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High-strain-rate fracture behavior of rock-like materials : Insights from Split Hopkinson Pressure Bar testing and dynamic phase-field modeling
No full textThis study integrates a hydrostatic–spectral–deviatoric decomposition within a dynamic phase-field finite element framework to assess its effectiveness in simulating fracture patterns in brittle materials subjected to high strain-rate compressive loading. The investigation focuses on Split Hopkinson Pressure Bar (SHPB) experiments using gypsum plaster specimens with central holes, tested in a synchronously assembled setup. The hydrostatic–spectral–deviatoric decomposition enables a distinction between tensile and compressive strain energy components to accurately model dynamic fracture processes in quasi-brittle materials under compressive and mixed-mode loading, where traditional formulations often fall short. To maintain consistency, the numerical simulations were calibrated using material parameters previously identified through quasi-static tests on the same material and different geometries. The simulated results closely mirrored experimental observations, successfully reproducing key features such as crack paths, propagation sequence, timing, boundary motion, and crack tip velocity. This enhanced modeling approach offers valuable insight into dynamic fracture behavior in brittle systems and underscores its potential for improving predictive capabilities under high strain-rate loading scenarios
Near infrared spectroscopy versus stump pressure in detecting cerebral ischemia during carotid endarterectomy : a prospective multicenter observational study
No full textBackground: Determining the need for shunt use during carotid endarterectomy (CEA) under general anesthesia (GA) can be based on different methods, and one of the most common is stump pressure (SP). Previous studies have found favorable results of near infrared spectroscopy (NIRS). Methods: Patients undergoing CEA in 2 swedish hospitals were prospectively included. SP, rSO2 at different timepoints as well as neurological symptoms during surgery were reported for all patients. Receiver operating curve (ROC) analysis was used to determine the optimal cutoff points for SP and rSO2. Results: A total of 293 patients underwent CEA under local anesthesia (LA) and 66 under GA in 2 hospitals. Thirty two patients operated under LA had neurological symptoms. A relative change in ipsilateral rSO2 ≤ −9% had a negative predictive value (NPV) of 99% in detecting neurological symptoms during clamping. Patients who developed neurological symptoms during clamping had lower ΔrSO2 (−14% ± 6% vs. −4 ± 5%, P < 0.001) and lower SP (36 ± 21 mm Hg vs. 56 ± 19 mm Hg, P < 0.001) compared to those who did not. A ΔrSO2 of ≤ −9% had a sensitivity of 91% (95% confidence interval (CI): 75–98%) and a specificity of 82% (95% CI: 77–87%) in predicting cerebral ischemia, whereas a SP < 50 mm Hg had a sensitivity of 78% (95% CI: 58–91%) and a specificity of 60% (95% CI: 54–67%). Conclusion: This study found that NIRS could reduce unnecessary shunting while still having a higher sensitivity compared to SP. Additionally, it can also monitor shunt patency
Sonolytic and ultrasound-assisted hydrogen production: insights, trends, and future perspectives
No full textThis study employs the bibliometric review method to assess the evolution of research in sonolytic and ultrasound-assisted hydrogen production between 2000 and 2025 using data from the Scopus database. The study found research done so far as a dynamic, cross-disciplinary field driven by global decarbonization and technological innovation. Keyword and thematic mapping identified a central focus towards maximizing the hydrogen evolution reaction (HER) with the assistance of ultrasound catalysis, with advanced materials like g-C3N4, TiO2, and quantum dots. Emerging themes of piezocatalysis, biohydrogen, and ultrasonication-enhanced pretreatment indicate a trend towards multifunctional, sustainable, and bio-integrated processes. The clustering analysis identified distinct strategic research directions, including visible-light-driven heterojunctions, anticorrosion electrodes, ultrasonic fermentation, and hybrid catalytic systems integrating sonochemistry with photocatalysis, electrocatalysis, and thermochemical reforming. Non-noble metal catalysts and nanostructures enabled by sonication are especially gaining prominence owing to their efficiency and scalability. The country-level analysis revealed a commanding position for China, with growing contributions from India, South Korea, and strategic international collaborations. Together, the field is transitioning from fundamental research to application-oriented innovation, and the future opportunity rests in scalable, hybrid systems that integrate ultrasonic, optical, and biochemical processes. These findings suggest that ultrasound-assisted hydrogen generation may contribute to advances in sustainable energy technologies and potential industrial implementation
Development of the N400 in infancy
