and Stepwise Discriminant Analysis (SDA) of 14 leaf traits revealed that subsp. pinnatiloba constitutes a morphologically stable and distinctly differentiated group from other Q. petraea subspecies and closely related taxa, characterized by key diagnostic traits such as petiole length (PL), lamina length (LL), length of leaf blade at its broadest point (WP), and lobe width at the tip of the widest lobe (LW). Phylogenetic analyses based on nuclear ITS and plastid markers (rbcL, psbA-trnH) confirmed its placement within sect. Quercus, yet consistently distinguished it genetically from other subspecies for the first time. Molecular dating (BEAST) suggested divergence in the Miocene (11 Mya with 95% HPD 3.01, 20.95) while RASP biogeographical analysis indicated an origin in the Euro-Siberian region with later dispersal into the Mediterranean. These integrative results support its recognition at species rank as Quercus pinnatiloba, clarifying its phylogenetic placement and underscoring the conservation importance of this lineage. Full article

Platycerium bifurcatum is one of the most widely cultivated ornamental fern species worldwide and a valuable component of the biodiversity of pantropical forests. In addition to its photosynthetic function, the sporotrophophyll leaves of this species periodically develop a large, clearly demarcated sporangium at the leaf tips, enabling physiological and biochemical measurements both in the active sporulation part and in the non-sporulating leaf area. The aim of this study was to assess anatomical changes, determine thermal effects and the content of selected phytohormones, and analyze the spatial distribution of pigments in the sporophilic and trophophylic part of the same leaf during spore formation. The study utilized fluorescence microscopy, isothermal microcalorimetry, Raman mapping, and ultra-high-performance liquid chromatography coupled with a Triple Quad LC/MS analyzer. The results revealed significant physiological differences between the sporulating and non-sporulating leaf areas. For the first time, differences in thermogenesis within the two leaf regions accompanying sporulation and linked to the sporangium development stage have been demonstrated in ferns. Increases in gibberellins (GA3, GA4, and GA6), auxin (indole-3-butyric acid), (±)-cis, trans-abscisic acid, and abscisic acid glucose ester were observed in the sporophilic part of the leaf, as well as fluctuations in phytohormones in the trophophilic part, indicating internal metabolite relocation within the leaf. Raman analysis and 2D mapping revealed local lignin accumulation and fluctuations in carotenoid levels during spore maturation. The results of this study demonstrate physiological variation within a single leaf and the mechanisms accompanying sporulation, which provide a better understanding of fern adaptive strategies. Full article

Purpose: To evaluate the efficiency and safety of high-fluidics ultrasound emulsification using slim-shaft-strong-bevel (SSSB) tip technology for nucleus workup through mini- and micro-incisions. Materials and Methods: 77 patients underwent immediate sequential bilateral cataract surgery using high-flow-high-vacuum easyTip^®2.2 (“eT2.2”) or infusion-assisted (“Hybrid”) easyTip^®COMICS (“eT1.6 iaCOMICS”) coaxial phacoemulsification. Surgical time (ST), Effective Phacoemulsification Time (EPT), and fluid consumption (FC), central corneal thickness (CCT), and endothelial cell count (ECC) were recorded. Results: 50 patients completed the 6 months follow-up. Preoperatively, groups did not differ in nuclear hardness, CCT, or ECC. The median ST for Conquer with eT2.2 phaco was 49 s, with eT1.6 iaCOMICS phaco 57 s (p = 0.021). The median total EPT was 8.3 and 8.0 (p = 0.882), and the median EPT for Conquer was 4.0 and 4.1, respectively (p = 0.812). The median FC for Conquer was 21 mL with the eT2.2 and 22 mL with the eT1.6 iaCOMICS phaco (p = 0.29), and the overall FC was 29 mL and 33 mL, respectively (p = 0.105). Mean CCT was 561 ± 42 µm and 563 ± 45 µm on day 1 (p = 0.835), 539 ± 33 µm and 542 ± 34 µm at 1 week (p = 0.714), and 536 ± 31 µm and 541 ± 33 µm at 6 months (p = 0.55), respectively. Mean ECL at 6 months was 2.80 ± 7.28% and 3.41 ± 8.25% (p = 0.725). Conclusions: When compared to previously published results obtained with a standard non-waisted phaco needle and lower fluidics and with the waisted easyTip^®2.2 run with intermediate fluidics, ultrasound-assisted high-fluidics phacoaspiration with the easyTip^®2.2 through a 2.2 mm incision and the easyTip^® COMICS through a 1.6 mm incision with infusion-assistance significantly improved efficiency of nucleus workup by reducing ultrasound energy and infusion fluid consumption, with minimal transient corneal stroma swelling and low endothelial cell loss. Full article

