Search Results (21)

The rupture of the contact wire (CW) of a railway overhead contact line (OCL or catenary) is expected to be a rare event. However, when it occurs, and a pantograph transits under the already broken section of the CW, this can have catastrophic consequences for the pantograph which in turn can cause a further extension of the damaged portion on the OCL with a consequent disruption in the service and cause there to be a long time before the operating condition can be restored. Therefore, the prevention of such events through effective catenary monitoring is gaining significant attention. The purpose of this work is to investigate the feasibility of a monitoring system that can be installed at each end of an OCL section which is able to detect the occurrence of a broken CW event, sending an alert to the management traffic system, so as to stop the train traffic before the damaged catenary is reached by other trains. A nonlinear dynamic analysis is employed to model the OCL’s response following a simulated CW rupture and identify a set of variables that can be measured at the line’s extremities related to the occurrence of breakage in the CW. Several locations of the rupture of a CW section along the line are simulated to investigate the influence on the time pattern of the measured variables and consequently on the extraction of a signature. Finally, a proposed measurement setup is presented, combining accelerometers and displacement transducers, instead of the direct measurement of the axial load of the OCL conductors. Full article

On 22 July 2020, an Mw 6.4 earthquake occurred in Nima County in the Qiangtang Terrane of the central Tibetan Plateau. This event, caused by normal faulting, remains controversial in terms of its rupture process and causative fault due to the complex tectonics of the region. In this study, we analyzed the coseismic and postseismic deformation using differential interferometric synthetic aperture radar (D-InSAR). The coseismic slip distribution was independently estimated through InSAR inversion and teleseismic waveform analysis, while the afterslip distribution was inferred from postseismic deformation. Coulomb stress failure analysis was conducted to assess the potential seismic hazard. Our results showed a maximum line-of-sight (LOS) coseismic deformation of about 29 cm away from the satellite, with quasi-vertical subsidence peaking at 35 cm. Four distinct deformation zones were observed in the quasi-east–west direction. Coseismic deformation and slip models based on InSAR and teleseismic data indicate that the Nima earthquake ruptured the West Yibu Chaka fault. The seismogenic fault had a strike of 26°, an eastward dip of 43°, and a rake of −87.28°, with rupture patches at depths of 3–13 km and a maximum slip of 1.1 m. Postseismic deformation showed cumulative LOS displacement of up to 0.05 m. Afterslip was concentrated in the up-dip and down-dip areas of the coseismic rupture zone, reaching a maximum of 0.11 m. Afterslip was also observed along the East Yibu Caka fault. Coulomb stress modeling indicates an increased seismic risk between the Yibu Caka fault and the Jiangai Zangbu fault, highlighting the vulnerability of the region to future seismic activity. Full article

Background: Rupture of the ACL is a common injury among men and women athletes. While planning the surgical ACL reconstruction procedure, the eventual graft’s diameter is extremely important. Many parameters are therefore evaluated pre-surgery to ensure access to reliable data for estimating the graft diameter. Considering this, magnetic resonance imaging (MRI), particularly qualitative analyses of the hamstring tendons, offers a promising approach. Methods: In a retrospective analysis, we carried out 3D segmentation of the gracilis (GT) and semitendinosus tendon (ST) utilizing MRI with varying slice thicknesses and field strengths. The cross-sectional area (CSA) was calculated on different levels (by relying on the models we had thus created) to generate a mean of CSA with six specific segments. We then correlated the mean CSA with the diameter of the graft measured during surgery. Results: A total of 32 patients were included (12 female, 20 male) in this retrospective analysis. We observed the largest CSA in segment 10 mm–0 (16.8 ± 6.1) with differences between men and women. The graft size and tendon diameter correlated significantly in all segments throughout our study cohort. The strongest correlation was apparent in the segment 10 mm–0 (r = 0.552). Conclusions: MRI-based 3D segmentation and the STGT CSA represent a reliable method for estimating preoperatively a quadrupled hamstring graft diameter. The 10 mm–0 mm segment above the joint line showed a strong correlation, making it an ideal reference for graft planning. Full article

