Structure Conditions Research Articles

Social restructuring during harsh environmental conditions promotes cooperative behaviour in a songbird.

Cooperation may emerge from intrinsic factors such as social structure and extrinsic factors such as environmental conditions. Although these factors might reinforce or counteract each other, their interaction remains unexplored in animal populations. Studies on multilevel societies suggest a link between social structure, environmental conditions and individual investment in cooperative behaviours. These societies exhibit flexible social configurations, with stable groups that overlap and associate hierarchically. Structure can be seasonal, with upper-level units appearing only during specific seasons, and lower-level units persisting year-round. This offers an opportunity to investigate how cooperation relates to social structure and environmental conditions. Here, we study the seasonal multilevel society of superb fairy-wrens (Malurus cyaneus), observing individual responses to experimental playback of conspecific distress calls. Individuals engaged more in helping behaviour and less in aggressive/territorial song during the harsher non-breeding season compared to the breeding season. The increase in cooperation was greater for breeding group members than for members of the same community, the upper social unit, comprised of distinct breeding groups in association. Results suggest that the interaction between social structure and environmental conditions drives the seasonal switch in cooperation, supporting the hypothesis that multilevel societies can emerge to increase cooperation during harsh environmental conditions.

Regulating the bioactivity of non-glycosylated recombinant human bone morphogenetic protein-2 to enhance bone regeneration

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is the predominant growth factor that effectively induces osteogenic differentiation in orthopedic procedures. However, the bioactivity and stability of rhBMP-2 are intrinsically associated with its sequence, structure, and storage conditions. In this study, we successfully determined the amino acid sequence and protein secondary structure model of non-glycosylated rhBMP-2 expressed by an E. coli expression system through X-ray crystal structure analysis. Furthermore, we observed that acidic storage conditions enhanced the proliferative and osteoinductive activity of rhBMP-2. Although the osteogenic activity of non-glycosylated rhBMP-2 is relatively weaker compared to glycosylated rhBMP-2; however, this discrepancy can be mitigated by incorporating exogenous chaperone molecules. Overall, such information is crucial for rationalizing the design of stabilization methods and enhancing the bioactivity of rhBMP-2, which may also be applicable to other growth factors.

Carbon composites in the mitigation of micro and nanoplastics

Abstract The pervasive issue of micro and nanoplastics (MNPs) in the environment has escalated into a global concern, necessitating the exploration of innovative and efficient removal strategies. This review paper provides a comprehensive analysis of the application of carbon composites in mitigating MNPs, drawing upon a wide array of studies and technological advancements in the field. Carbon composites, known for their high surface area, porosity, and functional ability, offer a promising avenue for the adsorption, degradation, and removal of MNPs from various environmental matrices. We delve into the mechanisms underlying the interaction between carbon composites and MNPs, including physical adsorption, chemical binding, and photocatalytic degradation, highlighting the factors that influence these interactions, such as composite structure, surface chemistry, and environmental conditions. The review further categorizes carbon composites, such as activated carbon, carbon nanotubes, graphene, and biochar-based composites, examining their efficacy, limitations, and potential environmental impacts. A critical analysis of recent field and laboratory studies provides insights into these composites’ practical applications and performance in real-world scenarios. Additionally, we discuss the challenges and future directions for developing carbon composites, including scalability, regeneration, and the sustainable production of these materials. Carbon composites hold significant potential for efficient mitigation of MNPs, offering a viable solution to one of our time’s most pressing environmental challenges. However, further research is needed to optimize these materials for widespread application, enhancing their selectivity, capacity, and durability while minimizing unintended environmental consequences. This review aims to catalyze further investigation and innovation in the field, paving the way for developing more effective and sustainable technologies for mitigating micro and nanoplastics.

Distinct Longitudinal Brain White Matter Microstructure Changes and Associated Polygenic Risk of Common Psychiatric Disorders and Alzheimer’s Disease in the UK Biobank

