Weak Properties Research Articles

One-Step Formed Janus Hydrogel with Time-Space Regulating Properties for Suture-Free and High-Quality Tendon Healing.

Janus hydrogels have promising applications in tendon healing and anti-peritendinous adhesions. However, their complicated preparation methods, weak mechanical properties, and unstable adhesion interfaces have severely limited their application in suture-free and high-quality tendon healing. In this work, by controlling the interfacial distribution of free -COOH groups and cationic-π structures on both sides of the hydrogels, a series of PZBA-EGCG-ALC Janus hydrogels with varying degrees of asymmetric properties are successfully prepared using a simple and efficient one-step synthesis method. The tensile strength and elongation at the break of the Janus hydrogel are as high as 0.51 ± 0.04 MPa and 922.89 ± 28.59%. In addition, the Janus hydrogel can achieve a high difference in adhesion strength (nearly 20-fold) while maintaining a strong adhesion strength on their bottom sides (up to 524.8 ± 33.1 Jm-2). In the spatial dimension, its excellent mechanical compliance and one-sided adhesion behavior can provide effective mechanical support and physical barriers for the injured Achilles tendons. More importantly, the Janus hydrogel can also minimize early inflammation generation in the time dimension via its ROS-responsive PZBA-EGCG prodrug macromolecules. This study provided a more effective and convenient suture-free strategy for constructing Janus hydrogels to promote high-quality tendon healing.

Facile Synthesis of Palladium Nanorods: Self-Assembly into Thin 2D Layers for SERS Sensing

This study presents a simple, high-throughput synthesis approach for fabricating palladium (Pd) nanomaterials with anisotropic shapes, specifically Pd nanorods, via a self-assembly process. This method avoids the use of reducing agents, surface functionalization, and stabilizing agents. Palladium–poly(methyl methacrylate) (Pd-PMMA) nanocomposites were successfully synthesized using a vapor-induced phase separation (VIPS) method. The formation of Pd nanorods was controlled by tuning key parameters, such as the Pd precursor concentration, choice of solvents, and spin coating speed. Notably, the resulting nanorods exhibited high reproducibility and ultrasensitivity as a surface-enhanced Raman scattering (SERS) platform, achieving an enhancement factor of approximately 1.8 × 105, despite the relatively weak plasmonic properties of Pd. This work represents a novel, facile strategy for Pd nanorod synthesis, offering new potential for the design of Pd-based nanosensors for chemical sensing applications.

Diagonal property and weak point property of higher rank divisors and certain Hilbert schemes

In this paper, we introduce the notion of the diagonal property and the weak point property for an ind-variety. We prove that the ind-varieties of higher rank divisors of integral slopes on a smooth projective curve have the weak point property. Moreover, we show that the ind-variety of (1,n)-divisors has the diagonal property and is a locally complete linear ind-variety and calculate its Picard group. Furthermore, we obtain that the Hilbert schemes of a curve associated to the good partitions of a constant polynomial satisfy the diagonal property. In the process of obtaining this, we provide the exact number of such Hilbert schemes up to isomorphism by proving that the multi symmetric products associated to two distinct partitions of a positive integer n are not isomorphic.

Bioactivities of Nostoc sp. polysaccharides: Anti-inflammatory, wound healing, cytoprotective, and anticoagulant effects.

Polysaccharides from various cyanobacterial species have attracted attention for their potential health benefits. In this study, polysaccharide extracts from a freshwater Nostoc sp. were explored for their potential in immunomodulation relevant to skincare, and particularly wound care. Nostoc sp. polysaccharides (NSPs) were tested in various cellular and molecular assays using RAW264.7 macrophages and skin cell lines (HDF, HaCaT). Polysaccharides from the Nostoc sp. outer layer (OL) and inner fluid (IF) significantly enhanced cell proliferation and migration of HDF. HaCaT scratch-wound healing improved with certain polysaccharide extracts. Inner fluid fractions IF-2B and IF-3B polysaccharides demonstrated anti-inflammatory effects in RAW264.7 cells, while IF-1B reduced TNF-α and IL-8 expression in HaCaT cells. TNF-α, though not promoting cell proliferation, positively impacted phagocytosis and NO production. NSPs exhibited weak anticoagulation properties, and fraction IF-1B with monomer composition (Ara/3.0: Glc/23.7: Man/20.3: GlcA/28.0) accelerated wound healing; importantly, OL-1B along with all of the IF cold and hot-extracted fractions were non-cytotoxic, suggesting significant potential for developing skin therapeutics, including pharmaceutical and cosmetic products, based on active compounds from Nostoc sp.. The study underscores the underexplored potential of Nostoc sp. extracts in skincare and highlights the potential benefits of these bioactive components for therapeutic applications.

