Search Results (624)

Aggregation of tau protein is a hallmark feature of tauopathies such as Alzheimer’s disease. The microtubule-binding domain of tau plays a crucial role in the tau aggregation process. In this study, we investigated the dual effects of membrane interactions of tau_298–317, a fragment peptide from the microtubule-binding domain, on peptide-induced membrane disruption and membrane-mediated peptide self-assembly. Our results show that neither wild-type tau_298–317 nor its P301L or Ser305-phosphorylated mutants aggregate in the presence of zwitterionic POPC vesicles or cause lipid vesicle leakage, indicating weak peptide–membrane interactions. In contrast, tau_298–317 strongly interacts with negatively charged POPG liposomes, leading to a rapid transition of the peptide conformation from random coils to α-helical intermediate conformation upon membrane adsorption, which may further promote peptide self-association to form oligomers and β-sheet-rich fibrillar structures. Tau_298–317-induced rapid POPG membrane leakage indicates a synergistic process of the peptide self-assembly at the membrane interface and the aggregation-induced membrane disruption. Notably, phosphorylation at Ser305 disrupts favorable electrostatic interactions between the peptide and POPG membrane surface, thus preventing peptide aggregation and membrane leakage. In contrast, the P301L mutation significantly enhances membrane-mediated peptide aggregation and peptide-induced membrane disruption, likely due to alleviation of local conformational constraints and enhancement of local hydrophobicity, which facilitates fast conformational conversion to β-sheet structures. These findings provide mechanistic insights into the molecular mechanisms underlying membrane-mediated aggregation of crucial regions of tau and peptide-induced membrane damage, indicating potential strategies to prevent tau aggregation and membrane rupture by targeting critical electrostatic interactions between membranes and key local regions of tau. Full article

Background/Objectives: Deceleration can cause liver ruptures via ligament traction, with a specific, little-known transverse rupture in segment II of the left lobe being a concern. This study aimed to provide a detailed morphological characterization of these segment II ruptures, analyse their formation mechanisms using autopsy material, and propose a systematic intraoperative assessment method to improve their detection. Methods: This study analysed the autopsy cases of 132 victims of sudden, violent deceleration (falls from height, traffic accidents) performed between 2011 and 2014. Liver injuries were meticulously described, focusing on the morphological characteristics of ruptures (course, shape, depth) and their location relative to hepatic ligaments. Cases with prior liver resection due to injuries were excluded. Results: Liver ruptures were found in 61 of the 132 analysed cases (46.2%). A “new location” for ruptures was identified on the diaphragmatic surface of the left lobe’s segment II, near and along the left coronary and triangular ligaments. This specific type of rupture was found in 14 cases. Overall, 40 cadavers had liver ruptures near ligaments, totalling 55 such distinct ruptures, indicating that some had multiple ligament-associated tears. The incidence of liver rupture at this newly described site was statistically significant. Conclusions: Transverse rupture of the left hepatic lobe’s segment II, in its subdiaphragmatic area, results from ligament “pulling” forces during deceleration and is a characteristic injury. Its presence should be considered following blunt abdominal trauma involving deceleration, and the subdiaphragmatic area of the left lateral lobe requires intraoperative inspection, especially if other ligament-associated liver ruptures are found. Full article

In this study, we investigated the electrochemical corrosion behavior and mechanisms of FeCrNi/WC alloys with varying contents of CTC-S (spherical WC) and CTC-A (angular WC) in a 3.5 wt.% NaCl solution, addressing the corrosion resistance requirements for stainless steel composites in marine environments. The electrochemical test results demonstrate that the corrosion resistance of the alloy initially increases with the CTC-A content, followed by a decrease, which is associated with the formation, stability, and rupture of the passivated film. Nyquist and Bode diagrams for electrochemical impedance spectroscopy confirm that the charge transfer resistance of the passivated film is the primary determinant of the composite’s corrosion performance. A modest increase in CTC-A contributes to the formation of a more heterogeneous second phase, providing a physical barrier and enhancing solid solution strengthening, and thus delaying the cracking and corrosion processes of the passivation film. However, excessive CTC-A content leads to significant dissolution of the alloy’s reinforcement phase and promotes decarburization, resulting in the formation of corrosion pits, craters, and cracks that compromise the passivation film and expose fresh alloy surfaces to further corrosion. When the CTC-A content is 10% and the CTC-S content is 30%, this combination results in minimal degradation in the corrosion performance (0.213 μA·cm²) while balancing the hardness and toughness of the alloy. Additionally, electrochemical evaluations reveal that incorporating angular CTC-A particles at 10 vol% effectively delays the breakdown of the passivation film by mitigating the interfacial galvanic coupling through enhancing the mechanical interlocking at the WC/FeCrNi interface. The CTC-A/CTC-S hybrid system exhibits a remarkable 62% reduction in the pitting propagation rate compared to composites reinforced solely with spherical WC, which is attributed to the preferential dissolution of angular WC protrusions that sacrificially suppress crack initiation at the phase boundaries. Full article

