The mechanical properties of the sclera play a critical role in supporting the ocular structure and maintaining its shape. However, non-invasive measurements to quantify scleral biomechanics remain challenging. Recently introduced multi-directional optical coherence elastography (OCE) combined with an air-coupled ultrasound transducer for excitation of elastic surface waves was used to estimate phase speed and shear modulus in ex vivo rabbit globes (n = 7). The scleral phase speed (12.1 ± 3.2 m/s) was directional-dependent and higher than for corneal tissue (5.9 ± 1.4 m/s). In the tested locations, the sclera proved to be more anisotropic than the cornea by a factor of 11 in the maximum of modified planar anisotropy coefficient. The scleral shear moduli, estimated using a modified Rayleigh-Lamb wave model, showed significantly higher values in the circumferential direction (65.4 ± 31.9 kPa) than in meridional (22.5 ± 7.2 kPa); and in the anterior zone (27.3 ± 9.3 kPa) than in the posterior zone (17.8 ± 7.4 kPa). The multi-directional scanning approach allowed both quantification and radial mapping of estimated parameters within a single measurement. The results indicate that multi-directional OCE provides a valuable non-invasive assessment of scleral tissue properties that may be useful in the development of improved ocular models, the evaluation of potential myopia treatment strategies, and disease characterization and monitoring.

The fabrication of multi-component film with colloidal particles could be inconvenient. A novel \"swell-permeate\" (SP) strategy was proposed to form homogeneous multi-component films. The SP strategy allows colloidal particles to fit into the polymer network by stretching the polymer chains assisted by water. We demonstrated the strategy by creating films with polysaccharide substrates as β-cyclodextrin grafted chitosan (CS) with nanocellulose. The addition of nanocellulose significantly increased the mechanical properties and the barrier performance of the films. The size of nanocellulose particles in affecting mechanical properties was investigated by applying different length of cellulose nanocrystal (CNC), the longer of which, due to denser physical entanglements, showed a better increase to the film in the elastic modulus and tensile strength to 4.54-fold and 5.71-fold, respectively. The films were also loaded with ethyl-p-coumarate (EpCA) and had an enhanced performance in anti-microbial for Altenaria alternata, Salmonella typhi, and Escherichia coli. The anti-oxidative property was increased as well, and both effects were valid both in vitro and in ready-to-eat apples. The strategy provides a practical and convenient method for fabricating colloidal particle containing films, and the novel idea of \"swell-permeate\" is potentially regarded as a new solution to the challenge of ready-to-eat food quality maintenance.

This study examines the corrosion characteristics of weakly cemented sandstone under alkaline conditions, evaluating the effects of varying pH levels on its macroscopic degradation, micro-porosity, and mechanical properties, notably uniaxial compressive strength. Findings reveal that heightened alkalinity exacerbates rock damage, although a temporary alleviation in mass loss occurs between pH 9 and 11 due to pore clogging by complexes formed from cations like Ca2+ and Mg2+.Increased alkalinity induces marked changes in pore features, with an observed rise in pore numbers, transformation of pore shapes from elongated to more spherical, and adjustments in porosity, pore size, and roundness. Furthermore, the study confirms a decline in both the rock\'s compressive strength and elastic modulus as pH rises. These revelations shed light on the role of pH in the corrosion behavior of weakly cemented sandstone under alkaline conditions, providing a fresh perspective for understanding its corrosion mechanisms in such environments.

Foam rolling have gained popularity among elite athletes, but the effect of the speed parameter of foam rolling has not yet been determined. Our objective was to investigate the impact of different application speeds of foam roller on the mechanical properties of the quadriceps femoris muscle. Eighteen male professional basketball athletes (age 23 ± 4 years, body mass index 24.43 ± 1.59 kg/m2) participated in this study. We used a crossover design to randomize the order of the treatment speeds (30 beats per minute-FAST, 15 beats per minute-SLOW, and a self-determined speed-SELF) with a one-week washout period between each session. We measured dominant quadriceps femoris muscle tone, elasticity, and stiffness using the Myoton device before and after the interventions. We found that the average rate for SELF was 33±10 beats per minute, making SELF the fastest. All application speeds showed similar results in pre-intervention measurements of the mechanical properties of the tissues (P > 0.05). However, post hoc analysis revealed that a decrease was evident in SLOW compared to SELF in muscle tone in post-intervention measurements (P = 0.037). Also, we noted that comparison of pre- and post-intervention on FAST and SLOW showed a significant reduction in muscle tone (P = 0.002, P = 0.008). Slower foam rolling prior to training or competition may lead to a delay in the reaction time due to the reduction in tonus, that can increase the injury risks. Alternatively, the significant reduction in tonus may be useful in regulating the increased tonus after training and competition.

