Complex Arrangement Research Articles

Modulation of the Enzymatic Activity of the Flagellar Lytic Transglycosylase SltF by Rod Components and the Scaffolding Protein FlgJ in Rhodobacter sphaeroides.

Macromolecular cell-envelope-spanning structures such as the bacterial flagellum must traverse the cell wall. Lytic transglycosylase enzymes are capable of enlarging gaps in the peptidoglycan meshwork to allow the efficient assembly of supramolecular complexes. In the periplasmic space, the assembly of the flagellar rod requires the scaffold protein FlgJ, which includes a muramidase domain in the canonical models Salmonella enterica and Escherichia coli. In contrast, in Rhodobacter sphaeroides, FlgJ and the dedicated flagellar lytic transglycosylase SltF are separate entities that interact in the periplasm. In this study, we show that sltF is expressed, along with the genes encoding the early components of the flagellar hierarchy that include the hook-basal body proteins, making SltF available during the rod assembly. Protein-protein interaction experiments demonstrated that SltF interacts with the rod proteins FliE, FlgB, FlgC, FlgF, and FlgG through its C-terminal region. A deletion analysis that divides the C terminus in two halves revealed that the interacting regions for most of the rod proteins are not redundant. Our results also show that the presence of the rod proteins FliE, FlgB, FlgC, and FlgF displace the previously reported SltF-FlgJ interaction. In addition, we observed modulation of the transglycosylase activity of SltF mediated by FlgB and FlgJ that could be relevant to coordinate rod assembly with cell wall remodeling. In summary, different mechanisms regulate the flagellar lytic transglycosylase, SltF, ensuring a timely transcription, a proper localization and a controlled enzymatic activity. IMPORTANCE Several mechanisms participate in the assembly of cell-envelope-spanning macromolecular structures. The sequential expression of substrates to be exported, selective export, and a specific order of incorporation are some of the mechanisms that stand out to drive an efficient assembly process. Here, we analyze how the structural rod proteins, the scaffold protein FlgJ and the flagellar lytic enzyme SltF, interact in an orderly fashion to assemble the flagellar rod into the periplasmic space. A complex arrangement of transient interactions directs a dedicated flagellar muramidase toward the flagellar rod. All of these interactions bring this protein to the proximity of the peptidoglycan wall while also modulating its enzymatic activity. This study suggests how a dynamic network of interactions participates in controlling SltF, a prominent component for flagellar formation.

Ethnography in Health Services Research: Oscillation Between Theory and Practice.

The well-known divergence between what policy and protocol look like on paper, and what happens in the actual practice of daily life remains a central challenge in health services provision and research. This disparity is usually referred to as the theory–practice gap and contributes to concerns that scientific evidence fails to make substantial impacts on the processes of service delivery. In this article, we present an argument for the inclusion of ethnographic methods in health services research and show that this approach enables researchers to address this divergence by working within it. We trace how ethnography, through generative processes of oscillation, can take us beyond lamenting the gap and capture the relational dynamics of people working together in complex systemic arrangements. By moving from example to methodological reflection, to principle of research, we demonstrate how the oscillation of ethnographic research between theory and practice can productively contribute to the field of health service research.

Spatial Patterns of Light-Harvesting Antenna Complex Arrangements Tune the Transfer-to-Trap Efficiency of Excitons in Purple Bacteria.

In photosynthesis, the efficiency with which a photogenerated exciton reaches the reaction center is dictated by chromophore energies and the arrangement of chromophores in the supercomplex. Here, we explore the interplay between the arrangement of light-harvesting antennae and the efficiency of exciton transport in purple bacterial photosynthesis. Using a Miller-Abrahams-based exciton hopping model, we compare different arrangements of light-harvesting proteins on the intracytoplasmic membrane. We find that arrangements with aggregated LH1s have a higher efficiency than arrangements with randomly distributed LH1s in a wide range of physiological light fluences. This effect is robust to the introduction of defects on the intracytoplasmic membrane. Our result explains the absence of species with aggregated LH1 arrangements in low-light niches and the large increase seen in the expression of LH1 dimer complexes in high fluences. We suggest that the effect seen in our study is an adaptive strategy toward solar light fluence across different purple bacterial species.