On 7 January 2025, at Beijing time, an M_w7.1 earthquake occurred in Dingri County, Shigatse, Tibet. To accurately determine the fault that caused this earthquake and understand the source mechanism, this study utilized Differential Interferometric Synthetic Aperture Radar (DInSAR) technology to process Sentinel-A data, obtaining the line-of-sight (LOS) co-seismic deformation field for this earthquake. This deformation field was used as constraint data to invert the geometric parameters and slip distribution of the fault. The co-seismic deformation field indicates that the main characteristics of the earthquake-affected area are vertical deformation and east-west extension, with maximum deformation amounts of 1.6 m and 1.0 m for the ascending and descending tracks, respectively. A Bayesian method based on sequential Monte Carlo sampling was employed to invert the position and geometric parameters of the fault, and on this basis, the slip distribution was inverted using the steepest descent method. The inversion results show that the fault has a strike of 189.2°, a dip angle of 40.6°, and is classified as a westward-dipping normal fault, with a rupture length of 20 km, a maximum slip of approximately 4.6 m, and an average slip angle of about −82.81°. This indicates that the earthquake predominantly involved normal faulting with a small amount of left–lateral strike–slip, corresponding to a moment magnitude of M_w7.1, suggesting that the fault responsible for the earthquake was the northern segment of the DMCF (Deng Me Cuo Fault). The slip distribution results obtained from the finite fault model inversion show that this earthquake led to a significant increase in Coulomb stress at both ends of the fault and in the northeastern–southwestern region, with stress loading far exceeding the earthquake triggering threshold of 0.03 MPa. Through analysis, we believe that this Dingri earthquake occurred at the intersection of a “Y”-shaped structural feature where stress concentration is likely, which may be a primary reason for the frequent occurrence of moderate to strong earthquakes in this area. Full article

Background/Objectives: Secure large-bore cannula insertion is critical for effective extracorporeal membrane oxygenation (ECMO), as inadequate fixation can lead to complications such as infection, dislodgment, and life-threatening events. With inconsistent guidelines for ECMO line management, this study compares the effectiveness of traditional suture fixation to an adhesive securement method in the prevention of ECMO cannula dislodgment using an in vitro model. Methods: Porcine skin and muscle tissue sections were prepared and mounted in a custom holder. A 21F venous ECMO cannula was inserted using a modified Seldinger technique. Three fixation methods were randomly compared: (1) three silk sutures, and (2a) one silk suture with a CathGrip adhesive anchoring device. In addition, a sub-analysis was performed using (2b) the Hollister adhesive anchoring device. A uniaxial testing machine simulated 50 mm cannula dislodgment, measuring tensile forces at 12.5, 25, and 50 mm dislodgment points. Results: A total of 26 ECMO cannula fixations using sutures, 26 with adhesive CathGrip, six with a Hollister device, and three controls were tested across six porcine samples. Sutures demonstrated greater variability in force at maximum dislocation, with 27% rupturing at 50 mm. In contrast, CathGrip provided greater flexibility without tearing. The adhesive exhibited higher stiffness (2.38 N/mm vs. 2.09 N/mm, p < 0.001) and dislodgment energy (0.034 J vs. 0.032 J, p = 0.002) in the 0–5 mm range, while sutures showed greater stiffness in the 5–50 mm range (1.42 N/mm vs. 1.18 N/mm, p < 0.001). At larger displacements (25 mm and 50 mm) and in total energy absorption, no statistically significant differences were observed (p = 0.57). In a sub-analysis, the six fixations using the Hollister device exhibited higher variability and significantly lower dislodgment forces at 25 mm (p = 0.033) and 50 mm (p = 0.004) compared to the CathGrip device. Conclusions: This study suggests that adhesive anchoring methods, such as CathGrip, may provide comparable or potentially superior fixation strength to sutures for ECMO cannula stabilization under controlled conditions. However, further research, including clinical trials, is necessary to confirm these findings, evaluate long-term performance, and explore the implications for dislodgment risk and infection prevention in clinical practice. Full article

The structural response of single-story timber houses subjected to the 27 February 2010 Chile tsunami is studied in San Juan Bautista, an island town located nearly 600 km westward from the earthquake’s rupture source, in the Pacific Ocean. The ASCE 7-22 energy grade line analysis (EGLA) is used to calculate flow depths and velocities as functions of the topography and recorded runup. To understand the structural response along the topography, reactions and displacements are computed at six positions every 50 m from the coastline. Houses are modeled using the Robot software, considering dead and live loads cases under the Load and Resistance Factor Design (LRFD) philosophy. The results show that houses located near the coastline experience severe displacements and collapse due to a combination of hydrodynamic forces, drag and buoyancy, which significantly reduces the efficiency of the foundations’ anchorage. Structures far from the coastline are less exposed to reduced velocities, resulting in decreased displacements, structural demand and a tendency to float. Finally, the methodology is validated by applying a nonlinear analysis of the structures subjected to tsunami loads at the different positions considered in this study. Despite their seismic resistance, lightweight timber houses are shown to not be suitable for areas prone to tsunamis. Tsunami-resilient design should therefore consider heavier and more rigid materials in flooding areas and the relocation of lightweight structures in safe zones. Full article

