Search Results (166)

Optimal Power Flow Operation (OPFO) is a large-scale, nonlinear, and highly constrained optimization problem that plays a central role in achieving economical, reliable, and environmentally sustainable power system operation. Despite the widespread use of metaheuristic algorithms for OPFO, many methods primarily depend on global-best updates or complex hybrid operators, leading to issues like premature convergence and diminished population diversity. Furthermore, recent literature tends to focus on numerical improvements without sufficiently addressing the underlying interaction structures that ensure stability in convergence. To address these limitations, this paper proposes an Improved Starfish Optimization (ISFO) algorithm incorporating a hybrid fitness-aware population-based search mechanism for solving OPFO problems involving the simultaneous regulation of synchronous generator outputs, on-load tap-changing transformer ratios, and reactive power compensation devices. The proposed method introduces an adaptive Fitness-Aware Collective (FAC) interaction strategy that systematically models pairwise fitness relationships to guide attraction toward superior solutions and repulsion from inferior ones, thereby strengthening exploitation while preserving diversity through controlled stochastic peer-based perturbations. A dual-mode search framework further balances global exploration and local intensification without introducing additional control parameters, enhancing robustness and scalability. The OPFO problem is formulated as a constrained nonlinear optimization model, where equality constraints enforce power flow balance equations and inequality constraints represent operational limits of generators, transformers, voltages, and transmission lines. The proposed ISFO is validated on the IEEE 57-bus power system under three operating scenarios: fuel cost minimization, transmission loss minimization, and emission minimization. Comparative results demonstrate consistent superiority over the standard Starfish Optimization Algorithm (SFOA). In cost minimization, ISFO reduces the total generation cost from 41,697.85 $/h to 41,669.34 $/h while simultaneously decreasing real power losses by 5.22%. Under loss minimization, ISFO achieves a minimum transmission loss of 10.77 MW, corresponding to a 9.23% reduction relative to SFOA, with improved convergence stability. For emission minimization, ISFO attains the lowest emission level of 1.474 ton/h, representing a 6.65% reduction compared to SFOA, alongside an additional 5.67% reduction in system losses. Statistical evaluations based on 30 independent runs further confirm the robustness and reliability of the proposed approach, demonstrating reduced variance, narrower confidence intervals, and statistically significant improvements across all investigated objectives. Full article

During the excavation process of the foundation pit, soil parameters evolve dynamically. In order to improve the accuracy of soil parameter selection in foundation pit engineering and achieve accurate deformation prediction, this paper proposes a displacement inverse analysis method that combines the enhanced starfish optimization algorithm (ESFOA) and the hybrid kernel least squares support vector machine (LSSVM). The ESFOA improves the global search capability and convergence accuracy of the starfish optimization algorithm (SFOA) by optimizing the initial population and introducing a hunting mechanism. On this basis, the ESFOA was used to optimize the RBF kernel function width ($\sigma$), polynomial kernel coefficient ($q$), regularization penalty coefficient ($c$), and kernel function mixing weight ($\lambda$) of the hybrid kernel LSSVM model. Samples were obtained through finite element simulation and orthogonal experiments, and the optimized ESFOA-LSSVM model was used to establish the nonlinear mapping relationship between the horizontal displacement of the foundation pit excavation enclosure and the soil parameters. The horizontal displacement monitoring data of the foundation pit retaining structure is used to invert the soil parameters and predict the deformation of the retaining structure under subsequent conditions. The results show that (1) compared with other algorithms, the ESFOA has good global search capabilities and convergence accuracy; (2) the ESFOA-LSSVM model is tested through test samples, and the model has good accuracy and feasibility; (3) the parameters obtained by the inversion can effectively improve the prediction accuracy of foundation pit deformation, and the prediction results are closer to the actual monitoring values. Full article