No full textIn this longitudinal EEG study, we examined the developmental trajectory of the N400 component using a wordpicture mismatch-paradigm in 18 infants at 10 and 12 months of age. Event-related potentials (ERPs) were recorded and analyzed in three consecutive time windows (400-600 ms, 600-800 ms, 800-1000 ms poststimulus). At 10 months, a significant N400-like effect occurred (400-600 ms) but diminished by 12 months, potentially due to developmental changes or increased stimuli familiarity. No significant correlation emerged between N400 amplitude and parental reports of receptive vocabulary. These results imply that the N400 effect is present already in infancy
Year-round variation in bryophyte-associated nitrogen fixation in the Arctic
No full textIn northern biomes, growth is nitrogen (N) limited, but bryophytes are abundant. These bryophytes often host N2-fixing microorganisms (diazotrophs) that play a crucial role in the N cycle of these ecosystems. Despite their importance, how the bryophyte-associated N2-fixation varies across species and seasons (summer, autumn, winter, and spring) remains poorly understood. We measured N2-fixation rates for 10 bryophyte species in situ throughout the entire year in the Arctic with additional incubations to verify the method. We measured positive N2-fixation during most of the year, except for the coldest period (February). The species growing in the wettest conditions (Sphagnum spp.) had the highest N2-fixation rates in summer, while bryophytes in drier conditions peaked in N2-fixation rates in spring and autumn. The seasonal variation in N2-fixation activity was pronounced, but similar patterns were found among different species. This study reveals that bryophyte-associated N2-fixation in northern ecosystems is larger than previously assumed, as it occurs over a more extended part of the year than previously inferred. Furthermore, the importance of bryophyte-associated diazotrophs cannot be quantified without considering both the diversity of bryophytes and their variation in N2-fixing seasonal activity patterns. Both future changes in climatic conditions and biodiversity of bryophytes can thus have large implications for the N cycle in arctic regions
Efficient finite difference modeling of infrasound propagation in realistic 3D domains : Validation with wind turbine measurements
No full textWe present a high-fidelity simulation tool for accurate acoustic modeling across a wide range of applications. The numerical method is based on diagonal-norm Summation-By-Parts (SBP) finite-difference operators, which guarantee linear stability on piecewise curvilinear multi-block grids. Realistic three-dimensional atmospheric and topographic data are directly incorporated into the simulations, and the solver is implemented in CUDA to achieve high computational efficiency. Verification is performed through convergence studies against highly resolved benchmark problems in both two and three spatial dimensions, while validation is carried out using high-quality infrasound measurements from two modern wind farms in Sweden. The results show that modern, large-scale wind turbines generate infrasound levels significantly higher than those reported for older, smaller turbines. These findings advance the understanding of the acoustic characteristics of contemporary wind turbines and provide important guidance for assessing their potential environmental and societal impacts
Change in cardiac troponin T to differentiate acute from chronic myocardial injury in the Emergency Department.
No full textINTRODUCTION: Persistently elevated cardiac troponin (cTn) values are observed in many patients with suspected acute coronary syndrome (ACS) in the absence of myocardial infarction and may reflect underlying cardiac disease. Chronic myocardial injury is defined where cTn values are elevated and vary by ≤ 20 % on sequential measurements. We aimed to evaluate whether these criteria are reliable over short intervals applied in accelerated diagnostic pathways. METHODS: In a secondary analysis of a prospective, multi-centre cohort study of patients with suspected ACS, cTnT was measured at presentation, 1, 2 and 6-36 h, and the final diagnosis adjudicated according to the Fourth Universal Definition of Myocardial Infarction. Two criteria for chronic myocardial injury were compared: a relative change in cTn of ≤ 20 % and an absolute change < 3 ng/L, and the findings externally validated. RESULTS: At presentation cTnT was elevated in 242 of 1,000 (25 %) patients (73 years, 42 % female), of whom 94/242 (39 %), 13/242 (5 %) and 137/242 (56 %) had myocardial infarction, acute or chronic myocardial injury, respectively. A relative change of ≤ 20 % misclassified 58 % (59/101) and 49 % (48/98) of patients with a final diagnosis of acute myocardial injury or infarction at 1 and 2 h, respectively, whereas an absolute change of < 3 ng/L misclassified 22 % (22/101) and 15 % (15/98). In the validation cohort (n = 621), the relative and absolute change criteria at one hour misclassified 43 % (13/30) and 17 % (5/30) of those with myocardial infarction. CONCLUSIONS: Chronic myocardial injury cannot reliably be differentiated from acute myocardial injury or infarction by recommended criteria over short remeasurement intervals in the Emergency Department. Longer intervals between sampling and absolute rather than relative criteria may reduce the risk of misclassification