A hydrodynamic homogeneous model has been developed for the motion of mutually impenetrable viscoelastic non-Newtonian fluids taking into account surface tension forces. Based on this model, numerical simulations of cytokinesis hydrodynamics were performed. The cytoplasm is considered a non-Newtonian viscoelastic fluid. The model allows for the calculation of the formation and rupture of the intercellular bridge. Results from an analytical analysis shed light on the influence of the viscoelastic fluid’s relaxation time on cytokinesis dynamics. A comparison of numerical simulation results and experimental data showed satisfactory agreement. Full article

On 18 December 2023, a M_w 6.2 earthquake occurred in close proximity to Jishishan County, located on the northeastern edge of the Qinghai–Tibet Plateau. The event struck the structural intersection of the Haiyuan fault, Lajishan fault, and West Qinling fault, providing empirical evidence for investigating the crustal compression mechanisms associated with the northeastward expansion of the Qinghai–Tibet Plateau. In this study, we successfully acquired a high-resolution coseismic deformation field of the earthquake by employing interferometric synthetic aperture radar (InSAR) technology. This was accomplished through the analysis of image data obtained from both the ascending and descending orbits of the Sentinel-1A satellite, as well as from the ascending orbit of the ALOS-2 satellite. Our findings indicate that the coseismic deformation is predominantly localized around the Lajishan fault zone, without leading to the development of a surface rupture zone. The maximum deformations recorded from the Sentinel-1A ascending and descending datasets are 7.5 cm and 7.7 cm, respectively, while the maximum deformation observed from the ALOS-2 ascending data reaches 10 cm. Geodetic inversion confirms that the seismogenic structure is a northeast-dipping thrust fault. The geometric parameters indicate a strike of 313° and a dip angle of 50°. The slip distribution model reveals that the rupture depth predominantly ranges between 5.7 and 15 km, with a maximum displacement of 0.47 m occurring at a depth of 9.6 km. By integrating the coseismic slip distribution and aftershock relocation, this study comprehensively elucidates the stress coupling mechanism between the mainshock and its subsequent aftershock sequence. Quantitative analysis indicates that aftershocks are primarily located within the stress enhancement zone, with an increase in stress ranging from 0.12 to 0.30 bar. It is crucial to highlight that the structural units, including the western segment of the northern margin fault of West Qinling, the eastern segment of the Daotanghe fault, the eastern segment of the Linxia fault, and both the northern and southern segment of Lajishan fault, exhibit characteristics indicative of continuous stress loading. This observation suggests a potential risk for fractures in these areas. Full article

Field surveys focused on detailed mapping and measurements of coseismic surface ruptures along the causative fault of the 6 February 2023, Mw 7.8 Kahramanmaraş earthquake. The aim was filling gaps in the previously available surface-faulting trace, validating the accuracy of data obtained from remote sensing, refining fault offset estimates, and gaining a deeper understanding of both the local and overall patterns of the main rupture strands. Measurements and observations confirm dominating sinistral strike-slip movement. An integrated and comprehensive slip distribution curve shows peaks reaching over 700 cm, highlighting the near-fault expressing up to 70% of the deep net offset. In general, the slip distribution curve shows a strong correlation with the larger north-eastern deformation of the geodetic far field dislocation field and major deep slip patches. The overall rupture trace is generally straight and narrow with significant geometric complexities at a local scale. This results in transtensional and transpressional secondary structures, as multi-strand positive and negative tectonic flowers, hosting different patterns of the mole-tracks at the outcrop scale. The comprehensive and detailed field survey allowed characterizing the structural framework and geometric complexity of the surface faulting, ensuring accurate offset measurements and the reliable interpretation of both morphological and geometric features. Full article

