Search Results (2,106)

Boerhaave syndrome (BS) and subsequent septic mediastinitis represent a complex cascade of events from esophageal perforation to septic shock. The pathophysiology involves chemical injury, polymicrobial contamination, cytokine storm, endothelial dysfunction, coagulation disorders, and ultimately multiple organ failure. Understanding these mechanisms is crucial for proper therapeutic management that can interrupt this lethal sequence. Due to the complexity of this condition, it is almost impossible to develop a feasible treatment protocol for every situation. The article, through a literature review, evaluates the pathophysiological mechanisms, the consequences of spontaneous esophageal rupture, as well as the therapeutic techniques available for these situations. These elements are the basis of the management of spontaneous esophageal rupture, which involves adapting and customizing the treatment for each patient. Full article

Introduction: Perforator-based fasciocutaneous flaps are particularly suitable for soft tissue reconstruction of the lower extremities. The most commonly used flap is the microvascular Anterior Lateral Thigh Flap (ALT). Pedicled propeller-type flaps are less frequently utilized due to higher complication rates. The aim of this study was to compare postoperative perfusion patterns of these fundamentally different flaps to increase their basic understanding. Methods: A retrospective data analysis was performed (2017–2022), including patients who underwent flap reconstruction of the lower extremity either with a perforator-based pedicled Propeller flap or free tissue transfer with an ALT flap. Only patients with documented postoperative perfusion monitoring of the flap using the laser Doppler spectrophotometry system (LDSP) were included. Demographic data, comorbidities and perioperative data as well as perfusion profiles given by the LDSP were analyzed. Results: Seven patients who received a propeller flap and 18 who received a free ALT were identified. Defects were most often due to trauma (Propeller flap n = 5; 71.1%; ALT n = 7; 38.9%) and chronic wounds (Propeller flap n = 1; 14.3%; ALT n = 5; 27.8%). The most common complication was prolonged wound healing (Propeller flap n = 3; 42.9%; ALT n = 8; 44.4%). In cases with postoperative surgical complications, a distinctly delayed recovery in perfusion of propeller flaps was seen during the first 72 h after surgery. Conclusions: Propeller and ALT flaps exhibit distinct perfusion patterns, with Propeller flaps showing a congestion-prone profile (elevated rHB, delayed hyperperfusion) and ALT flaps an inflow-dependent, ischemia-driven profile (lower rHB and SO₂). Full article

Thermal bridging through cold-formed steel (CFS) studs significantly reduces the thermal performance of light gauge steel frame (LSF) wall systems, particularly in climates demanding higher thermal resistance (R-value). While thermal breaks are commonly used, they increase material costs and construction complexity. According to NCC 2022, the minimum total R-value requirement for external walls ranges between 2.8 and 3.8 m²·K/W depending on the climate zone and building class. This study therefore evaluated web-perforated steel studs as a passive strategy to enhance thermal resistance of LSF walls, analysing 120 configurations with validated 3D finite element models in Abaqus and benchmarking in THERM. The results showed that web perforations consistently improved R-values by 14 to 20%, as isotherm contours and heat flux vectors demonstrated disruption of direct heat flow through the stud, thereby mitigating thermal bridging. Although the axial compression capacity of web-perforated CFS studs decreased by 29.5%, the use of 4 mm hole-edge stiffeners restored 96.8% of the original capacity. The modified NZS 4214:2006 and ASHRAE Modified Zone methods, incorporating steel area reduction and heat flux redistribution, closely matched Abaqus predictions, with coefficients of variation (COV) below 0.009, corresponding to less than 1% relative deviation between analytical and numerical R-values. Furthermore, application of web-perforated CFS studs in five external wall systems demonstrated improved thermal resistance, ensuring compliance with NCC 2022 R-value requirements across all Australian climate zones. Overall, the findings establish web-perforated studs as an effective solution for improving the energy performance of LSF building envelopes. Full article