Improvement of S-shaped instability and power performance of a reversible pump-turbine runner
No full textThe reversible pump turbine (RPT) is likely to enter the S-characteristic zone, thereby inducing pressure fluctuations and oscillations to the grid connection. An innovative optimization framework of RPT runner is presented to mitigate the detrimental flow conditions associated with the S-curve under turbine mode. Comprehensive runner geometric parameters were considered with the optimal Latin hypercube (OLH) sampling technique to generate different designs. Computational fluid dynamics (CFD) was adopted to characterize the RPT hydraulic efficiency and unstable S-characteristics curve, in which the position of the second inflection point was innovatively selected as the objective function. The CFD-driven surrogate-based design methodology was achieved by artificial neural network (ANN). The multi-objective optimization evolutionary algorithm guided the search for the optimal runner configuration with high efficiency and improved S-characteristics. The vortices in the runner channels and high-speed water ring in the vanless area both blocking the flow passage are alleviated in the two selected optimized RPT runners. The total pressure head associated with the intensity of vortices is deceased in the optimized runner, resulting in the improved S-shape characteristic. Runner with higher arches and negative blade lean angle of leading edge is conducive to the smooth streamline and avoidance of the flow separation.Funder: National Natural Science Foundation of China (52509133); Natural Science Foundation of the Jiangsu Higher Education Institutions of China Programme - General Programme (24KJD570001); Jiangsu Provincial Double-Innovation Doctor Program (JSSCBS20221363); Yangzhou Lv Yang Jin Feng Ji Hua (YZLYJFJH2021YXBS118)</p
Stuck in the driving seat : Results from a semi-urban living lab experiment with mobility services
No full textThe urgency of the climate crisis necessitates new forms of mitigation, and within the transport sector, a key measure is to reduce car use. This study presents empirical findings from a 10-month living lab experiment in which participants residing in a semi-urban area were challenged to halve their car trips while gaining access to new mobility and accessibility services. The results indicate that car trips were not significantly reduced despite high levels of motivation among participants, and the offered services were not integrated into participants' everyday life. These findings underscore two key points. First, reducing car dependency and transitioning to sustainable mobility in semi-urban areas requires more than the introduction of new technologies or services. Successful integration of new mobility and accessibility services demands a comprehensive understanding of local everyday practices and their associated mobility practices. Second, it is essential to acknowledge the established role of the car in everyday life in semi-urban contexts and to promote a willingness to adapt planning and infrastructure in ways that prioritise sustainable modes of transport, and restrict car access and use. We argue that without addressing these issues, efforts to reduce car use through adding new mobility services are likely to fall short, limiting their effectiveness in achieving sustainable mobility goals
Biofunctionalization of SLM Ti–40Nb alloy through hydroxyapatite-modified plasma electrolytic oxidation coating
No full textThis study reports the successful development of bioactive coatings on in-situ alloyed Ti-40Nb substrates fabricated via selective laser melting (SLM) using plasma electrolytic oxidation (PEO). Two electrolytes were employed for PEO processing: phosphate–silicate (PS) and phosphate–silicate–hydroxyapatite (PSHA). A comparative evaluation was performed to investigate the influence of electrolyte composition on surface morphology, corrosion resistance, and biological performance. The incorporation of hydroxyapatite (HAp) in the PSHA electrolyte significantly modified the coating structure, resulting in reduced porosity, increased surface roughness, and enhanced wettability. X-ray diffraction analysis confirmed the formation of TiO₂ (anatase and rutile) and Nb₂O₅ phases, with a higher rutile fraction observed in the HAp-incorporated coatings due to intensified plasma discharges. Electrochemical testing in simulated body fluid (SBF) demonstrated improved corrosion resistance for the HAp-containing samples, as evidenced by lower corrosion current density and passivation current values. In vitro assays with MC3T3 pre-osteoblast cells further revealed superior cell viability and proliferation on the HAp-incorporated coatings, attributed to the synergistic effects of roughened topography and the sustained release of bioactive ions. Overall, the PEO-modified Ti40Nb samples exhibited enhanced corrosion protection and cytocompatibility, underscoring their strong potential as next-generation Ti-based orthopedic implant materials.