Bio-based aerogel is a functionalized nanoporous material with environmentally friendly, high surface area, ultra-low density, high porosity, and low thermal conductivity, making it suitable for various applications such as energy-saving buildings, electronic information, separation, adsorption, catalysis, biomedicine, and others. However, the current bio-based chitosan aerogel still faces great challenges in reaching multifunctional improvement to address its intrinsic shortcomings. Herein, we propose a new approach depending upon supramolecular interactions for constructing chitosan/bacterial cellulose aerogels that simultaneously possess superior moisture resistance/fatigue, anti-thermal-shock, and flame retardancy. Specifically, the aerogels demonstrate remarkable characteristics, namely high strength (self-standing itself weight beyond 10,676 times), low thermal conductivity (lowest to 22 mW m-1 K-1 under normal pressure and room temperature), and excellent fatigue resistance (almost negligible permanent deformation at 1 % strain even undergoing compressive cycles up to 10,000 times). On the other hand, the aerogels display exceptional moisture resistance with superhydrophobicity (moisture absorption rate <0.88 % for 160 h at 70 °C and 85 % relative humidity), excellent thermal shock property (withstand cold-hot shock up to 200 cycles with rapid temperature changes between -30 °C and 60 °C), and remarkable fire retardancy (swiftly self-extinguishing in 0.6 s). Additionally, the compressive stress increases to 0.223 MPa at 3 % strain after hydrophobic treatment, representing a 27 % enhancement in mechanical robustness. Further, the mechanism responsible for microstructural evolution has been also established in different strain conditions. This work may provide rich possibilities for developing multifunctional bio-based aerogel for energy-saving buildings.

Low-hysteresis merits can help polymeric gel materials survive from consecutive loading cycles and promote life span in many burgeoning areas. However, it is a big challenge to design low-hysteresis and tough polymeric gel materials, especially for ionogels. This can be attributed to the fact that higher viscosities of ionic liquids (ILs) would increase chain friction of polymeric gels and eventually dissipate large amounts of energy under deformation. Herein, a chemical design of ionogels is proposed to achieve low-hysteresis characteristics in both mechanical and electric aspects via hierarchical aggregates formed by supramolecular self-assembly of quadruple H-bonds in a soft IL-rich polymeric matrix. These self-assembled nanoaggregates not only can greatly reinforce the polymeric matrix and enhance resilience, but also exhibit low-energy-dissipating features under stress conditions, simultaneously benefiting for low-hysteresis properties. These aggregates can also promote toughness and subsequent anti-fatigue properties in response to external cyclic mechanical stimuli. More importantly, these ionogels are presented as a model system to elucidate the underlying mechanism of the low hysteresis and fatigue resistance. Based on these findings, it is further demonstrated that the supramolecular low-hysteresis strategy is universal.

Lightweight materials with high strength and long cyclic lifespan are greatly demanded in practical applications, yet these properties are usually mutually exclusive. Here, we present a strong, lightweight, highly deformation-tolerant, and fatigue-resistant carbon nanotube (CNT) composite enabled by an amorphous/crystalline heterophase carbon shell. In particular, we obtain nanocrystallites with CNT-induced crystalline orientation uniformly embedded within an amorphous matrix by controlled thermal annealing. The heterophase carbon shell effectively alleviates the stress concentration and inhibits crack propagation, which renders our composite superior mechanical properties and high fatigue resistance (106 compression cycles at 20% strain with high stress of 144 kPa, or 5 × 105 cycles at 50% strain with stress up to 260 kPa). This study provides a deep understanding of amorphous-crystalline phase transition and insight into utilizing phase engineering to design and develop other high-performance functional materials such as structural materials and catalysis.

This research primarily focuses on the strength indicators of the bearing structures of ADM-1 special self-propelled rolling stock. The special self-propelled rolling stock used by Uzbek railroads reaching the end of their functional life is a pertinent problem as Uzbekistan\'s railway system is growing rapidly, but there is a lack of enough funds to buy new special self-propelled rolling stock. Hence, it is vital to fix the issues with ADM-1 special self-propelled rolling stock by overhauling them. At the outset, the researchers divided the frame of a special a self-propelled rolling stock into multiple sections. Subsequently, these individual sections were analyzed closely to spot out issues. The precise location of the fatigue defect occurrence on the longitudinal beams was determined by the analysis of the individual sections of the special self-propelled rolling stock. During the motor carriage\'s modernization, which is an approach to extend the service life and improve the durability of special self-propelled rolling stock, this analysis helped in pinpointing exactly the location on the frame where the stress measurements had to be calculated. Pre- and post-modernization calculations were carried out on the vehicle to determine the optimal placement of the reinforcing plates. Additionally, normative calculations were also conducted and a new design mode distinct from the repair loads was implemented. The computation results revealed that the fatigue resistance reserve coefficient and service life value prior to the bearing structure\'s modernization in section 1 were below the required values of n = 1.5 and 1.49, respectively. All the sections of the load-bearing structure fulfilled the fatigue resistance reserve coefficient standards after the modernization. The computational model of the motor carriage\'s structural strength was created in the ANSYS Workbench platform. This research intends to enhance the strength determination procedures and provides recommendations for design and restoration of modern structures of special self-propelled rolling stock.

