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Faults in the rock mass of dam foundation are crucial in controlling dam deformation and stability. In particular, long‐term stability of dam foundation is an important factor for the safety of dam operations. The rock in the foundation of Dagangshan hydropower station is mostly granite, and there are many diabase dikes distributed in granite. Geological survey indicates that many faults exist along the interfaces between granite and diabase. Lots of diabase were metamorphosed to chlorites, which have very low strength. In order to investigate the deformation of faults in diabase dikes under long‐term loading, in situ shear creep tests were performed to estimate the creep performance of a fault. The shear creep displacement and the influence of displacement history of the specimen during multi‐level loading tests were measured and analyzed. The isochronous stress‐strain method was used to determine the long‐term strength of the fault in shear creep tests. Considering the instantaneous damage and strain softening, a new viscoelastic‐plastic softening creep model was proposed to describe the shear creep behavior of the fault. Comparisons confirmed that this creep model is capable of describing the shear creep behavior of the fault and the creep parameters were estimated accordingly using this model. [ABSTRACT FROM AUTHOR]

Summary: The smooth‐joint contact model based on distinct element method has been widely used to represent discontinuity in the simulation of fractured rock mass, but there is rare efficient guidance for the selection of proper parameters of smooth‐joint contact model, which is the basement for using this model properly. In this paper, the effect of smooth joint parameters on the macroscopic properties and failure mechanism of jointed rock under triaxial compression test is investigated. The numerical results reveal that the friction coefficient of smooth joint plays a dominant role in controlling mechanical behaviors. The stiffness of smooth joint has a relative small influence on the mechanical behaviors. Poisson ratio decreases with the reduction of normal stiffness but increases with the reduction of shear stiffness. The reduction of smooth joint strength, which is determined by normal strength, cohesion, and friction angle of smooth joint, contributes to the breakage of bonded smooth joint and ultimately decreases the strength of the specimen. We proposed a detailed calibration process for smooth‐joint contact model according to the relationship between smooth‐joint parameters and mechanical properties. By following this process, the numerical results are validated against corresponding experimental results and good agreement between them can be found in stress‐strain curves and failure modes of different joint orientations. Further analyses from the microperspective are performed by looking at transmission of contact force, the nature and distribution of microcracks, and the particle displacement to show the failure process and failure modes. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries have received extensive attention due to their high theoretical specific capacity and theoretical energy density. However, their commercialization is hindered by the shuttle effect caused by the dissolution of lithium polysulfide. To solve this problem, a method is proposed to improve the performance of Li-S batteries using Ti2N(Ti2NS2) with S-functional groups as the sulfur cathode host material. The calculation results show that due to the mutual attraction between Li and S atoms, Ti2NS2 has the moderate adsorption energies for Li2Sx species, which is more advantageous than Ti2NO2 and can effectively inhibit the shuttle effect. Therefore, Ti2NS2 is a potential cathode host material, which is helpful to improve the performance of Li-S batteries. This work provides a reference for the design of high-performance sulfur cathode materials. [ABSTRACT FROM AUTHOR]

This study aims to investigate size effects on the strength and cracking patterns of crystalline rocks with artificial flaws which are commonly used to represent rock masses. We used a grain-based model (GBM) in the discrete element method (DEM) to reproduce the mineral microstructure and performed uniaxial compression tests on geometrically-similar flawed rocks with specimen sizes varying from 0.5 to 3 times the laboratory standard specimen. The results show that GBM faithfully reproduces the strength and cracking processes observed in the experiments. The strength decreases and cracking patterns become less jagged as the sample size increases. The micro-mechanism for size effects is attributed to the increased likelihood of including more inter-grain cracking paths in larger specimens. Moreover, lower flaw inclination angles can increase these size effects. Because specimens with flatly-inclined flaws have a lower stress gradient on the flaw surface, resulting in a wider potential area for microcrack to initiate. This area can contain more options for inter-grain cracking paths in larger specimens, resulting in greater strength reduction. Hence, we observe more significant strength size effects. This research provides new insights into bridging the gap between experimental data obtained on the laboratory scale and their practical applications in field-scale scenarios. [ABSTRACT FROM AUTHOR]