Objective: Acute aortic dissection is a rare but frequently fatal aortic catastrophe with high morbidity and mortality. Especially in pregnant patients, acute dissection is often misdiagnosed putting two lives on the line. Due to its scarcity, only case reports have been reported. The aim of this study is to analyze the time of aortic dissection during the course of pregnancy and the outcome of emergency surgery in pregnant women with and without hereditary connective tissue disorder. Methods: We retrospectively reviewed all acute aortic dissections (type A and B) who underwent emergency aortic surgery at our institution between 1994 and 2022 and identified 13 patients with acute aortic dissection during pregnancy or directly postpartum. Mann–Whitney U and Fisher’s exact tests were used for statistical analysis. Results: Of the 13 included patients, 5 had a genetic syndrome. These patients were significantly younger at the time of dissection and at an earlier stage of pregnancy (second trimester). Even though operative and in-house mortality was zero, we lost one patient on postoperative day 14 due to rupture of the aortic root after transfer to another hospital. Survival of neonates was 77% including two aborted pregnancies. Conclusions: Surgical treatment of acute aortic dissection during pregnancy can be performed with excellent operative mortality for the mothers and satisfying survival of their neonates. In patients with genetic syndrome, dissection occurs during the early second trimester, whereas non-syndromic patients experience acute dissection in the late third trimester. Long-term follow-up is essential for timely re-intervention, if needed. Full article

Objective: We aimed to analyse patient outcomes following open (OAR) or endovascular repair (EVAR) of an abdominal aortic aneurysm (AAA) in Finland and Sweden from 1998 to 2017. Both intact and ruptured AAAs (rAAAs) were included in the analysis. Methods: Patient-level data from national registries in Finland and Sweden were analysed, pairing operations for intact and ruptured AAA repair with mortality data (date of death). All-cause mortality was the primary endpoint. Anonymized patient data from both countries were pooled, comprising a total of 32,324 operations. Ruptured and intact AAAs were considered separately. In total, EVAR was performed on 9619 intact AAAs and 1470 rAAAs, while OAR was performed on 13,241 intact AAAs and 7994 rAAAs. The patient’s age, sex and the date of operation were obtained as demographic information. Cox regression and Kaplan–Meier analyses were used to evaluate long-term (10-year) survival after the treatment of AAA or rAAA with either modality. Kaplan–Meier analysis was performed in three different age groups (<65 years, 65–79 years and ≥80 years). Results: Considering all age groups together, the 1-, 3- and 10-year Kaplan–Meier survival rates after EVAR were 93.4%, 80.5% and 35.3%, respectively, for intact AAA repair and 67.2%, 55.9% and 22.2%, respectively, for rAAA repair. For OAR of intact AAAs, the 1-, 3- and 10-year Kaplan–Meier survival rates were 92.1%, 84.8% and 48.7%, respectively. The respective rates for OAR of rAAAs were 55.4%, 49.3% and 24.6%. In a Cox regression analysis, a more recent year of operation was associated with improved survival, and older age affected survival negatively for both intact and ruptured AAA repair. If patients survived the first 90 days after the operation, the survival after intact AAA repair was 13.5 years for those <65 years (general population: 18.0 years), and 7.3 years for those ≥80 years (general population: 7.9 years). After rAAA repair, the mean survival was 13.1 years for patients <65 years and 5.5 years for patients ≥80 years, respectively. Conclusions: The long-term survival of patients undergoing intact AAA treatment at the age of 80 or older is close to that of the general population, provided they survive the operation. Conversely, for patients younger than 65, the long-term survival is markedly worse. The long-term survival of AAA patients has improved over time. Open surgery is still a safe and effective option for young patients undergoing intact AAA repair. Our results support the ESVS guidelines recommendation of EVAR being the first-line treatment for patients with rAAA. Full article