BackgroundDuring the course of adulthood and aging, white matter (WM) structure and organization are characterized by slow degradation processes such as demyelination and shrinkage. An acceleration of such aging processes has been linked to the development of a range of diseases. Thus, an accurate description of healthy brain maturation, particularly in terms of WM features, is fundamental to the understanding of aging. MethodsWe used longitudinal diffusion magnetic resonance imaging to provide an overview of WM changes at different spatial and temporal scales in the UK Biobank (UKB) (n = 2678; agescan 1 = 62.38 ± 7.23 years; agescan 2 = 64.81 ± 7.1 years). To examine the genetic overlap between WM structure and common clinical conditions, we tested the associations between WM structure and polygenic risk scores for the most common neurodegenerative disorder, Alzheimer’s disease, and common psychiatric disorders (unipolar and bipolar depression, anxiety, obsessive-compulsive disorder, autism, schizophrenia, attention-deficit/hyperactivity disorder) in longitudinal (n = 2329) and cross-sectional (n = 31,056) UKB validation data. ResultsOur findings indicate spatially distributed WM changes across the brain, as well as distributed associations of polygenic risk scores with WM. Importantly, brain longitudinal changes reflected genetic risk for disorder development better than the utilized cross-sectional measures, with regional differences giving more specific insights into gene-brain change associations than global averages. ConclusionsWe extend recent findings by providing a detailed overview of WM microstructure degeneration on different spatial levels, helping to understand fundamental brain aging processes. Further longitudinal research is warranted to examine aging-related gene-brain associations.

The Utilization of Date Palm (Phoenix dactylifera) Leaf Fiber as a Main Component in Making an Improvised Water Filter

Access to clean and safe water is known to be an obstacle for many people globally, leading to the necessity of creating a water filtration method that is feasible and can be made even in rural and developing areas. This study aimed to make an Improvised Water Filter that is sustainable, cost-effective, and locally sourced, using Date Palm (Phoenix dactylifera) leaf fiber as a main component. The Date Palm leaf fibers were extracted by boiling, drying, and manual scraping. The study strived to investigate the capability of Date Palm leaf fibers alone to improve water quality by testing fungal presence through culturing, physical pollutants by utilizing a microscope, and pH level and salinity levels using a calibrated multitester. The research findings proved the effectiveness of the Improvised Water Filter specifically by reducing fungal colonies by 4.33 and 8.33 in saltwater and contaminated water respectively, eliminating the majority of the physical pollutants by 53.5 micrometers and by 256.3 micrometers, neutralizing the water pH levels by 0.60 and by 0.78, neutralizing the salinity levels by 149.67 ppm and by 338.33 ppm, and exhibiting reliable durability and functionality properties in terms of its structure and filtering media condition with a water flow rate of 1.1L/min and 1.02L/min, and a minimal reduction in the weight of the filtering media by 3.7g and by 3.3g in saltwater and contaminated water respectively. The Improvised Water Filter has effectively filtered and neutralized the water samples, improving the water quality. Future researchers are recommended to conduct comparative studies involving Date Palm (Phoenix dactylifera) and other natural materials, examining filtration capabilities and efficiency, material durability, and by further investigating other water quality indicators to create an improved product that can produce potable and safer water.

Influence of vegetation structure and climatic conditions on abundance of free-living Amblyomma ticks (Acari; Ixodidae) in a Costa Rican dry forest

Resumen. Diferencias entre hábitats y la variación en las condiciones ambientales son factores que frecuentemente afectan la abundancia en las poblaciones de muchos animales, y el efecto de esta variación puede afectar de manera diferente cada estadio del ciclo de vida de un animal. En este estudio se compara el efecto de diferentes hábitats y cambio en las condiciones ambientales (e.g., temperatura y precipitación) sobre la abundancia de larvas, ninfas y adultos de garrapatas duras (Amblyomma spp.) en un bosque seco tropical. La abundancia de larvas fue alta en todos los hábitats, pero las ninfas y adultas fueron más abundantes en aquellos sitios más boscosos (mayor cobertura forestal). Los sitios boscosos posiblemente proporcionan condiciones más adecuadas para la sobrevivencia de los tres estadios de las garrapatas (larvas, ninfas y adultas) durante los periodos de búsqueda de huéspedes. Se encontró también que el pico de abundancia de los tres estadios ocurrió durante o cerca de la estación seca. Esto sugiere que las garrapatas tienen un pico reproductivo asociado con la estación seca, pero solamente la abundancia de ninfas se correlacionó con la variación en las condiciones ambientales.

