Structural Approach Research Articles

Illuminating cellular architecture and dynamics with fluorescence polarization microscopy.

Ever since Robert Hooke's 17th century discovery of the cell using a humble compound microscope, light-matter interactions have continuously redefined our understanding of cell biology. Fluorescence microscopy has been particularly transformative and remains an indispensable tool for many cell biologists. The subcellular localization of biomolecules is now routinely visualized simply by manipulating the wavelength of light. Fluorescence polarization microscopy (FPM) extends these capabilities by exploiting another optical property - polarization - allowing researchers to measure not only the location of molecules, but also their organization or alignment within larger cellular structures. With only minor modifications to an existing fluorescence microscope, FPM can reveal the nanoscale architecture, orientational dynamics, conformational changes and interactions of fluorescently labeled molecules in their native cellular environments. Importantly, FPM excels at imaging systems that are challenging to study through traditional structural approaches, such as membranes, membrane proteins, cytoskeletal networks and large macromolecular complexes. In this Review, we discuss key discoveries enabled by FPM, compare and contrast the most common optical setups for FPM, and provide a theoretical and practical framework for researchers to apply this technique to their own research questions.

Aggregation/agglomeration dependent percolation threshold of spherical nanoparticles in electrically conductive polymer nanocomposites

AbstractThis study evaluated the percolation threshold in polymer nanocomposites and its dependence on the aggregation/agglomeration phenomenon. The main objective of the investigation was to propose a particular method that besides revealing the impact of different involved parameters on the percolation threshold could also provide useful information regarding the system characteristics. In line with that, a specific geometrical structure was employed to represent the clusters and assess the variation of the percolation threshold and characteristics of the polymer/particle interphase region. The findings were applied in an improved form of the percolation theory to perform validation against the related experimental data. Improvement was conducted by involving the impact of the newly estimated percolation threshold, aggregations/agglomerations, interphase region, and so forth. Also, specific theories were employed to define the electrical conductivity of the nanoparticle clusters and interphase region. The results showed that the percolation threshold is directly affected by the content of the nanoparticles and the characteristics of the aggregates/agglomerates. Besides, it was revealed that parameters, such as the size of nanoparticles, physical characteristics of the polymer matrix and interphase region, dispersion quality, etc. may substantially affect the percolation threshold and subsequently other physical properties of the system, such as electrical conductivity.Highlights A structural approach toward understanding the percolation phenomenon. Defining the particular dependence of percolation threshold on dispersion quality. Estimating the content of aggregates/agglomerates using percolation theory. Improving the percolation theory to predict the electrical conductivity. Applying the scaling theory to define the electrical conductivity of the interphase.

Links between disasters of natural origin, economic development and gender inequality: evidence for latin America and the Caribbean

AbstractThis paper explores the relationship between gender and disasters of natural origin (ND) by considering how the level of economic growth influences the losses caused by these events and how disasters also contribute to gender inequality. To this end, the effects of ND occurring during the 2000–2021 period in 20 countries in Latin America and the Caribbean are analysed using a structural equation approach with fixed effects panel data (SEM-FE) as an analytical tool. The results obtained are in line with previous literature that identifies population growth and economic growth as variables that drive the increase in loss of human life from NDs. The results show evidence of the mitigating effects of gender equality on the impact of NDs measured in terms of human life and of the negative effects of the impact of NDs on gender equality. The findings reinforce gender equality as a key element in preventing disasters and rebuilding a sustainable environment in their aftermath.

Structural dynamics of the intrinsically disordered linker region of cardiac troponin T.

Troponin plays a central role in regulating heart contraction, and mutations in troponin can cause human cardiomyopathies. There are several functionally-significant regions of troponin that have not been structurally resolved, including the troponin T linker region that contains multiple cardiomyopathy mutations. In these unresolved regions, it is not possible to understand how changes in sequence affect function. We used computational and experimental techniques to demonstrate that this linker is dynamic and intrinsically disordered both in isolation and in the fully regulated thin filament. Moreover, we show how a cardiomyopathy mutation in this region affects function via allosteric disruption of intermolecular interactions. Our results highlight the need to consider how key mutations affect troponin disorder rather than the structure-function relationship.

