Stability Analysis Research Articles

Shikonin induces ferroptosis in osteosarcomas through the mitochondrial ROS-regulated HIF-1α/HO-1 axis

BackgroundThe most common malignant bone tumour is osteosarcoma, which has an unsatisfactory prognosis and unsatisfactory treatment. Ferroptosis shows promise as an effective OS therapy. A substance extracted from the Lithospermum erythrorhizon, Shikonin (SHK), inhibits a number of tumours, including ovarian, gastric, and lung cancers. However, whether SHK induces OS ferroptosis and its mechanisms are not clear. PurposeOur study is aimed at investigating whether SHK causes ferroptosis and elucidating its molecular mechanism. MethodsCell counting Kit-8, cell cycle and cell apoptosis assay were utilised to assess therapeutic effect of SHK against OS. Normal cells, including H9C2, AML-12 and HK-2, haematoxylin and eosin staining and mice serum biomarker tests were used to assess SHK biosafety. Malondialdehyde (MDA) levels, the glutathione (GSH)/oxidized glutathione (GSSG) ratio, reactive oxygen species (ROS), lipid peroxide (LPO), and intracellular Fe2+ detection, quantitative reverse transcription PCR (qRT-PCR), Western blotting (WB) and rescue experiments were employed to confirm whether SHK induced ferroptosis in OS cells. Molecular docking, cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay were used to evaluate the direct binding between SHK and hypoxia-inducible factor-1α (HIF-1α). Protein stability and degradation analysis, small RNA interference, flow cytometry, qRT-PCR, and WB were used to investigate the molecular mechanism of ferroptosis. In vivo xenografts of nude mouse was used to study the anti-OS effect of SHK. ResultsSHK significantly reduced OS cell viability and induced apoptosis and G2/M arrest. SHK increased intracellular levels of MDA, ROS, LPO, and Fe2+ while simultaneously reducing the GSH/GSSG ratio and GPX4 and SLC7A11 expression. CETSA and DARTS results demonstrated that SHK did not bind targetly to HIF-1α. Instead, mitochondrial ROS (MitoROS) promoted HIF-1α expression, resulting in HO-1 overexpression, excess Fe2+ production, ROS accumulation and GPX depletion, and ferroptosis. Furthermore, inhibition of MitoROS using Mito-TEMPO downregulated HIF-1α/HO-1 axis and mitigated the SHK-induced ferroptosis. In vivo, SHK effectively suppressed OS growth with favourable biosafety, confirming the molecular mechanism underlying SHK-induced ferroptosis in OS. ConclusionWe observe that HIF-1α/HO-1 axis is the crucial factor in SHK-induced OS ferroptosis. Importantly, we demonstrate that HIF-1α is indirectly regulated by MitoROS rather than SHK bound directly to HIF-1α. Our research suggest that SHK is a potential drug candidate for OS treatment and may help in identifying novel therapeutic targets for OS.

Novel energy exchange behaviors and mechanisms in nonlinear acoustic metamaterials with multiple nonlinear resonators

Wave-wave interactions in a nonlinear metamaterial or structure with two propagating waves can induce energy exchange within the nonlinear systems. The effects of nonlinear resonators on these interactions and energy exchanges in a nonlinear acoustic metamaterial have not been extensively studied in the literature. In this paper, a nonlinear monatomic acoustic metamaterial with multiple nonlinear resonators (NMAM-MNR) is constructed to investigate the new behaviors and mechanisms introduced by these nonlinear resonators. Stability analyses reveal that stability can be tuned by adjusting the number of nonlinear resonators and by selecting different intensities or masses of the resonators and the chain. Additionally, direct numerical simulations are performed to study the novel energy exchange behaviors and mechanisms in NMAM-MNR systems. The results demonstrate that the degree and frequency of energy exchange can be tuned by altering the mass ratios, stiffness ratios, intensities, and natural frequencies of the nonlinear resonators and the chain. The influence of mass and stiffness ratios on the time taken for the B-wave magnitude to first reach its maximum value in NMAM-MNR systems is also studied, showing that the rate of energy exchange induced by wave-wave interactions can be tuned by changing the stiffness and mass ratios of multiple nonlinear resonators. These properties have potential applications in the fields of energy harvesters, waveguides, and resonant energy transfer mechanisms.