Between the Nile and the Red Sea

Abstract The Medjay were a group of desert nomads inhabiting the region between the Nile and the Red Sea contemporaneous to the Bronze Age of Ancient Egypt (c. 3100-1050 bce). Well-known from textual sources from Pharaonic Egypt and Kushite Nubia, it has proven difficult to produce basic societal descriptions of the Medjay and their political status, especially in their desert heartland. Most studies dedicated to the Medjay evaluate their presence as a nomadic diaspora and emigres on the Nile or focus on their interaction with the Ancient Egyptian state. These approaches place little emphasis on their indigenous geography and nomadic heritage in the Red Sea Hills. This study takes a very different tact and attempts to reconstruct some basic information on their political geography in their indigenous homeland. Although the sources, both textual and archaeological, are currently scarce regarding a Second Millennium bce desert occupation, they do demonstrate complex arrangements between Medjay political actors and nearby states. Particularly notable was the ability of individual tribes to enact varying policies of entente, détente, and aggression towards their Nile neighbours as well as exercise de facto sovereignty over a wealthy desert consistently threatened by Egyptian and Kushite imperialism.

RoboCOP: jointly computing chromatin occupancy profiles for numerous factors from chromatin accessibility data.

Chromatin is a tightly packaged structure of DNA and protein within the nucleus of a cell. The arrangement of different protein complexes along the DNA modulates and is modulated by gene expression. Measuring the binding locations and occupancy levels of different transcription factors (TFs) and nucleosomes is therefore crucial to understanding gene regulation. Antibody-based methods for assaying chromatin occupancy are capable of identifying the binding sites of specific DNA binding factors, but only one factor at a time. In contrast, epigenomic accessibility data like MNase-seq, DNase-seq, and ATAC-seq provide insight into the chromatin landscape of all factors bound along the genome, but with little insight into the identities of those factors. Here, we present RoboCOP, a multivariate state space model that integrates chromatin accessibility data with nucleotide sequence to jointly compute genome-wide probabilistic scores of nucleosome and TF occupancy, for hundreds of different factors. We apply RoboCOP to MNase-seq and ATAC-seq data to elucidate the protein-binding landscape of nucleosomes and 150 TFs across the yeast genome, and show that our model makes better predictions than existing methods. We also compute a chromatin occupancy profile of the yeast genome under cadmium stress, revealing chromatin dynamics associated with transcriptional regulation.

Dynamic load distribution of planetary gear sets subject to both internal and external excitations

Planetary gearsets are widely used in several mechanical systems and have numerous advantages over counter-shaft gears. Despite this, the complex arrangement of components in a planetary gear system makes them susceptible to noise and vibration issues. An exhaustive and rich literature is available on the topic of planetary gear dynamics, but most of these studies consider only the parametric excitation of gear mesh contacts while assuming an ideal power source. But contrary to this popular assumption, realistic power sources (IC Engine, electric motor, wind turbine, etc.) could be subjected to torque fluctuations based on the operating conditions. The current study presents a theoretical investigation on the load distribution and dynamic behavior of planetary gear sets subjected to both internal and external excitations. A three-dimensional dynamic planetary load distribution model that inherently captures the internal excitation due to the elastic gear mesh contacts is employed in this study. The influence of operating conditions on both system-level response and local gear mesh contact stress distribution are explored. Discussed results not only illustrate the potential of the dynamic model but also reinforce the need for such computationally efficient models for design and analysis purposes.

Super-resolution microscopy reveals the arrangement of inner membrane protein complexes in mammalian mitochondria.

The mitochondrial inner membrane is a protein-rich environment containing large multimeric complexes, including complexes of the mitochondrial electron transport chain, mitochondrial translocases and quality control machineries. Although the inner membrane is highly proteinaceous, with 40-60% of all mitochondrial proteins localised to this compartment, little is known about the spatial distribution and organisation of complexes in this environment. We set out to survey the arrangement of inner membrane complexes using stochastic optical reconstruction microscopy (STORM). We reveal that subunits of the TIM23 complex, TIM23 and TIM44 (also known as TIMM23 and TIMM44, respectively), and the complex IV subunit COXIV, form organised clusters and show properties distinct from the outer membrane protein TOM20 (also known as TOMM20). Density based cluster analysis indicated a bimodal distribution of TIM44 that is distinct from TIM23, suggesting distinct TIM23 subcomplexes. COXIV is arranged in larger clusters that are disrupted upon disruption of complex IV assembly. Thus, STORM super-resolution microscopy is a powerful tool for examining the nanoscale distribution of mitochondrial inner membrane complexes, providing a 'visual' approach for obtaining pivotal information on how mitochondrial complexes exist in a cellular context.