Capsule-based self-healing technologies offer a promising solution to extend pavement service life without requiring external activation. The effect of the capsule content on the mechanical behaviour of self-healing asphalt mixtures still needs to be understood. This study presents a numerical evaluation of the isolated effect of incorporating capsules containing encapsulated rejuvenators, at different volume contents, on the stiffness and strength of asphalt mixtures through a three-dimensional discrete-based programme (VirtualPM3DLab), which has been shown to predict well the experimental behaviour of asphalt mixtures. Uniaxial tension–compression cyclic and monotonic tensile tests on notched specimens are carried out for three capsule contents commonly adopted in experimental investigations (0.30, 0.75, and 1.25 wt.%). The results show that the effect on the stiffness modulus progressively increases as the capsule content grows in the asphalt mixture, with a reduction ranging from 4.3% to 12.3%. At the same time, the phase angle is marginally affected. The capsule continuum equivalent Young’s modulus has minimum influence on the overall rheological response, suggesting that the most critical parameter affecting asphalt mixture stiffness is the capsule content. Finally, while the peak tensile strength shows a maximum reduction of 12.4% at the highest capsule content, the stress–strain behaviour and damage evolution of the specimens remain largely unaffected. Most damaged contacts, which mainly include aggregate–mastic and mastic–mastic contacts, are highly localised around the notch tips. Contacts involving capsules remained intact during early and intermediate loading stages and only fractured during the final damage stage, suggesting a delayed activation consistent with the design of healing systems. The findings suggest that capsules within the studied contents may have a moderate impact on the mechanical properties of asphalt mixtures, especially for high-volume contents. For this reason, contents higher than 0.75 wt.% should be applied with caution. Full article

To further improve machining accuracy under the constrained conditions of multi-axis dynamic response, current research is focusing on the control of CNC machine toolpaths, with contour error as the target. While extant approaches analyze positions solely at PLC sampling nodes, they neglect inter-sample toolpath fluctuations induced by velocity deviations. This paper proposes a servo state-based polynomial interpolation model predictive control that predicts real-time toolpath behavior by utilizing servo axis states. The polynomial interpolation of servo states (e.g., position/velocity feedback) enables high-fidelity toolpath prediction between PLC nodes, overcoming the limitation imposed by the sampling gap. Experimental validation on a five-axis motion platform with S-shaped trajectories demonstrates that, without extending the prediction horizon of the model predictive control method, the proposed method reduces contour error by approximately 20% at the tool tip and 40% in tool orientation, while decreasing contour error fluctuations by around 60% compared to conventional model predictive control method. Full article

Background and Objectives: Transpyloric (TP) feeding tube placement is a viable nutritional strategy in low birth weight infants (LBWIs) with severe gastroesophageal reflux or feeding intolerance. However, technical challenges are encountered in patients of this age group due to their small body size and the limited availability of appropriately sized equipment. Materials and Methods: We retrospectively reviewed 15 endoscopic TP tube placements performed in 12 LBWIs weighing less than 2.5 kg between May 2017 and March 2025. Emphasis was placed on procedural techniques, equipment selection, and troubleshooting strategies for successful bedside execution. Results: All procedures were performed without the use of additional accessories, by advancing a feeding tube preloaded with a guidewire under direct visualization provided by a 5.5 mm outer diameter endoscope. All procedures were technically successful, including 14 performed at the bedside using a portable endoscope. A 6 or 8 Fr feeding tube loaded with a soft-tipped guidewire was advanced through the pylorus under direct endoscopic visualization. The average body weight at the time of the procedure was 1950 ± 296 g. No complications such as mucosal injury, perforation, or tube dislodgement occurred during the procedure. The average enteral feeding volume increased from 33.4 ± 52.8 cc/kg to 92.0 ± 44.4 cc/kg within 7 days. Full enteral nutrition was achieved in all surviving patients within three weeks. The feeding tube remained in place for a mean duration of 26.1 ± 19.2 days. Conclusions: Endoscopic TP tube placement in LBWIs can be safely and reliably performed at the bedside with appropriate technical modifications. It facilitates earlier advancement to full enteral nutrition and may serve as a viable option for LBWIs unresponsive to standard feeding methods. Full article

