Search Results (2,461)

Background and Objectives: Hysterectomy is one of the most frequently performed gynecological surgical procedures worldwide. It is well established that the laparoscopic approach offers better outcomes for patients compared to abdominal hysterectomy. However, the technique for vaginal cuff closure during laparoscopic hysterectomy (TLH) remains insufficiently standardized in the international literature. Based on our results, we aim to demonstrate that closure of the vaginal cuff using a figure-of-eight suture is a sufficient, reproducible, time-efficient and safe method during total laparoscopic hysterectomy. Materials and Methods: Our retrospective observational study analyzed 173 patients who underwent a TLH from January 2016 to December 2021 at the University of Debrecen, Department of Obstetrics and Gynecology. Standardized surgical steps were applied in all cases (ligation of the uterine arteries at their origin, fenestration of the broad ligament above the ureter), and the vaginal cuff was closed laparoscopically with an absorbable suture, incorporating vesicovaginal fascia, vaginal mucosa and uterosacral ligaments. Patient demographics, operative data, and perioperative outcomes were extracted and analyzed. Results: TLH was successfully performed in 173 cases, and no conversion to open surgery was necessary. The mean age of the patients was 51.4 (23–86) years, the median body mass index (BMI) was 26.9 (16.9–45) kg/m², and the operative time was 92 (35–240) minutes. The mean uterine weight was 151 (16–440) g. The mean hemoglobin drop was 15.8 (0–44) g/L after the surgery. Regarding complications, ureteral injuries occurred in two cases (1.2%). One patient (0.6%) required relaparotomy due to rectosigmoid perforation. Postoperative complications included vaginal cuff dehiscence in two cases (1.2%), with one patient (0.6%) requiring resuturing, fever in six cases (3.5%), vaginal discharge in four cases (2.3%), and vaginal bleeding in one case (0.6%). Pulmonary embolism occurred in one patient (0.6%). Three patients (1.7%) required blood transfusion based on postoperative blood counts. Conclusions: Our results demonstrate an acceptable operative time and a low rate of postoperative complications, suggesting that closing of the vaginal cuff with a figure-of-eight suture is a sufficient and safe technique. This method can be reliably reproduced and incorporated into the standardized steps of total laparoscopic hysterectomy. Full article

Necrotising enterocolitis (NEC) remains an important disease for neonatologists, with diagnostic and management challenges and impacts on mortality and neurodisability. NEC can present in a non-specific way, and differentiating from late-onset sepsis (LOS), focal perforation (FIP) and feed intolerance can be difficult. Biomarkers have been extensively explored as a way to help more definitively identify NEC or rule it out. Many biomarkers that have been studied are blood biomarkers, and several other extensive reviews of biomarkers in NEC exist. In this narrative review, we focus on non-invasive samples, namely stool, urine and saliva, and on tests that are already available as point-of-care tests (POCTs) or are likely to be available as POCTs soon given current technologies. Faecal calprotectin and urinary intestinal fatty acid-binding protein (IFABP) have the most data to currently support their use in larger multi-centre studies and appear most likely to achieve translation into clinical practice. Saliva appears the most under-researched potential source of a non-invasive POCT for a biomarker for NEC. For faecal calprotectin and urinary IFABP, data that are most lacking relate to specificity, particularly the performance of these tests to differentiate NEC from FIP or LOS (occurring in the absence of NEC). We suggest a study design to facilitate moving towards the clinical use of non-invasive biomarkers in NEC. Full article

Background and Objectives: Extramammary Paget’s Disease (EMPD) of the perineal region is a rare intraepidermal adenocarcinoma requiring wide excision, resulting in extensive defects that are challenging to reconstruct while preserving contour and function. This descriptive case series evaluated a reconstructive selection strategy using pedicled superficial circumflex iliac artery perforator (SCIP) flaps and pedicled anterolateral thigh (ALT) flaps for perineal defects following wide excision of EMPD. Materials and Methods: This retrospective case series reviewed patients with perineal EMPD who underwent wide excision followed by reconstruction using pedicled SCIP flaps or pedicled ALT flaps. Patient demographic and lesion characteristics, operative and flap characteristics, post-reconstruction complications, oncologic outcomes, and satisfaction were analyzed. Results: 15 patients (mean age 63 years, SD 7.3) were included in this case series. Ten patients underwent reconstruction using pedicled SCIP flaps (mean 106 cm², SD 23.3), and five patients with pedicled ALT flaps (mean 245.2 cm², SD 41.2). All flaps survived, but one patient developed limited partial necrosis managed with secondary healing. During a mean follow-up of 17.7 months (SD 1.3), one patient (6.7%) developed recurrence and eventually distant metastasis resulting in death. Among the 14 surviving patients, 13 (92.9%) reported overall satisfaction with cosmetic and functional outcomes assessed using a non-validated ordinal scale. Conclusions: Pedicled SCIP and ALT flap reconstruction provides reliable, well-vascularized tissue coverage for perineal EMPD defects and achieves generally favorable short-term outcomes. The choice between flap types should be tailored to the defect size, location, and patient characteristics. Full article