Continuous and controllable synthesis of MnO2 adsorbents for H2S removal at low temperature

H2S is an extremely noxious impurity generated from nature and chemical industrial processes. High performing H2S adsorbents are required for chemical industry and environmental engineering. Herein, α-, γ-, and δ-MnO2 adsorbents with high sulfur capacity were synthesized through a continuous-flow approach with a microreactor system, achieving much higher efficiency than hydrothermal methods. The relationship between crystal structure and synthesis conditions such as residence time, reaction temperature, concentration of K+ in solution and reactant ratio is discussed. According to the H2S breakthrough tests at 150 °C, continuously prepared α-, γ-, and δ-MnO2 exhibited sulfur capacities of 669.5, 193.8 and 607.6 mg S/g sorbent, respectively, which was at a high level among the reported adsorbents. Such enhanced performance is related to the large surface area and mesopore volume, high reducibility, and a large number of oxygen species with high reactivity and mobility. Manganese sulfide and elemental sulfur were formed after desulfurization, which indicated the reaction consisted of two steps: redox and sulfidation of the sorbents. This study provides an innovative design strategy for the construction of nanomaterials with high H2S adsorption performances.

Обзор върху антракнозата по фасула (Colletotrichum lindemuthianum) в Бъргария

Bean anthracnose, caused by Colletotrichum lindemuthianum, is a key disease in a number of countries around the world. Depending on the varietal structure and climatic conditions, yield losses vary from 10-58% to the complete destruction of crops. For the conditions of Bulgaria, the disease has a sporadic character in the plain areas, but in the mountainous areas it occurs annually. The pathogen control is related to uninfected seed material, long crop rotation, destruction of plant residues, application of fungicides and use of resistant varieties. C. lindemuthianum is characterized by considerable virulence diversity, which makes it difficult to breeding resistant cultivars and leads to overcoming already achieved resistance. This publication summarizes research on the virulence diversity of C. lindemuthianum in Bulgaria over the last forty years. In parallel, data on the resistance of Bulgarian dry bean varieties, some of which are essential for production in the country, to a set of physiological races of C. lindemuthianum are summarized. The analysis of the identified races shows significant virulence diversity in the pathogenic populations in Bulgaria. During the period 1979-2006, 10 physiological races were identified - 2, 3, 6, 22, 23, 54, 73, 79, 81 and 131. Race 81 was dominantly prevalent (78.4% of isolates) in traditional dry bean growing areas in the country. Races 2, 6, 22, 54 and 131 are established in the Rhodopе Mountains and Pirin Mountains. Races 3, 23, 73 and 79 were incidental to Bulgaria and there is no confirmation of their distribution. Of the 17 varieties presented in the overview, resistance to 11 races of C. lindemuthianum has variety Pukliv 1. Variety GTB Blyan is susceptible to races 6 and 81 and resistant to the remaining 9 physiological races included in the test. The Pirina variety is resistant to 10 of the 11 races tested. The varieties Pukliv 1, Trakya and Pirina are resistant to race 81, which prevails in Bulgaria. All cultivars have resistance to one or more of the investigated physiological races, which makes it possible to include them as resistance donors in the breeding of dry beans, by the pyramidal accumulation of race-specific genes.

Palladium-catalyzed synthesis of low viscosity hyperbranched liquid polyethylene and its polar copolymers

In this investigation, we designed and synthesized a range of pyridine-imine Pd(II) complexes featuring 2-aryl and 6-diphenylmethyl substituents. These catalysts were specifically tailored for the preparation of hyperbranched polyethylene oils (HBPEOs) and polar-functionalized hyperbranched polyethylene oils (PFHBPEOs). The catalysts exhibited high activity in the synthesis of HBPEO, achieving rates as high as 2.97–17.67 × 104 g mol−1 h−1. The resulting products were characterized by low molecular weights ranging from 307 to 500 g/mol, high branching densities of 113–138/1000C, and correspondingly low viscosities. While demonstrating moderate activity in the range of 0.7–6.2 × 103 g mol−1 h−1 for the synthesis of PFHBPEO, the polar-functionalized hyperbranched polymers retained similar characteristics of low molecular weight (325–436 g/mol), high branching density (112–141/1000C), and low viscosity. Notably, the PFHBPEOs obtained through this process exhibited an exceptionally high insertion ratio (7.4–16.0 mol%) of MA, with the ester group positioned terminally on the long chain branching. NMR analysis further confirmed the presence of a diverse range of branching structures, with a significant proportion of hyperbranched motifs, in both HBPEO and PFHBPEO. Importantly, variations in the catalyst structure and polymerization conditions were found to significantly influence the activity, structural features, and properties of the resulting HBPEO and PFHBPEO.