Assessment stability and G x E interactions of baby corn hybrids for yield and yield contributing traits

The present study consisted of total 45 hybrids along with 18 parents and 2 checks. These entries were evaluated in randomized block design with three replications over three locations. Observations were recorded on ten characters to study per se performance, estimates genotype × environment interaction and stability parameters. The crosses × environment interactions were significant for all the characters indicating existence of non-linear response of crosses to the changing environments. The analysis of variance for individual environment indicated significant differences among genotypes for all the traits indicating the heritable nature of inheritance of these traits. The crosses EIQ-103 × EI-2156, EIQ-180 × EI-2518-4, and EIQ-103 × EI-670-2 were found to perform well across different environmental conditions for yield and yield-contributing traits. Specifically, the crosses EIQ-103 × EI-2156 and EI-1104-1 × EI-2156 demonstrated stability across various environments, while the crosses EI-2173 × EI-2156 and EIQ-235 × EI-2518-4 were particularly suitable for unfavourable conditions. Keywords: Baby Corn, Stability Analysis, Eberhart & Russell, G x E Interactions

Analytical and dynamical analysis of nonlinear Riemann wave equation in plasma systems

The Riemann wave equation presents appealing nonlinear equations applicable in sea-water and tsunami wave propagation, ion and magneto-sound waves in plasmas, electromagnetic waves in transmission lines, and homogeneous stationary media. This study focuses on deriving soliton solutions in optics and exploring their physical properties. A wave transformation is used to convert a partial differential equation into an ordinary differential equation, from which soliton solutions are obtained using the generalized Riccati equation mapping approach. The solutions encompass various types of solitons, including bright, dark, periodic, and kink solitons. A comparison of solutions from this analytical method enhances the understanding of the nonlinear model’s behavior, with implications in plasma physics, fluid dynamics, optics, and communication technology. Additionally, 2D and 3D graphs illustrate the physical phenomena of the solutions using appropriate constant parameters. The qualitative analysis of the undisturbed planar system involves examining phase portraits in bifurcation theory, followed by introducing an outward force to induce disruption and reveal chaotic phenomena. Chaotic trajectories in the perturbed system are detected through various plots, including 3D, 2D, power spectrum, and chaotic attractor, alongside Lyapunov exponents. Stability analysis under different initial conditions is conducted, and sensitivity assessments are performed using the Runge–Kutta method. The findings are innovative and have not been previously explored for this system, highlighting the reliability, simplicity, and effectiveness of these techniques in analyzing nonlinear models in mathematical physics and engineering.

ROCK SLOPE STABILITY ASSESSMENT WITH PROPOSAL OF GEOTECHNICAL SOLUTIONS FOR UNSTABLE PARTS

In recent years, the lack of construction land in attractive locations, especially in urban areas, has posed increasing challenges to designers and builders. That is why projects for the construction pit protection and ensuring the permanent slopes stability are increasingly present in geotechnical engineering. This paper presents a practical example from the initial phase of the commercial building construction in a rock cut at the entrance to Vrbnik, island of Krk. Due to the lack of construction space, and the floor plan placement of the building itself and accompanying contents, the construction project planned the implementation of an almost vertical rock slope in the background of the main object. To be able to propose a conceptual solution that would ensure the permanent stability of the mentioned rock slope, during the excavation phase of the construction pit (cut), a geodetic survey of the found condition and a geotechnical-geological prospecting of the rock mass were performed. The purpose of the investigation was to determine the condition of the slope, along with detecting the quality zones of the rock mass according to different engineering classifications, and with the aim of proposing techniques that need to protect certain parts of the slope. As proof of the permanent stability of the slope, for the established parameters of the rock mass and the proposed geometry and protection techniques, a stability analysis was carried out for characteristic cross-sections.