Background: Non-islet cell tumor hypoglycemia is increasingly reported with gastrointestinal stromal tumors (GIST), but population-level estimates of its clinical impact are limited. We evaluated associations between hypoglycemia and inpatient outcomes among GIST hospitalizations. Methods: We conducted a retrospective cross-sectional study of the National Inpatient Sample (NIS) 2018–2020. Adult GIST discharges were identified by ICD-10-CM codes and stratified by hypoglycemia. Primary outcomes were in-hospital mortality and resource utilization—length of stay (LOS) and total hospital charge. Secondary outcomes included malnutrition, sepsis, ascites, peritonitis, bowel perforation, intestinal obstruction, gastrointestinal bleeding, and iron deficiency anemia. Analyses used survey-weighted logistic regression for binary outcomes and generalized linear models for continuous outcomes. A propensity score-matched sensitivity analysis balanced sepsis and malnutrition. Results: Among 61,725 GIST hospitalizations, 0.72% had hypoglycemia. Mortality was 12.6% with hypoglycemia vs. 3.1% without; adjusted odds of death were higher (aOR 4.16, 95% CI 2.06–8.37; p < 0.001). Hypoglycemia was also associated with malnutrition (aOR 5.63, 3.37–9.40), sepsis (aOR 4.00, 2.24–7.14), ascites (aOR 3.43, 1.63–7.19), and peritonitis (aOR 2.91, 1.17–7.22). LOS was 4.61 days longer on average (not significant; p = 0.185), and total hospital charge was $5218 higher (β = 19,116.8; p = 0.95). In the matched cohort, the mortality association attenuated but persisted (aOR 1.38, 1.27–1.49; p < 0.001); peritonitis remained significant (aOR 1.10, 1.04–1.17), intestinal obstruction (aOR 4.91, 3.44–7.05) and iron deficiency anemia (aOR 3.54, 1.62–7.74) became significant, while ascites and gastrointestinal bleeding were not significant. Conclusions: Hypoglycemia in GIST, although uncommon, marks a higher-risk inpatient trajectory with increased mortality and several complications; these signals largely persist after balancing severity proxies. Resource-use differences were directionally higher but not statistically significant. Recognition of hypoglycemia may aid risk stratification and inpatient management in GIST. Full article

Laser trepan drilling and laser helical drilling are typical methods for fabrication of micro through-holes through scanning laser beam. In the drilling process, the subsequent laser pulse may be occluded by the edge and the sputter deposition at the edge of the previous drilled trench. Dynamic focus feeding and widening path can be employed to lessen the occlusion effect and both of them are always employed in laser helical drilling. However, Widening the trench needs to remove more volume of material and may bring certain negative effects such as lowering the recoil pressure as well as less splashing melt due to the limited constraint of trench wall. The effects of dynamic feeding the focal plane and widening the scanning path on the quality and efficiency in the nanosecond laser drilling process were investigated through laser drilling holes with diameter of 500 μm on a 300 μm thick GH4169 plate. Results show that dynamic focus feeding is beneficial in both drilling efficiency and drilling quality. Through laser helical drilling with dynamic focus feeding, micro through-hole can be fabricated in 5 s, and both smaller tilting angle of 0.073 rad and smaller heat-affected zone of 0.63 mm in radius can be obtained. Widening scanning path is helpful to perforating rapidly but leads to much more recast layer coating. the quality of the micro through-holes depends not only on the utilization efficiency of the laser energy, but also on high temperature spatter deposition, which is the source of the difference between different drilling strategies. Due to the low cost in equipment and the better hole quality, the laser drilling, especially laser helical drilling, has potential applications ranging from aerospace fields to normal fields such as the agricultural machinery industry. Full article

This study investigates the influence of two processing methods, namely wet and dry, on the structural, physical, mechanical, and acoustic performance of green lignocellulosic fiber-based composite panels. A comprehensive evaluation was carried out to compare the vertical density profile, affinity to water, thermal insulation and sound absorption, microstructural features, and mechanical performance of two types of experimental panels. The dry-processed samples exhibited 24% more prominent vertical density profile and superior dimensional stability, with lower thickness swelling (TS) and water absorption (WA) due to their more compact fiber arrangement compared to those of the specimens made using the wet process. However, the wet-processed panel demonstrated significantly enhanced mechanical properties, including 36% higher modulus of elasticity (MOE), 61% modulus of rupture (MOR), and 67% internal bonding strength (IB). Such findings could be attributed to their increased fibrillation and improved inter-fiber bonding compared with those of the panels made using the dry process. The thermal conductivity values of the wet- and dry-processed panels were found to be 0.053 W/mK and 0.057 W/mK, respectively. Acoustic analysis of the samples revealed that while the dry-processed panel slightly outperformed in terms of low-frequency sound absorption, the wet-processed panel exhibited superior high-frequency absorption, particularly when perforations were introduced. Microscopic examination of the samples confirmed that wet processing produced a more homogenous and fibrillated microstructure, correlating well with the observed enhancements in mechanical and acoustic performance. In conclusion, it can be stated that the processing strategies of such panels could be applied for diverse engineering applications, including thermal insulation, acoustic damping, and sustainable structural materials. Full article

Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. The COVID-19 pandemic disrupted healthcare systems globally, raising concerns about delays in CRC diagnosis and treatment, and their potential negative effects on surgical outcomes. However, the extent of this impact remains uncertain. Aim: To compare the clinical characteristics, treatment strategies, and outcomes of CRC patients between the Pre-COVID-19 and COVID-19 Era groups, and to identify independent predictors of metastasis and mortality. Methods: This retrospective multicenter study included 397 CRC patients who underwent surgical treatment between 1 July 2018, and 1 August 2021, at three tertiary medical centers. Patients were divided into two groups: Pre-COVID-19 (n = 213) and COVID-19 Era (n = 184). Demographic data, tumor characteristics, surgical approach, postoperative complications, and survival outcomes were analyzed. Logistic regression analysis was conducted to identify independent predictors of metastasis and mortality. Results: The median age was 64 years (95% CI: 63–66), with 59.2% being male. Compared to the Pre-COVID-19 group, patients in the COVID-19 Era had significantly larger tumors (p < 0.001), with a significantly higher total LN retrieved (p = 0.006), more advanced T-stage (p = 0.007), higher N2 lymph node involvement (p = 0.027), and poorer tumor differentiation (p = 0.030). Intestinal perforation was more frequent in the Pre-COVID-19 group (p = 0.042). Multivariate analysis revealed increased odds of mortality associated with the positive LN retrieved (OR: 1.14; p = 0.001), moderate tumor differentiation (OR: 2.99; p = 0.043), poor differentiation (OR: 4.57; p = 0.023), undifferentiated histology (OR: 6.95; p = 0.028), intestinal obstruction (OR: 2.67; p = 0.007), intestinal perforation (OR: 11.76; p < 0.001), and distant metastasis (OR: 2.86; p = 0.008). Regarding metastasis, elevated preoperative CEA (OR: 1.02; p = 0.002), lymph node involvement (OR: 4.87; p = 0.002), and perineural invasion (OR: 2.17; p = 0.033) were independently associated with increased odds of metastasis. Conclusions: Although overall survival did not differ significantly between groups, patients treated during the COVID-19 Era exhibited more advanced histopathological characteristics, including a higher proportion of T4 tumors, increased N2 lymph node involvement, and poorer differentiation grades. Despite no significant differences in postoperative complications between groups, it is noteworthy that preoperative intestinal perforation was less frequent in the COVID-19 Era cohort. Full article

Mandibular reconstruction with the fibula free flap is the gold standard for large defects, with virtual surgical planning becoming integral to the process. The localization and dissection of critical vessels, such as the recipient vessels in the neck and the perforating vessels of the fibula flap, are demanding steps that directly impact surgical success. Augmented reality (AR) offers a solution by overlaying three-dimensional virtual models directly onto the surgeon’s view of the operative field. We report the first case in Latin America utilizing a low-cost, commercially available holographic navigation system for complex microsurgical mandibular reconstruction. A 26-year-old female presented with a large, destructive osteoblastoma of the left mandible, requiring wide resection and reconstruction. Preoperative surgical planning was conducted using DICOM data from the patient’s CT scans to generate 3D holographic models with the Medicalholodeck^® software. Intraoperatively, the primary surgeon used the AR system to superimpose the holographic models onto the patient. The system provided real-time, immersive guidance for identifying the facial artery, which was anatomically displaced by the tumor mass, as well as for localizing the peroneal artery perforators for donor flap harvest. A free fibula flap was harvested and transferred. During the early postoperative course and after 3-months of follow-up, the patient presented with an absence of any clinical complications. This case demonstrates the successful application and feasibility of using a low-cost, consumer-grade holographic navigation system. Full article