Employing extended surfaces for a hybrid battery thermal management system comprising PCM and refrigerated cooling air: An experimental investigation

If electric vehicles (EVs) are to supersede a larger share of the automobile market, developing safer battery packs with longer life and larger energy and power capacities is crucial. An effective battery thermal management system (BTMS) can promise many critical attributes of an EV battery pack, such as safety, life, and reliability. This article presents an effective BTMS with a novel hybrid design in which phase change material (PCM) is hybridized with a refrigerated air stream equipped with fins. The presented hybrid design is investigated experimentally and the role of fin structure and environmental conditions are examined. In addition, active and passive cooling strategies are also investigated to provide a more comprehensive analysis. The results show that the pure passive BTMS cannot control the module temperature in hot environments. On the other hand, although an active BTMS incorporating the refrigerated air provides a fast cooling process, the maximum temperature difference exceeds the improper value of 15 °C. The results demonstrate that the hybrid BTMSs can effectively control the temperature as well as minimize the maximum temperature difference. Furthermore, employing fins in the hybrid BTMSs leads to faster cooling. Among the three investigated fin structures, the spiral structure shows the best performance in controlling the average temperature of the module with a 4.2 °C temperature reduction relative to a similar case with no fin. The results of this study show that in long-term operation, a hybrid cooling strategy requires about one-third less energy in comparison to an active cooling strategy.

Potential and limits using the DAD method for condition assessment of bridge structures

In the last years, the age of the bridge contingent is in all countries constantly increasing while in addition the bridges are solicited by an increased load level and an increased load frequency. This leads to an urgent need for defining efficient bridge structure condition assessment methods. Here, the Deformation Area Difference (DAD) method has already proven to be reliable and practicable. This has been shown in recent research in which it has been tested on real bridge structures using photogrammetry and compared with other highly precise measurement techniques. In order to further develop this method and to analyze the potential and limits of the DAD method in practical experiments, in the present study different parameters are varied such as e.g., the loading position along the longitudinal axis of the bridge structure, the damage position along the longitudinal axis of the bridge structure and the damage position in the cross-section. In addition, the method is analyzed on different bridge structure types. The results of the current study allow to determine set-ups for in-situ experimental investigations of existing bridge structures using the DAD method. A novel DAD Influence Line (DAD IL) is introduced to identify necessary load positions for the experiments. The Damage Detection Range depends on different damage levels, precisions, and deflection values. It is found that for local damage only one measurement line for the cross-section is not sufficient.

Reprogrammable Multi‐Responsiveness of Regenerated Silk for Versatile Soft Actuators

AbstractDeveloping stimulus‐responsive materials (SRMs) with reversible, large, and reprogrammable multi‐responsiveness is crucial for soft actuators and intelligent devices, which remains challenging. In this study, regenerated silk fibroin with hierarchical structure is utilized to specially design a reprogrammable multi‐stimuli‐responsive protein film and versatile soft actuators. The freestanding fibroin films exhibit notable thermal contraction (−1383 ppm K−1) and humidity‐responsiveness that can be repeatedly regulated by easy post‐treatment with Ca2+ as desired. The actuating and regulating mechanisms involve reversible conformational change that is magnified into macroscopic deformations by hierarchical structure, and the roles of material structure and ambient conditions in determining actuating performances are analyzed based on thermodynamics. Driven by humidity gradient, the fibroin film demonstrates spontaneous flipping locomotion, self‐oscillation with tunable frequencies, bio‐butterfly wing flapping, and transformation from 2D to 3D structure. Moreover, reprogrammable deformations at specific regions are achieved in multi‐stimuli‐driven PET/fibroin film actuators owing to the straightforward Ca2+‐content‐based tunability of the responsiveness. The fibroin‐based actuators can be used as artificial muscles to drive the high‐frequency wing‐flapping of a bio‐dragonfly and soft gripper to grasp, lift, and transfer objects. The simple yet effective strategy presented herein provides valuable inspiration for designing advanced SRMs and soft actuators with reprogrammable multi‐responsiveness.

Damage Identification of Full-Scale Steel Truss Structure Based on Model Condensation and Mean-Value Normalization Regularization Techniques

Structural health monitoring and damage identification aim to detect the internal damage and evaluate the health conditions of the practical engineering structure, which has been the most popular research field for several decades. The sensitivity-based method incorporated with the regularization techniques is the classical and useful approach, and it can obtain accurate damage detection results. However, with the development of civil engineering structures, this classical method faces two problems: one is it is only applied to simple structures rather than full-scale structures, and second is the iterative calculation efficiency is lower. Therefore, aiming at these drawbacks, the two improvement strategies have been introduced to the original method for its enhancement in the application potential and computational efficiency. The proposed method has been verified based on two examples, i.e., a numerical steel truss with 144 elements and a full-scale experimental steel truss with 160 elements. The results prove that the proposed method has better efficiency and good application potential in the practical full-scale engineering structure.

