Model Experiments Research Articles

Evaluation of Benzene Presence and Formation in Benzoyl Peroxide Drug Products

The potent carcinogen, benzene, is a known degradation product of benzoyl peroxide (BPO) and was recently reported to form when BPO drug products, used for acne and rosacea treatment, are incubated at body temperature and elevated temperatures expected during storage and transportation. This study provides evidence for a wide range of benzene concentrations (0.16 ppm to 35.30 ppm) detected by GC-MS in 111 over-the-counter BPO drug products tested and maintained at room temperature. A prescription encapsulated BPO drug product was stability tested at cold (2°C) and elevated temperature (50°C), resulting in no apparent benzene formation at 2°C, and high levels of benzene formation at 50°C, suggesting that encapsulation technology may not stabilize BPO drug products but cold storage may greatly reduce benzene formation. Face model experiments where BPO drug product was applied to PolyMethyl MethAcrylate (PMMA) photoprotection test skin plates and benzene was detected in surrounding air by SIFT-MS, showed detectable benzene through evaporation and substantial benzene formation when exposed to UV light at levels below peak sunlight. Results suggest that potential benzene exposure from formation during BPO drug product use poses significant risks independent of the starting benzene concentration.

A numerical study on the issue of Reynolds independence of flow and dispersion within isolated street canyons

Achieving Reynolds number independence is a prerequisite for conducting scale model experiments. This paper presents a numerical model of the two-dimensional isolated street canyon, utilizing the validated reliable k-epsilon turbulence model based on wind tunnel experimental data, to investigate the influence of approaching wind profiles (α) and windward building width (WB) on achieving Reynolds number independence in the isolated street canyon and compare these characteristics with those observed in urban street canyon. quantitative criteria, including revised relative change ratios (RRCs) ≤ 20% and dimensionless concentration relative difference (K_RD) ≤ 5%, were employed in conjunction with velocity, concentration contours, and streamlines to determine the corresponding critical Reynolds numbers. The results suggest that variations in approaching wind profiles primarily influence the flow field structure within the isolated street canyon after achieving Reynolds number independence, particularly impacting the scale of the counterclockwise vortex. However, these variations do not significantly alter the critical Reynolds number (Recrit) required for achieving Re-independence, which is estimated to be Recrit = 2.2×10⁴ for the isolated street canyon. Varying WB affects the formation of counterclockwise vortex within the isolated street canyon. A reduction in WB facilitates its formation and accelerates reaching Re-independence. The Recrit is found to be linearly proportional to WB variation. The flow field structure in urban street canyons remains relatively stable, with a recommended Recrit = 3.1×10⁴. When WB is 18 cm, the Recrit for the isolated street canyon aligns with that of the urban street canyon.

Tectorigenin Inhibits Glycolysis-induced Cell Growth and Proliferation by Modulating LncRNA CCAT2/miR-145 Pathway in Colorectal Cancer.

Colorectal cancer (CRC) places a heavy burden on global health. Tectorigenin (Tec) is a type of flavonoid-based compound obtained from the Chinese medical herb Leopard Lily Rhizome. It was found to exhibit remarkable anti-tumor properties in previous studies. However, the effect and molecular mechanisms of Tec in colorectal cancer have not been reported. The objective of this study was to explore the action of Tec in proliferation and glycolysis in CRC and the potential mechanism with regard to the long non-coding RNA (lncRNA) CCAT2/micro RNA-145(miR-145) pathway in vitro and in vivo . The anti-tumor effect of Tec in CRC was examined in cell and animal studies, applying Cell Counting Kit-8 (CCK-8) assay as well as xenograft model experiments. Assay kits were utilized to detect glucose consumption and lactate production in the supernatant of cells and animal serum. The expression of the glycolysis-related proteins was assessed by Western Blotting, and levels of lncRNA CCAT2 and miR-145 in CRC tissue specimens and cells were assessed by realtime quantitative PCR (RT-qPCR). Tec significantly suppressed cell glycolysis and proliferative rate in CRC cells. It could decrease lncRNA CCAT2 in CRC cells but increase the expression of miR-145. LncRNA CCAT2 overexpression or inhibition of miR-145 could abolish the inhibitive effects of Tec on the proliferation and glycolysis of CRC cells. The miR-145 mimic rescued the increased cell viability and glycolysis levels caused by lncRNA CCAT2 overexpression. Tec significantly inhibited the growth and glycolysis of CRC xenograft tumor. The expression of lncRNA CCAT2 decreased while the expression of miR-145 increased after Tec treatment in vivo. Tec can inhibit the proliferation and glycolysis of CRC cells through the lncRNA CCAT2/miR-145 axis. Altogether, the potential targets discovered in this research are of great significance for CRC treatment and new drug development.