Vocal Folds Analysis for Detection and Classification of Voice Disorder

The detection and description of pathological voice are the most important applications of voice profiling. Currently, techniques like laryngostroboscopy or surgical microlarynoscopy are popularly used for the diagnosis of voice pathologies but are invasive in nature. Disorders of vocal folds impact the quality of voice, and therefore, the accuracy of voice profiling is reduced. This paper presents a better solution to differentiate normal and pathological voices based on the glottal, physical, and acoustic and equivalent electrical parameters. These parameters have been correlated using mathematical equations and models. Results reveal that the glottal flow is strongly influenced by physical parameters like stiffness and viscosity of vocal folds in case of pathological voice. However, their direct measurement requires complex invasive medical procedures or costly and complex electronic hardware arrangements in case of non-invasive methods. Glottal parameters, on the other hand, facilitate much simpler estimation of vocal folds disorders. In this work, the authors have presented two non-invasive approaches for better accuracy and least complexity for differentiating normal and pathological voices: 1) by using correlation of glottal and physical parameters, 2)by using acoustic and equivalent electrical parameters.

Effect of Lateral Spacing of Structures on Tsunami-Induced Scour

April Le Quéré, P.; Nistor, I., and Mohammadian, M., 2021. Effect of lateral spacing of structures on tsunami-induced scour. Journal of Coastal Research, 37(4), 813–826. Coconut Creek (Florida), ISSN 0749-0208.Tsunamis are a devastating force, as seen by the extreme tsunamis that struck the Indian and Pacific Oceans over the past two decades: the 2004 Indian Ocean Tsunami, the 2010 Chile Tsunami, and the 2011 Tohoku Japan Tsunami. In those events, flood-induced scouring was found to be an important phenomenon that often led to infrastructure damage. Past research has focused on scouring around single columns and other isolated horizontal structures to attempt to understand the complex processes characterizing this phenomenon. However, given that coastal cities often comprise complex arrangements of multiple structures, often crammed, tsunami inundation flow often finds concentrated paths in between such structures; these flow concentrations increase the resulting scouring. This research is an attempt to inform the scientific community on the potential of augmented scour attributable to flow concentration that is due to the lateral spacing of structures and to compare it with nonconcentrated flow-induced scour. The authors employed the FLOW-3D numerical model for this study. This model was first calibrated using a physical model experiment performed in the dam break flume of the University of Ottawa, Canada. Results from this study demonstrate that flow concentration due to the lateral spacing of structures leads to greater scouring than for the case of an isolated structure and that the magnitude of the scour, for most cases studied, was larger than what is prescribed by the latest building codes.

사전에서의 의미 구분 및 배열 방법론 연구 - 국어사전 및 프랑스어 사전을 중심으로 -

The standard of semantic arrangement among the microstructures of dictionaries is not fully elucidated neither at the level of dictionary compilation nor at the level of lexicographic research. The principle of arrangement of meanings in each dictionary is closely related to the compilation philosophy and the intended forms of dictionaries. In this paper, through the examples of Korean and French dictionaries, under the hypothesis that the arrangement strategy of multiple acceptions, that is, of the polysemy, selected order determines the form and identity of the dictionary, it is intended to show that it is a structure of order and hierarchy based on analogy and cognitive logic, rather than the enumeration and parallelism of semantic acceptions. For example, <Littré Dictionary> has a historical point of view, <PL> adopts a thoroughly synchronic attitude, and <PR> hass a unique hierarchical structure that synthesizes diachronic and synchronic point of views. In particular, <PR> explores the problem of how to establish a semantic continuum as well as the direction of subdividing meanings for a complex semantic arrangement structure. More specifically, we have analyzed different types of numbering of meanings, highlighting above all cases where specialized meanings are described under the same number, with other terminological meanings or other general meanings. Sens splitting or degrouping as well as sens lumping or regrouping methodologies are relevant to make understandable sinuous polysemes, ramified in all directions.