Determinants of a bank's profitability with the mediating role of interest rate spread: A case of Vietnam

Considering the fundamental function of commercial banks in the economy, which involves the facilitation of fund transfers from lenders to borrowers, it is imperative for these institutions to carry out this task in a manner that is both efficient and effective. This is crucial to fostering economic growth and enhancing social welfare. A bank's profitability has been a subject of scrutiny by researchers in many countries for decades. This study aims to analyze the impact of interest rate spread (IRS) and its mediating role in the relationship between bank-specific factors and the bank's profitability at the Commercial Bank of Vietnam. The data was collected from 2008 to 2020 for the 25 Commercial Banks using panel regression. The study found the positive effect of cost efficiency (CE), income diversity (ID), and liquidity risk (LIQ) on the IRS; however, bank size (BS), non-performing loan (NPL), provision of bad and doubtful debts (PL), asset structure (AS), non-interest expense (NIE), and economic conditions (ECD) do not impact the IRS statistically significantly. The study also confirms the IRS's mediating role. The study findings provide empirical evidence of the explaining and mediating role of the IRS on bank profitability. This study recommends that policymakers encourage Commercial Banks to diversify their income in order to avoid focusing on traditional activities, which can lead to credit overheating.

Study of Direct N7 Regioselective tert-Alkylation of 6-Substituted Purines and Their Modification at Position C6 through O, S, N, and C Substituents.

A new N7 direct regioselective method allowing the introduction of tert-alkyl groups into appropriate 6-substituted purine derivatives is developed. This method is based on a reaction of N-trimethylsilylated purines with a tert-alkyl halide using SnCl4 as a catalyst. In this work, we study the structure and optimal reaction conditions leading to the N7 isomer and in some cases also to the N9 isomer. The main goal is devoted to preparing 7-(tert-butyl)-6-chloropurine as a suitable compound for other purine transformations. The stability of the tert-butyl group at the N7 position is tested for classic model reactions, leading to the preparation of new 6,7-disubstituted purine derivatives, which is also interesting from the point of view of possible biological activity.

Modeling the morphological response of gravel–bed rivers subject to repeated sediment bypass tunnel operations

Introduction: Sediment bypass tunnels (SBTs) are operated during floods to re-establish sediment continuity past dams with the ultimate goal of decreasing accumulation in reservoirs. Depending on the location of the intake structure and operational conditions, SBTs may release either bed load-laden or bed load-free flows in the form of sudden floods (pulses). When evaluating the impacts of SBTs, the traditional approach has been to monitor channel changes in the years following project completion. However, by the time these impacts become evident, mitigation is challenging.Methods: This research adopts a forward-thinking methodology, emphasizing the prediction of potential impacts during the project’s early planning stages. We use a one-dimensional morphodynamic model to forecast the potential morphological response of a gravel-bed river with an idealized geometry to a series of SBT operations characteristic of projects in the Swiss Alps.Results: The morphological response of the downstream reach over the medium to long term is influenced by the alternating pattern of bed load-laden and bed load-free flow releases. This pattern is instrumental in forming a transition region near the SBT outlet hydrograph boundary layer (HBL).Discussion: Within the (HBL), fluctuations in bed elevation and slope are localized, while variations in grain-size distribution persist throughout the downstream region.

Pro+: Automated protrusion and critical shear stress estimates from 3D point clouds of gravel beds

AbstractThe dimensionless critical shear stress (τ*c) needed for the onset of sediment motion is important for a range of studies from river restoration projects to landscape evolution calculations. Many studies simply assume a τ*c value within the large range of scatter observed in gravel‐bedded rivers because direct field estimates are difficult to obtain. Informed choices of reach‐scale τ*c values could instead be obtained from force balance calculations that include particle‐scale bed structure and flow conditions. Particle‐scale bed structure is also difficult to measure, precluding wide adoption of such force‐balance τ*c values. Recent studies have demonstrated that bed grain size distributions (GSD) can be determined from detailed point clouds (e.g. using G3Point open‐source software). We build on these point cloud methods to introduce Pro+, software that estimates particle‐scale protrusion distributions and τ*c for each grain size and for the entire bed using a force‐balance model. We validated G3Point and Pro+ using two laboratory flume experiments with different grain size distributions and bed topographies. Commonly used definitions of protrusion may not produce representative τ*c distributions, and Pro+ includes new protrusion definitions to better include flow and bed structure influences on particle mobility. The combined G3Point/Pro+ provided accurate grain size, protrusion and τ*c distributions with simple GSD calibration. The largest source of error in protrusion and τ*c distributions were from incorrect grain boundaries and grain locations in G3Point, and calibration of grain software beyond comparing GSD is likely needed. Pro+ can be coupled with grain identifying software and relatively easily obtainable data to provide informed estimates of τ*c. These could replace arbitrary choices of τ*c and potentially improve channel stability and sediment transport estimates.