Ergodicity and Mixing Properties for SDEs with α-StableLévy Noises

In this paper, we consider a class of stochastic differential equations driven by multiplicative α-stable (0<α<2) Lévy noises. Firstly, we show that there exists a unique strong solution under a local one-sided Lipschitz condition and a general non-explosion condition. Next, the weak Feller and stationary properties are derived. Furthermore, a concrete sufficient condition for the coefficients is presented, which is different from the conditions for SDEs driven by Brownian motion or general squared-integrable martingales. Finally, some ergodic and mixing properties are obtained by using the Foster–Lyapunov criteria.

Strong and tough polyvinyl alcohol hydrogels with high intrinsic thermal conductivity

Although polyvinyl alcohol (PVA) hydrogels display huge potential in tissue engineering, flexible and wearable electronic devices and soft robotics, their low intrinsic thermal conductivity and weak mechanical properties severely limit their wider applications in these areas. Herein, a Hofmeister effect-assisted “directional freezing-stretching” tactic is employed for simultaneously enhancing the intrinsic thermal conduction and mechanical properties of PVA hydrogels. The hydrogels are obtained through directional freezing followed by salting-out treatment and subsequent mechanical stretching and salting-out (DFS). The DFS PVA hydrogel with 15 wt% of PVA and a stretching ratio of 4 (DFS4) exhibits the highest thermal conductivity of 1.25 W/(m·K), which is 2.4 and 2.8 times that of PVA hydrogel prepared through frozen-thawed (FT) [0.52 W/(m·K)] and frozen-salted out (FS) [0.45 W/(m·K)] methods, respectively. The DFS4 PVA hydrogel also possesses greatly improved mechanical performances, exhibiting an elongation at break of 163.1%. In addition, the tensile strength, toughness, and elastic modulus of DFS4 PVA hydrogel significantly increase to 27.1 MPa, 25.3 MJ·m-3, and 21.5 MPa from 0.4 MPa, 0.32 MJ·m-3, and 0.07 MPa for FT PVA hydrogels, respectively. It is elucidated that the salting-out effect generates hydrophobic and crystalline regions, while directional freezing and stretching enhance the chain orientation in the DFS strategy. These effects synergistically contribute to the improvement of thermal conductivity and mechanical properties of PVA hydrogels.

Synthesis and Anticancer Activity Evaluation of N-(3,4,5- Trimethoxycinnamoyl)anthranilic Acid Derivatives

There is an urgent need to search for more efficient, better-tolerated anticancer drugs. Tranilast, a synthetic analog of tryptophan metabolite, has been shown to inhibit the growth of various cancer cells. In our previous study, the tranilast analog TRA01 [N-(3,4,5- trimethoxycinnamoyl)anthranilic acid] was identified as a promising agent against the proliferation of MCF-7 and HepG2 cell lines along with good binding affinity on the transforming growth factor beta 1 (TGFβ1) target. To further explore the structure-activity relationship, a series of N-(3,4,5- trimethoxycinnamoyl)anthranilic acid derivatives (5a–i) were successfully synthesized via a two-step synthetic procedure based on N-acylation and Knoevenagel-Doebner reactions and their structures were determined using 1 H-NMR, 13C-NMR, and MS spectra. The derivatives (5a–i) were evaluated for in vitro activity using MTT assay and in silico docking on TGFβ1 target by AutoDockTools–1.5.6 software. The bioactivity results of 5a–i showed 12.30–27.04% and 19.13–46.23% inhibition on proliferation of MCF-7 and HepG2 cell lines at 100 µM concentration, respectively, with the fluorinated derivatives (5a and 5e) possessing the strongest inhibitory activities. The molecular docking also found the best binding affinity of 5a (-8.70 Kcal/mol) and 5e (-8.71 Kcal/mol) on the TGFβ1 target. The SAR result revealed that substituents on the benzene ring of anthranilic acid were not favored for anticancer activity. Although these derivatives exhibited weak anticancer properties, the good binding affinity to the TGFβ1 target suggested certain potential of this scaffold for further study on this target.