Triple-negative breast cancer (TNBC) represents significant therapeutic challenges due to its aggressive behavior, metabolic plasticity, and lack of targeted treatments, prompting investigation of biologically active triterpene glycosides from the starfish Solaster pacificus. This study evaluated the ability of pacificusoside D (SpD) to synergistically enhance the anticancer efficacy of the glycolytic inhibitor 2-deoxy-D-glucose (2-DG) in TNBC MDA-MB-231 cells by targeting mitochondrial oxidative phosphorylation (OXPHOS). Methods included metabolic profiling via glucose uptake, lactate, and glutamate Glo assays; IC₅₀ determination by MTS and trypan blue assays; colony formation evaluation using a soft agar assay; and molecular mechanism elucidation by Western blot, fluorescence microscopy and spectrometry, and flow cytometry analyses. Results demonstrated that MDA-MB-231 cells predominantly utilized glycolysis under basal conditions, shifting to OXPHOS with 2-DG (0.5 mM). IC₅₀ values were 8.0/8.4 mM for 2-DG and 0.3/0.25 μM for SpD after 24 h of cell treatment. SpD exhibited a significant decrease in the number of colonies in MDA-MB-231 cells and possessed synergistic anticancer effects with 2-DG. Mechanistically, SpD increased tumor suppressor VHL expression level, down-regulated expression level of electron transport chain enzymes, generated reactive oxygen species, induced mitochondrial dysfunction, and triggered Bax/Bak-mediated apoptosis. These findings highlighted the synergistic anticancer potential of SpD in combination with 2-DG in aggressive breast cancer, offering insights into improved clinical outcomes in the future. Full article

This paper proposes a Gudermannian function-based proportional–integral–derivative (G-PID) controller to enhance the transient performance of automatic voltage regulator (AVR) systems operating under highly dynamic conditions. By embedding the smooth and bounded nonlinear mapping of the Gudermannian function into the classical PID structure, the proposed controller improves adaptability to large signal variations while effectively suppressing overshoot. The controller parameters are optimally tuned using the starfish optimization algorithm (SFOA), which provides a robust balance between exploration and exploitation in nonlinear search spaces. Simulation results demonstrate that the SFOA-optimized G-PID controller achieves superior transient performance, with a rise time of 0.0551 s, zero overshoot, and a settling time of 0.0830 s. Comparative evaluations confirm that the proposed approach outperforms widely used optimization algorithms (particle swarm optimization, grey wolf optimizer, success history-based adaptive differential evolution with linear population size, and Kirchhoff’s law algorithm) and advanced AVR control schemes, including fractional-order and higher-order PID-based designs. These results indicate that the proposed SFOA optimized G-PID controller offers a computationally efficient and structurally simple solution for high-performance voltage regulation in modern power systems. Full article

Recently, we found that Lystar5 protein from coelomic cells of A. rubens starfish interacts with nicotinic acetylcholine receptors (nAChRs) and integrin α8-like protein. We hypothesized that Lystar5 mediates detachment of coelomic cells from the matrix and their migration. Skin wound healing in humans is based on keratinocytes migration and is regulated by nAChRs and integrins. Here, we revealed that Lystar5 stimulates migration of human skin HaCaT keratinocytes and peripheral blood monocytes. Using ELISA, we found that Lystar5 binds to the membrane fraction of coelomic cells with its loops I and II, which form an active site of Lystar5 and resemble its pro-migratory activity. In keratinocytes and monocytes, Lystar5 and the peptides mimicking its loops I and II bound with α3, α4, and β2 nAChR and α5, αV, and β1 integrin subunits, which form molecular complexes. In keratinocytes, Lystar5 and its mimetics promoted short-term E/N cadherin switch and upregulated expression of α5 and αV integrins, EGFR, and ICAM-1. In keratinocytes and monocytes, Lystar5 and its mimetics upregulated E-selectin secretion. The ability of Lystar5 and its mimetics to stimulate skin keratinocyte migration and immune cell infiltration may be considered promising for the development of new wound-healing agents. Full article

Recently, the installed generation capacity of wind energy has expanded significantly, and the doubly fed induction generator (DFIG) has gained a prominent position amongst wind generators owing to its superior performance. It is extremely vital to enhance the low-voltage ride-through (LVRT) capability for the wind turbine DFIG system because the DFIG is very sensitive to faults in the electrical grid. The major concept of LVRT is to keep the DFIG connected to the electrical grid in the case of an occurrence of grid voltage sags. The currents of rotor and DC-bus voltage rise during voltage dips, resulting in damage to the power electronic converters and the windings of the rotor. There are many protection approaches that deal with LVRT capability for the wind turbine DFIG system. A popular approach for DFIG protection is the crowbar technique. The resistance of the crowbar must be precisely chosen owing to its impact on both the currents of the rotor and DC-bus voltage, while also ensuring that the rotor speed does not exceed its maximum limit. Therefore, this paper aims to obtain the optimal values of crowbar resistance to minimize the crowbar energy losses and ensure stable DFIG operation during grid voltage dips. A recent optimization technique, the Starfish Optimization (SFO) algorithm, was used for cropping the optimal crowbar resistance for improving LVRT capability. To validate the accuracy of the results, the SFO results were compared to the well-known optimization algorithm, particle swarm optimizer (PSO). The performance of the wind turbine DFIG system was investigated by using Matlab/Simulink at a rated wind speed of 13 m/s. The results demonstrated that the increases in DC-link voltage and rotor speed were reduced by 42.5% and 45.8%, respectively. Full article