Identification of guar [Cyamopsis tetragonoloba (L.) Taub.] genotypes with wider adaptability to rainfed environments through stability analysis

The stability and yield of guar genotypes are important factors for the long-term development of this gum-producing industrial crop. A study was undertaken to assess the impact of the G × E interaction on yield stability in guar genotypes at seven distinct sites. Yield and its component traits such as the total number of pods per plant, pod length and seeds per pod were evaluated in the kharif season of 2020-21 and 2021-22 resulting in 14 environments. Stability tests for multivariate stability parameters were performed based on analyses of variance. For all the traits, the pooled analysis of variance revealed highly significant (p < 0.01) variations which provided sound evidence for the validity of the experiments. Genotypes KGG 6 and KGG 5 had desirable stability parameters for the number of pods per plant and pod length respectively. KGG 12 and KGG 3 were stable under all environments for number of seeds per pod. In the case of yield per hectare , the genotype KGG 6 recorded highest yield followed by KGG 4 and KGG 1. Among the tested genotypes, KGG 1 and KGG 2 were highly stable with average yield performance. AMMI biplots identified genotypes KGG 11 and KGG 12 as stable ones but these genotypes exhibited low-yield. The high-yielding stable genotypes identified in the present study could be recommended for commercial production in guar-growing areas of arid and semi-arid regions. Aside from these, the genotypes KGG 6 and KGG 4 were suited for exploiting better environmental conditions and genotype KGG 7 recorded more pod yield per plant and bi value less than one, explaining its suitability in poor environments. However, these genotypes could be incorporated into breeding strategy for yield enhancement in targeted environments. Keywords: Guar, Genotypes, Environments, G×E interaction, Stability.

Stability analysis on elite genotypes of Indian Mustard (Brassica Juncea L.) in Terai Agro-Climatic Region

Abstract Among the oilseed crops, mustard has gained precedence in the human diet due to its superior oil quality. Genotype × environment interactions have a significant effect on plant breeding because it reduces the stability of the genotypes in diverse environments. In order to assess the impact of environments on genotypes and determine the stable genotypes in terms of seed yield and yield attributing characters in the terai agro-climatic zone, seventy-one Indian mustard genotypes were evaluated during two consecutive years,namely, 2017-18 and 2018-19, focusing on nine quantitative characters across six environments. Eberhart and Russell model (1966) of stability analysis revealed that various genotypes exhibited adaptability to favourable and unfavourable environments for different characters, influenced by the different sowing dates over the two years. However, Rohini (SC) and KMR-15-14 to be well adapted in terai agro-climatic zone in respect to seed yield and plant height, while Pusa mustard 27 (EJ 17) were adapted to specifically favorable (rich) environment for the seed yield. In terms of secondary branches per plant and number of siliquae on branches, Pusa mustard 27 (EJ 17) showed adaptability across all types of environments. Therefore, Rohini (SC) and KMR-15-14 were identified as stable genotypes for optimum seed yield across different environmental conditions. Keyword: Mustard, G × E interaction, stability, , Regression, Deviation from regression, Brassica juncea

Unveiling Phenotypic and Environmental Dynamics: Exploring Genetic Stability and Adaptability of Faba Bean Cultivars in Norwegian Climates

ABSTRACTThis study evaluated 22 spring‐type faba bean cultivars in the main areas for cultivation of faba bean in Norway to assess the variation of 14 faba bean traits due to cultivar (G), environment (E), and their interaction (G × E), and to assess their stability across environments by using the additive main effects and multiplicative interaction (AMMI) analysis and coefficient of variation (CV). Significant G, E, and G × E effects were found for most traits, with environment accounting for much of the variance in yield and the growing degree days (GDD) to different developmental stages. Yield was highly correlated with thousand kernel weight (TKW) and GDD to BBCH 89 (maturation). The stability of the cultivars was studied for yield, TKW, and GDD to BBCH 89. Stability analysis using the AMMI stability value, yield stability index, CV, and the average sum of ranks identified Birgit, Stella, Bobas, and Macho as the most stable high‐yielding cultivars across environments, achieving a mean yield of 6–6.4 tons ha−1. Bobas, Macho, Stella, and Yukon had the most stable TKW (612–699 g) and Bobas, Capri, Trumpet, and Vertigo were the most stable regarding GDD to BBCH 89 (1257°C days, with a base temperature of 5°C). These stable cultivars can be utilized in breeding programs to achieve high and stable faba bean yield in the main growing areas of Norway and other Nordic‐Baltic countries.