Assessment of mechanical properties and durability of compressed mud bricks stabilized with stone dust, wheat straw, and cement

For millennia mud has been utilized to make brick for the construction of both residential as well as architectural purposes. However, concerns regarding their vulnerability to different kinds of hazards due to their weak mechanical properties and durability have emerged. This study addressed the global challenge of developing sustainable and affordable construction materials, particularly in resource-constrained regions. This research aim was to enhance the mechanical properties and durability of compressed mud bricks through a partial replacement technique by incorporating locally available materials like stone dust, wheat straw, and cement. A total of nine combinations were studied. Stone dust was used as 10%, 20%, and 30% by weight. Wheat straw was used in 0.5%, 1%, and 1.5% by weight. Cement was added in a fixed amount of 5% by weight throughout. Among the nine combinations, the one showing maximum compressive strength and minimum water absorption for unit brick was selected for further study. For comparison purposes, control mix samples (including 5% of cement) were also prepared. The combination selected after the tests was 20% stone dust, 0.5% wheat straw, and 5% cement. The selected combination and control mix compressed mud bricks were further evaluated through various tests such as flexural strength test on unit brick, water jet test on unit brick, compression strength test on masonry prism, triplet test, and diagonal shear test on masonry wallet was carried out. The increase in compressive strength, modulus of elasticity, shear strength, and modulus of rupture of masonry composed of the compressed mud bricks made up of the selected combination was 46.43%, 97.05%, 56.40%, and 27.1% respectively as compared to the control mix. By incorporating locally available materials the mechanical properties and durability of traditional mud bricks were enhanced. This work bridges traditional mud brick composition with modern engineering insight by providing a scalable, cost-effective, environmentally friendly, application to disaster-prone and rapidly urbanizing areas worldwide.

Enhancement of Biopolymer Film Properties Using Spermidine, Zinc Oxide, and Graphene Oxide Nanoparticles: A Study of Physical, Thermal, and Mechanical Characteristics.

One of the main limitations of biopolymers compared to petroleum-based polymers is their weak mechanical and physical properties. Recent improvements focused on surmounting these constraints by integrating nanoparticles into biopolymer films to improve their efficacy. This study aimed to improve the properties of gelatin-chitosan-based biopolymer layers using zinc oxide (ZnO) and graphene oxide (GO) nanoparticles combined with spermidine to enhance their mechanical, physical, and thermal properties. The results show that adding ZnO and GO nanoparticles increased the tensile strength of the layers from 9.203 MPa to 17.787 MPa in films containing graphene oxide and zinc oxide, although the elongation at break decreased. The incorporation of nanoparticles reduced the water vapor permeability from 0.164 to 0.149 (g.m-2.24 h-1). Moreover, the transparency of the layers ranged from 72.67% to 86.17%, decreasing with higher nanoparticle concentrations. The use of nanoparticles enhanced the light-blocking characteristics of the films, making them appropriate for the preservation of light-sensitive food items. The thermal properties improved with an increase in the melting temperature (Tm) up to 115.5 °C and enhanced the thermal stability in the nanoparticle-containing samples. FTIR analysis confirmed the successful integration of all components within the films. In general, the combination of gelatin and chitosan, along with ZnO, GO, and spermidine, significantly enhanced the properties of the layers, making them stronger and more suitable for biodegradable packaging applications.

Deformation analysis on dispersive clamping for CFRP circular cell honeycombs based on finite element simulations

Dispersive clamping can meet the precise positioning requirement for CFRP circular cell honeycombs due to its discontinuity, but faces complex clamping deformation due to its weak rigidity and heterogeneous properties. Clamping deformation analysis plays a crucial role in guiding fixture optimization and improving machining accuracy. In this paper, an equivalent alternative to adhesive bonding between cells is developed to simulate the mechanical behavior of the resin connecting the cells. The simulation results demonstrate that the proposed method effectively predicts the response of honeycombs under shear load. Further, a FEA model for clamping is developed, which accounts for the cohesive contact between cells. The results show that dispersive internal clamping has a great effect on shear deformation and load transfer paths of honeycombs. By optimizing relevant parameters, the shear deformation of the clamped cells can be restricted and the RMS of the deformation in the Z-direction can be reduced by up to 13.62%.

Physicochemical Characterization of Gallstone Surfaces to Predict Their Interaction with Salmonella Typhi.