The large uncertainties of electrochemical input parameters, along with their variation with chemical environment and time, can significantly affect the accuracy of simulations and oversimplify the nonuniform corrosion distribution over time. To bridge the gap, this study investigated the effects of chloride ion concentration, humidity, and concrete mix on the electrochemical parameters through a long-term experiment of natural corrosion. The results revealed that the logarithmic anodic and cathodic exchange current density are almost constant values of −4.80 and −5.49 , respectively. The cathodic equilibrium potential slightly fluctuates around 253 mV versus the saturated calomel electrode. The increase in chloride ion concentration above 0% generally leads to a reduction in the anodic Tafel slope, while the absolute cathodic Tafel slope remains almost constant when chloride ion concentration exceeds 1.214%. Due to the distinct controlling mechanisms of corrosion, the effects of chloride and water-to-cement ratio on the electrochemical parameters are susceptible to the humidity level of concrete. Interestingly, at 90% humidity, the corrosion potential may shift negatively for a lower water-to-cement ratio, resulting in a decrease in the anodic Tafel slope. Nevertheless, a lower corrosion rate can still be anticipated. Employing the Butler–Volmer equation and Nernst equation, semiempirical models were constructed by representing the effects of humidity with piecewise functions. The accuracy has been validated through experimental data from both this work and previous studies. The results and empirical models of this study provide reasonable electrochemical input parameters for simulation of nonuniform corrosion and the evolution over time. [ABSTRACT FROM AUTHOR]

With the increase of burial depth, complex geological conditions such as high in situ stress, high seepage pressure and weak faults bring many adverse effects to the construction of deep tunnels. Taking Xianglushan Tunnel of Yunnan Water Diversion Project as the engineering background, we conduct a three-dimensional geo-mechanical model test under hydro-mechanical coupling to investigate the excavation stability and the supporting control of a deep tunnel crossing a weak fault. The test results reveal that: (1) The fault has adverse effects on the distribution of physical fields. In the fault, the stress of the surrounding rock is in the plastic state; the displacement and seepage pressure are larger. Accordingly, the contact pressure and seepage pressure of the lining become larger. (2) The distribution of contact pressure and seepage pressure on the lining is uneven. The contact pressure of the lining at the vault and the bottom is generally larger than that at the hance. The largest seepage pressure appears at the bottom, while the smallest at the vault. (3) There is a coupling effect between the stress field and the seepage field in the surrounding rock. The stress field affects the seepage field by changing the deformation of the surrounding rock. The seepage field simultaneously acts to the stress field. Test results obtained in this study will provide an experimental basis for further theoretical studies and engineering designs. [ABSTRACT FROM AUTHOR]

PbAl3(PO4)2(OH,H2O)6, an important environmental mineral, is in-situ studied by synchrotron x-ray diffraction (XRD) and Raman scattering combined with diamond anvil cells (DACs) at pressures up to ∼11.0 GPa and room temperature. The XRD results indicate that plumbogummite does not undergo a phase transition between 0 GPa and 10.9 GPa. Moreover, the c axis is more compressible than the a axis, revealing its anisotropic behavior. The pressure-volume data are fitted to the third-order Birch-Murnaghan equation of state to yield the plumbogummite bulk modulus of 68(1) GPa and of 6.1. The [PO4]3− and [HPO4]2− Raman vibrational modes exhibit scale nearly linearly as a function of pressure. The [PO4]3− stretching modes are generally more sensitive to pressure than the bending modes. The Grüneisen parameters range from −0.07 to 1.19, with an arithmetic mean of approximately 0.39. [ABSTRACT FROM AUTHOR]