This work develops a locally adaptive isogeometric phase-field framework for two-dimensional quasi-static brittle fracture using cubic $C^1$ polynomial splines over hierarchical T-meshes (PHT-splines). The aim is not to introduce a new crack-density functional or a new degradation law, but to provide a consistent variational-to-discrete setting in which second- and fourth-order phase-field regularizations can be treated within the same locally refined spline framework. Starting from the energy functional, the formulation is carried through admissible weak forms to the corresponding discrete residual equations. The second-order formulation is posed in an $H^1(\mathrm{\Omega })$ setting, whereas the fourth-order model is treated directly through a Laplacian-based $H^2(\mathrm{\Omega })$-compatible approximation without auxiliary phase-field variables. The formulation combines history-field irreversibility, the tension–compression split of the elastic energy, and an adopted cubic degradation law with $s={10}^{-4}$, whose nonlinear tangent contribution is handled by a Taylor-stabilized staggered Newton scheme. Numerical tests on a single-edge notched tensile benchmark and a notched perforated beam under asymmetric bending show that local refinement captures the fracture zone while maintaining critical-load deviations of about $0.8\%$ and $0.3\%$, respectively, relative to the reference critical loads used for the two benchmark problems. The contribution therefore lies in the coherent coupling of higher-order regularity, admissible weak forms, local PHT-spline adaptivity, and stabilized nonlinear degradation treatment within a spline-based phase-field fracture implementation. Full article

Additively manufactured composite architected discs offer a potential route for producing lightweight semi-finished blanks that can subsequently be shaped by conventional forming processes. However, the relationship between infill architecture, feature size, and deep-drawing formability remains poorly understood. This study investigates the deep-drawing response of material-extruded short-fibre-reinforced polymer composite discs by combining experimental tests and finite element simulations. Four infill strategies, namely perforated body, re-entrant, square and triangular, were first compared at drawing depths of 10 and 20 mm. The perforated body and re-entrant geometries were successfully formed at 10 mm, whereas only the perforated body withstood 20 mm without macroscopic failure. A second campaign focused on perforated discs with hole diameters of 2.5, 5, 7.5 and 10 mm. All configurations were drawable at 10 mm, while the 2.5 mm case failed at 20 mm. Statistical analysis confirmed that hole diameter significantly affected both retained cup height and side-hole aspect ratio. At 20 mm, larger holes reduced local ovalization but increased elastic recovery, leading to lower retained cup height. FEM simulations were used as an interpretative first-order model. They supported the experimental trends by comparing deformation modes, tensile/compressive stress redistribution, forming energy and strain localization. The results show that the formability of architected composite blanks is governed not only by material volume or porosity but by the ability of the internal architecture to accommodate deformation through a suitable balance between local stiffness and geometric compliance. These findings provide design-oriented guidelines for the development of additively manufactured architected blanks intended for hybrid additive–forming manufacturing routes. Full article

Piezoelectric pressure sensors for dynamic monitoring face a trade-off between charge output and measurement range, and existing high-sensitivity designs are largely confined to narrow ranges. This study presents a composite layered piezoelectric pressure sensor in which a 316L stainless-steel diaphragm drives a centrally suspended PZT-5H wafer supported by a perforated alumina gasket, with the wafer thickness and cavity radius optimized under a 10 MPa full-scale stress constraint. Over 0–10 MPa, quasi-static calibration gave a highly repeatable quadratic pressure–charge relationship ($R^2=0.99995$) with a maximum residual below 1% FS. The sensitivity is pressure-dependent: the secant sensitivity increased monotonically from 3.16 pC/kPa at 1 MPa to 5.36 pC/kPa at 10 MPa, reflecting a stress-stiffening response rather than a measurement tolerance band. The output deviation remained within 3% from 25 °C to 150 °C. Shock-tube testing yielded a resonance of ∼50 kHz and a mutually consistent 10–90% leading-edge interval of 10.12 $\mathsf{\mu }$s. Combining high charge sensitivity over a wide 0–10 MPa range with a fast transient response and stable operation up to 150 °C, the proposed sensor is suited to dynamic pressure-pulsation monitoring in fluid-power and thermal and power-plant fluid systems. Full article