Operator-independent assessment of bread spoilage profiles caused by Bacillaceae reveals a high degree of inter- and intraspecies heterogeneity

Ropy bread spoilage caused by aerobic spore-forming bacteria (ASF) is characterized by discoloration, sticky and stringy crumb degradation, and a fruity odor due to the release of volatile organic compounds (VOCs). Previous studies employing model experiments have demonstrated strain-specific spoilage potential. However, to gain a deeper understanding, it is essential to study rope spoilage within baked bread. This study aimed to objectively evaluate the effect of different ASF strains on bread quality. 82 strains were subjected to a comprehensive evaluation, including proteotypic and genotypic fingerprinting, and 13 were selected for further analysis, where ASF endospore-spiked dough samples were baked and incubated. Physical changes in crumb texture, discoloration, and VOC production were quantified using texture analysis, color measurements, and headspace solid-phase microextraction gas chromatography-mass spectrometry. The high intraspecies diversity was reflected in strain-specific variations in rope spoilage profiles. A significant reduction in crumb firmness and increased discoloration, as well as the development of high levels of relative acetoin, were associated with rope spoilage. While color measurements could not detect early-stage spoilage, changes in crumb texture and VOC development were detectable after 24 h of baking. Even low levels of contamination (10^1 spores/g) could cause potential spoilage detectable by texture analysis, although not visible to the naked eye. This study provides an unbiased framework for future research and may help develop early detection tools for improved bread spoilage management.

Does vote buying undermine confidence in ballot secrecy? Theory and experimental evidence

Abstract Why does vote buying persist under the secret ballot? We argue initiating vote-buying transactions allows politicians to undermine voter confidence in the secret ballot, and thus to induce voter compliance. Our analysis consists of three parts. First, we present evidence from a survey experiment in Mexico that shows receiving material goods from a candidate diminishes voter confidence in ballot integrity. Next, we introduce an informational theory of vote buying that explains this phenomenon. Specifically, we develop a model of vote buying as a signaling game, in which a voter who is ex ante uncertain about a politician's capacity to monitor voter behavior learns new information from the politician's actions. Finally, we test the key insights from the model in a lab experiment. Our results suggest that, under certain conditions, offering material goods to voters is sufficient to erode their confidence in ballot secrecy, making vote buying effective.

Study on detection of pesticide residues in tobacco based on hyperspectral imaging technology.

Tobacco is a critical economic crop, yet its cultivation heavily relies on chemical pesticides, posing health risks to consumers, therefore, monitoring pesticide residues in tobacco is conducive to ensuring food safety. However, most current research on pesticide residue detection in tobacco relies on traditional chemical methods, which cannot meet the requirements for real-time and rapid detection. This study introduces an advanced method that combines hyperspectral imaging (HSI) technology with machine learning algorithms. Firstly, a hyperspectral imager was used to obtain spectral data of tobacco samples, and a variety of spectral pre-processing technologies such as mean centralization (MC), trend correction (TC), and wavelet transform (WT), as well as feature extraction methods such as competitive adaptive reweighted sampling (CARS) and least angle regression (LAR) were used to process the spectral data, and then, grid search algorithm (GSA) is used to optimize the support sector machine (SVM). The optimized MC-LAR-SVM model achieved a pesticide classification accuracy of 84.1%, which was 9.5% higher than the original data model. The accuracy of the WT-TC-CARS-GSA-SVM model in the fenvalerate concentration classification experiment was as high as 91.8 %, and it also had excellent performance in other metrics. Compared with the model based on the original data, the accuracy, precision, recall, and F1-score are improved by 8.3 %, 8.2 %, 7.5 %, and 0.08, respectively. The results show that combining spectral preprocessing and feature extraction algorithms with machine learning models can significantly enhance the performance of pesticide residue detection models and provide robust, efficient, and accurate solutions for food safety monitoring. This study provides a new technical means for the detection of pesticide residues in tobacco, which is of great significance for improving the efficiency and accuracy of food safety detection.