Bound States in the Continuum Underpin Near‐Lossless Maximum Chirality in Dielectric Metasurfaces

AbstractMetasurfaces without a mirror symmetry may exhibit chiral electromagnetic response that differs substantially from any type of polarization transformation. A typical design of chiral metasurfaces is based on a complex arrangement of meta‐atoms with chiral shapes assembled into rotationally symmetric arrays. Here it is demonstrated that, in a sharp contrast to our intuition, metasurfaces that break all point symmetries can outperform their rotationally symmetric counterparts and exhibit near‐lossless maximum chirality. The authors employ the special type of high‐quality‐factor resonances—bound states in the continuum (BICs)—that are manifested in physical systems as quasi‐BICs, and allow engineering the coupling of light with resonant metasurfaces to achieve maximum chirality. A dielectric metasurface composed of pairs of rectangular bars is designed that fully transmits one circular polarization of light and resonantly reflects the other circular polarization without any polarization conversion. Proof‐of‐concept experimental results that confirm directly the prediction of maximum chiral response of the BIC‐empowered asymmetric resonant dielectric metasurfaces are presented.

Double-helical assembly of heterodimeric nanoclusters into supercrystals.

DNA has long been used as a template for the construction of helical assemblies of inorganic nanoparticles1-5. For example, gold nanoparticles decorated with DNA (or with peptides) can create helical assemblies6-9. But without such biological ligands, helices are difficult to achieve and their mechanism of formation is challenging to understand10,11. Atomically precise nanoclusters that are protected by ligands such as thiolate12,13 have demonstrated hierarchical structural complexity in their assembly at the interparticle and intraparticle levels, similar to biomolecules and their assemblies14. Furthermore, carrier dynamics can be controlled by engineering the structure of the nanoclusters15. But these nanoclusters usually have isotropic structures16,17 and often assemble into commonly found supercrystals18. Here we report the synthesis of homodimeric and heterodimeric gold nanoclusters and their self-assembly into superstructures. While thehomodimeric nanoclusters form layer-by-layer superstructures, the heterodimeric nanoclusters self-assemble into double- and quadruple-helical superstructures. These complex arrangements are the result of two different motif pairs, one pair per monomer, where each motif bonds with its paired motif on a neighbouring heterodimer. This motif pairing is reminiscent of the paired interactions of nucleobases in DNA helices. Meanwhile, the surrounding ligands on the clusters show doubly or triply paired steric interactions. The helical assembly is driven by van der Waals interactions through particle rotation and conformational matching. Furthermore, the heterodimeric clusters have a carrier lifetime that is roughly 65 times longer than that of the homodimeric clusters. Our findings suggest new approaches for increasing complexity in the structural design and engineering of precision in supercrystals.

Cis-Bis(L-DOPA-κ2N,O)copper(II) monohydrate: synthesis, crystal structure, and approaches to the analysis of pseudosymmetry.

The crystal structure of the cis isomer of cis-bis(L-DOPA-κ2N,O)copper(II) monohydrate (L-DOPA is 3,4-dihydroxy-L-phenylalanine) (CuLD), [Cu(C9H10NO4)2]·H2O, is a singular example of a structurally characterized, homoleptic, crystalline metal L-DOPA complex. CuLD crystallizes in the space group P21, with Z' = 2. The two independent molecules are square planar, and are interconnected by a linear hydrogen-bonded chain containing 12 independent hydrogen bonds. The copper ions in both molecules have weak apical intermolecular Cu...O interactions [2.739 (2) and 2.973 (2) Å] with catechol -OH groups. A survey of the Cambridge Structural Database suggested that cis and trans isomers of Cu(NH2-C-CO2)2 amino acid complexes are equally likely to occur. 12 strong O-H...O and N-H...O hydrogen bonds stabilize an unusual linear arrangement of the Cu complexes. The Cu...Cu' distances along the chain are nearly equal [5.0739 (3) and 5.1107 (3) Å] and the Cu...Cu'...Cu angles are nearly linear [176.75 (1)°]. The MATCH procedure available in the Oxford University Crystals for Windows package was used to carry out a detailed analysis of the relationship between the two independent molecules. MATCH has some particular advantages in studying the details of pseudosymmetry, which include: (i) no atomic-order requirements; (ii) the pseudosymmetry matrix is readily available, which allows quick insight into the symmetry elements involved and their location; and (iii) the differences between molecular centroids, as well as between all atomic positions and torsion angles, are listed. A tutorial presentation is designed to attract new users to the technique. In the present case, a search for a pseudosymmetric relationship between the two independent molecules showed that they are related by a pseudo-42 axis along the crystallographic c direction. A detailed analysis shows that the pseudo-42 symmetry is disrupted by torsions about the CH2-C(ipso) bonds, and that there is no supergroup that can be used to describe the crystal structure.