The 6 February 2023 M_W 7.8 and M_W 7.6 earthquakes in southeastern Türkiye ruptured more than 400 km of the East Anatolian Fault Zone (EAFZ), producing one of the most destructive seismic sequences in recent history. Here, we integrate InSAR data, a new GNSS velocity field, and small-magnitude earthquakes to investigate the coseismic deformation, rupture geometry, and interseismic strain accumulation along the EAFZ. Using elastic dislocation modeling with a variable-strike, multi-segment fault geometry, we constrain the slip distribution of the mainshocks, showing improved fits to the surface displacement compared to the planar fault model. The M_W 7.8 event ruptured a number of fault segments over ~300 km, while the M_W 7.6 event activated a more localized fault system with a peak slip exceeding 15 m. We also model two moderate events (M_W 5.6 in 2020 and M_W 5.3 in 2022) along the southwestern part of the Pütürge segment—an area not ruptured during the 2020 or 2023 sequences. GNSS-derived strain-rate and locking depth estimates reveal strong interseismic coupling and significant strain accumulation in this region, suggesting the potential for a future large earthquake (M_W 6.6–7.1). Similarly, the Hatay region, at the southwestern termination of the 2023 rupture, shows a persistent strain accumulation and complex fault interactions involving the Dead Sea Fault and the Cyprus Arc. Our results demonstrate the importance of combining remote sensing and geodetic data to constrain fault kinematics, evaluate rupture segmentation, and assess the seismic hazard in tectonically active regions. Targeted monitoring at rupture terminations—such as the Pütürge and Hatay sectors—may be crucial for anticipating future large-magnitude earthquakes. Full article

In this study, hybrid composite materials were fabricated using a Scalmalloy^® matrix with fixed multi-walled carbon nanotube (MWCNT, 0.8%) content and varying titanium carbide (TiC; 5%, 10%, 15%) reinforcements via the hot-pressing method. Unlike conventional approaches in the literature that utilize additive manufacturing, this research presents the first successful production of Scalmalloy^®-based hybrid composites through a traditional powder metallurgy method. This method enabled the development of a more homogeneous and equiaxed microstructure. The composites were characterized using SEM, EDS, MAP, and XRD analyses, along with density and microhardness measurements. Mechanical performance was evaluated through Vickers hardness and transverse rupture strength (TRS) tests, while dry sliding wear behavior was examined in detail. The hardness of the 15% TiC + 0.8% MWCNT-reinforced composite increased from 87 HV to 181 HV (a 108% improvement), and TRS increased from 354 MPa to 545 MPa (a 54% improvement). Additionally, wear surface examinations showed that as the reinforcement ratio increased, the severity of surface damage decreased and abrasive wear mechanisms became more dominant. These findings demonstrate that hybrid reinforcement with TiC and MWCNT significantly enhances both mechanical and tribological performance, offering a promising alternative to additive manufacturing for Scalmalloy^®-based composite production. Full article

Low-carbon lath martensite is highly susceptible to hydrogen embrittlement due to the presence of a high density of lath/block boundaries. In this study, I employ a continuum decohesion model to investigate the effects of varying hydrogen concentrations and tensile loads on the cohesive strength of low- and high-angle block boundaries. The thermodynamic properties of the cohesive zone are described using excess variables, which establish a link between atomistic energy calculations and the continuum model for gradual decohesion at a grain boundary. The aim of this study is to develop an in-depth understanding of how hydrogen affects the cohesive strength of block boundaries in a lath martensitic structure by integrating continuum and atomistic computational modeling and to apply the resulting insights to investigate the effects of varying hydrogen concentrations and tensile loads on interface decohesion. I incorporate hydrogen mobility and segregation at low- and high-angle twist boundaries in body-centered cubic (bcc) Fe to quantify the hydrogen-induced effects on progressive decohesion under tensile stress. A constant hydrogen flux through the free surfaces of a bicrystal containing a block boundary is imposed to simulate realistic boundary conditions. The results of the simulations show that, in the presence of hydrogen flux, separation across the block boundaries occurs at a tensile load significantly lower than the critical stress required for rupture in a hydrogen-free lath martensitic structure. Full article