Geodiversity, particularly topographical gradients, significantly influences ecosystem function by creating heterogeneous environmental conditions. This study examined how local-scale microtopography and litter bag perforation affected leaf litter decomposition rates in a humid-temperate secondary forest. We categorized microtopography into ridge, valley, southwest slope, and northeast slope, with relative height differences of around 20 m. Using the litter bag method comparing non-perforated (1 mm mesh) and perforated (with 6 mm holes) bags, we measured leaf litter mass loss and moisture content of Quercus serrata over 6 and 12 months. While microtopography caused only slight differences in leaf litter moisture content, it significantly influenced decomposition rates. Leaf litter mass loss was lower in valley microtopography compared to the southwest slope and ridge microtopography. We infer that topographical differences in unmeasured microclimatic factors, such as solar radiation and soil temperature, may have potentially driven these spatial variations in decomposition. Furthermore, because the litter bag perforation did not significantly promote further mass loss, our results suggest that baseline decomposition driven by organisms capable of passing through the 1 mm mesh (e.g., microbes and meso/microfauna) might have been sufficiently high in this environment. These findings highlight that local-scale microtopographical differences enhance the spatial heterogeneity of leaf litter decomposition in forest ecosystems. Full article

Dynamic shading systems offer a promising approach to improving daylight and visual comfort in hot climates. The present work aims to enhance hourly daylighting performance by optimizing useful daylight illuminance (UDI_{500~1000 lx}), illuminance uniformity (Uo), and daylight glare probability (DGP). Radiance and SPEA-2 enable the identification of optimal solutions for corrugated, perforated, and separated trapezoid shading systems. The first multi-objective optimization selected a 15° slat angle, yielding an average illuminance of approximately 782.22 lx, a Uo of 0.7229, 100% coverage in the UDI_{500~1000 lx} range, and a DGP of 0.3324. Fully automatic control of the upper, central, and lower facade sections addressed issues of UDI_{300~500 lx} in June and UDI_{1000~2000 lx} in December. Corrugated shadings achieved over 90% for UDI_{500~1000 lx} during most investigated equinox and solstice conditions, with a minimum Uo of 0.79 in March and approximately 0.6 in December. Perforated inclined panels improved UDI_{500~1000 lx} for morning and afternoon. The fully automated trapezoid-separated shading system increased UDI_{500~1000 lx} coverage to at least 99.47% at 15:00 in March, 92.95% at 15:00 in June, and 92.06% at 12:00 in December, with DGP within imperceptible glare. The methodological scope was limited to a selected office space and point-in-time simulations from 10:00 to 15:00 on representative equinox and solstice days; therefore, the results should be interpreted as simulation-based design guidance rather than full annual or experimentally validated performance. Full article

The valorization of post-consumer waste materials is an important strategy for reducing environmental impact and supporting circular material use. In this study, lightweight sandwich composites were developed using recycled paper and cardboard as core materials, producing sustainable panels for thermal and acoustic insulation. Core panels were manufactured from 100% paper, 100% cardboard, and a 50–50% paper–cardboard mixture. Environmentally friendly foaming agents were added to increase porosity and reduce density. The cores were subsequently combined with 3 mm medium-density fiberboard (MDF), 1 mm oak veneer, and date palm midrib fibers to provide different surface characteristics. The resulting sandwich composites were evaluated through standardized measurements of thermal conductivity and sound absorption coefficients. Microstructural characteristics were investigated using stereomicroscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX). The results indicate that both the core composition and the type of face layer influence their performance. Whilst composites with cardboard-rich cores had higher porosity and better thermal insulation, introducing perforations and increasing the panel thickness improved sound absorption. The findings demonstrate that recycled paper and cardboard can be effectively used as sustainable raw materials to produce lightweight sandwich composites, tested at material scale, for non-structural interior insulation/acoustic panels. Full article