Analytical calculation approach for rocket nose cone structure with orthotropic material

The Authors of this research developed an analytical calculation method to estimate the strength of nose cone structures made of orthotropic materials, which were crucial components in aircraft and spacecraft. Strength analysis of nose cones had been comprehensively addressed for isotropic materials; however, the lack of efficient approaches for orthotropic materials presented a challenge. In this research, a new analytical method was proposed, combining membrane stress theory for isotropic materials with classical laminate theory for orthotropic materials. This approach enabled the determination of stresses on the nose cone shell structure in both meridional and circumferential directions in an efficient and straightforward manner. The analysis results indicated that the developed analytical method exhibited stress distribution trends similar to those obtained using the Finite Element Method. Stresses in the +45° and –45° direction, as well as in-plane shear stress and Tsai-Wu failure indices, showed trend similarity between the two methods. Despite specific numerical differences in the calculation results, these consistent trends suggested that the analytical method could serve as a tool for the preliminary design of a nose cone structure with a similar configuration analyzed in this study.

Physics-informed neural networks for V-notch stress intensity factor calculation

This paper proposes a physics-informed neural networks (PINNs) based approach for elastic structures with a V-notch, by which the displacement field, stress field as well as the V-notch stress intensity factor (NSIF) can be obtained through artificial neural networks. A PINN model is established for V-notch structures, integrating physical information into a deep neural network to ensure adherence to physical laws while fitting observational data. Subsequently, an adaptive local sampling strategy for V-notch structures is adopted, generating locally dense Gaussian points sampling around regions of stress concentration. Based on this, a sequential PINNs approach for V-notch structures is then established to calculate the NSIF for V-notch structures with arbitrary notch angles. Finally, the effectiveness of the proposed method is validated through three numerical examples. The results demonstrate the method can accurately predict the NSIFs for V-notch structures across a spectrum of opening angles. Compared to the traditional data-driven method, the proposed method is able to more effectively compute the NSIF of V-notch structures due to the integration of physical information and observational data.

Consumer skepticism towards organic beauty products Cross-country research

Based on the attitude–behaviour–context (ABC) theory, the present study addressed consumer skepticism as one of the inhibitors of organic purchasing behaviour. More specifically, it investigated the role of environmental concern and environmental knowledge as a mediator, in the organic cosmetics background. Data gathered from consumers in Tunisia (N = 736), Italy (N = 720) and France (N = 715) and analysed using a structural equation modelling approach. The findings revealed that green skepticism is a strong inhibitor towards adoption of organic cosmetic products among consumers in the three countries. On the other hand, findings revealed that environmental knowledge and environmental concern fully mediate the relationship between green skepticism and organic purchasing behaviour. The ultimate goal is to provide valuable insights for business leaders, policymakers and marketers fully understand consumers’ resistance to organic cosmetic products. Further, it offers a comprehensive framework to support strategies to reduce consumers’ skepticism towards organic products, in different market segments.

Decentring the West? Civilizational solidarity and (de)colonization in theories of the Russia-Ukraine War

ABSTRACT Since Russia’s invasion of Ukraine in 2022, a growing literature promoting the Ukrainian national cause, framed in decolonial terms, has influenced public discourse about the Russia-Ukraine War in the West. Filtered through the activist interpretation of cultural epistemologies, with their emphasis on the centring and decentring of knowledges, the war has been imagined primarily as a colonial emanation of a Russian narrative. We argue that the heavily moralized notion of epistemological and mental decolonization has impeded critical investigation into the degree of responsibility for, and the NATO powers’ involvement in, the Russia-Ukraine War. In order to attain a rigorous analysis of all actors’ motives and rationalities, we argue for the need to understand the conflict's structural and historical dimensions, and thus to draw from the classical, structural approaches to analysing imperial power that predate the cultural turn.

Advanced Laser Techniques for the Development of Nature-Inspired Biomimetic Surfaces Applied in the Medical Field

This review focuses on the innovative use of laser techniques in developing and functionalizing biomimetic surfaces, emphasizing their potential applications in the medical and biological fields. Drawing inspiration from the remarkable properties of various natural systems, such as the water-repellent lotus leaf, the adhesive gecko foot, the strong yet lightweight spider silk, and the unique optical structures of insect wings, we explore the potential for replicating these features through advanced laser surface modifications. Depending on the nature and architecture of the surface, particular techniques have been designed and developed. We present an in-depth analysis of various methodologies, including laser ablation/evaporation techniques, such as Pulsed Laser Deposition and Matrix-Assisted Pulsed Laser Evaporation, and approaches for laser surface structuring, including two-photon lithography, direct laser interference patterning, laser-induced periodic surface structures, direct laser writing, laser-induced forward transfer, and femtosecond laser ablation of metals in organic solvents. Additionally, specific applications are highlighted with the aim of synthesizing this knowledge and outlining future directions for research that further explore the intersection of laser techniques and biomimetic surfaces, paving the way for advancements in biomedical applications.