Takagi-Sugeno fuzzy gain controller for Vehicle-to-Grid (V2G) load frequency control

Load Frequency Control (LFC) has gained more importance with the introduction of deregulated Renewable Energy Sources (RES) connectivity with the grid. Electrical Vehicles (EVs) can feed electricity back into the grid in Vehicle-to-Grid (V2G) mode to maintain stability. However, the increasing number of EVs penetrating the grid causes frequency instability in the power system. If required, EVs may utilize bi-directional chargers to transfer power back to the grid in the V2G mode while they are charging or in a grid-connected state, restoring the frequency instability of the grid. The frequency restoration response time is important to reset the grid frequency fluctuations in the shortest time possible to avoid shutting down the power system. This paper presents a Takagi-Sugeno (T-S) fuzzy linear output controller for LFC in two-area systems with tie-line control. This work models EV batteries as a single lump of large-capacity battery energy storage systems. The EV's battery system provides ancillary power to the two-area power system to reset it to a steady state after a load disturbance. The T-S fuzzy controller's linear output dependency on its inputs enables it to respond efficiently to load variations in the nonlinear two-area power systems. The proposed controller parameters are evaluated from stability analyses and its robustness is tested with sensitivity analysis. It is compared with other fuzzy controllers, and it demonstrates a fast-settling time and reduced frequency deviation response.

Sensitivity of flows over three-dimensional swept wings at low Reynolds number

High angle of attack flows over swept three-dimensional wings based on the NACA 0015 profile are studied numerically at low Reynolds numbers. Linear stability analysis is used to compute instability and receptivity of the flow via the respective three-dimensional (triglobal) direct and adjoint eigenmodes. The magnitude of the adjoint eigenvectors is used to identify regions of maximum flow receptivity to momentum forcing. It is found that such regions are located above the primary three-dimensional separation line, their spanwise position varying with wing sweep. The wavemaker region corresponding to the leading global eigenmode is computed and found to lie inside the laminar separation bubble (LSB) at the spanwise location of peak recirculation. Increasing the Reynolds number leads to the wavemaker becoming more compact in the spanwise direction, and concentrated in the top and bottom shear layers of the LSB. As sweep is introduced, the wavemaker moves towards the wing tip, following the spanwise displacement of maximum recirculation. Flow modifications resulting from application of different types of forcing are studied by direct numerical simulation initialised with insights gained from stability analysis. Periodic forcing at the regions of maximum receptivity to momentum forcing results in greater departure from the baseline case compared to same (low, linear) amplitude forcing applied elsewhere, underlining the potential of linear stability analysis to identify optimal regions for actuator positioning.

Far field operator splitting and completion in inverse medium scattering

Abstract We study scattering of time-harmonic plane waves by compactly supported inhomogeneous objects in a homogeneous background medium. The far field operator associated to a fixed scatterer describes multi-static remote observations of scattered fields corresponding to arbitrary superpositions of plane wave incident fields at a single frequency. In this work we consider far field operators for systems of two well-separated scattering objects, and we discuss the nonlinear inverse problem to recover the far field operators associated to each of these two scatterers individually. This is closely related to the question whether the two components of the scatterer can be distinguished by means of inverse medium scattering in a stable way. We also study the restoration of missing or inaccurate components of an observed far field operator and comment on the benefits of far field operator splitting in this context. Both problems are ill-posed without further assumptions, but we give sufficient conditions on the diameter of the supports of the scatterers, the distance between them, and the size of the missing or corrupted data component to guarantee stable recovery whenever sufficient a priori information on the location of the unknown scatterers is available. We provide algorithms, error estimates, a stability analysis, and we demonstrate our theoretical predictions by numerical examples.

Assessment of Aerotechnogenic Effects of Industrial Emissions of Arkhangelsk Pulp аnd Paper Mill by Bioindication Method

Assessment of the aerotechnogenic impact of the Arkhangelsk Pulp and Paper Mill on the environment was carried out. It is based on an analysis of the functional stability of representative bioindicator objects according to a set of biochemical parameters: enzymatic activity, content of phenolic compounds and ascorbic acid. The urbanized territory was mapped according to the degree of influence of the APPM on the components of forest ecosystems in accordance with the tendency of accumulation of sulfur compounds as marker pollutants of emissions of Pulp and Paper Mills. By the correlation analysis, it was shown that changes in the biochemical parameters of bioindicator objects are the manifestation of adaptive responses to the multifactorial effects of anthropogenic, technogenic and climatic impacts.