Flow manipulation of a nematic liquid crystal in a Hele-Shaw cell with an electrically controlled viscous obstruction

The flow of a nematic liquid crystal in a Hele-Shaw cell with an electrically controlled viscous obstruction is investigated using both a theoretical model and physical experiments. The viscous obstruction is created by temporarily electrically altering the viscosity of the nematic in a region of the cell across which an electric field is applied. The theoretical model is validated experimentally for a circular cylindrical obstruction, demonstrating user-controlled flow manipulation of an anisotropic liquid within a heterogeneous single-phase microfluidic device.

Veillonella parvula acts as a pathobiont promoting the biofilm virulence and cariogenicity of Streptococcus mutans in adult severe caries.

Adult severe caries (ASC) brings severe oral dysfunction and treatment difficulties to patients, and yet no clear pathogenic mechanism for it has been found. This study is focused on the composition of dental plaque microbiome profiles in order to identify disease-relevant species and to investigate into their interactions with the S. mutans. Samples of dental plaque were collected for metagenomic analysis. The acidification, aciduricity, oxidative stress tolerance, and gtf (glucosyltransferase) gene expression of S. mutans cocultured with V. parvula which was identified as ASC-related dominant bacterium. The biofilm formation and extracellular exopolysaccharide (EPS) synthesis of dual-strain were analyzed with scanning electron microscopy (SEM), crystal violet (CV) staining, live/dead bacterial staining, and confocal laser scanning microscopy (CLSM). Furthermore, rodent model experiments were performed to validate the in vivo cariogenicity of the dual-species biofilm. The most significantly abundant taxon found associated with ASC was V. parvula. In vitro experiments found that V. parvula can effectively promote S. mutans mature biofilm formation with enhanced acid resistance, hydrogen peroxide detoxicity, and biofilm virulence. Rodent model experiments revealed that V. parvula was incapable of causing disease on its own, but it significantly heightened the biofilm virulence of S. mutans when being co-infected and augmented the progression, quantity, and severity of dental caries. Our findings demonstrated that V. parvula may act as a synergistic pathobiont to modulate the metabolic activity, spatial structure, and pathogenicity of biofilms of S. mutans in the context of ASC.IMPORTANCEAdult severe caries (ASC), as a special type of acute caries, is rarely reported and its worthiness of further study is still in dispute. Yet studies on the etiology of severe caries in adults have not found a clear pathogenic mechanism for it. Knowledge of the oral microbiota is important for the treatment of dental caries. We discovered that the interaction between V. parvula and S. mutans augments the severity of dental caries in vivo, suggesting V. parvula may act as a synergistic pathobiont exacerbating biofilm virulence of S. mutans in ASC. Our findings may improve the understanding of ASC pathogenesis and are likely to provide a basis for planning appropriate therapeutic strategies.

Evaluating the Efficacy of Bacteriophage Therapy against Multidrug-Resistant Klebsiella pneumoniae Infections

Multidrug-resistant (MDR) Klebsiella pneumoniae poses a significant challenge to conventional antibiotic treatments. This study aims to assess the efficacy of bacteriophage therapy against MDR Klebsiella pneumoniae through a combination of in vitro assays, animal model experiments, and clinical case reviews. Phages isolated from environmental samples demonstrated potent lytic activity against MDR strains. In vitro assays showed that phages significantly reduced bacterial counts at a multiplicity of infection (MOI) of 1 or higher. Animal model experiments revealed that phage therapy, particularly using a cocktail of multiple phages, markedly improved survival rates and reduced bacterial loads in infected tissues compared to saline controls and standard antibiotics. Clinical case reviews indicated that patients receiving phage therapy experienced high rates of bacterial clearance and clinical improvement. These findings support the potential of bacteriophage therapy as an effective alternative or adjunct to traditional antibiotics in managing MDR Klebsiella pneumoniae infections.

Preparation, Characterization, and Wound Healing Promotion of Hydrogels Containing Glucosyloxybenzyl 2-Isobutylmalates Extract from Bletilla striata (Thunb.) Reichb.f.