Extreme weather events, such as typhoons, induce strong wave–current interactions that significantly alter nearshore hydrodynamic conditions, particularly in shallow intertidal zones. This study investigates the influence of wind speed and water depth on wave–current coupling under typhoon conditions in Shenhu Bay, southeastern China—a semi-enclosed bay that hosts multiple ancient forest relics within its intertidal zone. A two-tier numerical modeling framework was developed, comprising a regional-scale hydrodynamic model and a localized high-resolution model centered on a protective structure. Validation data were obtained from in situ field observations. Three structural scenarios were tested: fully intact, bottom-blocked, and damaged. Results indicate that wave-induced radiation stress plays a dominant role in enhancing flow velocities when wind speeds exceed 6 m/s, with wave contributions approaching 100% across all water depths. However, the linear relationship between water depth and wave contribution observed under non-typhoon conditions breaks down under typhoon forcing. A critical depth range was identified, within which wave contribution peaked before declining with further increases in depth—highlighting its potential sensitivity to storm energy. Moreover, structural simulations revealed that bottom-blocked devices, although seemingly more enclosed, may be vulnerable to vertical pressure loading due to insufficient water exchange. In contrast, perforated designs facilitate an internal–external hydrodynamic balance, thereby enhancing protective effect. This study provides both theoretical and practical insights into intertidal structure design and paleo-heritage conservation under extreme hydrodynamic stress. Full article

Background/Objectives: This study aimed to investigate the association between the position of impacted mandibular third molars and the morphology of the lingual cortical bone using cone beam computed tomography (CBCT), and to determine how impaction depth and angulation influence the risk of lingual cortical perforation. Methods: CBCT scans of 120 impacted mandibular third molars from 71 adult patients were retrospectively evaluated. Teeth were classified based on Pell & Gregory’s and Winter’s classifications. Lingual cortical morphology was categorized as undercut, parallel, slanted, or round. The relationship between the root apex and the lingual plate was classified as non-contact, contact, or perforating. Linear measurements included cortical lingual bone thickness and the distance from the apex to the outer surface of the lingual cortex. Results: Lingual bone morphology showed significant associations with both impaction depth and angulation, with parallel morphology more common in deeper and more angulated impactions. Lingual cortical perforation was observed in approximately 30% of the teeth, predominantly at the apex, with horizontal and deeply impacted molars (Class II, Level C) representing the highest-risk configurations. Although cortical thickness and apex-to-cortex distance were significantly smaller in apically perforated cases, no definitive threshold could be established, and these parameters were insufficient as standalone predictors at the cementoenamel junction or mid-root levels. Conclusions: Tooth angulation and impaction depth are significant predictors of lingual bone morphology and perforation risk. CBCT imaging is therefore recommended beyond low-risk cases (Level A, Class I, vertical) to improve preoperative planning, strengthen informed consent, and guide surgical strategies aimed at minimizing complications and enhancing patient safety. Full article

Appropriate accelerated deterioration methods are crucial for studying the deterioration behavior of reinforced concrete linings in subsea tunnels. To investigate the deterioration mechanisms of reinforced concrete (RC) structures in marine environments, this study employed the electromigration method to simulate accelerated chloride-induced corrosion of steel reinforcement. The results demonstrate that under a direct current (DC) electric field, chloride ions migrate directionally and accumulate on the side of the steel facing the chloride source, successfully inducing non-uniform corrosion features that closely resemble those in natural environments. The side facing chloride ingress exhibited severe corrosion and significant cross-sectional loss, while the shielded side remained largely intact. The experimental process clearly reveals that the applied electric field does not directly initiate corrosion of the steel reinforcement before chloride ions migrate to its surface. Furthermore, analysis of experimental parameters showed that symmetrical perforations on electrode plates are crucial for a uniform electric field, while perforation ratio and electrode–specimen distance have a minor influence. The average chloride penetration depths corresponding to electrode plate perforation areas of 5.5%, 15%, 25.5%, and 38.1% were measured as 1.63 cm, 1.67 cm, 1.57 cm, and 1.57 cm, respectively. This research confirms electromigration as an efficient and reliable technique for accelerated corrosion testing, providing a significant theoretical basis for assessing and predicting the long-term durability of marine engineering structures. Full article

The study of explosion loadings in cabin structures is of great significance for evaluating structural damage. At present, most studies focus on the characteristics of explosion loadings in a single cabin. However, there are few studies on the loading characteristics of adjacent cabins under multi-cabin explosions, and there is no calculation model for calculating the load of adjacent cabins. In order to study the pressure loading characteristics of the adjacent cabin during an internal explosion, a simplified calculation model of the adjacent cabin load was constructed. The adjacent cabin environment was constructed by clamping the perforated baffle between the two cabins. The opening area of the perforated baffle accounts for 3%, 5%, 15%, and 20% of the area of the baffle. The pressure loadings of the adjacent cabin were measured by an implosion test in the adjacent cabin. A finite element simulation calculation was carried out for the test conditions. The results show that the rise time of the quasi-static pressure is in good agreement with the test results. Based on the above research, the pressure loading characteristics of the adjacent cabin were determined. A simplified model of pressure change during the pressure relief process from the explosion cabin to the adjacent cabin was obtained. Assuming an exponential decay process during pressure venting, a theoretical method for calculating the rise time of quasi-static pressure in adjacent cabins was derived. Compared with the experimental value, the maximum error is 15.9%, which can realize the prediction of the quasi-static pressure rise time of the adjacent cabin during the internal explosion. This calculation method can provide load input for internal explosion damage assessment of the complex structure of the multi-cabin. Full article