The δ-AlOOH can transport water into the deep mantle along cold subducting slab geotherm. We investigate the hydrogen-bond symmetrization behavior of δ-AlOOH under the relevant pressure-temperature condition of the lower mantle using ab initio molecular dynamics (MD). The static symmetrization pressure of 30.0 GPa can be reduced to 17.0 GPa at 300 K by finite-temperature (T) statistics, closer to the experimental observation of ∼10.0 GPa. The symmetrization pressure obtained by MD simulation is related to T by P (GPa) + 13.9 (GPa) = 0.01 (GPa/K) × T (K). We conclude that δ-AlOOH in the lower mantle exists with symmetric hydrogen bond from its birthplace, or someplace slightly deeper, to the core-mantle boundary (CMB) along cold subducting slab geotherm. The bulk modulus decreases with T and increases anomalously upon symmetrization:for δ-AlOOH with asymmetric hydrogen bond, andfor δ-AlOOH with symmetric hydrogen bond. Our results provide an important insight into the existent form and properties of δ-AlOOH in the lower mantle. [ABSTRACT FROM AUTHOR]

• Propose a novel elastic–plastic damage softening model. • Using ODE45 program, the numerical solution of displacement and stress is solve. • The elastic–plastic region and displacement of high sidewall cavern are obtained. • The mechanical mechanism of splitting failure is that the stress in oscillation. Owing to excavation-induced unloading, high sidewalls of underground powerhouse are often subjected to splitting failure, which produces many adverse effects to the construction of the cavern. To reveal the formation mechanism of splitting failure, we proposed a novel elastic–plastic damage softening model based on the strain gradient theory and the elastic–plastic damage theory. Using the ODE45 program in MATLAB, the numerical solution of the displacement and stress of circular cavern was solved based on the newly proposed elastoplastic damage model. We then adopted the complex function method and used the Schwarz-Christoffel integral formula to obtain the mapping function from the outer domain of high sidewall cavern to the outer domain of the unit circle. Finally, the elastic–plastic region and the displacement distribution of high sidewall cavern were obtained by mapping the obtained elastic–plastic solution of the circular cavern under the axisymmetric condition. The numerical analysis results were consistent with the previous geomechanical model test results. The results presented that the stress of high sidewall of an underground powerhouse exhibits an oscillating variation with alternating peaks and troughs, which is the mechanical mechanism of splitting failure. [ABSTRACT FROM AUTHOR]

The safety assessment of structural defects in operational shield tunnels is crucial for ensuring their serviceability and safe operation. This study developed a novel comprehensive evaluation method for tunnel safety assessment based on semi-supervised learning and a stacking ensemble algorithm. First, in the membership degree calculation of the multidimensional normal cloud model, the importance coefficients of the tunnel safety evaluation indicators were used instead of their weights to improve the cloud model. This allowed generating unlabeled samples with patterns consistent with those of the collected samples with structural defects. Three classifiers, namely, random forest, extra trees, and gradient boosting, were employed for semi-supervised learning. This process converted unlabeled samples into pseudo-labeled samples, expanded the structural defects database, and ultimately optimized the classifier performance. Subsequently, a stacking algorithm was used to integrate the three optimized classifiers. This resulted in the creation of three stacking models, each containing multiple metamodels. Finally, the optimal metamodels were selected based on accuracy, precision, recall, and F1 score for a voting scheme to determine the tunnel safety level. The developed evaluation method was applied to a real-world engineering project. The evaluation results demonstrated consistency with those obtained from actual field conditions, thus validating the reliability and rationality of the proposed method. [ABSTRACT FROM AUTHOR]

When the buried depth of underground engineering exceeds 1000 m, the deep surrounding rock will show typical nonlinear deformation characteristics due to the coupling effect of high in-situ stress, and high seepage pressure. The stress field of surrounding rock will change the distribution characteristics of seepage field, and in turn, the change of seepage field will affect the distribution of surrounding rock stress field, which is a process of mutual influence and interaction. Considering the variation of permeability coefficient of deep surrounding rock and non-Darcy flow movement of fluid, a fully coupled hydraulic-mechanical analytical model of deep tunnel was proposed based on Hoek-Brown criterion and effective stress principle, and the detailed application method of the model was also given. Through the triaxial compression test under hydro-mechanical coupling, the nonlinear softening model considering seepage pressure and permeability variation equation were established, which solved two key problems of the model. The corresponding numerical calculation program was compiled based on ABAQUS finite element platform, and the reliability of the calculation program was verified by comparing with the model test results. The influence of the thickness of the grouting layer, the permeability coefficient of the grouting layer, the number of drainage holes and the depth of drainage holes on tunnel surrounding rock seepage pressure and lining seepage pressure were calculated and analyzed, and the anti-seepage optimization design of Xianglushan tunnel was carried out. [ABSTRACT FROM AUTHOR]

