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The Mabujina Complex exposed in south-central Cuba consists of an elongated body of metamorphosed volcanic and subvolcanic mafic rocks and tonalitic gneisses. The complex is largely composed of greenschist facies rocks (Porvenir Formation) directly below the Cretaceous volcanic arc section and of a deeper sequence of deformed amphibolite facies rocks (Mabujina Amphibolite Complex). The origin of the protolith of the Mabujina Complex has been the subject of intense debate in the past. While some authors consider the Mabujina Complex to represent the deepest and oldest (Early Cretaceous) exposed section (root) of the Cretaceous Caribbean volcanic arc others suggested an exotic (non-Caribbean related) Early Cretaceous volcanic arc section. The later proposal implies the tectonic emplacement underneath the Caribbean arc of a segment of the Pacific-related Early Cretaceous Mexican Guerrero volcanic arc terrane. A new set of whole-rock geochemical analyses presented in this study shows that the protoliths of the Mabujina Amphibolite Complex constitute an island-arc sequence with a) less abundant island-arc tholeiitic mafic rocks similar to the Early Cretaceous tholeiitic island arc of the Caribbean and b) dominant transitional to calc-alkaline mafic and felsic igneous rocks that resemble the Early to Late Cretaceous magmatism of the Caribbean arc. The high initial Nd ratios of the rocks from the Mabujina Amphibolite Complex are indistinguishable from the tholeiitic to calc-alkaline sequences from the Caribbean arc, reflecting a depleted MORB mantle source with limited subduction-related component input. The present data, together with published geochemical and geochronological data of the protoliths, allow identifying a Caribbean origin for the Mabujina Complex instead of an exotic provenance in the Guerrero Arc of western Mexico. However, even if the interpretation of the geochemical data favours a Caribbean origin, the Mabujina Amphibolite Complex cannot represent the root of the volcanic arc. Here, we propose that the Mabujina Amphibolite Complex is a fragment of the Early to Mid-Cretaceous Caribbean arc that was tectonically emplaced below this same arc as a likely consequence of arc segmentation and strike-slip trans-compression triggered by oblique subduction during the mid-Cretaceous. [ABSTRACT FROM AUTHOR]

This study investigates the slip system activities in primary α grains of a forged Ti–6Al–4V alloy under pure fatigue and dwell-fatigue conditions, using high-resolution digital image correlation (HR-DIC) analysis obtained through interrupted mechanical tests. A quantitative examination of operating slip systems and strain localization on large-field HR-DIC data is conducted using an automated analysis framework developed in a previous study. The findings reveal higher slip activities under dwell-fatigue conditions, evidenced by parameters such as slip band density, area fraction of grains activated with slips, and mean equivalent plastic strain intensities along slip bands through statistically sound analysis. A notable shift in dominant slip activity from basal slips to prismatic slips is observed under pure fatigue conditions, while dominant prismatic slip activity persists throughout dwell-fatigue processes. Furthermore, slip bands with early-developed high strain localization, referred to as slip markings, are identified as prerequisites for surface crack initiation, and three types of slip markings are discovered. Finally, possible reasons for dwell-life debits, and potential anisotropy in the two major slip systems, basal and prismatic slips, are discussed. • Slip system activities are analyzed for bimodal Ti–6Al–4V under pure fatigue and dwell-fatigue conditions. • Quantitative analysis on slip band activities is obtained through large-field HR-DIC data. • Similarities and differences in slip band activities are identified for different conditions. • Cracks are observed on slip band with early developed high strain localization in dwell-fatigue. • Anisotropic slip behaviors between basal and prismatic slips are discovered. [ABSTRACT FROM AUTHOR]

• A brand-new two-step reaction mechanism of ONA electrode is proposed in AIB. • The π-π stacking structures of π-COCs can contribute capacity directly. • The ONA show the co-existence of high capacity and excellent cycle stability in AIB. Π-conjugated organic compounds (π-COCs), as a potential electrode material, mainly emphasized the effects of functional groups and intramolecular π-conjugated system on charge storage in the past studies. In this work, we discovered a brand-new two step energy storage mechanism for π-COCs using oligomeric naphthalene (ONA) with intermolecular π-π stacking structure as electrode material in Al ion battery system. The electrochemical reaction of ONA is identified as the synergistic work of the chemical-adsorption of AlCl 4 - anions at low potential and the π···[AlCl 4 ]···π interaction at high potential. Based on this, the Al-ONA battery exhibits an excellent electrochemical performance (high specific capacity of 450 mAh/g at 0.1 A/g, long cycle life without attenuation for 4000 cycles at 1 A/g). This discovery of the energy storage mechanism, especially for the π···anion···π interaction, for π-COCs materials opens the door to exploring high performance organic electrode materials in energy storage field. [ABSTRACT FROM AUTHOR]

Cylindrical organs, e.g., blood vessels, airways, and intestines, are ubiquitous structures in biomedical optical imaging analysis. Image segmentation of these structures serves as a vital step in tissue physiology analysis. Traditional model-driven segmentation methods seek to fit the structure by constructing a corresponding topological geometry based on domain knowledge. Classification-based deep learning methods neglect the geometric features of the cylindrical structure and therefore cannot ensure the continuity of the segmentation surface. In this paper, by treating the cylindrical structures as a 3D graph, we introduce a novel contour-based graph neural network for 3D cylindrical structure segmentation in biomedical optical imaging. Our proposed method, which we named CylinGCN, adopts a novel learnable framework that extracts semantic features and complex topological relationships in the 3D volumetric data to achieve continuous and effective 3D segmentation. Our CylinGCN consists of a multiscale 3D semantic feature extractor for extracting inter-frame multiscale semantic features, and a residual graph convolutional network (GCN) contour generator that combines the semantic features and cylindrical topological priors to generate segmentation contours. We tested the CylinGCN framework on two types of optical tomographic imaging data, small animal whole body photoacoustic tomography (PAT) and endoscopic airway optical coherence tomography (OCT), and the results show that CylinGCN achieves state-of-the-art performance. Code will be released at https://github.com/lzc-smu/CylinGCN.git. • First contour-based model for cylinder-object segmentation in bio-optical imaging. • CylinGCN fuses local semantic and object topology for accurate segmentation. • Attention mechanism, customized graph structure and loss functions are introduced. • CylinGCN achieves state-of-the-art performance in PAT and OCT imaging datasets. [ABSTRACT FROM AUTHOR]