Acute appendicitis is a common cause of acute abdominal pain but is rare in infants because of anatomical and physiological characteristics that reduce the risk of the luminal obstruction of the appendix. However, when it occurs in infants, it is often difficult to diagnose clinically and may progress rapidly to a fatal outcome. We report a forensic autopsy case of an 11-month-old infant who died 2 d after developing fever and decreased oral intake, without antemortem diagnosis. Autopsy revealed fibrinous ascitic fluid and an edematous, dark-red appendix with fibrin deposits, but no macroscopic luminal obstruction or perforation. Histopathological examination showed diffuse inflammatory cell infiltration and hemorrhage across all layers of the middle and peripheral portions of the appendix, along with lymphoid hyperplasia in the middle portion. Intestinal bacteria were detected in the ascitic fluid. The cause of death was identified as acute appendicitis with subsequent generalized peritonitis. Although luminal obstruction is a common cause of appendicitis, it was not observed macroscopically in this case. However, histopathological findings suggested that lymphoid hyperplasia in the middle portion of the appendix caused luminal narrowing and impaired circulation in the appendiceal wall, triggering appendicitis. This case demonstrates that infantile appendicitis can be fatal even without perforation and highlights the potential role of lymphoid hyperplasia in the pathogenesis. It also underscores the importance of considering appendicitis in the differential diagnosis of infants with nonspecific symptoms and illustrates the value of postmortem histopathological investigation in elucidating the disease mechanism. Full article

Hydraulic fracturing technology is crucial for promoting oil and gas resource development. In recent years, water hammer fracture diagnostic techniques, derived from the water hammer effect in hydraulic fracturing, have garnered significant attention due to their low cost and ease of operation. The characteristic parameters of water hammer pressure are closely related to fracture geometry parameters. Monitoring the characteristics of water hammer pressure at the wellhead allows for rapid assessment of fracturing effectiveness. This study comprehensively considers wellbore friction, perforation friction, and the fluid loss effect within hydraulic fractures, establishing a mathematical model for the evolution of water hammer pressure during multi-cluster staged fracturing in horizontal wells. Based on field-monitored water hammer data from multiple stages, this study employed water hammer fracture diagnostics to inversely determine the geometric parameters of fractures in different fracturing stages. Characteristic parameters of the water hammer pressure, including the initial amplitude, number of oscillations, oscillation duration, and attenuation rate, were calculated for different well sections. Furthermore, the correlations between these water hammer characteristics and the fracture geometric parameters were analyzed. The correlation analysis between characteristic parameters of water hammer pressure and geometric parameters of hydraulic fractures indicates that under conditions of longer fracture half-length and smaller fracture height, the generated water hammer pressure exhibits a higher initial amplitude, fewer oscillations, a shorter oscillation duration, and a larger attenuation rate. The research findings can facilitate rapid estimation of fracture geometry using water hammer pressure, thereby optimizing fracturing design and enhancing fracturing effectiveness. Full article

This study examines the characteristic parameters required for non-circular-hole microperforated panels (MPPs) to achieve sound absorption performance comparable to that of conventional circular-hole MPPs. Through numerical analysis, the flow resistivity and perforation ratio were found to be key parameters influencing the absorption characteristics of MPPs with square and equilateral triangular holes. The results indicate that for square-hole MPPs, matching either the flow resistivity alone or both the flow resistivity and perforation ratio to those of circular-hole MPPs leads to similar sound absorption characteristics. In contrast, for equilateral triangular-hole MPPs, both the above parameters must be matched to ensure comparable performance. Furthermore, this study explores MPPs incorporating a combination of circular and non-circular holes. It was confirmed that by appropriately matching the flow resistivity and perforation ratio, such mixed-hole MPPs can achieve sound absorption characteristics similar to those of MPPs composed solely of circular holes. These findings contribute to the broader design possibilities of MPPs, providing a foundation for optimising hole geometries in practical applications where manufacturing constraints or aesthetic considerations may necessitate non-circular hole patterns. Full article