Acoustic radiation characteristics of shark skin inspired surface modified plates

This paper aims to evaluate the acoustic radiation characteristics of thin plates featuring a layer of small-scale biomimetic shark skin type additive surface treatment. The shark skin dermal denticles are modelled as point masses arranged in a bi-directional pattern on both the upper and lower surfaces of the plate. The governing equations are obtained through a variational approach, incorporating the Dirac Delta function in the derivation of the proposed semi-analytical model for the shark skin layer. A semi-analytical method based on the Rayleigh–Ritz formulation is utilized to analyze the vibrations of these plates with surface modification. The sound radiation characteristics are then derived from the solution of the Rayleigh integral. A comprehensive investigation is performed on the influence of surface modification on different vibro-acoustic characteristics, using a continuous structural mode and power transfer matrix-based approach. Notable observations include a reduction in peak vibro-acoustic responses with dense denticle arrangements, especially at resonance, demonstrating a direct relationship with mass ratios, i.e., the ratio of denticle mass to plate mass. The study further reveals a shift of vibro-acoustic responses towards low frequencies with an increase in mass ratios. A thorough comparative study indicates that while additive surface modifications inspired by shark skin may weaken sound radiation characteristics at resonance frequencies, a reverse effect can be observed at intermittent operational frequencies.

Determinants of consuming functional fermented foods: An integrated structural model approach

Functional fermented foods are increasingly recognized for their positive impact on human health, and this study aims to identify the factors that influence these products’ consumption in Iran. The study uses structural equation modeling (SEM) to test the conceptual model incorporating the theory of planned behavior (TPB), protection motivation theory (PMT), and flow theory (FT). Data from 319 individuals having prior experience with such foods were analyzed to test the hypothesized relationships. Based on the results, the integrated model components demonstrated a strong predictive power, explaining 70.6% of the variance in functional fermented food consumption. The study found that perceived vulnerability, perceived severity, and response cost from the PMT were the main drivers of functional fermented food consumption among Iranians. The study also offers practical insights, including highlighting health benefits, promoting pleasurable aspects, and mitigating accessibility challenges to these foods for Iranian consumers.

Modelling the effects of perceived system quality and personal innovativeness on the intention to use metaverse: a structural equation modelling approach

The metaverse, an interactive and immersive 3D virtual environment, has recently become popular and is widely used in several fields, including education. However, the successful use of metaverse relies on the extent to which users intend to adopt and use it. Close examination of this critical issue reveals a lack of research that examines the effects of certain factors on users’ intentions toward using metaverses. Thus, this study extends the technology acceptance model by integrating two constructs—perceived system quality and students’ personal innovativeness. Using a survey to collect data, 164 responses were received from students at the University of Ha’il in Saudi Arabia. Two steps in structural equation modelling (SEM) using the AMOS software were applied to analyse the data and test the research hypotheses. The results revealed that perceived system quality had a significant effect on students’ intentions to use metaverses through perceived ease of use. Furthermore, personal innovativeness had a significant effect on students’ intentions through the perceived usefulness of the metaverse. In addition, perceived usefulness affected students’ intentions to use a metaverse. Surprisingly, perceived ease of use had an insignificant effect on students’ intentions to use the metaverse. Although the proposed model and its findings contribute to the technology acceptance model (TAM) literature, the study’s practical value is significant because it can help educational policymakers and authorities to understand the effect of each factor and plan future strategies. Additionally, the findings of this study can assist practitioners, designers, and developers in designing and promoting the utilisation of metaverses.