The cryopreservation of ovarian tissues from fish has recently been carried out for several endangered and commercially valuable species. However, previous studies in this context have focused on the cryopreservation of immature ovaries—mainly through slow freezing and vitrification—which requires specialized freezing equipment or higher cryoprotectant concentrations to keep cell viability. Therefore, the aim of this study was to explore a convenient, rapid, efficient and less toxic method for the cryopreservation of ovaries at the stage of vitellogenesis from yellow drum (Nibea albiflora), an economically important marine fish. The ovaries at the stage of vitellogenesis were isolated and cut into blocks of approximately 1 cm³, then cryopreserved with 15% propylene glycol (PG), fetal bovine serum (FBS) and 0.2 M trehalose as cryoprotectants. Finally, the samples were treated using three different freezing procedures, including a −80 °C refrigerator, liquid nitrogen, and their combination. After 7 days, the tissues were thawed and digested, and the cell survival rates and gene expression levels were detected using cell viability assay kits and qRT-PCR, respectively. The results of the viability assay showed that the procedure of ovarian tissue storage at −80 °C in a refrigerator for 1 h, followed by transfer to liquid nitrogen, resulted in the highest cell survival rate (>90%). Furthermore, the germ cells at various phases were of normal size; presented a full, smooth surface and regular shape; and did not show any signs of cell rupture, atrophy, depression, granulation or cavitation. Furthermore, the qRT-PCR results revealed that genes related to reproductive development, such as vasa, foxl2, zp3 and gsdf, were all down-regulated under the optimal protocol, while the expression of the nanos2 gene (which is specifically distributed in oogonia) maintained a higher level, similar to that in the control group. This indicated that the viability of germ stem cells (oogonia) was not weakened after freezing and that oogonia could be isolated from the cryopreserved ovaries for germ cell transplantation. The present study successfully establishes an optimal cryopreservation protocol for ovarian tissues from Nibea albiflora, providing reference for the preservation of ovaries at the stage of vitellogenesis from other species. Full article

Flax fiber reinforcements weaken with aging and microstructural changes, limiting their applications. Here, we examine the effects of microstructure and aging on flax fiber elements’ performance by using 4000-year-old and modern Egyptian flax as references through multi-scale numerical modeling. This study introduces a novel investigation into the tensile stress distribution behavior of archaeological and modern flax yarns. The finite element (FE) model is derived from 3D volumes obtained via X-ray microtomography and tensile testing in the elastic domain. At the microscale, fibers exhibit higher axial stress concentrations around surface defects and pores, particularly in regions with kink bands and lumens. At the mesoscale, fiber bundles show increased stress concentrations at inter-fiber voids and lumen, with larger bundles exhibiting greater stress heterogeneity, especially around pores and surface roughness. At the macroscale, yarns display significant stress heterogeneity, especially around microstructural defects like pores and fiber–fiber cohesion points. Aged fibers from ancient Egyptian cultural heritage in particular demonstrate large fiber discontinuities due to long-term degradation or aging. These numerical observations highlight how porosity, surface imperfections, and structural degradation increase stress concentration, leading to fiber rupture and mechanical failure. This insight reveals how aging and defects impact flax fiber performance and durability. Full article

Tendon ruptures have recently reached incidences of 18–35 cases/100,000 and often lead to adhesion formation during healing. Furthermore, scar formation may result in inferior biomechanics and often leads to re-ruptures. To address these problems, we cultivated rabbit adipose-derived stem cells in a co-culture with rabbit Achilles tenocytes and harvested their secretome. Following a cell-free approach, we incorporated such secretome into an electrospun tube via emulsion electrospinning. These novel implants were characterized by SEM, the WCA, and FTIR. Then, they were implanted in the rabbit Achilles tendon full transection model with an additional injection of secretome, and the adhesion extent as well as the biomechanics of extracted tendons were assessed three weeks postoperatively. The fiber thickness was around 3–5 μm, the pore size 11–13 μm, and the tube wall thickness approximately 265 μm. The WCA indicated slightly hydrophilic surfaces in the secretome-containing layer, with values of 80–90°. In vivo experiments revealed a significant reduction in adhesion formation (−22%) when secretome-treated tendons were compared to DegraPol^® (DP) tube-treated tendons (no secretome). Furthermore, the cross-sectional area was significantly smaller in secretome-treated tendons compared to DP tube-treated ones (−32%). The peak load and stiffness of secretome-treated tendons were not significantly different from native tendons, while tendons treated with pure DP tubes exhibited significantly lower values. We concluded that secretome treatment supports tendon healing, with anti-adhesion effects and improved biomechanics at 3 weeks, making this approach interesting for clinical application. Full article