Influence Assessment of the Information Concerning the Bearing Type of Axle Box of Cars on the Automatic Classification Accuracy of Heated Boxes

Purpose. The main purpose of the work is to determine and classify the heated cars’ boxes based on the probability of appearance of roller and cassette type boxes in the classes of heated and overheated boxes, as well as the laws of probability density distribution of the recognition signs of normally heated and overheated roller and cassette type boxes. Methodology. The operation features of freight cars with cassette type axle boxes with increased operating heating have been investigated. The methodology of assessing the probability of recognition errors was proposed, which takes into account the fact that sets of normally heated and overheated boxes consist of subsets of boxes with different types of bearings. A system of equations is obtained, the roots of which represent еру values that minimize the recognition probability of the errors of the heated boxes. Findings. It was found out that with some methods of determining the bearing type, for example, by the average value of the ranges of thermal image for each car, the probability of erroneous selection may depend on the probability density distribution of the sign for bearings of different types and the threshold value of this sign. The optimal thresholds for detecting the overheated roller boxes in comparison with the optimal thresholds for detecting overheated cassette boxes were determined. It has been established that the pass of an overheated cassette bearing, provided that the type of bearing is determined correctly, is less likely to lead to an accident than if the cassette box is classified as a roller box. The rejection criteria of axle boxes according to their heating temperature difference on one of the wheel set axis for three variants of settings of the alarm system according to an arrangement of multipurpose complexes of technical means (CTM) were formulated. The practical implementation of this method of adjusting the CTM settings for the Minsk branch of the Belarusian Railways was demonstrated. Originality. A system of equations is obtained, which allows finding the optimal values of temperature thresholds for the detection of overheated roller and cassette boxes under the assumption that the error probabilities in the selection of boxes by their types are known and constant. Practical value. The developed method of adjusting the alarm settings of CTM makes it possible to significantly reduce unjustified train delays and the number of car uncouplings.

Assessing the impact of urban environment and green infrastructure on mental health: results from the São Paulo Megacity Mental Health Survey.

Different land cover types in cities, including green areas, have impacts on mental health. Few studies, however, have been conducted in megacities in low-/middle-income countries, which have extremely complex urban arrangements. We analyzed land cover using the population database of the São Paulo Megacity Mental Health Survey (n = 4287) and the associations with the diagnosis of depression/anxiety. Automatic classification of the orthophotos of the metropolitan area was performed using the random forest algorithm to provide land cover variables. The association of mental health data with land cover was determined with logistic regression and multilevel regression models. The percentage of different green spaces, mainly grassed areas, within districts was negatively associated with the presence of anxiety (OR 0.994, 0.968, 0.994, respectively), while roofs, asphalt and shadow (OR 1.007, 1.021, 1.085, 1.021, 1.014, respectively) were positively associated with the presence of anxiety. These results were more significant in green areas within the fourth quartile [-0.352 (0.158) and -0.347 (0.155), respectively] and in the roofs in the fourth quartile [0.321 (0.159)]. No significant results were found for depression. Our data indicate the need for intensive greenery in spaces with different vegetation compositions in urban environments, especially megacities, to improve the mental health of urban dwellers.

The fabrication of environmental intangibles as a questionable response to environmental problems

ABSTRACT This article proposes a general framework within which to analyze the new environmental intangibles that have been proliferating over the last decades in order to address environmental problems on a market basis. We pay attention to different possible states of environmental intangibles according to the degree of commodification of the impact they are based on. The impact is measured, then commodified and sometimes traded in a secondary market. Each state requires complex socio-technical arrangements. We also differentiate between positive impact, avoided negative impact and negative impact commodities, since each of them appears to relate to the environment problem quite differently. The literature and the articles of this special issue provide numerous case studies. They suggest that the commodification of environmental impacts via the creation of intangibles often fails to deliver the promised environmental improvements. We throw light on one of their aspects: the detachment from the physicality of the impacts, a detachment that is needed to commodify them. This detachment takes different guises. It seems that the greatest flexibility for economic actors comes with a greater detachment, and that this weakens its environmental effectiveness.