Plant-derived medicinal materials have significant potential and promising applications in wound healing and skin regeneration. This study aims to develop a plant-based extract hydrogel from Bletilla striata (Thunb.Reichb.f.), specifically a glucosyloxybenzyl 2-isobutylmalates extract (B), and characterize its potential effects on wound healing. We synthesized the hydrogel using carbomer (C), glycerol (G), and triethanolamine (T) as the matrix, incorporating B into the hydrogel base, and evaluated its physical and chemical properties. In vitro tests assessed the biocompatibility of the glucosyloxybenzyl 2-isobutylmalates-carbomer-glycerol-triethanolamine (B-CGT) hydrogel and its effects on cell proliferation, migration, and adhesion. Animal model experiments evaluated its potential to promote wound healing. The results showed that the prepared B-CGT hydrogel possessed a good three-dimensional network structure and stability, demonstrating significant free radical scavenging capacity in antioxidant tests. In cell experiments, the B-CGT hydrogel exhibited no potential cytotoxicity and showed good hemocompatibility and promotion of cell proliferation. Animal experiments indicated that wounds treated with the B-CGT hydrogel healed significantly faster, with improved formation of new epithelial tissue and collagen. This study suggests that the developed B-CGT hydrogel is a promising candidate for wound dressings, with excellent physicochemical properties and controlled drug release capabilities, effectively promoting the wound healing process.

Quantification of ocean microplastic fragmentation processes in the Sea of Japan using a combination of field observations and numerical particle tracking model experiments

This study estimated the fragmentation rate of microplastics (MiPs) in the Sea of Japan by analyzing MiP size over time following their generation from macroplastics (MaPs). A 5-year particle-tracking model was used to simulate the MaP and MiP motions driven by ocean currents, Stokes drift, the windage of MaPs, beaching, re-drifting, the conversion process from MaPs to MiPs, and the removal of MiPs from the upper ocean. MiP sizes decreased downstream in the Tsushima Current flowing northeastward. The highest correlation between MiP size and elapsed time occurred in the simulation where MiP fragmentation also occurred in the ocean, at 20 % of the rate on beaches. The apparent fragmentation rate in nature was estimated to approximately 1.0 mm/100 days. This study demonstrated that incorporating spatiotemporal information from the simulation into observed size results could further our understanding of fragmentation of MiPs degraded in marine environments.

Weakening characteristics of pile group foundations in clayey soil under vertical cyclic loading: Experimental and numerical investigation

Long-term cyclic loading can substantially reduce the bearing capacity of pile foundations, potentially compromising the structural integrity of offshore foundations. A small-scale model test system for vertical cyclic loading of pile foundations is independently designed. Model experiments and numerical simulations were conducted to investigate the weakening characteristics of four foundation types (i.e., slab foundation, single pile with cap, 2 × 2 pile group foundation, and 3 × 3 pile group foundation) in clayey soil under cyclic loading. The results of both methods demonstrate that 3 × 3 pile group foundations exhibit the greatest resistance to deformation, followed by 2 × 2 pile groups, single piles with a cap, and slab foundations under cyclic loading. Furthermore, a 3D numerical model was developed to simulate the real-world behavior of a pile group foundation for an offshore wind turbine. Results reveal that although the ultimate compressive bearing capacity decreases with higher cyclic loading levels, typical cyclic loads (0.1–0.2) encountered in practice do not greatly affect the long-term bearing capacity of the foundations. The proposed experimental and numerical simulation methods offer valuable insights into the weakening characteristics of pile group foundations under cyclic loading.

A New Approach for Phage Cocktail Design in the Example of Anti-Mastitis Solution.

The studies on phage therapy have shown an overall protective effect of phages in bacterial infections, thus providing an optimistic outlook on the future benefits of phage-based technologies for treating bacterial diseases. However, the therapeutic effect is highly affected by the proper composition of phage cocktails. The rational approach to the design of bacteriophage cocktails, which is the subject of this study, allowed for development of an effective anti-mastitis solution, composed of virulent bacteriophages acting on Escherichia coli and Staphylococcus aureus. Based on the in-depth bioinformatic characterization of bacteriophages and their in vitro evaluation, the cocktail of five phages against E. coli and three against S. aureus strains was composed. Its testing in the milk model experiment revealed a reduction in the number of S. aureus of 45% and 30% for E. coli strains, and in the study of biofilm prevention, it demonstrated 99% inhibition of biofilm formation for all tested S. aureus strains and a minimum of 50% for 50% of E. coli strains. Such insights justify the need for rational design of cocktails for phage therapy and indicate the potential of the developed cocktail in the treatment of diseased animals, but this requires further investigations to evaluate its in vivo efficacy.

