Anisotropic soils exhibit complex mechanical behaviours under various loadsing conditions, e.g., reversible dilatancy, three-dimensional failure strength, fabric anisotropy, small-strain stiffness, cyclic mobility, making it difficult to comprehensively capture these characteristics within a single constitutive model. Failure to capture anisotropic soil behavious may result in poor predictions in geotechnical engineering. Hence, to provide a unified prediction for the mechanical responses of anisotropic sand and clay under both monotonic and cyclic loading conditions, a fabric-based anisotropic constitutive model, i.e., the CASM-CF, is developed within the framework of the standard Clay and Sand Model (CASM) in this paper. Effects of small-strain stiffness and anisotropic elasticity are incorporated into the stiffness matrix to capture the stiffness variation over a wide strain range and reversible dilation. The fabric tensor defined by particle orientation and its evolution law are integrated into the CASM-CF model through the Anisotropic Transformed Stress (ATS) method. The plastic modulus is modified by considering cyclic loading history and stress reverse to better predict the mechanical responses of soils when subjected to cyclic loadings. The newly proposed model is employed to predict the mechanical behaviours of clay and sand under various strain scales and stress paths, including monotonic, cyclic, proportional, and non-proportional loading conditions, in the literature. Conclusions can be drawn that the model performs satisfactorily under various stress paths, and it has the potential to be used in the analysis of practical geotechnical applications of wide range.

Small organic compounds (SOCs) are widespread environmental pollutants that pose a significant threat to ecosystem health and human well-being. In this study, the FrmA gene from Escherichia coli was overexpressed alone or in combination with FrmB in Arabidopsis thaliana and their resistance to multiple SOCs was investigated. The transgenic plants exhibited varying degrees of increased tolerance to methanol, formic acid, toluene, and phenol, extending beyond the known role of FrmA in formaldehyde metabolism. Biochemical and histochemical analyses showed reduced oxidative damage, especially in the FrmA/BOE lines, as evidenced by lower malondialdehyde (MDA), H2O2 and O-2(center dot-) levels, indicating improved scavenging of reactive oxygen species (ROS). SOC treatment led to significantly higher levels of glutathione (GSH) and, to a lesser extent, ascorbic acid (AsA) in the transgenic plants than in the wild-types. After methanol exposure, GSH levels increased by 95 % and 72 % in the FrmA/BOE and FrmAOE plants, respectively, while showing no significant increase in the wild-type plants. The transgenic plants also maintained higher GSH:GSSG and AsA:DHA ratios, exhibited upregulated glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities, and correspondingly increased gene expression. In addition, the photosynthetic parameters of the transgenic plants were less affected by SOC stress, which represents a significant photosynthetic advantage. These results emphasize the potential of genetically engineered plants for phytoremediation and crop improvement, as they exhibit increased tolerance to multiple hazardous SOCs. This research lays the foundation for sustainable approaches to combat pollution and improve plant resilience in the face of escalating environmental problems.

This study investigates the influence of wood pellet fly ash blended binder (WABB) on the mechanical properties of typical weathered granite soils (WS) under a field and laboratory tests. WABB, composed of 50 % wood pellet fly ash (WA), 30 % ground granulated blast furnace slag (GGBS), and 20% cement by dry mass, was applied at dosages of 200-400 kg/m3 to four soil columns were constructed at a field site deposited with WS. After 28 days, field tests, including coring, standard penetration tests (SPT), and permeability tests, revealed enhanced soil cementation and reduced permeability, indicating a denser soil matrix. Unconfined compressive tests (UCT) and free-free resonant column (FFRC) tests on field cores at 28 and 56 days, compared with laboratory specimens and previously published data, demonstrated strength gains 1.2-2.1 times higher due to field-induced stress. The presence of clay minerals influenced the WABB's interaction and microstructure development. Correlations between seismic waves, small-strain moduli, and strength were developed to monitor in-situ static and dynamic stiffness gain of WABB-stabilized weathered granite soils.