The Isles of Scilly are an archipelago of islands in the far southwest of the UK which contain numerous beds of wild bivalve molluscs which are recreationally harvested for local consumption. However, the islands have never previously been assessed for the presence of harmful algae and their shellfish toxin metabolites which can cause serious human health impacts. This study sought to address these knowledge gaps through the analysis of seawater and shellfish tissues for microalgae and toxins utilizing portable and lab-based microscopy, nanopore sequencing, chemical analysis and immunoassay kits. The study design was affected by the national COVID-19 lockdown which enforced implementation of citizen-led sampling and in-field microscopy. Microscopy and sequencing approaches led to the confirmation of multiple HAB species of concern, including those potentially responsible for production of neurotoxic and diarrhetic shellfish toxins. A portable microscope was successfully utilized in the field for recognition of microalgae and for early warning of potential shellfish toxicity events. Chemical analysis of cockle, clam and mussel samples confirmed the detection of paralytic, diarrhetic and amnesic shellfish toxins, with an unusual okadaic acid group toxin profile reaching a maximum toxicity of approximately half the regulatory limit as defined by EU law. The Sensoreal Alert Lateral Flow Assay was used to screen and highlight samples containing higher concentrations of DSP toxins. Furthermore, Tetrodotoxin was detected for the first time in the UK in cockle and grooved carpet shells. Multiple saxitoxin analogues were also detected in two echinoderm species, with this providing the first ever report of paralytic shellfish toxins in the spiny starfish, Marthasterias glacialis. The toxin profiles in the two species varied significantly with a dominance of GTX4 in Luidia ciliaris as opposed to a dominance of STX in Marthasterias glacialis. Overall, the study showed that a multi-method assessment of a previously unexplored region within the UK territory contained microalgae and toxins of concern to human health, and that a citizen-led programme could be instigated using portable microscopy and rapid toxin testing to assess the early warning for potentially harmful microalgae and toxins in the region, with confirmatory analysis being conducted to establish actual levels of risk for local consumers of seafood. Full article

To address the issues of false positives and missed detections commonly observed in traditional underwater seafood object detection algorithms, this paper proposes an improved detection method based on YOLOv5s. Specifically, we introduce a Spatial–Channel Synergistic Attention (SCSA) module after the Fast Spatial Pyramid Pooling layer in the backbone network. This module adopts a synergistic mechanism where the channel attention guides spatial localization, and the spatial attention feeds back to optimize channel weights, dynamically enhancing the unique features of aquatic targets (such as sea cucumber folds) while suppressing seawater background interference. In addition, we replace some C3 modules in YOLOv5s with our designed three-scale convolution dual-path variable-kernel module based on Pinwheel-shaped Convolution (C3k2-PSConv). This module strengthens the model’s ability to capture multi-dimensional features of aquatic targets, especially in the feature extraction of small-sized and occluded targets, reducing the false detection rate while ensuring the model’s lightweight property. The enhanced model is evaluated on the URPC dataset, which contains real-world underwater imagery of echinus, starfish, holothurian, and scallop. The experimental results show that compared with the baseline model YOLOv5s, while maintaining real-time inference speed, the proposed method in this paper increases the mean average precision (mAP) by 2.3% and reduces the number of parameters by approximately 2.4%, significantly improving the model’s operational efficiency. Full article

A modified Enzyme Action Optimizer (mEAO) is proposed to tune a Fractional-Order Proportional–Integral–Derivative (FOPID) controller for precise temperature regulation of a nonlinear continuous stirred tank reactor (CSTR). The nonlinear reactor model, adopted from a standard benchmark formulation widely used in CSTR control studies, is employed as the simulation reference. The tuning framework operates in a simulation-based manner, as the optimizer relies solely on the time-domain responses to evaluate a composite cost function combining overshoot, settling time, rise time, and steady-state error. Comparative simulations involving EAO, Starfish Optimization Algorithm (SFOA), Success History-based Adaptive Differential Evolution with Linear population size reduction (L-SHADE), and Particle Swarm Optimization (PSO) demonstrate that the proposed mEAO achieves the lowest cost value, the fastest convergence, and superior transient performance. Further comparisons with classical tuning methods, Rovira 2DOF-PID, Ziegler–Nichols PID, and Cohen–Coon PI, confirm improved tracking accuracy and smoother actuator behavior. Robustness analyses under varying set-points, feed-temperature disturbances, and measurement noise confirm stable temperature regulation without retuning. These findings demonstrate that the mEAO-based FOPID controller provides an efficient and reliable optimization framework for a nonlinear thermal-process control, with strong potential for future real-time and multi-reactor applications. Full article