Wave overtopping discharges at rubble mound structures in shallow water

Wave overtopping of coastal structures has been studied using physical model experiments with rubble mound breakwaters in shallow water. The mean overtopping discharge is determined for three different foreshore slopes and various hydrodynamic conditions. The hydrodynamic results confirm that energy is transferred to low-frequency waves in very shallow water and that the short waves are in phase with the lower-frequency waves in very shallow water. As a result, the extreme waves (e.g. 2% exceedance wave height) become relatively large in very shallow water due to the energy of the low-frequency waves affecting thereby the wave overtopping. To estimate the amount of energy at the low-frequency waves, an expression is derived which reasonably accurately predicts the low-frequency wave energy (RMSE of 0.06). Considering the non-dimensional overtopping discharge, the existing formulations for the non-dimensional mean wave overtopping discharge perform poorly to reasonably in shallow water with RMSLE ranging from 1.04 to 2.92. A parameter sensitivity study shows that the short-wave steepness, relative crest height and the low-frequency wave height are the most important parameters when predicting the mean overtopping discharge in shallow water. When including the short-wave steepness and relative crest height in an empirical formulation the RMSLE for the current dataset reduces to 0.69. A further increase in accuracy is found when the low-frequency wave height and 2% exceedance wave height are included (RMSLE 0.64).

Research on Stay Cable Tension Estimation Based on Vision-Based Monitoring System

The cables in cable-stayed bridges are the primary load-bearing components, making the accurate monitoring of cable tension crucial for assessing the service reliability of the cables and the overall safety of the bridge. This study presents the development of a non-contact, vision-based monitoring system utilizing computer vision technology for monitoring cable tension in cable-stayed bridges. The monitoring system comprises an industrial camera equipped with an infrared filter and an infrared target lamp, employing a sub-pixel template matching algorithm to achieve high-precision cable tension measurement under long-distance and multi-frequency motion conditions. Model experiments were conducted to validate the accuracy and stability of the vision-based monitoring system. Results from long-distance model experiments indicate that the system can accurately measure frequencies across various distances, with a maximum frequency error of only 0.05%. Additionally, results from multi-frequency model experiments demonstrate that the system can accurately measure multiple vibration frequencies, with a maximum frequency error of just 0.4%.

An investigation on seismic performance of the separated fluid inerter base on model experiment and shaking table test

Fluid inerters have gained attention in structural vibration control for their simplicity, durability, high energy dissipation, and significant apparent mass amplification. This study presents an innovative design of a separated fluid inerter, which enhances inertial force, allows for more flexible installation methods, and supports a wider range of connections. A mechanical model is developed and experimentally validated for the separated fluid inerter. The effects of key design parameters on the device's mechanical properties are examined, with a focus on the radii (r1) and length (l) of the helical tube and the radii (r2) of hydraulic cylinder. Theoretical and experimental results confirm the model's reliability and the sensitivity of the device to these parameters. Additionally, a combination of the separated fluid inerter with anti-overturning rolling isolation is applied to a frame structure, and its seismic performance is evaluated through the shaking table test. The results indicate that the separated fluid inerter can effectively reduce the displacement of the isolation layer without significantly increasing the top floor acceleration of the frame structure equipped base isolation (FS-BI).

Experimental and numerical investigation of wave loads on land-based multi-chamber OWC converters

Capturing more wave energy in a cost-effective principle has become a challenging task. Multi-chamber oscillating water column (OWC) devices are gradually gaining favour due to their potentially efficient characteristics. However, there is relatively limited research on dynamic analysis which is crucial for the safety and survival of multi-chamber OWC devices. In the study, model experiments of the hydrodynamic pressures for single-, dual- and three-chamber devices were conducted at a wave flume. A two-dimensional fully nonlinear numerical model for the interaction between waves and the OWC devices was established based on the higher-order boundary element method. The numerical results well cross-validated the experimental data. The wave forces and moments exerted on the devices were numerically calculated. The results indicate that the multi-chamber configurations not only generally reduce the wave loads on front and rear walls in high-frequency waves, but also avoid the sloshing motion of the water column inside the chamber, which induces large wave loads on the converter. However, the additional internal walls impose a redoubled burden on the junction of the top ceiling and the rear wall. The OWC converters sustain the horizontal forces much more than vertical forces. The front lip (i.e., the bottom edge of the front wall), the rear wall and the connection between the seabed and the device are relatively dangerous positions for configurations with any number of chambers.