Salmonella Typhi can adhere to and build biofilms on the surface of gallstones causing abnormal gallbladder mucosa, which could lead to carcinogenesis. The surface physicochemical properties of microbial cells and materials have been shown to play a crucial role in adhesion. Therefore, the purpose of this study was to investigate, for the first time, the surface properties of nine gallstones and to evaluate the influence of these parameters on the theoretical adhesion of S. Typhi to gallstone surfaces. The physicochemical properties were determined by SEM-EDX and contact angle measurements (CAM) while the predictive adhesion of S. Typhi on gallstones was estimated using the XDLVO approach. SEM-EDX analysis revealed that cholesterol is the principal component on the surface of all gallstones, with carbon and oxygen as the main elements. Aluminum was detected as a trace element in only three gallstones: GS2, GS4, and GS5. S. Typhi CIP5535 has a hydrophilic character (ΔGiwi = 33.54mJm-2), as well as strong electron donor (γ- = 55,80mJ m-2) and weak electron acceptor properties (γ+ = 1,95mJ m-2). Regarding gallstones, it was found that they have a hydrophobic character (ΔGiwi between -29,9mJm-2 and -75,2mJ m-2), while their electron donor/acceptor characters change according to each gallstone. Predictive adhesion showed that all gallstones could be colonized by S. Typhi except GS1, GS5, and GS6 . Understanding the interfacial phenomena implicated in the process of bacterial adhesion makes it possible to limit or even inhibit the adhesion of S. Typhi on gallstone surfaces.

On the composition operator with variable integrability

<p>In this article, we considered a class of composition operators on Lebesgue spaces with variable exponents over metric measure spaces. Taking advantage of the compatibility between the metric-measurable structure and the regularity properties of the variable exponent, we provided necessary and sufficient conditions for this class of operators to be bounded and compact, respectively. In addition, we showed the usefulness of the variable change to study weak compactness properties in the framework of non-standard spaces.</p>

Toughening hydrogels through a multiscale hydrogen bonding network enabled by saccharides for a bio-machine interface.

Hydrogels have considerably emerged in a variety of fields, but their weak mechanical properties severely restrict the wide range of implementation. Herein, we propose a multiscale hydrogen bonding toughening strategy using saccharide-based materials to optimize the hydrogel network. The monosaccharide (glucose) at the molecular scale and polysaccharide (cellulose nanofibrils) at the nano/micro scale can effectively form hydrogen bonds across varied scales within the hydrogel network, leading to significantly enhanced mechanical properties. Besides, the toughened hydrogels present excellent environmental resilience and bad solvent resistance, allowing them to retain their performance in various severe environments. Notably, after being exchanged with a bad solvent such as ethanol, the alcogel exhibits strain-depended vivid interference color, allowing it to function as a mechano-optical sensor. Finally, this strategy has been shown to be adaptable across multiple material systems, and the resulting hydrogels have potential as a bioelectronic interface for long-term stable recording of physiological signals, highlighting the potential of sustainable biomaterials in designing high-quality hydrogels for advanced applications.

Investigating the Effectiveness of Cement Kiln Dust as an Expansive Soil Stabilizer in Road Construction

This study was conducted to investigate the effect of CKD on weak subgrade soil properties, to characterize the untreated soil and CKD, and to determine optimum CKD content that will achieve effective stabilization. The CKD was obtained from Tororo cement factory and the soil sample was obtained from one of the dumping sites along Kyenjojo-Fort-Portal road at Km 23+700 in Uganda. According to classification tests, the soil is an A-7-6. Using British Standard Heavy (BSH) compaction energy, the effect of varying concentrations of CKD on the soil properties was investigated with respect to compaction characteristics, California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) tests. The natural soil exhibited medium expansive properties, with a liquid limit of 53.6% and plasticity index of 27.3%. Adding Cement Kiln Dust (CKD) significantly improved soil properties, reducing liquid limit and plasticity index. CKD also enhanced compaction characteristics, unconfined compressive strength (UCS), and California Bearing Ratio (CBR), attributed to pozzolanic reactions and cementitious compound formation. Cement Kiln Dust can stabilize and improve the engineering properties of weak subgrade soils with adequate reactive SiO2 and Al2O3 so that in presence of water the two react with CaO to form cementitious properties.

Role of silane compatibilization on cellulose nanofiber reinforced poly (lactic acid) (PLA) composites with superior mechanical properties, thermal stability, and tunable degradation rates.

Poly (lactic acid) (PLA) is a widely produced bio-based polymer known for its biodegradability and renewability, but its brittleness, low heat resistance, and weak mechanical properties limit its broader use. To address these challenges, TEMPO-oxidized cellulose nanofibers (TOCNF) were extracted from dissolving pulp using TEMPO oxidation and high-pressure homogenization. These TOCNF were modified with silane to reduce hydrophilicity and improve compatibility with PLA. The resulting silane modified TOCNF (S-TOCNF) were incorporated into PLA via solution casting to form S-TOCNF/PLA composite. Characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) showed that S-TOCNF improved crystallization, compatibility, and enhanced the composite's mechanical properties. At 3 % S-TOCNF content, the S-TOCNF/PLA composites developed in this study achieve a balanced enhancement in mechanical properties, the tensile strength increased by 35.78 %, elongation at break by 66.25 %, and modulus by 25.99 % compared to pure PLA. Thermal stability improved, with decomposition temperature rising to 340 °C, while maintaining over 50 % light transmittance. Additionally, the degradation rate could be controlled by varying S-TOCNF content. This study demonstrates the potential of S-TOCNF to significantly enhance the mechanical, thermal, and degradation properties of PLA-based composites.