This paper presents a comprehensive study on the evolution of the small-strain shear modulus (G) of granular materials during hydrostatic compression, conventional triaxial, reduced triaxial, and p-constant triaxial tests using 3D discrete element method. Results from the hydrostatic compression tests indicate that G can be precisely estimated using Hardin's equation and that a linear correlation exists between a stress-normalized G and a function of mechanical coordination number and void ratio. During the triaxial tests, the specimen fabric, which refers to the contact network within the particle assembly, remains almost unchanged within a threshold range of stress ratio (SR). The disparity between measured G and predicted G, as per empirical equations, is less than 10% within this range. However, once this threshold range is exceeded, G experiences a significant SR effect, primarily due to considerable adjustments in the specimen's fabric. The study concludes that fabric information becomes crucial for accurate G prediction when SR threshold is exceeded. A stiffness-stress-fabric relationship spanning a wide range of SR is put forward by incorporating the influences of redistribution of contact forces, effective connectivity of fabric, and fabric anisotropy into the empirical equation.

The fine-grained gassy soils are prevalent in coastal regions worldwide. The inadequate knownledge of their mechanics, leads to engineering geological issues such as seabed landslides, amid marine and offshore advancements. Through a series of triaxial tests combined with bender elements, this study investigated the stress-strain behavior of fine-grained gassy soil with varying initial gas contents and pore water pressures, along with the variations in the small-strain shear modulus during shearing, thereby facilitating a better understanding of gassy soils mechanics in situ exploration. Our findings show the gassy soils at initial pore water pressure of 150 kPa resemble saturated soils in the stress-strain behaviors, but differ in small-strain moduli. A distinctive inflection point at 5% strain signifies peak pore pressure and valley shear modulus, precedes strength and strain peaks. Additionally, there is an unique power relationship between the small-strain modulus and the secant shear modulus during shearing.

Accurate determination of potassium ion (K+) concentration in fingertip blood, soil pore water, pipette solution, and sweat is crucial for performing biological analysis, evaluating soil nutrients levels, ensuring experimental precision, and monitoring electrolyte balance. However, current electrochemical K+ sensors often require large sample volumes and oversized reference electrodes, which limits their applicability for the aforementioned small-volume samples. In this paper, a K+ sensor integrated with a glass capillary and a spiral reference electrode was proposed for detecting K+ concentrations in small-volume samples. A K+-selective membrane (K+-ISM)/ reduced graphene oxide-coated acupuncture needle (working electrode) was spirally wrapped with a chitosangraphene/AgCl-modified Ag wire (reference electrode). This assembly was then inserted into a glass capillary, forming an anisotropic diffusion region of an annular cylindrical gap with width 410 mu m and height 20 mm. It was found that the capillary action of the glass capillary results in a raised liquid level of the sample inside it compared to that in the container, which promotes efficient contact between the small-volume sample and the K+ sensor. Besides, the formed anisotropic diffusion region limits the K+ diffusion from the bulk solution to the K+ISM, which leads to a larger potentiometric response of the K+-ISM. The glass capillary-assembled K+ sensor displays high performance, including a sensitivity 58.3 mV/dec, a linear range 10_ 5-10_ 1 M, and a detection limit 1.26 x 10_6 M. Moreover, it reliably determines K+ concentrations in artificial sweat of microliter volume. These results facilitate accurate detection of K+ concentration in fingertip blood, soil pore water, and pipette solution.

The deterioration of soft rocks caused by freeze-thaw (F-T) climatic cycles results in huge structural and financial loss for foundation systems placed on soft rocks prone to F-T actions. In this study, cementtreated sand (CTS) and natural soft shale were subjected to unconfined compression and splitting tensile strength tests for evaluation of unconfined compressive strength (UCS, qu), initial small-strain Young's modulus (Eo) using linear displacement transducers (LDT) up to a small strain of 0.001%, and secant elastic modulus (E50) using linear variable differential transducers (LVDTs) up to a large strain of 6% before and after reproduced laboratory weathering (RLW) cycles (-20 degrees C-110 degrees C). The results showed that eight F-T cycles caused a reduction in qu, E50 and Eo, which was 8.6, 15.1, and 14.5 times for the CTS, and 2.2, 3.5, and 5.3 times for the natural shale, respectively. The tensile strength of the CTS and natural rock samples exhibited a degradation of 5.4 times (after the 8th RLW cycle) and 2.7 times (after the 15th RLW cycle), respectively. Novel correlations have been developed to predict Eo (response) from the parameters quand E50 (predictors) using MATLAB software's curve fitter. The findings of this study will assist in the design of foundations in soft rocks subjected to freezing and thawing. The analysis of variance (ANOVA) indicated 95% confidence in data health for the design of retaining walls, building foundations, excavation in soft rock, large-diameter borehole stability, and transportation tunnels in rocks for an operational strain range of 0.1%-0.01% (using LVDT) and a reference strain of less than 0.001% (using LDT). (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