An accurate understanding of how water can affect the time-dependent deformation is important to assess the long-term stability of geotechnical projects. Triaxial compression rheological tests with different water contents were carried out to investigate the effects of water content and stress level on the creep strain, creep rate, long-term strength, and creep failure mode. Our experiments show that the time-dependent characteristics of rock are gradually activated with the increase of water content and stress level. The water content and stress level greatly increase the instantaneous strain, creep strain, and the steady creep strain rate, however, shorten the time to dilatancy and the time to failure. The creep curves and the creep rate versus time curves of argillaceous siltstone in the accelerated creep stage show a trend of "brittle-to-ductile" transformation. A modified steady-state creep rate tangent method was proposed and the analysis proves that the long-term strength of the rock decreases continuously with increasing water content. With the increase of water content, the rock exhibits a regularization of the main fracture surface, a gradual decrease of the number of secondary cracks, and a gradual disappearance of the shear slip phenomenon as observed. Our explanation is that since the clay minerals of T3sn argillaceous siltstone are mainly kaolinite, the main softening mechanism of the rock at low water content (0 ~ 1.14%) is the lubricating effect of the bound water film. The softening mechanism of clay-rich siltstone at high water content (1.14–3.35%) is dominated by the hydraulic fracturing action of pore water and Rehbinder effect. Highlights: The triaxial compression creep properties of argillaceous siltstone with different water contents are exposed. A modified steady-state creep rate tangent method for the determination of the long-term strength of soft rocks such as argillaceous siltstone is proposed. The softening mechanism of clay-rich siltstone with different water contents is analyzed and revealed. [ABSTRACT FROM AUTHOR]

Induced seismicity associated with fluid injection into underground formations jeopardizes the sustainable utilization of the subsurface. Understanding the fault behavior is the key to successful management and mitigation of injection-induced seismic risks. As a fundamental approach, laboratory experiments have been extensively conducted to assist constraining the processes that lead to and sustain various injection-induced fault slip modes. Here, we present a state-of-the-art review on the emerging topic of injection-induced seismicity from the laboratory perspective. The basics of fault behavior, including fault strength and instability, are first briefly summarized, followed by the paradoxical stability analysis arising from the current theoretical framework. After the description of common laboratory methods and auxiliary techniques, we then comprehensively review the effects of fault properties, stress state, temperature, fluid physics, fluid chemistry and injection protocol on fault behavior with particular focus on the implications for injection-induced seismicity. We find that most of the shear tests are conducted under displacement-driven conditions, while the number of injection-driven shear tests is comparatively limited. The review shows that the previous work on displacement-driven rock friction and fault slip modes partially unravel the mystery of injection-induced fault behavior, and recent experimental studies on the injection-driven response of critically stressed faults provide complementary insights. Overall, laboratory experiments have substantially advanced especially our understanding of the roles of fault roughness, fault mineralogy, stress state, fluid viscosity, fluid induced mineral dissolution, and injection rate in injection-induced seismicity, which has been successfully used to interpret many field observations. However, there are still outstanding questions in this area, which could be addressed by future experimental studies, such as the feasibility of seismic-informed adaptive injection strategy for mitigating seismic risks, colder fluid injection into critically stressed faults under hydrothermal conditions, and fault friction evolution during cyclic injection spanning from undrained to drained conditions. • A critical review of lab experiments on fault behavior is presented. • Lab experiments have advanced our understanding of injection-induced seismicity. • Operational parameters could be adapted to mitigate injection-induced seismicity. • Some outstanding questions could be answered by performing dedicated lab experiments. [ABSTRACT FROM AUTHOR]