The influence of steep faults at various avoidance distances on the stability of hard rock caverns: Physical model experiments and DEM simulations

The influence of avoidance distances from steep faults on the stability of hard rock caverns is pivotal in deep engineering, yet research in this area remains scant. This study constructed 10 physical models of granite caverns, incorporating artificial cement-filled faults at various avoidance distances ranging from 0 to 2.4 cavern diameters. Biaxial compression experiments were conducted, utilizing acoustic emission and digital image correlation techniques for monitoring. Coupled with discrete element method simulations, the analysis explored the influence mechanisms of fault-cavern distance on the failure modes of hard rock caverns. The results reveal a positive correlation between the peak strength of specimens and fault-cavern distance. As the distance approaches 0.6 cavern diameters, the fault significantly influences the displacement field, crack number, distribution, and crack initiation location within the specimens. Furthermore, even at 1.2 cavern diameters, the fault still exhibits a notable influence on the stress field, external load transfer paths, cavern failure modes, and the size distribution of spalling debris. These findings can guide the selection of sites for deep hard rock caverns, ensuring a minimum fault-cavern distance of 1.2 cavern diameters to mitigate the risks posed by steep faults to such caverns.

Irrotational Flow over Ogee Spillway Crest: New Solution Method and Flow Geometry Analysis

A spillway is a hydraulic structure of major importance in dam safety, and its current analysis usually involves a hybrid approach combining CFD modeling with experimental research, either using well-known WES design charts or conducting new model experiments in the laboratory. Flow over spillway crests involves fluid accelerations, making irrotationality an adequate simplification of the Navier–Stokes (NS) equations. However, an efficient tool using this method is currently lacking for spillway flow, particularly for ogee spillway flow. This work focuses on this aspect of the problem, and a new method for computing irrotational flow solutions over ogee spillways is proposed by developing flow net computational solutions. The proposed method entails a new iterative procedure in the complex potential plane where free surface pressures are exactly set to zero, contrary to other methods, and an automatic determination of the critical point, the unknown energy head, and the free surface profile. The model generates solutions efficiently in only a few seconds on a personal workstation, permitting a fast estimate of spillway flow operation, and is thus an effective complement to experimental and NS-CFD modeling. The solutions produced are compared with observations of a high operational head equal to five times the design head of the ogee crest, resulting in reasonable agreement. The application of the new model to investigate the limitations of analytical equations used in spillway flow, like Jaeger’s theory, establishes limits for its use by relating its curvature parameter to the spillway chute slope.

Effects of water limitation and competition on tree carbon allocation in an Earth system modelling framework

Abstract Earth system models (ESMs) have a limited capacity to represent plant functional diversity and shifts in trait distributions. Approaches to improving the representation of this complexity in ESMs include (i) optimality‐based approaches that predict trait–environment responses and (ii) explicitly modelling coexistence and community assembly. These approaches are expected to converge only when optimality‐based approaches identify competitively dominant strategies, which often differ from strategies that maximize ecosystem functioning or fitness components in monoculture. We used two models, LM3‐PPA (a vegetation demographic model designed as an ESM component) and BiomeE (a computationally efficient analog for LM3‐PPA), to explore how water limitation affects carbon allocation strategies of canopy trees. We compared competitive allocation strategies and those that maximize biomass or productivity in monoculture. We did not explicitly model coexistence or community assembly. Rather, we used model experiments to identify competitive and maximizing strategies in a two‐dimensional trait space under different precipitation and mortality scenarios. At 10 eastern US locations, we simulated historical, wet and dry climate scenarios, novel drought and three different mortality scenarios (low, medium or high sensitivity to water deficit). For each site and scenario, we identified the competitive strategy and three maximizing strategies (maximum biomass, productivity or drought‐tolerance). Root: leaf ratios tended to increase and leaf area tended to decrease with increasing water stress (increasing water limitation and its effects on mortality). However, relative to maximizing strategies, competitive strategies shifted towards greater allocation to roots and leaves with increasing water stress. Competitive overinvestments (greater allocation to roots and leaves by competitive strategies compared with maximizing strategies) were robust across different modelling contexts, including vegetation parameter sets (Acer vs. Populus), models (LM3‐PPA vs. BiomeE) and uncalibrated vsersus calibrated BiomeE versions. Synthesis: The theoretical prediction that competitive and maximizing allocation strategies differ under water limitation is confirmed for a demographic model designed as an ESM component. Optimality‐based trait predictions can simplify representing trait diversity in ESMs but do not always correspond to competitive outcomes. Explicitly modelling coexistence and community assembly in ESMs is challenging but is likely the most general approach to representing trait diversity.