Timely, concerted, and persistent culling (or manual removal) is required to effectively manage population irruptions of crown-of-thorns starfish (CoTS; Acanthaster spp.). However, there are concerns that handling and culling gravid starfish may induce spawning. This study explicitly tested the frequency and timing of spawning for Pacific CoTS (Acanthaster cf. solaris) injected with either bile salts (10 mL of 8 g·L⁻¹ Bile Salts No. 3) or vinegar (20 mL of 4% acetic acid, with 10 mL injected into each of two non-adjacent arms), up to 48 h after treatment, while also considering three distinct experimental controls (handling controls, injection controls, and spawning controls). This study showed that male CoTS often spawn within 24 h after different culling treatments. However, the incidence of spawning by male starfish injected with vinegar (70%) was nearly twice that of male starfish injected with bile salts (36.4%). In contrast, there were no instances of spawning by female CoTS following handling or injections of bile salts and vinegar. Variation in the incidence of spawning between culling treatments is largely attributable to differences in the rate of mortality, whereby CoTS injected with bile salts (n = 23) consistently died within 24 h and therefore had limited opportunity to spawn. Meanwhile, CoTS injected with vinegar generally died >24 h post-treatment, and many had not died even after 48 h. This suggests that, where available, bile salts (rather than vinegar) should be used when culling Acanthaster cf. solaris, especially during reproductive periods. However, sustained culling effort is still the most direct and effective way to suppress the local densities and reproductive capacity of CoTS. Full article

This study investigates the optimal operation of distribution systems incorporating Photovoltaic (PV) units, Electric Vehicle Charging Stations (EVCSs), and DSTATCOM devices using the Starfish Optimization Algorithm (SFOA). The main goal of the SFOA is to minimize a combined function that encompasses three key objectives: reducing system losses, increasing PV capacity, and enhancing EVCS power. By applying the SFOA within a multi-objective optimization framework, the optimal locations and sizes of PV units, EVCSs, and DSTATCOMs are identified to meet these objectives. This study analyzes and compares several case studies with different numbers of EVCSs, focusing on the operation of a modified 51-bus distribution system over 24 h. Results show that PV hosting energy increases to 21.73, 23.83, and 29.22 MWh for cases with 1, 2, and 3 EVCSs, respectively. EVCS energy also rises to 12.41, 19.50, and 37.23 MWh for the same cases. The corresponding optimized DSTATCOM reactive powers are 11.02, 12.02, and 13.74 MVarh. Throughout all cases, system constraints—such as voltage limits, utility current, and power flow equations—remain within acceptable ranges. The findings demonstrate the SFOA’s effectiveness in optimizing distribution systems with various devices, ensuring efficient operation and meeting all key objectives while adhering to system constraints. Full article

While the starfish species Asterias pectinifera (Ap) and Asterias amurensis (Aa) are considered ecological threats to marine environments and the fishing industry, recent studies have identified them as rich sources of highly water-soluble, non-toxic collagen peptides. Mitochondrial dysfunction is a key driver of cellular senescence and skin aging, yet the therapeutic potential of marine-derived extracts in modulating mitophagy remains largely unexplored. In this study, we investigated whether starfish-derived extracts could mitigate senescence-associated phenotypes in human dermal fibroblasts (HDFs) through the modulation of mitophagy. Treatment with Ap- or Aa-derived extracts led to reduced senescence-associated β-galactosidase (SA-β-gal) activity, decreased expression of matrix metalloproteinase-1 (MMP-1), and suppression of pro-inflammatory cytokines including interleukin-6 (IL-6) and interleukin-8 (IL-8). Ap- or Aa-derived extracts significantly increased mitophagy in HDFs stably expressing mitochondrial-targeted Keima (HDF-mtKeima), while knockdown of PINK1, the essential regulator of mitophagy, abolished the mitophagy-inducing effects of Ap- or Aa-treatment, indicating that Ap- or Aa-derived extracts activate PINK1/Parkin-dependent mitophagy pathways. Importantly, PINK1 knockdown reversed starfish-induced suppression of MMP-1 and p21, demonstrating its crucial role in regulating senescence-associated gene expression. Additionally, Ap or Aa treatments significantly reduced reactive oxygen species (ROS) accumulation, improved mitochondrial function, and enhanced both basal and maximal respiratory capacity in senescent HDFs. These findings highlight that extracts derived from starfish promote mitophagy through PINK1-dependent mechanisms, exhibiting significant anti-senescence effects in HDFs. This suggests their potential application in the development of novel cosmeceuticals with skin-protective and rejuvenating properties. Full article