Background and Objectives: Spontaneous colonic perforations (SCPs) in teenagers and young adults are extremely rare. Common underlying conditions, such as colonic tumors and diverticulitis, are absent at that age. The vascular type of Ehlers–Danlos Syndrome (vEDS) is one cause of SCP. Methods: A 23-year-old male presented with an acute abdomen. The abdominal CT showed pneumoperitoneum with a large amount of fluid in the pelvis and abdomen, indicating hollow viscus rupture. At the level of the sigmoid colon, a defect in the intestinal wall and gas bubbles were seen. Results: Exploratory laparotomy confirmed sigmoid colon perforation without underlying pathology. Loop sigmoid colostomy was performed. Revisional surgery was undertaken due to clinical deterioration and intra-abdominal free fluid with small-bowel distension and air-liquid levels on abdominal CT 6 days later. Ileal subserosal hematomas were found, and many had ruptured, leaving a “zebra” pattern with lines of residual hematomas on the borders of subserosal hematomas. Genetic analysis confirmed vEDS. Conclusions: SCP in young adults or teenagers, in the absence of colonic disease, with clinical manifestations of connective tissue disorders should trigger genetic investigations for vEDS. SCP with a known vEDS could be treated with total colectomy to prevent further SCPs in the remaining colon. If segmental resections are performed, further SCP should be immediately excluded with any significant abdominal pain. Full article

Compelling evidence has shown that geomagnetic disturbances in vertical intensity polarization before great earthquakes are promising precursors across diverse rupture conditions. However, the geomagnetic vertical intensity polarization method uses the spectrum of smooth signals, and the anomalous waveforms of seismic electromagnetic radiation, which are basically nonstationary, have not been adequately considered. By combining pulse amplitude analysis and an experimental study of the cumulative frequency of anomalies, we found that the pulse amplitudes before the 2022 Luding M6.8 earthquake show characteristics of multiple synchronous anomalies, with the highest (or higher) values occurring during the analyzed period. Similar synchronous anomalies were observed before the 2021 Yangbi M6.4 earthquake, the 2022 Lushan M6.1 earthquake and the 2022 Malcolm M6.0 earthquake, and these anomalies indicate migration from the periphery toward the epicenters over time. The synchronous changes are in line with the recognition of previous geomagnetic anomalies with characteristics of high values before an earthquake and gradual recovery after the earthquake. Our study suggests that the pulse amplitude is effective for extracting anomalies in geomagnetic vertical intensity polarization, especially in the presence of nonstationary signals when utilizing observations from multiple station arrays. Our findings highlight the importance of incorporating pulse amplitude analysis into earthquake prediction research on geomagnetic disturbances. Full article

Objective: In treatment of aneurysms (SAAs) and pseudoaneurysms (SAPs) of the splenic artery, endovascular coil embolization is the approach most commonly used as it is minimally invasive and safe. However, it carries a significant rate of primary failure (up to 30%) and might be complicated by splenic infarction. The use of stent grafts might represent a valuable alternative when specific anatomical criteria are respected. We report a comprehensive review on technical and clinical outcomes achieved in this setting. Methods: We performed a comprehensive review of the literature through the MedLine and Cochrane databases (from January 2000 to December 2023) on reported cases of stenting for SAAs and SAPs. Outcomes of interest were clinical and technical success and related complications. The durability of the procedure in the long-term was also investigated. Results: Eighteen papers were included in the analysis, totalling 41 patients (n = 20 male 48.8%, mean age 55.5, range 32–82 years; n = 31, 75.6% SAAs). Mean aneurysm diameter in non-ruptured cases was 35 mm (range 20–67 mm), and most lesions were detected at the proximal third of the splenic artery. Stent grafting was performed in an emergent setting in n = 10 (24.3%) cases, achieving immediate clinical and technical success rate in 90.2% (n = 37) of patients regardless of the type of stent-graft used. There were no procedure-related deaths, but one patient died in-hospital from septic shock and n = 2 (4.9%) patients experienced splenic infarction. At the last available follow-up, the complete exclusion of the aneurysm was confirmed in 87.8% of cases (n = 36/41), while no cases of aneurysm growing nor endoleak were reported. None of the patients required re-intervention during follow-up. Conclusions: When specific anatomical criteria are respected, endovascular repair of SAAs and SAAPs using stent grafts appears to be safe and effective, and seems to display a potential advantage in respect to simple coil embolization, preserving the patient from the risk of end-organ ischemia. Full article