The study presented herein concerns the mechanical properties of two common polymers for potential biomedical applications, PLA and PETG, processed through fused filament fabrication (FFF)-Material Extrusion (ME). For the uniaxial tension tests carried out, two printing orientations-XY (Horizontal, H) and YZ (Vertical, V)-were considered according to the general principles for part positioning, coordinates, and orientation typically used in additive manufacturing (AM). In addition, six specimens were tested for each printing orientation and material, providing insights into mechanical properties such as Tensile Strength, Young\'s Modulus, and Ultimate Strain, suggesting the materials\' potential for biomedical applications. The experimental results were then compared with correspondent mechanical properties obtained from the literature for other polymers like ASA, PC, PP, ULTEM 9085, Copolyester, and Nylon. Thereafter, fatigue resistance curves (S-N curves) for PLA and PETG, printed along 45°, were determined at room temperature for a load ratio, R, of 0.2. Scanning electron microscope observations revealed fibre arrangements, compression/adhesion between layers, and fracture zones, shedding light on the failure mechanisms involved in the fatigue crack propagation of such materials and giving design reference values for future applications. In addition, fractographic analyses of the fatigue fracture surfaces were carried out, as well as X-ray Computed Tomography (XCT) and Thermogravimetric (TGA)/Differential Scanning Calorimetric (DSC) tests.

OBJECTIVE: This study aimed to reproduce and translate clinical presentations in an in vitro set-up and evaluate laboratory outcomes of mechanical properties (flexural strength, fatigue resistance, wear resistance) and link them to the clinical outcomes of the employed materials in the Radboud Tooth Wear Project (RTWP).
METHODS: Four dental resin composites were selected. 30 discs (Ø12.0 mm, 1.2 mm thick) were fabricated for each of Clearfil TM AP-X (AP), Filtek TM Supreme XTE (FS), Estenia TM C&B (ES), and Lava Ultimate (LU). Cyclic loading (200 N, 2 Hz frequency) was applied concentrically to 15 specimens per group with a spherical steatite indenter (r = 3.18 mm) in water in a contact-load-slide-liftoff motion (105 cycles). The wear scar was analysed using profilometry and the volume loss was digitally computed. Finally, all specimens were loaded (fatigued specimens with their worn surface loaded in tension) until fracture in a biaxial flexure apparatus. The differences in volume loss and flexural strength were determined using regression analysis.
RESULTS: Compared to AP and FS, ES and LU showed a significantly lower volume loss (p < 0.05). Non-fatigued ES specimens had a similar flexural strength compared to nonfatigued AP, while non-fatigued FS and LU specimens had a lower flexural strength (p < 0.001; 95 %CI: -80.0 - 51.8). The fatigue test resulted in a significant decrease of the flexural strength of ES specimens, only (p < 0.001; 95 %CI: -96.1 - -54.6).
CONCLUSIONS: These outcomes concur with the outcomes of clinical studies on the longevity of these composites in patients with tooth wear. Therefore, the employed laboratory test seems to have the potential to test materials in a clinically relevant way.