With the increasing demand for precision in seismic exploration, high-resolution surveys and shallow-layer identification have become essential. This requires higher sampling frequencies during seismic data acquisition, which shortens seismic wavelengths and enables the capture of high-frequency signals to reveal finer subsurface structural details. However, the insufficient sampling rate of existing petroleum instruments prevents the effective capture of such high-frequency signals. To address this limitation, we employ high-frequency geophones together with high-density and high-frequency acquisition systems to collect the required data. Meanwhile, conventional processing methods such as Fourier transform-based time–frequency analysis are prone to phase instability caused by frequency interval selection. This instability hinders the accurate representation of subsurface structures and reduces the precision of shallow-layer phase identification. To overcome these challenges, this paper proposes a denoising method for high-sampling-rate seismic data based on Variational Mode Decomposition (VMD) optimized by the Starfish Optimization Algorithm (SFOA). The denoising results of simulated signals demonstrate that the proposed method effectively preserves the stability of noise-free regions while maintaining the integrity of peak signals. It significantly improves the signal-to-noise ratio (SNR) and normalized cross-correlation coefficient (NCC) while reducing the root mean square error (RMSE) and relative root mean square error (RRMSE). After denoising the surface mountain drilling-while-drilling signals, the resulting waveforms show a strong correspondence with the low-velocity zone interfaces, enabling clear differentiation of shallow stratigraphic distributions. Full article

Heliaster has long been considered to comprise seven nominal species of starfish distributed across the Eastern Pacific, from Baja California (Mexico) southward to central Chile. Along the southeastern Pacific coast, three taxa have been traditionally recognized: H. helianthus (Paita, northern Peru, to Concepción, central-southern Chile), H. polybrachius (Mexico to Perú), and H. canopus (Juan Fernández Archipelago and Desventuradas Islands). However, extensive morphological overlap among these forms has cast doubt on the validity of H. canopus, with some authors treating it as a synonym for H. helianthus. To clarify this ambiguity, we applied an integrative framework combining detailed morphometrics, phylogenetic inference from mitochondrial (COI) and nuclear (H3) markers, and two species delimitation approaches (bPTP and ASAP). Our sampling spanned Peru, continental Chile, and the oceanic islands of Juan Fernández and Desventuradas. Variation in ray number and relative arm length among H. helianthus, H. canopus, and H. polybrachius proved allometric, scaling strongly with body diameter rather than indicating discrete species boundaries. Molecular data show >95% sequence similarity across all nominal taxa and recover a single, well-supported clade; bPTP and ASAP likewise support one Heliaster lineage throughout the southeastern Pacific, corresponding to H. helianthus. Accordingly, we redescribe H. helianthus, designate a neotype from Quintay, Chile, and formally synonymize H. canopus and H. polybrachius under H. helianthus. Our results indicate that a single species spans the Eastern Pacific from Ecuador and Peru to central-southern Chile, including offshore islands, underscoring the value of integrative taxonomy for robust delimitation and accurate biodiversity assessments in marine invertebrates. Full article

Population irruptions of crown-of-thorns starfish (CoTS; Acanthaster spp.) represent a perennial threat to Indo-Pacific coral reefs, often causing extensive coral loss and contributing to reef degradation. Therefore, extensive efforts are being made to contain population irruptions of CoTS either by culling or removing individual starfish across large reef areas. However, the efficacy and effectiveness of these management strategies are inherently constrained by limited detectability, even among adult starfish. This study adds to the limited quantitative data on the detectability of CoTS based on two independent intensive experimental studies conducted on Australia’s Great Barrier Reef. During depletive sampling (where all CoTS detected were removed prior to re-surveying the same area) over 3 days at Lizard Island, a total of 96 (out of 132) CoTS were recorded during initial surveys, and the average detectability across 34 transects where CoTS were recorded was estimated to be 78.4% (±13.4 SE). Estimated detectability declined to 64.4% (±11.22 SE) on day 2, suggesting that the remaining CoTS were more cryptic. During mark–recapture studies at Rib Reef, the total sample population was estimated to comprise 411 individuals, of which 266 (64.7%) were sighted during initial (day-time) surveys, while 322 (78.3%) were sighted at night. Average detectability across all surveys was estimated to be 75.9% (±0.05 SE). Our findings reaffirm that the detectability of adult CoTS is limited, which will inherently constrain the effectiveness of culling and removal. Full article