Salmonella spp. is a pathogen detected in fish, although it is not part of its microbiota; the production and processing environment is the main source of contamination. Brazilian legislation recommends 5 ppm of free residual chlorine for fish washing, but Salmonella can still be present. The objective of this study was to evaluate flaws in the processing flowchart and propose adjustments to reduce Salmonella spp. on the fish surface. Ninety samples were analyzed in a fish processing plant in Mato Grosso, divided into three treatments: (1) conventional processing, (2) modified flowchart, and (3) modified flowchart adapted to the specific plant conditions. Treatment 2 completely eliminated Salmonella spp., while treatment 3 reduced contamination to 3.3%, compared to 56.7% in conventional processing. The success of the modified treatment was only possible due to the main changes implemented in the process, which included the separation of dirty areas (responsible for gill and scale removal) and clean areas (designated for the careful removal of viscera without rupture and for filleting). No statistical difference was found between treatments 2 and 3 (p = 1, CI 0.00000–39.00055), suggesting that the adjusted flowchart can be implemented on a large scale to ensure food safety (OR = ∞, CI = [7.655, ∞], p < 0.001). This study highlights the effectiveness of the adjusted flowchart in reducing Salmonella spp. contamination in fish, with treatment 2 resulting in a complete absence of contamination. Treatment 3 maintained low contamination levels, demonstrating practical applicability in meatpacking plants. Full article

This work studies the fabrication of CoCrFeNiMo high-entropy alloy (HEA) coatings via coaxial powder-fed laser cladding, addressing porosity and impurity issues in conventional methods. The HEA coatings exhibited eutectic/hypereutectic microstructures under all laser power conditions. A systematic investigation of laser power effects (1750–2500 W) reveals that 2250 W optimizes microstructure and performance, yielding a dual-phase structure with FCC matrix and dispersed σ phases (Fe-Cr/Mo-rich). The coating achieves exceptional hardness (738.3 HV_0.2, 3.8× substrate), ultralow wear rate (4.55 × 10⁻⁵ mm³/N·m), and minimized corrosion current (2.31 × 10⁻⁴ A/cm²) in 3.5 wt.% NaCl. The friction mechanism of the CoCrFeNiMo HEA coating is that in high-speed friction and wear, the oxide film is formed on the surface of the coating, and then the rupture of the oxide film leads to adhesive wear and abrasive wear. The corrosion mechanism is the galvanic corrosion caused by the potential difference between the FCC phase and the σ phase. Full article

Strong earthquake activity along fault zones can lead to the displacement of geomorphic units such as gullies and terraces while preserving earthquake event data through changes in sedimentary records near faults. The quantitative analysis of these characteristics facilitates the reconstruction of significant earthquake activity history along the fault zone. Recent advancements in acquisition technology for high-precision and high-resolution topographic data have enabled more precise identification of displacements caused by fault activity, allowing for a quantitative assessment of the characteristics of strong earthquakes on faults. The 1920 Haiyuan earthquake, which occurred on the Haiyuan fault in the northeastern Tibetan Plateau, resulted in a surface rupture zone extending nearly 240 km. Although clear traces of surface rupture have been well preserved along the fault, debate regarding the maximum displacement is ongoing. In this study, we focused on two typical offset geomorphic sites along the middle segment of the Haiyuan fault that were previously identified as having experienced the maximum displacement during the Haiyuan earthquake. High-precision geomorphologic images of the two sites were obtained through unmanned aerial vehicle (UAV) surveys, which were combined with light detection and ranging (LiDAR) data along the fault zone. Our findings revealed that the maximum horizontal displacement of the Haiyuan earthquake at the Shikaguan site was approximately 5 m, whereas, at the Tangjiapo site, it was approximately 6 m. A cumulative offset probability distribution (COPD) analysis of high-density fault displacement measurements along the ruptures indicated that the smallest offset clusters on either side of the Ganyanchi Basin were 4.5 and 5.1 m long. This analysis further indicated that the average horizontal displacements of the Haiyuan earthquake were approximately 4–6 m. Further examination of multiple gullies and geomorphic unit displacements at the Shikatougou site, along with a detailed COPD analysis of dense displacement measurements within a specified range on both sides, demonstrated that the cumulative displacement within 30 m of this section of the Haiyuan fault exhibited at least five distinct displacement clusters. These dates may represent the results of five strong earthquake events in this fault segment over the past 10,000–13,000 years. The estimated magnitude, derived from the relationship between displacement and magnitude, ranged from M_w 7.4 to 7.6, with an uneven recurrence interval of approximately 2500–3200 years. Full article