Hydraulic concrete is prone to cracking and interactive propagation under complex stress, threatening its structural integrity and service life. To address limitations of traditional numerical methods (e.g., mesh dependency in FEM) and imprecision of existing meshless methods for characterizing multi-fissure interactions, this study improved SPH to model double-crack interactions in hydraulic concrete under three-point bending and clarify the underlying mechanisms. A modified SPH framework was developed by introducing a failure parameter (ξ) to refine the kernel function, enabling simulation of particle progressive failure via the Mohr–Coulomb criterion; a three-point bending numerical model of concrete beams containing double precast fissures (induced and obstacle) was established, with simulations under varying obstacle fissure angles (α = 0–75°) and distances (d = 0.02–0.06 m). The results show that the obstacle fissure angles significantly regulate the crack paths: as the α increases, the tensile stress concentration shifts from the obstacle fissure’s middle to its ends, causing cracks to deflect toward the lower end, with a reduced propagation length and lapping time; at an α = 75°, the obstacle fissure’s lower tip dominates failure, forming an “induced fissure–lower end of obstacle fissure–top” penetration mode. The fissure distances affect the stress superposition: a smaller d (e.g., 0.02 m) induces vertical propagation and rapid lapping with the obstacle fissure’s lower end, while a larger d (e.g., 0.06 m) weakens the stress at the induced fissure tip, promoting horizontal deflection toward the obstacle fissure’s upper end and transforming the failure into “upper-end dominated.” This confirms that the improved SPH method effectively simulates crack behaviors, providing insights into multi-fissure failure mechanisms and theoretical support for hydraulic structure crack control and safety evaluation. Full article

Fracture toughness anisotropy is a key concern in IN718 components produced by Laser Powder Bed Fusion (LPBF), due to their strong crystallographic texture and characteristic lamellar microstructure. In this study, the effect of grain orientation on fracture toughness was evaluated by testing two LPBF IN718 builds with the same laser scanning strategy (R0), but with two different orientations: vertical (R0-0) and 45° inclined (R0-45) relative to the build direction. The mechanical response was assessed through compact tension (CT) tests following ASTM E399 and ASTM E1820 standards. Results show that the R0-45 specimens exhibited a fracture toughness nearly 2.5 times higher than R0-0 specimens. Detailed microstructural analysis, supported by EBSD and SEM, reveals that the higher toughness in the R0-45 orientation is linked to a combination of smaller effective grain size along the crack path, higher levels of geometrically necessary dislocations (GND), and increased kernel average misorientation (KAM), which collectively enhance plastic accommodation and crack-tip shielding. These findings support and reinforce the established understanding of the relationship between microstructure and anisotropic fracture behavior in LPBF IN718, facilitating its practical application in the design and orientation of additively manufactured components. Full article

The limitations of traditional fossil fuels have prompted researchers to develop new renewable energy technologies. Raindrop impact energy has become a research hotspot in the field of energy harvesting due to its wide distribution and renewability, especially in the self-energy supply of microrobots. The energy harvester is installed on the robot, utilizing piezoelectric-energy-harvesting technology to achieve self-energy supply for the robot, but the efficiency of existing raindrop energy harvesters is unsatisfactory. In order to better collect the impact energy of raindrops and broaden the application of piezoelectric energy harvesters in the field of autonomous energy supply of robots, inspired by the vibration generated by raindrop excitation of plant leaves in nature, a raindrop energy harvester for autonomous energy supply for robots was proposed through the bionic leaf design, a mathematical model was established for numerical simulation analysis, and the effects of excitation position, excitation height, petiole length and excitation rate on the output performance of the harvester were analyzed. Numerical simulation and experimental test results show that the piezoelectric energy harvester has a higher output at the excitation position at the tip. The higher the excitation height of the water droplet, the higher the output voltage. Increasing the length of the petiole can significantly improve its performance output, and at the same time, the raindrop excitation rate will also affect its output to a certain extent. Full article