It is hot and cold here: the role of thermotolerance in the ability of spiders to colonize tree plantations in the southern Atlantic Forest.

Worldwide, with the decline of natural habitats, species with reduced niche breadth (specialists) are at greater risk of extinction as they cannot colonise or persist in disturbed habitat types. However, the role of thermal tolerance as a critical trait in understanding changes in species diversity in disturbed habitats, e.g., due to forest replacement by tree plantations, is still understudied. To examine the role of thermal tolerance on the responses of specialist and generalist species to habitat disturbances, we measured and compared local temperature throughout the year and thermotolerance traits [upper (CTmax) and lower (CTmin) thermal limits] of the most abundant species of spiders from different guilds inhabiting pine tree plantations and native Atlantic Forests in South America. Following the thermal adaptation hypothesis, we predicted that generalist species would show a wider thermal tolerance range (i.e., lower CTmin and higher CTmax) than forest specialist species. As expected, generalist species showed significantly higher CTmax and lower CTmin values than specialist species with wider thermal tolerance ranges than forest specialist species. These differences are more marked in orb weavers than in aerial hunter spiders. Our study supports the specialisation disturbance and thermal hypotheses. It highlights that habitat-specialist species are more vulnerable to environmental changes associated with vegetation structure and microclimatic conditions. Moreover, thermal tolerance is a key response trait to explain the Atlantic Forest spider's ability (or inability) to colonise and persist in human-productive land uses.

SCREENING OF THE ABILITY OF MICROORGANISMS TO BIOFILM FORMATION

Biofilms are an important element of microbial communities and perform various functions determined by their composition, structure and environmental conditions in which they are formed. Biofilms can form on various surfaces, such as soil, glass, metal, polymeric materials, and biostructures of living organisms. This process takes place with the participation of many species of microorganisms, in particular, bacteria and fungi, which, in this manner, acquire additional mechanisms for survival, in particular, in the presence of antibiotics. To test the biofilm-forming ability of bacteria (Escherichia coli, Bacillus subtilis, Lactobacillus brevis, Rhodococcus luteus, Staphylococcus albus, Azotobacterchroococcum, Pseudomonas fluorescens, Micrococcus luteus) and yeasts (Candida pseudotropicalis, C. curvata, C.kefyr, C. parapsilosis, C. tenuis, Cryptococcus lactativorus, Cryptococcus laurentii), which were affected by plant extracts, three methods were used. The ability of these microorganisms to form biofilms was not detected.

The organic carbon‐to‐clay ratio as an indicator of soil structure vulnerability, a metric focused on the condition of soil structure

AbstractThe soil organic carbon to clay ratio (SOC:clay) is a metric used in soil quality management. In Switzerland and the United Kingdom, for example, threshold values for SOC:clay ratios have been determined to indicate very good (>1:8) to degraded (<1:13) soil structures. A recent article in Soil Use and Management by Poeplau and Don, however, suggested that this metric is ‘strongly biased and misleading’, based on their observation that German sandy soils and heavy clay soils tend to show very high and very low SOC:clay ratios, respectively. An alternative metric was proposed based on the ratio of actual SOC to expected SOC level for a considered area. We offer a commentary on the proposal, arguing that because soil structure quality is overlooked by the approach, it fails to provide appropriate SOC levels for soil health and could lead to soils with highly depleted SOC being classified ‘good’. The SOC:clay ratio, on the other hand, does address soil structure condition, providing a structure vulnerability index, a key function independent of local soil management conditions. When soils are found to have high structure vulnerability, as indicated by the SOC:clay ratio, the cropping practices at the site should be investigated and ways to increase the SOC content considered. Structure condition threshold values may only need to be reassessed if it is shown that the average structure quality observed is not in conformity with the present thresholds, which would be expected for some soils, such as Andosols.