The use of Type IV cylinders for gas storage is becoming more widespread in various sectors, especially in transportation, owing to the lightweight nature of this type of cylinder, which is composed of a polymeric liner that exerts a barrier effect and an outer composite material shell that primarily imparts mechanical strength. In this work, the failure analysis of an HDPE liner in a Type IV cylinder for high-pressure storage was carried out. The breakdown occurred during a cyclic pressure test at room temperature and manifested in the hemispherical head area, as cracks perpendicular to the liner pinch-off line. The failed sample was thoroughly investigated and its characteristics were compared with those of other liners at different stages of production of a Type IV cylinder (blow molding, curing of the composite material). An examination of the liner showed that no significant chemical and morphological changes occurred during the production cycle of a Type IV cylinder that could justify the liner rupture, and that the most likely cause of failure was a design-related fatigue phenomenon. Full article

Within the research project ITSAFE, two full-scale structures were built, one consisting of a single-storey, two-span, 7.00 × 14.00 m² RC frame with a solid slab and another consisting of a two-storey, 7.00 × 7.00 m² RC frame with solid slabs. In the two-span frame, one of the central supports was first demolished using a pneumatic hammer, resulting in rather limited damage (a 14–15 cm deflection at the removed support location). However, torsional cracks appeared at the interface between a column and slab in one of the outer supports. When the second central support was removed, the structure collapsed with the failure of the support–slab connection. The same type of cracking was observed in the two-storey structure, where the column removal was dynamic, and a 22 cm deflection was measured. These experimental results question current practice in which, for internal supports, alternative load path mobilizing membrane forces in the slab are said to prevent their collapse, or in the cases of edge and corner columns, rupture line analysis is used and suggests that special reinforcement at the column–support connection is also needed to prevent the premature failure of the structure. Full article

In this study, a collection of newly developed α-methylchalcone derivatives were synthesized and assessed for their inhibitory potential against human cervical cancer cell lines (HeLa, SiHa, and C33A) as well as normal human cervical epithelial cells (H8). Notably, compound 3k exhibited substantial inhibitory effects on both HeLa and HeLa/DDP cells while demonstrating lower toxicity toward H8 cells. Furthermore, the compound 3k was found to induce apoptosis in both HeLa and HeLa/DDP cells while also inhibiting the G2/M phase, resulting in a decrease in the invasion and migration capabilities of these cells. When administered alongside cisplatin, 3k demonstrated a significant reduction in the resistance of HeLa/DDP cells to cisplatin, as evidenced by a decrease in the resistance index (RI) value from 7.90 to 2.10. Initial investigations into the underlying mechanism revealed that 3k did not impact the expression of P-gp but instead facilitated the accumulation of rhodamine 123 in HeLa/DDP cells. The results obtained from CADD docking analysis demonstrated that 3k exhibits stable binding to microtubule proteins and P-gp targets, forming hydrogen bonding interaction forces. Immunofluorescence analysis further revealed that 3k effectively decreased the fluorescence intensity of α and β microtubules in HeLa and HeLa/DDP cells, resulting in disruptions in cell morphology, reduction in cell numbers, nucleus coagulation, and cell rupture. Additionally, Western blot analysis indicated that 3k significantly reduced the levels of polymerized α and β microtubule proteins in both HeLa and HeLa/DDP cell lines while concurrently increasing the expression of dissociated α and β microtubule proteins. The aforementioned findings indicate a potential correlation between the inhibitory effects of 3k on HeLa and HeLa/DDP cells and its ability to inhibit tubulin and P-gp. Full article

The carotid artery is a major blood vessel that supplies blood to the brain. Plaque buildup in the arteries can lead to cardiovascular diseases such as atherosclerosis, stroke, ruptured arteries, and even death. Both invasive and non-invasive methods are used to detect plaque buildup in the arteries, with ultrasound imaging being the first line of diagnosis. This paper presents a comprehensive review of the existing literature on ultrasound image analysis methods for detecting and characterizing plaque buildup in the carotid artery. The review includes an in-depth analysis of datasets; image segmentation techniques for the carotid artery plaque area, lumen area, and intima–media thickness (IMT); and plaque measurement, characterization, classification, and stenosis grading using deep learning and machine learning. Additionally, the paper provides an overview of the performance of these methods, including challenges in analysis, and future directions for research. Full article