An unexpected CO 2 -induced dissolution of ZnO into ionic liquids was discovered. This process exhibited high dissolution speed and the dissociated mixture was applied as an efficient Zn-based catalytic system for the CO 2 -promoted hydration of propargylic alcohols under atmospheric pressure with broad substrate scope. Moreover, this system could be recycled and reused for at least 16 times with excellent yields continuously obtained, which is an unprecedented record for this reaction. Significantly, this system could employ waste pigments as the ZnO source and work even under flue gas atmosphere. In the mechanistic investigations, the interaction between ZnO, CO 2 and ionic liquids to give N-heterocyclic carbene/CO 2 adducts proved to be the key factor for this specific dissolution. These adducts were further identified to exhibit better reactivity than the normal CO 2 by experimental data and density functional theory (DFT) calculations, which might be responsible for the excellent performance of the abovementioned catalytic system. [Display omitted] • An unexpected CO 2 -induced dissolution of ZnO into ionic liquids is reported. • The dissolution constructs a Zn-catalytic system for hydration of propargyl alcohols. • ZnO pigments and flue gas can be applied as ZnO and CO 2 sources for the hydration. • This catalyst works under ambient pressure and reaches a new record of recyclability. • N-heterocyclic carbene/CO 2 adducts are the key factor for dissolution and catalysis. [ABSTRACT FROM AUTHOR]

The widely used clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease (Cas) system is thought to have evolved from IS200/IS605 transposons. TnpB proteins, encoded by one type of IS200/IS605 transposon, are considered to be the evolutionary ancestors of Cas12 nucleases, which have been engineered to function as RNA-guided DNA endonucleases for genome editing in bacteria and human cells. TnpB nucleases, which are smaller than Cas nucleases, have been engineered for use in genome editing in animal systems, but the feasibility of this approach in plants remained unknown. Here, we obtained stably transformed genome-edited mutants in rice ( Oryza sativa ) by adapting three recently identified TnpB genome editing vectors, encoding distinct TnpB nucleases (ISAam1, ISDra2, and ISYmu1), for use in plants, demonstrating that the hypercompact TnpB proteins can effectively edit plant genomes. ISDra2 and ISYmu1 precisely edited their target sequences, with no off-target mutations detected, showing that TnpB transposon nucleases are suitable for development into a new genome editing tool for plants. Future modifications improving the genome-editing efficiency of the TnpB system will facilitate plant functional studies and breeding programs., Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-024-00172-6., Competing Interests: Conflict of interestKang Duan, Haitao Chen, Yongqiang Wang, and Xuping Wang are listed as inventors on a patent application related to this work filed by the Sanjie Institute of Forage, Yangling 712100, China., (© The Author(s) 2024.)

Covalent probes coupled with chemical proteomics represent a powerful method for investigating small molecule and protein interactions. However, the creation of a reactive warhead within various ligands to form covalent probes has been a major obstacle. Herein, we report a convenient and robust process to assemble a unique electrophile, an α-acyloxyenamide, through a one-step late-stage coupling reaction. This procedure demonstrates remarkable tolerance towards other functional groups and facilitates ligand-directed labeling in proteins of interest. The reactive group has been successfully incorporated into a clinical drug targeting the EGFR L858R mutant, erlotinib, and a pan-kinase inhibitor. The resulting probes have been shown to be able to covalently engage a lysine residue proximal to the ATP-binding pocket of the EGFR L858R mutant. A series of active sites, and Mg 2+ , ATP-binding sites of kinases, such as K33 of CDK1, CDK2, CDK5 were detected. This is the first report of engaging these conserved catalytic lysine residues in kinases with covalent inhibition. Further application of this methodology to natural products has demonstrated its success in profiling ligandable conserved lysine residues in whole proteome. These findings offer insights for the development of new targeted covalent inhibitors (TCIs)., (© 2024. The Author(s).)