BACKGROUND: An optimum restoration for reconstructing endodontically treated teeth should provide excellent marginal adaptation, high fracture resistance as well as maximum tooth structure conservation. The purpose of this study was to evaluate the marginal adaptation and fatigue resistance of different coronal restorations in endodontically treated premolars.
METHODS: Thirty sound maxillary first premolars were endodontically treated and received MOD cavities. Teeth were randomly allocated into three groups (n = 10) according to the type of coronal restoration: Group R: polyethylene fibers (ribbond), fibers-reinforced composite (everX posterior) and final layer of nano-hybrid composite. Group O: indirect lithium disilicate overlay and Group C: fiber-post, resin composite restoration, and lithium disilicate crown. Marginal gap assessment was performed before and after thermocycling (5000 cycles) using stereomicroscope. Samples were subjected to stepwise-stress loading starting at 200 N, and increased by 100 N in each step until failure occurred. Statistical analysis was done by One-way ANOVA followed Tukey`s Post Hoc test for multiple comparison. Paired t test was used to compare the marginal adaptation before and after thermocycling. Survival probability was evaluated by Life table survival analysis. Failure mode analysis was performed with Chi-square test.
RESULTS: Marginal gap was significantly the lowest in group R (37.49 ± 5.05) and (42.68 ± 2.38), while being the highest in group C (59.78 ± 5.67) and (71.52 ± 5.18) in before and after thermocycling respectively (P < 0.0001). Fatigue resistance was the highest for group O (1310.8 ± 196.7), and the lowest for group R (905.4 ± 170.51) with a significant difference between groups (P < 0.0001). Crown group had the highest percentage (80%) of catastrophic failure, while, overlay group exhibited the lowest (20%).
CONCLUSIONS: Direct restoration without cuspal coverage using ribbon fibers with short FRC provided better marginal adaptation than indirect overlays and crowns, but fatigue resistance wasn\'t significantly improved. Adhesive ceramic overlays showed the best fatigue performance and the least catastrophic failure rate compared to both direct fiber-reinforced composite and indirect ceramic full coverage restorations.
CONCLUSIONS: Indirect adhesive overlays are a suitable, more conservative restorative option for endodontically treated teeth than full coverage restorations, especially when tooth structure is severely compromised.

OBJECTIVE: Streptozotocin (STZ) is widely used to study diabetic complications. Owing to the nonspecific cytotoxicity of high-dose STZ, alternative models using moderate-dose or a combination of low-dose STZ and a high-fat diet have been established. This study aimed to investigate the effects of these models on muscle function.
METHODS: The muscle function of two STZ models using moderate-dose STZ (100 mg/kg, twice) and a combination of low-dose STZ and high-fat diet (50 mg/kg for 5 consecutive days + 45% high-fat diet) were examined using in vivo electrical stimulation. Biochemical and gene expression analysis were conducted on the skeletal muscles of the models immediately after the stimulation.
RESULTS: The contractile force did not differ significantly between the models compared to respective controls. However, the moderate-dose STZ model showed more severe fatigue and blunted exercise-induced glycogen degradation possibly thorough a downregulation of oxidative phosphorylation- and vasculature development-related genes expression.
CONCLUSIONS: Moderate-dose STZ model is suitable for fatigability assessment in diabetes and careful understanding on the molecular signatures of each model is necessary to guide the selection of suitable models to study diabetic myopathy.

In response to the critical challenges of interfacial impedance and volumetric changes in Li(1+x)AlxTi(2‑x)(PO4)3 (LATP)-based lithium metal batteries, an elastomeric lithium-conducting interlayer fabricates from fluorinated hydrogenated nitrile butadiene rubber (F-HNBR) matrix is introduced herein. Owing to the vulcanization, vapor-phase fluorination, and plasticization processes, the lithium-conducting interlayer exhibits a high elasticity of 423%, exceptional fatigue resistance (10 000 compression cycles), superior ionic conductivity of 6.3 × 10-4 S cm-1, and favorable lithiophilicity, rendering it an ideal buffer layer. By integrating the F-HNBR interlayer, the LATP-based lithium symmetric cells demonstrate an extended cycle life of up to 1600 h at 0.1 mA cm-2 and can also endure deep charge/discharge cycles (0.5 mAh cm-2) for the same duration. Furthermore, the corresponding lithium metal full cells achieve 500 cycles at 0.5 C with 98.3% capacity retention and enable a high-mass-loading cathode of 11.1 mg cm-2 to operate at room temperature.

Pushing intercalation-type cathode materials to their theoretical capacity often suffers from fragile Li-deficient frameworks and severe lattice strain, leading to mechanical failure issues within the crystal structure and fast capacity fading. This is particularly pronounced in layered oxide cathodes because the intrinsic nature of their structures is susceptible to structural degradation with excessive Li extraction, which remains unsolved yet despite attempts involving elemental doping and surface coating strategies. Herein, a mechanochemical strengthening strategy is developed through a gradient disordering structure to address these challenges and push the LiCoO2 (LCO) layered cathode approaching the capacity limit (256 mAh g-1, up to 93% of Li utilization). This innovative approach also demonstrates exceptional cyclability and rate capability, as validated in practical Ah-level pouch full cells, surpassing the current performance benchmarks. Comprehensive characterizations with multiscale X-ray, electron diffraction, and imaging techniques unveil that the gradient disordering structure notably diminishes the anisotropic lattice strain and exhibits high fatigue resistance, even under extreme delithiation states and harsh operating voltages. Consequently, this designed LCO cathode impedes the growth and propagation of particle cracks, and mitigates irreversible phase transitions. This work sheds light on promising directions toward next-generation high-energy-density battery materials through structural chemistry design.