A Study on the Damage Evolution Law of Layered Rocks Based on Ultrasonic Waves Considering Initial Damage

The damage evolution process of layered rock is influenced by its fine structure, lamination direction, and confining pressure, exhibiting significant anisotropic characteristics. This study focuses on shale as the research object, employing indoor tests and theoretical analysis to define damage variables and initial damage based on ultrasonic wave velocity. This research investigates the damage evolution law of layered rock under varying confining pressures and dip angles. The findings reveal that damage variables defined using transverse wave velocity effectively reflect the damage evolution process. Additionally, confining pressure significantly affects damage evolution, with increasing pressure causing a rightward shift in the damage variable–strain curve and an increase in initial damage. The slab inclination angle also influences damage evolution; samples with 45° and 60° inclinations are more susceptible to damage, with initial damage showing a trend of increasing and then decreasing. To accurately describe the relationship between damage variables and strain during the loading process, this paper establishes a segmented damage evolution equation characterized by wave velocity. Initially, an inverse proportional function is employed to characterize the strain before crack closure. Subsequently, a logistic function represents the curve from crack strain to peak strain. This combined approach provides a comprehensive depiction of the damage evolution. This study underscores the importance of considering confining pressure and laminar inclination in the analysis of rock stability and integrity. These results provide critical insights into the damage evolution characteristics of layered rocks, offering valuable references for engineering safety assessments.

Dynamics of a non-local intraspecific competition predator–prey model with memory effect

In the paper, we investigate a diffusive predator–prey model with nonlocal intraspecific prey competition and spatial memory under Neumann boundary conditions. Through stability and bifurcation analysis, we find that the memory-based diffusion coefficient and the spatiotemporal diffusive delay have important effects on the dynamics of the model. By using the spatiotemporal diffusive delay as a bifurcation parameter, the critical values are determined for the stability of the positive constant steady state and the associated Hopf bifurcation. We find that the system may admit no stability switch, one stability switch and multiple stability switches.

Construction of Second-Order Finite Difference Schemes for Diffusion-Convection Problems of Multifractional Suspensions in Coastal Marine Systems

Introduction. This paper addresses an initial-boundary value problem for the transport of multifractional suspensions applied to coastal marine systems. This problem describes the processes of transport, deposition of suspension particles, and the transitions between its various fractions. To obtain monotonic finite difference schemes for diffusion-convection problems of suspensions, it is advisable to use schemes that satisfy the maximum principle. When constructing a finite difference scheme that adheres to the maximum principle, it is desirable to achieve second-order spatial accuracy for bothinterior and boundary points of the domain under study. Materials and Methods. This problem presents certain difficulties when considering the boundaries of the geometric domain, where boundary conditions of the second and third kinds are applied. In these cases, to maintain second-order approximation accuracy, an “extended” grid is introduced (a grid supplemented with fictitious nodes). The guidelineis the approximation of the given boundary conditions using the central difference formula, with the exclusion of the concentration function at the fictitious node from the resulting expressions. Results. Second-order accurate finite difference schemes for the diffusion-convection problem of multifractional suspensions in coastal marine systems are constructed. Discussion and Conclusion. The proposed schemes are not absolutely stable, and a detailed analysis of stability and convergence, particularly concerning the grid step ratio, remains an important problem that the author plans to address in the future.

GEOTECHNICAL CONDITIONS FOR THE WIDENING OF THE EXISTING EMBANKMENTS ON THE GOLUBOVCI-BAR RAILWAY SECTION, THE SECTION THROUGH SKADAR LAKE

The reconstruction of the existing embankments along the Golubovci-Bar railway line, particularly through the section that traverses Lake Skadar, represents a significant engineering challenge due to the location's specific characteristics and ecological restrictions. This area is a protected region, which limited the implementation of certain design solutions. Embankment stability analysis using the finite element methodndicated that the existing embankment does not meet the global safety factor requirements for design earthquake according to Eurocode 8. The paper presents the engineering-geological conditions of the existing embankments, as well as recommendations for their expansion and stabilization.