Background: Self-expanding esophageal stents (SEMS) are widely used in the management of malignant dysphagia and a variety of benign esophageal conditions. Although stent migration is a well-recognized complication, late migration -defined as occurring ≥4 weeks after stent placement- is less well characterized and may result in severe, life-threatening emergencies. These events are frequently underrecognized and not consistently addressed within current surveillance practice. Methods: A systematic review was conducted in PubMed/MEDLINE, Embase, and Scopus databases focusing on acute clinical presentations following late esophageal stent migration. Results: Out of 343 unique articles, 53 studies were included, involving 53 patients with a median time to presentation of 3 months after stent placement, and 12.5% of cases occurring more than one year later. The gastrointestinal tract was the most frequent site of migration (64.2%), followed by airway/respiratory (15%), thoracic (13.2%), and vascular structures (5.7%). Clinical presentations included small bowel obstruction (30.2%), gastrointestinal or thoracic perforation, respiratory failure, sepsis, and catastrophic hemorrhage. Surgical intervention was required in most cases. Overall mortality was 28.3%, with especially poor outcomes in cases complicated by vascular or airway involvement. Conclusions: Late esophageal stent migration represents a clinically significant but underrecognized cause of acute surgical emergencies. Risk-adapted surveillance, prompt diagnostic imaging, and early multidisciplinary management are essential to improve outcomes and enhance the long-term safety of esophageal stent therapy. Full article

The increasing power density of modern electronics demands more efficient thermal management. Heat sinks with sinusoidal fins remain understudied, and the combined effect of perforations and variable fin spacing on transient performance has not been systematically quantified. This numerical study, conducted using ANSYS Fluent 2025 R2, analyzes three sinusoidal fin configurations under forced convection (3–5 m/s): solid fins (Case A), perforated fins (Case B), and perforated fins with alternating spacing of 2 mm and 4.5 mm (Case C). The base was maintained at 60 °C during a 20 s transient period. A mesh with an average skewness of less than 0.25 ensured numerical convergence. Case B showed remarkable uniformity in the base temperature (variations < 1 °C), in contrast to Case A (variations of up to 14.17 °C), due to a thermal boundary layer restart effect induced by the perforations. Case C reached the highest heat dissipation temperatures (up to 54.64 °C at 3 m/s), representing a 47.2% increase compared to Case A, indicating more effective heat extraction with this type of separate fin. The critical transient window occurs within the first 5 s (>85% of the total temperature rise). A vertical temperature gradient of 1.19 °C/mm was observed near the base. Although the perforations reduced the heat transfer area by 5.94%, the induced turbulence compensated for this loss. Sinusoidal fins with perforations and variable spacing significantly improve convective heat removal. Full article

Background: Colorectal cancer (CRC) remains a significant global health challenge, particularly because of its associated complications. Among these, tumor perforation is a critical event linked to increased postoperative morbidity and mortality. This study aimed to evaluate and compare the surgical outcomes of patients with perforated colon cancer versus those with non-perforated colon cancer. Methods: A retrospective comparative study was conducted in the visceral surgery departments of Hassan II University Hospital in Fes, Morocco, including 198 patients who underwent surgical treatment for colon cancer between January 2014 and December 2022. Statistical analyses included descriptive assessments and comparative tests using the Chi-square and Student’s t-tests, with a p-value < 0.05 considered statistically significant. Results: Of the 198 patients, 22 (11%) presented with perforated colon cancer. Laparotomy was the predominant surgical approach in the perforated group (86.4%), whereas laparoscopy was more frequently used in non-perforated cases (56.2%, p = 0.001). Stoma creation was significantly more common in perforated cases (72.7% vs. 4%, p < 0.001), with a notably higher rate of stoma closure failure in the perforated group (37.5% vs. 0%, p < 0.001). Postoperative complications were also more frequent in the perforated group (36.4% vs. 13.6%, p = 0.006), with higher rates of R2 resections (27.3% vs. 0.6%, p < 0.001) and tumor recurrence (27.3% vs. 4.5%, p < 0.001). The mean hospital stay was significantly longer in patients with perforated cancer (11 days vs. 5 days, p < 0.001). Conclusions: This comparative study demonstrates that patients with perforated colon cancer are more likely to require a Hartmann’s procedure, to have prolonged intensive care unit stays, to experience higher rates of postoperative complications, to undergo R2 resections, and to have a greater incidence of tumor recurrence. A non-significant trend toward higher 30-day mortality was also observed. Full article