Hydrogels are highly sought-after absorbent materials for absorbent pads; however, it is still challenging to achieve a satisfactory balance between mechanical performance, water absorption capacity, and active functionalities. In this work, we presented double-network hydrogels synthesized through acrylic acid (AA) polymerization in the presence of quaternized cellulose nanofibrils (QCNF) and Fe3+. Spectroscopic and microscopic analyses revealed that the combined QCNF and Fe3+ facilitated the formation of double-network hydrogels with combined chemical and physical crosslinking. The synergistic effect of QCNF and Fe3+ resulted in impressive mechanical properties, including tensile strength of 1.98 MPa, fracture elongation of 838.8 %, toughness of 7.47 MJ m-3, and elastic modulus of 0.35 MPa. In comparison to the single-network PAA hydrogel, the PAA/QCNF/Fe3+ (PQFe) hydrogels showed higher and relatively stable swelling ratios under varying pH levels and saline conditions. The PQFe hydrogels exhibited notable antioxidant activity, as evidenced by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and demonstrated effective antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). These hydrogels show promising potential as an absorbent interlayer in absorbent pads for active food packaging.

Purpose: The primary objective of the conducted research was to develop an urological stent design for the treatment of male ure-thral stenosis. Given the variable loading conditions inside the urethra, the proposed stent should maintain normal tissue kinetics and obstruct the narrowed lumen. The suitable selection for the stent material significantly influences the regeneration and proper remodeling of the urethral tissues. Methods: In this work, the mechanical characteristics of some polymer materials were studied, including: polydi-oxanone (PDO) and poly(L-lactide) (PLLA)/polycaprolactone (PCL) composite. The obtained mechanical properties for static tensile testing of the materials, allowed the determination of such parameters as Young\'s modulus (E), tensile strength (R m) and yield strength (R e). Subsequently, the design of a urological stent was developed, for which a numerical analysis was carried out to check the behaviour of the stent during varying loads prevailing in the urethra. Result: The research indicated that PDO has better mechanical properties than the proposed PLLA/PCL composite. The numerical analysis results suggested that the developed stent design can be successfully used in the treatment of male urethral stenosis. The obtained stress and strain distributions in the numerical analysis confirm that the PDO material can be used as a material for an urological stent. Conclusions: The biodegradable polymers can be successfully used in urology. Their advantages over solid materials are their physicochemical properties, the ability to manipulate the rate and time of degradation and the easy availability of materials and manufacturing technology.

Hydrogel is a kind of degradable hydrophilic polymer, but excessive hydrophilicity leads to larger volume, lower elastic modulus and looser structure, which further affect its use. Especially in the field of biomedical engineering, excessive swelling of the hydrogel can compress the nerves and improve degradation rate resulting in mismatch of tissue growth and released ions. Therefore, anti-swelling hydrogel has been a research hotspot in recent years. This paper reviews the recent research progress on anti-swelling hydrogel, and expounds the application mechanism and preparation method of hydrogel in biomedical engineering, aiming to provide some references for researchers in the field of anti-swelling hydrogel.
水凝胶是一种可降解亲水聚合物，但亲水性过大导致体积变大、弹性模量降低以及结构松散，影响其使用；尤其是在生物医学工程领域，水凝胶的过分溶胀会压迫神经，且降解速率过快，导致释放的离子与组织生长不匹配等问题。因此，抗溶胀的水凝胶是近年来的研究热点，本文综述了抗溶胀水凝胶的近期研究进展，从水凝胶的溶胀机制和制备方法出发，详细阐述其在生物医学工程领域的应用发展，以期为抗溶胀水凝胶领域的研究者提供一些参考与借鉴。.