Transient synchronization stability mechanism of PMSG with additional inertia control

AbstractSynchronous stability is crucial for the safety and operation of AC power systems. However, most of the current researches focused on the stability of grid‐connected converters, and that of renewable equipment still lacked. In this article, the impact of the additional inertia control (AIC) on the permanent magnet synchronous generator (PMSG) is studied. It is found that with the AIC, the machine‐side converter dynamics of the PMSG cannot be ignored, and the system dominant dynamics shifts from the electromagnetic to electromechanical timescales. This article develops a simplified model for the single‐PMSG infinite‐bus system with the AIC within the electromechanical timescale, and reveals the transient synchronization stability mechanism from three aspects: the machine‐network interface, transient dominant variable, and interaction between the synchronization loop and the power imbalance loop. Finally, this article analyzes the swing characteristics of the PMSG system, and uncovers the relationship between the energy transmission and synchronization. These findings are supported by wide experimental verification and can provide the deeper physical insight and theoretical basis for the transient synchronous stability analysis of renewable‐dominated new‐type power systems.

Reformulation and Enhancement of Distributed Robust Optimization Framework Incorporating Decision-Adaptive Uncertainty Sets

Distributionally robust optimization (DRO) is an advanced framework within the realm of optimization theory that addresses scenarios where the underlying probability distribution governing the data is uncertain or ambiguous. In this paper, we introduce a novel class of DRO challenges where the probability distribution of random variables is contingent upon the decision variables, and the ambiguity set is defined through parameterization involving the mean and a covariance matrix, which also depend on the decision variables. This dependency makes DRO difficult to solve directly; therefore, first, we demonstrate that under the condition of a full-space support set, the original problem can be reduced to a second-order cone programming (SOCP) problem. Subsequently, we solve this second-order cone programming problem using a projection differential equation approach. Compared with the traditional methods, the differential equation method offers advantages in providing continuous and smooth solutions, offering inherent stability analysis, and possessing a rich mathematical toolbox, which make the differential equation a powerful and versatile tool for addressing complex optimization challenges.

Research and Evaluation of a Nanometer Plugging Agent for Shale Gas Horizontal Wells.

Due to the low permeability of shales, drilling fluid filtrate is very likely to intrude into the formation along the nanomicron pore joints of shale, leading to microfracture expansion and causing a well wall destabilization phenomenon. Based on the characteristics of the formation shale, a new nano plugging agent, styrene (St)/2-acrylamido-2-methylpropanesulfonic acid (AMPS)/ethyl acrylate (EA), was synthesized by emulsion polymerization using St, EA, and AMPS as reaction monomers. The analysis results using infrared spectroscopy and transmission electron microscopy showed that the product met the expected design. The particle size of the nano plugging agent St/AMPS/EA was mainly concentrated in the range of 50-130 nm. Thermogravimetric analysis revealed that the initial thermal decomposition temperature of St/AMPS/EA is 363.8 °C, indicating strong thermal stability. At a 3% concentration, the permeability of the mud cake decreased by 87.35%, and the maximum differential stress of the shale increased from 141.7 to 174.4 MPa. Stability analysis showed that the plugging agent maintained good plugging performance under various pH values and salinity conditions with fluid loss consistently around 3.2 mm. This nano plugging agent significantly improves wellbore stability, making it suitable for drilling in the Longmaxi Formation shale with developed microfractures, and provides valuable insights for similar formations.

MHD stability analysis against pressure and current-driven modes in the SMall Aspect Ratio Tokamak

Abstract Linear magnetohydrodynamic (MHD) simulations for the SMall Aspect Ratio Tokamak (SMART) have been carried out for the first time, for both positive (PT) and negative triangularity (NT) shaped plasmas using the MARS-F code. The MHD stability of projected SMART plasmas against internal kinks, infernal modes and edge peeling-ballooning modes have been analyzed for a wide range of realistic equilibria. A stabilization of internal kinks and infernal modes is observed when increasing the safety factor profile and reducing plasma beta. PT shaped plasmas are more stable against both internal kinks and infernal modes than their counterpart NT shaped plasmas. Toroidal flows have little impact on the MHD stability of the internal kinks, but they have a strong stabilizing effect on infernal modes, which can be further mitigated in NT shaped plasmas. The MHD stability of peeling-ballooning modes is reduced in NT shaped plasmas, as observed in conventional tokamaks.