Anti-seepage reinforcement property and pollution control effect of bio-cemented fracture zone in electrolytic manganese residue dump

The heavy metal (HM) pollutants in electrolytic manganese residue (EMR) can easily diffuse through the seepage channel of the dump under the leaching action of rainfall. Particularly, the fracture zone, as one of the widely distributed seepage channels in the manganese residue dump (MRD), poses a greater threat to the ecological environment due to its weak mechanical properties, strong ductility, and numerous fractures. In this study, the microbially induced calcium carbonate precipitation (MICP) method was used for anti-seepage reinforcement of the fracture zone in an MRD to be constructed. The optimal conditions for the anti-seepage reinforcement of the fracture zone using the MICP method were proposed, and the control effect of the bio-cemented fracture zone on the major HM pollutant in the leachate of EMR was illustrated. Results showed that after grouting at a rate of 3 mL/min for 12 cycles with a grouting slurry of high urease activity (9 mM urea/min) and high cementation solution concentration (1.5 mol/L), the permeability coefficient of the fracture zone decreased from 10−4 to 10−5, and the unconfined compressive strength was approximately 5.58 times that of uncemented. Furthermore, the cubic calcite crystal clusters with high purity, good stability, dense arrangement, and high cementation properties were generated using the optimal conditions, and the pores were transformed from long columnar to spherical pores. Additionally, the Mn2+ concentration in the effluent from the fracture zone at the stabilization stage was only 663 mg/L, significantly lower than that of the leachate of EMR, and the risk of leaching changed from very high risk to low risk. The research outcomes can provide guidance and reference for laboratory model testing and in-situ testing of bio-cemented fracture zone, and it is expected to provide the theoretical and technological support for green and economic anti-seepage reinforcement of the fracture zone.

Enhancing nerve repair with artificial nerve conduits: A bridging technique without relying on the weak material property – A Biomechanical study

Enhancing nerve repair with artificial nerve conduits: A bridging technique without relying on the weak material property – A Biomechanical study

3D printed elastomers with superior stretchability and mechanical integrity by parametric optimization of extrusion process using Taguchi Method

Abstract This study focused on a modified Fused Deposition Modeling (FDM) 3D printing method, specifically the direct pellet printing of a propylene-based thermoplastic elastomer, Vistamaxx™ 6202, to address challenges like printability and weak mechanical properties. The main objective was optimizing printing parameters and investigating their impact on the mechanical properties. The Taguchi method was used to design the experiments, reducing the required experiments and optimizing printing parameters to maximize desired properties. Three influential parameters were chosen, each changing to three levels. By employing the Taguchi method, the number of experiments decreased from 27 full factorials to 9. Regression models were created through analysis of variance (ANOVA) and verified by additional experiments. Tensile tests were performed according to the ASTM D638 standard. SEM imaging was used to assess interlayer adhesion and structural integrity. The results demonstrated satisfactory interlayer adhesion and structural integrity of the printed samples. Notably, the printed thermoplastic elastomers achieved significant stretchability, reaching up to 5921.3%. The tensile strength was 5.22 MPa, with a tensile modulus of 1.7 MPa. The effect of each parameter and their contribution percentage to the tensile strength, elongation, and elastic modulus were obtained from the variance analysis.

Artinian Gorenstein algebras of socle degree three which have the weak Lefschetz property.

Artinian Gorenstein algebras of socle degree three which have the weak Lefschetz property.

Randomized collective choices based on a fractional tournament

An extension rule assigns to each fractional tournament x (specifying, for every pair of social alternatives a and b, the proportion x ab of voters who prefer a to b) a random choice function y (specifying a collective choice probability distribution for each subset of alternatives), which chooses a from { a, b} with probability x ab . There exist multiple neutral and stochastically rationalizable extension rules. Both linearity (requiring that y be an affine function of x) and independence of irrelevant comparisons (asking that the probability distribution on a subset of alternatives depend only on the restriction of the fractional tournament to that subset) are incompatible with very weak properties implied by stochastic rationalizability. We identify a class of maximal domains, which we call sequentially binary, guaranteeing that every fractional tournament arising from a population of voters with preferences in such a domain has a unique admissible stochastically rationalizable extension.