Molecular Basis of the Recognition of the Active Rab8a by Optineurin

Optineurin (OPTN), a multifunctional adaptor protein in mammals, plays critical roles in many cellular processes, such as vesicular trafficking and autophagy. Notably, mutations in optineurin are directly associated with many human diseases, such as amyotrophic lateral sclerosis (ALS). OPTN can specifically recognize Rab8a and the GTPase-activating protein TBC1D17, and facilitate the inactivation of Rab8a mediated by TBC1D17, but with poorly understood mechanism. Here, using biochemical and structural approaches, we systematically characterize the interaction between OPTN and Rab8a, revealing that OPTN selectively recognizes the GTP-bound active Rab8a through its leucine-zipper domain (LZD). The determined crystal structure of OPTN LZD in complex with the active Rab8a not only elucidates the detailed binding mechanism of OPTN with Rab8a but also uncovers a unique binding mode of Rab8a with its effectors. Furthermore, we demonstrate that the central coiled-coil domain of OPTN and the active Rab8a can simultaneously interact with the TBC domain of TBC1D17 to form a ternary complex. Finally, based on the OPTN LZD/Rab8a complex structure and relevant biochemical analyses, we also evaluate several known ALS-associated mutations found in the LZD of OPTN. Collectively, our findings provide mechanistic insights into the interaction of OPTN with Rab8a, expanding our understanding of the binding modes of Rab8a with its effectors and the potential etiology of diseases caused by OPTN mutations.

Assessing the multi-dimensional effects of air pollution on maternal complications and birth outcomes: A structural equation modeling approach

ObjectiveThis cross-sectional study aims to investigate the direct and indirect relationships between exposure to a metal mixture in air and adverse pregnancy outcomes across gestational stages. MethodsWith 46,829 births in 2021 in two Florida counties and Air Quality System data, structural equation modeling was used to construct latent metal mixtures in PM2.5 and unravel their effects on pregnancy complications (preeclampsia and gestational diabetes) and birth outcomes (low birth weight and preterm birth risks). ResultsA latent variable featuring seven metals (Aluminum, Calcium, Iron, Magnesium, Manganese, Silicon, Vanadium) was identified through the measurement model. The latent metal mixture exposure had direct effects on gestational diabetes and preterm birth (1st trimester, 2nd trimester), low birth weight (1st trimester), and preeclampsia (2nd trimester). When considering total effects, the effects on low birth weight in the 1st trimester and on preeclampsia in 2nd trimester were masked, and the latent metal mixture increased the low-birth-weight risk in 2nd trimester by 2 % (OR = 1.02, 95 % CI = [1.00, 1.03]). ConclusionThis study reveals time-dependent associations between a metal mixture in PM2.5 exposure and adverse pregnancy outcomes, highlights the need to address dust in PM2.5, and provides additional evidence for understanding the pathway of the pollution effects on fetal health.

Chinese investments in Argentina's lithium sector: Economic development implications amid global competition

Latin American countries, rich in key transition materials, have emerged as significant suppliers for China and key destinations for Chinese investment. These engagements have coincided with rising global competition among Chinese, and other leading companies to access these materials. Argentina serves as a notable example of these trends.This paper analyzes Chinese investments in Argentina's lithium sector, focusing on the implications for the country's economic development and international insertion. Drawing on the contributions of Latin American structuralism and other approaches that emphasize the centrality of the State in promoting innovation and complexity in the production system, the paper explores the challenges faced by peripheral countries like Argentina in advancing development within the global center-periphery relations.Our study employs an exploratory approach based on qualitative analysis of various sources. We first identify the distinctive characteristics of Chinese firms’ overseas strategies and interests in Argentina. Next, we examine the domestic and global factors constraining Argentina's ability to add value locally. In the conclusions, we summarize the challenges Argentina faces regarding the industrialization of lithium and highlight the critical role of the State in fostering the development of these capacities.

Adaptive Leadership, Employee Recognition and Employee Engagement as Mediator to Employee’s Agility: The Point of View from Supervisors Level Up to Manager

There are three aims of this research: to determine the role of employee recognition on employee agility, the role of adaptive leadership on employee agility, and the role of employee engagement as a mediator between adaptive leadership and employee recognition on employee agility from supervisor’s level up to manager in a manufacturing company focuses in automotive in Jakarta. This research is based on a comprehensive review of existing literature on adaptive leadership, employee recognition, engagement, and agility. The research approach applied in this study is quantitative, using a Partial Least Square Structural Equation Modelling analysis approach. The data for this research was collected through purposive sampling, with the object of this research being one of the subsidiary companies that has implemented the employee agility approach. The findings of this research indicate that adaptive leadership does not have a significant positive influence on employee agility, nor does employee recognition. Additionally, employee engagement was found not to mediate the influence of employee recognition on employee agility.