This paper presents a method to create rubber clumps without significant volume loss within the framework of the discrete-element method (DEM), enhancing the understanding of particle-scale stress transmission and small strain behavior of sand-rubber mixtures. Extensive calibrations were conducted, including the compressive response of individual pure rubber clumps, the small strain stiffness and the shear behavior of pure rubber specimens. These calibrations aimed to accurately capture the key characteristics of rubber materials, including their deformability. The calibrated model was then used to study the mechanics of sand-rubber mixtures. The simulation data indicated a higher coordination number for rubber clumps, a result of their greater deformability and significant sensitivity to stress levels in comparison with sand grains. The research has further demonstrated that the proportion of the overall stress transferred by the rubber remained below its volumetric content, highlighting its significant sensitivity to stress and density levels, which are characteristics not significant in sand particles. Additionally, the small strain stiffness values of sand-rubber mixtures decrease with increasing rubber contents, reflecting the negligible contributions of rubber materials on small-strain stiffness. This observation supports the validity of refined state variables that exclude rubber materials when characterizing the small-strain behavior of sand-rubber mixtures. While this research is fundamental, the data presented herein can be useful to engineers working on embedding waste materials such as granular rubber in engineered fill.

The Discrete Element Method (DEM) has been widely used to study the macro-micro behaviour of granular materials at large strains (>1%). However, investigations over a wider strain range are lacking. This study conducts DEM triaxial tests on specimens with different particle physical properties to examine their influence on macro-micro behaviour from small strains (below 1 %) to large strains. Small-strain behaviour is characterised by the maximum shear modulus, elastic range and stiffness degradation rate. Large-strain behaviour is analysed through the peak stress ratio, critical state stress ratio and void ratio. Then, the micro-mechanisms underlying these results are examined using the Stress-Force-Fabric (SFF) relationship, which links the (macro) stress ratio and (micro) anisotropy source. This study is the first to apply the SFF relationship to small strain behaviour. Results reveal the qualitative relationship between particle physical properties and macro-behaviour at different strains: increasing particle Young's modulus enhances the maximum shear modulus but accelerates stiffness degradation; increasing shearing and rolling friction significantly reduces the stiffness degradation at small strains and enhances strength and dilation at large strains. This study also highlights the limitation of the Hertz contact model in capturing both small-strain and large-strain behaviour quantitatively using a single set of parameters. Hence, modellers should calibrate model parameters based on whether their focus is on large-strain or small-strain behaviour. For micro-behaviour, the relative importance of anisotropy sources depends on strain level rather than particle physical properties. At small strains, the mechanical anisotropy source (both normal and tangential forces) primarily controls stiffness and its degradation. At large strains, material strength is influenced by both mechanical and geometrical anisotropy sources, with anisotropy from the normal force being the most significant, followed by contact normal, tangential forces, and branch vector.

This study evaluates DNA damage and multi-element exposure in populations from La Mojana, a region of North Colombia heavily impacted by artisanal and small-scale gold mining (ASGM). DNA damage markers from the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, including micronucleated binucleated cells (MNBN), nuclear buds (NBUDs) and nucleoplasmic bridges (NPB), were assessed in 71 exposed individuals and 37 unexposed participants. Exposed individuals had significantly higher MNBN frequencies (PR = 1.26, 95% CI: 1.02-1.57, p = 0.039). Principal Component Analysis (PCA) identified the Soil-Derived Mining-Associated Elements (PC1), including V, Fe, Al, Co, Ba, Se and Mn, as being strongly associated with high MNBN frequencies in the exposed population (PR = 10.45, 95% CI: 9.75-12.18, p < 0.001). GAMLSS modeling revealed non-linear effects of PC1, with greater increases in MNBN at higher concentrations, especially in exposed individuals. These results highlight the dual role of essential and toxic elements, with low concentrations being potentially protective but higher concentrations increasing genotoxicity. Women consistently exhibited higher MNBN frequencies than men, suggesting sex-specific susceptibilities. This study highlights the compounded risks of chronic metal exposure in mining-impacted regions and underscores the urgent need for targeted interventions to mitigate genotoxic risks in vulnerable populations.