This study explores the similarity of the fragmentation effect of a reactive inner core PELE (RIC-PELE) when penetrating a steel plate by measuring the broken length of the jacket after perforating the steel plate and the dispersion radius of the jacket fragments behind the steel plate. Based on the dimensional theory, the dimensionless functions of these two physical quantities were analyzed and established. On the basis of verifying the validity of numerical simulation, the penetration and deflagration damage effects of five scale models were simulated on the ANSYS/Autodyn 17.0 software platform, and the dimensional analysis was verified. In the obtained dimensionless functions, the independent variables are all geometric dimensionless quantities. The simulation results reveal that, within the impact velocity range of 900–1900 m/s, the dimensionless broken length of the jacket and the dimensionless dispersion radius of jacket fragments behind the target are approximately equal in different scale models at the same velocity; these values fall within error margins of ±7% and ±9% of the reference model, respectively, and both dimensionless quantities exhibit an approximately linear positive relationship with impact velocity. This indicates that when ignoring the size effect caused by the strain rate effect of the materials, the geometric similarity law of the fragmentation effect of a RIC-PELE penetrating a steel plate essentially holds, thereby verifying the correctness of the dimensional analysis. Full article

To mitigate the negative impacts of traditional rigid revetments on river ecosystems, this study focuses on perforated plate grid revetments, aiming to reveal the hydrodynamic mechanisms and parameter collaborative optimization pathways that simultaneously achieve anti-scour stability and ecological water exchange. A series of flume scour tests were conducted, combined with high-resolution large eddy simulation (LES) validated by experimental data, to systematically analyze the regulatory effects of key design parameters—such as opening ratio and longitudinal offset angle—on near-bottom flow velocity attenuation, vortex structures, and water exchange efficiency. The results indicate that a prototype parameter combination of 0.25 m grid height and 0.50 m plate grid spacing can reduce local scour depth by about 30% and enhance vertical exchange through the synergy of jetting from the openings and internal vortices. The longitudinal offset of adjacent holes may enhance the transverse water exchange but may also significantly reduce the longitudinal exchange intensity; hence, further research is needed. A hole-to-baffle height ratio greater than 0.40 is identified as a critical threshold for improving exchange efficiency. This study proposes a collaborative design framework in which grid spacing controls scour safety and aperture parameters regulate exchange functions, providing an experimental basis for the precise design and performance enhancement of ecological revetments. Full article

To clarify the thermo-hydraulic performance and thermodynamic characteristics of rotational–perforated static mixer (RPSM) for laminar heat transfer enhancement in circular tubes, a three-dimensional steady laminar flow model was developed for inlet Reynolds numbers from 200 to 1000. The heat transfer enhancement, resistance increase, and irreversible losses of RPSM with two installation modes and Kenics were comparatively analyzed. The results show that RPSM (forward) exhibits the strongest practical heat transfer performance. Its convective heat transfer coefficient is on average 39.8% higher than that of Kenics, while its thermal effectiveness and number of transfer units are increased by 21.3% and 32.8%, respectively. However, the heat transfer enhancement of RPSM is accompanied by a significant increase in flow resistance. The Z-factors of RPSM (forward) and RPSM (backward) are approximately 3.4 and 6.2 times that of Kenics, respectively. Second law analysis shows that the Bejan numbers of all configurations are close to unity, indicating that total entropy generation is mainly dominated by heat transfer entropy generation. Although RPSM (forward) has a higher exergy destruction rate, its second law efficiency is on average 20.1% higher than that of Kenics. Flow–heat transfer coupling visualization shows that RPSM (forward) can maintain relatively continuous swirling and secondary flow structures, thereby promoting radial energy transport and temperature field uniformity. In contrast, RPSM (backward) induces stronger local recirculation and pressure loss, resulting in higher pumping power demand. Overall, for the specific RPSM geometry and Reynolds number range investigated in this study, RPSM (forward) shows advantages in heat transfer capacity and thermal exergy utilization, but these advantages are accompanied by a substantial flow resistance penalty. Therefore, further structural optimization should focus on retaining radial transport while reducing local pressure loss. Full article