A Brønsted acid-catalyzed α-C(sp 3 )-H amination of cyclic amines using hydrazines as coupling partners has been reported. This methodology provides a unique protocol to the one-step assembly of tetrahydro[1,3,4]triazepines via [1,5]-hydride transfer-initiated C(sp 3 )-H amination. This reaction features mild conditions, good yields, and high atom economy.

In contrast to the individual and nonsocial organism view of bacteria, recent discoveries show that bacteria can communicate and exhibit population behaviour via a system known as quorum sensing. Some bacterial behaviour can only be initiated when the cell number reaches a certain level (Quorum sensing, QS). It is generally believed that quorum sensing is used to coordinate cooperative behaviours at the population level; however, many issues exist regarding the evolution or development of such a system. In the present paper, the evolutionary process of bacterial quorum-sensing systems is discussed based on recent events and progresses in this field. As quorum sensing systems are often affected by environ-mental factors, such as temperature, pH, and nutrient levels, it is hence proposed that the evolution of bacterial cooperation, such as the quorum sensing, is rather a dynamic and ever-changing process which is radically affected by environmental conditions, genetic exchanges, as well as by changes in microbial community. The dynamic transformation suggests the advantages of cheaters of the system might have been short-lasted and confined in certain conditions and diminish over a long run.

Objective: To observe the release kinetics of methotrexate-loaded calcium phosphate cement (MTX-CPC) implanted in vivo and histologically investigate its resorption and osteogenesis., Methods: MTX-CPC consisting of 1% methotrexate (MTX) (weight/weight) was pre-set and implanted into femoral muscles of 24 New Zealand rabbits. The in vivo MTX release kinetics was determined on the 1st, 2nd, 5th, 10th, 15th, 20th, 25th, and 30th post-implantation day. The local concentrations and the residual percentage of MTX were determined. Then the pre-set MTX-CPC was implanted into femoral condyle. Calcium phosphate cement (CPC) without MTX was used as a control. The femurs were harvested at the 1st day and the 1st, 3rd, and 6th month and examined by X ray. Then histomorphometric analyses including percentage of newly formed bone and amount of osteoblast and osteoclast were performed., Results: The MTX release kinetics in vivo confirmed that MTX-CPC was a monolithic matrix system, with a burst effect in the initial stage and a sudden drop thereafter. The local concentration of the released MTX was 0.372 μg/ml on the 30th post-implantation day; with a concentration higher than the effective concentration,the incorporated MTX was expected to be continuously released over the following 2-3 months. Both MTX-CPC and CPC showed good biodegradability and osteoconduction. Although the release of MTX had an inhibitory effect on osteogenesis, especially in the initial stage, the area of newly formed bone, the amount of osteoblasts, and the amount of osteoclasts were not significantly different between MTX-CPC group and CPC group on the 6th post-implantation month., Conclusions: MPX-CPC system is an effective drug delivery system. Both MTX-CPC and CPC has good biodegradability and osteoconduction. Therefore,MTX-CPC system can be an ideal material for filling defects and controlling local recurrence.

Aim: To investigate the effect of SP-TAT-Apoptin in inducing HepG2 cells apoptosis and the possible application on hepatocellular carcinoma gene therapy., Methods: Recombinant gene SP-TAT-Apoptin was amplified by PCR and cloned into the eukaryotic vector plenti6-V5-D-TOPO. After the recombinant plasmid was identified by restriction enzyme digestion analysis and DNA sequencing, CHO cells were stably transfected with SP-TAT-Apoptin gene and the culture supernatant was collected. Then the expression of the fusion protein was detected by RT-PCR and Western blot. HepG2 cells were co-cultured with the supernatant. At various times post co-culture, HepG2 cells were detected by FCM., Results: The secretory Tat-Apoptin has an additive bystander effect as an anti-cancer therapy in vitro. The recombinant Apoptin was able to be secreted from transfected cells and re-enter adjacent un-transfected HepG2 cells, it can induce HepG2 cells apoptosis and induce G0/G1 arrest., Conclusion: SP-TAT-Apoptin can induce HepG2 cell apoptosis and cell cycle G1 arrest.