Evaluation of calcium alginate bead formation kinetics: An integrated analysis through light microscopy, rheology and microstructural SAXS

Ca(II)-alginate beads are being produced for a broad spectrum of biotechnological uses. Despite the simplicity of their manufacturing process, in these highly complex arrangements, the final properties of the material strongly depend on the supramolecular scaffolding. Here we present a cost-effective automatized Optical Video Microscopy approach for in situ evaluation of the kinetics of alginate bead formation. With simple mathematic modeling of the acquired data, we obtained key parameters that reveal valuable information on the system: the time course of gel-front migration correlates with the plateau of the storage module, and total volume shrinkage is highly related to the stabilization of shear strain and shear stress at the yield point. Our results provide feasible and reproducible tools, which allow for a better interpretation of bead formation kinetics and a rapid screening technique to use while designing gelling materials with specific properties for technological applications.

3D Bioprinting-Based Vascularized Tissue Models Mimicking Tissue-Specific Architecture and Pathophysiology for in vitro Studies.

A wide variety of experimental models including 2D cell cultures, model organisms, and 3D in vitro models have been developed to understand pathophysiological phenomena and assess the safety and efficacy of potential therapeutics. In this sense, 3D in vitro models are an intermediate between 2D cell cultures and animal models, as they adequately reproduce 3D microenvironments and human physiology while also being controllable and reproducible. Particularly, recent advances in 3D in vitro biomimicry models, which can produce complex cell structures, shapes, and arrangements, can more similarly reflect in vivo conditions than 2D cell culture. Based on this, 3D bioprinting technology, which enables to place the desired materials in the desired locations, has been introduced to fabricate tissue models with high structural similarity to the native tissues. Therefore, this review discusses the recent developments in this field and the key features of various types of 3D-bioprinted tissues, particularly those associated with blood vessels or highly vascularized organs, such as the heart, liver, and kidney. Moreover, this review also summarizes the current state of the three categories: (1) chemical substance treatment, (2) 3D bioprinting of lesions, and (3) recapitulation of tumor microenvironments (TME) of 3D bioprinting-based disease models according to their disease modeling approach. Finally, we propose the future directions of 3D bioprinting approaches for the creation of more advanced in vitro biomimetic 3D tissues, as well as the translation of 3D bioprinted tissue models to clinical applications.

Structure and properties of Al2O3-bonded porous fibrous YSZ ceramics fabricated by aqueous gel-casting

To meet requirements for high porosity and high strength, novel aqueous gel-casting process has been successfully developed to fabricate Al2O3-bonded porous fibrous YSZ ceramics with ρ-Al2O3 and YSZ fibers as raw materials. Microstructure, phase composition, apparent porosity, bulk density, thermal conductivity, and compressive strength of fabricated porous ceramics were investigated, and effects of fiber content on properties were discussed. According to results, bird nest 3D mesh with interlaced YSZ fibers and Al2O3 binder was formed, ensuring the ability to obtain high performance, lightweight ceramics. An increase in the number of YSZ fibers led to more complex interlaced arrangement of fibers and denser network structure of porous ceramics at retaining their stability. Furthermore, their apparent porosity and bulk density increased, whereas thermal conductivity and compressive strength decreased with increasing the fiber content. In particular, comparatively high porosity (71.1–72.7%), low thermal conductivity (0.209–0.503 W/mK), and relatively high compressive strength (3.45–4.24 MPa) were obtained for as-prepared porous ceramics, making them promising for applications in filters, thermal insulation materials, and separation membranes.

Mapping the cross-border cooperation ‘galaxy’: an exploration of scalar arrangements in Europe

ABSTRACT The development of cross-border regionalism in Europe has given rise to a multitude of academic works focussing on the pattern, signification and evolution of cross-border cooperation. Most previous studies have, however, focused on individual cross-border cooperation initiatives as units of analysis and neglected their spatial relation to other initiatives. By mapping the perimeter, activity, geographical type, scale and spatial relations of 209 initiatives, the current paper provides an updated and more nuanced overview of the geography of cross-border cooperation in Europe. The cartographic exploration from a rescaling perspective reveals the varying accumulation, scalar focus and activity of cross-border cooperation across Europe and leads to the identification of different forms and evolutions of scalar arrangements constituted by their overlapping perimeters of action. The distinction between nested, overlapping and complex arrangements suggests that different scalar processes are involved in the ongoing structuration of cross-border cooperation, and calls for better consideration of these multi-scalar dynamics in future research.