Modelling of passengers behaviour under the influence of noise in public transport buses: a structural equation approach

This study aims to investigate the impact of noise pollution levels on passengers during travel. Specifically, the aim was to explore the interconnections between noise-induced annoyance, sensitivity to noise, sleep disturbances, and physical health problems using a structural equation modelling (SEM) approach. 14 routes were selected for detailed analysis across different time periods. The noise levels were observed, and the impact of these levels on passengers was assessed through a questionnaire survey to know their perception towards noise and its impacts. A total of 252 responses from passengers were collected through the personal interview. Findings reveal that noise pollution levels exceeded 70 dBA on most of the routes. A significance test (t-test) conducted on 15-minute frequency intervals showed no significant difference in noise pollution levels during morning, evening, and afternoon periods. Subjective analysis indicates 31% of passenger were found to be highly annoyed due to noise within public buses. Additionally, 32% and 9% of passengers reported moderate and minimal annoyance, respectively, attributed to traffic and engine noise inside buses. Structural equation approach showed that sensitivity to noise affects the annoyance level most with coefficient 0.76, followed by physical health factors and sleep disturbance with coefficient 0.48 and 0.44 respectively.

Lost in the maze? Public sector accounting and reporting—A structured literature review

IMPACT Motivated by the complexity and challenges of public sector accounting, this structured literature review (SLR) takes a broad approach combined with structured analysis to unravel the development, cross-temporal challenges and remaining gaps in public sector accounting and reporting research. By highlighting these gaps, the authors outline future research paths within the current literature and compare them with previous literature reviews to provide researchers with a roadmap for future research. Although this SLR does not provide direct assistance with day-to-day problems, through its comparative, quantitative and structured approach, it provides practitioners with an interdisciplinary overview of public sector accounting research in one article—helping them to navigate the complex field of public sector accounting without having to read multiple literature reviews.

Creative use of soundscape/smellscape protocols for integrated spatial understandings

This paper reviews an experimental workshop exploring creative ways to use soundscape and smellscape protocols for better spatial understandings. It aims to find out how visual methods such as drawing and making could contribute to the recall process. The reflections of the experimental work address the challenge of gaining integrated spatial information of the sonic and olfactory environments through the current approach based on protocols (e.g. psychoacoustic parameters such as eventful-monotonous, vibrant-chaotic, etc.) and interviews. The protocol is found useful to get an abstract impression of the overall soundscape and smellscape with sound and smell marks. Sound memories are found less object-related whilst smell memories are expressed less in sketches. The discussion suggests a more structured narrative approach will be useful when integrating such artistic methods for spatial details. The sketching and objects making task stimulates crossmodal recall of auditory and olfactory memories.

Occupational exposure to organic solvents during pregnancy and child behavior from early childhood to adolescence

BackgroundOrganic solvents are used in formulating an extensive range of products for professional use. Animal and human studies suggest that in utero solvent exposure may affect neurodevelopment. Our objective was to assess the association between occupational exposure to solvents during pregnancy and child behavior aged 2–12 years.MethodsThe French mother-child cohort PELAGIE (2002–2006) included 3,421 women recruited in early pregnancy. Occupational exposure to solvents was self-reported. For 459 children, parents used a questionnaire derived from the Child Behavior Checklist and the Preschool Social Behavior Questionnaire to assess their child’s behavior, at age 2, and the Strengths and Difficulties Questionnaire at ages 6 and 12. A cross-lagged structural equation modeling approach was used to assess direct and indirect associations between exposure and child behavior.ResultsAt age 2, an increased externalizing behavior score was suggested with prenatal exposure to solvents (mean change in standardized score (95%CI): 0.28 (-0.01, 0.57) for occasional exposure and 0.23 (-0.05, 0.51) for regular exposure). At ages 6 and 12, distinct sex-specific patterns were observed: among boys, no association with externalizing behavior was observed, while among girls, an association was seen for both occasional and regular exposure (total effect at age 12: 0.45 (0.06,0.83) and 0.40 (0.03, 0.76), respectively). For both sexes, occasional exposure may be associated with internalizing behavior at ages 6 and 12 (total effect at age 6: 0.37 (0.06, 0.68) and at age 12: 0.27 (-0.08, 0.62)).ConclusionsOccupational exposure to solvents during pregnancy may impact child behavior through either direct or cumulative effects during childhood; these associations may persist until early adolescence, especially among girls.