Given the escalating environmental and safety concerns, friendly protective materials with exceptional mechanical properties, biodegradability, and insensitivity to high temperature have received more and more attention. Here, we report a robust cellulosic gel through the multi-scale integration of cellulose molecular skeleton, nano-reinforced diatomite, and in situ polymerized polyacrylamide molecule. The bottom-up yet cross-scale approach facilitates the formation of cellulosic gel characterized by a highly interconnected hydrogen bond network and nano-enhanced domain, resulting in a tensile strength of up to 13.83 MPa, a Young\'s modulus exceeding 280 MPa, and an impact strength around 12.38 KJ m-1. Furthermore, this gel exhibits structural stability at temperatures up to 130 °C, good flame retardancy, and complete biodegradability within a span of 35 days. The robust cellulosic gel, acting as a pliable protector, demonstrates exceptional protection for human joints. Our study presents a highly efficient and scalable pathway towards the development of sustainable and robust biomass gels, holding immense potential in intelligent-protective wearables and advanced materials science and engineering.

Titanium and its alloys, especially Ti-6Al-4V, are widely studied in implantology for their favorable characteristics. However, challenges remain, such as the high modulus of elasticity and concerns about cytotoxicity. To resolve these issues, research focuses on β-type titanium alloys that incorporate elements such as Mo, Nb, Sn, and Ta to improve corrosion resistance and obtain a lower modulus of elasticity compatible with bone. This review comprehensively examines current β titanium alloys, evaluating their mechanical properties, in particular the modulus of elasticity, and corrosion resistance. To this end, a systematic literature search was carried out, where 81 articles were found to evaluate these outcomes. In addition, this review also covers the formation of the alloy, processing methods such as arc melting, and its physical, mechanical, electrochemical, tribological, and biological characteristics. Because β-Ti alloys have a modulus of elasticity closer to that of human bone compared to other metal alloys, they help reduce stress shielding. This is important because the alloy allows for a more even distribution of forces by having a modulus of elasticity more similar to that of bone. In addition, these alloys show good corrosion resistance due to the formation of a noble titanium oxide layer, facilitated by the incorporation of β stabilizers. These alloys also show significant improvements in mechanical strength and hardness. Finally, they also have lower cytotoxicity and bacterial adhesion, depending on the β stabilizer used. However, there are persistent challenges that require detailed research in critical areas, such as optimizing the composition of the alloy to achieve optimal properties in different clinical applications. In addition, it is crucial to study the long-term effects of implants on the human body and to advance the development of cutting-edge manufacturing techniques to guarantee the quality and biocompatibility of implants.

OBJECTIVE: To assess the impact of elastic gradients formed among restorative material, cement, and substrate on the fracture resistance of tri-layer restorative systems.
METHODS: Four CAD/CAM materials were utilized, two glass-ceramics (IPS e.max CAD, Vita Suprinity) and two resin-ceramic hybrids (Vita Enamic, Lava Ultimate). Their fracture resistance was examined by biaxial flexure (n = 8) and Hertzian indentation (n = 10) tests. Statistical analysis was conducted using ANOVA and Tukey tests (p = 5 %). Finite element analysis (FEA) was employed to simulate the Hertzian indentation test and elucidate the stress-fields formed on the intaglio surface below the loading area.
RESULTS: The biaxial flexural strength (MPa) of glass-ceramics exceeded the hybrid materials (e.max 417a, Suprinity 230b, Enamic 138c, and Lava Ultimate 183bc). Conversely, the load-bearing capacity (N) of the materials bonded to dentin analog demonstrated the opposite trend, with the hybrid materials achieving superior results (e.max 830 C, Suprinity 660D, Enamic 1822B, and Lava Ultimate 2593 A). The stress-fields observed by FEA were coherent with the experimental results for Hertzian flexural stresses (MPa): e.max 501 A, Suprinity 342 C, Enamic 406B, whereas no tensile stress was observed at the intaglio surface of Lava Ultimate.
CONCLUSIONS: Detailed analysis of the fracture resistance of the tri-layer restorative systems showed that the elastic gradients play a more significant role than the flexural strength of the restorative materials. The coherence of the elastic moduli between the restorative material and supporting structures results in reduced tensile stress concentration at the intaglio surface beneath the loading area and enhances the ability to withstand load.